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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.
71

Vätgasdrivna arbetsmaskiners tekniska mognad : Dagens etableringsmöjligheter och potentiella tillämpningar i Gävleborgs framtida vätgassamhälle

Lärkfors, Selinn, Svedlund, Carolina January 2021 (has links)
Förbränning av fossila bränslen är den största orsaken till ökade växthusgasutsläpp i atmosfären som i sin tur ligger till grund för klimatförändringarna. Europeiska Unionen uttrycker klimatförändringarna som ett existentiellt hot och har som mål att Europa ska bli en klimatneutral kontinent till år 2050. Arbetsmaskiner, som vanligtvis drivs på diesel, är ett energikrävande fordonsslag vid användning som år 2016 stod för 6 % av Sveriges totala växthusgasutsläpp. Vätgas kan vara ett alternativt drivmedel till diesel eller andra fossila drivmedel för att minska de utsläpp som arbetsmaskiner ger upphov till. Syftet med studien är att uppmärksamma arbetsmaskiners roll i en omställning till vätgasdrift samt sprida kunskap om vad en omställning skulle innebära för dagens användare av arbetsmaskiner. Detta görs genom att belysa möjlig etablering i nutid av fem utvalda vätgasdrivna arbetsmaskiner samt gestalta dem i ett framtida vätgassamhälle. De arbetsmaskiner som inkluderas i studien är hjullastare, pistmaskin, sopmaskin, traktor och motviktstruck. Metoden består av en förenklad litteraturöversyn i kombination med personlig kommunikation samt en anpassning av verktyget Technology Readiness Level (TRL) i syfte att bedöma den tekniska mognaden. Resultatet visar att det i dagsläget finns etableringsmöjligheter i olika former för samtliga arbetsmaskiner i regionen baserat på TRL. Vätgasdrivna motviktstruckar och sopmaskiner är båda tillräckligt mogna tekniker för att etableras direkt på marknaden genom inköp. Vätgasdrivna hjullastare, traktorer och pistmaskiner är fortfarande under utveckling och kan därför etableras i regionen genom forskning och ytterligare utveckling eller först efter produktlansering på marknaden. De utvalda vätgasdrivna arbetsmaskinerna kan verka i ett framtida vätgassamhälle på liknande vis som motsvarande fossildrivna arbetsmaskiner gör idag med fördelar som mindre miljöpåverkan, vibrationer och buller som i sin tur medför mindre underhållsbehov med tillhörande kostnader. Resultatet visar att det finns möjligheter redan idag att påskynda en förändring, inte bara i Gävleborg utan i hela Sverige. De utvalda arbetsmaskinerna är verksamma inom branscher som motsvarar stora delar av det svenska näringslivet, en omställning till vätgasdrift kan därför ha en stor betydelse för en nationell reducering av växthusgasutsläpp. Det finns stor potential, särskilt för aktörer inom industrin, att upprätta egen vätgasproduktion och därmed bli självförsörjande på vätgas som drivmedel till arbetsmaskiner. Detta kan bli en av de radikala förändringar som enligt EU behövs för att uppnå målet om att åstadkomma klimatneutralitet år 2050. / Burning of fossil fuels is the biggest cause of increased greenhouse gas (GHG) emissions into the atmosphere, which in turn leads to climate change. The European Union expresses climate change as an existential threat and aims to make Europe a climate-neutral continent by 2050. Non-road machinery vehicles (NMV), which are usually powered by diesel, are an energy-intensive type of vehicle during usage that in 2016 accounted for 6% of Sweden's total GHG emissions. Hydrogen can be an alternative fuel to diesel or other fossil fuels in order to reduce the emissions that originate from NMVs. The aim of this study is to draw attention to the role of NMVs in a conversion to hydrogen operation and to spread knowledge about what a conversion would mean for today's users of work machines. This is done by highlighting possible establishment in the present of five selected hydrogen powered NMVs and illustrate them in a future hydrogen society. The NMVs included in the study are wheel loaders, snow groomers, street sweepers, tractors and counterbalanced forklifts. The method consists of a simplified literature review in combination with personal communication and an adaptation of the tool Technology Readiness Level (TRL) in order to assess technical maturity. The results show that there are establishment opportunities in the present in various forms for all NMVs in Gävleborg based on TRL. Hydrogen powered counterbalanced forklifts and street sweepers are both sufficiently mature technologies to be established directly in the market through purchasing. Hydrogen powered wheel loaders, tractors and snow groomers are still under development and can therefore be established in the region through research and further development or after product launch. The selected hydrogen powered NMVs can operate in a future hydrogen society similarly to fossil-fueled NMVs but with benefits such as less environmental impact, vibrations and noise which in turn entails less maintenance needs with associated costs. There are opportunities already today to accelerate a change, not only in Gävleborg but throughout Sweden. The selected NMVs are active in industries that correspond to large parts of the Swedish business community, a transition to hydrogen operation can therefore be of great importance for a national reduction of GHG emissions. There is great potential, especially for players in the industry, to establish their own hydrogen production and thereby become self-sufficient in hydrogen intended for NMVs. This could be one of the radical changes that, according to the EU, are needed to achieve the goal of accomplishing climate-neutrality by 2050.
72

