Academic literature on the topic 'Time-lag mechanism'
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Journal articles on the topic "Time-lag mechanism"
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Zhang, Yilin, Zhenyu Cheng, and Qingsong He. "Time lag analysis of FDI spillover effect." International Journal of Emerging Markets 15, no. 4 (November 1, 2019): 629–50. http://dx.doi.org/10.1108/ijoem-03-2019-0225.
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Purpose For the developing countries involving in the Belt and Road Initiative (BRI) with China as the main source of foreign development investment (FDI) and development as the top priority, it appears to attract more and more attention on how to make the best use of China’s outward foreign development investment. However, the contradictory evidence in the previous studies of FDI spillover effect and the remarkable time-lag feature of spillovers motivate us to analyze the mechanism of FDI spillover effect. The paper aims to discuss this issue. Design/methodology/approach The mechanism of FDI spillovers and the unavoidable lag effect in this process are empirically analyzed. Based on the panel data from the Belt and Road developing countries (BRDCs) and China’s direct investments (CDIs) from 2003 to 2017, the authors establish a panel vector autoregressive model, employing impulse response function and variance decomposition analysis, together with Granger causality test. Findings Results suggest a dynamic interactive causality mechanism. First, CDI promotes the economic growth of BRDCs through technical efficiency, human capital and institutional transition with combined lags of five, nine and eight years. Second, improvements in the technical efficiency and institutional quality promote economic growth by facilitating the human capital with integrated delays of six and eight years. Third, China’s investment directly affects the economic growth of BRDCs, with a time lag of six years. The average time lag is about eight years. Originality/value Based on the analysis on the mechanism and time lag of FDI spillovers, the authors have shown that many previous articles using one-year lagged FDI to examine the spillover effect have systematic biases, which contributes to the research on the FDI spillover mechanism. It provides new views for host countries on how to make more effective use of FDI, especially for BRDCs using CDIs.
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Xie, Hongming, Jie Yang, Wei Yu, Yingnan Yang, and Wenshi Wu. "The Time-lag Effect of R&D Investment on the Value of Listed Companies in China: A Cross-industry Analysis." Journal of Creating Value 6, no. 2 (September 10, 2020): 217–31. http://dx.doi.org/10.1177/2394964320923543.
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Innovation plays an increasingly important role in economic growth, and R&D investment has become a key component of innovation initiatives. In this study, we performed analyses of 58 listed automobile manufacturers and 52 listed Internet companies in China. The empirical analysis is carried out by using STATA15.0 to preliminarily explore the mechanism of the time-lag effect of R&D investment on the value of these companies over the years of time-lag as well as conduct comparison analyses across industries. The results show that R&D investment has a positive effect on corporate value and this effect has a long-term time-lag effect. The mechanism of time-lag effect of R&D investment on the corporate value over the lag years has significant differences across industries. The time-lag effect of R&D investment on the value of the listed automobile manufacturer presents an inverted U shape, while the time-lag effect of R&D investment on the value of the listed Internet companies decreases gradually. The study helps local government better understand the different mechanisms of the time-lag effect of R&D investment on the value of the listed companies and also serves as a reference for local government to make decisions on subsidies and other supportive policies for innovation initiatives of the listed companies.
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Gursul, Ismet. "Proposed Mechanism for Time Lag of Vortex Breakdown Location in Unsteady Flows." Journal of Aircraft 37, no. 4 (July 2000): 733–36. http://dx.doi.org/10.2514/2.2661.
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Man, Shuai. "Surface Settlement Time Lag Induced by Shield Tunneling in Urban Sandy-Pebble Stratum." Applied Mechanics and Materials 405-408 (September 2013): 1326–29. http://dx.doi.org/10.4028/www.scientific.net/amm.405-408.1326.
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This paper focuses on the surface settlement time lag caused by shield tunneling in sandy-pebble stratum in Chengdu. A surface collapse case during Chengdu metro construction was introduced and the mechanism of surface settlement time lag was analyzed. The process of the ground settlement was simulated using the UDEC software. It is found that: 1) over-excavation and the grouting failure are the root causes of surface settlement; 2) characteristics of the sandy-pebble stratum in Chengdu induce ground voids behind tunnel segmental lining; 3) the mechanism of surface settlement time lag can be explained by temporary ground arch in the sandy-pebble stratum.
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Zhang, M., Yun Huang, and L. Zhang. "Research on the Mechanism of Coordinate Polishing Crankshaft Crankpin with Abrasive Belt." Key Engineering Materials 487 (July 2011): 457–61. http://dx.doi.org/10.4028/www.scientific.net/kem.487.457.
