Jeffrey R. Mountain

Triboelectric charging of polymer powders in fluidization and transport processes

Steady flow of powder at a desired rate is a necessity for controlling thickness and uniformity of the deposited powder layer in electrostatic spray painting. In most powder coating applications, the polymer powder is fluidized to transport the powder to the spray gun using a powder pump. The powder delivery tube is often long; sometimes in excess of 10 m. During fluidization and transport, the powder particles acquire electrostatic charge due to triboelectrification. This tribocharging of powder can present some problems: (1) agglomeration of powder due to bipolar charging, (2) deposition of charged powder on the inner wall of the transport tube, and (3) biasing of the final charge-to-mass ratio (q/m) distribution of powder exiting the corona gun. In this study, we investigate the role of tribocharging in fluidization, flowability, and q/m distribution as functions of particle size distribution (PSD), fluidization time and transport tubes of different materials. A particle size distribution shift due to the polarity of the bipolarly charged particles is shown. A brief discussion is presented on minimizing the adverse effects due to powder tribocharging, therefore improving spray uniformity.

Electrostatic effects on first pass transfer efficiency in the application of powder coatings

Two important process conditions desired in most powder coating applications are: a high first pass transfer efficiency (FPTE) and uniformity of the powder layer covering the surface to be coated. Both of these desired outcomes are influenced by the electrostatic properties of powder and electrostatic parameters involved in the spraying process. An FPTE, greater than 90 percent may eliminate the need for recycling of the overspray in some applications, thereby, permitting fast color changes. Many industries are unable to switch from solvent based coatings to powder coatings because of the long color-change time required in current powder coating processes, To obtain a high FPTE, a clear understanding of the electrostatic phenomena involved in the process is desired, but the complexity of the process, particularly such conflicting requirements between high FPTE and strong adhesion of the powder layer, between high current density for charging and elimination of back corona require optimization of the process based on theoretical and experimental investigations. This paper describes relationships between FPTE and (1) ion current density and (2) particle size distribution (PSD). Theoretical relationships between process parameters and electrostatic effects and how process conditions can be optimized for a high FPTE and uniformity of the powder layer are discussed with experimental results. Possible empirical steps that can be used to optimize FPTE are presented.

The use of applied process control systems design to attract engineering students

Hands-on, design oriented experiences have been shown to increase awareness of engineering as a profession and to attract students to enter engineering programs. Most of these programs, while very successful, specifically target highly specialized industries. In an effort to appeal to a wider variety of engineering disciplines, the University of Texas at Tyler, with the aid of National Science Foundation grant funding, has proposed to use the multidisciplinary process control industry as a theme to attract students into the engineering profession. The topic area of process controls has applicability to a wide range of engineering disciplines including agricultural, chemical, electrical, mechanical, and petroleum engineering. This paper will describe how the process control breadboard, a proof of concept system developed to attract and retain engineering students, is being used as both a demonstration tool and a hands-on design, build, test activity for K-12 outreach activities. Preliminary results from initial outreach activities will be presented along with the plan for future activities to stimulate interest, awareness and enrollment of highly qualified engineering students.

Multi-section course management using 3D spreadsheet tools

The paper describes a spreadsheet based method to assess and influence the grading uniformity of graduate teaching assistants in multi-section courses with large enrollments. The method developed is based on a common-use grade spreadsheet issued to the teaching assistants. Its features include the option to drop low-score items from grade determination, the application of curve factors, the determination of averages and standard deviations for all course activity items, and diagnostic fields to indicate missing data. The most important strategy of the method is to periodically merge the individual grade-record spreadsheets into a three-dimensional spreadsheet developed for the course coordinator. This technique has the advantage of permitting continual assessment of grading timeliness, grading uniformity, and instructional effectiveness across all sections. As a result, feedback and guidance involving these issues can be provided to the graduate teaching assistants in a timely and efficient manner which directly benefits currently enrolled students. Extensions of the method to other instructional areas are cited.

Fuzzy logic motor speed control with real-time interface using an 8-bit embedded processor

Fuzzy specific hardware systems, or the adaptation of standard embedded controllers, are the common approaches for real-time fuzzy logic implementation. High speed applications may require the more sophisticated hardware, but most embedded control applications do not have the high speed processing requirements that necessitate the cost prohibitive enhanced hardware. A review of embedded control fuzzy logic applications indicates a preference for 16-bit architectures; devoting significant processing resources for fuzzification, rule application, and defuzzification. While faithful to the foundations of fuzzy logic control, processor demand can limit a controllers ability to handle peripheral I/O interfaces. This paper describes a generic, hybrid approach suitable for unenhanced 8-bit microcontrollers and adaptable to most single input, single output systems. A motor speed application with real-time I/O interface provides proof of concept performance data and highlights limitations.

