Elementary Techniques Research Articles

Optical theorems and physical bounds on absorption in lossy media.

Two different versions of an optical theorem for a scattering body embedded inside a lossy background medium are derived in this paper. The corresponding fundamental upper bounds on absorption are then obtained in closed form by elementary optimization techniques. The first version is formulated in terms of polarization currents (or equivalent currents) inside the scatterer and generalizes previous results given for a lossless medium. The corresponding bound is referred to here as a variational bound and is valid for an arbitrary geometry with a given material property. The second version is formulated in terms of the T-matrix parameters of an arbitrary linear scatterer circumscribed by a spherical volume and gives a new fundamental upper bound on the total absorption of an inclusion with an arbitrary material property (including general bianisotropic materials). The two bounds are fundamentally different as they are based on different assumptions regarding the structure and the material property. Numerical examples including homogeneous and layered (core-shell) spheres are given to demonstrate that the two bounds provide complimentary information in a given scattering problem.

An Elementary Proof of the General Poincaré Formula for λ-additive Measures

In a previous paper of ours [4], we presented the general formula for lambda-additive measure of union of n sets and gave a proof of it. That proof is based on the fact that the lambda-additive measure is representable. In this study, a novel and elementary proof of the formula for lambda-additive measure of the union of n sets is presented. Here, it is also demonstrated that, using elementary techniques, the well-known Poincare formula of probability theory is just a limit case of our general formula.

Catalytic properties of reduced graphene oxide in acetylene hydrogenation

Catalytic properties of thermally reduced (TRGO) and nitrogen-doped thermally reduced (N-TRGO) graphene oxides in acetylene hydrogenation in the temperature range of 50–400 °C were studied. The N-TRGO and TRGO materials were characterized by transmission and scanning electron microscopy, X-ray diffraction, Raman, infrared and X-ray photoelectron spectroscopies as well as elementary analysis techniques. The nitrogen incorporation in the graphene structure decreases the total activity for acetylene hydrogenation and the selectivity for ethylene. Oxygen-containing functional groups like ketone and hydroxyl groups may also contribute to catalytic activity. Methane, as a by-product, is produced due to acetylene hydrogenolysis that occurs on the structural defects.

Two components is too simple: an example of oscillatory Fisher–KPP system with three components

AbstractIn a recent paper by Cantrell et al. [9], two-component KPP systems with competition of Lotka–Volterra type were analyzed and their long-time behaviour largely settled. In particular, the authors established that any constant positive steady state, if unique, is necessarily globally attractive. In the present paper, we give an explicit and biologically very natural example of oscillatory three-component system. Using elementary techniques or pre-established theorems, we show that it has a unique constant positive steady state with two-dimensional unstable manifold, a stable limit cycle, a predator–prey structure near the steady state, periodic wave trains and point-to-periodic rapid travelling waves. Numerically, we also show the existence of pulsating fronts and propagating terraces.

Solving the one-dimensional Ising chain via mathematical induction: an intuitive approach to the transfer matrix

The aim of this work is to present a formulation to solve the one-dimensional Ising model using the elementary technique of mathematical induction. This formulation is physically clear and leads to the same partition function form as the transfer matrix method, which is a common subject in the introductory courses of statistical mechanics. In this way our formulation is a useful tool to complement the traditional more abstract transfer matrix method. The method can be straightforwardly generalised to other short-range chains, coupled chains and is also computationally friendly. These two approaches provide a more complete understanding of the system, and therefore our work can be of broad interest for undergraduate teaching in statistical mechanics.

A Constructive Proof of Helmholtz’s Theorem

Summary It is a known result that any vector field ${\boldsymbol{u}}$ that is locally Hölder continuous on an arbitrary open set $\Omega\subset \mathbb{R}^3$ can be written on $\Omega$ as the sum of a gradient and a curl. Should $\Omega$ be unbounded, no conditions are required on the behaviour of ${\boldsymbol{u}}$ at infinity. We present a direct, self-contained proof of this theorem that only uses elementary techniques and has a constructive character. It consists in patching together local solutions given by the Newtonian potential that are then modified by harmonic approximations—based on solid spherical harmonics—to assure convergence near infinity for the resulting series.

More cardinal inequalities in T1/Urysohn spaces

In this paper we provide a partial positive answer to the question 2 in [8]: Do we have |X|≤2L(X)Fa(X)ψ(X), for every T2–space X? Precisely, in Theorem 2.6 we show that |X|≤2L(X)Fa(X)ψθ(X) for Urysohn spaces. Even more, we use cardinal functions recently introduced by Basile, Bonanzinga and Carlson in [4] to generalize some cardinal inequalities; among others, in the Theorem 2.8, we provide a result related with the well known inequality of Hajnal and Juhász: |X|≤2c(X)χ(X); and in the Theorem 2.10, we generalize the inequality |X|≤2wLc(X)χ(X), for any Urysohn space X; due to Ofelia Alas ([1]). Some proofs of the theorems provided in this paper use the elementary submodels technique.

