• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 35
  • 8
  • 5
  • 4
  • 3
  • 3
  • 2
  • 2
  • 1
  • 1
  • Tagged with
  • 72
  • 10
  • 7
  • 6
  • 6
  • 6
  • 6
  • 6
  • 6
  • 5
  • 5
  • 5
  • 5
  • 5
  • 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.
71

Sänka bundet kapital i ett mellanlager : -En studie utförd i syfte att finna orsaken till varför lager bildas för att därefter presentera en eller flera åtgärder som bidrar till minskat bundet kapital i lager / Decrease tied up capital in stock : -A case study conducted in purpose to find root causes to how stocks is formed and thereafter introduce one or many arrangements with intention to reduce tied up kapital in stock

Svensson, Gustav, Nilsson, Jesper January 2018 (has links)
Purpose – Globalization affects all producing companies with increased complexity in production, stock management and never ending customer demands. The customers of today have a greater range of suppliers than before with even more products to choose from which puts the customer in a strong position. One of many important subjects that companies need to work with to keep their competitiveness strong against each other is to work with continuous improvements in production- and inventory management. This study therefore reviews tied up capital in stock and suggest adequate procedures, which could be applied to decrease the tied up capital.   Method –In order to fulfil the purpose a case study is conducted. Two central research questions are chosen for the study to investigate in a case company. The data collected contains of secondary data, observations and interviews. To accomplish the purpose a theoretical framework has been put together.   Findings – Reducing variations in production and re-designing of the daily production plan is presented as the two procedures with the purpose to achieve a decrease in tied up capital for stock kept units. The study describes these two procedures in general in order to make the solution applicable into various manufacturing company. Further the study claims that gaining flow efficiency should be prioritized instead of resource efficiency, which could be accomplished by the two procedures.    Implications – The study contributes to verifying production theories, foremost about variations in production, Lean manufacturing and the technique of Lead-time mapping.   Limitations – In order to apply the procedures with precision and efficiency some further data and extended studies needs to be performed. This study is performed in a generalizing point of view, which may influence the results.  The study does not capture every aspect of affecting circumstances that might be needed for a successful implementation of suggested procedures.   Keywords – Tied up capital, Lead-time, Lean, Lead-time mapping, Variations, Flow efficiency, Postponement, Just-in-Time, Make-to-stock and Make-to-order. / Syfte – Globaliseringen har gjort att kunden har ett högre utbud att välja mellan och kan därmed ställa högre krav på tillverkande verksamheter. För att fortsatt vara konkurrenskraftig måste verksamheter ständigt utveckla den interna produktion- och materialstyrningen. Studiens ämnar därmed undersöka orsaken till uppkomsten av bundet kapital i lager samt finna potentiella åtgärder som kan vidtas inom verksamheten för att på ett hållbart sätt minska bundet kapital i lager.   Metod – För att uppfylla studiens syfte tillämpas fallstudie. Studien utgår från två frågeställningar som besvaras med hjälp av data från ett fallföretag. Data som samlas är hämtad från sekundärdata, observationer och intervjuer. Därtill har ett teoretiskt ramverk upprättats vilken studien utgår ifrån.   Resultat – Minska variationer samt utförande av en mer detaljerad planering presenteras som studiens två åtgärdsförslag för att minska bundet kapital i lager. Studien beskriver övergripande potentiella tillvägagångssätt för att åstadkomma förslagen. Studien konstaterar att flödeseffektivitet med fördel bör prioriteras framför resurseffektiviteten i verksamheten, vilket uppfylls med hjälp av åtgärdsförslagen.   Implikationer – Studien bidrar inte till nya teorier men verifierar befintliga teorier främst kring variationer i tillverkning, Lean och ledtidskartläggning.   Begränsningar – För att åtgärdsförslagen i studiens resultat ska kunna tillämpas krävs ytterligare data och fördjupade studier för att garantera att samtliga aspekter ska fångas in samt att orsak och påverkan av åtgärderna ska kunna kartläggas. Studien bygger på generaliserande antaganden vilket ger ett generaliserat resultat.   Nyckelord – Lean, Ledtid, Ledtidskartläggning, Variationer, Flödeseffektivitet, Senareläggning, Just-in-Time, Make-to-order och Bundet kapital.
72

