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Search results for: low-temperature cofired ceramics (ltcc)
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Self-supporting LSFO films for bolometers made with LTCC technology
PublicationOpisano metodę wytwarzania przewodzących, tlenkowych warstw ceramicznych tlenków lantanowo-strontowo żelazowych (LSFO) technologią low temperature co-fired ceramics (LTCC). Przedstawiono rezultaty pomiarów parametrów warstw pod kątem przydatności do produkcji detektorów IR.
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Samonośne warstwy LSFO na bolometry wykonane technologią LTCC
PublicationOpisano sposób produkcji ceramicznych, przewodzących warstwtypu perowskitu z niestechiometrycznych tlenków lantanowo-strontowo żelazowych (LSFO) wykonanych technologią LTCC )low temperature co-fired ceramics). Zaprezentowano pomiary parametrów tych warstw, charakteryzujących ich przydatność do produkcji bolometrów.
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Optymalizacja warunków pracy grubowarstwowych bolometrów LSFO
PublicationOpisano sposób produkcji bolometrów wykorzystujących ceramiczne, przewodzące warstwy typu perowskitu z niestechiometrycznych tlenków lantanowo-strontowo żelazowych (LSFO) wykonanych technologią LTCC (Low Temperature Co-fired Ceramics). Zaprezentowano wyniki pomiarów parametrów tych bolometrów oraz pozwalające na wybór optymalnych warunków pracy.
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Stanowisko do pomiaru termicznej stałej czasowej bolometrów
PublicationPrzedstawiono stanowisko umożliwiające pomiar termicznej stałej czasowej bolometrów. Stanowisko to składa się z dwóch układów pomiarowych połączonych z cyfrowym analizatorem sygnału i umożliwia pomiar stałej czasowej w zakresie od pojedynczych milisekund do kilku sekund. Omówiono budowę i działanie opracowanych układów i zaprezentowano wyniki pomiarów stałej czasowej bolometrów z niestechiometrycznych tlenków lantanowo-strontowo-żelazowych...
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Low temperature broad band dielectric spectroscopy of multiferroic Bi6Fe2Ti3O18 ceramics
PublicationIn the present research the tool of broadband dielectric spectroscopy was utilized to characterize dielectric behavior of Bi6Fe2Ti3O18 (BFTO) Aurivillius-type multiferroic ceramics. Dielectric response of BFTO ceramics was studied in the frequency domain (Δν=0.1Hz – 10MHz) within the temperature range ΔT=-100°C – 200°C. The Kramers-Kronig data validation test was employed to validate the impedance data measurements and it was found...
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Evaluation of Low Temperature Properties of Rubberized Asphalt Mixtures
PublicationThe paper presents low-temperature test results of asphalt mixtures designed with use of bitumen modified by crumb rubber and also SBS polymer. Laboratory tests were conducted on two types of asphalt mixtures for wearing course – stone matrix asphalt (SMA 8) and porous asphalt (PA 8). This paper presents results of the following laboratory tests at low temperatures: TSRST test, three point bending creep test, fracture toughness...
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Proton Conducting Ceramic Powder Synthesis by a Low Temperature Method
PublicationMolten salt synthesis (MSS) is a simple method for the preparation of ceramic powders with specific morphology. The main role of the molten salts is to increase the reaction rate and lower the reaction temperature. It occurs because of much higher mobility of reactants in the liquid medium than in the solid state. In this work the molten salt synthesis was applied to produce ceramic powders of La0995Ca0005NbO4 and BaCe09−xZrxY01O3....
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Impact of low-temperature sintering on the Fe-based amorphous coatings
PublicationBulk metallic glasses (BMGs) have gained a lot of attention in recent years due to their outstanding properties such as high hardness and excellent wear and corrosion resistance. However, they are restricted in industrial applications due to their extreme brittleness. Iron based amorphous coatings from BMGs are the best solution to use them by overcoming the problem of extreme brittleness. The coatings can be sprayed by various...
