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Engineering the environmentally sound warship for the twenty-first century

NAVAL ENGINEERS JOURNAL 1999年第3期111卷 189-217页

作者： Markle, SP Gill, SE McGraw, PS Udr. Stephen P. Markle USN is a career Engineering Duty officer assigned to Naval Sea Systems Command Arlington Virginia where he is Deputy Directs Environmental Programs Division (SEA 03L1 B). He is responsible fm program management activities associated with all ahat environmental protection equipment design and selection of environmental protection equipment and systems fm future surface ship designs (DD 21 CVN 7Z CW LPD 17) and serves on several teams designed to promote Nay wide awarmss of environmental protection requirements and Nay programs to meet these challenges. He is a 1993 graduate of the Naval Construction and Engineering Program at the Massachusetts Institute of Technology where he received a naval engineers degree and master of science in mechanical engineering. His interest in environmental issues predates his undergraduate studies at Syracuse Universityl State University of New Ymk College of Environmental Science and Fmestry where he received a bachelm of science degree in fmest engineering from the School of Environmental and Resource Engineering. LCdx Markle has qualified as a Surface Warfare Officer and in submarines through the Engineering Duty Dolphin Program he is a member of the Acquisition Professional Community and a graduate of the Defense Systems Management College Advanced Program Managers Course. He is a professional engineer registered in the State of New York and is a member ofthe American Society of Naval Engineers National Society of Professional Engineers American Society for Testing and Materials Society of Naval Architects and Marine Engineers and Society of Automotive Engineers. Peter 5. McGraw is current the Acting Branch Head ofthe Solid Waste Management Branch (Code 634) of the Environmental Quality Dwrtment of the Naval Surfice Warfare Centel: Carderock Division. As such he is responsible for among other things: the Shipboard Advanced Incinerator RDT&E Program the Submarine Plastic Waste RDT&E Program Solid Waste Processing Equipment Design Acquisitio

The past twenty-five years has been marked by the introduction ed marine environmental regulations that have had a profound effect on how ships are designed, built and operated. Ships being designed and built today must accommodate not only current regulations but anticipate those enacted over their thirty to fifty year life cycles. U.S. Chief of Naval Operations, Office of Environmental, Safety and Health (CNO N45) has articulated a vision for the Environmentally Sound Warship of the Twenty-first Century. This vision incorporates the "Sense of Congress" for a naval ship designed to operate in full compliance with environmental regulations worldwide. The task of the Navy engineering team is to translate this vision into reality;a ship capable of prevailing in time of war and able to conduct operations in all areas of the globe, unencumbered by special procedures for environmental compliance. The keys to this warship design are the early integration of environmentally sound principles, materials, and processes into the ship acquisition process;minimization of both hazardous materials and generation of post shipboard consumer waste during operation;adaptation of integrated systems to reduce the volume of wastes and enhance processing efficiency;reduced manpower requirements;and crew indoctrination in environmental protection.

关键词： Ships Environmental regulations Engineering ARTICULATED Navy environmental security

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Hardware Architecture for Particle Swarm Optimization Using Floating-Point Arithmetic

Hardware Architecture for Particle Swarm Optimization Using ...

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International Conference on Intelligent systems Design and Applications (ISDA)

作者： Daniel M. Muñoz Arboleda Carlos H. Llanos Leandro dos_S. Coelho Mauricio Ayala-Rincón Department of Mechanical Engineering University of Brasilia Brasília Brazil Industrial and Systems Engineering Graduate Program Pontificial Catholic University of Paraná Curitiba Brazil Departments of Computer Science and Mathematics University of Brasilia Brasília Brazil

High computational cost for solving large engineering optimization problems point out the design of parallel optimization algorithms. Population based optimization algorithms provide parallel capabilities that can be explored by their implementations done directly in hardware. This paper presents a hardware implementation of particle swarm optimization algorithms using an efficient floating-point arithmetic which performs the computations with high precision. All the architectures are parameterizable by bit-width, allowing the designer to choose the suitable format according to the requirements of the optimization problem. Synthesis and simulation results demonstrate that the proposed architecture achieves satisfactory results obtaining a better performance in therms of elapsed time than conventional software implementations.

