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In this paper, the influence of the variation in transformer oil temperature on the accuracy of the all-acoustic non-iterative method for partial discharge location in a power transformer is researched. The research can improve power transformers’ testing and monitoring, particularly given the large transformer oil temperature variations during real-time monitoring. The research is based on quantifying the contribution of oil temperature to the standard combined measurement uncertainty of the non-iterative algorithm by using analytical, statistical, and Monte Carlo methods. The contribution can be quantified and controlled. The contribution varied significantly with different mutual placements of partial discharge and acoustic sensors. The correlation between the contribution and the mean distance between partial discharge and acoustic sensors was observed. Based on these findings, the procedure to quantify and control the contribution in practice was proposed. The procedure considers the specificity of the method’s mathematical model (the assumption that the oil temperature is constant), the non-iterative algorithm’s nonlinearity, and the large variations in transformer oil temperature. Existing studies did not consider the significant effect of the oil temperature on the combined measurement uncertainty of partial discharge location influenced by those phenomena. The research is limited to partial discharge located in the transformer oil.

The lack of a standard test method for evaluating the resistance of pervious concrete to cycles of freezing and thawing in the presence of deicing salts is the motive behind this study. Different sample size and geometry, cycle duration, and level of submersion in brine solutions were investigated to achieve an optimized test method. The optimized test method was able to produce different levels of damage when different types of deicing salts were used. The optimized duration of one cycle was found to be 24 h with twelve hours of freezing at −18 °C and twelve hours of thawing at +21 °C, with the bottom 10 mm of the sample submerged in the brine solution. Cylinder samples with a diameter of 100 mm and height of 150 mm were used and found to produce similar results to 150 mm-cubes. Based on the obtained results a mass loss of 3%–5% is proposed as a failure criterion of cylindrical samples. For the materials and within the cycles of freezing/thawing investigated here, the deicers that caused the most damage were NaCl, CaCl 2 and urea, followed by MgCl 2 , potassium acetate, sodium acetate and calcium-magnesium acetate. More testing is needed to validate the effects of different deicers under long term exposures and different temperature ranges.

The influence of different nozzle head geometries and, therefore, the variation of the excitation and relaxation volume on the energy flux from an atmospheric pressure plasma jet to a surface have been investigated. Measurements have been performed by passive calorimetric probes under variation of the gas flow through the nozzle. The results show that the geometry of the nozzle head has a significant impact on the resulting energy flux. The relaxation volume affects the dependence of the energy flux on the gas flow. While there is no significant influence of the working gas flow on the energy flux without a relaxation volume, utilizing a relaxation volume leads to a decrease of the energy flux with increasing working gas flow. Within the analyzed parameter range, the energy flux reveals for both nozzle heads a linear dependency on the applied primary voltage.

We report experiments in which radiatively metastable $2\,^{3}\mathrm {S}_{1}$ 2 3 S 1 positronium (Ps) atoms entered a waveguide whose internal surfaces were lined with smoked magnesium oxide (MgO) powder. The waveguide was built such that time-delayed microwave radiation pulses, tuned to drive $2\,^{3}\mathrm {S}_{1}\rightarrow 2\,^{3}\mathrm {P}_{2}$ 2 3 S 1 → 2 3 P 2 transitions, could be applied to the Ps ensemble. The lifetime of $2\,^{3}\mathrm {S}_{1}$ 2 3 S 1 atoms was measured using time-delayed microwave induced decay, yielding ≈200 ns. This is considerably shorter than the Zeeman shifted lifetime of 1070 ns, indicating that Ps atoms in the $2\,^{3}\mathrm {S}_{1}$ 2 3 S 1 state do not survive multiple collisions with MgO nanocrystals.

The Facility for Rare Isotope Beams (FRIB) will be a new scientific user facility that produces rare-isotope beams for experiments from the fragmentation of heavy ions at energies of 100–200 MeV/u. During the projectile fragmentation, the rare isotope of interest is produced along with many contaminants that need to be removed before the beam reaches detectors. At FRIB, this is accomplished with a magnetic projectile fragment separator. However, to achieve higher beam purity, in particular for proton-rich rare isotopes, additional purification is necessary. RadiaBeam in collaboration with Michigan State University (MSU) has designed a 20.125 MHz radiofrequency (RF) fragment separator capable of producing a 4 MV kick with 18 cm aperture in order to remove contaminant isotopes based on their time of flight. In this paper, we will discuss the RF and engineering design considerations of this separator cavity.

Measurements of the absolute sensitivity of three different optical cameras are presented. An absolutely calibrated tungsten strip-lamp was used for calibrating the devices. An experimental method for determining the solid angle which is accepted by the combination of the cameras with a broadband apochromatic lens is described. The results with five bandpass filters between 337nm and 740nm are shown. The signal to noise ratio and the spatial resolution of the camera systems is also discussed.

The aim of this work was to fabricate microporous poly(trimethylene carbonate) (PTMC) vascular structures by stereolithography (SLA) for applications in tissue engineering and organ models. Leachable CaCO3 particles with an average size of 0.56 &mu, m were used as porogens. Composites of photocrosslinkable PTMC and CaCO3 particles were cast on glass plates, crosslinked by ultraviolet light treatment and leached in watery HCl solutions. In order to obtain interconnected pore structures, the PTMC/CaCO3 composites had to contain at least 30 vol % CaCO3. Leached PTMC films had porosities ranging from 33% to 71% and a pore size of around 0.5 &mu, m. The mechanical properties of the microporous PTMC films matched with those of natural blood vessels. Resins based on PTMC/CaCO3 composites with 45 vol % CaCO3 particles were formulated and successfully used to build vascular structures of various shapes and sizes by SLA. The intrinsic permeabilities of the microporous PTMC films and vascular structures were at least one order of magnitude higher than reported for the extracellular matrix, indicating no mass transfer limitations in the case of cell seeding.

