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.

Vertical Distribution of Phosphates in the Black Sea Based on the Expeditionary Data, 2016–2019

Purpose. The purpose of the study is to analyze the features of vertical distribution of phosphates and dissolved organic phosphorus (Porg) in the Black Sea at the present period. Methods and Results. The data obtained by the scientists of Marine Hydrophysical Institute in the Black Sea within the economic zone of Russia in 2016–2019 were used. At more than 200 deep-sea stations, a cassette of 12 bathometers (the Seabird-Electronics STD-instrument) was applied for taking hydrochemical samples at certain isopycnic surfaces, usually at σt = 16.30; 16.25; 16.20; 16.20; 16.15; 16.10; 16.05; 16.00; 15.95; 15.90; 15.80; 15.50, 14.0 kg/m3. At the coastal shallow-water stations, samples were taken at the 10 m intervals. Such a scheme permitted to carry out vertical sampling in the upper mixed layer and in the suboxic zone (including its upper boundary) with possible minimum of phosphates, to determine the depth of hydrogen sulfide formation and the location of the phosphates concentration maximum in the upper part of the anaerobic zone. Conclusions. From the surface to isopycn σt = 14.4 kg/m3, the content of phosphates and Porg does not exceed 0.1 µM; below this isopycnic surface, the phosphates concentration begins to increase, whereas of Porg remains at the same level. At all the profiles of the phosphates vertical distribution, the phosphates concentration minimum was recorded near the isopycnic surface σt = 15.8 kg/m3, and its maximum – near the isopycnic surface σt = 16.2 kg/m3. The minimum content of phosphates varied within 0–1.5 µM; in 2016–2017 the phosphates concentration maximum did not exceed 8 µM; in 2018, in many cases, it was higher than 12 µM, and once, near the Kerch Strait, it exceeded 17 µM. Increase in the magnitude of the maximum phosphates concentration (in the previous studies in 1988–2013, it did not exceed 8 µM) is assumed to be related to installation of the supports for constructing the Kerch Bridge.

Cadmium and zinc uptake by dried activated sludge: Equilibrium and experimental design study

Removal of Cd2+ and Zn2+ ions from single and binary solutions by dried activated sludge was studied in batch experiments. It was shown that the metal removal is a rapid process significantly influenced by solution pH. Maximum uptake of both Cd and Zn was reached at pH 6.0 and negligible uptake was observed at pH 2.0. The Langmuir isotherm was found to well represent the measured equilibrium sorption data in single metal systems and the maximum sorption capacities Qmax of the activated sludge (d.w.), calculated from Langmuir model were 540 ± 16 μmol/g for Zn2+ and 510 ± 17 μmol/g for Cd2+ ions. The Response surface methodology (RSM) was used for investigation of interaction and competitive effects in binary metal system. It was found that dried activated sludge in binary system Cd-Zn has slightly higher affinity for Cd2+ comparing with Zn2+ ions. Competitive effect of Cd on Zn uptake increased with increasing solution pH and Cd initial concentration. Maximum sorption capacities of the activated sludge were 321 μmol Cd2+/g and 312 μmol Zn2+/g. RSM appears to be a better tool for the evaluation of interaction and competitive effects in binary systems than both the simple extrapolation from single-component systems and experimentally difficult study of multi-component systems.

A GIS Based Methodology to Obtain the Hydrological Response to Storm Events of Small Coastal Basins, Prone to Flash Flooding

