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Quevedo-Martinez, Edgar Arturo. "A market assessment of greenhouse products and associated rural development in semi-arid regions of Mexico." Morgantown, W. Va. : [West Virginia University Libraries], 2009. http://hdl.handle.net/10450/10828.
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Thesis (M.S.)--West Virginia University, 2009.Title from document title page. Document formatted into pages; contains xi, 103 p. : ill. (some col.), col. map. Includes abstract. Includes bibliographical references (p. 68-69).
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Морозова, Ірина Анатоліївна, Ирина Анатольевна Морозова, Iryna Anatoliivna Morozova, and M. S. Naidenko. "Greenhouse Effect." Thesis, Видавництво СумДУ, 2008. http://essuir.sumdu.edu.ua/handle/123456789/16015.
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Joneus, Filip, and Andreas Ellingsen. "Smart Greenhouse." Thesis, Högskolan i Halmstad, Akademin för informationsteknologi, 2020. http://urn.kb.se/resolve?urn=urn:nbn:se:hh:diva-42371.
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Although automated greenhouse systems are widely used in industrial horticulture, the availability of similar, but simpler and affordable systems for residential greenhouses is low. The purpose of this project is, therefore, to design and develop a smart greenhouse system that supports standalone and remote monitoring and control of residential greenhouses. More specifically, this thesis focused on the design and implementation of the user interface and communication model of a smart greenhouse system. This project proposes a system architecture that can be used for converting a regular greenhouse into a smart greenhouse. The purpose of this is to enable users to monitor and control vital crop factors based on their needs. The resulting system is a userfriendly mobile application, a cloud-based storage service, and a responsive greenhouse system. Further development could focus on user experience and publish/subscribe distribution to achieve low power consumption.Automatiska växthussystem används i stor utsträckning inom industriell trädgårdsodling men tillgängligheten för liknande, enklare och prisvärda system för bostadshus är låg. Syftet med detta projekt är därför att designa och utveckla ett smart växthussystem som stödjer monitorering och kontroll av mindre privata växthus. Denna avhandling fokuserar specifikt på design och implementering av ett användargränssnitt och en kommunikationsmodell för ett smart växthussystem. Detta projekt föreslår en systemarkitektur som kan användas för att konvertera ett vanligt växthus till ett smart växthus. Syftet med detta är att göra det möjligt för användare att övervaka och kontrollera viktiga grödofaktorer baserat på deras behov. Det resulterande systemet är en användarvänlig mobilapplikation, en molnbaserad lagringstjänst och ett responsivt växthussystem. En vidareutveckling av systemet kan fokusera på användarvänlighet och publish/subscribe distribution för att uppnå låg energiförbrukning.
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Suta, Adin, and Karl-Filip Selander. "Automated Greenhouse." Thesis, KTH, Maskinkonstruktion (Inst.), 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-226686.
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In agriculture, growing plants is usually done with soil asthe growing medium. An alternative method for soil is usinga hydroponic system with plants submerged in water.In this thesis, a hydroponic system was built with the purposeof finding out suitable constants and loop-time of aPID controller to reach optimal pH value for plant growthof a nutrient solution, without intoxicating it. An Arduinouno micro controller was used to turn on and off a waterpump, oxygen pump and lights at certain intervals. ApH sensor was used to measure pH-levels in a tank, givingthe output from the pH-sensor as the input for thePID-controller. Depending on the output of the PID, twoservos opened valves to release either an alkaline or acidicsolution into the water reservoir. The results of the testsconducted show that it is possible to find working constantsand loop-time for the PID to successfully reach optimal pHof the water reservoir without intoxicating it.Att odla plantor görs i regel med jord som odlingsmedium,men som alternativ kan man använda ett hydroponiskt systemmed vatten som odlingsmedium istället för jord. I dennaavhandling, har ett hydroponiskt system byggts medsyfte att hitta lämpliga konstanter och looptid till en PIDkontroller för att neutralisera pH:t i en näringsvätska utanatt medföra en giftig miljö för växterna. En Arduino unomikrokontroller har använts för att sätta på och stänga aven vattenpump, syrepump och ljus i bestämda tidsintervall.En pH-sensor användes för att mäta pH-nivåerna i envattentank, utdatan från pH-sensorn blev indatan för PIDkontrollern.Beroende på utdatan från PID-kontrollern såöppnas två servo motorer ventiler för att antingen släppaut en basisk eller en sur lösning till vattentanken. Resultatenfrån testerna visar att det är möjligt att hitta fungerandekonstanter och looptid för en PID-kontroller för attframgångsrikt neutralisera pH:t i vattnet utan att förgiftadet.
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Lacroix, René. "A framework for the design of simulation-based greenhouse control." Thesis, McGill University, 1994. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=41652.
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The main objectives were: (1) to develop tools to aid in the design of enclosed agro-ecosystems, and (2) to use these tools to develop a prototype simulation-based control system. Three tools were developed: (1) a conceptual framework, (2) a (simulated) greenhouse system and (3) a simulation approach within OS/2.Part of the conceptual framework was dedicated to "conscious control", defined as a form of control practised by an entity that uses models of itself in its decision-making processes. The greenhouse system was composed of six modules (a simulation manager, a weather generator, a greenhouse model, a crop model, a Pavlovian controller and a cognitive controller), which were implemented under OS/2 as separate processes.
The greenhouse system was used to develop a prototype simulation-based controller. Primarily, the role of the controller was to determine temperature setpoints that would minimize the heating load. The simulation model used by the controller was an artificial neural network. The controller adapted temperature setpoints to anticipated meteorological conditions and reduced greenhouse energy consumption, in comparison with a more traditional controller.
Generally, the results showed the feasibility and illustrated some of the advantages of using simulation-based control. The research resulted in the definition of elements that will allow the creation of a methodological framework for the design of simulation-based control and, eventually, a theory of conscious control.
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Bjørnerem, Vegard Stølen. "Low Greenhouse GasEmission Ship." Thesis, Norges teknisk-naturvitenskapelige universitet, Institutt for marin teknikk, 2010. http://urn.kb.se/resolve?urn=urn:nbn:no:ntnu:diva-11441.
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The fleet consists of 6 LNG carriers where 3 have a loading capacity of 44 000 tons while the remaining 3 ships can lift 33 00 tons of LPG. Since the ships are set to operate at speeds between 14 and 20 knots it is necessary to upgrade the prime movers as the service speeds range from 14.5 to 16.7 knots. BW Clipper will prove to be far more effective in terms of fuel consumption compared to the other ships due to higher initial service speed and a relatively efficient engine. The fleet will operate within tramp shipping fulfilling 18 contracted orders and serving the spot market in between ordered shipments. The duration and the profitability of the orders influenced the net income. It is favorable to be committed to profitable contracted orders in recession while it is unfavorable to be bound to low rate contracted orders in prosperity. The ships were assigned to two to four contracted orders each. The fuel prices are changing rapidly and the magnitude of the variations can be vast. This impacts the shipping companies as the fuel costs are a large item of expenditure in the shipping industry. For the period between second half of 2006 and end 2007 I estimated the IFO 180 price to be 353 USD/ton, while it was 383 USD/ton in a defined prosperity level and 138 USD/ton in a defined recession level. The freight rates for the actual level, the prosperity level and the recession level were estimated to 36.5 USD/ton, 63 USD/ton and 25.7 USD respectively. The spot market potential was fully utilized at the prosperity level, 88% in the actual level while only 57.5% was utilized in the recession level.
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Li, Chi-cheong Markus, and 李志昌. "The trading of greenhouse gas." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2000. http://hub.hku.hk/bib/B42575485.
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McGinley, Susan. "Parasitic Wasps: Protecting Greenhouse Tomatoes." College of Agriculture and Life Sciences, University of Arizona (Tucson, AZ), 1998. http://hdl.handle.net/10150/622306.
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Kordesch, Wendy E. C. "Middle Eocene greenhouse climate instability." Thesis, University of Southampton, 2016. https://eprints.soton.ac.uk/402327/.
