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Everett Sawyer opublikował 1 rok, 3 miesiące temu
A facile solution process was employed to prepare CsPbI3 as an anode material for Li-ion batteries. Rietveld refinement of the X-ray data confirms the orthorhombic phase of CsPbI3 at room temperature. As obtained from bond valence calculations, strained bonds between Pb and I are identified within PbI6 octahedral units. Morphological study shows that the as-prepared δ-CsPbI3 forms a nanorod-like structure. The XPS analysis confirm the presence of Cs (3d, 4d), Pb (4d, 4f, 5d) and I (3p, 3d, 4d). The lithiation process involves both intercalation and conversion reactions, as confirmed by cyclic voltammetry (CV) and first-principles calculations. Impedance spectroscopy coupled with the distribution function of relaxation times identifies charge transfer processes due to Li metal foil and anode/electrolyte interfaces. An initial discharge capacity of 151 mAhg-1 is found to continuously increase to reach a maximum of ~275 mAhg-1 at 65 cycles, while it drops to ~240 mAhg-1 at 75 cycles and then slowly decreases to 235 mAhg-1 at 100 cycles. Considering the performance and structural integrity during electrochemical performance, δ-CsPbI3 is a promising material for future Li-ion battery (LIB) application.A wide variety of polymer additives have been widely used in recent years. However, the effect of different polymer additives on the durability of asphalt binders has not been investigated thoroughly. To evaluate the aging property of styrene-butadiene-styrene (SBS) asphalt binder with different polymer additives, three polymer modifiers, namely high modulus modifier (HMM), anti-rutting agent (ARA), and high viscosity modifier (HVM), were added to it. First, the Thin Film Over Test (TFOT) and Pressure Aging Vessel (PAV) was performed on the asphalt binders. The rheological properties of the four asphalt binders before and after aging were then checked by the Dynamic Shear Rheometer Test (DSR). The chemical compositions of the asphalt binders were determined by the Fourier Transform Infrared Spectrometer (FTIR) test. Several aging indicators were adopted to reflect the aging degree of the asphalt binders. The results show that when polymer additives are added to the SBS asphalt binder, the complex modulus, storage modulus, loss modulus, and rutting factor substantially increase and the phase angle decreases. All the test parameters become higher after aging. The phase angle of the SBS asphalt binder is the highest at both unaged and aged states, while its other parameters values are the smallest. Moreover, the Carbonyl Aging Indicator (CAI) of SBS with polymer additives becomes lower under both TFOT and PAV conditions, indicating that polymer additives can improve the aging resistance of SBS asphalt, of which HVM modifies the aging resistance best. Complex Modulus Aging Indicator (CMAI) and Storage Modulus Aging Indicator (SMAI) have the best correlation coefficients with CAI, and the two aging indicators can be used to predict the aging degree of polymer modified asphalt binders.The NOx removal performance of photocatalytic construction materials is demonstrated using two experiments under indoor and outdoor environments (1) A photoreactor test was conducted to assess the NO removal performance of construction materials (e.g., coatings, paints and shotcrete) using a modified ISO 22197-1 method; (2) A water washing test was conducted using two specimens enlarged to the size of actual building materials and artificially exposed to NOx in a laboratory to analyze NOx removal performance. For (1), the UV irradiation of the outdoor environment was analyzed and the experiment was conducted in an indoor laboratory under UV irradiation identical to that of the outdoor condition. Photoreactor tests were conducted on construction materials applied to actual buildings located in Seoul, South Korea. In (2), the enlarged specimen was used for a field experiment by applying a modified method from the ISO 22197-1 standard. On sunny days, the NOx removal performance (3.12-4.76 μmol/150 cm2·5 h) was twice as much as that of the ISO 22197-1 standard specification (2.03 μmol/150 cm2·5 h) in the real-world. The washing water test results indicated that general aqueous paint achieved a NOx removal of 3.88 μmol, whereas photocatalytic paint was superior to 14.13 μmol.Metamaterial absorbers (MMAs) with dynamic tuning features have attracted great attention recently, but most realizations to date have suffered from a decay in absorptivity as the working frequency shifts. Here, thermally tunable multi-band and ultra-broadband MMAs based on vanadium dioxide (VO2) are proposed, with nearly no reduction in absorption during the tuning process. Simulations demonstrated that the proposed design can be switched between two independently designable multi-band frequency ranges, with the absorptivity being maintained above 99.8%. Moreover, via designing multiple adjacent absorption spectra, an ultra-broadband switchable MMA that maintains high absorptivity during the tuning process is also demonstrated. Raising the ambient temperature from 298 K to 358 K, the broadband absorptive range shifts from 1.194-2.325 THz to 0.398-1.356 THz, while the absorptivity remains above 90%. This method has potential for THz communication, smart filtering, detecting, imaging, and so forth.In this study, Ti-6Al-4V alloy samples were processed by micro-arc oxidation (MAO) in phytic acid (H12Phy) electrolytes with the addition of different concentrations of EDTA-MgNa2 (Na2MgY) and potassium hydroxide (KOH). The surface characterization and cytocompatibility of MAO-treated samples were evaluated systematically. H12Phy is a necessary agent for MAO coating formation, and the addition of Na2MgY and KOH into the electrolytes increases the surface roughness, micropore size and Mg contents in the coatings. The MAO coatings are primarily composed of anatase, rutile, MgO and Mg3(PO4)2. Magnesium (Mg) ions in the electrolytes enter into MAO coatings by diffusion and electromigration. The MAO coatings containing 2.97 at% Mg show excellent cell viability, adhesion, proliferation, alkaline phosphatase activity, extracellular matrix (ECM) mineralization and collagen secretion, but the cytocompatibility of the MAO coatings containing 6.82 at% Mg was the worst due to the