HAZARDOUS PROPERTIES OF BROMINATED, PHOSPHORUS, CHLORINATED, NITROGEN AND MINERAL FLAME RETARDANTS IN PLASTICS WHICH MAY HINDER THEIR RECYCLING

Flame retardants are numerous and some of them are (re)classified with time as hazardous for the man and the environment. A list of 69 flame retardants used in EU was set from three sources and their chemical properties were searched in their registration dossier at ECHA. Substance self-classifications (hazard statement assignment by the registrant) frequently indicate no hazard or data not available, while for the same substances a re-evaluation by ECHA is underway as persistent, bioaccumulative, toxic or endocrine disruptor. When the substance has hazard statement(s), the concentration that triggers the classification of a plastic as hazardous when it is a waste can be compared to the functional concentration, when available. Registration dossiers should be completed for the many “non-available” information. Of these 69 substances, 12 (= 17%) are used at concentrations greater than those making plastic waste hazardous and 13 (= 19%) are under re-evaluation by ECHA. These 12 or 13 substances should not become “legacy” substances which hinder the recycling of plastics. The sorting (mainly by density) and management options of these flame-retarded plastics are discussed. The technical concentration limit of 2000 mg total Br/kg for sorting should not be modified as it includes all organobromine substances currently reassessed by ECHA. A two-step sorting process is necessary to avoid the loss of non-hazardous dense plastics.

Review of an experiment to study the propane discharge in a closed production area

В статье представлены результаты экспериментальных исследований истечения пропана в различных направлениях в закрытом помещении. Рассматривался случай, когда источник истечения находился в багажнике автомобиля - имитация нахождения автомобиля с газомоторным топливом на станции технического обслуживания. Целью эксперимента являлось изучение механизма пространственного распространения газа в закрытом помещении для валидации математических моделей, используемых в программном комплексе ANSYS Fluent при моделировании поступления пропана в закрытое помещение. This scientific work describes a test conducted in a multidisciplinary test box on the testing training ground of the Orenburg branch of the All-Russian Research Institute for Fire Protection of EMERCOM of Russia. For the experiment there was built a room to simulate a service station (or parking box) for two cars. The frame was made of wooden bars and a plastic film was used to isolate the internal volume. The experimental installation consisted of a gas source with an internal diameter of 5 mm, located in the center of the room, and a system for gas supply and registration of experimental data from six gas analyzers SGOES-2 with a measurement range of pre-explosive concentrations from 0 to 100% of the lower concentration limit of flame propagation (NKPR) or a volume fraction from 0 to 1.7% with absolute ± 5% NKPR (in the range from 0 to 50% NKPR) and relative ± 10% NKPR (in the range from 50 to 100% NKPR) errors. In the center of the experimental room there was placed a car with the gas source in the trunk. All openings to the interior were insulated with plastic film and mounting foam. Natural cracks were left between the trunk lid and the body. The gas source is located in the trunk of the car and is directed towards the wide part of the trunk at an angle of 30 degrees relative to the floor (simulating the location of the gas cylinder used in cars). The gas analyzers were located along the wall, where the outflow is directed along the perimeter of the trunk, and one gas analyzer was located directly in the trunk behind the gas analyzer to control gas contamination. Propane has been released into the trunk with a constant flow rate of 2.8 m/h for 5 minutes. There were 8 test starts of the gas supply system (the flow vertically down), and then there were carried out 3 experiments per 3 series of tests in each. The purpose of the test was to study the mechanism of spatial gas propagation in an confined space for validation of mathematical models used in the ANSYS Fluent software package when modeling the propane intake into the confined space

Assessment of the quality of the southern Bug waters within the Khmelnytsky region and biotechnological ways to solve their purification

