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1.
2.
The removal of Cu(II) by adsorption on fly ash has been found to be concentration, pH and temperature dependent. The kinetics of adsorption indicates the process to be diffusion controlled. The Langmuir constants have been calculated at different temperatures, and the adsorption has been found to be endothermic (ΔH = 15.652 kcal mol?1). The maximum removal is observed at pH 8.0, and variation in adsorption with pH has been explained on the basis of surface ionisation and complexation. 相似文献
3.
4.
V. S. Anil Kumar Madhav V. Marathe Srinivasan Parthasarathy Aravind Srinivasan 《Algorithmica》2009,55(1):205-226
We present polylogarithmic approximations for the R|prec|C
max and R|prec|∑
j
w
j
C
j
problems, when the precedence constraints are “treelike”—i.e., when the undirected graph underlying the precedences is a
forest. These are the first non-trivial generalizations of the job shop scheduling problem to scheduling with precedence constraints
that are not just chains. These are also the first non-trivial results for the weighted completion time objective on unrelated
machines with precedence constraints of any kind. We obtain improved bounds for the weighted completion time and flow time for the case of chains with restricted assignment—this
generalizes the job shop problem to these objective functions. We use the same lower bound of “congestion + dilation”, as
in other job shop scheduling approaches (e.g. Shmoys, Stein and Wein, SIAM J. Comput. 23, 617–632, 1994). The first step in our algorithm for the R|prec|C
max problem with treelike precedences involves using the algorithm of Lenstra, Shmoys and Tardos to obtain a processor assignment
with the congestion + dilation value within a constant factor of the optimal. We then show how to generalize the random-delays
technique of Leighton, Maggs and Rao to the case of trees. For the special case of chains, we show a dependent rounding technique
which leads to a bicriteria approximation algorithm for minimizing the flow time, a notoriously hard objective function.
A preliminary version of this paper appeared in the Proc. International Workshop on Approximation Algorithms for Combinatorial Optimization Problems (APPROX), pages 146–157, 2005.
V.S. Anil Kumar supported in part by NSF Award CNS-0626964. Part of this work was done while at the Los Alamos National Laboratory,
and supported in part by the Department of Energy under Contract W-7405-ENG-36.
M.V. Marathe supported in part by NSF Award CNS-0626964. Part of this work was done while at the Los Alamos National Laboratory,
and supported in part by the Department of Energy under Contract W-7405-ENG-36.
Part of this work by S. Parthasarathy was done while at the Department of Computer Science, University of Maryland, College
Park, MD 20742, and in part while visiting the Los Alamos National Laboratory. Research supported in part by NSF Award CCR-0208005
and NSF ITR Award CNS-0426683.
Research of A. Srinivasan supported in part by NSF Award CCR-0208005, NSF ITR Award CNS-0426683, and NSF Award CNS-0626636. 相似文献
5.
Madhav P. Yadav Gary D. StrahanSudarsan Mukhopadhyay Arland T. HotchkissKevin B. Hicks 《Food Hydrocolloids》2012,26(2):326-333
Corn fiber arabinoxylan is hemicellulose B isolated from the fibrous portions (pericarp, tip cap, and endosperm cell wall fractions) of corn kernels and is commonly referred to as corn fiber gum (CFG). Our previous studies showed that CFG isolated from corn bran (a byproduct of corn dry milling) contains very little protein and is an inferior emulsifier for oil-in-water emulsion systems as compared to corn fiber gum isolated from corn fiber derived from the corn wet-milling process. The protein deficient CFG isolated from corn bran was covalently conjugated with byproducts of cheese processing, β-lactoglobulin (β-LG) and whey protein isolate (WPI) using an economical food-grade Maillard-type heating reaction for the purpose of increasing their commercialization potential as a food emulsifier and soluble nutritional additive in beverages. The formation of the CFG-protein conjugates has been confirmed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE). It has also been demonstrated that CFG-protein conjugates are capable of producing fine emulsions with better stability than either CFG or protein alone. The molecular characterization of CFG-protein conjugates was performed by high-performance size-exclusion chromatography (HPSEC) coupled to on-line multi-angle laser light scattering and viscometric detection. The analysis by HPSEC revealed that CFG-protein conjugates had higher weight-average molar mass (Mw, 340-359 kDa) and polydispersity (Mw/Mn, 1.74) than the corresponding unconjugated CFG (Mw, 290 kDa and Mw/Mn, 1.35). The z-average root-mean-square radius of gyration (Rgz) of CFG-protein conjugates was slightly higher (30.5-33.5 nm) in comparison to CFG (29.5 nm) but their weight-average-intrinsic viscosity (η) remained unchanged (about 1.32 dL g−1). The Mark-Houwink exponent “a” of conjugates (0.40) was lower than the unconjugated CFG (0.53) indicating the formation of a more compact structure after conjugation with protein. These findings should benefit the beverage industry, which can use this information to produce a high quality emulsifier from the low-value byproducts of corn dry milling and cheese processing. 相似文献
6.
