Electrochemical characterization and thermodynamic tendency of β-Lactoglobulin adsorption on 3D printed stainless steel

M.J.K Lodhi,K.M. Deen,Zia Ur Rahman,Ameeq Farooq,Waseem Haider 한국공업화학회 2018 Journal of Industrial and Engineering Chemistry Vol.65 No.-

The electrochemical behavior of 3D printed 316L stainless steel (3DPSS) was investigated in phosphate buffer saline (PBS), containing β-Lactoglobulin (BLG). The charge transfer resistance (Rct) was decreased from 629 to 40 k Ω cm2 with an increase in temperature from 293 to 323 K in BLG free electrolyte. At each temperature, the exponential decrease in the polarization resistance (Rp) of 3DPSS was a function of BLG concentration. The significant decrease in activation energy ‘Ea’ (∼15 kJ mol−1) upon adding 0.06 g/L BLG attributed to the charge transfer process involved in the adsorption process. The results were further used to quantify the thermodynamic parameters.

Vapor pressure and Flory-Huggins interaction parameters in binary polymeric solutions

Milad Asgarpour Khansary 한국화학공학회 2016 Korean Journal of Chemical Engineering Vol.33 No.4

This communication reports two unique relationships for (1) Flory-Huggins interaction parameter (χ) and (2) vapor pressure of solvent (P), which explicitly show their composition dependency. There is no empirical constant in the proposed relationships, and no trial and error and/or data-fitting optimization is required for determination and/ or correlation of vapor pressure and Flory-Huggins interaction parameter. A straightforward computational technique for implementation of models is provided. For a number of systems, the calculated data have been compared and evaluated against experimental ones and the reliability and accuracy of proposed relationships was assured. IARD (%) values on the order of 0.05 demonstrate the accuracy of the proposed method.

Dynamics of multilayered viscoelastic beams

H. Roy,J.K. Dutt,P.K. Datta 국제구조공학회 2009 Structural Engineering and Mechanics, An Int'l Jou Vol.33 No.4

Viscoelastic materials store as well as dissipate energy to the thermal domain under deformation. Two efficient modelling techniques reported in literature use coupled (thermo-mechanical) ATF (Augmenting Thermodynamic Fields) displacements and ADF (Anelastic Displacement Fields) displacements, to represent the constitutive relationship in time domain by using certain viscoelastic parameters. Viscoelastic parameters are first extracted from the storage modulus and loss factor normally reported in hand books with the help of Genetic Algorithm and then constitutive relationships are used to obtain the equations of motion of the continuum after discretizing it with finite beam elements. The equations of motion are solved to get the frequency response function and modal damping ratio. The process may be applied to study the dynamic behaviour of composite beams and rotors comprising of several viscoelastic layers. Dynamic behaviour of a composite beam, formed by concentric layers of steel and aluminium is studied as an example.

Dynamics of multilayered viscoelastic beams

Roy, H.,Dutt, J.K.,Datta, P.K. Techno-Press 2009 Structural Engineering and Mechanics, An Int'l Jou Vol.33 No.4

Viscoelastic materials store as well as dissipate energy to the thermal domain under deformation. Two efficient modelling techniques reported in literature use coupled (thermo-mechanical) ATF (Augmenting Thermodynamic Fields) displacements and ADF (Anelastic Displacement Fields) displacements, to represent the constitutive relationship in time domain by using certain viscoelastic parameters. Viscoelastic parameters are first extracted from the storage modulus and loss factor normally reported in hand books with the help of Genetic Algorithm and then constitutive relationships are used to obtain the equations of motion of the continuum after discretizing it with finite beam elements. The equations of motion are solved to get the frequency response function and modal damping ratio. The process may be applied to study the dynamic behaviour of composite beams and rotors comprising of several viscoelastic layers. Dynamic behaviour of a composite beam, formed by concentric layers of steel and aluminium is studied as an example.

Predictions of thermodynamic properties of pure fluids, refrigerants, and binary mixtures using modified Peng-Robinson equation of state

Pradnya Nirmala Prabhakar Ghoderao,Mohan Narayan,Vishwanath Haily Dalvi,변헌수 한국화학공학회 2022 Korean Journal of Chemical Engineering Vol.39 No.12

The Peng-Robinson (PR) EOS is a very successful two-parameter equation of state to estimate thermodynamicproperties of pure compounds as well as mixtures. The PR EOS has been modified and revised several ways toimprove estimates, and the most popular modification is for the attractive term through alpha function and temperaturedependent covolume parameter in the repulsive term. However, the unphysical, i.e., negative values of temperaturedependent co volume parameter at high temperature lead to undesirable results. We have addressed this issue inthe present work by incorporating a temperature dependent covolume parameter and yet physically consistent over alarge range of temperature. In the present work, the Modified-Peng-Robinson 2 (MPR2) equation of state is presentedby modifying the alpha function in attractive term and temperature dependent co-volume parameter in repulsive termof the PR EOS. The accuracy of MPR2 EOS is demonstrated by comparing results with the PR, HKM1, and MPR1equations of state. The thermodynamic properties, namely saturated vapor pressure and liquid density, enthalpy ofvaporization, compressed liquid densities in sub and supercritical region, heat capacities (isobaric and isochoric), andsound velocity of pure compounds, are predicted by MPR2 EOS which agrees very well with the experimental data. We have further studied 24 refrigerant properties like vapor and liquid densities. The work has also been extended tostudy the phase behavior of 26 binary mixtures using van der Waals single fluid mixing rules.

