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31.
This paper assesses the influence of (differential) settlement on sewer system functioning. Based on historical data of the vertical position of sewer invert levels, tilt measurements and in-sewer inspection videos, settlement and settlement related influences are analyzed for a case study area in Amsterdam. The average settlement rate of this system was 4 mm/year. Given this settlement rate, it is shown that settlement significantly influences sewer system functioning within the lifetime of a sewer (system). 相似文献
32.
By varying cross-linking intensity, the effect of microbial transglutaminase on acid gels made from casein solution and raw milk was studied. To avoid any impact of heating, N-ethylmaleimide was used for enzyme inactivation after appropriately checking its efficiency. Up to a specific degree of oligomerisation gel stiffness and firmness increased and tan δ, time at gelation onset and syneresis decreased. Above approximately 70% and 25% of cross-linked protein in casein solution and raw milk, respectively, these parameters showed an opposite behaviour, and weak gels with high syneresis were obtained. Substrate differences, such as preferred cross-linking of adjoining κ-caseins on the surface of the micelle enhanced the effect of steric hindrance in raw milk and impaired proper rearrangements upon acidification at a much lower level of oligomerised protein. It is mainly dimeric and trimeric casein that successfully contributed to the enhanced properties of milk protein gels. 相似文献
33.
Prager L Mark G Mätzing H Paur HR Schubert J Frimmel FH Hesse S Schuchmann HP Schuchmann MN von Sonntag C 《Environmental science & technology》2003,37(2):379-385
The electron-beam (EB) degradation of volatile aromatics (benzene, toluene, ethylbenzene, xylenes: BTEX) in groundwater strip gas, which in the present work has been modeled by the introduction of the desired aromatic(s) to a stream of air or another gas, such as oxygen, is initiated essentially by the addition of *OH radicals to the aromatic ring, giving rise to hydroxycyclohexadienyl radicals, which form the corresponding peroxyl radicals upon addition of oxygen. As studied in some detail with benzene as a BTEX representative, various reactions of these lead to numerous oxidation products in a cascade of reactions, including the decomposition of products under the prevailing conditions of high turnover of the initial aromatic. Importantly, hydroxycyclohexadienylperoxyl radical formation is partly reversible, and the reactions of the hydroxycyclohexadienyl radicals, which thus have a significant presence in these systems, must therefore also be taken into consideration. In the gas phase, in contrast to the aqueous phase (see Part 1), the reactions of the hydroxycyclohexadienyl radicals lead to oligomeric products that appear to contribute, in addition to ionic clusters, to nucleation for the aerosols observed. Various nitrated products, among them nitrophenols, are observed when air is used for the stripping. However, these studies did not clear the pilot plant stage, since BTEX degradation using a bioreactor carried out in parallel was so successful that the EB technology was judged to be noncompetitive. As for the latter, expensive equipment consisting of a stripper, the EB machine, and an aerosol precipitator would be required. The condensed aerosols are biorefractory and would require further treatment for detoxification. 相似文献
34.
Clemens J. M. Lasance 《传热工程》2013,34(2):149-168
In order to reduce design-cycle time and physical prototyping, equipment manufacturers need to ascertain the thermal performance of new systems at the earliest possible stage of the design process. In the early 1990s, some European industries began to realize that the accurate prediction of the temperatures of critical electronic parts at the package, board, and system levels was seriously hampered by a lack of reliable, standardized input data that characterize the thermal behavior of these parts. It was the start of a number of European projects concerned with the creation and experimental calibration of thermal models for a range of electronic parts. The ultimate goal of these projects was to get component manufacturers to supply calibrated compact thermal models (CTMs) of their parts to end users by adopting the experimental techniques used to calibrate the detailed thermal conduction models of the parts and the methods to generate compact models. This review paper is written with the purpose of presenting a condensed overview of the history, background, philosophy, methodology, and standardization aspects of compact thermal modeling to non-experts. Some space is devoted to the basic concepts of thermal resistance and thermal characterization because many designers have an incorrect perception of the physics underlying these concepts. 相似文献
35.
In this study, three asset management strategies were compared with respect to their efficiency to reduce flood risk. Data from call centres at two municipalities were used to quantify urban flood risks associated with three causes of urban flooding: gully pot blockage, sewer pipe blockage and sewer overloading. The efficiency of three flood reduction strategies was assessed based on their effect on the causes contributing to flood risk. The sensitivity of the results to uncertainty in the data source, citizens' calls, was analysed through incorporation of uncertainty ranges taken from customer complaint literature. Based on the available data it could be shown that increasing gully pot blockage is the most efficient action to reduce flood risk, given data uncertainty. If differences between cause incidences are large, as in the presented case study, call data are sufficient to decide how flood risk can be most efficiently reduced. According to the results of this analysis, enlargement of sewer pipes is not an efficient strategy to reduce flood risk, because flood risk associated with sewer overloading is small compared to other failure mechanisms. 相似文献
36.
