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"Dimethyl ether (DME) is a type of renewable energy that could replace the use of fossil fuel in Indonesia. Nevertheless, DME can cause degradation of rubber-based materials. Therefore, the performance of rubber that has been degraded by DME must be improved. This research study aims are to determine the degradation characteristics of modified vulcanized natural rubber in a DME environment. The effect of the filler (carbon black) and plasticizer (minarex-B) components of vulcanized natural rubber was examined. The vulcanized rubber samples were comprised of 10, 30, and 60 parts per hundred rubbers (phr) of filler and 0, 10 and 20 phr of plasticizer. The degradation of the mass and mechanical properties of the rubber were investigated. Degradation testing was conducted by immersing the samples inside a pressure vessel that was filled with the liquid phase of DME. The results indicate that the increasing of the filler composition reduces the impact of degradation, while the increasing of the plasticizer composition has the opposite effect. The plasticizer is needed to distribute the filler to all parts of the rubber. Consequently, a filler composition of 30 phr and a plasticizer composition of 10 phr provide a vulcanized natural rubber with optional protection against the degradation caused by DME. The characteristics of natural rubber, as measured by Fourier Transform Infra-Red Spectroscopy (FTIR) proved that DME does not damage the structure of the polymer chains, although DME may react with some ingredients in the rubber that have a similar polarity."

"Dimethyl ether (DME) is a type of renewable energy that could replace the use of fossil fuel in Indonesia. Nevertheless, DME can cause degradation of rubber-based materials. Therefore, the performance of rubber that has been degraded by DME must be improved. This research study aims are to determine the degradation characteristics of modified vulcanized natural rubber in a DME environment. The effect of the filler (carbon black) and plasticizer (minarex-B) components of vulcanized natural rubber was examined. The vulcanized rubber samples were comprised of 10, 30, and 60 parts per hundred rubbers (phr) of filler and 0, 10 and 20 phr of plasticizer. The degradation of the mass and mechanical properties of the rubber were investigated. Degradation testing was conducted by immersing the samples inside a pressure vessel that was filled with the liquid phase of DME. The results indicate that the increasing of the filler composition reduces the impact of degradation, while the increasing of the plasticizer composition has the opposite effect. The plasticizer is needed to distribute the filler to all parts of the rubber. Consequently, a filler composition of 30 phr and a plasticizer composition of 10 phr provide a vulcanized natural rubber with optional protection against the degradation caused by DME. The characteristics of natural rubber, as measured by Fourier Transform Infra-Red Spectroscopy (FTIR) proved that DME does not damage the structure of the polymer chains, although DME may react with some ingredients in the rubber that have a similar polarity."

"ABSTRAKDimetil eter (DME) adalah salah satu bahan bakar alternatif terbarukan yang dapat menggantikan pemakaian energi fosil di Indonesia. Penggunaan senyawa ini menghasilkan pembakaran yang efisien serta ramah lingkungan. Akan tetapi, dimetil eter diketahui menyebabkan degradasi pada material karet, yang banyak digunakan sebagai sealant ataupun selang pada tempat penyimpanan bahan bakar dari mesin pembakaran. Hingga penelitian ini, setiap jenis material karet mengalami degradasi yang berbeda-beda sehubungan dengan senyawa ini. Oleh karena itu, penelitian ini utamanya ditujukan untuk menentukan jenis degradasi material karet, khususnya karet alam vulkanisat, terhadap dimetil eter. Selain itu, penelitian ini hendak melihat pengaruh komposisi filler dan petroleum oil dari karet alam vulkanisat terhadap degradasi tersebut. Eksperimen yang dilaksanakan mencakup: sintesis, uji degradasi, karakterisasi mekanis dan morfologi. Nilai komposisi filler yang dipakai untuk sintesis yaitu: 10, 30, dan 60 phr; sedangkan nilai komposisi petroleum oil yang dipakai adalah 0, 10, dan 20 phr. Uji degradasi karet alam vulkanisat dilakukan dengan merendam seluruh sampel dalam pressure vessel yang berisi dimetil eter cair, yang diperoleh dari proses pencairan fasa gasnya. Karakterisasi mekanis yang dilakukan mencakup: % perubahan massa, kekuatan tensile, elongasi maksimum, dan kekerasan. Karakterisasi morofologinya berupa pengamatan langsung dan scanning electron microscopy (SEM). Data-data karakterisasi tersebut menunjukkan bahwa karet alam vulkanisat mengalami degradasi jenis absorpsi dan ekstraksi oleh karena dimetil eter. Adapun penambahan komposisi filler ditemukan dapat mengurangi pengaruh degradasi, sedangkan penambahan komposisi petroleum oil justru memperparah degradasi. Namun demikian, petroleum oil juga dibutuhkan karena dapat membuat distribusi filler merata pada seluruh bagian karet alam vulkanisat. Maka dari itu, dengan meninjau keseluruhan data tersebut, didapatkan bahwa komposisi filler dan petroleum oil yang memberikan perlindungan paling optimal terhadap degradasi oleh dimetil eter masing-masing bernilai 30 phr dan 10 phr.

