LAWS simulation: Sampling strategies and wind computation algorithms

In general, work has continued on developing and evaluating algorithms designed to manage the Laser Atmospheric Wind Sounder (LAWS) lidar pulses and to compute the horizontal wind vectors from the line-of-sight (LOS) measurements. These efforts fall into three categories: Improvements to the shot management and multi-pair algorithms (SMA/MPA); observing system simulation experiments; and ground-based simulations of LAWS

The Icefield Ranges Research Project, 1971

The 1971 Icefield Ranges Research Project (IRRP) field season again was something of a paradox and, as in past seasons, weather was the guilty agent. Projects that were carried out on the continental slope of the St. Elias Mountains enjoyed relatively good weather; those pursued under the direct influence of Pacific maritime air masses suffered through possibly the worst season weatherwise since the inauguration of IRRP in 1961. Research activity at Kluane Lake camp continued year-round during 1970-1971 for the first time in ten years of operation. ... Base camp is situated on the southern end of Kluane Lake (el. c. 780 m.) and was the hub from which two full-time and four short-term field camps were supported. Air support was provided by the Arctic Institute's versatile STOL supercharged Helio Courier aircraft equipped with ski-wheels aided substantially by a Canadian Forces DeHavilland Buffalo and by two fixed-wing and two rotary-wing aircraft which were chartered locally when necessity demanded. In early July the DeHavilland Buffalo dropped over 4 tons of supplies and equipment to the Mount Logan physiology laboratory (el. c. 5,335 m). Aircraft flew approximately 270 hours in support of IRRP programs in 1971. All base camp facilities were opened for summer field research parties mid-May and were closed 12 September. As in past summers, however, maximum utilization of facilities and research activity occurred between mid-June and mid-August. Principal investigators, senior scientists and graduate students plus their assistants numbered over 70 persons. ... In all more than 100 men and women representing 30 Canadian and American colleges, universities, and research institutions and agencies participated in IRRP field investigations in physical, biological, medical, and social sciences. ... A nominal [glacier studies] program was carried out from mid-July to mid-August on the Rusty Glacier and two neighbours the Backe and Trapridge glaciers, three small surge-type glaciers for which there is evidence of a history of surging. ... During the 1971 summer field season investigations continued into significant changes in the level of Kluane Lake and shifts in direction of drainage .... Active loess transport and deposition studies began 30 May on the wide, dry floor of the Slims River valley. ... Examination of climate continued on three scales of observation here defined as micro-, meso-, and synoptic. ... Research on Dall sheep with emphasis on its range relationship continued throughout the winter. The study area encompasses Sheep Mountain (e. 1,954 m). ... Phytogeographical studies in the Icefield Ranges, begun in 1965 on nunataks and in the alpine zone above the 1,500-m level, were continued in 1971. ... Field laboratory studies [high altitude physiology] were planned to build upon and expand work which had been done in previous years and were for the most part directed towards better understanding of the role of water and salts in acclimatization to hypoxia and in acute mountain sickness. ... The Advanced Research Projects Agency (ARPA) and the Arctic Institute convened a workshop at Kluane Lake camp further to refine and amplify the contributions of energy and mass balance studies. The workshop was held from 23 to 28 August. ..

The Icefield Ranges Research Project, 1970

In 1970 the Icefield Ranges Research Project (IRRP) conducted its tenth consecutive summer of interdisciplinary basic research in the St. Elias Mountains, Yukon Territory, and in the valley and plateau region to the east where all aspects of the environment reflect the influence of those mountains. Summer field investigations began in April and ended the last week in August. And for the first time since the Project's inception in 1961, two programs have continued through the winter (1970-71). This opportunity to continue studies all the year round was made possible by the winterization of a log house; the work, begun in 1967 on the north side of the runway near the Kluane Base Camp, was completed with modern facilities in June 1970. This short paper briefly reviews the programs which were accomplished during the 1970 field season within the broad categories of glaciology, geophysics, physical geography, biology, and human physiology

