Уточнение температурных графиков тепловых сетей при централизованном теплоснабжении потребителей

Наголошено, що у зв’язку з підвищенням нормативної температури внутрішнього повітря житлових будівель до 20 ºС виникає необхідність уточнення температурних графіків теплових мереж при централізованому теплопостачанні споживачів. За відомими формулами отримані залежності зміни температур води в подавальній та поворотній лініях теплових мереж від температури зовнішнього повітря при р вн t =20 ºC для розрахункових температурних графіків 150/70; 130/70; 115/70; 105/70; 95/70 ºC для всіх обласних центрів України та деяких міст АР Крим. Показано, що зміна температури внутрішнього повітря до 20 ºC призводить до збільшення витрати мережної води від 4,7 % до 8,3 % порівняно з наявними графіками.It is emphasized that due to increasing of the regulatory temperature of indoor air of residential buildings up to 20 º C is necessary to clarify the temperature graphs of heating networks in district heating. By the known formulas relevance of water temperature changes in the water supply and rotary lines of heating system from the outside air temperature at t = 20 º C are obtained for the calculating of temperature graphs 150/70, 130/70, 115/70, 105/70, 95/70 º C for all regional Ukraine’s centers and some cities in Crimea. It is stated that the change of internal air temperature to 20 º C leads to increasing of water costs from 4,7% to 8,3% compared with the existing schedule.Отмечено, что в связи с повышением нормативной температуры внутреннего воздуха жилых зданий до 20 °С возникает необходимость уточнения температурных графиков тепловых сетей при централизованном теплоснабжении потребителей. По известным формулам были получены зависимости изменения температур воды в подающей и обратной линиях тепловых сетей от температуры наружного воздуха при р вн t =20 ºC для расчетных температурных графиков 150/70; 130/70; 115/70; 105/70; 95/70 ºC для всех областных центров Украины и некоторых городов АР Крым. Также показано, что изменение температуры внутреннего воздуха до 20 ºC приводит к повышению расхода сетевой воды от 4,7 % до 8,3 % по сравнению с существующими графиками

Impact of hydrotechnical construction on aquatic ecosystems of the Kiliia branch of the Danube Delta

Resumption of shipping in the Bystryi branch in the Ukrainian part of the Danube Delta, one of the largest aquatic-wetland areas of Europe and the world, has made it necessary to control the anthropogenic impact on the neighboring water areas of the Danube Biosphere Reserve. The objective of the study was comparing the compositions and structure of phytoplankton, microphytobenthos, macrophytes, benthic invertebrates and ichthyofauna of the mouth area of the Bystryi branch with such communities of the mouths of the branches Vostochnyi, Tsyhanka and Starostambulskyi, which are situated in the protected zone and characterized by limited anthropogenic activity. We also determined the correspondence of the descriptors of biotic groups to the categories of the ecological status according to the Water Framework Directive of the EU. The studies were performed in the autumn and summer periods in 2020–2021. We recorded 367 species of animals and plants, the richest biodiversity was seen for the biota of the Bystryi branch – 250 species, and 180–231 species of hydrobionts were found in the undisturbed mouths. We determined 25.3% of shared species for the water areas, and therefore high values of similarity of the species compositions according to Bray-Curtis (47.5% to 81.5%). We determined no significant differences between the groups of the mouths of the examined branches according to most indicators of taxonomic and ecological structure. As the descriptors of ecological status, we chose assemblage indices of phytoplankton and microphytobenthos, which are based on ratios of biomass of functional groups of algae, and also the Macrophyte Biological Index for Rivers, saprobic index of Zelinka & Marvan and Biological Monitoring Working Party Index of Benthic Invertebrates and Representation of Species of Ichthyfauna according to vulnerability to actions of environmental factors. We determined that the range of descriptors of phytoplankton and microphytobenthos corresponded to the “high” ecological status category, such of macrophytes and benthic invertebrates to “good”, and such of ichthyofauna varied “high” to “good”. In general, all the mouth areas were characterized by “good” ecological status. Similarities of the species composition and the structure of biotic communities of the mouths of the studied branches of the delta indicate the absence of negative impact of the deepwater shipping on adjacent ecosystems, which may be related to the peculiarities of reactions of groups in the water areas with natural stress, as well as local impact of the hydrotechnical construction

Biochemical markers of vital biodestruction in common oak (Quercus robur)

