Values Of Thermodynamic Parameters Research Articles

Kinetics and mechanism of radium-isotopes dissolution in TENORM scale waste associated with petroleum production using certain organic carbon source: lactic acid solution-case study.

The present study is conducted to explore the dissolution as inferred from the kinetic mechanism for radium-isotopes (228Ra, 226Ra, and 224Ra) in the TENORM scale waste deposited in oilfield pipes and equipment, Gulf of Suez, Egypt. The main efficiency factors for Ra2+-compound dissolution by lactic acid (LA) solution, e.g., reactive organic carbon (i.e., electron-donor source), have been investigated, and optimum chemical conditions have been determined. The obtained data were also employed to predict the leaching kinetics and mechanism of the Ra2+-isotopes removal by three shrinking core models (SCM, liquid film process-chemical controlled process-diffusion controlled process) and Arrhenius model. The maximum leaching percentage of Ra2+-isotopes reached to 55-60% at the optimal leaching conditions (0.3M LA, 5h, 25°C, ϕ < 1mm, S/L ratio 10/50gmL-1). The Ra-isotopes removal proceeds kinetically by diffusion-controlled process. Activation energy (Ea) of the leaching process was 10.51kJmol-1. This value conforms that the leaching process for removal of Ra2+-isotopes in the TENORM scale waste by LA solution is controlled by a diffusion process. Values of thermodynamic parameters (∆Go,∆Ho,∆So) were determined and indicate that dissolution of Ra2+-isotopes in the studied waste is non-spontaneous and temperature dependent. Moreover, the leaching mechanism may be attributed to the dissolution of soluble exchangeable and acidic species of Ra2+-species and/or these due conversions of insoluble Ra-sulfate to more soluble Ra-sulfide and/or Ra-hydrogen sulfide by LA solutions.

Biosorptive Detoxification of Cosmos Red Dye by Raphinus Sativus Leaves and Citrus sinensis Peels from Water in Cost Efective and Ecofriendly Way

The purpose of this study was batch scale elimination of Cosmos Red dye from aqueous medium by low cost and environmentally friendly adsorbents. To study the dye removing capacity, leaves of Raphinus sativus (radish) and peels of Citrus sinensis (orange) were utilized. Two adsorption isotherms were studied to explain adsorption equilibrium. The Langmuir isotherm is compatible to adsorption data. Best adsorption capacities for Raphinus sativus and Citrus sinensis were: 3.437 mg/g and 5.844 mg/g correspondingly. Citrus sinensis peels showed more adsorption. The negative values of thermodynamic parameters ∆Go for both adsorbents have shown the feasibility of this process. The results had shown that for removal of Cosmos Red dye, Citrus sinensis (orange) peels are more efficient adsorbent as compared to Raphinus sativus leaves.

Controlled preparation of cerium oxide loaded slag-based geopolymer microspheres (CeO2@SGMs) for the adsorptive removal and solidification of F− from acidic waste-water

A new cerium oxide loaded slag-based geopolymer microspheres (CeO2@SGMs) was prepared by a two-step i.e. dispersion-suspension-solidification and in-situ co-precipitation method. The optimal parameters for the preparation of 0.02CeO2@SGMs were slag (30 g), 1.7 M water glass (12.86 g), water (8 g) and 0.02 mol/L of Ce4+. 0.02CeO2@SGMs was characterized by SEM, XRD, BET, EDX, FTIR, XPS and PSD techniques. The leaching concentration of Ca2+ (95.65 mg/L) was only 1/5 of the SGMs at pH 2 after the modification of CeO2. Adsorption data fitted well with Freundlich isotherm model suggesting multilayer adsorption mechanism with a maximum adsorption capacity for F− by 0.02CeO2@SGMs of 121.77 mg/g at 298 K. The negative values of thermodynamic parameters (ΔH0 and ΔS0) indicated the exothermic nature of the adsorption process with reduced chaos of the whole system. 0.02CeO2@SGMs exhibited excellent dynamic adsorption performance at 4 mL/min F− solution flow rate. The influence of various co-existing anions on adsorption of F− over 0.02CeO2@SGMs followed an order of: Cl− ≈ NO3− < SO42− << PO43−. Attributed to the facile preparation process, cost-effectiveness and environmental friendliness, the newly designed 0.02CeO2@SGMs can be deemed of promising industrial applications for the abatement of F− from wastewater.

