Hydrogen and oxygen on a /110/ nickel surface

Hydrogen-oxygen reaction on nickel surface, electron diffraction stud

Historical changes (1905-2005) in external phosphorus loads to Loch Leven, Scotland, UK

This article reviews historical changes in the total phosphorus (TP) inputs to Loch Leven, Scotland, UK. Data derived from palaeolimnological records suggest that inputs in the early 1900s were about 6 t TP year-1 (0.45 g TP m-2 year-1). By 1985, this had risen to about 20 t TP year-1 (1.5 g TP m-2 year-1) due to increases in runoff from agricultural land and discharges from point sources. By the late 1970s, increased TP inputs were causing serious degradation of lake water quality. Most noticeably, there had been an increase in cyanobacterial blooms. A catchment management plan was implemented in the early 1990s. This resulted in a 60% reduction in the annual TP input between 1985 (20 t TP year-1/1.5 g TP m-2 year-1) and 1995 (8 t TP year-1/0.6 g TP m-2 year-1). The main reduction was associated with better control of point source discharges, but attempts were also made to reduce inputs from diffuse sources. The reduction in external TP loading to the lake led to a marked decline in TP retention by the lake each year

A review of the effectiveness of different on-site wastewater treatment systems and their management to reduce phosphorus pollution

Diffuse water pollution (DWP) is a major cause of SSSI waterbodies not meeting favourable condition and/or water quality objectives set under the EC Water Framework and Habitats Directives. Diffuse water pollution can come from a variety of sources, including agriculture, small un-consented point source discharges, and runoff from roads or urban areas. Natural England estimates that around 166 SSSIs are affected by DWP where pollution reduction plans are being developed for all or part of these sites; 40 of these plans cover Natura 2000 Protected Areas. Many of these DWP plans highlight small domestic discharges (SDDs), as potential sources of nutrients that are causing water quality problems, although often it is not known how significant they are. These include those from septic tanks (STs) and package treatment plants (PTPs). The most frequently highlighted problem associated with discharges from these systems is phosphorus (P) pollution, which causes eutrophication problems. However, it is often unclear how such problems should be resolved because there is little information on the efficacy of management advice that is currently being given to householders. Such advice includes the regular de-sludging of tanks, the use of P-free detergents, and the replacement of traditional STs with PTPs. This review assessed the information contained in publicly available literature with a view to enabling Natural England to improve the advice that they give on the correct management of SSDs in relation to reducing their P-related impacts on designated sites. The review found that there was very little knowledge and information available that could be used to develop a more evidence based approach to reducing P discharges from these systems. Based on the existing knowledge and information reviewed, it was concluded that the most effective options for reducing the levels of P discharged from on-site sewage treatment tanks to the environment are as follows: 1) Reducing P inputs to the tank, e.g. through the use of P free detergents, and 2) Using chemical precipitation to retain P within the tank and incorporate it into the sludge. It should be noted that the use of P free detergents is becoming increasingly common due to the introduction of recent European legislation (European Union, 2012). It is also important to note that, whilst chemical precipitation is an effective method of retaining P within tanks, issues of personal and environmental safety can be associated with this approach, and at this stage it is not appropriate for widespread use. In addition to the above, many other approaches to tank management also have the potential to effectively reduce P discharges from these systems. However, at present, there is insufficient data and information available for their level of efficacy to be determined. Other options that are often recommended include frequent de-sludging or replacing traditional STs with PTPs. It is unclear how and to what extent these other options are effective at reducing the P concentration in tank effluent or whether, in practice, these approaches could be making the situation even worse in some situations. In areas where the water table is high, ie <1.5 m below soil surface, impacts on nearby watercourses can probably be reduced by installing mounded soakaway systems. This review also identified key gaps in knowledge and recommends that further research be undertaken to answer the following questions: 1) To what extent do P concentrations of ST effluents differ from those of PTPs? 2) How does temporal variation in P output from STs and PTPs (from sub-daily to seasonal) affect the level of uncertainty associated with collecting and analysing a single effluent sample for monitoring/regulatory purposes? 3) How effective are STs and PTPs at breaking down waste if usage is intermittent or seasonal and what are the implications for levels of P in the discharged effluent? 4) Does de-sludging reduce effluent P concentrations? The results of this research would provide information on the key factors that affect effluent P concentrations from these tanks. This could then be incorporated into advice give to householders on how to reduce P outputs from these systems

