Stability of betacyanin from red pitahaya (Hylocereus polyrhizus) and its potential application as a natural colourant in milk

The effects of temperature (30, 50, 85 and 100 °C) treatment and 10 weeks of refrigerated storage (4 °C) on the betacyanin content and colour stability of betacyanins from red pitahaya (Hylocereus polyrhizus) were investigated and compared to red beet (Beta vulgaris; E‐162) which was used as a control. Temperature treatment at 50 and 85 °C caused a greater reduction in betacyanin content (BC) in E‐162 compared to red pitahaya by inducing changes in betacyanin profile. The 10 weeks of refrigerated storage at 4 °C induced colour changes in betacyanins from red pitahaya and E‐162. In milk, betacyanins from red pitahaya presented a lower loss of BC and total colour changes (ΔE*) compared to E‐162. The microbial onset in milk containing betacyanins from red pitahaya and E‐162 was delayed up to day 5 of refrigerated storage at 4 °C compared to day 3 in plain milk. Milk containing betacyanins from red pitahaya showed better colour acceptability (3.89 ± 1.89) compared to E‐162 (6.10 ± 1.71). Hence, betacyanins from red pitahaya may be a potential natural functional colourant to simulate strawberry colour in milk.     

Processing of Mica for Extraction of Alumina and Potash Values

Mica sample containing 34% alumina and 9% potash has been investigated as a potential dual source of alumina and potash. It was found that planetary milling had a strong effect on structure breakdown as well as on the release of alumina and potash values. Both alumina and potash were extracted from mica using mechanical milling followed by hydrochloric acid leaching and precipitation process. The optimal conditions derived from statistical design yielded 72% alumina and 75% potash values in the form of γ-alumina and sylvinite. The analysis of the final precipitate was carried out by different characterization techniques such as XRD, SEM–EDS, XRF, BET surface area analysis.

     

Machining and Characterization of Multidirectional Hybrid Silica Glass Fiber Reinforced Composite Laminates Using Abrasive Jet Machining

Silicon - Machining of multidirectional Hybrid Fiber Reinforced Composite (HFRC) is a challenging task because of defects like matrix cracking, fiber pullouts, delamination, burr formation, and...     

pH‐responsive fibers based on acrylonitrile acrylic acid block copolymers: Effect of spinning conditions and postspinning operations on response and mechanical properties

pH sensitive poly(acrylonitrile‐co‐acrylic acid) having ～50 mol % acrylic acid with block type structure (AA50B) was synthesized by controlled dosing method of free radical polymerization. The polymer was converted into fibers by wet solution spinning technique in DMF‐water system. The resulting block type copolymer could generate a domain type morphology with segregated domains of acrylonitrile and acrylic acid on heat‐setting. The drawing ratio and heat‐setting temperature had a significant effect on the formation of these domains and their stability. The domain formation was more pronounced when the fibers could be drawn to higher draw ratios during coagulation or heat‐set at higher temperature. The stability of the fibers, which is influenced by domain formation, was lowest (at few cycles of transitions) when the fibers were heat‐set at 100°C, while it is improved significantly to more than 50 cycles as the heat‐setting temperature was increased to 150°C. The coagulation conditions, drawing and the heat‐setting also greatly influenced the mechanical properties, transition behavior, and retractive stresses of the responsive fibers. The tenacity improved by 6.6 times in swollen state and 1.4 times in deswollen state, while the retractive stresses during deswelling were significantly increased to about 4.7 times. However, the increased heat‐setting temperature was also found to have a negative effect on the equilibrium swelling values as well as the response rate. The effect of heat‐setting on chemical structure of the copolymer was also investigated. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

Effect of material parameter on mixed convective fully developed micropolar fluid flow in a vertical channel

In this study, the effect of material parameter on the mixed convective fully developed micropolar fluid flow in a vertical channel has been analyzed. By considering appropriate boundary and interface conditions, the coupled nonlinear equations are solved analytically. The analytical results are plotted for various important parameters. It is found that an increase in the material parameter enhances the microrotation velocity and decreases the fluid velocity, and the results are shown graphically.     