excessively high Mg content. Our results revealed that MAO coatings with proper Mg contents improve the cytocompatibility of the Ti-6Al-4V alloys and have large potential in orthopedic applications.Crystalline admixtures are employed for waterproofing concrete. This type of admixtures can affect the early age performance of cement-based mixes. The electrical resistance properties of cement have been related to the initial setting time and to the hydration development. This paper proposes a system for remote monitoring of the initial setting time and the first days of the hardening of cement-based mortars to evaluate the effect of the incorporation of crystalline admixtures. The electrical resistance results have been confirmed by other characterization techniques such as thermogravimetric analysis and compressive strength measurements. From the electrical resistance monitoring it has been observed that the incorporation of crystalline admixtures causes a delay in the initial setting time and hydration processes. The measurements also allow to evaluate the influence of the amount of admixture used; thus, being very useful as a tool to define the optimum admixture dosage to be used.This study investigates the durability of glass fiber-reinforced polymer (GFRP) reinforcing bars (rebars) and their bond in concrete. Accelerated aging tests were first conducted on bare rebars that were either subjected to direct immersion in an alkaline solution or previously embedded in concrete before immersion in the solution (indirect immersion). Accelerated aging was conducted at different temperatures of the solution (20 °C, 40 °C and 60 °C) and for various periods up to 240 days. Residual tensile properties were determined for rebars subjected to direct immersion and served as input data of a predictive Arrhenius model. A large decrease in the residual tensile strength assigned to the alkali-attack of glass fibers was extrapolated in the long term, suggesting that direct immersion is very severe compared to actual service conditions. Short-beam tests were also performed on rebars conditioned under direct/indirect immersion conditions, but did not reveal any significant evolution of the interlaminar shear strength (ILSS). In a second part, bond tests were performed on pull-out specimens after immersion in the alkaline solution at different temperatures, in order to assess possible changes in the concrete/GFRP bond properties over aging. Results showed antagonistic effects, with an initial increase in bond strength assigned to a confinement effect of the rebar resulting from changes in the concrete properties over aging, followed by a decreasing trend possibly resulting from interfacial degradation. Complementary characterizations by scanning electron microscopy (SEM), differential scanning calorimetry (DSC) and Fourier transform infrared (FTIR) spectroscopy were also carried out to evaluate the effects of aging on the physical/microstructural properties of GFRPs.The influence of melt injection temperature on the thermomechanical behaviour of soft-soft overmoulded vulcanized thermoplastic elastomers (TPV) with different elastic properties was studied. Samples with two different overmoulding temperatures were tested under uniaxial loading conditions. The full deformation and temperature fields in each TPV were determined using digital image correlation technique and infrared thermography, respectively. The maximum interface strength was found to be equal to 70N for a maximum injection temperature of 260∘C, which is consistent with the fact that high temperatures promote interdiffusion between the molten TPV and the TPV insert. The two TPV have different stiffness, leading to a significant change of the interface position along the specimens during stretching and to a significant necking in the softer material. The zone of influence of the interface in terms of stretch gradient is very different in size from one TPV to the other. In addition, thermal investigations have shown that the elasticity of the two TPV is due to both entropic and non-entropic effects, the former being the most significant at large strains.Biodegradable magnesium alloys with Zn, Yb, Ca and Sr additions are potential materials with increased corrosion resistance in physiological fluids that ensure a controlled resorption process in the human body. This article presents the influence of the use of a high cooling rate on the corrosion behavior of Mg60Zn20Yb15.7Ca2.6Sr1.7 alloy proposed for medical applications. The microstructure of the alloy in a form of high-pressure die-casted plates was presented using scanning electron microscopy in the backscattered electrons (BSEs) mode with energy-dispersive X-ray spectrometer (EDX) qualitative analysis of chemical composition. The crystallization mechanism and thermal properties were described on the basis of differential scanning calorimetry (DSC) results. The corrosion behavior of Mg60Zn20Yb15.7Ca2.6Sr1.7 alloy was analyzed by electrochemical studies with open circuit potential (EOCP) measurements and polarization tests. Moreover, light microscopy and X-ray photoelectron spectroscopy were used to characterize the corrosion products formed on the surface of studied samples. On the basis of the results, the influence of the cooling rate on the improvement in the corrosion resistance was proved. The presented studies are novel and important from the point of view of the impact of the technology of biodegradable materials on corrosion products that come into direct contact with the tissue environment.Inconel 738LC (IN738LC) is a nickel-based superalloy specially used in the hot section components of turbine engines. One of its main drawbacks relies on the cracking susceptibility when it is manufactured by laser powder bed fusion (LPBF). This paper analyzes the influence of minor alloying element concentration on cracking tendency of IN738LC superalloy manufactured by LPBF. For that objective, samples were manufactured using two powders, which presented different minor alloying elements concentration (Si, Zr and B). It was shown that the samples crack tendency was very different depending on the powder used for their manufacturing. In fact, the measured crack density value was 2.73 mm/mm2 for the samples manufactured with the powder with higher minor alloying elements concentration, while 0.25 mm/mm2 for the