Search results

Probleme des Plastizitätsthcorie (Problems of the Theory of Plasticity). By William Prager [Birkhäuser Verlag, Basel and Stuggart, Sf 12.50].

This study aims to present a numerical study of atomic structure for aluminium nitride (AlN) when the crystal was assumed grown on different orientation of sapphire substrate. The change of the AlN atomic structure with sapphire orientation was associated to the interface between the AlN and the sapphire. The results from this study would provide a guideline in selecting suitable orientation of sapphire for obtaining desirable AlN crystals, in particular, for reducing threading dislocation density in the AlN/sapphire templates for developing UV LEDs.

The approach of atomic structure by visualization for electronic and structural analysis numerical method to develop shape of atomic geometry to evaluate which plane are more suitable for the AlGaN technology UV-LED based.

The calculation based on ratio on first and second layers can be done by introduction of lattice constant.

With plane’s color of cutting plane on bulky materials, all the shape looks the same.

By implementing this method, the authors can save time to find the most suitable plane on the growth structure.

All authors of this research paper have directly participated in the planning, execution or analysis of the study; all authors of this paper have read and approved the final version submitted; the contents of this manuscript have not been copyrighted or published previously; the contents of this manuscript are not now under consideration for publication elsewhere; the contents of this manuscript will not be copyrighted, submitted or published elsewhere, whereas acceptance by the journal is under consideration.

Describes a non‐contact optical sensing technology called C3D that is based on speckle texture projection photogrammetry. C3D has been applied to capturing all‐round 3D models of the human body of high dimensional accuracy and photorealistic appearance. The essential strengths and limitation of the C3D approach are presented and the basic principles of this stereo‐imaging approach are outlined, from image capture and basic 3D model construction to multi‐view capture and all‐round 3D model integration. A number of law enforcement, medical and commercial applications are described briefly including prisoner 3D face models, maxillofacial and orofacial cleft assessment, breast imaging and foot scanning. Ongoing research in real‐time capture and processing, and model construction from naturally illuminated image sources is also outlined.

HELICOPTER primary gearbox systems are arguably one of the most demanding forms of gear system. The requirements for high torque transmission, light weight and reliability combine to form the most demanding specifications for gear manufacturers.

MUCH thought about the automatic control of machine tools has been confused by an imperfect understanding of what can be done, and of what the advantages of the various systems arc. Why is it desirable to use automatic control? The answer to this question depends on the production quantities involved. Where really large scale production is possible automatic control, combined with automatic transfer equipment, reduces the need for repetitive handling and machine control operations to be done by men, can greatly speed up production, and reduce the need for skilled and unskilled labour. This is not the type of work for which man is best suited, and he may be liable to make mistakes because of fatigue or boredom. In this type of automatic production line the operation can best be controlled mechanically by systems incorporating trips, limit switches, interlocks and the like, specially designed for the sequence of operations concerned. Such mechanical systems have been developed over the years, and many plants, such as those used by large steel works for the production of repetition forgings, show considerable ingenuity in their design. However, such plants are not applicable to a wide range of component designs made in comparatively small numbers, the normal state of affairs in the aircraft industry. Greater flexibility is obtained by the use of electronic control, and the computer which then has to be brought into the system can also carry out some of the more laborious drawing office processes, such as interpolation between ordinates.

This book is an extension of the author's previous book Dynamique générate des Vibrations published in Paris in 1943, where Professor Rocard presented the general principles of his dynamic theory, namely, that instability occurs by complete convergence of two natural frequencies and that the addition of resistances, whether positive or negative, always favours instability. The purpose of the present work is to expound the application of his theory.

THIS year's exhibition was held in the Horticultural Halls on March 25–28. As always there was much to interest the air‐craft engineer. It is only to be regretted that more space or more time, or both, cannot be found, so that visitors might be able to spend more time studying the exhibits, and less jostling with one another.

The 3D Systems stereolithography file format is a good workhorse for the rapid prototyping (RP) industry. It is supported by all major computer‐aided design (CAD) and RP manufacturers and there now exists a selection of third‐party software which supports this de facto standard and helps to make it work better. However, input to RP systems is sometimes best suited to the format of sliced contours. These may be produced from a three‐dimensional CAD model or via reverse engineering techniques such as laser scans and co‐ordinate measuring machines. Other sources include computed tomography and magnetic resonance imaging scans. Takes a brief look at both of the above methods, listing their advantages and disadvantages. Identifies several ways in which sliced data can be used to drive RP processes. Finally, presents in detail a methodology used to develop a direct and adaptive slicer from a commercial CAD system.

The purpose of this paper is to provide a comparative review of intensity‐modulated fiber optic sensors with non‐optical sensors for health monitoring applications, from the current research activities in the area.

A range of published research work in sensor design for four different health monitoring applications, including, lumbar spine bending, upper and lower limb motion tracking, respiration and heart rate monitoring, are presented and discussed in terms of their respective advantages and limitations.

This paper provides information on the various types of sensors applied into the health monitoring area. The sensing techniques of the fiber optic sensor for the stated applications are focused and compared in details to highlight their contributions.

A comparative review of published work is illustrated in an informative table content, to allow a clear idea of the current sensing approaches for health monitoring applications.

The fully automated 90 Inertia Welder made by the Caterpillar Tractor Co. is now available in Europe. In the inertia welding process, the parts to be welded are placed directly opposite one another. One of the parts, for example a valve stem, is held in a spindle collet. A flywheel of predetermined size and weight is attached to the spindle. The other part, the valve head, is automatically clamped in a rigid stationary chuck. The entire spindle assembly including the valve stem and flywheel is then accelerated. At a predetermined speed, the rotating part is disconnected from its drive source. Instantly, the rotating part is forced against its counterpart under precisely controlled pressure. As the flywheel assembly slows down, due to friction, the stored kinetic energy in the flywheel is discharged into the interface, resulting in the required heat and pressure to bring both parts to a desired plastic state. The result is said to be a superior molecular bond, grain refinement of the weld zone and a finished product with the full strength of the parent metal. With the addition of automatic loading and unloading, the cycle time of the Caterpillar 90 Inertia Welder has been reduced to about 8 to 9 sec, enabling it to perform in assembly line fashion under demands of high production, simply, quickly and economically.