Influence of Nd-Co Substitution on Structural,Electrical, and Dielectric Properties of X-Type Hexagonal Nanoferrites

A series of single phase X-type hexagonal ferrites with concentration Sr_2?x Nd _x Ni₂Fe_28?y Co _y O₄₆ (x = 0.02, 0.04, 0.06, 0.08, 0.10 and y = 0.1, 0.2, 0.3, 0.4, 0.5) has been prepared by sol-gel method sintered at 1250 °C for 6 h. The x-ray diffraction analysis reveals the single phase of X-type hexagonal ferrites. The particle size was calculated by using SEM and TEM. The ferrite substituted with Nd³⁺ and Co²⁺ has average particle size in the range of 40-50 nm. The room temperature electrical resistivity experiences the significant enhancement from a value of 1.1 × 10⁷ to 2.03 × 10⁸ Ωcm with the increase in Nd³⁺ and Co²⁺ concentration. The dielectric constant exhibits high value at low frequencies and decreases with the increase of frequency. The tangent dielectric loss shows the abnormal behavior which can be explained on the basis of hopping between the Fe²⁺ and Fe³⁺ ions on octahedral sites. The maximum value of tangent loss at low frequencies reflects the application of these materials in medium frequency devices (MF).     

Performance evaluation of a pure oxygen‐based activated sludge system treating a combined paint industry wastewater and domestic sewage

Activated sludge system based on pure oxygen has been developed to increase the biodegradation of wastewater. This system was used for the treatment of combined wastewater from the paint industry effluent and sewage. The results of continuous test showed that it is possible to achieve 87.8–93.6% COD, and 97.7–99.2% of BOD removal resulting in an effluent quality of 55–90mg/L of COD and less than 10.0mg/L of BOD. Dissolved oxygen content through out the tank showed a concentration, ranging between 3.26 and 3.9mg/L, indicating good oxygenation in the system. Excess sludge generated in the ASP was found to be 3.0kg/d and it has a good manurial value with NPK of 112, 68 and 32mg/L, respectively. Moreover the sludge showed very good settling character with a capillary suction time of 8.0 seconds.     

Nutrient removal potential of emergent ( Scirpus articulatus ) and floating ( Lemna major ) macrophytes

Nutrient removal capacity of Lemna major (floating macrophyte) was compared with Scirpus articulatus (emergent macrophyte) in hypertrophic mesocosms held in situ . While Lemna removed orthophosphate mainly from waterphase, Scirpus on the other hand, took up their phosphorus exclusively from the sediment. Plant recovery of both nitrogen and phosphorus was high in emergent macrophyte than in floating macrophyte. Introduction of macrophyte resulted in decline of denitrifying bacteria, but increase in heterotrophic bacterial populations. Counts of heterotrophic bacterial population were significantly higher in case of Lemna than in Scirpus . Decline of phytoplankton number was more pronounced in case of Lemna due to its shading effect compared to Scirpus . It'is concluded that reclamation ability of floating Lemna was short lived because of nutrient removal mainly from water phase whereas, the nutrient removal mechanism in emergent Scirpus was primarily through the root system from the sediment. Differential rates of nutrient storage was responsible for short term nutrient uptake by Lemna , whereas, it was reverse in case of Scirpus .     

MRT letter: Quantum noise removal and classification of breast mammogram images

Because of the limitations of the X‐ray hardware systems in mammogram machines, the quality of the breast mammogram images may undergo from poor resolution or low contrast. Quantum noise occurs in the mammogram images during acquisition due to low‐count X‐ray photons. In this work, an adaptive frost filter has been used to remove quantum noise. Local binary patterns have been extracted to classify breast mammograms into benign and malignant using different classifiers. Results show the superiority of the proposed algorithm in terms of sensitivity, specificity, and accuracy. Mammographic Institute Society Analysis database of mammography has been used for experimentation. Peak signal‐to‐noise ratio and structural similarity index measure are used to test the validity of adaptive frost filter. Experiment results show that proposed technique produces better results. Microsc. Res. Tech. 2012. © 2012 Wiley Periodicals, Inc.     

