1,108 research outputs found
The role of the international patent system in the transfer of technology to West Africa : case studies : Ghana and Nigeria
No full textThe principal aim of this thesis is to undertake a critical
examination of the role of the international patent system in the
transfer of technology to West Africa, particularly Ghana and Nigeria.
It focuses mainly on the patent systans and technology regulatory
regimes of the two countries. The study is intended to identify and
evaluate the impact of the international patent system on the transfer
and development of technology in this area.
The first chapter provides a theoretical foundation to some of
the more practical issues to be discussed in the subsequent chapters.
The Paris Convention and the diplomatic revision exercise thereof, as
well as other efforts and policies regarding patents and technology
transfer at various levels are discussed in Chapter Two. Chapters
Three to Eight consider the two case-studies undertaken in this
thesis. Chapter Three begins with the historical development of the
patent system in both Ghana and Nigeria, and the remaining chapters
continue with a discussion of the present patent and technology
regulatory regimes of both countries. Based on facts and figures the
two case-studies examine critically the patent law and systems and
technology transfer laws of these two countries including other
related institutional measures highlighting their strengths and
weaknesses.
The study argues that if the patent systems of both countries
are to play a meaningful role in the transfer and developnent of
technology they nust be utilized as a tool of economic policy and also
be related to the technology transfer regimes which nust necessarily
be integrated into the national technology policy which should, in
turn, be made an integral part of the entire national developnent
plan. It is concluded that it is only in this way that the patent
system can effectively contribute to the transfer of technology and
the development of indigenous technological capabilities in the two countries
Interior penalty discontinuous galerkin methods for electromagnetic and acoustic wave equations
No full textIntroduction: In this thesis we present and analyze the numerical approximation of the second
order electromagnetic and acoustic wave equation by the interior penalty (IP)
discontinuous Galerkin (DG) finite element method (FEM). In Part I we focus
on time-harmonic Maxwell source problems in the high-frequency regime. Part
II is devoted to the study of the IP DG FEM for time-dependent acoustic and
electromagnetic wave equations.
We begin by stating Maxwell's equations in time and frequency domain. We
proceed by a variational formulation of Maxwell's equations, and describe the
key challenges that are faced in the analysis of the Maxwell operator. Then,
we review conforming finite element methods to discretize the second order
Maxwell operator. We end this general introduction with some numerical results
to highlight the performance and feasibility of conforming FEM for Maxwell's
equations.
Chapter 2: In this chapter, we introduce and analyze the interior penalty discontinuous
Galerkin method for the numerical discretization of the indefinite time-harmonic
Maxwell equations in high-frequency regime. Based on suitable duality arguments,
we derive a-priori error bounds in the energy norm and the L2-norm. In
particular, the error in the energy norm is shown to converge with the optimal
order O(hminfs;`g) with respect to the mesh size h, the polynomial degree `, and
the regularity exponent s of the analytical solution. Under additional regularity
assumptions, the L2-error is shown to converge with the optimal order O(h`+1).
The theoretical results are confirmed in a series of numerical experiments on
triangular meshes.
The thesis' author's principal contributions are the proof of the L2-error
bound in Section 2.6, and the proof of Lemma 2.4.1.
Chapter 3: We present and analyze an interior penalty method for the numerical discretization
of the indefinite time-harmonic Maxwell equations in mixed form. The
method is based on the mixed discretization of the curl-curl operator developed
in [44] and can be understood as a non-stabilized variant of the approach
proposed in [63]. We show the well-posedness of this approach and derive optimal
a-priori error estimates in the energy-norm as well as the L2-norm. The
theoretical results are confirmed in a series of numerical experiments.
The thesis' author's principal contribution is the proof of the L2-error bound
in Section 3.6.
