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Clues to the Chesapeake's past
The write stuff for engineering
Faster than a speeding missile
A hang-up that honors HUT
Tear up that library card?
Easier access for disabled Web users

Clues to the Chesapeake's past

When exploring the history of an ecosystem as great as the Chesapeake Bay, the view changes depending on the scientific eye.

A zoologist might examine fossil evidence to discover early bird and animal inhabitants. The climatologist measures the spacing of tree rings to determine wet and dry periods. The paleobotanist pulls out cores of sediment to check for centuries-old pollen grains that might show traces of forest fires. And historians comb letters for fishing lore.

A new book looks beneath the surface for changes in the bucolic Chesapeake.
Photo by David Owen Hawxhurst
Such varied minds come together in a newly published book, Discovering the Chesapeake: The History of an Ecosystem (The Johns Hopkins University Press, 2001). A collection of essays born of two National Science Foundation conferences on the Chesapeake region, the 385-page book is written for the intellectually curious general reader who wants to explore the environmental history of the Bay and its watershed.

The book offers an ocean of expertise. It is edited by three Hopkins experts on the Chesapeake and its environs: Philip D. Curtin, Hopkins professor emeritus in history; Grace S. Brush, professor of geography and environmental engineering; and George W. Fisher, professor of earth and planetary sciences.

Brush, for example, in the chapter "Forests before and after the Colonial Encounter," describes how she has pinpointed early American periods of deforestation and agriculture, and subsequent effects on the Bay, partly by finding surges in ragweed pollen in sediment cores from the estuary and its tributaries. Curtin co-authors an article that examines how pathogens from Europe, such as smallpox, spread disease among the non-immune native population. And Fisher explores the Chesapeake's geological heritage, showing how the rise and fall of the ocean forced saltwater into the watershed to mix with fresh water and create a fragile, but "immensely productive ecosystem."

Many of the topics focus on threats to the Bay area: the ecological fallout of agrarian reform between 1730 and 1840; the loss of once-rich oyster populations; and the continuing impact of human populations, from Indian slash-and-burn farming techniques to current fertilizer runoff from suburban lawns.

"Today's Chesapeake Bay is only some ten thousand years old," writes Curtin in the introduction. "What a different world it was... when the region was the home of the ground sloth, giant beaver, dire wolf, mastodon, and other megafauna.

"In the next few thousand years," Curtin writes, peering forward through his scientist's eyepiece, "the ice may form again and the Bay will once more be the valley of the Susquehanna, unless, of course, human-induced changes in climate create some other currently unpredictable condition." --Joanne Cavanaugh Simpson

The write stuff for engineering

Behind nearly any cliché is a kernel of truth.

"Unfortunately, it's almost cliche that engineers can't write,'" says Hopkins writing instructor Peter Porosky, "yet it's critical that engineers go into the business world being able to write."

Porosky directs the Whiting School of Engineering's Office of Professional Communication, a recently developed effort to teach engineers, premeds, and other students how to craft grant applications, do oral and Power Point presentations, and write essays for jobs or med school applications.

"We are trying to fill a tremendous need in the academy, and in the real world," says Porosky from his office in Homewood's New Engineering Building. Just a few years old, the program has more than 200 undergraduates from Engineering and Arts & Sciences filling 16 sections of technical writing and communication courses.

Candice Dalrymple, a Hopkins associate dean, launched the program. "Our engineering students were taking writing-intensive courses that were very challenging, but they dealt with academic issues, like deconstructing poetry," she says. "Yet technical writing, business writing, and similar types of communication comprise 85 to 90 percent of what they do after they leave here."

"It's a competitive world," says Porosky, who is on the faculty at the University of Maryland, which has an established program in technical writing. "The heart of technical communication is translating difficult information to the average person so that developers, marketers, and grant givers can understand it. You need to reach people who are not specialists, but who affect the specialists." --JCS

Faster than a speeding missile

New technology that uses pure hydrocarbon fuel in a specially designed engine could power a new generation of hypersonic missiles--missiles that could travel farther and faster to strike targets within minutes instead of hours.

A direct-connect combustor rig being tested at APL.
Photo courtesy APL

A team of scientists at Hopkins's Applied Physics Laboratory has adapted an air-breathing engine first designed at APL in the 1980s to be used in such missiles. The team recently showed for the first time that pure JP-10 liquid hydrocarbon fuel can be used in the dual-combustor ramjet (DCR) engine, creating a simpler, more powerful system to sustain hypersonic flight.

"Standard rocket-powered missiles can be boosted to hypersonic speeds, but then coast and decelerate," explains Michael E. White, APL program area manager for advanced vehicle technologies. "We are trying to accomplish sustained hypersonic flight using advanced air-breathing engines."

Previous supersonic combustion engine designs for missiles have been problematic, partly because most require toxic fuel additives. Among other drawbacks, volatile additives are dangerous to carry on Navy ships.

An artist's drawing of a hypersonic cruise missile
Photo courtesy APL

The U.S. Navy, which is sponsoring the APL research, wants to improve missile range and speed over that of current cruise missiles like the Tomahawk. Sustained hypersonic missiles could, for example, more quickly hit mobile Theater Ballistic Missile (TBM) launchers or heavily defended targets, allowing American troops to remain at safer distances. Such missiles would be "dramatically faster than the Tomahawk missiles," White says. "Instead of taking an hour to hit a target, it would take 10 minutes."

