• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 4
  • 3
  • 2
  • 1
  • 1
  • 1
  • Tagged with
  • 13
  • 13
  • 4
  • 3
  • 3
  • 3
  • 3
  • 3
  • 2
  • 2
  • 2
  • 2
  • 2
  • 2
  • 2
  • 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.
1

Some aspects of the development of the metal trades in Ballarat 1851-1901

Cope, Graeme Stuart Unknown Date (has links) (PDF)
This thesis is an attempt to provide a special examination centering on some aspects on the development of metal processing and fabricating industries in the Victorian gold mining town of Ballarat from its foundation in 1851 to the end of its first half century in 1901. It is in effect a case study of a particular group of manufacturing activities made with the intention of improving general historians' understanding of the forces behind the establishment and growth of secondary industries in the non-metropolitan towns of nineteenth century Australia.
2

Development of twin screw Rheo extrusion technology

Cassinath, Zen January 2013 (has links)
Twin Screw Rheo Extrusion (TSRE) is a novel semisolid extrusion process developed at BCAST for producing simple profiles such as rods and wires of light alloys directly from melts with refined microstructures and improved mechanical properties. The process represents a shortened manufacturing route with great savings in investment, energy consumption and operation space. Research was carried out to investigate the feasibility of processing magnesium and aluminium alloys, to obtain the operations for the optimized microstructures and mechanical properties of the final product and to understand the mechanisms governing the evolution of microstructures. Experiments were conducted using an AZ91D magnesium alloy and several aluminium alloys on two specially made twin screw rheo extrusion machines and a range of conditions were tested. Results showed that the TSRE process was feasible for the AZ91D magnesium alloy and aluminium alloys, although modifications were required for processing aluminium alloys as the twin screw material used was found to react with aluminium. Analysis revealed that the extruded samples of both alloys had a uniform fine microstructure in both transversel and longitudinal directions and liquid segregation was limited, due to the application of intensive shearing during slurry making and extrusion. Low extrusion temperature was found to refine the structure and suppress the formation of the eutectic. The eutectic was easily dissolved upon heat treatment resulting in reasonable mechanical properties. Numerical analysis on thermal management was carried out and the results showed that a steady state thermal profile with a temperature gradient between the slurry feeding point and extrusion die could be established, promoting nucleation and preventing the formed solid particles from extensive growth during extrusion, which was confirmed by microstructural observations.
3

The research of Taiwan small and medium enterprise competitive advantage on transnational business ¡V An empirical study of traditional metal processing industries.

Lin, Wern-kuang 27 June 2007 (has links)
Since the early 1980, the economic development of Taiwan has mainly relied on the small and medium-sized businesses that steadily play the important roles in leading the development of globalization of Taiwan industries. However, under the trend of mergers and acquisitions between businesses and grandization of the enterprises, the operation of the small and medium-sized businesses has faced a tough challenge and competition from foreign businesses, especially the traditional metal processing industry, which forces the small and medium-sized businesses have to upgrade and transform themselves. Currently China has already become the global manufacturing plant and the international investment center in Asia. In 2002, Taiwan and China joined WTO at the same time; Taiwan metal processing manufacturing industry faces the serious cost competition from China and pincer attack of American-European brand advantage in global markets. Under this difficult situation, it is very important for Taiwan traditional manufacturing industries to find out the better way to survive in the competitive environment. For example, the metal processing manufacturers in Taiwan are facing tough competitions from foreign businesses in a bidding war for opportunity to do business in China. Is it important for Taiwan's economy that the small and medium-sized businesses can compete against those foreign competitors? The Taiwanese small and medium-sized companies must join force and work together to compete and stay competitive in global industries. Under the new structure of WTO and the agitation for industry globalization, it is important for Taiwan's metal processing industry to do research and come up with a solution to be more competitive in the international market so as to grasp its own transnational competition advantage. The relevant research institutes in Taiwan should make this issue a top priority since Taiwan resources are very limited compared to other countries like Europe, the United States and Japan. They must work together in all aspects of business and share with each other their resources and knowledge to stay competitive in the current situation. This research adopts the theoretical foundation approach and real cases study. Aiming to Taiwan's metal processing industry, I invited two top managers for the metal processing companies in south Taiwan to have deep discussion on the problems they have been facing. Through the interviews with the two managers, I learn their business plans on transnational investments, experiences in tactics planning and transnational management¡Ketc., by which this research will focus on the study of the advantage of transnational investment that would become the core target for the small and medium-sized businesses to create synergy. The points of the main theme include institutional framework, financing, industry development, technological innovation, and competition between China and foreign countries on the study and judgment upon advantage tactics, such as shutting and strategic alliance. Under the changeable situation that several new developing markets are open, and that the newly-developed countries join the global competition, this research consults the transnational enterprises about their overall arrangement of investment and experiences of management to make Taiwan numerous traditional industries and the small and medium-sized business have macroscopically global vision of management tactics. The forming of the market regional economy and trade competition directly influences the future fortune of numerous small and medium-sized enterprises in Taiwan. Taiwan small and medium-sized businesses must gradually adjust themselves to globalization trend and make corresponding strategies for it while Mainland China is positively expanding international trade and improving technology and quality through national economy projects.
4

