Green route for the utilization of chrome shavings (chromium-containing solid waste) in tanning industry

Chromium-containing wastes from various industrial sectors are under critical review. Leather processing is one such industrial activity that generates chromium-bearing wastes in different forms. One of them is chrome shavings, and this contributes to an extent of 10% of the quantum of raw skins/hides processed, amounting to 0.8 million ton globally. In this study, the high protein content of chrome shavings has been utilized for reduction of chromium(VI) in the preparation of chrome tanning agent. This approach has been exploited for the development of two products: one with chrome shavings alone as reducing agent and the other with equal proportion of chrome shavings and molasses. The developed products exhibit more masking due to the formation of intermediate organic oligopeptides. This has been corroborated through the spectral, hydrolysis, and species-wise distribution studies. The formation of these organic masking agents helps in chrome tanning by shifting the precipitation point of chromium to relatively higher pH levels. Hence, the developed products find use as chrome tanning agents for leather processing, thus providing a means for better utilization of chrome shaving wastes.     

Micro-kinetic modeling of NH3 decomposition on Ni and its application to solid oxide fuel cells

This paper presents a detailed surface reaction mechanism for the decomposition of NH₃ to H₂ and N₂ on a Ni surface. The mechanism is validated for temperatures ranging from 700 to 1500 K and pressures from 5.3 Pa to 100 kPa. The activation energies for various elementary steps are calculated using the unity bond index-quadratic exponential potential (UBI-QEP) method. Sensitivity analysis is carried out to study the influence of various kinetic parameters on reaction rates. The NH₃ decomposition mechanism is used to simulate SOFC button cell operating on NH₃ fuel.     

Nonaligned carbon nanotubes anchored on porous alumina: formation, process modeling, gas-phase analysis, and field-emission properties

We have developed a chemical vapor deposition (CVD) process for the catalytic growth of carbon nanotubes (CNTs), anchored in a comose-type structure on top of porous alumina substrates. The mass-flow conditions of precursor and carrier gases and temperature distributions in the CVD reactor were studied by transient computational fluid dynamic simulation. Molecular-beam quadrupole mass spectroscopy (MB-QMS) has been used to analyze the gas phase during ferrocene CVD under reaction conditions (1073 K) in the boundary layer near the substrate. Field-emission (FE) properties of the nonaligned CNTs were measured for various coverages and pore diameters of the alumina. Samples with more dense CNT populations provided emitter-number densities up to 48,000 cm(-2) at an electric field of 6 V microm(-1). Samples with fewer but well-anchored CNTs in 22-nm pores yielded the highest current densities. Up to 83 mA cm(-2) at 7 V microm(-1) in dc mode and more than 200 mA cm(-2) at 11 V microm(-1) in pulsed diode operation have been achieved from a cathode size of 24 mm2.     

Optimal discrete higher‐order sliding mode control of uncertain LTI systems with partial state information

The concept of discrete higher‐order sliding mode has received increased attention in the recent literature. This paper presents an optimal discrete higher‐order sliding mode control for an uncertain discrete LTI system using partial state information, which has been missing in literature. A new technique is proposed to design an optimal time‐varying higher‐order sliding surface and control input through the minimization of a quadratic performance index. Moreover, disturbance estimation technique is utilized to modify the control algorithm to reduce the width of the discrete higher‐order sliding mode band. The proposed algorithm is experimentally validated on a rectilinear plant. Copyright © 2017 John Wiley & Sons, Ltd.     

Combined extracts of <Emphasis Type="Italic">Garcinia mangostana</Emphasis> fruit rind and <Emphasis Type="Italic">Cinnamomum tamala</Emphasis> leaf supplementation enhances muscle strength and endurance in resistance trained males

Background

A proprietary composition GMCT contains extracts of two popular Asian herbs viz., Garcinia mangostana (GM) fruit rind and Cinnamomum tamala (CT) leaf. We systematically evaluated physical performance and muscle strength enhancing ability of GMCT in a preclinical mouse model followed by a 42-days double-blind placebo controlled human trial in resistance trained adult males.

