scholarly journals Encapsulated Urea-Kaolinite Nanocomposite for Controlled Release Fertilizer Formulations

2015 ◽  
Vol 2015 ◽  
pp. 1-17 ◽  
Author(s):  
Siafu Ibahati Sempeho ◽  
Hee Taik Kim ◽  
Egid Mubofu ◽  
Alexander Pogrebnoi ◽  
Godlisten Shao ◽  
...  
Keyword(s):  
Particle Size ◽  
Controlled Release ◽  
Crystal Lattice ◽  
Gum Arabic ◽  
Sem Analysis ◽  
Particle Sizes ◽  
Major Phase ◽  
Controlled Release Fertilizer ◽  
X Ray ◽  
And Diffusion

Urea controlled release fertilizer (CRF) was prepared via kaolinite intercalation followed by gum arabic encapsulation in an attempt to reduce its severe losses associated with dissolution, hydrolysis, and diffusion. Following the beneficiation, the nonkaolinite fraction decreased from 39.58% to 0.36% whereas the kaolinite fraction increased from 60.42% to 99.64%. The X-ray diffractions showed that kaolinite was a major phase with FCC Bravais crystal lattice with particle sizes ranging between 14.6 nm and 92.5 nm. The particle size varied with intercalation ratios with methanol intercalated kaolinite > DMSO-kaolinite > urea-kaolinite (KPDMU). Following intercalation, SEM analysis revealed a change of order from thick compact overlapping euhedral pseudohexagonal platelets to irregular booklets which later transformed to vermiform morphology and dispersed euhedral pseudohexagonal platelets. Besides, dispersed euhedral pseudohexagonal platelets were seen to coexist with blocky-vermicular booklets. In addition, a unique brain-form agglomeration which transformed into roundish particles mart was observed after encapsulation. The nanocomposites decomposed between 48 and 600°C. Release profiles showed that 100% of urea was released in 97 hours from KPDMU while 87% was released in 150 hours from the encapsulated nanocomposite. The findings established that it is possible to use Pugu kaolinite and gum arabic biopolymer to prepare urea CRF formulations.

Use of Ceramic Waste for the Manufacture of Sintered Parts

2020 ◽  
Vol 1012 ◽  
pp. 233-238
Author(s):  
Vanessa Moura de Souza ◽  
Vinícius Martins ◽  
Rejane Maria Candiota Tubino
Keyword(s):  
Particle Size ◽  
Selection Process ◽  
Compaction Pressure ◽  
Raw Material ◽  
Powder Technology ◽  
Particle Sizes ◽  
Compression Pressure ◽  
X Ray ◽  
Ceramic Waste ◽  
Quality Process

This paper evaluated the use of the pitcher, a ceramic waste obtained through the quality process of a sanitary ware industry, in the development of a material for usage in the manufacture of sintered parts. The pitcher was obtained through powder technology and is composed, according to the chemical analysis obtained by X-ray fluorescence spectrometry, of clayey minerals (clay and kaolin), quartz, and feldspar, which may include ceramic rocks such as granite, pegmatite and phyllite; that is, it has proved to be a potential raw material due to the minerals that can still be reused. The pitcher passed through a granulometry-based selection process, sieving about 20kg using the following sieve sequence: 18 MESH, 25 MESH, 30 MESH, 120 MESH and 400 MESH; with around 70% of the residue being retained in the sieves of 120 and 400 MESH, which were selected to be used in the evaluation. The samples were compacted in a manual press with different pressures, between 300 and 1000 kgf, and after were sintered at a temperature of 1100oC in a resistive furnace. To characterize the material, the apparent and green density, as well as the compressibility curve, were determined to identify the best compression pressure. The microstructure of the test specimen and the pitcher homogeneity were evaluated using Scanning Electron Microscopy (SEM). Both particle sizes presented the typical compressibility curve, in which the density increases with increasing compaction pressure, while the curve slope decreases with increasing pressure. The density increase with the increasing compaction pressure indicates a good densification for the temperatures, independent of the sample granulometry. The sintering porosity decreased proportionally to the particle size in the sintered samples. The analysis showed that the particle size of 400 MESH sintered at 1100oC obtained more porous surfaces, thus indicating a promising future for the manufacture of parts using powder technology, especially for the development of filters.

scholarly journals Effects of Gum Arabic-Coated Magnetite Nanoparticles on the Removal of Pb Ions from Aqueous Solutions

