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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.
461

Anthropometric, Strength, and Power Determinants of Throwing Performance in Collegiate Throwers.

Swisher, Anna Meisinger 09 May 2009 (has links) (PDF)
The purpose of this study was to identify the anthropometric, strength, and power characteristics that best predict throwing performance. Seventeen male D-I throwers (age = 19.1 ± 1.2 y; body mass = 115.1 ± 15.3 kg; height = 1.85 ± 0.06 m) were assessed for maximum strength and power. A five variable linear regression (r = 0.94, r2 = 0.88, F(5,11) = 15.89, p < 0.001, SEE = 0.68) explained 88% of the variation in shot put (SP) performance. A five variable linear regression (r = 0.91, r2 = 0.83, F(5,11) = 10.509, p = 0.001, SEE = 1.18) explained 83% of the variation in weight throw (WT) performance. Both SP and WT correlated strongly with measures of explosive strength and power (r = 0.48-0.78). Best predictors of performance were static vertical jumps and 7.26 kilogram overhead shot throw; better throwers possess greater maximum strength and power.
462

Kompositören i rånarluva : Referenslåtens påverkan vid skapandet av cinematisk musik / The composer in a robber's hat : The inluence of reference songs in the creation of cinematic music

Nygren, Axel January 2023 (has links)
I detta arbete har jag skrivit musik utifrån referenslåtar med syftet att undersöka hur referenslåtarna påverkar min kreativa arbetsprocess samt det klingande resultatet. Jag har gjort detta inom en stil som jag kallar för cinematisk musik och jag har använt filmmusik som referenser. Min metod har gått ut på att först lyssna in mig på referenslåtarna samt analysera dem, för att sedan plocka ut olika element som jag använt som byggklossar för att skriva nytt och eget material. Arbetet resulterade i fyra låtar, samtliga med en demoproduktion.  Av denna undersökning så har jag kommit fram till att referenslåtar kommer med både för- och nackdelar. Den främsta fördelen har för mig varit att jag har kommit in i skapandeprocessen med många idéer och mycket motivation. Det gjorde det enkelt att komma igång med processen av min egna låtar samt att jag har kunnat undvika den överväldigande känslan av att öppna ett tomt projekt. Nackdelarna visade sig senare i processen då jag ofta har jämfört mina egna låtar med referenslåtarna vilket har lett till en del negativa tankegångar. Dessutom har mina egna låtar många likheter med referenslåtarna och jag upplever själv att jag inte alltid lyckat nå fram med mitt egna musikaliska uttryck. Bortsett från detta så har arbetet varit både roligt och lärorikt.
463

An experiment on the lateral steering behaviour of cyclists on narrow bidirectional cycle tracks

Theuwissen, Eline, Schepers, Paul, Daamen, Winnie, Hagenzieker, Marjan, Nabavi, Matin 02 January 2023 (has links)
Cycling contributes to public health because it requires physical effort [1] and offers economic and environmental advantages over motorized transport [2]. However, 41,000 cyclists die every year in traffic crashes, 3% of the total worldwide [3]. Most fatal bicycle crashes are collisions with motor vehicles. Severe injuries among cyclists, however, are mostly due to single bicycle crashes and their numbers are increasing [4, 5]. An international review showed that the share of hospitalised casualties due to single-bicycle crashes varied from 3% to 41 % of the total number of hospitalised casualties [ 6]. ... The aim of the present study is to investigate the relationship between cycle track width and lateral position. We conducted an experiment in which the cycle track width was manipulated to determine its effect on lateral position. The results have been compared with previous findings from literature. [From: Introduction]
464

The Difference in HR Response between Track and Treadmill Running at a Pre-determined, Self-selected Pace

