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- Nybacka, Mikael, et al.
(författare)
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Project: CASTT - Centre for Automotive Systems Technologies and Testing
- 2007
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Annan publikation (populärvet., debatt m.m.)abstract
- Through the Centre for Automotive Systems Technologies and Testing, Luleå University of Technology aims to first of all support automotive winter testing in Northern Sweden. This means to support the local automotive test entrepreneurs and through them their customers: the car manufacturers and their suppliers. To succeed in this task, the center relies on the university's areas of leading research and most importantly on the cooperation between those areas.
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- Tofique, Muhammad Waqas, 1986-, et al.
(författare)
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Development of the distributed dislocation dipole technique for the analysis of closure of complex fractures involving kinks and branches
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Annan publikation (övrigt vetenskapligt/konstnärligt)abstract
- This paper presents the development of the distributed dislocation dipole technique (DDDT) for the analysis of crack surface closure of crack cases involving kinks and branches. Crack cases in which closure occurs are analyzed by reformulating the Bueckner's principle taking the contact stresses at the contacting portions of the crack surfaces into account. Stress intensity factors corresponding to opening and sliding mode of deformation at the crack tips are computed. Three test cases involving kinked and/or branched cracks with at least one of the crack segments undergoing crack surface closure when subjected to remote tensile loading are analyzed. The results obtained from the DDDT are compared to those obtained from the Finite Element Method (FEM) analysis of the same crack cases. This comparison shows that the computation of stress intensity factors for the crack cases involving crack surface closure are less acurate compared to fully open crack cases. However, the stress intensity factors are still computed to an accuracy of within 2 percent if the Jacobi polynomial expansions of at least the sixth order are used to represent the crack surface opening and sliding displacements. Higher order Jacobi polynomials lead to increased accuracy.
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| 8. |
- Williamsson, Anna, 1981-
(författare)
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Operative managers' job-demands-resources when redesigning care processes
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Annan publikation (övrigt vetenskapligt/konstnärligt)abstract
- PurposeThe aim was to describe hospitals’ approaches to use change agents and visualmanagement tools, and examine change agents and visual management tools as job resourcesfor operative managers, during care process redesign.DesignA longitudinal three year (T0, T1, T2) mixed method design was used. Qualitativedata from semi-structured interviews was collected at five hospitals (T0, T2). Quantitativedata from questionnaires (T1, T2) was collected to examine the use and support from changeagents and visual management tools among operative managers at the hospitals. Operativemanagers’ support and associations with their working conditions were further examined inrelation to the Job Demands and Resources model. Analyses of differences between groups ofoperative managers were performed with Wilcoxon tests.FindingsChange agents as emotional job resources supported operative managers whenintroducing care process redesign. Higher change agent support was associated to positiveresults regarding burnout and organizational outcomes. Visual management tools as cognitivejob resources supported operative managers when used daily, and were associated to positiveresults regarding burnout, and organizational outcomes. Combined support from both changeagents and visual management tools was associated to beneficial organizational outcomes(collaboration between operative managers as well as between operative managers andhealthcare professionals during care process redesign, and possibilities to fulfill managerialduties) and thus were considered as important job resources for operative managers to drivechange.
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- Valizadeh, Reza, et al.
(författare)
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Improved Wells Turbine using a Concave Sectional Profile
- 2024
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Annan publikation (övrigt vetenskapligt/konstnärligt)abstract
- The current need to develop sustainable power sources has led to the development of ocean-based conversion systems. Wells turbine is a widely used converter in such systems which suffers from a lack of operational range and power production capacity under operational conditions. The profile named IFS which is concave in the post-mid-chord region, can produce significantly larger lift forces and show better separation behavior than the NACA profiles. In the present study, we tested this profile for the first time in a Wells turbine. The performance of six different blade designs with IFS and NACA profiles were evaluated and compared using a validated computational fluid dynamic model. Although the substitution of the NACA profile with the IFS profile in all cases increased the torque generated, the most efficient power generation and the largest efficient range were achieved in the design with varying thickness from the hub with a 0.15 thickness ratio reaching to the ratio of 0.2 at the tip. The operational span of this design with the IFS profile was 24.1% greater and the maximum torque generation was 71% higher than the case with the NACA profile. Therefore, the use of the IFS profile is suggested for further study and practical trials.
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