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Fox, Charles Daniel. "A BASIC UNDERSTANDING OF RAPID MOLD SURFACE HEATING VIA LASER ENERGY." Wright State University / OhioLINK, 2012. http://rave.ohiolink.edu/etdc/view?acc_num=wright1341332102.
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Anslin, Mathias, and Alexander Bölke. "Sliding bearings in heavy duty engines : A bearing wear comparative study." Thesis, KTH, Maskinkonstruktion (Inst.), 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-209584.
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Start-stop systems are widely used in the car industry today but have not yet been fully implemented in the heavy-duty vehicle industry. The greater loads arising in the engines leads to excessive wear of the hydrodynamic bearings during starts and stops which has a distinct impact on the machine´s lifetime performance and reliability. This master thesis involves a comparative study of how different surface topographies of a shaft affects hydrodynamic bearing wear during start and stop conditions. The objective was to see if one can extend the bearing lifetime by doing minor changes to the shaft surface. This has been done by redesigning an existing start-stop test rig, increasing its operating system oil temperature to 90°C to provide a more accurate description of the bearing environment, to be able to conduct a series of start-stop cycling experiments. Upon examination of the experiment results, it becomes clear that a more polished surface of the shaft does reduce bearing wear significantly during starts and stops. It was also noticed that a more polished shaft surface does reach full-film lubrication at a lower rotational speed of the shaft, separating the shaft and the bearing surfaces.Start-stoppsystem används idag i stor utsträckning inom bilindustrin men har ännu inte blivit implementerat fullt ut i den tunga fordonsindustrin. De större belastningarna som uppstår i motorn leder till överdrivet slitage på de hydrodynamiska glidlagren under start och stopp och har en tydlig inverkan på maskinens livslängd och pålitlighet. Detta examensarbete har innefattat en jämförande studie om hur olika axelytor påverkar nötningen av hydrodynamiska glidlager vid start och stoppförhållanden. Målet var att se ifall man kan lyckas förlänga lagrets livslängd genom att genomföra mindre förändringar av axelytan. Detta har utförts genom att omkonstruera en befintlig start-stopprigg, ökat oljesystemets driftstemperatur till 90°C för att ge en mer exakt beskrivning av den riktiga lagermiljön, för att sedan ha utfört en serie start och stopp experiment. Resultaten från experimenten visade tydligt att en mer polerad axelyta minskar lagerslitningen avsevärt under start och stopp. Det noterades också att en mer polerad axelyta ger fullfilmssörjning vid en lägre axelrotationshastighet, varvid axeln och lagerytorna separeras.
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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.
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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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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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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.
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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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Andersen, Michael Louis. "Roughening of surfaces under intense and rapid heating." Diss., Restricted to subscribing institutions, 2008. http://proquest.umi.com/pqdweb?did=1709043171&sid=5&Fmt=2&clientId=1564&RQT=309&VName=PQD.
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Martin, Guillaume. "District Heating Networks Design." Thesis, KTH, Skolan för industriell teknik och management (ITM), 2019. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-264257.
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District heating networks are a solution to decrease the amount of CO2 emission in the atmosphere and a mean to increase the share of renewable energy in the energy mix. This degree project, conducted at Engie Réseaux, investigates the best options to design them. The challenges and the constraints of their design will be developed and the tools created to achieve it will be presented. This thesis exposes the major climatologic, economic, and energetic parameters to take into account when designing a network and shows the methodology used in these three fields.Fjärrvärmenät är en lösning för att minska mängden koldioxidutsläpp i atmosfären och ett medel för att öka andelen förnybar energi i energimixen. Detta examensarbete, utfört på Engie Réseaux, undersöker de bästa alternativen för att designa dem. Svårigheterna och begränsningarna i deras utformning kommer att utvecklas och de verktyg som skapats för att uppnå det kommer att presenteras. Denna avhandling visar de viktigaste klimatologiska, ekonomiska och energiska parametrarna att ta hänsyn till vid utformning av ett nätverk och visar den använda metodiken.
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Martín, Segura Guillermo. "Induction heating converter's design, control and modeling applied to continuous wire heating." Doctoral thesis, Universitat Politècnica de Catalunya, 2012. http://hdl.handle.net/10803/83346.
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Induction heating is a heating method for electrically conductive materials that takes advantage of the heat generated by the Eddy currents originated by means of a varying magnetic field. Since Michael Faraday discovered electromagnetic induction in 1831, this phenomena has been widely studied in many applications like transformers, motors or generators' design. At the turn of the 20th century, induction started to be studied as a heating method, leading to the construction of the first industrial induction melting equipment by the Electric Furnace Company in 1927.
At first, the varying magnetic fields were obtained with spark-gap generators, vacuum-tube generators and low frequency motor-generator sets. With the emergence of reliable semiconductors in the late 1960's, motor-generators were replaced by solid-state converters for low frequency applications.
With regard to the characterization of the inductor-workpiece system, the first models used to understand the load's behavior were based on analytical methods. These methods were useful to analyze the overall behavior of the load, but they were not accurate enough for a precise analysis and were limited to simple geometries. With the emergence of computers, numerical methods experienced a tremendous growth in the 1990's and started to be applied in the induction heating field. Nowadays, the development of commercial softwares that allow this type of analysis have started to make the use of numerical methods popular among research centers and enterprises. This type of softwares allow a great variety of complex analysis with high precision, consequently diminishing the trial and error process.
The research realized in last decades, the increase in the utilization of numerical modeling and the appearance and improvement of semiconductor devices, with their corresponding cost reduction, have caused the spread of induction heating in many fields. Induction heating equipments can be found in many applications, since domestic cookers to high-power aluminum melting furnaces or automotive sealing equipments, and are becoming more and more popular thanks to their easy control, quick heating and the energy savings obtained.
The present thesis focuses on the application of induction heating to wire heating. The wire heating is a continuous heating method in which the wire is continuously feeding the heating inductor. This heating method allows high production rates with reduced space requirements and is usually found in medium to high power industrial processes working 24 hours per day.
The first chapters of this study introduce the induction heating phenomena, its modeling and the converters and tanks used. Afterwards, a multichannel converter for high-power and high-frequency applications is designed and implemented with the aim of providing modularity to the converter and reduce the designing time, the production cost and its maintenance. Moreover, this type of structure provides reliability to the system and enables low repairing times, which is an extremely interesting feature for 24 hours processes.
Additionally, a software phase-locked loop for induction heating applications is designed and implemented to prove its flexibility and reliability. This type of control allows the use of the same hardware for different applications, which is attractive for the case of industrial applications. This phase-locked loop is afterwards used to design and implement a load-adaptative control that varies the references to have soft-switching according to load's variation, improving converter's performance.
