Vertical transport and exchange of materials in the upper waters of the oceans (VERTEX): introduction to the program, hydrographic conditions and major component fluxes during VERTEX I

This paper introduces VERTEX, a multi-disciplinary research program dealing with various aspects of particle transport in the upper, high-energy layers (0-2000 m) of the ocean. Background information is presented on hydrography, biological composition of trapped particulates, and major component fluxes observed on a cruise off central California (VERTEX I). Organic C fluxes measured with two trap systems are compared with several other estimates taken from the literature. The intent of this overview paper is to provide a common setting in an economical manner, and avoid undue repetition of background and ancillary information in subsequent publications. (PDF is 43 pages).

X-ray emission from charge exchange of highly-charged ions in atoms and molecules

Charge exchange followed by radiative stabilization are the main processes responsible for the recent observations of X-ray emission from comets in their approach to the Sun. A new apparatus was constructed at JPL to measure, in collisions of HCIs with atoms and molecules, (a) absolute cross sections for single and multiple charge exchange, and (b) normalized X-ray emission cross sections. The ions are produced by the JPL HCI Facility and passed through a neutral-gas target cell. The product charge states are analyzed by a retarding potential difference technique. Results are made absolute by measuring target pressure, and incident and product ion currents. X-rays emitted from the product ions are detected with a Ge solid-state detector having a resolution of approximately 100 eV. X-ray astronomy has taken major steps forward with the recent launch of the high-resolution satellites Chandra and Newton. The cross sections reported herein are essential for the development of the solar wind comet interaction models inspired by these observations.

Air-Sea Exchange of Legacy POPs in the North Sea Based on Results of Fate and Transport, and Shelf-Sea Hydrodynamic Ocean Models

The air-sea exchange of two legacy persistent organic pollutants (POPs), γ-HCH and PCB 153, in the North Sea, is presented and discussed using results of regional fate and transport and shelf-sea hydrodynamic ocean models for the period 1996–2005. Air-sea exchange occurs through gas exchange (deposition and volatilization), wet deposition and dry deposition. Atmospheric concentrations are interpolated into the model domain from results of the EMEP MSC-East multi-compartmental model (Gusev et al, 2009). The North Sea is net depositional for γ-HCH, and is dominated by gas deposition with notable seasonal variability and a downward trend over the 10 year period. Volatilization rates of γ-HCH are generally a factor of 2–3 less than gas deposition in winter, spring and summer but greater in autumn when the North Sea is net volatilizational. A downward trend in fugacity ratios is found, since gas deposition is decreasing faster than volatilization. The North Sea is net volatilizational for PCB 153, with highest rates of volatilization to deposition found in the areas surrounding polluted British and continental river sources. Large quantities of PCB 153 entering through rivers lead to very high local rates of volatilization.

Influence of historic land use change on the biosphere-atmosphere-exchange of C and N trace gases in the humid, subtropical region of Queensland

