• Title/Summary/Keyword: Chalmers

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Biomechanical investigation of arm position on deforming muscular forces in proximal humerus fractures

  • Christen E. Chalmers;David J. Wright;Nilay A. Patel;Hunter Hitchens;Michelle McGarry;Thay Q. Lee;John A. Scolaro
    • Clinics in Shoulder and Elbow
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    • v.25 no.4
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    • pp.282-287
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    • 2022
  • Background: Muscular forces drive proximal humeral fracture deformity, yet it is unknown if arm position can help mitigate such forces. Our hypothesis was that glenohumeral abduction and humeral internal rotation decrease the pull of the supraspinatus and subscapularis muscles, minimizing varus fracture deformity. Methods: A medial wedge osteotomy was performed in eight cadaveric shoulders to simulate a two-part fracture. The specimens were tested on a custom shoulder testing system. Humeral head varus was measured following physiologic muscle loading at neutral and 20° humeral internal rotation at both 0° and 20° glenohumeral abduction. Results: There was a significant decrease in varus deformity caused by the subscapularis (p<0.05) at 20° abduction. Significantly increasing humeral internal rotation decreased varus deformity caused by the subscapularis (p<0.05) at both abduction angles and that caused by the supraspinatus (p<0.05) and infraspinatus (p<0.05) at 0° abduction only. Conclusions: Postoperative shoulder abduction and internal rotation can be protective against varus failure following proximal humeral fracture fixation as these positions decrease tension on the supraspinatus and subscapularis muscles. Use of a resting sling that places the shoulder in this position should be considered.

Evaluation of Common Activity and Life in Swedish Cohousing Units

  • Choi, Jung-Shin;Paulsson, Jan
    • International Journal of Human Ecology
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    • v.12 no.2
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    • pp.133-146
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    • 2011
  • This study evaluates common activity and quality of life in Swedish cohousing units to examine whether Swedish cohousing functions properly or not. A questionnaire survey was fulfilled during the autumn of 2010 in G$\ddot{o}$teborg Sweden. The subjects of study were 12 of 44 cohousing units in Sweden that included 4 of the +40 cohousing and 8 of the mixed-age cohousing. A total of 242 of 353 distributed questionnaires were collected (68.6%) and analyzed by SPSS statistical program. The findings are as follow: 1) General characteristics of the respondents are that they are mostly healthy, evenly aged from age 50s to 70s and highly educated with significant proportions of academics and civil workers. There are more females than males and more singles than cohabitants. 2) The most frequent and preferred common activity is a common meal followed by a coffee meeting. A common dinner, the 'hub of living together' is held almost every day or at least a few times a week. A common meal is considered one of the most important activities because of practical and social advantages in that residents can save time and cooking costs as well as engage in social contact. Referring to evaluation of frequency and content of common activity, more than a half of the respondents prefer the current situation. 3) All of the variables (except health conditions and education level) affect participation in common activity with statistical significance. 4) Most of the respondents indicate a high level of life satisfaction and are willing to recommend others move to cohousing. They agree that there is more mutual support among residents in cohousing units than in a conventional community. In conclusion, Swedish cohousing units function successfully as they have pursued intentional community ideology and most of the residents are proud of their current living situations.

MOLECULAR GAS AND RADIO JET INTERACTION: A CASE STUDY OF THE SEYFERT 2 AGN M51

  • MATSUSHITA, SATOKI;TRUNG, DINH-V;BOONE, FRDERIC;KRIPS, MELANIE;LIM, JEREMY;MULLER, SEBASTIEN
    • Publications of The Korean Astronomical Society
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    • v.30 no.2
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    • pp.439-442
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    • 2015
  • We observed multiple CO transition lines and the HCN(1-0) line at ~ 1" (~ 34 pc) or higher resolution toward the Seyfert 2 nucleus of M51 using the IRAM Plateau de Bure Interferometer (PdBI) and the Submillimeter Array (SMA). All the images show very similar overall molecular gas distribution; there are two discrete clouds at the eastern and western sides of the nucleus, and the western cloud exhibits an elongated distribution and velocity gradient along the radio jet. In addition, high HCN(1-0)/CO(1-0) brightness temperature ratios of about unity have been observed, especially along the radio jet, similar to those observed in shocked molecular gas in our Galaxy. This strongly indicates that the molecular gas along the jet is shocked, that the radio jet and the molecular gas are interacting, and the jet is entraining both diffuse (CO) and dense (HCN) molecular gas outwards from the circumnuclear region. This is the first clear imaging of the outflowing molecular gas entrained by the AGN jet, and showing the detailed physical status of outflowing molecular gas. Since a relatively high HCN(1-0)/CO(1-0) ratio has been observed in the high velocity wing of ultraluminous infrared galaxies, it can also be explained by a similar mechanism to those we describe here.

Investigation of aerodynamic behaviour of a high-speed train on different railway infrastructure scenarios under crosswind

  • Jiqiang, Niu;Yingchao, Zhang;Zhengwei, Chen;Rui, Li;Huadong, Yao
    • Wind and Structures
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    • v.35 no.6
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    • pp.405-418
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    • 2022
  • The aerodynamic behaviour of a CRH high-speed train under three infrastructure scenarios (flat ground, embankment, and viaduct) in the presence of a crosswind was simulated using a 1/8th scaled train model with three cars and the IDDES framework. The time-averaged and instantaneous flow field around the model were examined. The employed numerical algorithm was verified through a wind tunnel test, and the grid and timestep resolution analyses were conducted to ensure the reliability of the data. It was noted that the flow around the rail line was different under different infrastructure scenarios, especially in the case of the embankment, which degraded the aerodynamic performance of the train under the crosswind. The flow around the train on the flat ground and viaduct was different, although the aerodynamic performance of the train was similar in both cases. Moreover, the viaduct accidents were noted to have the most critical consequences, thereby requiring the most attention. The aerodynamic performance of the train on the windward track of the embankment under the crosswind was worse than that of the train on the leeward track. But for the other two infrastructure scenarios, the aerodynamic performance of the train on the windward track is relatively dangerous, which is mainly caused by the head car. These observations suggest that the aerodynamic behaviour of the train on an embankment under a crosswind must be carefully considered and that certain wind protection measures must be adopted around rail lines in windy areas.

A Devolatilization Model of Woody Biomass Particle in a Fluidized Bed Reactor (유동층 반응기에서의 목질계 바이오매스 입자의 탈휘발 예측 모델)

  • Kim, Kwang-Su;Leckner, Bo;Lee, Jeong-Woo;Lee, Uen-Do;Choi, Young-Tai
    • Korean Chemical Engineering Research
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    • v.50 no.5
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    • pp.850-859
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    • 2012
  • Devolatilization is an important mechanism in the gasification and pyrolysis of woody biomass, and has to be accordingly considered in designing a gasifier. In order to describe the devolatilization process of wood particle, there have been proposed a number of empirical correlations based on experimental data. However, the correlations are limited to apply for various reaction conditions due to the complex nature of wood devolatilization. In this study, a simple model was developed for predicting the devolatilization of a wood particle in a fluidized bed reactor. The model considered the drying, shrinkage and heat generation of intra-particle for a spherical biomass. The influence of various parameters such as size, initial moisture content, heat transfer coefficient, kinetic model and temperature, was investigated. The devolatilization time linearly increased with increasing initial moisture content and size of a wood particle, whereas decreases with reaction temperature. There is no significant change of results when the external heat transfer coefficient is over 300 $W/m^2K$, and smaller particles are more sensitive to the outer heat transfer coefficient. Predicted results from the model show a similar tendency with the experimental data from literatures within a deviation of 10%.