The Importance of Intrafibrillar Mineralization of Collagen on the Mechanical Properties of Dentin

2003 ◽  
Vol 82 (12) ◽  
pp. 957-961 ◽  
Author(s):  
J.H. Kinney ◽  
S. Habelitz ◽  
S.J. Marshall ◽  
G.W. Marshall
Keyword(s):  
Mechanical Properties ◽  
Indentation Modulus ◽  
Restorative Dentistry ◽  
Mineral Concentration ◽  
Dry Conditions ◽  
Hardness Scale ◽  
Altered Form ◽  
Mineral Concentrations ◽  
Measured Hardness

It is widely held that the hardness and modulus of dentin increase in proportion to the mineral concentration. To test this belief, we measured hardness and modulus of normal dentin and an altered form of dentin without gap-zone mineralization in wet and dry conditions by AFM nanoindentation to determine if the modulus and hardness scale linearly with mineral concentration. Mineral concentrations in the mid-coronal location of the normal and altered dentins were 44.4 vol% and 30.9 vol%, respectively. Surrounding the pulp of the altered dentin was a region of higher mineralization, 40.5 vol%. The indentation modulus of normal dentin was 23.9 (SD = 1.1) GPa dry and 20.0 (SD = 1.0) GPa wet. In mid-coronal regions of the altered dentin, the indentation modulus was 13.8 (SD = 2.0) GPa dry and 5.7 (SD = 1.4) GPa wet. In the more mineralized regions of the altered dentin, the modulus was 20.4 (SD = 1.8) GPa dry and 5.3 (SD = 0.8) GPa wet; the properties of the altered wet dentin did not correlate with mineral concentration. The results of this study raise doubt as to whether mineral concentration alone is a sufficient endpoint for assessing the success or failure of remineralization approaches in restorative dentistry.

scholarly journals Effects of water absorption on the mechanical properties of hybrid natural fibre/phenol formaldehyde composites

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Sekar Sanjeevi ◽  
Vigneshwaran Shanmugam ◽  
Suresh Kumar ◽  
Velmurugan Ganesan ◽  
Gabriel Sas ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Impact Strength ◽  
Water Absorption ◽  
Hybrid Composites ◽  
Phenol Formaldehyde ◽  
Natural Fibre ◽  
The Other ◽  
Fibre Reinforcement ◽  
Dry Conditions

AbstractThis investigation is carried out to understand the effects of water absorption on the mechanical properties of hybrid phenol formaldehyde (PF) composite fabricated with Areca Fine Fibres (AFFs) and Calotropis Gigantea Fibre (CGF). Hybrid CGF/AFF/PF composites were manufactured using the hand layup technique at varying weight percentages of fibre reinforcement (25, 35 and 45%). Hybrid composite having 35 wt.% showed better mechanical properties (tensile strength ca. 59 MPa, flexural strength ca. 73 MPa and impact strength 1.43 kJ/m2) under wet and dry conditions as compared to the other hybrid composites. In general, the inclusion of the fibres enhanced the mechanical properties of neat PF. Increase in the fibre content increased the water absorption, however, after 120 h of immersion, all the composites attained an equilibrium state.

Tissue level mechanical properties of cortical bone in skeletally immature and mature dogs

2009 ◽  
Vol 22 (03) ◽  
pp. 210-215 ◽  
Author(s):  
C.A. Phillips ◽  
S.A. Fernandez ◽  
Y. Li ◽  
S.S. Huja
Keyword(s):  
Mechanical Properties ◽  
Cortical Bone ◽  
Tissue Level ◽  
Mechanical Tests ◽  
Indentation Modulus ◽  
Skeletally Immature ◽  
Beagle Dogs ◽  
Cross Sectional ◽  
Specimen Holder ◽  
Immature Group

