Introduction: Implicit within spinal manipulative therapy is the assumption that treatment loads are effectively transcribed to actuate consistent mechanisms for expected clinical results. There is conflicting evidence between the mechanistic understandings and the physiologic responses from experimental evidence. Greater clarity on how loads are transferred through tissues to the target sites would be useful in enhancing utilization and efficacy of spinal manipulative procedures. Purpose: Directly monitor displacement of tissue in strata at sequential depths between the load application site and target articulation in the thoracic spine. Tissue displacement served as a surrogate for evidence of load transmission. Methods: Ultrasound elastography techniques monitored displacement in sequential strata while electromyographic signals, force, kinematic motions were monitored synchronously. Volunteers were placed prone on a treatment table, while a typical spinal manipulative pre-load maneuver was applied in the thoracic spine. Results: When applying a therapeutic load to the skin the results demonstrate with increasing depth of tissue there is a sequentially decreasing rank order in the mean cumulative displacement with each layer being significantly greater than the deeper adjacent layer. Superficial loose connective tissue layer (0.34 mm ± 0.15) vs. intermediate muscle layer (0.28 mm ± 0.11), p=0.004. Intermediate muscle layer (0.28 mm ± 0.11) vs. deep muscle layer (0.16 mm ± 0.6), p<0.0001. Filtered myoelectric signals were linearly correlated with tissue strata cumulative displacements, but the relationship was not strong (-0.23 < r < 0.46). Conversely, Pearson correlation analysis revealed strong and relatively stable correlations (0.74 < r < 0.90) for the association between displacement at the load application site and tissue layers. Conclusion: The sequential tissue motion demonstrates that some degree of load transfer through layers occurs. Both direct and indirect stimulation of tissues across both depth and breadth is feasible, to an extent consistent with the stimulation of mechanoreceptors. / Thesis / Master of Science (MSc)

Osseointegrated transfemoral implants have been introduced as an alternative to conventional, socket-based prostheses for above knee amputees. This method is showing great promise; however, the frequency of device failure is of concern. As a means to understand some of these failures, this study investigates the mechanical behaviour of three osseointegrated transfemoral implant systems; an in-house prototype design and two assemblies comprised of implant-grade parts provided by Integrum AB, Sweden. A series of mechanical tests were administered to evaluate the effects of tightening specifications and connection geometry on the material response, and mechanical behaviour of the assemblies. The tests included torque-elongation measurements, torque to failure tests, and strain analyses during loading. This research was carried out in an attempt to better understand the behaviour of components under loading, in order to optimize the assembly specifications and improve the useful life of the system. The results obtained confirm that the Integrum assemblies exhibit improved performance when tightened to a level beyond the current specified tightening torque of 12 Nm. Increased tightening torque provides an improved connection between components, leading to increased torque retention, decreased peak tensile strain values and a more gradual, primarily compressive distribution of strains throughout the assembly. / Thesis (Master, Mechanical and Materials Engineering) -- Queen's University, 2009-09-29 12:14:18.438

No description available.

A recently proposed defense for the anonymity network Tor uses preload lists of domains to determine what should be cached in the Domain Name System (DNS) caches of Tor relays. The defense protects against attacks that infer what is cached in Tor relays. By having domains continuously cached (preloaded), the cache will become independent of which websites have been visited. The current preload lists contain useless domains and have room for improvement. The objective of this project is to answer the question of "How can we generate better preload lists?" and to provide improved methods for generating preload lists, with the ultimate goal of generating better preload lists that the Tor Project can benefit from.  We further developed existing tools to use web crawling to find more useful domains, as well as implementing filtering to remove useless domains from the preload lists. The results of this project showed promising results, as the useless domains decreased by an average of around 57% and more useful domains were found. / Ett nyligen föreslaget försvar för anonymitetsnätverket Tor använder preload listor av domäner för att avgöra vad som ska cachelagras i domännamnssystemets (DNS) cacher för Tor reläer. Försvaret skyddar mot attacker som avgör vad som cachelagras i Tor relärer. Genom att ha domäner kontinuerligt cachade (förladdade), blir cachen oberoende av vilka websidor som har besökts. De nuvarande preload listorna innehåller värdelösa domäner och har utrymme för förbättring. Syftet med detta projekt är att svara på frågan "Hur kan vi generera bättre preload listor?" och att bidra med förbättrade metoder för att generera preload listor, med det ultimata målet att generera bättre preload listor som Torprojektet kan dra nytta av. Vi vidareutvecklade befintliga verktyg till att använda webbkrypning för att hitta mer användbara domäner, samt implementerade filtrering av värdelösa domäner från preload listorna. Detta projekt visade lovande resultat, då de värdelösa domänerna minskade med i genomsnitt ungefär 57% och mer användbara domäner hittades.

