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Umans, Ari S. „Small-scale Advanced Thermo-Adsorptive Battery prototype“. Thesis, Massachusetts Institute of Technology, 2015. http://hdl.handle.net/1721.1/101484.
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Thesis: S.M., Massachusetts Institute of Technology, Department of Mechanical Engineering, 2015.Cataloged from PDF version of thesis.
Includes bibliographical references (pages 57-58).
A significant effort is underway to develop an adsorption-driven system with the capacity to replace the heating, ventilation and air-conditioning (HVAC) system in an electric vehicle. This Advanced Thermo-Adsorptive Battery (ATB) system uses novel adsorbent materials and methods of optimizing transport properties, without which the desired energy and power densities are unattainable. The work in this thesis runs parallel to that effort, with the development of a small-scale version of the ATB. Two novel prototype designs are discussed. The first, though never fully operational, was an attempt to demonstrate the potential of ATB technology to be scaled to meet countless heating and cooling applications. The second prototype was designed to be a system for testing aspects of ATB operation on a small scale. This prototype uses small quantities of adsorbents, reducing material costs and shortening time scales, and has a great deal of operating flexibility, enabling a number of system conditions to be parametrically studied. Testing and experimental procedures have been developed, and preliminary experimental data have been used to ensure proper prototype operation. This prototype will continue to be used as a tool to characterize ATB system operation and aid in understanding the technology.
by Ari S. Umans.
S.M.
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Harpold, Adrian Adam. „Stream Discharge Measurement Using A Large-Scale Paticle Image Velocimetry Prototype“. Thesis, Virginia Tech, 2005. http://hdl.handle.net/10919/40870.
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Flow information is necessary in many diverse applications including water supply management, pollution control, irrigation, flood control, energy generation, and industrial use. New technologies have been developed for the establishment of stage-discharge relationships due to concerns about costs, accuracy, and safety of traditional discharge estimation methods. One emerging technology for measuring open-channel flow is Large-Scale Particle Image Velocimetry (LSPIV).
LSPIV is a system capable of measuring surface velocity by collecting and analyzing recorded images of the stream surface. LSPIV has several advantages over conventional discharge measurement techniques: LSPIV is safer, could be automated to reduce labor, and could produce â real-timeâ discharge measurements. Therefore, the overall goal of this study was to evaluate the accuracy and feasibility of using LSPIV to measure discharge in low-order streams. The specific goals were to develop and test a prototype under varying conditions in a laboratory flume, adapt the prototype for field conditions, test the accuracy of the prototype in the field, and assess and recommend improvements for LSPIV operation as a stream discharge measuring device.
The laboratory experiments results indicated that LSPIV accuracy was influenced by camera angle, surface disturbances and flow regime (Froude number), and particle seeding density. Camera angle was optimum around 15 degrees, with larger camera angles producing more error due to image distortion. Conditions at high Froude numbers likely produced out-of-plane displacement losses due to surface disturbances. Low Froude numbers also showed under-predictions, which were likely due to agglomeration of the tracer particles at low velocities. Finally, the laboratory results demonstrated that tracer seeding density should be maximized and that densities below three particles per interrogation window should significantly reduce LSPIV accuracy.
The LSPIV prototype was tested at two low-order streams after developing a field prototype and operating procedures. Under field conditions, the prototype acquired consistent images, performed the necessary image processing, and established rules for estimating input parameters. The accuracy of LSPIV was evaluated using a Flo-Mate 2000 current meter and a permanent weir. Overall, twenty discharge measurements were taken with each measuring device at Stroubles Creek and Crab Creek. The discharges measured ranged from 0.12 to 63 cfs, which corresponded to a large range of velocities, with both simple and complex flow patterns. Problems were encountered from surface glare reducing image quality at both sites.
The LSPIV prototype was accurate for most measuring conditions with a mean error of -1.7%, compared to the weir measurements. The LSPIV measurements tended to under-predict discharge at high stages and had greater error at moderate flows (up to 39%) compared to the weir. However, at low flow conditions LSPIV showed improved discharge accuracy over the current meter, in comparison to the weir measurements. The LSPIV discharge measurements were not statistically different from either the current meter or weir (á = 0.05). Finally, the LSPIV discharge measurements had an uncertainty of approximately ±14% (at a 95% confidence interval).
In conclusion, LSPIV accuracy can be degraded by surface disturbances, inadequate illumination, and poor seeding densities. However, LSPIV showed adequate accuracy with the potential to become competitive with conventional discharge measurement techniques and therefore, has the potential to reduce costs and increase the geographic extent of surface water monitoring networks.Master of Science
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Calvo, Catoira Marta. „Small caliber arterial prosthesis: prototype and pre-industrialization“. Doctoral thesis, Università del Piemonte Orientale, 2020. http://hdl.handle.net/11579/114874.
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Cardiovascular diseases represent the leading cause of death in developed countries. Modern surgical methods show poor efficiency in the substitution of small-diameter arteries (< 6 mm). Due to the mismatch in mechanical properties between the native artery and the substitute, the behavior of the vessel wall remains a major cause of inefficient substitutions an unsolved complication in surgery since 1970. The purpose of this work was to obtain polylysine-enriched vascular substitutes, derived from decellularized porcine femoral and carotid arteries. Polylysine was selected as a matrix cross-linker, increasing the mechanical resistance of the scaffold with respect to decellularized vessels, without altering the native biocompatibility and haemocompatibility properties.
The biological characterization showed excellent biological performances, while mechanical tests displayed that the Young’s modulus of the polylysine-enriched matrix was comparable to that of the native vessel. Concerning haemocompatibility, the performed analyses show that polylysine-enriched matrices increase coagulation time, with respect to commercial Dacron® vascular substitutes. Based on these findings, polylysine-enriched decellularized vessels resulted in a promising approach for vascular substitution.
In order to consider the industrial phase, a business plan (BP) and the preengineering of the production reactor were developed in the present project. Is crucial to consider the scale-up process of the project from the initial stages to increase the chances of its success. In this way, the feasibility study will contemplate the viability of the project from an economic point of view thus, the BP is the most important document of the study. From an engineering point of view, the industrial production reactor is the heart of the plant, so designing it from the outset will allow considering costs and performing the necessary experiments for its final design.
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Porter, Spencer. „A prototype of a centimeter-scale biomimetic fish using buckypaper composite actuators“. Tallahassee, Fla. : Florida State University, 2010. http://purl.fcla.edu/fsu/lib/digcoll/undergraduate/honors-theses/2181954.
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Thesis (Honors paper)--Florida State University, 2010.Advisor: Dr. Richard Liang, Florida State University, College of Engineering, Dept. of Industrial Engineering. Includes bibliographical references.
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Stallings, Brad L. „Design of a ship service converter module for a reduced-scale prototype integrated power system“. Thesis, Monterey, Calif. : Springfield, Va. : Naval Postgraduate School ; Available from National Technical Information Service, 2001. http://handle.dtic.navy.mil/100.2/ADA392078.
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Thesis (M.S. in Electrical Engineering) Naval Postgraduate School, December 2001.Thesis advisor(s): Ciezki, John G. ; Ashton, Robert W. "December 2001." Includes bibliographical references (p. 201-202). Also available in print.
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Saunders, Daniel Martin. „First data reconstruction and inverse beta decay analysis at the large scale SoLid prototype detector“. Thesis, University of Bristol, 2017. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.723466.
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Magnusson, Anton. „Hardware-In-the-Loop simulation of a small scale prototype of a Wave Energy Converter“. Thesis, Blekinge Tekniska Högskola, Institutionen för maskinteknik, 2020. http://urn.kb.se/resolve?urn=urn:nbn:se:bth-20698.
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Renewable energy sources are a hot topic, both when it comes to climate change and the constant increase in demand of electricity due to population growth and a more electrified society. One such energy source is wave energy - an energy source with great potential but still relatively new with the need for further development. Blekinge Institute of Technology (BTH) together with Ocean Harvesting Technologies (OHT) have made a collaboration to build a scaled Hardware-In-the-Loop (HIL) system of a power take-off (PTO) based on OHTs wave energy converter, InfinityWEC. The purpose is to teach the students at BTH about hydrodynamic and HIL simulations. A manual will also be written to help students perform the lab activities. A model of the HIL system will first be implemented in Matlab/Simulink, both with and without the WEC-Sim hydrodynamic simulation toolbox and simulations will be run to predict the system's behaviour. To parametrize the hydrodynamic model, the open-source Boundary Element Method (BEM) code, NEMOH, is used. The HIL system consists of electric motors, connected mechanically to each other with a coupling. One of the motors is the actuator, which applies torque to the second motor according to the simulated hydrodynamic loads on the buoy. The second motor on the other hand applies a torque according to the load connected to it or torque-controlled according to a selected control strategy. In this thesis two different types of loading is used: 1) resistive load without control of the generator drive, 2) resistive and capacitive load with reactive control of the generator drive. The load resistance can be changed within a limited range as well as the sea state. Data that can be collected are the position and angular velocity of the motors, the currents to and from the two motors and the voltage over the load capacitance. The project concluded that the compensation needed for the motors to get the true hydrodynamic force has little effect when using reactive control and that a protective capacitor is be needed between the actuator motor and the power supply to protect it from reverse current. Finally, this work demonstrated the effectiveness of HIL systems to execute simulations to test and validate PTO systems in wave energy converters. The advantages are that one can create representative wave loading without the presence of water and with ease test different sea states.Förnybara energikällor är ett hett ämne, både när det gäller klimatförändringar och den ständiga ökningen av efterfrågan av el på grund av befolkningsökning och ett mer elektrifierat samhälle. En sådan energikälla är vågenergi - en energikälla med stor potential men fortfarande relativt ny med behov av vidareutveckling. Blekinge Tekniska Högskola (BTH) vill tillsammans med Ocean Harvesting Technologies (OHT) konstruera ett skalat Hardware-In-The-Loop (HIL) system av power take-off (PTO) baserat på OHT:s vågenergiomvandlare, InfinityWEC. Syftet är att lära eleverna på BTH om hydrodynamik och HIL-simuleringar. En manual kommer också att skrivas för att hjälpa eleverna att utföra labbaktiviteterna. En modell av HIL-systemet kommer först att konstrueras i Matlab/Simulink, både med och utan WEC-Sim hydrodynamisk simuleringsverktygslåda och simuleringar kommer att köras för att förutsäga systemens beteende. För att bestämma de nödvändiga parametrarna för hydrodynamiska modellen används Boundary Element Method koden NEMOH. HIL-systemet består av elmotorer, som är mekaniskt anslutna till varandra med en koppling. En av motorerna är ställdonet, som tillämpar vridmoment på den andra motorn enligt de simulerade hydrodynamiska belastningarna på bojen. Den andra motorn tillämpar ett vridmoment enligt belastningen som är kopplad till den eller är moment reglerad enligt en vald kontrollstrategi. I denna avhandling används två olika typ av belastning: 1) resistiv belastning utan kontroll av generatorndrivdonet, 2) resistiv och kapacitive belastning med reaktiv kontroll av generatorndrivdonet. Belastningsmotståndet kan ändras inom ett visst intervall och lika så havstillståndet. Data som kan samlas in är motorernas position och vinkelhastighet, strömmen till och från de två motorerna och spänningen över last kapasitatorn. I projektet drogs slutsatsen att den kompensation som behövs för motorerna för att få den riktiga hydrodynamiska kraften har liten påverkan reaktiv kontroll används och att det behövs en skyddande kondensator mellan ställdonsmotorn och strömförsörjningen för att skydda den mot bakström. Slutligen visade detta arbete hur effektiva HIL-system är för att utföra simuleringar för att testa och validera PTO-system i vågenergiomvandlare. Fördelarna är att man kan skapa representativ vågbelastning utan närvaro av vatten och med lätthet testa olika havstillstånd.
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Hassan, Md Fuhad. „Experimental study of droplet actuation,splitting and particles manipulation using a cross scale digital microfluidics prototype“. Thesis, University of British Columbia, 2013. http://hdl.handle.net/2429/44244.
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Digital microfluidics (DMF) system or device can be used as a significant and useful tool for chemical, bio-chemical and bio-medical applications because of its capability to perform basic fluidic functions and sequential chemical reactions on miniscule (nanolitre) droplets with better precision and accuracy. Application of sufficient electric potential in a sequence of electrodes manipulates the droplet in an electro wetting on dielectric (EWOD)-based DMF system. The successful implementation and the reliability of an EWOD-based DMF system depends on perfect design and fabrication of the lab-on-a-chip or DMF chip and also on the successful demonstration of basic fluidic functions including droplet actuation, splitting, mixing and separation within the DMF system.
This thesis focuses on the study of the efficacy and feasibility of cost-effective fabrication of a cross-scale electrode design for EWOD-based digital microfluidics lab-on-a-chip (LOC) systems. The intended microfluidic operations on this LOC include droplet actuation, splitting and particles manipulation (separation). The main features of the proposed cross-scale digital microfluidics prototype include one or more reservoirs, a linear array of square and rectangular electrodes forming the channel for liquid droplets, and a separation site consisting of multiple strip electrodes known as the high density electrodes or the strip electrodes.