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Influence of the low ambient temperature on the start-up process of hydraulic pumps
PublicationStarting hydraulic pumps in low ambient temperatures may cause: decreased hydraulic-mechanical efficiency, larger vibration of hydraulic installation, faster wear and more frequent damage to the elements of pumps, change of material properties of elements, increase of pressure drop. As a result of pressure drop in the suction pipe, large underpressure may be experienced, causing incomplete filling of pump working chambers with...
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Field Evaluation of High Modulus Asphalt Concrete Resistance to Low-Temperature Cracking
PublicationHigh-modulus asphalt concrete has numerous advantages in comparison to conventional asphalt concrete, including increased resistance to permanent deformations and increased pavement fatigue life. However, previous studies have shown that the construction of road pavements with High Modulus Asphalt Concrete (HMAC) may significantly increase the risk of low-temperature cracking. Those observations were the motivation for the research...
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Evaluation of Asphalt Mixture Low-Temperature Performance in Bending Beam Creep Test
PublicationLow-temperature cracking is one of the most common road pavement distress types in Poland. While bitumen performance can be evaluated in detail using bending beam rheometer (BBR) or dynamic shear rheometer (DSR) tests, none of the normalized test methods gives a comprehensive representation of low-temperature performance of the asphalt mixtures. This article presents the Bending Beam Creep test performed at temperatures from −20...
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Low temperature rotary Stirling engine: conceptual design and theoretical analysis
PublicationThe use of low-temperature energy sources for electricity generation demands a dual focus: a substantial enhancement in the efficiency of energy conversion devices and a reduction in system production costs. Particularly in scenarios where low-temperature energy sources are scarce, this factor can be pivotal in facilitating widespread adoption of such technologies. The Stirling engine emerges as a promising solution capable of...
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Dissolution of Nb-doped hydroxyapatite prepared via low-temperature mechanochemical method: Spectroscopy studies
PublicationCalcium phosphate glass ceramics with nominal hydroxyapatite stoichiometry doped with niobium were synthesized using simple as well as low-temperature mechanochemical method and then in the form of compressed pellet were submitted to the static dissolution process in distilled water for one month. The results of structural analysis, performed mainly on the base of spectroscopic methods such as: infrared absorption spectroscopy,...
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Analysing selection of low-temperature medium for cogeneration micro power plant
PublicationThe article analyses the ORC system working with dry and wet low-boiling media which are most frequently used in installations of this type. Two types of cycles were examined, which were the cycle with heat regeneration for dry media: fc72, hfe7100, R227ea, R245fa, R423a and R600a, and the cycle without heat regeneration for wet media: R11, R12, R134a, R718 and 507a. The calculations were performed for the assumed required thermal...
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Analysing selection of low-temperature medium for cogeneration micro power plant
PublicationThe article analyses the ORC system working with dry and wet low-boiling media which are most frequently used in installations of this type. Two types of cycles were examined, which were the cycle with heat regeneration for dry media: fc72, hfe7100, R227ea, R245fa, R423a and R600a, and the cycle without heat regeneration for wet media: R11, R12, R134a, R718 and 507a. The calculations were performed for the assumed required thermal...
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Low-Temperature Requirements for Bitumen in Central East European Road Construction
PublicationThe paper presents the proposition of special assessment of lowtemperature requirements for bitumens in the region of Central and Eastern Europe where there is a moderate transitional area from sea to the continental type of climate. The results of the research program conducted on the road neat bitumens, Styrene-Butadiene-Styrene polymer and polymer-rubber modified bitumen, and multigrade bitumen types were presented and discussed....
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Influence of cooling rate and additives on low-temperature properties of asphalt mixtures in the TSRST
PublicationThe paper presents the results and analysis of low-temperature properties of asphalt mixtures according to Thermal Stress Restrained Specimen Test (TSRST) and Indirect Tensile Test methods. Different groups of bitumen were investigated: neat, SBS-modified and highly SBS-modified. Influence of cooling rates (1 C/h, 3 C/h, 5 C/h and 10 C/h) and additives (aramid fibres and crumb rubber) was identified as well. Moreover, for each...
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Management of low-temperature heat source by ORC aided by additional heat source
PublicationThe presented work is aimed at utilisation of waste heat in the manner to produce electricity in ORC installation. Therefore the precondition of the study was to use the waste heat available in the form of a stream of hot water at 90°C. Such low enthalpy heat source is rather insufficient to produce a good quality vapour to feed the ORC turbine. That was the incentive to search for the ways of increasing the temperature of the...
