Academic literature on the topic 'Heat'

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Journal articles on the topic "Heat"

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Dukenik, David Bared, Deborah Soong, Frank Scarpa, Julia Anderson, Hua Li, Viji Udayakuma, Justin M. Watts, et al. "Distinct SF3B1 Allele HEAT Repeat Location Is Associated with Co-Occurring Mutation Patterns in MDS." Blood 142, Supplement 1 (November 28, 2023): 3242. http://dx.doi.org/10.1182/blood-2023-181191.

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Background: In 2022, the WHO classified a new subtype of myelodysplastic neoplasms (MDS) with low blast count and SF3B1 mutation called MDS- SF3B1. SF3B1 is the major subunit of the SF3B spliceosome complex and is responsible for recognizing 3' splice sites in pre-mRNA for processing into mature mRNA. Mutations in SF3B1 have also been observed in other myeloid neoplasms. While MDS- SF3B1 has been associated with a better survival outcome, allelic variants such as SF3B1 K666N are associated with higher-risk MDS, transformation to AML and decreased OS. Additionally, SF3B1 E592K is more likely to be co-mutated with RUNX1, with a worse prognosis. Thus, not all SF3B1 allelic variants should be treated the same. The IPSS-M model incorporates SF3B1 mutations with different weights depending on co-mutations (i.e. isolated del(5q) or BCOR, BCORL1, RUNX1, NRAS, STAG2, SRSF2 mutations) but did not find a difference based on SF3B1 hotspot mutation. However, these and other studies have focused on specific amino acid substitutions but have not taken into consideration the protein domain structure of SF3B1. Using a large cohort of SF3B1-mutant myeloid malignancies, we determined whether HEAT repeat domain location was associated with differences between SF3B1-mutant myeloid neoplasms when comparing co-mutations and clinical characteristics. Methods: Bone marrow, peripheral blood, or FFPE tissue samples from a cohort of 2,996 unique patients with a suspected myeloid neoplasm from 6/30/2020-5/30/2023 were sequenced using a DNA 297 gene myeloid panel. We also analyzed a separate cohort of 112 patients from Sylvester Comprehensive Cancer Center (SCCC) and the University of Texas Southwestern Medical Center (UTSW) from 06/01/2017-06/30/2023 to validate the findings and assess for associations with clinical parameters such as blast count, time to disease progression, and survival. Statistics were performed using Chi-Square. SF3B1 has 22 HEAT repeats with SF3B1 mutations occurring predominately in HEAT Domains 2-6. For this study, we used UniProt definitions of amino acids 569-603 (HEAT2), 604-641 (HEAT3), 643-677 (HEAT4), 680-718 (HEAT5), and 763-801 (HEAT6) as shown in Figure 1. Results: Out of 2,996 myeloid neoplasm patients with SF3B1 mutations, the SF3B1 allele with the highest prevalence was K700E, which falls into HEAT repeat number 5, followed by K666N/R/T and H662Q in HEAT repeat number 4, and R635C in HEAT repeat number 3. Mutations in HEAT repeat 2 and 6 were less common. Several genes were significantly co-mutated in different SF3B1 heat domains, including ASXL1 (11%, p-value =<0.00001), CUX1 (4.7%, p-value = <0.00001), DNMT3A (22.5%, p-value = <0.00001), EZH2 (4.3%, p-value = 0.07), JAK2 (11.2%, p-value= <0.00001), RUNX1 (7.8%, p-value = <0.00001), STAG2 (3.2%, p-value = <0.00001), and TET2 (28.2%, p-value = 0.003) shown in Table 1. The most common co-mutations within each HEAT domain were: HEAT2- ASXL1 (80.0%), RUNX1 (55%), and STAG2 (25%); HEAT3- TET2 (29.5%), DNMT3A (17.5%), and ASXL1 (12.6%); HEAT4- TET2 (24%), D NMT3A (15.2%), and JAK2 (16.9%); HEAT5- TET2 (31.4%) and DNMT3A (31%);and HEAT6- TET2 (28.9%), ASXL1 (15.8%), DMNT3A (14.5%), and EZH2(10.5%). In a separate cohort of 112 patients with clinical follow-up, 97 were diagnosed with MDS- SF3B1: 53 (55%) were male and the average age at diagnosis of 70 years (range: 27-89 years old). A total of 88 patients had 297 gene myeloid panel information, which revealed a similar HEAT repeat distribution: HEAT3 (19%), HEAT4 (27%), HEAT5 (45%), and HEAT6 (6%). The median OS of the entire cohort was 10.5 years (CI 95% 4.93-NE). With a median follow-up of 2 years; 75, 81, 63 and 80% of patients were alive in HEAT 3, 4, 5 and 6, respectively. Conclusion: Distinct SF3B1 alleles defined by HEAT repeat location reflect distinct co-mutation patterns and may play a role in the biology of myeloid disorders. The relatively most enriched co-mutation patterns included: ASXL1 and RUNX1 in HEAT2, JAK2 in HEAT4, and EZH2 in HEAT6. Despite numerical differences in survival larger multicenter patient cohorts are needed to further define how distinct SF3B1 allelic variants and their HEAT repeat location correlate with prognosis and outcome in MDS and other myeloid neoplasms. In addition, further research is need into whether distinct SF3B1 alleles result in differences in RNA splicing signatures that may influence interactions with co-occurring mutations and disease biology.
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Gurney, Shae C., Katherine S. Christison, Tyler Stenersen, and Charles L. Dumke. "Effect of uncompensable heat from the wildland firefighter helmet." International Journal of Wildland Fire 30, no. 12 (2021): 990. http://dx.doi.org/10.1071/wf20181.

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Heat accumulation from wearing personal protective equipment can result in the development of heat-related illnesses. This study aimed to investigate factors of heat stress with and without a US standard issue wildland firefighter helmet. Ten male subjects finished a 90-min exercise protocol in a heat chamber (35°C and 30% relative humidity), with standard issue meta-aramid shirt and pants and a cotton t-shirt, and either with or without a wildland firefighter helmet. A randomised crossover design was implemented, with a minimum 2-week washout period. Heart rate, physiologic strain index, perceived head heat, head heat and skin blood flow of the head and neck were measured. At the conclusion of the 90-min trial, heart rate, physiological strain index, core temperature, rating of perceived exertion and perceived head heat showed a main effect of time (P < 0.05). Perceived head heat and head heat exhibited a main effect of trial (P < 0.05). The change in physiologic strain was positively correlated with the change in skin blood flow of the head (r = 0.72, P = 0.02). These data suggest that the current wildland firefighter helmet contributes to heat accumulation. The design of the wildland firefighter helmet lacks ventilation, which, from these data, may result in metabolic alterations and perceived discomfort.
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Choi, Byung-Hui, and Chang-Oh Kim. "A Study on the Numerical Analysis of Heat Sink for Radiant Heat of Automotive LED Head Lamp." Journal of the Korea Academia-Industrial cooperation Society 13, no. 10 (October 31, 2012): 4398–404. http://dx.doi.org/10.5762/kais.2012.13.10.4398.

