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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]

We worked on the energy contained in the molecules arranged in genetic molecular sequence. The binding energy of the genetic alphabet, i.e., A, C, G, T have been taken from experimental data and they are used in the calculation of the entropy along the sequence. This is termed as topological entropy on the molecular sequence. The topological entropy of various species is used for principal component analysis, which is a tool to reduce the multidimensional data to less dimension for data visualization. Further the output of the analysis is used for the determination of dissimilarity between the sequences. The technique is verified using HEV molecular sequences. [ABSTRACT FROM AUTHOR]

This paper presents low cost fabrication method of MAPbBr3 crystalline structures directly on the polylactic acid (PLA) carbon-coated substrates. Fabrication was carried out using three different crystallization processes: inverse temperature crystallization (ITC), anti-solvent vapor-assisted crystallization (AVC) and combination of both methods. This paper also includes the study of crystallization kinetics for both the perovskite and its precursors. Moreover, temperature modulated space-charge-limited current method (TM-SCLC) was applied to the measured current-voltage characteristics to estimate the concentration of free and trapped charge carriers, the microscopic mobility of free charge carriers, the thermodynamic position of the Fermi level as well as the position of localized states and their concentration. Based on the acquired data we determined following microscopic carrier mobilities and thermodynamic Fermi level positions: μ+/μ− ≈ 0.2/4.0 cm2/V/s, ΔEF ≈ –0.48 eV for PbBr2, μ+/μ− ≈ 10/10 cm2/V/s, ΔEF ≈ –0.575 eV for MABr, and μ+/μ− ≈ 10/300 cm2/V/s, ΔEF ≈ –0.57 eV for MAPbBr3). By comparing our model with literature data (bandgap width, permittivity, effective mass of carriers, etc.) we found and characterized the monoenergetic (bi-exponential) localized states near Fermi level of the studied materials (deep traps for PbBr2, shallow traps for MAPbBr3, and states at the Fermi level for MABr). [ABSTRACT FROM AUTHOR]

The paper deals with the evaluation of the experimental data acquired by the method of temperature modulated space charge limited currents (TMSCLC) on MAPbBr3 perovskite in the dark and under irradiation. It was possible to determine the concentration of free and trapped charge carriers, microscopic mobility of free charge carriers, thermodynamic position of the Fermi level, the position of localized states and relaxation times of individual processes from the measured current-voltage characteristics and activation energy of the current. Using the literature data of the valence and conduction band, the energy distribution of the density of states in the band gap was estimated. The experimental and theoretical data were in good agreement. The shift of the Fermi level under irradiation was determined and the distribution and concentration of localized states in energy estimated. [ABSTRACT FROM AUTHOR]

For the design and prediction of thermal behaviour of energy piles the reliable computational evaluation of time-dependent temperature distribution is required. Some knowledge of analytical solutions, leading to some numerically feasible integration schemes, is welcome. This paper demonstrates such approach on certain model problems with finite cylinder heat sources, generalizing existing results, working with various infinite heat sources, or with finite line ones. [ABSTRACT FROM AUTHOR]

Drop impact on a heated substrate is one of the most important objects occurring in the main two types of cooling applications such as quenching of metals and the cooling of lasers and electronic devices. The paper reports a study of the interaction of the water drop of 10 µl impacting on a heated sapphire plate with a temperature varied within a range of 23-80°C. Dynamic viscosity at this temperature range is decreased from 1004 to 355.1×10−6 Pa·s. The influence of the temperature on liquid viscosity may lead to a substantial difference in drop dynamics. The main changing parameters are the liquid column at splashing and secondary droplets atomization. A considerable decrease of the liquid column contact diameter and an increase of the liquid column height at the splashing stage are shown with the decreasing viscosity. Secondary droplets atomization from the liquid column with increasing temperature is revealed. [ABSTRACT FROM AUTHOR]

Cerium dioxide nanoparticles are widely used in different branches, especially for its strong catalytic properties. Ceria nanoparticles used in this work were prepared via a simple and fast precipitation reaction of cerium (IV) sulfate and ammonia. Such prepared nanoparticles showed a relatively uniform crystallite size of about 2 nm. This contribution deals with immobilization techniques of ceria nanoparticles, using TEOS as SiO2 precursor, leading to the formation of CeO2/SiO2 composites. Prepared composites were characterized using primarily SEM and EDS. Additionally, the catalytic activity of such prepared composites was tested on a 2,4,6-TCP aqueous solution and crystallite sizes of ceria nanoparticles were evaluated using the Scherrer equation after the XRD measurements. [ABSTRACT FROM AUTHOR]

