scholarly journals STUDY OF SYNTHESIS FEATURES OF NANOCRYSTALLINE ZINC FERRITE

2018 ◽  
Vol 59 (1) ◽  
pp. 39
Author(s):  
N.P. Shabelskaya ◽  
S.I. Sulima ◽  
E.V. Sulima ◽  
A.I. Vlasenko
Keyword(s):  
Zinc Ferrite ◽  
Developed Surface ◽  
Scherrer Equation ◽  
Average Size

In work the process of formation of nanocrystal zinc ferrite was studied. The samples obtained were characterized with XPS, BET and SEM. The received samples have the developed surface. The average size of crystallites determined by Debye-Scherrer equation was 3 nm.

Experimental Investigations of the Detonation Synthesis of Micron Al2O3 by the Precursor of Thermal Decomposition

2014 ◽  
Vol 609-610 ◽  
pp. 165-168
Author(s):  
R.Y. Li ◽  
H.L. Yang ◽  
H.H. Yan ◽  
X.H. Wang ◽  
X.J. Li
Keyword(s):  
Thermal Decomposition ◽  
Weight Loss ◽  
Aluminum Hydroxide ◽  
Crystal Size ◽  
Endothermic Peak ◽  
Experimental Investigations ◽  
Detonation Synthesis ◽  
Average Crystal Size ◽  
Scherrer Equation ◽  
Average Size

The Al2O3 is synthesized by detonation of mixed explosive, prepared by mixing RDX and aluminum hydroxide named as precursor of thermal decomposition. The production of detonation is analysed by XRD, TEM and DTA/TG. The curve of XRD indicates that the production are (α+γ)-Al2O3. The average crystal size of Al2O3 is 126nm calculated by the Scherrer equation. The photographs of TEM show that all granules of Al2O3 are spherical, and the average size of granule is 1000nm. The visible exothermic or endothermic peak does not appear on the curve of DTA from 50 to 1300 degree Centigrade. The curve of TG indicates that the production of detonation generates 12% weight loss from 50 to 1300 degree Centigrade.

Surface Structure of Nanometer-Sized Zinc Ferrite Particles by the Anomalous X-ray Scattering (AXS) Method

1992 ◽  
Vol 47 (10) ◽  
pp. 1023-1028 ◽  
Author(s):  
Eiichiro Matsubara ◽  
Kaneharu Okuda ◽  
Yoshio Waseda ◽  
Toshihiko Saito
Keyword(s):  
Zinc Ferrite ◽  
Fine Particles ◽  
Particle Model ◽  
X Ray Diffraction ◽  
Interference Function ◽  
X Ray ◽  
X Ray Scattering ◽  
Peak Broadening ◽  
Average Size ◽  
Ray Scattering

AbstractThe atomic structure of nanometer-sized zinc ferrite particles has been studied with the anomalous x-ray scattering (AXS) method as well as the ordinary x-ray diffraction. The analysis of the peak broadening indicated that little microstrain exists in these nanometer-sized particles, and the average size of the particles is estimated to be 4 nm. Since the ratio of atoms located on the surface increases extremely in such fine particles, the contribution of these surface atoms to the x-ray scattering intensity was evaluated. The interference function Qi (Q) for the surface atoms appears to be similar to that of the zinc-ferrite glass. The experimental intensity is successfully explained by using a simple particle model consisting of the about 0.2 nm thick surface layer having a glass-like structure and the internal atoms having the ferrite crystalline structure.

The Decomposition of Zinc Ferrite in Electric Arc Furnace Dust by Carbon

2015 ◽  
Vol 658 ◽  
pp. 156-160
Author(s):  
Sureerat Polsilapa ◽  
Panupong Intakuean ◽  
Aimamon Promboobpa
Keyword(s):  
Zinc Oxide ◽  
Zinc Ferrite ◽  
Fine Powder ◽  
Electric Arc Furnace ◽  
Electric Arc ◽  
Carbon Powder ◽  
Arc Furnace ◽  
Pure Zinc ◽  
Electric Arc Furnace Dust ◽  
Average Size

The objective of this research is to study the mechanism of the decomposition of zinc ferrite to obtain crude zinc oxide (ZnO) and iron oxide by using carbon (activated carbon) powder as the reducing agent. Zinc ferrite could be mostly found in electric arc furnace dust (EAFD). Carbon with a purity of 99.99 percent by weight was ground to be fine powder with an average size of 75 microns. Then the mixer between zinc ferrite with carbon powder and EAFD with carbon at the ratio of 1:1, 1:2 and 1:3 by mole was carried out. The samples were treated in the range of temperatures at 600, 700 and 800 °C in TGA. The treated samples were analyzed by XRD in order to identify the phase transformation of zinc ferrite. It was found that the quantity of zinc ferrite, both either pure zinc ferrite and the zinc ferrite in EAFD were decreased after treating by carbon when using treating time at 120 minutes with the temperatures of 600, 700 and 800 °C, and ratio of zinc ferrite with carbon powder at 1:3 by mole. Moreover about 70% of zinc ferrite was decomposed to be zinc oxide (ZnO) and iron oxides.

