Dissertations / Theses on the topic 'Ear temperature'
Create a spot-on reference in APA, MLA, Chicago, Harvard, and other styles
Consult the top 50 dissertations / theses for your research on the topic 'Ear temperature.'
Next to every source in the list of references, there is an 'Add to bibliography' button. Press on it, and we will generate automatically the bibliographic reference to the chosen work in the citation style you need: APA, MLA, Harvard, Chicago, Vancouver, etc.
You can also download the full text of the academic publication as pdf and read online its abstract whenever available in the metadata.
Browse dissertations / theses on a wide variety of disciplines and organise your bibliography correctly.
Nascimento, Vítor Rodrigues do. "Evaluation of thermometers for ear temperature measurement at the wards in a university hospital." Master's thesis, Faculdade de Ciências e Tecnologia, 2012. http://hdl.handle.net/10362/8480.
Full textSince mercury thermometers were banned due to environmental concerns, hospitals started to use electronic thermometers for measuring body temperature. Body temperature can be measured from different body parts, although the least invasive and quickest is preferred and therefore eardrum measurements are frequently taken. However, lately the staff feels that the taken measurements are not accurate. A new purchasing agreement for the purchase of these devices renders a good opportunity to study further the use of these devices at the wards of the university hospital, study their maintenance process, identify what performance is essential for the clinical usage, the parameters that are essential to measure and also identify ear thermometers in the market that can be used for comparative study. Temperature measurements were taken with the help of an infrared ear thermometer, Covidien Genius2, in its calibration blackbody device at the R&D department of the Huddinge Hospital in order to verify accuracy claims. This data were compared against other studies and measurements of other infrared ear thermometers devices, the Braun ThermoScan Pro 4000 and also a digital contact thermometer, Welch Allyn Suretemp Plus, applied to different body sites. Informal meetings also took place in order to get more information about the devices and to know where they were used and repaired. It was found that Genius2 measured temperature accurately when compared with a blackbody radiator. Regarding the Braun, it showed an accurate estimate of core temperature in comparison to invasive pulmonary artery catheter thermometry. Electronic tympanic thermometers proved to be a good replacement for conventional methods of thermometry. However, preventive maintenance should occur more often, since the devices are very fragile. Tympanic thermometers are generally very accurate instruments. Most likely, problems are not related to the thermometers themselves, they are possibly the result of an inadequate understanding of the limitations of ear thermometry.
Knox, Andrew Mark. "The Effect of Cooling the Head to Reduce Brain Temperature on Stress." Thesis, University of Canterbury. Psychology, 2013. http://hdl.handle.net/10092/8186.
Full textLehmuskallio, E. (Eero). "Cold protecting emollients and frostbite." Doctoral thesis, University of Oulu, 2001. http://urn.fi/urn:isbn:9514259882.
Full textWan, Margaret. "Assessment of occupational heat strain." [Tampa, Fla] : University of South Florida, 2006. http://purl.fcla.edu/usf/dc/et/SFE0001661.
Full textCherbuin, Nicolas, and n. cherbuin@anu edu au. "Hemispheric interaction: when and why is yours better than mine?" The Australian National University. Faculty of Science, 2006. http://thesis.anu.edu.au./public/adt-ANU20060317.135525.
Full textMOUNIER, CLAUDE. "Contribution a l'etude du coefficient de temperature des reacteurs a eau legere." Paris 11, 1993. http://www.theses.fr/1993PA112385.
Full textPillai, Rahul Radhakrishna. "Efficiency analysis of varying EGR under PCI mode of combustion in a light duty diesel engine." Thesis, Texas A&M University, 2008. http://hdl.handle.net/1969.1/86042.
Full textStrahl, Audra Lynne. "Characterization of temperature sensitive vaccinia virus mutants in the a3l and e6r complementation groups." [Gainesville, Fla.] : University of Florida, 2004. http://purl.fcla.edu/fcla/etd/UFE0005203.
Full textTypescript. Title from title page of source document. Document formatted into pages; contains 59 pages. Includes Vita. Includes bibliographical references.
RAYNAL, ROHAN SYLVIE. "Emulsions multiples eau/huile/eau encapsulant du mgso4 : etude des transferts de matiere a temperature ambiante et subambiante par analyse enthalpique differentielle, rheologie et conductimetrie." Paris 11, 1996. http://www.theses.fr/1996PA114807.
Full textSarangi, Asish. "Diesel low temperature combustion : an experimental study." Thesis, Loughborough University, 2012. https://dspace.lboro.ac.uk/2134/10192.
Full textSit, Ji-Jon 1975. "A low-power analog logarithmic map circuit with offset and temperature compensation for use in bionic ears." Thesis, Massachusetts Institute of Technology, 2002. http://hdl.handle.net/1721.1/16893.
Full textIncludes bibliographical references (p. 74-75).
This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.
Logarithmic map circuits are useful in many applications that require non-linear signal compression, such as in speech recognition and cochlear implants. A logarithmic current-mode A/D converter with temperature compensation and automatic offset calibration is presented in this paper. It employs a dual-slope, auto-zeroing topology with a 60 dB dynamic range and 300 Hz sampling rate, for capturing the envelope of speech signals in a bionic ear. Fabricated in a 1.5 [mu]m process, the circuit consumes only 1 [mu]W of analog power and another 1 [mu]W of digital power, and can therefore run for over 50 years on just a couple of AA batteries. At the current level of power consumption, we have proven that this design is thermal-noise limited to a 6-bit precision, and higher precision is possible only if we expend more power. As such, it is already useful for cochlear implants, as deaf patients can only discriminate 1 dB out of a 30 dB dynamic range in the auditory nerve bundles. For the purpose of using this circuit in other applications, we conclude with several strategies that can increase the precision without hurting the power consumption.
by Ji-Jon Sit.
S.M.
Hennion, Françoise. "Etude des fluctuations des signaux des capteurs thermohydrauliques dans les réacteurs à eau pressurisée." Grenoble 1, 1987. http://www.theses.fr/1987GRE10126.
Full textJAYASEELAN, VIDHYA SAGAR. "STUDY OF POLYCRYSTALLINE DIAMOND THIN FILMS GROWN IN A CUSTOM BUILT ECR PE-CVD SYSTEM." University of Cincinnati / OhioLINK, 2000. http://rave.ohiolink.edu/etdc/view?acc_num=ucin975513169.
