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Control of fluid-containing rotating rigid bodies
\"This book is devoted to the study of the dynamics of rotating bodies with cavities containing liquid. Two basic classes of motion are analyzed: rotation and libration. Cases of complete and partial filling of cavities with ideal liquid and complete filling with viscous liquid are treated. A method is presented for obtaining relations between angular velocities perpendicular to main rotation and external force momentums, treated as control. This work will be of interest to professionals and researchers at universities and laboratories specializing in problems of control for hybrid systems and aerospace/mechanical engineering, as well as to under-/postgraduates with this specialization\"-- Provided by publisher.
Book
Aluminum Goalpost Nano-mechanical Devices at Low Temperatures
Mechanical objects have been widely used at low temperatures for decades, for various applications; from quantum fluids sensing with vibrating wires or tuning forks, to torsional oscillators for the study of mechanical properties of glasses, and finally micro and nano-mechanical objects with the advent of clean room technologies. These small structures opened up new possibilities to experimentalists, thanks to their small size. We report on the characterization of purely metallic goalpost nano-mechanical structures, which are employed today for both quantum fluids studies (especially quantum turbulence in
4
He,
3
He) and intrinsic friction studies (Two-level-systems unraveling). Extending existing literature, we demonstrate the analytic modeling of the resonances, in good agreement with numerical simulations, for both first
and second
mechanical modes. Especially, the impact
of the curvature
of the whole structure (and therefore, in-built surface stress) is analyzed, together with nonlinear properties. We demonstrate that these are of geometrical origin and
device-dependent
. Motion and forces are expressed in meters and Newtons experienced at the level of the goalpost’s paddle, for
any
magnitude or curvature, which is of particular importance for quantum fluids and solids studies.
Journal Article
Optimal failure mode-based preventive maintenance scheduling for a complex mechanical device
This paper addresses the issue of PM scheduling for a complex mechanical with different failure modes. Unlike conventional studies which only consider a single failure mode without prior health information, our work jointly optimizes the failure time estimation and maintenance scheduling for mechanical systems under different failure modes. The proposed approach considers the failure modes which are fatal to the system function and performance. Firstly, the fatal failure modes are identified and divided into two types: the degraded and functional failure modes. The former indicates the one that has an explicit detectable degradation process till the predefined failure threshold is exceeded, while the latter indicates the failure modes that occur suddenly. For both types of failure modes, approaches of failure time estimation are presented to provide the actual health status information for maintenance scheduling. Afterwards, the maintenance scheduling problem is formulated on the estimated failure time distributions of the multiple failure modes. The integer-constrained genetic algorithm (GA) is adopted to optimize the preventive maintenance scheduling by minimizing the life-cycle cost rate. The optimal PM scheduling is derived based on the following: (1) when to perform the intermediate and major maintenance and (2) which failure mode should be maintained at an intermediate maintenance epoch. Finally, the performance of the proposed approach is validated through a real case of the ram subsystem of a boring machine.
Journal Article
Energy consumption behavior analysis and experimental investigation of a novel technique for energy-efficient operation of submersible pumping system used in Barind Tract of Bangladesh
In this present study, energy consumption behavior and performance of the submersible pumping system running at different sites in the Barind Tract of Bangladesh have been investigated and compared with those of the lab test results of new pumps. It is found that the efficiency of the running pumps is 20–40% lower than that of laboratory efficiency. The total operating head of the submersible pump includes a parameter known as “drawdown” which has a significant effect on its performance. The drawdown characteristics of a 15 HP submersible pump have been studied in the laboratory by varying bore well diameter. It is observed that the amount of drawdown, as well as efficiency, decreases significantly with increasing bore well diameter. This work provides new ideas by incorporating three different mechanical devices (plane, bowl, and propeller) attached to the delivery pipe near the pump to achieve higher efficiency as well as lower energy consumption and compared while using no device. It is possible to obtain 55% efficiency by using a bowl type of a mechanical device in an 8-in bore well that is 5% higher while using no device. On the other hand, there is an opportunity to attain 57% efficiency by using all three devices (plane, bowl, and propeller) at a time in 8-in bore well that is 7% higher while using no attachment. By integrating the mechanical devices in the Talaimari pumping site of Rajshahi Water Supply and Sewerage Authority (RWASA), the annual cost and energy savings will be 61,964.52 BDT and 8074.56 kWh, respectively.