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Under the conditions of crankshaft uniform rotation, the schematic diagram of coordinate polishing crankpin was analyzed and found that the grinding time and speech changed, when the abrasive grinded crankpin. At the same time, the surface roughness was the relevant with the grinding time, grinding for a long time the roughness value was low, grinding time was short then the roughness value was high. In order to ensure that the surface roughness was homogeneity, so that the abrasive grinded the grinding point in the same time, in other words, the abrasive grinded crankpin in the constant velocity. And then the abrasive grinding crankpin was analyzed in the constant velocity, the crankshaft angle was draw the relationship between horizontal displacement and the swing angle. Simultaneity, adopted the level cylinder and the oscillating cylinder mutual moving, that resulted in the mechanism following the rotation of crankshaft back and forth movement, it was due to the weight of mechanism and the lag of the cylinder, and finally the mechanism of lag error was analyzed.
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Young, Lydia M., Ling-Hsien Tu, Daniel P. Raleigh, Alison E. Ashcroft, and Sheena E. Radford. "Understanding co-polymerization in amyloid formation by direct observation of mixed oligomers." Chemical Science 8, no. 7 (2017): 5030–40. http://dx.doi.org/10.1039/c7sc00620a.
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Tzou, D. Y. "A Unified Field Approach for Heat Conduction From Macro- to Micro-Scales." Journal of Heat Transfer 117, no. 1 (February 1, 1995): 8–16. http://dx.doi.org/10.1115/1.2822329.
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A universal constitutive equation between the heat flux vector and the temperature gradient is proposed to cover the fundamental behaviors of diffusion (macroscopic in both space and time), wave (macroscopic in space but microscopic in time), phonon–electron interactions (microscopic in both space and time), and pure phonon scattering. The model is generalized from the dual-phase-lag concept accounting for the lagging behavior in the high-rate response. While the phase lag of the heat flux captures the small-scale response in time, the phase lag of the temperature gradient captures the small-scale response in space. The universal form of the energy equation facilitates identifications of the physical parameters governing the transition from one mechanism (such as diffusion or wave) to another (the phonon–electron interaction).
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Dolas, Ramdas T., Shalindra Sharma, and Madhuraj Sharma. "FORMULATION AND EVALUATION OF GASTRORETENTIVE FLOATING TABLETS OF LAFUTIDINE." Journal of Drug Delivery and Therapeutics 8, no. 5 (September 11, 2018): 393–99. http://dx.doi.org/10.22270/jddt.v8i5.1898.
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The purpose of this research was to develop a novel gastroretentive drug delivery system based on wet granulation technique for sustained delivery of active agent. Quick GI transit could result in incomplete drug release from the drug delivery system above the absorption zone leading to decreased efficacy of the administered dose and thus less patient compliance. Gastroretentive floating tablets, which was designed to provide the desired sustained and complete release of drug for prolonged period of time. Gastroretentive floating tablets of lafutidine were prepared by wet granulation technique using different concentrations of Gum Kondagagu, Gum olibanum and Locust bean Gum. The optimized formulation (LF14) exhibited 99.54% drug release in 12 hrs, while the buoyancy lag time was 33 sec. In-vitro drug release kinetics was found to follow both the Zero order and the possible mechanism of lafutidine release from the optimized formulation might be attributed to super case II transport mechanism. The Optimized formulation (LF14) showed no significant change in physical appearance, drug content, floating lag time, in vitro dissolution studies after 75%±5% RH at 40±20C relative humidity for 6 months.
Keyword: Wet granulation, Floating lag Time, Gastroretentive, Lafutidine
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Su, Hui, J. David Neelin, and Joyce E. Meyerson. "Mechanisms for Lagged Atmospheric Response to ENSO SST Forcing*." Journal of Climate 18, no. 20 (October 15, 2005): 4195–215. http://dx.doi.org/10.1175/jcli3514.1.
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Abstract The mechanism and sensitivity of the lagged response of tropical tropospheric temperature to El Niño–Southern Oscillation (ENSO) SST forcing are examined using the Quasi-Equilibrium Tropical Circulation Model (QTCM) coupled to a slab mixed layer ocean model, along with a simple analytical model. It is found that the lag and amplitude of tropospheric temperature response depend on mixed layer depth (MLD), ENSO SST forcing period, areal fraction of the mixed layer ocean, and the strength of Tropics to midlatitude transports. The phase lag is not a monotonic function of mixed layer depth. It maximizes at moderate MLD and, thus, is not very sensitive to MLD in the realistic range. The phase lag asymptotes to values determined by free-atmospheric time scales, between 1 and 2 months, for small or large values of MLD. The amplitude of the tropospheric temperature response decreases with increasing MLD. The phase lag and amplitude of tropospheric temperature both increase as a specified ENSO SST forcing period increases and they appear to be rather insensitive to the seasonal cycle of SST. On the other hand, the phase lag and amplitude of mixed layer ocean SST change monotonically with MLD and ENSO forcing period, with a deeper mixed layer producing longer lag and smaller amplitude of SST anomalies. Longer ENSO SST forcing periods correspond to longer lag and larger amplitude of mixed layer ocean SST anomalies. While the ENSO region convective heating (precipitation) anomalies are closely tied to SST anomalies, the tropical mean precipitation seems best viewed as a complex by-product of the response rather than as a driver. One useful parameter determining the lag of tropospheric temperature to ENSO SST is the freedecay time scale of the coupled system. This parameter combines the effects of surface flux exchanges, heat loss at the top of the atmosphere and from the Tropics to midlatitudes, and finite ocean heat capacity. It is indicative of the extent to which the lagged response of tropical tropospheric temperature to ENSO SST is a coupled phenomenon. Overall, the contribution of coupling to SST outside the ENSO region substantially increases the amplitude and lag of the tropospheric temperature response to ENSO.
