Penn State Intercom......June
'Smart meter' knows when
has reached the proper solidity
By Vicki Fong
engineers have developed a "smart" maturity meter to estimate and to signal
by phone when newly poured concrete bridge supports, pavements and highway
surfaces have reached the correct hardness and strength to be opened to
traffic or the next phase of construction.
of estimating the strength of concrete can save taxpayer money in reduced
cost of quality control and assurance testing," said Paul Tikalsky, associate
professor of civil and environmental engineering and a developer of the
prototype. "In addition, the meter provides information on the status
of the actual structure rather than on representative concrete samples,
the method most often used today to estimate concrete strength."
and accessory technology were developed by Tikalsky and David G. Tepke
as part of Tepke's master's degree research. Tepke completed his master's
degree program in December and is now a doctoral candidate at the University.
The new maturity
meter is the result of integrating digital phone technology with an existing
concrete monitoring concept. The concept, Tikalsky said, has been around
since the 1940s but has only recently been employed in meters on the commercial
market. The Penn State prototype is a "next generation" meter that the
developers estimate will cost less than those currently available. In
addition, the meter provides real time evaluation and quality control
information with cellular technology.
the heat generated by the chemical reactions in the curing process itself
and the variability in the concrete mixture, as well as other factors,
influence the rate at which concrete structures achieve their intended
strength. When concrete is poured to create a structure, small sample
castings are made, for test purposes, to represent how the concrete is
in the actual structure.
uses the fact that the internal temperature of the concrete can be directly
related to the time it takes to mature. Only a minimal number of castings
need to be made for the method to be effective. To determine the internal
temperature, the prototype uses simple thermocouple technology and then
integrates it with a computer program-net-on-a-microchip, along with cell
phone technology, to provide a "smart" monitoring component.
In the prototype,
sensor wires are snaked through the concrete forms before the cement is
poured. After the cement is in place, the wires are connected to the maturity
meter which is, in turn, connected to a digital cell phone. By calling
up the phone, the developers can download the data and use software they
have developed to convert the temperature data into a maturity rating.
The meter is
expected to cost about $2,000 when it is commercially available and to
reduce substantially the test castings that need to be made. Since an
average of 200 castings are required for each concrete bridge upright,
for example, the potential savings represents a significant part of the
quality control and assurance testing budget.
Vicki Fong can be
reached at VFong@psu.edu.
Computer model predicts
outcome of DNA shuffling
By A'ndrea Messer
Industries using DNA
shuffling to improve enzymes, therapeutic proteins, vaccines and viral
vectors may soon have a computational method for predicting the number
and likely locations of crossovers, according to a research team.
"To date, the
application of these methods has been based on experience and empirical
methods and there was no model to understand the process which can be
time consuming, expensive and of uncertain outcome," said Costas D. Maranas,
assistant professor of chemical engineering. "We used thermodynamics and
reaction engineering to evaluate and model this complex reaction network
so we can now predict where the DNA from different parent genes will recombine."
uses related genes from different species or genes with related function,
fragments them and reassembles then through recombination. Researchers
then place recombined genes into Escherichia coli to identify which
new genes produce usable or potentially interesting products. Those genes
that express a potentially interesting protein or enzyme are again fragmented
and reassembled to form new recombinant genes. The process continues until
a protein with the desired qualities is found.
program was developed by Maranas; Gregory L. Moore, graduate student in
chemical engineering; Stefan Lutz, postdoctoral fellow in chemistry; and
Stephen J. Benkovic, Evan Pugh professor of chemistry and holder of the
Eberly Chair in Chemistry.
model, which provides a predictive framework for DNA shuffling, looked
into how fragment length, annealing temperature, sequence identity and
the number of shuffled parent sequences affect the number, type and distribution
of crossovers along the length of reassembled sequences.
A'ndrea Messer can
be reached at firstname.lastname@example.org.
discovery of 2
most distant objects in the universe
The discovery of the
two most distant objects ever observed in the universe was announced earlier
this month by Donald Schneider, professor of astronomy and astrophysics
and chair of the Sloan Digital Sky Survey Quasar Science Group, at a press
conference during the American Astronomical Society meeting in Pasadena,
"We are trying
to learn how early in the history of the universe the first stars and
galaxies formed," Schneider said.
"This is the
first time any object has been detected beyond redshift 6, which is about
800 million years after the Big Bang," Schneider explained. "One of them
is probably a black hole about 1 million times the mass of our sun, so
models of the formation of our universe now will have to explain how such
an object could have formed so early," he added.
has held many previous records for the discovery of "most distant" quasars,
has been the organizer of the Sloan Digital Sky Survey's quasar science
group since its inception in the early 1990s, helping to assure that its
scientists achieve the projects research goals for quasars, the most luminous
objects in the universe. His announcement is part of the first public
release of data from the Sloan Digital Sky Survey, a large international
the observation of two quasars with respective redshifts of 6.0 and 6.2.
The redshift of an object directly indicates the relative size of the
universe when the light was emitted: light from a redshift 6.2 quasar
left that object when the universe was 7.2 times smaller than it is today.
The two new quasars break the previous distance record established by
last year's SDSS discovery of a quasar at redshift 5.8. The data he presented
also reveal still another quasar of redshift 5.8.
"Quasars are precocious
galaxies whose massive black holes began accreting matter, lighting them
up when the universe was less than 800 million years old," said Xiaohui
Fan of the Institute for Advanced Study in Princeton, N.J., who led the
team within the Quasar Science Group that identified the quasars. "They
allow us to study the birth of galaxies, and the first supermassive black