35 research outputs found

    The Geometrical Analysis Accuracy for Parallel Robotic Mechanisms

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    The geometrical analysis of the robotic mechanisms means the formulation of the position equation of the mechanism in terms of dependent and independent coordinates. This function should describe the position of its links and the end effecter (or moving platform center) in terms of dependent and independent coordinates.In this paper will be derived a mathematical model, that is, a model in terms of dependent and independent generalized coordinates, for the position accuracy of the end effecter (platform) of the closed kinematics robotic mechanisms. In these types of mechanisms it is necessary to solve the inverse problem of the geometrical analysis. The solving of the inverse problem in the robotic systems means the definition of independent coordinates on preset values and evaluation of the dependent coordinates with several degrees of mobility. The aim of this paper is to obtain a new mathematical formulation for evaluation of the deviation of the end effecter position due to the deviation of the independent coordinates. It will be evaluated only the deformations of the arms caused by the weights and the forces

    A review of offshore wind turbines: global added capacity, monopile structure foundations stresses and deflection

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    Offshore wind power is now a significant source of clean renewable energy. The paper summarizes the key findings from recent energy studies on the growth in offshore wind power's added capacity to the global energy system. The review paper referred to parts of the configuration of offshore wind turbines (OWTs) and their supporting structures, and focused on the monopole support structure due to its importance in building offshore wind farms and studying and discussing the most published research related to the mono support structure and its response to wind loads and wave loads affecting them. Recent studies have varied between numerical analysis research, research and master's theses and doctoral theses on calculating stresses on offshore wind turbines. Due to the importance of the topic, studies on computational fluid dynamics (CFD), which have developed greatly in recent years, have been reviewed (simulation and simulation research). Hybrids (RTHS) and experimental research. The paper concluded with the conclusion that the interest in experimental studies and research close to the conditions of marine turbines is through the construction of special laboratories that include advanced equipment with quantitative measurements, with high technical standards and good reliability, developments of simulation tools of various forms in order to approach efficient and low-cost design

    Presentation and outcome of Middle East respiratory syndrome in Saudi intensive care unit patients.

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    BACKGROUND: Middle East respiratory syndrome coronavirus infection is associated with high mortality rates but limited clinical data have been reported. We describe the clinical features and outcomes of patients admitted to an intensive care unit (ICU) with Middle East respiratory syndrome coronavirus (MERS-CoV) infection. METHODS: Retrospective analysis of data from all adult (>18 years old) patients admitted to our 20-bed mixed ICU with Middle East respiratory syndrome coronavirus infection between October 1, 2012 and May 31, 2014. Diagnosis was confirmed in all patients using real-time reverse transcription polymerase chain reaction on respiratory samples. RESULTS: During the observation period, 31 patients were admitted with MERS-CoV infection (mean age 59 ± 20 years, 22 [71 %] males). Cough and tachypnea were reported in all patients; 22 (77.4 %) patients had bilateral pulmonary infiltrates. Invasive mechanical ventilation was applied in 27 (87.1 %) and vasopressor therapy in 25 (80.6 %) patients during the intensive care unit stay. Twenty-three (74.2 %) patients died in the ICU. Nonsurvivors were older, had greater APACHE II and SOFA scores on admission, and were more likely to have received invasive mechanical ventilation and vasopressor therapy. After adjustment for the severity of illness and the degree of organ dysfunction, the need for vasopressors was an independent risk factor for death in the ICU (odds ratio = 18.33, 95 % confidence interval: 1.11-302.1, P = 0.04). CONCLUSIONS: MERS-CoV infection requiring admission to the ICU is associated with high morbidity and mortality. The need for vasopressor therapy is the main risk factor for death in these patients

    Constructing public health policies in post crisis countries: lessons to learn from the associations between free-sugars consumption and diabetes, obesity and dental caries before, during and after sanctions in Iraq.

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    BACKGROUND: This article aims to provide evidence for an informed public health policy on free-sugar consumption in post-crisis countries. METHODS: Iraq was selected as a case study. A systematic search for published data on the prevalence/incidence of type-2 diabetes, overweight/obesity, dental caries and free-sugar consumption levels in Iraq was conducted using MEDLINE, the Iraqi Academic Scientific journals and relevant international organisations' websites. Comparable data before (1980-1990), during (1991-2002) and after (2003-2015) the United Nations sanctions (UNS) were included. RESULTS: Ten studies were included. Quality scores ranged between 3 and 7/8. Free-sugar consumption decreased dramatically during the UNS (from 50 to 16.3 kg/person/year) and started increasing afterwards (24.1 kg/person/year). Changes in type-2 diabetes, overweight/obesity and caries levels mirrored those of free-sugar consumption. Caries declined markedly during UNS and started increasing afterwards. Comparable data on diabetes and overweight/obesity were only available for the periods during and after the UNS. Both of these conditions started increasing with increased free-sugar consumption after lifting the UNS. CONCLUSIONS: There is a need to develop a public health policy in post-crisis countries to maintain the reduction in free-sugar consumption, and hence promote both general and dental health, by integrating the common risk factor approach into the social determinant framework

