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Wyniki wyszukiwania dla: axial blood pump
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Diamond-based protective layer for optical biosensors
PublikacjaOptical biosensors have become a powerful alternative to the conventional ways of measurement owing to their great properties, such as high sensitivity, high dynamic range, cost effectiveness and small size. Choice of an optical biosensor's materials is an important factor and impacts the quality of the obtained spectra. Examined biological objects are placed on a cover layer which may react with samples in a chemical, biological...
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Thin-walled cross section shape influence on steel member resistance.
PublikacjaThis work describes why trending thin-walled technology is achieving popularity in steel construction sector. A purpose of this article is to present the influence of the cold-formed element cross-section shape on an axial compression and a bending moment resistance. The authors have considered four different shapes assuming constant section area and thickness. Calculations were based on three different steel grades taking into...
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HYDROSTATIC THRUST BEARING WITH REDUCED POWER LOSSES
PublikacjaIn many cases in rotating machinery, axial load is carried by tilting pad thrust bearings which have been developed since the beginning of 20th century. For high reliability and simplicity, most commonly the bearings are bath lubricated. In the times of sustainable development, however, minimization of friction losses becomes an important criterion for machinery assessment, and a strategic goal of their development. Performed calculations,...
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Stiffness change of abdominal prosthesis Optomesh™ under cyclic loading
PublikacjaAbdominal prostheses are used in humans for abdominal wall strengthening or reconstruction. From the mechanical point of view they are membranes, so their basic mechanical property is tensile stiffness. This property is experimentally identified for a selected implant, OptomeshTM. The obtained results are described herein. Uni-axial simple and cyclic tension tests are a basis for the analysis. Both kinds of tests allowed to distinguish...
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Początek Gdyńskiego Systemu Wodociągowego Planowanie i budowa lokalnego układu wodociągowego na Kępie Oksywskiej (1929 – 1932. Część II.
PublikacjaUdokumentowanie procesu inwestycyjnego przekształcenia wodociągu wiejskiego w miejski układ wodociągowy na podstawie analizy materiałów źródłowych. Ustalenie hydrogeologicznych uwarunkowań decyzji o lokalizacji ujęcia wody „Oksywie”. Identyfikacja parametrów konstrukcyjnych i kosztów budowy trzech budynków na ujęciu wody: mieszkalnego, stacji pomp i odżelaziania wody. Odtworzenie przebiegu budowy struktury sieci wodociągowej w...
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EM-Driven Size Reduction and Multi-Criterial Optimization of Broadband Circularly-Polarized Antennas Using Pareto Front Traversing and Design Extrapolation
PublikacjaMaintaining small size has become an important consideration in the design of contemporary antenna structures. In the case of broadband circularly polarized (CP) antennas, miniaturization is a challenging process due to the necessity of simultaneous handling of electrical and field properties (reflection, axial ratio, gain), as well as ensuring sufficient frequency range of operation, especially at the lower edge of the antenna...
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Analytical procedures for determination of cocaine and its metabolites in biological samples
PublikacjaThe dangerous effects and increased usage of illicit drugs have inspired the development of analytical methodologies. We based our review of analytical procedures for determination of cocaine (COC) and its metabolites on literature from the past two decades. Our main aim was to compare the capabilities of different analytical techniques. The diversity of matrices from which COC is determined (e.g., blood, hair, saliva, plasma,...
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Thermal sequences database of the skin flaps in breast reconstruction and burns
PublikacjaThis paper presents a database of Active Dynamic Thermography (ADT) thermal sequences gathered throughout 6 year study on ADT application in skin flap blood perfusion monitoring and burn wounds diagnosis. For skin flap monitoring the database comprises of data collected during three different breast reconstruction procedures. The patients were monitored pre, intra and post surgically within 90 days period. The sequences were used...
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Stress Detection of Children With ASD Using Physiological Signals
PublikacjaThis paper proposes a physiological signal-based stress detection approach for children with autism spectrum disorder (ASD) to be used in social and assistive robot inter- vention. Electrodermal activity (EDA) and blood volume pulse (BVP) signals are collected with an E4 smart wristband from children with ASD in different countries. The peak count and signal amplitude features are derived from EDA signal and used in order to detect...
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Thermal sequences database of the skin flaps in breast reconstruction and burns
PublikacjaThis paper presents a database of Active Dynamic Thermography (ADT) thermal sequences gathered throughout 6 year study on ADT application in skin flap blood perfusion monitoring and burn wounds diagnosis. For skin flap monitoring the database comprises of data collected during three different breast reconstruction procedures. The patients were monitored pre, intra and post surgically within 90 days period. The sequences were used...
