Dissertations / Theses on the topic 'Other environmental engineering and related engineering'
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Barlow, McKenzie Lee. "Comparative Analysis of Physiological Measurements and Environmental Metrics on Predicting Heat Stress Related Events." DigitalCommons@CalPoly, 2018. https://digitalcommons.calpoly.edu/theses/1906.
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Exposure to high heat and humidity can lead to serious health risks, including heat exhaustion and heat stroke. Wet Bulb Globe Temperature (WBGT) and heat index have historically been used to predict heat stress events, but individualized factors are not included in the measurement. It has been shown that there is a relationship between cardiovascular measurements and heat stress, which could be used to measure heat stress risk on an individual level. Research has been done to find relationships between cardiovascular metrics in a workplace environment, however the study did not include the use of a controlled environment as a baseline. This study provides measurements of transepidermal water loss (TEWL), heart rate, body core temperature, and blood pressure in a controlled environment when human subjects are exposed to high heat and humidity. Thirty subjects (n=17 females, 13 males) were asked to self-express their activity level (active vs. sedentary), gender, and age. The subjects performed a 30-minute moderate exercise routine on a stationary stepper machine in a heated environmental chamber (average WBGT of 26ºC). TEWL, heart rate, tympanic temperature, and blood pressure were recorded at every 10-minute increment of the exercise protocol per subject. The data was analyzed using JMP® software to find significant (P
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Liapodimitris, Dimitrios. "VESSEL FLEET OPTIMISATION FOR OFFSHORE WIND POWER MAINTENANCE." Thesis, Uppsala universitet, Institutionen för geovetenskaper, 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-332005.
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Wind power has been a leading energy source in the renewable energy sector. The offshore wind power industry is rapidly growing, having the advantages of great wind resources, with minimum impact on residential areas; however, the high O&M costs add significantly to the LCOE, and present a challenge to the project developers and operators. The objective of this Thesis is to develop an optimisation method aiming to optimise the O&M vessel fleet in terms of its size and mix, and implement it into a spreadsheet-based tool. At first, a review on the available literature was conducted, in order to establish the theoretical background on the topics of maintenance, optimisation and O&M vessels, and identify the O&M strategies used in offshore wind power. The optimisation method developed focuses on the implementation of different O&M strategies,and is mainly based on the vessel contracts strategy, which aims to acquire lease contracts of various vessel types, including helicopters, available in the market to support the maintenance activities of an offshore wind farm. The model developed consists of calculation modules and introduces a 5-stage weather data filtering process for the estimation of the operational weather window, a WT components' failures forecast method, and a 2-stage optimisation process. The model was applied on a case study of a fictitious offshore wind farm, by using measured and realistic input data, in order to examine its efficacy. The model's outputs generated presented the optimal O&M vessel fleet for three different scenarios (mean, best case, and worst case), together with the optimal allocation of the failure repairs to each O&M vessel, and the corresponding O&M costs.
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Widforss, Aron. "Teaching Machines to Recognise Avalanche Conditions." Thesis, Luleå tekniska universitet, Institutionen för system- och rymdteknik, 2021. http://urn.kb.se/resolve?urn=urn:nbn:se:ltu:diva-86876.
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Avalanche forecasting is an iterative process, where forecasters use weather data and snow observations in addition to previous assessments to conclude what forecast to publish. This project investigates how the forecasting process could be automated, using three seasons worth of data from 23 of Norway’s avalanche forecasting regions. Three scenarios were considered, using different amounts of input parameters based on what data would be available to the model in each respective scenario. For each scenario a machine learning model was trained, and a separate naïve model was constructed. The machine learning model could only beat the naïve model in the simplest scenario, using only weather data. In the other scenarios it was found that the data representation was lacking; highly intermittent snow observation data was structured as timeseries when a more preprocessed representation may have been more fruitfulSnow Models and Automatization in Geohazard-Forecasting
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Bascunan, Daniel. "LCC-analys parametrar för underhåll av inklädda tunnlar." Thesis, Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, 2020. http://urn.kb.se/resolve?urn=urn:nbn:se:ltu:diva-80926.
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Syftet med detta examensarbete är att undersöka och få fram underhållsparametrar för LCC-analysen (LivsCykelKostnad) av de nya inklädda tunnlarna. För arbetet har elektroniska källor använts samt intervjuer med tre yrkesverksamma från Trafikverket gällande bergtunnlar och de inklädda tunnlarna. Arbetet undersökte inte skillnaden mellan olika typer av tunnlar samt inkluderar inte utforskandet av andra länders LCC-analys parameterval. Trafikverket är en Svensk myndighet vars uppgift är att ansvara för och upprätthålla Sveriges transportsystem. Trafikverket har verksamhet inom sex områden: planering, trafik, underhåll, investering, stora projekt samt informations- och kommunikationsteknik. Huvudsakligen finns det två inklädnadssystem, fullinklädd, i vilket används antingen prefabricerad betong eller plastingjuten betong som inklädnad runt tunnel, samt halvinklädd, då en duk/membran med- eller utan sprutbetong används. Dessa inklädnadsystem har i uppgift att ta hand om vattenläckage och isbildning i tunneln. Fullinklädnad kan också användas som bärande element. En lättinklädd tunnel kan bestå av följande delar: duk/membranet, brandskydd, täckande nät, infästningsbultar och mindre delar. En fullinklädd tunnel består av antingen prefabricerad betong eller plastingjuten betong. Underhåll görs för att säkerställa den fortlöpande användningen av tunneln/anläggningen genom att åtgärda skador och fel som har uppkommit. En tunnel kan få skador på själva berget eller materialet. Underhåll av tunnlar består av flera steg. Först ut är tillståndsmätning, sedan objektplanering och sist åtgärd. En viktig del av åtgärd är trafikupphållet som uppstår när den utförs, kostnaden som uppstår påverkas av var tunneln är och hur länge det tar att åtgärda felet. LCC-analys är ett system som ger ett mått på ett objekts totalkostnad under dess hela livstid. LCC används på systemnivå för analys av tunnlarna och för att jämföra olika investeringsmetoder. För att utföra LCC-analys på systemnivå måste gränser för analysen sättas upp, LCC-modell och indata väljas. LCC-metoden som redovisas i rapporten använder investeringskostnaden och nuvärdet av underhållet- samt driftstoppskostnaden för att få fram LCC-värdet av underhållet för en komponent. Utifrån källorna och intervjuerna har det framgått att de avgörande parametrarna för LLC-analysen är följande: bergets tillstånd, materialets/konstruktionens tillstånd, kostnader för avstängning samt kostnaden för att ta ner inklädnaden.
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Widforss, Aron. "Avalanche Visualisation Using Satellite Radar." Thesis, Luleå tekniska universitet, Institutionen för system- och rymdteknik, 2019. http://urn.kb.se/resolve?urn=urn:nbn:se:ltu:diva-74556.
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Avalanche forecasters need precise knowledge about avalanche activity in large remote areas. Manual methods for gathering this data have scalability issues. Synthetic aperture radar satellites may provide much needed complementary data. This report describes Avanor, a system presenting change detection images of such satellite data in a web map client. Field validation suggests that the data in Avanor show at least 75 percent of the largest avalanches in Scandinavia with some small avalanches visible as well.Lavinprognosmakare är i stort behov av detaljerad data gällande lavinaktivitet i stora och avlägsna områden. Manuella metoder för observation är svåra att skala upp, och rymdbaserad syntetisk aperturradar kan tillhandahålla ett välbehövt komplement till existerande datainsamling. Den här rapporten beskriver Avanor, en mjukvaruplattform som visualiserar förändringsbilder av sådan radardata i en webbkarta. Fältvalidering visar att datan som presenteras i Avanor kan synliggöra minst 75 procent av de största lavinerna i Skandinavien och även vissa mindre laviner.
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Sandhi, Arifin. "ARSENIC REMOVAL BY PHYTOFILTRATION AND SILICON TREATMENT : A POTENTIAL SOLUTION FOR LOWERING ARSENIC CONCENTRATIONS IN FOOD CROPS." Doctoral thesis, KTH, Mark- och vattenteknik, 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-203995.
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Use of arsenic-rich groundwater for crop irrigation can increase the arsenic (As) content in food crops and act as a carcinogen, compromising human health. Using aquatic plant based phytofiltration is a potential eco-technique for removing arsenic from water. The aquatic moss species Warnstorfia fluitans grows naturally in mining areas in northern Sweden, where high concentrations of arsenic occur in lakes and rivers. This species was selected as a model for field, climate chamber and greenhouse studies on factors governing arsenic removal and arsenic phytofiltration of irrigation water. The arsenic and silicon (Si) concentrations in soil, water and plant samples were measured by AAS (atomic absorption spectrophotometry), while arsenite and arsenate species were determined using AAS combined with high pressure liquid chromatography (HPLC) with an anion exchange column. The arsenic content in grains of hybrid and local aromatic rice (Oryza sativa) cultivars with differing arsenic accumulation factor (AF) values was investigated in an arsenic hotspot in Bangladesh. The results showed that arsenic AF was important in identifying arsenic-safer rice cultivars for growing in an arsenic hotspot. The study based on silicon effect on arsenic uptake in lettuce showed that arsenic accumulation in lettuce (Lactuca sativa) could be reduced by silicon addition. The aquatic moss had good phytofiltration capacity, with fast arsenic removal of up to 82% from a medium with low arsenic concentration (1 µM). Extraction analysis showed that inorganic arsenic species were firmly bound inside moss tissue. Absorption of arsenic was relatively higher than adsorption in the moss. Regarding effects of different abiotic factors, plants were stressed at low pH (pH 2.5) and arsenic removal rate was lower from the medium, while arsenic efflux occurred in arsenate-treated medium at low (12°C) and high (30°C) temperature regimes. Besides these factors, low oxygenation increased the efficiency of arsenic removal from the medium. Finally, combining W. fluitans as a phytofilter with a lettuce crop on a constructed wetland significantly reduced the arsenic content in edible parts (leaves) of lettuce. Thus W. fluitans has great potential for use as an arsenic phytofilter in temperate regions.QC 20170323
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Ngo, Phuong Linh. "Detection of in-plane orbital manoeuvres from a catalogue of geostationary objects." Thesis, Luleå tekniska universitet, Rymdteknik, 2020. http://urn.kb.se/resolve?urn=urn:nbn:se:ltu:diva-81475.
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The number of man-made space objects is dramatically growing nowadays. The continuous monitoring and studying of these objects are necessary to keep their number under control and ensure safe space operations. With respect thereto, international guidelines recommend decongesting the most populated space regions from satellites arriving at the end of their operational lifetime by performing post-mission disposal strategies. In general, a satellite is considered to be functional if it is still performing periodic manoeuvres to stay within the orbital operation configuration. This study presents a promising method to detect historical in-plane manoeuvrers of satellites on a geostationary orbit (GEO). Since a manoeuvrer changes the orbital state of the spacecraft, its effect can be detected by comparing the observed data to a reference evolution. In this case, the model is represented by the dynamical model STELA based on a semi-analytical theory. The observed data is provided by the public American space object catalogue. The Two-line element (TLE) database contains the orbital state of each tracked object, however, not all six orbital parameters are interesting to study in terms of in- plane manoeuvrers. The evolution of the longitude and of the eccentricity vector is immediately affected by a manoeuvre that changes the shape or the size of an orbit. Within the longitude analysis, the manoeuvre epoch is estimated by focusing on the manoeuvre strategy. An operational spacecraft usually performs a manoeuvre as soon as the longitude motion threatens to violate the operational deadband. Consequently, the longitude evolution follows a parabolic motion. Two polynomial curves of second degree are laid over the observation: the first curve is derived from a simplified dynamical model and the second curve is directly obtained through a Least Squares (LS) fitting method. The discrepancy between the LS and physical fitted parabolas gives an indication on the quality of the input data, that is to say, of the TLEs. The detected manoeuvre epoch must be companioned by a confidential parameter that denotes the time range around the estimated epoch in which the manoeuvre is expected to have happened. The manoeuvre interval is then forwarded to the eccentricity analysis where the manoeuvrer epoch is estimated more precisely by studying the divergence between the observed and expected eccentricity vector evolution. The latter is propagated with STELA after having estimated the area-to-mass ratio that is needed in order to model the perturbation effects accurately upon which the performance of the dynamical reference model strongly depends. As soon as the observed eccentricity vector deviates significantly from the expected evolution, the epoch and the velocity ΔV of the manoeuvre can be recovered, too.
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Sigfridson, Marcus. "Skyddsinfiltrationens influensområde för en fallstudie : - modellering och osäkerheter." Thesis, Uppsala universitet, Luft-, vatten och landskapslära, 2019. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-390702.
