Effect of alloying on the electronic structure and magnetic properties of Fe,Co and Ni with Au and Ag

We use the self-consistent, augmented space recursion technique to study the electronic structure and magnetic properties of alloys of the transition metals, Fe, Co and Ni with the noble metals, Ag and Au. We analyse the effect of local environment and the hybridization between the constituent bands on the electronic and magnetic properties.     

Synthesis of poly(methylmethacrylate)/montmorillonite nanocomposites via in situ intercalative suspension and emulsion polymerization

Summary Na-montmorillonite (MMT) with cation exchange capacity (CEC) of 90 mEq/100g was converted to MMT-CTAB and MMT-CPC forms by the intercalation of Cetyltrimethylammonium bromide (CTAB) and Cetylpyridinium chloride (CPC), respectively. The intercalation of these surfactants onto the basal space of the montmorillonite was evidenced by fourier transform infrared spectroscopy (FTIR) and x-ray diffraction (XRD). The intercalation of the CPC expanded the basal space from 12.19 A^o to 21.47 A^o while in case of CTAB it was expanded to 19.35 A^o only. The (MMT-CPC) was subsequently used as a host for the preparation of PMMA nanocomposites via intercalative suspension and emulsion polymerization of methylmethacrylate (MMA) using benzoyl peroxide (BPO) and potassium persulphate (PPS) individually and simultaneously. The use of BPO and PPS together invoked better exfoliation but the yield did not change appreciably in comparison with using either of the initiators alone. Different structures were obtained with the variation of the preparation conditions; exfoliated and intercalated nanocomposites which were characterized by XRD, transmission electron microscope (TEM), thermal gravimetric analysis (TGA), and differential scanning calorimeter (DSC). The resultant nanocomposites exhibited improved thermal stability relative to the equivalent macrocomposites. No glass transition temperature (Tg) could be detected for the prepared nanocomposites which was assumed to result from the restricted molecular motion of the polymer chains.     

Surface modification of Hastelloy C-276 by SiC addition and electron beam melting

Electron beam surface melting of Hastelloy C-276 with the SiC addition is carried out to improve the surface properties. The resulted microstructure and non-equilibrium phases are characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and energy dispersive system (EDS). The Hastelloy C-276 is successfully surface-hardened by electron beam melting, the surface hardening effect can be attributed to both microstructure refinement and eutectic phases produced by EB. During EB melting the SiC broke into small pieces and spread in the microstructure increasing the surface hardness by thirteen times.     

Comparison of the performance of selected powder and masterbatch pigments on mechanical properties of mass coloured polypropylene filaments

No suitable method for the coloration of unmodified polypropylene using aqueous dye solution has yet been found. Currently, the only viable method is the incorporation of pigments during the extrusion of filaments. In this study, two different commercially available forms of pigment (powder and masterbatch) were incorporated into polypropylene before extruding into filaments to examine their effects on the mechanical behaviour of the filaments. It was found that increasing the pigment content generally reduces tensile strength and Young's modulus in both masterbatch-pigmented filaments and powder-pigmented filaments. However, the extent of reduction is also markedly dependent on the type of pigment incorporated. In addition, elongation to peak is much higher for masterbatch-pigmented filaments than for powder-pigmented filaments.     

Triple therapy in duodenal ulcer healing--a follow up study

Thirty-nine Helicobacter pylori (HP) positive chronic duodenal ulcer patients completed the 4 weeks treatment of triple therapy (Denol, Metronidazole and Amoxil). Of these 29 showed healed duodenal ulcer and negative CLO test at 8 weeks (eradication). They were followed at 3,6 and 12 months and at each follow-up, endoscopy and CLO testing were repeated. At 12 weeks, 54% showed a healed ulcer and negative CLO and these figures reached to 69 and 66% at 6 and 12 months respectively. Thirty percent relapsed within 1 year. The present study indicates a prolonged remission of duodenal ulcer following HP eradication.     

