Mechanical Grinding Method Research Articles

Photocatalytic study of methyl orange dye in UV exposure by using ZnO nanoparticles

The ZnO nanoparticles were prepared by mechanical grinding method of the laboratory grade powder. X-ray diffraction (XRD), Transmission electron microscope (TEM), Diffuse reflectance spectra (DRS) characterizations were done for the conformity of phase formation, particle size estimation and optical property study. XRD result shows ZnO nanoparticles are of hexagonal wurzite phase and TEM image shows the diameter and length of the nanoparticles are 59.34 nm and 300 nm respectively. DRS image shows the band edge absorption spectra is coming around 380 nm. The photocatalytic activity was investigated under the UV exposure using laboratory grade ZnO nanoparticles for the decomposition of Methyl Orange (MO) dye. The MO dye decomposition took 60 min for the complete decomposition of dye. The reaction rate and kinetics is also studied. The reaction rate constant is found to be 0.05 min−1 and also it follows pseudo-fast order reaction kinetics. These materials are low cost materials and showing excellent photocatalytic activity.

Crystal structure and anti-liver cancer activity of a new tetranuclear Zn complex with 2-ethoxy-6-methyliminomethyl-phenol

A new metal coordination complex [Zn(L)(N3)]4 (1) based on the Schiff base ligand 2-ethoxy-6-methyliminomethyl-phenol (HL) is successfully prepared via a slow evaporation method. The as-prepared metal complex is characterized by various physicochemical techniques, e.g. elemental analysis and X-ray single crystal diffraction. Furthermore, we use a mechanical grinding method to prepare nanosized crystalline complex 1 (nano-1). The anti-liver cancer activity of nano-1 is evaluated in vitro. Firstly, the cell viability and cell proliferation ability are assessed with CCK-8 and cell colony formation assay, respectively. In addition to this, the cell migration and invasion are also evaluated with the transwell assay after indicated treatment.

Retracted: A New Mixed‐Ligand Coordination Polymer: Crystal Structure, Molecular Docking and Alleviating Effect on Myocarditis by Inhibiting the NLRP3‐Caspase‐1 Pathway in Cardiomyocytes

AbstractA new mixed‐ligand coordination polymer {[Co(Hbidc)(2,2′‐bpy)(H2O)2]⋅1.5H2O}n (1) has been successfully prepared by the reaction of Co(NO3)2⋅6H2O, 2, 2′‐bipyridine (2,2′‐bpy) as well as benzimidazole‐5, 6‐dicarboxylic acid (H3bidc) in the mixed solvent of water and DMA under solvothermal conditions. Furthermore, a mechanical grinding method was used to produce the nanostructure 1 with the average size of 263 nm. The integrity of H9 C2 cardiomyocytes cell membrane after nano 1 treatment was detected by LDH detection. After nano 1 incubation, the inflammatory level in the H9 C2 cardiomyocytes was evaluated by western blot and ELISA measurement. In addition, the ROS accumulation in H9 C2 cardiomyocytes after nano 1 treatment was determined by H2DCFDA detection assay. Finally, possible interactions between the studied complex 1 and protein has been probed using molecular docking simulation.

Preparation of Nano-Cu-Fe Composite Metal Oxides via a Mechanical Grinding Method and Its Catalytic Performance for the Thermal Decomposition of Ammonium Perchlorate

ABSTRACT In this article, a series of nano-Cu-Fe composite metal oxides (nano CuO/Fe2O3), with different molar ratios of CuO/Fe2O3 (1:2, 1:1, 1:0.5, 1:0.25), were prepared in large-scale by mechanical grinding. The microstructures, surface elements and morphologies of samples are analyzed by X-ray diffraction (XRD), X-ray energy dispersive spectrometry (EDS), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). The catalytic effects of nano-Cu-Fe composite metal oxides on the thermal decomposition of ammonium perchlorate (AP) were investigated by thermogravimetric (TG) analysis and differential scanning calorimetric (DSC) techniques. The results show that nano-Cu-Fe composite metal oxides with the molar ratio of CuO/Fe2O3 = 1:2 have the best catalytic effect for AP thermal decomposition as compared to the other nano-Cu-Fe composite metal oxides, the single nano CuO, and nano Fe2O3. Also, the results show that the decomposition temperature of AP has fallen from 441.3°C to 355.3°C, whereas the decomposition heat has risen from 941 to 1749 J/g, which supports the existence of a synergistic effect between CuO and Fe2O3 nanoparticles.

