Search
Filters
total: 3131
-
Catalog
displaying 1000 best results Help
Search results for: CFD, BLOOD FLOW
-
COVID-19 severity forecast based on machine learning and complete blood count data
PublicationProper triage of COVID-19 patients is a key factor in eective case management, especially with limited and insucient resources. In this paper, we propose a machine-aided diagnostic system to predict how badly a patient with COVID-19 will develop disease. The prognosis of this type is based on the parameters of commonly used complete blood count tests, which makes it possible to obtain data from a wide range of patients.We chose...
-
Safety assessment of ships in damaged conditions by the risk-based method. Assessment of damaged ship performance using the CFD modeling
PublicationW pracy przedstawiono aktualny stan badań w zakresie oceny bezpieczeństwa statków w stanie uszkodzonym. Przedstawiono wybrane elementy metody oceny bezpieczeństwa statków w stanie uszkodzonym opartej na analizie ryzyka. Przedstawiono istotę oceny zachowania się statku w stanie uszkodzonym i oceny ryzyka w proponowanej metodzie. Przedstawiono elementy modelowania zachowania się statku w stanie uszkodzonym przy użyciu metody numerycznej...
-
Application of a cellular automaton to simulations of granular flow in silos
PublicationA cellular automaton based on a gas model of hydrodynamics was used to calculate the kinematics of non-cohesive granular materials during confined flow in a mass flow and funnel flow model silo. In the model, collisions of particles were taken into account during granular flow. In addition, a simplified automaton was used wherein granular flow was assumed as an upward propagation of holes through a lattice composed of cells representing...
-
CFD COUPLING OF VOF MODEL WITH ARRHENIUS EQUATION FOR ANALYSIS OF LASER-INDUCED THERMAL DEACTIVATION OF E. COLI
PublicationUnderstanding bacterial deactivation at the micro-scale, particularly with E. coli, is crucial for advancing microbiology and has promising applications in biomedical research. In this research contribution, we investigate the thermal inactivation of E. coli bacteria using gold nanoparticles irradiated by a green 1-W laser within a microfluidic chamber. The microfluidic device comprises a fluidic chamber filled with a thin film...
-
NUMERICAL SIMULATIONS OF GAP FLOW ABOVE ROTATING DISK
PublicationA rotating disk can be considered a basic configuration for the investigati ons of the impact of various conditions on the flow through the clearance between the s hrouded turbine blade and the casing. Numerical calculations using Fine/Turbo Numeca were conducted to examine the influence of the rotational velocity and the pressure differ ence across the disk on the flow conditions, especially the mass flow through the clearance....
-
Dariusz Mikielewicz prof. dr hab. inż.
PeopleProfessor Dariusz Mikielewicz – born on February 6, 1967. in Gdansk. Here in 1974 he enrolled first to the Elementary School No. 17, and then in the Grammar School No. 5, named after Stefan Żeromski in Gdansk-Oliwa. After graduating from the Secondary School, with honors, in 1985 he successfully passed the entrance exams to the Faculty of Mechanical Engineering of Technical University of Gdansk, where he graduated with a very good...
-
Flow boiling intensification in minichannels by means of mechanical flow turbulising inserts
PublicationThe work presents the results of experimental investigation on heat transfer in minichannels. Refrigerant R123 was used as a test fluid. Single vertical silver tubes of 380 mm length and 2.3 mm diameter were examined with two variants of turbulising inserts. A wide range of parameters was considered, namely mass flux G=534-3011 kg/(m2s), heat flux qw=28.5-68.4 kW/m2, saturation temperature Tsat=23-86 stC and the full range of vapour...
-
Experimental Verification of Storm Sewer Transient Flow Simulation
PublicationThe paper focuses mainly on laboratory investigations of transient and transcritical flow in a single pipe of a sewer system. The aim of this paper is to present a comparison between pressure values calculated by an improved McCormack scheme and those measured at the hydraulic laboratory of the Gdansk University of Technology, which were observed inside a pipe in an experiment for water flow with pressurization. The analysis proves...
