scholarly journals Specific Heat Capacity of Confined Water in Extremely Narrow Graphene Nanochannels

2021 ◽  
Vol 9 ◽  
Author(s):  
Runfeng Zhou ◽  
Xinyi Ma ◽  
Haoxun Li ◽  
Chengzhen Sun ◽  
Bofeng Bai
Keyword(s):  
Heat Capacity ◽  
Specific Heat ◽  
Specific Heat Capacity ◽  
Bulk Water ◽  
Confined Water ◽  
Energy Applications ◽  
Physical Mechanisms ◽  
Nanoconfined Water ◽  
Auto Correlation Function ◽  
Dynamics Simulations

Specific heat capacity of extremely confined water determines its performance in the heat transfer as the sizes of devices decrease to nanoscales. Here, we report the basic data of the specific heat capacity of water confined in narrow graphene nanochannels below 5 nm in height using molecular dynamics simulations. The results show that the specific heat capacity of confined water is size-dependent, and the commensurability effect of the specific heat capacity presents as the confinement decreases to 1.7 nm. The deviation of specific heat capacity of confined water with that of bulk water is attributed to the variation of configuration features, including density distribution and hydrogen bonds, and vibration features, including velocity auto-correlation function and vibrational density of states. This work unveils the confinement effects and their physical mechanisms of the specific heat capacity of nanoconfined water, and the data provided here have wide prospects for energy applications at nanoscales.

A critical review of specific heat capacity of hybrid nanofluids for thermal energy applications

2021 ◽  
pp. 116890
Author(s):  
Humphrey Adun ◽  
Ifeoluwa Wole-Osho ◽  
Eric C. Okonkwo ◽  
Doga Kavaz ◽  
Mustafa Dagbasi
Keyword(s):  
Heat Capacity ◽  
Specific Heat ◽  
Specific Heat Capacity ◽  
Thermal Energy ◽  
Critical Review ◽  
Energy Applications ◽  
Hybrid Nanofluids

Thermal Conductivity and Specific Heat Capacity of Carbon Nanotube Bundles

2007 ◽  
Author(s):  
John Shelton ◽  
Frank Pyrtle
Keyword(s):  
Thermal Conductivity ◽  
Carbon Nanotubes ◽  
Heat Capacity ◽  
Carbon Nanotube ◽  
Specific Heat ◽  
Specific Heat Capacity ◽  
Element Analysis ◽  
Single Walled Carbon ◽  
Nanotube Bundles ◽  
Dynamics Simulations

Carbon nanotubes (CNTs) have been thoroughly documented to demonstrate superior heat transfer properties. It has also been determined that these properties decrease substantially as overall dimensions increase from the nanoscale to the microscale. Using non-equilibrium molecular dynamics simulations and finite element analysis, the influence of both internal and external thermal boundary resistance effects on the thermal conductivity and specific heat capacity of single walled carbon nanotube bundles were investigated. Comparisons were made between accepted property values for single CNTs and for CNT bundles. Also, energy transfer between varying sized bundles of single-walled carbon nanotubes (SWCNTs) and a surrounding pressure-driven Lennard-Jones (LJ) fluid were calculated.

Enhanced Specific Heat Capacity of Molten Salts Using Organic Nanoparticles

2011 ◽  
Author(s):  
Byeongnam Jo ◽  
Debjyoti Banerjee
Keyword(s):  
Heat Capacity ◽  
Physical Properties ◽  
Specific Heat ◽  
Specific Heat Capacity ◽  
Organic Nanoparticles ◽  
Energy Applications ◽  
Energy Demands ◽  
Liquid Phases ◽  
Graphite Nanoparticles ◽  
Thermo Physical Properties

In this study we explore the material properties of carbonate salt eutectics that melt at high temperatures (exceeding 480 °C). These salt eutectics demonstrated anomalous enhancement in the specific heat capacity in both solid and liquid phases — when mixed with carious organic nanoparticles such as carbon nanotubes (CNT) and graphite nanoparticles. Theses experimental measurements are compared with previous reports in the literature for exploring the effect of the synthesis protocol on the resulting thermo-physical properties of these nanomaterials. The enhancement of the thermo-physical properties on mixing with nanoparticles is of significant interest in reducing the cost of thermal energy storage (TES) devices and systems. TES can be utilized for levelizing peaks in cyclical energy demands (or duties) that is typical of renewable energy applications where the input energy source may be intermittent (e.g., solar thermal); as well as in geothermal and nuclear energy applications.

