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Search results for: FRICTIONAL PRESSURE DROP
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Prediction of coking dynamics for wet coal charge
PublicationA one-dimensional transient mathematical model describing thermal and flow phenomena during coal coking in an oven chamber was studied in the paper. It also accounts for heat conduction in the ceramic oven wall when assuming a constant temperature at the heating channel side. The model was solved numerically using partly implicit methods for gas flow and heat transfer problems. The histories of temperature, gas evolution and internal...
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APPLICATION OF THE THEORY OF SEMI-MARKOV PROCESSES TO DETERMINE A LIMITING DISTRIBUTION OF THE PROCESS OF CHANGES OF ABILITY AND INABILITY STATES OF FUEL SUPPLY SYSTEMS IN HEAVY FUEL DIESEL ENGINES
PublicationThe paper presents applicability of the theory of semi-Markov processes to determine a limiting distribution of the process of changes of technical states of fuel systems for marine engines running on heavy fuel oils. The proposed study of this process includes the components of such fuel systems like: 1 - injectors, 2 - high pressure hoses, 3 - injection pumps, 4 - low pressure hoses, 5 – fine filters, 6 - coarse filters, 7 – fuel-feed...
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An isogeometric finite element formulation for frictionless contact of Cosserat rods with unconstrained directors
PublicationThis paper presents an isogeometric finite element formulation for nonlinear beams with impenetrability constraints, based on the kinematics of Cosserat rods with unconstrained directors. The beam cross-sectional deformation is represented by director vectors of an arbitrary order. For the frictionless lateral beam-to-beam contact, a surface-to-surface contact algorithm combined with an active set strategy and a penalty method...
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Porównanie mocy strat energetycznych w pompie wyporowej o zmiennej wydajności określonych bez uwzględnienia bądź z uwzględnieniem mocy ściskania oleju hydraulicznego
PublicationPorównano moce strat energetycznych w pompie wyporowej o zmiennej wydajności, określone bez uwzględnienia bądź z uwzględnieniem mocy ściskania oleju hydraulicznego. Ocena mocy ściskania cieczy w pompie stała się możliwa dzięki zastosowaniu, zaproponowanej przez autora, metody określenia stopnia zapowietrzenia cieczy w pompie. W metodzie określenia stopnia zapowietrzenia cieczy w pompie oraz w ocenie mocy strat objętościowych ściskania...
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Container port expansion towards the sea in the context of maritime spatial planning
PublicationThe growth of ships causes a significant increase in demand for new port surfaces and demands for the depths of water bodies in the ports. Due to technological changes in the transshipment and development pressure ports lacks space and they move towards the sea with their activities. The paper discusses the reasons for the phenomenon of expansion of ports towards the sea and its effects on maritime spatial planning.
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Influence of IED Explosion on Lateral Dynamics of a Vehicle
PublicationThe paper describes field test results of heavy vehicle tire blow-outs. Both civilian and military vehicles are subjected to sudden loss of inflation pressure in one or more wheels, often accompanied by serious tire damage. Selected results related to the lateral dynamic of vehicle during and just after explosive tire destruction are reported
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Suitability study of hybrid model of electrodynamic actuator
PublicationThis paper presents the proposal of the hybrid circuit-field model of an electrodynamic actuator. The field model uses the inductor current as the input data which is obtained from the circuit model or experimentally. The field model implemented using the FLUX program makes it possible to easily determine the pressure distribution acting on the disc. The results have been verified experimentally.
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Free convection of water-Al2O3 nanofluid from horizontal porous coated tube
PublicationThe main aim of the present study was to investigate the influence of nanoparticles on heat transfer coefficients during free convection of water-Al2O3 nanofluid from horizontal porous coated tube under atmospheric pressure for nanoparticle concentration of 0.01% by weight. Contrary to published data present study concerns on free convection of nanofluids in extensive, quiescent fluid.
