Dissertations / Theses on the topic 'Mixed Compression'
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Nori, Venkata Narasimham. "Unsteady flow in a mixed-compression inlet at Mach 3.5." [Gainesville, Fla.] : University of Florida, 2003. http://purl.fcla.edu/fcla/etd/UFE0000760.
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Enriquez, Jesus A. "Lossless compression of Bayer array images using mixed-lattice lifting transforms." To access this resource online via ProQuest Dissertations and Theses @ UTEP, 2008. http://0-proquest.umi.com.lib.utep.edu/login?COPT=REJTPTU0YmImSU5UPTAmVkVSPTI=&clientId=2515.
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Webb, Nathan Joseph. "Control of Supersonic Mixed-Compression Inlets Using Localized Arc Filament Plasma Actuators." The Ohio State University, 2010. http://rave.ohiolink.edu/etdc/view?acc_num=osu1274714729.
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Warren, Arthur H. "Propulsion system analysis for conceptual design : drag and losses of nozzles and mixed compression inlets /." Thesis, This resource online, 1993. http://scholar.lib.vt.edu/theses/available/etd-07112009-040259/.
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Duncan, Sean. "Implementation of Slater Boundary Condition into OVERFLOW." University of Cincinnati / OhioLINK, 2013. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1368026265.
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Sengor, Mahmut Yavuz. "The Deformation Characteristics Of Deep Mixed Columns In Soft Clayey Soils: A Model Study." Phd thesis, METU, 2011. http://etd.lib.metu.edu.tr/upload/12613075/index.pdf.
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Deep Mixing involves the introduction of cementitious or specially formulated solutions directly into the ground through the use of purpose built blending injection augers. The system is mainly designed to increase strength and reduce compressibility of treated soil.
In the first stage of the research effective mixture ratios and mixture types of stabilizing agents were investigated for soft clays (CL form Eymir lake and kaolinite) by means of unconfined compression (UC) tests on stabilized soils. The unconfined compressive strength (UCS) values were obtained for 7,28,90 and 365 days of curing time. The ratio of elastic modulus at 50% failure load (E50) to (UCS) of the stabilizing agents were also investigated.
In the second part of the research programme, deep mixed model columns with the three column materials and four different column spacings are formed within the large scale consolidation tanks, and the consolidation characteristics of deep mixed improved clay were investigated.
Based on the results of large scale consolidation tests on deep mixed columnar improved soft clay, compressibility characteristics of improved soft clay were determined in relation to spacing of columns namely, effective replacement ratio and binder content. The cement content (also UCS) of the column material was found to be the most important parameter for the improvement effects of DMM applications. Validity of the relations for the estimation of bulk compression modulus of soilcrete were discussed. The use of constrained modulus of the soil and the column material were found to be effective in predicting the compression modulus of the soilcrete. Settlement reduction factor versus replacement ratio and cement content relations were determined which may be used for preliminary design works. The stresses on the soil and the columns were backcalculated from the settlement values. The stress ratios were obtained.
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Redford, Tim. "Effects of incomplete fuel-air mixing on the performance characteristics of mixed compression, shock-induced combustion ramjet, shcramjet, engines." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1998. http://www.collectionscanada.ca/obj/s4/f2/dsk2/tape17/PQDD_0010/MQ34109.pdf.
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Friedlander, David J. "Understanding the Flow Physics of Shock Boundary-Layer Interactions Using CFD and Numerical Analyses." University of Cincinnati / OhioLINK, 2013. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1367928417.
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Bagley, Angus H. "Proteomic and bioinformatic investigation of chronic wounds using non-invasive sampling to assess wound status and pathology." Thesis, Queensland University of Technology, 2022. https://eprints.qut.edu.au/235131/1/Angus_Bagley_Thesis.pdf.
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This project explored the biochemistry of non-healing wounds, with aims of expanding the current knowledge on their associated protein profiles. Changes in the abundance levels of proteins within wound fluids were examined in relation to best-practice treatments, including compression therapy, and wound condition, including infection status and disease burden. A complex statistical methodology was developed to analyse wound proteomic mass spectrometry data. This approach identified a suite of significant and clinically relevant protein targets. These findings may benefit wounds research and clinical practice, as they offer insight into the biochemical impact of best-practice care and the effect on wound healing.
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Tounsi, Rami. "Comportement des structures en nids d'abeilles sous sollicitations dynamiques mixtes compression/cisaillement et effet de l'orientation des cellules." Phd thesis, Université de Valenciennes et du Hainaut-Cambresis, 2014. http://tel.archives-ouvertes.fr/tel-01002421.
