Small-body encounters using solar sail propulsion

Cometary Rendezvous and Flybys have large V requirements, which impose almost unattainable, and sometimes prohibitive, demands on the propellant budget of conventional, chemical propulsion. Ion Propulsion is a viable alternative, but as the number and difficulty of target objectives increases then the potential of this technology becomes rapidly less attractive. Solar sails exhibit an extremely high effective specific impulse over long mission durations. No propellant is required so that large changes in V could be realised without necessitating the introduction of complex gravity assists, which prolong mission duration and restrict launch opportunities. The endurance of the structures and materials are thus the only limiting factors dictating the number and range of bodies with which the solar-sail propelled vehicle can encounter throughout its lifetime. In this paper we have analysed a number of high-energy, small-body mission scenarios using a parameterised approach to sail control representation. The sail cone and clock angle histories were characterised by linear interpolation across a set of discrete nodes. The optimal control problem was thus transcribed to a Non-Linear Programming problem to select the optimal controls at the nodes that minimised the transfer time while enforcing the cartesian end-point boundary constraints (6 states for rendezvous, 3 for flypast). The Fortran77 optimisation package NPSOL 5.0 was used for this purpose with the variational equations of motion formulated in modified equinoctial orbital elements and integrated using a variable-order, adaptive step-size Adams-Moulton-Bashforth method. We present optimal rendezvous trajectories to Short-Period Comets such as 46P/Wirtanen in 484 days with a sail characteristic acceleration of 1.9 mms-2, and with 2P/Encke in 574 days with a characteristic acceleration of 1.0 mms-2. An analysis using high-performance sails has been conducted to permit fast flyby intercepts of newly discovered Long Period Comets (LPCs). Previous examples adopted were C/1995 O1/Hale- Bopp, C/1995 Y1/Hyakutake, C/1999 T1/McNaught-Hartley, C/1999 F1/Catalina, C/1999 N2/Lynn and C/1999 H1/Lee, to demonstrate the feasibility of a late launch to quickly intercept a new LPC using a solar sail. Since the time between discovery of a new LPC such as Hale-Bopp and perihelion passage was less then 2 years, this then leaves a very short time-span for orbit determination, preparation, planning and operational phases. Preliminary mission analysis shows that a Hale-Bopp perihelion flypast could have been achieved, with a sail characteristic acceleration of 5.0 mms-2, by launching just 209 days before comet perihelion passage. With a characteristic acceleration of 2.0 mms-2 Hale-Bopp could also have been intercepted at its descending node by launching 270 days before nodal descent. The sail could then have returned to rendezvous with the Earth 261 days later, giving a minimum total mission turn-around time of 531 days. An alternative, dual flyby scenario has been investigated, to continue on to C/1997 D1/Mueller, after which solar system escape was reached and arrival at Heliopause would occur in 12 years. Solar Electric Propulsion has been adopted as the primary propulsion system for the DAWN dual asteroid rendezvous mission scheduled for launch in 2006. The objective of this mission is to rendezvous with inner main-belt asteroids, Vesta and Ceres. We have also investigated solar sail adaptation to this mission, for the same launch date and 11 month orbiter stay-times. We have extended the mission objectives to two further asteroids, Lucina and Lutetia, with the aim of demonstrating a Mainbelt Asteroid Survey scenario

Construction subcontracts: for what we are about to receive

This paper is from a study on specialist and trade contracting in the construction industry. The research was commissioned by CIRIA and undertaken by the University of Reading in conjunction with Sir Alexander Gibb & Partners Ltd. The purpose of the work was to provide guidance for effective and equitable practice in the management of projects where much of the work is executed, and possibly designed, by specialist and trade contractors (STCs). As part of this study, a preliminary investigation into the nature and origins of specialist contracting was undertaken, in conjunction with a survey of the problems confronting STCs. This paper presents that phase of the project

AStudy of Training and Development (T&D) in the Irish Financial Services Sector

The proliferation of reports on ‘lifelong learning’ in recent years has brought to the fore the importance of workplace learning. In the present knowledge economy companies with highly knowledgeable and skilled employees have a competitive edge and organisational competitiveness has a direct effect on national competitiveness. The findings of recent reports (McIvor 2004; Chisholm et al 2004; NCPP 2005) suggest that the Republic of Ireland ranks poorly in relation to her European neighbours when it comes to adult participation in lifelong learning. Additionally, out of 15 EU countries, learning in the workplace is least popular in Ireland (Chisholm et al 2004). These findings are quite worrying as Ireland’s attractiveness to Foreign Direct Investment (FDI) is being slowly eroded due to high labour costs, vat rates and carbon taxes. Additionally, many countries have now introduced, or are planning to offer, lower corporation tax, a major attraction of Ireland to Multi-National Corporations (MNCs) in recent decades. However, many organisations are primarily attracted to Ireland’s highly educated and skilled workforce and it is important that we remain competitive in this regard. For this reason it is essential that lifelong learning is encouraged. The workplace is central in this regard and Human Resource Development (HRD) departments have a primary responsibility in ensuring that individuals are trained and developed. However, the research conducted on Training and Development (T&D) is focused primarily on management and not employees – recipients of T&D. This may explain the lacuna of research into the effectiveness of T&D in organisations, as information about T&D spend and the techniques used does not help in assessing effectiveness. This study chooses to take a holistic approach (in focusing on various levels of employees) to T&D in the Irish Financial Services Sector and consists of four research objectives. These objectives seek to ascertain the importance placed on T&D, to assess the various T&D approaches used to determine the drivers and barriers to employee involvement in T&D. The effectiveness of T&D in one organisation (Company A) is also assessed. There are a number of interesting findings to the study, and the results reflect positively on the respondent companies and on Company A, particularly from an employee point of view. These findings are presented in Chapter Eight and suggestions for industry and government, along with recommendations for further research, are outlined in Chapter Nine