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The Method of Multi-criteria Analysis to Support the Decision on Load or Micro-generation Connection to a Low- or Medium-voltage Power Grid
PublicationThis paper presents a method that supports the decision in terms on selecting the best option of a load connection to a low- or medium-voltage power distribution grid, and of a micro-generation source connection to a low-voltage grid. The method is based on the search for the option with the lowest aggregate assessment measure, which is the weighted average of partial assessment measures determined for each of eight considered...
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Optoelectronic device for hematocrit measurements
PublicationAn optoelectronic system for measurements of hematocrit level (HCT) in the whole human blood is presented. Proposed system integrates a dedicated optoelectronic sensor, a microcontroller and a small LCD display in a low cost, battery-powered, handheld device. Chosen method for determining blood hematocrit level is based on optical properties of whole blood in visible and NIR wavelength range. Measurements with the use of proposed...
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Investigation of natural frequencies of axially loaded thin-walled columns
PublicationThe paper deals with correlation between natural frequencies of two steel thin-walled columns and the corresponding applied load. The structures are made of cold-formed lipped channel sections. The columns lengths were assumed to follow two buckling patterns – global flexural and flexural-torsional buckling. In the thicker structure two material models were considered – linearly-elastic and elastic-perfectly plastic. Numerical...
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Evaluation of Three Peptide Immobilization Techniques on a QCM Surface Related to Acetaldehyde Responses in the Gas Phase
PublicationThe quartz-crystal microbalance is a sensitive and universal tool for measuring concentrations of various gases in the air. Biochemical functionalization of the QCM electrode allows a label-free detection of specific molecular interactions with high sensitivity and specificity. In addition, it enables a real-time determination of its kinetic rates and affinity constants. This makes QCM a versatile bioanalytical screening tool for...
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Estimation of Oxidative Stress Markers in Chronic Kidney Disease
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Qualification of brazing procedure for furnace brazing of austenitic steel according to requirements of the ASME BPVC section IX
PublicationThe article presents the procedure for qualifying brazing technology in a vacuum furnace on the example of stainless steel elements joined with copper filler material from the F-No group. 105, in accordance with the ASME Sec. IX, part QB (ASME Boiler and Pressure Vessel Code. Qualification Standard for Welding, Brazing and Fusing; Procedures; Welders; Brazers; and Welding, Brazing and Fusing Operators). The essential variables...
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Direct-Ultrasonic Assisted Microextraction Coupled with RTL-GC-FID/GC-MS as a Future Standard Procedure for Monitoring 26 potentially Allergenic Fragrances in Water Samples
PublicationThis research topic grew up as a result of awareness of constant anthropogenic and natural input to the environment constituents of personal care products (PCPs) residues. This group of emerging pollutants encompasses a wide range of chemicals, including potentially allergenic fragrance compounds. The aim of the present study was to investigate presence of 26 fragrance allergens in water samples. Simple and rapid methodology based...
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SUBSOIL CHARACTERISTICS OF THE VISTULA RIVER DIKES
PublicationThe results of CPTU tests are used to determine the strength parameters of a dike subsoil. Stress state and stress history of the subsoil under the flood embankment was evaluated with CPTU and DMT tests. Normally consolidated soil was found under the central part of the dike, while the subsoil near the dike toe is found to be overconsolidated. Due to consolidation the undrained shear strength of the subsoil under the central part...
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New method to monitor changes in the subarachnoid width and pial artery pulsation for physiological and clinical research
PublicationThere are several medical conditions associated with brain oedema such as traumatic brain injury, intoxication or tumors. Brain edema and related brain parenchyma expansion may lead to compression and subsequent injury of several brain structures. So far, the only method enabling detection and monitoring of the progress a cerebral oedema in a patient, has been monitoring of intracranial pressure (ICP) with a pressure probe inserted...
