The Reduction Welding Technique Used in Pre-Columbian Times: Evidences from a Silver Ring from Incallajta, Bolivia, Studied by Microscopy, SEM-EDX and PIXE

2007 ◽  
Vol 1047 ◽  
Author(s):  
Luis Torres Montes ◽  
Jose Luis Ruvalcaba ◽  
Demetrio Mendoza Anaya ◽  
Maria de los Angeles Muñoz Collazo ◽  
Francisca Franco Velázquez ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Copper Content ◽  
Thin Sheet ◽  
External Beam ◽  
X Rays ◽  
Copper Corrosion ◽  
Archaeological Excavation ◽  
Binocular Microscope ◽  
Scanning Electron ◽  
Welding Technique

AbstractA pre-Columbian silver ring from Incallajta, Bolivia, recovered from an archaeological excavation is composed of a thin sheet of silver bent to form the ring. Two small wires in the shape of the infinity sign are joined to the surface of the ring. Four green stone beads were laid inside the four cavities formed by the wires. Energy dispersive spectroscopy (EDX) and Particle Induced X-rays Emission (PIXE) analyses of the beads proved that they were turquoise. Examination with a stereoscopic binocular microscope indicated that the two wires could have been soldered to the ring by reduction welding, because copper corrosion products were found in the interface of the welding, similar to those seen on two modern silver objects from Indonesia, decorated with granulation. Since reduction welding is a technique not reported before in pre-Columbian metallurgy, further analyses were carried out to prove that it was used here. Thus, the ring was analyzed with Scanning Electron Microscopy (SEM-EDX) and external beam PIXE, showing with certainty that the copper content in the area of the welding was higher than in any other part of the ring, with increasing copper amounts towards the center of the weld.

Defects of Platelet Function Recognized by X-Ray Imaging and Scanning Electron Microscopy

1985 ◽  
Vol 43 ◽  
pp. 610-613
Author(s):  
M.G. Baldini ◽  
S. Morinaga ◽  
D. Minasian ◽  
R. Feder ◽  
D. Sayre ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Cell Biology ◽  
Imaging Technique ◽  
Human Platelets ◽  
X Rays ◽  
X Ray ◽  
X Ray Imaging ◽  
Complex Phenomena ◽  
Scanning Electron

Contact X-ray imaging is presently developing as an important imaging technique in cell biology. Our recent studies on human platelets have demonstrated that the cytoskeleton of these cells contains photondense structures which can preferentially be imaged by soft X-ray imaging. Our present research has dealt with platelet activation, i.e., the complex phenomena which precede platelet appregation and are associated with profound changes in platelet cytoskeleton. Human platelets suspended in plasma were used. Whole cell mounts were fixed and dehydrated, then exposed to a stationary source of soft X-rays as previously described. Developed replicas and respective grids were studied by scanning electron microscopy (SEM).

STUDY OF Y-Ba-Cu-O SUPERCONDUCTORS PREPARED WITH THE OXALATE PRECIPITATION/EVAPORATION METHOD

1990 ◽  
Vol 04 (19) ◽  
pp. 1237-1244 ◽  
Author(s):  
TH. LEVENTOURI ◽  
E. LIAROKAPIS ◽  
L. MARTINEZ ◽  
F.D. MEDINA ◽  
M. MORENO ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Raman Spectroscopy ◽  
Magnetic Measurements ◽  
Preparation Procedure ◽  
X Rays ◽  
Evaporation Method ◽  
Preparation Conditions ◽  
Oxalate Precipitation ◽  
Scanning Electron

A study is presented on a series of Y-Ba-Cu-O superconductors prepared with the Oxalate Precipitation/Evaporation method. The effect of the preparation conditions on the properties of these superconductors has been studied with X-rays, scanning electron microscopy, Raman spectroscopy, and magnetic measurements. The experiments show that good quality superconductors can be fabricated with this preparation procedure and also indicate that the properties of these materials are very sensitive to the preparation conditions.

