Papers by Keyword: Contamination

Abstract: This paper addresses the study of hydraulic oil degradation, the increase in the number of wear metals, and contaminants in the monitored oil sample during 6 months of operation of an agricultural tractor. In a closed hydraulic circuit, the oil undergoes gradual degradation due to operational influences, which is caused not only by contamination from external impurities but also by the mixing of operational fluids from other attachment devices. Chemical analysis, water content measurements, and ferography were conducted on a sample of HARVELLA TX 10W40 hydraulic oil, which was compared with a sample of new, uncontaminated oil. The condition of operational fluids affects the proper functioning and lifespan of hydraulic circuit components and is one of the diagnostic indicators of their wear. During the operation of the equipment, the mixing of hydraulic oil from the main device and attachment devices occurs, resulting in changes to the operational properties of the fluid. The study compared the state and contamination of the mixed fluid in the tractor's internal hydraulic circuit with the hydraulic fluid applied by the manufacturer in new equipment. The measurement results indicated that during the experiment, no significant contamination of the oil occurred from pollutant elements present in the external environment, and the physicochemical properties of the monitored fluid were not significantly reduced.

Abstract: Clarifying the distribution of cadmium (Cd) and lead (Pb) in the soil of Hainan's Se-rich areas will not only provide a basis for the healthy and sustainable development of Hainan's Se-rich industry, but also provide ideas for Hainan's agricultural and food safety research. Using a method that combines field investigation and indoor analysis, with the help of geostatistics and spatial analysis technology, the concentration of Pb and Cd in the soil and rice in the area were studied. The Cd in the cultivated soil layer of the arableland in the area is lower than the first-level standard of our country's soil environmental quality standards, and the soil Pb content is slightly higher than the first-level standard. The overall ecological risk is low. Pb and Cd in polished rice are 0.14 and 0.11 mg/kg respectively. The concentrations distribution of lead and cadmium in rice is: straw > polished rice. Heavy metals are more likely to accumulate in non-edible parts such as straw.

Abstract: The study evaluates the method of investigation of soil contamination with heavy metals at the sites of explosions. Results of method application were obtained. Soil samples were collected in location selected as the typical place were explosions take place for explosive objects destruction. For the qualitative and quantitative analysis of soil samples, the "KBr tablets" method was used. Obtained pellets were investigated with spectral-analytical installation created on the basis of infrared-spectrometer IKS-21 and thermal imager LAND-814. IR spectrometric research was carried out in the most informative spectral range of wavelengths of 7.5...14 μm. Proposed method of investigation of soil contamination with heavy metals at the sites of explosions allowed to identify presence of such metals as Al, Cu, Fe, Mg, Ni and Zn in soil samples of explosion site. Mg, Ni and Zn show stable presence in the soil of explosion site with low amount. Al, Cu and Fe we have seen sharp decrease of logarithmic transmittance value at the depth of 10…15 cm which means that these elements are accumulated at these depths of soil after explosions.

Abstract: Poly(lactic acid) or PLA is one of the most important biodegradable plastics that replaces petroleum-based plastics for transparent disposable packaging. For circular economy, the accumulated PLA waste is required to recycle to produce high-quality recycled PLA grades. This research was aimed to simulate the influence of PET contamination (0.5, 1.0 and 2.0 wt%) on properties of the recycled PLA. Two grades of PLA; extrusion and injection molding, were used, and two temperature conditions (180 and 250°C) were used to evaluate the influence of mechanical recycling condition. Mechanical and thermal properties of the recycled PLA were investigated using tensile and impact testing, and differential scanning calorimeter, respectively. It was found that the mechanical recycling at 180°C produced the transparent specimens having unmolten white PET defects, which the mechanical properties were still intact with the PET contamination up to 1 wt%. The mechanical recycling at 250°C produced the opaque specimens with significantly lower mechanical properties due to the chain scission of PLA molecules, and the impact strength was slightly improved due to transesterification. The results could be used to emphasize the importance of the sorting step that the PLA recycling process should be performed with the PET contamination less than 1 wt%.

Abstract: Mucuna pruriens is a tropical leguminous plant containing L-dopa which is the main active ingredient for Parkinson’s disease therapy. The objective of this study was to investigate the physical, chemical, and microbiological stability of M. pruriens seed extract effervescent powders and suspension. The effervescent powders and suspension were prepared using freeze dried M. pruriens seed extract and were stored at 4 °C, 30 °C, and 45 °C. Physical stability was evaluated by observing appearance and determining rheological behavior. Chemical stability was evaluated by HPLC assay of L-dopa content in the formulation. Bacterial, fungal and mold contaminations were assessed by 3M^TM Petrifilm^TM count plates. Both formulations showed good physical stability. The degradations of L-dopa in effervescent powders and suspension were fitted to pseudo-zero order and second order kinetic models, respectively. M. pruriens seed extract effervescent powders was found to have the longest half-life, about 112 days, when it was stored at 4 °C. The results suggested that M. pruriens seed extract should be formulated in effervescent powders and stored at 4°C to prevent physical and chemical degradation.