The microindentation experimental tests were carried out on Aluminum 6061-T6 films. A comparative study between the estimation of Martens hardness and that of indentation is implemented, through the mathematical modeling of these two hardnesses respectively. The indentation size effect is a determining factor in characterizing the hardness of the material studied. This phenomenon is dependent on the macrodureté which corresponds to the hardness obtained by the application of an infinite load. To take into account the deformation modes around the imprint, the indentation hardness is used unlike Martens' hardness which shows its limit, especially since the measurement scale is small. Hence, the advantages and advantages of using indentation hardness as an important informative property for micromechanical characterization of materials. The influence of the blunt tip defect due to its use is negligible in microhardness.

In this paper, an analytical solution for the analysis of the free vibration of plates in functionally graded material (FGM) is presented, considering the porosities that can occur inside the materials with gradient properties (FGM) during of their manufacture. A method based on high order theory will be presented to study the free vibration of FGM plates. The proposed theory contains four unknowns unlike other theories. The governing equations are obtained through the Hamilton’s principal and the closed form solutions in terms of natural frequencies are obtained by using Navier technique. The numerical results obtained through the present analysis are compared with the ones available in the literature. The effects of various parameters, such as thickness ratio, gradient index, and porosity factor on the free vibration of FGM plates are all discussed.

This aim of this paper is to do a rheological study on the cutting oil emulsions. The main objective is to perform an experimental study and a modeling of complex flow of these systems by varying, respectively, the oil concentration used and the temperature of the tests. The emulsion is composed of a mineral oil used at different concentrations of oil in distilled water. The surfactant "cationic sulfonates" Is used to ensure stability of the emulsion. The rheological parameters of the studied cutting oil emulsions are determined by using a viscometer with coaxial cylinders for a temperature range of 25 ° C. to 60 ° C. The characterization of the rheological behavior was done by using two computing programs. The first program is used to determine which is the most representative model of the rheological behavior of the emulsion. While the second is used to choose the most representative model of the variation of the viscosity as a function of temperature. The obtained experimental results show that the concentration and the temperature have a strong influence on the rheological behavior, and thus on the rheological parameters such as the flow index and the consistency. The results also showed that the dynamic viscosity is the most rheological parameter influenced by the variation of the temperature, where this variation can be represented by a polynomial of order 3.

The aim of this work is to make a contribution to study the ductile failure of polymers materials (Polyvinyldifluoride, PVDF) using the concepts of the local approach in fracture mechanics. The numerical simulation with the Ansys finite element code was carried out using a micromechanical model based on the local approach in order to study the ductile failure of polymers: the Gurson-Tvergaard-Needleman model; GTN. The validation of this finite element model was carried out using the experimental results. The GTN model faithfully reproduces the macroscopic mechanical behavior of the PVDF material in terms of stress versus strain at different level of temperature. The sensitivity of the PVDF mechanical behavior to some parameter such as: effect of triaxiality of stresses, temperature and hydrostatic pressure were examined. Secondly, the application of the elastoplastic fracture mechanics based on the determination of the J integral is used in order to study the fracture behavior of PVDF and its sensitivity to rise of level of temperature.

Improving the durability and sustainability of concrete structures has been driving the enormous number of research papers on self-healing mechanisms that have been published in the past decades. The vast developments of computer science significantly contributed to this and enhanced the various possibilities numerical simulations can offer to predict the entire service life, with emphasis on crack development and cementitious self-healing. The aim of this paper is to review the currently available literature on numerical methods for cementitious self-healing and fracture development using Phase-Field (PF) methods. The PF method is a computational method that has been frequently used for modeling and predicting the evolution of meso-and microstructural morphology of cementitious materials. It uses a set of conservative and non-conservative field variables to describe the phase evolutions. Unlike traditional sharp interface models, these field variables are continuous in the interfacial region, which is typical for PF methods. The present study first summarizes the various principles of self-healing mechanisms for cementitious materials, followed by the application of PF methods for simulating microscopic phase transformations. Then, a review on the various PF approaches for precipitation reaction and fracture mechanisms is reported, where the final section addresses potential key issues that may be considered in future developments of self-healing models. This also includes unified, combined and coupled multi-field models, which allow a comprehensive simulation of self-healing processes in cementitious materials. Fil: Yang, Sha. Universitat Technische Darmstadt; Alemania Fil: Aldakheel, Fadi. Leibniz Universitat Hannover.; Alemania Fil: Caggiano, Antonio. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Tecnologías y Ciencias de la Ingeniería "Hilario Fernández Long". Universidad de Buenos Aires. Facultad de Ingeniería. Instituto de Tecnologías y Ciencias de la Ingeniería "Hilario Fernández Long"; Argentina Fil: Wriggers, Peter. Leibniz Universitat Hannover.; Alemania Fil: Koenders, Eddie. Universitat Technische Darmstadt; Alemania

Since ash from wood biomass mostly ends up in landfills, recent research has focused on finding its economic and environmental added value as a potential new raw material in the construction industry. However, for wood ash to be used on an industrial scale in construction, a strategy for its proper storage must be defined. Proper storage of WBA is important to ensure quality control for applications in cementitious composites. This work investigated the aging of wood biomass ash (WBA) collected from five different power plants in Croatia and its influence on the performance of cementitious composites. WBA and cement pastes were investigated at different aging times (up to one year) using thermogravimetric analysis (TGA), powder X-ray diffraction (XRD), isothermal calorimetry and initial and final setting times. The results showed that storage of WBA in closed and open containers resulted in carbonation and hydration of mainly free lime and periclase, respectively, which affected the reactivity and setting times of WBA cement pastes.

