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Dissertations / Theses on the topic 'Stem heating'
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Jones, Joshua Levi. "Development of an advanced stem heating model /." Diss., CLICK HERE for online access, 2003. http://contentdm.lib.byu.edu/ETD/image/etd231.pdf.
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Jones, Joshua L. "Development of an Advanced Stem Heating Model." BYU ScholarsArchive, 2003. https://scholarsarchive.byu.edu/etd/88.
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A new one-dimensional heat conduction model for predicting stem heating during fires is presented. The model makes use of moisture and temperature dependent thermal properties for bark and wood. Also, the thermal aspects of the processes of bark swelling, desiccation, and devolatilization are treated in an approximate fashion. Simulation with a surface flux boundary condition requires that these phenomena be accounted for. Previous models have used temperature-time boundary conditions, which prevents them from being directly coupled to fire behavior models. This model uses a flux-time profile for its boundary condition, making it possible to eventually couple it to fire behavior models. Cambial mortality predictions are made through the incorporation of a cell mortality model. The model was developed and validated with laboratory experiments on four species.
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Truvé, Malin, and Johanna Kilegran. "New applications of Antrad Medical's thawing technology : Applications within the clinical and laboratory segment." Thesis, KTH, Skolan för teknik och hälsa (STH), 2016. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-190778.
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Antrad Medical has developed an ultra-fast blood plasma thawing device named UFT100. The method is based on thawing with an oscillating electrical field and unlike water baths it is a dry method. Fast and homogeneous thawing is achieved. This project investigates new possible applications where this thawing technology could be used within the clinical and laboratory segment. The aim was to identify existing thawing and heating methods for a substance that can be improved and potentially replaced with the UFT100. Data has been collected through literature research and interviews with Antrad Medical and specialists working in Sweden. The specialists are working within the clinical and laboratory field. A number of criteria for establishment of the UFT100 were set up and used as a tool for evaluation. The substances investigated during this project were infusion medicine, embryos, substance in a sampling tube, protein based pharmaceuticals, stem cells for transplantation and research, biobank sampling tubes, cryoprecipitate, human hepatocytes, live vaccines, API, BDS, intermediate and antibodies. Two applications within the clinical area are found probable, stem cells and cryoprecipitate. Further investigation for human hepatocytes, API, BDS, intermediate and pharmaceuticals is needed.Antrad Medical har utvecklat en ultra-snabb blodplasmaupptinare kallad UFT100. Det är till skillnad från vattenbad en torr metod baserad på upptining med hjälp av oscillerande elektriska fält. Genom detta uppnås snabb och homogen upptining. Detta projekt undersöker nya möjliga kliniska- och laboratorietillämpningar för upptiningstekniken. Målet var att identifiera substanser vars nuvarande upptining- och uppvärmningsteknik kan förbättras och kanske ersättas med UFT100. Data har samlats in genom litteratursökning och genom intervjuer med Antrad Medical och specialister som arbetar i Sverige. Specialisterna arbetar inom kliniska områden och laboratorieverksamheter. Ett antal kriterier för etablering av UFT100 sattes upp och användes för utvärdering. Substanserna som undersöktes under projektets gång var infusionsmedicin, embryon, innehåll i ett provrör, proteinbaserade läkemedel, stamceller för transplantation och forskning, biobank-provrör, kryoprecipitat, humana hepatocyter, levande vaccin, aktiva substanser, läkemedelssubstanser, intermediat och antikroppar. Två tillämpningar inom det kliniska området ses som möjliga, stamceller och kryoprecipitat. Humana hepatocyter, aktiva substanser, läkemedelssubstanser och intermediat behöver undersökas vidare.
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Patel, Mandar Ranchhod. "STEAM, DIELECTRIC HEATING AND COPPER SULFATE TREATMENT OF INSHELL PECANS." MSSTATE, 2008. http://sun.library.msstate.edu/ETD-db/theses/available/etd-07102008-155952/.
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Water and a copper sulfate (CSL) solution at 27, 57 and 88°C; steam pasteurization and dielectric heating were analyzed on their effect in reducing microbial load (APC) and Salmonella Typhimurium on inshell pecans (Carya illinoinensis). The CSL solution (more effective than water alone) reduced APC by 1.5 (300 s), 2 (60 s) and 4.0 (60 s) log CFU/g at 27, 57 and 88°C, respectively; and Salmonella by 3.0 log at 27°C in 60 s. Steam reduced APC by 3.7 log in 180 s and Salmonella by 4.0 log CFU/g in 30 s. Dielectric treatment reduced APC by 3.0 log and Salmonella by 4.5 log CFU/g in 60 s. Most treatments had no effect on the pecan shell or the nut quality, except for dielectric heating, which gave a slight "roasted" or "burnt" flavor to the nuts. This study showed that a proper antimicrobial-hot water treatment, steam or dielectric heating will be effective in "pasteurizing" pecans, resulting in a safe and wholesome product.
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Kubanek, Gordon J. "Heavy oil processing in steam and hydrogen plasmas." Thesis, McGill University, 1985. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=63281.
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Wu, Haijun Walker Paul N. "Numerical model for isobaric steam heating of initially saturated packed beds." [University Park, Pa.] : Pennsylvania State University, 2009. http://etda.libraries.psu.edu/theses/approved/WorldWideIndex/ETD-4300/index.html.
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Hurley, James Thomas. "Analysis of steam and hydronic compartment heating systems aboard U.S. Coast Guard 140 foot WTGB class cutters." Thesis, Monterey, Calif. : Springfield, Va. : Naval Postgraduate School ; Available from National Technical Information Service, 1996. http://handle.dtic.mil/100.2/ADA315405.
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Řezníček, Jan. "Návrh kotle na spalování slámy,sytá pára 143°C 3MW, a pro CZT 6MW." Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2013. http://www.nusl.cz/ntk/nusl-230879.
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The work is focused on the design heat generation source in my chosen location. The entire facility should be designed to meet the basic requirements of the client. The primary objective of this work is alternatively propose solutions to perform basic balance calculations and determine the performance of each device. Based on the location selected diagram to produce annual heat needs and recommend the best possible solution.
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Hrubý, Vojtěch. "Teplárna na biomasu." Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2010. http://www.nusl.cz/ntk/nusl-228995.
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The content of this dissertation is to utilize foundations of heat consumption in Velký Karlov and to propose and replace the main district heating plant into the heating plant which uses biomass as its fuel. With techno-economic evaluation of the annual operating central heating plant evaluate the suitability of using a steam turbine or steam engine. The proposal for a steam turbine is chosen by the preliminary calculation. There are showed suitable possibilities of working and its evaluation considered to return period.
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Su, Heyin. "Modeling of Proposed Changes to SIUC Central Heating, Air-Conditioning, and Power Plant Incorporating Variable Frequency Drive (VFD) and High Efficiency Turbine." OpenSIUC, 2011. https://opensiuc.lib.siu.edu/theses/708.
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Currently, the Southern Illinois University Carbondale (SIUC) power plant produces steam at high pressure to drive a high pressure (HP) turbine to make a portion of the electrical power needed by campus, then using 969 kPa (125 psig) steam to provide hot water all year, heat buildings, and to operate a low pressure (LP) turbine that powers the compressor of the central air conditioning (A/C) system. In the proposed system, the HP turbine is replaced by a much higher efficiency, multi-level turbine, the LP turbine is replaced with a motor and Variable Frequency Drive (VFD), and a cooling tower is added to condense more possible steam. This thesis has provided computer models to evaluate the economical feasibility of the proposed system, which are written by using Engineering Equation Solver (EES) software. The results of the study are presented in two cases. Case 1 examines the same amount of coal use between current and proposed systems, while Case 2 exames operating the high pressure boiler at the maximum rate. The results are a cost savings of $1,921,000 and $3,604,000 with payback periods of 4 and 2.2 years for Case 1 and Case 2, respectively. The annual primary energy saved and CO2 reduction from this modification was 200,000 GJ and 564,814 moles, respectively.
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Pic, Axel. "Numerical and experimental investigations of self-heating phenomena in 3D Hybrid Bonding imaging technologies." Thesis, Lyon, 2019. http://www.theses.fr/2019LYSEI054.
