Thermodynamic Research Articles

Journal Vol – 15 No -7, July 2020 Journal > Journal > Journal Vol – 15 No -7, July 2020 > Page 6 PERFORMANCE AND EMISSION CHARACTERISTICS OF GASOLINE-ETHANOL BLENDS ON PFI-SI ENGINE Authors: D.Vinay Kumar ,G.Samhita Priyadarsini,V.Jagadeesh Babu,Y.Sai Varun Teja, DOI NO: https://doi.org/10.26782/jmcms.2020.07.00051 admin July 26, 2020 Abstract: Alcohol based fuels can be produced from renewable energy sources and

Journal Vol – 15 No -7, July 2020 Journal > Journal > Journal Vol – 15 No -7, July 2020 > Page 6 PERFORMANCE AND EMISSION CHARACTERISTICS OF GASOLINE-ETHANOL BLENDS ON PFI-SI ENGINE Authors: D.Vinay Kumar ,G.Samhita Priyadarsini,V.Jagadeesh Babu,Y.Sai Varun Teja, DOI NO: https://doi.org/10.26782/jmcms.2020.07.00051 admin July 26, 2020 Abstract: Alcohol based fuels can be produced from renewable energy sources and

Adsorption of Cadmium (II) ions from aqueous solutions using Poly(amidoamine)/ multi-walled carbon nanotubes doped Poly(vinylidene fluoride-co-hexafluoropropene) composite membrane

Composite membranes consisting of Poly(vinylidene fluoride-co-hexafluoropropene) (PVDF-HFP) blended with functionalised multi-walled carbon nanotubes (MWCNTs) and poly-amidoamine (PAMAM) were prepared using a phase inversion technique for adsorptive elimination of Cd (II) ions from contaminated water samples. Upon the addition of PAMAM-MWCNTs on PVDF-HFP, a stable, microporous structure with enhanced surface area and hydrophilic composite membranes were obtained; as confirmed by Focused Ion Beam Scanning electron microscopy (FIB-SEM), Fourier transform infrared (FTIR), Thermogravimetric analysis (TGA), Brunauer-Emmett-Teller (BET) analysis and contact angle measurements. The pH, adsorption isotherm, thermodynamic parameters and reusability of the composite membranes were investigated in batch experiments. The maximum adsorption capacity of 1 wt.% PAMAM-MWCNTs/PVDF-HFP composite membrane calculated by Langmuir model was 167 mg/g at 25 oC and pH 6.5. All composite membranes demonstrated that the Cd(II) ions adsorption conformed to Freundlich model (R2 = 0.999), which suggests that the adsorption process is multilayer. In addition, the thermodynamic parameters indicated that the adsorption process is spontaneous and endothermic in nature. The adsorption capacity of 1 wt.% PAMAM-MWCNTs/PVDF-HFP composite membrane remained above 90% after four reusability cycles, as confirmed by Inductively coupled plasma-optical emission spectrometry (ICP-OES) analysis. The 1 wt.% PAMAM-MWCNTs/PVDF-HFP composite membrane exhibited higher selectivity coefficients towards Cd(II) in Cu(II), Zn(II) and Ni(II) binary metal solutions.

Comparative study of electrolyte thermodynamic models for carbon dioxide solubility in water at high pressure

Comparative study of electrolyte thermodynamic models for carbon dioxide solubility in water at high pressure

Preparation and thermodynamic equilibrium analysis of neodymium disilicate via sol-precipitation and sintering

Preparation and thermodynamic equilibrium analysis of neodymium disilicate via sol-precipitation and sintering

Hyperbolic ring based formulation for thermo field dynamics, quantum dissipation, entanglement, and holography

The classical and quantum formulations for open systems related to dissipative dynamics are constructed on a complex hyperbolic ring, following universal symmetry principles, and considering the double thermal fields approach for modeling the system of interest, and the environment. The hyperbolic rotations are revealed as an underlying internal symmetry for the dissipative dynamics, and a chemical potential is identified as conjugate variable to the charge operator, and thus a grand partition function is constructed. As opposed to the standard scheme, there are not patologies associated with the existence of many unitarity inequivalent representations on the hyperbolic ring, since the whole of the dissipative quantum dynamics is realized by choosing only one representation of the field commutation relations. Entanglement entropy operators for the subsystem of interest and the environment, are constructed as a tool for study the entanglement generated from the dissipation. The holographic perspectives of our results are discussed.