Chapter 4: The symmetric interior penalty discontinuous Galerkin finite element method
is presented for the numerical discretization of the second-order scalar wave
equation. The resulting stiffness matrix is symmetric positive definite and the
mass matrix is essentially diagonal; hence, the method is inherently parallel
and, leads to fully explicit time integration when coupled with an explicit timestepping
scheme. Optimal a priori error bounds are derived in the energy norm
and the L2-norm for the semi-discrete formulation. In particular, the error
in the energy norm is shown to converge with the optimal order O(hminfs;`g)
with respect to the mesh size h, the polynomial degree `, and the regularity
exponent s of the continuous solution. Under additional regularity assumptions,
the L2-error is shown to converge with the optimal order O(h`+1). Numerical
results confirm the expected convergence rates and illustrate the versatility of
the method.
Chapter 5: We develop the symmetric interior penalty discontinuous Galerkin (DG) method
for the spatial discretization in the method of lines approach of the timedependent
Maxwell equations in second-order form. We derive optimal a-priori
estimates for the semi-discrete error in the energy norm. For smooth solutions,
these estimates hold for DG discretizations on general finite element meshes.
For low-regularity solutions that have singularities in space, the theoretical estimates
hold on conforming, affine meshes. Moreover, on conforming triangular
meshes, we derive optimal error estimates in the L2-norm. Finally, we valuate
our theoretical results by a series of numerical experiments
KN and KN two-body physics: 2-5 GeV/c
No full textThe author reviews KN and KN induced reactions in the intermediate energy region to sketch present theoretical understanding and to high- light promising avenues for the future. He emphasizes several experiments that should advance or consolidate understanding: polarization for K/sup 0/p to K/sup +/n, K/sup -/p to K/sup 0/n, K/sub L//sup 0/p to K/sub s//sup 0/p; R parameter data for K/sup +/p to K /sup +/p and KN to Lambda pi and Sigma /sup +/ pi . A determination of precise cross section differences between K/sup +or-/p and K/sup +or- /n elastic scattering; between K and K charge exchange and between KN to pi Y and pi N to KY is described. (20 refs)
Analytic study of the Maxwell electromagnetic invariant in spinning and charged Kerr-Newman black-hole spacetimes
No full textAbstract The Maxwell invariant plays a fundamental role in the mathematical description of electromagnetic fields in charged spacetimes. In particular, it has recently been proved that spatially regular scalar fields which are non-minimally coupled to the Maxwell electromagnetic invariant can be supported by spinning and charged Kerr-Newman black holes. Motivated by this physically intriguing property of asymptotically flat black holes in composed Einstein-Maxwell-scalar field theories, we present a detailed analytical study of the physical and mathematical properties of the Maxwell electromagnetic invariant F KN r θ M a Q which characterizes the Kerr-Newman black-hole spacetime [here {r, θ} are respectively the radial and polar coordinates of the curved spacetime and {M, J = M a, Q} are respectively the mass, angular momentum, and electric charge parameters of the black hole]. It is proved that, for all Kerr-Newman black-hole spacetimes, the spin and charge dependent minimum value of the Maxwell electromagnetic invariant is attained on the equator of the black-hole surface. Interestingly, we reveal the physically important fact that Kerr-Newman spacetimes are characterized by two critical values of the dimensionless rotation parameter a ̂ ≡ a / r + [here r + (M, a, Q) is the black-hole horizon radius], a ̂ crit − = 3 − 2 2 and a ̂ crit + = 5 − 2 5 , which mark the boundaries between three qualitatively different spatial functional behaviors of the Maxwell electromagnetic invariant: (i) Kerr-Newman black holes in the slow-rotation a ̂ < a ̂ crit − regime are characterized by negative definite Maxwell electromagnetic invariants that increase monotonically towards spatial infinity, (ii) for black holes in the intermediate spin regime a ̂ crit − ≤ a ̂ ≤ a ̂ crit + , the positive global maximum of the Kerr-Newman Maxwell electromagnetic invariant is located at the black-hole poles, and (iii) Kerr-Newman black holes in the super-critical regime a ̂ < a ̂ crit + are characterized by a non-monotonic spatial behavior of the Maxwell electromagnetic invariant F KN r = r + θ M a Q along the black-hole horizon with a spin and charge dependent global maximum whose polar angular location is characterized by the dimensionless functional relation a ̂ 2 · (cos2 θ)max = 5 – 2 5