The fabrication process introduces newer dielectric materials (Cyanoethyl Pullulan (CEP) and S1813 positive photoresist) which result in a simpler fabrication of the proposed DMF prototype. The newer dielectric materials also enhance the functional quality by reducing the required voltage for droplet actuation and increasing the breakdown voltage. Successful droplet splitting has been demonstrated on the proposed cross-scale DMF prototype, and droplet actuation is investigated as the precursor for any operations including splitting. Dielectrophoresis (DEP) is applied to the strip electrodes of the proposed prototype to enhance the movement of particles. The non-uniform electric field generated by the DEP controls the motion of the particles. The strip electrodes are used to enhance the particle trapping and one-side (within the droplet) movement of the particles. A flawless cross-scale digital microfluidics prototype is built by optimizing the fabrication recipe.
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Alqhatani, Eid S., und Fahad A. Bin Huwaymil. „Analysis, design and implementation of a proof-of-concept prototype to support large-scale military experimentation“. Thesis, Monterey, California: Naval Postgraduate School, 2013. http://hdl.handle.net/10945/37579.
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Approved for public release; distribution is unlimitedFORCEnet Innovation and Research Enterprise (FIRE) is an enterprise computer-based solution developed to support large-scale experimentation in the Navy and Department of Defense. Every year, experiments are conducted such as Trident Warrior (TW) events to assess new capabilities developed to achieve FORCEnet concept. FIRE is also used to support experimentation in other projects and for other services. FIRE was built by the Naval Postgraduate School to provide the necessary tools for the coordination of the planning, execution and reporting of these experiments. Since its inception in 2003, FIRE has played an essential role in TW by empowering all stakeholders with the collaborative and management tools to perform tasks that were time-consuming and manpower-intensive in the past. However, a survey conducted a few years ago showed that FIRE lacks some required features and improvement in various areas needed to be considered. The objective of this thesis was to design, develop, and test a proof-of-concept prototype of an improved web-based application to support the coordination of large-scale experimentation to address the shortcomings of the old FIRE system. This was achieved by using the following: a modern design approach; the Model-View-Controller; a state-of-the-art framework; Oracle Application Development Framework; and powerful development tools such as Oracle JDeveloper and Oracle WebCenter.
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Vardon, Philip James. „Three-dimensional numerical investigation of the thermo-hydro-mechanical behaviour of a large-scale prototype repository“. Thesis, Cardiff University, 2009. http://orca.cf.ac.uk/54832/.
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This thesis describes the modelling of the thermo-hydro-mechanical behaviour of a large-scale experiment, carried out at SKB's underground research laboratory in Aspo, Sweden. The experiment, known as the Prototype Repository Project, was constructed in highly fractured granite rock and is scheduled to last 20 years. Results from the experiment are collected systematically by SKB from the initial rock characterisation to the highly instrumented installed material. The model applied is the thermo-hydro-mechanical model previously developed at the Geoenvironmental Research Centre (GRC). The GRC's current model was extended to successfully accommodate three-dimensional THM behaviour, including the development of a high-performance computing algorithm using both multi-threaded and message-passing programming paradigms to enable simulations to be completed in significantly reduced time. Model simulations have been conducted of both the pre-placement stage of the experiment and the post-placement operational phase. The results of the pre-placement phase have been used to aid the calibration of the simulation and provide confidence in the development of the operational phase simulation. In the pre-placement phase simulation, a pragmatic approach using a combination of an effective continuum model and a number of key discontinuities was employed. A domain of 100 x 100 x 160m was used, discretised into over 550,000 finite-elements. The simulations were able to reproduce three-dimensional highly anisotropic flow conditions shown in the experimental results. The post-placement operational stage was then simulated in three-dimensions using the same rock domain as for the pre-placement analyses, including the buffer material, and discretised into over 920,000 elements. A number of key features, including the anisotropic hydraulic behaviour, were captured. It was concluded that the geological conditions, backfill re-saturation and buffer re-saturation, including the micro-structural effects of the bentonite, are all important to the simulation of a high-level waste repository. Long term simulation results were also presented. A number of aspects were explored using two-dimensional analyses, including the macro/micro- structural interactions of the bentonite buffer. A time-dependant form of the hydraulic conductivity relationship was developed and yielded significantly improved results in long-term analyses. The behaviour of a fracture intersecting a deposition-hole was also investigated highlighting the importance of discrete fractures on hydration behaviour.
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Emilsson, Arvid, und Andreas Buhrgard. „Towards a prototype of a modular biogas system“. Thesis, KTH, Skolan för industriell teknik och management (ITM), 2019. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-259579.
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As of today, large unused potential for biogas production exist within the Swedish agriculturesector. The biogas production within this sector is, however, associated with several problems such as poor energy efficiency and non-profitable systems. This is to some degree due to lack of standardized technical solutions. International Micro BioGas AB (IMB AB) has been aided by KTH since 2014. This project investigates several innovations from IMB AB in regards to biogas production: - A mixing device- A building capturing waste heat from the digesters (building concept)- Insulation of the digester (cover concept)- Small-scale and modular package systems The innovations listed above are evaluated from energy, economic and environmental perspectives by doing a case study on the dairy farm Ogestad close to Gamleby, Sweden. Two cases are considered. In Case 1, the raw biogas is burned in a combined heat and power-unit (CHP) in order to produce electricity. In Case 2, raw biogas is upgraded in a small-scale upgrading unit to vehicle gas standards which is sold to the market. The results show that the mixing device is promising in terms of energy use. It is therefore recommended to move on with testing of the equipment. The cover concept and the building concept show similar performance from energy and environmental standpoints. The building concept is concluded not to be economically viable. The cost reduction by applying a modular concept where one product can be used on different sized farms is significant. However, the needed investment from the company is large. The goal of achieving a modular system is therefore concluded desirable. The subsidy from the Swedish board of agriculture covering 40 % of the investment cost, has a major impact on the profitability of the systems. Without this subsidy, the systems are not viable in terms of economy. In Sweden, the small-scale vehicle gasproduction (Case 2) was concluded the most profitable as well as the best-performing from energy and environmental standpoints.Inom den svenska jordbrukssektorn finns stor potential för utvidgning av biogasproduktionen. Det finns dock många problem med småskalig biogasproduktion, exempelvis olönsamma och energimässigt ineffektiva system. International Micro BioGas AB (IMB AB) har identifierat att detta till viss del kan bero på bristfälliga tekniska lösningar. Detta då det inte finns någon standardisering av teknik på området. IMB AB har, i samarbete med KTH, sedan 2014 arbetat med olika aspekter av småskalig biogasproduktion. Detta arbete undersöker ett antal innovationer och koncept från IMB AB rörande biogassystem: - En ny metod för omrörning- En byggnad som återvinner värmen från rötkamrarna (byggnadskonceptet)- Ett nytt sätt att isolera rötkamrarna (huvkonceptet)- Småskaliga och modulära paketlösningar Innovationerna och koncepten ovan utvärderas från ett energitekniskt, ekonomiskt och miljömässigt perspektiv genom en fallstudie på mjölkgården Ogestad nära Gamleby i Sverige. Två användningsområden för biogasen analyseras. I Fall 1 (Case 1) bränns rågasen i en kraftvärmeanläggning för att producera elektricitet och värme. I Fall 2 (Case 2) uppgraderas rågasen till fordonsgaskvalitet som sedan säljs till marknaden. Resultaten visar att den nya omrörningsmetoden är lovande ur ett energiperspektiv och enrekommendation är att gå vidare med tekniken och göra experimentella studier. Byggnadskonceptet och huvkonceptet visade likvärdiga resultat ur energitekniskt och miljömässigt perspektiv. Byggnadskonceptet konstaterades vara ineffektivt ur ett ekonomiskt perspektiv. Kostnadsreduceringen som uppnås genom att systemet är modulärt och därmed kan produceras i stor skala till olika gårdsstorlekar, är signifikant. Det krävs dock en stor investering från företagets sida. För samtliga fall är systemens lönsamhet starkt beroende av Jordbruksverkets subvention på 40 % av investeringskostnaden och utan den ökar företagetsinvesteringsbehov drastiskt. Med svenska förutsättningar är småskalig produktion av fordonsgas det mest lönsamma samt mest fördelaktiga ur ett miljö- och energiperspektiv.
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Lemarenko, Mikhail [Verfasser]. „The Belle II DEPFET Pixel Vertex Detector : Development of a Full-Scale Module Prototype [[Elektronische Ressource]] / Mikhail Lemarenko“. Bonn : Universitäts- und Landesbibliothek Bonn, 2013. http://d-nb.info/104527643X/34.
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Hidajat, Ivan. „A prototype of a full-scale SCADA system installation using an operator training simulator module as power grid“. Thesis, KTH, Skolan för elektro- och systemteknik (EES), 2016. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-196218.
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Modulen Operator Training Simulator (OTS) syftar till att hjälpa elkraftsystemsoperatörer att förbättra sina kunskaper av elkraftsystemets beteende. Många kraftföretag har integrerat OTS i sina SCADA-system för utbildningsändamål. Det samma gäller ABB som har en OTS integrerad i sitt Network Manager SCADA / EMS-system. Dock , vid användandet av OTS har Network Manager inte egenskaper såsom det skulle haf om det opererade ett riktigt elkraftnät. Detta projekt syftar till att lösa detta problem och ett alternativt tillvägagångssätt för OTS integration till SCADA föreslagits. Arbetet inleddes med en undersökning av ABB:s SCADA / OTS med en analys av dess avvikelser till ett faktiskt SCADA styrsystem. Efter en inledande fas som involverade testning och studera SCADA / OTS arbetsflöde, fortsatte arbetet med att skapa alternativa lösningar för att undanröja avvikelserna mellan de två systemen. Kärnan i projektet innefattade att konstruera, implementera och testa nya alternativ för integration av OTS och SCADA system. Den framtagna prototypens funktionalitet, nätverksarkitektur, kommunikationsprotokoll och dataflöde undersöktes och jämfördes med de egenskaper på ett SCADA-system för verklig drift. Resultaten av utvärderingen visade att prototypen var en bra representation av ett verkligt SCADA-system.The Operator Training Simulator (OTS) aims to help power system operators to improve their proficiency of the power system behavior in the current increasing complexity of the control system. Many power utility companies have integrated the OTS into their SCADA system (Walve & Edstrom, 1998) (Demjen, Kadar, Meszaros, & Szendy, 1994) for training purposes. There is no exception for ABB’s; they integrated the OTS into their Network Manager SCADA/EMS system, and it is the main tool for this project. However, the ABB’s SCADA/OTS suffers from incomplete real SCADA properties, e.g., PCU and RTU, due to its sandbox nature. Consequently, it does not realistically represent the full properties and functionalities of an actual SCADA system. To address this issue, an alternative approach for OTS integration to the SCADA has been proposed. The work started with an exploration of the current ABB’s SCADA/OTS with an analysis of its deviations to an actual SCADA control system. After a preliminary stage that involved testing and studying SCADA/OTS’s workflow, the work continued with creating alternative solutions to eliminate the deviations between the two systems. Then, the core work of the project involved implementation and testing the new alternative prototype since there is a possibility that KTH and/or ABB will use the simulator for a future project. To finalize the work, the prototype’s functionality, network architecture, communication protocols and data flow were examined and compared with the actual SCADA to evaluate the quality of the design. The results of the evaluation showed that the prototype was a good representation of a real SCADA system.
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Serwon, Daniel Morrow. „Comprehensive Manual for a Sweeping Gas Membrane Distillation Prototype and Design of a Field Scale Solar Nanofiltration Membrane Desalination Facility“. Thesis, The University of Arizona, 2016. http://hdl.handle.net/10150/613597.
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Approximately 35% of the population of the Navajo Nation does not have direct access to the electric grid and public water supply. Tribal members haul their potable and livestock water from public water systems that are located great distances from their homes. The Navajo Nation Solar Desalination Research Pilot Demonstration Project is designed to provide residents affordable livestock water. The same technology can later be adopted to provide potable water. The project has deployed an off-grid, prototype water purification unit at a demonstration site north of Leupp, AZ utilizing membrane distillation (MD) technology. A second prototype for the same purposes utilizing nanofiltration (NF) membrane technology has been designed, built, and operated at The University of Arizona. Through experimentation I confirmed information provided the manufacturer of the NF membrane, calculated the production rate to be 636 gallons per day, and calculated the cost of desalinated water to be $0.003 per gallon. Both systems use solar energy to desalinate brackish ground water and the second prototype will later be deployed at the same site for side-by-side comparison. A critical part of the project is the development of technology transfer methods that will help the community take ownership of the project. To accomplish this goal I have written a comprehensive manual that will be given to the Navajo Department of Water Resources. The demonstration site will act as an applied research site for investigation, demonstration, and training related to sustainable water and energy systems designed to address the needs of remote, rural communities in arid and semi-arid regions. The aim is to inform a regional plan for Southwestern Navajo Nation Chapters to address chronic water and energy shortages, demonstrate renewable energy application for water treatment of brackish ground water, evaluate trade-offs in energy and water supplies, and foster community development. The research and demonstration site has been developed by an interdisciplinary and collaborative effort between the Bureau of Reclamation, Apex Applied Technology, Inc., and The University of Arizona.
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Whitcomb, Bryan D. „Design and implementation of a high-power resonant DC-DC converter module for a reduced-scale prototype integrated power system“. Thesis, Monterey, Calif. : Springfield, Va. : Naval Postgraduate School ; Available from National Technical Information Service, 2001. http://handle.dtic.mil/100.2/ADA430967.