Thermotropic liquid crystalline 4-(Nonyloxy) benzoic acid: Phase transition temperatures, thermodynamic characterization, and separation of structural isomers

Isik Birol,Cakar Fatih,Cankurtaran Husnu,Cankurtaran Ozlem 한국화학공학회 2023 Korean Journal of Chemical Engineering Vol.40 No.11

The retention behavior of various organic probes on the 4-(Nonyloxy) benzoic acid liquid crystal, which is used as a stationary phase, was investigated using the inverse gas chromatography method at infinite dilution. The thermodynamic parameters including the Flory-Huggins parameter, equation-of-state interaction parameter, the mole fraction activity coefficient, the effective exchange energy parameter, and residual thermodynamic parameters were determined in the temperature range of 423.15-433.15 K by using the retention behavior of the probes on the liquid crystal. It was determined from the thermodynamic parameters that all probes were poor solvents for the liquid crystal. Besides, the results of the 4-(Nonyloxy) benzoic acid liquid crystal was compared with a liquid crystal in the literature, and the effect of the number of alkyl groups on the liquid crystals on the Flory-Huggins interaction parameter and isomer separation was evaluated.

Thermodynamic analysis of MauG, a diheme oxygenase

Kim, Han-bin,Shin, Sooim,Choi, Moonsung The Korean Society for Applied Biological Chemistr 2018 Applied Biological Chemistry (Appl Biol Chem) Vol.61 No.1

MauG is a unique c-type diheme oxygenase. One heme of MauG is five-coordinate and solvent accessible with His53 as axial ligand, while the other heme of MauG is six-coordinate with His205 and Tyr294. MauG catalyzes posttranslational modification including oxygen insertion, cross-linkage of two tryptophan and oxidation of quinol to quinone of precursor methylamine dehydrogenase (preMADH) to form mature tryptophan tryptophylquinone (TTQ) which is one of protein-derived cofactors. Longrange remote catalysis of substrate is possible without direct contact between hemes of MauG and its substrate, preMADH. Although catalytic properties and mechanisms of MauG have been well studied, temperature dependence of MauG has never been reported yet. Therefore, the objective of this study was to perform thermodynamic analysis of MauG. ${\Delta}H^{\circ}$ of $87.6{\pm}6.7kJ\;mol^{-1}$ and ${\Delta}S^{\circ}$ of $232{\pm}15.6J\;mol^{-1}\;K^{-1}$ were directly measured for oxidized MauG in this study. Those results provide fundamental information on controlling electron transfer rates for biosynthesis of TTQ in MADH and are used as a good thermodynamic example study for other diheme systems.

A review of molecular interactions in organic binary mixtures

Firdosa Nabi,Maqsood Ahmad Malik,Christopher Gunaseelan Jesudason,Shaeel Ahmed Al-Thabaiti 한국화학공학회 2014 Korean Journal of Chemical Engineering Vol.31 No.9

The intention of this review article is to review the knowledge about interactions in organic binary liquidmixtures. Molecular interactions in organic binary liquid mixtures are interesting due to their extensive use in manyfields of solution chemistry. The thermodynamics of component molecules present in various systems interacting areparticularly interesting because they display fantastic results. Studies of different organic liquid mixtures represent thedifferent modes of interactions prevailing in the component molecules. The number of parameters required describingthe properties of a given class of mixtures increases sharply with the number of segment types involved. In recent years,the theoretical and experimental investigations of interactions between unlike molecules have been conveniently carriedout using excess thermodynamic functions. The properties of liquid mixtures depend on the forces between moleculesand on the nature and volume of these molecules, and change with the composition of the mixtures. This change, inturn, is reflected in the thermodynamic properties of the mixtures. The influence of significant contributions of a chem-ical, physical and geometrical nature that change excess thermodynamic properties is considered and explained in detail.

Mn-Si 용탕내 Si의 열역학적 거동

백민규 ( Min Kyu Paek ),장정목 ( Jung Mock Jang ),강윤배 ( Youn Bae Kang ),박종진 ( Jong Jin Pak ) 대한금속재료학회 ( 구 대한금속학회 ) 2012 대한금속·재료학회지 Vol.50 No.2

Equilibria between Mn-Si melts and MnO-SiO2 slags were studied at 1673 K and 1773 K in MnO crucibles to accurately determine the thermodynamic property of the Mn-Si melts. The Unified Interaction Parameter Formalism (UIPF) was used to describe the thermodynamic property of the Mn-Si liquid. Using the UIPF, the experimental results obtained in the present study were thermodynamically analyzed to determine the activity coefficient of Si at infinite dilution and the 1st- and 2nd-order self-interaction parameters of Si in the Mn-Si melts.

탄소 포화 Mn 합금 용액내 C, Si 및 Fe 사이의 열역학적 상호작용

백민규 ( Min Kyu Paek ),이원규 ( Won Kyu Lee ),김길남 ( Ji Nan Jin ),장정목 ( Jung Mock Jang ),박종진 ( Jong Jin Pak ) 대한금속재료학회 ( 구 대한금속학회 ) 2012 대한금속·재료학회지 Vol.50 No.1

Thermodynamics of carbon in manganese alloy melts is important in manufacturing low carbon ferromanganese and silico-manganese alloys. In order to predict the carbon solubility in liquid Mn-Si-Fe-Csat alloys as a function of melt composition and temperature, thermodynamic interactions among carbon, silicon and iron in carbon saturated liquid manganese should be known. In the present study, the effects of silicon and iron on the carbon solubility in Mn-Si, Mn-Fe and Mn-Si-Fe melts were measured in the temperature range from 1673 to 1773 K. The carbon solubility decreases significantly as silicon and iron contents increase in liquid manganese alloy. The interaction parameters among carbon, silicon and iron in carbon saturated liquid manganese were determined from the carbon solubility data and the Lupis` relation for the interaction coefficient at constant activity.