Apparatus and method for generating large mass flow of high temperature air at hypersonic speeds

High temperature, high mass air flow and a high Reynolds number test air flow in the Mach number 8-10 regime of adequate test flow duration is attained by pressurizing a ceramic-lined storage tank with air to a pressure of about 100 to 200 atmospheres. The air is heated to temperatures of 7,000 to 8,000 R prior to introduction into the tank by passing the air over an electric arc heater means. The air cools to 5,500 to 6,000 R while in the tank. A decomposable gas such as nitrous oxide or a combustible gas such as propane is injected into the tank after pressurization and the heated pressurized air in the tank is rapidly released through a Mach number 8-10 nozzle. The injected gas medium upon contact with the heated pressurized air effects an exothermic reaction which maintains the pressure and temperature of the pressurized air during the rapid release

Experimental results of high-current arcs driven supersonically in straight and circular channels

High current electric arc characteristics magnetically driven to supersonic velocities in straight and circular channel

Numerical and experimental studies of the natural convection within a horizontal cylinder

Numerical solutions are obtained for the quasi-compressible Navier-Stokes equations governing the time-dependent natural convection within a horizontal cylinder. The early flow development and wall heat transfer are obtained after a uniformly cold wall is imposed as a boundary condition on the cylinder. Results are also obtained for a time-varying cold wall as a boundary condition with windward explicit differencing used for the numerical solutions. The viscous truncation error associated with this scheme is controlled so that first-order accuracy is maintained in time and space. Experiments within a small-scale instrumented horizontal cylinder revealed the time development of the temperature distribution across the boundary layer as well as the decay of wall heat transfer with time. Agreement between temperature distributions obtained experimentally and numerically was generally good. The time decay of the dimensionless ratio of the Nusselt number to the one-fourth power of the Grashof number is found both numerically and experimentally, and good agreement is obtained between these two results over most of the cylinder wall

Environmental npp related risk assessment and its communication to the public

Тези авторів присвячені екологічній оцінці ризиків, пов'язаних з АЕС та її зв'язок з громадськіст

Trained and Amphetamine-Induced Circling Behavior in Lesioned, Transplanted Rats

Rats were trained to turn for water reinforcement and then were given unilateral 6- hydroxydopamine lesions. After lesion, rats showed deficits in trained turning both contraand ipsilateral to the side of the lesion, with contralateral turning more severely impaired. The lesioned rats were then transplanted with fetal mesencephalic dopamine tissue into striatum. A control group of lesioned rats were sham transplanted. Four weeks after transplant, 1.5 mg/kg D-amphetamine challenge injections were used to test the functioning of the transplants. In the control rats, D-amphetamine induced ipsilateral turning; in transplanted rats, D-amphetamine slowed the rate of ipsilateral turning or reversed the direction of amphetamine-induced rotation. Only rats which reversed their, amphetamine-induced turn direction after transplant were used for the rest of the experiment. Trained turning was assessed at 4, 8, 12 and 16 weeks post transplant. Transplants did not improve learned performance at any time post transplant. When D-amphetamine was administered in conjunction with the trained turning sessions, a low dose (0.12 mg/kg) enhanced contralateral trained turn rates, without affecting ipsilateral turn rates. Higher doses of amphetamine reduced ipsilateral turn rate in the transplanted animals. The results of this study suggest that transplants alone do not reinstate performance of conditioned rotation

SOME SOCIOECONOMIC COMPONENTS IN THE LIFE OF PERSONS AFFECTED BY RHEUMATOID ARTHRITIS

Socioekonomski faktori imaju značajnu ulogu u kvaliteti života oboljelih od reumatoidnog artritisa. Istraživanja je provedeno na uzorku od 77 oboljelih od reumatoidnog artritisa registriranih u Službi za fizikalnu medicinu i rehabilitaciju Medicinskog centra »Dr Dragomir Drakulić Puba«. Ispitan je bio obrazovni nivo, bračni status, utjecaj psihičkiih stresova na oboljenje, odlazak u mirovinu, uvjeti stanovanja. Ispitivanje je provedeno metodom anketnog upitnika, usmenim intervjuima i uvidom u medicinsku dokumentaciju. Utvrđeno je da su socioekonomski komponente života ispitanika kao; obrazovni nivo, radni status i uvjeti stanovanja nezadovoljavajući. Psihički stresovi značajnije djeluju na pogoršanje toka bolesti. Zaključuje se da je uz medicinsko liječenje potrebno provoditi edukaciju bolesnika, socijalnu i defektološku rehabilitaciju. U tim za liječenje oboljelih od reumatoidnog artritisa potrebno je uključiti i paramedicinske stručnjake.Socoeconomic factors play a significant role in the quality of life of the persons affected by rheumatoJd arthritis. In this study were included 77 patients on Lile at the Physical Medicine and Rehabilitation service at the Medical Centre »Dr Dragomir Drakulić Puba«. Education rate, merita! status, influence of psychological stress of illness, number of patients retired on disablement pension, and housing condition were determined. The subjects answered a questionaire formely pretested and validated. The method of [ntervuing the patients has also been used. It has been found that :the educational background is markedly low. The patients are retired on a disablement pension ll years before the usual age limit. Only 21% worked full hours, 73% lived in inadequate, humid housing. Psychological stress is significant factor of worsened illness. In conclusion has been stressed that the medical treatment has to be expanded with psycho-social rehabilitation

