Computer assisted education in health economics for medical advisers

A computer-based distance learning study aid on health economics (HELP) for medical advisers was developed from an existing paper course using a user-centred, prototyping approach. We illustrate and discuss this approach. The prototypes were iteratively tested and refined with potential users. The initial prototype was used for market research which included a survey of medical and pharmaceutical advisers. Results from the market research established the study aid's feasibility. The design of the study aid was guided by the market research and by application of an architectural analysis and design framework. HELP was designed in the form of an electronic, frame-based book with self-tests and navigational facilities that permit additional exploration. On-line journal articles were included for users' reference. The strategy adopted for delivery of the new course consists of presenting the computer study aid together with the paper course. The authoring shell that was developed is generically reusable for other courses with other teaching and learning strategies.     

Managed care: a call for strategic management in the dental office

Strategic management of any business will enable it to prosper in challenging times of change. Strategic planning is not characteristically found only in large corporations. Indeed, small business, such as solo private practices, can gain much from the process. The successful practice is one that is proactive rather than reactive; it has learned to become the beneficiary of change, rather than its victim.     

Glass-ceramic bonding in alumina/CBN abrasive systems

A glass-ceramic bond which can be applied in alumina/CBN abrasive systems was developed by the method of liquid-phase sintering of a homogenized mixture of alumina abrasives and bonding medium containing various amounts of B₂O₃. Microstructural and mechanical examinations have shown that the amount of B₂O₃ present in the starting glass frit determines the ultimate properties of the glass-ceramic bond which can be successfully used in the Al₂O₂/CBN abrasive systems.     

Definition of the optimum freezing rate-1. Investigation of structure and ultrastructure of beef M. longissimus dorsi frozen at different freezing rates

The influence of freezing rate on location, shape and size of ice crystals formed during freezing of beef M. longissimus dorsi, as well as its influence on ultrastructure, were investigated. Muscle samples were frozen at different rates: 0·22 cm/h and 0·39 cm/h (cooling agent was chilled air), and 3·33 cm/h, 3.95 cm/h, 4·92 cm/h and 5·66 cm/h (cooling agent was liquid carbon dioxide which expanded in the sucking-pipe of the tunnel freezer).

It was found that by slow freezing (freezing rates 0·22 cm/h and 0·39 cm/h) 30·00 μm). An increase in the freezing rate was followed by a change in ice crystal location. In this case they had also been formed intracellularly. The number of crystals increased while their size decreased.

The most intensive fibre damage was found in samples frozen at a rate of 0·22 cm/h, and the least in samples frozen at a rate of 3·95 cm/h with a freezing temperature of −50°C.     

Collaborative Writing of Text and Hypertext

A good writer understands his audience. Collaborative writing allows authors to act as readers and thus to create text which an audience is more likely to appreciate. This paper describes four sets of experiences in collaborative writing. In one of the experiences secondary school students who were unable to produce a sophisticated document independently were able to produce a quality document through a group process. Given the correct combination of authors and goals, a simple computer editor can be very helpful. Hypertext differs from text in that links among chunks of text are made explicit. It could be argued that collaborative writing would work particularly well with hypertext because the links among the writers' ideas could be more easily explored. In experiences with graduate students at two universities, this hypothesis has not been supported. The students did not understand how these links should be created and thus could not collaboratively write hypertext.     

An adsorption-based mercury sensor with continuous readout

A novel readout procedure for a mercury sensor has been proposed. The sensor is based on the surface adsorption. Mercury vapor is adsorbed at the surface of a thin gold layer patterned into four meanders which are connected into a Wheatstone bridge configuration. Sensing is achieved by the resistivity change of the gold film during mercury adsorption. Direct output from the sensor is electric voltage. It takes an additional procedure to convert voltage to mercury concentration. This type of sensor is improved by introducing continuous readout procedure for the voltage–concentration conversion. By using this readout procedure it is possible to monitor mercury vapor concentration as a function of time. Readout is based on the Langmuir time–dependent adsorption theory. This paper illustrates a practical implementation of the new readout procedure.     

Evaluation of the composition and morphology of a WTi/Si system processed by a picosecond laser

In this work we studied the influence of laser radiation on the composition, structure and morphology of WTi thin films deposited on n-type (100) silicon wafers. The films were deposited by d.c. sputtering from a 70:30 at% W-Ti target, using Ar ions, to a thickness of ??190 nm. Irradiation was performed with a pulsed Nd:YAG laser operating at 1064 nm, whereas the pulse duration was 150 ps. Laser fluences of 3.2 and 5.9 J/cm² were found to be sufficient for modification of the WTi/silicon target system. The results show: (i) ablation of WTi thin film and a Si substrate in the central zone of spots, (ii) appearance of hydrodynamic features like resolidified material, (iii) partial ablation of the WTi thin film at the periphery and (iv) appearance of thin film cracks at the far periphery. On the non-ablated areas, the laser modification induced changes in composition, such as inter-mixing of components at the WTi/Si interface with formation of silicides in both metals. Surface oxidation was the dominant process in the ablated areas, which is demonstrated by the presence of a SiO₂ phase.     

Phase structure in segmented polyurethanes having fatty acid-based soft segments

Structural studies on two segmented polyurethanes prepared from modified oleic acid soft segments and butane diol/diphenylmethane diisocyanate hard segments, were performed. Polyurethanes were thermoplastic elastomers with 50% and 70% soft segment concentration (SSC) for TPU-50 and TPU-70, respectively. DMA revealed the co-continuous morphology in TPU-50 and dispersed hard domains in the soft matrix in TPU-70. AFM showed micron size globules in TPU-70 ascribed to hard segment-rich superstructures. Alternating small soft and hard domains were present in TPU-50, with ～15 nm lateral dimensions and local modulus deviations from 40 to 50 MPa, consistent with co-continuous morphology. The dispersed hard domains in the soft matrix of TPU-70, and co-continuous phases in TPU-50 morphology was confirmed. USAXS showed the domain spacing of TPU-50 was about 13.3 nm. TPU-70 demonstrated domain spacing of about 11.3 nm. USAXS revealed that the interface between phase-separated domains exhibited surface-fractal-like behavior.