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Buildings account for almost 40% of total energy use, in the European Union. Energy losses in this sector should be reduced. To reach this, thermal insulation of buildings is a key solution. Polystyrene insulations are ordinary, and their thermal properties are well known. However, the most promising type is the graphite enhanced one with relatively less information. These graphite doped material products have much better thermal insulation properties than the conventional (white) ones. This paper will present measurements of sorption isotherms, combined with kinetic vapour experiments performed in a climatic chamber. Based on the results, the identification of the sorption isotherm will be shown. Moreover, the other scope of the paper is to apply a theoretical model used for diffusion after immersion to calculate the vapour diffusion in the samples treated in a climatic chamber. Furthermore, grain size analysis will be executed from microscope images, too. [ABSTRACT FROM AUTHOR]

Currently, 3D printing is used in various industries from the production of prototypes to final products. From the point of view of sustainable development, materials based on polylactic acid (PLA) are suitable, for which it is possible to ensure controlled degradation. In terms of aesthetics, but also applicability, it is important to know the thermal properties of filaments, but also the final products with different types of additives. In the present paper, PLA samples with various pigments and conductive materials are studied. The transient step wise method was used to study the thermal properties. This method allows determining all three basic thermal parameters (thermal conductivity λ, specific heat capacity cp, and thermal diffusivity a). It was found that for samples with pigments, these parameters were in the range of values λ=(0.15 – 0.25) W/m/K, cp=(900 – 1100) J/kg/K, and a ≈ 0.15 mm2/s. For samples with electrically conductive admixtures, are the equivalent parameter in range λ=(0.22 – 0.30) W/m/K, cp=(400 – 600) J/(kg.K), a ≈ 0.17 mm2/s. It turned out that electrically conductive materials (PLA with metal admixtures) show a very good coefficient of thermal conductivity and lower specific heat capacity, while materials with admixtures of pigments show a lower thermal conductivity and higher specific heat capacity. These materials we use, in present time, for construction of boxes for measuring thermal properties of low temperature PCM materials (up to 50 °C) and an electrode system for measuring the electrical properties of thin film semiconductors and crystals. [ABSTRACT FROM AUTHOR]

Since the 1990's, nanofluids have been one of the abundantly preferred newcomer technology invented to assist in electronic and heat transfer purposes. Their thermophysical properties and heat transfer performance make nanofluids highly demanded to overcome the current issues in the world. In this paper, a vast number of applications using nanofluids are reviewed as well as an epitome on the challenges in their respective areas. Additionally, recent research papers for specific applications of nanofluids in improving heat transfer efficiency were outlined while the experimental and theoretical methods were discussed in the articles and journals is summarized in this paper including the effects of thermal properties on the performance of nanofluids. In a nutshell, this review of experimental research extracted from most recent papers, published from 2011 to 2016, is a review on the latest updates in the nanofluids and heat transfer community to help anyone in concern of the topic and enough information to select nanofluids based on their needed applications. [ABSTRACT FROM AUTHOR]

The bio-wastes from the industries, households, and markets are often underutilized and usually accumulate at landfills. Though these fillers are inferior in properties compared to synthetic fillers, they can still be used as potential reinforcements for the polymer composites requiring low to moderate strength and stiffness. This article intends to discuss the influence of various types of fillers, physical characteristics such as size, aspect ratio of the filler, etc.,and % weight of the fillers on the thermal and mechanical properties of the composites reinforced with these fillers. It also aims to bring in the interfacial adhesion characteristics of the filler with the polymer matrix. The pioneering of bio-based composite materials in the automobile industry brings forth an impact on cost-effective and highly reliable materials. Biowaste from the industries, households, and markets was used as bio-fibersthat are used in the form of threads or also as fillers. This paper investigated the governing of bio-fillers effects on the mechanical and thermal properties of composite materials. The existence of bio-fillers exhibited improvement in both the strength and thermal stability of the composite materials. Filler influencewas based on weight percentage distinguished by the change in the strength of the composite materials due to the bonding and voids present in the composite materials that also affected the thermal firmness. This paper also discusses the characterization of fibers in terms of their constituents, strength, and thermal stability. These fillers influence the composite materials based on the different categories,such as (i) preparation process of fillers (ii) size of the fillers (iii) bonding of the fillers towards the matrix (iv)weight percentage of fillers, and (v) strength and thermal properties of fillers. This study also deals with the effect of hybridization of the composite materials by the presence of the fillers into the fiber-reinforced composite materials. Hence, the forthcoming study discusses the preparation of filler added composite materials, their mechanical and thermal properties of the composites. [ABSTRACT FROM AUTHOR]

Fiber-reinforced polymer composites have extended their discovery and application in a variety of industries, such as automobile, marine and aerospace. Polymer composite materials are used to protect the re-entry space vehicles from heat. Carbon fiber (Cf) composites based on polyacrylonitrile (PAN) reinforced along with phenolic resin (PR) are suitable for high-temperature thermal protection system (TPS). This paper describes the experimental evaluation of PAN-based carbon-phenolic composites for thermal protection system. The hand-layup approach was utilized to construct the Cf-PR composite laminates, with curing temperatures ranging from 120°C to 150°C and pressures ranging from 80 to 100 kg/cm2 for four hours under a hydraulic hot compression machine. The prepared composites were characterized by, interlaminar shear strength (ILSS) and flexural strength, compression strength, bar coal hardness, thermal conductivity, and density tests. The Cf-PR developed composites shown good thermo-mechanical properties for the application of TPS. [ABSTRACT FROM AUTHOR]