Microstructure,optical and dielectric properties of cobalt-doped zinc ferrite nanostructures

Journal of Materials Science: Materials in Electronics - In the present work, we have explored the physical properties of ZnFe2?xCoxO4 (0?≤?x?≤?0.06)...     

Influence of temperature on structural and magnetic properties of Co0·5Mn0·5Fe2O4 ferrites

Co_0·5Mn_0·5Fe₂O₄ ferrites have been synthesized using a single-step sol-gel auto-combustion method in which the metal nitrate (MN)-to-citric acid (CA) ratio was adjusted to 0.5: 1 and pH to 7, respectively. The structural and magnetic properties of as-burnt and annealed samples were studied as a function of temperature. The inverse spinel structure was confirmed by X-ray diffraction (XRD) and crystallite size was estimated by the most intense peak (311) using Scherrer’s formula. Contrary to earlier studies reported in the literature, both as-burnt and annealed samples exhibit crystalline behaviour. Room temperature magnetic properties were studied using vibrating sample magnetometer (VSM) with field strengths up to ±10 kOe. Lattice constant and crystallite size increased as the annealing temperature was increased. However, the coercivity (H _c) initially increased and then decreased with the increase of crystallite size. The variation in coercivity is ascribed to the transition from a multi-domain to a single-domain configuration.     

The effects of hydrogen on aluminum-induced crystallization of sputtered hydrogenated amorphous silicon

The effects of hydrogen on aluminum-induced crystallization (AIC) of sputtered hydrogenated amorphous silicon (a-Si:H) were investigated by controlling the hydrogen content of a-SiH films. Nonhydrogenated (a-Si) and hydrogenated (a-Si:H) samples were deposited by sputtering and plasma-enhanced chemical vapor deposition (PECVD). All aluminum films were deposited by sputtering. Hydrogen was introduced into the sputter-deposited a-Si films during the deposition. After deposition, the samples were annealed at temperatures from 200°C to 400°C for different periods of time. X-ray diffraction (XRD) patterns were used to confirm the presence and degree of crystallization in the a-Si:H films. For nonhydrogenated films, crystallization initiates at a temperature of 350°C. The crystallization of sputter-deposited a-Si:H initiates at 225°C when 14% hydrogen is present in the film. As the hydrogen content is decreased, the crystallization temperature increases. On the other hand, the crystallization initiation temperature for PECVD a-Si:H containing 11at.%H is 200°C. Further study revealed that the crystallization initiation temperature is a function, not only of the total atomic percent hydrogen in the film, but also a function of the way in which the hydrogen is bonded in the film. Models are developed for crystallization initiation temperature dependence on hydrogen concentration in a-Si:H thin films.     

Binary matrix for MALDI imaging mass spectrometry of phospholipids in both ion modes

Phospholipids (PLs) are the major building block molecules of cellular membranes. Their composition varies depending on cell types and cellular compartments. Thus, the information regarding PL distribution in tissue has important physiological and pathological significance. Recent developments in imaging mass spectrometry (IMS) have allowed complete mapping of the PL species on tissue. The IMS technique can detect different classes of PLs as well as their location information directly from tissue sections. PL head groups carry either positive and/or negative charges; therefore, IMS experiments must be conducted in both positive- and negative-ion mode to detect all types of phospholipids. Several conventional matrixes were applied on tissue for better identification. This study was conducted to enable appropriate matrix selection and optimized matrix preparation for IMS experiments in both ion modes that maximize PL identification from a single brain tissue section. The optimized matrix 2,5-dihydroxybenzoic acid (DHB) and α-cyano-4-hydroxycinnamic acid (CHCA) with a mixture of trifluoroacetic acid (TFA) and piperidine as ion pairing agents showed improved stability and consistency during both ion mode experiments and successfully identified >100 peaks of PLs determined by parent ion m/z value. Further tandem mass spectrometric analysis (MS/MS) was performed to those PLs that are anatomically important according to their distribution on rat brain tissue section.