Finally, the modeling of a continuous induction wire hardening system is realized, solving the difficulty of considering the mutual influence between the thermal, electromagnetic and electric parameters. In this thesis, a continuous process is modeled and tested using numerical methods and considering converter's operation and influence in the process.
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Cowley, Adam M. "Hydrodynamic and Thermal Effects of Sub-critical Heating on Superhydrophobic Surfaces and Microchannels." BYU ScholarsArchive, 2017. https://scholarsarchive.byu.edu/etd/6572.
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This dissertation focuses on the effects of heating on superhydrophobic (SHPo) surfaces. The work is divided into two main categories: heat transfer without mass transfer and heat transfer in conjunction with mass transfer. Numerical methods are used to explore the prior while experimental methods are utilized for the latter. The numerical work explores convective heat transfer in SHPo parallel plate microchannels and is separated into two stand-alone chapters that have been published archivally. The first considers surfaces with a rib/cavity structure and the second considers surfaces patterned with a square lattice of square posts. Laminar, fully developed, steady flow with constant fluid properties is considered where the tops of the ribs and posts are maintained at a constant heat flux boundary condition and the gas/liquid interfaces are assumed to be adiabatic. For both surface configurations the overall convective heat transfer is reduced. Results are presented in the form of average Nusselt number as well as apparent temperature jump length (thermal slip length). The heat transfer reduction is magnified by increasing cavity fraction, decreasing Peclet number, and decreasing channel size relative to the micro-structure spacing. Axial fluid conduction is found to be substantial at high Peclet numbers where it is classically neglected. The parameter regimes where prior analytical works found in the literature are valid are delineated. The experimental work is divided into two stand-alone chapters with one considering channel flow and the other a pool scenario. The channel work considers high aspect ratio microchannels with one heated SHPo wall. If water saturated with dissolved air is used, the air-filled cavities of SHPo surfaces act as nucleation sites for mass transfer. As the water heats it becomes supersaturated and air can effervesce onto the SHPo surface forming bubbles that align to the underlying micro-structure if the cavities are comprised of closed cells. The large bubbles increase drag in the channel and reduce heat transfer. Once the bubbles grow large enough, they are expelled from the channel and the nucleation and growth cycle begins again. The pool work considers submerged, heated SHPo surfaces such that the nucleation behavior can be explored in the absence of forced fluid flow. The surface is maintained at a constant temperature and a range of temperatures (40 - 90 °C) are explored. Similar nucleation behavior to that of the microchannels is observed, however, the bubbles are not expelled. Natural convection coefficients are computed. The surfaces with the greatest amount of nucleation show a significant reduction in convection coefficient, relative to a smooth hydrophilic surface, due to the insulating bubble layer.
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El-Hawat, Salem M. "Numerical modelling of flow and heat transfer for high-performance surfaces." Thesis, University of Brighton, 2003. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.251804.
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Skouvaklis, Gerasimos. "Rubber friction on ice and snow surfaces." Thesis, University of Edinburgh, 2011. http://hdl.handle.net/1842/9582.
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The friction of rubber on ice and snow surfaces is complex. Deeper scientific understanding is important for optimising performance of tyres in winter. Rubber, ice and snow systems exhibit frictional behaviour which depends on their material properties. The viscoelastic nature of rubber results in a higher real contact area compared to most other solids. At temperatures close or below the glass transition temperature, the frictional behaviour of rubber changes and its hardness increases. Thus, the real area of contact decreases, while the dissipation in the bulk of the rubber increases. Sliding of rubber on ice or snow leads to a temperature increase at the interface because of frictional heating, this can cause the surface to melt which decreases friction significantly. In this study we measured the friction of rubber on ice and snow and related the behaviour to mechanisms that occur. Key parameters affecting friction were examined and quantified. For this work a cold room and a new linear tribometer were specially designed and constructed. The rubber samples were made from various compounds and had different geometries. Typically they were the size of a “tread block element”. The geometries were chosen systematically to investigate the effects of surface area, sharp/rounded edges and sipes (small slits in the tread block that are used on snow tyres). A significant part of the work was developing consistent and reproducible ice and snow surfaces. New protocols were devised for these. The ice surfaces were made of de-ionised water, tap water and de-ionised water with salt. For the snow surface production: artificial snow was made and then compacted in a specially manufactured press, resulting in hard packed snow tracks for testing. Static and dynamic friction were investigated. Both were affected by speed, load, temperature and ice composition. The dynamic friction behaviour on ice was explained in terms of melt-water formation and the real area of contact of the rubber. The static friction was significantly affected by the losses inside the rubber bulk, the adhesive forces at the interface, and the time of stationary contact before the test. The investigation of rubber sliding on snow showed some similarities with sliding on ice; the surface of the rubber block slides over snow particles resulting in similar mechanisms as are seen on ice. However with snow there can also be a “ploughing” effect, where snow is cut by the leading edge of a sharp tread block. This effect contributes to friction. Experiments were made with simple rounded edged samples to avoid ploughing; the results showed the same trends as seen on ice, i.e. lower friction with increased speed, load and temperature. Investigations of siped tread blocks showed the same friction at low speeds as tread blocks without sipes. At higher speeds siped blocks exhibited less, or no, decrease in friction; more sipes gave less friction decrease. Our industrial collaborator, Michelin, made vehicle tests on snow using whole tyres with similar tread blocks. The trends they found were identical to our tests despite the dynamics of the system being more complex. This indicates how powerful the approach of using simple systematic experiments is for generating deeper understanding of the processes involved in sliding on ice and snow.
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Kuegler, Kurt W. "Heating, ventilation and air conditioning engineering and design /." Online version of thesis, 1990. http://hdl.handle.net/1850/10982.
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Akinwale, Olawale A. (Olawale Akintunde). "System architecture design of a robust heating system." Thesis, Massachusetts Institute of Technology, 2017. http://hdl.handle.net/1721.1/110130.
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Thesis: S.M. in Engineering and Management, Massachusetts Institute of Technology, School of Engineering, System Design and Management Program, 2017.Cataloged from PDF version of thesis.
Includes bibliographical references (pages 67-70).
Power outages are exponentially increasing because extreme weather conditions are occurring more frequently. In addition, the duration of the power outages are increasing. Unfortunately, the will to expand or convert the current electric grid is not there. The objective of this thesis is to design a new system - at a high level - that would protect homeowners from the effects of power outages. To do this, interviews were conducted with people who have actually experienced power outages during winter. Their preference for continued space heating during power outages prompted a design that uses natural gas fuel cell to power a furnace (or boiler) independent of the electric grid. The same system could also provide electricity to the homeowners, if the furnace is turned off. In addition to the system architecture design, surveys were conducted to determine pricing and financial analyses were performed to determine the commercial viability of the design. Consequently, the design proved to be too expensive. What's more, prices would have to drop significantly and / or other stakeholders, such as utility companies, insurance companies and governments, would have to cover most of the cost of the product for there to be a mass adoption.
by Olawale A. Akinwale.