Full textBuitrago, Villaplana Esther. "LCC and LCA for Low Temperature Heating Integrated with Energy Active Envelope Systems." Thesis, KTH, Energiteknik, 2020. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-277027.
Full textFönster har alltid betraktats som kylflänsar och de kan stå för mer än 25% av byggnadens kuvert. Av denna anledning spelar deras design och prestanda i bostäder en viktig roll för att reglera inomhusmiljön. Byggsektorn har investerat i bättre isoleringshölje system under de senaste decennierna för att minska värmeöverförings förlusterna och energiförbrukningen i hushållen. LOWTE är ett svenskt företag som är specialiserat på byggnadskomponenter med låg energi och på grund av alla dessa fakta har det nyligen utvecklat ett fönster med dubbelspalt och energi aktivt kuvert (EAW) för att förbättra energibesparing i byggnader. EAW är en fönster prototyp som integrerar låg temperatur värme och energi aktiva system som kommer att installeras på Testbed KTH i Stockholm (Sverige). Avfallsvärme från de nuvarande värmesystemen kommer att användas under hela driften. Sedan kommer en livscykelanalys (LCA) att genomföras för att utvärdera EAW med avseende pågenomförbarhet och kostnadseffektivitet innan denna implementering. Dessutom kommer en LCAjämförelse med andra två passiva fönstersystem att göras. Ett dubbelglasat och ett tredubbelt fönster representerar referenssystemet respektive en kompetent alternativ lösning. En känslighetsanalys för varje modell kommer att utvecklas för att ta hänsyn till flera scenarier och utvärdera vilka variabler som mest påverkar EAW-lönsamhet. Således skulle genomförbarheten för EAW studeras ur ett ekonomiskt och miljömässigt perspektiv. Simuleringarna av båda modellerna visar potentialen som EAW kan representera för det nuvarande värmesystemet i KTHs Live-In-Lab-lägenheter. Eftersom EAW är helt utsatt för de termiska förhållandena i rummet, atmosfären och den inre flödande luften; beror kostnadsbesparingar och minskad miljöpåverkan främst på värmeprestandan för hela systemet.
Wilson, Richard B. "An Embedded Atom Method Investigation Into the Lattice Dynamics of Metallic Surfaces." DigitalCommons@USU, 2011. https://digitalcommons.usu.edu/etd/1054.
Full textDOTSIKA, ELISSAVET. "Utilisation du geothermometre isotopique sulfate-eau en milieux de haute temperature sous influence marine potentielle : les systemes geothermaux de grece." Paris 11, 1991. http://www.theses.fr/1991PA112370.
Full textPauwels, Hélène. "Etude theorique et experimentale du comportement des elements traces lors des processus d'interaction eau-roche." Paris 7, 1988. http://www.theses.fr/1988PA077136.
Full textMalbéteau, Yoann. "Suivi des ressources en eau par une approche combinant la télédétection multi-capteur et la modélisation phénoménologique." Thesis, Toulouse 3, 2016. http://www.theses.fr/2016TOU30193/document.
Full textThis thesis aims to improve the spatio-temporal resolution of surface water fluxes at the land surface-atmosphere interface based on appropriate models that rely on readily available multi-sensor remote sensing data. This work has been set up to further develop (disaggregation, assimilation, energy balance modeling) approaches related to soil moisture monitoring in order to optimize water management over semi-arid areas. Currently, the near surface soil moisture data sets available at global scale have a spatial resolution that is too coarse for hydrological applications. Especially, the near surface soil moisture retrieved from passive microwave observations such as AMSR-E (Advanced Microwave Scanning Radiometer-EOS) and SMOS (Soil Moisture and Ocean Salinity) data have a spatial resolution of about 60 km and 40 km, respectively. In this context, the downscaling algorithm "DISaggregation based on Physical And Theoretical scale Change" (or DisPATCh) has been developed. The near surface soil moisture variability is estimate within a low resolution pixel at the targeted 1 km resolution based on an evapotranspiration model using LST (Land surface temperature) and NDVI (vegetation index) derived from MODIS (MODerate resolution Imaging Spectroradiometer) data. Within a first step, DisPATCh is applied to SMOS and AMSR-E soil moisture products over the Murrumbidgee river catchment in Southeastern Australia and is evaluated during a one-year period. It is found that the downscaling efficiency is lower in winter than during the hotter months when DisPATCh performance is optimal. However, the temporal resolution of DisPATCh data is limited by the gaps in MODIS images due to cloud cover, and by the temporal resolution of passive microwave observations (global coverage every 3 days for SMOS). The second step proposes an approach to overcome these limitations by assimilating the 1 km resolution DisPATCh data into a simple dynamic soil model forced by reanalysis meteorological data including precipitation. The original approach combines a variational scheme for root-zone soil moisture analysis and a sequential approach for the update of surface soil moisture. The performance is assessed using ground measurements of soil moisture in the Tensift-Haouz region in Morocco and the Yanco area in Australia during 2014. It is found that the downscaling/assimilation scheme is an efficient approach to estimate the dynamics of the 1 km resolution surface soil moisture at daily time scale, even when coarse scale and inaccurate meteorological data including rainfall are used. The third step presents a physically-based method to correct LST data for topographic effects in order to offer the opportunity for applying DisPATCh over mountainous areas. The approach is tested using ASTER (Advanced Spaceborne Thermal Emission Reflection Radiometer) and Landsat data over a 6 km by 6 km steep-sided area in the Moroccan Atlas. It is found that the strong correlations between LST and illumination over rugged terrain before correction are greatly reduced at ~100 m resolution after the topographic correction. Such a correction method could potentially be used as a proxy of the surface water status over mountainous terrain. This thesis opens the path for developing new remote sensing-based methods in order to retrieve water inputs -including both precipitation and irrigation- at high spatial resolution for water management
Bazer-Bachi, Adnane Robert. "Influence de la qualite d'une eau sur l'efficacite de la coagulation par le sulfate d'aluminium." Toulouse, INSA, 1986. http://www.theses.fr/1986ISAT0007.
Full textWheeler, Megan Caroline. "Parameters Influencing the Corrosion Protection Service Life of Epoxy Coated Reinforcing Steel in Virginia Bridge Decks." Thesis, Virginia Tech, 2003. http://hdl.handle.net/10919/9687.
