• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 22
  • 9
  • 6
  • 2
  • 2
  • Tagged with
  • 50
  • 15
  • 9
  • 9
  • 7
  • 6
  • 5
  • 5
  • 5
  • 5
  • 5
  • 5
  • 4
  • 4
  • 4
  • 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.
11

RR PLC Application Code : a Benchmark Study

Kihlström, Andreas, Weivert, Joakim January 2009 (has links)
This degree thesis is performed at Rolls-Royce at the Control Systems division. The assignment is to compare two different PLC development tools and determine how a transition toa new PLC development tool would be. The programs that will be compared is the current toolAutoCAD with the extension ACG and CoDeSys. A transition from AutoCAD to CoDeSys is realizable but will take considerable time and effort. Theeasiest way to achieve this is to during the transition generate an export file from the existing drawingsin AutoCAD which then can be imported to CoDeSys. By this CoDeSys can be used as a platform fordeveloping. This is fully realizable because ACG which generates the C code can be modified togenerate almost any export file.
12

Statistical analysis of deterministic textures in steel sheet production

Porrino, Alessandre January 2004 (has links)
Textured surfaces are universally adopted in the steel sheet production industry, and manufacturers are continuously improving the quality of the finished products through intense research in the surface characterisation field. Deterministic Surfaces are textured with specifically designed rolls in order to present a certain degree of regularity, which allows better control over the functional behaviour of the metal sheets. The regularity of the texture impressed on the steel sheets also allows unconventional approaches to surface characterisation and to the assessment of the texture's structure. Statistical analysis is the most effective way to target the isolation of the deterministic part of the surface, which represents the desired product, from the stochastic part, called ‘noise’ and associated with the inaccuracies of production and measurement. This work addresses the problem of characterisation of deterministic textures through statistical analysis, proposing innovative filtering techniques aimed at the realisation of an On-line Process Control System. Firstly the techniques proposed are theoretically formulated and studied, addressing in particular the physical meaning of the geometrical parameters extracted through statistical analysis of highly correlated portions of the textures. A method for isolating the deterministic textures present on a surface, called the Statistical Surface Filter, is presented and discussed in detail, and tested on existing laboratory samples. Secondly the filter is applied to preliminary measurements acquired by an innovative on-line measurement system currently under development, and evidence is shown that the technique is effective in separating the information regarding the regular patterns from the stochastic noise. The possible applications to on-line Statistical Process Control are discussed. Thirdly, the Statistical Surface Filter is tested on a set of measurements representing texturing rolls and textured sheets with different characteristics; statistical analysis of the surface parameters extracted from the filtered surfaces show that the technique allows the assessment of the different contributions of the various stages of the texturing process to the final product. Finally, a software package is implemented for the practical application of the filtering techniques and the parameters extraction; the algorithms that perform the statistical filtering are described and discussed, concluding with the operations of optimisation and fine-tuning for production-line implementation.
13

RR PLC Application Code : a Benchmark Study

Kihlström, Andreas, Weivert, Joakim January 2009 (has links)
<p>This degree thesis is performed at Rolls-Royce at the Control Systems division.</p><p>The assignment is to compare two different PLC development tools and determine how a transition toa new PLC development tool would be. The programs that will be compared is the current toolAutoCAD with the extension ACG and CoDeSys.</p><p>A transition from AutoCAD to CoDeSys is realizable but will take considerable time and effort. Theeasiest way to achieve this is to during the transition generate an export file from the existing drawingsin AutoCAD which then can be imported to CoDeSys. By this CoDeSys can be used as a platform fordeveloping. This is fully realizable because ACG which generates the C code can be modified togenerate almost any export file.</p>
14

Development of a practical software tool for the design of rolls for near net shape profile rolling

Fischer, Christian E. January 1994 (has links)
Thesis (M.S.)--Ohio University, March, 1994. / Title from PDF t.p.
15

Caracterização de materiais utilizados na fabricação de cilindros de laminação submetidos ao desgaste abrasivo