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Peng, Shun Lei, Peng Li, and Wen Hui You. "Time Lag Effects and Rainfall Redistribution in Subtropical Evergreen Broad-Leaved Forest in Eastern Coastal China." Advanced Materials Research 864-867 (December 2013): 2224–31. http://dx.doi.org/10.4028/www.scientific.net/amr.864-867.2224.
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In order to reveal the ecological mechanism of rainfall redistribution and lag effects on precipitation of evergreen broad leaved forest in eastern coastal China, 25 m×25 m permanent plot studies were carried inC. fargesiistand andS. Superbastand in Forest Ecosystem Observation and Research station in Tiantong, Zhejiang Province. The results indicated that the total rainfall outside the forest was 5114.0 mm, the average rates of canopy interception, throuhfall, and stemflow were 24.5%, 6.1%, and 69.4% respectively inC. fargesiistand, which were 30.7%, 7.7%, and 61.6% respectively inS. Superbastand. Rainfall redistribution function ofC. fargesiistand was better than that ofC. fargesiistand. Throughfall and stemflow were increased with rainfall class increasing while canopy interception decreased as rainfall class increasing, especially during typhoon storm period. throughfall was observed after 67.6min when rainfall classes<5 mm happened, while throughfall was observed after 11.8 min when special heavy storm happened inC. fargesiistand, 6 times shorter than little rainfall event. The lag time of throughfall inS. Superbastand was longer than that in theC. fargesiistand. The time lag shortened gradually as rainfall class increased. Lag time of stemflow was about 2 times than that of throughfall.
Dissertations / Theses on the topic "Time-lag mechanism"
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Kumar, Ravi R. "NUMERICAL INVESTIGATION AND PARALLEL COMPUTING FOR THERMAL TRANSPORT MECHANISM DURING NANOMACHINING." UKnowledge, 2007. http://uknowledge.uky.edu/gradschool_theses/425.
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Nano-scale machining, or Nanomachining is a hybrid process in which the total thermal energy necessary to remove atoms from a work-piece surface is applied from external sources. In the current study, the total thermal energy necessary to remove atoms from a work-piece surface is applied from two sources: (1) localized energy from a laser beam focused to a micron-scale spot to preheat the work-piece, and (2) a high-precision electron-beam emitted from the tips of carbon nano-tubes to remove material via evaporation/sublimation. Macro-to-nano scale heat transfer models are discussed for understanding their capability to capture and its application to predict the transient heat transfer mechanism required for nano-machining. In this case, thermal transport mechanism during nano-scale machining involves both phonons (lattice vibrations) and electrons; it is modeled using a parabolic two-step (PTS) model, which accounts for the time lag between these energy carriers. A numerical algorithm is developed for the solution of the PTS model based on explicit and implicit finite-difference methods. Since numerical solution for simulation of nanomachining involves high computational cost in terms of wall clock time consumed, performance comparison over a wide range of numerical techniques has been done to devise an efficient numerical solution procedure. Gauss-Seidel (GS), successive over relaxation (SOR), conjugate gradient (CG), d -form Douglas-Gunn time splitting, and other methods have been used to compare the computational cost involved in these methods. Use of the Douglas-Gunn time splitting in the solution of 3D time-dependent heat transport equations appears to be optimal especially as problem size (number of spatial grid points and/or required number of time steps) becomes large. Parallel computing is implemented to further reduce the wall clock time required for the complete simulation of nanomachining process. Domain decomposition with inter-processor communication using Message Passing Interface (MPI) libraries is adapted for parallel computing. Performance tuning has been implemented for efficient parallelization by overlapping communication with computation. Numerical solution for laser source and electron-beam source with different Gaussian distribution are presented. Performance of the parallel code is tested on four distinct computer cluster architecture. Results obtained for laser source agree well with available experimental data in the literature. The results for electron-beam source are self-consistent; nevertheless, they need to be validated experimentally.
