Search results for "Susceptibility"
showing 10 items of 912 documents
Chromium(III) complexes with 2-(2′-pyridyl)imidazole: Synthesis, crystal structure and magnetic properties
2011
Abstract The preparation, crystal structure and variable temperature-magnetic investigation of three 2-(2′-pyridyl)imidazole-containing chromium(III) complexes of formula PPh4[Cr(pyim)(C2O4)2]·H2O (1), AsPh4[Cr(pyim)(C2O4)2]·H2O (2) and [Cr2(pyim)2(C2O4)2(OH2)2]·2pyim · 6H2O (3) [pyim = 2-(2′-pyridyl)imidazole, C 2 O 4 2 - = dianion of oxalic acid , PPh 4 + = tetraphenylphosphonium cation and AsPh 4 + = tetraphenylarsonium cation ] are reported herein. The isomorphous compounds are made up of discrete [Cr(pyim)(C2O4)2]− anions, XPh 4 + cations [X = P (1) and As (2)] and uncoordinated water molecules. The chromium environment in 1 and 2 is distorted octahedral with Cr–N and Cr–O bond distanc…
Synthesis, structure and magnetic properties of Mn(II) and Cu(II) complexes with the dicyano-acetic acid methyl ester anion
2001
The preparation of the sodium salt of dicyano-acetic acid methyl ester (NaCH 3 OC(O)C(CN) 2 ) (NaL) is reported. The structure of this anion is related to the structure of the dicyanamide, whose chelating capability has been used to develop 2D networks. Two new complexes of formula [M(L) 2 (H 2 O) 2 ] (M=Mn 2+ ( 1 ) and Cu 2+ ( 2 )) have been synthesized and their crystal structures determined by single-crystal X-ray diffraction. The coordination geometry of Mn atom in 1 is approximately octahedral, and the Mn atoms are μ 2 -bridged by two pairs of L − resulting in an infinite one-dimensional chain. Two types of hydrogen bonds link the chains within a 3-dimensional infinite lattice. The coo…
Hepta- and tetra-nuclear copper(II) clusters self-assembled by cyano- and azacyano-carbanions
2015
International audience; Two polynuclear copper(II) complexes with hydroxido-bridging ligands and polycyanide units, [Cu{Cu(tn)}6(μ2-OH)2(μ3-OH)4Cl2](tcm)4Cl2·2H2O (1) and [{Cu(bpy)}4(OH)4(dca)2](dca)2·bpy·2H2O (2) (tn = NH2(CH2)3NH2; tcm− = [C(CN)3]−, bpy = 2,2′-bipyridyl, dca− = [N(CN)2]−) have been prepared by one-pot reactions. The structure of 1 consists of a centrosymmetric heptanuclear ion [Cu{Cu(tn)}6(μ2-OH)2(μ3-OH)4Cl2]6+. The tcm− and the halide anions which appear as counter-ions in the formula unit, play an important role in the stabilization of the complex since the hydrogen bonding between nitrogen atoms of the tcm− anion and halide anions, and hydrogen atoms of the terminal wa…
Protonated malonate: the influence of the hydrogen bonds on the magnetic behaviour
2004
One hydrogen malonato-bridged complex of formula [Cu(Hmal)2] (1) and two polymorphous malonato-bridged complexes of formula [Cu(H2O)(H2mal)(mal)] (2 and 3), in which the three species of the malonate (H2mal, Hmal−, and mal2−) are present, were synthesised and characterized by X-ray diffraction [H2mal = malonic acid]. Their structures consist of corrugated malonate layers of [Cu(Hmal)2] (1) and [Cu(H2O)(H2mal)(mal)] (2 and 3) units bridged by carboxylate–malonate groups. The layers are linked through hydrogen bonds leading to a three-dimensional network. Variable-temperature (1.9–290 K) magnetic susceptibility measurements indicate the occurrence of weak ferromagnetic interactions between th…
Strategies investigation in using artificial neural network for landslide susceptibility mapping: application to a Sicilian catchment
2013
Susceptibility assessment of areas prone to landsliding remains one of the most useful approaches in landslide hazard analysis. The key point of such analysis is the correlation between the physical phenomenon and its triggering factors based on past observations. Many methods have been developed in the scientific literature to capture and model this correlation, usually within a geographic information system (GIS) framework. Among these, the use of neural networks, in particular the multi-layer perceptron (MLP) networks, has provided successful results. A successful application of the MLP method to a basin area requires the definition of different model strategies, such as the sample selec…
A test of transferability for landslides susceptibility models under extreme climatic events: application to the Messina 2009 disaster
2014
A model building strategy is tested to assess the susceptibility for extreme climatic events driven shallow landslides. In fact, extreme climatic inputs such as storms typically are very local phenomena in the Mediterranean areas, so that with the exception of recently stricken areas, the landslide inventories which are required to train any stochastic model are actually unavailable. A solution is here proposed, consisting in training a susceptibility model in a source catchment, which was implemented by applying the binary logistic regression technique, and exporting its predicting function (selected predictors regressed coefficients) in a target catchment to predict its landslide distribu…
Data Mining Technique (Maximum Entropy Model) for Mapping Gully Erosion Susceptibility in the Gorganrood Watershed, Iran
2019
Soil erosion is a serious problem affecting most of the countries. This study was carried out in Gorganrood Watershed (Iran), which extends for 10,197 km2 and is severely affected by gully erosion. A gully headcut inven- tory map consisting of 307 gully headcut points was provided by Google Earth images, field surveys, and national reports. Gully conditioning factors including sig- nificant geo-environmental and morphometric variables were selected as predictors. Maximum entropy (ME) model was exploited to model gully susceptibility, whereas the area under the ROC curve (AUC) and draw- ing receiver operating characteristic (ROC) curves were employed to evaluate the performance of the model.…
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 …
Sediment origin and pedogenesis in the former mill pond basin of Turznice (north-central Poland) based on magnetic susceptibility measurements
2016
Abstract This paper aims to assess the usefulness of magnetic susceptibility measurements in pedological studies of mill pond sediments. The study area includes the former Turznice mill pond basin located in the south-eastern part of the Grudziądz Basin. Four soil profiles were selected within the transect located along the longitudinal axis of the basin. The following soil properties were determined in the collected samples: bulk density, particle size distribution, pH, content of carbonates, approximate content of organic matter (LOI), total organic carbon (TOC), total nitrogen (Nt), and the pseudo-total contents of metals (Fe, Mn, Cu, Zn, Pb, Ni, Cd). The obtained results were correlated…
Water erosion susceptibility mapping by applying Stochastic Gradient Treeboost to the Imera Meridionale River Basin (Sicily, Italy)
2016
Abstract Soil erosion by water constitutes a serious problem affecting various countries. In the last few years, a number of studies have adopted statistical approaches for erosion susceptibility zonation. In this study, the Stochastic Gradient Treeboost (SGT) was tested as a multivariate statistical tool for exploring, analyzing and predicting the spatial occurrence of rill–interrill erosion and gully erosion. This technique implements the stochastic gradient boosting algorithm with a tree-based method. The study area is a 9.5 km 2 river catchment located in central-northern Sicily (Italy), where water erosion processes are prevalent, and affect the agricultural productivity of local commu…