Discovery learning approach to classic electrical machines principles

This paper aims at presenting the concept of Socratic interactions and discovery learning of classic electrical machines principles. The theories of electrical machines are by nature quite boring and abstract although there are a lot of experiments supported the theories. Traditional, students learnt the subject by drill and practice approach with standard textbooks. In the past two decades, computer is no doubt recognized to be the educational tool. The so-called “interactive” approach is applied to the learning process. Most of this approach applied to various subjects in different levels is mainly based on drill and practice. However, few packages are developed for electrical machine subject. In this paper, two different approaches “Rote Learning” and “Discovery Learning” applied to the interactive computer aided learning package of classic electric machine principles are discussed. Design of a discovery learning approach will also be presented

RFID Technology Enhancing Supply Chain Competence and E-Business: An Opportunity or a Threat?

Radio Frequency Identification (RFID), which uses radio waves to identify objects, was discovered in 1930s for military purposes and it transformed into commercial uses in 1980s in the United States. In this paper, we explore the research domains in RFID technology, innovation and diffusion theory, and supply chain management within the existing literature for exploring whether RFID enhances supply chain competence and ebusiness. This paper also forms a preliminary study base for researchers who may wish to carry on future research in this area

Magnetic ordering of Mn sublattice, dense Kondo lattice behavior of Ce in (RPd3)8Mn (R = La, Ce)

We have synthesized two new interstitial compounds (RPd3)8Mn (R = La and Ce). The Mn ions present in "dilute" concentration of just 3 molar percent form a sublattice with an unusually large Mn-Mn near neighbor distance of ~ 85 nm. While the existence of (RPd3)8M (where M is a p-block element) is already documented in the literature, the present work reports for the first time the formation of this phase with M being a 3d element. In (LaPd3)8Mn, the Mn sub-lattice orders antiferromagnetically as inferred from the peaks in low-field magnetization at 48 K and 23 K. The latter peak progressively shifts towards lower temperatures in increasing magnetic field and disappears below 1.8 K in a field of ~ 8 kOe. On the other hand in (CePd3)8Mn the Mn sublattice undergoes a ferromagnetic transition around 35 K. The Ce ions form a dense Kondo-lattice and are in a paramagnetic state at least down to 1.5 K. A strongly correlated electronic ground state arising from Kondo effect is inferred from the large extrapolated value of C/T = 275 mJ/Ce-mol K^2 at T = 0 K. In contrast, the interstitial alloys RPd3Mnx (x = 0.03 and 0.06), also synthesized for the first time, have a spin glass ground state due to the random distribution of the Mn ions over the available "1b" sites in the parent RPd3 crystal lattice.Comment: 18 figures and 20 pages of text documen

E-Book Technology in Libraries: An Overview

The shift towards electronically mediated texts entails major structural issues for libraries and the publishers and aggregators who supply them. Stakeholders within the digital supply chain are struggling to re-conceptualise the book as artefact (Esposito 2003). Academic and scholarly libraries are at the forefront of these changes and many are preparing for a significant shift from physical to electronic material presentation within the next few year. Within this context, we review some recent developments in the technology underpinning e-books, evaluate a number of e-business publishing models and introduce some of the key players

Onset voltage shift due to non-zero Landau ground state level in coherent magnetotransport

Coherent electron transport in double-barrier heterostructures with parallel electric and magnetic fields is analyzed theoretically and with the aid of a quantum simulator accounting for 3-dimensional transport effects. The onset-voltage shift induced by the magnetic field in resonant tunneling diodes, which was previously attributed to the cyclotron frequency $w_c$ inside the well is found to arise from an upward shift of the non-zero ground (lowest) Landau state energy in the entire quantum region where coherent transport takes place. The spatial dependence of the cyclotron frequency is accounted for and verified to have a negligible impact on resonant tunneling for the device and magnetic field strength considered. A correction term for the onset-voltage shift arising from the magnetic field dependence of the chemical potential is also derived. The Landau ground state with its nonvanishing finite harmonic oscillator energy $\hbar w_c /2$ is verified however to be the principal contributor to the onset voltage shift at low temperatures.Comment: 13 pages, and 3 figures. Accepted for publication in Phys. Rev.

Temperature correction to the Casimir force in cryogenic range and anomalous skin effect

Temperature correction to the Casimir force is considered for real metals at low temperatures. With the temperature decrease the mean free path for electrons becomes larger than the field penetration depth. In this condition description of metals with the impedance of anomalous skin effect is shown to be more appropriate than with the permittivity. The effect is crucial for the temperature correction. It is demonstrated that in the zero frequency limit the reflection coefficients should coincide with those of ideal metal if we demand the entropy to be zero at T=0. All the other prescriptions discussed in the literature for the $n=0$ term in the Lifshitz formula give negative entropy. It is shown that the temperature correction in the region of anomalous skin effect is not suppressed as it happens in the plasma model. This correction will be important in the future cryogenic measurements of the Casimir force.Comment: 12 pages, 2 figures, to be published in Phys. Rev.

Wealth and risk implications of the Dodd-Frank Act on the U.S. financial intermediaries

We contribute to the current regulatory debate by examining the wealth and risk effects of the Dodd- Frank Act on U.S. financial institutions. We measure the effects of key legislative events of the Act by means of a multivariate regression model using the seemingly unrelated regression (SUR) framework. Our results indicate a mixed reaction by financial institutions during the various stages of the Act’s legislative process. Further tests reveal that any positive reactions are driven by small and/or low risk institutions, while negative ones are consistent across subsets; except for investment banks. We also find market risk increases for most financial institutions that are dominated by small and/or low risk firms. The cross-section results reveal that large institutions fare better than their smaller counterparts and that large investment banks gain value at the expense of others. Overall, the Dodd-Frank Act may have redistributed value among financial institutions, while not necessarily reducing the industry’s riskiness

Fluctuations of the Retarded Van der Waals Force

The retarded Van der Waals force between a polarizable particle and a perfectly conducting plate is re-examined. The expression for this force given by Casimir and Polder represents a mean force, but there are large fluctuations around this mean value on short time scales which are of the same order of magnitude as the mean force itself. However, these fluctuations occur on time scales which are typically of the order of the light travel time between the atom and the plate. As a consequence, they will not be observed in an experiment which measures the force averaged over a much longer time. In the large time limit, the magnitude of the mean squared velocity of a test particle due to this fluctuating Van der Waals force approaches a constant, and is similar to a Brownian motion of a test particle in an thermal bath with an effective temperature. However the fluctuations are not isotropic in this case, and the shift in the mean square velocity components can even be negative. We interpret this negative shift to correspond to a reduction in the velocity spread of a wavepacket. The force fluctuations discussed in this paper are special case of the more general problem of stress tensor fluctuations. These are of interest in a variety of areas fo physics, including gravity theory. Thus the effects of Van der Waals force fluctuations serve as a useful model for better understanding quantum effects in gravity theory.Comment: 14 pages, no figure