Cotton canvas trousers washing: an inception of a new horizon in apparel industry

Nowadays, fashionable trouser (denim) with washing effect is very popular, especially among the youth. The global fashion trend has led to the development of diverse washing processes that are predominantly applied to denim fabric. However, no known research has studied the application of the washing effect on canvas fabric. Therefore, this paper aims to make fashionable canvas fabric trousers by applying various washing effects. To do so, ready-to-dye canvas fabric trouser was constructed, then dyed with dischargeable reactive dye (Lava). Chemical washing processes such as whisker, enzyme, and PP spray were then applied on dyed canvas trousers. Finally, developed samples were being characterized by mechanical tests such as tensile strength, tear strength, stiffness, abrasion, pilling, colorfastness to wash, and colorfastness to rubbing. Besides, to evaluate fabric surface, various tests such as Scanning Electronic Microscope (SEM), Reflectance% values have also been characterized. Tensile strength, tear strength, stiffness, reflectance% value, and wear index% changed significantly for every subsequent process. The tensile strength of finished trousers was 489.87 N at warp and 350.57 N at weft direction and the tear strength was 48.01 N and 35.56 N at warp and weft direction, respectively. The reflectance% value of 18.74 was observed at the PP sprayed area. Overall, the research revealed the possibility of using cotton canvas as a pair of fashionable trousers contributing to the development of the apparel industry.

Recent Advances in Pre-Treatment of Plastic Packaging Waste

There is an urgent need to close the loop of plastic waste. One of the main challenges towards plastic packaging waste recycling is the presence of a variety of contaminants. These contaminants include organic residues, additives, labels, inks and also other plastic types that can be present in the waste stream due to missorting or in multimaterial structures (e.g. multilayer films in packaging). In this context, pre-treatment processes are a promising route to tackle the difficulties that are encountered in mechanical and chemical recycling due to these contaminants. This chapter gives better insight on the already existing pre-treatment techniques and on the advances that are being developed and/or optimized in order to achieve closed-loop recycling. Some of these advanced pre-treatments include chemical washing to remove inks (deinking), extraction methods to remove undesired plastic additives and dissolution-based pre-treatments, such as delamination and dissolution-precipitation techniques.

A Complete Control System for a High Voltage Converter in an Electrostatic Precipitator

Nowadays, the emission of pollutant particles is a global problem in terms of limiting pollution in industries, as well as greenhouse gases emissions. There are different ways to filter undesired particles, such as carbon air filters, chemical washing, and so on. One of the most popular techniques is the use of electrostatic precipitators: The operation mode is based in attracting particles using electrostatic forces. In order to do that, it is necessary to use a high-voltage converter, with a relative complex control. This article deals with the design of a complete platform to control not only these kind of converters, but also those converters based on the full-bridge power topology.

Feasibility of a Chemical Washing Method for Treating Soil Enriched with Fluorine Derived from Mica

High levels of fluorine in soil may pose health risks and require remediation. In this study, the feasibility of using a practical chemical washing method for the removal of fluorine from an enriched soil was evaluated. The chemical washing procedures were optimized through experimental analyses of various washing solutions and washing conditions (i.e., washing solution concentration, solid–liquid ratio, agitation speed, and reaction time). Additionally, the effects of techniques for improving the washing efficiency, such as ultrasonic washing, aeration, and multi-stage washing, were evaluated. Herein, among all applied methodologies, the maximum washing efficiency achieved for the total fluorine present in soil was only 6.2%, which indicated that chemical washing was inefficient in remediating this particular soil. Further sequential extraction analysis showed that the fluorine in this soil was present in a chemically stable form (residual fraction), possibly because of the presence of mica minerals. It was demonstrated that chemical washing may not be effective for remediating soils containing such chemically stable forms of fluorine. In these cases, other physical-based remediation technologies or risk management approaches may be more suitable.

Changes in Soil Properties after Soil Washing of Metal-contaminated Soil near the former Janghang Smelter

Objectives : Changes in soil properties after washing of metal-contaminated soil near the former Janghang Smelter were investigated in this study. Contaminated input soils and remediated output soils were sampled from three different soil washing plants and analyzed for soil physical and chemical properties. Soil quality was evaluated by the soil fertilization guideline suggested by the Korea Rural Development Administration (KRDA). This study revealed the necessity of soil quality management for the remediated soil as an ecosystem member.Methods : Three soil washing plants (1OU, 2OU, 3OU) were commonly divided into the five steps: 1) the particle separation (crushing and grinding etc.) → 2) soil particle classification (big stone, fine soil, minimal fine soil) → 3) chemical washing (fine soil) → 4) neutralization of washed soil (lime) → 5) return-back to the original position. The separating minimum particle diameters of the 1OU, 2OU, and 3OU washing processes were 5 µm, 20 µm, and 10 µm, respectively, and the chemical washing solutions used were respectively 0.1 M H2SO4, 0.5 M H2SO4/0.5 M H3PO4, and 0.1 N NaOH-Na2CO3 (alkali reduction). Soils were collected before and after washing, air-dried, sieved with < 2 mm and analyzed for soil texture, bulk density, aggregate stability (AS), water holding capacity (WHC), pH, electrical conductivity (EC), organic matter content (OM), total nitrogen (TN), available phosphate (AvP), cation exchange capacity (CEC), exchangeable cations (potassium, calcium, magnesium, sodium).Results and Discussion : Sandy soil showed a big change in soil texture before and after soil washing, while there was no change in soil texture for fine soil. Sandy soil showed an increase in bulk density, a decrease in WHC, and a decrease in AS. The pH of remediated soil was affected by the type of washing chemical. The acidic washing processes (1OU, 2OU) resulted in low pH soils, while an alkali reduction process (3OU) showed high pH soil. The soil OM, TN, AvP and CEC decreased after soil washing. In the case of silty paddy soil, OM and TN were significantly reduced by washing. The most important change in soil property after washing was EC. After soil washing, the soil electrical conductivity increased sharply in all OUs : 1OU 0.51 → 6.21 ds/m, 2OU 1.09 → 3.73 ds/m, 3OU 0.99 → 9.30 ds/m. The EC values of the contaminated soil before washing were all less than 2 ds/m, which is an appropriate agricultural level. However, EC was significantly increased after washing, implying a strong salty soil level. The soil quality evaluation results before and after washing showed that the soil quality of heavy-metal contaminated soil was apparently degraded by washing. The number of soil property in the optimal range before washing (contaminated soil) was 10, but the number decreased to 5 after washing (remediated soil).Conclusions : Soil quality may be significantly changed after soil washing. The most noticeable change was the significant increase in the EC of soil and the soil health should be restored first to recycle the remediated soil. The important causes of changes in the soil quality were the separation of fine soil particles containing relatively high heavy metals from the bulk soil, soil disturbance by chemical washing solution and addition of high salts such as coagulants and pH adjust. Soil management schemes considering soil health should be soon prepared to restore the remediated soil back as an ecosystem member.