The Influence of Silane Gas Flow Rate on Optoelectronic Properties of µc-Si:H Prepared by HWC-VHF-PECVD Technique

Hydrogenated microcrystalline silicon (µc-Si:H) thin films have been deposited using 10% silane (SiH4) in H2 dilution by Hot Wire Cell Very High Frequency Plasma Enhanced Chemical Vapor Deposition (HWC-VHF-PECVD) technique. The resulted thin film characteristics were systematically studied as a function of the deposition parameter. The previous structural studies showed that the structural phase transition from amorphous to microcrystalline thin film was obtained using the filament temperature of 800 °C. In this study, the optoelectronic properties of µc-Si:H thin films were investigated as a function of the silane gas flow rate from 40 sccm to 80 sccm. The highest deposition rate of 3.6 A/sec and the lower optical bandgap of 1.4 eV were obtained using 80 sccm and 60 sccm of the silane gas flow rate, respectively. The film showed the photosensitivity of 3 x 107, which is quite high above the minimal value of 103 for solar cell application

Asphaltene Solvency and Stability of Water in Oil Emulsion: A Case Study of Two Nigerian Crudes

The effect of asphaltene solvency on the stability of water-in-oil emulsion was investigated using crude samples from two Nigerian oil wells, namely Okoro oil well (crude A) and Okpoho oil well (crude B), chosen because of their varying resin and asphaltene content. Solvency of the emulsion was modified by addition of heptane, toluene, and their blend (heptol) in various proportions. The effect of aqueous phase pH on the stability of the emulsion was also studied. The results showed that the Okoro well crude oil which has higher asphaltene content of 3.2 wt% and lower resin/asphaltene ratio of 1.15 formed a much more stable emulsion than that of Okpoho oil well which has 1.9 wt% asphaltene content and 3.16 resin/asphaltene ratio. It was also noticed that the emulsion became more destabilized at basic pH range. A model was developed which can be used to predict the stability of the water/oil emulsion in period of time beyond the study range. Keywords: water-in-oil emulsion, stability, asphaltene, resin, solvency, aromaticity

A Field Trial with the Insect Growth Regulator Oms-1390 Against Culex Pipiens Fatigans in Jakarta, Indonesia

Pemakaian "insect growth regulator" OMS-1390 dengan dosis 1 ppm untuk menahan perkembangan larvae Culex pipiens fatigans dalam 1 aplikasi penyemprotan memberikan efektifitas selama enam minggu.Percobaan ini diselenggarakan pada musim kemarau, di daerah yang padat penduduknya, seluas 1 km persegi di Jakarta, Indonesia

Pengaruh Posisi Sayatan Dan Penyisipan Entris Pada Batang Bawah Terhadap Keberhasilan Penyambungan Dan Kecepatan Pertumbuhan Benih Manggis

. Jawal, M. Anwarudin Syah, R. Poerwanto, T. Purnama, F. Usman, and I. Muas. 2007 . The effeect of Slice and Insertion Scion Position on Rootstock for Succ essful Grafting and the Growth of Mangosteen Seedling. The objective of this study was to find out the best position of slice and insertion of the scion on rootstock of mangosteen grafting. This study was conducted at nursery of Indonesian Tropical Fruit Research Institute Solok from July 2003 to March 2005 by using factorial randomized block design with 3 replications. The first factor was the slice position of scion (on the top the node, below the node, and at the node), while the second factor was the insertion position of scion on rootstock (on the top of the node, below the node, and at the node). The parameters observed were grafting successfulness, frequency of flush, leaf number, plant height, stem diameter, and number of lateral branch. The results indicated that slice position of scion at the node increased the successfulness of grafting and growth of mangosteen grafting. Insertion position of scion at the node increased the successfulness of grafting, while insertion position of scion on the top of the node stimulated the growth of mangosteen grafting

An independent framework for off-grid hybrid renewable energy design using Optimal Foraging Algorithm (OFA)

