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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.
21

Paletový dopravník / Pallet conveyor

Klembara, Lukáš January 2009 (has links)
This master’s thesis describes the structural design of pallet conveyor for the transport pallet unit between the ground floor and upper storey of warehouse buildings, according to given technical parameters. The work includes design and functional solution for driven roller track. It solves lifting of frame cage and roller track and the pallet unit, using traction gearless drive. There is used cable transfer 2:1. Frame cage is equipped with a mandatory safety gear. The design is verified strength calculations of the frame lift and frame cage. Part of the thesis is the drawing documentation.
22

Kan SUMO användas för simulering av 2+1-vägar?

Calais, Ella, Kristofersson, Filip January 2021 (has links)
Traffic simulation is a growing research field which enables study and evaluation of the dynamics of a traffic system with the help of today’s various traffic simulation models. Rural roads with separated oncoming lanes and alternating lanes for overtaking, so-called 2+1 roads, are becoming increasingly common in Sweden due to its positive safety effects. In Sweden, there is today only one traffic simulation model developed for simulation of these road types, RuTSim (Rural Traffic Simulator). RuTSim is a research tool which makes it difficult to apply for others than the developers. This study therefore investigated whether the more accessible open-source code traffic simulation model SUMO (Simulation of Urban MObility) developed for urban and motorway traffic can be modified for modeling of traffic operations on 2+1 roads. Simulations of a virtual 2+1 road section were examined qualitatively and quantitatively using various comparison metrics aimed at capturing the characteristic traffic operations and human driver behavior on 2+1 roads. The results were further compared with an identical road section simulated in RuTSim. By adjusting parameters in the SUMO model and using its source code in its original form, the results show that it is to some extent possible to reflect the traffic operations and human driver behavior on 2+1 road, while some important mechanisms cannot be fully captured. By further modifying the source code in such a way that the speed of overtaking vehicles is temporarily increased, some of these missing mechanisms are successfully captured. The conclusion is that SUMO to some extent can model 2+1 roads, but the simulation model still lacks some basic mechanisms for capturing some of the traffic operations. For future studies, it is recommended to focus on further developing the sub-models for the merging behavior at the end of the two-lane sections, which differs compared to merging at on-ramps or lane closures since merging on 2+1 roads are part of an overtaking process.
23

Förseningstimmar på mötesseparerade 2+1-vägar : Hur förseningskostnaden påverkas av ombyggnad till 2+2-väg i relation till investeringskostnaden / Delay hours on 2+1-separeted roads : How the cost of delay hours are affected by reconstructing to 2+2-roads in relation to the investment cost

Hamadi, Farah, Wallin, Viktor January 2019 (has links)
Från slutet av 1990-talet har en stor mängd av de icke-separerade 13 meter breda vägarna byggts om till mötesseparerade vägar, där trafiken i varje riktning separeras med en mittremsa. Mötesseparerade vägar har varit ett mycket lyckat projekt för trafiksäkerheten och bidragit med en stor minskning av svårt skadade och döda i trafiken. Det finns många mötesseparerade vägar i Sverige. Vid olyckor på 2+1-vägar blir det svårt för trafiken att vända på vägen vilket leder till stopp och gör det även svårt för Blåljusmyndigheten samt bärgningsbilar att ta sig fram. Dessa olyckor leder till förseningstimmar och i sin tur till samhällskostnader. Det här examensarbetet är skrivet för Trafikverket för att granska 2+1-vägar i Trafikverkets Region Öst. Rapporten tar fram och jämför minskning av förseningskostnader efter en ombyggnad från 2+1- till 2+2-väg, rapporten tar även fram och jämför förseningskostnaden med investeringskostnaden för ombyggnationen. Resultatet för den här studien har framförts genom litteraturstudier, analys av data från Trafikledningen, webbverktyg och genom användning av Microsoft Excel för kalkylering av förseningstimmar och -kostnader för utvalda vägar och sträckor. Resultatet från rapporten visar om det är värt att undersöka en 2+1-väg för ombyggnation från 2+1- till 2+2-väg ur förseningskostnadsperspektiv. Detta redovisas genom en generell jämförelse per mil 2+1-väg baserad på väg 50, 55 och 56 i Trafikverkets Region Öst. Rapporten innehåller även en analys över de fem mest drabbade olycksplatserna på E18:s 2+1 sträckor. Analysen av dessa visade att alla fem sträckor låg mellan Köping och Västerås i Västmanland. / From the late 1990s, a large part of the non-separated 13-meter-wide roads have been reconstructed into meeting separated roads, where traffic in each direction is separated by a middle strip. Meeting separated roads have been a very successful project for road safety and have contributed to a large reduction in severely injured and casualties in traffic. There are many meeting separated roads in Sweden. In the case of accidents on 2+1-roads, it becomes difficult for the traffic to turn around on the road, which leads to a stop and makes it difficult for the emergency services and tow trucks to reach the scene of the accident. These accidents lead to delay hours and, in turn, to community costs. This thesis is written for the Swedish Transport Administration to review 2+1 roads in the Swedish Transport Administration’s Region East. The report produces and compares the reduction of delay costs after rebuilding a road from 2+1- to 2+2-standard, the report also presents and compares the delay cost with the investment cost for the reconstruction. This study is based on literature studies, analysis of data from the “Traffic Management”, internet-based programs and through the use of Microsoft Excel for calculating delay hours and -costs for selected roads and routes. The result of the report shows whether it is worth investigating in a reconstruction from 2+1- to 2+2-road from delay cost perspective. This is presented through a general comparison per Scandinavian mile of 2+1-road based on roads 50, 55 and 56 in the Swedish Transport Administration’s Region East. The report also contains an analysis of the five most affected accident sites on the E18's 2+1-routes. The analysis of these accident sites showed that all five were between Köping and Västerås in Västmanland county.
24

