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Nabijou, Sharifeh. "Frictional behaviour and fatigue performance of wire ropes bent over small diameter sheaves." Thesis, Imperial College London, 1990. http://hdl.handle.net/10044/1/7453.
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Benini, Brian J. "Tension and Flex Fatigue Behavior of Small Diameter Wires for Biomedical Applications." Cleveland, Ohio : Case Western Reserve University, 2010. http://rave.ohiolink.edu/etdc/view?acc_num=case1269970809.
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Thesis (Master of Sciences)--Case Western Reserve University, 2010Department of Materials Science and Engineering Title from PDF (viewed on 2010-05-25) Includes abstract Includes bibliographical references and appendices Available online via the OhioLINK ETD Center
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Луценко, Владислав Анатолійович, Владислав Анатольевич Луценко, and Vladyslav A. Lutsenko. "Наукові основи вдосконалення термомеханічної обробки катанки для сталевого дроту малого діаметру." Thesis, Запорізький національний технічний університет, 2015. http://eir.zntu.edu.ua/handle/123456789/417.
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Луценко, В.А. Наукові основи вдосконаленнятермомеханічної обробки катанки для сталевого дроту малого діаметру [Текст]: дис. … докт. техн. наук: 05.16.01 : захищена ....: затверджена…. /Луценко Владислав Анатолійович. – Запоріжжя, 2015. – 353 с.UK: Дисертаційна робота присвячена підвищенню в процесі ТМО пластичних властивостей сталевої катанки. Отримана сталева катанка має структуру: високовуглецева – дисперсний перліт із відсутністю замкнутої цементитної сітки, мінімальний зневуглецьований шар, який рівномірно розподілений по периметру; низьковуглецева – рівномірну структуру фериту з мінімальною кількістю перліту; легована – наявність бейніто-мартенситних ділянок до 10% в змішаній структурі. Результати використані на дротових станах ВАТ «БМЗ» та ПАТ «АрселорМіттал Кривий Ріг». Підвищення пластичності катанки забезпечило виготовлення сталевого дроту малого діаметру без проміжної термічної обробки, що дозволило знизити видатковий коефіцієнт металу в середньому на 10%. EN: The dissertation is devoted of increasing in thermo-mechanical processing the plastic properties of steel wire rod. The obtained steel wire rod has the structure: high carbon – the dispersion of perlite without closed cementite net, the minimum depth of equable decarburized layer; low carbon – uniform structure of ferrite with a minimum of perlite; alloy – the occurrence of bainite-martensite areas up to 10% in the mixed structure. The results were used on the rod mills OJSC “Byelorussian steel works” and РJSC “ArcelorMittalKryvyiRih“. The increasing of plasticity provided the production of steel wire of small diameter without intermediate heat treatment, thus reducing the expenditure coefficient of metal by 10% in average. RU: В диссертационной работе решена актуальная научно-техническая проблема – повышение после высокотемпературной прокатки пластических свойств металла путем развития научных основ о влиянии процессов ТМО на структурообразование и качественные характеристики стальной катанки. Установленные закономерности позволили совершенствовать технологию ТМО катанки и при экономии материальных ресурсов обеспечить производство стальной проволоки малого диаметра для металлокорда (в том числе сверхвысокопрочного), высокопрочной бортовой, канатной, легированной сварочной и низкоуглеродистой. Изучена кинетика превращения аустенита непрерывнолитой стали 90 при непрерывном охлаждении и в изотермических условиях. Установлено, что выделения цементита по границам зерен подавляются и полностью отсутствуют при скоростях более 10°С/с и при изотермическом распаде. Определено, что величина эффекта рекалесценции в стали 90 зависит от времени превращения. Установлено, что при ТМО снижение температуры после горячей деформации с 1050…1100°С до 900…950°С в результате принудительного охлаждения при повышении дробности деформации (на 20%) приводит к увеличению пластических свойств высокоуглеродистой стали. Полученная катанка для стальной проволоки, в отличие от традиционной, имеет повышенные пластические свойства. Основу структуры катанки составляет: высокоуглеродистой – сорбитообразный перлит (более 70%) с отсутствием избыточных структур (замкнутой цементитной сетки), минимальный обезуглероженный слой равномерно распределен по периметру; низкоуглеродистой – равномерная структура феррита с минимальным количеством пластинчатого перлита; легированной – наличие бейнито-мартенситных участков до 10% в смешанной структуре. Повышены требования к микроструктуре и свойствам высокоуглеродистой катанки и проволоки, которые отражены в изменении №11 к ЗТУ 840-03-2006 «Катанка стальная сорбитизированная для металлокорда, бортовой проволоки и проволоки для рукавов высокого давления» и ТУ У 276.3-23365425-638.2008 «Проволока стальная термически обработанная». Результаты использованы на ПАО «АрселорМиттал Кривой Рог» при разработке СТИ 228-112-2008 «Производство катанки из легированных сталей для сварочной проволоки ответственного назначения», изменения №3 к режимам охлаждения проката в потоке проволочного стана 150-1 СПЦ-1. Разработаны и внедрены на ОАО «БМЗ» режимы ТМО стальной катанки, в том числе для сверхвысокопрочной проволоки и металлокордапо ЗТУ 840-03-2006 (Изменения к ТК 840-П13-01-2002 и ТК 840-П3-01-2007 на режимы двухстадийного охлаждения катанки различного марочного сортамента в потоке стана 150). Повышение пластичности после высокотемпературной прокатки обеспечило изготовление стальной проволоки малого диаметра различного назначения без промежуточной термической обработки с сохранением требуемых конечных характеристик. Катанка, изготовленная по новому режиму ТМО, переработанная на проволоку малого диаметра, имеет лучшую технологичность в сравнении с базовой. Так, при производстве высокопрочногометаллокорда обрывность снизилась на 34%, а сверхвысокопрочного – на 23%. Освоение усовершенствованных режимов ТМО позволило снизить расходный коэффициент металла в среднем на 10%. Общий фактический экономический эффект от внедренных новых технологических решений составляет 31,7 миллиона гривен, доля автора – 4,44 миллиона гривен.
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Rouse, B. D. "Modelling of small diameter hydrocyclones." Thesis, University of Nottingham, 1986. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.371290.
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Caswell, Robert J. "Viscosity effects in small diameter hydrocyclones." Thesis, University of Nottingham, 1990. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.278416.
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Clayton, J. S. "Small diameter hydrocyclones in coal preparation." Thesis, University of Nottingham, 1985. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.371274.
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Arief, Melissa Suen. "Human Tissue Engineered Small Diameter Blood Vessels." Yale University, 2010. http://ymtdl.med.yale.edu/theses/available/etd-03152010-144428/.
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The engineering of human vascular grafts is an intense area of study since there is crucial need for alternatives to native vein or artery for vascular surgery. This current study sought to prove that a tissue engineered blood vessel (TEBV) 1mm in diameter could be developed from human smooth muscle cells and that endothelial progenitor cells (EPCs) could be cultured and used to endothelialize these grafts. This project had four specific aims: the isolation and characterization of EPCs, the seeding of a novel scaffold with EPCs and exposure to physiologic shear stress in vitro, the development of TEBV from human smooth muscle cells that are strong enough to implant in vivo, and the in vivo implantation of TEBV into the rat aortic model with a comparison of EPC seeded TEBVs pretreated with shear stress and unseeded TEBVs. The results yielded isolation of four EPC lines and a flow system design capable of seeding EPCs onto a novel scaffold with preliminary studies indicating that it is capable of exposing the EPCs to physiologic shear stress, although further studies require more optimization. The development of mechanically strong TEBV was highly successful, yielding TEBVs comparable to native vessels in collagen density and burst pressure, but with much lower compliance. Current implantation studies indicated that unseeded TEBV grafts implanted into the rat aorta without anticoagulation is highly thrombogenic. However, anticoagulation using Plavix may be capable of maintaining graft patency. These TEBVs did not rupture or form aneurysm in vivo and the future completion of the in vivo studies are likely to demonstrate the high potential of these grafts.
