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15 articles for “enthalpy change”
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Natural Bond Orbital, Bond Order and Frequency based Study of Hydrogen Bond Formation in Different Glycols-Water Complex
Abstract: Natural bond orbital (NBO) analysis, natural atomic orbital (NAO) analysis, Wiberg bond order, vibrational frequency, free energy and enthalpy changes for hydrogen bond formation in different polyethylene glycol + water complex and dipropylene glycol + water complex have been performed by Hatree Fock (HF) method, second order Møller–Plesset perturbation theory (MP2) and Density Functional Theory (DFT) using 6-31++G(d,p) basis set. In order to describe hydrogen bond interaction appropriately, B3LYP DFT-D, …
Published in Journal of Modern Chemistry & Chemical Technology · Vol. 4, Issue 1, 2013 · pp. 1–20 Read article
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Study of the Hammett equation for oxidation of 2 – Hydroxy – 1 - Naphthalidene Anil and para substituted chloroanils by potassium bromate in acid medium
Abstract: The kinetics of oxidation of the Schiff base and its substituted anils by potassium bromate in aquo-acetic acid medium has been studied in this work. The study of thermodynamic parameters is done, and the rate constants for the reaction are determined. The plot of log{ks/k0} against the substituent constant (ï³ ) is plotted for para and meta substitution and the reaction constant (ï²) is calculated. The plot of ï„H against …
Published in Journal of Modern Chemistry & Chemical Technology · Vol. 7, Issue 2, 2016 · pp. 1–4 Read article
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The thermodynamic studies of 6-(4-chlorophenyl)-1, 2, 3, 4-tetrahydro-2,4-dioxopyrimidine-5-carbonitrile in 60% DMSO in the temperature range 298 to 313 K
Abstract: Densities and viscosities of 6-(4-chlorophenyl)-1, 2, 3, 4-tetrahydro-2,4-dioxopyrimidine-5-carbonitrile have been measured at different concentration in 60% dimethyl sulphoxide (DMSO) in the temperature range 298 to 313 K. The John-Dole equation was used to determine the viscosity. Gibb’s free energy (∆G), entropy change (∆S) and enthalpy change (∆H) were evaluated from relative viscosity . The negative sign of ∆G and ∆H and positive sign of ∆S indicates the spontaneity of reaction …
Published in Journal of Polymer & Composites · Vol. 8, Issue 2, 2020 · pp. 78–81 Read article
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Polymer Phase Change Materials: Innovations, Applications, and Future Directions
Abstract: Polymer-based phase change materials represent a significant advancement in energy storage and thermal management technologies due to their ability to absorb, store, and release heat during phase transitions. This article reviews recent innovations in polymer phase change materials, focusing on the synthesis, characterization, and performance enhancement techniques. The development of polymer composites with enhanced thermal conductivity, improved phase change enthalpy, and extended thermal cycling stability is discussed. Additionally, the integration …
Published in Journal of Refrigeration, Air conditioning, Heating and ventilation · Vol. 11, Issue 2, 2024 · pp. 1–7 Read article
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Calcareous Soil as a Promising Adsorbent to Remove Fluoride from Aqueous Solution: Equilibrium, Kinetic and Thermodynamic Study
Abstract: Normal 0 false false false EN-US X-NONE X-NONE MicrosoftInternetExplorer4 In this work, the feasibility of employing calcareous soil to remove fluoride ions from its aqueous solutions was investigated under batch mode. The influence of solution pH, sorbent dose, initial fluoride concentration, contact time, stirring rate and temperature on the removal process were investigated. The equilibrium adsorption data were analyzed using Langmuir, Freundlich and Temkin isotherm models. The kinetics of fluoride …
Published in Journal of Modern Chemistry & Chemical Technology · Vol. 3, Issue 3, 2012 · pp. 1–21 Read article
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Synthesis of CaCl2.6H2O by Using Phase Diagram and Verification of its Ability to Remain as a Hexahydrate at Various Thermal Effects
Abstract: Antarcticite (CaCl2.6H2O) is one of the salt hydrate forms of Calcium chloride. It has a specific application in energy storage systems at ambient temperature, since its melting point is around 29ºC. During the conventional synthesis of Antarcticite, a risk of other hydrates crystallization is there. An experimental procedure is designed through binary melting phase diagram for selective crystallization of Antarcticite from aqueous CaCl2 solution. The melting and recrystallization behavior of …
Published in Journal of Alternate Energy Sources & Technologies · Vol. 6, Issue 3, 2015 · pp. 60–71 Read article
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Numerical Study of Melting Process of Phase Change Material Filled in Rectangular Cavity with Partially Active Walls
Abstract: This paper presents numerical investigation of melting process inside rectangular cavity with partially active walls. Enthalpy porosity approach is used to simulate convection dominated melting inside rectangular cavity. Gallium is used as phase change material. Numerical model is validated with available experimental results. Numerical investigation is carried out to investigate the influence on melting behaviour of phase change material for relative positions of hot and cold walls. Results show that …
Published in Journal of Thermal Engineering and Applications · Vol. 4, Issue 2, 2017 · pp. 32–38 Read article
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Corrosion and Corrosion Protection of Cast iron due to Bio-organism
