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Tytuł:
Desulfurization of Crude Oil by Laboratory Developed Multipumping Flow Injection Analysis System with Optimization by Response Surface Methodology
Autorzy:
Hadi, Ahmed Abdulrazzaq
Ali, Ali Abdulkhabeer
Khathi, Mohammed Turki
Powiązania:
https://bibliotekanauki.pl/articles/2202370.pdf
Data publikacji:
2023
Wydawca:
Polskie Towarzystwo Inżynierii Ekologicznej
Tematy:
multi-pumping flow system
desulfurisation
response surface
optimal conditions
Opis:
Sour crude oil is the crude oil that contains a high level of sulfur impurity. It can be toxic and corrosive. Before this lower-quality crude can be processed into other crude oil derivatives, the sulfur content must be reduced, raising the processing cost. A homemade semi-automated multipumping flow analysis system was constructed, consisting of several parts available on the local markets and at low economic costs to decrease the sulfur content of crude oil samples collected. The central composite design (CCD) and response surface methodology (RSM) have been used for modeling and optimization. The effects of the operational parameters, including polar and nonpolar solvent types, solvent flow rates (10–40 ml/min), mixing coil lengths (120–200 min), temperature (30–60 °C), and solvent entry time to the system (0–60 sec) were studied. Experimental and theoretical applications were made to determine the optimal sulfur content, which came out to be 1.438 and 1.395 wt.%, respectively. This system evaluated the effectiveness of the sulfur removal content for actual heavy crude oil by experimentally and theoretically to be 65.73 and 66.75% respectively. The semi-automated system was applied successfully to reduce the sulfur content in a highly sensitive and accurate way.
Źródło:
Journal of Ecological Engineering; 2023, 24, 2; 328--339
2299-8993
Pojawia się w:
Journal of Ecological Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Effect of grinding conditions of gears made of 20MnCr5 steel after single-piece flow heat treatment on the condition of the surface layer of the tooth working surface
Autorzy:
Stachurski, W.
Janica, J.
Januszewicz, B.
Pawłowski, W.
Sawicki, J.
Powiązania:
https://bibliotekanauki.pl/articles/24200636.pdf
Data publikacji:
2023
Wydawca:
Stowarzyszenie Komputerowej Nauki o Materiałach i Inżynierii Powierzchni w Gliwicach
Tematy:
thermo-chemical treatment
vacuum carburizing
single-piece flow method
gear grinding
technological surface layer
obróbka cieplno-chemiczna
nawęglanie próżniowe
jednoczęściowa metoda przepływowa
szlifowanie kół zębatych
technologiczna warstwa wierzchnia
Opis:
Purpose: The paper investigated the effect of selected processing conditions during gear grinding on the value and distribution of microhardness and residual stress formed in the technological surface layer of gears after thermochemical treatment (TCT) conducted by a continuous single-piece flow method. Design/methodology/approach: The gears were carburised with LPC at 920°C, then quenched in a 4D Quenching chamber at 7 bar and tempered at 190ºC for 3 hours. In the next step, the working surfaces of the gear teeth were ground by supplying grinding fluid (GF) to the grinding zone using the WET method and the MQL method with a minimum amount. Measurements were made on the distribution of microhardness and residual stress formed in the technological surface layer of gears after thermochemical treatment and after the grinding process. Findings: The results of the study showed the influence of workpiece speed vw and the method of delivery to the grinding zone GF on selected parameters describing the condition of the technological surface layer of the teeth of gears made of 20MnCr5 steel. The grinding process with a white aluminium oxide grinding wheel causes deterioration in the material's residual stress state. For each of the three analysed workpiece speeds vw, smaller changes in microhardness with respect to the microhardness of the material before grinding occur in the surface layer of samples ground with GF fed with the MQL method. Similarly, residual stress values are in the area of favourable compressive stresses. Research limitations/implications: Environmental considerations and the need to comply with increasingly stringent environmental protection and worker safety regulations are pushing researchers and entrepreneurs to completely eliminate or reduce the consumption of grinding fluids in the grinding process. Based on the research and analysis carried out in this study, it was concluded that applying minimum GF by the MQL method could be an alternative to the conventional WET method.Practical implications: In sustainable manufacturing, it is extremely important to produce high-quality items while reducing the cost of manufacturing and taking care of the environment and workers' health. This includes the manufacture of gears, a basic component used in gear transmissions in the automotive industry, for example. The research has established that it is possible to use the MQL method, which reduces the amount of GF used when grinding the working surfaces of gear teeth, as an alternative to the conventional WET method. Originality/value: The conducted research was the first to determine the most favourable conditions, in terms of the obtained residual stresses and microhardness, for grinding the working surface of gear teeth using the MQL method.
