Converse Magnetoelectric Experiments on a Room Temperature Spirally Ordered Hexaferrite

Experiments have been performed to measure magnetoelectric properties of room temperature spirally ordered Sr3Co2Fe24O41 hexaferrite slabs. The measured properties include the magnetic permeability, the magnetization and the strain all as a function of the electric field E and the magnetic intensity H. The material hexaferrite Sr3Co2Fe24O41 exhibits broken symmetries for both time reversal and parity. The product of the two symmetries remains unbroken. This is the central feature of these magnetoelectric materials. A simple physical model is proposed to explain the magnetoelectric effect in these materials.Comment: 6 pages, 5 figure

RISK AND RETURN TO IP GRAIN PRODUCTION: THE CASE OF HIGH OIL CORN

Returns for soybeans, commodity corn and high oil corn under an export and domestic market buyer's-call contract were simulated. High oil corn is competitive with commodity corn when yield drag is two percent and bundling reduces seed cost. Commodity loan rate is important in reducing high oil corn price risk.Crop Production/Industries,

Effect of pressure on the crystal structure of L-serine-I and the crystal structure of L-serine-II at 5.4 GPa

The crystal structure of L-serine has been determined at room temperature at pressures between 0.3 and 4.8 GPa. The structure of this phase ( hereafter termed L-serine-I), which consists of the molecules in their zwitterionic tautomer, is orthorhombic, space group P2(1)2(1)2(1). The least compressible cell dimension (c), corresponds to chains of head-to-tail NH ... carboxylate hydrogen bonds. The most compressible direction is along b, and the pressure-induced distortion in this direction takes the form of closing up voids in the middle of R-type hydrogen-bonded ring motifs. This occurs by a change in the geometry of hydrogen-bonded chains connecting the hydroxyl groups of the - CH2OH side chains. These hydrogen bonds are the longest conventional hydrogen bonds in the system at ambient pressure, having an O ... O separation of 2.918 (4) Angstrom and an O ... O ... O angle of 148.5 (2)degrees; at 4.8 GPa these parameters are 2.781 (11) and 158.5 (7) degrees. Elsewhere in the structure one NH ... O interaction reaches an N ... O separation of 2.691 (13) Angstrom at 4.8 GPa. This is amongst the shortest of this type of interaction to have been observed in an amino acid crystal structure. Above 4.8 GPa the structure undergoes a single-crystal-to-single-crystal phase transition to a hitherto uncharacterized polymorph, which we designate L-serine-II. The OH ... OH hydrogen-bonded chains of L-serine-I are replaced in L-serine-II by shorter OH ... carboxyl interactions, which have an O ... O separation of 2.62 (2) Angstrom. This phase transition occurs via a change from a gauche to an anti conformation of the OH group, and a change in the NCalphaCO torsion angle from -178.1 (2)degrees at 4.8 GPa to -156.3 (10)degrees at 5.4 GPa. Thus, the same topology appears in both crystal forms, which explains why it occurs from one single- crystal form to another. The transition to L-serine-II is also characterized by the closing-up of voids which occur in the centres of other R-type motifs elsewhere in the structure. There is a marked increase in CH ... O hydrogen bonding in both phases relative to L-serine-I at ambient pressure.</p

Non-Gaussian statistics of electrostatic fluctuations of hydration shells

We report the statistics of electric field fluctuations produced by SPC/E water inside a Kihara solute given as a hard-sphere core with a Lennard-Jones layer at its surface. The statistics of electric field fluctuations, obtained from numerical simulations, are studied as a function of the magnitude of a point dipole placed close to the solute-water interface. The free energy surface as a function of the electric field projected on the dipole direction shows a cross-over with the increasing dipole magnitude. While it is a single-well harmonic function at low dipole values, it becomes a double-well surface at intermediate dipole moment magnitudes, transforming to a single-well surface, with a non-zero minimum position, at still higher dipoles. A broad intermediate region where the interfacial waters fluctuate between the two minima is characterized by intense field fluctuations, with non-Gaussian statistics and the variance far exceeding the linear-response expectations. The excited state of the surface water is found to be lifted above the ground state by the energy required to break approximately two hydrogen bonds. This state is pulled down in energy by the external electric field of the solute dipole, making it readily accessible to thermal excitations. The excited state is a localized surface defect in the hydrogen-bond network creating a stress in the nearby network, but otherwise relatively localized in the region closest to the solute dipole

Sound propagation over uneven ground and irregular topography

The goal of this research is to develop theoretical, computational, and experimental techniques for predicting the effects of irregular topography on long range sound propagation in the atmosphere. Irregular topography here is understood to imply a ground surface that is not idealizable as being perfectly flat or that is not idealizable as having a constant specific acoustic impedance. The interest of this study focuses on circumstances where the propagation is similar to what might be expected for noise from low-attitude air vehicles flying over suburban or rural terrain, such that rays from the source arrive at angles close to grazing incidence. The activities and developments that have resulted during the period, August 1986 through February 1987, are discussed