Corey, Marisha 22 March 2005 (has links) (PDF)
The purpose of this study was to determine whether or not differences exist in heart rate (HR) between jogging on the track and jogging on the treadmill at the same speed. Twenty-four college-age (19-31 years old) male (n = 12) and female (n = 12) recreational runners volunteered to participate in this study. Each participant performed a maximal graded exercise test (GXT) and four exercise sessions. During the first exercise session, participants completed a 1-mile steady-state jog on either the track or treadmill at a self-selected submaximal pace that could be maintained for 30 minutes. The following three exercise sessions were completed at the same pace as the first exercise session. Two of the exercise sessions were performed on the treadmill and two were performed on an indoor track. The order of the four sessions were counterbalanced. Participants were randomly assigned to an order of sessions. Heart rate was recorded every minute and the participants were asked to give an RPE at the end of every session. Statistical analysis revealed no significant differences in pace (mph) between the trials within the two track or two treadmill trials (p = 0.5812), in the HR response. Therefore, gender and trials were excluded from the final model, and the final model included only the treatment effect (track, treadmill). There was a significant treatment effect (F 1,94 = 39.126, p < 0.0001) indicating that significant differences in the HR responses between track and treadmill jogging at the same pace. Jogging on the treadmill elicited an average HR of 5.16 bpm (S.E. = 0.82) less than that observed while jogging on an indoor track at the same pace. We conclude that jogging on the treadmill and track at the same, self-selected speed results in HR values that differ significantly by 5 bpm. Differences in air resistance, biomechanics, and muscle activity most likely contributed to the observed differences in HR. The results of this study are applicable to various individuals who often train or exercise on the treadmill or overground. Use of a HR monitor is recommended to determine personal responses to exercise on a treadmill and overground.
465

Detection Likelihood Maps for Wilderness Search and Rescue: Assisting Search by Utilizing Searcher GPS Track Logs

Roscheck, Michael Thomas 03 July 2012 (has links) (PDF)
Every year there are numerous cases of individuals becoming lost in remote wilderness environments. Principles of search theory have become a foundation for developing more efficient and successful search and rescue methods. Measurements can be taken that describe how easily a search object is to detect. These estimates allow the calculation of the probability of detection—the probability that an object would have been detected if in the area. This value only provides information about the search area as a whole; it does not provide details about which portions were searched more thoroughly than others. Ground searchers often carry portable GPS devices and their resulting GPS track logs have recently been used to fill in part of this knowledge gap. We created a system that provides a detection likelihood map that estimates the probability that each point in a search area was seen well enough to detect the search object if it was there. This map will be used to aid ground searchers as they search an assigned area, providing real time feedback of what has been "seen." The maps will also assist incident commanders as they assess previous searches and plan future ones by providing more detail than is available by viewing GPS track logs.
466

Conceptual Design of an UnloadingSystem for Continuous Tracks : How to increase the load capacity of tracks with the use ofhydraulic cylinders / Konceptkonstruktion av ett avlastningssystemför bandenheter

Torstensson, Jonas January 2017 (has links)
This report presents the result of a Master thesis course done at the Machine Design department at KTH. The thesis was written at the company Svea Teknik in collaboration with the tunnel boring machine manufacturer Atlas Copco. The high longitudinal force needed when the Remote Vein Miner is boring is achieved by the friction when clamping the machine between the tunnels ceiling and ground using hydraulic cylinders mounted on the top and bottom of the machine. A new generation of machines doesn’t allow for the bottom cylinders to be fitted on the machine. The pair of continuous tracks used to propel the machine must bear these loads but the tracks aren’t strong enough to alone support the weight of the boring machine. This creates the need for an unloading system which unloads the inner wheels of the track so they don’t fail. Concepts were generated using a morphological matrix with the load sharing unit broken down to sub functions with several solutions paired to each. The iterative process led to nine concepts, where two proved more promising than the others when they were subjected to a Pugh’s evaluation matrix. The two concepts were developed further where a feasibility analysis indicated that only one concept was feasible with the dimensions given in a CAD model together with the load provided by Atlas Copco. The remaining concept is based on hydraulic cylinders lifting the inner wheels of the track to unload them while the machine is boring. The machine is then resting on a skid mounted inside the track. A CAD model was made of the new concept and the new components strength was analyzed using FEM-models. / I denna uppsats presenteras resultatet av ett examensarbete för masterprogrammet Maskinkonstruktion på KTH. Arbetet utfördes på förtaget Svea Teknik tillsammans med tunnelborrmaskintillverkaren Atlas Copco. De stora longitudinella krafterna som krävs när tunnelborrmaskiner borrar erhålls med hjälp av hydraulcylindrar monterade både på ovan- och undersidan av maskinen som klämmer fast maskinen mellan tunnelns golv och tak. En ny generation maskiner från Atlas Copco tillåter inte hydraulcylindrar monterade framtill på undersidan av maskinen. Istället tar de båda bandenheterna som är avsedd att driva maskinen framåt upp dessa krafter. Bandenheterna är inte tillräckligt starka för dessa laster utan en avlastningslösning för hjulen inne i bandenheten behövs. Problemet delades upp i subfunktioner som sattes in i en morfologisk matris för att generera koncept. Den iterativa processen ledde till nio koncept där två av dem visades mest lovade efter en konceptutvärdering med hjälp av en Pugh’s matris. De båda koncepten arbetades vidare till en mer detaljerad nivå där en rimlighetsanalys visade att endast ett koncept var fysiskt möjligt att applicera med de givna begräsningarna som gavs av utrymmet i den givna CAD-modellen tillsammans med de givna lasterna. Det kvarstående konceptet baseras på hydrauliska kolvar som monteras på hjulen i bandenheten. Dessa förflyttar hjulen uppåt tills de inte är i kontakt med bandenhetens kedja längre. Kedjan vilar då på en stödstruktur som är stark nog för lasterna. En CAD-modell gjordes på konceptet och de nya komponenternas hållfasthet analyserades med hjälp av FEM-modeller.
467

