Abstract
A mathematical model of the transient
response of floor heating systems to ambient temperature variation is developed
based on equivalent thickness method. The model is then resolved numerically
using a sixth-order Rungge-Kutta scheme. Comparison
between floor and screed materials along with construction styles in
Europe
and
Abstract
In this paper a first comparative performance evaluation
of two virtual private Networks’ (VPNs) access
techniques is presented. Basically, there are two access techniques, namely
Network Access Server (NAS) initiated and Client initiated. VPNs performance rely on various variables, each of them
introduces its self on the network performance. In this research the end-to-end
delay and link utilization measures of the two VPNs’
access techniques are modeled, simulated and compared with each other. Our
experimental results obtained show that the models used to evaluate the
performance of the VPNs’ access techniques exhibit a
good degree of accuracy in predicting system behavior under various working
conditions. The results also demonstrate that the NAS initiated VPNs have less effect on the end to end delay and link
utilization than the Client initiated technique.
In this paper, a fast saturable absorber, with low saturation of about 20%,
distributed uniformly in the active fiber core is considered. A new approach has
been introduced to solve the propagation of CW mode-locking waves. In this
approach the three-coupled nonlinear differential equations that
describe the field inside the active fibers with distributed
saturable absorber are transformed into a single
nonlinear differential equation. This equation has a Duffing
oscillator form. By this approach, the design procedure will be
simplified and a new field of research will be opened. Since the Duffing oscillator
exhibits periodic, chaos, and periodic and chaos output.
Abstract
A generalized dynamic model for determining the transient behavior of an induction motor is presented. The starting conditions when the motor is supplied from a voltage source and a current source are investigated. The braking processes using reversal or dynamic braking are presented. Moreover, the response to load and source disturbances are studied. The model is a very simple tool to investigate the effect of parameter variations on the motor performance. The proposed method is so general that it can be used in studies involving simultaneous transients of any electrical machine.
A spontaneous ignition incident that occurred in a stockpile of animal feed concentrate is discussed. The incident illustrates a situation, which can cause a spontaneous ignition. This paper covers the chain of events during the incident and focuses on the layered investigation approach. This approach deals with management systems. The causes that led to the accident and the recommendations for reducing similar incidents in the future are discussed.
Keywords: Spontaneous ignition, feed concentrate
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Abstract Dynamical systems generated by semi-hyperbolic mappings are known to be exponentially expansive, [4]. It is also known that expansivity is one of the main features of “chaotic behaviour” of dynamical systems. In this paper, we show that a small delay perturbation of an ordinary differential equation with a homoclinic trajectory is “chaotic” in the sense of a recently proposed definition of chaos presented by Phil Diamond et.al. in [6]. Keywords: Semi--hyperbolic mappings; Chaotic systems. AMS Subject Classification: 58F15 |
The purpose of this paper is to test the time series models of the Jordanian stock market index between the years 1990-2000 using a range of different testing methodologies. The Dickey-Fuller, Philips-Person, the KPSS, the variance ratio, and the portmanteau tests were used to test the null hypothesis of a unit root against the alternative of no unit root. The results suggest that for monthly data, a random walk model fits the data well, while the martingale model fits daily and weekly data after adjusting for the effect on non-synchronous trading.
Talal Ali Al-Hawary & D. George McRae
Abstract
Our goal in this paper is to study completeness and cocompleteness in the category of loopless pointed matroids and strong maps which provide the beginnings of an elementary axiomatic theory for this category. Our work will be greatly influenced by Schlomiuk's work for the category of topological spaces and continuous mappings, [14].
Keywords: Matroid, Lp-Matroid, Uniform Matroid, Pointed Matroid, Strong map, Morphism, Category, Direct Sum.
2002 AMS Subject Classification: 05B35.
Abstract
Electronic transitions to the 7F4 and 7F6 manifolds from the ground 7F0 manifold in Eu:YAG were investigated in the infrared region for photon energies in the range 2700-5400 cm-1 . A total of six transitions were observed to the 7F4 manifold which is in excellent agreement with theoretical predictions. But the spectrum of the 7F6 manifold was rather complex. Eight lines were observed, two of them at 4959 and 4968 cm-1 were proved not to be genuine electronic transitions. The comparison of our work and previous absorption and flourescenece investigations revealed nine absorption features other than these two lines. The existance of these two lines were confirmed by recording the left- and right-circularly polarised light (L.C.P. and R.C.P.) spectra.
Comparison between theoretical calculated energies using J-mixing and the observed one gives population standard deviations of 3.23 and 8.75 cm-1 for the manifolds 7F4 and 7F6 , respectively, which is a good agreement.
Abstract
Several complexes of Ga(III)
with 4-carboxy maleianilic acid
4-carboxy phthalianilic acid and 4–carboxy
glutarianilic acid (abbreviated CM, CP and CG) have
been synthesized and characterized on the basis of elemental analyses, molar
conductance values, infrared, ultraviolet and nuclear mangetic resonance spectral data. The formulae [Ga(CM)3], [Ga(CP)3] and [Ga(CG)3] have been proposed for the complexes.
Moreover, the fungitoxcity of the ligands and their complexes were evaluated against two types
of fungi, Aspergillus