Growing awareness for occupational safety in the welding environment needs a sustainable welding system. Welding gases releases toxic tiny particles and gases that inflict severe health consequences in the weld zone are unsolicited. Some of the other main adverse effects are lung disease, hemoptysis, pulmonary inflammation, pneumoconiosis, etc. GMAW procedure has been used for welding 316L stainless steel plates of 3 mm, 5 mm, and 6 mm. Various current configurations with gas flow rate of 5 LPM, 10 LPM and 15 LPM were also used to achieve optimum butt joint performance and to reduce the production rate of fume contributing to cost-effectiveness. In this research a cost-effective fume extraction hood was fabricated for measuring emission factor produced during welding. Various shielding gas compositions including Pure Argon, Pure CO2, 92% Ar+8% CO2 and 88% Ar+12% CO2were used to determine the best operating parameters in the GMAW method. To satisfy the latest Permissible Exposure Limit (PEL) legislation, optimum technical parameters for efficient welding were acknowledged with the lowest emission factor. A maximum reduction of emission factor can be achieved by using Pure Argon. The inclusion of CO2 as a shielding gas mixture gives higher emission factor when compared to Pure Argon. Very low emission factor were witnessed in this research when compared to previous investigations. Lower emission factor of 2941.17 mg /kg of electrode, 4411.76 mg/kg of electrode and 7352.94 mg/kg of electrode were obtained for pure argon as shielding gas with 150 A welding current.
In this study, a new chemically modified cellulose polymer-capped ZnO nanopowder prepared by hydrothermal method using chemically modified cellulose polymer as capping agent was successfully reported. The structural characteristics of CMC-capped ZnO nanopowder was reported by FTIR, XRD, SEM and EDX studies. XRD results revealed crystallographic properties like crystal composition, phase purity and crystallite size of the prepared CMC-capped ZnO nanopowder and average size calculated by Debye Scherrer formula as 14.66 nm. EDX studies revealed that the presence of elemental compositions of capping agent in the nanopowder samples. The optical characterization of the CMC-capped ZnO nanopowder was studied using UV absorption (λ max = 303 nm) and PL spectroscopy (λ ex = 295 nm). The average crystal diameter and grain size were calculated by effective mass approximation formula and compared with XRD findings that agreed well and verified CMC capped ZnO with particle size of 193 nm. Thus, the promising optical characteristics shown by the synthesized CMC capped ZnO nanopowders exposes its potential usage in bio-medical fields.
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