Methods

Four groups of Swiss albino mice (20–30 g body weight) (n?=?6) were fed a standard laboratory diet and given Carboxymethylcellulose sodium (CMC), 150 mg/kg GMCT (GMCT-150), 300 mg/kg GMCT (GMCT-300) or 50 mg/kg Oxymetholone (OXY) via oral gavage for 21 days. On day 22, the animals’ physical performance and muscle strength were assessed in a forced swimming test (FST) and forelimb grip strength experiment, respectively.In the human trial, thirty-eight resistance-trained young adults (mean age 26.32?±?4.39 years, body weight 67.79?±?12.84 kg, BMI 22.92?±?3.54 kg/m²) completed the trial. The participants received either GMCT (n?=?19; 800 mg daily) or matched placebo (n?=?19) for 42 days. As primary variables, 1-RM bench press, 1-RM leg press, and leg extension repetitions were measured at baseline and on days 14, 28 and 42 of the intervention. Anthropometric parameters and serum markers such as free testosterone, insulin-like growth factor 1 (IGF-1), insulin and lactate were also measured before and after the intervention.

Results

GMCT-300 mice showed significant improvement in swimming time (GMCT: 395.3?±?81.70 s vs. CMC: 271.6?±?56.86 s; p?=?0.0166), distance (GMCT: 341.22?±?65.88 m vs. CMC: 260.84?±?49.15 m; p?=?0.0461) and grip strength (GMCT: 43.92?±?6.97 N vs. CMC: 35.0?±?6.92 N; p?=?0.0490), compared with the CMC group.At the end of the 42-day human trial, the per protocol analyses reveal that mean changes from baseline 1-RM bench press (GMCT: 23.47?±?10.07 kg vs. PL: 3.42?±?2.06 kg; p?<?0.0001), leg press (GMCT: 29.32?±?16.17 kg vs. PL: 5.21?±?1.72 kg; p?<?0.0001), number of leg extension repetitions (GMCT: 6.58?±?2.57 vs. PL: 2.05?±?1.22; p?<?0.0001) in GMCT group were significantly improved, compared with placebo. Intergroup difference analyses show that the changes from baseline left arm (GMCT: 1.09?±?0.36 cm vs. PL: 0.68?±?0.42 cm; p?=?0.0023), right arm (GMCT: 1.50?±?0.44 cm vs. PL: 1.11?±?0.43 cm; p?=?0.0088) circumference and lean mass (GMCT: 2.29?±?2.09 kg vs. PL: 0.52?±?2.58 kg; p?=?0.0404) in GMCT group were also significantly improved, compared with placebo. In comparison to placebo, GMCT supplementation did not improve free testosterone, IGF-1, insulin or lactate levels. Parameters of clinical biochemistry, hematology, urine and vital signs of the participants were within the normal range.

Conclusion

GMCT supplementation is effective in increasing muscle strength, muscle size and, total lean mass, as well as endurance performance.Trial Registration.Clinical Trial Registry of India (CTRI/2015/01/005374), Registered on Jan 07, 2015; CTRI Website URL - http://ctri.nic.in

     

Comparative study on the antioxidant activity of methanolic and aqueous extracts from the fruiting bodies of an edible mushroom <Emphasis Type="Italic">Pleurotus djamor</Emphasis>

In vitro antioxidant activities, total phenolic, and flavonoid contents of Pleurotus djamor extracts were analyzed based on radical scavenging activities of methanol and aqueous extracts using 1,1-diphenyl-2-picryl-hydrazyl (DPPH), N,N-dimethyl-p-phenylenediamine (DMPD), total Fe³⁺ reducing power, CUPRAC, phosphomolybdenum, metal chelating activity, and lipid peroxidation inhibition assays. Both extract types showed efficient radical scavenging activities against DPPH and DMPD radicals, ferric (Fe³⁺) and cupric (Cu²⁺) ion reducing powers, metal chelating activities, and lipid peroxidation inhibition. Total phenolic contents of methanol and aqueous extracts were 2.79 and 5.95 mg of GAE/g, respectively. Flavonoid contents of methanol and aqueous extracts were 6.35 and 5.75 mg of CAE/g, respectively. Consumption of the mushroom P. djamor can be beneficial due to antioxidant properties.     

