High efficiency magnetic bearings

Research activities concerning high efficiency permanent magnet plus electromagnet (PM/EM) pancake magnetic bearings at the University of Maryland are reported. A description of the construction and working of the magnetic bearing is provided. Next, parameters needed to describe the bearing are explained. Then, methods developed for the design and testing of magnetic bearings are summarized. Finally, a new magnetic bearing which allows active torque control in the off axes directions is discussed

Neural network controller development for a magnetically suspended flywheel energy storage system

A neural network controller has been developed to accommodate disturbances and nonlinearities and improve the robustness of a magnetically suspended flywheel energy storage system. The controller is trained using the back propagation-through-time technique incorporated with a time-averaging scheme. The resulting nonlinear neural network controller improves system performance by adapting flywheel stiffness and damping based on operating speed. In addition, a hybrid multi-layered neural network controller is developed off-line which is capable of improving system performance even further. All of the research presented in this paper was implemented via a magnetic bearing computer simulation. However, careful attention was paid to developing a practical methodology which will make future application to the actual bearing system fairly straightforward

METHODS FOR PREDICTING THE REMAINING LIFE OF ELECTRONIC ASSEMBLIES WITH CARBON NANOTUBES AND AN OPTICAL TRANSDUCTION TECHNIQUE

ABSTRACT Life consumption monitoring is a method of quantifying the degradation of a system by monitoring the life cycle environment. With current research demonstrating the value of nanotubes as sensors, they may prove to be an inexpensive, compact, and reliable means to monitor not only system environments, but also physical signs of degradation. Life consumption monitoring of electronic assemblies can be cost-effectively done using optical strain measurement techniques. In this study, current output from an optical sensor can be used to interpret combined temperature and vibration histories. This may be accomplished by passing monofrequency light through optical fibers in a peripheral arrangement on a dummy chip. Any deviation from the null condition results in misalignment of the fibers, and hence reduction in intensity and current output. With appropriate failure data at different stress levels, it is possible to determine damage and estimate the remaining life. The key challenges are to determine whether such an optical health monitoring scheme can be sufficiently accurate and robust, and whether the results can be applied to a variety of packages at any location on a circuit assembly

Davinder K. Anand - Research and Related Activities 1965-2020

Research Documents and Books published by Davinder K. Anand, Professor Emeritus of the Mechanical Engineering Department, University of Maryland, College Park.Over the past fifty-five years, I have worked on problems related to dye dilution for the analysis of cardiac output, heat pipes as a high conductivity device, satellite attitude control, solar energy usage and design of systems for building heating and cooling applications, design and control of magnetically suspended flywheels for energy storage, design of magnetic bearings, magnetic spindles for high speed machining, manufacturing systems, system simulation and virtual environments as a design tool for a group of various mechanical components, and a number of unique problems of interest to me such as STEM education and R&D funding policy of the Navy

CLOURE: Clustal Output Reformatter, a program for reformatting ClustalX/ClustalW outputs for SNP analysis and molecular systematics

We describe a program (and a website) to reformat the ClustalX/ClustalW outputs to a format that is widely used in the presentation of sequence alignment data in SNP analysis and molecular systematic studies. This program, CLOURE, CLustal OUtput REformatter, takes the multiple sequence alignment file (nucleic acid or protein) generated from Clustal as input files. The CLOURE-D format presents the Clustal alignment in a format that highlights only the different nucleotides/residues relative to the first query sequence. The program has been written in Visual Basic and will run on a Windows platform. The downloadable program, as well as a web-based server which has also been developed, can be accessed at http://imtech.res.in/~anand/cloure.html

History of the Mechanical Engineering Department at the University of Maryland, College Park: 1894 to 2018

Research and education activities of Mechanical Engineering at the University of Maryland, College Park from 1894 to 2018.Research and education activities of Mechanical Engineering at the University of Maryland, College Park from 1894 to 2018. Significant growth in the student body, research depth and breadth, and the size and quality of faculty is covered. The Department grew from two faculty members in 1945 to 50 faculty members in 2018, teaching and doing state of the art research in all facets of Mechanical Engineering

The “Engineering for Social Change” Course: A CECD Experiment

The course entitled Engineering for Social Change was offered as an experiment to study the unintended consequences of technology at the intersection of engineering, philanthropy, and social change. The pilot program, in collaboration with the School of Public Policy, was started in the spring semester of 2015 and was concluded with the final offering in the Fall of 2022. The experiment was conducted under the aegis of the Mechanical Engineering Department but almost entirely funded by CECD and The Neilom Foundation. The student body consisted of undergraduate engineers from the entire college, computer science students, and some foreign exchange students. The offering was consistent with the vision of the Center for Engineering Concepts Development (CECD), which is to serve as a platform for experimenting with new ideas in engineering education, future technologies, research, and the impact of engineering on society. The Engineering for Social Change course was a very successful experiment as evidenced by the overwhelmingly positive student feedback. The key concept of unintended consequences from technological progress opened an entirely new and challenging thought process. The many expressions of support, engagement, and excitement makes the point more clearly than what we can say

Error Minimization in Numerical Controlled Machining.

Material removal rate in numerical controlled machining, especially in thin rib machining, is limited by the onset of tool path error and chatter. In this paper we propose that it is possible to increase the metal removal rate while maintaining the required dimensional accuracy and surface finish by modeling the cutting process as stochastic. With this improved modeling it will be possible to predict the characteristics of finished surface more accurately. A methodology to identify the system parameters and the design of an optimal controller to minimize stochastic tool path error in thin rib machining is presented

Magnetic Bearing Spindles for Enhancing Tool Path Accuracy.

Thin rib machining of electronic components or airframe structures can beneflt from high speed machining for burr free cuttlag, improved surface quality and increased metal removal rate. It is suggested that the use of a magnetic bearing spindle can not only successfully provide the beneflts of high speed machining but, more importantly, minimize tool path errors. In this paper the various sources of tool path errors are discussed as functions of machine tool positioning errors and cutting force errors which are characterized as static, dynamic and stochastic. The operation of high speed magnetic bearing spindles is described and a control scheme whereby the spindle may be translated and tilted for minimizing tool path errors is discussed. This overall research activity is a cooperative effort between The University of Maryland, Cincinnati Milacron, and The National Bureau of Standards