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Wyświetlanie 1-15 z 219
Tytuł:
Studies on development of an electrothermal method of measuring the soil thermal conductivity
Autorzy:
Stawicki, J.
Opydo, W.
Powiązania:
https://bibliotekanauki.pl/articles/97718.pdf
Data publikacji:
2012
Wydawca:
Politechnika Poznańska. Wydawnictwo Politechniki Poznańskiej
Tematy:
thermal conductivity
soil thermal conductivity
Statistica
Opis:
The paper presents the studies on development of a simplified electrothermal method of measuring the soil thermal conductivity, that may be used directly in the field. A measurement system has been designed and built, that is connected to measuring sensors located in the examined soil. Two types of sensors, i.e. active and passive ones were used. The passive sensors were provided with thermistors used for temperature measurement, while the active one, apart from the thermistor, was provided with a heating element of resistance type. The study has shown that the proposed method, consisting in measuring the steady heat conduction between the measuring sensor and soil, allows to determine the value of the soil thermal conductivity with satisfying accuracy. Moreover, the method is conducive to significantly smaller disturbance of the soil structure, being a reason of measurement errors occurring while using traditional methods. Mathematical processing of the research results has been carried out with the help of STATISTICA software.
Źródło:
Computer Applications in Electrical Engineering; 2012, 10; 118-126
1508-4248
Pojawia się w:
Computer Applications in Electrical Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Measurements of a steel charge emissivity under strong irradiance conditions
Autorzy:
Benduch, A.
Wyczółkowski, R.
Powiązania:
https://bibliotekanauki.pl/articles/102336.pdf
Data publikacji:
2014
Wydawca:
Stowarzyszenie Inżynierów i Techników Mechaników Polskich
Tematy:
porous charge
thermal radiation
thermal resistance
long elements bundles
effective thermal conductivity
radiative thermal conductivity
Opis:
Steel bars are manufactured in the rolling process, whereby they are characterized by strain hardening and poor plastic properties. In many application cases such properties are improper, therefore, additional heat treatment is required. Crucial influence on the products quality after heat treatment has an appropriate selection of process parameters. In many modern technologies of heat treatment the charge of porous structure is subjected to the heating process. Proper control of heat treatment parameters of bundles of rods requires knowledge on their thermal properties. However, it also requires accurate identification of complex heat transfer processes occurring in the porous material. Such analysis, with respect to bundles of bars, provide a response of qualitative nature of the heat exchange area of these charges. The article describes the emissivity measurements of samples of the steel charge using a thermal imaging camera.
Źródło:
Advances in Science and Technology. Research Journal; 2014, 8, 23; 19-25
2299-8624
Pojawia się w:
Advances in Science and Technology. Research Journal
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The impact of graphite impact on the thermal conductivity of the solidified grout
Autorzy:
Śliwa, T.
Kowalski, T.
Stryczek, S.
Wiśniowski, D.
Bieda, A.
Piwowarczyk, S.
Beszłej, J.
Naklicki, M.
Sapińska-Śliwa, A.
Powiązania:
https://bibliotekanauki.pl/articles/298729.pdf
Data publikacji:
2017
Wydawca:
Akademia Górniczo-Hutnicza im. Stanisława Staszica w Krakowie. Wydawnictwo AGH
Tematy:
graphite
thermal conductivity
geothermal energy
Opis:
The fast development of low-temperature geothermal energy affects the search for newer and newer solutions and materials used in the construction of borehole heat exchangers. One of the most important factors affecting the correct operation of heat pump systems with borehole heat exchangers is appropriately selected solidified grout. Solidifies grout has to be characterized by the highest thermal conductivity and good sealing borehole heat exchangers. The paper will present the impact of graphite on the thermal conductivity of solidified grout.
Źródło:
AGH Drilling, Oil, Gas; 2017, 34, 4; 811-820
2299-4157
2300-7052
Pojawia się w:
AGH Drilling, Oil, Gas
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Investigation of heating time of a bundle of steel bars
Badanie czasu nagrzewania wiązki prętów stalowych
Autorzy:
Aghbalyan, S.
Bagdasaryan, V.
Wyczółkowski, R.
