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Developing a QFD-based design-integrated structural analysis methodologyMobasseri, Seyed Omid January 2012 (has links)
Design of the mechanical components greatly depends on their expected structural performances. In modern design applications these performances are quantified by computer-based analysis and occasionally confirmed by experimental measurements or theoretical calculations. The dependency of the mechanical product to the structural analysis process is more significant under the product’s multi-functionality aspect that requires analyses for a variety of Variable Input Parameters, to obtain various structural responses and against more than one failure or design criterion. Structural analysis is known as the expert field, which requires an upfront investment and facilitation to be implemented in commercial design environment. On the other hand, the product design process is a systematic and sequential activity that put the designer in the central role of decision making. Lack of mutual understanding between these two disciplines reduces the efficiency of the structural analysis for design. This research aims to develop an integrated methodology to embed the structural analysis in the design process. The proposed methodology in this research combines the benefits of state-of-the-art approaches, early simulation and Validation and Verification practice, towards the specified aim. Moreover the novelty of the proposed methodology is in creative implication of Quality Function Deployment method to include the product’s multi-functionality aspect. The QFD-Based Design Integrated Structural Analysis methodology produces a reliable platform to increase the efficiency of the structural analysis process for product design purpose. The application of this methodology is examined through an industrial case-study for the telescopic cantilever boom, as it appears in Access platforms, and Cranes products. Findings of the case-study create a reliable account for the structural performance in early stages of the design, and ensure the functionality of the proposed methodology.
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Heat Generation Measurements of Prismatic Lithium Ion BatteriesChen, Kaiwei January 2013 (has links)
Electric and hybrid electric vehicles are gaining momentum as a sustainable alternative to conventional combustion based transportation. The operating temperature of the vehicle will vary significantly over the vehicle lifetime and this variance in operating temperature will strongly impact the performance, driving range, and durability of batteries used in the vehicles.
In the first part of this thesis, an experimental facility is developed to accurately quantify the effects of battery operating temperature on discharge characteristics through precise control of the battery operating temperatures, utilizing a water-ethylene glycol solution in a constant temperature thermal bath. A prismatic 20Ah LiFEPO4 battery from A123 is tested using the developed method, and temperature measurements on the battery throughout discharge show a maximum variation of 0.3°C temporally and 0.4°C spatially at a 3C discharge rate, in contrast to 13.1°C temperature change temporally and 4.3°C spatially when using the conventional air convection temperature control method under the same test conditions. A comparison of battery discharge curves using the two methods show that the reduction in spatial and temporal temperature change in the battery has a large effect on the battery discharge characteristics. The developed method of battery temperature control yields more accurate battery discharge characterization due to both the elimination of state-of-charge drift caused by spatial variations in battery temperature, and inaccurate discharge characteristics due to battery heat up at various discharge and ambient conditions. Battery discharge characterization performed using the developed method of temperature control exhibits a reduction in battery capacity of 95% when the operating temperature is decreased from 20°C to -10°C at 3C discharge rate. A reduction of 35% in battery capacity is observed when for the same temperature decrease at a 0.2C discharge rate. The observed effect of operating temperature on the capacity of the tested battery highlights the importance of an effective thermal management system, the design of which requires accurate knowledge of the heat generation characteristics of the battery under various discharge rates and operating temperatures.
In the second part of this thesis, a calorimeter capable of measuring the heat generation rates of a prismatic battery is developed and verified by using a controllable electric heater. The heat generation rate of a prismatic A123 LiFePO4 battery is measured for discharge rates ranging from 0.25C to 3C and operating temperature ranging from -10°C to 40°C. Results show that the heat generation rates of Lithium ion batteries are greatly affected by both battery operating temperature and discharge rate. At low rates of discharge the heat generation is not significant, even becoming endothermic at the battery operating temperatures of 30°C and 40°C. Heat of mixing is observed to be a non-negligible component of total heat generation at discharge rates as low as 0.25C for all tested battery operating temperatures. A double plateau in battery discharge curve is observed for operating temperatures of 30°C and 40°C. The developed experimental facility can be used for the measurement of heat generation for any prismatic battery, regardless of chemistries. The characterization of heat generated by the battery under various discharge rates and operating temperatures can be used to verify the accuracy of battery heat generation models currently used, and for the design of an effective thermal management system for electric and hybrid electric vehicles in the automotive industry.
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Heat Generation Measurements of Prismatic Lithium Ion BatteriesChen, Kaiwei January 2013 (has links)
Electric and hybrid electric vehicles are gaining momentum as a sustainable alternative to conventional combustion based transportation. The operating temperature of the vehicle will vary significantly over the vehicle lifetime and this variance in operating temperature will strongly impact the performance, driving range, and durability of batteries used in the vehicles.