others. Additionally, a special emphasis has been put on elemental composition characterization in cracked grain boundaries in order to quantify possible Si or Zr enrichment. It has been also studied the differences of solidification ranges and grain structures between both samples as a consequence of different minor alloying elements concentration in order to analyze their effect on crack susceptibility. In this sense, Scheil-Gulliver simulation results have shown that samples with higher Si and Zr contents presented higher solidification range temperature. This fact, as well as an increase of the presence of high angle grain boundaries (HAGB), leaded to an increment in the crack formation during solidification. Therefore, in this research work, an understanding of the factors affecting crack phenomenon in the LPBF manufactured IN738LC was accomplished.Oxide dispersion strengthened ferritic steel is considered an important structural material in fusion reactors due to its excellent resistance to radiation and oxidation. Fine and dispersed oxides can be introduced into the matrix via the powder metallurgy process. In the present study, large grain sizes and prior particle boundaries (PPBs) formed in the FeCrAlY alloy prepared via powder metallurgy. Thermo-mechanical treatment was conducted on the FeCrAlY alloy. Results showed that microstructure was optimized the average grain diameter decreased, the PPBs disappeared, and the distribution of oxides dispersed. Both ultimate tensile strength and elongation improved, especially the average elongation increased from 0.5% to 23%.Since the popularization of press hardening in the early noughties, die and tooling systems have experienced considerable advances, with tool refrigeration as an important focus. However, it is still complicated to obtain homogeneous cooling and avoid hot spot issues in complex geometries. Additive Manufacturing allows designing cavities inside the material volume with little limitation in terms of channel intersection or bore entering and exit points. In this sense, this technology is a natural fit for obtaining surface-conforming cooling channels an attractive prospect for refrigerated tools. This work describes a pilot experience in 3D-printed press hardening tools, comparing the performance of additive manufactured Maraging steel 1.2709 to conventional wrought hot work tool steel H13 on two different metrics durability and thermal performance. For the first, wear studies were performed in a controlled pilot plant environment after 800 hot stamping strokes in an omega tool configuration. On the second, a demonstrator tool based on a commercial tool with hot spot issues, was produced by 3D printing including surface-conformal cooling channels. This tool was then used in a pilot press hardening line, in which tool temperature was analyzed and compared to an equivalent tool produced by conventional means. Results show that the Additive Manufacturing technologies can be successfully applied to the production of press hardening dies, particularly in intricate geometries where new cooling channel design strategies offer a solution for hot spots and inhomogeneous thermal loads.Polymer composites containing carbon nanofillers are extensively developed for electromagnetic shielding applications, where lightweight and flexible materials are required. One example of the microwave absorbers can be thermoplastic fibers fabricated from copolyamide hot melt adhesives and 7 wt% of multi-walled carbon nanotubes, as presented in this paper. A broadband dielectric spectroscopy confirmed that the addition of carbon nanotubes significantly increased microwave electrical properties of the thin (diameter about 100 μm) thermoplastic fibers. Moreover, the dielectric properties are improved for the thicker fibers, and they are almost stable at the frequency range 26-40 GHz and not dependent on the temperature. The variances in the dielectric properties of the fibers are associated with the degree of orientation of carbon nanotubes and the presence of bundles, which were examined using a high-resolution scanning microscope. Analyzing the mechanical properties of the nanocomposite fibers, as an effect of the carbon nanotubes addition, an improvement in the stiffness of the fibers was observed, together with a decrease in the fibers’ elongation and tensile strength.Interactive display is an important part of electronic devices. It is widely used in smartphones, laptops, and industrial equipment. To achieve 3-dimensional detection, the piezoelectric touch panel gains great popularity for its advantages of high sensitivity, low cost, and simple structure. In order to help readers understand the basic principles and the current technical status, this article introduces the work principles of the piezoelectric touch panel, widely-used piezoelectric materials and their characteristics, as well as the applications of the piezoelectric touch panel. The challenges and future trends are also discussed.This article presents the influence of machining conditions on typical process performance indicators, namely cutting force, specific cutting energy, cutting temperature, tool wear, and fine dust emission during dry milling of CFRPs. The main goal is to determine the machining process window for obtaining quality parts with acceptable tool performance and limited dust emission. For achieving this, the cutting temperature was examined using analytical and empirical models, and systematic cutting experiments were conducted to assess the reliability of the theoretical predictions. A full factorial design was used for the experimental design. The experiments were conducted on a CNC milling machine with cutting speeds of 10,000, 15,000, and 20,000 rpm and feed rates of 2, 4, and 6 µm/tooth. Based on the results, it was ascertained that spindle speed significantly affects the cutting temperature and fine particle emission while cutting force, specific cutting energy, and tool wear are influenced by the feed rate. The optimal conditions for cutting force and tool wear were observed at a cutting speed of 10,000 rpm. The cutting temperature did not exceed the glass transition temperature for the cutting speeds tested and feed rates used. The fine particles emitted ranged from 0.5 to 10 µm aerodynamic diameters with a maximum concentration of 2776.6 particles for those of 