Papers by Keyword: Reduction

Abstract: Climate change in Indonesia is receiving a lot of concern as the nation is the top ten world largest emitter of the greenhouse gases. To relieve the concern, Indonesia had proposed to cut the gas emissions by 26 percent by 2020 from business-as-usual (BAU) levels and proposed a 41 percent emission reduction below BAU target conditional to international support for Nationally Appropriate Mitigation Actions (NAMAs). This study deals with the strategy in reducing the acceleration of the greenhouse gas emission from the power sector in Southeast Sulawesi, a developing province in Indonesia with its high electricity demand in recent years. It calculates of the annual greenhouse emission from the electricity generation mix in this province, using the projected annual electricity generation and projected power plants installed under the power supply business plan (RPUTL) of the state electricity company (PLN Indonesia) and the lifecycle carbon dioxide emission equivalent. Some scenarios are proposed, by varying the power generation mix in the case of inclusion and exclusion the projected clean renewable powers in the year of 2020 and 2022. The result shows that in 2020, by the inclusion of the projected clean renewable powers in the power generation mix (around 5 percent), it can reduce the annual greenhouse gas emission almost 6 percent. In 2022, by maintaining the amount of the power generation from fossil sources as those in 2020 and maximizing the use of the clean powers in the electricity generation mix (around 20 percent), under the power provision plan, it can reduce the emission by 26 percent.

Abstract: The solid state reduction of ilmenite was studied using thermogravimetric analysis by a combination of XRD, SEM& EDS methods. Results showed that MgTiO₃ was the main impurity and influenced the reduction process of ilmenite. When the temperature was below 1000°C, reduction was controlled by the chemical reaction and the activation energy was 163 kJ/mol. Pretreatment of milling accelerated the solid reduction rate.

Abstract: The present manuscript is designed to investigate the possibility of manufacturing iron-metal alloys (Fe-M) via thermal techniques. These techniques are mainly depends on simultaneous reduction-sintering reactions of metal oxides. The reduction of metal oxides is an important property in metallurgical processes. It can be applied to M-Fe-O systems and also is used to develop inter-metallic alloys with specific properties. The produced metallic materials have wide range of applications and are characterized by unique physical and mechanical properties. The composition of the produced alloys is often a key element in optimizing their properties. Iron oxide doped another metal oxide such as nickel oxide is used as starting materials to produce metallic materials containing iron contaminated with nickel metal using thermal techniques. The sintering-reduction reactions of the composite oxide materials are investigated under different operation conditions. The experimental results show that the reduction-sintering thermal techniques are economic and promising routes for the production of different Fe-M alloys. The different factors affecting the rate of reduction such as temperature and ratio of doping materials are investigated. The results obtained are used to demonstrate the kinetics and mechanisms of reduction of metal oxides.

Abstract: Here results of computer analysis of sinking pass of aluminum alloys in the one and two dies are widely used in aircraft construction and engineering. As a method of computer simulation of finite element method used in the program DEFORM - 2D.

Abstract: The distinctive paper is devoted to application of wavelet-based discrete-continual finite element method (WDCFEM), to analysis of plates with piecewise constant physical and geometrical parameters in so-called “basic” direction. Initial continual and discrete-continual formulations of the problem are presented. Due to special algorithms of averaging using wavelet basis within multigrid approach, reduction of the problem is provided. Resultant multipoint boundary problem for system of ordinary differential equations is given.

Abstract: The results of experimental investigations of combustion of the powder mixture of titanium, carbon, and ferrous oxide (III) are shown in this paper. Iron reduction by carbon is an endothermic reaction and proceeds in combustion wave of SHS due to the heat of high-exothermic reaction of TiC formation. It was found that it is impossible to initiate the combustion process with (Fe₂O₃+C) content of 50 wt. % or more of the initial charge composition. With not very high content of (Fe₂O₃+C), only Fe and TiC are found in the reaction products. When approaching its content to 50 wt. %, also С and FeO impurity phases are detected. The SHS product is a cake of separate granules of Fe-TiC with the granule size of 100-500 μm.

Abstract: The reduction behaviour of 3% cerium doped (Ce-Fe₂O₃) and undoped iron oxide (Fe₂O₃) by hydrogen in nitrogen (10%,v/v) and carbon monoxide in nitrogen (10%,v/v) atmospheres have been investigate by temperature programmed reduction (TPR). The phases formed of partially and completely reduced samples were characterized by X-ray diffraction spectroscopy (XRD). TPR results indicate that the reduction of Ce doped and undoped iron oxide in both reductants proceed in three steps reduction (Fe₂O₃ → Fe₃O₄ → FeO → Fe) with Fe₃O₄ and FeO were the intermediate. TPR results also suggested that by adding Ce metal into iron oxide the reduction to metallic Fe by using both reductant gaseous give better reducibility compare to the undoped Fe₂O₃. The reduction process of Ce and undoped Fe₂O₃ become faster when CO was used as a reductant instead of H₂. Furthermore, in CO atmosphere, Ce-Fe₂O₃ give complete reduction to metallic iron at 700 0C which about 200 0C temperature lower than other samples. Meanwhile, XRD analysis indicated that Ce doped iron oxide composed better crystallite phases of Fe₂O₃ with higher intensity and a small amount of FeCe₂O₄.

Abstract: Noise – as a risk factor in the environment – in case it exceeds the intensity limits it becomes a biological aggression factor, a medical and social contaminant with implications of prime importance in terms of health, work capacity and comfort.This research is an objective analysis of noise level and frequency spectrum emitted by gas compressor Compressco CJ 360 in order to identify and develop solutions for noise protection required for the establishment of the environmental conditions in accordance with legal regulations in the area desired by the beneficiary. The research proposes a technical solution for closing the compressor with sound insulation prior to placing it in the desired place, in suitable environmental conditions.

Abstract: Oxide particles of Fe-77Ni alloy scraps were reduced by hydrogen gas on the effect of temperature and time. The chemical composition of metallic powder was examined by X-ray diffraction (XRD) and FeNi₃ alloy was finally obtained with a mean particle size of 10μm.

Abstract: Graphene oxide (GO) reduction is a promising way for graphene large scale synthesis. Pre-exfoliated graphite was oxidized and reduced. The material was compared to commercial graphene oxide and its reduced sample. The reduction process of graphene oxide is accomplished using sodium borohydride (NaBH₄) with variable-valence metal ion – cobalt – assistance. The reduced graphene oxide (RGO) was characterized by Raman spectroscopy. The particle size and suspension stability were determined. Electrical conductivity measurements of GO and RGO samples have been done in temperature range from-150°C to 85°C. Pre-exfoliation effect was determined.