Engineering News 7920

Elephants, image enhancers, & moment of inertia

Austin, TX--Frankly, we were bummed when we got a few pencil marks on a favorite image from a family vacation that we wanted to post on our web site: A hungry elephant at the Buenos Aires zoo adjusting his moment of inertia as he strained to reach an errant peanut.

Trying to erase the marks only did further damage to the emulsion layer. Then we found out about a new image enhancement correction technology called Digital Ice from Applied Science Fiction. Integrated directly into the scanner, it works by capturing and mapping the surface defects, then removing them to produce a clean scan. In contrast, photo editing programs are used to improve a scanned image, which can muddle it up further.

Although President and CEO Mark Urdahl will not divulge exactly how the technology works, he did say that it involves special software and certain hardware modifications. Depending on the particular scanner, changes to the filters, light sources, optical-path, mirrors, change angles and light frequencies may be necessary.

Eager to test out the claims, we asked Urdahl to produce a clean scan of our ruined slide. And--voila--our baby pachyderm looks as good as new. "Scanners are notoriously unforgiving, and that has been one inhibitor to wider use," says Urdahl. "What we're doing is taking a step to reduce those inhibitors."

Add-on bike shock has traffic stopping police

Chicago, IL--"When I'm chasing somebody on my bike and I really crank down on the pedals, I don't get that annoying pogo'ing effect anymore," says Ray Ranne, a police officer with the Chicago Police Bike Patrol Unit.

That's because Ranne and the 11 other policemen on the citywide patrol recently equipped their standard-issue Trek Mongoose mountain bikes with the Shockster APS, a bolt-on rear suspension system by BikeControl^TM that was featured at the Design News' booth at the National Design Engineering show in March.

The Shockster (DN cover story 4/6/98) features an active pivot system that eliminates the pedal-induced, power-sucking suspension movement Ranne complains about. Like all suspension systems, it is designed to prevent vibrations caused by rough road surfaces by controlling the damping forces.

Comfort was one of the main reasons that the Bike Patrol selected the Shockster APS. The patrolmen put in 8-hour days in the seat from Memorial Day to Labor Day, logging around 25 miles a day. Last year, they issued 17,000 parking citations in the process--generating enough money for the city to buy everyone a titanium frame! But their patrol route, which incorporates some 18 miles of Chicago's lakefront area, also involves some pretty serious, if unique off-roading.

"We take these bikes just about anywhere we need to go. I've raced through building lobbies, up and down staircases, and along the North Pier waterfront. Once I chased a guy through the dining area of a busy restaurant, right out into an adjacent food court, up an escalator, and out the front door into the street. Caught him, too," says Ranne.

Ranne, who functions as the unit's unofficial equipment evaluator, gives a thumbs-up to the quick install (inside 15 min) and easy maintenance. "We clean the bikes once a week, and whatever grit does get on them, we just wipe off with a rag or blow it out," says Ranne. "The shock also looks cool. Instead of me stopping them, people are stopping me on the street to ask what it is."

Ford, and your mom, improve processes

Ames, IA--There is always a better way to accomplish any job, as your mother probably used to say. Just to show her she's right, consider sending her a copy of Task Analysis Toolkit^TM, the newest release from Engineering Animation Inc. (EAI, Ames, IA). The software helps identify and correct elements of industrial tasks that decrease productivity and expose workers to safety risks. Your mom would certainly appreciate identifying YOUR productivity errors!

Eight ergonomic tools--the National Institute of Safety and Health lifting analysis, rapid upper limb assessment, low back spinal force analysis, static strength prediction, metabolic energy expenditure, manual handling limits, fatigue/recovery time analysis, and posture analysis--work in conjunction with posturing, antropometry, and simulation information from EAI's Jack(R) 2.1 human simulation software. Users define a virtual human, position them in the most strenuous posture during a given task, specify the load of the handled object, and run an analysis.

