Simulation tools are playing an increasingly important role in materials science and engineering and beyond their well established importance in research and development, these tools have a significant pedagogical potential. We describe a set of online simulation tools and learning modules designed to help students explore important concepts in materials science where hands-on activities with high-fidelity simulations can provide insight not easily acquired otherwise. The online tools, which involve density functional theory and molecular dynamics simulations, have been designed with non-expert end-users in mind and only a few clicks are required to perform most simulations, yet they are powered by research-grade codes and expert users can access advanced options. All tools and modules are available for online simulation in nanoHUB.org and access is open and free of charge. Importantly, instructors and students do not need to download or install any software. The learning modules cover a range of topics from electronic structure of crystals and doping, plastic deformation in metals, and physical properties of polymers. These modules have been used in several core undergraduate courses at Purdue’s School of Materials Engineering, they are self contained, and are easy to incorporate into existing classes.

The drive to reduce the thickness of solar cells is putting ever greater demands on light-trapping techniques. Techniques are required to improve absorption of light within the semiconductor, while not adversely affecting the electrical properties of the device. Conventional diffraction gratings can scatter visible and near-infrared photons into large angles, which get trapped in the silicon layer by total internal reflection. However, diffraction gratings typically have large feature sizes and so increase the overall surface area of a solar cell compared to the planar case. A periodic arrangement of metal nanoparticles acts as a diffraction grating, but an over-coated semiconductor will have a similar surface area to a planar layer due a combination of a low particle height and low surface coverage.

Random arrays of identical metal nanoparticles feature Lorentzian scattering peaks that can be tuned by modifying the size and shape of the particle. Periodic arrays have much more complicated scattering peaks, due to the enhancement and suppression of scattering at different wavelengths caused by the constructive and destructive interference between each nanoparticle. In effect the scattering spectrum of the individual nanoparticle is modified by the diffractive orders of the array, and so both parameters must be optimized together.

We have studied periodic arrays of metal nanoparticles fabricated using electron-beam lithography, and characterised their reflectance properties. The optical properties of the fabricated arrays were found to be in good agreement with finite-difference time-domain (FDTD) simulations. Au and Al nanoparticles are found to have a strong scattering effect and Al nanoparticles are also shown to exhibit an anti-reflection effect in combination with scattering. This work is focused on verifying that FDTD simulations can accurately model metal nanoparticle arrays and then extending the simulations to determine the previously unknown transmittance characteristics of metal nanoparticle arrays on silicon.

Antechinus agilis mate within a 2–3 week, highly synchronized period each year, with copulation consisting of short bouts of thrusting interrupted by longer bouts of rest during which time the male remains mounted. In the laboratory, mating can last as long as 8–12 h without any break in intromission, with captive paired animals generally copulating once per day (Woolley, 1966a,b). The mating programme used in this study examines the effects on copulatory behaviour of changing: (1) timing of access relative to ovulation; (2) order of mating; (3) the delay between the first and second males' mating access. The total mount time was divided into quarters and the changes in behavioural patterns assessed by examining changes in the frequency of five key activities; thrusting, pelvic side-to-side movements, walking, female resistance, and dismounts. No significant differences were observed in the time from initial pairing to first mount regardless of mating order or time of mating, nor was the total time mounted significantly affected by mating order. Significant reductions in the total time mounted were evident, however, for those males mating closer to the time of ovulation. The behavioural strategies associated with copulation in A. agilis significantly enhance arguments for equality between males and females in determining overall mating strategies.

The Grunsky inequalities [6] and their generalizations (e.g., [5; 14; 17]) have become an increasingly important tool for the study of the coefficients of normalized univalent functions defined on the unit disc. In particular, proofs based upon the Grunsky inequalities have now settled the Bieberbach conjecture for the fifth [15] and sixth [13] coefficients. For bounded univalent functions the situation is similar, although the Grunsky inequalities go over to those of Nehari [11].

Since 1948, there has been a marked revival of interest in the presidential primary. In all probability this has come about because of the cleavage between the bulk of the regular Republican leadership, most of whom favored Taft, and the rank and file of the Republican party, who, together with many independent voters, favored Eisenhower. Concurrently, in the Democratic party there was in 1952 a “free convention” for the first time since 1932. As a result, there was revived interest in the presidential primary, and in the system of selecting delegates to the national nominating conventions, during the preconvention campaigns of 1952. Since the untimely heart attack suffered by President Dwight D. Eisenhower in 1955, interest in the nominating process for the presidential candidates of the major parties is again at a high point. This article, after reviewing briefly recent developments with respect to presidential primaries, discusses in some detail the legislation enacted in 1955 by the state of Florida.

During the period of the 1952 contest, interest in the presidential primary was expressed in four ways. In the first place, Eisenhower's decisive show of strength in primary contests in New Hampshire, Minnesota, and New Jersey drew public attention to the contrast between the preference primary and the methods of delegate selection in other states. Texas is a prime example of the manipulations that characterized the worst use of the convention system.