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Les nids d'abeille d'aluminium combinent légèreté et grande capacité d'absorption d'énergie. Ils sont alors de plus en plus utilisés dans les secteurs du transport (automobile, aéronautique ...) pour contribuer conjointement à l'allègement structural et à la sécurité. Dans cette thèse, le comportement à l'écrasement des nids d'abeille est étudié en tenant compte de l'effet combiné de l'angle d'orientation dans le plan des cellules, de l'angle de chargement et de la vitesse de sollicitation, que la littérature ne relate pas. Un dispositif de chargement mixte compression/cisaillement est conçu pour mener l'étude expérimentale. L'analyse des résultats porte sur le pic initial d'effort, le plateau d'effort, ainsi que sur les modes de déformation. Les résultats montrent une augmentation de la résistance sous sollicitation dynamique dépendante de l'angle de chargement Ψ. Elle devient moins significative quand l'angle de chargement augmente jusqu'à atteindre un angle critique. Pour Ψ > Ψcritique, les réponses quasi-statiques sont même plus élevées que les réponses dynamiques. Une étude numérique est alors entreprise. Elle permet de comprendre ce phénomène qui est imputé aux mécanismes de déformation locaux des cellules. Les résultats numériques montrent également que l'effet de l'angle d'orientation □ dans le plan est plus prononcé sur la force tangentielle que sur la force normale, que cela influence également les modes d'effondrement et donc la réponse mécanique. Ces simulations numériques, couplées aux résultats expérimentaux, permettent alors de dissocier les composantes normale et tangentielle de la réponse des nids d'abeille et d'identifier les paramètres d'un critère macroscopique de résistance exprimé en fonction de la vitesse d'impact, de l'angle de chargement et de l'angle d'orientation dans le plan. Finalement, dans le but de réduire le coût des simulations numériques, un modèle élément fini (EF) réduit basé sur un critère de périodicité tenant compte de l'angle d'orientation dans le plan est proposé et son domaine de validité est évalué.
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Mascolo, Rafael. "Concreto usinado : análise da variação da resistência à compressão e de propriedades físicas ao longo da descarga do caminhão betoneira." reponame:Biblioteca Digital de Teses e Dissertações da UFRGS, 2012. http://hdl.handle.net/10183/75771.
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A crescente utilização do concreto, que é o produto mais fabricado no mundo em termos de volume, somada à pressão do mercado por redução de custos com manutenção das exigências mínimas para segurança do projeto, tem impacto direto na importância e necessidade do controle de qualidade do material. Para concretos usinados, predominantes em grandes centros urbanos, as normas do país preconizam a não utilização dos 15% iniciais e finais do volume total de concreto do caminhão betoneira para fins de ensaio. No entanto, devido a maior facilidade e agilidade, é constatada como prática comum nos canteiros de obra da região a coleta de amostras logo da primeira porção de concreto descarregado. Considerando tal procedimento, fora do padrão preconizado por norma, somado à ausência de normatização para aferição da qualidade do misturador e uniformidade da mistura do concreto e a importância dos ensaios de controle de qualidade dos concretos perante a segurança das estruturas, a presente pesquisa tem como objetivo analisar as variações de resistência à compressão e de propriedades físicas do concreto ao longo da descarga da mistura em caminhão betoneira. A fim de atingir a meta proposta, realizaram-se coletas de amostras em cinco pontos distintos, ao longo da descarga do concreto do caminhão betoneira, para cada um dos 65 lotes (amassadas) avaliados, considerando três diferentes traços de concreto. Para cada ponto de coleta foram avaliados a resistência à compressão, o abatimento de tronco de cone e o teor de agregado graúdo. Estatisticamente, foi constatado que há amassadas em que a variação do ponto de coleta influencia na resistência à compressão, no entanto não se pode afirmar o mesmo considerando critérios da ABECE, adotados como parâmetro de análise na falta de normatização específica para o tema. Não houve a formação de um perfil representativo das variações de resistência conforme o ponto de coleta, diferentemente do teor de agregado graúdo, em que se pode visualizar claramente um perfil em que há concentração de brita nos pontos extremos, início e final da coleta. Em relação à consistência, de modo geral, houve uma redução do ponto inicial ao final, dentro dos limites de indicados por norma.The crescent utilization of concrete which in terms of volume, is the most produced product in the world, added to the pressure of the market to reduce the costs and maintenance of the safety minimum requirements of a project, make a direct impact on the material quality control’s importance and necessity. For ready-mixed concrete, mostly seen in large urban centers, the initial and final 15% usage of its total volume is not recommended by the country standards for test purposes. However, due to the ease, it is a common practice in construction sites of the region to collect samples once the first portion of the concrete is unloaded. Taking into account such procedure, which does not meet the standards recommended, added to the lack of standardization to assess the quality of the concrete mixer, the uniformity of the concrete mixture and the importance of the quality control tests of concrete under the safety of structures, the purpose of this research is to analyze the variations of the concrete strength when compressed and its physical properties along the discharge of the mixture made in a mixer truck. In order to achieve the proposed goal, there were sampling carried out at five different points along the discharge from the concrete mixer truck, for each of the 65 lots (batches) analyzed, considering three different types of concrete. Each sampling collected was analyzed by going through a slump test, compression strength and granulometry analysis. Statistically, it was proven that the sample point collection variation of some of the batches influences the compression strength, on the other hand the same cannot be found considering the ABECE criteria, used as analysis parameter in the absence of specific regulations for the subject. No representative profile of resistance variations based on the sample collection point was formed, in contrast to the coarse aggregate content, in which profile can be clearly seen a concentration of gravels at the extreme points, at the commencement and the end of the sample collection. Regarding its consistency, on the whole, there was a reduction from the initial and to the end point, respecting the regulations standards.