Dimensionering och optimering av ett solcellssystem för en industribyggnad i Mellansverige : En simuleringsstudie

Östlund, Christine January 2019 (has links)
Vid omställningen till förnybara energisystem är solkraften som energikälla ett möjligt alternativ, för att uppnå klimat och energimålet med 100% förnybar energiproduktion år 2040. Detta är något regeringen eftersträvar genom infört bidrag i form av subventioner och skattereduktion vid installation av solceller. I denna fallstudie undersöks vilken effekt två olika solcellssystem har för en industribyggnad i Mellansverige, där studien tar hänsyn till ekonomisk-, teknisk- och klimatrelaterade aspekter. Systemen dimensioneras i strävan av optimala förhållanden samt av byggnadens begränsningar, med kostnadsförslag från en lokal återförsäljare få en bild av om återbetalningstiden är motiverande i frågan. Den lokala klimatpåverkan analyseras med växthusgasutsläpp i fokus, detta genom resultat av litteraturstudie. Dimensioneringen av solcellssystemen baseras på empiriskt material av studieobjektet och simuleras i programmet Winsun PV. Studien resulterade i två storlekar på system med tillhörande kostnadsförslag som ligger till grund för återbetalningstiden. System fall 1 dimensionerades i syfte att hålla den nominella systemeffektens storlek till 255 kWp, detta för att undgå extra energiskatt. Systemet gav ett årligt utbyte av 228 MWh/år som gav återbetalningstid mellan 18 – 22,5 år. Systemet simulerades med optimal lutningsvinkel av 39° i 15° azimutriktning av modulerna. System fall 2 dimensionerades till 1200 kWp i syfte att täcka effektivt användbar takyta, med årligt utbyte på 886 MWh/år och återbetalningstiden blev mellan 22,5 – 25,1 år. Modulerna simulerades med takets lutning ±4,7° i -15° azimutriktning. För att solceller ska ge ett mer lönsamt utbyte i högre latituder krävs en vidare effektivitetsutveckling för solcellstekniken samt ett förlängt investeringsstöd från Länsstyrelsen för framtida installationer. Om solcellssystemet ger en positiv inverkan på det ekologiska fotavtrycket beror av vart solcellen är tillverkad samt vilken elmix som byts ut mot den producerade solenergin. / When converting to renewable energy systems, solar power as an energy source is a potential option; in order to achieve the climate and energy goal with 100% renewable energy production in year 2040. This is something the government try to achieve by making installation of solar cells more attractive through allowances such as subventions and tax reduction. The aim of this study was to analyze the effect of solar cell system on an industrial building in the midst of Sweden, in regard of economical-, technical- and climate related points of view. This was performed by replacing purchased electricity with locally produced electricity, where optimal circumstances for the solar power systems and the limits of the building has been taken into consideration during the dimensioning. With cost suggestions from a local authorized dealer the magnitude of the pay off time as a motivating factor was estimated. The local climate impact will be investigated through a litterature study, focusing on green house gas emissions. The dimensioning of the solar cell systems were based on empirical input from measurements in combination with documented data regarding the industrial building and simulated in the program Winsun PV. The study resulted in two different-sized systems with cost sheets that formed the basis for the calculated pay off time. System case 1 was dimensioned to keep the size of the nominal system effect to 255 kWp, this to avoid extra energy tax. The system gave an annual exchange of 228 MWh / year which gave the repayment period between 18 - 23 years. The system was simulated with an optimum angle of 39 ° in 15 ° azimuth direction of the modules. System case 2 was dimensioned to 1200 kWp in order to cover the effective usable surface of the roof, the system gave an annual exchange of 886 MWh / year and the repayment period was 22.5 - 25.1 years. The modules were simulated with the roof slope ± 4.7 ° in -15 ° azimuth direction. A further efficiency development for solar cell technology is required as well as an extended investment support from the County Administrative Board, to provide a more profitable exchange of solar cell systems in higher latitudes. If the solar cell system has a positive effect on the ecological footprint depends on where the solar cell is made and which electrical mix replaced by the produced solar energy.
5