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Derham, Chris. "Tissue engineering a small diameter vascular graft." Thesis, University of Leeds, 2010. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.535102.
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McLean, Michael B. "Dynamic performance of small diameter tunnel thrusters." Thesis, Monterey, California. Naval Postgraduate School, 1991. http://hdl.handle.net/10945/28132.
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Littlewood, Kim. "Movement of gross solids in small diameter sewers." Thesis, Imperial College London, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.391796.
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Bae, S.-K. "Soil-structure interaction in small-diameter clayware pipelines." Thesis, University of Newcastle Upon Tyne, 1985. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.355848.
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Bukauskas, Aurimas (Aurimas M. ). "New structural systems in small-diameter round timber." Thesis, Massachusetts Institute of Technology, 2015. http://hdl.handle.net/1721.1/99241.
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Thesis: S.B., Massachusetts Institute of Technology, Department of Architecture, 2015.This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.
Cataloged from student-submitted PDF version of thesis.
Includes bibliographical references (page 51).
Trees, when used as structural elements in their natural, round form, are up to five times stronger than the largest piece of dimensioned lumber they could yield. Additionally, these whole-timbers have a lower effective embodied carbon than any other structural material. When combined into efficient structural configurations and joined using specially-engineered connections, whole-timber has the potential to replace entire steel and concrete structural systems in large-scale buildings, bridges, and infrastructure. Whole-timber may be the most appropriate structural solution for a low-carbon and fully renewable future in both developed temperate regions and the developing Global South. To reduce barriers to adoption, including project complexity and cost, a standardized "kit of parts" in whole-timber is proposed. This thesis proposes new designs for the first and most important element of this kit: a structurally independent column in whole-timber. A 20' compound column in whole-timber is prototyped at full-scale. New, simple calculation methods are developed for estimating the buckling capacity of tapered timbers. Based on conservative assumptions, the embodied carbon of whole-timber column systems is shown to be between 30% and 70% lower than conventional steel systems.
by Aurimas Bukauskas.
S.B.
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Beneke, Jeremy Michael. "Small diameter particle dispersion in a commercial aircraft cabin." Thesis, Manhattan, Kan. : Kansas State University, 2010. http://hdl.handle.net/2097/4150.
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Hallman, Christine, Scott Parkinson, and Rex Adams. "Limb: A Mini-Borer for Sampling Small Diameter Trees." Tree-Ring Society, 2006. http://hdl.handle.net/10150/262647.
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The dimensions, manufacture and application of a mini-borer to take 3-mm cores are described. This new instrument seems particularly well-suited to determining ages of saplings in situations where collection of cross-sections and coring with standard increment borers are too destructive, and where node-counting may not be sufficiently accurate. The design has resulted in trouble-free use in the field, and the mini-cores can be stored in the straws, and mounted and sanded in the core mounts used for collections of the standard 4-5-mm increment cores.
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Baguneid, Mohamed. "The development of a tissue-engineered small diameter graft." Thesis, University of Manchester, 2008. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.516820.
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A tissue-engineered small diameter blood vessel was developed by seeding endothelial cells onto a collagen matrix that was cross-linked and contracted by smooth muscle cells onto a polyester scaffold. Endothelial cells (EC) and smooth muscle cells (SMC) were isolated using enzyme dissociation of porcine aorta. Batches of these cells were accredited by immunohistochemical characterisation and functional assay prior to being used in any experiments. Once deemed suitable, they were cryopreserved for later use. Initial experiments determined the optimum SMC and collagen concentrations for producing a cellular rich collagen matrix. The use of a synthetic permanent polyester scaffold provided structural integrity for the developing blood vessel. Dedicated and robust bioreactor vessels and a pulsatile flow circuit were developed to be able to sustain the biologically active tissue and maintain physiological homeostasis. The retention of radiolabelled endothelial cells seeded onto the luminal surface of the grafts was assessed under conditions of high shear stress. The effect of surface modification using a variety of extracellular matrix proteins and low shear stress preconditioning of the SMC matrix was also assessed for its ability to enhance EC retention. Invivo evaluation of these tissue engineered grafts using a porcine model of infrarenal aortic implantation was finally carried out using standard Dacron grafts as controls.
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O'Shea, Phillipa Jane. "Failure mechanisms for small diameter cast iron water pipes." Thesis, University of Southampton, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.326519.
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Camargo, Alexandra. "Propogation of near-limit gaseous detonations in small diameter tubes." Thesis, McGill University, 2009. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=66652.
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In this thesis, detonation limits in small diameter tubes are investigated to further the understanding of the near limit detonation phenomenon. Mixtures with argon dilution (stable detonation) and without dilution (unstable detonation) are used in the experiments. For stable mixture highly diluted with argon where instabilities are not the important propagation mechanism, failure can be attributed to losses to the tube wall. For the stable mixture, the limits obtained experimentally are found to be in good agreement with a quasi-one dimensional ZND theory with flow divergence and have curvature due to boundary layer displacement effect. For detonations in undiluted mixtures (unstable) where instabilities are the principal propagation mechanism, agreement between experiments and ZND theory is not good. For unstable detonations suppression of the instabilities of the cellular detonation due to boundary conditions are thought to be responsible for the failure of the detonation wave. Different near-limit propagation regimes are also observed, e.g. spinning, galloping, stuttering, etc. Based on the present experimental results, an attempt is made to develop an operational criterion for the propagation limits of stable and unstable detonations.Cette étude a pour but d'étudier les limites de propagation de détonations dans de très petits diamètres de tubes. Dans cette recherche, des mélanges hautement dilués avec de l'argon (stables) et des mélanges non-dilués avec de l'argon (instables) sont utilisés. Pour le mélange hautement dilué avec de l'argon, dans lequel les instabilités ne sont pas très présentes et dans lequel l'atténuation de la propagation de la détonation est principalement causée par les pertes de chaleur à la parois, la limite de détonation qui a été obtenue expérimentalement est en accord avec celle obtenue théoriquement par la résolution des équations quasi-stationnaires de la théorie ZND, où une divergence de l'écoulement simule les effets de couche limites à la paroi. Pour les détonations instables dans les mélanges non-dilués avec de l'argon, les régimes pour les différents modes de propagation près des limites de la détonation sont étudiés. Chacun de ces modes de propagation sont analysés attentivement afin de déterminer un critère pour définir les limites de propagation de détonations dans différents mélanges gazeux.
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Weight, Shilo Willis. "A novel wood-strand composite laminate using small-diameter timber." Online access for everyone, 2007. http://www.dissertations.wsu.edu/Thesis/Spring2007/s_weight_050207.pdf.
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Shifera, Dereje. "Two-phase flow boiling in small to micro-diameter tubes." Thesis, Brunel University, 2008. http://bura.brunel.ac.uk/handle/2438/5420.