-
Determination of 3,4-methylenedioxy-α-pyrrolidinobutiophenone (MDPB) in blood. A case report
PublicationSynthetic drugs, known as ‘‘legal highs’’, are still very popular on black market. The determination of their composition are required in courts of law and also to understand what potential users may be subjected to. The interest of new cathinones, e.g. MDPBP, is in view of psychoactive effects that they cause and that, in many cases, they are not controlled by law. The case outlined here concerns 19 years-old man, who was found...
-
Response of a New Low-Coherence Fabry-Perot Sensor to Hematocrit Levels in Human Blood
PublicationIn this paper, a low-coherence Fabry-Perot sensor with a spectrally measured signal processing response to the refractive index of liquids is presented. Optical fiber sensors are potentially capable of continuous measuring hematocrit levels in blood. Low-coherence Fabry-Perot interferometric sensors offer a robust solution, where information about the measurand is encoded in the full spectrum of light reflected from the sensing...
-
Application of gas chromatography–tandem mass spectrometry for the determination of amphetamine-type stimulants in blood and urine
PublicationAmphetamine, methamphetamine, phentermine, 3,4-methylenedioxyamphetamine (MDA), 3,4-methylenedioxymethamphetamine (MDMA), and 3,4-methylenedioxy-N-ethylamphetamine (MDEA) are the most popular amphetamine-type stimulants. The use of these substances is a serious societal problem worldwide. In this study, a method based on gas chromatography-tandem mass spectrometry (GC-MS/MS) with simple and rapid liquid-liquid extraction (LLE)...
-
QoS Extensions for Flow-Awareness Networks
PublicationThe paper contains a description and research results of the proposal for distributed QoS extensions for Flow-Based Networking. These QoS extensions let the network accept or reject flows based on current network load and QoS promises for each of the flows. Proposed solution consists of two distributed components, each of them performing in every node, measurement system and access control. The solution could be applied in any...
-
Gender-Related Differences in Trimethylamine and Oxidative Blood Biomarkers in Cardiovascular Disease Patients
PublicationGender differences in the burden of cardiovascular disease (CVD) have been observed worldwide. In this study, plasmatic levels of trimethylamine (TMA) and blood oxidative biomarkers have been evaluated in 358 men (89 controls and 269 CVD patients) and 189 women (64 control and 125 CVD patients). The fluorescence technique was applied to determine erythrocyte membrane fluidity using 1,6-diphenyl-1,3,5-hexatriene (DPH) and Laurdan,...
-
Longitudinal tracking of muscle sympathetic nerve activity and its relationship with blood pressure in subjects with prehypertension
Publication -
Daytime, home and office blood pressures in treated hypertensive patients according to accretion of cardiovascular risk
Publication -
Pawlak's flow graph extensions for video surveillance systems
PublicationThe idea of the Pawlak's flow graphs is applicable to many problems in various fields related to decision algorithms or data mining. The flow graphs can be used also in the video surveillance systems. Especially in distributed multi-camera systems which are problematic to be handled by human operators because of their limited perception. In such systems automated video analysis needs to be implemented. Important part of this analysis...
-
Comparative study of flow condensation in conventional and small diameter tubes
PublicationFlow boiling and flow condensation are often regarded as two opposite or symetrical phenomena. Their description however with a single correlation has yet to be suggested.In the case of flow boiling in minichannels there is mostly encountered the annular flow structure, where the buble generetion is not present. Similar picture holds for the case of inside tube condensation, where annular flow structure predominates. In such case...
-
Flow maldistribution and its mitigation in mini heat exchangers
PublicationIn the present paper, a detailed numerical investigation has been carried out to analyze the flow maldistribution in 50 parallel 1 mm x 1 mm rectangular minichannels and 1 mm depth minigap section with rectangular, trapezoidal, triangular or concave mani-folds in Z-type flow configuration (16 different cases). The working medium was ethanol and the mass flow rate was 5×10-4 kg/s. Both sections was heated from the bottom side. Heat...
