Daratha N.,University of Bengkulu |
Das B.,Indian Institute of Technology Roorkee
International Journal of Electrical Power and Energy Systems | Year: 2015
This paper proposes a robust optimization technique to solve the voltage regulation problem in unbalanced radial distribution system in the presence of uncertainties in loads and distributed generation. The formulated problem is a mixed-integer nonlinear programming (MINLP) one and, to solve this MINLP problem efficiently, a two stage approach has been developed. To verify the robustness of the solution obtained by the proposed method, extensive Monte Carlo simulations studies have also been carried out. The efficacy of the proposed method has been tested in modified IEEE 123 bus unbalanced radial distribution system. ©2015 Elsevier Ltd. All rights reserved.
Hermawan B.,University of Bengkulu
International Journal on Advanced Science, Engineering and Information Technology | Year: 2016
The reclamation areas of the opencast coal mining in South Sumatera are predominantly compact and nutrient-poor, marginal sites but have a high potential for cultivation of fast-growing trees and agricultural crops. This paper aims to promote several models of agroforestry in the post-mined land in South Sumatera as a new strategy in reclaiming degraded soil properties for both enviroment and economic purposes. About 5,000 ha of coal mining areas were observed to characterize the landscape and soil properties in the area, then overlaid with the landuse maps of post-mining plans issued by the company. Results showed that about 1,730 ha of the reclamation areas was suitable for agroforestry while the rest was for utilities, camping ground, water pond and grassland. Three models were proposed for the agroforestry areas, including (i) agrisilviculture model (1,190 ha), (ii) silvihorticulture model (203 ha), and (iii) local-species collection model for agrihortisilviculture (337 ha). Prior to the agroforestry establishment, all reclamation sites were subjected to the revegetation with fast-growing trees and other rejuvenation treatments in order to restore favour soil and microclimate conditions. The proposed components for each model were as follows: for agrisilviculture model were cultivation on the alley cropping system of trees and food crops, for silvihorticulture model were the plantation of fruit trees in the bench of water pond, and for local-species collection model for agrihortisilviculture were the cultivation of local forest and food crop species.
Pranoto Y.,Gadjah Mada University |
Anggrahini S.,Gadjah Mada University |
Efendi Z.,University of Bengkulu
Food Bioscience | Year: 2013
Sorghum flour was either naturally fermented or inoculated by Lactobacillus plantarum at 37 °C for 36 h. Changes in bacteria, pH, acidity, protein, in-uitro protein digestibility (IVPD), starch content and in-uitro starch digestibility (IVSD) were monitored every 4h. Pasting properties were carried out only in the native sorghum flour, and two types of fermented flour with highest improved IVPD and IVSD. Results showed that both fermentation types increased total bacteria by 5 log, lactic acid bacteria (LAB) by 5 log, and proteolytic bacteria by 2-3 log cycles. The pH decreased from 5 to 3 with the increased of titratable acidity. Natural and L. plantarum fermentations for 36 h improved IVPD by 46.89% and 92.08%, respectively, and increased IVSD by 71.48% and 65.63%, respectively. The highest IVSD enhancement (78.69%) was shown by L. plantarum for 28 h. Fermentation decreased gelatinization temperature (GT), increased peak viscosity (PV) and hot paste viscosity (HPV). The greatest improved viscosities were shown by L. plantarum. © 2012 Elsevier Ltd.
Chinnusamy T.,University of Regensburg |
Yudha S S.,University of Regensburg |
Yudha S S.,University of Bengkulu |
Hager M.,University of Regensburg |
And 2 more authors.
ChemSusChem | Year: 2012
Over the years, organic synthesis has witnessed several improvements through the development of new chemical transformations or more efficient reagents for known processes. Likewise, technological advances, aiming at speeding up reactions and facilitating their work-up, have established themselves in academic as well as in industrial laboratories. In this Minireview, we highlight very recent developments in flow chemistry, focusing on organometallic reagents and catalysts. First, we describe reactions with homogeneous catalysts immobilized on different support materials using the concept of packed bed reactors. In the last chapter, we will discuss applications that utilize organometallic reagents. Down and up: Downscaling reaction vessels and moving to a continuous flow approach have not only advanced many reactions with respect to efficiency and safety, but also offer a reliable solution for upscaling chemical transformations. Examples in this Minireview demonstrate the use of sensitive metal-based reagents, substrates, and catalysts at extreme temperatures. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.
Yudha S S.,University of Bengkulu |
Dhital R.N.,Graduate University for Advanced Studies |
Sakurai H.,Graduate University for Advanced Studies |
Sakurai H.,Japan Institute for Molecular Science |
Sakurai H.,Japan Science and Technology Agency
Tetrahedron Letters | Year: 2011
Glycerol was oxidized catalytically under aerobic conditions in the presence of monometallic nanoclusters of gold on poly(1-vinylpyrrolidin-2-one) (PVP) to give hydroxymalonic acid (tartronic acid) as the major product, together with 2,3-dihydroxypropanoic acid (glyceric acid) and hydroxyacetic acid (glycolic acid) as minor products. In contrast, oxalic acid was selectively obtained when bimetallic Au-Pd:PVP nanoclusters were used as the catalyst. © 2011 Elsevier Ltd. All rights reserved.