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Search results for: NON-STATIONARY THERMAL
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Non-Wave Variations in Temperature Caused by Sound in a Chemically Reacting Gas
PublicationA weakly nonlinear generation of non-acoustic modes in the field of sound in a gas is considered. An exotericchemical reaction of A->B type, which takes place in a gas, may be reversible or not. Two types of sound areconsidered, low-frequency and high-frequency as compared with the characteristic time of a chemical reaction.For both these cases, the governing equations of non-acoustic modes are derived and conclusions of the efficiencyof...
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Non-proportional full-order Luenberger observers of induction motors
PublicationThe paper recapitulates recently conducted investigations of non-proportional Luenberger observers, applied to reconstruction of state variables of induction motors. Three structures of non-proportional observers are analyzed, a proportional-integral observer, modified integral observer and observer with integrators. Criteria for gain selection of the observer are described, classical ones based on poles, as well as additional,...
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An advanced thermal-FSI approach of an evaporation of air heat pump
PublicationThe paper presents selected problems of numerical modeling of an advanced thermal-FSI approach of evaporator of air heat pomp. The example of a fin-tube evaporator has been studied, focusing on obtaining of heat exchanger characteristics applying two-phase flow model for the in-tube refrigerant flow. Special attention is given to heat transfer between separated medium for different air velocity and changed refrigerant mass flow...
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CSR and innovation or CSR as non-technological innovation
PublicationThis chapter investigates the relationship between Corporate Social Responsibility (CSR) and innovation process. There is an ongoing discussion in the literature regarding this relationship, in particular on its one- or bidirectional nature and possible antecedents or mediating factors. This research addresses this gap and aims to provide more conceptual clarity and synthesize the different types of relationships between CSR and...
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Thermal and Mechanical Properties of Microporous Polyurethanes Modified with Reduced Graphene Oxide
PublicationMicroporous polyurethanes (MPU) were modified by adding 0.25%–1.25 wt% of reduced graphene oxide (RGO). The materials were prepared without solvent via in situ polymerization. From a technological point of view, it is very important to obtain functional materials by using reacting compounds only. The thermal characteristics of obtained MPU were investigated using TGA, DSC, and DMA techniques. In comparison to nonmodified microporous...
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Impact of strontium non-stoichiometry of SrxTi0.3Fe0.7O3-δ on structural, electrical, and electrochemical properties for potential oxygen electrode of intermediate temperature solid oxide cells
PublicationThis work presents the results of a comprehensive study on the impact of the A-site non-stoichiometry of SrxTi0.3Fe0.7O3-δ (x = 0.90, 0.95, 1.00, 1.05) ceramics on their physicochemical properties. The materials were fabricated by the conventional solid-state reaction method and their structure was determined by X-ray diffractometry, X-ray photoelectron spectroscopy and electron microscopy. Their sintering and thermal expansion...
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Influence of thermal effects on mechanical properties of PVDF-coated fabric
PublicationThis paper describes the method of laboratory tests necessary for identification of temperature influence on mechanical properties of polyvinylidene fluoride-coated polyester fabric often used for tensile structures. Two nonlinear model descriptions are investigated. The first one is based on the piece-wise linear relations between stress and strain and the second one on the Murnaghan model of solid behavior. This paper is proposed...
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New synthesis route of highly porous InxCo4Sb12 with strongly reduced thermal conductivity
PublicationHighly porous, In-filled CoSb3 skutterudite materials with an attractive thermoelectric figure of merit (ZT * 1) and corresponding dense samples were fabricated through the cost-effective method of reduction in oxides in dry hydrogen and the pulsed electric current sintering (PECS) method, respectively. The reduction process was described in detail using in situ thermogravimetric analysis of Co2O3, Sb2O3 and In(NO3)35H2O separately...
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Determination of Surfactants in Environmental Samples. Part III. Non-Ionic Compounds
PublicationNon-ionic surface active agents are a diverse group of chemicals which have an uncharged polar head and a non-polar tail. They have different properties due to amphiphilic structure of their molecules. Commercial available non-ionic surfactants consist of the broadest spectrum of compounds in comparison with other types of such agents. Typically, non-ionic compounds found applications in households and industry during formulation...
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Thermal properties of polyurethanes synthesized using waste polyurethane foam glycolysates
PublicationW pracy przedstawiono wyniki analizy termicznej (DMTA i TG-FTIR) glikolizatów i otrzymanych z nich poliuretanów. Glikolizaty uzyskiwano w reakcji odpadowej pianki poliuretanowej z 1,6 heksametylenodiolem (HDO) przy różnym stosunku masowym pianki do HDO (1:1 - 10:1). Poliuretany syntezowano metodą dwuetapową z prepolimeru (diizocyjanian MDI + glikolizat), który przedłużano handlowym małocząsteczkowym glikolem.