Summary Objectives: The purpose of this study was to quantify the tissue level mechanical properties of cortical bone of skeletally immature (~five-month-old) Beagle dogs and compare them to data from mature dogs measured in a previous study. Methods: Eight femoral cross sectional specimens (two bone sections / dog) were obtained from four skeletally immature dogs. A pair of calcein bone labels were administered intravenously to the dogs to mark sites of active mineralization prior to euthanasia. Prepared bone specimens were placed in a nanoindenter specimen holder and the previously identified calcein labelled osteons were located. Labelled (n = 128) and neighbouring unlabelled (n = 127) osteons in skeletally immature femurs were examined by instrumented indentation testing. Indents were made to a depth of 500 nm at a loading rate of 10 nm/s. Indentation modulus (IM) and hardness (H) were obtained. Results: The overall IM of the cortical bone in the skeletally mature groups was significantly greater than in the immature group (p = 0.0011), however overall H was not significantly different. The differences between the groups in IM were significant for the unlabelled osteons (p = 0.001), but not for the labelled osteons (p = 0.56). Conclusion: There are differences in the IM of unlabelled osteons in skeletally immature and mature groups of Beagle dogs. In contrast to whole bone mechanical tests, where there are obvious differences between growing and mature bones, there are only small differences in the micro-mechanical properties.

Mineral concentration dependent modulation of mechanical properties of bone-inspired bionanocomposite scaffold

2011 ◽  
Vol 99 (1) ◽  
pp. 013702 ◽  
Author(s):  
Abhijit Biswas ◽  
Timothy C. Ovaert ◽  
Constance Slaboch ◽  
He Zhao ◽  
Ilker S. Bayer ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Mineral Concentration

scholarly journals Application of the nanoindentation method in assessing of properties of cement composites modified with silica-magnetite nanostructures

2018 ◽  
Vol 163 ◽  
pp. 02002 ◽  
Author(s):  
Elzbieta Horszczaruk ◽  
Roman Jedrzejewski ◽  
Jolanta Baranowska ◽  
Ewa Mijowska
Keyword(s):  
Mechanical Properties ◽  
Magnetite Nanoparticles ◽  
Positive Influence ◽  
Cement Matrix ◽  
Core Shell ◽  
Indentation Modulus ◽  
Cement Composites ◽  
Interfacial Zone ◽  
Berkovich Indenter ◽  
The Core

The results of investigation of the cement composites modified with 5% of silica-magnetite nanostructures of the core-shell type are presented in the paper. The nanoindentation method employing three-sided pyramidal Berkovich indenter was used in the research. The mechanical properties and microstructure of the modified cement composites were evaluated on the basis of the values of hardness and indentation modulus measured inside the cement matrix and in the aggregate-paste interfacial zone. The results were compared with those obtained for the reference composites without nanostructures. The positive influence of the presence of silica-magnetite nanoparticles on the tested properties was found out.

Effects of dynamic indentation on the mechanical response of materials

2008 ◽  
Vol 23 (6) ◽  
pp. 1604-1613 ◽  
Author(s):  
M.J. Cordill ◽  
N.R. Moody ◽  
W.W. Gerberich
Keyword(s):  
Thin Films ◽  
Mechanical Properties ◽  
Mechanical Response ◽  
Length Scale ◽  
Polycrystalline Nickel ◽  
Dynamic Indentation ◽  
Crystalline Materials ◽  
Fused Quartz ◽  
Hardness Values ◽  
Measured Hardness

Dynamic indentation techniques are often used to determine mechanical properties as a function of depth by continuously measuring the stiffness of a material. The dynamics are used by superimposing an oscillation on top of the monotonic loading. Of interest was how the oscillation affects the measured mechanical properties when compared to a quasi-static indent run at the same loading conditions as a dynamic. Single crystals of nickel and NaCl as well as a polycrystalline nickel sample and amorphous fused quartz and polycarbonate have all been studied. With respect to dynamic oscillations, the result is a decrease of the load at the same displacement and thus lower measured hardness values of the ductile crystalline materials. It has also been found that the first 100 nm of displacement are the most affected by the oscillating tip, an important length scale for testing thin films, nanopillars, and nanoparticles.

