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Estimation of Fatigue Life of Laser Welded AISI304 Stainless Steel T-Joint Based on Experiments and Recommendations in Design Codes

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World Journal of Mechanics 2013年第3期3卷 178-183页

作者： S?ren Heide Lambertsen Lars Damkilde anders Schmidt kristensen Ronnie Refstrup Pedersen Division of Structures and Materials Aalborg University EsbjergEsbjergDenmark

In this paper the fatigue behavior of laser welded T-joints of stainless steel AISI304 is investigated experimentally. In the fatigue experiments 36 specimens with a sheet thickness of 1 mm are exposed to one-dimensional cyclic loading. Three different types of specimens are adopted. Three groups of specimens are used, two of these are non-welded and the third is welded with a transverse welding (T-Joint). The 13 laser welded specimens are cut out with a milling cutter. The non-welded specimens are divided in 13 specimens cut out with a milling cutter and 10 specimens cut out by a plasma cutter. The non-welded specimens are used to study the influence of heat and surface effects on the fatigue life. The fatigue life from the experiments is compared to fatigue life calculated from the guidelines in the standards DNV-RP-C203 and EUROCODE 3 EN-1993-1-9. Insignificant differences in fatigue life of the welded and non-welded specimens are observed in the experiments and the largest difference is found in the High Cycle Fatigue (HCF) area. The specimens show a lower fatigue life compared to DNV-RP-C203 and EUROCODE 3 EN-1993-1-9 when the specimens are exposed to less than 4.0 1E06 cycles. Therefore, we conclude that the fatigue life assessment according to the mentioned standards is not satisfactory and reliable.

关键词： AISI304 Laser Welding Austenite Martensite

Surgical apgar score predicts early complication in transfemoral amputees:Retrospective study of 170 major amputations

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World Journal of Orthopedics 2016年第12期7卷 832-838页

作者： Christian Wied Nicolai B Foss Morten T kristensen Gitte Holm Thomas Kallemose anders Troelsen Department of Orthopedic Surgery Copenhagen University Hospital Hvidovre Department of Anesthesiology and Intensive Care Copenhagen University Hospital Hvidovre Physical Medicine and Rehabilitation Research-Copenhagen Department of Physical TherapyCopenhagen University Hospital Hvidovre Clinical Research Centre Copenhagen University Hospital Hvidovre

AIM To assess whether the surgical apgar score(SAS) is a prognostic tool capable of identifying patients at risk of major complications following lower extremity amputations *** This was a single-center,retrospective observational cohort study conducted between January 2013 and April 2015. All patients who had either a primary transtibial amputation(TTA) or transfemoral amputation(TFA) conducted at our institution during the study period were assessed for inclusion. All TTA patients underwent a standardized one-stage operative procedure(ad modum Persson amputation) performed approximately 10 cm below the knee joint. All TTA procedures were performedwith sagittal flaps. TFA procedures were performed in one stage with amputation approximately 10 cm above the knee joint,performed with anterior/posterior flaps. Trained residents or senior consultants performed the surgical procedures. The SAS is based on intraoperative heart rate,blood pressure and blood loss. Intraoperative parameters of interest were collected by revising electronic health records. The first author of this study calculated the SAS. Data regarding major complications were not revealed to the author until after the calculation of SAS. The SAS results were arranged into four groups(SAS 0-4,SAS 5-6,SAS 7-8 and SAS 9-10). The cohort was then divided into two groups representing low-risk(SAS ≥ 7) and highrisk patients(SAS < 7) using a previously established threshold. The outcome of interest was the occurrence of major complications and death within 30-d of *** A logistic regression model with SAS 9-10 as a reference showed a significant linear association between lower SAS and more postoperative complications [all patients: OR = 2.00(1.33-3.03),P = 0.001]. This effect was pronounced for TFA [OR = 2.61(1.52-4.47),P < 0.001]. A significant increase was observed for the high-risk group compared to the low-risk group for all patients [OR = 2.80(1.40-5.61),P = 0.004] and for the TFA sub-

关键词： Surgical apgar score Mortality Transfemoral amputation Post-operative complication Lower extremity amputation

Tourniquets do not increase the total blood loss or reamputation risk in transtibial amputations

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World Journal of Orthopedics 2017年第1期8卷 62-67页

作者： Christian Wied Peter T Tengberg Gitte Holm Thomas Kallemose Nicolai B Foss anders Troelsen Morten T kristensen Depart-ment of Orthopedic Surgery Copenhagen University Hospital Hvidovre Clinical Research Centre Copenhagen University Hospital Hvidovre Department of Anesthesiology and Intensive Care Copenhagen University Hospital Hvidovre Physical Medicine and Rehabilita-tion Research--Copenhagen Department of Physical TherapyCopenhagen University Hospital Hvidovre