Cellulose is the most abundant biomass material in nature and has several promising properties. Interest in nanocrystalline cellulose (NCC) has increased dramatically exponential because it is relatively easy to prepare in high yields, it is strong, has a low weight, a high specific surface, thermal stability, and is biodegradable. NCC with a length ranging from 100 to 500 nm and a diameter of less than 10 nm, is a promising material because it can be applied in various fields, such as biomedicine, adsorbent, emulsifier, filler, and a composites. However, the hydrophilic properties of the NCC surface causes a the limited application because of its incompatibility with hydrophobic polymers. Therefore, various modifications to the surface of NCC have been investigated to increase the compatibility between NCC and hydrophobic matrix polymers. This paper summarizes several methods that can be used for surface modification of NCC, including cationization modification, acetylation, oxidation, carbamination, non-silane and its application resulted a better interaction with a hydrophobic polymer. The improved mechanical, barrier, water resistant and thermal properties have a positive effect when the NCC is used as reinforcement material. [ABSTRACT FROM AUTHOR]

This paper presents a short summery on the effect of the addition and doping of Sn-Ag-Cu or commonly known as SAC alloys with Aluminum oxide (Al2O3) nanoparticles. The paper introduce initially the background of the lead free solders as well as establish the concept of nanoparticle reinforcement composite lead free solder alloys. Then a short summery on the effect of the two nanoparticle reinforcement on the sac solder in the sections of Thermal properties and mechanical properties is presented. For instance some reported with Sn-0.3Ag-0.7Cu (SAC0307) when alloyed with 0.12 Al2O3 it showed an improved shear force of thermal cycling when it came to the mode of ductile fracture in comparison to the original alloy which possess a mode of fracture that presented a mixture between ductile and brittle. [ABSTRACT FROM AUTHOR]

Free flame combustion (open-air environment) and incomplete combustion of the air-fuel mixture in a conventional burner are the reason for the lower performance of the gaseous cookstove. So, need of the time is to develop a novel porous radiant burner using porous media combustion technology. This paper talks about the effects of burner configuration and operating parameters on the performance of the porous radiant burner. The porosity, geometry, thermal properties of porous media are responsible for improving flame stability, thermal efficiency, and reducing emission in the porous radiant burner. The equivalence ratio and thermal load are the two important controlling parameters in the porous radiant burner. The analysis in the porous radiant burner indicates an increase in thermal efficiency than conventional burners for various gaseous fuels. Emission analysis shows a significant reduction in the porous radiant burner than the conventional burner. This paper will help the research community to develop a new porous radiant burner which is the need of the future generation. [ABSTRACT FROM AUTHOR]

Cement composites exposed to high temperatures change their microstructure, composition and properties. In different temperature ranges, various physical and chemical processes take place in both their matrix and aggregates, which significantly affect the heat and mass transfer parameters, as well as the strength characteristics. In this paper, the effect of plasticizers on thermal properties of heat resistant composites based on calcium aluminate cement is studied. Thermal conductivity, specific heat capacity, and thermal strain are determined as a function of thermal load and compared with a reference material. The experimental results show that for the analyzed composites modified carboxylate is the most convenient choice while melamine-formaldehyde resin is found unsuitable. [ABSTRACT FROM AUTHOR]

The present paper includes the fabrication of Al7075-Mica-Kaolinite HMMC with various reinforcement ratios (i.e., Mica (0%, 3%, 5%, 7%, 9% wt%) and Kaolinite (0%, 3%, 5%, 7%, 9% wt%) respectively by using Stir casting method. The work operations performed on the fabricated specimen are Thermal conductivity testing, Microstructure Analysis, and Wear behavior. After analyzing the specimen under various tests, a conclusion was made. Theresult of the Metallurgical microscope reveals that the average grain size decreases as the reinforcement ratios increase. We observed that the wear rate and coefficient of friction increase by load and decrease by an increase in reinforcement in both dry and wet conditions. [ABSTRACT FROM AUTHOR]

This paper focused on analytic modeling of the effective thermal conductivity of bio-composite building materials. The analytic model adopted in this paper is the homogenization method. The principal idea of this method is to characterize the effective thermal conductivity from a microstructural description of the heterogeneous material and the knowledge of the local behavior of constituents (matrix and fiber) using a micromechanical approach. A three schemes (the dilute scheme, Auto-coherent scheme and the Mori-Tanaka scheme) are introduced and compared with Voigt-Reuss and Hashin-Shtrikman bounds and with experimental data at low fraction. A good agreement between the three schemes and Voigt-Reuss and Hashin-Shtrikman bounds and experimental values was revealed. The maximum deviations remain lower than 4.4% between Mori-Tanaka scheme and experimental data. [ABSTRACT FROM AUTHOR]

The energy efficiency of buildings is assessed on the base of thermal insulation properties that can help to save energy costs as well as environment. The wooden materials are widely used as they become significantly recyclable and nature-friendly. Their thermal insulation properties have to be known for construction purposes. The modern experimental methods for the Thermophysical measurements are highly desired in this field. The methodology for the experimental measurement setup has to be optimized and possible disturbing effects at measurements have to be taking into account. The first more sophisticated method is to include disturbing effect into the model or to use the second one by arrangement of the sample set geometry as close as possible to the ideal state. The pulse transient method is relatively fast in comparison with stationary methods. It is simple for experimental arrangement and reliable for large scale of materials. Measurement reliability in this paper was tested by increasing the heat pulse energy, as the estimated Thermophysical parameters have to be independent on used power. The data scattering found for all measurements was found below 2% for all Thermophysical parameters. [ABSTRACT FROM AUTHOR]

Measurement and assessment of thermo-physical properties of magnesium oxychloride cement (MOC) with graphene nanoplatelets of different specific surface, namely 300 m2/g and 750 m2/g, is presented in the paper. For the measurement, step-wise transient technique was used. In the experiments, the dependence of thermal conductivity and specific heat capacity of the hardened MOC-based composites was determined. The results of thermal conductivity and specific heat capacity were compared with the experimentally determined and tabulated values of PLA (polylactic acid). It was found that the thermal conductivity is about 1.5 times greater; on the contrary, the heat capacity is 0.8 times smaller than the corresponding parameters of PLA. It was revealed that both assessed thermal parameters depend on the specific surface of the nanoparticles and on the compaction time of the fresh composite mix. [ABSTRACT FROM AUTHOR]