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För att uppskatta influensområdet till följd av skyddsinfiltartion finns ett antal analytiska modeller att tillämpa. Dessa modeller tar hänsyn till parametrar så som hydraulisk konduktivitet och magasinkoefficient, men de följer också med en rad antaganden som i praktiken inte kan uppfyllas. En alternativ tillvägagång för att bestämma influensområdet är därför med hjälp av numeriska modeller, som i större grad kan göras platsspecifika. Numeriska modeller är till följd av detta mer tidskrävande och behöver mer indata. I denna studie undersöktes vilken metod som är bäst lämpad för att bestämma skyddsinfiltrationens influensområden för en fallstudie i Bromstens industriområde, belägen cirka 15 km nordväst om Stockholm centrum. Två numeriska modeller med varierande underlag av platsspecifika data utvecklades över områdets geologi och grundvattenmagasin för att kunna simulera grundvattennivåer med och utan infiltration. Utöver detta beräknades influensområdet med fyra analytiska modeller. Modellerna testades sedan utifrån olika scenarion, där såväl dataupplösning som den platsspecifika kännedomen över området stegvis ökades. Platsspecifika data tillkom till följd av geotekniska undersökningar och hydrogeologiska tester. Studien ämnar även att besvara vilken data som är av störst vikt för att bestämma influensområdet med de analytiska respektive numeriska modellerna samt vilka skillnader som uppstår mellan analytiskt beräknade influensområden och numeriskt simulerade influensområden. Resultaten visar att de numeriska modellerna i huvudsak är känsligast med avseende på den hydrauliska konduktiviteten, samt att den enklare numeriska modellen är känslig för magasinkoefficienten, något som indikerar att denna modell inte uppnår jämvikt i enlighet med vad som observerats i fält. Utöver detta stod det klart att vattenavgivningstalet inte hade någon nämnvärd inverkan på resultaten. Bland de analytiska modellerna råder den största känsligheten i magasinkoefficienten, följt av konduktiviteten. För Sichardts formel, som inte tar hänsyn till magasinkoefficienten var konduktiviteten den känsligaste parametern. Akvifärens mäktighet, vilken reviderades mellan scenario 2 och 3, hade ingen betydande inverkan på de analytiska modellerna. Vidare visade infiltrationstestet på stora skillnader i skyddsinfiltrationens influensområde med avseende på de olika modellerna och dataunderlaget. Den minsta avvikelsen mätt i residualer observerades för den komplexa numeriska modellen under scenario 4, vilket motsvarar det scenario då dataunderlaget var som störst. Trots att detta scenario tillsammans med modell anses vara det dyraste fallet, anses detta vara det bästa och samtidigt mest tillförlitligt metoden för att uppskatta skyddsinfiltrationens influensområde.To evaluate the area of influence due to artificial infiltration several analytical models are available. Some of the parameters taken into account by these models are the hydraulic conductivity and storage coefficient, but with these models some assumptions, which in reality cannot be fulfilled, are made. An alternative approach to evaluate the area of influence is therefore with numerical models, which in a greater extent account for the site-specific conditions. Due to this, numerical models are more time consuming and require more input data. This project aims to investigate the most effective approaches to evaluate the area of influence due to artificial infiltration for a case study in Bromsten, located 15 kilometers northwest of Stockholm. Two numerical models, with different background data due to the extent of site knowledge, were developed to represent the site's geological settings and groundwater properties to simulate the groundwaterlevels with and without infiltration. Moreover the area of influence were calculated with four analytical models. All of the models were then applied on four different scenarios, in which the data resolution and the site knowledge increased. Site-specific data was added as a result of geological surveys and hydrogeological tests. The study also aims to answer which data is most important in order to determine the area of influence with analytical and numerical models and what differences there are between the analytical solutions compared with the numerical solutions. Among the methods investigated, constructing a more complex model with data from scenario 4, the scenario with the greatest data supply, resulted in the most reliable results and was therefore the best method and the method to choose for this case-study. Other results indicated that the numerical models first of all are sensitive to the conductivity and that the more simpel numerical model is sensitive to the storage coefficient as well. The last result shows that this model does not reach the steady state conditions as observed in field, which highlights the importance of goetechnical investigation for the numerical models. Moreover none of the numerical models were sensitive to the specific yield. Among the analytical models the storage coefficient was the most important followed by the conductivity. For one of the analytical models (Sichardts formula) the conductivity was the most sensitive parameter. The thickness of the aquifer had no significant impact on the analytical models.
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Johansson, Kling Erika. "Trafikinducerade vibrationer : En studie om busskuddars påverkan på vibrationsnivåer i mark och byggnader." Thesis, Uppsala universitet, Institutionen för geovetenskaper, 2019. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-382877.
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Trafikinducerade vibrationer: En studie om busskuddars påverkan på vibrationsnivåer i mark och byggnader. Erika Johansson Kling I Uppsala används busskuddar som en form av medveten ojämnhet i vägbanan för att sänka hastigheten och öka trafiksäkerheten på olycksdrabbade vägsträckor. Boende i bostäder belägna nära busskuddar har dock rapporterat att de ibland kan uppleva vibrationer kopplade till då tunga fordon passerar busskuddar som störande. Denna studie syftade till att kvantifiera vibrationsnivåer i mark och byggnader nära busskuddar samt utreda centrala faktorer som kan påverka vibrationsnivån och vibrationsutbredningen. Genom vibrationsmätningar i fält på fyra platser i Uppsala samlades data in och analyserades utifrån angivna frågeställningar. Resultatet bekräftade det som litteraturstudien belyste, att det är svårt att på ett generellt sätt beskriva vibrationsutbredningen och att den tydligt är platsspecifik. Vid samtliga undersöka platser kunde dock konstateras att vibrationsnivån i marken tenderar att vara en faktor mellan 2,5–32 högre då ett tungt fordon passerar en busskudde, jämfört med då det passerar en opåverkad referenspunkt längs med samma väg. Generellt avtog dessutom vibrationsnivån i marken med ökat avstånd från källan. Vilken vibrationsled som dominerade varierade dock både mellan platserna och för olika avstånd från källan. Vid en av de fyra mätplatserna förstärktes vibrationsnivån i byggnaden, jämfört med i marken utanför. Vid samma mätplats överskreds dessutom känseltröskeln inomhus, och en skyddsvibrationsnivå på 0,5 mm/s kan behöva tillämpas vid busskudden för att förhindra detta. Mätningarna visade att både vibrationer med låga och höga frekvenser kan uppstå i marken nära busskudden då tunga fordon passerar. Dock var det enbart vibrationer med låga frekvenser som spreds vidare i marken vid ett ökat avstånd från källan. Studien visade dessutom att det kan krävas ett skyddsavstånd mellan busskudde och byggnad på cirka 100 meter för att känseltröskeln inte ska riskera att överskridas inomhus. Trots att ett sådant avstånd är platsspecifikt, belyser det vilka krav det skulle kunna ställa på samhällsbyggnaden i ett växande Uppsala. Det faktum att busskuddar kan förhöja vibrationsnivån i marken vid passage av tunga fordon ter sig något märkligt, då busskuddarna ska vara utformade på ett sätt som tillåter tunga fordon att passera relativt obehindrat. Fler studier kring busskuddarnas utformning och/eller grundläggning är därför av stor relevans. Det är vidare relevant att exempelvis utreda hur fordonens hastighet över busskuddar påverkar vibrationsnivån i marken, då litteraturstudien belyser att det främst är då tunga fordon passerar ojämnheter med hög hastighet som betydande vibrationer kan uppstå. Busskuddar anses vara en av de mest effektiva hastighetssänkande åtgärderna, men studien visar att det kan ske på bekostnad av ökade vibrationsnivåer. En grundläggande helhetsbedömning bör därför göras av busskuddarnas lämplighet vid kommande stadsplanering. Nyckelord: markvibration, vibrationsmätning, busskudde, trafik, samhällsbyggnad. Institutionen för geovetenskaper, Uppsala Universitet, Villavägen 16, SE-752 36 Uppsala. ISSN 1401–5765.Traffic induced vibrations: A study on the effect of speed control cushions on vibration levels in surrounding land and buildings. Erika Johansson Kling In Uppsala, speed control cushions are used as a form of conscious unevenness in the road surface to reduce speed and increase road safety on accident-affected road sections. However, housing in residences located near speed control cushions have reported that they can sometimes experience vibrations linked to when heavy vehicles pass speed control cushions as disturbing. This study aimed to quantify vibration levels in land and buildings near speed control cushions and to investigate key factors that can affect the vibration level and vibration propagation. Through vibration measurements at four places in Uppsala, data was collected and analyzed based on the stated research questions. The result confirmed what the literature study highlighted, that it is difficult to describe the propagation of vibrations in a general way and that it is clearly site-specific. However, it was found at all the measurement sites that the vibration level in the ground tends to be a factor between 2.5 and 32 higher when a heavy vehicle passes a speed control cushion, compared to when it passes an unaffected reference point along the same road. Generally, the vibration level in the ground also decreased with increased distance from the source. However, the level of vibration that dominated varied between the locations and for different distances from the source. At one measurement site, the vibration level in the building was amplified compared to in the ground outside. At the same measurement site, the sensing threshold was also exceeded indoors, and a protection vibration level of 0.5 mm/s may have to be applied nearby the speed control cushions to prevent this from happening. The measurements showed that both vibrations with low and high frequencies can occur in the ground near the speed control cushions when heavy vehicles pass. However, it was only vibrations with low frequencies that propagated further in the ground at an increased distance from the source. The study also showed that a safety distance between speed control cushions and buildings of approximately 100 meters may be required in order for the sensitivity threshold not to be exceeded indoors. Although such a distance is sitespecific, it highlights what requirements it could put on the urban planning in a growing Uppsala. The fact that speed control cushions can increase the level of vibration in the ground when heavy vehicles pass seems somewhat strange, since the speed control cushions are supposed to be designed in a way that allows heavy vehicles to pass relatively unobstructed. Additional studies on the design and/or foundation of the speed control cushions are therefore of great relevance. It is furthermore relevant to investigate, for example, how the speed of the vehicles when passing over speed control cushions affects the vibration level in the ground, since the literature study highlights that it is primarily when heavy vehicles pass an unevenness in the road surface at high speed that significant vibrations can occur. Speed control cushions are considered to be one of the most effective speed reducing measures, but the study shows that they may lead to increased vibration levels. An overall 3 evaluation should therefore be made regarding the suitability of speed control cushions in future urban planning. Keywords: ground vibration, vibration measurement, speed control cushion, traffic, urban planning. Department of Earth Sciences, Uppsala University, Villavägen 16, SE-752 36 Uppsala. ISSN 1401–5765.
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Sefer, Birhan. "Environment related surface phenomena and their influence on properties of Ti-6Al-4V and Ti-6Al-2Sn-4Zr-2Mo : oxidation at elevated temperature and corrosion during chemical treatment." Doctoral thesis, Universitat Politècnica de Catalunya, 2016. http://hdl.handle.net/10803/403884.
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This thesis covers investigation of the surface phenomena of Ti-6Al-4V and Ti-6Al-2Sn-4Zr-2Mo alloys related with oxidation at elevated temperature and corrosion during chemical treatment in hydrofluoric-nitric acid (HF/HNO3) solutions. The explored phenomena are related to manufacturing and service conditions of aero-engine components. During manufacturing and operation, the alloys are sunjected to elevated temperatures in oxygen environment. In such conditions an oxide on the surface and an oxygen enriched layer below the oxide, commonly referred as alpha-case is formed. Alpha-case is a hard and brittle layer that is detrimental to the mechanical properties and must therefore be completely eliminated. A conventional method for elimination of alpha-case is chemical processing in HF/HNO3 solutions, i.e. chemical milling.
Isothermal oxidation treatments in air at 500, 593 and 700 ºC for up to 500 hours were carried out in this thesis. Both alloys developed rutile type of oxide structure and Ti-6Al-2Sn-4Zr-2Mo exhibited stronger oxidation resistance than Ti-6Al-4V. Transition from parabolic to linear oxidation rate was observed at 700 ºC and = 200 hours for both alloys. The difference in the oxidation kinetics of the two alloys is suggested to be related with the chemical composition of the alloys. The oxygen enriched layer, i.e. alpha-case layer, was characterised and its thickness was measured using conventional metallographic and microscopic techniques. The parabolic rate constants, the oxygen diffusion parameters and activation energies were estimated in the temperature range of 500-700 ºC for both alloys. Moreover, the oxidation for 500 hours at 700 ºC resulted in microstructural changes and element re-distribution. The bulk and alpha-case layer hardness at micro- and nano-scale were measured using microhardness and nanoindentation techniques. The alpha-case layer had higher hardness due to the solid solution strengthening effect of the diffused oxygen.
The effect of chemical milling in 1:11 HF/HNO3 solution on the surface integrity, and the influence on low cycle fatigue (LCF) strength of cast Ti-6Al-2Sn-4Zr-2Mo alloy was investigated. Five and sixty minutes chemical processing times and three imposed total strain ranges in fatigue tests were evaluated. Significant drop in fatigue life was observed for the samples etched before LCF testing, as compared to the non-etched samples. The influence from etching was found to be most detrimental for fatigue samples tested at the lowest strain ranges. The fatigue life reduction was correlated with the number of crack initiation sites. Multiple crack initiation sites were observed for the etched samples, whereas only one crack initiation site was discerned in the non-etched samples. Inspection of the surface of the etched samples revealed selective and severely etched prior ß grain boundaries and pit formation at the triple joints of the prior ß grain boundaries. These surface defects were considered as stress raisers promoting an earlier fatigue crack initiation.
