排序方式： 共有78条查询结果，搜索用时 31 毫秒
31.
An extended discrete particle swarm optimization algorithm for the dynamic facility layout problem 总被引：2，自引：0，他引：2
Hassan Rezazadeh Mehdi Ghazanfari Mohammad Saidi-Mehrabad Seyed Jafar Sadjadi 《浙江大学学报(A卷英文版)》2009,10(4):520-529
We extended an improved version of the discrete particle swarm optimization （DPSO） algorithm proposed by Liao et al.（2007） to solve the dynamic facility layout problem （DFLP）. A computational study was performed with the existing heuristic algorithms, including the dynamic programming （DP）, genetic algorithm （GA）, simulated annealing （SA）, hybrid ant system （HAS）, hybrid simulated annealing （SA-EG）, hybrid genetic algorithms （NLGA and CONGA）. The proposed DPSO algorithm, SA, HAS, GA, DP, SA-EG, NLGA, and CONGA obtained the best solutions for 33, 24, 20, 10, 12, 20, 5, and 2 of the 48 problems from （Balakrishnan and Cheng, 2000）, respectively. These results show that the DPSO is very effective in dealing with the DFLP. The extended DPSO also has very good computational efficiency when the problem size increases. 相似文献
32.
Alireza Karimi Reza Razaghi Seyed Mohammadali Rahmati Toshihiro Sera Susumu Kudo 《Sports Engineering》2018,21(4):359-365
Eye injuries from blunt forces and penetrating objects can cause morbidity, disability, and blindness. Most of these injuries are preventable not only by understanding the detail of injury, but also by portraying the role of the ball’s characteristics. Basketball can induce severe forms of injuries to the eye. This study was aimed at performing a numerical analysis through the fluid–structure interaction on ocular trauma. Balls with different diameters, elastic moduli, and pressures were shot to the eye. Injury in terms of the stresses and deformations in each component of the eye was computed at ~?0.72 mm deformation in the apex of the cornea. By increasing the diameter of the ball from 20 to 26 cm the stress in the eye components, excluding the aqueous body, vitreous body, and extraconal fat, increased. Stresses of 2.68 and 3.19 MPa were observed in the cornea under the ball diameters of 20 and 26 cm, respectively. Conversely, the elastic modulus and pressure of the ball in the defined range showed no considerable role on the stress in the eye components. The results revealed the importance of the ball size compared to the elastic modulus and pressure in the stress accumulation as a result of ocular trauma. 相似文献
33.
Hani T. S. Benamer Amin Bredan Omran Bakoush 《Health information and libraries journal》2009,26(3):240-245
Background: It is well established that Libya is lagging behind its peers in biomedical research. The aim of this study is to analyse all the original biomedical publications affiliated with Libya from 1973 to 2007. Methods: PubMed and the Science Citation Index Expanded were searched for ‘original research’ biomedical studies affiliated with Libya. The generated data were hand searched and 329 ‘original research’ studies were included in the analysis. Results: The first study was published in 1973. Publication rate peaked to an average of 15.2 studies per year during 1986–1996 and dropped to an average of 8.8 studies per year during 1997–2007. Of 166 first authors; 41% were Libyans and 59% were expatriates. The latter contributed 104 studies between 1986 and 1996 and 36 studies between 1997 and 2007, while the Libyans contributed 63 and 61 studies in the two respective periods. Authors affiliated with Benghazi produced 67% of the published studies, while authors from Tripoli produced 30% and other medical schools, hospitals and research centres from other Libyan cities produced only 3%. Conclusion: This study showed a decline in biomedical research publication in Libya. We propose that the lack of a research culture among the Libyan medical professionals is one of the factors contributing to this decline, which coincided with the departure of expatriate doctors from Libya. Raising awareness of the importance of research and improving research skills among Libyan medical professionals may help to reverse the current trend. 相似文献
34.
Knowing in action: Beyond communities of practice 总被引：2，自引：0，他引：2
This paper engages with the recent turn in the social sciences towards communities of practice as a driver of learning and knowledge generation across a variety of different working environments. While agreeing with the broad reinstatement of situated social practice in thinking on the dynamics of knowledge capitalism, the paper takes issue with the increasingly homogeneous and instrumentalist use of the term communities of practice to encapsulate ‘knowing in action’. On the basis of an extensive review of the available literature, the paper argues for the importance of differentiating between different varieties of knowing in action. The paper notes the differences - in organisation, spatial dynamics, innovation outcomes, and knowledge processes - between four modes: craft or task-based knowing; epistemic or high creativity knowing; professional knowing; and virtual knowing. The proposed typology is used to illustrate the insight gained from such analytical precision, through a discussion of the spatial configuration of knowing in action, long assumed to require spatial proximity. It is shown that spatial and relational proximity - which can be struck at a distance - should not be treated as one and the same. 相似文献
35.