-
The equivariant spectral flow and bifurcation of periodic solutions of Hamiltonian systems
PublicationWe define a spectral flow for paths of selfadjoint Fredholm operators that are equivariant under the orthogonal action of a compact Lie group as an element of the representation ring of the latter. This G-equivariant spectral flow shares all common properties of the integer valued classical spectral flow, and it can be non-trivial even if the classical spectral flow vanishes. Our main theorem uses the G-equivariant spectral flow...
-
Hydraulic fracturing process in rocks – small-scale simulations with a novel fully coupled DEM/CFD-based thermo-hydro-mechanical approach
PublicationW artykule przedstawiono dwuwymiarową (2D) symulację numeryczną szczelinowania hydraulicznego w małej skali przeprowadzoną w próbkach skał posiadających pojedynczą szczelinę wtryskową. Wykorzystano unikalny model termo-hydro-mechaniczny (THM) w skali porów oparty na DEM/CFD do symulacji dwufazowego laminarnego przepływu płynu (wody i gazu) z przenoszeniem ciepła w nienasyconych materiałach porowatych o niskiej porowatości. Korzystając...
-
Long-Term Stability of Benzodiazepines and Z-Hypnotic Drugs in Blood Samples Stored at Varying Temperatures
PublicationBenzodiazepines (BZDs) and Z-drugs are among the most commonly prescribed pharmaceuticals in the world and are considered standard care for various mental illnesses and for treatment of sleeping and anxiety disorders, alcohol withdrawal, muscle spasms and epilepsy. Some BZDs are not allowed as pharmaceuticals in many countries, and they are used as "designer benzodiazepines" (DBZDs). All these compounds are typically screened in...
-
Flow of liquid in flat gaps of the satellite motor working mechanism
PublicationThe article describes the methodology and results of investigations of the flow of oil and HFA-E emulsion in flat gaps of the working mechanism of a satellite motor. The flow of liquid in those gaps is turbulent and not fully developed. The article presents two methods of modelling this flow. Method I makes use of the Darcy-Weisbach formula, while Method II bases on the assumption that in the variable-length gaps the flow is turbulent...
-
CFD modeling of a diesel evaporator used in fuel cell systems
Publication -
CFD analysis of jet flows ejected from different nozzles
Publication -
Flows in turbine blade seals: CFD calculations versus experiment
PublicationPrzedstawiono wyniki numerycznej analizy przepływu w uszczelnieniu nadbandażowym stopnia turbinowego. Rezultaty obliczeń porównano z danymi doświadczalnymi. Eksperymenty przeprowadzono na modelowej turbinie powietrznej przy różnych częstościach obrotów wału i różnym obciążeniu turbiny.
-
Influence of the air phase on water flow in dikes
PublicationNumerical models are often used to describe flow and deformation processes occurring in dikes during flood events. Modeling of such phenomena is a challenging task, due to the complexity of the system, consisting of three material phases: soil skeleton, pore water and pore air. Additional difficulties are transient loading caused by variable in time water levels, heterogeneity of the soil or air...
-
Selected studies of flow maldistribution in a minichannel plate heat exchanger
PublicationAnalysis of the state of-the-art in research of minichannel heat exchangers, especially on the topic of flow maldistribution in multiple channels, has been accomplished. Studies on minichannel plate heat exchanger with 51 parallel minichannels with four hydraulic diameters, i.e., 461 μm, 574 μm, 667 μm, and 750 μm have been presented. Flow at the instance of filling the microchannel with water at low flow rates has been visualized. The...
-
Experimental study on the seepage flow through the ice jam
PublicationIn light of the observed climate change, there is a need for better understanding of river ice processes for managing water resources in the cold regions. Ice jams produce significant resistance which may cause rise of water level and flooding. The jam resistance is only referred to the roughness of its underside, and this approach lead to exceptional roughness coefficients which has no physical explanation. Number of evidences...