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van der Laarse, Willem J. "Heart heat separation." Journal of Physiology 595, no. 14 (June 16, 2017): 4579–80. http://dx.doi.org/10.1113/jp274564.

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Tojiboyev, Boburjon, and Maftuna Mullajonova. "REASONABLE USE OF HEAT AND HEAT CONDUCTIVITY PROPERTIES OF HEAT PRESERVING COATINGS." International Journal of Advance Scientific Research 4, no. 3 (March 1, 2024): 96–101. http://dx.doi.org/10.37547/ijasr-04-03-19.

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In addition to discussing the current techniques for figuring out the thermal conductivity of these heat-insulating coatings, the piece also details the outcomes of experimental research on the analysis and advancement of energy-saving materials and their application to recently built modern buildings and structures.
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Ahmad, Mateen, Waseem Saeed, and Khaqan Javed. "Temperature Distribution Analysis along the Length of Floating Head Multi Stream Heat Exchanger." International Journal of Chemical Engineering and Applications 12, no. 3 (September 2021): 17–21. http://dx.doi.org/10.18178/ijcea.2021.12.3.790.

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Heat transfer between two streams is common and simple and well established and perfectly commercialized. Normally, the exchanger that is used for this purpose is shell and tube heat exchanger but in some industrial production unit where more than one reactant is to be preheated or pre-cooled for chemical reaction and same as post heating and post cooling required of multiple streams at same or different temperatures, Problem that is associated with such type shell and tube heat exchanger is that it can’t handle the multiple stream and for handling multiple streams we required more number of exchangers due to which capital cost increases and required more care of handling because the number of units increases. To overcome this problem, we need more than one heat sinks with one or more than one heat source that will minimize the covered volume per unit heat transfer area, the number of unit operation, operation time, man power and the capital cost with increasing thermal efficiency and heat utilization so to overcome this problem we need to move towards multi stream heat exchanger for handling multiple streams at once for heat exchange. Multi stream heat exchanger is opening of a new class of heat transfer equipment which deals more than two different streams for heat exchange. Such a way number of units can be reduced, which minimize time and space. With a little bit increase in complexity the operational cost will decrease and improve the thermal efficiency of heat transfer equipment, which minimize thermal losses and maximize the heat utilization which directly decrease the equipment size and capital cost. In the previous study we have discuss our research on the fabrication and Comparative Study of Floating Head (Triple pipe) Multi Stream Heat Exchanger with Shell & Tube This work is about the investigation involves the tentative examination of the heat exchange through the Floating Head Multi-Stream Heat Exchanger to evaluate the temperature distribution along the length, in which cool liquids are flowing through the inner and external pipe and hot liquid is moving through the central pipe of the exchanger.
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Voelker, R. "Heat and Heart Attack." JAMA: The Journal of the American Medical Association 281, no. 18 (May 12, 1999): 1689—c—1689. http://dx.doi.org/10.1001/jama.281.18.1689-c.

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Voelker, Rebecca. "Heat and Heart Attack." JAMA 281, no. 18 (May 12, 1999): 1689. http://dx.doi.org/10.1001/jama.281.18.1689-jwm90003-4-1.

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Desai, Yash, Haitham Khraishah, and Barrak Alahmad. "Heat and the Heart." Yale Journal of Biology and Medicine 96, no. 2 (June 30, 2023): 197–203. http://dx.doi.org/10.59249/hgal4894.

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Nelson, Michael D., Luis A. Altamirano-Diaz, Stewart R. Petersen, Darren S. DeLorey, Michael K. Stickland, Richard B. Thompson, and Mark J. Haykowsky. "Left ventricular systolic and diastolic function during tilt-table positioning and passive heat stress in humans." American Journal of Physiology-Heart and Circulatory Physiology 301, no. 2 (August 2011): H599—H608. http://dx.doi.org/10.1152/ajpheart.00127.2011.

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The ventricular response to passive heat stress has predominantly been studied in the supine position. It is presently unclear how acute changes in venous return influence ventricular function during heat stress. To address this question, left ventricular (LV) systolic and diastolic function were studied in 17 healthy men (24.3 ± 4.0 yr; mean ± SD), using two-dimensional transthoracic echocardiography with Doppler ultrasound, during tilt-table positioning (supine, 30° head-up tilt, and 30° head-down tilt), under normothermic and passive heat stress (core temperature 0.8 ± 0.1°C above baseline) conditions. The supine heat stress LV volumetric and functional response was consistent with previous reports. Combining head-up tilt with heat stress reduced end-diastolic (25.2 ± 4.1%) and end-systolic (65.4 ± 10.5%) volume from baseline, whereas heart rate (37.7 ± 2.0%), ejection fraction (9.4 ± 2.4%), and LV elastance (37.7 ± 3.6%) increased, and stroke volume (−28.6 ± 9.4%) and early diastolic inflow (−17.5 ± 6.5%) and annular tissue (−35.6 ± 7.0%) velocities were reduced. Combining head-down tilt with heat stress restored end-diastolic volume, whereas LV elastance (16.8 ± 3.2%), ejection fraction (7.2 ± 2.1%), and systolic annular tissue velocities (22.4 ± 5.0%) remained elevated above baseline, and end-systolic volume was reduced (−15.3 ± 3.9%). Stroke volume and the early and late diastolic inflow and annular tissue velocities were unchanged from baseline. This investigation extends previous work by demonstrating increased LV systolic function with heat stress, under varied levels of venous return, and highlights the preload dependency of early diastolic function during passive heat stress.
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Dissertations / Theses on the topic "Heat"

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Dellorusso, Paul Robert. "Electrohydrodynamic heat transfer enhancement for a latent heat storage heat exchanger." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1998. http://www.collectionscanada.ca/obj/s4/f2/dsk2/tape17/PQDD_0027/MQ31562.pdf.

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Solder, Jeffery. "Heat." Digital Commons at Loyola Marymount University and Loyola Law School, 1986. https://digitalcommons.lmu.edu/etd/853.

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Forinash, David Michael. "Novel air-coupled heat exchangers for waste heat-driven absorption heat pumps." Thesis, Georgia Institute of Technology, 2015. http://hdl.handle.net/1853/53897.

