The Development of a GIS-based Inventory of Standing Waters in Great Britain together with a Risk-based Prioritisation Protocol

An inventory of standing waters (freshwater lakes and lochs) wasderived from Ordnance Survey digital map data at a scale of 1:50 000 and represents the most comprehensive survey of its kind for Great Britain. The inventory includes 43 738 water bodies in England, Scotland, Wales and the Isle of Man and contains basic physical data such as location, surface area, perimeter and altitude. Catchment areas were computed for water bodies with a surface area larger than 1 ha from a digital terrain model (DTM) using customised routines in a geographical information system (GIS). The resulting polygons were then used to derive catchment-related information from a variety of national datasets including population density, livestock density, land cover, solid and drift geology, meteorological data, freshwater sensitivity status, acid deposition and conservation status. Using data derived from the inventory a risk-based prioritisation protocol was developed to identify standing waters at risk of harm from acidification and eutrophication. This information is required by the Environment Agency, Scottish Environmental Protection Agency and the U.K. statutory conservation bodies to co-ordinate actions and monitor change under international, European and national legislation.     

Collection efficiency of electrostatic precipitators by numerical simulation

A numerical simulation code has been developed to analyze the coupled electro-aerodynamic phenomena within an electrostatic precipitator operated in both the positive and negative corona modes. The space charge and current densities, as well as the static and space charge components of the electric field, are first obtained using the known cross-sections for ionization and negative ion formation. Data includes the effects of fluid flow. The above quantities (except the static field) are then corrected in a subsequent iteration for the presence of dust particles of known size distribution, charges predominantly by the field charging mechanism. The precipitator collection efficiency is calculated from the trajectories of the charged dust particles. For theory comparison, the collection efficiencies of model precipitators were measured by light-scattering techniques using oil drops as test particles. The variation of efficiency with wire-to-wire spacing will be discussed as a case study.     

A SATURATION-BASED MODEL OF RELATIVE WETNESS FOR WETLAND IDENTIFICATION1

ABSTRACT: A wetness index that was derived from Beven's distributed hillslope runoff model and based on the concept of relative wetness is introduced as a wetland identification and mapping tool. Data requirements are modified to make the model suitable for use by managers and field agents. The model predicts the relative propensity of any point or small area within a landscape unit to become saturated. This allows an index of relative wetness to be produced. Points on the landscape can then be assigned values of relative wetness. The index has potential utility for: (1) providing more detailed information on wetness conditions than binary (wetland-nonwetland) classification systems now in use; (2) assisting in wetland identification when field indicators are absent or ambiguous; (3) application in dryland environments where common wetland indicators are largely irrelevant; and (4) broad-scale wetland mapping in a geographic information systems environment using existing digital topographic and soils databases.     

Chitosan-supported palladium catalyst. IV. Influence of temperature on nitrophenol degradation and thermodynamic parameters

Glutaraldehyde cross-linked chitosan was loaded with palladium and then reduced using an in situ hydrogen generation procedure (Zn in sulfuric acid solution) to prepare a chitosan-supported palladium catalyst. This catalyst was successfully used to degrade nitrophenol in dilute solutions in the presence of sodium formate as the hydrogen donor. The influence of the initial concentration of nitrophenol and sodium formate was studied in order to determine the minimum molar ratio between these compounds required to achieve complete conversion of the nitrogenous product at two temperatures. Increasing the temperature decreased the excess of hydrogen donor required for complete conversion of nitrophenol. The temperature was also varied between 10 and 60 degrees C in order to determine the activation energy. The pseudo first-order equation was shown to fit degradation kinetics in most cases; however, for some cases it was necessary to use a variable-order equation to model the kinetics.     

Emissions study of co-firing waste carpet in a rotary kiln

Post-consumer carpet represents a high volume, high energy content waste stream. As a fuel for co-firing in cement kilns, waste carpet, like waste tires, has potential advantages. Technological challenges to be addressed include assessing potential emissions, in particular NO emissions (from nylon fiber carpets), and optimizing the carpet feed system. This paper addresses the former. Results of pilot-scale rotary kiln experiments demonstrate the potential for using post-consumer waste carpet as a fuel in cement kilns. Continuous feeding of shredded carpet fiber and ground carpet backing, at rates of up to 30% of total energy input, resulted in combustion without transient puffs and with almost no increase in CO and other products of incomplete combustion as compared to kiln firing natural gas only. NO emissions increased with carpet waste co-firing due to the nitrogen content of nylon fiber. In these experiments with shredded fiber and finely ground backing, carpet nitrogen conversion to NO ranged from 3 to 8%. Conversion increased with enhanced mixing of the carpet material and air during combustion. Carpet preparation and feeding method are controlling factors in fuel N conversion.     

