The presence of planetary wave type oscillations at mid-latitudes in the mesosphere/lower thermosphere region has been investigated using airglow observations. The observations were taken with a ...Spectral Airglow Temperature Imager (SATI) installed at Sierra Nevada Observatory (37.06 N, 3.38 W) at 2900 m height. Airglow data of the column emission rate of the O sub(2) Atmospheric (0-1) band and of the OH Meinel (6-2) band and deduced rotational temperatures from 1998 to 2007 have been used in this study. From these observations a climatology of planetary wave type oscillations at this location is inferred. It has been found that the planetary wave type oscillations of 5-day period is predominant in our data throughout the year, with activity greater than 50% during March/April and October/November months. The planetary wave type oscillations of 2-day period is predominant during both solstices, being predominant during winter solstice in O sub(2) while a 10-day oscillation appears throughout the year with activity around 20% and with maximum activity during spring and autumn equinoxes. The 16-day oscillation has maximum occurrence during autumn-winter while its activity is almost disappeared during spring-summer. No clear seasonal dependence of the amplitude of the planetary wave type oscillations was observed in the cases considered in this study. The waves simultaneously detected in the rotational temperatures deduced from both OH and O sub(2) emissions usually show an upward energy propagation and are affected by dissipation processes.
The observations of the upper mesosphere region (~95km altitude) in the period of 27-30 March 2006 using mesopause oxygen rotational temperature imager (MORTI) at Almaty (43.03 super(o)N, 76.58 ...super(o)E) are presented in this report to illustrate the mesosphere response to the solar eclipse (SE) event, which occurred on 29 March 2006. The nighttime volume emission rates and rotational temperatures, obtained from MORTI measurements, show appreciable differences in the pattern of wave-like oscillations observed during the period of interest. These oscillations are possibly due to the SE. Using a periodogram method the spectra of the observed wave-like oscillations, observed in the mesosphere, are examined. A physical mechanism is proposed to interpret the effects observed in terms of the mesosphere response to the total SE.
Long-term ground-based airglow observations with a spectral airglow temperature imager (SATI) installed at Sierra Nevada Observatory (37.06°N, 3.38°W) at 2900~m height are used to investigate the ...main features of the quasi planetary waves in the period range of 3-20 days during autumn at this latitude in the mesosphere and lower thermosphere region. The modulations of periods 5 day, (6-7) day, and 10 day have been clearly detected during autumn at this location, being the most prominent waves detected at this location during the autumn. They have a strong persistence during the autumn period and relative amplitudes are generally constant during the period although a slight tendency to increase seems to be detected towards winter.PACS Nos.: 92.60.hw, 92.60.hb, 92.60.hc, 92.60.hh, 92.60.hv
Long-term ground-based airglow observations with a spectral airglow temperature imager (SATI) installed at Sierra Nevada Observatory (37.06°N, 3.38°W) at 2900~m height are used to investigate the ...main features of the quasi planetary waves in the period range of 3–20 days during autumn at this latitude in the mesosphere and lower thermosphere region. The modulations of periods 5 day, (6–7) day, and 10 day have been clearly detected during autumn at this location, being the most prominent waves detected at this location during the autumn. They have a strong persistence during the autumn period and relative amplitudes are generally constant during the period although a slight tendency to increase seems to be detected towards winter.PACS Nos.: 92.60.hw, 92.60.hb, 92.60.hc, 92.60.hh, 92.60.hv
In order to use shape memory Ni–Ti couplings repeatedly for the joining of pipelines, one should know how the multiple mandreling (expansion) affects the temperatures of the phase transformation in ...titanium nickelide and the quality of the inner surface of these couplings. This problem has been studied, using three couplings of commercial Ni–45wt.%Ti (TH1) alloy, which were designed to join the pipelines with an outer diameter of 11.9 mm. During expansion by mandreling the inner diameter of the couplings increased from 11.45 to 12.00 mm. It was observed that the required mandreling force decreased by a factor of 3–4 after a 10-fold mandreling. After each mandreling the coupling was heated, and the temperature of the initial and final stages of the reversible transformation was defined by the change in the inner diameter of the coupling. A decrease of the phase transformation temperatures by 8–20°C was registered between the 2nd and 10th mandreling cycle. In every cycle the average diameter of the coupling and the deviation from the ideal circular shape were measured before mandreling as well as after mandreling and heating and cooling back to room temperature. It was found that the deviation from the ideal circular shape increased with the number of mandreling cycles. This means that the quality of the couplings deteriorates with their repeated expansion by mandreling. This should be taken into account when using the couplings again for the joining of pipelines.
The effect of quenching and high-and low-temperature thermomechanical treatments on the structural changes, the martensitic-transformation kinetics, and the functional shape recovery characteristics ...of a 45Ti-45Ni-10Nb alloy is studied. Electron microprobe and X-ray diffraction analyses are used to determine the structure and phase composition of the alloy and to establish the phase-transformation temperatures up to the appearance of the shape memory effect. The strains inducing the shape memory effect and providing shape recovery at temperatures above room temperature have been found. The maximum reactive stresses have been determined. Based on the studies performed, the conclusion was made that quenching and high-temperature thermomechanical treatment can provide a broad martensitic-transformation hysteresis in the alloy under study and main shape recovery on heating above room temperature. As a result, the alloy can be used as a material for thermomechanical coupling that can be stored at room temperature and is applied to the thermomechanical joint of pipelines on heating above this temperature.PUBLICATION ABSTRACT
is a fixed target experiment working on the 920 GeV proton beam of the HERA accelerator at the DESY laboratory in Hamburg. During the last data taking period (2002-2003), about 150 million dilepton ...triggers, 220 million minimum bias events and 35 million hard photon triggers were acquired. These large statistics allow detailed studies on the production of charmonium states in proton-nucleus p-A collisions, which extend for the first time into the negative Feynman-x () region. Measurements of the inclusive , \(\Upsilon\) and open charm cross sections are also ongoing. After a brief discussion of the detector and of the data samples, we report on preliminary results obtained on these physics topics.
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