Papers by Keyword: Specific Heat Capacity

Abstract: This research investigates the thermal performance of earth bricks made with different percentages of wastewater sludge additive (0%, 1%, 3%, 7%, 15%, 20%) in terms of cooling and heating loads, time lag and decrement factor. The simulation of a reference house (2.5m,10m,6m) using TRNSYS software allows for the evaluation of these parameters, external wall thicknesses, bulk density, thermal conductivity, and specific heat capacity are employed as inputs in dynamic thermal inertia model. The results showed that the use of bricks with higher sludge additive percentages resulted in a drop in cooling and heating loads, the lowest cooling and heating loads of 1720 KWH and 1534 KWH respectively were recorded with the highest percentage of wastewater sludge additive of 20% and the biggest wall thickness of 30cm, it was also noted that the use of higher wastewater sludge additive percentages and bigger wall thicknesses led to higher time lags and lower decrement factor, the highest time lag of 15 hours and the lowest decrement factor of 0.019 were as well recorded with the highest wastewater sludge additive of 20%, and the biggest wall thickness of 30cm. These results were attributed to the higher specific heat capacity, and lower thermal conductivity of the bricks with higher wastewater sludge additive percentages.

Abstract: This research aimed to improve the thermo-physical properties of plam oil with NaA zeolite. Palm oil was selected for heating oil due to its high flash point and environmental friendliness compared to synthetic or mineral oil. The effect of NaA zeolite concentration suspended in palm oil was investigated in terms of the specific heat capacity (Cp), viscosity (μ), viscosity index (VI), thermal analysis (TGA) and density (ρ) of palm oil. The NaA zeolite was synthesized by crystallization technique, and X-ray diffraction analysis was performed to determine NaA zeolite crystallinity. The size of NaA zeolite was measured using a particle size analyzer. The average size of the synthesized NaA zeolite was 4767 nm. After grinding process for 180 min, the average size of zeolite decreased to 632 nm. An average 632 nm NaA zeolite particle size was added to palm oil at 0.25, 0.5, 0.75 and 1 wt%. The results showed that when the NaA zeolite concentration increased, the nanofluid’s viscosity at 40 °C and 100 °C was increased. The addition of 1 wt% NaA zeolite resulted in the nanofluid having a maximum viscosity of 41.31 and 8.47 cSt at 40 °C and 100 °C, respectively. The highest viscosity index was 195 cSt when added with 0.5 wt% NaA zeolite. The density of palm oil slightly increased with increasing NaA zeolite concentrations. The specific heat capacity of palm oil increased when NaA zeolite was added. The results showed that NaA zeolite allowed palm oil to store heat energy better than palm oil, enabling it to release and absorb more heat during heat transfer. Thermogravimetric analysis, palm oil initiated to degrade at 263 °C, while the addition NaA zeolite in palm oil indicated that palm oil initiated to degrade at 350 °C. The shift in the degradation curve demonstrated that the nanofluid could withstand high temperatures. Adding NaA zeolite to palm oil showed that palm oil could endure more heat and has a long service life.

Abstract: One of the thermophysical characteristics of metals and alloys is the specific heat capacity. It is measured, as a rule, experimentally, which determines the high cost and labor intensity of this approach. A model has been developed for calculating the specific heat capacity of chemical elements and their compounds. The calculation results are in satisfactory agreement with the experimental data of other authors (reference data). The simulation results are used to calculate the thermal state of gas turbine parts. It can also be used in alloy design.

