scholarly journals Unusual Components Within a Fine-Grained Contourite Deposit: Significance for Interpretation of Provenance and the Contourite Budget

Minerals ◽  
2020 ◽  
Vol 10 (6) ◽  
pp. 488
Author(s):  
Shereef Bankole ◽  
Jim Buckman ◽  
Dorrik Stow
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Continental Margin ◽  
Deep Water ◽  
Detailed Examination ◽  
Shallow Waters ◽  
Sediment Composition ◽  
Fine Grained ◽  
Shell Fragments ◽  
Scanning Electron

Deep-water contourite muds are an important component of many continental margin systems and are currently the focus of much interest amongst deep-water researchers. One outstanding gap in our knowledge of these systems is to understand and quantify a contourite budget, both at the small (facies) scale and at the larger drift scale. A second problem concerns the establishing of robust criteria for discriminating between contourites and associated deepwater facies—turbidites and hemipelagites. This paper contributes to these topics by detailed examination of sediment composition, with a particular focus on potentially diagnostic components, within contourites and hemipelagites from the same depositional basin. Samples were selected from Pliocene to Quaternary muddy contourites from the Gulf of Cadiz (IODP 339) and examined by scanning electron microscopy. The presence of tunicate spicules, micro-bored shell fragments, and a particular species of coccolithophore, Braarudosphaera biglowii, all indicate derivation from shallow waters and hence lateral off-shelf supply. In contrast, micro-mudclasts and fragmented bioclasts are indicative of alongslope transport in bottom currents. A normal planktic component of the contourite muds shows a significant vertical input from pelagic settling. Such diagnostic components can also help in the discrimination between contourites, turbidites and hemipelagites.

Electrochemical Deposition of Bismuth Micro- and Nanowires Using Electroplate and Lift Lithography

2012 ◽  
Vol 1477 ◽  
Author(s):  
Timea Hohl ◽  
Lori A. Lepak ◽  
Andrew Zimmerman ◽  
Samuel Hempel ◽  
Anirudha V. Sumant ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Electrochemical Deposition ◽  
Energy Dispersive Spectroscopy ◽  
Saturated Calomel Electrode ◽  
Bismuth Nitrate ◽  
Fine Grained ◽  
Ultrananocrystalline Diamond ◽  
Electrochemically Deposited ◽  
Scanning Electron

ABSTRACTPatterned micro- and nanowires of several compositions in the solution series of BixTey were electrochemically deposited using Electroplate and Lift (E&L) Lithography on Ultrananocrystalline Diamond (UNCD) templates. The composition of the deposited BixTey wires was controlled by mixing saturated solutions of bismuth nitrate and tellurium in various ratios in the electroplating bath. All wires were electroplated via pulsed depositions at -1.4V vs. the saturated calomel electrode (SCE). The morphology and composition of all wires were studied by scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS). In general, the BixTey wires were fine-grained and brittle, often fracturing during the liftoff process. By contrast, wires containing less than 5% Te are smooth, and strong enough to support their own weight without a supporting medium for a length of over 100 times the wire diameter.

Composition and Microstructures of Imperial Brass Chinese Coins

2010 ◽  
Vol 636-637 ◽  
pp. 531-537 ◽  
Author(s):  
M.J. Furtado ◽  
Rui Jorge C. Silva ◽  
M.F. Araújo ◽  
Francisco Manuel Braz Fernandes
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Equilibrium Phase ◽  
Energy Dispersive ◽  
X Ray Diffraction ◽  
X Ray ◽  
Fine Grained ◽  
Minor Elements ◽  
Brass Alloys ◽  
Scanning Electron

Twenty brass Chinese cash coins with complex compositions were studied for a better understanding of the metallurgical cash production in China, during the 17th, 18th and 19th centuries. Elemental composition was obtained through energy-dispersive micro X-ray fluorescence spectrometry of small cleaned areas on the coins rims. Results showed that these brass alloys (Cu-Zn) frequently contain up to 3% Sn, have highly variable Pb content (from n.d. up to 14%) and Fe, Sb, and As as minor elements. Microstructures were assessed by optical microscopy, scanning electron microscopy with energy dispersive spectroscopy, and preliminary micro X-ray diffraction analysis. All the coins present typical as-cast microstructures although very fine-grained, which are supported by binary (Cu-Zn) and ternary (Cu-Zn-Sn) equilibrium phase diagrams, that explain microstructural differences due to the presence of Sn in these brasses.

scholarly journals Microstructural characterisation of the Ypresian clays (Kallo-1) at nanometre resolution, using broad-ion beam milling and scanning electron microscopy

2016 ◽  
Vol 95 (3) ◽  
pp. 293-313 ◽  
Author(s):  
S. Hemes ◽  
G. Desbois ◽  
J. Klaver ◽  
J.L. Urai
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Power Law ◽  
Ion Beam ◽  
Coarse Grained ◽  
Boom Clay ◽  
Fine Grained ◽  
Pore Size Distributions ◽  
Clay Matrix ◽  
Scanning Electron