Life Cycle Assessment development for electrified roads : Case study for Sweden

Nádasi, Réka January 2017 (has links)
The increasing role of sustainability will lead the mobility by road into a more efficient and interactive system between infrastructure, environment and vehicles. The expand of emobility based on Electric Vehicles has been restricted by numerous shortcomings such as their driving range, the battery size, the dependence on charging stations and the time required for its charging. One of the solutions to overcome these limitations is can be the construction of electrified roads. The study compares the most significant opportunities for eRoads as the solutions ofInductive Power Transfer (IPT), conductive track and pantograph in climate change aspect.This thesis is also intended to describe these systems, as they represent different ways for reach electrification of ordinary roads. IPT is a contactless solution which uses the well-known electromagnetic induction principle. Pantograph and conductive track are both conductive solutions. In the first case, it is an overhead solution and for the track, the energy is transferred to the vehicles from a continuous rail embedded in the pavement. The aim of the study is to develop an open and transparent Life Cycle Assessment (LCA)framework for electrified roads that could be used for decision support. The main objective is to build a cradle-to-grave LCA model in SimaPro for an electrified highway asphalt road in Sweden. / A fenntarthatóság, fenntartható fejlődés világszerte egyre fontosabb szerephez jut,elősegítve ezáltal azt, hogy hagyományos útburkolatok helyett hatékonyabb, interaktív rendszerek kerüljenek kiépítésre. Ezek az „okos” utak összekapcsolják az infrastruktúrát, akörnyezetet és az embert, mint járművezetőt. Jelenleg, a már hagyományosnak mondható e-közlekedésnek – mely az elektromos autók használatán alapul – számos hátrányafigyelhető meg. Többek között a korlátozott vezetési távolság és akkumulátor méret,valamint a töltési lehetőségektől és töltésidőtől való függés. Ezek leküzdésének egyik módja lehet a villamosított utak építése és elterjedése. A tanulmány célja egy nyílt, átlátható és könnyen kezelhető életciklus-elemzés (LCA) keretrendszer kiépítése a villamosított utak számára, mint döntéstámogató rendszer ajövőbeli beruházásokhoz. Ez egy svédországi villamosított autópálya, SimaPro programbanlétesített életciklus-elemzés modell építésével kerül bemutatásra. A dolgozat a három legjelentősebb típusú rendszereket hasonlítja össze a klímaváltozást befolyásoló hatások tekintetében. Ezek az indukció elvén alapuló IPT, a vezető pálya és a pantográf megoldások. A tanulmány szintén hivatott bemutatni a rendszereket, minthogyezek merőben különböző elveken alapuló megoldásokkal érik el a hagyományos utakvillamosítását. Míg elektro-mágneses töltés elvén alapuló rendszer a kontakt nélküli megoldások közé tartozik, addig a másik két rendszer álladó fizikai kapcsolatot igényel a jármű és a töltési rendszer elemei között.
468

