Filters
total: 2708
filtered: 1678
displaying 1000 best results Help
Search results for: blood%20pressure
-
Influence of Gaps’ Geometry Change on Leakage Flow in Axial Piston Pumps
PublicationAxial piston pumps are the core elements of most medium and high-pressure hydraulic systems. High volumetric efficiency and high working pressures are the main advantages of this type of pumps. Therefore it is necessary to accurately calculate the leakage flow through the gaps to design efficient high-pressure pump. The main difficulty of such calculations is the fact, that the gaps change their geometry during pumping process....
-
Effects of Addictive Substances During Pregnancy and Infancy and Their Analysis in Biological Materials
PublicationThe use of addictive substances during pregnancy is a serious social problem, not only because of effects on the health of the woman and child, but also because drug or alcohol dependency it detracts from childcare and enhances the prospect of child neglect and family breakdown. Developing additive substance abuse treatment programs for pregnant women is socially important and can help ensure the health of babies, prevent subsequent...
-
Effect of Maximal Breath Hold Apnea on Pial Artery Pulsation and Subarachnoid Width in Human
PublicationLittle is known about intracranial pressure (ICP)-cerebral hemodynamic interplay during maximal breath-hold apnea. 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. Changes in sas-TQ correlate with ICP to a considerable extent, whereas cc-TQ reflects the functional...
-
Photolytic and Photocatalytic Recreational Water Treatment
PublicationDisinfection is one of the most important steps during recreational water treatment. Nevertheless, disinfection by-products are formed by conventional disinfectants, which pose several health threats. The concentration of disinfection by-products can be decreased by photolytic and photocatalytic treatment. Medium-pressure mercury lamp, UV-LEDs and solar irradiation were investigated and evaluated considering emitted wavelength,...
-
Raz jeszcze o obciążeniu hydrodynamicznym falochronu pionowościennego falą stojącą
PublicationPrzedstawienie istniejących modeli matematycznych opisujących rozkłady ciśnienia hydrodynamicznego na falochron pionowościenny w wyniku oddziaływania fali stojącej. Analiza nieciągłości ciśnienia. Jakościowe porównanie metod obliczeniowych dla wybranych warunków wodno-falowych.
-
Color-based Detection of Bleeding in Endoscopic Images
PublicationIn this paper a color descriptor designed for bleeding detection in endoscopic images is proposed. The development of the algorithm was carried out on a representative training set of 36 images of bleeding and 25 clear images. Another 38 bleeding and 26 normal images were used in the final stage as a test set. All of the considered images were extracted from separate endoscopic examinations. The experiments include color distribution...
-
Arterial cannula shape optimization by means of the rotational firefly algorithm
PublicationThe article presents global optimization results of arterial cannula shapes by means of the newly modified firefly algorithm. The search for the optimal arterial cannula shape is necessary in order to minimize losses and prepare the flow that leaves the circulatory support system of a ventricle (i.e. blood pump) before it reaches the heart. A modification of the standard firefly algorithm, the so-called rotational firefly algorithm,...
-
Analysis of MArkers of Exposure to Constituents of Environmental Tobacco Smoke (ETS)
PublicationTobacco smoke is a complex mixture of more than 4000 chemical compounds, many of which are harmful to human health. These compounds belong to various chemical classes, including amides, imides, lactams, carboxylic acids, aldehydes, ketones, alcohols, phenols, amines, hydrocarbons, ethers, and inorganic compounds. There are three types of tobacco smoke streams: the mainstream, the sidestream, and environmental tobacco smoke (ETS)....
-
Stress Detection of Children with Autism using Physiological Signals in Kaspar Robot-Based Intervention Studies
PublicationThis study aims to develop a stress detection system using the blood volume pulse (BVP) signals of children with Autism Spectrum Disorder (ASD) during robot-based interven- tion. This study presents the heart rate variability (HRV) analysis method to detect the stress, where HRV features are extracted from raw BVP signals recorded from an E4 wristband during interaction studies with the social robot Kaspar. Low frequency power...
-
Genetic and pharmacologic proteasome augmentation ameliorates Alzheimer’s-like pathology in mouse and fly APP overexpression models
PublicationThe proteasome has key roles in neuronal proteostasis, including the removal of misfolded and oxidized proteins, presynaptic protein turnover, and synaptic efficacy and plasticity. Proteasome dysfunction is a prominent feature of Alzheimer’s disease (AD). We show that prevention of proteasome dysfunction by genetic manipulation delays mortality, cell death, and cognitive deficits in fly and cell culture AD models. We developed...