Abstract: Cast iron is a high tensile strength metal. It is generally used for making tools, pipe fitting, electrical fitting equipment and rail track. It interacts with corrosive substances to develop electrochemical cell on their interface. Corrosive substances are acids, bases, salts, bio-wastes, particulates and pollutants. These substances produce hostile medium for materials. These harmful wastes discharge by industries, households, agricultural, urbanization, development of infrastructure, construction works, thermal power stations, hydropower, …
Published in Journal of Modern Chemistry & Chemical Technology · Vol. 16, Issue 2, 2025 · pp. 105–114 Read article
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Analysis of Ageing and Degradation Behavior of Polyamide-12 for Sustainable Additive Manufacturing
Abstract: Additive Manufacturing (AM), particularly High-Speed Sintering (HSS), has emerged as a transformative technology capable of producing complex thermoplastic parts with high efficiency and minimal material waste. The HSS process involves selective deposition of radiation-absorbing ink followed by infrared heating to consolidate polymer powders-most commonly polyamide-12 (PA12). While PA12 is widely used due to its excellent thermal stability and mechanical properties, the sustainability of HSS strongly depends on the reuse of …
Published in Journal of Polymer & Composites · Vol. 14, Issue 2, 2026 · pp. 136–154 Read article
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Polymer–Gel Composite Phase Change Materials: A Functional Polymer Composite Approach for Solar-Thermal Energy Storage in Building Facades
Abstract: This study investigates polymer–composite phase change materials (PCMs) in the form of polymer–gel hybrids as multifunctional systems for solar–thermal energy storage in building façades. Paraffin- and PEG-based PCMs were embedded into polyurethane and acrylic gel matrices to create shape-stabilized polymer–composites with high PCM loading (70–80 wt%). Differential Scanning Calorimetry (DSC) confirmed distinct melting/freezing transitions at ~56°C (paraffin) and ~42°C (PEG), with enthalpy values of 120–150 J/g, closely matching theoretical predictions, …
Published in Journal of Polymer & Composites · Vol. 13, Issue 6, 2025 · pp. 36–51 Read article
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Selection of Working Fluid for Organic Rankine Cycle by Energy and Exergy, For Low Temperature Low Enthalpy Dholera Geothermal Reservoir
Abstract: In today’s scenario of increasing energy demand, it is high time to give emphasis on renewable energy sources. The conventional energy sources that humanity is depending upon today are not only depleting, but also cause significant environmental impact. The burning of coal and fossil fuels causes serious air pollution and several major cities are already under deep threat due to the increasing amount of pollution. Future predictions show an exponential …
Published in Emerging Trends in Chemical Engineering · Vol. 3, Issue 2, 2016 · pp. 1–10 Read article
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Dodecahedron Methane Hydrate Cage Structure – An Ab initio Study
Abstract: Comparative study of 512clathrate hydrate cage having different numbers of methane guest molecules encapsulation is carried out by calculating interaction energy, encapsulation energy and thermo-chemical stability parameters using density functional theory-based calculation with B3LYP functional and 6-31G(d) basis set. Nuclear magnetic resonance spectroscopy(NMR), Infrared spectroscopy (IR spectroscopy) and Raman spectroscopy of empty and methane encapsulated 512clathrate hydrate cages, change in Gibbs free energy and methane hydrate formation enthalpy are predicted …
Published in Journal of Petroleum Engineering & Technology · Vol. 2, Issue 1-3, 2012 · pp. 51–64 Read article
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Effect of Gamma and Electron Beam Irradiations on Crystalline and Gelatinization Properties of Edible Potato Starch
Abstract: Exposure of food material to radiation causes changes in crystalline (damage of crystal structure / lattice distortion), and gelatinization (digestive)properties. Potato starch (PS) is one of the important globally used food supplement in different forms like chips, curries, cusins etc. During its use the PS is exposed to radiations, altering its molecular structure (due to chain cleavages) and bring changes in structural and physical properties ; sometimes ill – effects …
Published in Journal of Polymer & Composites · Vol. 14, Issue 2, 2026 · pp. 113–127 Read article
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Corrosion and Corrosion Protection of Unio in Carbonic Acid Medium
Abstract: Unio is a calciferous animal, and its outer surface is made of calcium carbonate. It usually happens in sources of sweet water. They create carbonic acid by absorbing carbon dioxide. It changes the pH of sweet water sources thus water becomes acidic. It develops corrosive environment for Unio. Carbonic acid interacts with Unio to form corrosion cells on the interface of Unio. This acid oxidizes calcium carbonate into calcium ions …
Published in Journal of Water Pollution & Purification Research · Vol. 12, Issue 1, 2025 · pp. 22–31 Read article
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Electron beam irradiation studies of polyethylene maleic anhydride on their Chemical and Thermal properties.
Abstract: The electron beam (e-beam) irradiation effects on polyethylene maleic anhydride (MANPE) are investigated by spectroscopic and thermal methods. The MANPE irradiated with electron beam to a radiation dose of 30, 60 and 90 K Gy and the resultant changes in their chemical structure and thermal properties have been investigated by Electron spin resonance (ESR), Fourier transform infrared spectroscopy (FTIR), differential scanning calorimetry (DSC), X-ray diffraction (XRD) and scanning electron microscopy …
Published in Journal of Polymer & Composites · Vol. 6, Issue 2, 2018 · pp. 17–30 Read article