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[en] The importance of fertilizers in boosting crop production has motivated the development of novel high-performance systems capable of improving the phosphorus release in the soil. For instance, methods capable of increasing the surface area of fertilizer particles and promoting the solubilization of low-solubility compounds, including phosphates, are highly pursued. This study was aimed at synthesizing hydroxyapatite nanoparticles and investigating their solubility in relation to crystallinity, size, and morphology for phosphorous fertilizer applications. To improve the phosphate ions release, the hydroxyapatite nanoparticles were storage in biodegradable sachets composed of thermoplastic starch/pectin blends with different polymer ratios. The results showed that the smallest and less crystalline hydroxyapatite nanoparticles presented the highest solubility. After storage in polymeric thermoplastic starch:pectin sachets, solubility for all samples was greatly improved, enhancing the phosphorus release due to pH decrease, independent on the nanoparticle size, shape, and crystallinity. The results highlight that the use of acidic sachets is a valuable approach for enhancing phosphorus and other macronutrients release from fertilizers with basic surface properties, aiming at increasing agricultural crop productivity. Graphical Abstract: .
[en] Full text: Recently, several researchers have studied about excellent properties of material. Furthermore, Researchers have been issued joining of heterogeneity materials that having different unique properties. Among joining of heterogeneity materials, joining technique of thermoplastics used generally using by low power of diode laser system. And, research to joining of plastic and metal have been studied these days. In existing method of bonding plastic, laser-beam is transmitted to the upper layer and lower layer absorbed laser-beam. And then, the absorbed laser-beam changes the heat energy and it characteristics strong bonding properties. However, when joining of metal and plastic, the joining force is weaker than the joining of plastic and plastic. So, we studied the joining characteristics and enhance adhesion of metal and plastic. First of all, we confirmed that a phenomenon of mutual between plastic and metal transmission joining The material used in the experiment is SUS(SUS316L) and PC(Polycarbonate). PC is thickness 5mm and have transmittance of 91%. SUS is thickness 2mm. Laser source has a wavelength of 1070nm, beam size 10mm, output power 79.57W. And the melting point(about 300℃) of the PC kept by adjustment of processing speed. In order to enhance excellent joining force, we experimented a number of ways such as reducing the gap between the each material, fine patterning surface of the SUS by femtosecond laser, surface texturing. So, the melted PC were tested to more sturdy attach to the joining surface of SUS. (author)
[en] The attenuation of acoustic emission (AE) waves was evaluated for injection-molded short-fiber-reinforced thermoplastic composites employing simulated AE waves. Values of attenuation coefficient (α) decreased more with increasing fiber volume fraction (V1) than that expected from a simple linear relation between α and V1. The effect of wave attenuation was taken into account in a quantitative analysis of the AE peak amplitude distribution which was obtained from each zone partitioned in a specimen gage portion. The amplitude distribution compensated for the measured attenuation loss was exhibited almost similar in every zone of the specimen. Consequently, it was, shown that the AE amplitudes obtained from fiber/plastic composites were considerably affected by the attenuation
[en] In the last 5-10 years the process of 3D printing has an incredible advanced in all the fields with a tremendous number of applications. Plastic materials exhibit highly beneficial mechanical properties while delivering complex designs impossible to achieve using conventional manufacturing. In this article the printing process (filling degree, time, complications and details finesse) of few plastic elements with complicated geometry and fine details was analyzed and comment. 3D printing offers many of the thermoplastics and industrial materials found in conventional manufacturing. The advantages and disadvantages of 3D printing for plastic parts are discussed. Time of production for an element with complex geometry, from the design to final cut, was evaluated. (paper)
[en] A process is described for fabrication of neutron shielding from thermoplastic plastic with incorporated neutron absorber with a proportion of more than 5%, in which the plastic is applied in prefabricated form on the surface to be protected, characterized by the fact that, for armored vehicles, the plastic prefabricated as plate or board is adapted during application to the surface to be protected by reforming the thermoplastic of the wall surface of the armored vehicle to be shielded
[en] Polymethylpentene, commonly referred to by its trade name TPX (Mitsui Chemicals, Inc.), is a thermoplastic polymer that has the potential to be a useful window material for dynamic compression experiments. For such experiments, an optically transparent or a low x-ray absorptive window is often used to maintain stress within the sample during compression. TPX can be used as a low-impedance optical and x-ray window due to its good transmittance in most parts of the electromagnetic spectrum, very low density (0.83 g/cm3), and low x-ray absorption. In dynamic compression experiments, interferometry can be used to determine the particle velocity at the interface between the sample and window. However, velocimetry measures the rate of change of the optical path length, commonly referred to as the apparent particle velocity. An experimentally determined window correction factor is needed to ascertain the actual particle velocity from the measured apparent velocity. Here, we present the results of a series of dynamic compression experiments from 1 to 31 GPa designed to characterize the mechanical and optical response of TPX, determine the range of stresses over which TPX is transparent, and determine the window correction factor. Finally, the index of refraction was found to be essentially linear in density, resulting in a simple constant correction factor. TPX was found to remain largely transparent over the entire stress range examined.
