2,027 research outputs found
Huge Seebeck coefficients in non-aqueous electrolytes
The Seeebeck coefficients of the non-aqueous electrolytes tetrabutylammonium
nitrate, tetraoctylphosphonium bromide and tetradodecylammonium nitrate in
1-octanol, 1-dodecanol and ethylene-glycol are measured in a temperature range
from T=30 to T=45 C. The Seebeck coefficient is generally of the order of a few
hundreds of microvolts per Kelvin for aqueous solution of inorganic ions. Here
we report huge values of 7 mV/K at 0.1M concentration for tetrabutylammonium
nitrate in 1-dodecanol. These striking results open the question of
unexpectedly large kosmotrope or "structure making" effects of
tetraalkylammonium ions on the structure of alcohols.Comment: Submitted to J. Chem. Phy
Spatial organization and evolutional period of the epidemic model using cellular automata
We investigate epidemic models with spatial structure based on the cellular
automata method. The construction of the cellular automata is from the study by
Weimar and Boon about the reaction-diffusion equations [Phys. Rev. E 49, 1749
(1994)]. Our results show that the spatial epidemic models exhibit the
spontaneous formation of irregular spiral waves at large scales within the
domain of chaos. Moreover, the irregular spiral waves grow stably. The system
also shows a spatial period-2 structure at one dimension outside the domain of
chaos. It is interesting that the spatial period-2 structure will break and
transform into a spatial synchronous configuration in the domain of chaos. Our
results confirm that populations embed and disperse more stably in space than
they do in nonspatial counterparts.Comment: 6 papges,5 figures. published in Physics Review
The Crucible, v. 2, no. 1
A scan of the second edition of a student newspaper published by the Literary Fraternity of the Maine State College in 1874. Several advertisements for Orono and Bangor, Maine, businesses are also included.
The first edition of The Crucible, published in August, 1873, is also available through this collection in Digital Commons
Homeownership and effectiveness of the South Africa government housing subsidy scheme
This paper presents findings on the effectiveness of the South Africa government housing subsidy scheme in the delivery of houses to its citizens, thus providing homeownership especially to the low-income group and the disadvantaged poor. The paper also evaluates the usage of the houses by the occupants. The results from the post-occupancy survey of the provided houses revealed that the progressive realization of housing for the low-income and disadvantaged groups is being met as all beneficiaries were South African citizens. The survey also revealed that the beneficiaries living in the subsidized houses were originally allocated the houses by the Gauteng Department of Housing (GDOH), which oversees housing allocation in the province adopted as the site for the study. However, from those originally allocated, it was indicated that some of the beneficiaries were previously living in shacks, while some were homeless (absolute homelessness). Further findings from the survey showed that the original intended use of the houses by the government (private residential use) is what the subsidized houses are being used for as revealed by the respondents. This paper starts with an overview of the literature on this topic and the importance of homeownership, and then presents the results of the analysis and findings of the research. Finally, the paper draws some conclusions and makes recommendations. The originality of this paper is based on the fact that there have been issues surrounding the South Africa government's financial commitment of 5% of its Gross Domestic Product (GDP) is grossly inadequate to overcome its huge housing backlog. Due to the limited study to substantiate if the little devoted GDP is making any impact on the disadvantaged group, the current research contributes to this body of knowledge
Thermodynamic behaviour and structural properties of an aqueous sodium chloride solution upon supercooling
We present the results of a molecular dynamics simulation study of
thermodynamic and structural properties upon supercooling of a low
concentration sodium chloride solution in TIP4P water and the comparison with
the corresponding bulk quantities. We study the isotherms and the isochores for
both the aqueous solution and bulk water. The comparison of the phase diagrams
shows that thermodynamic properties of the solution are not merely shifted with
respect to the bulk. Moreover, from the analysis of the thermodynamic curves,
both the spinodal line and the temperatures of maximum density curve can be
calculated. The spinodal line appears not to be influenced by the presence of
ions at the chosen concentration, while the temperatures of maximum density
curve displays both a mild shift in temperature and a shape modification with
respect to bulk. Signatures of the presence of a liquid-liquid critical point
are found in the aqueous solution. By analysing the water-ion radial
