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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.
1

Machine rental in the construction industry: The decision to own or rent from a machine rental company / Maskinuthyrning inom bygg- och anläggningsbranschen: Beslutet om att äga eller hyra hos en maskinuthyrare

Crnic, Ena, Mattsson, Michaela January 2022 (has links)
Företaget Renta AB AB är ett maskinuthyrningsföretag som hyr ut maskiner till stora bygg- och anläggningsföretags byggprojekt. Det kan vara företag som Skanska AB, Kanonaden Entreprenad AB och NCC, men maskinerna kan också hyras av privatpersoner. Företaget finns etablerat i Sverige, Finland, Norge, Polen och Danmark. Renta AB har maskiner som de själva äger och hyr ut. Under vissa säsonger förändras efterfrågan och för att kunna möta kundens behov hyr Renta AB maskinerna från en leverantör och hyr sedan ut maskinerna från sitt företag. Liksom andra företag strävar Renta AB efter att uppnå så hög lönsamhet som möjligt, vilket ställer krav på en god kännedom om vilka maskiner som bör efterfrågas av deras kunder. Detta innebär också att Renta AB måste ta beslut om att äga eller hyra maskiner för att göra så lönsamma investeringar som möjligt. Syftet med studien är att utvärdera vilka maskiner Renta AB bör äga respektive hyra med hjälp av investeringskalkyl. En prognostisering genomfördes för att få fram hur efterfrågan kommer se ut för 16 utvalda artiklar under dess ekonomiska livslängd. Baserat på prognostiseringen användes internräntemetoden för att jämföra kapitalvärdet för att äga maskiner respektive hyra in maskiner från en leverantör. En jämförelse gjordes för att kunna ta ett beslut vilka maskiner som bör ägas respektive hyras för att få ett så högt kapitalvärde som möjligt. Resultatet visade att av de 16 utvalda artiklarna bör elva ägas och resterande hyras. En maskin utmärkte sig extra mycket genom att den bidrar till en skillnad på 1,6 miljoner kr vid att äga tillskillnad från att hyra. Det fanns även vissa maskiner som inte bidrog till lika stor skillnad i kapitalvärde vilket beslut som än togs. Vad som bidrar till att kapitalvärdet ser olika ut är grundinvesteringen, kassaflödet, den ekonomiska livslängden och kalkylräntan. De kvantifierbara siffrorna diskuterades med Renta AB och vissa maskiner som rent ekonomiskt inte är värda att behålla finns ändå kvar bland deras utbud för att kunna erbjuda sina kunder dessa. Det kan vara maskiner som inte finns längre på marknaden eller som är väldigt dyra att investera i. Det fanns även andra faktorer som påverkade huruvida företaget valde att äga eller hyra maskinerna, exempelvis tillgång på lagerplatser eller att de endast användes under vissa säsonger. / <p>Examensarbetet är utfört vid Institutionen för teknik och naturvetenskap (ITN) vid Tekniska fakulteten, Linköpings universitet</p>
2

Modular Communications Relay for Autonomous Quarry Operation

Knutsson, Simon, Larmark, Daniel January 2018 (has links)
Today’s quarries face a change in the operational processes, where the development of automated transport systems and machines have intensified the necessity for reliable and stable data transfer. Within the dynamic environment, with piles building up suddenly, frequently changing mining faces due to blasting, as well as a frequently changing general environment that affect the network coverage negatively, there is a need for a solution that can adapt to the changing environment. The aim of this research has been to investigate the requirements for a dynamic infrastructure, and develop a platform based on today’s available technical solution components that can act as a dynamic platform for the evolving autonomous quarry. This by also reducing the time the worker is exposed to the harsh environment that the quarry presents. The research was conducted through a combination of a product development strategy and Design Research Methodology to develop a concept that fulfills the customer needs that are identified. An iterative process, where the needs were translated in to prototypes, has created learnings through every step of the development process. The result is a relocatable platform for communications relay, which is mounted on a trailer with a fixed mast to distribute short-wave communications in the area where the mobile unit is needed. The trailer is equipped with a four-point leveling system that also act as a stabilization system for the unit and ensures that the platform maintains a horizontal plane at all times. This platform is a first step towards a fully autonomous management of the communication infrastructure which in the future will be needed when a stable process and connection is necessary in the frequently changing environment. The relocatable platform is a necessity for adaption of the short-wave communication in the constantly changing environment. Since this is a first iteration and concept in the development of a dynamic platform, extensive field tests are required to determine which subcomponents are in need of further development or optimization. The completed prototype for the platform is functional and field ready for further testing in its real environment for further collecting of data points. This concept is a subcomponent of a larger system, where the goal is to increase the productivity and reduce the environmental impact from today’s quarry industry. Through reduction of human interaction and management of the relocation of the mobile unit, the workers safety is increased and the harsh environmental exposure is reduced.
3

Enclosing and Mounting an Electronic Component on Articulated Haulers : A proposition on how to protect, and where to place, an intelligent node on the environmentally harsh exterior of construction equipment with respect to multiple parameters

Sintorn, Johan January 2016 (has links)
As is the case with many other manufacturers of vehicles, Volvo Construction Equipment has a constantly increasing amount of electric and electronic equipment in their articulated haulers. These are of great use in modern machines, bringing functions, and safety that were not possible before, but they also bring more cables to handle. In the case of the articulated haulers a quite thick cable harness of about 15 meters in length reaches from the driver’s cabin in the front to the components in the far back end of the vehicle. This is not only a lot of long cables to handle both during assembly and service, but the nature of signals traveling in cables is that the voltage gets weaker with distance. This phenomenon has to be accounted for by measuring devices dependent on the voltage. It has been suggested that a device referred to as an intelligent node, or ICCS-module, which communicates digitally via CAN could be installed in the back of the articulated haulers. This module would be independent of the mentioned drop in voltage. The ICCS-module will be receiving a small bundle of cables being routed from the driver’s cabin. From it cables would go out to a majority of the components in its vicinity. The components connected to the node would not need to have any other cables. This thesis is focused on the mechanical aspects of installing this ICCS-module. Having electric and electronic equipment on construction vehicles is a challenge when it comes to protecting the device from the harsh environment that is the hauler’s exterior. It will have to withstand being immersed in water for long periods of time, greatly varying temperatures, vibrations and shocks as well as being hit by projectiles. The placement as well as the design of the enclosure should be chosen with respect to both the devices length of life and how well it fulfils its intended role and achieves the expected results. To produce an enclosure and find a placement aiming to satisfy these conditions, a traditional product development process were executed. The articulated haulers as well as relevant literature were researched. Concepts were generated and evaluated by both the author and by employees at Volvo Construction Equipment until a final concept for the enclosure and placement were found. The enclosure were then designed in detail specifying the material, manufacturing techniques, controlled for thermodynamic circumstances, modelled in Catia V5 and controlled for vibrations. It was concluded that the enclosure should be able protect the ICCS-module after some more development and that the placement and cable routing results in a much shorter total cable length.

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