Fermentative production of rhamnosidase from Staphylococcus xylosus MAK 2 in a bioreactor for bio-energy generation

Increasing concern about the environment, food and feed shortages and hike in the price of petroleum have stimulated interest in new ways of producing biofuels. The interest is rapidly increasing towards converting agricultural wastes to commercially valuable products. Biofuels made from waste biomass can offer immediate and sustained greenhouse gas advantages. In this direction, we are focusing on Citrus processing waste, a byproduct of juice manufacture, which contains high amount of flavonoids and polysaccharides. There is a considerable industrial interest in the enzymatic transformation of flavonoids to hydrolysis products; that offers a pathway to bio-energy generation. Rhamnosidase of bacterial origin are very few and thus are potentially subject for research.

Staphylococcus xylosus, Gram positive cocci, a nonpathogenic member of CNS family, isolated from soil was used to produce α-L-rhamnosidase. This new strain, so far unknown for the production of α-L-Rhamnosidase, was identified and characterized as Staphyloccocus sp. through biochemical tests and 16S DNA sequence analysis. Effect of various medium and process parameters like pH, temperature, aeration and agitation rates and inducer concentration were studied. Further, the enzyme activity was enhanced by adding the inducer and divalent metal ion to the optimised fermentation medium. We have recovered important sugars “rhamnose” and “galacturonic acid” from the processed waste which would be utilized for ethanol production. This presentation will summarize current efforts to develop an enzymatic treatment which would facilitate the economical processing of citrus waste for bioenergy generation.

The effect of teaching conceptual and image metaphors to EFL learners

Foreign language learners encounter difficulties utilizing metaphorical expressions in everyday language, particularly because the use of metaphors in the discourse context is inescapable. In this study, efforts have been made to provide an effective way for the Iranian language learners to acquire and employ conceptual and image metaphors. The instruction took place on 60 junior students studying at the University of Petroleum Engineering at Ahvaz, a southern city in Iran, who were selected on the basis of their high marks on an English proficiency test. Forty metaphors of both types were presented to the participants during 10 sessions of instruction. To collect data on the learners' performance, a 30- item sentence completion test requiring 'word-given' and 'recognition' type responses was prepared and administered. The results of a statistical t-test indicated no significant difference in the rate of acquiring conceptual and image metaphors (P>.05). Therefore, both metaphors can be successfully taught concurrently with little difficulty.

Permeability mapping in porous media by magnetization prepared centric-scan SPRITE

The ability of porous media to transmit fluids is commonly referred to as permeability. The concept of permeability is central for hydrocarbon recovery from petroleum reservoirs and for studies of groundwater flow in aquifers. Spatially resolved measurements of permeability are of great significance for fluid dynamics studies. A convenient concept of local Darcy’s law is suggested for parallel flow systems. The product of porosity and mean velocity images in the plane across the average flow direction is directly proportional to permeability. Single Point Ramped Imaging with T 1 Enhancement (SPRITE) permits reliable quantification of local fluid content and flow in porous media. It is particularly advantageous for reservoir rocks characterized by fast magnetic relaxation of a saturating fluid. Velocity encoding using the Cotts pulsed field gradient scheme improves the accuracy of measured flow parameters. The method is illustrated through measurements of 2D permeability maps in a capillary bundle, glass bead packs and composite sandstone samples.

Expropriation of "old order" mineral rights in South Africa: the Constitutional Court has its say (twice)

The Mineral and Petroleum Resources Development Act 28 of 2002 (ZA) (MPRDA) makes provision for the conversion of so-called “old order” rights to prospecting and mining rights. The consequences of the failure of holders of old order rights to apply for (a) Conversion or (b) new rights under different circumstances were decided by the South African Constitutional Court in two decisions during 2013. These cases are discussed against the background of the nature, content and termination of old order rights. It is also discussed whether such rights were expropriated by the MPRDA and, if so, whether compensation is payable by the state.

Scalable production of wrinkled and few-layered graphene sheets and their use for oil and organic solvent absorption

High-quality wrinkled and few-layered graphene sheets have been produced via a mechano-thermal exfoliation process for a simple, effective and low-cost mass production. Graphene sheets were produced by first ball milling of graphite with ammonium chloride followed by thermal annealing at 800 °C in nitrogen gas. The few layered graphene sheets show highly efficient selectivity and capacity for the absorption of petroleum products as well as organic solvents such as ethanol, cyclohexane and chloroform (up to 82, 42 and 98 times of their own weight, respectively). The saturated few-layered graphene sheets can be cleaned for reuse by simply burning in air. The low-cost strategy for mass production and easy recycling routes demonstrate the great potential of few-layered graphene sheets for oil removal.

