Access

Resource Type

Partner

Collection

Serial/Series Title

Degree Department

Country

States

Counties

Year

Month

Day

Language

562 Matching Results

Start Over Year 2000 Day 19th

Results open in a new window/tab.

prev Results: 553 - 562 of 562

(open access)

Sapulpa Daily Herald (Sapulpa, Okla.), Vol. 84, No. 109, Ed. 1 Wednesday, January 19, 2000

Daily newspaper from Sapulpa, Oklahoma that includes local, state, and national news along with advertising.

Date: January 19, 2000

Creator: unknown

Object Type: Newspaper

System: The Gateway to Oklahoma History

(open access)

Selection Intensity in Genetic Algorithms with Generation Gaps

This paper presents calculations of the selection intensity of common selection and replacement methods used in genetic algorithms (GAs) with generation gaps. The selection intensity measures the increase of the average fitness of the population after selection, and it can be used to predict the average fitness of the population at each iteration as well as the number of steps until the population converges to a unique solution. In addition, the theory explains the fast convergence of some algorithms with small generation gaps. The accuracy of the calculations was verified experimentally with a simple test function. The results of this study facilitate comparisons between different algorithms, and provide a tool to adjust the selection pressure, which is indispensable to obtain robust algorithms.

Date: January 19, 2000

Creator: Cantu-Paz, E.

Object Type: Article

System: The UNT Digital Library

(open access)

The Seminole Sentinel (Seminole, Tex.), Vol. 93, No. 27, Ed. 1 Wednesday, January 19, 2000

Semiweekly newspaper from Seminole, Texas that includes local, state, and national news along with advertising.

Date: January 19, 2000

Creator: Dow, M. Gene & Fisher, David

Object Type: Newspaper

System: The Portal to Texas History

(open access)

Single-mode operation of a coiled multimode fiber amplifier

The authors report a new approach to obtain single-transverse-mode operation of a multimode fiber amplifier, in which the gain fiber is coiled to induce significant bend loss for all but the lowest-order mode. They have demonstrated this method by constructing a coiled amplifier using Yb-doped, double-clad fiber with a core diameter of 25 {micro}m and NA of {minus}0.1 (V {approx} 7.4). When operated as an ASE source, the output beam had an M{sup 2} value of 1.09 {+-} 0.09; when seeded at 1,064 nm, the slope efficiency was similar to that of an uncoiled amplifier. This technique does not require exotic fiber designs or increase system complexity and is inexpensive to implement. It will allow scaling of pulsed fiber lasers and amplifiers to significantly higher pulse energies and peak powers and cw fiber sources to higher average powers while maintaining excellent beam quality.

Date: January 19, 2000

Creator: Koplow, Jeffrey P.; Kliner, Dahv A. V. & Goldberg, Lew

Object Type: Article

System: The UNT Digital Library

(open access)

Social Security Reform: Information on the Archer-Shaw Proposal

A letter report issued by the General Accounting Office with an abstract that begins "Pursuant to a congressional request, GAO provided information on the Archer-Shaw Social Security reform proposal, focusing on: (1) the extent to which the proposal achieves sustainable solvency and how it would affect the U.S. economy and the federal budget; (2) the balance struck between the twin goals of income adequacy (level and certainty of benefits) and individual equity (rates of return on individual contributions); and (3) how readily such changes could be implemented, administered, and explained to the public."

Date: January 19, 2000

Creator: United States. General Accounting Office.

Object Type: Report

System: The UNT Digital Library

(open access)

Suspended Solids Profiler Shop Test Report

The Suspended Solids Profiler (SSP) Instrument is planned to be installed in the AZ-101 tank to measure suspended solids concentrations during mixer pump testing. The SSP sensor uses a reflectance measurement principle to determine the suspended solids concentrations. The purpose of this test is to provide a documented means of verifying that the functional components of the SSP operate properly.

Date: January 19, 2000

Creator: STAEHR, T.W.

Object Type: Report

System: The UNT Digital Library

(open access)

Synthesis of diamondlike carbon films with superlow friction and wear properties

In this study, the authors introduce a new diamondlike carbon (DLC) film providing a friction coefficient of 0.001 and wear rates of 10{sup {minus}9} to 10{sup {minus}10} mm{sup 3}/N.m in inert-gas environments (e.g., dry nitrogen and argon). The film was grown on steel and sapphire substrates in a plasma enhanced chemical vapor deposition system that uses using a hydrogen-rich plasma. Employing a combination of surface and structure analytical techniques, they explored the structural chemistry of the resultant DLC films and correlated these findings with the friction and wear mechanisms of the films. The results of tribological tests under a 10-N load (creating initial peak Hertz pressures of 1 and 2.2 GPa on steel and sapphire test pairs, respectively) and at 0.2 to 0.5 m/s sliding velocities indicated that a close correlation exists between the friction and wear coefficients of DLC films and the source gas chemistry. Specifically, films grown in source gases with higher hydrogen-to-carbon ratios had the lowest fiction coefficients and the highest wear resistance. The lowest friction coefficient (0.001) was achieved with a film on sapphire substrates produced in a gas discharge plasma consisting of 25% methane and 75% hydrogen.

Date: January 19, 2000

Creator: Erdemir, A.; Eryilmaz, O. L. & Fenske, G.

Object Type: Article

System: The UNT Digital Library

(open access)

Tribological behavior of near-frictionless carbon coatings in high- and low-sulfur diesel fuels.

The sulfur content in diesel fuel has a significant effect on diesel engine emissions, which are currently subject to environmental regulations. It has been observed that engine particulate and gaseous emissions are directly proportional to fuel sulfur content. With the introduction of low-sulfur fuels, significant reductions in emissions are expected. The process of sulfur reduction in petroleum-based diesel fuels also reduces the lubricity of the fuel, resulting in premature failure of fuel injectors. Thus, another means of preventing injector failures is needed for engines operating with low-sulfur diesel fuels. In this study, the authors evaluated a near-frictionless carbon (NFC) coating (developed at Argonne National Laboratory) as a possible solution to the problems associated with fuel injector failures in low-lubricity fuels. Tribological tests were conducted with NFC-coated and uncoated H13 and 52100 steels lubricated with high- and low- sulfur diesel fuels in a high-frequency reciprocating test machine. The test results showed that the NFC coatings reduced wear rates by a factor of 10 over those of uncoated steel surfaces. In low-sulfur diesel fuel, the reduction in wear rate was even greater (i.e., by a factor of 12 compared to that of uncoated test pairs), indicating that the NFC coating holds promise …

Date: January 19, 2000

Creator: Alzoubi, M. F.; Ajayi, O. O.; Eryilmaz, O. L.; Ozturk, O.; Erdemir, A. & Fenske, G.

Object Type: Article

System: The UNT Digital Library