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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
271

Displacement i hälsenan under löpning med olika skor : Analys med hjälp av speckle tracking-algoritm / Displacement in Achilles Tendon During Running with Different Shoes : Analysis with Speckle Tracking Algorithm

Kaewkam, Natthaphong, Öberg, Joakim January 2023 (has links)
Hälsenan har en viktig roll för motoriken av underbenet samt rörelse vid gång och löpning. I och med detta sker det en stor belastning på hälsenan vid gång och löpning vilket kan leda till bristningar och skador på senan. Dessa bristningar kan ske när hälsenan deformeras i samband med fysisk aktivitet. Deformation av hälsenan är differensen mellan relativ displacement i senan och är ett viktigt koncept inom förståelsen om hälseneskadors etiologi. Syftet med detta examensarbete var att öka kunskapen om displacement i hälsenan och hur det skiljer sig vid habituell löpning med olika löparskor inklusive barfotalöpning. Vidare felsöktes en speckle tracking-algoritm som lägger grund för analysen av displacement i hälsenan. Arbetet är en utökning på ett pågående forskningssamarbete mellan KTH, GIH och KI. Det första steget i arbetet var att MATLAB-programmet för speckle tracking-algoritmen felsöktes och korrigerades. Detta gjordes genom att ändra initiala startvärden i algoritmen såsom centralfrekvensen och värdet för hastigheten av displacement i hälsenan. Efter att hastigheten valts till 2 cm/s fungerade algoritmen felfritt. Nästa steg var att exekvera programmet på den ultraljudsdata för hälsenan som tidigare samlats in från forskningssamarbetet. Algoritmen kördes för tre studiepersoner för habituell löpstil med tre olika löparskor samt barfota. Detta resulterade i att medelvärdeskurvor för ytlig och djup displacement i hälsenan kunde plottas där dess minimum- och maximumvärden kunde jämföras. Efter att differensen för minimum- och maximumvärdet för ytlig och djup displacement hade jämförts mellan samtliga löparskor samt barfota, kunde följande konstateras. Löpning med traditionella skor medförde högst djup displacement följt av skor med kolfibersula, minimalistiska skor och barfotalöpning. Den sko som medförde högst ytlig displacement var skor med kolfibersula följt av traditionella skor, minimalistiska skor samt löpning barfota. Jämförelsen har ej baserats på någon statistisk grund då endast tre studiepersoner analyserades. Detta medför en viss osäkerhet gällande vilken skotyp som medför högst respektive lägst displacement. Bortsätt från denna osäkerhet kan det konstateras att resultat från tidigare studier tyder på liknande insikter. / The Achilles tendon plays a crucial role in the motor function of the lower leg, as well as in the motion involved in walking and running. As a result, the Achilles tendon undergoes significant stress during walking and running, which can lead to tears and injuries to the tendon. These tears can occur when the Achilles tendon is deformed associated with physical activity. The deformation of the Achilles tendon is the difference between the relative displacement in the tendon and is an important concept in understanding the etiology of Achilles tendon injuries. The purpose of this thesis is to increase knowledge about the displacement in the Achilles tendon and how it differs during habitual running with different running shoes, including barefoot running. Furthermore, a speckle tracking algorithm that forms the basis for analyzing the displacement in the Achilles tendon is debugged. The work is an extension of an ongoing research collaboration between KTH, GIH, and KI. The first step in the work was to debug and correct the MATLAB program for the speckle tracking algorithm. This was done by changing initial starting values in the algorithm such as the central frequency and the value for the speed of displacement in the Achilles tendon. After choosing a speed of 2 cm/s, the algorithm worked flawlessly. The next step was to execute the program on the ultrasound data for the Achilles tendon previously collected from the research collaboration. The algorithm was run for test subjects 17, 18, and 21 for habitual running style with three different running shoes and barefoot. This resulted in mean value curves for superficial and deep displacement in the Achilles tendon being plotted, with their minimum and maximum values being compared. After comparing the difference between the minimum and maximum values of superficial and deep displacement across all running shoes as well as barefoot, the following observations were made. Running with traditional shoes caused the highest deep displacement, followed by shoes with carbon fiber soles, minimalist shoes, and barefoot running. The shoe that caused the highest superficial displacement was shoes with carbon fiber soles, followed by traditional shoes, minimalist shoes, and running barefoot. The comparison was not based on any statistical basis since only three test subjects were analyzed. This implies some uncertainty as to which type of shoe causes the highest and lowest displacement. Aside from this uncertainty, it can be noted that the results from previous studies have findings that suggest similar insights.
272

