scholarly journals Mechanical Properties of Enamel Nanocomposite

2013 ◽  
Vol 2013 ◽  
pp. 1-15 ◽  
Author(s):  
Nilormi Biswas ◽  
Arjun Dey ◽  
Saugata Kundu ◽  
Himel Chakraborty ◽  
Anoop K. Mukhopadhyay
Keyword(s):  
Electron Microscopy ◽  
Fracture Toughness ◽  
Scanning Electron Microscopy ◽  
X Ray ◽  
Young’S Moduli ◽  
Relative Differences ◽  
First Time ◽  
Microindentation Technique ◽  
Work Of Fracture ◽  
Scanning Electron

For adult Indian premolar teeth, we report for the first time ever the simultaneous evaluations of nanohardness, Young's modulus, and fracture toughness of the enamel nanocomposite. The nanohardness and Young's moduli were evaluated from near the beginning of the middle enamel region to within ~10 μm of the dentino-enamel junction (DEJ) and in the dentin region using the nanoindentation technique. The fracture toughness from near the middle of the enamel region to near the DEJ zone was measured using the microindentation technique. The deformation was studied using scanning electron microscopy (SEM) and field emission scanning electron microscopy (FESEM). The relative differences in the extents of biomineralization in the enamel and dentin regions were studied by the energy dispersive X-ray (EDS) technique. The variations of the toughness of the enamel as a function of the toughness of the protein matrix phase have been analyzed which showed that the predicted value of the toughness of the protein present in the nanocomposite was comparable to that of other bioproteins reported in the literature. Further, the work of fracture estimated from the measured value of toughness of the enamel nanocomposite agreed well with the experimental data reported in the literature.

New perspectives on Nephridiacanthus major (Acanthocephala: Oligacanthorhynchidae) collected from hedgehogs in Iran

2020 ◽  
Vol 94 ◽  
Author(s):  
O.M. Amin ◽  
M. Sharifdini ◽  
R.A. Heckmann ◽  
M. Zarean
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Phylogenetic Analysis ◽  
Chemical Analysis ◽  
Central Asia ◽  
Molecular Profile ◽  
X Ray ◽  
The Family ◽  
First Time ◽  
Scanning Electron

We describe morphological features not previously reported for this old acanthocephalan Nephridiacanthus major (Bremser, 1811 in Westrumb, 1821) Golvan, 1962 first described over 200 years ago. Our specimens were collected from long-eared hedgehog Hemiechinus auritus (Gmelin, 1770) (Erinaceidae) in Iran. We compare the morphometrics of our material with others previously reported from the same host in Iran, Russia, central Asia and Europe. Our specimens had markedly smaller proboscides, proboscis hooks and lemnisci than those reported from Russia and central Asia, but comparable measurements of other structures with specimens previously described from other collections. We document our new observations with scanning electron microscopy features not previously demonstrable by other observers and provide a chemical analysis of proboscis hooks using energy-dispersive X-ray analysis for the first time. The molecular profile of this acanthocephalan, based on 18S rDNA and cox1 genes, was generated for the first time. The phylogenetic analysis showed that N. major is placed in a clade of the family Oligacanthorhynchidae, well separated from the families Moniliformidae and Gigantorhynchidae.

scholarly journals Calcium Oxalates in Lichens on Surface of Apatite-Nepheline Ore (Kola Peninsula, Russia)

Minerals ◽  
2019 ◽  
Vol 9 (11) ◽  
pp. 656 ◽  
Author(s):  
Frank-Kamenetskaya ◽  
Ivanyuk ◽  
Zelenskaya ◽  
Izatulina ◽  
Kalashnikov ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Phase Composition ◽  
Kola Peninsula ◽  
Metabolic Activity ◽  
X Ray ◽  
Calcium Oxalates ◽  
Essential Questions ◽  
First Time ◽  
Scanning Electron

The present work contributes to the essential questions on calcium oxalate formation under the influence of lithobiont community organisms. We have discovered calcium oxalates in lichen thalli on surfaces of apatite-nepheline rocks of southeastern and southwestern titanite-apatite ore fields of the Khibiny peralkaline massif (Kola Peninsula, NW Russia) for the first time; investigated biofilm calcium oxalates with different methods (X-ray powder diffraction, scanning electron microscopy, and EDX analysis) and discussed morphogenetic patterns of its formation using results of model experiments. The influence of inorganic and organic components of the crystallization medium on the phase composition and morphology of oxalates has been analyzed. It was shown that, among the complex of factors controlling the patterns of biogenic oxalate formation, one of the main roles belongs to the metabolic activity of the lithobiont community organisms, which differs significantly from the activity of its individuals.

scholarly journals Development of Sustainable and Eco-Friendly Materials from Termite Hill Soil Stabilized with Cement for Low-Cost Housing in Chad