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A detailed investigation of novel air-coupled absorbers for use in a diesel engine exhaust-driven ammonia-water absorption system operating in extreme ambient conditions was conducted. Electrically driven vapor-compression systems are under scrutiny due to the environmental impact of synthetic refrigerants and the exacerbation of electric utility loads during peak demand periods. One alternative to vapor-compression systems is the absorption heat pump that uses environmentally benign working fluids and can be driven by a variety of heat sources, including waste heat and solar thermal processes. Direct air coupling of the absorber and condenser instead of indirect hydronic coupling can reduce absorption system size, complexity, and inefficiency, but materials compatibility issues with ammonia-water and the poor heat transfer properties of air present challenges. Heat and mass transfer modeling was used to predict the performance of round-tube corrugated-fin and compact tube-array absorbers designed for a 2.64-kW absorption chiller operated in high ambient temperature (51.7°C) conditions. A single-pressure ammonia-water test facility was constructed and used in conjunction with a temperature- and humidity-controlled air-handling unit to evaluate the absorbers at design and off-design operating conditions. Absorber performance was recorded over a range of air temperatures (35-54.4°C), air flow rates (0.38-0.74 m3 s-1), inlet solution temperatures (92-102°C), concentrated solution flow rates (0.006-0.010 kg s-1), and concentrated solution concentrations (38-46%). At design conditions, round-tube corrugated-fin absorbers of 394 and 551 Fins Per Meter (FPM) demonstrated comparable performance (Q394-FPM,exp = 4.521±0.271 kW; Q551-FPM,exp = 4.680±0.260 kW), and measured heat transfer rates were 0.7-1.9% AAD higher than those predicted through modeling. The measured heat transfer rate in the prototype tube-array absorber was significantly lower than the values predicted at design conditions (Qprot,exp = 2.22±0.24 kW; Qprot,mod = 4.33 kW). Maldistribution of the two-phase flow in the tube array is the probable cause of the disparity between the prototype absorber data and model predictions. Results from this investigation can be used to guide the development of air-coupled heat and mass exchangers for compact absorption heat pumps.
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Grundén, Emma, and Max Grischek. "Testing the Heat Transfer of a Drain Water Heat Recovery Heat Exchanger." Thesis, KTH, Energiteknik, 2016. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-190188.

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This study investigates the change in thermal resistance due to fouling in drain water pipes. As insulation of houses and energy efficiency of appliances improve, the importance of Drain Water Heat Recovery (DWHR) is growing steadily. In older houses, the relative heat loss through drain water is smaller than in newly built houses, but should still be considered. For example, 17 % of the total heat loss in Swedish multi-family houses built before 1940 was transported with the drain water (Ekelin et al., 2006). The average temperature of drain blackwater is between 23 °C and 26 °C (Seybold & Brunk, 2013), and a part of its heat can be recovered in DWHR systems. This allows cold incoming water to houses and buildings to be pre-heated by drain water before it is heated in the heat pump. Depending on the system, 30 % to 75 % of the heat from drain water can be recovered (Zaloum et al., 2007b). A threat to heat exchanger performance is that additional materials, so called fouling, accumulate on the surfaces of the heat exchangers and increases its thermal resistance. This resistance can be described by a fouling resistance and can be very costly due to losses in heat transfer and required cleaning. To quantify the fouling resistance, experiments were conducted in a climate chamber on Brinellvägen 66, using a pipe that had been installed for 3 years in the sewage system from the men’s toilet on Brinellvägen 64B. The installed pipe was compared with a pipe from the same manufacturer with the same dimensions. The pipes were sealed and filled with water at about 20 °C. Thermocouples were used to measure the decrease in water temperature over time in both pipes. Based on these measurements, the difference in thermal resistance was found, using curve fitting and the Lumped Capacitance Method. The fouling resistance was quantified by comparing the thermal resistances of the test pipe with and without fouling. The main findings were firstly that fouling significantly increases the thermal resistance of aluminium pipes. Secondly, corrosion causes a significant decrease in the pipes’ thermal resistance. The combination of these effects led to a decrease of 14 % in thermal resistance in the examined system after three years compared to the time of installation. The decrease in thermal resistance due to corrosion in the test pipe was 44 % compared to the time of installation. Furthermore, the thermal resistance of the test pipe decreased by 51 % when it was cleaned from the fouling. The fouling resistance of the 0.81 mm fouling layer was found to be 0.03068 m2K/W.
Denna studie undersöker den ökade termiska resistansen i avloppsrör på grund av beläggningar. Idag lägg stor vikt vid bra isolering och energieffektiv utrustning i nybyggda hus, vilket även sätter press på värmeåtervinning av avloppsvatten. Värmeåtervinningen av avloppsvatten är mindre viktig i äldre hus, då den relativa värmeförlusten av avloppsvatten är lägre än i nybyggda hus, men bör likväl tas i akt vid utvärderingen av värmeanvändning. I ett svenskt flerfamiljshus byggt före 1940 stod värmeförlusten på grund av varmt avloppsvatten för 17 % av den totala värmeförlusten (Ekelin et al., 2006). Den genomsnittliga temperaturen för svartvatten ligger på 23 °C till 26 °C (Seybold & Brunk, 2013), varav delar av värmen kan återvinnas i värmeväxlare. Detta bidrar till att det kalla ingående vattnet till värmepumpen förvärms av värmen från avloppsvattnet. Beroende på system och material kan 30 % till 75 % av värmen från avloppsvatten återvinnas (Zaloum et al., 2007b). Ett hot mot prestandan av värmeväxlare är att beläggning formas på de värmeöverförande ytorna i värmeväxlaren. Detta bidrar till en ökad termisk resistans och kan vara mycket kostsam på grund av minskning av värmeöverföring och nödvändig rengöring av anordningen. För att undersöka omfattningen av den ökade termiska resistansen utfördes en rad experiment i en klimatkammare på Brinellvägen 66. En jämförande metod användes där ett aluminiumrör, som tidigare installerats i avloppssystemet från herrarnas toalett i korridoren på Brinellvägen 64B, jämfördes med ett identiskt rör av samma tillverkare. Rören var tätade och fyllda med 20-gradigt kranvatten. Termoelement användes för att, över tid, mäta minskningen av vattentemperaturen i rören. Temperaturskillnaden användes för att beskriva skillnaden i termisk resistans genom att utföra kurvanpassning och tillämpa Lumped Capacitance Method. Skillnaden i termisk resistans mellan de båda rören antogs vara lika med beläggningens motstånd för värmeöverföring. Två huvudsakliga resultat kom av studien. Det första var att beläggning bidrar till ökad termisk resistans av aluminiumrör. Den andra var att korrosion tillsammans med andra externa faktorer orsakar en märkbar minskning av rörens termiska resistans. Totalt sett orsakade beläggningen tillsammans med korrosion en minskning av 14 % av den termiska resistansen i provröret, jämfört med den termiska resistansen vid installationstillfället. Vidare låg minskningen i termisk resistans på grund av korrosion i teströret på 44 % jämfört med den termiska resistansen vid installationstillfället och den genomsnittliga termiska resistansen av det rengjorda teströret låg på 51 % lägre än den genomsnittliga resistansen av teströret innan rengöring. Den beräknade resistansen för ett 0.81 mm tjockt lager av beläggning var 0.03068 m2K/W.
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Razavinia, Nasimalsadat. "Waste heat recovery with heat pipe technology." Thesis, McGill University, 2010. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=94983.

