Engineering and fabrication cost considerations for cryogenic wind tunnel models

Design and fabrication cost drivers for cryogenic transonic wind tunnel models are defined. The major cost factors for wind tunnel models are model complexity, tolerances, surface finishes, materials, material validation, and model inspection. The cryogenic temperatures require the use of materials with relatively high fracture toughness but at the same time high strength. Some of these materials are very difficult to machine, requiring extensive machine hours which can add significantly to the manufacturing costs. Some additional engineering costs are incurred to certify the materials through mechanical tests and nondestructive evaluation techniques, which are not normally required with conventional models. When instrumentation such as accelerometers and electronically scanned pressure modules is required, temperature control of these devices needs to be incorporated into the design, which requires added effort. Additional thermal analyses and subsystem tests may be necessary, which also adds to the design costs. The largest driver to the design costs is potentially the additional static and dynamic analyses required to insure structural integrity of the model and support system

High effectiveness contour matching contact heat exchanger

There is a need in the art for a heat exchanger design having a flexible core providing contour matching capabilities, which compensates for manufacturing tolerance and distortion buildups, and which accordingly furnishes a relatively uniform thermal contact conductance between the core and external heat sources under essentially all operating conditions. The core of the heat exchanger comprises a top plate and a bottom plate, each having alternate rows of pins attached. Each of the pins fits into corresponding tight-fitting recesses in the opposite plate

Letter to Sonora Dodd from Lewis M. Davenport, Jr., March 30, 1955

Handwritten letter to Sonora Dodd from Lewis M. Davenport, Jr., with envelope.https://digitalcommons.whitworth.edu/fathers-day-correspondence/1111/thumbnail.jp

Supersonic dynamic stability characteristics of a space shuttle orbiter

Supersonic forced-oscillation tests of a 0.0165-scale model of a modified 089B Rockwell International shuttle orbiter were conducted in a wind tunnel for several configurations over a Mach range from 1.6 to 4.63. The tests covered angles of attack up to 30 deg. The period and damping of the basic unaugmented vehicle were calculated along the entry trajectory using the measured damping results. Some parameter analysis was made with the measured dynamic derivatives. Photographs of the test configurations and test equipment are shown

Exploring Memorable Message About Law Enforcement

Research demonstrates that Black Americans are placed at a higher risk for having negative interactions with law enforcement. As a result, Black American families may engage in racial ethnic socialization (RES) practices aimed at preparing Black youth for racialized experiences, reducing the psychological effects of racism, and perserving the lives of Black American citizens. Guided by the memorable messages framework, the present study examines memorable messages about law enforcement as recalled by Black American young adults. More specifically, this study examines the specific type(s) of memorable messages Black American young adults recall receiving about law enforcement from sources such as family and media. To begin, I define and review the literature on the prevalence of racial-ethnic socialization (RES) practices within Black American families before outlining the current study. Followingly, I outline the methodology used to retrieve data before discussing the results of this study. Next, I discuss the theoretical implications associated with the findings of the current study before describing the limitations of this study. Finally, I conclude this study by identifying potential avenues for future research on this topic

A Note on Using Eigenvalues in Dimensionality Assessment

The dimensionality of a set of items is important for scale development. In practice, tools that make use of eigenvalues are often used to assess dimensionality. Parallel analysis is featured here as it is becoming an increasingly popular method for assessing the number of dimensions, and computational tools have recently been made available which will likely increase its use by practitioners. The current paper argues that methods that use eigenvalues to ascertain the number of factors may perform poorly under certain conditions, particularly for increasing levels of variable complexity and/or inter-factor correlations in the latent structure. A simulation study and an example are offered to substantiate this assertion. Accessed 2,400 times on https://pareonline.net from September 06, 2017 to December 31, 2019. For downloads from January 1, 2020 forward, please click on the PlumX Metrics link to the right

Effects of retrorocket exhaust on drag of 120 deg cone at subsonic speeds

Wind tunnel tests to determine effects of retrorocket exhaust on drag of 120 deg cone at subsonic speed

Table of Contents

Contains the table of contents

Author Index

Contains an index of authors

Author Index

Contains an index of authors