The wave numbers of supercritical surface tension driven Benard convection

The cell size or the wave numbers of supercritical hexagonal convection cells in primarily surface tension driven convection on a uniformly heated plate was studied experimentally in thermal equilibrium in thin layers of silicone oil of large aspect ratio. It was found that the cell size decreases with increased temperature difference in the slightly supercritical range, and that the cell size is unique within the experimental error. It was also observed that the cell size reaches a minimum and begins to increase at larger temperature differences. This reversal of the rate of change of the wave number with temperature difference is attributed to influences of buoyancy on the fluid motion. The consequences of buoyancy were tested with three fluid layers of different depth

Zonal analysis of two high-speed inlets

Using a zonal technique, thin layer Navier-Stokes solutions for two high speed inlet geometries are presented and compared with experimental data. The first configuration consists of a 3-D inlet preceded by a sharp flat plate. Results with two different grids demonstrate the importance of adequate grid refinement in high speed internal flow computations. The fine grid solution has reasonably good agreement with experimental heat transfer and pressure values inside the inlet. The other configuration consists of a 3-D inlet mounted on a research hypersonic forebody. Numerical results for this configuration have good agreement with experimental pressure data along the forebody, but not inside the inlet. A more refined grid calculation is currently being done to better predict the flowfield in the inlet

Primordial helium recombination III: Thomson scattering, isotope shifts, and cumulative results

Upcoming precision measurements of the temperature anisotropy of the cosmic microwave background (CMB) at high multipoles will need to be complemented by a more complete understanding of recombination, which determines the damping of anisotropies on these scales. This is the third in a series of papers describing an accurate theory of HeI and HeII recombination. Here we describe the effect of Thomson scattering, the $^3$He isotope shift, the contribution of rare decays, collisional processes, and peculiar motion. These effects are found to be negligible: Thomson and $^3$He scattering modify the free electron fraction $x_e$ at the level of several $\times 10^{-4}$. The uncertainty in the $2^3P^o-1^1S$ rate is significant, and for conservative estimates gives uncertainties in $x_e$ of order $10^{-3}$. We describe several convergence tests for the atomic level code and its inputs, derive an overall $C_\ell$ error budget, and relate shifts in $x_e(z)$ to the changes in $C_\ell$, which are at the level of 0.5% at $\ell =3000$. Finally, we summarize the main corrections developed thus far. The remaining uncertainty from known effects is $\sim 0.3$ in $x_e$.Comment: 19 pages, 15 figures, to be submitted to PR

Business in Nebraska #283 - April 1968

Nebraska Educational Expenditures (Dorothy Switzer) In terms of expenditure, education is by far the leading function of state and local government. In terms of socio-economic progress in the modern world, attainment of high educational standards is obligatory. Educational expenditures in Nebraska in comparison to other states, therefore, become a matter of extreme urgency as we attempt to build a climate conducive to economic and business growth. Business Summary (E. L. Burgess) January\u27s dollar volume of business in Nebraska (Table I) rose 10.5% from January, 1967. Nebraska\u27s physical volume for the same period rose 6.3%. This indicates a significant rise in prices during this period. The U.S. dollar volume increased 8.8% and the physical volume increased 5.2%. Nebraska\u27s December, 1967, to January, 1968, changes in dollar volume and physical volume were +4.7% and +0.9%. January, 1967, to January, 1968, changes in the individual business indicators ranged from +1.0% for construction activity to +11.2% for life insurance sales and electricity produced. How Does Your City Grow? (E. D. Solberg

A Method for Individual Source Brightness Estimation in Single- and Multi-band Data

We present a method of reliably extracting the flux of individual sources from sky maps in the presence of noise and a source population in which number counts are a steeply falling function of flux. The method is an extension of a standard Bayesian procedure in the millimeter/submillimeter literature. As in the standard method, the prior applied to source flux measurements is derived from an estimate of the source counts as a function of flux, dN/dS. The key feature of the new method is that it enables reliable extraction of properties of individual sources, which previous methods in the literature do not. We first present the method for extracting individual source fluxes from data in a single observing band, then we extend the method to multiple bands, including prior information about the spectral behavior of the source population(s). The multi-band estimation technique is particularly relevant for classifying individual sources into populations according to their spectral behavior. We find that proper treatment of the correlated prior information between observing bands is key to avoiding significant biases in estimations of multi-band fluxes and spectral behavior, biases which lead to significant numbers of misclassified sources. We test the single- and multi-band versions of the method using simulated observations with observing parameters similar to that of the South Pole Telescope data used in Vieira, et al. (2010).Comment: 11 emulateapj pages, 3 figures, revised to match published versio

Composition Profiles in Electrodeposited Ceramic Superlattices

Superlattices in the Pb-Tl-O system with layer thicknesses in the 4-6 nm range were electrodeposited from a single aqueous solution by pulsing the applied potential during deposition. The current-time transients that resulted from the potential steps were monitored to both calculate and tailor the composition profiles of the superlattices during growth. The Cottrell method was used to determine that Tl(l) oxidation was diffusion limited at high potentials. The diffusion limitation resulted in a composition profile that was graded throughout the layer with a t-1/2 dependence. Superlattices grown at lower potentials in which both reactants were under kinetic control had square composition profiles

Electronic control and switching of entangled spin state using anisotropy and exchange in the three-particle paradigm