2015 개정 실과교육과정 내 친환경 미래 농업 내용에 대한 초등교사의 지식, 기술, 태도

이 연구의 목적은 2015 개정 실과교육과정 내 친환경 미래 농업에 대한 교육과정 내용을 분석하고, 실 제 교육과정을 운영 및 지도하는 초등교사의 친환경 미래 농업에 대한 지식, 기술, 태도에 대한 교사의 인 식을 알아보아 이를 현장에서 실천하기 위한 실과교육의 방향을 제안하고자 하는데 있다. 또한 2015 개정 실과교육과정 내 친환경 미래 농업에 대한 교육과정 내용, 초등교사의 배경변인 및 교양농업교육과 관련된 경험의 유무에 따른 친환경 미래 농업에 대한 지식, 기술, 태도 수준과 이들 간의 상관관계를 알아보고자 하였다. 이를 위해 문헌분석과 설문조사를 활용한 양적연구를 실시하였으며 2015 개정 실과교육과정 내 친환경 미래 농업과 관련 있는 영역, 핵심개념, 성취기준 및 내용을 분석하였다. 서울 및 경기도에 재직 중인 초등교사 43명을 임의표집하여 온라인 설문조사를 실시한 결과, 배경변인에 따른 친환경 미래 농업 에 대한 초등교사의 태도 수준의 차이는 교직경력, 실과 전공 유무, 실과 교과 지도 경험 유무에서 유의미 하게 나타났다. 교직경력이 10년 이상일수록, 실과를 전공한 교사일수록, 실과를 지도한 경험이 있는 교 사일수록 친환경 미래 농업의 중요성을 높게 지각하고 있다는 것을 알 수 있었다. 친환경 미래 농업 내용에 대한 지식과 기술, 친환경 미래 농업 내용에 대한 지식과 태도, 친환경 미래 농업 내용에 대한 기술과 태도는 각각 유의미한 상관관계가 있었다. 상관분석결과, 친환경 미래 농업 내용 에 대한 기술과 태도의 모든 하위요인 영역에서 정적인 상관관계가 있는 것으로 분석되었으며 태도의 하 위요인 중 미래 농업이 적용된 도시의 변화에 있어 가장 큰 관련이 있는 것으로 나타났다. 이러한 결과를 종합하여 얻은 결론은 다음과 같다. 첫째, 초등교사를 상대로 친환경 미래 농업 관련 교육 강화를 통해 친환경 미래 농업과 관련된 교사의 지식수준 향상을 위해 친환경 미래 농업과 관련된 연수 및 체험의 다양한 기회를 마련하여 지속적인 전문 성 신장방안을 마련해야 할 것이다. 둘째, 실생활에서 실천하고 체험할 수 있는 친환경 미래 농업교육과 관련된 다양한 교수학습 방법 및 교수학습 자료를 개발하여 학교 현장에서 적극적으로 활용할 수 있는 방안을 모색해야 할 것이다. 셋째, 초등교사 양성 기관의 교육과정에 2015 개정 실과교육과정 내 친환경 미래 농업에서 강조하는 ‘지속가능’, ‘농업체험’ 등을 반영하여 체계적인 친환경 미래 농업 교육이 이루어져야 할 것이다. 본 연구에서는 친환경 미래 농업에 대한 지식, 기술, 태도 간 유의미한 영향을 미친다는 사실을 확인하 였으며 이는 초등교사가 친환경 미래 농업에 대한 중요성과 의의를 깨닫고 정확한 인식이 있을 때 농업교 육에 관한 긍정적인 태도가 형성되고, 수업의지로 발현됨을 밝혀냈다는 것에 의의가 있다. 따라서 학교 현장에서는 교사들이 친환경 미래 농업과 관련하여 지식, 기술을 증진시키기 위해 다양한 시도가 이루어져야 할 것으로 보인다.

On an elementary ratio technique for proving convergence of known distributions

Proschan offered a simple informal, the so called, ratio technique for deriving the convergence of binomial distribution to a limiting normal as the number of trials increases to infinity (see also Bagui and Mehra). The technique offers only a heuristic derivation and not a viable proof. The object of the present article is to provide a frame-work so that this heuristic technique gets accepted as a method of proof, under a set of conditions that are readily verifiable.