Grain Refinement in Titanium-Erbium Alloys

1974 ◽  
Vol 32 ◽  
pp. 522-523
Author(s):  
B. B. Rath ◽  
J. E. O'Neal ◽  
R. J. Lederich
Keyword(s):  
Electron Microscopy ◽  
Size Distribution ◽  
Grain Refinement ◽  
Grain Growth ◽  
Volume Fraction ◽  
Pure Titanium ◽  
Systematic Investigation ◽  
Second Phase ◽  
Titanium Matrix ◽  
Average Size

Addition of small amounts of erbium has a profound effect on recrystallization and grain growth in titanium. Erbium, because of its negligible solubility in titanium, precipitates in the titanium matrix as a finely dispersed second phase. The presence of this phase, depending on its average size, distribution, and volume fraction in titanium, strongly inhibits the migration of grain boundaries during recrystallization and grain growth, and thus produces ultimate grains of sub-micrometer dimensions. A systematic investigation has been conducted to study the isothermal grain growth in electrolytically pure titanium and titanium-erbium alloys (Er concentration ranging from 0-0.3 at.%) over the temperature range of 450 to 850°C by electron microscopy.

Identification by Electron Microdiffraction of Intermetallic Phases in a Duplex Stainless Steel

1990 ◽  
Vol 48 (2) ◽  
pp. 494-495
Author(s):  
A. Redjaïmia ◽  
J.P. Morniroli ◽  
G. Metauer ◽  
M. Gantois
Keyword(s):  
Stainless Steel ◽  
Duplex Stainless Steel ◽  
Convergent Beam Electron Diffraction ◽  
Intermetallic Phases ◽  
Small Particles ◽  
Parallel Beam ◽  
Diffraction Patterns ◽  
Average Size ◽  
Convergent Beam ◽  
Electron Microdiffraction

2D and especially 3D symmetry information required to determine the crystal structure of four intermetallic phases present as small particles (average size in the range 100-500nm) in a Fe.22Cr.5Ni.3Mo.0.03C duplex stainless steel is not present in most Convergent Beam Electron Diffraction (CBED) patterns. Nevertheless it is possible to deduce many crystal features and to identify unambiguously these four phases by means of microdiffraction patterns obtained with a nearly parallel beam focused on a very small area (50-100nm).From examinations of the whole pattern reduced (RS) and full (FS) symmetries the 7 crystal systems and the 11 Laue classes are distinguished without ambiguity (1). By considering the shifts and the periodicity differences between the ZOLZ and FOLZ reflection nets on specific Zone Axis Patterns (ZAP) which depend on the crystal system, the centering type of the cell and the glide planes are simultaneously identified (2). This identification is easily done by comparisons with the corresponding simulated diffraction patterns.

Magnesium-zinc ferrite with copper substitutions

1998 ◽  
Vol 08 (PR2) ◽  
pp. Pr2-405-Pr2-408
Author(s):  
E. Rezlescu ◽  
N. Rezlescu ◽  
P. D. Popa ◽  
M. L. Craus ◽  
L. Rezlescu
Keyword(s):  
Zinc Ferrite

Depletion of coating color components in the blade coating process circulation

TAPPI Journal ◽  
2011 ◽  
Vol 10 (9) ◽  
pp. 17-23 ◽  
Author(s):  
ANNE RUTANEN ◽  
MARTTI TOIVAKKA
Keyword(s):  
Fine Particles ◽  
Particle Density ◽  
Stable Process ◽  
Size Fraction ◽  
Color Stability ◽  
Strong Interactions ◽  
Coating Process ◽  
Size Segregation ◽  
Coating Color ◽  
Average Size

Coating color stability, as defined by changes in its solid particle fraction, is important for runnability, quality, and costs of a paper coating operation. This study sought to determine whether the size or density of particles is important in size segregation in a pigment coating process. We used a laboratory coater to study changes in coating color composition during coating operations. The results suggest that size segregation occurs for high and low density particles. Regardless of the particle density, the fine particle size fraction (<0.2 μm) was the most prone for depletion, causing an increase in the average size of the particles. Strong interactions between the fine particles and other components also were associated with a low depletion tendency of fine particles. A stable process and improved efficiency of fine particles and binders can be achieved by controlling the depletion of fine particles.