Powiązania:
https://bibliotekanauki.pl/articles/28766072.pdf
Data publikacji:
2022
Wydawca:
Szkoła Główna Gospodarstwa Wiejskiego w Warszawie. Wydawnictwo Szkoły Głównej Gospodarstwa Wiejskiego w Warszawie
Tematy:
steel bar
heating time
thermal conductivity
effective thermal conductivity
energy balance
heat treatment
process optimization
Źródło:
Acta Scientiarum Polonorum. Architectura; 2022, 21, 3; 25-30
1644-0633
Pojawia się w:
Acta Scientiarum Polonorum. Architectura
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Investigation of Thermal and Mechanical Properties of Three-Dimensional Braided Composite Materials
Autorzy:
Arbaoui, Jamal
Aucher, Jérémie
Gomina, Moussa
Breard, Joel
Powiązania:
https://bibliotekanauki.pl/articles/2174567.pdf
Data publikacji:
2022
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
braided composites
thermal conductivity
bending
tensile
Opis:
This paper investigates the thermal and mechanical properties of a composite made from a combination of 2063-epoxy resin and three different braided carbon-fiber fabric reinforcements. These fibres consist of HTS carbon, HTS carbon braided with nickel coated carbon and HTS carbon braided with nickel coated copper, respectively. The composites were manufactured through resin transfer molding (RTM) route. The thermal diffusivity of carbon fibers composites was measured at different temperature by using a flash method. The transverse and planar thermal conductivities were determined by measuring the specific heat, density and thermal diffusivities, respectively. The current research highlights the influence of adding nickel coated carbon and nickel-plated copper wires on the braided composites. The evaluation shows that the HTS carbon braided manufactured with nickel-plated copper wires presents higher in-plane thermal conductivity (in direction parallel of the fibres) when comparing to HTS carbon and HTS carbon braided manufactured with nickel coated carbon. The thermal conductivity benefits of those composite were achieved at the expenses of lower mechanical properties of braided composites investigated.
Źródło:
Archives of Metallurgy and Materials; 2022, 67, 4; 1325--1332
1733-3490
Pojawia się w:
Archives of Metallurgy and Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The energy parameters of formation of the porous structure
Autorzy:
Koshlak, H. V.
Pavlenko, A.
Piotrowski, J. Z.
Powiązania:
https://bibliotekanauki.pl/articles/402161.pdf
Data publikacji:
2016
Wydawca:
Politechnika Świętokrzyska w Kielcach. Wydawnictwo PŚw
Tematy:
thermal conductivity
porosity
swelling
heat insulation
Opis:
Research porosity thermal insulation of refractory materials is the important task of power engineering, because the thermal conductivity of porous materials depends on the shape and especially location of pore. Analytical review of existing technologies shows that research in this area is focused on the study of a process separately and generalized theories are not sufficient to clear analysis and model building process heat mass transfer of alumina porous material.
Źródło:
Structure and Environment; 2016, 8, 3; 206-210
2081-1500
Pojawia się w:
Structure and Environment
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The Effect of Using Naphthalene and Local Soil with Concrete Mixture on Thermal Conductivity, Case of Mafraq City – Jordan
Autorzy:
Alzoubi, Hussain H.
Al-Olaimat, Duha J.
Powiązania:
https://bibliotekanauki.pl/articles/125324.pdf
Data publikacji:
2019
Wydawca:
Polskie Towarzystwo Inżynierii Ekologicznej
Tematy:
naphthalene
thermal conductivity
compressive strength
silica
Opis:
This study explores the effect of direct incorporation of different ratios of naphthalene with soil into the concrete used in Mafraq-Jordan on the thermal conductivity of concrete mixtures. The methodology involved testing 72 concrete cube samples. The basic samples were prepared only from a mixture of water, silica sand, and cement without additives. The additives of local soil and naphthalene of different ratios: 2.5%, 5%, 7%, 10% and 15%, were added to the tested samples. The samples were classified into two groups in terms of size and dimensions; 36 cubes with 5×5×5 cm were tested only for thermal conductivity, and 36 cubes with 3×3×3 cm were tested for compressive strength and thermal conductivity. All samples were tested after 28 days of casting, according to the concrete standards. The results show that adding naphthalene and soil to the cementitious mixtures substantially decreases the thermal conductivity of concrete elements. A reasonable reduction in thermal conductivity was achieved compared with the basic case samples. However, the compressive strength of samples remained within the acceptable values from the stand point of structural engineering. This enhancement in the thermal properties of concrete can be applied in building systems as concrete blocks used in internal and external walls.
Źródło:
Journal of Ecological Engineering; 2019, 20, 4; 42-53
2299-8993
Pojawia się w:
Journal of Ecological Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The temperature and stress field of the ceramic-capped cylinder head of the hypothetical adiabatic diesel engine
Autorzy:
Jaskólski, J.