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Hörnfeldt, Birger. "Cycles of voles, predators, and alternative prey in boreal Sweden." Doctoral thesis, Umeå universitet, Ekologi och geovetenskap, 1991. http://urn.kb.se/resolve?urn=urn:nbn:se:umu:diva-100711.
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Bank voles, grey-sided voles, and field voles had synchronous 3-4 year density cycles with variable amplitudes which averaged about 200-fold in each species. Cycles of vole predators (red fox and Tengmalm's owl), and their (foxes') alternative prey (mountain hare and forest grouse) lagged behind the vole cycles. The nomadic Tengmalm's owl responded with a very rapid and strong numerical increase to the initial cyclic summer increase of voles (the owl’s staple food). Owl breeding densities in the springs were highly correlated with vole supply in the previous autumns. This suggested that the number of breeding owls was largely determined in the autumn at the time of the owl's nomadic migrations, and that immigration was crucial for the rapid rise in owl numbers. The owl's numerical response was reinforced by the laying of earlier and larger clutches when food was plentiful. In addition, the owl has an early maturation at one year of age. The transition between subsequent vole cycles was characterized by a distinct shift in rate of change in numbers from low to high or markedly higher values in both summer and winter. Regulation increased progressively throughout the cycle since the rate of change decreased continuously in the summers. Moreover, there was a similar decrease of the rate of change in winter. Rate of change was delayed density-dependent. The delayed density-dependence had an 8 month time-lag in the summers and a 4 month time-lag in the winters relative to the density in previous autumns and springs, respectively. These findings suggest that vole cycles are likely to be generated by a time-lag mechanism. On theoretical grounds, it has been found that a delayed density- dependence of population growth rate with a 9 month time-lag caused stable limit cycles with a period between 3 and 4 years. Some mechanisms for the delayed density-dependence are suggested and discussed. The mechanisms are assumed to be related to remaining effects of vole populations past interactions with predators, food supplies, and/or diseases. Unlike the other voles, the bank vole had regular and distinct seasonal declines in density over winter. These declines are proposed to be due to predation, mainly by Tengmalm's owl. Supranivean foraging for epiphytic tree lichens and conifer seeds most likely explains why this species was frequently taken by the owl under snow-rich conditions. The alternative prey hypothesis predicts that a reduction of predator numbers should increase the number of alternative prey. Alternative prey should be less effectively synchronized to the vole cycle by predation at declining and low vole (main prey) densities; they may also lose their 3-4 year cyclicity. The appearance of sarcoptic mange among foxes in northern Sweden in the mid 1970s provided an opportunity to "test" these ideas, and these were found to be supported. In areas with highest mange infection rates, foxes declined markedly from the late 1970s to mid 1980s, whereas hare numbers rose rapidly and appeared non-cyclic.Diss. (sammanfattning) Umeå : Umeå universitet, 1991, härtill 7 uppsatser
digitalisering@umu
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Berry, Jeff. "Mechanisms of short-lag voice onset time." 2000. http://catalog.hathitrust.org/api/volumes/oclc/44571078.html.
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Thesis (M.S.)--University of Wisconsin--Madison, 2000.Typescript. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references (leaves 98-104).
Books on the topic "Time-lag mechanism"
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Shaughnessy, Robert. The Time Is Out of Joint. Edited by James C. Bulman. Oxford University Press, 2017. http://dx.doi.org/10.1093/oxfordhb/9780199687169.013.31.
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One of the culturally dominant means through which time is conceptualized as space, and vice versa, jet lag has increasingly become a metaphor we live by. It has particular resonances for Shakespearean performance, a phenomenon that is, by definition, perpetually out of time. Taking as a point of departure Brian Cox’s 1991 account of his experience of the National Theatre’s touring productions of King Lear and Richard III, this chapter aligns the predicament of the jet -lagged traveller, the off-form actor, and the jet-lagged, off-form travelling actor to argue that their mutual predicament offers an under-explored frame of reference for performance in general and for Shakespeare in performance in particular. It examines how mechanisms of synchrony (or entrainment) shape the actor’s work in performance and with the audience. It also examines the implications of theatrical good and bad timing, and the sometimes unexpected consequences of time getting out of joint.
Book chapters on the topic "Time-lag mechanism"
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Baranovska, Lesia V. "Group Pursuit Differential Games with Pure Time-Lag." In Contemporary Approaches and Methods in Fundamental Mathematics and Mechanics, 475–88. Cham: Springer International Publishing, 2020. http://dx.doi.org/10.1007/978-3-030-50302-4_23.
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Collier, Richard S. "Cum-Ex in Concept." In Banking on Failure, 11–38. Oxford University Press, 2020. http://dx.doi.org/10.1093/oso/9780198859673.003.0002.