Źródło:
Archives of Materials Science and Engineering; 2023, 120, 2; 60--69
1897-2764
Pojawia się w:
Archives of Materials Science and Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Forecasting the Flow Coefficient of the River Basin Using Adaptive Fuzzy Inference System and Fuzzy SMRGT Method
Autorzy:
Gunal, Ayse Yeter
Mehdi, Ruya
Powiązania:
https://bibliotekanauki.pl/articles/27323840.pdf
Data publikacji:
2023
Wydawca:
Polskie Towarzystwo Inżynierii Ekologicznej
Tematy:
ANFIS
adaptive neuro-fuzzy inference system
SMRGT
flow coefficient
fuzzy logic
surface water
Opis:
In hydrology and water resources engineering, predicting the flow coefficient is a crucial task that helps estimate the precipitation resulting in a surface flow. Accurate flow coefficient prediction is essential for efficient water management, flood control strategy development, and water resource planning. This investigation calculated the flow coefficient using models based on Simple Membership functions and fuzzy Rules Generation Technique (SMRGT) and an Adaptive Neuro-Fuzzy Inference System (ANFIS) model. The fuzzy logic methods are used to model the intricate connections between the inputs and the output. Statistical parameters such as the coefficient of determination (R2), the root mean square error (RMSE), the mean absolute error (MAE), and the mean absolute percentage error (MAPE) were used to evaluate the performance of models. The statistical tests outcome for the SMRGT model was (RMSE:0.056, MAE:1.92, MAPE:6.88, R2:0.996), and for the ANFIS was (RMSE:0.96, MAE:2.703, MAPE:19.97, R2:0.8038). According to the findings, the SMRGT, a physics-based model, exhibited superior accuracy and reliability in predicting the flow coefficient compared to ANFIS. This is attributed to the SMRGT’s ability to integrate expert knowledge and domain-specific information, rendering it a viable solution for diverse issues.
Źródło:
Journal of Ecological Engineering; 2023, 24, 7; 96--107
2299-8993
Pojawia się w:
Journal of Ecological Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Anthropometric Variables and PEFR
Autorzy:
Chandel, Rashmi
Shivhare, Garima
Bhagat, Anumeha
Powiązania:
https://bibliotekanauki.pl/articles/2148829.pdf
Data publikacji:
2022
Wydawca:
Uniwersytet Szczeciński. Wydawnictwo Naukowe Uniwersytetu Szczecińskiego
Tematy:
anthropometric variables
body surface area
peak expiratory flow rate (PEFR)
peak flow meter
smoking
Opis:
Peak expiratory flow rate (PEFR) varies with anthropometric variables like calendar age, body height, body weight, and body surface area in different regions. The present study aims at analyzing the relationship of PEFR with anthropometric variables to know a reference value in this region. We conducted the present study on healthy adult males aged eighteen to forty-five years engaged in works where they were un-exposed to pollutants in Patiala, India. Subgroups were made in each anthropometric variable category. PEFR recording was done using Mini Wright Peak Flow Meter. Results are expressed as mean PEFR ± standard deviation (mean ± S.D.), while the students' t-test was used to determine the differences between the means. We observed a linear increase in PEFR with all anthropometric variables. The correlation of PEFR with anthropometric variables was determined. PEFR is positively correlated with body height and body surface area (r =+0.20) and negatively correlated with calendar age (r = - 0.24) and body weight (r = - 0.02). We conclude that PEFR correlates best with body height (r = +0.48), and the result is highly significant (p < 0.01).
