6,751 research outputs found

    Segmented phase of ultraviolet (UV) curable thermoset polyurethanes-graphite (TPU-G) composites

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    Segmented thermoset polymeric materials properties mainly classified through its carbonyl hydrogen bonding. The addition of graphite particle loading in polymeric materials tailored the functional characteristic of the composites. Therefore, the carbonyl hydrogen bonding in the hard segments of the synthesized segmented ultraviolet (UV) curable thermoset polyurethanes-graphite (TPU-G) composites was identified. This composites based green polymer incorporated with varying graphite particles loading were prepared through slip casting method which cure upon UV light. These result in an enhancement of the carbonyl hydrogen bonding which tribute to degree of phase separation (DPS %) in the TPU-G composites ranged from 10-20%, as compared to that in the pure TPU. In addition, the spectroscopy detects the formation of carbonyl hydrogen groups within the TPU-G composites although they are prone to chain scission and undergo photo oxidation subjected to ultraviolet (UV) curing. Upon UV curing, higher graphite weight loading (TPU-G20, TPU-G25 and TPU-G30 composites), shows higher and stable DPS% value, attribute to soft segment- soft segment and hard segment- hard segment establishment. Therefore, the graphite particles dominantly absorb the incident radiation instead of thermoset polyurethane without changing its based

    Availability analysis of terrestrial free space optical (FSO) link using visibility data measured in tropical region

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    Haze and rain are the most impairments factors to free space optical (FSO) links. These weather conditions limit the visibility, and thereby causes high attenuation of the optical signal. This high attenuation reduces the availability performance of the FSO link. This study evaluates the performance of a terrestrial FSO link under tropical climate conditions. The performance analysis is evaluate over 5 km link distance. The cumulative distribution function (CDF) of the received signal to noise ratio (SNR) is used to study the outage performance of the FSO link under haze conditions. The performance analysis is based on three years measured visibility data in Malaysia. Based on the statistical analysis, link availability of 99.99% can be achieved for 37.44 dB SNR over 1 km link distance. Carrier class availability “five nine” can be achieved for 20 dBm transmission power using 1550 nm wavelength

    Green tea polyphenol-reduced graphene oxide: derivatisation, reduction efficiency, reduction mechanism and cytotoxicity

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    This paper reports on the derivatisation, reduction efficiency, reduction mechanism and cytotoxicity of green tea polyphenol-reduced graphene oxide (GTP-RGO). The reduction of graphene oxide (GO) at 90°C using a weight ratio (WR) of GTP/GO=1 resulted in the production of a stable GTP-RGO dispersion in aqueous media, as indicated by the results of ultravioletvisible (UV-Vis) spectroscopy, Fourier transform infrared (FTIR) spectroscopy, thermogravimetric analysis (TGA) and the measurement of zeta potential and electrophoretic mobility. In addition, the results from UV-Vis spectroscopy and X-ray photoelectron spectroscopy (XPS) analysis indicated the comparable reduction ability of GTP relative to the standard reducing agent, hydrazine (N2H4). The removal mechanism of epoxy group from GO via reduction reaction with GTP was investigated by implementing hybrid functional method of Becke-3-parameters-Lee-Yang-Parr (B3LYP)using Gaussian 09 software. The energy and frequency calculations showed that the GO reduction using GTP was more spontaneous and relatively took place faster than the reduction using N2H4, as evidenced by higher entropy change (ΔS) (0.039 kcal/mol·K) and lower Gibbs free energy (ΔG) barrier (58.880 kcal/mol).The cytotoxicities of GO and GTP-RGO samples were evaluated against human colonic fibroblasts cells (CCD-18Co). The GO sample was determined to be toxic even at low concentration (6.25 μg/mL), while the GTP-RGO sample possesses notably low toxicity at the same concentration. The cell culture experiments revealed that the incorporation of GTP led to a decrease in the toxicity of GTP-RGO samples

    Preliminary study of heavy metals pollution in freshwater fishes of Sungai Simpang Empat, Penang. / F. Widad and M. Abdullah

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    A study was conducted to determine heavy metals content in different body parts of fish collected from five sampling stations in Sungai Simpang Empat, Penang from July to December, 2005. The liver, head, gills, muscles and bones of dried fish samples were extracted by the AOAC acid digestion method whilst iron (Fe), zinc (Zn), manganese (Mn), lead (Pb), chromium (Cr), copper (Cu), nickel (Ni) and cadmium (Cd) were analyzed by atomic absorption spectrophotometry. Based on Interim National Water Quality Standard for Malaysia (INWQS), dissolved oxygen, pH, conductivity, ammonia, sulphate, nitrate and phosphate were within the recommended levels suggested for fish to survive except for turbidity levels in some stations, exceeding the recommended of 50 mg/L limit. Fe was accumulated at the highest levels while Cd was the lowest. Only Fe and Mn levels have exceeded the permissible limit of the Malaysian Food Act (1983) and Food Regulations (1985). In most of the fish, liver accumulated the highest concentration of all heavy metals compared to head, gills, muscles and bones. Snakeskin gouramy or Sepat Siam (Trichogaster pectoralis) and black tilapia (Oreochromis mossambicus) are good candidates for potential bioindicator for metals pollution in this study