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ABSTRACTDimethyl ether (DME) is one of the renewable energy that could replace the usage of fossil fuel in Indonesia. The usage of this compound could produce efficient and environmental-friendly combustion. However, based on previous research, dimethyl ether is found to cause degradation on rubber-based materials, which are used as sealant or hose inside the fuel tanker of combustion engines. Until this research, it is found that each types of rubber has suffered different kinds of degradation that caused by dimethyl ether. Therefore, the main goal of this research is to determine what kind of degradation will happen on rubber, especially vulcanized natural rubber, that cause by dimethyl ether. Moreover, this research is going to see the effect of filler and petroleum oil composition contained in vulcanized natural rubber against that degradation. There are three parts of experiments will conducted: synthesis, degradation testing, mechanical and morphology characterization. The variation value of filler composition used are 10, 30, and 60 phr; while the variation value of petroleum oil composition are 0, 10, and 20 phr. Degradation testing is done by immersing all samples inside pressure vessel that have been filled with liquid dimethyl ether, which produced from its gas by liquefaction process. Mechanical characterization that observed includes: % change of mass, tensile strength, maximum elongation, and hardness. On the other side, morphology characterization is done by direct observation and scanning electron microscopy (SEM). Those datas reveals that vulcanized natural rubber suffer absorption and extraction, two types of degradation, because of dimethyl ether. Increasing of filler composition could reduce the impact of degradation, while increasing of petroleum oil composition will give the opposite results. However, it is also found that petroleum still must needed to make distribution of filler goes through all parts of rubber. Therefore, based on these datas, we get that 30 phr of filler and 10 phr of petroleum pil will give the optimal protection on vulcanized natural rubber against degradation caused by dimethyl ether."

"Ballast is one of themain structures for the railway tracks. It can resist the lateral movementunder dynamic loading transferred by the passing trains with repeatedly. Undersome circumstances, ballast can suffer degradation or breakdown due to therepeated loading and maintenance. Ballast is easily exposed to the weatherbecause it is laid on the track. Acid rain affects the performance of therailway track near the industrial and urbanarea. As a result, it starts to foul and the small chips from ballast filledthe void, as well as reduce the shear strength of ballast particles. Thissituation can contribute into the increasing of maintenance frequency andcosting. This paper examines the potential of rubber inclusions in increasingthe shear resistance of rubber-ballast composites in simulated water and acid soakedconditions with several configuration. This lab-based exploratory work is only static load simulation in conventional shear boxsetup measuring 60 mm × 60 mm.The aggregates size is 10 times smaller than actual size of ballast. In orderto identify the shear resistance deterioration of rubber-aggregates mixtureunder poor drainage conditions by soaked a batch of aggregates in water andacid solution for 2 weeks to simulate accelerated weathering effects. The shearresistance did not rise dramatically with the rubber reinforcement. Thissusceptible shear strain plots indicate ductile behaviour on theaggregates-rubber composites. This is evident by the linear rise of shearstress with strain up to approximately 10% for the control samples (CS) untilit reaches a constant value. Note that all the specimens including CS are in aloose state during the testing because there were no tamping been applied onthe samples. Overall the circular patch (CP) specimen was the most favourablethan the other configurations. Both mechanisms contributed to the reducedoverall subsistence, accompanied by an increase in the shear resistance. Theinclusion of rubber elements apparently prevented the dilation of the granularmaterial when approaching the shear failure and the reducing the settlement."

