The reaction kinetics of burnt lime (CaO) in contact with sea water has been elucidated and compared to its behaviour in fresh water. In the first minutes of contact between burnt lime and water, it "slaked" as CaO reacted with water to yield calcium hydroxide (Ca(OH)2). Subsequently, calcium hydroxide reacted with magnesium, sulphate and carbonate from the sea water to yield magnesium hydroxide (Mg(OH)2), calcium sulphate dihydrate (gypsum, CaSO4·2H2O) and calcium carbonate (CaCO3), respectively. In a closed system of 1% CaO in natural sea water (where the supply of sulphate, magnesium and carbonate is limited), more than 90% reacted within the first 5 hours. It is foreseen that in an open system, like a marine fjord, it will react even faster. The pH 8 of sea water close to the CaO particle surface will immediately increase to a theoretical value of about 12.5 but will, in an open system with large excess of sea water, rapidly fall back to pH 10.5 being equilibrium pH of magnesium hydroxide. This is further reduced to < 9 due to the common ion effect of dissolved magnesium in sea water and then be diluted to the sea water background pH, about 8. Field test dosing CaO particles to sea water showed that the pH of water between the particles stayed around 8.

Eco-friendly betanin/clay minerals hybrid materials with good stability were synthesized combining natural betanin molecules extracted from beetroot with 2:1 type palygorskite (Pal) and 1:1 type halloysite (Hal), respectively. It was found that the adsorption, grinding and heating treatment played a key role to enhance the interaction between betanin and clay minerals during preparation process, which favored improving the thermal stability and solvent resistance of natural betanin. The L* and a* values of the betanin/Pal and betanin/Hal hybrid materials were 64.94 and 14.96, 62.55 and 15.48, respectively, indicating that betanin/Hal exhibited the better color performance. The structural characterizations confirmed that betanin was mainly adsorbed on the outer surface of Pal or Hal through hydrogen-bond interaction, and part of them also were entered into the inner surface of Hal via electrostatic interaction. Therefore, Hal preferred to improve the color properties, heating stability and solvent resistance of natural betanin due to its structural features compared with Pal.

ZnS-CdS composite nano-powder doped with (0.01 mol %) Cobalt has been collected by a co-precipitation process at 300 K. The sample is characterized by structural, combined spectroscopic methods and magnetic studies. The prepared samples were belonging to cubic structure no impurity phases were observed. Doping of cobalt increase the neighborhood strain assessment and a decreases lattice constants decides from x-ray diffraction data. The crystallite size is 10.42nm. From UV-absorption and EPR studies revealed that the energy band gap of Co2+ doped ZnS-CdS composite nanopowder and extension of sp-d exchange interactions and common d-d transitions. The variation in the energy bandgap varies as a function of cobalt concentration is due to structural modification. Photoluminescence spectrum reveals the defect-related emissions and shows the formation of luminescence. FT-IR spectrum confirmed the feature vibrational manner of Zn, Cd, O–H and sulfide ions are in the host lattice. The doping-induced magnetic properties are studied by vibrating sample magnetometer which matches with the theoretical values besides ferromagnetic nature. Magnetic studies confirm the ferromagnetic nature of the material. Surface morphology and chemical homogeneity studies were carried out by using SEM with EDAX. Transmission electron microscope recommends the crystalline nature of nanoparticles, with average particle size is of the order of 20-100nm.

A series of novel superabsorbent composites of poly(acrylic acid)/semicoke were prepared by polymerization of acrylic acid using ammonium persulphate as initiator, N,N’-methylenebisacrylamide as crosslinker and semicoke which was the by-product of coal carbonizing as the inorganic components. FTIR and SEM analysis indicated that the superabsorbent composites had been successfully polymerized and the semicoke participated into the construction of 3D polymeric network. Meanwhile, the effects of initiator, crosslinker, semicoke, neutralization degree as well as the pH value were investigated, and the results showed that superabsorbent composites containing 10% of semicoke possessed the maximum water absorbency of 584 g/g in distilled water and 75 g/g in 0.9 % NaCl solution. The superabsorbent composites kept the high water absorbency within a wide pH range of 4-11, and still exhibited better re-swelling capability even after seven times. The superabsorbent composite with the excellent performance is a potential water-retaining agent used in the agriculture.

Herein, we present a combination of experimental and computational study on the mitochondrial F0F1-ATPase nanotoxicity inhibition induced by single-walled carbon nanotubes (SWCNT-pristine, SWCNT-COOH). To this end, the in vitro inhibition responses in submitochondrial particles (SMP) as F0F1-ATPase enzyme were strongly dependent on the concentration assay (from 3 to 5 µg/ml) for both types of carbon nanotubes. Besides, both SWCNTs show an interaction inhibition pattern like the oligomycin A (the specific mitochondria F0F1-ATPase inhibitor). Furthermore, the best crystallography binding pose obtained for the docking complexes based on the free energy of binding (FEB), fit well with the previous in vitro evidences from the thermodynamics point of view. Following an affinity order as: FEB (oligomycin A/F0-ATPase complex) = -9.8 kcal/mol > FEB (SWCNT-COOH/F0-ATPase complex) = - 6.8 kcal/mol ~ FEB (SWCNT-pristine complex) = -5.9 kcal/mol. With predominance of van der Waals hydrophobic nanointeractions with key F0-ATPase binding site residues (Phe 55 and Phe 64). By the other hand, results on elastic network models, and fractal-surface analysis suggest that SWCNTs induce significant perturbations by triggering abnormal allosteric responses and signals propagation in the inter-residue network which could affect the substrate recognition ligand geometrical specificity of the F0F1-ATPase enzyme in order (SWCNT-pristine > SWCNT-COOH). Besides, the performed Nano-QSTR models for both SWCNTs show that this method may be used for the prediction of the nanotoxicity induced by SWCNT. Overall, the obtained results may open new avenues toward to the better understanding and prediction of new nanotoxicity mechanisms, rational drug-design based nanotechnology, and potential biomedical application in precision nanomedicine.

Single nanowires (NWs) are of great importance for optoelectronic applications, especially solar cells serving as powering nanoscale devices. However, weak off-resonant absorption can limit its light-harvesting capability. Here, we propose a single NW coated with the graded-index dual shells (DSNW). We demonstrate that with appropriate thickness and refractive index of the inner shell, the DSNW exhibits significantly enhanced light trapping compared with the bare NW (BNW), and the NW only coated with the outer shell (OSNW) and the inner shell (ISNW), which can be attributed to the optimal off-resonant absorption mode profiles due to the improved coupling between the reemitted light of the transition modes of the leak mode resonances of the Si core and the nanofocusing light from the dual shells with the graded refractive index. We found that the light absorption can be engineered via tuning the thickness and the refractive index of the inner shell, the photocurrent density is significantly enhanced by 134% (56%, 12%) in comparison with that of the BNW (OSNW, ISNW). This work advances our understanding of how to improve off-resonant absorption by applying graded dual-shell design and provides a new choice for designing high-efficiency single NW photovoltaic devices.

This study identifies new Alkali Activated Composite Mud Mortar to alternate Cement Mortar used for laying masonry works. This study handles both experimental and numerical analysis of strength and durability for mortar, especially bond strength along mortar and brick joints have studied detail and compared with ANSYS. The bond strength has estimated through the triplet brick prism of shear behavior. The strength and deformation characteristics of masonry constituents obtained from these tests depend on the actual composite conduct of masonry. There is always a good reception for environmentally friendly, low energy, new construction materials, and used in preparing mortar/brick unit combinations all around the world. Also, this study fulfills those requirements. Especially, masonry laid with the mud mortar meets all. Fly Ash, Ground Granulated Blast furnace Slag, and Quarry Dust have utilized the new composites' preparation with 8Molority, 10Molority developed excellent strength. The composite specimens are having compression and bond strength, ranging from 4.84-5.14 and 0.12-0.18N/mm2. The mixed ratio of materials has taken (0.5 parts of Fly Ash, 0.5 parts of Steel Slag, 1.75 parts of Soil, and 0.25 parts of Quarry Dust). The samples tested resistance against acidic, sulfate, and alkalinity indicated PH values less than 7 and 9 simultaneously. Compression strength varied from 10-20% and gained more and fit composite used for mortar in masonry works.

In recent years, the photophysical properties of crystalline metal-organic frameworks (MOFs) have become increasingly relevant for their potential application in light-emitting devices, photovoltaics, nonlinear optics and sensing. The availability of high-quality experimental data for such systems makes them ideally suited for a validation of quantum mechanical simulations, aiming at an in-depth atomistic understanding of photophysical phenomena. Here we present a computational DFT study of the absorption and emission characteristics of a Zn-based surface-anchored metal-organic framework (Zn-SURMOF-2) containing anthracenedibenzoic acid (ADB) as linker. Combining band-structure and cluster-based simulations on ADB chromophores in various conformations and aggregation states, we are able to provide a detailed explanation of the experimentally observed photophysical properties of Zn-ADB SURMOF-2: The unexpected (weak) red-shift of the absorption maxima upon incorporating ADB chromophores into SURMOF-2 can be explained by a combination of excitonic coupling effects with conformational changes of the chromophores already in their ground state. As far as the unusually large red-shift of the emission of Zn-ADB SURMOF-2 is concerned, based on our simulations, we attribute it to a modification of the exciton coupling compared to conventional H-aggregates, which results from a relative slip of the centers of neighboring chromophores upon incorporation in Zn-ADB SURMOF-2.

The exfoliation of graphene has opened a new frontier in material science with a focus on 2D materials. The unique thermal, physical and chemical properties of these materials have made them one of the choicest candidates in novel mechanical and nano-electronic devices. Notably, 2D materials such as graphene, MoS2, WS2, h-BN, and Black Phosphorus have shown outstanding lowest frictional coefficients and wear rates, making them attractive materials for high-performance nano-lubricants and lubricating applications. The objective of this work is to provide a comprehensive overview of the most recent developments in the tribological potentials of 2D materials. At first, the essential physical, wear, and frictional characteristics of the 2D materials including their production techniques are discussed. Subsequently, the experimental explorations and theoretical simulations of the most common 2D materials are reviewed in regards to their tribological applications such as their use as solid lubricants and surface lubricant nano-additives. The effects of micro/nano textures on friction behavior are also reviewed. Finally, the current challenges in tribological applications of 2D materials and their prospects are discussed.

We present software on total energy calculation by quantum mechanics first principle method with a graphic user interface (GUI). Total energy calculation in this software is based on numerical analysis of time-dependent density functional (the used numerical method is finite difference time domain). QUMEC package has been equipped by common exchange-correlation energy terms with electron spin polarization calculation. With this package, users can calculate the total energy of the free particle, bulk materials, and materials with free surfaces at the atomic scale. The package is tested by several physical subjects, i.e., the surface energy of nano-LiCoO₂ and diffusion constant of lithium atoms in LiNi­_0.5Mn_1.5O₄.

The direct growth of single-walled carbon nanotubes (SWCNTs) with a narrow distribution of diameter or chirality remains elusive despite significant benefits in properties and applications. Nanoparticle catalysts are vital for SWCNT synthesis, but how to precisely manipulate their chemistry, size, concentration, and deposition remains difficult, especially within a continuous production process from the gas-phase. Here, we demonstrate the preparation of W6Co7 alloyed nanoparticle catalysts with precisely tunable stoichiometry using electrospray, which remain solid state during SWCNT growth. We also demonstrate continuous production of liquid iron nanoparticles with in-line size selection. With the precise size manipulation of catalysts in the range of 1-5 nm, and a nearly monodisperse distribution (σ_g < 1.2), an excellent size selection of SWCNT can be achieved. All of the presented techniques show great potential to facilitate the realization of single-chirality SWCNT production.

The use of cow bones for biomaterial is still limited; accordingly, the cow bones waste has low economic value. Basically, a human’s and a cow’s bones are the same in terms of their forming compound. Aluminum (Al) has the potential to combine with hydroxyapatite (HAp) to make metal matrix composites (MMC) that have the potential for biomaterials. Compatible elements to be combined with Al and HAp are magnesium (Mg), titanium (Ti), and Copper (Cu), used self-high propagating temperatures synthesis (SHS). MMC can be processed to be a useful, solid product. Applying pressure to the SHS reaction and heating process may result in biomaterial composite product consisting of some matrix materials such as Al come from cans materials used in the experiment was HAp that was processed from cow bones calcination, added by can that contained aluminum and wetting agent, namely magnesium. The exothermic temperature was 800-900°C. The compaction process was done to allow materials to be bound. Based on the ASTM F138 standard for element of biomaterials, the porosity value was below 30% and hardness level above 40 HV. Cow bones and can-based composite sample with the composition of HAp-Al-Mg: 85%-10%-5% met the standard since the hardness value was: 73.3 HV with a porosity value of 29.88%.