Increases in atmospheric concentrations of the greenhouse gases (GHGs) carbon dioxide (CO2), methane (CH4), and nitrous oxide (N2O) due to human activities have been linked to climate change. GHG emissions from land use change and agriculture have been identified as significant contributors to both Australia’s and the global GHG budget. This is expected to increase over the coming decades as rates of agriculture intensification and land use change accelerate to support population growth and food production. Limited data exists on CO2, CH4 and N2O trace gas fluxes from subtropical or tropical soils and land uses. To develop effective mitigation strategies a full global warming potential (GWP) accounting methodology is required that includes emissions of the three primary greenhouse gases. Mitigation strategies that focus on one gas only can inadvertently increase emissions of another. For this reason, detailed inventories of GHGs from soils and vegetation under individual land uses are urgently required for subtropical Australia. This study aimed to quantify GHG emissions over two consecutive years from three major land uses; a well-established, unfertilized subtropical grass-legume pasture, a 30 year (lychee) orchard and a remnant subtropical Gallery rainforest, all located near Mooloolah, Queensland. GHG fluxes were measured using a combination of high resolution automated sampling, coarser spatial manual sampling and laboratory incubations. Comparison between the land uses revealed that land use change can have a substantial impact on the GWP on a landscape long after the deforestation event. The conversion of rainforest to agricultural land resulted in as much as a 17 fold increase in GWP, from 251 kg CO2 eq. ha-1 yr-1 in the rainforest to 889 kg CO2 eq. ha-1 yr-1 in the pasture to 2538 kg CO2 eq. ha-1 yr-1 in the lychee plantation. This increase resulted from altered N cycling and a reduction in the aerobic capacity of the soil in the pasture and lychee systems, enhancing denitrification and nitrification events, and reducing atmospheric CH4 uptake in the soil. High infiltration, drainage and subsequent soil aeration under the rainforest limited N2O loss, as well as promoting CH4 uptake of 11.2 g CH4-C ha-1 day-1. This was among the highest reported for rainforest systems, indicating that aerated subtropical rainforests can act as substantial sink of CH4. Interannual climatic variation resulted in significantly higher N2O emission from the pasture during 2008 (5.7 g N2O-N ha day) compared to 2007 (3.9 g N2O-N ha day), despite receiving nearly 500 mm less rainfall. Nitrous oxide emissions from the pasture were highest during the summer months and were highly episodic, related more to the magnitude and distribution of rain events rather than soil moisture alone. Mean N2O emissions from the lychee plantation increased from an average of 4.0 g N2O-N ha-1 day-1, to 19.8 g N2O-N ha-1 day-1 following a split application of N fertilizer (560 kg N ha-1, equivalent to 1 kg N tree-1). The timing of the split application was found to be critical to N2O emissions, with over twice as much lost following an application in spring (emission factor (EF): 1.79%) compared to autumn (EF: 0.91%). This was attributed to the hot and moist climatic conditions and a reduction in plant N uptake during the spring creating conditions conducive to N2O loss. These findings demonstrate that land use change in subtropical Australia can be a significant source of GHGs. Moreover, the study shows that modifying the timing of fertilizer application can be an efficient way of reducing GHG emissions from subtropical horticulture.

Effect of biochar amendment on the soil-atmosphere exchange of greenhouse gases from an intensive subtropical pasture in northern New South Wales, Australia

We assessed the effect of biochar incorporation into the soil on the soil-atmosphere exchange of the greenhouse gases (GHG) from an intensive subtropical pasture. For this, we measured N2O, CH4 and CO2 emissions with high temporal resolution from April to June 2009 in an existing factorial experiment where cattle feedlot biochar had been applied at 10 t ha-1 in November 2006. Over the whole measurement period, significant emissions of N2O and CO2 were observed, whereas a net uptake of CH4 was measured. N2O emissions were found to be highly episodic with one major emission pulse (up to 502 µg N2O-N m-2 h 1) following heavy rainfall. There was no significant difference in the net flux of GHGs from the biochar amended vs. the control plots. Our results demonstrate that intensively managed subtropical pastures on ferrosols in northern New South Wales of Australia can be a significant source of GHG. Our hypothesis that the application of biochar would lead to a reduction in emissions of GHG from soils was not supported in this field assessment. Additional studies with longer observation periods are needed to clarify the long term effect of biochar amendment on soil microbial processes and the emission of GHGs under field conditions.

Environmental factors controlling temporal and spatial variability in the soil-atmosphere exchange of CO2, CH4 and N2O from an Australian subtropical rainforest

The temporal variations in CO2, CH4 and N2O fluxes were measured over two consecutive years from February 2007 to March 2009 from a subtropical rainforest in south-eastern Queensland, Australia, using an automated sampling system. A concurrent study using an additional 30 manual chambers examined the spatial variability of emissions distributed across three nearby remnant rainforest sites with similar vegetation and climatic conditions. Interannual variation in fluxes of all gases over the 2 years was minimal, despite large discrepancies in rainfall, whereas a pronounced seasonal variation could only be observed for CO2 fluxes. High infiltration, drainage and subsequent high soil aeration under the rainforest limited N2O loss while promoting substantial CH4 uptake. The average annual N2O loss of 0.5 ± 0.1 kg N2O-N ha−1 over the 2-year measurement period was at the lower end of reported fluxes from rainforest soils. The rainforest soil functioned as a sink for atmospheric CH4 throughout the entire 2-year period, despite periods of substantial rainfall. A clear linear correlation between soil moisture and CH4 uptake was found. Rates of uptake ranged from greater than 15 g CH4-C ha−1 day−1 during extended dry periods to less than 2–5 g CH4-C ha−1 day−1 when soil water content was high. The calculated annual CH4 uptake at the site was 3.65 kg CH4-C ha−1 yr−1. This is amongst the highest reported for rainforest systems, reiterating the ability of aerated subtropical rainforests to act as substantial sinks of CH4. The spatial study showed N2O fluxes almost eight times higher, and CH4 uptake reduced by over one-third, as clay content of the rainforest soil increased from 12% to more than 23%. This demonstrates that for some rainforest ecosystems, soil texture and related water infiltration and drainage capacity constraints may play a more important role in controlling fluxes than either vegetation or seasonal variability

