Alberta Research Council

An effort is made to find the solution to the new challenges of modification advancements in ferrite technologies. The hypothetical variation in the structural, magnetic, and electrical properties of cubic spinel magnesium aluminum ferrites introduced by the substitution of doping elements has been rationalized and proven. The outcome of aluminum substitution on the magnesium ferrites has been examined and investigated. Spinel ferrites having compositions of MgAlxFe2-xO4 (x = 0.1, 0.2, 0.3, 0.4) were prepared by the sol-gel auto-combustion method. The prepared sample’s characterization, such as scanning electron microscopy (SEM), DC electrical resistivity, AC electrical resistivity, and dielectric properties measurements, were tested using the respective instruments. The grain size and crystal size of all samples were measured from the micrographs of SEM and XRD Data. It is found that the average grain size is within the range of 300 nm - 550 nm for all different series that are formed, keeping the samples at 1100 °C sintering temperatures. A two-probe method experiment with a temperature range of 30 °C to 500 °C gives data on DC electrical resistivity. The Curie temperature depends on the sintering temperature, and it increases with increasing doping concentration. Also, doping influences grain size, which decreases with increasing concentration. Analyzing the SEM micrographs, it is found that the average grain size must decrease in tendency with increasing Al content. DC electrical resistivity exhibits excellent semiconducting behavior. Frequency dependence, dielectric constant, and dielectric loss factors were measured, keeping the frequency range of 75 Hz to 130 MHz at room temperature. The result shows that the dielectric constant (e) and dielectric loss tangent (tan™) decrease with the increase in frequency, while the AC resistivity and Q-factor increase. Comparing the electrical properties of four compositions, it can be suggested that the mixed ferrite, sample-4 (x = 0.3), shows the highest Q-factor of all at 1100 °C.

Gallian's survey shows that there is a big variety of labelings of graphs. By means of (di)graphs products we can establish strong relations among some of them. Moreover, due to the freedom of one of the factors, we can also obtain enumerative results that provide lower bounds on the number of nonisomorphic labelings of a particular type. In this paper, we will focus in three of the (di)graphs products that have been used in these duties: the ⊗h-product of digraphs, the weak tensor product of graphs and the weak ⊗h-product of graphs.

Semi-automatic and power operated vertical flow pulse thresher-cum-winnower was developed by the author 1 for efficient threshing and winnowing of matured crops of a variety of pulses having diverse physical characteristics, wherein threshing and winnowing operations were carried out separately. Therefore it was upgraded to a compact, hybrid and fully automatic pulse thresher-cum-winnower by the author 1 to overcome power constraints in villages as well as to obtain combined operations of threshing, crushing and winnowing together. Feeding of dry crop into thresher is manual, while rest of operations are automatic without human touch. Significant features are >99% threshing and winnowing efficiency, almost nil seed loss and seed breakage, crushing all crop residues into powdery animal fodder, dust free cleaning of seeds, and by 3 hp prime mover; either oil engine with simplest clutch arrangement and/or with single phase electric motor. Threshing and crushing actions are executed by multiple progressive shears and impacts through a set of radial rotary beater and stationary beater inside a vertical hopper, like in semi-automatic pulse thresher. The crops flow vertically downwards into shear zones by scissoring actions of the beaters and gravity. Seeds are separated and cleaned by an improved winnower-cum-grader, and the crushed crop residues are disposed from the machine by a combined mechanism of walker and flat air jet. Configuration and performance of this fully automated vertical flow thresher for threshing of different types of pulses are presented and discussed.

The objective of the current paper is to extend the theoretical approach and an analytical solution, which was proposed by Babchin and Faybishenko (2014), for the evaluation of a capillary pressure (Pc) curve in porous media based on the apparent specific surface area, using an explicit combination of the relative permeability functions for the wetting and nonwetting phases. Specifically, in the current paper, the authors extended this approach by the application of two types of capillary bundle models with different formulations of effective capillary radius formulae. The application of the new models allowed the authors to improve the results of calculations of the effective average contact angle given in the paper by Babchin and Faybishenko (2014). The validation of the new models for calculations of the Pc curve is also given in this paper using the results of a specifically designed core experiment, which was originally conducted by Ayub and Bentsen (2001).

Accurate quantification of evaporative losses to the atmosphere from surface water bodies is essential for calibration and validation of hydrological models, particularly in remote arid and semi-arid regions, where intermittent rivers are generally minimally gauged. Analyses of the stable hydrogen and oxygen isotope composition of water can be used to estimate evaporative losses from individual pools in such regions in the absence of instrumental data but calculations can be complex, especially in highly variable systems. In this study, we reviewed and combined the most recent equations required for estimation of evaporative losses based on the revised Craig-Gordon model. The updated procedure is presented step-by-step, increasing ease of replication of all calculations. The main constraints and sources of uncertainties in the model were also evaluated. Based on this procedure we have designed a new software, Hydrocalculator, that allows quick and robust estimation of evaporative losses based on isotopic composition of water. The software was validated against measures of field pan evaporation under arid conditions in northwest Australia as well as published data from other regions. We found that the major factor contributing to the overall uncertainty in evaporative loss calculations using this method is uncertainty in estimation of the isotope composition of ambient air moisture. (C) 2015 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY license.