关键词： Hardware Particle swarm optimization Floating-point arithmetic Computer architecture Design optimization Computational efficiency Design engineering Algorithm design and analysis High performance computing Computational modeling

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Help on SOS [Ask the Experts]

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IEEE Control systems 2010年第4期30卷 18-23页

作者： Ufuk Topcu Andy Packard Peter Seiler Gary Balas Mechanical Engineering Department University of California Berkeley USA California Institute of Technology USA Aerospace Engineering and Mechanics Control Science and Dynamical Systems program University of Minnesota USA Aerospace Engineering and Mechanics Department University of Minnesota USA Research and Development Honeywell International Inc. USA

In this issue of IEEE Control systems Magazine, Andy Packard and friends respond to a query on determining the region of attraction using sum-of-squares methods.

关键词： Polynomials Symmetric matrices Convergence Yield estimation Control theory Matrix decomposition

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Modeling and simulation of the microalgae derived hydrogen process in compact photobioreactors

Modeling and simulation of the microalgae derived hydrogen p...

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IEEE Conference on Technologies for Sustainability

作者： J. V. C. Vargas D. A. Mitchell A. B. Mariano D. O. Correa J. C. Ordonez Graduate Program in Engineering and Materials Science PIPE and Sustainable Energy Research and Development Center NPDEAS Federal University of Parana Department of Mechanical Engineering Energy and Sustainability Center and Center for Advanced Power Systems Florida State University FSU

ISBN: (纸本)9781467346290

A general transient mathematical model for managing microalgae derived hydrogen production, with temperature dependence of the cultivation medium is developed. For that, the simplified physical model combines principles of classical thermodynamics, mass, species and heat transfer, resulting in a system of differential equations which are discretized in space using a three-dimensional cell-centered finite volume scheme. A Michaelis-Menten type expression is proposed for modeling the rate of H_2 production with dependence on O_2 inhibition. Tridimensional simulations are performed in order to determine the mass fractions distributions inside a compact photobioreactor (PBR), under different operating conditions. A relatively coarse mesh was used (6048 volume elements) to obtain converged results for a large compact PBR computational domain (5m×2m×8m). The largest computational time required for obtaining results was 560 s, i.e., less than 10 min. The numerical results for microalgal growth are validated by direct comparison to experimental measurements. Hydrogen production simulations are conducted to demonstrate PBR intermittent operation (aerobic and anaerobic stages) feasibility and adequate species evolution trends in an indirect biophotolysis approach. Therefore, after experimental validation for a particular H_2 production system, it is reasonable to state that the model could be used as an efficient tool for PBR systems thermal design, control and optimization for maximum H_2 production.

关键词： Chlamydomonas reinhardtii Scenedesmus sp. Photobioreactor architecture Early stage design tool

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Steering Control for Autonomous Vehicles Using PID Control with Gradient Descent Tuning and Behavioral Cloning

Steering Control for Autonomous Vehicles Using PID Control w...

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Novel Intelligent and Leading Emerging sciences Conference (NILES)

作者： Mohamed Esmail Abed Mo'men Aly Hossam Hassan Ammar Raafat Shalaby Mechanical Engineering Program School of Engineering and applied sciences Nile University Shaikh Zayed City Egypt Smart Engineering Systems Research Center (SESC) School of Engineering and Applied Science Nile University Shaikh Zayed City Egypt

ISBN: (数字)9781728182261

ISBN: (纸本)9781728182278

In this paper we implement and evaluate two ways of controlling the steering angle of an autonomous vehicle, PID control with manual tuning followed by gradient descent algorithm tuning-which is able to enhance the performance through self-adjusting the controller parameters-and using supervised machine learning through the end-to-end deep learning for self-driving car which implement Convolutional Neural Network (CNN) to predict the steering angle for a given instance of a track. The verification testing went through two phases: software simulation using python for first run testing and C++ for simulation followed by track testing with a vehicle prototype. The proposed PID steering control system exhibits more stable steering commands-less oscillations-which makes it better than CNN Behavioral cloning control model. However, CNN Behavioral Cloning model may show better results after many several hours of training.