The influence of two molar concentration ratios of HF and HNO3 acids (1:3 and 1:11) on the corrosion behaviour of cast Ti-6Al-4V and Ti-6Al-2Sn-4Zr-2Mo were investigated by electrochemical and atomic force microscopy (AFM) techniques. The corrosion of the two alloys was a function of the concentration ratio of the acids and also of the alloys¿ chemical compositions. The AFM measurements showed faster dissolution rate of the a-phase than the ß-phase in the Widmanstätten microstructure. It was considered that the reason for this is formation of local micro-galvanic cells between the phases. Moreover, the Volta-potential was measured using scanning Kelvin probe force microscopy (SKPFM) and the obtained maps revealed difference in the Volta-potential between the a- and the ß-laths in both alloys. This observation strengthened the likelihood for formation and operation of micro-galvanic cells between the phases.En esta tesis doctoral se estudian los fenómenos superficiales relacionados con la oxidación a alta temperatura y la corrosión producidos durante el tratamiento químico en soluciones de ácido fluorhídrico-nítrico (HF-HNO3) en las aleaciones Ti-6Al-4V y Ti-6Al-2Sn-4Zr-2Mo. Estos fenómenos se producen durante la fabricación y el servicio de componentes para motores aeronáuticos, pues se dan condiciones de elevada temperatura en un ambiente rico en oxígeno, las cuales favorecen la formación de óxido en la superficie y también de una capa enriquecida en oxígeno debajo del óxido, comúnmente conocida como alpha-case o capa alfa. La alpha-case es una capa dura y frágil, perjudicial para las propiedades mecánicas, por lo que debe ser minimizada o totalmente eliminada. Un método convencional para eliminar la capa alfa es el procesado químico en soluciones de ácido fluorhídrico-nítrico, conocido como chemical milling. En este estudio se han efectuado tratamientos isotérmicos en aire a 500, 593 y 700 °C, con duración máxima de 500 horas. Ambas aleaciones desarrollaron óxido tipo rutilo, en tanto que la Ti-6Al-2Sn-4Zr-2Mo mostró mejor resistencia a la oxidación que la Ti-6Al-4V. Se observó una transición de la velocidad de oxidación de parabólica a lineal a 700 °C y tiempos = 200 horas, para ambas aleaciones. Las diferencias en la cinética de oxidación entre ambas aleaciones se han relacionado con su composición química. La capa rica en oxígeno, i.e. alpha-case, fue caracterizada y su espesor medido mediante técnicas metalográficas. Se observó que la velocidad de crecimiento de la capa alfa seguía una relación parabólica con el tiempo para ambas aleaciones. La difusión del oxígeno y la energía de activación se estimaron en el rango de temperaturas de 500-700 °C. Adicionalmente, se comprobé que el tratamiento isotérmico a 700 °C durante 500 horas dio lugar a cambios microestructurales y a la redistribución de elementos. Las durezas del interior y de la capa alfa se midieron a escalas micro- y nano- mediante técnicas de microdureza y nanoindentación. La capa alfa mostró mayor dureza debido al efecto de endurecimiento por solución sólida debido al oxígeno difundido. El efecto de la solución 1:11 HF-HNO3 en la integridad superficial y en la resistencia a fatiga en el régimen de oligofatiga (LCF = Low Cycle Fatigue) de la aleación Ti-6Al-2Sn-4Zr-2Mo fue investigado. Se evaluaron tiempos de procesado químico cortos y largos (5 y 60 minutos) y tres valores de amplitud de deformación total. Se observó una significativa disminución de la vida a fatiga para las muestras atacadas antes de los ensayos LCF, en comparación con las muestras no atacadas. La influencia del ataque se mostró más perjudicial a bajos valores de deformación impuesta. La reducción en la vida a fatiga se correlacionó con el número de zonas de iniciación de grietas. Múltiples zonas se observaron para las muestras atacadas, mientras que solo un lugar de nucleación de grieta se detectó para las no atacadas. La inspección de las superficies de las muestras atacadas reveló un ataque selectivo y severo en los bordes de grano prior beta y la formación de picaduras en los puntos triples de los bordes de grano prior beta. Estos defectos superficiales fueron considerados como exaltadores de tensiones que promueven la temprana nucleación de las grietas de fatiga. Se investigó la influencia en el comportamiento a corrosión de Ti-6Al-4V y Ti-6Al-2Sn-4Zr-2Mo de dos diferentes relaciones de concentración (1:3 y 1:11) de los ácidos HF y HNO3. Se emplearon para ello técnicas electroquímicas y microscopía de fuerza atómica (AFM). La corrosión de las dos aleaciones depende de la concentración de HF-HNO3 y posiblemente también de sus composiciones químicas. Las medidas de AFM revelaron una velocidad de disolución mayor de la fase alfa que de la beta en la microestructura tipo Widmanstätten. Se considera que la razón de esta disolución selectiva es la formación de celdas micro-galvánicas.
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Söderberg, Magnus. "Coupled models related to manufacturing simulations." Licentiate thesis, Luleå tekniska universitet, Material- och solidmekanik, 2014. http://urn.kb.se/resolve?urn=urn:nbn:se:ltu:diva-26698.
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Manufacturing simulations is today on a level where a manufacturingchain can be simulated including various steps such as machining, welding, metal deposition and heat treatment. This opens up for the possibility to investigate different manufacturing routes without the high costsof experimental work. In the case of welding and metal deposition theeffect of fixtures and ordering of weld sequences can be evaluated withrespect to deformation and residual stress. If a heated tool is included ina hot forming simulation there is a possibility to find process parameters that produces the desired microstructure in the sheet metal component.The work in this thesis has focused on techniques for increased effi-ciency in the context of large and complex structures and also alleviatingthe work during model definition for metal deposition and Joule heating.Godkänd; 2014; 20131125 (magsod); Nedanstående person kommer att hålla licentiatseminarium för avläggande av teknologie licentiatexamen. Namn: Magnus Söderberg Ämne: Materialmekanik/Material Mechanics Uppsats: Coupled Models Related to Manufacturing Simulations Examinator: Professor Lars-Erik Lindgren, Institutionen för teknikvetenskap och matematik, Luleå tekniska universitet Diskutant: Bitr. professor Mats Näsström, Institutionen för teknikvetenskap och matematik, Luleå tekniska universitet Tid: Fredag den 7 februari 2014 kl 09.00 Plats: E246, Luleå tekniska universitet
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Stewart, Mary. "Environmental life cycle considerations for design-related decision making in minerals processing." Doctoral thesis, University of Cape Town, 1999. http://hdl.handle.net/11427/22083.
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The objective of this work is to inform environmental decision making in design for the environment in minerals processing. To this end an integrated decision hierarchy has been developed. This decision hierarchy incorporates technical, environmental and social considerations in the design process. Life Cycle Assessment (LCA) has been chosen as the metric whereby environmental considerations will be included in the decision making process. LCA information is augmented by information from the Environmental Impact Assessment (EIA) process in detailed design. There are four themes in this thesis; Minerals Processing, Process Design, LCA and Decision Making. Considerations specific to process design in the minerals industry are highlighted. The use ofLCA as a tool to assess the environmental performance of the minerals industry is discussed. LCA is then used to inform the decisions taken during process design.
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Ashby, Joy. "An interactive environmental site assessment audit for Wagner Creek river basin clean up project." FIU Digital Commons, 2003. http://digitalcommons.fiu.edu/etd/1322.
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The primary purpose of this thesis was to design and create an Interactive Audit to conduct Environmental Site Assessments according to American Society of Testing Material's (ASTM) Phase I Standards at the Wagner Creek study area. ArcPad and ArcIMS are the major software that were used to create the model and ArcGIS Desktop was used for data analysis and to export shapefile symbology to ArcPad. Geographic Information Systems (GIS) is an effective tool to deploy these purposes. This technology was utilized to carry out data collection, data analysis and to display data interactively on the Internet. Electronic forms, customized for mobile devices were used to survey sites. This is an easy and fast way to collect and modify field data. New data such as land use, recognized environmental conditions, and underground storage tanks can be added into existing datasets. An updated map is then generated and uploaded to the Internet using ArcIMS technology. The field investigator has the option to generate and view the Inspection Form at the end of his survey on site, or print a hardcopy at base. The mobile device also automatically generates preliminary editable Executive Reports for any inspected site.
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Risemark, Eriksson Martin. "Environmental stress of electrical machine winding insulation." Thesis, Uppsala universitet, Elektricitetslära, 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-326711.
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The conducting winding of an electrical machine is insulated in order to prevent any short circuits to occur within the machine. This insulation is during its lifetime exposed to several environmental stresses and therefore plays an important role in the life length of the machine. Accelerated stress tests are used to investigate what design and material is most suitable for a good endurance of a product. In this master thesis, new accelerated test methods for the insulation system in an electrical machine are developed and evaluated. The study resulted in four stress tests that simulate the thermal stress, the thermomechanical stress and the ambient stress from direct oil cooling. Three diagnosis tests and a material analysis were used in order to evaluate how these accelerated stress test methods affected the insulation. The diagnosis tests showed no clear sign of deterioration of the insulation in terms of change in electrical characteristics. However, the material analysis indicated deterioration of the insulation, such as cracks and oxidation of the material. These changes show that the test methods are capable to affect the insulation, but will need more time to cause a breakdown, since a stator of this kind is expected to have a very long life length. Therefore, in future work on this topic, these test methods should continue for a longer time and it would likely be interesting to look into other diagnosis tests.
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Coker, Patricia A. "The Fundamentals of a Course on the Environmental Impacts of Ships." ScholarWorks@UNO, 2013. http://scholarworks.uno.edu/td/1624.
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Lidelöw, Sofia. "Environmental assessment of secondary construction materials." Licentiate thesis, Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, 2004. http://urn.kb.se/resolve?urn=urn:nbn:se:ltu:diva-26261.
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Process industry, construction and other comparable activities produce large quantities of waste with potential use in geotechnical applications. Prior to utilisation, an acceptably low risk of contamination to humans and the environment must be demonstrated. This work focuses on the identification and evaluation of critical factors for environmental assessments of secondary construction materials. The market potential and the main barriers for usage of industrial wastes were analysed and showed a good potential especially in urban areas. The main obstacle is the long and complicated permit process involved. Further, the lack of a general procedure to investigate the suitability of intended usage leads to inconsistent assessments. An evaluation of leachate emissions from a large-scale test road demonstrated the importance of construction design and site-specific field conditions on the potential environmental impacts. It was also shown that pollutant concentrations in leachate from secondary construction materials tend to become comparable, or for some pollutants, even lower than from rock materials. Different assessment methods and criteria to judge the acceptability of an intended use were reviewed and various methods were identified. However, a generic method to evaluate materials under various environmental conditions is lacking.Godkänd; 2004; 20070109 (mlk)
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Ruggaber, Gordon J. (Gordon John) 1963. "Dynamics of particle clouds related to open-water sediment disposal." Thesis, Massachusetts Institute of Technology, 2000. http://hdl.handle.net/1721.1/9009.
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Thesis (Ph.D.)--Massachusetts Institute of Technology, Dept. of Civil and Environmental Engineering, 2000.Includes bibliographical references (p. 235-241).
Open-water disposal and capping is a promising solution for disposing of the 14 to 28 million m3 of contaminated sediment dredged annually in the United States (National Research Council, 1997). Such practice raises concerns about the feasibility of accurately placing the material in a targeted area and the loss of material to the environment during disposal. To better predict the fate of these materials, the objective of this research was to gain new insight into the physical processes governing the mechanics of their convective descent. Instantaneously released sediments form axisymmetric "clouds" resembling selfsimilar thermals. Current particle cloud models employ thermal theory and an integral approach using constant entrainment (a), drag (CD), and added mass (k) coefficients. The aim of this study was to investigate how real sediment characteristics (particle size, water content, and initial momentum) affect cloud behavior (i.e., velocity, growth rate, and loss of particles) and time variations in a, CD, and k. Flow visualization experiments were conducted using a glass-walled tank, special sediment release and capture (i.e., "trap") mechanisms, and various cohesive and non-cohesive particles. Particle sizes were scaled to real-world dimensions through the cloud number (Nc), defined as the ratio of the particle settling velocity to the characteristic cloud velocity. An "inverse" integral model was developed in which the conservation equations were solved for a and k using measured velocity and radius data. Based on the "inverse" model results, particle cloud experiments were simulated with an integral model using constant and time-varying a and k. The non-cohesive sediments evolved rapidly into "thermals" with asymptotic deceleration and large growth rates (a = 0.2 - 0.3). The particles eventually organized into "circulating thermals," with linear growth rates obeying buoyant vortex ring theory. In this phase, large particles (Nc > 10-) produced laminar-like vortex rings with small a (0.1 - 0.2). Compared to the cohesive sediments, which exhibited a wide range of growth rates, changes in water content and initial momentum of the non-cohesive particles produced 10 - 20 % variations in a. Material not incorporated into the cloud upon release formed a narrow "stem" behind the cloud, which contained as much as 30 % of the original mass depending on the release conditions. Much of the "stem" material either re-entrained into the cloud later in descent or reached the bottom shortly after it. Material not incorporated into the "stem," which may be advected by ambient currents, was found to be only a small fraction (< 1 %) of the original mass. Inverse integral model results suggest that CD and k are close to zero within the "thermal" phase. In the "circulating thermal" phase, the reduction in a caused by large particles (Nc > 10-4) increased k to a value similar to that of a solid sphere. Integral model results confirm the suitability of using constant coefficients for modeling particle clouds with Nc less than 10-. When Nc is greater than 10-4, time-varying a and k are required to properly simulate cloud behavior in the "circulating thermal" phase.
by Gordon J. Ruggaber.
Ph.D.
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Murray, Alexander J. "Modeling Artificial Groundwater Recharge in the Santa Rosa Creek Watershed." DigitalCommons@CalPoly, 2020. https://digitalcommons.calpoly.edu/theses/2140.
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The Santa Rosa Creek Watershed is an approximately 48 mi2 large watershed located on the central coast of California. This watershed drains to the Pacific Ocean through Santa Rosa Creek as it passes through agricultural land and the town of Cambria. Historically the groundwater within the Santa Rosa Creek Watershed has been used for irrigation, municipal and domestic uses, and the creek is critical habitat steelhead trout. During dry years, there is less water for all uses. When low groundwater levels occur, water can be drawn out of the creek and into the soil, drying out steelhead habitat. Seven agricultural operators within the Santa Rosa Creek Watershed are working with a local non-profit to improve sustainability of the aquifer through artificial groundwater recharge. One of these projects includes the use of a recharge basin. This study was conducted to understand the impacts of that recharge basin on the groundwater surrounding it as well as to evaluate the site’s potential for other recharge methods. The groundwater within the site of interest was modeled using GMS to calculate head values, to determine flow directions, and to determine timings. Three different hydrogeologic layers were used to simulate an upper unconfined zone, a clay confining layer, and a confined zone. The model was calibrated to known groundwater head values throughout the site. ArcMap was used to organize and preprocess data that went into the GMS model. Elevation, hydrologic soil characteristics, boundary heads, recharge rates, evapotranspiration rates, and well locations and pumping rates datasets were all preprocessed and imported into GMS. The model showed that the water from the recharge basin does not percolate into the underlying groundwater aquifer, but it flows out of the upper unconfined layer and into the creek over time. This is caused primarily by a low hydrologic conductivity confined aquifer in the northern section of the site as well as a confining clay layer underneath the unconfined top layer. According to the model, the site may not be feasible for artificial groundwater recharge in the northern portion, but there is potential for recharge in the southern area. Further data collection could improve the model to support or dispute these findings.
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Meyer, Thomas 1970. "Geologic stochastic modeling of rock fracture systems related to crustal faults." Thesis, Massachusetts Institute of Technology, 1999. http://hdl.handle.net/1721.1/9317.
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Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Civil and Environmental Engineering, 1999.Includes bibliographical references (p. 223-225).