Railway track dynamic modelling

Blanco, Blas January 2017 (has links)
The railway vehicles are an increasing mean of transportation due to, its reduced impact on environment and high level of comfort provided. These reasons have contributed to settle a positive perception of railway traffic into the European society. In this upward context, the railway industrial sector tackles some important challenges; maintaining low operational costs and controlling the nuisance by-products of trains operation, the most important being railway noise. Track dynamic plays a main role for both issues, since a significant part of the operational costs are associated with the track maintenance tasks and, the noise generated by the track can be dominant in many operational situations. This explains why prediction tools are highly valued by railway companies. The work presented in this licentiate thesis proposes methodologies for accurate and efficient modelling of railway track dynamics. Two core axes have led the development of this task, on one hand, the rail modelling and, on the other hand, the characterisation of the finite length nature of track supports. Firstly, concerning the rail modelling technique, it has evolved under two major premises. On one hand, regarding the frequency domain, it should describe high frequency behaviour of the rail. In order to accomplish with this first premise, a model based on Timoshenko beam theory is used, which can accurately account for the vertical rail behaviour up to 2500 Hz. On the other hand, with respect to the time domain, the response should be smooth and free of discontinuities. This last condition is fulfilled by implementation of the Timoshenko local deformation. Secondly, a model of support that considers its finite length nature is sought. For this purpose, a Timoshenko element over elastic foundation is formulated. Thus, the common model of support, which is based on a concentrated connection, is substituted by a distributed model of support. In this way, several enhancements are achieved; the temporal contact force response is smoothed and a more realistic shape is obtained, the amplitude of the displacement due to the parametric excitation is reduced and the magnitude associated to the ‘pin-pin’ frequency is not overestimated. / <p>QC 20170522</p>
469

Utvärdering av statiska frekvensomformare till spårledningar för Stockholm tunnelbana / Evaluation of static frequency converters for track circuits in Stockholm subway

Esmaeilie, Ali January 2019 (has links)
Tunnelbanan är ett mycket viktigt transportmedel i Stockholm som är igång större delen av dygnet. Tunnelbanans Röda och Blå linjer använder sig av ett äldre signalsystem från 60-talet. Det system som används för signaleringen av de två linjerna är av typen växelströmspårledning med kodning och använder reläställverk. Spårledningarna som detekterar positionen av olika tåg på spåret använder frekvensen 75 Hz. Vid konverteringen av frekvensen 50 Hz till 75 Hz, uppstår koldamm och värmeförluster till utrymmet från frekvensomformaren. Koldammet som avges i luften riskerar att påverka reläfunktionaliteten när det tränger in i relähöljet och sätter sig på ytan för reläkontakterna i utrymmet bredvid frekvensomformare. Trafikförvaltningen har planer på att upprusta Röda linjens signalsystem för att kunna använda dess signalsystem i ytterligare 25 år. Spårledningssystemet positionerar och ger hastighetsbesked till tågen. En litteraturstudie har genomförts kring uppbyggnad av spårledningssystemet och tidigare forskning har utförts kring frekvensomformare för att hitta en ny frekvensomformare som inte riskerar reläfunktionaliteten. Genom faktainsamling från Trafikförvaltningen har nya lämpliga frekvensomformare som kunde ersättas mot de befintliga undersökts. Statiska frekvensomformare har analyserats. Enligt kraven från Trafikförvaltningen identifierades fyra produkter från olika leverantörer. Ingen av de statiska frekvensomformare var direkt kompatibel med befintligt system med anledningen av att systemet är byggd för ett roterande frekvensomformare. ”HZ-50-1105” från GoHz denna modell finns i 1-fas in- respektive 1-fas utmatning. ”FR-D 700” från Mitsubishi och ”Micromaster 440” från Siemens som hade lika användnings funktion det gjorde att de var lik varandra. ”ACS-150” från ABB denna modell hade som max märkeffekt upp till 4 kVA, vilket passar bara för frekvensomformare med märkeffekt 2.5 kVA. De olika typerna av statiska frekvensomformare belastade nätet på ett asymmetriskt sätt. Därför var det viktigt att kunna fördela lasten så jämnt som möjligt på varje fas. Det var svårt att kunna rangordna de valda produkterna utan det bara visades vilka valmöjligheter som fanns vid utbytet av roterande frekvensomformare. Användningen av statiska frekvensomformare eliminera de risker som en roterande frekvensomformare orsakar. Statiska frekvensomvandlare generera olika frekvenser med större noggrannhet samt de har en kortare driftsättnings tid men belastar de nätet asymmetriskt jämfört med roterande frekvensomformare. / The subway is a very important means of transport in Stockholm and is in operation most of the day. The Red and Blue lines of the metro use an older signal system from the 60s. The system used for the signaling of the two lines is of the type AC power line with coding and uses relay switches. The track circuit that detects the position of different trains on the track use the frequency 75 Hz. When converting the frequency 50 Hz to 75 Hz, carbon dust and heat losses is released to the space from the frequency converter. The carbon dust emitted into the air risks affecting relay functionality as it enters the relay housing and settles on the surface of the relay contacts in the space next to the frequency converter. The Traffic Administration have plans to upgrade the Red Line's signaling system in order to use the existing signaling system for another 25 years. The track circuit system positions and gives speed messages to the trains. A literature study has been conducted on the construction of the track circuit system and previous research has been conducted on frequency inverters to safely find a new frequency inverter that does not risk relay functionality. Through fact-finding from the Traffic Administration, new suitable frequency converters that could be replaced with the existing ones were investigated in this research. Static frequency converters were chosen to be investigated. According to the requirements of the Traffic Administration, four products were identified from different suppliers. None of the static frequency converters was directly compatible with existing systems because the system was built for a rotary frequency converter. "HZ- 50-1105" from GoHz this model is available in 1-phase input and 1-phase output respectively. "FR-D 700" from Mitsubishi and "Micromaster 440" from Siemens which were equal in and out connection. "ACS-150" from ABB this model had a maximum rated power up to 4 kVA, which is only suitable for frequency inverters with a rated power of 2.5 kVA. The various types of static frequency inverters loaded the network in an asymmetrical way. Therefore, it was important to be able to distribute the load as evenly as possible on each phase. It was difficult to be able to rank the selected products without just showing the choices that existed when replacing rotary frequency converters. However, the use of static frequency inverters eliminates the risks of a rotating frequency converter. Static frequency converters can more accurately generate different frequencies and they have a shorter commissioning time; however, they load the network asymmetrically compared to rotating frequency converters.
470