0.5 µm diameters. Finally, results of the experimental optimization are presented, and the model is validated. The results obtained may be used to better understand specific phenomena associated with the milling of CFRPs and provide the means to select effective milling parameters to improve the technology and economics of the process.Liquid metals, such as Ga and eutectic Ga-In, have been extensively studied for various applications, including flexible and wearable devices. For applying liquid metal to electronic devices, interconnection with the various metal electrodes currently in use, and verifying their mechanical reliability are essential. Here, detailed investigations of the formation and growth of intermetallic compounds (IMCs) during the reactions between liquid Ga and solid nickel were conducted. Ga and Ni were reacted at 250, 300, and 350 °C for 10-240 min. The IMC double layer observed after the reactions contained a Ga7Ni3 bottom layer formed during the reactions, and a GaxNi top layer (with 89-95 at.% of Ga) precipitated during cooling. Numerous empty channels exist between the rod-type Ga7Ni3 IMCs. Ga7Ni3 growth occurred only in the vertical direction, without lateral coarsening and merging between the rods. The time exponents were measured at 1.1-1.5, implying that the reaction kinetics were near-interface reaction-controlled. The activation energy for Ga7Ni3 growth was determined as 49.1 kJ/mol. The experimental results of the Ga-Ni reaction study are expected to provide important information for incorporating liquid metals into electronic devices in the future.In the present study, 0.115 M L-arginine (LA) has been used as an eco-friendly inhibitor in simulated concrete pore solutions (SP-0) in order to form passive films on a steel rebar-solution interface until 144 h. Hence, 0.51 (SP-1) and 0.85 M NaCl (SP-2) were added in LA containing SP-0 solution to breakdown the passive film and to initiate corrosion reactions. The electrochemical results show that the charge transfer resistance (Rct) of steel rebar exposed to SP-1 and SP-2 solutions increased with respect to immersion periods. The sample exposed to the SP-2 solution initiated the corrosion reaction at the steel rebar-solution interface after 24 h of NaCl addition and formed pits; on the other hand, the sample without NaCl added, i.e., SP-0, showed agglomeration and dense morphology of corrosion products.This work presents an OsRu-based electrocatalyst synthesis, by a rapid and efficient method through microwave irradiation. The outstanding electrocatalyst shows a dual catalytic activity, demonstrating both hydrogen oxidation and oxygen reduction reactions. The material is structural and morphologically characterized by FT-IR, X-ray diffraction, EDS, and SEM, indicating nanoparticulated Os and Ru metallic phases with a crystallite size of ∼6 nm, calculated by the Scherrer equation. The metal nanoparticles are apparently deposited on a carbonaceous sponge-like morphology structure. Its electrochemical characterization is performed in 0.5 M H2SO4 by the rotating disk electrode technique, employing cyclic and linear sweep voltammetry. Two different ink treatments have been studied to improve the obtained polarization curves. The material is also tested in the presence of methanol for the oxygen reduction reaction, showing an important resistance to this contaminant, making it viable for its use in direct methanol fuel cells (DMFCs) as a cathode and in polymer electrolyte fuel cells (PEMFCs) as an anode as much as a cathode.In this report, the heating efficiencies of γ-Fe2O3 and hybrid γ-Fe2O3-TiO2 nanoparticles NPs under an alternating magnetic field (AMF) have been investigated to evaluate their feasible use in magnetic hyperthermia. The NPs were synthesized by a modified sol-gel method and characterized by different techniques. X-ray diffraction (XRD), Mössbauer spectroscopy and electron microscopy analyses confirmed the maghemite (γ-Fe2O3) phase, crystallinity, good uniformity and 10 nm core sizes of the as-synthesized composites. SQUID hysteresis loops showed a non-negligible coercive field and remanence suggesting the ferromagnetic behavior of the particles. Heating efficiency measurements showed that both samples display high heating potentials and reached magnetic hyperthermia (42 °C) in relatively short times with shorter time (~3 min) observed for γ-Fe2O3 compared to γ-Fe2O3-TiO2. The specific absorption rate (SAR) values calculated for γ-Fe2O3 (up to 90 W/g) are higher than that for γ-Fe2O3-TiO2 (~40 W/g), confirming better heating efficiency for γ-Fe2O3 NPs. The intrinsic loss power (ILP) values of 1.57 nHm2/kg and 0.64 nHm2/kg obtained for both nanocomposites are in the range reported for commercial ferrofluids (0.2-3.1 nHm2/kg). Finally, the heating mechanism responsible for NP heat dissipation is explained concluding that both Neel and Brownian relaxations are contributing to heat production. Overall, the obtained high heating efficiencies suggest that the fabricated nanocomposites hold a great potential to be utilized in a wide spectrum of applications, particularly in magnetic photothermal hyperthermia treatments.Tool wear and breakage detection technologies are of vital importance for the development of automatic machining systems and improvement in machining quality and efficiency. The monitoring of integral spiral end milling cutters, however, has rarely been investigated due to their complex structures. In this paper, an image acquisition system and image processing methods are developed for the wear and breakage detection of milling cutters based on machine vision. The image acquisition system is composed of three light sources and two cameras mounted on a moving frame, which renders the system applicable in cutters of different dimensions and shapes. The images captured by the acquisition system are then preprocessed with denoising and contrast enhancing operations. The failure regions on the rake face, flank face and tool tip of the cutter are extracted with the Otsu thresholding method and the Markov Random Field image segmentation method afterwards. Eventually, the feasibility of the proposed image acquisition system and image processing methods is demonstrated through an experiment of titanium alloy machining. The proposed image acquisition system and image processing methods not only provide high