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Copyright of GeSec: Revista de Gestao e Secretariado is the property of Sindicato das Secretarias e Secretarios do Estado de Sao Paulo (SINSESP) and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The self-assembled monolayers (SAMs) process is one of the techniques used for the production of ultra-thin layers. The present work is therefore devoted to the study of the inhibition of zinc corrosion in a marine environment rich in H2S by SAMs based on Sargassum fluitans III. The protective effect of crude extracts of Sargassum fluitans on the surface of zinc using the SAMs process was evaluated by gravimetry and impedance on two different sites after three months of exposure. The formation of SAMs was characterized by FTIR, and the corrosion products formed on the surfaces were analyzed by XRD. The results obtained show that SAMs based on Sargassum fluitans III effectively inhibit zinc corrosion. [ABSTRACT FROM AUTHOR]

Controlling the evolution process of columnar grains is benefits to achieve microstructure regulation during subsequent hot processing in superalloys. In present research, it takes a Ni–Co–W superalloy as an example, aims to clarify the underlying connections between the compression direction and dynamic recrystallization (DRX) behaviors in microstructure evolution. The compression direction (CD) was parallel or perpendicular to [001] columnar has been defined as CD∥[001] and CD⊥[001], respectively. The columnar evolution and DRX characteristics under two sets of experimental during hot deformation were identified deeply. The results show that complete DRX is more easily to occur when CD⊥[001], but fine DRX grains are tendency to form when CD∥[001]. DRX nucleation within CD∥[001] and CD⊥[001] deformed microstructure under dislocation energy was discussed deeply. The critical size of nucleation is decreased while the nucleation density is increased in CD∥[001] with high dislocation density, which benefits to form numerous fine DRX grains along the original columnar boundaries. In addition, according to Taylor factors (TFs) criterion, TFs difference will always existed in CD∥[001], which promotes the necklace structure gradually replaced columnar structure and some of them developed into fine DRX bands. With increasing of trues strain, TFs difference gradually decreased in CD⊥[001], DRX nucleation was inhibited, thus the existed DRX grains further grow and finally coarse DRX grains were obtained. The findings clarified the flow behaviors and DRX characteristics of [001] columnar in two directions, and then proposed a microstructure control mechanism of superalloys with [001] columnar based on deformation vector and evolution decomposition.

Limited QCIs (QoS Class Identifiers) restrict the handling different service types with varying quality requirements. This necessitates research on QoS management to minimize latency and improve user experience, particularly for real-time applications like video conferencing and online gaming. This paper proposes a combined optimization scheme targeting QCI 3 to reduce latency. The approach involves disabling DRX, optimizing pre-allocation, and reducing the PDCP discard timer. The optimization performance is studied by taking the case of an e-sport game that demands low network latency, affecting the quality of the players' experience. The optimization scheme was validated through functionality, resource allocation, and air interface latency tests conducted under actual e-sport gaming conditions. Network latency was measured every minute to evaluate the impact of optimization on esports games running under QCI 7, QCI 3, and optimized QCI 3. In addition, air interface latency for optimized QCI 3 under networks with poor coverage and very high-capacity networks was compared to latency under QCI 8 (basic), QCI 7, and regular QCI 3. The optimization strategy demonstrated a significant reduction in air interface latency, up to 19% improvement compared to non-optimized QCI 3. It has reduced air interface latency's maximum, minimum, and standard deviation values during gameplay. The strategy also ensured concurrent operation with multiple QCI values without compromising other application’s throughput. The proposed optimization strategy effectively enhances the user experience by significantly reducing average latency and jitter.

The dissolution mechanism of the η-Ni3(Al0.5Nb0.5) phase during hot compression in Ni-based ATI718Plus superalloy has been investigated. The results indicate that with increasing deformation, the amount of dynamic recrystallization grains in the γ matrix increases, and the dissolution of the η phase tends to be accelerated. At the precipitation temperature of the η phase of 950 °C, the η phase area fraction decreased from 9.8% to 3.0% after deformation. The deformation promotes dislocation accumulation at the boundaries of the η phase, developing into subgrains and then evolving into DRX grains due to subgrain rotation. With increased strain, the subgrain rotations and DRX grain growths result in extrusion and subsequent fracture of the η phase. Due to strain incompatibility between the η phase and γ matrix, dislocation sustains are accumulated at their interfaces, which disrupts the η/γ semi-coherent interface, leading to localized amorphization and the decomposition of the η phase. Furthermore, dislocation surrounding the η phase can act as diffusion channels for solute elements, promoting the dissolution of the η phase and resulting in the element concentration gradient distribution from the η phase to the γ matrix.

The microstructure evolution of Mg-13Gd-4Y-2Zn-0.5Zr (wt.%) alloy with long-period stacking ordered (LPSO) phases after compression-torsion deformation (thereinafter referred to as CT deformation) at different temperatures was analyzed by optical microscopy (OM), scanning electron microscopy (SEM), x-ray diffraction (XRD) and electron back-scatter diffraction (EBSD) analysis, especially the evolution of LPSO phases during CT deformation. In addition, dynamic recrystallization (DRX) behavior during CT deformation and the impact of LPSO phase evolution on DRX behavior was explicated. The results showed the structures by order of appearance: lamellar LPSO phase (light kink—moderate kink—severe kink—almost no kink) and bulk LPSO phase (needle-like projections—tearing—dissolution—crushing) at increased CT deformation temperature. The proportion of DRXed grains gradually increased with CT deformation temperature, ranged from 11.6% at 350 °C to 40.9% at 480 °C. Apart from the increases in atomic thermal vibration and diffusion rate owing to increase in CT deformation temperature, the bulk LPSO phases at the grain boundary showed enhanced lattice rotation, which provided an ideal position for the nucleation of DRXed grains, and promoted the accumulation of strain gradient during deformation. Meanwhile, the second-phase particles distributed in the grain and grain boundary promoted DRX nucleation through PSN mechanism. [ABSTRACT FROM AUTHOR]

