Particulate matter pollution in opencast coal mining areas: a threat to human health and environment

With the increase in depth of mines, the movement and dispersion of particulate matter (PM) are very difficult to predict due to improper ventilation. Insufficient open pit ventilation remains the principal driver for the lack of dispersion and evacuation from mines and ultimately increases the time and amount of exposure to miners. Studies suggest that there is a direct and dependent relationship between the composition and exposure time to PM in mining operations. Furthermore, this paper helps the reader appreciate the need of carrying out studies to understand the nature of the dispersion of PM inside the mines.     

Analysis of flexoelectric response in nanobeams using nonlocal theory of elasticity

This paper is concerned with the derivation of exact solutions for the static responses of simply supported nonlocal flexoelectric nanobeams. Considering both the direct and the converse flexoelectric effects, and employing the nonlocal theory of elasticity, the governing equations and the associated boundary conditions of the beams are derived to obtain the exact solutions for the displacements, nonlocal stresses and the electric potential in the beams. Both the direct and the converse flexoelectric effects are influenced by the nonlocal parameter. Active beams significantly counteract the applied mechanical load by virtue of the converse flexoelectric effect. The normal and the transverse shear deformations in the beams are affected by the converse flexoelectric effect resulting in the coupling of bending and stretching deformations in the beams even if the beams are homogeneous. Because of the consideration of the nonlocal theory of elasticity, the nonlocal stiffness of the beam appears to be less than the classical stiffness of the beam. The nonlocal elasticity does not influence the stresses of the passive beam while the nonlocal stresses in the active beam due to converse flexoeletric effect are less than the local or classical stresses in the active beam. The benchmark results presented here may be useful for verifying the numerical model and experimental results for nonlocal flexoelectric nanobeams. The present study suggests that the flexoelectric nanobeams may be effectively exploited for developing advanced smart nanosensors and nanoactuators. The research work carried out here also conveys that the nonlocal theory of elasticity must be employed for accurate analysis of flexoelectric solids.     

An overview of caprolactam synthesis

Caprolactam is the precursor of many industrial chemical productions as in nylon industry, plastic industry, paint industry, lysine synthesis and cross-linking for polyurethanes. The production of caprolactam has been focus much from last three decades among the scientific community to fulfill the industrial need under environment precautions. Herein a sequential and explanatory review broadly covering the transformation of a different substrate as cyclohexanone oxime, cyclohexanone, cyclohexanol, cyclohexane, and biorenewable sources into caprolactam is presented. For every substrate, a wide range of catalyst including homogeneous as well as the heterogeneous system has been deeply considered. This study will be helpful for developing alternative industrial route for production of caprolactam.     

Bimodal distribution of filler on viscosity and thermal expansion of glass composites

This paper investigates the bimodal oxide filler system to study the viscous behavior and thermal expansion properties of glass composites. Zinc oxide and cordierite, which are two types of filler, with different average diameters (10 μm and 1 μm, respectively), were considered in a Bi2O3 containing glass with various volume fractions (up to 40 vol%). The experimental results for the composites with the bimodal filler distribution show a reduced viscosity. The viscosity increased from fine particles to coarse particles with an increase in the volume fraction of the composite. Both viscosity and coefficient of thermal expansion (CTE) decreased significantly in the composite with the cordierite filler. The CTE is determined from the volume fraction with respect to particle size and distribution. On the other hand, viscosity is dependent on the particle distribution, particle size, and volume fraction of the composite.     

Hot melt extruded Aprepitant–Soluplus solid dispersion: preformulation considerations,stability and in vitro study

Context: Solubility limitation of BCS class II drugs pose challenges to in vitro release.

Objective: To investigate the miscibility of Aprepitant (APR) and Soluplus^® (SOL) for hot melt extrusion (HME) viability and improved in vitro release of APR.

Methods: Solubility parameters of APR and SOL from group contribution methods were evaluated. Heat–cool–heat differential scanning calorimetry (DSC) scans were assessed for determining the glass forming ability (GFA) and glass stability (GS) of APR. An optimum HME temperature was selected based on melting point depression in physical mixtures. Moisture sorption isotherms were collected using a dynamic vapor sorption (DVS) analyzer at 25?°C. A 1:4 APR:SOL physical mixture was extruded in a co-rotating 12?mm twin screw extruder and in vitro release was assessed in fasted state simulated intestinal fluid (FaSSIF) with 0.25% SLS. Extrudates were analyzed using TGA, DSC, XRD and FTIR.

