The investigation of the permeable ceramics' porous structure by means X-Ray micro-tomography

Reconstructive tomography is a new technique in diagnostic radiology for imaging cross-sectional planes of the human body /1/. A collimated beam of X-rays is scanned through a thin slice of the body and the transmitted intensity is recorded by a detector giving a linear shadow graph or projection (see fig. 1). Many of these projections at different angles are used to reconstruct the body-layer, usually with the aid of a computer. The picture element size of present tomographic scanners is approximately 1.1 mm2.Micro tomography can be realized using the very fine X-ray source generated by the focused electron beam of a scanning electron microscope (see fig. 2). The translation of the X-ray source is done by a line scan of the electron beam on a polished target surface /2/. Projections at different angles are produced by rotating the object.During the registration of a single scan the electron beam is deflected in one direction only, while both deflections are operating in the display tube.

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Synchrotron X-ray phase contrast micro tomography to explore the morphology of abdominal organs in Pterostichus melas italicus Dejean, 1828 (Coleoptera, Carabidae)

Arthropod Structure & Development ◽

10.1016/j.asd.2021.101044 ◽

2021 ◽

Vol 62 ◽

pp. 101044

Author(s):

Sandro Donato ◽

Maria Luigia Vommaro ◽

Giuliana Tromba ◽

Anita Giglio

Keyword(s):

Phase Contrast ◽

X Ray ◽

Abdominal Organs ◽

Micro Tomography

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Freeze–Thaw Resistance and Air-Void Analysis of Concrete with Recycled Glass–Pozzolan Using X-ray Micro-Tomography

Materials ◽

10.3390/ma14010154 ◽

2020 ◽

Vol 14 (1) ◽

pp. 154

Author(s):

Marija Krstic ◽

Julio F. Davalos ◽

Emanuele Rossi ◽

Stefan C. Figueiredo ◽

Oguzhan Copuroglu

Keyword(s):

Fly Ash ◽

Pore Structure ◽

The United States ◽

Adsorption Method ◽

X Ray ◽

Freeze Thaw ◽

Void System ◽

Spatial Parameters ◽

Micro Tomography ◽

Air Void

Recent studies have shown promising potential for using Glass Pozzolan (GP) as an alternative supplementary cementitious material (SCM) due to the scarcity of fly ash and slag in the United States. However, comprehensive studies on the freeze–thaw (FT) resistance and air void system of mixtures containing GP are lacking. Therefore, this study aimed to evaluate GP’s effect on FT resistance and characterize mixtures with different GP contents, both macro- and microscopically. In this study, six concrete mixes were considered: Three mixes with 20%, 30% and 40% GP as cement replacements and two other comparable mixes with 30% fly ash and 40% slag, as well as a mix with 100% Ordinary Portland cement (OPC) as a reference. Concrete samples were prepared, cured and tested according to the ASTM standards for accelerated FT resistance for 1000 cycles and corresponding dynamic modulus of elasticity (Ed). All the samples showed minimal deterioration and scaling and high F/T resistance with a durability factor of over 90%. The relationships among FT resistance parameters, air-pressured method measurements of fresh concretes and air void analysis parameters of hardened concretes were examined in this study. X-ray micro-tomography (micro-CT scan) was used to evaluate micro-cracks development after 1000 freeze–thaw cycles and to determine spatial parameters of air voids in the concretes. Pore structure properties obtained from mercury intrusion porosimetry (MIP) and N2 adsorption method showed refined pore structure for higher cement replacement with GP, indicating more gel formation (C-S-H) which was verified by thermogravimetric analysis (TGA).

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A new species of anapid spider (Araneae: Araneoidea, Anapidae) in Eocene Baltic amber, imaged using phase contrast X-ray computed micro-tomography

Zootaxa ◽

10.11646/zootaxa.2742.1.4 ◽

2011 ◽

Vol 2742 (1) ◽

pp. 60 ◽

Cited By ~ 17

Author(s):

DAVID PENNEY ◽

ANDREW MCNEIL ◽

DAVID I. GREEN ◽

ROBERT BRADLEY ◽

YURI M. MARUSIK ◽

...

Keyword(s):

New Species ◽

Phase Contrast ◽

Baltic Amber ◽

X Ray ◽

The Family ◽

X Ray Computed ◽

Micro Tomography ◽

The Baltic ◽

A New Species ◽

Eocene Amber

A new species of the extant spider family Anapidae is described from a fossil mature male in Eocene amber from the Baltic region and tentatively assigned to the genus Balticoroma Wunderlich, 2004. Phase contrast X-ray computed micro-tomography was used to reveal important features that were impossible to view using traditional microscopy. Balticoroma wheateri new species is easily diagnosed from all other anapids by having clypeal extensions that run parallel to the ectal surface of the chelicerae and in having the metatarsus of the first leg highly reduced and modified into what is presumably a y-shaped clasping structure. Although only a single extant anapid species occurs in northern Europe, the family was diverse in the Eocene. The discovery of yet another anapid species in Baltic amber supports the idea that Eocene European forests may have been a hotspot of evolution for this family of spiders.

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