quality detection of the integral spiral end milling cutter but can also be easily converted to detect other cutting systems with complex structures.Friction is often accompanied by local fracture at the boundary of contacting bodies. The space between contacting bodies usually contains moving particles of a different nature, and a change in the effective friction conditions can be associated with a change in the structure of the contact area. This paper presents a new series of experiments where balls simulated the particles of the intermediate layer interacting with an elastic layer of different thickness. The effects of regularization when the balls approached each other were investigated considering different initial configurations (line and spatial structure). The balls simulated the particles of the intermediate layer interacting with the elastic layer of different thickness. The opposite effects of convergence and separation of the balls were observed in different experiments. A model of mutual effect during the contact of two balls with a two-layered elastic half-space was developed. An analysis of tangential forces due to the mutual effect was performed for different layer thicknesses, its relative compliance, and different distances between the balls. It was found that the input parameters defined the sign of the tangential force, which led to the convergence or the separation of the balls. The results can be used to create structures controlling the motion in the intermediate layer.The effect of heat treatment on the adsorptive capacity of a Brazilian palygorskite to remove the dyes crystal violet (CV) and congo red (CR) was investigated. The natural palygorskite was calcined at different temperatures (300, 500 and 700 °C) for 4 h. Changes in the palygorskite structure were evaluated using X-ray diffraction, X-ray fluorescence, thermogravimetric and differential thermal analysis, N2 adsorption/desorption and Fourier transform infrared spectroscopy. The adsorption efficiency of CV and CR was investigated through the effect of initial concentration, contact time, temperature, pH and dosage of adsorbent. The calcination increased the adsorption capacity of palygorskite, and the greatest adsorption capacity of CV and CR dyes occurred in the sample calcined at 700 °C (Pal-700T). The natural and calcined samples at 300 and 500 °C followed the Freundlich isothermal model, while the Pal-700T followed the Langmuir isothermal model. Adsorption kinetics results were well described by the Elovich model. Pal-700T showed better adsorption performance at basic pH, with removal greater than 98%, for both dyes. Pal-700T proved to be a great candidate for removing cationic and anionic dyes present in water.The melt temperature of aluminum alloys plays a significant role in determining the microstructure characteristic during continuous rheo-extrusion. However, it is difficult to measure the actual melt temperature in the roll-shoe gap. In this work, based on the basic theory of heat transfer, a calculation model for heat transfer coefficient of cooling water/roll interface and melt/roll interface is established. In addition, the relationship between the temperature at the melt/roll interface and the velocity of cooling water is investigated. Combined with the CALPHAD calculation, the melt temperature during solidification in the continuous rheo-extrusion process is calculated. Using this model, the cooling rate of an Al-6Mg (wt.%) alloy melt prepared by continuous rheo-extrusion is estimated to be 10.3 K/s. This model used to determine the melt parameters during solidification provides a reference for optimizing the production process of continuous rheo-extrusion technology.Ice formation on the aerodynamic surfaces of an aircraft is regarded as a major problem in the aerospace industry. Ice accumulation may damage parts, sensors and controllers and alter the aerodynamics of the airplane, leading to a range of undesired consequences, including flight delays, emergency landings, damaged parts and increased energy consumption. There are various approaches to reducing ice accretion, one of them being the application of icephobic coatings. In this work, commercially available polyurethane-based coatings were modified and deposited on NACA 0012 aircraft airfoils. A hybrid modification of polyurethane (PUR) topcoats was adopted by the addition of nanosilica and three-functional spherosilicates (a variety of silsesqioxane compound), which owe their unique properties to the presence of three different groups. The ice accretion on the manufactured nanocomposites was determined in an icing wind tunnel. The tests were performed under three different icing conditions glaze ice, rime ice and mixed ice. Furthermore, the surface topography and wetting behavior (static contact angle and contact angle hysteresis) were investigated. It was found that the anti-icing properties of polyurethane nanocomposite coatings strongly depend on the icing conditions under which they are tested. Moreover, the addition of nanosilica and spherosilicates enabled the reduction of accreted ice by 65% in comparison to the neat topcoat.In this work, for the first time, the influence of scaling up the process of titanium dioxide nanotube (TiO2NT) synthesis on the photoelectrochemical properties of TiO2 nanotubes is presented. Titanium dioxide nanotubes were obtained on substrates of various sizes 2 × 2, 4 × 4, 5 × 5, 6 × 6, and 8 × 8 cm2. The electrode material was characterized using scanning electron microscopy as well as Raman and UV-vis spectroscopy in order to investigate their morphology, crystallinity, and absorbance ability, respectively. The obtained electrodes were used as photoanodes for the photoelectrochemical water splitting. The surface analysis was performed, and photocurrent values were determined depending on their place on the sample. Interestingly, the values of the obtained photocurrent densities in the center of each sample were similar and were about 80 µA·cm2. The results of our work show evidence of a significant contribution to wider applications of materials based on TiO2 nanotubes not only in photoelectrochemistry but also in medicine, supercapacitors, and sensors.In the study, experiments were performed on two eco-efficient self-compacting concrete mixes of reduced binder content containing supplementary cementitious