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Magnetic Investigations (magnetic + investigation)

Distribution by Scientific Domains

Earth and Environmental Science	63%
Chemistry	27%

Selected Abstracts

Magnetic Investigations on Six Compounds with the General Formula (Ca,Y)Ba(Co,Fe,Al,Zn)4O7 and the Structures of YBaCoFeZn2O7 and YBaCo2FeZnO7.

CHEMINFORM, Issue 51 2005
Martin Valldor
Abstract For Abstract see ChemInform Abstract in Full Text. [source]

Magnetic investigation of heavy metals contamination in urban topsoils around the East Lake, Wuhan, China

GEOPHYSICAL JOURNAL INTERNATIONAL, Issue 2 2007
Tao Yang
SUMMARY Magnetic measurements and heavy metal analyses were performed on 133 samples from the urban soils around the East Lake in Wuhan, China. Samples were collected from four areas with different environmental settings: a heavy industrial area well known for thermal power generation and steel works; villages located in the downwind area of the industrial area; a main road with heavy traffic and roads around the East Lake. Results show that concentrations of magnetic particle and heavy metals in urban topsoils are significantly elevated due to the input of coarser-grained magnetite from industrial (e.g. power generation and steel production) and other anthropogenic activities (e.g. vehicle emissions). Concentration-related magnetic parameters, for example, magnetic susceptibility, saturation isothermal remanent magnetization and anhysteretic remanent magnetization, significantly correlate with the concentration of heavy metals. Moreover, in terms of grain sizes, the magnetic particles of different origins can be efficiently discriminated at the studied region. Therefore, magnetic measurements provide a basis for discrimination and identification of different contamination sources, and can be used as an economic alternative to chemical analysis when mapping heavy metal contamination in urban soil around the East Lake region, Wuhan, China. [source]

Electron-Sponge Behavior, Reactivity and Electronic Structures of Cobalt-Centered Cubic Co9Te6(CO)8 Clusters

EUROPEAN JOURNAL OF INORGANIC CHEMISTRY, Issue 12 2008
Mustapha Bencharif
Abstract Extended investigations of the reaction sequence [Cp,2Nb(Te2)H]/CH3Li/[Co2(CO)8] (Cp, = tBuC5H4) led to the identification of Lin[3] {3 = [Co9Te6(CO)8]; n = 1, 2} salts through their transformation with [PPN]Cl into [PPN]n[3] (PPN = Ph3PNPPh3). These compounds form in the solid state columnar ([PPN][3]) or undulated 2D ([PPN]2[3]) supramolecular networks. Electrochemical studies of [Cp*2Nb(CO)2][3] (Cp* = C5Me5) or [Na(THF)6][3] revealed the presence of the redox couples [3],/[3]2,/[3]3,/[3]4,/[3]5, regardless of the nature of the cation, whereas in the anodic part oxidative degradation of the cluster takes place. This behavior is in agreement with the observation that [3], containing salts form with PPh3AuCl or dppe decomposition products like [(PPh3)2Au][CoCl3PPh3] or [Co(CO)2dppe]2(,-Te). A neutral cluster comprising the Co@Co8(,4 -Te)6 core formed in the reaction of [Cp*2Nb(CO)2][Co11Te7(CO)10] with PPh3AuCl, which gave [Co9Te6(CO)4(PPh3)4] (4) after oxidative cluster degradation and CO substitution. 4 was characterized by X-ray crystallography. DFT calculations carried out on all members of the [3]n (n = +1 to ,5) family and on related species indicate that there is no significant Jahn,Teller distortion (and therefore no connectivity change) for any of the considered electron counts. Magnetic investigations on [PPN][3] show that the ground state of [3], is a spin triplet with spins interacting antiferromagnetically in a 1D space.(© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008) [source]

A meteorite impact crater field in eastern Bavaria?

METEORITICS & PLANETARY SCIENCE, Issue 2 2005
A preliminary report
The depressions are bowl-shaped, have high circularity and a characteristic rim. Most of them were formed in unconsolidated glacial gravels and pebbles intermixed with fine-grained sand and clay. Magnetic investigations reveal weak anomalies with amplitudes of less than ±10 nano Tesla (nT). In some cases, the origins of the anomalies are suspected to be due to human activity within the structures. So far, no traces of meteoritic material have been detected. An evident archaeological or local geological explanation for the origin of the craters does not exist. A World War I and II explosive origin can be excluded since trees with ages exceeding 100 years can be found in some craters. One crater was described in 1909. Carbon-14 dating of charcoal found in one crater yielded an age of 1790 ± 60 years. Hence, a formation by meteorite impacts that occurred in Celtic or early medieval times should be considered. A systematic archaeological excavation of some structures and an intensified search for traces of meteoritic material are planned. [source]

Discovery of the causeway and the mortuary temple of the Pyramid of Amenemhat II using near-surface magnetic investigation, Dahshour, Giza, Egypt