Synthesis and characterization of sodalite as matrix for conditioning chloride spent salts from pyroprocesses

2009 ◽  
Vol 1193 ◽  
Author(s):  
G. De Angelis ◽  
I. Bardez-Giboire ◽  
M. Mariani ◽  
M. Capone ◽  
M. Chartier ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Sodium Aluminate ◽  
Argon Atmosphere ◽  
Synthesis And Characterization ◽  
Chloride Salt ◽  
X Rays ◽  
Density Measurements ◽  
Quality Product ◽  
Scanning Electron

AbstractTwo different methods have been used to synthesize sodalite for conditioning of chloride salt wastes coming from pyroprocesses: the first one, starting from kaolinite through the intermediate nepheline phase; the second one, starting from silica and sodium aluminate reagents, directly. The obtained products have been characterized by means of several analyses. In particular, different instrumental techniques – stereomicroscopy, scanning electron microscopy (SEMEDS), density measurements, thermogravimetric analysis, X-rays diffraction, FTIR spectroscopy – were performed revealing that the synthesis from kaolinite is the best method, provided that rigorous conditions are followed. The use of an argon atmosphere for the preparation of pellets of reagents is strictly necessary for the obtainment of a good quality product.

scholarly journals A South American embalmed head

1970 ◽  
Vol 80 (1) ◽  
Author(s):  
Rudi Lallo ◽  
Roberto Testi ◽  
Massimo Massimelli ◽  
Raffaella Bianucci ◽  
Rosa Boano ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
3D Reconstruction ◽  
Ct Scanning ◽  
Facial Trauma ◽  
South American ◽  
X Rays ◽  
Age At Death ◽  
The University ◽  
Scanning Electron

The embalmed head of a young South American man is housed in the Museum of Anthropology and Ethnography of the University of Turin. This man, who suffered a violent facial trauma, was intentionally beheaded after his death, and his head was embalmed.   The aim of this study was to determine the age at death, the cause of death and the embalming techniques by means of CT scanning, 3D reconstruction, X-rays, histology, endoscopy and scanning electron microscopy followed by microanalysis.

BIOEROSION ON SPINICAUDATA SHELLS FROM A TRIASSIC FRESHWATER PALEOLAKE, MENDOZA, ARGENTINA

Palaios ◽  
2019 ◽  
Vol 34 (12) ◽  
pp. 616-630 ◽  
Author(s):  
EVELYN LUZ BUSTOS ESCALONA ◽  
ADRIANA CECILIA MANCUSO ◽  
CECILIA ANDREA BENAVENTE
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Brackish Water ◽  
Sedimentary Rocks ◽  
Aquatic Systems ◽  
Post Mortem ◽  
Preservation Potential ◽  
Binocular Microscope ◽  
Scanning Electron

ABSTRACT Bioerosion by microorganisms is termed microbioerosion. In aquatic systems, microbioerosion affects various substrates, most commonly relatively soluble ones such as sulfates, phosphates, and carbonates. However, the record of microbioerosion in fossil calcareous organisms in lake environments is limited. In northern Mendoza Province, at the locality Paramillos de Uspallata, Triassic sedimentary rocks outcrop, including the Agua de la Zorra Formation, which was deposited in a deltaic and lacustrine system. This study assesses possible bioerosion by microorganisms on spinicaudata shells from the lacustrine sequence and discusses their preservation potential in lacustrine environments. Spinicaudatans from the Agua de la Zorra Formation were analyzed under a binocular microscope and via scanning electron microscopy. Traces, the product of microbioerosion, preserved as molds, were assigned as Type 1 and 2 and were then compared with those generated by cyanobacteria, bacteria, chlorophyte, and fungi that inhabit fresh and brackish water environments. Microbioerosion occurs post-mortem and enhances dissolution of the spinicaudata shells. This, together with bias in extraction methodologies and sampling, is considered the reason for the rarity of spinicaudatans with traces of bioerosion in the lacustrine record.

