Biodiesel is an alternative fuel produced by chemical reaction between vegetable oil or animal fat with alcohol and catalyst. The preliminary treatment in extraction of biodiesel feedstock is an important process to o...
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Brake lining is one of the components of the braking system on a vehicle that plays an important role for the safety of the driver. Recently, the development of brake lining materials has attracted the attention of ma...
Brake lining is one of the components of the braking system on a vehicle that plays an important role for the safety of the driver. Recently, the development of brake lining materials has attracted the attention of many researchers. At first many brake pads were made of asbestos as the main material, but this brake lining material has begun to be abandoned because it has a negative impact on health and the environment. This paper presents the results of research on the development of a hybrid composite as a brake lining material. This hybrid composite is composed of the main ingredients of basalt and green clam shell waste, as well as a small amount of alumina with phenolic resin as a binder. Hybrid composite brake lining material is made through a sintering process with an emphasis of 2 tons for 30 minutes at a constant temperature of 150°C. Hybrid composite brake pads made 3 variations of weight fraction were tested on a motorcycle to see the performance of deceleration and braking distance. Also tested brake lining with asbestos material as a comparison. The lowest deceleration performance was asbestos brake lining at 6.79 m/s2, while the highest deceleration was HC4 brake lining (35% basalt-15% clam shell) of 11.51 m/s2. While the shortest braking distance is HC4 brake pads (35% basalt-15% shell) of 3.02 meters, while the longest braking distance of asbestos is 15.18 meters. The increase in the percentage of basalt content and the decrease in the percentage of clam shell content indicate a tendency to increase the magnitude of deceleration, and a tendency to decrease the braking distance for each vehicle's initial speed.
Recently, there has been a growing interest in artificial skin on hydrogels as a potential alternative for animal testing to evaluate the efficacy and safety of new drugs or cosmetics. Synthetic polymers have been wid...
Recently, there has been a growing interest in artificial skin on hydrogels as a potential alternative for animal testing to evaluate the efficacy and safety of new drugs or cosmetics. Synthetic polymers have been widely used due to their superior physicochemical properties. However, synthetic polymers such as polyvinyl alcohol (PVA) are limited by their poor biocompatibility and cell adhesion. Combining synthetic and natural polymers can improve these properties. Therefore, in this study, we aimed to investigate the effect of alginate and chitosan addition to PVA-based hydrogels on protein adsorption, cell viability and cell attachment. The addition of chitosan decreased protein adsorption, which was caused by the changes in electrostatic charge by PVA-chitosan interaction and changes in surface roughness. Primary human fibroblast cells cultured on PVA, PVA-alginate and PVA-chitosan had >80% viability which indicates the cytocompatibility of the hydrogels. More importantly, alginate and chitosan also improved the cell attachment on the PVA-based hydrogels. Taken together, the addition of both alginate and chitosan has the potential to improve PVA-based hydrogels for artificial skin application.
Surface and groundwater are important resources for human life and health. Land use changes and mining activities, however, have the potential to compromise the safety of these resources. This study aims to investigat...
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The chemical screening of an algae-containing marine sponge identified as Lendenfeldia species has isolated two 24-homoscalarane sesterterpenoids, including a known compound, felixin A (1) and a new analogue, lendenfe...
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Research on human mental disorders has started exploring the relationship between human facial expression recognition (FER) and symptoms of mental disorders because cases in FER are similar to symptoms in psychiatric ...
Research on human mental disorders has started exploring the relationship between human facial expression recognition (FER) and symptoms of mental disorders because cases in FER are similar to symptoms in psychiatric disease. With the tremendous success of machine learning and deep learning, various models and architecture of these techniques are being leveraged to achieve better performance. The purpose of this work is to undertake a review of the most recent work on automatic facial emotion recognition (FER) using deep learning. We emphasize these contributions from the deep learning architecture and facial databases and the researchers’ progress by comparing the recommended technique with the findings produced. The study found that facial expression recognition based on cognitive internet of things (CIoT) in psychiatry disease did not yet exist, so it became a big opportunity to develop this research in the future. It can be concluded that this research can assist scholars by examining previous works and providing insights to improve this field and can be used as recommendations for psychiatric disease.
This study applies the Integral Transform Method (ITM) to solve the problems caused by dynamic loads that work on structures and its interactions with the soil. The structure and part of the soil from the half space l...
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The Kuranji watershed is one of the watersheds in the city of Padang, which is currently experiencing development due to rapid population growth. This has resulted in land conversion from areas that have vegetation to...
The Kuranji watershed is one of the watersheds in the city of Padang, which is currently experiencing development due to rapid population growth. This has resulted in land conversion from areas that have vegetation to built areas such as settlements. This affects the balance of the Kuranji watershed ecosystem and can lead to geological disasters. Therefore an initial analysis is needed in the development of the Kuranji watershed in the future. This study aims to analyse the interrelation of rainfall and morphometric characteristics that have an impact on geological disasters. The data used are data of maximum rainfall and maximum river discharge in the Kuranji watershed from 2009 - 2018. DEM data (30x30) used to calculate morphometric aspects, consisting of linear aspects, area aspects and relief aspects. The calculation of these aspects is done by a Geographic Information System (GIS) approach using ArcGIS 10.6 software. The result shows that the Kuranji watershed has an area of 22469,55 ha with dendritic drainage patterns. The linear aspect reveals that it has 1894 rivers with a total length of 774,6 km. This aspect explains that with the many tributaries, the Kuranji watershed has the potential to cause flooding. Aspects of the area explain that the Kuranji watershed has an elongated shape, steep slope and causes a rapid and large run-off discharge. Drainage density is at medium level with a value of 3,45 (km/km2) which is close to the high category. The higher the drainage density the smaller the chance of water for infiltration and the greater the river discharge. The relief aspect explains that the Kuranji watershed has a height between 0-1860 meters above sea level. Relief ratio and gradient ratio have a value of 0,08. Gradient ratios with high values result in fast and swift flow of surface and river water flow. This has the potential for landslides, channel erosion and river wall erosion. High rainfall, extreme morphometric characteristics, causes the Kuran
AC-DC power conversion is an essential process in the industrial area at medium/high voltage levels for AC motor drives, conveyor belt systems, rolling mills, or others. The multilevel converters allow us to work at t...
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ISBN:
(纸本)9781665408745
AC-DC power conversion is an essential process in the industrial area at medium/high voltage levels for AC motor drives, conveyor belt systems, rolling mills, or others. The multilevel converters allow us to work at the voltage levels mentioned and give us a low harmonic content in the AC side of the system. However, these power conversion systems consist in their topology of an input transformer, which is sensitive to low order harmonic currents, generating saturation and increased losses. This work proposes a modulation scheme called Feedback Quantizer, applied to multi-cell active front-end rectifiers, aiming to obtain a focused mitigation of low-frequency current harmonics of the power cell. Furthermore, to ensure the stability of the DC voltage of each power cell, a control strategy consisting of nonlinear control, a first-order filter to the DC voltage reference, and a PI control will ensure stability and zero steady-state error at step input. The simulated results show the correct operation of the proposed scheme.
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