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High grade energy, which is primarily derived from hydrocarbon fuels, is in short supply; therefore alternative energy sources such as renewable and recycled energy sources are gaining significant attention. Pyro-metallurgical processes are large consumers of energy. They in return generate large quantities of waste heat which goes un-recovered. The overall theme of this research is to capture, concentrate and convert some of this waste heat to a valuable form. The main objective is to characterize and develop heat pipe technology (some of which originated at McGill) to capture and concentrate low grade heat. Heat pipe employs boiling as the means to concentrate the energy contained in the waste heat and transfers it as higher quality energy. The distinct design features of this device (separate return line and flow modifiers in the evaporator) maximize its heat extraction capacity. During the testing the main limitations within the heat pipe were identified. Different test phases were designed throughout which the configuration of the system was modified to overcome these limitations and to increase the amount of extracted heat.
L'énergie d'haut grade de nos jours est produite principalement à base de combustion d'hydrocarbure et les réserves de cette énergie deviennent de plus en plus rare, mais certaines énergies alternatives connues gagnent des forces parmi les marchés incluant les sources d'énergie renouvelables et recyclées. Les usines pyrométallurgiques sont des consommateurs significatifs d'énergie d'haut grade. Ces procédés industriels relâches un montant important de chaleurs (perte) à l'environnement sans aucune récupération. Le but du projet est de concentrer, capturer et convertir cette chaleur résiduelle de basse qualité en énergie valable. Par contre, l'objectif principal du projet comme tel est de développer et de perfectionner un caloduc capable d'extraire cette chaleur parvenant des gaz effluents. Le point d'ébullition d'une substance (vapeur) est utilisé comme moyen de concentrer l'énergie contenu dans les effluents avec la technologie des caloducs. Pour maximiser les gains énergétiques, la conception de ce caloduc en particulier utilise des canaux de retour indépendant ainsi qu'un modificateur de débit dans l'évaporateur, lui permettant d'extraire un niveau supérieur de chaleur. Pendant les essais lors du projet, les éléments limitants des systèmes de caloducs ont été identifiés. Les configurations du système ont été ajustées et modifiés dans la phase expérimentale d'essai pour surmonter ces limitations et maximiser l'extraction de chaleur.
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Webber, Helen. "Compact heat exchanger heat transfer coefficient enhancement." Thesis, University of Bristol, 2011. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.540881.

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Riegler, Robert L. "Heat transfer optimization of grooved heat pipes /." free to MU campus, to others for purchase, 2004. http://wwwlib.umi.com/cr/mo/fullcit?p1422959.

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Da, Riva Enrico. "Two-phase Heat Transfer in Minichannel Heat Exchangers: Heat Pump Applications, Design, Modelling." Doctoral thesis, Università degli studi di Padova, 2009. http://hdl.handle.net/11577/3426130.

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Refrigerant charge minimization is one of the most important targets for heating and air conditioning applications when using natural refrigerants like hydrocarbons or ammonia to cope with the new environmental challenges. Some applications of minichannels for charge minimization in heat pumps are presented and discussed in this thesis. The design of an innovative condenser, an evaporator and an internal heat exchanger is presented. These devices are shell-and-tube heat exchangers using 2 mm i.d. minichannels and realized for the use with propane. Computational procedures based on empirical correlations available in the literature and a simplified model of the heat transfer and pressure drop processes have been developed and used for the design. Experimental performance data of the heat exchangers when using R22 and propane is reported and compared against the predictions given by the computational procedures. The shell-and-tube minichannel heat exchangers have been installed in a 100 kW heat pump using propane as the refrigerant. The unit has been designed for laboratory tests and the minichannel shell-and-tube heat exchangers have been installed in the facility together with a conventional plate condenser and an evaporator. Different configurations have been tested in order to quantify the advantages of operating the heat pump using the low charge heat exchangers, with regard to both energy performance and propane charge. In particular, the experimental performance when using the minichannel condenser is compared to the one obtained when using the plate condenser, and the influence of the internal heat exchanger on the performance of the equipment is measured and discussed. Experimental data about the efficiency with propane of the semihermetic compressor installed in the heat pump is also reported. Besides empirical correlations to predict the global thermal performance, a more complete understanding of the two-phase flow and heat transfer in minichannels is needed for the design and optimization of heat exchangers. Some CFD simulations are presented in this thesis using the innovative Volume Of Fluid (VOF) method, which is able to directly compute multiphase flows without using any empirical closure law to model the interaction between the phases. In order to assess the capability of the method to compute the motion of the gas-liquid interface, which is crucial for two-phase flow and heat transfer, simulations of the adiabatic churn flow regime of air-water mixture at different pipe diameters and liquid and gas superficial velocities have been initially performed. A comparison of the numerical results with experimental visualizations is reported and a simplified theoretical model of the wave levitation process has been developed and used to explain the numerical results. The VOF simulations were then extended to the study of condensation of R134a inside a minichannel with 1 mm internal diameter. Computational results about the evolution of the vapour-liquid interface and the heat transfer coefficient along the channel are reported.
La riduzione della carica di refrigerante nelle applicazioni di condizionamento e riscaldamento è uno dei vincoli di progetto principali quando vengono utilizzati, per motivi di carattere ambientale, refrigeranti naturali come idrocarburi ed ammoniaca. Alcune applicazioni dei minicanali per la minimizzazione della carica nelle pompe di calore vengono presentate e discusse nella presente tesi. Viene presentato il progetto di un condensatore, un evaporatore ed uno scambiatore di calore rigenerativo innovativi. Questi componenti sono degli scambiatori di calore a fascio tubiero utilizzanti minicali del diametro di 2 mm e progettati per l’uso con propano. Delle procedure di calcolo basate su di correlazioni disponibili in letteratura ed un modello semplificato del processo di scambio termico sono state utilizzate per il progetto. Le prestazioni sperimentali degli scambiatori con R22 e propano vengono riportate e confrontate con le stime fornite dalle procedure di calcolo. Gli scambiatori di calore sono stati installati in una pompa di calore della capacità termica di 100 kW utilizzante propano come fluido frigorigeno. Nell’impianto della pompa di calore, destinata a test di laboratorio, sono stati installati anche un condensatore ed un evaporatore a piastre convenzionali. In questo modo è stato possibile confrontare diverse configurazioni al fine di quantificare in via sperimentale i vantaggi apportati dall’utilizzo degli scambiatori a minicanali, in termini sia di prestazioni energetiche, sia di carica di propano richiesta. In particolare, le prestazioni delle configurazioni utilizzanti il condensatore a minicanali vengono confrontate con quelle delle configurazioni utilizzanti lo scambiatore a piastre, e l’influenza sulle prestazioni energetiche dello scambiatore rigenerativo viene misurata e discussa. Vengono inoltre riportati dati sperimentali relativi all’efficienza con propano del compressore semiermetico installato nella pompa di calore. Oltre a correlazioni empiriche in grado di stimare le prestazioni termiche globali, il progetto e l’ottimizzazione di scambiatori di calore richiede una più approfondita conoscenza del deflusso e dello scambio termico all’interno di minicanali. Vengono presentate in questa tesi delle simulazioni di termofluidodinamica computazionale tramite l’innovativo metodo VOF (Volume Of Fluid) in grado di simulare direttamente deflussi multifase senza la necessità di utilizzare correlazioni empiriche per la modellazione dell’interazione tra le fasi. Al fine di validare l’efficacia di questo metodo nel calcolare il moto dell’interfaccia gas-liquido, il quale è un aspetto cruciale nello scambio termico bifase, sono state in un primo momento eseguite delle simulazioni del regime di deflusso ”churn flow” per una miscela aria-acqua nel caso di un tubo liscio verticale adiabatico, a differenti valori di diametro del tubo e di velocità superficiale delle due fasi. I risultati sono stati confrontati con visualizzazioni sperimentali ed un modello teorico semplificato del processo di levitazione delle onde è stato sviluppato ed utilizzato per commentare i risultati numerici. Le simulazioni con il metodo VOF sono state in un secondo momento estese allo studio della condensazione di R134a all’interno di un minicanale del diametro di 1 mm. Vengono riportati risultati computazionali relativi all’evoluzione dell’interfaccia vapore-liquido e dei coefficienti di scambio termico lungo il minicanale.
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9