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Mills, Austin Shelley. "The Structural Suitability of Tensegrity Aircraft Wings." University of Dayton / OhioLINK, 2020. http://rave.ohiolink.edu/etdc/view?acc_num=dayton1590172090108379.
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Naber, Logan A. "High Pressure Ratio Compressor Performance Design and Optimization." University of Cincinnati / OhioLINK, 2021. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1626357000628287.
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Arnold, Samantha. "Comparative evaluation of the compressive strength surface hardness and porosity of a selection of capsule-mixed versus hand-mixed Glass lonomer cements." Diss., University of Pretoria, 2019. http://hdl.handle.net/2263/76731.
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Introduction: Glass ionomers are available in sets of powder and liquid constituents, which are dispensed using a scoop and dropper bottle system prior to hand-mixing by an operator. Glass ionomers are also available in capsulated form, which is mixed in a suitable mechanical mixing machine prior to clinical use. Capsulation enables uniform proportioning of the powder and liquid. In this context, mixing time will be correct as an automated process is utilised, resulting in a cement mixture that is optimal and reproducible, with minimal air entrapment. Manufacturers promote the capsulated form as being time saving, and easy to dispense, with more accurate adaptation because of the use of an applicator to place the material. Aim: The aim of this in vitro study was to compare the performance of hand-mixed glass ionomer materials with their capsule-mixed equivalents in terms of compressive strength, surface hardness and porosity. Materials and Methods: Four groups of 10 cylindrical specimens were manufactured for each of the four specified hand-mixed posterior glass ionomers for each test that was performed: Riva Self Cure (RSCH) (SDI Limited); GC Fuji IX GP (FIXH) (GC Corp); Ketac Universal (KUH) (3M ESPE) and Ketac Molar Easymix (KMH) (3M ESPE). Similarly, four groups of 10 cylindrical specimens were manufactured for each of the four equivalent capsule-mixed posterior glass ionomers for each test that was performed: Riva Self Cure (RSCC) (SDI Limited); GC Fuji IX GP (FIXC) (GC Corp); Ketac Universal Aplicap (KUC) (3M ESPE) and Ketac Molar Aplicap (KMC) (3M ESPE). The compressive fracture strength of each specimen was determined after 24 hours using a universal testing apparatus. A compressive load of
1 mm/min was applied to the 6 mm long axis of each specimen. The load to fracture was recorded and the compressive fracture strength was calculated. Within one hour after compressive strength testing, a selection of fragments from each specimen was examined by Scanning Electron Microscope (SEM). Fragments were vacuum gold-sputter-coated prior to SEM examination. The fragments were observed at an operating voltage of 10kV, and over a range of magnifications to investigate crack propagation. The surface hardness of each specimen was measured with a digital micro-hardness tester with Vickers diamond indenter. The indenter was set at a load of 500mN at five predetermined regions of each specimen, with a dwell-time of five seconds. The five readings for each specimen were computed and the mean VHN in N/mm2 for each specimen was determined. Each specimen was observed and analysed for porosity using Micro-CT. Three-dimensional reconstructions were made of each specimen and the number of voids per volume (mm3) of specimen, the total volume of voids (mm3) per volume of specimen and the volume percentage of voids per volume of specimen were calculated. Results: RSCH and RSCC showed statistically significant differences when compressive strength (p=0.027), volume of voids (p=0.005) and volume percentage of voids (p=0.005) were compared. No statistically significant differences were found between RSCH and RSCC when surface hardness (p=0.124) and number of voids (p=0.221) were compared. When compressive strength (p=0.254) and number of voids (p=0.210) of FIXH and FIXC were compared, no statistically significant differences were found. Statistically significant differences were found when surface hardness (p=0.031), volume of voids (p<0.001) and volume percentage of voids (p<0.001) of FIXH and FIXH were compared. No statistically significant difference was found when compressive strength (p=0.090) of KUH and KUC were compared. Statistically significant differences were found when surface hardness (p<0.001), number of voids (p<0.001), volume of voids (p=0.004) and volume percentage of voids (p=0.004) of KUH and KUC were compared. Statistically significant differences were found between KMH and KMC when compressive strength (p<0.001), surface hardness (p=0.006), number of voids (p=0.001), volume of voids (p=0.010) and volume percentage of voids (p=0.010) were compared. Conclusion: The current study suggests that RSCC is more advantageous for clinical use compared to RSCH. The results as to whether the capsule-mix or the hand-mix product are superior for the examined properties for GC Fuji IX GP are inconclusive. KUC surpassed KUH in tests performed and is therefore recommended for clinical use. KMC out-performed KMH in all tests conducted, and is therefore advocated for use in clinical practice.Dissertation (MSc)--University of Pretoria, 2019.
Community Dentistry
MSc
Unrestricted
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Cevik, Mert. "Desifn And Optimization Of A Mixed Flow Compressor Impeller Using Robust Design Methods." Master's thesis, METU, 2009. http://etd.lib.metu.edu.tr/upload/12611105/index.pdf.