"The Task Analysis Toolkit and Jack 2.1 enable organizations to define and optimize manual workflow, and anticipate and avoid ergonomic hazards in a virtual factory, before committing to expensive tooling," says Marty Vanderploeg, EAI executive vice president and chief technology officer.

Like many mothers and all automobile manufacturers, the Ford Motor Co. wants to streamline company processes and drive down vehicle development time and costs. To help in this never ending quest, Ford incorporated EAI's VisMockUp(R) digital prototyping and Jack software. With these, any department including engineering or marketing, can access, view, mark up, analyze, and perform human simulation studies on digital models. This is the next major step in Ford's C3P initiative--a project that integrates all of the company's product development and manufacturing processes in order to generate a paperless model.

EAI acquired Jack human simulation solutions when the company recently bought Transom Technologies Inc.

MIT Class of 2002

MIT still attracts some of the best and the brightest engineering students, who seem tobe getting even better and brighter. More than one-third of the incoming class of 2002 were class valedictorians, while 4% scored double 800s on their SATs.

Terminal block/tool eases wire connection

Chicago--The Heim Group, an OEM of stamping presses, builds machine tools for the metal forming industry. These products feature dozens of components and many junction boxes with terminals and wires that need to be connected.

"Presses create a vibration intensive environment," says Electrical Engineer Steven Young of the Heim Group. "When these giant hammers are in operation, anything installed on them shakes so severely that it can cause loose wire connections and frequent machine stoppages."

To ease the potential for vibration, the company decided not to use a screw terminal block to make the wire connection, which can take even an experienced operator about 45 sec to install. Instead, the company chose to use an ADO DIN-rail-mounted terminal block from Entrelec Inc. (Irving, TX).

The ADO terminal block uses insulation displacement technology to reduce installation time and make a reliable connection that is vibration resistant. "A single wire connection can be made in less than one-third the time it takes to install a wire inside a screw terminal," says Young. And, there is no need for extra tools because Entrelec provides a single tool.

According to Young, screw terminals require a lot of wrist action and the handling of multiple tools. Wire insulation must be stripped from the end to expose the conductor. If it is not stripped back far enough, the terminal may clamp down on the insulation instead of the conductor, making it useless.

In addition, adjacent wire strands can touch, causing crossed connections when power is applied. Connecting two wires to a terminal requires twisting the ends together and forcing the pair into the terminal.

"This more than doubles the installation time and it risks making a poor connection or no connection at all," says Young. Not to mention that any connections have to be visually inspected.

"Connecting wire to an ADO terminal is fast, easy, and neat," comments Young. "There is no risk of adjacent wires touching and affecting circuit integrity because insulation is never removed to expose the conductor strands." With the ADO, it is not necessary to do a visual inspection because if the connection is not made properly, the tool will not release.

More than one wire may be connected to the same terminal without having to twist wires together. In the case of a mistake that requires wire removal, the installation tool has a built-in removal mechanism for disconnecting a wire. The wire can then be reconnected.

"Since we started using the ADO terminal blocks on all of our machine tool applications, problems with loose wires have disappeared and our installation time has considerably reduced ."

To see an animated demonstration of ADO technology, go to http://www.entrelec.com/pages/catalog/aboutado.htm.

Engineering cyberpage

Hot Spots in Cyberspace Job surfing the easy way

By Paula Porter, Internet Editor

NationJob Online Jobs Database (http://www.nationjob.com/engineering) is a free service that is quick and easy to use. With a separate page devoted to just engineering jobs, users can scroll down and find the job they are looking for, look for a job with a particular company, or use the fairly robust search engine. Complete job listings are here, including experience required, duties, compensation, and complete contact information.

Searching for the perfect job

Not only can you find a job at http://www.engineerweb.com, but you can also check out what the mean average salary of a mechanical engineer was as of April 1, 1999 ($50,648). You can find jobs by industry and states here. While not as many listings as the other sites, it's one worth coming back to often.

Engineeringjobs.com hits the spot

Another excellent site lets you send out the old resume to 500 engineering recruiters with the click of a mouse. There's also a section on the site for contract engineering jobs only. More than a job listing site, Engineeringjob.com (http://www.engineeringjobs.com ) also has links to engineering tools and references, and societies and organizations.