Catalytic activity of nano-sized CuO on AP-CMDB propellant

ABSTRACTIn this work, nano-sized CuO prepared by mechanical grinding method was applied to the AP-CMDB propellant. The catalytic activity of nano-sized CuO on AP-CMDB propellant was investigated by thermogravimetric analysis/differential scanning calorimetric techniques. The combustion rates at atmospheric pressure of AP-CMDB propellant modified by nano-sized CuO were measured by strand burner method. The experimental results show enhancements on the thermal decomposition and combustion of AP-CMDB propellant in the presence of nano-sized CuO. Compared with blank propellant, the thermal decomposition temperature of AP-CMDB propellant shifts downward. Simultaneously, the combustion rate of AP-CMDB propellant at atmospheric pressure increases by about 22.2%. Encouragingly, the catalytic activity of nano-sized CuO on AP-CMDB propellant is superior to that of the bulk CuO, which leads to a potential application of nano-sized CuO in the AP-CMDB propellant.

Mechanical Properties of Rubber Sheets Produced by Direct Molding of Ground Rubber Tire Powder

The so called “direct powder molding” is a compressions molding process which can be directly applied to ground rubber tire (GRT). This study shows that the GRT can be re-used to produce medium-size parts with good mechanical properties without any addition of virgin rubber. For rubber sheets prepared from the mechanically ground rubber tire (MGRT) and the cryogenically ground rubber tire (CGRT), the densities and crosslink densities of the rubber sheets increased with a decrease of the particle size of the waste tire powder. The tensile strength of the rubber sheets increased with the decreasing of the particle size for the two types of waste tire powder to 250 μm and 120 μm, respectively, and then became level. The moulding pressure had no effect on the densities, tensile strength or elongation at break of the rubber sheets. These results suggested that the effect of the particle size is important and is correlated with the mechanical properties of the rubber sheets produced by direct powder moulding technology. In general, the best mechanical properties were obtained with waste tire rubber with a size of about 250 μm for the rubber particles obtained from the mechanical grinding method of waste tire powdering.

Effect of grinding method on the precursor powder of Bi2223 and properties of strip

In this paper, the two kinds of precursor powders of BiPb2212 and CaCuO2 were prepared by double powder method and an improved coprecipitation method, and then the BiPb2212 powders were fabricated by mechanical grinding and hand grinding. The BiPb2212 powders and CaCuO2 powders were prepared by two kinds of grinding methods mixed with a certain proportion of grinding, the Bi2223 superconducting tape with 37 filaments were prepared by removing the carbon, filling tube and annealing. The XRD analysis, SEM observation, laser particle size analysis and the tap density test of the precursor BiPb2212 powders were carried out respectively by mechanical grinding and hand-grinding. The results showed that the phase composition, microstructure, particle size distribution and tube density detection were all significant differences by using two kinds of grinding methods. Finally, the superconductivity test of the treated strip results show that the critical current from the field for the Bi2223 multi-core strip at 77K is improved from 86A (hand-grinding method) to 127A( mechanical grinding method). Therefore, the Bi2223 precursor powder by using mechanical grinding method is more conducive to obtain high-performance.

A new mechanism for improving electromagnetic properties based on tunable crystallographic structures of FeCoNiSi x Al0.4 high entropy alloy powders.

