Strain induced anomalous red shift in mesoscopic iron oxide prepared by a novel technique

Nano magnetic oxides are promising candidates for high density magnetic storage and other applications. Nonspherical mesoscopic iron oxide particles are also candidate materials for studying the shape, size and strain induced modifications of various physical properties viz. optical, magnetic and structural. Spherical and nonspherical iron oxides having an aspect ratio, ~2, are synthesized by employing starch and ethylene glycol and starch and water, respectively by a novel technique. Their optical, structural, thermal and magnetic properties are evaluated. A red shift of 0⋅24 eV is observed in the case of nonspherical particles when compared to spherical ones. The red shift is attributed to strain induced changes in internal pressure inside the elongated iron oxide particles. Pressure induced effects are due to the increased overlap of wave functions. Magnetic measurements reveal that particles are superparamagnetic. The marked increase in coercivity in the case of elongated particles is a clear evidence for shape induced anisotropy. The decreased specific saturation magnetization of the samples is explained on the basis of weight percentage of starch, a nonmagnetic component and is verified by TGA and FTIR studies. This technique can be modified for tailoring the aspect ratio and these particles are promising candidates for drug delivery and contrast enhancement agents in magnetic resonance imaging

A Novel Slotless Halbach-Array Permanent-Magnet Brushless DC Motor for Spacecraft Applications

This paper presents the design and analysis of a novel machine family—the enclosed-rotor Halbach-array permanentmagnet brushless dcmotors for spacecraft applications. The initial design, selection of major parameters, and air-gap magnetic flux density are estimated using the analytical model of the machine. The proportion of the Halbach array in the machine is optimized using finite element analysis to obtain a near-trapezoidal flux pattern. The machine is found to provide uniform air-gap flux density along the radius, thus avoiding circulating currents in stator conductors and thereby reducing torque ripple. Furthermore, the design is validated with experimental results on a fabricated machine and is found to suit the design requirements of critical spacecraft applications

Optimal Design of a Surface Mounted Permanent-Magnet BLDC Motor for Spacecraft Applications

This paper presents the optimal design of a surface mounted permanent-magnet (PM) Brushless direct-current (BLDC) motor meant for spacecraft applications. The spacecraft applications requires the choice of a motor with high torque density, minimum cogging torque, better positional stability and high torque to inertia ratio. Performance of two types of machine configurations viz Slotted PMBLDC and Slotless PMBLDC with Halbach array are compared with the help of analytical and finite element (FE) methods. It is found that unlike a Slotted PMBLDC motor, the Slotless type with Halbach array develops zero cogging torque without reduction in the developed torque. Moreover, the machine being coreless provides high torque to inertia ratio and zero magnetic stiction

Characterization of Bacteriocins from Bacillus licheniformis strain BTHT8 and Bacillus subtilis strain BTFK101 isolated from marine sediment

Pathogenic microorganisms such as Bacillus cereus, Listeria Monocytogenes and Staphylococcus sp have caused serious diseases, and consequently contributed to considerable economic loss in the food and agricultural industries. Antibiotics have been practically used to treat these pathogens since penicillin G was discovered more than half a century ago. Many different types of antibiotics have been discovered or synthesized to control pathogenic microorganisms. Repetitive use and misuse of antibiotics by the agricultural and pharmaceutical industries have caused the emergence of multidrug-resistant microorganisms, even to the strongest antibiotics currently available; therefore, the rapid development of more effective antimicrobial compounds is required to keep pace with demand. Bacteria were isolated from marine water and sediment samples collected from various locations off the coast of Cochin and salt pans of Tuticorin using pour plate technique. One hundred and twelve isolates were obtained. Seventeen isolates exhibiting antimicrobial activity were segregated after primary screening. The secondary screening which was aimed at selection of bacteria that produce proteinaceous inhibitory compounds, helped to select five strains viz. BTFK101, BTHT8, BTKM4, BTEK16 and BTSB22. The five isolates inhibited the growth of six Gram positive test organisms viz. B. cereus, B. circulans, B. coagulans, B. pumilus, Staphylococcus aureus and Clostridium perfringens. After quantitative estimation of the bacteriocin production, the two strains BTFK101 and BTHT8 were selected for further study.

