Cryogenic seal remains leaktight during thermal displacement

Cryogenic seals protect the surfaces of a plastic member in a low-pressure system subjected to extreme temperature changes. The outer seal is an aluminum expansion ring bonded to the lens outer surface and the inner seal consists of a resin-filled aluminum U-ring bonded to the inner surface

Studies On The Effects Of Centrally Acting Drugs At Increased Pressures Of Air

This thesis examined the effect of selected stimulant and depressant drugs in mice and humans at increased pressures (4 and 7 ata) of air.;In mice, hyperbaric air acted to reduce amphetamine sulphate induced convulsive activity, lethality, and stereotyped licking/biting; in contrast, the locomotor stimulation was enhanced as was that produced by morphine suphate (15 and 30 mg/kg). With regard to the depressants, 7 ata air prolonged the sleep time induced by pentobarbital (45 mg/kg) but had no effect at the lower dose (35 mg/kg). Conversely exposure to hyperbaric air reduced the diphenhydramine (10, 20 mg/kg) - induced depression of activity, and generally increased not decreased the activity of alcohol (1.75 and 2.75 g/kg) - treated mice. Depression of activity with alcohol was only observed at 7 ata at the high dose and was transitory. Studies with appropriate pressures of helium/oxygen confirmed that the alterations of drug effects observed were due to N(,2).;In humans the effects of diphenhydramine (50 and 100 mg) and alcohol (0.25 and 0.375) at 5 ata air on memory and neuromuscular-coordination were determined in two studies. Hyperbaric air impaired memory but not neuromuscular coordination. The drugs, however, did not impair performance, and in general did not significantly worsen performance at pressure. The results indicate that N(,2) at pressures in the air diving range can modify the effects of centrally acting drugs. The modifications, however, are more complex than would be predicted by the concept that N(,2), at least at these pressures, produces a generalized depression of CNS activity. In particular the results in mice suggest that N(,2) may produce both stimulation (disinhibition) and depression of neuronal function, and that the type of modification observed may be dependent on the parameter chosen for study. These latter concepts are compatible with current concepts of anesthetic action, and it is proposed that a hypothesis of N(,2)\u27s effects on CNS function based on current concepts of anesthesia offers a better means of explaining the modification of drugs by hyperbaric air, then one based on older concepts

Residents' annoyance responses to aircraft noise events

In a study conducted in the vicinity of Salt Lake City International Airport, community residents reported their annoyance with individual aircraft flyovers during rating sessions conducted in their homes. Annoyance ratings were obtained at different times of the day. Aircraft noise levels were measured, and other characteristics of the aircraft were noted by trained observers. Metrics commonly used for assessing aircraft noise were compared, but none performed significantly better than A-weighted sound pressure level. A significant difference was found between the ratings of commercial jet aircraft and general aviation propeller aircraft, with the latter being judged less annoying. After the effects of noise level were accounted for, no significant differences were found between the ratings of landings and takeoffs. Aircraft noise annoyance reactions are stronger in lowered ambient noise conditions. This is consistent with the theory that reduced nighttime and evening ambient levels could create different reactions at different times of day. After controlling for ambient noise in a multiple regression analysis, no significant differences were found between the ratings of single events obtained during the three time periods: morning, afternoon, and evenings

Ecology of anthocorid (Hemipt.: Anthocoridae) predators of the pear psylla (Homopt.: Psyllidae) in the Okanagan Valley, British Columbia

The supposition is not valid that the disappearance of the native <i>Anthocoris melanocerus</i> from pear orchards late in the summer is because of competitive displacement by the introduced <i>A. nemoralis</i>. It is because <i>A. melanocerus</i> migrates to where prey are most abundant whereas <i>A. nemoralis</i> remains on pear. <i>A. melanocerus</i> is concentrated on willows in the spring, moves to pear when <i>Psylla pyricola</i> becomes abundant, and moves to cottonwood when aphids on it become abundant and the numbers of <i>P. pyricola</i> on pear have become low

Double layer charging driven carbon dioxide adsorption limits the rate of electrochemical carbon dioxide reduction on Gold.

Electrochemical CO[Formula: see text] reduction is a potential route to the sustainable production of valuable fuels and chemicals. Here, we perform CO[Formula: see text] reduction experiments on Gold at neutral to acidic pH values to elucidate the long-standing controversy surrounding the rate-limiting step. We find the CO production rate to be invariant with pH on a Standard Hydrogen Electrode scale and conclude that it is limited by the CO[Formula: see text] adsorption step. We present a new multi-scale modeling scheme that integrates ab initio reaction kinetics with mass transport simulations, explicitly considering the charged electric double layer. The model reproduces the experimental CO polarization curve and reveals the rate-limiting step to be *COOH to *CO at low overpotentials, CO[Formula: see text] adsorption at intermediate ones, and CO[Formula: see text] mass transport at high overpotentials. Finally, we show the Tafel slope to arise from the electrostatic interaction between the dipole of *CO[Formula: see text] and the interfacial field. This work highlights the importance of surface charging for electrochemical kinetics and mass transport