The universal Debye – Mayer – Kelly hybrid model was proposed for the description of the heat capacity from 0 K to the melting points of substance within the experimental uncertainty for the first time. To describe the heat capacity, the in-house software on the base of commercial one DELPHI-7 was used with a 95% confidence level. To demonstrate the perfect suitability of this model, a thermodynamic analysis of the heat capacities of the fourth group elements, and some compounds of the A^IIIB^V and A^IIB^VI phases was carried out. It produced good agreement within the experimental uncertainty. There is no a similar model description in literature.The Similarity Method is a convenient and effective tool for critical analysis of the heat capacities of isostructural phases, which was used as an example for diamond-like compounds. Phases with the same sum of the atomic numbers of elements (Z), such as diamond and B_0.5 N_{0.5 (cub)} (Z = 6); pure silicon (Si) and Al_0.5 P_0.5 (Z=14); pure germanium (Ge) and Ga_0.5 As_0.5 (Z = 32)); pure grey tin (alpha-Sn) and In_0.5 Sb_0.5, and Cd_0.5 Te_0.5 (Z = 50) have the same heat capacity experimental values in the solid state. The proposed models can be used to both different binary and multicomponent phases. It helps to standardize the physicochemical constants.

The electronic structure and some of its derived properties of Li2CaGeO4 compound have been investigated. The calculations have been performed using the full-potential linearized augmented plane wave plus local orbitals method and ultra-soft pseudo-potentials . The optimized lattice parameters are found to be ingood accord with experiment. Features such as bulk modulus and its pressure derivative, electronic band structure and density of states are reported. The elastic anisotropy of the crystal is discussed and visualized. Moreover, the optical properties reveal that Li2CaGeO4 compound are suitable candidates for optoelectronic devices in the visible and ultraviolet (UV) regions.

A super-porous hybrid platform can offer significantly increased number of reaction sites for the analytes and thus can offer advantages in the biosensor applications. In this work, a significantly improved sensitivity and selectivity of hydrogen peroxide (H2O2) cancer sensor is demonstrated by a super-porous hybrid CuO/Pt NP platform. The super-porous hybrid platform is fabricated by a physiochemical approach combining the physical vapor deposition of Pt NPs and electrochemical deposition of super-porous CuO structures by adopting a dynamic hydrogen bubble technique. Under an optimized condition, the hybrid CuO/Pt biosensor demonstrates a very high sensitivity of 2,205 µA/mM∙cm2 and a low limit of detection (LOD) of 140 nM with a wide range of H2O2 detection. This is meaningfully improved performance as compared to the CuO-based H2O2 sensors as well as to the previously reported metal oxide based H2O2 sensors. The hybrid CuO/Pt platform exhibits excellent selectivity against other interfering molecules such as glucose, fructose, dopamine, and ascorbic acid. Due to the synergetic effect of highly porous CuO structures and underlying Pt NPs, the CuO/Pt architecture offers extremely abundant active sites for the H2O2 reduction and electron transfer pathways.

A theoretical nonlocal thermoelastic model for studying the effects of the thermal conductivity variability on a rotating nanobeam has been described in the present article. The theory of thermal stress is employed using the Euler–Bernoulli beam model and generalized heat conduction with phase lags. It is believed that the thermal conductivity of the current model varies linearly according to temperature. Due to variable harmonic heat, the considered nanobeam excited and was subjected to a time-varying exponential decay load. Using the Laplace transform process, the analytical solutions for displacement, deflection, thermodynamic temperature and bending moment of rotating nanobeams are provided in final forms and a numerical example has been taken to address the problem. A comparison of the stated results was displayed and additionally, the influences of non-local parameters and varying load were analyzed and examined. We also investigate how the linear changes in the temperature of physical properties can influence both the static and dynamic responses to the rotating nanobeam.

Graphite nanoplatelets (GNPs) were produced from flake graphite that had been immersed in isopropyl alcohol solution (70%) and converted to powder form in an ultrasonic bath (5 h, room temperature). Scanning and transmission electron microscopy, X-ray diffractometry, and Raman spectroscopy identified 120-nm-thick GNP crystallites and 0.5–21 µm plates with different areas and shapes. Extensive exfoliation was observed by transmission electron microscopy with abundant multilayer and some monolayer GNPs. X-ray diffractometry confirmed 43 GNP layers along the c-axis. Raman spectroscopy indicated well-defined GNPs with few defects and no oxide content. Rietveld analysis indicated a GNP crystal lattice with stacks of parallel two-dimensional graphene layers and tightly bound hybridized carbon atoms stacked in a translational …ABAB… sequence in hexagonal rings.

The development of a highly specific drug delivery system (DDS) for anti-cancer therapeutics is an area of intense research focus. Chemical engineering of a “smart” DDS to specifically target tumor cells has gained interest, designed for safer, more efficient, and effective use of chemotherapeutics for the treatment of cancer. However, the selective targeting and choosing the critical cancer surface biomarker are essential for targeted treatments to work. The folic acid receptor alpha (FRalpha) has gained popularity as a potential target in triple-negative breast cancer (TNBC). We have previously reported on a functionalized folic acid (FA)-conjugated amphiphilic alternating copolymer poly(styrene-alt-maleic anhydride) (FA-DABA-SMA) via a biodegradable linker 2,4-diaminobutyric acid (DABA) that has the essential features for efficient “smart” DDS. This biocompatible DDS self-assembles in a pH-dependent manner, providing stimuli-responsive, active targeting, extended-release of hydrophobic chemotherapeutic agents, and can effectively penetrate the inner core of 3-dimensional cancer spheroid models. The empty FA-DABA-SMA decreased spheroid volume, revealing a previously unknown mechanism of action. Upon further investigation, a size- and shape-dependent interaction FA-DABA-SMA with FR reduced the expression of p53, the product of the highly mutated TP53 gene, and additional oncogenic c-Myc and STAT3 proteins. Here, we investigated how this copolymer influences FR behavior and disrupting the receptor’s functions. Results indicate that FA-DABA-SMA increases FR expression levels in breast MDA MB-231 cancer cells and disrupting FR signaling by the reduction in HES1 and NOTCH1 protein expression levels. Also, FA-DABA-SMA induces apoptosis and further causes a change in the morphology of the MDA MB-231 cells, as well as significantly reduces their ability to migrate in a Scratch wound assay. Collectively, these findings provide a novel insight into the functionalized FA-DABA-SMA copolymer. The 350 kDa and 20 kDa copolymers actively target FRα to initialize internationalization. However, only the large size and sheet-shaped 350 kDa copolymers disrupt FRα signaling. The significance of these novel findings reveals the intracellular activity of the copolymer that is critically dependent on the size and structural shape. This report offers novel therapeutic insight into a dual mechanism of FA-DABA-SMA copolymer for its therapeutic potential for the treatment of cancer.

We report herein high-resolution x-ray diffraction measurements of basal plane bending of homoepitaxial single-crystal diamond (SCD). The results reveal that growth parameters such as temperature, growth time and basal plane bending of the substrate affect the basal plane bending of SCD. First, the basal plane bending of SCD depends mainly on the substrate itself. The basal plane bending of SCD becomes more severe with increasing basal plane bending of the substrate and this type of basal plane bending cannot be recovered. The SCD growth experiments show that the basal plane bending increases at high temperature and with increasing growth time. Finally, to understand the mechanism behind basal plane bending, we investigate the substrate-surface temperature distribution as a function of basal plane bending of SCD fabricated by chemical vapour deposition (CVD). This allows us to propose a bending model and understand the origin of basal plane bending. The results indicate that an uneven temperature distribution on the substrate surface is the main cause of the CVD diamond base-plane bending.

Single nanowires (NWs) are of great importance for various optoelectronic applications, especially solar cells serving as powering nanoscale devices. However, weak off-resonant absorption can limit its light-harvesting capability. Here, we propose a single NW coated with the graded-index dual shells (DSNW). We demonstrate that with the proper thickness and refractive index of the inner shell, the DSNW exhibits significantly enhanced light trapping compared with the bare NW (BNW), and the NW only coated with the outer shell (OSNW) and inner shell (ISNW), which can be attributed to the optimal off-resonant absorption mode profiles due to the improved coupling between the reemitted light of the leak mode resonances of the Si core and the nanofocusing light from the dual shells with the graded refractive index. We found that the light absorption can be adjusted via tuning the thickness and refractive index of the inner shell, the photocurrent density is significantly enhanced by 134% (56%, 12%) in comparison with that of the BNW (OSNW, ISNW). This work advances our understanding of how to improve off-resonant absorption by applying graded dual shells and provides a new choice for designing high-efficiency single NW photovoltaic devices.

Thermal interface material (TIM) that can exist as liquid at the service temperature enables efficient heat transfer across two adjacent surfaces in electronic applications. In this work, the thermal conductivities of different phase regions in the Ga-In system at various compositions and temperatures are measured for the first time. A modified comparative cut bar technique is used for the measurement of the thermal conductivities of In_xGa_1-x (x=0, 0.1, 0.214, 0.3, and 0.9) alloys at 40, 60, 80, and 100^oC that are the temperatures commonly encountered in consumer electronics. The thermal conductivity values for the liquid and semi-liquid (liquid+β) Ga-In alloys are higher than the TIM currently used in consumer electronics. These measured quantities, along with the available experimental data from the literature, served as input for the thermal conductivity parameter optimization using the CALPHAD (CALculation of PHase Diagram) method for the pure elements, solution phase, and two-phase region. A set of self-consistent parameters for the description of the thermal conductivity of the Ga-In system is obtained. There is good agreement between the measured and calculated thermal conductivity values for all the phases. Hence, it can be envisaged that liquid/semi-liquid Ga-In alloys can be considered as a potential TIM in consumer electronics due to its high thermal conductivity.

We prepared heterogeneous alumina-silicate glasses by consolidating nanoparticles using molecular dynamics simulations. Consolidated glasses from either low alumina content alumina-silicate glasses or high alumina content alumina-silicate glasses show significantly improved ductility around consolidation pressure of ~3 GPa. The introduced structural heterogeneities, namely over-coordinated network formers and their neighboring oxygen atoms, are identified as plasticity carriers due to their high rearrangement propensity. In addition, consolidated oxide glass from both 23.4Al₂O₃76.6SiO₂ and 73.1Al₂O₃26.9SiO₂ nanoparticles show improved flow strength (up to 1 GPa) due to the introduction of chemical heterogeneities. Last but not least, apparent hardening behavior appears upon cold work in consolidated glasses, with an increase of yield strength from ~3.3 GPa to ~6.4 GPa. This method is a big advancement toward ultra-strong and ultra-tough glasses by breaking the structure, composition and size limitations in traditional melt-quench process.

Biological gels (bio-gels) are hydrated polymer networks that serve diverse biological functions, which often lead to intentional or unintentional exposure to particulate matter. In this work, we derive a microscopically motivated framework that enables the investigation of penetration mechanisms into bio-gels. We distinguish between two types of mechanisms: spontaneous (unforced) penetration and forced penetration. Using experimental data available in literature, we exploit the proposed model to characterize and compare between the micro-structures of respiratory, intestinal, and cervicovaginal mucus and two types of biofilms. Next, we investigate the forced penetration process of spherical and ellipsoidal particles into a locally quadrilateral network. The proposed framework can be used to improve and complement the analysis of experimental findings in vitro, ex vivo, and in vivo. Additionally, the insights from this work pave the way towards enhanced designs of nano-medicines and allow to assess risk factors related to the nano-pollutants exposure.