From the beginning, the buildings have been tasked with protecting man from the external environmental impacts. Technological development has brought with its buildings and building structures development. Nowadays, the expectation is that in the interior of buildings it is for man to ensure a comfortable environment at all times of the year. External environmental conditions offsetting specifically requires a large amount of energy. In the European Union for buildings, its energy consumption accounts for about 20–40% of total energy consumption. The amount of energy required can be reduced, for which is a good solution. With thermal insulation, we reduce both in the building the transfer of the amount of heat generated or introduced into the building to the external environment, or it also minimizes the amount of heat that enters by radiation. Polystyrene insulations are ordinary, and their thermal properties are well known. However, the most promising type is the graphite enhanced one with relatively little information. These graphite doped material products have much better thermal insulation properties than the conventional (white) ones. In this paper, measurements of thermal conductivity after thermal annealing will be presented. Moreover, we will show some structural changes, and differential scanning calorimetry measurement results, as well. [ABSTRACT FROM AUTHOR]

This paper presents an optimization of the Al2O3/distilled water-based nanofluid process parameters for enhancing its thermal conductivity. Nanoparticle volume concentration, nanoparticle size, sonication time, stirring time, and surfactant volume concentration are selected as optimization factors to obtain higher thermal conductivity. Eighteen different nanofluid samples having various preparation parameters are determined and prepared as per the Taguchi orthogonal array. Thermal conductivity was measured using the KD2 Pro thermal properties analyzer at a working temperature of 28 °C. To study the structure and crystallite size of alumina nanoparticles, we used X-ray diffraction. A scanning electron microscope is used to investigate the morphology and size of Al2O3 nanoparticles. To assess the effect of each parameter on thermal conductivity, the main effect plot for means and the signal-to-noise ratio are utilized. The statistical contribution percentage of each parameter on thermal conductivity is determined using an analysis of variance. The signal-to-noise ratio demonstrated that the nanoparticle concentration in a base fluid is the most affecting parameter, with a delta value of 0.715. Furthermore, with delta values of 0.461, 0.413, 0.272, and 0.177, the stirring time, sonication time, surfactant concentration, and nanoparticle size all play significant roles in nanofluid thermal conductivity. The outcome of the analysis of variance shows that the nanoparticle concentration in the base fluid has the most significant impact on the thermal conductivity of the nanofluid with a contribution of 36.64%, whereas initial stirring has a contribution of 26.82% and sonication time has a contribution of 19.76%, while surfactant concentration has an 8.83% contribution and nanoparticle size has a less significant contribution with a 4.06% contribution on the thermal conductivity of the nanofluid. The obtained results indicate that the thermal conductivity of the Al2O3/distilled water-based nanofluid increased by 7.146% compared to the base fluid, i.e., distilled water. The optimum thermal conductivity is obtained as 0.640732 W/m-K at optimum parameter settings of 0.3% of nanoparticle concentration, with a nanoparticle size of 50 nm, 40 minutes of sonication time, and 10 minutes of initial stirring time with 0.2% of surfactant concentration, A confirmation test with optimized parameters was finally carried out to ensure the method's confidence. [ABSTRACT FROM AUTHOR]

In this paper, the effect of nanoclay content (1, 3 and 5 phr) in recycled high-density polyethylene (r-HDPE) on the mechanical tensile, water absorption and thermal properties was studied. The nanocomposites were prepared by a twin- screw co-rotating extruder and followed by hot/cold pressing machine. A fixed amount of 3 % polyethylene-grafted-maleic anhydride (PE-g-MA) was add to couple the polymer matrix and nanofiller in the nanocomposite. The tensile result showed that the nanocomposite reinforced with 3 phr of nanoclay exhibited the highest tensile strength (21.7 MPa) and Young's modulus (937.8 MPa). At 3 phr, the scanning electron microscope (SEM) micrograph showed the good interaction between matrix and filler phases. Based on water absorption testing, the water capacity increased with the content of hydrophilic nanoclay, however, the maximum water absorption of 1.2 % was considered as in the acceptable level in the industry field. The improved thermal stability was observed for the nanocomposites with the incorporation of low loading (1 and 3 phr) nanoclay into r-HDPE matrix where its presence delayed the melting temperature. The addition of 3 phr nanoclay and above was found to reduce the degree of crystallinity for nanocomposites. [ABSTRACT FROM AUTHOR]

The research paper provides selection of microfluidic platform, or "lab-on-a-chip" device in which blood thermal properties are validated to assess heat flow condition in laminar behavior considering pseudoplastic non-Newtonian type. Modeling of microfluidic platform is based on computational domain setup in which Poiseuille-like velocity flow for rectangular tube is simplified within quasi-boundary system. The Boussinesq-approximated Navier-Stokes presents a characterized fluid flow contained within boundary value problem that leads to the development of multi-scalar platform due to Fourier conduction. Simulation of steady-laminar model using ANSYS FLUENT offers thermal property plot analysis between heat-wall conduction, velocity, temperature, characteristic length when Grashof>10^8 and Nusselt at 1.00. Results of validating the computation grid refinement show planar chamber with least truncation error: 0.89%, 13.5% and 9.19% for 6x6, 5x5 and 7x7 domains respectively. Numerical approximations for 7x7 domains are selected despite higher residuals than 5x5 and 6x6 domains, thus solution model shows that serpentine – 7x7 has least relative error 0.133% at heat flux-Lc relationship with perfect aspect ratio 1.00. The CFD characterization suggests better simulation when modelling symmetric yet complex configuration of devices are optimally specified. [ABSTRACT FROM AUTHOR]