Abstract: This study focuses on investigating the impacts of kerosene on the physical, mechanical, and chemical characteristics of clay soil. The soils specimens are contaminated artificially with six ratios of kerosene (5, 10, 20, 30, 40, and 50) % calculated according to the dry weight of soil. The artificial contamination includes air drying of the disturbed soil, then placed in plastic containers and mixed with the field water content and the specified concentration of kerosene to ensure getting homogenous contaminated soil specimens. The contaminated soil specimens left for 30 days in plastic containers covered by nylon sheets to control the water content and prevent volatility of contaminant. The results of tests proved that different ratios of kerosene have different impacts on the engineering and chemical characteristics of soil specimens. The specific gravity, percentages of fine particles, optimum water content, the initial and final void ratio, coefficient of consolidation, swelling index, permeability, the undrained shear strength, effective shear strength parameters, and the rate of reduction of initial pore water pressure are reduced significantly with increasing the content of kerosene in soil. Generally, the concentration of kerosene less than 10% has slight impacts on the studied characteristics of soil specimens.

Abstract: Contaminated land is a legacy of industrial revolution as a result of rapid growth of industries. Since long back, the disposal of liquid and solid wastes on land though undesirable, has been in practice. The leachate generated out from these hazardous wastes infiltrates into the ground and causes multiple problems viz., ground water pollution, soil pollution, loss of nutrition value of soil and thereby severe damage to plantation growth, changes in the soil behavior (excessive swell/shrink) depending on the nature of waste. It also causes serious distress to the existing structures such as pavements, foundations, underground pipelines and culverts. The changes in the soil behaviour caused by ground contamination can lead to structural failures. The present paper describes various physical, chemical, biological, thermal and solidification/stabilization methods of soil and ground water remediation and their comparison on the basis of applicability, time and cost.

Abstract: The process of manufacturing polymeric material products includes the entire processing system; from their properties and the technical level of the manufacturing device, through its control and regulation system, and the manufacturing tools. This article deals with the study of aluminium alloy materials used in the manufacture of moulds - with different coatings, in order to reduce the surface contamination of the cavity moulds. The reason for choosing this topic is to discover a way as to how to understand the contamination process. The method chosen for eliminating such contamination is then, dependent on the degree of knowledge regarding the state and cause of the problem in the production process under investigation.

Abstract: The corrosion on glass surfaces causing contamination in the aqueous solutions depend on pH and temperature. This research aims to study the elements leached from the inner glass surfaces that were treated and untreated to aqueous solution. The clear and amber bottles used as the samples were determined the chemical composition by XRF. The samples were treated with 2%, 3% and 5% alum solutions and the hydrolytic resistance test was performed according to ISO 4802-1. The results showed that bottles treated with 3% alum solution gave the most suitable condition to improve the hydrolytic resistance. The treated and untreated bottles were filled with 2% citric acid solution, RO water, and 0.9% sodium chloride solution and kept at 20 and 40°C for 0.125, 1, 2, 4, 10, 20, 40, 60 and 120 days. The pH values of all solutions after ageing were measured and the leached elements – Na, Ca, Al, Cr, Mn, and Pb – in RO water and citric solution were analyzed by AAS. There was significant increase of pH with time at 40°C within 10 days before it had slightly rose to nearly 9.7 of both treated and untreated bottles. However, samples filled with citric solution shows no change in pH value. Na leached from the untreated samples which showed the highest concentration at 2.3 ppm from clear glass and 4 ppm from amber glass respectively. Other elements were not found.

Abstract: Lead (Pb) is one of common heavy metal that has been shown to be very useful tracers of environmental pollution. The consequences of urbanization process can cause not only economic growth but also negatively impact on the quality of water and soil. Therefore the objective of this research is to know the potential contamination of lead in soil of urban area. The soil samples were conducted by batch leaching experiment. In surface soil, lead in soil of Pakem area varies from 2.01ppm to 5.13 ppm with average value of 3.02 ppm and Merapi area ranges from 1.84 ppm to 3.41ppm with average value of 2.42 ppm. In urban area, lead varies from 4.18 to 14.88 ppm with average of 9.93 ppm. Lead in urban soil is higher than Pakem and Merapi soil. The potential contamination of lead in urban soil is occurred with respect to urbanization and human activities. The value of lead is shown with the average of 3 ppm for Caturtunggal, Depok District, 6.53 ppm in Mantrijeron District and 9.82 ppm for Kotagede District in Yogyakarta city. The result of lead distribution in Kotagede District is the highest concentrated and it is followed by Mantrijeron District and Caturtunggal, Depok District.