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Online since: September 2011
Authors: Shun Quan Chen, Jing Chen, Ruxu Du
The numbers represent the performance: 1 – extremely poor; 2 – d poor; 3 – limited; 4 – good; 5 – extremely good.
Presently, there have been a number of successful commercial water treatment membranes.
For example, the AB-block copolymers composed of polybutadien-b-polyethylenoxid and its self-organization into a micelle with aggregation number of 8 are shown in Figure 3.
Fig. 3: AB-block copolymers composed of Polybutadien-b-polyethylenoxid and the self-organization into a micelle with aggregation number of 8.
Gas permeability measurements confirmed the highly porous nature of the films, but the lack of water permeability suggested that the nanochannels might be discontinuous on a macroscopic level, e.g. due to ‘grain boundaries’ in the film.
Online since: April 2014
Authors: Bo Lin
The medium copolymer PtBMA-b-PHEMA-SSZ and the final product of PtBMA-b-PHEMA-b-PDMAEMA had their number-average molecular weight of 1.95 × 104 g/mol and 4.4 × 104 g/mol with their corresponding polydispersity indexs 1.25 and 1.35, respectively.
GPC chromatographs (Fig. 3) shows that the linear triblock copolymer was prepared by controlled radical polymerization mediated with the RAFT process have an incremental growth of number-average molecular weight with the lapse of polymerization time and finally the number degree of polymerization of the polymer segment increased during the whole RAFT polymerization process as a result, indicating a living feature of polymerization.
Meanwhile, the number degree of polymerization of different segments in the triblock copolymer PtBMA-b-PGMA-b-PSt and PtBMA-b-PHEMA-b-PD MAEMA can be quantificationally evaluated by the H-NMR and structure can be determined when the integral intensity of aromatic signal at 7.9 ppm in the 1H-NMR was set as one unit (Table 1).
While the number-average molecular weight (Mn,GPC) and polydispersity index (PDI) were evaluated by the GPC chromatographs (Table 1).
The D band is activated in the first-order scattering process of sp2 carbons by the presence of in-plane substitutional heteroatoms, vacancies, grain boundary, or other defects and by finite size effects, all of which lower the crystalline symmetry of the quasi-infinite lattice [14].
Online since: August 2010
Authors: José Aarón Melo-Banda, F.E. Lugo del Ángel, R. Silva-Rodrigo, A. Vázquez Rodríguez, J. Navarrete Bolaños, R. García Alamilla, A. Castillo Mares, Eduardo Térres-Rojas, J.L. Rivera Armenta
Therefore, an alternative would be to invest in new and better technologies to guarantee gasoline free from polluting octane compounds such as additives, lead, tetraethyl and tert-butyl methyl ether through the n-hexane isomerization, which is an important reaction that allows a remarkable increase in the octane number (index that expresses the antidetonation power of a fuel) [1-2].
The crystallite size of the solid phase were evaluated on the basis of the Debye-Scherrer formula [9, 14], (τ = 0.9λ/βcos θ) where τ is the grain size of crystal, λ is the wavelength of the incident beam, β is the full width at half of the maximum of the diffraction band intensity and θ is half the Bragg angle.
The selectivity towards high octane number products increased with the addition of cerium oxide.
Conclusions The catalyst Pt/ZS10Ce, which is very active at low temperatures, is particularly useful in the isomerization of light petroleum fractions, to obtain products with high octane numbers.
With the increase of this oxide in the reaction of isomerization of n-hexane there is no coke formation and the products are more selective toward those with high octane number.
Online since: January 2005
Authors: Balázs Verő, Dénes Zsámbók, János Dobránszky, Ákos Horváth, László Kopasz, József Hirka
Typical fine grained HSLA-steel types of Danube Steelworks In 2003 Dunaferr Co.
The Fig. 7 clearly demonstrates that the number of papers on DP-steels is insignificantly low now, while the number of articles on TRIPsteels is growing rapidly.
Cooling route of TRIP steels after hot rolling 0 20 40 60 80 100 120 1970 1973 1976 1979 1982 1985 1988 1991 1994 1997 2000 2003 TRIP-steels D-P steels 0,6 0,8 1,0 1,2 1,4 1,6 1,8 0,05 0,10 0,15 0,20 PHZ 260 HX 180 DC 05 MHZ 420 MHZ 340 MHZ 260 DP-K 30/50 RA-K 40/70 HSZ 260 Poor deep-drawing Excellent stretching and deep-drawing Excellent stretching Hardening exponent, n Lankford-number, r Figure 7.
The classification of DP- and TRIP-steels on the basis of forming technique can be carried out primarily with the help of the stress strained curve, the Lankford-number and the plasticity determined by computing or measurement, as well as the comparison of these values with those of other materials.
Acknowledgement The National Scientific Research Foundation supported this research: project number is T43571.
Online since: June 2024
Authors: Khudhayer J. Jadee, Noor Alhuda Hayder Ali, Mohammed Ali Nasser
The Belleville spring was designed based on a number of considerations, including the following: i.
The number of discs in parallel (n) and the number of discs in series (i) make up an arrangement as illustrates the non-linearity of the arrangement load-length curves in Fig.4.
The typical calculation of (i) the number of springs placed in sequence without accounting for friction produces as follows.