The present study aims to investigate the hydrological response of small coastal watersheds to storm events. Areas around the Mediterranean Sea are usually characterized by streams with intermittent flows and flash floods are common. Firstly, we analyze the geomorphological, soil and land cover characteristics of the watershed in order to estimate their effect on surface runoff. Furthermore, the rainfall characteristics of an extreme event that caused flash flooding in the past are analyzed. By combining these factors, we are able to predict the response of this basin to severe storm events. The study area is located in the island of Samos, in Eastern Greece, where flash flood events are usual and pose a risk to areas located around rivers. In this area runoff is intermittent, occurring mainly during storm events and there is a lack of discharge or other instrumental measurements. By applying the SCS-CN method we estimate the response of two of the largest watersheds in Samos Island, through the construction of a Synthetic Unit Hydrograph (SUH). Firstly, we examined the record of historic floods in the area, selecting a large flash flood event (November 2001) and then obtained the daily rainfall data, which are used by the SCS method for the calculations. We applied the SCS methodology in order to estimate various parameters (e.g. lag time, time of concentration, maximum discharge), which also required the calculation of the Curve Number (CN) for each watershed. During this event (136 mm rainfall), we calculated a direct runoff (excess rainfall) of 44%-48% for these watersheds. This methodology can be particularly useful in simulating the hydrological response of small Mediterranean watersheds and to introduce better strategies for the management of the whole drainage basin.

What caused the frequent and widespread occurrences of noctilucent clouds at middle latitudes in 2020?

The 2020 summer season has revealed frequent occurrences of noctilucent clouds (NLCs) around the Northern hemisphere at middle latitudes (45–55° N), with the lowest latitude at which NLCs were seen being 34.1° N. In order to investigate a reason for this NLC extraordinary summer season, we have analyzed long-term Aura/MLS satellite data for all available summer periods from 2005 to 2020. Both Aura/MLS summer temperature and water vapor in the upper mesosphere and the mesopause region, between 74 and 89 km altitude, have been considered. We have found that there has been a moderate decrease in the upper mesosphere temperature between 2016 and 2020 and no dramatic changes have been observed in temperature in the summer of 2020 at the middle latitude mesopause. At the same time, water vapor concentration has significantly increased (by about 12–15 %) in the zonal mean H2O value in the 2020 summer compared to 2017, meaning that the summer mesopause at middle latitudes has become more wet. At the same time, no increase in water vapor has been detected at the high latitude high altitude mesopause. A combination of lower mesopause temperature and water vapor concentration maximum at middle latitudes is the main reason for frequent and widespread occurrences of NLCs seen around the globe at middle latitudes in the summer of 2020. The 24th solar cycle minimum cannot explain the H2O maximum in 2020 since the correlation between Lyman-α flux and the amount of water vapor is low. The increase in volcanic activity from 2013 to 2015 (and its recent maximum occurred in 2015) explains the increased amount of water vapor in the upper mesosphere for the past years and its maximum in 2020 due to volcanic water vapor being injected into the atmosphere and transported into the upper mesosphere. The 5-year delay between volcanic activity and water vapor maximum is well explained by a general meridional-vertical atmospheric circulation.

Preparation of Natural Ouw Clay-Chitosan Composite and Its Application as Lead and Cadmium Metal Adsorbent

This study aims to obtain the optimum ratio of Ouw Natural Clay (LAO):Chitosan in the manufacture of chitosan-LAO composites. The composite will be used as an adsorbent for heavy metals Lead (Pb) and Cadmium (Cd). LAO-Chitosan composites were made with the ratio of LAO:Chitosan = 1.25:1, 2.5:1, 5:1. XRD and SEM were carried out for each composite. The performance as a Cd metal adsorbent was determined by calculating the adsorption capacity. Composites with a ratio of 1.25:1 have the best adsorption capacity. The performance as adsorbent for Cd metal was determined by calculating the absorbed Cd concentration. Maximum results are achieved by composites with a ratio of 5:1.

Assessment of process parameters in a dehumidification process using biomass-based wood shaving as a packing material

In the current study, the performance of the counterflow dehumidification test rig using wood shaving packing has been analysed. Wood shaving packing with the density 500 kg/m3 was used along with the CaCl2 desiccant with varying concentration. Mass flow rate of air was varied and the dehumidification performance parameters like moisture removal rate, dehumidification efficiency, coefficient of performance, change in relative humidity, change in the pressure and mass transfer coefficient were evaluated. Output parameters were compared with the commercially available cellulose packing with the wettability of 632 m2/m3. Results showed that, even though the performance of wood shaving packing is slightly less than the Celdek packing, performance of wood shaving is promising at 40% desiccant solution concentration. Maximum relative humidity difference, coefficient of performance and dehumidification efficiency obtained with wood shaving pad material were found to be 19%, 1.88 and 69.5%, respectively.