Meyer, Meyer. "Development of a range of air-to-air heat pipe heat recovery heat exchangers." Thesis, Stellenbosch : University of Stellenbosch, 2004. http://hdl.handle.net/10019.1/16389.

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Thesis (MScIng)--University of Stellenbosch, 2004.
ENGLISH ABSTRACT: As the demand for less expensive energy is increasing world-wide, energy conservation is becoming a more-and-more important economic consideration. In light of this, means to recover energy from waste fluid streams is also becoming more-and-more important. An efficient and cost effective means of conserving energy is to recover heat from a low temperature waste fluid stream and use this heat to preheat another process stream. Heat pipe heat exchangers (HPHEs) are devices capable of cost effectively salvaging wasted energy in this way. HPHEs are liquid-coupled indirect transfer type heat exchangers except that the HPHE employs heat pipes or thermosyphons as the major heat transfer mechanism from the high temperature to the low-temperature fluid. The primary advantage of using a HPHE is that it does not require an external pump to circulate the coupling fluid. The hot and cold streams can also be completely isolated preventing cross-contamination of the fluids. In addition, the HPHE has no moving parts. In this thesis, the development of a range of air-to-air HPHEs is investigated. Such an investigation involved the theoretical modelling of HPHEs such that a demonstration unit could be designed, installed in a practical industrial application and then evaluated by considering various financial aspects such as initial costs, running costs and energy savings. To develop the HPHE theoretical model, inside heat transfer coefficients for the evaporator and condenser sections of thermosyphons were investigated with R134a and Butane as two separate working fluids. The experiments on the thermosyphons were undertaken at vertical and at an inclination angle of 45° to the horizontal. Different diameters were considered and evaporator to condenser length ratios kept constant. The results showed that R134a provided for larger heat transfer rates than the Butane operated thermosyphons for similar temperature differences despite the fact that the latent heat of vaporization for Butane is higher than that of R134a. As an example, a R134a charged thermosyphon yielded heat transfer rates in the region of 1160 W whilst the same thermosyphon charged with Butane yielded heat transfer rates in the region of 730 W at 23 °C . Results also showed that higher heat transfer rates were possible when the thermosyphons operated at 45°. Typically, for a thermosyphon with a diameter of 31.9 mm and an evaporator to condenser length ratio of 0.24, an increase in the heat transfer rate of 24 % could be achieved. Theoretical inside heat transfer coefficients were also formulated which were found to correlate reasonably well with most proposed correlations. However, an understanding of the detailed two-phase flow and heat transfer behaviour of the working fluid inside thermosyphons is difficult to model. Correlations proposing this behaviour were formulated and include the use of R134a and Butane as the working fluids. The correlations were formulated from thermosyphons of diameters of 14.99 mm, 17.272 mm, 22.225 mm and 31.9 mm. The evaporator to condenser length ratio for the 31.9 mm diameter thermosyphon was 0.24 whilst the other thermosyphons had ratios of 1. The heat fluxes ranged from 1800-43500 W/m2. The following theoretical inside heat transfer coefficients were proposed for vertical and inclined operations (READ CORRECT FORMULA IN FULL TEXT ABSTRACT) φ = 90° ei h = 3.4516x105Ja−0.855Ku1.344 φ = 45° ei h = 1.4796x105Ja−0.993Ku1.3 φ = 90° l l l ci l l v h x k g 1/ 3 2.05 2 4.61561 109Re 0.364 ν ρ ρ ρ − ⎡ ⎡ ⎛ ⎞⎤ ⎤ = ⎢ ⎢ ⎜ ⎟⎥ ⎥ ⎢ ⎢ ⎜ − ⎟⎥ ⎥ ⎣ ⎣ ⎝ ⎠⎦ ⎦ φ = 45° l l l ci l l v h x k g 1/ 3 1.916 2 3.7233 10 5Re 0.136 ν ρ ρ ρ − ⎡ ⎡ ⎛ ⎞⎤ ⎤ = ⎢ ⎢ ⎜ ⎟⎥ ⎥ ⎢ ⎢ ⎜ − ⎟⎥ ⎥ ⎣ ⎣ ⎝ ⎠⎦ ⎦ The theoretically modelled demonstration HPHE was installed into an existing air drier system. Heat recoveries of approximately 8.8 kW could be recovered for the hot waste stream with a hot air mass flow rate of 0.55 kg/s at an inlet temperature of 51.64 °C and outlet temperature of 35.9 °C in an environment of 20 °C. Based on this recovery, energy savings of 32.18 % could be achieved and a payback period for the HPHE was calculated in the region of 3.3 years. It is recommended that not withstanding the accuracies of roughly 25 % achieved by the theoretically predicted correlations to that of the experimental work, performance parameters such as the liquid fill charge ratios, the evaporator to condenser length ratios and the orientation angles should be further investigated.