2021 ◽  
pp. 889-896
Author(s):  
Hanan J. Mustafa ◽  
Tagreed M. Al-Saadi
Keyword(s):  
Aqueous Solutions ◽  
Crystallite Size ◽  
Magnetite Nanoparticles ◽  
Gum Arabic ◽  
Xrd Analysis ◽  
Sem Analysis ◽  
Absorption Bands ◽  
X Ray ◽  
Ft Ir ◽  
Pb Ions

To study the removal of lead (Pb) ions from aqueous solutions, novel magnetite nanoparticles (NPs) of Ni0.31Mg0.15Ag0.04Fe2.5O4 were synthesized by coprecipitation synthesis using metal sulfates, and then coated with Gum Arabic (GA). The prepared NPs were analyzed using various spectroscopic and analytical methods, such as X-Ray diffraction analysis (XRD), Field Emission Scanning Electron Microscopy (FE-SEM), Energy Dispersive X-ray spectroscopy (EDX), Fourier Transform Infra-Red spectroscopy (FT-IR), and Atomic Absorption Spectrophotometer (AAS). By using XRD analysis, the cubic inverse spinel structure of the prepared NPs was proven, showing average values of crystallite size, lattice constant, and density of 28.57nm, 8.32582Å, and 5.2890 g/cm3, respectively. FE-SEM analysis revealed the sphere-like shape of the nanoparticles with a measured crystallite size of 25.93nm. The existence of constituent elements was evidenced by EDX. FT-IR test proved the success of the coating process of magnetite NPs by the presence of the main characteristic absorption bands of GA in the FT-IR spectrum of GA-magnetite NPs. The adsorption of Pb ions by GA- magnetite NPs was shown by AAS analysis, where the concentration of Pb ions decreased from 25ppm to 6.6ppm, reaching 1.1ppm at the time of 25min. The porosity of the NPs and the carboxyl groups in GA played an important role in the process.

scholarly journals Theoretical and Experimental Evaluation of Particle size Effect of Iron , Cobalt ,and Nickel Powders Suspended in Al Dura oil on XRF Intensities

2007 ◽  
Vol 4 (3) ◽  
pp. 475-481
Author(s):  
Baghdad Science Journal
Keyword(s):  
Particle Size ◽  
Particle Size Distribution ◽  
Laser System ◽  
Particle Size Effect ◽  
Particle Sizes ◽  
Iron Cobalt ◽  
X Ray ◽  
Nickel Powders ◽  
Good Agreement ◽  
Cobalt And Nickel

Iron , Cobalt , and Nickel powders with different particle sizes were subjected to sieving and He-Ne laser system to determine the particle size . 1wt% from each powders was blended carefully with 99wt% from Iraqi oil . Microscopic examination were carried for all samples to reveal the particle size distribution . A Siemens type SRS sequential wavelength dispersive(WDS) X-ray spectrometer was used to analyze all samples , and the XRF intensity were determined experimentally and theoretically for all suspended samples , Good agreement between theoretical and experimental results were found .

scholarly journals Effects of Size and Dispersity of Microcrystalline Celluloses on Size, Structure and Stability of Nanocrystalline Celluloses Extracted by Acid Hydrolysis

Nano LIFE ◽  
2014 ◽  
Vol 04 (04) ◽  
pp. 1441014 ◽  
Author(s):  
Qi Liu ◽  
Weiping Hao ◽  
Yongguang Yang ◽  
Aurore Richel ◽  
Canbin Ouyang ◽  
...  
Keyword(s):  
Particle Size ◽  
Acid Hydrolysis ◽  
Size Structure ◽  
Particle Sizes ◽  
X Ray Diffraction ◽  
X Ray ◽  
Force Microscopy ◽  
Atomic Force ◽  
Transmission Electron ◽  
Sonication Treatment

Nanocrystalline celluloses (NCCs) were separated from four commercial microcrystalline celluloses (MCCs) by an acid hydrolysis–sonication treatment. Transmission electron microscopy (TEM), atomic force microscopy (AFM), Fourier transform infrared (FTIR) spectrum, X-ray diffraction (XRD) and thermogravimetric analysis (TGA) were conducted to investigate the NCCs. MCCs with different morphologies and particle sizes showed different aggregation degrees. The aggregation of MCCs followed the order MCC1 > MCC3 > MCC2 > MCC4, which is the same order of the heights of the resulting NCCs. The best uniformity and thermal stability were characterized for NCC3, which was produced by MCC3 with smallest original particle size and good dispersity among the four MCCs. This result suggests that both the original particle size and dispersity of MCCs had significant effects on separated NCCs.

