Optimization of a bogie primary suspension damping to reduce wear in railway operations

An optimization problem is formulated to attain the vector of optimized primary suspension passive dampers of a bogiein order to minimize wear in railway applications. A mechanical system with five degrees of freedom (DOF) comprising a single rigid wheelset attached to a fixed bogie frame is chosen to explore the effects of primary suspension damping components on wear. Different operational scenarios including tangent and curved tracks together with different levels of track irregularities are introduced to be used as inputs to model. The equations of motion of the system are obtained and the FASTSIM algorithm is employed to relate the creepages and the corresponding creep forces in different directions. At vehicle maximum admissible speed and a given set of operational scenarios, the optimized values of the primary suspension passive dampers in longitudinal, lateral and vertical directions are found through a genetic algorithm optimization routine in MATLAB. The outcomes of current research can not only be used to minimize wear in railway operation as well as reduce track access charges and maintenance costs, but also give insight into designingadaptive bogies

Numerical study of Effervescent atomization

Atomization is a process where the bulk of liquid jet disintegrates into liquid sheets, ligaments and droplets. It has enormous applications in industries and processes such as combustion, heat transfer systems, transport, biological systems and particularly our interest, coating processes. The Effervescent nozzle is a type of twin-fluid atomizer and has shown a superior performance in handling and spraying different liquids without any clogging issues; which is particularly interesting in thermal spray. In spite of significant number of experimental works, a few numerical works have been carried out. That makes it crucial to conduct a comprehensive numerical study on Effervescent atomizer. The complex internal and external behaviors of Effervescent atomizer are governing the behavior of the flow. The latter is a turbulent and compressible multiphase flow. It is studied numerically by employing a three-dimensional compressible Eulerian method along with Volume of Fluid (VOF) surface-tracking method coupled with the Large Eddy Simulation (LES) turbulence model. The numerical study is conducted by using OpenFoam library, an open-source package introduced by Open-CFD. In this study, the effect of varying the gas to liquid ratio (GLR) and the suspension (i.e. effect of viscosity, density and surface tension), on the structure of internal flow and consequently, the external flow is studied numerically. It is observed that the increase in GLR is accompanied with an evolution of the internal flow from a complex bubbly flow to an annular flow. This reduces the liquid film thickness at the discharge orifice. Further studies on internal pressure illustrated the critical condition, choked flow and pressure oscillations at the discharge orifice. The examination of increasing the GLR and evolving of internal flow resulted in changing in primary atomization parameters such as shortening the breakup length and widening the spray cone angle. Furthermore, the existence of a slip velocity between the two phases in the external flow results in dominant aerodynamic forces at high GLRs. Moreover, alternation of the liquid properties illustrated the higher spray velocity and wider cone angle of the spray, which demonstrates the superior performance of the Effervescent atomizer

An Efficient Rapid Method for Generators Coherency Identification in Large Power Systems

With steadily increasing interest in enhancing large power systems’ transient stability, generator coherency identification has become critical for the dynamic equivalents, controlled-islanding, and wide-area control of these systems. This paper presents an approach based on two classical and powerful techniques. The proposed method comprises the slow coherency method followed by the time-domain-based simulation of transient stability to identify the coherent groups of generators. In this regard, various operating conditions of the system are considered to obtain the updated coherency information between groups of generators by analyzing the chosen generator rotor angle. The proposed approach’s merits are tested on the New England IEEE 39-Bus and modified IEEE 118-Bus test systems in the PowerFactory software tools through Python. Corresponding simulation results validate the proposed paradigm’s effectiveness by enhancing the transient stability speed of a large power system without decreasing its coherency behavior accuracy. It is also observed that the proposed scheme tends to be more consistent in determining the coherent groups of generators in the presence of disturbances and different operational conditions.© 2022 the Authors. Published by IEEE. This work is licensed under a Creative Commons Attribution 4.0 License. For more information, see https://creativecommons.org/licenses/by/4.0/fi=vertaisarvioitu|en=peerReviewed

Comparative analysis of machine learning and numerical modeling for combined heat transfer in Polymethylmethacrylate

This study compares different methods to predict the simultaneous effects of conductive and radiative heat transfer in a Polymethylmethacrylate (PMMA) sample. PMMA is a kind of polymer utilized in various sensors and actuator devices. One-dimensional combined heat transfer is considered in numerical analysis. Computer implementation was obtained for the numerical solution of governing equation with the implicit finite difference method in the case of discretization. Kirchhoff transformation was used to get data from a non-linear equation of conductive heat transfer by considering monochromatic radiation intensity and temperature conditions applied to the PMMA sample boundaries. For Deep Neural Network (DNN) method, the novel Long Short Term Memory (LSTM) method was introduced to find accurate results in the least processing time than the numerical method. A recent study derived the combined heat transfers and their temperature profiles for the PMMA sample. Furthermore, the transient temperature profile is validated by another study. A comparison proves a perfect agreement. It shows the temperature gradient in the primary positions that makes a spectral amount of conductive heat transfer from a PMMA sample. It is more straightforward when they are compared with the novel DNN method. Results demonstrate that this artificial intelligence method is accurate and fast in predicting problems. By analyzing the results from the numerical solution it can be understood that the conductive and radiative heat flux is similar in the case of gradient behavior, but it is also twice in its amount approximately. Hence, total heat flux has a constant value in an approximated steady state condition. In addition to analyzing their composition, ROC curve and confusion matrix were implemented to evaluate the algorithm performance.Comment: 15 pages, 11 figure

When consumers love their brands: Exploring the consumers’ emotional characteristics on purchasing Apple mobile devices