Ionic liquid crystals occupy an intriguing middle ground between room-temperature ionic liquids and mesostructured liquid crystals. Here, we examine a non-polarizable, fully atomistic model of the 1-alkyl-3-methylimidazolium nitrate family using molecular dynamics in the constant pressure-constant temperature ensemble. These materials exhibit a distinct "smectic" liquid phase, characterized by layers formed by the molecules, which separate the ionic and aliphatic moieties. In particular, we discuss the implications this layering may have for electrolyte applications.

Co-based (Co75Si15B10) thin-film metallic glass (TFMG) with nanometric thicknesses (100~300 nm) was investigated for its structural, electrical, and optical properties. The TFMG structure was examined using scanning electron microscopy and X-ray diffraction, while electrical properties were examined using inductance/capacitance/resistance spectroscopy, cyclic voltammetry, and Hall effect measurements. In addition, optical absorption/reflection/transmittance measurements were performed to examine optical properties. Results revealed that Co-based TFMGs, which have an amorphous structure without surface defects, behave like a dielectric material, with higher resistivity and much lower carrier concentration than pure cobalt (Co) thin films of the same thickness, despite its mobility being modestly larger than its Co counterparts. Meanwhile, the optical investigation of TFMG enabled us to determine the complex relative permittivity (complex relative dielectric constant) at a visible wavelength (632.8 nm). Moreover, unlike normal metals, TFMGs exhibited a large positive value of the real part of , while exhibiting properties of substantial absorption of light (absorption coefficient ). It was also found that the Co-based TFMG gained optical transparency for thicknesses less than 5 nm. TFMGs demonstrated the nearly thickness-independent properties of the electrical and optical parameters probed, a feature of high-index, dielectric-like material with negligible size effects, which may have applications in micrometer-scaled optoelectronic and magneto-optical devices.

Nanomaterials that can be reversibly or irreversibly changed in structures and properties by the influence of external chemical and physical stimuli are defined as smart nanomaterials [...]

The purpose of this work is to obtain comprehensive reference data of the Ti-13Nb-13Zr alloy base material: its microstructure, mechanical, and physicochemical properties. In order to obtain extensive information on the tested materials, a number of examination methods were used, including SEM, XRD, and XPS to determine the phases occurring in the material, while mechanical properties were verified with static tensile, compression, and bending tests. Moreover, the alloy&rsquo, s corrosion resistance in Ringer&rsquo, s solution and the cytotoxicity were investigated using the MTT test. Studies have shown that this alloy has the structure &alpha, &rsquo, &alpha, and &beta, phases, indicating that parts of the &beta, phase transformed to &alpha, which was confirmed by mechanical properties and the shape of fractures. Due to the good mechanical properties (E = 84.1 GPa), high corrosion resistance, as well as the lack of cytotoxicity on MC3T3 and NHDF cells, this alloy meets the requirements for medical implant materials. Ti-13Nb-13Zr alloy can be successfully used in implants, including bone tissue engineering products and dental applications.

Investigations by electron backscatter diffraction (EBSD) and X-ray diffraction with the use of synchrotron radiation, as well as parallel extended finite element (XFEM) simulations, reveal the evolution of the 316L stainless steel microstructure in the vicinity of a macro-crack developing at the temperature of liquid helium (4.2 K). The fracture propagation induces a dynamic, highly localized phase transformation of face-centred cubic austenite into &alpha, &rsquo, martensite with a body-centred cubic structure. Synchrotron studies show that the texture of the primary phase controls the transition process. The austenite grains, tending to the stable Brass orientation, generate three mechanisms of the phase transformation. EBSD studies reveal that the secondary phase particles match the ordered austenitic matrix. Hence, interphase boundaries with the Pitsch disorientation are most often formed and &alpha, martensite undergoes intensive twinning. The XFEM simulations, based on the experimentally determined kinetics of the phase transformation and on the relevant constitutive relationships, reveal that the macro-crack propagates mainly in the martensitic phase. Synchrotron and EBSD studies confirm the almost 100% content of the secondary phase at the fracture surface. Moreover, they indicate that the boundaries formed then are largely random. As a result, the primary beneficial role of martensite as reinforcing particles is eliminated.

The low plasticity of high strength Mg-Gd-Y alloy has become the main obstacle to its application in engineering. In this paper, the origin, propagation and fracture processes of cracks of a solution of treated Mg-13Gd-5Y-3Zn-0.3Zr alloy were observed and studied with scanning electron microscopy (SEM) in an in situ tensile test to provide theoretical references for the development of a new high-performance Mg-Gd-Y alloy. The results showed that there was still some bulk long period stacking order (LPSO) phase remaining in solid solution Mg-13Gd-5Y-3Zn-0.3Zr alloy. Most importantly, it was found that the locations of micro-cracks vary with the different solution treatment processes, mainly including the following three types. (1) At 480 &times, 10 h and 510 &deg, C &times, 10 h, much bulk LPSO phase with higher elastic modulus remains in the alloy, which can lead to micro-cracks in the LPSO phase due to stress concentration. (2) At 510 &deg, 13 h and 510 &deg, 16 h, the phase structure of bulk LPSO changes, and the stress concentration easily appears at the LPSO/&alpha, Mg interface, which leads to micro-cracks at the interface. (3) At 510 &deg, 19 h and 510 &deg, 22 h, the grain size increases, and the stress concentration is obvious at the grain boundary of coarse grains, which leads to the formation of micro-cracks.

The primary aim of this article is to focus on the alkali-silica reaction (ASR) in mortar specimens containing coloured waste glass used as an aggregate. Mortar expansion was measured using the ASTM C 1260 accelerated test procedure until the specimens disintegrated. Special attention was paid to the microscopic examination of the damaged mortar. Various methods were used for this purpose, including optical microscopy in reflected and transmitted light with one and two crossed polarizers. The specimens were also subjected to the scanning electron microscopy observations with energy dispersive spectroscopy (SEM-EDS). The data obtained from these techniques provided information on the mechanism of glass-containing mortar degradation due to ASR and also allowed the comparison of different microscopic techniques in terms of the information they can provide on ASR occurrence.