Double-nut anchor bolt systems are used in the erection of traffic signal poles, high-mast luminaries, and other highway appurtenances. An absence of a tightening standard for such systems decreases the confidence in their performance under fatigue loading. Past research has shown that a tightening standard should include the development of preload in the anchor bolt sufficient to provide adequate resistance to fatigue failure. Preload should be measured by a turn-of-the-nut method. Laboratory progressive tightening tests were performed in order to monitor the stress ranges occurring in the bolt at various locations of interest at various degrees of turn-of-the-nut tightness. Tests were performed on six diameters of anchor bolt ranging from 1 to 2-1/4 inches in diameter and two different categories of thread pitch: UNC and 8UN. Plots of stress range versus degree of tightness were developed for each test and evaluated to find the minimum degree of turn-of-the-nut at which stress range inside the nuts dropped below that outside the nuts. This shift was considered to be the principle theoretical indication of adequate performance. A fatigue test which saw failure outside the double-nut connection was set down as the practical indicator of adequate fatigue performance. The 2 inch 8UN bolt was chosen as the critical specimen due to its overall low generation of preload during tightening tests. Theoretical testing showed that 1/24 turn-of-the-nut would guarantee sufficient fatigue performance. Two practical fatigue tests of the bolt at that tightness saw one positive and one negative failure. After actual lab tests, finite element modeling was used to investigate the behavior of the bolt. It was found that performance did not see improvement until 1/12 turn-of-the-nut. After all results were considered, a standard of 1/6 turn-of-the-nut or refusal of tightening by specified methods was recommended, provided a minimum of 1/12 turn-of-the-nut was achieved. This value allows for ease of measurement, sufficient tightness, degree of safety, and has been shown in past testing not to cause failure through over-tightening. However, tightening to only 1/12 turn-of-the-nut still provided adequate performance.

Scania CV AB is one of the world’s leading companies within heavy vehicles. The company have a broad selection of trucks, which all are equipped with gas, or fuel tanks, depending on the fuel type of the truck, The trucks also contain air tanks that are used for braking and air suspension. The tanks are assembled with straps, where the rubber spacers constitutes a protective layer between the tank and the strap, to protect the tank from wear. When installing different types of tanks there is a need for elements in the joint that increases the friction, compensates for manufacturing defects, prevents wear and permits electrical insulation. This has traditionally been done with rubber spacers. However, the rubber spacers increase the uncertainty of the actual preload of the joint, and movements in the joint usually make the spacers slip out of its position.  The purpose of the project is to generate knowledge on what characteristics and conditions that affects the performance of the friction joint, and to find a conceptual solution of the underlaying problem.        The following questions were created to be able to fulfill the purpose of the project: F1: Which underlying causes generate preload loss in the straps when assembling various tanks? F2: Which underlying causes makes rubber spacers tend to slip out of its position in various tank installations? F3: What operations need to be undertaken to prevent the preload loss in the straps and that the rubber spacers slip out of its position?  A case study and a literature review was conducted. The literature review was done to get an overall understanding of all of the different subjects that can be of relevance in this project. The data was collected from books, research papers and scientific articles. Data was also collected from interviews, technical reports, deviation reports, legal requirements, drawings, statistics from the field quality and observations in production.  The case study is based on a product development process where several different product development tools have been used. The case study also include material testing in terms of friction and settlement testing. The project resulted in a concept in the shape of a rubber spacer which is based on the existing solution that Scania is using today. The solution consists of four components: geometries that prevent the rubber from slipping away known as flanges and geometries in the shape of tips of a fir tree, rounded short sides and a dimpled underside. The size of the spacer will vary because of the different types of tank and strap sizes. The project also resulted in a design guideline, that will provide guidelines and guidance for further work and future design. / Scania CV AB är ett av de världsledande företagen inom tunga fordon. Deras utbud av lastbilar är brett, och lastbilarna är utrustade med gas-, eller bränsletankar, beroende på fordonets drivmedel. Lastbilarna är även utrustade med trycktankar som används vid inbromsning och luftfjädring. Tankarna är monterade med spännband, där gummimellanlägg utgör ett skydd mellan tank och spännband för att skydda tanken mot nötning. Vid installation av olika lastbilstankar finns behov av element i förbandet som ökar friktionen, kompenserar formfel, förhindrar nötning, och medger elektrisk isolation. Detta har traditionellt gjorts genom att använda gummimellanlägg i förbandet. Gummimellanlägg ökar dock osäkerheten i den faktiska förspänningen av förbandet, samt rörelser i konstruktionen ofta får mellanlägget att vandra ur position.  Syftet med projektet är att skapa förståelse för vilka egenskaper och förutsättningar som påverkar prestandan av ett friktionsbetingat förband, samt att hitta konceptuell lösning på grundproblematiken. För att kunna fullgöra syftet har följande frågeställningar utformats:F1: Vilka orsaker ligger till grund för att förspänningen i spännbanden släpper vid montering av diverse fordonstankar?F2: Vilka orsaker ligger till grund för att gummimellanlägg tenderar att vandra ur position i olika tankinstallationer?F3: Vilka åtgärder kan vidtas för att motverka att förspänningen i spännbanden släpper och att gummimellanläggen vandrar ur position? I arbetet har en fallstudie och en litteraturstudie genomförts. Litteraturstudien utfördes för att skapa övergripande förståelse i ämnen som kan vara relevanta för arbetet. Den insamlade informationen härrör från böcker, forskningsavhandlingar och vetenskapliga artiklar. Data har även samlats in i form av intervjuer, tekniska rapporter, felrapporter, lagkrav, ritningar, statistik i fältkvaliteten, och observationer i produktionen. Fallstudien baseras på en produktutvecklingsprocess där flera produktutvecklingsverktyg har använts. I fallstudien ingår även materialprov i form av friktion och sättning. Arbetet resulterade i ett koncept i form av ett gummimellanlägg och baseras på Scanias befintliga lösning. Lösningen består av fyra komponenter: geometrilåsning i form av flänsar och så kallade grantoppar, rundade kortsidor och gropig undersida. Storleken kan däremot variera på grund av spännbandens och tankarnas breda storleksspann.  Arbetet har även resulterat i en design-guideline, som ska ge riktlinjer och vägledning för fortsatt arbete och framtida konstruktion.