Cornélio, Gilson Teixeira [UNESP] 20 January 2006 (has links) (PDF)
Made available in DSpace on 2014-06-11T19:28:34Z (GMT). No. of bitstreams: 0 Previous issue date: 2006-01-20Bitstream added on 2014-06-13T20:58:34Z : No. of bitstreams: 1 cornelio_gt_me_guara.pdf: 7494292 bytes, checksum: 4665b80734a19910838d0896e5face70 (MD5) / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / O avanço da tecnologia de laminação incrementou as solicitações sobre os cilindros laminadores, e, portanto, o desenvolvimento de materiais mais resistentes ao desgaste, visando aumento da produtividade do laminador e melhor qualidade superficial dos produtos laminado, em especial tiras a quente. Como estudo de desgaste em campo é muito complexa devido à influência de diversos mecanismos e muitas vezes combinados entre si, os ensaios laboratoriais têm se mostrado como um meio mais fácil para estudar os materiais em serviço, além de auxiliar o projeto novas ligas. Dessa forma, foi proposto um ensaio de desgaste abrasivo puro para um tribômetro Plint & Partners, modelo TE-079, com o intuito de simular condições de utilização das últimas cadeira do trem acabador de um laminador de tiras a quente. Para sua validação foram utilizados três materiais: o ferro fundido de coquilhamento indefinido, o ferro fundido branco de alto cromo e o ferro fundido branco multicomponente, os quais apresentam comportamento conhecido em serviço. Esses materiais foram submetidos a uma caracterização metalográfica, microdureza e topografia de desgaste. Os resultado obtido mostraram-se coerentes com a prática observada na aplicação real, ou seja, reproduziram o comportamento de desgaste no laminador, sendo válida a proposta do ensaio tribológico. / The progress towards mill technology has increased the demand on the rolling mill rolls, and therefore, the development of wear resistant seekink productivity of the rolling mills and better superficial quality of the rolled products, especially in the hot strip mill has also increased. As the wear study in field is very complex due to the influence of several mechanisms wish are usually combined amongst themselves, the labs test have shown an easy way to study the materials in service, besides aiding the project of new leagues. In that way, a pure abrasive wear test was developed tribômetro Plint & Partners, model TE-079 with the intent of simulating the job conditions in the hot strip mill finishing chairs. For the validation three materials were used: an indefinite chill cast iron, a high chrome cast iron and a kind of multicomponent white cast iron, which presents knowm behavior in service. Those materials were submitted to a metallography characterization, microhardness measurement and wear topograpy observation. The obtained results were shown coherent with the practice observed in the real application, and then became possible a prediction of that behavior for the materials projects developed at laboratory, being valid the proposal of the rehearsal tribológico.
16

Análise de variáveis dinâmicas na fundição centrifugada de cilindros de laminação

