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admin — Wed, 17 Sep 2008 04:08:01 +0000

Different iron�chromium alloys (4, 8, 13 and 20 wt.%Cr) were nitrided in a NH3/H2 gas mixture at 580 �C for various times. The nitrided microstructure was characterized by X-ray diffraction, light microscopy and hardness measurements. Composition depth profiles of the nitrided zone were determined by electron-probe microanalysis. Residual stress�depth profiles of the nitrided specimens were measured using the (X-ray) diffraction sin2 ? method in combination with cumulative sublayer removals and correction for corresponding stress relaxations. Unusual, nonmonotonous changes of stress with depth could be related to the microstructure of the nitrided zone. A model description of the evolution of the residual stress as function of depth and nitriding time was given.

N.E. Vives D�aza?R.E. Schacherlb Email:r.schacherl@mf.mpg.de?L.F. Zagonela?E.J. Mittemeijera
[a]Max Planck Institute for Metals Research, Heisenbergstrasse 3, D-70569 Stuttgart, Germany;[b]Institute for Physical Metallurgy, University of Stuttgart, Germany ;[1] On leave from: Instituto de F�sica �Gleb Wataghin�, Universidade Estadual de Campinas, Unicamp, P.O. Box 6165 Campinas, SP, 13083-970, Brazil; Present address: CEA-DSM/DRECAM-SPCSI, CEA-Saclay, 91191, Gif-sur-Yvette, France.

admin — Wed, 17 Sep 2008 02:11:28 +0000

A trace (0.1 at.%) addition of Ge to a base Al�1.7Cu�0.3Mg alloy resulted in considerable refinement of the ?? (Al2Cu) precipitate dispersion as well as stimulating the formation of 0 0 1 lath-shaped precipitates in a fine and uniform distribution. These precipitates contain mainly Ge and Mg. The formation of the S(Al2CuMg) and ?(Al5Cu6Mg2) phases was suppressed, presumably due to the stronger interaction between Ge and Mg over Cu and Mg. Significantly, the trace addition of Ge produced an internal structure within the ?? precipitate phase with its habit plane parallel to the {1 0 1}?? planes. Our investigations reveal that this unusual internal structure is secondary precipitation within ?? precipitation of a Mg�Ge rich phase thought to be an allomorph of Mg2Ge, and this influences both the nucleation and growth of ?? precipitates. This internal structure is designated as K phase, possessing a close packed hexagonal structure (a = 0.405 nm, c = 0.607 nm) and oriented such that, (0 0 0 1)K//(1 0 1)?? and ]K//[1 0 0]??. Prolonged ageing at 200 �C led to replacement of the 0 0 1 lath-shaped precipitates through their dissolution and reprecipitation of a more stable form of Mg2Ge (face-centred cubic, Fmm, a = 0.638 nm).

S.P. RingeraEmail:s.ringer@usyd.edu.au?K.S. Prasada?G.C. Quanc
[a]Australian Key Centre for Microscopy; Microanalysis, The University of Sydney, Madsen Building F09, Sydney, NSW 2006, Australia;[b]ARC Centre of Excellence for Design in Light Metals, The University of Sydney, NSW 2006, Australia;[c]Wescast Industries Inc., Brantford, ON, N3T 5L8, Canada

Impacts of volumetric strain on CO2 sequestration in coals and enhanced CH4 recovery

admin — Wed, 17 Sep 2008 01:32:33 +0000

Sequestration of CO2 into deep, unminable coal seams is an attractive option to reduce atmospheric emissions. However, coal seams commonly have low initial permeability, and CO2 adsorption causes the coal matrix to swell, which further reduces the permeability and may result in inefficient injection. We investigate numerically the impacts of coal swelling on coal permeability and, thus, CO2 injection efficiency with constraints determined by experimental adsorption-associated volumetric strain measurements on three western Canadian coals. Our results show that injecting pure CO2 markedly reduces permeability through time to the extent that it is not a feasible sequestration technology for almost all coals. However, injection of a gas mixture of N2 and CO2 (flue gas) markedly improved CO2 injection efficiency while mildly reducing CO2 sequestration capacity. The study also suggests that different geological settings and mechanical properties of specific coal seams strongly control coal seam permeability during gas injection and, thus, viability of CO2 sequestration.