Job shopping at the Career Marketplace

While this site is all encompassing, it does have sections for engineers, broken down by specialty. It lets you pick jobs posted within the last 30 days or 31-60 days and over 60 days. Job information is comprehensive and the site is easy to use.

For even more websites with job listings, check out www.designnews.com/webex/joblink.html

Y'all come back now, ya hear?

One of our goals at www.designnews.com is to keep you coming back for more. That's why our site is updated several times a day with news from Lexis-Nexus, industry reports and new products among others. We've also added a new Careers section which features employment web sites specifically for engineers. In addition, our new Careers section offers links to past career-focused articles and other web sites to make you a better engineer.

This is just one of the new areas of our site to keep all engineers current with the latest, up-to-the date information. And another way we are keeping this commitment to you is our newest addition--a bi-weekly email newsletter. Our first newsletter went out to engineers who specify plastics. Each newsletter features a brief article that is written specifically for the newsletter. It's the first place you can find out the very latest information--be it a new product, a new application, or a new twist. In the future we will be adding even more specific newsletters. If you'd like to be put on the email list, head to www.designnews.com and look for the Newsletter button.

And keep coming back to www.designnews.com to stay on top of your job.

'Fuel cell-powered cars will be on road in five years,' report predicts

Detroit--Today's internal combustion engine will be tomorrow's steam engine. So predicts a report on "New Generation Engines" issued by the Economist Intelligence Unit (EIU). The study warns that it "would now be futile for any manufacturer to undertake any fundamentally new internal combustion engine program, as it would be obsolescent before it could pay for itself."

The EIU editors note that the fuel cell-powered electric vehicle (FCEV) has evolved so rapidly that several companies, led by Mercedes, Toyota, and Nissan, will launch FCEVs between 2004 and 2010--at least five years earlier than previously predicted. The main practical drawback of fuel cells--high cost--say the EIU editors, has now been overcome. Intensive design and development work over the past five years on "automotive size" cells in high volume has yielded dramatic cost reductions, they note.

Another factor in favor of fuel cell-powered vehicles entering the market, say EIU editors, is that they can offer most of the emissions and other environmental advantages of a battery-powered electric vehicle (BEV), while having the range and convenience of refueling provided by a liquid fuel tank. The liquid in this case, the study forecasts, is most likely to be methanol, which, having lost favor as an alternative to petrol in internal combustion engines for technical reasons, is now attracting intense interest as a promising hydrogen-yielding fuel.

What about electric vehicles? As a result of the advance in fuel-cell technology, EIU says that research teams are already scaling down their work on batteries. The study reveals that Volkswagen and Mercedes are moving away from the BEV towards FCEV and hybrid electric vehicle (HEV) development. However, the HEV "window of commercial opportunity" is shrinking because of the rapid advance of the FCEV, warns the EIU.

Dow to provide durable goods subassemblies

Midland, MI--Dow Chemical has formed Concepture, a new business unit geared to provide durable goods subassemblies from concept through manufacturing. Initially, Concepture will focus on the large-appliance industry and then broaden its offerings across the durable-goods marketplace.

Joining up with Concepture is Derby Industries Inc. (Louisville, KY), a producer of subassemblies for the durable goods market. Derby will provide the manufacturing and assembly portion of the package, as well as support logistics for just-in-time delivery of the subassemblies to Concepture customers.

"There is excellent value to be gained from the well-integrated and orchestrated combination of material science, product design, engineering, lean manufacturing, and assembly processes," says Steve Lepper, business director for Concepture. "Very reliable and functional subassemblies can be designed to be more cost effective and versatile by consolidating parts to reduce manufacturing complexity and parts inventory, while increasing ultimate product design freedom. It is possible to streamline production, reduce the supplier base, and minimize scrap while improving product quality."

