Performance Test

Accessions of cultivated barley (Hordeum vulgare ssp. vulgare) and its wild progenitor Hordeum vulgare ssp. spontaneum (H. ssp. spont.) were screened for gramine content at the seedling stage. H. ssp. spont. generally had higher gramine concentration compared with cultivated spring barley. Thus gramine concentrations might be raised in modern barley through crossings with selected H. ssp. spont. accessions and repeated back-crossings (BC) of selected offspring to cultivated barley. In the present study, the barley cultivar Lina was used as the recurrent parent. Lina was exceptional among the two-rowed barleys in that it contained moderate levels of gramine, whereas most of the others were very low in gramine. Chromosome-doubled haploid lines (DHs) from the first generation (F1) had a skewed distribution towards higher gramine concentrations and so had the first back-cross generation (BC1F1-DHs). A hairy plant surface, another character proposed to confer resistance to aphids, was al...

A new facility for 14C-AMS dating and for studies on cultural heritage by ion beam analysis has been put in operation at the University of Lecce, Lecce, Italy. The system is based on a 3 MV TandetronTM accelerator, manufactured by High Voltage Engineering Europa (HVEE). In the 14C-AMS system the three carbon isotopes are injected sequentially in the accelerator with cycle frequencies of up to 1 kHz. Performance tests have shown that the beams can be transported without any loss through the system. The 13C/12C precision of the system is 0.04% and no significant drift in the measured ratios is present.

In this work, the integration between data provided by Time-of- light cameras and a multi-image matching technique for metric surveys of architectural elements is presented. The main advantage is given by the quickness in the data acquisition (few minutes) and the reduced cost of the instruments. The goal of this approach is the automatic extraction of the object breaklines in a 3D environment using a photogrammetric process, which is helpful for the final user exigencies for the reduction of the time needed for the drawing production. The results of the performed tests on some architectural elements will be reported in this paper.

Background: Studies concerning the reliability of individual sacroiliac tests have inconsistent results. It has been suggested that the use of a test regimen is a more reliable form of diagnosis than individually performed tests. Objective: To assess the interrater reliability of multitest scores by using a regimen of 5 commonly used sacroiliac pain provocation tests. Methods: Two examiners examined 78 subjects. The threshold for a positive selection was set at 3 positive tests out of 5 tests performed. The test order and the order in which the subjects were examined were randomized per patient, and the examiners were blinded from all information regarding the subjects tested. Fifty-nine of the subjects were symptomatic for low back pain, and 19 of the subjects were asymptomatic. Weighted kappa statistic, bias-adjusted kappa, prevalence-adjusted kappa, and 95% CI intervals were used to evaluate the interrater reliability of the test regimen. Results: Weighted kappa was found to be 0.70 (95% CI = 0.45-0.95). Conclusions: A multitest regimen of 5 sacroiliac joint pain provocation tests is a reliable method to evaluate sacroiliac joint dysfunction, although further study is needed to assess the validity of this test method.

Resistojets operating at low power (less than lOO W) and using liquid propellants have re-emerged as attractive propulsion options for orbit-raising small satellites deployed at Space Shuttle altitudes (approx. 2OO km). Compared to low power pulsed plasma thrusters (PPT), the resistojet produces two orders of magnitude more thrust (approximately 1.4 mN compared to 140 mN) which is required to overcome drag at solar maximum. The wet mass of both systems is approximately equal although the propellant volume for the PPT is significantly lower since it is stored in solid form. The major disadvantage of the resistojet propulsion system compared to the PPT, is in the complexity added from the propellant tanks. Shuttle integration concerns for the solid Teflon (trademark) propellant of the PPT are minimal or non-existent. Although non-toxic, the water or nitrous oxide propellant of the resistojet requires pressurized tanks and valves which increase safety requirements. To investigate the usefulness of the resistojet for small satellite applications, a series of performance tests have been completed at the AFRL Electric Propulsion Laboratory using the JPL inverted pendulum thrust stand. The tests were conducted for two types of resistojet thrusters developed at the University of Surrey which utilize a packed bed of SiC particles for the heat exchanger. Performance testing eas accomplished at power levels from 0-600 W for five propellants: water, nitrous oxide, water/ methanol, nitrogen, and helium. Two endurance tests were conducted to determine possible failure modes. Performance characterization and thermal models were developed for future design applications of these thrusters. Future USAF and Surrey Satellite Technology, Ltd. (SSTL) missions using these resistojets are also discussed.

Control techniques that optimize the behaviour of pulse-width modulation (PWM) rectifiers for magnet supplies are examined. Different control strategies, both with preprogrammed and variable switching patterns, are examined and compared in terms of optimization of the system performance. Optimum digital PWM, multilevel delta modulation, and hybrid PWM/delta techniques are analyzed. The validity of the control methods was verified by simulation and experimental tests on a 60 kW prototype. It was observed that, in practice, digital PWM techniques are better suited for optimizing the AC converter performance, while delta modulation techniques give better results in terms of DC current and voltage distortion.>

The aim of this paper is to investigate, for the first time, the performance of trading strategies based on the combination of technical trading rules and fundamental analysis in the sale and purchase market for dry bulk ships. Using a sample of price and charter rates over the period January 1976 to September 2004, we establish the existence of a long-run cointegrating relationship between price and earnings and use this relationship as an indicator of investment or divestment timing decisions in the dry bulk shipping sector. In order to discount the possibility of data snooping biases and to evaluate the robustness of our trading models, we also perform tests using the stationary bootstrap approach. Our results indicate that trading strategies based on earnings–price ratios significantly out-perform buy and hold strategies in the second-hand market for ships, especially in the market for larger vessels, due to higher volatility in these markets.