Zinc Substituted Hydroxyapatite – A Comparison of Modelling and Experimental Data

2008 ◽  
Vol 396-398 ◽  
pp. 729-732 ◽  
Author(s):  
Helen Chappell ◽  
David Shepherd ◽  
Serena Best
Keyword(s):  
Experimental Data ◽  
Experimental Study ◽  
Ab Initio ◽  
Formation Energy ◽  
Room Temperature ◽  
Lattice Parameter ◽  
Experimental Measurements ◽  
Type Ii ◽  
Substitution Site ◽  
Modelling Data

The effect of substitution of zinc into the hydroxyapatite lattice(ZnHA) was evaluated using experimental precipitation studies and with ab initio modelling data. When attempting to introduce zinc into the hydroxyapatite (HA) lattice not all of the zinc is substituted and ICP confirms its presence in the supernatant. Modelling suggests that this is likely to be because of the high formation energy introducing zinc into the pure hydroxyapatite lattice, 4.6 - 4.9eV. In the experimental study it was found that a maximum of 0.61wt% zinc could be substituted into the HA lattice at 10oC with less being substituted at room temperature »22oC. Experimental measurements revealed that the presence of zinc in the lattice decreased the a-lattice parameter and increased the c-lattice parameter. Modelling showed that this was likely to be caused by the movement of the hydroxyl ions away from the c-axis, towards the zinc atoms which were substituted in calcium type II positions. The type II position was shown to be the most stable substitution site.

Experimental study of ultrathin liquid lubrication film thickness at the molecular scale

1997 ◽  
Vol 211 (2) ◽  
pp. 139-150 ◽  
Author(s):  
H Matsuoka ◽  
T Kato
Keyword(s):  
Experimental Data ◽  
Experimental Study ◽  
Film Thickness ◽  
Solid Surface ◽  
Experimental Measurements ◽  
Dynamic Measurements ◽  
Lubrication Film ◽  
Solid Specimen ◽  
Molecular Scale ◽  
New Apparatus

Ultrathin liquid lubrication film thicknesses at the molecular scale are measured by a new apparatus developed by the authors. Mica is used as the solid specimen and octamethylcyclotetrasiloxane (OMCTS), cyclohexane and n-hexadecane are used as liquid specimens. From experimental measurements, discretization of the lubrication film thickness is observed when the thickness is less than about 10 times the molecular diameter of the intervening liquid. Analysis of experimental data shows that the discretization of the lubrication film thickness is due to the solvation force. Dynamic measurements show that the solvation force is almost the same as the non-sliding case and is independent of the sliding speed of the solid surface.

Thermal Conductivity of Nanochanneled Alumina

2000 ◽  
Author(s):  
A. R. Kumar ◽  
D.-A. Achimov ◽  
T. Zeng ◽  
G. Chen
Keyword(s):  
Experimental Data ◽  
Thermal Conductivity ◽  
Experimental Study ◽  
Heat Conduction ◽  
Room Temperature ◽  
Conduction Model ◽  
Heat Conduction Model ◽  
Anisotropic Heat Conduction ◽  
3Ω Technique

Abstract We present an experimental study on the thermal conductivity of anodized alumina with regular nanochannels. Thermal conductivity values in both directions parallel and perpendicular to the nanochannel axis are measured at room temperature using the 3ω technique. An anisotropic heat conduction model is developed to analyze the experimental data.

scholarly journals Experimental study of hygrothermal conditions in a wooden room for numerical comparisons

2021 ◽  
Vol 2069 (1) ◽  
pp. 012209
Author(s):  
C Legros ◽  
A Piot ◽  
M Woloszyn ◽  
M Pailha
Keyword(s):  
Experimental Data ◽  
Experimental Study ◽  
Relative Humidity ◽  
Ventilation Rate ◽  
Experimental Setup ◽  
Experimental Measurements ◽  
Materials Properties ◽  
Numerical Comparisons ◽  
Numerical Tools ◽  
Heat And Moisture

Abstract The use of hygroscopic materials indoors has a significant impact on the hygrothermal balance of a room air. It affects both the temperature and the relative humidity. Numerical tools still lack of accuracy in predicting these parameters and some discrepancies are observed between their predictions and experimental measurements. It may be caused by the model itself or by incorrect inputs data (materials properties, occupancy schedule, ventilation rate, etc…) Therefore, an experimental study has been carried out at the room scale under real climate to obtain an experimental dataset as a basis for numerical comparisons. The hygrothermal parameters of the room air have been measured for different loads while all the inputs (heat and moisture generation, air exchange and materials properties) have been properly quantified. This article presents the experimental setup and some of the experimental data obtained.

scholarly journals Experimental measurements of gravity casting flow

2019 ◽  
Vol 213 ◽  
pp. 02054
Author(s):  
Libor Lobovský ◽  
Tomáš Mandys
Keyword(s):  
Experimental Data ◽  
Surface Tension ◽  
Experimental Investigation ◽  
Physical Properties ◽  
Room Temperature ◽  
Optical Measurement ◽  
Measurement Methods ◽  
Experimental Measurements ◽  
Transparent Material ◽  
Gravity Casting

An experimental investigation of casting processes performed under well controlled laboratory conditions is presented. Casting molds made of transparent material allow for analysis of flow patterns by means of standard optical measurement methods. The tests are carried out for selected highly-viscous Newtonian fluids at room temperature. The physical properties of the test fluids (i.e. viscosity, surface tension and density) are identified. As a result, an extensive set of experimental data is provided.

