Radio sources are very weak since this object travel very far from outer space. Radio astronomy studies are limited due to radio frequency interference (RFI) that is made by man. If the harassment is ...not stopped, it will provide critical problems in their radio astronomy scientists research. The purpose of this study is to provide RFI map Peninsular Malaysia with a minimum mapping techniques RFI interference. RFI mapping technique using GIS is proposed as a tool in mapping techniques. Decision-making process for the selection requires gathering information from a variety of parameters. These factors affecting the selection process are also taken account. In this study, various factors or parameters involved such as availability of telecommunications transmission (including radio and television), rainfall, water line and human activity. This study will benefit radio astronomy research especially in the RFI profile in Malaysia. Keywords: Radio Astronomy, Radio Frequency Interference (RFI), RFI mapping technique : GIS.
Solar radio burst is a signature of solar flare generated by plasma emission mechanism. Radio burst is a diagnostic tool to study electron beam evolution and plasma background properties in corona ...and interplanetary medium. Sudden release magnetic energy up to 1032 ergs due to magnetic connection accelerates electron located at accelerated site to propagate near relativistic. This fast group of electron propagating through plasma background induced high level of Langmuir wave due to bump in tail instability. Non linear wave-wave causing radio burst near the local plasma frequency. In this paper, frequency drift of radio burst is calculated only from 1 MHz to 400 kHz and the data is obtained from Coordinated Data Analysis Web (CDAweb). The data is analysed by identifying time during maximum intensity of burst at the particular frequency range. Only 45 burst observed in September 2017 is considered in this paper. Meanwhile the data of solar wind speed and density is collected from Advanced Composition Explorer (ACE) satellite. Drift frequency of burst then compared to average of solar wind and density. From the analysis, drift frequency of burst decreasing against solar wind speed and solar wind density. But both relationship shows very weak correlation between drift frequency and solar wind properties.
Abstract Background aims Suspension mononuclear cells (MNCs) can be differentiated into osteoblasts with the induction of ascorbic acid and β-glycerophosphate. The aim of this study was to determine ...the ability of suspension MNCs to differentiate into osteoblasts using ascorbic acid only. Methods Suspension MNCs were obtained by a combination of gradient centrifugation and culture selection. Suspension MNCs were subjected to differentiation assay by culturing them inside proliferation medium supplemented with 10 μg/mL, 30 μg/mL, 50 μg/mL, 60 μg/mL, 90 μg/mL and 500 μg/mL of ascorbic acid. Proliferation medium supplemented with 50 μg/mL ascorbic acid and 10 mmol/L β-glycerophosphate was used as a positive control for osteoblast induction, and proliferation medium without ascorbic acid was used as a negative control. Differentiation analysis was performed using alkaline phosphatase (ALP) assay, von Kossa staining and expression of osteoblast-related genes. Results With all concentrations of ascorbic acid used, there was a significant increase ( P < 0.05) in ALP-specific activity and mineralized nodule formation throughout the differentiation course compared with negative control. Ascorbic acid was also able to activate the expression of osteopontin ( SPP1 ), osteonectin ( SPARC ) and runt-related transcription factor 2 ( RUNX2 ) messenger RNA in positive control and ascorbic acid-induced MNCs (30 μg/mL and 90 μg/mL) but not in negative control. Conclusions Ascorbic acid alone was sufficient to induce osteoblast differentiation from suspension MNCs; 30–90 μg/mL of ascorbic acid was found to be the optimal concentration. Ascorbic acid can be used as a nutritional supplement for cellular therapy of bone-related disease.
Usage of waste materials as concrete mixture can reduce the waste management crisis in the world. Used tyres were widely researched as an alternative source of aggregates replacement in concrete ...mixture. This research is to study the behaviour of concrete incorporating rubber tyre crumb as fine aggregate replacement. The workability, compression strength and water absorption of this concrete will be determined and then compared to normal concrete. Motorcycle inner tube will be used as rubber source and it will be shredded to crumbs. Three samples of concrete with rubber as fine aggregates were prepared. Rubber crumbs will be used to replace fine aggregates in 2.5, 5.0 and 7.5% in mass. Normal concrete were prepared separately as control for comparison. Concrete mixture of 1:2:4 and 0.5 of water cement ratio were used. Slump test were done to test the workability of each mix. Twelve sample cubes from (150mm x 150mm x 150mm) each mix were prepared and cured for 7, 14 and 28 days. Compression tests were performed for each mix cube at age 7, 14 and 28 days. Water absorption test were done at age 28 days. Results revealed that rubberized concrete has better workability than normal concrete. They also have smaller compressive value and higher water absorption compared to normal concrete.
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