Modeling diffusion limitation in solid-oxide fuel cells

Effect of surface diffusion on the performance of solid-oxide fuel cell is investigated. A methodical approach for the evaluation of surface diffusion coefficients of various adsorbed species based on bond-order conservation Morse potential (BOC-MP) method is presented. The surface diffusion fluxes are used for the evaluation of temporal changes in surface coverages. Our analysis shows that surface diffusion does not lead to the concentration losses in solid oxide fuel cells. Further analysis is carried out and results are presented to substantiate the significance of interface diffusion on the behavior of voltage at limiting current.     

Butyl rubber–Ba0.7Sr0.3TiO3 composites for flexible microwave electronic applications

Butyl rubber–Ba_0.7Sr_0.3TiO₃ composites (BR–BST) were prepared by sigma mixing followed by hot pressing. The stress–strain studies show the good flexibility of the composite. The dielectric properties of the composites were investigated at both radio and microwave frequencies. The relative permittivity (ε_r) and loss tangent (tan δ) improved with filler loading at both the frequencies. The relative permittivity and loss tangent of the BR–BST composites at a maximum filler loading of 0.39 volume fraction (v_f) are 13.1 and 0.009 respectively at 5 GHz measured by Split Post Dielectric Resonator (SPDR). The effective relative permittivity of the BR–BST composites is compared with theoretical models. The variation of ε_r with temperature was also investigated in the range 22–80 °C at 1 MHz. The microwave dielectric properties of the composites are also studied after repeated bending. The coefficient of thermal expansion (CTE) of the butyl rubber–BST composites decreased with the addition of the BST ceramic.     

Effects of wall-heating on the linear instability characteristics of pressure-driven two-layer channel flow

The linear stability analysis of a pressure-driven two-layer channel flow of two immiscible, Newtonian and incompressible fluids is considered. The walls of the channel are maintained at different constant temperatures and Nahme's law is applied to model the temperature dependence of the fluid viscosity. A modified Orr–Sommerfeld equation for the disturbance streamfunction coupled to a linearized energy equation is derived and solved using a spectral collocation method. Our results indicate that increasing the dimensionless top wall temperature has a non-monotonic effect on the linear stability characteristics. We also found that increasing the thermal conductivity and density ratios stabilise the flow for the set of parameter values considered; the viscosity ratio has a non-monotonic effect on the maximal growth rate. An energy ‘budget’ analysis shows that the most dangerous mode is of ‘interfacial’ type.     

The nutritional and antinutritional attributes of sword bean [Canavalia gladiata (Jacq.) DC.]: an under-utilized tribal pulse from south India

Six accessions [three with maroon‐coloured seed coat and three with white‐coloured seed coat) of sword bean (Canavalia gladiata (Jacq.) DC.], were collected from six different locations in south India. They were analysed for their proximate and mineral composition, amino acid profiles of total seed proteins, in vitro protein digestibility (IVPD) and certain antinutritional factors. The essential amino acid profile of total seed proteins compared favourably with FAO/WHO requirements, except that there were deficiencies of sulphur containing amino acids in all the six accessions and also the leucine, lysine and tryptophan contents were low in maroon‐coloured seed coat accessions. The IVPD of the accessions ranged from 63.39 to 76.92%. Antinutritional substances like total free phenolics, tannins, l ‐DOPA (3,4‐dihydroxyphenylalanine), trypsin inhibitor activity and phytohaemagglutinating activity were also investigated. The antinutritional factors that were detected were thought to have little nutritional significance if the beans are properly processed.