12,317 research outputs found
High performance computing of explicit schemes for electrofusion jointing process based on message-passing paradigm
The research focused on heterogeneous cluster workstations comprising of a number of CPUs in single and shared architecture platform. The problem statements under consideration involved one dimensional parabolic equations. The thermal process of electrofusion jointing was also discussed. Numerical schemes of explicit type such as AGE, Brian, and Charlies Methods were employed. The parallelization of these methods were based on the domain decomposition technique. Some parallel performance measurement for these methods were also addressed. Temperature profile of the one dimensional radial model of the electrofusion process were also given
Geometric Objects: A Quality Index to Electromagnetic Energy Transfer Performance in Sustainable Smart Buildings
Sustainable smart buildings play an essential role in terms of more efficient energy.
However, these buildings as electric loads are affected by an important distortion in the current and
voltage waveforms caused by the increasing proliferation of nonlinear electronic devices. Overall,
buildings all around the world consume a significant amount of energy, which is about one-third of
the total primary energy resources. Optimization of the power transfer process of such amount of
energy is a crucial issue that needs specific tools to integrate energy-efficient behaviour throughout
the grid. When nonlinear loads are present, new capable ways of thinking are needed to consider
the effects of harmonics and related power components. In this manner, technology innovations are
necessary to update the power factor concept to a generalized total or a true one, where different
power components involved in it calculation, properly reflect each harmonic interaction. This work
addresses an innovative theory that applies the Poynting Vector philosophy via Geometric Algebra
to the electromagnetic energy transfer process providing a physical foundation. In this framework,
it is possible to analyse and detect the nature of disturbing loads in the exponential growth of
new globalized buildings and architectures in our era. This new insight is based on the concept
of geometric objects with different dimension: vector, bivector, trivector, multivector. Within this
paper, these objects are correlated with the electromagnetic quantities responsible for the energy flow
supplied to the most common loads in sustainable smart buildings. Besides, it must be considered
that these phenomena are characterized by a quality index multivector appropriate even for detecting
harmonic sources. A numerical example is used to illustrate the clear capabilities of the suggested
index when it applies to industrial loads for optimization of energy control systems and enhance
comfort management in smart sustainable buildings
Coronal cooling and its signatures in the rapid aperiodic variability of Galactic black-hole candidates
The most popular models for the complex phase and time lags in the rapid
aperiodic variability of Galactic X-ray binaries are based Comptonization of
soft seed photons in a hot corona, where small-scale flares are induced by
flares of the soft seed photon input (presumably from a cold accretion disc).
However, in their original version, these models have neglected the additional
cooling of the coronal plasma due to the increased soft seed photon input, and
assumed a static coronal temperature structure. In this paper, our
Monte-Carlo/Fokker-Planck code for time-dependent radiation transfer and
electron energetics is used to simulate the self-consistent coronal response to
the various flaring scenarios that have been suggested to explain phase and
time lags observed in some Galactic X-ray binaries. It is found that the
predictions of models involving slab-coronal geometries are drastically
different from those deduced under the assumption of a static corona. However,
with the inclusion of coronal cooling they may even be more successful than in
their original version in explaining some of the observed phase and time lag
features. The predictions of the model of inward-drifting density perturbations
in an ADAF-like, two-temperature flow also differ from the static-corona case
previously investigated, but may be consistent with the alternating phase lags
seen in GRS 1915+105 and XTE J1550-564. Models based on flares of a cool disc
around a hot, inner two-temperature flow may be ruled out for most objects
where significant Fourier-frequency-dependent phase and time lags have been
observed.Comment: 23 pages, including 8 figures and 2 tables; accepted for publication
in ApJ; extended discussion w.r.t. original versio
Mid-infrared LEDs versus thermal emitters in IR dynamic scene simulation devices
In a radical departure from conventional thermal emitter-based dynamic IR scene simulation devices, we have tested
InAsSbP/InAs LEDs grown by liquid phase epitaxy and tuned at several peak-emitting wavelengths inside the mid-IR
band. Light uniformity, radiation apparent temperature (Ta), thermal resistance, and self heating details were
characterized at T=300 K in the microscale by calibrated infrared cameras in the 3-5 mm (light pattern) and 8-12 μm
(heat pattern) bands. We show that LEDs are capable of simulating very hot (Ta ³740 K) targets as well as cold objects
and low observable with respect to a particular background. We resume that cost effective LEDs enable a platform for
photonic scene projection devices able to compete with thermal microemitter MEMS technology in testing and
stimulating very high-speed infrared sensors used for military and commercial applications. Proposals on how to further
increase LEDs performance are given
Large-scale Ferrofluid Simulations on Graphics Processing Units
We present an approach to molecular-dynamics simulations of ferrofluids on
graphics processing units (GPUs). Our numerical scheme is based on a
GPU-oriented modification of the Barnes-Hut (BH) algorithm designed to increase
the parallelism of computations. For an ensemble consisting of one million of
ferromagnetic particles, the performance of the proposed algorithm on a Tesla
M2050 GPU demonstrated a computational-time speed-up of four order of magnitude
compared to the performance of the sequential All-Pairs (AP) algorithm on a
single-core CPU, and two order of magnitude compared to the performance of the
optimized AP algorithm on the GPU. The accuracy of the scheme is corroborated
by comparing the results of numerical simulations with theoretical predictions
Hot white dwarfs and the UV delay in dwarf novae
We calculate the effect of illumination of dwarf nova accretion discs by
radiation from a hot, central, white dwarf. We show that only for very hot
white dwarfs (Teff ~ 40 000$ K) the inner region of quiescent dwarf nova discs
are partially depleted so that the delay between the rise to outburst of the
optical and UV fluxes would be increased as suggested recently by King (1997).
This depletion, however, must create several small outbursts between main
outbursts, contrary to observations. Lower white dwarf temperatures may cause
the outburts to be of the `inside-out' type removing the UV delay. We conclude
that white dwarf irradiation of dwarf nova discs is not very efficient for
example because the UV radiation from the hot white dwarf does not penetrate
deep enough in the disc atmosphere. The total ablation of the inner disc by
e.g. evaporation (possibly related to illumination) appears to be a very
promising possibility, accounting for both the EUV delay and the general
lightcurves properties.Comment: 6 pages, 8 figures; accepted for publication in MNRA
Англійська мова для студентів електромеханічних спеціальностей
Навчальний посібник розрахований на студентів напряму підготовки
6.050702 Електромеханіка. Містить уроки, що структуровані за тематичними
розділами, граматичний коментар, короткі англо-український і українсько-
англійський словники та додатки, які спрямовані на закріплення загальних
навичок володіння англійською мовою. Акцентований на ɨсобливості
термінології, що застосовується у науково-технічній галузі, зокрема, в
електромеханіці та виконання запропонованих завдань, що буде сприяти
формуванню навичок перекладу з англійської та української мов, сприйняттю
письмової та усної англійської мови, вмінню письмового викладення
англійською мовою науково-технічних та інших текстів під час професійної
діяльності, спілкуванню з професійних та загальних питань тощо
- …