Microencapsulated Alachlor and Its Behavior on Wheat (Triticum aestivum) Straw

Weed Science ◽  
1989 ◽  
Vol 37 (5) ◽  
pp. 719-723 ◽  
Author(s):  
Brent B. Petersen ◽  
Patrick J. Shea

Scanning electron microscopy (SEM) was used to study alachlor microcapsule morphology and the effects of straw age and moisture on herbicide release. Microcapsule diameter in the formulation ranged from 2 to 15 μm. The polyurea encapsulating material was stable in water over time. Diffusion was suggested as the primary mode of alachlor release, with diffusion rate controlled by herbicide and salt concentration gradients between the microcapsule and the surrounding aqueous solution. Alachlor release was promoted by drying the microcapsules before addition to water. Microcapsule morphology was unchanged 48 h after application to dry straw, and microcapsules did not appear to adhere to the straw surface. Microcapsules applied to overwintered wet straw were shriveled at 48 h after treatment, indicating herbicide loss. Capsule walls were broken and appeared brittle after application to fresh wet straw. Organic constituents of the fresh straw cuticle may affect capsule wall integrity.

2019 ◽  
Vol 38 (3) ◽  
pp. 682-702 ◽  
Author(s):  
Zepeng Sun ◽  
Yue Ni ◽  
Yongli Wang ◽  
Zhifu Wei ◽  
Baoxiang Wu ◽  
...  

The chemical and physical capabilities of shale can be altered by the interactions between fracturing fluid and shale formation, affecting the long-term reservoir productivity. To obtain information regarding how fracturing fluids with different components impact the pore structure, porosity and mineral compositions of shale reservoir rocks over time, two different types of commercial fracturing fluids (slick water and crosslinked gel) were used to react with the shales from Longmaxi Formation of Lower Silurian in the Sichuan Basin of South China. Experiments were conducted with various time intervals (1, 4 and 10 days) in a reactor at 50 MPa and 100°C, and then analytical methods including X-ray diffraction, low pressure nitrogen adsorption, field emission scanning electron microscopy and porosity measurement were used to examine the changes of mineralogical compositions, pore structure and porosity. The results demonstrated that the mineral compositions of shale samples were significantly changed after treatment with two different fracturing fluids for 4 days. The analysis of field emission scanning electron microscopy revealed that the carbonate minerals were dissolved and developed many dissolution pores after slick water treatment, while the crosslinked gel mainly caused the precipitation of carbonate minerals. After exposure to different fracturing fluids, the total pore volume and specific surface area decreased over time. Moreover, the fractal dimensions (D1 and D2) of shale showed an apparent decrease trend after treatment with two different fracturing fluids, indicating that the pore surface and structure become smooth and regular. The porosity of shale significantly decreased by 15.9% and 17.8%, respectively, after 10 days of slick water and crosslinked gel treatment. These results indicated that the injection of the two different types of fracturing fluids may negatively impact the shale gas production through reducing the nanopore structure and porosity of shale reservoir rocks.


2015 ◽  
Vol 2015 ◽  
pp. 1-6 ◽  
Author(s):  
Mingjie Ma ◽  
Guanyu Wang ◽  
Zhengpeng Yang ◽  
Shanxiu Huang ◽  
Weijie Guo ◽  
...  

Solid waste red mud was modified by HCl leaching. The structure property and composition of modified red mud were investigated by X-ray diffraction (XRD), X-ray fluorescence spectroscopy (XRF), scanning electron microscopy (SEM), and Brunauer-Emmett-Teller (BET). Under UV irradiation, methyl orange (MO) aqueous solution was photodegraded by modified red mud. The obtained results showed that the specific surface area of modified red mud was 317.14 m2/g, which was about 40 times higher than that of the normal red mud. After UV irradiation for 50 min, the removal percentage of MO reached 94.2%. The study provided a novel way for the application of red mud to the photocatalytic degradation of organic wastes.


Microscopy ◽  
2016 ◽  
Vol 65 (suppl 1) ◽  
pp. i17.1-i17
Author(s):  
Toshiko Yamazawa ◽  
Naotoshi Nakamura ◽  
Yoshinori Mikami ◽  
Hiroshi Sekiya ◽  
Mari Sato ◽  
...  

1988 ◽  
Vol 66 (5) ◽  
pp. 829-838 ◽  
Author(s):  
M. J. Hodson ◽  
A. G. Sangster

Silica deposition in the lower glume, lemma, and palea of wheat (Triticum aestivum L. cv. Highbury) was investigated using scanning electron microscopy and light microscopy. Silica was present in the outer walls of all the epidermal cells including prickles and papillae of the glume and lemma awns. The glume and the lemma were similar in epidermal silica deposition pattern, both having numerous silicified short trichomes and papillae on inner and outer surfaces. Epidermal long cells and short cells were also silicified. Macrohairs were restricted to isolated areas in these bracts, particularly on the inner surfaces just beneath the awns. The palea was a thin membranous structure differing markedly from the other two bracts. Most of the palea is pressed between the caryopsis and the next floret, and both surfaces are almost devoid of trichomes in these areas. However, at the apex and margins of the palea, macrohairs and papillae were abundant. The results are discussed with respect to possible taxonomic, anatomical, medical, and archaeological implications.


