Concept of Internal Momentum Absorber Structure to Reduce Impact During Accidents

2019 ◽  
pp. 144-149
Author(s):  
Mandip Kumar Nar ◽  
Prabhjeet Singh ◽  
Paprinder Singh
Keyword(s):  
Internal Momentum ◽  
Absorber Structure

The Multitude and the Many-Headed Hydra: Autonomist Marxist Theory and Labor History

2013 ◽  
Vol 83 ◽  
pp. 170-190 ◽  
Author(s):  
Verity Burgmann
Keyword(s):  
Labor History ◽  
Marxist Theory ◽  
Capitalist Development ◽  
Internal Momentum ◽  
Autonomist Marxism ◽  
The World ◽  
The Many

AbstractThe autonomist Marxist critique of determinist Marxism offers even more valuable insights for labor historians than that mounted by earlier antideterminists, such as Sartre and Thompson, who emphasized proletarian agency to counter determinist orthodoxy in which the accumulative logic of capital unilaterally shapes the world. Autonomist Marxism is more far-reaching. It places labor at the very beginning of the labor-capital dialectic: Labor can exist independently of capital, but capital needs to command labor to ensure profit; therefore, capitalist development does not occur due to internal momentum but in reaction to labor's tendency to unloose itself from capital. Linebaugh and Rediker offer a similar hypothesis in exploring the myth of the many-headed hydra—and demonstrate the fruitfulness of such an approach. By contrast, the notion of the multitude in Hardt and Negri'sEmpirehas not been well received by labor historians due to its inexplicable abstraction when read in isolation from other autonomist texts. This article attempts to rescue the ideas of autonomist Marxist philosophers, especially Toni Negri, from the enormous condescension of labor history.

Orientation Control Using Oscillating Momentum Wheels

2015 ◽  
Author(s):  
Shaoqian Wang ◽  
Amir H. Ghasemi ◽  
Joshua L. Evans ◽  
T. Michael Seigler
Keyword(s):  
Closed Loop ◽  
Inverse Dynamics ◽  
The Body ◽  
Rotational Dynamics ◽  
Fixed Frequency ◽  
Internal Momentum ◽  
Control Techniques ◽  
Sinusoidal Oscillations ◽  
Fixed Axis ◽  
Inverse Dynamics Problem

This paper addresses the problem of controlling a rigid body’s orientation by actuating sinusoidal oscillations of internal momentum wheels. We consider the rotational dynamics of a rigid body having three momentum wheels (one for each body-fixed axis) that are attached to the body by springs. Each wheel is actuated by an internal sinusoidal torque of fixed frequency. The frequency of all sinusoidal torques is equal, but the amplitudes and phases can be varied independently. We analyze the inverse-dynamics problem of determining the amplitudes and phases for each sinusoidal torque such that a desired orientation is achieved. We then present two closed-loop orientation controllers based on this analysis. Numerical simulations demonstrate the effectiveness of the control techniques.

scholarly journals Two-layered Dual-band Perfect Metamaterial Absorber at K band Frequency

2018 ◽  
Vol 7 (2) ◽  
pp. 25-27
Author(s):  
M. C. Tran ◽  
T. T. H. Phuong
Keyword(s):  
Metamaterial Absorber ◽  
Dual Band ◽  
Material Structure ◽  
Perfect Absorption ◽  
Band Frequency ◽  
Absorption Frequency ◽  
Dielectric Layers ◽  
Absorber Structure ◽  
Perfect Metamaterial Absorber ◽  
K Band

This paper presents a study of a novel absorber structure based on two-dielectric-layers, two perfect absorption frequency bands at K band (f1 = 26.5 GHz and f2 = 28.6 GHz) go under observance. The study of the dependence of absorption and frequency on relative distance between the layers of material and the material structure parameters are discussed. 