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Domestic ORC micro-CHP combined with a commercial gas boiler
PublikacjaThe chapter presents the results of experimental studies conducted during the launch of the first in Poland demonstration prototype of the micro ORC coupled to a domestic gas boiler. The accomplished studies indicated the possibility for the ORC module to work with such boiler (autonomous source of heat) with a prototype single-stage axial micro turbine as the expansion machine. Confirmation of that fact has been delineated in...
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A Review: Structural Shape and Stress Control Techniques and their Applications
PublikacjaThis review article presents prior studies on controlling shape and stress in flexible structures. The study offers a comprehensive survey of literature concerning the adjustment and regulation of shape, stress, or both in structures and emphasizes such control’s importance. The control of systems is classified into three primary classes: nodal movement control, axial force control, and controlling the two classes concurrently....
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OPTIMIZATION OF THE LAST STAGE OF GAS-STEAM TURBINE USING A HYBRID METHOD
PublikacjaThis paper relates to the CFD calculation of a new turbine type which is in the phase of theoretical analysis, because the working fluid is a mixture of steam and gas generated in wet combustion chamber. At first, this article concentrates on a possibility of streamlining the flow efficiency of a last stage of axial turbine working on gas-steam mixture using a hybrid of the particle swarm optimization algorithm with the Nelder-Mead...
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Flexomagnetic response of buckled piezomagnetic composite nanoplates
PublikacjaIn this paper, the equation governing the buckling of a magnetic composite plate under the influence of an in-plane one-dimensional magnetic field, assuming the concept of flexomagnetic and considering the resulting flexural force and moment, is investigated for the first time by different analytical boundary conditions. To determine the equation governing the stability of the plate, the nonlocal strain gradient theory has been...
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Torsional stability capacity of a nano-composite shell based on a nonlocal strain gradient shell model under a three-dimensional magnetic field
PublikacjaThis paper considers a single-walled composite nano-shell (SWCNS) exposed in a torsional critical stability situation. As the magnetic field affects remarkably nanostructures in the small size, a three-dimensional magnetic field is assessed which contains magnetic effects along the circumferential, radial and axial coordinates system. Based on the results of the nonlocal model of strain gradient small-scale approach and the first-order...
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Aproksymacja zmian stężenia znacznika w badaniach pCT płuc
PublikacjaW artykule zaproponowano nową metodę aproksymacji zmian stężenia znacznika w badaniach pCT płuc. Zmiany stężenia znacznika są skanowane z częstotliwością kilkakrotnie większą niż częstotliwość oddechu. Metoda opiera się na spostrzeżeniu, że częstotliwość występowania pików na krzywych zmian stężenia znacznika jest równa częstotliwości oddechu badanego. Zaprezentowano przykładowe dopasowanie funkcji regresji w postaci krzywej Gaussa...
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Emotion Monitor - Concept, Construction and Lessons Learned
PublikacjaThis paper concerns the design and physical construction of an emotion monitor stand for tracking human emotions in Human-Computer Interaction using multi-modal approach. The concept of the stand using cameras, behavioral analysis tools and a set of physiological sensors such as galvanic skin response, blood-volume pulse, temperature, breath and electromyography is presented and followed...
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Pipeline System for Heat Transportation from Nuclear Power Plant – an Optimizing Approach
PublikacjaOver the last few years heat piping insulation technology and pump systems efficiency have been significantly improved. Reduced thermal losses encourage heat transportation over long distances. It provides an opportunity for increasing thermodynamic efficiency of Nuclear Power Plants (NPPs) that are often located in rural areas because of safety issues. It can be achieved by Combined Heat and Power (CHP) generation, as heat produced...
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Portable exhaled breath analyzer employing fluctuation-enhanced gas sensing method in resistive gas sensors
PublikacjaThis paper presents a portable exhaled breath analyser, developed to detect selected diseases. The set-up employs resistive gas sensors: commercial MEMS sensors and prototype gas sensors made of WO3 gas sensing layers doped with various metal ingredients. The set-up can modulate the gas sensors by applying UV light to induce physical changes of the gas sensing layers. The sensors are placed in a tiny gas chamber of a volume...
