Sulphur mustard vapor breakthrough behaviour on reactive carbon systems

Breakthrough behaviour of sulphur mustard, the deadliest of persistent chemical warfare agents, on carbon systems such as NaOH/CrO(3)/C, NaOH/CrO(3)/EDA/C and RuCl(3)/C has been studied and the data were compared with that of active carbon. Effects of bed lengths of carbons on breakthrough time have also been correlated. Thereafter, the effects of flow rate of air-sulphur mustard mixture, concentration and temperature on the kinetic parameters such as rate constant (k(v)) and kinetic saturation capacity (W(e)) were analyzed and interpreted by means of modified Wheeler equation. Rate constant was found to be increasing while W(e) was found to be invariable with the increase in air flow rate. Both k(v) and W(e) decreased with the increase of temperature, however, no significant effect on W(e) and k(v) was observed due to concentration change (0.3-0.6 mg/l). The values of kinetic saturation capacity were used to predict the service lives/breakthrough times of carbon beds (when used in filtration systems).     

Breakthrough behavior of diethyl sulphide vapor on active carbon systems

Breakthrough behavior of diethyl sulphide vapors on carbon systems such as active carbon, NaOH/CrO3/C, NaOH/CrO3/EDA/C and RuCl3/C has been studied by using modified Wheeler equation and the same was used to calculate the pseudo-first-order rate constant (kv) and kinetic saturation of capacity (W(e)) values. Effects of various parameters such as bed height, air flow rate, concentration and temperature on the above parameters have also been studied. Rate constant was found to be increasing with air flow rate, while W(e) was found to be invariable. Both kv and W(e) decreased with the increase in temperature, however, no significant effect on W(e) and kv was observed due to concentration change. The values of kinetic saturation capacity were used to predict the service lives/breakthrough times of carbon beds (when used in filtration systems).     

Development of FeSiB/CoSiB Bilayered Melt-spun Ribbon by?Melt-spinning Technique

The investigation addresses the bilayer melt-spun ribbons in which the positively magnetostrictive layer Fe_77.5Si_7.5B₁₅ is toward the free surface, while the negatively magnetostrictive layer of Co_72.5Si_12.5B₁₅ forms the one in contact with the quench wheel. Scanning electron microscopy (SEM) elemental scan showed drastic changes in concentration profiles of Co, Fe and Si across the bilayer, indicating the efficacy of rapid quenching by melt spinning. Crystallization onsets, saturation magnetization and dilatation studies of the single-layered alloys distinctly reflected the properties of the bilayered ribbons. The thermal variation of coercivity below crystallization onset in the case of a bilayer revealed a softening mechanism due to reduction of stresses. Ribbon deflection studies showed interesting results.     

Lateral straggling and its influence on lateral diffusion in implantation with a focused ion beam

Parallel stripes of nanostructures on an n-type Si substrate have been fabricated by implanting 30 keV Ga⁺ ions from a focused ion beam (FIB) source at three different fluences: 1 × 10¹⁵, 2 × 10¹⁵ and 5 × 10¹⁵ ions/cm². Two sets of implantation were carried out. In one case, during implantation the substrate was held at room temperature and in the other case at 400 °C. Photoemission electron microscopy (PEEM) measurements were carried out on these samples. The implanted parallel stripes, each with a nominal dimension of 4000 × 100 nm², appear as bright regions in the PEEM image. Line scans of the intensities from PEEM images were recorded along and across these stripes. Intensity profile at the edges of a line scan is broader for the implantation carried out at 400 °C compared to room temperature. From the analysis of this intensity profile lateral diffusion coefficient of Ga in silicon was estimated assuming that the PEEM intensity is proportional to Ga concentration. The diffusion coefficient at 400 °C has been estimated to be ∼10⁻¹⁵ m²/s. No significant dependence of diffusion coefficient on ion fluence was observed in the fluence range investigated here. Radiation enhanced diffusion has been discussed in the light of the associated defect distribution due to lateral straggling of the implanted ions.     

Significance of porous structure on degradatin of 2,2' dichloro diethyl sulphide and 2 chloroethyl ethyl sulphide on the surface of vanadium oxide nanostructure

Degradation of the king of chemical warfare agent, 2,2' dichloro diethyl sulphide (HD), and its simulant 2 chloroethyl ethyl sulphide (CEES) were investigated on the surface of porous vanadium oxide nanotubes at room temperature (30 ± 2°C). Reaction kinetics was monitored by GC-FID technique and the reaction products were characterized by GC-MS. Data indicates that HD degraded faster relative to CEES inside the solid decontaminant compared to the reported liquid phase degradation of CEES and HD. Data explores the role of hydrolysis, elimination and oxidation reactions in the detoxification of HD and CEES and the first order rate constant and t(1/2) were calculated to be 0.026 h(-1), 26.6h for CEES and 0.052 h(-1), 13.24h for HD. In this report faster degradation of HD compared to CEES was explained on the basis of porous structure.     

