Praperlakuan secara Hidrotermal Limbah Lignoselulosa untuk Produksi Bioetanol Generasi Kedua (Pretreatment of Lignocellulose Wastes Using Hydrothermal Method for Producing Second Generation Bioethanol)

The second generation of bioethanol derived from various cellulosic biomass materials is one of the latest renewable energy as the alternative of fossil fuel. The cellulosic waste based wood and non-wood materials are the most abundant natural resource on the earth, renewable, and inexpensive. Currently, second generation bioethanol development is still not optimally done due to various obstacles, especially the pretreatment process to eliminate lignin, influencing the conversion process of cellulose into reducing sugar. Hydrothermal method is one of lignocellulose pretreatments, which is widely developed because this method is relatively cheap and environmentally friendly with the utilization of water-based solvent. Hydrothermal methods performed at high temperature and pressure in a relatively short time are able to deconstruct the lignocellulose structure that enables cellulase enzymes to access cellulose for hydrolysis. This study discussed about the development of hydrothermal method for lignocellulose pretreatment process to increase production of second-generation bioethanol. Some aspects studied in this research were structural change, chemical composition, lignocellulosic crystallinity before and after hydrothermal processes, and hydrothermal effect on the production of reducing sugars. Hydrothermal method could be used and developed as an efficient and cheap method as the first treatment of lignocellulose waste in attempt to increase the production of bioethanol.

Cleanness and Mechanical Properties of Steel after Remelting under Different Slags by ESR

Quality of machine production is very close-knit with quality of metallurgical semi-products and with improvement their working properties. It can be achieved first of all by decrease of sulphur and non-metallic inclusions content in metal. Improvement of working properties provide remelted processes above an electro slag remelting (ESR). The slags play very important role by ESR process. By experiments steel with next chemical composition was used: C (0,9 – 1,1%), Mn (0,30 – 0,50%), Si (0,15 – 0,35%), Cr (1,30 – 1,65%), Ni (max.0,30%), Cu (max.0,25%), P (max.0,027%), S (max.0,030%). The steel was remelted under 8 types of slags on the base of CaO, Al2O3, CaF2 and SiO2 in different ratios. The contribution deals with influence of chemical composition of slag on mechanical properties and cleannes of metal after electro slag remelting. Variation of slag chemical composition enables to change chemical composition of remelted steel, to reduce the non-metallic inclusions and sulphur content and to improve the mechanical properties of steel.

Failure Analysis of Electronic Material Using Cryogenic FIB-SEM

Two-beam systems (focused ion beam (FIB) integrated with a scanning electron microscope (SEM)) have enabled site-specific analysis at the nano-scale through in situ “mill and view” capability at high resolution. In addition, a FIB-SEM can be used to cut away a lamella from a bulk sample and thin it for transmission electron microscopy (TEM) imaging. We studied the temperature dependence of FIB milling on compound semiconductors and thin films such as copper that are used in integrated circuits. These materials (GaAs, GaN, InN, etc) react chemically and physically with the gallium in the FIB and change chemical composition and may also change morphology. Copper metallization of IC’s has been difficult to mill without undesirable side effects. FIB milling for analysis of these materials becomes difficult if not impossible. Since temperature can be a big factor in chemical and physical reactions we investigated this and report here the effect of cooling the sample to cryogenic temperatures while milling. In addition, we report on the development of a process to prepare TEM lamellae with FIB entirely in a cryogenic environment.