Enhancement of thermophysical coefficients in nanofluids: A simulation study

2020 ◽  
Vol 34 (25) ◽  
pp. 2050222
Author(s):  
Xiandai Cui ◽  
Xiaomin Cheng ◽  
Hong Xu ◽  
Bei Li ◽  
Jiaoqun Zhu
Keyword(s):  
Molecular Dynamics ◽  
Heat Capacity ◽  
Specific Heat ◽  
Specific Heat Capacity ◽  
Thermophysical Properties ◽  
Phase Change Materials ◽  
Nonequilibrium Molecular Dynamics ◽  
Microscopic Mechanism ◽  
Dynamics Simulations ◽  
First Time

Molten salts constitute one kind of PCMs (Phase Change Materials) widely used in concentrating solar power facilities for heat storage and heat transfer. This paper aims to simulate nanofluid PCMs with molecular dynamics method. Concretely, the thermophysical properties of a nanofluid of KNO3 doped with SiO2 nanoparticle are investigated by equilibrium and nonequilibrium molecular dynamics simulations. For the first time, these properties of a nanofluid in the family of PCMs are calculated. The density, thermal expansion coefficient, specific heat capacity, thermal conductivity, and viscosity are characterized as functions of the SiO2 nanoparticle concentration. The effect of the SiO2 nanoparticle size on the nanofluid’s properties is also investigated. The simulation results present an enhancement of the thermophysical properties, especially for the specific heat capacity, in good agreement with the existing experimental results on a representative nanofluid PCM, and open prospects for the understanding of microscopic mechanism leading to such enhancements.

Experimental Study on the Specific Heat Capacity Measurement of Water-Based Al2O3-Cu Hybrid Nanofluid by using Differential Thermal Analysis Method

2019 ◽  
Vol 15 ◽  
Author(s):  
Andaç Batur Çolak ◽  
Oğuzhan Yıldız ◽  
Mustafa Bayrak ◽  
Ali Celen ◽  
Ahmet Selim Dalkılıç ◽  
...  
Keyword(s):  
Heat Capacity ◽  
Specific Heat ◽  
Specific Heat Capacity ◽  
Thermophysical Properties ◽  
Volume Concentration ◽  
Pure Water ◽  
Heat Capacity Measurement ◽  
Experimental Results ◽  
Hybrid Nanofluid ◽  
Capacity Measurement

Background: Researchers working in the field of nanofluid have done many studies on the thermophysical properties of nanofluids. Among these studies, the number of studies on specific heat are rather limited. In the study of the heat transfer performance of nanofluids, it is necessary to increase the number of specific heat studies, whose subject is one of the important thermophysical properties. Objective: The authors aimed to measure the specific heat values of Al2O3/water, Cu/water nanofluids and Al2O3-Cu/water hybrid nanofluids using the DTA method, and compare the results with those frequently used in the literature. In addition, this study focuses on the effect of temperature and volume concentration on specific heat. Method: The two-step method was used in the preparation of nanofluids. The pure water selected as the base fluid was mixed with the Al2O3 and Cu nanoparticles and Arabic Gum as the surfactant, firstly mixed in the magnetic stirrer for half an hour. It was then homogenized for 6 hours in the ultrasonic homogenizer. Results: After the experiments, the specific heat of nanofluids and hybrid nanofluid were compared and the temperature and volume concentration of specific heat were investigated. Then, the experimental results obtained for all three fluids were compared with the two frequently used correlations in the literature. Conclusion: Specific heat capacity increased with increasing temperature, and decreased with increasing volume concentration for three tested nanofluids. Cu/water has the lowest specific heat capacity among all tested fluids. Experimental specific heat capacity measurement results are compared by using the models developed by Pak and Cho and Xuan and Roetzel. According to experimental results, these correlations can predict experimental results within the range of ±1%.

