Advanced Solar Power Systems

The Advanced Solar Power System (ASPS) concentrator uses a technically sophisticated design and extensive tooling to produce very efficient (80 to 90%) and versatile energy supply equipment which is inexpensive to manufacture and requires little maintenance. The advanced optical design has two 10th order, generalized aspheric surfaces in a Cassegrainian configuration which gives outstanding performance and is relatively insensitive to temperature changes and wind loading. Manufacturing tolerances also have been achieved. The key to the ASPS is the direct absorption of concentrated sunlight in the working fluid by radiative transfers in a black body cavity. The basic ASPS design concepts, efficiency, optical system, and tracking and focusing controls are described

The EMC of satellite power systems and DoD C-E systems

The solar power satellite (SPS) technical parameters that are needed to accurately assess the electromagnetic compatibility (EMC) between SPS systems and DoD communications-electronics (C-E) systems are identified and assessed. The type of electromagnetic interactions that could degrade the performance of C-E systems are described and the major military installations in the southwestern portions of CONUS where specially sensitive C-E systems are being used for combat training and evaluation are identified. Classes of C-E systems that are generally in the vicinity of these military installations are considered. The Technical parameters that govern the degree of compatibility of the SPS with these C-E systems, and some technical requirements that are necessary to ensure short-term and long-term EMC are identified

A new camera for high-resolution infrared imaging of works of art

A new camera – SIRIS (scanning infrared imaging system) – developed at the National Gallery in London allows high-resolution images to be made in the near infrared region (900–1700 nm). The camera is based on a commercially available 320 × 256 pixel indium gallium arsenide area array sensor. This relatively small sensor is moved across the focal plane of the camera using two orthogonal translation stages to give images of c. 5000 × 5000 pixels. The main advantages of the SIRIS camera over scanning infrared devices or sequential image capture and mosaic assembly are its comparative portability and rapid image acquisition – making a 5000 × 5000 pixel image takes less than 20 minutes. The SIRIS camera can operate at a range of resolutions; from around 2.5 pixels per millimetre over an area of up to 2 × 2 m to 10 pixels per millimetre when examining an area measuring 0.5 × 0.5 m. The development of the mechanical, optical and electronic components of the camera, including the design of a new lens, is described. The software used to control image capture and to assemble the individual frames into a seamless mosaic image is mentioned. The camera was designed primarily to examine underdrawings in paintings; preliminary results from test targets and paintings imaged in situ are presented and the quality of the images compared with those from other cameras currently used for this application

The Future of Employment: Purposive Interpretation and the Role of Contract after Uber

A person's entitlement to workplace rights and protections under English law is conditional on their relationship falling within the legal category of employment, by virtue of them having the requisite status. The employment status of individuals performing on-demand work via digital platforms is particularly contentious and has been a focal point for debate in recent years. The Supreme Court decision in Uber BV v Aslam represents a ground-breaking judgment on this issue, which has radical implications for the correct approach to determining employment status more generally. It is argued here that, while leaving some important questions unanswered, the purposive and relational approach to employment status developed by the Supreme Court in Uber BV v Aslam is to be welcomed, and that this new approach has far-reaching consequences for the future of the legal category of employment

SIRIS: a high resolution scanning infrared camera for examining paintings

The new SIRIS (Scanning InfraRed Imaging System) camera developed at the National Gallery in London allows highresolution images of paintings to be made in the near infrared region (900–1700 nm). Images of 5000 × 5000 pixels are made by moving a 320 × 256 pixel InGaAs array across the focal plane of the camera using two orthogonal translation stages. The great advantages of this camera over scanning infrared devices are its relative portability and that image acquisition is comparatively rapid – a full 5000 × 5000 pixel image can be made in around 20 minutes. The paper describes the development of the mechanical, optical and electronic components of the camera, including the design of a new lens. The software routines used to control image capture and to assemble the individual 320 × 256 pixel frames into a seamless mosaic image are also mentioned. The optics of the SIRIS camera have been designed so that the camera can operate at a range of resolutions; from around 2.5 pixels per millimetre on large paintings of up to 2000 × 2000 mm to 10 pixels per millimetre on smaller paintings or details of paintings measuring 500 × 500 mm. The camera is primarily designed to examine underdrawings in paintings; preliminary results from test targets and paintings are presented and the quality of the images compared with those from other cameras currently used in this field

Multi-camera digital holographic PIV: Tomographic DHPIV

The wide scale application of digital holographic particle image velocimetry (DHPIV) as a three-component three-dimensional (3C-3D) velocity field measurement tool is current restricted by the limited size and resolution of commercially available CCD arrays, resulting in a elongation of particle is the direction normal to the hologram plane. This elongation can be over an order of magnitude greater than the true particle diameter and posses significant problems for the cross-correlation analysis used in particle image velocimetry (PIV). In this paper we discuss a multi-camera method of tomographic digital holographic particle image velocimetry (Tomo-DHPIV) to reconstruct a 3D intensity field without a loss of resolution in the hologram normal direction. Application of this reconstruction technique is provided along with Monte Carlo simulations of the effects of various operating parameters

Algebraic Reconstruction Techniques for Tomographic Particle Image Velocimetry

Tomographic particle image velocimetry (Tomo-PIV) is a technique for three-component three-dimensional (3C-3D) velocity measurement based on the tomographic reconstruction of a volume intensity field from multiple two-dimensional projection. As such the performance and accuracy of this technique is highly dependant on the algorithm used for reconstruction. This paper presents an evaluation of four different tomographic reconstruction algorithms, namely multiplicative algebraic reconstruction techinique (MART); adaptive algebraic reconstruction technique (AART); improved iterative algorithm for sparse object reconstruction (IIASOR); and simultaneous iterative reconstruction technique (SIRT). Results indicate that the MART and AART algorithms provide considerably better particle field reconstructions for fewer iterations