Estudos sobre Teorias com Chern-Simons: Equivalência entre Modelos e Efeito Aharonov-Bohm Não-Abeliano / Studies on theories with Chern-Simons: equivalence between models and Aharonov-Bohm effect is not abelian.

Malacarne, Luís Carlos 02 March 1999 (has links)
O objetivo desta tese é estudar alguns modelos contendo o termo de Chern-Simons, cuja presença induz várias características tais como massa topológica e spin fracionário. Iniciamos tratando o problema da equivalência entre os modelos Auto-Dual minimamente acoplado com o campo de Dirac, e o modelo de Maxwell-Chern-Simons com um acoplamento magnético com férmions. Nós mostramos que os setores fermiônicos dos modelos somente são equivalentes se adicionarmos uma auto-interação tipo Thirring. Em seguida, analisamos o efeito Aharonov-Bohm não-Abeliano para partículas de spin 0 e ½. Partindo da teoria quântica de campos relativística no gauge de Coulomb e usando o procedimento do corte intermediário, para separar o momento de integração nas regiões de baixa e alta energia, nós obtemos o limite não relativístico dos modelos. Desta forma as correções radiativas, tais como polarização do vácuo e correção de vértice, são automaticamente incluídas. Finalizando estudamos algumas / The aim of this work is to study some models with Chern-Simons term~ which induces several properties such as l-opological mass and fractional spin. We start studying the exact equivalence between the Self-Dual model minimally coupled to a Dirac field and the Maxwell-Chern-Simons model witb non-minimal magnetic coupling to fermions. Weshow that the fermions sectors of the models are equivalent only if a Thirring like interaction is included. Next we analyze the non-Abelian Aharonov-Bohm scattering for 0 and 1/2 spin particles. Starting Crom the relatistic quantum field theory and using 8 Coulomb gauge rormalism the one loop renorrnalizalion is implemented. Trough the introduction of na intermediaf) cutoff, separating the regions of high and low integration momentum the nonrelativistic Umit is derived. In this approach CJuant.um field theory vacuum polarization and anomalous magnetic momentum are automatically incorporated. Va also study some properties of the chat\'ged one spin particles interacting wit.h Chern Simons field.
25

Estudos sobre Teorias com Chern-Simons: Equivalência entre Modelos e Efeito Aharonov-Bohm Não-Abeliano / Studies on theories with Chern-Simons: equivalence between models and Aharonov-Bohm effect is not abelian.