-
Oxylipin profiling for clinical research: Current status and future perspectives
PublicationOxylipins are potent lipid mediators with increasing interest in clinical research. They are usually measured in systemic circulation and can provide a wealth of information regarding key biological processes such as inflammation, vascular tone, or blood coagulation. Although procedures still require harmonization to generate comparable oxylipin datasets, performing comprehensive profiling of circulating oxylipins in large studies...
-
Special techniques and future perspectives: Simultaneous macro- and micro-electrode recordings
PublicationThere are many approaches to studying the inner workings of the brain and its highly interconnected circuits. One can look at the global activity in different brain structures using non-invasive technologies like positron emission tomography (PET) or functional magnetic resonance imaging (fMRI), which measure physiological changes, e.g. in the glucose uptake or blood flow. These can be very effectively used to localize active patches...
-
Regulator przepływu
PublicationW artykule opisano konstrukcję i wyniki badań prototypu regulatora przepływu charakteryzującego się brakiem sprężyny. W regulatorze zawór różnicowy zastąpiono zaworem stosunku ciśnień. Charakterystyki przepływowe regulatora mają przebieg niezależny od obciążenia. Nastawa regulatora odbywa się poprzez obrót hydrostatycznie odciążonej tulei dławiącej, wewnątrz której umieszczony jest suwak główny i suwak pomocniczy zaworu stosunku...
-
TIME-AND-SPACE STRUCTURE OF FORCE-DRIVEN RIGID SPHEREWAVEFIELD
PublicationThis paper introduces a time-domain, causality-inspired description of a vector-source acoustic wavefield of arbitrary time evolution, where a sphere is a practical realisation of quasi-point contact surface without which a point force would not be able to exert an impact onto non-viscous fluid. At every space location, the resulting acoustic field is described by a pair of physical variables characterising the time evolution of...
-
Experimental examination and modification of chip suction system in circular sawing machine
PublicationThe article presents the results of experimental examination of the wood chip suction system in the existing sliding table saw before and after its modifi cation. The studies focused on the extraction hood of the mentioned system. The methodical experimental research of the pressure distribution inside the hood during wood chip removal for the selected rotational speed of saw blades of 3500 and 6000 min-1 with a diameter of 300...
-
Influence of water and mineral oil on the leaks in satellite motor commutation unit clearances
PublicationThe article describes the flow rates of mineral oil and water flowing, as working media, through the commutation unit of a hydraulic satellite motor. It is demonstrated that geometrical dimensions of commutation unit clearances change as a function of the machine shaft rotation angle. Methods for measuring the rate of this flow and the pressure in the working chamber are presented. The results of pressure measurements in the working...
-
Wyznaczenie obciążeń na poszycie okrętu wywołanych uderzeniem fal i uderzeniem w lód i ich wpływ na bezpieczeństwo okrętu
PublicationThe main problem is the vessels rather accurate determination of the hydrodynamic loads so-called hydroelasticity outside . This can be done by theoretical analysis , computer simulation or by experiment. This gives the hydrodynamic pressure distribution on the walls of the ship's hull and also on the walls of marine vessels .The most dangerous are the impact of extreme storm waves , the impact of the wharf and the impact zone...
-
Nuclear Co-generation: The Analysis of Technical Capabilities and Cost Estimates
PublicationThis paper presents a concept of the parallel connection of a nuclear power plant fitted to provide heat for district heating application, with the CHP and heat plants existing in the supply region, in this case with the heating systems of Wejherowo and Gdynia. Presented variant proposes to add heat to a nuclear power plant’s total output by supplying heat exchangers with the steam from bleeders of low pressure (LP) turbine stage...
-
Modal analysis of a fish-belly flap type of steel water gate
PublicationABSTRACT: The results of a modal analysis of the fish-belly flap type of steel water gate are presented in the paper. The analysis was conducted for a detailed numerical model of the structure using four-node quadrilateral shell elements. The study was focused on the examination of the influence of positioning of the flap gate and hydrostatic pressure of water on the eigenvalues and eigenmodes of the structure. The results of the study...
-
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...
-
Alternative convolution approach to friction in unsteady pipe flow
PublicationIn the paper some aspects of the unsteady friction in pipe flow expressed by the convolution are analyzed. This additional term introduced into the motion equation involves the accelerations of fluid occurring in the past and a weighting function. The essence of such approach is to assume the appropriate form of weighting function. However, until now no fully reliable formula for this function has been found. To avoid some inconveniences...
