A Terrain Rendering Method Using Vertical Ray Coherence

Ray casting may be applied to the terrain rendering from DTMs (digital terrain models). In this paper we propose a ray casting method which exploits exact vertical ray coherence. This method not only achieves a good performance, but also allows any set of viewing parameters. To analyse the vertical ray coherence property, we define the following terms: a ray plane which is perpendicular to the sea-level plane and passes through the COP (centre of projection), and the corresponding ray line which is the line of intersection of the ray plane and the projection plane. Vertical ray coherence can be stated as: if two rays pass through the same ray line, they pass over the identical set of points on the DTM base plane. After a ray is cast on the DTM, we can get a good starting point to cast another ray using this property. Our method tries to cover the projection plane with ray lines. Since ray lines are not parallel to each other, it is a difficult task to cover the entire plane. In fact all ray lines intersect at a point (COP′). We first generate a set of ray lines sufficient to cover the projection plane near COP′. As pixels get further from COP′, more ray lines are generated to fill most of the gaps between pixels covered by the previous set of ray lines. Rays passing through the same ray line are effectively cast using vertical ray coherence. To fill remaining pixels not covered by ray lines, pixel values of vertical/horizontal neighbours are interpolated. To cast rays efficiently, successive points generated by a line algorithm are followed along the projection of the rays on the DTM base plane. © 1997 by John Wiley & Sons, Ltd.     

A Compact Differential Formula for the First Derivative of a Unit Quaternion Curve

This paper presents a compact differential formula for the first derivative of a unit quaternion curve defined on SO(3) or S³. The formula provides a convenient way to compute the angular velocity of a rotating 3D solid. We demonstrate the effectiveness of this formula by deriving the differential properties of various unit quaternion curves^1–5 at the curve end points.     

Mechanical and electrical properties of In-Bi solder at Bi2212 superconductor interface with annealed Ag spray layers and Ag precoating layers

The electrical properties of solder contact layers between Cu-Ni shunt metal and tube type Bi₂₂₁₂ superconductor that is applied in superconducting fault current limiter were studied. The contact properties of the solders are improved not only by Ag precoating layers, but also by the pre-sprayed Ag layer and subsequent Ag precoating layers. The annealed Ag sprayed layers onto Bi₂₂₁₂ superconductor prior to Ag electroplating work as protecting layers for the superconductor from plating solutions. The contact angle of the electroplated Ag layer is 42.91° and decreases to 15.25° and 5.88° with Ag sprayed layer and additional Ag electroplated layers. The Ag sprayed layer with suitable annealing prior to Ag electroplating improves contact strength of the Ag electroplated layer by about 12% due to denser microstructure of the Ag electroplated layers.     

Operator Based Two Loop Nonlinear Forced Vibration Control of a Flexible Plate

A nonlinear forced vibration control method for a flexible plate with piezoelectric actuators is proposed in this paper. A model of a flexible plate, taking into account the hysteresis of the piezoelectric actuator, is given. In addition, the design of nonlinear control system is given by using the operator theory. Finally, the effectiveness of the proposed nonlinear control system is confirmed by simulation and experimental results.     

Development and Experimental Evaluation of Strip Shape Prediction Model for Sendzimir Rolling Mills

It is difficult to obtain the desired strip shape using Sendzimir rolling mills because small diameter work rolls can be easily deformed by the rolling force. To control the strip shape effectively, it is important to understand the relationship between the behavior of the shape actuator and the variation of the strip shape. A numerical model based on the contact element method was proposed for the prediction of strip shape. In this numerical model, the relationships between the actuating forces, the roll deflections, the thickness profiles of the entry and exit sides, and the strip shape were considered. The proposed numerical model for strip shape prediction was evaluated by computer simulation and experiment with respect to various AS-U roll and first intermediate roll positions.     

ENZYMIC LIPID PEROXIDATION IN BEEF MUSCLE MICROSOMES AS AFFECTED BY ELECTRICAL STIMULATION AND POSTMORTEM MUSCLE EXCISION TIME

Left sides of 10 beef carcasses were electrically stimulated at I h postmortem; right sides were not stimulated. Longissimus dorsi (LD) and trapezius (TP) muscles were removed from stimulated and nonstimulated sides after 1.5 and 24 h of chilling (0–2°C). Microsomal lipid peroxidizing activity (the amount of malonalde-hyde produced per mg of microsomal protein) was not affected by electrical stimulation, was higher for muscles removed after 24 h chilling than for those removed after 1.5 h chilling, and was higher for TP than for LD muscles. Differences observed in lipid peroxidizing activity could not be explained readily by microsomal fatty acid compositions.     

Limonoid Glucosides in Commercial Citrus Juices

Commercial citrus juices were found to contain very high concentrations of limonoid glucosides. TLC analyses showed the presence of these compounds averaging 320, 190 and 82 ppm in orange, grapefruit and lemon juices, respectively. The major glucoside in citrus juices was limonin 17-O-β-D-glucopyianoside, which constituted over 50% of the total limonoid glucosides in the juices.