In this paper, the electron backscatter diffraction (EBSD) technique was used to analyze the dynamic recrystallization (DRX), twinning, slip behavior, and texture evolution during forging and subsequent extruding deformation. The results show that, as the degree of strain increased (forging to extruding), the degree of DRX increased, and the DRX mechanism changed from discontinuous DRX (DDRX) during forging to DDRX and continuous DRX (CDRX) during extruding. Particle stimulation nucleation (PSN) promoting DRX occurred during deformation. The deformation process mainly produced {10–12} twins (TTW) and played a role in coordinating the deformation. The slip behavior also changed according to an analysis of in-grain misorientation axes (IGMA) results, changing from slip-dominated with a basal slip to co-dominated with multiple slip modes, with the activation of mainly prismatic and pyramidal slip. Meanwhile, the strong basal texture at the beginning of the deformation also changed, and the texture strength decreased from 24.81 to 15.56. The weakening of the texture was mainly due to the formation of DRX grains and twins, as the newly formed DRX and twins reoriented. In the later stages of deformation, the activation of prismatic slip and pyramidal slip changed the basal texture component. Based on microstructural analysis, the improvement in mechanical properties was due to fine-grain strengthening and load-transfer strengthening. The ultimate tensile strength (UTS) was 370.5 MPa, the yield strength (YS) was 340.1 MPa, and the elongation (EL) was 15.6%. [ABSTRACT FROM AUTHOR]

To achieve a broad range of gradient strain from the rim to the center of a single specimen, the size of the high-throughput double-cone (DC) specimen was optimized using finite-element-model (FEM) simulation. As the deformation increased, the flow stress of the DC specimen quickly reached the maximum value, then gradually declined, and finally tended to be stable. The gradient microstructures corresponding to the gradient strains from the rim to the center of the DC specimen compressed at a certain temperature and strain rate were obtained by only one compression testing. As the equivalent strain increased, the degree of dynamic recrystallization (DRX) gradually rose from the rim to the center of the compressed DC specimen. However, when the equivalent strain and strain rate remained constant, the degree of DRX increased steadily with rising deformation temperature in the compressed DC specimens. Furthermore, during compression of the DC specimens at temperatures of 250 °C and 300 °C, the primary DRX mechanism was continuous dynamic recrystallization (CDRX). At temperatures of 350 °C and 400 °C, the DRX mechanism shifted, as both CDRX and discontinuous dynamic recrystallization (DDRX) were observed. This suggested that the DRX mechanism underwent a change as the deformation temperature increased.

The hot deformation behavior and the associated microstructural evolution (which were the keys to decide mechanical properties) were studied using different deformation conditions for the quaternary Al–Cu–Li–Zn alloy containing 1.0 wt% Zn. The constitutive equations and processing map were established. Dynamic recrystallization (DRX) was related to the orientation of the initial grains. The DRX rarely occurred in the grains with an orientation near Al and mainly occurred in the grains with an orientation near Al. Particle simulated nucleation (PSN) promoted by pre-existed coarse T1 phase particles was the main mechanism of the DRX when the deformation temperature was below 450 °C. In the temperature range of 450–500 °C with a strain rate of 0.01 s−1, the DRX occurred by grain boundary bulging or the increase in the cumulative misorientation, but only small fraction of the DRX grains appeared. This work provided an important guideline for the optimization of deformation techniques and microstructures.

Millimeter-wave (mm Wave) range is one of the critical suggestions of 5G portable systems because of its capacity to suit enormous traffic requests and a consistently expanding number of remote gadgets. Paging communicates, for clients in Idle Discontinuous Reception (IDRX) mode for vitality sparing, is one such vital capacity in a re-mote correspondence that needs alteration in exceptionally directional bar based transmissions. Because of the restricted spatial inclusion of directional bars, the paging transmission happens over various shafts, which builds the paging asset overheads of the system considerably. In this article, we present a novel paging system for the directional air interface in mm Wave-empowered 5G communications. [ABSTRACT FROM AUTHOR]

Copyright of Brazilian Dental Science is the property of Brazilian Dental Science Journal-ICT-UNESP and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

In this study, the hot-deformation behavior of a die-casted Mg–Al–Zn–Ca–Mn–Zr alloy was investigated in the temperature range of 548–673 K and the strain rate range of 0.0001–1 s−1. The constitutive equation and processing maps were also developed to describe the flow stress behavior. The numerical simulation result revealed an average activation energy of ∼139.4 kJ mol−1, which is lower than the previously reported AZ31 Mg alloys. Subsequently, the low activation energy imparted a high degree of dynamic recrystallization and was mainly attributed to alloying elements Ca, Mn, and Zr. For optimum hot working parameters, processing maps displayed two different domains, the temperature range of 573–673 K for a strain rate range of 0.001–0.01 s−1 with a peak efficiency of 33% and a temperature of 673 K at a high strain rate of 0.01 s−1 with a peak efficiency of 31%. The microstructure evolution confirmed the validity of parameters and revealed high dynamic recrystallization. The average grain size ∼21.1 μm, ∼15.4 μm, and ∼16.1 μm were achieved at temperatures of 573 K, 623 K, and 673 K under a strain rate of 0.001 s−1. The profuse grain refinement is attributed to the pronounced accumulation of dislocation on grain boundaries and on the eutectic phases. In addition, the morphology of the eutectic phases was broken with the increase in the strain rate and temperature. Thus, the α-Mg and eutectic phases bear the compressive stresses and promote the dynamic recrystallization activity. Last but not least, the double peak texture after hot deformation was developed, which is one of the engineers' main requirements for enhancing the Mg alloy's ductility. Based on the above discussion, the hot deformed specimens exhibited an ultimate compressive strength of ∼340 MPa and elongated to fracture >25%. Consequently, this study enables the understanding of the broad use of Mg–Zn–Al–Ca–Mn–Zr alloys for automobile applications.