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EFFECT OF PRESS DRYING ON DIMENSION STABILITY AND DENSITY OF BEECH WOOD,
PublicationTimber is traditionally dried in kilns by processes that often take several days or weeks to complete. At present, it is possible to apply several methods of rapid drying of timber, including, for example, press drying. This research is based on the use of this process. Drying was performed using the heating plates with a temperature of 160 °C. Three pressures were compared in the research 1.0 MPa, 1.4 MPa, and 1.8 MPa. The density...
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Simulations of air and water flow in a model dike during overflow experiments
PublicationFlow in flood dikes, earth dams, and embankments occurs in variably saturated conditions, with pores of the earth material filled partly with water and partly with air. In routine engineering analysis, the influence of pore air is neglected and the air pressure is assumed equal to atmospheric. In some circumstances, for example, during overtopping of the dike by water, the effect of pore air on water flow and stability of the structure...
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Effects of consecutive apneas on pial artery pulsation and subarachnoid width in healthy subjects
PublicationHypercapnia is known to dilate the pial artery, disrupt cerebral autoregulation and increase pial artery pulsation. The cerebral blood flow velocity (CBFV) response to hypercapnia is biphasic. Below the threshold for the increase of blood pressure (BP) with carbon dioxide partial pressure (pCO2), the CBFV measurement reflects vascular reactivity to pCO2 alone at a constant BP. Above this threshold, the CBFV measurement provides...
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Niekonwencjonalne koła pojazdów
PublicationPrzedstawiono sposoby zapobiegania skutkom utraty ciśnienia w oponach pneumatycznych. Zaprezentowano koła niepneumatyczne, zastosowane w pojeździe księżycowym. Omówiono wyniki badań kół kompozytowych. Przedstawiono najnowsze rozwiązania konstrukcyjne koł niepneumatycznych przeznaczonych do pojazdów mechanicznych.
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Szybkie uziemniki do ograniczania skutków zwarć łukowych w okrętowych rozdzielnicach SN
PublicationW artykule scharakteryzowano moc i napięcie łuku, jak również przedstawiono model termodynamiczny służący do obliczania ciśnienia i temperatury gazów w otoczeniu łuku zwarciowego. Przedstawiono przykładowy układ elektrowni okrętowej i zasilania najważniejszych odbiorników na statku do przewozu gazu ziemnego w stanie ciekłym. Na podstawie parametrów prądnic i silników odbiorników zasilanych z rozdzielnicy głównej obliczono prądy...
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The Method of reduction of aerodynamic forces generated in turbine blade seals
PublicationThe distibution of pressure in the seal gaps does not only affect the so called '' leakage losses'' and the turbine stage overall efficiency but also plays an important role in the generation of aerodynamic forces which may cause self-excited rotor vibrations. The paper describes a chamber seal applied for the reduction of the aerodynamic forces created in shroud seals. This kind of turbine seal was patented and tested.
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Compact satellite hydraulic unit
PublicationThe article describes the design and operation of a prototype hydraulic unit. It is based on an inversed kinematics, satellite pump in which the body rotates around the shaft. The pump is placed inside the electric motor. Thanks to that the compact and low mass construction was achieved. Thanks to new commutation unit with enlarged channels, lower pressure losses were obtained. The article presents the construction and results...
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Numerical Analysis of the Unsteady Propeller Performance in the Ship Wake Modified by Different Wake Improvement Devices
PublicationThe paper presents summary of numerical analysis of the unsteady propeller forces and induced pressure pulses generated by the selected real propeller of 7000 tons product tanker, operating in five different wakefields including four inflenced by the different wake improvement devices. The results of the analysis are partly compared with experimental data and univocal conclusions about the optimum wake improvement device are presented.
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Przykłady realizacji i interpretacji wyników sondażowych pomiarów terenowych w czynnych systemach wodociągowych
PublicationW pracy przedstawiono przebieg realizacji i rezultaty sondażowych pomiarów terenowych w trzech układach dystrybucji wody o zróżnicowanym przewymiarowaniu sieci wodociągowej. Pomiary przeprowadzono w dążeniu do identyfikacji właściwości (cech) strukturalnych i funkcjonalnych układów po wieloletniej ich eksploatacji. Ustalenia te determinują opracowanie programu realizacji pomiarów dla potrzeb tarowania komputerowego modelu przepływu...