In the first part of this thesis, an experimental facility is developed to accurately quantify the effects of battery operating temperature on discharge characteristics through precise control of the battery operating temperatures, utilizing a water-ethylene glycol solution in a constant temperature thermal bath. A prismatic 20Ah LiFEPO4 battery from A123 is tested using the developed method, and temperature measurements on the battery throughout discharge show a maximum variation of 0.3°C temporally and 0.4°C spatially at a 3C discharge rate, in contrast to 13.1°C temperature change temporally and 4.3°C spatially when using the conventional air convection temperature control method under the same test conditions. A comparison of battery discharge curves using the two methods show that the reduction in spatial and temporal temperature change in the battery has a large effect on the battery discharge characteristics. The developed method of battery temperature control yields more accurate battery discharge characterization due to both the elimination of state-of-charge drift caused by spatial variations in battery temperature, and inaccurate discharge characteristics due to battery heat up at various discharge and ambient conditions. Battery discharge characterization performed using the developed method of temperature control exhibits a reduction in battery capacity of 95% when the operating temperature is decreased from 20°C to -10°C at 3C discharge rate. A reduction of 35% in battery capacity is observed when for the same temperature decrease at a 0.2C discharge rate. The observed effect of operating temperature on the capacity of the tested battery highlights the importance of an effective thermal management system, the design of which requires accurate knowledge of the heat generation characteristics of the battery under various discharge rates and operating temperatures.
In the second part of this thesis, a calorimeter capable of measuring the heat generation rates of a prismatic battery is developed and verified by using a controllable electric heater. The heat generation rate of a prismatic A123 LiFePO4 battery is measured for discharge rates ranging from 0.25C to 3C and operating temperature ranging from -10°C to 40°C. Results show that the heat generation rates of Lithium ion batteries are greatly affected by both battery operating temperature and discharge rate. At low rates of discharge the heat generation is not significant, even becoming endothermic at the battery operating temperatures of 30°C and 40°C. Heat of mixing is observed to be a non-negligible component of total heat generation at discharge rates as low as 0.25C for all tested battery operating temperatures. A double plateau in battery discharge curve is observed for operating temperatures of 30°C and 40°C. The developed experimental facility can be used for the measurement of heat generation for any prismatic battery, regardless of chemistries. The characterization of heat generated by the battery under various discharge rates and operating temperatures can be used to verify the accuracy of battery heat generation models currently used, and for the design of an effective thermal management system for electric and hybrid electric vehicles in the automotive industry.
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Model moderní komerční prádelny / Model of an up-to-date commercial laundry premiseTůma, Zdeněk January 2009 (has links)
The thesis deals with a design of an up-to-date commercial laundry with focus on equipments applied. The proces is studied and analysed throughly first. Important aspects for choice of equipments are mentioned (i.e. steam, power and natural gas consumptions. These informations are summarized from data sheets provided by manufacturers as well as from experimental measurements in existing facilities.
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RAILROAD TRACK PRESSURE MEASUREMENTS AT THE RAIL/TIE INTERFACE USING TEKSCAN SENSORSStith, Jason C. 01 January 2005 (has links)
It has been desirable for years to develop non-intrusive/non-invasiveprocedures to determine the pressures and stresses at various levels andinterfaces in the railroad track structure in order to optimize track designs andimprove subsequent track performance. Recent research has developedsatisfactory procedures for measuring pressures in the track structure at theballast/subballast/subgrade levels using earth pressure cells. The researchreported in this thesis documents the development of a technique for measuringthe pressures in the track, at the rail/tie plate/tie interfaces, using a very thinpressure sensitive Tekscan sensor. The Tekscan Measurement System uses asensor composed of a matrix-based array of force sensitive cells, similar to ministrain gauges, to obtain accurate pressure distributions between two surfaces inthe track. This thesis specifically describes: 1) the optimum procedure to installthe sensors into the track, 2) the recommended practices to effectively collectdata with the software, and 3) the accepted techniques for analyzing the results.Both laboratory calibration and in-track testing have been conducted and theresults are presented. The findings attest to the usefulness and practicality of theprocedure for accurately measuring pressures in railroad tracks. The proceduremay also be applicable for a wide variety of specific track related measurementssuch as validating curve geometric criteria, assessing crossing diamond impactpressures, and evaluating the advantages/disadvantages of various types of tieplates, fastenings and tie compositions.