Examining the dynamic cascading of international norms through cluster genealogies. 1998 UN Guiding Principles on Internal Displacement and Other Cases

Sumita, Benita January 2016 (has links)
In 1998 the UN Guiding Principles on Internal Displacement were developed following years of crises faced by the millions of people experiencing forced displacement, especially those internally displaced. These Principles were widely considered to be precedent setting, both historically and normatively. However, the examination of the construction of the international norms that underpin the Principles indicates that there are important epistemological weaknesses in widely used constructivist frameworks that understand normative shifts in international relations. They are critiqued as being impedingly linear, temporally compressed and analytically obstructive in its agent-centric view of norm cascading. This research aims to address some of these gaps with an enhanced life-cycle model using cluster genealogies and the processes of replication and particularization. The reformulated framework is tested for robustness and feasibility using two preliminary cases – UNSC Resolution 1325 and the Chemical Weapons Convention. It is then used to conduct an in-depth original analysis of the development of the 1998 UN Guiding Principles. The findings in the case of the Guiding Principles show, for example, that though the acceptance of the IDP definition was a big leap, the replication and particularization of human rights limits the humanitarian scope of the Guiding Principles, and also brings into question existing humanitarian protection of IDPs under the Geneva Conventions. Meanwhile, rooting them in ‘sovereignty as responsibility’ has not shifted the community of states’ intersubjective take on sovereignty, but it has added to the existing normative tension – individual vs. state – that underpins the very understanding of sovereignty.
273

Distal Radius Fractures : aspects on radiological and clinical outcome and evaluation of a new classification system

Wadsten, Mats January 2016 (has links)
Distal radius fracture (DRF) is the most common fracture encountered in clinical practice. Every year, more than 20000 people in Sweden suffer from this injury. It has been shown that there is a correlation between malalignment and function following distal radial fractures and malunion may cause persistent pain and disability. A problem has been in making a correct initial assessment of the fracture. Many fractures are unstable despite an acceptable position on the initial radiographic examination or following a successful closed fracture reduction. Numerous classification systems have been developed for evaluation of DRF in order to predict the outcome. However, the values of these are limited since they have not shown satisfactory reliability. Furthermore, the utility of these systems to predict radiographic or clinical outcome is not yet proven. These shortcomings may be one reason why optimal DRF management is still controversial. Requests for a new classification system of DRF, predictive of outcome and easy to use, have been made. Improvement in initial assessment of DRF will benefit a large group of patients, as well as the society, by reducing persistent symptoms and disability. Study I: In this study we evaluated the interobserver and intraobserver reliability of a new classification system (the Buttazzoni classification). Two hundred and thirty-two patients with acute DRF were blindly evaluated using the new classification by three orthopaedic surgeons twice with a 1-year interval. The new classification showed fair to substantial interobserver and intraobserver reliability, i.e., results comparable with other commonly used classification systems. Study II: This was a prospective multicenter study of fracture stability in 428 DRF. The study investigated whether cortical comminution and intra-articular involvement, as well as the new classification system, could predict displacement in DRF. Logistic regression analysis showed that initial position of the fracture and volar or dorsal comminution predicted later displacement, while intra-articular involvement did not. Volar comminution was the strongest predictor of displacement. The new classification system, which is the first to include volar comminution as a separate parameter, was highly predictive of fracture instability. Furthermore we found that it is quite common for non-operatively treated fractures to displace at a later stage than two weeks. Study IV: In study II it was found that late displacement of DRF, still in acceptable radiologic position after 10-14 days, occurred in approximately 1/3 of cases. Despite this, we have not been able to find any study focusing on evaluating the clinical outcome in patients with late displacement. Two hundred and nine unilateral DRF from study II were still in good position after 10-14 days and were included in the study. One hundred and seventy five patients had radiographs taken at a minimum of 3 months and a clinical examination 1 year after the fracture. Late displaced distal radius fractures had significantly higher loss of ROM and grip strength compared to fractures that didn’t displace. No significant differences were seen in subjective outcome. In conclusion, initial position of the fracture predicted later displacement and was the most important parameter in predicting clinical outcome. Comminution of the fracture also affected radiological stability and clinical outcome. Volar comminuted fractures are highly unstable and need surgical intervention if displacement is to be avoided. Intra-articular involvement affected clinical outcome. Late displacement is common in DRF and may result in loss of range of motion and grip strength. To detect late displacement, DRF should be followed for more than 2 weeks. The new classification system had a moderate reliability and reproducibility. The classification was found predictive of radiologic and objective clinical outcome. However, it was not predictive of subjective outcome. The classification system was also predictive of fractures at risk for late displacement.
274

