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"Organic photovoltaic (OPV) devices have lower efficiency, shorter lifetimes, faster degradation, and poorer stability thaninorganic photovoltaics (IPV) in ambient conditions. In this paper, the equivalent electrical circuit of a two-diode modeleffectively extracts the model-fit electrical photovoltaic (PV) parameters from degraded OPV devices, especially theseries (Rs) and shunt (Rsh) resistances. The result shows a better correlation between the resistances of the devices andperformance of the devices over the degradation process where the devices are deliberately exposed to ambient conditionsunder constant illumination. The degradation of the devices is mostly caused by the degradation of the aluminum (Al)electrode from water and oxygen, which correlates to the Rs. However, it is possible that the degradation of the bulk activelayer can also occur due to the constant illumination on the device, which causes a reduction of photocurrent.Aplikasi Model Rangkaian Setara untuk Memantau Degradasi Sel Fotovoltaik Organik. Divais fotovoltaik organik(OPV) memiliki efisiensi yang lebih rendah, masa hidup lebih pendek, degradasi lebih cepat, dan stabilitas lebih rendahdari photovoltaics anorganik (IPV) pada kondisi udara terbuka. Pada tulisan ini, rangkaian setara dari model dua-diodasecara efektif mengekstrak parameter-parameter listrik fotovoltaik (PV) dari divais OPV yang terdegradasi, khususnyaresistansi seri (Rs) dan resistansi paralel (Rsh). Hasilnya menunjukkan suatu korelasi yang lebih baik antara resistansidivais dan kinerja divais selama proses degradasi dimana divais diberi pencahayaan konstan pada kondisi udara terbuka.Degradasi divais ini sebagian besar disebabkan oleh degradasi elektroda aluminium (Al) yakni oleh air dan oksigen, yangberkorelasi dengan Rs. Namun, ada kemungkinan bahwa degradasi lapisan aktif juga dapat terjadi karena pencahayaankonstan pada divais, yang menyebabkan pengurangan photocurrent."

"Aplikasi Model Rangkaian Setara untuk Memantau Degradasi Sel Fotovoltaik Organik. Divais fotovoltaik organik (OPV) memiliki efisiensi yang lebih rendah, masa hidup lebih pendek, degradasi lebih cepat, dan stabilitas lebih rendah dari photovoltaics anorganik (IPV) pada kondisi udara terbuka. Pada tulisan ini, rangkaian setara dari model dua-dioda secara efektif mengekstrak parameter-parameter listrik fotovoltaik (PV) dari divais OPV yang terdegradasi, khususnya resistansi seri (Rs) dan resistansi paralel (Rsh). Hasilnya menunjukkan suatu korelasi yang lebih baik antara resistansi divais dan kinerja divais selama proses degradasi dimana divais diberi pencahayaan konstan pada kondisi udara terbuka. Degradasi divais ini sebagian besar disebabkan oleh degradasi elektroda aluminium (Al) yakni oleh air dan oksigen, yang berkorelasi dengan Rs. Namun, ada kemungkinan bahwa degradasi lapisan aktif juga dapat terjadi karena pencahayaan konstan pada divais, yang menyebabkan pengurangan photocurrent.

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Organic photovoltaic (OPV) devices have lower efficiency, shorter lifetimes, faster degradation, and poorer stability than inorganic photovoltaics (IPV) in ambient conditions. In this paper, the equivalent electrical circuit of a two-diode model effectively extracts the model-fit electrical photovoltaic (PV) parameters from degraded OPV devices, especially the series (Rs) and shunt (Rsh) resistances. The result shows a better correlation between the resistances of the devices and performance of the devices over the degradation process where the devices are deliberately exposed to ambient conditions under constant illumination. The degradation of the devices is mostly caused by the degradation of the aluminum (Al) electrode from water and oxygen, which correlates to the Rs. However, it is possible that the degradation of the bulk active layer can also occur due to the constant illumination on the device, which causes a reduction of photocurrent."

"Biofilm is an aggregate of consortium bacteria that adhere to each other on a surface. It is usually protected by the exopolysaccharide layer. Various invasive medical procedures, such as catheterization, endotracheal tube installation, and contact lens utilization, are vulnerable to biofilm infection. The National Institute of Health (NIH) estimates 65% of all microbial infections are caused by biofilm. Periplasmic α-amylase (MalS) is an enzyme that hydrolyzes α-1, 4- glicosidic bond in glycogen, starch, and others related polysaccharides in periplasmic space. Another protein called hemolysin-α (HlyA) is a secretion signal protein on C terminal of particular peptide in gram negative bacteria. We proposed a novel recombinant plasmid expressing α-amylase and hemolysin-α fusion in pSB1C3 which is cloned into E.coli to enable α-amylase excretion to extracellular for degrading biofilm polysaccharides content, as in starch agar. Microtiter assay was performed to analyze the reduction percentage of biofilm by adding recombinant E.coli into media. This system is more effective in degrading biofilm from gram positive bacteria i.e.: Bacillus substilis (30.21%) and Staphylococcus aureus (24.20%), and less effective degrading biofilm of gram negative i.e.: Vibrio cholera (5.30%), Pseudomonas aeruginosa (8.50%), Klebsiella pneumonia (6.75%) and E. coli (-0.6%). Gram positive bacteria have a thick layer of peptidoglycan, causing the enzyme to work more effectively in degrading polysaccharides."