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DIGITAL HYDRAULICS CIRCUIT BASED ON PWM FUNCTION FOR CONTROLLING HYDRAULIC ACTUATOR POSITION
PublikacjaHydraulic systems are used in many different industries, such as multi-source hydrostatic drive systems. In traditional hydraulic systems, a proportional servo valve is used to control the position of hydraulic actuators. The low energy efficiency and high cost of these control valves are two major problems with these systems. Digital hydraulics is one of the most unique ideas on how to solve these problems. Researchers like digital...
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Recent developments in biological sample testing methods for the confirmation of gestational exposure to tobacco smoke anddrugs of abused
PublikacjaSubstance use is most prevalent in reproductive-aged people also by women during pregnancy. In national prevalence surveys among women aged 15 to 44 years, 10.8 % of women reported using alcohol during pregnancy, 17 % reported smoking during pregnancy, and 4.4 % reported abusing any illicit substances during pregnancy. Virtually all illegal drugs, such as heroin and cocaine, pose dangers to a pregnant woman. Legal substances, such...
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Effects of consecutive apneas on pial artery pulsation and subarachnoid width in healthy subjects
PublikacjaHypercapnia 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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Experimental study on steel columns subjected to impact load under earthquake conditions
PublikacjaEarthquakes affecting urbanized regions cause exceptional loads to load bearing structural elements such as columns. Such a boost in the load conditions can lead to severe damages which, in a worst case scenario, can lead to a total collapse of a building. This boost is caused by the horizontal ground movement generating a rise in the internal forces due to considerable large displacement between the top and bottom support of columns....
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Problems of analytical determination of journal bearing bush fatigue strength estimates
PublikacjaProblems connected with determination of stress distribution in sliding layer of thinwalled bearing bushes, investigated in bearing fatigue test rigs, have been presented. Using an example of plain bearings tested in the fatigue machine SMOK (built at the Gdask University of Technology) problems with obtaining a convergence of iterative procedure for determining the fatigue strength estimators of bearing alloy surface layer are...
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Profile irregularities of turned surfaces as a result of machine tool interactions
PublikacjaThe paper describes the influence of the machining operation on a surface, which disturbs the projection of the tool profile in the form of its relative movements with respect to the object. The elements of the machine tool undergo constant wear during the machining process, it is therefore important to recognize the effects of their influence on the surface's irregularities. Amplitude-frequency analysis of lateral profiles has...
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Design and optimization of a novel miniaturized low-profile circularly polarized wide-slot antenna
PublikacjaThis paper presents a novel structure of a compact circularly polarized (CP) antenna. CP is obtained using a parasitic quasi-rectangular strip placed coplanar to the feedline. A ground plane perturbation combined with the asymmetric geometry of the coplanar waveguide ground planes is utilized to excite additional CP modes. All antenna dimensions are rigorously optimized to achieve the best possible performance in terms of the impedance...
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Correlation between natural frequencies and buckling load in a stiffened shell
PublikacjaThe paper deals with correlation between natural frequencies and buckling load of a stiffened shell composed of corrugated sheets and vertical stiffeners (columns). The simplified shell segment represents the buckling behaviour of a whole silo with sparsely distributed columns. The paper covers variants of linear buckling anal-yses, dynamic eigenvalue analyses and geometrically non-linear analyses of a segment modelled with shell...
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The influence of polymer bearing material and lubricating grooves layout on wear of journal bearings lubricated with contaminated water
PublikacjaThe goal of the present paper is to investigate wear properties of journal sliding bearing operating in the conditions of contaminated water lubrication. Several bearing materials and bearing sleeve designs (differing in the axial grooves position and their shape) were tested experimentally under typical operating conditions in a dedicated test rig, which was equipped with a lubricating system, enabling lubrication with contaminated...
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On the plastic buckling of curved carbon nanotubes
PublikacjaThis research, for the first time, predicts theoretically static stability response of a curved carbon nanotube (CCNT) under an elastoplastic behavior with several boundary conditions. The CCNT is exposed to axial compressive loads. The equilibrium equations are extracted regarding the Euler–Bernoulli displacement field by means of the principle of minimizing total potential energy. The elastoplastic stress-strain is concerned...
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Experimental investigations and damage growth modeling of EN‐AW 2024 aluminum alloy under LCF loading accounting creep pre‐deformation
PublikacjaThis article presents the results of experimental tests of creep rupture and of low-cycle fatigue (LCF) of EN-AW 2024 aluminum alloy devoid of damage and having preliminary damage. The preliminary damage was dealt in the process of creep at elevated temperature 100C, 200C, and 300C until achievement of two different strain values at each temperature. Samples with preliminary damage were subjected to fatigue tests at room temperature....