AFRIKAANSE OPSOMMING: As gevolg van die groeiende aanvraag na goedkoper energie, word die behoud van energie ‘n al hoe belangriker ekonomiese oorweging. Dus word die maniere om energie te herwin van afval-vloeierstrome al hoe meer intensief ondersoek. Een effektiewe manier om energie te herwin, is om die lae-temperatuur-afval-vloeierstroom (wat sou verlore gaan) se hitte te gebruik om ‘n ander vloeierstroom mee te verhit. Hier dien dit dan as voorverhitting van die ander, kouer, vloeierstroom. Hittepyp hitteruilers (HPHR’s) is laekoste toestelle wat gebruik kan word vir hierdie doel. ‘n HPHR is ‘n vloeistof-gekoppelde indirekte-oordrag hitteruiler, behalwe vir die feit dat dié hitteruiler gebruik maak van hittepype (of hittebuise) wat die grootste deel van sy hitteoordragsmeganisme uitmaak. Die primêre voordele van ‘n HPHR is dat dit geen bewegende dele het nie, die koue- en warmstrome totaal geïsoleer bly van mekaar en geen eksterne pomp benodig word om die werkvloeier mee te sirkuleer nie. In hierdie tesis word ‘n ondersoek gedoen oor die ontwikkeling van ‘n bestek van lug-totlug HPHR’s. Hierdie ondersoek het die teoretiese modellering van so ‘n HPHR geverg, sodat ‘n demonstrasie eenheid ontwerp kon word. Hierdie demonstrasie eenheid is geïnstalleer in ‘n praktiese industriële toepassing waar dit geïvalueer is deur na aspekte soos finansiële voordele en energie-besparings te kyk. Om die teoretiese HPHR model te kon ontwikkel, moes daar gekyk word na die binnehitteoordragskoëffisiënte van die verdamper- en kondensordeursneë, asook R134a en Butaan as onderskeie werksvloeiers. Die eksperimente met die hittebuise is gedoen in die vertikale en 45° (gemeet vanaf die horisontaal) posisies. Verskillende diameters is ook ondersoek, maar met die verdamper- en kondensor-lengteverhouding wat konstant gehou is. Die resultate wys dat R134a as werksvloeier in die hittebuise voorsiening maak vir groter hitteoordragstempo’s in vergelyking met Butaan as werksvloeier by min of meer dieselfde temperatuur verskil – dít ten spyte van die feit dat Butaan ‘n hoër latente-hittetydens- verdampings eienskap het. As voorbeeld gee ‘n R134a-gelaaide hittebuis ‘n hitteoordragstempo van omtrent 1160 W terwyl dieselfde hittebuis wat met Butaan gelaai is, slegs ongeveer 730 W lewer by 23 °C. Die resultate wys ook duidelik dat hoër hitteoordragstempo’s verkry word indien die hittebuis bedryf word teen ‘n hoek van 45°. ‘n Tipiese toename in hitteoordragstempo is ongeveer 24 % vir ‘n hittebuis met ‘n diameter van 31.9 mm en ‘n verdamper- tot kondensor-lengteverhouding van 0.24. Teoretiese binne-hitteoordragskoëffisiënte is ook geformuleer. Dié waardes stem redelik goed ooreen met die meeste voorgestelde korrelasies. Nieteenstaande die feit dat gedetailleerde twee-fase-vloei en die hitteoordragsgedrag van die werksvloeier binne hittebuise nog nie goed deur die wetenskaplike wêreld verstaan word nie. Korrelasies wat hierdie gedrag voorstel is geformuleer en sluit weereens die gebruik van R134a en Butaan as werksvloeiers in. Die korrelasies is geformuleer vanaf hittebuise met diameters van onderskeidelik 14.99 mm, 17.272 mm, 22.225 mm en 31.9 mm. Die verdamper- tot kondensor-lengteverhoudings vir die 31.9 mm deursnit hittebuis was 0.24 terwyl die ander hittebuise ‘n verhouding van 1 gehad het. Die hitte-vloede het gewissel van 1800-45300 W/m2. Die volgende teoretiese geformuleerde binne-hitteoordragskoëffisiënte word voorgestel vir beide vertikale sowel as nie-vertikale toepassing (LEES KORREKTE FORMULE IN VOLTEKS OPSOMMING) φ = 90° ei h = 3.4516x105Ja−0.855Ku1.344 φ = 45° ei h = 1.4796x105Ja−0.993Ku1.3 φ = 90° l l l ci l l v h x k g 1/ 3 2.05 2 4.61561 109Re 0.364 ν ρ ρ ρ − ⎡ ⎡ ⎛ ⎞⎤ ⎤ = ⎢ ⎢ ⎜ ⎟⎥ ⎥ ⎢ ⎢ ⎜ − ⎟⎥ ⎥ ⎣ ⎣ ⎝ ⎠⎦ ⎦ φ = 45° l l l ci l l v h x k g 1/ 3 1.916 2 3.7233 10 5Re 0.136 ν ρ ρ ρ − ⎡ ⎡ ⎛ ⎞⎤ ⎤ = ⎢ ⎢ ⎜ ⎟⎥ ⎥ ⎢ ⎢ ⎜ − ⎟⎥ ⎥ ⎣ ⎣ ⎝ ⎠⎦ ⎦ Die wiskundig-gemodelleerde demostrasie HPHR is geïnstalleer binne ‘n bestaande lugdroër-sisteem. Drywing van om en by 8.8 kW kon herwin word vanaf die warm-afvalvloeierstroom met ‘n massa vloei van 0.55 kg/s teen ‘n inlaattemperatuur van 51.64 °C en ‘n uitlaattemperatuur van 35.9 °C binne ‘n omgewing van 20 °C. Na aanleiding van hierdie herwinning, kan energiebesparings van tot 32.18 % verkry word. Die HPHR se installasiekoste kan binne ‘n berekende tydperk van ongeveer 3.3 jaar gedelg word deur hierdie besparing. Verdamper- tot kondensator-lengteverhouding, vloeistofvulverhouding en die oriëntasiehoek vereis verdere ondersoek, aangesien daar slegs ‘n akkuraatheid van 25 % verkry is tussen teoretiese voorspellings en praktiese metings.
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Moe, Bjørn Kristian. "Heat Generation by Heat Pump for LNG Plants." Thesis, Norges teknisk-naturvitenskapelige universitet, Institutt for elkraftteknikk, 2011. http://urn.kb.se/resolve?urn=urn:nbn:no:ntnu:diva-14671.

