Search Options

Sort by:

Sort search results by

Publication Type:

Publication Type filter

Open access:

Publication Date:

Periodicals:

Periodicals filter

Search results

Online since: September 2017
Authors: Yulia Efimova, V.L. Steblyanko, Anton P. Ponomarev
A number of units and laboratory facilities are created in the Laboratory of layered composites and coatings: 1.
High operational properties of coatings formed by plasma-electrolytic method are confirmed by a number of other authors [3, 16-18].
The authors note that the coatings are characterized by increased roughness and homogeneous structure with uniformly distributed spherical grains.
Along with the above it has been determined a number of other operational properties associated with high values of bonding strength to the substrate and density of plasma-electrolytic coatings.
This index is equal to the number of 1-minute immersions of the sample in the solution until areas covered by copper is emerged that are not removed after wiping with cotton or rag.
Online since: July 2016
Authors: Harald Schmidt
In contrast to experiments with Nuclear Magnetic Resonance Spectroscopy and Impedance Spectroscopy, only a limited number of tracer based experiments can be found in the literature.
In contrast, with macroscopic tracer methods it is possible to detect long range diffusion processes with a large number of jumps.
This technique is especially sensitive to light elements with atom numbers below 20, like Li.
There, the reflectivity R (the number of incoming neutrons divided by the number of reflected neutron) is plotted as a function of the scattering vector qz = 4 p/l sin(q).
Using SIMS on these samples, the lithium chemical diffusion coefficients in bulk and in grain boundaries were determined at room temperature as D = 1.23 × 10−15 m2/s and Dd = 6.55 × 10−20 m3/ s, respectively.
Online since: February 2020
Authors: Abhishek Kumar, Amritendu Roy
Small, stand-alone electronic devices which are growing in numbers in next generation smart cities, can be powered by scavenging energy from sources which would otherwise remain unused, such as mechanical vibrations.
Therefore a number of studies in past few years have found the operation and utilization of ceramic-polymer based piezoelectric composite material for energy harvesting based on the principles of piezoelectricity.
Cao, “Electromechanical Properties of Fine-Grain, 0. 7 Pb (Mg 1 / 3 Nb 2 / 3 ) O 3 -0 . 3PbTiO 3 Ceramics,” pp. 1–4, 2004
Online since: June 2025
Authors: Jindřich Viliš, Jan Zouhar, Roman Vítek, Tomáš Fornůsek, Zdeněk Pokorný
Currently, a number of researchers are investigating additive manufacturing technologies.
The microstructure of the wear-resistant steel MCH (Fig. 1b) is composed of fine-grained martensite.
In contrast, a significant number of pits and voids were observed on the fracture surfaces of the MCH sample (Fig. 6c and Fig. 6d), which is typical of ductile fracture primarily controlled by the coalescence of microcavities.
The MCH sample, which features a fine-grained martensitic microstructure, achieved the highest hardness of 504.2 HV 1, providing higher ballistic resistance compared to the other samples.
Online since: November 2011
Authors: Jia Xin Li, Ru Fei Wei, Guang Wu Tang
Their chemical compositions and grain-size distributions were listed in table 1, table 2 and figure 1, respectively.
Pellets naturally fell on the 10mm thick sheet steel from 1m height repeatedly until the pellet cracks down, the number of N times was recorded, and the N-1 fall times was named as pellets drop number.
Finally, after removing the maximum and minimum values, the average of 10 pellets falling number was viewed as drop strength.
Table 3 IR bands of phenolic resin and its functional groups Wave number (cm-1) Assignment Notes 3500 Phenolic —OH stretch a differs with b, c here 3025 Aromatic C—H stretch a differ with b, c here 2925 C—H stretch a different b, c here 1608, 1595, 1505 Aromatic C=C stretch a differs with b here 1104, 1150 Aromatic C—H in-plane deformation a differs with c here 887, 827, 756 Aromatic C—H Out-of-plane deformation a differs with b, c here 3025 Aromatic C—H stretch a differs with b, c here 1650 Aromatic C=O stretch 1451, 1364 CH2 deformation 1238 C—O stretch, O—H deformation IR bands of phenolic resin are shown in Table 3.
Online since: March 2014
Authors: Lian Tao Lu, Dong Fang Zeng
A counter recorded the number of revolutions.
This indicates the existence of refined grain[6], arising from rapid solidification of the melt due to high cooling rates experienced in laser process, which can increase the hardness of the glazed regions.
Wear test result Wear rate (weight loss per meter) of wheel disc is plotted in Fig. 5 against number of rolling cycles.
It can be seen that wear rate of treated wheel disc reaches the maximum at around 10 000 cycles, thereafter decreasing with number of rolling cycles until around 20 000 cycles, where the stable wear rate is reached for the remainder of the test.
Fig. 5 Relationship between the wear rate of wheel discs and number of rolling cycles.
Online since: January 2005
Authors: Jung Ho Ahn, H.K. Liu, G.X. Wang, Yong Jin Kim
It was reported [5] that the degree of reversibility of the anode materials is closely linked with the particle or grain size of the starting materials.