Overvoltage and diffusion through iron and palladium

1959 ◽  
Vol 253 (1272) ◽  
pp. 6-15 ◽  
Keyword(s):  
Crystal Lattice ◽  
Single Crystals ◽  
Molecular Hydrogen ◽  
X Ray Diffraction ◽  
Palladium Hydride ◽  
X Ray ◽  
Crystallographic Planes ◽  
And Diffusion ◽  
Diffusion Of Hydrogen ◽  
Crystal Boundaries

Observations are recorded on X-ray spectra diffracted from cathodes of iron and palladium during actual discharge and diffusion of hydrogen. For iron, no expansion of the crystal lattice greater than 0.0002 Å could be observed during such diffusion, and the broadening observed of X-ray diffraction spectra indicated no preferred crystallographic planes for the evolution of molecular hydrogen. Blisters were formed across the faces of single crystals of iron, when made a cathode, indicating that diffusion of hydrogen occurs through the crystal grains rather than along crystal boundaries. For palladium, an expansion was observed during actual electrolysis to an extent of 0.0170 + 0.0002 Å. On ceasing electrolysis, there was reversion to a less-expanded lattice of palladium hydride. Broadening of the reflexions observed during electrolysis indicated no preferred planes for evolution of hydrogen. The significance of these findings is discussed for mechanisms of overvoltage and of diffusion of hydrogen through metals.

Effect of Ti Particle Size on Reaction Synthesis of Ti Aluminide

2012 ◽  
Vol 710 ◽  
pp. 314-319 ◽  
Author(s):  
Rohit Kumar Gupta ◽  
Bhanu Pant ◽  
Vijaya Agarwala ◽  
Parameshwar Prasad Sinha
Keyword(s):  
Particle Size ◽  
High Temperature ◽  
Titanium Aluminide ◽  
Reaction Synthesis ◽  
Particle Sizes ◽  
Minor Phase ◽  
Chemical Homogeneity ◽  
Major Phase ◽  
Ti Powder

Titanium aluminide intermetallic was made through reaction synthesis (RS) process using elemental powders. Pressure assisted synthesis was carried out at high temperature under vacuum. Ti powder with two different particle sizes (200μm and 30μm average) were used in RS. Synthesized blocks were homogenized and characterized for chemical homogeneity, density, phase formation and microstructure evolution. Products near to theoretical density have been obtained with uniform chemistry after homogenization. Al3Ti as a major phase along with TiAl as minor phase was confirmed after RS and TiAl along with Ti3Al was observed after homogenization. Homogenization cycle was found to be different for the alloys made through different Ti particle sizes. Significant role of Ti particle size has been observed in this pressure assisted RS process.

scholarly journals Parametric Study of Matisaa Gray Rock as a Potential Clinker Material

2020 ◽  
pp. 22-29
Author(s):  
Mwendwa Geoffrey ◽  
Motochi Isaac ◽  
Otieno Fredrick
Keyword(s):  
Particle Size ◽  
Size Composition ◽  
Particle Size Analysis ◽  
Raw Material ◽  
Size Analysis ◽  
Particle Sizes ◽  
X Ray ◽  
Saturation Factor ◽  
Clinker Production

This study aimed at evaluating Matisaa gray rock (MGR) for clinker production. MGR is naturally abundant in Matisaa, a rural area in Mwingi West District, Kitui county, Kenya. It is locally used as a gabion filler and other concrete structures with desirable physico-mechanical properties. This research employed a controlled experimental design to determine the clinker qualification of MGR. This was based on particle size analysis and raw meal moduli. The standard sieve tests and a Blaine meter were used in the determination of particle size while the raw meal moduli were determined from the respective cement oxides in MGR, which were determined using wavelength dispersive X-ray fluorescence (WDXRF) spectrometer. It was observed that 69.65% of the particle size composition of MGR was less than 90 . Out of this composition, 71.60% of the particle sizes were less than 45 , contributing to a specific surface area of 292.5 . The hydraulic modulus (2.05 – 2.61) and lime saturation factor (0.87 – 0.98) are quite desirable though the silica and alumina ratios are higher than the standard range due to the low proportions of  and  content. The sulfatisation modulus is also undesirable due to the high content of . Thus, without beneficiation, Matisaa gray rock would lead to the production of low-quality clinker. However, the general parametric comparison of Matisaa gray rock with Konza shows that it has the potential for utilization as a clinker raw material.