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Influence of chemical composition of amide block on the thermal properties and structure of terpolymers
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Thermal properties of rare earth elements complexes with 1,3,5-benzenetricarboxylic acid
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Thermal degradation of butyl acrylate-methyl acrylate-acrylic acid-copolymers
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Foamed Polyurethane Composites With Different Types of Ash – Morphological, Mechanical and Thermal Behavior Assessments
Publicationncorporation of two types of ash particles into flexible polyurethane foams has been investigated, wood ash from gasification process and fly ash resulting from coal burning in power plant. Samples were modified with 5, 10 and 15 wt% of fillers. Structure, mechanical and thermal properties of obtained foams were investigated. Incorporation of both types of ash particles resulted in materials showing...
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ARRAY OF MINIJETS – THERMAL AND HYDRAULIC PHENOMENA IN BOUNDARY LAYER
PublicationPresented work considers flow and thermal phenomena occurring in the system consisting of minijets array and heated with constant heat flux surface. Numerical analyses, based on the mass, momentum and energy conservation laws, were conducted. Focus was placed on the proper model construction, in which turbulence and boundary layer modelling was crucial. Calculations were done for various mass flow rates. The main calculations were...
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Real-time facial feature tracking in poor quality thermal imagery
PublicationRecently, facial feature tracking systems have become more and more popular because of many possible use cases. Especially in medical applications location of the face and facial features are very useful. Many researches have presented methods to detect and track facial features in visible light. However, facial feature analysis in thermography may also be very advantageous. Some examples of using infrared imagery in medicine include...
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Effect of surface roughness on thermal-hydraulic characteristics of plate heat exchanger
PublicationIn the paper the experimental analysis of passive heat transfer intensification in the case of modeled plate heat exchanger is conducted. The plate heat exchanger is chosen for the analysis because this kind of heat exchangers could be prospectively applied in the ORC systems, however other areas or application are equally possible. The experimental setup was assembled at the Department of Energy and Industrial Apparatus of Gdansk...
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Evaluation of respiration rate and pattern using a portable thermal camera
PublicationThe goal of this paper was to analyze the accuracy of the proposed method for the evaluation of respiration rate and respiration rhythm patterns (e.g. inspiration slope) using the portable and mobile thermal camera module that could be a part of smart glasses. Parameters were analyzed for 12 volunteers in two experiments, when subjects speak and do not speak. The pressure, chest belt was used as a reference measurement method....
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Polyfunctional chemically bonded stationary phase for reversed phase high-performance liquid chromatography
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Quantitative structure–retention relationships of ionic liquid cations in characterization of stationary phases for HPLC
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Air journal bearing utilizing near-field acoustic levitation: stationary shaft case
PublicationResults of a study to examine a unique idea of self-levitating journal bearing are presented in this paper. the idea represents a radical departure from the current bearing technology. it utilisesacoustic levitation, which relies on the sound energy radiated by an object supporting a load. acoustic levitation has been demonstrated to support loads of up to 10 kg. in order to support a load theacoustic wave emitted by the radiating...
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The external walls of a passive building: A classification anddescription of their thermal and optical properties
PublicationThis paper attempts a new classification of insulating materials from the perspective of their utility in thepro-ecological passive construction industry. The main criterion is the conductivity of thermal and solarenergy. Based on their ability to conduct or block fluxes of thermal and solar energy, six types of insulatingwalls are proposed. On the basis of this criterion there are traditional dividing walls (typical walls, wallinsulating...
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A Comparison of Empirical Correlations of Viscosity and Thermal Conductivity of Water-Ethylene Glycol-Al2O3 Nanofluids
PublicationBecause of their superb thermal conductivity, nanofluids are seen as new generation of cooling mediums in many engineering applications. It is well established that even a small amount of nanoparticles mixed with a base fluid may result in distinct thermal conductivity enhancement. On the other hand, addition of nanoparticles to the base fluid results in its substantial viscosity increase. Therefore, it is very dicult to evaluate...
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Thermal ablation modeling via the bioheat equation and its numerical treatment
PublicationThe phenomenon of thermal ablation is described by Pennes’ bioheat equation. This model is based on Newton’s law of cooling. Many approximate methods have been considered because of the importance of this issue. We propose an implicit numerical scheme which has better stability properties than other approaches.
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Thermal Imaging Aided Assessment of a State of Equipment Under Test and its Protecting Elements
PublicationIn the paper the investigation results using thermal imaging methods are presented. The examined is a state of equipment under test and its protecting components. The estimations are done for the chosen protecting elements during surge immunity testing. The results show that the thermal imaging methods are useful for early detection of possible damage of a device being tested
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Risk of power cables insulation failure due to the thermal effect of solar radiation
PublicationLow-voltage, as well as high-voltage power cable lines, are usually buried in the ground. The ampacity of the power cables in the ground mainly depends on the thermal resistivity of the soil, which may vary in a wide range. A common practice in power cable systems performance is to supply them from a pole of an overhead line. If so, a section of the line is located in free air and can be directly exposed to solar radiation. In...
