Finite element modeling of laser assisted friction stir welding of carbon steels for enhanced sustainability of welded joints

Part of: Seliger, Günther (Ed.): Innovative solutions : proceedings / 11th Global Conference on Sustainable Manufacturing, Berlin, Germany, 23rd - 25th September, 2013. - Berlin: Universitätsverlag der TU Berlin, 2013. - ISBN 978-3-7983-2609-5 (online). - http://nbn-resolving.de/urn:nbn:de:kobv:83-opus4-40276. - pp. 247-251.In Friction stir welding (FSW) of carbon steels, process parameters must be set to avoid defects such as warm holes. Proper selection of process parameters also affects the final grain microstructure and phase transformations and, ultimately, the weld’s mechanical properties. Process parameters, including laserassisted heating, of AISI 1045 carbon steel were investigated via a 3D finite element method (FEM) model. The laser action was modeled as heat source with constant flux. The simulation findings favorably agree with experiments reported in the literature and suggesting that with laser-assisted-FSW welding can be performed at higher traverse speeds (400 vs. 100 mm/min) while maintaining defect free weld. Also, evolved phase transformations are predicted across the weld geometry as time progresses. Such findings will help in the prediction of sound welding parameters and in estimating the mechanical properties of the various regions of the weld leading to more sustainable joints

Evidence-Based Practice: Knowledge, Attitude, Practice and Perceived Barriers to Practice among Nurses in Oman

OBJECTIVES: The aim of this study was to describe nurses’ practices, attitudes, knowledge/skills and perceived barriers in relation to evidence-based practice (EBP) in Oman. METHODS: This descriptive cross-sectional study was conducted between February and November 2012. A self-reported 24-item questionnaire was used to measure EBP practices, attitudes and knowledge/skills among a convenience sample of 600 nurses working in four governmental hospitals in Muscat, Oman. Responses were scored on a one to seven rating scale. Barriers to EBP were measured on a five-point Likert scale using two subscales. Descriptive statistics and general linear regression were used to analyse the data. RESULTS: A total of 414 nurses were included in the study. The greatest barriers to developing EBP among nurses were insufficient time for research (3.51 ± 0.97) and insufficient resources to change practices (3.64 ± 0.99). Nurses with more years of experience reported increased use of EBP (P <0.01), more positive attitudes towards EBP (P <0.001) and fewer barriers to research (P <0.01). Significant positive correlations were found between years of experience and practice (r = 0.16) and attitudes (r = 0.20). Nurses with a baccalaureate degree reported fewer barriers to research than those qualified at a diploma level (P <0.001). Nurses who perceived more barriers to research reported less use of EBP (P <0.001), less positive attitudes towards EBP (P <0.001) and limited EBP knowledge/skills (P <0.001). CONCLUSION: These findings provide a basis for enhancing nursing practices, knowledge and skills. Continuing education for nurses and minimising barriers is crucial to increasing the use of EBP in Oma

Авіаційна навігаційна система на основі поляриметричних технологій

The paper deals with questions of developing polarimetric navigation method for determiningaircraft’s coordinates. This method, potentially, can increase the accuracy and sensitivity of navigationparameters determination. The paper also deals with existing methods and systems for determining aircraft’snavigation parameters and proposed polarimetric method. Also offered block diagrams of the onboardand ground polarimetric device. In article were given result of the mathematical modeling of measuringchannelРассмотрен вопрос разработки поляриметрического навигационного метода для определения координат воздушного судна. Этот метод, потенциально, позволяет повысить точность и чувствительность определения навигационных параметров. Рассмотрены существующие методы и системы и предложен поляриметрический методдля определения навигационных параметров летательного аппарата. Предложена блок-схема бортового и наземного поляриметрического устройства. Приведены результаты математического моделирования измерительного каналаРозглянуто питання розроблення поляриметричного навігаційного методу для визначення координат повітряного судна. Цей метод, потенційно, дозволяє підвищити точність та чутливість визначення навігаційних параметрів. Розглянуто існуючі методи і системи та запропоновано поляриметричний метод для визначення навігаційних параметрів літального апарату. Запропоновано блок-схему бортового і наземного поляриметричного пристрою. Приведено результати математичного моделювання вимірювального канал

