3,173 research outputs found
Lessons Learned From the Developmental Flight Testing of the Improved Tactical Air Launched Decoy
The purpose of this thesis is to examine the test team responsibilities and decisions made in the planning, execution, and reporting of test results for the Developmental Flight Testing of the Improved Tactical Air Launched Decoy (ITALD). Information gathered as lead Flight Test Engineer for the series of ITALD flight test events is the primary data source for the opinions formulated in this thesis. Test team decisions, influenced by training, budget constraints, test schedules, and changes in production contractors were analyzed to determine their effect on the flight test program. The Development Test guidance obtained from Department of Defense (DoD) Regulation 5000.2-R, the teachings of the United States Naval Test Pilot School, and other DoD acquisition documentation were reviewed to evaluate test team responsibilities and the approach that was taken throughout the flight test program.
The ITALD Developmental Flight Test program that is examined in this paper consisted of two series of flight tests, the ITALD Baseline Demonstration Flight Test program, which occurred in 1996, and the ITALD DT-IIIE Flight Test Program, which occurred in 1998. Both series of tests are examined since they are similarly related in test team structure, planning and conduct of test, and test results. The major difference between the two series of tests was the reporting of the test results. This will be discussed in detail within this paper.
While the ITALD flight test program was successful in determining what deficiencies existed and what improvements needed to be incorporated, there were a number of lessons learned that were generated. The primary issues that developed were the need to develop a coordinated test philosophy and the necessity to improve communication within the Integrated Program Team. These, along with other lessons learned are discussed within the body of this paper and in the conclusions and recommendations sections
Intestinal neuromuscular function after preservation and transplantation
While it is well known that prolonged preservation of the intestinal graft causes severe mucosal damage after transplantation, little is known about the effect on neuromuscular function. The entire small intestine of adult hound dogs was flushed and preserved with cold lactated Ringer's solution and autotransplanted either immediately (n = 6) or after 24 hr (n = 6). Animals undergoing sham operation (n = 4) were used as a control. Fasting motility and the response of the intestinal smooth muscle and enteric nerves to bethanechol (100 μg/kg/0.5 hr, iv) and cisapride (0.5 mg/kg, iv) were determined by a multiple strain gauge method on Postoperative Days 2, 4, 7, 14, 21, and 28. Compared to the control, immediately transplanted grafts and those preserved for 24 hr developed delayed reappearance of migrating myoelectric complexes (MMC), hypercontractile activity, and reduced response to bethanechol and cisapride administration. Animals in the preservation group developed more abnormal fasting motility after transplantation, but responses to bethanechol and cisapride stimulation were not markedly different from those of the immediate group. The reappearance of MMC occurred 3 weeks postoperatively in the preservation group compared to 2 days in the immediate group. The results of our study indicate that intestinal dysmotility is augmented in prolonged-preservation grafts compared to those with brief preservation. The dysmotility was transient and normalized 3 to 4 weeks after surgery. Preservation and reperfusion injury to the neuromuscular system of intestinal grafts are reversible and are attenuated by simple hypothermia
Reactions of ultracold alkali-metal dimers
We investigate the energetics of reactions involving pairs of alkali-metal dimers. Atom exchange reactions to form homonuclear dimers are energetically allowed for some but not all of the heteronuclear dimers. We carry out high-level electronic structure calculations on the potential energy surfaces of all the heteronuclear alkali-metal trimers and show that trimer formation reactions are always energetically forbidden for low-lying singlet states of the dimers. The results have important implications for the stability of quantum gases of alkali-metal dimers
Reproductive strategies of the insidious fish ectoparasite, Neobenedenia sp. (Capsalidae: Monogenea)
Fish monogeneans are lethal parasites in aquaculture. We provide the first experimental evidence that a notorious fish monogenean, Neobenedenia sp., can produce viable eggs in isolation for three consecutive generations. We infected individual, isolated, farmed barramundi, Lates calcarifer (Bloch) with a single oncomiracidium (larva) of the hermaphroditic monogenean Neobenedenia sp. Isolated parasites reached sexual maturity at day 10 post-hatch (24°C, 35‰) and laid ~3,300 embryonated eggs over 17 days. Egg production rapidly increased following sexually maturity on day 10 (58±15 eggs) and peaked on day 15 (496±68 eggs) before gradually decreasing. Neobenedenia sp. exhibited egg laying and egg hatching rhythms. Parasites laid eggs continuously, but egg production increased in periods of darkness (64.3%), while the majority of oncomiracidia (81%) emerged from eggs in the first three hours of light. Eggs laid by isolated 'parent' parasites hatched and individual emerging oncomiracidia were used to infect more individual, isolated fish, with three consecutive, isolated, parasite generations (F1, F2 and F3) raised in the laboratory. Infection success and egg hatching success did not differ between generations. Our data show that one parasite, in the absence of a mate, presents a severe threat to captive fish populations
Low-energy collisions of NH3 and ND3 with ultracold Rb atoms
We carry out quantum inelastic scattering calculations of collisions of Rb atoms with inverting NH3 and ND3 molecules in the energy range between 0 and 100 cm−1, which are important for experiments using velocity-controlled molecular beams to probe scattering resonances. We focus on molecules initially in the upper level of the ammonia inversion doublet for j=1, k=1, which is low-field seeking and can be controlled in a Stark decelerator. We calculate the integral elastic and state-to-state inelastic cross sections in the coupled-states approximation. We demonstrate the presence of both shape and Feshbach resonances in the elastic and inelastic cross sections at low collision energies and discuss their origin in terms of the bound states of the Rb-ND3 complex. We also consider elastic and inelastic cross sections in the ultracold regime, using close-coupling calculations, in order to assess the viability of sympathetic cooling of ND3 by Rb. The inelastic cross section for relaxation to the lower level of the inversion doublet is smaller than expected for such a strongly coupled system but is still likely to be too large to allow sympathetic cooling for ND3 in low-field-seeking states. However, there is a good prospect that sympathetic cooling will be possible for molecules in high-field-seeking states even when the collision partner is a magnetically trapped atom in a low-field-seeking state
Resource Review
Dynamic Horizons: A Research and Conceptual Summary of Outdoor Education. Written by Chloe Humphreys, Kingston, ON, Council of Outdoor Educators of Ontario, 2018, 77 pp., CDN $20.00 (paperback), ISBN 978-1- 988127- 01-
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