    Pengaruh Faktor Keperilakuan Organisasi terhadap Implementasi Sistem Akuntansi Keuangan Daerah pada Satuan Kerja Perangkat Daerah Kabupaten Bengkalis

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    This study aims to determine how much influence superiors support, clarity of purpose and training on the implementation of regional financial accounting systems in the work unit of Bengkalis regency. The type of data from this study is quantitative descriptive using primary and secondary data. The data analysis technique used is multiple linear regression. The results of this study are the influence of organizational behavioral factors with a percentage value of 0.677 or 67.7% and the remaining 32.3% is influenced by other variables, namely the Regional Supervision Agency, internal control system, and organizational culture. This research is the latest research in Bengkalis Regency and can be a reference for further research

    Analisis Pengaruh Inflasi dan Pertumbuhan Biaya Produksi terhadap Profit Margin pada Perusahaan Food And Beverages yang Go Publik di Bei

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    The purpose of this research is to know how big influence of Production Cost Inflation and Growth in the companys profit margin than Food and Beverages. Analysis tools used in this study is panel data regression, a combination of two data time series and cross section can provide more data so that it will generate degree of freedom (df) is greater, to determine the effect between inflation and growth in production cost profit margin ratio. Based on the conclusion, it can be concluded that the rate of inflation and growth in production costs affect the level of corporate profit margins at the Food and Beverages during the period 2005-2008 with a coefficient of determination equal to 96.83%. Partially between the inflation rate did not negatively affect the profit margin between the rate of inflation while the growth rate positively affects the production cost. So that can be implicated to obtain a high level of profit margin, then for company management to pay more attention to the level of growth in production costs, such as looking for suppliers who provide raw material prices are much cheaper so that more efficient control of production costs. Keywords: inflation, production cost, profit margi

    Humanoid Localization on Robocup Field using Corner Intersection and Geometric Distance Estimation

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    In the humanoid competition field, identifying landmarks for localizing robots in a dynamic environment is of crucial importance. By convention, state-of-the-art humanoid vision systems rely on poles located outside the middle of the field as an indicator for generating landmarks. However, in compliance with the recent rules of Robocup, the middle pole has been discarded to deliberately provide less prior information for the humanoid vision system to strategize its winning tactics on the field. Previous localization method used middle poles as a landmark. Therefore, robot localization tasks should apply accurate corner and distance detection simultaneously to locate the positions of goalposts. State-of-the-art corner detection algorithms such as the Harris corner and mean projection transformation are excessively sensitive to image noise and suffer from high processing times. Moreover, despite their prevalence in robot motor log and fish-eye lens calibration for humanoid localization, current distance estimation techniques nonetheless remain highly dependent on multiple poles as vision landmarks, apart from being prone to huge localization errors. Thus, we propose a novel localization method consisting of a proposed corner extraction algorithm, namely, the contour intersection algorithm (CIA), and a distance estimation algorithm, namely, analytic geometric estimation (AGE), for efficiently identifying salient goalposts. At first, the proposed CIA algorithm, which is based on linear contour intersection using a projection matrix, is utilized to extract corners of a goalpost after performing an adaptive binarization process. Then, these extracted corner features are fed into our proposed AGE algorithm to estimate the real-word distance using analytic geometry methods. As a result, the proposed localization vision system and the state-of-the-art method obtained approximately 3-4 and 7-23 centimeter estimation errors, respectively. This demonstrates the capability of the proposed localization algorithm to outperform other methods, which renders it more effective in indoor task localization for further actions such as attack or defense strategies

    Student’s reflection on environmental conservation: the level of knowledge, attitude, and behavior

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    The purpose of this paper is to identify the reflection of primary school students’ in term of their environmental conservation awareness based on their knowledge, attitude, and behavior. The survey method was used in data collection and the questionnaire was distributed to 235 students from 25 different school under UTHM’s Knowledge Transfer Program in Kluang District. The results obtained moderate-average level of environmental awareness for each construct (i.e. knowledge, attitude, behaviour). The analysis suggest level of reflection has significant effect on gender and race differences for certain construct, however, it is positive correlation between the level of environmental conservation’s reflection with demographics profile. This study offers new insights into the impact of education on environmental protection, the need for environmental education to improve conservation awareness
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