Passivation of pigment-grade TiO(2) particles by nanothick atomic layer deposited SiO(2) films

Pigment-grade TiO(2) particles were passivated using nanothick insulating films fabricated by atomic layer deposition (ALD). Conformal SiO(2) and Al(2)O(3) layers were coated onto anatase and rutile powders in a fluidized bed reactor. SiO(2) films were deposited using tris-dimethylaminosilane (TDMAS) and H(2)O(2) at 500?°C. Trimethylaluminum and water were used as precursors for Al(2)O(3) ALD at 177?°C. The photocatalytic activity of anatase pigment-grade TiO(2) was decreased by 98% after the deposition of 2?nm SiO(2) films. H(2)SO(4) digest tests were performed to exhibit the pinhole-free nature of the coatings and the TiO(2) digest rate was 40 times faster for uncoated TiO(2) than SiO(2) coated over a 24?h period. Mass spectrometry was used to monitor reaction progress and allowed for dosing time optimization. These results demonstrate that the TDMAS-H(2)O(2) chemistry can deposit high quality, fully dense SiO(2) films on high radius of curvature substrates. Particle ALD is a viable passivation method for pigment-grade TiO(2) particles.     

Malnutrition in South Asia—A Critical Reappraisal

Malnutrition continues to be a major public health challenge especially in South Asian developing countries. The aim of the present review is to spotlight the magnitude of the prevalence of malnutrition and its dynamics in South Asian region and to suggest potential approaches for the prevention and control of this issue of public health significance. An extensive review of literature, covering malnutrition and its determinants, health and economic consequences and pragmatic preventive strategies was performed on computer based bibliographic databases (PubMed, Google Scholar, Scopus, Medline and Sciencedirect.com) to retrieve abstracts and full texts for India, Pakistan, Bangladesh, Sri Lanka and Nepal. All relevant titles and abstracts were examined and evaluated for malnutrition and its prevalence in South Asia. The results revealed malnutrition to be a major public health problem and a potential cause of high disease burden and mortality in South Asia. Compelling evidence suggests malnutrition to be the leading cause of stunting, wasting and underweight with drastic economic consequences among vulnerable populations. Reduced cognitive performance and low productivity have also been associated with micronutrients malnutrition. Suboptimal breastfeeding, inadequate food supply, micronutrient deficiencies, low household income, poor health care system, increased healthcare costs, illiteracy, unhygienic and substandard living, inappropriate child's care and the caregiver, food insecurity and on top of that vicious cycle of poverty, have been recognized as principal indicators for growing malnutrition prevalence in South Asia. Global organizations, local governments, program managers, NGOs, academia, industry in particular and the society at large need to take up the challenge to completely confiscate malnutrition from the region for economic prosperity and a healthier future.     

Structural,rheological, and mechanical properties of ternary blends of PEN,PET, and liquid crystalline polymer

Structural, rheological, and mechanical properties of ternary blends of a liquid crystalline copolyester (LCP) composed of p-hydroxybenzoic acid and 2,6-hydroxynaphthoic acid, poly(ehtylene naphthalate)(PEN), and poly(ethylene terephtalate) (PET) were investigated using capillary rheometry, tensile testing, scanning electron microscopy, and X-ray diffraction. Viscosity-shear rate behavior of the ternary blends is very similar to that of pure polymers and their binary blends. The activation energy of flows of the ternary blends was smaller than those of PEN and PET. Tensile modulus and strength of extruded strands of the blends increased with increasing LCP content. The extruded strands of the blends consist of a crystalline and oriented LCP phase and an amorphous and unoriented PEN/PET blended phase. Tensile mechanical properties and structures of the ternary blends were discussed.     

Influence and comparison of emerging techniques of yarn manufacturing on physical–mechanical properties of polyester-/cotton-blended yarns and their woven fabrics

Abstract

In this study, the physical–mechanical properties of ring spun, ring compact, rotor and air-vortex yarns were investigated. The study was carried with yarn having linear densities of 24.4 tex and 36.7 tex, which were then converted to woven fabrics. The ring spun yarns have higher values of strength but also with higher strength irregularities. Extra-ordinarily low hairiness was observed in air-vortex yarns due to its unique yarn formation technique. The deviation rate (DR) of yarns have correlation with the mass spectrogram of respective yarns obtained from USTER Tester 5. Rotor and air-vortex yarns exhibited higher coefficient of friction. The woven fabrics made from ring spun yarns exhibited higher tensile and tear strength with higher elongation at break. The fabrics made from air-vortex yarns have very good pilling grade due to less protruding fibres on their surface and good structural integrity.     

Dietary Pigmentation and Deposition of α-Tocopherol and Carotenoids in Rainbow Trout Muscle and Liver Tissue

Rainbow trout (Oncorhynchus mykiss) were fed diets supplemented with canthaxanthin, oleoresin paprika and α-tocopherol. Canthaxanthin was more efficiently absorbed (3.8–7.9 mg/kg) in the flesh of rainbow trout than the paprika carotenoids (2.4–3.1 mg/kg). With increased pigmentation, decrease in lightness (L*) and hue angle, and increase in redness (a*) of the muscle were observed. Canthaxanthin produced more desirable reddish-pink color. Deposition of α-tocopherol in liver and muscle tissue increased with increase in dietary α-tocopheryl acetate. Fish receiving lower α-tocopheryl acetate reached maximum deposition levels earlier than those fed higher levels. There was no effect of α-tocopherol and carotenoid levels on muscle fatty acid composition.     

