Hanif Heidari

In this study, lattice Boltzmann method (LBM) simulation is performed to investigate laminar forced convection of nanofluids in a horizontal parallel-plate channel with three rectangular cavities. Two cavities are considered as located on the top wall of the channel and one on the bottom wall. The effects of the Reynolds number (100-400), the cavity aspect ratio (AR = 0.25, 0.5), the various distances of the cavities from each other (Xc′) at different solid volume fractions of nanofluids (•=0 '0.05) on the velocity and the temperature profiles of the nanofluids are studied. In addition, the flow patterns, i.e. the deflection and re-circulation zone inside the cavities, and the local and averaged Nusselt numbers on the channel walls are calculated. The results obtained are used to ascertain the validity of the written numerical code, which points to the excellent agreement across the results. The results show that, as the solid volume fraction of nanofluids is enhanced, the transfer of heat to working fluids increases significantly. Further, the results show that the maximum value of the averaged Nusselt number in the channel is obtained at Xc′=0.1204 for AR = 0.5 and Xc′=0.1024 for AR = 0.25. The interval [0.1224, 0.1304] is the best position for the second cavity. It is concluded that the results of this paper are very useful for designing optimized heat exchangers. © World Scientific Publishing Company.

The present study classifies target users of Central Library of Isfahan to identify their behaviors and information needs. The research uses applied and descriptive-survey method with quantitative approach using neural network techniques in data-mining. The research tool was a researcher-made questionnaire including 64 items with the average reliability of Cronbach's alpha coefficient 0.862. The sample population consisted of 356 faculty members and graduate students of Isfahan University of Technology in the year 1393-94. Using MATLAB, they were clustered based on each of the main components of the study (the purpose and motivation of information-seeking, the amount of using information sources, information-seeking obstacles and skills, and the amount of using information services). Removing each of the research's sub-components of the main components demonstrated the highest purpose and motivation of information-seeking among the target population, and the least effective were reaching a scientific level and competition with rivals; the information sources mostly needed by library users were translations of Latin books, and their minimum requirements were reports and research schemes; the main barrier to their information-seeking was lack of access to proper Internet and the least effective factor in lack of access to information sources was inconvenient use of the sources; the skill of awareness about the required information and access to information channel are most efficient items in the information seeking skills. The most inefficient item is the ability of users in recognizing the importance of obtained information from their searches with respect to their required information; the most effective services in meeting the information needs of the users were the ability of librarians and information science experts in information retrieval and their knowledge of information services and resources, and the least effective were familiarity with a variety of information services and resources in their professional major and possibility of using the information sources in the form of digital files needless of attending libraries. According to the purpose and results of the present study, it is possible to classify target users of libraries via using neural network technique in data-mining, based on their needs and information-seeking behaviors.

The aim of this paper is investigating the forced convection heat transfer in a channel with transverse rectangular cavities using the lattice Boltzmann method (LBM) which is not available in the literature yet. The effects of the Reynolds number (100-400), cavity aspect ratio (AR=0.25, 0.5, 1.0), distance of cavities from each other (S′=0,2,4,6) in fixed depth of cavity (A′=0.5) on the velocity and temperature profiles are studied. Moreover, the flow patterns such as deflection and re-circulation zone inside the cavities are obtained. The local and averaged Nusselt numbers on the channel walls are achieved. The results show that the channel with cavities achieves heat transfer enhancements relative to the smooth channel. For the constant cavity aspect ratio, the maximum value of averaged Nusselt number in the channel is obtained in the case of S′=2. Heat transfer to the working fluids increases significantly by increasing the aspect ratio. The existed results are used to ascertain the validity of the numerical code and excellent agreement between results was found. © 2017 World Scientific Publishing Company.