scholarly journals Study of Phase and Chemical Composition of Bi1-xNdxFeO3 Powders Derived by Pressureless Sintering

2013 ◽  
Vol 58 (4) ◽  
pp. 1371-1376 ◽  
Author(s):  
J. Dzik ◽  
A. Lisinska-Czekaj ◽  
A. Zarycka ◽  
D. Czekaj
Keyword(s):  
Weight Loss ◽  
Chemical Composition ◽  
Structural Phase ◽  
Simultaneous Thermal Analysis ◽  
Orthorhombic Symmetry ◽  
Pressureless Sintering ◽  
Oxide Powders ◽  
Neodymium Concentration ◽  
Temperature Ranges ◽  
Phase And Chemical Composition

Abstract In the present paper studies on Bi1-xNdxFeO3 for x =0.1-0.4 are reported. The mixed oxide method followed with pressureless sintering was employed for ceramics fabrication. Thermal behavior of stoichiometric mixtures of simple oxide powders, viz. Bi2O3, Nd2O3 and Fe2O3 was studied by simultaneous thermal analysis. It was found that with an increase in neodymium content the weight loss increased from 0.75% to 3.16% for x =0.1 and x =0.4, respectively. It was found that weight loss took place mainly within two temperature ranges, namely ΔT1 ≈(300-400)0C and ΔT2 ≈(600-800)°C. Bi1-xNdxFeO3 ceramics was studied in terms of its phase composition (X-ray phase analysis) and chemical composition (EDS method) at room temperature. It was found that Bi1-xNdxFeO3 suffered structural phase transition from rhombohedral to orthorhombic symmetry with an increase in neodymium concentration x within the range x =(0.2-0.3).

scholarly journals Effect of Bi2O3 Excess on Morphology and Structure of BiNbO4 Ceramics

2013 ◽  
Vol 58 (4) ◽  
pp. 1317-1321 ◽  
Author(s):  
D. Czekaj ◽  
A. Lisińska-Czekaj ◽  
K. Osińska ◽  
K. Biernacki
Keyword(s):  
Niobium Oxide ◽  
Elementary Cell ◽  
Orthorhombic Symmetry ◽  
Pressureless Sintering ◽  
Stoichiometric Mixture ◽  
Reaction Route ◽  
Cell Parameters ◽  
Oxide Powders ◽  
Solid State Reaction Route ◽  
The One

Abstract Goal of the present research was to fabricate BiNbO4 ceramics from the mixture of powders by the solid state reaction route and pressureless sintering at various temperatures (TS =8700C and TS =9100C) and study microstructure, phase composition and crystalline structure of BiNbO4 ceramics. Four batches were fabricated and examined, namely the one fabricated from the stoichiometric mixture of reagent - grade oxide powders, viz. Bi2O3 and Nb2O5 as well as the ones with an excess of 3%, 5% and 10% by mole of Bi2O3. It was found that apart from the main orthorhombic -BiNbO4 phase additional phases, namely tetragonal Bi5Nb3O15, and cubic Bi3NbO7 are possible to form from the mixture of bismuth oxide and niobium oxide. It was found that -BiNbO4 ceramics exhibited the orthorhombic symmetry identified as Pnna (52). However, small differences in elementary cell parameters were found for the samples sintered from stoichiometric and non-stoichiometric mixture of initial powders.

Analysis of Wear-Resistant Materials of Mixer - Pneumosuperchargers Blades Operating under Conditions of Abrasive Wear

2021 ◽  
Vol 316 ◽  
pp. 893-898
Author(s):  
Natalya Gabelchenko ◽  
Artem Belov ◽  
Artem Kravchenko ◽  
Oleg Kryuchkov
Keyword(s):  
Mechanical Properties ◽  
Weight Loss ◽  
Wear Resistance ◽  
Chemical Composition ◽  
Abrasive Wear ◽  
Abrasive Medium ◽  
Wear Resistant ◽  
Comparative Tests ◽  
Before And After ◽  
110G13l Steel

We conducted comparative tests of the wear resistance of metals operating under abrasive conditions. Samples were cut from the working parts of mixer-pneumosuperchargers. The chemical composition and mechanical properties were determined. To compare samples under abrasive wear conditions, we designed and assembled a carousel installation. The principle of its operation is based on mixing the abrasive medium by the samples being studied with a given speed. Wear resistance was evaluated by weight loss by samples after several test cycles. To determine changes in the structure of the metal during abrasive wear, metallographic studies of the samples were carried out before and after the tests. It is shown that the best complex of service and mechanical properties is possessed by 110G13L steel.