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This thesis is dedicated to the experimental and theoretical study of flow boiling in small to micro diameter tubes using R 134a. Flow pattern, heat transfer and pressure drop studies were conducted in stainless steel cold drawn tubes with internal diameter 2.88,1.1, and 0.52 mm using an existing facility that was designed with a long term research objective of improving the fundamental understanding of flow boiling in small metallic tubes. The facility was moved to the present location from London South Bank University and re-commissioned before carrying out the experiments. The test sections were heated by a direct passage of alternating current and wall temperatures were measured at 15 axial locations by miniature thermocouples that were directly spotwelded at the tube outer wall. A digital high-speed camera was used to simultaneously observe the flow patterns (during the heat transfer tests) directly at a borosilicate glass tube located immediately downstream of the heat transfer test section. The purpose of the flow visualization study was to support understanding of the heat transfer characteristics and development of flow regime-specific models. The heat transfer and pressure drop data of X. Huo (2005) in the 4.26 and 2.01 mm tubes and the flow visualization results of Chen (2006) for the tubes of diameter 4.26,2.88,2.01, and 1.1 mm were included with the new data in an extensive analysis of flow boiling heat transfer and pressure drop in five vertical tubes with internal diameters 4.26, 2.88,2.01, 1.1 and 0.52 mm. The wide range of tube diameter was chosen to investigate the influence of tube size and possibly identify the threshold where the effect of small or micro diameter effects become significant. In the experiments, parameters were varied in the ranges: mass flux 100 to 700 kg/m2s; heat flux 1.6 to 150 kW/m; pressure 6 to 14 bar; quality up to 0.9 and the inlet temperature was controlled at a subcooling of 1-5K. There was no clear significant difference between the characteristics and magnitude of the heat transfer coefficients in the 4.26 mm and 2.88 mm tubes but the coefficients in the 2.01 and 1.1 mm tube were higher. The heat transfer results suggested that a tube size of about 2 mm might be considered as a critical diameter to distinguish small and conventional tubes. Further differences have now been observed in the 0.52 mm tube. These differences, both in flow patterns and heat transfer, indicate a possible second change from small to micro behaviour at diameters less than 1 mm for R 134a. Also, the results showed axial variations in heat transfer characteristics marking the importance of surface conditions on heat transfer. This calls for a further detail investigation to understand the underlying physics in the initiation of boiling, effect of surface condition on nucleation, and structure of newly emerging flow patterns, particularly in very small tubes. Existing correlations were examined using the results of the five tubes and indicated that these correlations do not predict the present small diameter data to a satisfactory degree. Therefore, two new correlations that take into account both magnitude and characteristic effect of tube diameter have been proposed covering the 4.26 mm-1.1 mm and the smallest 0.52 mm tube, respectively. A detailed comparison was also made with the state-of-the-art flow regime-specific model of Thome et al. (2004) and verified that the mechanistic modelling approach has a promising capability of predicting two phase heat transfer in small diameter tubes, although it still requires further development. Some improvements have been proposed and tested against the current data. Using a similar approach, a new two phase pressure drop model has been proposed and compared with the current data with encouraging results.
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Samman, Fatimah Basem. "Self-assembled functionalised peptides for small-diameter vascular graft applications." Thesis, University of Leeds, 2017. http://etheses.whiterose.ac.uk/19982/.
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Current clinically used small-diameter vascular grafts have been shown to have poor patency rates mainly caused by thrombus formation due to the absence of the anti-thrombogenic endothelium. Studies of novel small-diameter decellularised porcine arteries in large animal models of vascular replacement have also shown poor patency rates. The aim of this study was to develop a series of bioactive self-assembled P11 peptides as surface coatings to enhance re-endothelialisation of decellularised porcine external iliac arteries and potentially mitigate thrombus formation. Porcine external iliac arteries were decellularised and validated for acellularity and in vitro biocompatibility. These acellular scaffolds lacked the natural anti-thrombogenic endothelium lining the arterial lumen. The peptides P11-4, P11-8 and P11-12 were studied at different concentrations under physiological conditions using Fourier transform infrared spectroscopy and transmission electron microscopy as possible candidates for surface coatings. The peptides in their monomeric state were tested for anti-thrombogenic properties using a Chandler loop model. Self-assembly of peptides within acellular arteries was then assessed for the ability to form surface coatings by scanning electron microscopy, fluorescent microscopy and multiphoton laser scanning microscopy. P11 peptides were functionalised with bioactive cell attachment motifs (GRGDS and YIGSR) using copper catalysed azide-alkyne click chemistry. These motifs are found in extracellular matrix proteins and can be recognised by endothelial cell integrins. The effect of functionalisation on cell attachment of isolated ovine femoral endothelial cells onto acellular artery was assessed by live/dead® assay for 72 hours. The results showed that decellularisation of porcine external iliac arteries was reproducible with preserved extracellular matrix and DNA reduction of > 97 %. P11-4, P11-8 and P11-12 at 20 mg.mL-1, were shown to have high β-sheet proportions and the former two peptides were shown to form self-supporting gels almost instantaneously. P11-4 and P11-8 were shown to have anti-thrombogenic properties when present in blood potentially reducing thrombus formation. Moreover, the two peptides were shown to coat the extracellular matrix structures of the luminal surface of decellularised porcine external iliac arteries. In vitro, the bioactive peptides GRGDS-P11-4 and YIGSR-P11-4 were shown to enhance cell attachment and retention when compared to the corresponding scrambled control coatings, non-functionalised P11-4 coatings and uncoated acellular arteries. To conclude, the use of bioactive self-assembling peptides is a promising approach for improving the functionality of acellular arterial xenografts.
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Voorneveld, Jason Dirk. "High porosity electrospun scaffolds for small diameter vascular graft applications." Master's thesis, University of Cape Town, 2015. http://hdl.handle.net/11427/15762.
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Porosity, pore size and pore interconnectivity have been shown to be critical factors for cellular infiltration into vascular grafts. While electrospinning has been shown to produce many promising characteristics for the fabrication of vascular graft scaffolds, it has yet to create sufficient porosity for transmural endothelial in-growth. This study was aimed at using dual electrospinning with sacrificial fibre extraction to produce scaffolds with controllable porosity characteristics while maintaining sufficient structural strength to resist deformation during implantation. Scaffolds were subsequently covalently grafted with heparin, a known anti-coagulant with growth-factor binding properties.
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Lee, Carol Hsiu-Yueh. "Electrospun Polycaprolactone Scaffolds for Small-Diameter Tissue Engineered Blood Vessels." The Ohio State University, 2013. http://rave.ohiolink.edu/etdc/view?acc_num=osu1376924954.
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MacKellar, Iain Campbell. "The mechanical design aspects of a small diameter vascular prosthesis." Master's thesis, University of Cape Town, 1999. http://hdl.handle.net/11427/19572.