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Dans cette thèse, les phénomènes d’auto-échauffement ont été étudié pour guider la conception de circuits intégrés 3D de nouvelle génération. Grâce à des études expérimentales et numériques, la dissipation thermique dans des imageurs 3D par collage hybride a été analysée et l’impact de l’augmentation de température résultante a été évalué. Premièrement, afin de développer des modèles précis, les propriétés thermiques des matériaux utilisés dans les circuits intégrés ont dû être déterminées. Différents films minces diélectriques impliquant des oxydes, des nitrures et des composés low-k ont été étudiés. Pour ce faire, la microscopie thermique à sonde locale (SThM) et la méthode électrothermique 3ω, sensibles à la conductivité thermique effective faible et élevée, ont été mises en œuvre. Dans un deuxième temps, des modèles éléments finis de circuits intégrés 3D ont été développés. Une méthode numérique nécessitant homogénéisations et approches multi-échelles a été proposée pour surmonter des grands rapports de forme inhérents à la microélectronique. La procédure numérique a été validée en comparant les calculs et les mesures expérimentales effectuées par SThM, la thermométrie résistive et la microscopie infrarouge sur une puce de test par collage hybride simplifiée. Il a été montré que la dissipation de chaleur est principalement limitée par la conductance du puit thermique ainsi que les pertes par l'air. Enfin, des études numériques et expérimentales ont été réalisées sur des imageurs 3D par collage hybride fonctionnels. Le champ de température a été mesuré par SThM et comparé aux calculs par éléments finis à la surface de la matrice. Les résultats numériques ont montré que la température de la surface des pixels est égale à celle du Front-End-Of-Line de l’imageur. L'influence de l'échauffement sur les performances optiques de l'imageur a été déduite de cette analyse. Cette étude a permis également d'évaluer les différentes méthodes numériques et expérimentales pour la caractérisation de la dissipation de chaleur en microélectroniqueIn this PhD thesis, self-heating phenomena are studied for guiding the design of next-generation 3D Integrated Circuits (ICs). By means of experimental and numerical investigations, associated heat dissipation in 3D Hybrid Bonding imagers is analyzed and the impact of the resulting temperature rise is evaluated. First, in order to develop accurate models, the thermal properties of materials used in ICs are to be determined. Different dielectric thin films involving oxides, nitrides, and low-k compounds are investigated. To do so, Scanning Thermal Microscopy (SThM) and the 3ω electrothermal method, sensitive to low and large effective thermal conductivity, are implemented. In a second step, finiteelement models of 3D ICs are developed. A numerical method involving homogenization and a multiscale approach is proposed to overcome the large aspect ratios inherent in microelectronics. The numerical procedure is validated by comparing calculations and experimental measurements performed with SThM, resistive thermometry and infrared microscopy on a simplified Hybrid Bonding test chip. It is shown that heat dissipation is mainly limited by the heat sink conductance and the losses through air. Finally, numerical and experimental studies are performed on fully-functional 3D Hybrid Bonding imagers. The temperature field is measured with SThM and compared with finite-element computations at the die surface. The numerical results show that the temperature of the pixel surface is equal to that of the imager Front-End-Of-Line. The influence of the temperature rise on the optical performance of the imager is deduced from the analysis. The study also allows assessing the various numerical and experimental methods for characterizing heat dissipation in microelectronics
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Peterka, Lubomír. "Návrh teplárny s pístovým parním motorem." Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2010. http://www.nusl.cz/ntk/nusl-228961.
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The final thesis deals with the heating plant with piston steam engine design according to heat consumption background in the location of Velky Karlov and with the design of a heating scheme including its explicit parameters. Further on it deals with the possibilities of the heating plant output regulation and with the solution of natural gas and biomass heating plant operations aside the heating period.
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Stromský, Tomáš. "Studium slinování pokročilých keramických materiálů." Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2012. http://www.nusl.cz/ntk/nusl-230343.
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The influence of various pressure-less heating schedules (CRH - Constant Rate of Heating, TSS - Two Step Sintering, RCS – Rate Controlled Sintering) on the final microstructure of cubic zirconia ceramics was studied in this master´s thesis. There were used nanopowders ZrO2 (stabilized with 8 mol.% Y2O3) with initial particle size 80 nm (TZ-8Y) and 140 nm (TZ-8YSB). Powders were cold isostatically pressed and pressure-less sintered in air by different heating regimes. It was found that for both studied materials the modification of conventional sintering (CRH) using lower sintering temperatures and longer sintering dwell times can result in samples with finer microstructure. For example, the sintering of TZ-8YSB ceramics at a relatively low temperature (1270 °C) but for very long time (60 h) led to ceramics with the same final density (99,25 % of theoretical density) and almost identical grains (1,31 m vs. 1,27 m) in compare with TSS (1440 °C/ 1290 °C/ 15 h). On the other hand, RCS method showed no positive effect on the microstructure of both materials in comparison with CRH method. The obtained results indicate that the microstructure of c-ZrO2 ceramics can be influenced rather in its third sintering stage (by CRH and TSS methods) than in the second sintering stage (by RCS method).
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Pekárek, Michal. "Návrh elektricky otápěného parního vyvíječe." Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2021. http://www.nusl.cz/ntk/nusl-443183.
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This master’s thesis is focused on the design of electric steam generator for superheated steam. Using heating cartridge is the easiest way how to make a saturated or superheated steam. This device is part of gasification reactor, which is used for experimental purposes. The thesis includes schematic involvement of technology. Technology contains evaporator and superheater. The evaporator is calculated as pool boiling. The superheater is design for steam flowing through heating cartridge bundle. At the end of the thesis are made projection drawings, which are based on the calculations.
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Bartusek, Jiří. "Dynamika topných ploch a těles včetně regulačních ventilů." Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2014. http://www.nusl.cz/ntk/nusl-231397.
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This thesis is theoretically described heating surfaces, radiators and regulation valves. There are also described their features, advantages and disadvantages and division according to design. The aim of the work is determine the dynamics characteristics of heating surfaces and radiators including control valves, which are parts of measurement panel. Based on the measurement are determined appropriate characteristics of which are calculated values for regulating. The result of this study can serve as a guide to the practical measurement method of dynamics characteristics of the real-working heating systems, or serve as a template for the settings according to the measured data.
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Venturi, Elisa. "Dynamic simulation and analysis of a Passive House case study with direct PV system for heating and domestic hot water production." Master's thesis, Alma Mater Studiorum - Università di Bologna, 2018. http://amslaurea.unibo.it/16590/.
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Different heating systems for space heating and domestic hot water (DHW) preparation are investigated with respect to their energy efficiency. In particular, a case study of a multi-storey Passive House (called An-der-Lan) is analysed by means of dynamic simulations.
The first part of dynamic simulations focuses on the comparison of the UA and RC models for a simple office located in Rome. This is a case study from the project IEA SHC T56 – System Simulation Models. In particular, attention is put on the influence of the thermal capacity. Assuming the RC model as the reference case, variants of the UA model with different percentages of the thermal capacity are simulated, in order to find out the most similar to the RC model. The same investigation is carried out for the An-der-Lan building. In general, it is not possible to identify the best UA model, because for every considered quantity, the minimum difference between the UA and RC model is got for a different percentage of the thermal mass.
The second part of dynamic simulation focuses on the comparison among different systems for heating and DHW preparation. The realized system is direct electric heating for both space heating and DHW preparation. It is denoted as the reference Case1 and it is compared against alternative solutions. Case2 is based on a central air/water heat pump system for both heating and DHW production. A sensitivity analysis study is conducted. Finally, Case3 and Case4 are a mix of the previous two cases.
Results show that Case2 is the best in terms of electric energy required from the grid, although it is the system with the highest thermal losses. Furthermore, the PV system only in the south façade is not sufficient to cover the energy required in neither of the cases.
Finally, annual, monthly, daily, hourly and 10 minutes balances are compared. Results show the importance of smaller time step in balances between required and produced energy, in order to have more precise results.
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Kalina, Leoš. "Návrh typu a zapojení parní turbíny pro konkrétní lokalitu." Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2019. http://www.nusl.cz/ntk/nusl-400488.
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This master's thesis is deals with type designing and implementing the steam turbine to the machine part of heat plant in reconstruction. The thesis consists of two parts. First part is theoretical explanation of the heating industry, steam turbines, thermal cycles and components of thermal power plants. Second part of the thesis describes the design and calculation of thermal diagrams based on turbine parameters, which were provided from Tenza, a.s. tender. There is a simplified calculation of technical-economic study in the conclusion of the thesis. The thesis output is recommendation of single final implementation solution for customer.