The purpose of this work was to systematically assess the distribution of thermoluminescence (TL) and optically stimulated luminescence (OSL) properties along the length of crystals grown by the micro-pulling-down method, in relation to the microstructure and distribution of activators. We analyzed lithium magnesium phosphate (LiMgPO4, LMP) crystals doped with terbium (Tb, 0.8 mol%) or with a combination of thulium (Tm, 0.8 mol% or 1.2 mol%) and boron (B, 10 mol%). Crystals of several centimeters in length and 3 mm in diameter were cut into 20&ndash, 40 slices, depending on length. For each sample, TL glow curves and OSL decay curves were examined. Optical microscopy and scanning electron microscopy were used to assess the microstructure and elemental composition of several selected samples. Two-dimensional TL readouts were performed to identify the areas with higher and lower signal emission. Our study showed that there may be significant differences not only in LMP sensitivity along the crystal&rsquo, s axis but also on the surface of the slice. The distribution of activators varies depending on the type of crystals and strongly affects luminescence properties.

This work provides an analysis of X-ray micro computed tomography data of Sn-xBi solders with x = 20, 30, 35, 47, 58 wt.% Bi. The eutectic thickness, fraction of eutectic and primary phase are analyzed. Furthermore, the 3D data is evaluated by means of morphology parameters, such as, shape complexity, flatness, elongation and mean intercept length tensor. The investigated alloys are categorized in three groups based on their morphology, which are described as “complex dominant”, “complex- equiaxed” and “mixed”. The mechanical behavior of Sn-Bi alloys in the semi-solid configuration and the correlation with microstructural parameters are discussed. A varying degree of geometric anisotropy of the investigated alloys is found through the mean intercept length tensor. Representative volume element models for finite element simulations (RVE-FEM) are created from tomography data of each alloy to analyze a correlation of geometric and elastic anisotropy. The simulations reveal an elastic isotropic behavior due to the small difference of elastic constants of primary and eutectic phase. A discussion of properties in the semi-solid state and liquid phase healing is provided.

The quality and quantity of peri-implant soft tissues at the crestal portion of dental implants are important aspects to consider for a long-term successful implant-supported rehabilitation. Some relevant factors attributed to the implant health include mucosal thickness and keratinization. In this respect, many techniques and materials have been described to augment and improve buccal peri-implant soft tissues. Over the last few years, newly developed xenogeneic collagen matrices have been introduced in peri-implant plastic surgery to replace autogenous soft tissue grafts; however, data remain controversial so far. Thus, the purpose of the present report was to present a novel surgical technique conceived to augment buccal peri-implant soft tissues in combination with a volume-stable porcine collagen matrix. The rationale and the fundamental concepts that led to the use of a xenogeneic matrix to increase soft tissue volumes were also discussed.

The processing of high-precision aerospace parts requires not only ultra-precision machine tools, but also high-efficiency processing. However, in order to realize high-efficiency processing, besides optimizing the system and process parameters, some subversive research can also be done on the machine tool structure. In this paper, the lightweight research is mainly carried out on the structure of machine tool worktable. The traditional workbench is very &ldquo, heavy&rdquo, and &ldquo, slowness&rdquo, If the traditional workbench is subverted and reformed to reduce the weight, the processing efficiency will be improved qualitatively. Therefore, this paper studies the lightweight worktable of CFRP (carbon fiber reinforced polymer) in combination with the biological &ldquo, honeycomb&rdquo, shape. At first, the tensile, bending, compressive and laminar shear analysis of CFRP were carried out, and the comprehensive parameters were obtained. Simultaneously, the theoretical research and the honeycomb structure simulation and verification of CFRP worktable are carried out. The results show that the HACT (honeycomb arrangement of circular tubes) is 18.51% better than the SACT (straight arrangement of circular tubes) and 45.05% better than the OW (original worktable) by comparing and analyzing the weight of the three modes (HACT, SACT and OW). The actual weight of bionic honeycomb lightweight worktable is 1100 kg, while the simulation result is 1080.25 kg, with an error of 1.8%. Meanwhile, it is analyzed that the original workbench weight of the five-axis machining center is 2023 kg, while the simulation result is 1998.6 kg, with an error of 1.2%. The lightweight degree is reduced by 45.05%. However, the actual lightweight degree has been reduced by 45.63%. The error between simulation and actual is less than 1.3%. This kind of structural transformation has brought forward cutting-edge innovations to the machine tool processing industry. It provides a reference scheme for related enterprises in the future equipment renovation.

Use of magnesium implants is a new trend in orthopedic research because it has several important properties that recommend it as an excellent resorbable biomaterial for implants. In this study, the corrosion rate and behavior of magnesium alloys during the biodegradation process were determined by in vitro assays, evolution of hydrogen release, and weight loss, and further by in vivo assays (implantation in rabbits&rsquo, bone and muscle tissue). In these tests, we also used imaging assessments and histological examination of different tissue types near explants. In our study, we analyzed the Mg-1Ca alloy and all the hypotheses regarding the toxic effects found in in vitro studies from the literature and those from this in vitro study were rejected by the data obtained by the in vivo study. Thus, the Mg-1Ca alloy represents a promising solution for orthopedic surgery at the present time, being able to find applicability in the small bones: hand or foot.