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Understanding warm climate states is increasingly important as projections of anthropogenic climate change indicate atmospheric carbon dioxide concentrations in the coming century not previously seen on Earth for tens of millions of years. The Eocene (~56-34 Ma) is a critical period in the long-term Cenozoic climate evolution, encompassing the transition from widespread greenhouse warmth and high atmospheric carbon dioxide levels pervasive during the early Eocene to an icehouse world with major Antarctic ice sheets and cooler temperatures. Increasingly, it has become apparent that global climate during this transition was not gradual; the middle Eocene is characterized by significant short-term climate variability with recent findings including both transient warming and cooling events. However, the timing, and nature of many of the climate fluctuations during this interval are poorly constrained. To this end, this thesis aims to better characterize the long-term background trends and investigate the nature of short-term transient perturbations during the greenhouse climate of the middle Eocene. In Chapter 2, new nine million year long benthic foraminiferal stable isotope records (~46 to 38 Ma) generated from recently drilled equatorial Pacific sediments with excellent age control are presented. These are the first records to document that the seven enigmatic equatorial Pacific Carbon Accumulation Events (CAEs) are not associated with transient global cooling and/or glaciation events, as previously hypothesized. Further, new carbonate accumulation records in Chapter 3 provide the first robust evidence for the presence of CAEs 3 and 4 in the Atlantic basin. Together, these findings constrain the feasibility of potential CAE forcing mechanisms and imply that there are only two viable mechanisms; (1) solute flux from continental weathering, and (2) increased organic carbon burial from marine assemblage changes. A new compilation (including new and published records) of carbonate accumulation records from a paleodepth transect (2-4 km) in the Atlantic and Pacific basins provides the first multi-basin look at deep-sea carbonate burial at high temporal resolution across the Middle Eocene Climatic Optimum global warming event (~40 Ma). New CCD and lysocline interpretations reveal for the first time that multiple rapid fluctuations (< 100 kyrs) and extreme lysocline shoaling (reaching > 2 km water depth) are superimposed on long-term trends. This finding implies multiple pulses of carbon input to the ocean–atmosphere system during the MECO and provides critical time constraints to potential forcing mechanisms, which have so far remained elusive. In the final Chapter 4, new lithological and geochemical data from the Atlantic and Pacific Basins are presented which reveal the global nature of the transient ‘C19r event’ (~41.5 Ma) and confirm that the event meets the criteria to be defined as a ‘hyperthermal’. Further, analyses of the stable isotope datasets suggests that the C19r event was not exceptional and is one (albeit the most extreme) of a large number of transient ‘warming’ events throughout the middle Eocene, adding to the growing body of data implying that hyperthermal occurrence is pervasive outside of the very warm late Paleocene and early Eocene.
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Li, Chi-cheong Markus. "The trading of greenhouse gas." Click to view the E-thesis via HKUTO, 2000. http://sunzi.lib.hku.hk/hkuto/record/B42575485.
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Bernier, Hervé 1952. "Energy conservation using a soil heat exchanger-storage system in a commercial type greenhouse." Thesis, McGill University, 1987. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=64033.
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Olesniewicz, Timothy J. "Unanticipated Consequences of Regional Greenhouse Gas Policies: Criteria Emissions and the Regional Greenhouse Gas Initiave." Fogler Library, University of Maine, 2008. http://www.library.umaine.edu/theses/pdf/OlesniewiczTJ2008.pdf.
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He, Lan. "Characteristics of solar radiation transmission into a double-walled acrylic pellet-insulated greenhouse." Connect to resource, 1987. http://rave.ohiolink.edu/etdc/view?acc%5Fnum=osu1145366507.
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Behzadi, M. A. "True digital control of greenhouse systems." Thesis, Lancaster University, 1989. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.236319.
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Kuvare, Uparura S. K. (Uparuru Silvanus Karl). "Greenhouse production of watermelon (Citrullus lanatus)." Thesis, Stellenbosch : Stellenbosch University, 2005. http://hdl.handle.net/10019.1/50361.
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Thesis (MSc)--Stellenbosch University, 2005.ENGLISH ABSTRACT: Various researchers have determined that salinity causes several kinds of damage to plants such as germination inhibition, metabolic disturbances, yield reduction and quality losses. However, the severity of salt damage has been found to be dependent on the cultivar, level of salinity, period of exposure to salinity, and the growth stage of the plant. An understanding of the severity of salinity and its potential negative impacts on crops is essential to optimise production. Knowledge of seed vigour, expressed as germination percentage and germination rate at the optimum temperature for germination, would provide growers with valuable information to measure and compare the viability of seed lots. A study was done where fresh and aged seeds of two watermelon cultivars were investigated in germination tests under laboratory conditions at four salinity levels and five temperature regimes. The best germination was achieved at 4 mS cm-1 for both cultivars, Odem and Paladin. At 8 mS cm-I, the germination percentage for Paladin was 31% better than for Odem. The germination time for aged Odem seeds was significantly delayed at this EC 8 level but ageing of Paladin seeds had no detrimental effect at this EC level. Paladin germinated significantly better than Odem at the relatively low temperature range of I5-20°C, indicating that it is well-adapted for early planting. A new plant growing system, using vertical training of two shoots was tested in a greenhouse, aiming to optimise the growth regulating capabilities of this crop environment. Traditional watermelons are open-field planted in rows at low densities. Even with this plant spacing, by harvesting time the vines are spread in such a way that the foliage laterally covers the inter-row spacing, making cultivation practices such as spraying, weeding and harvesting difficult and almost impossible. The production of greenhouse crops is advantageous, but involves a number of cultural inputs and techniques for optimum yields. The effects of plant pruning systems and salinity levels on watermelon cultivars (Odem and Paladin) in a low-cost greenhouse were studied using a drain-to-waste fertigation system. Changing the nutrient solution from a low salinity level (EC 4 mS cm1) during vegetative growth to EC 4 mS cm-I after pollination, did not reduce fruit mass, but significantly increased the sugar yield of Odem, the icebox-type cultivar. Excessive pruning (less leaves per shoot) was more efficient with low salinity levels than at a high salinity level. Moderate pruning (more leaves per shoot) represented a good system, producing fruits of lesser weight and acceptable quality.
AFRIKAANSE OPSOMMING: Verskeie navorsers het reeds die skadelike gevolge van brak toestande op ontkieming, plant metabolisme, opbrengs en kwaliteit van gewas plante ondersoek. Die omvang van die skade kan deur kultivars, die konsentrasie soute, die periode van blootstelling asook plante se groeistadium bepaal word. 'n Goeie begrip van die potensiële skadelikheid van hoë sout konsentrasies op gewasse is nodig om produksie te optimaliseer. Inligting oor die kiemkragtigheid van saad, uitgedruk as die persentasie ontkieming asook die ontkiemingstempo, is vir kwekers nodig ten einde te verseker dat goeie saad gebruik kan word. 'n Ondersoek is gedoen waar vars asook verouderde saad van twee waatlemoen kultivars onder laboratorium toestande by vier sout peile en vyf temperature ontkiem is. Die beste ontkieming vir beide kultivars, Odem en Paladin, is gevind waar die elektriese geleiding (Eï,') 4 mS cm-1 was. Teen 8 mS cm-1 was die persentasie ontkieming vir Paladin 31% beter as vir Odem. Veroudering van Odem saad het 'n betekenisvol swakker ontkiemingstempo met'n Ee van 8 mS cm-1 getoon terwyl verouderde Paladin saad nie by hierdie Ee swakker vertoon het nie. Paladin het by die relatief lae temperatuur sone van 15-20oe betekenisvol beter as Odem saad ontkiem wat daarop dui dat dit vir vroeë aanplantings geskik is. 'n Nuwe produksiestelsel, waar twee lote per plant vertikaal in 'n V-vorm opgelei is, is in 'n kweekhuis getoets in 'n poging om die groeiregulerende potensiaal van so 'n omgewing te optimaliseer. Waatlemoene word tradisioneel in rye teen 'n lae plantdigtheid in veldaanplantings verbou. Met so 'n praktyk ontwikkel daar soveel ranke tussen die rye dat praktyke soos onkruid beheer, plaagbeheer en oes bemoeilik word. Die produksie van gewasse in kweekhuise hou voordele in maar 'n aantal insette en spesiale tegnieke is nodig vir optimum opbrengs. Die invloed van snoeipraktyke en soutpeile is met twee waatlemoen kultivars (Odem en Paladin) in 'n lae-koste kweekhuis ondersoek deur 'n sisteem te gebruik waar voedingsoplossings in vry dreinerende sakke met saagsels gedrup is. Waar die Ee van die voedingsoplossing voor vrugset 2 mS cm-1 was en toe vir die periode van vrugontwikkeling tot 4 mS cm-1 verhoog is, het geen vrugverkleining by Odem gevolg nie terwyl die suikeropbrengs wel verhoog het. Oormatige verwydering van blare was minder skadelik met 'n lae EC as waar die EC hoog was. 'n Matige snoeiproses met meer blare per loot, het 'n goeie produksie van aanvaarbare vruggrootte en 'n goeie kwaliteit verseker.