Scania CV AB is one of the world’s leading companies within heavy vehicles. The company have a broad selection of trucks, which all are equipped with gas, or fuel tanks, depending on the fuel type of the truck, The trucks also contain air tanks that are used for braking and air suspension. The tanks are assembled with straps, where the rubber spacers constitutes a protective layer between the tank and the strap, to protect the tank from wear. When installing different types of tanks there is a need for elements in the joint that increases the friction, compensates for manufacturing defects, prevents wear and permits electrical insulation. This has traditionally been done with rubber spacers. However, the rubber spacers increase the uncertainty of the actual preload of the joint, and movements in the joint usually make the spacers slip out of its position.  The purpose of the project is to generate knowledge on what characteristics and conditions that affects the performance of the friction joint, and to find a conceptual solution of the underlaying problem.        The following questions were created to be able to fulfill the purpose of the project: F1: Which underlying causes generate preload loss in the straps when assembling various tanks? F2: Which underlying causes makes rubber spacers tend to slip out of its position in various tank installations?F3: What operations need to be undertaken to prevent the preload loss in the straps and that the rubber spacers slip out of its position?  A case study and a literature review was conducted. The literature review was done to get an overall understanding of all of the different subjects that can be of relevance in this project. The data was collected from books, research papers and scientific articles. Data was also collected from interviews, technical reports, deviation reports, legal requirements, drawings, statistics from the field quality and observations in production.  The case study is based on a product development process where several different product development tools have been used. The case study also include material testing in terms of friction and settlement testing. The project resulted in a concept in the shape of a rubber spacer which is based on the existing solution that Scania is using today. The solution consists of four components: geometries that prevent the rubber from slipping away known as flanges and geometries in the shape of tips of a fir tree, rounded short sides and a dimpled underside. The size of the spacer will vary because of the different types of tank and strap sizes.  The project also resulted in a design guideline, that will provide guidelines and guidance for further work and future design. / Scania CV AB är ett av de världsledande företagen inom tunga fordon. Deras utbud av lastbilar är brett, och lastbilarna är utrustade med gas-, eller bränsletankar, beroende på fordonets drivmedel. Lastbilarna är även utrustade med trycktankar som används vid inbromsning och luftfjädring. Tankarna är monterade med spännband, där gummimellanlägg utgör ett skydd mellan tank och spännband för att skydda tanken mot nötning. Vid installation av olika lastbilstankar finns behov av element i förbandet som ökar friktionen, kompenserar formfel, förhindrar nötning, och medger elektrisk isolation. Detta har traditionellt gjorts genom att använda gummimellanlägg i förbandet. Gummimellanlägg ökar dock osäkerheten i den faktiska förspänningen av förbandet, samt rörelser i konstruktionen ofta får mellanlägget att vandra ur position.  Syftet med projektet är att skapa förståelse för vilka egenskaper och förutsättningar som påverkar prestandan av ett friktionsbetingat förband, samt att hitta konceptuell lösning på grundproblematiken. För att kunna fullgöra syftet har följande frågeställningar utformats:F1: Vilka orsaker ligger till grund för att förspänningen i spännbanden släpper vid montering av diverse fordonstankar?F2: Vilka orsaker ligger till grund för att gummimellanlägg tenderar att vandra ur position i olika tankinstallationer?F3: Vilka åtgärder kan vidtas för att motverka att förspänningen i spännbanden släpper och att gummimellanläggen vandrar ur position? I arbetet har en fallstudie och en litteraturstudie genomförts. Litteraturstudien utfördes för att skapa övergripande förståelse i ämnen som kan vara relevanta för arbetet. Den insamlade informationen härrör från böcker, forskningsavhandlingar och vetenskapliga artiklar. Data har även samlats in i form av intervjuer, tekniska rapporter, felrapporter, lagkrav, ritningar, statistik i fältkvaliteten, och observationer i produktionen. Fallstudien baseras på en produktutvecklingsprocess där flera produktutvecklingsverktyg har använts. I fallstudien ingår även materialprov i form av friktion och sättning. Arbetet resulterade i ett koncept i form av ett gummimellanlägg och baseras på Scanias befintliga lösning. Lösningen består av fyra komponenter: geometrilåsning i form av flänsar och så kallade grantoppar, rundade kortsidor och gropig undersida. Storleken kan däremot variera på grund av spännbandens och tankarnas breda storleksspann.  Arbetet har även resulterat i en design-guideline, som ska ge riktlinjer och vägledning för fortsatt arbete och framtida konstruktion.