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This chapter examines the essential features of the cum-ex trade and outlines the ‘base template’ which was the foundation for the later refinement and expansion of the trade. The chapter begins by dealing separately with a number of the individual components that are relevant to the cum-ex trade: it explains the concept of dividend arbitrage, the workings of withholding taxes and tax credits, the distinction between cum-dividend and ex-dividend share sales, the idea of a settlement time lag, the workings of the dividend adjustment mechanism, and the concept of short selling. The discussion then explains how these individual components were assembled and synchronized in order to deliver the basic cum-ex trade.
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Mkrttchian, Vardan, Alexander Bershadsky, Alexey Finogeev, Artiom Berezin, and Irina Potapova. "Digital Model of Bench-Marking for Development of Competitive Advantage." In User Innovation and the Entrepreneurship Phenomenon in the Digital Economy, 288–303. IGI Global, 2018. http://dx.doi.org/10.4018/978-1-5225-2826-5.ch014.
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The chapter deals with the problems of digital modeling and the study of the interaction of the companies competing within the framework of the bench-marking process for definition, understanding and working out the strategy of effective functioning and increasing competitiveness. The companies are considered in the organizational field, representing iterative aggregate system of a big order with a nonlinear feedback where the order is defined by the number of differential equations. The system is described by coupled Van Der Pol differential equations with random right parts and a time lag. The model is built on the example of the market interaction of the two largest retailer networks. The developed model shows the mechanism of competition of the companies' pairs which are suggested to be investigated within the framework of the bench-marking concept.
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Mkrttchian, Vardan, Andrey Berezin, Artyom Andreevich Berezin, Svetlana Veretekhina, Alexander Bershadsky, and Irina Potapova. "Model of Benchmarking for Development of Firm's Competitive Advantage to Improve Economic Growth in Cities." In Advances in Electronic Government, Digital Divide, and Regional Development, 118–40. IGI Global, 2019. http://dx.doi.org/10.4018/978-1-5225-5448-6.ch006.
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The chapter deals with the problems of digital modeling and the study of the interaction of the companies competing within the framework of bench-marking process for working out the strategy of effective increasing competitiveness that is advantageous for the urban economic growth. The companies are considered in the organizational field, representing iterative aggregate system of a big order with a nonlinear feedback where the order is defined by the number of differential equations. The system is described by coupled Van Der Pol differential equations with random right parts and a time lag. The model is built on the example of the market interaction of the two largest retailer networks. The developed model shows the mechanism of competition of the companies' pairs which are suggested to be investigated within the framework of the bench-marking concept.
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Ludwig, Horst, and Wilhelm Scigalla. "Pressure- and Temperature-Induced Inactivation of Microorganisms." In High Pressure Effects in Molecular Biophysics and Enzymology. Oxford University Press, 1996. http://dx.doi.org/10.1093/oso/9780195097221.003.0025.
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Bacteria are unstable when the temperature or pressure is sufficiently high. Their inactivation by pressure is the result of a complicated interplay of both temperature and pressure effects. The p-T stability diagram of bacteria is similar to that of proteins. But inactivation kinetics of bacteria indicate that the lethal event cannot be the denaturation of the most sensitive proteins in the cell. For in that case one would expect a lag time followed by a sudden inactivation when the last copy of those sensitive proteins was destroyed. On the contrary, it appears as if the kinetics is caused by a single damage mechanism. In addition, some evidence suggests that the membrane is involved. Therefore, it seems that membrane-associated proteins play a major role in the activation of bacteria. The inactivation of bacterial spores shows an even more complex T-p interrelationship. The reason is that two different processes are combined in spore inactivation: the germination of dormant spores at comparatively low pressures and the inactivation of the germinated specimens at high pressures. Thus, special procedures are needed for effective spore inactivation. Microorganisms are killed when the surrounding hydrostatic pressure is sufficiently high. This finding provides the basis for developing a physical sterilization method for drugs and food. Initial experiments in this area were carried out nearly 100 years ago (Hite, 1899), but technical shortcomings and incomplete scientific knowledge impeded their utilization at that time. Recently, the application of high pressure in food preservation and processing has garnered new interest (Hayashi 1989; Balny et al, 1992). To collect precise kinetic data for pressure-induced degermination, we constructed a device which consisted of 10 pressure vessels that could be thermostated in two groups of five each. Each vessel had an inner diameter of 1.2cm and an inner length of 12 cm. The samples were separated from the pressure medium, water, by polyethylene tubes or bags. The maximum pressure was 7 kbar. The vegetative bacteria were always freshly cultured from one single organism before each experimental run. The preparations were allowed to grow to the exponential phase and were used in experiments just before the stationary phase had been reached.
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Kandler, Anne, and Fabio Caccioli. "Networks, Homophily, and the Spread of Innovations." In The Connected Past. Oxford University Press, 2016. http://dx.doi.org/10.1093/oso/9780198748519.003.0016.