Characterization of Synthesized SnO2 Nanoparticles and its Application for the Photo Catalytic Degradation of Eosin Y in Aqueous Solution

2021 ◽  
Vol 43 (1) ◽  
pp. 14-14
Author(s):  
Fazal Akbar Jan Fazal Akbar Jan ◽  
Muhammad Aamir Muhammad Aamir ◽  
Naimat Ullah and Husaain Gulab Naimat Ullah and Husaain Gulab
Keyword(s):  
Electron Microscopy ◽  
Aqueous Solution ◽  
Scanning Electron Microscopy ◽  
Sno2 Nanoparticles ◽  
Catalytic Degradation ◽  
Eosin Y ◽  
X Rays ◽  
Visible Spectroscopy ◽  
Uv Visible ◽  
Scanning Electron

The synthesized oxide (SnO2) nanoparticles by sol-gel method were characterized using UV-Visible spectroscopy (UV-Vis), Fourier Transform Infrared spectroscopy (FTIR), X-rays diffraction(XRD) and Scanning electron microscopy(SEM). Using X-rays diffraction analysis different parameter were calculated such as crystallite size, d-spacing, dislocation density, number of unit cell, cell volume, morphological index, micro strain and instrumental broadening. The average particle size was 28.396 nm. Scanning electron microscopy revealed that SnO2 nanopartcles are uniformly distributed. Optical properties such as band gap (energy gap = 3.6 eV) was calculated from UV-Visible spectroscopy. The characterized particles were used as photocatalyst for the degradation of Eosin dye in aqueous solution under UV light. The effect of different parameters i.e irradiation time, initial dye concentration, pH of the medium and catalyst weight on percent degradation was also studied. Mmaximum dye degradation was found at 220 minutes time interval that was 92 % using 10 ppm solution. At pH 5 the degradation of dye was found to be 94%. The catalyst dose of 0.06 g was found to be the optimum weight for the best photo catalytic degradation of Eosin Y.

ELEMENTAL ACCUMULATION PATTERNS OF THE LICHEN SPECIES PHYSCIA TRIBACOIDES NYL., HETERODERMIA DISSECTA AND BACIDIA BECKHAUSII KÖRBER FROM THE WALAYAR RF REGION, TAMIL NADU, INDIA

2011 ◽  
Vol 21 (03n04) ◽  
pp. 133-144 ◽  
Author(s):  
BHARATH PRITHIVIRAJ ◽  
E. MANIKANDAN ◽  
G. N. HARIHARAN ◽  
K. G. M. NAIR
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Tamil Nadu ◽  
Lichen Species ◽  
Supporting Evidence ◽  
X Rays ◽  
Tandem Accelerator ◽  
X Ray ◽  
Proton Beam Energy ◽  
Scanning Electron

Lichens have been used extensively as biomonitors of air quality (Richardson 1992; Seaward 1995, 2005). Lichen thalli lack a protective layer and hence accumulate airborne pollutants and particulate matter from the environment by wet and dry deposition (Nash 1996). The elements accumulated on lichen thalli can be quantitatively analysed using techniques such as Proton Induced X-ray Emission (PIXE) and Electron probe microanalysis. These techniques yield two-dimensional, quantitative element information with micron-level spatial resolution. This study used Scanning Electron Microscopy-Energy Dispersive X-ray (SEM-EDX) and PIXE to quantify elements accumulated on lichen thalli of selected species collected from polluted and unpolluted areas of the Madukkarai – Walayar forests. Thalli of selected lichen species from the study site (polluted and unpolluted) were irradiated using 1.7 MV tandem accelerator with Proton beam energy of 2 MeV. The ion induced X-rays were detected by Si ( Li ) semiconductor detector. The morphological analysis and localization of elements accumulated on these lichen samples were also carried out with the use of a SEM-EDX microanalysis using environmental scanning electron microscopy (ESEM) as supporting evidence. PIXE spectral elemental output revealed the presence of elements such as As , Ba , Br , Ca , Cu , Fe , K , Mn , Zn , Cl , Ti , Cr and Pd with the incidence of increased Calcium levels. IAEA 336 lichen reference material was used for standardization.

