84 research outputs found

    Doing Business in China: A Risk Analysis

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    The aim of this research is to describe the various challenges faced by western companies that plan to do business in China. In specific this document aims to explore (I) The challenges for a Western company that wishes to outsource production to China, (II) The challenges for western companies that plan to sell their products in the Chinese market and (III) The key differences and similarities in the above mentioned scenarios

    Adsorption and Wetting in Model Mesoporous Silicas and in Complex Metal Oxide Catalysts

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    The surface of most metal oxides is covered by hydroxyl groups which influence many surface phenomena such as adsorption and wetting, catalysis and surface reactions. Surface chemistry of silica is a subject of exhaustive studies owing to a wide variety of practical applications of silica. In Chapter 1, a brief review of classification, synthesis and characterization of silica is provided. The hydroxylation of silica surface i.e the number of hydroxyl (-OH) groups on the surface is of utmost importance for its practical applications. In Chapter 2, a brief introduction to surface hydration of silica is provided followed by the gas adsorption measurements and characterization. Pore wetting is critical to many applications of mesoporous adsorbents, catalysts, and separation materials. In the work presented in Chapter 3, we employed the combined vapor adsorption study using nitrogen (77K) and water (293K) isotherms to evaluate the water contact angles for a series of ordered mesoporous silicas (ex:SBA-15). The proposed method of contact angle relies on the statistical film thickness (t-curve) of the adsorbed water. There were no t-curves for water for dehydroxylated or hydrophobic surfaces in literature and we addressed this issue by measuring t-curves for a series of model surfaces with known and varying silanol coverage. Using the radius of menisci ((2)), statistical film thickness t(H2O) from water isotherm, and the true radius of pores ((2)), from nitrogen isotherms, the water contact angle inside pores were calculated. As it was anticipated, the results obtained showed that the silica pore contact angles were strongly influenced by the number of the surface silanol groups and, therefore, by the thermal and hydration treatments of silicas. Phthalocyanines (Pcs) present an interesting class of catalytically active of molecules with unique spectroscopic, photoelectric, and sometimes magnetic properties. In the work presented in Chapter 4, we have undertaken a systematic study to explore the possibility of preparing a supported catalyst material i.e loading fluorinated metal phthalocyanines onto metal oxide surfaces by two other techniques in addition to solution adsorption. Techniques or procedures that have been used to immobilize MPcs include: i) physical adsorption (from solution) onto metal oxide surface, ii) deposition by pore filling and encapsulation and iii) mesopore entrapment or confinement. The MPcs are loaded on to metal oxides with an aim to: a) maximize the surface area of the Pcs by distributing it over the support, b) immobilize the Pcs so that they do not leach into the solution environment, c) improve the thermal stability of the Pcs and d) attempt to achieve single-site catalysis. All the immobilization techniques were carried out with F64PcZn as the model MPc, acetone as the immobilization solvent and silica or alumina as adsorbents (solid support). An understanding of gas adsorption mechanisms on metal phthalocyanines (MPcs) is essential for their practical application in biological processes, gas sensing, and catalysis. In this work, the surface characteristics were probed by performing nitrogen and water adsorption on the free-form MPcs (without immobilization on solid support) and characterization of their physical properties. The combined vapor adsorption study (developed in Chapter 3) enabled in understanding the affinity of Pcs towards water vapor i.e number of water molecules adsorbed per phthalocyanine molecule was obtained. This information is very relevant towards using Pcs as catalyst since water vapor is guaranteed to be present in most of the catalytic reaction environment

    Making Sense Of Software Ecosystems: A Critical Review

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    Visualizing software as ecosystems has been an emergent phenomenon. The objective of this paper is to analyze the field of software ecosystems (SECO) and provide a critical review of the existing literature. This research identifies domains and peripheries of a SECO; highlights architectural challenges; examines design and control mechanisms and discusses some of the learning’s from other popular paradigms that can be applied to address the key challenges in the SECO paradigm. This paper also aims to recommend future research directions for software ecosystems and its role in the broader context of information systems research