"Nanostructured zincoxide (ZnO) was synthesized via a sonochemical method. The effect of the duration of ultrasonic irradiation in a continuous mode on the generated particles was investigated. Additionally, the effect of flowing either air or nitrogen during the sonication process was investigated. Zinc nitrate andammonia water-based solutions were selected as chemicals without the additionof other surfactants. The generated particles indicated that a wurtzitestructure of ZnO in a hexagonal phase was formed with a crystalline size that increasedas the ultrasound irradiation time increased. The morphology of the generatedZnO particles could be changed from flowerlike to needlelike structures viacontinuous ultrasound irradiation over one to two hours, resulting in increasesin the particle lengths and decreases in the particle diameters from 200 to 80nm. Photoluminescence intensity was also increased with increases in the ultrasonicirradiation times. Photoluminescence spectra were also influenced by theatmospheric environment. Two bands centered at 390 and 500 nm were generatedunder a nitrogen environment. On the other hand, a single wide band with a peakat around 430 nm was found for particles generated under an air environment. Itcan be applied for light emitting diodes (LED) or laser fabrication with acontrolled emitting band."

"Fluorine-doped tin oxide (FTO) is one of the conductive glasses that have strategic functions in various important applications, including dye-sensitized solar cell (DSSC). In the current work, the effects of deposition time (5, 10, 20, 30, and 40 minutes) upon the fabrication process of FTO thin film using spray pyrolysis technique with modified ultrasonic nebulizer has been studied in regard to its microstructural, optical, crystallinity, and resistivity characteristics. The variation was also performed by comparing the pure tin chloride precursor and the solution that was doped with fluor (F) at 2 wt% in order to see the doping effect on the properties of thin film. The thin films were characterized using x-ray diffraction (XRD), scanning electron microscope (SEM), ultraviolet-visible (UV-Vis) spectroscopy, and digital multimeter. On the basis of current investigation, it has been found that the best FTO was obtained through the pyrolysis technique of 20-minute deposition time, providing optical transmittance of 74%, a band gap energy (Eg) of 3.85 eV and sheet resistance (Rs) of 7.99 Ω/sq. The fabricated FTO in the present work is promising for further development as conducting glass for dye-sensitized solar cell (DSSC)."

"ABSTRACTResearchers have started focusing their research on alternative fuels. During the last two decades, Dimethyl Ether (DME) has emerged as a new potential fuel to subtitute for oil and its derivatives. Raw materials for DME from sources such as coal, biomass, natural gas and also crude oil are spread all over the world so the interest is growing for using it as an energy source. While the technology for processing raw materials into DME is well established, the technology for DME applications for a wide range of usages is still being developed. The range of DME usage includes for automotive purposes, in industrial sectors, for household applications, and there is even fundamental research to discover more knowledge about DME safety and another technical considerations. Many research activities are now intensively been used to develop the technology for DME application. Some opportunities for discovering more application are also discussed in this paper."

"Dewasa ini, telah hadir beragam energi terbarukan untuk mensubtitusi energi fosil sebagai bahan bakar kendaraan bermotor, salah satunya ialah dimetil eter. Dimetil eter merupakan bahan bakar langsung maupun campuran untuk bahan bakar khususnya pada mesin diesel. Seperti halnya gasoline, dimetil eter dapat menyebabkan degradasi swelling material seal pada bagian mesin diesel. Material seal yang umum digunakan ialah karet nitril NBR yang tahan terhadap kontak dengan hidrokarbon dan juga unggul sifat fisiknya. Dalam rangka memanfaatkan penggunaan karet alam didalam industri otomotif, peneliti melakukan campuran karet alam NR dan karet nitril 33 acrylonitrile NBR33 untuk menghasilkan karet yang memenuhi standar aplikasi material seal.. Penelitian ini akan meneliti mekanisme yang terjadi pada degradasi campuran karet alam dan karet nitril NR/NBR33 oleh dimetil eter. Variasi campuran vulkanisat karet NR/NBR33 yang digunakan secara berurutan yaitu 1:3, 1:2, 1:1, 2:1, 3:1 Metode untuk mengetahui mekanisme tersebut meliputi karakterisasi mekanis mencangkup: perubahan massa, kekuatan tensile, elongasi maksimum, kekerasan dan karakterisasi morfologis dengan pengamatan morfologis menggunakan Scanning Electron Microscopi SEM . Data penelitian menunjukkan bahwa setiap variasi sampel campuran vulkanisat mengalami peristiwa degradasi swelling dan dissolution. Peningkatan rasio karet nitril NBR33 pada vulkanisasi campuran karet dapat mengurangi penurunan tensile strength dan elongation hingga melampaui sifat fisik sebelum perendaman oleh dimetil eter. Dengan demikian, variasi elastomer terbaik diperoleh setelah membandingkan dengan standar kelayakan material seal yakni campuran vulkanisat karet NR/NBR33 dengan rasio 40 : 60 NR : NBR.

