bluuebunny/crossref_metadata_2025 huggingface dataset:
PAFNÚTIY LVÓVITCH TCHEBYSHEV E O NASCIMENTO DA ESCOLA RUSSA EM TEORIA DOS NÚMEROS
Authors: Morey Bernadete , Sultanov Adgam
Published: November 2020

O artigo tem o objetivo de apresentar a pessoa e a obra de Pafnútiy Lvóvitch Tchebyshev aliada à sua importante contribuição no desenvolvimento da matemática e na formação de uma escola russa em Teoria dos Números.
O PROFESSOR UNIVERSITÁRIO PORTUGUÊS DO INÍCIO DO SÉCULO XX: O CASO PARADIGMÁTICO DE VICENTE GONÇALVES
Authors: Costa Cecília
Published: November 2020

Em Portugal, o conceito de professor universitário de ciências matemáticas foi mudando ao longo do tempo, especialmente durante o século XX. Do professor universitário que apenas se dedicava à docência e que transmitia os conhecimentos clássicos; aquele que tem diversas vertentes a cumprir, como a de investigador, de autor, de gestor, de divulgador, etc.; encontramos casos de professores universitários que marcaram pela sua atuação profissional. Apresentamos o caso paradigmático do professor universitário português J. Vicente Gonçalves (1896-1985).
REFLEXÃO SOBRE AS VICISSITUDES DE MATEMÁTICOS EM PERÍODOS BÉLICOS: O CASO DE JOSÉ SEBASTIÃO E SILVA
Authors: Costa Cecília
Published: November 2020

A reflexão histórica que apresentamos surgiu da leitura de duas cartas de Sebastião e Silva para Vicente Gonçalves, escritas em Roma, em agosto de 1945 e em março de 1946. Sebastião e Silva permaneceu nesta cidade, de 1943 a 1946, como bolseiro para desenvolver investigação com vista ao doutoramento. Período em que a Europa vivia a II Guerra Mundial. Não temos conhecimento de algum estudo que contextualize essa fase da vida deste Matemático no período bélico que se vivia. É, pois, o que fazemos neste artigo, partindo do testemunho na primeira pessoa de Sebastião e Silva sobre as vicissitudes vividas nessa altura.
O PRIMEIRO DOUTOR EM CIÊNCIAS MATEMÁTICAS NO BRASIL: MANUEL DA CUNHA GALVÃO
Authors: Martines Mônica de Cássia Siqueira
Published: November 2020

Neste artigo, pretendemos relatar parte da pesquisa de Doutorado defendido no ano de 2014, referente ao primeiro Bacharel em Matemáticas a obter o título de Doutor em Ciências Matemáticas. Nossa busca foi impulsionada por tentar compreender a Matemática que foi desenvolvida nas Teses de Doutorado apresentadas à Escola Militar entre 1842 e 1858 no Brasil. No entanto, para compreendermos o por quê deste grau no Brasil, iniciamos uma pesquisa sobre a Academia Real Militar. Queríamos saber como ela fora criada, quais mudanças teriam ocorrido ao longo dos anos e como surgiu a ideia de conceder o grau dedoutor em Ciências Matemáticas. Através das leituras dos decretos e leis sobre a Academia Real Militar e suas reformas, percebemos uma série de decretos que atualizaram e deram novas diretrizes a Academia Real Militar a transformando em 1839 em Escola Militar e, em 1842 nessa escola, instituiu-se o grau de Doutor em Ciências Matemáticas. Neste ano e nos seguintes, até 1846, os professores da referida escola receberam o título sem outra exigência qualquer. Com a publicação da Regularização de 29 de setembro de 1846, são dadas orientações àqueles que desejassem obter o título de Doutor. Nesse contexto queapresentamos Manuel da Cunha Galvão, que em 22 de dezembro de 1847, entregava sua dissertação de doutorado ao Dr. José Gomes Jardim e, no dia 28 de maio de 1848, recebe seu grau de Doutor na presença do Imperador D. Pedro II.
Knowledge, attitudes and practice in the field of the radiation protection of medical radiology engineers in radiotherapy
Authors: Topčagić Muhamed , Šoše Amer , Tinjak Enis , Zovko Marin , Čizmić Haris
Published: November 2020

