Nanocrystalline perovskite and spinel magnetic mixed oxides materials have gained immense importance due to their novel properties, which are significantly different from those of their bulk counterparts [1]. Nanocrystals of spinel ferrites, with general formula MFe2O4 (where M = Ni, Cu and Zn) are most interesting class of magnetic materials due to its facinating properties such as low melting point, high spectfic heat, large expansion coefficent and low magnetic transition temperature[2,3]. Because of these properties, ferrite materials are widely used in ferrofluid technology, information storage and magnetic pigments[4-6]. Especially, due to their peculiar magnetic properties and ability to respond at the molecular level, magnetic nanostructures are potential candidates for biomedicine such as targeted drug delivery [7], diagnostics [8], and magnetic separation [9]. These materials are also being explored as contrast agents in magnetic resonance image (MRI) [10], thermo responsive drug carriers [11] as well as in the thermal activation therapy of cancer [12]. The crystal structure of spinel ferrite compounds have a cubic close packing of O2- ions structure linked with two sub-lattice sites namely tetrahedral (A-sites) and octahedral (B-sites) [13]. The magnetic and other properties of spinel ferrite can be varied systematically by changing the identity of the ion, their charges and their distribution among the tetrahedral and octahedral sites [14]. Zinc ferrite (ZnFe2O4) and cobalt ferrite (CoFe2O4) have been most extensively studied system, because they exhibit the typically normal and inverse spinel ferrite respectively [15]. Nickel ferrite (NiFe2O4) is a well known inverse spinel structure ferrite with Ni2+ ions at octahed...
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... low temperature surfactant Tween80-assisted hydrothermal method to produce nanocrystaline nickel ferrite (NiFe2O4) and copper nickel ferrite (Cu1-xNixFe2O4, 0≤x≤0.5) using fine metal powders as raw materials. The formation of single spinel phase requires high calcination temperature. Therefore, in the present work, hydrothermal process was adopted because metal hydroxides were devoped after the hydrothermal reaction which were calcined at high temperature i.e.850oC to produce the desired spinel ferrite oxides.The thermal stability, phase development, microstructures, sintering characteristics and the distribution of cations in tetrahedral and octahedral sites of developed nanosized crystal structure ferrite materails were examined by TG-DTA, FTIR, XRD and SEM and Mössbauer spectroscopy. The impedance properties of sintered ferrite materials were also ascertained.
HYPOTHESIS: My hypothesis is that none of the Crayola colors are pure colors because they are a mixture of other color components.
Beryllium is a highly toxic metal and if exposed to it, at or above the threshold values, it can lead to a chronic beryllium disease (CBD) (i.e. berylliosis) or an acute beryllium disease. Toxic exposure to beryllium is most often thru an inhalation pathway. Beryllium has a variety of effects. Some beryllium combines with a protein and is deposited in the liver, spleen and kidneys, but the beryllium when bound with a biological protein, a hapten, can result in the chronic form of the disease which is believed to be a delayed hypersensitivity immune response. The major toxicological effects of beryllium are on the respiratory tract,specifically the lungs and their alveoli.
There are many types of distortions occurring in the ideal perovskite structure due to the flexibility inherent inside the perovskite structure. Resulting the tilting of the octahedra. Then displacement of cations takes place from the centres of their respective coordination in polyhedral. The distortion of the octahedral is accelerated by electronic factors. Most the physical properties of perovskite structure depend on these distortions. Particularly the electronic, magnetic and dielectric properties which are so important for many of the applications of perovskite materials. These materials have different useful magnetic and electronic properties. Most of the properties depends upon some defects like vacancies, dislocations, stacking faults, grain boundaries et...
Nutrilite, a “complex for hair, nails and skin,” is the advertisement presented in the magazine, Optimal Health. This magazine sells many products, but it is especially known for its vitamins and other nutrients of top quality and brand. The magazine is meant for the people who are members and independent business owners of Amway products. In the magazine, the products are shown with colorful pictures same as those shown in the ad for Nutrilite. Doctor Sam Rehnborg, President of Nutrilite Health Institute stated, “In this 80th year of Nutrilite brand, we are proud to say that we are the number one selling brand of vitamins and dietary supplements in the world.” The ad for Nutrilite gives us a good visualization with a convincing presentation
STRUCTURE Kevlar Aramid Fiber is a synthetic (man-made) material known as Polymer. A polymer is a chain that is made up of many similar molecular groups, better known as ‘monomers’ that are bonded together. The ‘Monomers’ are made up of fourteen Carbon atoms, two Nitrogen atoms, two Oxygen atoms and ten Hydrogen atoms. A single Kevlar polymer chain could possibly have anywhere from one to five million monomers bonded together. A group of polymer chains can be organised together in a fiber.
excellent chemical stability and corrosion resistivity [].The magnetic and dielectric characteristics of hexagonal ferrites strongly depend
Denture teeth can be made of acrylic poly(methyl methacrylate) (PMMA) or composite resins. PMMA is a polymer - a material made the from joining of methyl methacrylate monomers. Properties of PMMA include resistance to abrasion, chemical stability and a high boiling point. (Jun Shen et al. 2011). However, weak flexure and impact strength of PMMA are of concern as they account for denture failure. (Bolayir G, Boztug A and Soygun K. 2013). Composite denture teeth are made of a three distinct phases - filler, matrix and coupling agents. Out of the types of composite teeth available, nano-filled composite teeth are preferred. Composite teeth have a PMMA coating around the tooth and a high content of filler particles. This gives them strength, higher resistance to forces than acrylic teeth and provides compete polymerization due to the PMMA coating. (Anusavice, K. J., Phillips, R. W., Shen, C., & Rawls, H. R, 2012). If the interface between the PMMA denture base and PMMA or composite teeth was weak, the denture will not be able to sustain occlusal forces, making the base-teeth interface, an entity of significance.