Ammonia adsorption and decomposition on a tungsten /211/ surface

Ammonia adsorption and decomposition on tungsten 211 surface studied by mass spectrometry, electron diffraction, and changes in work functio

First steps in the oxidation of a /110/ nickel surface

Initial steps in oxidation of nickel surface studied using low energy back-reflection electron diffractio

Method of cross-linking polyvinyl alcohol and other water soluble resins

A self supporting sheet structure comprising a water soluble, noncrosslinked polymer such as polyvinyl alcohol which is capable of being crosslinked by reaction with hydrogen atom radicals and hydroxyl molecule radicals is contacted with an aqueous solution having a pH of less than 8 and containing a dissolved salt in an amount sufficient to prevent substantial dissolution of the noncrosslinked polymer in the aqueous solution. The aqueous solution is then irradiated with ionizing radiation to form hydrogen atom radicals and hydroxyl molecule radicals and the irradiation is continued for a time sufficient to effect crosslinking of the water soluble polymer to produce a water insoluble polymer sheet structure. The method has particular application in the production of battery separators and electrode envelopes for alkaline batteries

Segregation by thermal diffusion in granular shear flows

Segregation by thermal diffusion of an intruder immersed in a sheared granular gas is analyzed from the (inelastic) Boltzmann equation. Segregation is induced by the presence of a temperature gradient orthogonal to the shear flow plane and parallel to gravity. We show that, like in analogous systems without shear, the segregation criterion yields a transition between upwards segregation and downwards segregation. The form of the phase diagrams is illustrated in detail showing that they depend sensitively on the value of gravity relative to the thermal gradient. Two specific situations are considered: i) absence of gravity, and ii) homogeneous temperature. We find that both mechanisms (upwards and downwards segregation) are stronger and more clearly separated when compared with segregation criteria in systems without shear.Comment: 8 figures. To appear in J. Stat. Mec

Utilizing remote sensing of thematic mapper data to improve our understanding of estuarine processes and their influence on the productivity of estuarine-dependent fisheries

The land-water interface of coastal marshes may influence the production of estuarine-dependent fisheries more than the area of these marshes. To test this hypothesis, a spatial model was created to explore the dynamic relationship between marshland-water interface and level of disintegration in the decaying coastal marshes of Louisiana's Barataria, Terrebonne, and Timbalier basins. Calibrating the model with Landsat Thematic Mapper satellite imagery, a parabolic relationship was found between land-water interface and marsh disintegration. Aggregated simulation data suggest that interface in the study area will soon reach its maximum and then decline. A statistically significant positive linear relationship was found between brown shrimp catch and total interface length over the past 28 years. This relationship suggests that shrimp yields will decline when interface declines, possibly beginning about 1995

Utilizing remote sensing of Thematic Mapper data to improve our understanding of estuarine processes and their influence on the productivity of estuarine-dependent fisheries

The purpose of the project is to refine and validate a probabilistic spatial computer model through the analyses of thematic mapper imagery. The model is designed to determine how the interface between marshland and water changes as marshland is converted to water in a disintegrating marsh. Coastal marshland in Louisiana is disintegrating at the rate of approximately 40 sq mi a year, and an evaluation of the potential impact of this loss on the landings of estuarine-dependent fisheries is needed by fisheries managers. Understanding how marshland-water interface changes as coastal marshland is lost is essential to the process of evaluating fisheries effects, because several studies suggest that the production of estuarine-dependent fish and shellfish may be more closely related to the interface between marshland and water than to acreage of marshland. The need to address this practical problem has provided an opportunity to apply some scientifically interesting new techniques to the analyses of satellite imagery. Progress with the development of these techniques is the subject of this report

Utilizing remote sensing of Thematic Mapper data to improve our understanding of estuarine processes and their influence on the productivity of estuarine-dependent fisheries

LANDSAT thematic mapper (TM) data are being used to refine and validate a stochastic spatial computer model to be applied to coastal resource management problems in Louisiana. Two major aspects of the research are: (1) the measurement of area of land (or emergent vegetation) and water and the length of the interface between land and water in TM imagery of selected coastal wetlands (sample marshes); and (2) the comparison of spatial patterns of land and water in the sample marshes of the imagery to that in marshes simulated by a computer model. In addition to activities in these two areas, the potential use of a published autocorrelation statistic is analyzed