Introduction: The engineers of the medical radiology in radiotherapy are key professional group directly responsible for reliable delivery of radiation therapy treatment and the implementation of radiation protection measures in practice. Therefore, their knowledge and skills in this area need to be adequate and up to date. The aim of this research is the assessment of knowledge, attitudes and practice in the field of radiation protection among the engineers of medical radiology employed in radiotherapy centers within the public healthcare system in Bosnia and Herzegovina.Material and methods: The research was conducted on a sample of 30 engineers of medical radiology using a structured questionnaire which contains demographic data and sets of 10 questions related to radiotherapy devices, radiation protection in radiotherapy, risks and incidents related to use of ionizing radiation and the role of medical radiology engineers in radiation protection system.Results: The results of the research show optimal level of knowledge in the field of radiation protection (74.66%) and optimal level of awareness of the risks associated with the use of ionizing radiation (72%). The level of knowledge and awareness is significantly higher among respondents with longer working experience and those who have completed master’s degree and postgraduate education in the field of radiation protection. The application of ionizing radiation protection measures in practice has been assessed as satisfactory (2,3). Respondents are not sufficiently involved in the work of regulatory bodies (26.7%), decisionmaking (23.3%), development of procedures (23.3%) and education of other employees in the field of radiation protection (2.7%).Conclusion: Engineers of medical radiology are not fully involved in the radiation protection system as educated and trained professionals. One of the most important professional interests of engineers of medical radiology is adequate influence on the processes in the field of radiation protection.
The significance of mammography and ultrasound examination in the diagnosis of breast cancer
Authors: Petrić Mirko , Šehić Adnan , Čatović Ismira
Published: November 2020

Introduction: Mammography represents a very accessible diagnostic method that has been accepted as the initial method of examining women over the age of 40 worldwide. It is a method with a high percentage of accuracy (80-90%) in the detection of breast cancer in patients without symptoms. However, there may be a significant overlap of mammographic presentation of benign and malignant changes in the structural tissue of the breast. The ultrasound method of breast examination is invaluable in breaking down between solid and cystic changes, as well as for clarifying palpable lumps in the breast. In almost 98% of cases, ultrasound examination can distinguish whether it is a benign or malignant change. The aim of this study is to prove the correlation between mammography and ultrasound methods of breast examination.Material and methods: The examination was performed as a retrospective - prospective descriptive study in the Department for radiological and ultrasound diagnostics of the Derventa Health Center. The study included 80 female respondents who consented to the recording. Based on the performed ultrasound and mammography images, a qualitative analysis was made. A comparison of the sensitivity of the breast imaging between mammography and ultrasound imaging was performed.Results: Comparing mammography and ultrasound examination according to BI-RADS classification, based on Pearson's correlation coefficient, we concluded that there is a strong correlation between these two tests (r = 0.743), which is statistically significant (p <0.005). The correlation, in addition to having a strong connection, moves in a positive direction, that is, by increasing the value of BI-RADS of one diagnostic procedure, there is an increase in another.Conclusion: By analyzing the obtained results, we can conclude that mammography and ultrasound methods of breast examination are complementary methods, which complement each other, and which are not perfect. However, these two methods certainly have their place in breast cancer screening.
The mechanical thrombectomy during coil embolisation of the ruptured intracranial aneurysm
Authors: Bulja Deniz , Abud Odej Ali , Jusufbegović Merim , Vegar - Zubović Sandra
Published: November 2020

Experience in managing thromboembolic complications of distal blood vessels during coil embolization in the case of subarachnoid hemorrhage (SAH) is still limited. This is the presentation of the case of a 23-year-old man with a ruptured small aneurysm who experienced thromboembolic occlusion during coil embolization. Mechanical thrombectomy resulted in complete recanalization of the occluded branches without ischemic complications. This case should be used for the use of mechanical thrombectomies as an effective rescue strategy and treatment of distal arteries occlusions of the brain.
The Impact of using social media in a sample of Iraqi medical students in 2019
Authors: Almawashee Ali , Yousif Qaswer , Ali Idan Karrar
Published: November 2020

Abstract

Background:

 Social media are tools that supports electronic conversation. suggested , social media are “a group of internet-based applications that build on the ideological and technological foundations of Web 2.0, that allow the creation and exchange of User Generated Content.

Aim of the study:

Is to identify the pattern of usage of social media among a sample of Iraqi medical students including the devices used, the time consumed, and   the purpose of usage.

Materials &Methods:

The study, which is a retrospective cross-sectional, was conducted among medical students at college of Medicine\Baghdad University at 2019 as an online survey for duration of 3 months

Data was entered and analyzed using spss version 24.Informed consent was obtained from the participants and the study was approved by the research committee in the college.

Results

The mean age of the participants in this study was 20.8 with sd 1.78. Results had shown no significant association between the usefulness of social media for educational values and type of social media, device used, and the time spent on these media.

Results had shown that those who use social media more frequently were not significantly worried about the potential of social media abuse.

Conclusions

A study exploring more objectively the relationship between students’ use of social media with their academic achievements and what sort of social media interventions associated with better learning are probably needed. Such knowledge may be useful to guide medical educators to better utilize social media in their instructional strategies.
Analyze predisposing risk factor of breast cancer(BC) among Iraqi women in Baghdad teaching hospital and oncology unit center in Baghdad
Authors: Zuhair Ahmed , Khudyair Rabab , Abdulsamad Rania
Published: November 2020

Abstract

Background: Breast cancer is the most frequent malignancy in women worldwide .in Iraq Breast cancer ranks first among cancer diagnosed in women, the goal of this study is to bring the lights towards the importance of most common risk factors to reduce the incidence of breast cancer.

