Distributed-Controlled Multiagent Mobile Platform with Digital Actuation Concept for Space Applications

This paper describes an architecture for a multiagent robotic system that consists of a number of identical units. The homogeneous units are mechanically connected to construct a mobile platform named a “multiagent transportation (MAT) system.” Every unit has its local controller that communicates only with its adjacent units. This basic configuration of supervisorless structure affirmatively confines the dependence of each unit to a local area, and therefore any unit can be removed from or added into any part of a MAT system regardless of the timing and without disturbing the performance of the whole system. This flexibility of configuration significantly contributes to easy maintenance of units, such as battery charging or hot-replacing for faulty units. Utilizing this flexibility, MAT systems are able to adapt to a variety of tasks including transportation application and to target objects of various shapes and range of mass. These characteristics of MAT systems are the strong advantages for mobile robots, especially for ones activated in distant places, e.g., robotic planetary explorers. A proposed example unit of a MAT system shown in this paper employs a parallel link manipulator as its leg, and the digital-actuation (D-actuation) concept is applied for the local unit controller to actuate the leg. Together with the basic design of the example units, the controlling framework is described with simulation results to show the feasibility of the whole mobile system architecture.     

Pulsed power production of ozone in O2/N2 ina coaxial reactor without dielectric layer

Very short duration pulsed streamer discharges have been used to produce ozone in a gas mixture of nitrogen and oxygen at atmospheric pressure. The ratio of nitrogen to oxygen in the mixture was varied in the range from 2.5/0.5 to 0.5/2.5, while maintaining a total flow rate of 3 l/min. The production of ozone was found to be higher for a specific mixture ratio of N₂/O₂ than that in oxygen or in dry air. The production of ozone in O₂ was higher than that in dry air. The production yield of ozone (g/kWh) increased with decreasing nitrogen in the O₂/N₂ mixture. It has been found that the peak of the streamer discharge current decreased with time after application of the pulsed power. This decrease in the current corresponded with the increase in the ozone production and is attributed to the loss of electrons in the discharge current due to their attachment to ozone to form negative ions     

Optical frequency domain ranging by a frequency-shifted feedbacklaser

This paper describes the theoretical and experimental study of a new technique for optical frequency domain ranging (OFDR) by a frequency-shifted feedback (FSF) laser. In conventional OFDR, a frequency chirped single-mode laser is used as a light source to convert a distance into a beat frequency, and a tradeoff exists between measurement range and resolution. The FSF laser output consists of periodically generated chirped frequency components whose chirp rate is faster than 100 PHz/s (P=10¹⁵), By use of the FSF laser, the tradeoff is removed and long-distance high-resolution OFDR is realized In the experiment, a distance of 18.5 km was measured with a resolution of 20 mm     

Characteristics of driver and receiver circuits with a passivetransmission line in RSFQ circuits

We report simulated results of-rapid single flux quantum (SFQ) circuits having driver, receiver, and passive transmission lines for propagating SFQ pulses to investigate the design criteria. We have studied the equivalent input/output resistance of the driver/receiver in various bias conditions and found that the resistance is almost proportional to the bias current of the driver/receiver. Furthermore, we have proposed inserting a series resistor at the end of the superconducting passive transmission line (PTL) for avoiding undesirable flux trapping in the loop and for isolation in regard to the DC current. We also found that the reduction of the bias margin due to the resistance is rather small when the resistance is much smaller than the impedance of the PTL. An operating margin of more than 30% was obtained in the driver/receiver circuits including the PTL and the series resistor     

Relationships between left ventricular mass, left ventricular work and coronary artery size in aortic regurgitation--possible mechanism of myocardial ischemia

To investigate the relationships between coronary artery size, left ventricular (LV) mass, and LV stroke work in aortic regurgitation (AR), these values were measured in 19 patients with severe AR. Twenty normal subjects and 15 patients with mitral regurgitation (MR) were used as control groups. The coronary area index, i.e., the coronary cross-sectional area divided by body surface area (BSA), was larger in the AR group than in the control groups in all measured sites except for the peripheral left anterior descending coronary artery (LAD) and right coronary artery (RCA). However, the coronary area index divided by the LV mass was significantly smaller in AR and MR patients than in normal subjects. Furthermore, the coronary area index divided by LV stroke work was smaller in AR patients than in MR patients and normal subjects. These results suggest that the coronary blood flow associated with the increased LV mass and stroke work caused by regurgitation was insufficient in patients with severe AR, especially in the area of the LAD. Therefore, the occurrence of myocardial ischemia in patients with severe AR may involve inadequate enlargement of the coronary artery which perfuses the LV, in addition to factors such as decreased coronary perfusion pressure, increased coronary artery resistance and decreased coronary flow reserve.     

