Supersonic axial-force characteristics of a rectangular-box cavity with various length-to-depth ratios in a flat plate

A wind-tunnel investigation has been conducted at Mach numbers of 1.50, 2.16, and 2.86 to obtain axial-force data on a metric rectangular-box cavity with various length-to-depth ratios. The model was tested at angles of attack from -4 deg to -2 deg. The results are summarized to show variations in cavity axial-force coefficient for deep- and shallow-cavity configurations with detached and attached cavity flow fields, respectively. The results of the investigation indicate that for a wide range of cavity lengths and depths, good correlations of the cavity axial-force coefficients (based on cavity rear-face area) are obtained when these coefficients are plotted as a function of cavity length-to-depth ratio. Abrupt increases in the cavity axial-force coefficients at an angle of attack of 0 deg. reflect the transition from an open (detached) cavity flow field to a closed (attached) cavity flow field. Cavity length-to-depth ratio is the dominant factor affecting the switching of the cavity flow field from one type to the other. The type of cavity flow field (open or closed) is not dependent on the test angles of attack except near the critical value of length-to-depth ratio

How can we test seesaw experimentally?

The seesaw mechanism for the small neutrino mass has been a popular paradigm, yet it has been believed that there is no way to test it experimentally. We present a conceivable outcome from future experiments that would convince us of the seesaw mechanism. It would involve a variety of data from LHC, ILC, cosmology, underground, and low-energy flavor violation experiments to establish the case.Comment: 5 pages, 4 figure

Phenology satellite experiment

The detection of a phenological event (the brown wave-vegetation senescence) for specific forest and crop types using ERTS-1 imagery is described. Data handling techniques included computer analysis and photo interpretation procedures. Computer analysis of ERTS-1 multispectral scanner digital tapes in all bands was used to give the relative changes of spectral reflectance with time of forests and specified crops. These data were obtained for a number of the study's twenty-four sites located within four north-south corridors across the United States. Analysis of ground observation photography and ERTS-1 imagery for sites in the Appalachian Corridor and Mississippi Valley Corridor indicates that the recession of vegetation development can be detected very well. Tentative conclusions are that specific phenological events such as crop maturity or leaf fall can be mapped for specific sites and possibly for entire regions

Improvement of the Nutritive Value of High Tannin Sorghums for Broiler Chickens by High Moisture Storage (Reconstitution)

Grains from three high and one low tannin sorghum cultivars were treated as follows: 1) untreated, no water was added, the dry grain had an average moisture content of 8% and 2) the moisture content of the grain was raised by adding 25% (w/w) distilled water to the grain. The treated grain was then stored for 10 or 20 days with a 2% level of acetic-propionic acid mixture (60/40, v/v) added to deter fungal growth. This treated grain was used in diets during a 3-week feeding trial with broiler chickens. High moisture storage (reconstitution) of high tannin sorghums decreased their extractable tannin content. Chickens fed diets containing these treated sorghums had improved weight grains (23 to 83 g) and feed efficiencies compared to birds fed diets containing the untreated grain. Treatment of low tannin sorghum did not improve weight gains. Reconstitution of high but not low tannin sorghums improved protein digestibility (6 to 16%) and dietary metabolizable energy (.1 to .3 kcal/g) for broiler chickens. There was a highly significant cultivar effect on leg scores, but the correlation between dietary tannin content and leg scores was low (r = .10), suggesting that tannin content was not a major factor in leg abnormality incidences shown. The improvement in weight grains, feed efficiencies, and protein digestibilities at 10 and 20 days storage periods was not different (P greater than .05), indicating that the benefits of high moisture storage were already obtained by 10 days

Evaluation of a technique to generate artificially thickened boundary layers in supersonic and hypersonic flows

The feasibility of using a contoured honeycomb model to generate a thick boundary layer in high-speed, compressible flow was investigated. The contour of the honeycomb was tailored to selectively remove momentum in a minimum of streamwise distance to create an artificially thickened turbulent boundary layer. Three wind tunnel experiments were conducted to verify the concept. Results indicate that this technique is a viable concept, especially for high-speed inlet testing applications. In addition, the compactness of the honeycomb boundary layer simulator allows relatively easy integration into existing wind tunnel model hardware

Specifying ODP computational objects in Z

The computational viewpoint contained within the Reference Model of Open Distributed Processing (RM-ODP) shows how collections of objects can be configured within a distributed system to enable interworking. It prescribes certain capabilities that such objects are expected to possess and structuring rules that apply to how these objects can be configured with one another. This paper highlights how the specification language Z can be used to formalise these capabilities and the associated structuring rules, thereby enabling specifications of ODP systems from the computational viewpoint to be achieved