Graphical Abstract
Journal Article
Low-Cycle Fatigue Testing of Ni Nanowires Based on a Micro-Mechanical Device
Despite extensive research on the mechanical properties of one-dimensional (1-D) nanomaterials such as nanowires and nanotubes in the past two decades, experimental data on the fatigue behavior of 1-D building blocks are still very limited. Here, we demonstrate the first quantitative in situ tensile fatigue testing of individual nanowires inside a high-resolution scanning electron microscope (SEM), based on the nanoindenter-assisted “push-to-pull” dynamic tensile straining mechanism. With the robust micro-mechanical devices and independent quantitative nanoindenter for actuation and force sensing, we achieved both stress- and strain-controlled cyclic tensile loading on nanowire samples with variable loading frequencies up to 10 Hz, and demonstrated the low-cycle fatigue behavior of pristine single crystalline nickel (Ni) nanowires.
Journal Article
Programmable mechanical devices through magnetically tunable bistable elements
Mechanical instabilities, especially in the form of bistable and multistable mechanisms, have recently garnered a lot of interest as a mode of improving the capabilities and increasing the functionalities of soft robots, structures, and soft mechanical systems in general. Although bistable mechanisms have shown high tunability through the variation of their material and design variables, they lack the option of modifying their attributes dynamically during operation. Here, we propose a facile approach to overcome this limitation by dispersing magnetically active microparticles throughout the structure of bistable elements and using an external magnetic field to tune their responses. We experimentally demonstrate and numerically verify the predictable and deterministic control of the response of different types of bistable elements under varying magnetic fields. Additionally, we show how this approach can be used to induce bistability in intrinsically monostable structures simply by placing them in a controlled magnetic field. Furthermore, we show the application of this strategy in precisely controlling the features (e.g., velocity and direction) of transition waves propagating in a multistable lattice created by cascading a chain of individual bistable elements. Moreover, we can implement active elements like a transistor (gate controlled by magnetic fields) or magnetically reconfigurable functional elements like binary logic gates for processing mechanical signals. This strategy serves to provide programming and tuning capabilities required to allow more extensive utilization of mechanical instabilities in soft systems with potential functions such as soft robotic locomotion, sensing and triggering elements, mechanical computation, and reconfigurable devices.
Journal Article
Quantum state preparation and tomography of entangled mechanical resonators
Precisely engineered mechanical oscillators keep time, filter signals and sense motion, making them an indispensable part of the technological landscape of today. These unique capabilities motivate bringing mechanical devices into the quantum domain by interfacing them with engineered quantum circuits. Proposals to combine microwave-frequency mechanical resonators with superconducting devices suggest the possibility of powerful quantum acoustic processors
1
–
3
. Meanwhile, experiments in several mechanical systems have demonstrated quantum state control and readout
4
,
5
, phonon number resolution
6
,
7
and phonon-mediated qubit–qubit interactions
8
,
9
. At present, these acoustic platforms lack processors capable of controlling the quantum states of several mechanical oscillators with a single qubit and the rapid quantum non-demolition measurements of mechanical states needed for error correction. Here we use a superconducting qubit to control and read out the quantum state of a pair of nanomechanical resonators. Our device is capable of fast qubit–mechanics swap operations, which we use to deterministically manipulate the mechanical states. By placing the qubit into the strong dispersive regime with both mechanical resonators simultaneously, we determine the phonon number distributions of the resonators by means of Ramsey measurements. Finally, we present quantum tomography of the prepared nonclassical and entangled mechanical states. Our result represents a concrete step towards feedback-based operation of a quantum acoustic processor.
Piezoelectric coupling of a single superconducting qubit to two phononic crystal nanoresonators results in an integrated device that is able to control and read out the quantum state of the two mechanical resonators.
