Qualified to exploit? : some thoughts on the social responsibility of business : inaugural lecture delivered at Rhodes Unversity

Inaugural lecture delivered at Rhodes UniversityRhodes University Libraries (Digitisation

Optical Yagi-Uda nanoantennas

Conventional antennas, which are widely employed to transmit radio and TV signals, can be used at optical frequencies as long as they are shrunk to nanometer-size dimensions. Optical nanoantennas made of metallic or high-permittivity dielectric nanoparticles allow for enhancing and manipulating light on the scale much smaller than wavelength of light. Based on this ability, optical nanoantennas offer unique opportunities regarding key applications such as optical communications, photovoltaics, non-classical light emission, and sensing. From a multitude of suggested nanoantenna concepts the Yagi-Uda nanoantenna, an optical analogue of the well-established radio-frequency Yagi-Uda antenna, stands out by its efficient unidirectional light emission and enhancement. Following a brief introduction to the emerging field of optical nanoantennas, here we review recent theoretical and experimental activities on optical Yagi-Uda nanoantennas, including their design, fabrication, and applications. We also discuss several extensions of the conventional Yagi-Uda antenna design for broadband and tunable operation, for applications in nanophotonic circuits and photovoltaic devices

Analysis of the transport infrastructure of the Cape Midlands and Karoo regions

From Preface: In 1966, the Karroo Development Association approached Rhodes University to undertake a socio-economic survey of their region. This survey was to form the basis for development planning in view of the expected benefit to the region of the Orange River Project. Similar requests were also received from the Midlands Planning Association and the South Eastern Areas Development Association. When Rhodes University consulted the Department of Planning, which strongly supported the principle of a regional survey, it was decided that, although Port Elizabeth and its hinterland comprised a logical economic unit, the area should be sub-divided. The University of Port Elizabeth was entrusted with the responsibility for an analysis of the metropolitan area, while the Institute of Social and Economic Research of Rhodes University was commissioned to undertake a socio-economic survey of the inland areas. This thesis on the transport infrastructure of the Cape Midlands and Karroo Regions represents one aspect of the survey

Electro-optical switching by liquid-crystal controlled metasurfaces

We study the optical response of a metamaterial surface created by a lattice of split-ring resonators covered with a nematic liquid crystal and demonstrate millisecond timescale switching between electric and magnetic resonances of the metasurface. This is achieved due to a high sensitivity of liquid-crystal molecular reorientation to the symmetry of the metasurface as well as to the presence of a bias electric field. Our experiments are complemented by numerical simulations of the liquid-crystal reorientation.Comment: 6 pages, 3 figure

An investigation into the influence of the physical distribution concept on the performance of certain South African manufacturers of consumer products

The "Physical Distribution Concept" is being increasingly recognised as a vitally important business philosophy for those firms for which efficient physical distribution is critical to marketing success. Manufacturers of products which are perishable, easily substitutable; and/or quickly obsolescent are some which fall into this category. In a competitive business environment, factors such as the " availability" of the product, and not simply its price or quality, begin to exert a significant influence on the purchasing decision. The "Physical Distribution Concept" comprises three elements, namely, consumer orientation; organizational integration and profit orientation. "Physical Distribution Orientation" refers to the predisposition of the firm and its employees to these three elements. For the Physical Distribution Concept to serve as an effective guide to management action, a physical distribution orientation on the part of all those concerned with marketing and physical distribution-related activities in a firm, is a pre-requisite. The chief executive, in particular, should adhere to this business philosophy, regardless of the functional route he followed to his position. In his leadership role, theory holds that he exerts considerable influence on his subordinates, and consequently on his firm's way of doing business. This thesis is concerned with an analysis of the Physical Distribution Concept. It focuses on the chief executives of firms manufacturing consumer convenience goods, as well as consumer shopping goods. As such, it is primarily concerned with determining the extent to which the chief executives are physical distribution oriented and whether there is a statistically significant relationship between their extent of physical distribution orientation and their companies' performance. The thesis is also concerned with the extent to which any pattern of organizational arr angements for physical distribution exists

Enhancing Eu3+ magnetic dipole emission by resonant plasmonic nanostructures

We demonstrate the enhancement of magnetic dipole spontaneous emission from Eu3?ions by an engineered plas-monic nanostructure that controls the electromagnetic environment of the emitter. Using an optical microscope setup, an enhancement in the intensity of the Eu3?magnetic dipole emission was observed for emitters located in close vicinity to a gold nanohole array designed to support plasmonic resonances overlapping with the emission spectrum of the ions

GREGOR, a 1.5 m Gregory-type telescope for solar observation

GREGOR is a high-resolution solar telescope with an aperture of 1.5 m. It will be equipped with an adaptive optics system and is designed for high-precision measurements of magnetic fields and plasma motions in the solar atmosphere and chromosphere with a resolution of 70 km on the Sun. GREGOR will replace the 30 years old Gregory Coude Telescope at the Observatorio del Teide on Tenerife. We describe the optical design and the focal plane instrumentation. In concert with the other solar telescopes at Teide Observatory it will be useful for studying the dynamics of the solar atmosphere and of the underlying processes. GREGOR will also serve as a test bed for next-generation solar telescopes

The First Detections of the Extragalactic Background Light at 3000, 5500, and 8000A (II): Measurement of Foreground Zodiacal Light

We present a measurement of the absolute surface brightness of the zodiacal light (3900-5100A) toward a fixed extragalactic target at high ecliptic latitude based on moderate resolution (~1.3A per pixel) spectrophotometry obtained with the du Pont 2.5m telescope at Las Campanas Observatory in Chile. This measurement and contemporaneous Hubble Space Telescope data from WFPC2 and FOS comprise a coordinated program to measure the mean flux of the diffuse extragalactic background light (EBL). The zodiacal light at optical wavelengths results from scattering by interplanetary dust, so that the zodiacal light flux toward any extragalactic target varies seasonally with the position of the Earth. This measurement of zodiacal light is therefore relevant to the specific observations (date and target field) under discussion. To obtain this result, we have developed a technique that uses the strength of the zodiacal Fraunhofer lines to identify the absolute flux of the zodiacal light in the multiple-component night sky spectrum. Statistical uncertainties in the result are 0.6% (1 sigma). However, the dominant source of uncertainty is systematic errors, which we estimate to be 1.1% (1 sigma). We discuss the contributions included in this estimate explicitly. The systematic errors in this result contribute 25% in quadrature to the final error in our coordinated EBL measurement, which is presented in the first paper of this series.Comment: Accepted for publication in ApJ, 22 pages using emulateapj.sty, version with higher resolution figures available at http://www.astro.lsa.umich.edu/~rab/publications.html or at http://nedwww.ipac.caltech.edu/level5/Sep01/Bernstein2/frames.htm