scholarly journals Survey of fruit nutrient removal by mango (Mangifera indica L.) cultivars for the export market in various producing regions of Mexico

2019 ◽  
Vol 37 (4) ◽  
pp. 437
Author(s):  
Adriana Mellado-Vázquez ◽  
Samuel Salazar-García ◽  
Ricardo Goenaga ◽  
Alfredo López-Jiménez
Keyword(s):  
Nutrient Removal ◽  
Mangifera Indica ◽  
Export Market ◽  
Mineral Concentration ◽  
Mango Fruit ◽  
Physiological Maturity ◽  
Production Region ◽  
Thin Slices ◽  
Forced Air ◽  
Mineral Concentrations

In Mexico there are more than 201 400 ha grown with different mango (Mangifera indica L.) cultivars. This may cause variations in mineral requirement, fruit mineral concentrations and nutrient removal. The objective of this research was to make a survey of mineral concentration in fruit tissues and calculate nutrient removal by fruit tissues during harvest of the most important mango cultivars (Ataulfo, Kent and Tommy Atkins) from several production regions (Campeche, Chiapas, Oaxaca, Nayarit, and Sinaloa) of Mexico. Fruit at physiological maturity were harvested from commercial mango orchards and concentration of nitrogen (N), phosphorus (P), potassium (K), calcium (Ca), magnesium (Mg), sulfur (S), iron (Fe), copper (Cu), manganese (Mn), zinc (Zn) and boron (B) was determined for skin, mesocarp, endocarp, and seed tissues. Each tissue was cut into thin slices and they were dehydrated in a forced air oven at 70 °C, after that, were pulverized and they were analyzed: nitrogen by semi-microKjeldahl digestion, phosphorus with the ascorbic acid method and the other nutrients with atomic absorption. The removal of nutrients was calculated considering the weight of the fruit and the content of nutrients in each tissue. Signif icant differences in the concentration of N, K, Mg, and Zn were found among cultivars and tissues. Concentration of P, S, Cu, and Mn in the skin, Ca, Cu, and Mn in the mesocarp, Ca, S, Mn, and B in endocarp, and S, Fe, and Mn in the seed were not affected by mango cultivar. Production region affected concentration of minerals in ‘Ataulfo’ fruit more than in ‘Tommy Atkins’ and ‘Kent’. Nutrient removal by mango fruit tissues was little affected in cvs. Ataulfo, Tommy Atkins and Kent. The regions with the greatest nutrient removal were Oaxaca, Campeche and Sinaloa for ‘Ataulfo’, ‘Tommy Atkins’ and ‘Kent’, respectively.

Mechanical and Tribological Properties of W(100-x)%Cx% Coatings Deposited by DC Magnetron Sputtering

2015 ◽  
Vol 642 ◽  
pp. 184-189
Author(s):  
Yan Liang Su ◽  
Yueh Feng Lin
Keyword(s):  
Mechanical Properties ◽  
Wear Resistance ◽  
Magnetron Sputtering ◽  
X Ray Diffraction ◽  
Mechanical And Tribological Properties ◽  
Unbalanced Magnetron Sputtering ◽  
Unbalanced Magnetron ◽  
Pin On Disc ◽  
Dry Conditions ◽  
Coating Microstructure

W(100-x)%Cx% coatings with different tungsten and carbon contents were deposited by unbalanced magnetron sputtering. The microstructures and mechanical properties of the W(100-x)%C x% coatings was characterized by scanning electron microscope (SEM), X-ray diffraction (XRD), nanoindentation and adhesion testing techniques. The tribological performance of the coatings was investigated using a pin-on-disc trobometer under dry conditions. Experimental results indicated that coating microstructure, mechanical properties and wear resistance varied according to the tungsten and carbon contents of the coatings. The W72%C28% coating had the highest hardness/elastic modulus (H/E) ratio. In the ball-on-disc wear tests, it was found that the W72%C28% coating exhibited the best wear resistance.

