In this chapter, we will restrict our attention to the ferrites and a few other closely related materials. The great interest in ferrites stems from their unique combination of a spontaneous magnetization and a high electrical resistivity. The observed magnetization results from the difference in the magnetizations of two non-equivalent sub-lattices of the magnetic ions in the crystal structure. Materials of this type should strictly be designated as “ferrimagnetic” and in some respects are more closely related to anti-ferromagnetic substances than they are to ferromagnetics in which the magnetization results from the parallel alignment of all the magnetic moments present. We shall not adhere to this special nomenclature except to emphasize effects, which are due to the existence of the sub-lattices.

Ferromagnetic materials

There is a special reason for reviewing this book at this time: it is the 50th edition of a compendium that is known and used frequently in most chemical and physical laboratories in many parts of the world. Surely, a publication that has been published for 56 years, withstanding the vagaries of science in this century, must have had something to offer. There is another reason: while the book is a standard fixture in most chemical and physical laboratories, including those in medical centers, it is not as frequently seen in the laboratories of physician's offices (those either in solo or group practice). I believe that the Handbook can be useful in those laboratories. One of the reasons, among others, is that the various basic items of information it offers may be helpful in new tests, either physical or chemical, which are continuously being published. The basic information may relate

Handbook of Chemistry and Physics

Electrospinning is a versatile and viable technique for generating ultrathin fibers. Remarkable progress has been made with regard to the development of electrospinning methods and engineering of electrospun nanofibers to suit or enable various applications. We aim to provide a comprehensive overview of electrospinning, including the principle, methods, materials, and applications. We begin with a brief introduction to the early history of electrospinning, followed by discussion of its principle and typical apparatus. We then discuss its renaissance over the past two decades as a powerful technology for the production of nanofibers with diversified compositions, structures, and properties. Afterward, we discuss the applications of electrospun nanofibers, including their use as "smart" mats, filtration membranes, catalytic supports, energy harvesting/conversion/storage components, and photonic and electronic devices, as well as biomedical scaffolds. We highlight the most relevant and recent advances related to the applications of electrospun nanofibers by focusing on the most representative examples. We also offer perspectives on the challenges, opportunities, and new directions for future development. At the end, we discuss approaches to the scale-up production of electrospun nanofibers and briefly discuss various types of commercial products based on electrospun nanofibers that have found widespread use in our everyday life.

Electrospinning and Electrospun Nanofibers: Methods, Materials, and Applications

In this article, several applications of nanomaterials in food packaging and food safety are reviewed, including: polymer/clay nanocomposites as high barrier packaging materials, silver nanoparticles as potent antimicrobial agents, and nanosensors and nanomaterial-based assays for the detection of food-relevant analytes (gasses, small organic molecules and food-borne pathogens). In addition to covering the technical aspects of these topics, the current commercial status and understanding of health implications of these technologies are also discussed. These applications were chosen because they do not involve direct addition of nanoparticles to consumed foods, and thus are more likely to be marketed to the public in the short term.

Applications of nanotechnology in food packaging and food safety: Barrier materials, antimicrobials and sensors

Polymer nanoparticles: Preparation techniques and size-control parameters

Effect of surfactants addition on physical, structure and antimicrobial activity of (Na-CMC/Na–Alg) biofilms

Vicia faba L. Plant was grown in a pot experiment to study the positive role of CaCl 2 on NaCl induced stress in terms of growth parameters, metabolic, cation contents and cell wall degrading enzymes in different plant organs. The salinity treatments were having an osmotic potential of (0.0; -0.23;-0.46; -0.92 and -1.15 MPa), respectively. A hundred mL of 10 mM CaCl 2 were added to the previous concentrations and harvested after 11 weeks old. The data revealed that, NaCl treatments reduced the growth parameters; which most sensitive in root than shoot. Organic cytosolutes were much higher in root than shoot organ except for protein accumulation. The amount of inorganic cytosolutes (Na + and Ca 2+ ) in general increased markedly in shoot than root and vice versa for K + and Mg 2+ . CaCl 2 treatment alone induces these parameters than control one. Mixed salts of NaCL and CaCl 2 positively improve the aforementioned parameters with varying degrees depending on the organs. While root seems to be the more sensitive organ for growth parameters measured, it also seems most accumulator organ than shoot for many metabolites. For the ionic contents, shoot and root varies between the mono and divalent cations. Cell wall degrading enzymes significantly and progressively increased as salinity level of treated plants increased. However, CaCl 2 treatments induced a significant reduction in the activity of these enzymes when compared with their respective NaCL treatments. The ameliorative percentage due to calcium application of stressed faba bean on growth parameters ranges from 17.53 to 79.55 %; for metabolites from 8.69 to 194.91; for ionic status from 9.94 to 56.67 %, and for cell wall degrading enzymes from 16.76 to 39.15 %. These data leads to strongly recommend adding CaCl 2 to saline environment to decrease the deleterious effects of salinity.

