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( Hedayat Panah Ahmad ) 한국수학교육학회 2012 수학교육 학술지 Vol.2012 No.1
The aim of this research paper is to study about Guilan University students` skills in mathematics lesson according to Bloom`s recognition compasses. Statistical samples were 241 university students (males and females) from different branches of technical major who answered mathematics questions from whatever they had learned before entering the university. The Exam included 50 multiple choice questions which were designed and classified due to Benjamin Bloom`s recognition compasses, Results show that: a) Students had the best performance in science, understanding (perception) and application, but they had the least performance in evaluation and judgment, analysis and combination. b) Girls had the most performance in understanding (perception) and application compasses but in other compasses, boys had better performance.
Abbastabar, Hedayat,Roustazadeh, Abazar,Alizadeh, Ali,Hamidifard, Parvin,Valipour, Mehrdad,Valipour, Ali Asghar Asian Pacific Journal of Cancer Prevention 2015 Asian Pacific journal of cancer prevention Vol.16 No.9
Background: Colorectal cancer (CRC) is the third most common cancer in Iranian women and fifth in men. The aims of this study were to investigate the relation of dietary factors and public health indicators to its development. Materials and Methods: The required information (2001-2006) about risk factors was obtained from the Non-Communicable Disease Surveillance Centre (NCDSC) of Iran. Risk factor data (RFD) from 89,404 individuals (15-64 years old) were gathered by questionnaire and laboratory examinations through a cross sectional study in all provinces by systematic clustering sampling method. CRC incidence segregated by age and gender was obtained from Cancer Registry Ministry of Health (CRMH) of Iran. First, correlation coefficients were used for data analysis and then multiple regression analysis was performed to control for confounding factors. Results: Colorectal cancer incidence showed a positive relationship with diabetes mellitus, hypertension, lacking or low physical activity, high education, high intake of dairy products, and non-consumption of vegetables and fruits. Conclusions: We concluded that many dietary factors and public health indicators have positive relationships with CRC and might therefore be targets of preliminary prevention. However, since this is an ecological study limited by potential ecological fallacy the results must be interpreted with caution.
Afshin Hedayat 한국원자력학회 2017 Nuclear Engineering and Technology Vol.49 No.5
In this paper, a complete station blackout (SBO) or complete loss of electrical power supplies is simulatedand analyzed in a downward cooling 5-MW pool-type Material Testing Reactor (MTR). The scenario istraced in the absence of active cooling systems and operators. The code nodalization is successfullybenchmarked against experimental data of the reactor's operating parameters. The passive heat removalsystem includes downward water cooling after pump breakdown by the force of gravity (where thecoolant streams down to the unfilled portion of the holdup tank), safety flapper opening, flow reversalfrom a downward to an upward cooling direction, and then the upward free convection heat removalthroughout the flapper safety valve, lower plenum, and fuel assemblies. Both short-term and long-termnatural core cooling conditions are simulated and investigated using the RELAP5 code. Short-term analysesfocus on the safety flapper valve operation and flow reversal mode. Long-term analyses includesimulation of both complete SBO and long-term operation of the free convection mode. Results arepromising for pool-type MTRs because this allows operators to investigate RELAP code abilities for MTRthermalehydraulic simulations without any oscillation; moreover, the Tehran Research Reactor isconservatively safe against the complete SBO and long-term free convection operation.
Abbastabar, Hedayat,Hamidifard, Parvin,Roustazadeh, Abazar,Mousavi, Seyyed Hamid,Mohseni, Shokrallah,Sepandi, Mojtaba,Barouni, Mohsen,Alizadeh, Ali Asian Pacific Journal of Cancer Prevention 2013 Asian Pacific journal of cancer prevention Vol.14 No.9
Background: Breast cancer is one the most common cause of cancer-related deaths among women worldwide. The aims of this study were to investigate the impact of dietary factors and health status indicators on breast cancer (BC) incidence. Materials and Methods: Risk factor data (RFD) of 89,404 individuals (15-64 years old) were gathered by questionnaire and laboratory examinations through a cross sectional study from the Non-Communicable Disease Surveillance Centre (NCDSC) of Iran. BC incidences of all provinces through 2001-2006 segregated by age and gender were obtained from the Cancer Registry Ministry of Health (CRMH). Results: a significant positive relationship was seen between diabetes mellitus, fish comsupmption, percent of academic education and non-consumption of fruit, and breast cancer in women. However, non fish consumption, percent age illiteracy and taking fruit showed a significant negative relationship with the incidence of breast cancer. In addition, multiple linear regression analysis showed associations among percentage with academic education, fruit consumption and diabetes. Conclusions: We conclude that dietary factors such as fish and furit consumption, dairy products, health status indicators, academic education, and some diseases like diabetes mellitus can affect the BC incidence, although the results of ecologic studies like this must naturally be interpreted with caution.