Krzyżak, R.
Powiązania:
https://bibliotekanauki.pl/articles/241933.pdf
Data publikacji:
2008
Wydawca:
Instytut Techniczny Wojsk Lotniczych
Tematy:
cylinder head
PtAu alloy
thermal conductivity
thermal stress
Opis:
Four of five models of the ceramic-slab-capped cast-iron cylinder head for a prospective adiabatic engine were numerically investigated. The models were designed using several crystallochemical-mineralogical considerations. The outcome of some short radiation and convection Fortran95 programmes became the input data for the FEM programme of temperatures and stresses. It turns out, that in general the material that cannot withstand will hardly be ceramics, but the cast iron. Thence, the latter should be replaced, plated or the ceramics should cover it at the injection jet. The temperatures and stresses were analysed with and without an interlayer. Two models, with feldspars and Ti6Al4V or Pt30Au70, were quite promising, the first one being surely at once applicable even without interlayer i.e. according to FEM. The stresses in the models with YSZ, cerium disilicide and/or pyroxene, in spite of the crystallochemical hattrics deemed successful, betoken spallation of the YSZ. The problems of emissivity were addressed as well. There exists a blank range of temperature where neither radiation-related algorithm nor the common conductivity one can perform well. The surface of the head under hood appears 'quite cold', except the exhaust pipe, the TBC solution of which is left in abeyance in this paper. Adiabatic engines using ceramic as the material for the combustion camber walls were developed for the reduction of cooling loss and the in crease of exhaust energies.
Źródło:
Journal of KONES; 2008, 15, 4; 635-640
1231-4005
2354-0133
Pojawia się w:
Journal of KONES
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Physical Characteristics of Aceh Traditional Salt and Its Potential as Raw Material for Thermal Energy Storage
Autorzy:
Gunawati, -
Humaidi, Syahrul
Setiawan, Adi
Sirait, Makmur
Jalil, Zulkarnain
Ramadhani, Nadilla
Makruf, Amar
Riskina, Shafira
Irhamni, -
Powiązania:
https://bibliotekanauki.pl/articles/2026731.pdf
Data publikacji:
2022
Wydawca:
Polskie Towarzystwo Inżynierii Ekologicznej
Tematy:
aceh salt
enthalpy
thermal conductivity
thermal energy storage
Opis:
Thermal energy storage is an important element in order to conserve the energy and optimize the overall efficiency. Development of energy storage system for local purposes requires some information on the raw material which is abundantly available in the local market. This study aimed to investigate the characteristics of traditionally produced salt in Aceh in terms of its potential use as a raw material for thermal energy storage. The sample was collected from the Aceh Besar District and treated by heating at temperatures of 400 °C and 800 °C in a muffle furnace. This treatment is carried out to study the changes in properties and define the best procedure for salt preparation. All samples were characterized under a number of techniques including XRF, XRD, SEM/EDS, TGA/DSC analysis, density, thermal conductivity, and electrolytic conductivity. The XRF characterization showed that the local Aceh salt was graded as a category III salt. Furthermore, according to the TGA/DSC characterization, the melting temperature is close to 800 °C, and the enthalpy value is close to 492 kJ/kg. It is ample evidence that the Aceh salt can be used as a thermal energy storage material. Furthermore, increasing the temperature of local salt’s heat treatment contributes to increasing the enthalpy value, crystal size, density, thermal conductivity, and electrolyte conductivity.
Źródło:
Journal of Ecological Engineering; 2022, 23, 2; 116-122
2299-8993
Pojawia się w:
Journal of Ecological Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Influence of air humidity and temperature on thermal conductivity of wood-based materials
Autorzy:
Trochonowicz, Maciej
Galas, Monika
Powiązania:
https://bibliotekanauki.pl/articles/390811.pdf
Data publikacji:
2018
Wydawca:
Politechnika Lubelska. Wydawnictwo Politechniki Lubelskiej
Tematy:
wood-based materials
thermal conductivity coefficient
thermal insulation
Opis:
The aim of this paper is to approximate the issues related to the influence of air humidity and test temperature on the thermal conductivity coefficient λ of wood-based materials. During the laboratory tests, the λ coefficient was determined depending on the test temperature and air humidity, material density and sorption were also tested
Źródło:
Budownictwo i Architektura; 2018, 17, 4; 77-86
1899-0665
Pojawia się w:
Budownictwo i Architektura
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Thermal conductivity of food products
Przewodność cieplna produktów spożywczych
Autorzy:
Aerlichman, V.N.