"Many applications and industrial processes require very low cooling temperature, such as cold storage in the biomedicalfield, requiring temperature below -80 °C. However, single-cycle refrigeration systems can only achieve the effectivecooling temperature of -40 °C and, also, the performance of the cycle will decrease drastically for cooling temperatureslower than -35°C. Currently, most of cascade refrigeration systems use refrigerants that have ozone depletion potential(ODP) and global warming potential (GWP), therefore, in this study, a cascade system is simulated using a mixture ofenvironmentally friendly refrigerants, namely, carbon dioxide and a hydrocarbon (propane, ethane or ethylene) as therefrigerant of the low temperature circuit. A thermodynamic analysis is performed to determine the optimal compositionof the mixture of carbon dioxide and hydrocarbons in the scope of certain operating parameters. In addition, aneconomic analysis was also performed to determine the annual cost to be incurred from the cascade refrigeration system.The multi-objective/thermoeconomic optimization points out optimal operating parameter values of the system, toaddressing both exergy efficiency and its relation to the costs to be incurred."

"Magnesium merupakan kandidat material yang banyak dikembangkan untuk aplikasi implan tulang yang mampu luruh. Pada penelitian ini dikembangkan paduan Mg-1,6Gd dengan diberikan perlakuan canai hangat menyilang dan searah dengan reduksi ketebalan masing-masing 30% dan dilihat pengaruhnya terhadap laju degradasi. Mg-1,6Gd dilakukan pre-heating selama 5 jam pada temperatur 550°C lalu dilakukan proses pencanaian. Empat buah sampel untuk masing-masing metode dilakukan canai dengan variasi temperatur yang berbeda. Laju degradasi diukur dalam larutan Ringer Laktat dan larutan Kokubo Simulated Body Fluid (SBF) masing-masing dengan metode polarisasi dan imersi. Proses pencanaian menyilang lebih efektif menurunkan laju degradasi Mg-1,6Gd dibandingkan proses pencanaian menyarah. Hal ini disebabkan karena mikrostruktur yang dihasilkan dari proses pencanaian menyilang cenderung lebih homogen. Hubungan temperatur pencanaian dengan laju degradasi menunjukkan hasil yang fluktuatif akan tetapi memiliki kecenderungan laju degradasi yang lebih tinggi seiring dengan peningkatan temperatur. Pengujian dalam larutan Kokubo SBF menunjukkan laju degradasi yang lebih rendah dibandingkan dalam larutan Ringer Laktat. Pada larutan Ringer Laktat laju degradasi paling rendah dicapai pada sampel menyilang berkode D yaitu 1,321 mm/yr. Sementara itu, pada larutan Kokubo SBF laju degradasi paling rendah dicapai pada sampel canai menyilang berkode C dengan laju degradasi mencapai 0,724 mm/yr.

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Magnesium has been developed as a strong candidate material for biodegradable bone implant. In this study, Mg-1,6Gd is warm rolled with two different method, cross rolling and single pass-rolling each being reduced into 30% thickness and the influence into its corrosion behavior was observed. Mg-1,6Gd was preheatead at 550oC in 5 hours before rolling. Four samples for each method was rolled at different temperature. Degradation rate was measured in Ringer Lactate solution and Kokubo SBF by polarization and immersion test.

The result shows that cross roll method was more effective than single pass roll method in decreasing degradation rate of Mg-1,6Gd. The reason is microstructure of cross roll method is more homogenous than single pass method. The effect of rolling temperature is quite fluctuative but show a positive trend to degradation rate.

Measurement of degradation rate in Kokubo SBF shows lower value than in Ringer Lactate Solution. The lowest degradation rate in Ringer Lactate solution is achieved by cross-rolled sample "D" with degradation rate 1.321 mm/yr. For Kokubo SBF the lowest degradation rate is achieved by cross-rolled sample "C" with degradation rate 0,724 mm/yr."

"Variabel-variabel proses canai panas dapat ditentukan sedemikian rupa untuk memproduksi baja paduan dengan ukuran butir ferritdan sifat mekanis yang spesifik. Penelitian ini bertujuan untuk mengembangkan model ukuran butir ferrit akhir baja HSLA 0,028% Nb berdasarkan variabel-variabel operasional canai panas serta model kekerasan Vickers berdasarkan ukuran butir ferrit akhir.Hasilnya adalah bahwa ukuran butir ferrit akhir dapat diprediksi dari ukuran butir austenit semula, regangan, laju regangan, temperatur canai, dan laju pendinginan. Didapatkan juga bahwa kekerasan Vickers dapat diprediksi dari ukuran butir ferrit akhir, regangan, laju regangan, dan temperatur canai.

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Hot rolling variables can be determined as such to produce alloy steels having specific ferrite grain size and mechanical properties. The aim of this research is to develop model of ferrite grain size of 0,028%-Nb HSLA steel based on hot rolling operational variables and model of Vickers hardness based on the final ferrite grain size.

Results show that ferrite grain size can be predicted based on the initial austenite grain size, strain, strain rate, rolling temperature, and cooling rate. It is also found that Vickers hardness can be predicted based on the final ferrite grain size, strain, strain rate, and rolling temperature."

"Telah dilakukan pembuatan perangkat lunak portal monitor radiasi dengan menggunakan LabVIEWTM. Perangkat lunak ini mampu mendeteksi adanya sumber radiasi standard di dalam model kendaraan. Pada saat model melewati portal radiasi (PMR) akan terjadi alarm karena hasil cacahan melebihi ambang batas yang sudah ditetapkan. Semua alarm yang terjadi, data pemindaan, data latar dan kendaraan disimpan dalam database. Dari sepuluh kali percobaan PMR, adanya sumber pada model kendaraan tersebut selalu dapat dikenali. Bentuk profil hasil hasil pemindaian belum dapat menunjukkan letak sumber di dalam model kendaraan."