Stress – Deflection Relation in Single Belleville Spring The Belleville spring discs can be subjected to extensive load, and it can be extending deeply inside the disc thickness, changing the grain size and giving its surface hardness.
In the proper computations of the stresses in the Belleville spring, tensile stress is represented by positive numbers, and compressive stress is represented by negative numbers.
Online since: May 2010
Authors: Paolo Scardi, Matteo Leoni, Matteo Ortolani
., twin and deformation faults), APB for Anti-Phase domain Boundaries, C for composition fluctuations, GRS for grain surface relaxation.
The minimization procedure proceeds with user-defined numbers of iterations.
This can be caused by a number of effects, among which lattice deformation (the so-called microstrain) due to defects.
It is interesting to conclude this discussion with a remark on the number of parameters used, and the general robustness of the procedure.
The limited number of parameters gives robustness to the algorithm and facilitates fast convergence to the best NLSQ result.
Online since: September 2007
Authors: Dezső L. Beke, Z. Erdélyi
Introduction Diffusion in nanostructures presents challenging features even if the role of structural defects (dislocations, phase- or grain-boundaries) can be neglected.
(1) In this exchange model Γi,i+1 is the probability per unit time that an A atom in layer i exchanges its position with a B atom in the layer i+1. zv is the vertical coordination number and ci denotes the atomic fraction of A atoms on plane i.
For the 0 0,2 0,4 0,6 0,8 1 0 10 20 30 number of layers atomic fraction of Ni t = 0 t > 0 Fig.6: Flux distribution and sharpening of an initially linear composition profile if the diffusion coefficient has strong composition dependence [14] 0 0.2 0.4 0.6 0.8 1 0 50 100 150 200 250 Number of layers Atomic fraction of A t=67t1 (b) 0 0.2 0.4 0.6 0.8 1 0 50 100 150 200 250 Number of layers Atomic fraction of A t=67t1 (b) 0 0.2 0.4 0.6 0.8 1 0 10 20 30 40 50 Number of layers Atomic fraction of A nβ(Xβ=anβ) nI nα cβ t=t1 (a) 0 0.2 0.4 0.6 0.8 1 0 10 20 30 40 50 Number of layers Atomic fraction of A nβ(Xβ=anβ) nI nα cβ t=t1 (a) case of semi-infinite geometry the first part of the intermixing (the initial sharpening and linear shift of the interface) will be extended to times under which the deposited film consumes.
The division of the composition profile into three regions is illustrated in a) [15]. 0 0.2 0.4 0.6 0.8 1 0 50 100 150 200 Number of layers Atomic fraction of A cβ 1-cβ 0 0.2 0.4 0.6 0.8 1 0 50 100 150 200 Number of layers Atomic fraction of A cβ 1-cβ where ∆c=-cβ.
For the thickness of the diffusion zone we can write X=Xα+XI+Xβ=nαa+nIa+nβa, where nα and nβ are the numbers of atomic planes along which the composition falls in the α and β phases on the left and right hand side of the interface, respectively.
Online since: May 2013
Authors: Ajay Kumar, Pankaj Kalra, Rajeev Garg
An open circuit voltage (OCV) of slightly larger than 1 volt is attained when the cell is not loaded and ionic transport number is close to 100%.
Very large grain-boundary resistances would prevent the free flow of oxygen anions if the oxide particles are simply pressed together at low temperatures.
In order to remove the grain-boundary resistance between YSZ particles typically a sintering temperature of at least 1500K is required.
The electrochemical reactions occur in an SOFC on a large number of active triple phase boundary (TPB) sites present in the porous mixed conducting electrodes.
Liquid hydrocarbons, e.g. propane, are also used for a number of stationary power generation applications because of their widespread availability.
Online since: February 2019
Authors: L.L. Maslennikova, N.A. Babak, I.A. Naginskii
For research of waste structure and synthesizable materials structure X-ray phase, differential-thermal methods of analysis and grain size measurements were used.
Determination of the size modulus of screening of secondary crushed stone Residues, [% by weight, on sieves #] Passage through the sieve with mesh # 016, [% by weight] Size modulus 2,5 1,25 0,63 0,315 0,16 [Мs] 19,5 17,7 16,6 16,7 18,0 11,5 2,7 Removing and recycling of fractions from 0 to 5mm from a secondary srush stone would allow to decrease an anthropogenic impact of construction waste on the environment. 2.2 Development of compositions of ceramic materials using construction waste Mineral construction waste in its chemical composition and technical properties are close to natural raw materials and sometimes they have a number of advantages (pre-heat treatment, increased dispersiveness and e.t.c.), so, the use of such wastes in the production of building materials is one of the ways of material intensity of production and environmental load decrease.
When a fine-dispersed clay-containing component is added to the composition, deformation characteristics of the material can be improved by changing of a structural motive of a contact at a prase boundary [3] and by an increase in the number of contacts Based on the conducted studies, a technology for the production of facade nonfired tiles was developed.
Online since: May 2017
Authors: Andini Isfandiary, Dyah Hikmawati, Prihartini Widiyanti
Tensile test data showed the highest number of tensile strength from the 0.1% AV sample at 0.017 MPa.
Methods Synthesis of Aloe vera Extract Mature Aloe vera was collected and separated from their skin (±400 grams), so only the clean and clear grains remained.
Collagen also found in numbers absorption 3250,25 cm-1 which is a cluster of O - H.
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