Development of the room temperature protocol based on room temperature ionic liquids and surfactant ionic liquids for the synthesis of derivatives of 2-amino-thiazoles and thermo-physical analysis of the synthesized derivatives using TGA-DSC.

2020 ◽  
Vol 10 ◽  
Author(s):  
Chandrakant Sarode ◽  
Sachin Yeole ◽  
Ganesh Chaudhari ◽  
Govinda Waghulde ◽  
Gaurav Gupta
Keyword(s):  
Thermal Analysis ◽  
Heat Capacity ◽  
Ionic Liquids ◽  
Specific Heat ◽  
Specific Heat Capacity ◽  
Room Temperature ◽  
Heat Capacity Data ◽  
General Strategy ◽  
Capacity Data ◽  
Derivatives Of

Aims: To develop an efficient protocol, which involves an elegant exploration of the catalytic potential of both the room temperature and surfactant ionic liquids towards the synthesis of biologically important derivatives of 2-aminothiazole. Objective: Specific heat capacity data as a function of temperature for the synthesized 2- aminothiazole derivatives has been advanced by exploring their thermal profiles. Method: The thermal gravimetry analysis and differential scanning calorimetry techniques are used systematically. Results: The present strategy could prove to be a useful general strategy for researchers working in the field of surfactants and surfactant based ionic liquids towards their exploration in organic synthesis. In addition to that, effect of electronic parameters on the melting temperature of the corresponding 2-aminothiazole has been demonstrated with the help of thermal analysis. Specific heat capacity data as a function of temperature for the synthesized 2-aminothiazole derivatives has also been reported. Conclusion: Melting behavior of the synthesized 2-aminothiazole derivatives is to be described on the basis of electronic effects with the help of thermal analysis. Additionally, the specific heat capacity data can be helpful to the chemists, those are engaged in chemical modelling as well as docking studies. Furthermore, the data also helps to determine valuable thermodynamic parameters such as entropy and enthalpy.

scholarly journals Influence of alkaline modification on selected properties of banana fiber paperbricks

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Abayomi A. Akinwande ◽  
Adeolu A. Adediran ◽  
Oluwatosin A. Balogun ◽  
Oluwaseyi S. Olusoju ◽  
Olanrewaju S. Adesina
Keyword(s):  
Thermal Conductivity ◽  
Heat Capacity ◽  
Specific Heat ◽  
Specific Heat Capacity ◽  
Moisture Absorption ◽  
Water Volume ◽  
Banana Fiber ◽  
Fiber Loading ◽  
Banana Fibers ◽  
Alkaline Modification

AbstractIn a bid to develop paper bricks as alternative masonry units, unmodified banana fibers (UMBF) and alkaline (1 Molar aqueous sodium hydroxide) modified banana fibers (AMBF), fine sand, and ordinary Portland cement were blended with waste paper pulp. The fibers were introduced in varying proportions of 0, 0.5, 1.0 1.5, 2.0, and 2.5 wt% (by weight of the pulp) and curing was done for 28 and 56 days. Properties such as water and moisture absorption, compressive, flexural, and splitting tensile strengths, thermal conductivity, and specific heat capacity were appraised. The outcome of the examinations carried out revealed that water absorption rose with fiber loading while AMBF reinforced samples absorbed lesser water volume than UMBF reinforced samples; a feat occasioned by alkaline treatment of banana fiber. Moisture absorption increased with paper bricks doped with UMBF, while in the case of AMBF-paper bricks, property value was noted to depreciate with increment in AMBF proportion. Fiber loading resulted in improvement of compressive, flexural, and splitting tensile strengths and it was noted that AMBF reinforced samples performed better. The result of the thermal test showed that incorporation of UMBF led to depreciation in thermal conductivity while AMBF infusion in the bricks initiated increment in value. Opposite behaviour was observed for specific heat capacity as UMBF enhanced heat capacity while AMBF led to depreciation. Experimental trend analysis carried out indicates that curing length and alkaline modification of fiber were effective in maximizing the properties of paperbricks for masonry construction.

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