Effect of calcinations temperature of CuO nanoparticle on the kinetics of decontamination and decontamination products of sulphur mustard

Present study investigates the potential of CuO nanoparticles calcined at different temperature for the decontamination of persistent chemical warfare agent sulphur mustard (HD) at room temperature (30 ± 2 °C). Nanoparticles were synthesized by precipitation method and characterized by using SEM, EDAX, XRD, and Raman Spectroscopy. Synthesized nanoparticles were tested as destructive adsorbents for the degradation of HD. Reactions were monitored by GC-FID technique and the reaction products characterized by GC-MS. It was observed that the rate of degradation of HD decreases with the increase in calcination temperature and there is a change in the percentage of product of HD degradation. GC-MS data indicated that the elimination product increases with increase in calcination temperature whereas the hydrolysis product decreases.     

Novel moisture-cured hyperbranched urethane alkyd resin for coating application

A hyperbranched polyol (HBP) was synthesized using dipentaerythritol as a core material and 2,2-bis(methylol) propionic acid as a chain extender. This was reacted with varying concentrations of soya fatty acid to make hyperbranched alkyd (HBA) resins. The HBA resins containing unreacted hydroxyl groups were reacted with isophorone diisocyanate at NCO/OH ratio of 1.6:1 to make high solid hyperbranched urethane alkyd (HBUA) resins. The excess NCO content in the HBUA resins was used to cure with atmospheric moisture, and thus moisture-cured HBUA coatings were formed. The resins were characterized by FTIR, and ¹³C NMR spectroscopic analysis. A series of such resins were made using different fatty acid/isocyanate ratios with respect to the hydroxyl groups present in the HBP. The effect of compositions on the mechanical and weathering properties of the cured resins was investigated. It was observed that there was an optimum fatty acid–isocyanate ratio in terms of the requirements of solvent, mechanical and weathering properties of the resin. The requirement of solvents for formulating HBUA coatings is much lower compared to linear alkyd-based coatings. The present study reveals that the moisture-cured HBUA resins can be used as a binder material in the field of low-pollution weather-resistance coatings.     

Microhydrogel-Mediated Synthesis of Sintered Hydroxyapatite Granules

Synthesis of macroporous hydroxyapatite (HA) granules with a controlled microarchitecture has been demonstrated by following a polymer microhydrogel mediated synthesis process coupled with sintering. The process is basically based on in situ nucleation and growth of HA nanoparticles in polymer (polyvinyl alcohol) microhydrogels. A systematic variation of polymer concentration has manifested a controlled evolution of a hierarchical macroporous granular structure after sintering.     

Metal Organic Framework-MXene Nanoarchitecture for Fast Responsive and Ultra-Stable Electro-Ionic Artificial Muscles

Electro-ionic soft actuators, capable of continuous deformations replacing non-compliant rigid mechanical components, attract increasing interest in the field of next-generation metaverse interfaces and soft robotics. Here, a novel MXene (Ti₃C₂T_x) electrode anchoring manganese-based 1,3,5-benzenetricarboxylate metal-organic framework (MnBTC) for ultrastable electro-ionic artificial muscles is reported. By a facile supramolecular self-assembly, the Ti₃C₂T_x-MnBTC hybrid nanoarchitecture forms coordinate bond, hydrogen bond, and hydrophilic interaction with the conducting polymer of poly(3,4-ethylenedioxythiophene) polystyrene sulfonate (PEDOT:PSS), resulting in a mechanically flexible and electro-ionically active electrode. The superior electrical and electrochemical performances of the electrode stem from the synergistic effects between intrinsically hierarchical nanoarchitecture of MnBTC and rapid electron transport behavior of Mxene, leading to fast diffusion and accommodation of ions in the ion-exchangeable membrane. The developed artificial muscle based on Ti₃C₂T_x-MnBTC is found to exhibit high bending displacement (12.5 mm) and ultrafast response time (0.77 s) under a low driving voltage (0.5 V), along with wide frequency response (0.1–10 Hz) and exceptional stability (98% retention at 43,200 s) without any distortion of actuation performance. Furthermore, the designed electro-active artificial muscle is successfully used to demonstrate mimicry of eye motions including eyelid blinking and eyeball movement in a doll.