Livelihoods under stress : household assets and responses to environmental change in the Mekong Delta, Vietnam

Chun, Jane M. January 2014 (has links)
This thesis is a response to broad stroked claims that climate change and sea-level rise will cause mass displacements in areas such as the Mekong Delta. Instead, I argue for a more nuanced approach to understanding vulnerability and household response measures in contexts of environmental stress, and highlight the importance of deciphering differentiations of vulnerability across households of varying characteristics. I propose that in this way, by empirically understanding differentiated household vulnerabilities and response measures to stress rather than focusing on one type of stressor (environmental change) and response (migration), we would be better positioned to holistically address the root causes of vulnerability. To this end, I take a micro household-level approach, using an asset vulnerability framework, to assess the role of various household assets in mediating vulnerability and resilience in the rural Mekong Delta context. As a result, we are able to understand the interactions of numerous elements, including the effects of environmental stress and mobility decision-making processes, within the context of household asset profiles, which are in turn shaped by the broader political ecology. The main findings of this study furthermore include the ‘counterintuitive’ role of environmental stress, where it is found to be one of many stressors, often paling in comparison to the pressure of others. In the process of analysing resettlement outcomes, we encounter the process of vulnerability shifts, whereby some vulnerabilities are alleviated while others are increased as a result of resettlement. Finally, in terms of the link between environmental change and migration, a direct relationship is found to be tenuous. Instead, the key drivers, deterrents, and facilitators of migration are identified, pointing to the significance of assets and their role in shaping mobility decisions and outcomes for households. This leads us to not only think about those who move, but also those who do not have the option to move as a result of their poor asset profiles.
275

Effects of air dissolution dynamics on the behaviour of positive-displacement vane pumps: a simulation approach

Furno, Francesca, Blind, Vincent 27 April 2016 (has links) (PDF)
The aim of this paper is to evaluate the effects of the dissolution time – time for the liquid to absorb the gas till the saturation state - on the behaviour of positivedisplacement vane pumps, in terms of pressure peaks within internal chambers and forces applied to the stator ring. The chamber pressurization depends on the volume variation and fluid Bulk modulus in the pre-compression phase during which the volume is trapped between the suction and the delivery port rims. If the dissolution time is short, then the entrained air is quickly absorbed and the fluid Bulk modulus sharply increases just before opening the connection to the outlet; as a consequence, pressure peaks may appear thus degrading the NVH characteristics of the pump. Moreover the pressure within internal chambers generate i) a torque demand to the driver (the combustion engine or an electrical motor) and ii) a total force applied to the stator ring. In case of fixed displacement designs, the resultant pressure force simply represents a load for support bearings; while in case of variable designs, it contributes to the displacement regulation. Simulation results show that the pump behaviour is very sensitive to the dissolution time when it is quite close to the duration of the trapped period.
276

