The Low Energy Beam Transport System of the New GSI High Current Injector

The UNILAC was improved for high current performance by replacing the Wideroe prestripper accelerator by an RFQ and an IH-type DTL. In addition, one of two ion source terminals was equipped with high current sources of MUCIS- and MEVVA-type. Therefore, a redesign of the LEBT from the ion source to the RFQ entrance was necessary. The new LEBT was installed at the beginning of 1999. The commissioning was carried mainly with a high intense argon beam. The achieved 17 emA Ar+ are 6 emA above the RFQ design intensity. The expected performance of the new LEBT was achieved: full transmission for high current beams, preservation of brilliance along the beam line, isotope separation for all elements, transverse phase space matching to the RFQ linac, and macropulse shaping. In particular, the high degree of space charge compensation was confirmed.Comment: Linac 2000, paper MOD15, PDF document with 3 Pages, 7 figure

Dimensional enhancement of kinetic energies

Simple thermodynamics considers kinetic energy to be an extensive variable which is proportional to the number, N, of particles. We present a quantum state of N non-interacting particles for which the kinetic energy increases quadratically with N. This enhancement effect is tied to the quantum centrifugal potential whose strength is quadratic in the number of dimensions of configuration space.Comment: 9 pages, accepted by Phys. Rev.

CHANGES IN GRAIN MARKETING, MARKET STRUCTURE, AND PERFORMANCE IN THE 1980'S

Marketing,

THE CHANGING STRUCTURE OF THE UNITED STATES GRAIN MARKETING SYSTEM

Industrial Organization, Marketing,

Structural Change and Performance of Grain Marketing Cooperatives

The U.S. grain marketing system has undergone many structural changes in the 1980s. In no part of the system has structural change been more far-reaching and extensive than in farmer-owned cooperatives. The purpose of this paper is to analyze changes in grain marketing and induced structural adjustments in grain marketing cooperatives at the local, regional, and interregional levels. The impact of these structural changes on the competitive posture of cooperatives in the grain marketing system is also discussed along with structural adjustments anticipated in the 1990s.Agribusiness,

CASH-FUTURES PRICE RELATIONSHIPS AS GUIDES TO GRAIN MARKETING DECISION-MAKING: CASH BASIS FOR CORN, WHEAT AND SOYBEANS IN MINNESOTA

The purpose of this study is to analyze the relationship between cash and futures prices over the three years 1972-73 through 1974-75 for corn, soybeans, and wheat at selected country locations in Minnesota.Marketing,

Acoustical evaluation of the NASA Lewis 9 by 15 foot low speed wind tunnel

The test section of the NASA Lewis 9- by 15-Foot Low Speed Wind Tunnel was acoustically treated to allow the measurement of acoustic sources located within the tunnel test section under simulated free field conditions. The treatment was designed for high sound absorption at frequencies above 250 Hz and to withstand tunnel airflow velocities up to 0.2 Mach. Evaluation tests with no tunnel airflow were conducted in the test section to assess the performance of the installed treatment. This performance would not be significantly affected by low speed airflow. Time delay spectrometry tests showed that interference ripples in the incident signal resulting from reflections occurring within the test section average from 1.7 dB to 3.2 dB wide over a 500 to 5150 Hz frequency range. Late reflections, from upstream and downstream of the test section, were found to be insignificant at the microphone measuring points. For acoustic sources with low directivity characteristics, decay with distance measurements in the test section showed that incident free field behavior can be measured on average with an accuracy of +/- 1.5 dB or better at source frequencies from 400 Hz to 10 kHz. The free field variations are typically much smaller with an omnidirectional source

Comparison between design and installed acoustic characteristics of NASA Lewis 9- by 15-foot low-speed wind tunnel acoustic treatment

The test section of the NASA Lewis 9- by 15-Foot Low-Speed Wind Tunnel was acoustically treated to allow the measurement of sound under simulated free-field conditions. The treatment was designed for high sound absorption at frequencies above 250 Hz and for withstanding the environmental conditions in the test section. In order to achieve the design requirements, a fibrous, bulk-absorber material was packed into removable panel sections. Each section was divided into two equal-depth layers packed with material to different bulk densities. The lower density was next to the facing of the treatment. The facing consisted of a perforated plate and screening material layered together. Sample tests for normal-incidence acoustic absorption were also conducted in an impedance tube to provide data to aid in the treatment design. Tests with no airflow, involving the measurement of the absorptive properties of the treatment installed in the 9- by 15-foot wind tunnel test section, combined the use of time-delay spectrometry with a previously established free-field measurement method. This new application of time-delay spectrometry enabled these free-field measurements to be made in nonanechoic conditions. The results showed that the installed acoustic treatment had absorption coefficients greater than 0.95 over the frequency range 250 Hz to 4 kHz. The measurements in the wind tunnel were in good agreement with both the analytical prediction and the impedance tube test data

EXPLORING OPTIONS ON DOMESTIC AGRICULTURAL COMMODITIES

Marketing,

WHEAT PRODUCTION IN TUNISIA: TRENDS AND VARIABILITIES

Crop Production/Industries,