INVALIDITY OF ISOTHERMAL ANALYSIS IN ESTIMATING THE THERMAL PERFORMANCE OF STIRLING ENGINE AND CRYOCOOLER

The Stirling engine is an external heat engine, which is considered as the best option for extracting work from concentrated solar power applications. The most prominent characteristics of the engine are low noise, vibration, and emissions besides reflexivity of usage with any kind of heat source such as solar, biomass, industrial heat, etc. In the present paper, the STE-1008 gamma-type Stirling engine had been analyzed by using an isothermal model to demonstrate the failure of the model in analyzing the STE-1008 considering it firstly as an engine and secondly as a cryocooler. The energy equation had been used to demonstrate the disability of the isothermal model in achieving a successful thermal analysis for engine performance. In addition, a MATLAB code had been developed to check the credibility of the isothermal model in the estimation of the engine thermal parameters. The findings of the isothermal analysis revealed that the heat exchangers are unnecessary. But, in reality; all the necessary heat transfer occur within the heat exchangers rather than in the working space boundaries. Therefore, that is invalid conclusion. However, Schmidt's theory is capable of capturing the essential engine features superbly. In particular, it is capable of capturing the fundamental interplay between the mechanically restricted movement of the engine components as well as the thermodynamic cycle which is obtained from this theory.

The β-lactam Ticarcillin is a Staphylococcus aureus UDP-N-acetylglucosamine 2-epimerase binder.

Infectious diseases account for 25% of the causes of death worldwide and this rate is expected to increase with the increasing rate of antibiotic resistance observed for many pathogens. Among the bacterial pathogens usually found in healthcare associated infections, Escherichia coli and Staphylococcus aureus are the most prevalent pathogens and, for the former, about 50% of the isolates are found to be methicillin resistant. Given the limited number of targets/pathways observed for the mechanism of action for the existing antibiotics, the discovery of newer targets and their evaluation becomes an urgent and necessary task. Here we describe the structure-based identification of ticarcillin as a weak binder of the UDP-N-acetylglucosamine 2-epimerase (MnaA) from S. aureus. After a docking-based screening of existing drugs, ticarcillin was identified as a ligand in isothermal analysis of differential scanning fluorimetry data. An equilibrium molecular dynamics simulation confirmed the docking binding mode as a stable pose, with large contributions to the binding energy coming from interactions between Arg206 and Arg207 and the carboxylate groups in ticarcillin.

Adsorption of Reactive Dye onto Uçá Crab Shell (Ucides cordatus): Scale-Up and Comparative Studies

The growing interest in using low-cost methods that use natural sources makes the study of adsorption processes increasingly frequent and common. Thus, the use of uçá crab shell (Ucides cordatus) in the adsorption of reactive dye (reactive blue 222) was studied in two systems (S1 and S2) in a finite bath, with a scale-up of 12 times and considering different forms of agitation. The biosorbent material was previously characterized from FTIR and EDX spectroscopies, SEM, physical adsorption of N2, and point of zero charge. The kinetic study allowed modeling the experimental data and defining the equilibrium time for the S1 system as 400 min, and the S2 system as 360 min. The equilibrium adsorption capacities are 3.623 mg·g−1 (S1) and 4.191 mg·g−1 (S2). The pseudo-second-order (PSO) model best described the experimental data. The favorable multilayer adsorption was confirmed for the isothermal analysis, and the Freundlich and Sips models represented the experimental data of S1 and S2, respectively. The results obtained are positive indications of the scale-up of the S2 system.

Anionic Methyl Orange Removal from Aqueous Solutions by Activated Carbon Reinforced Conducting Polyaniline as Adsorbent: Synthesis, Characterization, Adsorption Behavior, Regeneration and Kinetics Study

This work investigated the elimination of Methyl Orange (MO) using a new adsorbent prepared from Activated Carbon (AC) with polyaniline reinforced by a simple oxidation chemical method. The prepared materials were characterized using XRD, TGA, FTIR and nitrogen adsorption isotherms. Furthermore, PANI@CA highest specific surface area values (near 332 m2.g− 1) and total mesoporous volume (near 0.038 cm3.g− 1) displayed the better MO removal capacity (192.52 mg.g− 1 at 298 K and pH 6.0), which is outstandingly higher than that of PANI (46.82 mg.g− 1). Besides, the process's adsorption, kinetics, and isothermal analysis were examined using various variables such as pH, MO concentration and contact time. To pretend the adsorption kinetics, various kinetics models, the pseudo first- and pseudo second- orders, were exercised to the experimental results. The kinetic analysis revealed that the pseudo second order rate law performed better than the pseudo first order rate law in promoting the formation of the chemisorption phase. In the case of isothermal studies, an analysis of measured correlation coefficient (R2) values showed that the Langmuir model was a better match to experimental results than the Freundlich model. By regeneration experiments after five cycles, acceptable results were observed.

