Period Of Exponential Increase Research Articles

Width effect and local transient heat transfer characteristics for helium gas flowing over a twisted plate

Forced convection transient heat transfer for helium gas at various periods of exponential increase of heat input to a short twisted plate with various helix angles was experimentally studied. Twisted plates were made of platinum plate with a thickness of 0.1 mm and width of 2 and 4 mm. The heat generation rates of the heater was raised with exponential function, , where t is time, and τ is period of heat generation rate. The transient heat transfer experimental data were measured for the periods ranged from 80 ms to 17 s and at a gas temperature of 303 K under 500 kPa. The flow velocities ranged from 4 to 10 m/s. In the experiments, the twisted plates with different width were tested. The local mean heat transfer coefficients have been tested as well. An enhancement in the heat transfer coefficient for the twisted plate with different width was clarified. And also, the heat transfer coefficients for the first half pitch are 24% higher than that for the total length of the same twisted plate.

A reply to Etzkowitz’ comments to Leydesdorff and Martin (2010): technology transfer and the end of the Bayh–Dole effect

Three periods can be distinguished in university patenting at the U.S. Patent and Trade Office (USPTO) since the Bayh---Dole Act of 1980: (1) a first period of exponential increase in university patenting till 1995 (filing date) or 1999 (issuing date); (2) a period of relative decline since 1999; and (3) in most recent years--since 2008--a linear increase in university patenting. We argue that this last period is driven by specific non-US universities (e.g., Tokyo University and Chinese University) patenting increasingly in the USA as the most competitive market for high-tech patents.

Formation and development of the Black Sea-Caspian kilka Clupeonella cultriventris (Clupeidae) in the Rybinsk reservoir

We studied the state and development of the population of the Black Sea-Caspian kilka Clupeonella cultriventris in the Rybinsk reservoir from 1994 to 2010. The population dynamics, the rate of growth of the kilka, as well as its food relationships with other fish species of the pelagial community, were analyzed. It was found that the period of exponential increase in the numbers was replaced by the period of interannual fluctuations. With the development of the population, tendencies for a decrease in the rate of growth of the kilka and aggravation of its food relationships with other species are revealed, which is determined by changes in the structure of pelagic aggregations of fish. One of the most significant environmental factors determining dynamics of the numbers and state of the kilka population in the northernmost part of its modern range is water temperature.

Dynamic adjustment of Scalable TCP congestion control parameters

This paper investigates two common problems associated with Scalable TCP: (1) that in long-delay connections, Scalable TCP is slow in achieving full utilization of the bandwidth; and (2) that competing flows with different round-trip times may consume vastly different shares of the bandwidth. Through a mathematical analysis of the issues behind these behaviors, expressions are derived for the evolution of the congestion window ( W) over time. In particular, we identify two regimes in the congestion avoidance phase: a period of exponential increase that lasts as long as the buffer is empty, followed by a linear increase when the buffer is not empty. Accordingly, we also present expressions for the throughput after packet loss begins to occur due to buffer overflow and/or random link failure. We observe that the throughput is inversely proportional to the round-trip time (RTT) of the connection, which leads to the high unfairness of Scalable TCP for multiple connections with different round-trip times. We then derive a formula that permits dynamical adjustment of the congestion window increase and decrease parameters based on the measured round-trip time of the connections. Finally, a number of network simulations demonstrate that the modified algorithm achieves a better allocation of throughput in scenarios with a variety of connections.

Density‐dependent parameters and demographic equilibrium in open populations

Populations near their equilibrium are expected to show density‐dependence through a negative feedback on at least one demographic parameter, e.g. survival and/or productivity. Nevertheless, it is not always clear which vital rate is affected the most, and even less whether this dependence holds in open populations in which immigration and emigration are also important. We assessed the relative importance of population density in the variation of local survival, recruitment, proportion of transients (emigrants) and productivity through the analysis of detailed life‐histories of 4286 seabirds from a colony that reached an apparent demographic equilibrium after a period of exponential increase. We provide evidence that the role of population density and resource availability changes according to the demographic parameter considered. Estimates indicated that transients increased from 5% to 20% over the study period, suggesting an average turnover of about 1400 individuals per year. The parameters most influenced by population density alone were local survival and probability of transience. Recruitment was negatively associated with population density during the increasing phase but unexpected high values were also recorded at high population levels. These high values were explained by a combination of population size and food availability. Mean productivity varied with food availability, independently from population variations. The population density alone explained up to a third of the yearly variation of the vital rates considered, suggesting that open populations are equally influenced by stochastic and density‐independent events (such as environmental perturbations) than by intrinsic (i.e. density‐dependent) factors.

1811 増加熱入力による気流中の水平平板発熱体過渡熱伝達(G06-2 伝熱(2),G06 熱工学)

Forced convection transient heat transfer for helium gas at various periods of exponential increase in heat input to a horizontal plate (ribbon) was experimentally and theoretically studied. In the experimental studies, the authors measured heat flux, surface temperature, and transient heat transfer coefficients for forced convection flow of helium gas over a horizontal plate. The gas flow velocities ranged from 4 to 10m/s, the gas temperatures ranged from 313 to 353K, and the periods of heat generation rate, τ, ranged from 46ms to 17s. Empirical correlations for quasi-steady-state heat transfer and transient heat transfer were obtained based on the experimental data. In the theoretical study, transient heat transfer was numerically solved based on a turbulent flow model. It was obtained that the surface superheat and heat flux increase exponentially as the heat generation rate increases with the exponential function.

