205 research outputs found
Protection of smart substation based on WLAN complies with IEC61850 using traveling wave analysis
Fast protection of distribution substation based on traveling wave is becoming a reality today. The transient traveling wave is mostly used in protection to determine the faulted line and the fault location. The advantages of signal of traveling wave includes immunity to system oscillation, transition resistance, CT saturation, and neutral point operation modes. In this article, a detailed study for analyzing the performance of using WLAN for real time protection based on the transient traveling wave. The high sampling frequency needed for traveling wave causes blockage in communication in the process bus. Now a packing of multi samples with suitable compression techniques in Merging Unit (MU), or using feature extraction with Hilbert–Huang transform with WLAN compliance with IEC 61850 has been tested. Further, this article presents the modeling and simulation of a WLAN communication network for an automation system using the precepts of IEC 61850, which is currently becoming a trend in Substation Automation System (SAS) specification. This article also investigates the impact of impulsive and interface noise on WLAN performance. Finally, the article advocates the wide application of traveling waves in the digital substations based on the IEC 61850 protocol
Neck, upper back and lower back pain and associated risk factors among primary school children.
Ergonomic among children is important as it will influence their growth, which mainly results from the development of the musculoskeletal system. Their anthropometric characteristics are totally different from adults. A cross-sectional study was conducted on 100 school children from two primary schools in Malaysia. Year 2 and 5 children were randomly selected and were given questionnaires to obtain information on their background, musculoskeletal pain/discomfort complaints, previous skeletal injuries and satisfaction with classroom furniture. A TANITA electronic weighing scale was used to measure their body weights, schoolbag load and relative schoolbag weight. A Harpenden anthropometer was used to measure their standing height. Neck pain (NP) was the most prevalent musculoskeletal disorder (MSD) with lifetime prevalence (LP) of 33% and a periodic prevalence (PP) of 15.3%, followed by the upper back pain (UBP) with a LP of 20.2% and a PP of 9.1% and lastly low back pain (LBP) with a LP of 13.1% and a PP of 8.1%. Binary logistic regression performed, showed the LP of neck pain were significantly influenced by factors namely: overall satisfaction with the classroom furniture, satisfaction with the backrest shape and desk height. Results showed that the schoolbag load and classroom furniture significantly influenced the prevalence of MSD
In-vitro evaluation of the antifungal activities of eel skin mucus from Asian swamp eel (Monopterus albus)
T Discovery and development of new drugs from marine and freshwater animal remain one of the most challenging areas in recent marine sciences field. Thus, the object
of current study to examine the antifungal activity of Asian swamp eel (Monopterus albus) skin mucus. Eel skin mucus aqueous and methanol extracts were prepared
with different extract concentrations from 0.49 to 1000 μg/mL against fungus pathogens i.e. Aspergillus niger and Microsporum gypseum. The antifungal assay conducted
using well diffusion method. The results showed a dose dependent decrease the fungal growth, at 100µl/well, the inhibition zone of methanol extract against M. gypseum
(25.7±0.75) mm, while the aqueous one was (23.3±0.16) mm Whereas eel skin mucus methanol and aqueous extracts showed lower inhibition zone against Aspergillus
niger at the same concentration which was (11.1±0.59) mm and (9.0±0.15) mm respectively. The methanol extract showed the highest inhibitory activity against M.
gypseum because M. gypseum infect the upper layers of the skin and eel skin mucus protect eels from infections. The results were statistically significant with p < 0.001.