Materials and methods: A case control study of breast cancer women who attended oncology unit and Baghdad educational hospital in Baghdad between first of June 2018, and first of September 2018, the  cases were (60) and control (90) all of them use formula that contain (marital status of women, age, occupation, parity, age of first child, age of menarche,  of menopause, smoking, use of contraceptive pills, body mass index, family history of breast cancer) and cases was all had medical records available. We use SPSS version 23. Each parameter is compared separately for statistically significant differences.

Results: In this study show that the mean age of cases (48.30) and the mean of control (34.42) .

And as we show the domiation from house wife with percentage (71%) regarding case but the control also show like this percentage.

The BMI show so close mean between case (28.1) and control (27.07) and has no effect on disesas , the martial status was 84.7% of both cases and control  so no statisticaly significant, the gravity, abortion and breast feeding show no significant differences.

The family history shows highly significant, in case show (24) person from (60) have family member with diseas, most of them have (sister) with BC .

Radiation and smoking show no statistically differences, regarding radiation only 14 women of all sample had exposure to radiation from different source.  The contraceptive show significant differences there is (35) of case from (60) use contraceptive drug they have breast cancer.

Conclusion: The majority of women with breast cancer were had been in the 5th decade

and we show in this study no relation between smoking and BC, women with family history has more risk to have BC. Contraceptive pills is also strong predictor of Breast cancer.
A Novel Neutral Point Clamped Full-Bridge Topology for Transformerless Photovoltaic Grid-Connected Inverters
Authors: Pakdel M. , Jalilzadeh S.
Published: November 2020

This paper presents a novel neutral point clamped full-bridge topology for transformerless photovoltaic grid-tied inverters. Transformerless grid-connected inverters have been used widely in recent years since they offer higher efficiency and lower costs. Ground leakage current suppression is the main issue which should be considered carefully in transformerless photovoltaic grid-connected inverters. Among different methods used to decline ground leakage current, neutral point clamped (NPC) topologies are considered more useful and effective. In NPC topologies, the short-circuited output voltage at the freewheeling period is clamped to the middle of the DC bus voltage. Therefore, the common-mode voltage (CM) will be constant at the whole switching period. Various NPC topologies such as H6 [1], HB-ZVR [2], oH5 [3], and PN-NPC [4] have been proposed. In this paper, a novel NPC topology is proposed which has lower power losses and higher efficiency over previous topologies. Furthermore, the proposed NPC topology exhibits a similar ground leakage current with the PN-NPC topology. The proposed NPC topology is analyzed theoretically using simulation studies and an experimental prototype is provided to verify theoretical analysis and simulation studies.
Effect of Supply Chain Information Systems on Firm Performance: An Empirical Case Study
Authors: Kashani F. H. , Baharmast S.
Published: November 2020

This study evaluates the effect of supply chain information systems on firm performance in IKAMCO as a empirical case study. For this purpose, The 132 IKAMCO employees selected by simple random sampling responded to a questionnaire. Content validity of the questionnaire has been confirmed by experts in this field; its reliability has been confirmed by using Cronbach's alpha and Fisher’s test. Kolmogorov-Smirnov test is used to ensure normality of the data obtained from questionnaire. The hypotheses are tested using SmartPLS software. Results show that the model is well fitted to the data. Findings show that a lean and agile supply chain is effective on supply chain performance and supply chain performance is effective on firm performance. Efficiency of information systems moderates the effect of lean supply chain on supply chain performance and firm performance. However, flexibility of information systems does not moderate the effect of agile supply chain on supply chain performance and firm performance.
Taxonomy of Manufacturing Flexibility at Manufacturing Companies Using Imperialist Competitive Algorithms, Support Vector Machines and Hierarchical Cluster Analysis
Authors: Khoobiyan M. , Pooya A. , Tavakkoli A. , Rahimnia F.
Published: November 2020

Manufacturing flexibility is a multidimensional concept and manufacturing companies act differently in using these dimensions. The purpose of this study is to investigate taxonomy and identify dominant groups of manufacturing flexibility. Dimensions of manufacturing flexibility are extracted by content analysis of literature and expert judgements. Manufacturing flexibility was measured by using a questionnaire developed to survey managers of manufacturing companies. The sample size was set at 379. To identify dominant groups of flexibility based on dimensions of flexibility determined, Hierarchical Cluster Analysis (HCA), Imperialist Competitive Algorithms (ICAs) and Support Vector Machines (SVMs) were used by cluster validity indices. The best algorithm for clustering was SVMs with three clusters, designated as leading delivery-based flexibility, frugal flexibility and sufficient plan-based flexibility.
Performance of Geosynthetic-Reinforced Soils Under Static and Cyclic Loading
Authors: Touahmia M.
Published: November 2020