Źródło:
Central European Journal of Sport Sciences and Medicine; 2022, 39; 75-80
2300-9705
2353-2807
Pojawia się w:
Central European Journal of Sport Sciences and Medicine
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Rational Liquid Cooling Systems of Internal Combustion Engines
Autorzy:
Moshentsev, Yuryi
Gogorenko, Oleksiy
Dvirna, Olha
Powiązania:
https://bibliotekanauki.pl/articles/2022422.pdf
Data publikacji:
2022
Wydawca:
Stowarzyszenie Inżynierów i Techników Mechaników Polskich
Tematy:
charge air cooler
cooling systems
heat transfer surface
Internal combustion engines
oil coolers
low-flow system
Opis:
The scheme of the cooling system is considered, which can be the basis for creating the most efficient cooling systems for IC engines of any purpose. It is assumed that the use of any other scheme is devoid of a rational basis. The scheme consists of two connected circulation circuits, in one of which the coolant flow rate is an order of magnitude less than in the second. The engine is included in a circuit with increased coolant flow. All heat exchangers are in the second circuit. Rules for the formation of such systems are formulated. The basis of the method for calculating such systems is considered. It is indicated that the flow rate through each heat exchanger must be determined by calculation to ensure the maximum efficiency of the cooling system. The considered scheme allows to provide the maximum possible depth of charge air cooling, if its temperature is not specified, or to ensure the minimum cost and compactness of the cooling system, if this temperature is known. The scheme allows regulating the temperatures of the cooling fluids of the system with all kinds of changes in the engine operating conditions and the ambient temperature.
Źródło:
Advances in Science and Technology. Research Journal; 2022, 16, 1; 158-169
2299-8624
Pojawia się w:
Advances in Science and Technology. Research Journal
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Study on the Effect of in Situ Surface Treatments of Medical Microfluidic Systems Obtained Through Additive Manufacturing
Autorzy:
Csapai, Alexandra
Țoc, Dan-Alexandru
Pașcalău, Violeta
Toșa, Victor
Opruța, Dan
Popa, Florin
Popa, Catalin
Powiązania:
https://bibliotekanauki.pl/articles/2134105.pdf
Data publikacji:
2022
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
additive manufacturing
microfluidic systems
surface roughness
biofilm growth
laminar flow
Opis:
This paper presents a comparative study on the effects of the in-situ surface modifications performed on “H” type microfluidic systems obtained via additive manufacturing. The microsystem was printed using a polylactic acid filament on an Ender-5 Pro printer. The surface modification of the main channel was done using chloroform by two different methods: vapor smoothing and flushing. The obtained surface roughness was studied using an optical microscope and the ImageJ software, as well as scanning electron microscopy. The effect of the channel surface treatment upon the characteristics of the fluid flow was assessed. The microfluidic systems were used for the dynamic study of biofilm growth of Candida albicans (ATCC 10231). The influence of the surface roughness of the main channel on the formation and growth of the biofilm was studied using quantitative methods, scanning electron microscopy imaging as well as optical coherence tomography.
Źródło:
Archives of Metallurgy and Materials; 2022, 67, 3; 1071--1078
1733-3490
Pojawia się w:
Archives of Metallurgy and Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The influence of workpiece speed on microhardness and residual stresses in vacuum-carburised 20MnCr5 steel using the single-piece flow method
Autorzy:
Sawicki, J.
Januszewicz, B.
Sikora, M.
Witkowski, B.
