Inverse Methods for Characterization of Contact Areas in Mechanical Systems.
Abstract not provided.
Fronk, Matthew↗
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Micro electro mechanical system optical switching
The present disclosure includes apparatus, system, and method embodiments that provide micro electo mechanical system optical switching and methods of manufacturing switches. For example, one optical switch embodiment includes at least one micro electro mechanical system type pivot mirror structure disposed along a path of an optical signal, the structure having a mirror and an actuator, and the mirror having a pivot axis along a first edge and having a second edge rotatable with respect to the pivot axis, the mirror being capable of and arranged to be actuated to pivot betweeen a position parallel to a plane of an optical signal and a position substantially normal to the plane of the optical signal.
42 ENGINEERING↗
Dynamics of disordered mechanical systems with large connectivity, free probability theory, and quasi-Hermitian random matrices
Disordered mechanical systems with high connectivity represent a limit opposite to the more familiar case of disordered crystals. Individual ions in a crystal are subjected essentially to nearest-neighbor interactions. In contrast, the systems studied in this paper have all their degrees of freedom coupled to each other. Thus, the problem of linearized small oscillations of such systems involves two full positive-definite and non-commuting matrices, as opposed to the sparse matrices associated with disordered crystals. Consequently, the familiar methods for determining the averaged vibrational spectra of disordered crystals, introduced many years ago by Dyson and Schmidt, are inapplicable for highly connected disordered systems. In this paper we apply random matrix theory (RMT) to calculate the averaged vibrational spectra of such systems, in the limit of infinitely large system size. At the heart of our analysis lies a calculation of the average spectrum of the product of two positive definite random matrices by means of free probability theory techniques. We also show that this problem is intimately related with quasi-hermitian random matrix theory (QHRMT), which means that the ‘hamiltonian’ matrix is hermitian with respect to a non-trivial metric. This extends ordinary hermitian matrices, for which the metric is simply the unit matrix. The analytical results we obtain for the spectrum agree well with our numerical results. The latter also exhibit oscillations at the high-frequency band edge, which fit well the Airy kernel pattern. We also compute inverse participation ratios of the corresponding amplitude eigenvectors and demonstrate that they are all extended, in contrast with conventional disordered crystals. Finally, we compute the thermodynamic properties of the system from its spectrum of vibrations. In addition to matrix model analysis, we also study the vibrational spectra of various multi-segmented disordered pendula, as concrete realizations of highly connected mechanical systems. A universal feature of the density of vibration modes, common to both pendula and the matrix model, is that it tends to a non-zero constant at vanishing frequency.
71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗
Nonlinear quantum-mechanical system associated with Sine-Gordon equation in (1 + 2) dimensions
Despite the fact that it is not integrable, the (1 + 2)-dimensional Sine-Gordon equation has N-soliton solutions, whose velocities are lower than the speed of light (c = 1), for all N ≥ 1. Based on these solutions, a quantum-mechanical system is constructed over a Fock space of particles. The coordinate of each particle is an angle around the unit circle. U, a nonlinear functional of the particle number-operators, which obeys the Sine-Gordon equation in (1 + 2) dimensions, is constructed. Its eigenvalues on N-particle states in the Fock space are the slower-than-light, N-soliton solutions of the equation. A projection operator (a nonlinear functional of U), which vanishes on the single-particle subspace, is a mass-density generator. Its eigenvalues on multi-particle states play the role of the mass density of structures that emulate free, spatially extended, relativistic particles. The simplicity of the quantum-mechanical system allows for the incorporation of perturbations with particle interactions, which have the capacity to “annihilate” and “create” solitons – an effect that does not have an analog in perturbed classical nonlinear evolution equations.
71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗
Scaling of volume to surface ratio and doubling time in growing unicellular organisms: Do cells appear quantum-mechanical systems?
The scaling of physical and biological characteristics of the living organisms is a basic method for searching of new biophysical laws. In series of previous studies the author showed that in Poikilotherms, Mammals and Aves, the volume to surface ratio V×S{sup −1} (m) of organisms is proportional to their generation time T{sub gt}(s) via growth rate v (m s{sup −1}): V×S{sup −1} = v{sub gr}×T{sup r}. The power and the correlation coefficients are near to 1.0. Aim of this study is: i) to prove with experimental data the validity of the above equation for Unicellular organisms and ii) to show that perhaps, the cells are quantum-mechanical systems. The data for body mass M (kg), density ρ (kg/m{sup 3}), minimum and maximum doubling time T{sub dt} (s) for 50 unicellular organisms are assembled from scientific sources, and the computer program ‘Statistics’ is used for calculations. In result i) the analytical relationship from type: V×S{sup −1} = 4.46⋅10{sup −11}×T{sub dt} was found, where v{sub gr} = 4.46×10{sup −11} m/s and ii) it is shown that the products between cell mass M, cell length expressed by V/S ratio and growth rate v{sub gr} satisfied the Heisenberg uncertainty principle i.e. the inequalities V/S×M×v{sub gr}>h/2π and T{sub dt}×M×v{sub gr}{sup 2}>h/2π are valid, where h= 6.626×10{sup −34} J⋅s is the Planck constant. This rise the question: do cells appear quantum-mechanical systems?.