materials. The behaviour of the eco-efficient self-compacting concrete (SCC) mixture was examined to determine whether it is suitable for multilayer casting. It is recommended that the SCC should be poured in an uninterrupted manner. However, it is not uncommon that contractors are forced to take breaks as a result of delivery delays. Casting the elements in multiple poorly prepared layers may cause the creation of cold joints between them. Two technological variants of the multilayer casting of eco-efficient SCC on beam elements were analysed pouring the mixture from a minor height on the previously placed layer and placing the subsequent layer on the mechanically disturbed surface of the underlying material. Different delay times were used 15, 30, 45 and 60 min between the execution of two layers of eco-efficient SCC. The load-bearing capacity of the joint was determined using a splitting tensile strength test on cubic elements. It was observed that, regardless of the mixture and casting variant, the interlayer bond strength decreased as the delay time increased. This effect was less pronounced when the first layer was mechanically disturbed. It was also demonstrated that concrete with reduced binder content is characterized by a lower drop in bond strength between successive layers. Finally, it is noted that the current recommendations and normative guidelines for the multilayer casting of self-compacting concrete should be specified with regard to the time delay allowed for the execution of the next layer in the absence of interference with the previously placed layer. Lack of clarity in this respect may result in the creation of a cold joint and hence a reduction in the load-bearing capacity between layers.Photocatalysis application is considered as one of the most highly promising techniques for the reduction in wastewater pollution. However, the majority of highly efficient photocatalyst materials are obtained as fine powders, and this causes a lot of photocatalyst handling and reusability issues. The concept of the floating catalyst proposes the immobilization of a photocatalytic (nano)material on relatively large floating substrates and is considered as an encouraging way to overcome some of the most challenging photocatalysis issues. The purpose of this study is to examine floating photocatalyst application for Salmonella typhimurium bacteria inactivation in polluted water. More specifically, high-density polyethylene (HDPE) beads were used as a photocatalyst support for the immobilization of carbon-doped TiO2 films forming floating photocatalyst structures. Carbon-doped TiO2 films in both amorphous and anatase forms were deposited on HDPE beads using the low-temperature magnetron sputtering technique. Bacteria inactivation, together with cycling experiments, revealed promising results by decomposing more than 95% of Salmonella typhimurium bacteria in five consecutive treatment cycles. Additionally, a thorough analysis of the deposited carbon-doped TiO2 film was performed including morphology, elemental composition and mapping, structure, and depth profiling. The results demonstrate that the proposed method is a suitable technique for the formation of high-quality photocatalytic active films on thermal-sensitive substrates.Dynamic light scattering (DLS) is a popular method of particle size measurement, but at ultra-low particle concentrations, the occurrence of number concentration fluctuations limits the use of the technique. Number fluctuations add a non-Gaussian term to the scattered light intensity autocorrelation function (ACF). This leads to an inaccurate particle size distribution (PSD) being recovered if the normal DLS analysis model is used. We propose two methods for inverting the DLS data and recovering the PSDs when number fluctuations are apparent. One is to directly establish the relationship between the non-Gaussian ACF and the PSD by the kernel function reconstruction (KFR) method while including the non-Gaussian term to recover the PSD. The other is to remove the effect of the non-Gaussian term in the ACF by the baseline reset (BR) method. By including the number fluctuation term, the ideal recovered PSD can be obtained from the simulated data, but this will not happen in the experimental measurement data. This is because the measured intensity ACF contains more noise than the simulated ACF at ultra-low concentration. In particular, the baseline noise at the tail of long delay time of ACF overwhelms the number fluctuation term, making it difficult to recover reliable PSD data. Resetting the baseline can effectively remove the digital fluctuation term in ACF, which is also a feasible method to improve PSD recovery under ultra-low concentration. However, increasing noise at ultra-low concentrations can lead to errors in determining an effective baseline. This greatly reduces the accuracy of inversion results. Results from simulated and measured ACF data show that, for both methods, noise on the ACF limits reliable PSD recovery.Wave power marine concrete structures generate electrical energy using waves. They are exposed to a multi-deterioration environment because of air and hydrostatic pressure and chloride attack. In this study, the effect of air pressure repeatedly generated by water level change of wave power marine concrete structures on the chloride-ion diffusion of marine concrete was analyzed. The chloride-ion diffusion of wave power marine concrete structures was evaluated. The results show that the air chamber and bypass room, which were subjected to repetitive air pressures caused by water level changes, showed a higher water-soluble chloride-ion content compared to the generator room and docking facility, which were subjected to atmospheric pressure. Field exposure tests and indoor chloride attack tests were performed using fabricated specimens to analyze the effect of pressure on chloride-ion penetration. It was confirmed that Portland blast furnace slag had a greater inhibitory effect on chloride-ion penetration than ordinary Portland cement. The concrete specimens subjected to pressure showed increased capillary pores and micro-cracks. We devised an equation for calculating the diffusion coefficient based on measured data and estimating the diffusion coefficient for the location receiving repeated air pressure by using the diffusion coefficient of the