Full textMaster of Science
Jada, Amane. "Etude de la structure et de la dynamique de microemulsions eau dans huile." Université Louis Pasteur (Strasbourg) (1971-2008), 1988. http://www.theses.fr/1988STR13101.
Full textZhang, Haiwa. "Experimental investigation of the phase diagram of ammonia monohydrate at high pressure and temperature." Electronic Thesis or Diss., Sorbonne université, 2019. https://accesdistant.sorbonne-universite.fr/login?url=https://theses-intra.sorbonne-universite.fr/2019SORUS410.pdf.
Full textThis thesis in experimental physics investigates the phase diagram of ammonia monohydrate (AMH) at high pressure (0
Chamoun, Marwan. "Modélisation, conception et étude expérimentale d’une pompe à chaleur industrielle à eau à haute température." Thesis, Lyon, INSA, 2012. http://www.theses.fr/2012ISAL0132/document.
Full textCurrently, improving energy efficiency becomes a main challenge for all industrial energy systems. This challenge involves an improved recovery of wasted heat generated by several industrial processes. Large energy savings and potential environmental benefits are associated with the use of industrial heat pump mainly at high temperature levels (>130°C) unavailable on the market. The development of high temperature heat pump using water vapor as working fluid is investigated. Technical problems restraining the feasibility of this industrial heat pump are surmounted by a specifically designed heat pump, the development of a new twin screw compressor and a new centrifugal compressor with magnetic bearings. A dynamic model of this heat pump is developed using Modelica and taking into account the presence of non-condensable gases in the machine. Detailed models of the compressors are developed based on their geometrical characteristics. Experimental results of the start-up phase have been presented showing the non-condensable purging process and the evolution of some parameters of the heat pump. These experimental results have been confronted to numerical simulations. Several scenarios of industrial processes for high-temperature heat recovery and heat upgrading are numerically simulated and analyzed based on energetic and exergetic studies. The heat pump model has been integrated to a distillation column showing the global energy savings and the environmental benefits of using this developed heat pump
Jaber, Lina. "Effets d’une restriction en eau chez des chèvres laitières en climat tempéré ou semi-aride." Thesis, Paris, AgroParisTech, 2014. http://www.theses.fr/2014AGPT0057.
Full textWater scarcity is a widespread problem in arid and semi-arid regions affecting goat production. This project aimed to study the effects of water restriction on goats from semi- arid and temperate regions. A first step consisted in reviewing the literature on the subject leading to two review manuscripts. In addition, research articles specifically addressing the topic of water restriction in sheep and goat were retained for the compilation of a large database that was used for a preliminary quantitative review (meta-analysis) with the aim of visualizing the effects of water restriction on different physiological and production parameters as reported in literature. The qualitative and quantitative reviews covered sheep and goat as species of interest. The subject of water stress was also addressed experimentally through two experiments on lactating and gestating Shami goats, respectively, raised under semi-arid environment and one experiment on lactating Saanen and alpine goats raised under temperate conditions. An intermittent watering regime of once every four days was imposed on the Shami goats for a period of around 1 month while the Saanen and alpine goats were subjected to a 15-hour overnight water restriction for two consecutive days. The effect of heat stress was also studied during a short episode of rise in ambient temperature from 19oC to 28oC in Saanen and alpine goats. Physiological data, key blood parameters and milk production and composition were recorded and analyzed.Lactating Shami goats subjected to intermittent watering showed increased serum osmolarity, urea, protein and albumin concentrations, denoting dehydration. Milk composition and production, and body weight were not affected by the treatment. However, in the gestating shami goats osmolarity was higher while insulin was lower indicating a possible state of negative energy balance. The kids born to the restricted goats had lower body weight at birth and at one month of age which warrants further research.Similarly, alpine and Saanen lactating goats, although subjected to a milder water restriction regime showed signs of dehydration reflected by the increase in albumin, urea, osmolarity and Na+. The goats were able to maintain body weight and milk production although milk urea and lactose increased under water restriction thus keeping milk isotonic with the blood.Heat stress had no effect on feed intake or on feed and water intake patterns in lactating Saanen and alpine goats. However, there was a 40% increase in water intake. Blood pCO2 decreased because the animals hyperventilated to reduce their body temperature, whereas rectal temperature increased. Milk production was not modified, but milk fat content decreased. Alpine goats drank more water per kg of dry matter intake than the Saanen. This could be explained either by their higher level of feed intake or by the effect of coat colour.The qualitative and quantitative reviews as well as the experimental part helped in determining the most prominent physiological effects of water restriction in small ruminants that are consistently reported namely: decrease in feed intake and milk production and weight loss, increase in osmolarity, urea, sodium, cholesterol and fatty acids and of milk components such as lactose and protein content. At the same time, understudied areas in relation to the effects of water restriction were identified such as water stress in interaction with other environmental factors, the comparison between breeds, the impact of individual variability, methods of water stress alleviation and impact on animal welfare, etc.As a conclusion, this project helped in condensing the relevant information on the effects of water stress on goats thus serving as an accessible resource for guiding future research and possibly goat producers, in facing water scarcity
Cabrera, Salcedo Andrea. "Modélisation du comportement mécanique "post-trempe", après oxydation à haute température, des gaines de combustible des réacteurs à eau pressurisée." Phd thesis, Ecole Nationale Supérieure des Mines de Paris, 2012. http://pastel.archives-ouvertes.fr/pastel-00705085.
Full textJean, Bruno. "Un polymere thermosensible a l'interface eau-air : interaction avec les tensioactifs et stabilisation de films minces." Paris 6, 2000. http://www.theses.fr/2000PA066230.
Full textTigges, Domini. "Nocivité des défauts sous revêtement des cuves de réacteurs à eau sous pressions." Paris, ENMP, 1995. http://www.theses.fr/1995ENMP0588.
Full textDi, Capua Francesco. "Sulfur-based denitrification of organic-deficient, acidic, low temperature and nickel contaminated waters in fluidized-bed reactors." Thesis, Paris Est, 2016. http://www.theses.fr/2016PESC1106.
