1,289 research outputs found

    Research of the power plant operational states with block structure

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    In this article the research technique block structure power plant operational states is offered. As an example the operating power plant of OOO Siberian Generation Company with block structure of turbogenerators connection is considered. The choice of the operating power plant has allowed to receive to carry out the analysis real long and emergency states. The offered technique of states identification and the analysis can be used for power plant of other structure after the corresponding correction

    A root-cause analysis of maternal deaths in Botswana: towards developing a culture of patient safety and quality improvement

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    BACKGROUND: In 2007, 95% of women in Botswana delivered in health facilities with 73% attending at least 4 antenatal care visits. HIV-prevalence in pregnant women was 28.7%. The maternal mortality ratio in 2010 was 163 deaths per 100 000 live births versus the government target of 130 for that year, indicating that the Millennium Development Goal 5 was unlikely to be met. A root-cause analysis was carried out with the aim of determining the underlying causes of maternal deaths reported in 2010, to categorise contributory factors and to prioritise appropriate interventions based on the identified causes, to prevent further deaths. METHODS: Case-notes for maternal deaths were reviewed by a panel of five clinicians, initially independently then discussed together to achieve consensus on assigning contributory factors, cause of death and whether each death was avoidable or not at presentation to hospital. Factors contributing to maternal deaths were categorised into organisational/management, personnel, technology/equipment/supplies, environment and barriers to accessing healthcare. RESULTS: Fifty-six case notes were available for review from 82 deaths notified in 2010, with 0–4 contributory factors in 19 deaths, 5–9 in 27deaths and 9–14 in nine. The cause of death in one case was not ascertainable since the notes were incomplete. The high number of contributory factors demonstrates poor quality of care even where deaths were not avoidable: 14/23 (61%) of direct deaths were considered avoidable compared to 12/32 (38%) indirect deaths. Highest ranking categories were: failure to recognise seriousness of patients’ condition (71% of cases); lack of knowledge (67%); failure to follow recommended practice (53%); lack of or failure to implement policies, protocols and guidelines (44%); and poor organisational arrangements (35%). Half the deaths had some barrier to accessing health services. CONCLUSIONS: Root-cause analysis demonstrates the interactions between patients, health professionals and health system in generating adverse outcomes for patients. The lessons provided indicate where training of undergraduate and postgraduate medical, midwifery and nursing students need to be intensified, with emphasis on evidence-based practice and adherence to protocols. Action plans and interventions aimed at changing the circumstances that led to maternal deaths can be implemented and re-evaluated

    Characterization and Simulation of High-Speed-Deformation-Processes

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    The combination of the processes deep drawing and electromagnetic pulse forming is a promising way to cope with the ever higher complexity of new sheet metal designs. A cooperation between the Institute of Materials Science (IW) of the Leibniz Universität Hannover and the Institute of Applied Mechanics (IFAM) of the RWTH Aachen is investigating these processes both experimental and in simulation. Aim is the characterization of the combined process. Therefore the material properties of the investigated aluminum alloy EN AW 6082 T6 have to be determined quasi-static as well as at high speed. These properties are then used as a basic for the simulations. Anisotropic behaviors as well as dynamic hardening effects are investigated in the quasi-static state. Several experiments for analyzing "Bauschinger" respectively "Ratcheting effects" have been conducted resulting in a new measuring set-up for thin sheets. For the determination of high speed forming limit diagrams a novel testing device on the basis of the Nakajima-test has been developed allowing for strain rates of approximately 10^3 s^-1. Both testing methods are described in this paper; the results are then used to adapt the simulation models for the combined processes. The high speed deformation process is simulated by means of finite elements using a material model developed at the IFAM. The finite strain constitutive model combines nonlinear kinematic and isotropic hardening and is derived in a thermodynamic setting. It is based on the multiplicative split of the deformation gradient in the context of hyperelasticity. The kinematic hardening component represents a continuum extension of the classical rheological model of Armstrong-Frederick kinematic hardening which is widely adopted as capable of representing the above metal hardening effects. To prevent locking of the simulated thin sheets a new eight-node solid-shell finite element based on reduced integration with hourglass stabilization developed at IFAM has been used. With these features it was possible to simulate the Bauschinger effect obtained by the previous experiments

    Longitudinal study of the effects of teat condition on the risk of new intramammary infections in dairy cows