Placement of Controls in Construction Equipment Using Operators´Sitting Postures : Process and Recommendations

Jalkebo, Charlotte January 2014 (has links)
An ergonomically designed work environment may decrease work related musculoskeletal disorders, lead to less sick leaves and increase production time for operators and companies all around the world. Volvo Construction Equipment wants to deepen the knowledge and investigate more carefully how operators are actually sitting whilst operating the machines, how this affects placement of controls and furthermore optimize controls placements accordingly. The purpose is to enhance their product development process by suggesting guidelines for control placement with improved ergonomics based on operators’ sitting postures. The goal is to deliver a process which identifies and transfers sitting postures to RAMSIS and uses them for control placement recommendations in the cab and operator environments. Delimitations concerns: physical ergonomics, 80% usability of the resulted process on the machine types, and the level of detail for controls and their placements. Research, analysis, interviews, test driving of machines, video recordings of operators and the ergonomic software RAMSIS has served as base for analysis. The analysis led to (i) the conclusion that sitting postures affect optimal ergonomic placement of controls, though not ISO-standards, (ii) the conclusion that RAMSIS heavy truck postures does not seem to correspond to Volvo CE’s operators’ sitting postures and (iii) and to an advanced engineering project process suitable for all machine types and applicable in the product development process. The result can also be used for other machines than construction equipment. The resulted process consists of three independent sub-processes with step by step explanations and recommendations of; (i) what information that needs to be gathered, (ii) how to identify and transfer sitting postures into RAMSIS, (iii) how to use RAMSIS to create e design aid for recommended control placement. The thesis also contains additional enhancements to Volvo CE’s product development process with focus on ergonomics. A conclusion is that the use of motion capture could not be verified to work for Volvo Construction Equipment, though it was verified that if motion capture works, the process works. Another conclusion is that the suggested body landmarks not could be verified that they are all needed for this purpose except for those needed for control placement. Though they are based on previous sitting posture identification in vehicles and only those that also occur in RAMSIS are recommended, and therefore they can be used. This thesis also questions the most important parameters for interior vehicle design (hip- and eye locations) and suggests that shoulder locations are just as important. The thesis concluded five parameters for control categorization, and added seven categories in addition to those mentioned in the ISO-standards. Other contradictions and loopholes in the ISO-standards were identified, highlighted and discussed. Suggestions for improving the ergonomic analyses in RAMSIS can also be found in this report. More future research mentioned is more details on control placement as well as research regarding sitting postures are suggested. If the resulted process is delimited to concern upper body postures, other methods for posture identification may be used.
73

From Diesel to Battery Power in Underground Mines : A Pilot Study of Diesel Free LHDs