Search for bursts in air shower data

There have been reports in recent years of the possible observation of bursts in air shower data. If such events are truly of an astrophysical nature then, they represent an important new class of phemonenon since no other bursts have been observed above the MeV level. The spectra of conventional gamma ray bursts are unknown at higher energies but their observed spectra at MeV energies appear generally to exhibit a steepening in the higher MeV range and are thus unlikely to extrapolate to measurable fluxes at air shower energies. An attempt has been made to look for deviations from randomness in the arrival times of air showers above approx. 10 to the 14th power eV with a number of systems and results so far are presented here. This work will be continued for a substantial period of ime with a system capable of recording bursts with multiple events down to a spacing of 4 microns. Earlier data have also been searched for the possible association of air shower events with a glitch of the Vela pulsar

Phenology satellite experiment

There are no author-identified significant results in this report

The Relationship Between Galaxies and Low Redshift Weak Lyman alpha Absorbers in the Directions of H1821+643 and PG1116+215

To study the nature of low z Lya absorbers in the spectra of QSOs, we have obtained high signal-to-noise UV spectra of H 1821+643 (z = 0.297) and PG 1116+215 (z = 0.177) with the GHRS on the HST. The spectra have minimum S/N of 70-100 and 3 sigma limiting equivalent widths of 50-75 mA. We detect 26 Lya lines with Wr > 50 mA toward H1821+643 and 13 toward PG1116+215, which implies a density of 102+/-16 lines per unit redshift. The two-point correlation function shows marginal evidence of clustering on ~500 km/s scales, but only if the weakest lines are excluded. We have also used the WIYN Observatory to measure galaxy redshifts in the ~1 degree fields centered on each QSO. We find 17 galaxy-absorber pairs within projected distances of 1 Mpc with velocity separations of 350 km/s or less. Monte Carlo simulations show that if the Lya lines are randomly distributed, the probability of observing this many close pairs is 3.6e-5. We find that all galaxies with projected distances of 600 kpc or less have associated Lya absorbers within 1000 km/s, and the majority of these galaxies have absorbers within 350 km/s. We also find that the Lya equivalent width is anticorrelated with the projected distance of the nearest galaxy out to at least 600 kpc, but this should be interpreted cautiously because there are potential selection biases. Statistical tests using the entire sample also indicate that the absorbers are not randomly distributed. We discuss the nature of the Lya absorbers in light of the new data.Comment: Accepted for publication in ApJ. 17 pages plus 11 tables and 17 figure

Physical Properties and Baryonic Content of Low-Redshift Intergalactic Ly-alpha and O VI Absorption Systems: The PG1116+215 Sight Line

We present HST and FUSE observations of the intergalactic absorption toward PG1116+215 in the 900-3000 A spectral region. We detect 25 Ly-alpha absorbers at rest-frame equivalent widths W_r > 30 mA, yielding (dN/dz)_Ly-alpha = 154+/-18 over an unblocked redshift path of 0.162. Two additional weak Ly-alpha absorbers with W_r ~ 15-20 mA are also present. Eight of the Ly-alpha absorbers have large line widths (b > 40 km/sec). The detection of narrow OVI in the broad Ly-alpha absorber at z=0.06244 supports the idea that the Ly-alpha profile is thermally broadened in gas with T > 10^5 K. We find dN/dz ~ 50 for broad Ly-alpha absorbers with W_r > 30 mA and b > 40 km/sec. If the broad Ly-alpha lines are dominated by thermal broadening in hot gas, the amount of baryonic material in these absorbers is enormous, perhaps as much as half the baryonic mass in the low-redshift universe. We detect OVI absorption in several of the Ly-alpha clouds along the sight line. Two detections at z=0.13847 and z=0.16548 are confirmed by the presence of other ions at these redshifts, while the detections at z=0.04125, 0.05895, 0.05928, and 0.06244 are based upon the Ly-alpha and OVI detections alone. The information available for 13 low-redshift OVI absorbers with W_r > 50 mA along 5 sight lines yields (dN/dz)_OVI ~ 14 and Omega_b(OVI) > 0.0027/h_75, assuming a metallicity of 0.1 solar and an OVI ionization fraction < 0.2. The properties and prevalence of low-redshift OVI absorbers suggest that they too may be a substantial baryon repository, perhaps containing as much mass as stars and gas inside galaxies. The redshifts of the OVI absorbers are highly correlated with the redshifts of galaxies along the sight line, though few of the absorbers lie closer than 600/h_75 kpc to any single galaxy. [abbreviated]Comment: 99 pages, 30 figures, aastex format, ApJS in pres