Seasonal variation in heavy metals of forest soils of Dehradun

The present study was carried out to characterise the load of heavy metal in the forest soils of Dehradun during various seasons. Surface (0-15 cm) and sub surface (15-30 cm) soil samples were collected from four different sites during summer, monsoon and winter seasons. The results revealed that the maximum Cadmium concentration was recorded in surface (0-15cm) soils and minimum in sub-surface soils (15-30cm). The Cd concentration maximum during summer followed by winter and monsoon. Similar pattern of distribution of chromium was recorded in surface soil. The Chromium content was observed in the order of winter>summer>monsoon in surface soil and summer>winter>monsoon in sub-surface soils. The concentration of Copper in surface soils varied from 3.19 to 0.52mgkg-1 while in sub-surface soil, it varied between 2.25 and 0.57 mg kg-1. The copper concentration was maximum during winter followed by summer and monsoon. The lead concentration was recoeded maximum at site-II and minimum at site-IV whereas, it was recorded maximum during winter and minimum during monsoon. In general, all the heavy metals were found to decrease with soil depth. The concentrations of heavy metal were quite low but their presence in sites makes them potential to increase toxicity in future owing to more environmental degradation.

Effective removal of fly ash by Penicillium chrysogenum and determination of direct fly ash toxicity with Daphnia magna

This study demonstrates the removal of fly ash with Penicillium chrysogenum, a newly isolated species of fungus, and acute toxicity assessment with Daphnia magna. In the study, two different removal mechanisms were compared, both bio-removal and bio-sorption. Six different ash and three different biomass concentrations were used simultaneously. Although other fungal species in the literature failed at such a high concentration of fly ash, P. chrysogenum was able to tolerate it even at 10% concentration. The highest bio-removal yield was recorded as 100% at 0.5% fly ash concentration. Maximum bio-sorption yield was 95.27% after 24th hour. The evaluation results of fly ash bio-toxicity by D. magna showed that the no observed effect level (NOEL) was 0.2 mg/L and the low observed effect level (LOEL) was 0.5 mg/L. The element analysis, determined by ED-XRF, clarified that Ca, Si, Fe and S were the common elements in this ash. This is the first study in the literature where fly ash removal was carried out using P. chrysogenum for both bio-removal and bio-sorption and needs to be developed in the future.

Influence of Ice Floe Shape and Distribution on Ship Resistance

Many ice basin tests have been performed on ships to assess the ice resistance of the hull in an ice floe field. During these tests, many parameters are studied, the most important of them being the transit speed, the thickness and the concentration of ice. Given the cost and the time required to carry out these basin test campaigns, it is imperative to keep the number of tests to the strict minimum, whilst still making it possible to draw conclusions about the sizing of the vessel. Hence, the influence of ice floe shape and their distribution in the field are generally not considered. A way to achieve sensitivity studies regarding these parameters is to use numerical simulations in addition to a basin test. There are few advanced numerical design tools available in the market, especially those able to cope with any kind of structure geometry and a large variety of ice interaction & failure mechanisms. In 2012 TechnipFMC, Cervval and Bureau Veritas initiated a common development program to offer a new tool for the design of offshore structures interacting with ice combining a variety of models and approaches such as analytical, numerical and empirical. This numerical tool called Ice-MAS (www.ice-mas.com) uses a multi-agent technology and has the possibility to combine, in a common framework, multiple phenomena from various natures and heterogeneous scales (i.e. drag, friction, ice-sheet bending failure, local crushing and rubble stack up). The study presented in this paper compares the simulation results for different ice floe fields not only in terms of concentration, maximum size of floe and their distribution but also in the way to generate the ice floe and its shape.