Phosphate sequestration and recovery from eutrophication water by in situ magnesium phosphate formation

Abstract Phosphate removal from eutrophic lakes has caused wide concern in the world, while an effective process is still lacking. A novel synthetic magnesium carbonate with spherical flower-like structure (MCSF) was prepared. Its performance for phosphorus adsorption from a eutrophic lake by in situ magnesium phosphate formation was tested and characterized. The effect of initial phosphorus concentration, adsorption time, adsorption dose, temperature, ionic strength and pH on phosphorus adsorption by MCSF was investigated. Results showed that higher initial phosphorus concentration and longer adsorbing time could improve the adsorption capacity. The maximum sorption capacity was 143.27 mg/g under initial pH value 7.0. The phosphate adsorption process was fitted with the Langmuir isotherm model and pseudo-second-order model. Thermodynamic parameter values revealed that the sorption process at 298–318 K was spontaneous and endothermic. The X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS) characterization of MCSF revealed that electrostatic attraction and chemical conversion were the major contributors for phosphate adsorption. MCSF releases magnesium ions from its surface and rapidly combines with phosphate to form insoluble magnesium phosphate precipitate. The prepared MCSF has the potential to be used for the restoration of eutrophic lakes by removing phosphate with higher adsorption capacity.

The inhibition action of some organic polymers on the corrosion carbon steel in acidic media

Corrosion inhibition performance of three sodium polyacrylates polymers was analyzed for carbon steel type OLC 45 in 0.5 M H2SO4 solution. Effectiveness of this polymers were investigated by potentiostatic and potentiodynamic polarization methods, electrochemical impedance spectroscopy (EIS), Fourier transform infrared (FT-IR) spectroscopy, scanning electron microscopy (SEM) and metallurgical microscopy techniques. The polymers involved in this study are three sodium polyacrylates hydrophobically modified with linear and cyclododecyl and, respectively, dihexyl chain (NaPADD, NaPACDD and NaPADH). We assume that, these polymers prevent corrosion of metal electrodes by a protective process can be due to either the adsorption of inhibitor molecules building a protective film or achievement an insoluble complex. Results showed that these polymers accomplished a considerable inhibiting action on OLC 45 corrosion and act that a mixed corrosion inhibitors and it could be proved by the effects of polymers on the electrochemical properties of metal electrodes. The adsorption of the polymers on the electrodes surface obeys to the Langmuir isotherm model. The temperature influence on the corrosion behavior of the metal electrodes in 0.5M H2SO4 with and without the inhibitor at 800 ppm was analyzed in the temperature domain from 293 to 333 K. The negative value of thermodynamic parameter like Gibbs free energy of adsorption shows the spontaneity of adsorption process. The characterization by FT-IR and SEM confirms the adsorption of inhibitors and the formation of corrosion products on the working electrode surface. EIS and potentiodynamic polarization data were indicative its corrosion protection ability. The best inhibition of 97% gets at an inhibitor concentration of 800 ppm for NaPACDD.

Anisotropy of field dependent penetration depth and the Sommerfeld coefficient in the pnictide superconductor

The modified phenomenological Ginzburg-Landau (MPGL) theory used to observe the anisotropy of the penetration depth as well as the Sommerfeld coefficient in the pnictide superconductor of the composition Ba0.6K0.4Fe2As2. The values of such thermodynamic parameters have been theoretically calculated and presented in this context. The qualitative, as well as quantitative results of such anisotropies indicate the successful accomplishment of this theory to the superconducting system of Ba1-xKxFe2As2composition.

Biomolecular interactions and binding dynamics of tyrosine kinase inhibitor erdafitinib, with human serum albumin

