The vertical machining center (VMC) Is the most widely consumed machine tool platform In America. It goes back to our roots with the production in 1938 of the legendary Bridgeport three-axis manual ...knee mill. As revolutionary as that was for American manufacturing, the configuration's limitations became obvious over time. The manufacturer and resourceful customers created all sorts of accessories for Its table-sine plates, dividing heads and such-to access and machine more sides of the workplace than just the top. By definition, the VMC is the single most inefficient machine tool in the shop and yet, we love it qualitatively. Upon a sound structure, scrutinize additional components, such as spindles, the coolant system and chip conveying mechanism.
Unified Analysis of Thickening Baskin, Don E; Suidan, Makram T
Journal of environmental engineering (New York, N.Y.),
02/1985, Volume:
111, Issue:
1
Journal Article
Peer reviewed
Zone settling data can generally be linearized with solids concentration when the logarithm of the settling velocity is plotted as a function of either the concentration or the logarithm of the ...concentration. The resulting mathematical expressions were used to develop two generalized dimensionless solutions that describe the steady-state performance of thickeners. Graphical solutions of these models were also developed. These solutions could be used for controlling the performance of a thickener operating under transient conditions.
Great Salt Lake (Utah, USA) is one of the world's largest hypersaline lakes, supporting many of the western U.S.'s migratory waterbirds. This unique ecosystem is threatened, but it and other large ...hypersaline lakes are not well understood. The ecosystem consists of two weakly linked food webs: one phytoplankton-based, the other organic particle/benthic algae-based.
Seventeen years of data on the phytoplankton-based food web are presented: abundances of nutrients (N and P), phytoplankton (Chlorophyta, Bacillariophyta, Cyanophyta), brine shrimp (
Artemia franciscana
), corixids (
Trichocorixa verticalis
), and Eared Grebes (
Podiceps nigricollis
). Abundances of less common species, as well as brine fly larvae (
Ephydra cinerea
and
hians
) from the organic particle/benthic algae-based food web are also presented. Abiotic parameters were monitored: lake elevation, temperature, salinity, PAR, light penetration, and DO. We use these data to test hypotheses about the phytoplankton-based food web and its weak linkage with the organic particle/benthic algae-based food web via structural equation modeling.
Counter to common perceptions, the phytoplankton-based food web is not limited by high salinity, but principally through phytoplankton production, which is limited by N and grazing by brine shrimp. Annual N abundance is highly variable and depends on lake volume, complex mixing given thermo- and chemo-clines, and recycling by brine shrimp. Brine shrimp are food-limited, and predation by corixids and Eared Grebes does not depress their numbers. Eared Grebe numbers appear to be limited by brine shrimp abundance. Finally, there is little interaction of brine fly larvae with brine shrimp through competition, or with corixids or grebes through predation, indicating that the lake's two food webs are weakly connected.
Results are used to examine some general concepts regarding food web structure and dynamics, as well as the lake's future given expected anthropogenic impacts.
Full text
Available for:
FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SBCE, SBMB, UL, UM, UPUK
Increasing the resiliency of High Frequency radar measurements has been a priority within the community for the past several years. One method to increase resiliency is through the use of a bistatic ...radar configuration, which is unique to the SeaSonde HF radar. This is achieved by separating the transmit and receive stations and then linking them through the Global Positioning System (GPS) reference time signal. A study was undertaken to determine the impact of bistatic data on the surface current measurements of the Mid Atlantic Bight. Simulation software was used to model different permutations of transmit and receive stations to determine if there was an optimal configuration. The software modeled the Geometric Dilution of Statistical Accuracy (GDOSA) of the HF radar coverage area. GDOSA describes regions where combination from radials to totals is of high accuracy because the crossing angle between measurements from two different radars is orthogonal. The converse to this are regions where the total vector measurement are of low accuracy because the measurements from two different radars are nearly parallel. The scenarios tested included the bistatic measurements from the adjacent two, three and four stations on either side of a receive station. The simulation was applied to the 5, 13 and 25 MHz networks that are operated as part of the Mid Atlantic Regional Association Coastal Ocean Observing System (MARACOOS). We also simulated radars being offline to determine if any were more critical than others. Initial findings indicate that the area of highest data quality can be increased by a factor of five when the network is fully bistatic. The use of three or four adjacent radars did not increase the coverage compared to the adjacent two radars. The results of the site outage tests indicated that the loss of certain sites could reduce the coverage of the network by as much as 55%. The results found here have implications for the approximately 300 High Frequency radars that are in operation around the globe. With the addition of a hardware and software to make the network bistatic the coverage area with the highest accuracy can be increased by a dramatic amount.
PDF