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Bibliography: pages 81-86.Failure of medium to small diameter vascular grafts is believed to be in part due to the compliance mismatch between the native artery and the implanted graft. Consequently, designers are examining the use of more compliant materials for their manufacture. Ether free polyurethanes are currently amongst the most popular materials for use in biological implants although these materials are inherently too stiff for use in vascular prostheses. These materials can be made more compliant by introducing porosity. Apart from creating a more compliant overall material, under optimal biological conditions, the porosity may lead to cell in growth through the thickness of the graft allowing an endothelial cell layer to form on the inner flow surface. Compliance and cell ingrowth are both important characteristics that determine the successful functioning of the graft. The current work is part of a collaborative venture with the Cardiovascular Research Unit (CVRU) at the University of Cape Town to design and develop a new polyurethane graft. Finite element models are used to facilitate stress analyses and to evaluate the long-term behaviour and compliance of various graft designs made from a bio-inert thermoplastic polyurethane. Material properties of the polyurethane are determined from uniaxial tension tests, simple-shear tests and viscoelastic shear tests. The constitutive equations for a compressible, large strain hyper elastic material model with viscoelasticity are implemented in the finite element code using material constants calculated from the test data. The behaviour of the finite element model is verified by using a single element test and comparing results to the material data. The finite element model is validated for use m more sophisticated problems by comparing axi-symmetric models with in vitro experiments. An artery/graft anastomosis is then analysed by modelling the artery as an incompressible hyperplastic material. Further more complex graft designs are analysed with internal growth channels and spiral reinforcing winds. Viscoelastic effects are also examined. The modelling method is discussed and important results are noted.
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Ryken, Marv, Rick Davis, and Scott R. Kujiraoka. "DESIGN OF A GPS/TELEMETRY ANTENNA FOR SMALL DIAMETER PROJECTILES." International Foundation for Telemetering, 2000. http://hdl.handle.net/10150/608282.
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International Telemetering Conference Proceedings / October 23-26, 2000 / Town & Country Hotel and Conference Center, San Diego, CaliforniaIn the past, airplanes, target drones, pods, and large missiles have been instrumented with telemetry, flight termination and beacon tracking antennas to assess performance. With the emerging use of the Global Positioning System (GPS) for tracking purposes, GPS is also included as part of the instrumentation package. This paper addresses the design of a conformal wraparound antenna system to cover the telemetry and GPS L1 frequencies for a small (2.75 inch) diameter airborne projectile. A filter is also integrated into the antenna system to isolate the transmitted telemetry signal from the received GPS signal. This integration is necessary due to the lack of space in the small diameter projectile. Performance characteristics of the prototype antenna system are also presented.
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Lusk, Kenneth P. "Flight Interruption System for a Small Diameter Missile with Telemeter." International Foundation for Telemetering, 1993. http://hdl.handle.net/10150/611831.
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International Telemetering Conference Proceedings / October 25-28, 1993 / Riviera Hotel and Convention Center, Las Vegas, NevadaA very restrictive down-range flight area for a small ground-to-air missile required the interruption of the flight after the missile had flown past a specialized target and telemetry data had been transmitted to a receiving station. Explosive bolts separated the missile into two sections and cables loosely attaching the two sections caused the system to tumble and therefore interrupt the flight. Because of the high dynamic forces exerted on the attaching cables, soft material "shock absorbers" were used to assure the integrity of the cables.
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Martin, Callizo Claudi. "Flow Boiling Heat Transfer in Single Vertical Channels of Small Diameter." Doctoral thesis, KTH, Tillämpad termodynamik och kylteknik, 2010. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-25797.
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Microchannel heat exchangers present many advantages, such as reduced size, high thermal efficiency and low fluid inventory; and are increasingly being used for heat transfer in a wide variety of applications including heat pumps, automotive air conditioners and for cooling of electronics.However, the fundamentals of fluid flow and heat transfer in microscalegeometries are not yet fully understood. The aim of this thesis is to contribute to a better understanding of the underlying physical phenomena in single-phase and specially flow boiling heat transfer of refrigerants in small channels. For this purpose, well-characterized heat transfer experiments have been performed in uniformly heated, single, circular, vertical channels ranging from 0.64 to 1.70 mm in diameter and using R-134a, R-22 and R-245fa as working fluids. Furthermore, flow visualization tests have been carried out to clarify the relation between the two-phase flow behavior and the boiling heat transfer characteristics. Single-phase flow experiments with subcooled liquid refrigerant have confirmed that conventional macroscale theory on single-phase flow and heat transfer is valid for circular channels as small as 640μm in diameter. Through high-speed flow boiling visualization of R-134a under non adiabatic conditions seven flow patterns have been observed: isolated bubbly flow, confined bubbly flow, slug flow, churn flow, slug-annular flow, annular flow, and mist flow. Two-phase flow pattern observations are presented in the form of flow pattern maps. Annular-type flow patterns are dominant for vapor qualities above 0.2. Onset of nucleate boiling and subcooled flow boiling heat transfer of R-134a has been investigated. The wall superheat needed to initiate boiling was found as large as 18 ºC. The experimental heat transfer coefficients have been compared to predictions from subcooled flow boiling correlationsav ailable in the literature showing poor agreement. Saturated flow boiling heat transfer experiments have been performed with the 640 μm diameter test section. The heat transfer coefficient has been found to increase with heat flux and system pressure and not to change with vapor quality or mass flux when the quality is less than ∼0.5. For vapor qualities above this value, the heat transfer coefficient decreases with vapor quality. This deterioration of the heat transfer coefficient is believed to be caused by the occurrence of intermittent dryout in this vapor quality range. The experimental database, consisting of 1027 data points, has been compared against predictions from correlations available in the literature. The best results are obtained with the correlations by Liu and Winterton (1991) and by Bertsch et al. (2009). However, better design tools to correctly predict the flow boiling heat transfer coefficient in small geometries need to be developed. Dryout incipience and critical heat flux (CHF) have been investigated in detail. CHF data is compared to existing macro and microscale correlations. The comparison shows best agreement with the classical Katto and Ohno (1984) correlation, developed for conventional large tubes.QC 20101101
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Corbeil, Antoine. "Study of Small Hydraulic Diameter Media for Improved Heat Exchanger Compactness." Thesis, Université d'Ottawa / University of Ottawa, 2011. http://hdl.handle.net/10393/19837.
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Solar radiation offers phenomenal potential for energy conversion with energy densities on the order of 1000W/m2 in locations with regularly clear skies. As always, the difficulty lies in finding a solar-electric conversion technology capable of producing electricity at a competitive cost. The SolarCAT (Solar Compressed Air Turbine) system produces electricity by releasing stored compressed air through a series of turbines with solar dish concentrators providing the required heat for efficient conversion to electricity. To minimize impact on capital cost, high recuperator effectiveness targets are sought but unlike typical fuel-fired micro-turbines, raising the recuperator effectiveness of the solar power system yields a benefit in overall system capital cost. Improving efficiency lowers the size and cost of the largest element of the system, namely the dish.
In this study potential techniques for achieving a highly compact heat-transfer media were reviewed. Folded fin, packed beds, micro-tubes, lattice frame structures, metal foams, woven textile, and micro-machining techniques were assessed. Textile structures were selected as an appropriate medium to replace the internal folded fin of the SolarCAT recuperator. The relatively long flow (>150mm) path through the proposed screen wafers requires a model for fully-developed forced convective flow between parallel plates. A mathematical model was developed by integrating the results from the work of several authors in the field of textiles and porous media. #100 mesh sintered screen wafers were brazed between two 0.25mm stainless steel sheets and destructively tested to assess their tensile strength. Although
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optimization of the braze parameters was not completed, it was found that many samples survived exposure to internal pressures in excess of 50MPa.