In this study, {10–12} tensile twins (TTs) were induced in hot-rolled AZ31 Mg sheets via hot tension along the normal direction. The results demonstrate that the volume fraction of TTs at 2 mm/min is greatly lower than their counterparts at 0.5 mm/min at 100 °C and 200 °C. Dynamic recrystallization (DRX) can decrease twin nucleation rate during hot tensile when the strain rate reaches 2 mm/min. Decrease in critical resolved shear stress of non-basal slips at 200 °C enhances the deformation capability among grains, which dramatically reduces the volume fraction of TTs. Hence, TTs are hardly observed in 200°C-2mm/min sample. Tensile temperature significantly affects the morphology of TT lamellae. Grain boundaries prevents the longitudinal growth of the TTs, and then the thickness of TTs begins to grow to coordinate the deformation, resulting in fine TT lamellae in 100°C-0.5 mm/min. Compared with AR, the basal texture intensity of 100°C-2mm/min and 200°C-2mm/min increases and the occurrence of DRX is the main reason, while basal texture weakening of 100°C-0.5 mm/min and 200°C-0.5 mm/min depends on the formation of TTs. Compared with samples at 200 °C, the samples at 100 °C have higher tensile stresses. The maximum stress of 100°C-0.5 mm/min is 64.97 MPa when tensile strain reaches 0.15 owing to its highest dislocation density. 200°C-2mm/min possesses the highest hardness among the four tension samples, which is associated with the largest fraction of DRXed grains (68.8%) and its refinement strengthening effect. Dislocation strengthening exerts more influence on the hardness of 100°C-0.5 mm/min.

Nano partículas de (LaF3)0.75Er0.025Yb0.225 y (LaF3)0.75Er0.015Yb0.235 fueron sintetizadas utilizando el método de coprecipitación química y sometidas a tratamiento térmico de 200 °C, 400 °C y 600 °C respectivamente durante 2 horas. La estructura de las muestras fue analizada a través de la técnica de difracción de rayos X (DRX) y modelamiento RIETVELD por parámetros fundamentales usando el software TOPAS. El tamaño de los cristalitos se determinó a nivel nanométrico (entre 11.9 nm y 140.7 nm) y se verifico el aumento del tamaño de los cristalitos a medida que la temperatura del tratamiento térmico se incrementaba. Se pudo verificar el cambio de estructura hexagonal a romboédrica para las muestras sometidas a 600 °C de temperatura y un aumento significativo en la cristalinidad de las muestras por efecto del tratamiento térmico. Las imágenes SEM-EDS muestran los efectos descritos y proporcionan una vía para corroborar el crecimiento de las partículas (entre los 538 nm y 778 nm ), así como para obtener la composición elemental de las muestras. Finalmente los espectros Raman muestran una baja energía fonónica de las muestras, asegurando así que la perdida de las propiedades de emisión anti Stokes de los estados excitados de los iones lantánidos en las muestras por el efecto de quenching sea mínima.

In this paper, we report the effect of Nickel (Ni) nanoparticles (NPs) concentrations on the morphological, magnetic and mechanical properties of low-density polyethylene (LDPE) polymer matrix. Ni nanoparticles were prepared by solvothermal method. LDPE/Ni nanocomposites (NCs) films were prepared by solution mixing method for different Ni content (1, 3, 5, and 10 wt %). X-ray diffraction analysis indicates that, Ni NPs enhance the crystallinity of the polymer nanocomposite. Nanoindentation analysis of LDPE/Ni revealed an increase in hardness, indicating enhanced nanomechanical elastic properties. The magnetic properties of nanocomposite revealed a soft ferromagnetic behavior at room temperature. LDPE/Ni magnetic nanocomposites have shown potential for the development of materials with unique and tunable magnetic and mechanical properties. [ABSTRACT FROM AUTHOR]

In this paper, the electron backscatter diffraction (EBSD) technique was used to analyze the dynamic recrystallization (DRX), twinning, slip behavior, and texture evolution during forging and subsequent extruding deformation. The results show that, as the degree of strain increased (forging to extruding), the degree of DRX increased, and the DRX mechanism changed from discontinuous DRX (DDRX) during forging to DDRX and continuous DRX (CDRX) during extruding. Particle stimulation nucleation (PSN) promoting DRX occurred during deformation. The deformation process mainly produced {10–12} twins (TTW) and played a role in coordinating the deformation. The slip behavior also changed according to an analysis of in-grain misorientation axes (IGMA) results, changing from slip-dominated with a basal slip to co-dominated with multiple slip modes, with the activation of mainly prismatic and pyramidal slip. Meanwhile, the strong basal texture at the beginning of the deformation also changed, and the texture strength decreased from 24.81 to 15.56. The weakening of the texture was mainly due to the formation of DRX grains and twins, as the newly formed DRX and twins reoriented. In the later stages of deformation, the activation of prismatic slip and pyramidal slip changed the basal texture component. Based on microstructural analysis, the improvement in mechanical properties was due to fine-grain strengthening and load-transfer strengthening. The ultimate tensile strength (UTS) was 370.5 MPa, the yield strength (YS) was 340.1 MPa, and the elongation (EL) was 15.6%.

