Device for directionally controlling electromagnetic radiation Patent

Concentrator device for controlling direction of solar energy onto energy converter

Directional control of radiant heat

Surface with grooves having flat bases gives directional emissivities and absorptivities that can be made to approximate a perfect directional surface. Radiant energy can then be transferred in desired directions

The effects of bilingualism on speakers who stutter during late childhood

Objectives: To examine stuttering by children speaking an alternative language exclusively (LE) or with English (BIL) and to study onset of stuttering, school performance and recovery rate relative to monolingual speakers who stutter (MONO). Design: Clinical referral sample with supplementary data obtained from speech recordings and interviews. Setting: South-East England, 1999–2007. Participants: Children aged 8–12 plus who stuttered (monolingual and bilingual) and fluent bilingual controls (FB). Main outcome measures: Participants’ stuttering history, SATS scores, measures of recovery or persistence of stuttering. Results: 69 (21.8%) of 317 children were bilingual. Of 38 children who used a language other than English at home, 36 (94.7%) stuttered in both languages. Fewer LE (15/38, 39.5%) than BIL (23/38, 60.5%) children stuttered at first referral to clinic, but more children in the fluent control sample were LE (28/38, 73.7%) than BIL (10/38, 26.3%). The association between stuttering and bilingual group (LE/BIL) was significant by x2 test; BIL speakers have more chance of stuttering than LE speakers. Age at stuttering onset and male/female ratio for LE, BIL and MONO speakers were similar (4 years 9 months, 4 years 10 months and 4 years 3 months, and 4.1:1, 4.75:1 and 4.43:1, respectively). Educational achievement was not affected by bilingualism relative to the MONO and FB groups. The recovery rate for the LE and MONO controls together (55%) was significantly higher by x2 test than for the BIL group (25%). Conclusions: BIL children had an increased risk of stuttering and a lower chance of recovery from stuttering than LE and MONO speakers

Measurement of the elastic scattering cross section of neutrons from argon and neon

Background: The most significant source of background in direct dark matter searches are neutrons that scatter elastically from nuclei in the detector's sensitive volume. Experimental data for the elastic scattering cross section of neutrons from argon and neon, which are target materials of interest to the dark matter community, were previously unavailable. Purpose: Measure the differential cross section for elastic scattering of neutrons from argon and neon in the energy range relevant to backgrounds from (alpha,n) reactions in direct dark matter searches. Method: Cross-section data were taken at the Triangle Universities Nuclear Laboratory (TUNL) using the neutron time-of-flight technique. These data were fit using the spherical optical model. Results: The differential cross section for elastic scatting of neutrons from neon at 5.0 and 8.0 MeV and argon at 6.0 MeV was measured. Optical-model parameters for the elastic scattering reactions were determined from the best fit to these data. The total elastic scattering cross section for neon was found to differ by 6% at 5.0 MeV and 13% at 8.0 MeV from global optical-model predictions. Compared to a local optical-model for 40Ar, the elastic scattering cross section was found to differ from the data by 8% at 6.0 MeV. Conclusions: These new data are important for improving Monte-Carlo simulations and background estimates for direct dark matter searches and for benchmarking optical models of neutron elastic scattering from these nuclei

A theoretical model for single molecule incoherent scanning tunneling spectroscopy

Single molecule scanning tunneling spectroscopy (STS), with dephasing due to elastic and inelastic scattering, is of some current interest. Motivated by this, we report an extended Huckel theory (EHT) based mean-field Non-equilibrium Green's function (NEGF) transport model with electron-phonon scattering treated within the self-consistent Born approximation (SCBA). Furthermore, a procedure based on EHT basis set modification is described. We use this model to study the effect of the temperature dependent dephasing, due to low lying modes in far-infrared range for which hw<<kT, on the resonant conduction through highest occupied molecular orbital (HOMO) level of a phenyl dithiol molecule sandwiched between two fcc-Au(111) contacts. Furthermore, we propose to include dephasing in room temperature molecular resonant conduction calculations.Comment: 12 pages, 5 figure

Long term time-lapse microgravity and geotechnical monitoring of relict salt-mines, Marston, Cheshire, UK.

The area around the town of Northwich in Cheshire, U. K., has a long history of catastrophic ground subsidence caused by a combination of natural dissolution and collapsing abandoned mine workings within the underlying Triassic halite bedrock geology. In the village of Marston, the Trent and Mersey Canal crosses several abandoned salt mine workings and previously subsiding areas, the canal being breached by a catastrophic subsidence event in 1953. This canal section is the focus of a long-term monitoring study by conventional geotechnical topographic and microgravity surveys. Results of 20 years of topographic time-lapse surveys indicate specific areas of local subsidence that could not be predicted by available site and mine abandonment plan and shaft data. Subsidence has subsequently necessitated four phases of temporary canal bank remediation. Ten years of microgravity time-lapse data have recorded major deepening negative anomalies in specific sections that correlate with topographic data. Gravity 2D modeling using available site data found upwardly propagating voids, and associated collapse material produced a good match with observed microgravity data. Intrusive investigations have confirmed a void at the major anomaly. The advantages of undertaking such long-term studies for near-surface geophysicists, geotechnical engineers, and researchers working in other application areas are discussed

CCD photometry of 2060 Chiron, 1991 January

Observations of 2060 Chiron was performed on 7 to 8 Jan. 1991 with the Mt. Palomar 1.52 m telescope in the Gunn-R passband. On-chip field stars were used to perform differential reductions. The repeatability of the 5.9 hour light curve was excellent, both within a night and from night to night. No evidence for short-term secular variations similar to those seen last year by both Luu and Jewitt (1990) and Buratti and Dunbar (1991) is seen in the new light curve. Chiron's rotational light curve appears strikingly similar to that obtained a year earlier by Luu and Jewitt (1990), both in amplitude and shape. Both light curves show strongly correlated changes over a timescale of perhaps 15 minutes. These same features were marginally visible in the 1986 light curve. Such behavior is believed to be evidence that Chiron may be more aspherical than the 4 percent intensity variation might otherwise indicate, and favors a viewing geometry where the subearth latitude is rather low. Chiron was much fainter in 1985, when a partial light curve was obtained by Marcialis. Due to the lower sampling rate of these early data, no conclusions can be made regarding the high-frequency light curve structure back then. All three of these light curves differ significantly from that obtained by Buratti and Dunbar (1991), one week before the observations of Luu and Jewitt. The Chiron field was calibrated using Landolt standards on Ut 15 Mar. 1991. A mean R-magnitude of 15.6 + or - 0.1 was found. Variability of 2060 Chiron was demonstrated over timescales of minutes, hours, and years. An intense campaign was urged to monitor the photometric behavior of Chiron throughout the 1990s