Surface-sediment dynamics in a dust source from spaceborne multispectral thermal infrared data

This study utilized spaceborne multispectral thermal infrared (TIR) data to document spatial relationships of surface sediments over time in a modern depositional environment associated with dust emissions, Soda Lake playa, Mojave Desert, United States. The approach employed here involved time-series TIR data acquired from Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) and a linear spectral mixture analysis. An automated algorithm was applied to derive emissivity image endmembers. Evaluation of the chosen endmembers revealed that they can be categorized into five major spectra classes based on diagnostic absorption features. Each spectrum has been identified in relation to mineral abundance and soil arrangement that are common in playa settings: A, “clayey silt-rich crust”; B, “intermediate-salt crust”; C, “quartz-rich deposit”; D, “salt-rich rough crust”; E, “sulfate-rich crust”. Spectral classes A-B-C-D yielded the lowest RMS errors (0-0.025) over time in the iterative deconvolution algorithm between the measured and modeled spectra. The produced fractional abundance images show high areal concentrations for clayey silt-rich crust, salt-rich rough crust, and quartz-rich deposit, as the first surficial mapping of Soda Lake. Significant changes in the spatial relationships of the major surface sediments in Soda Lake were observed after a flooding event (2005) and a relatively dry period (2006). The approach utilized in this study can be advantageous for continuous monitoring of environments characterized by a small area and a complex surface, which may enable a better understanding of their responses to climate changes and potential for dust emissions.     

The stress corrosion cracking of welded austenitic stainless steels in MgCl2 solutions in the presence of NaI additions

The influence of Nal additions on the stress corrosion cracking (SCC) of Type 304L and 316L welded stainless steels in 42 wt% aqueous MgCl₂ solution at 154°C has been investigated. The results indicate clearly that addition of 1 N NaI to the boiling MgCl₂ solution prevents SCC of the welded steels. The I⁻ can act as an effective cathodic inhibitor. The correlation between mechanical properties, fracture morphology and the mechanism of the inhibition behaviour of I⁻ on SCC is discussed.     

The effects of physical fitness and feeling vigorous on self-rated health.

Objective: We prospectively studied the hypothesized beneficial effects of feeling vigorous and of objective physical fitness (gauged based on functional capacity) on subsequently assessed self-rated health (SRH), controlling for possible confounders known to be precursors of SRH and of our predictors. We also investigated the reverse-causation hypothesis that SRH predicts subsequent vigor and functional capacity. Design: Participants were apparently healthy employees (N = 779) who underwent a routine health check at two points of time, Time 1 (T1) and Time 2 (T2), about 18 months apart. We used regression analysis, predicting T2 SRH by T1 SRH, the control variables, and T1vigor and functional capacity. Main Outcome Measures: Vigor was assessed using the Shirom-Melamed Vigor Measure; objective physical fitness was indicated by functional capacity following a treadmill exercise, and self-rated health was measured by a single item. Results: As hypothesized, we found that the change in T2 SRH was positively predicted by T1 vigor, functional capacity, and their interactive term. Testing the reverse causation paths, we found that T1 SRH did not predict subsequent functional capacity and was a relatively weak predictor of subsequent vigor. Conclusion: The affective state of vigor and objectively assessed functional capacity interact to predict subsequent changes in self-rated health. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

VX fate on common matrices: evaporation versus degradation

A study of the volatilization rate of the nerve agent VX (O-ethyl S-2-(N,N-diisopropylamino)ethyl methylphosphonothiolate) from various urban matrices in a specially designed climatic chamber (model system) is described. The performance of the model system combined with the analytical procedure produced profiles of vapor concentration obtained from samples of VX dispersed as small droplets on the surfaces of the matrices. The results indicated that the bitumen-containing surfaces such as asphalt blocks and bitumen sheets conserve VX and slow-release part of it over a long period of time. No complete mass balance could be obtained for these surfaces. Influence of environmental and experimental parameters as well as the efficacy of decontamination procedure were also measured. From smooth surface tiles a fast release of VX was measured and almost a complete mass balance was obtained, which characterizes the behavior of inert surfaces. Experiments carried out on concrete blocks showed fast decay of the concentration profile along with a very poor reconstruction of the initial quantity of VX, implying that this matrix degraded VX actively due to its multiple basic catalytic sites. To complement this study, solid-state NMR measurements were compared to add data concerning agent-fate within the matrices.     