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Смоленніков, Денис Олегович, Денис Олегович Смоленников, Denys Olehovych Smolennikov, and Victoria Kubatko. "The greenhouse effect and global warming." Thesis, Видавництво СумДУ, 2007. http://essuir.sumdu.edu.ua/handle/123456789/7989.
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Tran, Stephan, and Robert Alexandersson. "Small-scale biogas and greenhouse system." Thesis, KTH, Industriell ekologi, 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-210631.
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Greenhouse cultivation is a growing industry, especially in mild climates, much due to the ability toadjust the growing conditions and increased water utilization efficiency. The most important aspect onthe cultivation is the indoor temperature. The variation in temperature is due to the Swedish climatewhere the highest and lowest outdoor temperature respectively varies greatly during the year. To enableoptimal indoor climate additional heating is required during colder periods. Presently, most of theexisting greenhouses utilizes combustion of fossil fuels for heating, which contributes to the climatechange through the emissions of greenhouse gases. One way to circumvent this impact is to exchangethe fossil fuels with biogas. Combining biogas production and greenhouse cultivation enables synergiesand a more closed cycle of material flow can be achieved. However, this combination is rather immaturedue to lacking previous research, giving this report its main purpose, to examine the synergies andsustainability of combining a greenhouse with small-scale biogas production. Initially, an extensive literature study was carried out followed by a simulation based on the obtainedknowledge. The simulation was comprised of two greenhouses with different geometries, one with theshape of an arch with polyethylene-film cladding and the other with a sawtooth roof with glass cladding,both with two layers. The other properties such as internal area and volume are more or less the samefor the simulated greenhouses. Useful data such as outdoor temperature, rainfall and solar irradiationetc. was obtained for the city of Enköping, Sweden. The calculations for the models were carried out inthe program Microsoft Excel. In order to evaluate the feasibility of these models a reference greenhousewas studied, which had similar properties and conditions. The optimal temperature for tomato cultivation is 20° C, and to maintain this level over the entire yearit was found that the heat requirements were 89 500 kWh for the arched greenhouse and 94 400 kWhfor the sawtooth greenhouse. In comparison with the reference greenhouse, the heat requirement wasaround 200 kWh per m2 and year less in the simulated greenhouses. Furthermore, it was found thataround 31 800 kWh of cooling is required over the year (249 kWh per m2 and year) for the archedgreenhouse and 30 900 kWh per year (241 kWh per m2 and year) for the sawtooth greenhouse, to keepthe indoor temperature at 20 °C. Moreover, two to three possible harvests annually gives the yield of 3456-5184 kg tomatoes per year. Both the simulated greenhouses are feasible concepts, however thesawtooth greenhouse is a better option due to its increased longevity and lower contribution ofgreenhouse gas emissions over time. Furthermore, more research needs to obtain a fully closed cycle.
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Singh, Satnam. "Autonomous robotic vehicle for greenhouse spraying." [Gainesville, Fla.] : University of Florida, 2004. http://purl.fcla.edu/fcla/etd/UFE0002309.
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Miranda, Trujillo Luis Carlos. "Artificial Neural Networks in Greenhouse Modelling." Doctoral thesis, Humboldt-Universität zu Berlin, 2018. http://dx.doi.org/10.18452/19354.
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Moderne Präzisionsgartenbaulicheproduktion schließt hoch technifizierte Gewächshäuser, deren Einsatz in großem Maße von der Qualität der Sensorik- und Regelungstechnik abhängt, mit ein. Zu den Regelungsstrategien gehören unter anderem Methoden der Künstlichen Intelligenz, wie z.B. Künstliche Neuronale Netze (KNN, aus dem Englischen).
Die vorliegende Arbeit befasst sich mit der Eignung KNN-basierter Modelle als Bauelemente von Klimaregelungstrategien in Gewächshäusern. Es werden zwei Modelle vorgestellt: Ein Modell zur kurzzeitigen Voraussage des Gewächshausklimas (Lufttemperatur und relative Feuchtigkeit, in Minuten-Zeiträumen), und Modell zur Einschätzung von phytometrischen Signalen (Blatttemperatur, Transpirationsrate und Photosyntheserate). Eine Datenbank, die drei Kulturjahre umfasste (Kultur: Tomato), wurde zur Modellbildung bzw. -test benutzt.
Es wurde festgestellt, dass die ANN-basierte Modelle sehr stark auf die Auswahl der Metaparameter und Netzarchitektur reagieren, und dass sie auch mit derselben Architektur verschiedene Kalkulationsergebnisse liefern können. Nichtsdestotrotz, hat sich diese Art von Modellen als geeignet zur Einschätzung komplexer Pflanzensignalen sowie zur Mikroklimavoraussage erwiesen. Zwei zusätzliche Möglichkeiten zur Erstellung von komplexen Simulationen sind in der Arbeit enthalten, und zwar zur Klimavoraussage in längerer Perioden und zur Voraussage der Photosyntheserate. Die Arbeit kommt zum Ergebnis, dass die Verwendung von KNN-Modellen für neue Gewächshaussteuerungstrategien geeignet ist, da sie robust sind und mit der Systemskomplexität gut zurechtkommen. Allerdings muss beachtet werden, dass Probleme und Schwierigkeiten auftreten können. Diese Arbeit weist auf die Relevanz der Netzarchitektur, die erforderlichen großen Datenmengen zur Modellbildung und Probleme mit verschiedenen Zeitkonstanten im Gewächshaus hin.One facet of the current developments in precision horticulture is the highly technified production under cover. The intensive production in modern greenhouses heavily relies on instrumentation and control techniques to automate many tasks. Among these techniques are control strategies, which can also include some methods developed within the field of Artificial Intelligence. This document presents research on Artificial Neural Networks (ANN), a technique derived from Artificial Intelligence, and aims to shed light on their applicability in greenhouse vegetable production. In particular, this work focuses on the suitability of ANN-based models for greenhouse environmental control. To this end, two models were built: A short-term climate prediction model (air temperature and relative humidity in time scale of minutes), and a model of the plant response to the climate, the latter regarding phytometric measurements of leaf temperature, transpiration rate and photosynthesis rate. A dataset comprising three years of tomato cultivation was used to build and test the models. It was found that this kind of models is very sensitive to the fine-tuning of the metaparameters and that they can produce different results even with the same architecture. Nevertheless, it was shown that ANN are useful to simulate complex biological signals and to estimate future microclimate trends. Furthermore, two connection schemes are proposed to assemble several models in order to generate more complex simulations, like long-term prediction chains and photosynthesis forecasts. It was concluded that ANN could be used in greenhouse automation systems as part of the control strategy, as they are robust and can cope with the complexity of the system. However, a number of problems and difficulties are pointed out, including the importance of the architecture, the need for large datasets to build the models and problems arising from different time constants in the whole greenhouse system.
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Hill, Heather. "Local government and greenhouse action in South Australia /." Title page, table of contents and abstract only, 1998. http://web4.library.adelaide.edu.au/theses/09ENV/09envh646.pdf.
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Wilkerson, Erin Georgette. "Plant evapotranspiration in a greenhouse on Mars." [Gainesville, Fla.] : University of Florida, 2005. http://purl.fcla.edu/fcla/etd/UFE0012400.
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van, Mourik Caroline A. "The Greenhouse - Icehouse Transition : a dinoflagellate perspective." Doctoral thesis, Stockholm University, Department of Geology and Geochemistry, 2006. http://urn.kb.se/resolve?urn=urn:nbn:se:su:diva-1073.
