Mixed Orientation Research Articles

Recrystallization kinetics and mechanical properties of cold-rolled and annealed CoCrFeNi multi-principal element alloy

The microstructure and mechanical properties have been investigated in a CoCrFeNi alloy cold-rolled to 80 % thickness reduction and subsequently annealed at 600 °C. It is observed that the as-rolled microstructure comprises extended regions of different dominant crystallographic orientations along with layers of mixed orientations. Shear bands are also present in this microstructure, with the susceptibility to shear banding varying significantly from region to region. Shear bands are most pronounced in extended regions containing narrow deformation twins, and are a crucial source of recrystallization nuclei. Analysis of the recrystallization kinetics indicates that the Avrami exponent is ∼1.6 for the first 30 min at 600 °C and that it decreases during further annealing. Tensile test data provide evidence that the sample annealed for 8 min, with a recrystallized fraction (fRX) of 13 % and an average recrystallized grain size of 0.8 μm, does not show any significant improvement in ductility compared to that in the as-rolled condition. However, the ductility is considerably improved in the sample annealed for 15 min, where fRX is 43 % and the average recrystallized grain size is 1.1 μm. This sample demonstrates a yield strength of 850 MPa and a total elongation to failure of 25 %. The data obtained in this work and in previous publications on partially recrystallized CoCrFeNi indicate that for samples annealed after 80–85 % deformation optimized combinations of strength and ductility are obtained when the recrystallized fraction is in the range 30 % < fRX ≤ 50 %.

Bimodal grain structure, phase transformation, and mechanical properties of a Mg-Gd-Y-Zn-Zr alloy during hot extrusion

In this study, we investigated the evolution of grain structures and second phases of a Mg-9.5Gd-4Y–2Zn-0.3Zr alloy during two-stage deformation that took place in the metal during hot extrusion, as well as their effects on its mechanical properties. We found that the alloy exhibited a bimodal grain structure consisting of equiaxed dynamic recrystallized (DRXed) grains and elongated unDRXed grains. As the extrusion process progressed, DRX occurred on a large scale, resulting in an increase in the proportion of DRXed grains from 17.8% to 93.2%, and a reduction in average grain size from 80.3 μm to 9.41 μm. The grain orientation also underwent a transition from a single orientation of an extrusion direction (ED) parallel to <0001> (i.e. ED//<0001>) to mixed orientations of ED//<01–10> and ED//<0001>. The primary mechanism of dynamic recrystallization (DRX) during extrusion involved particle-stimulated nucleation (PSN) accompanied by both continuous and discontinuous DRX. The Mg-9.5Gd-4Y–2Zn-0.3Zr alloy mainly contained intergranular 18R-long period stacking order (LPSO) phases and intragranular 14H-LPSO. As the extrusion process progressed, 18R-LPSO changed from blocky to lamellar to accommodate deformation, and β-Mg5(Gd,Y) phase particles dynamically precipitated along DRXed grain boundaries. The 14H-LPSO phase was found to be primarily distributed within coarse unDRXed grains. As deformation via extrusion progressed, the quantity of 14H-LPSO gradually decreased. Ultimately, with the gradual dissolution of Mg5(Gd,Y), 14H-LPSO reprecipitated within the recrystallized grain boundaries. As the extrusion process progressed, both the yield strength (YS) and elongation (EL) increased from 132.6 MPa to 287.6 MPa and from 10.8% to 15.5%, respectively. This was mainly attributed to the significant reduction in grain size and second phase size.

Drosophila anterior midgut internalization via collective epithelial-mesenchymal transition at the embryo surface and enclosure by surrounding tissues