Trophic position scales positively with body size within but not among four species of rocky reef predators

2020 ◽  
Vol 640 ◽  
pp. 189-200 ◽  
Author(s):  
AM Olson ◽  
A Frid ◽  
JBQ dos Santos ◽  
F Juanes
Keyword(s):  
Body Size ◽  
Trophic Position ◽  
Stomach Contents ◽  
Rocky Reef ◽  
Morphometric Traits ◽  
Predator Species ◽  
Predatory Fishes ◽  
Average Size ◽  
Interspecific Comparisons ◽  
Large Predators

Intra- and interspecifically, larger-bodied predators generally occupy higher trophic positions (TPs). With widespread declines in large predators, there is a need to understand their size-based trophic roles to predict ecosystem-level responses. In British Columbia, Canada, we examined size-based trophic interactions between predatory fishes—3 rockfish species (genus Sebastes) and lingcod Ophiodon elongatus—and their prey, converting predator δ15N signatures to TP and analyzing stomach contents. Intraspecifically, TP scaled positively with predator length and gape width, but the rates of change varied by species. Interspecifically, TP did not scale positively with the observed mean sizes or known maximum sizes of species. Lingcod TP was lower than that of yelloweye and quillback rockfishes, which were 51 and 37%, respectively, smaller than lingcod. Yellowtail rockfish had the smallest average size, yet their mean TP did not differ significantly from that of lingcod. Neither species differences in some morphometric traits known to influence body size-TP relationships nor phylogenetic history explained these results. Most prey consumed were <20% of the predator’s size, which might partially explain the lack of a size-based trophic hierarchy among species. Currently, large size classes of rockfishes are being lost due to fisheries and perhaps climate-driven changes. Our findings on intraspecific size-TP relationships indicate that fishery removals of large individuals may diminish trophic structures. Interspecific comparisons of TP suggest that, along with size, species remain an important factor in understanding trophic dynamics. In addition, smaller-bodied predator species may have significant ecological roles to be considered in ecosystem-based fisheries management.

Activation of regeneration of red and white pulp of the spleen after the combined transplantation of HSC and MSCS in terms of exposure to ionizing radiation

2017 ◽  
pp. 22-27
Author(s):  
И.Ю. Маклакова ◽  
Д.Ю. Гребнев ◽  
А.П. Ястребов
Keyword(s):  
Stem Cells ◽  
Ionizing Radiation ◽  
Hematopoietic Stem Cells ◽  
Morphometric Parameters ◽  
Hematopoietic Stem ◽  
Lymphoid Follicles ◽  
Average Area ◽  
Direct Technique ◽  
Average Size ◽  
Red Pulp