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Through the analysis of the stratigraphic and spatial distribution of organic walled dinoflagellate cysts (dinocysts) from climatologically and oceanographically key sites, this project aims to contribute to a better understanding of the Eocene-Oligocene (E/O) environmental changes and their timing. A central issue is to identify the global environmental changes which are responsible for the Eocene cooling and its underlying mechanisms with the focus on the Oligocene isotope-1 (Oi-1) event, thought to mark the onset of major Antarctic glaciation.
Two low-latitude sites were selected, Blake Nose (western North Atlantic) and Massignano (central Italy). For the first time a coherent taxonomy and biostratigraphy of dinocysts was established for the late Eocene at these latitudes. A high resolution correlation was established between the Massignano E/O Stratotype Section and the stratigraphically more extended ‘Massicore’. The composite section was used to analyse sea surface temperature (SST) change across the greenhouse-icehouse transition by means of dinocyst distribution.
At Massignano, the Oi-1 event was recognised both qualitatively and quantitatively. In the power spectrum of the SSTdino the ~100 and ~400 kyr eccentricity cycles may be distinguished and correlated with La04. When orbitally tuned, the E/O GSSP dates ~100 kyr older than the Oi-1 event. The boundary’s age could either be ~33.75 or ~34.1 Ma, both differ significantly from the ~33.9 Ma age in the GTS 2004.
Furthermore, when the data from the low-latitude sites were combined with extensive datasets from the Proto North Atlantic and adjacent regions, a suite of species sensitive to changes in SST was recognised. Their first and last occurrences reflect seven distinct phases of decreasing SSTs during the Middle Eocene to earliest Oligocene.
These results clearly indicate that atmospheric cooling together with higher frequency orbital forcing played a key role in the transition from the Greenhouse to the Icehouse world.
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Van, Mourik Caroline A. "The greenhouse - icehouse transition : a dinoflagellate perspective /." Stockholm : Department of Geology and Geochemistry, Stockholm University, 2006. http://urn.kb.se/resolve?urn=urn:nbn:se:su:diva-1073.
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Frost, Robin. "Quantifying greenhouse gases in business supply chains." Thesis, Lancaster University, 2017. http://eprints.lancs.ac.uk/87614/.
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This thesis is written in the context of a world that is on the brink of experiencing severe climate change, and as a result must explore a variety of methods for reducing greenhouse gas (GHG) emissions. Whilst national governments and international organisations enact treaties and frameworks, the role of business as a driver of increasing GHG emissions is also being examined. In these circumstances the measurement of organisational footprints is of considerable interest. (Berners-Lee, et al., 2011) showed how the supply chain footprint of a small leisure business could be estimated using Environmentally Extended Input-Output (EEIO) modelling. The research presented in this thesis describes the updating of this model to use the most up to date ONS data. This model was used over several years with a UK based international telecommunications company. The implementation of the model, and several extensions to the methodology are presented along with summary results of the analysis. The case study demonstrates the suitability and flexibility of EEIO models for reporting supply chain footprints in organisations. A critique of the technique and further developments of the model are described.
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Welch, Bertie. "Trace greenhouse gas fluxes in upland forests." Thesis, Open University, 2018. http://oro.open.ac.uk/55812/.
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Tree stems can act as a conduit for trace greenhouse gases (GHG) produced in the soil. However, the majority of studies describing tree stem fluxes of methane (CH₄) and nitrous oxide (N₂O) have focused on wetland ecosystems. Tree stem fluxes of GHGs on free-draining soils are understudied, but they are assumed to be a source of CH₄ and a weak source of N₂O. The work presented in this thesis aimed to determine how climatic variables, soil abiotic conditions, and tree species influence CH₄ and N₂O fluxes in forests on free-draining soil. Soil and stem CH₄ and N₂O fluxes were measured in lowland tropical rainforest in Panama, Central America and temperate woodland in the UK, using chambers installed on the forest floor or strapped to individual stems of two common tree species. Air samples were collected every two to four weeks during 5 months in 2014 and during November 2015 at the tropical site, and between February 2015 and January 2016 at the temperate site. Tree stem CH₄ fluxes differed significantly between species at both sites and stem N₂O fluxes also differed between species at the tropical site. However, there was little variation in soil CH₄ or N₂O fluxes. At both sites, tree-mediated CH₄ fluxes declined from positive values (emission) at the stem base to negative values (uptake) higher up. Stem CH₄ fluxes generally increased significantly with solar radiation, suggesting a link to photosynthetic activity mediated by tree water transport. Collectively, these results show that trees on free-draining soils could act as net sinks for CH₄ and N₂O. These findings will improve GHG budgets because tree stem uptake is currently unaccounted for. In particular, if uptake of CH₄ by tree stems on free-draining soils is widespread, the global terrestrial CH₄ sink could be much larger than currently estimated.
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Branfield, G. R. "Thermal charcteristics of a greenhouse for aquaculture." Thesis, Stellenbosch : University of Stellenbosch, 2006. http://hdl.handle.net/10019.1/1794.
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Thesis (MScEng (Mechanical and Mechatronic Engineering))--University of Stellenbosch, 2006.Successful housing and breeding of exotic animals or plants often requires an environment that is quite different to the ambient conditions present. The current study approached the problem of sub-optimal water temperatures experienced by Central African Bream (Tilapia) housed within a South African greenhouse during winter months. A theoretical and experimental study of fundamental heat and mass transfer processes relevant to an aquacultural greenhouse was conducted. Experimental results were generally in agreement with those of previous researchers; while evaporation tests were found to concur particularly well with an analytical equation developed. The experimental results were used to develop a simple glass greenhouse model to evaluate the expected thermal behaviour during the coldest time of the year. Manipulation of the model revealed that water has the ability to absorb large quantities of solar radiation and regulate temperature fluctuations within such a system, and that the appropriate use of thermal insulation during both the night and day can maintain acceptable water temperatures for extended periods of time. With the conclusions drawn from the experimentation and modelling done, an optimised conceptual greenhouse design was presented, along with associated guidelines and principles for attaining the required water temperatures, and consequently providing the exotic fish specie with a healthy environment.
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Attalla, Daniela, and Wu Jennifer Tannfelt. "Automated Greenhouse : Temperature and soil moisture control." Thesis, KTH, Maskinkonstruktion (Inst.), 2015. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-184599.
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In this thesis an automated greenhouse was built with the purpose of investigating the watering system’s reliability and if a desired range of temperatures can be maintained. The microcontroller used to create the automated greenhouse was an Arduino UNO. This project utilizes two different sensors, a soil moisture sensor and a temperature sensor. The sensors are controlling the two actuators which are a heating fan and a pump. The heating fan is used to change the temperature and the pump is used to water the plant. The watering system and the temperature control system was tested both separately and together. The result showed that the temperature could be maintained in the desired range. Results from the soil moisture sensor were uneven and therefore interpret as unreliable.I denna tes byggdes ett automatiserat växthus med syftet att undersöka dess bevattningssystems pålitlighet samt om ett önskat temperaturspann kan bibehållas. Microkontrollern för att bygga detta automatiserade växthus var en Arduino UNO. Detta projekt använder sig av två olika sensorer, en jordfuktsensor och en temperatursensor. Sensorerna kontrollerar en värmefläkt och en pump. Värmefläkten används för att ändra temperaturen och pumpen för att vattna plantan. Bevattningssystemet och temperaturstyrningen har testats både separat och tillsammans. Resultatet visar att temperaturen kan bibehållas inom det önskade spannet. Resultaten från jordfuktsensorn var ojämna och därför tolkats som opålitliga.
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Angeja, Joey M. "Automated Pruning of Greenhouse Indeterminate Tomato Plants." DigitalCommons@CalPoly, 2018. https://digitalcommons.calpoly.edu/theses/1839.
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Pruning of indeterminate tomato plants is vital for a profitable yield and it still remains a manual process. There has been research in automated pruning of grapevines, trees, and other plants, but tomato plants have yet to be explored. Wage increases are contributing to the depleting profits of greenhouse tomato farmers. Rises in population are the driving force behind the need for efficient growing techniques. The major contribution of this thesis is a computer vision algorithm for detecting greenhouse tomato pruning points without the use of depth sensors. Given an up-close 2-D image of a tomato stem with the background excluded, the algorithm proposed in this work can detect and mark the tomato suckers.