Full textAutotrophic denitrification driven by reduced sulfur compounds is a promising and cost-effective biological nitrogen removal process, recommended for the treatment of organic-deficient waters, e.g. groundwater and several industrial wastewaters. Autotrophic denitrifiers utilize inorganic compounds as sources of energy and carbon. The lack of organics eliminates the need of post-treatments to remove excess organic carbon and limits the formation of harmful organic byproducts (e.g. trihalomethanes, THM), resulting in a clean and safe treatment also for drinking water. Wastewaters from mining and metal-finishing industry commonly feature low pH and temperatures as well as high heavy metal concentrations. Nitrogen removal from these waters is a technical challenge, since denitrifying bacteria usually thrives at circumneutral pH and ambient temperatures (20-30°C).The aim of this study was to develop a robust and efficient sulfur-based denitrification bioreactor process able to tolerate acidic pH, psychrophilic temperatures (< 20°C) and high nickel concentrations. The process was preliminary optimized in batch bioassays investigating the influence of sulfur source, i.e. thiosulfate (S2O32-) and biogenic and chemically synthesized elemental sulfur (S0), S0 particle size (powder and lentils), denitrifying culture (pure and mixed cultures of Thiobacillus) and temperature (6-30°C) on denitrification kinetics. The use of S2O32- and a pure culture of Thiobacillus denitrificans resulted in the highest denitrification rates. Biogenic S0 was tested for the first time as electron donor for autotrophic denitrification, showing 1.7-fold faster NO3- removal than that achieved with chemically synthesized S0 powder. The rates of thiosulfate-driven denitrification exponentially increased with temperature, being modeled according to the Arrhenius equation with an apparent activation energy Ea of 76.6 kJ/mol and a temperature coefficient Q10 of 3.0.Fluidized-bed reactors (FBRs) were used to investigate continuous thiosulfate-driven denitrification under decreasing feed pH (5.25-7.00) and temperatures (3-20°C). Denitrification efficiencies > 99% were observed at feed and effluent pH as low as 5.75 and 5.30, respectively. At lower feed pH values, the denitrification activity rapidly decreased due to an inorganic carbon deficiency. The addition of a carbonation unit providing CO2 as supplemental carbon source to the FBR biofilm allowed complete denitrification even at a pH of 4.75. In the same FBR, high-rate (up to 3.3 kg N-NO3-/m3 d) thiosulfate-driven denitrification was maintained at temperatures as low as 3°C. The impact of two Ni compounds, i.e. NiEDTA2- and NiCl2, on sulfur-based denitrification was investigated in a parallel FBR at 20 (±2)°C and feed Ni concentrations in the range of 5-200 mg Ni/L. Preliminary batch bioassays were carried out to assess Ni and free EDTA toxicity on sulfur-based denitrification. In batch bioassays, 25-100 mg Ni/L of NiCl2 inhibited NO3- removal by 7-16%, whereas no inhibition was observed with NiEDTA2-. Free EDTA inhibited sulfur-based denitrification at concentrations exceeding 100 mg/L. Both Ni compounds showed no detrimental effects on sulfur-based denitrification in FBR at the tested concentrations. Nickel mass balance, solid-phase characterization and thermodynamic modeling revealed that nickel precipitates were mostly washed out with the effluent, due to the slow Ni precipitation kinetics and high upflow velocities in the FBR. Nickel phosphate, sulfide and oxide were indicated as the main nickel precipitates and were mostly amorphous.FBRs were shown to be powerful and robust biofilm systems for nitrogen removal under acidic pH, psychrophilic temperatures and high nickel concentrations. The results of this study are of great interest for the treatment of NO3- contaminated ground and mining waters in cold regions (e.g. Canadian and Scandinavian regions) as well as acidic and heavy-metal-laden wastewaters
Oh, Minseok. "Growth kinetics of intermetallic phases in the Cu-Sn binary and the Cu-Ni-Sn ternary systems at low temperatures." access full-text online access from Digital Dissertation Consortium, 1994. http://libweb.cityu.edu.hk/cgi-bin/er/db/ddcdiss.pl?9513132.
Full textMoeglen, Magali. "Modification de la réactivité de surface d'un alliage base nickel afin de limiter le relâchement du nickel en milieu primaire des réacteurs à eau pressurisée." Thesis, Université Grenoble Alpes (ComUE), 2015. http://www.theses.fr/2015GREAI099/document.
Full textSteam generator tubes in pressurized water reactors (PWR) are made of nickel based alloy and represent nearly 75 % of the primary coolant loop surface. Due to generalized corrosion phenomena, nickel cations are released in the primary loop water. After neutron flux exposure in the reactor core, nickel cations can turn into radioactive products, such as 58Co. If carried through the circuit, these radioactive products precipitate and contaminate the loop, making maintenance more difficult.The present study goal is to form a very protective scale on the Alloy 690 surface by a pre-oxidation treatment performed at 700 °C. The impact of different parameters such as oxygen partial pressures of the gaz used during high temperature oxidation (low P(O2)=10 -6 bar or high P(O2)=0.2 bar) and the initial surface state of the sample (cold-worked or surface roughness) is studied. To minimize nickel cation release, the scale obtained must be continuous, homogeneous, rich in chromium and nickel free. The oxidation kinetics, studied using thermogravimetric analysis (TGA), show the existence of parabolic law independent of P(O2). The sample's surface aspect, observed using scanning electron microscopy (SEM), is similar for all P(O2). Top views show a preferential chromium oxidation along the grain boundaries and the formation of a chromium rich oxide scale, confirmed by X-ray photoelectron spectroscopy (XPS) and glow discharge optical emission spectrometry (GDOES); cross sectional views of the material exhibit holes beneath the oxide corresponding with the alloy's grain boundaries. The latter observation and an inert marking test with gold plots suggest a cationic growth of the oxide scale. X-ray diffraction (XRD) indicates the presence of chromia (Cr2O3) for low and high P(O2). For low P(O2), a Mn and Cr spinel is observed near the outer surface. For higher P(O2), a similar spinel layer is made up of Ni, Fe, Mn and Cr.Pretreatment conditions set to be applied on alloy 690 can be proposed thanks to the data collected. Samples, pretreated that way, are tested in simulated primary medium water and their nickel release is clearly cropping compared to non-thermaly-treated samples
VERMOYAL, JEAN-JEROME. "Contribution a l'identification des processus cinetiquement limitants de l'oxydation des alliages de zirconium caracterisation en electrochimie des solides des films d'oxyde formes a haute temperature." Université Joseph Fourier (Grenoble), 2000. http://www.theses.fr/2000GRE10077.