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Przykłady realizacji i interpretacji wyników sondażowych pomiarów terenowych w czynnych systemach dystrybucji wody
PublicationW pracy przedstawiono przebieg realizacji i rezultaty sondażowych pomiarów terenowych w trzech układach dystrybucji wody o zróżnicowanym przewymiarowaniu sieci wodociągowej. Pomiary przeprowadzono w dążeniu do identyfikacji właściwości (cech) strukturalnych i funkcjonalnych układów po wieloletniej ich eksploatacji. Ustalenia te determinują opracowanie programu realizacji pomiarów dla potrzeb tarowania komputerowego modelu przepływu...
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Structural properties of foil bearings: a closed-form solution validated with finite element analysis
PublicationFluid film thickness in a compliant foil bearing is greatly influenced by the deflection of the bearing structure. Therefore, in order to properly model performance of a foil bearing, it is mandatory that the deflection of the compliant bearing structure due to the generated hydrodynamic pressure is determined accurately. This article proposes an easy-to-use two-dimensional model, which takes into account detailed geometry of the...
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Modelling study of flow boiling heat transfer of perspective fluids for refrigeration technology
PublicationThere is a gap of knowledge on flow boiling at high saturation temperatures and higher values of reduced pressure. Thus far, the in-house developed semi-empirical model for flow boiling and flow condensation showed a satisfactory accuracy for calculations for various refrigeration fluids for a wide scope of reduced pressures. This study presents results of calculations of heat transfer coefficient of perspective refrigeration fluids,...
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Time-Domain Description of Point-Source Acoustic Wavefields as a Useful Approach in Ultrasonic Techniques
PublicationIn traditional acoustics, field problems are usually treated in the frequency domain, broadband fields being reduced to superposition of harmonic spectrum components. However, this approach is inherently acausal and it is known that in case of arbitrary signals, the distribution-based, time-domain description can be more effective. The present paper is an attempt to expand the time-domain linear systems formalism onto space problems...
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Multi-objective optimization of tool wear, surface roughness, and material removal rate in finishing honing processes using adaptive neural fuzzy inference systems
PublicationHoning processes are usually employed to manufacture combustion engine cylinders and hydraulic cylinders. A crosshatch pattern is obtained that favors the oil flow. In this paper, Adaptive Neural Fuzzy Inference System (ANFIS) models were obtained for tool wear, average roughness Ra, cylindricity and material removal rate in finish honing processes. In addition, multi-objective optimization with the desirability function method...
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Time-domain description of point-source acoustic wavefields as a useful approach in ultrasonic techniques
PublicationIn traditional acoustics, field problems are usually treated in the frequency domain, broadband fields being reduced to superposition of harmonic spectrum components. However, this approach is inherently acausal and it is known that in case of arbitrary signals, the distribution-based, time-domain description can be more effective. The present paper is an attempt to expand the time-domain linear systems formalism onto space problems...
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Influence of geometrical and operational parameters on tooth wear in the working mechanism of a satellite motor
PublicationThis article describes the phenomena affecting the wear of the rotor of the working mechanism in a hydraulic satellite motor. The basic geometrical relationships that allow the calculation of the coordinates of the points of contact between the satellite and the rotor and the curvature are presented. A method for calculating the number of contacts of the satellite teeth with the rotor teeth and of the satellite teeth with the curvature...
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A Novel Approach to Fully Nonlinear Mathematical Modeling of Tectonic Plates
PublicationThe motion of the Earth's layers due to internal pressures is simulated in this research with an efficient mathematical model. The Earth, which revolves around its axis of rotation and is under internal pressure, will change the shape and displacement of the internal layers and tectonic plates. Applied mathematical models are based on a new approach to shell theory involving both two and three-dimensional approaches. It is the...