In this study, the capabilities of the MIT three-dimensional geologic stochastic fracture model were extended so that fracture systems related to crustal faulting can be simulated. As presented here, the model comprises four stochastic processes: 1) a homogeneous, anisotropic Poisson process to model the orientation of the potential fracture planes according to an orientation distribution; 2) a homogeneous Poisson line process that tessellates the fracture planes and associates the polygons with fractured and intact rock; 3) a zone marking process that retains or discards the polygons according to their location in the modeling volume; 4) a process that translates and rotates the polygons from their original position in order to accommodate local geologic features. This research enhanced the capabilities of the model by introducing various ways of defining the zones in the zone marking process, and by developing new procedures to analyze the connectivity of the fracture systems. Two case studies of fracture systems generation were addressed. The first one discussed the formation of fault zones in igneous rock. It demonstrated that fracture sets with different properties can be generated in different, sharply defined zones of the same modeling volume. The second case analyzed the fracture systems in the bedrock underlying the Aberjona Valley. It showed that a correct treatment of field data could lead to reliable input parameters for the model, and therefore to reliable properties of the simulated fracture systems, in terms of fracture intensity, fracture size, fracture spacing along boreholes and fracture trace length on outcrops. Connectivity assessment of the simulated fracture systems in the bedrock underlying the Aberjona Valley was performed through analysis of the isolated clusters of interconnected fractures (fracture sub-networks). The horizontal extent of the largest sub-networks appeared to be limited to 9 meters in direction East-West and 11 meters in direction North-South, regardless of the size of the modeling volume. The extent in the vertical direction was not limited. The geometry of the sub-networks seems therefore to limit horizontal fracture flow over long distances, while providing significant storage capacity. Simulations of the fracture flow run with a finite element model developed at ETHZ confirmed the geometry of the phreatic surface as observed in field pumping tests. They also pointed out the role of large discontinuities in fracture flow and the need to model large volumes of rock to account for it.
by Thomas Meyer.
S.M.
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Lidelöw, Sofia. "Environmental assessment of construction with recycled materials." Doctoral thesis, Luleå, 2008. http://urn.kb.se/resolve?urn=urn:nbn:se:ltu:diva-26269.
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The use of industrial residues as raw materials in construction raises concerns over the potential leaching and dispersal of hazardous constituents from them into the environment. Their leaching behaviour has been studied in laboratory assays, but leaching processes in the field over larger spatial and temporal scales are more complex due to variations in the conditions the materials are exposed to, and less well understood. Hence, estimates of the potential environmental loads associated with the use of such materials based on laboratory tests may be inaccurate. This thesis addresses the environmental implications of using recycled materials in road and landfill cover constructions. The focus is primarily on the leaching of inorganic constituents from six types of materials: incineration ashes, copper smelter slag, blast-furnace slag, recycled concrete, natural rock and contaminated soil. The leaching behaviour of constituents from these materials were assessed in both laboratory batch leaching tests and monitoring programs in which the water percolating through them in field applications were sampled over one to ten years. Leaching data were evaluated using statistical and geochemical modelling. In addition, assessment methods and criteria to judge the environmental suitability of substituting natural materials for recycled materials in construction were reviewed. It was found that leachates from recycled materials in the constructions contain higher concentrations of several constituents than natural water and leachates from conventional materials. However, the rates and extent of constituent leaching were affected by the application methods in various ways that are explored and discussed. The results of simplified leaching tests did not always reflect the leaching behaviour in the field, which highlight the importance of developing assessment methods that allow case-specific factors to be taken into account. The environmental impacts of leaching must also be considered in relation to the expected impacts of the default alternative, i.e. landfilling of industrial residues and exploitation of natural resources. Combinations of case-specific assessments and system analyses would be the ideal approaches to evaluate impacts at both local and regional scales.Användningen av industriella restprodukter som konstruktionsmaterial inom anläggningsbyggande väcker frågan om möjlig utlakning och spridning av förorenande ämnen från materialen till omgivande miljö. Materialens lakningspotential bestäms vanligen genom lakförsök utförda under kontrollerade förhållanden i laboratorium. Lakningsprocesser i fält sker dock över större rums- och tidskalor och är mer komplexa på grund av variationer i miljön som materialen exponeras för. Uppskattningar av materialens möjliga miljöpåverkan baserade på laboratorietester kan därför vara felaktiga. Den här avhandlingen handlar om den miljömässiga betydelsen av att använda återvunna material som konstruktionsmaterial i vägar och deponisluttäckningar. Fokus är i huvudsak på utlakningen av oorganiska ämnen från sex typer av material: förbränningsaskor, kopparslagg, hyttsten, återvunnen betong, naturligt berg och förorenad jord. Utlakningen från dessa material undersöktes med hjälp av både skakförsök i laboratorium och kontrollprogram där vatten som perkolerade materialen i fältapplikationer (sk. lakvatten) provtogs under ett till tio år. Lakvattendata utvärderades med hjälp av statistisk och geokemisk modellering. Dessutom granskades olika bedömningsmetoder och kriterier som kan användas för att bedöma den miljömässiga lämpligheten av att använda återvunna istället för naturliga material i anläggningskonstruktioner. Lakvatten från återvunna material i de undersökta konstruktionerna innehöll högre koncentrationer av flera ämnen än naturliga vatten och lakvatten från naturliga material. Dock var hastigheten och omfattningen av utlakningen beroende av hur materialet användes, vilket har undersökts och diskuteras i avhandlingen. Resultaten från förenklade skakförsök överensstämde inte alltid med observationerna i fält, vilket understryker vikten av att utveckla bedömningsmetoder där fallspecifika faktorer kan tas i beaktande. Miljöpåverkan orsakad av lakning måste också ses i relation till den påverkan som kan uppstå om restprodukterna istället deponeras och naturliga material exploateras. Kombinationer av fallspecifika och systemövergripande analyser skulle därför vara det ideala sättet att utvärdera både lokala och regionala effekter av en möjlig användning av återvunna material.
Godkänd; 2008; 20081003 (ysko)
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Annie, Lundberg. "Environmental transformations of Manganese and Manganese oxide nanoparticles." Thesis, KTH, Materialvetenskap, 2020. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-289637.
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Engineered nanoparticles (NPs) are produced in increased quantities. Due to this increase, itis vital to understand the full lifecycle and fate of these NPs to prevent any possible environmental stress. As a result of their size, NPs may interact differently with their environment compared to bulk materials with the same composition, this both gives NPs their usage as well as risks. The risks often include unwanted interaction with biological systems which may lead to generation of toxicity. This study focused on environmental transformations of manganese and manganese oxide (Mn3O4) NPs. Applications these nanoparticles are often in battery technology and catalysis. A solution intended to mimic the composition of freshwater was used as the environmental media to study these transformations. Exposure of NPs was performed both with and without added natural organic matter (NOM). Several experiments were preformed such as Atomic absorption spectroscopy (AAS) for dissolution of the NPs, Nanoparticle Tracking Analysis (NTA) for particle size, and Attenuated total reflection Fourier transform infrared spectroscopy (ATR- FTIR) for adsorption studies. The production of reactive oxygen species (ROS) was also investigated, and simulations of metal speciation using Visual MINTEQ were also performed. The results from NTA and AAS (for Mn3O4) were not very reliable due to inconsistencies in the results which were probably caused by problems with preparation. However, for both, the results point towards that the dissolution rates of the particles are slightly slowed down when NOM is added. From ATR-FTIR and the simulations it was confirmed that NOM, carbonate, and sulfur will adsorb onto both particles, possibly in multiple layers. As for increased ROS development, no evidence of such an increase was found. However, the method used does not test for increased hydrogen peroxide development so this would in interesting test as well. Other studies which also would contribute to a more nuanced picture of this system is studies regarding zeta potential and studies which furtherinvestigates the type of adsorption mechanism which occurs at the particles surface.Industriella nanopartiklar används i allt större utsträckning. Därför är det av stor vikt attundersöka hela livscykeln som dessa produkter går igenom for att säkerhetsställa att de inte utgör någon fara för miljön och ekosystemen som de kan komma att hamna i. Som ett resultat av deras storlek interagerar nanopartiklar annorlunda med sin omgivning om man jämför med bulkmaterial av samma sammansättning, detta nanopartiklar både sina unika fördelar och risker. Riskerna innefattar ofta oönskade interaktioner med biologiska kretslopp som kan resultera i toxicitet. I den här rapporten läggs fokus på just denna typ av kemiska omvandlingar som nanopartiklar av mangan och manganoxid kan tänkas genomgå i det naturliga kretsloppet. Applikationer man ofta ser dessa partiklar i är batteriteknologi och katalys. De medium som används för att studera omvandlingarna är en lösning som efterliknar ytvatten från en klar sjö. Exponeringar gjordes både med denna lösning så som den är och med tillsatt naturligt organiskt material, NOM.En rad olika experiment gjordes så som analyser med AAS för att undersöka partiklarnas upplösning, NTA för partikelstorlekar och ATR-FTIR som undersökte adsorption på partiklarna. Även en studie med en DCFH metod där ökat ROS aktivitet undersöktes och en rad med SHM simuleringar gjorda i Visual MINTEQ utfördes. Resultaten från NTA och AAS analysen visade sig inte vara särskilt tillförlitliga på grund av tvetydliga resultat som troligen orsakats av problem med provpreparationen. Men resultaten från båda dessa pekar mot att upplösningshastigheten blir något hämmad då man tillsätter naturligt organiskt material, för båda partiklarna. Från ART-FTIR och simuleringarna kunde de säkerhetsställas att adsorption av NOM, karbonat och svavel sker på båda partiklarna, möjligen i fler än ett lager. När det kommer till ROS studien kunde inga bevis på ökad ROS aktivitet hittas med den använda metoden. Dock så kunde inte ökat väteperoxid aktivitet mätas med den metod som användes så detta hade varit av intresse att testa i framtiden. Andra studier som också skulle vara hjälpsamma för att ge en mer nyanserad bild av detta system är en studie om partiklarnas zeta potential och merundersökningar om vilken typ av adsorptions mekanism som sker vid partiklarnas yta.
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Rocha, Andrea M. "Computational Discovery of Phenotype Related Biochemical Processes for Engineering." Scholar Commons, 2011. http://scholarcommons.usf.edu/etd/3315.
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Application of bioengineering technologies for enhanced biological hydrogen production is a promising approach that may play a vital role in sustainable energy. Due to the ability of several naturally occurring microorganisms to generate hydrogen through varying metabolic processes, biological hydrogen has become an attractive alternative energy and fuel source.
One area of particular interest is the production of biological hydrogen in organically-rich engineered systems, such as those associated with waste treatment. Despite the potential for high energy yields, hydrogen yields generated by bacteria in waste systems are often limited due to a focus on microbial utilization of organic material towards cellular growth rather than production of biogas. To address this concern and to improve upon current technological applications, metabolic engineering approaches may be applied to known hydrogen producing organisms. However, to successfully modify metabolic pathways, full understanding of metabolic networks involved in expression of microbial traits in hydrogen producing organisms is necessary.
Because microbial communities associated with hydrogen production are capable of exhibiting a number of phenotypes, attempts to apply metabolic engineering concepts have been restricted due to limited information regarding complex metabolic processes and regulatory networks involved in expression of microbial traits associated with biohydrogen production.
To bridge this gap, this dissertation focuses on identification of phenotype-related biochemical processes within sets of phenotype-expressing organisms. Specifically, through co-development and application of evolutionary genome-scale phenotype-centric comparative network analysis tools, metabolic and cellular components related to three phenotypes (i.e., dark fermentative, hydrogen production and acid tolerance) were identified. The computational tools employed for the systematic elucidation of key phenotype-related genes and subsystems consisted of two complementary methods. The first method, the Network Instance-Based Biased Subgraph Search (NIBBS) algorithm, identified phenotype-related metabolic genes and subsystems through comparative analysis of multiple genome-scale metabolic networks. The second method was the multiple alignments of metabolic pathways for identification of conserved metabolic sub-systems in small sets of phenotype-expressing microorganisms. For both methodologies, key metabolic genes and sub-systems that are likely to be related to hydrogen production and acid-tolerance were identified and hypotheses regarding their role in phenotype expression were generated. In addition, analysis of hydrogen producing enzymes generated by NIBBS revealed the potential interplay, or cross-talk, between metabolic pathways.
To identify phenotype-related subnetworks, three complementary approaches were applied to individual, and sets of phenotype-expressing microorganisms. In the first method, the Dense ENriched Subgraph Enumeration (DENSE) algorithm, partial "prior knowledge" about the proteins involved in phenotype-related processes are utilized to identify dense, enriched sets of known phenotype-related proteins in Clostridium acetobutylicum. The second approach utilized a bi-clustering algorithm to identify phenotype-related functional association modules associated with metabolic controls of phenotype-related pathways. Last, through comparison of hundreds of genome-scale networks of functionally associated proteins, the á, â-motifs approach, was applied to identify phenotype-related subsystems.
Application of methodologies for identification of subnetworks resulted in detection of regulatory proteins, transporters, and signaling proteins predicted to be related to phenotype-expression. Through analysis of protein interactions, clues to the functional roles and associations of previously uncharacterized proteins were identified (DENSE) and hypotheses regarding potentially important acid-tolerant mechanisms were generated (á, â-motifs). Similar to the NIBBS algorithm, analysis of functional modules predicted by the bi-clustering algorithm suggest cross-talk is occurring between pathways associated with hydrogen production.
The ability of these phenotype-centric comparative network analysis tools to identify both known and potentially new biochemical process is important for providing further understanding and insights into metabolic networks and system controls involved in the expression of microbial traits. In particular, identification of phenotype-related metabolic components through a systems approach provides the underlying foundation for the development of improved bioengineering technologies and experimental design for enhanced biological hydrogen production.
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Ras, Cornelia. "An industrial ecology approach to salt-related environmental sustainability issues in a large industrial complex." Master's thesis, University of Cape Town, 2011. http://hdl.handle.net/11427/10737.
Full textAbstract:
Includes sysnopsis.Includes bibliographical references (p.93-106).
This thesis aims to demonstrate the application of industrial ecology (IE) theory to understand environmental sustainability problems relating to the accumulation of saline wastes and to study the potential for integrated technology interventions which take multi-party engagements and effects into account.