A prova de carga com cristaloides é uma das intervenções mais comumente realizadas diante da hipotenção trans-anestésica, contudo, nem todo animal que apresenta hipotensão é responsivo a fluidoterapia. Por esta razão, na ultima década, vários índices que avaliam a responsividade a fluido foram desenvolvidos com o intuito de otimizar o emprego da fluidoterapia no paciente hemodinamicamente instável. . O objetivo desse trabalho foi avaliar três diferentes índices de responsividade, quais sejam: a variação da integral velocidade-tempo (&Delta;IVT), variação da velocidade de pico do fluxo aórtico (&Delta;VFAO) e variação da pressão de pulso (VPP) no que tange a sua capacidade diagnóstica. Para tanto, foram utilizados 40 cães submetidos a anestesia inalatória associada a anestesia epidural. Em caso de detecção de pressão arterial média &lt; 65 mmHg, foi realizado uma prova de carga com cristalóde de 15 ml/kg durante 15 minutos. Volume sistólico (VS) obtido por meio da ecocardiografia transesofágica foi utilizado para definir a responsividade a fluido, sendo que os cães responsivos foram aqueles em que um aumentou no VS igual ou superior a 15% foi observado após o desafio com o cristalóide. Os dados foram avaliados pela análise da curva ROC para comparação dos testes diagnósticos, assim como a análise da curva cinzenta e também pela probabilidade pré e pós-teste. Trinta cães (75%) foram responsivos a fluidoterapia e 10 (25%) não eram responsivos. Tanto a &Delta;VFAO quanto a &Delta;IVT apresentaram boa capacidade discriminativa pela análise da Área sob a curva (0.89 e 0.93), assim como a VPP (0.88). Além disso, a análise da área cinzenta e da probabilidade pós-teste sugeriram uma melhor capacidade em diagnosticar os animais responsivos a fluido do que não-responsivos. Os valores de corte que distinguem responsivos a fluidoterapia de não-responsivos foram semelhantes aos observados na literatura. Sobe ventilação controlada e após a anestesia epidural, os índices ecocardiográficos de responsividade a fluido apresentaram boa capacidade discriminativa. / Intravenous fluid resuscitation is the first therapeutic choice used against arterial hypotension, however, not every animal with arterial hypotension is responsive to fluids. In the past decade, many indices of fluid responsiveness were introduced and plenty of studies covering many scenarios on the surgery context have been published. Therefore, the aim of this study was to evaluate the diagnostic accuracy of velocity-time integral variation (&Delta;TI), peak aortic velocity variation (&Delta;Vpeak) and pulse pressure variation (PPV). Forty dogs were included in this study. Whenever a mean arterial pressure &lt; 65 mmHg, a 15 ml/kg fluid challenge with crystalloids over 15 minutes was administered. Responders to fluids were defined by means of transesophageal echocardigraphy if an increase equal to or greater than 15% in stroke volume was observed after the fluid challenge. For the statistical evaluation, ROC curve analysis, gray zone approach, and pre-test, post-test probability were used to estimate the diagnostic capability of each index. Thirty (75%) dogs were responders and 10 (25%) were non-responders. Both velocity-time integral variation (&Delta;VTI) and aortic blood velocity variation (&Delta;Vpeak) showed a good diagnostic capability according to the Area under curve analysis (0.89 e 0.93), as well as PPV (0.88). Moreover, the gray zone approach and the post-test probability suggests a greater ability to detect fluid responders. The optimum cutoff value to discriminate responders from non-responders for all dynamics indices were similar to that observed in the literature. After the epidural anesthesia and under mechanical ventilation, all dynamic índices showed good diagnostic ability in predicting fluid responsiveness.

