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"The electronic and optical properties of a-Al2O3 after induced by 3-keV Ar+ sputtering have been studied quantitatively by use of reflection electron energy loss spectroscopy (REELS) spectra. The band gap values of a-Al2O3 was determined from the onset values of the energy loss spectrum to the background level of REELS spectra as a function of time Ar+ bombardment. The bandgap changes from 8.4 eV before sputtering to 6.2 eV after 4 minutes of sputtering.The optical properties of α-Al2O3 thin films have been determined by comparing the experimental cross section obtained from reflection electron energy loss spectroscopy with the theoretical inelastic scattering cross section, deduced from the simulated energy loss function (ELF) by using QUEELS-ε(k)-REELS software. The peak assignments are based on ELF and compared with reported data on the electronic structure of α-Al2O3 obtained using different techniques. The results demonstrate that the electronic and optical properties before and after surface reduction will provide further understanding in the fundamental properties of α-Al2O3 which will be useful in the design, modeling and analysis of devices applications performance."

"Biomassa merupakan energi alternatif yang dapat menjadi salah satu solusi untuk mengatasi krisis energi di Indonesia Torefaksi adalah proses pirolisa lambat tanpa oksigen yang memiliki rentang suhu 225 325oC Tujuan dari penelitian ini adalah mengetahui pengaruh torefaksi terhadap distribusi ukuran partikel biomassa kemudahan biomassa menyerap moisture content dan kekerasan dari pellet biomassa yang berasal dari bagas tebu Bagas tebu merupakan hasil samping dari pertanian yang pemanfaatannya masih terbatas Analisis yang dilakukan untuk mengetahui karakteristik tiap biomassa adalah daya serap moisture content dari biomassa distribusi ukuran partikel dan Brinell Hardness Semakin tinggi suhu torefaksi mengakibatkan semakin mudah biomassa di reduksi ukuran dengan persentase ukuran partikel kurang dari 125 m sebesar 43 55 pada suhu 325 C Torefaksi juga mengakibatkan kemampuan biomassa menyerap moisture content semakin kecil Pada suhu 325 C kandungan moisture content sebesar 2 92 Seiring kenaikan suhu torefaksi biomassa semakin sulit menyerap moisture content Namun torefaksi menyebabkan sifat kekerasan Hardness pellet biomassa rendah Kenaikan suhu torefaksi menyebabkan sifat kekerasan Hardness pellet biomassa semakin rendah dengan nilai tertinggi pada pellet biomassa tanpa torefaksi sebesar 1 20 kg mm2.

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Biomass is an alternative energy that could become one of solution to overcome energy deficit in Indonesia Torrefaction is the process of slow pyrolysis without oxygen has a temperature range of 225 325oC The purpose of this research was to determine the influence on ease of torefaction of the particle size distribution of biomass biomass easily absorb moisture content and hardness of the pellet biomass derived from sugarcane bagasse Baggase a by product of agriculture which utilization is still limited Types of analysis to characterize the biomass as a result of torrefaction are absorptive capacity of the biomass moisture content particle size distribution and Brinell Hardness The higher temperatures result in more easily with the size reduction of biomass in the percentage of particle size less than 125 m was 43 55 at a temperature of 325 C Torrefaction also resulted in the ability to absorb moisture content of biomass is getting smaller At temperatures of 325 C the content of moisture content of 2 92 As the temperature rises biomass is increasingly difficult to absorb moisture content But the torrefaction of biomass pellets causes the hardness decreases Rising temperatures cause the hardness properties hardness the lower biomass pellets with high scores on biomass pellets of 1 20 kg mm2 "

"Green solvents volume I and II provides a throughout overview of the different types of solvents and discusses their extensive applications in fields such as extraction, organic synthesis, biocatalytic processes, production of fine chemicals, removal of hydrogen sulphide, biochemical transformations, composite material, energy storage devices and polymers. "

"Green solvents volume I and II provides a throughout overview of the different types of solvents and discusses their extensive applications in fields such as extraction, organic synthesis, biocatalytic processes, production of fine chemicals, removal of hydrogen sulphide, biochemical transformations, composite material, energy storage devices and polymers. "