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Jachym, Anne-Laure. "Economic Growth, Greenhouse Gases and Environmental Regulation." Master's thesis, Université Laval, 2020. http://hdl.handle.net/20.500.11794/38154.
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Dans cette étude, nous cherchons à mesurer l’impact des émissions anthropogéniques de gaz à effet de serre sur la croissance économique dans un modèle de convergence conditionnelle. Nous nous intéressons au dioxyde de carbone, au méthane, au protoxyde d’azote et au groupe des "gaz F", ainsi qu’à l’effet de la somme de ces polluants, c’est-à-dire la quasi totalité des gaz à effet de serre. Notre échantillon est composé de 81 pays, avec une variété de niveaux de revenu par habitant, entre 1993 et 2012. Nous définissons deux sous-périodes de 10 ans et nous régressons la croissance économique sur la croissance des émissions de chaque polluant séparément, sur le PIB de la première année de la période et sur plusieurs variables de contrôle. Face au risque de biais de causalité inversée entre les émissions de pollution et la croissance économique, et entre l’investissement et la croissance économique, nous décidons d’utiliser les données passées comme variables instrumentales. Plus précisément, les données de la première année de la période sont utilisées comme instruments pour la pollution et l’investissement. Mis à part le CO2, nous trouvons qu’aucun des gaz à effet de serre n’a d’impact significatif sur la croissance économique. La croissance des émissions de CO2 semble avoir un impact positif sur la croissance économique. Cet impact apparaît moins fort sur la seconde période (2003-2012) que sur la première (1993-2002). De plus, il semble plus fort pour la moitié la plus riche des pays de notre échantillon.In this study, we investigate the effect of anthropogenic greenhouse gas emissions on economic growth in a conditional convergence framework. We look at carbon dioxide, methane, nitrous oxide and the group of "F gases", as well as the effect of the sum of these pollutants, i.e. almost all greenhouse gases. Our sample is composed of 81 countries with a variety of per capita income levels and covers the period between 1993 and 2012. We define two ten-year periods and regress economic growth on emissions growth of each pollutant separately, on the first-year GDP of the period and on several control variables. To address the issue of inverse causality bias between pollution emissions and economic growth, as between investment and economic growth, we use an instrumental variable methodology. We use past data to instrument pollution and investment. More precisely, the data of the first year of the period are used as instruments. We find that, except for CO2, greenhouse gas emissions growth does not generate economic growth. CO2 emissions growth has a positive impact on economic growth. Interestingly, this impact is less pronounced between 2003 and 2012, as compared to the 1993-2002 period. In addition, the impact of CO2 emissions growth is stronger in the richer half of countries in our sample.
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Guess, Michael James. "Heating of greenhouse crops with microwave energy." Thesis, University of Leeds, 2011. http://etheses.whiterose.ac.uk/6763/.
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The greenhouse vegetable industry in Northern Europe is an extensive, high value and energy-intensive horticultural sector that is vital for food supply and security in Europe. Despite technical and legislative innovation over a period of thirty years, little improvement has been made in the reduction of absolute energy consumption for heating greenhouse growing space. A novel free-space microwave system for heating greenhouse crops volumetrically is proposed. and demonstrated. It is estimated that such a system can use one-third of the energy of a conventional heating system. This would allow for significant reductions in energy consumption, reduce environmental damage and provide financial savings of several billion Euros. Experiments on real plants demonstrate microwave heating utilising ISM band frequencies as a viable method for heating growing plants from seedling to fruition and reveal plant and fruit quality that is comparable to that attained by conventional heating. Non-uniformity of electric-field distribution within the plants, both between and within plant components, is identified as the main limiting factor during microwave heating and can result in localised burning. This can cause catastrophic failure when occurring on stems. The necessary reduction in power and the resultant decrease in average plant temperature delays development relative to conventionally-heated plants. Poor leaf heating and development is the main source of delay in fruit formation. A novel practical technique for improving inter- and intra-object heating uniformity is thus also presented and demonstrated. This method utilises circularly polarised incident waves to allow more regular heating of plant components and greater consistency of heating between different plant components. Furthermore, this technique can be applied generally to other dielectric heating scenarios where heating non-uniformity is a problem, specifically in industrial processes. The concept of plant sectors and sections is also defined to allow for valid comparison of the energy consumption of conventional and microwave heating systems, 1Il a commercial setting.
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Fitz-Rodriguez, Efren. "Decision Support Systems for Greenhouse Tomato Production." Diss., The University of Arizona, 2008. http://hdl.handle.net/10150/195798.
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The purpose of greenhouse crop systems is to generate a high quality product at high production rates, consistently, economically, efficiently and in a sustainable way. To achieve this level of productivity, accurate monitoring and control of some processes of the entire biophysical system must be implemented. In addition, the proper selection of actions at the strategic, tactical and operational management levels must be implemented.Greenhouse management relies largely on human expertise to adjust the appropriate optimum values for each of the production and environmental parameters, and most importantly, to verify by observation the desired crop responses. The subjective nature of observing the plant responses, directly affects the decision-making process (DMP) for selecting these `optimums'. Therefore, in this study several decision support systems (DSS) were developed to enhance the DMP at each of the greenhouse managerial levels.A dynamic greenhouse environment model was implemented in a Web-based interactive application which allowed for the selection of the greenhouse design, weather conditions, and operational strategies. The model produced realistic approximations of the dynamic behavior of greenhouse environments for 28-hour simulation periods and proved to be a valuable tool at the strategic and operational level by evaluating different design configurations and control strategies.A Web-based crop monitoring system was developed for enhancing remote diagnosis. This DSS automatically gathered and presented graphically environmental data and crop-oriented parameters from several research greenhouses. Furthermore, it allowed for real-time visual inspection of the crop.An intelligent DSS (i-DSS) based on crop records and greenhouse environment data from experimental trials and from commercial operations was developed to characterize the growth-mode of tomato plants with fuzzy modeling. This i-DSS allowed the discrimination of "reproductive", "vegetative" and "balanced" growth-modes in the experimental systems, and the seasonal growth-mode variation on the commercial application.An i-DSS based on commercial operation data was developed to predict the weekly fluctuations of harvest rates, fruit size and fruit developing time with dynamic neural networks (NN). The NN models accurately predicted weekly and seasonal fluctuations of each variable, having correlation coefficients (R) of 0.96, 0.87 and 0.94 respectively, when compared with a dataset used for independent validation.
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Sinisalo, Jukka. "Estimation of greenhouse impacts of continuous regional emissions /." Espoo : Technical Research Centre of Finland, 1998. http://www.vtt.fi/inf/pdf/publications/1998/P338.pdf.
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Gibson, Amber I. "Mitigation options for greenhouse gas emissions from agriculture." Thesis, Imperial College London, 2002. http://hdl.handle.net/10044/1/8592.
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Boereboom, Thierry. "Greenhouse gases investigations in ice from periglacial environments." Doctoral thesis, Universite Libre de Bruxelles, 2012. http://hdl.handle.net/2013/ULB-DIPOT:oai:dipot.ulb.ac.be:2013/209673.
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L’environnement périglaciaire en général et les régions de permafrost en particulier, connus pour être très sensibles au changement climatique actuel, sont le sujet de beaucoup d’études sur les émissions de gaz à effet de serre. En effet, le dégel de ces milieux engendre la mobilisation d’une quantité importante de matière organique, précédemment piégée par le froid, favorisant les émissions de dioxyde de carbone et/ou de méthane. L’objectif premier, du présent travail, est de contribuer à l’étude des gaz enfermés dans certains types de glace de ces régions afin de mieux quantifier leur impact potentiel sur le climat.Dans un premier temps, une analyse multiparamétrique a été menée sur deux coins de glace du nord de la Sibérie dans la cadre d’une collaboration avec l’Alfred Wegener Institut (Allemagne). Cette première approche a révélé que l’analyse conjointe de la cristallographie, de l’orientation des axes optiques, du contenu en gaz total et de la composition en gaz des coins de glace est un outil puissant, complémentaire aux analyses des isotopes stables, pour comprendre les conditions paléo-climatiques qui ont régi la construction des coins de glace. Cette étude soutient également l’hypothèse de variations spatiales importantes de l’origine des masses d’air durant les variations climatiques du Pléistocène.