This paper investigates and discusses the composite behavior of geosynthetic reinforced soil mass. It presents the results of a series of large-scale laboratory tests supported by analytical methods to examine the performance of geogrid reinforcement subjected to static and cyclic pullout loading. The testing equipment and procedures used for this investigation are outlined. The results show that geosynthetic reinforcement can mobilize great resistance to static pulling load under high confining pressures. The reinforcement exhibits gradual deformation under cyclic loading showing no sign of imminent pullout failure for all levels of applied loads. In general, the results demonstrate that geosynthetic can be used in situations where loads are non-static, although care will be required in ensuring that appropriate factors of safety are applied to control the resulting deformation. A simplified analytical model for calculating the pulling capacity of geosynthetic reinforcement is proposed.
Renewable Energy Systems: Development and Perspectives of a Hybrid Solar-Wind System
Authors: Subrahmanyam J. B. V. , Alluvada P. , Bandana . , Bhanupriya K. , Shashidhar C.
Published: November 2020

Considering the intermittent natural energy resources and the seasonal un-balance, a phtovoltaic-wind hybrid electrical power supply system was developed to accommodate remote locations where a conventional grid connection is inconvenient or expensive. However, the hybrid system can also be applied with grid connection and owners are allowed to sell excessive power back to the electric utility. The proposed set-up consists of a photo-voltaic solar-cell array, a mast mounted wind generator, lead-acid storage batteries, an inverter unit to convert DC to AC, electrical lighting loads, electrical heating loads, several fuse and junction boxes and associated wiring, and test instruments for measuring voltages, currents, power factors, and harmonic contamination data throughout the system. The proposed hybrid solar-wind power generating system can be extensively used to illustrate electrical concepts in hands-on laboratories and also for demonstrations in the Industrial Technology curriculum. This paper describes an analysis of local PV-wind hybrid systems for supplying electricity to a private house, farmhouse or small company with electrical power depending on the site needs. The major system components, work principle and specific working condition are presented.
Effect of Standard No. 2800 Rules for Moment Resisting Frames on the Elastic and Inelastic Behavior of Dual Steel Systems
Authors: Veladi H. , Najafi H.
Published: November 2020

According to most valid Design Codes including the Iranian Seismic Design Code (Standard No. 2800), moment resisting frames in dual systems must have the ability of resisting the 25% of the total lateral load of the dual system independently. This study is conducted to investigate the implementation of this rule for dual steel structures with two types of steel braced frame. Also, its effect on the strength of the structure and the distribution of lateral load between the frames and the bracing system is evaluated. In order to investigate the effect of that rule, structural models with 5, 10 and 15 floors are modeled. Nonlinear static analysis is employed and results are discussed. Following the Standard No. 2008 seems to increase the structure’s lateral resistance and decrease the number of elements entered into the inelastic behavior stage. In general, the structure has a more desirable inelastic behavior.
An Assessment of Students’ Satisfaction Level from Learning Management Systems: Case Study of Payamnoor and Farhangian Universities
Authors: Shayan P. , Iscioglu E.
Published: November 2020

Learning Management Systems (LMS) have played a significant role in education. The purpose of this study is to investigate the acceptance level of LMS amongst students of two Universities in Tehran, Payamnoor and Farhangian. The total number of participants was 200. This study was directed based on a quantitative research method and data collection from a questionnaire which was then interpreted according to accurate statistical procedures through SPSS software. Results show that most students, regardless their gender, age, and department were satisfied with the usage of Payamnoor and Farhangian LMSs. However, a student’s grades seem to play a significant role regarding his or hers level of satisfaction from the LMS.
Measuring the Success Level and Effectiveness of Knowledge Management in Organizations: A Case Study
Authors: Mesbah A. , Babaei M. , Shabanali A.
Published: November 2020

Knowledge management is a systematic approach to improve organizational ability to mobilize knowledge and facilitate decision-making in setting business strategy. This study identifies the outcomes of an effectively implemented knowledge management in one of the departments of ‘Iran Khodro’ as an empirical case study. Effective factors on effectiveness of knowledge management and effective outcomes of knowledge management were extracted by a semi-structured interview in three questions with 20 experts. Then, results of interviews and the factors extracted from literature were integrated; by removing similar factors, 52 factors were identified and organized in three groups. Using exploratory Delphi analysis in two stages (by expert’s judgments), 30 out of 52 factors extracted from literature and interview were identified as outcomes of knowledge management implemented in the organizations; these factors were evaluated through a second questionnaire in 32 questions for prioritization of their significance in the studied organization by experts and managers. Based on the coefficient calculated for the confirmed factors in three groups of outcomes, the top priority was knowledge, followed by human resource- organization and performance, respectively. Ranking of the rest is explained below.
Temperature Response in Hardened Concrete Subjected to Tropical Rainforest Environment
Authors: Egba E. I. , Ismail M. , Bakhary N.
Published: November 2020