While air-breathing engines are not new (airplane turbojets use air from the atmosphere), the DCR system is better geared to missiles. Under the process, the first of two combustors in the engine burns all the hydrocarbon fuel with a small portion of air, which then starts the combustion chain reaction. The by-product is mixed with more atmospheric air in a second supersonic combustor, creating the thrust needed to carry missiles at five times the speed of sound or greater (more than 3,500 mph). Officials hope the APL propulsion system could lead to advanced hypersonic missiles by 2010. --JCS

A hang-up that honors HUT

Photo by Steve Conard Engineers from Hopkins went to the Smithsonian's National Air and Space Museum in late March to help hang the Hopkins Ultraviolet Telescope (HUT) from the museum's ceiling as part of a new exhibit, "Explore the Universe." When the exhibit opens on September 21, HUT will be the first major piece of Hopkins history to join such illustrious company as the Wright Brothers' first flier, Charles Lindbergh's Spirit of St. Louis, and Glamorous Glennis, the experimental airplane in which Chuck Yeager surpassed the speed of sound.

Conceived at a time when astronomers thought the best way to make orbital observations was to build observatories that could be repeatedly flown aboard the space shuttle, HUT, built on the Homewood campus, went into space on the shuttle in 1990 and 1995. Observations made through HUT gave astronomers some of their first solid data on the intergalactic medium, the environment out of which galaxies formed.

"It was two decades of work, and it was a project of great cosmological significance," says a nostalgic Arthur Davidsen, HUT principal investigator. "I told my son that HUT was going to Air and Space, and he said going there was much cooler than going into orbit one more time," Davidsen said, smiling. "I can't go that far myself, but I certainly am thrilled because it validates the importance of the project." --Michael Purdy

Tear up that library card?

Research libraries are increasingly expensive to maintain, and available only to those who have some connection to a university, research institution, or corporation. For William Y. Arms, a solution is at hand: the digital research library.

The Cornell computer science professor came to Homewood recently to deliver the third annual Paula Hamburger Lecture. He currently has a National Science Foundation grant to develop a digital library for students in science, math, and technology.

Arms noted that the Web has begun to offer free alternatives to replace what he called "pay-per-view" research sources. Users of, for instance, can now tap all the information previously found only in Books in Print, the thick compendium all libraries purchase and stock for their users. Similarly, Web search engines like Google, Lycos, and Alta Vista are superseding services like INSPEC, an electronic pay-per-view bibliographic service for science, engineering, and computer technology.

The cost of constructing and maintaining a comprehensive digital archive will be borne, Arms predicted, by the organizations and institutions that generate the knowledge and information. That cost is trivial compared to the cost of a bricks-and-mortar research library, he said, and the user does not have to be among the privileged members of a major institution to use it.

Before the advent of the Model T, only the rich could afford cars, Arms noted. "Right now, digital libraries are like a Model T Ford. The gap between the rich man's library and the open-access digital library is closing." --DK

Easier access for disabled Web users

Internet technology has opened portals to entire new worlds for students and faculty on campuses across the globe. That is, unless you are blind, physically handicapped, or deaf.

"There is a whole class of individuals being left out of the Internet conversation," says John Castellani, assistant professor in Hopkins's School of Professional Studies in Business and Education (SPSBE).

Up to snuff? Screening programs can let you know. Many universities don't yet realize how this vast new communication resource can pose problems for prospective students who are disabled. The visually impaired, for example, face problems accessing course syllabi and discussions posted on Web sites with complex graphics. And as more college courses incorporate the Web, with some being taught solely via the Internet through "distance learning," the issue of accessibility has grown.

So have legal challenges and remedies. Complaints from students at California's community colleges prompted the federal government to take a look. And in 1998, the U.S. Department of Education's Office for Civil Rights, citing the Americans With Disabilities Act (ADA), ordered those colleges to find print and other methods for visually impaired students to access electronic information.

New federal regulations approved in December, meanwhile, require federal and state Internet sites to provide reasonable accommodation to disabled users. The rules, which are set to go into effect in late June but are under review by the Bush administration, would apply to state schools. Private universities, as well, are looking at how to upgrade, or supplement, their Web sites. And it's not just schools. Such issues will become more critical as the U.S. population ages and more Americans find themselves losing sight and hearing abilities--yet still needing access to the Internet.

Castellani, a faculty member in the Technology for Educators program at Hopkins's Columbia Center, has made wider Internet access a personal crusade. To test the accessibility of the university's site--which includes information on academic programs and faculty, application materials, maps to the university, and notes on life at JHU- -he ran it through a screening program. The Hopkins home page failed; among other problems, there was no text-only format that allows visually impaired people to use audio screen readers.

Castellani is now sharing his ideas with Hopkins and other campuses that are upgrading, or creating sites from scratch. "We need to work with universities to get the idea out there to think about this beforehand," he says. "Going back to retrofit every school's page is a mammoth undertaking."

There are a number of fixes that can help sites comply with the spirit of the federal law, and allow broader access, Castellani notes. In addition to text-only sites that allow people to use audio screen readers, designers can provide written descriptions of vital images and captioning for video to help people navigate flashy graphics or visuals they can't see. Audio materials, such as lectures, could include transcripts.

At the least, he notes, site designers should provide a telephone number, or numbers, in a prominent place so that users can call and use various assistive technologies via the phone. (Web designers can test whether their pages are disabled-accessible using screening programs, such as one created by CAST, a not-for-profit advocacy group. That program, Bobby 3.2, can be found at

"Assistive technology takes the approach that what is good for people with disabilities is good for everyone else," Castellani says. "The goal is to design the Internet to become seamless and useful for everybody." --JCS

Return to June 2001 Table of Contents

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