Jäderblom, Niklas January 2017 (has links)
Load, haul and dump machines (LHDs) are commonly used in underground mines around the world. The machines are used to transport fragmented ore after blasting in the ore body. The main propellant used is diesel which accounts for a large part of the diesel consumed in mines today. This master thesis is a pilot study for further work to be done by LTU and Atlas Copco in a project called SIMS or Sustainable Intelligent Mining Systems, where the aim is to physically demonstrate diesel free LHDs doing productive work in mines. The objective of the thesis was to assess if the integration of battery-powered LHD machines is plausible in today’s underground mines. The aims were to map the current state of the production and to perform risk and job analysis of the new technology in the current systems. A theoretical framework was constructed with focus on safety, risk, hazards and change in work content. Social acceptance was then researched to be able to analyze how the new technology is received. Data gathering was done through interviews, observations, a focus group and reviewing documents while visiting Atlas Copco and two underground mines in Sweden. Diesel and electric-powered LHDs were studied in the mines and battery-powered LHDs were studied at Atlas Copco. The results present the current state of diesel, electric and battery-powered LHDs. How the machines are used in the visited mines and the identified risks with the work is presented along with the mapping of the battery system being developed by Atlas Copco. New risks that the battery system will bring to the work environment were identified using energy and deviation analyzes. The change in work content was discussed using the information from the visits and identifying what tasks will change, disappear and be added with the new technology. A large part of the thesis was analyzing the results with support from the theoretical framework. The analysis showed that a switch from diesel to battery-power would improve the overall health and safety inside the mines. A switch does not change the skill needed to operate the machines but can increase the qualifications for the service personnel. The main obstacles, in terms of social acceptance, with implementing the battery systems in the current state are that the need for constant battery exchange would cause problems in the production, the prejudice that the batteries would increase the consequences of a fire and the initial cost of making the switch. Recommendations for Atlas Copco going forward in the SIMS project were made. They need to emphasizing the safety of the technology to the users, developing the battery exchange so it can be done closer to the stopes and involve the operators in the projects of SIMS to help them understand the benefits it will have on them directly. / Gruvlastmaskiner (LHD) används ofta i gruvor runt om i världen. Maskinerna används för transportera fragmenterade malm efter malmen sprängts. Det huvudsakliga drivmedlet som används är diesel, som står för en stor del av den diesel som förbrukas i gruvor idag. Detta examensarbete är en pilotstudie för ytterligare arbete som ska utföras av LTU och Atlas Copco i ett projekt som heter SIMS eller Sustainable Intelligent Mining Systems. Syftet är att fysiskt demonstrera dieselfria LHD-maskiner göra produktivt arbete i gruvor. Syftet med examensarbetet var att bedöma om integrationen av batteridrivna LHD-maskiner är möjligt i dagens underjordiska gruvor. Målet var att kartlägga den aktuella produktionssituationen och att utföra risk- och arbetsanalyser av den nya tekniken i nuvarande system. En teoretisk referensram konstruerades med fokus på säkerhet, risk och förändring i arbetsinnehåll. Social acceptans undersöktes sedan för att kunna analysera hur den nya tekniken tas emot. Datainsamlingen gjordes genom intervjuer, observationer, en fokusgrupp och granskning av dokument givna vid besök på Atlas Copco och två underjordiska gruvor i Sverige. Diesel- och el-drivna maskiner studerades i gruvorna och batteridrivna studerades hos Atlas Copco. Resultaten presenterar det nuvarande läget för diesel, elektriska och batteridrivna LHDmaskiner. Hur maskinerna används i de besökta gruvorna och de identifierade riskerna med arbetet presenteras tillsammans med kartläggningen av batterisystemet som utvecklas av Atlas Copco. Nya risker med batterisystemet identifierades med hjälp av energi- och avvikelsesanalyser. Ändringarna i arbetsinnehåll diskuterades med hjälp av informationen från besöken och klargör vilka uppgifter som ska förändras, försvinnas och läggas till med den nya tekniken. En stor del av arbetet var att analysera resultaten med stöd från den teoretiska referensramen. Analysen visade att bytet från diesel till batterier skulle förbättra hälsan och säkerheten i gruvorna. Teknologibytet förändrar inte den färdighet som krävs för att kunna manövrera maskinerna men kan öka kvalifikationerna för servicepersonalen. De viktigaste hindren när det gäller social acceptans med att implementera batterisystemen i det nuvarande tillståndet är att behovet av konstant batteribyte skulle orsaka problem i produktionen, fördomarna om att batterierna skulle öka konsekvenserna av en brand och de initiala kostnaderna att göra ett byte. Rekommendationer för Atlas Copco för fortsatt arbete i SIMS-projektet gjordes. De behöver klargöra säkerheten hos den nya teknik för användarna, utveckla batteribytet så att det kan göras närmare produktionen och involvera operatörerna i SIMS-projekten för att hjälpa dem att förstå de fördelar som det kommer att ha på dem direkt.
74

Hydrostatický pohon pojezdu multifunkčního nakladače DAPPER / Hydrostatic drive of multi-purpose loader DAPPER

Vydra, Tomáš January 2015 (has links)
This thesis deals with design of hydrostatic drive for multipurpose loader and tool carrier DAPPER. At the beginning is research of different basic concepts and modern solutions to the problem, aided by a detailed description of competitive machine in the same performance category. Extensive comparison with other producers is included in the annexes to this thesis. Furthermore, a theoretical driving characteristic and its appropriateness is examined further on the basis of two model situations. The calculations of the individual components of the hydraulic circuit precedes drive kinematics analysis of articulated machine frame, on it final conception of hydrostatic drive is chosen. Firstly hydromotors and hydogenerator are chosen on the grounds of calculations then hydraulic hoses, filters and flow divider. Next chapters are aimed to calculations of hydraulic losses and thermal calculation of hydraulic circuit. Final part deals with introduction the final characteristics of drive. The practical parts of the work are assembly drawings with main power components and hydraulic schematic of drive.
75

Výstavba školy Rajhrad – stavebně technologická příprava / Construction of school Rajhrad – construction and technological preparation

Kijonka, Jakub January 2012 (has links)
Subject of this master thesis is the structural and technological background for the construction of high school in Rajhrad. This consists of time and finanical plans, technological instructions for the reinforced concrete monolithic skeleton, time schedule, item budget, construction site layout, machinery configuration , audit and evaluation plans, work place safety protocols, environmental plan of the construction site.

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