Full textHasni, Abdellatif. "Etude des principales proprietes chimiques des solutions eau-chlorure de magnesium : application a la comprehension des phenomenes de corrosion sous contrainte de l'acier inoxydable austenitique 17-12-mo." Paris 6, 1988. http://www.theses.fr/1988PA066287.
Full textThomas, Anthony. "Transfert d'eau et de chaleur dans une pile à combustible à membrane : mise en évidence expérimentale du couplage et analyse des mécanismes." Thesis, Université de Lorraine, 2012. http://www.theses.fr/2012LORR0143/document.
Full textProton exchange membrane fuel cells (PEMFC) make it possible to convert efficiently chemical energy into electricity. For this, hydrogen is oxidized at one of the electrodes of the cell, created protons pass through the electrolyte (membrane) while electrons flow across the external circuit provide the electrical energy. All these elements recombine at the second electrode, with oxygen, to produce water. Performance is not perfect within a cell and a part of the reactants energy is also degraded as heat. Despite recent advances, the large scale commercialization of PEMFC is still hampered by durability issues, some of them being related to water and thermal management. In order to quantify the thermal behavior and its effect on the water transport, a fuel cell has been instrumented for the electrodes temperature, water and heat fluxes measurement. The results show that high temperature gradients (up to about 30 K/mm) can exist in a cell operating under standard conditions. It was observed a clear influence of the temperature field in the cell on the water transport. Water flows towards the coldest part of the cell (usually the channels), passing through the porous layers in vapor phase in our experimental conditions
Moreira, Sílvia Alexandra Monteiro. "Hyperbaric storage of soup and comparison with refrigeration." Master's thesis, Universidade de Aveiro, 2014. http://hdl.handle.net/10773/13737.
Full textThe aim of this work was to investigate if hyperbaric storage, using high hydrostatic pressure, is effective in delaying ready-to-eat food products microbial and physicochemical spoilage allowing extending its shelf-life, with no need for refrigeration. Inicially, the hyperbaric storage of a ready-to-eat carrot soup was studied and compared to refrigeration. Soup was stored at diferente time (4 and 8 h), temperature (4, 25 and 30 ºC), and pressure (0.1, 100 and 150 MPa) conditions. In addition, were also performed tests in an industrial equipment with two real commercial products, Caldo verde and Bacalhau com natas that were stored for 12 h at different pressures (50, 100 and 150 MPa) at room temperature (~21 ºC). For both cases, microbial loads (total aerobic mesophiles, Enterobacteriaceae and yeast and moulds) and physicochemical parameters such as pH, titratable acidity, reducing sugars and colour, were compared with the controls at atmospheric pressure at the same temperature. Hyperbaric storage resulted in similar to better results when compared to refrigeration, since 100 MPa resulted in microbial growth inhibition, while for storage under 150 MPa microbial inactivation occured. Higher pressure (150 MPa) and a longer storage period (8 h for laboratorial scale, and 12 h for the tests in the industrial equipment) resulted in more pronounced microbial growth inactivation. Total aerobic mesophiles were found to be the less susceptible microorganisms to hyperbaric storage, compared to Enterobacteriaceae and yeast and moulds. Concerning the physycochemical parameters, storage under pressure, generally, was able to maintain the values similar to refrigeration. Therefore, hyperbaric storage with no need for temperature control seems to be a possible new preservation methodology, and an alternative to refrigeration.
O principal objectivo deste trabalho foi estudar os efeitos da aplicação da alta pressão hidrostática e se esta é eficaz no armazenamento de alimentos prontos a consumir, de modo a evitar a sua deterioração a nível microbiológico e fisico-quimico, permitindo assim o aumento do seu prazo de validade, sem necessidade de refrigeração. O armazenamento sob alta pressão foi inicialmente estudado em sopa de cenoura comercial e comparado com o armazenamento em refrigeração. A sopa foi armazenada em diferentes condições de tempo (4 e 8 h), temperatura (4, 25 e 30 ºC) e pressão (0.1, 100 e 150 MPa). Foi ainda realizado um estudo à escala industrial, onde se armazenaram dois produtos comerciais reais, Caldo verde e Bacalhau com natas, durante 12 h, sob diferentes pressões (50, 100 e 150 MPa) à temperatura ambiente (~21 ºC). Em ambos os estudos compararam-se, com os respetivos controlos à pressão atmosférica, as cargas microbianas (mesófilos totais, Enterobacteriaceae e bolores e leveduras) e alguns parâmetros fisico-químicos como o pH, acidez titulável, conteúdo em açúcares redutores e cor. O armazenamento sob alta pressão levou a resultados semelhantes ou melhores que a refrigeração, uma vez que foi visível uma inibição do crescimento microbiano para 100 MPa e ainda uma inativação microbiana para 150 MPa. A pressão mais elevada (150 MPa) e o período de estudo mais longo (8 h na escala laboratorial e 12 h na escala industrial) resultaram numa inactivação microbiana mais acentuada. Os mesófilos totais foram, dos microoganismos estudados, os menos susceptiveis à pressão. No que concerne aos parâmetros fisico-químicos analisados, o armazenamento sob alta pressão resultou, de forma geral, em valores semelhantes à refrigeração. Portanto, o armazenamento de alimentos prontos a consumir sob alta pressão, sem necessidade de controlo de temperatura, parece ser uma possível alternativa à refrigeração no que toca à conservação destes alimentos.
Kielbassa, Janice. "Mathematical modelling of temperature effects on the life-history traits and the population dynamics of bullhead (Cottus gobio)." Thesis, Lyon 1, 2010. http://www.theses.fr/2010LYO10181.