In the past, Dow has provided design and engineering support, as well as material and process expertise, for many plastic-enabled technologies. Concepture will draw on Dow's capabilities in these areas, and also will specify and use materials and products from other sources, if needed, to enhance performance, aesthetics, or economies, Lepper adds.

Guiding the design engineering function for Concepture is Robert Cleereman, director of Dow's Materials Engineering Center. "In the past, there has been a reliance on traditional solutions for the link from concept through assembly," Cleereman notes. "Conventional component suppliers had little to gain by encouraging a change in how products are designed and built. But, for many durable goods manufacturers, that is changing. With reduced internal resources and a requirement for more innovative and cost-effective products, they are looking outside for solutions. That is where Concepture fits in."

PLC reduces panel size 25%

Appleton, WI--Things are definitely looking up at Waupaca Elevator, one of about 40 companies that serve the residential elevator market. By deciding to manufacture control panels in-house, rather than purchasing panels from an outside vendor, the firm:

Cut two weeks from the production cycle

Other A-B products such as Bulletin 100 contactors, 193 overloads, 1492 terminal blocks, 802A limit switches, and Bulletin 700 relays helped the company streamline its hydraulic elevator/control panel-manufacturing process. By taking advantage of the latest generation of programmable logic control, the company gained more mastery over production, reduced downtime, and can invest more resources into future elevator technologies, according to Waupaca's General Manager Bill McMichael.

The micro-PLC reduced the time Waupaca spends designing, building, testing, installing, and troubleshooting elevators by 50%. Furthermore, it allows Waupaca to add two key features without increasing the control-panel's cost; LED lights that quickly identify problems such as power failure, absolute overtravel and motor overload; and built-in EEPROM memory. EEPROM allows Waupaca to develop a single program and use it as the basis of all its elevators and dumbwaiters. The program has cut design and installation time in half, according to McMichael, and has virtually eliminated errors that result in re-testing the control panel and trouble-shooting the elevator.

Waupaca decided to manufacture control panels in-house instead of purchasing completed panels from an outside vendor to gain control over production and testing. "In the past, we were trying to troubleshoot when we didn't really know the inner workings of the control panels. We didn't make them here so we weren't experts at how they were supposed to work," explains McMichael.

The outside vendor Waupaca Elevator previously hired to manufacture its control panels used proprietary, relay logic devices and custom control cards to control the elevators. The relays managed the elevator's door interlocks, call lights, floor counting, absolute overtravel, and floor leveling, among other functions. "Because relay logic control panels frequently contain between 20 and 50 relays, panel design, building, installation, and troubleshooting can be very labor-intensive," explains McMichael.

After deciding to build the control panels in-house, Waupaca searched for a solution that was more cost-effective and less labor-intensive than hardwiring. They found that using solid-state versus electromechanical controls could help them reap many pre- and post-installation benefits.

"Solid-state devices suffer from less wear and tear, which results in reduced maintenance. They often provide more advanced features than electromechanical devices as well," says McMichael. These facts steered Waupaca Elevator towards selecting the MicroLogix 1000, a 32-I/O micro-PLC, along with other Allen-Bradley controls.

Waupaca Elevator's reputation for reliability is already starting to pay off. They have recently moved to a larger facility to accommodate their growing business. McMichael attributes their growth in part to the confidence they have gained by having the resources to troubleshoot and accurately fix problems that they couldn't fix before. This has been possible due to extensive programmable controller training from Allen-Bradley and local distributor Warner Electric, in addition to the skills Waupaca Elevator employees have acquired on the job. In fact, after several hundred installations Waupaca has not needed to make even one customer visit.

U.S. faces space-launcher stand down

By Rick DeMeis, Senior Editor

Washington--Not since 1986, with the Challenger accident and concurrent failures of Titan, Atlas, and Delta II rockets, has the U.S. confronted a stand down of a large portion of its booster fleet. While the shuttle has been made more reliable, since last summer six launches of expendable boosters have failed. President Clinton asked Secretary of Defense William Cohen to fathom out "root causes behind the recent failures and take corrective action." His final report is due around Thanksgiving.