Measurement and assessment of thermo-physical properties of magnesium oxychloride cement (MOC) with implemented phase change material based on paraffin wax encapsulated in polymer shell, is presented in the paper. The measurement method and mathematical interpretation of thermal conductivity and specific heat capacity assessment was derived from the Thermophysical Transient Tester 1.02 that was developed at the Institute of Physics, Slovak Academy of Sciences. Within the test, thermal responses between two thermal sources were measured during the step wise heat reference source and source generating step wise heat. It was revealed that both investigated thermal parameters depend on the dosage of PCM in composite mixture, thus porosity of prepared materials and thermal characteristics of PCM itself. The obtained data point to the substantial improvement of heat storage capacity of MOC by the use of powdered PCM. [ABSTRACT FROM AUTHOR]

Gelling polymers, used for the fabrication of hydrogels, are employed for various applications in medical engineering. The present paper explores a novel approach for the additive manufacturing of polypropylene-hydrogel composites by applying laser-based powder bed fusion of powder blends at ambient temperatures, hence allowing for the integration of additives sensitive to heat degradation. Based on applying superposed fractal exposure strategies for the temporally and spatially discretized melting of prepared powder blends, the processing of composites containing a proportion of up to 75% of agarose can be demonstrated. Prepared specimens depict a water absorption exceeding 100 wt-% while exhibiting non-linear, progressive mechanical properties under compressive stress and enhanced stress relaxation similar to human cartilage tissue. The results illustrate the suitability of fractal exposure strategies for the processing of materials sensitive to heat degradation with divergent thermal properties. Furthermore, the proposed approach provides a novel process route for the fabrication of functionalized polymer components, representing a foundation for the integration of hydrogels for medical applications, such as drug delivery applications and functionalized, load-bearing scaffolds. [ABSTRACT FROM AUTHOR]

Newly developed plant-based particle board was investigated in this paper. Rapeseed straw is used as the particle, and epoxy resin as the binder. This paper investigated the effect of different surface treatment of rape straw on selected properties of particle boards. Samples were made via cold pressing with a pressure of 4 MPa. In order to analyze the effect of the surface treatment on the properties of rapeseed particle board in more detail, basic physical, moisture and thermal properties were measured. It was found that the properties of particle boards are slightly dependent on the surface treatment. The impact of the surface treatment on basic physical properties, water vapor diffusion properties and thermal properties is relatively low. The surface treatment of straw has the greatest effect on the sorption isotherms and thickness swelling. From this point of view, the sodium hydroxide treatment is the least suitable. [ABSTRACT FROM AUTHOR]

The paper presents the finite element modeling of the spatial heat transfer to identify the temperature and the heat flux distributions both in the linear and point thermal bridges in various up-to-date wall systems. The paper considers the spatial heat transfer in the corner zone of the brickwork fragment. The ANSYS finite element program is used for the numerical simulation of the temperature fields and thermal fluxes for the brickwork connection with a hollow-core slab and a balcony slab. The influence of hollow cores in the floor slab is considered in relation to the temperature behavior along the inner surface of the brickwork fragment. To eliminate the negative effect from thermal bridging, it is suggested to increase the temperature on this inner surface. The brickwork thermal properties are investigated herein. [ABSTRACT FROM AUTHOR]

The paper presents the results of tests of thermal properties of heavy-weight concrete designed to be used in the manufacturing of small prefabricated masonry elements that can be used in the construction of demountable shielding structures. The specificity of the tested concrete is the use of waste copper slag as fine aggregate instead of sand. The results obtained in the case of two concrete variants (one with basalt magnetite aggregate and the other with barite aggregate) were compared with reference concrete made also in two variants (differing in the type of fine aggregate). The obtained results showed that the use of waste copper slag in shielding concrete significantly reduces the values of its thermal conductivity and specific heat and to a lesser extent also its thermal diffusivity and thermal volume capacity. [ABSTRACT FROM AUTHOR]

This paper analyses the performance of advanced mathematical model aimed for description of heat and moisture transport in porous materials including phase change of transported moisture. The objective of the research is to investigate the effect of two types of thermal input parameters. First, the model is performed with the standard thermal properties determined for the room temperatures. Then, the same simulation is performed with the properties determined in the range of subzero to room temperature. The results are compared against each other and the thermal and energy performance of studied element is analyzed. The results showed there is a difference about 5 °C in temperature distribution and about 6 % in energy performance. [ABSTRACT FROM AUTHOR]

Geopolymers can be considered as competitive construction materials to cement-based materials. It is mainly due to their high strength, good chemical resistance, thermal stability and favorable development of hydration heat at early age. A reasonable amount of electrically conductive admixtures close to the percolation threshold enhances electrical properties of geopolymers which leads to their potential utilization in self-heating applications. In general, electrical and thermal conductivity is essential for an effective heat evolution and distribution through the material. Sufficiently high electrical conductivity ensures evolution of Joule’s heat initiated by acting of a power supply, whereas sufficiently high thermal conductivity ensures effective spreading of the generated heat. To assess the self-heating ability of such materials and effectiveness of their self-heating, it is necessary to experimentally determine electrical and thermal properties. In this paper, basic physical, electrical and thermal properties of geopolymers with different dosages of electrically conductive carbon black admixture are measured. Basic physical properties are determined by the gravimetric method, DC electrical properties by the 4-probes method and thermal properties by the pulse method. Addition of 10 wt.% of CB to the reference geopolymer is found to lead to a significant increase of electrical conductivity at the cost of a decrease of thermal conductivity. Nevertheless, geopolymer enhanced in such a way can be considered as a promising self-heating material. [ABSTRACT FROM AUTHOR]

