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Wyniki wyszukiwania dla: THERMAL EFFECTS
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Experimental investigation of thermal energy storage in shell-and-multi-tube unit with nano-enhanced phase change material
PublikacjaThis paper deals with thermal energy storage with use of nanoparticle enhanced phase change material in shell-and-multitube unit. The experiments are conducted under atmospheric pressure. Paraffin wax and two different fatty acids are used as base phase change material. Graphite and multi-walled carbon nanotubes serve as nanoparticles. Graphite nanoparticles are tested at the concentrations of 0.1%, 1% and 5% by weight, while multi-walled...
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Study on effective front region thickness of PCM in thermal energy storage using a novel semi-theoretical model
PublikacjaThermal energy storage in mobile applications, particularly battery of electric vehicles, is currently gaining a lot of importance. In this paper, a semi-theoretical time-dependent mathematical model of the phase change in a double shell thermal energy storage module has been developed where the inner tube is a heat exchange surface. An effective front region thickness for the melting and solidification process has been studied....
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Thermal dewetting as a method of surface modification of the gold thin films for surface plasmon resonance based sensor applications
PublikacjaHere, we report a quick and simple approach with low, optimized production costs to obtain surface plasmon resonance (SPR) based sensors fabricated through a time- and resource-effective method based on thermal dewetting of thin Au films. From the applicative point of view, the method of detection presented here should be easier to implement, since light transmission measurements seem to be much less challenging than light refractive...
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The motion influence on respiration rate estimation from low-resolution thermal sequences during attention focusing tasks
PublikacjaGlobal aging has led to a growing expectancy for creating home-based platforms for indoor monitoring of elderly people. A motivation is to provide a non-intrusive technique, which does not require special activities of a patient but allows for remote monitoring of elderly people while assisting them with their daily activities. The goal of our study was to evaluate motion performed by a person focused on a specific task and check...
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Comparison of the exponential thermal transient parameterization methods with the SMTP method in the unipedicled DIEP flap computer modelling and simulation
PublikacjaThe aim of this paper is to compare the spatial contrast of the image descriptors obtained via three different thermal transient parameterization methods in Active Dynamic Thermography. The thermal constants and amplitude values of the one- and two- exponential parametrization are compared to the Simplified Magnitude-Temporal Parametrization method (SMTP). The comparison is performed using the data obtained by simulating the cold...
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Thermal utilization of meat and bone meals. Performance analysis in terms of drying process, pyrolysis and kinetics of volatiles combustion
PublikacjaA development of technology of thermal utilization requires a thorough knowledge of the physicochemical properties, as well as kinetics of combustion of volatiles and char. Due to waste management regulations the meat and bone meal (MBM) is regarded as biofuel constituting one of the alternatives to fossil fuels in the energy market. MBM is a heterogeneous material that may consist of several different fractions. The extensive...
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Synthesis of reduced graphene oxide nanosheets using nanofibers from methane and biogas thermal decomposition with various catalysts
PublikacjaReduced graphene oxide and graphene oxide (rGO, GO) were synthesised from carbon nanofibers, which were formed in catalytic thermal decomposition of methane (CDM) and biogas with different catalysts used in the process. The aim of the work was valorization of CDM carbon nanofiber products. The samples were characterized using Raman spectra, a scanning electron microscope and a transmission electron microscope. As a result, we observe...
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Fully bio-based poly(propylene succinate) synthesis and investigation of thermal degradation kinetics with released gases analysis
PublikacjaOne of the most important information about polyesters is their thermal stability and phase transition tem- peratures. These characteristics give information about the promising behavior of the polyester during proces- sing. In this work, linear bio-based polyester polyols were prepared with the use of succinic acid and 1.3- propanediol (both with natural origin). As a polycondensation catalyst was used tetraisopropyl orthotitanate...
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Processing, physico-mechanical and thermal properties of reclaimed GTR and NBR/reclaimed GTR blends as function of various additives
PublikacjaIn this work, ground tire rubber (GTR) was mechano-chemically reclaimed in the presence of bitumen and various additives. During studies three types of processing and curing additives: (i) peptizer P300; (ii) vulcanization accelerator tetramethylthiuram disulfide (TMTD) and (iii) organic peroxide di(2-tert-butyl-peroxyisopropyl)benzene (BIB1) were applied to enhance reclaiming of GTR. Reclaiming process was evaluated by oscillating...