The Icefield Ranges Research Project, 1969

The Icefield Ranges Research Project (IRRP) - as was visualized nearly ten years ago - becomes each year more and more a complete study of the environment dominated by the St. Elias Mountains, Canada/Alaska. Since 1967, IRRP has been composed of three closely-integrated research units, planned to achieve the proposed aims of IRRP as defined by Dr. W.A. Wood, the original Project Director, accepted by the Arctic Institute's Board of Governors in 1961, and endorsed by the IRRP Advisory Committee. This report reviews the work accomplished by a total of over 65 scientists, their assistants, and support personnel, during the 1969 summer field season, which opened in mid-May and ended the first week in September. It is composed of post-field summaries by principal investigators researching in the disciplines of glaciology, geophysics, physical geography, botany, zoology, archaeology and physiology

Lunar surface engineering properties experiment definition. Volume 1: Mechanics, properties, and stabilization of lunar soils

Lunar soil simulation and stabilization, and impact penetrometer studie

Design of a speed meter interferometer proof-of-principle experiment

The second generation of large scale interferometric gravitational wave detectors will be limited by quantum noise over a wide frequency range in their detection band. Further sensitivity improvements for future upgrades or new detectors beyond the second generation motivate the development of measurement schemes to mitigate the impact of quantum noise in these instruments. Two strands of development are being pursued to reach this goal, focusing both on modifications of the well-established Michelson detector configuration and development of different detector topologies. In this paper, we present the design of the world's first Sagnac speed meter interferometer which is currently being constructed at the University of Glasgow. With this proof-of-principle experiment we aim to demonstrate the theoretically predicted lower quantum noise in a Sagnac interferometer compared to an equivalent Michelson interferometer, to qualify Sagnac speed meters for further research towards an implementation in a future generation large scale gravitational wave detector, such as the planned Einstein Telescope observatory.Comment: Revised version: 16 pages, 6 figure

Influence of Context on Item Parameters in Forced-Choice Personality Assessments

A fundamental assumption in computerized adaptive testing (CAT) is that item parameters are invariant with respect to context – items surrounding the administered item. This assumption, however, may not hold in forced-choice (FC) assessments, where explicit comparisons are made between items included in the same block. We empirically examined the influence of context on item parameters by comparing parameter estimates from two FC instruments. The first instrument was compiled of blocks of three items, whereas in the second, the context was manipulated by adding one item to each block, resulting in blocks of four. The item parameter estimates were highly similar. However, a small number of significant deviations were observed, confirming the importance of context when designing adaptive FC assessments. Two patterns of such deviations were identified, and methods to reduce their occurrences in a FC CAT setting were proposed. It was shown that with a small proportion of violations of the parameter invariance assumption, score estimation remained stable

Sulfuric acid and hydrogen peroxide surface passivation effects on AlGaN/GaN high electron mobility transistors

In this work, we have compared SiNx passivation, hydrogen peroxide, and sulfuric acid treatment on AlGaN/GaN HEMTs surface after full device fabrication on Si substrate. Both the chemical treatments resulted in the suppression of device pinch-off gate leakage current below 1 μA/mm, which is much lower than that for SiNx passivation. The greatest suppression over the range of devices is observed with the sulfuric acid treatment. The device on/off current ratio is improved (from 104–105 to 107) and a reduction in the device sub-threshold (S.S.) slope (from ∼215 to 90 mV/decade) is achieved. The sulfuric acid is believed to work by oxidizing the surface which has a strong passivating effect on the gate leakage current. The interface trap charge density (Dit ) is reduced (from 4.86 to 0.90 × 1012 cm−2 eV−1), calculated from the change in the device S.S. The gate surface leakage current mechanism is explained by combined Mott hopping conduction and Poole Frenkel models for both untreated and sulfuric acid treated devices. Combining the sulfuric acid treatment underneath the gate with the SiNx passivation after full device fabrication results in the reduction of Dit and improves the surface related current collapse

New axially symmetric Yang-Mills-Higgs solutions with negative cosmological constant

We construct numerically new axially symmetric solutions of SU(2) Yang-Mills-Higgs theory in $(3+1)$ anti-de Sitter spacetime. Two types of finite energy, regular configurations are considered: multimonopole solutions with magnetic charge $n>1$ and monopole-antimonopole pairs with zero net magnetic charge. A somewhat detailed analysis of the boundary conditions for axially symmetric solutions is presented. The properties of these solutions are investigated, with a view to compare with those on a flat spacetime background. The basic properties of the gravitating generalizations of these configurations are also discussed.Comment: 18 pages, 7 figures; v2: typos correcte