Weighted Sum of Gray Gas Modeling for Nongray Radiation in Combusting Environment Using the Hybrid Solution Methodology

A hybrid solution approach is proposed to solve the radiation transfer equation (RTE) in combusting environment using the weighted sum of gray gases model for modeling the absorption coefficient. The hybrid approach uses a selective combination of the finite-volume method (FVM) and P1 approximation to solve the RTE for different gray gases. A comprehensive study with a wide range of test cases with homogenous and nonhomogenous media is carried out to study the accuracy, speed, and convergence rate of the hybrid solution approach. The differences between hybrid and FVM results are described, and the sources of errors are discussed.     

Development of an improved method of cultivation to obtain high biomass of the red alga Gelidiella acerosa (Gelidiales, Rhodophyta) in the open sea

This study describes a suspended stone (SS) method developed for in situ propagation of Gelidiella acerosa. The biomass yield potentials with various growth parameters were studied and compared to the floating raft method that was regarded as a superior method for Gelidiella propagation. The biomass of G. acerosa produced by the SS method consistently increased from the first to the fourth harvest (r = 0.940; P < 0.01) and ranged from 528 to 3645 g fresh wt m⁻². For the raft method biomass increased from the first to the third harvest (977-1288 g fresh wt m⁻²) and then decreased in the fourth harvest (953 g fresh wt m⁻²). The DGR values of the SS method increased exponentially (r = 0.865; P < 0.05) from the first to the fourth harvest (1.33-2.62%) and these values significantly differed from those obtained from the raft method in the second to fourth harvest (P < 0.001) but did not significantly differ in the first harvest (P > 0.05). The biomass of an individual plant harvested from the SS method was significantly higher (P < 0.001) than those obtained for the raft method at all four harvests. The frequency distribution of weight of an individual plant in the SS method also constantly increased in successive harvests and 5% of the plantings in the fourth harvest attained a biomass of 200-250 g fresh wt. The in situ propagation of this species through the SS method described in this study could be a viable option for conservation and large-scale farming in the sea.     

Momentum and Heat Transfer Phenomena for Power–Law Liquids in Assemblages of Solid Spheres of Moderate to Large Void Fractions

This work extends our previously reported results for the flow of and heat transfer from expanded beds of solid spheres to power–law fluids by using a modified and more accurate numerical solution procedure. Extensive results have been obtained to elucidate the effects of the Reynolds number (Re), the Prandtl number (Pr), the power–law index (n), and the bed voidage (ε) on the flow and heat transfer behavior of assemblages of solid spheres in the range of parameters: 1 ≤ Re ≤ 200, 1 ≤ Pr ≤ 1000, 0.6 ≤n ≤ 1.6, and 0.7 ≤ε ≤ 0.999999. The large values of bed voidage are included here to examine the behavior in the limit of an isolated sphere. As compared to Newtonian fluids, for fixed values of the Reynolds number and the voidage, the total drag coefficient decreases and the average Nusselt number increases for shear thinning fluids (n < 1); whereas, for shear thickening fluids (n > 1), the opposite behavior is observed. The drag results corresponding to bed voidage, ε = 0.99999, are very close to that of a single sphere; whereas, the heat transfer results approach this limit at ε = 0.999. Based on the present numerical results, simple correlations for drag coefficient and average Nusselt number are proposed which can be used to calculate the pressure drop for the flow of a power–law fluid through a bed of particles, or rate of sedimentation in hindered settling and the rate of heat transfer in assemblages of solid spheres in a new application. Broadly speaking, all else being equal, shear-thinning behavior promotes heat transfer, whereas shear-thickening behavior impedes it.     

Quantitation of microstructure of novolac resins: Development of improved one‐ and two‐dimensional NMR methodologies

The elucidation of the exact microstructure of polymers is always a challenging task. The range of molecular weights and uncontrolled polymerization leading to branching necessitates the development of better analytical methodologies. An improved methodology is presented for quantitatively estimating the microstructure of novolac resins and the percent incorporation of different monomers therein. An analysis is used that is based on the fully relaxed ¹H‐NMR spectrum in combination with the results of two‐dimensional heteronuclear single quantum correlation, double quantum filtered correlation spectroscopy, and total correlation spectroscopy. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 91: 2096–2102, 2004     

Designing of high-resolution photoresists: use of modern NMR techniques for evaluating lithographic performance

Applications of improved 1-D/ 2-D NMR spectroscopic techniques have been reviewed for quantitatively estimating the incorporation of different monomers and degree of linearity in resin microstructure. Comparison of the NMR data with those from lithography leads to a distinct correlation between resin micro-structure and lithographic performance. A novel photoresist mechanism is proposed in a positive photoresist; also, using modern NMR techniques, the crosslinking mechanism in a negative photoresist has been studied.     

Genotypic variation and relationships between quality traits and trace elements in traditional and improved rice (Oryza sativa L.) genotypes

In this study, we assessed the extent of genotypic differences among rice genotypes for grain size, milling quality, cooking properties, protein, and the mineral contents of Fe, Zn, Mn, and Cu in unpolished rice varieties. Further, relationship among grain quality traits and mineral contents was determined. The results showed that the visible difference could be found in the mineral contents among rice genotypes studied. The contents of Fe and Zn in traditional genotypes were significantly higher than those of improved cultivars. There was a negative correlation between grain yield and mineral contents. However, Fe, Zn, Mn, and Cu contents appeared to be positively correlated. The relationships between mineral element contents and cooking quality traits viz., kernel length after cooking and kernel linear elongation ratio were positively correlated, indicated the role of micronutrients in cooking quality traits. Both Fe and Cu contents were correlated positively and significantly with head rice recovery. The eigen values of 1st 6 principal components (PC) were > 1.0. The present study suggests that breeding for high minerals will be probably realistic.     

Characterization of biodegradable poly(l-lactide) tube over accelerated degradation

The next-generation bioresorbable polymeric stents are undergoing continual research and development, especially how to control and optimize their degradation behaviors. The aim of this paper is to study the properties of a poly(l -lactide) (PLLA) tube over accelerated degradation in vitro. Spherical nanoindentation was particularly adopted to measure the mechanical properties of PLLA tube; while differential scanning calorimetry and gel permeation chromatography were used for crystallinity and molecular weight measurements. Overall, the material degradation was captured by the local stress-strain response obtained with spherical nanoindentation, and further confirmed with chemical analyses. The results are particularly useful for development of bioresorbable polymeric stents with improved performance.