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    Machine milking–induced alterations of teat tissue may impair local defense mechanisms and increase the risk of new intramammary infections. The objective of the current study was to assess the influence of short-term and long-term alterations of teat tissue and infectious status of the udder quarter on the risk of naturally occurring new intramammary infections, inflammatory responses, and mastitis. Short-term and long-term changes in teat condition of right udder quarters of 135 cows of a commercial dairy farm in Saxony-Anhalt, Germany, were recorded monthly for 10 mo using simple classification schemes. Quarter milk samples were collected from all examined quarters at each farm visit. Bacteriological culture results and somatic cell counts of quarter milk samples were used to determine new inflammatory responses (increase from ≤100,000 cells/mL to >100,000 cells/mL between 2 samples), new infections (detection of a pathogen from a quarter that was free of the same pathogen at the preceding sampling), and new mastitis (combination of new inflammatory response and new infection). Separate Poisson mixed models for new inflammatory responses, new infections, and new mastitis caused by specific pathogens or groups of pathogens (contagious, environmental, major, minor, or any) were used to estimate risk ratios and 95% confidence intervals. Data preparation and parameter estimation were performed using the open source statistical analysis software R. We observed no effect of any variable describing teat condition on the risk of new intramammary infections, inflammatory responses, or mastitis. Intramammary infections of the same udder quarter in the preceding month did not affect risk either

    A Miniaturized Multi Sensor Array for Balloon-Borne Air Measurements, Phase I

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    Weber State University’s High-Altitude Ballooning team, HARBOR, has seen an opportunity for cooperative research among the many individual balloon teams based in North America. The Great American Solar Eclipse brought these teams into the spotlight as dozens of ballooning groups worked together to image the eclipse. Leveraging this collection of balloon teams to create a large-scale data set could make some valuable discoveries and give us a better understanding of the atmospheric dynamics that take place in the stratosphere. Our team has decided to facilitate the creation of such a data set by designing an atmospheric data collection tool, the mini-Multi Sensor Array, that can be flown by teams all over the nation, and potentially the world. Our goal is to create an inexpensive, lightweight, easy to assemble device which will measure gas concentrations, particulate matter, atmospheric turbulence, and meteorological parameters such as temperature, pressure, and humidity. We will also add features such as long distance telemetry, which will facilitate recovery of these payloads. Having a redundant, lightweight tracking device will increase the number of flight teams that are making a regular effort to fly our mini-MSA with their payload

    Напряженное состояние призабойной части массива при проведении горных выработок с конической формой забоя

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    У рамках механіки пружно-деформованого тіла розроблена методика та розв’язана задача про напружений стан гірського масиву навколо горизонтальної циліндричної виробки. Чисельними дослідженнями виявлено значну концентрацію розтягуючих напружень у зоні ведення гірничих робіт.A method of stress state of a rock massif near the horizontal cylindrical working is developed, and a problem of mechanics of elastically deformed bodies is solved. A considerable concentration of tensile stresses in the mining working zone is revealed by numerical calculations

    A systematic review of the relationship between subchondral bone features, pain and structural pathology in peripheral joint osteoarthritis

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    Introduction: Bone is an integral part of the osteoarthritis (OA) process. We conducted a systematic literature review in order to understand the relationship between non-conventional radiographic imaging of subchondral bone, pain, structural pathology and joint replacement in peripheral joint OA. Methods: A search of the Medline, EMBASE and Cochrane library databases was performed for original articles reporting association between non-conventional radiographic imaging-assessed subchondral bone pathologies and joint replacement, pain or structural progression in knee, hip, hand, ankle and foot OA. Each association was qualitatively characterised by a synthesis of the data from each analysis based upon study design, adequacy of covariate adjustment and quality scoring. Results: In total 2456 abstracts were screened and 139 papers were included (70 cross-sectional, 71 longitudinal analyses; 116 knee, 15 hip, six hand, two ankle and involved 113 MRI, eight DXA, four CT, eight scintigraphic and eight 2D shape analyses). BMLs, osteophytes and bone shape were independently associated with structural progression or joint replacement. BMLs and bone shape were independently associated with longitudinal change in pain and incident frequent knee pain respectively. Conclusion: Subchondral bone features have independent associations with structural progression, pain and joint replacement in peripheral OA in the hip and hand but especially in the knee. For peripheral OA sites other than the knee, there are fewer associations and independent associations of bone pathologies with these important OA outcomes which may reflect fewer studies; for example the foot and ankle were poorly studied. Subchondral OA bone appears to be a relevant therapeutic target. Systematic review: PROSPERO registration number: CRD 4201300500
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