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Rak, Vítek. "Rekonstrukce turbogenerátoru TG 5 v Elektrárně Opatovice." Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2018. http://www.nusl.cz/ntk/nusl-378635.
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This thesis discusses the reconstruction of the turbogenerator TG5 of the Elektrárny Opatovice and introduces options of technical solutions for power central of combined heat and electricity production. First section describes the differences between back-pressure and condensing turbines. Next section briefly introduces the company Elektrárny Opatovice a.s. with the description of the current back-pressure turbine TG5, which is near end of it life cycle and is to be reconstructed in following years. Based on the technical-economic analysis of the operation of the current TG5, possible benefits of new technical solutions are proposed.
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Payne, Nathaniel M. "Development of a Combined Thermal Management and Power Generation System using a Multi-Mode Rankine Cycle." Wright State University / OhioLINK, 2021. http://rave.ohiolink.edu/etdc/view?acc_num=wright1622657194320193.
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Filoušová, Natálie. "Parní turbína v paroplynovém cyklu." Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2017. http://www.nusl.cz/ntk/nusl-318750.
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Diploma thesis named Steam turbine in the combi cycle deals with design of low pressure part of three-body turbine and it’s lateral outlet throat to the air condenser. Before the design itself, the thermal schema of entire turbine is calculated. Than follows the detail draft, the strength calculations are included as well. Turbine has any technological consumption of steam or any regenerativ consumption. Turbine will be suplly to Panama. The thesis includes following drawings: cut of flowing part, design of outlet throat and fixing of inner body in outer body of low pressure part. The diploma thesis is created for Doosan Škoda Power company.
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Pizzimenti, Karen Viola. "Sensory quality and energy use related to heating beef stew in bulk or in individual portions in various pieces of institutional foodservice equipment after varying storage periods and processing in retort pouches and air tight plastic bags." The Ohio State University, 1989. http://rave.ohiolink.edu/etdc/view?acc_num=osu1342107343.
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Bratasanu, Ion. "Modélisation et étude d'un réseau de chauffage arborescent en régime statique et dynamique." Cachan, Ecole normale supérieure, 1994. http://www.theses.fr/1994DENS0004.
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Modélisation d'un réseau de chauffage urbain arborescent, alimente par plusieurs chaufferies. En régime statique, résolution numérique du système d'équations algébriques du réseau. Étude du problème d'optimisation pour la recherche du pilotage optimal du réseau, et résolution numérique par une méthode de dualité. En régime dynamique, étude d'existence de solution pour le système d'équations aux dérivées partielles du réseau. A noter que la thèse étudie uniquement le cas d'un réseau de chauffage urbain arborescent, qui utilise de l'eau chaude surchauffée. On n'étudie pas le cas d'un réseau de chauffage urbain maille, qui utilise de l'eau chaude surchauffée ou de la vapeur
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Ptáček, Ondřej. "Návrh dvoutlakého vertikálního kotle na odpadní teplo za plynovou turbínou na zemní plyn." Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2017. http://www.nusl.cz/ntk/nusl-319246.
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This diploma thesis deals with proposal of a two-lane vertical boiler using the waste heat after gas turbine. In the first part the heat calculation has been done followed by the arrangement of particular heat exchange surfaces and the drawing of real saw diagram. There are also dimensions of drums, inlet and outlet pipes and transfer pipelines drafted. Furthermore, I have listed the materials that are used for casing the boiler and pipelines. Finally, the boiler loss is calculated and the boiler hydraulic calculation is performed. The supplement contains a boiler drawing.
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Telecký, Jakub. "Laboratorní úloha s regulací teploty." Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2020. http://www.nusl.cz/ntk/nusl-416636.
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This work deals with regulation and procedures that can be used for this. The theoretical part therefore presents the basic concepts of automation and controllers. The main part is the practical part. The purchased system consists of a regulated system, which must be set up correctly. Using system identification and known procedures, sample examples of how to best set the controller are compiled. The result is a sample laboratory task that automation students can try and gain experience with methods of setting up the controller.
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Maršík, Jaroslav. "Dvoutlaký horizontální kotel na odpadní teplo (HRSG)." Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2015. http://www.nusl.cz/ntk/nusl-232157.
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The Master’s thesis dealing with design of heat recovery steam generator with two pressure levels is split into nine sections. The first section describes the design and the layout of HRSG. The second part deals with heat calculation. The third section deals with design of flue-gas duct. The fourth part describes designs of individual heating surfaces, including steam superheaters, vaporizers and economizer. Next section shows the real temperature diagram and choice of the materials. The seventh section describes the calculation of outer pipelines and the eighth part deals with the drums design. The last section deals with the calculation of draft loss of steam generator.
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Khabrana, Ahmed, and Jaber Ageeli. "Producing Electricity in Power Plant." Thesis, Blekinge Tekniska Högskola, Institutionen för tillämpad signalbehandling, 2015. http://urn.kb.se/resolve?urn=urn:nbn:se:bth-1979.
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Abstract This Bachelor thesis has been written at the Blekinge Institute of Technology. The thesis describes electricity production in Shoaiba Steam Power plant in Saudi Arabia. Shoaiba Power Plant is located 100 km South of Jeddah city in Saudi Arabia. Total power production ability reaches 4400 MW. Shoaiba Power Plant has two stages and is constructed with 11 units, each unit produces 400 MW at line voltage 24 kV and line current 16 kA. Main pieces of equipment and their function in the station are as follows: A Steam Generator (boiler), produces steam by burning natural gas or crude oil in the furnace. The steam is superheated and is passed into a steam turbine, which converts the thermal energy of the steam into mechanical power, in form of rotary motion. The turbine drives a generator, which converts the rotary energy of the turbine into electric power. Steam generator, steam turbine and electrical generator are components that are described in the thesis. When the flow of steam to the turbine is controlled, then the amount of thermal energy that changes to mechanical energy in the steam turbine is controlled. The electrical generator is where the final energy conversion takes place. The mechanical energy from the turbine is converted by the generator into electrical energy, which is transmitted to the service area by help of electrical transmission lines. The plant cycle is an essential part of the energy flow path. Without the plant cycle, the conversion of thermal energy into mechanical energy would not occur, The plant cycle is a closed loop that allows the same water to be used over and over again. Always, the power plants are situated far from residential areas and located outside cities and close to the sea, because the steam is produced from seawater. The advantages of the steam power stations are as follows: They can produce high amounts of electrical energy from small amounts of fuel. They have low initial costs, obstetrics and maintenance costs are not high, and the stations do not need much space to be built and they have usually high capacity. The disadvantages of steam stations are the following: They cause environmental pollution, they have low efficiency, and require very big quantities of cooling water, and the stations must be built away from populated areas.Conclusion: Converting in steam power plant is one of many ways to produce electrical energy in the world. It can be done in any country because it can be done with different chemical sources. In Saudi Arabia we use oil, because it easier and cheaper than any other chemical source for us. As any country would use what is better for them. The thesis has described circulation system in Shoaiba power plant by converting chemical energy to thermal energy in the boiler, then the turbine converts thermal energy to mechanical energy. Then the mechanical energy is converted to electrical energy in the generator. The advantages of the steam stations are as follows: production of high amounts of electrical energy from small amounts of fuel, low cost of the initial costs, obstetrics and maintenance costs are not high, the station does not need much space to build and they are usually high capacity. The disadvantages of steam stations are the following: environmental pollution, low efficiency, requires very big amounts of cooling water, and these stations must be built away from population areas.
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Brabec, Vít. "Parní turbina jako točivá redukce." Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2011. http://www.nusl.cz/ntk/nusl-229826.
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The dissertation analyses a possibility to install a steam turbine for steam reduction in the heating plant with a combined cycle, Červený Mlýn. In the first part of this work the constituent parts of Červený Mlýn plant are briefly described. Basic information is included about two considered solutions to the steam turbine for steam reduction. Then the thermic diagram of the whole heating plant and the heat exchanger station itself is presented. On the basis of the given values of the heat required in the hydrothermal system, duration of the steam flow through both variants of the steam turbine for steam reduction is determined. The thermodynamic calculation of the steam turbine for steam reduction is aimed at determination of the power output and its comparison with the power outputs of the steam turbines for steam reduction considered. In the economical profitability calculation, basic economical quantities are given for both the solutions and the more suitable solution is recommended.