Luís Carlos Malacarne 02 March 1999 (has links)
O objetivo desta tese é estudar alguns modelos contendo o termo de Chern-Simons, cuja presença induz várias características tais como massa topológica e spin fracionário. Iniciamos tratando o problema da equivalência entre os modelos Auto-Dual minimamente acoplado com o campo de Dirac, e o modelo de Maxwell-Chern-Simons com um acoplamento magnético com férmions. Nós mostramos que os setores fermiônicos dos modelos somente são equivalentes se adicionarmos uma auto-interação tipo Thirring. Em seguida, analisamos o efeito Aharonov-Bohm não-Abeliano para partículas de spin 0 e ½. Partindo da teoria quântica de campos relativística no gauge de Coulomb e usando o procedimento do corte intermediário, para separar o momento de integração nas regiões de baixa e alta energia, nós obtemos o limite não relativístico dos modelos. Desta forma as correções radiativas, tais como polarização do vácuo e correção de vértice, são automaticamente incluídas. Finalizando estudamos algumas / The aim of this work is to study some models with Chern-Simons term~ which induces several properties such as l-opological mass and fractional spin. We start studying the exact equivalence between the Self-Dual model minimally coupled to a Dirac field and the Maxwell-Chern-Simons model witb non-minimal magnetic coupling to fermions. Weshow that the fermions sectors of the models are equivalent only if a Thirring like interaction is included. Next we analyze the non-Abelian Aharonov-Bohm scattering for 0 and 1/2 spin particles. Starting Crom the relatistic quantum field theory and using 8 Coulomb gauge rormalism the one loop renorrnalizalion is implemented. Trough the introduction of na intermediaf) cutoff, separating the regions of high and low integration momentum the nonrelativistic Umit is derived. In this approach CJuant.um field theory vacuum polarization and anomalous magnetic momentum are automatically incorporated. Va also study some properties of the chat\'ged one spin particles interacting wit.h Chern Simons field.
26

Teoria escalar-tensorial: Uma abordagem geométrica

Almeida, Tony Silva 29 July 2014 (has links)
Submitted by Vasti Diniz (vastijpa@hotmail.com) on 2017-09-13T14:39:21Z No. of bitstreams: 1 arquivototal.pdf: 851323 bytes, checksum: 599a5da8bbbe70ff2f4ba121890878e2 (MD5) / Made available in DSpace on 2017-09-13T14:39:21Z (GMT). No. of bitstreams: 1 arquivototal.pdf: 851323 bytes, checksum: 599a5da8bbbe70ff2f4ba121890878e2 (MD5) Previous issue date: 2014-07-29 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES / In this cool thesis, we consider an approach to Brans-Dicke theory of gravity in which the scalar eld has a geometrical nature. By postulating the Palatini variation, we nd out that the role played by the scalar eld consists in turning the space-time geometry into a Weyl integrable manifold. This procedure leads to a scalar-tensor theory that di ers from the original Brans-Dicke theory in many aspects and presents some new features. We also consider the Weyl integrable geometry to investigate gravity in (2+1)-dimensions. We show that, in addition to leading to a Newtonian limit, WIST in (2+1) dimensions presents some interesting properties that are not shared by Einstein theory, such as geodesic deviation between particles in a dust distribution. Finally, taking advantage of the duality between the geometrical scalar-tensor theory and general relativity coupled with a massless scalar eld we study naked singularities and wormholes. / Esta tese trata de tópicos relacionados às teorias escalares-tensoriais e a geometria de Weyl integrável. Nossa abordagem será no sentido de indicar a geometria de Weyl integr ável como sendo um ambiente natural para a introdução de teorias escalares-tensorias. Nossa discussão será em torno da teoria de Brans-Dicke, considerada o protótipo das teorias escalares tensoriais, no entanto a discussão é facilmente estendida para essas versões mais gerais. Fazemos isso em dois momentos. Primeiro, indicando, no âmbito da teoria de Brans-Dicke, que na estrutura geométrica e de campos adotadas pela teoria existe uma relação estreita com a geometria de Weyl, inclusive associando o efeito descrito na literatura como "quinta força"(que violaria o princípio de equivalência) com o movimento geodésico da geometria de Weyl integrável, reformulando o postulado geodésico. E, num segundo momento, usando o método variacional de Palatini, acabamos por formular uma nova teoria escalar-tensorial, agora com ingredientes completamente geométricos, ambientada numa geometria de Weyl integrável. Estudamos ainda soluções no vazio do problema estático de uma distribuição de massa esfericamente simétrica, onde surgem objetos de interesse astrofísico como singularidades nuas e buracos de minhoca. Também formulamos a teoria conhecida por WIST (Weyl Integrable Spacetimes) em (2 + 1)D, o que resulta numa teoria consistente, não sofrendo das falhas associadas à teoria da relatividade geral nessa dimensionalidade
27

Dopravní charakteristiky v uspořádání 2+1 / Traffic characteristics of 2+1 arrangement

Kabeš, Luboš January 2015 (has links)
The thesis discusses the roads in lanes 2 + 1 arrangement in the country and abroad. It focuses primarily analogy of this type of arrangement in our situation, ie on stretches of roads I. classes with an increased number of lanes for slow vehicles to climb. Part of this work is to verify some of the traffic, including traffic flow characteristics compared to conventional two-lane roads, especially in terms of: sectional speed; overtaking; Accident and dependence longitudinal gradient. The work aims to evaluate the foreign experience and achievements of domestic communications options for application configuration 2 + 1 in the Czech Republic.
28