Full textWater temperature plays a key role in the life cycle of fish. Therefore, increasing temperatures due to the expected climate change may have a strong impact on growth, fecundity and survival. The goal of this thesis is to model the impact of temperature on the life-history traits of a bullhead population (Cottus gobio) in order to make predictions both at individual and at population level. The models developed here are calibrated on experimental field data from a population living in the Bez River network (Drôme, France). First, a new back-calculation model is derived that can be used to compute individual fish body lengths at earlier ages from capture data. Next, a growth model is proposed that incorporates the water temperature and can be used to predict the mean length at a given age and temperature. Finally, the population is modelled as a whole by linking all life-history traits to temperature. For this purpose, a spatialised time- and temperature-dependent Leslie matrix model structured in age classes was used to predict the population dynamics under different temperature scenarios
Liu, Na. "Microfluidique supercritique pour la compréhension des systèmes CO2 / eau sous pression et en température : Application à la gestion durable de la filière CO2." Phd thesis, Université Sciences et Technologies - Bordeaux I, 2013. http://tel.archives-ouvertes.fr/tel-00986265.
Full textPangaribuan, Charles. "Etude theorique d'un insolateur mixte utilisant l'eau et l'air comme fluides caloporteurs." Paris 6, 1988. http://www.theses.fr/1988PA066462.
Full textGuenot, Benoit. "Etude de matériaux catalytiques pour la conversion électrochimique de l'énergie Clean hydrogen generation from the electrocatalytic oxidation of methanol inside a proton exchange membrane electrolysis cell (PEMEC): effect of methanol concentration and working temperature Electrochemical reforming of Dimethoxymethane in a Proton Exchange Membrane Electrolysis Cell: a way to generate clean hydrogen for low temperature fuel cells." Thesis, Montpellier, Ecole nationale supérieure de chimie, 2017. http://www.theses.fr/2017ENCM0004.
Full textHydrogen is a promising energy vector, particularly for energy storage from intermittent energy sources such as solar or wind. The development of its production methods and its electrochemical conversion represents a major challenge in the context of energy transition in which we live nowadays. Fuel cells and electrolyzers using PEM technology (Proton Exchange Membrane) are mature electrochemical energy conversion systems, while reversible systems capable of performing both functions – unitized regenerative fuel cells – are still in the early stage of development. Their main technological bottleneck is the design of a bifunctional oxygen electrode. The catalytic materials used in these systems are mainly noble metals and it is necessary to reduce as much as possible their loading in the electrodes to decrease the system cost. Three complementary aspects have been developed during this thesis. On the one hand, iridium and ruthenium oxides have been prepared by hydrothermal treatment in order to catalyze the oxygen evolution under electrolyzer operation. On the other hand, platinum-based catalysts supported on non-carbonaceous materials, especially titanium nitride, have been synthesized by colloidal routes, in order to catalyze the oxygen reduction under fuel cell operation. The combination of these materials is the first step towards the design of a bifunctional oxygen electrode. The third topic focuses on the production of hydrogen and proposes an alternative to the oxidation of water. The electrochemical oxidation of organic compounds such as methanol or dimethoxymethane using platinum and ruthenium based catalysts allows producing clean hydrogen with a lower electrical energy consumption compared to the electrolysis of water
Dos, Ramos Catarino Ana Isabel. "Temperate and cold water sea urchin species in an acidifying world: coping with change?" Doctoral thesis, Universite Libre de Bruxelles, 2011. http://hdl.handle.net/2013/ULB-DIPOT:oai:dipot.ulb.ac.be:2013/209914.
Full textResponses of marine organisms to environmental hypercapnia, i.e. to an excess of CO2 in the aquatic environment, can be extremely variable and the degree of sensitivity varies between species and life stages. Sea urchins are key stone species in many marine ecosystems. They are considered to be particularly vulnerable to ocean acidification effects not only due to the nature of their skeleton (magnesium calcite) whose solubility is similar or higher than that of aragonite, but also because they lack an efficient ion regulatory machinery, being therefore considered poor acid-base regulators. Populations from polar regions are expected to be at an even higher risk since the carbonate chemical changes in surface ocean waters are happening there at a faster rate.
The goal of this work was to study the effects of low seawater pH exposure of different life stages of sea urchins, in order to better understand how species from different environments and/or geographic origins would respond and if there would be scope for possible adaptation and/or acclimatization.
In a first stage we investigated the effects of ocean acidification on the early stages of an intertidal species from temperate regions, the Atlantic Paracentrotus lividus sea urchin, and of a sub-Antarctic species, Arbacia dufresnei. The fertilization, larval development and larval growth were studied on specimens submitted through different pH experimental treatments. The fertilization rate of P. lividus gametes whose progenitors came from a tide pool with high pH decrease was significantly higher, indicating a possible acclimatization or adaptation of gametes to pH stress. Larval size in both species decreased significantly in low pH treatments. However, smaller A. dufresnei echinoplutei were isometric to those of control treatments, showing that size reduction was most likely due to a slower growth rate. In the pH 7.4 (predicted for 2300) treatment, P. lividus presented significantly more abnormal forms than control ones, but A. dufresnei did not. The latter does not seem to be more vulnerable than temperate species, most likely due to acclimatization/adaptation to lower pH seasonal fluctuations experienced by individuals of this population during spring time.
In a second stage, adult physiological responses of P. lividus and A. dufresnei to low pH seawaters were studied. Intertidal field P. lividus specimens can experience pH fluctuations of 0.4 units during low tidal cycles, but their coelomic fluid pH will not change. During experimental exposure to low pH, the coelomic fluid (extracellular) pH of both species decreased after weeks of exposure to low seawater pH. However, it owned a certain buffer capacity (higher than that of seawater) which did not seem to be related to passive skeleton dissolution. In laboratory studies, the feeding rate of P. lividus, the RNA/DNA ratio (proxy for protein synthesis and thus metabolism) of both the gonads and the body wall of the studied species and the carbonic anhydrase activity in the body wall (an enzyme involved in calcification and respiratory processes) of A. dufresnei did not differ according to seawater pH. The same was true for spine regeneration (a proxy for calcification) of both species. This shows that both P. lividus and A. dufresnei are able to cope when exposed to mild hypercapnia (lowest investigated pH 7.4) for a mid-term period of time (weeks). In a different set of experiments, pH effects were tested on P. lividus individuals together with two temperatures (10ºC and 16ºC). The pH decrease of the coelomic fluid did not vary between temperatures, neither did its buffer response. The oxygen uptake rates of P. lividus (as a proxy for global metabolic state of the whole organism) increased in lower pH treatments (7.7 and 7.4) in organisms exposed to lower temperatures (10ºC), showing that this was upregulated and that organisms experienced a higher energetic demand to maintain normal physiological functions. For instance, gonad production (given by the RNA/DNA ratio) was not affected neither by temperature, nor pH.
