4,436 research outputs found
Equiangular lines in Euclidean spaces
We obtain several new results contributing to the theory of real equiangular
line systems. Among other things, we present a new general lower bound on the
maximum number of equiangular lines in d dimensional Euclidean space; we
describe the two-graphs on 12 vertices; and we investigate Seidel matrices with
exactly three distinct eigenvalues. As a result, we improve on two
long-standing upper bounds regarding the maximum number of equiangular lines in
dimensions d=14, and d=16. Additionally, we prove the nonexistence of certain
regular graphs with four eigenvalues, and correct some tables from the
literature.Comment: 24 pages, to appear in JCTA. Corrected an entry in Table
Ammonium nitrate blasting agent (ANFO) for land clearing
The introduction of prilled AN has revolutionised explosives practice and made possible safer and cheaper methods of blasting.
This article outlines the methods of handling and using ANFO blasting agent for land clearing
Regulations for farm storage of fuels
THE Flammable Liquids Regulations, made under the Explosives and Dangerous Goods Act, are now the only comprehensive rules which apply to all industrial fuels and solvents and to all storages, from small tanks or drum depots to large industrial installations
Blasting with ammonium nitrate
THE mixture of ammonium nitrate prills with 6 per cent, of distillate fuel oil, known as ANFO , is now widely used for blasting in dry ground.
Farmers and clearing contractors use ANFO for stump-blasting, dam sinking and timber clearing
Blasting. Part 1. Explosives and the farmer
ABOUT 3,000 tons of commercial blasting explosives of various types are used every year in Western Australia of which approximately two thirds is utilised by mining industries and the remainder goes mainly to quarrying and public works.
The farmer and orchardist actually use only very small amounts but nevertheless explosives are a very useful working tool for the primary producer
Co-located wave and offshore wind farms: A preliminary approach to the shadow effect
In recent years, with the consolidation of offshore wind technology and the progress carried out for wave energy technology, the option of combine both technologies has arisen. This combination rest mainly in two main reasons: in one hand, to increase the sustainability of both energies by means of a more rational harnessing of the natural resources; in the other hand, to reduce the costs of both technologies by sharing some of the most important costs of an offshore project. In addition to these two powerful reasons there are a number of technology synergies between wave and wind systems which makes their combination even more suitable. Co-located projects are one of the alternatives to combine wave-wind systems, and it is specially for these project were so-called shadow effect synergy becomes meaningful. In particular, this paper deals with the co-location of Wave Energy Conversion (WEC) technologies into a conventional offshore wind farm. More specifically, an overtopping type of WEC technology was considered in this work to study the effects of its co-location with a conventional offshore wind park. This study aims to give a preliminary approach to the shadow effect and its implications for both wave and offshore wind energies
Blasting. Part 2. Explosives on the farm
EXPLOSIVES will function with maximum reliability and efficiency only when they are carefully stored under cool, dry conditions so as to avoid deterioration.
When preparing charges the user should follow a correct procedure and use the proper tools. Always treat explosives with respect and remember they are made to explode. When they hit they hit hard
CO-LOCATED WAVE AND OFFSHORE WIND FARMS: A PRELIMINARY CASE STUDY OF AN HYBRID ARRAY
In recent years, with the consolidation of offshore wind technology and the progress carried out for wave energy technology, the option of co-locate both technologies at the same marine area has arisen. Co-located projects are a combined solution to tackle the shared challenge of reducing technology costs or a more sustainable use of the natural resources. In particular, this paper deals with the co-location of Wave Energy Conversion (WEC) technologies into a conventional offshore wind farm. More specifically, an overtopping type of WEC technology was considered in this work to study the effects of its co-location with a conventional offshore wind park
Improving the availability of biopesticides : an interdisciplinary research project
There is a need for new, biologically-based crop protection products to serve as alternatives to or to complement synthetic chemical pesticides. An interdisciplinary research team from the natural and social sciences considered whether regulatory barriers were preventing more biopesticides reaching the market. The research coincided with a realisation by policy makers that more needed to be done to facilitate biopesticide registration, exemplified by the UK's Biopesticides Scheme. However, important differences remain between the UK and other countries such as the USA. Changes in regulatory arrangements need careful handling. The scientific work undertaken in the project provided a better understanding of the population biology of microbial control agents. Interdisciplinary work permitted a contribution to the policy debate
Forming the first planetary systems: debris around Galactic thick disc stars
The thick disc contains stars formed within the first Gyr of Galactic
history, and little is known about their planetary systems. The Spitzer MIPS
instrument was used to search 11 of the closest of these old low-metal stars
for circumstellar debris, as a signpost that bodies at least as large as
planetesimals were formed. A total of 22 thick disc stars has now been
observed, after including archival data, but dust is not found in any of the
systems. The data rule out a high incidence of debris among star systems from
early in the Galaxy's formation. However, some stars of this very old
population do host giant planets, at possibly more than the general incidence
among low-metal Sun-like stars. As the Solar System contains gas giants but
little cometary dust, the thick disc could host analogue systems that formed
many Gyr before the Sun.Comment: accepted by MNRAS Letters; 5 pages, 4 figure
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