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Optimal placement of IMU sensor for the detection of children activity
PublikacjaIn this paper an investigation to determine the optimal placement of IMU sensors for the purpose of children characteristic activity detection is presented. The article compares four different placement of two IMU sensors on human body. Ten healthy volunteers participated within the study. Data were collected firstly from two wireless 9-axial IMU sensors placed at the left and right wrists, then sensors were placed at lower back...
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The new concept of capillary forces aided evaporator for application in domestic organic rankine cycle
PublikacjaThis 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...
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Inhibitors of angiogenesis in cancer therapy – synthesis and biological activity
PublikacjaAngiogenesis is the process of formation of new capillaries from preexisting blood vessels. Angiogenesis is involved in normal physiological processes, and plays an important role in tumor invasion and development of metastases. Vascular endothelial growth factor (VEGF) plays a key role in angiogenesis. VEGF is a mitogen for vascular endothelial cells and stimulates their proliferation. By inhibiting the biological activity of...
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Perfusion computed tomography: 4 cmversus8 cm coverage size in subjects with chronic carotid artery stenosis
PublikacjaOBJECTIVE: The impact of coverage size on global cerebral blood flow (CBF), cerebral blood volume (CBV), mean transit time (MTT) and time to peak (TTP) parameters has not been investigated in patients with chronic carotid artery stenosis. METHODS: 63 patients with stenosis of >70% within a single internal carotid artery and neurological symptoms were randomly assigned to two well-matched groups. Differences in CT perfusion scan...
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2-Methoxyestradiol and Hydrogen Peroxide as Promising Biomarkers in Parkinson’s Disease
PublikacjaEstrogens function in numerous physiological processes including controlling brain cell growth and differentiation. 2-Meth- oxestradiol (2-ME2), a 17β-estradiol (E2) metabolite, is known for its anticancer effects as observed both in vivo and in vitro. 2-ME2 affects all actively dividing cells, including neurons. The study aimed to determine whether 2-ME2 is a potentially cancer-protective or rather neurodegenerative agent in a...
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Computed tomography indicators of cerebral microperfusion improve long term after carotid stenting in symptomatic patients
PublikacjaOBJECTIVES: We tested the hypothesis that computed tomography (CT) perfusion markers of cerebral microcirculation would improve 36 months after internal carotid artery stenting for symptomatic carotid stenosis while results obtained 6-8 weeks after the stenting procedure would yield a predictive value. METHODS: We recruited consecutive eligible patients with >70% symptomatic carotid stenosis with a complete circle of Willis and...
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Estimation of Oxidative Stress Markers in Chronic Kidney Disease
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KONCEPCJA DWU-ŚMIGŁOWEJ ELEKTROWNI WIATROWEJ I ELEKTROWNI SZCZYTOWO-POMPOWEJ NA WZGÓRZU SZUBIENICZNYM
PublikacjaDogodne warunki terenowe Wzgórza Szubienicznego w Gdańsku oraz istniejąca tam infrastruktura stanowią podstawę do rozważenia koncepcji doposażenia instalacji badawczej Laboratorium Innowacyjnych Technologii Elektroenergetycznych i Integracji Odnawialnych Źródeł Energii LINTE^2 w skojarzony, hydro-wiatrowy zespół wytwórczy. W artykule zaproponowano koncepcję budowy elektrowni pompowo-szczytowej z turbinami Francisa oraz elektrowni...
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Monitoring of CRT by means of impedance multiple measurements - simulation studies
PublikacjaCardiac resynchronization therapy (CRT) is a very promising treatment for patients with congestive heart failure. An Impedance Cardiography (ICG) is used for evaluation of heart mechanical activity. A simulation study with the use of a FEM model was performed. The developed realistic model of the thorax, based on CT data obtained from examination of a 68-year-old man, consisted of 212 000 tetrahedral elements. Different configurations...
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BIOMATERIALS AND IMPLANTS IN CARDIAC AND VASCULAR SURGERY - REVIEW
PublikacjaCurrently, on prosthesis in cardiac blood vessels and heart valves are used materials of animal or synthetic origin. For animal materials include, among others pericardial sac in which is the heart. Materials such as this (natural) are characterized by a remarkable biocompatibility within the human body, but their main disadvantage is the relatively low durability. In turn, synthetic materials, which include the austenitic chromium-nickel-molybdenum...