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Management of low-temperature heat source by ORC aided by additional heat source
PublicationIn the paper presented is a concept to utilize waste heat from the power plant with the aid of the low-temperature ORC cycle. The ORC system is heated from two heat sources, the first one being the flow rate of waste heat obtained from the exhaust gases. Subsequently, the working fluid in the cycle is additionally heated by the condensing steam from the low pressure turbine extraction points increasing in such way the level of...
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The Influence of Low-Temperature Disintegration on the Co-Fermentation Process of Distillation Residue and Waste-Activated Sludge
Publication: Innovative low-temperature disintegration (process temperature 55 ◦C and oxygen concentration 0.2 mg/dm3 ) can be an economically rational technology to intensifying energy production from renewable sources. The proposed process can achieve a degree of disintegration—under optimal conditions—of about 50%, which is excellent when compared with other methods of feed pre-treatment. The low-temperature disintegration of distillation...
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Testing of low temperature behaviour of asphalt mixtures in bending creep test
PublicationThe paper presents a method of bending beam test and its importance for evaluation of asphalt mixtures behaviour at low temperatures. Two types of asphalt mixtures: asphalt concrete AC with normal paving grade bitumen and stone mastic asphalt SMA with SBS-modified bitumen were tested. Long-term oven ageing (LTOA) test was also used in the laboratory according to SHRP procedure. The Burgers model was applied and rheological parameters...
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Field investigation of low-temperature cracking and stiffness moduli on selected roads with conventional and high modulus asphalt concrete
PublicationHigh Modulus Asphalt Concrete (HMAC) was introduced in Poland as a one of the solutions to the problem of rutting, type of deterioration common in the 1990s. After first encouraging trials in 2002 HMAC was widely used for heavily loaded national roads and motorways. However some concerns were raised about low-temperature cracking of HMAC. This was the main reason of the studies presented in this article were started. The article...
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Effect of austempering temperature on microstructure and cyclic deformation behaviour of multiphase low-carbon steel
PublicationThis paper examined the cyclic deformation behaviour of multiphase low-carbon steel that was subjected to austempering heat treatments at four temperatures (190 °C, 230 °C, 275 °C, and 315 °C) below the martensite start temperature (Ms = 353 °C). The tests were conducted at room temperature, under fully reversed strain-controlled conditions, with strain amplitudes in the range 0.5–1.0%. The microstructure was observed by transmission...
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Comparison of low-temperature cracks intensity on pavements with high modulus asphalt concrete and conventional asphalt concrete bases
PublicationHigh modulus asphalt concrete (HMAC) base courses provide very good resistance to rutting and fatigue but they can increase the risk of low-temperature cracking as compared with conventional asphalt concrete (AC). The article presents the comparison of these two road materials in terms of low-temperature cracking. The statistical method based on the ordered logistic regression model was used. The analysis was based on results of...
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Characteristics of LaCo 0.4 Ni 0.6-x Cu x O 3-δ ceramics as a cathode material for intermediate-temperature solid oxide fuel cells
PublicationIn this study, the effects of Cu-ion substitution on the densification, microstructure, and physical properties of LaCo0.4Ni0.6-xCuxO3-δ ceramics were investigated. The results indicate that doping with Cu ions not only enhances the densification but also promotes the grain growth of LaCo0.4Ni0.6-xCuxO3-δ ceramics. The Cu substitution at x ≤ 0.2 can suppress the formation of La4Ni3O10, while the excess Cu triggers the formation...
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PROBLEMS OF THE STARTING AND OPERATING OF HYDRAULIC COMPONENTS AND SYSTEMS IN LOW AMBIENT TEMPERATURE (PART IV) MODELLING THE HEATING PROCESS AND DETERMINING THE SERVICEABILITY OF HYDRAULIC COMPONENTS DURING THE STARTING-UP IN LOW AMBIENT TEMPERATURE
PublicationDesigners of hydraulically driven machines and devices are obliged to ensure during design process their high service life with taking into account their operational conditions. Some of the machines may be started in low ambient temperature and even in thermal shock conditions (due to delivering hot working medium to cold components). In order to put such devices into operation appropriate investigations, including experimental...
