scholarly journals Sharp Rellich–Leray inequality with any radial power weight for solenoidal fields

Author(s):  
Naoki Hamamoto
Keyword(s):  
Author(s):  
A. J. Atkins

This paper outlines the essential requirements for light car transmissions and shows how they differ from those suitable for larger cars. Apart from the obvious size and weight limitations these transmissions must be sufficiently flexible to cope with the usually lower power/weight factors. They must have less power losses and be produced at a cost in proportion to the price of the cars. Comment is made on the intrinsic problems of designing transmissions that are sturdy enough to accept heavy duty and yet are lightweight, efficient, and trouble free while remaining within the price range of the motorist who expects economy with adequate performance.


Agriculture ◽  
2018 ◽  
Vol 8 (12) ◽  
pp. 186 ◽  
Author(s):  
Tatevik Yezekyan ◽  
Francesco Marinello ◽  
Giannantonio Armentano ◽  
Samuele Trestini ◽  
Luigi Sartori

Machine functional parameters define fleet composition and management and, thus, play an important role in economic and environmental performance. Large availability of programming methods and decision support systems are available in the market, however, there is still a lack of applicative tools to forecast the perceived and necessary technical parameters and machinery price options to complete tasks. In the current research, most correlated functional parameters for four group of seeding machines were determined with the application of linear and multiple linear regression analyses. Power, weight, working width, number of rows, and list price were studied, and reference equations were developed for seed drills, precision, combined and no-tillage planters. Two statistical analyses models were, therefore, developed for each of the groups in order to allow evaluation and prediction of performance and cost, thus contributing to the selection process optimisation and perceived choice of the needed implement.


Electronics ◽  
2020 ◽  
Vol 9 (1) ◽  
pp. 168 ◽  
Author(s):  
Hany S. Hussein ◽  
Mohamed Hagag ◽  
Mohammed Farrag

An efficient optical modulation technique for multi-input multi-output (MIMO) orthogonal frequency division multiplexing (OFDM) visible light communication system is proposed in this paper. The proposed modulation technique is termed as extended spatial-index light-emitting diode (LED) modulation. In the proposed technique, the indices (the spatial domain) of the LEDs are exploited in a dynamic style to not only get rid of the optical OFDM time-domain ( OFDM t d ) shaping problem but also to expand the LED indices spatial modulation domain. The indices of the active LEDs in the proposed technique are changed from the two LEDs active situation to the situation where all or several LEDs are active. Moreover, within the selected active LED indices, the power weight distribution and the positions of the OFDM components are varied to expand the resultant spatial domain. Therefore, the proposed technique offers a considerable spectral efficiency improvement over the up-to-date LED index OFDM modulation schemes even with a lower number of LEDs. The key idea of the proposed technique is to maximize the LEDs’ indices spatial position (spatial domain) utilization, where both the power weight allocation and the positions of the complex OFDM time domain components are varying several times over the same active LED indices combination, which improve the optical system spectral efficiency. The simulation results asserted the superiority of the proposed technique, as it improves both the average bit error rate (ABER) and the achievable data rate (R) compared with existing up-to-date OFDM-LED index modulations with even lower computational complexity.


2014 ◽  
Vol 658 ◽  
pp. 541-546 ◽  
Author(s):  
Mihai Avram ◽  
Victor Constantin ◽  
Constantin Bucşan ◽  
Daniel Besnea ◽  
Alina Spanu

Pneutronic systems come with a series of advantages that are natural to working with compressed air, such as the large power/weight ratio of pneumatic actuators, easy and affordable installation and maintenance as well as being clean working systems. However, due to working with compressed air, there are a series of issues, such as static and transient nonlinear behavior, mostly due to the high compressibility of air. Thus, the behavior of such systems is hard to control, especially in terms of precision positioning. The paper deals with proposing three hardware configurations of pneutronic positioning systems in order to assure the imposed positioning accuracy in the presence of disturbances and the preservation in time of the obtained position.


1981 ◽  
Vol 9 (8) ◽  
pp. 133-137
Author(s):  
John P. O'Shea
Keyword(s):  

Author(s):  
J. Shapiro ◽  
A. Levy

High power/weight ratio and low SFC are the most important requirements for an airborne engine. This may be achieved by a gas turbine engine with an intermediate heat exchanger, combined with a double-decked compressor-turbine design. In this engine, the specific fuel consumption is minimal at 70% of maximum power output for best fuel economy in helicopter engines. The additional weight, due to its design, is compensated by fuel saved in less than one hour flight for a 926 kW cruise power engine.


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