Gonçalves, Camilla Gandine [UNESP] 16 December 2011 (has links) (PDF)
Made available in DSpace on 2014-06-11T19:28:33Z (GMT). No. of bitstreams: 0 Previous issue date: 2011-12-16Bitstream added on 2014-06-13T20:18:22Z : No. of bitstreams: 1 goncalves_cg_me_guara_parcial.pdf: 217661 bytes, checksum: c20902856040fbee187ead0ee3cb00b5 (MD5) Bitstreams deleted on 2015-06-25T13:01:15Z: goncalves_cg_me_guara_parcial.pdf,. Added 1 bitstream(s) on 2015-06-25T13:03:30Z : No. of bitstreams: 1 000679599_20151231.pdf: 217896 bytes, checksum: cf025ea71faace9e52cbc1051e6f88a1 (MD5) Bitstreams deleted on 2016-01-04T10:26:26Z: 000679599_20151231.pdf,. Added 1 bitstream(s) on 2016-01-04T10:28:17Z : No. of bitstreams: 1 000679599.pdf: 1039378 bytes, checksum: fb5a9506ef24ceed88e78978a6f9f073 (MD5) / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / Este estudo mostra as variáveis dinâmicas do processo de fundição centrífuga de cilindros de laminação, que são utilizados para realização de conformação em gaiolas de laminação. O objetivo desse estudo é analisar as principais variáveis dinâmicas do processo de fundição centrifugada de cilindros de laminação e estudar as relações entre estas variáveis. Os processos de fundição centrífuga podem ser classificados em fundição centrífuga vertical e horizontal. Para a fundição centrífuga vertical, são elaborados os envelope de carga de dois modelos de máquinas centrífugas verticais existentes na literatura, onde se consegue determinar o tipo de rolamento de apoio utilizado na máquina. Para a fundição centrífuga horizontal, são estudadas variáveis como rotação, razão G, “aspect ratio”, espessura e vibração de uma amostra de aproximadamente 1.000 cilindros de ferro fundido, aço rápido e aço alto cromo. Desta amostra, verifica-se que a causa de sucateamento de parte dos cilindros não está ligada a adoção de variáveis dinâmicas incorretas no processo. Também é visto que diferentemente do alumínio, os cilindros de ferro fundido, aço rápido e aço alto cromo exigem maior rotação quanto maior a espessura da casca fundida. / This paper shows the dynamic variable of centrifugal casting process of rolling mill rolls which are used to compress the metal in rolling mill process. The main goal is to analyze the main dynamic variable and to study its relation in the process. There are two type of centrifugal casting: horizontal and vertical. For the horizontal centrifugal casting, two load envelopes are done, being possible to determine the bearing model used on the vertical centrifugal casting machine. For the horizontal centrifugal casting, variable such as rotating, ratio G, aspect ratio, thickness and vibration are studied to a sample of 1,000 casting rolls made of casting iron, high speed steel and high chromium steel. From this sample, it is seen that the cause of scrapping is not related to incorrect adoption of dynamic variables in the process. It is also verified that differently from the aluminum, cast iron, high speed steel and high chrome steel rolls demand greater speed with the increasing the shell casting thickness.
17

Development of a practical software tool for the design of rolls for near net shape profile rolling

Fischer, Christian E. January 1994 (has links)
No description available.
18

Cloud Streets. A Study of the Instability Mechanisms Giving Rise to Boundary Layer Rolls / Molngator - En studie över hur molnrullar uppkommer i gränsskiktet

Bergstedt, Josefine January 2020 (has links)
Boundary layer rolls are a rather frequent phenomena, where regions of alternating up- and downdraft motion causes clouds to form in elongated, parallel rows oriented with the mean wind direction. The clouds can be seen during certain atmospheric conditions and are often called ”cloud streets” because of their characteristic appearance. By performing a linear instability analysis, the underlying mechanisms causing the onset of boundary layer rolls has been analysed in this study. There are two governing mech- anisms that cause the boundary layer rolls to form, the thermal instability and the dynamic instability. The thermal instability is caused by convection in an unstable airmass, while the dynamic instability usually is associated with neutral or stable conditions. The dynamic instability arise due to an inflection point in the wind profile, around which eddies develop. In a previous study by Svensson et al. (2017), rolls were observed over the Swedish east-coast, stretching out over sea during four days; 2 of May 1997, 3 of May 1997, 17 of May 2011 and 25 of May 2011. The aim of this study is to simulate the rolls on these four dates, analyse the underlying mechanisms and establish what type of instability that primarily causes the rolls to form. The linear stability analysis performed in this study indicate that the dynamic instability is the main mechanism giving rise to the rolls on all four studied dates. The rolls are found to arise over the Swedish mainland and are advected out over the sea. Both the orientation of the rolls and the modeled wind direction are in accordance with the observations. A qualitative agreement is found for the wavelength, the amplitude and the altitude of the rolls, when comparing the results of this study with the observations.
19

Effects of Whey Protein Concentrate, Phosphate, and Sodium Hydroxide on Texture and Acceptability of Turkey and Beef Rolls