S.M. in Engineering and Management
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Pougnet, Michel Andre Bruno. "Design of microwave heating equipment for laboratory applications." Doctoral thesis, University of Cape Town, 1993. http://hdl.handle.net/11427/17410.
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Includes bibliographical references.General purpose pressure vessels for digestion in microwave ovens have been developed and their applications investigated. The vessels were manufactured from PTFE and polypropylene and included a safety valve. The easily manufactured vessels were found to be reliable for a wide range of samples. A small vessel of 10 ml capacity, also constructed from PTFE and polypropylene, was developed for very small samples. These were used for the digestion of blood. A design for a simple modification of microwave ovens for use in the laboratory has been investigated. A Sharp microwave oven was lined with polypropylene and an extraction system that worked by the Venturi effect was used to remove the fumes from the cavity of the oven. This modification was found to be adequate to prevent corrosion of the oven and to provide the necessary safety features required for a laboratory system. In another modification, a thermocouple and a controller were used for maintaining the temperatures of the samples. Ports were available at the top of the cavity for insertion of suitable vessels for a variety of investigations. A computer-controlled waveguide has been designed for general laboratory applications. The temperature of the samples could be monitored and controlled. The waveguide was used for investigating sample digestions and the heating characteristics of a wide range of materials. A cylindrical applicator has been developed for the microwave heating of large (ca. 300- 600 ml) samples. Temperature monitoring and control was achieved through the use of a thermocouple and a computer. The instrument was found useful for many laboratory investigations involving relatively large samples. A new applicator has been developed for the even heating of multiple laboratory samples. The vessels (tubes) were introduced into the multimode cavity through ports. A choke was developed to allow rotation of the ports and the samples inside the cavity. Vapours could be extracted from the vessels outside the cavity using a fume extraction system. This system was found to be safe in terms of microwave leakages and yielded very good evenness of heating.
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Grimes, Mikal Keola. "Vacuum heating absorption and expansion of solid surfaces induced by intense femtosecond laser irradiation /." Digital version accessible at:, 1998. http://wwwlib.umi.com/cr/utexas/main.
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Kruithof, Nico Gerard Hugo. "Envelope surfaces surface design and meshing /." [S.l. : [Groningen : s.n.] ; University Library Groningen] [Host], 2006. http://irs.ub.rug.nl/ppn/292152264.
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Lerner, Scott Allen. "Optical design using novel aspheric surfaces." Diss., The University of Arizona, 2000. http://hdl.handle.net/10150/289160.
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Advancements in the design, manufacturing and testing of optical systems have created the need for new functional representations for aspheric surfaces. The representations must define surfaces that can compensate for a high degree of wavefront asphericity and represent steeply sloped surfaces as the surface normal becomes perpendicular to the optical axis. As the standard asphere is explicitly defined, the range of surfaces that it can properly describe is limited. This work develops both a parametrically defined surface approach and an implicitly defined surface approach. Whereas the surface sag of an explicit surface is defined directly using one equation, the sag of a parametric surface is defined using at least two equations. The sag of an implicit surface is defined indirectly using a surface function. The utility of these novel approaches is demonstrated using examples of current interest. Specifically, a truncated parametric Taylor surface and an implicit xyz-polynomial surface are shown to be more general definitions that represent highly aspheric surfaces better the standard explicit asphere. Ray tracing and optimization strategies for parametric and implicit surface representations are discussed. Additionally, this work shows that a Fourier series is not a useful optical surface and introduces the explicit superconic surface, which is a redefinition of the standard superconic surface. Finally, we compare the surface types discussed for ray tracing speed, optimization complexity, and ability to represent highly aspheric surfaces.
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Rios, Neyra César. "Design of mechanoresponsive surfaces and materials." Thesis, Strasbourg, 2013. http://www.theses.fr/2013STRAE019/document.
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Le but de ma thèse a été de concevoir des matériaux chimio-mécano répondants, des matériaux capables de permettre une transformation chimique réversible lorsqu’ils sont soumis à un stress mécanique. Tous les systèmes conçus ont été développés sur des substrats en silicone. Une première approche a consisté à créer des surfaces à sites cryptiques où une biotine est enfouie dans des brosses de chaines de poly(éthylène glycol). Le système streptavidine/biotine a été utilisé comme modèle. Ces surfaces sont anti-adsorbantes à la streptavidine sauf lorsqu’elles sont étirées à 50% où la biotine est reconnue mais les surfaces sont non réversibles. Dans une seconde approche, nous avons modifiés la surface du silicone par adsorption d’une multicouche de polyélectrolytes. Cette stratégie est basée sur la réticulation covalente du film par l’enzyme β-galactosidase modifiée. Nous sommes ainsi parvenus à créer une surface présentant une activité catalytique modulable par l’étirement mécanique, et ce, d’une façon partiellement réversible. Ce travail représente le premier exemple d’un système où une contrainte mécanique imposée à un matériau permet la déformation conformationnelle d’une enzyme et ainsi la diminution de l’activité catalytique. Dans une dernière approche, nous avons conçu un système mixte composé d’un substrat de silicone sur lequel un gel de polyacrylamide est greffée de façon covalente. Des enzymes ou des mécanophores pourront ainsi être inclus dans le réseau polymérique du gel de polyacrylamide et être étirés. Nous sommes parvenus à préparer de tels systèmes où l’hydrogel reste solidaire du film de silicone, sans apparition de craquelures jusqu’à 50%d’étirementThe goal of my PhD was to develop new routes to design chemo-mechanoresponsive materials, materials that respond chemically to a mechanical stress, in a reversible way. All the systems designed during my PhD thesis were based on the functionalization of silicone sheets. First we created cryptic site surfaces by embedding biotin ligands into PEG brushes. The couple streptavidin/biotin was used as a model system. At rest, the surface so-prepared was antifouling and biotin ligands were specifically recognized by the streptavidin when the surface was stretched at 50%. Unfortunately, in this first approach, the mechanosensitive surface did not lead to a reversible process. In a second approach, we modified the silicone surface by using the polyelectrolyte multilayer (PEM) film deposition. This strategy was based on the covalent cross-linking of modified enzyme, the β-galactosidase, into the PEM. We succeeded in modulating the enzyme activity in the film under stretching and this approach appears as partially reversible under stretching/unstretching cycles. This work represents the first reported system where enzymatic activity can be modulated by stretching due to modulation of the enzyme conformation. In a last approach, we also designed a mixed system consisting of a silicone sheet onto which a polyacrylamide hydrogel is covalentlyattached with the goal to create a stretchable gel into which one can covalently attach enzymes or chemical mechanophores. These enzymes or mechanophores can thus be put under mechanical stress. We succeeded in creating a system that can be stretched up to 50% without detachment of the gel from the silicone and without inducing cracks in the gel
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Sabra, Ahmad. "Nonlinear PDE and Optical Surfaces Design." Diss., Temple University Libraries, 2015. http://cdm16002.contentdm.oclc.org/cdm/ref/collection/p245801coll10/id/345398.
