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Optical Methods Involving Light Scattering for Measuring Size and Concentration of Condensation Particles in Supercooled Hypersonic Flow

Description: Note presenting a discussion of optical methods involving light scattering for measuring the size and concentration of condensation particles in supercooled hypersonic air flow. Two methods based on scattered-light measurements and transmitted-light measurements can be given when three specific conditions are met.
Date: August 1951
Creator: Durbin, Enoch J.
Partner: UNT Libraries Government Documents Department

Accuracy evaluation of residual stress measurements

Description: The accuracy of residual stress measurement techniques is difficult to assess due to the lack of available reference standards. To satisfy the need for reference standards, two specimens were designed and developed to provide known stress magnitudes and distributions: one with a uniform stress distribution and one with a nonuniform linear stress distribution. A reusable, portable load fixture was developed for use with each of the two specimens. Extensive bench testing was performed to determine if the specimens provide desired known stress magnitudes and distributions and stability of the known stress with time. The testing indicated that the nonuniform linear specimen and load fixture provided the desired known stress magnitude and distribution but that modifications were required for the uniform stress specimen. A trial use of the specimens and load fixtures using hole drilling was successful.
Date: May 1, 1996
Creator: Yerman, J.A.; Kroenke, W.C. & Long, W.H.
Partner: UNT Libraries Government Documents Department

First positron annihilation lifetime measurement of Pu

Description: We have made the first measurement of defects in an aged sample of {delta} phase, Ga stabilized Pu, using positron annihilation lifetime spectroscopy. This measurement validates the procedure necessary to perform measurements on this highly toxic material and obtain data representative of sample conditions. Comparison of the positron annihilation lifetime analysis of the data with calculated values suggests that He filled vacancies or vacancy clusters dominate the defect population. Such defects are the necessary precursor to void growth and swelling. The evolution of defects resulting from the radioactive decay of Pu during its life in the stockpile is one of the unknown quantities affecting our confidence in predictions of the limit on stockpile components. Radiation damage leads to changes in the size and strength of metals studied for reactor and accelerator use and similar effects may be expected in Pu. The evolution of radiation produced vacancies into larger void structures and accompanying macroscopic swelling may occur in Pu at some age. A detailed understanding of the defects in self irradiated Pu is required to predict the time scale of void swelling and related radiation effects. 1 fig.
Date: November 21, 1996
Creator: Colmenares, C.; Howell, R.H.; Ancheta, D.; Cowan, T.; Hanafee, J. & Sterne, P.
Partner: UNT Libraries Government Documents Department

LCR bridge measurements at elevated operating levels

Description: A critical part in the design of high voltage systems is the selection of the appropriate discrete components The proper selection involves consideration to the basic equivalent electrical parameters of inductance, capacitance, and resistance. The typical approach to establish these parameters involves the use of low level measurements at reduce scale and extrapolate the results to the desired operating ranges. A test voltage level of one volt represents the typical low- level measurement system. The linearity of this process is always in question and may not represent the system operating parameters. The following technique involves the use of a standard Hewlett Packard LCR bridge to measure the electrical parameters of a selected component while it is at its operating level. This process not only provides discrete component values at operating stress but also provides limited information of frequency information at the internal frequency steps. Capacitance is the principal parameter of interest and is highly stress related The significance of a varying capacitance as a function of voltage is the direct relationship to the available stored energy Additional concerns of system frequency response depend on the application.
Date: December 1, 1997
Creator: Wilson, M.J., LLNL
Partner: UNT Libraries Government Documents Department

Measuring and adjusting the path length at CEBAF

Description: Accurately setting the path length around the machine is central to the proper operation of the CEBAF accelerator. The CEBAF main accelerator consists of two recirculating superconducting linacs operating at 1497 MHz fundamental frequency. The electron beam can recirculate up to five times through the two linacs before it is extracted to the experimental halls. In order to obtain maximum energy gain and minimum energy spread through the linacs, all passes should arrive at the beginning of the linacs in phase at the crest of the RF cycle. In this paper we explain how the arrival times of higher pass beams are measured with respect to the first pass to less than one degree of RF phase and how the path length around the machine is adjusted. Following a brief introduction to the CEBAF design and some local nomenclature, these topics will be discussed: differential RF phase measurements of time delay, the energy method of cresting the higher pass beams, results obtained with the measurement techniques, future plans and improvements to the devices, and finally, a set of conclusions. 3 refs., 5 figs., 1 tab.
Date: December 31, 1995
Creator: Krafft, G.A.; Crofford, M. & Douglas, D.R.
Partner: UNT Libraries Government Documents Department

Application of proposed mutual reciprocal inspection measurement techniques to a weapon component

Description: The shape-measurement technique proposed by Russian scientists for mutual reciprocal inspections (MRI) of plutonium from dismantled nuclear weapons has been applied to a US weapon component. Measurement procedures are described. Results of the measurements are {open_quotes}self-normalized{close_quotes} to remove any classified information and further renormalized to results of previous joint US/Russian measurements of an unclassified plutonium piece. Data are presented in tabular and graphical form, conforming to the method of presentation recommended by Russian experts during the previous measurements.
Date: April 1, 1997
Creator: Johnson, M.W.; Frankle, C.M. & Gosnell, T.B.
Partner: UNT Libraries Government Documents Department