Tool wear mechanisms in the machining of Nickel based super-alloys: A review

Nickel based super-alloys are widely employed in aircraft engines and gas turbines due to their high temperature strength, corrosion resistance and, excellent thermal fatigue properties. Conversely, these alloys are very difficult to machine and cause rapid wear of the cutting tool, frequent tool changes are thus required resulting in low economy of the machining process. This study provides a detailed review of the tool wear mechanism in the machining of nickel based super-alloys. Typical tool wear mechanisms found by different researchers are analyzed in order to find out the most prevalent wear mechanism affecting the tool life. The review of existing works has revealed interesting findings about the tool wear mechanisms in the machining of these alloys. Adhesion wear is found to be the main phenomenon leading to the cutting tool wear in this study.     

A new hybrid approach for the solution of nonconvex economic dispatch problem with valve-point effects

Economic dispatch (ED) generally formulated as convex problem using optimization techniques by approximating generator input/output characteristic curves of monotonically increasing nature results in an inaccurate dispatch. The genetic algorithm has previously been used for the solution of problem for economic dispatch but takes longer time to converge to near optimal results. The hybrid approach is one of the methodologies used to fine tune the near optimal results produced by GA. This paper proposes new hybrid approach to solve the ED problem by using the valve-point effect. The approach we propose combines the genetic algorithm (GA) with active power optimization (APO) based on the Newton's second order approach (NSO). The genetic algorithm acts as a global optimizer giving near optimal generation schedule, which becomes the input for generation buses in APO algorithm. This algorithm acting as local search technique dispatching the generated active power of units for minimization of cost and gives optimum generation schedule. Three machines 6-bus, IEEE 5-machines 14-bus, and IEEE 6-mchines 30-bus systems have been tested for validation of our approach. Results of the proposed scheme compared with results obtained from GA alone give significant improvements in the generation cost showing the promise of the proposed approach.     

Effect of absorption of solar radiation in glass-cover(s) on heat transfer coefficients in upward heat flow in single and double glazed flat-plate collectors

Absorption of solar radiation in the glass cover(s) of a flat plate solar collector increases the temperature of cover(s) and hence changes the values of convective and radiative heat transfer coefficients. The governing equations for the case of single as well as double glazed collector have been solved for inner and outer surface temperatures of glass cover(s) with/without including the effect of absorption of solar radiation in the glass cover(s), with appropriate boundary conditions. The effects of absorption of solar radiation on inner and outer surface temperatures and consequently on convective and radiative heat transfer coefficients have been studied over a wide range of the independent variables. The values of glass cover temperatures obtained from numerical solutions of heat balance equations with and without including the effect of absorption of solar radiation in the glass cover(s) are compared. For a single glazed collector the increase in glass cover temperature due to absorption of solar radiation could be as high as 6°. The increase in temperatures of first and second glass covers of a double glazed collector could be as high as 14° and 11°, respectively. The effect on the convective heat transfer coefficient between the absorber plate and the first glass cover is substantial. The difference in the values of the convective heat transfer coefficients between the absorber plate and the first glass cover (h_cp1) of a double glazed collector for the two cases: (i) including the effect of absorption and (ii) neglecting the effect of absorption in glass cover, could be as high as 49%. Correlations for computing the temperatures of inner and outer surfaces of the glass cover(s) of single and double glazed flat plate collectors are developed. The relations developed enable incorporation of the effect of absorption of solar radiation in glass cover(s) in the relations for inner and outer surface temperatures in a simple manner. By making use of the relations developed for inner and outer surface temperatures of glass cover(s) the convective and radiative heat transfer coefficients can be calculated so close to those obtained by making use of surface temperatures of glass cover(s) obtained by numerical solutions of heat balance equations that numerical solutions of heat balance equations are not required.     

Influence of Melt-Spinning Parameters on the Structure and Soft Magnetic Properties of (Fe0.65Co0.35)88Zr7B4Cu1 Alloy

Melt-spun ribbons of (Fe_0.65Co_0.35)₈₈Zr₇B₄Cu₁ alloy have been prepared at different wheel speeds, namely, 47, 39, 34, and 17 m/s, and subsequently annealed at 773 K (500 °C) under controlled atmosphere. Structural and soft magnetic properties have been evaluated using X-ray diffraction, differential scanning calorimetry, transmission electron microscopy, and vibrating sample magnetometer. The structure of as-spun ribbons changes from fully amorphous to partially amorphous/nanocrystalline to fully nanocrystalline (bcc α-Fe(Co) + Fe₂Zr) on decreasing the wheel speed. Annealing of amorphous ribbons leads to the precipitation of nanocrystalline bcc α-Fe(Co) phase. The Curie temperature (T _c ) of the amorphous phase is found to increase with decreasing wheel speed possibly due to the effect of exchange field penetration of nanocrystals present in the amorphous matrix. The saturation magnetization (4πM _s ) of as-spun ribbons having partially nanocrystalline bcc α-Fe(Co) phase is high as compared to the ribbons with completely amorphous phase, and it remains almost the same even after annealing. The lowest coercivity has been achieved in the ribbons that are fully amorphous, and the coercivity was found to increase with decreasing wheel speed.