Justin R. Finn Janine E. Galvin Rupen Panday Huda Ashfaq 《American Institute of Chemical Engineers》2020,66(5):e16905
Microcapsules filled with liquid solvents for CO2 absorption can be easily deformed due to their elastic polymer shells. We present a combination of experiments and model predictions to demonstrate that modest compressive forces can lead to significant capsule deformation and performance issues for this enabling technology. Contrary to expectations based on Raoult's law, capsules containing aqueous carbonate solution were found to lose water to flows of humidified nitrogen in centimeter-scale packed beds. Water loss increased with gas velocity, suggesting compression was responsible for mass transfer, an interpretation supported by microscope images of deformed and broken capsules. A model for compression induced mass transfer under packed/fluidized bed operating conditions was developed and validated with the experimental data for a range of conditions (gas velocities, temperatures, humidities). Design criteria for future generations of microcapsules that will more effectively resist compression are evaluated. 相似文献
7.
J. A. Black V. Sivakumar M. R. Madhav G. A. Hamill 《Canadian Metallurgical Quarterly》2007,133(9):1154-1161
This paper investigates the performance of stone columns in a weak deposit such as peat. It evaluates the effects of reinforcing stone columns by jacketing with a tubular wire mesh and bridging reinforcement with a metal rod and a concrete plug. A series of plate loading tests was conducted on isolated stone columns installed in a soil bed consisting of a peat layer sandwiched between two layers of sand. The load–displacement characteristics of footings supported by stone columns were investigated by applying load to a circular plate supported on: (a) untreated soil; (b) soil treated with stone columns; and (c) soil treated with stone columns reinforced with the above reinforcing techniques. The work has shown that the settlement characteristics of the soil can be improved by installing stone columns and that a significant enhancement in the load–settlement response is achieved when the columns are reinforced by the various methods. 相似文献
8.
Madhav Prasad Neupane Yu Kyoung Kim Il Song Park Sook Jeong Lee Min Ho Lee Tae Sung Bae 《Metals and Materials International》2008,14(5):607-613
This study examines the surface morphology, microstructure, and chemical composition of titanium surfaces treated by anodic
spark oxidation in phosphate buffer solution at pH 2, 7 and 12. The pH of the electrolyte was found to play a substantial
role in the formation of different morphologies, chemical compositions, and pore dimensions with microporous structures. SEM
revealed variation in the topologies of the anodized surface with electrolyte pH. Porous structures with uniform pores and
high roughness were obtained in pH 12 solutions. However, intense anatase crystal was obtained at pH 7. The relationship between
surface characteristics of titanium and initial interactions of titanium-osteoblasts was also in vestigated. Our findings
demonstrated the cell viability and proliferation on the anodic oxides produced at pH 12 to be superior to those produced
at pH 2 and 7 as well as on the control titanium surface. This study also provides evidence of enhanced osteoblast adhesion
on anodized metal substrates under in vitro conditions. 相似文献
9.
As a new approach, LiFePO4 nanoparticles were directly synthesized from precursors iron(III) nitrate and lithium dihydrogen phosphate by a polyol process without post heat treatment in one step. The obtained powders were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and combined thermogravimetry and differential scanning calorimetry and mass spectroscopy TG/DSC/MS. The X-ray diffraction showed the orthorhombic crystal structure of LiFePO4 without any impurity phases. The synthesized LiFePO4 has rhombohedral morphology with high aspect ratio with a thickness of less than 100 nm. TG/DSC/MS revealed a weight loss of only 10.9 wt.% when heating up to 1000 °C. Electrodes prepared from the LiFePO4 particles were electrochemically characterized by cycling at 0.1C current rate and temperatures in half cell measurements against lithium foil between 2 and 4.2 V in an EC/DMC electrolyte with 1 M LiPF6 as conductive salt. A reversible specific capacity of 146 mAh/g was achieved by applying carbon coating on the rhombohedral particles. 相似文献
10.
VR Panday WW ten Bokkel Huinink H Rosing FJ Koopman MJ Hillebrand RC Dubbelman O van Tellingen JH Schellens JH Beijnen 《Canadian Metallurgical Quarterly》1998,9(8):665-673
Doxorubicin and paclitaxel both display strong antitumor activity in the treatment of breast cancer. The optimal schedule of this combination, however, remains undefined. In this phase I and pharmacologic study, we administered weekly 12 mg/m2 doxorubicin as a bolus infusion immediately followed by a 1 h 80 mg/m2 paclitaxel infusion to patients with metastatic breast cancer. A total of 119 weekly courses were delivered to seven patients. Grade IV neutropenia was observed in two patients at the first dose level, thus already defining the maximum tolerated dose. Pronounced non-hematologic toxicities were mild neuropathy (grade I: 39%) and stomatitis (grade I: 19%, grade II: 8%). No signs of cardiac toxicity were observed with this dose schedule. Three partial responses were achieved in this group of heavily pretreated patients. The pharmacokinetics of paclitaxel, doxorubicin and Cremophor EL with this schedule were analyzed. Overall, the schedule was well tolerated and combined with its preliminary response rate justifies further evaluation in phase II studies. 相似文献