On the Diophantine Equation 3x + p5y = z2

In this paper, we present new series of solutions of the Diophantine equation 3x + p5y = z2 where p is a prime number and x; y and z are nonnegative integers using elementary techniques. Moreover, the equation has no solution if p is equivalent to 5 or 7 modulo 24.

Gossez’s skew linear map and its pathological maximally monotone multifunctions

In this note, we give a generalization of Gossez’s example of a maximally monotone multifunction such that the closure of its range is not convex, using more elementary techniques than in Gossez’s original papers. We also discuss some new properties of Gossez’s skew linear operator and its adjoint.

Parallel, physics-oriented, monolithic solvers for three-dimensional, coupled finite element models of lithium-ion cells

This work is concerned with physics-oriented, monolithic solvers for the large, sparse systems of linear equations arising in three-dimensional, coupled finite element models of lithium-ion cells and related electrochemical systems. The governing equations are obtained from a thermodynamically consistent transport theory and established both for the general case with varying temperature and for the special case of an isothermal scenario. For preconditioning the respective monolithic systems of linear equations, each system is first divided into distinct blocks associated with individual physical fields, and the resulting block structure is then respected and preserved during the preconditioning process. Field-specific preconditioning components are independently selected and synthesized, resulting in greater flexibility compared to conventional preconditioning approaches. Two different concepts are developed for constructing advanced preconditioners from elementary preconditioning techniques, and the GMRES and BiCGSTAB methods are adopted as linear solvers. Three comprehensive numerical examples involving up to 7.7 million degrees of freedom are studied. In each example, the novel preconditioners exhibit much better robustness, efficiency, and weak parallel scalability than conventional ones in terms of both solver iteration counts and total solver times including preconditioner setup. Thus, the new solution approaches are the key to large-scale, high-performance computations in settings with strict demands on accuracy.

Defining the proton radius: A unified treatment

Background: There is significant current interest in knowing the value of the proton radius and also its proper definition. Purpose: Combine the disparate literatures of hydrogen spectroscopy and diverse modern parton distributions to show that the quantity $r_p^2\equiv -6 G_E'(0)$ is the relativistically proper definition that originates from the separate bodies of work. Methods: Use perturbation theory, light-front dynamics and elementary techniques to find relativistically correct definitions of the proton radius and charge density. Results: It is found that the very same proton radius is accessed by measurements of hydrogen spectroscopy and elastic lepton scattering. The derivation of the mean-square radius as a moment of a spherically symmetric three-dimensional density is shown to be incorrect. A relativistically-correct, two-dimensional charge density is related to the diverse modern literature of various parton distributions. Relativistically invariant moments thereof are derived in a new moment expansion, the RME.

Mechanical and Thermal Properties of PVC , PS and PMMA with New Resinounce Plasticizers

A new plasticizers prepared and characterized as ester of 1,3-bis[4-(3,5-dimethyl ol-4-hydroxy phenyl-isopropylidene)-2,6-dimethylol phenoxy]propane-2-ol(I) as described. The esters prepared were butyrate, caproate and benzoate.The new plasticizers were characterized by elementary analysis ,spectroscopic techniques and molecular weight determination. The physical ,rheological and thermal stability characteristic are also included. The efficiency of plasticization were examined with polyvinylchloride(PVC), polystyrene(PS) and polymethyl methacrylate(PMMA). This plasticizers shows a great effect in increasing the melt flow index of the polymers and decreasing the total input in the melting process. DOI : 10.7176/JNSR/9-6-05 Publication date :March 31 st 2019

Generalizations of the arithmetic case of Blackwell’s renewal theorem

Using elementary techniques, for discrete-time renewal processes, we provide asymptotic results for the probability of renewal at time n using the binomial moments of the underlying discrete distribution. Using these results, we also provide an alternative derivation of the asymptotics for the first two moments of the number of renewals up to time n.

Ontology Alignment using Stable Matching

Ontology matching is a solution to the problem of semantic heterogeneity in the integration and sharing of information. It consists in establishing mappings between entities which semantically belong to different ontologies. Most ontology mapping approaches use elementary matching techniques (eg, string-based methods, linguistic methods, etc.). These techniques map the elements by analyzing the entities in isolation and ignoring their relationships with other entities (father/son, brother, etc.). Bypassing the latter aspects, the determination of the semantics of an entity is often difficult. Hence, the structural information of an ontology plays an important role in ontologies mapping. In this work, we study methods of structural alignment. We adopt two alignment methods that are based on the structure. The first, called Method of Similarity of Inheritance (MSI), applies the initial similarity method based on the concepts and integrates the inheritance relation (father/son) into the calculation of similarity. The second, called Method of Sibling Similarity (MSS), involves sibling relationships to enrich the similarity score between two concepts. Moreover, we enhance the mappings selection strategy by integrating the stable marriage algorithm as an optimal matching strategy. This algorithm improves the ontology alignment quality through efficient optimization techniques and creates a faster and more robust alignment method.