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MathematicsPh.D.
We introduce two models to design near field reflectors in R^3 that solve an inverse problem in radiometry, taking into account the inverse square law of irradiance. The problem leads to a Monge-Ampere type inequality. The surfaces in the first model are strictly convex and require to be far from the source to avoid obstruction. In the second model, the reflectors are neither convex nor concave and do not block the rays even if they are close to the source.
Temple University--Theses
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Min, Hyerim Choi. "Encountered surfaces /." Online version of thesis, 1993. http://hdl.handle.net/1850/11971.
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Wright, Jonathan A. "The optimised design of HVAC systems." Thesis, Loughborough University, 1986. https://dspace.lboro.ac.uk/2134/7291.
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The workable design of HVAC (Heating Ventilating and Air Conditioning) systems is based upon sizing the components individually to meet a peak duty of a nominal operating point. Growing economic pressure demands more cost effective and efficient designs, but the appraisal of alternative solutions is limited by short design and construction times. The design of HVAC systems can benefit from the application of numerical optimisation methods as these allow the rapid appraisal of alternative schemes and the sizing of the components simultaneously for criteria such as minimum first cost, operating cost, life—cycle cost or primary energy consumption. Optimisation problems can be categorised according to the characteristics of the functions used to appraise the solutions and those of the constraints on the problem. This thesis discusses the formulation of EVAC system design problems in this context and describes the development of an optimisation procedure which is based upon a data base of manufactured components and operating parameters such as controller setpoints, mass flow rates and temperatures. The thesis describes several objective functions used in the appraisal of solutions and describes the use of constraint functions in restricting the solution to a practicable design. UVAC system optimised design problems can be solved using direct search methods. The implementation of three direct search algorithms is described and the limitations of each discussed. Conclusions are drawn and the characteristics of HVAC system optimised design problems used to make recommendations for the future development of an idealized algorithm. The thesis describes the development and structure of the optimised design program and its integration with an existing suite of simulation programs. The application of the program to the design of example heat recovery systems is given and the potential use of the software in other applications described together with proposals for the development of the procedure as a design tool.
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Pangalos, Georg [Verfasser]. "Model-based Controller Design Methods for Heating Systems / Georg Pangalos." Berlin : Neopubli GmbH, 2016. http://d-nb.info/1103874276/34.
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Ludman, John. "Evaluation and design of polymer systems for enhanced microwave heating." Thesis, This resource online, 1994. http://scholar.lib.vt.edu/theses/available/etd-06112009-063233/.
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Khushrushahi, Shahriar Rohinton. "A quantitative design and analysis of magnetic nanoparticle heating systems." Thesis, Massachusetts Institute of Technology, 2005. http://hdl.handle.net/1721.1/35600.
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Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, February 2006.Includes bibliographical references (leaves 81-89).
Magnetic particles under the influence of an alternating magnetic field act as localized heating sources due to various loss mechanisms. This effect has been extensively investigated in hypothermia studies over the past decades and has recently been applied at the molecular level to control the dehybridization of DNA molecules. As a result, it has the potential of controlling and studying biological systems. To ensure that the nanoparticles are the only source of heat requires a very efficient system that minimizes heat transfer from sources other than the magnetic field. A quantitative analysis of the requirements and the design of such a system was investigated and tested experimentally. Although the results were affected by transmission line effects, the theory supporting the approach is sound and explains the crucial parameters that are necessary for optimizing localized ferromagnetic nanoparticle heating.
by Shahriar Rohinton Khushrushahi.
S.M.
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Khan, Irshad. "Analysis and design of a high frequency induction-heating system." Master's thesis, University of Cape Town, 2003. http://hdl.handle.net/11427/17437.
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Includes bibliographical references.Advances in power electronic semiconductor technology are making high frequency converters for induction heating more feasible at power levels up to 50kW. This research presents the development and analysis of a solid-state induction-heating system, operating directly off single-phase mains frequency, which enables optimum and efficient operation over a frequency range of 80kHz to 200kHz. The system essentially comprises a DC-DC converter configured as a controlled current source, which feeds a load resonant DC-AC inverter, driving a parallel resonant load circuit. The load circuit comprises an induction-heating coil and a reactive power compensating capacitor. The systems active switching elements comprise power MOSFET's but can be extended to almost any other controlled power devices such as IGBT's, BJT's, SCR's, GTO's or SIT's. An automatic frequency control system ensures that the DC-AC inverter drives the load at its resonant frequency, thereby achieving zero voltage switching of the power semiconductors. This operating mode always ensures maximum power transfer to the load as well as maximum operating efficiency of the DC-AC inverter. Driving the load at resonance presents an essentially resistive load to the DC-DC converter, thereby reducing the losses associated with a reactive load. A compact circuit layout combined with this optimum mode of operation eliminates the need for any snubber circuit components in both the DC-DC and DC-AC converters at this power level. An overview into various applications and technologies of induction-heating is presented in this research. A detailed analysis of the induction-heating coil and work- piece are presented in order to aid the design of the load circuit. The induction-heating technology overview presents various induction-heating power sources, discussing the configurations of various topologies. A brief mathematical analysis is used to describe the operation of power electronic converters employed in the induction-heating system developed for this research. The parallel resonant induction-heating load circuit is characterised mathematically, allowing for the determination of the optimum operating conditions. This is followed by a simulation analysis, which is used to gain insight into the problem of frequency control. The frequency control system is modelled and the steady-state error response evaluated under different input conditions. Experimental results on the system implemented, based on operating waveforms and efficiency measurements of the solid-state induction-heating system are presented along with recommendations for future work. The implemented power source was tested at a maximum power of 2.3kW at 151kHz. A system efficiency of 86% at 1.3kW was measured when operating at 138kHz. This design however, provides for scaling to power levels up to 50kW. The induction-heating system's frequency tracking capability is evaluated by heating a steel work-piece through its Curie transition temperature. The induction-heating system is used to heat a 26mm x 35mm stainless-steel billet (work-piece) to 1200°C in 130 seconds using the calculated power of 1.35kW .
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Lau, Anthony Ka-Pong. "Development of a design procedure for greenhouse solar heating systems." Thesis, University of British Columbia, 1988. http://hdl.handle.net/2429/28853.
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The techniques of computer modeling and simulations are used to develop a design procedure for greenhouse solar heating systems.
In this study a flexible computer program was written based on mathematical models that describe the various subsystems of the solar heating system that uses the greenhouse as the solar collector. Extensive simulation runs were carried out for predicting system thermal performance, and subsequently correlations were established between dimensionless variables and long term system performance.