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Cyclic behavior of FeCoCrNiMn high entropy alloy coatings produced through cold spray
PublicationeCoCrNiMn high entropy alloy powders were employed to produce coatings on carbon steel through high pressure cold spray (at 1100 °C and 7 MPa in temperature and pressure respectively). X-ray diffraction of the sprayed material revealed a dense coating with the retention of the original crystallographic structure. Once splatted, particles revealed high flattening ratio with consequent excellent adhesion of the coating to the substrate....
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Sounding Mechanism of a Flue Organ Pipe—A Multi-Sensor Measurement Approach
PublicationThis work presents an approach that integrates the results of measuring, analyzing, and modeling air flow phenomena driven by pressurized air in a flue organ pipe. The investigation concerns a Bourdon organ pipe. Measurements are performed in an anechoic chamber using the Cartesian robot equipped with a 3D acoustic vector sensor (AVS) that acquires both acoustic pressure and air particle velocity. Also, a high-speed camera is employed...
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Effect of power frequency on the stress state of disc actuator
PublicationThis paper presents the concept of determining the optimum frequency of coil supply in inductive-dynamic drive. As a criterion to obtain the sought frequency, the smallest value of reduced stress in the disc was assumed while maintaining the desired dynamics. The disc stress is determined on the basis of solution of vibrating thin plate equation. Magnetic pressure acting on the disc is obtained from a hybrid circumferentially-field...
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Manufacturing of Lightweight Aggregates as an Auspicious Method of Sewage Sludge Utilization
Publication: Sewage sludge is a high-volume and low-cost waste commonly generated worldwide, so its utilization is a vital issue. The application of this waste in the manufacturing of lightweight aggregates was investigated. The process was performed using intensive mixers with volumes of 5 and 30 L, as well as the industrial 500 L mixer. Then, granulates were sintered in a tube furnace. The influence of composition and mixer size on the...
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Crack propoagation in MgO-PSZ ceramic materials
PublicationThe properties of ceramic materials such as elevated hardness, high temperature capability, low coefficient of thermal expansion are of interest for rolling element materials. Widely used ceramic materials in engineering applications are silicon nitride, zirconia and alumina. The paper presents an experimental study of the fatigue life of MgO-PSZ ceramic material in lubricated contact with defined types of cracks. A ceramic angular...
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Preparation and Characterization of Au/Pd Modified-TiO2 Photocatalysts for Phenol and Toluene Degradation under Visible Light—The Effect of Calcination Temperature
PublicationRutile loaded with Au/Pd nanoparticles was prepared using a water-in-oil microemulsion system of water/AOT/cyclohexane followed by calcination.Theeffect of calcination temperature (from350 to 700∘C) on the structure ofAu/Pd nanoparticles deposited at rutile matrix and the photocatalytic properties of Au/Pd-TiO2 was investigated in two model reactions (toluene degradation in gas phase and phenol degradation in aqueous phase). The...
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Light intensity analysis of photovoltaic parameters for perovskite solar cells
PublicationThe number of publications on perovskite solar cells (PSC) continues to grow exponentially. Although the efficiency of PSC is exceeded 25.5%, not every research laboratory can reproduce this result or even pass the border of 20%. Unfortunately, it is not always clear which dominating mechanism is responsible for the performance drop. Here, we develop a simple method of light intensity analysis of JV parameters allowing the understanding...
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Copper Slag as a Potential Waste Filler for Polyethylene-Based Composites Manufacturing
PublicationThe present study aimed to analyze the application of waste material from copper production– copper slag (ŻŻL) as filler for composites based on the high-density polyethylene (HDPE). Copper slag filler was introduced in the amounts of 1–20 wt%, and its influence on the appearance (color analysis), chemical structure (Fourier-transform infrared (FTIR) spectroscopy), microstructure (optical microscopy), as well as static (tensile...