Abstract: Reducing the melting point, in creasing the thermal stability limit, and enhancing the specific heat capacity of molten salt are the research hotspots in the field of medium and high temperature energy storage in recent years. From the perspectives of the melting point, thermal stability limit, and specific heat capacity of nitrates, we summarize the melting point, thermal stability limit, and specific heat capacity enhancement of molten salts with different compositions and ratios. The melting points of molten salt with different compositions and ratios are compared. Furthermore, the enhancing effect of various nanomaterials on molten salt is elucidated. The application of nitrate molten salt is also summarized to provide a reference for the research and application of novel molten salts. Keywords: Nitrate Molten Salt; Melting Point; Thermal Stability Limit; Specific Heat Capacity; Application

Abstract: Experimental analyses are performed to determine thermal conductivity, thermal diffusivity and volumetric specific heat with transient plane source method on hollow sphere structures. Single-sided testing is used on different samples and different surfaces. Results dependency on the surface is observed.

Abstract: The paper is devoted to the study of thermal parameters (specific heat capacity, diffusivity and thermal conductivity) changes after thermally induced aging of BMC Mensolite 3100. Results of several measurements are statistically treated. From obtained results it is visible the greatest correlation in the diffusivity values, i.e. the heat irradiation effect is the smallest on the diffusivity values dispersion, the influence of the heat irradiation on the thermal capacity has approximately the same trend as the thermal conductivity. From the starting point represented by the virgin sample both values decrease and for the sample heated at 300°C it is visible an increase of the above mentioned values under investigation. Results are interpreted by using of the thermogravimetric analysis (TGA). All physical values under this investigation have a dominant decreasing tendency after the thermal treatment described.

Abstract: In this work, we consider is the single-particle bound-state problem. A single-particle moves in the absence of the anharmonics oscillator asymmetric potential. The bound-state problem then is to solve the partition function for single-particle in the presence of anharmonics oscillator asymmetric potential. The factor second exponential function of partition function of particle bound in the anharmonics oscillator asymmetric potential can also be expanded in power series of the temperature and parameter , , and is the position of single-particle bound-state problem and using the integrate Gaussian. The purpose of this works, we will compute the partition function as a function of temperature, entropy, specific heat capacity and standard deviation which depend on the parameter and frequency.

Abstract: In this research, a fundamental quantum mechanics and statistical mechanic bound-state problem of harmonics oscillator cosine asymmetric was considered by using partition function method. From the study, it found that the internal energy, the entropy and the specific heat capacity of particle vibration bound-state under harmonics oscillator cosine asymmetric potential were increased as the increasing of the parameters of μ, η, and β. While an increasing of parameter α affected to the decreasing of the entropy and the heat capacity. In addition, the increasing values of the entropy and the specific heat capacity value were depended on the decreasing of the parameter α value.

Abstract: For the past fifteen years, there has been considerable interest in the use of nanofluids in various fields mainly in heat transfer applications. This paper investigated thermophysical properties of activated carbon nanofluids using hexane, water and ethylene glycol (EG) as base fluids. Experimental and qualitative observational tests were conducted to study the viscosity, specific heat capacity and stability of the nanofluids using arabinogalactan (ARB), sodium lauryl sulphate (SDS) and TritonX-114 as stabilising agents. The results revealed that the addition of ARB to activated carbon-water (C/H₂O) nanofluids yielded nanofluid stability for up to 39 days. However, ARB decreased the heat capacity of C/H₂O nanofluid. C/H₂O nanofluid viscosity decreased with an increase in shear rate. On the other hand, results revealed that C/C₆H₁₄ viscosity increased with the increase in shear rate specifically for high shear rate values. C/H₂O heat capacity was enhanced by 6.1% compared to C/EG that decreased by 6.3%. Keywords: Nanofluids; Viscosity; Specific heat capacity; Surfactant; Stability.

Abstract: Parts of thermal physical properties of Al-Si8-Cu2-Mg alloy were studied. The curves were plotted showing the relationship between density, specific heat capacity, coefficient of thermal expansion and the variation of temperature for the first time with this alloy. The results show that the density was decreased when the temperature was raised, but the specific heat capacity and the coefficient of thermal expansion were first increased and then decreased. The solidus-liquidus temperatures, latent heat of fusion were studied, and the results show that the melting temperature range of this alloy was 507-596°C.