1,647 research outputs found
Perspectives on Children in Maine’s Canning Industry, 1907-1911
This article discusses the role of young children in the canning and preserving of local fruits, vegetables, and shellfish in Maine during the latter part of the nineteenth century
Can negative electricity prices encourage inefficient electrical energy storage devices?
This paper explores whether negative electricity prices can change the rationale that efficient energy storage devices are more economical for arbitrage in electricity markets. An established model algorithm to determine the maximum available arbitrage revenue and optimum schedule of electrical energy storage (EES) operation is used to simulate storage with a time-series of electricity prices which includes some negative prices. Our results suggest that at any likely frequency of negative electricity prices, inefficient EES is not encouraged, and can only be encouraged for EES devices with very low energy capacity to power ratios
JOINT DISPLACEMENTS AND PEAK ACHILLES TENDON FORCE DURING IRISH DANCING-SPECIFIC LANDING TASKS
Achilles tendinopathy is prevalent among Irish dancers, thought to be due to the high impact, stiff-style landing tasks associated with the sport. This study aimed to investigate the relationship between sagittal plane joint displacements, at the ankle, knee, hip and thorax segment, and peak Achilles tendon force during an Irish dancing ‘leap over’ landing task. Kinetic and kinematic data were collected for 12 participants performing the ‘leap over’, and used to calculate peak Achilles tendon force and joint displacements. Results of the study found a statistically significant positive correlation between ankle dorsiflexion and peak Achilles tendon force during the ‘leap over’. These findings can be used to inform future research into the effect of joint displacement on peak Achilles tendon force, and to develop strategies to help dancers reduce their risk of developing Achilles tendinopathy
Modeling Soil Water Contents and Their Effects on Stream Flow in Kentucky
Soil water contents of eight important soil series in Kentucky were measured periodically during the summer growing season for four years, 1977 through 1980. The soils divided into three groups according to their behavior. The first group (Maury and Crider) is well-drained and never showed excess water above field capacity at any time during the four seasons. The second group (Zanesville, Lowell, Calloway, Grenada and Shelbyville) showed perched water tables at times, especially during the early part of the growing season. The third group was represented by the Huntington soil which has a permanent water table.
The in-situ field capacity or upper limits was determined on numerous samples of the Maury, Crider and Shelbyville soil series. Variation within series was rather low, indicating that samples taken at one site are representative of the soil in general.
A model for estimating the soil water in each 15 cm layer was developed and proved to work very well with both Maury and Crider soils. Lowell soil was predicted poorly by the model, with other soils being intermediate. A variation of the model which assumed that the lowest layer of the Huntington was always at the upper limit due to a permanent water table also worked well.
The water calculated from the model as deep drainage was used as a measure of increase in streamflow and compared to measured streamflow on three watersheds and four soils in 1978 and 1979. The R2 values ranged from 0.41 to 0.95 and the slope, which ideally should be 1.0, ranged from 0.54 to 1.36. The quantitative measure of streamflow was not satisfactory but the prediction of events was quite good. Modifications in the model that seem to be required include provisions for evaporation from foliage with small rains, higher evapotranspiration at lower soil water contents, less deep drainage with small rains and an aquifer storage factor
Networked Assembly of Affine Physical System Models
Engineering design is evolving into a global strategy that distributes engineering effort to team members around the world. Because modern engineering design uses analytical models, model information mus
Pacemaker-induced cardiomyopathy in the sheep: RVA but not RVOT pacing results in a heart failure cellular phenotype
Method of Collective Degrees of Freedom in Spin Coherent State Path Integral
We present a detailed field theoretic description of those collective degrees
of freedom (CDF) which are relevant to study macroscopic quantum dynamics of a
quasi-one-dimensional ferromagnetic domain wall. We apply spin coherent state
path integral (SCSPI) in the proper discrete time formalism (a) to extract the
relevant CDF's, namely, the center position and the chirality of the domain
wall, which originate from the translation and the rotation invariances of the
system in question, and (b) to derive effective action for the CDF's by
elimination of environmental zero-modes with the help of the {\it Faddeev-Popov
technique}. The resulting effective action turns out to be such that both the
center position and the chirality can be formally described by boson coherent
state path integral. However, this is only formal; there is a subtle departure
from the latter.Comment: 10 pages, 1 figur
Memetic Multilevel Hypergraph Partitioning
Hypergraph partitioning has a wide range of important applications such as
VLSI design or scientific computing. With focus on solution quality, we develop
the first multilevel memetic algorithm to tackle the problem. Key components of
our contribution are new effective multilevel recombination and mutation
operations that provide a large amount of diversity. We perform a wide range of
experiments on a benchmark set containing instances from application areas such
VLSI, SAT solving, social networks, and scientific computing. Compared to the
state-of-the-art hypergraph partitioning tools hMetis, PaToH, and KaHyPar, our
new algorithm computes the best result on almost all instances
Coherent States with SU(N) Charges
We define coherent states carrying SU(N) charges by exploiting generalized
Schwinger boson representation of SU(N) Lie algebra. These coherent states are
defined on complex planes. They satisfy continuity property
and provide resolution of identity. We also exploit this technique to construct
the corresponding non-linear SU(N) coherent states.Comment: 18 pages, LaTex, no figure
Laser Doppler Electrophoresis and electro-osmotic flow mapping: A novel methodology for the determination of membrane surface zeta potential
A novel technique employing an Uzigirs dip cell arrangement is used in conjunction with Laser Doppler Electrophoresis for the determination of the surface zeta potential for a UF, NF, and RO membrane. To the authors best knowledge this is the first study employing Laser Doppler Electrophoresis and Electro-osmotic Flow Mapping for membrane surface charge determination. High correlation of the regression fit (R2>0.95) for a carboxylated polystyrene latex particle electrophoretic mobility was achieved at low electrolyte concentrations (1mM and 10mM NaCl), but the reliability and accuracy of the extrapolated zeta potential values were problematic at higher concentration due to high measurement uncertainty (>10% in some cases). Changes in the applied electric field increased the phase resolution of 50mM NaCl electrolyte solutions between 0.5-2.0V. However, the effects of Joule heating at higher voltages compromised 50mM NaCl sample integrity. When compared with the established Tangential Streaming Potential method, Laser Doppler Electrophoresis measurements provided similar zeta potential values and trends indicating that this new methodology can indeed be employed for membrane characterization purposes; however, further research needs to be conducted in order to optimize this new technique and set appropriate operating limits
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