Erdafitinib is an approved tyrosine kinase inhibitor that inhibits fibroblast growth factor receptor. It has been described as one of the potent anti-tumor drugs especially for the treatment of urothelial carcinoma. In this study, we have investigated the binding dynamics of erdafitinib with human serum albumin (HSA) using multiple spectroscopic techniques. The outcome of the results suggests the occurrence of static quenching during the interaction of HSA with erdafitinib which leads to the formation of non-fluorescent HSA-erdafitinib ground state complex. Formation of HSA-erdafitinib complex was also confirmed from the findings of absorption spectral analysis. The changes in microenvironment around hydrophobic domains (especially tryptophan and tyrosine) were deciphered from fluorescence spectroscopy which was further confirmed by synchronous spectral analysis. In order to gain insight into the binding site of erdafitinib in HSA, molecular docking combined with competitive displacement assay was performed. The modified form of Stern Volmer equation was used to estimate various binding parameters including number of binding sites. The findings are indicative of a single binding site (n = 1) with binding constant in the order of 104. The negative values of thermodynamic parameters like ΔG, ΔH and ΔS were suggestive of the binding reaction being spontaneous and exothermic, while the hydrogen bonds and Van der Waals interactions being the major forces present between HSA and erdafitinib. Circular dichroism spectral analysis revealed the alterations in the conformation of HSA structure and reduction in its α-helical content. Communicated by Ramaswamy H. Sarma

Inhibition effect of Cynara cardunculus leaf extract on corrosion of St37 steel immersed in seawater with and without bleach solution

The inhibition performance of an aqueous extract of Cynara cardunculus leaves on the corrosion of St37 steel immersed in seawater and seawater with bleach was investigated using weight loss measurements, electrochemical methods, and surface characterization techniques. It was found that the extract components acted primarily as a mixed-type inhibitor, and inhibition efficiency increased with increasing inhibitor concentration. Electrochemical impedance spectroscopy (EIS) and dynamic electrochemical impedance spectroscopy (DEIS) confirmed the formation of a protective layer on the metallic surface in both solutions. The adsorption of inhibiting molecules conformed to the Langmuir isotherm model. The thermodynamic parameter values indicated that chemisorption constituted the major contribution to the adsorption process. This result was corroborated by scanning electron microscopy (SEM) and energy-dispersive X-ray (EDX) analyses. The significant inhibition effect can be related to the large amount of phenolic compounds in the CC aqueous extract as revealed by the Fourier-transform infrared (FTIR) spectrum.

Adsorption Characteristics of Allura Red AC onto Sawdust and Hexadecylpyridinium Bromide-Treated Sawdust in Aqueous Solution.

The Allura red AC (ARAC) dye adsorption onto natural sawdust (NSD) and hexadecylpyridinium bromide-treated sawdust (MSD) was investigated in aqueous solution as a function of contact time, solution pH, particle size, adsorbent dosage, dye concentration, temperature, and ionic strength. The adsorbents were characterized by Fourier transform infrared spectroscopy and X-ray diffraction crystallography. The dye adsorption onto both adsorbents was confirmed by field emission scanning electron microscopy and energy-dispersive X-ray spectroscopy. The maximum dye adsorption was found within 120 min at pH 2.0 for NSD and pH 3.0 for MSD, respectively, with a particle size of 0–75 μm and an adsorbent dosage of 0.07 g/50 mL ARAC dye solution (50 μmol/L). The batch adsorption kinetic data were followed by the pseudo-second-order kinetic model rather than the pseudo-first-order and Elovich kinetic models. Equilibrium adsorption isotherms were explained by the Langmuir isotherm model, and the maximum extent of adsorption was found to be 52.14 μmol/g for NSD and 151.88 μmol/g for MSD at 55 °C. The values of activation energy (Ea) and thermodynamic parameters (ΔG⧧, ΔH⧧, ΔS⧧, ΔG°, ΔH° and ΔS°) proved that the ARAC dye adsorption onto both adsorbents NSD and MSD is a spontaneous-endothermic physisorption process. ARAC (98–99%) was released from dye-loaded adsorbents in aqueous solution (pH ≥ 12) within 120 min. The adsorbents NSD and MSD were reused for a second time without significant loss of their adsorption efficiency.

Experimental investigation on thermodynamic properties and crystal structure of La 0.78Ba0.22MnO3 compounds

In this work, powder [Formula: see text] samples (purity of 99.99 % and density of [Formula: see text] were used. The crystal structure of [Formula: see text] compound was studied by X-ray diffraction method. It was determined that the crystal structure of this compound consists of two phases at room-temperature and under normal condition. These structure phases correspond to the cubic symmetry with Pm-3m space group and rhombohedral symmetry with the R-3c space group. Thermo Gravimetric (TG), Differential Scanning Calorimetry (DSC), Differential Thermo Gravimetric (DTG) and Differential Thermal Analysis (DTA) of [Formula: see text] compound were carried out in a high-temperature range of [Formula: see text]. It has been found that at high-temperatures, two-phase transition occurs in this compound. The value of thermodynamic parameters was found out for each phase transit.