Temperature Variation of Chaotic Optical Field in Quantum Dissipation Channel and Diffusion Channel

In this paper we discuss the temperature variation of a new chaotic optical field after it passes through a single-mode quantum dissipation and diffusion channel respectively. Using the entangled state representation and the technique of integration within ordered product (IWOP) of operators, we solve the master equations and obtain the new output fields. We show the final explicit forms of the new output fields by detailed derivation. By virtue of thermo dynamics theory at finite temperature, we finally conclude the results of temperature variation of chaotic optical field both in quantum dissipation channel and diffusion channel.

Phase Equilibria in the Formation of Hydrates in Methane Or Carbon Dioxide + Water Systems Using Isofugacity and Gibbs Energy Minimization

Gas hydrates are crystalline structures formed by water molecules and compounds of low molecular weights, being formed under suitable conditions of pressure and temperature. Although initially considered as inconveniences to the natural gas industries, they are currently considered as promising alternatives for solving some important global issues, such as contributing to the reduction of effects caused by the greenhouse gases. This concern related to the control of emissions of polluting gases has mobilized hundreds of countries that, at the United Nations Climate Change Conference (COP), agreed to reduce emissions of carbon dioxide and other gases by 2100. However, despite several strategies in the reduction of carbon dioxide emissions have been proposed, many rely on political incentives and substantial investments to convert pre-existing technologies to clean technologies, making such applicability and adaptability problematic. Thus, innovative Carbon Capture and Storage (CCS) techniques are being studied, which considers the use of gas hydrates formation to trap these gases, presents perspectives of lower costs and low environmental damages, promising to overcome the above mentioned problem, besides capturing and storing adequately the carbon dioxide and methane emitted. The need for robust evaluation of the thermodynamic equilibrium of hydrate-containing systems arises in order to make the proposal feasible and used on a large scale. The present work extensively solidifies this assessment of hydrate phase equilibria by proposing the isofugacity and Gibbs energy minimization criteria coupled to the nonlinear programming for the calculation of phase equilibria in the formation of methane and carbon dioxide hydrates. The Soave-Redlich-Kong cubic equation (SRK) was used to calculate the liquid and gaseous phases, and the Van der Waals and Platteeuw models were used to describe the solid phase of the hydrate. The procedure was implemented in the General Algebraic Modeling System (GAMS) software and in the CONOPT3 solver, with some numerical procedures performed in Microsoft Office Excel. The comparison between the results obtained from the present study by the isofugacity criterion and experimental data has been carried out, allowing concluding the satisfactory prediction of the phase equilibria behavior of systems containing hydrates.

Tangible Phenomenological Thermodynamics

In this paper, the foundations of classical phenomenological thermodynamics are being thoroughly revisited. A new rigorous basis for thermodynamics is laid out in the main text and presented in full detail in the appendix. All relevant concepts, such as work, heat, internal energy, heat reservoirs, reversibility, absolute temperature and entropy, are introduced on an abstract level and connected through traditional results, such as Carnot's Theorem, Clausius' Theorem and the Entropy Theorem. The paper offers insights into the basic assumptions one has to make in order to formally introduce a phenomenological thermodynamic theory. This contribution is of particular importance when applying phenomenological thermodynamics to systems, such as black holes, where the microscopic physics is not yet fully understood. Altogether, this work can serve as a basis for a complete and rigorous introduction to thermodynamics in an undergraduate course which follows the traditional lines as closely as possible.

Thermodynamic optimization of heat transfer in internal gas flow with conical ring inserts

El uso de insertos estáticos permite el diseño de intercambiadores de calor de menor volumen, pero también pueden ser implementados en equipos existentes para mejorar su rendimiento. En este trabajo se desarrolla una metodología para la optimización termodinámica de insertos cónicos para el calentamiento de gases en tuberías a partir de un modelo algebraico adimensional. Se plantean y resuelven dos casos de optimización: el diseño de un intercambiador de calor en donde las únicas variables fijas son la temperatura de entrada y la transferencia de calor requerida. El segundo caso es la incorporación de los insertos a un intercambiador existente, en donde la temperatura de carga, flujo de masa y las características geométricas de la tubería son los parámetros fijos. Como resultados se presenta un análisis paramétrico en donde se estudia la influencia de distintos parámetros de diseño en la temperatura de descarga y la irreversibilidad termodinámica. Luego se presentan los resultados del proceso de optimización para distintas combinaciones de parámetros, y se discute las tendencias encontradas en las configuraciones óptimas. Los resultados son aplicados en un ejemplo para ilustrar el interés práctico de la metodología. Se encontró que para ambos casos de optimización las configuraciones óptimas corresponden a la mínima severidad de los insertos, mientras que los diseños óptimos corresponden siempre a la mínima relación de aspecto posible (L/D) para las tuberías, mientras que el número de tubos, contemplado en el número de Reynolds, se ajusta para satisfacer la temperatura de descarga

