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1.
《Arabian Journal of Chemistry》2022,15(9):104086
In this paper, we studied commercially available precipitated rice husk silica (RHS) with conventional precipitated silica, which has nearly the same surface area, and replaced part of the carbon black with RHS and conventional silica in a basic tread formulation. All formulations were mixed with the same amount of filler during the study. Silica was used at 15, 30 and 50 phr loading, and part of the carbon black was replaced by silica. Compound curing characteristics, physical properties, rebound resilience, heat generation, abrasion loss, dynamic properties and morphology were analyzed. The results indicated that RHS demonstrated compound properties comparable to those of conventional silica. As part of the carbon black was replaced with conventional silica, a slower cure rate, higher rebound resilience, lower heat generation, lower abrasion loss, and lower tan delta were observed with no significant change in physical properties, but some changes in physical properties were observed using one way ANOVA analysis. We found the same trend when replacing part of the carbon black with RHS, such as a slower cure rate, higher rebound resilience, lower heat generation, lower abrasion loss, and lower tan delta with no significant change in physical properties, but some changes in physical properties were observed using one way ANOVA. This sustainable material could be used to replace conventional silica in tire compounding, as well as to replace a portion of carbon black with RHS for improved heat build-up, rolling resistance, and abrasion loss. 相似文献
2.
This paper proposes the Rice condition numbers for invariant subspace, singular sub-spaces of a matrix and deflating subspaces of a regular matrix pair. The first-order perturbation estimations for these subspaces are derived by applying perturbation expansions of orthogonal projection operators. 相似文献
3.
M.Z. Arslanov 《Operations Research Letters》2007,35(5):636-644
We consider the problem of guillotine cutting a rectangular sheet into two rectangular pieces without rotations. The question is whether there exists a cutting pattern with given numbers of occurrences of both rectangular pieces. A polynomial time algorithm is described to construct the convex hull of solutions to this problem. 相似文献
4.
M. D. Guay 《Acta Mathematica Hungarica》2004,105(3):241-248
Axioms are given for a preconvexity space and certain consequences obtained. In particular, it is shown that in a very natural
way, a preconvexity on a space yields an abstract convexity space in much the same manner as a proximity yields a topological
space.
This revised version was published online in June 2006 with corrections to the Cover Date. 相似文献
5.
The peeling of a d-dimensional set of points is usually performed with successive calls to a convex hull algorithm; the optimal worst-case convex hull algorithm, known to have an O(n˙ Log (n)) execution time, may give an O(n˙n˙ Log (n)) to peel all the set; an O(n˙n) convex hull algorithm, m being the number of extremal points, is shown to peel every set with an O(n-n) time, and proved to be optimal; an implementation of this algorithm is given for planar sets and spatial sets, but the latter give only an approximate O(n˙n) performance. 相似文献
6.
7.
L. Stachowicz S. K. Singh E. Wender S. L. Girshick 《Plasma Chemistry and Plasma Processing》1993,13(3):447-461
Heat-treated rice hulls have been used as precursor material for synthesis of ultrafne SiC in a RF plasma reactor. Rice hulls containing finely distributed silica and active carbon act as a source for SiC formation. The plasma-synthesized powder contained ultrafnc -SiC with excess carbon and some unreacted silica. Post-treatment processes such as oxidation and acid (HF) treatment appear to be effective in removing the excess carbon and silica. 相似文献
8.
Csar Ricardo Teixeira Tarley Srgio Luis Costa Ferreira Marco Aurlio Zezzi Arruda 《Microchemical Journal》2004,77(2):163-175
The use of rice husks as an alternative adsorbent in an on-line preconcentration system for Cd (II) and Pb (II) determination by flame atomic absorption spectrometry (FAAS) is described. The potential of rice husks as a natural adsorbent was evaluated as a material modified with 0.75 mol l−1 NaOH solution and in the unmodified form. For this task, several techniques such as spectroscopy and thermogravimetry were used for elucidation of possible functional groups responsible for the uptake of Cd (II) and Pb (II). Furthermore, based on adsorption studies and adsorption isotherms applied to the Langmüir model, it was possible to verify that modified rice husks present a higher adsorption capacity for both metals. After establishing this material as a promising natural adsorbent, it was used for on-line preconcentration of Cd (II) and Pb (II) metals. The multivariate optimisation of chemical and flow variables was performed by using a full factorial design (24) including the following factors: preconcentration time, preconcentration flow rate, concentration and volume of eluent. The optimum pH values used for on-line preconcentration were taken from prior univariate experiments. Under optimised conditions for Cd (II) determination (4 min of preconcentration at a 6 ml min−1 preconcentration flow rate, in which comprises 24 ml of preconcentration volume, 200 μl elution volume and 1.0 mol l−1 HNO3 solution as eluent), the system achieved a detection limit of 1.14 μg l−1 and an enrichment factor of 72.4. Similar conditions were used for Pb (II) determination (4 min of preconcentration, 6 ml min−1 preconcentration flow rate, 300 μl elution volume and 1.0 mol l−1 HNO3 solution as eluent) from which a detection limit of 14.1 μg l−1 and enrichment factor of 46.0 were achieved. Also, rice husks have been shown to be a homogeneous and stable adsorbent in which more than 100 preconcentration/elution cycles provide a relative standard deviation (RSD) of less than 6.0% on the analytical signal. The satisfactory accuracy of the method developed was obtained by using spiked water samples (mineral water and lake water) and spiked red wine samples. These values were confirmed by electrothermal atomic absorption spectrometry (ETAAS). The certified reference material [pig kidney (CRM 186)] and the reference material [beech leaves (CRM 100)] were also used. 相似文献
9.
Utilization of one waste material to control pollution caused by another is of high significance in the remediation of environmental
problems. Rice husk, an abundantly available agricultural waste, can be used as a low cost adsorbent for dyes and heavy metals
in effluent streams. The possible utilization of rice husk ash as an adsorbent for methylene blue dye from aqueous solutions
has been investigated. Ash samples from husks of two origins were prepared at different temperatures and their physical, chemical
spectroscopic and morphological properties were determined. XRD, FTIR and SEM were some of the techniques adopted for the
characterization. The samples were also analyzed for bulk density, pH, nitrogen adsorption properties and lime reactivity.
Experiments of methylene blue adsorption on the ash samples were conducted using batch technique and a comparative study was
made. Results were analyzed using linear, Langmuir and Freundlich isotherms. The values of separation factor indicate that
most of the ash samples do adsorb the dye molecules, but in varying quantities. Calcination at 900∘C reduces the adsorption capacity of the ash to a great extent. Regression analysis shows that the experimental data fits
both Langmuir and Freundlich isotherms for certain concentration limits. The adsorbate species are most probably transported
from the bulk of the solution into the solid phase through intra-particle diffusion process. Kinetics of adsorption was found
to follow pseudo second order rate equation with R
2∼ 0.99. The highest adsorption capacity (Q
0) achieved is found to be ∼690 mg/g, which is even higher than the values reported for activated carbon from rice husk. The
adsorption capacity of the ash samples are in good agreement with their surface area and pore volume. 相似文献
10.