Inhibition of Human Hemoglobin Autoxidaiton by Sodium n-Dodecyl Sulphate
Reza, Dayer Mohammad,Ali Akbar, Moosavi-Movahedi,Parviz, Norouzi,Ghourchian, Ghourchian,Hedayat-Olah, Hedayat-Olah,Shahrokh, Safarian 생화학분자생물학회 2002 Journal of biochemistry and molecular biology Vol.35 No.4
The effect of sodium n-dodecyl sulphate (SDS) on hemoglobin autoxidation was studied in the presence of a 100mM phosphate buffer (pH 7.0) by different methods. These included spectorphotometry, fluorescence technique, cyclic voltametry, differential scanning calorimetry, and densitometry. Spectroscopic studies showed that SDS concentrations up to 1 mM increased deoxy-, decreases oxy-, and had no significant effect on the met- conformation of hemoglobin. Therefore, a SDS concentration up to 1 mM increased the deoxy form of hemoglobin as the folded, compact state and decreases the oxy conformation. The turbidity measurements and differential scanning calorimetry techniques indicated a more stable conformation for hemoglobin in the presence of SDS up to 1mM. Electrochemical studies also confirmed a more difficult oxidation under these conditions. The induction of the deoxy form in the presence of SDS was confirmed by densitometry techniques. The compact structure of deoxyhemoglobin blocks the formation of met-conformation in low SDS concentrations.
Students` Field-dependency and Their Mathematical Performance based on Bloom`s Cognitive Levels
( Alamolhodael Hassan ),( Hedayat Panah Ahmad ),( Radmehr Farzad ) 한국수학교육학회 2011 수학교육연구 Vol.15 No.4
Students approach mathematical problem solving in fundamentally different ways, particularly problems requiring conceptual understanding and complicated strategies. The main objective of this study is to compare students` performance with different thinking styles (Field-dependent vs. Field independent) in mathematical problem solving. A sample of 242 high school males and females (17-18 years old) were tested based on the Witkin`s cognitive style (Group Embedded Figure Test) and by a math exam designed in accordance with Bloom`s Taxonomy of cognitive level. The results obtained indicated that the effect of field dependency on student`s mathematical performance was significant. Moreover, field-independent (Fl) students showed more effective performance than field-dependent (FD) ones in math tasks. Male students with H styles achieved higher results compared to female students with FD cognitive style. Moreover, H students experienced few difficulties than FD students in Bloom`s Cognitive Levels. The implications of these results emphasize that cognitive predictor variables (H vs. FD) could be challenging and rather distinctive factor for students` achievement.
Upgraded salp swarm algorithm for optimal design of semi-active MR dampers in buildings
Farzad Raeesi,Hedayat Veladi,Bahman Farahmand Azar,Sina Shirgir,Baharak Jafarpurian 국제구조공학회 2023 Structural Engineering and Mechanics, An Int'l Jou Vol.86 No.2
In the case of designing control devices in a building, reliance on experimental formulation or engineering concepts without using optimization algorithms leads to non-optimal solutions or design parameters, which makes the use of control devices costly and unreasonable. The optimization algorithms are capable of identifying the required number of parameters for a specific design problem, however, this process is difficult and inefficient in dealing with some specific optimal design processes. This paper aims to introduce an upgraded version of the salp swarm algorithm to handle some engineering design. The performance of the new upgraded algorithm is tested using some benchmark test functions as well as a six-story benchmark building equipped with semi-active MR dampers. The simulation results show that the proposed algorithm can be successfully applied to get an optimal design of the MR dampers in the building.