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Abstract The LNG production plant processing natural gas from the Snøhvit field outside Hammerfest in northern Norway utilizes heat and power produced locally with gas turbines. Building a new production train supplied with electricity from the power grid is being evaluated as a possible solution for reducing CO2 emissions from the plant. Buying electricity from the grid rather than producing it in a combined heat and power plant makes it necessary to find new ways to cover the heat loads at the production plant. A project thesis was written in the fall semester 2010 evaluating the possibility of generating the necessary heat with heat pumps. It was concluded that parts of the required heat could be delivered with reasonable efficiencies using heat pumps. Further, a heat pump delivering heat to the CO2-removal system was analyzed. Simulations showed that the required heat load, reaching approximately 62 MW at full production, could be delivered from a heat pump using butane as working fluid. The electrical power consumption for the compressors would be 23.3 MW, giving the heat pump a COP of 2.66. In this master thesis the heat pump suggested earlier is analyzed, focusing on identifying losses. Several possible changes that will enhance the heat pump’s efficiency are suggested. The use of other workings fluids and mixed refrigerants are analyzed as well, using the process simulation software Pro/II. The simulations indicates that the heat pump should be equipped with a flash tank at middle pressure, thereby reducing throttling losses and required mass flows through the evaporators. In addition, the suction gas should be overheated as much as possible. Using mixed refrigerants lowers the efficiency of the heat pump. Finally, two new systems are suggested: One with butane as workings fluid and one with pentane, both with flash tank at middle pressure and superheated suction gas. The pentane-system gives the highest system COP, but requires much bigger compressors than the butane-system. The table shows the most important results. Working fluid Electrical power consumption [MW] Volume flow suction gas [m3/h] COP Butane (C4H10) 18.6 55000 3.35 Pentane (C5H12) 17.5 150000 3.54 The power grid electricity is assumed to have been produced without any CO2 emissions. Covering the heat required by the CO2 removal system with a gas fired furnace would generate CO2 emissions of approximately 120,000 tons per year. Heat pumps are a good solution because they deliver relatively cheap heat without these CO2 emissions.
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Books on the topic "Heat"

1

Griffin, Bettye. The heat of heat. Pleasant Prairie, Wis: Bunderful Books, 2010.

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Ardley, Neil. Heat. New York: New Discovery Books, 1992.

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Carter, Chris. Heat. Oxford: Heineman, 1991.

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Woods, Stuart. Heat. New York: Harper, 1995.

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Field, Andrea R. Heat. New York, NY: Britannica Educational Pub., 2013.

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Press, Modern Curriculum, ed. Heat. 2nd ed. Cleveland, Ohio: Modern Curriculum Press, 1993.

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1964-, Whedon Joss, Greenwalt David, and Copyright Paperback Collection (Library of Congress), eds. Heat. New York: Simon Spotlight Entertainment, 2004.

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Hewitt, Sally. Heat. North Mankato, MN: Stargazer Books, 2006.

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Gordon, Mike, 1948 March 16-, ed. Heat. Hove: Wayland, 1995.

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Barrett, Jean. Heat. New York: Silhouette Books, 1991.

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Book chapters on the topic "Heat"

1

Skillington, Tracey. "Heat, Heat Wave." In Handbook of the Anthropocene, 145–49. Cham: Springer International Publishing, 2023. http://dx.doi.org/10.1007/978-3-031-25910-4_23.

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Theisler, Charles. "Heat Intolerance/Heat Stroke." In Adjuvant Medical Care, 162–63. New York: CRC Press, 2022. http://dx.doi.org/10.1201/b22898-172.

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Wellner, Marcel. "Heat." In Elements of Physics, 209–25. Boston, MA: Springer US, 1991. http://dx.doi.org/10.1007/978-1-4615-3860-8_10.

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Webb, Benjamin L. J., David Holmes, Chun Li, Jin Z. Zhang, and Matthew T. Lloyd. "Heat." In Encyclopedia of Nanotechnology, 1021. Dordrecht: Springer Netherlands, 2012. http://dx.doi.org/10.1007/978-90-481-9751-4_100284.

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Gooch, Jan W. "Heat." In Encyclopedic Dictionary of Polymers, 359. New York, NY: Springer New York, 2011. http://dx.doi.org/10.1007/978-1-4419-6247-8_5824.

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Bolton, William. "Heat." In Engineering Science, 141–60. Seventh edition. | Abingdon, Oxon; New York, NY: Routledge, 2021.: Routledge, 2020. http://dx.doi.org/10.1201/9781003093596-8.

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Archer, W. G. "Heat." In Love Songs of Vidyāpati, 129. London: Routledge, 2021. http://dx.doi.org/10.4324/9781003104216-91.

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Heß, Markus, and Valentin L. Popov. "Heat Transfer and Heat Generation." In Method of Dimensionality Reduction in Contact Mechanics and Friction, 115–30. Berlin, Heidelberg: Springer Berlin Heidelberg, 2014. http://dx.doi.org/10.1007/978-3-642-53876-6_8.

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Kays, Stanley J. "Heat, Heat Transfer, and Cooling." In Postharvest Physiology of Perishable Plant Products, 457–507. Boston, MA: Springer US, 1991. http://dx.doi.org/10.1007/978-1-4684-8255-3_8.

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Taylor, Sterling A., and Ray D. Jackson. "Heat Capacity and Specific Heat." In SSSA Book Series, 941–44. Madison, WI, USA: Soil Science Society of America, American Society of Agronomy, 2018. http://dx.doi.org/10.2136/sssabookser5.1.2ed.c38.

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Conference papers on the topic "Heat"

1

Xiong, Shaomin, Erhard Schreck, and Sripathi Canchi. "Head Disk Spacing Effect on Heat Transfer in Heat Assisted Magnetic Recording." In ASME 2017 Conference on Information Storage and Processing Systems collocated with the ASME 2017 International Technical Conference and Exhibition on Packaging and Integration of Electronic and Photonic Microsystems. American Society of Mechanical Engineers, 2017. http://dx.doi.org/10.1115/isps2017-5437.

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Heat transfer at nanometer scale attracts a lot of interest from both academia and industries. The hard disk drive (HDD) industry cares about the heat transfer between the head and disk, as several heating and thermal sensing elements are integrated into the HDD system. Understanding the heat transfer mechanism and its dependency on spacing becomes very critical for heat assisted magnetic recording (HAMR). In this paper, we propose a new method to study the head disk spacing effects on heat transfer by introducing a small perturbation to the spacing while maintaining the heating source unchanged. The dependency of heat transfer on the nanoscale spacing provides insights to the understanding of heat transfer mechanisms inside the nanoscale gap.
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Cheng, Qilong, and David B. Bogy. "Experimental Study of Nanoscale Head-Disk Heat Transfer In Heat-Assisted Magnetic Recording." In ASME 2021 30th Conference on Information Storage and Processing Systems. American Society of Mechanical Engineers, 2021. http://dx.doi.org/10.1115/isps2021-62275.