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Today, there is present a variety of renewable energy to substitute fossil energy as a fuel for motor vehicles, one of which is dimethyl ether. Dimetl ether is a direct fuel or a mixture of fuel, especially diesel engines. In addition, dimethyl ether also has met the standard criteria for renewable energy. Semelsberger et.al., 2005 . As with gasoline, dimethyl ether can cause swelling degradation of the material seal on the diesel engine. Seal material that is commonly used is a nitrile rubber NBR that is resistant to contact with hydrocarbons and also superior physical properties. In order to make use of natural rubber in the automotive industry, researchers conducted a blending of natural rubber NR and nitrile rubber NBR to produce rubber meets the standard seal material application .. This study will examine the mechanisms that occur in the relegation blending natural rubber and nitrile rubber NR NBR by dimethyl ether. Nitrile rubber types used medium quality nitrile rubber with acrylonitrile content of 33 NBR33 . Methods to determine the mechanism includes mechanical characterization covers change in mass, tensile strength and maximum elongation, hardness and morphological characterization with morphological observations using Scanning Electron Microscopic. Observations of this study is limited which is to see the effect of variation vulcanized blending ratio NR NBR33 against degradation swelling. Variations blending vulcanized NR NBR33 are used in a sequence that is 1 3, 1 2, 1 1, 2 1, 3 1. The results of this research is to determine the most optimal value ratio elastomer that is resistant to swelling degradation depend on physical and structural changes. The increase nitrile rubber NBR33 ratio of blending rubber vulcanized can reduce the decrease of tensile strength and elongation until exceed physical properties before immersion with dimethyl ether. Thus, the best elastomer variation was obtained after comparing with the standard feasibility material of seal is rubber vulcanized blending NR NBR33 with ratio 40 60 NR NBR."

"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."

"Bahan aditif BNA-R dan Zeolit dapat mempengaruhi kekesatan permukaan pada campuran aspal hangat, terutama pada bagian permukaan aspal sebelum terlintasi dan sesudah terlintasi sebanyak 7560 lintasan dengan menggunakan Wheel Tracking Machine. Pengujian skid pada penelitian ini menggunakan alat British Pendulum Tester yang telah dimodifikasi agar dapat dilakukan pengujian dengan temperatur yang diinginkan. Hasil penelitian menunjukkan bahwa BNA-R dapat meningkatkan nilai skid pada awalnya, namun BNA-R tidak dapat mempertahankan kenaikan nilai skid tersebut setelah campuran aspal dilintasi sebanyak 7560 lintasan. Untuk bahan tambah zeolit terbukti bahwa aditif tersebut dapat meningkatkan nilai skid dan menaikkan ketahanan aspal terhadap temperatur.

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BNA R and zeolite additives can affects the skid resistance of warm mix asphalt, especially on the surface of the asphalt before it passes through and after 7560 as many passes through the track by using the Wheel Tracking Machine. This study used a British Pendulum Tester, which has been modified in order to be tested with the desired temperature.

The results showed that the BNA R can increase the value of skid at first but BNA R can not sustain the increase in the value of the skid after the asphalt is crossed by as much as 7560 tracks. For added zeolite material is proven that such additives can increase the value and increase skid resistance versus asphalt temperature."