Received optical power calculations for optical communications link performance analysis

The factors affecting optical communication link performance differ substantially from those at microwave frequencies, due to the drastically differing technologies, modulation formats, and effects of quantum noise in optical communications. In addition detailed design control table calculations for optical systems are less well developed than corresponding microwave system techniques, reflecting the relatively less mature state of development of optical communications. Described below are detailed calculations of received optical signal and background power in optical communication systems, with emphasis on analytic models for accurately predicting transmitter and receiver system losses

Spin-Tunnel Investigation of the Spinning Characteristics of Typical Single-Engine General Aviation Airplane Designs. 1. Low-Wing Model A: Effects of Tail Configurations

The effects of tail design on spin and recovery were investigated in a spin tunnel. A 1/11-scale model of a research airplane which represents a typical low-wing, single engine, light general aviation airplane was used. A tail design criterion for satisfactory spin recovery for light airplanes was evaluated. The effects of other geometric design features on the spin and recovery characteristics were also determined. Results indicate that the existing tail design criterion for light airplanes, which uses the tail damping power factor as a parameter, cannot be used to predict spin-recovery characteristics

Spin-tunnel investigation of the spinning characteristics of typical single-engine general aviation airplane designs. 2: Low-wing model A; tail parachute diameter and canopy distance for emergency spin recovery

A spin tunnel study is reported on a scale model of a research airplane typical of low-wing, single-engine, light general aviation airplanes to determine the tail parachute diameter and canopy distance (riser length plus suspension-line length) required for energency spin recovery. Nine tail configurations were tested, resulting in a wide range of developed spin conditions, including steep spins and flat spins. The results indicate that the full-scale parachute diameter required for satisfactory recovery from the most critical conditions investigated is about 3.2 m and that the canopy distance, which was found to be critical for flat spins, should be between 4.6 and 6.1 m

Controlling external pests of livestock

4 page

The sow and litter : 4-H project

At head of title: University of Missouri College of Agriculture, Agricultural Extension Service."January, 1947.""University of Missouri College of Agriculture and the United States Department of Agriculture Cooperating"--Page 24.Title from cover

Pilot study provides qualitative evidence for intrinsic motivation in schizophrenia spectrum disorders

Persons with schizophrenia spectrum disorders (SSDs) face multiple health barriers that are improved with exercise, but they seldom exercise due to a variety of barriers, of which amotivation is primary. In the current study, we investigated the subjective experiences of persons with SSDs following a formal exercise program. Twenty seven persons with SSDs who had taken part in a 16-week walking program provided feedback during exit interviews. Our purpose was to ascertain whether comments provided evidence of development of intrinsic motivation as defined by Ryan and Deci’s self determination of behavior theory. Our directed content analysis resulted in 5 thematic codes: autonomy, competence, relatedness, health benefits and personal enjoyment. Results highlight the importance of health-related group activities in supporting competence, relatedness and autonomy. Development and testing of interventions to support intrinsic motivation is critical to improving the health of this vulnerable group. DOI:10.4236/ojpsych.2012.22404