The heat treatment of medium carbon steels in the ferrite plus austenite range

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Parameterization of Stabilizing Linear Coherent Quantum Controllers

This paper is concerned with application of the classical Youla-Ku\v{c}era parameterization to finding a set of linear coherent quantum controllers that stabilize a linear quantum plant. The plant and controller are assumed to represent open quantum harmonic oscillators modelled by linear quantum stochastic differential equations. The interconnections between the plant and the controller are assumed to be established through quantum bosonic fields. In this framework, conditions for the stabilization of a given linear quantum plant via linear coherent quantum feedback are addressed using a stable factorization approach. The class of stabilizing quantum controllers is parameterized in the frequency domain. Also, this approach is used in order to formulate coherent quantum weighted $H_2$ and $H_\infty$ control problems for linear quantum systems in the frequency domain. Finally, a projected gradient descent scheme is proposed to solve the coherent quantum weighted $H_2$ control problem.Comment: 11 pages, 4 figures, a version of this paper is to appear in the Proceedings of the 10th Asian Control Conference, Kota Kinabalu, Malaysia, 31 May - 3 June, 201

Covariance Dynamics and Entanglement in Translation Invariant Linear Quantum Stochastic Networks

This paper is concerned with a translation invariant network of identical quantum stochastic systems subjected to external quantum noise. Each node of the network is directly coupled to a finite number of its neighbours. This network is modelled as an open quantum harmonic oscillator and is governed by a set of linear quantum stochastic differential equations. The dynamic variables of the network satisfy the canonical commutation relations. Similar large-scale networks can be found, for example, in quantum metamaterials and optical lattices. Using spatial Fourier transform techniques, we obtain a sufficient condition for stability of the network in the case of finite interaction range, and consider a mean square performance index for the stable network in the thermodynamic limit. The Peres-Horodecki-Simon separability criterion is employed in order to obtain sufficient and necessary conditions for quantum entanglement of bipartite systems of nodes of the network in the Gaussian invariant state. The results on stability and entanglement are extended to the infinite chain of the linear quantum systems by letting the number of nodes go to infinity. A numerical example is provided to illustrate the results.Comment: 11 pages, 3 figures, submitted to the 54th IEEE Conference on Decision and Control, December 15-18, 2015, Osaka, Japa

Characterization of Plastic Deformation Evolution in Single Crystal and Nanocrystalline Cu During Shock by Atomistic Simulations

The objective of this dissertation is to characterize the evolution of plastic deformation mechanisms in single crystal and nanocrystalline Cu models during shock by atomistic simulations. Molecular dynamics (MD) simulations are performed for a range of particle velocities from 0.5 to 1.7 km/s and initial temperatures of 5, 300 and 600 K for single crystal models as well as particle velocities from 1.5 to 3.4 km/s for nanocrystalline models with grain diameters of 6, 11, 16 and 26 nm. For single crystal models, four different shock directions are selected, \u3c100\u3e, \u3c110\u3e, \u3c111\u3e and \u3c321\u3e, and dislocation density behind the shock wave front generally increases with increasing particle velocity for all shock orientations. Plastic relaxation for shock in the \u3c110\u3e, \u3c111\u3e and \u3c321\u3e directions is primarily due to a reduction in the Shockley partial dislocation density. In contrast, plastic relaxation is limited for shock in the \u3c100\u3e orientation. This is partially due to the emergence of sessile stair-rod dislocations with Burgers vectors of 1/3\u3c100\u3e and 1/6\u3c110\u3e due to the reaction of Shockley partial dislocations with twin boundaries and stacking fault intersections. For \u3c100\u3e shock, FCC Cu is uniaxially compressed towards the BCC structure behind the shock wave front; this process is more favorable at higher shock pressures and temperatures. For particle velocities above 0.9 km/s, regions of HCP crystal structure nucleate from uniaxially compressed Cu. Free energy calculations proves that the nucleation and growth of these HCP clusters are an artifact of the embedded-atom interatomic potential. In addition, simulated x-ray diffraction line profiles are created for \u3c100\u3e shock models of single crystal Cu at the Hugoniot state. Generally, peak broadening in the x-ray diffraction line profiles increases with increasing particle velocity. For nanocrystalline models, the compression of the FCC lattice towards the BCC structure is more apparent at particle velocity of 2.4 km/s, and at this particle velocity, the atomic percentage of BCC structure increases with increasing grain size. The observation of BCC structure strongly depends on grain orientation; grains with \u3c100\u3e directions closely aligned with the shock loading direction show a higher percentage of BCC structure

Robust Mean Square Stability of Open Quantum Stochastic Systems with Hamiltonian Perturbations in a Weyl Quantization Form

This paper is concerned with open quantum systems whose dynamic variables satisfy canonical commutation relations and are governed by quantum stochastic differential equations. The latter are driven by quantum Wiener processes which represent external boson fields. The system-field coupling operators are linear functions of the system variables. The Hamiltonian consists of a nominal quadratic function of the system variables and an uncertain perturbation which is represented in a Weyl quantization form. Assuming that the nominal linear quantum system is stable, we develop sufficient conditions on the perturbation of the Hamiltonian which guarantee robust mean square stability of the perturbed system. Examples are given to illustrate these results for a class of Hamiltonian perturbations in the form of trigonometric polynomials of the system variables.Comment: 11 pages, Proceedings of the Australian Control Conference, Canberra, 17-18 November, 2014, pp. 83-8

SEPARATING PRODUCT FAMILY DESIGN OPTIMIZATION PROBLEMS

In order to improve productivity and reduce costs, manufacturing firms use product families to provide variety while maintaining economies of scale. In a competitive marketplace, designing a successful product family requires considering both customer preferences and the actions of other firms. This dissertation will conduct fundamental research on how to design products and product families in the presence of competition. We consider both single product and product family design problems. We use game theory to construct a model that includes the competition's product design decisions. We use separation, a problem decomposition approach, to replace complex optimization problems with simpler problems and find good solutions more efficiently. We study the well-known universal electric motor problem to demonstrate our approaches. This dissertation introduces the separation approach, optimizes product design with competition, models product family design under competition as a two-player zero-sum game, and models product family design with design and price competition as a two-player mixed-motive game. This dissertation formulates novel product design optimization problems and provides a new approach to solve these problems

A Reminiscence of Stillness

Der Fluss Zayandeh Rud (›lebensspendender Fluss‹) in Isfahan, Iran, ist Ausgangspunkt für ein Gespräch mit und eine Reise zu sich selbst. Wasser als persisches Symbol für Reinheit und eine Verbindung von Himmel und Erde prägt die Wahrnehmung dieses Stroms, der in den letzten Jahren immer öfter austrocknete.The river Zayandehrood (‘life-giving river’) in Isfahan, Iran, is the starting point for a journey to oneself. Water as a Persian symbol for purity and as a connection between heaven and earth shapes the perception of this river, which has dried up more and more often in recent years