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Different Cycles (different + cycle)
Selected AbstractsEffects of cyclic compression and thermal aging on dynamic properties of neoprene rubber bearingsJOURNAL OF APPLIED POLYMER SCIENCE, Issue 3 2008Hsoung-Wei Chou Abstract The dynamic properties of rubber bearings frequently used as isolators in structures could be significantly deteriorated because of the change of microstructure in rubber caused by cyclic compression and thermal aging. As a result, a catastrophic failure of bridges and buildings unexpectedly occurs when they are subjected to earthquake attack. Here, the dynamic properties of neoprene rubber bearings before and after different cycles of compressive loading or various periods of thermal aging were first measured and compared to each other. On the basis of the experimental results, the effects of cyclic compression and thermal aging on the stiffness, energy absorption, and equivalent viscous damping coefficient of neoprene rubber bearings are investigated. It is found that the deterioration of dynamic properties of neoprene rubber bearings caused by either cyclic compression or by thermal aging is significant and should be taken into account in designing rubber bearings. © 2007 Wiley Periodicals, Inc. JAppl Polym Sci, 2008 [source] Influence of novel cycle concepts on the high-temperature corrosion of power plantsMATERIALS AND CORROSION/WERKSTOFFE UND KORROSION, Issue 5 2008Bettina BordenetArticle first published online: 29 MAY 200 Abstract The aim to reduce CO2 emissions has triggered the evaluation of new cycle concepts for power plants. CO2 -capture concepts are also evaluated to add on new and existing power plants. For combined cycle power plants (CCPP), different cycles are investigated such as integrated gasification (IGCC) or oxy-fuel firing. Besides the difference in combustion compared to a conventional CCPP, the environmental boundary conditions are changed and will affect the oxidation and corrosion life of the materials in the hot-gas path of the gas turbine and the heat-recovery steam generator. For the circulating fluidised bed power plants, the biomass co-firing and the oxy-fuel firing are also foreseen for CO2 -emission reduction. The fireside corrosion of the water walls will be influenced by these concepts and the changed fuel. The corrosion risk has been evaluated for two new power plant concepts: combined cycle with exhaust gas recirculation and pulverised coal-fired boiler with oxy-fuel firing. Based on this evaluation, the consequences for the testing conditions and the material selection have been discussed in detail. [source] Perpetuation of subgingival biofilms in an in vitro modelMOLECULAR ORAL MICROBIOLOGY, Issue 1 2010L.M. Shaddox Summary This study evaluated the reproducibility of in-vitro -grown biofilms, initiated with subgingival plaque from patients with periodontal disease, and continued through several cycles by re-inoculating new biofilms from previously grown biofilms. Subgingival plaque samples from bleeding pockets along with saliva samples were collected from three patients with chronic periodontitis and perpetuated through seven cycles. Calcium hydroxyapatite disks were coated with sterilized saliva inoculated with dispersed subgingival plaque. The biofilms were grown anaerobically at 37°C for 10 days, and at specific intervals total viable bacteria were enumerated and the species present were analysed by DNA,DNA checkerboard hybridization. All cycles of biofilm growth occurred at similar rates and reached steady-state at day 7. No statistically or microbially significant differences were found for viable counts or species present, at the same period of maturation, among the different cycles. This study demonstrated that growth of certain target subgingival periodontal species in this biofilm model was reproducible and could be perpetuated in vitro through several cycles. The model could be useful in future studies to characterize different periodontopathogenic properties and biofilm interactions, especially in recolonization studies. [source] Measuring Synchronization and Convergence of Business Cycles for the Euro area, UK and US,OXFORD BULLETIN OF ECONOMICS & STATISTICS, Issue 1 2008Siem Jan Koopman Abstract This paper investigates business cycle relations among different economies in the Euro area. Cyclical dynamics are explicitly modelled as part of a time series model. We introduce mechanisms that allow for increasing or diminishing phase shifts and for time-varying association patterns in different cycles. Standard Kalman filter techniques are used to estimate the parameters simultaneously by maximum likelihood. The empirical illustrations are based on gross domestic product (GDP) series of seven