Water resources are the national wealth of each state, an important natural resource, and determine the development opportunities of most sectors of the economic complex of Ukraine. The Southern Bug River is the largest river, the basin of which is completely located in Ukraine. Due to the intensive growth of anthropogenic impact on the studied reservoir and the economic use of its resources, the quality of water in it has significantly decreased. To improve the quality of water in rivers, it is optimal to use biotechnological methods, which provide many opportunities for effective solutions to issues related to monitoring, assessment, and treatment of polluted watercourses. The aim of our study was to assess water safety, the current ecological status of the Southern Bug River within the Khmelnytsky region in three areas (Maryanivske Reservoir, Kopystyn, Shchedrivske Reservoir) and use in domestic needs, with analysis of potential risks to human health, development of new biotechnological and improvement of existing measures to improve water supply. The experimental part of the work was performed on the basis of the Khmelnytsky Regional Department of Water Resources in the laboratory at the address Khmelnytsky, st. Soborna, 29. We conducted a chemical assessment of the Southern Bug River on three indicators: salt composition (I1), tropho-saprobiological (I2), and specific toxic substances (I3). Research of river waters was carried out in order to control the MPC (maximum permissible concentrations) of substances for use in household and food needs of the population and to propose biotechnological methods of river water purification within the Khmelnytsky region. According to our research on hydrochemical characteristics, the water contained elevated levels of NH4, NO2, NO3, PO4, the average values of HSC (chemical oxygen demand) exceeded the MPC in all areas by 2 to 5 times. This may be due to exposure to organic compounds of natural origin. The content of nitrites, nitrates is within normal limits, but the content of ammonium salt exceeds the MPC up to 20 times in the village Kopystyn and from 2 to 7 times in the village of Letychiv. According to many indicators of the salt block, the maximum concentration limit was not exceeded, except for the village Kopystyn, the concentration of Magnesium (Mg) was 84.33 mg/dm3 at a rate of 40.00 mg/dm3. According to specific toxic substances, the water belonged to the III class 4 quality category, Chromium (Cr) was not detected, Manganese (Mn) and Copper (Cu) were within normal limits, although the Copper content was high. The concentration of Iron (Fe) varies in different areas and during the year, there is a case of excess Iron in the village. Kopistin up to 0.86 mg/dm3 at a rate of 0.30 mg/dm3. Iron affects the intensity of phytoplankton development and the qualitative composition of the microflora, so its concentration is subject to seasonal fluctuations. To improve the quality of water in the Southern Bug River, we have proposed the use of biotechnological methods, including those that provide many opportunities to effectively address issues related to monitoring, assessment, and treatment of polluted watercourses.

Antioxidant Activity of Amino Acid Sodium and Potassium Salts in Vegetable Oils at Frying Temperatures

Previous studies reported that several amino acids had strong antioxidant activity in vegetable oils under frying conditions. In this study, the carboxylic acid group of amino acids was converted to a carboxylate group (-COO-Na+ or -COO-K+), a heating study was conducted with amino acid salts in soybean oil at 180 ºC. Sodium salts of amino acids including alanine, phenylalanine, and proline and disodium glutamate had significantly stronger antioxidant activity than the corresponding amino acids, and potassium salts had stronger antioxidant activity than sodium salts. Potassium salts of alanine and phenylalanine more effectively retained tocopherols in soybean oil than the corresponding amino acids during heating. Phenylalanine potassium salt had stronger antioxidant activity than phenylalanine in other vegetable oils including olive, high oleic soybean, canola, avocado, and corn oils. Phenylalanine potassium salt at 5.5. mM more effectively prevented oil oxidation than tert-butyl hydroquinone (TBHQ), a synthetic antioxidant, at its legal concentration limit (0.02%) indicating its feasibility as a new antioxidant for frying.

Assessment of radiation dose hazards caused by radon and its progenies in tap water by the human dosimetric model

Radon is readily soluble in water, and radon exposure caused by household water consumption may pose a threat to public health. In this study, the radon concentration in the tap water of residential buildings was measured, and the average value was 543.33 mBq L−1, which was in line with the radon concentration limit recommended by USEPA (11.11 Bq L−1) and EURATOM (100 Bq L−1), and also within the range of the results of radon concentration measurements in tap water in other countries or regions. Through water bath heating at different temperatures, the radon retention curves of multiple groups of samples at different temperatures were fitted and analyzed. The results showed that the radon retention continued to decrease between 25 and 70 °C, remained stable between 70 and 85 °C, and then continued to decline slowly. Combined with the measurement results, the effective doses of α- and β-particles emitted by 222Rn and its progenies to residents respiratory and alimentary tissues and organs were calculated using the computational model provided by ICRP under two typical water scenarios of shower and drinking water, and the results show that radon exposure caused by normal water consumption will not pose a serious threat to public health.