This study found that the use of sintered screen wafers to replace the internal folded fin of the SolarCAT recuperator would have advantages over the current design with respect to both overall recuperator effectiveness, size, and cost. Textile structures can be tailored to have wide range of fluid and heat-transfer properties depending on the application. The manufacturing process is relatively simple and could be cost-effective for high-volume production.
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Rininger, Zachary Scott. "The utilizaton of small diameter timbers in pultruded long strand composites." Online access for everyone, 2008. http://www.dissertations.wsu.edu/Thesis/Summer2008/Z_Rininger_072108.pdf.
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Huo, Xiaorong. "Experimental study of flow boiling heat transfer in small diameter tubes." Thesis, London South Bank University, 2005. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.435236.
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Ivanavicius, Stefan Paul. "Subtypes of small-diameter sensory neurons in the rat knee joint." Thesis, University of Bath, 2005. https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.425509.
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Chen, Lejun. "Flow patterns in upward two-phase flow in small diameter tubes." Thesis, Brunel University, 2006. http://bura.brunel.ac.uk/handle/2438/5104.
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Two-phase flow in small tubes and channels is becoming a common phenomenon in industrial processes. However, the study of two-phase flow regimes in small tubes is still at its infancy. The previous studies are reviewed and discussed in the literature section. The problems and inconsistencies encountered in the earlier studies are presented and discussed. The experimental facility is introduced in the chapters that follow. They include a section on the design of the experimental system and the test sections, the selection of the experimental parameters and the introduction of the purposely-developed programs to control the experiments and collect and process the data. The methodology of the calibration and the uncertainty analysis, the problems encountered and their solutions and the single-phase validation experiments are also described. In this project we studied the effect of tube diameter and fluid flow parameters on flow patterns in small tubes using R134a as the working fluid. The tested tube diameters were 1.10, 2.01, 2.88 and 4.26 mm; the fluid pressures were 6, 10 and 14 bar; the liquid and gas superficial velocities covered a range of 0.04-5.0 m/s and 0.01-10.0 m/s respectively. The observed flow patterns included bubbly, dispersed bubble, confined bubble, slug, chum, annular and mist flow. Twelve integrated flow maps are sketched in this report. The obtained results were compared with earlier experiments by other workers and with existing models, with obvious differences in the prediction of the transition boundaries. A set of new models and correlations were developed, based on the new data for boiling R134a presented in this thesis, to predict the effect of tube diameter and fluid properties on the transition boundaries. Some also agreed with the limited data available from earlier studies for adiabatic air-water flow in small to normal size tubes.
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Adom, Ebenezer. "Investigation of boiling heat transfer on small diameter tubes and tube bundles." Thesis, Heriot-Watt University, 2007. http://hdl.handle.net/10399/2067.
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Boiling heat transfer on the outside of small diameter tubes in the range of 1.8-3.0mm has been investigated. Pool boiling was investigated at nominal atmospheric pressure for each of the tubes iIi isolation. The experiment was varied by investigating the effect of bubbles from a second tube mounted below by varying the heat flux on the upper tube. The upper tube diameter was changed from 3.00 to 2.32 and 1.83mm and in each case the lower tube was 3.00mm. Experimental results showed that the upper tube heat transfer coefficient was enhanced due to the combined mechanism of translating bubbles and turbulent convection at low to moderate heat fluxes. A compact tube bundle made up of 30 stainless steel tubes of outer diameter 3nun, pitch diameter ratio 1.5 and heating length of 50nun was designed to. permit the measurement of flow boiling heat transfer coefficient from tubes within the bundle. The heat flux tested was in the range of 4-21 kW/m2 and mass flux of 5.6-32.8 kg/m2s using distilled water, R-l13 and Flutec PPI at nominal atmospheric pressure as the working fluids. Results obtained showed that the heat transfer coefficient was predominantly dependent on the heat flux as opposed to mass flux. Macro scale models were compared with the experimental results and none of these models predicted the experimental results well. The Confinement number (Co) developed for flow boiling inside micro channels was applied to compact tube bundles and it was shown that confinement is expected ~o be significant for Co>0.63. Photographic studies. also showed that the diameter of the bubbles that were generated within the,bundle were greater than the tube diameter. As such, the sliding bubbles mechanism played less significant role in contributing to the heat transfer coefficient. The recent three-state correlation developed by Thome et al for flow boiling .he.at transfer in micro .channels was modified to predict the experimental results obtained using a compact tube bundle and it has been shown that the thin film evaporation was the dominant mechanism compared to the nucleate boiling. The results from the twin tube and compact bundle arrangement showed two regions coexist at any point in time; that part of the tube covered with liquid subject to nucleate boiling and the other part completely enveloped with vapour. This latter part is designated by the introduction of a factor p and this has been demonstrated experimentally and theoretically corroborated by a model based on a liquid part (i-p) and vapour part p.
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Elsayed, Ahmed Mohamed. "Heat transfer in helically coiled small diameter tubes for miniature cooling systems." Thesis, University of Birmingham, 2011. http://etheses.bham.ac.uk//id/eprint/2907/.
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This thesis describes experimental and theoretical investigation on the use of small diameter helically coiled tubes for the evaporator of miniature refrigeration systems. A detailed review of past experimental and theoretical work on boiling heat transfer inside helically coiled tubes is presented. As most of past work was conducted on helical coils with tube diameters larger than 6 mm, a brief review of the flow boiling heat transfer process inside straight tubes with small diameters of less than 3 mm is also presented. An experimental facility was constructed and instrumented to investigate the flow boiling of refrigerant R134a in helically coiled tubes with diameters ranging from 2.8 mm to 1.1 mm and coil diameter ranging from 30 mm to 60 mm. The experimental results showed that decreasing the tube diameter increases the boiling heat transfer coefficient by up to 58% while decreasing the coil diameter increased the boiling heat transfer coefficients more significantly by up to 130% before dryout. Dimensional analysis using Pi theorem and Artificial Neural Network (ANN) techniques were used to develop correlations to predict the flow boiling heat transfer coefficients inside helically coiled tubes. The ANN method produced a better prediction of the experimental results with ±30%. The experimental facility was equipped with a reciprocating compressor and a manual expansion device and instrumented to assess the performance of miniature vapour compression refrigeration system. A mathematical model of this miniature system was developed, validated and then used to optimise the system performance in terms of the geometry of the helical coils used in the evaporator and condenser. It was shown that the smaller the coil diameter, the better the performance of cooling system. For the same evaporator length, the larger the tube diameter, the larger surface area and better COP. Smaller tube diameters showed better performance at lower area ratios. However, smaller tube diameters showed lower performance at high area ratios due to the large pressure drop caused by smaller tubes in case of using high area ratios. Finally, the addition of AL2O3 nanoparticles to pure water was investigated using computational fluid dynamics technique (CFD) in terms of heat transfer and pressure drop of single phase laminar and turbulent fluid flow in both straight and helically coiled tubes. The tested AL2O3 nanofluid in helical coils produced up to 350% increase in the heat transfer coefficient of the laminar flow compared to pure water in straight tubes for the same flow conditions. However, insignificant enhancement of the heat transfer was obtained in the turbulent flow regime. Also, the use of high AL2O3 nanofluid concentration of above 2% was found to produce significant pressure drop penalty factor of 5 times that of pure water in straight tubes.
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Malaise, Sébastien. "Small Diameter Vascular Substitues Based on Physical Chitosan Hydrogels : Proof of Concept." Thesis, Lyon 1, 2014. http://www.theses.fr/2014LYO10057.