Buildings ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 86
Author(s):  
Assia Aboubakar Mahamat ◽  
Numfor Linda Bih ◽  
Olugbenga Ayeni ◽  
Peter Azikiwe Onwualu ◽  
Holmer Savastano ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Mechanical Properties ◽  
Fracture Toughness ◽  
Scanning Electron Microscopy ◽  
Low Cost ◽  
Sub Saharan Africa ◽  
Ex Situ ◽  
Termite Mound ◽  
X Ray ◽  
Scanning Electron

This paper explores the effects of cement stabilization (5, 10, 15 and 20 wt%) on the structural and mechanical properties (compressive/flexural strengths and fracture toughness) of abandoned termite mound soil. The crystal structures and crystallinity of the constituents were determined using X-ray diffraction (XRD), while the microstructure was characterized via scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDS). The functional groups were also identified using Fourier transform infra-red spectroscopy (FTIR). The compressive/flexural strengths of the stabilized and un-stabilized termite mound soil were also studied after curing for 7, 14 and 28 days. The fracture toughness mechanism was analyzed with the aid of the R-curve method. Additionally, the underlying deformation and cracking mechanisms are elucidated via in-situ/ex-situ optical and scanning electron microscopy. The stabilized termite mound soil displayed the highest mechanical properties of 13.91 MPa, 10.25 MPa and 3.52 kPa·m1/2 for compressive strength, flexural strength and fracture toughness, respectively. Besides displaying good mechanical properties and being locally available at no cost, renewable and an eco-friendly material, the termite mound soil will contribute to lowering the cost of housing in Sub-Saharan Africa, particularly in Chad.

Mechanical Properties of AlMgB14-xTiB2 Prepared by Field Activated and Pressure Assisted Synthesis

2013 ◽  
Vol 745-746 ◽  
pp. 652-656
Author(s):  
Yang Miao ◽  
Wen Liu ◽  
Lei Zhuang ◽  
Hui Ling Cheng ◽  
Qing Sen Meng
Keyword(s):  
Electron Microscopy ◽  
Mechanical Properties ◽  
Fracture Toughness ◽  
Scanning Electron Microscopy ◽  
Mechanical Alloying ◽  
Composite Ceramic ◽  
X Ray Diffraction ◽  
X Ray ◽  
Wear Tests ◽  
Scanning Electron

In this paper, Mechanical alloying (MA) and field activated and pressure assisted synthesis (FAPAS) were used for preparing the ultra-hard, super-abrasive AlMgB14-xTiB2 composite ceramic. The samples were fabricated at 1500 under a pressure of 60 MPa. The microstructures and compositions of samples were observed and determined by scanning electron microscopy (SEM), energy dispersive X-ray analysis (EDX), X-ray diffraction (XRD). It was indicated that addition of TiB2 was effective for increasing both quantities. A maximum Vichers hardness of 38.5GPa and a fracture toughness of 3.85MPam½ of AlMgB14 reinforced with 70 wt.% of TiB2 were achieved. Abrasion wear tests showed that adding TiB2 would improve the wearability obviously.

scholarly journals Synthesis of copper nanoshales from a Triton™ X-100/cyclohexane/water ternary microemulsion system

2016 ◽  
Vol 81 (4) ◽  
pp. 395-401 ◽  
Author(s):  
Hossein Heli ◽  
Naghmeh Sattarahmady ◽  
Fatemeh Pourbahman
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Chemical Reduction ◽  
Microemulsion System ◽  
X Ray Diffraction ◽  
X Ray ◽  
Xrd Patterns ◽  
Triton X ◽  
First Time ◽  
Scanning Electron

Shale-like copper nanostructure was synthesized for the first time from a water-in-oil microemulsion medium comprising Triton? X-100/cyclohexane/water ternary system. The nanoshales were synthesized through chemical reduction by hydrazinium hydroxide in alkaline medium. The nanoshales were characterized by scanning electron microscopy (SEM) and X-ray diffraction (XRD) patterns.

Microstructure and Properties of Zirconia-Mullite Nanocomposites Obtained from Si-Al-Zr-O Amorphous Bulks Doped with CaO and MgO

2011 ◽  
Vol 142 ◽  
pp. 87-91 ◽  
Author(s):  
Xiao Ping Tan ◽  
Shu Quan Liang ◽  
Li Yuan Chai
Keyword(s):  
Electron Microscopy ◽  
Fracture Toughness ◽  
Scanning Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Thermal Treatment ◽  
Anisotropic Growth ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron ◽  
Scanning Electron

Zirconia-mullite nanocomoposites were prepared from Si-Al-Zr-O amorphous bulk with diffrent content of CaO and MgO by two-step thermal treatment between 900 and 1200°C. The effects of the additives on the phase and microsturcture were studied by X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM) and transmission electron microscopy (TEM). The results show that the addition of CaO promotes cristobalite phase formation and the anisotropic growth of mullite grains. An indention micro-crack method was used to measure the fracture toughness of zirconia-mullite nanocomoposites. The results demonstrate that the fracture toughness increases with higher concentration of CaO. The improvement of fracture toughness is attributed to the anisotropic growth of grains.

