Adaptive Heliostat Solar Arrays Using Shape-Optimized Compliant Mirrors

2012 ◽  
Author(s):  
Li Meng ◽  
Amy M. Bilton ◽  
Zheng You ◽  
Steven Dubowsky
Keyword(s):  
Structure Design ◽  
Two Dimensional ◽  
System Efficiency ◽  
Compliant Structure ◽  
Solar Arrays ◽  
Flat Mirror ◽  
Stiffness Profile ◽  
Solar Power Tower ◽  
Adjustment Mechanisms ◽  
The Ideal

In a Solar Power Tower (SPT) system, the ideal shape of a heliostat concentrator is a section of paraboloid which is a function of the location in the array and the incidence sun angle. This shape is difficult to achieve and limits the system efficiency. A shape-optimized compliant (SOC) design of parabolic heliostats is presented here to solve this problem. An approximation of the ideal shape is suggested to use an optimized stationary paraboloid shape which only varies with heliostat location in the array. A compliant structure design is proposed that to use a simple flat mirror with a two-dimensional tailored stiffness profile to form the required parabolic surface using adjustment mechanisms at each corner. This design is validated by numerical simulations including FEA tools, ray tracing, and classical nonlinear optimization. The annual performance shows that the SOC heliostat will substantially improve the efficiency and benefit the SPT system.

scholarly journals Composite hollow truss with multiple vierendeel panels

2013 ◽  
Vol 66 (4) ◽  
pp. 431-438
Author(s):  
Augusto Ottoni Bueno da Silva ◽  
Newton de Oliveira Pinto Júnior ◽  
João Alberto Venegas Requena
Keyword(s):  
Bearing Capacity ◽  
Failure Modes ◽  
Three Dimensional ◽  
Analytical Calculation ◽  
Two Dimensional ◽  
Shear Forces ◽  
Vertical Displacements ◽  
New System ◽  
The Ideal

The aim of this study was to evaluate through analytical calculation, two-dimensional elastic modeling, and three-dimensional plastic modeling, the bearing capacity and failure modes of composite hollow trusses bi-supported with a 15 meter span, varying the number of central Vierendeel panels. The study found the proportion span/3 - span/3 - span/3, as the ideal relationship for the truss - Vierendeel - truss lengths, because by increasing the proportion of the length occupied by the central Vierendeel panels, the new system loses stiffness and no longer supports the load stipulated in the project. Furthermore, they can start presenting excessive vertical displacements and insufficient resistance to external shear forces acting on the panels.

Two-dimensional generalizations of the Newcomb equation

1990 ◽  
Vol 43 (2) ◽  
pp. 291-310 ◽  
Author(s):  
R. L. Dewar ◽  
A. Pletzer
Keyword(s):  
Rational Surface ◽  
Cylindrical Symmetry ◽  
Two Dimensional ◽  
Transformation Theory ◽  
Continuous Symmetry ◽  
Scalar Form ◽  
Complicated Form ◽  
Dimensional Equation ◽  
Zero Frequency ◽  
The Ideal

The Bineau reduction to scalar form of the equation governing ideal zero-frequency linearized displacements from a hydromagnetic equilibrium possessing a continuous symmetry is performed in ‘universal co-ordinates’, applicable to both the toroidal and helical cases. The resulting generalized Newcomb equation (GNE) has in general a more complicated form than the corresponding one-dimensional equation obtained by Newcomb in the case of circular cylindrical symmetry, but in this cylindrical case we show that the equation can be transformed to that of Newcomb. In the two-dimensional case there is a transformation that leaves the form of the GNE invariant and simplifies the Frobenius expansion about a rational surface, especially in the limit of zero pressure gradient. The Frobenius expansion about a mode rational surface is developed and the connection with Hamiltonian transformation theory is shown. The derivations of the ideal interchange and ballooning criteria from the formalism are discussed.

Bridging Ideal and Non-Ideal Theory

2017 ◽  
Vol 66 (4) ◽  
pp. 887-902 ◽  
Author(s):  
Alexandru Volacu
Keyword(s):  
Political Theory ◽  
Ideal Theory ◽  
Two Dimensional ◽  
Current State ◽  
The World ◽  
Normative Models ◽  
The Ideal

Many of the recent methodological debates within political theory have focused on the ideal/non-ideal theory distinction. While ideal theorists recognise the need to develop an account of the transition between the two levels of theorising, no general proposal has been advanced thus far. In this article, I aim to bridge this conceptual gap. Towards this end, I first reconstruct the ideal/non-ideal theory distinction within a simplified two-dimensional framework, which captures the primary meanings usually attributed to it. Subsequently, I use this framework to provide an algorithm for the bidirectional transition between ideal and non-ideal theory, based on the incremental derivation of normative models. The approach outlined illuminates the various ways in which principles derived under highly idealised assumptions might be distorted by the circumstances of our current world and illustrates the various paths which we can pursue in moving from our current state of the world to an ideal one.

scholarly journals Transmit and Receive Array Structure Design of Two-Dimensional hybrid Phased-MIMO Radar based on Nested Array

2018 ◽  
Vol 232 ◽  
pp. 02052
Author(s):  
Tianhao Cheng ◽  
Buhong Wang ◽  
Qiaoge Liu ◽  
Jiwei Tian
Keyword(s):  
Design Method ◽  
Doa Estimation ◽  
Mimo Radar ◽  
Structure Design ◽  
Estimation Accuracy ◽  
Two Dimensional ◽  
Simulation Experiments ◽  
Virtual Array ◽  
Array Structure ◽  
Receive Array