A tale of two expropriations: Newcrestia and Agrizania

A comparison will be made between the decision of the High Court of Australia in Newcrest Mining (WA) Ltd v The Commonwealth1 (“Newcrest”) and the decisions of the South African Courts in the Agri South Africa line of cases.2 Although the mineral law systems of the two countries differ insofar as historical development and content,3 the simplified facts of the Newcrest and Agri SA decisions and principles of expropriation law are similar enough to draw an interesting comparison between the respective cases. Both cases dealt with the issue of whether the mineral rights/mining rights of private holders were expropriated by legislation which prohibited mining in one way or another. A comparison between the cases shows the approaches towards the issues and what exactly constitutes deprivation and/or acquisition of property for purposes of expropriation and whether deprivation and/or acquisition actually took place.The differences between the mineral law systems of Australia and South Africa (before the enactment of the Mineral and Petroleum Resources Development Act 28 of 2002 (hereafter “MPRDA”)) and the protection afforded against the resumption/expropriation of mineral rights or mining rights will be set as background information for a better understanding of the respective decisions. The facts of the two cases will first be set out and simplified for comparative purposes before the respective decisions are discussed. At the end, a comparison will be made between the decisions and a conclusion reached about the similarity of principles and the correctness of the respective decisions.

Oil-spill cleanup: the influence of acetylated curaua fibers on the oil-removal capability of magnetic composites

A magnetic resin based on cardanol, furfural, and curaua fibers was prepared and characterized. The material could be used in oil-spill cleanup processes, because of its aromatic/aliphatic balance. The resin was prepared through bulk polycondensation of cardanol and furfural in the presence of curaua fibers and maghemite nanoparticles. Hydrophobicity of the curaua fibers was improved by acetylation, increasing the oil-absorbing capability of the composites. The obtained magnetic composites were studied by Fourier-transform infrared spectroscopy, X-ray diffraction, and thermogravimetric analysis. Degree of cure, magnetic force, and oil-removal capability tests were also performed. The results show that the composites possess an elevated cure degree in addition to a considerable magnetic force. The materials exhibit a good oil removal capability in the presence of a magnetic field, which is improved by the use of acetylated curaua. In the best case, the composite filled with maghemite and curaua can remove 12 parts of oil from water.

A preliminary study on machinability of super austenitic stainless steel

Stainless steel is the most widely used alloys of steel. The reputed variety of stainless steel having customised material properties as per the design requirements is Duplex Stainless Steel and Austenitic Stainless Steel. The Austenite Stainless Steel alloy has been developed further to be Super Austenitic Stainless Steel (SASS) by increasing the percentage of the alloying elements to form the half or more than the half of the material composition. SASS (Grade-AL-6XN) is an alloy steel containing high percentages of nickel (24%), molybdenum (6%) and chromium (21%). The chemical elements offer high degrees of corrosion resistance, toughness and stability in a large range of hostile environments like petroleum, marine and food processing industries. SASS is often used as a commercially viable substitute to high cost non-ferrous or non-metallic metals. The ability to machine steel effectively and efficiently is of utmost importance in the current competitive market. This paper is an attempt to evaluate the machinability of SASS which has been a classified material so far with very limited research conducted on it. Understanding the machinability of this alloy would assist in the effective forming of this material by metal cutting. The novelty of research associated with this is paper is reasonable taking into consideration the unknowns involved in machining SASS. The experimental design consists of conducting eight milling trials at combination of two different feed rates, 0.1 and 0.15 mm/tooth; cutting speeds, 100 and 150 m/min; Depth of Cut (DoC), 2 and 3 mm and coolant on for all the trials. The cutting tool has two inserts and therefore has two cutting edges. The trial sample is mounted on a dynamometer (type 9257B) to measure the cutting forces during the trials. The cutting force data obtained is later analyzed using DynaWare supplied by Kistler. The machined sample is subjected to surface roughness (Ra) measurement using a 3D optical surface profilometer (Alicona Infinite Focus). A comprehensive metallography process consisting of mounting, polishing and etching was conducted on a before and after machined sample in order to make a comparative analysis of the microstructural changes due to machining. The microstructural images were capture using a digital microscope. The microhardness test were conducted on a Vickers scale (Hv) using a Vickers microhardness tester. Initial bulk hardness testing conducted on the material show that the alloy is having a hardness of 83.4 HRb. This study expects an increase in hardness mostly due to work hardening may be due to phase transformation. The results obtained from the cutting trials are analyzed in order to judge the machinability of the material. Some of the criteria used for machinability evaluation are cutting force analysis, surface texture analysis, metallographic analysis and microhardness analysis. The methodology followed in each aspect of the investigation is similar to and inspired by similar research conducted on other materials. However, the novelty of this research is the investigation of various aspects of machinability and drawing comparisons between each other while attempting to justify each result obtained to the microstructural changes observed which influence the behaviour of the alloy. Due to the limited scope of the paper, machinability criteria such as chip morphology, Metal Removal Rate (MRR) and tool wear are not included in this paper. All aspects are then compared and the optimum machining parameters are justified with a scope for future investigations