Internal organ development requires cell internalization, which can occur individually or collectively. The best characterized mode of collective internalization is epithelial invagination. Alternate modes involving collective mesenchymal behaviours at the embryo surface have been documented, but their prevalence is unclear. The Drosophila embryo has been a major model for the study of epithelial invaginations. However, internalization of the Drosophila anterior midgut primordium is incompletely understood. Here, we report that an epithelial-mesenchymal transition (EMT) occurs across the internalizing primordium when it is still at the embryo surface. At the earliest internalization stage, the primordium displays less junctional DE-cadherin than surrounding tissues but still exhibits coordinated epithelial structure as it invaginates with the ventral furrow. This initial invagination is transient, and its loss correlates with the activation of an associated mitotic domain. Activation of a subsequent mitotic domain across the broader primordium results in cell divisions with mixed orientations that deposit some cells within the embryo. However, cell division is non-essential for primordium internalization. Post-mitotically, the surface primordium displays hallmarks of EMT: loss of adherens junctions, loss of epithelial cell polarity, and gain of cell protrusions. Primordium cells extend over each other as they internalize asynchronously as individuals or small groups, and the primordium becomes enclosed by the reorganizations of surrounding epithelial tissues. We propose that collective EMT at the embryo surface promotes anterior midgut internalization through both inwardly-directed divisions and movements of its cells, and that the latter process is facilitated by surrounding tissue remodeling.

An Ultramicroporous Zinc‐Based Zeolitic Imidazolate Framework‐8 for the Adsorption of CO2, CH4, CO, N2 and H2: A Combined Experimental and Theoretical Study

AbstractAn alternative synthesis route to obtain ultramicroporous zeolitic imidazolate framework‐8 (ZIF‐8) is reported that is rapid and does not require organic solvent or heating. The polyethylene glycol‐templated ZIF‐8 nanoparticles (&lt;50 nm size) exhibited a high BET (Brunauer, Emmett and Teller) surface area of 1853 m2/g, a total pore volume of 0.73 cm3/g, and 0.54 nm ultramicropores. A new approach is introduced here to better understand gas adsorption in porous metal organic frameworks (MOFs) that combines theoretical and experimental isotherm data obtained for five gases with statistical physics modelling. The multiscale analytical model reveals that the gas molecules, irrespective of their structure, adsorb in a mixed orientation at low temperature, and a parallel multi‐molecular orientation at higher temperature. The number of gas molecules adsorbed per site ranged from 0.83–2.2 while the number of adsorbent layers ranged between 1.4–5.6, depending on the gas and the temperature. The multilayer adsorption processes involved adsorption energies from 2.85 kJ/mol–9.77 kJ/mol for all gases, consistent with physisorption via van der Waals and London dispersion forces. The initial adsorption energies were higher and therefore stronger. A particularly high capacity for CO2 of 1088 mg(CO2)/g at 298 K was observed while H2 adsorption was only 9 mg(H2)/g. The other gases adsorbed at 145 mg/g–245 mg/g at 298 K. Thermodynamic functions that governed the adsorption process such as the internal energy, the enthalpy, and Gibbs free energy, are also reported, as well as the adsorption entropies, for the 5 gases.

Oxides Induced Preferential Growth of {110} Planes for Superior Performance Single-Crystal LiMn2O4 through Solid-State Process.

Polycrystalline lithium manganese oxide (LMO) is known to suffer from severe surface structure degradation and electrochemical polarization due to its mixed crystal plane orientations. A hexagonal prism single-crystal LMO (LMOS-HP), engineered through the SrO-induced preferential growth effect, features the most stable {111} top surfaces and the fastest Li+ diffusion {110} side surfaces, effectively addressing these challenges. Consequently, LMOS-HP exhibits superior electrochemical capability, with only 0.021% capacity fading per cycle after 500 cycles and achieves a discharge capacity of 81.9 mAh g-1 at 20C. This innovative design offers a promising approach for tuning surface crystal orientation to improve performance.

Numerical investigations of shock/boundary-layer interaction and control for Mach 2.5 flow in an axisymmetric inlet

The present work investigates the application of vortex generators for separation control in axisymmetric isolator flows. Reynolds-Averaged Navier-Stokes computations were performed to simulate a Mach 2.5 flow past a half-isolator geometry with a 20∘ axisymmteric compression ramp based on the experiments of Funderburk and Narayanaswamy at North Carolina State University. Single vortex generator and a vortex generator array placed upstream of the shock-induced separation region were investigated. Near wall streamlines, surface pressure contours and density contours on crosswise planes were compared with experiments for flow control using a single vortex generator. Results indicate that the present computations are able to capture the wake and shock structures, and also predict reduction in the streamwise extent of flow separation downstream of the device trailing edge. Finally, the effects of the shape/orientation (forward facing/backward facing) of a single vortex generator, and the design of an array of three vortex generators (with devices of similar and mixed orientations) on the flow separation were also investigated. Contours of near-surface streamwise velocity showed that device orientation had a strong effect on separation control, which is attributed to the differences in the primary streamwise vortices shed in the two cases. Further, the overall reduction in the footprint of separated flow was determined to be most with the use of an array of vortex generators with mixed orientations.