The objective of this paper is to characterize concrete micro-environment temperature response to the natural climate of the tropical rainforest. The peculiar warmth, high humidity, and low pressure nature of the tropical rainforest necessitated the present study. Temperature probes were inserted into concrete specimens subjected to the sheltered and unsheltered environment to measure the micro-environment temperature of the concrete, and study the hysteresis characteristics in relation to the climate temperature. Some mathematical relationships for forecasting the internal temperature of concrete in the tropical rainforest environment were proposed and tested. The proposed relationships were found reliable. It was observed that the micro-environment temperature was lower at the crest, and higher at the trough than the climate environment temperature with a temperature difference of 1-3 oC. Also, temperature response in concrete for the unsheltered micro-environment was 1.85 times faster than the response in the sheltered micro-environment. The findings of the study may be used to assist the durability assessment of concrete.
Effect of Adaptation Gain in Model Reference Adaptive Controlled Second Order System
Authors: Swarnkar P. , Jain S. , Nema R. K.
Published: November 2020

Adaptive control involves modifying the control law used by the controller to cope with the fact that the parameters of the system being controlled change drastically due to change in environmental conditions or in system itself. This technique is based on the fundamental characteristic of adaptation of living organism. The adaptive control process is one that continuously and automatically measures the dynamic behavior of plant, compares it with the desired output and uses the difference to vary adjustable system parameters or to generate an actuating signal in such a way so that optimal performance can be maintained regardless of system changes. Nature of adaptation mechanism for controlling the system performance is greatly affected by the value of adaptation gain. It is observed that for the lower order system wide range of adaptation gain can be used to study the performance of the system. As the order of the system increases the applicable range of adaptation gain becomes narrow. This paper deals with application of model reference adaptive control scheme to second order system with different values of adaptation gain. The rule which is used for this application is MIT rule. Simulation is done in MATLAB and simulink and the results are compared for varying adaptation mechanism due to variation in adaptation gain.
Numerical Investigation of Fluid Flow and Heat Transfer Inside a 2D Enclosure with Three Hot Obstacles on the Ramp under the Influence of a Magnetic Field
Authors: Keshtkar M. M. , Ghazanfari M.
Published: November 2020

This paper focuses on solving the fluid flow and heat transfer equations inside a two-dimensional square enclosure containing three hot obstacles affected by gravity and magnetic force placed on a ramp using Boltzmann method (LBM) applying multiple relaxation times (MRT). Although, the Lattice Boltzmann with MRT is a complex technique, it is a relatively new, stable, fast and high-accurate one. The main objective of this research was to numerically model the fluid flow and ultimately obtaining the velocity field, flow and temperature contour lines inside a two-dimensional enclosure. The results and their comparisons for different types of heat transfer revealed that free or forced heat transfer has a considerable impact on the heat transfer and stream lines. This can be controlled by modifying the Richardson number. It is revealed that changing the intensity of the magnetic field (Hartman number) has an appreciable effect on the heat transfer.
Effect of Applied Pressure on the Mechanical Properties of 6061 Aluminum Alloy Welded Joints Prepared by Friction Stir Welding
Authors: Al-jarrah J. A. , Ibrahim A. , Sawlaha S.
Published: November 2020

This paper investigates the effect of axial force on the surface appearance and mechanical properties of 6061 aluminum alloy welded joints prepared by friction stir welding. The applied pressure varies from 1.44 to 10.07 MPa. The applied pressure was calculated from the axial force which exerted by a spring loaded cell designed for this purpose. Defect free joints obtained at an applied pressure of 3.62 MPa. The mechanical properties of the welded joints were evaluated through microhardness and tensile tests at room temperature. From this investigation, it was found that the joint produced with an applied pressure of 5.76 MPa exhibits superior tensile strength compared to other welded joints. The fracture of this joint happened at the base material.
Environmental Risk Assessment and Management in Oil Platform Construction Phase Activities: A Case Study
Authors: Younesi A. , Rahmani R. , Jaafari J. , Mahdavi Y.
Published: November 2020

The construction phase is one of the very risky stages engaged in oilfields, which usually involves minor to severe human, financial, and environmental damages. It includes a major part of lost working times, and in recent years, along with the development of oilfields and oil platform construction activities in Iran, hazardous risks and events have occurred and have been recorded. Therefore, this study aims to reduce the negative effects of the risks engaged in oil platform construction activities in the region under study, i.e. the Abuzar oilfield. The indexing system method, along with determining the importance index, effect, and frequency of occurrence, was used in this study to evaluate the environmental risks of oil platform construction activities in Abuzar oilfield. First, the project activities were identified and then, the effect of desired activities on environmental aspects (water, air, soil, human, waste production, and noise) was investigated. For quantitative estimation of risk values through interviewing the experts and using the tables of intensity, effect, and frequency of event occurrence, were calculated based on the formula governing the effect of different activities on the environment, and the risk value was determined. The research findings indicated that most of the environmental risks are in the range of average risks (72.9%) however 20.2% are in the range of low risks and 6.9% are in the range of high risks. Finally, considering experts’ viewpoints, management solutions were proposed to reduce the risk of activities, and the risk priority numbers were calculated after performing the corrective actions.
Perceived Possibility of Disclosure and Ethical Decision Making in an Information Technology Context
Authors: Bolhari A. , Radfar R. , Alborzi M. , Poorebrahimi A. , Dehghani M.
Published: November 2020