Mechanical grinding method was employed to prepare FeCoNiSixAl0.4 high entropy alloy powders, which present a simple solid solution structure (FCC and BCC). After annealing at 673 K, a large amount of BCC phase precipitate and a small amount of CoFe2O4 phase generate. The change of crystal structure may lead to an increase in Ms (from 100.3 emu g−1 to 124.2 emu g−1) and a decrease in Hc (from 107 Oe to 59.5 Oe for FeCoNiSi0.3Al0.4). The silica content has a significant effect on the electromagnetic parameters of the as-milled and as-annealed alloy powders, presenting the trend of first increase and then decrease. And the dielectric constant is obviously improved after annealing (e.g. from 8.48 to 11.21 and from 0.15 to 2.84 for the ε′ and ε′′ of FeCoNiSi0.3Al0.4 at 18 GHz, respectively), while the permeability is reduced. Compared with those of the as-milled samples, the μ′ of as-annealed FeCoNiSixAl0.4 (x = 0.1, 0.3, 0.4) remain unchanged or even increase due to the formation of CoFe2O4. Meanwhile, the relative content of the precipitated BCC to FCC for FeCoNiSi0.3Al0.4 enhance with the annealing temperature increase from 573 K to 773 K, and then reduce. And the ε′ and μ′ at 2 GHz present the same trend as the content ratio (ABCC/AFCC), while the ε′′ improve obviously after annealing, corresponding to the elevation of conductivity.

Fabrication and Analysis of Vanadium-Based Metal Powders for Selective Laser Melting

Vanadium Alloy is a type of advanced nuclear material with many ideal properties compared as traditional nuclear materials, which has very wide and important application in first-wall and blanket structural material for fusion power plant applications. So it has attracted increasing attentions, especially on new manufacturing methods, such as selective laser melting and so on. In this paper, the comparative study of the powders obtained by mechanical mixing method, dry grinding method and wet grinding method respectively was performed to evaluate the effect of ball milling process on the microstructure and degree of alloying of the vanadium-based powder mixtures with the nominal composition of V5Cr5Ti vanadium alloy. The powders prepared by dry grinding method exhibits better spherical-like morphology and degree of alloying than those prepared by mechanical mixing method and wet grinding method, which indicates that dry grinding method can be used to prepare the superfine vanadium alloy powders for selective laser melting. This work provides a new method as well as important insights into the preparation of superfine vanadium alloy powders for selective laser melting additive manufacturing technology.

NOxRemoval over V2O5/WO3–TiO2Prepared by a Grinding Method: Influence of the Precursor on Vanadium Dispersion

V2O5/WO3–TiO2 (VWT) catalysts for selective catalytic reduction (SCR) of NOx removal were prepared by a mechanical grinding method using different vanadium precursors. The SCR performances were evaluated in simulated flue gas and explained through characterizations by X-ray diffraction, X-ray photoelectron spectroscopy, Raman spectroscopy, H2 temperature-programmed reduction, and in situ diffuse reflectance Fourier transform spectroscopy. VO(acac)2–VWT catalyst prepared using a vanadyl acetylacetonate (VO(acac)2) precursor exhibited the highest catalytic activity and excellent resistance to SO2 and H2O poisoning in 200–400 °C compared to the catalysts obtained using other precursors. The VO(acac)2 precursor could enrich V on the surface remarkably and promote the formation and dispersion of polymeric vanadia species. Furthermore, a relatively high percentage of low-valent vanadium atoms were found on the VO(acac)2–VWT surface, facilitating electron transfer between V4+ and V5+. Surface-adsorbed NH3 species on VO(acac)2–VWT were much more reactive. The initial geometry of vanadium precursors determined the tendency of V to accumulate and further influenced the dispersion and final form of V species.

Mechanically ground softwood fines as a raw material for cellulosic applications

Utilization of mechanically manufactured lignocellulosic fines (LCNFs) was investigated in making filaments and films. The LCNFs particles were prepared by using a mechanical grinding method with a w-profile grinding stone that produces mostly fines with dimensions in the micrometer scale. The chemical and elemental composition of the w-stone ground LCNFs particles was investigated. It was found that the mechanically manufactured material exhibited the chemical structure of native wood. The LCNFs particles had an anionic surface charge making them colloidally semi-stable in water. The short length of the fines particles prevents their effective mechanical entanglement, which sets some limitations on preparation of filaments and films. Filament manufacturing required the use of a composite approach with carboxymethyl cellulose (CMC) as a binder polymer. The filament was manufactured by using dry-jet wet spinning with aluminium sulfate crosslinking. The chemical composition, crosslinking mechanism, and mechanical properties of the composite filaments were investigated. The composite approach with CMC was also used to prepare composite films with good mechanical performance. The investigated LCNFs material could be utilized in all-lignocomposite applications with cellulose derivatives, where biodegradability and biobased characteristics are desired properties.