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Structure, Mechanical, Thermal and Fire Behavior Assessments of Environmentally Friendly Crude Glycerol-Based Rigid Polyisocyanurate Foams
PublikacjaIn this work, rigid polyisocyanurate foams were prepared at partial substitution (0–70 wt%) of commercially available petrochemical polyol, with previously synthesized biopolyol based on crude glycerol and castor oil. Influence of the biopolyol content on morphology, chemical structure, static and dynamic mechanical properties, thermal insulation properties, thermal stability and flammability was investigated. Incorporation of...
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Effect of crystallinity on structural, thermal, and in vitro dissolution properties of Na2O-CaO-Nb2O5/MgO-P2O5 glass-ceramics
PublikacjaThe impact of the crystallinity on structural, thermal, and in vitro dissolution properties were examined for Na2O- CaO-Nb2O5/MgO-P2O5 glasses/glass-ceramics. Glass-ceramics were synthesized via a spontaneous crystallization process. The Nb content in the materials increased with melting temperature, furthermore, the crystallinity is proportional to the Nb content. The presence of crystalline niobates and phosphates is confirmed...
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A novel DEM-based pore-scale thermal-hydro-mechanical model for fractured non-saturated porous materials
PublikacjaDo propagacji pęknięć wykorzystano nowy oparty na DEM, termiczno-hydromechaniczny model dwufazowego przepływu płynu w skali porów rozszerzony o wymianę ciepła w nienasyconych materiałach porowatych o małej porowatości. Wykonano obliczenia numeryczne dla kohezyjnych próbek ziarnistych przy użyciu DEM w pełni sprzężonego z CFD (opartego na sieci przepływu płynu) i wymianą ciepła, który zintegrował mechanikę dyskretną z mechaniką...
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Metoda f-chart w zastosowaniu do projektu instalacji solarnej w budownictwie jednorodzinnym
PublikacjaW artykule przedstawiono algorytm obliczeń cieplnych związanych z konwersją promieniowania cieplnego oraz analizę efektów pracy instalacji solarnej przy użyciu metody korelacyjnej f-chart. Zaprezentowany algorytm obliczeń cieplnych oraz omówiona w artykule podstawowa odmiana metody f-chart zostały poparte przykładem obliczeniowym dla instalacji solarnej, która wykorzystywana jest do wspomagania układu przygotowania c.w. dla potrzeb...
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Photovoltaic module temperature stabilization with the use of phase change materials
PublikacjaThe worldwide growth of photovoltaics (PVs) has formed an exponential curve for more than four decades. During this period of time, PVs have evolved from a pure niche market of small-scale applications towards becoming a mainstream electricity source. The influence of temperature on the electrical parameters of crystalline silicon solar cells and solar modules is well described in the literature. In order to diminish these effects,...
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Charge density wave and crystalline electric field effects in TmNiC2
PublikacjaSingle crystals of TmNiC2 were grown by the optical floating-zone technique and were investigated by x-ray diffraction (XRD), thermal expansion, electrical resistivity, specific heat, and magnetic susceptibility measurements. Single-crystal XRD reveals the formation of a commensurate charge density wave (CDW) characterized by a CDW modulation vector q2c = (0.5, 0.5, 0.5), which is accompanied by a symmetry change from the orthorhombic...
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MHD Casson flow across a stretched surface in a porous material: a numerical study
PublikacjaIn this study, we examine the nature of magnetohydrodynamic (MHD) Casson flow of fluid across a stretched surface in a porous material. It studies how the behaviour of Casson fluids is affected by a number of variables, including thermal radiation, chemical processes, Joule heating, and viscosity dissipation. The Keller box strategy, based on the finite difference method (FDM), is used to tackle the complex numerical problem. Graphical...
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Heat transfer intensification by jet impingement – numerical analysis using RANS approach
PublikacjaJet impingement is a method of the heat transfer enhancement applied in the engineering systems. The idea is to generate fast-flow fluid jet which impinge on the heated (or cooled) surface, causing significantly higher heat transfer rate. Although some flat surface jet impingement cases are described in the literature, the validated data is still limited. The reason is coming from the fact, that these flows are hydrodynamically...