To date, substantial research studies have been conducted in the field of ethical decision making in many disciplines. However, ethical efforts in the context of information technology have been limited. In this research, a focus has been put on modeling ethical decision making in cyberspace with emphasis on business intelligence scenarios. The model is comprised of six exogenous and two endogenous constructs, among them seven were delicately selected from valid and empirically tested ethical models and the eighth one is developed by the authors. After pre-testing the model by experts, reliability, convergent and discriminant validities were approved. Data were collected from 188 IT personnel in the banking industry of Iran. Results revealed that the perceived importance of an IT ethical issue, ethical judgment, ethical obligation, perceived possibility of disclosure, ego strength, and locus of control directly impact ethical intention. However, no impact from law on ethical obligation and codes of ethics on ethical intention was observed. As shown, a higher possibility on acting unethically occurs when the person feels confident that his/her actions will go unnoticed.
Application of Fuzzy Expert Systems to Manage the Projects Time in Iranian Gas Refineries
Authors: Naderpour A. , Sardroud J. M. , Mofid M.
Published: November 2020

The National Iranian Gas Company (NIGC) is one of the top ten gas companies in the gas industry in the Middle East and is comprised of 7 gas refineries. So this company needs to apply the most optimum time management methods to achieve its goals. Custom scheduling calculation of project planning uses the Critical Path Method (CPM) as a tool for Planning Projects activities. CPM is now widely used in planning and managing projects but in spite of its wide application, this method has a critical weak point of not taking into account the uncertainties in scheduling calculation. This article aims to present a precise method based on the application of Fuzzy Expert Systems in order to improve the Time Estimation Method in construction projects and in this regard, reviews the results of the implementation of this method in construction projects of Iranian Gas Refineries. The results show that the proposed method increases the accuracy of time estimation about 7 to 22 percent.
Hopf Bifurcation Control of Subsynchronous Resonance Utilizing UPFC
Authors: Alomari Μ. Μ. , Widyan M. S. , Abdul-Niby M. , Gheitasi A.
Published: November 2020

The use of a unified power flow controller (UPFC) to control the bifurcations of a subsynchronous resonance (SSR) in a multi-machine power system is introduced in this study. UPFC is one of the flexible AC transmission systems (FACTS) where a voltage source converter (VSC) is used based on gate-turn-off (GTO) thyristor valve technology. Furthermore, UPFC can be used as a stabilizer by means of a power system stabilizer (PSS). The considered system is a modified version of the second system of the IEEE second benchmark model of subsynchronous resonance where the UPFC is added to its transmission line. The dynamic effects of the machine components on SSR are considered. Time domain simulations based on the complete nonlinear dynamical mathematical model are used for numerical simulations. The results in case of including UPFC are compared to the case where the transmission line is conventionally compensated (without UPFC) where two Hopf bifurcations are predicted with unstable operating point at wide range of compensation levels. For UPFC systems, it is worth to mention that the operating point of the system never loses stability at all realistic compensation degrees and therefore all power system bifurcations have been eliminated.
Comparative Study of Prestress Losses
Authors: Boukendakdji M. , Touahmia M. , Achour M.
Published: November 2020

This paper compares the prestress losses as calculated by four different design codes; British standard CP110, Comite Europeen du Beton 70 and 78, American Concrete Institute 77 and the Prestressed Concrete Institute method (PCI). The comparison is done by determining the total losses which take place in a rectangular prestressed concrete beam for both pre-tensioning and post-tensioning systems. The results show that total losses calculated for the post-tensioning method are higher than those calculated for the pre-tensioning method, which is not the usual case. It seems that the PCI method may be required for special structures or for simply supported slender members which may be sensitive to small changes in deflections. However, for non-special structures, or where actual losses have little effect on the design, it is better to compute losses by the ACI method because it is simple and does take into considerations interactions between the various sources of losses. However, it is not possible to conclude which method gives the more accurate prediction of shrinkage and creep without direct co-relation to realistic insitu data.
Designing an Optimal Lightning Protection Scheme for Substations Using Shielding Wires
Authors: Khodadadi A. , Nazari M. H. , Hosseinian S. H.
Published: November 2020

An optimal lightning protection scheme for a substation using shielding wires is investigated in this paper through computer software analysis. An economic approach is utilized by choosing a reasonable trade-off between protection, the number of shielding wires and the heights of them from the ground. This study is initially applied to a simple two-wire system and then extended to a sample substation. The solution for each problem is executed in MATLAB and 3-D realization is shown.
A Low Cost Automated Weather Station for Real Time Local Measurements
Authors: Abdul-Niby M. , Farhat M. , Abdullah M. , Nazzal A.
Published: November 2020