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Thesis (Electrical Engineer)--Naval Postgraduate School, September 2001.Thesis Advisor(s): Robert W. Ashton, John G. Ciezki, Todd R. Weatherford. Includes bibliographical references (p. 175-177). Also available online.
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Lindqvist, Sheila. „Evaluation of User Interface to Improve Documentation within the Elderly Care System“. Thesis, Linnéuniversitetet, Institutionen för datavetenskap och medieteknik (DM), 2019. http://urn.kb.se/resolve?urn=urn:nbn:se:lnu:diva-98503.
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The usability of a software product is dependent on the end-user and the context of use. Having a user-friendly user interface that is appealing and easy to learn and use is essential for improved human productivity. However, this is not always the case. For instance, the computer-based documentation system Siebel used within the elderly care system; is perceived by most nursing assistants as complicated. The goal here is to evaluate the usability of the system's user interface, applying the usability metrics stated in the ISO/IEC-9126-1 standards to quantify the effectiveness, efficiency, and user satisfaction of Siebel’s documentation system. A prototype user interface was developed for comparison with the current system. Likert-scale five-point scale; System Usability Scale (SUS) questionnaires were used to measure User satisfaction. The results mirrored that the participants preferred the newly developed prototype user interface to the existing user interface
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Ratovonkery, Julie. „DYNABIOSOL : Conception bio-inspirée d'une enveloppe solaire Photovoltaïque dynamique aux fonctionnalités évolutives“. Electronic Thesis or Diss., Chambéry, 2023. http://www.theses.fr/2023CHAMA027.
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L'urgence climatique, l'augmentation de demandes énergétiques et l'épuisement de ressources fossiles ont mené à des ambitions énergétiques et environnementales de plus en plus élevées. Dans le secteur de bâtiment, ces ambitions visent à des bâtiments résilients, durables, à faible impact environnemental et à énergie positive. L'innovation de l'enveloppe du bâtiment, qui est un élément clé de son efficacité énergétique, est donc primordiale. En effet, l'enveloppe est souvent conçue sur des bases de fonctionnalités statiques. Pourtant, elle devrait être comme une interface adaptative et multifonctionnelle, qui échange et exploite les effets de son environnement, afin d'assurer la qualité des ambiances intérieures et la production d'énergie de fonctionnement du bâtiment.Dans ce contexte, cette thèse consiste à la conception d'une facade adaptative à composants photovoltaïques (PV) intégrés. Les fonctionnalités adaptives sont visées tant pour l'amélioration de sa performance thermique que pour la maximisation de la production électrique des modules photovoltaïques. L'obtention d'un élément d'enveloppe, muni de fonctionnalités dynamiques et adaptatives, fait souvent recours à des systèmes mécaniques et de contrôles complexes. Pour cette raison, une approche de bioinspiration et l'utilisation des matériaux intelligents sont choisies pour obtenir des mécanismes d'adaptation flexibles et intelligemment low-tech.L'approche consiste à l'analyse thermique et électrique d'une facade photovoltaïque de base. Dans notre étude, elle est composée de modules PV bifaciaux, d'une lame d'air ventilée et d'un mur multicouche. Le principe est d'identifier des propriétés limitant cette facade à des fonctionnalités statiques. De cette manière, les êtres vivants en lien avec les propriétés identifiées et pouvant franchir ses limitations sont explorés. Par la suite, les matériaux intelligents pouvant assurer les stratégies bioinspirées sont sélectionnés afin de développer le nouveau concept. Enfin, la solution est validée grâce à des études expérimentales sur les échantillons de composants intelligents choisis et sur un prototype à échelle réduite de la facade. Des études numériques de faisabilité et d'analyse de performance énergétique à l'échelle du bâtiment sont également réalisées.Cette démarche a conduit à l'application de composants de bilames thermosensibles et réfléchissants sur le mur derrière les modules PV. Les bilames, en forme de lamelle rectangulaire sont disposés sur le mur en face des cellules PV. Lorsque la température augmente, ils fléchissent progressivement. Leur déformation cyclique permet d'ajuster les fonctionnalités de la facade suivant trois principes. Premièrement, en été, la facade photovoltaïque se rafraichit grâce à l'ombrage du mur et à la dissipation de chaleur par augmentation progressive de surface d'échange dans la lame d'air. Deuxièmement, en hiver, l'énergie solaire thermique est collectée soit en fermant la lame d'air ou par la valorisation de l'air préchauffée. Enfin, la production électrique des modules PV est optimisée grâce à la réflexion des rayons solaires vers la face arrière des modules bifaciaux par les bilames. Les études expérimentales et numériques réalisées ont permis de valider le potentiel du concept pour l'amélioration de l'efficacité énergétique, surtout pour l'augmentation de la production d'électricité et la performance thermique en étéClimate change, growing energy demand and depletion of fuel resources have led to increasingly high energy and environmental ambitions. These ambitions aim for resilient, sustainable, zero carbon and positive energy buildings in the building sector. Radical innovation in building envelope technologies is paramount as it is a key element in building energy efficiency. Indeed, the envelope is often designed on the basis of static functionalities rather than an adaptive and multifunctional interface. However, in the latter case, it would interact with and benefit from the effects of its external environment to ensure a comfortable indoor environment and the production of the building operating energy.In this context, this thesis consists in the design of an adaptive facade with integrated photovoltaic (PV) components. The adaptive functionalities are developed to improve both the thermal performance of the facade and the electrical production of the PV modules. Designing such an envelope element often requires complex mechanical and control systems to implement dynamic and adaptive functionalities. For this reason, we have chosen to adopt a bioinspiration approach and use smart materials to achieve flexible and low-tech adaptation mechanisms.The methodology involves the analysis of the thermal and electrical behaviour of a standard photovoltaic facade. In our case, it comprises bifacial PV modules, a ventilated air gap and a multilayer wall. The principle is to identify the properties limiting that facade to static functionalities. From this step, biological mechanisms related to the identified properties, and that can overcome the limitations are explored. Afterwards, smart materials enabling to implement the bioinspired strategies are selected. Finally, the outline of the new concept is developed with the principles involved. The solution is validated through experimental studies on the samples of the selected materials and on a reduced-scale prototype of the facade. Numerical feasibility studies and energy performance analysis at the building scale are also carried out.The developed solution consists in the application of thermosensitive and reflective bilayer components on the wall behind the PV modules. Those components are thin rectangular slats applied opposite to the PV cells. When the temperature rises, they gradually bend. Their cyclic deformation allows the adjustment of the facade functionalities according to three principles. First, in summer, the PV facade is cooled by shading the wall and dissipating heat through the increased thermal surface exchange in the air gap. Second, in winter, solar thermal energy is harvested by closing the air gap or recovering preheated air. Finally, the bilayers enhance the PV power output because of their high reflection of the irradiance to the backside of the bifacial PV modules. The experimental and numerical studies have validated the potential of the design to improve building energy efficiency, especially for increasing yearly electricity production and thermal performance in summer
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Laffont, Charlotte. „La conception du logement à l’expérience des sonorités – COLEXSON : Un prototype construit pour expérimenter à échelle 1 les ambiances sonores de demain depuis un logement ventilé naturellement“. Electronic Thesis or Diss., Université Grenoble Alpes, 2024. http://www.theses.fr/2024GRALH014.
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Dans les théories et pratiques architecturales et urbaines, dans les réglementations et les labels de la construction, le son est abordé principalement comme une source de bruit, de nuisance contre lequel il faut isoler le logement. Malgré cela, les constats répétés de manque de qualité sonore des lieux de vie révèlent l’insuffisance de cette approche et la nécessité d’aborder la conception sonore par des outils complémentaires.Comment introduire l’écoute dans la conception des logements collectifs afin qu’ils répondent aux enjeux de la ville de demain et participent à une bonne qualité de vie ? Les espaces intermédiaires, situés entre les écoutes de la sphère privée et celles de la dimension publique, jouent-ils un grand rôle dans les perceptions quotidiennes ? Que peut-on retenir du vécu sonore des usager.ère.s dans les formes architecturales construites qui pourrait intéresser la future écoute de la ville ?Pour y répondre, nous allons nous intéresser aux écoutes de trois catégories d’espaces intermédiaires dans des formes architecturales historiques et contemporaines : les espaces de transition (hall, cour intérieure, etc.), les espaces extérieurs aux abords des logements (terrasse partagée, toiture, balcon, etc.) et l’enveloppe bâtie (double peau, fenêtre).Pour imaginer les écoutes de la ville et du logement avec l’urbanité post-carbone nous allons nous intéresser aux sons des sociabilités, ceux du paysage naturel, aux sons technologiques et à ceux des mobilités. Dans la prospective d’une ville aux nombreux aléas climatiques, nous imaginons une diversité d’usages et de cultures, des programmations mixtes, des mobilités douces (moteurs hybrides et électriques notamment), des proximités et des voisinages apportés par la densité. Les épisodes caniculaires annoncés nécessitent dès à présent de penser à des moyens de rafraîchir les logements. Comment va-t-on pouvoir vivre dans la densité avec les sons du dehors ? Comment rafraîchir un logement par une ventilation naturelle tout en apportant une modulation de l’écoute ?Cette thèse, réalisée dans le cadre d’un contrat A.N.R.T.-C.I.F.R.E. au sein du B.E.T. LASA, est rattachée au laboratoire A.A.U.-CRESSON et à la chaire de recherche « Habitat du futur ». Nous sommes convaincus de l’importance de l’expérimentation pour répondre à l’ensemble de ces questions et intégrer l’écoute dans la pratique de l’architecture. C’est pourquoi nous testerons des outils concrets et appréhensibles par les acteur.ice.s d’un projet. Une analyse d’un projet à Villeurbanne (69), le macro-lot B, sera réalisée dès les premières phases de conception pour anticiper ses ambiances sonores et les modulations d’écoute qu’il pourrait apporter. La conception d’un prototype à échelle 1:1 d’ECHAfaudage SONore – ECHASON – visera à expérimenter ses futures ambiances depuis un logement ventilé naturellement et depuis ses espaces intermédiaires. N’ayant pas pu être réalisé dans sa taille maximale, ce seront finalement deux prototypes de dispositifs de ventilation naturelle intégrant un filtrage sonore qui ont été construits et expérimentés avec des acteur.ice.s du projet. Plusieurs bandes sonores anticipant des espaces intermédiaires du macro-lot B ont pu être expérimentées avec des futur.e.s habitant.e.s de ce projet. Les résultats obtenus ont permis d’aboutir à l’ébauche de trois cahiers des charges pour intégrer la dimension sonore dans les futurs concours d’architecture et d’urbanisme. La qualité de l’environnement sonore doit être intégrée à la conception des logements au même titre que les préoccupations sur l’ensoleillement, la qualité de l’air ou encore le confort d’été. Cela représente un enjeu social, économique et sanitaire. C’est en cela que ce travail défend l’idée d’une conception des logements par l’écoute qui ne se fasse plus uniquement de manière défensive ou corrective mais plutôt de manière créative et engagéeIn architectural and urban theories and practices, in building regulations and labels, sound is approached primarily as a source of noise and nuisance, against which housing must be insulated. Despite this fact, repeated reports of a lack of sound quality in living spaces have revealed the inadequacy of this approach, and the need for complementary tools to address sound design.How can we introduce listening into the design of multi-family housing so that it meets the challenges of tomorrow's city and contributes to a good quality of life? Do intermediate spaces, located between the private and public spheres, play a major role in everyday perceptions? What can we learn from users' experience of sound in built architectural forms that might be of interest to future city listening?To answer this question, we're going to look at three categories of intermediate spaces in historic and contemporary architectural forms : transitional spaces (hall, inner courtyard, etc.), outdoor spaces around dwellings (shared terrace, roof, balcony, etc.) and the envelope of the building (double skin, window).To imagine the sounds of the city and housing in post-carbon urbanity, we're going to look at the sounds of sociability, the sounds of the natural landscape, technological sounds and the sounds of mobility. Looking ahead to a city with many climatic hazards, we imagine a diversity of uses and cultures, mixed-use programming, soft mobility (hybrid and electric motors in particular), proximity enhanced by density. With heatwaves on the horizon, we need to start thinking about ways on how cooling our homes. How can we live in density with the sounds of the outside world ? How can we cool a home with natural ventilation, while at the same time modulating the listening experience ?This thesis, carried out under an A.N.R.T.-C.I.F.R.E. contract within the B.E.T. LASA, is linked to the A.A.U.-CRESSON laboratory and the "Habitat of the Future" research chair. We are convinced of the importance of experimentation in answering all these questions and integrating the listening experience into the practice of architecture. That's why, throughout this work, we'll be experimenting with concrete tools that can be grasped by those involved in a project. An analysis of a project in Villeurbanne (69), the « macro-lot B », will be carried out in the early design phases to anticipate its sound ambiances and the listening modulations it could bring. The design of a 1:1 scale prototype of ECHASON - ECHAfaudage SONore - will be intended to experiment with its future environment of a naturally ventilated dwelling and from its intermediate spaces. As the project could not be carried out to its maximum size, two prototypes of natural ventilation systems incorporating sound filtration were built and tested with the project's actors. Several soundtracks anticipating the intermediate spaces of macro-lot B were tested with future residents of the project. The results led to the drafting of three specifications for integrating the sound dimension into future architectural and urban planning competitions. The quality of the sound environment must be integrated into housing design in the same way as concerns about sunlight, air quality and summer comfort. This represents a social, economic and health issue. In this perspective, this work defends the idea of designing housing through listening, not anymore in a defensive or corrective way, but rather in a creative and committed way
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Toews, Leslie Marilyn. „The Development of a Monolithic Shape Memory Alloy Actuator“. Thesis, University of Waterloo, 2004. http://hdl.handle.net/10012/871.