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Pressure effects on the superconductivity of the HfPd2Al Heusler compound: Experimental and theoretical study
PublikacjaPolycrystalline HfPd2Al has been synthesized using the arc-melting method and studied under ambient-pressure conditions by x-ray diffraction from room temperature up to 450 °C. High-pressure x-ray diffraction up to 23 GPa was also performed using Diacell-type membrane diamond anvil cells. The estimated linear thermal expansion coefficient was found to be α=1.40(3)×10−5K−1, and the bulk modulus derived from the fit to the third-order...
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The Influence of a Photovoltaic Micro-Installation on the Low-Frequency Parameters of Electricity at PCC and Its Impact on the Thermal Characteristics of Selected Devices
PublikacjaThis manuscript illustrates the measurement results of parameters describing the quality of energy at the PCC (point of common coupling) of a photovoltaic micro-installation that can significantly affect devices in the same power grid. The analyses reflecting heating of selected devices used in domestic installations, which were performed in an isolated laboratory environment, are also indicated. The conducted study aimed at checking...
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Influence of Thermal Decomposition of Wood and Wood-Based Materials on the State of the Atmospheric Air. Emissions of Toxic Compounds and Greenhouse Gases
PublikacjaThis paper presents the energy characteristics of wood and wood-based materials in the form of commercially available pellets, furniture board (MDF) and OSB. Toxicometric indices were determined for gaseous destructs arising from thermal decomposition and combustion of the materials studied. The paper proves that combustion conditions are crucial in terms of toxic destructive emissions. It has been shown that the combustion of...
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Structural, thermal and energetic characteristics of synthetic active carbons prepared on the basis of ion-exchange resin Amberlite IRC 84
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Non-thermal atmospheric pressure plasma as a powerful tool for the synthesis of rhenium-based nanostructures for the catalytic hydrogenation of 4-nitrophenol
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Membrane extraction with sorbent interface-gas chromatography as an effective and fast means for continuous monitoring of thermal degradation products of polyacrylonitrile
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Thermal behavior of the highly luminescent poly(3-hydroxybutyrate):Eu(tta)3(H2O)2 red-emissive complex
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Heteroleptic cadmium(II) complex, potential precursor for semiconducting CdS layers. Thermal stability and non-isothermal decomposition kinetics
PublikacjaW ramach pracy zweryfikowano stabilność termiczną [Cd{SSi(OBut)3}(S2CNEt2)]2 - potencjalnego prekursora do otrzymywania warstw półprzewodnikowych CdS. Równocześnie przeprowadzono analizę kinetyki rozkładu za pomocą różnych metod izokonwersyjnych zaproponowanych przez Flynn-Wall-Ozawa, Kissinger-Akahira-Sunose i Friedmanna w wyniku czego wyznaczono całkowity tryplet kinetyczny dla omawianego kompleksu.
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Dynamic mechanical properties and thermal degradation process of the compositions obtainedfrom unsaturated poly(ester urethanes) cross-linked with styrene
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Thermal and mechanical properties of polyamide 12/modified carbon nanotubes composites prepared via the in situ ring-opening polymerization
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Thermal and spectroscopic profiles variation of cold-pressed raspberry seed oil studied by DSC, UV/VIS, and FTIR techniques
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The influence of chemical composition of amide block on the thermal properties and structure of terpoly(ester-b-ether-b-amide) elastomers
PublikacjaMultiblock terpolymers-(PBT-b-PTMO-b-PA12,10)(n)- constituting the polymer systems, in which one of the three blocks (PBT) does not dissolve in PA12,10 block (hard phase) and, depending on its molecular weight is slightly soluble in PTMO block (soft phase), have been obtained. The DSC method was applied to investigate the thermal properties of these polymers and it was found that PBT block acts as an element that produces stiffness...
