Pembuatan Bioetanol Dari Pati Umbi Kimpul (Xanthasoma Sagittifolium )

Bioetanol merupakan energi terbaharukan yang dapat mengatasi krisis energi yang disebabkan berkurangnya energi yang berbasis fosil. Produksi bietanol umumnya menggunakan bahan yang mengandung karbohidrat sebagai bahan baku umumnya yang digunakan sumber makanan pokok pengganti beras misalnya ketela. Salah satu alternative bahan baku yang tidak mempengaruhi sumber makanan pokok adalah umbi kimpul ( Xanthasoma sagittifolium .). Umbi kimpul kandungan karbohidratnya sekitar 34,2 gr per 100 gr berat bahan Proses yang umum digunakan adalah fermentasi. Diharapkan perolehan alkohol lebih banyak dengan memvariasikan waktu fermentasi ( 1, 3, 5, 7 dan 9 ) hari , jumlah enzim α-amilase ( 1; 1,5; 2; 2,5; dan 3 ) dan glukoamilase yang ditambahkan ( 1; 1,5; 2; 2,5; 3 ). Proses ini terdiri tiga tahap yaitu likuifikasi, sakarifikasi dan fermentasi. B ioetanol yang diperoleh kadarnya 9 % dalam waktu fermentasi 7 hari. Sedangkan dengan enzim α-amilase dan glukoamilase 2 ml diperoleh alkohol masing – masing kadarnya 9,5 % . Hasil studi menunjukan bahwa umbi kimpul tersebut dapat digunakan sebagai sumber bahan untuk memproduksi bioetanol

Ketahanan Oksidasi Baja Super Austenitik 15%cr-25%ni Pada Suhu 850 °C

OXIDATION RESISTANCE OF SUPER AUSTENITE 15%Cr-25%Ni STEEL AT TEMPERATURE 850 oC. High temperature corrosion resistance so called oxidation resistance is an important prerequisite of a metal material that may be applied in a high-temperature operating environment.An oxidation test of super austenite steel 15% Cr-25% Ni at 850 oC for more than 5 hours has been performed. One as-cast specimen as an initial reference is not treated any heat and two (2) specimen groups (each of 4 pieces) were prepared in the experiments. One group of as-cast specimens after being heated at 850 oC for more than 5 hours and cooled slowly then weighed.Another group of quench specimens performed a rapid decrease of temperature (850 oC formore than 5 hours) into water, then weighed. The experiment was conducted for more than 15 hours in each group. The results show that there is a very small slight increase in weight on as-cast and quench specimens. However, electron microscopemorphology (SEM) images on both specimens showed no significant changes. Similarly, the results of phase analysis using X-ray diffraction techniques also do not show the phase growth of oxidation products. In accordance with the observation of surface microstructures of materials by using optical microscope (OM), also did not show damage and changes in grain size by oxidation process. The likelihood of this phenomenon is that in addition to the formation ofNi element of spinels, it is also strengthened by the ability of Cr-elements to form a passive layer (Cr2O3) on a very large material surface by binding O-elements, so that the material can cope with very small oxidation products. It is concluded that the super austenitic steels has good oxidation resistance at 850oC

Some Metal Oxide-Natural Rubber Composites for Gamma- and Low-Energy X-Ray Radiation Shielding

This work studied protective material consisting of several metal oxide composites (Pb3O4, WO3, SnO2, and Bi2O3)-natural rubber (NR) for X-ray and gamma-ray shielding. The composites were prepared through open milling and vulcanization processes and further characterized by scanning electron microscope (SEM), X-ray diffraction (XRD), rheometry analysis, and density gauge. The attenuation coefficient of the sample was investigated using X-ray generators with voltages ranging from 50 to 140 kV and gamma-ray energies ranging and 356 to 1250 keV, respectively. The experimental results show that the linear attenuation coefficient of NR filled with metal oxides was significantly improved compared to pure NR. For gamma-ray 661 keV, the HVL of NR decreased from 9.0 cm to between 4.4 - 6.2 cm after it was filled with metal oxides. The Bi2O3-NR is the best suitable material for gamma-ray attenuation, followed by Pb3O4-NR, WO3-NR, and SnO2-NR. Meanwhile, for x-rays, the HVL of NR decreased from 2.0 cm to between 0.17 -0.31 cm after it was filled with metal oxides. The proposed metal oxide-NR composites can be appropriate as a flexible protective material for manufacturing wearable radiation shielding products such as gloves, aprons, rubber underwear, and other wearable materials

