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Search results for: VELOCITY OF THE PRESSURE WAVE
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Wave energy attenuation in fields of colliding ice floes. Part A: Discrete-element modelling of dissipation due to ice–water drag
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Psychological burden and disease-related quality of life in dialysis patients during the first wave of the COVID-19 pandemic — a cross-sectional observational study
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Revalorisation of the Szewalski’s concept of the law of varying the last-stage blade retraction in a gas-steam turbine
PublicationThe article presents the implementations of the free vortex law to the blade of the last stage of a gas-steam turbine. First, a thermodynamic analysis was carried out, determining the parameters at the inlet, then the number of stages of the high and low-pressure part of the turbine was constructed, together with the kinematics and velocity vectors for subsequent stages of the axial turbine. The last step of article was to take...
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Standing Waves in a Rectangular Resonator Containing Acoustically Active Gases
PublicationThe distribution of perturbations of pressure and velocity in a rectangular resonator is considered. A resonator contains a gas where thermodynamic processes take place, such as exothermic chemical reaction or excitation of vibrational degrees of a molecule’s freedom. These processes make the gas acoustically active under some conditions. We conclude that the incident and reflected compounds of a sound beam do not interact in the...
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Improved model of isothermal and incompressible fluid flow in pipelines versus the Darcy–Weisbach equation and the issue of friction factor
PublicationIn this article, we consider the modelling of stationary incompressible and isothermal one-dimensional fluid flow through a long pipeline. The approximation of the average pressure in the developed model by the arithmetic mean of inlet and outlet pressures leads to the known empirical Darcy–Weisbach equation. Most importantly, we also present another improved approach that is more accurate because the average pressure is estimated...
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Instrumentation optical fibres for wave transformation, signal processing, sensors, and photonic functional components, manufactured at Białystok University of Technology in Dorosz Fibre Optics Laboratory
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Hysteresis curves for some periodic and aperiodic perturbations in magnetosonic flow
PublicationA thermodynamic relation between perturbations of pressure and mass density in the magnetohydrodynamic flow is theoretically studied. Planar magnetohydrodynamic perturbations with the wave vector, which forms a constant angle with the equilibrium magnetic field, are under study. The theory considers thermal conduction of a plasma and the deviation from adiabaticity of a flow due to some kind of heating–cooling function. It also...
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The effect of pressure on heat transfer during pool boiling of water-Al2O3 and water-Cu nanofluids on stainless steel smooth tube
PublicationPrzedstawiono wyniki badań eksperymentalnych wrzenia nanocieczy woda-Al2O3 i woda-Cu o koncentracjach nanocząstek 0.01%, 0.1% oraz 1% przy ciśnieniu absolutnym 10 kPa, 100 kPa oraz 200k Pa.
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Effects of osmotic and high pressure stress on expression of virulence factors among Enterococcus spp. isolated from food of animal origin
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Oxygen Aspects in the High-Pressure and High-Temperature Sintering of Semiconductor Kesterite Cu2ZnSnS4 Nanopowders Prepared by a Mechanochemically-Assisted Synthesis Method
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Antibacterial Activity of Fructose-Stabilized Silver Nanoparticles Produced by Direct Current Atmospheric Pressure Glow Discharge towards Quarantine Pests
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Atmospheric Pressure Glow Discharges Generated in Contact with Flowing Liquid Cathode: Production of Active Species and Application in Wastewater Purification Processes
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Production of gold nanoparticles using atmospheric pressure glow microdischarge generated in contact with a flowing liquid cathode – a design of experiments study
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The influence of stabilizers on the production of gold nanoparticles by direct current atmospheric pressure glow microdischarge generated in contact with liquid flowing cathode
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The cytoprotective role of antioxidants in mammalian cells under rapidly varying temperature, pressure and UV conditions during stratospheric balloon campaign
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Combination of High-Pressure Processing and Freeze-Drying as the Most Effective Techniques in Maintaining Biological Values and Microbiological Safety of Donor Milk
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Cold atmospheric pressure plasmas as versatile tools for effective degradation of a mixture of hazardous and endocrine disturbing compounds from liquid wastes
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The effect of pressure on heat transfer during pool boiling of water-Al2O3 and water-Cu nanofluids on stainless steel smooth tubes
PublicationPrzedstawiono wyniki badań eksperymentalnych wrzenia nanocieczy woda-Al2O3 i woda-Cu o koncentracjach nanocząstek 0.01%, 0.1% oraz 1% przy ciśnieniu absolutnym 10 kPa, 100 kPa oraz 200k Pa.