Magnesium oxychloride cement (MOC), more precisely Phase 5 (MOC 5-1-8), was exposed to elevated temperatures in order to explore its thermal expansion using high temperature dilatometry. MOC is fire resistant, non-hydraulic material with high strength and enormous connectivity. Because of its lower environmental impact contrary to Portland cement production, it is becoming more popular nowadays. In this paper, sample of MOC 5-1-8 was heated in the air atmosphere from a laboratory temperature to a temperature of sample cracking which is above 800 °C. From the measured data, coefficient of thermal expansion related to a specific temperature range was calculated. The obtained results pointed to the visible effect of high temperatures on material behaviour and they corresponded with chemical reactions and material structural changes initiated by action of thermal load. [ABSTRACT FROM AUTHOR]

The focal point of this article is the development trend in the material and geometric arrangement of ceramic masonry blocks made of fired clay with the thickness of 500 mm using a tongue-and-groove connections and thin-layer gluing with a horizontal joint mortar. Numerical simulation according to the Fourier equation of heat propagation is used. The concept of arranging ceramic fittings uses large internal cavities with air filling, foam silicate filling, light filling based on waste thermal insulation with silicate binder, mineral wool, polyurethane or aerogel insulation. The optimization approach seeks for the best geometric and material properties, maximizing the highest value of thermal resistance of the masonry created from the assessed blocks. The material properties are based on laboratory measurements of thermal conductivity of components used in ceramic fittings, which affect the resulting thermal resistance. [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]

The paper presents the results of research concerning two fiber materials - hemp fiber and mineral wool as a loose-fill thermal insulation materials. The analysis involved the evaluation of thermal conductivity and air permeability in the relation of bulk density. Both materials used as thermal insulation are characterized with open porosity, so convection plays a significant role in the process of heat transfer. The results of the own investigation were used to carry out the numerical simulation of heat transfer in the timber frame walls filled with those two kind of materials. The study proved that heat transfer in these insulations strongly depends on the bulk density. [ABSTRACT FROM AUTHOR]

The paper presents the results of thermal transport properties study of CsPbBr3 perovskite at room temperature. The samples were fabricated with the use of Bridgman method. For experimental investigations, the photoacoustic method in gas-microphone configuration was used. The evaluated thermal conductivity was found to be equal 1±0.3 W/(m K). Additionally, thermal conductivity was simulated with the use of equilibrium molecular dynamics approach. The value calculated with the simulation approach was found to be equal to 0.75±0.8 W/(m K). Thus, one can state good agreements of the results of simulations and experimental ones. [ABSTRACT FROM AUTHOR]

The paper evaluates the effectiveness of surface hydrophobization of high performance concrete (HPC) containing boiler slag (BS) and coal combustion dust (CCD). The following tests were performed: density, porosity, absorptivity, capability to diffuse water vapor, compressive strength, flexural strength, frost resistance, contact angle. The Wu method was used for the determination of surface free energy (SFE). The conducted studies showed that surface hydrophobization reduced the water absorption by weight and the capability to diffuse water vapor. Fourteen days after the test, a 69.9% drop in the absorptivity of the concrete containing 10% of BS was observed, in addition to 67% reduction in water vapor diffusion. Hydrophobization decreased the SFE in concrete with 5% boiler slag addition by a factor of 4, increased the contact angle as well as contributed to a 12-fold drop in mass loss following a frost resistance test, in the concretes with 10% BS addition. [ABSTRACT FROM AUTHOR]

In photoacoustic spectroscopic (PAS) technique, acoustic piston model is considered and the optical properties of solids are studied. One has to detect the photoacoustic (PA) signal produced when a sample placed in a cell is irradiated by an intensity modulated beam of light. The PA signal is used to investigate the optical properties of solids. In this paper we report on the theoretical, experimental issues on the application of photoacoustic spectroscopy for the investigation of optical properties of Cu2GeSe3 compound. Optical-absorption spectra has been obtained in the range of 0.76 -0.81 eV photon-energy at temperatures between 70 and 300 K. The thermal variation of band-gap energy has been estimated from the optical-absorption spectra at different temperatures. [ABSTRACT FROM AUTHOR]

This paper deals with the properties of commonly used exterior plasters on thermal properties of construction. The surface spectral emissivity properties of acrylate, silicate, and silicon plasters and also the dependence on abrasiveness and the color were compared. [ABSTRACT FROM AUTHOR]

This task deals with the properties and possibility of recycling the thermal insulation materials such as polystyrene and mineral wool, not only from the demolition but also the materials left over after the construction of the new buildings. These materials are tested as the filling for lightweight concrete to fill in the cavities of ceramic fitting. [ABSTRACT FROM AUTHOR]