Rotary swaging is an incremental metal forming process widely used to reduce the cross&ndash, section of parts. For tubular parts, the final wall thickness also changes during the process. The lubricant condition is a factor, which affects these geometry changes. Beneath the change of the geometry, the complex material flow during the process determines the final geometry and the mechanical properties. Therefore, with a thorough insight into the material flow, it could be understood how to control it in order to achieve desired properties. Producing tubes with uniform outer diameter and changing inner profiles is an application of this method. Furthermore, applying this method, different local cold hardening could be achieved by different total strain. In this study, the dependency of the material flow on the lubrication conditions was investigated. Simulations with combined hardening material models were verified by the change of the wall thickness of tubes. It was found that friction condition significantly influences the back shifting of the workpiece and the elongation caused by each stroke. Results from simulations and experiments showed that a certain lubricant condition leads to the highest axial elongation of the workpiece.

The doping behaviors of Pb in sulfoaluminate cement (SAC) clinker phases were systematically studied combined with density functional theoretical simulations and experiments. The results present that, in the three composed minerals of C4A3S, C2S, and C4AF, Pb ions prefer to incorporate into C4A3S by substituting Ca ions. Further analyses from partial density of states, electron density difference, and local distortions show that such doping preference can be attributed to the small distortions as Pb introduced at Ca sites of C4A3S. The results and clear understandings on the doping behaviors of Pb ions may provide valuable information in guiding the synthesis of Pb-bearing SAC clinker, thus should draw broad interests in fields from sustainable production of cement and environmental protection.

This contribution deals with the accuracy of machining during free-form surface milling using various technologies. The contribution analyzes the accuracy and surface roughness of machined experimental samples using 3-axis, 3 + 2-axis, and 5-axis milling. Experimentation is focusing on the tool axis inclination angle&mdash, it is the position of the tool axis relative to the workpiece. When comparing machining accuracy during 3-axis, 3 + 2-axis, and 5-axis milling the highest accuracy (deviation ranging from 0 to 17 &mu, m) was achieved with 5-axis simultaneous milling (inclination angles &beta, f = 10 to 15&deg, &beta, n = 10 to 15&deg, ). This contribution is also enriched by comparing a CAD (Computer Aided Design) model with the prediction of milled surface errors in the CAM (Computer Aided Manufacturing) system. This allows us to determine the size of the deviations of the calculated surfaces before the machining process. This prediction is analyzed with real measured deviations on a shaped surface&mdash, using optical three-dimensional microscope Alicona Infinite Focus G5.

Early establishment of soft-tissue adhesion and seal at the transmucosal and transcutaneous surface of implants is crucial to prevent infection and ensure the long-term stability and function of implants. Herein, we tested the hypothesis that treatment of titanium with ultraviolet (UV) light would enhance its interaction with epithelial cells. X-ray spectroscopy showed that UV treatment significantly reduced the atomic percentage of surface carbon on titanium from 46.1% to 28.6%. Peak fitting analysis revealed that, among the known adventitious carbon contaminants, C&ndash, C and C=O groups were significantly reduced after UV treatment, while other groups were increased or unchanged in percentage. UV-treated titanium attracted higher numbers of human epithelial cells than untreated titanium and allowed more rapid cell spread. Hemi-desmosome-related molecules, integrin &beta, 4 and laminin-5, were upregulated at the gene and protein levels in the cells on UV-treated surfaces. The result of the detachment test revealed twice as many cells remaining adherent on UV-treated than untreated titanium. The enhanced cellular affinity of UV-treated titanium was equivalent to laminin-5 coating of titanium. These data indicated that UV treatment of titanium enhanced the attachment, adhesion, and retention of human epithelial cells associated with disproportional removal of adventitious carbon contamination, providing a new strategy to improve soft-tissue integration with implant devices.

This research aimed to determine the durability and strength of an old concrete built-in arch bridge based on selected mechanical, physical, and chemical properties of the concrete. The bridge was erected in 1925 and is located in Jagodnik (northern Poland). Cylindrical specimens were taken from the side ribs connected to the top plate using a concrete core borehole diamond drill machine. The properties of the old concrete were compared with the present and previous standard requirements and guidelines. The laboratory testing program consisted of the following set of tests: measurements of the depth of carbonated zone and dry density, water absorption tests, determination of concrete compressive strength and frost resistance, determination of modulus of elasticity, measurement of the pH value, determination of water-soluble chloride salt and sulfate ion content, and X-ray diffraction analyses. Large variations in the cylindrical compressive strength (14.9 to 22.0 MPa), modulus of elasticity (17,900 to 26,483 MPa), density (2064 to 2231 kg/m3), and water absorption (3.88 to 6.58%) were observed. In addition to the experiments, a brief literature survey relating to old concrete properties was also conducted. This paper can provide scientists, engineers, and designers an experimental basis in the field of old concrete built-in bridge construction.

Three Fe-based ribbon-type samples prepared by a conventional planar flow casting process are studied from the viewpoint of the amorphous Fe80Si4B16 and partially surface crystallized Fe80Si10B10, and Fe80.5Nb6.9B12.6, microstructures. Surface magnetic properties are investigated by magneto-optical Kerr microscopy, allowing the measurement of a local hysteresis loop from a selected area on the ribbon surface, and simultaneously, a domain structure corresponding to a definite point at the loop. For an amorphous sample, the changes in the slopes of hysteresis loops are related either to the size of the selected surface area, from which the loop is measured, or to the type, width, and movement of magnetic domains through this area. In the first case, the resizing of the area simulates an effect of changing the diameter of the incident laser beam on the magneto-optical properties of the ribbon. In the latter case, the observed wide-curved and fingerprint domains are responsible for markedly different shapes of the hysteresis loops at lower magnetic fields. If the surface is crystallized, the magnetic properties are more homogenous, showing typical one-jump magnetization reversal with less dependence on the size of the surface area. The magneto-optical experiments are completed by transmission electron microscopy and magnetic force microscopy.

