2,314 research outputs found
Charge Transport in Bifidobacterium animalis subsp. lactis BB-12 under the various Atmosphere
The influence of relative humidity (RH) on quasistatic current-voltage
characteristics of Bifidobacterium animalis subsp. lactis BB-12 thin
layers have been studied for the first time. The value of electrical
conductivity in 75 RH was found to be in the order of 10 (ohm
cm) which was 10 orders of magnitude higher than that observed in
dry atmosphere. Here we also demonstrated that RH played a key role in
hysteresis behaviour of the measured characteristics. FTIR
measurements showed that under water moisture environment the associated bonds
for amine and carboxyl group were greatly strengthened that was the source of
number of free charge carries after ionization. The type of surface charge of
Bifidobacterium animalis subsp. lactis BB-12 was found to be negative by zeta
potential measurements, claiming that electrons were the charge carriers.Comment: 6 pages, 6 figure
High Power CMUTs: Design and experimental verification
Cataloged from PDF version of article.Capacitive micromachined ultrasonic transducers
(CMUTs) have great potential to compete with piezoelectric
transducers in high-power applications. As the output pressures
increase, nonlinearity of CMUT must be reconsidered
and optimization is required to reduce harmonic distortions.
In this paper, we describe a design approach in which uncollapsed
CMUT array elements are sized so as to operate at the
maximum radiation impedance and have gap heights such that
the generated electrostatic force can sustain a plate displacement
with full swing at the given drive amplitude. The proposed
design enables high output pressures and low harmonic
distortions at the output. An equivalent circuit model of the
array is used that accurately simulates the uncollapsed mode
of operation. The model facilities the design of CMUT parameters
for high-pressure output, without the intensive need
for computationally involved FEM tools. The optimized design
requires a relatively thick plate compared with a conventional
CMUT plate. Thus, we used a silicon wafer as the CMUT
plate. The fabrication process involves an anodic bonding process
for bonding the silicon plate with the glass substrate. To
eliminate the bias voltage, which may cause charging problems,
the CMUT array is driven with large continuous wave
signals at half of the resonant frequency. The fabricated arrays
are tested in an oil tank by applying a 125-V peak 5-cycle
burst sinusoidal signal at 1.44 MHz. The applied voltage is increased
until the plate is about to touch the bottom electrode
to get the maximum peak displacement. The observed pressure
is about 1.8 MPa with −28 dBc second harmonic at the
surface of the array
SOME ASPECTS OF ENERGY SAVING OF BURDEN MATERIAL IN THE BLAST FURNACE
To determine the possibility of self-stabilization effect for burden
surface texture and gas flow in operating blast furnace under the proper conditions
was experimentally proved for the first time, as well as the reasons of the effect
disruption
Photonuclear reactions with Zinc: A case for clinical linacs
The use of bremsstrahlung photons produced by a linac to induce photonuclear
reactions is wide spread. However, using a clinical linac to produce the
photons is a new concept. We aimed to induce photonuclear reactions on zinc
isotopes and measure the subsequent transition energies and half-lives. For
this purpose, a bremsstrahlung photon beam of 18 MeV endpoint energy produced
by the Philips SLI-25 linac has been used. The subsequent decay has been
measured with a well-shielded single HPGe detector. The results obtained for
transition energies are in good agreement with the literature data and in many
cases surpass these in accuracy. For the half-lives, we are in agreement with
the literature data, but do not achieve their precision. The obtained accuracy
for the transition energies show what is achievable in an experiment such as
ours. We demonstrate the usefulness and benefits of employing clinical linacs
for nuclear physics experiments
Investigation of Natural Effective Gamma Dose Rates case study: Ardabil Province in Iran
Gamma rays pose enough energy to form charged particles and adversely affect human health. Since, the external exposure of human beings to natural environmental gamma radiation normally exceeds that from all man-made sources combined, natural background gamma dose rates and corresponding annual effective doses were determined for selected cities of Ardabil province from 2009 to 2010. Outdoor gamma dose rates were measured using an Ion Chamber Survey Meter in 105 locations in selected districts. Average absorbed dose for Ardabil, Sar-Ein, Germy, Neer, Shourabil Recreational Lake, and Kosar were determined as 265, 219, 344, 233, 352, and 358 nSvh-1, respectively. Although dose rates recorded for Germi and Kosar are comparable with some areas with high natural radiation background, however, the dose rates in other districts are well below the levels reported for such locations. Average annual effective dose due to indoor and outdoor gamma radiation for Ardabil province was estimated to be 1.73 (1.35-2.39) mSv, which is on average 2 times higher than the world population weighted average
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