Papers by Keyword: Thermodynamic

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Authors: Cai Jun Zhang, Hao Wu, Ai Min Gao, Li Guang Zhu
Abstract: For Containing Titanium Stainless Steel, in Liquid Steel the Existence of the Element such as Ti, N, O Are Easily Generating High Melting Point Compounds Tin, Tio2, Etc. the Compounds Easily Deteriorate Slag. the Relationship of Tin between Solubility Product and Temperature in 409 Stainless Steel Is lg([%Ti][%N])=4.6-17036.9/T . the Relationship of Tio2 between Solubility Product and Temperature in 409 Stainless Steel Is lg([%Ti][(%O)2])=11.6-35728/T .The Relationship of Al2O3 between Solubility Product and Temperature in 409 Stainless Steel Is lg([%Al]2[%O]3)=20.2-62787.9/T .Protective Slag Contains Compounds of B2O3 Mno and Fe2O3 Can Solve the Problem of “floater”.
Authors: Xue Ying Liu, Hong Yan Zeng, Ping He, Deng Hong Peng, Bi Foua Claude Alain Gohi, Bin Fan, Chao Yu, Yu Qin Li
Abstract: Candida rugosa Lipase was immobilized on the activated nylon-6 membrane using 0.5% glutaraldehyde as cross-linking agent. The immobilized lipase had an improved temperature and pH stability and exhibited good reusability. The adsorption process followed pseudo-second order rate equation and the biosorption isotherms correlated well with the Langmuir isotherm model. Negative ΔG indicated the adsorption process was spontaneous and the positive of ΔH indicated that the adsorption was endothermic.
Authors: Irene Guiamatsia, Giang Dinh Nguyen
Abstract: Failure develops and propagates through a structure via a complex sequence of competing micro-mechanisms occurring simultaneously. While the active mechanism of surface debonding is the source of loss of stiffness and cohesion, friction between cracked surfaces, upon their closure, acts as a passive dissipation mechanism behind the quasi-brittleness and hence can increase the toughness of the material under favorable loading conditions. In order to numerically study damage propagation, the constitutive response must be able to faithfully capture, both qualitatively and quantitatively, one of the signature characteristic of failure: the energy dissipation. In this paper, we present an interface decohesive model for discrete fracture that is able to capture the apparent enhancement of interfacial properties that is observed when transverse compressive loads are applied. The model allows to seamlessly account for the additional frictional dissipation that occurs when the loading regime involves transverse compression, whether during debonding or after full delamination. This constitutive model is then used to successfully predict the response of realistic engineering structures under generalized loading conditions as demonstrated with the numerical simulation of a fiber push-out test.
Authors: Qi Lu, Wei Xu, Sybrand van der Zwaag
Abstract: This work presents an artificial intelligence based design of a series of novel advanced high performance steels for ambient and high temperature applications, following the principle of the materials genome initiative, using an integrated thermodynamics/kinetics based model in combination with a genetic algorithm optimization routine. Novel steel compositions and associated key heat treatment parameters are designed both for applications at the room temperature (ultra-high strength maraging stainless steel) and at high temperatures (ferritic, martensitic and austenitic creep resistant steels). The strength of existing high end alloys of aforementioned four types are calculated according to the corresponding design criteria. The model validation studies suggest that the newly designed alloys have great potential in outperforming existing grades.
Authors: George Kaptay
Abstract: In solidification experiments of binary eutectic alloys, the eutectic spacing and undercooling are measured as function of the solidification rate. A new theoretical relationship is derived herewith between the Gibbs-Thomson coefficient and the above mentioned values for both lamellar and rod type eutectics. This new equation allows the estimation of the interfacial energy between eutectic solid phases. For the Sn/Pb eutectics the value of about 0.15 N/m is found in this paper using experimental literature data on eutectic solidification experiments. This is consistent with an earlier value obtained by a more complex experimental method of Gündüz and Hunt.
Authors: Chun Long Li, Wei Chen, Zheng Yang Li, Feng Lan Wei
Abstract: In this essay, the charactristc index of the humidity controlling material is breifly illuminated, based on which, an observing experiment in a small enclosed box is made. According to the experimental phenomenon and the basic principles of the thermodynamics, the formulation of the humidity parameter in a closed space of greenhouse is derived, from the angle of two-phase equilibrium. We assert that the purpose of using B,the charateristic parameter, is to ensure that the temperature of the subjest is zero. So when the temperature is not zero, using this parameter will cause error. Since the imperfection of B, it is necessary to use another parameter, BT, which is derived according to the temperature of the subject and proved more reasonable, to reply the former one. Both parameters can reflect the combination of the material and the moisture, which relate to the binding energy. The humidity controlling character proves better, if the binding energy becomes closer to that of two pure water molecules.
Authors: Xing Xu, Na Hu, Wei Qin Ying
Abstract: There are many similarities between the intelligence algorithms and the Statistical Physics and Thermodynamics in many aspects, such as the research object, tasks and methods. Firstly, this paper presents the hybrid intelligence algorithms improved by Thermodynamics. Then the theory analysis of intelligence algorithms by Thermodynamics is presented. Finally, a new research direction, that is the novel intelligence algorithm based on statistical physics and thermodynamics, is proposed for the future.
Authors: In Gee Kim, Gul Rahman, Jae Hoon Jang, You Young Song, Seung Woo Seo, H.K.D.H. Bhadeshia, A.J. Freeman, G.B. Olson
Abstract: The formation enthalpy of a series of Fe-C carbides has been estimated using a first-principles approach. The Fe to C ratio dependence of the formation enthalpy is reasonable, but it is revealed that - and -carbides require an extraordinary environment to be able to form. Furthermore, an addition of substitutional solutes other than Fe and C should promote other carbides with different crystal structures. The analysis suggests further studies to discover the critical concentrations of alloying which stimulate the other carbides to become more stable.
Authors: Xiao Hong Chen, Su Su Wang
Abstract: In this paper, a thermodynamic approach is presented to model coupled fluid transport, heat transfer, long-term deformation and damage in polymeric materials. The well-known Gibbs free energy is expressed as a functional of stress, temperature and fluid concentration with damage being introduced as an internal state variable. Constitutive equations for nonlinear viscoelastic materials in hygrothermal environments are derived in memory functional forms. The kinetics of damage evolution induced by stress, temperature and fluid is described by a damage function with thermodynamic driving force. Governing equations for mass and heat transfer are obtained from transport laws relating fluid and heat fluxes to gradients of chemical potential difference and temperature. A superposition principle of time, temperature, fluid concentration, stress, and aging is proposed so that long-term property functions may be derived from momentary master curves by horizontal and vertical shifting. The approach provides a theoretical framework for evaluating longterm behavior of polymeric materials in hygrothermal environments from short-term experiments.
Authors: Katsunari Oikawa, Hajime Mitsui, Kiyohito Ishida
Abstract: A database for thermodynamic information of sulfides and carbo-sulfide in steels has been developed, where the thermodynamic properties of the relevant constituting sub-system of the complex system have been assessed by the CALPHAD (Calculation of Phase Diagrams) approach. The utility of this database is demonstrated in examples of phase diagram calculations of low carbon steels and stainless steels. The calculated results are in good agreement with experimental data. The developed thermodynamic database would be useful in predicting the formation of sulfides and carbo-sulfides in the commercial steels.
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