A test system was commissioned to characterize commercial thermoelectric modules to be used in the Pizza Oven Waste Energy Recovery (POWER) system for Pizza Pizza restaurants. The objective of this testing was to obtain and classify the thermoelectric material parameters of the Bi2Te3 within commercial thermoelectric generator (TEG) modules. These parameters consisted of the Seebeck coefficient, the thermal conductivity and the electrical resistivity. Together they provide the normalized figure of merit for the thermoelectric material which is a performance indicator for energy efficiency at a given operating temperature. From this research, a two phase methodology was developed that was able to extract the desired values from these modules. Material quality and device composition was first assessed with tools such as SEM and EDS. During this phase, dimensional and elemental data was gathered and a finite element model was constructed to ensure the validity of the primary selected test method for this research which was the Harman technique. The results obtained with this method were all three of the aforementioned thermoelectric parameters as well as a direct measurement of the figure of merit. Thermal and electrical losses for the TEG1B-12610-5.1 module were characterized from room temperature to 200°C using this process. It was determined that the thermal losses were more dominant and could be approximated using a function of T4 to within 1% of their calculated values. This process can be applied to any model of TEG to forecast these losses. To assist with future research, a secondary test method known as the Parallel Thermal Conductance technique was researched and a proposed model of it was designed for use in temperatures up to 300°C. Due to the relatively short test time of the Harman Technique, it was also used to effectively bin incoming groups of TEGs used in the POWER system so that they could be placed strategically in different areas of heat flow based on their measured performance. An increase of 13.2% was observed in the electrical output of the system after the binning had occurred. / Thesis / Master of Applied Science (MASc)

The goal of this project is to develop a fabrication process for an annular thermoelectric module using a powder methodology that can potentially later be automated for high volume manufacturing. Prototypes were produced and experimentally tested to study and characterize thermal and effective Seebeck performance. Manufacturing procedure parameters were changed systematically to characterize the impact on key performance parameters and develop the fabrication process. Parameters investigated were sintering temperature, pressing pressure, oxide reduction and geometry. A novel design for an annular thermoelectric generator geometry has been proposed. The new geometry utilizes more of the module material into power production making the geometry more efficient than the typical ring-structured modules similar to that proposed by Min & Rowe (2007). Experimental results tests highlighting only geometry differences showed V-shaped modules with higher effective Seebeck coefficient compared to ring-structured modules. Experimental results showed the proposed V-shaped annular thermoelectric generator prototype with a Seebeck coefficient of 190.75 µV/K compared to (Min & Rowe, 2007)’s earlier ring-structured prototype measuring a Seebeck coefficient of 145 µV/K. A numerical simulation model was created to compare electrical and thermal behaviour for different TEG module geometries. ANSYS Workbench® simulation results show that V-shaped TEG module outperforms the ring-structured design similar to Min et al.’s design by 7% to 9% under different conditions. / Thesis / Master of Science in Mechanical Engineering (MSME)

Rapporten är en utvärdering av möjligheten att generera elektrisk energi från fjärrvärme med Seebeck-effekten och görs på uppdrag av Skellefteå Kraft. Kursen är examensarbete för högskoleingenjörsexamen i Elkraftteknik, 5EL210 vid institutionen tillämpad fysik och elektronik på Umeå Universitet under vårterminen 2014.En termoelektrisk generator fungerar enligt Seebeck-effekten och genererar en elektrisk spänning som är linjär mot temperaturskillnaden mellan sina två metallytor. För att få en temperaturskillnad så krävs ett kylmedium vilket skapar ett värmeflöde från den varma energikällan till kylmediumet. Utan kylmediumet så kommer temperaturerna gå mot samma värde. Ett kylmedium kan till exempel vara snö, markgrunden eller vattenradiatorer. Eftersom en termoelektrisk generator är väldigt ineffektiv så lämpar det sig inte att använda markgrunden eller snö som kylmedium för att endast generera upp till 4% el av den tillförda värmeenergin och resten går till förluster. Av denna anledning valdes radiatorerna i villan som kylmedium för detta examensarbete.En teoretisk experimentuppställning gjordes med 16 stycken termoelektriska generatorer. Resultatet visade att värmeöverföringen genom de termoelektriska generatorerna begränsades till ca. 250W värmeenergi. Med relativt låga temperaturer så är effektiviteten endast 2% vilket genererar ca. 5W elektrisk energi.Slutsatsen är att med denna experimentuppställning så genereras inte tillräckligt med energi för att driva en cirkulationspump. Effektiviteten av de termoelektriska generatorerna är för dålig och de leder värme dåligt på grund av dess höga termiska resistans.