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Le chitosane présente des propriétés biologiques (biocompatibilité, biorésorbabilité, bioactivité) idéalement adaptées à des applications en ingénierie tissulaire. Dans cette étude partenariale (Programme ANR TECSAN 2010 ChitoArt), nous avons travaillé à l'élaboration d'hydrogels physiques de chitosane à propriétés physico-chimiques et biologiques variées et contrôlées, sans utilisation d'agents de réticulation externes. Ces hydrogels sont envisagés sous forme de tube mono ou pluri-membranaires pour une utilisation en tant que substituts vasculaires de petit diamètre (<6mm). En effet, l'ingénierie vasculaire présente, encore de nos jours, de nombreuses limitations lorsqu'il est question de vaisseaux de petits calibres. Notre démarche consiste en la modulation des paramètres structuraux (degré d'acétylation, masse molaire) et environnementaux (concentration du bain de gélification, du collodion) intervenants dans le procédé d'élaboration des hydrogels pour atteindre les critères physiques, biologiques et mécaniques compatibles avec cette application. L'étude morphologique des hydrogels par Cryo-Microscopie Électronique à Balayage (Cryo-MEB), via une méthode de préparation originale a permis une meilleure compréhension de l'organisation micro-structurale et multi-échelle des hydrogels de chitosane. Cette approche fondamentale a été couplée à une évaluation in vivo des propriétés biologiques des hydrogels ainsi qu'a des caractérisations mécaniques des substituts vasculaires. En particulier, l'évaluation de la suturabilité de nos substituts a mené au développement d'une formulation donnant lieu à des hydrogels physiques de chitosane suturables ayant fait l'objet d'un dépôt de brevet (N° de dépôt FR1363099). Le contrôle et la modulation des paramètres d'élaboration des hydrogels ont permis l'obtention de substituts vasculaire cellularisables et respectant les exigences (suture, compliance, résistance à l'éclatement) concernant leur implantation in vivoChitosan presents biological properties (biocompatibility, bioresorbability, bioactivity) ideally suited for tissue engineering. In this partnership study (ANR TECSAN 2010 ChitoArt program), we worked at the elaboration of physical chitosan hydrogels presenting various and controlled physicochemical and biological properties, without any external crosslinkers. These hydrogels are envisioned under mono- or poly-membranous tubes for small diameter vascular substitutes (<6mm) purposes. Indeed, vascular engineering presents, even today, numerous limitations for small calibre vessels. Our strategy consists in the modulation of both structural (degree of acetylation, molar mass) and environmental (neutralization bath and collodion composition and concentration) parameters involved in hydrogels elaboration process in order to reach physical, biological and mechanical requirements suitable for this application. The study of hydrogels morphology by Cryo-Scanning Electron Microscopy (Cryo-SEM), using an original sample preparation method led to a better comprehension of chitosan hydrogels fine structure and multi-scale organization. This fundamental approach was conducted through the in vivo biological evaluation of hydrogels but also to mechanical characterizations of vascular substitutes. In particular, our substitutes were evaluated in term of suture retention resulting in the development of a formulation that led to suturable physical chitosan hydrogels, which were protected by a patent (Deposit number: FR1363099). Hydrogels elaboration parameters control and modulation have resulted in the development of colonisable vascular substitutes matching their in vivo implantation requirements (suture retention, compliance, burst pressure)
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Garcia, Almanza Cuautli Ignacio. "Development of a Multi-Body Autonomous Inspection Robot for Small Diameter Pipes." Thesis, Université d'Ottawa / University of Ottawa, 2020. http://hdl.handle.net/10393/40970.
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The most common way to transport oil and natural gas in Canada is by using pipes. In the last years, population growth has led to an increase in the pipeline network. This increase will generate new areas of research such as the detection of leakages or cracks and the maintenance of the pipeline system as a whole.
In this thesis, a novel hypermobile robot, capable of moving along pipes of different diameters, is proposed and developed. The robot is composed of three modules, two propulsive modules and one control module linked by passive joints. The propulsive module has eight actuators: four gearmotors to propel the robot along the pipe, and four servomotors to control the radial position of the robot in the pipe and to maintain the robot's balance. A Raspberry Pi is used to control the actuators, acquire sensor feedback, and receive commands from a remote wireless user-controlled GUI.
An existing dynamic controller is adapted to the robot's architecture. Simulations and experimental tests in open-loop and closed-loop modes are performed to evaluate the effectiveness of the robot's design and controller. The results show the efficiency of the mechanical and electronic components of the robot since it is capable of following the generated paths. The outcome of this thesis can be used in trajectory tracking controllers and for in-pipe robot design.
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Dudash, Lynn Ashley. "Cell Selective Endothelialization of Biomimetic Materials for Modifying Small Diameter Vascular Grafts." Case Western Reserve University School of Graduate Studies / OhioLINK, 2013. http://rave.ohiolink.edu/etdc/view?acc_num=case1373032790.
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Critchley, Katherine. "Process analysis software for draw bending of small diameter thin walled tubes." Thesis, Coventry University, 2002. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.393986.
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Lamonde, Jeff. "Development of a Multi-Body Autonomous Inspection Robot for Small Diameter Pipes." Thesis, Université d'Ottawa / University of Ottawa, 2017. http://hdl.handle.net/10393/36351.
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The pipeline network of North America is thousands of kilometer long and is ever increasing. To ensure the safety of every individual whose lives are affected by this network, the inspection of the pipelines are mandatory. With the steady progress and downsizing of robotic components, the wireless inspection of smaller pipelines is now a possibility and is the principal driver of this research. Mainly, the scope of this project is to explore the feasibility of the fabrication of a robot to inspect pipes of diameter of six to eight inches. Various design possibilities and the inherent problems of small confined environments inspections are investigated. The parameters for the fewest number of collisions for the design of a pipe robot is presented and various pipe scenarios are simulated. Finally, a prototype is fabricated and recommendations are suggested for future subsequent iterations of the robot.
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Ganin, A. A. "Length Dependence of Band Structure in Carbon Nanotubes of Ultra Small Diameter." Thesis, Sumy State University, 2013. http://essuir.sumdu.edu.ua/handle/123456789/35569.
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The paper presents results of a study of the band structure and related parameters and also the bond energy of single-walled carbon nanotubes carried out using semiempirical methods and ab initio density functional theory implemented in Gaussian 2003 framework. Much attention is paid to the dependency of the values mentioned on the length and on the chirality of the tubes. Both the infinite and the finite open-ended nanotubes are considered. It was found that the dependency of the band gap on the diameter has os-cillating character for infinite zigzag semiconducting tubes. It was also found that finite armchair nano-tubes have non-zero band gap which decreases showing oscillations with the length and decreases mono-tonically with the diameter.
When you are citing the document, use the following link http://essuir.sumdu.edu.ua/handle/123456789/35569
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Voth, Christopher Ray. "Lightweight sandwich panels using small-diameter timber wood-strands and recycled newsprint cores." Pullman, Wash. : Washington State University, 2009. http://www.dissertations.wsu.edu/Thesis/Fall2009/c_voth_120609.pdf.
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Thesis (M.S. in civil engineering)--Washington State University, December 2009.Title from PDF title page (viewed on Jan. 26, 2010). "Department of Civil and Environmental Engineering." Includes bibliographical references.