The effect of pressure on the crystal structure of hexagonal L-cystine

The crystal structure of hexagonal L-cystine has been determined at room temperature at pressures between 0.4 and 3.7 GPa; unit-cell dimensions were measured up to 6.4 GPa. The structure of this phase consists of molecules in their zwitterionic form, and crystallizes in the hexagonal space group P6 122. The structure consists of hydrogen-bonded layers which are strongly reminiscent of those seen in a-glycine, and consist of R 44(16) hydrogen-bonded ring motifs. These layers are connected on one side by the disulflde bridges within the cystine molecules, and on the other by NH⋯O hydrogen bonds to other glycine-like layers. The most compressible unit-cell dimension, and the direction of greatest strain in the structure, is along the c-axis, and application of pressure pushes the layers closer together. The compression occurs approximately equally in the regions of the interlayer hydrogen bonds and the disulflde bridges; in the latter, changes in the C-S-S-C torsion angles allow the cystine molecules to act like springs. The effects of pressure can be interpreted in terms of closing-up of voids in the structure, and this leads to (i) a lessening of the N-C-C-O and C-S-S-C torsional angles, (ii) shortening of the N-H⋯O hydrogen bonds by 0.10-0.60 Å and (iii) a further shortening of an already short S⋯S contact from 3.444 (4) Å to 3.264 (4) Å. © 2005 International Union of Crystallography Printed in Great Britain - all rights reserved

Electronic Transport in the Oxygen Deficient Ferromagnetic Semiconducting TiO2−δ_{2-\delta}

TiO$_{2-\delta}$ films were deposited on (100) Lanthanum aluminates LaAlO$_{3}$ substrates at a very low oxygen chamber pressure $P\approx 0.3$ mtorr employing a pulsed laser ablation deposition technique. In previous work, it was established that the oxygen deficiency in these films induced ferromagnetism. In this work it is demonstrated that this same oxygen deficiency also gives rise to semiconductor titanium ion impurity donor energy levels. Transport resistivity measurements in thin films of TiO$_{2-\delta}$ are presented as a function of temperature and magnetic field. Magneto- and Hall- resistivity is explained in terms of electronic excitations from the titanium ion donor levels into the conduction band.Comment: RevTeX4, Four pages, Four Figures in ^.eps forma

Optimising Community-Based Forest Management Policy in Indonesia: a Critical Review

Community-based forest management (CBFM) is a popular concept in many countries, covering over 400 million hectares worldwide. In Indonesia, CBFM is viewed as an important component of the forestry sector with the government's goal to establish 5.6 million hectares of CBFM by 2011 (twice the area of industrial plantation forests). The Indonesian government is pursuing CBFM as a strategy to reduce deforestation of tropical forests, to alleviate poverty in rural communities, and to contribute timber supplies to the processing industry.There has been a belief that CBFM can lead to a physical and socio-economic transformation at the local level. However, in practice, especially in Indonesia, this claim appears problematic because in over 35 years since it has been officially introduced it does not appear to have contributed significantly to address the problems of deforestation and rural poverty.Despite the government's ambitious goal for CBFM, there are several challenges, for instance the entrenched poverty of many rural communities and inconsistent and unsupportive policies of CBFM at the national, provincial, and local government. This paper is intended to explore, discusses, and criticize the implementation of CBFM policies in various countries and in particular in Indonesia. This paper also aims to explore its challenges in the future development in Indonesia

Effect of allopurinol on phosphocreatine recovery and muscle function in older people with impaired physical function:a randomised controlled trial

Background: Allopurinol has vascular antioxidant effects and participates in purinergic signalling within muscle. We tested whether allopurinol could improve skeletal muscle energetics and physical function in older people with impaired physical performance. Methods: We conducted a randomised, double blind, parallel group, placebo-controlled trial, comparing 20 weeks of allopurinol 600 mg once daily versus placebo. We recruited community-dwelling participants aged 65 and over with baseline 6-min walk distance of &lt;400 m and no contraindications to magnetic resonance imaging scanning. Outcomes were measured at baseline and 20 weeks. The primary outcome was post-exercise phosphocreatine (PCr) recovery rate measured using 31P magnetic resonance spectroscopy of the calf. Secondary outcomes included 6-min walk distance, short physical performance battery (SPPB), lean body mass measured by bioimpedance, endothelial function and quality of life. Results: In total, 124 participants were randomised, mean age 80 (SD 6) years. A total of 59 (48%) were female, baseline 6-min walk distance was 293 m (SD 80 m) and baseline SPPB was 8.5 (SD 2.0). Allopurinol did not significantly improve PCr recovery rate (treatment effect 0.10 units [95% CI, −0.07 to 0.27], P = 0.25). No significant changes were seen in endothelial function, quality of life, lean body mass or SPPB. Allopurinol improved 6-min walk distance (treatment effect 25 m [95% 4–46, P = 0.02]). This was more pronounced in those with high baseline oxidative stress and urate. Conclusion: Allopurinol improved 6-min walk distance but not PCr recovery rate in older people with impaired physical function. Antioxidant strategies to improve muscle function for older people may need to be targeted at subgroups with high baseline oxidative stress. </p