-
Pressure drop of HFE7000 and HFE7100 during flow condensation in minichannels
PublicationAttention is focused on the issues of flow resistance and pressure drop of perspective refrigeration fluids during condensation in the two-phase flow in minichannels. The case of the flow through a cylindrical single channel of 2.3 mm inner diameter was carefully analyzed. Pressure drop tests have been performed in diabatic flow conditions. The effect of heat flux, mass flux, vapour quality and saturation temperature on the two-phase...
-
Increased inspiratory resistance affects the dynamic relationship between blood pressure changes and subarachnoid space width oscillations
PublicationBackground and objective Respiration is known to affect cerebrospinal fluid (CSF) movement. We hypothesised that increased inspiratory resistance would affect the dynamic relationship between blood pressure (BP) changes and subarachnoid space width (SAS) oscillations. Methods Experiments were performed in a group of 20 healthy volunteers undergoing controlled intermittent Mueller Manoeuvres (the key characteristic of the procedure...
-
PROPERTIES OF ONE DIMENSIONAL OPEN-CHANNEL STEADY FLOW EQUATIONS
PublicationIn this paper properties of discrete forms of one dimensional steady gradually varied flow equations are discussed. Such forms of flow equations are obtained as a result of approximation of their differential forms, which is required to solve them numerically. For such purpose explicit or implicit numerical approximation schemes for ordinary differential equations can be applied. It turns out that dependently on the chosen approximation...
-
DISTRIBUTION OF FLOWS IN A CHANNEL NETWORK UNDER STEADY FLOW CONDITIONS
PublicationThe article presents an algorithm for calculating the distribution of flow in a junction of open channel network under steady flow conditions. The article presents a simplified calculation algorithm used to estimate the distribution of flow in a network of channels under steady flow conditions. The presented algorithm is based on the continuity equation and a simplified energy equation. To describe the relationship between the...
-
Free-surface elevation in open vortex flow controls
PublicationRotational form of fluid motion is complex, but very important in science and technology. The paper is devoted to the hydraulic mechanism of flow in open vortex flow controls, or regulators. The velocity field was described by the kinematic model, and intensity of rotation - by means of the energy balance between the input and dissipation. In consequence some algebraic expresions were obtained, which can be useful in approximated...
-
Supine blood pressure normalised by daytime series values is independently associated with ischaemic wake-up stroke
Publication -
Blood pressure lowering effect of renal sympathetic denervation or placebo? - building expectations for Symplicity-HTN 3
Publication -
Ambulatory Blood Pressure Adds to Explaining Benefits of AT‐1 Receptor Blockade in the Treatment of Left Ventricular Hypertrophy
Publication -
High-normal blood pressure is associated with increased resting sympathetic activity but normal responses to stress tests
Publication -
Blood concentrations of a new psychoactive substance 4-chloromethcathinone (4-CMC) determined in 15 forensic cases
PublicationPurpose: The 4-chloromethcathinone (4-CMC) is a synthetic derivative of cathinone and belongs to new psychoactive substances. Neither data on the effects of 4-CMC on the human body, nor on nontoxic, toxic and lethal concentrations in biological materials have been published in the literature. This paper describes the results of an analysis of the blood concentrations of 4-CMC determined in 15 forensic cases related to nonfatal...
-
The logistics streamlining of the material flow at the production company
PublicationThe main practical problem in the Logistics Department at the company is overstaffing in the unit responsible for the flow of materials. Carried out by the authors of the article, some detailed research on the process analysis in the discussed company indicates that the main cause of such a situation is related to an increase in the amount of transported material and a lack of redesigning the material flow in...
-
Coupled DEM/CFD analysis of impact of free water on the static and dynamic response of concrete in tension regime
PublicationW tym artykule zbadano numerycznie quasi-statyczne i dynamiczne zachowanie częściowo nasyconego płynem betonu w warunkach dwuwymiarowego (2D) jednoosiowego rozciągania w mezoskali. Obliczono, jaki wpływ ma zawartość wolnego płynu porowego (gazu i wody) na proces pękania i wytrzymałość betonu w rozciąganiu. Do symulacji zachowania betonu całkowicie i częściowo nasyconego płynem w warunkach quasi-statycznych i dynamicznych wykorzystano...