Non-intubated pyeloplasty for pelviureteric junction obstruction in children

Sixty-one consecutive patients undergoing pyeloplasty (5 bilateral) were reviewed retrospectively; 54 pyeloplasties were non-intubated (NIP) and 12 were intubated. NIPs were managed by an extrarenal wound drain, which was removed after 2-4 days in 44 repairs with minimal or no urinary leakage and after 6-8 days in 10 with significant leakage. Fifty-two were successful after the primary procedure. One patient who developed a urinoma after drain removal required a percutaneous nephrostomy followed by a revision pyeloplasty. A second revision pyeloplasty was necessary for persistent postoperative obstruction. The results of NIP compared favorably with series where intubation was used routinely and were superior to alternative methods of management such as endopyelotomy.     

Testing of highly loaded horizontal axis wind turbines designed for optimum performance

The realization of a wind turbine as a source of clean, non-polluting and renewable energy may depend on the optimum design of turbine blades that can operate efficiently under extreme variations in wind conditions. In this paper we provide results of an experimental investigation to examine the effectiveness of a highly loaded theory for the design of a horizontal axis wind turbine for optimum power production over a wide range of advance ratios. We find the theory, which can be used to set up design curves easily and requires only hand held calculator for calculation, offers a rational basis for the design of propeller wind turbines for peak performance.     

Effect of Simulated Gastrointestinal Conditions on Drug Release from Pectin/Ethylcellulose as Film Coating for Drug Delivery to the Colon

The aim of this work was to investigate the effect of acidic pH representative of gastric fluid on the release of 5-aminosalicylic acid from beads coated with pectin/ethylcellulose as film coating intended for drug delivery to the colon, in media mimicking the lower gastrointestinal (GI) tract and representative of colonic conditions. In this work, the in vitro incubation of the beads in acid medium was found to influence the hydration and the swelling characteristics of pectin after transfer into simulated intestinal fluid and simulated cecal fluid containing pectinolytic enzymes. Moreover, the drug release profiles from the beads in simulated intestinal fluid after incubation for 2 h or 30 min in simulated gastric fluid vs. no acid incubation were found to be very different. The in vitro degradation of pectin in the coat by pectinolytic enzymes in simulated cecal fluid depended on whether the beads were placed in simulated gastric fluid prior to testing in simulated intestinal fluid. The percentage drug release also depended on the ratio of pectin to ethylcellulose in the coat.     

The Time Dependence of the Detachment Force of Ground Micrometer-Size Particles from a Planar Substrate: Effect of Particle Rotation

The time dependence of the detachment force applied to 7 µm ground polyester particles coated with silica nanoparticles was determined by ultracentrifugation. It was found that the force required to separate the particles from the substrate increased during the first 24 hours and changed very little thereafter. Scanning electron microscopy (SEM) results suggest that the increase in adhesion is due to the particles rotating from their initial positions obtained during deposition. The role of the silica nanoparticles in determining the time dependence of the detachment force is discussed in terms of the JKR and Fuller-Tabor models.     

Biochemical studies on combined effects of garlic (Allium sativum Linn) and ginger (Zingiber officinale Rosc) in albino rats

Adult male rats of wistar strain were fed diets containing (w/w) 2% garlic (group II), 0.5% ginger (group III) and a combination of garlic plus ginger (group IV) for 4 weeks to study their effects on serum biochemical parameters. A significant increase in body weight was observed in all groups except that fed ginger (group III). A significant decrease in blood glucose, serum total cholesterol and serum alkaline phosphatase were found in all groups, whereas serum triglycerides were decreased significantly only in group IV. Serum HDL-cholesterol was significantly increased only in groups III and IV. However, HDL-cholesterol, VLDL-cholesterol and atherogenic index were significantly decreased in animals fed with combination of the two, compared to garlic/ginger alone. Hence, a combination of garlic and ginger is much more effective in reducing blood glucose and serum lipids.