Mechanical and Corrosion Behaviour of Some Devices for Ostheosinthesis

2007 ◽  
Vol 23 ◽  
pp. 257-260 ◽  
Author(s):  
Brandusa Ghiban
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Femoral Fracture ◽  
Soft Tissues ◽  
Corrosion Behaviour ◽  
Structural Features ◽  
X Rays ◽  
Hard Tissues ◽  
Mechanical Devices ◽  
Scanning Electron

Orthopaedic implants represent mechanical devices which may be used for different purposes in human skeleton. such as either repairing of soft tissues (ligaments) or hard tissues (fractures. osteotomy. partial or total replacements). The aim of present paper is to put in evidence some macro and micro structural features revealed at state of surface after 5 months of implant in a female femoral fracture. Investigated surfaces were analyzed by optical and scanning electron microscopy and by X-Rays diffraction.

Surface Analysis of the Tarnishing Layer in Silver Alloys

MRS Advances ◽  
2017 ◽  
Vol 2 (63) ◽  
pp. 3983-3989 ◽  
Author(s):  
Janette Ortíz-Corona ◽  
José L. Ruvalcaba-Sil ◽  
Edgar Casanova-González ◽  
Francisco J. Rodríguez-Gómez
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Copper Content ◽  
Black Film ◽  
Silver Alloys ◽  
X Ray ◽  
Ammonium Sulfide ◽  
Sulfide Solution ◽  
Scanning Electron

AbstractAncient silver artifacts, when exposed to environments that contain sulfides (H2S), become tarnished and a black film is formed on the surface. The current study deals with the role of copper content and oxygen in the formation of tarnishing in the silver alloys 0.925, 0.800 and 0.720. An ammonium sulfide solution was used as an accelerator of the tarnishing process for different immersion conditions. The analysis of the tarnishing layer in silver alloys was performed by Raman Spectroscopy, Scanning Electron Microscopy - Energy Dispersive X-ray spectroscopy (SEM-EDS) and X-Ray Fluorescence (XRF). The formation of the tarnishing layer was found to be influenced by copper and oxygen contents. The corrosion products under the conditions studied were found to be mainly acanthite and jalpaite.

Microstructural investigation of the Carancas meteorite

2010 ◽  
Vol 10 (2) ◽  
pp. 105-112 ◽  
Author(s):  
Kani Rauf ◽  
Anthony Hann ◽  
Chandra Wickramasinghe ◽  
Barry E. DiGregorio
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
High Temperature ◽  
Intermediate Zone ◽  
Hydroxyl Groups ◽  
X Rays ◽  
Microstructural Investigation ◽  
Dark Zone ◽  
Transmission Electron ◽  
Scanning Electron

AbstractParticles in the Carancas meteorite were examined by electron microscopy (transmission electron microscopy/scanning electron microscopy), energy dispersive analysis of X-rays (EDAX) and Fourier Transform Infrared spectroscopy. Scanning electron microscopical observations reveal that the particles of variable sizes have a stony appearance. Many of these particles show fractures in places, thus confirming an ealier observation that the meteorite was subjected to a high-velocity impact. The outer rim of many aggregates displays a mud crack-like texture. At high magifications, this texture shows ovoid and elongated features, which appear similar to microfossils found in other meteorites.As revealed by both scanning and transmission electron microscopy, some particles show three clearly marked zones, distinguishable by their differences in electron density and texture: a light zone, a dark zone and an intermediate zone. The EDAX analysis of these particles shows that the light zone is composed of silicates rich in Fe, Ni and S (the elements of troilite and pentlandite). The dark zone contains high concentrations of Mg and Si (the major elements of high-temperature minerals, such as forsterite, Mg2SiO4 and enstatite, MgSiO3) intermixed with carbonates and traces of Al, Ca and Na. The intermediate zone also contains high-temperature minerals and Fe-Ni rich silicates.The Carancas meteorite produces an infrared waveband showing prominent features of some carbonate species, amorphous and crystalline silicates, and olivine groups. Hydrated silicates and hydroxyl groups are less abundant, as shown by the presence of small humps between 2.5 and 8.0 μm.The abundance of high-temperature minerals and iron-rich metal confirms an earlier observation that the meteorite is an ordinary H4/5 chondrite. Some particles in the Carancas meteorite are found to have structural and chemical characteristics similar to those of the 81P/Wild 2 comet.

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