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The low temperature waste heat recovery in drying process of pine wood using micro-jet heat exchanger
PublicationThe article presents the influence of the drying medium temperature changes for the relative and absolute moisture content values during pine wood drying. The drying process was conducted at constant atmospheric pressure and with different drying medium (air) temperature levels, respectively: 40oC, 60oC, 80oC, 100oC, and 120oC. In order to develop a method that would enable low temperature drying of solid materials the experiments...
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Impact of reclaimed asphalt pavement (RAP) on low-temperature properties of asphalt concrete
PublicationHot mix recycling is a practice which enables reusing materials from old asphalt pavements. Current Polish regulations allow usage of RAP only for binder and base courses, and its amount is limited. Asphalt mixtures with RAP material have to fulfil requirements stated for typical asphalt mixtures. The research presents low-temperature properties of twelve different asphalt concretes with RAP material, determined using three-point...
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Modeling of low calorific gas burning in a deficient oxygen environment and high-temperature oxidizer
PublicationThe experimental research will be performed using the experimental facility with a combustion chamber. The oxygen concentration in combustion oxidizers will be varied from 21% by volume (normal) air to 2%. The test combustion chamber will be fed with propane or methane as the reference fuel, then with low calorific fuels as test gases obtained by mixing various combustible components, e.g. H2, CH4, CO, and neutral gases, e.g. N2,...
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Low temperature luminescence of KMgF3:Eu2+ crystal
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Low-temperature high-pressure cryogelation of nanooxides
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The Impact of Homogeneity of High Modulus Asphalt Concrete Layer on Low-Temperature Cracking
PublicationDuring winter season of 2012 numerous transverse cracks developed in high-modulus asphalt concrete (HMAC) base of newly constructed motorway. Pavement cracked both in transverse joint locations and in the area between them. Research which was conducted during investigation of the causes and mechanisms of cracking consisted of: field examination, laboratory testing of specimens cored out of the existing pavement, computational analyses...
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Asphalt concrete subjected to long-time loading at low temperatures – Deviations from the time-temperature superposition principle
PublicationThe article presents the observed deviations from the time-temperature superposition principle of asphalt concretes, tested in the bending beam creep test at low temperatures for a long time of loading. In almost all tested asphalt concretes, deviations appeared after 500 s of loading at the temperature of -10 C. Some types of bitumen presented deviations at other temperatures – usually the harder the grade of the bitumen, the...
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Effect of bitumen characteristics obtained according to EN and Superpave specifications on asphalt mixture performance in low-temperature laboratory tests
PublicationThe paper aims to identify those characteristics of bitumen which have the greatest impact on asphalt mixture low-temperature performance. It was observed that stiffness and m-value of bitumen from BBR test were moderately related to stiffness and m-value of asphalt mixture obtained from 3 PB test. Simultaneously those rheological properties significantly impact on cryogenic stresses induced during TSRST test. The multiple regression...
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Sestaveni Smerne Krivky Modulu Tuhosti Pro Zkoumani Nizkotrplotnich Vlastnosti (Developing of Stiffness Master Curve for Analysis of Low Temperature Properties)
PublicationV prispevku je predstaven novy postup pro sestrojeni smernych tuhostnich krivek. Nizkoteplotni vlastnosti asfaltove smesi byly stanoveny za vyuziti zkousky dotvarovani pri tribodovem ohybu. Motivem tohoto vyzkumu je skutecnost, ze metody hodnoceni nizkoteplotniho chovani asfaltovych smesi, nove zavedenych v Polsku, nejsou dostatecne. V zaveru jsou prezentovany smerne krivky tuhosti beznych asfaltovych smesi vyuzivanych v Polsku.
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Fatigue life improvement using low transformation temperature weld material with measurement of residual stress
PublicationWelding processes often produce high levels of tensile residual stress. Low transformation temperature (LTT) welding wires utilise phase transformation strains to overcome the thermal contraction of a cooling weld. In this paper, the residual stress within each weld was quantified using the milling/strain gauge method, being the strain change measured as the weldment was milled away. The fatigue tests were conducted under uniaxial...