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The question of how and why innovations spread through populations has been the focus of extensive research in various scientific disciplines over recent decades. Generally, innovation diffusion is defined as the process whereby a few members of a social system initially adopt an innovation, then over time more individuals adopt until all (or most) members have adopted the new idea (e.g. Rogers 2003; Ryan and Gross 1943; Valente 1993). Anthropologists and archaeologists have argued that this process is one of the most important processes in cultural evolution (Richerson et al. 1996) and much work has been devoted to describing and analysing the temporal and spatial patterns of the spread of novel techniques and ideas from a particular source to their present distributions. Classic case studies include the spread of agricultural inventions such as hybrid corn (e.g. Griliches 1957; Ryan and Gross 1943), the spread of historic gravestone motifs in New England (Dethlefsen and Deetz 1966; Scholnick 2012), and the spread of bow and arrow technology (Bettinger and Eerkins 1999). (For a more comprehensive list see Rogers and Shoemaker (1971) who reviewed 1,500 studies of innovation diffusion.) Interestingly, the temporal diffusion dynamic in almost all case studies is characterized by an S-shaped diffusion curve describing the fraction of the population which has adopted the innovation at a certain point in time. Similarly, the spatial dynamics tend to resemble travelling wave-like patterns (see Steele 2009 for examples). The basic puzzle posed by innovation diffusion is the observed lag between an innovation’s first appearance and its general acceptance within a population (Young 2009). In other words, what are the individual-level mechanisms that give rise to the observed population-level pattern? Again, scientific fields as diverse as economics/marketing science (e.g. Bass 1969; Van den Bulte and Stremersch 2004; Young 2009), geography (e.g. Hägerstrand 1967), or social science (e.g. Henrich 2001; Steele 2009; Valente 1996; Watts 2002) offer interesting insights into this question without reaching a consensus about the general nature of individual adoption decisions. In archaeological and anthropological applications, population-level patterns inferred from the archaeological record, such as adoption curves, are often the only direct evidence about past cultural traditions (Shennan 2011).
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Baer, Tomas, and William L. Hase. "Dynamical Approaches to Unimolecular Rates." In Unimolecular Reaction Dynamics. Oxford University Press, 1996. http://dx.doi.org/10.1093/oso/9780195074949.003.0010.
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In the previous chapters theories were discussed for calculating the unimolecular rate constant as a function of energy and angular momentum. The assumption inherent in these theories is that a microcanonical ensemble is maintained during the unimolecular reaction and that every state in the energy interval E → E + dE has an equal probability of decomposing. Such theories are viewed as statistical since the unimolecular rate constant is found from a statistical counting of states in the microcanonical ensemble. A dynamical description of unimolecular decomposition is concerned with properties of individual states of the energized molecule. Of interest are the decomposition probabilities for the states as well as the rate of transitions between the states. Dynamical theories of unimolecular decomposition deal with the properties of vibrational/rotational energy levels, state preparation and intramolecular vibrational energy redistribution (IVR). Thus, the presentation in this chapter draws extensively on the previous chapters 2 and 4. Unimolecular decomposition dynamics can be treated using quantum and classical mechanics, and both perspectives are considered here. The role of nonadiabatic electronic transitions in unimolecular dynamics is also discussed. A molecule which can dissociate does not, strictly speaking, have a discrete energy spectrum. The relative motion of the product fragments is unbounded and, in this sense the motion of the unimolecular system is infinite, and hence the energy spectrum is continuous. However, it may happen that the dissociation probability of the molecule is sufficiently small that one can introduce the concept of quasi-stationary states. Such states are commonly referred to as resonances since the energy of the unimolecular fragments in the continuum is in resonance with (i.e., matches) the energy of a vibrational/rotational level of the unimolecular reactant. For unimolecular reactions there are two types of resonance states. The simplest type, a shape resonance, occurs when a molecule is temporarily trapped by a fairly high and wide potential energy barrier. The second type of resonance, called a Feshbach or compound-state resonance, occurs when energy is initially distributed between vibrational/rotational degrees of freedom of the molecule which are not strongly coupled to the fragment relative motion, so that there is a time lag for unimolecular dissociation.
Conference papers on the topic "Time-lag mechanism"
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Yining, Sui, Huang Yaning, Sun Chenhui, and Zhang Dixin. "Competitive Mechanism of FDI and Time-lag of Spillovers." In 2012 International Conference on Business Computing and Global Informatization (BCGIN). IEEE, 2012. http://dx.doi.org/10.1109/bcgin.2012.25.
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Ling-yun, He, and Liu Chuan-zhe. "Empirical Research on the Time Lag of China's Monetary Exchange Rate Transmission Mechanism." In 2006 International Conference on Management Science and Engineering. IEEE, 2006. http://dx.doi.org/10.1109/icmse.2006.314043.
