A statistical model to estimate refractivity turbulence structure constant C sub n sup 2 in the free atmosphere

A computer program has been tested and documented (Warnock and VanZandt, 1985) that estimates mean values of the refractivity turbulence structure constant in the stable free atmosphere from standard National Weather Service balloon data or an equivalent data set. The program is based on the statistical model for the occurrence of turbulence developed by VanZandt et al. (1981). Height profiles of the estimated refractivity turbulence structure constant agree well with profiles measured by the Sunset radar with a height resolution of about 1 km. The program also estimates the energy dissipation rate (epsilon), but because of the lack of suitable observations of epsilon, the model for epsilon has not yet been evaluated sufficiently to be used in routine applications. Vertical profiles of the refractivity turbulence structure constant were compared with profiles measured by both radar and optical remote sensors and good agreement was found. However, at times the scintillometer measurements were less than both the radar and model values

Testing and optimizing MST coaxial collinear arrays, part 6.4A

Many clear-air VHF wind profiles use coaxial collinear (COCO) arrays for their antenna. A COCO array is composed of long lines of half-wave dipoles spaced one-half wavelength apart. An inexpensive method of checking a COCO array is described and its performance is optimized by measuring and then correcting the relative rf phase among its lines at their feed point. This method also gives an estimate of the rf current amplitude among the lines. The strength and location of the sidelobes in the H-plane of the array can be estimated

Determination of U, V, and W from single station Doppler radar radial velocities

The ST/MST (stratosphere troposphere/mesosphere stratosphere troposphere) clear air Doppler radar, or wind profiler, is an important tool in observational meteorology because of its capability to remote observe dynamic parameters of the atmosphere. There are difficulties in transforming the observed radial velocities into meteorological wind components. How this problem has been treated in the past is reviewed, and some of the analysis is recast to a form more suited to the high diagnostic abilities of a number of fixed beam configurations with reference to a linear wind field. The results, in conjunction with other works which treats problems such as the effects of finite sample volumes in the presence of nonhomogeneous atmospheric reflectivity, have implications important to the design of both individual MST/ST radars and MST/ST radar networks. The key parameters to uncoupling terms in the scaling equations are w sub x and w sub y. Whenever the stratiform condition, which states that these two parameters are negligible, is satisfied, a five beam ST radar may determine unbiased values of u, v, and w for sample volumes directly above the radar. The divergence and partial deformation of the flow may also be determined. Three beam systems can determine w and w sub z, but are unable to obtain u and v wind components uncontaminated by vertical sheer terms, even when the stratiform condition is satisfied

Recent results at the Sunset radar

The Sunset radar is a VHF, pulsed Doppler radar located in a narrow canyon near the Sunset townsite 15 km west of Boulder, CO. This facility is operated by the Aeronomy Laboratory, ERL, NOAA, exclusively for meteorological research and the development of the mesosphere-stratosphere-troposphere (MST) and stratosphere-troposphere (ST) radar technique. Recent results include a measurement of all three components of wind velocity for the Federal Administration

A comparison of vertical velocities measured from specular and nonspecular echoes by a VHF radar

For a number of years, there have been doubts about the accuracy of vertical wind velocities measured with quasi-specular reflections from mesosphere-stratosphere-troposphere (MST) radar. The concern has been that the layers producing the quasi-specular reflection process this hypothetical tilt. Because of the quasi-specular reflection process, this hypothetical tilt would control the effective zenith angle of the radar antenna beam so that a small component of the horizontal velocity would be included in what was assumed to be a truly vertical beam. The purpose here is to test the hypothesis that there is an effect on the wind velocities measured on a vertical antenna beam due to a long-term tilting of the stable atmospheric layers that cause quasi-specular reflection. Gravity waves have been observed to cause short-term tilting of turbulent layers and specularly reflecting layers. In both cases, the effect was a wave-like deformation atmospheric layers with a period of a few minutes. This geometry is shown. Because of this influence of gravity waves, it was expected that there would be short-term variations in the vertical velocity

Teachers' perceptions of how attention-deficit/hyperactivity disorder may influence learners' career choices

This article reports on teachers’ perceptions of how ADHD may influence learners’ career choices. Purposive selection was used to identify six high school teachers who cater specifically for learners with Attention-Deficit/Hyperactivity Disorder (ADHD). An exploratory case study design and a qualitative approach were adopted. Data was gathered using an audio-recorded semi-structured focus group interview, and analysed and interpreted using inductive thematic analysis. Findings suggest teachers believe that ADHD affects parents, schooling, and the school environment from an early age, that taking medication for ADHD from an early age may positively and negatively influence affect learners’ career choices, and that intervention to address the longer-term impact of ADHD on learners’ career choices is essential. Moreover, teachers believe that parents play a powerful role in the career choice of learners with ADHD. Future research should include early childhood carers, teachers and other health professionals, and include larger and more diverse groups of participants

The difficulties experienced by nurses and healthcare staff involved in the process of breaking bad news

AIMS: To explore the difficulties experienced by nurses and healthcare professionals when engaging in the process of breaking bad news BACKGROUND: The challenges faced by staff when breaking bad news have previously been researched in relation to particular settings or subjects. This study involved staff from diverse settings and roles to develop broader insights into the range of difficulties experienced in clinical practice. DESIGN: The study used a descriptive survey design involving self-reported written accounts and framework analysis. METHODS: Data were collected using a structured questionnaire containing a free text section that asked participants to describe a difficult experience they had encountered when involved in the process of breaking bad news. Data were collected from healthcare staff from hospital, community, hospice and care home settings attending training days on breaking bad news between April 2011 - April 2014. FINDINGS: Multiple inter-related factors presented challenges to staff engaging in activities associated with breaking bad news. Traditional subjects such as diagnostic and treatment information were described but additional topics were identified such as the impact of illness and care at the end of life. A descriptive framework was developed that summarises the factors that contribute to creating difficult experiences for staff when breaking bad news. CONCLUSION: The framework provides insights into the scope of the challenges faced by staff when they engage in the process of breaking bad news. This provides the foundation for developing interventions to support staff that more closely matches their experiences in clinical practice. This article is protected by copyright. All rights reserved

Study of an advanced transport airplane design concept known as Flatbed

The design concept and configuration of the Flatbed transport aircraft are presented. The Flatbed configuration combines into one frame, the ability to haul cargo, virtually unrestrained by cross sectional dimensions of the fuselage. The feasibility and capability of the Flatbed is discussed in depth

An Analytical Study for Subsonic Oblique Wing Transport Concept

The oblique wing concept has been investigated for subsonic transport application for a cruise Mach number of 0.95. Three different mission applications were considered and the concept analyzed against the selected mission requirements. Configuration studies determined the best area of applicability to be a commercial passenger transport mission. The critical parameter for the oblique wing concept was found to be aspect ratio which was limited to a value of 6.0 due to aeroelastic divergence. Comparison of the concept final configuration was made with fixed winged configurations designed to cruise at Mach 0.85 and 0.95. The crossover Mach number for the oblique wing concept was found to be Mach 0.91 for takeoff gross weight and direct operating cost. Benefits include reduced takeoff distance, installed thrust and mission block fuel and improved community noise characteristics. The variable geometry feature enables the final configuration to increase range by 10% at Mach 0.712 and to increase endurance by as much as 44%