Experimental demonstration of tunable hybrid improper ferroelectricity in double-perovskite superlattice films

Hybrid improper ferroelectricity can effectively avoid the intrinsic chemical incompatibility of electronic mechanism for multiferroics. Perovskite superlattices, as theoretically proposed hybrid improper ferroelectrics with simple structure and high technological compatibility, are conducive to device integration and miniaturization, but the experimental realization remains elusive. Here, we report a strain-driven oxygen octahedral distortion strategy for hybrid improper ferroelectricity in La2NiMnO6/La2CoMnO6 double-perovskite superlattices. The epitaxial growth mode with mixed crystalline orientations maintains a large strain transfer distance more than 90 nm in the superlattice films with lattice mismatch less than 1%. Such epitaxial strain permits sustainable long-range modulation of oxygen octahedral rotation and tilting, thereby inducing and regulating hybrid improper ferroelectricity. A robust room-temperature ferroelectricity with remnant polarization of ~ 0.16 μC cm−2 and piezoelectric coefficient of 2.0 pm V−1 is obtained, and the density functional theory calculations and Landau-Ginsburg-Devonshire theory reveal the constitutive correlations between ferroelectricity, octahedral distortions, and strain. This work addresses the gap in experimental studies of hybrid improper ferroelectricity for perovskite superlattices and provides a promising research platform and idea for designing and exploring hybrid improper ferroelectricity.

Electro-optic effect in thin film strontium barium niobate (SBN) grown by RF magnetron sputtering on SrTiO3 substrates

Ferroelectric strontium barium niobate (SrxBa1−xNb2O6 or SBN) is a material with high electro-optic (EO) response. It is currently of interest in low voltage silicon-integrated photonics (SiPh). We have grown strongly textured SBN films with x = 0.65 by radio frequency sputtering on (100)-oriented SrTiO3 substrates where grains with mixed (310) and (001) out-of-plane orientation form. For these mixed orientation films, we observed a maximum effective EO coefficient of 230 pm/V using a transmission EO measurement geometry that is responsive only to the in-plane polarization component coming from the (310)-oriented grains. We also demonstrate that by growing SBN on TiO2-terminated SrTiO3 substrates, we can obtain predominantly (001)-oriented SBN films with out-of-plane polarization. Transmission EO measurements on such (001)-oriented films show a reduced effective Pockels coefficient of 88 pm/V, which is consistent with the overall ferroelectric polarization becoming out-of-plane. This work shows that controlling substrate termination is effective in controlling the grain orientation of SBN films grown on top and that one can readily integrate SBN films on SrTiO3-buffered Si for use in SiPh.

The Analysis of Conceptual Approaches to the Monitoring of Metacognitive Processes of Junior Schoolchildren

It is quite natural that in the educational process, within various academic subjects, the junior schoolchildren face a number of such difficulties as new types of tasks, mixed orientations in unfamiliar situations and so on. When we conduct research on the existing approaches, we come to the conclusion that it is necessary to manage metacognitive processes in order to ensure the cognitive level of junior schoolchildren. Those processes imply mechanisms in which the student has developed certain skills, as s/he consciously selects and performs actions that will lead to solving the assigned problems and identifying appropriate answers to the questions asked. In this article metacognitive processes are discussed not in the context of one academic subject, but in the context of all the academic subjects that are taught in elementary school. Due to metacognitive processes, the interdisciplinary ties within the subjects developing in the elementary school is also important. In addition, due to the metacognitive skills, the junior schoolchildren are able to apply the knowledge about one subject in the context of another subject. One of the components of managing the metacognitive processes of junior schoolchildren is the development of skills for the controversial understanding of new academic material, which excludes mechanical process. In the context of managing metacognitive processes, junior schoolchildren develop abilities with the help of which they not only learn academic material, but also create an environment for consolidating their knowledge.

