Toward the Prevention of Risky Sexual Behavior Among Latina Youth

Sexual risk-taking among Latina youth has been noted as a critical health concern within the United States. In this chapter. the importance of prevention of risky sexual behavior among Latina youth will be discussed. Current prevalence rates and consequences associated with sexual behavior among Latino/as will be reviewed. along with factors that are relevant to understanding the prevention of sexual activity. Finally. programs that have been developed to prevent risky sexual behavior among Latinas will be reviewed and suggestions for prevention efforts will be presented

Review of antiskid and brake dynamics research

The behavior of various antiskid systems was investigated under controlled conditions. Results from utilizing a single main wheel of a DC-9 aircraft suggest that the systems investigated perform well under most circumstances but there may be room for improvement. For example, it was demonstrated that pressure bias modulation can adversely affect the response of antiskid systems to rapid changes in the runway friction level. Results also indicate that antiskid systems designed to operate at a slip ratio of approximately 0.1 can provide a maximum braking effort without undue loss in the cornering capability of the tire. Time histories of braking friction coefficient were shown to provide a means of determining antiskid system performance and for systems that employed pressure bias modulation it was shown that performance could also be estimated from time histories of brake pressure and torque

Status of recent aircraft braking and cornering research

The sources of degraded performance which sometimes occurs under adverse runway conditions, are investigated to obtain data necessary to the development of more advanced systems, in an effort to insure safe ground handling operations under all-weather conditions. Tire-to-ground friction characteristics are determined under braking conditions which closely resemble those of airplanes under heavy braking. Braking data from single-wheel landing loads track tests are related with those available from full-scale flight tests

Experimental validation of a landing-dynamics computer program for legged spacecraft landers

Validation of a landing-dynamics computer program has been accomplished by comparing analytical data with data from a limited experimental program. Agreement obtained established the subject landing-dynamics computer program as a reliable design tool for legged spacecraft landers

Behavior of aircraft antiskid breaking systems on dry and wet runway surfaces: A slip-ratio-controlled system with ground speed reference from unbraked nose wheel

An experimental investigation was conducted at the Langley aircraft landing loads and traction facility to study the braking and cornering response of a slip ratio controlled aircraft antiskid braking system with ground speed reference derived from an unbraked nose wheel. The investigation, conducted on dry and wet runway surfaces, utilized one main gear wheel, brake, and tire assembly of a DC-9 series 10 airplane. During maximum braking, the average ratio of the drag force friction coefficient developed by the antiskid system to the maximum drag force friction coefficient available was higher on the dry surface than on damp and flooded surfaces, and was reduced with lighter vertical loads, higher yaw angles, and when new tire treads were replaced by worn treads. Similarly, the average ratio of side force friction coefficient developed by the tire under antiskid control to the maximum side force friction coefficient available to a freely rolling yawed tire decreased with increasing yaw angle, generally increased with ground speed, and decreased when tires with new treads were replaced by those with worn treads

Technique for measuring side forces on a banked aircraft with a free-swiveling nose gear

An experimental investigation was conducted at the Langley Research Center to determine a method for towing an aircraft to measure the side forces of a free-swiveling nose gear due to variations in bank angle. A F-106 aircraft and the Space Shuttle orbiter OV-101 were towed to measure side forces on full-size aircraft for bank angles up to 3 deg. These tests indicate that substantial side forces will occur if an aircraft is rolling on a runway in a banked attitude even when the nose gear is free to swivel. Corotation of a twin-tire nose gear appears to cause a substantial increase in side force due to bank angle compared with a nose gear with indepdendently rotating wheels

Weight outcomes audit for 34,271 adults referred to a primary care/commercial weight management partnership scheme

Copyright © 2011 S. Karger AG, Basel.Peer reviewedPublisher PD

Fabrication of large tungsten structures by chemical vapor deposition

Process is accomplished by reducing tungsten hexafluoride with hydrogen. Metallic tungsten of essentially 100 percent purity and density is produced and built up as dense deposit on heated mandrel assembly. Process variations are building up, sealing or bonding refractory metals at temperatures below transition temperatures of base metal substrates

Static and yawed-rolling mechanical properties of two type 7 aircraft tires

Selected mechanical properties of 18 x 5.5 and 49 x 17 size, type 7 aircraft tires were evaluated. The tires were subjected to pure vertical loads and to combined vertical and lateral loads under both static and rolling conditions. Parameters for the static tests consisted of tire load in the vertical and lateral directions, and parameters for the rolling tests included tire vertical load, yaw angle, and ground speed. Effects of each of these parameters on the measured tire characteristics are discussed and, where possible, compared with previous work. Results indicate that dynamic tire properties under investigation were generally insensitive to speed variations and therefore tend to support the conclusion that many tire dynamic characteristics can be obtained from static and low speed rolling tests. Furthermore, many of the tire mechanical properties are in good agreement with empirical predictions based on earlier research