Limited Space (limited + space)

Distribution by Scientific Domains


Selected Abstracts


Proposal and development of radial air-gap coreless generator suitable for small wind turbine used in urban area

ELECTRICAL ENGINEERING IN JAPAN, Issue 1 2009
Toshiyuki Takahashi
Abstract Independent distributed power generation using small wind turbines is becoming more widespread as wind power generation increases. Installation of small wind turbines in densely populated urban areas is not only useful from the viewpoint of extracting wind power sources in weak-wind areas but also for making renewable energy easier to access when power supplies are closer to consumers. It is from this point of view that the authors proposed "urban wind power generation" using a collective system with a number of small vertical wind turbines, and have developed a suitable generator for low-speed vertical wind turbines such as a Savonius windmill. Based on a standard coreless generator, the proposed generator is designed to make the direction of the magnetic flux radial in order to install the magnets and coils on the outer end of the generator. The change of magnet composition and flux direction maximizes the speed of the flux change and output voltage within a limited space. With the above configuration, the power of the proposed generator is independent of the diameter. In this report, the authors describe and evaluate the fundamental performance of a prototype of the proposed generator. Based on the experiments, a maximum output power of 283 W was obtained. The obtained starting torque is small enough to begin rotation under weak wind conditions of no more than 1 m/s. Therefore, it is clear that the proposed "radial" coreless generator is suitable for self-starting and producing high power at low wind speed. © 2009 Wiley Periodicals, Inc. Electr Eng Jpn, 167(1): 26, 34, 2009; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/eej.20695 [source]


Applications of the Liquid Cyclone in Biological Separations

ENGINEERING IN LIFE SCIENCES (ELECTRONIC), Issue 2 2004
E. Ortega-Rivas
Abstract Hydrocyclone technology has been suggested as a practical alternative in solid/liquid separations involving biological materials. This paper reviews applications of hydrocyclones in food processing, considering the non-Newtonian nature of most suspensions treated in the food industry. The hydrocyclone is easy to install and operate, and requires very limited space. It represents an unsophisticated piece of equipment, which runs in a continuous manner and it can be operated at lower costs than most solid/liquid separation techniques. Hydrocyclones have been used in the food industry for the refining of starch, to separate gossypol from cottonseed protein in cottonseed oil processing, and for some other applications, such as multi-stage mixer/separator extraction systems for soluble coffee. More recently, some other applications in biological systems, which will be discussed in this article, have also been tested. [source]


Magnebike: A magnetic wheeled robot with high mobility for inspecting complex-shaped structures

JOURNAL OF FIELD ROBOTICS (FORMERLY JOURNAL OF ROBOTIC SYSTEMS), Issue 5 2009
Fabien Tāche
This paper describes the Magnebike robot, a compact robot with two magnetic wheels in a motorbike arrangement, which is intended for inspecting the inner casing of ferromagnetic pipes with complex-shaped structures. The locomotion concept is based on an adapted magnetic wheel unit integrating two lateral lever arms. These arms allow for slight lifting off the wheel in order to locally decrease the magnetic attraction force when passing concave edges, as well as laterally stabilizing the wheel unit. The robot has the main advantage of being compact (180 × 130 × 220 mm) and mechanically simple: it features only five active degrees of freedom (two driven wheels each equipped with an active lifter stabilizer and one steering unit). The paper presents in detail design and implementation issues that are specific to magnetic wheeled robots. Low-level control functionalities are addressed because they are necessary to control the active system. The paper also focuses on characterizing and analyzing the implemented robot. The high mobility is shown through experimental results: the robot not only can climb vertical walls and follow circumferential paths inside pipe structures but it is also able to pass complex combinations of 90-deg convex and concave ferromagnetic obstacles with almost any inclination regarding gravity. It requires only limited space to maneuver because turning on the spot around the rear wheel is possible. This high mobility enables the robot to access any location in the specified environment. Finally the paper analyzes the maximum payload for different types of environment complexities because this is a key feature for climbing robots and provides a security factor about the risk of falling and slipping. © 2009 Wiley Periodicals, Inc. [source]


A novel internal antenna with high gain for wireless phone

MICROWAVE AND OPTICAL TECHNOLOGY LETTERS, Issue 9 2007
Ying Liu
Abstract A novel internal antenna for synchronous code division multiple access band wireless phone is presented. Traditional internal antenna is monopole or Planar Inverted-F Antenna, which have no gain high enough in the limited space in phone. The proposed antenna is composed of two antenna elements with equal magnitude and 180° phase difference, to assure voice quality with high gain. The measured maximum gain is 2.69 dBi and maximum efficiency is 70.1% in the frequency band 450,470 MHz. © 2007 Wiley Periodicals, Inc. Microwave Opt Technol Lett 49: 2112,2114, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.22708 [source]


Improving health through youth sports: Is participation enough?

NEW DIRECTIONS FOR YOUTH DEVELOPMENT, Issue 115 2007
Michael F. Bergeron
The health benefits of engaging in regular physical activity are widely known: enhanced cardiorespiratory fitness, increased muscular strength and endurance, and favorable cholesterol and other profiles. Nevertheless, particularly in youth sports programs run by volunteer, and perhaps inadequately trained, coaches, many youth may not realize the health benefits of sports participation due to a number of factors, among them, inappropriate coach-child ratios, limited space, or mismatched expectations between coaches and those of children and their parents. There are specific strategies that can be implemented to ensure that youth receive the maximize benefits from participation in sports. These strategies are presented in the following areas: frequency, intensity, and duration; cross-training or complementary exercise; access points; utilization of space and time; nutrition; and rest. For instance, with regard to the frequency of physical activity, some sports, including soccer, basketball, and singles tennis, require extensive physical effort over an extended period of time, while others, such as baseball and football, have a lot of downtime. Thus, in order for children and youth to meet the recommendation of participating in moderate or vigorous physical activity at least four times per week, sports programs need to have opportunities for all athletes to practice hard. Finally, the author discusses the point at which participation in sports might be too much, leading to significant injuries, frustration, and resentment. [source]