소용량 수소액화 파일럿 플랜트 구축을 위한 공정의 열역학 해석

소용량 수소액화 파일럿 플랜트 구축을 위한 공정의 열역학 해석

Two-body Wear and Hardness of New Generation Artificial Resin Teeth.

The purpose of this study was to evaluate two-body wear and hardness of new generation artificial resin teeth. Ten specimens of four different artificial resin teeth (nanofill composite, nanohybrid composite, microfiller reinforced acrylic and highly modified acrylic) were prepared. Specimens were thermodynamically loaded in a dual-axis chewing simulator (50N, 240,000 cycles, 1.6 Hz, 5/55°C thermocycle). The wear loss was analyzed by using plaster replicas and 3D laser scanner. Vickers hardness was determined before and after thermodynamic loading. Mean Vickers hardness values of highly modified acrylic resin teeth were statistically significantly lower than nanohybrid composite (p⟨0.001), nanofilled composite (p⟨0.001) and microfiller reinforced acrylic resin teeth (p⟨0.001). Mean wear loss of highly modified and microfiller reinforced acrylic resin teeth were statistically significantly lower than nanohybrid composite (p⟨0.001) and nanofilled composite (p⟨0.001) resin teeth. There was a statistically significant difference in wear among the materials. The correlation between hardness and wear was not statistically significant.

Investigation of the discontinuous precipitation of U-Nb alloys via thermodynamic analysis and phase-field modeling

U-Nb’s discontinuous precipitation, γmatrixbcc→αcellularorth+γcellular′bcc, is intriguing in the sense that it allows formation and growth of the metastable γ′ phase during the course of its occurrence. Previous attempts to explain the thermodynamic origin of U-Nb’s discontinuous precipitation hypothesized that the energy of α forms an intermediate common tangent with the first potential of the double-well energy of γ at the γ′ composition. In this work, we examine different possible mechanisms by which the discontinuous precipitation product in the U-Nb system can be stabilized. We put forward a mechanism by which the bulk free energy of the γ can develop a non-monotonic dependency with composition. Additionally we posit that local contributions due to lattice mismatch between the α and γ phases may be responsible for the generation of metastable states that may stabilized by thermodyna mics as well as by kinetics. Our work suggests that local misfit strain tends to play a crucial role in the growth of the discontinuous precipitation product. Depending on the magnitude of strain developed at the α/γ′ interfaces, either an increasing γ′ composition or a random distribution of γ′ compositions around the equiatomic value with respect to increasing temperature could be expected. Moreover, we show how it is possible to stabilize the discontinuous precipitation front through highly anisotropic and fast interface diffusion.

실로퓨트에 의한 아세나프텐 흡착에 관한 등온흡착식, 동역학 및 열역학적 특성

상용흡착제 실로퓨트에 의한 Taxus chinensis 유래 주요 타르 성분인 아세나프텐의 흡착 특성을 조사하였다. 초기 아세나프텐 농도, 흡착 온도 및 시간에 따른 흡착 데이터를 Langmuir, Freundlich, Temkin 및 Dubinin-Radushkevich 등온흡착식에 적용한 결과, Langmuir 등온흡착식이 가장 적합하였다. 동역학적 흡착 데이터는 유사 이차 속도식에 가장 잘 따름을 알 수 있었다. 열역학적 파라미터로부터 흡착 공정이 적합하며 비자발적 발열이었다. 등량흡착열은 흡착량에 의존하지 않아 실로퓨트의 표면에너지가 균일함을 알 수 있었다.