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Shape memory alloys (SMAs) provide exciting opportunities for miniature actuation systems. As SMA actuators are scaled down in size, cooling increases and bandwidth, improves. However, the inclusion of a bias element with which to cycle the SMA actuator becomes difficult at very small scales. One technique used to avoid the necessity of having to include a separate bias element is the use of local annealing to fabricate a monolithic device out of nickel titanium (NiTi). The actuator geometry is machined out of a single piece of non-annealed NiTi. After locally annealing a portion of the complete device, that section exhibits the shape memory effect while the remainder acts as structural support and provides the bias force required for cycling. This work proposes one such locally-annealed monolithic SMA actuator for future incorporation in a device that navigates the digestive tract. After detailing the derivation of lumped electro-mechanical models for the actuator, a description of the prototyping procedure, including fabrication and local annealing of the actuator, is provided. This thesis presents the experimental prototype actuator behaviour and compares it with simulations generated using the developed models.
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Clabby, Darragh. „Wave energy conversion at prototype and model scales“. Thesis, Queen's University Belfast, 2014. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.673795.
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The performance of a Wave Energy Converter (WEC) may be estimated using both physical and numerical modelling techniques. Since numerical models are often informed by, and validated against data obtained from physical models, it is important to assess the accuracy with which a prototype's behaviour is predicted by its physical model. This thesis makes such an assessment for the case of a pitching flap type WEC, by comparing the performance of Aquamarine Power's Oyster1 prototype device to that of a representative physical model. This comparison was informed by considering the device in terms of three sub-systems, namely: the flap; the incident waves; and the power take-off (PTO) system. Understanding the effects of characteristics associated with each of these sub-systems on the device's behaviour was pursued using both physical and numerical modelling techniques. As well as informing the comparison between the device's performance at each scale, the conclusions drawn from this work, particularly in relation to the modelling of sea conditions and PTO systems, are relevant to WEC modelling in general. Agreement between the device's behaviour at each scale was assessed by comparing measurements of the flap's angular position and velocity, and the power captured by the PTO. The velocity measured at prototype scale was 12% greater than that measured at model scale. The disagreement between velocity measurements directly affected agreement between power capture measurements, which were also 12% greater at prototype scale compared to model scale. Damage to the PTO cylinders meant that the device's performance was sub-optimal. Extrapolation of the comparison between the device's performance at each scale suggested that the power captured was 7% greater at prototype scale relative to model scale at magnitudes of power capture more representative of optimal performance.
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Jolibois, Alexandre. „A study on the acoustic performance of tramway low height noise barriers: gradient-based numerical optimization and experimental approaches ( Étude de la performance acoustique des écrans antibruit de faible hauteur pour le tramway : optimisation numérique par méthode de gradient et approches expérimentales)“. Thesis, Paris Est, 2013. http://www.theses.fr/2013PEST1116/document.
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Le bruit est devenu une nuisance importante en zone urbaine au point que selon l'Organisation Mondiale de la Santé, 40% de la population européenne est exposée à des niveaux de bruit excessifs, principalement dû aux transports terrestres. Il devient donc nécessaire de trouver de nouveaux moyens de lutter contre le bruit en zone urbaine. Dans ce travail, on étudie une solution possible à ce problème: un écran bas antibruit. Il s'agit d'un écran de hauteur inférieure à un mètre placé près d'une source, conçu pour réduire le niveau de bruit pour les piétons et les cyclistes à proximité. Ce type de protection est étudié numériquement et expérimentalement. Nous nous intéressons particulièrement aux écrans adaptés au bruit du tramway puisque dans ce cas les sources sont proches du sol et peuvent être atténuées efficacement. La forme ainsi que le traitement de surface de l'écran sont optimisés par une méthode de gradient couplée à une méthode 2D d'éléments finis de frontière. Les variables à optimiser sont les coordonnées de nœuds de contrôle et les paramètres servant à décrire l'impédance de surface. Les sensibilités sont calculées efficacement par la méthode de l'état adjoint. Les formes générées par l'algorithme d'optimisation sont assez irrégulières mais induisent une nette amélioration par rapport à des formes simples, d'au moins 5 dB (A). Il est également montré que l'utilisation de traitement absorbant du côté source de l'écran peut améliorer la performance sensiblement. Ce dernier point est confirmé par des mesures effectuées sur modèle réduit. De plus, un prototype à l'échelle 1 d'écran bas antibruit a été construit et testé en conditions réelles, le long d'une voie de tramway à Grenoble. Les mesures montrent que la protection réduit le niveau de 10 dB (A) pour un récepteur proche situé à hauteur d'oreilles. Ces résultats semblent confirmer l'applicabilité de ces protections pour réduire efficacement le bruit en zone urbaineNoise has become a main nuisance in urban areas to the point that according to the World Health Organization 40% of the European population is exposed to excessive noise levels, mainly due to ground transportation. There is therefore a need to find new ways to mitigate noise in urban areas. In this work, a possible device to achieve this goal is studied: a low-height noise barrier. It consists of a barrier typically less than one meter high placed close to a source, designed to decrease the noise level for nearby pedestrians and cyclists. This type of device is studied both numerically and experimentally. Tramway noise barriers are especially studied since the noise sources are in this case very close to the ground and can therefore be attenuated efficiently. The shape and the surface treatment of the barrier are optimized using a gradient-based method coupled to a 2D boundary element method (BEM). The optimization variables are the node coordinates of a control mesh and the parameters describing the surface impedance. Sensitivities are calculated efficiently using the adjoint state approach. Numerical results show that the shapes generated by the optimization algorithm tend to be quite irregular but provide a significant improvement of more than 5 dB (A) compared to simpler shapes. Utilizing an absorbing treatment on the source side of the barrier is shown to be efficient as well. This second point has been confirmed by scale model measurements. In addition, a full scale low height noise barrier prototype has been built and tested in situ close to a tramway track in Grenoble. Measurements show that the device provides more than 10 dB (A) of attenuation for a close receiver located at the typical height of human ears. These results therefore seem to confirm the applicability of such protections to efficiently decrease noise exposure in urban areas
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Mohammed, Abba-Gana. „Experimental comparison of brickwork behaviour at prototype and model scales“. Thesis, Cardiff University, 2006. http://orca.cf.ac.uk/56088/.
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A programme of masonry tests has been undertaken at prototype and model scales with a view to comparing their behaviour and strength under various conditions of loading. Characterisation tests were carried out to determine the principal behaviour of the units and mortar before the main programme of masonry test. The testing regime was in two parts: in the first category of tests compressive, shear, flexural, bond and diagonal tensile strength tests were carried out on prototype, half, fourth and sixth scale models. While in the second category of tests the effect of different joint thickness, increasing mortar strength and different sand gradings were tested on the compressive, shear, flexural, bond and diagonal tensile strengths of sixth scale model masonry. The size effect laws for quasi-brittle materials from fracture mechanics were also applied to the test data in order to find out their suitability to masonry model studies. The knowledge gained on the model scale behaviour of masonry was then applied to a prototype study involving the effect of eccentricity on the compressive strength of masonry as it relates to masonry arches. The sixth model scale was used for this study using four different eccentricities. On the whole, the model tests showed similar behaviour to the prototype. While there was no discernable scale effect in the shear, flexural, bond and diagonal tensile strength test, the compressive strength tests showed a noticeable scale effect. The parametric study at sixth scale also showed it is possible to use a sixth model to determine the effect of the increasing mortar strength and different grading of sands on masonry strength. However, the effect of increasing joint thickness was difficult to quantify. Indications from the size effect analysis of test data were also encouraging. The experimental data from the different tests were generally found to be in good agreement with the size effect laws of fracture mechanics. The application study was found to agree with the prototype investigation for low eccentricities but does not correspond well for higher eccentricities. Overall the results showed that it was possible to use model tests to provide masonry strength properties that could be used to determine the structural behaviour real life structures from numerical studies.
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Jolibois, Alexandre, und Alexandre Jolibois. „A study on the acoustic performance of tramway low-height noise barriers : gradient-based numerical optimization and experimental approaches“. Phd thesis, Université Paris-Est, 2013. http://pastel.archives-ouvertes.fr/pastel-00965168.
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Noise has become a main nuisance in urban areas to the point that according to the World Health Organization 40% of the European population is exposed to excessive noise levels, mainly due to ground transportation. There is therefore a need to find new ways to mitigate noise in urban areas. In this work, a possible device to achieve this goal is studied: a low-height noise barrier. It consists of a barrier typically less than one meter high placed close to a source, designed to decrease the noise level for nearby pedestrians and cyclists. This type of device is studied both numerically and experimentally. Tramway noise barriers are especially studied since the noise sources are in this case very close to the ground and can therefore be attenuated efficiently. The shape and the surface treatment of the barrier are optimized using a gradient-based method coupled to a 2D boundary element method (BEM). The optimization variables are the node coordinates of a control mesh and the parameters describing the surface impedance. Sensitivities are calculated efficiently using the adjoint state approach. Numerical results show that the shapes generated by the optimization algorithm tend to be quite irregular but provide a significant improvement of more than 5 dB (A) compared to simpler shapes. Utilizing an absorbing treatment on the source side of the barrier is shown to be efficient as well. This second point has been confirmed by scale model measurements. In addition, a full scale low height noise barrier prototype has been built and tested in situ close to a tramway track in Grenoble. Measurements show that the device provides more than 10 dB (A) of attenuation for a close receiver located at the typical height of human ears. These results therefore seem to confirm the applicability of such protections to efficiently decrease noise exposure in urban areas
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Meredith, James D. C. (James Douglas Charles). „Design, construction and testing of an ocean renewable energy storage scaled prototype“. Thesis, Massachusetts Institute of Technology, 2012. http://hdl.handle.net/1721.1/70437.
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Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 2012.Cataloged from PDF version of thesis.
Includes bibliographical references (p. 95-96).
The concept for a new form of pumped storage hydro is being developed within the Precision Engineering Research Group at MIT: the Ocean Renewable Energy Storage (ORES) project. Large, hollow concrete spheres are created, fitted with a reversible pump-turbine and deployed to the sea floor. Water is then allowed to flow through the turbine, into the sphere, to produce power and power is stored back in the device by running the turbine backwards as a pump and evacuating the sphere. The first prototype of that concept is presented here. A land-based system was designed, built and tested to demonstrate its ability to store energy and test the viability of the manufacturing methods planned. The device was successfully built and cycled, storing 2Wh of energy. The round-trip efficiency of the device was severely affected by the low efficiency of the scaled down rotating equipment. It was also found that casting a monolithic sphere is preferable to assembling multiple pieces and that the interior of the sphere should be maintained at atmospheric pressure via a vent line.
by James D. C. Meredith.
S.M.
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Šlajchrt, Zbyněk. „Object Morphology—A Protean Generalization of Object-Oriented Paradigm“. Doctoral thesis, Vysoká škola ekonomická v Praze, 2010. http://www.nusl.cz/ntk/nusl-264276.
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Modeling protean objects, i.e. objects adapting their structure and behavior dynamically with respect to a changeable environment, is often challenging in traditional object-oriented languages. According to the author, the root cause of this problem lies in the class-based conceptual framework embedded in the foundation of the object-oriented para-digm. The proposed paradigm Object Morphology (OM) is greatly influenced by prototype theory developed in the field of cognitive psychology. OM abandons the notion of class and suggests, instead, that the abstractions of protean objects should be established through the construction of morph models describing the possible forms of those objects. This the-sis defines the theoretical foundations of OM, which is further used to specify the elements of prototypical object-oriented analysis. An important part of this work is also a proof-of-concept implementation of an OM framework in Scala.
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Tricard, Thibault. „Procedural noises for the design of small-scale structures in Additive Manufacturing“. Electronic Thesis or Diss., Université de Lorraine, 2022. http://www.theses.fr/2022LORR0065.
