Plants diffusion

Unlike C3 or C4 land plants, diffusion of CO2 limits photosynthesis in aquatic plants. Consequently, algae have adapted a mechanism that allows them to actively transport or pump either CO2 or HCO3 across their membrane, thereby accumulating DIC in the cell (Lucas and Berry, 1985). Although carbon fixation is through RuBP carboxylase,... 

Heilman M. A. and Carlton R. G. (2001) Methane oxidation associated with submersed vascular macrophytes and its impact on plant diffusive mathane flux. Biogeochemistry 52, 207-224. 

CAM plants use the same chemistry but package it differently. Specifically, they lack the Kranz anatomy that is the defining characteristic of the C4 plants. Kranz is the German word for wreath and refers to the appearance—in a cross-sectioned leaf—of the cells which sheath the vascular bundles in C4 plants. CAM stands for Crassulacean Acid Metabolism. There is no such thing as crassulacean acid. The name instead refers to the initial discovery of this pathway of carbon fixation, in which oxaloacetic, malic, and pyruvic acids play key roles, in plants from the family Crassulaceae. cam plants open their stomata, take in CO2, and produce malate at night. Temperatures and, consequently, water losses are lower. During the day, the stomata are closed and the malate is processed as in the bundle-sheath cells of C4 plants. Diffusive losses of CO2 are, however, greater than those in C4 plants. 

The eggs hatch in spring imder suitable temperature and moisture conditions and additional host plant diffusates. Without host plant diffusate, J2s do not hatch in the soil for 20 years. Therefore, the substances that stimulate the hatching are considered to be effectively utilized for controlling J2s in the farm field, since the hatched J2s in the absence of host plant are to be starved. In view of this, we have searched for hatching stimulators produced by the host plants of cyst nematodes, aiming at utilizing them for potential available nematicides. 

C12H20O4. M.p. 165°C. A plant growth hormone, which is produced in damaged plant tissue, and on diffusing into adjacent intact tissue cells stimulates them to divide. Traumatic acid has been isolated from the pods of green beans. 

A new acoustic emission system (AEBIL Acoustic Emission Binary Localizer) meeting the requirements for continuous on-line structural surveillance of critical conponents of operating plants Is described in the paper. The system is specifically designed to identify and locate structurally significant, spatially concentrated, AE sources in the presence of a high rate of spatially diffuse AE events. The system performance and reliability has been extensively demonstrated in In-plant applications. 

R. L. Earrar, Jr., and E. J. Barber, Some Considerations in the Handling of Fluorine and the Chlorine Fluorides, report K/ET-252, Oak Ridge Gaseous Diffusion Plant, Oak Ridge, Term., 1979. 

To convert naturally occurring uranium oxide, yellow cake or U Og, to the gaseous UF, hydrofluoric acid is first used to convert the U Og to UF. Further fluorination using fluorine (generated from more HF) is employed to convert the UF to UF. The UF is then processed at gaseous diffusion enrichment plants. 

Different combinations of stable xenon isotopes have been sealed into each of the fuel elements in fission reactors as tags so that should one of the elements later develop a leak, it could be identified by analyzing the xenon isotope pattern in the reactor s cover gas (4). Historically, the sensitive helium mass spectrometer devices for leak detection were developed as a cmcial part of building the gas-diffusion plant for uranium isotope separation at Oak Ridge, Tennessee (129), and heHum leak detection equipment is stiU an essential tool ia auclear technology (see Diffusion separation methods). 

The resulting overall energy balance for the plant at nominal load conditions is shown in Table 3. The primary combustor operates at 760 kPa (7.5 atm) pressure the equivalence ratio is 0.9 the heat loss is about 3.5%. The channel operates in the subsonic mode, in a peak magnetic field of 6 T. AH critical electrical and gas dynamic operating parameters of the channel are within prescribed constraints the magnetic field and electrical loading are tailored to limit the maximum axial electrical field to 2 kV/m, the transverse current density to 0.9 A/cm , and the Hall parameter to 4. The diffuser pressure recovery factor is 0.6. 

Heat Recovery and Seed Recovery System. Although much technology developed for conventional steam plants is appHcable to heat recovery and seed recovery (HRSR) design, the HRSRhas several differences arising from MHD-specific requirements (135,136). First, the MHD diffuser, which has no counterpart ia a conventional steam plant, is iacluded as part of the steam generation system. The diffuser experiences high 30 50 W/cm heat transfer rates. Thus, it is necessary to allow for thermal expansion of the order of 10 cm (137) ia both the horizontal and vertical directions at the connection between the diffuser and the radiant furnace section of the HRSR. 

Uranium oxide [1344-57-6] from mills is converted into uranium hexafluoride [7783-81-5] FJF, for use in gaseous diffusion isotope separation plants (see Diffusion separation methods). The wastes from these operations are only slightly radioactive. Both uranium-235 and uranium-238 have long half-Hves, 7.08 x 10 and 4.46 x 10 yr, respectively. Uranium enriched to around 3 wt % is shipped to a reactor fuel fabrication plant (see Nuclear REACTORS, NUCLEAR FUEL reserves). There conversion to uranium dioxide is foUowed by peUet formation, sintering, and placement in tubes to form fuel rods. The rods are put in bundles to form fuel assembHes. Despite active recycling (qv), some low activity wastes are produced. 

Data on New Gaseous Diffusion Plants, U.S. DOE Oak Ridge Operations Office, ORO-685,1972. 

For aeration, diffused-air or mechanical units are used. Air diffusers are commonly used ia North America, but some mechanical aeration units are iastalled ia plants with capacities >3, 800 /d (10 gal/d). Aeration transfers oxygen to the sewage and maintains aerobic conditions, mixes sewage and floe, and keeps the floe ia suspension. 

Early models used a value for that remained constant throughout the day. However, measurements show that the deposition velocity increases during the day as surface heating increases atmospheric turbulence and hence diffusion, and plant stomatal activity increases (50—52). More recent models take this variation of into account. In one approach, the first step is to estimate the upper limit for in terms of the transport processes alone. This value is then modified to account for surface interaction, because the earth s surface is not a perfect sink for all pollutants. This method has led to what is referred to as the resistance model (52,53) that represents as the analogue of an electrical conductance... 

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