Bio-Processes of the Oxidation Ditch When Subjected to a Sub-Arctic Climate

Alaska's far northern area is sparsely populated primarily because of a severe climate which varies from northern temperate to Arctic. Construction and power costs are high. Skilled operating personnel are scarce and expensive, if available. Receiving streams are said to be delicate, particularily in the winter, when little possibility for reaeration exists due to a total ice cover. The oxidation ditch modification of the extended aeration activated sludge process appears to be well suited for the treatment of wastes in this environment. Past operating data on a plant of this type located in Interior Alaska (near Fairbanks) indicated it may be well suited to treat small volumes of domestic waste economically, with low sludge production, and minimal sensitivity to low temperatures.The work reported on herein was done under Contract No. RFP DACA 897l- R-0006 from the U. S. Army Cold Regions Research and Engineering Laboratory, Hanover, New Hampshire

Lattice expansion and non-collinear to collinear ferrimagnetic order in MnCr2_2O4_4 nanoparticle

We report magnetic behaviour of MnCr$_2$O$_4$, which belongs to a special class of spinel, known as chromite. Bulk MnCr$_2$O$_4$ shows a sequence of magnetic states, which follows paramagnetic (PM) to collinear ferrimagnetic (FM) state below T$_C$ $\sim$ 45 K and collinear FM state to non-collinear FM state below T$_S$ $\sim$ 18 K. The non-collinear spin structure has been modified on decreasing the particle size, and magnetic transition at T$_S$ decreases in nanoparticle samples. However, ferrimagnetic order is still dominating in nanoparticles, except the observation of superparamagnetic like blocking and decrease of spontaneous magnetization for nanoparticle. This may, according to the core-shell model of ferrimagnetic nanoparticle, be the surface disorder effect of nanoparticle. The system also show the increase of T$_C$ in nanoparticle samples, which is not consistent with the core-shell model. The analysis of the M(T) data, applying spin wave theory, has shown an unusual Bloch exponent value 3.35 for bulk MnCr$_2$O$_4$, which decreases and approaches to 1.5, a typical value for any standard ferromagnet, with decreasing the particle size. MnCr$_2$O$_4$ has shown a few more unusual behaviour. For example, lattice expansion in nanoparticle samples. The present work demonstrates the correlation between a systematic increase of lattice parameter and the gradual decrease of B site non-collinear spin structure in the light of magnetism of MnCr$_2$O$_4$ nanoparticles

Oscillating magnetoresistance due to fragile spin structure in metallic GdPd3_3

Studies on the phenomenon of magnetoresistance (MR) have produced intriguing and application-oriented outcomes for decades--colossal MR, giant MR and recently discovered extremely large MR of millions of percents in semimetals can be taken as examples. We report here the investigation of oscillating MR in a cubic intermetallic compound GdPd$_3$, which is the only compound that exhibits MR oscillations between positive and negative values. Our study shows that a very strong correlation between magnetic, electrical and magnetotransport properties is present in this compound. The magnetic structure in GdPd$_3$ is highly fragile since applied magnetic fields of moderate strength significantly alter the spin arrangement within the system--a behavior that manifests itself in the oscillating MR. Intriguing magnetotransport characteristics of GdPd$_3$ are appealing for field-sensitive device applications, especially if the MR oscillation could materialize at higher temperature by manipulating the magnetic interaction through perturbations caused by chemical substitutions.Comment: 10 pages, 7 figures. A slightly modified version is published in Scientific Report

Spin dynamics and frequency dependence of magnetic damping study in soft ferromagnetic FeTaC film with a stripe domain structure

Perpendicular magnetic anisotropy (PMA) and low magnetic damping are the key factors for the free layer magnetization switching by spin transfer torque technique in magnetic tunnel junction devices. The magnetization precessional dynamics in soft ferromagnetic FeTaC thin film with a stripe domain structure was explored in broad band frequency range by employing micro-strip ferromagnetic resonance technique. The polar angular variation of resonance field and linewidth at different frequencies have been analyzed numerically using Landau-Lifshitz-Gilbert equation by taking into account the total free energy density of the film. The numerically estimated parameters Land\'{e} $g$-factor, PMA constant, and effective magnetization are found to be 2.1, 2$\times10^{5}$ erg/cm$^{3}$ and 7145 Oe, respectively. The frequency dependence of Gilbert damping parameter ($\alpha$) is evaluated by considering both intrinsic and extrinsic effects into the total linewidth analysis. The value of $\alpha$ is found to be 0.006 at 10 GHz and it increases with decreasing precessional frequency.Comment: 5 Pages, 6 Figures, Regular Submissio

Antimicrobial activity of various extracts of whole plant of Anisomeles malabarica (Linn.) R. Br.

Anisomeles malabarica (Linn.) R.Br. is a traditional medicinal plant of Lamiaceae family, distributed throughout India. All the three extracts petroleum ether, Ethyl Acetate, methanol of Anisomeles malabarica (Linn.) R.Br. were tested for Antimicrobial efficacy against gram positive and gram negative bacterial and then fungal organisms. The methanolic extract of Anisomeles malabarica (Linn.) R.Br. were exhibited maximum antibacterial and anti fungal activity when compared with other two extracts. Hence it can be concluded that the methanolic extract of Anisomeles malabarica (Linn.) R.Br. possess a significant Antimicrobial activity. This also stands as a scientific support for the usage of this plant for wound healing