Powiązania:
https://bibliotekanauki.pl/articles/24200559.pdf
Data publikacji:
2022
Wydawca:
Stowarzyszenie Komputerowej Nauki o Materiałach i Inżynierii Powierzchni w Gliwicach
Tematy:
surface grinding
microhardness
residual stress
vacuum carburising
single-piece flow
szlifowanie powierzchni
mikrotwardość
naprężenie szczątkowe
nawęglanie próżniowe
przepływ jednoczęściowy
Opis:
Purpose: To determine the impact of selected conditions of abrasive treatment on the value and distribution of microhardness and residual stresses in layers carburised by a continuous single-piece flow method. Design/methodology/approach: Reference pieces were low pressure carburised at 920°C and then heat-treated in a 4D Quench heat treatment chamber at a pressure of 7 bar and tempered at 190ºC for 3 hours. In the next stage, samples were ground at various vw piece speeds, introducing grinding fluid into the cutting zone using the WET spraying method or using the MQL method at a minimum flow rate. The distribution of microhardness and residual stresses generated in the technological outer layer of the pieces following heat and chemical treatment and the grinding process was measured. Findings: Results of the tests indicated that the vw piece speed and method used to supply cooling and lubricating fluid to the grinding zone had an impact on selected parameters of the technological outer layer of flat samples made of 20MnCr5 steel. The process of grinding using an electrocorundum grinding wheel results in a deterioration of residual stresses in the material. For each of the three analysed vw piece speeds, reduced changes in material microhardness prior to cutting occur in the outer layer of samples ground using GF supplied at a minimum flow rate using the MQL method. Research limitations/implications: Environmental considerations and having to conform to increasingly stringent regulations related to environmental protection and employee safety motivate researchers and businesses to entirely eliminate or reduce the use of grinding fluids in the grinding process and, therefore, to optimise grinding technology. Practical implications: Modern manufacturing industry requires the grinding process, which follows heat and chemical treatment, to be performed with the highest possible efficiency. However, retaining high parameters of the technological outer layer in comparison to the sample material following vacuum carburisation (before grinding) is extremely difficult. An optimised configuration of parameters of the grinding process and method of supplying grinding fluids enables meeting the current and future high expectations of the industry in this regard. Originality/value: The tests have enabled us to determine the impact of the applied vw workpiece speed and method of supplying grinding fluid on microhardness and residual stresses. Generally speaking, grinding with an electrocorundum grinding wheel results in a deterioration of residual stresses. For both methods of supplying GF (WET and MQL), the distribution of microhardness in the material of the samples ground with the highest workpiece speed (18.0 m/min) indicated no significant differences with regard to the distribution of microhardness in the material of the samples following heat and chemical treatment.
Źródło:
Archives of Materials Science and Engineering; 2022, 115, 2; 66--75
1897-2764
Pojawia się w:
Archives of Materials Science and Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The Role of Subaquatic Springs in the Formation of Flow, Temperature and Chemical Composition of River Water in the Reserve
Autorzy:
Vaganov, Sergey
Blinov, Sergey
Belkin, Pavel
Perevoshchikov, Roman
Powiązania:
https://bibliotekanauki.pl/articles/2068457.pdf
Data publikacji:
2022
Wydawca:
Polskie Towarzystwo Inżynierii Ekologicznej
Tematy:
karst
groundwater
surface water
subaquatic spring
chemical composition
river flow formation
temperature regime
nature reserve
Opis:
A study of the effect of subaquatic discharge of karst groundwater sources on the composition of the Vishera River, the largest tributary of the Kama River, was carried out. The study was carried out on the territory of the State Nature Reserve "Vishersky" and included the determination of the flow rate, temperature as well as chemical composition of natural waters. Six zones of karst groundwater discharge and their influence on the water regime of the Vishera river were studied in detail. It was shown that subaquatic sources in the places of their discharge, forming up to 36% of the river flow, significantly affect the temperature regime. A significant part of dissolved substances, primarily calcium ions and hydrocarbonate ions, as well as some trace elements (Li, Sr, V, Cr) enter the Vishery river with karst waters. The results of the study show that monitoring the composition and properties of groundwater discharged covertly in the river channel is an important part of the monitoring of water bodies of both protected and developed areas.