Intranasal (i.n.) administration became an alternative strategy to bypass the blood-brain barrier and improve drug bioavailability in the brain. The main goal of this work was to preliminarily study the biodistribution of mixed amphiphilic mucoadhesive nanoparticles made of chitosan-g-poly(methyl methacrylate) and poly(vinyl alcohol)-g-poly(methyl methacrylate) and ionotropically crosslinked with sodium tripolyphosphate in the brain after intravenous (i.v.) and i.n. administration to Hsd:ICR mice. After i.v. administration, the highest nanoparticle accumulation was detected in the liver, among other peripheral organs. After i.n. administration of a 10-times smaller nanoparticle dose, the accumulation of the nanoparticles in off-target organs was much lower than after i.v. injection. In particular, the accumulation of the nanoparticles in the liver was 20 times lower than by i.v. When brains were analyzed separately, intravenously administered nanoparticles accumulated mainly in the “top” brain, reaching a maximum after 1h. Conversely, in i.n. administration, nanoparticles were detected in the “bottom” brain and the head (maximum reached after 2 h) owing to their retention in the nasal mucosa and could serve as a reservoir from which the drug is released and transported to the brain over time. Overall results indicate that i.n. nanoparticles reach similar brain bioavailability, though with a 10-fold smaller dose, and accumulate in off-target organs to a more limited extent and only after redistribution through the systemic circulation. At the same time, both administration routes seem to lead to differential accumulation in brain regions and thus, they could be beneficial in the treatment of different medical conditions.

Hemoconcentration membranes used in cardiopulmonary bypass require a pore structure design with high pure water permeability, and which does not allow protein adsorption and useful protein loss. However, studies on hemoconcentration membranes have not been conducted yet. The purpose of this study was to analyze three-dimensional pore structures and protein fouling before and after blood contact with capillary membranes using the tortuous pore diffusion model and a scanning probe microscope system. We examined two commercially available capillary membranes of similar polymer composition that are successfully used in hemoconcentration clinically. Assuming the conditions of actual use in cardiopulmonary bypass, we perfused these membranes with bovine blood. Pure water permeability before and after bovine blood perfusion was measured using the dead-end filtration. The scanning probe microscopy system was used for analysis. High-resolution three-dimensional pore structures on the inner surface of the membranes were observed before blood contact. On the other hand, pore structures after blood contact could not be observed due to protein fouling. The pore diameters calculated by the tortuous pore diffusion model and scanning probe microscopy were mostly similar and could be validated reciprocally. Achievable pure water permeabilities showed no difference despite protein fouling, leading to low values of albumin SC. This is due to the mechanism that protein fouling occurs on the membrane surface, while there is little internal pore blocking. Therefore, controlling the fouling is essential for membranes in medical use. These characteristics of the hemoconcentration membranes examined in this study are suitable for clinical use.

Knowledge about the formation energies of compounds is essential to derive phase diagrams of multi-component phases with respect to elemental reservoirs. The determination of formation energies using common (semi-)local exchange-correlation approximations of density functional theory (DFT) exhibits well-known systematic errors if applied to oxide compounds containing transition metal elements. In this work, we generalize, reevaluate and discuss a set of approaches proposed and widely applied in the literature to correct for errors arising from the over-binding of the O2 molecule and from correlation effects of electrons in localized transition-metal orbitals. The DFT+U method is exemplarily applied to iron oxide compounds, and a procedure is presented to obtain U values, which lead to formation energies and electronic band gaps comparable to experimental values. Using such corrected formation energies, we derive the phase diagrams for LaFeO3, Li5FeO4 and NaFeO2, which are promising materials for energy conversion and storage devices. A scheme is presented to transform the variables of the phase diagrams from the chemical potentials of elemental phases to those of precursor compounds of a solid-state reaction, which represents the experimental synthesis process more appropriately. The discussed workflow of methods can directly be applied to other transition metal oxides.

Oleylamine capped WS2 nanostructures were successfully formed at 320 °C via a relatively simple colloidal route. SEM and TEM analyses showed that the 3D nanoflowers that were initially formed disintegrated into 2D nanosheets after prolonged incubation. XPS and XRD analyses confirmed oxidation of WS2 into WO3. Sensors based on these oleylamine capped WS2 nanoflowers and nanosheets still showed a change in electrical response towards various concentrations of NH3 vapour at room temperature in a 25% relative humidity background despite the oxidation. The nanoflowers exhibited n-type response while the nanosheets displayed a p-type response towards NH3 exposure. The nanoflower based sensors showed better response to NH3 vapour exposure than the nanosheets. The sensors showed a good selectivity towards NH3 relative to acetone, ethanol, chloroform and toluene. Meanwhile, a strong interference of humidity to the NH3 response was displayed at high relative humidity levels. The results demonstrated that oleylamine limited the extent of oxidation of WS2 nanostructures. The superior sensing performance of the nanoflowers can be attributed to their hierarchical morphology which enhances the surface area and diffusion of the analyte.

Raindrop erosion is a significant materials limiting issue. It can affect materials for transportation and renewable energy converters such as wind turbines as well as all external structures used in the construction industries. In such cases, the raindrop effects can occur over a wide range of impact velocities and particles sizes. In understanding tribological variable effects, it is useful to study using reference materials. This is because the reference material is well characterized, from previous knowledge of the tribological and corrosion patterns. Further, the well established chemical composition and stochiometry of the corrosion products provide some background understanding of how effectively, during tribological action, the surface scale adheres to the substrate. In this study, a carbon steel was used as a reference to study the effects of velocity and drop diameter in a whirling arm erosion test rig. The results were used to establish the conditions where corrosion was accelerated and the environments where aerodynamic effects may have resulted in droplets being deflected the surfaces. Erosion maps were generated to illustrate such mechanisms based on the results.

Raindrop erosion is a significant materials limiting issue. It can affect materials for transportation and renewable energy converters such as wind turbines as well as all external structures used in the construction industries. In such cases, the raindrop effects can occur over a wide range of impact velocities and particles sizes. In understanding tribological variable effects, it is useful to study using reference materials. This is because the reference material is well characterized, from previous knowledge of the tribological and corrosion patterns. Further, the well established chemical composition and stochiometry of the corrosion products provide some background understanding of how effectively, during tribological action, the surface scale adheres to the substrate. In this study, a carbon steel was used as a reference to study the effects of velocity and drop diameter in a whirling arm erosion test rig. The results were used to establish the conditions where corrosion was accelerated and the environments where aerodynamic effects may have resulted in droplets being deflected the surfaces. Erosion maps were generated to illustrate such mechanisms based on the results.

The results of the bibliographic analysis show that the most explored nanomaterials in dentistry are graphene and carbon nanotubes, and their derivatives. A detailed analysis and a comparative study on their applications show that, although they are quite similar, graphene based materials seem to be more promising for most of the applications of interest in dentistry. The bibliographic study also demonstrated the potential of zeolite based materials, although the low number of studies on their applications shows that they have not been totally explored, as well as other porous nanomaterials that found important applications in medicine, such as metal organic frameworks, have not been explored. Subsequently, it is expected that the research effort will concentrate in graphene and zeolite based materials in the incoming years. Thus, present review paper presents a detailed bibliographic study, with more than 200 references, in order to describe briefly the main achievements that have been described in dentistry using nanomaterials, compare and analyze them in a critical way, with the aim of predicting the future challenges.

The selection of biomaterials for biomedical application is a significant challenge. In the last few decades, various bioabsorbable and stable biopolymers have been applied for use as biomedical devices in orthopedic applications. Ultra-high molecular weight polyethylene (UHMWPE) has been extensively used in medical implants, notably in the bearings of hip, knee, and other joint prostheses, owing to its biocompatibility and high wear resistance. For the ACL graft, synthetic UHMWPE is an ideal candidate due to its biocompatibility and its extremely high tensile strength. Despite the appeal of new advanced materials such as carbon fiber, poly-ether-ether ketone, and other load-bearing materials, UHMWPE remains a primary load-bearing candidate material for ACL reconstructions because of its extremely high strength, the simplicity of the fabrication process, its biocompatibility, and low friction. However, some significant problems are observed in UHMWPE based implants, such as wear debris, and oxidative degradation due to the generation of free radicals when exposed to irradiation with gamma rays for grafting or sterilization. Various innovative methodologies have been developed to resolve those problems and enhance the properties of UHMWPE. In this review, we will explore in detail the methods for surface functionalization of UHMWPE and will apply these findings to the case study of UHMWPE for Anterior Cruciate Ligament repair.

In this study, the hot deformation of Cu-0.55Sn-0.08La (wt%) alloy was studied by gleeble-3180 testing machine at deformation temperatures of 400-700oC and various strain rates. The stress-strain curve showed that the hot deformation behavior of Cu-0.55Sn-0.08La (wt%) alloy was greatly affected by work hardening, dynamic recovery, and dynamic recrystallization. The activation energy Q was calculated as 287.141 kJ/mol , and hot compression constitutive equation was determined as ε ̇=[sinh(0.006388σ)]^12.123∙exp⁡(37.7505-287.141/RT). The microstructural evolution of the alloy during deformation at 400oC revealed the presence of both slip and shear bands in the grains. At 700oC, dynamic recrystallization grains were observed but recrystallization was incomplete. In sum, these results provided the theoretical basis for continuous extrusion process of alloys with promising future use.

The TiO₂ nanostructures resulted by pyrolysis of TiCl₄ at low temperature of 80 ^oC are found to be a mixture of amorphous TiO₂ complexes and anatase nanostructure that depends on the pH of the pyrolysis medium. Anatase nanostructure is predominant at low pH level and gradually converts to amorphous TiO₂ complexes with increasing pH level. By means of heat treatment, the TiO₂ nanostructures can be recovered from amorphous TiO₂ complexes. Amongst of the TiO₂ nanostructure recovered from amorphous TiO₂ complexes, the anatase nanostructure shows to be the strongest photocatalyst in decomposition of methylene blue.

Metal additive manufacturing (AM) has gained much attentions in recent years due to its advantages including geometric freedom and design complexity, appropriate to a wide range of potential industrial applications. However, conventional metal AM methods have high-cost barriers due to the initial cost of the capital equipment, support and maintenance, etc. This study presents a unique low-cost metal material extrusion (MME) technology. The filaments used have polylactic acid (PLA) as the matrix and metal powders (copper, bronze, stainless steel, high carbon iron, and aluminum) as reinforcements. Using the proposed fabrication technology, test specimens were built by extruding polymer/metal composite filaments, which were then sintered in an open-air furnace to produce solid metallic parts. In this research, the mechanical and thermal properties of the built parts are examined using tensile tests, thermogravimetric-, thermomechanical- and microstructural analysis.

Understanding potential uptake and biodistribution of engineered nanoparticles in soil-grown plants is imperative for toxicity and risk assessment considering the oral exposure of edibles by humans. Herein, we assessed potential influence of particle size (25, 50, and 250 nm) and concentration (0, 50, 100, 200, and 500 mg/kg-soil) of Copper oxide nanoparticles (CuONPs) on: (1) the root system architecture, and the physicochemical attributes of soil at the soil-root interface, (2) leading to Cu transport and accumulation in root, stem, leaf and seed in soybean (Glycine max cv Kowsar) grown for entire lifecycle of 120 days, and compared with soluble Cu²⁺ ions and water-only controls, and (3) performed a comparative assessment of total seed Cu levels in soybean with other valuable food sources for Cu intake and discussed its human health implications. Our findings showed particle size- and concentration-dependent influence of CuONPs on Cu uptake and tissue distribution in root, stem, leaf and seed in soybean. Alterations in root architecture (root dry weight, root length, root volume, and root area) were dependent on the Cu compound type, Cu concentrations, and their interactions (p<0.05), except for root density. Concentration-response relationships for all three sized CuONPs, and Cu²⁺ ions, were linear. CuONPs and Cu²⁺ ions had inhibitory effects on root growth and development. Overall, soybean responses to smallest size CuONPs-25 nm were higher for all parameters investigated compared to two larger sized CuONPs (50 nm, 250 nm) or Cu²⁺ ions. Cu uptake/bioaccumulation differed among soybean tissues in the order: root > leaf > stem > seed. Despite reduced root architecture and seed yield, our smallest size CuONPs-25 nm led to increased total seed Cu uptake compared to the larger sized CuONPs and Cu²⁺ ions tested. Our findings also suggest that soil amendment by CuONPs, more so by the smallest size CuONPs-25 nm, could significantly improve nutritional Cu value in soybean seed as reflected by % Daily Values (DV), and are rated “Good” to “Very Good” according to the “World’s Healthiest Foods” rating. However, until the potential toxicity and risk from consumption of soybean seed is characterized in humans, caution should be exercised when the Cu fortified seeds are used for daily human consumption when addressing Cu deficiency and associated illnesses, globally.