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This is a study that is focused on developing an individual design methodology for a centrifugal impeller and generating a mixed flow impeller for a small turbojet engine by using this methodology. The structure of the methodology is based on the design, modeling and the optimization processes, which are operated sequentially. The design process consists of
engine design and compressor design codes operated together with a commercial design code. Design of Experiment methods and an in-house Neural Network code is used for the modeling phase. The optimization is based on an in-house code which is generated based on multidirectional search algorithm. The optimization problem is constructed by using the inhouse parametric design codes of the engine and the compressor. The goal of the optimization problem is to reach an optimum design which gives the best possible combination of the thrust and the fuel consumption for a small turbojet engine.
The final combination of the design parameters obtained from the optimization study are used in order to generate the final design with the commercial design code. On the last part of the thesis a comparison of the final design and a standard radial flow impeller is made in order to clarify the benefit of the study. The results have been showed that a mixed flow
compressor design is superior to a standard radial flow compressor in a small turbojet application.
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Yildirim, G., A. Kul, E. Özçelikci, M. Sahmaran, A. Aldemir, D. Figueira, and Ashraf F. Ashour. "Development of Alkali-Activated Binders froRecycled Mixed Masonry-originated Waste." Elsevier, 2020. http://hdl.handle.net/10454/17960.
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YesIn this study, the main emphasis is placed on the development and characterization of alkali-activated binders completely produced by the use of mixed construction and demolition waste (CDW)-based masonry units as aluminosilicate precursors. Combined usage of precursors was aimed to better simulate the real-life cases since in the incident of construction and demolition, these wastes are anticipated to be generated collectively. As different masonry units, red clay brick (RCB), hollow brick (HB) and roof tile (RT) were used in binary combinations by 75-25%, 50-50% and 25-75% of the total weight of the binder. Mixtures were produced with different curing temperature/periods and molarities of NaOH solution as the alkaline activator. Characterization was made by the compressive strength measurements supported by microstructural investigations which included the analyses of X-ray diffraction (XRD) and scanning electron microscopy with energy-dispersive X-ray spectroscopy (SEM/EDX). Results clearly showed that completely CDW-based masonry units can be effectively used collectively in producing alkali-activated binders having up to 80 MPa compressive strength provided that the mixture design parameters are optimized. Among different precursors utilized, HB seems to contribute more to the compressive strength. Irrespective of their composition, main reaction products of alkali-activated binders from CDW-based masonry units are sodium aluminosilicate hydrate (N-A-S-H) gels containing different zeolitic polytypes with structure ranging from amorphous to polycrystalline.
The full-text of this article will be released for public view at the end of the publisher embargo on 24 Jul 2021.
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Esqueda, Merino Donovan Manuel. "Contrôle/Commande avancé pour l'optimisation du confort thermique d'un véhicule électrifié." Phd thesis, Supélec, 2013. http://tel.archives-ouvertes.fr/tel-00969132.
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Dans cette thèse nous développons des structures de supervision permettant de définir des consignes optimales pour des actionneurs thermiques, ainsi que des stratégies de commande appropriées pour le pilotage d'une pompe à chaleur (PAC). Pour répondre à ces objectifs, plusieurs étapes ont été réalisées :- Modélisation orientée commande d'une PAC réversible, des thermistances, et de l'environnement permettant de les lier à l'intérieur de l'habitacle. Des modèles physiques ont été définis et intégrés dans une plateforme du type Model-in-the-Loop pour permettre a posteriori la validation des stratégies de commande et d'optimisation. - Commande d'une PAC. La linéarisation du modèle de PAC autour de certains points de fonctionnement a permis le développement de la commande de l'actionneur principal. La structure de commande proposée permet de prendre en compte, en boucle fermée, des contraintes d'état et d'entrée du système. Les performances de cette structure ont été analysées en considérant successivement des régulateurs principaux de type PI et Hinf. Enfin, des algorithmes réalisant le pilotage d'un actionneur secondaire du système ont été également proposés. - Optimisation des actionneurs thermiques. L'utilisation combinée de thermistances et de la PAC présente des avantages en termes de réduction de la consommation énergétique et/ou du maintien de la puissance thermique demandée dans des conditions aux limites de fonctionnement. Le problème d'optimisation a été résolu en deux temps : des solutions hors-ligne ont été obtenues par résolution d'un problème mixte en nombre entier avec modèle prédictif, puis utilisées pour déduire des stratégies embarquables sur le véhicule.
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Annear, M. J. ""They're not including us!" : neighbourhood deprivation and older adults' leisure time physical activity participation." Diss., Lincoln University, 2008. http://hdl.handle.net/10182/468.
