Performance Upgrade Research Articles

Applications of the Beijing IR-free electron laser facility

We report on the upgrade of the Beijing IR free electron laser (BFEL) facility, including improvements of the system stability, performance upgrade and optical wavelength range extension. Applications in the field of material sciences, such as the development of mid- and far-infrared detectors made from YBa 2Cu 3O 7 high T c thin films, and laser isotope separation, as well as applications in the life sciences, such as protein folding studies, and plant denaturation observations, are described.

High performance hybrid slow positron beam and its user application spectrum

A true hybrid beam is operational at PSI. From a β + radioisotope source and a premoderation of the positrons to medium energies in a high magnetic field confinement of Tesla order, a 3 keV wide spectrum of positrons is extracted and adiabatically guided to low fields of less than 100 G allowing extraction in a highly efficient and quasi-divergency-free way into field free space by increasing the positron's transverse energy spread by less than 20 eV. Double electrostatic focussing followed each time by W-remoderators (air lock anneal is possible) results in a beam diameter of μm dimensions. The microbeam is then transported through a cylindrical mirror beam switch device to five different user ports (one at a time, within minutes). The first target station is equipped with a retractable beam gun and a high precision sample manipulator with six movements for low (−200°C) and high (+950°C) temperatures (sample introduction by an air lock system). At the target chamber a UHV of 3.5 × 10 −11 mbar has been reached and the chamber can be equipped for surface physics experiments, for example to perform PAES. The sample is always at ground potential and the beam energy can be tuned between a few eV and 60 keV. The facility, initially equipped with a source of 500 mCi 58Co, produces a monoenergetic beam intensity (energy spread < 2 eV) at the target of 3 × 10 6 e +/s with an average transverse phase space corresponding to 100 μm × 50 mrad. In one of the user ports an optional 7 mm diameter beam of intensity 10 7 e +/s will be available. Initial beam experiments and possible applications will be discussed and the full potential of beam performance up-grade (intensity > 10 10 e +/ s, pulsing, repolarization) will be outlined.

Optimum CFAR detection against compound Gaussian clutter with partially correlated texture

The paper deals with CFAR detection in compound Gaussian clutter with a partially correlated texture component. A theoretical high performance upgrade has been demonstrated using the ideal exact knowledge of this component in the CFAR scheme ('ideal CFAR') in a paper by Watts (1985) for K-distribution. For practical application the authors derive some optimum local texture estimators, based on the closest range cells: and use the estimated values to set the detection threshold. The schemes differ for operating over the intensity or the logarithm and for using or not prior information about the texture correlation. In particular, a maximum a posteriori estimator is derived, which outperforms the usual cell averaging CFAR and provides always performance close to the 'ideal CFAR'. The derivations are valid for all compound Gaussian clutters. The performances obtained with K and compound weibull distribution are compared, assessing the robustness of the proposed detection scheme.

3.5.2 SYSTEMS ENGINEERING FLOWDOWN ON THE F‐15 PROGRAM

AbstractSystems Engineering defines a disciplined design and verification process for developing systems. Its iterative and balanced approach results in systems that meet all of their intended needs and satisfy all of their intended customers. McDonnell Douglas Aerospace (MDA) is implementing Systems Engineering across the enterprise, including mature systems such as the F‐15 Weapon System.The F‐15 Program has taken Systems Engineering and tailored it to support new development activity. The F‐15 Program expects to improve product reliability and maintainability, develop performance upgrades, and improve the producibility of the F‐15 Weapon System by applying a disciplined Systems Engineering process to selected elements of the system.The F‐15 Program is expanding its Systems Engineering approach as part of its Integrated Product Development organization. This paper describes MDA's Systems Engineering process, the tailored F‐ 15 Program implementation approach, and progress to date.

Evolution of a narrowband exchange toward broadband

Today's telecommunications network is facing a continuing evolution, driven by the growing interest and demand for services requiring higher bandwidth and flexibility of transport. Replacing a narrowband switch fabric with a broadband switch fabric allows the operator to reuse existing narrowband hardware and software, while adding new capabilities such as SDH and ATM, making performance and capacity upgrades possible. >

From JANET to SuperJANET

Abstract JANET is a national backbone network which provides data communications services for the UK Higher Education and Research Community. The network is operated under the authority of the Secretary of State at the Department of Education and Science. Funding is provided by a number of agencies among which the Computer Board takes lead responsibility. The aim of the network is to provide a unified and pervasive communications infrastructure capable of supporting a wide range of academic and research activities. The principle of open communications based on non-proprietary standards has been the foundation of the network since its inception. The network currently serves nearly 200 sites, one third of which are connected at 64 kbps. The JANET MK II programme is a performance upgrade with the objective of providing network access at 2 Mbps for more than 50 sites, and part of this upgrade is already in service. The longer term plans envisage the development of a SuperJANET with a major increase in the both the scope of the network and its performance. SuperJANET will be a broadband network capable of supporting new styles of communication such as multi-media and video and offering new opportunities for research and education. SuperJANET will also offer a testbed to support IT research activities and the close association between research and service networks will accelerate the development of new network services based on the results of UK and European IT Research.