Enhancement of supercritical carbon dioxide solubility models using molecular simulation data
Hojatollah Moradi,Nariman Rezamandi,Hedayat Azizpour,Hossein Bahmanyar,Kamran Keynejad,Zahra Nasrollahi 한국화학공학회 2022 Korean Journal of Chemical Engineering Vol.39 No.3
Supercritical carbon dioxide (SC-CO2) has been used in a broad range of industrial applications due to its unique properties, which underlines the importance of understanding its exact behavior under different operating conditions. In this study, the solubility parameter (SP) of SC-CO2 was calculated using molecular dynamics simulation at varying temperature and pressure and different concentrations of methanol as a co-solvent. The obtained simulation results were used to create a model for solubility parameter using response surface methodology (RSM). These data were then used to improve three available empirical correlations of SC-CO2’s solubility parameter. The resulting equations were vastly superior in predicting the solubility parameter with an average coefficient of determination of 96.33%.
Selecting optimized concrete structure by Analytic Hierarchy Process (AHP)
Morteza Ebrahimi,Amir Ahmad Hedayat,Hamed Fakhrabadi 사단법인 한국계산역학회 2018 Computers and Concrete, An International Journal Vol.22 No.3
Increase in population and its daily increasing in our today society results in an increase in housing demand while traditional methods are not applicable. The project preparation and realization processes, based on theoretical and empirical studies, a creation of goods, services, and technologies, are the most important human activities. Selection of effective technological systems in construction is a complex multi-criteria decision-making task. Many decision-makers refuse innovations once faced with similar difficulties. Therefore, using modern materials and methods in this industry is necessary. Modern methods increase quality and construction speed in addition to decrease energy consumption and costs. One of the problems in the way of any project is selecting construction system compatible with the project needs and characteristics. In the present research, different concrete structures such as common reinforced concrete (RC) structure, prefabricated, Insulating Concrete Formwork (ICF), 3D Panel and Tunnel Concrete Formwork (TCF) for buildings with limited floors in Iran are studied and compared from the viewpoint of different criteria like cost, time, applicability and technical characteristics with industrialization approach. Therefore, some questionnaires filled out by construction industry experts in order to compare criteria and sub-criteria in addition to evaluation of optimized structural systems. Then, results of the questionnaires ranked by Analytic Hierarchy Process (AHP) and the most effective alternative selected. The AHP results show that 3D Panel system 36.5%, ICF 21.7%, TCF 19.03%, prefabricated system 13.3% and common RC system 9.3% are the most and the least efficient systems respectively.
( Seyed Mohammad Mahdavi ),( Hedayat Sahraei ),( Parichehreh Yaghmaei1 ),( Hassan Tavakoli ) 한국응용약물학회 2014 Biomolecules & Therapeutics(구 응용약물학회지) Vol.22 No.6
Studies have demonstrated that electromagnetic waves, as the one of the most important physical factors, may alter cognitive and non-cognitive behaviors, depending on the frequency and energy. Moreover, non-ionizing radiation of low energy waves e.g. very low frequency waves could alter this phenomenon via alterations in neurotransmitters and neurohormones. In this study, short, medium, and long-term exposure to the extremely low frequency electromagnetic field (ELF-EMF) (1 and 5 Hz radiation) on behavioral, hormonal, and metabolic changes in male Wistar rats (250 g) were studied. In addition, changes in plasma concentrations for two main stress hormones, noradrenaline and adrenocorticotropic hormone (ACTH) were evaluated. ELF-EMF exposure did not alter body weight, and food and water intake. Plasma glucose level was increased and decreased in the groups which exposed to the 5 and 1Hz wave, respectively. Plasma ACTH concentration increased in both using frequencies, whereas noradrenaline concentration showed overall reduction. At last, numbers of rearing, sniffing, locomotor activity was increased in group receiving 5 Hz wave over the time. In conclusions, these data showed that the effects of 1 and 5 Hz on the hormonal, metabolic and stress-like behaviors may be different. Moreover, the influence of waves on stress system is depending on time of exposure.