location receiving general atmospheric pressure.This work intends to contribute to the understanding of the influence factors of early hydration of ultrafine cement by focusing on the different fineness, different kinds of hardening accelerators, and different curing temperatures. Isothermal calorimetry, thermogravimetry, and X-ray diffraction (XRD) were performed to compare the hydration and chemical evolution of pastes containing accelerators with different fineness and curing temperatures; meanwhile, mechanical properties and water absorption were tested. The results showed that the cement fineness had a significant effect on the early hydration process; the smaller the cement particle size, the higher the early compressive strength. The 24 h compressive strength of ultrafine cement with a particle diameter of 6.8μm could reach 55.94 MPa, which was 118% higher than the reference cement. Water absorption test results indicated that adding 1% Ca(HCOO)2 to ultrafine cement can effectively reduce the water absorption, and it was only 1.93% at 28 d, which was 46% lower than the reference cement. An increase in curing temperature accelerated the activation of ultrafine cement in terms of the strength development rate, and the content of Ca(OH)2 in the ultrafine cement paste could reach 13.09% after being mixed with water for 24 h, which was 22% higher than that of the reference cement.Using butyl titanate and absolute ethanol as raw materials, TiO2 was prepared by a hydrothermal method with different hydrothermal times, and the influences of hydrothermal time on the structure and photocatalytic performance of TiO2 were investigated. The obtained samples were characterized by XRD, SEM, TEM, BET, PL and DRS, separately. The results show that TiO2 forms anatase when the hydrothermal time is 12 h, forms a mixed crystal composed of anatase and rutile when the hydrothermal time is 24 h, and forms rutile when the hydrothermal time is 36 h. With the extension of hydrothermal time, anatase gradually transforms into rutile and the surface area decreases. Although TiO2-24 h and TiO2-36 h show lower photoinduced charge recombination and higher light source utilization, TiO2-12 h exhibits the highest photocatalytic activity owing to its largest surface area (145.3 m2/g). The degradation degree of rhodamine B and tetracycline hydrochloride reach 99.6% and 90.0% after 45 min.This work reports the effects of free volume on curcumin release in various polymer-based composite films. Curcumin-reinforced biocomposite films were fabricated with natural biopolymers (carrageenan and chitosan) and bioplastics (poly(lactide) (PLA) and poly (butylene adipate-co-terephthalate) (PBAT)) via the solvent casting method. The curcumin release test was performed using an aqueous medium, and it was found that it was released the fastest in the carrageenan film, followed by the chitosan, PLA, and PBAT films, presumably owing to the dissimilarity of the polymer matrix. The free volume of the polymer films was determined using positron annihilation lifetime spectroscopy (PALS) to understand the release phenomena of curcumin. The free volume fraction was varied and reliant on the type of polymer, with the highest in the PBAT-based film followed by the PLA-, chitosan-, and carrageenan-based films. The free volume method helps analyze the release of bioactive compounds in a polymer matrix and may help to achieve a better understanding of the release of bioactive compounds.Waste glass constitutes a significant part of general waste worldwide. Unfortunately, only a small percentage is recycled. It is, therefore, quite important that it can be applied in the production of construction materials. The main aim of this article is to determine the thermal conductivity of the products modified with granulated foam glass (GFG) (recycled product) of the 0.25-0.5 mm fraction, as well as to indicate dependence of the change in volume density of samples caused by the use of GFG and the change of the thermal conductivity coefficient compared to reference samples. For the purpose of this research, various parameters were examined i.a. volume density, water absorption, determination of the pore size distribution by mercury porosimetry and determination of the heat conduction coefficient with the use of a plate apparatus. The test results were developed on the basis of a mathematical model that determined the influence of the filler on the functional properties of the product. The research has shown that the use of GFG in the sand-lime products will contribute to lowering their thermal conductivity by more than 50% compared to traditional products.Accurate prediction and control of the steel plate temperature in the laminar cooling process are very challenging. In this research, an experimental platform was built to measure the heat transfer characteristics of the steel plate in the process of matrix laminar spray cooling when the steel plate is one millimeter away from the upper surface. The „buried couple method” was used, including the cooling temperature and cooling rate. Then, the temperature and the integrated heat transfer coefficient at the steel plate surface were calculated by the time-sequential function method (TSFM). The obtained results show that the fast cooling stage under the water cooling condition occurred in the first 1.5 s, and the measuring point temperature decreased by 8%. The „re-reddening” phenomenon of the steel plate appeared with time, and the measuring point temperature increased by 37%. Second, the maximum calculated difference between the surface temperature and the measuring point temperature was 0.75 °C, and the integrated heat transfer coefficient conformed to the periodic boundary features. The comprehensive convective heat transfer coefficient on the surface was in agreement with the periodic boundary characteristics, and its value exhibited oscillatory attenuation with the cooling process, and the oscillatory peak period was about 6 seconds. Two methods, sequential function method (SFM) and finite difference method (FDM), were used to verify the correctness of TSFM.Nano-ridge engineering (NRE) is a novel method to monolithically integrate III-V devices on a 300 mm Si platform. In this work, NRE is applied to InGaP/GaAs heterojunction bipolar transistors (HBTs), enabling hybrid III-V/CMOS technology for RF applications. The