R. Marc Bustin?Xiaojun Cui?Laxmi Chikatamarla
Department of Earth and Ocean Sciences, University of British Columbia, 6339 Stores Road, Vancouver, British Columbia, Canada V6T 1Z4

Identification of microbial and thermogenic gas components from Upper Devonian black shale cores, Illinois and Michigan basins

admin — Wed, 17 Sep 2008 01:23:48 +0000

Differentiation of microbial versus thermogenic methane in coalbed and black shale accumulations can affect strategies for exploration and may influence the total gas content in a given area. Early identification of these processes from crushed core materials, even before formation fluids and produced gas samples are available, could permit a more efficient and cost-effective exploration. Total gas contents and compositional and isotopic data from New Albany Shale core materials are presented, which delineate regional occurrence of microbial, thermogenic, and mixed gas generation in the Illinois Basin. These trends are consistent with those identified from detailed prior studies of produced gas and water chemistry from the same locations. The most useful markers for microbial gas in crushed core gases are elevated CO2 contents characterized by high ?~(13)C_(CO2) values (> 5 per thousand). Core gas analyses from wells in which microbial gas is identified commonly have significantly more total gas absorbed than do core samples from wells producing gases solely of thermogenic origin. These observations are independent of variations in sample depth and organic carbon content in a given core. Thus, this integrated case study of core and produced gases in the Illinois Basin illustrates that the areas containing microbial gas, in addition to early thermogenic gas, may be more productive than pure thermogenic zones for these early to immature unconventional gas deposits.

Anna M. Martini?Lynn M. Walter?Jennifer C. Mcintosh
Department of Geology, Amherst College, Amherst, Massachusetts 01002; Department of Geological Sciences, University of Michigan, Ann Arbor, Michigan 48109; Department of Hydrology and Water Resources, University of Arizona, Tucson, Arizona 85716

Institutional rationality and practice variation: New directions in the institutional analysis of practice

admin — Wed, 17 Sep 2008 00:05:00 +0000

In this paper, I highlight how popular understandings of neoinstitutionalism as a theory of isomorphism need to be revised as institutionalists have shifted attention towards the study of organizational heterogeneity. As part of this shift, old emphases on arational mimicry and stability have been replaced with new emphases on institutional rationality and ongoing struggle and change. I discuss these new directions and the implications for the study of accounting practice. I argue that given recent efforts by institutionalists to account for actors and practice diversity, there is an important opportunity for dialogue with practice theorists, such as those drawing on Actor Network Theory, and the creation of a more comprehensive approach to the study of practice that attends to both institutional and micro-processual dynamics.

Michael Lounsbury aEmail:ml37@ualberta.ca
[a]University of Alberta School of Business; National Institute for Nanotechnology, 4-30E Business Building, Edmonton, Alberta, Canada T6G 2E7

Impacts of volumetric strain on CO2 sequestration in coals and enhanced CH4 recovery

admin — Sat, 14 Jun 2008 14:53:41 +0000

R. Marc Bustin　Xiaojun Cui　Laxmi Chikatamarla
Department of Earth and Ocean Sciences, University of British Columbia, 6339 Stores Road, Vancouver, British Columbia, Canada V6T 1Z4

Impact of federal compliance reviews of trucking companies in reducing highway truck crashes

admin — Sat, 14 Jun 2008 14:26:18 +0000

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BackgroundThe compliance review (CR) is a federal program monitoring motor carrier safety performance and regulatory compliance. This study sought to assess the impact of CRs on reviewed trucking companies in reducing truck crashes.MethodsData was from the Motor Carrier Management Information System. Study subjects were trucking companies established during 1990–1995, had at least one truck, and remained active until April 2004. Truck crash data of these companies was examined from 1996 to 2003. The crash rates in 2003 and annual percentage changes in number of crashes were computed. Analyses were stratified by company size, organization, operation classification, and safety rating.ResultsCompanies that received CRs had a higher crash rate than never-reviewed companies. Reviewed companies experienced a 39–15% reduction in number of crashes in the year the CR was performed. The reduction in crashes was observed in all reviewed companies regardless of company size, operation classification, type of organization, or safety rating. The reduction in crashes was sustained for at least 7 years after CRs.DiscussionThe study results were controlled for the year in which CRs were performed, crash trend, and CR selection bias. However, further studies, especially a randomized prospective longitudinal study, are needed to overcome the limitations that are associated with an observation study.