Experimental loss analysis of displacement controlled pumps

Lux, Jan, Murrenhoff, Hubertus 28 April 2016 (has links) (PDF)
Current efficiency measurements of variable hydraulic axial piston pumps are performed with the displacement system locked at maximum volume, thus without the controller. Therefore, the controller’s effect on the efficiency is not quantified at state of the art measurements. Former research on control systems mainly focused on the dynamic behaviour. This paper aims to quantify the losses in the displacement and control system and to research the dependencies of those. Therefore, a test rig is built up at IFAS to measure the control power of displacement controlled pumps. Furthermore, a simulation tool is developed to increase the understanding of the loss mechanisms of the investigated control systems. In conclusion, the paper shows the potential of efficiency improvements for displacement controlled pumps.
277

A Flow Control System for a Novel Concept of Variable Delivery External Gear Pump

Vacca, Andrea, Devendran, Ram Sudarsan 02 May 2016 (has links) (PDF)
This paper describes a novel concept for a low cost variable delivery external gear pump (VD-EGP). The proposed VD-EGP is based on the realization of a variable timing for the connections of the internal displacement chambers with the inlet and outlet ports. With respect to a standard EGP, an additional element (slider) is used along with asymmetric gears to realize the variable timing principle. Previously performed tests confirmed the validity of the concept, for a design capable of varing the flow in the 65%-100% range. Although the VD-EGP concept is suitable for various flow control system typologies (manual, electro-actuated, hydraulically flow- or pressure- compensated), this paper particularly details the design and the test results for a prototype that includes both a manual flow control system and a pressure compensator. Flow vs pressure and volumetric efficiency curves are discussed along with transient (outlet flow fluctuation) features of the VD-EGP.
278

Two supramolecular methods for detecting a cancer metabolite with cucurbituril

Li, Wei 03 May 2016 (has links)
The enzyme spermidine/spermine N1-acetyltransferase (SSAT) is a candidate biomarker for various cancers as its activity in cancerous tissues is significantly increased. An artificial molecule, amantadine, is exclusively acetylated by SSAT to acetylamantadine (AcAm), levels of which in urine can serve as a proxy biomarker for malignancy. Current method of AcAm detection is laborious, time-consuming, and lacks the possibility of transforming to a point-of-care device. In this thesis, two different approaches were applied to detect AcAm in deionized water and in human urine using optical methods. The first one was fluorescence-based indicator displacement assay using cucurbit[7]uril as the receptor molecule. The second was programmed gold nanoparticle disaggregation with cucurbit[7]uril as a molecular linker. / Graduate
279

Exploring displacement as a theoretical paradigm for understanding John Joubert's opera Silas Marner