Magnesium and magnesium-based alloys are widely used in the transportation, aerospace and military industries because they are lightweight, have good specific strength, a high specific damping capacity, excellent electromagnetic shielding properties and controllable degradation. However, traditional as-cast magnesium alloys have many defects. Their mechanical and corrosion properties cause difficulties in meeting application requirements. Therefore, extrusion processes are often used to eliminate the structural defects of magnesium alloys, and to improve strength and toughness synergy as well as corrosion resistance. This paper comprehensively summarizes the characteristics of extrusion processes, elaborates on the evolution law of microstructure, discusses DRX nucleation, texture weakening and abnormal texture behavior, discusses the influence of extrusion parameters on alloy properties, and systematically analyzes the properties of extruded magnesium alloys. The strengthening mechanism is comprehensively summarized, the non-basal plane slip, texture weakening and randomization laws are comprehensively summarized, and the future research direction of high-performance extruded magnesium alloys is prospected. [ABSTRACT FROM AUTHOR]

The objective of this work was initially, it was a new field of research that deals with more advanced ceramic materials used in Biomaterials and Nanotechnologies, the second objective was to synthesize hydroxyapatite of high purity from natural resources for their application in Medicine. We can consider that this double objective has been achieved since on the one hand we have characterized these hydroxyapatites; on the other hand, this material is synthesized from several routes. Several techniques were used; including X-ray diffraction (XRD), scanning electron microscopy coupled with EDX microanalysis (SEM-EDX), differential thermal and gravimetric analyzes (DTA-TGA) and finally the Fourier transform infrared (FTIR) and X fluorescence (XRF). This study concerns the results of the synthesis of hydroxyapatites, in the field of Biomaterials, we mainly encounter ceramics, especially the uses and developments of osseointegration and bioactive ceramics based on calcium phosphate: hydroxyapatite (HAP), there are therefore uses of hydroxyapatite (HAP) in dental implants and filling materials and in orthopedic surgery. [ABSTRACT FROM AUTHOR]

To suppress the edge crack of the magnesium alloy sheet during the ordinary rolling process, a new rolling process named width-limited rolling was proposed in this paper. Width-limited rolling is a rolling method in which the width of the alloy sheet is limited by modifying the shape of the rollers, allowing a compressive stress field to form at the edge portion of the alloy sheet during rolling, resulting in the reduction of edge cracks. At present work, magnesium alloy sheets were separately subjected to ordinary rolling and width-limited rolling. The microstructure evolution and mechanical properties of the rolled sheets were investigated by EBSD, TEM, and XRD. The results exhibited that under the same rolling conditions, the sheet after ordinary rolling exhibited obvious edge cracks while no crack was found at the edge of the sheet after width-limited rolling. The edge crack suppressing effect was attributed to the reduction of the tensile stress along rolling direction during WLR, promoting the synchronous extension of the edge and center regions to suppress edge crack tendency. Microstructure observation showed that the compressive twins formed in the sheet after ordinary rolling usually exhibited as thin plates and cannot continue to fully develop due to the premature generation of the edge cracks. However, the compressive twins developed maturely in some of which double twins formed and various slip systems with different dislocation Burgers vectors occurred in the rolled sheet after WLR. More twin intersections and shear bands, providing more potential recrystallization nucleation sites, which are beneficial to weaken basal texture. With the cooperation of twinning and dislocation slip, the texture of the sheet after the width-limited rolling is weakened and the mechanical properties are improved.

Hallmark features of systolic heart failure are reduced contractility and impaired metabolic flexibility of the myocardium. Cardiomyocytes (CMs) with elevated deoxy ATP (dATP) via overexpression of ribonucleotide reductase (RNR) enzyme robustly improve contractility. However, the effect of dATP elevation on cardiac metabolism is unknown. Here, we developed proteolysis-resistant versions of RNR and demonstrate that elevation of dATP/ATP to ∼1% in CMs in a transgenic mouse (TgRRB) resulted in robust improvement of cardiac function. Pharmacological approaches showed that CMs with elevated dATP have greater basal respiratory rates by shifting myosin states to more active forms, independent of its isoform, in relaxed CMs. Targeted metabolomic profiling revealed a significant reprogramming towards oxidative phosphorylation in TgRRB-CMs. Higher cristae density and activity in the mitochondria of TgRRB-CMs improved respiratory capacity. Our results revealed a critical property of dATP to modulate myosin states to enhance contractility and induce metabolic flexibility to support improved function in CMs. [Display omitted] • Ubiquitylation-resistant variant RRB in a transgenic mice model (TgRRB) elevates dATP in the heart and improves function. • TgRRB-CMs show greater basal oxygen consumption due to changes in myosin state by dATP. • TgRRB-CMs respond to elevated function with higher pools of oxidative metabolites, elevated OXPHOS, FAO, and energy reserve. • Long-term mitochondrial remodeling may occur to accommodate for the higher energy demands of the high functioning TgRRB-CMs. [ABSTRACT FROM AUTHOR]

Cobalt-based superalloys are common materials for the manufacturing of various components used in aerospace applications. Conventional cobalt-based superalloys with a unimodal grain structure generally exhibit low strength and ductility at high temperatures. A bimodal grain structure of a cobalt-based superalloy, Co–20Cr–15W–10Ni (CCWN), was designed to achieve both high strength and ductility at high temperatures. The deformation behavior and tensile properties of a CCWN alloy with unimodal fine-grain (FG), coarse-grain (CG), and bimodal (FG/CG) structures were investigated at 900 °C. The microstructures and substructures after high-temperature deformation were examined via electron backscatter diffraction (EBSD) and electron channeling contrast imaging (ECCI) to determine the deformation mechanisms. The microstructural observation showed that the bimodal grain structure consisted of FG and CG domains. During high-temperature deformation at 900 °C, the FG structure was mainly deformed by dynamic recrystallization (DRX), maintaining a similar FG structure. The CG structure was mainly deformed by DRV, resulting in a small amount of DRX grains and a large amount of dynamic recovery (DRV) grains. However, the bimodal grain structures were mainly softened via DRX and transformed into a new bimodal structure, ultrafine grain (UFG) and FG. The FG domains tended to deform via dislocations, and the CG domains via twinning. The high-temperature tensile tests revealed that the bimodal-structured alloy exhibited both higher strength and ductility than those of the alloy samples with unimodal FG or CG structure. This is associated with the newly developed UFG/FG structures in the bimodal grain-structured samples during high-temperature deformation. This work may provide new insight into the development of high-temperature alloys with bimodal grain structures. [ABSTRACT FROM AUTHOR]