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La démocratisation de la fabrication additive a suscité un regain d'intérêt pour ses applications potentielles. Parmi celles-ci, la possibilité d'imprimer des structures à petite échelle est particulièrement prometteuse. La géométrie des structures internes à petite échelle influence directement les propriétés physiques des pièces finales. Ainsi, la découverte de nouvelles structures à petite échelle produisant des propriétés cibles spécifiques élargit les possibilités offertes aux utilisateurs de la fabrication additive, ce qui ouvre la voie à de nouvelles applications potentielles en soft-robotique, pour la conception de prothèses et d'orthèses, et pour l'ingénierie mécanique en général. Toutefois, pour être utiles, ces structures à petite échelle doivent permettre de contrôler les propriétés qu'elles déclenchent - et de les faire varier dans l'espace- afin d'adapter leur comportement à l'intention de l'utilisateur. Il est intéressant de noter que ce type de contrôle spatial des propriétés a été largement étudié en informatique graphique, en particulier pour la synthèse de textures. L'objectif de cette thèse est de permettre le même type de contrôle spatial que celui obtenu par les méthodes de synthèse de textures, pour la synthèse de structures à petite échelle dans la fabrication additive. En particulier, je me suis concentré sur la définition de structures à petite échelle fortement orientées. Celles-ci déclenchent des propriétés extrêmement anisotropes dans les pièces, un type de comportement qui n'a pas été approfondi dans les travaux antérieurs. Pour y parvenir, j'ai proposé de revisiter les formulations procédurales développées pour la synthèse de textures en informatique graphique, où chaque sous-partie d'un motif peut être calculée indépendamment, en suivant uniquement les informations locales. J'ai appliqué avec succès cette approche à la génération de structures complexes et orientées à petite échelle dans de grands volumes. Ma première contribution est une nouvelle approche pour synthétiser efficacement des motifs oscillants fortement contrastés, qui permet de suivre de près les champs de propriétés tels que l'orientation et la densité tout en étant calculés localement. J'ai démontré cette approche pour des applications de placage de textures ainsi que pour la synthèse de motifs fortement orientés, fortement orientées, anisotropes et multi-matériaux à petite échelle. Cette première méthode génère des motifs qui présentent des défauts locaux,et par conséquent, ma deuxième contribution a étendu ce travail pour formuler une technique de régularisation efficace et peu coûteuse qui rectifie les oscillations. Cela a conduit à la synthèse de structures autoportantes librement orientables qui peuvent être utilisées pour produire des déformations programmées dans des objets imprimés en 3D. Ma troisième contribution explore comment utiliser une approche similaire pour définir des trajectoires dans des pièces imprimées en 3D entièrement remplies, sous des objectifs d'orientation. En ajustant la phase des oscillations, nous sommes en mesure de rompre les alignements spatiaux le long de la direction de construction qui, autrement, entraîneraient des faiblesses locales dans les pièces produitesThe democratization of AM has sparked a renewed interest in its potential applications.Among these, the ability to print small-scale structures is particularly promising:The geometry of internal small-scales structures directly influences the physical properties of the final parts.Thus, finding novel small-scales structures producing specific target properties expands the possibilities offered to additive manufacturing users,unlocking new potential applications in soft-robotics, for the design of prosthetics and orthoses, and for mechanical engineering at large.However, to be helpful in the wild, these small-scale structures have to expose controls over the properties they trigger --and allow their variation in space -- so as to adapt their behavior to the user's intent.Interestingly, this type of spatial control over properties has been extensively studied in Computer Graphics,in particular for texture synthesis.The objective of this thesis is to enable the same type of spatial control that is achieved by texture synthesis methods,for the synthesis of small-scale structures in Additive Manufacturing.In particular, I focused on defining strongly oriented small-scale structures.These trigger extremely anisotropic properties within the parts, a type of behavior that has not been extensively covered in prior works.To achieve this, I proposed to revisit the procedural formulations developed for texture synthesis in Computer Graphics,where each subpart of a pattern can be computed independently, only following local information.I successfully applied this approach to the generation of complex, oriented small-scale structures in large volumes.My first contribution is a novel approach for efficiently synthesizing highly contrasted oscillating patterns, that allows to closely follow property fields such as orientation and density while still being computed locally.I demonstrated this approach for texturing applications as well as for the synthesis of strongly oriented, anisotropic multi-material small-scale structures. This first method generates patterns that exhibit local defects, and therefore my second contribution extended this work to formulate a low-cost, efficient regularization technique that rectifies the oscillations.This led to the synthesis of freely orientable, self-supporting structures that can be used to trigger programmed deformations in 3D printed objects.My third contribution explores how to use a similar approach to define trajectories in fully filled 3D printed parts, under orientation objectives.By adjusting the phase of the oscillations, we are able to break the spatial alignments along the build direction that would otherwise result in local weaknesses in the produced parts
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Amarir, Amine. „Pre-assessment of the Impact of Design Challenge Fabrication Modality on Engineering Self-Efficacy“. Thesis, Virginia Tech, 2021. http://hdl.handle.net/10919/103906.
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The introduction of project-based learning into university engineering programs has been shown to positively benefit students that prefer a hands-on experience and give future employers assurance that recent graduates have the tools to handle real-world problems as opposed to theoretical situations. Enhancing the engineering self-efficacy of students, recent graduates and seasoned engineers is made possible through the solution of complex, open-ended problems typically found in engineering design. A high engineering self-efficacy, in turn, positively reflects a person's perception of their complex problem-solving capacity which is critical throughout the design process. The decision to either work virtually with a team or onsite with group members nearby may also further influence self-efficacy and, ultimately, the designer's success. This raises the question explored in this study: Will a design challenge impact engineering self-efficacy equally for online and in-person participants? Two groups engaged in a design challenge to develop a mechanism meant for drone applications, where one group designed and tested their solution in-person, while the other group sent design plans to a third-party for fabrication and testing. Participants filled out a prototype engineering self-efficacy scale before and after the challenge, revealing a significant difference between these two modalities. The small sample size is noted as the cause for inaccuracies and surprising findings. Guidelines for methodology implementation in a larger scale study are included.Master of Science
In project-based learning courses, students work in groups to make a prototype or other solution to a stated problem, which are helpful for building student confidence in problem-solving, critical thinking and, especially, engineering skills. This confidence translates to believing that carrying out a specific task will lead to success with little-to-no feelings of fear or failure. This generally describes "self-efficacy," and it can apply to any profession. Traditionally, hands-on projects are done in person, where an exchange of ideas is clear and any problems can be handled immediately. However, with schools closed due to the COVID-19 pandemic, these courses had to shift online, leading some to believe that students would not receive the same level and quality of engineering education. Online learning has been around for over 30 years and studies show that students learn just as much, if not more and better, online than sitting in a classroom. Can the same be said for taking part in an engineering project over the internet? Two groups designed a prototype drone attachment, where members of one group worked side-by-side to build and test their solution, while members of the other group worked online and sent files and assembly instructions to a third party. Each participant also filled out a questionnaire before and after the challenge to track their engineering self-efficacy. The limited data led to the conclusion that there is a noticeable difference between the two project completion methods, most likely caused by a low number of participants. The lessons learned from this study were used to create guidelines for a larger-scale study.
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Di, Fabrizio Vincenzo. „Modellazione e analisi non lineare del degrado artificiale di un prototipo di edificio in muratura in scala reale“. Master's thesis, Alma Mater Studiorum - Università di Bologna, 2021.
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La tesi pone l’attenzione sulla modellazione di un edificio in muratura da sottoporre a prove di laboratorio. In particolare, sono state eseguite analisi modali e non lineari per determinare l’influenza sugli elementi in muratura di alcune forme di degrado imposte, quali sovraccarichi, grado di ammorsamento della muratura, assenza di tiranti e cedimento differenziale della fondazione. I risultati ottenuti attraverso le analisi modali mostrano una notevole riduzione della rigidezza del sistema. Il cedimento differenziale imposto porta ad una concentrazione dello stato tensionale nelle fasce di piano in prossimità delle aperture.
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Romagnoli, Roberto, und ROBERTO ROMAGNOLI. „Aerogeneratori eolici ad asse verticale: analisi numerica, verifica sperimentale e messa a punto di un campo di prova per prototipi full-scale“. Doctoral thesis, Università Politecnica delle Marche, 2013. http://hdl.handle.net/11566/242724.
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Il lavoro ha avuto come oggetto l'indagine sui rotori a resistenza
ad asse verticale. L'approccio seguito ha coinvolto sia l'evidenza
sperimentale che la modellazione numerica. I due approcci sono
complementari: il modello numerico, mettendo alla luce le cause
fluidodinamiche del meccanismo di conversione energetica, conduce
alla definizione del rotore. I test sperimentali si sono occupati di
elementi esterni al rotore e difficilmente ripetibili nel modello
numerico. Per questo gli obiettivi si sono differenziati per i due
approcci.
Nei test sperimentali svolti in galleria del vento si è voluto
determinare le configurazioni in grado di migliorare le prestazioni
di un dato rotore. Nelle analisi numeriche si è studiato il campo di
moto e quindi ipotizzate nuove geometrie rotoriche. Il rotore di
riferimento per entrambi gli approcci è un Savonius “classico” a pale
semicircolari dritte, con schermi di estremità per riprodurre la
bidimensionalità del modello numerico.
Le prestazioni sono valutate in curve CP-lambda; il primo è il
coefficiente di Potenza, il secondo è il rapporto tra la velocità di
rotazione e quella del flusso incidente.
La configurazione sperimentale che risulta migliore è quella che
adotta contemporaneamente schermi, convogliatore e deflettore. Il CP
massimo vale 0.3, ossia +25% rispetto al riferimento.
I risultati CFD hanno evidenziato due geometrie: il Savonius
classico senza albero centrale e un modello definito “a profilo
invertito”. Per entrambi il CP massimo vale circa 0.29 senza
l’utilizzo di appendici esterne.
Infine è stata realizzata una postazione di prova all'esterno per
test su modelli full-scale di sistemi alimentati da fonte eolica.
Essa è composta da una piazzola per i prototipi, una torre
meteorologica di 10 metri e una postazione Sodar-Rass.
E’ emerso che il sito è caratterizzato da brezze locali per gran
parte dell'anno e una direzione prevalente di 330 gradi.
La postazione esterna è funzionante e attualmente un primo
prototipo di lampione eolico è oggetto di studi sperimentali.This work is focused on drag driven vertical axis wind turbines. The study involved both experimental measurements and numerical analyses. The two methods are complementary: CFD analyses allow us gain an insight into the rotor's fluid dynamics that lead to energy production. The experimental measurements allow us to evaluate the elements that are difficult to put inside a numerical model. For this reason the two approaches have different aims. The experiments have been performed in a closed circuit wind tunnel. They investigate the configurations that could improve the performance of a given rotor. The numerical analyses were conducted to improve the flow field knowledge and to design new rotor's geometries. Both approaches started from a classic Savonius rotor equipped with semi-circular straight blades S-shaped, with end plates to replicate the two-dimensional effects of the numerical model. The performance were evaluated with CP-lambda plots, where CP is the Power coefficient and lambda is the rotation velocity versus wind speed ratio. The best experimental configuration correspond to the reference rotor with conveyor and deflector: its CP max was 0.3, with +25% gain with the respect of the reference rotor. CFD analyses have shown two best geometries: the classical Savonius without the central shaft and a new geometry defined as “reversed profile”. They have both a CP maximum around 0.29 without any external appendices. Finally an external test station was build up to perform experimental measurements on full-scale small wind turbines models. It is composed by a test station for prototypes, a 10 meters meteorological mast and a Sodar-Rass station. It was found that the site is characterized by local breezes blowing most of the year and a prevailing direction of 330 degrees. The external station is operational and an urban lamppost prototype supplied by wind energy and is currently the subject of experimental studies.
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Sahare, Swapnil Ashok. „Enhancing the Photovoltaic Efficiency of a Bulk Heterojunction Organic Solar Cell“. TopSCHOLAR®, 2016. http://digitalcommons.wku.edu/theses/1609.
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Active layer morphology of polymer-based solar cells plays an important role in improving power conversion efficiency (PCE). In this thesis, the focus is to improve the device efficiency of polymer-based solar cells. In the first objective, active layer morphology of polymer-solar cells was optimized though a novel solvent annealing technique. The second objective was to explore the possibility of replacing the highly sensitive aluminum cathode layer with a low-cost and stable alternative, copper metal. Large scale manufacturing of these solar cells is also explored using roll-to-roll printing techniques.
Poly (3-hexylthiophene) (P3HT) and phenyl-C61-butyric acid methyl (PCBM) were used as the active layer blend for fabricating the solar cell devices using bulk heterojunction (BHJ), which is a blend of a donor polymer and an acceptor material. Blends of the donor polymer, P3HT and acceptor, PCBM were cast using spin coating and the resulting active layers were solvent annealed with dichlorobenzene in an inert atmosphere. Solvent annealed devices showed improved morphology with nano-phase segregation revealed by atomic force microscopy (AFM) analysis. The roughness of the active layer was found to be 6.5 nm. The nano-phase segregation was attributed to PCBM clusters and P3HT domains being arranged under the solvent annealing conditions. These test devices showed PCE up to 9.2 % with current density of 32.32 mA/cm2, which is the highest PCE reported to date for a P3HT-PCBM based system.
Copper was deposited instead of the traditional aluminum for device fabrication. We were able to achieve similar PCEs with copper-based devices. Conductivity measurements were done on thermally deposited copper films using the two-probe method. Further, for these two configurations, PCE and other photovoltaic parameters were compared.
Finally, we studied new techniques of large scale fabrication such as ultrasonic spray coating, screen-printing, and intense pulse light sintering, using the facilities at the Conn Center for Renewable Energy Research at the University of Louisville. In this study, prototype devices were fabricated on flexible ITO coated plastics. Sintering greatly improved the conductivity of the copper nano-ink cathode layer. We will explore this technique’s application to large-scale fabrication of solar cell devices in the future work.
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Napoli, Valeria Rossella. „Dimensionamento ed efficienza del convertitore di energia ondosa SEAWAVE SLOT-CONE GENERATOR. Studio per una installazione a scala di prototipo in Italia“. Master's thesis, Alma Mater Studiorum - Università di Bologna, 2009. http://amslaurea.unibo.it/314/.
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DANIELSSON, ELLEN, und CHRISTOPHER LEKSTRÖM. „Investigation and Optimization of Small-Scale Fecal Management : As a product from dry toilet solutions in off-grid Swedish holiday homes“. Thesis, KTH, Skolan för industriell teknik och management (ITM), 2021. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-299334.
