Correlation of spray dropsize distribution and injector variables Interim report

Correlation of spray drop size distribution and injector variable

Purpura Hemorrhagica in Pertussis

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Nonlinear response of a blade-stiffened graphite-epoxy panel with a discontinuous stiffener: Work in progress

The problem of calculating detailed stress distributions around discontinuities in buckled, composite structural components for use with the various analytical failure prediction techniques has not been thoroughly explored. The purpose here is the application of computational methods to the detailed stress analysis problem which is the focus of this session of the workshop. One approach to uncovering the difficulties of this type of analysis and to providing specific directions for future research in this area is a direct attack on the problem using currently available analysis tools. A candidate problem has been selected and experiences from calculating its structural response are described

A rotor-mounted digital instrumentation system for helicopter blade flight research measurements

A rotor mounted flight instrumentation system developed for helicopter rotor blade research is described. The system utilizes high speed digital techniques to acquire research data from miniature pressure transducers on advanced rotor airfoils which are flight tested on an AH-1G helicopter. The system employs microelectronic pulse code modulation (PCM) multiplexer digitizer stations located remotely on the blade and in a hub mounted metal canister. As many as 25 sensors can be remotely digitized by a 2.5 mm thick electronics package mounted on the blade near the tip to reduce blade wiring. The electronics contained in the canister digitizes up to 16 sensors, formats these data with serial PCM data from the remote stations, and transmits the data from the canister which is above the plane of the rotor. Data are transmitted over an RF link to the ground for real time monitoring and to the helicopter fuselage for tape recording. The complete system is powered by batteries located in the canister and requires no slip rings on the rotor shaft

A Conversation Among Deans on Results: Legal Education, Institutional Change, and a Decade of Gender Studies

On March 10, 2006, the Harvard Journal of Law & Gender, cosponsoring with the Harvard Civil Rights-Civil Liberties Law Review and the Harvard Law Review, hosted a conference, Results: Legal Education, Institutional Change, and a Decade of Gender Studies, to address the number of student experience studies that detail women\u27s lower performance in and dissatisfaction with law school. Rather than advocate for a particular set of responses to the different experiences of men and women in legal education, this conference sought to foster a discussion about the institutional challenges these patterns highlight. As one means of accomplishing this end, law school deans from across the country spoke about their strategies to change legal education. Edward Rubin, dean of Vanderbilt Law School, discussed how law school still acts as a rite of passage that is more suited to an era when the public sphere was male-dominated, and suggested reforms in legal curriculum in light of changes in the legal profession. W. H. Knight, dean of the University of Washington School of Law, concentrated on how law school culture might change as to become more rewarding for students and more inclusive of students from diverse backgrounds. Katherine Bartlett, dean of Duke Law School, spoke about the role of technology in infusing the context in which law operates in the study of law, as well as the Duke Blueprint, a mission statement that helps students (and faculty) examine the motives and values they will bring to becoming a lawyer

Mountain Pine Beetle Outbreaks in the Rocky Mountains: Regulators of Primary Productivity?

We consider the hypothesis that mountain pine beetles function as cybernetic regulators of primary productivity in ecosystems of lodgepole pine forest through their selective killing of dominant trees and the subsequent redistribution of resources. Following a recent major beetle outbreak in Yellowstone and Grand Teton national parks, surviving trees did grow significantly faster (P \u3c .1); wood production was redistributed among canopy, subcanopy, and understory trees; and annual wood production per hectare usually returned to pre-attack levels or exceeded them within 10-15 yr. However, reconstructions of annual wood production over the last 70-80 yr indicate that the beetle outbreak did not reduce the variation in productivity; rather, the beetles introduced more variation than would have existed in their absence. Hence, our results do not support the hypothesis that the beetles function as cybernetic regulators (in the strict sense). Nevertheless, the beetle-pine system that we studied shows great resilience, and the effects of beetles on primary productivity do not appear to be as severe as conventional wisdom maintains. Annual wood production per hectare returned quickly to previous levels in the stands we studied, and associated ecological changes can be considered generally benign or even beneficial

Water and Nutrient Outflow From Contrasting Lodgepole Pine Forests in Wyoming

Factors affecting water and nutrient outflow beyond the rooting zone were studied during a 3—yr period, using data from eight contrasting stands of lodgepole pine (Pinus contorta ssp. latifolia) forest in southeastern Wyoming and the output of a hydrologic simulation model (H2OTRANS) based on tree physiology. Nutrient outflow during a specific time period was estimated by multiplying simulated water outflow times element concentrations in the soil solution, the latter determined from samples collected periodically near the bottom of the rooting zone. Estimates of actual evapotranspiration (ET) for the period from early spring to late fall ranged from 21 to 53 cm, which was 33—95% (x = 73%) of total annual precipitation. For all stands and years, transpiration accounted for 50—61% of ET, and 9—44% of the transpiration occurred during the spring drainage period (vernal transpiration, VT). Estimated VT and outflow varied considerably among the stands, with VT accounting for 4—20% of the snow water. Outflow occurred only during the snow melt period and accounted for 0—80% of the snow water. Snow water equivalent varied annually by 300% or more. Nutrient outflow from the different stands also varied greatly. Ratios between simulated annual outflow and atmospheric inputs (bulk precipitation) were consistently \u3e1.0 for Ca, Na, and Mg; were consistently \u3c1.0 for N; and ranged from 0.3 to 2.0 for P and from 0.2 to 3.3 for K. Much of the variability in water and nutrient outflow can be attributed to the degree of biotic control, with water outflow affected by a different combination of factors than nutrient outflow. H2OTRANS was used to simulate the effects on outflow of different snow water equivalents and different total leaf areas. One result of the simulations was that nitrogen appears to be retained even at the highest levels of water outflow. Another was that increases in water outflow following reduction in leaf area were proportional to the leaf area removed. The results indicate that stands differing in site or habitat type experience different rates of water and element losses at different times during the snow melt season, and contribute differentially to streamwater quality and hydrograph shape. Factors affecting outflow are discussed in the context of successional trends, common perturbations including timber harvest, and hypotheses pertaining to nutrient conservation in terrestrial ecosystems. Nutrient retention in the snow—dominated lodgepole pine ecosystem appears to be primarily dependent on evergreen leaf area, duration of the VT period, and high carbon/nutrient ratios of the forest floor. Net losses of limiting nutrients probably occur primarily in pulses after abiotic perturbations such as fire

Impacts of Grazing on Watersheds: A State of Knowledge.

36 pgLivestock grazing affects watershed hydrologic properties by removing protective plant cover and by trampling. Reductions in the vegetation cover may: (a) increase the impact of raindrops, (b) decrease soil organic matter and soil aggregates, (c) increase surface crusts, (d) decrease infiltration rates, and/or increase erosion. Resultant impacts may include increased overland flow, reduced soil water content, and increased erosion. Bacteria and/or nutrients as potential pollutants from livestock grazing do not appear to be a problem on areas not included on riparian zones. Existing studies show no hydrologic advantage to grazing a watershed lightly rather than moderately. Some studies show no difference in soil loss, infiltration capacity, or soil bulk density between light. moderate, or ungrazed pastures. Little information supports claims for specialized grazing systems. To evaluate hydrologic impacts adequately, additional studies, both intensive and extensive, should be conducted