6,539 research outputs found
Relaxing in foam
We investigate the mechanical response of an aqueous foam, and its relation
to the microscopic rearrangement dynamics of the bubble-packing structure. At
rest, even though the foam is coarsening, the rheology is demonstrated to be
linear. Under flow, shear-induced rearrangements compete with
coarsening-induced rearrangements. The macroscopic consequences are captured by
a novel rheological method in which a step-strain is superposed on an otherwise
steady flow
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Form Accuracy Analysis of Cylindrical Parts Produced by Rapid Prototyping
Solid Freeform fabrication processes are being considered for creating fit and assembly
nature functional parts. It is extremely important that these parts are within allowable
dimensional and geometric tolerance. The part accuracy produced by rapid prototyping process
is greatly affected by the relative orientation of build and face normal directions. A systematic
method is needed to find the reliability of the created product. This paper discusses the work
done in this area and the effect of build orientation on the part form accuracy analysis of each
specified tolerance like circularity and cylindricity. Feasible build direction that can be used to
satisfy those tolerances is identified. It will help process engineer in selecting a build direction
that can satisfy a mathematical model of form tolerance.Mechanical Engineerin
Organizational Control Systems and Software Quality: A Cross-National Study.
This study explores the relationship between organizational control modes (behavior, outcome, and clan) andsoftware quality. Much of the previous work on organizational control has examined the choice of modes giventask characteristics. This research extends work in control theory by considering the impact of control modeson the increasingly critical organizational outcome of software quality. The research is set in the context ofsoftware development organizations in three of the largest software developing countries: India, Ireland, andIsrael (the 3Is). A cross sectional survey of 400 software development organizations across the 3Is will be usedto test the developed model. In addition to the theoretical contributions, the study will provide practicalimplications to support software project managers in making better organizational control choices
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Multi Objective Optimisation of Build Orientation for Rapid Prototyping with Fused Deposition Modeling (FDM)
The ability to select the optimal orientation of build up is one of the critical factors since
it affects the part surface quality, accuracy, build time and part cost. Various factors to be
considered in optimisation of build orientation for FDM are build material, support material,
build up time, surface roughness and total cost. Experiments were carried out and results are
analysed for varying build orientation for primitive geometries like cylinder. An appropriate
weighting factor has been considered for various objective functions depending on the specific
requirement of the part while carrying out multi-objective optimisation. These analyses will help
process engineers to decide proper build orientation.Mechanical Engineerin
Remnants from Gamma-Ray Bursts
We model the intermediate time evolution of a "jetted" gamma-ray burst by two
blobs of matter colliding with the interstellar medium. We follow the
hydrodynamical evolution of this system numerically and calculate the
bremsstrahlung and synchrotron images of the remnant. We find that for a burst
energy of erg the remnant becomes spherical after years
when it collects of interstellar mass. This result is
independent of the exact details of the GRB, such as the opening angle. After
this time a gamma-ray burst remnant has an expanding sphere morphology. The
similarity to a supernova remnant makes it difficult distinguish between the
two at this stage. The expected number of non-spherical gamma-ray burst
remnants is per galaxy for a beaming factor of 0.01 and a burst
energy of erg. Our results suggest that that the double-shell object
DEM L 316 is not a GRB remnant.Comment: 16 pages, 9 figures, Substantial revisions, Accepted by Ap
Search for quantum criticality in a ferromagnetic system UNi1-xCoxSi2
Polycrystalline samples of the isostructural alloys UNi1-xCoxSi2 (0 <= x <=
1) were studied by means of x-ray powder diffraction, magnetization, electrical
resistivity and specific heat measurements, at temperatures down to 2 K and in
magnetic fields up to 5 T. The experimental data revealed an evolution from
strongly anisotropic ferromagnetism with pronounced Kondo effect, observed for
the alloys with x < 0.98 and being gradually suppressed with rising Co-content,
to spin-glass-like states with dominant spin fluctuations, seen for the sample
with x = 0.98. Extrapolation of the value of TC(x) yields a critical
concentration xc = 1, at which the magnetic ordering entirely disappears. This
finding is in line with preliminary data collected for stoichiometric UCoSi2.Comment: to appear in Phys. Rev.
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(How) did attack advertisements increase affordable care act enrollments?
We examine the effects of exposure to negative information in attack advertisements in the context of Affordable Care Act (ACA) and Common Core (CC) education standards and show that they lead to an increase in the ACA enrollments and support of the CC standards. To explain this effect, we rely on the knowledge-gap theory and show that individuals who were exposed to more attack advertisements were also more likely to independently seek information, become more knowledgeable, and consequently support these subjects. In addition to an observational study, to test our hypotheses on the link between exposure to negative information, curiosity, and shifts in knowledge and support levels, we design and conduct a randomized experiment using a sample of 300 unique individuals. Our multi-methods research contributes to marketing literature by documenting a rare occasion in which exposure to attack advertisements leads to increased demand and unveiling the mechanisms through which this effect takes place
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