Dentin bonding is a key in restorative dentistry. Herein, we developed self-etching two-bottle adhesive system containing 10-methacryloyloxidecyl dihydrogen phosphate monomer (MDP) and the physical, mechanical, and biocompatible properties were evaluated. The characteristics of MDP were analyzed using nuclear magnetic resonance (NMR). The water sorption and solubility, the shear-bond strengths to dentin and enamel, and cytotoxicity tests were performed. The newly blended experimental group showed the lowest thickness and water sorption and solubility values. The shear bond strength to enamel and dentin were comparable to control groups (the three other products) all test groups showed 60% of cell viability. In this study, the properties of the newly synthesized adhesive are comparable with the others. The fundamental goal of this study is to get the MDP patent released, as it is intended for domestic production. For this purpose, this dentin adhesive was developed and compared with the commercial product.

This study explores the potential to reach a circular economy for post-consumer recycled polyethylene terephthalate (rPET) packaging and bottles by using it as a distributed recycling for additive manufacturing (DRAM) feedstock. Specifically, rPET is processed using only an open source toolchain with fused particle fabrication (FPF) or fused granular fabrication (FGF) processing. In this study, first the impact of granulation, sifting and heating (and their combination) is quantified on the shape and size distribution of the rPET flakes. Then feeding studies were performed to see if they could be printed through an external feeder or needed to be direct printed with a hopper using two Gigabot X machines, one with extended part cooling and one without. Print settings were optimized based on thermal characterization and for the latter which was shown to print rPET directly from shredded water bottles mechanical testing is performed. The results showed that geometry was important for extended feeding tubes and direct printed using a hopper. Further there is a wide disparity in the physical properties of rPET from water bottles depending on source and the history of the material. Future work is needed to enable water bottles to be used as a widespread DRAM feedstock.

Several coatings configurations of combined aluminizing and diffusion layered aluminide on 316 steel were produced and characterized. These coatings, typically employed as thermal barrier coating (TBC), can also be effective as vibration reduction elements at intermediate and high temperatures. This preliminary work has been focused on the microstructural design and processing effects of the coatings. The damping of the produced specimens was measured up to 450°C and compared with that of the steel substrate. The most performing coatings contain an Al-Si layer and exhibit a steep damping increase above 200 °C, reasonably due to dislocation movements by plastic straining of soft alloy layer and to the interface sliding between layers with different elastic moduli.

Recent years brought great focus in the field of development of extracellular vesicles (EVs) based drug-delivery systems. Considering possible applications of EVs as a drug carriers the isolation process is a crucial step. To solve problems related with EV isolation, we created and validated a new EVs isolation method – Low Vacuum Filtration (LVF) and compared it with two commonly applied procedures - differential centrifugation (DC) and ultracentrifugation (UC). EVs isolated from endothelial cells culture media have been characterized by a) transmission electron microscopy (TEM) b) nanoparticle tracking analysis (NTA), c) western blot and d) Fourier-Transform Infrared Spectroscopy (FTIR). Additionally, the membrane surface have been imaged with Environmental Scanning Electron Microscopy (ESEM). We showed that LVF is reproducible and efficient method for EVs isolation form conditioned media. Additionally, we observed correlation between ATR-FTIR spectra quality and the EVs and proteins concentration. ESEM imaging confirmed that actual pore diameter are close to the values calculated theoretically. LVF method is an easy, fast and inexpensive EVs isolation method which allows for isolation of both ectosomes and exosomes from high volume sources with good repeatability. We think that it could be an efficient alternative for commonly applied methods.

Here we report the effect of substrate, sonication process, and post-annealing on the structural, morphological, and optical properties of ZnO thin films grown in presence of isopropyl alcohol (IPA) at temperature 30 – 65 ℃ by SILAR method on both soda lime glass (SLG) and Cu foil. The X-ray diffraction (XRD) patterns confirmed the preferential growth of ZnO thin films along (002) and (101) plane while grown on SLG and Cu foil substrate respectively. Both XRD and Raman spectra confirmed the ZnO and Cu-oxide phases of the deposited films. Scanning electron microscope (SEM) image of the deposited films shows compact and uniformly distributed grains for samples grown without sonication while using IPA at temperature 50 and 65 ℃. The post-annealing treatment improves the crystallinity of the films, further evident by XRD and UV-VIS-NIR results. The estimated optical bandgaps are in the range of 3.37-3.48 eV for as-made samples. Results revealed that high-quality ZnO thin films could be grown without sonication using IPA dispersant at 50 ℃, which is much lower than the reported results using the SILAR method. This study suggests that in the presence of IPA, the SLG substrate results in better c-axis oriented ZnO thin films than that of DI water, ethylene glycol, propylene glycol at the optimum temperature of 50 ℃. Air-annealing of the samples grown on Cu foils induced the formation of CuxO/ZnO junctions which is evident from the characteristic I-V curve including the structural and optical data.

In this work, the structural, magnetic, and mechanical properties of Nd16Fe76-xCoxB8 alloys varying the Co content at x = 0, 10, 20 and 25, were experimentally investigated by X-Ray Diffraction (XRD), Mössbauer Spectrometry (MS), Vibrating Sample Magnetometry (VSM) at room temperature (RT), and microhardness test were performed too. The system presents the hard Nd2Fe14B and the Nd1.1Fe4B4 phases for samples with x = 0 and 10. When concentration increases to x= 20 and 25, the CoO phase appears. All MS show the ferromagnetic behavior (eight sextets: sites 16k1, 16k2, 8j1, 8j2, 4c, 4e, sb) associated to the hard and soft magnetic phases, and one paramagnetic component (doublet: site d) associated to the minority Nd1.1Fe4B4 phase, which was not identified by XRD. All samples are magnetically hard present a hard magnetic behavior. The increase of Co content in these samples did not improve the hard magnetic behavior, but increased the critical temperature of the system and decrease the crystallite size of the hard phase. The hysteresis loop showed that predominates the Nd2Fe14B hard magnetic phase. There is a general tendency to increase microhardness with cobalt content, attributable to cobalt doping reduces the lattice parameters and porosities in the sample improving it hardness.

The study of co-fusion was one of the essential topics in the history of metallurgy in China. Simulation experiments had been an essential concept in the study of the co-fusion steelmaking process. This paper mainly studied the simulation experiments of co-fusion from two aspects: the replication of co-fusion swords by three different methods, and the micro-analysis of the co-fusion samples. The experimental results indicated that several co-fusion swords could be made by different processes, but the carbon content and surface hardness were quite different. During repeated forging welded, the microstructure of the samples transformed from laminated to homogenized, finally the steel with a uniform carbon content was obtained. It was challenging to find the characteristics of co-fusion from the homogenized samples. The results prompted people to rethink the microstructure characteristics of ancient co-fusion artifacts.

Aluminium alloys have evolved as suitable materials for automotive and aircraft industries due to their reduced weight, excellent fatigue properties, high-strength to weight ratio, high workability/formability, and corrosion resistance. Recently, the joining of similar and dissimilar metals have achieved huge success in various sectors. The processing of soft metals like aluminium, copper, iron and nickel have been fabricated using friction stir processing. Friction stir processing (FSP) is a microstructural modifying technique that uses the same principles as the friction stir welding technique. In the majority of studies on FSP, the effect of process parameters on the microstructure was characterized after a single pass. However, multiple passes of FSP is another method to further modify the microstructure in aluminium castings. This study is aimed at reviewing the impact of multi-pass friction stir processed joints of aluminium alloys and to identify a knowledge gap. From the literature that is available on multi-pass FSP, it has been observed that the majority of the literature focused on the processing of plates than the joints. There is limited literature reporting on multi-pass friction stir processed joints. This then creates a need to study further on multi-pass friction stir processing on dissimilar aluminium alloys.

Commercially available oxidized (carboxylic groups) and non-oxidized multiwalled carbon nanotubes were studied as adsorbents of cerium(III) in batch operation mode. Several variables affecting the rare earth adsorption were investigated, including: the stirring speed applied to the system, the pH of the solution and the metal concentration and carbon dosages. Although the removal of cerium from the solution is different and dependent upon the adsorbent type: i) adsorption in non-oxidized multiwalled carbon nanotubes, ii) cation exchange in the case of using oxidized multiwalled carbon nanotubes, the adsorption kinetics, the rate law and the isotherm models are the same for both adsorbents: pseudo-second order, film diffusion and Langmuir Type-1, respectively. Cerium is desorbed from loaded adsorbents using acidic solutions.

We report the negative effective mass metamaterials based on the electro-mechanical coupling exploiting plasma oscillations of a free electron gas. The negative mass appears as a result of vibration of a metallic particle with a frequency of ω which is close to the frequency of the plasma oscillations of the electron gas m_2 relatively to the ionic lattice m_1. The plasma oscillations are represented with the elastic spring k_2=ω_p^2 m_2, where ω_p is the plasma frequency. Thus, the metallic particle vibrated with the external frequency ω is described by the effective mass m_eff=m_1+(m_2 ω_p^2)/(ω_p^2-ω^2 ) , which is negative when the frequency ω approaches ω_p from above. The idea is exemplified with two conducting metals, namely Au and Li embedded into various matrices. The one-dimensional lattice built of the identical metallic micro-elements m_eff connected by ideal springs k_1 representing various media such as polydimethylsiloxane and soda-lime glass is treated. The optical and acoustical branches of longitudinal modes propagating through the lattice are elucidated for various ratios ω_1/ω_p . The 1D lattice built of the thin metallic wires giving rise to the low frequency plasmons is treated. The possibility of the anti-resonant propagation, strengthening the effect of the negative mass occurring under  = p = 1 is addressed.

The cellulose/GO networks as the scaffold of free-standing aerogel electrodes are developed by using lithium bromide aqueous solution as the solvent to ensure the complete dissolution of cotton linter pulp and well dispersion/reduction of GO nanosheets. PANI nanoclusters are then coated onto cellulose/GO networks via in-situ polymerization of aniline monomers. By optimized weight ratio of GO and PANI, the ternary cellulose/GO3.5/PANI aerogel film exhibits well-defined three-dimensional porous structures and high conductivity of 1.15 S/cm that contributes to its high areal specific capacitance of 1218 mF/cm2 at the current density of 1.0 mA/cm2. Utilizing this cellulose/GO3.5/PANI aerogel film as electrodes in a symmetric configuration supercapacitor can result in an outstanding energy density as high as 258.2 μWh/cm2 at a power density of 1201.4 μW/cm2. Moreover, the device can maintain nearly constant capacitance under different bending deformations, suggesting its promising applications in flexible electronics.

Air filtration mechanisms in the composite filter media used in practical applications are important and challenging to understand because the component fibers could have various size scales and morphologies. In this work, a three-dimensional digital model of nanofiber-based filter media was reconstructed for the first time based on the X-ray tomography data for the cellulose substrate and the Focused Ion Beam-Scanning Electron Microscope (FIB-SEM) image analysis for the several microns thick (3.82-7.90 μm) electrospun polyvinylidene fluoride (PVDF) nanofiber membrane. Besides the high-resolution model where the details of the fibrous structures were fully resolved, another low-resolution model with approximated unresolved structures was also established. Filtration simulations utilizing these models were conducted considering the drag force, Brownian diffusion and aerodynamic slip. The simulated filtration efficiencies agreed well with the experiments for particles of 70-400 nm, including the most penetrating particle size (MPPS, 100-200 nm). Moreover, the structure-resolved models had higher accuracy but higher computational costs, while the unresolved simulations saved much running time but over-predicted the filtration efficiency, especially for smaller particles (<100 nm). Our study presents a comprehensive strategy for investigating the composite filter media with multiscale complex structures using a combination of advanced characterization technologies and modular simulation models.

