Threat to the groundwater from municipal landfills sites in Delhi, India

Threat to the groundwater from municipal landfills sites in Delhi, Indi

Analysis of SCF under sales promotional schemes: an application of interpretive structural modelling approach

<p>In the competitive market of today, supply chain flexibility (SCF) plays crucial way to address various supply chain uncertainties. But, in diverse situations, the supply chain needs different types of flexibilities. This paper analyses the flexibility of an automobile supply chain under sales promotional schemes (SPS) to meet the demand uncertainty. Taking the opinion of supply chain experts from automobile original equipment manufacturers (OEM’s), 14 SCF strategies have been identified and then using interpretive structural modelling (ISM) on the conducted survey, their interrelationships are established and a hierarchical model is developed. MICMAC analysis is done to classify the strategies into four categories viz. autonomous, dependent, linkage and independent strategies, which are based on their driving and dependence powers. Sensitivity analysis has been conducted to check the stability of the model. The thorough exposition of the model presents a handful of insights to supply chain managers to know the most important strategies affecting each other. The study helps in bridging the SCF with SPS, a huge gap existing in the literature.</p

Ti/SiO₂ as a Nanosized Solid Catalyst for the Epoxidation of Fatty Acid Methyl Esters and Triglycerides

The chemical method has been employed to prepare a series of titanium-loaded silica (1.7 wt % Ti on SiO₂), followed by calcination in the temperature range of 550–950 °C. Diffuse reflectance solid-state ultraviolet–visible spectroscopy supported the incorporation of TiO₂ on the silica support and existence of titanium in distorted tetrahedral and octahedral environments. The surface morphology and particle size of Ti/SiO₂ were observed by field emission scanning electron microscopic and transmission electron microscopic techniques and later support the formation of 20–100 nm sized Ti/SiO₂ particles. Prepared Ti/SiO₂ has been employed as a solid catalyst for the epoxidation of fatty acid methyl esters, derived from used cotton seed oil, under two different reaction conditions, viz., (i) H₂O₂ and formic acid and (ii) H₂O₂, acetonitrile, and butyronitrile in the presence of ultraviolet radiation. To demonstrate the versatility of the prepared Ti/SiO₂ catalyst, it was also successfully employed for the epoxidation of a variety of substrates, viz., methyl oleate, used cotton seed oil, and fatty acid methyl esters obtained from soybean, Karanja, and Jatropha oils. Under optimized reaction conditions in both methods, the prepared Ti/SiO₂ catalyst afforded a high epoxide yield (100%) even at room temperature (35 °C). The catalyst was amenable to recovery and recycling for at least five consecutive reaction cycles with the partial loss of activity after every successive run. Finally, the synthesized epoxidized fatty acid methyl esters have been tested as lubricity improver additives for diesel fuel

Elastoplastic Stability and Failure Analysis of FGM Plate with Temperature Dependent Material Properties under Thermomechanical Loading

<div><p>Abstract The present paper explores the stability and failure response of elastoplastic Ni/Al2O3 functionally graded plate under thermomechanical load using non-linear finite element formulation based on first-order shear deformation theory and von-Karman’s nonlinear kinematics. The temperature dependent thermoelastic material properties of FGM plate are varied in the thickness direction by controlling the volume fraction of the constituent materials (i.e., ceramic and metal) with a power law, and Mori-Tanaka homogenization scheme is applied to evaluate the properties at a particular thickness coordinate of FGM plate. The elastoplastic behavior of FGM plate is assumed to follow J2-plasticity with isotropic hardening, wherein the ceramic phase is considered to be elastic whereas the metal is assumed to be elastic-plastic in accordance with the Tamura-Tomota-Ozawa model. Numerical studies are conducted to examine the effects of material and geometrical parameters, viz. material in-homogeneity, slenderness and aspect ratios on the elastoplastic bucking and postbuckling behavior and the failure response of FGM plate. It is revealed that material gradation affects the stability and failure behavior of FGM plate considerably. Furthermore, it is also concluded that FGM plate with elastic material properties exhibits only stable equilibrium path, whereas the elastoplastic FGM plate shows destabilizing response after the ultimate failure point.</p></div