Simulative Untersuchung vibrationsbasierter Ausrichtkonzepte für Rohblechtafeln

Müller, Elisabeth, Risch, Thomas, Golder, Markus 12 October 2021 (has links)
Für die effiziente Blechtafelbearbeitung mit hoher Prozesssicherheit und Teilequalität ist die positions- und winkelgenaue Ausrichtung der Rohblechtafeln vor dem Bearbeitungsprozess erforderlich. Dieser Beitrag untersucht vibrationsbasierte Ausrichtkonzepte mittels Mehrkörpersystem-Simulation. Die entwickelten Simulationsmodelle ermöglichen die Charakterisierung und den Vergleich der Konzepte hinsichtlich der Bewegungs- und Ausrichteigenschaften sowie der erforderlichen Antriebskraft. / Efficient, reliable, and qualitative sheet metal processing requires both positional and angular alignment of the raw metal sheets prior to the manufacturing process. This paper investigates different vibration-based alignment concepts using a multi-body system simulation. The simulation model is then used to characterize and compare, with respect to the motion and alignment properties as well as the required driving force, the diverse vibration-based alignment concepts.
6

Detailní projektování technologického pracoviště ve firmě Kovot Invest s.r.o. / Detailed project proposal of a technological workplace in the company Kovot Invest s.r.o.

Tichý, Jan January 2017 (has links)
The diploma thesis deals with the design of a new production hall for sheet metal processing in KOVOT Invest s.r.o. The content of the thesis is the analysis of the current state, the capacity calculations of individual technologies and warehouse management. Further design of the layout solution in the hall and economic evaluation of the investment.
7

Experimentelle Untersuchung vibrationsbasierter Ausrichtkonzepte für Rohblechtafeln

Müller, Elisabeth, Risch, Thomas, Golder, Markus 25 March 2022 (has links)
Effizienz, Prozesssicherheit und Teilequalität in der Blechtafelbearbeitung erfordern die exakte Positionierung der Rohblechtafel zur Bearbeitungsmaschine. Dieser Beitrag beschreibt die experimentelle Erprobung vibrationsbasierter Ausrichtkonzepte an einer eigens entwickelten Versuchsanlage. Die Versuchsergebnisse führen zur Identifikation einer Vorzugslösung sowie möglicher Stellgrößen des Ausrichtprozesses. / Efficiency, process reliability and part quality in sheet metal processing require the precise positioning of the raw sheet metal to the processing machine. This paper presents the experimental investigation of vibration-based alignment concepts in a dedicated test facility. The test results enable identification of a preferential solution as well as possible control parameters of the alignment process.
8

