Plasma-induced Decolorization of Indigo-dyed Denim Fabrics Related to Mechanical Properties and Fiber Surface Morphology

The aim of this study was to investigate how morphology of fibers is affected by plasma during the process of decolorization by a low-pressure RF plasma (gas, treatment time, and power were varied) and atmospheric pressure industrial corona (number of passages and power). CIE LAB colorimetric system was used for determination of color difference between untreated and differently plasma-treated denim fabrics. Particular emphasis was put on the morphological changes induced by plasma treatment, because they indicate changes in mechanical properties of the fabrics. The morphology of plasma-treated fibers was analyzed by scanning electron microscopy (SEM). SEM images revealed that, when plasma conditions that lead to a decolorization were chosen, specific fiber surface changes were always observed in the form of submicrometer-sized striations, pits, and cracks. Mechanical properties of denim fabrics were moderately influenced by treatment conditions. The results indicated that decolorization was highly affected by plasma parameters and desired worn look effects could be designed by adequate control of plasma processing while paying attention to limiting the plasma-induced damage

The stimulatory effect of non-equilibrium (low temperature) air plasma pretreatment on light-induced germination of Paulownia tomentosa seeds

Light-induced germination of Paulownia tomentosa seeds was used as an experimental system to investigate the effect of pretreatments by non-equilibrium (low temperature) air plasma on the germination process. Dry P. tomentosa seeds exposed to the plasma changed their germination characteristics. Non-equilibrium plasma treatments significantly increased the light sensitivity of P. tomentosa seeds. These treatments could not substitute for the light-requirements of the seeds. After a short exposure to plasma (4 to 6 minutes) treated seeds had a germination of 75%, i.e. significantly higher than the 5-30% for seeds which did not undergo pretreatment. The results suggest that the stimulatory effect of the non-equilibrium air plasma pretreatment is not a direct photoreceptor-mediated phenomenon. Possible mechanisms of this effect are discussed.nul

Removal of metal cations from wastewater using recycled wool-based non-woven material

In this study, the effect of low-temperature air plasma, biopolymer chitosan and hydrogen peroxide treatment of recycled wool-based non-woven material on metal cation uptake was investigated. Recycled wool-based material either as an untreated or modified material showed ability to bind all investigated metal cations in the following order: Pb2+>Cu2+>Zn2+>Co2+. Material performed good selectivity due to distinct sorption rates of studied metal cations.U ovom radu je ispitan uticaj obrade netkanog materijala na bazi vune kao sekundarne sirovine niskotemperaturnom plazmom, biopolimerom hitozanom i vodonik- peroksidom na sorpciju katjona metala. Materijal na bazi vune kao sekundarne sirovine bilo kao neobra|en ili modifikovan, poseduje sposobnost vezivawa katjona metala prema slede}em redosledu: Pb2+>Cu2+>Zn2+>Co2+. Materijal pokazuje dobru selektivnost usled razli~ite brzine sorpcije ispitivanih katjona metala

Removal of metal cations from wastewater using recycled wool-based non-woven material

In this study, the effect of low-temperature air plasma, biopolymer chitosan and hydrogen peroxide treatment of recycled wool-based non-woven material on metal cation uptake was investigated. Recycled wool-based material either as an untreated or modified material showed ability to bind all investigated metal cations in the following order: Pb2+>Cu2+>Zn2+>Co2+. Material performed good selectivity due to distinct sorption rates of studied metal cations

Measurements of voltage-current characteristics of a plasma needle and its effect on plant cells

In this paper we present voltage-current-power characteristics of a plasma needle operating in the flow of helium at atmospheric pressure. In addition, we show some examples of how such a plasma affects plant tissues. In the characterization of the plasma needle, current and voltage waveforms were recorded by two derivative probes. These two probes are similar to the probes previously used by Puac et al for measuring transmitted power in low pressure CCP rf discharge. The instantaneous power was calculated from current and voltage waveforms and U-I characteristics of the discharge were determined. Regimes of operation with and without the grounding ring at the tip of the needle were considered. We have chosen two model systems to study the effect of the plasma needle on plant cells and tissues: sweet fern gametophyte (prothallus) and calli produced in vitro. Since the prothallus consists of a single layer of cells, the cytological effects could be easily examined. In addition, calli and prothallus are easy to manipulate and in vitro culture provides a possibility to work under constant and controlled conditions.nul

Measurements of voltage-current characteristics of a plasma needle and its effect on plant cells

In this paper we present voltage-current-power characteristics of a plasma needle operating in the flow of helium at atmospheric pressure. In addition, we show some examples of how such a plasma affects plant tissues. In the characterization of the plasma needle, current and voltage waveforms were recorded by two derivative probes. These two probes are similar to the probes previously used by Puac et al for measuring transmitted power in low pressure CCP rf discharge. The instantaneous power was calculated from current and voltage waveforms and U-I characteristics of the discharge were determined. Regimes of operation with and without the grounding ring at the tip of the needle were considered. We have chosen two model systems to study the effect of the plasma needle on plant cells and tissues: sweet fern gametophyte (prothallus) and calli produced in vitro. Since the prothallus consists of a single layer of cells, the cytological effects could be easily examined. In addition, calli and prothallus are easy to manipulate and in vitro culture provides a possibility to work under constant and controlled conditions.nul

The impact of educational reform and categorization of scientific journals and scientists on physics in Serbia

The trend of the increasing participation and importance of female physicists in Serbia continues. Many women have taken leading position in research and faculty governance and are contributing significantly to educational reform and the improvement of physics education in the primary and secondary schools. © 2013 American Institute of Physic