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Preliminary Evaluation of Airlaid Nonwovens with Superabsorbent for Use in Protective Footwear: Tests Involving a Thermal Foot Model and Climatic Chamber
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Thermal Aging of Heterophasic Propylene−Ethylene Copolymers: Spatial and Temporal Aspects of Degradation Based on ESR, ESR Imaging, and FTIR
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Determination of the Self-Ignition Behavior of the Accumulation of Sludge Dust and Sludge Pellets from the Sewage Sludge Thermal Drying Station
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Nanosized carbon black as synergist in PP/POE-MA/IFR system for simultaneously improving thermal, electrical and mechanical properties
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Operational control on environmental safety of potentially toxic elements during thermal conversion of metal-accumulator invasive ragweed to biochar
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Chemical Structure and Thermal Properties versus Accelerated Aging of Bio-Based Poly(ether-urethanes) with Modified Hard Segments
PublikacjaAging of polymers is a natural process that occurs during their usage and storage. Predicting the lifetime of polymers is a crucial aspect that should be considered at the design stage. In this paper, a series of bio-based thermoplastic poly(ether-urethane) elastomers (bio-TPUs) with modified hard segments were synthesized and investigated to understand the structural and property changes triggered by accelerated aging. The bio-TPUs...
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The influence of different flame retardants on thermal stability, mechanical and physical properties of rigid polyurethane foams blown with n-pentane
PublikacjaW artykule opisano wpływ klasycznych uniepalniaczy na właściwości sztywnych pianek poliuretanowych. Opisano 7 układów piankowych oraz wyniki charakterystyki fizyczno-mechanicznej oraz stabilności termicznej.
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Co-simulation strategy of transient CFD and heat transfer in building thermal envelope based on calibrated heat transfer coefficients
PublikacjaThe paper presents a strategy to develop a fully transient numerical model of a heat transfer in building, using a transient CFD model of indoor air and a thermal envelope model, running in a co-simulation. The strategy relies on the utilization of RANS with a high-Re turbulence model and a wall function, which enables to use a coarse computational mesh limiting the computational time. Since wall functions give invalid heat transfer...
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Calculation of silicon cell temperature of loaded photovoltaic module based on thermal coefficients for different weather conditions of Northern Poland
PublikacjaWydajność obciążonego modułu fotowoltaicznego zależy silnie od natężenia promieniowania słonecznego, temperatury otoczenia, prędkości wiatru i temperatury wewnętrznej składowych ogniw fotowoltaicznych. Sprawność konwersji fotowoltaicznej spada istotnie wraz z e wzrostem temperatury złącza p-n. Pomiar tej temperatury jest niemożliwy i oblicza się ją w oparciu o mierzoną wartość temperatury przedniej lub tylnej powierzchni modułu...
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Experimental and numerical study of thermal and electrical potential of BIPV/T collector in the form of air-cooled photovoltaic roof tile
PublikacjaAmong renewable energy sources, Building-Integrated Photovoltaic/Thermal (BIPV/T) systems are gaining increasing interest. To improve their economic competitiveness, technologies that increase their efficiency are searched for. The paper is devoted to evaluating the impact of various air-cooling configurations on the thermal and electrical performance of a photovoltaic roof tile. A numerical model of the own experimental system...
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Effect of composition on the thermal properties and structure of M-Al-Si-O-N glasses, M = Na, Mg, Ca
PublikacjaThe primary objective of this study is to explore the relationship between the composition, structure, and thermal characteristics of M-Al-Si-O-N glasses, with M representing sodium (Na), magnesium (Mg), or calcium (Ca). The glasses were prepared by melting in a quartz crucible at 1650 °C and AlN precursor (powder) was utilized as a nitrogen source. The measured thermal properties studied were glass transition temperature (Tg),...
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Automated measurement method for assessing thermal-dependent electronic characteristics of thin boron-doped diamond-graphene nanowall structures
PublikacjaThis paper investigates the electrical properties of boron-doped diamond-graphene (B:DG) nanostructures, focusing on their semiconductor characteristics. These nanostructures are synthesized on fused silica glass and Si wafer substrates to compare their behaviour on different surfaces. A specialized measurement system, incorporating Python-automated code, was developed for an in-depth analysis of electronic properties under various...
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Online Volatile Compound Emissions Analysis Using a Microchamber/Thermal Extractor Coupled to Proton Transfer Reaction-Mass Spectrometry
PublikacjaIndoor air is a complex and dynamic mixture comprising manifold volatile organic compounds (VOCs) that may cause physiological and/or psychological discomfort, depending on the nature of exposure. This technical note presents a novel approach to analyze VOC emissions by coupling a microchamber/thermal extractor (μ-CTE) system to a proton transfer reaction-mass spectrometer (PTR-MS). This configuration provides an alternative to...