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Population ageing and the tendency for older adults to have poorer health status than younger adults have raised concerns about potential increases in the number of elderly suffering disease and disability. Significantly, many health problems experienced in later life are associated with the onset of a more sedentary lifestyle. Increasing older adults' participation in leisure time physical activity (henceforth LTPA) offers an opportunity to reduce the prevalence of preventable morbidity in later life and offset a potential burden of ageing on the public health sector. As a forerunner to the development of strategies to increase older adults' LTPA participation, researchers have investigated the intrapersonal, interpersonal and, to a lesser extent, environmental influences on this health behaviour. Recent findings from studies of the adult population have suggested that neighbourhood deprivation, a measure of the socioeconomic conditions of small areas, may significantly influence LTPA participation. Extending previous findings, this research investigated how neighbourhood deprivation influenced older adults' LTPA participation. A total of 63 older adults were recruited from high- and low-deprivation neighbourhoods in Christchurch, New Zealand. Neighbourhoods were selected because of their relative positions on the New Zealand Deprivation Index and were characterised by the researcher as "East-town", a neighbourhood of high deprivation, and "West-town", a neighbourhood of low deprivation. The research incorporated a cross-sectional, comparative and mixed-methods approach. The methods of enquiry employed in this research included a recall survey, Q method, and semi-structured interviewing. Each method addressed a different aspect of the primary research question and provided data that was used in the creation of an integrated model depicting the influence of neighbourhood deprivation on older adults' LTPA participation. The results derived from the three research methods showed that older adults from the low-deprivation neighbourhood of West-town participated in LTPA more frequently than older adults from the high-deprivation neighbourhood of East-town. East-town was identified as having many physical and social environmental constraints to LTPA and comparatively few facilitators. Alternatively, West-town was found to have many physical and social environmental facilitators to LTPA and relatively few constraints. Neighbourhood attributes which appeared to influence older adults' LTPA participation included appropriateness of leisure provision, neighbourhood attractiveness, walkability, traffic, and perceptions of crime and antisocial behaviour. One implication of this research is that environmental interventions should be considered in attempts to engage older adults in LTPA for health purposes, particularly in high-deprivation neighbourhoods.
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Olekambainei, Arip-Kituyan Emmanuel. "The influence of moulding moisture content on the engineering properties of aggregate-lime-natural pozzolan mixes." Diss., Pretoria : [s.n.], 2004. http://upetd.up.ac.za/thesis/available/etd-06092005-094814.
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Dušek, Libor. "Dvojitě vyvážený směšovač – laboratorní přípravek." Master's thesis, Vysoké učení technické v Brně. Fakulta elektrotechniky a komunikačních technologií, 2008. http://www.nusl.cz/ntk/nusl-217711.
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The aim of this work was double-balanced mixer implementation, which will be used like laboratory equipment. This thesis deals with design of the double-balanced mixer from first theoretical principles to a practical design of a laboratory equipment. For the practical design the integrated mixer SA612 was used. Input signal to the mixer up to 500 MHz frequency can be used. For required operation external oscillator and fifth-order low pass filter were constructed. Oscillator was designed for fixed frequency 32 MHz. Fifth-order low pass filter was inserted between the mixer and the oscillator, because of filtering higher harmonics. The second aim of the work was measuring double-balanced mixer basic parameters, such as Compression Point (P-1dB) and Intercept Point (IP3). For the IP3 measurement, another one device was required. It consists of the power combiner for mixing two frequency close signals and third-order bandpass filter, which selects required frequency band. Finally, the laboratory equipment was fabricated and its real parameters were measured.
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Pokluda, Radim. "Stavební recykláty pro stmelené směsi vozovek." Master's thesis, Vysoké učení technické v Brně. Fakulta stavební, 2013. http://www.nusl.cz/ntk/nusl-226040.
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In the theoretical part of the thesis are generally characterized hydraulically bound mixtures, their types, classification systems, manufacturing technology and the laying. There are also described experiences from abroad with the use secondary and recycled materials in hydraulically bound mixtures. The practical part deals with the experimental verification of the possibility of the use of secondary materials in hydraulically bound mixtures in construction of road infrastructure. In road laboratory Institute of road structures Brno university of technology was the five proposed mixtures, an assessment of their parameters with regard to the possibility of using these mixtures in the road sub-base layers. The work is also aimed at comparison of results elasticity modules reached laboratory testing and experimental measurements on road polygon.
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Chan, WenYen. "MIXED PHASE COMPRESSION HIGH EFFICIENCY HEAT PUMP." Thesis, 2014. http://hdl.handle.net/10012/8292.
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The objective of this thesis is the design and realization of a higher efficiency air source heat pump. The improved pump???s operating cost must rival the cost of heating with natural gas, while incurring a minimal increase in the capital cost of the pump. A COP greater than 4 at ???15C ambient is needed to achieve this goal. During winter season testing a COP of 4.25 +/- 0.11 was observed. This tracks well with a predicted COP of 4.4 and also against a commercial system with a claimed COP between 2.1 and 3.0.
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Alexander, Derrick. "Hypersonic mixed-compression inlet shock-induced combustion ramjets." 2006. http://link.library.utoronto.ca/eir/EIRdetail.cfm?Resources__ID=449817&T=F.
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Villaverde, Jocelyn, and 喬絲茹. "Data Compression and Mixed Signal ASIC Design for Energy-efficient Low Power Applications." Thesis, 2017. http://ndltd.ncl.edu.tw/handle/50156857704852533590.
