Air pollution modelling for environmental impact assessment

The aims of the lectures are: (i) to explain what concentration fluctuations are; (ii) to illustrate their importance in environmental impact assessment; (iii) to discuss some factors relevant to the quantitative description of concentration fluctuations; (iv) to describe a framework for this description. It will be clear from the lectures, and from others later in the Workshop that there is rapidly increasing awareness of the importance of concentration fluctuations and, consequently, much research activity into their properties. Not surprisingly there are still many unsolved problems, and a by-product of the lectures will be to highlight one or two of the most important

Some remarks on modelling the PDF of the concentration of a dispersing scalar in turbulence

The paper deals with the probability density function (PDF) of the concentration of a scalar within a turbulent flow. Following some comments about the overall structure of the PDF, and its approach to a limit at large times, attention focusses on the so-called small scale mixing term in the evolution equation for the PDF. This represents the effect of molecular diffusion in reducing concentration uctuations, eventually to zero. Arguments are presented which suggest that this quantity could, in certain circumstances, depend inversely upon the PDF, and a particular example of this leads to a new closure hypothesis. Consequences of this, especially similarity solutions, are explored for the case when the concentration field is statistically homogeneous

Concentration fluctuations in atmospheric dispersion

This report summarizes work done at Brunel University under Agreement No.2066/62 from 15 July 1986 to 14 July 1989. The title of the project was Concentration Fluctuations in Atmospheric Dispersion. The report has three principal components. These are: (i) theoretical work on the electrostatic effects associated with dispersing charged tracers. (ii) extensive analysis of several datasets taken with the CDE sensor system, particularly one obtained at RAF Cardington on 10 May 1988; (iii) interpretation of the results of the analysis. The conclusions of the report include recommendations for further work to exploit the advantages that the system has over many others

Molecular genetic analysis of chemical-induced sporulation of Myxococcus xanthus

Mutants resistant to glycerol-induction of sporulation were isolated from wild-type M. xanthus. The glycerol-resistant qlrA and alrB loci, previously mapped by Mx.8 transductions, were analysed by restriction mapping of clones and by complementation analysis. The location of the qlrA gene(s) was mapped to within a 2.2kb region, whilst the qlrB region proved very complex. The qlrA and qlrB gene products were reguired early in chemical-induced sporulation since two chemical-inducible lacZ fusions were not expressed in either qlrA or qlrB mutants during chemical-induction. Only a minority of the glycerol-resistant mutants were unable to undergo fruiting body sporulation. Complementation studies of the qlrA and qlrB regions confirmed that mutations in chemical-induced and fruiting body sporulation were not linked. This suggests that the induction pathways of chemical-induced sporulation and fruiting body sporulation share few common genes. Glycerol-resistant mutants were isolated from a non- motile strain, which is unable to form fruiting bodies. The majority of these mutants were able to form spores in the absence of fruiting bodies. Two mutants were unable to form spores. Isolating such mutants may provide a means of identifying truly sporulation-deficient mutants. Expression from the chemical-inducible isqB>lacZ fusion, identified previously in a promoter probe vector, was blocked in 24 different glycerol-resistant mutants. Hence, the gene product was reguired late in the chemical-induced sporulation pathway. The complete transcription unit was cloned and disruption of the region by the insertion of a tetracycline cassette demonstrated that the gene is not essential for chemical- induced or starvation-induced sporulation. Expression from a second chemical-inducible lacZ fusion, ÎÎDK4530, identified previously by random Tn£ lac insertion, was suppressed by amino acids in the growth media during chemical-induced sporulation and was blocked in both qlrA and qlrB mutants. Hence, expression of the gene product is dependent on both the qlrA+ and qlrB+ genes

Enhancing public safety and security of critical national infrastructure utilizing the Nigerian Satellite Augmentation System (NSAS)