Fatychov, J.A.
Kukelka, L.
Kopec, A.
Powiązania:
https://bibliotekanauki.pl/articles/35494.pdf
Data publikacji:
2014
Wydawca:
Polska Akademia Nauk. Instytut Agrofizyki PAN
Tematy:
food product
thermal conductivity
thermal diffusivity
thermal diffusivity coefficient
heat conductivity coefficient
Opis:
The presented work is focused on the food thermal characteristics calculation methods (heat conductivity coefficient and thermal diffusivity coefficient a). Thermal characteristics of food are important in food industry and define the intensiveness of technological processes of food refrigeration and thermal treatment, energy consumption for their realization and technological equipment production rate. They are also needed for the building and validation of mathematical models of heat transfer in food products which are useful in the design and optimisation of freezing, heating, cooking and cooling pro-cesses and equipment. It is not easy to define the food thermal characteristics. Difficulties arise from their heterogeneity, high labour consumption and complexity of experimental sets. Methods for experimental determination of heat conductivity coefficient and thermal diffusivity coefficient a based on the regular method mode require the α → ∞ condition, which is the case of high speed of the environment which flows around the test sample, as in the case of boiling or condensing. Using the method presented in this article it is possible to determine the heat conductivity and thermal diffusivity coefficient a even in the absence of the condition α → ∞.
W pracy opisano metodę pozwalającą na obliczeniowe wyznaczenie charakterystyk cieplnych produktów spożywczych – współczynnika przewodzenia ciepłaoraz współczynnika wyrównania temperatury (dyfuzyjności cieplnej) a. Współczynniki te wpływają na przebieg procesów obróbki termicznej produktów, a także na zużycie energii i produktywność urządzeń technologicznych. Znajomość tych współczynników jest konieczna do tworzenia modeli matematycznych wymiany ciepła w produktach spożywczych, użytecznych w projektowaniu i optymalizacji procesów i urządzeń do mrożenia, ogrzewania, gotowania czy schładzania produktów. Określenie właściwości cieplnych żywności nie jest łatwe. Trudności wynikają z różnorodności produktów spożywczych, pracochłonności i złożoności stanowisk badawczych. Sposoby eksperymentalnego wyznaczania ww. współczynników oparte na metodzie stanu uporządkowane-go wymagają spełnienia warunku α→∞, co ma miejsce w przypadku dużych prędkości środowiska omywającego badaną próbkę, przy gotowaniu lub kondensacji. Za pomocą przedstawionej w pracy metody możliwe jest wyznaczenie współczynnika przewodzenia ciepła i współczynnika dyfuzyjności cieplnej a nawet w przypadku braku spełnienia warunku α→∞.
Źródło:
Acta Agrophysica; 2014, 21, 2
1234-4125
Pojawia się w:
Acta Agrophysica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Investigation on performance of diesel engine using Al2O3 nanofluid as coolant
Autorzy:
Rambabu, V.
Sai Chaitanya, P.
Prasad Rao, K.
Powiązania:
https://bibliotekanauki.pl/articles/102514.pdf
Data publikacji:
2017
Wydawca:
Stowarzyszenie Inżynierów i Techników Mechaników Polskich
Tematy:
coolants
ethylene glycol
nanofluids
thermal conductivity
water
Opis:
Water and ethylene glycol as ordinary coolants have been broadly utilized as a part of a car radiator for a long time. These heat exchange liquids offer low thermal conductivity. With the progression of nanotechnology, the new era of heat transfer fluids called, “nanofluids” have been developed and analysts found that these liquids offer higher thermal conductivity contrasted with that of routine coolants. This study concentrated on the utilization of a mixture of water and ethylene glycol based Al2O3 nanofluids in a cooling framework. Pertinent information, nanofluid properties and exact connections were obtained from literature review to examine the performance of a twin cylinder Diesel engine under various blends of nanofluid based coolants, furthermore, to research heat exchange improvement of a car radiator worked with nanofluid-based coolants. It was observed that, the performance of Diesel engine and heat transfer rate in cooling system framework enhanced with the utilization of nanofluids (with water and ethylene glycol the basefluid) contrasted with water and ethylene glycol (i.e. base liquid) alone. In the wake of leading the series of tests on Twin cylinder Diesel engine at 2%, 1% and 0.5% of nanofluid in basefluid, it was observed that performance of Diesel engine and heat exchange is upgraded better at 0.5% of Al2O3 nanofluid coolant.