Transesterification of Low-Quality Triglycerides over a Zn/CaO Heterogeneous Catalyst: Kinetics and Reusability Studies

Zinc-doped (0.25–7 wt %) calcium oxide (Zn/CaO) has been prepared in nanocrystalline form by a simple wet chemical method followed by calcination up to 950 °C. The structural analysis has been investigated by powder X-ray diffraction (XRD), whereas the surface morphology and average particle size of Zn/CaO were determined by scanning electron and transmission electron microscopic studies, respectively. The catalytic activity of the prepared Zn/CaO toward the transesterification of cotton seed oil with methanol was found to be a function of its calcination temperature, crystallite size, and basic strength. A pseudo-first-order kinetic model was applied to evaluate the kinetic parameters for the transesterification of waste cotton seed oil with methanol, and a first-order rate constant (<i>k</i>) and activation energy (<i>E</i>_a) were found to be 0.10 min^–1 and 43 kJ mol^–1, respectively. The catalyst, Zn/CaO, was amenable to recovery and recycling for at least five consecutive reaction cycles. The Koros–Nowak criterion test has been employed to demonstrate that measured catalytic activity was independent of the influence of transport phenomenon. Further, Zn/CaO was also found as an efficient catalyst for the complete transesterification of a variety of triglycerides (having up to 8.4 wt % free fatty acids), such as virgin cotton seed oil, soybean oil, waste cotton seed oil, castor oil, karanja oil, jatropha oil, and mutton fat. Thus, the present work demonstrates the application of high free fatty acid containing waste or non-edible oils as feedstock, without any pre-treatment, for biodiesel production

Adsorption Equilibrium, Kinetics, and Thermodynamic Studies of Fluoride Adsorbed by Tetrametallic Oxide Adsorbent

This study investigated the performance of fluoride adsorption onto a specific tetrametallic oxide adsorbent Fe–Al–Ce-Ni (FACN) and the effect of temperature on adsorption performance. The adsorption performance was determined by adsorption equilibrium, kinetics, and thermodynamic parameters. The adsorption, kinetic, and thermodynamic parameters were compared alternatively. The fluoride adsorption capacity was obtained from four different adsorption isotherm models, namely, Langmuir, Freundlich, Temkin, and Dubinin–Radushkevich (D–R), and Freundlich was found to best fit model. Fluoride removal rate using adsorption (0.27 min^–1) was obtained faster than reactive adsorption (0.04 min^–1). Several thermodynamic parameters such as enthalpy, Gibbs free energy, entropy (Δ<i>S</i> > 0), and adsorption activation energy were calculated which demonstrated the feasibility and spontaneity (Δ<i>G</i> < 0) and exothermic nature of (Δ<i>H</i> < 0) the fluoride adsorption process. The adsorption process was controlled by a physical mechanism, and the maximum adsorption capacity was found to be 250 mg/g. To our knowledge, this is the first report on the synthesis of tetrametallic oxide adsorbent for fluoride adsorption, and the feasibility of the adsorption process was ratified by three van’t Hoff plots

Designed Isomorphism of Nifedipine: A Joint Experimental and Molecular Simulation Study with Screened Solvents and Antisolvents

