13,408 research outputs found
Heat transfer device
An improved heat transfer device particularly suited for use as an evaporator plate in a diffusion cloud chamber. The device is characterized by a pair of mutually spaced heat transfer plates, each being of a planar configuration, having a pair of opposed surfaces defining therebetween a heat pipe chamber. Within the heat pipe chamber, in contiguous relation with the pair of opposed surfaces, there is disposed a pair of heat pipe wicks supported in a mutually spaced relationship by a foraminous spacer of a planar configuration. A wick including a foraminous layer is contiguously related to the external surfaces of the heat transfer plates for uniformly wetting these surfaces
Zero-gravity cloud physics laboratory: Experiment program definition and preliminary laboratory concept studies
The experiment program definition and preliminary laboratory concept studies on the zero G cloud physics laboratory are reported. This program involves the definition and development of an atmospheric cloud physics laboratory and the selection and delineations of a set of candidate experiments that must utilize the unique environment of zero gravity or near zero gravity
The Phoretic Motion Experiment (PME) definition phase
The aerosol generator and the charge flow devices (CFD) chamber which were designed for zero-gravity operation was analyzed. Characteristics of the CFD chamber and aerosol generator which would be useful for cloud physics experimentation in a one-g as well as a zero-g environment are documented. The Collision type of aerosol generator is addressed. Relationships among the various input and output parameters are derived and subsequently used to determine the requirements on the controls of the input parameters to assure a given error budget of an output parameter. The CFD chamber operation in a zero-g environment is assessed utilizing a computer simulation program. Low nuclei critical supersaturation and high experiment accuracies are emphasized which lead to droplet growth times extending into hundreds of seconds. The analysis was extended to assess the performance constraints of the CFD chamber in a one-g environment operating in the horizontal mode
Development of low modulus material for use in ceramic gas path seal applications
Three candidate materials were examined: Brunsbond (R) Pad; plasma sprayed porous NiCrAlY; and plasma sprayed low modulus microcracked zirconia. Evaluation consisted of mechanical, thermophysical, and oxidation resistance testing along with optical microscopy and a feasibility demonstration of attaching the material to a suitable substrate. The goals of the program were the following: feasibility of fastening or depositing the low modulus system onto a broad range of substrate alloys; feasibility of depositing or forming the low modulus system to a thickness of 0.19 cm to 0.38 cm; potential to attain a modulus of elasticity in the range of 3.4 to 6.9 GPa (0.5 to 1.0 MSI), and an ultimate strength of 17.2 MPa (2.5 ksi); suitable thermal conductivity; and static oxidation life of at least 1000 hours at 1311 K. The results of the program indicate that all three systems offer attractive properties as a strain isolator material
E-Procurement Success
The Air Force currently funds projects chartered with studying and developing e-Procurement systems. Through review and analysis of various e-Procurement projects, factors attributing to successful implementation of e-Procurement systems will be deduced and provided as a useful guide for federal agencies initiating e-Procurement projects. By identifying critical success factors this research should: 1) improve preimplementation planning, 2) improve spend decisions, and 3) decrease implementation time by eliminating unnecessary steps. This research utilized the current literature to identify specific factors important in the e-Procurement implementation process. Once the factors were determined, a survey was developed to measure the factors in organizations with an e-Procurement system. All fifty state governments were contacted to determine if they had implemented e-Procurement systems and, if they responded affirmatively, were surveyed regarding what they have identified as the factors most instrumental in their e-Procurement implementation. The survey looked specifically at six key areas of e-Procurement implementation: 1) technology, 2) management, 3) processes, 4) suppliers, 5) budget, and 6) benefits. Each organization\u27s tangible and intangible benefits were assessed to further substantiate the value organizations should be getting from e-Procurement
Development and Testing of a 2-D Transfer CCD
This paper describes the development, operation,
and characterization of charge-coupled devices (CCDs) that feature an electrode structure that allows the transfer of charge both horizontally and vertically through the image area. Such devices have been termed two-dimensional (2-D) transfer CCDs (2DT CCDs), as opposed to the conventional devices, which might be called one-dimensional transfer CCDs, but in other respects are the same as conventional CCD devices. Batches of two different 2DT CCD test devices, featuring different electrode structures but with identical clocking operation in each case, were produced and
tested. The methodology of 2-D charge transfer in each of the device types is described, followed by a presentation of test results from the new CCDs. The ability of both 2DT CCD transfer electrode schemes to successfully transfer charge in both horizontal and vertical directions in the image section of the devices has been proven, opening up potential new applications for 2DT CCD use
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