Instead, it is thought that they can be very effectively used as an additive to carbon anode materials to enhance both electrical conductivity and lithium storage capacity. 0 5 10 15 20 25 0 50 100 150 200 250 300 350 400 450 500 550 600 Cycle number Discharge capacity (mAh/g) Fig. 4: The discharge versus cycle number capacity for a Ag nanopowder electrode, produced by reverse micelle method. 20 nm For tin oxide electrode, Sn(OH)4 powders were first prepared by the same method of reverse micelle, followed by thermal decomposition to obtain SnO2 nanopowders.
Scanning rate: 0.1 mV/s. 0 5 10 15 20 25 0 100 200 300 400 500 600 700 800 900 1,000 Cycle number Discharge capacity (mAh/g) Fig. 8: Discharge capacity of a SnO2 nanopowder electrode versus cycle number.
Online since: April 2013
Authors: Carlos A. Gutiérrez-Chavarría, Jose Luis Rodríguez-Galicia, M. León-Carriedo
From this perspective, one of the design philosophies used to trigger the onset of reinforcement mechanisms is to generate compressive stresses within the material [7], therefore, the variables that should be taken into account for the analytical determination of the stresses residual and therefore the design of layered materials are as follows: thermal expansion coefficients, phase transformations or chemical reactions, number of layers, thickness and Young's modulus of material or materials used to form the layered ceramic component.
However, the zircon particles are substantially larger than the alumina, therefore these large particles may act as stress concentrators cracking the zircon particles and causing cleavage points along the grain.
On the other hand, the parameters to be taken into account in the design of the multilayered materials are the thermal expansion coefficient, the Young's modulus, the number of layers in the material and thickness of these; based on these parameters it is possible to determine the residual stresses to be present in each layer.
In addition, is necessary to take into account that the Young's modulus and the thermal expansion coefficients are inherent characteristics of the materials and are not so easily manipulated, but the design of the multi-layered component can be modified based on the number of layers and thickness of these.
Thus, if the number of layers is very large and the thickness of the layers is the same, compression and tensile residual stress are of equal magnitude.
Online since: June 2014
Authors: Meiry Glaúcia Freire Rodrigues, Jocielys Jovelino Rodrigues, Gustavo Medeiros de Paula, Liliane Andrade Lima
The SBA-15 has enhanced hydrothermal stability, if compared to other ordered mesoporous silicas such as the MCM-41 type, and large surface area (600–1000 m2/g), which allows the dispersion of a large number of catalytically active species [4].
The FTS activity and C5+ hydrocarbon selectivity increased with the addition of Ru, which was attributed to the increased number of active sites resulting from higher reducibility and the synergistic effect of Ru and Co.
The increase in activity and selectivity were attributed to the higher number of active sites resulting from higher reducibility, as well as, the synergetic effect of Ru and Co.
This behavior depends on the coordination number of the metal with the OH groups and the length and angle between the metal ion binding to a silica surface.
Conclusions According to XRD, BET, and EDX results, the SBA-15 support has a structure that includes multi-level mesopores, crystallites, and grains within the original particles.
Online since: August 2021
Authors: Aleksey N. Shapovalov, Lilya A. Ayvazyan, Nadezhda K. Nikoli
Therefore, despite the large number of continuous steel casting studies [2-25], the study of casting technology and bloom quality in specific production conditions allows us to obtain new patterns and improve the production technology.
Quality of the macrostructure of a round bloom Macrostructure defects Range of variation, score Average value, score Allowable value of defect development, score % of templates with exceeding the allowed score* Central porosity 0.5-4.0 1.19 2.0 15.5 Axial liquation 1.0-2.5 0.99 2.0 0.5 Liquation strips and cross-sectional cracks 0.5-2.0 0.34 1.0 6.9 Liquation strips and axial cracks 0.5-3.0 0.42 1.0 18.5 * of the total number of templates studied - 11968 pcs.
Crack spreading within the round bloom occurs along the boundaries of the former austenitic grains.
Analysis of Casting Conditions Bloom quality is influenced by a large number of factors.
Casting parameters Parameter Range of variation Average value Number of melts, [pcs.] 2849 Chemical composition, [%] carbon 0.6-0.62 0.61 manganese 0.64-0.72 0.67 silicon 0.25-0.33 0.28 sulphur 0.002-0.010 0.003 phosphorus 0.005-0.020 0.010 nitrogen 0.004-0.008 0.072 hydrogen, ppm 0.7-2.0 1.4 Withdrawal speed, [m/min] 0.26-0.44 0.36 Spraying plan, [l/kg] 0.30 Steel temperature in the tundish, [ºC] 1490-1520 1500.5 Steel overheat in the tundish, [ºC] 15.4-45.6 26.7 The chemical composition of the steel meets the modern requirements of continuous casting, so the main problem in producing a quality billet is to maintain rational casting parameters.
Showing 24401 to 24410 of 28673 items