Development of a Breadboard System for Process Control Design: Part I

This paper presents initial planning for the development of a process control breadboard system. The proposed system will be composed of mechatronic, thermal/fluid, and control elements that using simple hand tools can be easily reconfigured by undergraduate students. An approach for integrating the breadboard system throughout the curriculum, enhancing the design education experience beginning with freshmen and continuing through the senior capstone experience, is proposed. This system is expected to significantly enhance the ability of students to work with a thermal/fluid-based process control system, and to provide the opportunity for design/build/test realization for a variety of completely functional systems. A sampling of configurations will be presented to demonstrate how this proposed system might be used to address an open-ended design problem with external constraints. A comparison with existing educational trainer systems commonly found at academic institutions will be presented, along with preparations for a proof-of-concept adaptation to occur during the fall semester of 2002. Support for K-12 outreach activities and EC2000 professional component program criteria will also be discussed.Copyright

A Hybrid Fuzzy Logic Approach for 8-Bit Embedded Control Applications

The real-time implementation of fuzzy logic algorithms in embedded systems typically uses two approaches: employ fuzzy specific processing hardware or adapt standard embedded controllers to implement the fuzzy logic inference process. While high speed applications may require using the more sophisticated hardware, most embedded control applications do not have such processing speed demands, nor can they justify the added expense associated with the fuzzy enhanced processing engines. A review of embedded controller fuzzy logic implementations indicates a preference for 16-bit architectures; devoting significant processing resources to perform fuzzification, rule application, and defuzzification during real-time operation. While these approaches remain faithful to the foundations of fuzzy logic control, devoting processor resources to fuzzy specific tasks can limit a controller’s ability to handle peripheral tasks, such as man-machine I/O interface. This paper describes a simplified, hybrid approach suitable for standard 8-bit microcontrollers. The generic nature of the approach allows the methodology to be readily applicable to many single input, single output systems. This paper describes the hybrid fuzzy logic approach, which is placed in context using a proof-of-concept motor speed application. System performance data and notable limitations of the prototyped system are also described.© 2007 ASME

Initiating Development of a Concept Inventory for Engineering Design

It has been stated that the topic of design is not conducive to assessment by concept inventory. While design problems are more ambiguous than problems in analytical subjects, such as physics, statics, or thermodynamics; the broader design education community of scholars might agree on a set of concepts that are essential to the fundamental understanding of design. Following a review of textbooks, industry interviews, and other literary sources, this paper will propose a set of commonly accepted overarching concepts that might form a nucleus of an engineering design concept inventory. This is intended primarily to initiate a dialog among the design engineering education community about the future development of a design concept inventory and it’s applicability in assessing the design content knowledge of undergraduate engineering students prior to entering the profession as graduate engineers.Copyright

The Status of Design for Sustainability in Mechanical Engineering Design Education

Sustainability is gaining national and global prominence as a key external constraint in engineering design. Courses in solar energy and wind energy have been common offerings, but due to their power production focus, do not address sustainability in the broader context of design. The question becomes, are undergraduate mechanical engineering programs evolving to introduce design for sustainability concepts, such as life cycle assessment, the triple bottom line, and carbon balance, in the broader context of mechanical engineering design? A review of mechanical engineering programs at well recognized universities indicates that most course offerings with definable sustainable design content remain focused on sustainable energy production. In addition, most of these courses are primarily graduate level offerings, indicating a substantial population of recent graduate engineers with limited knowledge of the scope of design for sustainability. Isolated efforts to broaden awareness of sustainability concepts were also identified and will be reported. These programs may serve as models for integration of sustainability into the general mechanical design education.Copyright

The Decline of Design Across the Curriculum

Design across the curriculum has been a cornerstone of mechanical engineering education for well over a decade. The movement was an attempt to balance the tendency of most programs to over-emphasize engineering science. Over the course of that decade, many public universities have undergone a 7%–10% reduction in the number of credits required for graduation; usually in response to legislative pressure or competitive market conditions. In some instances, these reductions were not reflected in the general education content. Although the number of technical electives within the curriculum may have been reduced, seldom have they been completely omitted. Engineering science is considered the analytical foundation upon which new knowledge and engineering design are based. In addition, new frontiers in mechatronics, nanotechnology and alternative energy sources are becoming “must teach” subjects so that the discipline can evolve. The indication is that the “Design Across the Curriculum” concept either is, or will soon be in decline. This paper will present some historical perspective, a small sample of both common “solutions,” and a few unique approaches for maintaining design across the curriculum. The primary objective, however, is to initiate a dialog among engineering educators to begin to address the balance between engineering science and engineering design.Copyright