Las cáscaras de naranja (Citrus sinensis) son residuos lignocelulósicos abundantes que pueden ser utilizados como fuente de carbono para obtener sólidos con potencial catalítico en la transformación de terpenos y sus óxidos en productos de valor agregado. Esta investigación buscó evaluar la isomerización de óxido de α-pineno a aldehído canfolénico, utilizando un catalizador obtenido de cáscaras de naranja. El material OAC-Zn se obtuvo por activación de las cáscaras con ZnSO4.7H2O, seguido de tratamiento térmico a 500 °C; también se obtuvo un sólido de la pirólisis de la cáscara a 500 °C (OC-500). Mediante DRX se identificó la presencia de ZnO y ZnS en OAC-Zn; los análisis por TGA indicaron estabilidad térmica en OAC-Zn y OC-500; las imágenes SEM mostraron superficies porosas de diferente morfología, así como la presencia de microporosidad en OC-500 y de mesoporosidad en OAC-Zn, que fueron confirmadas mediante adsorción física de nitrógeno. En los análisis EDX se identificaron los elementos C, O, Zn y S en OAC-Zn; los resultados de TPD-NH3 mostraron que los sólidos contenían acidez media y débil. Se sintetizó aldehído canfolénico con selectividad de 96 % sobre un material carbonoso mesoporoso, a partir de cáscaras de naranja utilizando ZnSO4.7H2O como agente activador

Orange peels (Citrus sinensis) are an abundant lignocellulosic residue that can be used as a carbon source to obtain solids with catalytic potential in the transformation of terpenes and their oxides into value-added products. This research seeks to evaluate the isomerization of a-pinene epoxide to campholenic aldehyde using a catalyst obtained from orange peels. The material OAC-Zn was obtained by activation of orange peel with ZnSO4.7H2O followed by thermal treatment at 500 °C; an additional solid was obtained from orange peel by pyrolysis at 500 °C (OC-500). XRD revealed the presence of ZnO and ZnS in OAC-Zn; TGA analysis indicated thermal stability in OAC-Zn and OC-500 materials; SEM images showed porous surfaces of different morphology, and the presence of microporosity in OC-500 and mesoporosity in the OAC-Zn that was confirmed by physical nitrogen adsorption. The elements C, O, Zn and S were identified in OAC-Zn by EDX analysis. The results of TPD-NH3 showed that the solids contained medium and weak acidity. Campholenic aldehyde was synthesized with a 96 % selectivity over the material OAC-Zn. [ABSTRACT FROM AUTHOR]

After years of intense research using structural, biological, and biochemical experimental procedures, it is clear that myosin molecules are essential for striated muscle contraction. However, this is just the tip of the iceberg of their function. Interestingly, it has been shown recently that these molecules (especially myosin heavy chains) are also crucial for cardiac and skeletal muscle resting state. In the present review, we first overview myosin heavy chain biochemical states and how they influence the consumption of ATP. We then detail how neighboring partner proteins including myosin light chains and myosin binding protein C intervene in such processes, modulating the ATP demand in health and disease. Finally, we present current experimental drugs targeting myosin ATP consumption and how they can treat muscle diseases. [ABSTRACT FROM AUTHOR]

Copyright of Revista Ciencia y Tecnología Agropecuaria is the property of Agrosavia and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Temperature and strain rate related dynamic recrystallization (DRX) and its inherited effects on ductile fracture have become an urgent issue which impede accurate prediction of fracture strain and restrict formability for 7075 aluminum alloy in hot deformation process. In order to precisely elaborate the ductile fracture behavior of 7075 aluminum alloy during hot forming process and accurately predict the initiation of ductile fracture, an extended ductile fracture criterion (DFC) at elevated temperature was established considering DRX effects and various stress states. The relationship between fracture strain and Z parameter is revealed in DRX and DRX-free region, respectively. It is noted that fracture strain decreases with the increasing Z parameter in DRX region, while Z parameter has little effect on the fracture behavior in DRX-free region. Consequently, the Z parameter embedded DRX model is introduced into the modified Mohr–Coulomb (MMC) DFC under distinct stress states at elevated temperatures for 7075 aluminum alloy. Based on the Abaqus/Explicit platform, the proposed ductile fracture model is implemented in finite element simulation via VUMAT. Hot forming of T-shaped parts is carried out, and the predicted fracture scenarios including damage evolution, volume fraction of DRX are validated by experimental results. [ABSTRACT FROM AUTHOR]

Our research is based on the production of BNT ceramics, abbreviated as NBMTZNZ. And study its structural and electrical properties. Using x-rays, electronic scanning, and non-electrical measurements, we analyzed the samples. The results obtained are of considerable value, allowing them to be exploited to develop the use of our compound. [ABSTRACT FROM AUTHOR]

