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- Lee, Christina, 1992, et al.
(författare)
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Production Across the Nordics
- 2022
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- In the uncertain and volatile market that companies are currently facing worldwide, researchers and engineers become a key link to strengthen the industry and universities in order to understand, communicate, and tackle current challenges. In the PhD course, International Production, the goal is to investigate what makes Sweden and Iceland booming industrial hubs driven by technology. Through the visits to different types of industries, such as fintech, medical, or automotive industry, we as researchers have gained a better understanding of the challenges they are currently facing. This report is a summary of our findings and observations. The participants have focused on the six challenge areas highlighted within the Produktion2030 graduate school and summarize their findings as: •Resource-efficient production: Data as a resource is becoming increasingly important for the majority of companies in the Nordics and the application of traditional resource management tools on data is a suggested area for future research. •Flexible production: To strengthen organizations by enabling production systems to be flexible to address market variations is a key challenge to consider in the manufacturing industry •Virtual production development: Digitalization level is distinct in each Nodic country with the reason that each country has its own digitalization transformation policy and different measures on digitalization level. •Humans in the production system: Humans are central in the production systems of the visited companies. Use of automation technology and AI to support humans in their work may become more common in the future. •Circular production systems and maintenance: Circular production systems require a complex approach through the whole value chain. Industry in the Nordics has started the adoption of a circularity approach. •Integrated product and production development: Integration of product and production development is a key business factor for the Nordic countries, and geographical proximity between the two departments can have a beneficial effect. We hope that this report provides more details regarding the success and current challenges of the Swedish and Icelandic enterprises.
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| 3. |
- Sun, Jielin, et al.
(författare)
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Evidence for two independent prostate cancer risk-associated loci in the HNF1B gene at 17q12
- 2008
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Ingår i: Nature Genetics. - London : Nature Publishing Group. - 1061-4036 .- 1546-1718. ; 40:10, s. 1153-1155
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- We carried out a fine-mapping study in the HNF1B gene at 17q12 in two study populations and identified a second locus associated with prostate cancer risk, 26 kb centromeric to the first known locus (rs4430796); these loci are separated by a recombination hot spot. We confirmed the association with a SNP in the second locus (rs11649743) in five additional populations, with P = 1.7 10-9 for an allelic test of the seven studies combined. The association at each SNP remained significant after adjustment for the other SNP.
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| 5. |
- Zhu, Yi, 1984-
(författare)
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Adhesion in the wheel-rail contact
- 2013
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- To attract more customers and compete with other modes of transportation, railway transport needs to ensure safety, punctuality, high comfort, and low cost; wheel–rail adhesion, i.e., the transmitted tangential force in the longitudinal direction during driving and braking, plays an important role in all these aspects. Adhesion needs to be kept at a certain level for railway operation and maintenance. However, wheel−rail contact is an open system contact. Different contaminants can present between the wheel and rail surfaces, forming a third-body layer that affects the adhesion. Prediction of wheel–rail adhesion is important for railway operations and research into vehicle dynamics; however, this prediction is difficult because of the presence of contaminants.This thesis deals with wheel–rail adhesion from a tribological perspective. The five appended papers discuss wheel–rail adhesion in terms of dry conditions, lubricated conditions, leaf contamination, iron oxides, and environmental conditions. The research methodologies used are numerical modelling, scaled laboratory experiments, and field tests. The research objective is to understand the mechanisms of the adhesion loss phenomenon. A numerical model was developed to predict wheel–rail adhesion based on real measured 3D surfaces. Computer simulation indicates that surface topography has a larger impact on lubricated than on dry contacts. Plastic deformation in asperities is found to be very important in the model. Ball-on-disc tests indicate that water can give an extremely low adhesion coefficient on smooth surfaces, possibly due to surface oxidation. Investigation of lubricated contacts at low speed indicates that oil reduces the adhesion coefficient by carrying a normal load, while adhesion loss due to water depends on the surface topography, water temperature, and surface oxidation. A field investigation indicates that leaves reduce the friction coefficient because of the chemical reaction between leaves and bulk materials. The thickness of the surface oxide layer was found to be an essential factor determining adhesion reduction. Pin-on-disc experiments found a transition in the friction coefficient with regard to the relative humidity, due to a trade-off between the water molecule film and the hematite on the surface.
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- Zhu, Yi, 1984-
(författare)
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Adhesion in the wheel-rail contact under contaminated conditions
- 2011
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Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Railway vehicles require a certain level of adhesion between wheel and rail to operate efficiently, reliably, and economically. Different levels of adhesion are needed depending on the vehicle running conditions. In the wheel tread–railhead contact, the dominant problem is low adhesion, as low adhesion on the railhead negatively affects railway operation: on one hand, the vehicle will lose traction resulting in delay when driving on low-adhesion tracks; on the other hand, low adhesion during deceleration will extend the braking distance, which is a safety issue. This thesis examines the influence of several contaminants, i.e., water, oil, and leaves, on the adhesion in the wheel tread–railhead contact. This study will improve our knowledge of the low-adhesion mechanism and of how various contaminants influence adhesion. The thesis consists of a summary overview of the topic and three appended papers (A–C). Papers A and B focus mainly on water and oil contamination examined using two methods, numerical simulation and lab testing. In paper A, real measured wheel and rail surfaces, low- and high-roughness surfaces, along with generated smooth surfaces are used as input to the numerical model for predicting the adhesion coefficient. Water-lubricated, oil-lubricated, and dry contacts are simulated in the model. In the research reported in paper B, scaled testing using a mini traction machine (MTM) was carried out to simulate the wheel–rail contact under lubricated conditions. Two types of disc surfaces of different roughnesses were run at different contact pressures and temperatures. A stylus machine and atomic force microscopy (AFM) were used to measure the surface topography. A study of leaf contamination on the railhead surface, based on field testing, is presented in paper C. Railhead surface samples were cut and the friction coefficient was measured on five occasions over the course of a year. Electron spectroscopy for chemical analysis (ESCA) and glow discharge optical emission spectrometry (GD-OES) were used to detect the chemical composition of the leaf-contamination layer on the railhead surface. The main conclusion of the thesis is that different contaminants reduce the adhesion coefficient in different ways. Oil reduces the adhesion coefficient by carrying the normal force due to its high viscosity. Water can reduce the adhesion coefficient to different degrees depending on the surface topography and water temperature. The mixture of an oxide layer and water contamination may have an essential impact. A leaf-formed blackish layer causes low adhesion by means of a chemical reaction between the leaves and bulk material. The thickness of the friction-reducing oxide layer predicts the friction coefficient and the extent of leaf contamination.
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