Цель - изучение влияния сочетанной трансплантации мультипотентных мезенхимальных стромальных (ММСК) и гемопоэтических стволовых клеток (ГСК), выделенных из плаценты, на регенерацию белой и красной пульпы селезенки в физиологических условиях и в условиях воздействия ионизующего излучения. Методика. Эксперименты выполнены белых лабораторных беспородных мышах-самцах. Облучение животных проводилось на гамма-терапевтической установке типа АГАТ-С с радионуклидным источником Co-60 типа ГИК-8-4, поглощенная доза составила 4,0 Гр, мощность поглощенной дозы 20 сГр/мин. Животным опытной группы внутривенно вводились аллогенные ММСК и ГСК соответственно в дозе 6 млн клеток/кг и 330 тыс. клеток/кг, суспендированные в 0,2 мл 0,9% раствора NaCl. Выделение гемопоэтических стволовых клеток осуществлялось методом прямой иммуномагнитной сепарации. Проводили морфометрию лимфоидных фолликулов селезенки (средняя площадь, средняя площадь В-зоны, средняя площадь герминативного центра, средняя площадь T-зоны), а также определялось среднее расстояние между центрами фолликулов и средняя клеточность красной пульпы. Результаты. Показано, что после воздействия ионизирующего излучения на фоне сочетанной трансплантации ММСК и ГСК происходит увеличение размеров лимфоидного фолликула за счет площади B-зоны фолликула, площади герминативного центра фолликула, восстановление содержания лимфобластов, пролимфоцитов и лимфоцитов до значений нормы. На фоне трансплантации ММСК и ГСК в условиях лучевой нагрузки установлено увеличение плотности клеток в красной пульпе селезенки и, как следствие, увеличение расстояния между центрами лимфоидных фолликулов. Увеличение плотности клеток в красной пульпе происходит как за счет увеличения содержания эритроидных клеток, так и за счет увеличения гранулоцитов. Заключение. Проведенные исследования свидетельствуют об эффективности сочетанной трансплантации ММСК и ГСК в отношении основных морфометрических показателей селезенки после воздействия ионизирующего излучения. The purpose of this work was to study the effect of combined transplantation of multipotent mesenchymal stromal (MSCS) and hematopoietic stem cells (HSCs) isolated from the placenta, on the regeneration of white and red pulp of the spleen under physiological conditions and in conditions of exposure to ionizing radiation. Methods. The experiments were performed with laboratory mice-males. We studied the influence of ionizing radiation dose of 4.0 Gy. Animals of the experimental group were intravenously infused into MMSC and GSK respectively at a dose of 6 million cells/kg and 330 thousand cells/kg, suspended in 0.2 ml of 0.9% NaCl solution. The selection of hematopoietic stem cells was carried out using the direct technique of immune magnetic separation. Were studied the following morphometric parameters of the spleen: the average area of lymphoid follicles, the average area of zone of lymphoid follicles, average size of germinal center of lymphoid follicles, average size T-zones of lymphoid follicles, the average distance between the centers of the follicles, the average cellularity of the red pulp. Results. As a result, of research obtained that after exposure to ionizing radiation on the background of combined transplantation of HSC and MSCS there is an increase in size of lymphoid follicle at the expense of area B-zone of the follicle, the area germinative center of the follicle, restoring the content of lymphoblasts and lymphoblasts and lymphocytes to normal values. On the background of transplantation MMSC and GSK in terms of radiation exposure changes and the red pulp of the spleen. The increase in the density of cells in the red pulp of the spleen and, as a consequence, of the increase of the distance between the centers of lymphoid follicles. The increase in the density of cells in the red pulp occurs due to the increase in the content of erythroid cells and by increasing granulocytes. Key words: ionizing radiation, multipotent mesenchymal stromal cells, hematopoietic stem cells, spleen, regeneration. Conclusion. Studies have shown the effectiveness of combined transplantation MSC and GSK in respect of the main morphometric parameters of the spleen after exposure to ionizing radiation.

EARLY RESULTS OF INGUINAL HERNIA REPAIR BY THE “MESH PLUG” TECHNIQUE

2012 ◽  
pp. 43-51
Author(s):  
Doan Van Phu Nguyen ◽  
Loc Le ◽  
Van Lieu Nguyen
Keyword(s):  
Inguinal Hernia ◽  
Postoperative Pain ◽  
Operating Time ◽  
Life Assessment ◽  
Medium Size ◽  
Mesh Plug ◽  
Postoperative Rehabilitation ◽  
Early Return ◽  
Early Results ◽  
Average Size

Background: In 1989, Lichtenstein I. L., Shulman A. G., Amid P. K., and Montlor M. M. presented an idea of using Mesh Plug to repair the defect inguinal canal. The new technique quickly became accepted by surgeons all over the world for several reasons: faster overall rehabilitation, less postoperative pain, less complication, shorter stay in the hospital and early return to normal activities and work. Materials and method: From Dec 2011 to July 2012, 42 patients with inguinal hernia were surgically treated with 48 Mesh Plugs applied at the Surgery Unit of Hue University of Medicine and Pharmacy. Result: The patients’ average age was 49.12±21.17. There were 25 patients over 40 years old, accounting for 59,5%, and 39 of the group were males, accounting for 92.8%. 10 cases were direct hernia, accounting for 20.8%, and 38 cases were indirect hernia accounting for 79.2%. Based on Nyhus’s classification, there were 33 cases of IIIA and IIIB (68.8%). Based on the position of protrusion, there were 30 cases of right inguinal hernia (62.5%), 18 cases of left inguinal hernia (37.5%), and 6 cases of hernia on both sides. The average size of the deep ring is 2.16±1.64cm. 24 cases used Mesh Plug of medium size (54.5%). The mean operating time was 35.75 minutes. The time of staying in the hospital was 3.52±1.14 days. Quality of life assessment after the surgery showed 46 very good and good cases 95.8% and 2 cases (4.2%) with satisfactory result. No case of bad outcome was recorded. Conclusion: Surgical treatment of inguinal hernia by the Mesh Plug technique is really effective, safe with faster postoperative rehabilitation, less postoperative pain, less complications, shorter hospital stay and early return to normal activities and work.

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