Del yo al euro : una propuesta didáctica de cooperación transnacional : educación permanente de adultos. 'From the I to the euro : a didactic proposal for transnational cooperation : permanent adult education'.

La obra se presenta en edición bilingue español/inglés .- Incluye una sección de apéndices en la que aparecen tablas y gráficos que recogen datos estadísticos sobre la experiencia didáctica, así como información general sobre la UE

A Systems Approach to the Torque Control of a Permanent Magnet Brushless Motor

Many approaches to force control have assumed the ability to command torques accurately. Concurrently, much research has been devoted to developing accurate torque actuation schemes. Often, torque sensors have been utilized to close a feedback loop around output torque. In this paper, the torque control of a brushless motor is investigated through: the design, construction, and utilization of a joint torque sensor for feedback control; and the development and implementation of techniques for phase current based feedforeward torque control. It is concluded that simply closing a torque loop is no longer necessarily the best alternative since reasonably accurate current based torque control is achievable.

Temporary and Permanent Buyout Prices in Online Auctions

Increasingly used in online auctions, buyout prices allow bidders to instantly purchase the item listed. We distinguish two types: a temporary buyout option disappears if a bid above the reserve price is made; a permanent one remains throughout the auction or until it is exercised. In a model featuring time-sensitive bidders with uniform valuations and Poisson arrivals but endogenous bidding times, we focus on finding temporary and permanent buyout prices maximizing the seller's discounted revenue, and examine the relative benefit of using each type of option in various environments. We characterize equilibrium bidder strategies in both cases and then solve the problem of maximizing seller's utility by simulation. Our numerical experiments suggest that buyout options may significantly increase a seller’s revenue. Additionally, while a temporary buyout option promotes early bidding, a permanent option gives an incentive to the bidders to bid late, thus leading to concentrated bids near the end of the auction.

Vint-i-cinc anys de docència, cinc lleis d'educació i una permanent sensació d'incertesa : una reflexió sobre l'educació amb la LOE com a teló de fons. 'Veinticinco años de docencia, cinco leyes de educación y una permanente sensación de incertidumbre : una reflexión sobre la educación con la LOE como telón de fondo'.

Describe la incertidumbre en que el trabajo de los docentes se ve inmerso, debido a los continuos cambios de gobierno, los cuales afectan al quehacer educativo a través de la creación de leyes. En medio del debate permanente los docentes se sienten huérfanos, solos, ante unas necesidades en las aulas que son difíciles de dar respuesta debido a la falta de formación, de habilidades y sobretodo de apoyo externo, de la sociedad y de la família.

Un model de formaci?? permanent de l'entrenador de futbol

Resumen tomado del autor

Percepci?? dels entrenadors espanyols de tennis d'alta competici?? sobre la seva formaci?? permanent : situaci?? actual i perspectives de futur

Resumen tomado del autor. Contiene tablas varias: de resultado, encuesta y gu??a de entrevista

Inspecció educativa i formació permanent del professorat. 'Inspección educativa y formación permanente del profesorado'.

Resumen tomado del autor

La formació a distància en el programa de formació permanent del professorat a les Illes Balears. 'La formación a distancia en el programa de formación permanente del profesorado en las Islas Baleares'.

Resumen tomado del autor

Programa de formació de formadors : cap a la professionalització dels assessors de formació permanent del professorat no universitari de les Illes Balears. 'Programa de formación de formadores : hacia la profesionalización de los asesores de formación permanente del profesorado no universitario de las Islas Baleares'.

Resumen tomado del autor

L'educació emocional en la formació permanent del professorat. 'La educación emocional en la formación permanente del profesorado'.

Resumen tomado de la revista

Ser mestre a l'escola petita : reflexions sobre la formaci?? inicial i permanent dels mestres. 'Ser maestro en la escuela peque??a : reflexiones sobre la formaci??n inicial y permanente de los maestros'

Se estudia la delicada situaci??n de las escuelas rurales y la gran importancia de la actuaci??n de los docentes que trabajan en ellas. Se analiza el perfil que tendr??a que tener el profesional que trabaja en estos centros y para ello se indica c??mo deber??an ser la formaci??n inicial y permanente espec??ficas del maestro rural, temas olvidados en los actuales planes de estudio de magisterio.