Discrepancy between provocative test and clinical results following endovascular obliteration of spinal arteriovenous malformation

The isolated and perfused kidney of the spontaneously hypertensive rat (SHR) exhibits an increased vascular reactivity to serotonin when compared to normotensive Wistar-Kyoto (WKY) rats. Experiments were designed to determine the involvement of a prostanoid constricting factor in the augmented response to serotonin in the SHR kidney. Kidneys taken from male (12 months) SHR and WKY rats were studied in parallel and perfused with Tyrode's solution at constant, optimal flow rates. Vasoconstrictor response were recorded as increases in perfusion pressure. The dose-response curves to serotonin obtained in the SHR were shifted to the left compared to the WKY. Indomethacin decreased the responses to the smaller doses of serotonin in the SHR, but increased those to the higher doses of the monoamine in the WKY. The responsiveness to the monoamine was no longer significantly different in the two strains in the presence of the inhibitor of cyclooxygenase. Dazoxiben, an inhibitor of thromboxane synthetase, did not alter the responses to serotonin in either the WKY and SHR kidneys. These experiments suggest that a prostanoid, but not thromboxane A2, may play a role in the augmented response to serotonin in the kidney of aged SHR.     

HEAT TRANSFER IN A CONDUCTIVE-HEATING AGITATED DRYER

The heat transfers between the heating plane and the granular materials in both the “Stationary heating-plane type” and the “Moving heating-plane type” of the conductive-heating agitated dryers were discussed mainly from the view point of the scale-up of the dryer. Under the condition of complete mixing in the bed of bulk materials, the heat transfer models proposed for both the two types of dryers can predict the heat transfer coefficients in any sizes of the dryers. However, the complete mixing is not usually accomplished in the large scale of dryer. Hence, an “Incomplete mixing model” was proposed to estimate the effect of the incompleteness of mixing on the heat transfer coefficient. In this model, the incompleteness of mixing can be apparently taken into consideration only by increasing the contact time.     

Clinical efficacy of imipenem/cilastatin sodium for respiratory infections in patients with lung cancer

Imipenem/cilastatin sodium (IPM/CS) was administered to 102 patients with respiratory tract infections and lung cancer. Patients with other serious diseases were excluded and a total of 73 patients were enrolled. They were divided into 12 patients who underwent surgery (operated group) and 61 who did not (non-operated group); the latter group included 28 patients treated with anticancer agents or radiation therapy (treated group) and 33 untreated patients (untreated group). IPM/CS was effective in 75% of the patients, both with and without surgery. The drug was effective in 81% of the treated group, although many of the patients had Stage III or more advanced cancer, as well as bronchial occlusion. IPM/CS was also effective in 69% of the untreated group, although many of the patients have serious infections and a PS (Performance Status) of 3 or greater. Thus, IPM/CS treatment achieved good results. Bacteriological studies showed that 3 out of 4 strains in the operated group and 16 out of 18 in the non-operated group were eliminated. Safety was evaluated in all patients. Two patients (2%) experienced side effects and two others (2%) showed abnormal clinical findings, but the symptoms were mild and resolved after discontinuation or completion of therapy. In conclusion, IPM/CS was very effective for treating respiratory infections in patients with lung cancer.     

Fruiting-inducing activity and antifungal properties of lipid components in members of Annelida

Fruiting-inducing activity and antifungal properties of lipid components in the phylum Annelida were examined. Some amphoteric cerebrosides carrying a phosphocholine group showed fruiting-inducing activity on Schizophyllum commune, and one of them possessed activity comparable to that of Sch II, the most potent substance known. Furthermore, alkyl lysophosphatidylcholines were found to have an inhibitory effect on the growth of phytopathogenic fungi, Alternaria kikuchiana and Phomopsis mali. The relationship between structure and biological activities is discussed.