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In off-grid holiday homes, alternative toilet solutions are needed. There is a wide range of dry toilet systems, where urine-diverting systems and incineration toilets are common solutions. Urine-diverting dry toilets require that users need to manage generated fecal fractions. This is often done by private composting or through municipal latrine bucket pick-ups. In this project, fecal management for holiday homes in Sweden is examined from three perspectives by (1) studying the biological phenomenon with composting and how a compost should be managed to generate rich humus, whilst minimizing greenhouse gas emissions associated with the act of composting, (2) examine current user experiences associated with latrine compost management, and (3) map out current latrine management systems, including laws and regulations. The goal was to develop a user-friendly concept for fecal management for urine-diverting toilets, based on this research. The project was carried out in collaboration with Harvest Moon, a company focused on the development of innovative and refined dry toilet systems. The project was initiated with a literature review, the examination of current fecal management systems, and interviews with composting experts and researchers. The background research showed that there is no such thing as perfect compost management since it depends on what end goals the users have. Research also showed that frequently turning the pile, increases ammonia (NH3) emissions, but reduces methane (CH4) formation. Furthermore, biochar can be added as a bulking agent to aerate the compost mass, and aid the hygienization process of such a mass, since it binds e.g., hormones. Regarding composting methods, a static passively aerated compost is not the fastest process but has the least compost mass reduction, which is desired when using it as a soil enhancer. In addition, it requires the least management. This method was therefore chosen for further development. Furthermore, since temperature and moisture are easily measured with sensors, it was deemed interesting to implement such sensors in a final concept, to alleviate management for the user. To assure that the final concept would reflect user needs and wishes, a phase of user studies was then initiated. The studies showed that users generally see latrine compost more as something to take care of, rather than as a resource, and therefore have no interest in using composted humus. The research also showed that because many municipalities require 2-year storage of the material in the composter, users experienced scheduling issues, which ultimately led to an inefficien composting system. The third perspective that was investigated, was the management systems of today and how they are regulated by laws. Each municipality has its own requirements on how latrine composts should be managed. These requirements are based on the Environmental Code, as well as Naturvårdsverket’s recommendation for the implementation of the law. Apart from the compilation of these regulations, this investigation showed that pyrolysis, as well as the centralization of hygienized feces, could be future alternatives to latrine composting and latrine pickup. But due to the short Time-to-Market, and the project's limited time scope, product development towards system innovation was deemed unrealistic within this project. Insights from these three perspectives created a framework for the concept development phase, which was finalized with building a full-scale functional prototype. During detailed design, the concept was further developed in CAD. The final concept presented in this project is a modular, user-friendly latrine compost that can be adapted to follow different municipal regulations. It has an inner mesh that aerates the compost mass to reduce methane gas formation. The mesh is constructed with hexagonal perforated acid-proof steel. The composter has a push latch mechanism on the lid together with two gas struts, which makes it easy to open since the user only needs to push the lid once, for it to open. Temperature and moisture sensors make it easier for the user to manage their compost correctly, and a front door allows for ergonomic emptying of the finished compost humus. Future development to reduce production costs, simplify the construction, continue the CAD model development, find suitable sensors, develop product instructions as well as perform user tests with the physical prototype should be further investigated.I fritidshus som saknar kommunalt avlopp behövs alternativa toalettlösningar. Det finns en rad olika torra toalettsystem, där urinsorterande och förbränningstoaletter är vanliga lösningar. Urinsorterande torrtoaletter kräver att användaren själv tar hand om genererade fekalier. Detta görs genom antingen privat latrinkompostering eller kommunal hämtning av latrin. I detta projekt undersöks fekaliehantering för fritidshus i Sverige från tre perspektiv genom att (1) studera biologiska fenomen i en kompost och hur en kompost ska hanteras för att få en rik humus, samt minimera växthusgasutsläpp som bildas vid just kompostering, (2) undersöka användarupplevelsen vid hantering av latrinkomposter idag, samt (3) kartlägga nuvarande system för latrinhantering, inklusive rådande lagar och förordningar. Målet med projektet var att utveckla ett användarvänligt koncept för fekaliehantering från urinsorterande toaletter, baserat på denna forskning. Projektet genomfördes i samarbete med Harvest Moon, ett företag som arbetar med att utveckla innovativa och estetiskt tilltalande torrtoalettsystem. Projektet inleddes med att studera litteratur, undersöka befintliga fekaliehanteringssystem, samt att intervjua komposteringsexperter och forskare inom området. Efter denna bakgrundsforskning kunde slutsatsen dras att det inte finns en perfekt komposthantering, då det beror på de mål som användaren har. Forskningen visade också att ju mer man vände kompostmassan, desto mer ökade utsläppen av ammoniak (NH3), dock minskade bildningen av metan (CH4). En annan insikt var att biokol kan tillsättas för att lufta, samt hjälpa till att hygienisera kompostmassan, då det binder till sig till exempel hormonrester. Gällande komposteringsmetoder så är en statisk passivt luftad kompost inte den snabbaste processen, men den leder till minst kompostreduktionen, vilket är bra om målet är att använda det komposterade materialet som jordförbättrare. Dessutom kräver det den minsta hanteringen av användaren. Denna metod valdes därför för vidareutveckling av slutkoncept. Slutligen, eftersom både temperatur och fukt lätt går att mäta med sensorer, så ansågs det intressant att implementera dessa typer av sensorer i ett slutkoncept i och med att det skulle kunna underlätta hanteringsprocessen för användaren. För att säkerställa att det slutliga konceptet skulle återspegla vad användarna behöver och önskar, inleddes sedan en fas av användarstudier. Användarstudierna visade att användare i allmänhet ser latrinkompost mer som något de måste ta hand om, än som en resurs, och har därmed inget intresse av att ta vara på det materialet som har komposterats. Studierna visade också att på grund av att många kommuner kräver två års lagring av materialet i fekaliekomposten, upplevde användare svårigheter med att få till en bra rutin kring hanteringen, vilket bidrog till att hela latrinhanteringssystemet fungerade sämre. Det tredje perspektivet som undersöktes inom projektet var hur systemen för latrinhantering ser ut idag, samt hur och av vilka lagar de regleras. Varje kommun har egna krav på hur en latrinkompost ska hanteras. Dessa krav är baserade på Miljöbalken, liksom Naturvårdsverkets rekommendationer gällande den praktiska implementeringen av Miljöbalken. Utöver sammanställningen av dessa regelverk visade studien att pyrolys, alternativt centralisering av hygieniserade fekalier, skulle kunna vara framtida alternativ till kompostering eller kommunal hämtning av latrin. Men på grund av den korta Time-to-Market för denna produkt, samt projektets begränsade tidsram ansågs produktutveckling mot systeminnovation vara orealistisk inom detta projekt. Insikter från dessa tre perspektiv bildade ett ramverk för konceptutvecklingsfasen, som avslutades med byggandet av en fullskalig funktionsprototyp. Under detaljutvecklingen fortsattes utvecklingen av konceptet i CAD. Det slutgiltiga konceptet som presenteras i projektet är en modulär, användarvänlig latrinkompost som går att anpassa till att följa olika kommunala regler. Den har en inre struktur som luftar kompostmaterialet för att minska bildandet av metangas. Strukturen består av hexagonalt perforerat syrafast stål. Komposten har en push latch mekanism på locket tillsammans med två gasfjädrar, vilket gör det enkelt att öppna eftersom användaren endast behöver trycka locket för att det ska öppnas. Temperatur- och fuktsensorer gör det lättare för användaren att hantera sin kompost korrekt, och en främre dörr möjliggör ergonomisk tömning av färdigt kompostmaterial. Framtida utveckling för att minska produktionskostnaderna, förenkla konstruktionen, vidareutveckla CAD-modellen, hitta lämpliga sensorer, utveckla användarinstruktioner, samt genomförandet av användartester med funktionsprototypen bör vidare undersökas.
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Napoli, Maria Teresa. „Analisi del funzionamento e dell'impatto ambientale di un convertitore di energia ondosa di tipo Wave Activated Body. Studio per l'installazione a scala di prototipo a Nissum Bredning“. Master's thesis, Alma Mater Studiorum - Università di Bologna, 2009. http://amslaurea.unibo.it/301/.
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34
Willschütz, H. G. „Thermomechanische Modellierung eines Reaktordruckbehälters in der Spätphase eines Kernschmelzunfalls“. Forschungszentrum Dresden, 2010. http://nbn-resolving.de/urn:nbn:de:bsz:d120-qucosa-28520.
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Considering the late in-vessel phase of an unlikely core melt down scenario in a light water reactor (LWR) with the formation of a corium pool in the lower head of the re-actor pressure vessel (RPV) the possible failure modes of the RPV and the time to failure have to be investigated to assess the possible loadings on the containment. In this work, an integral model was developed to describe the processes in the lower plenum of the RPV. Two principal model domains have to be distinguished: The temperature field within the melt and RPV is calculated with a thermodynamic model, while a mechanical model is used for the structural analysis of the vessel wall. In the introducing chapters a description is given of the considered accident scenario and the relevant analytical, experimental, and numerical investigations are discussed which were performed worldwide during the last three decades. Following, the occur-ring physical phenomena are analysed and the scaling differences are evaluated between the FOREVER-experiments and a prototypical scenario. The thermodynamic and the mechanical model can be coupled recursively to take into account the mutual influence. This approach not only allows to consider the tem-perature dependence of the material parameters and the thermally induced stress in the mechanical model, it also takes into account the response of the temperature field itself upon the changing vessel geometry. New approaches are applied in this work for the simulation of creep and damage. Using a creep data base, the application of single creep laws could be avoided which is especially advantageous if large temperature, stress, and strain ranges have to be covered. Based on experimental investigations, the creep data base has been de-veloped for an RPV-steel and has been validated against creep tests with different scalings and geometries. It can be stated, that the coupled model is able to exactly describe and predict the vessel deformation in the scaled integral FOREVER-tests. There are uncertainties concerning the time to failure which are related to inexactly known material parame-ters and boundary conditions. The main results of this work can be summarised as follows: Due to the thermody-namic behaviour of the large melt pool with internal heat sources, the upper third of the lower RPV head is exposed to the highest thermo-mechanical loads. This region is called hot focus. Contrary to that, the pole part of the lower head has a higher strength and therefore relocates almost vertically downwards under the combined thermal, weight and internal pressure load of the RPV. On the one hand, it will be possible by external flooding to retain the corium within the RPV even at increased pressures and even in reactors with high power (as e.g. KONVOI). On the other hand, there is no chance for melt retention in the considered scenario if neither internal nor external flooding of the RPV can be achieved. Two patents have been derived from the gained insights. Both are related to pas-sively working devices for accident mitigation: The first one is a support of the RPV lower head pole part. It reduces the maximum mechanical load in the highly stressed area of the hot focus. In this way, it can prevent failure or at least extend the time to failure of the vessel. The second device implements a passive accident mitigation measure by making use of the downward movement of the lower head. Through this, a valve or a flap can be opened to flood the reactor pit with water from a storage res-ervoir located at a higher position in the reactor building. With regard to future plant designs it can be stated - differing from former presump-tions - that an In-Vessel-Retention (IVR) of a molten core is possible within the reac-tor pressure vessel even for reactors with higher power.
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Willschütz, H. G. „Thermomechanische Modellierung eines Reaktordruckbehälters in der Spätphase eines Kernschmelzunfalls“. Forschungszentrum Rossendorf, 2006. https://hzdr.qucosa.de/id/qucosa%3A21677.
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Considering the late in-vessel phase of an unlikely core melt down scenario in a light water reactor (LWR) with the formation of a corium pool in the lower head of the re-actor pressure vessel (RPV) the possible failure modes of the RPV and the time to failure have to be investigated to assess the possible loadings on the containment. In this work, an integral model was developed to describe the processes in the lower plenum of the RPV. Two principal model domains have to be distinguished: The temperature field within the melt and RPV is calculated with a thermodynamic model, while a mechanical model is used for the structural analysis of the vessel wall. In the introducing chapters a description is given of the considered accident scenario and the relevant analytical, experimental, and numerical investigations are discussed which were performed worldwide during the last three decades. Following, the occur-ring physical phenomena are analysed and the scaling differences are evaluated between the FOREVER-experiments and a prototypical scenario. The thermodynamic and the mechanical model can be coupled recursively to take into account the mutual influence. This approach not only allows to consider the tem-perature dependence of the material parameters and the thermally induced stress in the mechanical model, it also takes into account the response of the temperature field itself upon the changing vessel geometry. New approaches are applied in this work for the simulation of creep and damage. Using a creep data base, the application of single creep laws could be avoided which is especially advantageous if large temperature, stress, and strain ranges have to be covered. Based on experimental investigations, the creep data base has been de-veloped for an RPV-steel and has been validated against creep tests with different scalings and geometries. It can be stated, that the coupled model is able to exactly describe and predict the vessel deformation in the scaled integral FOREVER-tests. There are uncertainties concerning the time to failure which are related to inexactly known material parame-ters and boundary conditions. The main results of this work can be summarised as follows: Due to the thermody-namic behaviour of the large melt pool with internal heat sources, the upper third of the lower RPV head is exposed to the highest thermo-mechanical loads. This region is called hot focus. Contrary to that, the pole part of the lower head has a higher strength and therefore relocates almost vertically downwards under the combined thermal, weight and internal pressure load of the RPV. On the one hand, it will be possible by external flooding to retain the corium within the RPV even at increased pressures and even in reactors with high power (as e.g. KONVOI). On the other hand, there is no chance for melt retention in the considered scenario if neither internal nor external flooding of the RPV can be achieved. Two patents have been derived from the gained insights. Both are related to pas-sively working devices for accident mitigation: The first one is a support of the RPV lower head pole part. It reduces the maximum mechanical load in the highly stressed area of the hot focus. In this way, it can prevent failure or at least extend the time to failure of the vessel. The second device implements a passive accident mitigation measure by making use of the downward movement of the lower head. Through this, a valve or a flap can be opened to flood the reactor pit with water from a storage res-ervoir located at a higher position in the reactor building. With regard to future plant designs it can be stated - differing from former presump-tions - that an In-Vessel-Retention (IVR) of a molten core is possible within the reac-tor pressure vessel even for reactors with higher power.