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Armstrong, Robert James 1970. "Evaluation of the accessibility effects and proximity related externalities of commuter rail service." Thesis, Massachusetts Institute of Technology, 1997. http://hdl.handle.net/1721.1/43520.
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Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Civil and Environmental Engineering, 1997.Includes bibliographical references (p. 254-275).
by Robert James Armstrong, Jr.
M.S.
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Woertz, Ian C. "Lipid Productivity of Algae Grown on Dairy Wastewater as a Possible Feedstock for Biodiesel." DigitalCommons@CalPoly, 2008. https://digitalcommons.calpoly.edu/theses/183.
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The objective of this thesis is to develop a biological wastewater treatment system that utilizes algal growth to simultaneously create renewable energy in the form of biodiesel and digester biogas, remove polluting nutrients, and abate greenhouse gases. Research under the Department of Energy Aquatic Species Program during 1978-1996 concluded that cultivating algae for biofuels was cost prohibitive at that time and that an integrated approach should be studied that combined wastewater treatment with algal biofuel production. Nutrient removal, in particular nitrogen and phosphorus, from wastewater is a growing regulatory need and the use of algae cultivation could create a unique marriage between waste treatment and biofuel production. To investigate this possible synergy, bench-scale tests were conducted to determine potential algal lipid productivity with mixed-cultures of algae grown on anaerobically-pretreated dairy wastewater in batch mode. The total lipid content of the algae ranged from 8% to 29% of algal mass. Maximum biomass concentration reached 920 mg/L, measured as volatile suspended solids, on Day 13 of incubation. In contrast, maximum total lipid content was reached at Day 6, corresponding to a lipid productivity of 2.8 g/m^2/day, or 1,200 gallons/acre/year if scaled up. Nutrient removal over 12 days of incubation was nearly complete. Total ammonia (NH3+NH4+) was reduced 96% to 1.1 mg/L as N, and phosphate (PO4^3-) was reduced >99% from an initial concentration of 2.5 mg/L PO4 as P.
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Tham, Yieng Wei. "Solar radiation related climate change projections for the UK." Thesis, Edinburgh Napier University, 2011. http://researchrepository.napier.ac.uk/Output/4577.
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This research is mainly focussed on solar radiation in the UK. It can be divided into four main areas; evaluation of models, analysis of the relations between temperature and solar radiation, critical analysis of the projected future data for the UK and the improvement to the UKCP09 Weather Generator (WG). From the evaluations of models carried out, the Liu-Jordan model performs well for estimating the average hourly global and diffuse radiation. At the individual hourly level however, a number of problems were observed. Regarding clear- sky radiation models, for semi-arid climatic conditions Page model was found to be suitable and for humid climates Yang model is recommended. As for all-sky radiation models, the MRM and Yang model were selected. For the UK, the MRM was found to perform better than the Yang model. Furthermore, a study was carried out to analyse the relationship between temperature and solar radiation. The development of temperature-based mathematical models to obtain mean-daily irradiation was established. A procedure to decompose daily to hourly temperatures was evaluated with respect to world-wide locations and its performance found to be satisfactory. As part of the UKCP09/COPSE project, detailed analysis on the future projected data was carried out to critically evaluate sol-air temperature and the likely change that may occur in the key climatic variables, i.e. temperature, sunshine duration and solar irradiation. Drastic increase of sol-air temperatures and shifting trend of daylight illuminance were found. Furthermore, a sensitivity test was also carried out to analyse the effects of each input variables on sol-air temperature. As a result of the present investigations and communications with the UKCP personnel a new version of WG was released with appropriate modifications. A comparison of the now old- and new WG data sets has been made. Improvements in ratio of diffuse to global radiation and sunshine datasets were found.
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Tasala, Gradin Katja. "The importance of system boundaries for environmental assessment of vehicles." Licentiate thesis, KTH, Maskinkonstruktion (Avd.), 2016. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-194437.
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Vehicles are generally viewed as having their major environmental impact in the use phase because of combustion emissions. New technology can significantly decrease use emissions. These advantages suggest a rise in alternative vehicle drivetrains, e.g. electrical motors as well as a decrease of fossil fuel engines. It is of importance to consider what impact this technical shift might have in a lifecycle perspective. New technology requires specialised materials which in turn have substantial impacts during raw material extraction, manufacturing, and end of life. This means that the utilised materials may affect the total life cycle impact of a product. The impact can shift to other life phases and additionally give rise to impacts other than the frequently used energy consumption and climate change. The aim of this thesis is to understand how system boundaries effect environmental impact assessment. Potential life cycle assessment issues are investigated through studies of vehicle environmental impacts in different lifecycle phases and varying system boundaries. These issues are approached through several tools: LCA, Environmentally Responsible Product Assessment (ERPA), and Material Hygiene (MH). Three publications are appended to this thesis. Publication A compares two different disposal scenarios for end of life vehicles in Sweden. Publication B compares complete life cycle impacts of two dissimilar drivetrains in similar vehicles. Publication C investigates potential benefits of a concept sea vessel by comparing it with cargo transport by trucks. To fairly compare vehicles, with different drivetrain technology, it is not advisable to apply assessment that is limited to studying the use phase. Neither is it reliable to limit impact inventory to only energy use and CO2 emissions. The consequences of a narrow system-boarder are difficult to keep track of. To avoid sub-optimising and minimise risk of unawareness of trade-offs life cycle perspective is essential.QC 20161116
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Larsson, Dan. "A study of the track degradation process related to changes in railway traffic." Licentiate thesis, Luleå, 2004. http://epubl.luth.se/1402-1757/2004/048.
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Nilsson, Mirja. "Environmental assessment of bottom ash pre-treated with zero valent iron." Licentiate thesis, Luleå tekniska universitet, Geovetenskap och miljöteknik, 2014. http://urn.kb.se/resolve?urn=urn:nbn:se:ltu:diva-16832.
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Bottom ash has similar properties as crushed rocks and gravel, andcould replace some of the 40 million tonnesof virgin material used for road constructions each year.However, results presented in the literature indicate thatthe leaching of e.g. Cr, Cu, Mo, Pb and Zn can cause athreat to the sur rounding environment if the materialis used as it is. A common pre-treatment method is carbonation, whichwill reduce the pH and thereby decrease the leaching of several metals. This treatment is however not always enough, so alternative methods areneeded. One possibility could be to increase the number of sorption sites for the metals. The importance of iron oxides as sorption sits for metals isknown from both mineralogical studies of bottom ash as well as from theremediation of contaminated soil, where iron is used as an amendment.Zero valent iron (Fe 0) was therefore added prior to accelerated agingin order to increase the number of adsorption sites for metals and thereby improving the leaching quality. The performed leaching tests showed that theaddition of Fe 0 prior to accelerated aging improved the quality of the leachate compared with untreated bottom ash. There was also a significant de crease of Cu, Cr, Mo and Zn from bottom ash treated with Fe0 prior to accelerated aging com pared with bottom ash submitted to only accelerated aging. In order to make an environmental assessment of the bottom ash pretreated with Fe 0 prior to accelerated aginggeochemical modeling was performed using different pH and redox potentialsin order to simulate variations in the environment.The results in dicated that the leaching of Cr, Cr, Mo and Pb would not cause harm to the environment.Zn, however, was affected by changes in pH and leached in harmful aounts at pH values velow 6 and above 10.There are reasons to question the results from the geochemical modellingsince the results from pH-stat tests showedthat several elements leached at potentially harmful levelsat several of the tested pH. To fully evaluate the effect of addition of Fe0should the mineralogy of the pretreated bottom ash be evaluated further, in order to see what forms iron oxides are pre sent and if other metals are associated with them. However, in order to improve the quality of bottom ash,focus should be directed torwards what type of wastes that areincinerated and on the incineration process.Godkänd; 2014; 20141110 (mirnil); Nedanstående person kommer att hålla licentiatseminarium för avläggande av teknologie licentiatexamen. Namn: Mirja Nilsson Ämne: Avfallsteknik/Waste Science and Technology Uppsats: Environmental Assessment of Bottom Ash Pre-Treated with Zero Valent Iron Examinator: Professor Anders Lagerkvist, Institutionen för samhällsbyggnad och naturresurser, Luleå tekniska universitet Diskutant: Tekn Dr Josef Mácsik, Ecoloop, Stockholm Tid: Onsdag den 17 december 2014 kl 13,00 Plats: Rum F1030, Luleå tekniska universitet
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He, He S. M. Massachusetts Institute of Technology. "Representing accessibility in long-term household decisions evidence from vehicle ownership and residential location-related choice models." Thesis, Massachusetts Institute of Technology, 2018. http://hdl.handle.net/1721.1/120646.
Full textAbstract:
Thesis: S.M. in Transportation, Massachusetts Institute of Technology, Department of Civil and Environmental Engineering, 2018.Cataloged from PDF version of thesis.
Includes bibliographical references (pages 80-83).
This study examines variations in representing accessibility and how well these representations reflect people's preferences for accessibility as observed in their behaviour in long-term transportation and location-related decisions. Specifically, we estimate household vehicle ownership models and real estate market price models with different measures of accessibility. Better performing accessibility measures are better representations of accessibility - at least for the purposes of explaining the modelled behaviour. We compare gravity-based accessibility, an aggregate measure of potential; trip-based accessibility, a disaggregate measure of utility; and activity-based accessibility, a disaggregate measure of utility that also captures the effect of individuals' activity schedules. We find that (1) disaggregate accessibility perform better in explaining disaggregate (e.g. household-level) behaviour; (2) although measures of potential can be useful as performance indicators, people and market behaviour are better explained by measures of utility; and (3) the current formulation of the activity-based accessibility measure performs no better than the trip-based measure, likely due to imperfections in its operationalization in the relevant models, e.g., inadequate in its representation of activity schedule effects.. We then examine activity-based accessibility in more detail. In particular, we consider different interpretations by changing its benchmark, i.e. the hypothetical scenario relative to which benefits are measured. Furthermore, we examine the effects of measuring accessibility in units of time or money instead of utility. For benchmarks, we find that using a "no out-of-home activity participation"-scenario appears most appropriate. For rescaling, the most appropriate unit of measure depends on the explained behaviour. For example, for explaining the market price of real estate, which itself is measured in dollars, dollar-scaled accessibility performed best. The overall takeaway from these tests is that a single "best" measure of accessibility does not necessarily exist; different measures have their own advantages and limitations vis-à-vis theoretical appeal, data requirements, communicability, etc. What is imperative is that we understand what each measure actually captures and that this aligns with the purpose for which we use it. Finally, we examine the limitations of the estimation of the real estate willingness-to-pay function in SimMobility's bidding model, and propose an alternative estimation method.
by He He.
S.M. in Transportation
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Little, Patrick. "Improving railroad freight car reliability using a new opportunistic maintenance heuristic and other information system improvements." Thesis, Massachusetts Institute of Technology, 1991. http://hdl.handle.net/1721.1/41775.
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Möller, Clemens. "Carbon Neutral Road Transportation : An Assessment of the Potential of Electrified Road Systems." Thesis, KTH, Industriell ekologi, 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-211094.
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Sweden is striving towards a carbon neutral transportation sector by2030 which includes reductions from CO2 emissions by 70%. This thesis focusses especially on the decarbonization of road freight transportation. Even though electrification of vehicles is seen as one of the available options to reach this goal, present battery technology does not meet requirementsof energy density and cost. The electrification of roads with electrified road systems (ERS) enables vehicles to charge electrical energy while in motion and has the potential toreduce weight and costs of on-board batteries for electric vehicles and avoids range anxiety of vehicle operators. Within this Master’s thesis, available ERSs are assessed and it is shown which of the available systems performs best in selected categories. Furthermore, alterantive options for large CO2 emission reductions in the roadtransportation sector are evaluated and it is shown that ERSs constitute the most promising alternative. Results of this dissertation are based on a qualitative research approachand limited to data availability.
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Dahlén, Lisa. "Household waste collection : factors and variations." Doctoral thesis, Luleå tekniska universitet, Geovetenskap och miljöteknik, 2008. http://urn.kb.se/resolve?urn=urn:nbn:se:ltu:diva-16955.
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Ambitious household waste recycling programs have been introduced in Sweden and several other countries during recent decades. Many different waste- sorting and collection schemes have been developed, but the evaluation and comparison of the results is made difficult by the lack of comparable data. The aim of the research presented in this thesis was to answer the following questions: How can household waste flows be described and monitored? Which factors affect the collection results? and, What is a useful basis for the evaluation of collection systems? Waste flow analysis and waste component classification were performed in a number of Swedish municipalities, revealing a wide variation in the amount of waste per capita. Eleven site-specific variables were investigated and multivariate data analysis was performed. The study was carried out on three levels: 1) household waste as the material in itself, classified into physical components, 2) the householders and their handling of waste, in terms of average amounts of different waste categories and recyclables per capita, and 3) the municipalities, as the authority responsible for household waste management, where local conditions influence waste generation and pathways. A significant finding was that property-close collection of dry recyclables led to increased collection of sorted metal, plastic, and paper packaging. Weight-based billing, i.e. when waste collection is charged per kilogram of waste collected, showed divergent effects, which are investigated and discussed. Monitoring methods are suggested regarding the waste flow from households. A step-by-step method for evaluation and comparisons of collection systems was outlined, including a set of indicators. Sixteen sources of error in official waste statistics were identified and the results of the studies emphasize the importance of reliable waste generation and composition data to underpin waste management policies.Ambitiösa återvinningssystem för hushållsavfall har införts i Sverige, och i många andra länder, under de senaste årtiondena. Många olika system för källsortering och insamling har utvecklats, men utvärdering och jämförelse av insamlingsresultat försvåras av bristen på jämförbara data. Följande frågor diskuteras och besvaras i avhandlingen: Hur kan avfallsflödet från hushåll mätas och undersökas? Vilka faktorer påverkar avfallsflödet från hushållen? Hur kan olika insamlingssystem göras jämförbara och utvärderas? Studien utfördes på tre nivåer:(1) hushållsavfallet, klassificerat i olika material och komponenter, (2) hushållen och deras hantering av hushållsavfallet, och (3) kommunerna, i egenskap av ansvarig myndighet för hantering av hushållsavfall, där förutsättningarna påverkas avlokala faktorer. Avfallsflödesanalyser, inklusive plockanalys av hushållsavfall, har genomförts i ett antal svenska kommuner, vilket visade stora variationer i avfallsmängder per person. Elva faktorer, som antogs påverka avfallsflödet, undersöktes och multivariat dataanalys tillämpades. Studien visar bland annat att kommuner med fastighetsnära insamling av återvinningsmaterial samlade in mer metall-, plast- och pappersförpackningar per person, jämfört med kommuner som bara hade återvinningsstationer för insamling av förpackningar. Viktbaserad avfallstaxa, dvs när hämtning av hushållsavfall faktureras per kg avfall som finns i kärlet, har visat sig ge varierande effekter i olika kommuner, vilket har undersökts och diskuterats. I genomsnitt var mängden osorterat hushållsavfall 20 % mindre per person i kommuner med viktbaserad taxa, jämfört med övriga landet. Någon skillnad i mängden källsorterade återvinningsmaterial kunde dock inte påvisas. Mätmetoder för hushållsavfallsflödet föreslås, tillsammans med en steg-för-steg utvärderingsmetod för jämförelse av olika insamlingssystem, innefattande en uppsättning nyckeltal. Sexton felkällor har identifierats i officiella avfallsdata och en slutsats av studien är att det i dagsläget saknas tillförlitliga data som beslutsunderlag för utveckling av avfallshantering och avfallspolicy.
