ENHANCED HYDROCARBON EXTRACTION FROM CALOTROPIS PROCERA - A PETROCROP

With fast disappearing petroleum reserves renewable resources like biomass are of great significance. Petrocrop, Calotropis procera is a wild shrub and does not compete with food and fodder crops for land. This paper presents an investigation on enhancement of hydrocarbon extraction from Calotropis procera. An extraction yield of 8% has been obtained with toluene, as solvent. Increase in extraction to 11.5% has been achieved by modification of design of conventional “Soxhlet extractor”. Further enhancement in extraction has been achieved by pre-treatment of the biomass with alkali or acid. Pre-treatment results in extractive or hydrolytic breakdown of plant structure and hence exposes hyrocarbons to solvent attack. Alkali pretreatment of ground biomass resulted in much higher extraction. So it was studied in further detail with more alkalies of varying strength. An enhancement from 8% to 18% has been achieved by pre-treatment with IN sodium hydroxide.     

New difference reflectance methods for study of small interfacial effects

Two sensitive differential optical techniques useful for study of small reflectance or absorptive differences between two interfaces are described. The first scheme employs a mechanically chopped light beam impinging on an arrangement of symmetrical dual cells to allow detection of differential reflectances DeltaR/R<10(-3). The second is a polarization-modulated beam-split laser version of the same method yielding approximately the same sensitivity. Representative measurements of voltage-induced reflectance changes at liquid-solid interfaces using these methods are given.     

Petroleum Source Rock Characteristics of the Lower Tertiary Formations in the Ereğli-Ulukışla Basin,Southern Central Anatolia,Turkey

Abstract

Potential source rocks in the Ere?li-Uluk??la basin include Campanian-Maastrichtian limestones and marls, Upper Paleocene-Lower Eocene deep-marine shales, and Middle-Upper Eocene continental slope deposits, including shales and sandstones. Organic geochemical analyses and palynofacies observations show that the organic components in Upper Paleocene-Upper Eocene sediments are mainly coaly and woody, with minor herbaceous and algal-amorphous-like organic matter, indicating that they are terrigenous (mainly Type III and Type IV kerogen). The organic carbon content of these rocks ranges from 0.04 to 0.73%, and they have marginal source rock quality for oil generation. A plot of HI versus T-max values implies that the Upper Paleocene-Lower Eocene samples are in the early stage of oil generation, while the Middle-Upper Eocene samples are thermally immature. The pristane/phytane ratio for Tertiary samples corresponds to a transition from anoxic to oxic depositional conditions.     

Effects of different surface treatments on shear bond strength between ceramic systems and metal brackets

The aim of this study was to evaluate the shear bond strength of orthodontic brackets bonded to different kinds of ceramic surfaces after different surface conditioning methods. A total of 120 ceramic disks were divided into two main groups in terms of feldspathic or lithium disilicate. Each ceramic group was further subdivided into six subgroups depending on surface treatment (n = 10). The ceramic surfaces were conditioned by one of the following methods: Group C: control group; Group P: %37.5 orthophosphoric acid; Group HF: %9.6 hydrofluoric acid; Group L: Nd-YAG laser irradiation; Group SB: sandblasting with 50 µm Al₂O₃ particles; and Group DB: grinding with a diamond bur. Surface roughness value was evaluated with a digital profilometer. Surface topographies of one specimen from each group were observed by atomic force microscopy (AFM) after surface treatments. All samples were primed with silane before the bracket bonding, including the control group. Metal brackets were bonded to the specimens with a light curing composite resin. The samples were stored in distilled water for 24?h and thermocycled 2500× at 5 and 55 ºC for 30?s. Shear bond strengths between the ceramic surface and the bracket were measured with a universal testing machine at a crosshead speed of 0.5 mm/min. Failure modes were classified as adhesive, cohesive, or mixed. Data were analyzed using ANOVA and Tukey's tests (α = .05). Group SB had significantly rougher surface compared with the other groups in each ceramic system (p < .05), and Group SB demonstrated significantly higher shear bond strengths than other groups as well. Within the limitations of this study, surface conditioning methods, except for sandblasting and grinding, were associated with lower shear bond strengths; however, thermocycling may have had negative effects on bond strengths of specimens. Furthermore, in each ceramic system, there was a significant difference between surface-conditioning methods and surface roughness with regard to shear bond strength.     

Load reallocation based algorithm for state estimation in distribution networks with distributed generators

In this paper is proposed a novel branch flow and weighted least square (WLS) based algorithm for state estimation in three phase distribution networks with distributed generation (DG) units. The basic formulation is simplified by the use of radial property of distribution network and later will be extended to meshed networks. Unmonitored (or partially monitored) loads are initially estimated from normalized daily load profiles (NDLPs) with lower weights (treated as the pseudo measurements). Also, the different types of monitored, partially monitored, or unmonitored DG units are included in state estimation. Their initial power outputs are calculated on the basis of external inputs, such as wind, sun and water inflow forecasts etc. (depending on DG unit type) or by normalized daily generation profiles (NDGPs) obtained from historical generation data. The pseudo measurements obtained by Initial Load/Generation Allocation are re-adjusted additionally by Optimal Load/Generation Reallocation procedure to fit real-time measurements inside WLS-based state estimation. The results and practical aspects of the proposed methodology are demonstrated on two real-life distribution networks.