Investigation of Aerodynamic and Icing Characteristics of Recessed Fuel-Vent Configurations

An investigation has been conducted in the NACA Cleveland icing research tunnel to determine the aerodynamic and icing characteristics of several recessed fuel-vent configurations. The vents were investigated aerodynamically to obtain vent-tube pressures and pressure distributions on the ramp surface as functions of tunnel-air velocity and angle of attack. Icing investigations were made to determine the vent-tube pressure losses for several icing conditions at tunnel-air velocities ranging from 220 to 440 feet per second. In general, under nonicing conditions, the configurations with diverging ramp walls maintained, vent-tube pressures greater than the required marginal value of 2 inches of water positive pressure differential between the fuel cell and the compartment containing the fuel cell for a range of angles of attack from 0 to 14deg at a tunnel-air velocity of approximately 240 feet per second. A configuration haying divergIng ramp sldewalls, a 7deg ramp angle; and vent tubes manifold,ed to a common plenum chamber opening through a slot In the ramp floor gave the greatest vent-tube pressures for all the configurations investigated. The use of the plenum chamber resulted in uniform pressures in all vent tubes. In a cloud-icing condition, roughness caused by ice formations on the airfoil surface ahead of the vent ramp, rather than icing of the vent configuration, caused a rapid loss in vent-tube pressures during the first few minutes of an icing period. Only the configuration having diverging ramp sidewalls, a 7 ramp angle, and a common plenum chamber maintained the required vent-tube pressures throughout a 60-minute icing period, although the ice formations on this configuration were more severe than those observed for the other configurations. No complete closure of vent-tube openings occurred for the configurations investigated. A simulated freezing-rain condition caused a greater and more rapid vent-tube pressure loss than was observed for a cloud-icing condition

Adjusting farm production in Cheshire County, N.H., to market demands, Bulletin, no. 217

The Bulletin is a publication of the New Hampshire Agricultural Experiment Station, College of Life Sciences and Agriculture, University of New Hampshire, Durham, New Hampshire

Penetration In Granite By Jets From Shaped-charge Liners Of Six Materials

A new application of theory for three-dimensional collapse of conical liners shows why the two-dimensional analysis may offer a good approximation. Shaped-charge design parameters and rock target properties were investigated to determine their effects on penetration and breakage. Several metals, liner thicknesses, cone angles and standoff ranges for each were investigated. Effective standoff is greater for aluminum than more dense metals. Jets from the 60° monel, brass and steel liners gave the deepest penetration in granite. Jets from copper and brass liners gave equal penetration for 42° apex angles. Liners containing zinc produced small slugs or none at all. The holes in the granite were uniform and approximated right circular cones. Jet penetration velocities into granite varied from a maximum of 10,000 m/sec to a minimum of 2000 m/sec for the most effective metal jet. © 1973

The Emerging Epigenetic Landscape in Melanoma

Melanoma is the deadliest form of skin cancer. The disease is driven by molecular alterations in oncogenic signaling pathways, such as mitogen‐activated protein kinase (MAPK) and phosphatidylinositol 3‐kinase (PI3K). Activating mutations in oncogenes, such as BRAF and NRAS, and inactivating mutations in tumor suppressors genes, such as PTEN, promote this disease by altering cellular processes involved in growth, survival, and migration. Therapies targeting critical nodes in these pathways have demonstrated efficacy in clinical trials, but their therapeutic potential has been limited by the rapid onset of drug resistance. Durable therapeutic responses have also been observed in patients receiving immunotherapy. However, this activity appears to be confined to a subset of patients, and combinations with targeted therapies have raised safety concerns. Accumulating evidence strongly suggests that the pathogenesis of melanoma is also shaped by the aberrant activity of epigenetic factors that regulate gene expression through the modification of DNA and chromatin. This chapter provides a comprehensive review of the epigenetic alterations in melanoma and highlights the roles played by specific chromatin regulators during disease progression. We also discuss the clinical utility of both first and second generation epigenetic therapies in the melanoma setting, placing emphasis on the potential to overcome resistance to targeted therapies and to serve as priming agents for immunotherapies

The Economics of Fuel Management: Wildfire, Invasive Plants, and the Dynamics of Sagebrush Rangelands in the Western United States

In this article we develop a simulation model to evaluate the economic efficiency of fuel treatments and apply it to two sagebrush ecosystems in the Great Basin of the western United States: the Wyoming Sagebrush Steppe and Mountain Big Sagebrush ecosystems. These ecosystems face the two most prominent concerns in sagebrush ecosystems relative to wildfire: annual grass invasion and native conifer expansion. Our model simulates long-run wildfire suppression costs with and without fuel treatments explicitly incorporating ecological dynamics, stochastic wildfire, uncertain fuel treatment success, and ecological thresholds. Our results indicate that, on the basis of wildfire suppression costs savings, fuel treatment is economically efficient only when the two ecosystems are in relatively good ecological health. We also investigate how shorter wildfire-return intervals, improved treatment success rates, and uncertainty about the location of thresholds between ecological states influence the economic efficiency of fuel treatments

Commercial apple industry of New Hampshire, Bulletin, no. 223

The Bulletin is a publication of the New Hampshire Agricultural Experiment Station, College of Life Sciences and Agriculture, University of New Hampshire, Durham, New Hampshire

Steady Hall Magnetohydrodynamics Near a X-type Magnetic Neutral Line

Hall magnetohydrodynamics (MHD) properties near a two-dimensional (2D) X-type magnetic neutral line in the steady state are considered via heuristic and rigorous developments. Upon considering the steady-state as the asymptotic limit of the corresponding \textit{time-dependent} problem and using a rigorous development, Hall effects are shown to be able to sustain the hyperbolicity of the magnetic field (and hence a more open X-point configuration) near the neutral line in the steady state. The heuristic development misses this subtle connection of the steady state with the corresponding \textit{time-dependent} problem and predicts only an elongated current-sheet configuration (as in resistive MHD). However, the heuristic development turns out to be useful in providing insight into the lack of dependence of the reconnection rate on the mechanism breaking the frozen-in condition of the magnetic field lines. The latter result can be understood in terms of the ability of the ions and electrons to transport equal amounts of magnetic flux per unit time out of the reconnection region.Comment: 1-10 page