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博士中原大學
電子工程研究所
105
Huge data processing contributes many factors in wireless sensor network (WSN) such as network traffic and energy constraint. Wearable devices have become widely used to monitor body signals for long-term health care and home care applications. They detect vital signals through physiological sensors and then transmit them to a cloud database for evaluation and monitoring purposes through wireless communication systems. These wearable devices also need to pay attention their power consumption. This dissertation is divided into parts, applying two different data compression techniques for reducing the power consumption of WSN and wearable device. Using compressive sensing a new technique in data acquisition which reduced the required sampling rate to reconstruct the original signal will therefore lessen the power consumption of the WSN. The primary objective of the design is to reduce the power consumption on wireless system network by maximizing the data packet payloads while minimizing the transmission activity of the Wireless Sensor Network. The sensor and receiver node consume more power when transmission of data is taking place. Fast Fourier Transform (FFT) will determine the sparsity of the signal; the measurement matrix contains the large coefficients and orthogonal matching pursuit was used for the recovery of the original signals. Matlab was used to simulate the results of the compressive sensing algorithm. On the other hand, a smart analog-to-digital converter (ADC) was realized by a mixed-signal application-specific integrated circuit (ASIC) based on adaptive resolution and lossless compression techniques for electrocardiogram (ECG) signal monitoring. The sampling clock for the ADC can be adaptively selected according to the characteristic of the signals. The lossless encoder consists of trend forecasting and entropy coding modules. The transmission data rate was decreased efficiently by adaptive resolution and lossless compression techniques. The chip aims to meet the low power consumption for the design because it reduced the signal transmission rate and maintained high-quality ECG signal detection. The mixed-signal ASIC design was realized using a 0.18 μm CMOS process with a total power consumption of 78.8 µW when operating at 1 kHz and a total chip area of 850 × 850 μm2.
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Chiao, Yu-Hua, and 焦郁華. "Mixed PDE Based Methods with Adaptive Block Truncation Coding for Image De-noising and Compression." Thesis, 2011. http://ndltd.ncl.edu.tw/handle/78626738415621210245.
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碩士國立中興大學
應用數學系所
99
In this thesis, we propose an adaptive block truncation coding method (ABTC) for image compression. For achieving a better image quality, we propose a novel algorithm by a mixture of a upwind finite difference for solving a time dependent convection diffusion equation and the ABTC algorithm to remove the image noise. The numerical results show that our proposed methods are effectively remove the noise, and preserves the edge information well during the image compression process.
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Wu, Ming-Feng, and 吳明峰. "A Wavelet Multiresolution Compression Technique for 3D Stereoscopic Image Sequence Based on Mixed-Resolution Psychophisical Experiments." Thesis, 1996. http://ndltd.ncl.edu.tw/handle/88898130331613320380.
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碩士國立交通大學
電信工程研究所
84
Three-dimensional visual communications, made through the use of stereoscopiimages, are able to achieve total display realism. In order to create a 3-D system with two images ( left and right) that must be transmitted simultaneously, the large amount of information contained in the images must be reduced, and an efficient coding appropriate for stereoscopic images developed. Stereoscopic image sequence compression involves the exploitation of the spatial redundancy between the left and right image fames to achieve the compression ratio higher than that are by the independencompression of the two frames. In order to further achieve the higher compression ratio, in this paper, we empoly the mixed-resolution psychophysical experiments to the stereo image compression. The experiments have shown that a stereo image pair with one high resolution image and one lower resolution image is sufficient to provide good stereoscopic depth perception. Thus, one image sequence is compressed independent of the other sequence using the motion compensation, while the other sequence is estimated at a lower resolution from this stream using the low resolution disparity compensation. To implement the mixed-resolution coding, a wavelet multiresolution framework has been adopted to facilitate such an estimation of motion and disparity vectors at different resolutions. Experimental results indicate that the compression ratio for a typical stereoscopic image sequence is about 90, without any significant loss in the perceived 3D stereoscopic image quality.
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Bittle, Joshua. "Two-stage Ignition as an Indicator of Low Temperature Combustion in a Late Injection Pre-mixed Compression Ignition Control Strategy." 2010. http://hdl.handle.net/1969.1/ETD-TAMU-2010-12-8945.
Full textAbstract:
Internal combustion engines have dealt with increasingly restricted emissions requirements. After-treatment devices are successful in bringing emissions into compliance, but in-cylinder combustion control can reduce their burden by reducing engine out emissions. For example, oxides of nitrogen (NOx) are diesel combustion exhaust species that are notoriously difficult to remove by after-treatment. In-cylinder conditions can be controlled for low levels of NOx, but this produces high levels of soot potentially leading to increased particulate matter (PM). The simultaneous reduction of NOx and PM can be realized through a combustion process known as low temperature combustion (LTC).
In this study, the typical definition of LTC as the defeat of the inverse relationship between soot and NOx is not applicable as a return to the soot-NOx tradeoff is observed with increasing exhaust gas recirculation (EGR). It is postulated that this effect is the result of an increase in the hot ignition equivalence ratio, moving the combustion event into a slightly higher soot formation region. This is important because a simple emissions based definition of LTC is no longer helpful. In this study, the manifestation of LTC in the calculated heat release profile is investigated.
The conditions classified as LTC undergo a two-stage ignition process. Two-stage ignition is characterized by an initial cool-flame reaction followed by typical hot ignition. In traditional combustion conditions, the ignition is fast enough that a cool-flame is not observed. By controlling initial conditions (pressure, temperature, and composition), the creation and duration of the cool-flame event is predictable. Further, the effect that injection timing and the exhaust gas recirculation level have on the controlling factors of the cool-flame reaction is well correlated to the duration of the cool-flame event. These two results allow the postulation that the presence of a sufficiently long cool-flame reaction indicates a combustion event that can be classified as low temperature combustion. A potential method for identifying low temperature combustion events using only the rate of heat release profile is theorized.