Finally, possible morphological and chemical adaptations of cidaroid (“naked”) spines, which are not covered by epidermis, to low magnesium calcite saturation states were investigated. Deep sea field specimens from the Weddell Sea (Antarctica), Ctenocidaris speciosa were studied. Cidaroid spines have an exterior skeleton layer with a polycrystalline constitution that apparently protects the interior part of the monocrystaline skeleton, the stereom (tridimensional magnesium calcite lattice). The cortex of C. speciosa was by its turn divided into two layers. From these, it presented a thicker inner cortex layer and a lower Mg content in specimens collected below the aragonite saturation horizon. The naked cortex seems able to resist to low calcium carbonate saturation state. We suggest that this could be linked to the important organic matrix that surrounds the crystallites of the cortex.
Some echinoid species present adaptive features that enable them to deal with low pH stresses. This seems to be related to the environmental conditions to which populations are submitted to. Therefore, organisms already submitted to pH daily or seasonal fluctuations or living in environments undersaturated in calcium carbonate seem to be able to cope with environmental conditions expected in an acidified ocean. Under the realistic scenario of a decrease of ca. 0.4 units of pH by 2100, sea urchins, and echinoderms in general, appear to be robust for most studied processes. Even thought, this general response can depend on different parameters such as exposure time, pH level tested, the process and the life stage considered, our results show that there is scope for echinoids to cope with ocean acidification.
Doctorat en Sciences
info:eu-repo/semantics/nonPublished
Dautriche, Bastien. "Développement d’un procédé de traitement industriel des eaux salées, chimie et génie du procédé." Thesis, Université Paris-Saclay (ComUE), 2016. http://www.theses.fr/2016SACLC030.
Full textThis work is a contribution to the development of an innovative desalination process by solvent extraction. The regeneration of the organic phase is achieved by desextraction of the salt at high temperature. Isotherms of distribution of NaCl, Na2SO4 and MgCl2 at 20 40 60 and 80°C were obtained. A stoichiometry able to account for their shapes was suggested and the associated equilibrium constants were determined. The extraction enthalpies were deduced from the variation of the constants with temperature.Non ideality in the aqueous phase was modeled with the Pitzer equations, simplified with the specific interaction principle. A thermodynamic correction to account for mixed salts effect in the organic phase was adjusted on binary data (NaCl, Na2SO4) at 20 40 and 60°C.Mechanical (viscosity, density) and thermal (specific heat, thermal conductivity) properties of the organic phase were characterised from 20 to 80°C. The interfacial tension was obtained at 20°C with pure water and filtrated natural seawater. The overall solubility of the solvant in water was measured. A prototype of the process with two extraction columns with a packed bed of 4 meters was tested. The HTU obtained were compared with a numerical model based on the classical stagewise backflow model expanded by a thermal balance
Choffel, Quentin. "La différenciation des masses d'eau à l'intérieur de l'étang : stratification verticale, zonation horizontale, bilan thermique et centre thermique." Thesis, Orléans, 2019. http://www.theses.fr/2019ORLE1167.
Full textPonds are at the heart of environmental issues in terms of quality and quantity of water resources. Temperature is an effective indicator in these measurements because of its reactivity and the ability to diffuse the most downstream. The pond is often considered as a black box in studies and the knowledge of its thermal functioning should be the first element in its quantification. In this study, the inclusion of volumes in the thermal analysis of the 1,137,181 original hourly thermal data, through the heat budget, allows to measure and quantify the whole behavior of the ponds, distinct from that of the lakes. The heat budget is a synthetic indicator of all the factors that bring and extract calories from the environment and can be used in its primary objective to measure calorific exchanges within the water body and between the water body and the river environment. The spatial heterogeneity in the zonal aspect of the pond is influenced by the effect of the driving force of the wind or the surrounding environment, the presence of shade or hydrological inputs. A new indicator, the heat center, has been created, taking into account three-dimensional variations in the heat balance, stratification and stability of several areas of the pond in order to quantify the dissociation of water masses within the water body. The integration of thermal zoning opens up new management opportunities to reduce the thermal impact of the pond downstream or to promote the development of certain heat-sensitive fish species. From meteorological data it is possible to anticipate areas of heat expansion whose differences can be significant, measured at more than 3°C on a very small pond related to the shading effect, or at more than 10°C between two sectors of a large multi-block pond under the influence of winds
Mora-Perez, José-Luis. "Modélisation de l'énergie thermique véhiculée par des jets vapeur d'eau-sodium liquide." Poitiers, 1988. http://www.theses.fr/1988POIT2329.
Full textDouss, Néjib. "Etude experimentale de cycles a cascades a adsorption solide." Paris 7, 1988. http://www.theses.fr/1988PA077052.
Full textWouters, Yves. "Oxydation thermique des métaux dans la vapeur d'eau : cas du nickel et du titane." Grenoble INPG, 1996. http://www.theses.fr/1996INPG0056.
Full textAbada, Fella. "Transport d'humidité en matériaux poreux en présence d'un gradient de température : caractérisation expérimentale." Université Joseph Fourier (Grenoble), 1994. http://www.theses.fr/1994GRE10135.
Full textRoy, Romain. "Distribution spatiale et activité des poissons en milieu lacustre - Impacts des facteurs environnementaux à partir d'une approche multi-échelle. Application à la retenue des Bariousses." Thesis, Aix-Marseille, 2014. http://www.theses.fr/2014AIXM4326/document.