Magnetic hybrid spheres of glauconite/calcium alginate interface for methylene blue adsorption: Synthesis, characterization, and novel physicochemical insights through theoretical treatment

Fe3O4 nanoparticles were embedded within a glauconite‑calcium alginate (G/CA) matrix to create magnetic hybrid spheres (MNPs-G/CA), with the aim of purifying water from methylene blue (MB) at temperatures of 25, 40, and 50 °C. MNPs-G/CA adsorbent was characterized using numerous techniques, including elemental mapping, zeta potential, FTIR, FESEM, XRD, EDX, and TEM. The greatest amount of the removed MB was achieved under definite conditions of solution pH 8.0, MNPs-G/CA mass (25 mg), interaction time (2 h), and 200 mg/L of MB concentration. The MB uptake process kinetic followed a pseudo-second-order equation (R2 > 0.99) at all tested temperatures. The equilibrium data were fitted to a statistical physics multilayer model in conjunction with the Langmuir and Freundlich equations. The steric n parameter reveals that MNPs-G/CA adsorbent possesses a mixed adsorption orientation (i.e., ranging from 0.69 to 0.93) across various temperatures. The amount of MNPs-G/CA active positions (the NM parameter) was progressively increased from 245 mg/g to 419 mg/g. The measured adsorption capacities (Qsat) ranged from 466.49 to 664.37 mg/g, and the removal of MB molecules was consistent with an endothermic interaction. The interface between the MNPs-G/CA-MB was principally dictated by electrostatic attractions, as evidenced by the values of adsorption energies (∆E), which varied from 16.75 to 21.52 kJ/mol. The regenerated MNPs-G/CA offered over 80 % of its adsorption strength after the fourth adsorption–desorption cycle. This study contributes to our understanding of the physicochemical parameters controlling the MB adsorption mechanism on multifunctional hybrid adsorbents, like the interface between glauconite, alginate, and MNPs.

Morphology-Controlled Ion Transport in Mixed-Orientation Polymers.

Advancing iontronics with precisely controlled ion transport is fundamentally important to bridge external organic electronics with the biosystem. This long-standing goal, however, is thus far limited by the trade-off between the active ion electromigration and idle diffusion leakage in the (semi)crystalline film. Here, we presented a mixed-orientation strategy by blending a conjugated polymer, allowing for simultaneously high ion electromigration efficiency and low leakage. Our studies revealed that edge-on aggregation with a significant percolative pathway exhibits much higher ion permeability than that of the face-on counterpart but encounters pronounced leakage diffusion. Through carefully engineering the mixed orientations, the polymer composite demonstrated an ideal switchable ion-transport behavior, achieving a remarkably high electromigration efficiency exceeding one quadrillion ions per milliliter per minute and negligible idle leakage. This proof of concept, validated by drug release in a skin-conformable organic electronic ion pump (OEIP), offers a rational approach for the development of multifunctional iontronic devices.

Control of the preferential orientation and properties of HiPIMS and DCMS deposited chromium coating based on bias voltage

This study investigates the effects of varying bias voltages on the crystallographic orientation and properties of DCMS + HiPIMS-deposited chromium coatings. Under bias voltages varying from 100 to 500 V, dense Cr coatings were obtained, and the deposition rate decreased by 13 %. The bias voltage significantly impacts the hardness, crystallographic orientation, electrical conductivity, and bonding strength of the coating. As the bias voltage increases, the hardness of the Cr coating gradually increases. The crystallographic orientation of the coating is governed collectively by surface energy, strain energy, and sputtering effects. The preferential crystallographic orientation of the Cr coating transitions from (222) to (110), subsequently changing to a mixed preferential crystallographic orientation of (110), (211), and (222). Under the combined influence of thermal effects and ion bombardment, a (110) preferential crystallographic orientation was obtained at a bias voltage of 300 V, featuring moderate hardness and optimal wear resistance. This study establishes that the electrical characteristics of the coatings have a significant correlation with bias voltage levels.

Effect of shape anisotropy on percolation of aligned and overlapping objects on lattices.

