Which vessel is more important in the supercharged flap--artery, vein, or both? An experimental study

The supercharged flap is one which is expected to attain better survival, by anastomosing the distal vessels of the flap to the recipient vessels. An experimental study is reported to determine whether the vessel to be anastomosed should be an artery, a vein, or both. The authors advise anastomosing an artery and a vein, but they believe that arterial inflow is more important than venous drainage.     

Measurement of the thermal diffusivity of thin films on substrate by the photoacoustic method

Measurements of the thermal diffusivity of thin films on substrate have been performed by the photoacoustic method. In order to examine the method we have built a new apparatus and proposed (1) a system calibration procedure using optically and thermally thick reference samples and (2) a data analysis procedure based on the RG (Rosencwaig and Gersho) theory. As a result of using a transparent photoacoustic cell, the systematic errors which are caused by stray light have been reduced. With this apparatus, measurements have been performed on platinum, titanium, and stainless steel (SUS304) thin foils (thickness form 50 to 100 µm) with three different liquid backing materials (water, glycerol, and ethyl alcohol). The reproducibility was within ±7% regardless of film thickness and substrate materials.     

Mean molal activity coefficients of aqueous scandium chloride, nitrate, bromide and perchlorate solutions at 25.0°

The mean molal activity coefficients of aqueous scandium chloride, nitrate, bromide and perchlorate solutions were determined at 25.0° for dilute to saturated concentrations, together with the activities of water. In the dilute solutions of scandium halides, the activity coefficients were obtained from electromotive force measurements on galvanic cells, and the osmotic coefficients of all four solutions above 0.1 mol kg⁻¹ were determined from the isopiestic measurements. Least-squares equations were fitted to these coefficients, which were then used to calculate the mean molal activity coefficients and water activities. The relationships between these results and the corresponding activity data for other rare earth salts, and to the cation hydration and ionic interactions, are discussed. The results on scandium perchlorate solutions suggested that the inner-sphere hydration number of tervalent scandium ion may be seven.     

A novel technique for a DC brushless motor without position sensors

A dc brushless motor is a kind of synchronous motor driven by an inverter and requires sensors to detect the rotor position. As one of the methods, the induced voltages of a brushless motor have been utilized in practice. However, there are some problems in this method, e.g., the motor can obtain insufficient torque due to the low induced voltages in a low-speed range. This paper proposes a new method which controls the inverter angular frequency ω₁ by using inherent characteristics wherein the torque current i_r is almost proportional to the internal phase angle φ where the primary flux of a synchronous motor is controlled to be constant. If the parameters of a motor are given exactly, the speed regulation is quite small and the transient characteristics with high response and high starting torque are obtained. Furthermore, it is possible to operate a synchronous motor in the field-weakening range. Here, the principle of the control method and the performance characteristics of a dc brushless motor having no position sensors are discussed. The simulation and the experimental results of the tested machine show that the proposed method is very useful for practical applications.     

Day-night variations of behavioral and autonomic thermoregulatory responses to lipopolysaccharide in rats

This study investigated the day-night differences in behavioral and autonomic thermoregulatory responses to bacterial lipopolysaccharide (LPS) in rats. Male rats were housed individually in cages with a 12: 12 h light dark cycle at an ambient temperature of 24 degrees C. The rats were placed in a box with a temperature gradient and intraperitoneally injected with LPS (10 micrograms/kg). The preferred ambient temperature (Tpr) was estimated by the location of the rats in the box, and intraperitoneal temperature (Tb) was measured by a biotelemetry system. Measurements were taken during the light and dark phases of the day. LPS produced fever in both phases. The magnitude of rise in Tb did not differ between the two periods. In the dark phase, Tpr significantly increased during the development of fever and decreased during the defervescence, while it did not change throughout the febrile course during the light phase. In a separate experiment, rats were loosely restrained and placed in a direct calorimeter. Their colonic temperature (Tcol), evaporative and nonevaporative heat loss and heat production were measured before and after intraperitoneal injections of LPS (10 micrograms/kg). Measurements were taken during the light and dark phases of the day. LPS induced fever in both phases. The magnitude of change in T col, heat loss, and heat production due to LPS did not differ between the two periods. These results suggest that the fertile response of rats to intraperitoneal LPS is not affected by the time of day. However, it seems that during LPS-induced fever, thermoregulatory behavior is not fully activated during the light phase of the day.     

Path tracking control of Lagrange systems with obstacle avoidance

This paper addresses a path tracking problem with obstacle avoidance for Lagrange systems. The proposed method is based on field potential methods in combination with navigation functions for obstacle avoidance. First, it is shown that a simple combination of the navigation function with the conventional path tracking controller does not work. Therefore, in order to cope with this problem, a new feedback law is proposed for a path parameter which characterizes the reference path. It is proved that the proposed controller achieves both path following and collision avoidance. Moreover, since the method adopts bounded navigation functions, the proposed controllers generate bounded input signals even when target systems approach obstacles. Finally, an experimental evaluation is performed with a two-link manipulator to illustrate the effectiveness of the proposed method.     

Drawing plane graphs nicely

Summary This paper presents two efficient algorithms for drawing plane graphs nicely. Both draw all edges of a graph as straight line segments without crossing lines. The first draws a plane graph convex if possible, that is, in a way that every inner face and the complement of the outer face are convex polygons. The second, using the first, produces a pleasing drawing of a given plane graph that satisfies the following property as far as possible: the complements of 3-connected components, together with inner faces and the complement of the outer face, are convex polygons. The running time and storage space of both algorithms are linear in the number of vertices of the graph.     

Making exhaustive search programs deterministic

This paper presents a technique for compiling a Horn-clause program intended for exhaustive search into a GHC (Guarded Horn Clauses) program. The technique can be viewed also as a transformation technique for Prolog programs which compiles away the ‘bagof’ primitive and non-determinate bindings. The class of programs to which our technique is applicable is shown with a static checking algorithm; it is nontrivial and could be extended. An experiment on a compiler-based Prolog system showed that our technique improved the efficiency of exhaustive search by 6 times for a permutation generator program. This compilation technique is important also in that it exploits the AND-parallelism of GHC for parallel search.     

Real-time simulation of lightweight rigid bodies

Unlike common rigid bodies, lightweight rigid bodies have special and spectacular motions that are known as free fall, such as fluttering (oscillation from side to side) and tumbling (rotation and sideways drifting). However, computer graphics applications cannot simulate the dynamics of lightweight rigid bodies in various environments realistically and efficiently. In this study, we first analyze the physical characteristics of free-fall motions in quiescent flow and propose a new procedural motion-synthesis method for modeling free-fall motions in interactive environments. Six primitive motions of lightweight rigid bodies are defined in a phase diagram and analyzed separately using a trajectory-search tree and precomputed trajectory database. The global paths of free-fall motions are synthesized on the basis of these primitive motions by using a free-fall motion graph whose edges are connected in the Markov-chain model. Then, our approach integrates external forces (e.g., a wind field) by using an improved noise-based algorithm under different force magnitudes and object release heights. This approach exhibits not only realistic simulation results in various environments but also fast computation to meet real-time requirements.