scholarly journals Synthesis and characterization of AlMgB14 hot pressed under different environments

2017 ◽  
Vol 49 (3) ◽  
pp. 311-317 ◽  
Author(s):  
Zhou Yumei ◽  
Zhang Fenglin ◽  
Pengcheng Li ◽  
Bai Kun ◽  
Shanghua Wu ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Fracture Toughness ◽  
Scanning Electron Microscopy ◽  
Single Phase ◽  
Synthesis And Characterization ◽  
Carbon Powder ◽  
X Ray ◽  
Spinel Mgal2o4 ◽  
Scanning Electron

AlMgB14 hot pressed under different environments from the elemental powders was investigated. The microstructure of the products was analyzed by scanning electron microscopy (SEM) with energy dispersive X-ray spectroscopy (EDX) and X-ray diffractometer (XRD). The density, hardness and fracture toughness of AlMgB14 were also examined. The results show that single phase of MgAl2O4 is formed in hot pressed Al-Mg-B system in air. The addition of carbon powder cannot reduce the formation of MgAl2O4. Additional Al (10 wt.%) and Mg (10 wt.%) can effectively compensate for their loss in the formation of MgAl2O4 and enhance the production of AlMgB14 under agron atmosphere. The AlMgB14 with 10 vol.% spinel MgAl2O4 owns a hardness of 28.42 GPa and a fracture toughness of 2.92 MPa?m1/2.

scholarly journals Stratigraphic study of Qalqula Formation, Sulaymaniyah Governorate - NE Iraq

2019 ◽  
Vol 23 (10) ◽  
pp. 60
Author(s):  
Mohammad Jamil Ali Al-Talabani
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Late Jurassic ◽  
Late Triassic ◽  
X Ray Diffraction ◽  
Thin Sections ◽  
X Ray ◽  
Mineralogical Investigation ◽  
First Time ◽  
Scanning Electron

Qulqula Formation studied in Suren mountain - Sulaymaniyah- NE Iraq. 10 samples collected from the outcrop near Kani Seif Hamid area. Petrographic and mineralogical investigation carried out, thin sections, X- ray Diffraction (XRD) and Scanning Electron Microscopy (SEM) with Energy Dispersive X-ray Analysis (EDX) samples were prepared and analysed in Wollongong University-Australia.  Preliminary results show that the lower part of Qulqula Formation in the studied section undergo severe recrystallization and partly dolomitized. In addition, from chronostratigraphic viewpoint, Qulqula Formation in the studied area thought to represent Late Triassic age. This study report for the first time the occurrence of Calpionellids fossils, two species were identified; Tintinnopsella remanei Borza and Calpionellites major (Colom) which represent the Late Jurassic - Early Cetaceous age (i.e. Late Tithonian - Early Valanginian respectively). This coincided with the proposed age results from previous works.   http://dx.doi.org/10.25130/tjps.23.2018.170 

Identification of calcium oxalate crystals in dried or fixed tobacco leaf

1984 ◽  
Vol 42 ◽  
pp. 288-289
Author(s):  
Vicki L. Baliga ◽  
Mary Ellen Counts
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Calcium Oxalate ◽  
Growth And Development ◽  
Polarized Light ◽  
Calcium Oxalate Crystals ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron ◽  
Scanning Electron

Calcium is an important element in the growth and development of plants and one form of calcium is calcium oxalate. Calcium oxalate has been found in leaf seed, stem material plant tissue culture, fungi and lichen using one or more of the following methods—polarized light microscopy (PLM), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and x-ray diffraction.Two methods are presented here for qualitatively estimating calcium oxalate in dried or fixed tobacco (Nicotiana) leaf from different stalk positions using PLM. SEM, coupled with energy dispersive x-ray spectrometry (EDS), and powder x-ray diffraction were used to verify that the crystals observed in the dried leaf with PLM were calcium oxalate.

Scanning Electron Microscopy and X-Ray Analyses of Dental Tissues from a Hibernator

1976 ◽  
Vol 34 ◽  
pp. 178-179
Author(s):  
M. L. Zimny ◽  
A. C. Haller
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Body Temperature ◽  
Ground Squirrel ◽  
Alveolar Bone ◽  
X Ray ◽  
Dental Tissues ◽  
Bone Minerals ◽  
Apical Tooth ◽  
Scanning Electron

During hibernation the ground squirrel is immobile, body temperature reduced and metabolism depressed. Hibernation has been shown to affect dental tissues varying degrees, although not much work has been done in this area. In limited studies, it has been shown that hibernation results in (1) mobilization of bone minerals; (2) deficient dentinogenesis and degeneration of alveolar bone; (3) presence of calculus and tears in the cementum; and (4) aggrevation of caries and pulpal and apical tooth abscesses. The purpose of this investigation was to study the effects of hibernation on dental tissues employing scanning electron microscopy (SEM) and related x-ray analyses.

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