The wood of the common oak (Quercus robur L.) has high mechanical strength, elasticity and resistance to fracture. However, constitutional stability is not always able to provide the plants with reliable protection from wood-decay fungi, and the initial stages of biodegradation are difficult to determine. Therefore, this study concerns research on appropriate biochemical markers for early diagnostics of wood defects. The total content of phenolic compounds in leaves and wood was determined by a spectrophotometer Optizen Pop using Folin & Ciocalteu’s phenol reagent; the flavonoid content in leaves – by adding solutions of aluminum chloride and sodium acetate to methanolic extracts; catechins content – by the reaction with vanillin reagent; the concentration of phenolic antioxidants – by Brand Williams; chlorophyll and carotenoids’ contents in leaves – by the formula for methanol extracts; the qualitative composition of phenolic compounds – by high performance liquid chromatography and highly effective thin-layer chromatography. During the planned felling of oak trees on the territory of the Boyar Forest Research Station, trees were found with signs of brown streak and biodestruction of wood. Brown streak in wood is caused by a polycondensation of phenolic compounds, which are deposited on the internal surfaces of tracheal elements. In cases of an increase in the total amount of oxidized polyphenols, the cell walls are also stained. Active oxidation processes in wood have a systemic nature for the plants and affect the physiological state of the assimilation apparatus. We determined that in leaves of the trees with signs of brown streak the total phenol content increases in comparison with the control by 1.6 times, as well as flavonoid and catechin content. Our research has shown that the complex of plastid pigments in common oak leaves does not significantly change in the early stages of destructive processes. Increase of brown streak and appearance of rot in wood are associated with slight increase in chlorophyll a to b ratio in leaves. Chromatographic profiling of the leaves showed that the presence of brown streak changes the content of individual phenolic compounds. The trees with brown rot have more substances with UV spectrum characteristic for kaempferol glycosides compared to the control. The results have shown that the biochemical profiles of the trees with signs of brown streak and brown rot differ from the control by the composition of low and medium polar compounds. The absence or presence of some individual phenolic components and their ratio in the leaves are considered as biochemical markers of hidden wood defects

Method of gas flows calculation in solid propellant rocket engines taking into account the combustion of solid fuel charge

The paper presents a method for calculating the local and integral characteristics of the flow in the axisymmetric gas-dynamic paths of solid propellant rocket motors, taking into account the combustion of a charge of solid fuel. The numerical method of calculation is based on the use of the Godunov scheme, formulated for moving computational grids. The speed of movement of the combustion surface is defined locally on the edge of each calculation boundary cell. This approach allows us to take into account the uneven distribution of the pressure of the combustion products in the free volume of the combustion chamber. In test calculations, the power law of burning rate is used. Calculations of the gas flow in the solid propellant combustion chamber with cylindrical charge of solid fuel are carried out. Unsteady pressure curve in the combustion chamber is obtained. The method allows to determine all integral characteristics of the developed solid propellant rocket motors as a function of the engine running tim

Projectile fragmentation at Fermi energies with transport simulations

Projectile fragmentation at Fermi energies is an important method to produce radioactive beams for the study of isospin asymmetric nuclear matter. Fragmentation is usually parametrized successfully by empirical phase space models. In this contribution we apply a microscopical method, semiclassical transport theory, to study in detail the reaction mechanism of the fragmentation process. We apply it to experimental data of 18O on 181Ta at E/A = 35 MeV measured in Dubna. We calculate consistently the excitation energy of the primary fragments and take into account their decay by a statistical model. It is found that the dissipative part of the fragment spectra is well described by transport theory. However, there are in addition important direct and collective contributions

LUMBAR DRAINAGE IN CHIASMOSELLAR TUMORS

Lumbar drainage is one of the methods used to prevent the occurrence of intracranial hypertension and treatment of nasal liquorrhea in patients after by endonasal transsphenoidal endoscopic removal of tumors of the chiasmosellar region. The application of this method intraoperatively is a standard procedure to facilitate manipulation of the brain surgeon, but prolonged post-operative drainage is used extremely selectively and depending on the approaches taken in the specific medical organization. The present paper describes different frequency and risks of lumbar drainage after the surgery. Our aim was to assess the efficacy and safety of postoperative drainage of liquor from the surveyed patients. We observed 80 patients in the postoperative period who were conducted passive lumbar drainage. The assessment was performed of the cell count and discharge of the liquor, depending on the size of the tumor. During the study, it was found that the optimal timing of drainage is: 3 days for patients with small and medium-sized pituitary adenomas and 5 days for patients with large and giant adenomas. In all cases, the maximum values of cell count were observed on the first day and they gradually reduced by the 3-5th days due to reorganization of the liquor and reduced inflammatory response. Postoperative meningitis developed in 6 (5.8 %) cases and in 3 cases this complication led to death. It has been found, that prolonged liquor drainage meets the standards of safety and effectiveness for the correction of intracranial hypertension and accelerates the rehabilitation of the CSF

Высокоэффективные системы вентиляции и кондиционирования воздуха общественных и промышленных зданий

Наведена методика порівняння за зведеними витратами п’яти найбільш відомих постачальників на ринок України припливно-витяжних камер місцевих систем механічної вентиляції та місцевих автономних систем кондиціювання повітря (спліт-систем). Отримано графіки залежності зведених витрат від повітропродуктивності (для припливних камер) та холодопродуктивності (для спліт-систем кондиціювання повітря).It is shown the method of comparing the reduced costs of five most popular suppliers in the Ukraine’s market local air-supply systems (jet chambers) and local air conditioning systems (split-systems). We obtain the graphs of depending reduced costs from air performance (for jet chambers) and chill performance – for split-systems.Приведена методика сравнения по приведенным затратам пяти наиболее известных поставщиков на рынок Украины приточно-вытяжных камер местных систем механической вентиляции и местных автономных систем кондиционирования воздуха (сплит-систем). Получены графики зависимости приведенных затрат от воздухопроизводительности (для приточных камер) и холодопроизводительности (для сплит-систем кондиционирования воздуха)