This paper presents an empirical study to investigate the effect of emotional intelligence on customer’s adoption of Apple mobile devices. The study considers fife emotional dimensions including emotional management, self-adjustment, empathy, social skills and self-motivation using a standard questionnaire developed by Goleman (2006) [Goleman, D., & Sutherland, S. (1996). Emotional Intelligence: Why it can matter more than IQ. Nature, 379(6560), 34-34]. The study also uses another questionnaire, which measures love brand and both questionnaires are designed in Likert scale. Cronbach alphas for emotional intelligence and love brand are measured as 0.78 and 0.83, respectively, which are above the acceptance level of 0.70. Therefore, we can confirm the validity of both questionnaires. The study is implemented among 384 people who use Apple mobile device, randomly and using Spearman correlation ratio as well as stepwise regression techniques, the study has detected a positive and meaningful relationship between emotional intelligence and love brand for Apple mobile devices

Effect of Transformational Leadership and Knowledge Management Processes on Organizational Innovation in Ardabil University of Medical Sciences

Uncertainty, complexity, globalization and increasing technological change are among the most important features of the current era. Success in such circumstances requires changes in activities, organizational tasks, the management especially the leadership of organizations, knowledge management and innovation. The aim of this study was to investigate the effect of transformational leadership and knowledge management on organizational innovation in Ardabil University of Medical Sciences. Standard questionnaire was used in order to collect data for all variables of the research. Statistic population of this research consisted of all managers, employees, and faculty members of Ardebil University of Medical Sciences of whom 277 subjects were selected based on Cochran formula and convenience sampling method. For data analysis, structural equation modeling and LISREL software were used. The [1]obtained results showed that transformational leadership has a positive effect on knowledge management and organizational innovation. Moreover, the impact of knowledge management on organizational innovation was shown to be positive. Finally, the mediating role of knowledge management was confirmed in the relationship between transformational leadership and organizational innovatio

Electric Field Induced Alignment of Carbon Nanotubes: Methodology and Outcomes

In the current chapter, achievement of aligned carbon nanotube (CNT) network within the matrix via various kinds of electric fields (AC and DC) was evaluated. In this case, alignment mechanism of CNTs within the matrix and two useful techniques for justification of CNT alignment throughout the matrix were examined and presented, respectively. Afterward, effective factors in matter of CNT alignment and applicable procedures for fabrication of nanocomposites containing aligned CNTs were studied and presented, respectively. At the end, significant effects of CNT alignment on overall properties of nanocomposites that include electrical and mechanical properties were evaluated. Achieved results revealed that alignment of CNTs within the matrix can lead to significant improvement in the electrical and mechanical properties of nanocomposites at the same filler loading compared with randomly distribution of CNTs within the matrix, while production steps and conditions can also highly affect the outcome data

Internal Branding, Brand Citizenship Behavior and Customer Satisfaction: An Empirical Study (Case Study: Keshavarzi Bank of Ardabil)

Brand citizenship behavior is a new concept that explores the volunteer activities and activities which are outside the official duties of employees in the area of the organization’s brand. The aim of this study is to identify the relationship between internal branding, brand citizenship behavior and customer satisfaction in banking industry of Iran. Factors affecting brand citizenship behavior were considered in three categories: brand acceptance, brand enthusiasm and brand self- development; then, the influence of internal brand management on brand commitment, brand citizenship behavior and customer satisfaction was examined. Statistical population of the research consisted of 100 employees of Keshavarzi bank of Ardabil. Based on Morgan table, 84 employees were selected as the sample and finally 66 questionnaires were completed. In order to collect the required data related to all variables of the research, the standard questionnaire of Porricelli, Yurova, Abratt, and Bendixen (2014) and Orel and Kara (2014) was used. Using structural equation modeling and AMOS software, the research hypotheses were tested. The results obtained from this study show that internal brand management has a positive and significant impact on brand Commitment. Brand Commitment has a significant and positive impact on brand citizenship behavior and brand citizenship behavior has a significant and positive impact on customer satisfaction

Effect of Toxocara canis and Toxascaris leonina egg antigens on induction of eosinophilia in animal model

زمینه و هدف: توکسوکاراها و توکساسکاریس انگل روده سگ و گربه می باشند که لارو آن ها باعث ایجاد ائوزینوفیلی در انسان می شود. در این تحقیق به صورت اختصاری تأثیر آنتی ژن های تخم برخی از این انگل ها بر ایجاد ائوزینوفیلی بررسی شده است. روش بررسی: در این مطالعه تجربی تعداد 54 سر موش سوری در شش گروه قرار گرفتند. به گروه های مورد، آنتی ژن تخم توکسوکارا کانیس یا توکساسکاریس لئونینا بدون ادجونت از راه داخل صفاقی و یا همراه با ادجوانت فروندز از راه زیر جلدی تزریق شد. گروه های شاهد هیچ تزریقی دریافت نکردند. هر تزریق سه بار با فاصله زمانی دو هفته تکرار و بعد از هر تزریق، شمارش گلبول های سفید از نمونه های خونی انجام شد. یافته ها: اختلافی بین میانگین گلبول های سفید شامل لنفوسیت ها، ائوزینوفیل ها، نوتروفیل ها، مونوسیت ها و بازوفیل ها در گروه های مورد در مقایسه با گروه های شاهد مشاهده نگردید. نتیجه گیری: بر خلاف لاروها، آنتی ژن های انگل های مورد مطالعه باعث ائوزینوفیلی در موش ها نشدند؛ با این حال تحقیقات بیشتری در این خصوص توصیه می گردد