NIST Tech Beat - Sept. 28, 2006

Engineers at the National Institute of Standards and Technology (NIST) are developing a robotic system that may offer wheelchair-dependent people independent, powered mobility and the ability, depending on patient status, to move to and from beds, chairs and toilets without assistance.*

The lifting ability of the system, which is called the “HLPR Chair” (for Home Lift, Position and Rehabilitation), also should significantly reduce caregiver and patient injuries.

The HLPR chair draws on mobile robotic technology developed at NIST for defense and manufacturing applications. It is built on an off-the-shelf forklift with a U-frame base on wheel-like casters and a rectangular vertical frame. The frame is small enough to pass through the typical residential bathroom. The user drives the chair using a joystick and other simple controls.

The HLPR chair’s drive, steering motors, batteries and control electronics are positioned to keep its center of gravity—even when carrying a patient—within the wheelbase. This allows a person, weighing up to 300 pounds, to rotate out, from the inner chair frame, over a toilet, chair or bed while supported by torso lifts. The torso lifts lower the patient safely into the new position. The chair frame can even remain in position to continue supporting the patient from potential side, back or front fall.

In addition, the proof-of-concept prototype HLPR Chair would allow stroke victims and others to keep their legs active without supporting their entire body weight. Retractable seat and foot rest, padded torso lifts for under arms (that, when raised, act like crutches) and an open frame at the bottom of the chair facilitate leg exercises. The patient, once lifted and supported by the torso lifts, can walk as the HLPR Chair moves forward at a slow pace. The current maximum speed is 27 inches per second (0.7m/s).

NIST engineers plan to design the HLPR to autonomously dock with toilets, provide voice-activation capability so patients can call the HLPR from another location, and provide dial-in leg loading to limit leg forces during rehabilitation.

Firefighters sometimes find themselves fighting blazes in temperatures as high as 500 degrees F (260 degrees C). Firefighter gear and self-contained breathing apparatus can allow firefighters to safely work for a limited time during these conditions. A recently released National Institute of Standards and Technology (NIST) study,* however, reveals that first responders can’t rely on their unprotected handheld radios even in routine firefighting situations, much less in higher-temperature fires, where good communications are especially crucial.

The NIST fire engineers tested three representative portable radio models from three different manufacturers in a wind tunnel designed to simulate thermal conditions at three different degrees of intensity that firefighters are equipped to withstand—Thermal Class 1, with a maximum temperature of 212 degrees F (100 degrees C) for 25 minutes; Thermal Class 2, with a maximum temperature of 320 degrees F (160 degrees C) for 15 minutes: and Thermal Class 3, with a maximum temperature of 500 degrees F (260 degrees C) for 5 minutes. Each of the radios tested listed their maximum operating temperatures as only 140 degrees F (60 degrees C).

One radio of the three samples would not transmit or receive after 25 minutes at 212 degrees F though it did begin working after a cooling off period. In another 15-minute experiment at 320 degrees F, one radio went dead within 8.5 minutes. The other two radios suffered significant performance problems from transmission and reception shutdown to signal degradation or fluctuation. None survived the Thermal Class 2 test and cool down period.

Portable radios inside pockets or firefighter turnout gear fared much better. All survived temperature tests at Thermal Class 1 and Thermal Class 2 maximum heats and times. Pocket protected radios also survived Thermal Class 3, but exposed cords, speakers and microphones did not, effectively limiting the radios to Thermal Class 2 electronics. The NIST engineers suggest that small design changes on the speaker/microphones and cords could allow all the protected radios to reach a Thermal Class 3 rating.

NIST conducted the study to evaluate the general performance of portable radios at elevated thermal conditions, to identify shortcomings and to suggest standards for the radios. The results will be used to develop test methods and recommendations that will be submitted to the National Fire Protection Association and other appropriate standards-setting bodies. The NIST study was conducted by the Building and Fire Research Laboratory for the NIST Office of Law Enforcement Standards with funds from the Department of Homeland Security.

A gyromagnetic effect discovered by Albert Einstein and Dutch physicist Wander Johannes de Haas—the rotation of an object caused by a change in magnetization—has been measured at micrometer-scale dimensions for the first time at the National Institute of Standards and Technology (NIST). The new method may be useful in the development and optimization of thin film materials for read heads, memories and recording media for magnetic data storage and spintronics, an emerging technology that relies on the spin of electrons instead of their charge as in conventional electronics.

The Einstein-de Haas effect was first observed in experiments reported in 1915, in which a large iron cylinder suspended by a glass wire was made to rotate by an alternating magnetic field applied along the cylinder’s central axis. By contrast, the NIST experiments, described in the Sept. 18 issue of Applied Physics Letters,* measured the Einstein-de Haas effect in a ferromagnetic thin film only 50 nanometers thick deposited on a microcantilever—a tiny beam anchored at one end and projecting into the air. An alternating magnetic field induced changes in the magnetic state of the thin film, and the resulting torque bent the cantilever up and down by just a few nanometers.