GEOPHYSICAL PROSPECTING, Issue 2 2010
T. Abdallatif
ABSTRACT The main outbuildings of the Amenemhat II pyramid complex in Dahsour were yet to be discovered due to a very long subjection of the area to the military authorities and also the demolition of the pyramid itself. We describe the discovery of some of these outbuildings using near-surface magnetic investigations. A gradiometer survey was conducted in the area east of the pyramid to measure the vertical magnetic gradient with a high resolution instrument at 0.5 m sampling interval. The data showed some undesirable field effects such as grid discontinuities, grid slope, traverse stripe effects, spikes and high frequencies originating from recent ferrous contamination. These undesirable effects were addressed to produce an enhanced display. We have successfully detected four main structures in the area east of the pyramid; the causeway that connected the mortuary temple with the valley temple during the Middle Kingdom of the 12th Dynasty, the mortuary temple and its associated rooms, ruins of an ancient working area and an Egyptian-style tomb structure called a Mastaba. An improved recognition for these structures was accomplished by using the analytic signal and Euler deconvolution techniques. Excavation of a small part within the study area has proven the reliability of magnetic discoveries and the shallowness and composition of the detected features. [source]

Integrated technologies for archaeological investigation; the Celone Valley project

ARCHAEOLOGICAL PROSPECTION, Issue 3 2007
Marcello Ciminale
Abstract A non-intrusive investigation integrating complementary technologies was carried out at four vast archaeological settlements located in the northern part of Apulia (Southern Italy). An aerial photographic survey combined with a high-resolution magnetic investigation was used to detect many buried archaeological features. After processing, both crop marks and magnetic anomalies appeared very sharp and well-defined, outlining the shape and plan of the buried structures with notable accuracy. Furthermore, differential global positioning system measurements were carried out in order to geocode the magnetic grids, to orthorectify the oblique coloured photographs and to make these data sets suitable for input into a GIS; a very good spatial correlation and a more rigorous and comprehensive interpretation of the various data elements were attained. Finally, as a result of this combined and accurate multilayer analysis, an archaeological interpretation was proposed, enabling useful information to be obtained on the transformations that have occurred over time at these study sites. Copyright © 2007 John Wiley & Sons, Ltd. [source]

Tectonic and environmental evolution of Quaternary intramontane basins in Southern Apennines (Italy): insights from palaeomagnetic and rock magnetic investigations

GEOPHYSICAL JOURNAL INTERNATIONAL, Issue 2 2010
M. Porreca
SUMMARY Southern Apennines is characterized by active extensional tectonics with NE,SW stretching direction. The seismicity of the region is very well understood and continuously monitored. In contrast, the onset of extensional tectonics is chronologically poorly constrained. The aim of this study is that to give important constraints on the development of extensional regime and the onset of the continental deposition during Quaternary in Southern Apennines. We report the results of palaeomagnetic and rock magnetic analyses from four Quaternary small intramontane basins in the Picentini Mountains (Southern Apennines). The sedimentary sequences are located at different altitudes, from 600 to 1200 m a.s.l., and were deposited in fluvial-lacustrine environments. We sampled 29 sites in clays and lacustrine limestones from Tizzano, Piano del Gaudo and Acerno basins and in red palaeosoils and matrix-supported conglomerates from the Iumaiano basins. In the clay and limestones samples magnetite, titano-magnetite, hematite and iron-sulphide have been recognized as the main magnetic carriers, whereas magnetite and hematite characterize the Iumaiano conglomerates and red soils. Palaeomagnetic results have been integrated with published radiometric data in order to constrain the age of each sedimentary basins. Sites from the Iumaiano basin, which represents the substrate of the Tizzano and Piano del Gaudo basins, show a reverse polarity and therefore have been attributed to the lower Matuyama chron. In contrast, palaeomagnetic data from Tizzano basin show a transition from reversed to normal polarity along the exposed section, which has been interpreted as the Matuyama/Brunhes transition. Sites from Acerno and Piano del Gaudo basins show a normal polarity, which, according to radiometric and pollen data, have been correlated to the Brunhes epoch. On the base of such results we discuss the tectono-stratigraphic evolution of the basins and the role of extensional tectonics in this portion of the Southern Apennine during the Quaternary. [source]

Discovery of the causeway and the mortuary temple of the Pyramid of Amenemhat II using near-surface magnetic investigation, Dahshour, Giza, Egypt

GPR, ERT and magnetic investigations inside the Martyrium of St Philip, Hierapolis, Turkey