Biosynthesis of cyanogenic glycosides

Cyanogenic glycosides are secondary plant compounds that occur widely in the plant kingdom. They are the source of HCN which can render the plant toxic if it is taken as food. The enzymes responsible for production of the HCN have long been known. More recent biosynthetic studies have established certain protein amino acids as precursors of the aglycones, and indicate N-hydroxyamino acids, aldoximes, nitriles and α-hydroxynitriles as intermediates. In sorghum the several biosynthetic enzymes catalyzing the flow of carbon atoms from l-tyrosine through such nitrogenous intermediates are located in a membrane fraction and may be capable of metabolic channeling.     

Laboratory growth of early juveniles of the western rock lobster Panulirus longipes cygnus

Growth in the laboratory of early juvenile Panulirus longipes cygnus George from the last larval (puerulus) stage to approximately 3 years of age is described. Specimens were held either in isolation or in groups of 3 or 5 rock lobsters per tank, at constant temperatures of 20° or 23°C (both ± 0.5 C°) or at the temperatures of the incoming seawater, which ranged annually between 14.9° and 25.9°C. Metamorphosis from the planktonic puerulus to the settled juvenile existence involved a reduction in size and usually took about two moults to complete. By this time the sexes could be distinguished. Growth in aquaria from the 2nd moult after puerulus until the juveniles were approximately 3 years of age was adequately described by exponential (von Bertalanffy) functions, with the growth curves gradually tapering off after the rock lobsters had reached 40 to 42 mm carapace length. Young juveniles were not gregarious until 20 to 25 mm carapace length (approximately 1.5 years old), however, growth rates were not depressed in individuals held in isolation up to approximately 3 years of age. Temperature markedly affected growth; the fastest observed growth up to 450 days was at 23°C. Variations in temperature resulted in decreased growth rates in winter and the reverse in summer in individuals at ambient temperatures. There was an increase in the moult increment at successive moults corresponding to increased carapace length, but increased growth rates were achieved through shortening the intermoult duration. The period of development from the puerulus stage until approximately 1.5 years of age is a distinct phase of development both of behaviour and growth.     

Spatial and time variations of radon-222 concentration in the atmosphere of a dead-end horizontal tunnel

The concentration of radon-222 has been monitored since 1995 in the atmosphere of a 2 m transverse dimension, 128 m long, dead-end horizontal tunnel located in the French Alps, at an altitude of 1600 m. Most of the time, the radon concentration is stable, with an average value ranging from 200 Bq m(-3) near the entrance to about 1000 Bq m(-3) in the most confined section, with an equilibrium factor between radon and its short-lived decay products varying from 0.61 to 0.78. However, radon bursts are repeatedly observed, with amplitudes reaching up to 36 x 10(3) Bq m(-3) and durations varying from one to several weeks, with similar spatial variations along the tunnel as the background concentration. These spatial variations are qualitatively interpreted in terms of natural ventilation. Comparing the radon background concentration with the measured radon exhalation flux at the wall yields an estimate of 8+/-2 x 10(-6) s(-1) (0.03+/-0.007 h(-1)) for the ventilation rate. The hypothesis that the bursts could be due to transient changes in ventilation can be ruled out. Thus, the bursts are the results of transient increased radon exhalation at the walls, that could be due to meteorological effects or possibly combined hydrological and mechanical forcing associated with the water level variations of the nearby Roselend reservoir lake. Such studies are of interest for radiation protection in poorly ventilated underground settings, and, ultimately, for a better understanding of radon exhalation associated with tectonic or volcanic processes.     

The effect of phosphogypsum on greenhouse gas emissions during cattle manure composting

Phosphogypsum (PG), a by-product of the phosphate fertilizer industry, reduces N losses when added to composting livestock manure, but its impact on greenhouse gas emissions is unclear. The objective of this research was to assess the effects of PG addition on greenhouse gas emissions during cattle feedlot manure composting. Sand was used as a filler material for comparison. The seven treatments were PG10, PG20, PG30, S10, S20, and S30, representing the rate of PG or sand addition at 10, 20, or 30% of manure dry weight and a check treatment (no PG or sand) with three replications. The manure treatments were composted in open windrows and turned five times during a 134-d period. Addition of PG significantly increased electrical conductivity (EC) and decreased pH in the final compost. Total carbon (TC), total nitrogen (TN), and mineral nitrogen contents in the final composted product were not affected by the addition of PG or sand. From 40 to 54% of initial TC was lost during composting, mostly as CO(2), with CH(4) accounting for <14%. The addition of PG significantly reduced CH(4) emissions, which decreased exponentially with the compost total sulfur (TS) content. The emission of N(2)O accounted for <0.2% of initial TN in the manure, increasing as compost pH decreased from alkaline to near neutral. Based on the total greenhouse gas budget, PG addition reduced greenhouse gas emissions (CO(2)-C equivalent) during composting of livestock manure by at least 58%, primarily due to reduced CH(4) emission.