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.

Partial visual loss disrupts the relationship between judged room size and sound source distance

Visual spatial information plays an important role in calibrating auditory space. Blindness results in deficits in a number of auditory abilities, which have been explained in terms of the hypothesis that visual information is needed to calibrate audition. When judging the size of a novel room when only auditory cues are available, normally sighted participants may use the location of the farthest sound source to infer the nearest possible distance of the far wall. However, for people with partial visual loss (distinct from blindness in that some vision is present), such a strategy may not be reliable if vision is needed to calibrate auditory cues for distance. In the current study, participants were presented with sounds at different distances (ranging from 1.2 to 13.8 m) in a simulated reverberant (T60 = 700 ms) or anechoic room. Farthest distance judgments and room size judgments (volume and area) were obtained from blindfolded participants (18 normally sighted, 38 partially sighted) for speech, music, and noise stimuli. With sighted participants, the judged room volume and farthest sound source distance estimates were positively correlated (p < 0.05) for all conditions. Participants with visual losses showed no significant correlations for any of the conditions tested. A similar pattern of results was observed for the correlations between farthest distance and room floor area estimates. Results demonstrate that partial visual loss disrupts the relationship between judged room size and sound source distance that is shown by sighted participants.

Impact sound pressure values - Field measurements for different configurations of concrete slabs on the ground

The presentation will summarize and discuss values of field measured normalized impact sound pressure level L'n,w measured sideways with different configurations of concrete slabs on ground within buildings. All results are adjusted to receiving room volume of 100 m3 and with thickness of concrete slab 80-100 mm. Measurement on continuous concrete slab on expanded polystyrene gives L'n,w between adjoining rooms of 74 dB. Different principles of splitting have been investigated to evaluate the effect on L'n,w. The configuration where only the concrete slab is split (and with a plastic film between the concrete base and the upper layer of expanded polystyrene), gives L'n,w of approximately 66 dB which is 8 dB lower than for a continuous bare concrete slab. When both the concrete slab and the upper layer of expanded polystyrene are split, measurements show L'n,w of 58-61 dB for the case of no flooring, which is 13-16 dB lower than for a continuous concrete slab (no split). When both concrete slab and all layers of polystyrene are split down to continuous foundation measurements show L'n,w of 55 dB. The situation with concrete slab and all layers of polystyrene split and with no foundation beneath gives L'n,w of 46 dB. Consequences for airborne sound and R'w will be discussed as well for the above mentioned configurations.

Low ozone concentration and negative ions for rapid SARS-CoV-2 inactivation

Ozone is a powerful anti-bacterial, anti-fungal and anti-viral agent, yet exposure to high levels of ozone can pose risks to human/animal health and, in the long term, corrode certain objects. In order to overcome these risks, we evaluated the potential of using a relatively short exposure of a low concentration of ozone to disinfect an indoor environment in the absence of individuals and animals. ICON3 by O3ZONO/M2L, a new disinfection device generating both ozone and negative ions, was selected to assess the potential of this strategy to inactivate different viral isolates of SARS-CoV-2.Tests under controlled laboratory conditions were performed in a system consisting of an ozone-proof airtight plastic box inside a biological safety cabinet, where suspensions of two strains of SARS-CoV-2 were exposed to ozone and negative ions and virucidal activity was measured by means of two complementary methodologies: viral replication capacity and viral titer determination.These studies revealed that low concentration ozone (average 3.18 ppm after the peak) inactivated up to >99% of SARS-CoV-2 within 20 minutes of exposure. Under controlled conditions, similar ozone exposure was recreated with ICON3 in different volume rooms (15, 30, 60 m3) where a linear relationship was observed between the room volume and the time of continuous ozone/ions flow required to reach and maintain the desired ozone levels used in the laboratory studies.These studies suggest that ICON3 may have the potential for use in the disinfection of SARS-CoV-2 in indoor environments in the absence of individuals and animals, under properly controlled and monitored safety conditions.

Insights Gained from an Approximate Analytical Solution of the Evaporation Model Used by ConsExpo Web

Evaporation of chemicals is an important source of inhalative exposure. We analyzed here the ConsExpo evaporation model, which is characterized by a set of nonlinear differential equations only solvable by numerical means. It shows qualitatively different behavior for different parameters, but the exact conditions remain unclear. This article presents an approximate analytical solution of the ConsExpo evaporation model, derived by using a specific linearization of the nonlinear equations valid for small concentrations. From this solution, three different boundary cases or regimes are found: quick release, near equilibrium, and ventilation driven regime. Depending on the evaporation regime, different parameters influence peak substance air concentration: Quick release regime: total substance amount and room volume; near equilibrium regime: vapor pressure, substance concentration in the product, and molecular weight of the product matrix; ventilation driven regime: vapor pressure, substance concentration in the product, room volume, surface area, mass transfer coefficient, ventilation rate, and molecular weight of the product matrix. A graphical method is developed to display the position of a given scenario in relation to the three regimes. Thus, the approximate analytical solution allows for a given situation to prioritize research for reducing uncertainty of the most sensitive parameters and helps to identify promising risk management measures.