Dans un deuxième temps, une analyse des caractéristiques de la glace annuelle de 4 lacs du nord de la Suède a été réalisée afin d’étudier le rôle de la couverture de glace sur les émissions de gaz à effet de serre. En effet, les lacs de ces régions contribuent fortement aux émissions de méthane durant la période d’eau libre et très peu d’études ont analysé la quantité de méthane emprisonnée dans la glace hivernale et relâchée au printemps. Ce projet nous a amené à établir une nouvelle classification des bulles dans la glace de lac basée sur leur contenu en méthane, leur origine, leur forme et leur densité. Il nous a également permis de montrer que plusieurs facteurs interviennent sur le contenu en gaz dans la couverture de glace :le système hydrologique, la variation de la pression atmosphérique, la variabilité des émissions et potentiellement la proximité des sédiments sont autant de facteurs qui déterminent le contenu en gaz. L’analyse de la composition des gaz a révélé que la composition observée dans la glace est sensiblement différente de celle observée durant les périodes d’eau libre. Nous avons également, pour la première fois, établit un budget des émissions de méthane relâchées par la fonte de la couverture de glace au niveau mondial.
Cette étude a été complétée par l’analyse des isotopes 13C des gaz des différents types de bulles de notre classification en collaboration avec l’Université d’Utrecht. Nous avons alors mis en évidence que la couverture de glace influence l’équilibre biogéochimique dans l’eau en favorisant l’oxydation du méthane en dioxyde de carbone.
Doctorat en Sciences
info:eu-repo/semantics/nonPublished
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Morandin, Lora A. "Bumble bee, Bombus impatiens, pollination of greenhouse tomatoes." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 2000. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape2/PQDD_0018/MQ58064.pdf.
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Schultz, Lisa. "Understanding the Greenhouse Effect Using a Computer Model." Fogler Library, University of Maine, 2009. http://www.library.umaine.edu/theses/pdf/SchultzL2009.pdf.
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Al-Shooshan, Ahmad A. "Greenhouse total water use analysis modeling and optimization /." Connect to resource, 1991. http://rave.ohiolink.edu/etdc/view?acc%5Fnum=osu1145451814.
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Gupta, Manish. "Restricting greenhouse gas emissions : economic implications for India /." New Delhi : Serials Publ, 2006. http://www.gbv.de/dms/zbw/522298486.pdf.
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Mendis, Asoka. "The greenhouse tomato industry in Delta, British Columbia." Thesis, University of British Columbia, 2007. http://hdl.handle.net/2429/257.
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This focus of this dissertation is the greenhouse tomato industry in Delta, British Columbia. Using a conceptual framework assembled from Regulation theory (including the concept of food regimes) and the political economy of agriculture, I explore the origins and development of the industry in Delta. I argue that sub-national regulation has historically played a pivotal role in the agricultural development of the region. The impact of such regulation on the greenhouse industry, however, is contingent upon the specific regime of accumulation. I make the case, for example, that regulation instituted in the early 20th century under an extensive regime of accumulation acts as a fetter on the industry under a post-Fordist regime of accumulation. Furthermore, I make the argument that the emergence and consolidation of Delta’s greenhouse tomato industry can best be understood through the deployment of the concept of food regimes. Thus the local industry can be seen as part of global trends in food production and consumption and which have come to characterise the third food regime.
In this thesis I also examine the ‘nature’ of the tomato and of greenhouse production. I demonstrate that, beginning in the mid-19th century, the tomato has been transformed into an input amenable to such industrial processes as canning. Using the conceptual tools offered by the political economy of agriculture, I further argue that the technique of greenhouse production is a result of the process of ‘appropriation’. That is, the discrete elements of the agricultural production process have been appropriated by industrial capital and reassembled as a technologically intensive system of plant production. However, and using the case study, I illustrate how this process of appropriation has created a new set of ‘natural’ obstacles within a fairly distinctive form of industrial agriculture.
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Al-Ismaili, Abdulrahim M. "Modelling of a humidification-dehumidification greenhouse in Oman." Thesis, Cranfield University, 2009. http://dspace.lib.cranfield.ac.uk/handle/1826/6568.
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The humidification-dehumidification (HD) greenhouse is a relatively new technology. In addition to the humidification process and cultivation normally present in greenhouses in arid countries, the HD greenhouse also integrates a dehumidification process. In these greenhouses, saline or brackish water is evaporated in the ordinary evaporative cooling pads (i.e. 1st humidifier) before passing through the main crop growing section. The air is further loaded with more moisture by passing it through a 2nd humidifier. This humidification process is then followed by a dehumidification process to condense as much water vapour as possible. The main purpose of the HD greenhouses is to find a cheap means of desalinating saline water for the sake of using the condensate for irrigation. Most of previous attempts to improve the performance of the HD greenhouses have used a trial-and-error approach. An alternative approach is to use simulation models. Due to the absence of such models, this research study aims at developing a simulation model capable of simulating the significant processes of the HD greenhouses. The developed model is an integration of three sub-models each of which simulates one element of the HD greenhouse. The simulated elements are humidifiers, cultivation area (i.e. microclimate) and dehumidifiers. The integrated model can be used for design and optimisation purposes. Because it was difficult to find an HD greenhouse where the accuracy of the integrated model can be tested, the three sub-models were tested separately. When the simulation results were confronted against the experimental results, a good accuracy was obtained for the three sub-models. It was found that the HD greenhouse model was able to predict the humidification rate with a good accuracy within the range of conditions used for calibration. The model was, then, used to simulate a hypothetical Quonset-type cucumber-cultivated greenhouse using weather data obtained from the site of the HD greenhouse in Oman. The simulation results were similar to the expected results.The applications and limitations of the HD greenhouse model are discussed in this study. Future investigations to further study and, if necessary, improve the accuracy of the HD greenhouse are highly recommended.
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Dinsmore, Kerry J. "Atmosphere-soil-stream greenhouse gas fluxes from peatlands." Thesis, University of Edinburgh, 2009. http://hdl.handle.net/1842/4040.
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Peatlands cover approximately 2-3% of the world’s land area yet represent approximately a third of the worlds estimated total soil carbon pool. They therefore play an important role in regulating global atmospheric CO2 and CH4 concentrations, and even minor changes in their ability to store carbon could potentially have significant effects on global climate change. Much previous research has focussed primarily on land-atmosphere fluxes. Where aquatic fluxes have been considered, they are often in isolation from the rest of the catchment and usually focus on downstream losses, ignoring evasion (degassing) from the water surface. However, as peatland streams have been repeatedly shown to be highly supersaturated in both CO2 and CH4 with respect to the atmosphere, they potentially represent an important pathway for catchment GHG losses. This study aimed to a) create a complete GHG and carbon budget for Auchencorth Moss catchment, Scotland, linking both terrestrial and aquatic fluxes, and b) understand what controls and drives individual fluxes within this budget. This understanding was further developed by a short study of C exchange at the peat-aquatic interface at Mer Bleue peatland, Canada. Significant variability in soil-atmosphere fluxes of both CH4 and N2O emissions was evident at Auchencorth Moss; coefficients of variation across 21 field chambers were 300% and 410% for CH4 and N2O, respectively. Both in situ chamber measurements and a separate mesocosm study illustrated the importance of vegetation in controlling CH4 emissions. In contrast to many previous studies, CH4 emissions were lower and uptake greater where aerenchymous vegetation was present. Water table depth was also an important driver of variability in CH4 emissions, although the effect was only evident during either periods of extreme drawdown or when the water table was consistently near or above the peat surface. Significant pulses in both CH4 and N2O emissions were observed in response to fluctuations in water table depth. Despite the variability in CH4 and N2O emissions and the uncertainty in up-scaled estimates, their contribution to the total GHG and carbon budgets was minor. Concentrations of dissolved CO2 in peatland drainage waters ranged from a mean of 2.88 ± 0.09 mg C L-1 in the Black Burn, Scotland, to a mean of 7.64 ± 0.80 mg C L-1 in water draining Mer Bleue, Canada. Using non-dispersive infra-red (NDIR) CO2 sensors with a 10-minute measurement frequency, significant temporal variability was observed in aquatic CO2 concentrations at the 2 contrasting field sites. However, the drivers of this variability differed significantly. At Mer Bleue, Canada, biological activity in the water column led to clear diurnal cycles, whereas in the Black Burn draining Auchencorth Moss, dilution due to discharge was the primary driver. The NDIR sensor data also showed differences in soil-stream connectivity both between the sites (connectivity was weak at Mer Bleue) and across the range of conditions measured at Auchencorth Moss i.e. connectivity increased during periods of stormflow. Compiling the results from both the terrestrial and aquatic systems at Auchencorth Moss indicated that the catchment was functioning as a net sink for GHGs (382 kg CO2-eq ha-1 yr-1) and a net source of carbon (143 kg C ha-1 yr-1). The greatest flux of GHGs was via net ecosystem exchange (NEE). Terrestrial emissions of CH4 and N2O combined returned only ~5% of CO2-equivalents captured by NEE to the atmosphere, whereas evasion of CO2, CH4 and N2O from the stream surface returned ~40%. The budgets clearly show the importance of aquatic fluxes at Auchencorth Moss and highlight the potential for significant error in source/sink strength calculations if they are omitted. Furthermore, the process based understanding of soil-stream connectivity suggests the aquatic flux pathway may play an increasingly important role in the source-sink function of peatlands under future management and climate change scenarios.