European countries that are compared with the GDP series of the Euro area and that of the US. The original integrated time series are band-pass filtered. We find that there is an increasing resemblance between the business cycle fluctuations of the European countries analysed and those of the Euro area, although with varying patterns. [source] Cyclical feed deprivation and refeeding fails to enhance compensatory growth in Nile tilapia, Oreochromis niloticus L.AQUACULTURE RESEARCH, Issue 2 2009Yan Wang Abstract A 12-week experiment was carried out to evaluate compensatory growth of 6.6 g Nile tilapia Oreochromis niloticus L. under three cyclical regimes of feed deprivation and refeeding. The deprivation and refeeding regimes included four cycles of 1 week of deprivation and 2 weeks of refeeding (S1F2), two cycles of 2 weeks of deprivation and 4 weeks of refeeding (S2F4) and one cycle of 4 weeks of deprivation and 8 weeks of refeeding (S4F8). A group of fish fed to satiation twice daily throughout the experiment served as control. At the end of the refeeding periods, fish deprived and refed cyclically had higher feed intake and specific growth rates (SGR), but lower body weight, than that of the control fish. There was no significant difference in feed efficiency ratio (FER) between the control and fish subjected to feed deprivation during the refeeding periods, and nitrogen retention efficiency (NRE) was not different between any two treatments throughout the experiment. At the end of the experiment, fish subjected to feed deprivation had lower body weight but similar body composition, relative to those of the control fish. No significant differences were found in final body weight, NRE and body composition between the fish subjected to different cycles of deprivation and refeeding, but the fish subjected to one cycle of deprivation and refeeding exhibited high mortality. Our results indicate that partial growth compensation induced by various cycles of feed deprivation and refeeding does not confer a huge advantage in terms of enhancing the production efficiency and reducing the nitrogen waste output in Nile tilapia farming 29,30 °C. [source] Basic Types and Structural Characteristics of Uplifts: An Overview of Sedimentary Basins in ChinaACTA GEOLOGICA SINICA (ENGLISH EDITION), Issue 2 2009Dengfa HE Abstract: The uplift is a positive structural unit of the crust It is an important window for continental dynamics owing to its abundant structural phenomena, such as fault, fold, unconformity and denudation of strata. Meanwhile, it is the very place to store important minerals like oil, natural gas, coal and uranium. Giant and large-scale oil and gas fields in China, such as the Daqing Oilfield, Lunnan-Tahe Oilfield, Penglai 19,3 Oilfield, Puguang Gas Field and Jingbian Gas Field, are developed mainly on uplifts. Therefore, it is the main target both for oil and gas exploration and for geological study. The uplift can be either a basement uplift, or one developed only in the sedimentary cover. Extension, compression and wrench or their combined forces may give rise to uplifts. The development process of uplifting, such as formation, development, dwindling and destruction, can be taken as the uplifting cycle. The uplifts on the giant Precambrian cratons are large in scale with less extensive structural deformation. The uplifts on the medium- and small-sized cratons or neo-cratons are formed in various shapes with strong structural deformation and complicated geological structure. Owing to changes in the geodynamic environment, uplift experiences a multi-stage or multi-cycle development process. Its geological structure is characterized in superposition of multi-structural layers. Based on the basement properties, mechanical stratigraphy and development sequence, uplifts can be divided into three basic types , the succession, superposition and destruction ones. The succession type is subdivided into the maintaining type and the lasting type. The superposition type can be subdivided into the composite anticlinal type, the buried-hill draped type, the faulted uplift type and the migration type according to the different scales and superimposed styles of uplifts in different cycles. The destruction type is subdivided into the tilting type and the negative inverted type. The development history of uplifts and their controlling effects on sedimentation and fluids are quite different from one another, although the uplifts with different structural types store important minerals. Uplifts and their slopes are the main areas for oil and gas accumulation. They usually become the composite oil and gas accumulation zones (belts) with multiple productive formations and various types of oil and gas reservoirs. [source] | |||||||||||||