This study employed high levels of EGR and late injection timing to realize the LTC mode of ordinary petroleum diesel fuel. Under these conditions, and based on a 90 percent reduction in nitric oxide and no increase in smoke output relative to the chosen baseline condition, a two part criteria is developed that identifies the LTC classified conditions. The criteria are as follow: the combustion event of conventional petroleum diesel fuel must show a two-stage ignition process; the first stage (cool-flame reaction) must consume at least 2 percent of the normalized fuel energy before the hot ignition commences.
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Li, Li. "Model Selection via Minimum Description Length." Thesis, 2011. http://hdl.handle.net/1807/31834.
Full textAbstract:
The minimum description length (MDL) principle originated from data compression literature and has been considered for deriving statistical model selection procedures. Most existing methods utilizing the MDL principle focus on models consisting of independent data, particularly in the context of linear regression. The data considered in this thesis are in the form of repeated measurements, and the exploration of MDL principle begins with classical linear mixed-effects models. We distinct two kinds of research focuses: one concerns the population parameters and the other concerns the cluster/subject parameters. When the research interest is on the population level, we propose a class of MDL procedures which incorporate the dependence structure within individual or cluster with data-adaptive penalties and enjoy the advantages of Bayesian information criteria. When the number of covariates is large, the penalty term is adjusted by data-adaptive structure to diminish the under selection issue in BIC and try to mimic the behaviour of AIC. Theoretical justifications are provided from both data compression and statistical perspectives. Extensions to categorical response modelled by generalized estimating equations and functional data modelled by functional principle components are illustrated. When the interest is on the cluster level, we use group LASSO to set up a class of candidate models. Then we derive a MDL criterion for this LASSO technique in a group manner to selection the final model via the tuning parameters. Extensive numerical experiments are conducted to demonstrate the usefulness of the proposed MDL procedures on both population level and cluster level.
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Yu, Zhuizhuan. "Digitally-Assisted Mixed-Signal Wideband Compressive Sensing." Thesis, 2011. http://hdl.handle.net/1969.1/ETD-TAMU-2011-05-9328.
Full textAbstract:
Digitizing wideband signals requires very demanding analog-to-digital conversion (ADC) speed and resolution specifications. In this dissertation, a mixed-signal parallel compressive sensing system is proposed to realize the sensing of wideband sparse signals at sub-Nqyuist rate by exploiting the signal sparsity. The mixed-signal compressive sensing is realized with a parallel segmented compressive sensing (PSCS) front-end, which not only can filter out the harmonic spurs that leak from the local random generator, but also provides a tradeoff between the sampling rate and the system complexity such that a practical hardware implementation is possible. Moreover, the signal randomization in the
system is able to spread the spurious energy due to ADC nonlinearity along the signal bandwidth rather than concentrate on a few frequencies as it is the case for a conventional ADC. This important new property relaxes the ADC SFDR requirement when sensing frequency-domain
sparse signals.
The mixed-signal compressive sensing system performance is greatly impacted by the accuracy of analog circuit components, especially with the scaling of CMOS technology. In this dissertation, the effect of the circuit imperfection in the mixed-signal compressive
sensing system based on the PSCS front-end is investigated in detail, such as the finite settling
time, the timing uncertainty and so on. An iterative background calibration algorithm based on LMS (Least Mean Square) is proposed, which is shown to be able to effectively calibrate the error due to the circuit nonideal factors.
A low-speed prototype built with off-the-shelf components is presented. The prototype is able to sense sparse analog signals with up to 4 percent sparsity at 32 percent of the Nqyuist rate. Many practical constraints that arose during building the prototype such as circuit nonidealities are addressed in detail, which provides good insights for a future high-frequency integrated
circuit implementation. Based on that, a high-frequency sub-Nyquist rate receiver exploiting the parallel compressive sensing is designed and fabricated with IBM90nm CMOS technology, and measurement results are presented to show the capability of wideband
compressive sensing at sub-Nyquist rate. To the best of our knowledge, this prototype is the first reported integrated chip for wideband mixed-signal compressive sensing. The proposed prototype achieves 7 bits ENOB and 3 GS/s equivalent sampling rate in simulation assuming a 0.5 ps state-of-art jitter variance, whose FOM beats the FOM of the high speed state-of-the-art Nyquist ADCs by 2-3 times.
The proposed mixed-signal compressive sensing system can be applied in various fields. In particular, its applications for wideband spectrum sensing for cognitive radios and spectrum analysis in RF tests are discussed in this work.
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TAI, KUO YU, and 郭宇泰. "The Compressive Strength of Soil Mixed with HSC301." Thesis, 2009. http://ndltd.ncl.edu.tw/handle/63034882649947708858.