关键词： Automobiles Tuning Training Cameras Testing Mathematical model Wheels

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Magnetoelastic coupling driven magnon gap in a honeycomb antiferromagnet

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Physical Review B 2024年第10期110卷 104419页

作者： Jeongheon Choe Andrey Baydin Gaihua Ye Bowen Ma Cynthia Nnokwe Martin Rodriguez-Vega David Lujan Swati Chaudhary Fuyang Tay Jiaming He Hiroyuki Nojiri Jianshi Zhou Gregory A. Fiete Junichiro Kono Rui He Xiaoqin Li Department of Physics Center of Complex Quantum Systems Center for Dynamics and Control of Materials Department of Electrical and Computer Engineering Smalley–Curl Institute Department of Physics Applied Physics Graduate Program Smalley–Curl Institute Department of Mechanical Engineering Institute for Materials Research Department of Physics and Astronomy Department of Materials Science and NanoEngineering

Cobalt titanate, CoTiO3, is a honeycomb antiferromagnet recently confirmed experimentally to host Dirac magnons, topological spin-orbit excitons, and chiral phonons. Here, we investigate a magnon gap at the zone center which calls for a refined spin Hamiltonian. We propose a microscopic model for the magnon gap and attribute it to a lattice-distortion (phonon)-induced higher-order spin interaction. Strong magnetoelastic coupling in CoTiO3 is also evident in Raman spectra, in which the magnetic order exerts a stronger influence on phonons corresponding to in-plane ionic motions than those with out-of-plane motions. We further examine the evolution of the zone-center magnons in a high magnetic field up to 18.5 T via THz absorption spectroscopy measurements. Based on this field dependence, we propose a spin Hamiltonian that not only agrees with magnon dispersion measured by inelastic neutron scattering but also includes fewer exchange constants and a realistic anisotropy term. Our work highlights the broad implications of magnetoelastic coupling in the study of topologically protected bosonic excitations.

关键词： Magnetism Magnons Topological materials Raman spectroscopy Terahertz spectroscopy

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CVIT: CONTINUOUS VISION TRANSFORMER FOR OPERATOR LEARNING

arXiv

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arXiv 2024年

作者： Wang, Sifan Seidman, Jacob H. Sankaran, Shyam Wang, Hanwen Pappas, George J. Perdikaris, Paris Institution for Foundation of Data Science Yale University United States Graduate Program in Applied Mathematics and Computational Science University of Pennsylvania United States Department of Mechanical Engineering and Applied Mechanics University of Pennsylvania United States Department of Electrical and Systems Engineering University of Pennsylvania United States

Operator learning, which aims to approximate maps between infinite-dimensional function spaces, is an important area in scientific machine learning with applications across various physical domains. Here we introduce the Continuous Vision Transformer (CViT), a novel neural operator architecture that leverages advances in computer vision to address challenges in learning complex physical systems. CViT combines a vision transformer encoder, a novel grid-based coordinate embedding, and a query-wise cross-attention mechanism to effectively capture multi-scale dependencies. This design allows for flexible output representations and consistent evaluation at arbitrary resolutions. We demonstrate CViT’s effectiveness across a diverse range of partial differential equation (PDE) systems, including fluid dynamics, climate modeling, and reaction-diffusion processes. Our comprehensive experiments show that CViT achieves state-of-the-art performance on multiple benchmarks, often surpassing larger foundation models, even without extensive pretraining and roll-out fine-tuning. Taken together, CViT exhibits robust handling of discontinuous solutions, multi-scale features, and intricate spatio-temporal dynamics. Our contributions can be viewed as a significant step towards adapting advanced computer vision architectures for building more flexible and accurate machine learning models in the physical sciences. All data and code are publicly available at https://***/PredictiveIntelligenceLab/cvit. © 2024, CC BY-NC-SA.

关键词： Computer vision

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Gaussian Process Port-Hamiltonian systems: Bayesian Learning with Physics Prior

Gaussian Process Port-Hamiltonian Systems: Bayesian Learning...