Fractionated Pyrolysis of Biomass and its Components

2014 ◽  
Vol 535 ◽  
pp. 734-737 ◽  
Author(s):  
Qian Liu ◽  
De Kui Shen
Keyword(s):  
Weight Loss ◽  
Rice Straw ◽  
Total Weight Loss ◽  
Wood Biomass ◽  
Thermogravimetric Analyzer ◽  
Dominant Component ◽  
Temperature Ranges ◽  
Biomass Components ◽  
Main Components ◽  
Pyrolysis Of Biomass

Fractionated pyrolysis of biomass and its three main components (viz. hemicellulose, cellulose and lignin) was carried out on a thermogravimetric analyzer, which effectively separated the pyrolysis progress of different compositions. Three temperature ranges of 40-300 °C, 300-400 °C and 400-700 °C were presented with hemicellulose, cellulose and lignin as the dominant component, respectively. Fir contains much more cellulose and lignin than rice straw, and thus the weight loss in 300-400 °C is much higher, as 66.4% of the total weight loss. Rice straw contains more extractives and hemicellulose, resulting in higher mass loss in the early pyrolysis stage of 40-300 °C. The pyrolysis of biomass was predicted by hemicellulose, cellulose and lignin according to the additivity law, and the fractionated pyrolysis showed good performance in the prediction of volatile and residue yields of wood biomass. The interactions of biomass components were revealed to be unneglectable.

Calorimetry, chemical composition and in vitro digestibility of sugarcane treated with calcium hydroxide

2018 ◽  
Vol 69 (4) ◽  
pp. 406
Author(s):  
Alexandre M. Dias ◽  
Luís C. V. Ítavo ◽  
Júlio C. Damasceno ◽  
Camila C. B. F. Ítavo ◽  
Geraldo T. Santos ◽  
...  
Keyword(s):  
Weight Loss ◽  
Chemical Composition ◽  
Calcium Hydroxide ◽  
Nutritive Value ◽  
Low Cost ◽  
Alkaline Treatment ◽  
In Vitro Digestibility ◽  
Cellulose Structure ◽  
High Dry Matter

Sugarcane is a source of roughage in animal feeding. It presents high production per unit of cultivated area, relatively easy cultivation and low cost of production per hectare, and better quality and a high dry matter (DM) yield in periods when forage is scarce. This study aimed to evaluate the effect of increasing levels of calcium hydroxide (Ca(OH)2) in sugarcane forage on chemical composition, in vitro digestibility values of DM, neutral detergent fibre (NDF) and acid detergent fibre (ADF), and kinetics of thermal decomposition processes of weight loss and heat flow. Sugarcane was collected close to the ground and 50-kg heaps of the fresh material were formed and mixed with four doses of Ca(OH)2 (0, 8, 16 and 24 g kg–1 sugarcane). Concentrations of NDF and ADF decreased linearly with increasing amount of Ca(OH)2, whereas concentration of hemicellulose increased linearly. In vitro digestibilities of DM, NDF and ADF were enhanced in a quadratic manner with increasing amounts of Ca(OH)2. The release of heat, measured by ΔH, increased linearly with increased Ca(OH)2 levels, likely due to enhanced digestibility of the fibre components. Weight loss decreased linearly between 272.2°C and 397.7°C with increased amounts of Ca(OH)2 added to sugarcane, likely due to changes in cellulose structure, which became denser and thermodynamically more stable than native cellulose following the alkaline treatment. Calcium hydroxide changed chemical composition and digestibility of the fibrous fraction of sugarcane, resulting in better nutritional value. The greatest release of heat and highest in vitro digestibility of fibre were observed when adding 15.2 g Ca(OH)2 kg–1 sugarcane; therefore, this dose is recommended to enhance the nutritive value of sugarcane as ruminant feed.

scholarly journals Structure of Alloys for (Sm,Zr)(Co,Cu,Fe)Z Permanent Magnets: First Level of Heterogeneity

Materials ◽  
2020 ◽  
Vol 13 (17) ◽  
pp. 3893 ◽  
Author(s):  
Andrey G. Dormidontov ◽  
Natalia B. Kolchugina ◽  
Nikolay A. Dormidontov ◽  
Yury V. Milov
Keyword(s):  
Phase Composition ◽  
Quantitative Analysis ◽  
Chemical Composition ◽  
Permanent Magnets ◽  
Composition Range ◽  
Structural Phase ◽  
High Coercivity ◽  
Structural Components ◽  
Structural Formation ◽  
Hysteretic Properties

An original vision for the structural formation of (Sm,Zr)(Co,Cu,Fe)Z alloys, the compositions of which show promise for manufacturing high-coercivity permanent magnets, is reported. Foundations arising from the quantitative analysis of alloy microstructures as the first, coarse, level of heterogeneity are considered. The structure of the alloys, in optical resolutions, is shown to be characterized by three structural phase components, which are denoted as A, B, and C and based on the 1:5, 2:17, and 2:7 phases, respectively. As the chemical composition of alloys changes monotonically, the quantitative relationships of the components A, B, and C vary over wide ranges. In this case, the hysteretic properties of the (Sm,Zr)(Co,Cu,Fe)Z alloys in the high-coercivity state are strictly controlled by the volume fractions of the A and B structural components. Based on quantitative relationships of the A, B, and C structural components for the (R,Zr)(Co,Cu,Fe)Z alloys with R = Gd or Sm, sketches of quasi-ternary sections of the (Co,Cu,Fe)-R-Zr phase diagrams at temperatures of 1160–1190 °C and isopleths for the 2:17–2:7 phase composition range of the (Co,Cu,Fe)–Sm–Zr system were constructed.

