Engineering Commons^™

In-Line Photoresist Thickness Monitor, Richard N. Savage, Tom W. Batchelder, Kenneth M. Sautter, Gary H. Memovich

Materials Engineering

An in-line photoresist thickness measuring device wherein a plurality of projection optical fibers are disposed over a wafer processing track for illuminating portions of a wafer as the wafer proceeds along the track. The light scattered back from each illuminated portion is detected by a corresponding plurality of pickup optical fibers and communicated to an optical fiber multiplexer. The multiplexer sequentially selects the optical signal from each pickup optical fiber and communicates the light from the selected pickup optical fiber to a spectrometer. The spectrometer simultaneously diffuses the scattered light into a plurality of light bands, each light band having …

Advanced Space Design Program, William W. Durgin, Francis C. Lutz

Office of the Provost Scholarship

Worcester Polytechnic Institute's Advanced Space Design (ASD) Program provides project-based design experiences that combine a highly motivating, need-to-know experience with an integrative capstone design that draws on the know-how of practitioners in the profession. Mechanical engineering students work with their counterparts in electrical, chemical, and civil engineering to develop integrated packages of experiments to be conducted in the micro-gravity environment of space.

Relative And Absolute Timing Jitter In Actively Mode-Locked Semiconductor Lasers, Dennis J. Derickson, A. Mar, J. E. Bowers

Electrical Engineering

No abstract provided.

Real-Time, In-Situ Measurement Of Film Thickness And Uniformity During Plasma Ashing Of Photoresist, Richard N. Savage, Horace Simmons, John T. Davies, Thomas Metz

Materials Engineering

This paper will discuss the performance of equipment which monitors and so controls photoresist thickness and uniformity during plasma ashing without interfering with the process. Practical monitoring of a subtractive process of this type is significantly more complex than monitoring deposition processes. An initial absolute thickness measurement is needed. In addition the device must view the layer through a luminous medium and cannot rely on simple optical interference fringe counting. The equipment is self-calibrating and sensitive to layers dnm thick. An application to partial plasma resist ashing in high uniformity equipment will be described. Application to other films (e. g. …

Optical Switch, Richard N. Savage

Materials Engineering

An optical switch for transmitting light between a first location and a selected one of a plurality of second locations. The switch includes a mirror having a concave, reflective surface and an axis. The switch also includes a plurality of fiber optic cables, one of which is disposed at the first location and the remainder of which are disposed at the second locations, each cable having a light transmission face at their respective locations. The light transmission face at the first location is substantially parallel to the focal plane of the mirror. The light transmission face at each of the …

Spray Drift Reduction With Shrouded Boom Sprayers, Ronald J. Fehringer, Richard Cavaletto

BioResource and Agricultural Engineering

Downwind drift was measured from a standard boom sprayer and a shrouded boom sprayer. Using 8002 flat fan nozzles, the hooded sprayer provided a 180 to 275% reduction in drift. The effectiveness of the shroud is dependent upon the spray droplet spectrum.

Synergy Of Artificial Neural Networks And Knowledge-Based Expert Systems For Intelligent Fms Scheduling, Luis Carlos Rabelo, Sema E. Alptekin, Ali S. Kiran

Industrial and Manufacturing Engineering

In this paper we describe a hybrid architecture that integrates artificial neural networks and knowledge-based expert systems to generate solutions for the real time scheduling of flexible manufacturing systems. The artificial neural networks perform pattern recognition and, due to their inherent characteristics, support the implementation of automated knowledge acquisition and refinement schemes through a feedback mechanism. The artificial neural network structures enable the system to recognize patterns in the tasks to be solved in order to select the best scheduling rule according to different demands. The knowledge-based expert systems are the higher order elements which drive the inference strategy and …

A Suggested Model Program For Cim Education, Sema E. Alptekin

Industrial and Manufacturing Engineering

No abstract provided.

