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

In this work, a smart epoxy coating was applied based on encapsulation of 3,4΄-dihydro-3-[2΄-mercaptothiazolidine]indol-2-one (DMI) inhibitors to halloysite nanotubes (HNTs) as nanocontainer for corrosion inhibition of API 5L Grade B carbon steel in 3.5% NaCl solution.a#13; Transmission Electron Microscope (TEM) and Brunauer–Emmett–Teller (BET) analysis methods were used to confirm the encapsulation of HNTs with DMI. Layer-by-Layer (LbL) deposition of polyelectrolytes (Branched Polyethylenimine (BPEI) and Poly (ethylene-co-acrylic acid) (PEAA)) on HNTs was validated by zeta potential test. Releasing rate of the inhibitors in various pH conditions were characterized by UV-visible spectroscopy. Electrochemical impedance spectroscopy (EIS), Tafel polarization and salt spray tests were used to evaluate the active anticorrosion ability of 1, 2.5 and 5 wt% of HNTs and DMI-loaded HNTs epoxy coatings. In comparison with blank epoxy coating, higher value of charge transfer resistance, lower value of double layer capacitance (constant phase element) in EIS results and decreasing the density of corrosion current in Tafel curves showed anticorrosive performance of the smart coatings. 2.5% DMI-loaded HNTs coating showed significant effect on corrosion protection of carbon steel samples and was introduced as optimum weight percentage.

https://iopscience.iop.org/article/10.1088/2053-1591/ab3f12/pdf

Investigation of loaded halloysite nanotubes with novel inhibitor as a smart anticorrosion epoxy coating

In this study, nanocrystalline Ni0·64Zn0·36Fe2O4 powders were prepared using a planetary ball mill. The evolution of the microstructure and magnetic properties during the milling were studied by X-ray diffraction technique, scanning electron microscopy, transmission electron microscopy and vibrating sample magnetometre. It is revealed from the results of the phase analysis that nanocrystalline Ni0·64Zn0·36Fe2O4 ferrite with average crystallite size of 6·18 nm and non-uniform lattice strain of 0·33% has been formed after 60 h of milling time. A progressive increase of saturation magnetisation and a dramatic decrease in coercivity were also observed with increasing milling time.

Structure and magnetic properties of nanocrystalline Ni0·64Zn0·36Fe2O4 powders prepared by ball milling

Development and Application of a Pressure Systems Integrity Management Strategy through Risk Based Inspection Audits in Abadan Refinery

Pattern formation and geometry of the manifold

In this research two different paths were used to cabothermic reduction of MoO3. In the first and second path, as received MoO3 and graphite with stoichiometric ratios were mixed and mechanically activated at 5, 10, 15 and 24 h and heating by microwave oven (first path) and furnace at 700 and 1000 °C in second path. The XRD results of activated samples before heating showed that, MoO2 was produced in the planetary ball mill after 5 h milling and don't change to another phase during milling up to 24 h. the SEM and XRD results in first and second path showed that the final product was molybdenum carbide but in the non-activated samples the final products were molybdenum carbide and unreacted MoO2. The practical efficiency calculations in first and second method showed that heating of samples by microwave radiation and mechanical activation increase the practical efficiency and decrease the sublimation of molybdenum trioxide. The TGA analysis of non-activated MoO3+ C mixture indicated that the reduction goes with three steps but in the 24 h activated sample, it was seen that the reduction goes with one peak. In other words, the first and second peaks in non-activated sample were not detected in the activated sample that increases the practical efficiency due to prevent the sublimation of MoO3

Sirus Javadpour

Papers

Investigation of loaded halloysite nanotubes with novel inhibitor as a smart anticorrosion epoxy coating

Structure and magnetic properties of nanocrystalline Ni0·64Zn0·36Fe2O4 powders prepared by ball milling

Development and Application of a Pressure Systems Integrity Management Strategy through Risk Based Inspection Audits in Abadan Refinery

Pattern formation and geometry of the manifold

Effect of microwave radiation and mechanical activation on the Carbothermic reduction of molybdenum trioxide: Improving the practical efficiency