Durability and field condition study of seal of SAVY-4000 storage container

The conditions of use for rubber O-rings are at least as important as their physical properties in their effect on the quality of a seal. Under normal use conditions, O-rings may be subject to wear and environmental contaminants such as hair and dirt. This study examines how these factors impact the leak tightness of a nuclear material storage container and the likelihood of the inadvertent release of radioactive material. The durability lifetime of an O-ring was explored by opening and closing four SAVY-4000 1 quart containers 100 times and periodically performing helium leak testing, though no significant change in leak rate was observed. This study also explored how the accumulation of dust or hair on the O-ring surface would affect the leak rate of the containers. A single hair crossing the seal, or a sufficient amount of particulate matter would compromise the seal, but after cleaning, the seal was re-established.     

Chemical-shift micro-imaging of subcutaneous lesions

A chemical-shift imaging technique was used for the study of small subcutaneous lesions. This study concerns micro-imaging of two females suffering from a tenosynovial giant cell tumor and an epidermal cyst. High-resolution water, fat and chemical-shift artifact-free images were obtained on a whole-body MR unit (1.5 T) equipped with a 23-mm microscopy surface coil and standard gradients (23 mT/m). A significant improvement in signal-to-noise ratio was achieved by reducing the receiver bandwidth to values below ±10 kHz. The image data sets were acquired with resolution 0.1×0.13 mm in the plane, slice thickness 0.5 mm and with acquisition time less than 3 min. Spatial resolution, fat suppression, image texture and edge delineation were improved on spectroscopic images compared with those on conventional MR images.     

Enzyme kinetics in acoustically levitated droplets of supercooled water: a novel approach to cryoenzymology

The rate of the alkaline phosphatase-catalyzed hydrolysis of 4-methylumbelliferone phosphate was measured in acoustically levitated droplets of aqueous tris (50 mM) at pH 8.5 at 22 +/- 2 degrees C and in supercooled solution at -6 +/- 2 degrees C. At 22 degrees C, the rate of product formation was in excellent agreement with the rate observed in bulk solution in a cuvette, indicating that the acoustic levitation process does not alter the enzyme activity. The rate of the reaction decreased 6-fold in supercooled solution at -6 +/- 2 degrees C. The acoustic levitator apparatus is described in detail.     

Hairdressers and helping: Influencing the behavior of informal caregivers.

Six 30–55 yr old hairdressers who participated in a 10-wk group mental health consultation and training program were compared with 7 control hairdressers on pre- and posttests of an inventory designed to assess helping strategies. Although on the pretest both groups heavily used the strategies of advice giving and presenting alternatives, only program participants showed an increase in the "reflection of feelings" on the posttest. The consultation program included goals such as (a) maximizing helping effectiveness through modeling and (b) education about referrals within the local mental health network. It is suggested that training in interpersonal help giving be offered to other groups of informal caregivers. (9 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Reliability evaluation and prediction for silicon photodetectors

The electrical parameters of silicon detectors were measured under various external influences (temperature cycling, humidity, salt atmosphere, etc.). The tests were designed and the data were analyzed by using the randomized block design method from the SAS software package. To estimate the lifetime of the detectors, an accelerated lifetime was implemented. Using plots of inspected interval data based on the maximum-likelihood technique (using the software package CENSOR), it was found that the Weibull distribution fits the lifetime test data. The cumulative distribution function and the acceleration factor were calculated; the median lifetime of the silicon detector at room temperature was 8.94×10⁶ hours, and the 95% s-confidence interval was (71.6-10.6)×10⁶ hours     

The cooldown process of superconducting tin films in contact with cold sapphire

Momentary current voltage characteristics of tin-tunnel junctions evaporated on an a-cut sapphire were measured during the cooldown process which starts immediately after stopping the steady-state heating from a constantan heater which was evaporated at the top of the tin diode with a SiO _x -layer in between. The measured momentary current-voltage characteristics cannot be distinguished within experimental error from thermal characteristics taken at a higher substrate temperature. Hence, at the tunnel junction, the electron system can be described at each time during the cooldown process by an electron temperatureT ₁ ^el (t). It is shown that the decay time of the electron system is far too long to be in accordance with a one-temperature model combined with the acoustic mismatch model, which has been verified in pulse-heating experiments during the heatup and steady-state time interval in a preceeding paper.¹ We observed a pure exponential decay of the electron temperature starting at the onset of superconductivity atT _C =3.72 K and ending at the bath temperature which is usually aboutT _C /2. The measured decay constant is within a 10% maximum deviation equal to the effective recombination time _eff of the injected quasiparticles, well-known from other investigations. We found the same dependence of on bath temperature, on the thickness of the tin film, and on oxygen content as was observed for _eff in earlier experiments. Simple models for the behavior of the electron and phonon system during the cooldown process are investigated to explain this unexpected decay behavior at temperatures far away from the bath temperature.