-
Selected aspects of performance of organic Rankine cycles incorporated into bioenergy with carbon capture and storage using gasification of sewage sludge
PublicationThe study aims to investigate the application of the Organic Rankine Cycle (ORC) in the bioenergy with carbon capture and storage (BECCS) using gasification of sewage sludge. The tool used in the investigation is the Aspen Plus software with REFPROP property methods for calculating fluid properties. The reason for this study is that a detailed analysis of the proposed BECCS process flow diagram indicates that a certain amount of...
-
Analysis of start energy of Stirling engine type alpha
PublicationThe Stirling engine type alpha is composed of two cylinders (expansion space E and compression space C), regenerator that forms the space between the cylinders and the buffer space (under the pistons). Before the start-up and as a result of long-term operation, the average pressure in the working space (above the pistons) and in the buffer space is the same. However, in the initial phase of operation, the average pressure in the...
-
Analiza porównawcza procesów tłumienia i wygładzania fali ciśnienia w trakcie nieustalonego przepływu w rurociągach wykonanych z różnych materiałów.
PublicationUderzenie hydrauliczne jest uważane za jeden z najważniejszych problemów nieustalonego przepływu w przewodach, dlatego nadal stanowi obiekt badań wielu naukowców. To zagadnienie może być badane na dwóch poziomach: praktycznym i teoretycznym. W artykule zaprezentowane zostały wyniki badań doświadczalnych przeprowadzonych na stanowisku pomiarowym nieustalonego przepływu, funkcjonującym w Laboratorium Hydraulicznym Wydziału Inżynierii...
-
Experimental investigation of forced convection of water-Al2O3 nanofluids inside horizontal tubes,
PublicationIn this paper, forced convection of water–Al2O3 nanofluids inside horizontal copper tube is studied experimentally. Experiments were conducted for three, i.e. 0.1%, 1% and 5% nanoparticle mass concentrations under transition and turbulent flow regimes. Average heat transfer coefficients and pressure drop values were determined and compared to distilled water. Enhancement of heat transfer for lower nanoparticle concentration and...
-
Towards Understanding of Mechanics of Hernia Managed by Synthetic Mesh in Laparoscopic Operation: A Single Case Study
PublicationIn this paper a research towards understanding of mechanics of ventral hernia operated with the use of Physiomesh Open image in new window implant and SecureStrap Open image in new window staples is described. Experimental and numerical studies are conducted for that purpose. Experimental works cover uni-axial tension tests of the implant samples and of the implant-staples-tissue system. Also experiments on implant-staples-tissue...
-
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...
-
IR-THERMAL IMAGING IN CARDIOSURGERY
PublicationA method for monitoring the state of the myocardium during cardiosurgical interventions based on thermal IR imaging is presented. These methods called Static Thermography and Active Dynamic Thermography (ADT) uses information about distribution of temperature on the surface and an external excitation source to induce thermal transient processes in a tested object. Recording time series of thermograms allows to calculate parametric...
-
Hyaluronic acid/tannic acid films for wound healing application
PublicationIn this study, thin films based on hyaluronic acid (HA) with tannic acid (TA) were investigated in three different weight ratios (80HA/20TA, 50HA/50TA, 20HA/80TA) for their application as materials for wound healing. Surface free energy, as well as their roughness, mechanical properties, water vapor permeability rate, and antioxidant activity were determined. Moreover, their compatibility with blood and osteoblast cells was investigated....
-
Genetic and pharmacologic proteasome augmentation ameliorates Alzheimer’s-like pathology in mouse and fly APP overexpression models
PublicationThe proteasome has key roles in neuronal proteostasis, including the removal of misfolded and oxidized proteins, presynaptic protein turnover, and synaptic efficacy and plasticity. Proteasome dysfunction is a prominent feature of Alzheimer’s disease (AD). We show that prevention of proteasome dysfunction by genetic manipulation delays mortality, cell death, and cognitive deficits in fly and cell culture AD models. We developed...
-
A new diagnostic IR-thermal imaging method for evaluation of cardiosurgery procedures
PublicationTwo methods for monitoring the state of the myocardium during cardiosurgical interventions based on thermal IR imaging are presented below. These methods, called static thermography and active dynamic thermography (ADT), use information about the distribution of temperature on the surface, and an external excitation source to induce thermal transient processes in a tested object. Recording the time series of thermograms allows...