The combined greenhouse thermal environment - thermal storage model along with the empirical relationships and the values of constants approximated in the simulation yielded reasonably accurate computed results compared to observed data. The computer model was then applied to predict the system behaviour using long-term average climatological data as forcing functions. A parametric study was made to investigate the effects of various factors pertinent to greenhouse construction and thermal energy storage characteristics on system performance. The key performance indices were defined in terms of the 'total solar contribution' and the 'solar heating fraction'.
Correlations were developed between monthly solar load ratio and total solar contribution, and between total solar contribution and solar heating fraction. The result is a simplified design method that covers a number of alternative design options. It requires users to obtain monthly average climatological data and determine the solar heating fraction in a sequence of computational steps.
A crop photosynthesis model was used to compute the net photosynthetic rate of a greenhouse tomato canopy; the result may be used to compare crop performance under different aerial environments in greenhouses equipped with a solar heating system. This research program had attempted to generate technical information for a number of design alternatives, and as design optimization of greenhouse solar heating is subject to three major criteria of evaluation: thermal performance, crop yield and cost, recommendations were put forward for future work on economic analysis as the final step required for selecting the most cost effective solution for a given design problem.Graduate and Postdoctoral Studies
Graduate
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Taleb, Riadh. "Design géométrique de surfaces de topologie arbitraire." Phd thesis, Université Joseph Fourier (Grenoble), 2001. http://tel.archives-ouvertes.fr/tel-00004706.
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Cette thèse est consacrée à la définition d'une surface géométriquement lisse interpolant un ensemble triangulé de points de R^3. Une telle triangulation, que nous appelons "réseau surfacique", doit définir une sous-variété de dimension 2, et peut représenter des surfaces de n'importe quel genre topologique. Il fournit l'information topologique, par l'intermédiaire d'une structure de données contenant les informations d'adjacence entre les sommets, les arêtes et les faces. Nous avons développé deux méthodes pour l'interpolation des sommets du réseau surfacique. Elles sont strictement locales et produisent des surfaces polynomiales par morceaux de degré 5 et de continuité G^1. De nombreux paramètres libres sont disponibles et ajustés soit interactivement soit automatiquement afin de lisser la surface. Dans le contexte interactif, plusieurs outils de design sont développés, basés sur l'interprétation géométrique des paramètres libres. La forme voulue peut être obtenue par une modélisation temps réel, grâce à la localité des algorithmes. Dans le cas du design automatique, de nombreux algorithmes ont été developpés satisfaisant un certain nombre de caractéristiques de forme. Un grand nombre de règles heuristiques et d'optimisations locales sont utilisées pour définir les valeurs des paramètres de forme dans le but d'obtenir des formes satisfaisantes ainsi qu'un contrôle optimal de la surface.
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Hall, Peter Reginald. "Aspects of optical-design using aspheric surfaces." Thesis, University of London, 2003. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.399573.
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Go, Han Suk. "The design of broadband radar absorbing surfaces." Thesis, Monterey, California : Naval Postgraduate School, 1990. http://handle.dtic.mil/100.2/ADA240521.
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Thesis (M.S. in System Engineering in Electronic Warfare)--Naval Postgraduate School, September 1990.Thesis Advisor(s): Atwater, H.A. Second Reader: Janaswamy, R. "September 1990." Description based on title screen as viewed on December 29, 2009. DTIC Identifier(s): Radar absorbing materials, radar cross sections, radiation absorbers, lossy dielectrics. Author(s) subject terms: Wave absorber, dielectric material. Includes bibliographical references (p. 55-56). Also available in print.
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Ünerdem, Yiğit Toksoy Macit. "Design of geothermal district heating system of Universiade 2005 Athletes' Village/." [s.l.]: [s.n.], 2005. http://library.iyte.edu.tr/tezler/master/makinamuh/T000386.pdf.
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Thesis (Master)--İzmir Institute of Technology, İzmir, 2005.Keywords: Geothermal energy, geothermal fields, district heating, feasibility, conceptual planning. Includes bibliographical references (leaves.70-72).
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Sánchez, Herranz Daniel. "DESIGN OF A SOLAR WATER HEATING SYSTEM IN A RESIDENTIAL BUILDING." Thesis, University of Gävle, University of Gävle, Department of Technology and Built Environment, 2009. http://urn.kb.se/resolve?urn=urn:nbn:se:hig:diva-4957.
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Karlsson, Ejwertz Viktor. "Design of user interface for heating, ventilation and air conditioning systems." Thesis, Karlstads universitet, Fakulteten för hälsa, natur- och teknikvetenskap (from 2013), 2014. http://urn.kb.se/resolve?urn=urn:nbn:se:kau:diva-34806.
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The project was carried out at Karlstad University during the spring of 2014 as a degree project for a Degree of Bachelor of Science in Innovation and Design Engineering and consists of 22.5 ECTS. The supervisor was lecturer Lennart Wihk from Karlstad University. The examiner was professor Leo de Vin. The project was conducted for Swegon AB and dealt with developing a user interface for systems regulating climate parameters in indoor environments, such as hotel rooms or office environments. The area of focus has been on developing the user interface with regard to end users, giving it the right functions and making it easy to understand. Suggestions about how user interfaces of this type could look was to be delivered to Swegon. The project started with creating a foundation. This was done through literature studies, benchmarking and interviews. The information gained here was used to put together a list of requirements which was later used as a guide when developing and evaluating concepts. Idea generation-methods were used to generate concepts and the concepts were developed further to later be voted on by employees at Swegon. The votes were evaluated and two concepts were developed, based on the the voting outcome. The concepts are inspired by wishes from the end users (expressed in the interviews) and are developed with regard to principles of design. The concepts were made into prototypes, in the form of 3D-printed models. The results of the project, in short: • Two image boards. One with thoughts about functions of existing climate related user interfaces written on it, and one with thoughts of different ways of illustrating air-temperature written on it. • Explanations of and reflections about functions of four different types of user interfaces for heating, ventilation and air conditioning (HVAC) systems. • Four product semantic analyses (PSA). Three of existing user interfaces for Swegon HVAC systems and one of a concept for a user interface for HVAC systems. • Interviews with six potential end users, written down to a large extent. • A compilation of the six interviews, written down in English. • An interview with an employee at Swegon service, regarding installation of user interfaces for HVAC systems, written down to a large extent. • A functional analysis, which in this project works as a requirements specification. • 10 ideas of concepts. • Two voting-systems which are developed for use when voting for several elements which can be combined to make up a holistic concept. The voting-systems are inspired by the "morphological analysis" described by Johannesson et al. (2009). • Two final concepts of user interfaces for HVAC systems with thorough descriptions in a table in this report. The concepts are developed with respect to end users and design principles. • Simplified versions of each of the two final concepts as CAD-models and as 3D-prints.