L'introduction d'additifs de type glycol dans les catalyseurs d'hydrotraitement afin d'avoir une meilleure activité catalytique est une procédure reconnue. Par contre, dans la littérature les avis divergent sur le mécanisme d'augmentation de l'activité. L'objectif de ce travail est donc de rationaliser le rôle des additifs par rapport (i) aux espèces présentes dans la solution d'imprégnation ainsi qu'à la surface du catalyseur et (ii) à l'étape de préparation durant laquelle se fait l'additivation. Des catalyseurs ont été préparés à partir de différentes solutions précurseurs de type CoMo(P) et de triéthylèneglycol (TEG) qui est introduit lors de différentes étapes de préparation. Une relation a été trouvé entre les espèces de surface avant l'étape de sulfuration et les activités catalytiques en hydrogénation du toluène. Plusieurs techniques d'analyse (spectroscopies Raman, UV-Visible, RMN, DRX) ont montré que le TEG joue un rôle de solvant et privilégie la formation et dispersion d'hétéropolycomposés. L'utilisation de cet additif a pour conséquence une meilleure dispersion des précurseurs de la phase active et la formation de la phase "CoMoS" est privilégiée

The purpose of this thesis has been to determine experimentally how good a peltier element is to convert waste heat from wood burning. Three different peltier elements were used in a comparison study. The comparison was mainly done to know how much power could be obtained from each element. Even, a circuit with a step-up function has been created to give a higher output voltage than the peltier element itself. The result of the experiments was a low output power, the highest value reached 2.18W. Also, the Carnot efficiency has been calculated for the three different elements and the efficiency ranged between 14 and 33%. From the circuit a constant 3.3V output was delivered. The main conclusion of this project is that furthermore Studies are needed in the material field because the elements available at the market today have too low efficiency.

La notion de taux effectif global (T.E.G.), mention informative obligatoire dans les contrats de crédit et outil de calcul des taux d’usure, est à l’origine d’importants contentieux devant les juridictions civiles. Cette recherche sur le taux effectif global porte sur le droit relatif à cette notion, les règles de sa détermination, ses fonctions juridiques et les sanctions qui sont attachées à l’inobservation de ce droit. Les prêteurs qui violent ces règles de droit sont condamnés à des restitutions d’intérêts parfois élevées. Ces condamnations incitent de nombreux emprunteurs à contrôler la mention de T.E.G. dans leur contrat de crédit et à agir en justice. Ces litiges ne sont pas tous résolus de la même manière selon les juridictions. Certaines accèdent à toutes les demandes des emprunteurs, d’autres les refusent systématiquement. Un état des lieux et une analyse des règles et des sanctions s’imposent / The concept of annual percentage rate of charge (in French, « taux effectif global »), an informative term appearing in credit agreements and a tool for calculating usury rate, is at the origin of major litigation before the civil courts. This research on the annual percentage rate of charge concerns the law relating to this concept, the rules of its determination, its legal functions and the sanctions which are attached to the non-observance of this law. Lenders who violate these rules of law are condemned to refunds of interest sometimes high. These convictions prompt many borrowers to control the mention of annual percentage rate of charge in their credit agreement and to take legal action. Not all disputes are resolved in the same way by the courts. Some access all the borrowers' requests, others systematically refuse them. An inventory of the situation and an analysis of the rules and sanctions are necessary

Coagulopathy, a condition in which blood coagulation is impaired, can be inherited or result from a variety of conditions including severe trauma, illness or surgery. Perioperative monitoring of a patient’s coagulation status is important to identify coagulopathic patients. Thromboelastography or TEG remains the gold standard for whole blood coagulation monitoring. However, TEG suffers from certain well-documented drawbacks such as contact containment and manipulation of the blood sample, large and uncontrolled strain, and the inability to distinguish the contribution of elasticity and viscosity during blood coagulation. We developed a non-contact blood rheometer which uses a single drop of blood to measure its viscoelastic properties. Small sample size (typically 5-15 μL), low shear strain (linear viscoelasticity), and non-contact manipulation and containment of samples make this technique unique for real-time monitoring of blood coagulation. In the first part of this work, we addressed the development of the technique, benchmarking the results against known material properties standards. We observed large amplitude oscillations of the levitated drop results in multiple resonance modes and excessive dissipation. We suggested upper bound limits for drop oscillation amplitudes required to satisfy the Lamb theoretical expressions for drop frequency and damping. In the second part, we applied our technique to study sickle-cell disease. Our technique showed that the shape oscillation of blood drops was able to assess an abnormally increased viscosity in sickle cell patients when compared with normal controls over a range of hematocrit. Furthermore, the technique was sensitive enough to detect viscosity changes induced by hydroxyurea treatment. The third part of this work focused on blood coagulation monitoring. The technique showed sensitivity to coagulation parameters, such as platelet count, calcium ion concentration, and hematocrit. A comparison of the results with TEG showed coagulation started sooner in the levitation technique, but with a lower rate and lower maximum stiffness. Thus, the technique developed can be used as a monitoring tool to assess blood mechanical properties sensitively enough to be of use in clinical diagnostic settings. / 2020-06-04T00:00:00Z