[en] We present a novel technique called electrical nano-imprint lithography (e-NIL) for topographic and electrostatic patterning of thermoplastic electret films at the nanometer scale. This versatile parallel process consists of simultaneously transferring micro- or nano-patterns from a conductive mold into a thermoplastic electret film and injecting positive or negative electrical charges into the bottom of the imprinted patterns. As proof of concept, we used this e-NIL process to fabricate arrays of 5 μm and 300 nm wide topographic charged patterns into polymethylmethacrylate (PMMA) thin films coated on silicon wafers. We demonstrated that these patterned PMMA films, exhibiting thousands of topographically confined and electrostatically active sites, can be used for high-throughput directed assembly of colloidal nanoparticles. (paper)
[en] Composite laminates reinforced by woven basalt fibers and based on different polymer matrices were prepared and mechanically characterized, in static and dynamic conditions, to compare the results and evaluate the influence of the matrix type. In this regard, a thermoplastic resin, polyamide 6 (PA6), and two thermosetting matrices, vinyl ester and epoxy grades, commonly used for high-performance applications, were considered. Indentation depth measurements carried out by a confocal microscope and ultrasound analyses performed on specimens subjected to falling dart tests at levels of impact energies lower than the perforation one permitted to evaluate the extent of plastic deformations and of subjected delaminations, respectively. These data have provided useful information about the involved damage mechanisms and highlighted interesting perspective of use for the eco-friendly thermoplastic sample.
[en] The viscoelastic behaviour of 3D printed samples produced from different types and contents of commercially produced filaments of wood and thermoplastics at different printing settings was investigated in this study. An Ares G2 rheometer was used to carry out the dynamic mechanical analysis (DMA) of the printed materials. A strain sweep and a temperature ramp test were made to evaluate the effect of 3D printing settings, materials, and temperature on the properties of the 3D-printed specimens. Five different printing materials (ABS, PLA, co-polyesters, mixtures with different wood content) and three printing layer thicknesses (0.09, 0.19, 0.29 mm) were used. The result showed that the specimens printed from Filament C (polymer blend of co-polyesters) had the lowest storage modulus while the highest modulus was found in the PLA based samples. When comparing pure PLA and PLA-wood filaments, the addition of wood particles decreased the storage modulus by 40%. The glass transition temperature (Tg) of the materials differed with each other. The specimens printed from ABS had the highest Tg 115 °C, followed by the specimens printed from co-polyester-based filament (around 70 °C), pure PLA, and PLA-wood filaments (64 °C–66 °C). The addition of wood did not change the glass transition temperature, since the main matrix was made of polymer. The viscoelastic behaviour of the 3D printed neat polymer and wood/polymer parts produced at different processing parameters and conditions can be considered for filament producers for material selection and the design engineers when wood/PLA printed parts fabricated through FDM technique. (paper)