Godkänd; 2008; 20080602 (ysko)
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Kumpiene, Jurate. "Role of soil organic matter for immobilisation of metals : treatment of leachate from MSWI bottom ashes." Licentiate thesis, Luleå tekniska universitet, Geovetenskap och miljöteknik, 2003. http://urn.kb.se/resolve?urn=urn:nbn:se:ltu:diva-16842.
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In this thesis, the focus is laid on the ability of natural organic matter (OM) to serve as a metal stabilising agent. The metal contaminants investigated arise from the MSWI bottom ash leachate. Besides the high content of metals, elevated pH and salinity are characteristic for ash leachate that, in turn, can alter the functionality of OM. Batch and column leaching tests were used to study the retention capacity of substrates with different amount of OM. Also, field observations were made of the influence of ash leachate on soil and plants. In this case, ash leachate was generated under field conditions from an experimental road built on municipal solid waste incineration (MSWI) bottom ashes. It has been shown that copper, chromium, and lead retention is proportional to OM content of the substrates. Zinc retention showed to have the least dependence on OM. The metals were not leached in proportion to dissolved OM. Most probably several mechanisms were responsible for the retention of metals: (i) high concentration of Ca in ash leachate could lead to the formation of Ca-dissolved organic carbon (DOC) complexes that have the ability to precipitate some metals (ionic strength effect) and prevent metal transport; (ii) high solution pH could favour hydroxide formation and counteract the metal complexation with dissolved OM, as well as (iii) surface adsorption could contribute to metal retention. Despite the good metal retention capacity of OM, a continuous metal load will occupy binding sites of OM and therefore reduce its retention capacity. Metal retention capacity of rich in OM substrate could be improved by additional soil amendments and vegetation. Tolerant plant species that are capable to grow at high soil metal concentrations and immobilize pollutants within the root zone have a potential to be used for phytostabilisation of metal contaminated soil. Such plants are also associated with a low risk of the translocation of contaminants from soil through plant roots to shoots, i.e. from one media to another. Immobilization is not a technology for the removal of contaminants from soil but for the stabilization (inactivation) of potentially toxic metals. The aim of soil remediation is to reduce the contaminant exposure and spread. Then the reduced leaching, bioavailability, as well as ecotoxicity of metals as a result of phytostabilisation might be a proper solution. Development of suitable soil and amendment mixtures capable to retain broad range of metals and interaction of plants with stabilised matrix are the questions to be answered in the future research.Godkänd; 2003; 20070109 (mlk)
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Maurice, Christian. "Landfill gas emission and landfill vegetation." Licentiate thesis, Luleå tekniska universitet, Geovetenskap och miljöteknik, 1998. http://urn.kb.se/resolve?urn=urn:nbn:se:ltu:diva-17271.
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Todorovic, Jelena. "Diffusion tests for assessing leaching from incineration residues." Licentiate thesis, Luleå, 2004. http://urn.kb.se/resolve?urn=urn:nbn:se:ltu:diva-26593.
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Increasing amounts of incineration residues need to be disposed, reused or treated, which calls for reliable characterisation methods. Leaching tests are often used for an assessment of release of pollutants from wastes under a variety of leaching factors. Nevertheless, the prediction of the contaminants release in field is difficult due to the complexity of the processes occurring in field. This work aims at evaluating limitations and possibilities of making long- term leaching predictions for incineration residues using diffusion leaching tests. Also the effect of carbonation on the leaching of elements was evaluated. Leaching predictions for Cl and Pb based on diffusion test data were compared with leachate data from MSWI bottom ash reused in road construction as well as leachate data obtained using a two-step compliance test. For the first years, leaching of Cl from bottom ash in field could be predicted with an accuracy within one order of magnitude. This could be considered as a good fit. Good agreement was also found between leaching predictions based on the diffusion test and the compliance test for Pb. However, predictions based on a diffusion tests might be misleading for longer time periods as the stock of contaminants depletes. Longer time series of field data are needed for comparison. Field conditions such as wet/dry and freezing/thawing cycles were not considered in this work, but might affect the mobility of contaminants. The impact of such field factors deserves a thorough examination in future research. Carbonation was found to significantly affect leaching of some elements from MSWI bottom ash. Leaching of Pb and Zn was increased due to carbonation, while leaching of Cr, Mo, and Sb decreased. Leaching of Cu was increased by carbonation alone, but it was also observed that leaching could be decreased if carbonation is combined with water-solidification. With such effect on leaching it is necessary to take carbonation into account when leaching predictions are made.Godkänd; 2004; 20070127 (ysko)
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Diener, Silvia. "Ageing behaviour of steel slags in landfill liners." Licentiate thesis, Luleå tekniska universitet, Geovetenskap och miljöteknik, 2009. http://urn.kb.se/resolve?urn=urn:nbn:se:ltu:diva-26542.
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Steel slags are by-products of the steelmaking process. To avoid unnecessary disposal, e.g. into landfill, their chemical and physical properties should be exploited to support alternative uses. Steel slags can be recycled within the steel plant or used as construction material in roads, hydraulic engineering and different types of barriers, including landfill covers. A landfill cover consists of several layers, including a liner with low water and gas permeability in order to reduce methane and leachate emissions. Several studies have demonstrated that steel slags have good potential to fulfil such an application. However, there are questions regarding the stability of the slag minerals over long periods of time. A landfill cover must function well for many decades and centuries. In order to predict the long-term stability of steel slags as a landfill liner, laboratory experiments have been performed to study the effects of accelerated ageing of steel slag under controlled conditions. The factors investigated in the storage atmosphere were carbon dioxide content, relative humidity and temperature. The influence of leachate contact and ageing time were also assessed.This thesis reports the study of electric arc furnace slags and ladle slag from the production of high-alloyed tool steel after accelerated ageing for periods of three months and ten months. Mineralogy and leaching were studied using two different leaching tests, thermal analysis, acid-neutralization capacity assays and X-ray diffraction. For the ageing periods considered, the exposure of the slags to an atmosphere enriched with carbon dioxide had the greatest impact on leaching. In general, calcium, aluminium, sulphur and sodium leached from the slag matrix to the greatest extent while other metals such as chromium, nickel, lead and zinc were found at very low levels in the leachate. The leaching of calcium and aluminium reduced with increasing carbon dioxide level. Thermal analysis revealed the decomposition of carbonates. Weight and enthalpy changes were evaluated between 100 and 1000 °C. The buffer capacity of the steel slags, represented by the acid neutralization capacity (ANC 4.5) was not reduced after 10 months of ageing. However, the division of the titration into two steps revealed a shift of buffering zones for more highly aged samples, probably due to the formation of carbonates. The mineralogy of the investigated steel slags was complex with a large variety of mineral phases, principally calcium silicates, monticellite, periclase and a spinel phase. Other possible phases were gehlenite, merwinite, akermanite and iron. The existence of different solid solution is likely among the slag phases and can cause shifting of peaks in the X-ray diffractogram. Also, calcite was identified. Short-term carbonation has not shown significant impact on mineralogy despite of calcite formation. The results of the study contribute to a better understanding of the chemical and mineral stability of electric arc furnace slag and ladle slag in the environment of a landfill liner. The consequences of slag ageing include reduced leaching rates for certain elements. To predict the long-term behaviour of aged slag, the results of this study should be combined with data from two other sources - an ongoing ageing experiment that includes mechanical tests and a full scale field test at the Hagfors landfill. Additional analytical methods that can better characterise the mineralogy, for example scanning electron microscopy (SEM) and energydispersive X-ray spectroscopy (EDX), should also be applied to better quantify the mineralogical phases and to determine which trace elements are most abundant in specific minerals.Stålslagg är en restprodukt som kommer från ståltillverkningen. Den har kemiska och fysikaliska egenskaper som bör utnyttjas och som gör den lämplig för återanvändning, samtidigt som onödig deponering kan undvikas. Stålslagg kan återanvändas inom ståltillverkningen eller så kan den användas som konstruktionsmaterial i väg- och vattenbyggnadskonstruktioner eller i olika typer av barriärkonstruktioner som till exempel deponisluttäckningar. En deponisluttäckning består av flera skikt där tätskiktet ska ha en låg vatten- och gaspermeabilitet för att minska metan- och lakvattenutsläpp. Flera studier visar att stålslagg uppfyller dessa egenskaper och har potential att kunna användas i deponitäckning. Men det finns fortfarande oklarheter angående slaggmineralernas stabilitet över en längre tid. En deponitäcknings funktion förväntas vara stabil i många tiotals eller hundratals år. För att kunna förutsäga det långsiktiga beteendet för stålslagg i ett tätskikt genomfördes ett laboratorieexperiment vars syfte var att studera effekterna av accelererad åldring under kontrollerade förhållanden. De faktorer som studerades var koldioxidhalten, relativa luftfuktigheten, temperaturen, kontakten med lakvatten samt åldringstiden. I denna avhandling presenteras undersökningen av ljusbågsugnsslagg och skänkslagg, från framställning av höglegerat verktygsstål, efter tre respektive tio månaders accelererad åldring. Mineralogin och lakningsegenskaperna studerades genom två typer av laktester, termiska analyser, analys av syraneutraliserande kapacitet samt röntgendiffraktion. För de studerade åldringstiderna var det exponeringen av stålslaggen för en koldioxidrik atmosfär som hade den största inverkan på lakningsegenskaperna. Kalcium, aluminium, svavel och natrium var de ämnen som uppvisade den högsta utlakningen från slaggen medan metaller som krom, nickel, bly och zink endast fanns i väldigt låga koncentrationer i lakvattnet. Utlakningen av kalcium och aluminium minskade med en ökande halt av koldioxid. Termiska analyser visade på en nedbrytning av karbonater. Vikt- och entalpiförändringar mellan 100 och 1000°C utvärderades. Stålslaggens buffertkapacitet, representerad av den syraneutraliserande kapaciteten (ANC pH 4,5), reducerades inte efter tio månaders åldrande. Däremot visade uppdelningen av titreringen i två steg på en förskjutning av buffertområdena för de prover som åldrats tio månader, förmodligen på grund av karbonatbildning. Mineralogin för de undersökta stålslaggerna var komplex med en stor variation av mineralfaser, främst kalciumsilikater, monticellit, periklas och en spinellfas. Andra möjliga mineralfaser var gehlenit, merwinit, åkermanit och järn. Förekomsten av olika fastfaslösningar i stålslaggsmineralerna är sannolik vilket kan orsaka förskjutningar av topparna i diffraktogrammen. Kalcit identifierades också. Karbonatisering under en kort tid visade sig inte ha någon signifikant inverkan på mineralogin, förutom en viss kalcitbildning. Resultaten från studien bidrar till en bättre förståelse av stabiliteten för ljusbågsugns- och skänkslagg i den miljö som finns i ett tätskikt. Åldringen av slaggen resulterade i en reducerad utlakning av vissa element. För att kunna förutsäga det långsiktiga beteendet för åldrad slagg bör resultaten från den här studien kombineras med data från ett pågående åldringsförsök som inkluderar mekaniska tester samt ett fullskaligt fältförsök på Hagfors deponi. Analysmetoder som mer detaljerat kan karaktärisera mineralogin, till exempel svepelektronmikroskopi (SEM) och energidispersiv röntgenspektroskopi (EDX), bör också användas för att bättre kunna kvantifiera mineralfaserna och bestämma vilka spårelement som är vanligast i specifika mineraler.
Godkänd; 2009; 20090320 (sildie); LICENTIATSEMINARIUM Ämnesområde: Avfallsteknik Examinator: Professor Anders Lagerkvist, Luleå tekniska universitet Tid: Fredag den 24 april 2009 kl 14.15 Plats: F 664f, Luleå tekniska universitet
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Svensson, Malin. "Controlling the mobility of organic carbon (OC) ant its impact on metal transport from incineration residues." Licentiate thesis, Luleå tekniska universitet, Geovetenskap och miljöteknik, 2006. http://urn.kb.se/resolve?urn=urn:nbn:se:ltu:diva-17347.
