Leakage current and surface discharge phenomena : effect on tracking and morphological properties of LLDPE-natural rubber compounds

Polymeric insulators are widely used for high voltage outdoor insulating application due to their substantial advantages compared to the porcelain and glass insulators. Although polymer materials have been proven good, research on development of new polymerbased materials is still on going since the benefits of using polymeric materials are not yet utilised to their full potential. In this work, a new formulated thermoplastic elastomer materials that are composed of linear low-density polyethylene (LLDPE) and natural rubber (NR) filled with different loadings of alumina trihydrate (ATH) fillers is presented. A surface tracking and erosion test is conducted to investigate the characteristics of leakage current on the material surface under the influence of wet contaminated conditions. A computer-based leakage current monitoring system is developed to monitor the leakage current waveform pattern as well as its frequency spectrum. The scanning electron microscope is used to investigate the morphological properties of the materials before and after the tracking test

Anthracnose Disease of Walnut- A Review

Walnut (Juglans regia) an important commercial dry fruit crop, is attacked by several diseases causing economic damage and amongst them walnut anthracnose caused by Marssonina juglandis (Lib.) Magnus has posed a serious threat to this crop in India and abroad. Walnut anthracnose results in reduction in quantitative parameters such as size, mass and actual crop of nuts, failure in metabolic processes in leaves and change in biochemical indices. Premature loss of leaves results in poorly-filled, low-quality, and darkened kernels. The disease initially appears on leaves as brown to black coloured circular to irregularly circular spots. These spots eventually enlarge and coalesce into large necrotic areas. Later on these infected leaves turn yellow and drop prematurely. Infection of anthracnose disease on leaves occurred at relative humidity above 95 per cent and severity of infection was not influenced by temperature between 10-32oC but was significantly reduced below 10oC. Anthracnose of walnut has been reported to be caused by Marssonina juglandis (Lib.) Magnus,with Gnomonia leptostyla (Fr.) Ces. and de Not as its perfect stage reported that acervuli produced by fungus appeared early in the season as small black specks on the lower surface of diseased leaves. The pathogen(G. leptostyla) reportedly perpetuates primarily on infected leaf debris, and ascospores produced in perithecia act as the primary inoculum during spring. Burying (ploughing in) the fallen leaves in autumn and winter ,pruning of infected twigs and branches and adequate nitrogen fertilization has been recommended for the management of walnut anthracnose as well as under planting walnut saplings with annual and perennial legumes has been shown to increase foliage nitrogen content. Different formulations of mancozeb, dithianon, flusilazole and copper fungicides controlled anthracnose disease

Incidence of orbital, conjunctival and lacrimal gland malignant tumors in USA from Surveillance, Epidemiology and End Results, 1973-2009

AIM: To determine the types and incidence of tumors affecting the orbit, conjunctiva and lacrimal glands and to study the trend line of these tumors in the United States from 1973 to 2009. METHODS: We used the publicly available Surveillance, Epidemiology and End Results (SEER) database registries to determine the incidence rates. Age was adjusted to the 2000 US Standard Population. Patients were stratified according to age group, gender, race and histological grouping of tumor lesions. Three age groups were defined: 0-19, 20-49 and ≥50y. Annual percentage changes were calculated to examine trends. RESULTS: The overall age adjusted incidence rate was 3.39 (95%CI: 3.27-3.52) per million person-years. The tumors were more prevalent in age group ≥50 counting 9.51 (95%CI: 9.11-9.92) per million person-years. Most of the soft tissue sarcomas occurred in the young age with incidence rate of 0.35 (95%CI: 0.28-0.42) per million person-years. Lymphomas were the dominant subtype in the adult population with incidence rate of 5.74 (95%CI: 5.43-6.06) per million person-years. Incidence rates were higher in males than females with an overall rate ratio of 1.31 (95%CI: 1.21-1.41) mainly caused by the increase in carcinoma subtypes. White race had a higher tumor incidence with a rate ratio of 1.47(95%CI: 1.25-1.73) driven by the higher incidence of most histological subtypes. Orbital tumors showed a higher incidence rate followed by conjunctival and lacrimal gland tumors with incidence rates of 1.59, 1.37 and 0.43 per million person-years respectively. The trend line of overall incidence of tumors showed a significant increase (APC=3.11, 95%CI: 2.61-3.61) mainly due to increase of lymphomas. This increase was higher than the increase of lymphomas at other sites. CONCLUSION: Orbital, conjunctival and lacrimal gland malignant tumors differ among children and adults. Over the years there has been a noticeable increase in incidence rates of orbital and lacrimal gland tumors mainly caused by an increase in lymphomas and an apparent increase due to advances in diagnostic techniques. ICD-O-3 topographical coding should be improved to consider the different orbital bones and ocular structures

Characterizations of InN Thin Films Grown on Si (110) Substrate by Reactive Sputtering