Using a laser interferometer to measure the movements of the cantilever and comparing those data to changes in the magnetic state of the material, researchers were able to determine the “magnetomechanical ratio,” or the extent to which the material twists in response to changes in its magnetic state. The magnetomechanical ratio is related to another important parameter, the “g-factor,” a measure of the internal magnetic rotation of the electrons in a material in a magnetic field.

The magnetomechanical ratio and the g-factor are critical in understanding magnetization dynamics and designing magnetic materials for data storage and spintronics applications, but they are extremely difficult to determine accurately because of many potential complicating effects. The NIST experiments provide a proof-of-concept for using the Einstein-de Haas effect to determine the magnetomechanical ratio and the related g-factor in thin ferromagnetic films. The researchers note that a number of improvements are possible, such as operating the cantilever system in a vacuum to reduce the effects of any changes in temperature.

* T.M. Wallis, J. Moreland and P. Kabos. 2006. Einstein-de Haas effect in a NiFe film deposited on a microcantilever. Applied Physics Letters. Sept. 18.

Working under severe time pressure, government laboratories can analyze radioactive samples fairly quickly—in a matter of hours—but with variable accuracy, and sometimes relaxed quality control procedures, according to a published analysis of two federally organized tests of the labs’ emergency preparedness.

The exercises, described in a recent paper,* were organized by the National Institute of Standards and Technology (NIST) and the Environmental Measurements Laboratory (EML), a Department of Homeland Security Science and Technology laboratory. Six laboratories, including federal, state and one foreign organization, participated in the NIST tests, and 17 in the EML tests.

The tests were conducted to let government officials know how quickly data can be obtained from radioactive samples after an accident or attack, and how accurate the results are likely to be, as well as to identify opportunities for improvement. Decisions concerning the protection of emergency workers and public health, as well as the provision of food, shelter and medical care, may depend on timely, reliable data.

The tests evaluated measurement capability and capacity, effect of time spent counting radioactivity, measurement accuracy and confidence, and operational issues. The NIST and EML tests involved different types of samples and analyses, but the results were consistent: The average measurement across all matrices and measurement types was within about 30 percent of the expected value. (This compares to 2-4 percent in the regular NIST Radiochemistry Intercomparison Program, which has a 60-day turnaround time.) Some laboratories, in order to respond quickly, had to modify standard operating procedures, reducing quality control over the data. In addition, some labs underestimated the precision of their measurements, while others overestimated it. As experience is acquired in future exercises, improvements are expected in the labs’ capabilities.

Considering how to improve response to a radiological emergency, the authors recommended that informational guides on estimating measurement uncertainties be developed, and technical exchange between laboratories be increased; that participation in NIST’s traceable radioassay preparedness exercises be increased; that radiochemical alpha and beta assay capabilities be improved; and that guidelines be developed for decision makers to help them better understand the relevance of measurement uncertainty at various stages of an emergency response.

* K.G.W. Inn, L. Outola, S. Nour, H. Kurosaki, L. Albin, and A. Berne. Radioanalytical emergency response exercise. Journal of Radioanalytical and Nuclear Chemistry. August 2006.

Using an innovative sensor for detecting single photons, scientists from Los Alamos National Laboratory (LANL), the National Institute of Standards and Technology (NIST) and Albion College (Albion, Mich.) have set two significant distance records for distributing “keys” (or codes) for quantum encryption, the most secure method known for protecting the privacy of information.*

Quantum key distribution (QKD) systems represent cryptographic keys as sequences of single photons transmitted with their electric fields in different quantum states to represent the binary values 1 and 0. The laws of quantum physics dictate that a photon cannot be intercepted without changing its quantum state, revealing the eavesdropper. Properly designed, a QKD system is “unbreakable.” One practical weakness is the current lack of reliable commercial single-photon sources. Very weak laser pulses are used instead, and they often produce more than one photon per pulse, all with the same orientation. One of these duplicate photons could be intercepted and read undetected.

The LANL/NIST team used careful laser adjustments and a special NIST-designed photon detector to generate and transmit secret quantum keys over 184.6 kilometers (km) of fiber-optic cable, the longest distance ever recorded for QKD. The previous record was 122 km. The technique used for the 184.6 km is secure against “reasonable attacks,” because the laser adjustments used have only a moderate probability of generating more than one photon per pulse. The team also used slightly different adjustments to set other QKD distance records, including absolutely secure transmission of secret keys over 67.5 km, surpassing the previous record of 50.6 km.

The work was funded in part by the Director of Central Intelligence postdoctoral program, Defense Advanced Research Projects Agency and the National Security Agency/Disruptive Technology Office.