Full textAquatic ecosystem functioning in human-impacted environments is highly dependent of its uses; in consequence, the environment of biological communities is generally fluctuating. Studying the link between environment and organism in fluctuating environments is generally more complex compared to steady environments. The main objective of this work was to better understand how fish populations respond to environmental modifications in a reservoir affected with water level fluctuations (WLF), the Bariousses’s reservoir located on the Vézère River.A multiscale approach was used with different biological (community and individual) and temporal (annual and daily cycles) scales. A special attention was given to the littoral zone as it plays a key role for lake fish communities and since it is strongly affected by WLF. This work is divided in 4 parts. The first part presents the characteristics of the study site and the second part describes the impact of WLF on the studied habitats using a mapping of the littoral zone. The consequences of hydrological stress through the changes in habitat conditions were also analyzed as well as the effects of water temperature and photoperiod. The third part shows the effect of the temporal variability of environmental conditions induced by WLF on the composition of the littoral fish community (sampled by electrofishing). The fourth part presents an innovative positioning system acoustic telemetry (Vemco Positioning System) that was used to study the impact of WLF at the individual scale by analyzing the behavior of 90 individuals from three different fish species (pikeperch, pike and perch) with a satisfactory accuracy (average error of 3.3 m after filtration).The results of this work showed that WLF induced a temporal variability of the littoral zone surface and volume. In addition, a gradual decrease of the structural complexity of littoral habitats was associated with lower water level inducing a trend to homogenization (dominance of thinner substrates without vegetation). Despite these changes in habitats conditions induced by WLF, littoral fish community did not show any clear change in composition. High inter-individual variability of behavioral responses was observed in response to environmental fluctuations, but the temperature and photoperiod were the two major structural parameters controlling fish activity and spatial distribution. Water level affected a part of the fish population since more individuals attended the littoral zone and were less mobile when available habitats were more complex (with a high water level). These results allowed us to suggest some ideas for the management of water levels in the studied reservoir focused on the fish population
Dehaoui, Amine. "Viscosité de l'eau surfondue." Thesis, Lyon 1, 2015. http://www.theses.fr/2015LYO10172/document.
Full textWater is an omnipresent liquid, indeed secrets of water are uncountable. In the water case, the behaviour of many thermodynamical and dynamicalquantities is very different from other standard liquids. This difference is more important in the supercooled state. In this thesis we focus on the viscosity of the heavy and light water into the supercooled state at atmospheric pressure. To do this we use the differential dynamic microscopy method. We were able to measure the viscosity to -34 C for light water and -25°C for heavy water. These viscosity measurements correlated to measurements of self-diffusion coefficient allowed us to confirm the existence of a so-called anomaly violation Stokes-Einstein
Brossard, Maxime. "Influence de l'eau (vapeur, liquide) et du régime d'oxydation sur la dégradation de revêtements alumino-formeurs sur superalliage à base nickel." Thesis, La Rochelle, 2014. http://www.theses.fr/2014LAROS018/document.
Full textUpon service, aero-turbine blades (nickel-based superalloys) are submitted to high temperature degradation that may alter their structural properties. The oxidizing atmospheres are particularly complex (O2, H2O, CO2, SO2, NOx…) with variable water vapour contents as function of the engine regime and the atmospheric conditions (clouds, rain, relative humidity of air). These substrate materials are protected by alumina-forming coatings to improve their oxidation resistance, while additional thermal barrier coatings insulate the hottest parts. This PhD project aims at studying the effect of water (vapour, liquid) on the degradation of conventional and new coatings (Al slurry, electrodeposited CeO2) developed at the LaSIE laboratory under different oxidation regimes (isothermal and cyclic). An approximation to service conditions was proposed through an original methodology in which several oxidation and post-ageing conditions for different oxidation ranges (hot, upon cooling, at room temperature) were performed. The experiments showed little effect of water vapour mixed with air at 1100°C in isothermal conditions, in particular when the alumina scale grew over the surface. In contrast, water-containing environments at room temperature (relative humidity, water drops) increased the spallation of the oxide scales above a critical threshold time. Cyclic oxidation with water cooling provoked in turn, a catastrophic failure of the aluminide coatings by a mechanism involving thermal fatigue and pitting corrosion
Segond, Guillaume. "Etudes des couplages thermohydrauliques en régime variable d'un système thermique avec stockage : application à la production d'eau chaude sanitaire à partir de la valorisation d'une source de chaleur basse température." Thesis, Aix-Marseille, 2015. http://www.theses.fr/2015AIXM4722.
Full textThe work presented here aims to study and optimize the energy efficiency of a heat pump water heater coupled with a sensible heat storage. The resource used consists of heat recovery from exhaust air of a collective type of housing. The challenge is to characterize the conditions in which the system is capable of ensuring the needs with performance required when the boundary conditions are very volatile. Functionally, the system should be as simple as possible from the viewpoint of its hydraulic configuration and its control strategy.For this study, we developed a TRNSYS numerical model to simulate and analyze different scenarios and thermal hydraulic couplings between the system components. In parallel with this modeling approach, we designed and implemented an experimental set up with realistic scale to validate the model over a wide range of operating conditions.The analysis of the results, including the nature of flows within the storage tank, highlighted the major influence on a number of parameters on the system performance. In particular, the robust performance in the face of significant fluctuations of the boundary conditions can be ensured through appropriate control strategy.This study eventually led to propose a model for the design of the system that takes into account the most relevant parameters for the control strategy
Rozen-Rechels, David. "Patrons et optimisation des comportements de thermo-hydrorégulation dans un paysage hétérogène Water restriction in viviparous lizards causes transgenerational effects on behavioral anxiety and immediate effects on exploration behavior When water interacts with temperature: Ecological and evolutionary implications of thermo‐hydroregulation in terrestrial ectotherms." Thesis, Sorbonne université, 2019. http://www.theses.fr/2019SORUS345.
Full textActual climate changes drive modifications of the thermal and water landscapes where live organisms. Thermoregulation in ectotherm species mostly rely on behavioral adjustments. These adjustments buffer the negative effects of these environmental changes on the physiology and the performances of the individuals. However, too few studies focused on the costs of changes in the water environment on thermoregulation behaviors. The main objective of this thesis is to highlight behavioral patterns involved in the joint regulation of body temperature and water balance, hereafter called thermo-hydroregulation behaviors, which would be critical to understand the responses of organisms to global changes. I focused on studying space use behaviors (activity patterns, micro-habitat selection) of a temperate squamate species, the common lizard (Zootoca vivipara) through experimental set-ups in laboratory or outdoor conditions, as well as a comparative study of natural populations in the Massif Central, France. My results highlighted that behavioral regulation of the water balance can trade-off or act in synergy with thermoregulation behaviors according to environmental conditions. The observed behavioral adjustments could consist in a water conservation strategy. A decrease in water availability in the environment as well as a dehydration induced changes in thermoregulation strategies (body temperature, thermoregulation accuracy). These studies highlighted the importance of a joint consideration of the thermal and water constraints when studying the ectotherms responses to global change, and questioned our current understanding of individual and populational responses to these changes