In order to separate the mixture of fluorene, o-toluic acid, and 1, 4-dibromobenzene, the previously learned techniques of extraction and crystallization are needed to perform the experiment. First, 10.0 mL of diethyl ether would be added to the mixture in a centrifuge tube (1) and shaken until the mixture completely dissolved (2). Diethyl ether is the best solvent for dissolving the mixture, because though it is a polar molecule, its ethyl groups make it a nonpolar solvent. The compounds, fluorene and 1, 4-dibromobenzene, are also nonpolar; therefore, it would be easier for it to be dissolved in this organic solvent.
Iron phosphate, or FePO4 in chemistry symbol, has a highly similar structure to that of quartz, which has a
The Synthesis of Alum from Aluminum lab centralized on the creation of potassium aluminum sulfate dodecahydrate from a set amount of aluminum, and using quantitative analysis to then compare the actual yield to the theoretical yield. The synthesis of alum was conducted through a series of steps involving aluminum foil, potassium hydroxide, and sulfuric acid. Given that aluminum is amphoteric, meaning it can dissolve in both strong acids and strong bases, potassium hydroxide and sulfuric acid were both suitable for the dissolution of aluminum. There are multiple applications to synthesizing alum; from eliminating waste in the environment by repurposing, to utilizing alum as a medical treatment, the practicality of alum is immense.
My investigation was to test to see what condition borax crystals would grow best in. The problem was, “Do borax crystals grow best at room temperature, in a fridge, or in an ice bath?” My hypothesis was that the crystals would grow the largest in the freezer. My idea was that the ice would cause the crystals to expand and weigh the most out of the three.
BACKGROUND Types of Silica Crystalline silica may be of several distinct types. Quartz, a form of silica and the most common mineral in the earth's crust, is associated with many types of rock. Other types of silica include cristobalite and tridymite. Potential for Exposure During Construction Concrete and masonry products contain silica, sand and rock containing silica. Since these products are primary materials for construction, construction workers may be easily exposed to respirable crystalline silica during activities such as the following: Chipping, hammering, and drilling of rock Crushing, loading, hauling, and dumping of rock   high dust concentrations.
The basis for the understanding of the heat treatment of steels is the Fe-C phase diagram. Because it is well explained in earlier volumes of Metals Handbook and in many elementary textbooks, the stable iron-graphite diagram and the metastable Fe-Fe3 C diagram. The stable condition usually takes a very long time to develop, especially in the low-temperature and low-carbon range, and therefore the metastable diagram is of more interest. The Fe-C diagram shows which phases are to be expected at equilibrium for different combinations of carbon concentration and temperature. We distinguish at the low-carbon and ferrite, which can at most dissolve 0.028 wt% C at 727 oC and austenite which can dissolve 2.11 wt% C at 1148 oC. At the carbon-rich side we find cementite. Of less interest, except for highly alloyed steels, is the d-ferrite existing at the highest temperatures. Between the single-phase fields are found regions with mixtures of two phases, such as ferrite + cementite, austenite + cementite, and ferrite + austenite. At the highest temperatures, the liquid phase field can be found and below this are the two phase fields liquid + austenite, liquid + cementite, and liquid + d-ferrite. In heat treating of steels the liquid phase is always avoided. Some important boundaries at single-phase fields have been given special names. These include: the carbon content at which the minimum austenite temperature is attained is called the eutectoid carbon content. The ferrite-cementite phase mixture of this composition formed during cooling has a characteristic appearance and is called pearlite and can be treated as a microstructural entity or microconstituent. It is an aggregate of alternating ferrite and cementite particles dispersed with a ferrite matrix after extended holding close to A1. The Fe-C diagram is of experimental origin. The knowledge of the thermodynamic principles and modern thermodynamic data now permits very accurate calculations of this diagram.
The perovskite materials are of considerable technological importance, particularly with regard to physical properties such as pyro and piezoelectricity , dielectric susceptibility, linear and nonlinear optic effects. Many of these properties are gross effects, varying enormously from one perovskite to another and differences in crystal structures are hardly apparent . Effects of the impending transition are evident in some of the crystal properties at temperatures at least a few degrees away from Tc . Substances BaTiO3 and SrTiO3 have very high values of the permittivity due to low frequency of soft mode . It may be inferred that at room temperature BaTiO3 exhibits number of advantages over the other ferroelectrics such as a high mechanical strength , resistance to heat (due to positive temperature coefficient restivity , PTCR ) and moisture , presence of ferroelectric properties with in a broad range of temperature (its Curie point is high ≈ 400 K ) and ease of manufacturing . The presence of an abnormally high permittivity in BaTiO3 is connected with the ‘looseness’ of the crystal lattice of this substance . ( The sum of the atomic radii of titanium and oxygen ions 1.96 is less than the distance between these ions in the lattice 1.99 . The compression of the structure when atom of Ba is replaced by that of Sr drastically reduces dielectric constant and the temperature of the Curie point ) .
Consequently, as the magnetic field passes through the medium, the particles that are right below the head gap tend to align in the same direction as this field. Once the individual magnetic dipoles of the particles are aligned, they no longer cancel out and a net magnetic field is observed in that region. Many magnetic particles are now operating together to produce a cumulative field with the same direction. Due to the hysteresis properties of ferromagnetic materials, the individual particles retain their magnetic dipoles as well as the net field.