Preparation and Properties of Cornstarch Adhesives

Abstract: The main goal of this study was to use cornstarch in the production of environmentally sound adhesives. 'Three-formaldehyde glue' pollutes the environment and harms to human health strongly, which widely used for wood-based panels preparation. Environment-friendly cornstarch adhesives were prepared using method of oxidation-gelatinization, insteading of the three formaldehyde glue. The effects of the quality ratio of starch and water, temperature and shear rate on the apparent viscosity of the adhesive were studied. The rheological eigenvalue of apparent viscosity was studied through nonlinear regression. The results showed that the apparent viscosity of cornstarch adhesives increased and then decreased with the increasing of temperature and the maximum value was obtained at 10 o C; the apparent viscosity decreased slowly with the increasing of rotor speed; the phenomenon of shear thinning appeared wither cornstarch adhesives which was pseudo-plastic fluids. Cornstarch adhesives with characteristics of non-toxic, no smell and pollution could be applied in interior and upscale packaging

Electrophoretic deposition and laser cladding of bioglass coating on Ti

Bioglass coatings derived from electrophoretic deposition method were fused on Ti surface by laser cladding process using a continuous CO laser. The specimens were studied by field-emission scanning electron microscopy, X-ray diffraction and bonding tests. Titanium oxide layer with hierarchical structures consisting of submicron rows of leaf-like embossments and nano-pores was obtained by combining acid etching and anodization processes, which increased the surface roughness of Ti. When heat-treatment temperature was 700 °C and high, CaSiO phase began to crystallize from the bioglass matrix and the crystallinity reached its maximum at 700 °C. During the electrophoretic deposition process, porous bioglass coatings composed of bioglass particles and fibers were deposited on Ti surface. Bioglass coatings with similar hierarchical structure containing submillimeter bioglass beads and microfibers were synthesized on Ti surface by laser fusion. There are no obvious microcracks at the interface of the Ti-coating, which revealed the good bonding between Ti-porcelain. With the laser scanning distance decreased, the bond strength increased accordingly. After only one day immersion in SBF, calcium phosphate began to precipitate on the bioglass coating's surfaces. The thickness of the calcium phosphate precipitation and the amount of microparticles increased with immersion time

Electrochemical Impedance Spectroscopic Studies of the First Lithiation of Si/C Composite Electrode

The Si/C composite materials were prepared by ball milling method, and characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM). The result displayed that Si in the Si/C composite materials still maintained a good crystal structure and uniformly dispersed in carbon black matrix. The first discharge capacity was 3393 mAh/g, and 4 cycles later still retained 1000 mAh/g, showing better charge-discharge cycle performance. Electrochemical impedance spectroscopy test indicated that there appeare three semicircles respectively representing the impedance of contact problems, solid electrolyte interface film (SEI film), charge transfer and phase transformation in the first lithiation, and their evolutive principles were also investigated

A comparative photocatalytic study of TiO2 loaded on three natural clays with different morphologies

[EN] In this work, a sol-gel method was used to load TiO2 nanoparticles on three clays (kaolinite, halloysite and palygorskite) with different morphologies (plates, tubes, and rods with micro tunnels), and then the photocatalytic performance of obtained clay-TiO2 composites for degradation of methyl orange was comparatively investigated. The results surprisingly show that the trend of photocatalytic performance of composites is opposite to that of special surface area of corresponding clays. By concentrated analysis of the loading status of TiO2, the lowest photocatalytic efficiency of palygorskite-TiO2 composite is mainly ascribed to (1) the aggregation of TiO2 nanoparticles on Pal surface, not the amount of TiO2 and (2) the relatively weak adsorption of Pal to methyl orange. The additional adsorption of hydroxyl surface of Kaol to methyl orange and little TiO2 in the lumen of Hal tube leads to the better photocatalytic performance of kaolinite-TiO2 composite than halloysite-TiO2 composite. Finally, kaolinite is proved to be an excellent carrier to support nano TiO2 resulting in a good photocatalytic performance and cycle stability, and the study can provide a direct guidance to select appropriate clay-photocatalyst composites for different practical applications.This work is supported by the National Natural Science Foundation of China (41502032) and the Fundamental Research Funds for the Central Universities (2019XKQYMS76).Wu, A.; Wang, D.; Wei, C.; Zhang, X.; Liu, Z.; Feng, P.; Ou, X.... (2019). A comparative photocatalytic study of TiO2 loaded on three natural clays with different morphologies. Applied Clay Science. 183:1-12. https://doi.org/10.1016/j.clay.2019.105352S11218

Effects of impact energy on the wear resistance and work hardening mechanism of medium manganese austenitic steel

Abstract Medium manganese austenitic steel (MMAS) fabricated through the hot rolling process has been used in the mining, military, and mechanical industries. In this paper, the abrasion performance and hardening mechanism were measured under a series of impact energies. The impact wear was tested at different impact energies from 0.5 J to 6 J using a dynamic load abrasive wear tester (MLD-10). Microstructure and surface morphologies were analyzed using scanning electron microscopy, X-Ray diffraction, and transmission electron microscopy. The results suggest that MMSA has the best wear resistance at 3.5 J and the worst wear resistance at 1.5 J. Furthermore, the wear mechanism and worn surface microstructure change with different impact energies. There are small differences between a large amount of martensite on the worn surfaces under different impact energies and the shapes of dislocation and twins change with different impact energies

