Sepiolite hybridized commercial fillers,and their effects on curing process,mechanical properties,thermal stability,and flammability of ethylene propylene diene monomer rubber composites

Ethylene propylene diene monomer rubber (EPDM)-based composites containing sepiolite (sep) hybridized with calcium carbonate (CaCO₃), silica (Sil) or carbon black (CB) were prepared on a two-roll mill. The influence of fillers’ contents on the curing, mechanical, thermal and flammability of the composites was investigated. In comparison with EPDM/sep at 30 parts per hundred rubbers (phr) as a control composite, EPDM/sep/CB composites exhibited an outstanding improvement in tensile strength followed by EPDM/sep/Sil and EPDM/sep/CaCO₃ composites. EPDM/sep/CB displayed the highest thermal stability and also improved flammability resistance. In addition, a higher amount of carbon black gave higher tensile strength. The results were influenced by the ability of CB to disperse well and form protective layers acting as mass transport barriers in the matrix. The field emission scanning electron microscopy analyses proved better dispersion of CB in the matrix. The presence of protective layers on the surface of samples consequently improved the thermal properties of the EPDM composites. The mechanism of formation of char protective layer in hybrid EPDM composites was also investigated based on morphological observations of char residues. According to this work, Sil and CB were able to hybrid with sep, while sep could be a potential substitution of CaCO₃ in the EPDM composites.     

Robust and High Accuracy Algorithm for Detection of Pupil Images

Recently, many researchers have tried to develop a robust, fast, and accurate algorithm. This algorithm is for eye-tracking and detecting pupil position in many applications such as head-mounted eye tracking, gaze-based human-computer interaction, medical applications (such as deaf and diabetes patients), and attention analysis. Many real-world conditions challenge the eye appearance, such as illumination, reflections, and occasions. On the other hand, individual differences in eye physiology and other sources of noise, such as contact lenses or make-up. The present work introduces a robust pupil detection algorithm with and higher accuracy than the previous attempts for real-time analytics applications. The proposed circular hough transform with morphing canny edge detection for Pupillometery (CHMCEP) algorithm can detect even the blurred or noisy images by using different filtering methods in the pre-processing or start phase to remove the blur and noise and finally the second filtering process before the circular Hough transform for the center fitting to make sure better accuracy. The performance of the proposed CHMCEP algorithm was tested against recent pupil detection methods. Simulations and results show that the proposed CHMCEP algorithm achieved detection rates of 87.11, 78.54, 58, and 78 according to Świrski, ExCuSe, Else, and labeled pupils in the wild (LPW) data sets, respectively. These results show that the proposed approach performs better than the other pupil detection methods by a large margin by providing exact and robust pupil positions on challenging ordinary eye pictures.     

The impact of computer‐based instruction on the development of EFL learners' writing skills

The current study investigated the application and effectiveness of computer assisted language learning (CALL) in teaching academic writing to Iranian EFL (English as a Foreign Language) learners by means of Microsoft Word Office. To this end, 44 sophomore intermediate university students majoring in English Language and Literature at an Iranian university who had enrolled in a course called Advanced Writing were randomly divided into two groups. As a pre‐test, a pen‐and‐paper writing task was given to both groups at the beginning of the semester. The control group including 24 male and female students was taught based on traditional approach while the experimental group including 20 male and female students was taught based on CALL. At the end of one semester, a pen‐and‐paper writing task was given to both groups. The results of the post‐test revealed that the students who were exposed to computer‐based instruction outperformed their counterparts in terms of using appropriate articles, tense, plural forms and spelling. Moreover, the students in the experimental group produced paragraphs of higher quality. The findings of this study confirmed the efficacy of computer‐based instruction in the development of EFL learners' writing skills.     

The role of transformational leadership as a mediating variable in DeLone and McLean information system success model: The context of online learning usage in Yemen

Governments and higher education institutions around the world are placing online learning in their respective visions and policies as it has already transformed the way in which individuals learn, socialise and do business. Leadership is therefore increasingly playing a major role in the implementation and success of online learning goals. Although researchers have investigated adoption and usage of online learning in different settings, the mediation role of transformational leadership is yet to be examined using the Delone and Mclean IS success model. Data collected from 448 students in nine Yemeni public universities and the subsequent analysis employing structural equation modelling (SEM) via SmartPLS 3.0, revealed five main results: first, overall quality (system, information, and service quality) has a positive impact on transformational leadership; second, transformational leadership has a positive impact on actual usage; third, overall quality has an indirect positive effect on actual usage via transformational leadership; fourth, actual usage significantly affects user satisfaction and performance impact; and fifth, user satisfaction has a positive impact on student performance. The proposed model explains 61% of the variance in performance impact, and theoretical and practical implications are provided as well.