In this paper, we present an automated weather station for real time and local measurements, based on an embedded system that continuously measures several weather factors such as temperature, humidity, barometric pressure, wind speed, wind direction, and rainfall. This weather station consists of two parts which are located indoor and outdoor and connected together wirelessly. The outdoor weather station measures the current temperature, humidity, barometric pressure, wind speed, wind direction and recent rain amount. The indoor station displays the outdoor reading as well as the temperature and humidity for the room it is located in, on a graphic liquid crystal display. In addition, this weather information can be accessed from any place through an iOS and Android application called Blynk.
Influence of Field Spacer Geometry on the Performance of a High Voltage Coaxial Type Transmission Line with Solid Dielectric Spacer in Vacuum
Authors: Anagha A. P. , Sunitha K.
Published: November 2020

With the development of more powerful high power electromagnetic sources, the transmission of high voltage power particularly between pulsed power systems to huge power rated microwave sources in absence of electrical breakdown and pulse distortion has begun to become a vital issue. A high voltage coaxial type transmission line with 500 kV peak voltage in vacuum is proposed. A novel proposal of configuration bearing a positive angle of 45o with socket-type filed shaper is being discussed in this paper in a manner to improve surface flashover properties and also to decrease the distortion seen in the pulse shape. This type of transmission line provides high capability of hold off voltage. The electric field distribution of the coaxial geometry with different field shaper configurations and different spacer parameters are also investigated using COMSOL software.
The Role of Export Entrepreneurship Effective Factors in Export Performance
Authors: Asghari E. , Rostami A. R. R.
Published: November 2020

This research aims to investigate the role of export entrepreneurship effective factors in export performance. Research statistical population contains sales managers and top managers working in manufacturing companies of precious and decorative stones in Firuzeh, a city in Iran. In order to gather data, a questionnaire consisting of 32 questions has been used. The validity of the questionnaire was confirmed by supervisors and advisors and its reliability has been assessed (0.865) using Cronbach’s alpha coefficient. Five hypotheses have been proposed for this research. Two methods of descriptive and inferential statistics have been used to analyze the data in this study. In the descriptive part, frequency number, frequency percentage, and frequency graph have been employed. Statistical analysis on data collected show that the variables of management commitment, resources, and the intensity of competition have significant positive impact on export entrepreneurship while the variable market distance does not have significant positive impact on export entrepreneurship. In addition, export entrepreneurship has a significant positive impact on export performance.
Case Study of Effectiveness Evaluation of Staff Training Courses in Refah Bank
Authors: Yousefian E. , Chitsaz A. , Karimpour B.
Published: November 2020

One of the newest and most well-known train patterns for evaluating the effectiveness of in-service staffs training is Kircpatrick model. In this paper, the effectiveness of staff training courses of Refah-bank is evaluated. A questionnaire consisted of five components which include: reaction, learning, of behavior, the results and the innovation in role of confounding factors is handed out. The survey results show that three factors (reactions, behavior and innovation) have a significant effect on the teachings effectiveness according to Kircpatrick model. And that two factors (learning and results of the courses) have not a significant effect.
A Compact Quint-Band Bandpass Filter Based on Stub-Loaded Resonators
Authors: Farhat M. , Munisami J. , Abdul-Niby M. , Nahas M.
Published: November 2020

This paper presents a planar quant-band bandpass filter with a high out-of-band rejection. The filter is based on inter-coupled stub-loaded resonators, where pairs of resonators are electromagnetically coupled to each other and the feed lines. This results in excitation of passbands, where the first and the third passbands are generated by λ/4 stub-loaded resonators. The second and the fifth passbands are excited by λ/2 stub-loaded resonators. And the fourth passband is generated by λ/2 resonators. The proposed technique provides sufficient degree of freedom to control the center frequency and bandwidth of the five passbands. In addition, the seven transmission zeros created around the passbands results in a quant-band filter with high selectivity, sharp 3dB cut-off frequency, high isolation, and low passband insertion-loss. Design methodology and simulation results of the filter are provided.
A Numerical Study of Gas Injection and Caprock Leakage from Yort-e-Shah Aquifer in Iran
Authors: Rad H. S. , Rajabi M. , Masoudian M. S.
Published: November 2020

In order to mitigate the adverse effects of global warming due to anthropogenic CO2 emission into the atmosphere, geological sequestration of CO2 into subsurface formations has been investigated by many studies over the last decade. However, selection of formations and sites for any field application is still open to debate. The most important properties of a formation suitable for carbon sequestration are those which impact the fluid flow processes. The injection or extraction of gas can change the pore pressure within the reservoir, which in turn results in redistribution of the stress field. These events may cause considerably leakage of the fluid into the surrounding geological formations or ground surface. The main objective of this paper is to evaluate the potential of Yort-e-Shah aquifer for CO2 storage, through a series of analyses with a simplified numerical model. The numerical results suggest that the optimum injection pressure in Yort-e-Shah aquifer is about 15.51 MPa with a safety factor of about 1.7. The results of the fluid pressure and gas plume expansion are presented. Also, an analysis was carried out for a case with leak through cap rock. When there is no leak, the pressure within the aquifer is stable, while on the other hand, the pressure in case of leakage is slightly smaller. In case of leakage, the pressure is lowest in the middle of the reservoir, mainly because the nodes at the middle of the aquifer are influenced by all the leakage points, while around the wellbore or near the end of gas plume, are affected less due to their longer distance to leakage points.
Using Ecotech Architecture as an Effective Tool for Sustainability in Construction Industry
Authors: Mozhdegani A. S. , Afhami R.
Published: November 2020