In order to reduce the loss of Degree of Freedom (DOF) brought by the transmit subarray splitting of two-dimensional hybrid phased-MIMO radar, this paper presents a design method of transmitting and receiving array based on nested array structure. Firstly, a two-dimensional hybrid phased-MIMO radar transmitting array based on one-dimensional nested array is presented. On this basis, the receiving end is set as a nested array, and finally a virtual array and difference coarray are formed to expand the number of virtual array elements. The expansion increases the DOF of arrays while preserving the advantages of hybrid phased-MIMO radars. Simulation experiments show that compared with the traditional and coprime hybrid phased-MIMO radar, the proposed method can effectively improve the array DOF and Direction-of-Arrival (DOA) estimation accuracy.

scholarly journals The ideal strength of two-dimensional stanene may reach or exceed the Griffith strength estimate

Nanoscale ◽  
2017 ◽  
Vol 9 (21) ◽  
pp. 7055-7062 ◽  
Author(s):  
Zhe Shi ◽  
Chandra Veer Singh
Keyword(s):  
Two Dimensional ◽  
Ideal Strength ◽  
The Ideal

scholarly journals Optimize 2-D Path Planning of Mobile Robot by using ACO with Guidance Factor

2020 ◽  
Vol 9 (02) ◽  
Author(s):  
Li Wang
Keyword(s):  
Path Planning ◽  
Mobile Robot ◽  
Design Method ◽  
Target Position ◽  
Structure Design ◽  
Two Dimensional ◽  
Ant System ◽  
Planning Strategy ◽  
Research Article ◽  
System Methodology

In this research article, the path planning of a mobile robot done by using ant colony optimization (ACO) with guidance factor. A two-dimensional (2-D) threat map structure design for path planning strategy, in which threat points are fixed in the path of moving robot. The two main objective of this research; to reach the mobile robot at the target position by using optimal route using ACO strategy. Secondly, by using guidance factor all the ants of ACO arrive at the fixed targeted area. Moreover, the results of the proposed algorithm compares with the classical ant system methodology. The simulated results show that the design method has short path planning and less steady state error to reach the designated path robustly.            

scholarly journals Calculation of the aerodynamic torque in the problems of mathematical modeling of the attitude motion of spacecraft Progress

2021 ◽  
pp. 1-41
Author(s):  
Mikhail Yuryevich Belyaev ◽  
Tatiana Vladimirovna Matveeva ◽  
Vasilii Victorovich Sazonov ◽  
Victor Vasil’yevich Sazonov
Keyword(s):  
Mathematical Modeling ◽  
Fourier Series ◽  
External Surface ◽  
Geometric Model ◽  
Attitude Motion ◽  
Dimensional Sphere ◽  
Two Dimensional ◽  
Solar Arrays ◽  
Solar Orientation ◽  
Aerodynamic Torque

We describe the method of representation the aerodynamic torque in problems of mathematical modeling uncontrolled attitude motion of spacecraft Progress. The components of the torque are calculated in the nodes of the grid on the two-dimensional sphere. The calculations were based on the detailed geometric model of the spacecraft external surface. The found arrays of torque data were approximated by the segments of the Fourier series by spherical functions up to the order (8,8) inclusive. These approximations are used in the equations of attitude motion of the spacecraft. We describe the use of such equations in reconstruction of the motion of spacecraft Progress MS-07, MS-08 in the gravitational orientation mode by measurements of their angular rates and in the prognosis of electric charge from the solar arrays of the spacecraft in the mode of its single-axis solar orientation.

scholarly journals Extremely Non-Auxetic Behavior of a Typical Auxetic Microstructure Due to Its Material Properties

Materials ◽  
2021 ◽  
Vol 14 (24) ◽  
pp. 7837
Author(s):  
Mikołaj Bilski ◽  
Krzysztof W. Wojciechowski ◽  
Tomasz Stręk ◽  
Przemysław Kędziora ◽  
James N. Grima-Cornish ◽  
...  
Keyword(s):  
Symmetry Axis ◽  
Common Belief ◽  
Two Dimensional ◽  
Upper Limit ◽  
The Monte Carlo Method ◽  
Isotropic Media ◽  
Thermodynamic Conditions ◽  
The Common ◽  
Auxetic Structure ◽  
The Ideal

The re-entrant honeycomb microstructure is one of the most famous, typical examples of an auxetic structure. The re-entrant geometries also include other members as, among others, the star re-entrant geometries with various symmetries. In this paper, we focus on one of them, having a 6-fold symmetry axis. The investigated systems consist of binary hard discs (two-dimensional particles with two slightly different sizes, interacting through infinitely repulsive pairwise potential), from which different structures, based on the mentioned geometry, were formed. To study the elastic properties of the systems, computer simulations using the Monte Carlo method in isobaric-isothermal ensemble with varying shape of the periodic box were performed. The results show that all the considered systems are isotropic and not auxetic—their Poisson’s ratio is positive in each case. Moreover, Poisson’s ratios of the majority of examined structures tend to +1 with increasing pressure, which is the upper limit for two-dimensional isotropic media, thus they can be recognized as the ideal non-auxetics in appropriate thermodynamic conditions. The results obtained contradict the common belief that the unique properties of metamaterials result solely from their microstructure and indicate that the material itself can be crucial.

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