Measurement and assessment of thermo-physical properties of Ultra High Performance Fiber Reinforced Concrete (UHPFRC) are presented in the paper. The examined fine-grained concrete samples were reinforced with hybrid reinforcement based on combination of steel and PVA fibers. For the measurement, newly designed step-wise transient method was used. In the experiments, retained thermal conductivity and specific heat capacity of UHPFRC samples after their high-temperature exposure to the temperatures starting from laboratory temperature up to 1200 °C were studied. The obtained results gave evidence of the structural changes that examined concretes underwent at heightemperatures. The data on thermal conductivity and specific heat capacity represents valuable information for building practice, materials researchers and building designers. It can be used e.g., as input data for computational modeling of heat transport and storage in UHPFRC-based construction elements exposed to high temperatures. [ABSTRACT FROM AUTHOR]

Composites is a type of material which is made offibers or fillers embedded in matrix. Fibers and fillers are used as reinforcing materials to get the desirable properties to the composite laminates. The matrix is used for binding the reinforcing materials in place and to distribute the stresses due to external force uniformly among the constituent reinforcement materials. In this paper, we are studying an effect of copper Nano particles on mechanical, thermal and morphological properties of short jute fiber reinforced poly lactic acid composites. The composition with 80 grams PLA and 20 grams fiber has the highest tensile strength of 56 N/mm2 as well as has the highest yield strength of 45 N/mm2. It is evident that addition of copper Nano powder decreases both tensile and yield strength. The composition with 77 grams PLA, 20 grams fiber and 3 grams copper Nano powder has the highest Izod impact strength of 16 joules and the Charpy impact strength of 28 joules and addition of copper Nano powder increases both Izod and charpy impact strength. The composition with 77 grams PLA, 20 grams fiber and 3 grams copper Nano powder shows the highest value of Brinell Hardness Strength i.e. 102.79 BHN and addition of copper Nano powder increases the hardness strength. Addition of up to 2 % of copper Nano Powder decreases the temperature both at 10 and 50 % weight loss. Further addition of copper Nano powder does not show any significant changes in the temperature both at 10 and 50 % weight loss. It is clearly indicate in the SEM image that there was no accumulation of Copper Nano powder in the matrix and copper Nano powder is covered the rough surface of the Jute fibres and remain intact even in the application of force. [ABSTRACT FROM AUTHOR]

Improvement of intellectual abilities and practical skills of graduate students in the field of preparation and operation of experiment for accurate determination of hygrothermal properties of porous materials is exemplified via measurements using a specifically designed apparatus from which water and heat transport parameters can be obtained. This supports students in the development of physical thinking, competences in processing of experimental data, and broadening scientific and research potential and intellectual skills in general. A specific task for students described in this paper is the measurement of a time evolution of a temperature of cylindrical samples immersed in water, while the ambient and water temperatures were kept constant. This task can be easily performed by graduate (and even undergraduate) students, so that they can actually become part of research activities in the whole process of the determination of hygrothermal properties using this laboratory experiment. The subsequent task-an inverse analysis of the measured time evolution-is scientifically more advanced and could be performed by some PhD students (perhaps under supervision of a senior researcher, or when an appropriate software tool for the inverse analysis is developed). This latter task is not analyzed in this paper, however. Nevertheless, students can analyze measuring data even during distance education. [ABSTRACT FROM AUTHOR]

Particles, specifically sands, may be an alternative pathway for Thermal Energy Storage (TES) in high-temperature Concentrated Solar Power (CSP) in place of using solar salts. As seen in testing for this research, these particles have greater thermal stability at higher temperatures than solar salts while still being relatively inexpensive. This work explores the high-temperature static thermal properties, such as bulk conductivity and heat capacity, of various particles. Future work will use these properties to study the dynamic characteristics of sand including the heat transfer coefficients for high-temperature, packed-bed particle flow. To this end, this paper also describes an experimental facility that is being fabricated in order to accomplish these flowing particles tests. [ABSTRACT FROM AUTHOR]

The measurement of thermal properties, such as thermal conductivity, thermal resistivity, heat capacity, and thermal diffusivity for materials, is essential for many civil and electrical engineering projects as well as numerous field applications, including heating the soil beneath a building, producing electricity, removing waste from thermal and nuclear power plants, and burying cables. Different geotechnical factors, such as the type of soil, water content, grain size distribution, density, and compaction factors, all affect the thermal conductivity of soil. Literature studies has been done related to work and presented in this paper. In previous research, heat source methods were used to test the thermal conductivity of soil. Consequently, doing laboratory and field measurements is expensive and time-consuming. In this work, a constructed probe is used to measure thermal conductivity. Glycerin was used to calibrate the manufactured probe. Water has a greater thermal conductivity than soil minerals, and particle to particle interface increases as density improves. As a result of these fundamental influences, thermal conductivity of the soil improves as water content and density improves. Therefore, obtained thermal conductivity values were represented and explained with graphs for considered materials. [ABSTRACT FROM AUTHOR]

The paper deals with the investigation of plastic deformation localization in mechanical tension tests of low carbon samples in the initial state and after 25 years of operation in thermal and power equipment. It was established in the tests long before the global loss of stability that stable localized deformation zones are formed in the area of further fracture. In the material after operation, these zones are seen earlier than in the initial steel. A parameter defining the degree of homogeneous material without localized deformations is proposed; this parameter can be used to predict the condition of long-term operated thermal and power equipment. [ABSTRACT FROM AUTHOR]

Most of waste tires are landfill disposed, which is the most common method. This method will be drastically reduced in the near future due to the recent introduction of European Union directives that include significant restrictions on this practice in favor of alternatives oriented towards material and energy recovery. One of the possible solutions for the use of scrap tire rubber is to incorporate it into concrete, to replace some of the natural aggregate. This paper is aimed at the thermal performance of a lightweight concrete incorporating high volume of crushed waste tires as partial substitution of natural silica aggregate of the same grain size. In order to quantify the effect of waste tires-base aggregate on concrete properties, a reference concrete mix without waste rubber was studied as well. For the applied crushed waste tire rubber, bulk density, matrix density, and particle size distribution were measured. Specific attention was paid to thermal transport and storage properties of waste rubber that were examined in dependence on compaction time. For the developed lightweight concrete, thermal properties were accessed using transient impulse technique, whereas the measurement was done in dependence on moisture content, at the dry state and at the fully water saturated state. Additionally, the investigated thermal properties were plotted as function of porosity and density. Mechanical resistance was also tested. The tested lightweight concrete was found to be an alternative construction material possessing improved thermal insulation function and sufficient mechanical resistance. Furthermore, the environmental advantages caused by reusing used tires and consequently eliminating their disposal should also be taken into consideration. [ABSTRACT FROM AUTHOR]