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Svoboda, Adam. "Simulátor GateCycle a jeho aplikace." Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2018. http://www.nusl.cz/ntk/nusl-387732.
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Hlavná náplň tejto práce je oboznámenie so softvérom GateCycle od spoločnosti General Electric a jeho následná aplikácia na simulovanie industriálneho parného kotla produkujúceho 120 t pary za hodinu. Dizajn práce je vo forme výučbového materiálu, ktorý môže byť použitý vo výuke predmetu procesného inžinierstva zameraného na simulačné softvéry. Prvá časť práce je venovaná krátkej teórii o simulačných softvéroch a uvádza niekoľko najznámejších procesných inžinierskych simulačných programov. Druhá časť je napísaná formou GateCycle manuálu. V krátkosti predstavuje pracovné prostredie a rozhranie softvéru, demonštruje ako vytvoriť a spustiť simulačný model, zadať vstupné dáta a vytvoriť reporty. Tretia časť práce je praktická, vybraný industriálny parný kotol je prezentovaný a následne je vybudovaný jeho simulačný model. Táto časť je vytvorená vo forme príručky „krok za krokom“ vysvetľujúcej ako vytvoriť model kotla a aké dáta boli zadané do jednotlivých procesných aparátov. Kotol je simulovaný v 3 režimoch, využívajúc zemný plyn, ťažký vykurovací olej, či dechtovú vykurovaciu zmes ako palivo a je prevádzkovaný za mierne rozličných procesných podmienok. V závere sú vypočítané spotreby paliva porovnané s reálnymi prevádzkovými dátami a je vyhodnotená presnosť výpočtov softvéru GateCycle v týchto konkrétnych prípadoch.
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Med, Lukáš. "Návrh dvoutlakého horizontálního kotle na odpadní teplo." Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2016. http://www.nusl.cz/ntk/nusl-241924.
Full textAbstract:
This master's thesis deals with thermal calculation and design of proportions of calorific components of a heat recovery steam generator (HRSG), which is placed behind a combustion turbine, for given parameters of exhaust gases and requested parameters of steam. In the first chapters is described the design, layout of HRSG and the thermal calculation. The next parts deal with the design of flue-gas duct and each individual heating surface. Next section shows computations of dimensions of drums, flooding pipes, transferring pipes and all other outer pipes. The chosen materials are described in one of the last chapters and the last chapter deals with calculation of draft loss of steam generator.
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Slíva, Karel. "Návrh dvoutlakého horizontálního kotle na odpadní teplo." Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2016. http://www.nusl.cz/ntk/nusl-254297.
Full textAbstract:
The focus of this thesis is a proposal of a horizontal dual-pressure heat recovery steam generator. The introductory part includes thermal calculation, as well as a design of the layout and a design of the heat transfer surfaces and the layout of the boiler. Individual chapters are broken down according to the outline of the proposal for the arrangement of the heating surfaces, according to the parameters of the flue gas and steam. The master thesis contains a scheme of a real heat transfer temperature diagram and it also includes the calculation of connecting and downcomer pipes and drums. The final part describes the calculation of the boiler draft loss. The main idea of the thesis is accompanied by the technical documentation of the drawing of the boiler.
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Hammarström, Anton. "Utvärdering av potential för värmeåtervinning från laborationsutrustning : Möjligheten att använda en kylvattenbassäng som termiskt säsongslager." Thesis, Mittuniversitetet, Avdelningen för kemiteknik, 2018. http://urn.kb.se/resolve?urn=urn:nbn:se:miun:diva-34309.
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HETA utbildningar i Härnösand har ett ångkraftverk för undervisningssyfte som kyls ner med vatten från en underjordisk bassäng på cirka 329 m³. Syftet med detta examensarbete har varit att undersöka hur bassängen med spillvärmen från kraftverket kan användas som ett säsongslager i kombination med en befintlig 7,8 kW värmepump för att värma upp maskinhallen i deras laboratoriebyggnad. Ett kalkylark skapades i Microsoft Excel för att kunna genomföra beräkningarna. Då mätdata saknades skapades ett simulerat scenario baserat på temperaturstatistik och körschema för kraftverket från år 2017. Transmissionsförluster beräknades för bassängen och maskinhallen. För bassängen användes mestadels observationsdata och kännedom hos personalen, medan maskinhallens isolering i huvudsak fick uppskattas efter byggår. Resultatet blev att värmepumpen med aktuellt körschema kunde täcka cirka 45 % av maskinhallens årliga uppvärmningsbehov. Av de 276 GJ som tillfördes genom kylning av ångkraftverket under ett år beräknades endast 2,7 % kunna utnyttjas till uppvärmning av maskinhallen, på grund av för lite isolering i bassängen. De största begränsningarna för högre täckning och större nyttjande av spillvärmen bedömdes vara placeringen i tid av kraftverkets körningar, och värmepumpens effekt. Om körningarna skulle förläggas i huvudsak till november–april och värmepumpen ersättas med en på 10 kW, skulle 74 % av värmebehovet kunna täckas och över 18 % av spillvärmen utnyttjas. Andra saker som förbättrad isolering i bassängen och större vattenvolym bedömdes också kunna förbättra bassängens kapacitet som energilager.HETA Education in Härnösand has a steam power plant for educational purposes which is cooled with water from a 329 m³ underground basin. The purpose of this thesis has been to examine how the basin with the waste heat can be used as seasonal thermal energy storage with an existing 7.8 kW heat pump in order to heat the machine room of their lab building. A spreadsheet was created in Microsoft Excel in order to carry out the calculations. As no measurement data was available, a simulated scenario was created based on temperature statistics and the operating schedule for the power plant from the year 2017. Transmission losses were calculated for the basin and the machine room. For the basin, mostly observational data and knowledge among the staff were used, while the insulation for the machine room mainly had to be estimated based on the construction year. The result was that the heat pump, with the current operating schedule, could cover around 45% of the yearly heating demand of the machine room. Of the 276 GJ that were added through cooling of the power plant during a year, according to calculations, only 2,7% could be used for heating the machine hall, due to lacking insulation in the basin. The greatest limitations for achieving a higher heating coverage and a greater usage of the waste heat were assessed to be the placement in time of the power plant runs, and the effect of the heat pump. If the runs would be placed mainly in November–April, and the heat pump replaced with a 10 kW one, around 74% of the heating demand could be covered and 18 % of the waste heat used. Other things, such as increased insulation in the basin and larger water volume were also assessed to be able to increase the capacity of the basin as heat storage.
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Mubarok, Mahdi. "Valorization of beech wood through development of innovative and environmentally friendly chemical modification treatments." Electronic Thesis or Diss., Université de Lorraine, 2019. http://www.theses.fr/2019LORR0141.
Full textAbstract:
Dans cette étude, l’amélioration des propriétés physiques et de sa durabilité aux agents de dégradation biologique du hêtre européen (Fagus sylvatica) a été réalisée au moyen de différents traitements. Les premiers types de traitements sont basés sur l'imprégnation de dérivés vinyliques de glycérol ou de polyglycérol en tant qu'additif suivi d’une étape de modification thermique réalisée dans un réacteur ouvert (OHT) ou fermé (HPS). Le deuxième type de traitement repose sur la poly-estérification in situ du sorbitol et de l'acide citrique à différentes concentrations et températures de durcissement en système ouvert. Diverses propriétés de durabilité physique, chimique, mécanique et biologique des bois modifiés ont été évaluées. Les résultats montrent que certains traitements peuvent améliorer de manière significative les propriétés de durabilité physique et biologique du bois contre les agents de pourriture blanche, brune et molle et surtout vis-à-vis de l’attaque des termites comparativement au bois non traité ou modifié thermiquement uniquementIn this study, improvement of physical and biological durability properties of European beech (Fagus sylvatica) has been performed through different bulking impregnation treatments. The first modification was based on the impregnation of vinylic derivatives of glycerol or polyglycerol as additive followed with different thermal modification conditions in the opened system (OHT) or in the closed system (HPS). The second modification was based on the in-situ polyesterification of sorbitol and citric acid at different concentrations and curing temperatures in the opened system. Various physical, chemical, mechanical, and biological durability properties of the modified woods were evaluated, including certain properties during modification. The results have disclosed that certain treatments can improve significantly physical and biological durability properties of wood against decay (white rot, brown rot, and soft rot fungi) and termites attacks in comparison to untreated wood or thermally modified woods
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WANG, RUI-LIAN, and 王瑞蓮. "Studies on the relationship between texture changes and chemical compositions during heating and pickling process ofmustard stem slices." Thesis, 1987. http://ndltd.ncl.edu.tw/handle/38333464512303097159.
