Abrasive wear studies on composites of PEEK and PES with modified surface of carbon fabric

Carbon fabric (CF) being inert towards the matrix, the quality of its adhesion with the matrix is poor and hence, needs treatment to enhance fiber-matrix bonding. In this paper, cold remote nitrogen oxygen plasma (CRNOP) treatment to CF was employed to improve fiber-matrix adhesion. Composites were developed using CF with polyethersulphone (PES) and polyetheretherketone (PEEK) matrices. Performance enhancement due to CF treatment was quantified by improvement in mechanical and wear resistance (W_R) properties. A fairly good linearity was observed for specific wear rate (K₀×ILSS) as a function of a factor (μP/E).     

Anaesthetic management of a morbidly obese patient

Morbid Obesity (MO) is associated with various pathophysiological changes which affect the outcome of anaesthesia and surgery. We report here anaesthetic management of a fit morbidly obese patient for transcervical resection of endometrium (TCRE) under spinal subarachnoid block. The preoperative preparation, intraoperative and postoperative management is described and the various problems in morbidly obese patients are discussed.     

Aggregation Behavior of Task-Specific Acidic Ionic Liquid N-Methyl-2-Pyrrolidinium Dihydrogen Phosphate [NMP][H2PO4] in Aqueous and Aqueous Salt Solutions

The effect of alkali salt (NaCl, NaBr, and KCl) addition on aggregate formation of N-methyl-2-pyrrolidinium dihydrogen phosphate [NMP][H₂PO₄] ionic liquid in aqueous solution was determined using surface tension at 298.15K and conductance from 288.15 to 308.15K. The surface parameters such as critical aggregation concentration (CAC), adsorption efficiency, surface pressure, surface tension at CAC, minimum surface cover by a single molecule, and maximum area excess concentration were calculated from surface tension measurements with and without salts. The results show that [NMP][H₂PO₄] forms aggregates at lower concentrations and is more surface active than classical cationic surfactants.     

Thermal coupling links to liquid‐only transfer streams: A path for new dividing wall columns

We propose new dividing wall columns (DWCs) that are equivalent to the fully thermally coupled (FTC) configurations. While our method can draw such configurations for any given n‐component mixture (n ≥ 3), we discuss in detail the DWCs for ternary and quaternary feed mixtures. A special feature of all the new DWCs is that during operation, they allow independent control of the vapor flow rate in each partitioned zone of the DWC by means that are external to the column. Because of this feature, we believe that the new arrangements presented in this work will enable the FTC configuration to be successfully implemented and optimally operated as a DWC in an industrial setting for any number of components. Also, interesting column arrangements result when a new DWC drawn for an n‐component mixture is adapted for the distillation of a mixture containing more than n components. © 2014 American Institute of Chemical Engineers AIChE J, 60: 2949–2961, 2014     

High-Tc superconductors: New insights from angle-resolved photoemission

Recent angle-resolved photoemission (ARPES) studies of the high-T _c superconductors by the Argonne group are briefly reviewed. First we discuss sum rules to establish a spectral function interpretation of the data, and the use of ARPES to obtain the momentum distribution. We then apply these ideas to the normal and superconducting state spectra for B₂Sr₂Cu₂O₈. Among the topics discussed are the Fermi surface, polarization selection rules, bilayer splitting, and the superconducting gap.     

Profit analysis of a one-server one-unit system with partial failure subject to random inspection

This paper deals with the cost-benefit analysis of a single-server one-unit system with partial failure, which is subject to random inspection. An inspection policy model is considered in which the partial failure of the unit is detected only by inspection, but complete failure of the unit is detected instantaneously without inspection. The system is observed at suitable regenerative epochs in order to obtain several economics-related system characteristics. Explicit results are obtained in a few particular cases. Graphs are also given.     

Social housing programme of Selangor <Emphasis Type="Italic">Zakat</Emphasis> Board of Malaysia and housing satisfaction

Social housing in Malaysia is provided through the public and private sectors. Recently, the Selangor Zakat Board (SZB) has started to provide social housing in the state of Selangor, Malaysia. Up to 2007, a total of 906 units have been delivered under its different programmes. This paper evaluates these programmes by adopting the housing satisfaction model which is currently used as a customer satisfaction tool for public/private housing in many local governments in the UK and USA. The main purpose of this paper is to identify the types of housing programmes adopted by SZB and examine beneficiaries’ housing satisfaction in each programme on a comparative plane. In order to examine housing satisfaction, five objective components of satisfaction—housing unit features, housing unit support services, the social environment, public facilities and neighbourhood facilities—were analysed through beneficiaries’ levels of satisfaction which were measured by applying a Likert scale. The findings of the paper indicate that SZB has been successful in providing a moderate level of satisfaction with the housing unit. However, the existence of variable levels of satisfaction with other components implies that there is still scope to enhance residents’ satisfaction with those components.     