Cost-Performance Analysis of Perovskite Solar Modules

99 p. // 15 - 29 : 0015El proceso de mantenimiento en una empresa garantiza la efectividad y eficiencia de las maquinas de tracción instaladas por la empresa Andino, un estudio detallado del histórico de fallas causadas por esta empresa, permitió estipular el método de mantenimiento que mejor se ajustara a las necesidades de la empresa, diseñando para ella un modelo de mantenimiento preventivo. La causa del retiro de aproximadamente el 7% de clientes en el último año, despertó una gran preocupación, aplicando herramientas como diagrama de causa efecto se encontró que las causas fueron las abundantes fallas en las máquinas de tracción y métodos para mantenerlas por efecto de su funcionamiento, por ello se generan nuevos elementos de control de tiempos de uso, como es la adaptación de un Horómetro para cada máquina de tracción, que aporta al personal de mantenimiento un dato real del uso y de esta manera los tiempos más apropiados para generar visitas de mantenimiento preventivo, reduciendo de manera sustancial los tiempos de parada de las máquinas y daños mayores en las mismas, se reduce también las horas hombre de los mecánicos, lo que se traduce en mayor eficiencia y satisfacción para el cliente

Sol–gel synthesis of TiO2-modified nanocomposite coatings on titanium

Titanium dioxide nanoparticles-modified nanocomposite coatings were synthesized on titanium by sol–gel process. The specimens were studied by differential scanning calorimetry, transmission electron microscopy, field-emission scanning electron microscopy and bonding tests. TEM results showed that TiO2 nanoparticles were adhered and enwrapped in the hybrid sol matrixes to form aggregates of TiO2 nanoparticles. The size of the particle aggregates increased from about 160\ua0nm to above 500\ua0nm with the content of the TiO2 particles increasing from 45 to 60\ua0ma%. At the same time, the quantities of the microcracks on the coating surface gradually decreased. The solid phase content of the sols was increased by the addition of TiO2 nanoparticles, which avoided the formation of microcracks on the coatings surface. Compared to the uncoated group, the highest bonding strength improvement of about 24\ua0% was obtained at the TiO2 content of 60 ma%. Graphical Abstract: [Figure not available: see fulltext.

Effect of laser parameters on the microstructure of bonding porcelain layer fused on titanium

Bonding porcelain layer was fused on Ti surface by laser cladding process using a 400 W pulse CO laser. The specimens were studied by field-emission scanning electron microscopy, X-ray diffraction and bonding tests. During the laser fusion process, the porcelain powders were heated by laser energy and melted on Ti to form a chemical bond with the substrate. When the laser scanning speed decreased, the sintering temperature and the extent of the oxidation of Ti surface increased accordingly. When the laser scanning speed is 12.5 mm/s, the bonding porcelain layers were still incomplete sintered and there were some micro-cracks in the porcelain. When the laser scanning speed decreased to 7.5 mm/s, vitrified bonding porcelain layers with few pores were synthesized on Ti

Surface modifications and Nano-composite coatings to improve the bonding strength of titanium-porcelain

Surface modifications of Ti and nano-composite coatings were employed to simultaneously improve the surface roughness, corrosion resistance and chemical bonding between porclain-Ti. The specimens were studied by field-emission scanning electron microscopy, surface roughness, differential scanning calorimetry, Fourier transform infrared spectroscopy, corrosion resistance and bonding strength tests. The SEM results showed that hybrid structures with micro-stripes, nano-pores and nano-protuberances were prepared by surface modification of Ti, which significantly enhanced the surface roughness and corrosion resistance of Ti. Porous nano-composite coatings were synthesized on Ti anodized with pre-treatment in 40% HF acid. TiO nanoparticles were added into the hybrid coating to increase the solid phase content of the sols and avoid the formation of microcracks. With the TiO content increasing from 45 wt% to 60 wt%, the quantities of the microcracks on the coating surface gradually decreased. The optimal TiO content for the nanocomposite coatings is 60 wt% in this research. Compared to the uncoated group, the bonding strength of the coated groups showed a bonding strength improvement of 23.96%. The cytotoxicity of the 4# coating group was ranked as zero, which corresponds to non-cytotoxicity

Direct Synthesis of Few-Layer F‑Doped Graphene Foam and Its Lithium/Potassium Storage Properties

Heteroatom-doped graphene is considered a potential electrode materials for lithium-ion batteries (LIBs). However, potassium-ion batteries (PIBs) systems are possible alternatives due to the comparatively higher abundance. Here, a practical solid-state method is described for the preparation of few-layer F-doped graphene foam (FFGF) with thickness of about 4 nm and high surface area (874 m²g^–1). As anode material for LIBs, FFGF exhibits 800 mAh·g^–1 after 50 cycles at a current density of 100 mA·g^–1 and 555 mAh·g^–1 after 100 cycles at 200 mA·g^–1 as well as remarkable rate capability. FFGF also shows 165.9 mAh·g^–1 at 500 mA·g^–1 for 200 cycles for PIBs. Research suggests that the multiple synergistic effects of the F-modification, high surface area, and mesoporous membrane structures endow the ions and electrons throughout the electrode matrix with fast transportation as well as offering sufficient active sites for lithium and potassium storage, resulting in excellent electrochemical performance. Furthermore, the insights obtained will be of benefit to the design of reasonable electrode materials for alkali metal ion batteries