Search for Available Biomechanical Technologies Suitable for Use in Physical Education Classes

Introduction: One of the most important physical education tasks in school is to learn motor actions. Biomechanical technologies can promote to this process. A school lesson is different from a sports training, so it is necessary keep in mind its specifics. The purpose of the article is to analyse the existing professional biomechanical complexes for their suitability for use in physical education classes. Methods: We studied articles on sports biomechanics and selected 20 professional biomechanical complexes. These complexes can be divided into four technological groups: Optoelectronic Measurement Systems (OMSs), Electromagnetic Measurement Systems (EMSs), Image Processing Systems (IMSs), Inertial Sensory Systems (IMUs). Besides that, we identified 10 crucial categories to estimate opportunity to use biomechanical complexes in school lessons: cost, complexity of setting up and using, assistance need, portability, universality, room volume, construction traumatic, place for using, promptness, volume of data. Thus, each complex was evaluated according to 10 criteria. The biomechanical complex was excluded from further consideration if it got a critical limitation at least one of the criteria. Results: None of the professional biomechanical complexes can be considered suitable for use in physical education classes. As alternative we propose using free biomechanical software and smartphone camera with slow-motion caption.

Quantification of the health-improving action of phyto modules in the rooms of child care preschool facilities

The effect of three phyto modules – different combinations of indoor plants with the pronounced phytoncide activity – on the qualitative and quantitative composition of microflora in the air and on a decrease in the risk of acute respiratory diseases (ARD) in children was studied during autumn and winter in 2018-2020 in child care preschool institutions. Sanitary descriptive, epidemiological, sanitary bacteriological and statistical methods were involved. Observation revealed higher attendance rate in the observation group, in combination with lower recorded incidence of disease in comparison with the reference group. The fraction of facultative microflora (FM) with respect to the total microbial count (TMC) was about 30 % in the rooms equipped with phyto modules, while the ratio was 60% in the rooms without plants. The degree of antimicrobial activity depended on the assortment of plants and on the total leaf area per unit room volume. The phytoncide effect of the plants was traced to the most remote point of the room under investigation – 3 m. A favorable factor was an increase in the relative air humidity from 26 to 40%.

Quantification of a Viromed Klinik Akut V 500 disinfection device to reduce the indirect risk of SARS-CoV-2 infection by aerosol particles

Indoor SARS-CoV-2 infections by droplets and aerosols are currently considered to be particularly significant. FFP2/3 respirator masks, which fit tightly and gap free, generally provide very good protection. In public transport, while shopping or in waiting rooms, they are therefore ideally suited to protect against direct and indirect infection. Unfortunately, these masks make it difficult to breathe and can be uncomfortable to wear in the long run. Therefore, these masks should be worn for a maximum of 3 × 75 minutes per day. These masks are therefore hardly suitable for schools or at work. The question therefore arises as to how people in closed rooms can be permanently protected from a SARS-CoV-2 infection. Large safety distances provide both self protection and protection of third parties, but they do not protect against indirect infection if the virus load in the room is high. Mouth and nose covers only offer protection of others against direct infection, but they do not protect the user against indirect infection. The same applies to faceshields and small protective walls. Indirect infections can be effectively prevented by free ventilation with windows or air conditioning systems that supply 100% outside air into the room, provided the air exchange rate is at minimum six times the room volume per hour. However, free ventilation by means of windows is rarely efficient enough, and in winter at the latest, it is no longer possible to open windows without wasting massive amounts of energy and endangering the health and well-being of people. The operation of air conditioning systems is also very energy-intensive during the cold season. Furthermore, most buildings do not have air conditioning systems. The question is therefore, how a largely safe protection against an indirect SARS-CoV-2 infection can be realized in closed rooms without wasting thermal energy and thus valuable resources. Technically, the problem can be solved with mobile disinfection devices or room air cleaners that separate the dangerous aerosol particles or inactivate the viruses by UV radiation or by contact with charge carriers. The potential of these devices is great and, since many German manufacturers produce these devices, they are also available. However, many of the devices offered do not provide effective protection because the volume flow is too small, the separation efficiency of the filters is too low and the performance of the UV and ionization unit is too weak. The Viromed Klinik Akut V 500 disinfection unit appears to meet the performance requirements and therefore the device is analyzed and evaluated in this study for its suitability to protect against SARS-CoV-2 infection.

On a composition of combustion products at a burning of methane-fluorinated hydrocarbon mixtures in air

Выполнена расчетная оценка равновесного состава продуктов горения околостехиометрических смесей вида метан - фторированный углеводород - воздух с использованием как программного комплекса Chemical Workbench, так и предложенной в настоящей работе упрощенной методики. Найдено, что основными продуктами горения являются CO, HO, CO, HF. При этом концентрации прочих продуктов горения имеют существенно более низкие значения. С помощью программного комплекса FDS выполнен расчет динамики концентраций опасных продуктов (СО, HF) в атмосфере модельного помещения объемом 12,6 м. Найдено, что для указанного помещения предельно допустимая концентрация CO достигается через 730 с после начала горения, а HF - практически мгновенно. Результаты работы могут быть полезны при применении фторированных углеводородов для пожаротушения и флегматизации горючих газовых смесей. Calculations of equilibrium compositions of combustion products at burning of near stoichiometric mixtures of methane-fluorinated hydrocarbon-air are presented. The program tool Chemical Workbench was used. Also a Simplified method was proposed. It was found that CO, HO, CO and HF are the main combustion products, and the concentration of other products are much more lower. The results of the calculations of the concentrations of the above mentioned products (CO, HO, CO and HF) by means of the simplified method are close to that obtained by the tool Chemical Workbench ones. The concentrations of CO and HF (the main hazardous products) as a function of time were determined for a typical room volume of 12, 6 m using the program tool FDS 6. It was found that a limiting allowable concentration of CO was reached after 730 s from the burning beginning, but at the case of HF this concentration was reached almost instantaneously. The results of this study can be used at an application of the fluorinated hydrocarbons for fire extinguishing and inertization of flammable gaseous mixtures.