Background: Actually, resonance frequency analysis (RFA) is the most extended method for measuring implant stability. The implant stability quotient (ISQ) is the measure obtained by the different RFA devices, however, inter- and intra- rater reliability and validity of some devices remains unknown. Methods: Thirty implants were placed in 3 different pig mandibles. ISQ was measured axial and parallel with Osstell® Beacon, Penguin® and MegaISQ® by 2 different operators and one operator performed a test-retest. Intraclass correlation coefficient was calculated to assess the intra- and inter-rater reliability. Pearson correlation coefficient was used to assess the validity. Results: The higher inter- and intra- rater reliability was obtained by Penguin® when measuring axial. The highest ISQ values were obtained using Penguin® in an axial measurement; the lowest, using the MegaISQ® in an axial measurement. The highest correlation values with the other devices were obtained by MegaISQ® measuring axially. Conclusion: Penguin® had a good reliability for measuring ISQ both inter- and intra- rater. Osstell® had good validity for measuring ISQ both axial and parallel and MegaISQ® had the best validity for measuring ISQ axial.

Research on the chemical mechanism and reciprocal behavior of the coronavirus relate to living organisms, engaging in the give and take of electrochemical mediators, is a very important, controversial and vital issue. What we should accept is the chemical identity of this scenario, and not preferably a characteristic of a biological system. This chemical reaction should be familiar, referring to the theory of chemical pathways involved in DNA/proteins in the body against aggressive guests (such as viruses). From the point of view of a chemist, this simple reaction is nothing more than an oxidation-reduction reaction (redox-stress signaling) which conducted and carried out by coronavirus in a biointerface medium. Thereby, oxidizing as well as reducing reagents should be very constructive, promoting development in such chemical process. We understand redox reactions as switchable thiol/disulfide exchanges (formation and cleavage of inherent disulfide bonds), then, we can hugely profit from redox-responsive nano-surfaces equipped with multiple new ionic and covalent interactions. This game-changing idea can substantiate by surface modified-nanoparticles to play powerful roles in synthesis of nano oxidizers as well as reducing agents in nanomedicine. Chemists and pharmacists must then explore new thoughts and present modern experiences/approaches of preparation nanoparticles and nanocomposites to create novel vaccines as well as coronavirus drugs. In this regard, this experience can also be so helpful for HIV/AIDS, which is caused by viruses.

The unfolded band structure and optical properties of Cu-doped KCl crystals were computed by first principles within the framework of density functional theory, implemented in the ABINIT electronic structure package utilizing pseudopotential approximation and a plane-wave basis set. From a theoretical point of view, Cu substitution into pristine KCl crystals requires calculation by the supercell (SC) method. This procedure shrinks the Brillouin zone, resulting in a folded band structure that is difficult to interpret. To solve this problem and gain insight into the effect of copper ions (Cu+) on electronic properties, the band structure of SC KCl:Cu was unfolded to make a direct comparison with the band structure of the primitive cell (PC) of pristine KCl. To understand the effect of Cu substitution on optical absorption, we calculated the imaginary part of the dielectric function of KCl:Cu through a sum-over-states formalism and broke it down into different band contributions by partially making an iterated cumulative sum (ICS) of selected valence and conduction bands. Consequently, we identified those interband transitions that give rise to the absorption peaks due to the Cu+ ion. These transitions involve valence and conduction bands formed by the Cu-3d and Cu-4s electronic states

Inclusions in steels and alloys are known as factors that could lower deformation, mechanical, corrosion and other properties. Study of inclusions in nickel based alloys is important since these materials could suffer from corrosion degradation in harsh operational conditions, where inclusions could lead to a pitting initiation. For estimation of a harmful effect of different inclusions on corrosion resistance of Ni-based alloys, inclusion characteristics (such as composition, morphology, size, number and location) on film filter and dissolution of metal matrix around different inclusions on surfaces of metal samples after electrolytic extraction (EE) were investigated in two samples of industrial Ni-based alloys (alloy 718 and EP718). It was found that both Ni-based alloys have various inclusions: carbides (large size NbTi-C and small multicomponent carbides), nitrides TiNb-N and sulfides (TiNb-S in EP718 alloy). The higher harmful effect on corrosion resistance of metal was detected around sulfides and small carbides containing Mo, W, Cr. Dissolution effect was also observed around large carbides and nitrides, especially around inclusions having size more than 10 µm. Moreover, the dissolution of metal matrix around inclusions and clusters located on the grain boundaries is 2.1-2.7 times larger compared to that for those inclusions inside of grains of the given alloy samples.

The thermal properties of novel nanomaterials play a significant role in determining the performance of the material in technological applications. Herein, direct measurement of the temperature diffusivity of cellulose nanocomposite films was carried out by the micro-contact method. Polymer films containing up to 2%wt. of nanocellulose were synthesised by a simple chemical process. Films of a high optical transmittance T ≈ 80 % (for a 200- μ m-thick film), which were up to 44% crystalline, were characterised. Two different modalities of temperature diffusivity based on: 1) a resistance change and 2) micro-thermocouple detected modulation of a heat wave, were used for the polymer films with cross-sections of ∼ 100 μ m thickness. Twice different in-plane α ‖ and out-of-plane α ⊥ temperature diffusivities were directly determined with high fidelity: α ‖ = 2 . 12 × 10 − 7 m 2 /s and α ⊥ = 1 . 13 × 10 − 7 m 2 /s. An amorphous polyethylene terephthalate (PET) fiber was measured for comparison α ‖ = 1 . 15 × 10 − 7 m 2 /s. This work provides an example of a direct contact measurement of thermal properties of nanocellulose composite films. The thermal diffusivity, which is usually high in strongly interconnected networks and crystals, was investigated for the first time in this composite.

Optical and mechanical properties of multilayer coatings depend on the selected layer materials and the deposition technology; therefore, knowledge of the performances of thin films is essential. In the present work, titanium dioxide (TiO2) and silicon dioxide (SiO2) thin films have been prepared by plasma ion-assisted deposition (PIAD). The optical, structural, and mechanical properties of thin films have been investigated using spectrometer/ellipsometer, X-ray diffraction (XRD), atomic force microscopy (AFM), and laser interferometer. The results show that TiO2 film fabricated by PIAD induces a high refractive index, wide optical band gap, amorphous structure, smooth surface, and tensile stress. In the case of SiO2 film, high bias voltage leads to dense structure and compressive stress. As an application, a three-wavelength high reflectance at 632.8, 808, and 1550nm is optimized and deposited. The dependence of total stress in the multilayer on the substrate temperature is studied as well. In conclusion, it is demonstrated that PIAD is an effective method for the preparation of ultralow stress TiO2/SiO2 multilayer films. The achieved stress is as low as 1.4Mpa. The result could provide guidance to the stress optimization of most optical components without prefiguring, backside coating, and post-deposition treatments.

The cutting-edge photovoltaic cells are an indispensable part of the ongoing progress of earth-friendly plans for daily life energy consumption. However, the continuous electrical demand that extends to the night time requires a prior deployment of efficient real-time storage systems. In this regard, metal-air batteries have presented themselves as the most suitable candidates for solar energy storage, combining extra lightweight with higher power outputs and promises of longer life cycles. Scientific research over non-precious functional catalysts has always been the milestone and still contributing significantly to exploring new advanced materials and moderating the cost of both complementary technologies. Metal-organic frameworks (MOFs) derived functional materials have found their way to the application as storage and conversion materials, owing to their structural variety, porous advantages, as well as the tunability and high reactivity. In this review, we provide a detailed overview of the latest progress of MOF-based materials operating in metal-air batteries and photovoltaic cells.

The quantified residence time distribution (RTD) provides a numerical characterization of mixing in the continue casting tundish, thus allowing the engineer to better understand the metallurgical performance of the reactor. This paper describes a computational fluid dynamic (CFD) modelling study for analyzing the flow pattern and the residence time distribution in a five-strand tundish. Two passive scalar transport equations are applied to separately calculate the E-curve and F-curve in the tundish. The numerical modelling results are compared to the water modelling results for the validation of the mathematical model. The volume fraction of different flow regions (plug, mixed and dead) and the intermixing time during the ladle changeover are calculated to study the effects of the flow control device (FCD) on the tundish performance. The result shows that a combination of the U-baffle with deflector holes and the turbulence inhibitor has three major effects on the flow characteristics in the tundish: i) reduce the extent of the dead volume; ii) evenly distribute the liquid streams to each strand and iii) shorten the intermixing time during the ladle changeover operation.

Currently, metal nanoparticles have varied uses for different medical, pharmaceutical, and agricultural applications. Nano-biotechnology combined with green chemistry has great potential for the development of novel and necessary products that benefit human activities, while encourages the reduction of hazardous reagents for nanoparticle production. Green chemistry has an important role due to its contribution to unconventional synthesis methods of gold and silver nanoparticles from plant extracts, which have exhibited antimicrobial potential among other outstanding properties. Biodiversity-rich countries need to collect and convert knowledge from biological resources into processes, compounds, methods, and tools, which need to be achieved along with sustainable use and exploitation of biological diversity. Therefore, this review focuses on the importance of metal nanoparticles, the use of plant extract for their synthesis as well as other available methods, and the relevant antimicrobial activity that can be exploited in a sustainable model of agricultural management through a modern nanotechnological approach.

Water-soluble and cytocompatible polymers were investigated to enhance a transporting efficiency of biomolecules into cells in vitro. The polymers composed of 2-methacryloyloxyethyl phosphorylcholine (MPC) unit, a hydrophobic monomer unit, and a cationic monomer unit bearing an amino group were synthesized for complexation with model biomolecules, siRNA. The cationic MPC polymer was shown to interact with both siRNA and the cell membrane and was successively transported siRNA into cells. When introducing 20 − 50 mol% hydrophobic units into the cationic MPC polymer, transport of siRNA into cells. The MPC units (10 − 20 mol%) in the cationic MPC polymer were able to impart cytocompatibility, while maintaining interaction with siRNA and the cell membrane. The level of gene suppression of the siRNA/MPC polymer complex was evaluated in vitro and it was as the same level as that of a conventional siRNA transfection reagent, whereas its cytotoxicity was significantly lower. We concluded that these cytocompatible MPC polymers may be promising complexation reagent for introducing biomolecules into cells, with the potential to contribute to future fields of biotechnology, such as in vitro evaluation of gene functionality, and the production of engineered cells with biological functions.

With the decline in fossil fuels, hydrogen-based alternatives provide a reliable and clean source for sustainable energy generation. In these endeavors, photochemical splitting for hydrogen production through tandem cells has been the source of much theoretical and experimental research in science. Much focus has been placed on interfacial band gap engineering as one of the most promising routes in the generation of hydrogen.This present work explores sputtering of n-silicon to form the active electrode in a n-Si | n-TiO₂ tandem cell and investigates the effect of variations in sputtering and post sputtering treatment parameters (rapid thermal annealing and long cycle annealing) for successful deposition of crystalline Silicon. The samples were successfully characterized via Raman Spectroscopy, X-ray Diffraction and Optical Transmission Spectroscopy to ascertain prevalent crystalline order and optical band gap, under different sputtering and post-sputtering conditions. Relevant conclusions were drawn to ascertain the best possible deposition parameters of n-Si for photocatalytic water splitting.

Currently, the use of sustainable chemistry as an ecological alternative for the generation of products or processes, free of polluting substance has assumed a preponderant role. The aim of this work is propose a bioinspired, facile, at low cost, non-toxic and environmentally friendly alternative to obtaining magnetic nanoparticles whit a majority phase of magnetite (Fe₃O₄). Is important to empathize that the synthesis was based on the chemical reduction through the Cnicus Benedictus extract, whose use as reducing agent has not been reported in the synthesis of iron oxides nanoparticles. In addition, the Cnicus Benedictus is abundant endemic plant in Mexico, with several medicinal properties and a large number of natural antioxidants. The obtained nanoparticles exhibited significant magnetic and antibacterial properties and an enhanced photocatalytic activity. The crystallite size of the Fe₃O₄ nanoparticles (Fe₃O₄ NP’s) was calculated by Williamson-Hall method. The photocatalytic properties of the Fe₃O₄ NP´s were studied by kinetics absorptions models in the Congo red (CR) degradation. Finally the antibacterial effect of the Fe3O4 NP´s were evaluated mediated the Kirby-Bauer method against E. coli and S. aureus bacteria. This route offers a green alternative to obtain Fe3O4 NP´s with remarkable magnetic, photocatalytic and antibacterial properties.