AIM To investigate the total blood loss(TBL) and the safety with respect to the re-amputation rate after transtibial amputation(TTA) conducted with and without a tourniquet. METHODS The study was a single-centre retrospective cohort study of patients with a primary TTA admitted between January 2013 and April 2015. All patients with a primary TTA were assessed for inclusion if the amputation was performed because of arteriosclerosis or diabetic complications. All patients underwent a standardized TTA procedure that was performed approximately 10 cm below the knee joint and performed with sagittalflaps. The pneumatic tourniquet, when used, was inflated around the femur to a pressure of 100 mmH g above the systolic blood pressure. The number of blood transfusions within the first four postoperative days was recorded. The intraoperative blood loss(OBL), which is defined as the volume of blood lost during surgery, was determined from the suction volume and by the weight difference of the surgical dressings. The trigger for a blood transfusion was set at a decrease in the Hgb level < 9.67 g/dL(6 mmol/L). Transfusions were performed with pooled red blood cells containing 245 m L per portion, which equals 55 g/L of haemoglobin. The TBL during the first four postoperative days was calculated based on the haemoglobin level and the estimated blood volume. The re-amputation rate was evaluated within 30 d. RESULTS Seventy-four out of 86 consecutive patients who underwent TTA within the two-year study period were included in the analysis. Of these, 38 were operated on using a tourniquet and 36 were operated on without using a tourniquet. There were no significant preoperative differences between the groups. The patients in both groups had a postoperative decrease in their Hgb level compared with preoperative baseline values. The patients operated on using a tourniquet received approximately three millilitres less blood transfusion per kilogram body weight compared with patients o

关键词： Total blood loss Intraoperative blood loss Transtibial amputation Lower extremity amputation Pneumatic tourniquet Re-amputation

Identification and characterization of the capsule biosynthetic locus of Gallibacterium anatis biovar haemolytica

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Identification and characterization of the capsule biosynthe...

北欧岩高兰(Empetrum)生态系统:功能及其对环境变化的敏感性

The 15th World Veterinary Poultry Congress

作者： anders M Bojesen Edgardo V Soriano Bodil M kristensen Department of Veterinary Pathobiology Faculty of Life SciencesUniversity of CopenhagenDK-1870 Frederiksberg CDenmark. Centro de Investigaci y Estudios Avanzados en Salud Animal Facultad de Medicina Veterinaria y ZootecniaUniversidad Aut oma del Estado de MexicoToluca50000Mexico Department of Veterinary Pathobiology Faculty of Life SciencesUniversity of CopenhagenDK-1870 Frederiksberg CDenmark.

＜正＞The aim of this study was to identify and characterize the genetic elements responsible for capsule biosyn- thesis in *** is a common inhabitant of the upper respiratory and lower genital tract of poultry but ha...

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AMBIO－人类环境杂志 2000年第2期29卷 90-97页

作者： Knud Tybirk Marie-Charlotte Nilsson anders Michelsen Hanne Lakkenborg kristensen Anna shevtsova Morten Tune Strandberg Marianne Johansson Knud Erik Nielsen Torben Riis-Nielsen Beate Strandberg Ib Johansen 萨仁 NERI Dept.of Landscape Ecology Grenvej 14 DK-8410 Rnde Denraark Forest Vegetation Ecology SLU SE-90183 Ume Sweden Plant Ecology Φ.Farimagasgade 2DDK-1353 Copenhagen K Denmark of Forest Ecology Forest and Landscape Research Institute Hrsholm Kongevej 29 DK-2970 Hrshoim Denmark Biology University of Turku FIN-20014 Turku Finland Terrestrial Ecology NERI Vejlsvej 25 DK-8600 SilkeborgDenmark of Mycology Botanical Institute University of Copenhagen .Farimagasgade 2D DK-1353 Copenhagen K Denmark Forest Ecology Forest and Landscape Research Institute Hrsholm Kongevej 29 DK-2970 Hrsholm Denmark Plant Ecology University of Copenhagen .Farimagasgade 2D DK-1353 Copenhagen K Denmark

本文回顾了关于北欧地区岩高兰(Empetrum nigrum ***和***)生态系统的知识。因为岩高兰叶片及其枯枝落叶含有丰富的酚,分解缓慢,随着有机质表土层的形成,养分存储于有机养分库中,主要由具有石南状根的植物所吸收利用。黑果岩高兰(Empetr... 详细信息

本文回顾了关于北欧地区岩高兰(Empetrum nigrum ***和***)生态系统的知识。因为岩高兰叶片及其枯枝落叶含有丰富的酚,分解缓慢,随着有机质表土层的形成,养分存储于有机养分库中,主要由具有石南状根的植物所吸收利用。黑果岩高兰(Empetrum nigrum)亚种Hermaphroditum是强有力的养分竞争者,并且在演替后期能战胜多数植物。这是化学干扰(他感作用)和资源竞争所致。岩高兰作为一种有机体耐大气污染,在适林海岸石南丛生地,由于大气中大量氮的沉积其生长活力甚至有所增加,但是它对机械干扰及火烧非常敏感。然而,有迹象表明,空气中无机气氮的输入可对岩高兰占优势时所形成的封闭式营养循环产生干扰。

关键词：北欧岩高兰生态系统功能环境变化敏感性