A Study of Traffic Capacity with Regards to Heavy vehicle Share and Level of Service through Microsimulation / En kapacitetsstudie med avseende på lastbilsandelar och belastningsgrader genom mikrosimulering

Rickardsson, Johan January 2021 (has links)
The 2+1-road is a specific three lane road which aims to increase the safety of the predecessor 13 meter wide four lane roads. As a lane is removed and a weaving section is introduced the capacity is severely lowered, sometimes halved. A very demanding part of the traffic system with regards to capacity are heavy vehicles, especially in conjunction with the 2+1-roads. However, exactly how the share of heavy vehicles impacts the traffic system with regards to 2+1 roads and freeways is not previously studied, which grants the opportunity of this work. The work has been carried out in connection with an assignment from The Swedish Transport Administration of analyzing the E4 going north from Gävle. This study analyzes how the share of heavy vehicles and level of service affect the speed on the two types of roads. The Swedish Transport Administration currently bases their current relationships on speed, capacity, and level of service on a share of heavy vehicles of 12%, which may give slightly wrong results depending on which system is being analyzed. The study has been carried out through micro simulation, which is a method that is very dependent on what data it is given, such as behavioral parameters and other input. The results of the study show how the relationship between share of heavy vehicles and level of service affect the speed, and that the 2+1-roads are highly dependent on the share of heavy vehicles, whereas the freeways have much larger tolerances. / Den mötesfria vägen (s.k. 2+1-väg) tillkom på 90-talet och gav upphov till mycket mer trafiksäkra vägar än sina föregångare 13-metersvägarna från mitten av 1900-talet. Till följd av säkerhetsökningen kom uppoffringar i kapacitet i och med vävningssträckor, som mer än halverar kapaciteten i jämförelse med en tvåfilig väg. En mycket kapacitetskrävande del av trafiksystemet är lastbilar, framförallt i dessa vävningssträckor. Men exakt hur lastbilsandelar påverkar systemet är inte riktigt bearbetat än, vilket ger upphov till detta examensarbete. Studien har utförts i samband med ett uppdrag från Trafikverket angående simulering av E4:an norr om Gävle. Detta examensarbete granskar alltså hur lastbilsandelen och belastningsgraden påverkar punkthastigheten på de två vägtyperna mötesfri väg och motorväg. Trafikverket baserar sina effektsamband på en lastbilsandel på 12 %, vilket kan ge både för låga och för höga värden beroende på vilken plats som man granskar. Arbetet har genomförts med hjälp av mikrosimuleringsmodeller, vilka är mycket beroende av vilka parametrar och indata de får. Resultatet av studien visar hur punkthastigheten beror på lastbilsandel och belastningsgrad, och visar på att de mötesfria vägarna är mycket beroende av lastbilsandelen, medan motorvägar har betydligt större tolerans.
29

Sex Differences in Adolescent Depression

Hammarsten Yder, Emma January 2018 (has links)
At the age of 13, the 2:1 ratio becomes evident. It entails the fact that after puberty, twice as many females as compared to males suffer from depressive episodes. Much research has been conducted to highlight key contributing factors that aid in the onset and the timing of the 2:1 ratio. Many researchers emphasize hormonal influences and the onset of puberty as key contributors, with theories such as the gonadic theory andthe interactional hypothesis both highlighting the role of hormones in the existence and the emergence of the 2:1 ratio during adolescence. Furthermore, a large variety of researchers emphasize females increased stress sensitivity and stress reactivity as key contributors to the 2:1 ratio. Critically, research concerning hormonal- and stress-related factors will be included. However, an additional focus will be on neurodevelopmental sex differences. This, as brain-based sex differences have been paid too little attention in theories and models concerning the emergence of the 2:1 ratio during adolescence. Results from research conducted to unravel the mystery of sex differences within the adolescent brain emphasize the impact of sex hormones on the maturational sexual differentiation occurring within the adolescent brain. It has been hypothesized that increases in female adolescent depression might occur in accordance with upsurges in peripheral estrogen levels, during puberty. This seems to suggest that there is an interaction between the effects of circulating ovarian hormones in relation to both sexual differentiation in brain organization and depression susceptibility. Hence, the point of this essay is to delineate key contributing factors that potentially govern the existence and onset of the 2:1 ratio during adolescence by emphasizing the areas of (a) sex-based neurodevelopmental factors, (b) hormonal factors and (c) stress-related factors.
30

Chaos, Kingship, Councils, and Couriers: A Reading of Habakkuk 2:1-4 in its Biblical and Near Eastern Context

Haring, James W., III 03 September 2013 (has links)
No description available.

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