Search results for "Horizon"
showing 10 items of 600 documents
Superintendent Leadership in Hierarchy and Network
2015
School superintendents are coupled hierarchically with the top apex of municipality organization through their membership of leadership teams and through personal ties to the top municipal manager, which provides opportunities to take part in strategic decision-making processes beyond the educational sector. Superintendents are also vertically linked to their school leaders through strong and dense network ties. Along the horizontal axis superintendents are active network players with peers, for example through superintendent associations or more frequently mentioned through personal ties to superintendent colleagues. Superintendents are linked to school boards through strong formal ties. I…
Impedance and admittance characteristics of Bi2S3 nanowire arrays
2013
Current studies of the electrical impedance and admittance characteristics of the anodised aluminum oxide (AAO) nanoporous arrays and bismuth sulphide (Bi2S3) nanowire within AAO membranes are presented. The influence of potential and frequency scan rate effect produced on the real, imaginary and complex electrochemical impedance and double layer capacitance of the AAO nanopore and the Bi2S3 nanowire arrays were studied.
Measured and Calculated Oxidation Potentials of 1-X-12-Y-CB11Me10– Anions
2012
Cyclic voltammetry of 31 icosahedral carborane anions 1-X-12-Y-CB(11)Me(10)(-) at a Pt electrode in liquid SO(2) revealed a completely reversible one-electron oxidation even at low scan rates, except for the anions with Y = I, which are oxidized irreversibly up to a scan rate of 5.0 V/s, and the anion with X = COOH and Y = H, whose oxidation is irreversible at scan rates below 1.0 V/s. Relative reversible oxidation potentials agree well with RI-B3LYP/TZVPP,COSMO and significantly less well with RI-BP86/TZVPP,COSMO or RI-HF/TZVPP,COSMO calculated adiabatic electron detachment energies. Correlations with HOMO energies of the anions are nearly as good, even though the oxidized forms are subjec…
Oxygen-deficient Co3O4 submicron porous sphere films as highly active supsercapacitor electrodes
2021
Abstract Herein, we report Co3O4 films with different content of oxygen vacancies and shapes of particles for supercapacitor electrodes. Under the similar area ratio of OII peak in the XPS spectrum of oxygen elements, the specific capacitance of electrode films with hollow spongy-like particles (963 F/g under a scan rate of 5 mV/s) is 1.6 times higher than that of the electrodes with solid irregular particles (596 F/g), indicating the effect of particle shapes on electrochemical properties. The films composed of submicron porous spheres and containing highest content of oxygen vacancies exhibited the specific capacitances as high as 1700 F/g under the scan rate of 5 mV/s. By contrast, after…
Ecohydrological adaptation of soils following land abandonment in a semi-arid environment
2010
Representative land use types were selected in southeast Spain to investigate the redistribution of soil water in relation to vegetation development and land abandonment.Simulated rainfall experiments were performed during 2 days on each of the four selected surfaces: ploughed, a 3-year fallow field, a 12-year abandoned field with shrubs and a semi-natural field with Stipa tenacissima tussocks. Each experiment consisted of five runs of artificial rain. Soil moisture dynamics were measured by time domain reflectometry (TDR), as well as runoff and ponding on the plot surface. Also the movement of the wetting front was measured after each run.On the ploughed field, ponding and local runoff wer…
Runoff generation, sediment movement and soil water behaviour on calcareous (limestone) slopes of some Mediterranean environments in southeast Spain
2003
Abstract An interpretation of soil hydrology and erosion data obtained from limestone areas in southeast Spain is presented in the framework of recent hypotheses on runoff generation mechanisms in Mediterranean environments. The main objective is to synthesise and harmonise the data in theoretical concepts or behavioural models of hydrological functioning of Mediterranean limestone slopes. For this purpose, data were collected in a typical limestone area, with climatic characteristics ranging from subhumid to semiarid. Several sites were chosen with comparable slopes, vegetation and soils along a transect of 20 km to carry out several research projects. The data discussed in this paper cons…
Properties and erosional response of soils in a degraded ecosystem in Crete (Greece)
2013
To study desertification processes relating to soil erosion, a climatological and altitudinal gradient from south to north was selected in Crete (Greece) and four locations were selected along the gradient. At the locations precipitation ranged from 1400 mm/year at the highest location to 400 mm/year at the lowest. All locations are affected by the actual land use: intensive grazing, small controlled fires, and abandoned agricultural terraces. Representative soil profiles were described in the field and analyzed in the laboratory, and rainfall simulation experiments in the field measured soil erosion over different soil surfaces and land uses. Data on physical and chemical properties were o…
Application of Magnetic Susceptibility Measurements for Identification of Technogenic Horizons in Soil Profiles on the Example of the Vistula River C…
2017
Studies on magnetic properties of soils have been recently applied in the soil environment quality monitoring in relation to basic physical and chemical properties. However, the issue of distribution of ferrimagnetic materials in particular genetic soil horizons, especially in altered soils, has not yet been considered in environmental studies. The main subject of the research was to evaluate a potential of magnetic susceptibility measurements as implements for supporting the soil classification through indication of particular distinctive genetic horizons in the soil profile. The study objects were soils whose formation was strictly conditioned by hydrotechnical regulations in the area of …
Anthropogenic processes in the evolution of a soil chronosequence on marly-limestone substrata in an Italian Mediterranean environment
2007
Due to anthropic pressure, many areas of the world are affected by a process of soil “entisolization” that leads to the formation of “anthropogenic soils”. In order to investigate Man's role in soil evolution, a survey was carried out in Southeastern Sicily (Italy), where, for years, there have been wide farming areas with anthropogenic soils. A chronosequence of anthropogenic soils in a vineyard area, cultivated for 22 years, was investigated. The first stage of the chronosequence was made by the original soils which, in the study area, had been undisturbed till the 1980's. These soils, classified as Entic Haploxerolls under the American Soil Taxonomy (ST) or Calcaric Kastanozem according …
The influence of geomorphological position and vegetation cover on the erosional and hydrological processes on a Mediterranean hillslope
1998
Soil erosion and runoff rates are assumed to be highly dependent on slope position. However, little knowledge exists about the hydrogeomorphological processes at the pedon scale that support this idea. In order to assess the hydrological and erosional behaviour of soils at different slope positions, simulated rainfall experiments (55 mm was applied during one hour) were carried out on a south-facing slope with underlying limestone in south-east Spain. In the mean terms, the erosion rates (9 g m2 hr−1) and the runoff coefficients (12%) were very low at the scale of measurement (0·25 m2). The slope position does not affect erosion rates when the measurements are carried out under extreme dry …