Potentiality of uranium recovery from G.Gattar leach liquor using Duolite ES-467 chelating resin: Kinetic, thermodynamic and isotherm features

ABSTRACTIn the present study, adsorption of uranium from sulphate solutions was performed using Duolite ES-467 aminophosphonic acid chelating resin. Batch adsorption experiments were applied to assess the optimum parameters at pH3, 0.1 g resin dose, and 200 mg/L initial U(VI) concentration, for 90 min contact time at room temperature. The maximum sorption capacity was 75 mg/g at 25°C.From kinetic parameters, it was found that U(VI) adsorption followed pseudo-first-order kinetics. Besides, the equilibrium data fitted well with the Langmuir isotherm model. The values of thermodynamic parameters (ΔH, ΔS, and ΔG) indicated that the uranium adsorption processes could be considered endothermic, randomness, and spontaneous using Duolite ES-467 resin. U(VI) waswholly eluted from the loaded Duolite ES-467 resin using 0.5 M HNO3. Finally, the optimised factors were applied for U(VI) recovery from G. Gattar for leach liquor to produce a uranium concentrate (Na2U2O7) with 70.45% U(VI) content.

Improvement of the sorption behavior of aluminum silicate composite toward 134Cs and 60Co radionuclides by non-living biomass of Chlorella vulgaris.

Cesium and cobalt radioactive isotopes (134Cs and 60Co) are dangerous to human health due to their long half-life about 2.1 and 5.3year, respectively. Developing a new composite used as an efficient sorbent for these is an urgent requirement for radioactive waste management. Herein, preparation of different materials such as aluminum silicate (AS), cultured of Chlorella vulgaris (NCV) alga, and aluminum silicate/Chlorella vulgaris (AS/NCV) composite 3:1 were prepared by wet chemical technique and used to remove the 134Cs and 60Co radionuclides. Different analytical techniques were used to characterize the prepared sorbents as SEM, TEM, XRD, BET, TGA/DTA, FTIR particle size analyzer, and pore size distribution. The factors affecting the sorption process as pH, temperature, contact time, and weight of adsorbent were studied. The sorption process was found to follow a pseudo-second-order mechanism. The monolayer capacity for 134Cs radionuclide onto the aluminum silicate, non-living Chlorella vulgaris biomass, and aluminum silicate/Chlorella vulgaris composites are 66.67, 83.54, and 90.11mg/g, respectively, and for 60Co radionuclide are 59.31, 91.99, and 99.24mg/g, respectively. The values of thermodynamic parameters indicate that the sorption process is endothermic and spontaneous.

Kinetics of diclofenac adsorption from aqueous solution on commercial activated carbon

This paper studies the possibility of using activated carbon as an adsorbent for diclofenac (DFC) from aqueous medium. Batch sorption experiments were performed, and the influence of different parameters was studied: adsorbent dose, contact time and temperature. The experimentally obtained results were fitted according to two linear theoretical models of isotherms: Freundlich and Langmuir and according to two different kinetic models: pseudo-first and pseudo-second order. The optimal adsorption parameters were found to be: dose of adsorbent 0,5 g; contact time 60 minutes and temperature 20ºC, and the removal efficiency of diclofenac at these parameters was 92.8%.The results showed that the adsorption process follows a pseudo-second order kinetics and better matches the Freundlich isotherm model. The values of thermodynamic parameters indicate that adsorption process is spontaneous and exothermic. Based on the obtained data, it can be concluded that commercial activated carbon is an effective adsorbent for diclofenac from aqueous solution.

Optimization and genetic programming modeling of humic acid adsorption onto prepared activated carbon and modified by multi-wall carbon nanotubes