Źródło:
Advances in Science and Technology. Research Journal; 2017, 11, 2; 58-64
2299-8624
Pojawia się w:
Advances in Science and Technology. Research Journal
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Analysis of the distribution of temperature and humidity in different variants of external walls made of hemp-lime composite
Autorzy:
Alberska, A.
Brzyski, P.
Powiązania:
https://bibliotekanauki.pl/articles/390453.pdf
Data publikacji:
2017
Wydawca:
Politechnika Lubelska. Wydawnictwo Politechniki Lubelskiej
Tematy:
condensation
thermal conductivity
moisture
industrial hemp
lime
Opis:
Proper design of the building component, which not only meets the legal requirements, but also provides comfort of using of buildings, requires knowledge of the materials and solutions. Since moisture is one of the main factors that can affect the building structure destruction, it is particularly important to be aware of hygrothermal properties of components. And this is the focus of the study. In this paper several variants of external walls were analysed, according to the requirements in terms of: heat transfer coefficient U, the risk of surface and interstitial condensation. Partitions were designed with composite based on shives from industrial hemp and lime binder, which is not yet widely used in Poland. The purpose of the analysis of this material was to prove the validity of using the natural materials in residential buildings.
Źródło:
Budownictwo i Architektura; 2017, 16, 2; 141-151
1899-0665
Pojawia się w:
Budownictwo i Architektura
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Fire Resistance of Timber Joints with Steel Fasteners
Autorzy:
Domański, T.
Kmiecik, K.
Powiązania:
https://bibliotekanauki.pl/articles/105572.pdf
Data publikacji:
2018
Wydawca:
Politechnika Rzeszowska im. Ignacego Łukasiewicza. Oficyna Wydawnicza
Tematy:
thermal conductivity
fire safety
connections
elevated temperatures
Opis:
Fire safety is a major concern in the design of timber construction. Wood is combustible material. The thermal response of timber connections is usually the main factor in evaluating the overall load-bearing capacity of wood structures exposed to fire. The analysis of timber joints under fire conditions is difficult and complex. Finite element model is developed to predict the thermal behavior of bolted wood-to-wood joints exposed to fire. In fire, the material characteristic depend on the temperature. The thermal model is continuous, taking into account the thermal continuity between the joint components. Also, the thermal model is used to predict the evolution of the temperature field inside the connection. The paper presents a summary of results from a numerical studies of the fire behavior of wood-to-wood timber connections with steel bolt. As a result of computer simulations the temperature distribution was obtained. During fire exposure, the timber section is reduced and steel bolt reduces strength. Loadcarrying capacity per shear plane in fire conditions was calculated using two methods: design methods according to EN 1995-1-1 [5] and reduced load method according to EN 1995-1-2 [6]. In the first approach, the timber section loss and steel strength reduction during the fire were taken into account.
Źródło:
Czasopismo Inżynierii Lądowej, Środowiska i Architektury; 2018, 65, 2; 81-90
2300-5130
2300-8903
Pojawia się w:
Czasopismo Inżynierii Lądowej, Środowiska i Architektury
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Effect of heat transfer on thermal stresses in an annular hyperbolic fin: an approximate analytical solution
Autorzy:
Mallick, A.
Ranjan, R.
Sarkar, P. K.
Powiązania:
https://bibliotekanauki.pl/articles/279437.pdf
Data publikacji:
2016
Wydawca:
Polskie Towarzystwo Mechaniki Teoretycznej i Stosowanej
Tematy:
thermal stresses
Adomian decomposition method (ADM)
variable thermal conductivity
Opis:
An approximate analytical solution is presented for thermal stresses in an annular convectiveconductive fin of a hyperbolic profile with temperature dependent thermal conductivity. The classical thermo-elasticity theory coupled with the ADM based polynomial form of temperature field is employed for an approximate analytical solution of thermal stresses. The influence of thermal parameters, i.e. variable thermal conductivity, the thermo-geometric parameter and the non-dimensional coefficient of thermal expansion on temperature and sttress fields are investigated. The results for the stress field obtained from the ADM based solution are compared with those available in literature and found to be in close agreement.
Źródło:
Journal of Theoretical and Applied Mechanics; 2016, 54, 2; 437-448
1429-2955
Pojawia się w:
Journal of Theoretical and Applied Mechanics
Dostawca treści:
Biblioteka Nauki
Artykuł
Wyświetlanie 1-15 z 219

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