Źródło:
Journal of Ecological Engineering; 2022, 23, 3; 39--48
2299-8993
Pojawia się w:
Journal of Ecological Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Numerical aided design of Pelton nozzle jet deflector
Autorzy:
Popovski, Boro
Lipej, Andrej
Powiązania:
https://bibliotekanauki.pl/articles/2052244.pdf
Data publikacji:
2021
Wydawca:
Politechnika Koszalińska. Wydawnictwo Uczelniane
Tematy:
water turbine
Pelton turbine
jet deflector
free surface flow
numerical analysis
turbina wodna
turbina Peltona
przepływ ze swobodną powierzchnią
analiza numeryczna
Opis:
Hydro energy still occupies an important place among renewable energy sources. In special operating conditions, Pelton turbines are irreplaceable and can be used for extremely small hydropower plants and also large hydro power plants. Pelton turbines can operate with high head and relatively small flow rates. In many cases, the height differences of the water are very large. Sometimes it is necessary to stop the operation of the turbine very quickly and the consequences of water hammer can be very severe. The responsible part to minimize the consequences of this phenomena is jet deflector, which can be in two different technical designs. The steps for 3-D geometry definition, pre-processing and post-processing, flow modelling and FEM analysis are presented. In the paper is presented the new optimized design of push-out jet deflector shape. Optimization consider 3-D CFD analysis of free surface flow and stress analysis. The main goal of the research was to minimize the influence of all force components on the torque of deflector servomotor. The final results present the geometry of the deflector, with a significant reduction in the stresses and deformations. These have been achieved with a crucial reduction in the hydrodynamic force and torque.
Źródło:
Journal of Mechanical and Energy Engineering; 2021, 5, 2; 149-156
2544-0780
2544-1671
Pojawia się w:
Journal of Mechanical and Energy Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Rotorcraft thickness noise control
Autorzy:
Szulc, O.
Powiązania:
https://bibliotekanauki.pl/articles/38627396.pdf
Data publikacji:
2021
Wydawca:
Instytut Podstawowych Problemów Techniki PAN
Tematy:
helicopter rotor
aerodynamics
aeroacoustics
CFD
noise reduction
active flow
noise control
surface transpiration
perforation
Opis:
The paper describes an innovative idea of Thickness Noise Control (TNC) based on adoption of a flow control strategy (i.e. surface ventilation) for acoustic attenuation of helicopter rotor periodic noise. The TNC method is relying on incorporation of multiple cavities (closed by perforated panels and linked to low- and high-pressure reservoirs) located in a symmetrical manner at front and rear portions of the blade tip. The efficiency of the new approach is verified using a two-bladed model rotor of Purcell (untwisted variant of the blade of Bell UH-1H Iroquois helicopter) in low-thrust hover conditions. The results of numerical simulations, obtained with CFD solver (Spalart–Allmaras turbulence and Bohning–Doerffer transpiration models), indicate that in the near-field of the blade tip, both the amplitude and spectral contents of pressure impulses of emitted thickness noise are significantly improved. The TNC method, in the proposed unsteady mode of operation, turns out to be a suitable means of thickness noise reduction in forward flight. Moreover, it is demonstrated that by proper azimuthal activation the efficiency is almost unaltered, while the rotor torque penalty and required transpiration mass-flux are decreased by a factor of 3–5 compared to a steady arrangement.
Źródło:
Archives of Mechanics; 2021, 73, 4; 391-417
0373-2029
Pojawia się w:
Archives of Mechanics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Three dimensional MHD Casson fluid flow over a stretching surface with variable thermal conductivity
Autorzy:
Ganga, B.
Charles, S.
Abdul Hakeem, A. K.
Nadeem, S.