2014 ◽  
Vol 614 ◽  
pp. 140-143 ◽  
Author(s):  
Florin Miculescu ◽  
Lucian Toma Ciocan ◽  
Daniela Meghea ◽  
Marian Miculescu

Sintered ceramics and ceramic glasses are frequently used as biomaterials for dental restorations, usually for inlays, onlays, veneers, crowns or bridges. In this study we analyzed several types of ceramic-ceramic type prosthetic restorations in order to assess the types of defects that can lead to their failure. The research aim is to morphologically identify by scanning electron microscopy the main types of defects that lead to failure over time of ceramic-ceramic prostheses type. The type of failure registered were fracture of plating material (feldspatic porcelain) and fracture of entire structure (zirconia and feldspatic porcelain).


2015 ◽  
Vol 46 (5) ◽  
pp. 1872-1882 ◽  
Author(s):  
NASSIRHADJY MEMTILY ◽  
TOMOKO OKADA ◽  
TATSUHIKO EBIHARA ◽  
MARI SATO ◽  
ATSUSHI KURABAYASHI ◽  
...  

2007 ◽  
Vol 280-283 ◽  
pp. 529-532
Author(s):  
Yu Jia ◽  
Yuji Hotta ◽  
Kimiyasu Sato ◽  
Koji Watari ◽  
Lennart Bergström

Monodispersed ZrO2 (includes 8mol % Y2O3) precursor nanoparticles, which were well dispersed in aqueous solution, were successfully synthesized. The as-synthesized ZrO2 precursor nanoparticles were homogenously coated on the surface of polystyrene particles. Multilayer coating process was successfully implemented by using polyacrylic acid (PAA) to modify the surface charges of the coated particles, which was characterized by zeta-potential, particles size distribution and scanning electron microscopy (SEM).


Respuestas ◽  
2021 ◽  
Vol 25 (2) ◽  
pp. 117-124
Author(s):  
Henry Mauricio-Mateus ◽  
José Barba-Ortega ◽  
Miryam Rincón-Joya

In this work, we studied the change in the electric current and the length of the nanotubes depending on the area and the exposure time in the anodizing process. Over time the anodizing area was changed with a rate of 0.5 cm2 to 2.5 cm2 using a total anodizing time of 60 min, using a chemical solution (2ml  /3 ml /0.30g ) and maintaining a constant anodizing voltage equal to 20 V. The behavior in the nanostructures was recorded by the evolution of the current density as a function of the anodizing time. The morphology of the nanostructures was analyzed by means of scanning electron microscopy (SEM). With the use of the Imagej program. The size, length and diameter of the titanium nanostructures are obtained. The sample that presented the best behavior was that of an anodizing area of ​​1.5 cm2  and an anodizing time of 36 min. This presents a surface where open nanotubes are observed in the upper part with a vertical length of 0.23 μm and a pattern thereof organized in a circular arrangement with a diameter of 0.035 μm. It was observed that increasing the area under these anodizing conditions decreased the length of the nanotubes. The mobility of the loads was always greater with the area of ​​exposure, which is observed in the increase of the current


2021 ◽  
Vol 43 (1) ◽  
pp. 14-14
Author(s):  
Fazal Akbar Jan Fazal Akbar Jan ◽  
Muhammad Aamir Muhammad Aamir ◽  
Naimat Ullah and Husaain Gulab Naimat Ullah and Husaain Gulab

The synthesized oxide (SnO2) nanoparticles by sol-gel method were characterized using UV-Visible spectroscopy (UV-Vis), Fourier Transform Infrared spectroscopy (FTIR), X-rays diffraction(XRD) and Scanning electron microscopy(SEM). Using X-rays diffraction analysis different parameter were calculated such as crystallite size, d-spacing, dislocation density, number of unit cell, cell volume, morphological index, micro strain and instrumental broadening. The average particle size was 28.396 nm. Scanning electron microscopy revealed that SnO2 nanopartcles are uniformly distributed. Optical properties such as band gap (energy gap = 3.6 eV) was calculated from UV-Visible spectroscopy. The characterized particles were used as photocatalyst for the degradation of Eosin dye in aqueous solution under UV light. The effect of different parameters i.e irradiation time, initial dye concentration, pH of the medium and catalyst weight on percent degradation was also studied. Mmaximum dye degradation was found at 220 minutes time interval that was 92 % using 10 ppm solution. At pH 5 the degradation of dye was found to be 94%. The catalyst dose of 0.06 g was found to be the optimum weight for the best photo catalytic degradation of Eosin Y.


2016 ◽  
Vol 61 (2) ◽  
pp. 1221-1227
Author(s):  
T. Ratajski ◽  
I. Kalemba-Rec ◽  
B. Dubiel

Abstract The SiO2 and Ni/SiO2 coatings were electrophoretically deposited on X2CrNiMo17-12-2 steel using ethanol-based suspensions of the SiO2 and Ni powders. The influence of the zeta potential and concentration of the suspensions, the applied voltage and deposition time on the quality of the coatings was studied. Microstructure of the plan-view and cross sections of the coatings was investigated using scanning electron microscopy. The plan-view images revealed the uniform microstructure of the coatings with sporadically observed cracks, pores as well SiO2 and Ni agglomerates. On the cross-sections, the Cr2O3 layer, resulted from oxidation of the substrate during sintering of the coatings was observed. The polarization tests have shown that SiO2 and Ni/SiO2 coatings improve the corrosion resistance of the X2CrNiMo17-12-2 steel in 3.5% NaCl aqueous solution.


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