We investigate the percolation transition of aligned, overlapping, anisotropic shapes on lattices. Using the recently proposed lattice version of excluded volume theory, we show that shape-anisotropy leads to some intriguing consequences regarding the percolation behavior of anisotropic shapes. We consider a prototypical anisotropic shape-rectangle-on a square lattice and show that, for rectangles of width unity (sticks), the percolation threshold is a monotonically decreasing function of the stick length, whereas, for rectangles of width greater than two, it is a monotonically increasing function. Interestingly, for rectangles of width two, the percolation threshold is independent of its length. We show that this independence of threshold on the length of a side holds for d-dimensional hypercubiods as well as for specific integer values for the lengths of the remaining sides. The limiting case of the length of the rectangles going to infinity shows that the limiting threshold value is finite and depends upon the width of the rectangle. This "continuum" limit with the lattice spacing tending to zero only along a subset of the possible directions in d dimensions results in a "semicontinuum" percolation system. We show that similar results hold for other anisotropic shapes and lattices in different dimensions. The critical properties of the aligned and overlapping rectangles are evaluated using Monte Carlo simulations. We find that the threshold values given by the lattice-excluded volume theory are in good agreement with the simulation results, especially for larger rectangles. We verify the isotropy of the percolation threshold and also compare our results with models where rectangles of mixed orientation are allowed. Our simulation results show that alignment increases the percolation threshold. The calculation of critical exponents places the model in the standard percolation universality class. Our results show that shape anisotropy of the aligned, overlapping percolating units has a marked influence on the percolation properties, especially when a subset of the dimensions of the percolation units is made to diverge.

In situ neutron diffraction study and electron microscopy analysis of microstructure and texture evolution during annealing of rolled CoCrFeNi alloy doped with 1 at.%C

In situ neutron diffraction studies of changes in the dislocation density, volume fraction of carbides, and crystallographic texture have been performed during annealing of a cold-rolled multi-principal element CoCrFeNi alloy doped with 1 at.%C. In addition, microstructures of the as-rolled and several annealed samples of this alloy have been investigated using electron microscopy-based techniques. It is found that cold rolling to a thickness reduction of 74% results in a brass-type rolling texture with a spread of orientations between the Goss and brass components and with a pronounced 〈111〉//ND fiber. The deformed microstructure is characterized by a high density of dislocations and shows large variations in deformation structures in regions of different crystallographic orientations. In particular, bundles of deformation twins and high frequencies of shear bands are observed in regions having orientations along the 〈111〉//ND fiber. Annealing at 700 °C–1000 °C leads to recovery and recrystallization, during which shear bands and regions of mixed orientations act as preferential nucleation sites for recrystallized grains. Precipitation of M23C6 particles also takes place during annealing. The particles retard boundary migration, thus slowing down recrystallization and restricting grain growth. The average size of recrystallized grains does not exceed 5 μm even after annealing at 1000 °C for 60 min. While rolling textures are retained in some annealed samples, other samples demonstrate distinct recrystallization textures with new texture components. The results obtained in this work are compared with the literature data for several carbon-doped face-centered cubic multi-principal element alloys and for a carbon-free CoCrFeNi alloy.

N-Type ion gel gated vertical organic electrochemical transistors based on benzodifurandione-based Oligo(p-phenylene vinylene)s

Organic electrochemical transistors (OECTs) using aqueous gate dielectrics have garnered significant interest for bioelectronic applications. However, their viability for long-term use in neuromorphic computing and synaptic devices is limited due to their short-term functionality. In this study, we synthesize two benzodifurandione-based oligo (p-phenylene vinylene) polymers, BDOPV-TCNVT and ClBDOPV-TCNVT, and investigate their electrochemical transistor properties using quasi-solid-state ion gel-gated vertical OECTs (v-OECTs). Compared to BDOPV-TCNVT, the chlorinated ClBDOPV-TCNVT demonstrates lower frontier molecular orbitals and easier electrochemical doping. The higher volumetric capacitance of as-spun ClBDOPV-TCNVT (1.94 F cm−3) compared to as-spun BDOPV-TCNVT films (1.49 F cm−3) is mainly attributed to the easier ion infiltration resulting from its lower crystallinity with mixed chain orientation. The quasi-solid-state v-OECTs based on both polymers (as-spun) exhibit transconductance (gm) of 0.06–0.08 mS. Following thermal treatments, the gm gradually decreases for both polymers due to enhanced edge-on ordering with tight interchain packing, hindering ion penetration. Despite the poor electrochemical doping by quasi-solid-state ion gel gated dielectrics, the enlarged area and decreased channel length in v-OECTs (compared to parallel OECTs) can enhance the gm. Further optimization of v-OECTs requires tailored material designs specifically suited for efficient vertical charge transport together with ion infiltration.