NRE HBT stacks were grown by metal-organic vapor-phase epitaxy on 300 mm Si (001) wafers with a double trench-patterned oxide template, in an industrial deposition chamber. Aspect ratio trapping in the narrow bottom part of a trench results in a threading dislocation density below 106∙cm-2 in the device layers in the wide upper part of that trench. NRE is used to create larger area NRs with a flat (001) surface, suitable for HBT device fabrication. Transmission electron microscopy inspection of the HBT stacks revealed restricted twin formation after the InGaP emitter layer contacts the oxide sidewall. Several structures, with varying InGaP growth conditions, were made, to further study this phenomenon. HBT devices-consisting of several nano-ridges in parallel-were processed for DC and RF characterization. A maximum DC gain of 112 was obtained and a cut-off frequency ft of ~17 GHz was achieved. These results show the potential of NRE III-V devices for hybrid III-V/CMOS technology for emerging RF applications.Lithium-ion batteries (LiBs) are seen as a viable option to meet the rising demand for energy storage. To meet this requirement, substantial research is being accomplished in battery materials as well as operational safety. LiBs are delicate and may fail if not handled properly. The failure modes and mechanisms for any system can be derived using different methodologies like failure mode effects analysis (FMEA) and failure mode methods effects analysis (FMMEA). FMMEA is used in this paper as it helps to identify the reliability of a system at the component level focusing on the physics causing the observed failures and should thus be superior to the more data-driven FMEA approach. Mitigation strategies in LiBs to overcome the failure modes can be categorized as intrinsic safety, additional protection devices, and fire inhibition and ventilation. Intrinsic safety involves modifications of materials in anode, cathode, and electrolyte. Additives added to the electrolyte enhance the properties assisting in the improvement of solid-electrolyte interphase and stability. Protection devices include vents, circuit breakers, fuses, current interrupt devices, and positive temperature coefficient devices. Battery thermal management is also a protection method to maintain the temperature below the threshold level, it includes air, liquid, and phase change material-based cooling. Fire identification at the preliminary stage and introducing fire suppressive additives is very critical. This review paper provides a brief overview of advancements in battery chemistries, relevant modes, methods, and mechanisms of potential failures, and finally the required mitigation strategies to overcome these failures.Aiming at the problem of the poor plasticity of magnesium alloy leading to serious edge cracks in the rolling process, this paper conducts a systematic study on the crack suppression mechanism of rolling under different thickness reductions. Using restricted rolling and conventional rolling, comparing the microstructure evolution of the plate after rolling, and combining the information of the simulated temperature field and stress field of the plates, the behavior of twins and dislocations under different thickness reductions is explained, and the influence of serious damage caused by single-pass hot rolling of magnesium alloy is explored. The compressive stress fields along with the transverse and normal directions under restricted rolling cause the compression twins to mature into secondary twins under rolling with small thickness reduction and induce a large number of tensile twins when the thickness reduction amount is increased. The multiple slips activated by the higher temperature field at the edge of the small thickness reduction amount cause dislocations to be distributed inside and outside the twins, while the edge with large thickness reduction can activate more slip due to the high-temperature field resulting from friction, resulting in the twin be destroyed.Achieving magnesium-rare earth alloys with excellent mechanical properties remains a challenging goal in the aerospace industry. The integrated extrusion and equal channel angular pressing were employed to refine grain and improve the mechanical properties of Mg-xNd-2.0Sm-0.4Zn-0.4Zr alloys. The effect of Nd element on microstructure and mechanical properties of the extruded and subsequently aged alloys were carried out by varying the amount of the Nd element from 0 wt.% to 2.5 wt.%. The optical microscopy results indicated that the grain size was remarkably refined by the addition of Nd element. The grain size decreased from 29.7 μm to 10.9 μm with increasing of the Nd element from 0 wt.% to 2.5 wt.%. The transmission electron microscopy results showed that the nano-scaled basal lamellar precipitates, prismatic lamellar precipitates and granular precipitates were formed in α-Mg matrix. The amount of the precipitates increased significantly by the addition of Nd. Moreover, the strength of the alloys significantly improved with Nd. Superior strength and considerable plasticity were obtained as the content of Nd element reached 2.0 wt.%, while the tensile strength of the Mg-2.0Nd-Sm-Zn-Zr alloy (315 ± 5 MPa) increased by 35.8% with respect to the Nd-free alloy (232 ± 3 MPa).Porous structures are of great importance in tissue engineering. Most scaffolds are 3D printed, but there is no single methodology to model these printed parts and to apply finite element analysis to estimate their mechanical behaviour. In this work, voxel-based and geometry-based modelling methodologies are defined and compared in terms of computational efficiency, dimensional accuracy, and mechanical behaviour prediction of printed parts. After comparing the volumes and dimensions of the models with the theoretical and experimental ones, they are more similar to the theoretical values because they do not take into account dimensional variations due to the printing temperature. This also affects the prediction of the mechanical behaviour, which is not accurate compared to reality, but it makes it possible to determine which geometry is stiffer. In terms of comparison of modelling methodologies, based on process efficiency, geometry-based modelling performs better for simple or larger parts, while voxel-based modelling is more advantageous for small and complex geometries.