-
ANALYSIS OF THE IMPACT OF MASS FLOW EXTRACTION ON THE CHANGE OF PARAMETERS IN A LABYRINTH SEAL USING THE STODOLA METHOD
PublicationLabyrinth seals are an important element of a steam turbine set design. The use of diagnostic extraction makes it possible to control the operation of a seal by providing information on the thermodynamic parameters along the length of the seal. Diagnostic extraction has a considerable impact on the change of the parameters, the amount of the extracted mass. This article describes the dependence of pressure in the clearance downstream...
-
ANALYSIS OF THE IMPACT OF MASS FLOW EXTRACTION ON THE CHANGE OF PARAMETERS IN A LABYRINTH SEAL USING THE STODOLA METHOD
PublicationLabyrinth seals are an important element of a steam turbine set design. The use of diagnostic extraction makes it possible to control the operation of a seal by providing information on the thermodynamic parameters along the length of the seal. Diagnostic extraction has a considerable impact on the change of the parameters, the amount of the extracted mass. This article describes the dependence of pressure in the clearance downstream...
-
Lax-Wendroff and McCormack Schemes for Numerical Simulation of Unsteady Gradually and Rapidly Varied Open Channel Flow
PublicationTwo explicit schemes of the finite difference method are presented and analyzed in the paper. The applicability of the Lax-Wendroff and McCormack schemes for modeling unsteady rapidly and gradually varied open channel flow is investigated. For simulation of the transcritical flow the original and improved McCormack scheme is used. The schemes are used for numerical solution of one dimensional Saint-Venant equations describing free...
-
The consequences of applying a new Polish Water Law Act for protection against urban flooding
PublicationPrevious legal regulations did not create conditions for a comprehensive solution to the problems of the urban melioration complex. For over 20 years, urban flooding caused by atmospheric precipitation has been systematically recurring in Poland. The article was elaborated on the experience resulting from the 2001 and 2016 floods in Gdansk (Poland). The newly adopted Water Law Act creates a foundation for a systemic solution...
-
Flow boiling of R1233zd(E) in a 3 mm vertical tube at moderate and high reduced pressures
PublicationThe results of flow boiling of R1233zd(E) in a 3 mm vertical stainless steel tube are presented at moderate and high saturation temperatures. Integral flow characteristics in the form of pressure drop and heat transfer coefficient are discussed for saturation temperatures ranging from 115 to 145 °C (corresponding reduced pressures from 0.2 to 0.7), mass velocity of 800 kg/m2s and heat flux of 20 kW/m2. All of the obtained heat...
-
Kompensacja skoków ciśnienia w pompie tłoczkowej o zmiennej wydajności z rozrządem krzywkowym
PublicationPrzedmiotem rozprawy doktorskiej jest opis matematyczny, badania i symulacja mechanizmu kompensacji skoków ciśnienia w pompie tłoczkowej z rozrządem krzywkowym typu PWK. W rozprawie przedstawiono istniejące rozwiązania konstrukcyjne pomp tłokowych, kładąc szczególny nacisk na przedstawienie stosowanych w nich mechanizmów rozrządu i kompensacji skoków ciśnienia. Ponadto szczegółowo opisano budowę i zasadę działania pompy PWK będącej...
-
Running characteristics of aerodynamic bearing with self-lifting capability at low rotational speed
PublicationAn aerodynamic journal bearing that is capable of self-generating squeeze-film pressure is presented and its dynamic characteristics investigated numerically and experimentally. A numerical method based on a time marching static model was applied to assess the orbit trajectory path of the rotor upon a perturbation. Experimental results were obtained to validate the effect of the self- generated squeeze-film pressure on the stability...
-
Noise related to gas bottles explosions
PublicationModern industrialized world is in a never ending danger of accidents and catastrophes of technical nature. Some of them may involve fires and explosions of gas storage bottles or containers. Technical University of Gdansk, Poland performed numerous tests where bottles containing acetylene, oxygen, hydrogen, CO2, LPG, LNG or CNG were blown due to excessive temperature caused by fire. Although those experiments were not focused on...
-
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...
-
Low-energy interactions related to atmospheric and extreme conditions
PublicationThis Topical Issue, entitled “Low-Energy Interactions Related to Atmospheric and Extreme Conditions”, showcases a collection of eighteen articles that reported recent theoretical and experimental findings pertaining to the following topics: – low-energy interactions of charged particles (electrons [1–7], protons [8], positrons [9]), and photons [10] with atoms and molecules of biological [1–4,7,8], astrochemical [10], industrial,...