Here's a run down of this losing streak:

August 19, 1998: wiring damage causes a solid rocket booster on a Lockheed Martin Titan IV to explode, destroying a classified communications satellite.

Root causes. While seemingly unrelated, experts are looking for common trends. Causes mentioned include: more reliance on computer modeling rather than full, all-up booster testing; over-emphasis on lowering booster costs, perhaps prompting short cuts; and fewer middle-age, more experienced aerospace engineers, leading to a loss in industry "corporate memory."

One of these seasoned veterans of the Rocket Mafia toldDesign Newsthat, "fewer launches today on each booster make it harder to keep workforce morale and skills up. The failures are random. It doesn't seem to be a design problem, but quality control and human error--just not doing things right--and should be traced quickly."

Ol' sol and CAD power vehicles in Sunrayce '99

St. Louis, MO--Solar cars, Autodesk, and a religious-based, liberal arts college. What do these three items have in common? Jonathan Hess, a sophomore at Principia College.

Thanks to Autodesk donating a copy of its 3D solid modeling software, Mechanical Desktop(R), Hess, 20 of his colleagues, and their solar car, the Ra3, qualified for the 1999 Sunrayce in June.

The biannual event, sponsored by the Department of Energy, General Motors Corp., and Electric Data Systems, promotes student interest in new technologies. This year's 1,300-mile race started in Washington DC and finished nine days later at Epcot in Orlando, FL.

Principia, a small school for Christian Scientists, has no engineering department. The Ra3, named after the Egyptian sun god, began in the Fall of 1997 simply as a physics project. But the result was a vehicle as sophisticated as any standard automobile.

"The front and rear suspension systems each comprise 50-60 parts," says Hess. "I may be a college student, but, this is as tough and real a project as any engineer has to deal with."

The group visualized the assemblies to make sure all the parts fit together properly. "When we were trying to determine how to mount the shock absorbers on the front suspension, we weren't sure how large to make the A-arms," he says. Double A-arm suspensions are similar to race-car suspension systems. "However, thanks to Mechanical Desktop's solid modeling capabilities and our knowledge of the size of the shock absorber, we designed the A-arms around the shock absorber and mounted them without interfering with any other parts. Because we could test it on-screen, we already knew that when we built it, all the parts would fit together perfectly."

Well, most parts. "Our rear suspension is like the rear suspension on a Hummer," jokes Hess. It was designed separately from their in-wheel motor. When it came time to assemble these two parts, the original suspension bent. "We didn't build it strong enough the first time, so we redesigned it. Maybe over designed it," he adds, smiling.

The students chose chrome moly steel for the frame and chassis. "It is a bit heavier than we would have liked," says Hess. "The car weighs close to 1,200 lb. But it is safe, with an all-around safety factor of 2.5."

Hess and his team started building the mold for the body while the car's chassis was constructed in North Carolina between September and December of 1998. He says, "We were able to do both tasks concurrently because we could generate drawings of the chassis and the body, fit them together in Mechanical Desktop, and send the drawings to fabricators."

"Without Mechanical Desktop, many situations could have caused major headaches," he adds. For example, decisions needed to be made regarding location of solar cells on the vehicle's roof. Because solar cells vary in size, each design layout was different depending on the cells used. "When we finally made a decision," says Hess, "the updated geometry provided us with a final drawing without having to entirely redraw the body. Parametric dimensioning is a key tool. This feature saved us hours and hours of redrawing work."

With geometry as complex as their design, modeling it in 3D is the only way to go, says Hess. "We've been able to design the whole car using Mechanical Desktop. That has been a real advantage." The last Principia car built for the solar car race, held in June 1997, was designed from napkin sketches. "Using professional CAD software has enabled us to treat this work as it should be--a true engineering project. We have been able to design parts in solids as well as review designs before anything on the car is actually built."

To compensate for their limited engineering knowledge, the team exported CAD drawings to an FEA expert who donated his time to perform stress analysis on the parts. "Mechanical Desktop allowed us to communicate more effectively with outside vendors," Hess adds.