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Hunter, Stephen James. "Modelling Antarctic Ice Sheets under Greenhouse Earth Conditions." Thesis, University of Leeds, 2009. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.521464.
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Edwards, Kerri. "Greenhouse gas emissions from drip irrigated tomato fields." Thesis, McGill University, 2014. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=123327.
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Irrigation practices change the soil moisture in agricultural fields, and in turn influence the emissions of greenhouse gases. A two year field study was conducted to assess the emissions of CO2, CH4 and N2O from surface drip and subsurface drip irrigated tomato fields in Southwestern Ontario, Canada. Gas fluxes were obtained through the static chamber method, taking samples every 15 minutes over a one hour time period. Soil moisture and soil temperature were measured once per chamber per hour and used to help explain the gas emissions. A peak mean N2O flux at 405 µg N2O-N m-2 h-1 was observed from the five chambers in the surface drip irrigation treatment on July 8th, 2013, shortly following a rainfall event. Most N2O fluxes which occurred during the irrigated portion of the growing season were around 50 µg N2O-N m-2 h-1 in both treatments, water added here was less than some of the large rainfall where peaks occurred. Both the lowest CO2 mean treatment fluxes (12 mg CO2-C m-2 h-1) and highest (12 mg CO2-C m-2 h-1) were observed in the surface drip irrigation plots. Seasonal emissions of CO2 were significantly greater in surface drip plots than subsurface drip plots in 2013, but not in 2012, and this is likely attributed to soil temperature differences. Methane ¬fluxes were mainly negative, indicating that the soil is a sink, as opposed to a source for this gas. Generally, there was no significant difference in soil moisture between the types of drip system. Consequently, there were only a few days which showed significant differences between subsurface drip irrigation and surface drip irrigation treatments for the hourly collected gas fluxes throughout the two growing seasons. Overall, the use of subsurface drip irrigation or surface drip irrigation does not affect the emissions of greenhouse gases from the tomato fields in this study.Les techniques d'irrigation affectent l'humidité du sol dans les terres agricoles, ce qui affecte les émissions de gaz à effets de serre. Une étude sur le terrain d'une durée de deux ans a été menée dans le sud-ouest de l'Ontario au Canada afin de déterminer les émissions de CO2, CH4 et N2O de champs de tomates irrigués au goutte-à-goutte de surface et au goutte-à-goutte souterrain. Les flux de gaz ont été obtenus en prenant des échantillons à chaque 15 minute pour une durée d'une heure, en utilisant la méthode de chambre statique. L'humidité et la température des sols ont été mesurés et utilisés afin d'expliquer les émissions de gaz. La moyenne de flux de N2O a atteint un sommet de 405µg N2O-N m-2 h-1 dans le cas de l'irrigation au goutte-à-goutte de surface, peu de temps après un épisode de pluie. La majorité des flux de N2O qui se sont produits pendant le moment de la saison utilisant de l'irrigation était d'environ 50 µg N2O-N m-2 h-1 dans les deux traitements. La plus faible (12mg CO2-C m-2 h-1) et la plus haute (123mg CO2-C m-2 h-1) moyenne des flux des traitements ont toutes les deux été observées dans les champs irrigués au goutte-à-goutte de surface. Les flux de CH4 étaient principalement négatifs ce qui indiquent que les sols sont des puits, plutôt qu'une source de ce gaz. Une différence significative entre les flux des traitements a été démontrée seulement pour un nombre limité de jour parce que l'humidité des sols créée par les deux systèmes d'irrigation de goutte-à-goutte était similaire. Les émissions saisonnières de CO2 étaient significativement plus hautes dans le cas des champs irrigués au goutte-à-goutte de surface que les champs irrigués au goutte-à-goutte souterrain en 2013, mais pas en 2012, ce qui est probablement dû aux différences dans les températures des sols. Globalement, l'utilisation de l'irrigation au goutte-à-goutte de surface ou de l'irrigation au goutte-à-goutte souterraine n'a pas d'effet majeur sur les émissions de gaz des sols dans les champs de tomates.
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Fankhauser, Samuel. "Greenhouse economics and the costs of global warming." Thesis, University College London (University of London), 1994. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.302696.
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Leung, Wing Chi. "Modelling greenhouse gases in a general equilibrium model." Thesis, Massachusetts Institute of Technology, 1996. http://hdl.handle.net/1721.1/43724.
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Thesis (M. Eng.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 1997.Includes bibliographical references (leaves 51-52).
by Wing Chi Leung.
M.Eng.
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Edwards, Morgan Rae. "Greenhouse gas equivalency metrics for evaluating energy technologies." Thesis, Massachusetts Institute of Technology, 2017. http://hdl.handle.net/1721.1/112052.
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Thesis: Ph. D. in Engineering Systems, Massachusetts Institute of Technology, School of Engineering, Institute for Data, Systems, and Society, 2017.Cataloged from PDF version of thesis.
Includes bibliographical references (pages 127-137).