Milk vetch species (MV) as activated carbon (AC) precursors were prepared and modified by multi-wall carbon nanotubes (CNTs) in order to remove humic acid (HA) removal. Scanning electron microscopy (SEM), diffuse reflectance infrared Fourier transform spectroscopy (FTIR) and Brunauer Emmett Teller (BET) techniques were applied to characterized MVAC/CNTs. The HA adsorption presented the highest value (22.57 mg/g) at pH 3, while the equilibrium state was reached after 30 min. By increasing the adsorbent’s dosage (0.4–0.5 g/L), the removal efficiency was also improved from 90.3 to 97.6%. The kinetics of adsorption were fitted to the pseudo-second-order model (R2 = 0.9991). The Langmuir isotherm model was well fitted to the equilibrium data revealing monolayer adsorption model of HA onto the MVAC/CNTs with the maximum capacity of 73.29 mg/g (R2 = 0.9967). The obtained values of thermodynamic parameters indicated that the HA adsorption was spontaneous, endothermic and physical in nature. Also, genetic programming was used to obtain an appropriate equation revealing the relationship between the variables. The results showed that the introduced equation can successfully predict the HA removal. All experimental results suggested that MVAC/CNTs are promising adsorbents for the contaminated (with HA) water.

Green fabrication of ZnO nanoparticles using Eucalyptus spp. leaves extract and their application in wastewater remediation

The present study explored removal of carcinogenic cationic and anionic dyes from aqueous medium using green fabricated zinc oxide nanoparticles (ZnO-NPs). The ZnO-NPs were synthesized employing biogenic green reduction and precipitation approach. The characterization of ZnO NPs was done using various techniques such as FESEM, XRD, BET, TGA, HRTEM, EDX, and FTIR. All experiments were conducted in batch mode. Maximum removal was achieved at pH 6.0 and pH 8.0 for Congo Red (CR) and Malachite Green (MG) dyes respectively. Dye adsorption process showed better fit with Langmuir and Temkin isotherm models for CR dye and MG dye respectively. Maximum adsorption capacity of ZnO NPs was 48.3 mg/g for CR dye and 169.5 mg/g for MG dye. The dye adsorption followed pseudo-second order model and values of thermodynamic parameters confirmed that the adsorption process was spontaneous and favourable. Reusability efficiency of the nanoparticle was explored using ethanol and water and based on results it was inferred that ZnO-NPs can be reused for dye removal. Effect of salinity on the removal of CR and MG dyes was also explored and found that presence of salinity in aqueous medium have adverse impact on the dye removal efficiency of ZnO-NPs.

Experimental study and quantum-chemical simulation of piroxicam adsorption on the coal sorbent from walnut shells

The aim of this work was to study the sorption of piroxicam on the surface of activated carbon obtained by heat treatment from walnut shells. The objects of study are piroxicam (a) and model clusters of the sorbent. The quantitative determination and study of the sorbability of piroxicam is based on photometric recording of spectra at λ 400 nm. The most complete sorption of piroxicam occurs at pH 6,8–7,3, where the maximum difference in the optical density of the solutions was observed before and after sorption, which indicates the formation of a stable state of piroxicam. The results obtained from three series before and after sorption were subjected to statistical processing. The dependences “sorption – equilibrium concentration” presented at various temperatures made it possible to attribute the obtained curves to the Langmuir solution. Based on the obtained thermodynamic indicators, the following conclusions can be made: the reaction proceeds spontaneously, exothermally. Saturation of the surface of activated carbon with a monomolecular layer of piroxicam does not depend much on temperature changes, which is confirmed by close values of thermodynamic parameters at three temperatures. Quantum chemical calculations of the starting materials and model adsorption complexes in the “piroxicam – activated carbon surface” system were performed using the GAMESS US and MOPAC software. As a result of the work done, it was found that activated carbon obtained by heat treatment of walnut shells is a good and quite promising material for concentrating piroxicam and other drugs with the aim of subsequent determination from water and various biological environments.

Novel red mud/polyacrylic composites synthesized from red mud and its performance on cadmium removal from aqueous solution

