1,247 research outputs found
Numerische Berechnung von Wirbelstromproblemen mit der Cell-Methode
In dieser Arbeit wird die Cell-Methode auf die quasistatischen Maxwellgleichungen angewendet. Dabei werden für die notwendige Transformation vom Primärgitter auf das duale Gitter reziproke Basisvektoren verwendet. Anhand der Felddiffusion der magnetischen Induktion in einen zylindrischen Leiter werden Ergebnisse der Cell-Methode mit einer analytischen Vergleichsrechnung präsentiert
In-flight calibration of STEREO-B/WAVES antenna system
The STEREO/WAVES (SWAVES) experiment on board the two STEREO spacecraft
(Solar Terrestrial Relations Observatory) launched on 25 October 2006 is
dedicated to the measurement of the radio spectrum at frequencies between a few
kilohertz and 16 MHz. The SWAVES antenna system consists of 6 m long orthogonal
monopoles designed to measure the electric component of the radio waves. With
this configuration direction finding of radio sources and polarimetry (analysis
of the polarization state) of incident radio waves is possible. For the
evaluation of the SWAVES data the receiving properties of the antennas,
distorted by the radiation coupling with the spacecraft body and other onboard
devices, have to be known accurately. In the present context, these properties
are described by the antenna effective length vectors. We present the results
of an in-flight calibration of the SWAVES antennas using the observations of
the nonthermal terrestrial auroral kilometric radiation (AKR) during STEREO
roll maneuvers in an early stage of the mission. A least squares method
combined with a genetic algorithm was applied to find the effective length
vectors of the STEREO Behind (STEREO-B)/WAVES antennas in a quasi-static
frequency range () which fit best to the model
and observed AKR intensity profiles. The obtained results confirm the former
SWAVES antenna analysis by rheometry and numerical simulations. A final set of
antenna parameters is recommended as a basis for evaluations of the SWAVES
data
College students’ perceptions regarding sensory aspects of conventionally produced and unconventionally produced foods: implications for marketing to the Millennial generation
Consumers vote every day on which products line the shelves of grocery stores, co-ops, and niche markets. Public unrest with regard to the environmental, animal welfare, food purity, and human health impacts of agricultural production practices have led to the rise of unconventionally produced (UP) food products. While the sales of UP foods is increasing, studies regarding the qualities of such products that impact consumer purchases have yielded inconsistent results. This study examined students’ perceptions of sensory aspects of conventionally produced (CP) and UP foods to better understand how sensory aspects impact decisions to purchase. Students reported consistent perceptions regarding the favorability of each sensory aspect of chicken and apples; the UP versions of the products yielded higher mean scores on every sensory aspect. However, students’ perceptions of the sensory qualities of chocolate, milk, and beef were not consistent; for example, they reported more favorable perceptions of the appearance and smell of CP milk, but perceived a more favorable texture and flavor from the UP milk. The results of this study imply that when making purchasing decisions, consumers may value specific sensory attributes over others. One approach to marketing UP products is to focus on valued extrinsic aspects designed to attract consumers to purchase products even though they may have less favorable perceptions of certain sensory qualities
College Students\u27 Perceptions regarding Sensory Aspects of Conventionally Produced and Unconventionally Produced Foods: Implications for Marketing to the Millennial Generation
Every day consumers vote which products line the shelves of grocery stores, co-ops, and niche markets by use of their dollars. Public unrest with regard to the environment, animal welfare, food purity, and human health impacts of agricultural production practices have led to the rise of alternatively produced food products. While the sales of alternatively produced foods are increasing, studies regarding the qualities of such products impact consumer purchases have yielded inconsistent results. This study examined students’ perceptions of sensory aspects of conventionally produced and alternatively produced foods to better understand how sensory aspects impact decisions to purchase. Students reported consistent perceptions regarding the favorability of each sensory aspect of chicken and apples; the alternatively produced versions of the products yielded higher mean scores on every sensory aspect. However, students’ perceptions of the sensory qualities of chocolate, milk, and beef were not consistent; for example, they reported more favorable perceptions of the appearance and smell of conventionally produced milk, but perceived a more favorable texture and flavor from the alternatively produced milk. The results of this study imply when making purchasing decisions, consumers may value specific sensory attributes over others. An alternative approach to marketing alternatively produced products is to focus on valued extrinsic aspects designed to attract consumers to purchase products in spite of their perhaps less valued perceptions of sensory aspects
A Blind Search for Magnetospheric Emissions from Planetary Companions to Nearby Solar-type Stars
This paper reports a blind search for magnetospheric emissions from planets
around nearby stars. Young stars are likely to have much stronger stellar winds
than the Sun, and because planetary magnetospheric emissions are powered by
stellar winds, stronger stellar winds may enhance the radio luminosity of any
orbiting planets. Using various stellar catalogs, we selected nearby stars (<~
30 pc) with relatively young age estimates (< 3 Gyr). We constructed different
samples from the stellar catalogs, finding between 100 and several hundred
stars. We stacked images from the 74-MHz (4-m wavelength) VLA Low-frequency Sky
Survey (VLSS), obtaining 3\sigma limits on planetary emission in the stacked
images of between 10 and 33 mJy. These flux density limits correspond to
average planetary luminosities less than 5--10 x 10^{23} erg/s. Using recent
models for the scaling of stellar wind velocity, density, and magnetic field
with stellar age, we estimate scaling factors for the strength of stellar
winds, relative to the Sun, in our samples. The typical kinetic energy carried
by the stellar winds in our samples is 15--50 times larger than that of the
Sun, and the typical magnetic energy is 5--10 times larger. If we assume that
every star is orbited by a Jupiter-like planet with a luminosity larger than
that of the Jovian decametric radiation by the above factors, our limits on
planetary luminosities from the stacking analysis are likely to be a factor of
10--100 above what would be required to detect the planets in a statistical
sense. Similar statistical analyses with observations by future instruments,
such as the Low Frequency Array (LOFAR) and the Long Wavelength Array (LWA),
offer the promise of improvements by factors of 10--100.Comment: 11 pages; AASTeX; accepted for publication in A
Novel critical point drying (CPD) based preparation and transmission electron microscopy (TEM) imaging of protein specific molecularly imprinted polymers (HydroMIPs)
We report the transmission electron microscopy (TEM) imaging of a hydrogel-based molecularly imprinted polymer (HydroMIP) specific to the template molecule bovine haemoglobin (BHb). A novel critical point drying based sample preparation technique was employed to prepare the molecularly imprinted polymer (MIP) samples in a manner that would facilitate the use of TEM to image the imprinted cavities, and provide an appropriate degree of both magnification and resolution to image polymer architecture in the <10 nm range. For the first time, polymer structure has been detailed that clearly displays molecularly imprinted cavities, ranging from 5-50 nm in size, that correlate (in terms of size) with the protein molecule employed as the imprinting template. The modified critical point drying sample preparation technique used may potentially play a key role in the imaging of all molecularly imprinted polymers, particularly those prepared in the aqueous phase
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