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Incineration residues contain both inorganic and organic material. The organic material may affect the mobility of pollutants in e.g. landfills or geotechnical constructions. Limit values of TOC (total organic carbon), determined according to European standard are stipulated to reduce the disposal of organic materials. The European standard methods to determine TOC and DOC (dissolved organic carbon) are evaluated. Factors controlling the mobility of DOC and its effect on metal mobility have also been studied. Determination of TOC according to European standard methods EN 13 137 and EN 1 484 include those carbon fractions that are oxidized during combustion. The definition of TOC as total organic carbon is not equivalent with the analytical result. The European standards on the definition of TOC need revision. Both organic and elemental carbon are oxidized upon heating, and the analytical TOC is thus a sum of organic and elemental carbon present in the sample. Since elemental carbon comprise the major part of the analytical TOC in solid samples of incineration residues, such results will most likely be misunderstood. Revision of the standard method EN 13 137 is recommended to better suit incineration residues. The L/S ratio (the relationship between the mass of liquid and the mass of solid material), excessive carbonation (addition of CO2 until the pH in the solution was stable for 2.5 h) and extraction pH were the main factors controlling the mobility of DOC in incineration bottom ash. Up to ~60 weight-% of the TOC in the bottom ash could be mobilized by controlling these factors (i. e. by using them as parameters). Only a minor part of the TOC (~7 weight-%) in APC residues was extractable with water, indicating a high proportion of elemental carbon. Water-soluble organic compounds may affect the mobility of metals in several ways. The formation of DOC-metal complexes has a direct effect on the metal mobility. Biological degradation of organic material may also affect the metal mobility indirectly due to changes of pH and redox- potential. The complexation capacity of DOC can be used in the development of washing as a pre-treatment process of incineration residues. Excessive carbonation may be useful in a washing process to enhance the separation of metals. Further treatment-oriented investigations of bottom ashes and APC residues are recommended in the development of a washing process of the materials.Godkänd; 2006; 20070109 (haneit)
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Lagerkvist, Anders. "Om nedbrytnings- och transportprocesser i avfallsupplag." Licentiate thesis, Luleå tekniska universitet, Geovetenskap och miljöteknik, 1986. http://urn.kb.se/resolve?urn=urn:nbn:se:ltu:diva-17631.
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Herrmann, Inga. "Use of sedondary construction material in landfill cover liners." Licentiate thesis, Luleå : Luleå tekniska universitet/Samhällsbyggnad/Avfallsteknik, 2006. http://epubl.ltu.se/1402-1757/2006/65/LTU-LIC-0665-SE.pdf.
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Luthbom, Karin. "Uncertainty in environmental decision-making : effects of defined or undefined guidance in the decision process." Licentiate thesis, Luleå, 2004. http://epubl.luth.se/1402-1757/2004/64.
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Sandra, Gustafsson. "Key factors for introducing an improved climate adaptation for engineers and contractors working in multidisciplinary infrastructure projects." Thesis, KTH, Hållbar utveckling, miljövetenskap och teknik, 2018. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-233364.
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Climate change poses a critical threat to future development and is a reality that affects our society, our way of thinking and acting. The international body has taken common position against climate change in the expression of, inter alia, the Paris Agreement on climate change and the Sustainable Development Agenda. Likewise, the Swedish Government’s is aiming for climate neutrality by 2045. This in parallel to the fact that public awareness and knowledge of sustainability grow, the pressure to deliver environmentally friendly, ethical, and economically profitable products increases. The increased pressure on organizations within both public and private sectors leave no opportunity to escape as everyone is required to assist against the common goals. For organizational survival, it is thus important to find new ways of tying societal improvement with business, calling for new forms of knowledge and competence. Infrastructure investments play a fundamental function to achieve sustainable development and empower communities as they enhance economic growth, reduces inequality and improve the quality of life. Simultaneously, the climate impact from construction, operation, and maintenance of infrastructure is significant. Knowledge, practical advice and guidance to cope with increased requirements for reducing greenhouse gas emissions are available. In addition, awareness of the need for systematic climate work has increased in line with the introduction of new requirements and guidelines. Nevertheless, the climate perspective is still not a natural part of the mindset and process and the level of achievement of climate-related goals can be considered too low This study aims at investigating how climate mitigation practices can be updated to truly facilitate and enable integration of a climate perspective into the work of designers and contactors working in multidisciplinary infrastructure projects. The study was conducted in the context of a large infrastructure project concerning the construction and expansion of a significant railway segment in Sweden. Among other things, the project include construction of a tunnel in a highly demanding environment involving major climate challenges and a number of aggravating factors. By studying practices, collaborations, and use of external expertise in parallel with how projects proceed and actors operate the study contributes with deeper understanding of existing challenges and key factors for improved integration. The study's analyzed results indicate a number of contributing factors that complicate integration of a climate perspective, among others lack of ownership and risk-taking of the process, lack of knowledge, time and feedback, structural barriers, skepticism, inadequate communication, etc. The conclusion provides four recommendations for further addressing the matter: new contract and procurement models, development of educational packages, review and develop the toolbox of designers and engineers, and evaluate existing practices.Klimatförändringar utgör ett centralt hot mot vår framtida utveckling och är en realitet som påverkar vårt samhälle, sätt att tänka och agera. Världssamfundet har tagit gemensam ställning mot klimatförändringar i uttryck av bland annat Parisavtalet. Likaså har den svenska regeringen stiftat mål om klimatneutralitet år 2045. Detta parallellt med att allmänhetens ökade medvetenhet och kunskap om hållbarhet, ökar pressen att leverera miljövänliga, etiska och ekonomiskt lönsamma produkter. Den ökade pressen på organisationer inom både den offentliga och privata sektorn lämnar inget utrymme att ducka, eftersom alla är skyldiga att sträva mot de gemensamma målen. För organisatorisk överlevnad är det således viktigt att hitta nya sätt att kombinera samhällsnytta med företagsamhet vilket ökar efterfrågan av kompetens och kunskap inom området. Att investera i infrastruktur är en grundläggande funktion för att främja hållbar utveckling och stärka samhällen, eftersom det bidrar till ökat tillväxt, jämställdhet och förbättrad livskvalité. Samtidigt är klimatpåverkan från byggnation, drift och underhåll av infrastruktur betydande. Kunskap, praktiska råd och vägledning för hantering av ökade klimatkrav för minskade utsläpp av växthusgaser finns tillgängliga. Därtill har medvetenheten om behovet av systematiskt klimatarbete ökat i linje med att nya krav och riktlinjer introducerats. Trots detta, är klimatperspektivet fortsatt inte en naturlig del av tanke- och arbetsprocessen och nivån på uppnående av klimatrelaterade mål kan anses vara för låg. Denna studie syftar till att undersöka hur tillämpade arbetssätt kan uppdateras för att underlätta och möjliggöra integration av ett klimatperspektiv hos projektörer och entreprenörer som arbetar i multidisciplinära infrastrukturprojekt. Studien genomfördes i samband med ett stort infrastrukturprojekt som avser byggnation och utbyggnad av ett i Sverige betydande segment järnväg. Bland annat involverar projektet byggnation av en tunnel i en krävande miljö vilket medför stora klimatutmaningar och ett antal försvårande faktorer. Genom att studera tillämpade arbetssätt, samverkan och användning av extern expertis parallellt med hur projekt fortgår och aktörer arbetar bidrar studien med djupare förståelse av befintliga utmaningar och nyckelfaktorer för förbättrad integrering. Studien ger rekommendationer för vidare behandling av frågan. Studiens analyserade resultat indikerar ett antal bidragande faktorer som försvårar integreringen av klimatfrågan, bland annat bristande ägandeskap och riskupptagande i processen, bristande kunskap, tid och återkoppling, strukturella hinder, skepsis och bristfällig kommunikation. Studiens slutsats ger fyra rekommendationer för vidare arbete: nya kontrakts- och upphandlingsmodeller, utveckling av utbildningspaket, granskning och utveckling av verktygslådan till konstruktörer och ingenjörer samt utvärdering av befintliga arbetsmetoder.
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Murby, Fredrika. "Phosphorus reduction in wastewater using microalgae with different phosphorus starvation periods." Thesis, Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, 2021. http://urn.kb.se/resolve?urn=urn:nbn:se:ltu:diva-82778.
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Anthropogenic induced nutrients in the Baltic Sea have led to 97% of it being eutrophic. Phosphorus is regarded the main regulating nutrient, and nearly 25% of the nutrients coming to the Baltic Sea originate from wastewater treatment plants. To reduce the nutrient concentrations in the effluents from treatment plants, tertiary treatment methods based on chemical dosing have been the principal answer. The chemicals create a sludge in addition to remediating the water, which needs disposal. Methods for remediating secondary wastewater with microalgae exist but are not common in conventional wastewater treatment. However, using microalgae could be beneficial, since they use inorganic carbon (from the atmosphere and wastewater) and inorganic nutrients, while producing biomass and oxygen. The biomass in turn has a potential to be used in production of bioenergy, food, and fertilizers. This thesis investigated whether pre-phosphorus starvation of five different microalgae strains enhanced the removal rate of phosphorus from secondary wastewater. The aim was to determine the optimal starvation period of different algae strains and to achieve wastewater effluent concentrations below 0.1 mg/L at the shortest possible time. Algae were transferred to a phosphorus-free media for five, three, one and zero days before entering the wastewater in a batch reactor at a temperature of 27°C and a 16:8 hours light and dark regime. Phosphate and nitrate concentrations as well as biomass production were monitored during a period of ten days. The experiment was repeated three times using Chlorella Vulgaris and two times using Tetradesmus Obliquus, Ankistrodesmus Falcatus, Botryococcus Braunii and one time using Desmodesmus Communis. The secondary wastewater was obtained from a small wastewater treatment plant from the village Roja in Latvia. Prior to the experiments, it was filtered three times through filters with different pore sizes (the smallest pore size was 0.2 µm), and the average nitrate and phosphate concentrations were 21.3 ± 1.1 mg/L and 17.8 ± 0.56 mg/L, respectively. The nitrate to phosphate ratio was 1.8:1. It was possible to remove the inorganic phosphorus to concentrations below 0.1 mg/L within ten days, although it did not happen in all the reactors. It was found that in most cases pre-phosphorus-starvation increased the removal rate of phosphorus. For two of the strains, Chlorella Vulgaris and Ankistrodesmus Falcatus, the three-day of pre-starvation period was optimal, while two to three days was optimal for Tetradesmus Obliquus, compared to other pre-starvation periods. For Botryococcus Braunii the one-day and the zero-days starved batches removed the phosphorus most efficiently. For Chlorella Vulgaris and Ankistrodesmus falcatus nearly a 100% of the phosphorus was removed within seven days after three days of pre-starvation. Without pre-starvation, these strains achieved the same result after ten days. It was also found that the nitrogen was the limiting nutrient in the wastewater and that the different strains responded differently to the changes in environment brought on by the experiment. When using microalgae in wastewater treatment, the choice of strain greatly impacts the removal rate, as the likeliness for them to survive in a specific environment varies among strains. It was concluded that using microalgae as a wastewater treatment method could pose great benefits. However, more experiments with colder climate, non-pre-filtered wastewater, a less nutrient rich media, greater initial biomass concentrations and pilot tests are recommended. Another insight from this thesis was that the method for transferring algae between different media needs to be refined to reach the target concentration in a reactor (or other setup).
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Kylefors, Katarina. "Landfill leachate management : short and long term perspectives." Licentiate thesis, Luleå tekniska universitet, 1997. http://urn.kb.se/resolve?urn=urn:nbn:se:ltu:diva-18352.
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Eriksson, Solander Viktor. "Vattengeokemi och syre-väteisotoper som verktyg för spårning av vattenkällor vid vattentäkter : En fältstudie vid Gäddviksområdet i Luleå." Thesis, Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, 2020. http://urn.kb.se/resolve?urn=urn:nbn:se:ltu:diva-80464.
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Groundwater is an important source of drinking water where advanced knowledge in the area is of great importance in order to ensure the drinking water quality for future generations. Groundwater is chemically complex because it is formed from a large variety of water sources where the water comes from and passes through different geological and hydrological environments. Environmental forensics is an important area in environmental studies where a wide variety of analytical techniques are integrated to be able to trace and identify sources of pollution. In the Gäddvik project, environmental forensics is applied as a method for tracking pollution in naturally occurring waters. Concentrations of selected elements, oxygen- and hydrogenisotopes and cerium-anomalies have been used to show chemical differences between different water sources in groundwater reservoirs in the Gäddvik area. A sub-study at Kvarnträsket (a lake located in the Gäddvik area) has been carried out to track surface water intrusion in nearby groundwater used for drinking water. Different types of graphs and charts have been created from data on the area, where these have been used to give a simplified visualization of different geochemical trends for selected elements/isotopes. Quality differences between two nearby groundwater reservoirs have been studied and discovered, where one is Luleå’s main groundwater reservoir and the other is a backup groundwater reservoir. Surface water from the Luleå River has been detected in the main groundwater reservoir to a greater extent than in the backup groundwater reservoir. This may be since the main reservoir is under higher exposure and uses river water for artificial infiltration to the groundwater. Oxygen- and hydrogenisotopes have been shown to be useful for tracking and locating surface water infiltration in groundwater intended for drinking water.Grundvatten är en viktig källa för dricksvatten där en utvecklad kunskap inom området är av stor betydelse för att kunna säkerställa dricksvattenkvalitén för framtida generationer. Grundvatten är kemiskt komplext eftersom det bildas från en stor variation av vattenkällor där vattnet kommer från och passerar genom olika geologiska och hydrologiska miljöer. Environmental forensics är ett viktigt område inom miljöstudier där man integrerar en bred variation av analytiska tekniker för att kunna spåra och identifiera föroreningskällor. I Gäddviksprojektet tillämpas environmental forensics som metodik för spårning av föroreningar i naturligt förekommande vatten. Koncentrationer av valda element, syre- och väteisotoper samt cerium-anomalier har använts för att visa kemiska skillnader mellan olika vattenkällor vid vattentäkter i Gäddviksområdet. En delstudie vid Kvarnträsket (en sjö belägen i Gäddviksområdet) har genomförts för att spåra ytvattenintrång i närliggande grundvatten som används för dricksvatten. Olika typer av grafer och diagram har skapats från data över området, där dessa har använts för att förenklat visualisera olika geokemiska trender för valda element/isotoper. Kvalitetsskillnader mellan två närliggande vattentäkter har studerats och upptäckts där ena täkten är Luleås huvudvattentäkt och den andra är en reservvattentäkt. Ytvatten från Luleälven har upptäckts i huvudvattentäkten i större utsträckning än reservvattentäkten. En potentiell orsak till detta är att huvudvattentäkten är under högre belastning och använder älvvatten för konstgjord infiltration till grundvattnet. Syre- och väteisotoper har visats användbara för spårning och lokalisering av ytvattenintrång i grundvatten avsedda för dricksvatten.