For Hess, getting started using Mechanical Desktop was easy. He had an advantage because he worked as an intern at Autodesk for two summers during high school through the company's School-to-Work program. "While there, I learned to use AutoCAD(R). Once we implemented Mechanical Desktop at Principia, I spent two or three days intensely using the software. Within two weeks, I felt very confident. I especially appreciate its solid and mechanical modeling capabilities, as well as the ability to transfer 3D models to 2D drawings so they could be fabricated."

Perhaps the biggest challenge for the group was that even though this is the third solar car Principia students built, there was no documentation on previous cars. "We started from scratch," Hess says.

As a result of the project, Hess, presently a computer science major, is considering a career switch. To what? What else? Engineering, of course.

At presstime, the '99 Sunrayce winner had yet to be declared. For up-to-date results, visit: www.sunrayce.com.

Stop sign an awards show stopper

Boston--What do an all-plastic stop sign, garden tractor, immunodiagnositic system, and a plastic ski have in common? They all walked off with awards at the SPI Structural Plastics Div.'s 27th annual conference and design competition.

The all-plastic stop sign, winner of the Conference Award and produced by ALL Sign Products, Inc. (Pompano Beach FL), eliminates a weakness in many of today's traffic signs--loss of color and retroreflectivity over time. It's a phenomena normally experienced by signs designed with a reflective sheet on an aluminum blank. The all-plastic sign retroreflects light back to the eyes of a driver by integrally molding precisely engineered cubed corner retroflectors of polycarbonate (PC) as the backside of the sign face.

A separately molded translucent PC back plate, which provides an air gap for further light gathering, is sonically welded to the face. This allows ambient sunlight to penetrate and illuminate the sign at sunrise and sunset, time periods when an aluminum sign usually is silhouetted.

The sign's 30-inch, regulation octagonal back also incorporates structurally reinforcing radial ribs. Use of the PC (Bayer's Makrolon(R) resin) and the integral UV- and graffiti-proof film (Bayer's Makrofol(R) EPC) give the sign added life. Moreover, the materials are recyclable.

The upper and lower hoods of a garden tractor designed by Henry Dreyfuss Associates, (New York) for the John Deere Horicon Works (Horicon, WI) and molded by the Bemis Manufacturing Co. (Sheboygan Falls, WI) took top honors in the Environmental Award category. The co-injected hoods employ PET/PC (GE Plastic's Xenoy 2731U) for the skin material, and off-spec PET/PC, PBT/PC, or ABS for the core.

The upper hood features a long flow length with a thin wall (31/2 mm), while the lower hood makes use of sequential valve gating to keep the wall thickness minimal. The high-gloss-finish parts have no knit lines on visible surfaces. Co-injection molding enables the product to be completely encapsulated within the skin materials, and the engineering resins are easy to recycle or reclaim. The result: a 20 to 30% reduction in processing costs, with no negative effect on impact performance or structural integrity.

On the medical front, an immunodiagnostic system produced by Chiron Diagnostics Corp. (East Walpole, MA) and molded by GI Plastek (Newburyport, MA) won the Medical & Scientific award. The 29 reaction injection molded (RIM) parts that make up the system include enclosure panels, top cover, and reagent box. The computer-controlled system processes and analyzes samples using a chemical technology that creates light and a sensitive light-gathering system to provide test results.

In addition to RIM, production of the system incorporates pressure forming, injection molding, blow molding, and rotocasting. Wall thicknesses range from one inch to as thin as 3/16 inch with no post blowing.

The reagent box at the core of the system typifies the complexity of the project. Critical to the box's design was the selection of a polyurethane structural foam (Bayer's Baydur 726) that would provide a consistent temperature within the box. Early design involvement by the molder enabled the consolidation of the box from four components to a single part.

Snowmobilers will appreciate the plastic ski designed and molded by Camoplast Inc. (Sherbrooke, Quebec, Canada), winner of the Recreation and Leisure Award. Its design enables snowmobile makers to replace existing heavy metal skis that tend to corrode, collect snow, and are hard to steer with a lighter, competitively priced plastic model.