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Wang, Shuwu. "Biomimetic fluorocarbon surfactant polymers designed for use on small diameter ePTFE vascular graft." online version, 2004. http://rave.ohiolink.edu/etdc/view?acc%5Fnum=case1089933591.
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Parikh, Vijay. "Design and development of novel 'off the shelf' small diameter helical electrospun graft." Thesis, University of Bolton, 2016. http://ubir.bolton.ac.uk/930/.
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There is an acute clinical need for small-calibre (<6 mm) vascular grafts for surgery, but unlike their large counterparts they still fail in long-term clinical application. The failures of small diameter grafts are primarily due to the early formation of thrombosis and intimal hyperplasia. Dynamics of blood flow leading to wall shear rate and blood flow pattern and their effect on the endothelial cell proliferation along with other anomalies, have been identified as one of the major deciding factors for the efficiency of grafts. Research has showed that intimal hyperplasia and associated complications which leads to the failure of graft develop preferentially in regions where there is disturbed blood flow haemodynamics which leads to uneven shear stress and turbulence in the flow, followed by flow stagnancy in the periphery of the graft. On the basis of these findings and the established advantages of swirling physiological blood flow, a new graft design having a swirling flow inducer on the inner surface of the graft throughout the axis has been proposed. Initially, different swirling profiles have been analysed using final elemental analysis and compared with conventional or plain grafts. The numerical analysis has revealed that the proposed design could indeed produce the swirling blood flow with much better haemodynamics. These analyses have shown that compared to plain graft, in swirling graft, blood flow velocity near the vessel walls significantly enhanced with uniform distribution of shear stress and thus could theoretically enhance performance of the grafts by providing a "wash away" effect and prevent the plaque formation. Electrospinning has been used to fabricate the proposed design and prototype samples have been produced using polyvinyl alcohol (PVA) and gelatine. After cross linking, prototype grafts have been tested as per standard protocols and various tests such as; uniaxial tensile tests, bursting strength tests and suture retention test were carried out and results were evaluated and compared with the conventional grafts. Human coronary artery, endothelial cells (HCAEC) and human cardiac myocytes (HCM) were seeded on the helical and plain grafts using surface seeding technique. At various time intervals cell proliferation, viability and morphology were observed in the presence of static and circulating media and results were compared with their conventional counterpart kept under the same conditions. Results obtained showed considerable amount of difference in cell spreading and cell viability in the helical graft as compared to the conventional graft which provided the advantage edge. Also, in the case of helical graft more uniformly in arranged HCAEC were observed with elongated morphology. Pressure myography studies were performed on both grafts and after endothelization, the helical graft proved to be more reliable and capable of withstanding the pressure as compared to conventional counterparts. It is therefore suggested, that the electrospun helical graft designed and fabricated in this work may be an attractive candidate for use as a potential small diameter vascular graft for implantation. This is based on its ability to better regulate haemodynamics of blood flow and support endothelization, albeit in vivo studies are required to fully substantiate the in vitro results.
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Guilliatt, Robert Stephen. "Self-assembling functionalised peptides into decellularised materials for application in small diameter vascular grafts." Thesis, University of Leeds, 2013. http://etheses.whiterose.ac.uk/5566/.
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There is a clear clinical need for small diameter blood vessel grafts. Previous studies have shown that decellularised porcine arteries have potential for future development and clinical translation. However, in order to overcome the problems of thrombogenesis and encourage endothelialisation in small diameter applications, it will be necessary to devise innovative approaches. In this study it was hypothesised that a bioactive peptide could be self-assembled within the decellularised tissue to overcome the problems of thrombogenesis and to aid and enhance re-endothelialisation. A method for self-assembling the tape forming peptide, P11-4 within decellularised tissues was developed. The study then went on to explore the P11 series of peptides as materials for tissue engineering by examining biocompatibility and haemocompatibility and demonstrated the use of self-assembled peptide coatings to prevent thrombus formation and enhance re-endothelialisation. The self-assembly of peptide P11-4 within decellularised porcine internal carotid artery was assessed using a range of microscopic and spectroscopic techniques. Fluorescent microscopy was used to show the penetration of the peptide throughout the decellularised conduit. Self-assembly of the peptide was assessed by FTIR spectroscopy. Using CLSM and MPLSM it was shown that the peptide self-assembled around the extracellular matrix of the acellular tissue. Fluorescent microscopy was used in conjunction with a specially designed flow cell to show that the peptide coating remained in the decellularised vessel for over 14 days under model flow conditions. The biocompatibility and haemocompatibility of a library of 43 peptides was assessed to identify ideal candidate peptides for use and to develop design characteristics for the application of self-assembling peptides in biomedical settings. Testing was carried out using cytotoxicity testing, the Chandler loop thrombosis model, a haemolysis assay and a complement inhibition assay. The results showed that large poly-cationic peptides were non-bio or haemo compatible, large neutral peptides enhanced thrombosis formation and that poly-anionic peptides with hydrophobic cores inhibited the complement system. Peptide coatings of P11-4, P11-8 and P11-12 were shown to decrease, and in the case of P11-12 prevent, thrombus formation; showing potential for application in small diameter acellular blood vessels. Peptide P11-4, functionalised with cyclic RGD, was shown to enhance the attachment and retention of ovine endothelial cells on the decellularised vessel, demonstrating the potential of functionalised peptide to enhance re-endothelialisation. In conclusion, this study has demonstrated the potential of self assembling peptide technology for improving the function of acellular porcine arteries in vitro.
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Bukowski, Edward F., and T. Gordon Brown. "Design and Implementation of an Inertial Measurement Unit (IMU) for Small Diameter Ballistic Applications." International Foundation for Telemetering, 2009. http://hdl.handle.net/10150/606005.
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ITC/USA 2009 Conference Proceedings / The Forty-Fifth Annual International Telemetering Conference and Technical Exhibition / October 26-29, 2009 / Riviera Hotel & Convention Center, Las Vegas, NevadaThe US Army Research Laboratory currently uses a variety of ballistic diagnostic systems for gathering aerodynamic information pertaining to gun launched munitions. Sensors are a vital component of each of these diagnostic systems. Since multiple sensors are commonly used, they are often configured into a sensor suite or inertial measurement unit (IMU). In order to gather information on smaller diameter projectiles, a small diameter IMU was designed using commercial-off-the-shelf (COTS) sensors and components. This IMU was first designed with a 21.6mm diameter and then later reintegrated into a 17.5mm diameter unit. The IMU provides up to ten sensor data channels which can be used to make in-flight projectile motion measurements. These measurements are then used in the determination of the projectile's aerodynamics. It has been successfully flight tested on a variety of projectiles. It has been used in conjunction with an on-board recorder (OBR) to take measurements on 40mm and 25mm projectiles. It has also been used in a telemetry based system on-board a flare stabilized 25mm projectile. This paper covers the design of the IMU and gives examples of various sensor data.
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Docé, Tiago Soares. "Avaliação de derivações em sistemas de tubulações sujeitas à vibração." reponame:Biblioteca Digital de Teses e Dissertações da UFRGS, 2015. http://hdl.handle.net/10183/133117.