AbstractBACKGROUNDRed mud (RM) is a solid waste generated by the aluminum industry and has demonstrated promising physical adsorption properties for cadmium (Cd) due to its relatively large surface area. To improve the chemisorption performance of RM for Cd(II) ions, a new method utilizing in situ graft polymerization in a reversed‐phase suspension system is proposed, and red mud/polyacrylic acid (RM/PAA) composites were synthesized for the first time.RESULTSThe RM/PAA composites were used to adsorb Cd(II) ions from aqueous solutions. Batch equilibrium measurements of RM/PAA were carried out to optimize the parameters. The characteristics were analyzed by scanning electron microscopy, the Brunauer–Emmett–Teller method, X‐ray diffraction, Fourier transform infrared and X‐ray photon spectroscopy. The maximum adsorption capacity of RM/PAA reached 96.15 mg g−1, which was much higher than that of the RM (21.70). The Cd(II) adsorption rate increased with increasing solution temperature and followed pseudo‐second‐order kinetics. The experimental data fitted well with the Langmuir isotherm model, indicating that the adsorption followed the monolayer adsorption model. The thermodynamic parameter values suggested that endothermic and spontaneous adsorption occurred. The surface of RM/PAA possesses abundant oxygen‐containing functional groups, and because the specific surface area of the RM/PAA decreased and the amount of adsorption increased compared with those of RM, the surface groups contribute more to Cd(II) retention. Physical adsorption, ion exchange and chelation were possibly the predominant adsorption mechanisms.CONCLUSIONThus, the RM/PAA composites produced from RM are considered effective and low‐cost adsorbents for Cd(II) removal from aqueous solutions. This study is of great significance for waste utilization and environmental protection. © 2019 Society of Chemical Industry

Features of Determining Thermodynamic Parameters of Formation of Nucleic Acid Complexes Using Thermal Denaturation with Fluorimetric Signal Detection

In this work, the possibility of precise physicochemical analysis of formation of nucleic acid complexes has been demonstrated using thermal cyclers with fluorescence signal detection. Individual features of heating blocks of various thermal cyclers have been identified. A nonlinear correlation between fluorescence signal intensity and concentration of fluorescent dyes (5,6)-carboxyfluorescein and Rhodamine B has been identified. Using UV and fluorescence melting, the comparison of melting curves at various concentration of full-complementary and mismatched (A/A and C/A) complexes has been conducted. The experimental values of thermodynamic parameters of complex formation for full-complementary and mismatched complexes have been obtained.

In-vitro Fluorescence Spectroscopic Analysis of the Interaction of Glimepiride with Bovine Serum Albumin (BSA)

Background: The significant study was made to investigate the interaction of an antidiabetic drug, glimepiride with bovine serum albumin (BSA) by fluorescence quenching method in two different temperatures (298K and 308K).&#x0D; Methods: The study was carried out through fluorescence spectroscopic analysis. Stern-Volmer equation determined the fluorescence quenching constant. The various thermodynamic parameters such as free energy (ΔG), enthalpy (ΔH), and entropy (ΔS) was found out by Van’t Hoff equation.&#x0D; Results: The data revealed that glimepiride interact with BSA and both tryptophan and tyrosine residues of BSA are responsible for interactions with glimepiride. BSA undergo static quenching in presence of glimepiride, a quencher. The hydrophobic forces participated in chief roles for BSA-glimepiride complexation and this was indicated by the values of thermodynamic parameters. The binding number (n) obtained was ≈1 pointed out that glimepiride and BSA has bound with 1:1 ratio.&#x0D; Conclusions: Through fluorescence spectroscopic technique we revealed the nature of interaction of glimepiride with BSA, quenching mechanism for the interaction and associated thermodynamic parameters.

Анализ расчетов идеального и реального циклов двигателя внутреннего сгорания

The purpose of this article is to study the thermodynamic efficiency of the real cycle of the internal combustion engine. There are various methods for calculating the values of the main thermodynamic parameters of the efficiency factor and average pressure in the nodal points. According to the known data, these results significantly differ from the real ones. The most rational assessment of engine performance is the one using the proven methods. Today there are enough assessment methods of internal combustion engine efficiency, the main ones are entropy and exergy methods. The object of research is the exergy method since it is more versatile. Consideration is given to a 4-stroke diesel engine V-84, which is widely used in military equipment. The ideal and real cycles of the internal combustion engine are calculated. Their input parameters are taken from tactical and technical characteristics of the engine V-84. The exergy method applied to estimate the efficiency of both cycles serves the basis for building entropy vs enthalpy graphs. The latter demonstrate that the maximum losses occur in the real cycle. The conducted calculations allowed to obtain the dependences of the object exergy (object efficiency) on the level of energy dissipation, enthalpy. A graph of exergy variations at cycle control points is obtained. It is proposed to carry on further studies where to assess the reduction of the object performance when in operation. This can be used in the development of the actual technical condition-based operation strategy. The study results are proposed to be used in the comparison of experimental data with reference ones. Moreover, it is possible to predict the changes in the performance level by a generalized criterion, which is the exergy of the working medium.