Powiązania:
https://bibliotekanauki.pl/articles/1839858.pdf
Data publikacji:
2021
Wydawca:
Politechnika Częstochowska. Wydawnictwo Politechniki Częstochowskiej
Tematy:
three-dimensional flow
Casson fluid
stretching surface
heat generation
trójwymiarowy przepływ
przepływ trójwymiarowy
przepływ magnetohydrodynamiczny
MHD
płyn Cassona
rozciąganie powierzchni
wytwarzanie ciepła
przewodność cieplna
Opis:
The three-dimensional magnetohydrodynamic (MHD) boundary layer flow of a Casson fluid over a stretching surface set into a porous medium with variable thermal conductivity and heat generation/absorption has been researched. Conservation laws of mass, momentum and energy are changed into ordinary differential equations, which are numerically dealt with by applying the fourth order Runge-Kutta integration scheme in relationship with shooting procedure. The dimensionless velocity, temperature, skin friction coefficient and the local Nusselt number inside the boundary layer are processed and examined through tables and illustrations for various physical parameters. The numerical outcomes obtained for the specific case are sensible in great concurrence with the existing results. Results indicate that momentum boundary layer reduces for the Hartman number and Casson fluid parameter. Temperature is found as an enlightened function for the heat generation and thermal conductivity parameter.
Źródło:
Journal of Applied Mathematics and Computational Mechanics; 2021, 20, 1; 25-36
2299-9965
Pojawia się w:
Journal of Applied Mathematics and Computational Mechanics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Treatment of Craft Brewery Sewage with SS VF and FWS Constructed Wetland – Lab Scale Experiment
Autorzy:
Dąbrowski, Wojciech
Karolinczak, Beata
Malinowski, Paweł
Lech, Magrel
Powiązania:
https://bibliotekanauki.pl/articles/2069918.pdf
Data publikacji:
2021
Wydawca:
Politechnika Koszalińska. Wydawnictwo Uczelniane
Tematy:
craft brewery
sewage treatment
constructed wetlands
subsurface flow system
surface flow system
Opis:
The problem of wastewater treatment from craft breweries emerged in Poland about 10 years ago when an increase in the number of small breweries was observed. Plants located in small towns are forced to solve the problem on their own. One of the possibilities is to use low-cost technology of constructed wetlands with subsurface and surface flow. The purpose of the research was to test the possibility of effective treatment of sewage from a craft brewery in a lab-scale research installation and to determine the parameters for designing a real scale plant. Wastewater from the Waszczukowe brewery was used in the study. The research system consisted of a retention and aeration tank, SS-VF subsurface flow and FWS surface flow beds. An innovative Certyd filling produced by LSA company was used. The high efficiency of SS-VF bed and the entire research system was found. The removal efficiency in SS VF was on average 89.7% for BOD5, 90.5% for COD, 54.6% for TN and 52.1% for TP. For whole treatment it was respectively 97.1%, 96.7%, 72.6% and 61.3%. A high organic matter removal effect was found for the SS-VF bed (87.1 g BOD5g m-2 d-1) and a relatively low for the FWS (3.0 BOD5g m-2 d-1). The study confirmed the need for plant design based on hydraulic load and required load removed per unit area.
Źródło:
Rocznik Ochrona Środowiska; 2021, 23; 290--300
1506-218X
Pojawia się w:
Rocznik Ochrona Środowiska
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Visualization of River Water Flow in Hydrodynamically Active Areas under Different Flow Regimes
Autorzy:
Snitynskyi, Volodymyr
Khirivskyi, Petro
Hnativ, Ihor
Yakhno, Oleg
Machuga, Oleg
Hnativ, Roman
Powiązania:
https://bibliotekanauki.pl/articles/1955557.pdf
Data publikacji:
2021
Wydawca:
Polskie Towarzystwo Inżynierii Ekologicznej
Tematy:
mountain river
self-cleaning process
surface waters
hydrodynamically active area
flow visualization
cavitation phenomena
Opis:
It was established that in the territory of the Stryi river basin, the natural landscapes are maximally preserved in comparison with other regions of Western Ukraine, but under modern conditions an increase of negative anthropogenic impact on the quality of natural waters is observed. The hydrodynamic barriers or hydrodynamically active areas (HAA) of mountain rivers, characterized by a significant oxygen saturation of the water flow, which activates the processes of biochemical and biological self-purification of surface waters, are important for the efficiency of self-purification processes. In order to verify the results of theoretical and field research, an existing experimental setup was designed and improved. It provided the conditions for modeling the flow of mountain rivers in accordance with the laws of similarity theory and the principles of hydrodynamic modeling. On the basis of the results of field observations in the foothills of rivers, as well as regulatory and design documentation, the limits of the main operating factors were determined, namely the Freud number, flow depth and flow rate, which are decisive in studying the impact of HAA on flow self-cleaning processes. By changing the length of the tray section, the gullies and the waterfall niche of the real hydrodynamically active section were simulated, on which field experiments on the Tyshivnytsia River were conducted. In the studies, measurements were performed at different flow regimes, which simulated different hydrological parameters. In order to analyze the impact of HAA on self-cleaning processes, the flow was visualized using photography. The change in the structure of a stream of natural waters at passage of HAA was established. The high oxygen saturation of the river waters of the Stryi river basin is caused by the influence of HAA, which contribute to the purification of polluted waters from biological pollutants and other man-made pollutants and form the high quality of water resources in the region. A method of modeling and visualization of mountain rivers in the laboratory was developed.