Guang Xiang ChenaEmail:gchen@cdc.gov
[a]National Institute for Occupational Safety and Health, Division of Safety Research, 1095 Willowdale Road, Morgantown, WV 26505-2888, USA

Truck crash　 Truck safety Compliance review Evaluation

International variation in clinical injury incidence: Exploring the performance of indicators based on health care, anatomical and outcome criteria

admin — Sat, 07 Jun 2008 22:03:37 +0000

ObjectiveTo analyse international variation in clinical injury incidence, and explore the performance of different injury indicators in cross-country comparisons.MethodsHospital discharge data of seven European countries (Austria, Denmark, Ireland, Netherlands, Norway, England and Wales) were analysed. We tested existing and newly developed indicators based on (a) health care use, (b) anatomical criteria, or (c) expected health outcome: admissions excluding day-cases (a), hospital stay 4+ (a) and 7+ days (a), (serious) long-bone fractures (b), selected radiological verifiable fractures ‘SRVFs’ (b), and indicators based on international (Global Burden of Disease) and Dutch disability weights). Assessment criteria were reduction in incidence variation and length of stay in hospital, and the association between incidence and mortality rates.ResultsIndicators based on health care use led to increased variation in incidence rates. Long bone fractures and SRVFs, and both indicators based on injuries with moderate to high disability showed similar variation in clinical incidence compared to the crude rates, smaller variation in median length of stay in hospital and a good association with mortality rates.ConclusionNo perfect or near perfect indicators of clinical injury incidence exist. For international comparisons, indicators based on disability weights, SRVFs and long bone fractures may be sensible indicators to use, in the absence of a direct measure of anatomical severity.

Suzanne PolinderaEmail:s.polinder@erasmusmc.nl　Willem Jan Meerdinga　Ronan A. Lyonsb　Juanita A. Haagsmac　Hidde Toetd　Eleni Th. Petridoue　Saakje Mulderd　Ed. F. van Beecka
[a]Department of Public Health, Erasmus MC, University Medical Centre, Ae-128, P.B. 2040, 3000 CA Rotterdam, The Netherlands;[b]Centre for Health Improvement through Research and Evaluation (CHIRAL), Swansea Medical School, University of Wales Swansea, UK;[c]Academic Medical Center Amsterdam, The Netherlands;[d]Consumer Safety Institute, Amsterdam, The Netherlands;[e]Center for Research and Prevention of Injuries (CEREPRI), Department of Hygiene and Epidemiology, University of Athens, Greece

Injury　 Indicators Clinical incidence International comparability

Identification of vehicle components associated with severe thoracic injury in motor vehicle crashes:A CIREN and NASS analysis

admin — Sat, 03 May 2008 10:59:35 +0000

IntroductionThoracic trauma secondary to motor vehicle crashes (MVC) continues to be a major cause of morbidity and mortality. Specific vehicle features may increase the risk of severe thoracic injury when striking the occupant. We sought to determine which vehicle contact points were associated with an increased risk of severe thoracic injury in MVC to focus subsequent design modifications necessary to reduce thoracic injury.MethodsThe National Automotive Sampling System (NASS) databases from 1993 to 2001 and the Crash Injury Research and Engineering Network (CIREN) databases from 1996 to 2004 were analyzed separately using univariate and multivariate logistic regression stratified by restraint use and crash direction. The risk of driver thoracic injury, defined as an abbreviated injury scale (AIS) of score ≥3, was determined as it related to specific points of contact between the vehicle and the driver.ResultsThe incidence of severe chest injury in NASS and CIREN were 5.5% and 33%, respectively. The steering wheel, door panel, armrest, and seat were identified as contact points associated with an increased risk of severe chest injury. The door panel and arm rest were consistently a frequent cause of severe injury in both the NASS and CIREN data.ConclusionsSeveral vehicle contact points, including the steering wheel, door panel, armrest and seat are associated with an increased risk of severe thoracic injury when striking the occupant. These elements need to be further investigated to determine which characteristics need to be manipulated in order to reduce thoracic trauma during a crash.

R. NirulaaEmail:raminder.nirula@utsouthwestern.edu　F.A. Pintarb
[a]Division of Trauma/Burns/Critical Care, University of Texas Southwestern Medical Center, Dallas, 5323 Harry Hines Boulevard, Dallas, TX 75390, USA;[b]Department of Neurosurgery, Medical College of Wisconsin, Milwaukee, WI 53226, USA

Thoracic　 Injury　 Vehicle　 Crash Contact Points

Implementing interpersonal psychotherapy in a psychiatry residency training program.

admin — Sun, 13 Apr 2008 03:38:15 +0000

OBJECTIVE: Interpersonal psychotherapy (IPT) for depression is a brief, well researched treatment for acute major depression. This article describes the implementation of IPT as an evidence-based treatment for depression in a psychiatry residency program. METHOD: The authors tracked the implementation process over 5 years as interpersonal psychotherapy was systematically incorporated into residency training. RESULTS: The authors outline key ingredients for and challenges to effecting change. CONCLUSIONS: Implementation of interpersonal psychotherapy in psychiatry residency training was a cornerstone for learning evidence-based treatment approaches as well as for conveying core psychotherapy concepts.

Lichtmacher J　Eisendrath SJ　Haller E