Hexagonal ferrites: A review of the synthesis, properties and applications of hexaferrite ceramics

In order to enable optical systems to operate with a high degree of compactness and reliability it is necessary to combine large number of optical functions in small monolithic structures. A development, somewhat reminiscent of that that took place in Integrated Electronics, is now beginning to take place in optics. The initial challenge in this emerging field, known appropriately as "Integrated Optics", is to demonstrate the possibility of performing basic optical functions such as light generation, coupling, modulation, and guiding in Integrated Optical configurations. The talk will review the main theoretical and experimental developments to date in Integrated Optics. Specific topics to be discussed include: Material considerations, guiding mechanisms, modulation, coupling and mode losses. The fabrication and applications of periodic thin film structures will be discussed.

Integrated optics

Electrophoretic deposition (EPD) is attracting increasing attention as an effective technique for the processing of biomaterials, specifically bioactive coatings and biomedical nanostructures. The well-known advantages of EPD for the production of a wide range of microstructures and nanostructures as well as unique and complex material combinations are being exploited, starting from well-dispersed suspensions of biomaterials in particulate form (microsized and nanoscale particles, nanotubes, nanoplatelets). EPD of biological entities such as enzymes, bacteria and cells is also being investigated. The review presents a comprehensive summary and discussion of relevant recent work on EPD describing the specific application of the technique in the processing of several biomaterials, focusing on (i) conventional bioactive (inorganic) coatings, e.g. hydroxyapatite or bioactive glass coatings on orthopaedic implants, and (ii) biomedical nanostructures, including biopolymer–ceramic nanocomposites, carbon nanotube coatings, tissue engineering scaffolds, deposition of proteins and other biological entities for sensors and advanced functional coatings. It is the intention to inform the reader on how EPD has become an important tool in advanced biomaterials processing, as a convenient alternative to conventional methods, and to present the potential of the technique to manipulate and control the deposition of a range of nanomaterials of interest in the biomedical and biotechnology fields.

https://royalsocietypublishing.org/doi/pdf/10.1098/rsif.2010.0156.focus

Electrophoretic deposition of biomaterials

With an ageing population, war, and sports related injuries there is an ever-expanding requirement for hard tissue replacement such as bone. Engineered artificial scaffold biomaterials with appropriate mechanical properties, surface chemistry and surface topography are in a great demand for enhancing cell attachment, cell growth and tissue formation at such defect sites. Most of these engineering techniques are aimed at mimicking the natural organization of the bone tissues and thereby create a conducive environment for bone regeneration. As the interaction between the cells and tissues with biomaterials at the tissue–implant interface is a surface phenomenon, surface properties play a major role in determining both the biological response to implants and the material response to the physiological condition. Hence surface engineering of biomaterials is aimed at modifying the material and biological responses through changes in surface properties while still maintaining the bulk mechanical properties of the implant. Therefore, there has been a great thrust towards development of Ca–P-based surface coatings on various metallic and nonmetallic substrates for load bearing implant applications such as hip joint prosthesis, knee joint prosthesis and dental implants. Typical coating methodologies like ion beam assisted deposition, plasma spray deposition, pulsed laser physical vapor deposition, magnetron sputtering, sol–gel derived coatings, electrodeposition, micro-arc oxidation and laser deposition are extensively studied at laboratory scale. In the present article, attempts are made to give an overview of the basic principles behind the coating techniques as well as advantageous features such as bioactivity and biocompatibility associated with these coatings. A strong emphasis will be given on laser-induced textured and bioactive coatings obtained by the author's research group [A. Kurella, N.B. Dahotre, Journal of Biomedical Applications 20 (2005) 5–50; A. Kurella, N.B. Dahotre, Acta Biomaterialia 2 (2006) 677–688; A. Kurella, N.B. Dahotre, Journal of Minerals, Metals and Materials Society (JOM) 58 (2006) 64–66; A. Kurella, N.B. Dahotre, Journal of Materials Science: Materials in Medicine 17 (2006) 565–572; P.G. Engleman, A. Kurella, A. Samant, C.A. Blue, N.B. Dahotre, Journal of Minerals, Metals and Materials Society (JOM) 57 (2005) 46–50; R. Singh, A. Kurella, N.B. Dahotre, Journal of Biomaterials Applications 21 (2006) 46–72; S.R. Paital, N.B. Dahotre, Biomedical Materials 2 (2007) 274–281; S.R. Paital, N.B. Dahotre, 2009, Acta Biomaterialia, doi:10.1016/j.actbio.2009.03.004 ; R. Singh, N.B. Dahotre, Journal of Materials Science: Materials in Medicine 18 (2007) 725–751.]. Since cells are sensitive to topographical features ranging from mesoscale to nanoscale, formation of these features by both pulsed and continuous wave Nd:YAG laser system will be highlighted. This can also be regarded as advancement towards third generation biomaterials which are bioinert, bioactive and which once implanted will stimulate cell adhesion, proliferation and growth at the interface. Further, an overview of various bio-implants and bio-devices and materials used for these kinds of devices, performance factors such as mechanical and corrosion behavior and surface science associated with these materials are also explained. As the present article is aimed at describing the multidisciplinary nature of this exciting field it also provides a common platform to understand this subject in a simple way for students, researchers, teachers and engineers in the fields ranging from medicine, dentistry, biology, materials science, biomedicine, biomechanics to physics.

