Fatigue and fracture mechanics analysis of threaded connections

This thesis aims to develop a comprehensive usable engineering design approach to the fatigue analysis of threaded connections. Although primarily concerned with the fatigue-fracture mechanics behaviour of screw threads, a broad review of stress analysis investigations in such connections is reported. Connection types, their functions and standardisation authorities are presented with the purpose of familiarising the reader with the subject and the options available to the design of threaded fasteners. Fatigue crack initiation is discussed with reference to the specific setting of a critical thread root. A crack initiation model is adapted for employment in thread root design. A novel weight function approach is developed for use in the determination of stress intensity factors for threaded connections. A generic solution is proposed valid for the fatigue crack growth from any thread root under any symmetrical stress system. Its development and discussion is examined in detail, remaining close to its proposed application. Two engineering situations where the chief structural components are comprised of threaded members are taken as case studies. The background to each situation is elaborated in detail and full-scale fatigue tests were conducted on the critical components. In all, fourteen full-scale tests under constant and variable amplitude loading are reported. The results of these are analysed and used to validate the fatigue crack initiation and propagation models. Useful observations which are helpful to understanding the fracture mechanisms operating during the fatigue of threaded connections are reported. Material and environmental considerations are examined and a survey of relevant materials and their behaviour in environments associated with threaded fasteners is presented. The merits or otherwise of some common engineering practices are discussed with regard to fatigue. A method has been developed for predicting fatigue life in large threaded connections under random loading. Experimental results have been gathered on two types of components used on certain oil rigs, tether joints and drill strings. The agreement found between prediction and experiment is appreciably better than by previous methods of analysis and also points to aspects open to further improvement

Current ecotoxicity testing needs among selected U.S. federal agencies

U.S. regulatory and research agencies use ecotoxicity test data to assess the hazards associated with substances that may be released into the environment, including but not limited to industrial chemicals, pharmaceuticals, pesticides, food additives, and color additives. These data are used to conduct hazard assessments and evaluate potential risks to aquatic life (e.g., invertebrates, fish), birds, wildlife species, or the environment. To identify opportunities for regulatory uses of non-animal replacements for ecotoxicity tests, the needs and uses for data from tests utilizing animals must first be clarified. Accordingly, the objective of this review was to identify the ecotoxicity test data relied upon by U.S. federal agencies. The standards, test guidelines, guidance documents, and/or endpoints that are used to address each of the agencies’ regulatory and research needs regarding ecotoxicity testing are described in the context of their application to decision-making. Testing and information use, needs, and/or requirements relevant to the regulatory or programmatic mandates of the agencies taking part in the Interagency Coordinating Committee on the Validation of Alternative Methods Ecotoxicology Workgroup are captured. This information will be useful for coordinating efforts to develop and implement alternative test methods to reduce, refine, or replace animal use in chemical safety evaluations

Measurement invariance of the Childhood Autism Rating Scale (CARS) across six countries

Education and Child Studie

Content and performance of the MiniMUGA genotyping array: A new tool to improve rigor and reproducibility in mouse research

The laboratory mouse is the most widely used animal model for biomedical research, due in part to its well-annotated genome, wealth of genetic resources, and the ability to precisely manipulate its genome. Despite the importance of genetics for mouse research, genetic quality control (QC) is not standardized, in part due to the lack of cost-effective, informative, and robust platforms. Genotyping arrays are standard tools for mouse research and remain an attractive alternative even in the era of high-throughput whole-genome sequencing. Here, we describe the content and performance of a new iteration of the Mouse Universal Genotyping Array (MUGA), MiniMUGA, an array-based genetic QC platform with over 11,000 probes. In addition to robust discrimination between most classical and wild-derived laboratory strains, MiniMUGA was designed to contain features not available in other platforms: (1) chromosomal sex determination, (2) discrimination between substrains from multiple commercial vendors, (3) diagnostic SNPs for popular laboratory strains, (4) detection of constructs used in genetically engineered mice, and (5) an easy-to-interpret report summarizing these results. In-depth annotation of all probes should facilitate custom analyses by individual researchers. To determine the performance of MiniMUGA, we genotyped 6899 samples from a wide variety of genetic backgrounds. The performance of MiniMUGA compares favorably with three previous iterations of the MUGA family of arrays, both in discrimination capabilities and robustness. We have generated publicly available consensus genotypes for 241 inbred strains including classical, wild-derived, and recombinant inbred lines. Here, we also report the detection of a substantial number of XO and XXY individuals across a variety of sample types, new markers that expand the utility of reduced complexity crosses to genetic backgrounds other than C57BL/6, and the robust detection of 17 genetic constructs. We provide preliminary evidence that the array can be used to identify both partial sex chromosome duplication and mosaicism, and that diagnostic SNPs can be used to determine how long inbred mice have been bred independently from the relevant main stock. We conclude that MiniMUGA is a valuable platform for genetic QC, and an important new tool to increase the rigor and reproducibility of mouse research

Surgical specimen handover from the operating theatre to laboratory-Can we improve patient safety by learning from aviation and other high-risk organisations?

Item does not contain fulltextEssential communication between healthcare staff is considered one of the key requirements for both safety and quality care when patients are handed over from one clinical area to other. This is particularly important in environments such as the operating theatre and intensive care where mistakes can be devastating. Health care has learned from other high-risk organisations (HRO) such as aviation where the use of checklists and human factors awareness has virtually eliminated human error and mistakes. To our knowledge, little has been published around ways to improve pathology specimen handover following surgery, with pathology request forms often conveying the bare minimum of information to assist the laboratory staff. Furthermore, the request form might not warn staff about potential hazards. In this article, we provide a brief summary of the factors involved in human error and introduce a novel checklist that can be readily completed at the same time as the routine pathology request form. This additional measure enhances safety, can help to reduce processing and mislabelling errors and provides essential information in a structured way assisting both laboratory staff and pathologists when handling head and neck surgical specimens

Impact of Soil Type, Biology and Temperature on the Survival of Non-Toxigenic Escherichia Coli O157

peer-reviewedThe occurrence of microbial enteropathogens in the environment can represent a serious risk to human health. The fate of enteropathogens introduced into the soil environment is dependent on a wide range of complex interacting environmental factors. While the effect of abiotic factors on enteropathogen survival has been widely examined, the interaction of enteropathogens with the soil microbial community is poorly understood. This study investigated the effect of soil biology and soil type on the survival of a non-toxigenic strain of Escherichia coli O157 under different temperature regimes. Soil microcosms of two soil types, with and without an intact microbial community, were inoculated with the enteropathogen surrogate, and survival was determined over a 64-day period, encompassing a shift from cold to ambient temperatures. In both soil types bacterial numbers decreased in soil with an intact microflora, while in the absence of an intact community E. coli populations increased. This effect was temperature specific, with E. coli populations remaining stable at low temperature, regardless of treatment. Soil type was of importance in survival at both cold and ambient temperatures. This work highlights the signifi cance of the soil microbial community in suppressing enteropathogens in soil, and of investigating die-off in a multi-factorial manner.Teagasc Walsh Fellowship Programm

Report of Technical Committee V.6 of ISSC2009: Condition Assessment of Aging Ships and Offshore Structures

ISSC Committee mandate: Concern for the assessment of the serviceability and safety of aging ships and offshore installations. This shall include reliability-based assessment of age-related structural degradation, inspection, maintenance and repair. Consideration shall be given to costbenefit and risk-based decision procedures