Performance calculations for battery power supplies as laboratory research tools

The design and construction of a battery power supply (BPS) capable of providing several megaamperes of current for several seconds are described. This system consists of six modules (each containing 2288 automotive batteries) which may be connected in two different series-parallel arrangements. The electrical characteristics of the BPS are defined at the component level. The characterization is done theoretically and through the examination of experimental results. A mathematical model of the BPS is developed which contains a variety of potential upgrade options. The BPS model is then coupled to an existing railgun simulation code. This combined model is used to investigate a variety of topics as they relate to electromagnetic launcher laboratory power supplies. Potential railgun performance versus candidate BPS upgrade options are studied. >

The CESR computer control system

The control system for the Cornell Electron Storage Ring (CESR) has functioned satisfactorily since its implementation in 1979. Key characteristics are fast tuning response, almost exclusive use of FORTRAN as a programming language, and efficient coordinated ramping of CESR guide field elements. This original system has not, however, been able to keep pace with the increasing complexity of operation of CESR associated with performance upgrades. Limitations in address space, expandability, access to data system-wide, and program development impediments have prompted the undertaking of a major upgrade. The system under development accommodates up to 8 VAX computers for all applications programs. The database and communications semaphores reside in a shared multi-ported memory, and each hardware interface bus is controlled by a dedicated 32 bit micro-processor in a VME based system.

The relationship between the chemical structure of ester base fluids and their influence on elastomer seals, and wear characteristics

AbstractThe intention of this paper is to examine the relationship between the chemical structure of ester base fluids and their influence on elastomer seals and wear characteristics. It presents background information about esters, some of which can be considered as blending components for mineral oil and/or polyalphaolefins, while others have properties so similar to mineral oil that in principle substitution is possible. It examines the effects of ester base fluids on a number of properties of elastomers, including modulus, tensile strength, elongation at break, hardness, and volume changes. It also explains a method of selecting synthetic base fluids for performance upgrading or viscosity purposes, using a ‘non‐polarity index’ which allows more speedy comparison and selection of ester base fluids.

ACCELERATING AGRICULTURAL DEVELOPMENT THROUGH CO-OPERATIVES

ABSTRACT A successful co-operative movement has been shown to be one of the ways of transforming subsistence-orientated agriculture into commercial agriculture. It should not be inferred from this that the formation of agricultural co-operatives alone will achieve the goals of agricultural development. However, they may act as catalysts in the process of agricultural development. The co-operative movement in the national states of Southern Africa has not yet, with some rare exceptions, played a significant role in the upgrading of agricultural performance. The aim of this paper of performance of the co-operative movement in agriculture in the less developed national states. Proposals are made as to— (a) the functional role of the co-operatives in agricultural development; and (b) the ubstitutionalisation of co-operative action in the national states.

Application of Distributed Computer Control Systems to Modernization of Metal Rolling Mills

This paper treats the application of distributed computer control systems technology to modernize and upgrade existing steel plate and strip production facilities. This technology is ideally suited to improve the performance of plate mills, hot strip mills and cold strip mills. First, the processes themselves are distributed geographically. A hot strip mill may extend over one kilometer. Second, functional distribution is already practiced and proven. Hot strip process machinery is enormous and expensive. A new greenfield world market competitive computer controlled hot strip production facility may cost $500 million (USA). Yet even a 30 year-old hot strip mill has high investment and high throughput values. Daily throughput is approximately (USA) $l/day per tonne/year, usually more than $1, 000, 000/day. A modernization and performance upgrade of such a mill is a sound investment, and one that optimizes the use of limited capital resources. Most important, steel physical properties and dimensional qualities can, on most mills, be improved to meet world market requirements. Experiences with such programs exist and may be used to plan the project and forecast performance. The paper discusses application of computers, microprocessors, data highways and the man-machine interface to upgrade hot strip mills utilizing pre-solid state electronics technology. System hierarchies suitable for step-by-step implementation are presented. Since there is no single correct structure, several system structures are discussed. Examples of the use of microprocessors in the distributed control system are presented. Application of distributed computer control system technology to upgrade existing metal rolling mill facilities is a cost effective method to improve steel product physical characteristics and dimensional qualities and to transfer new technology to developing countries.

Professionalization of Document Examiners: Problems of Certification and Training

Abstract The entire forensic science field is experiencing an onslaught of pressures, both from within and without, calling for an upgrading of skills, improving education, and performance and eventual professionalization of its practitioners. Part of the stimulus for change is generated by the courts, where recent reorganizations and decisions will have a direct effect on all document examiners. The U.S. Supreme Court issued new rules of evidence for the Federal Court system during the October 1972 term. These rules became effective July 1, 1973 [1].