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Thermal-Resistant Polyurethane/Nanoclay Powder Coatings: Degradation Kinetics Study
PublicationIn the present study, thermal degradation kinetics of polyurethane (PU) powder coatings reinforced with organo-modified montmorillonite (OMMT) was investigated. PU nanocomposites were prepared in different concentrations of 1, 3, and 5 wt.% of OMMT via the extrusion method. The microstructure of the nanocomposites was observed by scanning electron microscope (SEM) illustrating uniform dispersion of OMMT nano-clay platelets in the...
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Deep Features Class Activation Map for Thermal Face Detection and Tracking
PublicationRecently, capabilities of many computer vision tasks have significantly improved due to advances in Convolutional Neural Networks. In our research, we demonstrate that it can be also used for face detection from low resolution thermal images, acquired with a portable camera. The physical size of the camera used in our research allows for embedding it in a wearable device or indoor remote monitoring solution for elderly and disabled...
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Thermal-FSI modeling of flow and heat transfer in a heat exchangerbased on minichanels
PublicationIn this paper selected numerical modelling problems for an advanced thermal-FSI ("Fluid Solid Interaction") mini-channel heat exchanger model are presented. Special attention is given to the heat transfer between the separated mediums for different mass flows. Similar modelling problems have also been discussed in the literature dedicated to numerical and theoretical modelling problems for typical heat exchangers [1, 2, 3]. Basic...
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Influence of Thermal Imagery Resolution on Accuracy of Deep Learning based Face Recognition
PublicationHuman-system interactions frequently require a retrieval of the key context information about the user and the environment. Image processing techniques have been widely applied in this area, providing details about recognized objects, people and actions. Considering remote diagnostics solutions, e.g. non-contact vital signs estimation and smart home monitoring systems that utilize person’s identity, security is a very important factor....
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Positive solutions to Sturm–Liouville problems with non-local boundary conditions
PublicationIn this paper, the existence of at least three non-negative solutions to non-local boundary-value problems for second-order differential equations with deviating arguments α and ζ is investigated. Sufficient conditions, which guarantee the existence of positive solutions, are obtained using the Avery–Peterson theorem. We discuss our problem for both advanced and delayed arguments. An example is added to illustrate the results.
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Thermal Image Processing for Respiratory Estimation from Cubical Data with Expandable Depth
PublicationAs healthcare costs continue to rise, finding affordable and non-invasive ways to monitor vital signs is increasingly important. One of the key metrics for assessing overall health and identifying potential issues early on is respiratory rate (RR). Most of the existing methods require multiple steps that consist of image and signal processing. This might be difficult to deploy on edge devices that often do not have specialized...
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Tubular House - Form Follows Technology, Concrete Shell Structure with Inner Thermal Insulation
PublicationThe aim of this paper is the theoretical analysis of the possibilities and limitations of using an unconventional technology and the original architectural form stemming from it – the building with external construction and internal insulation. In Central European climatic conditions, the traditional solution for the walls of heated buildings relies on using external thermal insulation. This stems from building physics: it prevents...
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Experimental Study on Dynamics of Wooden House Wall Panels with Different Thermal Isolation
PublicationWood frame buildings are very popular in regions that are exposed to different dynamic excitations including earthquakes. Therefore, their seismic resistance is really important in order to prevent structural damages and human losses. The aim of the present paper is to show the results of experimental tests focused on the dynamic response of wall panels of a wooden frame building with thermal isolation made of mineral wool and...
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How non-technological innovation saved the day by using ICT
PublicationCertainly, the current pandemic situation provides a lot of evidence of the need for non-technological innovations, both in the area of company organization and marketing. Socio-cultural innovations are not less important. Therefore, the role of non-technological innovation during the COVID-19 pandemic is discussed in the sixth chapter. Innovations supported by digital solutions have become a silent heroes for many companies as...
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CAUSALITY IN MODELS OF THERMAL PROCESSES IN SHIP ENGINE ROOMS WITH THE USE OF BOND GRAPH (BG) METHOD
PublicationWith a single approach to modeling elements of different physical nature, the method of Bond Graph (BG) is particularly well suited for modeling energy systems consisting of mechanical, thermal, electrical and hydraulic elements that operate in the power system engine room. The paper refers to the earlier presented new concept of thermal process modeling using the BG method. The authors own suggestions for determining causality...