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Cemo, Thomas A. Van Treuren Kenneth W. "Design and validation of a solar domestic hot water heating simulator." Waco, Tex. : Baylor University, 2009. http://hdl.handle.net/2104/5357.
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Fernandez, del Castillo Lisa. "Design of a novel test bench for induction heating load characterization." Thesis, Massachusetts Institute of Technology, 2014. http://hdl.handle.net/1721.1/90135.
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Thesis: S.M., Massachusetts Institute of Technology, Department of Electrical Engineering and Computer Science, 2014.26
"June 2014." Cataloged from PDF version of thesis.
Includes bibliographical references (pages 87-89).
Magnetic materials used in induction heating applications have nonlinear magnetic properties with respect to field strength and frequency, which can be effectively characterized using experimental techniques. To this end, we present a test bench inverter optimized for induction heating experimentation, capable of driving an inductive load across a 1-100 kHz frequency range with up to 2 kW power. Harmonic distortion of the inverter is minimized with a novel multilevel topology and modulation scheme, thus allowing near-sinusoidal excitations to be obtained at varying field strengths and frequencies. To demonstration the capabilities of the test bench, we characterize the power dissipation of a loaded induction heating coil across a range of frequencies and power levels.
by Lisa Fernandez del Castillo.
S.M.
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Eisenstein, Jessica A. (Jessica Ann). "Design and construction of a Helmholtz coil apparatus for nanoparticle heating." Thesis, Massachusetts Institute of Technology, 2006. http://hdl.handle.net/1721.1/36307.
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Thesis (S.B.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 2006.Includes bibliographical references (p. 50-51).
Manipulating biomolecules can lead to better understanding how specific biological components function and can result in new therapeutic techniques. Biomolecules are manipulated by magnetically heating conductive nanoparticles attached to biomolecules within a radio frequency magnetic field generated by a coil. Currently, researchers monitor the effectiveness of this heating with UV/Visible spectroscopy. However, fluorescence spectroscopy would provide a more sensitive and versatile way to monitor the effects of magnetic heating. By using a Helmholtz coil pair, I have successfully created a coil set-up that can manipulate a sample of biomolecules within a fluorometer.
by Jessica A. Eisenstein.
S.B.
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De, Meyer Oelof. "Design considerations for low pressure solar water heating in South Africa." Master's thesis, University of Cape Town, 2012. http://hdl.handle.net/11427/22061.
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This thesis investigates the application of solar water heating in South Africa. The solar water heating system investigated work on the thermosiphoning effect or natural convection. An extensive literature study has been undertaken to investigate this phenomena. The three partial differential equations (governing equations) are non-dimensionalized and a similarity solution is applied to obtain two coupled non-linear ordinary differential equations. These equations are then solved in MATLAB to obtain the velocity and temperature profiles. Two scenarios were considered, a vertical wall with a constant wall temperature and a vertical wall with a constant heat flux. LP SWH systems use vacuum tubes to absorb solar radiation and transfer it to the water, which is similar to the vertical wall with a constant heat flux. A simulation model has been developed for a LP SWH system which is able to simulate the system performance for a given geographical location, where the user can specify the system component attributes. Experiments on the system were conducted to validate the simulation model. The simulation model accompanies a 6-Step Design Guide developed to assist the user to design a system able to satisfy the consumer's hot water demand. The 6-Step Design Guide developed can be used in future design considerations for LP SWH systems in South Africa.
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Al-Shaikhli, Ali K. M. "A novel method for the design of induction heating work coils." Thesis, Loughborough University, 1985. https://dspace.lboro.ac.uk/2134/27353.
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Induction billet heating is a well-established industrial process for preheating prior to forging, rolling and extrusion. In many cases the application of induction heating techniques has been hindered by the inability of existing methods of work coil design to easily produce a design which will give a non-uniform power density along the surface of a workpiece.
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Jerome, David. "Building load analysis and graphical display as a design tool." Thesis, Georgia Institute of Technology, 1997. http://hdl.handle.net/1853/16410.
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Diamond, James. "Specification and development of trimmed surfaces." Thesis, Queen's University Belfast, 1993. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.238971.
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Hossainzadeh, Bezminabady A. "Analysis and design of multilayer frequency selective surfaces." Thesis, Loughborough University, 1997. https://dspace.lboro.ac.uk/2134/12360.
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Structures that include more than one layer of Frequency Selective Surfaces (FSS) are an attractive feature in applications with stringent performance requirements. They provide extra flexibility with regard to the adjustment of the transmission responses which can in principle be insensitive to angle of incidence because of the increased bandwidth. This thesis deals with computer simulation and experimental assessment of a variety of multilayer FSS structures. The plane wave vector modal analysis technique is adapted for analysing the scattering from these multilayer FSS structures. The novelty in the plane wave modal analysis method lies in the fact that they can be applied to arbitrary lattice and element geometries. A novel super-resolution approach of analysing the scattering from FSS in cascade, with arbitrary lattice geometries of the two arrays is outlined. These type of structures exhibit multiresonant responses in a controlled manner. The problem of assigning different lattice geometries to the structure is addressed here by assigning the periodic fields adjacent to the arrays a common (or mutual) periodicity and by employing the convolution theorem to the modal (Floquet) sets that expands the tangential fields in each array. As a result, the spectral components of the Floquet mode coefficients from the various adjacent arrays are related to those of the common periodicity by means of a correlation function. This correlation function enables the spectral components of the Floquet mode sets expanding the tangential fields from any two adjacent arrays to be super-resolved from those of their common periodicity set. Once the convolution has been executed, application of electromagnetic boundary conditions are utilised, thus obtaining the coupled electric field integral equations. These integral equations relate the spectrums of the surface current densities to the various Floquet mode coefficients. The integral equations are in turn solved by the Method of Moment (MoM) technique for the unknown current coefficients from which the unknown transmission and reflection coefficients from the entire structure are obtained. A major assumption that is made in this technique for assigning a common periodicity lattice is that the ratio of lattice periodicities of any two adjacent arrays must be a rational number. The importance of the proposed technique lies in unlocking the complexities that exist when the scattered Aoquet modal coefficients from the arrays are related to the spectral components of the currents induced on the surfaces of the arrays, in the integral equation formulation. Furthermore, the proposed approach offers a computational advantage when applied to multilayer FSS structures, as it is invariant to the distance separating the arrays. A computer model based on this technique is developed for obtaining the prediction results. Various double layer FSS structures with arbitrary element types and lattice geometries of the arrays and with variable separation distances between the two layers are studied. The plane wave transmission coefficients of these multiresonant structures are computed with a v1ew to predict their radiation parameters. Extensive measurements are performed by using a purpose built experimental jig for mounting the structures, in an indoor anechoic chamber. The validity of the theoretical model is assessed by comparison with measurements from a variety of multilayer structures.