This paper presents the current state of the art of methods for calculating the physical processes of heat transfer occurring during the coolant boiling in pipes of spacecraft thermal control systems. The priority tasks of rocket and space technology are modernization and technical improvement, and in general, a tendency towards an increase in the linear dimensions and power-to-weight ratio of the spacecraft is determined. However, in this case, it becomes necessary to remove a large amount of heat from more powerful equipment located on the spacecraft. For this, it is advisable to use two-phase thermal control systems. Such systems have greater productivity and efficiency, which determines the prospects for their use in planned space projects. For two-phase thermal control systems, there are a number of problems associated with the lack of reliable experimental and theoretical data on the processes of boiling and condensation in boundary conditions. The specificity of two different boiling modes, convective and nucleate, is analyzed. The described calculation methods are compared. [ABSTRACT FROM AUTHOR]

The global production of fired ceramic bricks represents a large environmental burden in form of energy consumption and greenhouse gasses emission. The production process has therefore become an object of interests of several studies aiming at its optimization to reduce the negative environmental impacts. Within these optimizations, the precise knowledge of thermal properties of clays undergoing the firing process is one of the key information that conditions the successful solution of the problem. This paper therefore aims at determination of temperature-dependent thermal conductivity of clays. Using a set of thermocouples, the temperature distribution in the sample is monitored, being exposed to one-sided heating. The temperature field deformation due to presence of metal wires is then overcame using computational modelling that is able to distinguish the particular contributions of clay/thermocouples to the ongoing heat transfer. Based on this assumption, such a thermal conductivity of clay is then sought, that provides the same temperature distribution as the experiment. The thermal conductivity values of clays were found to range between 0.58 W·m−1·K−1 and 1.97 W·m−1·K−1, depending on the temperature. [ABSTRACT FROM AUTHOR]

The experimental analysis of several types of fine-grained high performance concretes is presented in this paper. Besides mechanical parameters, presented analysis aims also at determination of basic physical and heat and moisture transport and storage parameters. Within the frame of this paper, three different mixtures of fine-grained high performance concrete were designed, distinguished by the type of binder (unitary-, binary- or ternary-based) and their properties were compared with two types common concretes. Experimental results show that the compressive and bending strength, static modulus of elasticity of high performance concretes are significantly better than for other two concrete mixtures, regardless of the type of binder. Thermal conductivity of high performance concretes was higher in dry state, but due to lower open porosity and lower values of moisture diffusivity these concretes are more resistance to liquid moisture intake, therefore they evince better thermal properties in fully saturated state. Since the ternary-based high performance concrete contains also secondary raw materials as partial cement replacement and its properties were mostly better than other investigated concretes, it can be considered as an environmental friendly solution. [ABSTRACT FROM AUTHOR]

In this paper, the improvement of vacuum solar collector efficiency is studied by two methods. The first method is to place a solar reflective curtain in front of the solar vacuum collector that operates on the solar panel system. This curtain increases the amount of reflection of solar radiation back to the vacuum collector. The curtain automatically follows the sun's rays, and the reflectors' movement depends on the nanofluid's temperature. The second method uses the ZrO2 nanofluid with a diameter of 60 nm with distilled water. The experiment used three volume concentrations, 1,3 and 5% by volume, with three flow rates of 30,50, and 60 L/m, respectively. The results showed an improvement of the thermal properties of the solar vacuum collector when using the solar reflective curtain and nano-liquid by 10.76%, while the amount of progress without using the solar reflective curtain was 5. 51%. [ABSTRACT FROM AUTHOR]

We have investigated the various lattice distortions and their effect on thermal properties of Pr1-xBaxCoO3 cobaltates. The formulation to calculate the temperature-dependent (1K1-xBaxCoO3 (0.1≤x≤0.5) using modified Rigid Ion Model (RIM) are also presented. In addition, the results on the cohesive energy (ϕ) in orthorhombic perovskite phase, bulk modulus (B) and Debye temperature (θD) are calculated using RIM and Atoms in Molecules (AIM) theory. [ABSTRACT FROM AUTHOR]

This paper presents an experimental study on the thermal and mechanical properties of jute polyester composites. Jute polyester composites were fabricated with different thickness by reinforcing jute-cotton blended fabrics. The thermal conductivity, thermogravimetric analysis and water absorption test were conducted to evaluate their performance. MEKPO (methyl ethyl ketone per oxide) wt. %, nano-cellulose wt % and polyester resin (%) were optimized for the performance of jute polyester composites to be suitable for rural poultry housing. The best weight proportion of MEKPO (methyl ethyl ketone peroxide), nano-cellulose and composite thickness were found 1.5 wt.%, 6 wt.% and 3 mm respectively. It was revealed that composite fabricated with 60/40 jute/cotton blended fabrics exhibited the best performance in composite fabrication having thickness of 3 mm. [ABSTRACT FROM AUTHOR]

Experimental data of thermal stability of the microstructure and mechanical properties (exemplified by the microhardness tests) of the ultrafine grained (UFG) Ti–45 wt % Nb alloy after long-term thermal influence were presented in the paper. UFG structure in the alloy was formed with the severe plastic deformation (SPD) method. It was proved that the SPD method including the multiple abc-pressing and multi-pass rolling and further pre-recrystallizing annealing enhances the formation of UFG structures with the mean element size of 0.25 µm. Samples of Ti–45 wt % Nb alloy in UFG state were annealed at 350 and 400°C during 1, 5, 10, 24, 120, 240 and 360 hours. It was shown that the UFG structure was stable after annealing at 350 and 400°C as a result of thermal influence within the time range up to 360 hours. Stability of mechanical properties depended on the temperature and duration of annealing, i.e. microhardness of 3200 MPa was remained during 120 hours of annealing at 350°C, while microhardness of 3000 MPa was remained during 10 hours of annealing at 400°C. [ABSTRACT FROM AUTHOR]