After the First World War, radio time signals offered alternative technology for determination of the Greenwich time and thus longitude at sea. The first manifestation of new technology capable of usurping the super accurate mechanical chronometers occurred in 1904, when the United States Navy began to experiment with the transmission of radio-time signals as an aid to the determination of longitude (Davies, 1978; Lawal & Chatwin, 2011). The challenge in precision continued with precision in Navigation systems, which depends on electromagnetic waves travelling at 300,000,000 m/s, which means that one microsecond error in a vessel’s time will result in 300metres of navigational error. The Global Positioning System (GPS) originated from the Navigation System with Timing and Ranging known as NAVSTAR, which was initiated by the Joint Program Office (JPO) of the U.S. Department of Defence (DoD) in 1973.The first GPS satellite was sent into orbit in 1978. Initial Operational Capability (IOC) was reached in July 1993 with 24 satellites, while Full Operational Capability (FOC) was declared on July, 17th, 1995. Improvement in accuracy for general transportation, especially in aviation, ushered in augmentation systems. The quest for performance focused on the ability to accurately transmit and keep time signals stable up to the picosecond level and even more in receivers and clock reference signals for space systems, especially in navigation satellites using high performance oscillators ranging from ultra-stable quartz crystals with ovenized control to high performance atomic circuits (Lawal & Chatwin, 2011). The Satellite-Based Augmentation System (SBAS) arose from the need to provide continuity, availability, integrity and accuracy of global positioning signals to eliminate errors and compensate for discrepancies associated with GPS signals and other navigation systems. The NigComSat-1R Navigation (L-band) payload is a Space Based Augmentation System meant to provide a Navigation Overlay Service (NOS) similar to the European Geostationary Navigation Overlay Service (EGNOS). This paper describes the huge untapped potential that the hybrid satellite offers in the area of public safety, security of critical national infrastructure, aviation, maritime, defense, effectiveness of Location Based Services for Emergency and Crisis management amongst other applications; it thus fills a great gap in the augmentation systems for Africa

Monte Carlo simulation of electron and proton irradiation of carbon nanotube and graphene transistors

Carbon-based nanotechnology electronics can provide high performance, low-power and low-weight solutions, which are very suitable for innovative aerospace applications. However, its application in the space environment where there is a radiation hazard, requires an assessment of the response of such electronic products to the background irradiance. To explore the potential of carbon-based nanotechnology, Monte Carlo simulations of radiation interacting with a gate-all-around carbon nanotube (GAACNFET) and a top-gated graphene FET are presented. Geant4 is used to calculate the energy deposited into the dielectric layers and the displacement damage in the nanosemiconductors under proton and electron irradiation. Both an unshielded and two cases with 250 μm thick NiFe and Pb shielding are tested at a fluence of 1015 m-2. The energy range of the particles considered is 10-2 – 102 MeV for the unshielded and 1 – 103 MeV for the shielded case. The results indicate that the graphene transistor is more susceptible to displacement damage than the CNT-based syste

A comparison of two regularization methods based on the Sussex EIM MK4 system

A comparison of two regularization methods: the general regularization method and the Sheffield method using the voltage ratio rather than the difference

Geographical catch distribution of yellowfin and skipjack tuna in the Eastern Pacific Ocean, 1967-1970, and fleet and total catch statistics, 1962-1970

ENGLISH: Logbook records of tuna vessels fishing in the eastern Pacific Ocean were used to prepare charts showing the distribution of yellowfin tuna and skipjack catches by i-degree area, by quarter of the year, and by gear, for the years 1967-1970. Recent changes in the geographical distribution of yellowfin catch are illustrated. Also given are annual catch statistics and the composition of the international tuna fishing fleets which operated in the Commission's Yellowfin Regulatory Area each year, 1962-1970. SPANISH: Los registros de los cuadernos de bitácora de los barcos pesqueros de atún en el Océano Pacífico oriental se usaron para preparar gráficos que presentan para los años de 1967-1970, la distribución de captura del atún aleta amarilla y barrilete por área de 1 grado, trimestre del año y, por las artes. Se ilustran los recientes cambios en la distribución geográfica de la captura del atún aleta amarilla. Se presentan también las estadísticas de captura anual y la composición de la flota internacional de pesca, que explota cada año el Area Reglamentaria de la Comisión, 1962-1970. (PDF contains 95 pages.