POSSIBLE CAUSE OF ABNORMAL COLLAPSE OF THE WORLD TRADE CENTER BULDING

Национальный институт стандартов и технологий (NIST) провел расследование о причинах обрушения Всемирного торгового центра (WTC). Однако до сих пор встречаются суждения о якобы специально подготовленном взрыве зданий WTC некими «заговорщиками». Действительно, для многих наблюдателей и экспертов картина обрушения башен WTC послужила поводом для сомнений - как могли высотные здания относительно ровно, практически вертикально, обрушиться? В связи с этим, в работе обсуждается гипотеза, на основе которой можно объяснить специфический характер обрушения зданий. Лифтовые шахты в зданиях занимали 25% площади на плане. Они были сгруппированы в центре здания. Внутренний объем шахт для лифтов на протяжении 200 метров по высоте равен 120000 м3. Разлившийся авиационный керосин пропитал поверхности стенок лифтовых шахт и создал внутри смесь из паров керосина и воздуха. У керосина в три раза ниже поверхностное натяжение, чем у воды. Поэтому он легко смачивает почти любые поверхности, быстро растекается и пропитывает всё. Для керосина концентрационные границы взрываемости в смеси с воздухом находятся от 0,8 до 5,2%. Энергия паров керосина в лифтовых шахтах, равная нижнему концентрационному пределу взрываемости, эквивалентна 13000 кг ТНТ. При случайной искре происходит объемный взрыв паров керосина в лифтовых шахтах. Энергии взрыва достаточно для разрушения и последующего почти вертикального обрушения здания. The National Institute of Standards and Technology (NIST) has conducted an investigation into the causes of the collapse of the World Trade Center (WTC). However, there are still opinions about the allegedly specially prepared explosion of the WTC buildings by some “conspirators”. For many observers and experts, the picture of the collapse of the WTC towers gave rise to doubts - how could high-rise buildings collapse relatively evenly, almost vertically? The paper discusses a hypothesis on the basis of which it is possible to explain the specific nature of the collapse of these buildings. The elevator shafts were grouped in the center of the building. They occupied 25% of the area on the plan. The internal volume of the elevator shafts over a length of 200 meters in height is equal to 120,000 m3. The spilled aviation kerosene soaked the surfaces of the walls of the elevator shafts and created a mixture of kerosene and air vapors inside. Kerosene has three times lower surface tension than water. Therefore, it easily wets almost any surface, spreads quickly and soaks everything. For kerosene, the concentration limits of explosiveness in a mixture with air are from 0.8 to 5.2%. The energy of kerosene vapors in lift shafts, equal to the lower concentration limit of explosiveness, is equivalent to 13000 kg of TNT. In case of an accidental spark, a volumetric explosion of kerosene vapors occurs in the elevator shafts. The energy of the explosion was enough to destroy the building causing subsequent almost vertical collapse.

SATURATION RESEARCH MAKSIMALNY BY WOOD-SHAVING PLATES OF PREMISES

The wood-shaving plates (DSTP) released by the domestic industry with use of carboamidoformaldehyde pitches (KFS) have very essential shortcoming connected with their toxicity because of considerable allocation from them gas, harmful to the person, - formaldehyde. In recent years formaldehyde is recognized as substance, cancerogenic for the person. It concerns different type of plates: from needle (DSTP) and large-size shaving (OSB), fiber boards (DVP), including medium-density DP-SP (or MDF). The Russian Ministry of Health has established very strict requirements on release of formaldehyde in air both in premises, and in free air the admissible level of which (DU and maximum-permissible concentration – maximum concentration limit) makes only 0,01 mg/m3 of air when testing materials by chamber method. The plate materials released now can exceed DU of 17 times stated above. Despite attempts of institute Vniidrev through appeals to relevant authorities of the Ministry of Health to increase such admissible level in our country, generally for plate materials, were not crowned with success yet and this level in real time remains in force. It is possible to use such plates in premises only at very small saturation room void volume plates (the saturation is defined as the relation of surface area of plates indoors to room void volume). In foreign practice of DU of formaldehyde in air much higher and makes 0,124 mg/m3 of air. Results of researches of the maximum saturation (the relation of surface area of plates to room volume) depending on class of emission of DSTP and DU formaldehyde at values 0,01 and 0,124 of mg/m3 of air in relation to premises are given in the real work.

Effects of Re on Vacancy Mobility in a Ni-Re System: An Atomistic Study

The performance of modern Ni-based superalloys depends critically on the kinetic transport of point defects around solutes such as rhenium. Here, we use atomistic calculations to study the diffusion of vacancy in the low-concentration limit, using the crystalline fcc-framework nickel as a model. On-the-fly kinetic Monte Carlo is combined with an efficient energy-valley search to find energies of saddle points, based on energetics from the embedded atom method. With this technique, we compute the local energy barriers to vacancy hopping, tracer diffusivities, and migration energies of the low-concentration limit of Ni-Re alloys. It was estimated that the computed diffusion rates are comparable to the reported rates. The presence of Re atoms affects the difference between the energy of the saddle point and the initial energy of point defect hopping. In pure Ni, this difference is about 1 eV, while at 9.66 mol% Re, the value is raised to about 1.5 eV. The vacancy migration energy of vacancy in the 9.66 mol % Re sample is raised above that of pure Ni. Our findings demonstrate that even in the low-concentration limit, Re solute atoms continue to play a crucial role in the mobility of the vacancies.