Lanying Sun Ling Wu Chongyun Bao Chunhua Fu Xinlong Wang Jinfeng Yao Xingdong Zhang Clemens A. van Blitterswijk 《Materials science & engineering. C, Materials for biological applications》2009,29(6):1829-1834
Osteo-inductive materials give rise to ectopic bone formation in vivo either in muscles or in subcutaneous tissue. However, the underlying molecular mechanism is totally unclear. To investigate the expression pattern of bone related genes in osteo-inductive materials, we performed quantitative PCR (qPCR) to detect the expressions of type I collagen, alkaline phosphatase (ALP) and bone morphogenetic protein 4 (BMP-4) in biphasic calcium phosphate (BCP) ceramics implanted in dorsal muscle of dogs. Bone formation in mandibular alveolus defects served as controls showing the expression patterns of these genes in natural healing bones. Histological examinations were performed to show the bone formation in osteo-inductive BCP implants. Data of qPCR indicated that all tested genes had a similar expression pattern with two peaks during the bone formation either in BCP implants or natural healing bones. Type I collagen and ALP were expressed at lower levels with delayed peak in BCP implant than that in natural healing bone. Higher BMP-4 expression level was detected in BCP ceramic implant than in natural healing bone at all the time points. These results demonstrated that expression patterns of bone-related genes in the inductive bone formation are similar to that of natural healing bone formation. As these three genes are important parameters for osteoblast activity in bone formation, our data provide clue to uncover the molecular mechanism of bone formation in osteo-inductive materials. 相似文献
37.
38.
Hans Korving Fran?ois H. L. R. Clemens Jan M. van Noortwijk 《Canadian Metallurgical Quarterly》2006,132(10):1076-1085
Sewage pumping stations represent an element of the sewer system, which is directly responsible for affecting serviceability; i.e., failing pumps may result in combined sewer overflows or flooding. However, failures of sewage pumps are not yet incorporated in sewer assessments due to lack of data. This paper presents the analysis of pump failure data provided by two sewer management authorities in The Netherlands. Pump failures have been studied accounting for the nature of the failures, the operation and maintenance procedures of the management authority, the aging of the pumps, and the changes in the environment of pumps. The analysis shows that sewage pumps fail relatively often due to the composition of sewage and the discontinuous operation of the pumps. The interarrival time and the duration of failures are highly variable and independent of the specific function of the pump. Resulting pump failure characteristics are applied in a Monte Carlo simulation to calculate the impact of failures on combined sewer overflow volumes. The results indicate that the serviceability of sewer systems is significantly affected by failing pumps. Therefore, including pump availability in sewer system assessments should be considered. 相似文献
39.
H Meziane JC Dodart C Mathis S Little J Clemens SM Paul A Ungerer 《Canadian Metallurgical Quarterly》1998,95(21):12683-12688
When administered intracerebroventricularly to mice performing various learning tasks involving either short-term or long-term memory, secreted forms of the beta-amyloid precursor protein (APPs751 and APPs695) have potent memory-enhancing effects and block learning deficits induced by scopolamine. The memory-enhancing effects of APPs were observed over a wide range of extremely low doses (0.05-5,000 pg intracerebroventricularly), blocked by anti-APPs antisera, and observed when APPs was administered either after the first training session in a visual discrimination or a lever-press learning task or before the acquisition trial in an object recognition task. APPs had no effect on motor performance or exploratory activity. APPs695 and APPs751 were equally effective in the object recognition task, suggesting that the memory-enhancing effect of APPs does not require the Kunitz protease inhibitor domain. These data suggest an important role for APPss on memory processes. 相似文献
40.
Clemens Bhne 《国际钢铁研究》1969,40(8):661-665
Verbesserung der Schwertklingen durch Damaszierung. Nachweis des Übergangs auf eine andere Schmiedetechnik in der Ritterzeit (11. bis 14. Jh.) an Hand von zwölf mittelalterlichen Schwertern, die aus in der Steiermark hergestellten Stählen nach der Gärbtechnik gefertigt wurden. Kennzeichnung des sogenannten Scharsachstahles mit rd. 0,80% C und seine Verarbeitung zu Schwertklingen mit hoher Elastizität. 相似文献