120 ± 5 gsm para-aramid was used as base fabric and coated with four barrier chemicals viz; NR, PU, Neoprene and Hypalon to make 300 and 500 gsm (±5 %) weight coated fabrics and coating was carried out on both sides using Doctor Blade method . All eight samples were tested by UL-94 V  and NFPA-701 methods  and results were compared with base fabric.
UL-94 V test
 UL-94 vertical test is one of the important FR tests routinely carried out to assess the self-extinguishing time of vertically suspended materials. Cotton wad (or surgical cotton) is placed below burning sample to observe dripping. The substrates are rated (Table 1) based on following observations;
V-0 - Dripping is not observed and flame extinguishes within 10 s.
V-1 - Dripping is not observed and flame extinguishes within 30 s.
V-2 - Dripping is observed but flame extinguishes within 30 s.
In this research, inherently flame-retardant base fabric viz, para-aramid (or Kevlar or Twaron) was coated with four barrier chemicals. Out of four barrier chemicals, two chemicals burned readily and two offered flame resistance due to presence of chlorine atom in their polymeric chain. In our experiments the coated fabrics were taken in increasing coating thickness (and hence weight) viz; 300 and 500 gsm. The coated fabrics were subjected to UL-94 V and NFPA-701 tests to know the best FR
CRediT authorship contribution statement
RG Revaiah: Methodology, Validation, Writing – original draft. TM Kotresh: Conceptualization. Balasubramanian Kandasubramanian: Supervision, Writing – review & editing.
Declaration of Competing Interest
The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.
The authors thank Director General Life sciences and Vice Chancellor, DIAT, Pune for constant encouragement.
Uranium(VI) remediation from aqueous environment using impregnated cellulose beads
Journal of Environmental Radioactivity, Volume 136, 2014, pp. 22-29
Use of cellulose based adsorbents for post treatment of contaminated water provides significant removal and recovery of trace quantities of radioactive and highly toxic U(VI) ions. Efficiency of the adsorbent was enhanced by impregnation of nano Fe2O3. Variables considered for obtaining optimized process conditions were solution pH, adsorbent dosage, initial metal ion concentration, additive content and contact time. The batch adsorption study revealed highly pH dependent adsorption with 100% adsorption efficiency at pH 7 using 1.5g of adsorbent impregnated with 6wt% Fe2O3 for 50mL solution capacity in 150min. The adsorption capacity was noted to be 7.6mg/g. The adsorption mechanism was studied at pH 7 maintained using dilute ammonia solution to prevent the effect of any interfering cation. Uptake of U(VI) was found to be predominately via an intraparticle diffusion mechanism following pseudo second-order kinetic model, which is clearly reflected from the non-spontaneous thermodynamics yielding a positive free energy value. Recovery of the adsorbed U(VI) ions was highly feasible using 0.05N HNO3 and the regeneration of the adsorbent using 0.01N NaOH.
Chemical reactive magnetized fluid flow through a vertical channel due to heat source and thermal radiation effects
Materials Today: Proceedings, Volume 78, Part 3, 2023, pp. 481-492
Chemical reactive magnetized fluid flow through a vertical channel of infinite thin walls occupied with the permeable substance in the presence of heat source and thermal radiation with suction/injection at the walls is deliberated in the present research paper. The characteristic equations of fluid velocity, heat and mass transfer are emanated and their analytical solutions are extricated by using the Homotopy Perturbation Method (HPM). The consequence of the assorted fluid parameters on flow have been depicted through figures, and shear stress, heat and mass transfer rate have been calculated and presented in tables. It is discerned that growth in the chemical reaction helps to decrease the velocity, temperature and concentration profile. Further, it is observed that the heat and mass transfer rates are improved at the moving wall of the channel with the growth in the chemical reaction, and this analysis is useful in the study of food processing, packet bed reactors in chemical industries, and heat exchanger and heat storage devices, thermal engineering etc.