Indium nitride (InN) thin films were deposited onto Si (110) by reactive sputtering and pure In target at ambient temperature. The effects of the Ar–N2 sputtering gas mixture on the structural properties of the films were investigated by using scanning electron microscope, energy-dispersive X-ray spectroscopy, atomic force microscopy, and X-ray diffraction techniques. The optical properties of InN layers were examined by micro-Raman and Fourier transform infrared (FTIR) reflectance spectroscopy at room temperature. Structural analysis specified nanocrystalline structure with crystal size of 15.87 nm, 16.65 nm, and 41.64nm for InN films grown at N2/Ar ratio of 100/0, 75/25, and 50/50, respectively. The Raman spectra indicates well defined peaks at 578, 583, and 583 cm−1, which correspond to the A1(LO) phonon of the hexagonal InN films grown at gas ratios of 100 : 0, 75 : 25 and 50 : 50 N2 : Ar, respectively. Results of FTIR spectroscopy show the clearly visible TO [E1(TO)] phonon mode of the InN at 479 cm−1 just for film that were deposited at 50 : 50 N2 : Ar. The X-ray diffraction results indicate that the layers consist of InN nanocrystals. The highest intensity of InN (101) peak and the best nanocrystalline InN films can be seen under the deposition condition with N2/Ar gas mixture of 50 : 50

Learning style tendencies based on fleming’s VARK learning style among TVET students

This study aims to identify learning style tendencies based on the Fleming’s VARK learning style of TVET students. This study uses a questionnaire approach to assess TVET students' learning styles based on Fleming’s visual, auditory, writing or reading and kinesthetic learning styles. The study population is technical students of FPTV, UTHM and the selected sample consists of 53 students from various fields namely General Machining (BBA), Welding and Metal Fabrication (BBD), Electrical & Electronics (BBE) and Creative Multimedia (BBF) who took the subject BBD10803 Information Technology in Education at Universiti Tun Hussein Onn Malaysia. The results of this study indicate that the most preferred Fleming’s VARK learning style is a visual learning style

The effect of holmium on microstructure and mechanical properties of light metal alloy

The thesis project investigates the effect of Holmium addition on the microstructure and mechanical properties of cast ZRE1 magnesium alloy. In the advancement of automotive and aerospace industries, the next generation of light metal alloy is magnesium due to its manufacturing abilities and lightweight material. The main limitation of Mg alloys is the ability to improve its mechanical properties. Rare earth elements were used as alloying elements for improving the mechanical properties and producing a new Mg-RE alloy with modified structure and strength. In this studies, it demonstrates the addition of RE at specific amount, which could be considered as main alloy element that may lead to extend limitation of RE application. The amount of Holmium (Ho) at 0.2, 0.4 and 0.6 wt. % were added separately to ZRE1 magnesium alloy. The Optical Microsope, FESEM coupled with EDX, and XRD were used to investigate the microstructure and mechanical properties, including tensile and hardness tests. The results showed that the Ho content at 0.2wt. % increased the ultimate tensile strength and yield strength compared to others Ho composition. Finally, the hardness value was increased and the additive had a significant improvement of mechanical properties, thus the ZRE1 magnesium alloy has been improved with Holmium addition

Polypyrrole thin film sensor base surface plasmon resonance for detection of Cu(II) and Fe(III) in aqueous solution

In this study, the performance of surface plasmon resonance method incorporated with polypyrrole sensing layer was examined for detection of Cu (II) and Fe (III) ions in aqueous solutions. The polypyrrole was prepared by electro-oxidation method on a gold layer for the detecting low concentration ions (0.1, 1 5 10 20 ppm). The experiments carried out at room temperature, and each sample was flowed through the flow cell. A photodiode registered the SPR signals as the function of rotation angle and thickness of layers. For observing the association and dissociation processes, the experiments repeated more than ten times, and the sensorgrams were obtained. Furthermore, Langmuir model was utilized to describe the binding interactions of ions with the polypyrrole layer. The lower concentration detection limit was about 0.1 ppm and the terminal resonance angles were occurred after the 300 s. The sensor was also found to be more sensitive to the presence of Cu than Fe ions

COVID-19 Pandemic: Langkawi Vocational College Student Challenge in Using Google Classroom for Teaching and Learning (T&L)

The implementation of government-issued social awareness during the COVID-19 pandemic has affected the teaching and learning (T&L) activities. This study aims to identify the challenges that students face in using Google Classroom as a T&L method during the COVID-19 pandemic. A total of 39 Culinary Arts Diploma students at Langkawi Vocational College, Kedah who took the subjects of DHA1234 - Basic Food and Cookery, DHA 3051 - Final Year Project 1 and DHA 1123 - Introduction to Hospitality Industry participated in the study. The questionnaire used was adapted from the previous study and had received expert’s confirmation before being used in the study. The results of the study were analyzed using descriptive statistics involving average use, standard deviation, percentage, frequency, and score. Inferencial statistics involved pearson correlation tests. The study showed that the mean level of challenge faced by students in using Google Classroom is 3.46. Meanwhile, the pearson correlation test found that the significant value was .000. Therefore, there was a relationship between motivational and internet networks aspects. Therefore, the hypothesis (H0) stated in the hypothesis section was rejected

An integral equation method for solving neumann problems on simply and multiply connected regions with smooth boundaries

This research presents several new boundary integral equations for the solution of Laplace’s equation with the Neumann boundary condition on both bounded and unbounded multiply connected regions. The integral equations are uniquely solvable Fredholm integral equations of the second kind with the generalized Neumann kernel. The complete discussion of the solvability of the integral equations is also presented. Numerical results obtained show the efficiency of the proposed method when the boundaries of the regions are sufficiently smooth