Źródło:
Journal of Ecological Engineering; 2021, 22, 9; 129-135
2299-8993
Pojawia się w:
Journal of Ecological Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Acoustic propagation in inhomogeneous fluids: regularization via the introduction of fine particles
Autorzy:
Jordan, P. M.
Powiązania:
https://bibliotekanauki.pl/articles/38440473.pdf
Data publikacji:
2020
Wydawca:
Instytut Podstawowych Problemów Techniki PAN
Tematy:
inhomogeneous fluids
Laplace transform
particle-laden flow
singular surface theory
Opis:
It is shown, using analytical methodologies, that the velocity field blow-up suffered by vertically ascending acoustic waves in an isothermal atmosphere can be eliminated via the introduction of fine particles. Assuming the inhomogeneous generalization of the particle-laden flow model known as the (linearized) Marble–Thompson model-1, it is established that bounded, exponentially decreasing, shock amplitudes can be obtained provided the mass fraction of particles exceeds a critical value, for which an exact expression is derived. Lastly, supporting numerical results are presented, special cases are discussed, and possible follow-on studies are noted.
Źródło:
Archives of Mechanics; 2020, 72, 1; 59-73
0373-2029
Pojawia się w:
Archives of Mechanics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Heat transfer enhancement from a heated plate with hemispherical convex dimples by forced convection along with a cross flow jet impingement
Autorzy:
Patro, P.
Garnayak, S.
Powiązania:
https://bibliotekanauki.pl/articles/265024.pdf
Data publikacji:
2020
Wydawca:
Uniwersytet Zielonogórski. Oficyna Wydawnicza
Tematy:
wymiana ciepła
uderzenie strumieniowe
przepływ krzyżowy
heat transfer enhancement
jet impingement
convex dimpled surface
SST k-w model
cross flow
Opis:
In the present study, heat transfer from a small three dimensional rectangular channel due to turbulent jet impinging from a nozzle normal to the main flow at the inlet has been investigated. Hemispherical convex dimples are attached to the bottom plate from where heat transfer calculations are to be performed. Numerical simulations were performed using the finite volume method with […] turbulence model. The duct and nozzle Reynolds number are varied in the range of […], respectively. Different nozzle positions (X/D = 10.57, 12.88, 15.19) along the axial direction of the rectangular duct have been considered. It has been found that higher heat transfer is observed at X/D = 10.57 as compared to the other positions. The heat transfer enhancements with and without cross-flow effects have also been compared. It has been shown that the heat transfer rate with cross-flow is found to be much higher than that without crossflow. Also, the effect of dimples on the heated surface on heat transfer was investigated. The heat transfer is found to be greater in the presence of a dimpled surface than a plane surface.
Źródło:
International Journal of Applied Mechanics and Engineering; 2020, 25, 1; 127-141
1734-4492
2353-9003
Pojawia się w:
International Journal of Applied Mechanics and Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Wyświetlanie 1-15 z 66

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