Journal Article
Failure time prediction for mechanical device based on the degradation sequence
Mechanical devices are playing a crucial role in modern industry. With the ever-growing demands of multiple function and high performance, the unpredicted failures of mechanical device might greatly increase maintenance cost during its lifetime. As a key state indicator of mechanical device, the degradation of some important performance provides substantial information for failure prognosis. More and more attention has been paid to the degradation-based failure time prediction. However, even mechanical devices of the same type might show greatly diverse degradation processes under different working environments. It is still a challenge to identify global degradation pattern and then predict the failure time of a specific mechanical device based on its degradation sequence. This paper proposes a novel approach for failure time prediction with the degradation sequence of mechanical device. The proposed approach combines the exponential regression and parametric empirical Bayesian (PEB) technology. Firstly, exponential regression is adopted to represent the local degradation pattern and then local failure time observations can be computed. Secondly, according to the rule that local failure time observations manifest, appropriate prior assumption is made and the posterior distribution is estimated by PEB technology. Herein, two prior assumptions are considered, including the exchangeable PEB and linear PEB case. The global failure time distribution can be predicted with the estimated prior and posterior distribution. Finally, three case studies are implemented to validate the proposed approach, including the simulation case, crack case and precision case of machine tool.
Journal Article
Very-large-scale integrated quantum graph photonics
Graphs have provided an expressive mathematical tool to model quantum-mechanical devices and systems. In particular, it has been recently discovered that graph theory can be used to describe and design quantum components, devices, setups and systems, based on the two-dimensional lattice of parametric nonlinear optical crystals and linear optical circuits, different to the standard quantum photonic framework. Realizing such graph-theoretical quantum photonic hardware, however, remains extremely challenging experimentally using conventional technologies. Here we demonstrate a graph-theoretical programmable quantum photonic device in very-large-scale integrated nanophotonic circuits. The device monolithically integrates about 2,500 components, constructing a synthetic lattice of nonlinear photon-pair waveguide sources and linear optical waveguide circuits, and it is fabricated on an eight-inch silicon-on-insulator wafer by complementary metal–oxide–semiconductor processes. We reconfigure the quantum device to realize and process complex-weighted graphs with different topologies and to implement different tasks associated with the perfect matching property of graphs. As two non-trivial examples, we show the generation of genuine multipartite multidimensional quantum entanglement with different entanglement structures, and the measurement of probability distributions proportional to the modulus-squared hafnian (permanent) of the graph’s adjacency matrices. This work realizes a prototype of graph-theoretical quantum photonic devices manufactured by very-large-scale integration technologies, featuring arbitrary programmability, high architectural modularity and massive manufacturing scalability.A graph-theoretical programmable quantum photonic device composed of about 2,500 components is fabricated on a silicon substrate within a 12 mm × 15 mm footprint. It shows the generation, manipulation and certification of genuine multiphoton multidimensional entanglement, as well as the implementations of scattershot and Gaussian boson sampling.
Journal Article
Digital synthesis of free-form multimaterial structures for realization of arbitrary programmed mechanical responses
Programming structures to realize any prescribed mechanical response under large deformation is highly desired for various functionalities, such as actuation and energy trapping. Yet, the use of a single material phase and heuristically developed structural patterns leads to restricted design space and potential failure to achieve specific target behaviors. Here, through a free-form inverse design approach, multiple hyperelastic materials with distinct properties are optimally synthesized into composite structures to precisely achieve arbitrary and extreme prescribed responses under large deformations. The digitally synthesized structures exhibit organic shapes and motions with irregular distributions of material phases. Within the structures, different materials play distinct roles yet seamlessly collaborate through sophisticated deformation mechanisms to produce the target behaviors, some of which are unachievable by a single material. While complex in geometry and material heterogeneity, the discovered structures are effectively manufactured via multimaterial fabrication with different polydimethylsiloxane (PDMS) elastomers with distinct behaviors and their highly nonlinear responses are physically and accurately realized in experiments. To enhance programmability, the synthesized structures are heteroassembled into architectures that exhibit highly complex yet navigable responses. The proposed synthesis, multimaterial fabrication, and heteroassembly strategy can be utilized to design function-oriented and situation-specific mechanical devices for a wide range of applications.
Journal Article