Evidence-Based Practice : Knowledge, attitudes, practice and perceived barriers among nurses in Oman

Objectives: The aim of this study was to describe nurses’ practices, attitudes, knowledge/skills and perceived barriers in relation to evidence-based practice (EBP) in Oman. Methods: This descriptive cross-sectional study was conducted between February and November 2012. A self-reported 24-item questionnaire was used to measure EBP practices, attitudes and knowledge/skills among a convenience sample of 600 nurses working in four governmental hospitals in Muscat, Oman. Responses were scored on a one to seven rating scale. Barriers to EBP were measured on a five-point Likert scale using two subscales. Descriptive statistics and general linear regression were used to analyse the data. Results: A total of 414 nurses were included in the study. The greatest barriers to developing EBP among nurses were insufficient time for research (3.51 ± 0.97) and insufficient resources to change practices (3.64 ± 0.99). Nurses with more years of experience reported increased use of EBP (P &lt;0.01), more positive attitudes towards EBP (P&lt;0.001) and fewer barriers to research (P &lt;0.01). Significant positive correlations were found between years of experience and practice (r = 0.16) and attitudes (r = 0.20). Nurses with a baccalaureate degree reported fewer barriers to research than those qualified at a diploma level (P &lt;0.001). Nurses who perceived more barriers to research reported less use of EBP (P &lt;0.001), less positive attitudes towards EBP (P &lt;0.001) and limited EBP knowledge/skills (P &lt;0.001). Conclusion: These findings provide a basis for enhancing nursing practices, knowledge and skills. Continuing education for nurses and minimising barriers is crucial to increasing the use of EBP in Oman

Knowledge of Coronary Heart Disease Risk Factors among a Community Sample in Oman : Pilot study

Objectives: The aim of this study was to assess the knowledge of Omani adults regarding conventional coronary heart disease (CHD) risk factors and to identify demographic variables associated with these knowledge levels. Methods: This descriptive cross-sectional pilot study was carried out among a convenience sample of 130 adults attending a health awareness fair held in a local shopping mall in Muscat, Oman, in November 2012. A modified version of the Heart Disease Facts Questionnaire in both English and Arabic was used to assess knowledge of CHD risk factors. Scores were calculated by summing the correct answers for each item (range: 0–21). Inadequate knowledge was indicated by a mean score of &lt;70%. Descriptive and multivariate logistic regression analyses were performed to establish the participants’ knowledge levels and identify associated demographic variables. Results: A total of 114 subjects participated in the study (response rate: 87.7%). Of these, 69 participants (60.5%) had inadequate mean CHD knowledge scores. Knowledge of CHD risk factors was significantly associated with body mass index (odds ratio [OR] = 0.739; P = 0.023), marital status (OR = 0.057; P = 0.036) and education level (OR = 9.243; P = 0.006). Conclusion: Low knowledge levels of CHD risk factors were observed among the studied community sample in Oman; this is likely to limit the participants’ ability to engage in preventative practices. These findings support the need for education programmes to enhance awareness of risk factors and prevention of CHD in Oman

Probabilistic models reliability of information and control systems

The paper deal with devoting the problem of reliability prediction and modeling the functioning process of information and control systems (ICS), which are described by the Markov random process. The methodology of the study consist in considering ICS as Markov systems. Modeling the functioning process of information and control systems will increase authenticity and reliability of information from the ICS, as well as improve the efficiency of its work. As an example, the mathematical model of the functioning the computer system of the dispatch service is constructed in the paper. Mathematical modeling was conducted in the environment of MathCad. Mathematical modeling allows determining the average number of steps before system moves into the absorbing state. Taking into account the length of stay the system in each condition allows determining the average life of the system until the full failure. The development of model and technology for calculating the characteristics of stochastic systems allows investigating a wide class of such systems and determining optimal maintenance operation term in order to ensure reliability and reduce the waste on downtime