distribution functions of the aqueous solution we observe that upon changing
density, structural modifications appear close to the spinodal. For low
temperatures additional modifications appear also for densities close to that
corresponding to a low density configurational energy minimum.Comment: 10 pages, 13 figures, 2 tables. To be published in J. Chem. Phy
Cannibalism as a life boat mechanism
Under certain conditions a cannibalistic population can survive when food for the adults is too scarce to support a non-cannibalistic population. Cannibalism can have this lifeboat effect if (i) the juveniles feed on a resource inaccessible to the adults; and (ii) the adults are cannibalistic and thus incorporate indirectly the inaccessible resource. Using a simple model we conclude that the mechanism works when, at low population densities, the average yield, in terms of new offspring, due to the energy provided by one cannibalized juvenile is larger than one
Adoption and diffusion of technical capacity-building innovations by small-scale artisanal fishers in Fiji
Adoption of innovations by farmers and fishers can depend on factors specific to both individuals and their social contexts. Research on the adoption and diffusion of innovations promoted through capacity-building training can provide lessons to support the design and implementation of future development programs. We assess the adoption, diffusion, and outcomes of a livelihoods training program focused on improving postharvest handling and processing of sea cucumbers in 29 coastal villages in Fiji. One year after delivery of the training program, we conducted interviews with sea cucumber fishers (n = 278) and commercial processors (n = 12), as well as focus group discussions (n = 27) with women to examine: (1) which modes of training (training video, manual, and workshops) were most useful; (2) individual- and community-scale characteristics related to adoption and knowledge sharing; (3) whether training produced long-term changes in processing methods used by fishers; and (4) perceived barriers to adoption. Among fishers who were exposed to two or more modes of training (n = 97), most (65%) reported the workshop and manual to be equally useful. Knowledge about the improved methods was shared by 71% of trained fishers and occurred more frequently among women (80%) than men (64%). Trained fishers used shorter, less variable first cooking durations than untrained fishers, and differences were significant for two of six sea cucumber species groups. Adoption and knowledge sharing was not significantly related to the multiscale characteristics examined (age, gender, education, resource dependence, village population size, market access). Some fishers could not access salt for processing, and others were constrained by patron-client relationships. Our study shows that technical capacity-building can benefit from complementary training modes, however other constraints on adoption (e.g., access to materials, patron-client relationships) may need to be addressed to achieve the full benefits of training programs
Cracking stability in tapered DCB test pieces
Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/42750/1/10704_2004_Article_BF00113939.pd
Modified two-potential approach to tunneling problems
One-body quantum tunneling to continuum is treated via the two-potential
approach, dividing the tunneling potential into external and internal parts. We
show that corrections to this approach can be minimized by taking the
separation radius inside the interval determined by simple expressions. The
resulting two-potential approach reproduces the resonance energy and its width,
both for narrow and wide resonances. We also demonstrate that, without losing
its accuracy, the two-potential approach can be modified to a form resembling
the R-matrix theory, yet without any uncertainties of the latter related to the
choice of the matching radius.Comment: 7 two-column pages, 3 figures, extra-explanation added, Phys. Rev. A,
in pres
Spatiotemporal complexity of a ratio-dependent predator-prey system
In this paper, we investigate the emergence of a ratio-dependent
predator-prey system with Michaelis-Menten-type functional response and
reaction-diffusion. We derive the conditions for Hopf, Turing and Wave
bifurcation on a spatial domain. Furthermore, we present a theoretical analysis
of evolutionary processes that involves organisms distribution and their
interaction of spatially distributed population with local diffusion. The
results of numerical simulations reveal that the typical dynamics of population
density variation is the formation of isolated groups, i.e., stripelike or
spotted or coexistence of both. Our study shows that the spatially extended
model has not only more complex dynamic patterns in the space, but also chaos
and spiral waves. It may help us better understand the dynamics of an aquatic
community in a real marine environment.Comment: 6pages, revtex
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