Developments in micro and nano technology have great potential in many applications. Two applications that will be addressed in this work are self assembly of microdevices and Electrowetting in microfluidics. Capillary forces are the most critical factor in both of these techniques and need proper characterization. This thesis describes a detailed study of these forces and explains how they were utilized as an effective source of drive in high end applications. Self assembly is a promising alternative to conventional pick and place robotic assembly of micro components. Its benefits include parallel integration of parts with low equipment costs. Various approaches to self assembly have been demonstrated, yet demanding applications like assembly of micro-optical devices require increased positioning accuracy. This thesis proposes a new method for design of self assembly bonds that addresses this need. Current methods have zero force at the desired assembly position and low stiffness. The proposed method uses a substrate assembly feature to provide a high accuracy alignment guide to the part. The capillary bond region of the part and substrate are then modified to create a non-zero positioning force to maintain the part in the desired assembly position. Capillary force models show that this force aligns the part to the substrate assembly feature and reduces the sensitivity of part position to process variation. Thus, the new configuration analyzed proves substantial improvement in positioning accuracy of capillary self assembly. Guidelines are proposed for the design of an effective assembly bond using this new approach. Electrowetting is another application that has been successfully demonstrated as a means of drop manipulations in digital micro-fluidic devices. These demonstrations show that electrowetting actuation holds great promise, but there are also reports of erratic behavior and system degradation. While a method for electrowetting force measurement to track the degradation of the electrowetting response was demonstrated, this thesis analyzes some adverse effects in the electrowetting response due to variations during measurement of electrowetting forces, specially the variation of volume, the tilt in the part considered for measurements, and defective layer response.

This thesis presents methods to statistically quantify data from fastener vibration life tests. Data from fastener vibration life tests with secondary locking features of threaded inserts is used. Threaded inserts in three different configurations are examined: no locking feature, prevailing torque locking feature, and adhesive locking feature. Useful composite plots were developed by extracting minimum preloads versus cycles from test data. Minimum preloads were extracted due to the overlapping of varying test data and because the minimum preload is of most interest in such tests. In addition to composite plots, descriptive statistics of the samples were determined including mean, median, quartiles, and extents. These descriptive statistics were plotted to illustrate variability within a sample as well as variability between samples. These plots also reveal that characteristics of loosening for a sample, such as preload loss and rates of preload loss, are preserved when summarizing such tests. Usually fastener vibration life tests are presented and compared with one test sample, which is why statistically quantifying them is needed and important. Methods to predict the sample population have been created as well. To predict populations, tests to determine the distribution of the sample, such as probability plots and probability plot correlation coefficient, have been conducted. Once samples were determined to be normal, confidence intervals were created for test samples, which provides a range of where the population mean should lie. It has been shown that characteristics of loosening are preserved in the confidence intervals. Populations of fastener vibration life tests have never before been presented or created. The evaluation of loosening has been conducted for fastener vibration life tests in the past with plots of one test sample; however, in this work statistically quantified results of multiple tests were used. This is important because evaluating loosening with more than one test sample can determine variation between tests. It has been found that secondary locking features do help reduce the loss of preload. The prevailing torque secondary locking feature is found to be more effective as preload is lost. The best secondary locking feature has been found to be the adhesive.