Preserving Flake Size in an African Flake Graphite Ore Beneficiation Using a Modified Grinding and Pre-Screening Process

As the high value and the scarcity of large-flake graphite ore resources, it is in the best interest to maximize the amount of large flakes and minimize any processing that will reduce flake sizes. In the study, the mineralogy of an African graphite ore was estimated using X-ray diffraction (XRD), X-ray fluorescence (XRF), and optical microscope analyses. The results indicated that it was a heavily weathered large flake graphite ore and the main gangue minerals were quartz and kaolinite. The graphite flakes were thick, bent, and fractured, and some clay minerals were embedded into the graphite interlayer, which made it difficult to prevent the large flakes from being destroyed using mechanical grinding methods. An approach of steel rod coarse grinding and pebble regrinding effectively reduced the destruction of graphite flakes and improved the grinding efficiency. In addition, comparing with the conventional process, a pre-screening process was applied and the content of large flakes in the final concentrate was significantly improved.

Zn/Cu SORBENT SYNTHESIS FOR SYN-GAS PURIFICATION FROM HYDROGEN SULFIDE

The article is devoted to the synthesis of Zn/Cu sorbents and their study for the adsorption purification of synthesis gas from sulfur-containing compounds. The sorbents were synthesized using precipitation method, hydrothermal treatment, and mechanical grinding and microemulsion method. The article contains results of the physico-chemical studies of Zn/Cu sorbents with hydrogen chemisorption, nitrogen adsorption, X-ray photoelectron spectroscopy and electron microscopy. Studies showed that the most active sample, synthesized by microemulsion method, is characterized by highest surface area and highest concentration of surface active metal as compared with to other samples. The sample surface consists of 57-61 at. % Cu+2, Zn+2, Al+3 in form of oxides and 1.5-3.0 at. % Zn+2, Al+3 in form of aluminates. The sample synthesized by mechanical grinding of oxides showed the lowest activity in hydrogen sulfide sorption that explains by higher concentration of aluminates in the active face. The results of Zn/Cu sorption activity showed well correlation of hydrogen sulfide sorption capacity with sample surface area and surface concentration of active metal.Forcitation:Doluda V.Yu., Sulman M.G., Matveeva V.G., Lakina N.V., Sulman E.M. Zn/Cu sorbent synthesis for Syn-gas purification from hydrogen sulfide. Izv. Vyssh. Uchebn. Zaved. Khim. Khim. Tekhnol. 2017. V. 60. N 3. P. 61-66.

Study on Wet-Grinding Preparation of Micro-Nano β-SiC

In this research, the effects of main parameters such as speed of agitator, concentration and redium change ratio on the grinding effect were studied by the method of wet-grinding. The powder was characterized and analyzed by means of particle size analysis and scanning electron microscope. The results show that the mechanical grinding method can effectively prepare micro-nanosilicon carbide powder with particle size of about 130nm, the optimum parameter is the rotational speed 1000r/min, the concentration is 30%, the medium change ratio is 75%.