Phase and synchronous detector theory as applied to beam position and intensity measurements

Description: A popular signal processing technique for beam position measurements uses the principle of amplitude-to-phase (AM/PM) conversion and phase detection. This technique processes position-sensitive beam-image-current probe-signals into output signals that are proportional to the beam`s position. These same probe signals may be summed and processed in a different fashion to provide output signals that are proportional to the peak beam current which is typically referred to as beam intensity. This paper derives the transfer functions for the AM/PM beam position and peak beam current processors.
Date: May 1, 1995
Creator: Gilpatrick, J.D.
Partner: UNT Libraries Government Documents Department

Update on the National Center for Gear Metrology

Description: Traceability to national or international standards is clearly required by commercial sector standards including ISO 9001:1994 (Ref. 1), ISO/IEC Guide 25 (Ref. 2), and the US equivalent of ISO/IEC Guide 25-ANSI/NCSL Z540-2-1997 (Ref. 3). In the draft replacement to ISO/IEC Guide 25-ISO 17025; measurements, not just equipment, must be traceable to SI units or reference to a natural constant. The implications of traceability to the US gear industry are significant. In order to meet the standards, either gear manufacturers must have calibrated artifacts or must establish their own traceability to SI units.
Date: September 26, 2000
Creator: Cox, B. L.
Partner: UNT Libraries Government Documents Department

Visualization of micro-scale phase displacement processes in retention and outflow experiments: Non-uniqueness of unsaturated flow properties

Description: Methods to determine unsaturated hydraulic properties can exhibit random and non-unique behavior. The authors assess the causes for these behaviors by visualizing micro-scale phase displacement processes during equilibrium retention and transient outflow experiments. They observe that the drainage process is composed of a fast fingering followed by a slower backfilling. The influence of each these processes is controlled by the size and the speed of the applied boundary step, the initial saturation and its structure and by small-scale heterogeneities. Because the mixture of these micro-scale processes yields macro-scale effective behavior, measured unsaturated flow properties are also a function of these controls. These results suggest limitations on the current definitions and uniqueness of unsaturated hydraulic properties.
Date: March 9, 2000
Partner: UNT Libraries Government Documents Department

Measurement of {gamma}{sub T} with the {gamma}{sub T} quads on and off

Description: An experimental procedure for measuring {gamma}{sub T} has been developed and tested in two different measurements, with the {gamma}{sub T} quads on and off. The results were compared to MAD calculations. The discrepancy between the measured {gamma}{sub T} and the calculated {gamma}{sub T} is less than 5%.
Date: May 24, 2004
Creator: Xi Yang, James MacLachlan and Charles M. Ankenbrandt
Partner: UNT Libraries Government Documents Department

Surveying the monument system at Lawrence Berkeley Laboratory`s Advanced Light Source accelerator

Description: Particle accelerators with demanding alignment requirements face a need for periodic re-surveying of their reference monument systems. At the ALS, significant foundation settling and the necessary relocation of some floor monuments mean that the entire system of over 100 monuments must be re-surveyed to an accuracy of 100 microns at two year intervals. Last Fall, the monument survey was conducted entirely by the in-house Survey and Alignment crew using a simplified instrument mounting system and an inexpensive commercial software package. Precision levels, plummets, theodolites, and an electronic distance measuring system were used with the innovative ``Monopod`` instrument mounting system in a cost effective approach to this critical task.
Date: April 1, 1995
Creator: Thur, W. & Lauritzen, T.
Partner: UNT Libraries Government Documents Department

Topical Report: Task 1.4 Correlation of Capillary Suction Time with Leak-Off Behavior

Description: Core Leak-off tests are commonly used to ascertain the ability of a drilling fluid to seal permeable rock under downhole conditions. Unfortunately, these tests are expensive and require a long time to set up. To monitor fluid invasion trends and to evaluate potential treatments for reducing fluid invasion on location, a simpler screening test is highly desirable. The Capillary Suction Time (CST) Test has been used since the 1970's as a fast, yet reliable, method for characterizing fluid filterability and the condition of colloidal materials in water treatment facilities and drilling fluids. For the latter, it has usually been applied to determine the state of flocculation of clay-bearing fluids and to screen potential shale inhibitors. In this work, the CST method was evaluated as a screening tool for predicting relative invasion rates of drilling fluids in permeable cores. However, the drilling fluids examined--DRILPLEX, FLOPRO, and APHRON ICS--are all designed to generate low fluid loss and give CST values that are so high that fluid invasion comes to be dominated by experimental artifacts, such as fluid evaporation. As described in this work, the CST procedure was modified so as to minimize such artifacts and permit differentiation of the fluids under investigation.
Date: December 17, 2004
Creator: Hoff, Tatiana & Growcock, Fred
Partner: UNT Libraries Government Documents Department