Ternary thin film alloys of Se90-XIn10SbX (x = 1, 4, 10, 15 and 20) were synthesised by flash evaporation of the pre-melt quenched bulk samples under a vacuum of 10(-5) Torr. Optical absorption analysis pointed to indirect allowed transitions as the mechanism of excitation across the energy gap. The optical band gap (E-g) was evaluated on the basis of Wemple-Didomenico single oscillator model and Tauc's extrapolation method in the spectral region where the absorption coefficient, alpha >= 10(4) cm(-1). The refractive index (n), complex dielectric constant (epsilon), band tailing parameter (B), plasma frequency (omega(p)), single oscillator parameters (E-o and E-d) and lattice dielectric constant (epsilon(L)) were deduced for each alloy. The compositional dependence of optical and dielectric parameters was explained on the basis of chemical bond approach. The observed shift in the trends of E-g, E-d, epsilon(L) and omega(p) values at the composition where Sb = 4 at% was correlated to the usual chemical threshold at this composition. (C) 2016 Elsevier B.V. All rights reserved.

Rock‐magnetic and Thellier‐Thellier‐Coe paleointensity results are reported for a new collection of samples from the 2.78 Ga Modipe Gabbro of Botswana. The magnetic properties are very favorable, leading to an unusually high success rate and a well‐constrained result of 36–40 µT (95% confidence interval). We discuss the long‐standing problem of allowing for the enormous differences between the natural and laboratory cooling rates, and apply a temperature‐dependent correction derived from first‐order reversal curve (FORC) data. Whereas pure single‐domain (SD) corrections often lead to quite large decreases in paleointensity estimates (sometimes exceeding 50%), we find a modest increase of about 10%. The Earth's Magnetic Dipole moment in the late Archaean is thereby estimated to have been ∼6×1022 Am2.

Studies on radon monitoring are essential for countries actively involved in mining activities. Since large-scale mining activities have the potential to enhance the background radiation levels, a detailed study on indoor and outdoor radon levels, its diurnal variation with temperature, pressure and humidity for Botswana is initiated. The study is important because such studies for Botswana are non-existent and the database on indoor and outdoor 222Rn concentration and the resulting inhalation dose to the population of the region is not available. Measurements were carried out using the AlphaGuard (Genitron,Germany) Professional Radon Monitor. The concentration of 226Ra in soil was also measured by gamma spectrometry using a 41% relative efficiency n-type HPGe detector (Canberra, USA). Initial results show that the indoor 222Rn concentration vary in the range 3.0–93.0Bqm−3 with a mean of 24.5Bqm−3. Diurnal variation studies show that the concentration is higher in the early morning hours and lower in the early afternoon hours. All the results are presented and discussed in detail in this paper.

Although several studies have recommended removal ofsecondary components of magnetic remanence by zero-field cycling from room temperature o a temperature much lower than the low temperature transition for magnetite (about 120 K), the method has not become a standard outine technique. This is partly due to the poor understanding of the behavior f magnetite particles at the low-temperature transition zone. Previous experiments by other researchers ave used magnetite powders. In such powders it is always possible to attribute any discrepancy between the results observed and theory to possible existence of magnetostatic interaction effects orexistence of longated particles in amples presumed to contain only equant particles. Such factors need to be eliminated in order to have abetter understanding of the low temperature behavior fmagnetite particles. Low-temperature magnetic properties of lithographically produced arrays of both interacting and noninteracting cubic magnetite particles a well as those from powder particles have been measured as part of this study. Agradual increase in the amount ofsaturation isothermal remanent magnetization (SIRM) lost at the Verwey transition T v with increasing particle size in the pseudo-single-domain size r nge has been observed. This behavior is consistent with the vortex state domain structure. The grain size dependence of the amount of SIRM lost at T v is most probably what previous re earchers reported as amagnetic memory particle-sizedependent trend. Magnetic memory measured during the cooling and warming process i shown to be a stress-related phenomenon. Such measurements could be useful in assessing the nature of stress in a magnetite sample.

The magnetic hysteresis properties for well‐defined micron‐sized magnetite samples produced by electron beam lithography (EBL) are presented. In addition to measuring standard hysteresis parameters, first‐order reversal curve (FORC) diagrams are also reported. EBL produces samples that consist of particles with very tightly constrained size distributions, and spatial distributions that govern the degree of intergrain magnetostatic interactions are accurately controlled and known. Thus EBL samples are significantly better characterized compared to powdered samples, which are conventionally used to characterize the size dependency of magnetic hysteresis properties of naturally occurring magnetic minerals. Compared with the hysteresis properties of powdered samples of the same nominal sizes, EBL samples display more multidomain‐like (MD) behavior. The influence of magnetostatic interactions fields on hysteresis properties is analyzed. When magnetostatic interactions are effectively in only one direction, the hysteresis properties become more single domain‐like, and if the interactions are in more than one direction, hysteresis becomes more MD‐like, in agreement with numerical models.

First‐order reversal curve (FORC) diagrams for mixtures of different magnetic phases and bimodal distributions have been measured to examine the efficiency of the FORC method at unraveling complex magnetic signals. The FORC distributions for various magnetic minerals, including magnetite, maghemite, hematite, and goethite, and their linear additivity are assessed. Mixtures containing only hard magnetic minerals like hematite or goethite, which have relatively small spontaneous magnetizations (MS) and large magnetocrystalline anisotropies, can be adequately described by a linear addition of the two end‐members, because there are virtually no magnetostatic interactions between the phases. Mixtures dominated by softer minerals like magnetite and maghemite are more susceptible to interactions and exhibit nonlinear behavior. When a hard phase with low MS like hematite is mixed with a softer phase with high MS like magnetite, it can still be identified using the FORC technique, whereas it is impossible to do so using standard magnetic hysteresis measurements. When the weaker phase can be identified, then weak‐strong mixes add linearly; however, beyond a certain critical concentration the mineral with high MS swamps the magnetic signal and linearity breaks down. It is suggested that the FORC method is highly suitable for identifying small traces of hard magnetic minerals like hematite and goethite in the presence of minerals with high MS such as magnetite.

Solar radiation parameters and mean monthly optimum slopes are studied experimentally and theoretically at 10 different locations of Botswana. It is found that throughout Botswana all mean yearly daily solar radiation components are extremely high. Mean monthly optimum slopes are negative (collector should face North) in June and positive (collector should face South) in December.It was also observed that the UV-component during the last 8 years has increased by about 5 to 7%. It was also found that the filter used in the instrumentation for UV-radiation measurements is slowly degrading, and hence calibration should be done at least every six months of the year.Cases of anomalous phenomena when direct normal radiation is increasing greatly (and diffuse radiation decreasing) after solar noon, are observed and discussed. It is also found that when humidity is low and visibility is high, hourly I-g-values recorded with a pyranometer can be less than (I-b & Unknown; cos2(z) +I-d) values. This discrepancy, which could be quite common for regions with desert conditions (low humidity and turbidity) is discussed and explained.

Color Research & ApplicationVolume 27, Issue 6 p. 461-463 Miscellaneous ISCC/DCC symposium: Color/Design Tech II James G. King, James G. King DuPont Performance CoatingsSearch for more papers by this authorRuth B. Theobald, Ruth B. Theobald DuPont Performance CoatingsSearch for more papers by this author James G. King, James G. King DuPont Performance CoatingsSearch for more papers by this authorRuth B. Theobald, Ruth B. Theobald DuPont Performance CoatingsSearch for more papers by this author First published: 23 October 2002 https://doi.org/10.1002/col.10104AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinked InRedditWechat Volume27, Issue6December 2002Pages 461-463 RelatedInformation

Although several studies have recommended removal of secondary components of magnetic remanence by zero‐field cycling from room temperature to a temperature much lower than the low temperature transition for magnetite (about 120 K), the method has not become a standard routine technique. This is partly due to the poor understanding of the behavior of magnetite particles at the low‐temperature transition zone. Previous experiments by other researchers have used magnetite powders. In such powders it is always possible to attribute any discrepancy between the results observed and theory to possible existence of magnetostatic interaction effects or existence of elongated particles in samples presumed to contain only equant particles. Such factors need to be eliminated in order to have a better understanding of the low temperature behavior of magnetite particles. Low‐temperature magnetic properties of lithographically produced arrays of both interacting and noninteracting cubic magnetite particles as well as those from powder particles have been measured as part of this study. A gradual increase in the amount of saturation isothermal rémanent magnetization (SIRM) lost at the Verwey transition Tv with increasing particle size in the pseudo‐single‐domain size range has been observed. This behavior is consistent with the vortex state domain structure. The grain size dependence of the amount of SIRM lost at Tv is most probably what previous researchers reported as a magnetic memory particle‐size‐dependent trend. Magnetic memory measured during the cooling and warming process is shown to be a stress‐related phenomenon. Such measurements could be useful in assessing the nature of stress in a magnetite sample.

