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81.
J. A. Schouten 《Mathematische Zeitschrift》1927,26(1):706-730
Ohne Zusammenfassung 相似文献
82.
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A procedure is explained to determined the amount of several pairs of diametrical loads applied to the outside boundary of
a ring when stresses at selected points of the inside or outside boundaries are known. Coefficients of influence are used,
following an approach similar to the one presented in a previous paper. Examples of application are given and the possible
increase in precision is shown when the number of points of measurements is larger than the number of loads to be determined. 相似文献
84.
This paper deals with inventory control in a class of M/G/1 queueing systems. At each point of time the system can be switched from one of two possible stages to another. The rate of arrival process and the service rate depend on the stage of the system. The cost structure imposed on the model includes both fixed switch-over costs and a holding cost at a general rate depending on the stage of the system. The rule for controlling the inventory is specified by two switch-over levels.Using an embedding approach, we will derive a formula for the long-run average expected costs per unit time of this policy. By an appropriate choice of the cost parameters, we may obtain various operating characteristics for the system amongst which the stationary distribution of the inventory and the average number of switch-overs per unit time. 相似文献
85.
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Natasja Schouten Louis G. J. van der Ham Gert-Jan W. Euverink André B. de Haan 《Adsorption》2007,13(5-6):523-532
Low cost adsorption technology offers high potential to clean up laundry rinsing water. From an earlier selection of adsorbents
(Schouten et al. 2007), layered double hydroxide (LDH) proved to be an interesting material for the removal of anionic surfactant, linear alkyl
benzene sulfonate (LAS) which is the main contaminant in rinsing water. The main research question was to identify the effect
of process parameters of the LDH synthesis on the stability of the LDH structure and the adsorption capacity of LAS. LDH was
synthesized with the co-precipitation method of Reichle (1986); a solution of M2+(NO3)2 and M3+(NO3)3 and a second solution of NaOH and Na2CO3 were pumped in a beaker and mixed. The precipitate that was formed was allowed to age and was subsequently washed, dried
and calcined. The process parameters that were investigated are the concentration of the initial solutions, M2+/M3+ ratio and type of cations. The crystallinity can be improved by decreasing the concentration of the initial solutions; this
also decreases the leaching of M3+ from the brucite-like structure into the water. The highest adsorption capacity is obtained for Mg2+/Al3+ with a ratio 1 and 2 because of the higher charge density compared to ratio 3. Storing the LDH samples in water resulted
in a reduction of adsorption capacity and a decrease in surface area and pore volume. Therefore, LDH is not applicable in
a small device for long term use in aqueous surroundings. The adsorption capacity can be maintained during storage in a dry
N2 atmosphere. 相似文献
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A. Schouten H. Mol C. Hamwijk J. C. Ravensberg K. Schmidt M. Kugler 《Chromatographia》2005,62(9-10):511-517
A straightforward method based on GC-MS was developed to determine the booster biocide dichlofluanid and its metabolite DMSA in sediment and water. Special attention was paid to conservation of samples, conversion of dichlofluanid to DMSA during analysis and the effect dichlofluanid-containing paint particles might have on the analysis results. The analytical method is suitable for the quantitative determination of dichlofluanid and its metabolite DMSA in seawater down to a level of 10 ng L-1. Dichlofluanid could not be detected in marine sediment as it was immediately degraded to DMSA. However, dichlofluanid could be determined as DMSA. The analytical method is suitable for the determination of DMSA in marine sediment down to 5 μg kg-1 (wet weight). 相似文献
90.