AbstractBesides the Oligocene Boom Clay, the Ypresian clays – part of the Eocene Ieper Group (Kortrijk Formation and Kortemark Member) – are currently being investigated as an alternative host rock for the deep geological disposal of radioactive waste in Belgium and the Netherlands. In this study, broad-ion-beam milling and high resolution scanning electron microscopy (BIB-SEM) analyses were carried out to analyse the mineral fabrics and microstructures of representative Ypresian clay samples from different depths of the ON-Kallo-1 borehole (Kallo, Belgium). Qualitative microstructural observations indicate that mineral fabrics and pore morphologies in fine-grained samples are comparable to those found for fine-grained Boom Clay, but most of the Ypresian clay samples analysed also contained a significant silt fraction, which is associated with larger inter-aggregate pores, coated by a thin, very low porous clay layer. Quantitative pore-shape analysis shows lower axial ratios and elongations, as well as higher roundness and circularities for pores in the clay matrix of the more coarse-grained samples, compared to the fine-grained samples. The contribution of large pores (>1 × 107nm² pore area) to the total BIB-SEM observed porosity was found to correlate with the non-clay mineral (NCM) content of a sample. Frequencies of pore sizes within the clay matrix follow a power-law distribution, hinting towards the possibility of up-scaling of the nanometre-scale observations to larger scale (micro-) structural features of the material. Power-law exponents are comparable to values found for power-law pore-size distributions within the clay matrix of the Boom Clay, which indicates similarity of the pore-space morphologies within the clay matrix of the Boom Clay and the Ypresian clays. Wood's metal injection, followed by (cooled BIB)-SEM analysis shows that all visible pores are connected via pore throats of diameter down to ~10 nm.

Type analysis of Cymbella schubartii and two new Encyonopsis species (Bacillariophyceae) from southeastern Brazil

Phytotaxa ◽  
2015 ◽  
Vol 221 (3) ◽  
pp. 247 ◽  
Author(s):  
Simone Wengrat ◽  
Gisele Carolina Marquardt ◽  
Denise De Campos Bicudo ◽  
Carlos Eduardo de Mattos Bicudo ◽  
Carlos Eduardo Wetzel ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Morphometric Analysis ◽  
Detailed Examination ◽  
Water Bodies ◽  
Southeastern Brazil ◽  
Type Analysis ◽  
Ecological Preferences ◽  
Rivers And Reservoirs ◽  
Scanning Electron

The type material of Cymbella schubartii was studied in order to clarify the differences and similarities within the complex of Encyonopsis species observed in southeastern Brazilian water bodies. Detailed examination using light and scanning electron microscopy of modern populations led us to propose two new Encyonopsis species, which are here described in details. Morphometric analysis of the valve shape supported the separation of four species: Encyonopsis schubartii, E. difficilis, E. sanctipaulensis, sp. nov. and E. linensis, sp. nov. Additionally, Cymbella perpusilla var. moreirae is formally transferred to the genus Encyonopsis. Regarding their ecological preferences, these species were found in rivers and reservoirs, especially in oligotrophic and oligo-mesotrophic environments.

Nitella singaporensis (Charophyceae, Charales): new species and implications for the taxonomy of the genus Nitella

Phytotaxa ◽  
2020 ◽  
Vol 438 (2) ◽  
pp. 80-94
Author(s):  
ROMAN E. ROMANOV ◽  
VYACHESLAV YU. NIKULIN ◽  
REGINA S.W. YEO ◽  
BOON-CHUAN HO ◽  
ANDREY A. GONTCHAROV
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
New Species ◽  
Molecular Phylogenetics ◽  
Type Specimen ◽  
Detailed Examination ◽  
Surface Pattern ◽  
Similar Species ◽  
Phylogenetic Affinities ◽  
Scanning Electron

Nitella singaporensis is described as a new species based on specimens from Singapore. This study provides detailed examination of the fully mature plant. The species is described here using multiple methods including scanning electron microscopy and molecular phylogenetics. Re-examination of the type specimen of N. caespitosa, the most similar species, will be necessary for future studies. The particular oospore surface pattern visible using scanning electron microscopy, which does not equate to previously described features, is recorded here for the first time in the genus Nitella. Nitella singaporensis is placed in section Gioallenia of subgenus Tieffallenia according to its morphological and phylogenetic affinities. The presence of adventitious cells at base of the branchlets and significance of this trait for Nitella taxonomy is discussed.

A new species of alcyonacean octocoral from the Peruvian zoogeographic region

2014 ◽  
Vol 94 (3) ◽  
pp. 493-498 ◽  
Author(s):  
Odalisca Breedy ◽  
Hector M. Guzman
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Species Richness ◽  
New Species ◽  
Light Microscopy ◽  
First Record ◽  
Shallow Waters ◽  
Morphological Studies ◽  
A New Species ◽  
Scanning Electron

The first record of the plexaurid genus Psammogorgia from the shallow waters of Peru is reported here. A new species (Psammogorgia hookeri sp. nov.) is described from Isla San Gallán, Paracas National Reserve. The new species was morphologically analysed using light microscopy and scanning electron microscopy. It is distinguished from the others in the genus by its small size; prominent calyces with wide lips around polyp apertures and without a special type of sclerites, but with a concentration of irregular, thorny spindles and wart-clubs around the calyx rim; coenenchymal sclerites that do not reach more than 0.2 mm long; the occurrence of conspicuous star-like radiates; and the colour of the colony and coenenchymal sclerites, which is coral red. The results increase species richness within a genus that has not been studied for more than a century, and contribute to the establishment of characters for further morphological studies. Additionally, the new species adds value to existing protected areas and to the octocoral biodiversity records for the Peruvian region and the eastern Pacific.

Pathogenesis of Human Hair Defects

1974 ◽  
Vol 32 ◽  
pp. 12-13
Author(s):  
P.S. Porter ◽  
T. Aoyagi ◽  
R. Matta
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Human Hair ◽  
Standard Techniques ◽  
Scanning Electron

Using standard techniques of scanning electron microscopy (SEM), over 1000 human hair defects have been studied. In several of the defects, the pathogenesis of the abnormality has been clarified using these techniques. It is the purpose of this paper to present several distinct morphologic abnormalities of hair and to discuss their pathogenesis as elucidated through techniques of scanning electron microscopy.

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