Electrospun self‐assembled nanofiber yarns

A technique for making self‐assembled electrospun (E‐spun) nanofiber yarns from poly(acrylonitrile) in a single step is described. The process involved formation of the nanofiber yarn directly within the electrospinning zone and its removal before it can reach the counter‐electrode. The yarn is presumably formed due to splitting of the main jet into numerous nanojets and their reassembly into a single entity midway between the two electrodes. The process was found to occur at a particular field strength, which varied considerably with the concentration of the polymer dope. The gross morphology of yarns and the alignment of nanofibers in the yarn were evaluated by scanning electron microscopy (SEM). The rationale behind the formation of the yarn like structure has been explained. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

Renewable energy sources from Michelia champaca and Garcinia indica seed oils: A rich source of oil

Michelia champaca and Garcinia indica seeds yielded 45.0% and 45.5% of oil. The fatty acid profiles of both the seed oils were examined. The saponification value (SV), iodine value (IV) and cetane number (CN) of fatty acid methyl esters of both the seed oils were empirically determined. The saponification value (SV) and iodine value (IV) are in good agreement with the experimentally observed values. The fatty acid compositions, iodine value and cetane number were used to predict the quality of fatty acid methyl esters of oil for use as biodiesel. Thus, the fatty acid methyl esters of seed oils of M. champaca and G. indica were found to be the most suitable biodiesel and they meet the major specification of biodiesel standards. The selected plants M. champaca and G. indica have great potential for biodiesel. M. champaca and G. indica seed oils were found to contain keto fatty acids along with the other normal fatty acids, respectively. These fatty acids have been detected and characterized by UV, FTIR, ¹H NMR, ¹³C NMR, MS, GC techniques and chemical transformations.     

Reversible Covalent Inhibition of eEF‐2K by Carbonitriles

eEF‐2K is a potential target for treating cancer. However, potent specific inhibitors for this enzyme are lacking. Previously, we identified 2,6‐diamino‐4‐(2‐fluorophenyl)‐4H‐thiopyran‐3,5‐dicarbonitrile (DFTD) as an inhibitor of eEF‐2K. Here we describe its mechanism of action against eEF‐2K, on the basis of kinetic, mutational, and docking studies, and use chemoinformatic approaches to identify a similar class of carbonitrile‐containing compounds that exhibit the same mechanism of action. We show that DFTD behaves as a reversible covalent inhibitor of eEF‐2K with a two‐step mechanism of inhibition: a fast initial binding step, followed by a slower reversible inactivation step. Molecular docking suggests that a nitrile group of DFTD binds within 4.5 Å of the active site Cys146 to form a reversible thioimidate adduct. Because Cys146 is not conserved amongst other related kinases, targeting this residue holds promise for the development of selective covalent inhibitors of eEF‐2K.     

Computationally-efficient and scalable parallel implementation of chemistry in simulations of turbulent combustion

Large scale combined Large-Eddy Simulation (LES)/Probability Density Function (PDF) parallel computations of reactive flows with detailed chemistry involving large numbers of species and reactions are computationally expensive. Among the various techniques used to reduce the computational cost of representing chemistry, the three approaches in widest use are: (1) mechanism reduction, (2) dimension reduction, and (3) tabulation. In addition to these approaches, in large scale parallel LES/PDF computations, we need strategies to distribute the chemistry workload among the participating cores to reduce the overall wall clock time of the computations. Here we present computationally-efficient strategies for implementing chemistry in parallel LES/PDF computations using in situ adaptive tabulation (ISAT) and x2f_mpi – a Fortran library for parallel vector-valued function evaluation (used with ISAT in this context). To test the strategies, we perform LES/PDF computations of the Sandia Flame D with chemistry represented using (a) a 16-species augmented reduced mechanism; and (b) a 38-species C₁–C₄ skeletal mechanism. We present three parallel strategies for redistributing the chemistry workload, namely (a) PLP, purely local processing; (b) URAN, the uniform random distribution of chemistry computations among all cores following an early stage of PLP; and (c) P-URAN, a Partitioned URAN strategy that redistributes the workload only among partitions or subsets of the cores. We show that among these three strategies, the P-URAN strategy (i) yields the lowest wall clock time, which is within a factor of 1.5 and 1.7 of estimates for the lowest theoretically achievable wall clock time for the 16-species and 38-species mechanisms, respectively; and (ii) for reaction, achieves a relative weak scaling efficiency of about 85% when scaling from 2304 to 9216 cores and a relative strong scaling efficiency of over 60% when scaling from 1152 to 6144 cores.