Triangular embeddings of Kn−Km with unboundedly large m
No full textAbstractThe author has proposed methods of constructing index 2 and 3 current graphs generating triangular embeddings of graphs Kn−Km with unboundedly large m (asn increases). As a result, triangular embeddings of graphs of many families of graphs Kn−Km with unboundedly large m were constructed. The paper gives a survey of these results and a short explanation of the methods
Author Correction: Considering serum alanine aminotransferase and gamma-glutamyltransferase levels together strengthen the prediction of impaired fasting glucose risk: a cross-sectional and longitudinal study
No full textSlowly rotating black holes in the novel Einstein–Maxwell-scalar theory
No full textWe investigate a slowly rotating black hole solution in a novel Einstein–Maxwell-scalar theory, which is prompted by the classification of general Einstein–Maxwell-scalar theory. The gyromagnetic ratio of this black hole is calculated, and it increases as the second free parameter increases, but decreases with the increasing parameter . In the Einstein–Maxwell-dilaton (EMD) theory, the parameter vanishes but the free parameter governing the strength of the coupling between the dilaton and the Maxwell field remains. The gyromagnetic ratio is always less than 2, the well-known value for a Kerr–Newman (KN) black hole as well as for a Dirac electron. Scalar hairs reduce the magnetic dipole moment in dilaton theory, resulting in a drop in the gyromagnetic ratio. However, we find that the gyromagnetic ratio of two can be realized in this Einstein–Maxwell-scalar theory by increasing and the charge-to-mass ratio Q/M simultaneously (recall that the gyromagnetic ratio of KN black holes is independent of Q/M). The same situation also applies to the angular velocity of a locally non-rotating observer. Moreover, we analyze the period correction for circular orbits in terms of charge-to-mass ratio, as well as the correction of the radius of the innermost stable circular orbits. It is found the correction increases with but decreases with Q/M. Finally, the total radiative efficiency is investigated, and it can vanish once the effect of rotation is considered
Einige extremale Aufgaben für die Klassen Kn(E) und P(E)
No full textThe abstracts (in two languages) can be found in the pdf file of the article.
Original author name(s) and title in Russian and Lithuanian:
Г. Кирьяцкий. Некоторые экстремальные задачи в классах Kn(E) и Р(Е)
E. G. Kirjackis. Kai kurie ekstremaliniai uždaviniai Kn(E) ir P(E) klasės
Ausdehnung einiger Sätze von Aksentjeff und Tshakaloff auf die Klassen Kn(D)
No full textThe abstracts (in two languages) can be found in the pdf file of the article.
Original author name(s) and title in Russian and Lithuanian:
Э. Г. Кирьяцкий. Распространение некоторых теорем Аксентьева и Чакалова на класс Kn(D)
E. G. Kirjackis. Kai kurios Aksentjevo ir Čakalovo teoremos Kn(D) klasėj
Superradiation of Dirac particles in KN black hole
No full textIn this article, we process the approximate wave function of the Dirac
particle outside the horizon of the KN ds black hole to effective potential V,
and then derive V (including real and imaginary parts). We know that fermions
cannot produce superradiation, but we can prove that Dirac particles in the KN
black hole background can have a special solution through a certain operation,
forming a Cooper pair, thus producing superradiation.We deal with the real and
imaginary parts separately. When V (real part or imaginary part) has a maximum
value, there may be a potential barrier outside the field of view to have a
chance to produce superradiation.Comment: 12 pages. arXiv admin note: text overlap with arXiv:2103.04239; text
overlap with arXiv:1501.06570 by other author
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