Small amounts of glycidylisobutyl polyhedral oligomericsilsesquioxane (G-POSS) (up to 10 phr) were added into a immiscible polyamide12 (PA12)/polyolefin elastomer (POE) blend (70 wt%/30 wt%) by simple melt mixing. The effects of the G-POSS on phase morphology and mechanical properties were investigated by FE-SEM, tensile testing, Izod impact test and dynamic mechanical analysis. FE-SEM analysis revealed that domain size of the dispersed POE phase in matrix PA12 is decreased significantly by adding the G-POSS, indicating a compatibilization effect of the G-POSS for the immiscible PA12/POE blend. The PA12/POE blend compatibilized with POSS showed simultaneous enhancement in mechanical properties including tensile modulus, strength and toughness. Further, thermally triggered shape memory effect was observed in this compatibilized blend.

A traditional penetration test only measures the total penetration within 5 s. The penetration process is not monitored, and therefore, a large amount of information on the deformation properties of asphalt is not used. This paper documents a study to use a high-speed camera to quantify the entire penetration process and use the Finite Element Method (FEM) to interpret the penetration process using a viscoelastic model. The penetration&ndash, time relationships of several asphalt binders (70#, 90#, a rubber modified binder, and a styrene-butadiene-styrene (SBS) modified binder) have been acquired using the new method, and the FEM modeling of the penetration processes is performed. The results show that both stress relaxation and creep appear during the penetration process. The results indicate that the improved test method and its data interpretation procedure may better characterize the properties of asphalt binder, which may extend the applications of the traditional penetration test.

In the Last decades, nanotechnology has provided novel and alternative methodologies and tools in the field of medical oncology, in order to tackle the issues regarding the control and treatment of cancer in modern society. In particular, the use of gold nanoparticles (AuNPs) in radiopharmaceutical development has provided various nanometric platforms for the delivery of medically relevant radioisotopes for SPECT/PET diagnosis and/or radionuclide therapy. In this review, we intend to provide insight on the methodologies used to obtain and characterize radiolabeled AuNPs while reporting relevant examples of AuNPs developed during the last decade for applications in nuclear imaging and/or radionuclide therapy, and highlighting the most significant preclinical studies and results.

More and more electrically conducting materials are required to sustain the technological progress of civilization. Faced with the performance limits of classical materials, the R&D community has put efforts into developing nanomaterials, which can offer sufficiently high operational parameters. In this work, single-walled carbon nanotubes (SWCNTs) were doped with polyethyleneimine (PEI) to create such material. The results show that it is most fruitful to combine these components at the synthesis stage of an SWCNT network from their dispersion. In this case, the electrical conductivity of the material is boosted from 249 ± 21 S/cm to 1301 ± 56 S/cm straightforwardly and effectively.

The inhibition behavior of carbon nanotubes (CNTs) and Gum Arabic (GA) on the corrosion of 316L stainless steel in CNTs&ndash, water nanofluid under the effect of different temperatures was investigated by electrochemical methods and surface analysis techniques. Thereby, 316L stainless steel samples were exposed to CNTs&ndash, water nanofluid under temperatures of 22, 40, 60 and 80 &deg, C. Two concentrations of the CNTs (0.1 and 1.0 wt.% CNTs) were homogenously dispersed in deionized water using the surfactant GA and tested using three corrosion tests conducted in series: open circuit test, polarization resistance test, and potentiodynamic scans. These tests were also conducted on the same steel but in solutions of GA-deionized water only. Tests revealed that corrosion increases with temperature and concentration of the CNTs&ndash, water nanofluids, having the highest corrosion rate of 32.66 milli-mpy (milli-mil per year) for the 1.0 wt.% CNT nanofluid at 80 &deg, C. In addition, SEM observations showed pits formation around areas of accumulated CNTs that added extra roughness to the steel sample. The activation energy analysis and optical surface observations have revealed that CNTs can desorb at higher temperatures, which makes the surface more vulnerable to corrosion attack.

This study proposes different manufacturing techniques (manual pelletization, powder pressing, and &ldquo, shell scaffold&rdquo, ) to obtain lightweight clay ceramics containing recovery raw materials. The sintering in an electrical furnace (1000 &deg, C, 1 h processing time) was conducted by traditional firing from room temperature, for pressed and shell-scaffold samples, while the flash heating (i.e., samples directly put at 1000 &deg, C) was used only for the pellets. The porous materials (porosity 40&ndash, 80%), functionalized with nutrients (K and P) in amounts to confer the fertilizer capability, gave suitable results in terms of pH (6.7&ndash, 8.15) and electrical conductivity (0.29&ndash, 1.33 mS/cm). Thus, such materials can be considered as feasible lightweight clay ceramics, with a positive effect on the soil. These findings permit us to hypothesize a potential use in green roofs or in agronomic applications.

One important challenge that faces the metallurgic industry turns around the constant increment in the mechanical resistance of certain finished products. Metallurgic advantages can be obtained from the inclusion of microparticles in metallic materials, but this inclusion involves complex challenges as the internal stress distribution can be modified. In this work, the simulation of a cooling sequence in 7075 aluminum with a SiO2 microparticle is presented. Two models of two-dimensional (2D) type were constructed in ANSYS&reg, 2019 with circular and oval shape microparticles located inside the aluminum. Both models were subjected to the same thermomechanical transient analysis to compare the remaining stress distributions around the microparticles after the thermal load and to observe the effect of the geometrical shape. The results show remaining stresses increased in the oval model as a consequence of the geometrical shape modification. After applying a tension load in the analyzed specimens, shear stress concentrations were observed with a higher magnitude around the covertex of the oval shape. The results can be very useful for the creation of materials with controlled remnant stress located in specific or desired locations in the matrix.