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Vliv vlhkosti materiálu na tepelné vlastnosti rukavic / The influence of moisture on the thermal properties of the glovesJaníčková, Žaneta January 2019 (has links)
This diploma thesis is focused on the assessment of the influence of moisture on the thermal properties of the gloves. The first part of the thesis deals with the research of topics related to the given issue as well as with the derivation of the computational relations needed for evaluation of experimental measurements. The main focus of the work lies on defining the hypotheses and experiments that are used to verify the influence of moisture on the thermal resistance of gloves. As for the experimental part, it describes the individual methods of moistening the gloves from which the moistening through the air humidity and the moistening by the immersion were analysed. To verify the suitability of selected moistening methods, the tested glove samples were measured on the thermal manikin both in a dry and a moistened state under the conditions defined by ČSN EN 511 and ČSN EN ISO 15831 standards. Individual states were repeatedly measured and afterwards the progresses of thermal resistance depending on time were graphically displayed. The thesis also includes analysis of measurement uncertainties as well as evaluation of measurement repeatability. From the obtained results, both the defined hypotheses and theoretical assumptions about the decrease of the thermal resistance of a textile material due to the influence of moisture were confirmed in the conclusion of the diploma thesis.
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Rozbor vlastností materiálu kompozitních desek na bázi cementu a organických vláken v návaznosti na jeho využití v rámci návrhu interiérových schodišť / Analysis of material properties of composite boards based on cement and organic fibers in relation to its use in the design of interior staircasesNespěšný, Ondřej January 2020 (has links)
Cement-based composite boards reinforced by organic fiber, commonly known as cement fiber boards are universal and environmental material. Nowadays they are commonly used in construction industry in the form of facade facing for ventilated facades, interior and exterior ceilings or as a lost formwork for the bridge constructions. In these ways of using the cement fiber boards are strained mainly perpendicularly to their median plane. Material characteristics for this kind of strain are declared by the manufacturers. This diploma thesis is focused on ways of using the cement fiber boards reinforced by organic fiber as prefabricated, constructional material for interior staircases. In this case, every segment is strained even in its median plane. This way of strain is atypical and is not declared by the manufacturers in the manufacturer's technical sheets. The main goal of the diploma thesis was to experimentally determine the material characteristics in relation to the possibility of using the cement fiber boards reinforced by organic fiber for the construction of interior stairways. Material characteristics were determined by using Czech technical standards and information from professional literature. Testing tools made by 3D printing were used in the measurements. The possibilities of connecting cement fiber boards by mechanical and glued joint were checked out. The trial “stand” from CLT boards was designed for the real testing of single-arm and double-arm staircases. The outcomes of the experimental measurements confirmed the possibility to use the cement fiber boards for interior stairways. It is necessary to support the design of the staircase by static calculations and to respect the design of the dimensions of the individual segments in the implementation.
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Systém pro hodnocení energetické náročnosti procesu profesní údržby prádla / System for energy intensity evaluation in professional laundry processBobák, Petr January 2009 (has links)
This thesis tries to solve a problem of energy intensity evaluation in professional laundry process via analysis of factors, which influence the energy intensity of the process and presents some computational tools needed for this challenge.
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Etude des propriétés thermodynamiques des nouveaux fluides frigorigènes / Thermodynamics properties of new refrigerantsEl abbadi, Jamal 02 December 2016 (has links)
La connaissance des propriétés thermodynamiques et des diagrammes de phases des composés fluorés est indispensable pour le dimensionnement et l'optimisation des systèmes thermodynamiques. Les applications sont nombreuses : réfrigération, récupération de chaleur (ORC), pompe à chaleur, climatisation automobile. Du fait des contraintes environnementales (la F-gaz pour l'UE) liées au fait que les fluides actuellement utilisés doivent être inoffensifs vis-à-vis de la couche d'ozone mais aussi posséder un pouvoir de réchauffement climatique bas (GWP CO2=1, valeur de référence), les chimistes doivent développer de nouvelles molécules qui répondent à ce nouveau cahier des charges. Actuellement, ils ont mis au point des fluides de la famille des HFO dont le plus célèbre est le HFO1234yf. Son GWP est faible (4) tout comme celui de ses principaux isomères, le HFO1234ze et le HFO1234zd. Si le fluide pur ne convient, des mélanges (blends) doivent être élaborés. Si le fluide pur ne convient pas pour les applications souhaitées, des mélanges doivent être élaborés.L'objectif de cette thèse est d'étudier plusieurs HFOs en corps purs et en mélanges et de développer/comparer des modèles thermodynamiques permettant de prédire les diagrammes de phases et les densités de ces fluides. Ces modèles doivent pouvoir être transposables vers l'industrie. Le CTP dispose de plusieurs équipements permettant d'acquérir des données expérimentales. Le densimètre à tube vibrant sera utilisé pour acquérir des données de masse volumique, et une cellule d'équilibre entre phase (technique statique-analytique) pour acquérir des données d'équilibre liquide vapeur. Les équations d'état cubiques seront utilisées pour le traitement des données. Une nouvelle équation d'état plus précise pour la prédiction des masses volumiques sera présentée. Une comparaison en termes de description des diagrammes de phases et des propriétés volumétriques sera également effectuée. / The knowledge of the thermodynamic properties and phase diagrams of fluorinated compounds is essential for the design and optimization of thermodynamic systems. There are many applications: refrigeration, organic Rankine cycle (ORC), heat pump, and air conditioning systems. Due to the environmental constraints (F-gaz for the EU) related to the fact that the fluids being used must be harmless to the ozone layer, but also with a low global warming potential (GWP CO2 = 1 reference value), the chemists must develop new molecules responding to these constraints. Today, they have developed fluids called HFOs whose most famous is the HFO1234yf, with a low GWP (4), along with his isomers HFO1234ze and HFO1234zd. If the pure fluid is not suitable for the applications, blends should be developed instead. The objective of these theses is to study several HFOs, in pure compounds and mixtures and develop / compare thermodynamic models in order to predict the phase diagram and density of these fluids. These models should be transferable to industry. The CTP has several equipments to acquire experimental data. The vibrating-tube densimeter will be used to acquire density data, and equilibrium cell (static-analytic method) to acquire liquid-vapor equilibrium data. The cubic equations of state will be used for data treatment. A new equation of state more accurate for density prediction will be presented. A comparison in terms of phase diagrams and density prediction will be carried out.