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Archez, Julien. „Formulations de composites à base de liants basse température type géopolymère à base d'argilite et de différents renforts : réalisation d'une pièce par fabrication additive“. Thesis, Limoges, 2020. http://aurore.unilim.fr/theses/nxfile/default/bd491a52-1855-4e0d-9b5b-6284748bb761/blobholder:0/2020LIMO0059_arch.pdf.
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Ce travail s’inscrit dans le cadre du projet Cigéo (Centre industriel de stockage géologique de déchets radioactifs) et étudie des voies d’optimisation pour les chemisages des alvéoles de stockage des déchets radioactifs de haute activité (HA). Des matériaux composites à matrice et renforts inorganiques sont une des voies d’innovation envisagées en alternative aux matériaux métalliques pour la réalisation du chemisage. L’utilisation de matériaux de type géopolymères renforcés par des éléments non organiques pourrait répondre aux critères souhaités. L’ajout de wollastonite et de fibres de verre à une matrice géopolymère a tout d’abord permis de contrôler la viscosité et de l’adapter à une mise en forme par coulage ou par fabrication additive tout en assurant une tenue mécanique satisfaisante du matériau consolidé. Des résistances mécaniques en compression et en flexion allant respectivement jusqu’à 101 MPa et 20 MPa ont pu être obtenues. Pour tester la solution extrudée à l’échelle ½, un système d’impression 3D a ensuite été développé. Une tête d’extrusion spécifique a été conçue et intégrée à une cellule robotique 6 axes. Le contrôle et l’identification des paramètres d’impression et des paramètres matériaux ont finalement permis la maitrise du pilotage du procédé et l’impression de structures en composite géopolymère à l’échelle ½ (ɸ = 35 cm)This work is part of the Cigéo project (geological industrial disposal for radioactive wastes) and focuses on studying alternative materials for the elaboration of the lining of the high-level radioactive waste storage cells. Composites materials with inorganic matrix and reinforcements are one of the innovations being considered as an alternative to replace metallic materials in the lining. The use of geopolymers reinforced with inorganic elements could meet the desired specifications. The insertion of wollastonite and glass fibers to a geopolymer matrix allowed to control viscosity suitable for shaping by casting and additive manufacturing while ensuring the mechanical strength of the consolidated material. This allows obtaining flexural and compressive strengths going up to 101 MPa and 20 MPa, respectively. To shape the extruded solution at a half scale, a 3D printing system was then developed. A specific extrusion head has been designed and integrated into a 6-axis robotic cell. The control and identification of printing and materials parameters make it possible to control the process and to print geopolymer composite structures at half scale (ɸ = 35 cm)
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Jaber, Jana. „Application de la fabrication additive à la modélisation physique des joints et des massifs rocheux, par approches expérimentales et numériques“. Electronic Thesis or Diss., Université de Lorraine, 2020. http://www.theses.fr/2020LORR0071.
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Cette thèse présente une étude de l’application de la fabrication additive (connue sous le nom d’impression 3D) à la mécanique des roches. Elle s’inscrit dans le cadre d’un projet plus large visant à construire un modèle physique de 2m3 d’un massif rocheux explicitement discontinu, dont le comportement est contrôlé principalement par les discontinuités. La technique de fabrication additive adoptée est le frittage laser (SLS), le matériau utilisé est un polymère : le polyamide 12 (PA12). Dans un premier temps des joints artificiels construits par SLS sont testés sous essais de cisaillement à contrainte normale constante. Deux familles de discontinuités sont étudiées. La première est formée par des joints à géométrie simplifiée (joints planaires ou en dents de scies) ayant une ouverture de 0,4mm et contenant des ponts rocheux. Les résultats montrent que cette technique de fabrication des joints en PA12 permet d’obtenir un comportement global similaire à celui des joints rocheux naturels, avec une cohésion pilotée par les ponts rocheux, et un angle de frottement dépendant de l’angle des aspérités. La deuxième famille est constituée de joints ayant des rugosités plus réalistes, auxquelles on peut attribuer une valeur de JRC, communément utilisée pour décrire les joints naturels. Cette configuration permet elle aussi de reproduire un comportement global équivalent à celui des joints naturels, avec une mobilisation des aspérités primaires et secondaires des surfaces. Les résultats obtenus sont comparés au critère de rupture de Barton-Bandis. Cette étude expérimentale est complétée par une modélisation numérique sous le logiciel UDEC, dans le but d’étudier la capacité des modèles existants à reproduire le comportement des joints artificiels obtenu expérimentalement, et de calibrer numériquement les paramètres mécaniques utilisés dans la modélisation pour représenter les essais expérimentaux. Dans un second temps, des éprouvettes cylindriques (16 x 32 cm) contenant deux ou huit discontinuités à géométrie simplifiée (planaire + ponts rocheux) sont fabriquées et testées sous compression uni-axiale. Il s’agit d’une première tentative d’un modèle réduit explicitement discontinu et contenant des joints ayant un comportement mécanique contrôlé. Les résultats permettent de mettre l’accent sur l’influence des discontinuités sur le comportement global d’un massif rocheux. Ces essais sont comparés à une modélisation numérique sous 3EDC. Finalement, et afin d’étudier l’applicabilité de cette technique à la modélisation physique, les lois de similitudes sont appliquées aux résultats obtenus dans les parties précédentes. Il en ressort qu’il est possible d’utiliser la SLS et le PA12 en modélisation physique des massifs rocheux, jusqu’un facteur d’échelle sur les dimensions métriques de 1/25This thesis presents a study of the application of additive manufacturing (known as 3D printing) to rock mechanics. It is part of a larger project aimed at building a 2m3 physical model of an explicit discontinuous rock mass, whose behaviour is mainly controlled by discontinuities. The 3DP technology adopted in this work is selective laser sintering, and the material is Polyamide 12. First, we present the experimental results of the mechanical characterization of artificial rock joints constructed by 3DP. Two joint families are tested. The first is characterized by a fixed aperture (0,4mm), a simplified geometry (planar or sawtooth), and containing rock bridges. The mechanical characterization shows that these joints exhibit a mechanical behavior similar to that of natural rock joints under shear tests, with a cohesion driven by the rock bridges, and a friction angle which depends on the angle of the asperities. The second family consists of joints with more realistic roughnesses, to which a JRC value, commonly used to describe natural joints, can be assigned. Again, experimental results show the potential of artificial joints to reproduce the mechanical behavior of natural joints, and to respect the Barton-Bandis criterion. Experimental studies are coupled with numerical modeling, using the UDEC software, to define the appropriate model that reproduces the experimental results, and to calibrate the mechanical parameters of both joints type. After defining different artificial joints with controlled parameters, cylindrical samples (16 x 32 cm) containing two and eight planar discontinuities with rock bridges are printed and tested under uni-axial compression. This is a first attempt at an explicitly discontinuous physical model containing joints with controlled mechanical behaviour. The mechanical behavior of these samples highlights the influence of discontinuities in controlling the global behavior and resistance of rock masses. The results are then compared to a numerical modeling under 3EDC. Finally, scaling laws are applied to the previous results. The application of scale factors to the experimental results shows the possibility of representing natural rock mass and rock joints with artificial 3DP joints (SLS technique) up to a scale factor on metric dimensions of 1/25
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Andrade, Bruno Miguel Costa de. „PLACM - Prototype Large-Scale Accessibility Compliance Monitoring“. Master's thesis, 2020. http://hdl.handle.net/10451/47988.
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Tese de mestrado, Engenharia Informática (Interação e Conhecimento) Universidade de Lisboa, Faculdade de Ciências, 2020Com o aumento da modernização da sociedade, a Internet já se transformou numa ferramenta utilizada todos os dias por milhões de pessoas. Mas com esta magnitude, nem todos os serviços ou aplicações disponíveis na web são acessíveis para todos. Estima-se que cerca de um quinto da população da União Europeia tem algum tipo de incapacidade, quer física, cognitiva, visual ou auditiva. Com esta percentagem significativa, é importante que a web forneça alternativas acessíveis, de modo a incluir o máximo de cidadãos, promovendo a independência dos mesmos e contribuindo para uma maior equidade social. A W3C desenvolveu um conjunto de recomendações para desenvolvedores web que desejam tornar o seu conteúdo acessível, sendo já consideradas como o padrão a seguir em legislações internacionais. Porém, por serem difíceis de interpretar, foi criado o projeto WAI-Tools, no qual um dos objetivos principais é o desenvolvimento de regras claras e reproduzíveis, focadas nas recomendações mencionadas. Com estas regras, é despoletada a harmonização dos resultados, ferramentas e métodos de avaliação de acessibilidade. Um outro objetivo do projeto foi a criação de um formato único de resultados de testes de acessibilidade, permitindo que várias ferramentas possam estruturar da mesma maneira os seus resultados. Um último objetivo, e foco deste trabalho, era o desenvolvimento de uma plataforma de monitorização de conformidade de acessibilidade em grande-escala onde, com a conciliação das regras desenvolvidas e o formato normalizado dos resultados daí originados, fosse possível agrupar informação de várias ferramentas e entidades e incentivar a uma constante melhoria e apreço pela acessibilidade digital. Para alcançar este objetivo, foi realizado um levantamento de requisitos de plataformas de monitorização existentes, dentro e fora do âmbito de acessibilidade, identificando as suas necessidades e funcionalidades comuns. Tendo em conta este estudo, e pareceres de alguns parceiros do projeto europeu, foi desenhado um modelo de dados e estruturados os tipos de navegação, e correspondentes vistas gráficas, apropriados aos dados a monitonizar. Depois do processo de implementação da plataforma, foram realizados testes com utilizadores para verificar se a plataforma apresentava problemas de usabilidade, e, por fim, realizadas alterações tendo em conta os resultados dos testes.
With the increasing modernization of processes in society, the Internet has already become a tool used by millions of people every day. Despite this magnitude, not all services or applications available on the web are accessible to everyone. It is estimated that about a fifth of the population in the European Union has some kind of disability, whether physical, cognitive, visual or hearing. With this significant percentage, it is important that the web provides accessible alternatives, in order to include as many citizens as possible, promoting their independence and contributing to greater social equity. The W3C has developed a set of recommendations for web developers who want to make their content accessible and are already considered to be the standard to follow in international legislation. However, as they are difficult to interpret, theWAI-Tools project was created, in which one of the main objectives is the development of clear and reproducible rules, focused on the mentioned recommendations. With these rules, the harmonization process of results, tools and methods for assessing accessibility is triggered. Another objective of the project was to create a standardized format for accessibility test results, allowing several tools to structure their results in the same way. A final objective, and focus of this dissertation, was the development of a large-scale accessibility compliance monitoring platform where, with the conciliation of the developed rules and the standardized format of the results resulting from it, it should be possible to group information from various tools and entities and encourage constant improvement and appreciation for digital accessibility. To achieve this goal, a survey of requirements for existing monitoring platforms was carried out, both within and outside the scope of accessibility, identifying their common needs and features. Taking this survey into account, and the opinions of some partners of the European project, a data model was designed and the types of navigation appropriate to the data to be monitored, and corresponding graphical views, were structured. After the platform implementation process, tests were carried out with users to check if the platform had usability problems, and, finally, changes were made considering the results of these tests.
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Ireland, Sean S. „Characterization and implementation of a UV/O₃ pilot-scale prototype for disinfecting and recycling poultry chiller wastewater“. 2004. http://purl.galileo.usg.edu/uga%5Fetd/ireland%5Fsean%5Fs%5F200412%5Fms.
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Duncan, William F. A. (William Frederick Alexander), und Al Mattes. „Field scale prototype anaerobic/wetlands cells for removing heavy metals from water leaching from a historical capped landfill“. 1999. http://hdl.handle.net/2429/9632.
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A passive treatment system utilizing an anaerobic digester followed by three plant based treatment cells has been built in Trail, British Columbia, site of the world's largest nonferrous smelter. Water becomes contaminated with heavy metals as it passes through discarded materials from the smelter and through a former Arsenic storage area. This water, containing large amounts of dissolved Zn., Cd., and As is collected and pumped to the pilot scale treatment facility.
The facility, capable of treating 12-15,000 L of water daily includes a large anaerobic
digester that utilizes waste by-product from the pulp and paper industry as a matrix for
Sulphur Reducing Bacteria. The partially treated water then flows through a series of
hydroponics cells containing a mixture of metal-resistant fast growing plants. The system uses gravity based hydroponics flow-through and solar powered aeration cells between garden cells.