The rapidly increase in electrical energy demand from residential, commercial and industrial sectors is one of the major challenge in power system, especially in the current period of high oil prices, steadily reducing energy sources and increased concerns about environmental pollution. Renewable energy is considered as one of the solution to this increase in power demand. The conventional method of power system cannot meet the power demand for many reasons such as environmental effects, location of the consumer, price of fuel and others. This paper presents the design of an off-grid Hybrid Renewable Energy System (HRES) for electrification of a typical remote area. The designed hybrid system consists of three different configurations of PV/Battery, Wind/Battery and PV/Wind/Battery systems. The system components are modelled and the objective function is designed as a function of total annualized cost of the system subject to some constraints binding the decision variables. The total annual cost is formulated as a function of annual capital cost and annual maintenance cost of the system subject to some operational constraints. In order to determine the optimal number of the decision variables that would satisfy the load demand in the most cost effect manner, Optimal Foraging Optimization (OFA) algorithm was used. Finally, a simulation experiment shows that the total annual cost obtained by each algorithm for the PV/Battery system is $9,340.42 or N3,876,274.30,$9,446.77 or N3,920,409.55 and $10,076.34 or N4,181,681.1 for OFA, GA and PSO respectively. For the Wind/Battery configuration, the total annual cost obtained by OFA, GA and PSO are$17,508.20 or N7,265,903, $12,493.27 or N 5,184,707.05 and$16,535.93 or N6,862,410.95 respectively. Similarly, the PV/Wind/Battery configuration showed that the OFA, GA and PSO obtained an annualized cost of $15,926.07 or N6,609,319.05,$18,167.09 or N7,539,342.35 and $16,535.93 or N6,862,410,95 respectively. From the results obtained by OFA are compared with that of Genetic Algorithm (GA) and Particle Swarm Optimization (PSO) algorithm. Results showed that all the algorithm can efficiently size the hybrid system with OFA obtaining the most economical design. Therefore, for economically and efficiently electrification of a remote area in Abuja using an off-grid hybrid renewable energy system, GA optimization algorithm is recommended for wind/Battery system and OFA optimization algorithm is recommended for PV/Wind/Battery system

Price Transmission, Volatility and Discovery of Gram in Some Selected Markets in Rajathan State, India

Market integration in many agricultural commodities had been extensively studied for the insight it provides into the functioning of such markets, thus giving valuable information about the dynamics of market adjustment, and whether there exist market imperfection, which may justify government intervention. This study empirically investigated price transmission, volatility and discovery of gram across four wholesale gram markets, viz. Jaipur, Kishangarh, Chomu and Malpura in Rajasthan state of India using Johansen's multivariate cointegration approach, VECM, Granger causality tests, GARCH, EGARCH and ARIMA. Monthly wholesale gram price data spanning from January 2011 to December 2015 sourced from AGMARKNET were used. Multivariate cointegration showed that all the selected gram markets were cointegarted in the long-run, meaning long-run price association among these markets. The degree of market integration observed is consistent with the view that Rajasthan state gram markets are quite competitive; thus, provide little justification for extensive and costly government intervention designed to enhance market efficiency through improve competitiveness. Therefore, in order to sustain the present system of market integration, there is need to evolve mechanism that will generate market information and market intelligence which would serve as a platform for guiding farmers in marketing their produce

Chemical constituents and anti-inflammatory activity of leaf essential oil of Nigerian grown Chenopodium album L.

Hydrodistilled leaves of Chenopodium album yielded 0.64 % v/w of essential oil. GC and GC/MS analyses of the oil revealed that the bulk of the oil was constituted by aromatic compounds (60.1 %). The abundant constituents of the oil were: p- cymene (40.9 %), ascaridole (15.5 %), pinane-2-ol (9.9 %), α-pinene (7.0 %), β-pinene (6.2 %) and α-terpineol (6.2 %). The oil displayed strong anti-inflammatory activity against 12-O-tetradecanoylphorbol-13-acetate (TPA) – induced ear edema in mice