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Estudo dos limites de inflamabilidade em mistura etanol-ar-diluente / Study of flammability limits in ethanol-air-diluent mixtureEscalante, Edwin Rios [UNESP] 12 July 2016 (has links)
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Previous issue date: 2016-07-12 / Agência Nacional de Petróleo, Gás Natural e Biocombustíveis (ANP) / Os limites superior e inferior de inflamabilidade são as concentrações máximas e mínimas de um combustível no ar, respectivamente, na qual uma chama pode se propagar, eles são considerados ferramentas chaves na predição do fogo, avaliando a possibilidade de explosão e projeto de sistemas de proteção. Existe interesse em encontrar os limites de inflamabilidade do etanol misturado com um diluente para pressões reduzidas para o futuro uso desse biocombustível em aplicações aeronáuticas tendo em conta a altitude típica de um avião comercial (<40 000 ft.). Neste trabalho foi desenvolvido experimentalmente a inflamabilidade do combustível líquido: Etanol hidratado e utilizou-se como gás diluente o nitrogênio. A bancada experimental usada, consiste de um recipiente esférico de 20 litros como câmara de aquecimento, uma fonte de ignição por faísca localizada na parte central da câmara. O líquido foi injetado com uma seringa de precisão de 1ml de volume para logo se evaporar no interior da câmara, o nitrogênio e ar foram injetados usando pressões parciais. O método para medir a inflamabilidade foi baseado na ignição elétrica e observação visual da propagação da chama conforme norma ASTM E-681. Primeiro os limites superior e inferior de inflamabilidade foram determinados para elevada temperatura (60℃) e pressão ambiente (101,325 kPa) para comparar os resultados com os dados publicados na literatura científica. Depois procedeu-se trabalhar com pressões reduzidas (80, 60, 40 e 20 kPa) para essa mesma temperatura, finalmente foram realizados testes para uma temperatura maior (110℃) para avaliar a influência da temperatura sobre os limites de inflamabilidade de misturas etanol-ar-diluente, os resultados foram plotados como função da relação e adição de nitrogênio e esses gráficos seguem a mesma tendência de trabalhos publicados na literatura científica. / The upper and lower limits of flammability are the maximum and minimum concentrations of a fuel in the air, respectively, in which the flame can spread; they are considered key tools for predicting fire, evaluating the possibility of explosion and protection system design. There is interest in finding the flammability limits of ethanol mixed with a diluent to reduced pressure for future use this biofuel in aeronautical applications having regard the typical height of a commercial aircraft (<40, 000 ft.). In this experimental work was carried flammability of the liquid fuel: Ethanol hydrate and used as a diluent gas nitrogen. The experimental apparatus consists of a 20 liters spherical vessel as heating chamber, a spark ignition source located in the central part of the chamber. The liquid was injected with a 1 ml syringe precision volume immediately evaporates in the chamber; nitrogen and air were injected using partial pressures. The method for flammability measuring was based in both visual observation electric ignition and flame propagation as defined by ASTM E-681. First, the upper and lower flammability limits were determined to a high temperature (60 ℃) and ambient pressure (101.325 kPa) to compare the results with data published in the scientific literature. After, we proceeded to work at reduced pressures (80, 60, 40 and 20 kPa) to same temperature. Finally, tests were carried out for a higher temperature (110 ℃) to evaluate the influence of temperature on the flammability limits ethanol-air-diluent mixtures, the results were plotted as a function of the relationship and adding nitrogen and these graphs follow the same trend of papers published in scientific literature.
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