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Chalfant, Julie Steele. "Analysis and design of developable surfaces for shipbuilding." Thesis, Massachusetts Institute of Technology, 1997. http://hdl.handle.net/10945/7877.
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Developable surfaces are widely used in manufacturing with materials that are not amenable to stretching. Applications include the formation of ship hulls, ducts, shoes, clothing and automobile parts such as upholstery and body panels. In shipbuilding, developable surfaces are shaped using only rollers or presses. Heat treatment is then used only to remove distortion induced by welding or other means. Doubly curved surfaces, on the other hand, must be heat treated after rolling to induce the additional curvature. The heat treatment is normally done by hand, by a skilled artisan with years of training to achieve the correct amount of bending. This is an extremely time consuming, labor intensive and thus expensive process. According to Avondale/IHI Shipbuilding Technology Transfer data for a tanker, only 15.1% of the curved plates in a ship hull are singly curved, while 65.8% of the plates are doubly curved, requiring roller and heat treatment processes. An intensive effort to increase the amount of developable surfaces in the hulls of merchant ships at Burmeister & Wain Shipyard has resulted in a reported 20% reduction in manhours required to produce a hull. Designing a ship entirely of singly curved, or developable, surfaces would reduce construction costs even more. The main goal of this research is to develop a user-friendly method of designing developable surfaces with a B-spline representation. The effort is then extended to address some common differential geometry properties that will be useful in the design and manufacturing process. The ultimate goal is to provide a method to design a complete ship hull from developable surfaces and to generate cutting and bending information in a format that is user friendly for both the engineer and the worker. Although this thesis does not go that far, it takes a major step toward this goal
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El-Sheikh, Abdel Nasser Ahmed. "Advances in the design of frequency selective surfaces." Thesis, University of Kent, 1992. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.303156.
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Lin, You-Ning, and 林宥甯. "Design of Insert Type Induction Heating Module for Uniform Tool Surface Heating." Thesis, 2009. http://ndltd.ncl.edu.tw/handle/71638427719682988330.
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碩士國立成功大學
機械工程學系碩博士班
97
Injection molding is one of the major fabrication technologies, andmany manufacturers used it to fabricate products. In recent years,many products have the requirements including high surface quality,high gloss and high replication. And rising tool surface temperature is one of the solutions for the ones. So, many tool surface heatingtechniques have been developed recently. Due to the advantages ofelectromagnetic induction heating such as high speed heating, lowenergy consumption and environmental pollution reduction, using theone for tool surface heating is more significant among those tool surface heating techniques.In the past, the studies of using electromagnetic induction heating for tool surface heating indicated that the temperature uniformity and increasing cycle time were questionable until now. In this thesis, the insert type induction heating module will be developed to improve those problems. According to the result of coil test experiments, the surface temperature of 7mm thickness hot work die steel (JIS SKD61) could rise from 50oC to 150oC in 15 seconds and the temperature uniformity of heated zone reached 94%~95%.In this thesis, the parallel type coil and magnetic flux concentrators were adopted to fabricated induction heating apparatus. And the insert type induction heating module was developed successfully. This induction heating module could heat the target area of mold cavity uniformly. The uniformity of target area reached 94%~96%. And the heating rate of this module is about 3.5oC/sec
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Mei-HuiLai and 賴美惠. "Design of Rapid Mold Surface Heating System." Thesis, 2010. http://ndltd.ncl.edu.tw/handle/05538051542143864893.
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碩士國立成功大學
航空太空工程學系碩博士班
98
Nowadays consumers have paid more attention to the cosmetic appearance of the products. Because of the cooling contraction as the hot plastic melt contacts the low mold temperature in the tradition injection molding process, the product may have some distortion and affect the product’s appearance. This research focuses on mold temperature management. By heating the mold surface to a higher temperature dynamically, the cosmetic quality of the molded product may be enhanced while not increasing the cycle time largely. This research expects to introduce a new mold design that can heat the mold surface rapidly and uniformly. A movable block is designed and integrated to the mold, the movable block is divided into the heating zone and the cooling zone. Cylindrical electric heaters are used to heat the heating zone of the block to the setting temperature. During heating, the heating zone iii of the movable block moves to the position under the mold cavity to heat the cavity surface. During cooling, the cooling zone of the movable block moves back to the position while the heating zone moves out. The mold surface heating and the temperature distribution are simulated using Ansys software to confirm the feasibility of this design.
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Yang, Che-Wei, and 楊哲瑋. "Study of Gas-Assisted Heating Associated with Mold Design Applied to Improve the Heating Efficiency on Mold Surface." Thesis, 2008. http://ndltd.ncl.edu.tw/handle/88992636365908349036.
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碩士中原大學
機械工程研究所
96
With the rapid development technology at the moment, the needs for 3C products are also increasingly, especially the appearance of products, which is the key for consumers to decidedly whether or not to purchase it. During manufactory products are mainly produced by injection molding, in order to get better products. mold temperature control is one of the most direct and it is cheap. Generally, it traditional mold temperature technology is to effectively raise temperature, then cycle time will be increased a lot. Therefore, in the recent years, dynamic mold surface temperature technology has become a new found technology. In this study, It would mainly talk about heating the mold surface use the air and discuss about the heating benefit. At the beginning, find the data according to temperature-changing, which retrieving by 20 intervals every second, for accurate temperature. Then, making basic experiment of gas heating, and change the shape to make the uniformity of heating better, when the uniformity of heating has improvement of , I would focus on the modification of coating to improve the heating benefit. Finally, makes the comparison with traditional mold temperature control in order to confirm the result of heating benefit. After the experiment, using CFD-ACE analysis to test and verity which confirm the study. After experiment, the best benefit could be raise 33 ℃ every second. The speed of heating is special fast. In the analytic result that only has a little error with experiment. Therefore, it conformable that contributions and practicability of the study.
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Chiu, Yu-Ching, and 邱昱晴. "Effect of Mold Design on Mold Surface Heating in Injection Molding." Thesis, 2009. http://ndltd.ncl.edu.tw/handle/30191465086532073753.
Full textAbstract:
碩士國立成功大學
航空太空工程學系碩博士班
97
Injection molding is an important fabrication process for polymer plastics with the advantages of mass production, fast and low cost. Its applications are quite broad in appliance, electronics, and anformative, etc. In this decade, a lot of commercial products become smaller and lighter. The relevant techniques for high demand on appearance and quality improvement bring the better products to consumers. Thin-walled injection molding is usually molded under high mold temperature and high injection pressure. Methods to raise the mold surface temperature have been investigated by many scholars. The research concentrates on the study of a rapid surface heating system for injection molding. This study explores the effects on mold surface heating efficient by changing the mold structure and design by inserting PTFE. The result shows that the simply open channel on mold surface doesn’t have the effect of increasing heating efficient. The mold design with an inserting PTFE into the bottom of cavity can raise the surface temperature about 33℃and it doesn’t affect the cooling time.