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Yan, Haoheng. "From Mouse Mammary Tumor Model to New Therapeutic Method ---Mammary Tumor Development in Balb/c-Trp53+/- Mice and Magnetic Nanoparticle Induced Heating for Cancer Treatment." 2010. https://scholarworks.umass.edu/dissertations/AAI3409670.
Full textAbstract:
Mutation and loss of p53 function are common features among human breast cancers. We use BALB/c-Trp53+/- mice as a model to examine the sequence of events leading to mammary tumors. Mammary epithelium proliferation rates were similar in both BALB/c-Trp53+/- mice and wild type controls. Among the 28 mammary tumors collected from BALB/c- Trp53+/- mice, loss of heterozygosity for Trp53 was detected in more than 90% of invasive mammary tumors. Transplantation of Trp53+/- ductal hyperplasias indicated an association between loss of the wild type allele of Trp53 and progression to invasive carcinomas. Expression of biomarkers such as ERα, PR, Her2/Neu and activated Notch1 varied among the tumors suggesting that multiple oncogenic events collaborate with loss of p53 function. The majority of the tumors expressed both luminal and basal cytokeratins (59%). Gene expression analysis showed ligands and receptors of stem cell related pathways, such as Notch and Wnt, were increased in the tumors. These results indicate that mammary tumors in BALB/c Trp53+/- mice might initiate from bipotent mammary progenitor cells. Using magnetic nanoparticles for cancer thermotherapy. Alternating magnetic field (AMF) heating of magnetic nanomaterials provides a promising method for executing therapeutic thermal treatment for cancer patients. In order to explore the potential of magnetic nanoparticles (MNPs) for hyperthermia treatment, we synthesized iron oxide MNPs with various passivation by citric acid, folate, trimethylamine carboxylic acid, or albumin. The albumin passivated MNP (MNP-A) surpassed other MNPs, showing efficient heating with very low inherent cytotoxicity. Confocal microscopy located MNP-A (FITC tagged) accumulation in both cell nucleus and cytosol after 24hr incubation with HeLa cells. The quantity of cell bound MNP-A (including internalized and cell membrane bound MNP-A) was positively associated with MNP-A concentration and incubation time with cells. The MNP-A bound to cells was sufficient to increase the temperature in the cell pellet Δ7°C after 8min exposure to AMF. No significant temperature increase or cell death was detected in control groups. Our data demonstrate that MNP-A provides a selective tool for AMF-induced thermal treatment, as well as useful dosing information for future preclinical animal studies.
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Ali, Mir Muddassir. "Optimized Control Of Steam Heating Coils." Thesis, 2011. http://hdl.handle.net/1969.1/ETD-TAMU-2011-12-10283.
Full textAbstract:
Steam has been widely used as the source of heating in commercial buildings and industries throughout the twentieth century. Even though contemporary designers have moved to hot water as the primary choice for heating, a large number of facilities still use steam for heating. Medical campuses with on-site steam generation and extensive distribution systems often serve a number of buildings designed prior to the mid-1980s. The steam is typically used for preheat as its high thermal content helps in heating the air faster and prevents coils from freezing in locations with extreme weather conditions during winter.
The present work provides a comprehensive description of the various types of steam heating systems, steam coils, and valves to facilitate the engineer's understanding of these steam systems.
A large percentage of the steam coils used in buildings are provided with medium pressure steam. Veterans Integrated Service Network and Army Medical Command Medical Facilities are examples which use medium pressure steam for heating. The current design manual for these medical facilities recommends steam at 30psig be provided to these coils. In certain cases although the steam heating coil is designed for a 5psig steam pressure, it is observed that higher pressure steam is supplied at the coil. A higher steam pressure may lead to excessive heating, system inefficiency due to increased heat loss, simultaneous heating and cooling, and increased maintenance cost.
Field experiments were conducted to evaluate the effect of lowering steam pressure on the system performance. A 16% reduction in temperature rise across the coil was found when the steam pressure in the coil was reduced from 15psig to 5psig. The rise in temperature with lower pressure steam was sufficient to prevent coil freeze-up even in the most severe weather conditions. Additional benefits of reduced steam pressure are reduced flash steam losses (flash steam is vapor or secondary steam formed when hot condensate from the coil is discharged into a lower pressure area, i.e., the condensate return line) and radiation losses, increased flow of air through the coil thereby reducing air stratification and reduced energy losses in the event of actuator failure.
The work also involved evaluating the existing control strategies for the steam heating system. New control strategies were developed and tested to address the short comings of existing sequences. Improved temperature control and occupant comfort; elimination of valve hunting and reduced energy consumption were benefits realized by implementing these measures.
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Ostermann, Rebecca Ann. "Direct steam injection heating of liquid food products." 2005. http://digital.library.okstate.edu/etd/umi-okstate-1591.pdf.
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Yu-LinSu and 蘇育霖. "Numerical simulation applied to methanol steam reforming using catalyst heating." Thesis, 2013. http://ndltd.ncl.edu.tw/handle/36767885172109206007.
Full textAbstract:
碩士國立成功大學
系統及船舶機電工程學系碩博士班
101
This study builds numerical simulation of a three-dimensional methanol steam reforming reactor. The study includes three parts, the first part is to simulate the methanol steam reforming reaction of fixed wall temperature without spray, and then to the results with the literature and the experimental data of our research team to confirm the accuracy of this simulation. The second part is to build the methanol steam reforming reaction of fixed wall temperature with spray model, and then to compare the results with experimental data to verify this model. The third part is to simulate the temperature distribution of the heating shell tube of experiments. Combining experience of simulation in the first part and the second part builds the reforming reactor model with the shell tube and heating catalyst. In addition, the temperature distributions are investigated at different O2/C ratio. The simulation results of the first part show that the concentration distribution of each component matches with the literature’s trend. In the first part, the result of between simulation and experiment of the hydrogen concentration is less than 1 %, and the methanol conversion rate at S/C ratio is greater than 1 can up to 99 %. In the second part, the result of between simulation and experiment shows that the methanol conversion rate of simulated is higher than experimental about 10 %. In the third part, the temperature first rises and then drops with raising the O2/C ratio using a gaseous methanol as fuel in the heating shell tube.
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Gway, Kuo-Hwa, and 桂國華. "Transient Mixed Convection of A Back Step with Periodic Heating Wall." Thesis, 1993. http://ndltd.ncl.edu.tw/handle/05571689597312847444.
Full textAbstract:
碩士國立成功大學
機械工程研究所
81
In the thesis, the unsteady mixed convection heat transfer of a backward-facing step subjected to a perio- dic heating wall is studied numerically. The governing equations for conservation of mass,momentum and heat are recasting into streaming- function, vorticity transport and energy equation. By introducing some paper dimensio- nless variables, the governing equations are then trans- formed into dimensionless forms. The velocity distribut- ion at inlet is assumed a fully-developed, parabolic pr- ofiled. The upper wall opposed to the step is assumed to be adiabatic and lower wall together with step are spec- ified a sinusoidally time-varying wall temperature with an non-zero mean temperature. Base on control volume approach, the finite diff- erence solution of the above non-dimensional governing equations are sought. Vorticity transport equation and energy equation are solved by using A.D.I.scheme. S.O.R. method is used to solve the stream function equation. In the present numerical study, the Prandtl numbers are gi- ven as 0.7,7,and 0.03 which are presented for air, water and liquid metal respectively. The amplitude and freque- ncy of the time- varying wall temperature are specified to be constant values of 0.4 and 0.01 respective. The results show that the fluid with smaller Pra- ndtl number is more sensitive to the time-varying wall temperature boundary conditions. In the Pr=0.03 case,the quasi-steady temperature distribution at the cross sect- ion of reattachment point is found to behave as Stoke's second problem, i.e. flow above an oscillating infinite plate. For the vertical flow case, it is found that the reattachment length is shorter than the horizontal flow case and the streamlines are closed to the heating wall, it means the fluid near the heating wall is flow faster. Finally, according to all the running cases, it is found that the oscillating heated wall does not affect the fl- ow field, but the local Nusselt numbers are affectd sig- nificantly.
