Investigation of the field of colored dissolved organic matter concentration and its relationship to the salinity field in Dnieper-Bug estuary

Based on the data of the expedition carried out in August 2012, the features of the structure of the salinity and fDOM concentration fields, as well as the correlation between these values ​​in the Dnieper-Bug estuary, are analyzed. It is shown that the salinity field in the Dnieper-Bug estuary is characterized by all structural features typical of coastal sea areas freshened by river runoff, while the fDOM concentration field has anomalous properties due to the presence of an anthropogenic component of this value. The presence of fDOM of anthropogenic origin is most significant in the western part of the Dnieper estuary and is related to the influence of the city and port of Ochakov. The maximum content of fDOM was recorded here, which caused an anomalous horizontal distribution of this substance concentration, increasing from the mouth of the Dnieper to the open Black Sea waters. The contaminated areas of the studied water areas, which are adjacent to settlements and occupy the predominant part of the water surface of the Dnieper-Bug estuary, are characterized by an increased fDOM content and intrusive feature of the vertical structure of this substance concentration field of. It is revealed that in the Dnieper-Bug estuary there is no inverse correlation between the salinity fields and fDOM concentration, which is typical for unpolluted coastal waters, freshened by river runoff. A similar anomaly is an indicator of the pollution of coastal waters with organic matter.

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.

Impact of green initial cuttings of vegetative-active grafting points of cherry on rooting and its period, rods, and growth controlling plant substance concentration

This scientific paper presents the results of experiments on the propagation of vegetatively propagated clone grafts of cherries from green cuttings. In the experiment, the effect of the concentration of indolymic acid (IMK), the time of preparation of green cuttings and the part of the stem from which the green cuttings were obtained, on the growth of vegetatively propagated stems of cherries from green cuttings was studied. The object of study was the weakly growing vegetatively propagated VSL-2 (Krimsky-5) and CAB-6P grafts of cherries. The cuttings were treated with water concentrations of 20, 40, 60, 80, 100 mg/l to determine the optimal concentration of the growth regulating agent - IMK. Rapid acceleration of rhizogenesis processes and high root yield (78-81%) in green cuttings of cherry clone grafts were noted in the variant treated with IMK 80 mg/l water concentration. The rapid and early regeneration processes in green cuttings using the optimal concentration of IMK ensured that their conditional body diameter reached a standard (6-7 mm) size by the time of cutting grafts. In this experimental variant, the amount of plants that can be grafted has reached about 89% of the total number of plants that have taken root.

DETERMINATION OF OPTIMAL MODES FOR MEASURING THE SIZE OF COLLOIDAL PARTICLES BY PHOTON-CORRELATION SPECTROSCOPY AND ACOUSTIC SPECTROSCOPY

В данной работе представлены результаты измерения размера коллоидных частиц SiO двумя методами - фотонно-корреляционной спектроскопией динамического рассеяния света и акустической спектроскопией. Математическая обработка экспериментальных данных с помощью программного обеспечения спектрометров «Photocor-Complex» и «DT-1202» позволила получить гистограммы распределения по размерам коллоидных частиц диоксида кремния в стандартном образце. Впервые установлено, что оптимальными параметрами для измерения размера коллоидных частиц SiO методом фотонно-корреляционной спектроскопии являются концентрация вещества менее 1 %, угол положения фотодетектора 90° и количество измерений в цикле 50 - 100, а акустической спектроскопии - концентрация 1 %. This paper presents the results of measuring the size of colloidal SiO particles by two methods - photon-correlation spectroscopy of dynamic light scattering and acoustic spectroscopy. Mathematical processing of experimental data using the software of the Photocor-Complex and DT-1202 spectrometers made it possible to obtain of the size distribution histograms for silicon dioxide colloidal particles in a standard sample. For the first time it has been established that the optimal parameters for measuring the size of colloidal SiO particles by the photon-correlation spectroscopy are the substance concentration less than 1 %, the photodetector position angle of 90 degrees and the number of measurements in a cycle of 100 -150, and for the acoustic spectroscopy - 1 % substance concentration.