Aerodynamics has identified remarkable development in the improvement of fuel efficiency, reducing wind noise and increasing engine cooling. Moving body profile controls fuel the consumption rate. This paper discusses a novel car profile consisting of two airfoils Roncz (car profile) and National Advisory Committee for Aeronautics NACA 10 (car sides). They are used to create a streamlined body. Three-Dimensional numerical simulations of the full scale model (half domain) are performed to examine the effect of car profile on the drag coefficient and thus fuel consumption. Simulations are considered over a range of air flow velocities, from 20 to 45 km/h in a step of 5 km/h. The ahmed body is used to validate the results. Results are shown graphically for coefficients of drag and lift and pressure and velocity contours. They show that the design of the car profile is effective.

Reduced order models (ROMs) are computational models whose dimension is significantly lower than those obtained through classical numerical discretizations (e.g., finite element, finite difference, finite volume, or spectral methods). Thus, ROMs have been used to accelerate numerical simulations of many query problems, e.g., uncertainty quantification, control, and shape optimization. Projection-based ROMs have been particularly successful in the numerical simulation of fluid flows. In this brief survey, we summarize some recent ROM developments for the quasi-geostrophic equations (QGE) (also known as the barotropic vorticity equations), which are a simplified model for geophysical flows in which rotation plays a central role, such as wind-driven ocean circulation in mid-latitude ocean basins. Since the QGE represent a practical compromise between efficient numerical simulations of ocean flows and accurate representations of large scale ocean dynamics, these equations have often been used in the testing of new numerical methods for ocean flows. ROMs have also been tested on the QGE for various settings in order to understand their potential in efficient numerical simulations of ocean flows. In this paper, we survey the ROMs developed for the QGE in order to understand their potential in efficient numerical simulations of more complex ocean flows: We explain how classical numerical methods for the QGE are used to generate the ROM basis functions, we outline the main steps in the construction of projection-based ROMs (with a particular focus on the under-resolved regime, when the closure problem needs to be addressed), we illustrate the ROMs in the numerical simulation of the QGE for various settings, and we present several potential future research avenues in the ROM exploration of the QGE and more complex models of geophysical flows.

A promising approach to improve the poor antibacterial properties of dental composite resins has been the addition of metal oxide nanoparticles into the resin matrix. This systematic review aimed to determine whether the addition of zinc oxide nanoparticles (ZnO-NPs) improves the antibacterial properties of direct dental composite resins. This review was conducted in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines and registered with the PROSPERO database: CRD42019131383. A systematic literature search was conducted using the following databases: Medline (Ovid), the Cochrane Library, SCOPUS, CINAHL, Web of Science, Trove, Google Scholar, World Cat, and OpenGrey. The initial search retrieved 3178 results, which were then screened against inclusion and exclusion criteria, resulting in a total of four studies that were eligible for qualitative synthesis within this review. All the included studies were in vitro non-randomized post-test design experimental studies. A lack of congruity in the results obtained from these studies that used different tests to evaluate antibacterial activity was evident. Although some studies demonstrated a significant improvement of antibacterial properties in composites containing at least 1% ZnO-NPs (wt %), they are unlikely to present any clear clinical advantage due to the short lifetime of observed antibacterial properties.

Molybdenum-based alloys fabricated via selective laser melting are considered to represent the next generation of high-temperature structural materials, but the additive manufacturing technology aiming at refractory alloys has not been explored extensively. Multi-field coupling simulation can be used as a practical tool to simulate a single track of molybdenum alloy printed via selective laser melting, observe the topography of the molten pool over time, and determine the effect of Marangoni flow on defect suppression. In this study, the tmelt, tvapor, and the competition mechanism of spreading/solidification time were considered, the dominant spreading time was calculated, and a reasonable process parameter window for fabricating molybdenum alloy was obtained. It was found that keeping the energy density in the range of 3.1 &times, 1011 J/m3&ndash, 4.0 &times, 1011 J/m3 could better maintain appropriate melt channel depth and width and was beneficial to the droplet spreading behavior. This range was deemed suitable for printing molybdenum alloy.

This study evaluated the novel application of a mineral-rich biochar derived from a spent Agaricus bisporus substrate (SAS). Biochars with various pyrolysis temperatures (350&ndash, 750 &deg, C) were used to remove Cu(II), Zn(II), and Cd(II) from aqueous solutions. The adsorption characteristics and removal mechanisms of the biochars were investigated. The adsorption kinetics and isotherm data were fitted well by pseudo-second-order and Freundlich models. The Langmuir maximum removal capacity (Qmax) values of Cu(II), Zn(II), and Cd(II) were ordered as SAS750 &gt, SAS350 &gt, SAS550, and the Qmax values of SAS750 were 68.1, 55.2, and 64.8 mg&middot, g&minus, 1, respectively. Overall, the removal mechanisms of biochar at a low production temperature (350 &deg, C) to Cu(II), Zn(II), and Cd(II) were mainly via ion exchange (54.0, 56.0, and 43.0%), and at a moderate production temperature (550 &deg, C), removal mechanisms were mainly via coordination with &pi, electrons (38.3, 45.9, and 55.0%), while mineral precipitation (65.2, 44.4, and 76.3%, respectively) was the dominant mechanism at a high produced temperature (750 &deg, C). The variation of the mutual effect of minerals and heavy metals was the predominant factor in the sorption mechanism of mineral precipitation and ion exchange. The results demonstrated that spent Agaricus bisporus substrate biochar is a potential candidate for the efficient removal of heavy metals, which provides a utilization route for spent mushroom substrates.

In the present study, the dendrites deflection mechanism from the mold walls were subjected to verification regarding its heat-treated turbine rotor blades. The number of macroscopic low-angle boundaries created on the cross-section of the blades’ airfoil near the tip was experimentally determined and compared to the number of low-angle boundaries calculated from a model based on the dendrites deflection mechanism. Based on the Laue patterns and geometrical parameters of airfoils, the number of low-angle boundaries occurring at the upper part of the blades airfoil after heat treatment was calculated. This number for the analyzed group of blades ranged from 5 to 9.

