2,354 research outputs found
Development and application of rice starch based edible coating to improve the postharvest storage potential and quality of plum fruit (<i>Prunus salicina</i>)
The study investigated the possibility of enhancing the shelf life of plum fruit coated with rice starch-ι-carrageenan (RS-ι-car) composite coating blended with sucrose fatty acid esters (FAEs). Film solution (starch 3%, carrageenan 1.5% and FAEs 2%) was prepared by mixing the ingredients and properties of stand-alone films (physical, mechanical, barrier and surface morphology) were studied before applying the coating on fruit surface. Fruit were stored at 20 °C for 3 weeks and analyzed for weight loss, ethylene production, respiration rate, color change, firmness, and titratable acidity (TA) and soluble solid content (SSC). Surface morphology of stand-alone film and fruit surface (after applying on the plum fruit) was studied using scanning electron microscopy (SEM). Phytochemical analysis was performed during the storage period and total phenolic content (TPC), total antioxidant capacity (TAC), flavonoid content (FC) and free radical scavenging activity were determined. The rice starch composite coating was shown to be effective in reducing both weight loss (WL) and respiration rate and inhibiting the endogenous ethylene production when compared to the uncoated control fruit stored at room temperature (p < 0.05). TPC, TAC, FC and free radical scavenging activity was unaffected in the coated fruit throughout the storage period (p < 0.05). The findings reported in this study indicate that the RS-ι-car-FAEs coating prolongs the shelf life and maintains the overall quality of plum fruit during storage and could potentially be commercialized as a new edible coating for the plum fruit industry
Fifty years of spellchecking
A short history of spellchecking from the late 1950s to the present day, describing its development through dictionary lookup, affix stripping, correction, confusion sets, and edit distance to the use of gigantic databases
UK Large-scale Wind Power Programme from 1970 to 1990: the Carmarthen Bay experiments and the Musgrove Vertical-Axis Turbines
This article describes the development of the Musgrove Vertical Axis Wind Turbine (VAWT)
concept, the UK ‘Carmarthen Bay’ wind turbine test programme, and UK government’s wind
power programme to 1990. One of the most significant developments in the story of British
wind power occurred during the 1970s, 1980s, and 1990s, with the development of the
Musgrove vertical axis wind turbine and its inclusion within the UK Government’s wind
turbine test programme. Evolving from a supervisor’s idea for an undergraduate project at
Reading University, the Musgrove VAWT was once seen as an able competitor to the
horizontal axis wind systems that were also being encouraged at the time by both the UK
government and the Central Electricity Generating Board, the then nationalised electricity
utility for England and Wales. During the 1980s and 1990s the most developed Musgrove
VAWT system, along with three other commercial turbine designs was tested at
Carmarthen Bay, South Wales as part of a national wind power test programme. From these
developmental tests, operational data was collected and lessons learnt, which were
incorporated into subsequent wind power operations.http://dx.doi.org/10.1260/03095240677860621
Evidence of Electromagnetic Absorption by Collective Modes in the Heavy Fermion Superconductor UBe13
We present results of a microwave surface impedance study of the heavy
fermion superconductor UBe13. We clearly observe an absorption peak whose
frequency- and temperature-dependence scales with the BCS gap function.
Resonant absorption into a collective mode, with energy approximately
proportional to the superconducting gap, is proposed as a possible
explantation
Frequency Characteristics of Visually Induced Motion Sickness
This article was published in the journal, Human Factors [Sage Publications / © Human Factors and Ergonomics Society.]. The definitive version is available at: http://dx.doi.org/10.1177/0018720812469046Objective: The aim of this study was to explore
the frequency response of visually induced motion
sickness (VIMS) for oscillating linear motion in the foreand-
aft axis.
Background: Simulators, virtual environments,
and commercially available video games that create an
illusion of self-motion are often reported to induce
the symptoms seen in response to true motion. Often
this human response can be the limiting factor in the
acceptability and usability of such systems. Whereas
motion sickness in physically moving environments
is known to peak at an oscillation frequency around
0.2 Hz, it has recently been suggested that VIMS peaks
at around 0.06 Hz following the proposal that the
summed response of the visual and vestibular selfmotion
systems is maximized at this frequency. Methods: We exposed 24 participants to random
dot optical flow patterns simulating oscillating foreand-
aft motion within the frequency range of 0.025 to
1.6 Hz. Before and after each 20-min exposure, VIMS was
assessed with the Simulator Sickness Questionnaire.