Temporal changes in endmember abundances, liquid water and water vapor over vegetation at Jasper Ridge

Imaging spectrometry offers a new way of deriving ecological information about vegetation communities from remote sensing. Applications include derivation of canopy chemistry, measurement of column atmospheric water vapor and liquid water, improved detectability of materials, more accurate estimation of green vegetation cover and discrimination of spectrally distinct green leaf, non-photosynthetic vegetation (NPV: litter, wood, bark, etc.) and shade spectra associated with different vegetation communities. Much of our emphasis has been on interpreting Airborne Visible/Infrared Imaging Spectrometry (AVIRIS) data spectral mixtures. Two approaches have been used, simple models, where the data are treated as a mixture of 3 to 4 laboratory/field measured spectra, known as reference endmembers (EM's), applied uniformly to the whole image, to more complex models where both the number of EM's and the types of EM's vary on a per-pixel basis. Where simple models are applied, materials, such as NPV, which are spectrally similar to soils, can be discriminated on the basis of residual spectra. One key aspect is that the data are calibrated to reflectance and modeled as mixtures of reference EM's, permitting temporal comparison of EM fractions, independent of scene location or data type. In previous studies the calibration was performed using a modified-empirical line calibration, assuming a uniform atmosphere across the scene. In this study, a Modtran-based calibration approach was used to map liquid water and atmospheric water vapor and retrieve surface reflectance from three AVIRIS scenes acquired in 1992 over the Jasper Ridge Biological Preserve. The data were acquired on June 2nd, September 4th and October 6th. Reflectance images were analyzed as spectral mixtures of reference EM's using a simple 4 EM model. Atmospheric water vapor derived from Modtran was compared to elevation, and community type. Liquid water was compare to the abundance of NPV, Shade and Green Vegetation (VG) for select sites to determine whether a relationship existed, and under what conditions the relationship broke down. Temporal trends in endmember fractions, liquid water and atmospheric water vapor were investigated also. The combination of spectral mixture analysis and the Modtran based atmospheric/liquid water models was used to develop a unique vegetation community description

Mapping and monitoring changes in vegetation communities of Jasper Ridge, CA, using spectral fractions derived from AVIRIS images

An important application of remote sensing is to map and monitor changes over large areas of the land surface. This is particularly significant with the current interest in monitoring vegetation communities. Most of traditional methods for mapping different types of plant communities are based upon statistical classification techniques (i.e., parallel piped, nearest-neighbor, etc.) applied to uncalibrated multispectral data. Classes from these techniques are typically difficult to interpret (particularly to a field ecologist/botanist). Also, classes derived for one image can be very different from those derived from another image of the same area, making interpretation of observed temporal changes nearly impossible. More recently, neural networks have been applied to classification. Neural network classification, based upon spectral matching, is weak in dealing with spectral mixtures (a condition prevalent in images of natural surfaces). Another approach to mapping vegetation communities is based on spectral mixture analysis, which can provide a consistent framework for image interpretation. Roberts et al. (1990) mapped vegetation using the band residuals from a simple mixing model (the same spectral endmembers applied to all image pixels). Sabol et al. (1992b) and Roberts et al. (1992) used different methods to apply the most appropriate spectral endmembers to each image pixel, thereby allowing mapping of vegetation based upon the the different endmember spectra. In this paper, we describe a new approach to classification of vegetation communities based upon the spectra fractions derived from spectral mixture analysis. This approach was applied to three 1992 AVIRIS images of Jasper Ridge, California to observe seasonal changes in surface composition

Temporal variation in spectral detection thresholds of substrate and vegetation in AVIRIS images

The ability to map changes over large surface areas over time is one of the advantages in using remote sensing as a monitoring tool. Temporal changes in the surface may be gradual, making them difficult to detect in the short-term, and because they commonly occur at the subpixel scale, they may be difficult to detect in the long-term as well. Also, subtle changes may be real or merely an artifact of image noise. It is, therefore, necessary to understand the factors that limit the detection of surface materials in evaluating temporal data. The spectral detectability of vegetation and soil in the 1990 July and October Airborne Visible/Infrared Imaging Spectrometer (AVIRIS) data of Jasper Ridge, CA was evaluated and compared