71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗
Mechanical systems with closed orbits on manifolds of revolution
We study natural mechanical systems describing the motion of a particle on a two-dimensional Riemannian manifold of revolution in the field of a central smooth potential. We obtain a classification of Riemannian manifolds of revolution and central potentials on them that have the strong Bertrand property: any nonsingular (that is, not contained in a meridian) orbit is closed. We also obtain a classification of manifolds of revolution and central potentials on them that have the 'stable' Bertrand property: every parallel is an 'almost stable' circular orbit, and any nonsingular bounded orbit is closed. Bibliography: 14 titles.
97 MATHEMATICS AND COMPUTING↗
Assessing the State of Mechanical Systems of Different Complexity
Abstract—The use of information theory to assess the state of mechanical systems of different complexity is considered.
42 ENGINEERING↗
Informational Model of State Change in a Mechanical System
The use of information theory to formulate an informational model of the change in state of mechanical systems is considered. By that means, models of the change in state of system components may be developed for different operating conditions. In regions of the system’s state space corresponding to critical values, the probability of a fault may be determined.
42 ENGINEERING↗
Insulated Concrete Form Walls Integrated With Mechanical Systems in a Cold Climate Test House
Transitioning from standard light frame to a thermal mass wall system in a high performance home will require a higher level of design integration with the mechanical systems. The much higher mass in the ICF wall influences heat transfer through the wall and affects how the heating and cooling system responds to changing outdoor conditions. This is even more important for efficient, low-load homes with efficient heat pump systems in colder climates where the heating and cooling peak loads are significantly different from standard construction. This report analyzes a range of design features and component performance estimates in an effort to select practical, cost-effective solutions for high performance homes in a cold climate. Of primary interest is the influence of the ICF walls on developing an effective air sealing strategy and selecting an appropriate heating and cooling equipment type and capacity. The domestic water heating system is analyzed for costs and savings to investigate options for higher efficiency electric water heating. A method to ensure mechanical ventilation air flows is examined. The final solution package includes high-R mass walls, very low infiltration rates, multi-stage heat pump heating, solar thermal domestic hot water system, and energy recovery ventilation. This solution package can be used for homes to exceed 2012 International Energy Conservation Code requirements throughout all climate zones and achieves the DOE Challenge Home certification.
32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATI↗
Insulated Concrete Form Walls Integrated With Mechanical Systems in a Cold Climate Test House
Transitioning from standard light frame to a thermal mass wall system in a high performance home will require a higher level of design integration with the mechanical systems. The much higher mass in the ICF wall influences heat transfer through the wall and affects how the heating and cooling system responds to changing outdoor conditions. This is even more important for efficient, low-load homes with efficient heat pump systems in colder climates where the heating and cooling peak loads are significantly different from standard construction. This report analyzes a range of design features and component performance estimates in an effort to select practical, cost-effective solutions for high performance homes in a cold climate.
32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATI↗
INVESTIGATION OF TITANIUM BONDED GRAPHITE FOAM COMPOSITES FOR MICRO ELECTRONIC MECHANICAL SYSTEMS (MEMS) APPLICATIONS
PiMEMS Inc. (Santa Barbara, CA) in collaboration with ORNL investigated the use of Titanium Bonded Graphite Foam Composites (TBGC) for thermal mitigation in Micro Electronic Mechanical Systems (MEMS) applications. Also considered were potentially new additive manufacturing routes to producing novel high surface area micro features and diverse shaped heat transfer components for numerous lightweight MEMs applications.
36 MATERIALS SCIENCE↗
High-bandwidth Dynamic Load Emulation of Mechanical Systems using Electric Drives
Machine drives are versatile systems that can be programmed to emulate a variety of mechanical loads. In this paper, we walk through the modeling and control framework of a shaft-coupled dual-motor drive system that is programmed to emulate a fictitious mechanical system. We quantitatively evaluate the control performance of such a system and derive a theoretical limit that explains its inaccuracy at high operating frequencies. To overcome this problem, we propose an alternate control structure that achieves the same control objective at high frequencies as well. After suitable adjustments are made to the controller, we validate its performance using simulation results.
machine drives ,load emulation, speed-torque chara↗
Statistical physics of black holes as quantum-mechanical systems
Some basic features of black-hole statistical mechanics are investigated, assuming that black holes respect the principles of quantum mechanics. Care is needed in defining an entropy S bh corresponding to the number of microstates of a black hole, given that the black hole interacts with its surroundings. An open question is then the relationship between this entropy and the Bekenstein-Hawking entropy S BH . For a wide class of models with interactions needed to ensure unitary quantum evolution, these interactions produce extra energy flux beyond that predicted by Hawking. Arguments are then presented that this results in an entropy S bh that is smaller than S BH . Correspondingly, in such scenarios equilibrium properties of black holes are modified. In this work, we examine questions of consistency of such an inequality; if it is not consistent, that provides significant constraints on models for quantum-mechanical black hole evolution.