"Biosorpsi Ion Timah Hitam (II) Menggunakan Sansevieria trifasciata Prain. Sansevieria trifasciata (yang dikenal sebagai tumbuhan ular atau lidah mertua) diduga dapat menjadi biosorben logam berat. Konsentrasi ion logam Pb (II) sebelum dan sesudah biosorpsi diukur dengan spektrofotometer serapan atom (SSA). Optimasi kemampuan S. trifasciata sebagai biosorben dilakukan menggunakan metode respon surface dengan variasi pada massa tumbuhan, pH larutan, waktu kontak, dan suhu. Kondisi biosorpsi optimal diperoleh pada pH 7, waktu 240 menit dan berat S. trifasciata 1.5 g dengan kapasitas biosorpsi Pb (II) sebesar 0.725 mg/g. Analisis isoterm adsorpsi menunjukkan biosorpsi mengikuti model isotherm Freundlich. Spektrum FTIR daun lidah mertua setelah diperlakukan larutan timah hitam (II) memperlihatkan intensitas puncak pada daerah 2130/cm. Mikrograf daun lidah mertua memperlihatkan struktur berpori dengan ukuran yang tidak seragam. Penyerapan Pb (II) pada serbuk daun S. trifasciata diketahui melalui analisis SEM EDX. Berdasarkan hasil penelitian, dapat disimpulkan bahwa S. trifasciata dapat digunakan sebagai biosorben untuk menghilangkan kontaminasi ion Pb.

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Sansevieria trifasciata (also called snake plant or mother in law?s tongue) is predicted to act as a heavy metal biosorbent. S. trifasciata was optimized as a biosorbent by using the response surface method with varying weights of S. trifasciata, pH of Pb (II) solutions, contact times, and temperatures. The ion concentration before and after biosorption was measured with an atomic absorption spectrophotometer (AAS). The optimum biosorption conditions were pH 7, 240 min contact time, and 1.5 g biosorbent with biosorption capacity of Pb (II) ions 0.725 mg/g. The biosorption isotherm analysis showed that the biosorption is consistent with the Freundlich isotherm model. The peak intensity of the FTIR spectrum of S. trifasciata after treatment with Pb (II) was around 2130/cm. The S. trifasciata micrograph showed a porous structure with non-uniform pore sizes. The biosorption of Pb (II) ions on powdered S. trifasciata leaves was found with the SEM EDX analysis. It is concluded from this research that S. trifasciata can be used as a biosorbent to remove Pb ion contamination."

"Sifat Panas, Kristalinitas, dan Permeabilitas Oksigen Film Poly(lactic acid) Terplastisasi diperkuat Na- montmorillonite. Pembuatan film komposit poly(lactic acid) terplastisasi PEG400 dengan bahan penguat Na- monrmorillonite (NA-MMT) dilakukan dengan metode direct casting. Film komposit PLA terplastisasi dilakukan uji struktur komposit, sifat panas, derajat kristalinitas dan permeabilitas terhadap oksigen. Pengujian sifat panas dan penghitungan derajat kristal diperoleh dari pengukuran differential scanning calorimetry (DSC), analisis struktur komposit menggunakan xray diffraction (XRD) dan pengukuran permeabilitas oksigen menggunakan dynamic accumulation method. Film komposit PLA terplastisasi dengan bahan penguat Na-MMT menunjukkan terjadinya interkalasi polimer Na-MMT dengan pergeseran sudut difraksi sebesar 0.2o. Stuktur kristal yang terbentuk memiliki bentuk alpha dan derajat kristal film komposit meningkat dari 34% menjadi 52%. Parameter sifat panas film PLA terplastisasi dengan bahan penguat Na-MMT mengalami perbaikan suhu transisi gelas dari 53 °C menjadi 57 °C meskipun suhu leleh tidak mengalami perubahan tetap bekisar pada nilai 167 °C. Peran Na-MMT membentuk jalur liku sebesar 20% sehingga terjadi peningkatan daya halang oksigen film komposit PLA terplastisasi yang ditunjukkan dengan penurunan nilai permeabilitas sebesar 80%. Penambahan Na-MMT sebesar 3% dalam pembuatan film komposit PLA terplastisasi cukup untuk mendapatkan keseimbangan perbaikan sifat panas, kristalisasi, dan daya halang oksigen.

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Introducing unmodified organically clay/Na-montmorillonite (Na-MMT) was applied into plasticized poly(lactic acid) PLA to produce film composites by direct casting. Film composite structure, the crystallinity degree and form, and thermal properties were carried out using X-ray diffraction and differential scanning calorimetry. The effect of Na- MMT to the tortuous path and the crystallinity degree in the plasticized film composites were calculated in oxygen barrier properties. Chromatogram film composites resulted in an intercalated structure that showed peak diffraction angle shift at about 0.2o. Then, a peak diffraction pattern was indicated in α-form crystal structure. Plasticized PLA has a crystallinity degree at 34%, and the addition of Na-MMT increased to 52%. Glass transition temperature improved from 53 °C to 57 °C, and melting temperature remained stable at 167 °C. Filling Na-MMT into plasticized PLA caused to enhance a tortuous path about 28% and improved the oxygen permeability to 80%. As a result, the addition of Na- MMT of 3% into plasticized PLA during film composite preparation using the mixing method resulted in balancing properties related to the crystallinity degree, thermal properties, and oxygen barrier properties."