Effektivisering av tillverkningsprocess med mjukvara för nesting / Effectivizing a manufacturing process with nesting software

Lundgren Akbarzadeh, André January 2023 (has links)
Rapporten presenterar ett examensarbete vid Kungliga Tekniska Högskolan, utfört på ett företag i skylttillverkningsindustrin. Syftet med examensarbetet är att undersöka om produktionen på det uppdragsgivande företaget kan effektiviseras genom att ersätta ett manuellt arbetsmoment med en automatiserad lösning i form av en mjukvara. Det undersöks även om, och i sådant fall hur stora förbättringar som kan göras i processen sett till ekonomisk, ekologisk och social hållbarhet. Genom att undersöka marknadens utbud av mjukvaror för nesting och jämföra mjukvarornas egenskaper mot definierade krav kunde en handfull mjukvaror konstateras vara relevanta. Testprogramvaror begärdes för dessa, och i de fall de erhölls så testades mjukvarorna på rådata från projekt som företaget tidigare tillverkat i syfte att jämföra resultaten. Skillnaderna i resultat beräknades och jämfördes med resultaten av det manuella arbetssättet. Det konstaterades att användning av den bäst presterande mjukvaran kan spara företaget i snitt 481 kronor per projekt i minskad material- och tidsåtgång. Vidare beräknades att företaget hade kunnat spara drygt 28 kg material på de fem projekten som tillverkades i aluminium, för vilka bara återvinningen hade kostat ca 2,25 kg koldioxidekvivalenter per projekt. Nyproduktionen av denna aluminium uppskattas motsvara mellan 16,6 – 36,2 kg koldioxidekvivalenter per projekt. / This paper presents a bachelors thesis at the Royal Institute of Technology, performed at a company in the sign manufacturing industry. The aim of the thesis is to investigate if the production at the company can be made more effective by replacing a part of the process that requires manual work with an automated solution in the form of a software. It is also investigated whether changes in the process can result in improvements in economical, ecological and social sustainability, and in that case the greatness of the improvements. By conducting market research of nesting software and comparing the properties of the software to pre-determined requirements, a handful of different software were considered potentially applicable. Software for testing were requested for these, and tests were conducted with those that were obtained. The tests were conducted on raw data from previously manufactured projects at the company in order to compare the results. The differences in results were calculated and compared with those of the manual process. It was concluded that the top performing software could render the company an average of 481 kronor saved per project in terms of time saved and material usage. Furthermore, calculations showed that the company could have saved over 28 kg worth of material for the five projects where aluminium was used. For these projects, the recycling of the aluminium would be equivalent to 2,25 kg carbon dioxide equivalents per kg, per project. The production of new aluminium for these projects would equate to an estimated 16,6 – 36,2 kg carbon dioxide equivalents per kg, per project.
9

Identifying incentives & discouragements to understand how a Scope 3 boundary could be set : A case study on a metal processing company

Babikian, Arziv, Fagrell, Alexander January 2021 (has links)
Purpose: The purpose of this study is to identify incentives and discouragements thus providinga better understanding of how metal processing companies could set their Scope 3 boundary. Method: To achieve the purpose of the study, a qualitative case study with an inductive approach was used. The studied company was a global metal processing company that was working towards setting a Scope 3 boundary, and the data consists of semi-structured interviews that were gathered from both internal and external stakeholders. Findings: Firstly, the findings presented, highlight incentives that affected companies in the metal processing industry to pursue setting a Scope 3 boundary, namely incentives that are categorised into 1) Improved corporate environmental reputation, 2) Increased competitive advantage, and 3) Financial gains. The discouragements found were categorised into 1) High uncertainty, 2) Immature industry/technical solutions, and 3) Low influence outside of the organisational boundary. These incentives and discouragements were analysed to show how they affected the Scope 3 boundary. This resulted in an industry-specific guideline on how companies in the metal processing industry could set their Scope 3 boundary. Theoretical contribution: The findings prolong earlier research by defining incentives and discouragements in a Scope 3 context. A theoretical contribution from this study was that regulations might inhibit some of the Scope 3 incentives. The findings indicate that drivers to benchmark against other stakeholders, such as differentiating from competitors and improved corporate sustainable reputation. A non-regulatory market environment is, therefore, fostering these incentives, which could be useful to acknowledge in further studies in a Scope 3 context. Practical implications: This study provides an enhanced understanding of how metal processing companies can set their Scope 3 boundary based on what set of incentives or discouragements that drives them. It is also important for companies to understand incentives and discouragements that may change (e.g., regulations towards Scope 3 emissions) in time, which would result in different Scope 3 boundaries. Also, this understanding of what incentives and discouragementsaffecting the boundary-setting could benefit policymakers in their work improving the Scope 3 discouragements.
10