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Gursul, Ismet. "A proposed mechanism for the time lag of vortex breakdown location in unsteady flows." In 38th Aerospace Sciences Meeting and Exhibit. Reston, Virigina: American Institute of Aeronautics and Astronautics, 2000. http://dx.doi.org/10.2514/6.2000-787.
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Subramani, Nandha Kumar, Mohamed Bouslama, Raphael Sommet, and Jean-Christophe Nallatamby. "Time Domain Drain Lag Measurement and TCAD-based Device Simulations of AlGaN/GaN HEMT: Investigation of Physical Mechanism." In 2019 14th European Microwave Integrated Circuits Conference (EuMIC). IEEE, 2019. http://dx.doi.org/10.23919/eumic.2019.8909549.
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Jia, Yi, and Jun Huan. "The Analysis of Arabidopsis thaliana Circadian Network Based on Non-stationary DBNs Approach with Flexible Time Lag Choosing Mechanism." In 2009 IEEE International Conference on Bioinformatics and Biomedicine (BIBM). IEEE, 2009. http://dx.doi.org/10.1109/bibm.2009.81.
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Nagayama, R., A. Hattori, I. Fuse, T. Takeshige, S. Takizawa, and A. Shibata. "PLATELET IONIZED CALCIUM MOBILIZATION (AEQUORIN METHOD) IN PATIENTS WITH PRIMARY PLATELET DYSFUNCTION." In XIth International Congress on Thrombosis and Haemostasis. Schattauer GmbH, 1987. http://dx.doi.org/10.1055/s-0038-1644571.
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Intracellular calcium level of platelets of the patients with primary platelet dysfunction (thrombasthenia, platelet cyclo-oxygenase deficiency, familial defect of A23187 induced platelet aggregation, Hermansky-Pudlak syndrome. Bernard-Soulier syndrome, each 1 case, and other 3 cases of platelet release mechanism defect of unknown etiology) were measured with the photoprotein Aequorin according to the method by Johnson et al. The peak level and the lag time to the peak were evaluated. Activation was done by 4 or more different concentrations of either thrombin (0.125-1.0μ/ml), A23187 (0.25-2.0μM), ATA2 (0.05-0.4μM) or occasionally arachidonate (0.25-100μM).In case of stimulation by thrombin, the maximum [Ca2+] level in thrombasthenia was much lower than those in normal. The lag time was prolonged in Bernard-Soulier syndrome. In case of stimulation by STA2 the maximum [Ca2+] level was very much lower in thrombasthenia and was lower in a familial defect of A23187-induced platelet aggregation and a case of platelet release mechanism defect than normals. In case of stimulation by A23187, the maximum [Ca2+] level was much lower in thrombasthenia and PCO deficiency and platelet release mechanism defect (2 cases) in which the lag time of A23187 induced platelet aggregation was also prolonged. In PCO deficiency, arachodonate less than μM produced a dose-dependent rise in intracellular calcium level and that (1-25μM) caused a rise of a consistent level although it didn't induce aggregation. Arachidonate (25-100M) caused both higher rise and aggregation. Mobilization was normal in response to STA2 and thrombin but decreased to A23187 in this deficiency.These findings suggest that [Ca2+] mobilization was deteriorated by many mechanisms such as defect of PGG2H2-and Tx-forma-tion, membranous abnormality (lack of glycoproteins) and storage pool deficiency, and further that atachidonate even at low concentration may cause mobilization without conversion to PGG2H2 or Tx.
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Khalifa, Ahmed, David Weaver, and Samir Ziada. "An Experimental Study of the Phase Lag Causing Fluidelastic Instability in Tube Bundles." In ASME 2011 Pressure Vessels and Piping Conference. ASMEDC, 2011. http://dx.doi.org/10.1115/pvp2011-57263.
Full textAbstract:
The phenomenon of fluidelastic instability forms a major limitation on the performance of tube and shell heat exchangers. It is believed that fluidelastic instability is attributed to two main mechanisms; the first is called the “Damping Mechanism”, while the second is called the “Stiffness Mechanism”. It is established in the literature that in order to model the damping controlled fluidelastic instability, a finite time delay between tube vibration and fluid response has to be introduced. Experimental investigation of the time delay between structural motion and the induced fluid forces is detailed in the present study. A parallel triangular tube array consisting of seven rows and six columns of aluminum tubes is built with a pitch ratio of 1.54. Hot-wire measurements of the interstitial flow perturbations are recorded while monitoring the tube vibrations in the lift and drag directions. Pressure transducers are installed inside the instrumented tubes to monitor the fluid forces. The phase lag between tube vibration and flow perturbation is obtained at different locations in the array. The effect of tube frequency, turbulence level, location of measurements, and mean gap velocity on the relative phase values is investigated. It is found that there are two well-defined regions of phase trends along the flow channel. It is concluded from this study that the time delay between tube vibration and downstream flow perturbation is associated with the vorticity convection downstream, while the time delay for upstream perturbations is associated with the effect of flow separation and vorticity generation which is propagated upstream from the vibrating tube.