Bilayer Suspension Plasma-Sprayed Thermal Barrier Coatings with Enhanced Thermal Cyclic Lifetime: Experiments and Modeling

Suspension plasma spraying (SPS) has been shown as a promising process to produce porous columnar strain tolerant coatings for thermal barrier coatings (TBCs) in gas turbine engines. However, the highly porous structure is vulnerable to crack propagation, especially near the topcoat-bondcoat interface where high stresses are generated due to thermal cycling. A topcoat layer with high toughness near the topcoat-bondcoat interface could be beneficial to enhance thermal cyclic lifetime of SPS TBCs. In this work, a bilayer coating system consisting of first a dense layer near the topcoat-bondcoat interface followed by a porous columnar layer was fabricated by SPS using Yttria-stabilised zirconia suspension. The objective of this work was to investigate if the bilayer topcoat architecture could enhance the thermal cyclic lifetime of SPS TBCs through experiments and to understand the effect of the column gaps/vertical cracks and the dense layer on the generated stresses in the TBC during thermal cyclic loading through finite element modeling. The experimental results show that the bilayer TBC had significantly higher lifetime than the single-layer TBC. The modeling results show that the dense layer and vertical cracks are beneficial as they reduce the thermally induced stresses which thus increase the lifetime.     

Transplantation of nano-bioglass/gelatin scaffold in a non-autogenous setting for bone regeneration in a rabbit ulna

Bioactive glass has been investigated for variety of tissue engineering applications. In this study, fabrication, in vitro and in vivo evaluation of bioactive glass nanocomposite scaffold were investigated. The nanocomposite scaffolds with compositions based on gelatin and bioactive glass nanoparticles were prepared. The apatite formation at the surface of the nanocomposite samples confirmed by Fourier transform infrared spectroscopy, scanning electron microscopy and X-ray powder diffraction analyses. The in vitro characteristics of bioactive glass scaffold as well as the in vivo bone formation capacity of the bioactive glass scaffold in rabbit ulnar model were investigated. The bioactive glass scaffold showed no cytotoxicity effects in vitro. The nanocomposite scaffold made from gelatin and bioactive glass nanoparticles could be deliberated as an extremely bioactive and prospective bone tissue engineering implant. Bioactive glass scaffolds were capable of guiding bone formation in a rabbit ulnar critical-sized-defect model. Radiographic evaluation indicated that successful bridging of the critical-sized defect on the sides both next to and away from the radius took place using bioactive glass scaffolds. X-ray analysis also proposed that bioactive glass scaffolds supported normal bone formation via intramembranous formation     

Size-tunable nanoparticles composed of dextran-b-poly(D,L-lactide) for drug delivery applications

Nanoparticles (NPs) formulated using self-assembly of block copolymers have attracted significant attention as nano-scaled drug delivery vehicles. Here we report the development of a biodegradable NP using self-assembly of a linear amphiphilic block copolymer, Dex-b-PLA, composed of poly(D,L-lactide), and dextran. The size of the NPs can be precisely tuned between 15 and 70 nm by altering the molecular weight (M _W) of the two polymer chains. Using doxorubicin as a model drug, we demonstrated that the NPs can carry up to 21% (w/w) of the drug payload. The release profile of doxorubicin from NPs showed sustained release for over 6 days. Using a rat model, we explored the pharmacokinetics profiles of Dex-b-PLA NPs, and showed proof-of-concept that long circulation lifetime of the NPs can be achieved by tuning the M _W of Dex-b-PLA block copolymer. While the terminal half-life of Dex-b-PLA NPs (29.8 h) was similar to that observed in poly(ethylene glycol)-coated (PEG-coated) NPs (27.0 h), 90% of the injected Dex-b-PLA NPs were retained in the blood circulation for 38.3 h after injection, almost eight times longer than the PEG-coated NPs. The area under curve (AUC) of Dex-b-PLA NPs was almost four times higher than PEG-based NPs. The biodistribution study showed lower accumulation of Dex-b-PLA NPs in the spleen with 19.5% initial dose per gram tissue (IDGT) after 24 h compared to PEG-coated poly(lactide-co-glycolide) (PLGA) NPs (29.8% IDGT). These studies show that Dex-b-PLA block copolymer is a promising new biomaterial for making controlled nanoparticles as drug delivery vehicles.