-
Steady magnetohydrodynamic flow in a diverging channel with suction or blowing
PublicationAn analysis is made of steady two-dimensional divergent flow of an electrically conducting incompressible viscous fluid in a channel formed by two non-parallel walls, the flow being caused by a source of fluid volume at the intersection of the walls. The fluid is permeated by a magnetic field produced by an electric current along the line of intersection of the channel walls. The walls are porous and subjected to either suction...
-
Comparative study of flow condensation in conventional and small diameter tubes
PublicationFlow boiling and flow condensation are often regarded as two opposite or symmetrical phenomena, however their description with a single correlation has yet to be suggested. In the case of flow boiling in minichannels there is mostly encountered the annular flow structure, where the bubble generation is not present. Similar picture holds for the case of inside tube condensation, where annular flow structure predominates. In such...
-
Recent progress in experimental studies of electrohydrodynamic flow in electrostatic precipitators
PublicationMany experimental, theoretical and numerical works were devoted to the electrohydrodynamic (EHD) flow generated in electrostatic precipitators (EPSs). The generally accepted conclusion from these studies is that the EHD flow plays an important role in the particle collection in ESPs. However, despite of the recent fast progress in numerical simulation and experimental techniques used in the ESPs studies many problems related to...
-
Application of GC-MS/MS technique for the determination of benzodiazepines in blood samples
PublicationAbstract Benzodiazepines (BZD) are widely used as pharmaceuticals in medicine. However, due to psychostimulatory effect of BZD, in the last decade, they are more and more often used as drugs of abuse. These compounds produce similar effects to classical illicit drugs and are sold as “legal” alternatives to them as new psychoactive substances (NPS). Currently new BZD, named designer benzodiazepines (DBZD), are synthesized each year...
-
Two-phase flow structure assessment based on dynamic image analysis
Publication -
Description of the silo flow and bulk solid pulsations detection using ECT
PublicationW artykule przedstawiono wyniki zastosowania tomografii pojemnościowej do analizy pulsacji występujących w bezkohezyjnym materiale sypkim podczas opróżniania silosu cylindrycznego. Przeanalizowano wpływ parametrów zmiennych (zagęszczenia początkowego, szorstkości ściany, prędkości opróżniania) na wielkość dynamicznych pulsacji)
-
A System for Cooling Electronic Elements with EHD Coolant Flow
PublicationA system for cooling electronic components where the liquid coolant flow is forced with ion-drag type EHD micropumps was tested.
-
Graphene field-effect transistor application for flow sensing
PublicationMicroflow sensors offer great potential for applications in microfluidics and lab-on-a-chip systems. However, thermal-based sensors, which are commonly used in modern flow sensing technology, are mainly made of materials with positive temperature coefficients (PTC) and suffer from a self-heating effect and slow response time. Therefore, the design of novel devices and careful selection of materials are required to improve the overall...
-
A numerical and experimental analysis of multi-hole orifice in turbulent flow
PublicationIn this research study, the comprehensive metrological analysis is investigated for a 4-hole orifice with module m = 0.25 installed in the pipeline with an internal diameter of 50 mm. A detailed numerical simulation was performed for the turbulence models: k-ε-realizable and k-ω-BSL. The novelties of the research include model validation by comparing the results of numerical studies with the experiment conducted in the area of...
-
The vortex flow caused by sound in a bubbly liquid
PublicationGeneration of vorticity in the field of intense sound in a bubbly liquid in the free half-space is considered. The reasons for generation of vorticity are nonlinearity, diffraction, and dispersion. Acoustic streaming differs from that in a Newtonian fluid. Under some conditions, the vortex flow changes its direction. Conclusions concern streaming induced by a harmonic or an impulse Gaussian beam.