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IEEE Conference on Decision and Control

作者： Thomas Beckers Jacob Seidman Paris Perdikaris George J. Pappas Department of Electrical and Systems Engineering University of Pennsylvania Philadelphia PA USA graduate program in Applied Mathematics and Computational Science University of Pennsylvania Philadelphia PA USA Department of Mechanical Engineering and Applied Mechanics University of Pennsylvania Philadelphia PA USA

ISBN: (数字)9781665467612

ISBN: (纸本)9781665467629

Data-driven approaches achieve remarkable results for the modeling of complex dynamics based on collected data. However, these models often neglect basic physical principles which determine the behavior of any real-world system. This omission is unfavorable in two ways: The models are not as data-efficient as they could be by incorporating physical prior knowledge, and the model itself might not be physically correct. We propose Gaussian Process Port-Hamiltonian systems (GPPHS) as a physics-informed Bayesian learning approach with uncertainty quantification. The Bayesian nature of GP-PHS uses collected data to form a distribution over all possible Hamiltonians instead of a single point estimate. Due to the underlying physics model, a GP-PHS generates passive systems with respect to designated inputs and outputs. Further, the proposed approach preserves the compositional nature of Port-Hamiltonian systems.

关键词： Uncertainty Gaussian processes Probabilistic logic Data models Bayes methods Behavioral sciences Kernel

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Effect of Overload and Underload on Subsequent Deformation Behavior during Cyclic Deformation

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Zairyo/Journal of the Society of Materials science, Japan 2022年第2期71卷 159-166页

作者： Kondou, Ryouji Yama, Katsunari Energy and Environmental Program School of Engineering Faculty of Engineering University of the Ryukyus Nishihara-cho Nakagami-gun Okinawa903-0213 Japan Department of Mechanical Systems Engineering Graduate School of Engineering and Science University of the Ryukyus Nishihara-cho Nakagami-gun Okinawa903-0213 Japan

A multi-scale analysis of elasto-plastic deformation and dislocation movement and accumulation of tricrystalline models during cyclic deformation was performed. The accumulation of dislocations in geometrically necessary dislocations (GNDs) and statistically stored dislocations (SSDs) was investigated in detail. Experimental observations have shown that fatigue life and fatigue crack propagation are also deteriorated when the material is subjected to overload or underload. However, in the microscopic and mesoscopic regions, where the effects of the crack tip shape change are not related to the size of the crack tip, a different phenomenon is essentially occurring. In this paper, the effects of overload and underload are investigated using a simple model without a crack. From the analysis results, it was found that the dislocation structure generated in the material subjected to overload or underload affects the subsequent deformation behavior. However, even though the absolute values are the same, the effects of overloading and underloading on the subsequent deformation are different, and underloading increases the non-uniformity of the subsequent deformation, which is on the dangerous side, while overloading decreases with increasing the number of repetitions. ©2022 The Society of Materials science, Japan

关键词： Crack tips

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Towards faster, smoother, and more compact fuzzy approximation, with an application to non-destructive evaluation of space shuttle's structural integrity

Towards faster, smoother, and more compact fuzzy approximati...

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Conference of the North American Fuzzy Information Processing Society - NAFIPS

作者： Yeung Yam R. Osegueda V. Kreinovich Department of Mechanical & Automation Engineering Chinese University of Hong Kong New Territories Hong Kong China Future Aerospace Science and Technology Program (FAST) Center for Structural Integrity of Aerospace Systems University of Technology El Paso TX USA

It is known that fuzzy systems are universal approximators, i.e., any input-output system can be approximated, within any given accuracy, by a system described by fuzzy rules. Fuzzy rules work well in many practical applications. However, in some applications, the existing fuzzy rule approximation techniques are not sufficient. First, in many practical problems (e.g., in many control applications), derivatives of the approximated function are very important, and so, we want not only the approximating function to be close to the approximated one, but we also want their derivatives do be close; however, standard fuzzy approximation techniques do not guarantee the accuracy of approximating a derivative. Second, to get the desired approximation accuracy, we sometimes need unrealistically many rules. We show how both problems can be solved.

关键词： Extrapolation Fuzzy control Automatic control Fuzzy systems Nondestructive testing Space technology Aerospace engineering Image reconstruction Stress Space shuttles

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