Influence of Surface Roughness and Agitation on the Morphology of Magnetite Films Electrodeposited on Carbon Steel Substrates

In this work, we investigated the effects of surface roughness and agitation on the morphology of magnetite films electrodeposited from alkaline Fe(III)-triethanolamine (TEA) solutions on carbon steel substrates. The surface roughness of the carbon steel substrates was maintained in the range of 1.64–0.06 μm by using mechanical grinding and polishing methods. The agitation speed was set at 0 and 900 rpm during the electrodeposition process. The particle size and surface roughness value of the magnetite films gradually decreased with decreasing substrate roughness. However, the influence of the substrate roughness on the thickness of the magnetite film was negligible. The morphology of the magnetite film fabricated at 900 rpm appeared to be highly faceted compared to that of the magnetite film produced at 0 rpm. The thickness and surface roughness of the magnetite film significantly increased with the agitation speed, which also significantly affected the electrodeposition efficiency. The effects of substrate surface roughness and agitation on the morphology of magnetite films electrodeposited on carbon steel substrates were also discussed. The obtained results provide critical information for the simulation of magnetite deposits on carbon steel pipes in the secondary systems of nuclear power plants.

Fabrication of C3N4 ultrathin flakes by mechanical grind method with enhanced photocatalysis and photoelectrochemical performance

In this paper, we prepared a large-sized multilayer C3N4 ultrathin flake photocatalyst with an approximately 90% yield rate by a facile wet mechanical grinding method.

Preparation of Nano‐Sized Copper β‐Resorcylate (β‐Cu) and its Excellent Catalytic Activity for the Thermal Decomposition of Ammonium Perchlorate

AbstractCopper β‐resorcylate (cupric 2,4‐dihydroxy‐benzoate, β‐Cu) nanoparticles were prepared at a large‐scale via a facile wet mechanical grinding method and vacuum freeze‐drying process. The as‐prepared β‐Cu nanoparticles were characterized by powder X‐ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and Fourier‐transform infrared spectroscopy (FT‐IR). The results revealed that the nano‐sized β‐Cu is of semi‐spherical shape and of homogeneous distribution, with a fairly uniform size of 100 nm. The formation mechanism of β‐Cu nanoparticles in the whole process was discussed in detail. Furthermore, the catalytic properties of as‐obtained β‐Cu were investigated. The TG/DSC study showed that nano‐sized β‐Cu could be a promising additive for accelerating the thermal decomposition of ammonium perchlorate (AP).

Influence of surface roughness on the corrosion behavior of Alloy 690TT in PWR primary water

The purpose of this work is to investigate the effect of surface roughness on the corrosion behavior of Alloy 690TT steam generator tube material in simulated primary water at 330°C. The surface roughness was controlled in the range of 710–25nm by mechanical grinding and polishing method. Surface hardness gradually decreased with a decrease in the roughness value. Polyhedral oxide particles were formed on the ground surfaces, whereas the mixed oxides of a polyhedral and strip-like type were observed on the polished surface. The corrosion rate decreased by about 64% as the roughness values decreased from 710 to 150nm. However, no further changes were observed in the range of 150–25nm.

An efficient DNA extraction method from bone and tooth samples by complete demineralization followed by the use of silica-based columns

A highly efficient strategy for recovery of genomic DNA from bone and tooth samples is presented by complete demineralization of the bone pieces or intact tooth with high concentration of EDTA followed by spin column treatment without the need of mechanical grinding or cryogenic method for pulverizing the samples. The DNA yield was between 8 and 12 ng/?l from approximately 1 ?2 g of the starting material. Completed DNA profiles were obtained from of all the bones (52) and tooth (270) samples received from the unidentified victims from a recent building collapse, the Rana Plaza disaster in Dhaka, Bangladesh. DOI: http://dx.doi.org/10.3329/dujbs.v23i2.20089 Dhaka Univ. J. Biol. Sci. 23(2): 101-107, 2014

Experimental Study on the Preparation Process of Binary Carbonate Salts

Ten kinds of binary carbonate salts with different ratio were respectively prepared by two kinds of preparation processes and the research on thermo-physical properties, thermal stability and component analysis was worked respectively by Differential Scanning Calorimetry instrument and XRD analytical instrument. The results showed: There was little difference on melting point and decomposition point between the samples prepared by two kinds of methods and well matched with that of reference phase diagram; For the preparation of mixed carbonate, static melting method was superior to the simple mechanical grinding method through TG and DSC curves of multiple cycles; There was no new material produced in both two kinds of preparation processes from the XRD composition analysis.