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Abstract To study the nanoscale heat transfer and laser-related protrusions in heat-assisted magnetic recording (HAMR), we performed static touchdown experiments between HAMR waveguide heads and non-rotating media such as a silicon wafer and a recording disk with an AlMg substrate. During the static touchdown, the laser element is energized with DC current and the embedded contact sensor (ECS) is used to monitor the head temperature. The experimental results show that the thermal fly-height control (TFC) touchdown power decreases with increasing laser current. Meanwhile, the head temperature increases due to the laser heating. From this the ECS resistance rise induced by the laser is extracted. The results show that the silicon wafer dissipates heat effectively under the laser exposure, while the AlMg-substrate disk undergoes a higher temperature rise, which in turn heats the head.
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Glavachka, V., V. G. Kiselev, Yu N. Matveev, M. I. Rabetsky, and P. Schtulz. "UNIFIED HEAT PIPE HEAT EXCHANGERS USED FOR HEAT RECOVERY." In Heat Pipe Technology: Volume 2. Materials and Applications. Connecticut: Begellhouse, 2023. http://dx.doi.org/10.1615/ihpc1990v2.570.

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Xue-Jun, Yu, Yang Tiande, Pang Cheng, Chang Shaoyong, and Wu Jianmin. "Regulation and Heat Tolerance by Men in Heat Before and After Head-Down Tile." In International Conference On Environmental Systems. 400 Commonwealth Drive, Warrendale, PA, United States: SAE International, 2005. http://dx.doi.org/10.4271/2005-01-2999.

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Sunayama, Noboru. "Heat Transfer/Thermal Analysis for Cylinder Head." In International Congress & Exposition. 400 Commonwealth Drive, Warrendale, PA, United States: SAE International, 1991. http://dx.doi.org/10.4271/910301.

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Satyanarayana, Janardhan H., and Keshab K. Parhi. "HEAT." In the 33rd annual conference. New York, New York, USA: ACM Press, 1996. http://dx.doi.org/10.1145/240518.240520.

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North, Mark T., David B. Sarraf, John H. Rosenfeld, Yuri F. Maidanik, and Sergey Vershinin. "High heat flux loop heat pipes." In AIP Conference Proceedings Volume 387. ASCE, 1997. http://dx.doi.org/10.1063/1.52046.

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Vasiliev, Leonard L., and V. V. Khrolenok. "HEAT TRANSFER IN ROTATING HEAT PIPES." In Heat Pipe Technology: Volume 1. Fundamentals and Experimental Studies. Connecticut: Begellhouse, 2023. http://dx.doi.org/10.1615/ihpc1990v1.290.

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Novomestský, Marcel, Andrej Kapjor, Štefan Papučík, and Ján Siažik. "Heat pipe thermosyphon heat performance calculation." In THE APPLICATION OF EXPERIMENTAL AND NUMERICAL METHODS IN FLUID MECHANICS AND ENERGY 2016: XX. Anniversary of International Scientific Conference. AIP Publishing LLC, 2016. http://dx.doi.org/10.1063/1.4953731.

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McCullough, Charles R., Scott M. Thompson, and Heejin Cho. "Heat Recovery With Oscillating Heat Pipes." In ASME 2013 International Mechanical Engineering Congress and Exposition. American Society of Mechanical Engineers, 2013. http://dx.doi.org/10.1115/imece2013-66241.

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Waste-heat recovery applied in HVAC air systems is of interest to increase the energy efficiency of residential, commercial and industrial buildings. In this study, the feasibility of using tubular-shaped oscillating heat pipes (OHPs), which are two-phase heat transfer devices with ultra-high thermal conductivity, for heat exchange between counter-flowing air streams (i.e., outdoor and exhaust air flows) was investigated. For a prescribed volumetric flow rate of air and duct geometry, four different OHP Heat Exchangers (OHP-HEs) were sized via the ε-NTU method for the task of sub-cooling intake air 5.5 °C (10 °F). The OHP-HE tubes were assumed to have a static thermal conductivity of 50,000 W/m·K and only operate upon a minimum temperature difference in order to simulate their inherent heat transport capability and start-up behavior. Using acetone as the working fluid, it was found that for a maximum temperature difference of 7°C or more, the OHP-HE can operate and provide for an effectiveness of 0.36. Pressure drop analysis indicates the presented OHP-HE design configurations provide for a minimum of 5 kPa. The current work provides a necessary step for quantifying and designing the OHP for waste heat recovery in AC systems.
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Reports on the topic "Heat"

1

Lam, P. S., and R. L. Sindelar. Heat exchanger, head and shell acceptance criteria. Office of Scientific and Technical Information (OSTI), September 1992. http://dx.doi.org/10.2172/10173694.

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2

Stinn, John P., and Hongwei Xin. Heat Lamp vs. Heat Mat as Localized Heat Source in Swine Farrowing Crate. Ames (Iowa): Iowa State University, January 2014. http://dx.doi.org/10.31274/ans_air-180814-1213.

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3

Armstrong, Lawrence E. Heat Exhaustion. Fort Belvoir, VA: Defense Technical Information Center, June 1989. http://dx.doi.org/10.21236/ada212128.

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4

Rekos, Jr, N., and E. Parsons, Jr. Heat engines. Office of Scientific and Technical Information (OSTI), September 1989. http://dx.doi.org/10.2172/6905384.

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5

Harris, Ben, and Alan Walker. Heat pumps. Parliamentary Office of Science and Technology, July 2023. http://dx.doi.org/10.58248/pn699.

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6

Shen, D. S., R. T. Mitchell, D. Dobranich, D. R. Adkins, and M. R. Tuck. Micro heat spreader enhanced heat transfer in MCMs. Office of Scientific and Technical Information (OSTI), December 1994. http://dx.doi.org/10.2172/10107765.

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7

Culver, G. DHE (downhole heat exchangers). [Downhole Heat Exchangers (DHE)]. Office of Scientific and Technical Information (OSTI), November 1990. http://dx.doi.org/10.2172/6304383.

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8

Hodgdon, James A. Body Heat Storage and Work in the Heat. Fort Belvoir, VA: Defense Technical Information Center, May 2004. http://dx.doi.org/10.21236/ada430223.

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9

Maynard, Julian D. Stack/Heat-Exchanger Research for Thermoacoustic Heat Engines. Fort Belvoir, VA: Defense Technical Information Center, June 1996. http://dx.doi.org/10.21236/ada327871.

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10

Hodgdon, James A. Body Heat Storage and Work in the Heat. Fort Belvoir, VA: Defense Technical Information Center, May 2003. http://dx.doi.org/10.21236/ada423463.

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