Polarization angle independent metamaterial absorber based on circle-shaped resonators with interference theory

2015 ◽  
Vol 29 (30) ◽  
pp. 1550188
Author(s):  
Furkan Dincer ◽  
Muharrrem Karaaslan ◽  
Oguzhan Akgol ◽  
Emin Unal ◽  
Cumali Sabah
Keyword(s):  
Wide Band ◽  
Metamaterial Absorber ◽  
Polarization Angle ◽  
Absorption Mechanism ◽  
Perfect Absorption ◽  
Microwave Frequencies ◽  
Simple Geometry ◽  
Absorber Structure ◽  
Perfect Metamaterial Absorber ◽  
Source Wave

We theoretically and numerically designed a perfect metamaterial absorber at microwave frequencies. The proposed design has a very simple geometry, wide band properties and provides perfect absorption for all polarization angles which is one of the most desired properties for an absorber structure to be used in the applications where the source polarization is unknown. In order to explain the absorption mechanism both numerical and theoretical analyses are carried out. Designed structure offers a perfect absorption at around 9.8 GHz. The resonance frequency does not change depending on the source wave polarization. In addition, it can be easily reconfigured for THz and infrared regimes for different applications such as sensors, defense systems and stealth technologies.

Metamaterial-Plasmonic Absorber Structure for High Efficiency Amorphous Silicon Solar Cells

Nano Letters ◽  
2011 ◽  
Vol 12 (1) ◽  
pp. 440-445 ◽  
Author(s):  
Yang Wang ◽  
Tianyi Sun ◽  
Trilochan Paudel ◽  
Yi Zhang ◽  
Zhifeng Ren ◽  
...  
Keyword(s):  
Solar Cells ◽  
Amorphous Silicon ◽  
High Efficiency ◽  
Silicon Solar Cells ◽  
Absorber Structure

Economic Potential of Innovative Receiver Concepts With Different Solar Field Configurations for Supercritical Steam Cycles

2011 ◽  
Author(s):  
Cs. Singer ◽  
R. Buck ◽  
R. Pitz-Paal ◽  
H. Mu¨ller-Steinhagen
Keyword(s):  
Molten Salt ◽  
Cost Reduction ◽  
Reduction Potential ◽  
Power Level ◽  
Direct Absorption ◽  
Reference Case ◽  
Levelized Cost Of Electricity ◽  
Absorber Structure ◽  
Solar Field ◽  
Lateral Area

The cost reduction potential of solar power towers (SPT) is an important issue concerning its market introduction. Raising the steam process temperature and pressure can lead to a cost reduction due to increased overall plant efficiency. Thus, for new receiver configurations a supercritical steam cycle operated at 300 bar / 600°C / 610°C live steam conditions was assumed. The considered systems include innovative direct absorption receivers, either with conventional or beam down heliostat field layouts. For the beam down option the receiver is assumed to be a cylindrical vessel with a flow-through porous absorber structure at the internal lateral area of the cylinder. The direct absorption receiver option consists of a cylindrical barrel with downwards oriented aperture, whose absorber structure at the internal lateral area is cooled by a molten salt film. For the assessment, CFD based methods were developed to be able to examine the receiver efficiency characteristics. Based on the receiver thermal efficiency characteristics and the solar field characteristics the annual performance is evaluated using hourly time series. The assessment methodology is based on the European Concentrated Solar Thermal Roadmap (ECOSTAR) study and enables the prediction of the annual performance and the levelized cost of electricity (LCOE). Applying appropriate cost assumptions from literature the LCOE were estimated for each considered SPT concept and compared to tubular receiver concepts with molten salt and liquid metal cooling. The power level of the compared concepts and the reference case is 200 MWel. The sensitivity of the specific cost assumptions was analyzed. No detailed evaluation was done for the thermal storage, but comparable storage utilization and costs were assumed for all cases. At optimized plant parameters the results indicate a LCOE reduction potential of up to 0.5% for beam down and of up to 7.2% for the direct absorption receiver compared to today’s state of the art molten salt solar tower technology.

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