/pdf/ameliorative-effects-of-ca-2-on-the-growth-metabolism-2t12kp721e.pdf

Ameliorative effects of Ca 2+ on the growth, metabolism, cationic status and cell wall degrading enzymes of induced salinity stress Vicia faba L.

H3PO4/KOH combined solution is proposed as a new effective activation agent for activated carbon production from rice husk. Several activated carbon samples were produced by using different volumes of the utilized acid and alkali individually, in addition to the combined solution. FTIR results indicated that the mixed agent partially decomposed the chemical compounds on the rice husk char surface, resulting in an increase in the surface area. Moreover, XRD and EDS analyses showed the presence of a considerable amount of amorphous silica. Electrochemical measurements concluded that the volume of the activation agent solution should be optimized for both single and mixed activation agents. Numerically, for 0.3 g treated rice husk char, the maximum specific capacitance was observed at 7, 10 and 14 mL of H3PO4, KOH (3 M) and mixed (1:1 by volume) activation agents, respectively; the determined specific capacitance values were 73.5, 124.2 and 241.3 F/g, respectively. A galvanostatic charging/discharging analysis showed an approximate symmetrical triangular shape with linear voltage versus time profile which indicates very good electrochemical performance as an electrode in the supercapacitors application. The stability of the proposed activated carbon was checked by performing a cyclic voltammetry measurement for 1000 cycles at 2 mV/s and for 30,000 cycles at 10 mV/s. The results indicate an excellent specific capacitance retention, as no losses were observed.

/pdf/h3po4-koh-activation-agent-for-high-performance-rice-husk-1feqshz1.pdf

H3PO4/KOH Activation Agent for High Performance Rice Husk Activated Carbon Electrode in Acidic Media Supercapacitors

Synthesis and characterization of CoMnO nanofibers supported on a graphite disk: Novel strategy for nanofibers immobilization

In this study, a good combination of electrospun poly(caprolactone) nanofibers incorporated with high purity titanium nanoparticles is introduced for hard tissue engineering applications. A simple approach to utilize the colloidal properties of poly(caprolactone) and titanium nanoparticles are exploited to form nanofibers by the simple electrospinning process. The prepared colloidal solutions were characterized using dynamic light scattering and electrophoratic light scattering which indicated unimodal size distribution and negative zeta potential. To investigate the bioactivity of the resultant nanofiber mats, they were incubated in simulated body fluid at 37 °C for 10 days. Field emission scanning electron microscopy in combination with energy-dispersive X-ray spectroscopy indicated that incorporation of titanium strongly activates precipitation of the apatite-like materials from the utilized simulated body fluid. Moreover, in-vivo experiments using experimental dogs revealed that nanofibers ca...

Nasser A.M. Barakat

Papers

Effect of surfactants addition on physical, structure and antimicrobial activity of (Na-CMC/Na–Alg) biofilms

Ameliorative effects of Ca 2+ on the growth, metabolism, cationic status and cell wall degrading enzymes of induced salinity stress Vicia faba L.

H3PO4/KOH Activation Agent for High Performance Rice Husk Activated Carbon Electrode in Acidic Media Supercapacitors

Synthesis and characterization of CoMnO nanofibers supported on a graphite disk: Novel strategy for nanofibers immobilization

Nanobiotechnology approach to fabricate polycaprolactone nanofibers containing solid titanium nanoparticles as future implant materials