Advanced analysis of the adsorption mechanism for sweet odorant on mouse and human olfactory receptors via statistical physics theory

In this work, the one layer statistical physics model (M1) was applied to more deeply comprehend the phenomenon of adsorption, which is putatively involved in the olfactory sensation of acetophenone (AP) on mouse and human olfactory receptors. On one hand, the proposed model was utilized to microscopically characterize the studied olfactory systems in order to obtain advanced stereographic and energetic information concerning the studied olfactory systems in terms of a molecular view point. Based on the values of the number of acetophenone molecules docked on mouse and human binding sites n, it was found that the studied sweet odorant was linked with a mixed orientation. Energetically speaking, the values of the molar adsorption energy ΔE1, which ranged from 11.81 to 17.67 kJ/mol for mouse olfactory receptors (Olfr62, Olfr1093, Olfr1094, Olfr895, and Olfr876) and from 14.66 to 20.58 kJ/mol for human olfactory receptors (OR2C1, OR1A1, and OR2J2), indicated that acetophenone molecules were exothermically physisorbed. The adsorption energy distributions relative to AP may also be estimated to understand the olfactory sense in the investigated olfactory systems via the calculation of olfactory bands (i. e., AED bands), which may be defined between 4.80 and 27 kJ/mol and between 5.50 and 27 kJ/mol for mouse and human olfactory receptors, respectively. On the other hand, M2 was used to determine three thermodynamic potentials (i.e., the internal energy, the Gibbs free energy, and the adsorption entropy), which macroscopically characterized the investigated olfactory systems via a detailed thermodynamic analysis of the different olfactory systems.

Implementation of different scanning strategy to improve the mechanical and wear properties of 15-5 PH stainless steel fabricated by laser-directed energy deposition

In this work, the effect of three different scan patterns (island scan pattern, island alternative scan pattern and cross-hatch pattern) on mechanical and wear properties is investigated for 15–5 Precipitation-hardened (PH) stainless steel by using laser-directed energy deposition (L-DED). Six rectangular blocks are deposited with constant laser power and scanning speed. Currently, studies on the control of anisotropic behavior to improve the mechanical and wear properties by using different scan strategy, especially in the case of 15–5 PH grade stainless steel is relatively sparse. Therefore, it is necessary to learn how mechanical and wear properties are improving in these three different scan pattern samples. At first, the temperature data at a specific point is captured by using a non-contact type pyrometer during printing and the detailed microstructural characterization of that particular region is analyzed. All three different scan pattern samples mostly show δ-ferrite and lath martensite (α') structure. The X-ray diffraction shows, there is formation of secondary precipitation phases like NbCr2, NbC, and Cu rich precipitation in all three different scan pattern samples. The electron back scattered diffraction (EBSD) result exhibits the island alternative scan pattern samples have mostly mixed orientation direction, a high fraction of retained austenite (͠ 0.004) and high angle grain boundaries (HAGBs) compared to the island scan pattern and cross hatch pattern samples. The island alternative scan pattern samples show maximum improved mechanical properties i.e. average ultimate tensile strength (UTS) of 1316 MPa and up to 20% of elongation amongst all deposited samples. Similarly, the alternative island scan pattern samples exhibit a high coefficient of friction (COF) irrespective of the applied load. The SEM image of the worn surfaces clearly demonstrates abrasion and adhesion type wear in all the three different scan pattern samples.

