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Formation and Biomimetic Deposition of Bone-like Hydroxyapatite on Wollastonite-gypsum Composites

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Journal of Bionic Engineering 2018年第5期15卷 894-906页

作者： Yaser Greish Nuha Attia Abdel-hamid Mourad Department of Chemistry College of Science United Arab Emirates University AI Ain UAE Department of Ceramics National Research Centre Cairo Egypt Department of Mechanical Engineering College of Engineering United Arab Emirates University Al Ain UAE Mechanical Design Department Faculty of Engineering at Mataria Helwan University Cairo Egypt

Bone cements are often used for bone repair and fixation. The main objective of formulating a bone cement is to achieve structure and properties similarity to bone. In addition, bioactivity of a bone cement provides a major advantage that helps achieving better binding and interaction with the surrounding tissues. In the current study, gypsum was used as a matrix for a composite that comprises highly crys- talline prestine and acid-treated wollastonite （CaSiO3） fibers. Composites made by mixing their powder precursors with deionized water at room temperature, were investigated for their composition using X-ray diffraction （XRD） and Thermogravimetric Analysis （TGA）, for their microstructure using Scanning Electron Microscopy （SEM）, for their compressive strengths and modulus of elasticity, and for setting time measurements. In addition, cement composites were evaluated for their preliminary bioactivity in a protein-free Simulated Body Fluid （SBF） for up to 14 days. Results show the improvement of mechanical properties and bioactivity of the composites using acid-treated wollastonite fibers. This was attributed to the formation of hydrated silica layer on the surface of the acid-treated fibers which improved the binding with the gypsum matrix and provided nucleating sites for the deposition of bone-like apatite spherolites from SBF media.

关键词： gypsum wollastonite bone cement biomimetic SBF microstructure

Lithostratigraphy and Microbiostratigraphy of Gadvan and Darian Formations in South Semirom, East of Zagros Basin, South-Central Iran

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Open Journal of Geology 2017年第2期7卷 119-131页

作者： Mohammad Kazem Hamedanian Seyed hamid Vaziri Mahnaz Amir Shakarami Mehran arian Naser Arzani Department of Geology Science and Research Branch Islamic Azad University Tehran Iran Department of Geology North Tehran Branch Islamic Azad University Tehran Iran Department of Geology Payam Noor University Isfahan Iran

This research focuses on the lithostratigraphy and microbiostratigraphy implications of the Gadvan and Darian Formations in a part of Zagros sedimentary basin. The Gadvan and Darian Formations in the study area with a thick-ness of 520 meters consist of gray to green marls and shales, dark-grey limestones and Orbitolina limestone with Late Barremian-Aptian age. According to the lithostratigraphic investigations, the Gadvan and Darian Formations in the study area are subdivided into eleven units. The upper boundary of the Darian Formation with the Kazhdomi Formation and the lower boundary of Gadvan Formation with the Fahliyan Formation are in the form of disconformity. Micropaleontological study of the Gadvan and Dariyan Formations has led to the recognition 20 families, 45 genera, 35 species of benthic foraminifera, 2 genera of pelagic foraminifera and 8 genera and species of the calcareous algae. In this research, three biozones have been recognized by distribution of the larger benthic foraminifera in the Gadvan and Dariyan Formations of the South Semirom, including: 1) Palorbitolina lenticularis-Choffatella decipiens Concurrent Range Zone (middle Late Barremian to early Early Aptian);2) Praeorbitolina cormyi-Orbitolina (Mesorbitolina) lotzei Assemblage Zone (late Early Aptian);3): Orbitolina (Mesorbitolina) texanae-Orbitolina (Mesorbitolina) parva Assemblage Zone (Middle to Late Aptian). Based on the identified foraminifera, the age of the Gadvan and Darian Formations in the study area is assigned to Late Barremian to Aptian.

