5,804 research outputs found
Seeing the invisible: from imagined to virtual urban landscapes
Urban ecosystems consist of infrastructure features working together to provide services for inhabitants. Infrastructure functions akin to an ecosystem, having dynamic relationships and interdependencies. However, with age, urban infrastructure can deteriorate and stop functioning. Additional pressures on infrastructure include urbanizing populations and a changing climate that exposes vulnerabilities. To manage the urban infrastructure ecosystem in a modernizing world, urban planners need to integrate a coordinated management plan for these co-located and dependent infrastructure features. To implement such a management practice, an improved method for communicating how these infrastructure features interact is needed. This study aims to define urban infrastructure as a system, identify the systematic barriers preventing implementation of a more coordinated management model, and develop a virtual reality tool to provide visualization of the spatial system dynamics of urban infrastructure. Data was collected from a stakeholder workshop that highlighted a lack of appreciation for the system dynamics of urban infrastructure. An urban ecology VR model was created to highlight the interconnectedness of infrastructure features. VR proved to be useful for communicating spatial information to urban stakeholders about the complexities of infrastructure ecology and the interactions between infrastructure features.https://doi.org/10.1016/j.cities.2019.102559Published versio
Midwest China Oral History Interviews
Father\u27s Early Life: education; early contacts with Christianity; graduates from Nanking Military Academy and is assigned to Northeastern China by Kuomintang, 1937-1945; escape from Mainland China, 1949-1950; experiences in Hong Kong and Malaysia.
Early Life: education and life in Yung, evacuation to Hong Kong, 1949; experiences in Hong Kong and Taiwan; future of Christianity in the People\u27s Republic of China and Hong; influential Christians in narrator\u27s life.https://digitalcommons.luthersem.edu/china_histories/1056/thumbnail.jp
A Two Step Approach to Weighted Bipartite Link Recommendations
Many real world person-person or person-product relationships can be modeled
graphically. More specifically, bipartite graphs can be especially useful when
modeling scenarios that involve two disjoint groups. As a result, many existing
papers have utilized bipartite graphs for the classical link recommendation
problem. In this paper, using the principle of bipartite graphs, we present
another approach to this problem with a two step algorithm that takes into
account frequency and similarity between common edges to make recommendations.
We test this approach with bipartite data gathered from the Epinions and
Movielens data sources, and find it to perform with roughly 14 percent error,
which improves upon baseline results. This is a promising result, and can be
refined to generate even more accurate recommendations
Silicon resistor to measure temperature during rapid thermal annealing
A resistor composed of a piece of Si wafer and two thin silver wires attached to it, can reliably sense the temperature during rapid thermal annealing (RTA). As constant electric current passes through the Si piece, the resistivity change of Si with temperature produces a voltage signal that can be readily calibrated and converted to an actual temperature of the samples. An accuracy better than ±10 °C is achieved between 300° and 600 °C
Simultaneous planar growth of amorphous and crystalline Ni silicides
We report a solid-state interdiffusion reaction induced by rapid thermal annealing and vacuum furnace annealing in evaporated Ni/Si bilayers. Upon heat treatment of a Ni film overlaid on a film of amorphous Si evaporated from a graphite crucible, amorphous and crystalline silicide layers grow uniformly side by side as revealed by cross-sectional transmission electron microscopy and backscattering spectrometry. This phenomenon contrasts with the silicide formation behavior previously observed in the Ni-Si system, and constitutes an interesting counterpart of the solid-state interdiffusion-induced amorphization in Ni/Zr thin-film diffusion couples. Carbon impurity contained in the amorphous Si film stabilizes the amorphous phase. Kinetic and thermodynamic factors that account for the experimental findings are discussed
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Cell constant studies of bipolar and tetrapolar electrode systems for impedance measurement
In comparison to the bipolar or two-electrode system, the tetrapolar or four-electrode arrangement is a well-known technique to reduce electrode polarisation just as effectively. However, recent studies have showed that phenomena such as negative sensitivity and multiple current paths can compromise the advantages of the tetrapolar electrode arrangement, thereby potentially limiting its applications. This paper reveals a novel method to evaluate the performance of the different electrode systems in which the concept of cell constant is extended to an impedance measurement system. We employ it as a standardised parameter to quantitatively analyse planar electrode systems in bipolar and tetrapolar measurement modes. Indeed, the cell constant is a key parameter in conductivity sensors to evaluate electrodes designs since it is independent of any readout electronics. A comparison of measurement modes using finite element methods (FEM) simulations and measurements for sodium chloride solutions is presented. While the cell constant of the bipolar electrode system is one order of magnitude greater than that of the tetrapolar arrangement, it shows large discrepancy over the measured frequency range. In contrast, despite the existence of measurement errors, the tetrapolar arrangement yields a uniform cell constant and good agreement with the simulations.This work is partially supported by the Isaac Newton Trust.This is the author accepted manuscript. The final version is available from Elsevier via http://dx.doi.org/10.1016/j.snb.2015.07.08
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LED-Assisted Degradation of Aromatic Organics Using Cu2O Photocatalysts
In this work, we successfully synthesized rhombic dodecahedral Cu2O nanocrystals with a size of 300 – 400 nm using a facile hydrothermal method. The as-prepared photocatalyst with narrow bandgap is activated using low power visible LED light sources and shows high efficiency in degrading aromatic organic compounds including toluene and chlorobenzene. The OH substitution leads to oxidation/ionization potential drops while the nature of the p-type Cu2O contributes to an effective single electron transfer reaction
Levinson's Theorem for Dirac Particles
Levinson's theorem for Dirac particles constraints the sum of the phase
shifts at threshold by the total number of bound states of the Dirac equation.
Recently, a stronger version of Levinson's theorem has been proven in which the
value of the positive- and negative-energy phase shifts are separately
constrained by the number of bound states of an appropriate set of
Schr\"odinger-like equations. In this work we elaborate on these ideas and show
that the stronger form of Levinson's theorem relates the individual phase
shifts directly to the number of bound states of the Dirac equation having an
even or odd number of nodes. We use a mean-field approximation to Walecka's
scalar-vector model to illustrate this stronger form of Levinson's theorem. We
show that the assignment of bound states to a particular phase shift should be
done, not on the basis of the sign of the bound-state energy, but rather, in
terms of the nodal structure (even/odd number of nodes) of the bound state.Comment: Latex with Revtex, 7 postscript figures (available from the author),
SCRI-06109
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