Numerical study of non-isothermal analysis of exiting sheet thickness in the calendering of micropolar-Casson fluid

This theoretical analysis reports on the non-isothermal calendering process of micropolar-Casson fluid and studies the viscoplastic and microrotation effects by utilizing the lubrication approximation (LAT). Exact dimensionless velocity and pressure gradient solutions are achieved. Then a numerical integration technique determined other mechanical quantities. Implementing the finite difference approximations resolved the energy expression. Graphs show how material parameters influence the pressure, pressure gradient, leave-off distance, temperature distribution, force, and power function. Temperature distribution increases with increased coupling number N and decreased Casson parameter [Formula: see text]. Force and power function increase with increased coupling number and decreased Casson parameter. Both Casson and coupling number control the pressure distribution and exiting sheet thickness.

Removal of methyl orange from from aqueous solutions using of PANI and PANI@Activated Carbon: Preparation, characterization, regeneration and comparative study

This work investigated the elimination of Methyl Orange (MO) using a new adsorbent prepared from Activated Carbon (AC) with polyaniline reinforced by a simple oxidation chemical method. The prepared materials were characterized using XRD, TGA, FTIR and nitrogen adsorption isotherms. Furthermore, PANI@CA highest specific surface area values (near 332 m2.g− 1) and total mesoporous volume (near 0.038 cm3.g− 1) displayed the better MO removal capacity (192.52 mg.g− 1 at 298 K and pH 6.0), which is outstandingly higher than that of PANI (46.82 mg.g− 1). Besides, the process's adsorption, kinetics, and isothermal analysis were examined using various variables such as pH, MO concentration and contact time. To pretend the adsorption kinetics, various kinetics models, the pseudo first- and pseudo second- orders, were exercised to the experimental results. The kinetic analysis revealed that the pseudo second order rate law performed better than the pseudo first order rate law in promoting the formation of the chemisorption phase. In the case of isothermal studies, an analysis of measured correlation coefficient (R2) values showed that the Langmuir model was a better match to experimental results than the Freundlich model. By regeneration experiments after five cycles, acceptable results were observed.

Ekstraksi Pektin dari Kulit Jeruk dan Kulit Pisang sebagai Biosorben pada Proses Adsorpsi Logam Berat Fe

One of the alternatives in the treatment of waste containing heavy metals is the use of natural materials as adsorbents, which is known as the biosorption process Pectin is one of the components found in plant cell wall compounds which contain many active groups that plays a key role in the biosorption process which can be used as biosorbents. In this research, the raw materials for pectin resources were orange peel and banana peel. The effectiveness of pectin for both ingredients will be analyzed on the basis of 2 variables, namely the length of contact time (60, 90, 120, and 150 minutes) and the mass of pectin used (20, 30, 40, and 50 mg). The pectin of orange and banana peel was proven by Fourier Transform Infrared (FTIR) analysis shown by C=O functional group of aldehyde and carboxylic acid compounds. The results of this study indicated that the optimum condition was 150 minutes contact with the addition of 50 mg pectin giving the best adsorption efficiency for orange peel pectin of 88,096% and banana peel pectin of 99,428%. From the isothermal analysis, the Langmuir and Freundlich isotherms can be applied to the adsorption of Fe metals using orange peel and banana peel pectin with a coefficient of determination of R2 ≥ 0.9.

Crystallization Mechanism and Photoluminescence Properties of CaF2–Al2O3–SiO2: Eu Glass-Ceramics Based on Nano-Scale Phase Separation Phenomenon

In this paper, CaF2–Al2O3–SiO2 glass containing nano-sized CaF2 crystals were fabricated using phase separation phenomenon and the effects of rare earth ion (Eu) addition on the optical properties were investigated. The formation conditions for nano-sized CaF2 crystal phase were confirmed using non-isothermal analysis and X-ray diffraction (XRD) measurement, while inhibiting anorthite or wollastonite crystal formation. The phase separation phenomenon in the mother glass and the nano-sized crystals generated by heat treatment were observed through the microstructure analysis using scanning electron microscopy (SEM). In addition, photoluminescence (PL) spectra and decay time analysis were performed to confirm the emission characteristics of Eu-doped glass-ceramics. The Eu-doped glass-ceramics produced in this study showed strong red light. The overall luminescence properties according to the heat treatment temperatures were found to shift from red to blue as indicated in the Commission International de l’Eclairage (CIE) color coordinate system.