Blended Learning Researches in Iran: Several Fundamental Criticisms

The present study seeks to critically review the state of the blended learning researches in the Iranian context. For this critique, 47 papers about blended learning were found in a number of indexing databases and their contents were analyzed. The contents mainly revolved around use of relevant terminology, features of blended learning, methodology, levels of blended learning, variables of the study, and the analyzed educational programs. Some major criticisms that can be leveled at these studies include limited range of terminology, inappropriate use of key concepts, overemphasis on quantitative methods, overuse of pseudo-empirical method, lack of case studies, mistaking blended learning for application of computers in education, excessive concentration on the level of educational programs, superficial treatment of the distinction between learning and retaining, lack of attention to some of the variables of blended learning, and use of blended learning for primary and secondary education

Balancing collective responsibility, individual opportunities and risks: a qualitative study on how police officers reason around volunteering in an HIV vaccine trial in Dar es Salaam, Tanzania

Results from HIV vaccine trials on potential volunteers will contribute to global efforts to develop an HIV vaccine. The purpose of this study among police officers in Dar es Salaam, Tanzania, was to explore the underlying reasons that induce people to enrol in an HIV vaccine trial.\ud We conducted discussions with eight focus groups, containing a total of 66 police officers. The information collected was analyzed using interpretive description. The results showed that participants were motivated to participate in the trial by altruism, and that the participants experienced some concerns about their participation. They stated that altruism in the fight against HIV infection was the main reason for enrolling in the trial. However, young participants were seriously concerned about a possible loss of close relationships if they enrolled in the HIV vaccine trial. Both men and women feared the effect of the trial on their reproductive biology, and they feared interference with pregnancy norms. They were unsure about risks such as the risks of acquiring HIV infection and of suffering physical harm, and they were unsure of the intentions of the researchers conducting the trial. Further, enrolling in the trial required medical examination, and this led some participants to fear that unknown diseases would be revealed. Other participants, however, saw an opportunity to obtain free health services.\ud We have shown that specific fears are important concerns when recruiting volunteers to an HIV vaccine trial. More knowledge is needed to determine participants' views and to ensure that they understand the conduct of the trial and the reasons it is being carried out

Epoxidized natural rubber-toughened polypropylene/organically modified montmorillonite nanocomposites

The objective of this study is to toughen organically modified montmorillonite (OMMT)- filled polypropylene (PP) nanocomposites with epoxidized natural rubber (ENR). PP, ENR (10–20 wt%), OMMT (6 wt%) and maleated PP (PP-g-MA; 10 wt%) were melt blended using counterrotating twin extruder, followed by injection molding to prepare test samples. X-ray diffraction results revealed that the OMMT platelets in PP/OMMT nanocomposites were intercalated and the incorporation of ENR into the nanocomposites further increased the d-spacing of OMMT layers. The Fourier transform infrared spectra showed that the maleic anhydride group in PP-g-MA reacted in situ with the epoxy groups of ENR, which demonstrates the occurrence of grafting reaction. With slight decrease in stiffness and strength, the addition of 20 wt% ENR increased the impact strength of PP/ENR/OMMT nanocomposites by 521% compared to PP/OMMT nanocomposites. Scanning electron microscopy images revealed that the ENR particle size increased with increasing ENR contents in PP/ENR/OMMT nanocomposites. Differential scanning calorimetry results revealed that the presence of ENR and OMMT had slightly increased the crystallization temperature as well as the degree of crystallinity of PP. Thermogravimetric analysis showed that the blending of ENR decreased the thermal stability of PP/OMMT nanocomposites

Review on HVAC system optimization towards energy saving building operation

Works on the optimization of heating, ventilation and air-conditioning (HVAC) systems have been done extensively because of its high amount of building electrical energy usage. This paper provides a review on the optimizations works of HVAC systems based on three main approaches – HVAC operational parameters optimization, HVAC controller parameters optimization and building design parameters optimization. For the system’s operational parameters, the optimization is based on the HVAC’s conventional and predictive energy consumption models which is clear the predictive HVAC system models can get better response to reduce energy consumption compare to conventional energy consumption model. In most works, the thermal comfort model, either indicated by the indoor air quality (IAQ) or the predicted mean vote (PMV) was included. It is be noticed that between IAQ comfort index and PMV comfort index the PMV had a better response that can get 46% reduce the energy consumption. In addition, in the HVAC’s controller optimization approach, its objective is to improve the output response of the HVAC system in order to avoid unnecessary energy usage by optimizing the controller parameters that employ controllers such as Fuzzy Logic, Neural Network and Proportional-Integral-Derivative (PID) controllers. It is clear that among the different controller optimizations mentioned above the fuzzy logic tuning optimization has a better response to reduction of energy consumption rather than other controller optimization approach. Meanwhile, the optimization of building design parameters approach is done before the construction of the buildings so as to reduce the energy consumption, where factors such as HVAC system type, construction material type and window dimensions are determined through the optimization process. This paper reviews the works based on the three approaches of HVAC system optimizations with the objective of reducing energy usage without sacrificing the comfort of occupants inside the building that is recommended to us e predictive HVAC system approaches with fuzzy logic controller. Moreover, comparing different tools for building parameter and design optimization including SEDICAE, EXRETopt and EneryPlus, the EXRETopt by using PMV comfort index makes to 62% reduction of energy consumption