A Theoretical and Experimental Study of the Chemical Bonding in AgGaS2

1996 ◽  
Vol 453 ◽  
Author(s):  
Alessandra Continenza ◽  
Teresa M. de Pascale ◽  
Franco Meloni ◽  
Marina Serra ◽  
Ali Shaukat ◽  
...  
Keyword(s):  
Experimental Data ◽  
Experimental Study ◽  
Charge Density ◽  
Ab Initio ◽  
Chemical Bond ◽  
Chemical Bonding ◽  
X Ray ◽  
Electronic Distribution ◽  
D Orbitals

AbstractAgGaS2 is a technologically important semiconductor for its large birefringence coefficient. In this work we compare the theoretical ab-initio all-electron FLAPW results with very refined experimental data obtained with accurate X-ray analysis. In particular we focus our attention to the electronic distribution along the significative bonding directions connecting the three different atoms. Furthermore, the charge density contours around Ag provide a clear evidence of the contribution of its d orbitals to the chemical bond.

Evidence for ordered Fe3Ni

1987 ◽  
Vol 45 ◽  
pp. 216-217
Author(s):  
K.B. Reuter ◽  
D.B. Williams ◽  
J.I. Goldstein
Keyword(s):  
Experimental Data ◽  
Martensitic Transformation ◽  
Electron Diffraction ◽  
Room Temperature ◽  
Direct Evidence ◽  
Transformation Product ◽  
Iron Meteorites ◽  
X Ray ◽  
Ni Content ◽  
Temperature Transformation

In the Fe-Ni system, although ordered FeNi and ordered Ni3Fe are experimentally well established, direct evidence for ordered Fe3Ni is unconvincing. Little experimental data for Fe3Ni exists because diffusion is sluggish at temperatures below 400°C and because alloys containing less than 29 wt% Ni undergo a martensitic transformation at room temperature. Fe-Ni phases in iron meteorites were examined in this study because iron meteorites have cooled at slow rates of about 10°C/106 years, allowing phase transformations below 400°C to occur. One low temperature transformation product, called clear taenite 2 (CT2), was of particular interest because it contains less than 30 wtZ Ni and is not martensitic. Because CT2 is only a few microns in size, the structure and Ni content were determined through electron diffraction and x-ray microanalysis. A Philips EM400T operated at 120 kV, equipped with a Tracor Northern 2000 multichannel analyzer, was used.

EXPERIMENTAL STUDY OF THE KINEMATIC PARAMETERS OF MOVEMENT OF CARS FORCED IDLE MOTION

2018 ◽  
pp. 52-57
Author(s):  
Ivelin Kostov
Keyword(s):  
Experimental Data ◽  
Experimental Study ◽  
Experimental Research ◽  
Kinematic Parameters ◽  
Research Results ◽  
Software Product

In the work brought some experimental data of kinematic parameters of movement of cars forced idle, as the software product was used to diagnose 900 ATS, which recorded kinematic parameters of vehicle. On the basis of the conducted experimental research results are shown tabulated and analysed.

Investigation of the V4+-Centre in 6H- and 4H-SIC by the Method of Spectral-Hole Burning

1998 ◽  
Vol 512 ◽  
Author(s):  
C. Hecht ◽  
R. Kummer ◽  
A. Winnacker
Keyword(s):  
Electronic Properties ◽  
Room Temperature ◽  
Hole Burning ◽  
Band Offset ◽  
Spectral Hole Burning ◽  
Type Ii ◽  
Thermally Stable ◽  
Spectral Hole

ABSTRACTIn the context of spectral-hole burning experiments in 4H- and 6H-SiC doped with vanadium the energy positions of the V4+/5+ level in both polytypes were determined in order to resolve discrepancies in literature. From these numbers the band offset of 6H/4H-SiC is calculated by using the Langer-Heinrich rule, and found to be of staggered type II. Furthermore the experiments show that thermally stable electronic traps exist in both polytypes at room temperature and considerably above, which may result in longtime transient shifts of electronic properties.

Configurational Assignment and Conformational Study of Methylglyoxal Bisdimethylhydrazones Derived from the 2-Ethoxypropenal Precursor

2006 ◽  
Vol 59 (3) ◽  
pp. 211 ◽  
Author(s):  
Leonid B. Krivdin ◽  
Lyudmila I. Larina ◽  
Kirill A. Chernyshev ◽  
Natalia A. Keiko
Keyword(s):  
Ab Initio Calculations ◽  
Ab Initio ◽  
Experimental Measurements ◽  
Conformational Study ◽  
Lone Pairs ◽  
Configurational Assignment ◽  
Out Of Plane ◽  
High Level

A configurational assignment of the isomeric methylglyoxal bisdimethylhydrazones derived from the 2-ethoxypropenal precursor has been performed based on experimental measurements and high-level ab initio calculations of 1J(C,C) and 1J(C,H) couplings. The results reveal the marked stereochemical dependence upon the orientation of the lone pairs of both nitrogen atoms in different isomers. Methylglyoxal bisdimethylhydrazone is shown to exist in a mixture of the EE and ZE isomers (ca. 75:25), both of which adopt predominant s-trans conformations with minor (up to 8°) out-of-plane deviations.

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