Also, a standard motion sickness scale was used to rate
symptoms at 1-min intervals during each trial.
Results: VIMS peaked between 0.2 and 0.4 Hz with
a reducing effect at lower and higher frequencies.
Conclusion: The numerical prediction of the
“crossover frequency” hypothesis, and the design
guidance curve previously proposed, cannot be accepted
when the symptoms are purely visually induced.
Application: In conditions in which stationary
observers are exposed to optical flow that simulates
oscillating fore-and-aft motion, frequencies around 0.2
to 0.4 Hz should be avoided
Dynamical simulation of current fluctuations in a dissipative two-state system
Current fluctuations in a dissipative two-state system have been studied
using a novel quantum dynamics simulation method. After a transformation of the
path integrals, the tunneling dynamics is computed by deterministic integration
over the real-time paths under the influence of colored noise. The nature of
the transition from coherent to incoherent dynamics at low temperatures is
re-examined.Comment: 4 pages, 4 figures; to appear in Phys. Rev. Letter
Scaling and crossovers in activated escape near a bifurcation point
Near a bifurcation point a system experiences critical slowing down. This
leads to scaling behavior of fluctuations. We find that a periodically driven
system may display three scaling regimes and scaling crossovers near a
saddle-node bifurcation where a metastable state disappears. The rate of
activated escape scales with the driving field amplitude as , where is the bifurcational value of . With
increasing field frequency the critical exponent changes from
for stationary systems to a dynamical value and then again to
. The analytical results are in agreement with the results of
asymptotic calculations in the scaling region. Numerical calculations and
simulations for a model system support the theory.Comment: 18 page
Luminous Infrared Galaxies with the Submillimeter Array: I. Survey Overview and the Central Gas to Dust Ratio
We present new data obtained with the Submillimeter Array for a sample of
fourteen nearby luminous and ultraluminous infrared galaxies. The galaxies were
selected to have luminosity distances D < 200 Mpc and far-infrared luminosities
log(L_FIR) > 11.4. The galaxies were observed with spatial resolutions of order
1 kpc in the CO J=3-2, CO J=2-1, 13CO J=2-1, and HCO+ J=4-3 lines as well as
the continuum at 880 microns and 1.3 mm. We have combined our CO and continuum
data to measure an average gas-to-dust mass ratio of 120 +/- 28 (rms deviation
109) in the central regions of these galaxies, very similar to the value of 150
determined for the Milky Way. This similarity is interesting given the more
intense heating from the starburst and possibly accretion activity in the
luminous infrared galaxies compared to the Milky Way. We find that the peak H_2
surface density correlates with the far-infrared luminosity, which suggests
that galaxies with higher gas surface densities inside the central kiloparsec
have a higher star formation rate. The lack of a significant correlation
between total H_2 mass and far-infrared luminosity in our sample suggests that
the increased star formation rate is due to the increased availability of
molecular gas as fuel for star formation in the central regions. In contrast to
previous analyses by other authors, we do not find a significant correlation
between central gas surface density and the star formation efficiency, as trace
by the ratio of far-infrared luminosity to nuclear gas mass. Our data show that
it is the star formation rate, not the star formation efficiency, that
increases with increasing central gas surface density in these galaxies.Comment: 66 pages, 39 figures, aastex preprint format; to be published in ApJ
Supplements. Version of paper with full resolution figures available at
http://www.physics.mcmaster.ca/~wilson/www_xfer/ULIRGS_publi
Atomic Tunneling from a STM/AFM tip: Dissipative Quantum Effects from Phonons
We study the effects of phonons on the tunneling of an atom between two
surfaces. In contrast to an atom tunneling in the bulk, the phonons couple very
strongly, and qualitatively change the tunneling behavior. This is the first
example of {\it ohmic} coupling from phonons for a two-state system. We propose
an experiment in which an atom tunnels from the tip of an STM, and show how its
behavior would be similar to the Macroscopic Quantum Coherence behavior
predicted for SQUIDS. The ability to tune and calculate many parameters would
lead to detailed tests of the standard theories. (For a general intro to this
work on the on the World-Wide-Web: http://www.lassp.cornell.edu. Click on
``Entertaining Science Done Here'' and ``Quantum Tunneling of Atoms'')Comment: 12 pages, ReVTex3.0, two figures (postscript). This is a
(substantially) revised version of cond-mat/9406043. More info (+ postscript
text) at : http://www.lassp.cornell.edu/ardlouis/publications.htm
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