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Throughout the history of power systems, power cables have been used to securely and efficiently distribute electrical energy to the destined locations. Cross-linked polyethylene (XLPE), a commonly used insulator in high-voltage cables, have several desirable properties, such as low dielectric loss, high dielectric constant, high thermal conductivity, enhanced thermal stability, and superior resistance against electrical stress. However, further improvements of XLPE's performance are needed. The incorporation of large specific surface area nanoparticles, such as boron nitride nanosheets and graphene oxide, exhibited a great potential in enhancing XLPE's properties. These nanoparticles create numerous trapping sites, even at small loading levels, due to their large interfacial regions. In addition, voltage stabilisers with polar groups can scavenge high-energy electrons generated by local electric fields, thereby inhibiting the electrical tree growth. Another important aspect of enhancing XLPE's dielectric performance is the inclusion of antioxidants with phenolic groups. These antioxidants react with peroxyl radicals, mitigating their harmful effects. This review summarises the effects of nanoparticles, voltage stabilisers, antioxidants, and polymer amalgamation on dielectric performance of XLPE as an insulation material. The major challenges in dielectric insulation such as breakdown voltage strength, electrical tree growth, structural defect, space charge accumulation, and thermal aging are addressed.

Synthetic plastics are severely detrimental to the environment because non-biodegradable plastics do not degrade for hundreds of years. Nowadays, these plastics are very commonly used for food packaging. To overcome this problem, food packaging materials should be substituted with “green” or environmentally friendly materials, normally in the form of natural fiber reinforced biopolymer composites. Thermoplastic starch (TPS), polylactic acid (PLA) and polybutylene succinate (PBS) were chosen for the substitution, because of their availability, biodegradability, and good food contact properties. Plasticizer (glycerol) was used to modify the starch, such as TPS under a heating condition, which improved its processability. TPS films are sensitive to moisture and their mechanical properties are generally not suitable for food packaging if used alone, while PLA and PBS have a low oxygen barrier but good mechanical properties and processability. In general, TPS, PLA, and PBS need to be modified for food packaging requirements. Natural fibers are often incorporated as reinforcements into TPS, PLA, and PBS to overcome their weaknesses. Natural fibers are normally used in the form of fibers, fillers, celluloses, and nanocelluloses, but the focus of this paper is on nanocellulose. Nanocellulose reinforced polymer composites demonstrate an improvement in mechanical, barrier, and thermal properties. The addition of compatibilizer as a coupling agent promotes a fine dispersion of nanocelluloses in polymer. Additionally, nanocellulose and TPS are also mixed with PLA and PBS because they are costly, despite having commendable properties. Starch and natural fibers are utilized as fillers because they are abundant, cheap and biodegradable.

The current study endeavours to examine the learning and comprehension patterns of English aspect categories by Yemeni EFL students in the different levels of undergraduate program at the English department, faculty of arts at Sana'a University. The data of the study were collected from a total of 120 students covering the four levels of undergraduate program. From each level, a group of thirty students were considered. The data on aspectual categories were analysed by using statistical models like one-way analysis of variance ANOVA in SPSS 16.0 and Tukey Post Hoc test. The statistical analysis indicates that (1) there is significant differences in the correct uses of the various English aspect categories across the four levels and (2) errors were not equally distributed within all English aspect categories. (3) the use of Tukey Post Hoc test further suggests that performances at specific levels are significantly different from each other. Furthermore, present perfect tense has received the lowest correct answers across all levels, hence it is considered to be the most problematic among the other categories. The role of Arabic influences has been noticed to be negatively affecting the process of learning and comprehension of aspect categories in the initial years, especially in level one students. Some pedagogical implications have been given.

Introduction: Numerous studies reported that healthcare providers are not as effective in rendering high-quality CPR over time, despite receiving basic life support (BLS) or advanced cardiac life support (ACLS) training. Thus, to overcome the issue and develop a more feasible implementation of CPR training model, this study aims to identify the effectiveness of a modified conventional training (MT-CPR) method. Method: This was an experimental study conducted to 72 healthcare providers in a teaching hospital in north Borneo. Subjects underwent MT-CPR and data were collected using a validated questionnaire and skills assessment checklist adopted from AHA (2020). Data then was analysed using Friedman, Wilcoxon and McNemar test aided with IBM’s Statistical Package for the Social Science (SPSS) statistic software. Result: This study reported that MT-CPR significantly improved the knowledge and skills on CPR (p-value: