Science.gov

Sample records for primary aluminum production

  1. Diffuse parenchymal diseases associated with aluminum use and primary aluminum production.

    PubMed

    Taiwo, Oyebode A

    2014-05-01

    Aluminum use and primary aluminum production results in the generation of various particles, fumes, gases, and airborne materials with the potential for inducing a wide range of lung pathology. Nevertheless, the presence of diffuse parenchymal or interstitial lung disease related to these processes remains controversial. The relatively uncommon occurrence of interstitial lung diseases in aluminum-exposed workers--despite the extensive industrial use of aluminum--the potential for concurrent exposure to other fibrogenic fibers, and the previous use of inhaled aluminum powder for the prevention of silicosis without apparent adverse respiratory effects are some of the reasons for this continuing controversy. Specific aluminum-induced parenchymal diseases described in the literature, including existing evidence of interstitial lung diseases, associated with primary aluminum production are reviewed.

  2. Risk of ischemic heart disease among primary aluminum production workers

    SciTech Connect

    Theriault, G.P.; Tremblay, C.G.; Armstrong, B.G.

    1988-01-01

    The risk of ischemic heart disease (IHD) has been studied in relation to working conditions encountered in a primary aluminum smelter employing over 6,000 men. During the period 1975-1983, 306 new cases of IHD were identified which were matched with 575 referents. A logistic regression analysis was performed to adjust for differences in smoking habits, high blood pressure, hyperglycemia, hypercholesterolemia, and obesity. Results from this showed that white collar workers had a significantly lower risk of IHD (odds ratio 0.47, 95% confidence interval 0.31-0.70). Among blue collar workers, a significantly higher risk was observed for workers in the reduction division of the plant (OR 1.72, CI 1.09-2.97) including, in particular, Soderberg (OR 1.71, CI 1.07-2.72) and prebake (OR 2.26, CI. 1.27-4.02) potroom workers. The risk of IHD did not increase with the length of time worked in these occupations. The search for associations (among blue collar workers) of risk with nine specific contaminants (benzene soluble material, fluoride, total dust, sulfur dioxide, carbon monoxide, thermal stress, noise, physical load, and mental load) proved inconclusive, with no association reaching statistical significance.

  3. Final Technical Report Microwave Assisted Electrolyte Cell for Primary Aluminum Production

    SciTech Connect

    Xiaodi Huang; J.Y. Hwang

    2007-04-18

    This research addresses the high priority research need for developing inert anode and wetted cathode technology, as defined in the Aluminum Industry Technology Roadmap and Inert Anode Roadmap, with the performance targets: a) significantly reducing the energy intensity of aluminum production, b) ultimately eliminating anode-related CO2 emissions, and c) reducing aluminum production costs. This research intended to develop a new electrometallurgical extraction technology by introducing microwave irradiation into the current electrolytic cells for primary aluminum production. This technology aimed at accelerating the alumina electrolysis reduction rate and lowering the aluminum production temperature, coupled with the uses of nickel based superalloy inert anode, nickel based superalloy wetted cathode, and modified salt electrolyte. Michigan Technological University, collaborating with Cober Electronic and Century Aluminum, conducted bench-scale research for evaluation of this technology. This research included three sub-topics: a) fluoride microwave absorption; b) microwave assisted electrolytic cell design and fabrication; and c) aluminum electrowinning tests using the microwave assisted electrolytic cell. This research concludes that the typically used fluoride compound for aluminum electrowinning is not a good microwave absorbing material at room temperature. However, it becomes an excellent microwave absorbing material above 550°C. The electrowinning tests did not show benefit to introduce microwave irradiation into the electrolytic cell. The experiments revealed that the nickel-based superalloy is not suitable for use as a cathode material; although it wets with molten aluminum, it causes severe reaction with molten aluminum. In the anode experiments, the chosen superalloy did not meet corrosion resistance requirements. A nicked based alloy without iron content could be further investigated.

  4. Primary Aluminum Plants Worldwide - 1998

    USGS Publications Warehouse

    1999-01-01

    The 1990 U.S. Bureau of Mines publication, Primary Aluminum Plants Worldwide, has been updated and is now available. The 1998 USGS edition of Primary Aluminum Plants Worldwide is published in two parts. Part I—Detail contains information on individual primary smelter capacity, location, ownership, sources of energy, and other miscellaneous information. Part II—Summary summarizes the capacity data by country

  5. 40 CFR 421.20 - Applicability: description of the primary aluminum smelting subcategory.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... primary aluminum smelting subcategory. 421.20 Section 421.20 Protection of Environment ENVIRONMENTAL... CATEGORY Primary Aluminum Smelting Subcategory § 421.20 Applicability: description of the primary aluminum... production of aluminum from alumina in the Hall-Heroult process....

  6. 40 CFR 421.20 - Applicability: description of the primary aluminum smelting subcategory.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... primary aluminum smelting subcategory. 421.20 Section 421.20 Protection of Environment ENVIRONMENTAL... CATEGORY Primary Aluminum Smelting Subcategory § 421.20 Applicability: description of the primary aluminum... production of aluminum from alumina in the Hall-Heroult process....

  7. 40 CFR 421.20 - Applicability: description of the primary aluminum smelting subcategory.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... primary aluminum smelting subcategory. 421.20 Section 421.20 Protection of Environment ENVIRONMENTAL... CATEGORY Primary Aluminum Smelting Subcategory § 421.20 Applicability: description of the primary aluminum... production of aluminum from alumina in the Hall-Heroult process....

  8. 40 CFR 421.20 - Applicability: description of the primary aluminum smelting subcategory.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... primary aluminum smelting subcategory. 421.20 Section 421.20 Protection of Environment ENVIRONMENTAL... CATEGORY Primary Aluminum Smelting Subcategory § 421.20 Applicability: description of the primary aluminum... production of aluminum from alumina in the Hall-Heroult process....

  9. 40 CFR 421.20 - Applicability: description of the primary aluminum smelting subcategory.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... primary aluminum smelting subcategory. 421.20 Section 421.20 Protection of Environment ENVIRONMENTAL... CATEGORY Primary Aluminum Smelting Subcategory § 421.20 Applicability: description of the primary aluminum... production of aluminum from alumina in the Hall-Heroult process....

  10. RECOVERY OF ALUMINUM FROM FISSION PRODUCTS

    DOEpatents

    Blanco, R.E.; Higgins, I.R.

    1962-11-20

    A method is given for recovertng aluminum values from aqueous solutions containing said values together with fission products. A mixture of Fe/sub 2/O/ sub 3/ and MnO/sub 2/ is added to a solution containing aluminum and fission products. The resulting aluminum-containing supernatant is then separated from the fission product-bearing metal oxide precipitate and is contacted with a cation exchange resin. The aluminum sorbed on the resin is then eluted and recovered. (AEC)

  11. Production of aluminum metal by electrolysis of aluminum sulfide

    DOEpatents

    Minh, Nguyen Q.; Loutfy, Raouf O.; Yao, Neng-Ping

    1984-01-01

    Production of metallic aluminum by the electrolysis of Al.sub.2 S.sub.3 at 700.degree.-800.degree. C. in a chloride melt composed of one or more alkali metal chlorides, and one or more alkaline earth metal chlorides and/or aluminum chloride to provide improved operating characteristics of the process.

  12. Community Health Risk Assessment of Primary Aluminum Smelter Emissions

    PubMed Central

    Larivière, Claude

    2014-01-01

    Objective: Primary aluminum production is an industrial process with high potential health risk for workers. We consider in this article how to assess community health risks associated with primary aluminum smelter emissions. Methods: We reviewed the literature on health effects, community exposure data, and dose–response relationships of the principal hazardous agents emitted. Results: On the basis of representative measured community exposure levels, we were able to make rough estimates on health risks associated with specific agents and categorize these as none, low, medium, or high. Conclusions: It is possible to undertake a rough-estimate community Health Risk Assessment for individual smelters on the basis of information available in the epidemiological literature and local community exposure data. PMID:24806724

  13. Numerical simulation of the aluminum production

    NASA Astrophysics Data System (ADS)

    Popov, P. A.; Vabishchevich, P. N.

    2014-11-01

    Discusses the peculiarities of scientific and technical research problems based on mathematical modeling and computational experiment. Modern computer technology used in the modernization and development of new technologies of aluminum production. Marked features of mathematical models and software applications of multiphysics modeling of the aluminum electrolyzer.

  14. Commonwealth Aluminum: Manufacturer Conducts Plant-Wide Energy Assessments at Two Aluminum Sheet Production Operations;

    SciTech Connect

    Not Available

    2006-04-01

    DOE Industrial Technologies Program case study describes the savings possible if Commonwealth Aluminum (now Aleris Rolled Products) makes improvements noted in energy assessments at two aluminum mills.

  15. Commonwealth Aluminum: Manufacturer Conducts Plant-Wide Energy Assessments at Two Aluminum Sheet Production Operations

    SciTech Connect

    2006-04-01

    DOE Industrial Technologies Program case study describes the savings possible if Commonwealth Aluminum (now Aleris Rolled Products) makes improvements noted in energy assessments at two aluminum mills.

  16. 75 FR 70689 - Kaiser Aluminum Fabricated Products, LLC; Kaiser Aluminum-Greenwood Forge Division; Currently...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-11-18

    ... in the Federal Register on November 17, 2009 (74 FR 59254). At the request of the State agency and a... Employment and Training Administration Kaiser Aluminum Fabricated Products, LLC; Kaiser Aluminum- Greenwood... Aluminum Fabricated Products, LLC, Kaiser Aluminum-Greenwood Forge Division, including on- site...

  17. Carbothermic Aluminum Production Using Scrap Aluminum As A Coolant

    DOEpatents

    LaCamera, Alfred F.

    2002-11-05

    A process for producing aluminum metal by carbothermic reduction of alumina ore. Alumina ore is heated in the presence of carbon at an elevated temperature to produce an aluminum metal body contaminated with about 10-30% by wt. aluminum carbide. Aluminum metal or aluminum alloy scrap then is added to bring the temperature to about 900-1000.degree. C. and precipitate out aluminum carbide. The precipitated aluminum carbide is filtered, decanted, or fluxed with salt to form a molten body having reduced aluminum carbide content.

  18. Electricity in the production of metals: From aluminum to zinc

    NASA Astrophysics Data System (ADS)

    Evans, J. W.

    1995-04-01

    This article treats some electrometallurgical and electromagnetic aspects of the production of metals, but it opens with an examination of whether there is ldelectricity” (i.e., vitality) in the primary metals industries, particularly within the United States of America. That question is examined in terms of the economics of two examples: aluminum and zinc. Then, three examples are provided of potential improvements in the production of metals arising from industrial and university research: use of new electrode materials in Hall-Héroult cells to reduce energy consumption in aluminum smelting, the fluidized bed electrowinning of copper and other metals, and the employment of electromagnetic forces in metals processing, particularly electromagnetic casting. The article concludes with observations on the paucity of United States support for research and development (R & D) in primary metals production, compared with that of other industrial activities and of other nations, and suggests a prognosis for the future of academic research and teaching in extractive and process metallurgy.

  19. Electricity in the production of metals: From aluminum to zinc

    SciTech Connect

    Evans, J.W.

    1995-04-01

    This article treats some electrometallurgical and electromagnetic metals. but it opens with an examination of whether there is ``electricity`` (i.e., vitality) in the primary metals industries, particularly within the United States of America. That question is examined in terms of the economics of two examples: aluminum and zinc. Then, three examples are provided of potential improvements in the production of metals arising front industrial and university research: use of new electrode materials in Hall-Heroult cells to reduce energy consumption in aluminum smelting, the fluidized bed electrowinning of copper and other metals, and the employment of electromagnetic forces in metals processing, particularly electromagnetic casting. The article concludes with observations on the paucity of United States support for research and development (R and D) in primary metals production, compared with that of the industrial activities and of other nations. and suggests a prognosis for the future of arcade research and teaching in extractive and process metallurgy.

  20. Production of aluminum metal by electrolysis of aluminum sulfide

    DOEpatents

    Minh, N.Q.; Loutfy, R.O.; Yao, N.P.

    1982-04-01

    Metallic aluminum may be produced by the electrolysis of Al/sub 2/S/sub 3/ at 700 to 800/sup 0/C in a chloride melt composed of one or more alkali metal chlorides, and one or more alkaline earth metal chlorides and/or aluminum chloride to provide improved operating characteristics of the process.

  1. Updated Life-Cycle Assessment of Aluminum Production and Semi-fabrication for the GREET Model

    SciTech Connect

    Dai, Qiang; Kelly, Jarod C.; Burnham, Andrew; Elgowainy, Amgad

    2015-09-01

    This report serves as an update for the life-cycle analysis (LCA) of aluminum production based on the most recent data representing the state-of-the-art of the industry in North America. The 2013 Aluminum Association (AA) LCA report on the environmental footprint of semifinished aluminum products in North America provides the basis for the update (The Aluminum Association, 2013). The scope of this study covers primary aluminum production, secondary aluminum production, as well as aluminum semi-fabrication processes including hot rolling, cold rolling, extrusion and shape casting. This report focuses on energy consumptions, material inputs and criteria air pollutant emissions for each process from the cradle-to-gate of aluminum, which starts from bauxite extraction, and ends with manufacturing of semi-fabricated aluminum products. The life-cycle inventory (LCI) tables compiled are to be incorporated into the vehicle cycle model of Argonne National Laboratory’s Greenhouse Gases, Regulated Emissions, and Energy Use in Transportation (GREET) Model for the release of its 2015 version.

  2. Conceptual Design for Lower-Energy Primary Aluminum

    NASA Astrophysics Data System (ADS)

    Warner, N. A.

    2008-04-01

    Operating parameters have been identified such that slag melts typical of other carbothermic aluminum processes are thermodynamically unstable. This facilitates the direct reaction of carbon in carbon-saturated aluminum with alumina under dispersed-contact high-intensity conditions. A conceptual design for one million tonnes per annum (1 Mtpa) aluminum production from Bayer alumina is developed. Freestanding graphite reactors and an ancillary plant encapsulated by inert gas are totally unconstrained within refractory-lined shells. Electrical conductive heating and melt circulation in closed loops, employing a 10 vol pct dispersion of fine carbon particles in aluminum (slurry), transports sensible heat to a single pressurized metal-producing reactor (MPR) to satisfy the endothermicity. In the proposed plant, an MPR at 0.28 MPa (2.8 bar) and 2433 K (2160 °C) with a hearth 2-m-wide × 190-m-long leads the melt via a barometric leg back to essentially atmospheric pressure, for further in-line processing. The impeller-stirred assimilation of fine carbon particles is followed by multistage gas-lift pumping to provide a 5.4-m total head, as required by two parallel straight-line melt-conductive heaters 1 m in diameter × 226 m in length. Overall energy-consumption figures 28.7 pct lower than today’s more recently installed Hall Heroult electrolytic plants are predicted, with 51.3 pct less purchased electricity, supplemented with 1.10 times the stoichiometric elemental carbon.

  3. Aluminum in Pediatric Parenteral Nutrition Products: Measured Versus Labeled Content

    PubMed Central

    Poole, Robert L.; Pieroni, Kevin P.; Gaskari, Shabnam; Dixon, Tessa K.; Park, KT; Kerner, John A.

    2011-01-01

    OBJECTIVE Aluminum is a contaminant in all parenteral nutrition solutions. Manufacturers currently label these products with the maximum aluminum content at the time of expiry, but there are no published data to establish the actual measured concentration of aluminum in parenteral nutrition solution products prior to being compounded in the clinical setting. This investigation assessed quantitative aluminum content of products commonly used in the formulation of parenteral nutrition solutions. The objective of this study is to determine the best products to be used when compounding parenteral nutrition solutions (i.e., those with the least amount of aluminum contamination). METHODS All products available in the United States from all manufacturers used in the production of parenteral nutrition solutions were identified and collected. Three lots were collected for each identified product. Samples were quantitatively analyzed by Mayo Laboratories. These measured concentrations were then compared to the manufacturers' labeled concentration. RESULTS Large lot-to-lot and manufacturer-to-manufacturer differences were noted for all products. Measured aluminum concentrations were less than manufacturer-labeled values for all products. CONCLUSIONS The actual aluminum concentrations of all the parenteral nutrition solutions were significantly less than the aluminum content based on manufacturers' labels. These findings indicate that 1) the manufacturers should label their products with actual aluminum content at the time of product release rather than at the time of expiry, 2) that there are manufacturers whose products provide significantly less aluminum contamination than others, and 3) pharmacists can select products with the lowest amounts of aluminum contamination and reduce the aluminum exposure in their patients. PMID:22477831

  4. Use of low-cost aluminum in electric energy production

    NASA Astrophysics Data System (ADS)

    Zhuk, Andrey Z.; Sheindlin, Alexander E.; Kleymenov, Boris V.; Shkolnikov, Eugene I.; Lopatin, Marat Yu.

    Suppression of the parasitic corrosion while maintaining the electrochemical activity of the anode metal is one of the serious problems that affects the energy efficiency of aluminum-air batteries. The need to use high-purity aluminum or special aluminum-based alloys results in a significant increase in the cost of the anode, and thus an increase in the total cost of energy generated by the aluminum-air battery, which narrows the range of possible applications for this type of power source. This study considers the process of parasitic corrosion as a method for hydrogen production. Hydrogen produced in an aluminum-air battery by this way may be further employed in a hydrogen-air fuel cell (Hy-air FC) or in a heat engine, or it may be burnt to generate heat. Therefore, anode materials may be provided by commercially pure aluminum, commercially produced aluminum alloys, and secondary aluminum. These materials are much cheaper and more readily available than special anode alloys of aluminum and high-purity aluminum. The aim of present study is to obtain experimental data for comparison of energy and cost parameters of some commercially produced aluminum alloys, of high-purity aluminum, and of a special Al-ln anode alloy in the context of using these materials as anodes for an Al-air battery and for combined production of electrical power and hydrogen.

  5. Production of anhydrous aluminum chloride composition

    DOEpatents

    Vandergrift, G.F. III; Krumpelt, M.; Horwitz, E.P.

    1981-10-08

    A process is described for producing an anhydrous aluminum chloride composition from a water-based aluminous material such as a slurry of aluminum hydroxide in a multistage extraction process in which the aluminum ion is first extracted into an organic liquid containing an acidic extractant and then extracted from the organic phase into an alkali metal chloride or chlorides to form a melt containing a mixture of chlorides of alkali metal and aluminum. In the process, the organic liquid may be recycled. In addition, the process advantageously includes an electrolysis cell for producing metallic aluminum and the alkali metal chloride or chlorides may be recycled for extraction of the aluminum from the organic phase.

  6. Energy conservation in the primary aluminum and chlor-alkali industries

    SciTech Connect

    Not Available

    1980-10-01

    The primary aluminum and chlor-alkali industries together use nearly 13% of the electrical energy consumed by US industry. As part of its mission to promote energy conservation in basic US industries, the DOE surveys the present technological status of the major electrochemical industries and evaluates promising technological innovations that may lead to reduced energy requirements. This study provides technical and economic analyses in support of a government program of research and development in advanced electrolytic technology. This program is intended to supplement the development efforts directed toward energy savings by private industry. Sections II and III of this report cover aluminum and chlorine production processes only, since these two industries represent over 90% of the electrical energy requirements of all electrolytic industries in the United States. Section IV examines barriers to accelerated research and development by the electrolytic industries, and makes suggestions for government actions to overcome these barriers.

  7. Gross Primary Productivity

    NASA Technical Reports Server (NTRS)

    2002-01-01

    NASA's new Moderate-resolution Imaging Spectroradiometer (MODIS) allows scientists to gauge our planet's metabolism on an almost daily basis. GPP, gross primary production, is the technical term for plant photosynthesis. This composite image over the continental United States, acquired during the period March 26-April 10, 2000, shows regions where plants were more or less productive-i.e., where they 'inhaled' carbon dioxide and then used the carbon from photosynthesis to build new plant structures. This false-color image provides a map of how much carbon was absorbed out of the atmosphere and fixed within land vegetation. Areas colored blue show where plants used as much as 60 grams of carbon per square meter. Areas colored green and yellow indicate a range of anywhere from 40 to 20 grams of carbon absorbed per square meter. Red pixels show an absorption of less than 10 grams of carbon per square meter and white pixels (often areas covered by snow or masked as urban) show little or no absorption. This is one of a number of new measurements that MODIS provides to help scientists understand how the Earth's landscapes are changing over time. Scientists' goal is use of these GPP measurements to refine computer models to simulate how the land biosphere influences the natural cycles of water, carbon, and energy throughout the Earth system. The GPP will be an integral part of global carbon cycle source and sink analysis, an important aspect of Kyoto Protocol assessments. This image is the first of its kind from the MODIS instrument, which launched in December 1999 aboard the Terra spacecraft. MODIS began acquiring scientific data on February 24, 2000, when it first opened its aperture door. The MODIS instrument and Terra spacecraft are both managed by NASA's Goddard Space Flight Center, Greenbelt, MD. Image courtesy Steven Running, MODIS Land Group Member, University of Montana

  8. The crystallization processes in the aluminum particles production technology

    NASA Astrophysics Data System (ADS)

    Arkhipov, Vladimir; Bondarchuk, Sergey; Goldin, Victor; Zharova, Irina

    2015-01-01

    The physical and mathematical model of the crystallization process of liquid aluminum particles in the spray-jet of the ejection-type atomizer was proposed. The results of mathematical modeling of two-phase flow in the spray-jet and the crystallization process of fluid particles are given. The influence of the particle size, of the flow rate and the stagnation temperature gas in the ranges of industrial technology implemented for the production of powders aluminum of brands ASD, on the crystallization characteristics were investigated. The approximations of the characteristics of the crystallization process depending on the size of the aluminum particles on the basis of two approaches to the mathematical description of the process of crystallization of aluminum particles were obtained. The results allow to optimize the process parameters of ejection-type atomizer to produce aluminum particles with given morphology.

  9. 77 FR 2677 - National Emission Standards for Hazardous Air Pollutants: Primary Aluminum Reduction Plants...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-01-19

    ... Standards for Hazardous Air Pollutants: Primary Aluminum Reduction Plants'' is being extended for 12 days. DATES: Comments. The public comment period for the proposed rule published December 6, 2011, (76 FR... Aluminum Reduction Plants; Extension of Comment Period AGENCY: Environmental Protection Agency...

  10. Evaluation of tremor in aluminum production workers.

    PubMed

    Dick, R B; Krieg, E F; Sim, M A; Bernard, B P; Taylor, B T

    1997-01-01

    A cross-sectional study of 63 current and former aluminum potroom workers and 37 comparison workers was conducted to evaluate for evidence of neurological dysfunction, including tremor from long-term exposures to aluminum using sensitive quantitative measures of arm/hand and leg tremor. Signs of upper extremity tremor were also evaluated by neurological examination and compared with the quantitative measures of arm/hand tremor. Both arm/hand and leg tremor were measured using fatiguing test conditions, but no statistically significant differences due to exposure to aluminum were present between the potroom workers and the comparison workers. The neurological examination also showed no statistically significant differences between the groups on the evaluation of signs of tremor. These results do not support the findings of Best-Pettersen et al., who reported evidence of increased tremor in aluminum workers using the static steadiness test in the Halstead-Reitan battery. Differences between the studies that may have contributed to the contrasting results are discussed. In addition, techniques are presented for using microcomputer-controlled devices to evaluate tremor in both the visible (1-6 Hz) and nonvisible (7-18 Hz) frequencies of the tremor spectrum.

  11. 78 FR 20298 - Restoration and Compensation Determination Plan and Environmental Assessment: Aluminum Production...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-04-04

    ... Environmental Assessment: Aluminum Production Plants and Engine Manufacturer, St. Lawrence River, Massena, NY... resource injuries and service losses associated with the release of hazardous substances from two aluminum... included polychlorinated biphenyls (PCBs), polycyclic aromatic hydrocarbons (PAHs), aluminum, fluoride,...

  12. Reusing steel and aluminum components at end of product life.

    PubMed

    Cooper, Daniel R; Allwood, Julian M

    2012-09-18

    Reusing steel and aluminum components would reduce the need for new production, possibly creating significant savings in carbon emissions. Currently, there is no clearly defined set of strategies or barriers to enable assessment of appropriate component reuse; neither is it possible to predict future levels of reuse. This work presents a global assessment of the potential for reusing steel and aluminum components. A combination of top-down and bottom-up analyses is used to allocate the final destinations of current global steel and aluminum production to product types. A substantial catalogue has been compiled for these products characterizing key features of steel and aluminum components including design specifications, requirements in use, and current reuse patterns. To estimate the fraction of end-of-life metal components that could be reused for each product, the catalogue formed the basis of a set of semistructured interviews with industrial experts. The results suggest that approximately 30% of steel and aluminum used in current products could be reused. Barriers against reuse are examined, prompting recommendations for redesign that would facilitate future reuse.

  13. [The unbearable lightness of aluminum: the social and environmental impacts of Brazil's insertion in the primary aluminum global market].

    PubMed

    Henriques, Alen Batista; Porto, Marcelo Firpo Souza

    2013-11-01

    This article assesses aluminum production in Brazil and its social, environmental and public health impacts. The effects of the aluminum production chain challenge the idea of sustainable growth affirmed by business groups that operate in the sector. This article upholds the theory that the insertion of Brazil in the global aluminum market is part of a new configuration of the International Division of Labor (IDL), the polluting economic and highly energy dependent activities of which - as is the case of aluminum - have been moving to peripheral nations or emerging countries. The laws in such countries are less stringent, and similarly the environmental movements and the claims of the affected populations in the territories prejudiced in their rights to health, a healthy environment and culture are less influential. The competitiveness of this commodity is guaranteed in the international market, from the production of external factors such as environmental damage, deforestation, emissions of greenhouse gases and scenarios of environmental injustice. This includes undertakings in the construction of hydroelectric dams that expose traditional communities to situations involving the loss of their territories. PMID:24196888

  14. [The unbearable lightness of aluminum: the social and environmental impacts of Brazil's insertion in the primary aluminum global market].

    PubMed

    Henriques, Alen Batista; Porto, Marcelo Firpo Souza

    2013-11-01

    This article assesses aluminum production in Brazil and its social, environmental and public health impacts. The effects of the aluminum production chain challenge the idea of sustainable growth affirmed by business groups that operate in the sector. This article upholds the theory that the insertion of Brazil in the global aluminum market is part of a new configuration of the International Division of Labor (IDL), the polluting economic and highly energy dependent activities of which - as is the case of aluminum - have been moving to peripheral nations or emerging countries. The laws in such countries are less stringent, and similarly the environmental movements and the claims of the affected populations in the territories prejudiced in their rights to health, a healthy environment and culture are less influential. The competitiveness of this commodity is guaranteed in the international market, from the production of external factors such as environmental damage, deforestation, emissions of greenhouse gases and scenarios of environmental injustice. This includes undertakings in the construction of hydroelectric dams that expose traditional communities to situations involving the loss of their territories.

  15. Effects of anti-odor automobile air-conditioning system products on adherence of Serratia marcescens to aluminum.

    PubMed

    Drago, G K; Simmons, R B; Price, D L; Crow, S A; Ahearn, D G

    2002-12-01

    Sixteen commercial products for use in automobile air-conditioning systems (ACS), most designated for abatement of malodors presumably of microbial origin, were examined for their potential to inhibit attachment and to detach cells of the Gram-negative bacterium Serratia marcescens on aluminum sections. Numbers of attached cells were appreciably reduced (>60%) following immersion in three alcohol-type and two acrylic-coating-type products. Several products had essentially no effect on the attached cells. Most of the products indicated for alleviation of associated microbial odors from ACS provided only short-term effects. When products were coated onto aluminum prior to exposure to the cells, water-insoluble coatings appeared to provide more consistent inhibition of primary adherence of S. marcescens. The differences in degrees of primary adherence of a selected strain of S. marcescens to variously treated aluminum provided a rapid and reproducible assessment of potential antimicrobial efficacy of ACS products. PMID:12483481

  16. Aluminum: A neurotoxic product of acid rain

    SciTech Connect

    Martin, R.B.

    1994-07-01

    Two separate but converging concerns have resulted in an upsurge in research on aluminum ion in the past 15 years. Acid rain releases Al(III) from soils into fresh waters, where it is for the first time accessible to living organisms. Though long considered benign, Al(III) has recently been found to cause bone and neurological disorders, while its role in Alzheimer`s disease remains uncertain. The greater availability of Al(III), coupled with its demonstrated harmful effects, challenges chemists to describe its chemistry and biochemistry. Many interactions of Al(III) have been described, but several questions remain unsolved. A great deal of work not within the scope of this Account is described in several edited volumes. (This Account uses Al(III) as a generic term for the 3+ ion when a specific form is not indicated). 96 refs., 2 figs., 2 tabs.

  17. Fundamental studies on electrochemical production of dendrite-free aluminum and titanium-aluminum alloys

    NASA Astrophysics Data System (ADS)

    Pradhan, Debabrata

    A novel dendrite-free electrorefining of aluminum scrap was investigated by using AlCl3-1-Ethyl-3-methyl-imidazolium chloride (EMIC) ionic liquid electrolyte. Electrodeposition of aluminum were conducted on copper/aluminum cathodes at voltage of 1.5 V, temperatures (50-110°C), stirring rate (0-120 rpm), molar ratio (MR) of AlCl3:EMIC (1.25-2.0) and electrode surface modification (modified/unmodified). The study was focused to investigate the effect of process variables on deposit morphology, cathode current density and their role in production of dendrite-free aluminum. The deposits were characterized using scanning electron microscope (SEM), energy dispersive spectroscopy (EDS) and X-ray diffraction (XRD). Modified electrodes and stirring rate (60 rpm) eliminate dendritic deposition by reducing cathode overpotential below critical overpotential (etacrt≈ -0.54 V) for dendrite formation. Pure aluminum (>99%) was deposited with current efficiency of 84-99%. Chronoamperometry study was conducted using AlCl3-EMIC and AlCl3-1-Butyl-3-methyl-imidazolium chloride (BMIC) (MR = 1.65:1) at 90°C to understand the mechanism of aluminum electrodeposition and find out diffusion parameter of electroactive species Al2C 7-. It was concluded that electrodeposition of aluminum is a diffusion controlled instantaneous nucleation process and diffusion coefficient of Al2C7- was found to be 5.2-6.9 x 10-11 m2/s and 2.2 x 10-11 m2/s for AlCl3-EMIC and AlCl3-BMIC, respectively. A novel production route of Ti-Al alloys was investigated using AlCl 3-BMIC-TiCl4 (MR = 2:1:0.019) and AlCl3-BMIC (MR = 2:1) electrolytes at constant voltages of 1.5-3.0 V and temperatures (70-125°C). Ti sheet was used as anode and cathode. Characterization of electrodeposited Ti-Al alloys was carried out using SEM, EDS, XRD and inductively coupled plasma-optical emission spectrometer (ICP-OES). Effect of voltage and temperature on cathode current density, current efficiency, composition and morphology of Ti

  18. Primary productivity in the sea

    SciTech Connect

    Falkowski, P.G.

    1980-01-01

    Recent progress in primary productivity is discussed in the book based on 27 symposia texts and 19 poster abstracts. Most papers deal with particular cellular processes in pelagic phytoplankton and their relationship to whole plant photosynthesis and growth. In addition, presentations on the productivity of the seaweed, Laminaria, zooxanthellae and whole corals are included. Other articles discuss predictive modeling, new developments in remote sensing, nutrient regeneration within the sea, grazing effects, and carbon cycling. (JMT)

  19. 40 CFR 415.10 - Applicability; description of the aluminum chloride production subcategory.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... aluminum chloride production subcategory. 415.10 Section 415.10 Protection of Environment ENVIRONMENTAL... SOURCE CATEGORY Aluminum Chloride Production Subcategory § 415.10 Applicability; description of the aluminum chloride production subcategory. The provisions of this subpart are applicable to discharges...

  20. 40 CFR 415.20 - Applicability; description of the aluminum sulfate production subcategory.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... aluminum sulfate production subcategory. 415.20 Section 415.20 Protection of Environment ENVIRONMENTAL... SOURCE CATEGORY Aluminum Sulfate Production Subcategory § 415.20 Applicability; description of the aluminum sulfate production subcategory. The provisions of this subpart are applicable to discharges and...

  1. 40 CFR 415.20 - Applicability; description of the aluminum sulfate production subcategory.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... aluminum sulfate production subcategory. 415.20 Section 415.20 Protection of Environment ENVIRONMENTAL... SOURCE CATEGORY Aluminum Sulfate Production Subcategory § 415.20 Applicability; description of the aluminum sulfate production subcategory. The provisions of this subpart are applicable to discharges and...

  2. 40 CFR 415.10 - Applicability; description of the aluminum chloride production subcategory.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... aluminum chloride production subcategory. 415.10 Section 415.10 Protection of Environment ENVIRONMENTAL... SOURCE CATEGORY Aluminum Chloride Production Subcategory § 415.10 Applicability; description of the aluminum chloride production subcategory. The provisions of this subpart are applicable to discharges...

  3. 40 CFR 415.20 - Applicability; description of the aluminum sulfate production subcategory.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... aluminum sulfate production subcategory. 415.20 Section 415.20 Protection of Environment ENVIRONMENTAL... SOURCE CATEGORY Aluminum Sulfate Production Subcategory § 415.20 Applicability; description of the aluminum sulfate production subcategory. The provisions of this subpart are applicable to discharges and...

  4. 40 CFR 415.230 - Applicability; description of the aluminum fluoride production subcategory.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... aluminum fluoride production subcategory. 415.230 Section 415.230 Protection of Environment ENVIRONMENTAL... SOURCE CATEGORY Aluminum Fluoride Production Subcategory § 415.230 Applicability; description of the aluminum fluoride production subcategory. This subpart applies to discharges to waters of the United...

  5. 40 CFR 415.230 - Applicability; description of the aluminum fluoride production subcategory.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... aluminum fluoride production subcategory. 415.230 Section 415.230 Protection of Environment ENVIRONMENTAL... SOURCE CATEGORY Aluminum Fluoride Production Subcategory § 415.230 Applicability; description of the aluminum fluoride production subcategory. This subpart applies to discharges to waters of the United...

  6. 40 CFR 415.10 - Applicability; description of the aluminum chloride production subcategory.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... aluminum chloride production subcategory. 415.10 Section 415.10 Protection of Environment ENVIRONMENTAL... SOURCE CATEGORY Aluminum Chloride Production Subcategory § 415.10 Applicability; description of the aluminum chloride production subcategory. The provisions of this subpart are applicable to discharges...

  7. 40 CFR 415.10 - Applicability; description of the aluminum chloride production subcategory.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... aluminum chloride production subcategory. 415.10 Section 415.10 Protection of Environment ENVIRONMENTAL... SOURCE CATEGORY Aluminum Chloride Production Subcategory § 415.10 Applicability; description of the aluminum chloride production subcategory. The provisions of this subpart are applicable to discharges...

  8. 40 CFR 415.230 - Applicability; description of the aluminum fluoride production subcategory.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... aluminum fluoride production subcategory. 415.230 Section 415.230 Protection of Environment ENVIRONMENTAL... SOURCE CATEGORY Aluminum Fluoride Production Subcategory § 415.230 Applicability; description of the aluminum fluoride production subcategory. This subpart applies to discharges to waters of the United...

  9. 40 CFR 415.230 - Applicability; description of the aluminum fluoride production subcategory.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... aluminum fluoride production subcategory. 415.230 Section 415.230 Protection of Environment ENVIRONMENTAL... SOURCE CATEGORY Aluminum Fluoride Production Subcategory § 415.230 Applicability; description of the aluminum fluoride production subcategory. This subpart applies to discharges to waters of the United...

  10. 40 CFR 415.10 - Applicability; description of the aluminum chloride production subcategory.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... aluminum chloride production subcategory. 415.10 Section 415.10 Protection of Environment ENVIRONMENTAL... SOURCE CATEGORY Aluminum Chloride Production Subcategory § 415.10 Applicability; description of the aluminum chloride production subcategory. The provisions of this subpart are applicable to discharges...

  11. 40 CFR 415.20 - Applicability; description of the aluminum sulfate production subcategory.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... aluminum sulfate production subcategory. 415.20 Section 415.20 Protection of Environment ENVIRONMENTAL... SOURCE CATEGORY Aluminum Sulfate Production Subcategory § 415.20 Applicability; description of the aluminum sulfate production subcategory. The provisions of this subpart are applicable to discharges and...

  12. 40 CFR 415.20 - Applicability; description of the aluminum sulfate production subcategory.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... aluminum sulfate production subcategory. 415.20 Section 415.20 Protection of Environment ENVIRONMENTAL... SOURCE CATEGORY Aluminum Sulfate Production Subcategory § 415.20 Applicability; description of the aluminum sulfate production subcategory. The provisions of this subpart are applicable to discharges and...

  13. 40 CFR 415.230 - Applicability; description of the aluminum fluoride production subcategory.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... aluminum fluoride production subcategory. 415.230 Section 415.230 Protection of Environment ENVIRONMENTAL... SOURCE CATEGORY Aluminum Fluoride Production Subcategory § 415.230 Applicability; description of the aluminum fluoride production subcategory. This subpart applies to discharges to waters of the United...

  14. High-energy electron-induced damage production at room temperature in aluminum-doped silicon

    NASA Technical Reports Server (NTRS)

    Corbett, J. W.; Cheng, L. J.; Jaworowski, A.; Karins, J. P.; Lee, Y. H.; Lindstroem, L.; Mooney, P. M.; Oehrlen, G.; Wang, K. L.

    1979-01-01

    DLTS and EPR measurements are reported on aluminum-doped silicon that was irradiated at room temperature with high-energy electrons. Comparisons are made to comparable experiments on boron-doped silicon. Many of the same defects observed in boron-doped silicon are also observed in aluminum-doped silicon, but several others were not observed, including the aluminum interstitial and aluminum-associated defects. Damage production modeling, including the dependence on aluminum concentration, is presented.

  15. Neuropsychological deficit among elderly workers in aluminum production.

    PubMed

    Bast-Pettersen, R; Drabløs, P A; Goffeng, L O; Thomassen, Y; Torres, C G

    1994-05-01

    A cross-sectional study was conducted at a Norwegian primary aluminum plant. All workers aged 61-66 years were offered early retirement benefits. Among the workers, 47 met the study criteria and 38 (81%), comprising 14 potroom workers, 8 foundry workers, and 16 controls, volunteered to participate. They were tested with a neuropsychological test battery. Workers in potrooms with Søderberg electrolytic cells were found to show signs of impairment of the nervous system. A test for tremor discriminated significantly between the potroom group and the controls. There was a suggestion of increased risk of impaired visuospatial organization and a tendency to a decline in psychomotor tempo in the potroom workers. We suggest that the above findings may be related to long-term occupational exposure in the potroom, and further to chronic low-dose exposure to aluminum.

  16. 75 FR 66798 - Ormet Primary Aluminum Corporation Including On-Site Temporary Workers, Hannibal, OH; Notice of...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-10-29

    ... negative determination was published in the Federal Register on March 12, 2010 (75 FR 11925). To support... Employment and Training Administration Ormet Primary Aluminum Corporation Including On-Site Temporary Workers... regarding eligibility for workers and former workers of Ormet Primary Aluminum Corporation, including...

  17. Continuous Casting for Aluminum Sheet: a Product Perspective

    NASA Astrophysics Data System (ADS)

    Sanders, Robert E.

    2012-02-01

    Continuous casting processes have been used successfully for more than 50 years to reduce the cost of manufacturing a variety of aluminum rolled products. Approximately 25% of North American flat-rolled sheet and foil is sourced from twin-roll cast or slab cast processes. Twin roll-casters provide a cost-effective solution for producing foil and light-gauge sheet from relatively low-alloyed aluminum (1xxx and 8xxx alloys). Slab casters, particularly Hazelett twin-belt machines, are well utilized in the production of 3xxx or 5xxx painted building products which require moderate strength and good corrosion resistance. Both foil and painted sheet are cost-sensitive commodity products with well-known metallurgical and quality requirements. There have been extensive trials and modest successes with continuous cast can stock and automotive sheet. However, they have not been widely adopted commercially due to generally lower levels of surface quality and formability compared with sheet produced from scalped direct chill (DC) cast ingot. The metallurgical requirements for can and auto sheet are considered in more detail with emphasis on the microstructural features which limit their application, e.g., particle distribution, grain size, and texture. Looking forward, slab casting offers the most viable opportunity for producing strong (i.e., higher alloy content), formable structural auto sheet with acceptable surface quality.

  18. Aluminum base alloy powder metallurgy process and product

    NASA Technical Reports Server (NTRS)

    Paris, Henry G. (Inventor)

    1986-01-01

    A metallurgical method including cooling molten aluminum particles and consolidating resulting solidified particles into a multiparticle body, wherein the improvement comprises the provision of greater than 0.15% of a metal which diffuses in the aluminum solid state at a rate less than that of Mn. Aluminum containing greater than 0.15% of a metal which diffuses in the aluminum solid state at a rate less than that of Mn.

  19. Assessment of the magnesium primary production technology. Final report

    SciTech Connect

    Flemings, M.C.; Kenney, G.B.; Sadoway, D.R.; Clark, J.P.; Szekely, J.

    1981-02-01

    At current production levels, direct energy savings achievable in primary magnesium production are 1.2 milliquads of energy per annum. Were magnesium to penetrate the automotive market to an average level of 50 pounds per vehicle, the resultant energy savings at the production stage would be somewhat larger, but the resulting savings in gasoline would conserve an estimated 325 milliquads of energy per year. The principal barrier to more widespread use of magnesium in the immediate future is its price. A price reduction of magnesium of 10% would lead to widespread conversion of aluminum die and permanent mold castings to magnesium. This report addresses the technology of electrolytic and thermic magnesium production and the economics of expanded magnesium production and use.

  20. Production of sodium-22 from proton irradiated aluminum

    DOEpatents

    Taylor, Wayne A.; Heaton, Richard C.; Jamriska, David J.

    1996-01-01

    A process for selective separation of sodium-22 from a proton irradiated minum target including dissolving a proton irradiated aluminum target in hydrochloric acid to form a first solution including aluminum ions and sodium ions, separating a portion of the aluminum ions from the first solution by crystallization of an aluminum salt, contacting the remaining first solution with an anion exchange resin whereby ions selected from the group consisting of iron and copper are selectively absorbed by the anion exchange resin while aluminum ions and sodium ions remain in solution, contacting the solution with an cation exchange resin whereby aluminum ions and sodium ions are adsorbed by the cation exchange resin, and, contacting the cation exchange resin with an acid solution capable of selectively separating the adsorbed sodium ions from the cation exchange resin while aluminum ions remain adsorbed on the cation exchange resin is disclosed.

  1. 77 FR 16987 - National Emission Standards for Hazardous Air Pollutants: Secondary Aluminum Production

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-03-23

    ... for hazardous air pollutants for secondary aluminum production (77 FR 8576). The EPA is extending the... Aluminum Production AGENCY: Environmental Protection Agency (EPA). ACTION: Notice of extension of public..., as well as review the test data for Group I furnaces. DATES: Comments. The public comment period...

  2. Global marine primary production constrains fisheries catches.

    PubMed

    Chassot, Emmanuel; Bonhommeau, Sylvain; Dulvy, Nicholas K; Mélin, Frédéric; Watson, Reg; Gascuel, Didier; Le Pape, Olivier

    2010-04-01

    Primary production must constrain the amount of fish and invertebrates available to expanding fisheries; however the degree of limitation has only been demonstrated at regional scales to date. Here we show that phytoplanktonic primary production, estimated from an ocean-colour satellite (SeaWiFS), is related to global fisheries catches at the scale of Large Marine Ecosystems, while accounting for temperature and ecological factors such as ecosystem size and type, species richness, animal body size, and the degree and nature of fisheries exploitation. Indeed we show that global fisheries catches since 1950 have been increasingly constrained by the amount of primary production. The primary production appropriated by current global fisheries is 17-112% higher than that appropriated by sustainable fisheries. Global primary production appears to be declining, in some part due to climate variability and change, with consequences for the near future fisheries catches.

  3. Production of Magnesium and Aluminum-Magnesium Alloys from Recycled Secondary Aluminum Scrap Melts

    NASA Astrophysics Data System (ADS)

    Gesing, Adam J.; Das, Subodh K.; Loutfy, Raouf O.

    2016-02-01

    An experimental proof of concept was demonstrated for a patent-pending and trademark-pending RE12™ process for extracting a desired amount of Mg from recycled scrap secondary Al melts. Mg was extracted by electrorefining, producing a Mg product suitable as a Mg alloying hardener additive to primary-grade Al alloys. This efficient electrorefining process operates at high current efficiency, high Mg recovery and low energy consumption. The Mg electrorefining product can meet all the impurity specifications with subsequent melt treatment for removing alkali contaminants. All technical results obtained in the RE12™ project indicate that the electrorefining process for extraction of Mg from Al melt is technically feasible. A techno-economic analysis indicates high potential profitability for applications in Al foundry alloys as well as beverage—can and automotive—sheet alloys. The combination of technical feasibility and potential market profitability completes a successful proof of concept. This economical, environmentally-friendly and chlorine-free RE12™ process could be disruptive and transformational for the Mg production industry by enabling the recycling of 30,000 tonnes of primary-quality Mg annually.

  4. Primary magnesium production costs for automotive applications

    NASA Astrophysics Data System (ADS)

    Das, Sujit

    2008-11-01

    Focusing on primary magnesium production cost estimates, this paper provides a forecast of the long-term competitiveness of magnesium in automotive applications. Competing magnesium production technologies are considered, with particular emphasis on the long-term viability of cheap supplies using Chinese production technology. Also considered are two yet-to-be commercialized production processes.

  5. Energy Assessment Helps Kaiser Aluminum Save Energy and Improve Productivity

    SciTech Connect

    2008-07-01

    The Kaiser Aluminum plant in Sherman, Texas, adjusted controls and made repairs to a furnace for a simple payback of 1 month. Kaiser adopted DOE's Process Heating Assessment and Survey Tool (PHAST) software as the corporate diagnostic tool and has used it to evaluate process heating systems at five other aluminum plants.

  6. Electrolytic production of high purity aluminum using inert anodes

    DOEpatents

    Ray, Siba P.; Liu, Xinghua; Weirauch, Jr., Douglas A.

    2001-01-01

    A method of producing commercial purity aluminum in an electrolytic reduction cell comprising inert anodes is disclosed. The method produces aluminum having acceptable levels of Fe, Cu and Ni impurities. The inert anodes used in the process preferably comprise a cermet material comprising ceramic oxide phase portions and metal phase portions.

  7. Electrolytic production of high purity aluminum using ceramic inert anodes

    DOEpatents

    Ray, Siba P.; Liu, Xinghua; Weirauch, Douglas A.; DiMilia, Robert A.; Dynys, Joseph M.; Phelps, Frankie E.; LaCamera, Alfred F.

    2002-01-01

    A method of producing commercial purity aluminum in an electrolytic reduction cell comprising ceramic inert anodes is disclosed. The method produces aluminum having acceptable levels of Fe, Cu and Ni impurities. The ceramic inert anodes used in the process may comprise oxides containing Fe and Ni, as well as other oxides, metals and/or dopants.

  8. Aluminum Elicits Exocellular Phosphatidylethanolamine Production in Pseudomonas fluorescens

    PubMed Central

    Appanna, V. D.; Pierre, M. S.

    1996-01-01

    Pseudomonas fluorescens ATCC 13525 was found to grow in a minimal mineral medium supplemented with millimolar amounts of aluminum, a known environmental toxicant. During the stationary phase of growth, the trivalent metal was localized in a phosphatidylethanolamine (PE)-containing residue. The concentration of PE in pellets ranged from 1.7 to 13.9 mg ml of culture(sup-1) in media supplemented with 1 to 30 mM aluminum. Although the gelatinous residue was observed during the stationary phase of growth, ultracentrifugation and dialysis experiments revealed that PE was produced from earlier stages of incubation and was associated with aluminum. A sharp diminution in the levels of PE and aluminum in the spent fluid was concomitant with the formation of the insoluble deposit. The aluminum content of the soluble cellular fraction increased during growth and reached an optimum of 1.85 mM of test metal at 45 h in cultures with 15 mM aluminum. Further incubation, however, led to a marked decrease in the cellular aluminum content, and during the stationary phase of growth, only trace amounts of the trivalent metal were detected in this fraction. When 45-h cells were incubated in fresh citrate medium, most of the intracellular aluminum was secreted in the spent fluid and citrate was rapidly consumed. Aluminum efflux was also observed in cultures in which d-glucose was substituted for citrate. However, no efflux of this trivalent metal was evident in media devoid of either citrate or d-glucose. Scanning electron microscopic studies and X-ray energy-dispersive analyses of the dialyzed supernatant aided in the visualization of nodule-like aluminum- and phosphorus-rich bodies associated with thread-like carbon-, oxygen-, and phosphorus-containing structures. Transmission electron microscopic and electron energy loss spectroscopic analyses revealed the presence of aluminum within bacteria after 45 h of incubation. Cells harvested after aluminum insolubilization did not shown

  9. Primary production in Southern Ocean waters

    NASA Astrophysics Data System (ADS)

    Arrigo, Kevin R.; Worthen, Denise; Schnell, Anthony; Lizotte, Michael P.

    1998-07-01

    The Southern Ocean forms a link between major ocean basins, is the site of deep and intermediate water ventilation, and is one of the few areas where macronutrients are underutilized by phytoplankton. Paradoxically, prior estimates of annual primary production are insufficient to support the Antarctic food web. Here we present results from a primary production algorithm based upon monthly climatological phytoplankton pigment concentrations from the coastal zone color scanner (CZCS). Phytoplankton production was forced using monthly temperature profiles and a radiative transfer model that computed changes in photosynthetically usable radiation at each CZCS pixel location. Average daily productivity (g C m-2 d-1) and total monthly production (Tg C month-1) were calculated for each of five geographic sectors (defined by longitude) and three ecological provinces (defined by sea ice coverage and bathymetry as the pelagic province, the marginal ice zone, and the shelf). Annual primary production in the Southern Ocean (south of 50°S) was calculated to be 4414 Tg C yr-1, 4-5 times higher than previous estimates made from in situ data. Primary production was greatest in the month of December (816 Tg C month-1) and in the pelagic province (contributing 88.6% of the annual primary production). Because of their small size the marginal ice zone (MIZ) and the shelf contributed only 9.5% and 1.8%, respectively, despite exhibiting higher daily production rates. The Ross Sea was the most productive region, accounting for 28% of annual production. The fourfold increase in the estimate of primary production for the Southern Ocean likely makes the notion of an "Antarctic paradox" (primary production insufficient to support the populations of Southern Ocean grazers, including krill, copepods, microzooplankton, etc.) obsolete.

  10. Characterization of salt cake from secondary aluminum production.

    PubMed

    Huang, Xiao-Lan; Badawy, Amro El; Arambewela, Mahendranath; Ford, Robert; Barlaz, Morton; Tolaymat, Thabet

    2014-05-30

    Salt cake is a major waste component generated from the recycling of secondary aluminum processing (SAP) waste. Worldwide, the aluminum industry produces nearly 5 million tons of waste annually and the end-of-life management of these wastes is becoming a challenge in the U.S. and elsewhere. In this study, the mineral phases, metal content and metal leachability of 39 SAP waste salt cake samples collected from 10 different facilities across the U.S. were determined. The results showed that aluminum (Al), aluminum oxide, aluminum nitride and its oxides, spinel and elpasolite are the dominant aluminum mineral phases in salt cake. The average total Al content was 14% (w/w). The overall percentage of the total leachable Al in salt cake was 0.6% with approximately 80% of the samples leaching at a level less than 1% of the total aluminum content. The extracted trace metal concentrations in deionized water were relatively low (μgL(-1) level). The toxicity characteristic leaching procedure (TCLP) was employed to further evaluate leachability and the results indicated that the leached concentrations of toxic metals from salt cake were much lower than the EPA toxicity limit set by USEPA.

  11. The Aluminum Smelting Process

    PubMed Central

    2014-01-01

    This introduction to the industrial primary aluminum production process presents a short description of the electrolytic reduction technology, the history of aluminum, and the importance of this metal and its production process to modern society. Aluminum's special qualities have enabled advances in technologies coupled with energy and cost savings. Aircraft capabilities have been greatly enhanced, and increases in size and capacity are made possible by advances in aluminum technology. The metal's flexibility for shaping and extruding has led to architectural advances in energy-saving building construction. The high strength-to-weight ratio has meant a substantial reduction in energy consumption for trucks and other vehicles. The aluminum industry is therefore a pivotal one for ecological sustainability and strategic for technological development. PMID:24806722

  12. The aluminum smelting process.

    PubMed

    Kvande, Halvor

    2014-05-01

    This introduction to the industrial primary aluminum production process presents a short description of the electrolytic reduction technology, the history of aluminum, and the importance of this metal and its production process to modern society. Aluminum's special qualities have enabled advances in technologies coupled with energy and cost savings. Aircraft capabilities have been greatly enhanced, and increases in size and capacity are made possible by advances in aluminum technology. The metal's flexibility for shaping and extruding has led to architectural advances in energy-saving building construction. The high strength-to-weight ratio has meant a substantial reduction in energy consumption for trucks and other vehicles. The aluminum industry is therefore a pivotal one for ecological sustainability and strategic for technological development.

  13. Cathodic phenomena in aluminum electrowinning

    NASA Astrophysics Data System (ADS)

    Bouteillon, J.; Poignet, J. C.; Rameau, J. J.

    1993-02-01

    Although aluminum is one of the world's highest production-volume primary metals, it is particularly costly to produce for a variety of factors, not the least of which are the expenses associated with electrolytic reduction. Based on the scale of global aluminum processing, even minor improvements in the electrowinning technology can result in significant savings of resources. Thus, from this perspective, the following reviews recent studies of cathodic phenomena in aluminum electrowinning.

  14. Primary and secondary creep in aluminum alloys as a solid state transformation

    NASA Astrophysics Data System (ADS)

    Fernández, R.; Bruno, G.; González-Doncel, G.

    2016-08-01

    Despite the massive literature and the efforts devoted to understand the creep behavior of aluminum alloys, a full description of this phenomenon on the basis of microstructural parameters and experimental conditions is, at present, still missing. The analysis of creep is typically carried out in terms of the so-called steady or secondary creep regime. The present work offers an alternative view of the creep behavior based on the Orowan dislocation dynamics. Our approach considers primary and secondary creep together as solid state isothermal transformations, similar to recrystallization or precipitation phenomena. In this frame, it is shown that the Johnson-Mehl-Avrami-Kolmogorov equation, typically used to analyze these transformations, can also be employed to explain creep deformation. The description is fully compatible with present (empirical) models of steady state creep. We used creep curves of commercially pure Al and ingot AA6061 alloy at different temperatures and stresses to validate the proposed model.

  15. 48 CFR 252.216-7000 - Economic price adjustment-basic steel, aluminum, brass, bronze, or copper mill products.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ...-basic steel, aluminum, brass, bronze, or copper mill products. 252.216-7000 Section 252.216-7000 Federal... adjustment—basic steel, aluminum, brass, bronze, or copper mill products. As prescribed in 216.203-4-70(a), use the following clause: Economic Price Adjustment—Basic Steel, Aluminum, Brass, Bronze, or...

  16. 48 CFR 252.216-7000 - Economic price adjustment-basic steel, aluminum, brass, bronze, or copper mill products.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ...-basic steel, aluminum, brass, bronze, or copper mill products. 252.216-7000 Section 252.216-7000 Federal... adjustment—basic steel, aluminum, brass, bronze, or copper mill products. As prescribed in 216.203-4-70(a)(1), use the following clause: Economic Price Adjustment—Basic Steel, Aluminum, Brass, Bronze, or...

  17. 48 CFR 252.216-7007 - Economic price adjustment-basic steel, aluminum, brass, bronze, or copper mill products...

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ...-basic steel, aluminum, brass, bronze, or copper mill products-representation. 252.216-7007 Section 252....216-7007 Economic price adjustment—basic steel, aluminum, brass, bronze, or copper mill products... Steel, Aluminum, Brass, Bronze, or Copper Mill Products—Representation (MAR 2012) (a) Definitions....

  18. 48 CFR 252.216-7000 - Economic price adjustment-basic steel, aluminum, brass, bronze, or copper mill products.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ...-basic steel, aluminum, brass, bronze, or copper mill products. 252.216-7000 Section 252.216-7000 Federal... adjustment—basic steel, aluminum, brass, bronze, or copper mill products. As prescribed in 216.203-4-70(a), use the following clause: Economic Price Adjustment—Basic Steel, Aluminum, Brass, Bronze, or...

  19. 48 CFR 252.216-7007 - Economic price adjustment-basic steel, aluminum, brass, bronze, or copper mill products...

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ...-basic steel, aluminum, brass, bronze, or copper mill products-representation. 252.216-7007 Section 252....216-7007 Economic price adjustment—basic steel, aluminum, brass, bronze, or copper mill products... Steel, Aluminum, Brass, Bronze, or Copper Mill Products—Representation (MAR 2012) (a) Definitions....

  20. 48 CFR 252.216-7007 - Economic price adjustment-basic steel, aluminum, brass, bronze, or copper mill products...

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ...-basic steel, aluminum, brass, bronze, or copper mill products-representation. 252.216-7007 Section 252....216-7007 Economic price adjustment—basic steel, aluminum, brass, bronze, or copper mill products... Steel, Aluminum, Brass, Bronze, or Copper Mill Products—Representation (MAR 2012) (a) Definitions....

  1. 48 CFR 252.216-7000 - Economic price adjustment-basic steel, aluminum, brass, bronze, or copper mill products.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ...-basic steel, aluminum, brass, bronze, or copper mill products. 252.216-7000 Section 252.216-7000 Federal... adjustment—basic steel, aluminum, brass, bronze, or copper mill products. As prescribed in 216.203-4-70(a)(1), use the following clause: Economic Price Adjustment—Basic Steel, Aluminum, Brass, Bronze, or...

  2. 48 CFR 252.216-7000 - Economic price adjustment-basic steel, aluminum, brass, bronze, or copper mill products.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ...-basic steel, aluminum, brass, bronze, or copper mill products. 252.216-7000 Section 252.216-7000 Federal... adjustment—basic steel, aluminum, brass, bronze, or copper mill products. As prescribed in 216.203-4-70(a)(1), use the following clause: Economic Price Adjustment—Basic Steel, Aluminum, Brass, Bronze, or...

  3. β-Amyloid-aluminum complex alters cytoskeletal stability and increases ROS production in cortical neurons.

    PubMed

    Bolognin, Silvia; Zatta, Paolo; Lorenzetto, Erika; Valenti, Maria Teresa; Buffelli, Mario

    2013-04-01

    Several lines of evidence have supported the potential involvement of metal ions in the etiology of Alzheimer's Disease (AD). However, the molecular mechanisms underlying this interaction are still partially unknown. Previous work from our laboratory has shown that β-amyloid peptide (Aβ) aggregation was strongly influenced by the conjugation of the peptide with few metal ions (aluminum, copper, zinc, and iron) that are found in high concentrations in the senile plaque core. The binding of aluminum (Al) to Aβ specifically stabilized the peptide in an oligomeric conformation. Here, we show that the aggregation of Aβ-Al was boosted by sodium dodecyl sulfate, a detergent that mimics some characteristics of biological membrane, suggesting a potential role for membrane components in the Aβ aggregation process. Notably, we also found that Aβ-Al caused mitochondrial dysfunction and reactive oxygen species production in primary cortical neurons. Aβ-Al strongly promoted also alterations in cytoskeleton network as shown by the increased F-actin expression and the occurrence of neuritic beading. Interestingly, the neurotoxic effect of this metal complex was associated with a decreased mRNA expression of ubiquitin thiolesterase, an ubiquitin-dependent protein involved in catabolic process, and by the increased expression of glutaminyl cyclase, responsible for pathological post-translational modification of Aβ. These results suggest that, in neuronal cells, Aβ-Al can induce relevant detrimental changes that resemble pathological hallmarks of AD. PMID:23416043

  4. Variability in primary productivity determines metapopulation dynamics

    PubMed Central

    2016-01-01

    Temporal variability in primary productivity can change habitat quality for consumer species by affecting the energy levels available as food resources. However, it remains unclear how habitat-quality fluctuations may determine the dynamics of spatially structured populations, where the effects of habitat size, quality and isolation have been customarily assessed assuming static habitats. We present the first empirical evaluation on the effects of stochastic fluctuations in primary productivity—a major outcome of ecosystem functions—on the metapopulation dynamics of a primary consumer. A unique 13-year dataset from an herbivore rodent was used to test the hypothesis that inter-annual variations in primary productivity determine spatiotemporal habitat occupancy patterns and colonization and extinction processes. Inter-annual variability in productivity and in the growing season phenology significantly influenced habitat colonization patterns and occupancy dynamics. These effects lead to changes in connectivity to other potentially occupied habitat patches, which then feed back into occupancy dynamics. According to the results, the dynamics of primary productivity accounted for more than 50% of the variation in occupancy probability, depending on patch size and landscape configuration. Evidence connecting primary productivity dynamics and spatiotemporal population processes has broad implications for metapopulation persistence in fluctuating and changing environments. PMID:27053739

  5. Carbonaceous cathode with enhanced wettability for aluminum production

    DOEpatents

    Keller, Rudolf; Gatty, David G.; Barca, Brian J.

    2003-09-09

    A method of preparing carbonaceous blocks or bodies for use in a cathode in an electrolytic cell for producing aluminum wherein the cell contains an electrolyte and has molten aluminum contacting the cathode, the cathode having improved wettability with molten aluminum. The method comprises the steps of providing a carbonaceous block and a boron oxide containing melt. The carbonaceous block is immersed in the melt and pressure is applied to the melt to impregnate the melt into pores in the block. Thereafter, the carbonaceous block is withdrawn from the melt, the block having boron oxide containing melt intruded into pores therein, the boron oxide capable of reacting with a source of titanium or zirconium or like metal to form titanium or zirconium diboride during heatup or operation of said cell.

  6. Electrolytic Cell For Production Of Aluminum Employing Planar Anodes.

    DOEpatents

    Barnett, Robert J.; Mezner, Michael B.; Bradford, Donald R

    2004-10-05

    A method of producing aluminum in an electrolytic cell containing alumina dissolved in an electrolyte, the method comprising providing a molten salt electrolyte having alumina dissolved therein in an electrolytic cell. A plurality of anodes and cathodes having planar surfaces are disposed in a generally vertical orientation in the electrolyte, the anodes and cathodes arranged in alternating or interleaving relationship to provide anode planar surfaces disposed opposite cathode planar surfaces, the anode comprised of carbon. Electric current is passed through anodes and through the electrolyte to the cathodes depositing aluminum at the cathodes and forming carbon containing gas at the anodes.

  7. Chemicals: UV-curable coating for aluminum can production

    SciTech Connect

    1999-09-29

    Fact sheet on curing aluminum can coatings written for the NICE3 Program. Coors Brewing Company has been using ultraviolet (UV) light curing technology on its aluminum beverage cans for 25 years. The company is now looking to share its cost-saving technology with other aluminum can producers. Traditional curing methods for creating external decorations on cans rely on convective-heat ovens to cure ink and over-varnish coatings. These thermal-curing methods require large amounts of energy and money, and can have unintended environmental impacts. Coors' technique uses coating materials that cure when exposed to UV light, thereby eliminating the expensive heat treatments used by conventional coating methods. Additionally, the UV-coating process creates much lower emissions and a smaller pollution waste stream than rival thermal processes because it requires much less solvent than thermal processes. This technology can be used not only in the aluminum can industry, but in the automotive, airline, wood, paper, and plastics industries, as well.

  8. Comparing Laser Welding Technologies with Friction Stir Welding for Production of Aluminum Tailor-Welded Blanks

    SciTech Connect

    Hovanski, Yuri; Carsley, John; Carlson, Blair; Hartfield-Wunsch, Susan; Pilli, Siva Prasad

    2014-01-15

    A comparison of welding techniques was performed to determine the most effective method for producing aluminum tailor-welded blanks for high volume automotive applications. Aluminum sheet was joined with an emphasis on post weld formability, surface quality and weld speed. Comparative results from several laser based welding techniques along with friction stir welding are presented. The results of this study demonstrate a quantitative comparison of weld methodologies in preparing tailor-welded aluminum stampings for high volume production in the automotive industry. Evaluation of nearly a dozen welding variations ultimately led to down selecting a single process based on post-weld quality and performance.

  9. The association between aluminum-containing products and Alzheimer's disease.

    PubMed

    Graves, A B; White, E; Koepsell, T D; Reifler, B V; van Belle, G; Larson, E B

    1990-01-01

    The association between exposure to aluminum through the lifetime use of antiperspirants and antacids and Alzheimer's disease (AD) was explored in a case-control study of 130 matched pairs. Cases were clinically diagnosed between January 1980 and June 1985 at two geriatric psychiatric clinics in Seattle, Wash. Controls were friends or non-blood relatives of the case. Subjects were matched by age, sex, and the relationship between the case and his or her surrogate. For all antiperspirant/deodorant use, regardless of aluminum content, there was no association with AD (adjusted odds ratio (OR) = 1.2, 95% CI = 0.6-2.4). For aluminum-containing antiperspirants, the overall adjusted OR was 1.6 (95% CI = 1.04-2.4) with a trend toward a higher risk with increasing frequency of use (p for trend = 0.03), the adjusted OR in the highest tertile being 3.2. For antacids regardless of aluminum content, the overall adjusted OR was 3.1 (95% CI = 1.2-7.9). Here, a steep dose-response gradient was found (p for trend = 0.009), with an adjusted OR for the highest tertile of 11.7. However, when only aluminum-containing antacids were analyzed, the overall adjusted OR was only 0.7 (95% CI = 0.3-2.0) and there was no significant dose-response trend. These results are provocative but inconclusive due to methodologic problems relating to the necessary use of surrogate respondents and the long time period of potential exposure for this dementing disease. PMID:2319278

  10. Aluminum titanate - methods of production, microstructure and properties (review)

    SciTech Connect

    Tarasovskii, V.P.; Lukin, E.S.

    1986-01-01

    The development of science and technology in certain cases requires the use of materials with low coefficients of thermal linear expansion. At present, fused quartz, spodumene, and cordierite are used for these purposes. In contrast to cordierite and other silicates, aluminum titanate Al/sub 2/TiO/sub 5/ has a comparatively high melting point 1860 degrees C. This means it can be considered that the compound may be used to obtain ceramics having low alpha values and at the same time quite high service temperatures. The results obtained for specimens prepared by hot pressing confirm the hypothesis about the possibility in principle of creating ceramics from aluminum titanate with higher strength values than are known at the present time. The main approach to solving this problem is to investigate the influence of alloying additives on the microstructure of ceramics made of Al/sub 2/TiO/sub 5/.