Unilateral injection of tetrodotoxin or cadmium chloride into the frog optic nerve selectively eliminates behavioral responses to looming stimuli while sparing responses to prey stimuli. This behavioral loss is correlated with a loss of activity of "dimming" units in tectal layer G. These findings suggest that separate sets of retinal ganglion cell fibers carry information concerning looming stimuli and prey stimuli. The lack of activity in layer G suggests that information about looming stimuli is being conveyed by myelinated retinal ganglion cell axons. It is argued that unmyelinated fibers are not blocked by the neurotoxins because the extracellular space around the fibers is mostly inaccessible.

Bird migration was monitored for 4 years (1987 to 1990), at 2 central Alaska lo- cations proposed for huge Air Force radar screens. Nearly 10,000 flocks of large birds were re- corded; 30% of these flocks included swans. Approximately 7% (n = 211) of these swan flocks were composed of 2 or more species. Mixed flocks of tundra swans (Cygnus columbianus) and trumpeter swans (C. buccinator) were recorded most often (103 flocks). Swan flocks also con- tained geese (80 flocks) and ducks (16 flocks). Swans also were observed migrating with sandhill cranes (Grus canadensis, 3 flocks) and large gulls (Larus spp., 2 flocks). Mixed flocks always were flying in the long line formations typical of swans in migration and were intermixed rather than grouped. Only in the case of cranes were the swans outnumbered by other species.

Arrays of magnetite particles in the submicron range (0.1–4.0 µm) have been produced. A novel method involving the utilisation of Electron Beam Lithography techniques often employed in the engineering design of integrated circuits of microchips was used. The fabrication process involved first producing arrays of iron (Fe) particles and then converting them to magnetite (Fe3O4) by thermal treatment. The fabricated magnetite particles have well controlled parameters including inter‐particle spacing, an impossible task to achieve using artificially produced powders often employed in rockmagnetic studies. Two methods of converting Fe to Fe3O4 by annealing were used. One method led to Fe3O4 grains with high coercivities, typical of stressed grains and the other low coercivities in agreement with those for laboratory grown crystals. The crystal unit cell edge. Curie temperature, and saturation isothermal remanent magnetisation (SIRM) intensity observed at the Verwey transition are all consistent with stoichiometric magnetite.

Fire fighting equipment is predominantly red or red/white. However, this study reports that if other factors are the same, the probability of a visibility-related accident for a red or red/white pumper is greater than the probability for a lime-yellow/white pumper. Data from public safety departments' records regarding fire pumper runs and accidents that occurred over a four year period in a single city are reviewed and tabulated. It is shown that lime-yellow/white fire pumpers are significantly statistically safer than red and red/white fire pumpers.

A low molecular weight endogenous substance believed to be responsible for extracellular fluid homeostasis in mammals has been sought for many years. Our goal is to isolate and structurally characterize this putative “natriuretic hormone”. We have developed an assay using the conscious rat to measure prolonged natriuresis (Benaksas et al (1993) Life Sciences, 52, 1045–1054), the activity originally described for this putative substance. Using this assay we have identified a number of natriuretic compounds isolated from human uremic urine. The collected urine is processed by ultrafiltration (≤ 3 kDa), gel filtration chromatography (G-25) and extraction with isopropanol and diethyl ether. The organic soluble material is then subjected to sequential high-performance liquid chromatography. We report here the initial characterization of two pure isolates (LLU-α and LLU-γ) obtained by this method, and the structural elucidation of a third pure compound, LLU-β1, a natriuretic and previously unreported metabolite of the drug diltiazem.

Color Research & ApplicationVolume 17, Issue 1 p. 69-70 Miscellaneous ISCC 1991 annual meeting James G. King, James G. King E. I. Du Pont de Nemours & Co., Inc. Troy Research and Development Laboratory 945 Stephenson Highway Troy, Michigan 48007-2802Search for more papers by this author James G. King, James G. King E. I. Du Pont de Nemours & Co., Inc. Troy Research and Development Laboratory 945 Stephenson Highway Troy, Michigan 48007-2802Search for more papers by this author First published: February 1992 https://doi.org/10.1002/col.5080170117AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinked InRedditWechat No abstract is available for this article. Volume17, Issue1February 1992Pages 69-70 RelatedInformation