Results: APR was classified as a class II glass former. APR and SOL had composition dependent miscibility based on Gibb’s free energy of mixing. Extrudate prepared using HME had an amorphous as well as a crystalline phase that showed good stability in accelerated stability conditions. Smaller particle size extrudates exhibited a higher % moisture uptake and in vitro release compared to larger particle size extrudates. Enhanced in vitro release of APR from extrudates was attributed to amorphization of APR, solubilization as well as crystal growth inhibition effect of SOL due to H-bond formation with APR.

Conclusions: A solid dispersion of APR with improved in vitro release was successfully developed using HME technology.     

Piezo-resistive method for tuberculosis detection using microcantilever biosensor

Microcantilever device is utilized in several biosensors for detection of bio-molecule of interest. Biosensors task is to identify presence of targeted molecule and supply result into a measurable signal. Comparing with conventional biological equipments, micro scale biosensors are very fast, reliable and price effective. Microelectromechanical systems (MEMS)/nanoelectromechanical systems are used for designing of such biosensors, which might be utilized in several biological applications. Sensing mechanism of biosensor is varied with the application. This paper is focused on detection of bio-molecule using microcantilever beam. Biosensor has shown here uses piezo-resistive method for detection of targeted bio-molecule. This Bio-MEMS device is designed and simulated using coventorware software. This biosensor wants to identify a presence of T.B. in a very suspected patient. For detection of primary stage of tuberculosis (ESAT-6), specific antibodies need to immobilize on top of microcantilever. Once patient sample (consist of ESAT-6) is placed on functionalized cantilever surface, biochemical reaction happen between tuberculosis antigens ESAT-6 and antibodies. Adsorption of antigens will increase mass working on cantilever and results in bending of microcantilever. This deflection shows the presence of tuberculosis within the patient sample.     

Ink‐jet Printing of Hollow SnO2 Nanospheres for Gas Sensing Applications

Hollow tin‐oxide (SnO₂) nanospheres were synthesized by coating, carbon nanospheres (CNs) as hard templates, with a tin(IV) sol obtained by partial hydrolysis of [Sn(OBu^t)₄] under ambient conditions. Formation of crystalline SnO₂ spheres upon calcination was confirmed by powder X‐ray diffraction data, whereas the hollow interiors of SnO₂ particles were verified by scanning and transmission electron microscopy of both intact and broken spheres. The shell of SnO₂ nanospheres sintered at 700°C consisted of a single layer of nanocrystallites (~6 nm) self‐assembled in a ball‐like superlattice. Tin‐oxide hollow spheres showed an average diameter of 150 nm and could be homogeneously dispersed in water/ethylene glycol (50:50 vol%) mixture to form stable inorganic inks viable for their use in commercial ink‐jet printers demonstrated by printing porous ceramic structures on an interdigitated sensor chip. The integration of large surface and nanoscopic voids in the final structures imparted higher sensitivity to the as‐printed sensors toward both oxidizing (nitrogen dioxide) and reducing gases (methane and ethanol), which validates the enormous potential of printable inorganics in functional applications.     

Lipase‐catalysed acidolysis of mango kernel fat with capric acid to obtain medium‐ and long‐chain triacylglycerols

Mango kernel fat (MKF) was blended with capric acid (1:5 mole ratio) and subjected to acidolysis using 1,3 specific lipase Lipozyme IM (Mucor miehei) for different time intervals (30 min to 24 h). The capric acid content increased gradually up to 43.5 mol% with corresponding decrease in stearic acid content (45.7–17.4 mol%). DSC crystallisation thermograms showed a new exothermic peak at lower temperature, and HPLC profile showed new peaks both indicating the formation of new lower melting triglycerides. A decrease in higher melting triglycerides and gradual increase in new triglycerides was observed. Two prominent newly formed triglycerides were characterised by ESI/MS studies and identified as 2‐oleo‐dicaprin (10, 18′, 10) and stearo‐oleo‐caprin (18, 18′, 10). Solid fat content decreased at all temperatures and samples interesterified for 5 h remained liquid at ambient conditions. The modified MKF can increase the food application from MKF in addition to contributing to health benefits of medium‐ and long‐chain triglycerides.