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Numerical Model of the Aortic Valve Implanted Within Real Human Aorta
PublikacjaCardiovascular system diseases are the main cause of deaths in developed and developing countries. The main reasons are myocardial infarction, heart failure, stroke and valvular diseases. These are caused mainly by arteriosclerosis. The valvular diseases involve a significant burden for the health care system and their frequency is rising with the patient age. This work describes the tools and numerical models appropriate for modeling...
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Application of deep eutectic solvents in bioanalysis
PublikacjaThe application of deep eutectic solvents (DESs) is sharply surging as a green alternative to conventional solvents due to their unique properties in terms of simplicity of preparation, designability and low cost. A great deal of attention has been paid to the application of these green solvents in analytical chemistry in recent years, and a lot of interesting work has been reported. This review summarizes the most relevant applications...
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Statistical analysis and robust design of circularly polarized antennas using sequential approximate optimization
PublikacjaIn the paper, reliable yield estimation and tolerance-aware design optimization of circular polarization (CP) antennas is discussed. We exploit auxiliary kriging interpolation models established in the vicinity of the nominal design in order to speed up the process of statistical analysis of the antenna structure at hand. Sequential approximate optimization is then applied to carry out robust design of the antenna, here, oriented...
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Post-critical buckling of truncated conical carbon nanotubes considering surface effects embedding in a nonlinear Winkler substrate using the Rayleigh-Ritz method
PublikacjaThis research predicts theoretically post-critical axial buckling behavior of truncated conical carbon nanotubes (CCNTs) with several boundary conditions by assuming a nonlinear Winkler matrix. The post-buckling of CCNTs has been studied based on the Euler-Bernoulli beam model, Hamilton’s principle, Lagrangian strains, and nonlocal strain gradient theory. Both stiffness-hardening and stiffness-softening properties of the nanostructure...
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Low-Voltage LDO Regulator Based on Native MOS Transistor with Improved PSR and Fast Response
PublikacjaIn this paper, a low-voltage low-dropout analog regulator (ALDO) based on a native n-channel MOS transistor is proposed. Application of the native transistor with the threshold voltage close to zero allows elimination of the charge pump in low-voltage regulators using the pass element in a common drain configuration. Such a native pass transistor configuration allows simplification of regulator design and improved performance,...
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Starter for Voltage Boost Converter to Harvest Thermoelectric Energy for Body-Worn Sensors
PublikacjaThis paper examines the suitability of selected configurations of ultra-low voltage (ULV) oscilla-tors as starters for a voltage boost converter to harvest energy from a thermoelectric generator (TEG). Important properties of particularly promising configurations, suitable for on-chip imple-mentation are compared. On this basis, an improved oscillator with a low startup voltage and a high output voltage swing is proposed. The applicability...
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Properties of New Composite Materials Based on Hydroxyapatite Ceramic and Cross-Linked Gelatin for Biomedical Applications
PublikacjaThe main aim of the research was to develop a new biocompatible and injectable composite with the potential for application as a bone-to-implant bonding material or as a bone substitute. A composite based on hydroxyapatite, gelatin, and two various types of commercially available transglutaminase (TgBDF/TgSNF), as a cross-linking agent, was proposed. To evaluate the impacts of composite content and processing parameters on various...
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ANALIZA AERODYNAMICZNA ŁOPAT NA PRZYKŁADZIE PROJEKTU DWUWIRNIKOWEJ TURBINY WIATROWEJ MAŁEJ MOCY
PublikacjaW artykule przedstawiono proces projektowania oraz analizy aerodynamicznej łopat turbiny wiatrowej z wykorzystaniem metody BEMT (ang. Blade Element Momentum Theory). Dokonano doboru profili aerodynamicznych oraz opisano procedurę wyznaczania optymalnego rozkładu kątów zwichrowania i długości cięciw profili w funkcji długości łopaty dla założonych parametrów wejściowych. Dokonano obliczenia działających sił oraz generowanej mocy...
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Attitudes of oncology patients’ towards biospecimen donation for biobank research
PublikacjaBackground Since the biological material that remains after diagnostic and therapeutic procedures plays crucial role in biobank research, this study aims to explore cancer patients’ views on the donation of biospecimens for research purposes. Methods 548 oncology patients from two hospitals with oncology treatment units in Poznan, Poland,...
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Partial Admission Stages of High Efficiency for a Microturbine
PublikacjaThe paper presents the results of a design analysis of a microturbine for a cogeneration micro-power plant working in accordance with organic Rankine cycle. The heat power of the plant is assumed equal to 20kW and the corresponding available electric output is estimated to be about 3 kW. After the design analysis, the axial turbine with partial admission in all stages was built and tested experimentally. Special attentionwas paid...