Said to be the first blow-molded all-plastic ski, the design features a patent-pending integrated handle. It also includes a combination of solid and hollow sections. In-mold technology places graphics and logos directly on the skis during the molding process, eliminating decals.

High-school students and teachers try engineering

By Laurie Toupin, Associate Editor

Fredericktown, OH--One company in rural Ohio hopes to replenish its supply of engineers by educating students and teachers alike. Terry Divelbiss, president of Divelbiss Corp., got involved in the local school district's School-to-Work (STW) program about three years ago. Divelbiss manufacturers custom-designed industrial controllers, PLCs, and industrial computers for applications ranging from loading dock controls and shooting ranges to pump controllers.

Through this program, teachers and students work for Divelbiss as engineering apprentices, giving both groups a chance to see "real-life" engineering in action. "This is important," says Divelbiss, "because many of the students and teachers had no idea prior to the program what engineering is about and how wide the job opportunities are."

Part of the program involves mentoring. A student will work with an engineer two hours a week for an eight-week-period to get an idea of what the job involves. In another portion of the program, called shadowing, the students closely follow an engineer around for a day.

"We try to hitch students with different engineers to give them a mix of hardware, software, CAD, and technical support," says Divelbiss. If some one says he is interested in computers, Divelbiss pairs him up with an engineer to shows how computers operate the machine tools as well as other equipment.

"By the end of the program, we want to be sure the image in the students' minds fits with reality," he says. "We talk about the engineering responsibilities of solving a customer's problem. And we stress the fact that engineers don't do design work everyday. In fact you won't do the same thing everyday."

Some students come out of the program and decide that engineering isn't for them, Divelbiss admits. But the ones that decide positively become potential employees after graduation.

A change in curriculum. The teachers get a lot out of the program as well. "At first, we were walking around Terry's plant, listening to him, with glazed looks on our faces," says Lori Ackerman. "We didn't know what went on out there. Now this interaction and knowledge is an integral part of our curriculum."

After his experience in the School-to-Work program, high school math teacher Robert Moore developed an interactive algebra course. Students learn by working through a practical application or series of problems. For one assignment, the class drafted and designed a conveyor belt, answering such questions as: "How high should the conveyor belt stand off the ground? How fast should it move? What is the best method for powering it?" The first year offered, only eight students signed up. Now the demand is so great that next year Moore will teach two classes.

In addition to Divelbiss, other local businesses offer teachers and students similar opportunities. Moore took part of his summer vacation to work for F.T. Precision, a Honda parts supplier, to understand the math required in today's engineering and manufacturing environment.

The teachers can be more effective in the classroom, says guidance counselor Kathie Brown, by answering for the kids one basic question: "How does what you study in school apply to your life?" Ninety percent of teens say school would be more interesting and meaningful if taught in connection with careers, according to Teen Attitudes Toward Work, published by Bruskin Goldring Research, 1994.

It's working. School-to-Work is a federally funded national program. Former Fredericktown School District superintendent, Robert Casey initially wrote the grant to get the ball rolling. Each state applies to the government for block grants,and individual school districts apply to the state for money. The program at Fredericktown began three years ago. While still too soon to determine long-term impact at this school district, nationwide results have been positive.

In Philadelphia, students involved in the School-to-Careers programs had higher grade point averages and a significantly lower dropout rate than students not involved, according to the Philadelphia School District Study.

The Westchester Institute for Human Services Research Inc. found that seniors in New York's School-to-Work initiative took more advanced science, mathematics, and computer science courses than a less involved comparison group.

A study analyzing the differences between Boston's ProTech (STW) class of 1997, Boston's public school students, and the national average showed that those students involved in STW have a higher employment rate after graduation and were 16% more likely to attend college in the year following graduation.

In addition to just enjoying working with the students, Divelbiss says, "I get my eyes on talent that is coming out of the school and see future engineers and employees. Talented people are hard to keep."