Renewable nanocellulose materials received increased attention owing to their small dimensions, high specific surface area, high mechanical characteristics, biocompatibility, and compostability. Nanocellulose coatings are among many interesting applications of these materials to functionalize different by composition and structure surfaces, including plastics, polymer coatings, and textiles with broader applications from food packaging to smart textiles. Variations in porosity and thickness of nanocellulose coatings are used to adjust a load of functional molecules and particles into the coatings, their permeability, and filtration properties. Mechanical stability of nanocellulose coatings in a wet and dry state are critical characteristics for many applications. In this work, nanofibrillated and nanocrystalline cellulose coatings deposited on the surface of polymer films and textiles made of cellulose, polyester, and nylon are studied using atomic force microscopy, ellipsometry, and T-peel adhesion tests. Methods to improve coatings adhesion and stability using physical and chemical cross-linking with added polymers and polycarboxylic acids are analyzed in this study. The paper reports on the effect of the substrate structure and ability of nanocellulose particles to intercalate into the substrate on the coating adhesion.

For some decades, the scientific community has been looking for alternatives to the use of fossil fuels that allow the planet's sustainable and environmentally friendly development. To do this, attempts have been made to mimic some processes that occur in nature, among which the photosystem-II stands out, which allows water splitting operating with different steps to generate oxygen and hydrogen. This research presents promising results using synthetic catalysts, which try to simulate some natural processes, and which are based on [email protected]aphene compounds. These catalysts were prepared by incorporating different amounts of gold nanoparticles (1 wt.%, 3 wt.%, 5 wt.%, 10 wt.%) and graphene (1 wt.%) on the surface of synthesized zinc oxide nanowires (ZnO NWs), and zinc oxide nanoparticles (ZnO NPs), along with a commercial form (commercial ZnO) for comparison purposes. The highest amount of hydrogen (1,127 µmol/hg) was reported by ZnO NWs with a gold and graphene loadings of 10 wt.% and 1 wt.%, respectively, under irradiation at 400 nm. Quantities of 759 µmol / hg and 709 µmol / hg were obtained with catalysts based on ZnO NPs and commercial ZnO, respectively. The photocatalytic activity of all composites increased with respect to the bare semiconductors, being 2.5 times higher in ZnO NWs, 8.8 times for ZnO NPs and 7.5 times for commercial ZnO. The high photocatalytic activity of the catalysts is attributed, mainly, to the synergism between the different amount of gold and graphene incorporated, and the surface area of the composites.

The effect of retrogression re-aging treatment (RRA) on corrosion behavior of 7055 Al-Zn-Mg alloy were studied. Results provides the corrosion resistance could be greatly improved by RRA. After the RRA treatment, the isolated precipitates occurred on grain boundaries (GBs) and the low angle grain boundaries (LAGBs) presented a larger fraction compared to the single-stage peaking aging. The samples after RRA treatment also show better corrosion resistance than the single-stage peak aging. The results of electrochemical impedance spectroscopy (EIS) show that impedance spectrum is consisted of semi-infinite layer diffusion impedance and stagnant Weber impedance. The semi-infinite layer diffusion impedance corresponded a limited retention layer on the electrode surface. In corrosion process, Weber impedance corresponded to stagnant layer of corrosion products generated by the anode branches. The RRA sample has the high Rf and low Cf, Cp values, and the corrosion current density of the RRA samples is ten times less than the single-stage peak aging samples with the 10% hardness losing.

This work shows the results obtained in the synthesis of srilankite nanoparticles, (Zr, Ti)O2, and TiO2 anatase, both catalysts presented an admix of phases, anatase/rutile, and srilankite/rutile, respectively. Their performance in the production of biodiesel through the esterification of oleic acid was evaluated. The catalysts were obtained using the sol-gel process and sulfated via the impregnation method. The samples were characterized using X-ray diffraction (XRD), scan electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS) and Fourier-Transform Infrared Spectroscopy (FTIR) to analyze the properties in its crystalline structure, morphology, and chemical composition. Its efficiency during the esterification reaction was measured based on the decrease in free fatty acids (FFA). FFA, oleic acid was added at different weight percentages (1%, 3%, and 5% w/w). The time of reaction was 6 hours at 55 °C and the catalyst with better performance was the sulfated Srilankite/rutile, reaching a maximum conversion of up to 90%.

Chemical versatility of organic semiconductors provides nearly unlimited opportunities for tuning their electronic properties. However, despite decades of research, relationship between molecular structure, molecular packing and charge mobility in these materials remains poorly understood. This reduces the search for high-mobility organic semiconductors to the inefficient trial-and-error approach. For clarifying the abovementioned relationship, investigations of the effect of small changes in the chemical structure on OSs properties are particularly important. In this study, we address computationally the impact of substitution of C-H atom pairs by nitrogen atoms (N-substitution) on molecular properties, molecular packing and charge mobility of crystalline oligoacenes. Besides of decreasing frontier molecular orbital levels, N-substitution dramatically alters molecular electrostatic potential yielding pronounced electron-rich and electron-deficient areas. These changes in the molecular electrostatic potential strengthen face-to-face and edge-to-edge interactions in the corresponding crystals and result in the crossover from the herringbone packing motif to π-stacking. When the electron-rich and electron-deficient areas are large, sharply defined and, probably, have certain symmetry, charge mobility increases up to 3-4 cm2V-1s-1. The results obtained highlight the potential of azaacenes for application in organic electronic devices and are expected to facilitate rational design of organic semiconductors for steady improvement of organic electronics.

Herein we report on the use of different metal precursors in the synthesis of MoSe2 nanomaterials in order to control their morphology. The use of Mo(CO)6 as the metal precursor resulted in the formation of wrinkled few-layer nanosheets, while the use of H2MoO4 as the metal precursor resulted in the formation of nanoflowers. To investigate the effect of the morphologies on their performance as catalysts in the hydrogen evolution reaction, electrochemical characterization was done using linear sweep voltammetry, cyclic voltammetry and impedance spectroscopy. The MoSe2 nanomaterials were found to have superior electrochemical performance towards the hydrogen evolution reaction with a lower Tafel slope, on-set potential and potential at 10 mA/cm2 compared to the wrinkled few-layer nanosheets. This was found to be due to the higher effective electrochemical surface area of the nanoflowers compared to the nanosheets which suggests a higher number of exposed edge sites in the nanoflowers.

The poor oxidation resistance of refractory high-entropy alloys (RHEAs) is a major obstacle for their use in high-temperature engineering applications. Anti-oxidation coating technology is an effective method for improving the oxidation resistance. In this paper, the Si-20Cr-20Fe coating was prepared on MoNbTaTiW RHEA by a fused slurry method. The microstructural evolution and compositions of the silicide coating under high-temperature oxidation environment were studied. The results show that the silicide coating could effectively prevent the oxidation of the MoNbTaTiW RHEA. The initial silicide coating had a double-layer structure; a high silicon-content layer mainly composed of MSi2 as the outer layer and a low silicon-content layer mainly contained M5Si3 as the inner layer. Under high-temperature oxidation conditions, the silicon element diffused from the silicide coating to the RHEA substrate while the oxidation of the coating occurred. After oxidation, the coating was composed of an outer oxide layer and an inner silicide layer. The silicide layer moved toward the inside of the substrate, led to the increase of its thickness. Compared with the initial silicified layer, its structure did not change significantly. The structure and compositions of the oxide layer on the outer surface strongly depended on the oxidation temperature. This paper provides a strategy for protecting RHEAs from oxidation at high-temperature environments.

The influence of post-processing conditions on the magnetic properties of amorphous and nanocrystalline microwires have been thoroughly analyzed, paying attention on the influence of magnetoelastic, induced and magnetocrystalline anisotropies on the hysteresis loops of Fe-, Ni- and Co-rich microwires. We showed that magnetic properties of glass-coated microwires can be tuned by the selection of appropriate chemical composition and geometry in as-prepared state or further considerably modified by appropriate post-processing, which consists of either annealing or glass-coated removal. Furthermore, stress-annealing or Joule heating can further effectively modify the magnetic properties of amorphous magnetic microwires owing to induced magnetic anisotropy. Devitrification of microwires can be useful for either magnetic softening or magnetic hardening of the microwires. Depending on the chemical composition of the metallic nucleus and on structural features (grain size, precipitating phases) nanocrystalline microwires can exhibit either soft magnetic properties or semi-hard magnetic properties. We demonstrated that the microwires with coercivities from 1 A/m to 40 kA/m can be prepared.

Since the discovery of the aggregation-induced emission effect in 2001, diaminodicyanoquinone derivatives (DADQs) have presented interesting fluorescence properties, allowing them to be considered fluorescent dyes capable of showing quantum yields above 90%. Besides, the diaminodiacyanoquinone core represents a versatile building block propense either to modification or integration into different systems to obtain and provide them unique photophysical features. Herein, we carried out a theoretical study on the fluorescence properties of three different diaminodicyanoquinodimethane systems. Therefore, time-dependent density functional theory (TD-DFT) was used to obtain the values associated with the dipole moments, oscillator strengths, and the conformational energies between the ground and the first excited states of each molecule. The results suggest that only two of the three studied systems possess significant luminescent properties. In a further stage, the theoretical insights were confirmed by means of experimental measurements, which not only retrieved the luminescence of the DADQs, but also suggest a preliminary and promising antibacterial activity of these systems.

We fabricate paper-supported semiconducting devices by rubbing a layered molybdenum disulfide (MoS₂) crystal onto a piece of paper, similarly to the action of drawing/writing with a pencil on paper. We show that the abrasion between the MoS₂ crystal and the paper substrate efficiently exfoliates the crystals, breaking the weak van der Waals interlayer bonds and leading to the deposition of a film of interconnected MoS₂ platelets. Employing this simple method, that can be easily extended to other 2D materials, we fabricate MoS₂-on-paper broadband photodectectors with spectral sensitivity from the ultraviolet (UV) to the near-infrared (NIR). We also used these paper-based photodetectors to acquire pictures of objects by mounting the photodetectors in a homebuilt single-pixel camera setup.

The current emerging COVID-19 pandemic has caused a global impact on every major aspect of our societies. It is known that SARS-Cov-2 can endure harsh environmental conditions for up to 72 h, which may contribute to its rapid spread. Therefore, effective containment strategies, such as sanitizing, are critical. Nanotechnology can represent an alternative to reduce the COVID-19 spread, particularly in critical areas, such as healthcare facilities and public places. Nanotechnology-based products are effective at inhibiting different pathogens, including viruses, regardless of their drug-resistant profile, biological structure, or physiology. Although there are several approved nanotechnology-based antiviral products, this work aims to highlight the use of nanomaterials as sanitizers for the prevention of the spread of mainly SARS-Cov-2. It has been widely demonstrated that nanomaterials are an alternative for sanitizing surfaces to inactivate the virus. Also, antimicrobial nanomaterials can reduce the risk of secondary microbial infections on COVID-19 patients, as they inhibit the bacteria and fungi that can contaminate healthcare-related facilities. Finally, cost-effective, easy-to-synthesize antiviral nanomaterials could reduce the burden of the COVID-19 on challenging environments and in developing countries.

In a recent reformulation of the Marrucci-Ianniruberto constitutive equation for the rheology of entangled polymer melts in the context of non-equilibrium thermodynamics, rather large values of the convective constraint release parameter \beta_{ccr} had to be used in order not to violate the second law of thermodynamics. In this work, we present an appropriate modification of the model which avoids the splitting of the evolution equation for the conformation tensor into an orientation and a stretching part. Then, thermodynamic admissibility dictates simply that \beta_{ccr}≥ 0, thus allowing for more realistic values of \beta_{ccr} to be chosen. Moreover, and in view of recent experimental evidence for a transient stress undershoot (following the overshoot) at high shear rates whose origin may be traced back to molecular tumbling, we have incorporated in the model additional terms accounting, at least in an approximate way, for non-affine deformation through a slip parameter \xi. Use of the new model to describe available experimental data for the transient and steady-state shear and elongational rheology of entangled polystyrene melts and solutions shows close agreement. Overall, the modified model proposed here combines simplicity with accuracy, which renders it an excellent choice for managing complex viscoelastic fluid flows in large-scale numerical calculations.

It is highly likely that the wearing of face masks reduces the rate of respiratory infections (e.g. SARS-CoV-2), to protect both the user and those around them. This paper sets out to review the areas that effect the efficacy of masks, the materials, design, hygiene and fit testing, in order to make recommendations as to how to make mask from resources found in most homes for when commercial models are unavailable. This paper finds that a mask constructed with a filter made from high thread count cotton is likely to provide a reasonable level of protection (~70% filtration) and that if a layers of other materials such as chiffon or silk is added the filtration may be much higher (~90%). There is also some promise in less available materials such as vacuum cleaner bags and air conditioner filters. Examples of fabric and rigid designs are reviewed but most are limited by the fit to the users which is hard to determine in a home setting. It would be extremely helpful if a method was devised for people to test or be tested for the fit of home made masks. In the mean time careful thought should be given to whether the user judges a good fit. Users should also be careful to practice other means of hygiene and distancing.