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Hsu, Wei-Kai, and 徐尉凱. "The Feasibility Study of Applying Steam Curing and Microwave Heating Technology for Fresh Concrete." Thesis, 2002. http://ndltd.ncl.edu.tw/handle/34502026044499014324.
Full textAbstract:
碩士朝陽科技大學
營建工程系碩士班
90
ABSTRACT In this study, cement sand paste and common concrete with or without slag, fly ash and silica fume were used to investigate some accelerated curing on the strength and permeability of concrete. In order to evaluate some rapid testing procedure which could run a series of tests within one day to attain an estimate of the 28-day strength of the concrete, specimens with microwave heat curing in different hydration stages were tested on compressive strength, ultrasonic, water adsorption and chloride electrical permeability. The steam curing and microwave heating techniques provide the advantage of quick and uniform heating for curing of cementitious materials. The study on cement sand paste and common concrete with or without slag, fly ash and silica fume was been used the above tests and to be expected more precise relation between the accelerated strength and that obtained after 7 or 28 days normal curing. Some specimens with specific curing age were tested on X-Ray microanalysis. The initial result was found that the accelerated curing on fresh sand paste or concrete samples with or without pozzolanic materials which combines steam curing and microwave heat curing could increase strength successfully within one day. Some accelerated curing samples can reach 7-day compressive strength and the others can reach 28-day compressive strength. It was found that the 28-day chloride electrical permeability of the accelerated curing samples reduce greatly when curing them in water after the accelerated curing. The samples with slag make a contribution to the denseness of microstructure and reduce the chloride electrical permeability.
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Chen, Hung-Wen, and 陳泓文. "Study on Heat and Mass Transfer in Superheated Steam Heating Process of Starchy Food." Thesis, 2013. http://ndltd.ncl.edu.tw/handle/81307262579385561396.
Full textAbstract:
碩士國立臺灣大學
生物產業機電工程學研究所
101
Superheated steam means the steam temperature is higher than the boiling point under the ambient pressure. The usage of superheated steam in food process industry provides some benefits, like high energy efficiency and f maintaining better food quality. Superheated steaming has been applied in food treatment for decades, the heat and mass transfer mechanism of superheated steaming in porous starchy food has not been fully explored. In this study, we developed the mathematical models which coupled with energy, water and vapor transport during superheated steaming process. Experiments of reheating a porous starchy food, the steamed buns in our case, was operated to observe the temperature, humidity and weight change under superheated steaming. The mathematical models involved the governing equations of heat and mass transfer with water condensation and evaporation in the porous starchy matrix and the boundary conditions was considered of superheated steaming environment. We compared the experimental data with the simulation results which solved by commercial finite element software (COMSOL Multiphysics) to verify the correctness of this models. It showed a good agreement between the experimental and simulation results in temperature and water content change during the process. The effects of water condensation and evaporation were significant during the heating process; the vapor transported through the porous media can contribute different temperature increasing profile from other non-porous material. The models constructed in this study can provide a fundamental concept of superheated steam treatment in porous starchy food for the future study in more complicated food process.
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He, Juan. "Flavor comparison of ultra high temperature processed milk heated by Ohmic heating and conventional methods." Thesis, 2012. http://hdl.handle.net/1957/28661.
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Ultra high temperature (UHT) processing can extend shelf life of milk to several months without refrigeration, which is more convenient and energy saving than pasteurized milk. However, the poor acceptance caused by "cooked" flavors limits its marketing growth, especially in United States. Ohmic heating, which has a more uniform and rapid heating than conventional UHT process, may minimized the flavor change during the thermal treatment. Flavor composition between Ohmic heated UHT milk and other traditionally processed UHT milk (direct steam injection and indirect plate heating) during 36 weeks storage were investigated in this study. A total of 20 volatile compounds were analyzed based on their importance to UHT milk as well as their representation to different chemical classes including sulfur-containing compounds, ketones, lactones, aldehydes and others. Dimethyl sulfide (DMS) and methyl ketones were significant different among three types of UHT heated milk. δ-lactones showed higher amount in Ohmic heating after stored for four weeks, which might generate creamy, fruity intermediate aroma. Other compounds showed no significant difference among three heating processes. Aroma recombination test revealed that the overall aroma of the ultra pasteurized (UP) milk could be mimicked by recombining 15 important reference odorants in the same concentrations as they occurred in the UHT milk using commercial pasteurized milk as the matrix.Graduation date: 2012
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Van, Niekerk Steven Cronier. "Optimisation criteria of a Rankine steam cycle powered by thorium HTR / Steven Cronier van Niekerk." Thesis, 2014. http://hdl.handle.net/10394/12209.
Full textAbstract:
HOLCIM has various cement production plants across India. These plants struggle to
produce the projected amount of cement due to electricity shortages. Although coal is
abundant in India, the production thereof is in short supply.
It is proposed that a thorium HTR (100 MWt) combined with a PCU (Rankine cycle) be
constructed to supply a cement production plant with the required energy. The Portland
cement production process is investigated and it is found that process heat integration is not
feasible.
The problem is that for the feasibility of this IPP to be assessed, a Rankine cycle needs to be
adapted and optimised to suit the limitations and requirements of a 100 MWt thorium HTR.
Advantages of the small thorium HTR (100 MWt) include: on-site construction; a naturally
safe design and low energy production costs. The reactor delivers high temperature helium
(750°C) at a mass flow of 38.55 kg/s. Helium re-en ters the reactor core at 250°C.
Since the location of the cement production plant is unknown, both wet and dry cooling tower
options are investigated. An overall average ambient temperature of India is used as input
for the cooling tower calculations.
EES software is used to construct a simulation model with the capability of optimising the
Rankine cycle for maximum efficiency while accommodating various out of the norm input
parameters. Various limitations are enforced by the simulation model.
Various cycle configurations are optimised (EES) and weighed against each other. The
accuracy of the EES simulation model is verified using FlowNex while the optimised cycle
results are verified using Excel’s X-Steam macro.
It is recommended that a wet cooling tower is implemented if possible. The 85% effective
heat exchanger delivers the techno-economically optimum Rankine cycle configuration. For
this combination of cooling tower and heat exchanger, it is recommended that the cycle
configuration consists of one de-aerator and two closed feed heaters (one specified).
After the Rankine cycle (PCU) has been designed and optimised, it is evident that the small
thorium HTR (100 MWt) can supply the HOLCIM plant with the required energy. The optimum cycle configuration, as recommended, operates with a cycle efficiency of 42.4%
while producing 39.867 MWe. A minimum of 10 MWe can be sold to the Indian distribution
network at all times, thus generating revenue.MIng (Mechanical Engineering), North-West University, Potchefstroom Campus, 2014
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"Effect of pretreatment on the breakdown of lignocellulosic matrix in barley straw as feedstock for biofuel production." Thesis, 2014. http://hdl.handle.net/10388/ETD-2014-10-1609.
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Lignocellulosic biomass is composed of cellulose, hemicellulose, lignin and extraneous compounds (waxes, fats, gums, starches, alkaloids, resins, tannins, essential oils, silica, carbonates, oxalates, etc). The sugars within the complex carbohydrates (cellulose and hemicellulose) can be accessed for cellulosic bioethanol production through ethanologenic microorganisms. However, the composite nature of lignocellulosic biomass, particularly the lignin portion, presents resistance and recalcitrance to biological and chemical degradation during enzymatic hydrolysis/saccharification and the subsequent fermentation process. This leads to a very low conversion rate, which makes the process uneconomically feasible. Thus, biomass structure requires initial breakdown of the lignocellulosic matrix.