    SOLVENT BEHAVIOR IN HYDROPHOBIC SILICA NANOTUBES AND NANOTUBE MEMBRANES

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    The development of template-synthesized silica nanotubes has created a unique opportunity for studying confined fluids by providing nanometer-scale containers in which, the inner diameter (i.d.) and surface chemistry can be systematically and independently varied. An interesting question to be answered is: Do solvents wet nanometer-scale tubes in the same way that they wet ordinary capillaries? To answer this question, we have conducted studies to explore the wettability of the hydrophobic interiors of individual nanotubes. In these studies, single nanotubes with i.d.'s of either 30 or 170 nm were investigated over a range of water/methanol mixtures. These studies provide a direct route for comparing wetting phenomena in nanotubes with conventional macroscopic theories of capillarity. Our observations reveal four important aspects of wetting in the sub-200 nm regime; (i) observation of a sharp transition between wetting and non-wetting conditions with increasing methanol concentration, (ii) invariance of this transition between nanotubes of 30 and 170 nm pore diameter (iii) failure of the Young-Laplace equation to accurately predict the methanol mole fraction for the transition and (iv) the reversibility of the observed wetting. The single nanotube measurements were complemented with membrane transport experiments that corroborate our conclusions. The first two aspects conform to conventional capillarity (Young-Laplace), but the latter two do not. The variation between the predicted and the experimental values may be associated with either our reliance on macroscopic values of contact angles and surface tensions in the Young-Laplace equation, or to liquid phase instability within the hydrophobic pore

    A Four-Transistor Level Converter for Dual-Voltage Low-Power Design

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    Power dissipation in digital circuits has become a primary concern in electronic design. With increasing usage of portable devices, there are severe restrictions being placed on the size, weight and power of batteries. In this work, we propose a design of a dual V th feedback type four-transistor level converter (DVF4) with reduced delay and power overheads. The use of DVF4 enhances the effectiveness of a dual-voltage low-power design. The level converter can be used in a circuit with multi supply voltage system where low supply gates may feed into high supply gates resulting in lower power and higher speed than with previously published level converters. The proposed level converter is based on a feedback circuit and employs multi-V th technique. To portray the advantages, we compare the proposed level converter with a previously published level converter for various supply voltages and observe 17.44% to 53% power savings and around 50% delay reduction over the best 32 nm CMOS design available in the literature. The impact of process variations is also examined. When used with dual VDD designs, the new level converter renders up to 61% more energy savings for benchmark circuits in comparison when level converters are not allowed. Furthermore, a level converter flip-flop combination performs better than an existing level converting flip-flop. A single-threshold alternative of the new level converter still remains effective, though over a reduced voltage range

    Association of ACE Polymorphism and Diabetic Nephropathy in South Indian Patients

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    Objective: To study the association of ACE gene polymorphism and diabetic nephropathy in South Indian subjects. Setting: Outpatient clinic of a specialized hospital. Patients: The study included 109 South Indian type 2 diabetic patients (72 males and 37 females; age 56.7±9.0 years, mean±SD). The patients were subdivided into two groups: nephropathic (n=86) and normoalbuminuric patients (n=23). Interventions: Genomic DNA was isolated from the peripheral blood leukocytes. To determine the ACE genotype, genomic DNA was amplified by PCR initially using a flanking primer pair and, subsequently when necessary, with a primer pair that recognizes the insertion specific sequence for confirmation of the specificity of the amplification reactions. Main outcome measures: ACE genotype distribution in the two study groups. Results: In the nephropathic patients, ID and DD genotypes were present in 52.3% and 27.9% of the patients, respectively as compared to 34.8% and 21.7% respectively in those with normoalbuminuria. The D allele was present in 80.2% of the nephropathic patients and 56.5% of the normoalbuminuric patients (c 2=4.28, P=0.039; odds ratio 3.12). Therefore, the higher percentage of II genotype in the normoalbuminuric group was 43.5% as compared to the 19.8% in nephropathic patients. Conclusions: This study showed a positive association between the D allele (ID and DD genotype) of the ACE polymorphism and diabetic proteinuria in South Indian type 2 diabetic patients. Our findings are in keeping with several earlier studies showing a strong association of the D allele of the ACE gene with diabetic nephropathy
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