Airborne contaminants in homes can range from allergic agents such as mold to potentially lethal threats such as carbon monoxide. Engineers at the National Institute of Standards and Technology (NIST) have developed a database of U.S. residential housing* to help conduct nationwide analyses of ventilation, air cleaning or moisture control strategies to reduce indoor air pollution.

Most people presume that the indoor air quality (IAQ) measures that rid one house of airborne contaminants should work in a similar house, but when it comes to ranking, on a regional or national scale, potentially expensive residential code or construction changes, housing and health authorities as well as homebuilders want more than conventional wisdom and supposition. They want data, and a lot of it. The new NIST set of more than 200 residential dwellings, representing 80 percent of the United States housing stock, can be combined with a computer simulation technique to determine the impacts of IAQ interventions.

NIST developed its database of model homes from the U.S. Census Bureau’s American Housing Survey (AHS) and the U.S. Department of Energy’s (DOE) Residential Energy Consumption Survey (RSECS). They then selected 209 dwellings as representative of 80 percent of U.S. housing stock. The homes, grouped into four categories—detached, attached, manufactured homes and apartments, were defined by their age, floor area, number of floors, foundation type and existence of a garage.

The engineers then developed floor plans for each house and created a model of each in NIST’s multizone indoor air quality and ventilation assessment computer program, CONTAM. Analysts can use the models to simulate and examine energy, IAQ and human exposure issues in a particular type of dwelling or all the dwellings as a group. Conclusions drawn from simulations with a particular house type should be valid for similar houses on a nationwide or regional level. The current multizone representations of the 209 dwellings created with CONTAM are available at www.bfrl.nist.gov/IAQanalysis along with floorplans of the buildings. The U.S. Department of Housing and Urban Development sponsored this work.

Dr. William D. Phillips, the first researcher from the National Institute of Standards and Technology (NIST) to become a Nobel Laureate, has been awarded the 2006 Career Achievement Medal in the Service to America Medals program. The 2006 award winners were announced on September 27.

Phillips was cited for having “launched an entirely new subfield of atomic, molecular and optical physics,” as well as being the first federal employee to win the Nobel Prize for Physics for work done as part of his official duties. Phillips shared the 1997 Nobel Prize in physics for his research using laser light to cool and trap atoms for precision spectroscopy and quantum physics experiments.

The Service to America Medals program is conducted by three magazines, Government Executive, the National Journal and The Atlantic, in association with the Partnership for Public Service. Read more at http://www.govexec.com/story_page.cfm?articleid=35135&dcn=e_gvet

On Sept. 26, 2006, the National Institute of Standards and Technology (NIST) released three draft information technology security publications for public comment:

The complete text and brief summaries of the publications, along with the deadlines for submitting public comments for each, may be found on the Computer Security Resource Center (CSRC) draft publications page at http://csrc.nist.gov/publications/drafts.html.

The American National Standards Institute (ANSI) and the National Institute of Standards and Technology (NIST), in cooperation with the Standardization Administration of China (SAC), have launched a “Standards Portal" that will facilitate the trade of goods and services between the United States and the People’s Republic of China.

Standardization issues rank sixth among the top 10 concerns of U.S. companies doing business in China, because compliance with standards can be a prerequisite for gaining access to foreign markets. The Standards Portal contains dual-language (Mandarin and English) educational materials on the structure, history and operation of the United States and Chinese standards systems; a database of 2,000 standards (1,000 from each nation) considered vital to successful trade between the two nations; and access to nearly 300,000 other national, regional and international standards and guidelines.

New NIST research reinforcing the theory that faulty rivets caused the rapid demise of the luxury liner RMS Titanic will be featured in Seconds from Disaster: Sinking of the Titanic, premiering on the National Geographic Channel on Wednesday, Oct. 4, 2006. Unable to withstand stresses due to the Titanic’s collision with an iceberg in 1912, substandard rivets broke more readily and large sections of the hull separated along riveted seams. As a result, the Titanic could not stay afloat long enough for a nearby ship to arrive and assist the more than 1,500 people stranded on board. The show focuses largely on the results of research conducted by NIST metallurgist Tim Foecke and his past doctoral student Jennifer Hooper McCarty, who also uncovered supporting evidence in searches of government and shipbuilder records. Program schedules can be found on the Seconds from Disaster Web site.

Starting Oct. 16, teams of business, education and health care experts will visit 13 organizations—one service company, three small businesses, three education organizations and six health care organizations—as the final review stage for the 2006 Malcolm Baldrige National Quality Award. As part of a pilot program, two non-profit organizations also will be visited, but they will not be eligible to receive the award this year. Baldrige award recipients for 2006 are expected to be announced in late November. For more information on the Baldrige National Quality Program, see http://baldrige.nist.gov.

(Return to NIST News Page)

Editor: Michael Baum

Date created: 9/27/06
Date updated: 9/28/06
Contact: inquiries@nist.gov