    The Role of Neighborhood Environment in Promoting Risk Factors of Cardiovascular Disease among Young Adults: Data from Middle to High Income Population in an Asian Megacity

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    Background: Modifiable risk factors of cardiovascular diseases (CVD) have their triggers in the neighborhood environments of communities. Studying the environmental triggers for CVD risk factors is important to understand the situation in a broader perspective. Young adults are influenced the most by the environment profile around them hence it is important to study this subset of the population.Methods: This was a descriptive study conducted using the EPOCH research tool designed by the authors of the PURE study. The study population consisted of young adults aged 18-25 in two areas of Karachi. The study setting was busy shopping malls frequented by young adults in the particular community being studied.Results: Our total sample size was 120 individuals, who consented to be interviewed by our interviewers. Less than 50% of the population recognized some form of restriction regarding smoking in their communities. The largest contributor to tobacco advertising was actors smoking in movies and TV shows with 89% responses from both communities. Only 11.9% of the individuals disapproved of smoking cigarettes among men with wide acceptance of \u27sheesha\u27 across all age groups. Advertising for smoking and junk food was more frequent as compared to smoking cessation, healthy diet and exercise in both the areas. Unhealthy food items were more easily available in contrast to healthier options. The cost of healthy snack food options including vegetables and fruits was higher than sugary drinks and foods.CONCLUSION: This assessment showed that both communities were exposed to environments that promote risk factors for cardiovascular diseases

    Burnout among surgeons before and during the SARS-CoV-2 pandemic: an international survey

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    Background: SARS-CoV-2 pandemic has had many significant impacts within the surgical realm, and surgeons have been obligated to reconsider almost every aspect of daily clinical practice. Methods: This is a cross-sectional study reported in compliance with the CHERRIES guidelines and conducted through an online platform from June 14th to July 15th, 2020. The primary outcome was the burden of burnout during the pandemic indicated by the validated Shirom-Melamed Burnout Measure. Results: Nine hundred fifty-four surgeons completed the survey. The median length of practice was 10 years; 78.2% included were male with a median age of 37 years old, 39.5% were consultants, 68.9% were general surgeons, and 55.7% were affiliated with an academic institution. Overall, there was a significant increase in the mean burnout score during the pandemic; longer years of practice and older age were significantly associated with less burnout. There were significant reductions in the median number of outpatient visits, operated cases, on-call hours, emergency visits, and research work, so, 48.2% of respondents felt that the training resources were insufficient. The majority (81.3%) of respondents reported that their hospitals were included in the management of COVID-19, 66.5% felt their roles had been minimized; 41% were asked to assist in non-surgical medical practices, and 37.6% of respondents were included in COVID-19 management. Conclusions: There was a significant burnout among trainees. Almost all aspects of clinical and research activities were affected with a significant reduction in the volume of research, outpatient clinic visits, surgical procedures, on-call hours, and emergency cases hindering the training. Trial registration: The study was registered on clicaltrials.gov "NCT04433286" on 16/06/2020

    Reliability measurement for mixed mode failures of 33/11 kilovolt electric power distribution stations.

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    The reliability of the electrical distribution system is a contemporary research field due to diverse applications of electricity in everyday life and diverse industries. However a few research papers exist in literature. This paper proposes a methodology for assessing the reliability of 33/11 Kilovolt high-power stations based on average time between failures. The objective of this paper is to find the optimal fit for the failure data via time between failures. We determine the parameter estimation for all components of the station. We also estimate the reliability value of each component and the reliability value of the system as a whole. The best fitting distribution for the time between failures is a three parameter Dagum distribution with a scale parameter [Formula: see text] and shape parameters [Formula: see text] and [Formula: see text]. Our analysis reveals that the reliability value decreased by 38.2% in each 30 days. We believe that the current paper is the first to address this issue and its analysis. Thus, the results obtained in this research reflect its originality. We also suggest the practicality of using these results for power systems for both the maintenance of power systems models and preventive maintenance models
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