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Outcome-Driven Thresholds for Ambulatory Blood Pressure Based on the New American College of Cardiology/American Heart Association Classification of Hypertension
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Effects of Renal Sympathetic Denervation on Blood Pressure, Sleep Apnea Course, and Glycemic Control in Patients With Resistant Hypertension and Sleep Apnea
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The competence of primary care doctors in the investigation of patients with elevated blood pressure: results of a cross‐sectional study using clinical vignettes
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Influence of duration of Type 1 (insulin-dependent) diabetes mellitus on 24-h ambulatory blood pressure and heart rate profile
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Effects of extreme pressure and anti-wear additives on surface topography and tool wear during MQCL turning of AISI 1045 steel
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Plasma n-3 and n-6 polyunsaturated fatty acids association with blood pressure level in healthy males. Part 2
PublicationRegularne spożycie ryb i długołańcuchowych kwasów tłuszczowych (PUFA) rodziny n-3, pochodzenia morskiego, może obniżać ciśnienie tętnicze krwi i zmniejszać ryzyko choroby wieńcowej. Jednak wpływ poszczególnych kwasów tłuszczowych z rodziny n-3 i n-6 PUFA na ciśnienie tetnicze jest nadal kontrowersyjny. Celem pracy było określenie zależności pomiędzy wysokością ciśnienia tętniczego krwi a zawartością n-3 i n-6 PUFA w surowicy i...
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An analysis of the possibilities of increasing the production of electrical energy during the summer season by heat-generation back pressure turbine power units.
PublicationZbadano możliwości podniesienia mocy elektrycznej produkowanej przez przeciwprężne bloki ciepłownicze w sezonie letnim. Zbadano jedną z możliwości polegającą na dochładzaniu wody sieciowej powracającej z aglomeracji miejskiej. Zwrócono uwagę na aspekty techniczne, ekonomiczne i ekologiczne rozważanego rozwiązania.
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The influence of rotor-stator axial gap on the aerodynamic forces generatedin the shroud clearance of a turbine stage. Part I: Pressure field
PublicationPrzedstawiono wyniki badań doświadczalnych wpływu zmiany luzu osiowego na rozkład ciśnienia w uszczelnieniu nadbandażowym stopnia powietrznej turbiny modelowej. Wykazano, że w przypadku uszczelnienia promieniowego zmiana luzu osiowego nieznacznie zmienia rozkład ciśnienia w szczelinie nadbandażowej w porównaniu ze zmianą mimośrodowości czy skośnego ustawienia osi wirnika względem osi korpusu.
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Friction-Induced Oscillations of a Non-Asbestos Organic Pin Sliding on a Steel Disc
PublicationFriction-induced oscillations result in deterioration of performance of disc brakes and are generally undesired. We conduct experimental study of friction-induced oscillations in a non-asbestos organic material / steel pair used in disc brakes of motor vehicles. The tests are done by use of a pin-on-disc machine which has the pin sample supported on a deformable beam. The adjustable friction parameters are the disc velocity, contact...
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Investigating the current environmental situation in the Middle East and North Africa (MENA) region during the third wave of COVID-19 pandemic: urban vs. rural context
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Analysis of unsteady flow forces on the thermowell of steam temperature sensor
PublicationIn this paper, 3D numerical analysis of unsteady flow forces acting on the measuring sheath of steam temperature is presented. According to that purpose, the CFD (Computation Fluid Dynamic [1]) approach has been used. The nonstationary of fluid acting on the measuring sheath such as: Strouhal frequency, amplitude of pressure, structure of vortex, peak of pressure, field of pressure, field of velocity etc. are studied analytically...