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Essa dissertação aborda o estudo teórico, experimental e computacional de algumas configurações usuais para derivações de pequeno diâmetro, interligadas a uma tubulação principal, sujeitas à vibração. O estudo de vibração, induzida por diversos fatores, foi a base teórica utilizada para a previsão de esforços máximos admissíveis e garantia da confiabilidade das tubulações. A confecção dos corpos-de-prova buscou a reprodução de condições típicas de uso em instalações de petróleo e gás, visando uma comparação de desempenho para as diferentes condições de montagem. Também foi realizada uma etapa de avaliação computacional, usando o programa Triflex para verificação da frequência natural e rigidez do conjunto montado. As análises de deslocamentos e esforços através dos dados obtidos pela instrumentação das peças soldadas e resultados do programa ANSYS apresentaram resultados importantes, enfatizando a resistência mecânica de determinadas configurações de menor comprimento ou com reforço vinculado à tubulação principal, as quais podem ser utilizadas em projetos de tubulações, melhorando a confiabilidade das instalações.This dissertation adresses the theoretical, experimental and computational study of some usual settings for small diameter pipe, connected to a main pipe, subject to vibration. The study of vibration induced by several factors was the theoretical basis used for predicting maximum permissible efforts and ensuring the reliability of pipes. The creation of the specimens sought to reproduce typical use conditions in the oil and gas factories aimed at comparative performance for different installation conditions. It was also performed a computational evaluation stage using software Triflex to check the natural frequency and rigidity of the mounted assembly. The displacement analysis and effort for parts by informations obtained with instrumentation of welded pipes and results of ANSYS software presented important results, emphasizing the mechanical strength of certain settings with smaller length or with reinforcement linked to a main pipe which can be used in pipe projects, improving the reliability of the facilities.
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Kelly, Brian P., Sean D. Hayes, and Brett Stevens. "Cost effective analysis comparing the small diameter bomb and the joint standoff weapon (A+ Variant)." Monterey, California. Naval Postgraduate School, 2004. http://hdl.handle.net/10945/9906.
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MBA Professional ReportApproved for public release; distribution in unlimited.
This MBA project investigated and analyzed the cost effectiveness of implementing the Joint Standoff Weapon A+ (JSOW A+) variant versus the Small Diameter Bomb (SDB). The primary goal was to compare the "cost per kill" for each weapon system in its intended operational environment against an existing target set. The secondary goal was to determine most cost effective optimum mix of weapons that would destroy the given target set. The optimum mix was determined using either the SDB or the JSOW A+ in combination with the current family of JSOW weapons, and was calculated based upon each weapons' cost-effectiveness. A computer model generated the cost-effectiveness of each weapon system by dividing weapon cost by weapon effectiveness. During the process of answering our research questions we discovered different scenarios identifying JSOW A+ as comparatively more, and in several scenarios comparatively less cost-effective than the SDB. The scenarios and results are subject to the assumptions and limitations defined within this report. This project explores the different scenarios to provide the acquisition program manager with the relevant data to make informed decisions concerning the direction of their program.
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Heilshorn, Sarah Christine Tirrell David A. "Design and characterization of artificial extracellular matrix proteins for use as small-diameter vascular grafts /." Diss., Pasadena, Calif. : California Institute of Technology, 2004. http://resolver.caltech.edu/CaltechETD:etd-05242004-103633.
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Perkins, Brian Russell. "A Business Model for a Red Oak Small Diameter Timber Processing Facility in Southwest Virginia." Thesis, Virginia Tech, 2006. http://hdl.handle.net/10919/36333.
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The conversion of red oak small diameter timber (SDT) into solid wood products was investigated. The objectives of this research were to
1) determine the yield of lumber, pallet and container parts, and residues from SDT and the market potential for these products;
2) determine the economic feasibility of a SDT sawmill and pallet part mill located in Southwest Virginia;
3) develop a business plan for a SDT sawmill and pallet part mill located in Southwest Virginia.
The methods for this research consisted of resource, yield and economic analyses, and the development of a business model. The resource analysis indicated an ample supply of red oak SDT available in Southwest Virginia. The yield analysis used red oak SDT logs, which were manufactured into lumber, container parts and wood residues. The yield of 3" wide container parts from cants varied from 63% to 66%. The 1" nominal lumber produced was mainly 2A and 3A, 74%, and 24% was 1 common. The economic analysis utilized break even, net present value and internal rate of return analyses to determine the economic feasibility of utilizing red oak SDT.
The results of the study indicated that the sawmill-only processing level scenario is not economically feasible given the specified conditions and assumptions. However, the results showed that the sawmill and pallet part mill, actual yield scenario at $35/ton delivered log cost is economically feasible. The hypothetical business model for Southwest Custom Hardwoods was economically feasible. The final net present value was calculated to be over $750,000 and the final internal rate of return was 11%. Future yield studies should weigh logs so that the yield of residues and solid wood products can be directly compared. Future research into the utilization of hardwood SDT should include yield studies of other species and other product mixes.Master of Science
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Chaloupka, K. "Development of a small diameter conduit for upper lacrimal system disorders using a novel nanocomposite polymer." Thesis, University College London (University of London), 2011. http://discovery.ucl.ac.uk/1317732/.
Full textAbstract:
Obstruction of the lacrimal drainage system can lead to constant tearing (watery eyes, “epiphora”) resulting in irritation of the eye region, disturbed vision and therefore serious reduction of life comfort. Watery eyes are a frequently encountered symptom in daily ophthalmological practice more seen in the elderly patient, but also in young people and children. Current treatment options of epiphora due to lacrimal duct obstructions in the upper part of the drainage system are very limited. In 1963 Lester Jones developed a bypass system formed by a rigid glass tube guiding the tear straight into the nasal cavity. This tube causes frequent complications due to dislocation, blockage and irritation of the eye and nose. Other options include reopening of the drainage system with drills or lasers and placement of stents. None of these options are optimal. The aim of this research was the development of a new lacrimal duct device using a novel nanocomposite polymer based on polyhedral oligomeric silsesquioxanes (POSS) nanoparticles and poly (carbonate-urea)urethane (PCU). POSS self assembles on surface during extrusion and creates a nanotopography surface. The small diameter conduit was manufactured for replacement of a non-functional or missing upper lacrimal duct (canaliculus). Several methodologies including ultrasound atomisation, electrodynamic spraying, dip coating and coagulation techniques were used to construct a lacrimal drainage conduit (LDC) using POSS-PCU, with a diameter of 800 μm representing the size of a canaliculus. In a further development of the research we manufactured a POSS-PCU nanocomposite modified with silver nanoparticles (nanosilver) enhancing the antimicrobial and antiscarring properties of the conduit. Extensive material testing was performed to optimise the synthetic LDC. Finally, the LDC made of POSS-PCU with nanosilver was implanted for the first time in human, in a 41-year old patient in a compassionate case with successful outcome.
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Cirineo, Tony, Rick Davis, Marvin Byrd, and Scott Kujiraoka. "Design and Development of a Thin Conformal C-Band Telemetry Antenna for a Small Diameter Missile." International Foundation for Telemetering, 2011. http://hdl.handle.net/10150/595618.
Full textAbstract:
ITC/USA 2011 Conference Proceedings / The Forty-Seventh Annual International Telemetering Conference and Technical Exhibition / October 24-27, 2011 / Bally's Las Vegas, Las Vegas, NevadaThis paper will present the preliminary design of a C-Band telemetry antenna mounted conformal to a small diameter missile. Various design studies and options will be explored leading to a preliminary design that best meets system requirements. Simulation results are presented for various options and the rationale for down selection to final configuration is discussed.