The paper aimed to investigate the thermal properties of Limestone rock by the Pulse Transient Technique. using Slab model. This technique helps to measure the thermal conductivity, thermal diffusivity, specific heat capacity and additionally heat capacity of the heat source and the heat transfer coefficient between the plane heat source and sample surface in a single measurement. The experiment is done with dry contact condition in-between plane heat source, thermal sensor, and specimen interfaces. The results obtained from the slab model seem to agree better to the previously reported cuboid model usually used for measurements performed with contact thermal agent. In this paper, we have discussed the Uncertainty analysis of the estimation of the parameters by slab model, done for real measurements conducted for Limestone a rock sample that is derived from sensitivity coefficients theory. The thermophysical parameter of the rock motivates to understand the temperature distribution over time and depth, which also describes its thermal history. Hence the research on rock's thermal property can be widely used in the geothermal heat flow and storage systems. [ABSTRACT FROM AUTHOR]

Latent heat storage technology in CSP plant has been studied to enhance the dispatchability of solar energy in order to meet fluctuating electricity needs. A novel concept using metal alloys as latent heat storage material gives way to achieve this technology. In this paper, we analyzed the structural and thermal properties of Cu-Ge alloy to evaluate the potential of metallic PCM for high temperature TES application. Containment options for metallic PCM were explored and the materials are selected for long term operation. Compatibility tests of stainless steel, alumina and SiC ceramics under inert atmosphere were performed at high temperatures (800°C) for a duration of 1 month (720 h) in order to develop a suitable container material for thermal energy storage system. [ABSTRACT FROM AUTHOR]

The paper deals with the application of crumb rubber made by re-processing of disposed automobile tires in production of concrete containing fine aggregate in the size up to 4 mm only. In concrete composition, nature silica sand was replaced by crumb rubber in the dosage of 10-30 % by mass. The water binder ratio of 0.5 was maintained similar for all studied concretes. For the examined materials, basic physical properties and in particular thermo-physical properties at elevated temperatures were investigated after 28 days of samples water curing. Obtained experimental results indicated that thermal conductivity as well volumetric heat capacity were strongly effected by temperature due to the release of aromatic oils and liquid additives coming from temperature loaded crumb rubber, porosity changes and water loss. [ABSTRACT FROM AUTHOR]

Different experimental studies showed that the inclusion of nanoparticles into pure refrigerant leads to improved thermal properties and thereby better performance and energy savings of refrigerators compared to conventional refrigerant systems. This paper intends to explore the thermophysical, rheological and convective heat transfer properties of Al2O3/R600a (alumina/isobutane) nanorefrigerant at several temperatures and volume fractions (1 to 5 %) of Al2O3 nanoparticles. Additionally, convective heat transfer coefficient is also studied by varying the mass flux of the nanorefrigerant flowing through a smooth tube. Obtained results show that thermal conductivity, density, viscosity and convective heat transfer coefficient of the nanorefrigerant increase while specific heat and Nusselt number decrease with the increase in volume fraction of nanoparticles at any fixed temperature. Moreover, thermal conductivity, specific heat, Nusselt number and convective heat transfer coefficient exhibit a rising trend, whereas density and viscosity show the opposite trend with the increase in temperature. [ABSTRACT FROM AUTHOR]

In this paper investigated the effect of cetyltrimethylammoniumbromide (CTAB) surfactant of heat pipe thermal performance usingTiO2-water nanofluid as the working fluid. TiO2 nanofluids was prepared using titanium dioxide nanoparticles (TiO2 NPs) and modified with CTAB as cationic surfactant. The particles size of TiO2 NPs used in these experiment were 21 nm and density of 130 g/L. The base working fluid was demineralized water. The TiO2-water nanofluid was prepared using a one step method by mixing method under ultrasonication for 10 minutes, TiO2 NPs concentration of 8% volumetric loading, demineralized water of 100 mL, pH was adjusted at 8, and CTAB of 0.029 w.%. Thermal resistances of the heat pipe containing the TiO2 − CTAB surfactant (2.8 W°C-1) was lower than those found in TiO2 NPs (3.12 W°C-1) and pure deminerilized water as the working fluid (5.71 W°C-1). The TiO2 nanoparticles and cationic surfactant has an important role to reduce the thermal resistance in the heat pipe (2.9 W°C-1). The TiO2 system and TiO2-surfactant nanofluid can be decreased the temperature in the wall of heat pipe until 32 and 36%, respectively. The TiO2 NPs and CTAB cationic surfactant has an important role to reduce the thermal resistance in the heat pipe. This field of research has a great potential for improvement the thermal conductivity of TiO2 nanofluid that can be applied as heat transfer in the heat pipe. The addition of cationic surfactant into the nanofluid can be used to minimize nanoparticles aggregation and improve the dispersion behavior of nanofluid. [ABSTRACT FROM AUTHOR]

The current paper is concentrated on the MHD hybrid nanofluid-flow with heat-transfer on a moving/changing plate through porous media and thermal radiation. The great mixture Cu with Al2O3 nanoparticles along with H2O as the important base fluid is utilized for the analysis. Mathematical transformation decreases the convolution of important PDEs to a scheme of ODEs. This will be numerically solved with the help of function-bvp4c by making use of Software tool/MATLAB for multiple values with various significant parameters. This analysis is significant in identifying the crucial property thermal-behaviour of mixture Cu-Al2O3/H2O when the imperative physical parameters including magnetic_field(M), Heat_generation_parameter (β), velocity_slip_parameter(A), Thermal_radiation_parameter (R), Thermal_Slip_parameter(B), Porosity_parameter(P) and suction_parameter(S) are excellently entrenched. The findings are modern and unique with numerous practical uses in the contemporary industry. [ABSTRACT FROM AUTHOR]