Conquer by cryo-EM without physically dividing

2021 ◽  
Author(s):  
Gabriel C. Lander ◽  
Robert M. Glaeser
Keyword(s):  
Particle Size ◽  
High Resolution ◽  
Single Particle ◽  
Region Of Interest ◽  
Divide And Conquer ◽  
Particle Sizes ◽  
X Ray ◽  
X Ray Crystallography ◽  
Substantial Progress ◽  
Made In

This mini-review provides an update regarding the substantial progress that has been made in using single-particle cryo-EM to obtain high-resolution structures for proteins and other macromolecules whose particle sizes are smaller than 100 kDa. We point out that establishing the limits of what can be accomplished, both in terms of particle size and attainable resolution, serves as a guide for what might be expected when attempting to improve the resolution of small flexible portions of a larger structure using focused refinement approaches. These approaches, which involve computationally ignoring all but a specific, targeted region of interest on the macromolecules, is known as ‘masking and refining,' and it thus is the computational equivalent of the ‘divide and conquer' approach that has been used so successfully in X-ray crystallography. The benefit of masked refinement, however, is that one is able to determine structures in their native architectural context, without physically separating them from the biological connections that they require for their function. This mini-review also compares where experimental achievements currently stand relative to various theoretical estimates for the smallest particle size that can be successfully reconstructed to high resolution. Since it is clear that a substantial gap still remains between the two, we briefly recap the areas in which further improvement seems possible, both in equipment and in methods.

Sintering Behaviors of Pt Nanopowders with Different Particle Sizes: A Real-Time Synchrotron X-ray Scattering Study

2021 ◽  
Vol 16 (5) ◽  
pp. 849-853
Author(s):  
Jang-Hyeong Lee ◽  
Tae-Sik Cho
Keyword(s):  
Particle Size ◽  
Solid State ◽  
Grain Boundary ◽  
Grain Growth ◽  
Boundary Diffusion ◽  
Domain Size ◽  
Particle Sizes ◽  
X Ray ◽  
X Ray Scattering ◽  
Solid State Sintering

We have studied the solid state sintering behaviors of platinum (Pt) nanopowders with different particle sizes using real-time synchrotron X-ray scattering in air. Pt powders with large particle size of 101 nm at room temperature (RT) showed a defect-free crystal domain size of 10 nm. Most of these powders exhibited multiple grains inside the particle. Solid state sintering of the powders mainly occurred through surface diffusion of Pt atoms near 145 °C, grain boundary diffusion from 150 to 400 °C, and then grain growth above 550 °C. Meanwhile, Pt nanopowders with small particle size of 18 nm at RT showed a crystal domain size of 8 nm. Most of these powders exhibited a single grain inside the particle. Solid state sintering of the nanopowders mainly occurred through surface diffusion of Pt atoms near 151 °C and then grain growth above 400 °C. Grain boundary diffusion does not happen because grain boundary hardly exists.

Investigation of Mg2Si formation from Si and Mg by using spark plasma sintering synthesis

2015 ◽  
Vol 1735 ◽  
Author(s):  
Kota Sunohara ◽  
Koya Arai ◽  
Tomoyuki Nakamura ◽  
Kenjiro Fujimoto ◽  
Yuki Yamaguchi ◽  
...  
Keyword(s):  
Particle Size ◽  
Spark Plasma Sintering ◽  
Inert Gas ◽  
Particle Sizes ◽  
X Ray Diffraction ◽  
X Ray ◽  
Plasma Sintering ◽  
Spark Plasma

AbstractIn this study, we fabricated Mg2Si from metal Mg and Si with different particle sizes (425 - 300, 300 - 180, and 75 μm or less) using spark plasma sintering (SPS) equipment. Additionally, the Mg2Si formation was investigated. A sieved Si powder was mixed with metal Mg powder in an inert gas (Ar) atmosphere. The mixture was placed in a graphite die while still in an Ar atmosphere and subjected to SPS at 923 K and 1113 K. The obtained sintering bodies were Mg2Si particles with a size of about 5 μm. Then, the sintered bodies were evaluated by X-ray diffraction (XRD). As a result, it was confirmed that generation of Mg2Si increased with decreasing Si particle size.

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