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Chemical Characteristics and Thermal Oxidative Stability of Novel Cold-Pressed Oil Blends: GC, LF NMR, and DSC Studies
PublikacjaPlant oils contain a high content of unsaturated fatty acids. Studies of food products have revealed a considerable disproportion in the ratio of ω6 to ω3. This article presents information on the healthful qualities of eight new oil blends that contain a beneficial proportion of ω6 to ω3 fatty acids (5:1), as well as their degradation during heating at 170 and 200 °C. The fatty acid profile was analyzed by gas chromatography (GC),...
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Assessment of Thermal Stresses in Asphalt Mixtures at Low Temperatures Using the Tensile Creep Test and the Bending Beam Creep Test
PublikacjaThermal stresses are leading factors that influence low-temperature cracking behavior of asphalt pavements. During winter, when the temperature drops to significantly low values, tensile thermal stresses develop as a result of pavement contraction. Creep test methods can be suitable for the assessment of low-temperature properties of asphalt mixtures. To evaluate the influence of creep test methods on the obtained low-temperature...
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Effect of Variation of Hard Segment Content and Graphene-Based Nanofiller Concentration on Morphological, Thermal, and Mechanical Properties of Polyurethane Nanocomposites
PublikacjaThis study describes the development of a new class of high-performance polyurethane elastomer nanocomposites containing reduced graphene oxide (RGO) or graphene nanoplatelets (GNP). Two types of polyurethane elastomers with different contents of hard segments (HS) were used as a polymer matrix. The developed nanocomposites were characterized by thermal analysis (DSC, TG), dynamic mechanical testing (DMA), hardness testing, mechanical...
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Structural, thermal and physico-mechanical properties of polyurethane/brewers’ spent grain composite foams modified with ground tire rubber
PublikacjaIn this work, brewers’ spent grain (BSG) and ground tire rubber (GTR) waste fillers were applied as low-cost reinforcement phase in rigid polyurethane foam (PUR). PUR/BSG/GTR composites were prepared by a single step method, using polyglycerol as partial substitute of commercially available petrochemical polyols. Foaming parameters, chemical structure, dynamic mechanical properties, thermal stability, physico-mechanical properties...
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The influence of thermal treatment on electrocatalytic properties of Mn-Co nanofilms on nickel foam toward oxygen evolution reaction activity
PublikacjaThis work evaluates electrodeposited and differently treated Mn-Co catalysts for their oxygen evolution reaction activity. Catalysts are evaluated in the as-deposited and heat treated state: after 350 C and 600 C. Results show that the highest electrochemical activity is obtained for the as-deposited Mn-Co oxyhydroxide, which possibly possess a layered double hydroxide structure. After the heat treatment process, especially after...
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Sustainable synthesis of cyclic carbonates from bio‐based polyether polyol: the structure characterization, rheological behaviour and thermal properties
PublikacjaThe cycloaddition of CO2 to epoxides represents a green efficient method to form bis(cyclic carbonate)s. The main purpose of the work reported in this paper was to examine the effect of the gas flow rate (20, 40, 60 and 100 mL min–1) during carbonation on the conversion yield, chemical structure, rheological behaviour and thermal properties of the prepared compounds. A series of new bis(cyclic carbonate)s was obtained from bio‐based...
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The Course and the Effects of Agricultural Biomass Pyrolysis in the Production of High-Calorific Biochar
PublikacjaThe thermal pyrolysis of agriculture biomass has been studied in a fixed-bed reactor, wherethe pyrolysis was conducted at a steady temperature of 800◦C. This work analyses the pyrolysisproducts of six agricultural wastes: pistachio husks, walnut husks, sunflower hulls, buckwheat husks,corncobs and coconut shells. The conducted research compared examples of large waste biomassstreams from different parts of the world as a potential...
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Honey antibacterial activity: A neglected aspect of honey quality assurance as functional food
PublikacjaBackground Honey is considered as a functional food with health-promoting properties. Its potent antibacterial and antibiofilm effects are the major attributes of so called ‘medical-grade honey’ which is topically used for the treatment of burns, wounds and skin disorders. Nevertheless, the current set of honey quality parameters adopted in the European Union do not include its biological properties. Furthermore, in light of the...