Cold Atmospheric Pressure Argon Plasma Jet Assisted Degradation of Malachite Green (MG) Aqueous Solution

The oxidative degradation of cold atmospheric pressure plasma assisted degradation of malachite Green (MG) was investigated in this study. Cold atmospheric pressure plasma assisted MG degradation process was carried out as a function various plasma treatment time (05, 10, and 15 mins). The % of degradation and presence carbon content in the plasma treated MG was examined by UV-Visible spectroscopy (UV-Vis) and total organic carbon (TOC) analyzer. Optical emission spectrometer was used to identify formation of various reactive species during in situ plasma treatment. The higher degradation percentage of 90% was obtained after plasma treatment time of 15 min and value of TOC also found to decreased significantly with increasing plasma treatment time.  Toxicity of the plasma-treated MG aqueous solution samples was also examined by Staphylococcus aureus (S.aureus) bacteria

Development of phosphor containing functional coatings via cold atmospheric pressure plasma jet - Study of various operating parameters

In this study, we deposited phosphorous containing functional coatings on the surface of polypropylene (PP) substrate by cold atmospheric plasma assisted polymerization using low temperature plasma jet. Triisopropyl phosphate (TIP) was used as precursor while the coating process was carried out as a function of deposition potential and monomer flow rate. The influence of various plasma polymerization operating parameters on the surface properties of functional coatings are examined by means of atomic force microscopy (AFM), Scanning electron microscopy (SEM) and X-ray photo electron spectroscopy (XPS). The reactive species involved during the in-situ polymerization were studied by optical emission spectroscopy (OES). The variation in hydrophilic properties of the surface coated film was investigated by measuring contact angle. Furthermore, the stability of post-plasma polymerized films was evaluated by measuring contact angle values 15 days after storing in various ambient conditions (air and distilled water). The characterization results clearly exhibited that phosphorus containing functional films could be successfully deposited on the surface of PP films and the retention of the functional groups could be tuned within the framework of the operating parameters

Atmospheric pressure non-thermal plasma assisted polymerization of poly (ethylene glycol) methylether methacrylate (PEGMA) on low density polyethylene (LDPE) films for enhancement of biocompatibility

This study focuses on the polymerization of poly (ethylene glycol) methylether methacrylate (PEGMA) on LDPE films via atmospheric pressure non-thermal plasma (APNTP) to enrich their biocompatibility. The influence of the discharge potential and the deposition time on the changes in surface properties of plasma polymerized PEGMA films has been studied through X-ray photoelectron spectroscopy (XPS), static contact angle (CA) measurements and atomic force microscopy (AFM). An increase in surface hydrophilicity, surface free energy and roughness was observed after the deposition of the PEGMA-based films. It was found that the higher concentration of characteristic ether groups (CO) are incorporated on the surface of PEGMA films deposited at higher discharge potentials and deposition time, as confirmed by XPS analysis. Increasing the discharge potential and deposition time were responsible for substantial changes in surface chemical composition, topography and film thickness. Finally, in-vitro analysis was used to examine the alterations in antifouling efficiency and cytocompatibility of the plasma polymerized PEGMA films. Films deposited at a discharge potential of 14 kV for 5 min were found to give the highest antifouling efficiency and cell viability, when compared to the films deposited at other discharge potentials and deposition times. Thus, by choosing suitable plasma parameters, the properties of the deposited films can be tailored to enhance the biocompatible properties of LDPE films

Late Middle Miocene volcanism in the Northern Borneo, Southeast Asia: Implications for tectonics, paleoclimate and stratigraphic marker

International audienceExplosive volcanic events often produce pyroclastic materials that can be recognized from the geological record. These discrete pyroclastics form regional marker beds. Here we report the occurrence of a tephra layer interbedded within very thick coal beds near Mukah, Sarawak, Borneo. Traceable for tens of kilometers in the Mukah area of Sarawak, this tephra layer can be considered as regional stratigraphic marker with precise chronostratigraphic control. Systematic sedimentological, mineralogical, geochemical and zircon UPb geochronological studies have revealed a major effusive volcanic event during the latest Middle Miocene, presumably contemporaneous and/or related to a magmatic event of an earlier phase of the Mt. Kinabalu pluton or magmatism in West Sarawak or East Sabah. The volcanic event had promoted catastrophic flooding of coastal swamps and fall-out from the ash clouds that formed a regionally monotonous tephra layer across the Serravallian- Tortonian boundary. In conjunction with the regional occurrences of trap rocks, structural trends and known tectonic events, we constrained the regional depositional environments, and climate. The tephra layer was deposited in a coastal plain-swamp,- seasonal, shallow, high-moderate energy, fluvial channel-lacustrine environmental setting, wherein atmospheric fallout and eroded material from regoliths formed over older basement and volcanic rocks of the hinterland which were mixed to produce the tephra layer. This tephra layer is sandwiched between the very thick coal beds. A pre-existent volcanic chamber that was active for a long time, also experienced periodic explosive activity from probably the same magma chamber and conduit and including a major explosive activity that recycled early-formed crystals and felsic magma (rhyolite-dacite) during the major effusive event are also recognized. Our findings provide robust evidence for the prevalence of intensive chemical weathering under a wet-humid climate, and relative tectonic quiescence before the major effusive event, and the existence of vast, monotonously gently-sloping coastal plains and luxuriant vegetation akin to the present