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Fithriyah N.H.,Muhammadiyah University of Jakarta | Erdawati,State University of Jakarta
Journal of Engineering Science and Technology

An environmentally friendly process were employed to prepare samples of recycled paper, as well as the coating solution of chitosan nanoparticles and dispersion of Ca(OH)2 particles. The nanomaterial was tested for antibacterial and acidity neutralising functions to preserve the strength and colour of paper samples. The paper samples were then characterised for physical and morphological characteristics, as well as chemical and mechanical properties. At concentrations of 0.125 and 0.25 mg/L, the chitosan nanoparticles (23-62 nm) were observed to retard the propagation of E. Coli and S. Aureus bacteria up to 22 and 26 mm in diameter, respectively. This propagation was also hindered by an increase in acidity introduced by Ca(OH)2 nanoparticles. The grammage, firmness, and colour of coated paper samples were not significantly influenced by nanoparticles concentration or coating thickness due to the low mass-to-area ratio of coating. Nevertheless, the tear strengths and cracking resistance of coated paper were improved. Chitosan nanoparticles in the coating potentially functioned as a sizing agent by diffusing into the pores of paper fibres and increasing the interfibrillar bonding, while the nanoparticles of Ca(OH)2 apparently preserved the strength and colour of paper samples by neutralising the acidity and thus preventing microbiological attacks. © School of Engineering, Taylor’s University. Source

Sjaiful Alim E.,Muhammadiyah University of Jakarta
Workshop Proceedings of the 20th International Conference on Computers in Education, ICCE 2012

This paper is a research report concerning Computer-Assisted Language Learning (CALL), used as medium of teaching English; in terms of looking for significant correlation between the Students' attitude towards ICT with the students' learning achievements in English. This is a kind of experimental research; where the data processing was performed by using descriptive statistics that aimed to know; the mean, the median, the range, the standard deviation, the variance, the minimum and the maximum score, and the presentation of the data forms to show the frequency of distribution and in a histogram. Based on the calculation of the correlation score, the research variables have positive correlation and it can be said that there is quite strong and significant correlation with the significance level of 5% (Sig. < 0.05). It means that all the three hypotheses stated or presented in this study could be accepted. Source

Hendrawati T.Y.,Muhammadiyah University of Jakarta
Journal of Engineering Science and Technology

Aloe vera powder was produced from gel of Aloe Chinensis Baker from Pontianak, Indonesia. The effect of drying air inlet temperature to produce Aloe vera powder from Aloe Chinensis Baker was studied. Gel of Aloe Chinensis Baker was crushed, evaporated, mixed with maltodextrin and dried in a Shimadzu counter current spray dryer.Dryingair inlettemperature in spray dryer was varied110°C, 120°C, 130°C and 140°C. The raw material was analysed such as proximate, amino acid, calcium, magnesium, phosphor, lead, sodium, potassium and mangan. The product, Aloe vera powder was analysed such as appearance, colour, water content, pH, density, microbiology and the result was compared with Aloe vera powered commercial from Terry Labs. The active compounds on Aloe vera powder was analysed using LC-MS. InLC-MSdetectedcompoundsin the form especiallyionsM+H, sothere areadditionalmolecules intoionsin theM+1.This method was applied to determine five compounds in evaporated Aloe vera gel, Aloe vera powder (with drying inlet air temperature 110°C, 120°C, 130°C, 1400C). Aloin A and B, aloenin (B), aloesin and chrysophanol could be detected in all of samples. Aloe-emodin could not be detected in all samples. Aloeresin A could be detected in evaporatedAloevera gel, Aloe vera powder (with drying inlet air temperature 110°C, 120°C). The result was shown that the optimum air drying air inlet temperature was 1200C to produce Aloe vera powder which all of phenolic compounds of Aloe verapowder can still be maintained.Some of quality parameters such as water content, pH, solubility, colour, appearance, and microbiology are compliance with the standard of available commercial product. © School of Engineering, Taylor’s University. Source

Endrini S.,YARSI University | Jaksa S.,Muhammadiyah University of Jakarta | Marsiati H.,YARSI University | Othman F.,University Putra Malaysia | Rahmat A.,University Putra Malaysia
Journal of Medicinal Plants Research

The cola nut (Cola nitida) tree is native to West Africa. It has been naturalized to South America, Central America, the West Indies, Sri Lanka, and Malaysia. Related to cocoa, cola nut is the source of a stimulant, and contains the polyphenolic compounds (including catechin, epicatechin, tannins, and 'Kola red') and the methylxanthine alkaloids that also occur in coffee, cocoa, and tea. Previous study has been shown the potential anticarcinogenic effect of cola nut extract on human breast cancer cell lines, MCF-7.This study was conducted to determine their mechanism of action through the apoptotic cell approach. The effect of cola nut extract on the apoptotic cell of MCF7 cells was determined by flow cytometric analysis. MCF7 cells were treated with 60 and 80 μg/ml of cola nut extract for 24 h and subjected to FACS analysis. MCF7 cells treated with 60 μg/ml cola nut extract showed an increase of 6.55% in population of apoptotic cells with a concomitant decrease in the percentage of cells in the S and G2/M phase of cell cycle compared to DMSO-treated control cells. Similarly, MCF7 cells treated with 80 μg/ml cola nut extract showed an increase of 8.29% in population of apoptotic cells with a concomitant decrease in the percentage of cells in the S and G2/M phase of cell cycle compared to DMSO-treated control cells. This suggests that cola nut treatment induces apoptosis at 24 h. In conclusion, cola nut extract may induce apoptosis in MCF-7 cell lines. © 2011 Academic Journals. Source

Gunawan R.,University of Indonesia | Yusivar F.,University of Indonesia | Yan B.,Muhammadiyah University of Jakarta
Journal of Theoretical and Applied Information Technology

The Self Excitated Induction Generator (SEIG) is very popular now as a generated alternating power. In this research the induction machine is approached in the physically and mathematically approximated which then transformed from three-phase frame abc to two-axis frame dq using the Park and Clark transformation. Based on the reactive power demand and capacitor mounted on the stator of the induction machine then do the physical and mathematical approach of the system to obtain a state space model. Under known relationships, magnetization reactance and magnetizing current is not linear, so do mathematical approach to the magnetization reactance and magnetization currents characteristic curve to obtain the magnetic reactance equation used in the calculation. Obtained state space model and the magnetic reactance equation is simulated by using Runge Kutta method of fourth order in the exponent equation with correction factor. The influence of the stator current in q axis iqs, is very strong and the equation of this current is non power-invariant then, using take the stator current reference iqs refis (2/3) Ibase. The correction factor K4has done the magnetizing inductance Lmand also the output terminal voltage of SEIG more precision than before. © 2005 - 2015 JATIT & LLS. All rights reserved. Source

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