ARCHAEOLOGICAL PROSPECTION, Issue 3 2009
Luigia Nuzzo
Abstract Hierapolis, Denizli, Turkey, was one of the most important Hellenistic-Roman cities in Asia Minor. Located about 250,km east of Izmir, the area is a UNESCO World Heritage Site because of its magnificent archaeological remains and the white travertine pool formations created by its peculiar geothermal setting. The Italian Archaeological Mission in more than 50 years of activity in Hierapolis has brought to light and restored important vestiges of the ancient city, helping to understand the urban layout in the various epochs of its development. In 2001,2003 geophysical surveys were performed by the University of Lecce in several areas inside the archaeological site of Hierapolis to support the archaeological excavations. This paper reports the results of the integrated geophysical surveys performed in 2003 inside the Martyrium of Saint Philip, a mausoleum built on the place where it is believed that the Apostle was martyred. Ground-penetrating radar (GPR), electrical resistivity tomography (ERT) and magnetic gradient investigations were carried out in the central octagonal room, whereas the accessible lateral rooms were surveyed with GPR and occasionally ERT. The acquisition was performed along a series of closely spaced lines and the processed data were visualized as two-dimensional vertical sections (GPR), map view (magnetic gradiometry), depth slices or three-dimensional volumes (GPR and ERT) to allow an integrated interpretation of the geophysical results. The analysis of the geophysical datasets revealed a series of anomalies in both the central and lateral rooms that could be ascribed to the building foundations and to other possible archaeological structures, probably related to earlier stages of the sacred building and to tombs, as well as other anomalies (voids, fractures) of presumable natural origin. Copyright © 2009 John Wiley & Sons, Ltd. [source]

Prompt magnetic investigations of archaeological remains in areas of infrastructure development: Israeli experience

ARCHAEOLOGICAL PROSPECTION, Issue 3 2001
Lev V. Eppelbaum
Abstract Magnetic prospecting is the most widely used method for the investigation of archaeological remains in the world. This method is often applied before and during various engineering exploration (e.g. road construction, preparing areas for various types of building) and areas of agricultural utilization. Taking into account an extremely high concentration of archaeological sites of different age at Israeli territory, prompt geophysical,archaeological assessment of areas allocated for engineering and agricultural utilization, is a necessary preliminary component of the design process. However, noise both of natural and artificial origin strongly complicates interpretation of observed magnetic anomalies. The most significant disturbing factors are oblique magnetization (magnetization vector in the Israeli territory is inclined about 45°), complex geological structure (presence of a variety of disturbing bodies) of investigated site, influence of rugged topography, as well as influence of modern iron-containing objects. The non-conventional procedures developed by the authors are intended for application in such complicated environments and include elimination of noise from various sources, selection of ,useful' anomalies against the noise background, qualitative and quantitative interpretation of anomalies and three-dimensional physical,geological modelling. Effective integration of these procedures with other interpretation methods allowed rapid localization of tens of archaeological remains and their protection from unpremeditated destruction. Copyright © 2001 John Wiley & Sons, Ltd. [source]

Compressed Octahedral Coordination in Chain Compounds Containing Divalent Copper: Structure and Magnetic Properties of CuFAsF6 and CsCuAlF6

CHEMISTRY - A EUROPEAN JOURNAL, Issue 20 2004
Zoran Mazej Dr.
Abstract Crystal structures and magnetic investigations of CuFAsF6 and CsCuAlF6 are reported. Together with KCuAlF6, these appear to be the only examples of Jahn,Teller pure CuII compounds containing only one type of ligand that exhibits a compressed octahedral coordination geometry. The Rietveld method has been used for refining the CsCuAlF6 structure based on neutron powder diffraction data at 4 K. The compound crystallizes in space group Pnma (no. 62) with a=7.055(1), b=7.112(1), c=10.153(1) Å and Z=4 at 4 K. The structure is built from infinite [CuF5]n3n, chains of [CuF6]4, octahedra running along the [1,0,0] direction and (AlF6)3, octahedra connected by corners in the trans position, thus giving rise to chains oriented along the [0,1,0] direction. Single crystals of CuFAsF6 were prepared under solvothermal conditions in AsF5 above its critical temperature. The structure was determined from single-crystal data. CuFAsF6 crystallises in the orthorhombic space group Imma (No. 74) with a=10.732(5), b=6.941(3), c=6.814(3) Å and Z=4 at 200 K. The structure can also be described in terms of one-dimensional infinite [CuF5]n3n, chains of tilted [CuF6]4, octahedra linked by trans -vertices running along the b axis. The [CuF5]n3n, chains are connected through [AsF6], units sharing joint vertices. The compressed octahedral coordination of CuII atoms in CuFAsF6 and CsCuAlF6 compounds at room temperature is confirmed by Cu K-edge EXAFS (extended x-ray absorption fine structure) analysis. For both compounds strong antiferromagnetic interactions within the [CuF5]n3n, chains were observed (,p=,290±10 K and ,p=,390±10 K for CuFAsF6 and CsCuAlF6, respectively). The peculiar magnetic behaviour of chain compounds containing divalent copper at low temperature could be related to uncompensated magnetic moments in the one-dimensional network. [source]