Search results for "rotation"
showing 10 items of 935 documents
Low-cost underwater navigation systems by multi-pressure measurements and AHRS data
2017
This paper deals with accurate navigation for underwater remotely operated vehicles. A feasibility study for a multi-pressure device to be mounted on an ROV is presented. The device can provide accurate estimates of a ROV orientation and angular speed. It is based on the well-known total pressure principle, also used in a Pitot tube, and allows reconstruction of static and dynamic pressures, which in turn provide good estimates of the ROV's orientation and rotational speed, respectively. An appealing feature of the proposed device is its ability to provide accurate estimates even for low-speed movements.
Head and Body Coordination during Locomotion and Complex Movements
1994
Publisher Summary This chapter discusses theory in which it is argued that during complex movements, the head is stabilized intermittently under the control of gaze, and that this stabilization allows the head to serve as an inertial guidance platform for the control of multilimb movement. The otolithic organs, sacculus and utriculus, are inertial detectors of linear acceleration of the head in the plane of their macula. It is well established that in normal gravity conditions, although the perceived gravitational vertical deviates from the objective vertical by a few degrees, gravitational reference is used not only for posture but also for perceptual tasks that involve orientation in spac…
Experimental Investigation of Stall and Surge in a Multistage Compressor
2016
Flow instability conditions, in particular during surge and stall phenomena, have always influenced the operational reliability of turbo-compressors and have attracted significant interest resulting in extensive literature. Nowadays, this subject is still one of the most investigated because of its high relevance on centrifugal and axial compressor operating flow range, performance and efficiency. Many researchers approach this important issue by developing numerical models, whereas others approach it through experimental studies specifically carried out in order to better comprehend this phenomenon. The aim of this paper is to experimentally analyze the stable and unstable operating condit…
A Flux and Speed Observer for Sensorless SPIM Applications
2010
It is usual to find single-phase induction motor (SPIM) in several house, office, shopping, farm, and industry appliances, which is become more sophisticated and requires the development of high performance alternatives to drive a SPIM. All proposed strategies to improve the performance SPIM need the evaluation of the rotational speed or position information. Since the use of conventional sensors to measure the rotational speed cannot be justified for SPIM applications, the adoption of a sensorless strategy is a more reasonable option for these cases. This paper presents a flux and speed observer for sensorless applications involving SPIMs. The performance of the proposed observer is verifi…
A discussion on variants of stand-alone electric powerplant equipped with transverse flux generators
2015
The paper discussed several designed variants of TFG with different number of poles, speed and dimensional coefficients starting from two base module variants with a rated power of 8kW and 11 kW respectively. The proposed layout came from reluctance one and it is suitable to equipped stand-alone electric power plant being a proper solution for isolated farms. The influence of large number of poles on torque density values obtained at low rotational speed is discussed in paper.
On the assessment of power consumption and critical impeller speed in vortexing unbaffled stirred tanks
2017
Abstract Unbaffled stirred tanks are increasingly recognized as a viable alternative to common baffled tanks for a number of processes and bio-processes where the presence of baffles is undesirable. Notwithstanding the increasing industrial interest towards unbaffled tanks, available experimental information on their behaviour is still very poor, even for important parameters such as mechanical power drawn and critical impeller speed (Ncr) at which the transition between non-aerated (sub-critical regime) and aerated (super-critical regime) conditions occurs. In this work the influence of Reynolds and Froude numbers on power consumption characteristics of unbaffled stirred tanks is presented…
Definition of a laboratory optimization protocol for road bitumen improved with recycled tire rubber
2012
Abstract Bearing in mind the need to answer one of the most frequent needs for civil construction, in general, and major project such as road infrastructures in particular, this paper presents the results of a laboratory experimental study in order to evaluate the performance improvement that is possible to achieve when modifying road bitumen with CRM (Crumb Rubber Modifier) from discarded tire rubber (TR), using a Wet Process. The environmental advantage is double, since the aim of the research is to obtain high performance road bitumen thanks to the re-use of a discarded material, such as the rubber tires, which otherwise would be dumped in scrap-yard. In particular, this experimental stu…
On the induced drag reduction due to propeller-wing interaction
1995
AbstractThe aerodynamic interaction between a wing and a couple of propellers in tractor configuration is investigated by means of a model based on the lifting line concept and under the assumption of quasi-steady incompressible motion of inviscid fluid. The ways the propellers influence the wing performances, particularly the induced drag, are analysed. It turns out that the lift increase and the possible drag reduction depend strongly on the direction of the blade rotation and on the propeller distances from midspan, and result from two main effects: the direct propeller induction on the wing and the modification of the lift distribution along the span. An additional nonlinear (mixed) con…
Reduction of parameters in failure criteria for multiaxial Random Fatigue
1990
In the paper some equivalent methods of determining the expected fatigue fracture plane position have been presented. These methods make use of elements of a full linear rotation group. Replacing nine direction cosines, mutually related, by three Euler angles we obtain a reduced number of parameters used for the description of the excepted fatigue fracture plane position. New mathematical forms of the fatigue criteria with a reduced number of independent parameters have been presented well.
CAMELINA SATIVA AS A CROP FOR DIVERSIFICATION OF AGRICULTURE AND AS A PRODUCER OF HIGH QUALITY OIL
2007
‘Camelina sativa’ is one of the oldest oil crops in Europe. Growing areas were reduced dramatically in 20-40-ties of the last century. Low price of rape oil and unclear composition of camelina oil were primary reasons of this process. Nevertheless, last years ‘Camelina sativa' attracted a great interest of scientists and oil processors as a crop for diversification of agriculture and, in the same time, for producing of the high quantity and quality oil for biofuel, feeding, food, and pharmacy (source of a-linolenic acid, linoleic acid and vitamins, especially E). In Latvia ‘Camelina sativa' is spread as a wild form but for the agriculture it is a new crop.The potential of me of ‘Camelina sa…