During the summer months transpiration will yield expected (or greater) results. All plants are perennials and after two months of operation there were no signs of impaired plant functioning.
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Sea, Li-Ming, und 施力銘. „The Embedded Platform Prototype Design And Development For Small Scale Electric Toy Product Based On Raspberry Pi System“. Thesis, 2019. http://ndltd.ncl.edu.tw/handle/hu87n3.
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碩士國立臺灣科技大學
電子工程系
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The Raspberry Pi is developed by the British Raspberry Pi Foundation and is a series of small computer systems suitable for embedded platform development. The hardware central operating SoC components of this series of systems are based on the current mainstream ARM architecture. The software part is based on Linux as the operating platform. In the environment in which the author works, there are more and more SoC solutions like this that are used by engineers. This thesis is based on this popular embedded system, trying to develop a variety of small electronic toy prototypes, including: bicycle wheel rotation display device, infant-specific kaleidoscope projection music box and pet-specific ball-throwing toy electric car, and attempted in the development of these toy prototypes, the relevant core knowledge systems are summarized. The goal of this paper is to try to sort out the highly reusable embedded firmware framework and the highly reusable software components in the prototype development of this type of product based on the core knowledge summarized in the development process.
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Beeny, Bradley Aaron 1988. „Thermal Hydraulic Analysis of a Reduced Scale High Temperature Gas-Cooled Reactor Test Facility and its Prototype with MELCOR“. Thesis, 2012. http://hdl.handle.net/1969.1/148182.
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Pursuant to the energy policy act of 2005, the High Temperature Gas-Cooled Reactor (HTGR) has been selected as the Very High Temperature Reactor (VHTR) that will become the Next Generation Nuclear Plant (NGNP). Although plans to build a demonstration plant at Idaho National Laboratories (INL) are currently on hold, a cooperative agreement on HTGR research between the U.S. Nuclear Regulatory Commission (NRC) and several academic investigators remains in place.
One component of this agreement relates to validation of systems-level computer code modeling capabilities in anticipation of the eventual need to perform HTGR licensing analyses. Because the NRC has used MELCOR for LWR licensing in the past and because MELCOR was recently updated to include gas-cooled reactor physics models, MELCOR is among the system codes of interest in the cooperative agreement. The impetus for this thesis was a code-to-experiment validation study wherein MELCOR computer code predictions were to be benchmarked against experimental data from a reduced-scale HTGR testing apparatus called the High Temperature Test Facility (HTTF). For various reasons, HTTF data is not yet available from facility designers at Oregon State University, and hence the scope of this thesis was narrowed to include only computational studies of the HTTF and its prototype, General Atomics’ Modular High Temperature Gas-Cooled Reactor (MHTGR). Using the most complete literature references available for MHTGR design and using preliminary design information on the HTTF, MELCOR input decks for both systems were developed. Normal and off-normal system operating conditions were modeled via implementation of appropriate boundary and inititial conditions. MELCOR Predictions of system response for steady-state, pressurized conduction cool-down (PCC), and depressurized conduction cool-down (DCC) conditions were checked against nominal design parameters, physical intuition, and some computational results available from previous RELAP5-3D analyses at INL.
All MELCOR input decks were successfully built and all scenarios were successfully modeled under certain assumptions. Given that the HTTF input deck is preliminary and was based on dated references, the results were altogether imperfect but encouraging since no indications of as yet unknown deficiencies in MELCOR modeling capability were observed. Researchers at TAMU are in a good position to revise the MELCOR models upon receipt of new information and to move forward with MELCOR-to-HTTF benchmarking when and if test data becomes available.
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Klein-Miloslavich, Andreas. „Modeling, simulation, hardware development, and testing of a lab-scale airborne wind energy system“. Thesis, 2020. http://hdl.handle.net/1828/11508.
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Airborne Wind Energy Systems (AWES) harness the power of high-altitude winds using tethered planes or kites. Continuous and reliable operation requires that AWES become autonomous devices, but the wind intermittency forces the system to repeatedly take-off to start, and land to shut-off. Therefore, a common approach to facilitate the operation is implementing Vertical take-off and landing (VTOL) functionality. This thesis models and simulates AWES flights working towards the implementation of flight controller hardware and autonomous operation of an AWES demonstrator platform.
The Ardupilot open-source autopilot platform provides a convenient tool for modeling, simulation, and hardware implementation of small-scale airplanes. An AWES lab-scale demonstrator was developed to obtain operational insight, get preliminary flight data, and real-world experience in this technology. A quadplane was developed by combining a structurally reinforced glider with VTOL and autopilot components. Its performance is obtained from static and aerodynamic studies and converted into the Ardupilot parameter format to define it in the simulation.
An AWES flight model was developed from the ground up to evaluate the performance of a simple flight controller in trajectory tracking. The Ardupilot Software-in-Loop (SIL) tool expands the simulation capabilities by running the flight controller code without requiring any hardware. This allowed controller tuning and flight plan evaluation with a more advanced fight model. AWES crosswind flight simulation was only possible due to the incorporation of an elastic tether and an ideal winch into the physics model. As a result, different trajectories and configurations were tested to find the optimal parameters that were uploaded to the flight controller board.
The operational capabilities of the AWES demonstrator were expanded with a flight testing campaign. By targeting individual objectives, each test gradually increased its complexity and ensured that the flight envelope was safely expanded. The results were validated with the simulation before moving on to the next flight test. The testing campaign is still underway due to challenges and limitations presented by the legal and logistical aspects of operating the quadplane. However, preliminary flight tests in VTOL mode have been completed and were consistent with the simulated results in terms of autonomous waypoint navigation and attitude control.Graduate
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Silva, Manuela Corrêa Alves. „Stress-strain response of soft soils stabilised with alkali activated industrial by-products“. Doctoral thesis, 2021. http://hdl.handle.net/1822/75516.
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Tese de doutoramento em Engenharia CivilAlternative binders based on the alkaline activation technology have been strongly investigated over the last decades as a potential replacement for Portland Cement. However, little research has been devoted to the shear behaviour of soft soils stabilised with those type of binders and their numerical modelling using constitutive models. This PhD thesis aims to deepen the knowledge in this area through the characterisation of the short- and long-term shear behaviour of soft soils stabilised with alkali-activated binders and the numerical modelling of the stress-strain behaviour of these geomaterials using a advanced constitutive model. In this context, triaxial tests were undertaken, after 28 and 90 curing days, in both a sandy lean clay and clay with high water content at reconstituted and stabilised states using alkali-activated blast furnace slags. The impact of the stress-history, represented by the overconsolidation ratio, and stress-state, represented by the initial mean effective stress, were investigated. Oedometer and isotropic consolidation tests were also undertaken. Scanning electron microscopy with energy dispersive spectroscopy, x-ray powder diffraction and leachate analyses were carried out to investigate the nature of the binding phases formed and the risk of contamination of soils. The results were used to calibrate an advanced kinematic hardening constitutive model proposed by Rouainia and Muir Wood, 2000 for natural clays. It was the first attempt of using this constitutive model in artificially cemented soils. Additionally, the opportunity to be integrated within a research project related to the application of alkali-activated industrial wastes in situ allowed me to be deeply involved in constructing a full-scale prototype of a (sub)base layer stabilised with alkali-activated binders and conventional binders. Big challenges arose, including the definition of a construction methodology, equipment selection, on-site handling of distinct materials, quality control techniques, among others. The in situ performance of the stabilised geomaterials was assessed through falling weight deflectometer tests, plate load field tests and unconfined compressive strength tests after 36 and 90 days. For each layer, it was estimated the financial cost of the construction and the equivalent CO2 emissions. The work showed the feasibility of the on-site application of alkali-activated binders in the stabilisation of soil layers in the context of transport infrastructures.
Os ligantes alcalinos têm sido fortemente investigados nas últimas décadas como um potencial substituto do cimento Portland. Contudo, o comportamento ao corte de solos estabilizados com este tipo de ligantes é ainda uma área pouco explorada atualmente, juntamente com o uso de modelos constitutivos. A presente tese de doutoramento visa aprofundar o conhecimento existente nesta área, através da caracterização do comportamento ao corte de solos moles estabilizados com ligantes alcalinos a curto e longo prazo e a modelação numérica do comportamento tensão-extensão desses geomateriais utilizando um modelo constitutivo avançado. Nesse contexto, foram realizados ensaios triaxiais, ensaios edométricos e de consolidação isotrópica, numa argila magra arenosa e numa argila com alto teor em água, ambos no estado reconstituído e estabilizado com escórias de alto-forno ativadas por álcalis, aos 28 e 90 dias de cura. O impacto do grau de sobreconsolidação, representado pela razão de sobreconsolidação, e do estado de tensão in situ, representado pela tensão média efetiva inicial, foram investigados no comportamento ao corte desses geomateriais. Foram realizadas análises de microscopia eletrônica de varrimento com espectroscopia de energia dispersiva e difração de raios-X e testes de lixiviados para investigar a natureza dos géis formados e o risco de contaminação dos solos. Os resultados foram utilizados na calibração de um modelo constitutivo de endurecimento cinemático proposto por Rouainia and Muir Wood, 2000 para argilas naturais que, até ao momento, não tinha sido utilizado em solos artificialmente cimentados. Adicionalmente, a oportunidade de estar integrada num projeto de investigação relacionado com a construção à escala real de uma camada de (sub)base estabilizada com ligantes alcalinos e ligantes convencionais possibilitou-me enveredar por esta temática. Grandes desafios foram encontrados do longo deste projeto, entre os quais, a definição de uma metodologia de construção, a seleção de equipamentos, manuseio dos materiais in situ, definição dos ensaios de controle de qualidade, etc. O desempenho in situ dos geomateriais estabilizados foi avaliado através de ensaios de capacidade de carga com defletómetro de impacto, ensaios de carga em placa e de compressão uniaxial aos 36 e 90 dias. Para cada camada foram também estimados os custos financeiros de construção e as emissões de CO2 equivalentes. Este projeto mostrou a viabilidade de utilização local dos ligantes alcalinos para a estabilização de camadas de solo no contexto das infraestruturas de transporte.
Fundação para a Ciência e a Tecnologia (FCT)
This research work was co-financed by the European Social Fund (FSE) through the Northern Regional Operational Program
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PALOMBA, VALERIA. „Thermal energy storage systems for low-grade heat applications: Design and experimental testing of lab-scale prototypes“. Doctoral thesis, 2017. http://hdl.handle.net/11570/3116364.
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The main objective of this thesis is the development of prototypes of thermal energy storages
suitable for coupling with low-grade waste heat (e.g. non-concentrating solar, industrial
process heat) and their experimental testing.
Benefits of thermal energy storages are several, but the experience in non-sensible heat
storage is still limited, especially in the design of prototypes. High temperature heat storage
(T >150°C) has been the subject of a quite extensive research, but low-grade heat sources are
still not fully exploited, due to the competition with water, that is available at a risible cost.
In the present thesis, two different technologies were investigated, latent heat and adsorption
heat, by design and experimental testing of lab-scale storages. In particular, data from
experimental testing on Phase Change Materials carried out at CNR-ITAE were used for the
development of thermal energy storages using latent heat technology (with phase change
materials). Since only limited data on PCM-based devices in the investigated temperature
range were available, two approaches were followed: a custom fin-and-tube heat exchanger
and a commercial plate heat exchanger were tested with the same PCM (a paraffin) and the
results used for a design analysis. In order to complete the analysis, a simplified numerical
model was developed through the commercial software COMSOL Multiphysics and validated
against experimental results. The model was able to describe the behaviour of the
fin-and-tube system with low computational effort, showing good possibility for a future
design optimization and easy adaptability to different configurations.
Measurement on adsorption equilibrium curves available for adsorbent materials, instead,
were used as the input for the development of a thermal energy storage making use of
adsorption technology. While the storage was designed to use the same heat sources as the
latent thermal ones, different operating conditions on the user-side were considered, taking
into account both cold or hot storage possibilities.
The experimental measurements on both the technologies highlighted the good potential
of the investigated systems and therefore that further research in the specific temperature range
analysed is feasible and will allow overcoming the limitations that still exist. However, the
intense research activity that is on-going in the field of thermal energy storage cannot preclude
from a standardization, both in the definition of relevant indicators and the assessment of the systems. To this aim, an attempt has been made at comparing the developed storages (2
latent heat storages and 1 adsorption storage), by defining common performance indicators
and evaluating whether they can be applied to such different cases, in terms of characteristics,
sizes and application.
Results obtained have shown that both technologies allow reaching a higher energy
storage density than water, under all the examined conditions (i.e. charging temperature of
75°C to 90°C), with values up to 900 kJ/kg in the case of the adsorption heat storage. The
operating parameters affecting storage operation were analysed as well: indeed, it was found
that the performance of the storages is strongly dependent not only on the heat sources and
external ambient conditions, but also on the control of the system (i.e. the flow rate imposed,
the part load operation) and the construction features, such as the material used for the shells
or the insulation.
Finally, the methodology suggested for the evaluation of the storage could be successfully
applied to all the systems, allowing a qualitative and quantitative comparison.
The main outcomes of the work here reported can then lead the path towards the optimization
of the heat storage systems, from lab-scale to pre-commercial ones, thus increasing
the technology readiness level and making a step forward towards practical application.