Ecotech architecture can be used as an effective strategy to minimize energy consumption and enhance the satisfaction of construction industry beneficiaries in the Middle East. The use of ecotech principles has been employed in different parts of the world. However, following a universal approach is not possible as local conditions are always to be considered Applications and examples of ecotech architecture are investigated in this paper. A proposed building design for the Cheetgar region in Tehran is also briefly demonstrated. A further insight on Masdar city in Abhu Dabi is provided. An overall discussion is made and key conclusions are drawn.
An Investigation on the Ultimate Strength of Cold-Formed Steel Bolted Connections
Authors: Konkong N.
Published: November 2020

This paper presents experimental results and finite element analysis of the cold-formed steel bolted connection under shear loading. Experiments are conducted to study the ultimate behaviors, such as ultimate strength and failure mode of connections. The samples were fabricated into three different groups, single bolted, double bolted and quadruple bolted connection. Material properties were determined by tensile coupon testing. Bearing failure modes were detected in the bolted connection tests. The ultimate capacities were compared with the nominal strengths calculated using the AISI (2012). The comparisons show that the nominal strength parameters predicted by this specification is conservative. The finite element analysis shell elements were used to model the cold-formed steel plate while solid elements were used to model the bolted fastenings for the purpose of studying the structural behavior of bolted connections. Material nonlinearities, contact problem and geometry nonlinearities analysis are carried out in order to predict ultimate strength and failure mode of connections. The results show that the proposed model accurately represents the failure mode and ultimate strength of bolted connection, as determined from experimental investigation. The new factor for type of bearing connection has a good agreement with the tested bearing strength of bolt connection.
Hybrid Semantic Analysis of Tweets: A Case Study of Tweets on Girl-Child in India
Authors: Madhukar M. , Verma S.
Published: November 2020

Social networks have become one of the major and important parts of daily life. Besides sharing ones views the social networking sites can also be very efficiently used to judge the behavior and attitude of individuals towards the posts. Analysis of the mood of public on a particular social issue can be judged by several methods. Analysis of the society mood towards any particular news in form of tweets is investigated in this paper. The key objective behind this research is to increase the accuracy and effectiveness of the classification by the process of Natural Language Processing (NLP) Techniques while focusing on semantics and World Sense Disambiguation. The process of classification includes the combination of the effect of various independent classifiers on one particular classification problem. The data that is available in the form of tweets on twitter can easily frame the insight of the public attitude towards the particular tweet. The proposed work implements a hybrid method that includes Hybrid K, clustering and boosting. A comparison of this scheme versus a K-means/SVM approach is provided. Results are shown and discussed.
Design and Performance Analysis of Multi-tier Heterogeneous Network through Coverage, Throughput and Energy Efficiency
Authors: Shabbir A. , Khan H. R. , Ali S. A. , Rizvi S.
Published: November 2020

The unprecedented acceleration in wireless industry strongly compels wireless operators to increase their data network throughput, capacity and coverage on emergent basis. In upcoming 5G heterogeneous networks inclusion of low power nodes (LPNs) like pico cells and femto cells for increasing network’s throughput, capacity and coverage are getting momentum. Addition of LPNs in such a massive level will eventually make a network populated in terms of base stations (BSs).The dense deployments of BSs will leads towards high operating expenditures (Op-Ex), capital expenditure (Cap-Ex) and most importantly high energy consumption in future generation networks. Recognizing theses networks issues this research work investigates data throughput and energy efficiency of 5G multi-tier heterogeneous network. The network is modeled using tools from stochastic geometry. Monte Carlo results confirmed that rational deployment of LPNs can contribute towards increased throughput along with better energy efficiency of overall network.
Secure Data Encryption Through a Combination of AES, RSA and HMAC
Authors: Harba E. S. I.
Published: November 2020

Secure file transfer based upon well-designed file encryption and authorization systems expend considerable effort to protect passwords and other credentials from being stolen. Transferring and storing passwords in plaintext form leaves them at risk of exposure to attackers, eavesdroppers and spyware. In order to avoid such exposure, powerful encryption/authentication systems use various mechanisms to minimize the possibility that unencrypted credentials will be exposed, as well as be sure that any authentication data that does get transmitted and stored will be of minimal use to an attacker. In this paper we proposed a method to protect data transferring by three hybrid encryption techniques: symmetric AES algorithm used to encrypt files, asymmetric RSA used to encrypt AES password and HMAC to encrypt symmetric password and/or data to ensure a secure transmitting between server-client or client-client from verifying in-between client and server and make it hard to attack by common attacked methods.