Hot rolling friction control through lubrication / Contrôle du frottement dans le laminage à chaud à l’aide de la lubrification

Bertrand, Loïc 16 June 2017 (has links)
Cette thèse porte sur l’amélioration du laminage à chaud, un procédé de fabrication sidérurgique permettant de transformer une brame de métal (10m de long, 1.5m de large et 250mm d’épaisseur) en une bande de tôle bobinée (1000m de long, 1m de large et 2mm d’épaisseur). Afin d’obtenir certaines propriétés mécaniques et de faciliter la phase de laminage, la brame est réchauffée à 1300°C et dégrossi avant d’être envoyé vers le train finisseur où elle est laminée en passant successivement dans plusieurs cages (ensemble de cylindres qui écrasent le métal) et qui permettent de réduire l’épaisseur à la valeur finale souhaitée. Le produit est finalement refroidi puis bobiné avant d’être envoyé au client. La thèse se focalise sur l’amélioration du train finisseur en proposant un contrôle du frottement entre la bande et les cylindres de travail à l’aide d’une lubrification. La lubrification consiste à déposer de l’huile sur le cylindre en vaporisant une émulsion d’eau et d’huile. L’huile déposée modifie l’interface entre la bande et le cylindre et diminue le coefficient de frottement. Cette diminution du coefficient de frottement a plusieurs avantages : elle permet de réduire l’usure des cylindres, d’améliorer l’état de surface de la bande, de réduire l’effort nécessaire de laminage donc la consommation d’énergie et d’augmenter la capacité du train. A l’inverse, un frottement trop bas dû à une lubrification trop importante peut causer un patinage de la bande entrainant l’arrêt du train. Il est donc important de contrôler le niveau de frottement de manière sécurisée. La conception du contrôle s’est faite à travers deux principales étapes : La modélisation et l’identification de l’effet de la lubrification sur le coefficient de frottement, la conception du contrôle du frottement / This thesis is about the improvement of the hot rolling process. This steelmaking process turns a slab (10m long, 1.5m wide, 250mm thick) into a coiled strip (1000m long, 1m wide, 2mm thick). To obtain some metallurgical properties and to make the rolling easier, the slab is heated up to 1300 ° C and roughly rolled before going to the finishing mill. In the finishing mill the strip is rolled through successive stands (set of rolls) to reduce the thickness to its final desired value. The product is finally cooled down and coiled before shipping it to the customers. The thesis focuses on the enhancement of the finishing mill through a friction control between the strip and the work rolls using lubrication. The lubrication consists in building up oil on the rolls by spraying an emulsion of water and oil. The deposited oil changes the contact interface between the strip and the roll and decreases the friction coefficient. The reduction of the friction presents the advantages of: reduce the roll wear, enhance the strip surface quality, decrease the rolling force (reduce then the energy consumption) and increase the mill capability. In the other hand, an insufficient amount of friction due to an overabundance of lubrication can induce a slippage of the strip leading to a stop of the mill. It is important to control the amount of friction in a secure way. The design of the controller was done through two main steps: Modeling and identification of the effect of lubrication on the friction coefficient, designing the friction control

Page generated in 0.1119 seconds