For the generation of representative volume elements a statistical description of the relevant parameters is necessary. These parameters usually describe the geometric structure of a single grain. Commonly, parameters like area, aspect ratio and slope of the grain relative to the rolling direction are applied. However, usually simple distribution functions like log normal or gamma distribution are used. Yet, these do not take the interdependencies between the microstructural parameters into account. To fully describe any metallic microstructure though, these interdependencies between the singular parameters need to be accounted for. To accomplish this representation, a machine learning approach was applied in this study. By implementing a Wasserstein generative adversarial network, the distribution, as well as the interdependencies could accurately be described. A validation scheme was applied to verify the excellent match between microstructure input data and synthetically generated output data.

Hybrid microparticles based on an iron core and amphiphilic shell have been prepared to respond simultaneously to external (magnetic and ultrasounds field) and internal (pH) stimuli for delivery of the anticancer drug doxorubicin. The microparticles have been prepared in three main steps; including surface modification of the iron core followed by conjugation with the amphiphilic chitosan and drug loading. The particles demonstrate spherical shape and dimension in the range 1-3 m with tunable surface charge by changing the pH of surrounding environment. The microparticles demonstrate good stability in simulated physiological solutions and able to allocate up to 400 g of drug per mg of bare carrier. The response to ultrasound and the changes in the shell structure when exposed to different pH allows to control the doxorubicin release. In vitro cytotoxicity tests performed on fibloblast NIH/3T3 demonstrate a reduction in the cell viability when doxorubicin was administrated by microparticles compared to the free formulation; in particular when ultrasound were applied. The bare microparticles demonstrate cytocompatibility and hemocompatibility up to 50g/mL and 60 g/mL, respectively.

The present novel corona virus (2019-nCoV) infection has created a global emergency situation by spreading all over the world in a large scale within very short time period. The infection induced death rate is also very high. There is no vaccine or anti-viral medicine for such infection. So at this moment a major worldwide problem is that how we can control this pandemic. On the other hand, India is a high population density country, where the corona virus disease (COVID-19) has started to spread from $1^{st}$ week of March, 2020 in a significant number of COVID-19 positive cases. Due to this high population density human to human social contact rate is very high in India. So control of the pandemic COVID-19 in early stage is very urgent and challenging problem. Mathematical models are employed in this paper to study the COVID-19 dynamics, to identify the influential parameters and to find the proper prevention strategies to reduce the outbreak size. In this work, we have formulated a deterministic compartmental model to study the spreading of COVID-19 and estimated the model parameters by fitting the model with reported data of ongoing pandemic in India. Sensitivity analysis has been done to identify the key model parameters. The basic reproduction number has been estimated from actual data and the effective basic reproduction number has been studied on the basis of reported cases. Some effective preventive measures and their impacts on the disease dynamics have also been studied. Future trends of the disease transmission has been Predicted from our model with some control measures. Finally, the positive measures to control the disease have been summarized.

A methodology is proposed for designing the stabilization process of polyacrylonitrile (PAN) fibers. In its core, this methodology is based on a model that describes the characteristic fiber length change during the treatment, through the de-convolution of the three main contributors (i.e. entropic shrinkage, creep, and chemical shrinkage). The model has the additional advantage of offering further insight into the physical and chemical phenomena taking place during the treatment. Validation of PAN-model prediction performance for different processing parameters was achieved as demonstrated by FTIR and DSC. Τensile testing revealed the effect of processing parameters on fiber quality, while model prediction demonstrated that ladder polymer formation is accelerated at temperatures over 200oC. Additionally, according the DSC and FTIR measurements predictions from the application of the model during stabilization seem to be more precise at high-temperature stabilization stages. It was shown that mechanical properties could be enhanced preferably by including a treatment step below 200oC, before the initiation of cyclization reactions. Further confirmation was provided via Raman spectroscopy, which demonstrated that graphitic like planes are formed upon stabilization above 200oC, and thus multistage stabilization is required to optimize synthesis of carbon fibers. Optical Microscopy proved that isothermal stabilization treatment did not severy alter the cross section geometry of PAN fiber monofilaments.

Zinc-oxide (ZnO) nanostructures including nanorods are currently considered as a pioneer research of interest world-wide due to their excellent application potentials in various applied fields especially for the improvement of energy harvesting photovoltaic solar cells (PSC). We report on the growth and morphological properties of zinc-oxide (ZnO) nanorods grown on the surface of plain zinc (non-etched and chemically etched) plates by using a simple, economical, and environment-friendly technique. We apply hot water treatment (HWT) technique to grow the ZnO nanorods and varies the process parameters, such as temperature and the process time duration. The morphological, and elemental analysis confirm the agglomeration of multiple ZnO nanorods with its proper stoichiometry. The obtained nanostructures for different temperatures with different time duration showed the variation in uniformity, density, thickness and nanonorods size. The ZnO nanorods produced on the etched zinc surface were found thicker and uniform as compared to those grown on the non-etched zinc surface. This chemically etched Zinc plates preparation can be an easy solution to grow ZnO nanorods with high density and uniformity suitable for PSC applications such as to enhance the energy conversion efficiency of the photovoltaic (PV) solar cells towards the future sustainable green earth.

Hot deformation at elevated temperature is essential to densify the particle reinforced Aluminum matrix composites (AMCs) and improve their performance. However, hot deformation behavior of the AMCs is sensitive to the variation of hot processing parameters. In this paper, optimal processing parameters of the dual-scale SiCp/A356 composites was determined to explore the control strategy of the microstructure. Hot compression tests were conducted at the temperature ranging from 460 to 520℃ under strain rates from 0.01 to 5 s−1. Constitutive equation and processing maps were presented to determine the hot processing parameters. Microstructure evolution of the dual-scale SiCp/A356 composites was analyzed. The strain rate of 0.62 ~ 5s-1 and deformation temperature of 495 ~ 518℃ is suitable for the hot processing. The number of DRX grains in the “safe” domains is larger and the dislocation density is lower compared to those of instability domains. DRX particles mainly occurred around SiC particles. The presence of SiC particles can promote effectively the DRX nucleation, which result in that the dynamic softening mechanism of the dual-scale SiCp/A356 composites is dominated DRX.

At different heat treatment temperatures, the hardness and flexural strength of M2 high-speed steel selective laser melting (SLM) parts show mixed trends. When the heat treatment temperature is 260°C, the hardness and flexural strength of the M2 high-speed steel SLM part are decreased, but the hardness difference between the upper and lower surfaces of the M2 high-speed steel SLM part is also reduced. When the heat treatment temperature is 560°C, the hardness and flexural strength of the M2 high-speed steel SLM part are almost close to that of the original M2 high-speed steel SLM part, and the performance gradient in the sample is improved, and the overall structure is uniform. When the subsequent heat treatment temperature is 860 °C, the hardness of the SLM parts reaches a minimum, with an average value of 24 HRC. However, the flexural strength exceeds that of the original SLM parts. Moreover, the microstructure of the sample is uniform, which significantly improves the anisotropy of performance.

The evolution of metals micro/nano-structure upon severe plastic deformation (SPD) is still far to be theoretically explained, while experimental datasets are persistently growing for several decades. Major problem associated with understanding of SPD is related to a fact that the latter is a synergetic product of several competing physical effects which alter the material micro/nano-structure. In attempt to find deformational boundaries, where predominantly one mechanism determines the micro/nano-structure, in this paper we propose a continuous piecewise model for the analysis of experiments on material hardness vs strain of SPD processed materials. The novelty of this approach lies in its ability to find, as free-fitting parameters, the strain breakpoints which separate different micro/nano-structure modes generated upon SPD process. The model is applied to analyse experimental data for polycrystalline samples of pure iron and two distinctive strain breakpoints are revealed with good accuracies. This finding is in a good agreement with our earlier results on TEM microscopy studies on pure iron polycrystals after SPD treatment.

Three-dimensional (3D) printing techniques have received considerable focus in the area of bone engineering due to its precise control in the fabrication of complex structures with customizable shapes, internal and external architectures, mechanical strength, and bioactivity. In this study, we design a new composition biomaterial consisting of polylactic acid (PLA), and halloysite nanotubes (HNTs) loaded with zinc nanoparticles (PLA+H+Zn). The hydrophobic surface of the 3D printed scaffold was coated with two layers of fetal bovine serum (FBS) on the sides and one layer of NaOH in the middle. Additionally, a layer of gentamicin was coated on the outermost layer against bacterial infection. Scaffolds were cultured in standard cell culture medium without the addition of osteogenic medium. This surface modification strategy improved material hydrophilicity and enhanced cell adhesion. Pre-osteoblasts cultured on these scaffolds differentiated into osteoblasts and proceeded to produce a type I collagen matrix and subsequent calcium deposition. 3D printed scaffolds formed from this composition possessed high mechanical strength and showed an osteoinductive potential. Furthermore, the external coating of antibiotics not only preserved the previous osteogenic properties of the 3D scaffold but also significantly reduced bacterial growth. Our surface modification model enabled the fabrication of a material surface that was hydrophilic and antibacterial, simultaneously, with an osteogenic property. The designed PLA+H+Zn may be a viable candidate for the fabrication of customized bone implants.

There is an increasing interest in applying environmentally-friendly materials in wood protection technology. This include the use of less toxic active ingredients, as well as better fixation. This study investigates the formulation based on the combination of copper and Saqez resin on the physical and biological resistance properties of poplar wood. Samples were treated by either copper-ethanolamine (Cu/MEA) and/or Saqez resin at various treatment levels. A vacuum pressure procedure was applied. The retention, weight percent gain, water absorption, volumetric swelling, and decay resistance of the samples were then determined. The highest retention and weight percent gain were obtained at the samples treated with the combination of copper-based system and Saqez resin. Additionally, the combination of the copper and Saqez improved the physical properties and decay-resistance against white-rot fungus Trametes versicolor.

Calcium carbonate cements have been synthesized by mixing amorphous calcium carbonate and vaterite powders with water to form a cement paste and study how mechanical strength is created during the setting reaction. In-situ XRD was used to monitor the transformation of ACC and vaterite phases into calcite and a rotational rheometer was used to monitor the strength evolution. There are two characteristic time scales of the strengthening of the cement paste. The short timescale of the order 1 hour is controlled by smoothening of the vaterite grains, allowing closer and therefore adhesive contacts between the grains. The long timescale of the order 10-50 hours is controlled by the phase transformation of vaterite into calcite. This transformation is, unlike in previous studies using stirred reactors, found to be mainly controlled by diffusion in the liquid phase. The evolution of shear strength with solid volume fraction is best explained by a fractal model of the paste structure.

The meshless Petrov-Galerkin (MLPG) method is developed to analyse 2-D problems for flexoelectricity and thermoelectricity. Both problems are multiphysical and scale dependent. The size-effect is considered by the strain- and electric field-gradients in the flexoelecricity and higher-grade heat flux in the thermoelectricity. The variational principle is applied to de-rive the governing equations considered constitutive equations. The order of derivatives in governing equations is higher than in equations obtained from classical theory. The coupled governing partial differential equations (PDE) are satisfied in a local weak-form on small fic-titious subdomains with a simple test function. Physical fields are approximated by the mov-ing least-squares (MLS) scheme. Applying the spatial approximations in local integral equa-tions a system of algebraic is obtained for the nodal unknowns.

Dynamic thermogravimetric (TG) analysis under nitrogen environment was used to understand the thermal decomposition process of 3D printing filaments made of wood-filled polylactic acid (PLA)/starch blend. The characteristic temperatures and apparent activation energy (AAE) of the filaments with various starch contents were calculated with well-known kinetic models by Friedman, Flynn-Wall-Ozawa, Coats-Redfern and Kissinger. With the increased starch content in the filament, the onset thermal decomposition temperatures of the filaments decreased gradually from 272.4 to 155.1°C. The thermal degradation degree became smaller, and the transitional temperature interval became larger with increased starch proportion. The AAE values of the three types of filaments with different starch ratios varied between 97 kJ/mol and 114 kJ/mol, depending on material composition and method of calculation. The improved understanding of thermal decomposition behavior of PLA-starch-wood composites can help develop more biodegradable PLA/starch-based filaments for 3D printing.