This study opens up exciting possibilities for the application of Co-MOF, a Metal-Organic Framework ([Co(5-NH 2 -bdc)(bpy)0.5(H 2 O)]3·2H 2 O), in the efficient removal of heavy metals (Pb2+, Hg2+, Cd2+, Cu2+) from water. The removal mechanism combines ion exchange and adsorption, influenced by the ionic radius of the metal ions. Langmuir's model determined maximum adsorption capacities (Qm), showing a proportional increase with the ionic radius of heavy metals: 75.47 mg/g (Cu2+), 344.82 mg/g (Cd2+), 485 mg/g (Hg2+), and 526.31 mg/g (Pb2+). Free Gibbs energy, inversely proportional to the metal's ionic radius, was determined as −36.43 kKj/mol (Cu2+), −28.67 Kj/mol (Cd2+), −24.13 Kj/mol (Pb2+), and −21.67 Kj/mol (Hg2+). The pseudo-second-order mechanism explained heavy metal removal, except for Cu2+, due to continuous ion exchange. Reutilization experiments showed a decrement in efficacy in the second cycle. Filtration experiments demonstrated a lower removal percentage (close to 60 %) and confirmed the competitive activity of Co-MOF compared to other MOFs, particularly in Cd2+ removal, with superior rate constants and maximum adsorption capacities. [Display omitted] • Removal of Heavy Metals Pb2+, Hg2+, Cd2+ and Cu2+ from Water using crystalline MOFs. • Kinetic and isothermal studies on the adsorption process of Pb2+, Hg2+, Cd2+ and Cu2+. • Co-MOF with high adsorption activity for the removal of Cd2+ from water. • Combination of ion exchange and adsorption mechanisms for heavy metal removal from water. • Pseudo-second-order mechanism confirmed for the removal of heavy metals Pb2⁺, Hg2⁺, Cd2⁺, and Cu2⁺. [ABSTRACT FROM AUTHOR]

actualmente, se están produciendo ceras por hidrotratamiento de aceite de palma, sin embargo, los productos obtenidos no siempre alcanzan las condiciones de punto de fusión y dureza requeridas por la industria cosmética. Debido a esta problemática, el interés de este trabajo fue evaluar un proceso de cristalización sin solvente con el objetivo de incrementar la temperatura de fusión y los rendimientos másicos de la biocera, acercándolos a los intervalos de los valores de las propiedades fisicoquímicas que requiere el mercado. Para cumplir con este propósito, se determinó el rango operativo de la temperatura de cristalización por calorimetría diferencial de barrido (dsc) y difracción de rayos X (drx). Una vez conocidos los puntos de cristalización, se procedió a calentar la muestra hasta los 50 °C y seguidamente se realizó un enfriamiento controlado hasta que la biocera 1 alcanzara los 40 °C para y de 30 °C para la biocera 2, y a estas temperaturas se consiguieron dos fracciones (líquida y sólida). Las fracciones sólidas presentaron un incremento en la temperatura de fusión de 47 °C a 49 °C para la biocera 1, y de 45 ºC a 47 ºC para la biocera 2. El proceso de cristalización no separó las diferentes familias de compuestos presentes en las bioceras, por lo que no se evidenciaron cambios significativos en los parámetros índice de acidez, saponificación y yodo. Además, futuras investigaciones en otras técnicas de refinación complementarias a la cristalización, como neutralización y decoloración, permitirán a la biocera de palma cumplir con los criterios de calidad internacionales para ser utilizada como ingrediente en las industrias cosmética y farmacéutica.

Flow behavior of three near eutectic Al–Si alloys with the same chemical composition but different average eutectic Si sizes (A1, 1.7 μm; A2, 4.4 μm; A3, 8.2 μm) was investigated by isothermal compression tests conducted on a Gleeble-3500 thermal simulator under four different temperatures (350 °C, 400 °C, 450 °C, and 500 °C) and four different strain rates (0.01 s−1, 0.1 s−1, 1 s−1, and 5 s−1), with a focus on the effect of eutectic Si size. Not only the flow behavior but also the processing map of near eutectic Al–Si alloys are affected by eutectic Si size. The overall trends of the flow stress–strain curves of the three alloys are similar, but their steady flow stresses σs are different: A1 alloy has the largest σs, followed by that of A3. Strain-compensated constitutive equations in the hyperbolic sine form were constructed to describe the flow stress behavior of the three alloys. Materials constants of the constitutive equations depend on eutectic Si size. The processing maps of the three alloys exhibit different characteristics. The instability domain of A2 alloy is restricted to strain rates larger than about 0.4 s−1, in contrast to the case of A1 and A3 alloys in which the instability domain occurs at both low and high strain rates. The results presented in this study indicate that eutectic Si size is an indispensable factor to be considered when dealing with the hot working of Al–Si alloys.

This article presents the results of applying three archaeometry techniques in archaeological ceramics from the upper river Madeira region in Amazonia. The first consists of the nuclear technique, neutron activation analysis (INAA), to identify the trace elements of the clay sources used in the production of the vessels. The second, non-nuclear X-ray diffraction (XRD), was used to characterise the mineral phases of each clay source. The third technique, electron paramagnetic resonance spectroscopy (EPR), estimated burning temperature related to the production stage of the artefacts. This approach made it possible to understand technological choices linked to selecting specific clay sources. The results suggest that different indigenous groups that inhabited the region between 940 and 760 B.P selected three clay sources to produce their vessels.

Resumen En la arqueología del Nordeste argentino son escasos los trabajos que estudian las condiciones de quema de la alfarería prehispánica, no habiéndose aplicado técnicas físico-químicas que midan las transformaciones que sufre la pared cerámica durante el proceso de cocción. Con el propósito de revertir este estado de situación, aplicamos difracción de rayos X, análisis térmico diferencial y termogravimétrico, y dilatometría sobre 31 muestras de cerámicas arqueológicas recuperadas en los sitios Los Tres Cerros 1 y Cerro Tapera Vázquez (Delta Superior del río Paraná). La mayoría de las muestras (i.e., contenedores restringidos y no restringidos, campanas y cuchara) fue cocida a temperaturas superiores a 550/650 ºC e inferiores a 800 ºC; cuatro no superaron los 550/650 ºC y dos fueron sometidas a temperaturas superiores a los 800/900 ºC. A partir de la integración de estos resultados con evidencia etnoarqueológica, experimental y arqueológica interpretamos el amplio rango de temperaturas de cocción detectado (< 550 ºC y > 800 ºC) como un indicador de quemas en estructuras abiertas (i.e., fogones o pozos). Esta información nos permitió discutir hipótesis sobre las condiciones de cocción propuestas en investigaciones previas y plantear a futuro un programa experimental que permitirá conocer distintos aspectos de las quemas prehispánicas.