In this study, two types of biomass pretreatment were applied on barley straw grind: radio-frequency (RF)-based dielectric heating technique using alkaline (NaOH) solution as a catalyst and steam explosion pretreatment at low severity factor. The pretreatment was applied on barley straw which was ground in hammer mill with a screen size of 1.6 mm, so as to enhance its accessibility and digestibility by enzymatic reaction during hydrolysis. Three levels of temperature (70, 80, and 90oC), five levels of ratio of biomass to 1% NaOH solution (1:4, 1:5, 1:6, 1:7, & 1:8), 1 h soaking time, and 20 min residence time were used for the radio frequency pretreatment. The following process and material variables were used for the steam explosion pretreatment: temperature (140-180oC), retention time (5-10 min), and 8-50% moisture content (w.b). The effect of both pretreatments was assessed through chemical composition analysis and densification of the pretreated and non-pretreated biomass samples. Results of this investigation show that lignocellulosic biomass absorbed more NaOH than water, because of the hydrophobic nature of lignin, which acts as an external crosslink binder on the biomass matrix and shields the hydrophilic structural carbohydrates (cellulose and hemicellulose). It was observed in the RF pretreatment that the use of NaOH solution and the ratio of biomass to NaOH solution played a major role, while temperature played a lesser role in the breakdown of the lignified matrix, as well as in the production of pellets with good physical quality. The heat provided by the RF is required to assist the alkaline solution in the deconstruction and disaggregation of lignocellulosic biomass matrix. The disruption and deconstruction of the lignified matrix is also associated with the dipole interaction, flip flop rotation, and friction generated between the electromagnetic charges from the RF and the ions and molecules from the NaOH solution and the biomass. The preserved cellulose from the raw sample (non-treated) was higher than that from the RF alkaline pretreated samples because of the initial degradation of the sugars during the pretreatment process. The same observation applies to hemicellulose. This implies that there is a trade-off between the breakdown of the biomass matrix/creating pores in the lignin and enhancing the accessibility and digestibility of the cellulose and hemicellulose. The use of dilute NaOH solution in biomass pretreatment showed that the higher the NaOH concentration, the lower was the acid insoluble lignin and the higher was the solubilized lignin moieties. The ratio of 1:6 at the four temperatures studied was determined to be the optimal. Based on the obtained data, it is predicted that this pretreatment will decrease the required amount and cost of enzymes by up to 64% compared to using non-treated biomass. However, the use of NaOH led to an increase in the ash content of biomass. The ash content increased with the decreasing ratio of biomass to NaOH solution. This problem of increased ash content can be addressed by washing the pretreated samples. RF assisted-alkaline pretreatment technique represents an easy to set-up and potentially affordable route for the bio-fuel industry, but this requires further energy analysis and economic validation, so as to investigate the significant high energy consumption during the RF-assisted alkaline pretreatment heating process.
Data showed that in the steam explosion (SE) pretreatment, considerable thermal degradation of the energy potentials (cellulose and hemicellulose) with increasing acid soluble and insoluble lignin content occurred. The high degradation of the hemicellulose can be accounted for by its amorphous nature which is easily disrupted by external influences unlike the well-arranged crystalline cellulose. It is predicted that this pretreatment will decrease the required amount and cost of enzymes by up to 33% compared to using non-treated biomass.The carbon content of the solid SE product increased at higher temperature and longer residence time, while the hydrogen and oxygen content decreased.
The RF alkaline and SE treatment combinations that resulted to optimum yield of cellulose and hemicellulose were selected and then enzymatically digested with a combined mixture of cellulase and β-glucosidase enzymes at 50oC for 96 h on a shaking incubator at 250 rev/min. The glucose in the hydrolyzed samples was subsequently quantified. The results obtained confirmed the effectiveness of the pretreatment processes. The average available percentage glucose yield that was released during the enzymatic hydrolysis for bioethanol production ranged from 78-96% for RF-alkaline pretreated and 30-50% for the SE pretreated barley straw depending on the treatment combination. While the non-treated sample has available average percentage glucose yield of just below 12%.
The effects of both pretreatment methods (RF and SE) were further evaluated by pelletizing the pretreated and non-pretreated barley straw samples in a single pelleting unit. The physical characteristics (pellet density, tensile strength, durability rating, and dimensional stability) of the pellets were determined. The lower was the biomass:NaOH solution ratio, the better was the quality of the produced pellets. Washing of the RF-alkaline pretreated samples resulted in pellets with low quality. A biomass:NaOH solution ratio of 1:8 at the three levels of temperature (70, 80, and 90oC) studied are the RF optimum pretreatment conditions. The higher heating value (HHV) and the physical characteristics of the produced pellets increased with increasing temperature and residence time. The steam exploded samples pretreated at higher temperatures (180ºC) and retention time of 10 min resulted into pellets with good physical qualities.
Fourier transform infrared-photoacoustic spectroscopy (FTIR-PAS) was further applied on the RF alkaline and SE samples in light of the need for rapid and easy quantification of biomass chemical components (cellulose, hemicellulose, and lignin). The results obtained show that the FTIR-PAS spectra can be rapidly used for the analysis and identification of the chemical composition of biofuel feedstock. Predictive models were developed for each of the biomass components in estimating their respective percentage chemical compositions.
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Hedderman, Simon Peter. "Developments for a Swept Wing Airfoil to Study the Effects of Step and Gap Excrescences on Boundary Layer Transition." Thesis, 2013. http://hdl.handle.net/1969.1/149269.
Full textAbstract:
Skin friction drag reduction is one of the most promising paths in the investigation of the reduction of aircraft fuel burn. 40 – 50% of overall drag comes from the surfaces of the wings and stabilizers. Natural laminar flow airfoils can extend the region of laminar flow and reduce skin friction drag. However, real-world aircraft wings do not have perfectly smooth surfaces, and therefore the tolerances for step and gap excrescences on these airfoils must be investigated. Previous work has focused on excrescences on flat plates, and only recently included pressure gradient effects.
A new three-dimensional swept wing airfoil with an actuated leading edge (SWIFTER) has been constructed, and will extend the body of knowledge of step and gap excrescences to a more real-world configuration and higher Reynolds numbers. An integrated control system for the leading edge actuation system is proposed, including both interface hardware and control code. A heating system for the test surface is also discussed, and the controller hardware, sensors, and code specified. For wind tunnel testing, a proposed set of wall liners are developed from zero-lift condition streamlines and divided into parts suitable for manufacturing, assembly, and installation. Finally, preliminary wind tunnel step excrescence tests using an existing swept-wing model and applique step material were conducted, and the results are discussed with relevance to testing on the new model.
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Lindén, Magnusson Josephine. "Ångdrift av värmepumpar i Solnaverket : En teknisk och ekonomisk studie över konvertering från eldrift till mekanisk ångdrift." Thesis, 2020. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-415326.