Mechanical Properties of Fired-Clay Brick Masonry Models in Moist and Dry Conditions

2014 ◽  
Vol 624 ◽  
pp. 307-312 ◽  
Author(s):  
Cristina Gentilini ◽  
Elisa Franzoni ◽  
Gabriela Graziani ◽  
Simone Bandini
Keyword(s):  
Mechanical Properties ◽  
Mechanical Performance ◽  
Point Of View ◽  
Shear Behaviour ◽  
Masonry Buildings ◽  
Masonry Structures ◽  
Clay Brick ◽  
Clay Bricks ◽  
Dry Conditions ◽  
Rising Damp

Rising damp is one of the main issues affecting masonry buildings. However, its consequences on the mechanical performance of masonry structures are not so largely explored. In this paper, the compressive and shear behaviour of masonry triplets, manufactured with solid fired-clay bricks and cement-based mortar, is investigated in dry and moist conditions. The results are interpreted on the basis of the features of the single materials, from both a mechanical and microstructural point of view.

Effect of Crystallographic Orientation on Nanoindentation Response of Fe3Si Single-Crystals

2018 ◽  
Vol 784 ◽  
pp. 44-48 ◽  
Author(s):  
Jaroslav Čech ◽  
Petr Haušild ◽  
Aleš Materna
Keyword(s):  
Mechanical Properties ◽  
Finite Element ◽  
Shear Stress ◽  
Contact Area ◽  
Measured Data ◽  
Deformation Mechanisms ◽  
Spherical Indentation ◽  
Indentation Modulus ◽  
Slip Systems ◽  
Correct Interpretation

Deformation mechanisms and mechanical properties of Fe3(wt.%)Si single crystal in two different orientations were investigated by spherical indentation. For correct interpretation of measured data and better understanding of the deformation mechanisms under the contact area, finite element simulations were carried out and resolved shear stress in available slip systems was computed. Pop-in behavior, differences in hardness, indentation modulus and shapes of residual imprints were observed and associated with different activation of slip.

Effect of Different Factors on Measured Values of Indentation Hardness of Interstitial Free Steel by Depth Sensing Indentation

2018 ◽  
Vol 784 ◽  
pp. 49-54
Author(s):  
Peter Burik ◽  
Ladislav Pešek ◽  
Zuzana Andršová ◽  
Pavel Kejzlar
Keyword(s):  
Mechanical Properties ◽  
Sample Surface ◽  
Indentation Hardness ◽  
Indentation Modulus ◽  
Interstitial Free ◽  
Depth Sensing ◽  
Multiphase Materials ◽  
Material Characteristics ◽  
Straightforward Solution ◽  
Characterization Of Materials

Nanomechanical testing using depth sensing indentation (DSI) provides a straightforward solution for quantitatively characterizing each of phases in microstructure because it is very powerful technique for characterization of materials in small volumes. Measuring the local properties (indentation hardness HIT, indentation modulus EIT, indentation energy: total Wtotal, elastic Welast, plastic Wplast) of each microstructure component separately in multiphase materials gives information that is valuable for the development of new materials and for modelling. The mechanical properties of materials measured by DSI are affected by the experimental procedure, by the measurement conditions and factors which result from the material characteristics and device construction. We have to determine the effect of individual factors on the measurement in order to reach the repeatability and to allow the comparing the mechanical properties of the material. The aim of this investigation is to determine the measurement factors that affect indentation hardness of individual microstructural components and global mechanical properties of thin steel sheets. We investigated the factors which result from the material characteristics (crystallographic orientation of grain, grain boundary and anisotropy), preparation of the sample surface (roughness of sample surface) and method of measurement (pile-up, ISE).

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