Investigation on the Synergistic Effect of Tetra Butyl Phosphonium Bromide with Poly(N-isopropylacrylamide) Based Kinetic Hydrate Inhibitor

The problem of clathrate hydrate plugging in flow pipes has been the most important issue in the off-shore exploitation since hydrates were found in transport facilities. In recent years, low dosage hydrate inhibitors have attracted much interest among researchers in place of thermodynamic hydrate inhibitors such as methanol and mono ethylene glycol (MEG). Poly-vinyl caprolactam and poly-isopropylacrylamide (PNIPAM) are among the hydrate inhibitors that are typically used for polymers containing amide groups. Furthermore, various kinds of polymer inhibitors containing amide group including tetrabutylphosphonium bromide(TBPB), which is a quaternary salt, were synthesized and studied in a methane gas hydrate environment. In this experiment, the injection of 0.1 wt% inhibitor at 276 K and 5 MPa was followed by stirring the water to induce nucleation. From the result, when PNIPAM alone was used as a single KHI, PNIPAM exhibited worst performance among the KHIs tested in this study. But the mixing of TBPB with PNIPAM further extended the induction time and reduced the CH4 hydrate growth rate. The real-time in situ Raman system used to understand the inhibition principle was recorded during CH4 hydrate formation, as a result, PNIPAM showed that the large hydrate cage affected, while TBPB prevented the CH4 molecule from occupying the small cage. TBPB was excellent synergist in blends with PNIPAM for kinetic hydrate inhibition of structure I forming CH4 hydrate.

Ionic Liquid Solvent Design Framework for Extraction of Phytochemicals using Microwave-Assisted Method

Computer aided molecular design (CAMD) has been used widely for solvent design. It is a reverse approach in the selection of solvents for real application. CAMD is suitable for ionic liquid solvent design due the vast possibilities of ionic liquid molecular structures to be identified. Ionic liquid has broad ranges of applications especially in separation especially in carbon capture and azeotropic separation. This is due to the unique structures of ionic liquid that can be tailored for specific product separation. This study focuses on ionic liquid design framework for phytochemical extraction, incorporating the prediction of the extraction yield using the microwave-assisted method. The framework was developed in several stages. Stage 1 identifies the user needs, problems and constraints as well as target properties. Stage 2 comprise of comprehensive database development for ionic liquid and phytochemical properties; while property models' library was developed in Stage 3. Stage 4 involved the development of solvent design algorithm for ionic liquid selection for the targeted process. In Stage 5, depending on the type of extraction method considered, either using normal Soxhlet or a microwave-assisted extraction, the extraction yield can be predicted using the process performance model. The performance model for the liquid extraction is the thermodynamic solid-liquid equilibria model while for the advanced extraction method, the model was obtained through optimization of the experimental extraction process. This systematic framework is illustrated through a case study involving flavonoid and phenolic acid extraction from Ortosiphon aureus. Based on the yield prediction, 1-ethyl-3- propylimidazoilum bromide can extract 29.92 mg/g and was selected as a solvent for Flavonoid extraction using Microwave-assisted extraction. The design framework is able to find the optimal ionic liquid candidate for the extraction process.

An investigation of the thermodynamic effect on the response of FG beam on elastic foundation

This study presents an analytical approach to investigate the thermodynamic behavior of functionally graded beam resting on elastic foundations. The formulation is based on a refined deformation theory taking into consideration the stretching effect and the type of elastic foundation. The displacement field used in the present refined theory contains undetermined integral forms and involves only three unknowns to derive. The mechanical characteristics of the beam are assumed to be varied across the thickness according to a simple exponential law distribution. The beam is supposed simply supported and therefore the Navier solution is used to derive analytical solution. Verification examples demonstrate that the developed theory is very accurate in describing the response of FG beams subjected to thermodynamic loading. Numerical results are carried out to show the effects of the thermodynamic loading on the response of FG beams resting on elastic foundation.

Thermal volume change of saturated clays: A fully coupled thermo-hydro-mechanical finite element implementation

The creep and consolidation behaviors of clays subjected to thermal cycles are of fundamental importance in the application of energy geostructures. This study aims to numerically investigate the physical mechanisms for the temperature-triggered volume change of saturated clays. A recently developed thermodynamic framework is used to derive the thermo-mechanical constitutive model for clays. Based on the model, a fully coupled thermo-hydro-mechanical (THM) finite element (FE) code is developed. Comparison with experimental observations shows that the proposed FE code can well reproduce the irreversible thermal contraction of normally consolidated and lightly overconsolidated clays, as well as the thermal expansion of heavily overconsolidated clays under drained heating. Simulations reveal that excess pore pressure may accumulate in clay samples under triaxial drained conditions due to low permeability and high heating rate, resulting in thermally induced primary consolidation. Results show that four major mechanisms contribute to the thermal volume change of clays: (i) the principle of thermal expansion, (ii) the decrease of effective stress due to the accumulation of excess pore pressure, (iii) the thermal creep, and (iv) the thermally induced primary consolidation. The former two mechanisms mainly contribute to the thermal expansion of heavily overconsolidated clays, whereas the latter two contribute to the noticeable thermal contraction of normally consolidated and lightly overconsolidated clays. Consideration of the four physical mechanisms is important for the settlement prediction of energy geostructures, especially in soft soils.