The influence of alkali-halide additions on the stress corrosion cracking of an austenitic stainless steel in MgCl2 solution

The influence of NaCl, NaBr, NaI additions on the stress corrosion cracking (s.c.c.) of Type 304 stainless steel in 38 wt% aqueous MgCl₂ solution at 135°C has been investigated. Slow strainrate and U-Bend tests, potentiodynamic measurements and fractographic observation were employed. The results indicate clearly that the addition of 1N NaI or NaBr to the boiling MgCl₂ solution prevents stress corrosion cracking of the steel while NaCl additions accelerates cracking. It is suggested that the addition of NaI inhibits mainly the cathodic process. The I^? ion is oxidized by the dissolved oxygen through the following reaction: 41^? + 4H⁺ + O₂ → 2I₂ + 2H₂O.Due to this reaction O₂ and H⁺ are not reacted cathodically with the metal. This process enhanced the cathodic inhibition effect and results in preventing s.c.c. of the AISI 304 stainless steel in 38 wt% MgCl₂ boiling solution.     

A discriminant rule for screening cases of diverse diagnostic types: Preliminary results.

To assess the prevalence of specific types of mental disorders in the general community, it is desirable on grounds of both economy and validity of classification to employ a 2-stage strategy: a screening questionnaire administered by nonclinicians and a detailed diagnostic assessment by a clinician. In the present study, a 1st-stage screening rule was developed to identify persons with 1 of 4 disorders: schizophrenia, affective disorders, nonaffective neurotic disorders, and antisocial personality. The screen employed the psychiatric epidemiology research interview developed by the 2nd author and colleagues (1980). Logistic regression was used as the discriminant function model. The sample used to develop the discriminant rule consisted of 190 Israeli psychiatric inpatients (aged 20–59 yrs) and 184 Jerusalem residents judged to be well by mental health professionals. The use of 7 symptom scales correctly classified 94% of the patients and identified 84% of the community Ss as noncases. (25 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Pitting corrosion evaluation by computer image processing

Pitting corrosion of AISI 304L stainless steel in a solution of FeCl₃ is evaluated by computer image processing methods. Pitting probability and histograms of pit-areas are computed. Pitting probability is defined as the ratio of pitted area over the total area. The pitting probability in this work was found to be 9.73%. Computer image processing is shown to be a promising tool for statistical evaluation of pitting corrosion.     

Determinants of management styles in business and nonbusiness organizations.

B. M. Bass and E. R. Valenzi (1974) postulated that power and information are major factors in determining the extent to which 5 leadership styles are used and presented a set of hypotheses concerning the way power and information affect these styles. Management Styles Survey data from 224 Israeli executives were used to test the Bass-Valenzi hypothesis and to analyze the effects of aggregating data from business and nonbusiness organizations (BOs and NBOs). In BOs, direction and power were positively correlated, and in NBOs they were negatively correlated. When data from both types of organizations were aggregated, no correlation was found between power and direction. The methodological aspects of using aggregate data in tests of the Bass-Balenzi hypotheses, including regression and smallest space analysis, are discussed. It is shown that such procedures may cause aggregation bias, and it is suggested that the Bass-Valenzi hypotheses are more applicable to BOs than to NBOs. Ss from NBOs tended to employ more of the direction style and less of the participation style of leadership than executives in BOs. The results, however, also indicate that interorganizational differences in styles are mainly attributable to differences in organizational norms, climate, and structure, and not to differences in power and information. (13 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)