79 ASTRONOMY AND ASTROPHYSICS↗
Heat control in opto-mechanical system using quantum non-classicality
Cooling of matter to the quantum ground state is a primary directive of quantum control. In other words, to extract entropy from a quantum system, efficient indirect quantum measurements may be implemented. The main objective is the cooling of the oscillator either to its motional ground state or to non-classical states, such as low-number Fock states, squeezed states or entangled states. It is shown that the use of quantum control procedure is better choice for even experimental realizations because it leads to a squeezed steady state with less than one phonon on average. The steady state of system corresponds to cooling of the system.
71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗
Understanding and controlling lithium morphology in solid polymer and gel polymer systems: mechanisms, strategies, and gaps
Lithium metal anode promises the highest theoretical energy density and may enable high energy designs such as lithium–sulfur and lithium–air batteries. However, stable lithium plating and stripping remains a challenge in all electrolyte systems including liquids, polymers, and ceramic electrolytes. In this perspective, we examine literature studies of lithium morphologies in solid polymer and gel polymer systems and compare that with well-studied liquid electrolytes. In solid polymer electrolytes, current density and mechanical properties are both governing parameters for lithium morphology, differing from conventional liquid electrolytes. Stable lithium electrodeposition may be accomplished by a polymer electrolyte with good stiffness operating at significantly lower current densities than its limiting current density, which is defined by the Sand equation. In gel polymer electrolytes, the reported lithium morphology is more similar to that in liquid electrolytes, suggesting similar nucleation and growth mechanisms. Based on experimental evidence and theoretical guidance, current strategies to control lithium morphology in solid polymer and gel polymer electrolytes are summarized. The limitations of these strategies are discussed. In particular, we note the knowledge gap in understanding the solid electrolyte interphase in solid polymer systems and the critical role it can play in regulating lithium morphologies.
36 MATERIALS SCIENCE↗
Mechanical systems and kinematics
Kinematics is the study of how motion is achieved without reference to the forces that create the motion. This includes the basic structures of all robotic systems, such as links and joints, as well as their mathematical representations. This chapter will provide a brief overview of the types of motion used in additive manufacturing (AM) systems, as well as the mathematical equations that govern them. Rotations are explained using both Euler rotations and quaternions. Combined rotation and translations are shown using homogeneous transform matrices. The robot Jacobian, which relates joint velocities to the end effector translational velocities, is explained with an example calculation. This section will give the reader the basic mathematical foundation in kinematics that is necessary to understand the mechanical underpinnings of path planning for AM systems.
Wang, Peter↗
Integrated Mechanical System Pods (CRADA Final Report)
LBNL provided input to setting the requirements related to indoor air quality and contributed to the development of metrics and test plans to evaluate prototypes of the mechanical pods, which were developed by other members of the project team. The testing of prototypes was conducted by and at Syracuse University, another project partner. LBNL also collaborated with RMI to develop a basic plan for data collection when the pods are deployed for field testing in Phase 2.
32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATI↗
MAcro-Electro-Mechanical Systems (MÆMS) based concept for microwave beam steering in reflectarray antennas
We present a new approach to perform beam steering in reflecting type apertures such as reflectarray antennas. The proposed technique exploits macro-scale mechanical movements of parts of the structure to achieve two-dimensional microwave beam steering without using any solid-state devices or phase shifters integrated within the aperture of the antenna. The principles of operation of this microwave beam steering technique are demonstrated in an aperture occupied by ground-plane-backed, sub-wavelength capacitive patches with identical dimensions. We demonstrate that by tilting the ground plane underneath the entire patch array layer, a phase shift gradient can be created over the aperture of the reflectarray that determines the direction of the radiated beam. Changing the direction and slope of this phase shift gradient on the aperture allows for performing beam steering in two dimensions using only one control parameter (i.e., tilt vector of the ground plane). A proof-of-concept prototype of the structure operating at X-band is designed, fabricated, and experimentally characterized. Experiments demonstrate that small mechanical movements of the ground plane (in the order of 0.05λ{sub 0}) can be used to steer the beam direction in the ±10° in two dimensions. It is also demonstrated that this beam scanning range can be greatly enhanced to ±30° by applying this concept to the same structure when its ground plane is segmented.
71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