Thermodynamic analysis and applications of the Abraham solvation parameter model in the study of the solubility of some sulfonamides

Se investigó la solubilidad de sulfadiazina (SD), sulfamerazina (SMR) y sulfametazina (SMT) en mezclas codisolventes de octanol + metanol a 278,15 K, 298,15 y 313,15 K. En todos los casos, la solubilidad más baja de cada fármaco se obtuvo en octanol puro a 278,15 K. La solubilidad máxima depende de la polaridad del fármaco, por lo que SMR y SMT alcanzaron su máxima solubilidad en mezclas cosolventes ricas en metanol. Las funciones termodinámicas de solución se calcularon a partir de los datos experimentales de solubilidad, utilizando las ecuaciones de van’t Hoff y Gibbs, siguiendo el enfoque propuesto por Krug et al. La entalpía de la solución es positiva en todos los casos, lo cual es una indicación del proceso endotérmico con un marcado favorecimiento entrópico. La solubilidad teórica y la concentración letal media se calcularon utilizando el modelo de Abraham.

МАТЕМАТИЧЕСКОЕ МОДЕЛИРОВАНИЕ ПРОЦЕССОВ АЭРОГАЗОТЕРМОДИНАМИКИ СВЕРХЗВУКОВОГО ЛЕТАТЕЛЬНОГО АППАРАТА С ПРЯМОТОЧНЫМ ВОЗДУШНО-РЕАКТИВНЫМ ДВИГАТЕЛЕМ

МАТЕМАТИЧЕСКОЕ МОДЕЛИРОВАНИЕ ПРОЦЕССОВ АЭРОГАЗОТЕРМОДИНАМИКИ СВЕРХЗВУКОВОГО ЛЕТАТЕЛЬНОГО АППАРАТА С ПРЯМОТОЧНЫМ ВОЗДУШНО-РЕАКТИВНЫМ ДВИГАТЕЛЕМ

Synthesis of polysulfone beads impregnated withCa-sepiolite for phosphate removal

Former studies revealed that sepiolite thermally treated at high temperature have high adsorption capacity for phosphate. However, its micron size (75 micro-m) limits its application to water treatment. In this study, we synthesized sepiolite impregnated polysulfone (PSf) beads to separate it easily from an aqueous solution. PSf beads with different sepiolite ratios were synthesized and their efficiencies were compared. The PSf beads with 30% impregnated sepiolite (30SPL-PSf bead) possessed the optimum sepiolite ratio for phosphate removal. Kinetic, equilibrium, and thermodynamic adsorption experiments were performed using the 30SPL-PSf bead. Equilibrium adsorption was achieved in 24 h, and the pseudo-first-order model was suitable for describing the phosphate adsorption at different reaction times. The Langmuir model was appropriate for describing the phosphate adsorption onto the 30SPL-PSf bead, and the maximum adsorption capacity of the 30SPL-PSf bead obtained from the model was 24.48 mg-PO4/g. Enthalpy and entropy increased during the phosphate adsorption onto the 30SPL-PSf bead, and Gibb\'s free energy at 35 degree Celcius was negative. An increase in the solution pH from 3 to 11 induced a decrease in the phosphate adsorption amount from 27.30 mg-PO4/g to 21.54 mg-PO4/g. The competitive anion influenced the phosphate adsorption onto the 30SPL-PSf bead was in the order of NO3- > SO42- > HCO3-. The phosphate breakthrough from the column packed with the 30SPL-PSf bead began after ~2000 min, reaching the influent concentration after ~8000 min. The adsorption amounts per unit mass of 30SPL-PSf and removal efficiency were 0.775 mg-PO4/g and 61.6%, respectively. This study demonstrates the adequate performance of 30SPL-PSf beads as a filter for phosphate removal from aqueous solutions.