Development of advanced materials resistant to high temperature, needed namely for the design of heat storage for low-energy and passive buildings, requires simple, inexpensive and reliable methods of identification of their temperature- sensitive thermal conductivity and diffusivity, covering both well-advised experimental setting and implementation of robust and effective computational algorithms. Special geometrical configurations offer a possibility of quasianalytical evaluation of temperature development for direct problems, whereas inverse problems of simultaneous evaluation of thermal conductivity and diffusivity must be handled carefully, using some least-squares (minimum variance) arguments. This paper demonstrates the proper mathematical and computational approach to such model problem, thanks to the radial symmetry of hot-wire measurements, including its numerical implementation. [ABSTRACT FROM AUTHOR]

The effect of water ice-phase change on thermal performance of integrated building material is investigated in this paper. As a characteristic construction, simple external wall made of aerated autoclaved concrete was assumed which was exposed to dynamic climatic condition of Šerák, Czech Republic. The computational modelling of hygrothermal performance was carried out using computer codes HEMOT and SIFEL that work on the basis of finite element method. The effect of phase change was taken into account by fixed-domain method, when experimentally determined effective specific heat capacity was used as a material parameter. It comprises also the effect of heat consumption and heat release that accompany the water-ice phase change. Comparing to the results with specific heat capacity, the effect of phase change on thermal performance could be quantified. The results showed that temperature fields can differ more than 6 °C. Additionally, the amount energy transported through the wall may be higher up to 4 %. This confirmed, that the effect water-ice phase change should be included in all the relevant energy calculations. [ABSTRACT FROM AUTHOR]

In this paper a simple damage function for the relative assessment of the material degradation is presented. The damage function is based on the analysis of temperature and moisture content fields in the investigated material together with its pore size distribution function. In this way the relative assessment of frost induced damage can be provided. The application of the damage function is demonstrated on several wall assemblies exposed to several environmental loads in the Czech Republic and the comparison of weather year severity to the studied constructions is presented. [ABSTRACT FROM AUTHOR]

The Hot-ball method is an innovative transient method for measuring thermophysical properties. The principle is based on heating of a small ball, incorporated in measured medium, by constant heating power and simultaneous measuring of the ball's temperature response since the heating was initiated. The shape of the temperature response depends on thermophysical properties of the medium, where the sensor is placed. This method is patented by Institute of Physics, SAS, where the method and sensors based on this method are being developed. At the beginning of the development of sensors for this method we were oriented on monitoring applications, where relative precision is much more important than accuracy. Meanwhile, the quality of sensors was improved good enough to be used for a new application - absolute measuring of thermophysical parameters of low thermally conductive materials. This paper describes experimental verification and validation of measurement by hot-ball method. Thanks to cooperation with Laboratory of Soft Matter and Biophysics of Catholic University of Leuven in Belgium, established Guarded Hot Plate method was used as a reference. Details about measuring setups, description of the experiments and results of the comparison are presented. [ABSTRACT FROM AUTHOR]

A good sensor must be highly sensitive, faster in response, of low cost cum easily producible, and highly reliable. Incorporation of nano-dimensional particles/ wires makes conventional sensors more effective in terms of fulfilling the above requirements. For example, Carbon Nanotubes (CNTs) are promising sensing element because of its large aspect ratio, unique electronic and thermal properties. In addition to their use for widely reported chemical sensing, it has also been explored for temperature sensing. This paper presents the fabrication of CNTs based temperature sensor, prepared on silicon substrate using low cost spray coating method, which is reliable and reproducible method to prepare uniform CNTs thin films on any substrate. Besides this, simple and inexpensive method of preparation of dispersion of single walled CNTs (SWNTs) in 1,2 dichlorobenzene by using probe type ultrasonicator for debundling the CNTs for improving sensor response were used. The electrical contacts over the dispersed SWNTs were taken using silver paste electrodes. Fabricated sensors clearly show immediate change in resistance as a response to change in temperature of SWNTs. The measured sensitivity (change in resistance with temperature) of the sensor was found ~ 0.29%/0C in the 25°C to 60°C temperature range. [ABSTRACT FROM AUTHOR]

This paper investigates the effects of using the S2S and the DO method in the CFD simulation of a cavity to identify a convenient model for simulating radiative heat transfer. A 3D model for an office room fitted with a sizeable controllable glass window was developed to carry out a transient analysis of a room's thermal performance when the glass is at its opaque state while accounting for each of the models. A transient user-defined function (UDF) boundary condition, based on radiative heat flux, was set as an incident solar load boundary condition on the dynamic glazing to study the dispersed temperature and the airflow in the room. Various configurations of the enclosed room with initial wall boundary condition and airflow in the room were considered under the effects of different parameters such as thermal properties, Rayleigh (Ra) and Grashof (Gr) numbers, surface emissivity, and absorption. Radiative CFD results were compared, and the importance of accounting for radiation was noted. The S2S displayed good performance, whereas unexpected temperature distribution was observed with the DO method. Although heat transfer depends on the transmitting material's thermal properties, further analysis has shown that the S2S, along with the SST k-ꞷ viscous turbulence model, using piecewise linear approximation, is a reliable CFD model setting for performing a thermal analysis of a highly glazed enclosed room. The results were also compared to a previous 2D analysis of an enclosed space without accounting for radiation. Results had shown that the interior temperature was less than 2% for the S2S when radiation was overlooked. Further study would involve the validation of the computed room temperature with experimental data which will show the efficiency of the two radiation model methods in performing the thermal performance of a building. [ABSTRACT FROM AUTHOR]