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Tsai, Sheng-wei, and 蔡勝崴. "Design and Simulation Analysis of Induction Coil for Rapid Mold Surface Heating." Thesis, 2012. http://ndltd.ncl.edu.tw/handle/98837271173874520504.
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碩士國立高雄第一科技大學
機械與自動化工程研究所
100
With the advantages of high efficiency, environmental protection, energy saving, safe operation, and good controllability, electromagnetic induction heating is suitable to the variotherm injection molding process. A high mold temperature setting by induction heating has been proved to effectively improve the melt flow property during the filling process, and thus can obtain good appearance and replication quality of molded parts. In the past studies, influences of coil turns, induction frequency, and induction distance on the performance of induction heating have been widely investigated, however factors of workpiece thickness and position of induction coils are rarely studied. These two factors are thus focused in this investigation. In this study, the commercial simulation software COMSOL Multiphysics and the Taguchi method both are used to analyze the heating rate and temperature uniformity of heating surface. Qualities of high heating rate and small temperature deviation are chosen in the Taguchi analysis. As to the control factors, they consist of workpiece thickness, coil space, induction distance, coil offset, induction frequency, and idle time after heating. Additionally, the principal component analysis method is applied to obtain the best combination of design parameters for the purpose of achieving high heating rate and low temperature deviation. The simulation results show that the best combination is 10-mm workpiece thickness, 15-mm coil space, 5-mm induction distance, zero coil offset, 35-kHz induction frequency, and 6-second idle time after heating, which are selected for further experimental verification. In addition, the experimental results reveal that thickness of workpiece is the most significant factor to heating rate. A thick workpeice will form a low heating rate and cause quick temperature dissipation after induction heating. Also, coil offset is significant to temperature uniformity of heating surface.
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Yu-TingSung and 宋昱廷. "Design of Non-Planar Induction Coils for Injection Molding Tool Surface Heating." Thesis, 2014. http://ndltd.ncl.edu.tw/handle/76714660263142763987.
Full textAbstract:
博士國立成功大學
機械工程學系
102
Recently, energy saving is one of the important issues for polymer processing industry. Electromagnetic induction heating has many advantages such as fast heating and low energy consumption. Previous studies using electromagnetic induction heating for rapid tool heating have indicated that the temperature uniformity on a cavity surface is not easy to be achieved. In this paper, a planar coil was used for heating uniform 30mm thick hot work tool steel (JIS SKD61) surface, another coil was used for 7 inch display frame tool and another non-planar coil was designed for a fax machine top case tool. The planar coil heating experiment results showed that temperature uniformity is about 88% and heating rate is 2℃ per sec. The 7 inch frame coil heating results showed that the temperature uniformity is about 90.90% and heating rate is 3.73℃ per sec. The non-planar coil heating result showed that the temperature of tool rose from 50℃ to 120℃ in 10 seconds.
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Huang, Yao-Lin, and 黃耀霖. "The Induction Coil Design Applied for Rapid Surface Heating of Injection Molding." Thesis, 2008. http://ndltd.ncl.edu.tw/handle/549rys.
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碩士國立高雄第一科技大學
機械與自動化工程所
96
The study aims to investigate the optimized designation of high-frequency electromagnetic induction coils, which are utilized in the rapid mold surface heating of injection mold, in order to realize rapid heating, uniform temperature distribution, and maximized heated area at even temperature. The study is mainly concerned with solving the unbalanced heat distribution of heated target at its cross and deep sections due to the approximate and skin effects most commonly occurring at the use of conventional single layer coil for induction heating. By adopting an injection mold plate the carrier of simulation and experiment, this work first employs the multiple physics coupling analysis technique simulated in the ANSYS software to predict the induction heating temperature profile. Integration of Taguchi method and principal component analysis (PCA) are then developed to search for the optimal design of induction coil and process parameters. The coil layer after optimization is further explored its effect on heating history. Lastly, the optimized induction coil and conventional single layer coil are compared with heating time required to reach 100℃ surface temperature and the maximal heated area at even temperature, defined as 5℃ variation. The experimental results that: (1) the optimized coil requires only 3 seconds to reach uniform temperature distribution and the working temperature raise to 190.1℃, as the conventional single layer coil is 168.3℃ and unable to reach balanced temperature after 11 seconds. (2) For repeatability testing of induction heating to 190℃ with optimized coil, the temperature variation is less then 5℃. (4) The power consumption of the optimized coil is 14.8% less than the conventional one.
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Zhong, Ren-Fan, and 鍾仁凡. "Design and Analysis of Halogen Lampshade for Rapid Micro-injection Mold Surface Heating." Thesis, 2005. http://ndltd.ncl.edu.tw/handle/99318669567188989746.
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碩士國立高雄應用科技大學
模具工程系碩士班
93
Abstract The objectives of this paper were to investigate the rapid micro-injection mold surface heating with infrared halogen lamps as well as lampshade designs. Taguchi’s method was used to obtain the optimal lampshade design. Four control factors were selected, which were reflector, focus of reflector, layout of lamps and gap size between the lampshade opening and mold surface. Their levels were as follows: Reflector had sphere, hyperboloid or paraboloid; Focus was 40mm, 50mm or 60mm; Layout of lamps had two-rows, one-row or arc-row; gap size was 2mm, 3mm or 4mm. In the analysis, first, the ray tracing for halogen lamp was simulated by CAE software-TracePro and heat-flux on the mold surface were obtained. Then, thermal analysis of the micro-injection mold was done by ANSYS. Finally, temperatures distributions on the mold surface V.S. heating time were obtained. In the experiment, first, three kinds of lampshades were made to heat the micro-injection mold surface , which were sphere-reflector with two rows lamps, sphere-reflector with arc row lamps and “ㄇ” pattern-reflector with one row lamps. Temperatures on the mold surface measured by infrared camera were to verify the accuracy of analysis. Secondly, a spiral mold was made for injection experiment, and flow lengths were measured for observing the effects of heating mold surface. Results showed that analysis results were in agreement with experiments. Also, sphere-reflector had higher heating efficiency than “ㄇ” pattern-reflector, because infrared rays could be easily concentrated by sphere-reflector. And also two-rows lamp layout had higher heating efficiency than arc row, that is, two rows lamps were mostly in the center of the lampshade, infrared rays could be easily concentrated. This paper presented that concentration of infrared ray was of great importance for lampshade designs. Optimum lampshade can be developed from this point, that is, small power lamp might be enough to heat large mold. And also, the heating efficiency of lampshade can be further improved if the reflector can be coated with a layer of high reflectance material and the mold surface plated with a layer of high absorptivity material.