Vos, Stephanie 12 1900 (has links)
Thesis (MMus (Music))--University of Stellenbosch, 2009. / ENGLISH ABSTRACT: In a world of increased mobility, a growing number of people find themselves in places other than those that they originate from. While a strong case has been made in various disciplines for the experiences of alienation and disruption emanating from the politically tinctured notion of exile, this thesis argues that these experiences affect all émigrés alike, be it the consequence of forced or voluntary migration. It is this study’s aim to nuance the understanding of displacement and explore the ways in which the exile discourse informs a general, less extreme discourse of voluntary displacement with specific reference to the composer John Joubert and his opera Silas Marner. In the first chapter, displacement is theorized as a doubleness or ambivalence that is important in understanding creative work done by those who have been displaced and that is informed, in the South African composer’s case, by the relationship between the centre of ‘the’ art music tradition in Europe and Britain and its ‘peripheral’ practice in South Africa. The second chapter argues the ways that notions of nationality still inform thinking about composers and their aesthetic in a time that nationality is no longer a monolithic, stable denominator. This is done with specific reference to the composer John Joubert. In the third and fourth chapters, the focus narrows to Joubert’s opera Silas Marner (op. 31), and explores displacement as a theoretical paradigm for reading and studying of the opera. The third chapter discusses the choice of subject matter of the opera and the significance of Eliot’s novel as basis for an operatic text. Finally, the fourth chapter provides a brief analysis of the opera, its conception and reception history as well as a critical discussion of the ways in which notions of displacement is present in this work. / AFRIKAANSE OPSOMMING: In ‘n wêreld wat meer toeganklik as ooit tevore is, bevind mense toenemend hulself in plekke elders as waar hulle vandaan kom. Terwyl die konsep van ballingskap, met sy politiese konnotasies, al deur verskeie dissiplines bestudeer en geteoretiseer is, argumenteer hierdie tesis dat die gevoel van vervreemding en ontwrigting wat daaruit spruit deur alle emigrante beleef word, synde die gevolg van willekeurige of onwillekeurige emigrasie. Hierdie studie stel homself ten doel om die begrip van ontheemding te nuanseer en die verskeie maniere waarop die ballingskapdiskoers tersaaklik is vir ontheemding, te belig. Dit sal gedoen word met spesifieke verwysing na die komponis John Joubert en sy opera, Silas Marner (op. 31). In die eerste hoofstuk word ontheemding geteoretiseer as ‘n dubbelsinnigheid wat belangrik is in die verstaan van die ontheemde se kreatiewe werk. Die verhouding tussen die sentrum van ‘die’ kunsmusiektradisie in Europa en Brittanje en die ‘periferale’ beoefening daarvan in Suid- Afrika word as bydraend tot hierdie dubbelsinnigheid gesien. Die tweede hoofstuk argumenteer dat nasionaliteit nie meer ‘n eenduidige, stabiele aspek in die beskouing van musiek en musiekestetika verskaf nie en bedink die maniere waarop nasionaliteit steeds betrekking op musiekstudie kan hê. Dit word met spesifieke verwysing na John Joubert gedoen. In die derde en vierde hoofstukke vernou die fokus na Joubert se opera Silas Marner en word die wyses waarop ontheemding tot ‘n lesing van die opera kan bydra verken. Die derde hoofstuk behandel die keuse van onderwerp vir die opera en die belang van Eliot se roman as operateks. Die vierde hoofstuk bespreek die ontstaans- en resepsiegeskiedenis van die opera, analiseer die opera kortliks en verskaf ‘n kritiese bespreking van die wyses waarop nosies van ontheemding in die opera teenwoordig is.
280

Stability analysis of a single three dimensional rock block: effect of dilatancy and high-velocity water jet impact

Asadollahi, Pooyan 27 May 2010 (has links)
In simulation of closely- or separately-joined rock masses, stability of rock blocks is of primary concern. However, there seems to be no approach that can handle general modes of simultaneous sliding and truly large rotation under general forces, including non-conservative forces such as water forces. General causes of failure for rock blocks, such as limit points, bifurcation points, and dynamic instability (divergence and flutter), have never been addressed. This research implements a formulation, called BS3D(an incremental-iterative algorithm introduced by Tonon), for analyzing general failure modes of rock blocks under conservative and non-conservative forces. Among the constitutive models for rock fractures developed over the years, Barton's empirical model has been widely used because it is easy to apply and includes several important factors associated with fracture characteristics. Although Barton's failure criterion predicts peak shear strength of rock fractures with acceptable precision, it has some weaknesses in estimating the peak shear displacement, post-peak shear strength, dilation, and surface degradation in unloading and reloading. In this dissertation, modifications are made to Barton's original model in order to address these weaknesses. The modified Barton’s model is validated by a series of direct shear tests on rock fractures and implemented in BS3D to consider the dilatant behavior of fractures. The mechanical behavior of a rock block formed in the roof of a tunnel is governed by its geometry, the mechanical characteristics and the deformability of the fractures forming the block, the deformability of the block and that of the surrounding rock mass, and the stresses within the rock. BS3D, after verification and validation, is used to investigate the effect of dilatancy on stability of rock blocks formed in the roof of a circular tunnel. High-velocity plunging jets, issuing from hydraulic artificial or natural structures, can result in scouring of the rock riverbed or the dam toe foundation. Assessment of the extent of scour is necessary to ensure the safety of the dam and to guarantee the stability of its abutments. BS3D is used to investigate effect of high-velocity jet impact on stability of rock blocks in plunge pools. / text

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