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Belai, Merhawi. "Uttagsmöjligheter från en ytvattenkälla för konstgjord infiltration : Modellering av nettotillrinning in till sjön Återvallsträsket på Ingarö (Värmdö) i ett framtida klimatscenario." Thesis, KTH, Hållbar utveckling, miljövetenskap och teknik, 2020. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-281411.
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Sverige har god tillgång till vattenresurser tack vare det nordiska klimatet och den geologiska sammansättningen. Dock förväntas den pågående klimatförändring påverka Sveriges vattenresurser. Särskilt utsatta är kustnära områden som Värmdö vars geologi består till stor del av hårt kristallint berg och har begränsad tillgång till stora grundvattentäkter. Värmdö är dessutom ett av Sveriges snabbast växande kommuner och befolkningen förväntas öka med 58 procent fram till år 2050. Sammantaget kommer situationen kulminera till ett ökat tryck på kommunens vattenförsörjning, särskilt på sommaren när boende i kommunen nästan fördubblas. En vanlig metod för att stärka grundvattentillgången är konstgjord infiltration som innebär att vatten från en ytvattenkälla pumpas till en särskild infiltrationsbassäng och infiltreras ner till grundvattentäkten. Ingarö har en grundvattentäkt som Värmdö kommun avser förstärka med konstgjord infiltration med sjön Återvallsträsket som ytvattenkälla för att möta kommande utmaningar med vattenförsörjning till följd av klimatförändring och befolkningstillväxt. Denna uppsats syftar att uppskatta den framtida nettotillrinningen från avrinningsområdet för Återvallsträsket och bedöma huruvida det erforderliga uttaget från sjön är hållbart ur ett långsiktigt perspektiv med avseende på sjöns återhämtningsförmåga, befolkningstillväxt och ett tidigare domstolsbeslut som reglerar vattenståndet. Uppsatsens metodik utgörs av en litteraturstudie och tillämpad modellering. Återvallsträskets avrinningsområde har fastställts genom mjukvaruprogrammet ArcGIS med kartor och geo data från Lantmäteriet och SGU. Observerad meteorologiska data är hämtad från SMHI:s mätstationer på Värmdö och klimatscenariot har bearbetats av SMHI:s klimatforskningsenhet Rossby Centre. Tillrinningen har beräknats fram med hydrologiska beräkningsmetoder. En jämförelse sker genom tre ögonblicksbilder, en nutida med värden från år 2019 och två framtida prognostiserade modellberäkningar från år 2060 och 2099. Resultatet visar på en trend med ökad nederbörd under vår och sommar samt en nedgång under vinter och höst medan avdunstning ökar för samtliga årstider. Avrinningsområdet till Återvallsträsket har en area på 5,2 km2 och tillsammans med den månatliga nettotillrinningen antyds en god möjlighet till påfyllning från december till mars men under april till september finns en risk för otillräcklig återhämtning. Slutsatsen antyder att Återvallsträskets förmåga att användas som ytvattenkälla för konstgjord infiltration inte är entydig men med noggrann planering kan eventuella risker förebyggas och grundvattenmagasinet kan utökas.Ingarö has a groundwater resource that Värmdö Municipality intends to reinforce with artificial infiltration with the lake Återvallsträsket as a surface water source to meet future challenges with water supply as a result of climate change and population growth. This paper aims to investigate feasibility from a hydrological perspective in a future climate scenario. The thesis methodology consists of a literature study and applied modeling and the runoff has been calculated using hydrological calculation methods. A comparison is made of three snapshots, one for present times and two future forecast model calculations. The result shows a trend with increased precipitation during spring and summer and a decrease during winter and autumn while evaporation increases for all seasons. The catchment area to Återvallsträsket has an area of 5.2 km2 and, together with the monthly net inflow, suggests a good opportunity for replenishment December to March, but in April to September there is a risk of inadequate recovery. The conclusion suggests that the ability of Återvallsträsket to be used as a surface water source for artificial infiltration is not clear but with careful planning contingent risks can be prevented and the groundwater reservoir can be increased.
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Andersson, Julia, and Agnes Röllgårdh. "Sjörestaurering med hypolimnetisk tömning : Exemplet Hönsan, Hedemora." Thesis, KTH, Hållbar utveckling, miljövetenskap och teknik, 2020. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-281934.
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Restaurering av övergödda sjöar och hav är en betydande del av de miljöåtgärder som görs i Sverige och runt om i världen. Restaureringen är viktigt för att bibehålla en stor biologisk mångfald och en god vattenkvalitet i sjöar och hav. Ökade fosforhalter från gödsling bidrar till övergödning av sjöar och effektivare metoder för att reducera fosforhalter i vatten behöver utvecklas för att nå uppsatta nationella och internationella mål. Syftet med studien var att studera tidigare behandlingar av den eutrofa sjön Hönsan i Hedemora samt att göra ett experiment med ett filter, Polonite, för att undersöka om det är en effektiv metod för fosforreduktion. Hönsan har de senare åren lidit av dåligt siktdjup, fiskdöd samt algblomningar och tidigare behandlingsmetoder har haft positiva resultat i ytvattnet men bottenvattnet (hypolimnion) har fortfarande stora problem. Metoden bestod av ett kolonnförsök i laboratorium med avsikten att simulera hur fosfornivåerna i Hönsan skulle förändras med en sådan filtreringsprocess. Kolonnförsöket innebar att vatten och sediment, hämtat från hypolimnion i Hönsan, placerades i två akvarium. Akvarium 1, vars vatten pumpades genom Polonitefiltret och Akvarium 2, vars vatten pumpades genom kolonner med glaskulor i syfte att ge referensvärden. Resultatet visade att sjövattnet som passerat polonitefiltret reducerade fosforinnehållet med 95,1% medan referensvattnet endast hade en minskning med 7,1%. Utöver fosfornivåerna i akvariumen ändrades även pH i vattnet. Polonitefiltreringen medförde en höjning av, det initialt neutrala, pH-värdet till 12,03 när materialet var som mest reaktivt medan referensfiltreringen inte förändrade pH nämnvärt. Polonite visade sig vara ett effektivt sätt att rena fosfor i eutroft sjövatten men eftersom pH- nivån höjs så pass mycket efter filtrering bör det filtrerade vattnet inte återföras till hypolimnion utan till ytvattnet där det kan neutraliseras genom blandning med resterande vatten i sjön. En kombination av behandlingarna kornhalmskasetter, gröna öar samt polonitefiltrering kan därför anses vara en bra metod för restaurering av Hönsan. Förmågan hos Polonite att binda fosfor gör materialet även lämpligt som gödselmedel när dess bindningsförmåga har avstannat och filtret är mättat med fosfor.Restoration of lakes that suffer from eutrophication is a big part of the environmental work in Sweden and other countries around the world. Eutrophication in waters leads to decreasing biodiversity and bad water quality and the restoration work is important in order to reach global, national and regional environmental goals. Increasing levels of phosphorus is the main reason why the eutrophication process reaches a damaging level in lakes and finding a method for removal of phosphorus is key to be able to restore the lakes. The goal of this study was to analyze previous treatment methods that has been used in the lake Hönsan in Hedemora and to try a filter material for removal of phosphorus; Polonite. Hönsan has suffered from algae bloom and death of fish as a result of eutrophication. Treatments done on the surface of the lake has had positive results for the surface water, but the bottom layer of water is still damaged by high levels of phosphorus. To try the filter material, water and sediment was brought from Hönsan to KTH and used in an experiment in which Polonite’s phosphorus reduction capacity was tested. The results of the experiment showed that Polonite reduced 95,1% of the phosphorus in the water and that the filtration also resulted in a rise in pH-level. The conclusion of the experiment and this report is that Polonite is efficient as a material for phosphorus reduction through filtration. After filtration with Polonite the water should be returned to the surface water in the lake so as to be neutralized before reaching the bottom layer of water. A preferred treatment method for Hönsan is to combine filtration with Polonite with other treatments placed on the surface of the lake that has already been used in Hönsan.
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Dahlén, Lisa. "To evaluate source sorting programs in household waste collection systems." Licentiate thesis, Luleå tekniska universitet, Geovetenskap och miljöteknik, 2005. http://urn.kb.se/resolve?urn=urn:nbn:se:ltu:diva-17339.
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When evaluating and comparing household waste collection systems, various aspects are relevant to consider, e.g. environmental objectives, technical function, operating cost, types of recycling materials collected separately, property-close collection or drop-off system, economic incentives, information strategies, residential structure, social codes, etc. Data describing the actual waste flow is the basic input to evaluating the function of source-sorting programs. The questions raised are: How can household waste quantities and composition be measured? How can waste flow data from different collection systems be interpreted and compared? What factors influence the output of source-sorting programs? The usefulness and weaknesses of solid waste composition studies are discussed. Multivariate data analysis is applied in order to obtain an overview of collection and composition data, and identify influential variables, clusters and trends. In a case study, curbside collection of recyclables and weight-based billing respectively led to increased source-sorting activities. Other influential factors are listed and discussed. Eight indicators are proposed for facilitating comparisons of collection systems in an easily comprehensible way.Godkänd; 2005; 20061214 (haneit)
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Brännvall, Evelina. "Suitability of fly ash for construction and land applications." Doctoral thesis, Luleå tekniska universitet, Geovetenskap och miljöteknik, 2013. http://urn.kb.se/resolve?urn=urn:nbn:se:ltu:diva-17269.
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Municipal solid waste incineration fly ash is often landfilled or sent abroad for stabilization because it is considered a hazardous waste. These approaches to fly ash are both costly, and highlight the need for alternative and sustainable ash recycling. Both the needs of waste recycling and preservation of natural resources can be solved by using fly ashes as a secondary construction material and as soil fertilizer.Three types of fly ashes have been investigated in the laboratory experiments. Namely municipal solid waste incineration (MSWI), refuse-derived-fuel (RDF) and biofuel fly ashes. Factors influencing changes in chemical properties and mineralogical composition of RDF fly ash exposed to environmental conditions close to those that are found in a landfill top cover were evaluated in the accelerated ageing experiment. Element availability to leaching and plant uptake in soil amended with MSWI, biofuel fly ashes and biosolids was also evaluated.RDF fly ash exposed to the conditions found in a landfill top cover (20% CO2, 65% RH, 30°C T) lead to the chemical and mineralogical transformations that resulted in reduced leaching of most of the elements studied here. Only concentrations of Cl- in the leachates were an issue, because they still exceeded the leaching limit values; nevertheless the leaching of this element in aged ash decreased by 50% compared to fresh ash.Application of pelletized MSWI fly ash with biosolids on soil resulted in elevated total concentrations of As, Cd and Pb in soil (by 29%, 100% and 300%), but dissolved concentrations of these elements in soil pore water, except the As, were low as in the range of drinking water concentrations (98/83/EC). Furthermore, the concentrations of Cd and Pb in plant biomass were negligible regardless of the type of ash used.Based on the observations, RDF fly ash is considered as a suitable material to be used in a landfill liner. Whereas MSWI and biofuel fly ashes based on element availability for plants studies, could be considered suitable for land applications. But doses to be applied on soil should be adjusted to the type of ashes used to avoid accumulation of potentially toxic elements in soil over time.Godkänd; 2013; 20130827 (evebra); Tillkännagivande disputation 2013-10-04 Nedanstående person kommer att disputera för avläggande av teknologie doktorsexamen. Namn: Evelina Brännvall Ämne: Avfallsteknik/Waste Science and Technology Avhandling: Suitability of Fly Ash for Construction and Land Applications Opponent: Associate Professor Alessandra Polettini, University of Rome ”La Sapienza”, Rome, Italy Ordförande: Professor Anders Lagerkvist, Institutionen för samhällsbyggnad och naturresurser, Luleå tekniska universitet Tid: Fredag den 25 oktober 2013, kl 10.00 Plats: F1031, Luleå tekniska universitet
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Borg, Emelie, and de Moraes Felicia Pereira. "Varför sorterar inte Lidingöbor ut sitt matavfall? : Matavfallsinsamling för småhushåll på Lidingö." Thesis, KTH, Industriell ekologi, 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-210762.
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Lidingö har sedan 2010 erbjudit sina invånare att bli abonnenter av tjänsten för matavfallsinsamling. Trots årliga kampanjer har de dock inte samma anslutningsgrad som kommuner som har ett taxerings - och insamlingssystem som fungerar på liknande sätt. Syftet med detta arbete är därför att svara på; Varför sorterar inte småhus ut matavfall i Lidingö stad trots att det finns förutsättningar för det? Genom litteraturstudier och utskickad enkät till boende på Lidingö har anledningar till varför majoriteten av småhus-hushållen inte är abonnenter tagits fram samt vilka åtgärder som Lidingö stad kan bistå med för att få fler av dessa att bli abonnenter. Det som identifierades som anledningar till att Lidingöbor inte sorterar var främst att de var oroliga för lukt, de hade för lite matavfall och de saknade information. Kampanjer som ansågs fungera väl genom resultat från litteraturstudier i beteendeförändring och jämförelse med andra kommuner var att använda informatörer eller dörrknackare samt att involvera boende i funktionen och driften av systemet. De slutgiltiga åtgärdsförslagen till Lidingö var att synliggöra information bättre och på ett sätt som får de boende att känna sig personligt engagerade till att sortera samt att minska trösklarna i systemet.Lidingö has since 2010 offered residents to become subscribers of the food waste collection service. Despite annual campaigns they do not have the same connection rates as municipalities that have a taxation and collection system that works similarly. The purpose of this work is therefore to answer; Why does not single-family houses sort out food waste in Lidingö stad despite they have the conditions to do it? Through literature studies and a questionnaire sent to residents in Lidingö, reasons have been identified as for why the majority of small-family households are not subscribers, and what means Lidingö stad can use to get more subscribers. What was identified as a reason why citizens of Lidingö did not sort was primarily that they were worried about smell, they had too little food waste and they lacked information. Recommended campaigns that were identified through results from literature studies in behavioural change and comparison with other municipalities are; use informers or door-stepping and involve residents in the functioning and operation of the system. The final action proposals for Lidingö stad is to make information better visible and in a way that makes the residents feel personally involved in sorting and reducing the thresholds in the system.