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Tribo-Environment Dependent Chemical Modification of Sliding Interfaces in Ultrananocrystalline Diamond Nanowall Film: A Correlation with Friction and Wear
PublicationTribological properties of ultrananocrystalline diamond nanowall (UNCD NW) films were investigated quantitatively in three different and controlled tribo-environmental conditions, proposing the passivation and graphitization mechanisms. However, these mechanisms are rather complicated and possibly can be understood in well-controlled tribological conditions. It was shown that the friction and wear of these films were high in highPage 1...
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Modelling of subarachnoid space width changes in apnoea resulting as a function of blood flow parameters
PublicationDuring apnoea, the pial artery is subjected to two opposite physiological processes: vasoconstriction due to elevated blood pressure and vasorelaxation driven by rising pH in the brain parenchyma. We hypothesized that the pial artery response to apnoea may vary, depending on which process dominate. Apnoea experiments were performed in a group of 19 healthy, non-smoking volunteers (9 men and 10 women). The following parameters...
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Pial artery and subarachnoid width response to apnoea in normal humans
PublicationBackground: Little is known about intracranial pressure (ICP)-cerebral haemodynamic interplay during repetitive apnoea. A recently developed method based on near-infrared transillumination/backscattering sounding (NIR-T/BSS) noninvasively measures changes in pial artery pulsation (cc-TQ) as well as subarachnoid width (sas-TQ) in humans. Method: We tested the complex response of the pial artery and subarachnoid width to apnoea...
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Organic Rankine cycle as bottoming cycle to a combined Brayton and Clausius - Rankine cycle
PublicationA preliminary evaluation has been made of a possibility of bottoming of a conventional Brayton cycle cooperating with the CHP power plant with the organic Rankine cycle installation. Such solution contributes to the possibility of annual operation of that power plant, except of operation only in periods when there is a demand for the heat. Additional benefit would be the fact that an optimized backpressure steam cycle has the advantage...
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Understanding the kinetics and atmospheric degradation mechanism of chlorotrifluoroethylene (CF2=CFCl) initiated by OH radicals
PublicationThe atmospheric degradation of chlorotrifluoroethylene (CTFE) by OH˙ was investigated using density functional theory (DFT). The potential energy surfaces were also defined in terms of single-point energies derived from the linked cluster CCSD(T) theory. With an energy barrier of −2.62 to −0.99 kcal mol−1 using the M06-2x method, the negative temperature dependence was determined. The OH˙ attack on Cα and Cβ atoms (labeled pathways...
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The luminescence study of LiGa5(1−x)O8:5xCr3+ coumpounds
Open Research DataInfrared luminescent materials have evoked much attention from chemists and material scientists. Although substantial progress is made in materials design, the luminescent mechanism remains ambiguous in the complex structures, presenting major barriers to developing novel infrared luminescent materials. Herein, this study aims to deliberate a complete...
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Modelowanie przepływu pary przez okołodźwiękowe wieńce turbinowe z użyciem sztucznych sieci neuronoych
PublicationNiniejszy artykuł stanowi opis modelu przepływu pary przez okołodźwiękowe stopnie turbinowe, stworzonego w oparciu o sztuczne sieci neuronowe (SSN). Przedstawiony model neuronowy pozwala na wyznaczenie rozkładu wybranych parametrów w analizowanym przekroju kanału przepływowego turbiny dla rozpatrywanego zakresu wartości ciśnienia wlotowego.
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Model matematyczny strat objętościowych ściskania oleju hydraulicznego w pompie wyporowej o zmiennej wydajności
PublicationCelem pracy było stworzenie możliwości oceny strat objętościowych wynikających ze ściskania oleju hydraulicznego w komorach roboczych wysokociśnieniowej pompy wyporowej o zmiennej wydajności na obrót wału. Straty objętościowe ściskania oleju muszą być określone jako funkcje tych samych parametrów, w zależności od których ocenione są straty objętościowe przecieków oleju w komorach, wynikające z jakości rozwiązania konstrukcyjnego...