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Antibiotic Resistance Carriage Causes a Lower Survivability Due to Stress Associated with High-Pressure Treatment among Strains from Starter Cultures
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Corrigendum to “Blood pressure disturbances and endothelial dysfunction markers in children and adolescents with type 1 diabetes” [Atherosclerosis 237 (2014) 129–134]
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Sensitive Determination of Cd in Small-Volume Samples by Miniaturized Liquid Drop Anode Atmospheric Pressure Glow Discharge Optical Emission Spectrometry
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A miniaturized atmospheric pressure glow microdischarge system generated in contact with a hanging drop electrode – a new approach to spectrochemical analysis of liquid microsamples
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Determination of mercury in mosses by novel cold vapor generation atmospheric pressure glow microdischarge optical emission spectrometry after multivariate optimization
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Size-controlled synthesis of gold nanoparticles by a novel atmospheric pressure glow discharge system with a metallic pin electrode and a flowing liquid electrode
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Development of direct-current, atmospheric-pressure, glow discharges generated in contact with flowing electrolyte solutions for elemental analysis by optical emission spectrometry
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Hanging drop cathode-atmospheric pressure glow discharge as a new method of sample introduction for inductively coupled plasma-optical emission spectrometry
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Preparation and characterization of gold nanoparticles prepared with aqueous extracts of Lamiaceae plants and the effect of follow-up treatment with atmospheric pressure glow microdischarge
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Atmospheric Pressure Plasma-Mediated Synthesis of Platinum Nanoparticles Stabilized by Poly(vinylpyrrolidone) with Application in Heat Management Systems for Internal Combustion Chambers
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Temperature and pressure dependence of the luminescence of Eu2+-doped fluoride crystals BaxSr1−xF2(x= 0, 0.3, 0.5 and 1): experiment and model
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Blood pressure control and cardiovascular risk profile in hypertensive patients from central and eastern European countries: results of the BP-CARE study
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Ambulatory Systolic Blood Pressure is Related to the Deletion Allele of the Angiotensin I Converting Enzyme Gene in Young Normotensives with Parental History of Hypertension
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Response to the queries raised by Dr M.M. Awad in a letter to editor comments on “Pressure drop of HFE7000 and HFE7100 during flow condensation in minichannels”
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Application of neural networks for identification of forcedness having effect on magnitude of turbine rotor vibration using pressure distribution in blade tip clearance.
PublicationW pracy sprawdzono, czy zastosowanie sieci neuronowych umożliwia identyfikację wymuszeń powstających w wyniku funkcjonowania maszyny jak i zależnych od jej stanu mechanicznego przy zastosowaniu rozkładu ciśnienia w uszczelnieniu nadbandażowym. Przeprowadzono pomiary rozkładu ciśnienia dla różnych warunków pracy, uwzględniając zmianę mimośrodu oraz zmianę skośnego ustawienia osi wirnika względem osi korpusu. Dokonano analiz przy...
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Wind Conditions in Urban Layout – Numerical and Experimental Research
PublicationThis paper presents research which compares the numerical and the experimental results for different cases of airflow around a few urban layouts. The study is concerned mostly with the analysis of parameters, such as pressure and velocity fields, which are essential in the building industry. Numerical simulations have been performed by the commercial software Fluent, with the use of a few different turbulence models, including...
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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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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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Action-reaction based synthesis of acoustic wavefield equations
PublicationThe analysis of acoustic fields is usually based on the well-known mathematics of second order partial differential equations called wave equations. The author explores the duality and symmetry of linear fluid mechanics and develops two distinct equations of acoustics on the basis of a causal approach to local small-scale phenomena. Wavefields that are solutions of these equations have different composition, the spherical pressure...
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Impact of surface skin temperature change on blood flow characteristics in palm
PublicationHeating a human palm during 3 minutes period causes changes in superficial skin temperature and leads to thermoregulation system response. The response time and level of flow characteristics change depend on the subject hand size and health of his vascular tree. A solution of Pennes bioheat propagation model was analyzed in order to see how much heat has to be transferred into the tissue to extort the observable reaction. The reflective...
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Wave energy attenuation in fields of colliding ice floes – Part 1: Discrete-element modelling of dissipation due to ice–water drag
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