Adam Possamai Kevin Dunn Peter Hopkins Lisa Worthington Faroque Amin 《Journal of Higher Education Policy & Management》2016,38(6):637-648
Although there has been much research about the growing ethnic and religious diversity on university campuses across the world, relatively little is known about the religious and cultural experiences of Muslim students on university campuses in Australia. We draw upon an analysis of a questionnaire that was completed by 323 Muslim students who were studying at universities in the state of New South Wales, Australia. While we argue that these places are post-secular, we discovered that city campuses tend to be more secular than regional and suburban ones. 相似文献
36.
Abdul Hakeem Memon Mohammad Shahrul Ridzuan Hamil Madeeha Laghari Fahim Rithwan Salman Zhari Mohammed Ali Ahmed Saeed Zhari Ismail Amin Malik Shah Abdul Majid 《Journal of Zhejiang University. Science. B》2016,17(9):683-691
Syzygium campanulatum Korth is a plant, which is a rich source of secondary metabolites (especially flavanones, chalcone, and triterpenoids). In our present study, three conventional solvent extraction (CSE) techniques and supercritical fluid extraction (SFE) techniques were performed to achieve a maximum recovery of two flavanones, chalcone, and two triterpenoids from S. campanulatum leaves. Furthermore, a Box-Behnken design was constructed for the SFE technique using pressure, temperature, and particle size as independent variables, and yields of crude extract, individual and total secondary metabolites as the dependent variables. In the CSE procedure, twenty extracts were produced using ten different solvents and three techniques (maceration, soxhletion, and reflux). An enriched extract of five secondary metabolites was collected using n-hexane:methanol (1:1) soxhletion. Using food-grade ethanol as a modifier, the SFE methods produced a higher recovery (25.5%?84.9%) of selected secondary metabolites as compared to the CSE techniques (0.92%?66.00%). 相似文献
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38.
Mohammad Mohsen Shahmardan Mahmood Norouzi Mohammad Hassan Kayhani Amin Amiri Delouei 《浙江大学学报(A卷英文版)》2012,13(10):768-781
An exact analytical solution is obtained for convective heat transfer in straight ducts with rectangular cross-sections for the first time. This solution is valid for both H1 and H2 boundary conditions, which are related to fully developed convective heat transfer under constant heat flux at the duct walls. The separation of variables method and various other mathematical techniques are used to find the closed form of the temperature distribution. The local and mean Nusselt numbers are also obtained as functions of the aspect ratio. A new physical constraint is presented to solve the Neumann problem in non-dimensional analysis for the H2 boundary conditions. This is one of the major innovations of the current study. The analytical results indicate a singularity occurs at a critical aspect ratio of 2.4912 when calculating the local and mean Nusselt numbers. 相似文献
39.
Seyed Sahand SEBTI Mohammad MASTIANI Hooshyar MIRZAEI Abdolrahman DADVAND Sina KASHANI Seyed Amir HOSSEINI 《浙江大学学报(A卷英文版)》2013,14(5):307-316
A comprehensive numerical study was conducted to investigate heat transfer enhancement during the melting process in a 2D square cavity through dispersion of nanoparticles. A paraffin-based nanofluid containing various volume fractions of Cu was applied. The governing equations were solved on a non-uniform mesh using a pressure-based finite volume method with an enthalpy porosity technique to trace the solid-liquid interface. The effects of nanoparticle dispersion in a pure fluid and of some significant parameters, namely nanoparticle volume fraction, cavity size and hot wall temperature, on the fluid flow, heat transfer features and melting time were studied. The results are presented in terms of temperature and velocity profiles, streamlines, isotherms, moving interface position, solid fraction and dimensionless heat flux. The suspended nanoparticles caused an increase in thermal conductivity of nano-enhanced phase change material (NEPCM) compared to conventional PCM, resulting in heat transfer enhancement and a higher melting rate. In addition, the nanofluid heat transfer rate increased and the melting time decreased as the volume fraction of nanoparticles increased. The higher temperature difference between the melting temperature and the hot wall temperature expedited the melting process of NEPCM. 相似文献
40.
Hasan Ebrahimi Shahmabadi Seyed Kazem Bagherpour Doun Seyed Ebrahim Alavi Mehri Mortazavi Zahra Saffari Maryam Farahnak Azim Akbarzadeh 《Indian journal of clinical biochemistry : IJCB》2014,29(3):357-361
Emulsion polymerization was used to synthesize poly butyl cyanoacrylate nanoparticles in presence of steric stabilizer dextran 70. Nanoparticles were characterized by particle size analysis, scanning electron microscopy and light microscopy. Polymerization factors affecting particle size and distribution such as dextran 70, polysorbate 80 (PS 80) and H+ concentration, polymerization time and temperature, and sonication were studied. Distinct concentrations of stabilizer were needed to produce proper nanoparticles. In this case, the appropriate value was 2 % of total volume. At pH 4 significant decrease in production efficiency demonstrated the substantial effect of H+ concentration on nanoparticles. Furthermore significant increases in particle size and distribution was observed at 50 °C compared to room temperature. 0.001 % (v/v) PS 80 represented notable influence on size and distribution. In addition, shaped nanoparticles were obtained by altering polymerization time from 5.5 h to 18 h. Finally, nanoparticle features were influenced by different factors. Appropriate manipulating of such factors can lead to obtaining desirable nanoparticles. 相似文献