MECHANICAL BEHAVIORS OF BIOMATERIALS OVER A WIDE RANGE OF LOADING RATES

Xuedong Zhai (8102429) 10 December 2019 (has links)
<div>The mechanical behaviors of different kinds of biological tissues, including muscle tissues, cortical bones, cancellous bones and skulls, were studied under various loading conditions to investigate their strain-rate sensitivities and loading-direction dependencies. Specifically, the compressive mechanical behaviors of porcine muscle were studied at quasi-static (<1/s) and intermediate (1/s─10^2/s) strain rates. Both the compressive and tensile mechanical behaviors of human muscle were investigated at quasi-static and intermediate strain rates. The effect of strain-rate and loading-direction on the compressive mechanical behaviors of human frontal skulls, with its entire sandwich structure intact, were also studied at quasi-static, intermediate and high (10^2/s─10^3/s) strain rates. The fracture behaviors of porcine cortical bone and cancellous bone were investigated at both quasi-static (0.01mm/s) and dynamic (~6.1 m/s) loading rates, with the entire failure process visualized, in real-time, using the phase contrast imaging technique. Research effort was also focused on studying the dynamic fracture behaviors, in terms of fracture initiation toughness and crack-growth resistance curve (R-curve), of porcine cortical bone in three loading directions: in-plane transverse, out-of-plane transverse and in-plane longitudinal. A hydraulic material testing system (MTS) was used to load all the biological tissues at quasi-static and intermediate loading rates. Experiments at high loading rates were performed on regular or modified Kolsky bars. Tomography of bone specimens was also performed to help understand their microstructures and obtain the basic material properties before mechanical characterizations. Experimental results found that both porcine muscle and human muscle exhibited non-linear and strain-rate dependent mechanical behaviors in the range from quasi-static (10^(-2)/s─1/s) to intermediate (1/s─10^2/s) loading rates. The porcine muscle showed no significant difference in the stress-strain curve between the along-fiber and transverse-to-fiber orientation, while it was found the human muscle was stiffer and stronger along fiber direction in tension than transverse-to fiber direction in compression. The human frontal skulls exhibited a highly loading-direction dependent mechanical behavior: higher ultimate strength, with an increasing ratio of 2, and higher elastic modulus, with an increasing ratio of 3, were found in tangential loading direction when compared with those in the radial direction. A transition from quasi-ductile to brittle compressive mechanical behaviors of human frontal skulls was also observed as loading rate increased from quasi-static to dynamic, as the elastic modulus was increased by factors of 4 and 2.5 in the radial and tangential loading directions, respectively. Experimental results also suggested that the strength in the radial direction was mainly depended on the diploë porosity while the diploë layer ratio played the predominant role in the tangential direction. For the fracture behaviors of bones, straight-through crack paths were observed in both the in-plane longitudinal cortical bone specimens and cancellous bone specimens, while the cracks were highly tortuous in the in-plane transverse cortical bone specimens. Although the extent of toughening mechanisms at dynamic loading rate was comparatively diminished, crack deflections and twists at osteon cement lines were still observed in the transversely oriented cortical bone specimens at not only quasi-static loading rate but also dynamic loading rate. The locations of fracture initiations were found statistical independent on the bone type, while the propagation direction of incipient crack was significantly dependent on the loading direction in cortical bone and largely varied among different types of bones (cortical bone and cancellous bone). In addition, the crack propagation velocities were dependent on crack extension over the entire crack path for all the three loading directions while the initial velocity for in-plane direction was lower than the other two directions. Both the cortical bone and cancellous bone exhibited higher fracture initiation toughness and steeper R-curves at the quasi-static loading rate than the dynamic loading rate. For cortical bone at a dynamic loading rate (5.4 m/s), the R-curves were steepest, and the crack surfaces were most tortuous in the in-plane transverse direction while highly smooth crack paths and slowly growing R-curves were found in the in-plane longitudinal direction, suggesting an overall transition from brittle to ductile-like fracture behaviors as the osteon orientation varies from in-plane longitudinal to out-of-plane transverse, and to in-plane transverse eventually.</div>

Page generated in 0.0203 seconds