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In 2001/2002 a study was undertaken to establish whether significant differences existed between the levels of development of several entrepreneurial attributes, as perceived by undergraduate business students from three universities in three different countries. The rationale was that, if entrepreneurial attributes could be identified as more developed in one country than in another, solutions could be provided for developing these attributes in others. The primary objective of this study is to investigate and compare the levels of development of entrepreneurial attributes of undergraduate business students in the present study (2010) to the levels of development reported by undergraduate business students in the 2001/2002 study. Cronbach alpha coefficients were calculated to assess the reliability of the measuring instrument and ttests to establish significant differences. Cohen’s d statistics were calculated to establish practical significance. The findings suggest that the educational environment and entrepreneurship education policy of the Dutch university participating in this study could provide solutions as to how entrepreneurial attributes among students could be developed further.

Previous studies suggest that there is a significant variation in both shape and physical properties from filament to filament in a multifilament superconducting Bi-2223/Ag tape. We are investigating this variation for a tape with a high critical current density (J/sub c/). For this study, we extracted all the filaments from a specially prepared high-quality tape having J/sub c/ (0 T, 77 K) = 45 kA/cm/sup 2/ with 19 disconnected filaments. By attaching current leads and voltage taps to the filaments, we are able to measure electrical properties on a scale of 200-300 /spl mu/m. The experiments show a large variation in filament properties. The conductivity of a filament at room temperature is proportional to its critical current density J/sub c/ at 77 K (self-field) and filaments with a higher transition temperature T/sub c/ do also show a higher J/sub c/. There is also a variation in the magnetic field behavior of the filaments. SEM pictures of the filaments also show large variations. The filaments from the center of the tape, which are thinner and have a larger aspect ratio (and thus a larger silver-filament interface), show better grain alignment and fewer impurities than filaments from the edges.

Bi2Sr2Ca2Cu3Ox/Ag tape superconductors are used in applications like power cables and transformers. In these applications the superconductor is exposed to an alternating magnetic field that has different orientations with respect to the tape surface. In this paper the angle dependency of the magnetisation loss is considered from two points of view. First the measurement technique with pickup coils is analysed theoretically. Measured magnetisation loss in uni-directional magnetic field with various orientations and rotating magnetic field are compared. When the orientation is changed from perpendicular (0°) to parallel (90°) applied magnetic fields, the contribution of the perpendicular field component to the magnetisation loss is dominant up to 60°. A new model to describe the angle dependency of the magnetisation loss, based on the measured loss in perpendicular and parallel magnetic field is developed. Deviations between models and the measured loss are explained with the help of the theoretical analysis of the measurement technique. The new model is not only applicable for the magnetisation loss but also for other AC loss components.

A model to describe the angular dependence of the critical current of a superconducting Bi-2223/Ag tape is developed. The model is based on a Gaussian distribution of the misalignment angles of the grains. With this model it is possible to calculate the standard deviation of the misalignment angle of the grains from critical current measurements in a magnetic field oriented perpendicular and parallel to the tape plane. This enables us to determine the critical current behaviour for all orientations of the magnetic field. The theory is confirmed in an experimental way. The angular dependence of the critical current of the measured tape can be described at 77 K in the region between 0 and 200 mT within 3% by using a standard deviation of 7.8° in the misalignment angle.

BSCCO/Ag tape superconductors are used in applications like power cables, transformers and motors/generators. In these applications, the superconductor is exposed to an alternating magnetic field that can have different orientations with respect to the tape. In applications like three-phase power cables and motors/generators, the tape is exposed to a rotating magnetic field. This paper describes a measurement setup to determine the magnetisation loss of short pieces (10 cm) of tape superconductor in uni-directional magnetic field with arbitrary direction and rotating magnetic field. Measurements are performed in liquid nitrogen using the pick-up coil technique. The sensitivity of the setup is sufficient to measure the magnetisation loss accurate down to magnetic field amplitudes of 0.5 mT, also in magnetic field applied parallel to the wide face of the conductor. A relation is verified that described the measured magnetisation loss in a rotating magnetic field with the results obtained for a uni-directional field. The magnetisation loss in a rotating magnetic field can be described, in most cases, with the component of the magnetic field perpendicular to the wide face of the tape conductor. Only when the parallel magnetic field component becomes more than two times larger than the perpendicular component that its contribution to the loss becomes significant.

The aim of this study was to assess the after-effects of night work on mental performance. Twenty experienced shift workers were examined in a baseline condition and during recovery after a night shift period. For control purposes eight other workers were studied in a similar baseline condition and during recovery after a non-night shift period. The subjects performed memory search tasks before and after a bicycle ergometer test. Cycling had different effects on mental performance, leaving the speed and accuracy of the reactions unchanged in the baseline and the non-night-recovery condition, while decreasing the mental performance in the night-recovery condition. Also in this condition a higher level mental effort investment was measured. These results suggest an incomplete recovery on the first fully undisturbed day-off (32 h) after a period of night work, manifesting itself in a deterioration of the efficiency of the information processing.

Previously, Bayesian methods have been proposed for neural networks to solve regression and classification problems. These methods claim to overcome some difficulties encountered in the standard approach such as overfitting. However, an implementation of the full Bayesian approach to neural networks as suggested in the literature applied to classification problems is not easy. In fact we are not aware of applications of the full approach to real world classification problems. In this paper we discuss how the Bayesian framework can improve the predictive performance of neural networks. We demonstrate the effects of this approach by an implementation of the full Bayesian framework applied to two real world classification problems. We also discuss the idea of calibration to measure the predictive performance.

Transversal and longitudinal homogeneity of Bi-2223/Ag tapes made by a tape-in-rectangular tube process with high filament aspect ratio was studied. Spatially resolved transport measurements (“magnetic knife”), Hall probe measurements and local V–I measurements were used to obtain the Ic distribution across and/or along the tape sample. The Ic distribution in the width of the filaments shows a minimum in the filaments centre and a maximum is measured near the filament edges. A periodical variation of longitudinal Ic values is observed by local V–I and by Hall probe measurements. Transversal and longitudinal filaments cross-sections were obtained and compared to transport critical currents.

A comparison has been made of the infrared spectra of alumina with molybdenum oxide-alumina in both the oxidized and reduced forms. In the case of molybdena-alumina prepared via adsorption of gaseous MoO2(OH)2, the spectra show that a practically complete monolayer of Mo6+ oxide covers the alumina. After reduction with hydrogen the hydroxyls of the carrier appear. From the reversibility of reduction and oxidation under mild conditions it has been established that the reduced oxide is present as an interrupted monolayer.