This thesis addresses a long-standing question about how to compare energy technologies that emit different types of climate forcers during their life cycles. This problem is challenging because these forcers have dissimilar lifetimes in the atmosphere, ranging from days (black carbon) to decades (methane, CH 4) to centuries or more (carbon dioxide, CO2 ). Efforts to reduce the climate impacts of energy use may involve a tradeoff between these short-and long-lived emissions. Equivalency metrics, which express emissions of one forcer (e.g., CH4 ) in units of another (typically CO2), are widely-used tools for comparing the climate impacts of emissions. These metrics allow climate impacts to be expressed on a single scale, but they require assigning a relative value to short- versus long-lived climate forcing. The equivalency metric approach is used in a large variety of applications, from technology evaluation to emissions trading. These applications almost universally rely on a single metric, developed as a placeholder over twenty-five years ago. This metric, the global warming potential (GWP), compares gases based on their radiative forcing impacts over a fixed time horizon (usually 100 years). The design of the GWP, including critically the time horizon over which emissions are compared, is largely arbitrary, yet it has enormous implications for comparing the climate impacts of energy technologies and other emissions sources. Despite the practical and political importance of equivalency metrics, the scientific literature has not produced a consensus on how to design or choose these metrics. To address this gap in the literature, this thesis develops a new conceptual and quantitative modeling approach to link equivalency metric design to global climate policy goals. This procedure involves (a) formulating a set of goal-inspired equivalency metrics, (b) testing metrics by simulating the results when they are applied in real-world contexts, and (c) selecting metrics based on multiple performance criteria. We highlight two dimensions of metric performance: climate performance (i.e., whether metric-based decisions meet climate policy goals) and energy performance (i.e., whether these decisions support energy use, for example during a technology transition). No metric performs optimally across all criteria, and this approach allows us to quantify these performance tradeoffs. The central result of the thesis is that climate policy goals can be used to inspire equivalency metric design, and these goal-inspired metrics address key shortcomings of the GWP(100). Specifically, under a policy to limit global temperature change to 2°C (where radiative forcing levels stabilize around mid-century), a shorter time horizon is essential. We find that applying the GWP(100) in this policy context can lead to radiative forcing overshoots in excess of two thirds of the remaining budget. One set of goal-inspired metrics addresses this concern by reducing the time horizon over which emissions are compared as a radiative forcing limit is approached (Chapter 2). These metrics increase the impact value placed on short-lived CH4 (relative to long-lived CO2 ) over time. We find that this design reduces the risks of overshooting radiative forcing limits, despite inherent uncertainty in the timeline for reaching these limits (Chapter 3). Relative to other metrics that lead to similar peak radiative forcing outcomes, these goal-inspired metrics allow more energy use early on, which can help enable technology transitions (Chapter 4). Applying these goal-inspired metrics to evaluate natural gas suggests that the mitigation benefits of this high-CH 4-emitting fuel will decrease significantly in the coming years. For example, under a radiative forcing limit consistent with a 2°C temperature change policy, the climate impact of natural gas electricity increases from 50% that of coal to 80% by mid-century (Chapter 2). Similar results apply to transportation fuels with high CH4 (or black carbon) emissions (Chapter 2, Chapter 5). This result draws into question large investments in technologies and long-lived infrastructure with high life cycle CH4 emissions - and provides a quantitative basis for calculating timelines to reduce the CH4 intensity of these technologies or transition to lower-emitting technologies. A bridging strategy, where technologies with high CH4 emissions are followed by those with lower emissions, permits greater overall energy consumption while meeting climate policy targets (Chapter 5).
by Morgan R. Edwards.
Ph. D. in Engineering Systems
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Hua, Shan. "Financial market evaluation of firms' greenhouse gas emissions." Thesis, University of Exeter, 2013. http://hdl.handle.net/10871/10522.
Full textAbstract:
Climate change has been influenced more by human activities now than previously. These influences are largely attributed to industries, whose activities can potentially produce enormous amounts of carbon dioxide and other greenhouse gases, and exacerbate the speed of climate change. This thesis examines how the financial markets evaluate corporations’ greenhouse gas emission performance. We consider various emission criteria, and distinguish between the better and worse performers in different emission policy regimes, including the US, the UK and the rest of the EU. The investigations have been conducted at three stages, presented in chapter 3, 4 and 5. Firstly, in chapter 3 we examine the carbon effects at the portfolio-level, where total return indices are our main concern. By adopting the long-short strategy, we report that investors in the UK and EU markets, can make an arbitrage profit at the lower cut-off levels, when applying various carbon screening policies and forming equally-weighted portfolios. However, no such profit opportunities can be achieved in the US market. We further consider the reason for such arbitrage opportunities, which is the link between corporate governance/management efficiency and different levels of carbon constraint. Secondly, in chapter 4, the carbon effects are investigated at firm-level, where firms’ financial market values act as the dependent variable. Our regression models are based on the Ohlson framework, which considers firms’ financial market value in relation to its accounting performance, and the ‘other information’, which in our case is the carbon emission performance. We find a significant relationship between the US firms’ values and their carbon emission performances; however, this relationship has been weakened for UK companies, and in fact becomes even unreliable for EU companies. Further, in order to explore the reason for this relationship, we have focused on energy efficiency and firms’ reputation that are associated with carbon reduction activities. The scale effects have also been discussed in this chapter, as the various deflators are adopted. Finally, in chapter 5, again at firm-level, cash flow expectation and cost of capital have been considered to possibly be the source that drives firms’ value. Cash flow expectation is measured at the short-, medium- and long- term, by profitability, earnings growth, and residual income growth rate, respectively. Two portfolios for each target parameters are constructed according to different carbon screening criteria at different cut-off levels, the differences between each pair of portfolios are then calculated and tested for significance. A sub-sample regression, which is based on the observations available from analysts’ earnings forecast, has been conducted for each of the three regimes. After matching the portfolio and regression results, we report that the implied cost of equity is only reduced for the less carbon emission firms, in regimes where more stringent carbon constraints are applied; whereas in regimes where less stringent carbon constraints exist, the less carbon emission firms have not gained any advantage through their implied cost of equity. Also, cash flow expectations indicate diverse outcomes for different time horizon and regimes. Furthermore, various market participants, such as governments, investors, distributors and clients etc, who could possibly influence firms’ carbon behaviour, have also been considered in association with their roles in reducing greenhouse gas emissions. Our work contributes to the existing literature through a wide ranging examination of major financial evaluation methods relating to emerging carbon emission issues.
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"Comparing greenhouse gasses." MIT Joint Program on the Science and Policy of Global Change, 2001. http://hdl.handle.net/1721.1/3568.
Full textAbstract:
Controlling multiple substances that jointly contribute to climate warming requires some method to compare the effects of the different gases because the physical properties (radiative effects, and persistence in the atmosphere) of the greenhouse gases are very different. We cast such indices as the solution to a dynamic, general equilibrium cost-benefit problem where the correct indices are the relative shadow values of control on the various substances. We find that use of declining discount rate, as recommended by recent research, suggests that the current physical-based indices adopted in international negotiations overestimate the value of control of short-lived gases and underestimates the value of control of very long-lived species. Moreover, we show that such indices will likely need to be revised over time and this will require attention to the process by which decisions are made to revise them and how revisions are announced.Includes bibliographical references (p. 18-19).
Abstract in HTML and technical report in PDF available on the Massachusetts Institute of Technology Joint Program on the Science and Policy of Global Change website (http://mit.edu/globalchange/www/)
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Ray, Jennie Boyd. "Search for the greenhouse." 2007. http://www.lib.ncsu.edu/theses/available/etd-11072007-155215/unrestricted/etd.pdf.
Full text
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Cheuk, William Wai Lun. "Sustainable vegetable greenhouse production through bio-conversion of greenhouse solid wastes and re-utilization." Thesis, 2003. http://hdl.handle.net/2429/15925.
Full textAbstract:
Current practices of handling greenhouse wastes are not the sustainable ways to conserve
agricultural lands and ground waters. This study developed a sustainable growing practice
in the vegetable greenhouse industry. Waste handling (shredding) and the biodegradable
plastics were investigated first. Then, different composting control algorithms and
substrate recipes were tested in both lab scale and pilot scale composting. With a good
control algorithm, composting of greenhouse wastes could reach the requirement for
Process to Reduce Further Pathogens, PFRP (55 OC for 3 days). Ammonia emission
might be a problem but it could be reduced by using air-recirculation or removed by a
biofilter with compost as medium. Recirculation cooling control was found to be a more
effective method, to maintain the process temperature below the set point, than any kind
of temperature feedback control. Less leachate and condensate were found from the
reactors with air recirculation control. Systems with air recirculation for cooling and
aeration showed higher degradation rates, and also more consistent moisture content of
the final compost.
Alder bark was found out to be a better choice of bulking agent than hemlock bark in
terms of better substrate structure, more carbon loss, less nitrogen loss, and higher
process temperature. Shredding was proven to be not necessary before composting of
prunings and it also helped minimizing the amount of leachate. Bulking agents (alder
bark) of about 20-30% (in weight) were found necessary for composting prunings. For year-end wastes, a ratio of 62% vines, 13% used sawdust and 25% alder bark was
recommended for in-vessel composting.
Using conventional management techniques in greenhouse tomatoes, a similar yield using
a 2:1 sawdust to amendment mix by could be achieved compared to conventional sawdust
medium. Significant reduction of crown and root rot disease caused by Fusarium
oxysporum f. sp. radicis- lycopersici in susceptible tomatoes was achieved by addition of
the greenhouse compost amendment to seedling plugs or blocks, and by mixing with the
sawdust medium. A mixture of 2:1 sawdust to amendment by volume was shown to be
effective. The reduction in disease resulted in 74% improved yield over a full growing
season under high disease pressure.Applied Science, Faculty of
Chemical and Biological Engineering, Department of
Graduate