Background: Uncontrolled bleeding accounts for the majority of preventable deaths in the severely injured in both the civilian and military settings. Trauma induced coagulopathy (TIC) is now widely accepted as a major contributing factor to worsening bleeding in these patients. A quarter of severe trauma patients present with coagulopathy on admission and remain a group with high morbidity and mortality. Objectives: To describe the spectrum of coagulation profiles amongst severely injured patients presenting to an urban level-one trauma centre at Groote Schuur Hospital and to correlate these with blood product requirements, morbidity and mortality. Method: This is a retrospective study of all patients with complete baseline TEG coagulation parameters collected prior to randomization in the FIRST (Fluids In Resuscitation of Severe Trauma) trial between January 2007 and December 2009. Parameters recorded for this study included patient demographics, mechanism of injury, admission vital signs, lactate, base excess, coagulation studies PT, INR, TEG parameters, volume and type of fluids administered, volume of blood products administered, length of ICU stay, and major outcomes. Injury severity was categorized according to the Injury Severity Score (ISS) and New Injury Severity Score (NISS). Results: A total of 87 patients were included in this study, with a median ISS of 20 and 57.5% had a penetrating injury mechanism. Coagulopathy was highly prevalent in this cohort, of which a majority (69%) was diagnosed with hypercoagulopathy and 24% had a hypocoagulopathy status on admission. There was no difference in age, gender and amount 9 of pre-hospital fluids administered across the three groups (normal v/s hyper v/s hypo). Median volume of blood products was higher in the hypocoagulopathy group, although not statistically significant. Overall, 30-day mortality rate was 13%, with case fatalities occurring in only coagulopathic patients; hypercoagulopathy (15%) and hypocoagulopathy (10%). Conclusion: Trauma induced coagulopathy is not an infrequent diagnosis and remains a challenging clinical entity to manage in severely injured patients resulting in increased morbidity and mortality. Determining the coagulation profile using TEG at presentation in this group of patients may guide appropriate management guidelines in order to improve outcome. Hypercoagulable patients need to be recognised amongst the TIC patients as it results in different sequelae and impacts on clinical decision in the use of antifibrinolytic agents as compared to hypocoagulopathy.

Thermoelectric generator (TEG) is a solid state technology based on the Seebeck effect that can generate electrical power from waste heat. For continuous electrical power generation heat exchangers are integrated into the “cold side” and the “hot side” of the TEG such that a temperature difference across the TEG can be established and maintained. This thesis will focus on characterizing two different flat-plate cold side heat exchanger prototypes specifically designed for dissipating the thermal loads from TEG modules. The majority of TEGs modules available have a flat geometry design and a square shape with typical dimension of 40 mm × 40 mm or 56 mm × 56 mm. To maximize the net electrical power generated by the TEGs the cold side heat exchanger is required to have uniform surface temperature distribution, and excellent heat transfer performance with minimum pressure drop. To achieve the previously mentioned requirements, two flat-plate heat exchanger prototypes having two distinct heat transfer techniques were investigated. Each heat exchanger is designed to accommodate an array of 14 TEG modules arranged in two parallel rows with 7 TEGs per row a typical arrangement for large waste energy harvesting applications. The first heat exchanger prototype utilized single-phase forced convection through 140 minichannels (1 mm × 1 mm × 90 mm long) as a heat transfer technique. The second prototype utilized 14 liquid jets, 3 mm in diameter and 40.3 mm apart, impinging on a flat surface located 5 mm above. Each impinging jets was positioned at the centre of the TEG cooling area. An experimental facility was constructed in order to test the minichannels heat exchanger and the impinging jets thermally and hydrodynamically. The heat transfer, pressure drop and temperature distribution results were compared to determine the most appropriate cold side heat exchanger prototype for the TEG POWER system. The TEG POWER system is a waste heat recovery system designed to recoup waste heat from the exhaust gases of commercial pizza ovens. The TEG POWER system is capable of harvesting waste thermal energy produced by an establishment and utilize it for electrical power generation and thermal storage purposes. Heat transfer results indicated that for a given mass flow rate the minichannels heat exchanger has better heat transfer performance compared to the impinging jets heat exchanger. The minichannels heat exchanger design had a thermal conductance of 238 W/C at 0.19 kg/s coolant flow rate compared to 111 W/C for the impinging jets heat exchanger. The total pressure drop and the minor losses for each heat exchanger prototype were measured experimentally. For the minichannels heat exchanger, the total pressure drop is 23.3 kPa at flow rate of 0.235 kg/s. Comparatively, the total pressure drop for the impinging jets heat exchanger was 27.4 kPa at the same flow rate. Fittings losses for the minichannels heat and impinging jets heat exchanger were found to be 50% and 80% respectively. The maximum total measured drop corresponded to pumping power requirements of 5.7 W and 6.8 W for the minichannels and impinging jets heat exchanger respectively. Local and average temperature distributions and their influence on the electrical power generated were studied for both heat exchanger prototypes. It was found that the minichannels heat exchanger offers more uniform surface temperature distribution per row of TEGs compared to the impinging jets heat exchanger. Therefore the minichannels heat exchanger is well suited for cooling two rows of TEGs simultaneously. Based on the thermal and hydrodynamics comparison results the minichannels heat exchanger prototype is recommended for implementation in the TEG POWER system. / Thesis / Master of Applied Science (MASc)

No description available.