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Analysis of the Heating Process of Hydraulic Motors during Start-Up in Thermal Shock Conditions
PublicationConditions that prevail during harsh winters and hot summers pose a serious challenge for machine designers building devices suitable for operation in extreme weather. It is essential for the designers and the users to define the principles and conditions for the safe operation of machines and devices with hydraulic drive in low ambient temperatures. Bearing in mind the above, the author tested the hydraulic motors in thermal shock...
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Non-Linear Control of Electrical Machines Using Non-Linear Feedback
PublicationPrzedstawiono zasady nieliniowego sterowania oraz zastosowanie nielinowego sprzężenia zwrotnego do maszyn elektrycznych. Opisano nieliniowe sterowanie obcowzbudnym silnikiem prądu stałego. Zaprezentowano multiskalarne modele maszyn prądu przemiennego. Maszynę indukcyjną zamodelowano z wykorzystaniem strumienia wirnika oraz z wykorzystaniem strumienia stojana. MMultiskalarne modele maszyny indukcyjnej wykorzystano do nieliniowego...
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Rethinking non-governmental organizations – at the crossroad of economics and civil society
PublicationThe article aims to close the existing knowledge gaps, show why non‑governmental organizations are founded and maintained, and elaborate and systematize the existing knowledge through an analysis of the existing subdisciplines within economics, laying the groundwork for the economics of non‑governmental organizations. The article was written based on a structured literature review with an approach similar to the grounded theory...
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Thermal sequences database of the skin flaps in breast reconstruction and burns
PublicationThis 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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Thermal sequences database of the skin flaps in breast reconstruction and burns
PublicationThis 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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Accuracy Investigations of Turbine Blading Neural Models Applied to Thermal and Flow Diagnostics
PublicationPossibility of replacing computional fluid dynamics simulations by a neural model for fluid flow and thermal diagnostics of steam turbines is investigated. Results of calculations of velocity magnitude of steam for 3D model of the stator of steam turbine is presented.
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Flood Routing by the Non-Linear Muskingum Model: Conservation of Mass and Momentum
PublicationIn this paper, the conservative properties of the Muskingum equation, commonly applied to solve river flood routing, are analysed. The aim of this analysis is to explain the causes ofthe mass balance error, which is observed in the numerical solutions of its non-linear form. The linear Muskingum model has been considered as a semi-discrete form of the kinematic wave equation and therefore it was possible to derive its two non-linear...
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A robust sliding mode observer for non-linear uncertain biochemical systems
PublicationA problem of state estimation for a certain class of non-linear uncertain systems has been addressed in this paper. In particular, a sliding mode observer has been derived to produce robust and stable estimates of the state variables. The stability and robustness of the proposed sliding mode observer have been investigated under parametric and unstructured uncertainty in the system dynamics. In order to ensure an unambiguous non-linear...
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Water-lubricated stern tube bearing - experimental and theoretical investigations of thermal effects
PublicationThe paper presents research results of thermal phenomena accompanying operation of a water-lubricated stern tube bearing with axial grooves. Experimental tests revealed, that intensity of forced axial flow has strong influence on bush temperature. Numerical simulations focused on investigation of the thermal phenomena under operation of water-lubricated journal bearing showed, that restricted axial flow promotes backflow of the...
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Quantitative active dynamic thermal Ir-Imaging and thermal tomography in medical diagnostics
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Quantitative active dynamic thermal ir-imaging and thermal tomography in medical diagnostics
PublicationPraca dotyczy nowych technik obrazowania w diagnostyce medycznej, wykorzystując przetwarzanie obrazów termicznych rejestrowanych w podczerwieni. Opisano właściwości termiczne tkanek biologicznych, omówiono medele termiczne i zdefiniowano zastępcze parametry syntetyczne, metody pomiarów i stosowane urządzenia. Omówiono procedury akwizycji danych i ich przetwarzania. Wprowadzono pojęcie tomografii termicznej. Opisano przeprowadzone...
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Quantitative Active Dynamic Thermal IR-Imaging and Thermal Tomography in Medical Diagnostics
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TESTING CONTRACTION AND THERMAL EXPANSION COEFFICIENT OF CONSTRUCTION AND MOULDING POLYMER COMPOSITES
PublicationThe paper presents results of systematic tests of contraction and thermal expansion coefficients of materials based on polymer composites. The information on the above material properties is essential both at the design stage and during the use of finished products. Components for the samples were selected in such a way as to represent typical materials used for production of construction and moulding elements. The performed tests...
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The application of non-destructive methods in the diagnostics of the approach pavement at the bridges
PublicationThe article presents the possibility of using non-destructive methods of road pavement diagnostics as an alternative to traditional means to assess the reasons for premature cracks adjacent to bridge objects. Two scanning methods were used: laser scanning to measure geometric surface deformation and ground penetrating radar (GPR) inspection to assess the road pavement condition. With the use of a laser scanner, an effective tool...