关键词： Lower Cretaceous Foraminifera Gadvan Darian Biozone Zagros Semirom

Second Order Fluid Glow Discharge Model Sustained by Different Source Terms

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Plasma Science and Technology 2011年第5期13卷 583-590页

作者： D.GUENDOUZ A.hamid A.HENNAD Institute of Maintenance and Industrial Security University of Oran Electrical Engineering Department Oran University of Sciences and Technology

Behavior of charged particles in a DC low pressure glow discharge is studied. The electric properties of the glow discharge in argon, maintained by a constant source term with uni- form electron and ion generation, between two plane electrodes or by secondary electron emission at the cathode, are determined. A fluid model is used to solve self-consistently the first three moments of the Boltzmann equation coupled with the Poisson equation. The stationary spatial distribution of the electron and ion densities, the electric potential, the electric field, and the electron energy, in a two-dimensional （2D） configuration, are presented.

关键词： glow discharge Boltzmann equation Poisson equation electron temperature

Electroencephalography studies of hypoxic ischemia in fetal and neonatal animal models

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Neural Regeneration Research 2020年第5期15卷 828-837页

作者： hamid Abbasi Charles P.Unsworth Department of Engineering Science the University of Auckland

Alongside clinical achievements,experiments conducted on animal models (including primate or non-primate) have been effective in the understanding of various pathophysiological aspects of perinatal hypoxic/ ischemic encephalopathy (HIE).Due to the reasonably fair degree of flexibility with experiments,most of the research around HIE in the literature has been largely concerned with the neurodevelopmental outcome or how the frequency and duration of HI seizures could relate to the severity of perinatal brain injury,following HI *** survey concentrates on how EEG experimental studies using asphyxiated animal models (in rodents,piglets,sheep and non-human primate monkeys) provide a unique opportunity to examine from the exact time of HI event to help gain insights into HIE where human studies become difficult.

关键词： animal models automatic detection clinical EEG fetal HIE hypoxic-ischemic encephalopathy neonatal non-human primates review seizure

Development of fragility curves by incorporating new spectral shape indicators and a weighted damage index:case study of steel braced frames in the city of Mashhad,Iran

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Earthquake Engineering and Engineering Vibration 2017年第2期16卷 383-395页

作者： hamid Kazemi Mohsen Ghafory-Ashtiany Alireza Azarbakht Department of Civil Engineering Science and Research Branch Islamic Azad University Tehran Iran International Institute of Earthquake Engineering and Seismology (IIEES) Tehran Iran Department of Civil Engineering Faculty of Engineering Arak University Arak Iran

In this study, strong ground motion record （SGMR） selection based on Eta （~/） as a spectral shape indicator has been investigated as applied to steel braced flame structures. A probabilistic seismic hazard disaggregation analysis for the definition of the target Epsilon （ε） and the target Eta （η） values at different hazard levels is presented, taking into account appropriately selected SGMR＇s. Fragility curves are developed for different limit states corresponding to three representative models of typical steel braced frames having significant irregularities in plan, by means of a weighted damage index. The results show that spectral shape indicators have an important effect on the predicted median structural capacities, and also that the parameter r/is a more robust predictor of damage than searching for records with appropriate c values.

关键词： vulnerability spectral shape indicator incremental dynamic analysis damage index hazard disaggregation record selection

Study of effective parameters for enhancement of methane gas production from natural gas hydrate reservoirs

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Green Energy & Environment 2019年第4期4卷 453-469页

作者： hamid Aghajari Moien Habibi Moghaddam Mehdi Zallaghi Azad University Omidiyeh BranchIran Isfahan Oil Refinery Co. Iran Science and Research Azad University of Tehran Iran Tehran Petroleum Research Center Petroleum University of TechnologyIran

Natural gas hydrate resources have become the major source of energy in the second half of 21st *** production and fluid behavior in natural gas hydrate reservoirs are different from conventional *** are three major methods for methane decomposition such as depressurization,thermal stimulation and inhibitor ***,CO2 substitution can also be introduced as an alternative method to inject in sediments containing gas *** these methods tend to imbalance equilibrium condition via temperature and pressure variation in order to fulfill hydrate decomposition *** study aims to simulate depressurization method for gas production from a hydrate gas bearing ***,a sensitivity analysis of reservoir parameters includes porosity,permeability,hydrate saturation,hydrate thickness layer;pressure and temperature of single well hydrate model were investigated to determine how these parameters impact on gas *** show that depressurization is an efficient method for gas production from hydrate bearing *** sensitivity analysis,it has been concluded that if properties of a hydrate layer such as porosity and permeability become greater,methane production will be increased ***,results investigate that the rate of hydrate dissociate is strongly dependent on pressure reduction,and it has a reverse relationship with bottomhole pressure and reservoir temperature.