In this paper, the dynamic recrystallisation (DRX) behaviour under the strain rate of 0.1 s−1, 1 s−1 and 10 s−1 within the deformation temperature of 900°C∼1100°C of Ti-Zr microalloyed low carbon steel with different Zr content was studied using Gleeble-3800 thermal simulation test machine. The stress–strain curves of investigated steels were obtained under the diferent deformation conditions, and the thermal deformation equation and DRX volume fraction model are established based on the stress–strain curve. The result showed that the peak stress, critical stress and deformation activation energy (496.2 kJ mol−1) of the Ti-Zr steel containing 0.091 wt% Zr were higher than those of the steels with 0.035 and 0.073 wt% Zr. The increase of Zr content will increase the deformation activation energy of Ti-Zr steel and inhibit the growth of austenite DRX grains of Ti-Zr steel at high temperature. When the deformation conditions are the same, the DRX degree of austenite of Ti-Zr steel will first decrease and then increase with the increase of Zr content. [ABSTRACT FROM AUTHOR]

To suppress the edge crack of the magnesium alloy sheet during the ordinary rolling process, a new rolling process named width-limited rolling was proposed in this paper. Width-limited rolling is a rolling method in which the width of the alloy sheet is limited by modifying the shape of the rollers, allowing a compressive stress field to form at the edge portion of the alloy sheet during rolling, resulting in the reduction of edge cracks. At present work, magnesium alloy sheets were separately subjected to ordinary rolling and width-limited rolling. The microstructure evolution and mechanical properties of the rolled sheets were investigated by EBSD, TEM, and XRD. The results exhibited that under the same rolling conditions, the sheet after ordinary rolling exhibited obvious edge cracks while no crack was found at the edge of the sheet after width-limited rolling. The edge crack suppressing effect was attributed to the reduction of the tensile stress along rolling direction during WLR, promoting the synchronous extension of the edge and center regions to suppress edge crack tendency. Microstructure observation showed that the compressive twins formed in the sheet after ordinary rolling usually exhibited as thin plates and cannot continue to fully develop due to the premature generation of the edge cracks. However, the compressive twins developed maturely in some of which double twins formed and various slip systems with different dislocation Burgers vectors occurred in the rolled sheet after WLR. More twin intersections and shear bands, providing more potential recrystallization nucleation sites, which are beneficial to weaken basal texture. With the cooperation of twinning and dislocation slip, the texture of the sheet after the width-limited rolling is weakened and the mechanical properties are improved. [ABSTRACT FROM AUTHOR]

Magnesium and magnesium-based alloys are widely used in the transportation, aerospace and military industries because they are lightweight, have good specific strength, a high specific damping capacity, excellent electromagnetic shielding properties and controllable degradation. However, traditional as-cast magnesium alloys have many defects. Their mechanical and corrosion properties cause difficulties in meeting application requirements. Therefore, extrusion processes are often used to eliminate the structural defects of magnesium alloys, and to improve strength and toughness synergy as well as corrosion resistance. This paper comprehensively summarizes the characteristics of extrusion processes, elaborates on the evolution law of microstructure, discusses DRX nucleation, texture weakening and abnormal texture behavior, discusses the influence of extrusion parameters on alloy properties, and systematically analyzes the properties of extruded magnesium alloys. The strengthening mechanism is comprehensively summarized, the non-basal plane slip, texture weakening and randomization laws are comprehensively summarized, and the future research direction of high-performance extruded magnesium alloys is prospected.

Four new hybrid organic-inorganic compounds based on 1,4-cimethylpiperazinium, [C6H16N2M(SCN)4]·2H2O (M = Co(1), Ni(2)), [(C6H16N2)Cd(SCN)4] (3), and [C6H16N2(SCN)2] (4), were prepared by the evaporation crystal growth method at room temperature. These complexes were characterized by their X-ray crystal structure; spectroscopic methods such as FTIR analysis supported the presence of surface ligand groups of thiocyanates and identified the vibrational absorption bands. The piperazinium ring adopts a slightly distorted chair conformation which is more stable because it does not have any steric hindrance or steric repulsion between the hydrogen bonds and which favors the entities coordination. Intermolecular interactions were investigated by Hirshfeld surfaces and contact enrichment tools. In the crystals, extensive intermolecular interactions have been used in the self-assembly of motifs, including strong H-bonds. The components are linked mainly by N-H...S, O-H...S, and N-H...N hydrogen-bonding interactions, resulting in a three-dimensional network. The arrangements of the anions and cations in the solids are governed not only by the size and symmetry of the cations, but also by the non-covalent bonds in the crystal structures. [ABSTRACT FROM AUTHOR]

Energy saving in User Equipment (UE) is one of the important issues for limited sources of power in the device. It is critical for the UE to maximize its energy efficiency. In this paper, we have presented two stochastic models, namely the Markov model and semi-Markov model, for the UE based on the states of discontinuous reception (DRX) mechanism, i.e., a power saving method in mobile communication networks. Explicit expressions are derived for transient and steady-state system size probabilities for the Markov model. For the semi-Markov model, steady-state probabilities are computed. Further, the performance measures such as mean and variance are computed for both models. Using these models, based on the states of DRX mechanism, energy saving in the UE is calculated. Finally, sensitivity analysis is performed in which the results obtained are compared for both models. Numerical results obtained in this paper ensure that energy saving can be maximized in the UE using the Markov modelling of DRX mechanism rather than semi-Markov modelling. The energy saving using the Markov model is atleast 33.19 % more than the semi-Markov model. Also, for energy saving in the UE, the semi-Markov model for DRX mechanism is compared with the Markov model. The semi-Markov models for the DRX mechanism are available in the literature without considering the packet arrivals. Our analysis of DRX mechanism and conclusion on its performance can be designed and implemented to an extension for the existing DRX mechanism. We believe that, these models can also be extended to study the energy saving of hardware and other components of the system. [ABSTRACT FROM AUTHOR]