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Biochemical assays of intensified methane content in biogas from low-temperature processing of waste activated sludge
PublicationAnaerobic digestion (AD) is implemented as an important ‘waste to energy’ approach for converting organic-rich byproducts such as sewage sludge into biogas and nutrient-rich digestate. Sewage sludge consists of primary sludge and waste activated sludge (WAS), and low biodegradability of WAS limits methane production. This study presents the influence of the low-temperature pretreatment (LT-PT) of WAS on the efficiency of AD. Different...
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Influence of Bitumen Type and Asphalt Mixture Composition on Low-Temperature Strength Properties According to Various Test Methods
PublicationIn regions with low-temperatures, action transverse cracks can appear in asphalt pavements as a result of thermal stresses that exceed the fracture strength of materials used in asphalt layers. To better understand thermal cracking phenomenon, strength properties of different asphalt mixtures were investigated. Four test methods were used to assess the influence of bitumen type and mixture composition on tensile strength properties...
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Criteria for selection of working fluid in low-temperature ORC
PublicationThe economics of an ORC system is strictly linked to thermodynamic properties of the working fluid. A bad choice of working fluid could lead to a less efficient and expensive plant/generation unit. Some selection criteria have been put forward by various authors, incorporating thermodynamic properties, provided in literature but these do not have a general character. In the paper a simple analysis has been carried out which resulted...
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Factors affecting low-temperature cracking of asphalt pavements: analysis of field observations using the ordered logistic model
PublicationAccurate identification of factors that primarily affect the number of low-temperature cracks is crucial for selection of road materials and planning of pavement maintenance. Field investigations of lowtemperature cracks were performed in the years 2014 and 2020 on the same 68 road sections being in service in typical traffic conditions. The collected data were statistically analysed using the ordered logistic regression model....
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Effect of pyrolysis temperature on the microstructure and thermal conductivity of polymer-derived monolithic and porous SiC ceramics
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Low temperature growth of diamond films on optical fibers using Linear Antenna CVD system
PublicationIt is not trivial to achieve a good quality diamond-coated fibre interface due to a large difference in the properties and composition of the diamond films (or use coating even) and the optical fibre material, i.e. fused silica. One of the biggest problems is the high temperature during the deposition which influences the optical fibre or optical fibre sensor structure (e.g. long-period gratings (LPG)). The greatest advantage of...
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Utilisation of bleed steam heat to increase the upper heat source temperature in low-temperature ORC
PublicationW pracy przedstawiono możliwość dogrzewu obiegu ORC za pomocą pary upustowej.
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Comparison of traditional district heating with low temperature district heating systems featuring organic Rankine cycle and heat pump
PublicationPaper presents a comparison between a traditional district heating system with conventional boilers as a source of heat and electricity purchases from power utilities and a low temperature DH system incorporating the CHP with organic Rankine Cycle providing electricity and local heat pump raising the temperature of the DH fluid to the required temperature in the dwelling, meaning that both heat and electricity are produced within...
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Low-temperature spectroscopic and scintillation characterisation of Ti-doped Al2O3
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Low-temperature reactivity of the surface species of vanadia–tungsta catalyst
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Low-temperature synthesis of silicon carbide powder using shungite
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Mitigation of Membrane Wetting by Applying a Low Temperature Membrane Distillation
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Fiber-optic temperature sensor using low-coherence interferometry
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Low-temperature processing of thin-film electrolyte for electrochemical devices.
PublicationPrzygowanie filmów elektrolitu jest jednym z najbardziej istotnych procesów technologicznych wytworzenia urządzeń elektrochemicznych takich jak ogniwa paliwowe. Zmniejszenie grubości filmu jest powiązane ze zmniejszeniem rezystancji elektrolitu, co bardzo korzystnie wpływa na wydajność ogniw paliwowych. W pracy tej przedstawiono niskotemperaturową (<1000C) metodę wytwarzenia filmów elektrolitu z tlenku cyrkonu stabilizowanego itrem...