Effect of Chemical Composition of Glassy Phase of Porcelain Stoneware on Product Brittleness

2020 ◽  
Vol 989 ◽  
pp. 254-259
Author(s):  
Irina A. Pavlova ◽  
A.S. Kiyko ◽  
Elena Farafontova
Keyword(s):  
Chemical Composition ◽  
Brittle Failure ◽  
Glassy Phase ◽  
High Price ◽  
Firing Process ◽  
Small Object ◽  
Quenching Temperature ◽  
Floor Tiles ◽  
Increased Strength ◽  
Phase And Chemical Composition

During the operation of porcelain stoneware sometimes there is a type of defects associated with crumbling from the edge of tile. In addition, cracks occur when a small object is fallen and during transportation of the products. Compared to conventional ceramic floor tiles, porcelain stoneware has increased strength, which explains its high price. The brittle failure is most likely, due to the hardening of glassy phase of tiles during cooling stage of the firing process. As a rule, the quenching temperature depends on the chemical composition of the glassy phase formed during firing. Both the phase and chemical composition of porcelain stoneware, and the chemical composition of the glassy phase are determined.

scholarly journals Weight Loss Improves Cardio-Metabolic and Inflammatory State in Subjects with Metabolic Syndrome.

2020 ◽  
Vol 79 (OCE2) ◽  
Author(s):  
Matteo Della Porta ◽  
Gabriele Piuri ◽  
Micaela Garziano ◽  
Michela Barichella ◽  
Fulvio Muzio ◽  
...  
Keyword(s):  
Risk Factors ◽  
Metabolic Syndrome ◽  
Weight Loss ◽  
Chemical Composition ◽  
Weight Reduction ◽  
Inflammation Markers ◽  
Tnf Α ◽  
Cytokine Levels ◽  
Inflammatory State ◽  
Associated Risk Factors

AbstractMetabolic syndrome (MetS) is a condition characterized by a constellation of reversible major risk factors for cardiovascular disease (CVD) and type 2 diabetes (T2DM). While it has been widely demonstrated that weight reduction by 5–10% decreases CVD and T2DM risk factors, including atherogenic dyslipidemia, on the other hand, its effects on comprehensive serum cytokine profile and endotoxemia are less investigated. Furthermore, the impact of weight loss on these parameters was studied especially in subjects with morbid obesity, often after bariatric surgery; while the studies on the effects of a physiological weight reduction with a balanced hypocaloric diet in overweight and moderately obese subjects showed contradictory results.The aim of this pilot study was to investigate in overweight and obese men with MetS the effects of caloric restriction on the MetS-associated risk factors, chemical composition of lipoproteins and serum concentration of a wide spectrum of inflammation markers. In addition, the second purpose of this work was to study the possible correlation between lipoprotein chemical composition and these inflammation markers.Eighteen adult Caucasian males (25 kg/m2 < BMI < 35 kg/m2) with MetS losing at least 5% of their initial weight after six months of a Mediterranean-style balanced hypo-caloric diet were included in the study. Lipoproteins were isolated from plasma by ultracentrifugation in a discontinuous KBr gradient. Lipoprotein concentrations of proteins, cholesterol, phospholipids, and triacylglycerols were determined by colorimetric assays. Peripheral cytokine levels (IL-2, IL-6, IL-7, IL-8, IL-10, IL-12, IL-17, GM-CSF, MCP-1, MIP-1b, IL1-b, IL-4, IL-5, IL-13, G-CSF, INF-g, TNF-a) were determined by Bioplex multiplex immunoassay. Endotoxemia was measured by Limulus Amebocyte lysate assay. The effects of weight-loss were analysed by Wilcoxon's test, the correlations between covariates by Spearman's test (significance: p-value ≤ 0.05).After weight loss, we observed an improvement of MetS-associated risk factors and changes in lipoproteins composition. In particular, together with a reduction of triglyceridemia, we detected a massive transfer of triacylglycerols from HDLs toward LDLs. Furthermore, a significant decrease of IL-6 (0.9 ± 0.7 vs 0.5 ± 0.6), TNF-α (0.7 ± 0.3 vs 0.3 ± 0.18), IL-8 (1.6 ± 0.7 vs 1.3 ± 0.3) and MIP-1β (19.2 ± 1.5 vs 18.5 ± 1.5) was observed. Finally, peripheral levels of TNF-α and IL-8 were directly correlated with all lipid species of VLDL, whereas the concentration of MIP-1β and endotoxin with HDL lipids.Weight loss improved cardio-metabolic risk factors and decreased inflammatory state by reduction of cytokine levels. The relationships between lipoprotein composition and serum inflammation markers deserve to be deepened by studying broader populations.

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