Full textAbstract:
碩士明新科技大學
營建工程與管理研究所
97
In this study, soil at the different coefficient of uniformity (CU) were added at different proportion (5%, 10%, 15%, 20%) and the Ground Improvement Admixture (HSC301) conditioner and Type I of the soil cement mixture by mixing. Firstly, the experimental value of the soil PH test to gain a better understanding of soil and examine if the pH is greater than 5.3. According to ACI study, if cement solidified soil PH value exceeds 5.3, it will help to enhance the cement hydration, then investigate the relationship between compressive strength with different curing periods of 3 days, 7 days, 14 days, 28 days separately. Additionally, it is required to examine inter-relationship of the pH value, best water maximum and dry density of soil versus HSC301 and soil versus cement modifier The results showed that soil at the different coefficient of uniformity (CU) mixes with the Ground Improvement Admixture at the different proportion mixtures and type I cement, its compressive strength increases with the ages; and also increases along with the geological of modifier and type I cement increases. The compressive strength of the soil- Ground Improvement Admixture mixture is higher than that of the soil-cement mixture. PH value of the soil mixture increases along with the Ground Improvement Admixture and Type I cement increases; and the compressive strength of soil mixture also increases with the PH value. Moreover, the optimum moisture content for the soil - geology modifier mixture and for the soil - cement mixture increases with reducing of the Ground Improvement Admixture and Type I cement, otherwise the maximum dry density had reverse results.
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Chang, Shih Hung, and 張世鴻. "Design and Analysis of a Mixed-Flow Type Compressor." Thesis, 1999. http://ndltd.ncl.edu.tw/handle/41873774770763387449.
Full textAbstract:
碩士逢甲大學
機械工程學系
87
The paper of the proposed project is to design P60S mixed-flow compressor and applied the current quasi and fully 3-D turbomachinery flow analysis to assist the P60S compressor design. The proposed research aims to integrate the advanced mixed-flow compressor flow analysis system for the use of small gas turbine power and propulsion systems. To assist the P60S compressor design, the analysis system has incorporated the current available turbomachinery flow analysis tools used in gas turbine industry. The IDEAS will generate the finite element mesh for structure analysis in ANSYS while the solid modeling of compressor component is CAD in IDEAS. The unified database developed has been able to generate the input of the analysis tools both from NREC compressor design system and BPAD blade design system. This interaction will reduce the iteration time between compressor design and analysis. The presented results include the P60S mixed-flow compressor design parameters, lay-out and CAD modeling, quasi 3-D and fully 3-D flow analysis for the impeller, 1st and 2nd diffuser and deswirl vane, and structural analysis on ANSYS.
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Dung, Jian-Shin, and 董建鑫. "Analysis for compressive strength of cement mortar mixed with MSWI fly ash slag and admixtures." Thesis, 2008. http://ndltd.ncl.edu.tw/handle/32598155756890295296.
Full textAbstract:
碩士國立聯合大學
土木與防災工程學系碩士班
96
The bottom residue and fly ash are produced from municipal solid waste incinerator. Bottom residues can be disposed in landfill and as material for permeable brick. But fly ash was not easy to recycle, because it contains much heavy metal. Although significant achievements in applying fly ash to cement mortar and concrete have been obtained, but the weaker compressive strength at the early curing age is still a problem, and needs to be improved. This study is aimed to improve the weaker compressive strength of the MSWI fly ash slag blended cement mortar at the early curing age. First, we try to add the nano CaCO3 slurry to the cement mortar. Second, we molded the same cement mortar but added nano SiO2 slurry. As aforementioned, the two compressive strength tests had good results in strength improvement. Then we try to use the chemical mechanical polishing (CMP) sludge of the semiconductor industry waste water to replace 0~20 wt.% cement, and to mold the cement mortar specimens for testing. Because the waste sludge contained large amount of SiO2 nano-particles, and the compressive strength test of these specimens had good result. Therefore, for obtaining the highest strength, the experiment design of three levels and four factors (cement, slag, CMP quantity, and water to binder ratio) was selected to have the nine kinds of specimens for testing. The test results revealed the strengths of some kind of specimens were stronger than the ordinary Porterland cement mortar after three days of curing. Thus the early stage compressive strength of MSWI fly ash slag blended cement mortar was improved. Finally, the experimental design for compressive strength was successful and confirmed. The test results showed that the best mixture proportion was w / b = 0.485, cement amount = 80 wt.%, MSWI fly ash slag amount = 17 wt.%, and CMP sludge amount = 13 wt.%, which had the highest compressive strength. The test results revealed that both the MSWI fly ash and CMP sludge cauld be recycled as admixtures to cement mortar, and was good for sustainable environment.
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Liu, Chien-Chin, and 劉建志. "Different mix design of ready-mixed concrete plant and discussion on the compressive strength of cylindrical specimens." Thesis, 2018. http://ndltd.ncl.edu.tw/handle/ktpca9.
Full textAbstract:
碩士國立屏東科技大學
土木工程系所
106
This will be the 210 kg/cm2 strength of premixed concrete materials for study, sampling source for area three qualified ready-mixed concrete plants, batching plant based on different mixture design of tables, making 15 cm times high 30 cm concrete compressive strength cylindrical specimens corresponding values of compressive strength after 28 days of age and statistical analysis and resulting in proportioning of concrete design value and strength factors of variation, and mix design of ready-mixed concrete admixture-related act of rationally and problems, to assess material properties and quality conditions of influence degree of compressive strength of concrete. Finally, through corrective and preventive measures of the process, ready-mixed concrete with stable quality and product positioning to improve efficiency.