This article describes utilization of a cement kiln bypass dust utilization as an added component in a hydraulic road binder. Three experimental binder mixes (BM1&ndash, BM3) with variation in the composition of the main constituents (cement clinker, ground limestone and ground granulated blast furnace slag) and constant content of bypass dust (10%) were prepared under laboratory conditions. The properties of binder constituents, fresh experimental binder mixes and hardened specimens were tested according to STN EN 13282-2 for a normal hardening hydraulic road binder. The physical and chemical properties of all binder mixes (fineness: +90 &micro, m &le, 15 wt.%, SO3 content: &lt, 4 wt.%) met the standard requirements. The bypass dust addition led to an increase in the water content for standard consistency of cement mixes (w/c = 0.23) and to a shortening of the initial setting time for two experimental blended cement pastes (BM1 and BM3) compared with the value required by the standard. Only BM2 with the lowest SO3 content (0.363 wt.%) and the highest percentage of granulated blast furnace slag (9.5 wt.%) and alkalis (Na2O and K2O content of 5.9 wt.%) in the binder mix met the standard value for the initial setting time (&ge, 150 min). The results of compressive strength testing of experimental specimens after 56 days of hardening (59.2&ndash, 63.9 MPa) indicate higher values than the upper limit of the standard requirement for the N4 class (&ge, 32.5, &le, 52.5 MPa).

The particle size distribution significantly affects the material properties of the additively manufactured parts. In this work, the influence of bimodal powder containing nano- and micro-scale particles on microstructure and materials properties is studied. Moreover, to study the effect of the protective atmosphere, the test samples were additively manufactured from 316L stainless steel powder in argon and nitrogen. The samples fabricated from the bimodal powder demonstrate a finer subgrain structure, regardless of protective atmospheres and an increase in the Vickers microhardness, which is in accordance with the Hall-Petch relation. The porosity analysis revealed the deterioration in the quality of as-built parts due to the poor powder flowability. The surface roughness of fabricated samples was the same regardless of the powder feedstock materials used and protective atmospheres. The results suggest that the improvement of mechanical properties is achieved by adding a nano-dispersed fraction, which dramatically increases the total surface area, thereby contributing to the nitrogen absorption by the material.

The paper presents a model of moisture transport in wood taking into account diffusion and the accompanying adsorption of water vapour through the skeleton. A two-parameter form of the source term was proposed, depending on the distance of the current moisture content (MC) from the equilibrium state. The tests on cubic samples with a side of 2 cm were carried out which allowed to determine the coefficients of the proposed model on the basis of the reverse method. The tests were performed for pine, larch, oak and ash in all directions of orthotropy. Tests on thin samples were also performed to verify the source term.

This work aims to better understand how small scale disturbances that are generated at the air-sea interface propagate into the surrounding atmosphere under realistic environmental conditions. To that end, a one-way coupled atmosphere-ocean model is presented, in which predictions of sea surface currents and sea surface temperatures from a microscale ocean model are used as constant boundary conditions in a larger atmospheric model. The coupled model consists of an ocean component implemented while using the open source CFD software OpenFOAM, an atmospheric component solved using the Weather Research and Forecast (WRF) model, and a Python-based utility foamToWRF, which is responsible for mapping field data between the ocean and atmospheric domains. The results are presented for two demonstration cases, which indicate that the proposed coupled model is able to capture the propagation of small scale sea surface disturbances in the atmosphere, although a more thorough study is required in order to properly validate the model.

In recent years, the application of fiber-reinforced plastics (FRPs) as structural members has been promoted. Metallic bolts and rivets are often used for the connection of FRP structures, but there are some problems caused by corrosion and stress concentration at the bearing position. Fiber-reinforced thermoplastics (FRTPs) have attracted attention in composite material fields because they can be remolded by heating and manufactured with excellent speed compared with thermosetting plastics. In this paper, we propose and evaluate the connection method using rivets produced of FRTPs for FRP members. It was confirmed through material tests that an FRTP rivet provides stable tensile, shear, and bending strength. Then, it was clarified that non-clearance connection could be achieved by the proposed connection method, so initial sliding was not observed, and connection strength linearly increased as the number of FRTP rivets increased through the double-lapped tensile shear tests. Furthermore, the joint strength of the beam using FRTP rivets could be calculated with high accuracy using the method for bolt joints in steel structures through a four-point beam bending test.

Phosphorization of metal oxides/hydoxides to promote electronic conductivity as a promising strategy has attracted enormous attention for improving the electrochemical properties of anode material in lithium ion batteries. For this article, selective phosphorization from NiCo2O4 to NiO/Ni2Co4P3 microspheres was realized as an efficient route to enhance the electrochemical lithium storage properties of bimetal Ni-Co based anode materials. The results show that varying phosphorizaed reagent amount can significantly affect the transformation of crystalline structure from NiCo2O4 to intermediate NiO, hybrid NiO/Ni2Co4P3, and, finally, to Ni2Co4P3, during which alterated sphere morphology, shifted surface valance, and enhanced lithium-ion storage behavior are detected. The optimized phosphorization with 1:3 reagent mass ratio can maintain the spherical architecture, hold hybrid crystal structure, and improve the reversibly electrochemical lithium-ion storage properties. A specific capacity of 415 mAh g&minus, 1 is achieved at 100 mA g&minus, 1 specific current and maintains at 106 mAh g&minus, 1 when the specific current increases to 5000 mA g&minus, 1. Even after 200 cycles at 500 mA g&minus, 1, the optimized electrode still delivers 224 mAh g&minus, 1 of specific capacity, exhibiting desirable cycling stability. We believe that understanding of such selective phosphorization can further evoke a particular research enthusiasm for anode materials in lithium ion battery with high performances.