关键词： Gas hydrate Depressurization Sensitivity analysis Simulation study Hydrate dissociation Methane formation Thermodynamic equilibrium

Bifurcation in a 3-DOF Airfoil with Cubic Structural Nonlinearity

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Chinese Journal of Aeronautics 2011年第3期24卷 265-278页

作者： Saied IRANI hamid SARRAFzadEH Mohammad Reza AMOOZGAR Department of Aerospace Engineering K.N.Toosi University of Technology

Limit cycle oscillations （LCOs） as well as nonlinear aeroelastic analysis of a 3-DOF aeroelastic airfoil motion with cubic restoring moments in the pitch degree of freedom are investigated. Aeroelastic equations of an airfoil with control surface in an incompressible potential flow are presented in the time domain. The harmonic balance （HB） method is utilized to calculate the LCO frequency and amplitude for the airfoil. Also the semi-analytical method has revealed the presence of stable and unstable limit cycles, along with stability reversal in the neighborhood of a Hopf bifurcation. The system response is determined by nu- merically integrating the governing equations using a standard Runge-Kutta algorithm and the obtained results are compared with the HB method. Also the results by the third order HB （HB3） method for control surface are consistent with the other numerical solution. Finally, by combining the numerical and the HB methods, types of bifiarcation, be it supercritical, subcritical, or diver- gent flutter area are identified.

关键词： flutter bifurcation cubic nonlinearity limit cycle oscillations harmonic balance method

An accurate model for the thin film flow

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Acta Mechanica Sinica 2008年第4期24卷 375-380页

作者： hamid Ait Abderahmane Georgios H.Vatistas Department of Mechanical and Industrial Engineering Concordia University 1455 de Maisonneuve Blvd West Montreal OC H3G 1M8 Canada

This paper deals with the linear stability of a liquid film flowing down an inclined plane. The Navier-Stokes equations were reduced into four evolution equations that describe the development of the film depth, the flow rate, the free surface velocity, and the wall shear stress, using the Karman-Polhausen boundary layer integral method. Thus, we were able to determine the stability threshold and approach well the critical wave number for long waves. The obtained results were found to be in good agreement with the experiments of Liu et al.

关键词： Liquid film Linear stability Flow model

Fabrication and characterization of nanocrystalline Al/Al_(12)(Fe,V)_3Si alloys by consolidation of mechanically alloyed powders

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International Journal of Minerals,Metallurgy and Materials 2014年第7期21卷 711-719页

作者： hamid Ashrafi Rahmatollah Emadi Mohammad Hosein Enayati Department of Materials Engineering Isfahan University of Technology

The aim of this study was to produce bulk nanocrystalline Al/Al12（Fe,V）3Si alloys by mechanical alloying （MA） and subsequent hot pressing （HP） of elemental powders. A nanostructured Al-based solid solution was formed by MA of elemental powders for 60 h. After HP of the as-milled powders at 550℃ for 20 min, the Al12（Fe,V）3Si phase was precipitated in a nanocrystalline Al matrix. Scanning electron microscopy （SEM） images of the bulk samples represented a homogeneous and uniform microstructure that was superior to those previously obtained by rapid solidification-powder metallurgy （RS-PM）. Nanostructured Al-8.5Fe-1.3V-1.7Si and Al-11.6Fe-1.3V-2.3Si alloys ex-hibited high HV hardness values of～205 and～254, respectively, which are significantly higher than those reported for the RS-PM counter-parts.

关键词： aluminum alloys nanostructured materials mechanical alloying hot pressing hardness