The Capture of Mametz Wood: A Study of Lloyd George's "Welsh Army" at the Battle of the Somme 1916

The Battle of the Somme, 1916, provided a severe and bloody test for the inexperienced units of Kitchener's 'new' volunteer armies, among them the 38th (Welsh) Division which had been raised by Lloyd George in 1914 in an ambitious, but unsuccessful, attempt to create a Welsh Army Corps of two divisions. The Welsh Division went to France in December 1915 under the command of Major General Ivor Philipps, Liberal MP and political acquaintance of Lloyd George. The division's early training had given it the appearance of a smart, well disciplined force and both the divisional commander and Lloyd George were confident that it would distinguish itself in battle. After six months in the trenches near Neuve Chappelle, the division marched to the Somme where, for its first major attack it was given the formidable task of capturing Mametz Wood, on rising ground between the German first and second lines. This wood, the largest on the Somme, was defended by regular troops and reservists of the 3rd Guards Division, the cream of Germany's highly professional army. The Welsh Division, by contrast, consisted of wartime volunteers, unskilled in offensive tactics, untrained in woodland fighting. A half-hearted first attack failed, as much the result of poor handling from above as of German opposition, Philipps was relieved of his command. At the second attempt, the division captured the wood after two days bitter fighting. But its performance did not satisfy the Corps commander and the division emerged from the battle with an indifferent reputation - which was not shaken off until the division had proved its worth at Pilckem Ridge in 1917. This study examines the difficulties which it faced at Mametz Mood, and shows that the Welsh Division did remarkably well, without getting the credit it deserved

Messages from the Oracle: Assessing the Impact of Major In-Town Shopping Centres

Planning policy aimed at preserving the viability of UK town centres halted the wave of out-of-town shopping centres – Schiller’s “third wave” of decentralisation. In consequence,  a number of major in-town shopping malls were developed in the UK. The first of these was the Oracle Centre in Reading. This paper examines the impact of the Oracle on retail activity in the town centre using land use data and the results of a retailer survey. The Oracle acted as a catalyst for change, accelerating trends already observed in the centre, shifting the prime pitch, weakening peripheral areas and increasing turnover rates. The added attraction of the town centre offset many of the trade diversion impacts. However, some adverse effects may have been masked by strong consumer spending and a vibrant local economy.In-town Shopping, Out-of-town Shopping, Retail, Shopping Malls, Retail Activity

Marine protected areas

The oceans and seas under Australian jurisdiction include the full range of ocean temperature zones, from tropical to polar, ranging from the spectacular coral reefs of the tropical north to the majestic kelp forests of the temperate south. This environmental diversity explains the rich variety of life found in Australia’s oceans. Australia\u27s marine environments contain more than 4,000 fish varieties and tens of thousands of species of invertebrates, plants and micro-organisms. Large areas have been little explored and new species are often discovered. Scientists estimate that about 80% of the species in Australia’s southern oceans occur nowhere else in the world. This paper looks at competing uses of the oceans, threats and regulatory arrangements

The genetic architecture underlying the evolution of a rare piscivorous life history form in brown trout after secondary contact and strong introgression

Identifying the genetic basis underlying phenotypic divergence and reproductive isolation is a longstanding problem in evolutionary biology. Genetic signals of adaptation and reproductive isolation are often confounded by a wide range of factors, such as variation in demographic history or genomic features. Brown trout ( ) in the Loch Maree catchment, Scotland, exhibit reproductively isolated divergent life history morphs, including a rare piscivorous (ferox) life history form displaying larger body size, greater longevity and delayed maturation compared to sympatric benthivorous brown trout. Using a dataset of 16,066 SNPs, we analyzed the evolutionary history and genetic architecture underlying this divergence. We found that ferox trout and benthivorous brown trout most likely evolved after recent secondary contact of two distinct glacial lineages, and identified 33 genomic outlier windows across the genome, of which several have most likely formed through selection. We further identified twelve candidate genes and biological pathways related to growth, development and immune response potentially underpinning the observed phenotypic differences. The identification of clear genomic signals divergent between life history phenotypes and potentially linked to reproductive isolation, through size assortative mating, as well as the identification of the underlying demographic history, highlights the power of genomic studies of young species pairs for understanding the factors shaping genetic differentiation

Internet censorship and mandatory filtering

This paper outlines the current debate over the Commonwealth Government\u27s filtering scheme for internet content and the practice of governments in other countries. It concludes: \u27With the limited exceptions of Germany and Italy, mandatory ISP level filtering is not a feature of any of the countries reviewed. In place, rather, are voluntary ISP filtering schemes designed to prevent accidental access to a defined list of illegal sites containing child pornography. However, in the UK the position seems to be that the internet industry is encouraged to participate in this scheme, under threat of regulatory intervention should it fail to do so. The line between mandatory and voluntary participation is not clear-cut.\u2