Facile synthesis and characterization of a magnetic biosorbent derived from sodium alginate and activated graphite schist: Experimental and statistical physics analysis for Mn(VII) remediation

H2O2-modified graphite schist (GS) and sodium alginate (SA) interface was loaded by Fe3O4 nanoparticles (MNPs) to prepare a magnetic biosorbent that was employed in removing Mn(VII) from solutions. The prepared GS/SA/MNPs adsorbent was investigated using a variety of techniques, including elemental mapping, TEM, XPS, FTIR, FESEM, EDX, XRD, XPS, and zeta potential. An experimental study supported by statistical physics calculations was carried out to obtain a new outline of the Mn(VII) uptake mechanism. The classical Freundlich and the statistical physical double-layer models adequately described the Mn(VII) uptake process at pH 3.0 and a temperature of 25–55 °C. The removed number of Mn ions (such as Mn+7 and Mn+2) per GS/SA/MNPs active site ranged from 0.70 to 0.84, indicating a mixed adsorption orientation driven by surface complexation and attraction forces mechanisms. The adsorption energies (∆E) calculated by the double-layer model ranged from 18.79 to 24.94 kJ/mol, suggesting that the interaction between Mn(VII) and GS/SA/MNPs was controlled by physical forces. Increasing the adsorption capacity at saturation (Qsat) from 333.14 to 369.52 mg/g with temperature proposed an endothermic capture process. Thermodynamic functions clarified the viability and spontaneity of Mn(VII) uptake on the GS/SA/MNPs adsorbent.

Diclofenac sodium drug adsorption isotherm on carbon xerogels via an advanced two layers model with two energies

In this work, four carbon xerogels (XCs) adsorbents, which were prepared by the polymerization of formaldehyde (F) and resorcinol (R) using cesium carbonate (Cs) as catalyst at 4 M ratios R/Cs = XCs-100, XCs-500, XCs-1000 and XCs-2000, were utilized to interpret and understand the adsorption mechanism at a molecular level of non steroidal anti inflammatory drug (NSAID), namely diclofenac sodium (DCF). Hence, Four adsorption isotherms were utilized to present the evolution of the adsorbed quantity (Qa) as a function of drug concentration describing the DCF adsorption on the four carbons xerogels at T = 298 K and at pH = 7. In addition, two other adsorption systems, describing the adsorption of DCF on XCs-500, were plotted by varying two experimental conditions: temperature and solution pH. All these experimental data were adjusted and analyzed via the advanced two layers model with two adsorption energies (A2LM2E), which was chosen as the most adequate statistical physics model. Furthermore, stereographic and energetic parameters of A2LM2E namely: the number of DCF molecules per XCs sites (n), the adsorbed quantity at saturation (Qas) and the concentrations at half saturation (C1 and C2) were estimated by a multi-variable non-linear regression. The fitting results indicated that the DCF drug molecules were docked with mixed and non-parallel orientations on the different XCs adsorbents. The investigation of the adsorbed quantity at saturation indicated that Qas increased as follows: Qas (XCs-2000) < Qas (XCs-100) < Qas (XCs-1000) < Qas (XCs-500), showing that the XCs-500 was more efficient for the adsorption of DCF drug than the other adsorbents. The calculated molar adsorption energies ΔE1 and ΔE2 for the studied adsorption systems affirmed the exothermic and the physical characters of the adsorption mechanism since ΔE1 and ΔE2 values were positive and inferior to 40 kJ/mol. Lastly, the XCs-100, XCs-500, XCs-1000 and XCs-2000 adsorbents presented unimodal pore size distributions (PSDs) centered at a pore radius of 8.38 nm, 7.17 nm, 6.05 nm and 5 nm, respectively. Finally, the estimated thermodynamic parameters such as the adsorption entropy (Sa), the Gibbs free enthalpy (G) and the internal energy (Eint) indicated that DCF adsorption on XCs-500 was spontaneous and exothermic process.

Microstructure, texture and recrystallization of heavily rolled CoCrFeNi medium entropy alloy

The microstructure and texture have been characterized in a CoCrFeNi medium entropy alloy after cold rolling to 85% and subsequent annealing at 550°C for 130 min. It is observed that the as-rolled microstructure is heterogeneous and comprises extended regions of either 〈110〉//ND or 〈111〉//ND orientations and volumes of mixed orientations. The microstructure also contains a large number of shear bands acting as preferential nucleation sites for recrystallization during annealing. Recrystallization generates annealing twins, which results in new components along the 〈110〉//ND fiber and other new orientations, thus making the texture of recrystallized regions fairly weak. Orientations demonstrating increased intensities in the recrystallization texture are identified as {113}〈332〉 and {236}〈385〉 components.