We explore the control and switching of the entangled spin states of multi-spin particle qubit coupled to an electron using a three-particle spin model described by $S_i$ ($i=1,2,3$), in which $S_1=\tfrac{1}{2}$ is an electron and $S_{2,3}$ can have any spin with both exchange coupling and magnetic anisotropy. We derive a general formula for the existence of a switching (DJ) resonance for any spin $S_{2,3}$. We further contrast the entanglement switching mechanisms for the $S_{2,3}=\tfrac{1}{2}$ and $S_{2,3}=1$ spin models. We find that while the onsite magnetic anisotropy in the case of $S_{2,3}>\tfrac{1}{2}$ allows full control of their spin states via interaction with $S_1$, in order to achieve acceptable control of a Bloch vector within the $S_{2,3}=\tfrac{1}{2}$ model, additional mechanisms, such as anisotropic exchange coupling, are required

Written records of historical tsunamis in the northeastern South China Sea - Challenges associated with developing a new integrated database

Comprehensive analysis of 15 previously published regional databases incorporating more than 100 sources leads to a newly revised historical tsunami database for the northeastern (NE) region of the South China Sea (SCS) including Taiwan. The validity of each reported historical tsunami event listed in our database is assessed by comparing and contrasting the information and descriptions provided in the other databases. All earlier databases suffer from errors associated with inaccuracies in translation between different languages, calendars and location names. The new database contains 205 records of "events" reported to have occurred between AD 1076 and 2009. We identify and investigate 58 recorded tsunami events in the region. The validity of each event is based on the consistency and accuracy of the reports along with the relative number of individual records for that event. Of the 58 events, 23 are regarded as "valid" (confirmed) events, three are "probable" events and six are "possible". Eighteen events are considered "doubtful" and eight events "invalid". The most destructive tsunami of the 23 valid events occurred in 1867 and affected Keelung, northern Taiwan, killing at least 100 people. Inaccuracies in the historical record aside, this new database highlights the occurrence and geographical extent of several large tsunamis in the NE SCS region and allows an elementary statistical analysis of annual recurrence intervals. Based on historical records from 1951-2009 the probability of a tsunami (from any source) affecting the region in any given year is relatively high (33.4%). However, the likelihood of a tsunami that has a wave height >1 m, and/or causes fatalities and damage to infrastructure occurring in the region in any given year is low (1-2%). This work indicates the need for further research using coastal stratigraphy and inundation modeling to help validate some of the historical accounts of tsunamis as well as adequately evaluate the recurrence intervals of tsunamis along the now heavily developed coastlines of the region. © Author(s) 2010.published_or_final_versio

The Geology and Structures in the Northern Hiko Range, Lincoln County, Nevada

In the northern Hiko Range, extension occurred in four temporally distinct episodes during the Cenozoic. The extensional events are (1) prevolcanic (\u3e 27.31 ± 0. 03 Ma), (2) syn-volcanic (between 22.78 ± 0,03 and 18.5 ± 0.4 Ma), (3) Tertiary(?) post-volcanic ( \u3c 14.7 ± 0.4 Ma), and ( 4) Pliocene(?) - Quaternary. Four fault sets are delineated based on orientation and cross-cutting relationships: (I) northeast- to northwest-striking moderately dipping prevolcanic faults, (2) east-west striking, steeply-dipping syn-volcanic faults, (3) east-west- and east-northeast-striking, steeply dipping Tertiary(?) post-volcanic faults, and (4) generally north-striking steeply dipping Pliocene (?) - Quaternary faults. Prevolcanic faults in the northern Hiko Range are interpreted to be footwall faults to an Oligocene age extensional system. These faults increase the area affected by Oligocene extension and support existing evidence that suggests this event is widespread. A tectonomagmatic rift model has been proposed to explain synvolcanic extension during the Tertiary in the northern Basin and Range province. This model suggests that the mechanism for change in the horizontal principal stress direction, from north-south oriented o2 and east-west oriented o3 to east-west oriented o1 and north-south oriented o3, is temporally and spatially associated with the southward passage of a belt of volcanism. A few east-west-striking synvolcanic faults crop out in the Hiko Range and can be explained by a tectonomagmatic rift model. However, the majority of the faults are postvolcanic and are not readily explained by the tectonomagmatic rift model. Both eastwest- and east-northeast-striking oblique-slip faults occur along the Timpahute lineament. These faults are postvolcanic, but should be synvolcanic if the tectonomagmatic rift model applies. In addition, faults in the central part of the Timpahute lineament were active more than once since the Oligocene and the lineament may be related to transform and transverse faults formed during Precambrian rifting. The Hiko fault zone is a segmented fault of Pliocene (?) - Quaternary age that may still be active and is interpreted to be the bounding fault of a half graben in Pahranagat Valley. A leaky segment boundary, the Hiko segment boundary (named here), is a structural boundary interpreted to be breached by faulting along the Hiko fault zone. Segment boundaries are sites where earthquakes begin or end. Earthquakes associated with the Hiko segment boundary, segments of the Hiko fault zone, and potentially active faults in the Timpahute lineament, pose seismic hazards, such as liquefaction, ground shaking, surface rupture, and rock falls, to the community of Hiko, Nevada. The geology and the multiple generations of extensional structures exposed at the surface in the northern Hiko Range are similar to that in many of the oil fields in central Nevada. Therefore, this study may help understand complex trapping mechanisms, and thus, aid hydrocarbon exploration