Moiseev, Igor V. 01 May 1994 (has links)
Processed turkey rolls were prepared with 1 or 3% whey protein concentrates WPC-50 (pH=5.80), WPC-60 (pH=4.53) and WPC-75 (pH=6.85} containing 50, 60 and 75% protein along with controls (phosphate and no phosphate). Control rolls made with 0.5% phosphate had the highest bind strength, and sensory evaluation scores. Only WPC-75 (1%) was acceptable as a binding agent and flavor enhancer. WPC-60 reduced pink discoloration of rolls, but flavor, bind and cohesiveness scores were unacceptably low. WPC-50 was not an effective binding agent. In general, rolls made with 3% WPC had lower scores for intensity of turkey flavor. Bind strength and sensory characteristics were compared for restructured beef rolls formulated with 1% salt, 0.375% sodium tripolyphosphate (STPP) or O. 07 % sodium hydroxide (NaOH), and 5, 10 or 20% added water. Controls also had 1% salt, but no STPP or NaOH. Relative bind strength of rolls was STPP > NaOH > controls. Addition of 20% water reduced bind strength. Cooked yield, moisture content, beef flavor and texture of NaOH rolls were similar to STPP rolls. Bind strength and cohesiveness of NaOH rolls were lower than STPP rolls, but still acceptable. For measuring bind strength of turkey and beef rolls, a sensitive and inexpensive penetrometer was developed. It was equipped with a top-loading balance, accessories, IBM-compatible personal computer and Quick-Basic program that allowed continuously collected penetration force data . at specific time intervals. Penetrometer bind strength and taste panel cohesiveness of turkey and beef rolls were highly correlated (r=0.89 and r=0.93, respectively).
20

Materialhantering för tvärjärn till band för skogsmaskiner från Olofsfors AB / Material handling for cross member for forestry machine tracks from Olofsfors AB

Stenlund, Martin January 2021 (has links)
Olofsfors AB arbetar med tillverkning av band och slirskydd till gummihjulsburna skogsmaskiner. Företaget vill idag implementera en ny profil på tvärjärn som de vill kunna köra i deras linje. Problemet är att den nya profilen de vill implementera har samma bredd som deras transportörrullar. Transportören behöver vara lite bredare än tvärjärnet så det finns kanter på båda sidorna av rullarna. Detta säkerställer att de inte hamnar snett utan åker centrerat genom linjen. Projektet går ut på att utreda rullkretsen och se om det finns möjlighet att göra om transportörrullarna eller hitta en annan lösning på om det går att göra om linjen helt.  Metoden som använts har varit att göra en nulägesanalys, intervjuer och undersöka om det fanns några tidigare projekt om detta. Två lösningsförslag tas fram. Företaget kunde använda sig av en glidskena i början av rullkretsen istället för transportörrullar. Efter värmarna som värmer uppstålet gör man två separata glödskalsrensare där den ena är för smalt/special tvärjärn och den andra för bredare tvärjärn. Genom att använda två olika glödskalsrensare kan man optimera borttagandet av skal som bildas på stålet för de olika profiler man kör genom linjen. Det andra förslaget visar att det går att fortsätta med de befintliga rullarna de har idag och endast bredda hela linjen för att få plats med det nya tvärjärnet. / Olofsfors AB is producing tracks and chains for rubber tired forest machines. The company wants to implement a new sort of profile for their wheel tracks. The problem is that the new profile has the same width as the conveyor rolls in the machine. The conveyor rolls must be wider than the cross member on both sides. This prevents the cross meber from tilting and to secure that it´s going straight and centered through the entire line. The project is focusing on a possibility to change the conveyor rolls for the company wheel track lines or see if there is a solution to change the entire line to solve the problem.  The method that has been used to solve the problem was to do a current situation analysis, interviews, and research if there was any earlier project about this. Two potential solutions were presented. The most promising solution seems to be the implementation of a slide rail in the beginning of the line instead of conveyor rolls. Behind the oven that heats the cross member, two separate spray nozzles for surface treatment are constructed, where one is for the more narrow cross member, and the other is for wider cross member. The benefit of using two separate spray surface treatment is the optimization of spray surface treatment on the different profiles that are produced more efficiently. However, the work shows that it is also possible to produce the new tracks using the exiting conveyor rolls. / <p>Pågrund av pandemin ägde presentationen rum på Zoom. </p>

Page generated in 0.0913 seconds