The thermal compression tests of Ti–Nb alloy under T = 790–940 °C and ε˙ = 0.001–10s−1 were carried out on the thermal simulation testing machine of Gleeble-3500. The flow stress curves were obtained, and the high-temperature rheological properties of the alloy were analyzed. The 3D activation energy maps were calculated and constructed. The LSSVM model of constitutive relation was established, and the penalty coefficient γ and kernel parameter δ of the LSSVM model were optimized by the genetic algorithm (GA). The constitutive model of the alloy based on the GA-LSSVM algorithm was constructed. The predicted value of the model was also compared with the experimental data. The polar reciprocity model (PRM) and dynamic material model (DMM) were used to establish the 3D processing map of the alloy and appropriate thermal processing parameters. The results indicated that T and ε˙ have a great influence on the flow stress of Ti–Nb alloy. Ti–Nb alloy is a negative temperature-sensitive and a positive strain rate-sensitive material. The correlation coefficient (R) of the GA-LSSVM algorithm constitutive model is 0.9958. The model has high prediction accuracy and strong generalization ability, which provide a new method for establishing a high-temperature constitutive model of materials. The PRM processing map is more accurate in optimizing the processing parameters of Ti–Nb alloy than that of the DMM processing map through analyzing the 3D processing map and observing the microstructure. The instability modes in the instability region of the alloy mainly include local flow. The stability region's predominant deformation mechanism is DRX. The 870–940 °C and 0.001–0.01s−1 are the best parameters during the processing of Ti–Nb alloy.

Thermal deformation behavior of a Ni-Cr-Fe superalloy billet were investigated by hot compression experiments under temperatures of 900–1200 °C and strain rates of 0.001–1 s−1, and the corrosion properties of the superalloy after thermal deformation were also evaluated by electrochemical tests. Compression experiments determined that lower strain rates and higher temperatures reduce the superalloy's stress levels. The Arrhenius-type model accurately described the thermal deformation behavior of the superalloy. Furthermore, the optimal hot working domain was identified between 1120 and 1170 °C and strain rates of 0.001–0.01 s−1. Microstructure observations showed that the dynamic recrystallization (DRX), characterized by grain boundary bending nucleation and consumption of numerous dislocations is the main mechanism leading to grain refinement during thermal deformation. The results of the electrochemical corrosion tests proved that the corrosion predominantly occurred near the grain boundaries (GBs) of deformed grains, worsening with increased deformation temperatures. • Thermal deformation of a Ni-Cr-Fe superalloy over a wide range of temperatures and strain rates. • The Arrhenius-type model and hot processing maps were established. • The microstructure and DRX mechanisms depend on compression process parameters. • The difference in corrosion resistance was closely associated with the evolution of microstructure. [ABSTRACT FROM AUTHOR]

FeCrAl alloys have the opportunity to replace current Zr-based cladding materials in light water reactors, and dynamic recrystallization (DRX) plays an important role on microstructural controlling of FeCrAl alloys during hot or warm deformation, such as forging, hot rolling, extrusion. In this research, dynamic recrystallization mechanism of FeCrAl alloy has been systematically investigated by microstructure characterization after isothermal compression. Results show that deformation strain rate and temperature could significantly influence microstructure and DRX mechanism of FeCrAl alloy. When deformed at 0.1s−1, prior grains become long strip with serrated boundaries and are refined by geometric dynamic recrystallization (GDRX). Prior grains are not separated by high angle grain boundaries (HAGB) even deformed at 1200 °C, because strain is too small to impingement of HAGB. Whereas, when deformed at 10s−1 strain rate, there are lots of sub-boundaries with about 2° misorientation within grains, and several strain-free grains are found located at boundaries when deformed at 900 °C or 1000 °C, while the prior grains are divided by HAGB and equiaxed grains are formed at 1100 °C. It was found that mechanism of DRX changes from discontinuous dynamic recrystallization (DDRX) to continuous dynamic recrystallization (CDRX) with increasing temperature from 900 °C to 1100 °C. The phenomenon results from the dislocation movement behaviors changes with increasing temperature. This research will provide meaningful guidance for industrial application of FeCrAl alloys. [ABSTRACT FROM AUTHOR]

• The effect of deposition time on the structural properties NiO thin films. • Calculating taille the crystallite and strain based on x-rays using several methods. • Comparison of experimental results with theoretical results based on DFT calculations. • Calculation of elastic constants and mechanical properties based on DFT. A comparison between the experimental investigation and theoretical calculations is the goal of this research. This research is divided into two sections. The first one deals with a structural analysis, using X-rays, of thin layers of nickel oxide obtained through a simple chemical process. Utilizing DFT computations, the second section examines the elastic and structural properties. In the experimental part, we prepared thin layers of nickel oxide using the chemical spray pyrolysis (CSP) method for a solution of nickel chloride dehydrate (NiCl 2.6H 2 O) dissolved in distilled water on glass substrates heated to a temperature of 400C°. The concentration of the solution used is 0.1 mol/L. We changed the deposition time as follows: 5 min, 10 min, 15 min and 20 min. After preparing the nickel oxide layers, we conducted an analytical study of the various crystalline and lattice properties using X-ray diffraction. The analytical study using X-rays confirmed all the films (NiO) were crystallized in the cubic structure; the lattice parameter a is estimated to be 4.17 Å. The film is oriented along the (1 1 1) and (2 0 0) plane. Theoretical calculations confirmed the crystalline properties of NiO compound. The obtained values ​​of elastic constants proved that the studied material is mechanically stable. The value of the B/G ratio is 3.99, the material studied presents ductile behavior. The value of anisotropy coefficient A obtained at 0 GPa for our material is different to 1, thus indicating that it is elastically anisotropic. [ABSTRACT FROM AUTHOR]