1,303 research outputs found
Building information deduced : state and potentials for Information query in building information modelling
In recent years, Building Information Models have become commonplace in building profession. The extensive use and increasing experience with BIM models offers new perspectives and potentials for design and planning. A recent stakeholder study conducted by the authors of this paper show that in practice models are no longer solely observed as culmination of knowledge in a 3d representation of future built structures, but as a source of information in itself. Experienced users of BIM want to Find Information within a model or across a set of these and Compare models in order to evaluate states of a model, differences in separate models or models from different point of time. Current BIM tools support both modes only in a rudimentary form. This paper discusses current modes of information query within and across BIM models, shows beneficial scenarios for building and planning practice through customised queries and exemplifies these on the base of a scripted tool. This customized approach is used to test approaches for a machine-based assessment of Level of detail and BIM-readiness in BIM models
Classical Boundary-value Problem in Riemannian Quantum Gravity and Taub-Bolt-anti-de Sitter Geometries
For an -invariant boundary the classical Dirichlet
problem of Riemannian quantum gravity is studied for positive-definite regular
solutions of the Einstein equations with a negative cosmological constant
within biaxial Bianchi-IX metrics containing bolts, i.e., within the family of
Taub-Bolt-anti-de Sitter (Taub-Bolt-AdS) metrics. Such metrics are obtained
from the two-parameter Taub-NUT-anti-de Sitter family. The condition of
regularity requires them to have only one free parameter () and constrains
to take values within a narrow range; the other parameter is determined as
a double-valued function of and hence there is a bifurcation within the
family. We found that {\it{any}} axially symmetric -boundary can be filled
in with at least one solution coming from each of these two branches despite
the severe limit on the permissible values of . The number of infilling
solutions can be one, three or five and they appear or disappear
catastrophically in pairs as the values of the two radii of are varied.
The solutions occur simultaneously in both branches and hence the total number
of independent infillings is two, six or ten. We further showed that when the
two radii are of the same order and large the number of solutions is two. In
the isotropic limit this holds for small radii as well. These results are to be
contrasted with the one-parameter self-dual Taub-NUT-AdS infilling solutions of
the same boundary-value problem studied previously.Comment: Minor changes and references added: Version in the Journa
Classical Boundary-value Problem in Riemannian Quantum Gravity and Self-dual Taub-NUT-(anti)de Sitter Geometries
The classical boundary-value problem of the Einstein field equations is
studied with an arbitrary cosmological constant, in the case of a compact
() boundary given a biaxial Bianchi-IX positive-definite three-metric,
specified by two radii For the simplest, four-ball, topology of the
manifold with this boundary, the regular classical solutions are found within
the family of Taub-NUT-(anti)de Sitter metrics with self-dual Weyl curvature.
For arbitrary choice of positive radii we find that there are three
solutions for the infilling geometry of this type. We obtain exact solutions
for them and for their Euclidean actions. The case of negative cosmological
constant is investigated further. For reasonable squashing of the three-sphere,
all three infilling solutions have real-valued actions which possess a ``cusp
catastrophe'' structure with a non-self-intersecting ``catastrophe manifold''
implying that the dominant contribution comes from the unique real
positive-definite solution on the ball. The positive-definite solution exists
even for larger deformations of the three-sphere, as long as a certain
inequality between and holds. The action of this solution is
proportional to for large and hence larger radii are
favoured. The same boundary-value problem with more complicated interior
topology containing a ``bolt'' is investigated in a forthcoming paper.Comment: 20 pages, 11 figures; Latex; Revised version with important new
results on real infilling solutions and corrections. To appear in Nuclear
Physics B, issue 648 (1,2), pp. 397-41
Coherent states for exactly solvable potentials
A general algebraic procedure for constructing coherent states of a wide
class of exactly solvable potentials e.g., Morse and P{\"o}schl-Teller, is
given. The method, {\it a priori}, is potential independent and connects with
earlier developed ones, including the oscillator based approaches for coherent
states and their generalizations. This approach can be straightforwardly
extended to construct more general coherent states for the quantum mechanical
potential problems, like the nonlinear coherent states for the oscillators. The
time evolution properties of some of these coherent states, show revival and
fractional revival, as manifested in the autocorrelation functions, as well as,