Fredericktown is a small, rural community in the middle of Ohio, with 435 students in the high school. "Before, young engineers wanted to go to the city," says Divelbiss. "Now we can give them an idea of who we are, offer them a co-op, and hopefully they will become long-term employees for us."

If interested in starting a School-to-Work program in your district, visit: www.stw.ed.gov.

Advice from engineers: Be flexible

Newton, MA--Everyone has a job, but how many of us really have a career? Several career engineers offer sound advice for those thinking about engineering as more than just a job:

Jeffrey Jurs, manager of product development at Omron Electronics Inc. (Shaumburg, IL): "New engineers need to understand the nature of engineering--optimizing a huge variety of technical, practical, and political concerns to meet a business need. Engineering is not just sitting at a computer drawing all day. It is providing something that can be sold at a profit in a given amount of time, at a given investment cost, at a given price. The best solution to a business problem is not necessarily the 'ideal' design."

PLCs pound the pavement

By Rick DeMeis, Senior Editor

Atlantic City, NJ--Think computers can simulate the repeated pounding fully loaded jetliners impose on taxiway pavement materials and structure? Well think again. According to Andrew Cook, project manager for Multitech, an Automation Solutions International (ASI, Petaluma, CA) company, once any deterioration occurs, the material behavior models don't hold up.

That's why the company helped install the National Airport Pavement Test Vehicle at the William H. Hughes FAA Technical Center here. In addition to pavement research, the facility also has bottom line benefits. While runways worldwide are built to handle just about any airliner, the taxiways leading to them can vary enough such that airports are classified according to the type of aircraft and loads they can accommodate. Airliners are also rated as to how much stress they impose on the taxiway subgrades and landing fees charged accordingly. Being able to prove a landing gear configuration imposes reduced stress will allow airlines buying that type to reduce operational costs.

"The vehicle is striking," says Cook--which is an understatement. The 100- x 87- x 38- ft tall carriage weighs 1.1 million lb and rides on twin 1,100 ft long railroad tracks within a 1,400-ft building. Within five seconds and 20 ft, the tester accelerates to 5 mph. After a 1,000-ft test run over various pavements and subsurface configurations, 32 disc brakes (two per axle) bring the vehicle to a stop. The tester can reach 15 mph, but acceleration and braking distances result in a test run of only 50 ft.

"Our challenge," notes Cook, "was to allow the drives and motors to share the load such that one set of motors would not be dragging, or pulling, the other." The configuration the controls system company came up with uses a PLC to govern four Mitsubishi inverters powering 16 Rueland Electric Special Series motors. Each inverter handles four motors in two driving units, for a total of eight on each rail track. Total power consumption is 1 MW during acceleration.

Fiber loop. For speed control, a fiber-optic loop connects the PLC to each inverter. "The desired speed is set and the inverters are adjusted to give some 'slip' in the motors to share the torque between motors," Cook says. An encoder on one motor provides speed feedback to the PLC.

Hung from the superstructure that links the dual drive units on each railbed are two carriages that each mount an aircraft landing gear assembly, or bogey. A Mitsubishi brushless servo drive on each carriage can vary the separation between the landing gear, duplicating different aircraft geometries. A PLC in each carriage governs hydraulics for three load modules, which all together apply upwards of 1 million lb total downforce.

Nine sections of pavement can be traversed on each run. Cook says about 1,000 sensors in the subgrade collect data on stress, shear, and moisture. "By observing failures to get a picture on what happens in the real world, we can correlate results to the California Bearing Ratio (CBI), a pavement strength scale," he notes.

In developing the tester, Cook highlights "It was similar to coming up with eight or nine machines and integrating them. Using Mitsubishi's Medoc Plus IEC PLC programming package allowed Multitech designers to build separate modules and then tie them together in one package, programmable over an Ethernet." The system can run 24 hours a day, unattended for up to 10,000 runs to pavement failure. It is also capable of control from an onboard cab for specialized non-continuous work, including higher-speed and potential impact tests.