Concepts of Materials Science

This short book describes ten fundamental concepts – big ideas – of materials science. Some of them come from mainstream physics and chemistry, including thermodynamic stability and phase diagrams, symmetry, and quantum behaviour. Others are about restless atomic motion and thermal fluctuations, defects in crystalline materials as the agents of change in materials, nanoscience and nanotechnology, materials design and materials discovery, metamaterials, and biological matter as a material. A cornerstone of materials science is the idea that materials are complex systems that interact with their environments and display the emergence of new science from the collective behaviour of atoms and defects. Great attention is paid to the clarity of explanations using only high school algebra and quoting the occasional useful formula. Exceptionally, elementary calculus is used in the chapter on metamaterials. It is not a text-book, but it offers undergraduates and their teachers a unique overview and insight into materials science. It may also help graduates of other subjects to decide whether to study materials science at postgraduate level.

Volume decay and concentration of high-dimensional Euclidean balls – a PDE and variational perspective

It is a well-known fact – which can be shown by elementary calculus – that the volume of the unit ball in \mathbb{R}^{n} decays to zero and simultaneously gets concentrated on the thin shell near the boundary sphere as n\nearrow\infty. Many rigorous proofs and heuristic arguments are provided for this fact from different viewpoints, including Euclidean geometry, convex geometry, Banach space theory, combinatorics, probability, discrete geometry, etc. In this note, we give yet another two proofs via the regularity theory of elliptic partial differential equations and calculus of variations.

Elemental access to limit cycle existence in Biomath education.

This paper originated from the desire to develop elementary calculus based tools to empower students, not necessarily with a strong mathematical background, to test predator-prey related models for boundedness of solutions and for the existence of limit cycles. There are several well-known methods available to prove, or disprove, the existence of bounded solutions to systems of differential equations. These methods rely on Liénard's theorem or using Dulac or Lyaponov functions. The level of mathematics required in the study of differential equations is not addressed in the courses presented on the first year level, and students in biology, ecology, economics and other fields are often not suitably equipped to perform these advanced techniques.The conditions under which a unique limit cycle exists in predator-prey systems is considered a primary problem in mathematical ecology. A great deal of mathematical effort has gone into trying to establish simple, yet general, theorems which will allow one to decide whether a given set of nonlinear equations has a limit cycle or not. We introduce a method to first determine the boundedness of solution trajectories in such a way that the transformation to a Liénard system or the use of a Dulac function can be avoided. Once boundedness of trajectories has been established, the nature of the equilibrium points reduces to simple eigenvalue analysis. The Elemental Limit Cycle method (ELC) provides elementary criteria to evaluate the nature of the pivotal functions of a system which will indicate boundedness and may be applicable to more general models.

Modern Optics Simplified

This textbook is designed for use in a standard physics course on optics at the sophomore level. The book is an attempt to reduce the complexity of coverage found in Modem Optics to allow a student with only elementary calculus to learn the principles of optics and the modern Fourier theory of diffraction and imaging. Examples based on real optics engineering problems are contained in each chapter. Topics covered include aberrations with experimental examples, correction of chromatic aberration, explanation of coherence and the use of interference theory to design an antireflection coating, Fourier transform optics and its application to diffraction and imaging, use of gaussian wave theory, and fiber optics will make the text of interest as a textbook in Electrical and bioengineering as well as Physics. Students who take this course should have completed an introductory physics course and math courses through calculus Need for experience with differential equations is avoided and extensive use of vector theory is avoided by using a one dimensional theory of optics as often as possible. Maxwell’s equations are introduced to determine the properties of a light wave and the boundary conditions are introduced to characterize reflection and refraction. Most discussion is limited to reflection. The book provides an introduction to Fourier transforms. Many pictures, figures, diagrams are used to provide readers a good physical insight of Optics. There are some more difficult topics that could be skipped and they are indicated by boundaries in the text.

METHOD OF DIMENSIONALITY REDUCTION IN CONTACT MECHANICS AND FRICTION: A USER’S HANDBOOK. III. VISCOELASTIC CONTACTS

Until recently the analysis of contacts in tribological systems usually required the solution of complicated boundary value problems of three-dimensional elasticity and was thus mathematically and numerically costly. With the development of the so-called Method of Dimensionality Reduction (MDR) large groups of contact problems have been, by sets of specific rules, exactly led back to the elementary systems whose study requires only simple algebraic operations and elementary calculus. The mapping rules for axisymmetric contact problems of elastic bodies have been presented and illustrated in the previously published parts of The User's Manual, I and II, in Facta Universitatis series Mechanical Engineering [5, 9]. The present paper is dedicated to axisymmetric contacts of viscoelastic materials. All the mapping rules of the method are given and illustrated by examples.

A Bound on Partitioning Clusters

Let $X$ be a finite collection of sets (or "clusters"). We consider the problem of counting the number of ways a cluster $A \in X$ can be partitioned into two disjoint clusters $A_1, A_2 \in X$, thus $A = A_1 \uplus A_2$ is the disjoint union of $A_1$ and $A_2$; this problem arises in the run time analysis of the ASTRAL algorithm in phylogenetic reconstruction. We obtain the bound$$ | \{ (A_1,A_2,A) \in X \times X \times X: A = A_1 \uplus A_2 \} | \leq |X|^{3/p} $$where $|X|$ denotes the cardinality of $X$, and $p := \log_3 \frac{27}{4} = 1.73814\dots$, so that $\frac{3}{p} = 1.72598\dots$. Furthermore, the exponent $p$ cannot be replaced by any larger quantity. This improves upon the trivial bound of $|X|^2$. The argument relies on establishing a one-dimensional convolution inequality that can be established by elementary calculus combined with some numerical verification.In a similar vein, we show that for any subset $A$ of a discrete cube $\{0,1\}^n$, the additive energy of $A$ (the number of quadruples $(a_1,a_2,a_3,a_4)$ in $A^4$ with $a_1+a_2=a_3+a_4$) is at most $|A|^{\log_2 6}$, and that this exponent is best possible.

VON NEUMANN’S CONSISTENCY PROOF

We consider the consistency proof for a weak fragment of arithmetic published by von Neumann in 1927. This proof is rather neglected in the literature on the history of consistency proofs in the Hilbert school. We explain von Neumann’s proof and argue that it fills a gap between Hilbert’s consistency proofs for the so-called elementary calculus of free variables with a successor and a predecessor function and Ackermann’s consistency proof for second-order primitive recursive arithmetic. In particular, von Neumann’s proof is the first rigorous proof of the consistency of an axiomatization of the first-order theory of a successor function.