Adaptive Scheduling And Control Using Artificial Neural Networks And Expert Systems For A Hierarchical/Distributed Fms Architecture, Luis Carlos Rabelo, Sema E. Alptekin

Industrial and Manufacturing Engineering

An adaptive expert scheduler was developed that learns by itself and adapts to the dynamic FMS environment. This hybrid system uses a symbiotic architecture composed of expert systems (ESs) and artificial neural networks (ANNs) and provides a learning scheme guided by past experience. The artificial neural networks recognize patterns in the tasks to be solved in order to select the best scheduling rule according to different criteria. The expert systems, on the other hand, drive the inference strategy and interpret the constraints and restrictions imposed by the upper levels of the control hierarchy of the flexible manufacturing system. The level …

Irrigation District Canal Automation - Cardd, Charles M. Burt

BioResource and Agricultural Engineering

The first rule regarding irrigation district canal automation is that there is no single "best" method of automations. The locations of buffer reservoirs, the ability to allow water to spill at the ends of canals, the storage capacity of canal pools, and the topography will also play key roles in deciding if automation is desirable, and what type of automation should be used. These typical engineering considerations must also be coupled with recognition of the limitations and abilities of irrigation district staff regarding maintenance and trouble shooting of sophisticated controls.

Architecture For A Human-Robot Symbiotic System, Fred W. Depiero, Wayne W. Manges, Reid L. Kress, Mike R. Kedl, William R. Hamel

Electrical Engineering

This paper describes a human-robot symbiont that is under development at Oak Ridge National Laboratory. An overview of the symbiotic system is described that motivates the architecture that has been developed. The architecture is a hierarchical structure that consists of several expert systems which reside above a robot control interface. This interface allows the manipulator to be operated in both a teleoperated and autonomous mode. All these processes coexist with the lowest level of the hierarchy, which is a numerically intensive control algorithm. The architecture is implemented on five processors in a coarsely parallel system.

A Transient Electromagnetic Flowmeter And Calibration Facility, Paul J. Lefebvre, William W. Durgin

Office of the Provost Scholarship

An electromagnetic flowmeter was developed to measure transient flows at a data rate of 60 Hz. The approach taken was to develop suitable electronics to replace the electronics of a commercially available electromagnetic flowmeter normally used for steady-state operation. Use of the commercially available flowmeter body, which includes the magnetic coils, core, and signal electrodes, provided a relatively economical means of fabricating the transient flowmeter. A transient flow calibration facility consisting of a free-falling water column was also designed and built. Results of the calibrations are presented and show that the flowmeter can accurately measure transient flows up to the …

An Indirect Sensing Technique For Closed-Loop Diesel Fuel Quantity Control, Carl A. Maccarley, Walter D. Clark, Keay T. Nakae

Electrical Engineering

Despite significant advances in electronic control technology applied to diesel engines, commercially available injection systems for automotive diesel engines remain limited by the open-loop mapping of the injection pump. An initial calibration is relied upon to translate a fuel delivery command to an actual fuel quantity. In practice, however, these two variables may be substantially different due to the effects of mechanical wear, repair, and the wide range of operating conditions. Possible ramifications of this discrepancy are excessive exhaust smoke due to overfueling, increased fuel consumption, degraded driveability, and poor idle characteristics. The major obstacle to closing the fuel control …

Ultrasonic Measurement Of The Geometric Parameters Of Gaseous Voids In Low Gravity Fluid Containers, A. T. Patten, William W. Durgin

Office of the Provost Scholarship

A demonstration system for the ultrasonic gauging of fluids in low-gravity has been designed and tested. For purposes of simplification, it was assumed that vapor within a liquid container in low-gravity would form a spherical bubble which would float freely in the container. The project was designed to show that ultrasonic techniques could be used to determine the geometry of the resulting sphere given a worst-case transducer arrangement. The motivation was to simplify transducer mounting requirements so that propellant or other storage vessels could be fitted with ultrasonic gauging systems with a single or perhaps a few transducer penetrations. Data …

Self-Mode-Locking Of A Semiconductor Laser Using Positive Feedback, Dennis J. Derickson, R. J. Helkey, A. Mar, P. A. Morton, J. E. Bowers

Electrical Engineering

A new mode-locking technique, self-mode-locking, is described which uses the detected optical pulses from the mode-locked laser as the active driving source. This technique forms narrow-width mode-locked optical pulses at low repetition rates without the use of a microwave synthesizer

Canal Control Training, Charles M. Burt

BioResource and Agricultural Engineering

When compared to other industrial processes, irrigation processes are poorly controlled. Due to the unpredictable and uncontrollable nature of many present aspects of irrigation, a high degree of non-transferrability, or "art", is associated with irrigation. The Irrigation Training and Research Center (ITRC) at Cal Poly is dedicated to finding a retirement home for "Art". T

There is a great potential for excellent on-farm irrigation water management. Many tools (center pivots, linear moves, surge irrigation, drip, laser land grading, to name a few) exist to enable farmers to distribute water evenly across their fields. Other tools (computerized irrigation scheduling programs, automated …