Integration of XML Schemas for the Exchange of FDOT Construction Project Data

An investigation of the construction data management needs of the Florida Department of Transportation (FDOT) with regard to XML standards including development of data dictionary and data mapping. The review of existing XML schemas indicated the need for development of specific XML schemas. XML schemas were developed for all FDOT construction data management processes. Additionally, data entry, approval and data retrieval applications were developed for payroll compliance reporting and pile quantity payment development.

Oxidative extraction and ion-exchange of lithium in Li2MoO3: synthesis of Li2âxMoO3 and H2MoO3

It is shown that lithium can be oxidatively extracted from Li2MoO3 at room temperature using Br2 in CHCl3. The delithiated oxides, Li2â��xMoO3 (0 < x â�¤ 1.5) retain the parent ordered rocksalt structure. Complete removal of lithium from Li2MoO3 using Br2 in CH3CN results in a poorly crystalline MoO3 that transforms to the stable structure at 280�°C. Li2MoO3 undergoes topotactic ion-exchange in aqueous H2SO4 to yield a new protonated oxide, H2MoO3.

HNbWO6 and HTaWO6: Novel oxides related to ReO3 formed by ion exchange of rutile-type LiNbWO6 and LiTaWO6

Both LiNbWO6 and LiTaWO6 undergo ion exchange in hot aqueous H2SO4 yielding the hydrates HMWO6 · H2O (M = Nb or Ta). The reaction is accompanied by a structural transformation from the rutile to the ReO3 structure. The cell constants are a = 3.783(3)Å for HNbWO6 · H2O and a = 3.785(5)Å for HTaWO6 · H2O. The ReO3 structure is retained by the dehydration products HMWO6 and MWO5.5 as well. HMWO6 phases yield H1+xMWO6 hydrogen bronzes on exposure to hydrogen in the presence of platinum catalyst.

Copy of bill of exchange of Haym Salomon and letter regarding the same

Digital image

Ion exchange of sodium chloride and sodium bicarbonate solutions using strong acid cation resins in relation to coal seam water treatment

Coal seam gas production has resulted in the production of large volumes of associated water which contains dissolved salts dominated by sodium chloride and sodium bicarbonate. Ion exchange using synthetic resins has been proposed as a method for desalination of coal seam water to make it suitable for various beneficial reuse options. This study investigated the behaviour of solutions of sodium chloride and sodium bicarbonate with respect to exchange with Lanxess S108H strong acid cation (SAC) resin. Equilibrium isotherms were created for solutions of NaCl and NaHCO3 and an actual sample of coal seam water from the Surat Basin in southern Queensland. The exchange of sodium ions arising from sodium bicarbonate was found to be considerably more favourable than exchange of sodium ions from sodium chloride solutions. This latter behaviour was attributed to the secondary decomposition of bicarbonate species under acidic conditions which resulted in the evolution of carbon dioxide and formation of water. The isotherm profiles could not be satisfactorily fitted by a single isotherm model such as the Langmuir expression. Instead, two Langmuir equations had to be simultaneously applied in order to fit the sections of the isotherm attributable to sodium ion exchange from sodium bicarbonate and sodium chloride. The shape of the isotherm profile was dependent upon the ratio of sodium chloride to sodium bicarbonate in solution and there was a high degree of correlation between simulated and actual coal seam water solutions.