Full textAbstract:
This master thesis has examined how two of the heat pumps at Norrenergi, Solnaverket, can be converted to steam driven heat pumps. The heat pumps are driven by electrical motors today and this thesis has investigated the technical and economical aspects of replacing them with steam turbines and also installing a pellet boiler. The purpose with this project is to lower the costs for the heat pumps which varies with the electricity price, where the electricity taxes represent about 40-60 % of the total electricity cost. In addition, Norrenergi is one of the largest electricity consumers in Stockholm. This, combined with the prevailing capacity shortage in Stockholm makes it important to examine another alternative than electricity for the heat pumps. Capacity shortage means that electricity can't be transmitted into the city during periods with high electricity demand. The results of this master thesis show that the costs reduces on a system level when two steam driven heat pumps are installed compared to the electrity driven heat pumps. All district heating plants in Stockholm, including Söderenergi's, Norrenergi's and Stockholm Exergi's plants, have been involved while examining the costs in this study. Despite the cost reduction the investment calculation shows that the investment is not profitable for a low or average electrity price. For a high electricity price the investment seems to be profitable, but this is not considered enough for the investment to be recommend since future electricty prices are hard to predict. On the other hand there might be other aspects than economical to invest in this type of district heating plant, for example from a sustainability perspective.Norrenergi är ett fjärrvärme- och fjärrkylabolag i Stockholm som bland annat producerar värme via energiåtervinning i en VP-anläggning i Solnaverket. Värmepumparna har en total värmeeffekt på 100 MW och drivs av elektricitet samt spillvatten från Bromma reningsverk. Kostnaden för att producera fjärrvärme via värmepumpar varierar med elpriset där en betydande faktor är elskatten. Elskatten utgör ungefär 40–60 % av den totala elkostnaden för VP-anläggningen i Solnaverket. Utöver de höga kostnaderna för att driva VP-anläggningen råder en så kallad kapacitetsbrist i Stockholm vilket bland annat grundar sig i att staden växt i en snabbare takt än utbyggnaden av stamnätet. På grund av ovan nämnda orsaker är det intressant att undersöka alternativa lösningar för hur den eldrivna VP-anläggningen kan producera fjärrvärme, dels för att minska kostnader för elektricitet men också för att bidra till en samhällsnytta genom att minska effektuttaget på elnätet. Detta examensarbete ämnar därför undersöka hur två av värmepumparna i Solnaverket kan omvandlas från eldrift till mekanisk ångdrift via ångturbiner, där ångturbinerna i sin tur drivs av ånga från en pelletspanna. Därtill undersöks systemdriftsnyttan, där även Stockholm Exergis och Söderenergis anläggningar beaktas, samt lönsamheten för att konvertera två av värmepumparna till ångdrift. Resultatet visar att systemdriftsnyttan är positiv oavsett elprisprofil vilket beror på att kostnaderna på systemnivå minskar när ångdriven VP-anläggning implementeras i Solnaverket. Trots den positiva systemdriftsnyttan visar dock investeringskalkylen att denna investering endast är lönsam vid ett högt elpris. Det beror bland annat på att den positiva systemdriftsnyttan inte är tillräckligt hög (vid låg och medelelpris) för att uppnå ett tillräckligt högt nuvärde med given kalkylränta och ekonomisk livslängd, i jämförelse med grundinvesteringskostnaderna. Den låga lönsamheten beror dessutom på att Stockholm Exergi ska bygga ett nytt avfallskraftvärmeverk i Lövsta som har billigare produktionskostnader än den ångdrivna VP-anläggningen. Det är svårt att förutspå elprisets utveckling framöver och variationerna i elpris under året förväntas öka, därför är det rekommenderat att denna investeringen inte genomförs eftersom den beror så pass mycket av elpriset. Det kan dock finnas andra aspekter än ekonomiska i att investera i en ångdriven VP-anläggning. Till exempel ur ett hållbarhetsperspektiv då belastningen på elnätet minskar när de eldrivna VP:arna konverteras till ångdrift.
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Lashgari, Hamid Reza. "Development of a four-phase thermal-chemical reservoir simulator for heavy oil." Thesis, 2014. http://hdl.handle.net/2152/28477.
Full textAbstract:
Thermal and chemical recovery processes are important EOR methods used often by the oil and gas industry to improve recovery of heavy oil and high viscous oil reservoirs. Knowledge of underlying mechanisms and their modeling in numerical simulation are crucial for a comprehensive study as well as for an evaluation of field treatment. EOS-compositional, thermal, and blackoil reservoir simulators can handle gas (or steam)/oil/water equilibrium for a compressible multiphase flow. Also, a few three-phase chemical flooding reservoir simulators that have been recently developed can model the oil/water/microemulsion equilibrium state. However, an accurate phase behavior and fluid flow formulations are absent in the literature for the thermal chemical processes to capture four-phase equilibrium. On the other hand, numerical simulation of such four-phase model with complex phase behavior in the equilibrium condition between coexisting phases (oil/water/microemulsion/gas or steam) is challenging. Inter-phase mass transfer between coexisting phases and adsorption of components on rock should properly be modeled at the different pressure and temperature to conserve volume balance (e.g. vaporization), mass balance (e.g. condensation), and energy balance (e.g. latent heat). Therefore, efforts to study and understand the performance of these EOR processes using numerical simulation treatments are quite necessary and of utmost importance in the petroleum industry. This research focuses on the development of a robust four-phase reservoir simulator with coupled phase behaviors and modeling of different mechanisms pertaining to thermal and chemical recovery methods. Development and implementation of a four-phase thermal-chemical reservoir simulator is quite important in the study as well as the evaluation of an individual or hybrid EOR methods. In this dissertation, a mathematical formulation of multi (pseudo) component, four-phase fluid flow in porous media is developed for mass conservation equation. Subsequently, a new volume balance equation is obtained for pressure of compressible real mixtures. Hence, the pressure equation is derived by extending a black oil model to a pseudo-compositional model for a wide range of components (water, oil, surfactant, polymer, anion, cation, alcohol, and gas). Mass balance equations are then solved for each component in order to compute volumetric concentrations. In this formulation, we consider interphase mass transfer between oil and gas (steam and water) as well as microemulsion and gas (microemulsion and steam). These formulations are derived at reservoir conditions. These new formulations are a set of coupled, nonlinear partial differential equations. The equations are approximated by finite difference methods implemented in a chemical flooding reservoir simulator (UTCHEM), which was a three-phase slightly compressible simulator, using an implicit pressure and an explicit concentration method. In our flow model, a comprehensive phase behavior is required for considering interphase mass transfer and phase tracking. Therefore, a four-phase behavior model is developed for gas (or steam)/ oil/water /microemulsion coexisting at equilibrium. This model represents coupling of the solution gas or steam table methods with Hand’s rule. Hand’s rule is used to capture the equilibrium between surfactant, oil, and water components as a function of salinity and concentrations for oil/water/microemulsion phases. Therefore, interphase mass transfer between gas/oil or steam/water in the presence of the microemulsion phase and the equilibrium between phases are calculated accurately. In this research, the conservation of energy equation is derived from the first law of thermodynamics based on a few assumptions and simplifications for a four-phase fluid flow model. This energy balance equation considers latent heat effect in solving for temperature due to phase change between water and steam. Accordingly, this equation is linearized and then a sequential implicit scheme is used for calculation of temperature. We also implemented the electrical Joule-heating process, where a heavy oil reservoir is heated in-situ by dissipation of electrical energy to reduce the viscosity of oil. In order to model the electrical Joule-heating in the presence of a four-phase fluid flow, Maxwell classical electromagnetism equations are used in this development. The equations are simplified and assumed for low frequency electric field to obtain the conservation of electrical current equation and the Ohm's law. The conservation of electrical current and the Ohm's law are implemented using a finite difference method in a four-phase chemical flooding reservoir simulator (UTCHEM). The Joule heating rate due to dissipation of electrical energy is calculated and added to the energy equation as a source term. Finally, we applied the developed model for solving different case studies. Our simulation results reveal that our models can accurately and successfully model the hybrid thermal chemical processes in comparison to existing models and simulators.text
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Li, Bo. "Energy saving opportunities in residential buildings: insights from technological and building energy code perspectives." Thesis, 2020. http://hdl.handle.net/1828/12135.
Full textAbstract:
The residential building sector plays an important role in combating climate change in Canada. Many energy efficiency solutions along with new building energy standards have been implemented to improve building energy performance. However, their effects on energy saving and GHG emissions reduction vary due to the complexity of the building systems and the variability of their operational conditions. This work quantifies such variability in both energy efficiency devices and building energy standards implementation, respectively.
The first study in this dissertation assesses the energy savings from sensible heat recovery in a residential apartment suite in various locations across Canada. A series of detailed building energy performance models are developed in TRNSYS. The HVAC system’s annual energy consumption is simulated and the results are compared with and without HRV for each climate zone. The results show the heating energy savings of employing the HRV vary from 17 to 34% depending on the winter climatic conditions; while, the building cooling energy use can be increased due to the undesired thermal recovery occurring in the HRV during the cooling season.
The second study investigates the free cooling potential of outside air in various Canadian cities. A series of thermal models developed using BEopt 2.8 for a hypothetical single-family house with various window-to-wall ratios and building aspect ratios simulates hourly building cooling load profiles. The free cooling potential is analyzed by comparing the maximum available and the actual usable free cooling for various building features and different climates. The results indicate that, although free cooling is widely available in most areas of Canada during the summer and shoulder seasons, only 17-42% of such free cooling is usable without the use of thermal storage.
The last study examines the effects of two building energy standards - the BC Step Code and the Passive House criteria - on reductions in residential household space heating GHG emissions under different enforcement scenarios. The space heating energy and the GHG emissions are estimated using the forecast growth of single detached households for the period from 2020 to 2032. The results show that the space heating GHG emissions can be reduced by 77% and 89%, respectively if the BC Step Code or the Passive House criteria is implemented in Canada. It is also found the impacts of energy code on GHG emission mitigation are less significant in regions where the carbon intensity of the dominant heating fuels is low.Graduate