Sintesis Paduan Co-cr Menggunakan Metode Ultrasonik

Paduan Co-Cr merupakan material tahan suhu tinggi dan tahan korosi. Penelitian ini bertujuan mensistesis serbuk paduan Co-Cr dengan metode ultrasonik, kemudian dilanjutkan dengan proses sintering dalam kapsul kaca kuarsa. Iradiasi ultrasonik yang digunakan pada frekuensi 20 kHz dan amplitudo 40 % dengan komposisi Co : Cr sebesar 80 : 20.Waktu perlakuan sonikasi adalah selama 0 jam, 3 jam, 6 jam, 12 jam, 24 jam, dan 48 jamdalam larutan etanol. Setelah sonikasi selama 48 jam, fasa FCC dari Co mulai bertransformasi menjadi fasa HCP. Perlakuan ultrasonik terhadap campuran Co-Cr juga memberikan efek pengurangan ukuran partikel. Parameter kisi serbuk setelah ultrasonikasi 48 jam adalah: untuk HCP-Co a = b = 0,25074 nmdan c = 0,40699 nm, untuk FCC-Co a = b = c = 0,35411nm, dan untuk BCC-Cr a=b=c=0.28827 nm. Perlakuan ultrasonik selama 48 jam menhasilkan pembentukan paduan Co-Cr dengan persentasi berat sebesar 25,2124. Hasil sintering padatan Co-Cr menunjukkan parameter kisi HCP-Co memiliki nilai yaitu a = b = 0,25230 nm dan c=0,41223 nm, dan FCC-Co a = b = c = 0,35232 nm. Terbentuknya microalloying CoCr diindikasikan dari hasil EDS, teramati partikel yang mempunyai komposisi Co : Cr = 71,25 : 24,45. Paduan Co-Cr yang terbentuk setelah sintering pada 1300 oC adalah sebesar 15,33416 %berat

Synthesis of Nanofiber From Polyvinyl Alcohol (PVA)-Collagen Using Electrospinning Methods

Polyvinil alcohol (PVA) polymer can be used as matrix to be mixed with collagen in the subtance of primary wound dressing material to cover wound that prevents growth of bacteria and enhanced tissue formation. Collagen fiber is fragile, so important to combined with PVA to obtain better mechanical properties. The PVA-collagen fibers are prepared in aqueous solutions with PVA (10%) and collagen concentration (1% and 2%) using electrospinning method and the effect of voltage 15 kV, 19 kV, and 23 kV. Analysis of functional groups show that the presence of identical compounds produced and new functional groups are not formed. SEM data show that the effect of variation of voltage and collagen concentration on the resulting morphology of fiber. PVA-collagen 2% fibers produce continuous fibers, has a diameter 284-426 nm, thickness 0.0324-0.0483 mm and has a high percent of elongation so it can be used as a wound dressing material

Genome-wide Association Study of Birth Weight in Bali Cattle (Bos javanicus)

The genome-wide association study is popularly used to identify markers associated with high economic traits in cattle breeds worldwide. However, this method has never been applied to Bali cattle (Bos javanicus), which are indigenous to Indonesia. Therefore, this study aimed to determine whether the GWAS can also be employed to figure out genomic regions potentially affecting Bali cattle's birth weight trait. In this study, phenotypic and genotypic data of 48 Bali cattle were used to figure out genomic regions which are potentially affecting the birth weight trait of Bali cattle. Those samples were genotyped using an Illumina bead chip array with 53.218 single nucleotide polymorphisms (SNPs). The estimation of the variance proportion explained by each SNP was conducted by a restricted maximum likelihood (REML) approach. The result showed that the birth weight trait in Bali cattle was affected by multiple regions dispersed over the genome, especially chromosomes 20 and 21. This study demonstrated that GWAS can be used effectively and discovered two intriguing regions related to quantitative trait loci and genes, namely STXBP6 and TERT, which previously had been linked to cattle birth weight and growth. These findings are important for developing and refining genomic-based selection programs for Bali cattle in Indonesia