Enhanced dielectric properties of the ZnO nanoparticles dispersed PU/PANI blend nanocomposites
Materials Today: Proceedings, Volume 74, Part 4, 2023, pp. 681-687
Dielectric systems composed of conductive polymers and metal oxide nanoparticles become the most frontier hybrid materials to be used in various electronics for their superior dielectric characteristics and easy processibility. In the present study, the effects of conducting polyaniline (PANI) and Zinc Oxide (ZnO) nanoparticles on the dielectric characteristics like dielectric constant (ε′), loss factor (ε″), current permitting ability (σac), both real and imaginary impedance (Z′ and Z″), Nyquist plots, etc., have been explored. The prime objective is to explore the effect of ultra-low loading levels of ZnO nanoparticles on the significant improvement in the dielectric relaxation behavior. Prior to the dielectric analysis, the dispersion pattern of ZnO nanoparticles in the bulk of TPU/PANI phases has been analyzed from the microphotographs obtained from the field emission scanning electron microscopy (FESEM) as well as high-resolution transmission electron microscopy (HRTEM) analysis. The analysis of the frequency of the applied electric field's effects (1 to 106 Hz) on the dielectric characteristics shows that the produced hybrid materials may be used in a variety of applications. The variation of the aforesaid parameters with change in temperature is also explored which informs the suitability of the hybrid system in the manufacturing of high-temperature sensing applications. Significant improvement in the dielectric properties at 0.1wt% loading level of ZnO is the novelty of this present analysis. The predominance of ε′ over ε′′ after a certain frequency of the applied field ensures the electric energy storing ability of the systems rather than energy loss. The reduced area under the Nyquist plot informs the approach of the system from an insulator to a perfect dielectric material that can be used in a capacitor for electric energy storage purposes.
Development and physico-chemical characterization of thermally treated spent turmeric root waste to treat dye containing wastewater
Materials Today: Proceedings, Volume 77, Part 1, 2023, pp. 125-129
This study focuses on the potential application of turmeric root waste as an adsorbent to treat dye-based wastewater. The spent turmeric root (STR) waste is carbonized at 260°C to obtain biochar (STR-BC). The TGA analysis reveals a higher thermal stability for STR-BC (up to 500°C) than STR (up to 200°C). XRD analysis implies that STR-BC is more amorphous. FE-SEM analysis shows more porous structures in STR-BC than in STR. The obtained STR-BC is also used to treat synthetic wastewater containing methylene blue. For this treatment, the maximum dye removal is found to be approximately 97%.
DMOGA on performance measures of WEDM for titanium matrix composite
Materials Today: Proceedings, Volume 78, Part 3, 2023, pp. 469-475
Conventional machining of titanium matrix composite (TMC) is very intricate for its superior strength-to-weight ratio and resistance to fatigue and corrosion. The novelty lies in the analysis of multi-objective genetic algorithm (MOGA) coupled with desirability, forming desirable multi-objective genetic algorithm (DMOGA) of wire electro-discharge machining (WEDM) machining characteristics of performance measures varying power (P), peak current (IP) and time-off (Toff). In this paper, investigation is carried on design of experiments (DOE) on performance measures like material removal rate (MRR), surface roughness (SR), kerf width (KW) and over cut (OC) and reasonable results are attained and authenticated by confirmatory test. Optimality is attained when P is 7.37W, Toff is 27.87µs, IP is 9.71 A, MRR is 3.61mm3/min, SR is 1.39µm, KW is 0.35mm, OC is 0.09mm and combined desirability is 0.72.
Electronic properties of Poly(1,6-heptadiynes) electrospun fibrous non-woven mat
Materials Chemistry and Physics, Volume 223, 2019, pp. 343-352
The poly(1,6-heptadiynes) structure induced conductivity was perceived in the range of 534–577 nm corresponding to the 2.2eV mean photon energy absorption via UV–visible spectroscopy. Further the conductivity was realized by investigating AC-conductivity of poly(1,6-heptadiynes) via two-probe measurement enabled impedance spectroscopy. The demonstrated mean frequency independent conductivity was about ∼3.8*10−4S/cm (101–107 Hz). Electrospun technique was utilized to fabricate fibrous non-woven mat (0.1w-0.3 wt% of poly(1,6-heptadiynes)) with the aid of engineering thermoplastic Acrylonitrile Butadiene Styrene (ABS) via solution blending, which facilitate the processability and mechanical stability to the poly(1,6-heptadiynes) to accelerate electronic application design. The morphological, conductivity and permittivity measurements were performed on electrospun fibrous non-woven mat. The observed ingenious conductivity was about ∼1.1*10−5 S/cm at 107 Hz, which was due to enhanced surface area of fibers via electrospinning and poly(1,6-heptadiynes) intrinsic conductivity. Further the conductivity was elucidated by investigating permittivity characteristics. The permittivity results suggest that the diminishing response while adding different poly(1,6-heptadiynes) wt% configurations, which is due to the significant intrinsic conductivity of poly(1,6-heptadiynes). Moreover, the permittivity characteristics 103–107Hz attributes to micro/nanocapacitor Maxwell Wagner Sillars (MWS) and dipolar polarization mechanism.
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