Calcium phosphate coatings for bio-implant applications: Materials, performance factors, and methodologies

Friction stir welding/processing of metals and alloys: A comprehensive review on microstructural evolution

The wear resistance and corrosion behavior of titanium and 316L stainless steel were studied after depositing a composite coating of zirconia and hydroxyapatite using the cathodic plasma electrolytic deposition technique. No sign of adhesive wear was observed on coated samples due to the unique surface morphology of the treated samples, after a pin on disk wear test in Ringer's solution. The average values of friction coefficient for treated titanium and steel samples were observed to be 0.2 which exhibited a decrease of about 4 fold for titanium and 7 fold for steel with respect to the substrates. As a result of potentiostatic cyclic tests in Ringer's solution the corrosion current density of coated steel (2.47 × 10−10 A cm−2) was found to be much lower than for the steel substrate (1.87 × 10−7 A cm−2), treated and untreated Ti (6.60 × 10−6, 4.17 × 10−7 A cm−2), indicated the increase in corrosion resistance of steel and decrease of it for titanium after coating.

Study of wear and corrosion behavior of cathodic plasma electrolytic deposition of zirconia–hydroxyapatite on titanium and 316L stainless steel in Ringer's solution

Natural hydroxyapatite has been electrophoretically deposited on medical grade 316L stainless steel. Stable suspensions were prepared by mixing 40 g/L milled natural hydroxyapatite powder in isopropyl alcohol and stabilized by polyethylenimine as dispersing agent and binder. The stability of suspensions was investigated by measuring zeta potential. It was found here that the suspension which was stabilized with 4 g/L polyethylenimine revealed a high value of zeta potential and stability. Deposition was achieved on the cathode at constant voltages of 30, 60, and 90 V for 1 to 5 minutes. After deposition, the samples were dried at room temperature for 24 hours and deposition weight, roughness, and thickness of the coatings were measured. The surface morphology of the coated samples was studied by a scanning electron microscope. The results of the electrophoretic deposition process showed that the sample coated at 60 V and 3 minutes led to an adherent, continuous, and crack-free coating. The coating efficiency and thickness increased with increasing deposition time and yielded to saturation at the constant applied voltage. Also, the current density decreased and yielded to saturation at the constant applied voltage during electrophoretic deposition.

Electrophoretic Deposition of Natural Hydroxyapatite

Background: Today, the effects of environmental pollution on human life and human needs, which
reduces the level of community health caused by traffic noise in large cities, are clearly visible by creating
irritation and pathogenic conditions. The aim of this study was to assess the risk of noise pollution
resulted from central traffic in Shiraz by analyzing its indicators and related components.
Methods: By specifying the high traffic jam in Shiraz, the sound and its frequency in 156 points of the
city were analyzed using a sound analyzer (Tes-1358C model). The sound pressure levels (LA and LP)
and the one and one-third octave band were continuously measured in A and C networks. Then, data
were extracted and analyzed using Excel 2016 and Minitab 18.1. Eventually, phon and sone indexes
were calculated for the heavy traffic jam in some of the central streets of Shiraz and the results were
statistically calculated and their charts were prepared with comfort disturbance ranges.
Results: The highest harmful frequency of traffic in Shiraz was 50 Hz and 83.3 dB. The sound pressure
level ranged from 70 to 92.7 dB in network A and 87.8 dB in network C. The maximum sound level was
87 phon and the maximum sone was 26 at 14 stations.
Conclusion: According to the results, the sound pressure levels exceeded the environmental standards
of Iran and the values of phon and sone were higher than the standard of comfort at night and day.
Keywords: Noise pollution, Environmental pollution, Loudness perception, Health risk assessment,
Shiraz.

Risk assessment of noise pollution by analyzing the level of sound loudness resulting from central traffic in Shiraz

/pdf/pegylated-superparamagnetic-magnetite-nanoparticles-for-4ziu5iqv5h.pdf

PEGylated superparamagnetic magnetite nanoparticles for magnetic fluid hyperthermia therapy

FeNi-based alloys are commonly used as soft magnetic materials, exhibiting high permeability, low coercivity and high saturation magnetization. The present study is focused on the effect of the milling speed (vial and disc rotation speed) on the magnetic properties of nanocrystalline Fe-45 wt. % Ni powders. The phase analysis and the structural properties were characterized by the use of X-ray diffraction. Structural parameters including lattice parameter, crystalline size and lattice strain were obtained from Rietveld's powder structure refinement analysis of X-ray powder diffraction data. The magnetic measurements were performed, using a vibration sample magnetometer (VSM) at room temperature. The results showed that the higher milling speed leads to larger lattice parameter, lower crystalline size, higher saturation magnetization and lower coercivity of the investigated system.

https://iopscience.iop.org/article/10.1088/1742-6596/153/1/012051/pdf

Sirus Javadpour

Papers

Study of wear and corrosion behavior of cathodic plasma electrolytic deposition of zirconia–hydroxyapatite on titanium and 316L stainless steel in Ringer's solution

Electrophoretic Deposition of Natural Hydroxyapatite

Risk assessment of noise pollution by analyzing the level of sound loudness resulting from central traffic in Shiraz

PEGylated superparamagnetic magnetite nanoparticles for magnetic fluid hyperthermia therapy

The effect of milling speed on the magnetic properties of mechanically alloyed Fe-45%Ni powders