In conclusion, the present study carried out to reveal the antifungal activities of eel skin mucus which might be use as a source of antifungal agent
Ergonomics observation: harvesting tasks at oil palm plantation
Objectives: Production agriculture is commonly associated with high prevalence of ergonomic injuries, particularly during intensive manual labor and during harvesting. This paper intends to briefly describe an overview of oil palm plantation management highlighting the ergonomics problem each of the breakdown task analysis. Methods: Although cross-sectional field visits were conducted in the current study, insight into past and present occupational safety and health concerns particularly regarding the ergonomics of oil palm plantations was further exploited. Besides discussion, video recordings were extensively used for ergonomics analysis. Results: The unique commodity of oil palm plantations presents significantly different ergonomics risk factors for fresh fruit bunch (FFB) cutters during different stages of harvesting. Although the ergonomics risk factors remain the same for FFB collectors, the intensity of manual lifting increases significantly with the age of the oil palm trees-weight of FFB. Conclusions: There is urgent need to establish surveillance in order to determine the current prevalence of ergonomic injuries. Thereafter, ergonomics interventions that are holistic and comprehensive should be conducted and evaluated for their efficacy using approaches that are integrated, participatory and cost-effective
Recovery of omega-3 fish oil from Monopterus albus using microwave assisted extraction process
Fish oil are currently high in demand due to its wide range of therapeutic benefits. High content of eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) derived from various sources of marine life in fish oil are essential in human mental developments and metabolism. Swamp Eel Fish, scientifically known as Monopterus Albus is a freshwater fish that highly in demands across South-East Asia and can easily be found in Malaysia. This paper presents the study on the extraction of fish oil from the Monopterus Albus eel fish using microwave assisted extraction (MAE) process with ethanol as a solvent. The yield, acid value and free fatty acid (FFA) content of the Monopterus Albus eel fish oil were studied at different solvent concentrations (0 % v/v-100 % v/v) and solid-to-solvent ratios (0.04 g/ml-0.13 g/ml) with constant time, temperature and power of 30 min, 60 °C and 800 W, respectively. Concentrated Monopterus Albus fish oil was analyzed using 785 DMP Titrino Metrom and scanning electron microscope (SEM). The results showed that the oil yield increases with the increases of solvent concentration and solid-to-solvent ratios with the highest yield of 14.60 % at 100 % v/v and 0.13 g/ml, respectively. Acid values and free fatty acid content recorded was 2.19 mg KOH/g and 1.14 %. Morphology of the before and after extraction process displayed significant structural changes on the surfaces of the sample indicated effectiveness of microwave-assisted extraction in extracting fish oil. The findings from this study suggested the best operating conditions to extracts fish oil from the Monopterus Albus eel fish
Effect of Hydrochloric Acid Concentration on Morphology of Polyaniline Nanofibers Synthesized by Rapid Mixing Polymerization
Polyaniline (PANI) nanofibers with diameters ranging from 60 nm to 190 nm were successfully synthesized by rapid mixing polymerization method at room temperature. The effects of synthesis conditions such as concentration of hydrochloric acid (HCl), ammonium persulfate (APS), and aniline monomer (Ani) on the morphology of PANI nanofibers were investigated using scanning electron microscopy (SEM). FTIR and UV-Vis analysis were performed to characterize the PANI nanofibers. The effect of polymerization time and electrical properties of PANI nanofibers was also discussed. A rapid mixing polymerization method is found to be advantageous in producing bulk quantities of nanofibers
Arthropods-mediated green synthesis of zinc oxide nanoparticles using cellar spider extract: a biocompatible remediation for environmental approach
This study presents an eco-friendly approach to synthesizing zinc oxide nanoparticles (ZnO NPs) using extracts from cellar spiders, addressing environmental and health concerns associated with conventional methods. The spider extract efficiently reduced zinc acetate dihydrate, and the synthesized ZnO NPs underwent comprehensive quantitative characterization, including size, shape, morphology, surface chemistry, thermal stability, and optical properties using Fourier-transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), zeta potential measurements, thermogravimetric analysis (TGA), and UV-vis spectroscopy. The nanoparticles exhibited intended characteristics, and their adsorption capability for methylene blue (MB) was quantitatively assessed using the Freundlich isotherm model and pseudo-second-order kinetic model, providing numerical insights into MB removal efficiency. The study demonstrates the potential of these green-synthesized ZnO NPs for applications in environmental remediation, wastewater treatment, and antibacterial therapies, contributing to both sustainable nanomaterial development and quantitative understanding of their functional properties
Power Transformer Fire and Explosion: Causes and Control
An increasing number of failures of power transformers over the world has led to greater interest in building up much needed expertise in electric power transformers, from its design to both preventive and prescribed maintenance. Winding failure is a frequent cause of transformer failure, bushing failure leads of fire and explosion, but it is still uncertain whether the increasing failure of transformers may be related to increasing lightning activity or increasing electric energy of the transient, surge voltages generated by lightning, especially long continuing currents
and rate of rise of currents. But there are other important causes as well which need close attention, including wearing out of the contact points of tap changers in power generating and substation transformers, and poor maintenance of transformer oil. This paper seeks to review some of the well-known causes that lead to transformer fire and explosion, and highlights the important parts of the power transformer that need careful selection, installation, maintenance and
condition monitoring. Moreover the containment of fires and measures that help to prevent transformer explosions
in case of transformer fires are also discussed.