-
Application in circular sawing machines of the experimental results of investigations of the chip removing system operation
PublicationThe experimental results of the chip removing system operation are presented. The main aim of them was to optimize suction system of the panel saw Fx3 and its follower Fx550. The attention was focused on the upper casing, which was the part of removing system. Within the framework of the work a systematic experimental study of pressure distribution in the casing during operation of the selected rotational speed of saw blade with...
-
Experimental investigation of forced convection of water/EGAl2O3 nanofluids inside horizontal tube
PublicationIn this paper, forced convection of water/EG-Al2O3 nanofluids inside horizontal stainless steel tube is studied experimentally. As base fluid served water/EG mixture of two ratios (60:50 and 50:50). Nanoparticle mass concentrations was 0.1% or and 1%. Transition and turbulent flow regimes were tested. Average heat transfer coefficient and pressure drop values were determined for nanofluids and compared to base fluids. Deterioration...
-
Regional resting state perfusion variability and delayed cerebrovascular uniform reactivity in subjects with chronic carotid artery stenosis
PublicationThe aim of this study was to assess regional perfusion at baseline and regional cerebrovascular resistance (CVR) to delayed acetazolamide challenge in subjects with chronic carotid artery stenosis.Sixteen patients (ten males) aged 70.94±7.71 with carotid artery stenosis ≥90% on the ipsilateral side and ≤50% on the contralateral side were enrolled into the study. In all patients, two computed tomography perfusion examinations were...
-
SafeCity – a GIS-based tool profiled for supporting decision making in urban development and infrastructure protection
PublicationThis paper presents a system for analysis of municipal Critical Infrastructures, which offers integrated tools for target analysis, hazard scenario simulations and spatial analysis within a remotely accessible Web-based Geographic Information System. The system has been applied to research conducted in the city of Gdansk with the aid of blast attack, chemical leakage and flood hazard scenarios, as well as a spatial density algorithm,...
-
The new concept of capillary forces aided evaporator for application in domestic organic rankine cycle
PublicationThis paper presents studies on the possibility of applying capillary forces induced in the porous structure to a modern design of evaporator. The potential application of such heat exchanger is for example an evaporator of the domestic micro combined heat and power (CHP) unit. One of the problems in the micro-CHP is excessive demand for pumping power. The proposed design helps in overcoming that issue. In the evaporator outlined...
-
Comparative in vitro research of the Human Aortic Bioprosthesis
PublicationE valuate of the usefulness and reliability of structures based on the analysis of recorded parameters determining the flow through the Human Aortic Bioprosthesis (HAB) have been dealt with. By flow parameters changes determining the performance environment of prosthesis analyzed change of the motion dynamics of the valve leaflets as a function of pressure, thereby determining the degree of alignment of the prosthesis to the performance...
-
Monitoring of volatile organic compounds (VOCs) in atmospheric air. Part I. On-line gas analyzers
PublicationThe paper reviews the subject literature concerning the analytical instruments routinely used for monitoring volatile organic compounds in atmospheric air. The analyzers are classified as stationary or mobile according to their ease of transport. Stationary DOAS (Differential Optical Absorption Spectroscopy) analyzer is characterized, as are MIMS (Membrane Introduction Mass Spectrometry), MESI (Membrane Extraction with Sorbent...
-
Properties of Nasicon-based CO2 sensors with Bi8Nb2O17 reference electrode
PublicationPotentiometric CO2 sensors based on Nasicon (Na+ conductor, Na3Zr2Si2PO12) electrolyte, Bi8Nb2O17/Pt reference electrode and different sensing electrodes have been prepared. Besides the sensing electrode material, sensors differ from each other in the reference electrode preparation technique. The main aim of this study is to investigate sensor construction and electrode fabrication process influence on sensor properties. The optimal...
-
A comparative performance assessment of a hydrodynamic journal bearing lubricated with oil and magnetorheological fluid
PublicationThis work presents the investigation results of a journal bearing lubricated with magnetorheological fluid that is activated by a local constant magnetic field to vary both the local flow resistance and pressure. The bearing performance is assessed via Finite Element Modelling (FEM) and results are corroborated by experiments. The FEM model uses the Bingham model to describe the fluid film. A dedicated test rig is used to assess...