Convergence Rates for Fourier Partial Sums of Polygons and Periodic Splines

Polygons can be seen as closed parameterized curves. Their parameterizations can be chosen as continuous, piecewise linear, periodic functions. Such functions possess a convergent Fourier series. Often polygons are classified with Fourier descriptors defined via Fourier coefficients of the parameterization. This fact motivates the discussion of the approximation error of Fourier partial sums of piecewise linear functions. More generally, the paper investigates convergence rates for periodic splines using elementary techniques of calculus. For example, such splines are used as curve parameterizations for active contours. Error bounds are shown to be best possible. An interesting effect is that the convergence rate at knots is different for odd and even degrees of piecewise polynomials. The slower rate for polynomials of odd degree can be used to detect dominant corners of contours.

Waves without the wave equation: Examples from nonlinear acoustics

The traditional wave equation is mostly, if not always, obtained from a system of first order partial differential equations augmented by constitutive relations. These are often nonlinear and linearizations are forcibly applied.In a nonlinear system of first order partial differential equations the criterion for hyperbolicity, necessary for the description of wave phenomena, involves the solution. It is therefore possible that solutions may evolve in such a way that hyperbolicity is challenged in the sense that the system comes close to not being hyperbolic. We use the recently introduced formulation for nonlinear acoustic disturbances to illustrate. When hyperbolicity deteriorates, standard numerical methods and the heuristics surrounding wave motion may be compromised. To overcome such difficulties we introduce the notion of inverse characteristicwhich, at least in the examples, reduces numerical calculations to elementary techniques and clarifies intuition. Analysis of inverse characteristics leads to two systems of ordinary differential equations that have time-like trajectories and space-varying associated curves. Time-like trajectories give rise to an alternative measure of time in terms of which space-like trajectories are easier to analyze. Space-varying curves enable the analysis of shock phenomena in a direct way. We give conditions under which an initially mild challenge of hyperbolicity, represented by pressure, develops into a severe challenge. Under these conditions violent velocity shocks develop from an initially undisturbed state.

DEVELOPMENT MODEL OF LEARNING BASKETBALL BASED MODIFICATION GAMES FOR SECONDARY HIGH SCHOOL


 The purpose of this research and development is to produce a model of learning basketball skills on learning physical education for students middle school first. In addition, this research and development is conducted to obtain information in depth about: development and application of learning model of bolabasket skill (hamidi) on basketball game for students of middle school first and know the effectiveness, efficiency and attractiveness of student to model made. This research and development use research & development (R & D) research method from borg and gall. The subjects in this research and development are the students of the first class VII students aged 13-14 years as many as 98 people. The instruments used in this research and development are questionnaires, questionnaires, battery test tests used to collect basic engineering skill data, as well as "game performance instrument test" instruments to collect data on students' basketball skills, as for stages in research and this development is, at the stage of: (1) needs analysis, (2) expert evaluation (initial product evaluation); (3) limited testing (small group trial); and (4) the main test (field testing). The model effectiveness test uses a battery test test to determine the level of mastery of students' basic basketball techniques and "GPAI tests" to find out the skill level of play. Data analysis technique used is "t-test" based on data analysis, for elementary technique aspect of students obtained the average value of pre test 29.86 and average post test 50.36, standard deviation pre test 5.5. and post test 6.0, value t -32.36 significance level 0.05 Because H0 is rejected means an increase in basic engineering capability. As for the skills to play based on data analysis using the test "t" obtained the average value of pre test 1.6 and average post test 3.83, standard deviation pre test 0.54 and post test 15.02, t value 0.085 significance level 0.05 Because H0 rejected means there is an increase in the ability of students' playing skills. Based on the data, it can be stated that basketball skill learning model for middle school first students is developed effectively and can improve basic technique skills and basketball playing skills of first medium school students.
 
 Keywords: Development, Game-based learning model, basic engineering skills, playing skills, basketball, students middle school first.

A discretization result for some optimization problems in framework spaces with polyhedral obstacles and the Manhattan metric

In this work we consider the shortest path problem and the single facility Weber location problem in any real space of finite dimension where there exist different types of polyhedral obstacles or forbidden regions. These regions are polyhedral sets and the metric considered in the space is the Manhattan metric. We present a result that reduce these continuous problems into problems in a “add hoc” graph, where the original problems can be solved using elementary techniques of Graph Theory. We show that, fixed the dimension of the space, both the reduction and the resolution can be done in polynomial time.