Controlling the shape of crystals is of great practical relevance in pharmaceutical manufacturing. In the present study, an attempt was made to correlate experimental and simulated crystal habits of nifedipine (Nif). Modified habits with isodiametric morphology were observed in the following solvent and solvent/antisolvent pairs; chloroform/hexane, chloroform/isopropyl alcohol (IPA), dichloromethane (DCM), DCM/IPA, and ethanol/hexane. Presence of any solvates or polymorphs was ruled out by using differential scanning calorimetry, thermogravimetric analysis, Fourier transform infrared spectroscopy, and powder X-ray diffraction. A solvent effect was introduced by surface docking to bridge the gap between experimental and simulated habits as they deviated from vacuum morphology. Molecular dynamics was performed, and modified attachment energy was calculated to obtain the final morphology. The achieved predictions were found to be in good agreement with the experimental habits (statistically significant with <i>p</i> < 0.05). Similarly, significant enhancement (1.5–2.5 times) in solubility and dissolution behavior of the modified habits was observed compared with the untreated drug. Nif with chloroform/IPA combination showed isodiametric habit with better solubility and dissolution rate, which was attributed to their high surface/volume ratio. Good correlation was observed between polarity of crystallization solvents and nature of functional moiety of a specific facet. The methodology used here could prove to be a powerful tool for selection of habit modifying solvents since prediction of morphologies was demonstrated successfully

Influence of Imidazolium Ionic Liquids on the Interactions of Human Hemoglobin with DyCl₃, ErCl₃, and YbCl₃ in Aqueous Citric Acid at <i>T</i> = (298.15, 303.15, and 308.15) K and 0.1 MPa

Density, sound velocity, viscosity, surface tension, and molar conductivity for DyCl₃·6H₂O, ErCl₃·6H₂O, and YbCl₃·6H₂O from (0.002 to 0.012) mol·kg^–1 in aqueous solutions of (a) citric acid (0.005 mol·kg^–1) (b) citric acid + human hemoglobin (1 g·kg^–1) and (c) citric acid + human hemoglobin +1-alkyl-3-methylimidazolium chloride (0.001 mol·kg^–1) ([RMIMCl], R = ethyl, butyl, and hexyl) at <i>T</i> = (298.15, 303.15, and 308.15) K and 0.1 MPa are reported. Densities were used to calculate the apparent molar volumes. The viscosity data are analyzed and interpreted using the extended Jones–Dole equation for lanthanide chloride to calculate viscosity <i>A</i>- and <i>B</i>-coefficient values. The varying trends of the aforesaid physicochemical parameters have been interpreted in terms of the solute–solute and solute–solvent interactions. An attempt has been made to investigate the influence of ionic liquid alkyl chain length on the interacting activities of lanthanide chloride with citric acid and the critical role being played by human hemoglobin in decoding the dominance of hydrophilic–hydrophobic interactions. 1-Ethyl-3-methylimidazolium chloride induced greater conformational changes in the human hemoglobin than 1-butyl-3-methylimidazolium chloride and 1-hexyl-3-methylimidazolium chloride due to differences in alkyl chain length with different interacting capabilities

Influence of Urea on Shifting Hydrophilic to Hydrophobic Interactions of Pr(NO₃)₃, Sm(NO₃)₃, and Gd(NO₃)₃ with BSA in Aqueous Citric Acid: A Volumetric, Viscometric, and Surface Tension Study

Density, surface tension, and viscosity for hexahydrate nitrate salts of praseodymium, samarium, and gadolinium from (0.023 to 0.150) mol·kg^–1 in aqueous solutions of: (a) citric acid (1.11 mol·kg^–1), (b) citric acid + urea, (c) citric acid + bovine serum albumin, and (d) citric acid + urea + bovine serum albumin at 298.15 K and atmospheric pressure are reported. By using densities and viscosities, the apparent molar volumes, limiting apparent molar volumes, apparent molar transfer volumes, and viscosity <i>B</i>-coefficients have been calculated. The varying trends of aforesaid physicochemical parameters have been interpreted in light of the solute–solvent and solute–solute interactions. An attempt has thus been made to investigate the influence of urea on the interacting activities of lanthanide nitrate with citric acid and the critical role being played by bovine serum albumin in decoding the dominance of hydrophilic–hydrophobic interactions