MQL versus Dry Machining - a Comparative Analysis in a Turning Process using LCA / MQL eller torrskärning -­ en jämförande studie för en svarvningsprocess med hjälp av LCA

Shams, Shadi January 2018 (has links)
During the last decades the challenge of sustainability has become more urgent and environmental impacts of different processes in manufacturing industry have received more attention. Life cycle assessment (LCA) has become an important and useful tool to evaluate the environmental impact of products and processes. In this study the environmental impact of two cooling techniques in a turning process has been evaluated using LCA. Turning is used for shaping metal parts by removing material. The compared cooling techniques in this study are dry cutting and Minimum Quantity Lubrication (MQL). The inputs and output in each technique are considered in form of material flows and energy consumption as well as waste flows. The Ecoinvent database has been used in order to quantify, evaluate and compare the environmental impacts of the two cooling techniques. Environmental impact categories considered in this study are Carbon footprint (CO2 kg equivalent), Cumulative Energy Demand (CED), Total eco-cost in Euro and ReCiPe. ReCiPe is a method used to evaluate multiple environmental impact categories and it covers impact categories related to human health, ecotoxicity and material depletion. Calculations and analysis of the results show that MQL has significantly lower environmental impact compared to dry cutting whereas energy consumption is the main contributor in the considered environmental impact categories. / Under de senaste åren har hållbar utveckling blivit mer relevant och miljöpåverkan av olika tillverkningsprocesser i industrin har således fått mer uppmärksamhet. Livscykelanalys (LCA) har blivit ett viktigt och användbart verktyg för att analysera och utvärdera miljöpåverkan av produkter och processer. I det här examensarbetet har miljöpåverkan av två olika kylmetoder vid svarvning utvärderats med hjälp av livscykelanalys (LCA). Svarvning används för att forma metalldelar. De jämförda kylmetoderna är torrskärning (dry cutting) utan kylvätska och minimalsmörjning (Minimum Quantity Lubrication - MQL) där en liten mängd smörjmedel används. Tillfört material, energiförbrukning och avfall vid varje kylmetod har betraktats. Ecoinvent-databasen har använts för att kvantifiera, utvärdera och jämföra miljöpåverkan av de två kylmetoderna. Miljöpåverkanskategorierna som behandlas i denna studie är koldioxidavtryck (CO2 kg ekvivalent), kumulativt energibehov (CED), totala miljökostnader i Euro och ReCiPe. ReCiPe är en metod som används för att utvärdera flera olika miljöpåverkanskategorier inkluderande människors hälsa, miljögifter och förbrukning av naturresurser. Beräkningarna och analysresultaten visar att MQL har betydligt lägre miljöpåverkan än torrskärning och att energiförbrukningen är den mest avgörande faktorn.

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