This study was aimed at investigating the protective effects of glass ionomer cement (GIC) and surface pre-reacted glass ionomer (S-PRG) fillers used as dental restorative materials on demineralization of bovine enamel. GlasIonomer FX ULTRA (FXU), Fuji IX GP Extra (FIXE), CAREDYNE RESTORE (CDR) were used as GICs. PRG Barrier Coat (BC) was used as the S-PRG filler. They were incubated in a lactic acid solution (pH = 4.0) for 6 d at a temperature of 37 °C. The mineral was etched from the enamel surface, and a large number of Ca and P ions were detected in solution. The Al, F, Na, Sr, and Sr ions were released in GICs and S-RPG fillers. The Zn ion was released only in CDR and the B ion was released only in BC. The presence of apparent enamel prism peripheries was observed after 6 d of treatment for the group containing only enamel blocks. pH values for the FXU, FIXE, CDR, BC, and enamel block groups after 6 d were 6.5, 6.6, 6.7, 5.9, and 5.1, respectively. Therefore, the observed pH neutralization effect suppressed progression of caries due to the release of several ions from the restoratives.

We fabricate paper-supported semiconducting devices by rubbing a layered molybdenum disulfide (MoS₂) crystal onto a piece of paper, similarly to the action of drawing/writing with a pencil on paper. We show that the abrasion between the MoS₂ crystal and the paper substrate efficiently exfoliates the crystals, breaking the weak van der Waals interlayer bonds and leading to the deposition of a film of interconnected MoS₂ platelets. Employing this simple method, that can be easily extended to other 2D materials, we fabricate MoS₂-on-paper broadband photodectectors with spectral sensitivity from the ultraviolet (UV) to the near-infrared (NIR). We also used these paper-based photodetectors to acquire pictures of objects by mounting the photodetectors in a homebuilt single-pixel camera setup.

A mathematical model, composed of two non-linear differential equations that describe the population dynamics of CD4 T cells in the human immune system, as well as viral HIV particles, is proposed. The invariance region is determined, classical equilibria stability analysis is performed using the basic reproduction number, and numerical simulations are carried out, in order to illustrate stability results. Later, the model is modified with a delay term, which describes the time that cells require for immunological activation. This generates a two-dimensional integro-differential system, which is transformed into a system with three ordinary differential equations, via auxiliary variable use. For the new model, equilibrium points are determined, their local stability is examined, and results are studied by way of numerical simulation.

Bulk metallic glass matrix composites have emerged as competent structural material of future bearing potential structural applications. However, the optimum percentage of crystallinity required to produce enough toughness that it can serve as structural component is still a matter of debate. In this study, an effort is made to address this problem by inoculation. A controlled amount of carefully selected inoculant is introduced in Zr_47.5Cu_45.5Al₅Co₂ bulk metallic glass matrix composite during melting and solidification. Its effect in promoting crystallinity is checked by detailed electron back scatter diffraction (EBSD) mapping. Proper pattern capture, background correction, binning, Hough space transformation, step size selection, indexing and matching with well-defined crystal structure files have shown to reflect upon map quality. This shows and bears direct relation with effect of inoculation. Results from two independent laboratories are reported. Inoculation treatment is shown to be advantageous.

In the present work, the state of the art of the most common additive manufacturing (AM) technologies used for the manufacturing of complex shape structures of graphene-based ceramic nanocomposites, ceramic and graphene-based parts is explained. A brief overview of the AM processes for ceramic, which are grouped by the type of feedstock used in each technology, is presented. The main technical factors that affect the quality of the final product were reviewed. The AM processes used for 3D printing of graphene-based materials are described in more detail; moreover, some studies in a wide range of applications related to these AM techniques are cited. Furthermore, different feedstock formulations and their corresponding rheological behaviour were explained. Additionally, the most important works about the fabrication of composites using graphene-based ceramic pastes by Direct Ink Writing (DIW) are disclosed in detail and illustrated with representative examples. Various examples of the most relevant approaches for the manufacturing of graphene-based ceramic nanocomposites by DIW are provided.

Background: Nowadays investigations in the field of dental implants engineering are focused on bioactivity and osseointegration properties.Objective: In this study, the oxide-covered titanium was functionalized by vitamin D3 molecules via a simple self-assembly method with the aim to design more corrosion resistant and at the same time more bioactive surface.Methods: Surface properties of the D3-coated titanium were examined by scanning electron microscopy, attenuated total reflectance Fourier transform infrared spectroscopy, and contact angle measurements, while a long-term corrosion stability during immersion in an artificial saliva solution was investigated in situ by electrochemical impedance spectroscopy.Results: Results of all techniques confirmed a successful formation of the D3 vitamin layer on the oxide-covered titanium. Besides very good corrosion resistivity (~5 MΩcm² ) the D3-modified titanium surface induced spontaneous formation of biocompatible bone-like calcium phosphates (CaP).Conclusion: Observed in vitro CaP-forming ability as a result of D3-modified titanium/artificial saliva interactions could serve as a promising predictor of in vivo bioactivity of implant materials.

We fabricate large-area atomically thin MoS₂ layers through the direct transformation of crystalline molybdenum trioxide (MoO₃) by sulfurization at relatively low temperatures. The obtained MoS₂ sheets are polycrystalline (~10-20 nm single-crystal domain size) with areas of up to 300×300 µm² with 2-4 layers in thickness and show a marked p-type behaviour. The synthesized films are characterized by a combination of complementary techniques: Raman spectroscopy, X-ray diffraction, transmission electron microscopy and electronic transport measurements.

In this study, differences in the kinetics of thermal-supported hydrolytic degradation of poly(lactic acid) (PLA) sample wet spinning fibres due to material variance in the initial molecular and supramolecular structure were analysed. The investigation was carried out at the microstructural and molecular levels by using readily available methods such as scanning electron microscopy, mass erosion measurement and estimation of intrinsic viscosity. The results show a varying degree of influence of the initial structure on the degradation rate of studied PLA fibres. The experiment shows that hydrolytic degradation at a temperature close to the cold crystallization temperature on a macroscopic level is definitely more rapid for the amorphous material, while on a molecular scale it is similar to a semi-crystalline material. Further, for the adopted degradation temperature of 90 °C, a marginal influence of pH of the degradation medium on the degradation kinetics was also demonstrated

Influence of particle size on the mechanical strength of alkali activated material from waste refractory monolithic was investigated in this study. Precursor was chemically and mineralogically analysed, separated on 4 fractions and alkali activated with Na-water glass. Alkali activated materials were thoroughly investigated under SEM and XRD to evaluate the not predicted differences in mechanical strength. Time dependence of curing temperature on mechanical strength was investigated in the sample prepared from a fraction that caused the highest compressive strength.

The interlaminar strength of mechanically interlocked polymer-metal-interfaces is strongly dependent on the surface structure of the metal component. Therefore, this contribution assesses the suitability of the fractal dimension for quantification of the surface structure as well as interlaminar strength prediction of aluminum/polyamide 6 polymer-metal-hybrids. Seven different surface structures, manufactured by blasting, combined blasting and etching, thermal spraying and laser ablation, are investigated. The experiments are carried out on a novel butt-bonded hollow cylinder testing method that allows shear and tensile strength determination with one specific specimen geometry. The fractal dimension of the metal surfaces is derived from cross-sectional images. For comparison, the surface roughness slope is determined and related to the interlaminar strength. Finally, a fracture analysis is conducted. For the investigated material combination, the experimental results indicate that the fractal dimension is an appropriate measure for predicting the interlaminar strength

The research hypothesis states that the impregnation of the honeycomb paper core of lightweight sandwich panels with modified starch, sodium silicate and LiquidWood® resin has a significant effect on the elastic properties of it. In the study, a recycled paper was used in three thicknesses, seven types of cell shapes, including two after numerical optimization and three types of impregnating agents. The method of digital image analysis determined the elastic constants of manufactured paper cores, which were subjected to axial compression in two directions. Based on the experimental results, elastic constants of the cores were calculated and compared with the results of numerical calculations. It has been shown that each of the impregnating solutions used improves the stiffness of the paper core. The best results were obtained for LiquidWood® epoxy resin and modified starch. An important parameter of cell geometry affecting their rigidity is the angle of the cell wall φ, as well as the arrangement of the common cell wall in relation to the direction of load. The numerical models developed were positively verified.

The study presents the effect of annealing process parameters on the microstructure, hardness and strain hardening coefficients i.e., the strength coefficient c and the strain hardening exponent n, of 42CrMo4 steel. Seven selected annealing time-temperature schemes are examined for superior steel formability in cold metal forming conditions. The c and n coefficients are first determined in experimental upsetting of annealed samples and then used in FEM simulations of the upsetting process. The results demonstrate that the strain hardening coefficients (c and n) depend on the employed annealing scheme. Compared to the as-received sample, the annealing process reduces the true stress and effectively decrease the hardness of 42CrMo4 steel, improves microstructural spheroidization and, consequently, facilitates deformability of this material. The annealing schemes relying on heating the material to 750 °C and its subsequent slow cooling lead to the highest decrease in hardness ranging from 162 to 168HV. Results obtained with the SEM-EDS, LOM and XRD methods lead to the conclusion that the employed heat treatment schemes cause the initial ferritic-pearlitic microstructure to develop granular and semi-lamellar precipitation of cementite enriched with Mo and Cr in the ferrite matrix. In addition, the annealing process affects the growth of α-Fe grains. The highest cold hardening rate, and thus formability, is obtained for the annealing scheme producing the lowest hardness. The results of FEM simulations are positively validated by experimental results. Obtained results are crucial for further numerical simulations and experimental research connected with developing new cold metal forming methods for producing parts made of 42CrMo4 steel.

We investigated the protective effects of glass ionomer cement (GIC) and surface pre-reacted glass ionomer (S-PRG) fillers used as dental restorative materials on the demineralization of bovine enamel during the incubation in a lactic acid solution with pH = 4.0 conducted for 6 d at a temperature of 37 °C. Scanning electron microscopy images of the specimen surfaces from the group containing only enamel blocks revealed the presence of apparent enamel prism peripheries after 6 d of treatment. The mineral was etched from the enamel surface, and a large number of Ca ions were detected in solution. In contrast, the enamel blocks incubated together with discs of GIC or S-PRG fillers did not exhibit demineralized surfaces, owing to the neutralization of the acid solution by the fillers within the first 3 h of the incubation process. The observed pH neutralization effect was attributed to the release of different ions from the fillers and could be utilized for suppressing the progression of caries.

This paper presents a physical and mathematical model that has been developed in the framework of the approach used in the computational mechanics of materials. The model is designed to enable the study of the patterns of deformation and fracture of ceramic composites with a transformation-hardened matrix that are obtained by additive technologies at the mesoscopic and macroscopic levels under intense dynamic loading. The influence of the loading rate on the formation of the fracture and energy dissipation fronts for composite materials, based on the Al2O3 20%ZrO2 system, is shown. Nonlinear effects under intense dynamic loading in the considered composites are associated with the processes of self-organization of structural fragments at the mesoscopic level, as well as the occurrence of martensitic phase transformations in matrix volumes adjacent to the strengthening particles.

Polypropylene (PP) is commonly used in the polymer processing industry. Its feature is a good chemical resistance, it is non-toxic and not harmful to people. Polypropylene is widely used in the manufacturing of food packages, laboratory and medical equipment, electric cables insulators, automotive parts, toys and furniture. The application of this material enables us to obtain complicated shapes of big surfaces. It is also highly recyclable. Polylactide (PLA) is a product of the so called “green chemistry” because it is obtained from the renewable raw materials (biomass). As its price is higher compared to the traditional polymers, its repeated use (recycling) is of high interest. Due to the same reason (cost) the mixtures of PLA with other polymers are applied. In this paper the results of testing the PP/PLA mixtures of various mass ratio of the components are presented. Technical terms of preparing and processing such mixtures have been practically tested. Also the mechanical strength was determined based on the static tensile tests. The results showed that those mixtures can be repeatedly processed. Even five-times reprocessing does not cause essential drop of mechanical properties