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Im, Hong-Sik, and Ge-Cheng Zha. "Flutter Prediction of a Transonic Fan With Travelling Wave Using Fully Coupled Fluid/Structure Interaction." In ASME Turbo Expo 2013: Turbine Technical Conference and Exposition. American Society of Mechanical Engineers, 2013. http://dx.doi.org/10.1115/gt2013-94341.
Full textAbstract:
This paper uses a fully coupled fluid/structure interaction (FSI) to investigate the flutter mechanism of a modern transonic fan rotor with a forward travelling wave. To induce an initial travelling wave for the blade structure, an initial BC that can facilitate each blade to vibrate with a time lag by a given nodal diameter (ND) is implemented. Unsteady Reynolds-averaged Navier-Stokes (URANS) equations are solved with a system of structure modal equations in a fully coupled manner. The 5th order WENO scheme with a low diffusion E-CUSP Riemann solver is used for the inviscid fluxes and a 2nd order central differencing is used for the viscous terms. A half annulus sector is used for the flutter simulations with a time shifted phase lag boundary condition at the circumferential boundaries. The present FSI simulations show that the shock instability causes the flutter. When the detached normal shock moves further upstream in a direction normal to the blade chord, the interaction of the detached normal shock with tip leakage vortex creates more serious blockage to the blade passage that can introduce an aerodynamic instability to the blade structure due to the incoming flow disturbance, resulting in flutter. The flutter of the transonic fan observed in this study occurs at the 1st mode before the stall. The predicted flutter boundary agrees well with the experiment.
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Sohn, Dong Kee, and Joon Sik Lee. "The Effect of Bulk Flow Pulsations on Film Cooling From Two Rows of Holes." In ASME 1997 International Gas Turbine and Aeroengine Congress and Exhibition. American Society of Mechanical Engineers, 1997. http://dx.doi.org/10.1115/97-gt-129.
Full textAbstract:
Effect of bulk flow pulsations on film cooling from two rows of holes with inline and staggered arrangements is experimentally investigated. As a baseline study, a single row injection is also tested. Two-row injection is important because the phase lag between the two rows may cause changes in the film coolant coverage. Potential flow pulsations are generated by the rotating shutter mechanism attached downstream of the test section. Free-stream Strouhal number based on the boundary layer thickness is in the range of 0.033–0.33, and the amplitude of the phase-averaged freestream velocity due to static pressure variation about 10–20% Both the time-averaged and phase-averaged temperature distributions in the cross-sectional plane of the boundary layer are presented for four different pulsation frequencies of 0, 4, 20 and 40 Hz. Film cooling effectiveness is evaluated from the adiabatic wall temperature distributions, with time-averaged temperature measurements showing rapid diffusion of the injectant due to the free-stream pulsations. Effect of the phase lag between two rows is evidenced from the phase-averaged measurements, particularly in the case of staggered hole arrangement. All film cooling effectiveness distributions are reduced compared to no-pulsation case. Effect of pulsations appears dominantly in the case of the two-row staggered arrangement which shows more than 35% reduction in the film cooling effectiveness.
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Zhou, Jianhua, J. K. Chen, and Yuwen Zhang. "Nonclassical Heat Transfer Models for Laser-Induced Thermal Damage in Biological Tissues." In ASME 2011 International Mechanical Engineering Congress and Exposition. ASMEDC, 2011. http://dx.doi.org/10.1115/imece2011-62018.
Full textAbstract:
To ensure personal safety and improve treatment efficiency in laser medical applications, one of the most important issues is to understand and accurately assess laser-induced thermal damage to biological tissues. Biological tissues generally consist of nonhomogeneous inner structures, in which heat flux equilibrates to the imposed temperature gradient via a thermal relaxation mechanism which cannot be explained by the traditional parabolic heat conduction model based on Fourier’s law. In this article, two non-Fourier heat conduction models, hyperbolic thermal wave model and dual-phase-lag (DPL) model, are formulated to describe the heat transfer in living biological tissues with blood perfusion and metabolic heat generation. It is shown that the non-Fourier bioheat conduction models could predict significantly different temperature and thermal damage in tissues from the traditional parabolic model. It is also found that the DPL bioheat conduction equations can be reduced to the Fourier heat conduction equations only if both phase lag times of the temperature gradient (τT) and the heat flux (τq) are zero. Effects of laser parameters and blood perfusion on the thermal damage simulated in tissues are also studied. The result shows that the overall effects of the blood flow on the thermal response and damage are similar to those of the time delay τT. The two-dimensional numerical results indicate that for a local heating with the heated spot being smaller than the tissue bulk, the variations of the non-uniform distributions of temperature suggest that the multi-dimensional effects of thermal wave and diffusion not be negligible.