Keywords: Embedded systems, Smart Antenna; Adaptive Array; Artificial Neural Network
Measurement of nicotine withdrawal symptoms: linguistic validation of the Wisconsin Smoking Withdrawal Scale (WSWS) in Malay
<p>Abstract</p> <p>Background</p> <p>The purpose of the linguistic validation of the Wisconsin Smoking Withdrawal Scale (WSWS) was to produce a translated version in Malay language which was "conceptually equivalent" to the original U.S. English version for use in clinical practice and research.</p> <p>Methods</p> <p>A seven-member translation committee conducted the translation process using the following methodology: production of two independent forward translations; comparison and reconciliation of the translations; backward translation of the first reconciled version; comparison of the original WSWS and the backward version leading to the production of the second reconciled version; pilot testing and review of the translation, and finalization.</p> <p>Results</p> <p>Linguistic and conceptual issues arose during the process of translating the instrument, particularly pertaining to the title, instructions, and some of the items of the scale. In addition, the researchers had to find culturally acceptable equivalents for some terms and idiomatic phrases. Notable among these include expressions such as "irritability", "feeling upbeat", and "nibbling on snacks", which had to be replaced by culturally acceptable expressions. During cognitive debriefing and clinician's review processes, the Malay translated version of WSWS was found to be easily comprehensible, clear, and appropriate for the smoking withdrawal symptoms intended to be measured.</p> <p>Conclusions</p> <p>We applied a rigorous translation method to ensure conceptual equivalence and acceptability of WSWS in Malay prior to its utilization in research and clinical practice. However, to complete the cultural adaptation process, future psychometric validation is planned to be conducted among Malay speakers.</p
Weight changes and lifestyle behaviors in women after breast cancer diagnosis: a cross-sectional study
Background: Weight gain rather than weight loss often occurs after breast cancer diagnosis despite breast cancer survivors frequently reported making healthful lifestyle changes. This study describes the prevalence and magnitude of changes in weight before and after breast cancer diagnosis and examines lifestyle behaviors of breast cancer survivors with stable weight, weight gain or weight loss. Methods. Respondents were 368 women with breast cancer characterized by stages I, II and III. All were recruited from hospitals or breast cancer support groups and had completed conventional treatment. Current weight and height were measured while weight at cancer diagnosis and 1 year before diagnosis were self-reported. Weight change was calculated as the difference between current weight and weight a year preceding breast cancer diagnosis. A 24-hour diet recall and Global Physical Activity Questionnaire assessed dietary intake and physical activity, respectively. Differences in lifestyle behaviors among weight change groups were examined using Analysis of Covariance (ANCOVA). Results: Mean weight change from a year preceding diagnosis to study entry was 2.73 kg (95% CI: 1.90-3.55). Most women (63.3%) experienced weight gain rather than weight loss (36.7%) with a higher percentage (47.8%) having at least 5% weight gain (47.8%) rather than weight loss (22%), respectively. Compared to other weight change groups, women in >10% weight gain group had the lowest fruit and vegetable servings (1.58 servings/day; 95% CI: 1.36-1.82) and highest servings of dairy products (0.41 servings/day; 95% CI: 0.30-0.52). Conclusions: Weight gain was evident in this sample of women after breast cancer diagnosis. Information on magnitude of weight change after breast cancer diagnosis and lifestyle behaviors of breast cancer survivors with varying degrees of weight change could facilitate the development and targeting of effective intervention strategies to achieve healthy weight and optimal health for better survival
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