in the quantum carpet structures.Comment: 11 pages, 4 eps figures, uses graphicx packag
Edible insects unlikely to contribute to transmission of coronavirus SARS-CoV-2
In the context of food safety, edible insects are evaluated for biological hazards such as microbial pathogens according to regulations currently in place. When the European Food Safety Authority evaluated the hazards of edible insects as a potential source of pathogenic viruses for humans and livestock, the novel zoonotic coronavirus SARS-CoV-2 had not yet emerged but other pathogenic coronaviruses such as SARS (SARS-CoV) and MERS (MERS-CoV) were known. As a result of the COVID-19 pandemic, animal sources of protein for human consumption are being evaluated for the risks of being a transmission vector of coronaviruses, like SARS-CoV-2. Insects lack a receptor that can bind SARS-CoV-2, thus preventing the virus from replicating in insects, unlike some vertebrate livestock species and companion animals. Despite extensive monitoring, coronaviruses have never been recorded in insect microbiomes. Contamination of insects produced for food or feed may occur during the production process, resulting from rearing substrate or from insect farmers. However, the currently permitted rearing substrates do not include animal products and the farming process is highly automated, thus limiting interactions between farmers and insects. If contamination would still occur, the fact that the insects in production are not hosts to SARS-CoV-2 precludes virus replication and the further processing of the insects will destroy the contamination. We conclude that the hazard of edible insects being a transmission vector of SARS-CoV-2 is extremely low.</p
Effect of FET geometry on charge ordering of transition metal oxides
We examine the effect of an FET geometry on the charge ordering phase diagram
of transition metal oxides using numerical simulations of a semiclassical model
including long-range Coulomb fields, resulting in nanoscale pattern formation.
We find that the phase diagram is unchanged for insulating layers thicker than
approximately twice the magnetic correlation length. For very thin insulating
layers, the onset of a charge clump phase is shifted to lower values of the
strength of the magnetic dipolar interaction, and intermediate diagonal stripe
and geometric phases can be suppressed. Our results indicate that, for
sufficiently thick insulating layers, charge injection in an FET geometry can
be used to experimentally probe the intrinsic charge ordering phases in these
materials.Comment: 4 pages, 4 postscript figure
Critical exponents of directed percolation measured in spatiotemporal intermittency
A new experimental system showing a transition to spatiotemporal
intermittency is presented. It consists of a ring of hundred oscillating
ferrofluidic spikes. Four of five of the measured critical exponents of the
system agree with those obtained from a theoretical model of directed
percolation.Comment: 7 pages, 12 figures, submitted to PR
The Middle Way: East Asian masters studentsâ perceptions of critical argumentation in U.K. universities.
The paper explores the learning experiences of East Asian masters students in dealing with Western academic norms of critical thinking in classroom debate and assignment writing. The research takes a cultural approach, and employs grounded theory and case study methodology, the aims being for students to explain their perceptions of their personal learning journeys. The data suggest that the majority of students interviewed rejected full academic acculturation into Western norms of argumentation. They instead opted for a âMiddle Wayâ that synergizes the traditional cultural academic values held by many East Asian students with those elements of Western academic norms that are perceived to be aligned with these. This is a relatively new area of research which represents a challenge for British lecturers and students
Green manure in coffee systems in the region of Zona da Mata, Minas Gerais: characteristics and kinetics of carbon and nitrogen mineralization.
The use of green manure may contribute to reduce soil erosion and increase the soil organic matter content and N availability in coffee plantations in the Zona da Mata, State of Minas Gerais, in Southeastern Brazil. The potential of four legumes (A. pintoi, C. mucunoides, S. aterrimum and S. guianensis)to produce above-ground
biomass, accumulate nutrients and mineralize N was studied in two coffee plantations of subsistence farmers under different climate conditions. The biomass production of C. mucunoides was influenced by the shade of the coffee plantation.C. mucunoides tended to mineralize more N than the other legumes due to the low polyphenol content and polyphenol/N ratio. In the first year, the crop establishment of A. pintoi in the area took longer than of the other legumes, resulting in lower biomass production and N2 fixation. In the long term, cellulose was the main
factor controlling N mineralization. The biochemical characteristics, nutrient accumulation and biomass production of the legumes were greatly influenced by
the altitude and position of the area relative to the sun
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