Dynamics of viremia in early hepatitis C virus infection

It is important to characterize viral dynamics in early hepatitis C virus (HCV) infection to further our understanding of viral pathogenesis and the potential for secondary transmission in acute infection through blood transfusion or other routes. Serial units given by 77 source plasma donors who had evolved from HCV RNA-negative to HCV RNA-positive by nucleic acid amplification technology (NAT) screening with 512-unit pool-NAT or were followed from RNA detection to antibody conversion were tested by individual NAT and quantitative RNA assays. During the ramp-up phase when exponential growth occurs, HCV viral load doubled every 10.8 hours (95% confidence interval [CI], 9.9-12.0). Intermittent viremia was observed before the ramp-up phase in 37 of 50 panels with the earliest detectable viremic bleed occurring 63 days before the estimated onset of ramp-up. The plateau phase or high-titer viremic period that occurs between ramp-up and seroconversion was estimated to last 56.3 days (95% CI, 44.8-67.8). Intermittent low-level HCV viremia can occur as much as 2 months before the periods of exponential increase in viral load and the high-titer plateau-phase viremia that usually precede seroconversion. Animal inoculation studies are in progress to evaluate if transfusion of low-level viremic plasma can transmit HCV infection.

Characteristics of the population build‐up of the Russian wheat aphid Diuraphis noxia and the effect on wheat yield in the eastern Orange Free State

Summary Diuraphis noxia infestations were monitored in early winter and winter wheat during 1983–1985. The aphid population increase was logarithmic in all three years and on both cultivars 100 % infestation levels were recorded. The period of exponential increase in both percentage infestation and in the number of D. noxia per stem took place when the plants had reached the stem elongation stage. The mean number recorded at peak population levels was 150–160 aphids per stem. During the period of plant senescence numbers dropped rapidly. Large reductions in yield were recorded on all infested plants. Single‐plant data showed that yield reductions in the early winter cv. Betta were related to the duration of infestation. Relative to sprayed controls, reduction in kernel mass ranged from 25–80% and in 1000‐kernel mass from 15–45%. However, the yield reductions of the faster‐growing cv. Flamink, appeared to be dependent on the number of aphids per plant during the later growth stages and not the duration of infestation.

Slow secondary fluorescence kinetics associated with the onset of photosynthetic carbon assimilation in intact isolated chloroplasts

Experiments with carefully isolated, largely intact chloroplasts, capable of fast rates of CO 2 -dependent O 2 evolution, show that the fall in chlorophyll a fluorescence (from the early maxima reached immediately after illumination) is interrupted by a ‘shoulder’ which is associated with the exponential increase in the rate of O 2 evolution. The length of this induction period was increased by storage, by decreased temperature, by increased orthophosphate concentration in the assay medium or by the presence of D, L-glyceraldehyde. It could also be shortened by the addition of 3-phosphoglycerate or dihydroxyacetonephosphate. In each treatment the shoulder in fluorescence shifted so that the association with the period of exponential increase was maintained. When illumination was re-started after a short dark interval, induction was minimal and no shoulder could be discerned, but both the lag in the onset of O 2 evolution and the shoulder were restored when the chloroplasts were resuspended in fresh assay medium during the period of darkness. The relation between chlorophyll a fluorescence and the onset of photosynthetic carbon assimilation is discussed.

Publication in American Geology to 1850

Activity in American earth science increased at an exponential rate from 1780 through 1850, on the basis of the number of geologic publications recorded in the Bibliography of American-Published Geology: 1669 to 1850. Subdisciplines of earth science, such as vertebrate paleontology, mineralogy, and field mapping, grew in a regular succession of stages. At first, publication was sporadic because natural phenomena were observed but not understood in a larger framework. A key work, such as a new theory or classification scheme that succeeded in unifying isolated observations, stimulated a period of exponential increase in activity as many researchers were shown a clear direction to pursue. In some fields, the publication rate eventually slowed down and then reached zero as the objectives of a research tradition were met or a new competing program was more successful. The overall exponential increase of activity in geology was the net result of several subdisciplines being in various stages of growth.

Ribonuclease activity in the developing seeds of normal and opaque-2 maize.

During development, the ribonuclease activity of maize endo sperm homozygous for the opaque-2 gene increased earlier and, after a longer period of exponential increase, was much higher finally than in normal endosperm. The maximum difference was about sixfold and occurred 22 to 25 days after pollination. Heterozygotes on day 23 did not show a comparable in crease in endosperm activity. No differ ence in the activity ratio (pH 6.0: pH 5.2) was found between normal and opaque-2 endosperm, indicating that the increase in activity in opaque-2 was due solely to an increase in ribo nuclease A. The ribonuclease activity of opaque-2 embryos increased more rapidly than that of normal embryos, but the final activity was the same in each case.

Multiplication of a myxovirus (SV5) with minimal cytopathic effects and without interference

SV5 virus, a simian myxovirus, multiplies to high titer in rhesus monkey kidney cells, but causes only minimal cytopathic effects. It forms plaques with high efficiency, the plaques consisting of intact cells with diminished neutral red staining.After inoculation of SV5 virus at a multiplicity of 40–70 PFU/cell, the latent period was 6–7 hours, and the doubling time during the period of exponential increase in infective virus was approximately 50 minutes. In 24 hours, yields of 500–1500 PFU/cell were obtained. Cells continued to produce high yields of infective virus for periods up to 30 days.Inoculation of SV5 virus at high multiplicity did not result in autointerference or incomplete virus formation. Multiplication of SV5 virus in monkey kidney cells for 48 hours did not interfere with subsequent infection and plaque formation by a second virus, and did not significantly reduce the yield of a superinfecting virus.