  11. Primary Productivity in Meduxnekeag River, Maine, 2005

    USGS Publications Warehouse

    Goldstein, Robert M.; Schalk, Charles W.; Kempf, Joshua P.

    2009-01-01

    During August and September 2005, dissolved oxygen, temperature, pH, specific conductance, streamflow, and light intensity (LI) were determined continuously at six sites defining five reaches on Meduxnekeag River above and below Houlton, Maine. These data were collected as input for a dual-station whole-stream metabolism model to evaluate primary productivity in the river above and below Houlton. The river receives nutrients and organic matter from tributaries and the Houlton wastewater treatment plant (WWTP). Model output estimated gross and net primary productivity for each reach. Gross primary productivity (GPP) varied in each reach but was similar and positive among the reaches. GPP was correlated to LI in the four reaches above the WWTP but not in the reach below. Net primary productivity (NPP) decreased in each successive downstream reach and was negative in the lowest two reaches. NPP was weakly related to LI in the upper two reaches and either not correlated or negatively correlated in the lower three reaches. Relations among GPP, NPP, and LI indicate that the system is heterotrophic in the downstream reaches. The almost linear decrease in NPP (the increase in metabolism and respiration) indicates a cumulative effect of inputs of nutrients and organic matter from tributaries that drain agricultural land, the town of Houlton, and the discharges from the WWTP.

  12. QUANTIFYING UNCERTAINTY IN NET PRIMARY PRODUCTION MEASUREMENTS

    EPA Science Inventory

    Net primary production (NPP, e.g., g m-2 yr-1), a key ecosystem attribute, is estimated from a combination of other variables, e.g. standing crop biomass at several points in time, each of which is subject to errors in their measurement. These errors propagate as the variables a...

  13. Identification of the primary lesion of toxic aluminum in plant roots.

    PubMed

    Kopittke, Peter M; Moore, Katie L; Lombi, Enzo; Gianoncelli, Alessandra; Ferguson, Brett J; Blamey, F Pax C; Menzies, Neal W; Nicholson, Timothy M; McKenna, Brigid A; Wang, Peng; Gresshoff, Peter M; Kourousias, George; Webb, Richard I; Green, Kathryn; Tollenaere, Alina

    2015-04-01

    Despite the rhizotoxicity of aluminum (Al) being identified over 100 years ago, there is still no consensus regarding the mechanisms whereby root elongation rate is initially reduced in the approximately 40% of arable soils worldwide that are acidic. We used high-resolution kinematic analyses, molecular biology, rheology, and advanced imaging techniques to examine soybean (Glycine max) roots exposed to Al. Using this multidisciplinary approach, we have conclusively shown that the primary lesion of Al is apoplastic. In particular, it was found that 75 µm Al reduced root growth after only 5 min (or 30 min at 30 µm Al), with Al being toxic by binding to the walls of outer cells, which directly inhibited their loosening in the elongation zone. An alteration in the biosynthesis and distribution of ethylene and auxin was a second, slower effect, causing both a transient decrease in the rate of cell elongation after 1.5 h but also a longer term gradual reduction in the length of the elongation zone. These findings show the importance of focusing on traits related to cell wall composition as well as mechanisms involved in wall loosening to overcome the deleterious effects of soluble Al.

  14. Identification of the Primary Lesion of Toxic Aluminum in Plant Roots1[OPEN

    PubMed Central

    Kopittke, Peter M.; Moore, Katie L.; Lombi, Enzo; Gianoncelli, Alessandra; Ferguson, Brett J.; Blamey, F. Pax C.; Menzies, Neal W.; Nicholson, Timothy M.; McKenna, Brigid A.; Wang, Peng; Gresshoff, Peter M.; Kourousias, George; Webb, Richard I.; Green, Kathryn; Tollenaere, Alina

    2015-01-01

    Despite the rhizotoxicity of aluminum (Al) being identified over 100 years ago, there is still no consensus regarding the mechanisms whereby root elongation rate is initially reduced in the approximately 40% of arable soils worldwide that are acidic. We used high-resolution kinematic analyses, molecular biology, rheology, and advanced imaging techniques to examine soybean (Glycine max) roots exposed to Al. Using this multidisciplinary approach, we have conclusively shown that the primary lesion of Al is apoplastic. In particular, it was found that 75 µm Al reduced root growth after only 5 min (or 30 min at 30 µm Al), with Al being toxic by binding to the walls of outer cells, which directly inhibited their loosening in the elongation zone. An alteration in the biosynthesis and distribution of ethylene and auxin was a second, slower effect, causing both a transient decrease in the rate of cell elongation after 1.5 h but also a longer term gradual reduction in the length of the elongation zone. These findings show the importance of focusing on traits related to cell wall composition as well as mechanisms involved in wall loosening to overcome the deleterious effects of soluble Al. PMID:25670815

  15. ASR prevention — Effect of aluminum and lithium ions on the reaction products

    SciTech Connect

    Leemann, Andreas; Alahrache, Salaheddine; Winnefeld, Frank

    2015-10-15

    In spite of the recent progress in the understanding of the mechanisms enabling aluminum-containing SCM like metakaolin and added LiNO{sub 3} to limit the extent of ASR in mortar and concrete, some gaps still remain. They concern mainly the effect of aluminum-containing SCM on the formed ASR products and the influence of aggregate characteristics on the effectiveness of LiNO{sub 3}. In this study, a model system, concrete and mortar were investigated by pore solution analysis, TGA, XRD, NMR, SEM combined with EDX and ToF-SIMS to address these questions. The amount of aluminum present in the pore solution of concrete and mortar is only able to slow down SiO{sub 2} dissolution but not to alter morphology, structure and composition of the reaction products. LiNO{sub 3} can suppress ASR by forming dense products protecting reactive minerals from further reaction. But its effectiveness is decreasing with increasing specific surface area of the reactive minerals in aggregates. - Highlights: • Aluminum of SCM slows down SiO{sub 2} dissolution. • Aluminum of SCM does not alter morphology and structure of ASR product. • ASR suppressing effect of LiNO{sub 3} depends on specific surface area of the aggregates.

  16. Chemolithotrophic Primary Production in a Subglacial Ecosystem

    PubMed Central

    Hamilton, Trinity L.; Havig, Jeff R.; Skidmore, Mark L.; Shock, Everett L.

    2014-01-01

    Glacial comminution of bedrock generates fresh mineral surfaces capable of sustaining chemotrophic microbial communities under the dark conditions that pervade subglacial habitats. Geochemical and isotopic evidence suggests that pyrite oxidation is a dominant weathering process generating protons that drive mineral dissolution in many subglacial systems. Here, we provide evidence correlating pyrite oxidation with chemosynthetic primary productivity and carbonate dissolution in subglacial sediments sampled from Robertson Glacier (RG), Alberta, Canada. Quantification and sequencing of ribulose-1,5-bisphosphate carboxylase/oxygenase (RuBisCO) transcripts suggest that populations closely affiliated with Sideroxydans lithotrophicus, an iron sulfide-oxidizing autotrophic bacterium, are abundant constituents of microbial communities at RG. Microcosm experiments indicate sulfate production during biological assimilation of radiolabeled bicarbonate. Geochemical analyses of subglacial meltwater indicate that increases in sulfate levels are associated with increased calcite and dolomite dissolution. Collectively, these data suggest a role for biological pyrite oxidation in driving primary productivity and mineral dissolution in a subglacial environment and provide the first rate estimate for bicarbonate assimilation in these ecosystems. Evidence for lithotrophic primary production in this contemporary subglacial environment provides a plausible mechanism to explain how subglacial communities could be sustained in near-isolation from the atmosphere during glacial-interglacial cycles. PMID:25085483

  17. PRIMARY PRODUCTION ESTIMATES IN CHESAPEAKE BAY USING SEAWIFS

    EPA Science Inventory

    The temporal and spatial variability in primary production along the main stem of Chesapeake Bay was examined from 1997 through 2000. Primary production estimates were determined from the Vertically Generalized Production Model (VGPM) (Behrenfeld and Falkowski, 1997) using chloro...

  18. Observations of Ocean Primary Productivity Using MODIS

    NASA Technical Reports Server (NTRS)

    Esaias, Wayne E.; Abbott, Mark R.; Koblinsky, Chester J. (Technical Monitor)

    2001-01-01

    Measuring the magnitude and variability of oceanic net primary productivity (NPP) represents a key advancement toward our understanding of the dynamics of marine ecosystems and the role of the ocean in the global carbon cycle. MODIS observations make two new contributions in addition to continuing the bio-optical time series begun with Orbview-2's SeaWiFS sensor. First, MODIS provides weekly estimates of global ocean net primary productivity on weekly and annual time periods, and annual empirical estimates of carbon export production. Second, MODIS provides additional insight into the spatial and temporal variations in photosynthetic efficiency through the direct measurements of solar-stimulated chlorophyll fluorescence. The two different weekly productivity indexes (first developed by Behrenfeld & Falkowski and by Yoder, Ryan and Howard) are used to derive daily productivity as a function of chlorophyll biomass, incident daily surface irradiance, temperature, euphotic depth, and mixed layer depth. Comparisons between these two estimates using both SeaWiFS and MODIS data show significant model differences in spatial distribution after allowance for the different integration depths. Both estimates are strongly dependence on the accuracy of the chlorophyll determination. In addition, an empirical approach is taken on annual scales to estimate global NPP and export production. Estimates of solar stimulated fluorescence efficiency from chlorophyll have been shown to be inversely related to photosynthetic efficiency by Abbott and co-workers. MODIS provides the first global estimates of oceanic chlorophyll fluorescence, providing an important proof of concept. MODIS observations are revealing spatial patterns of fluorescence efficiency which show expected variations with phytoplankton photo-physiological parameters as measured during in-situ surveys. This has opened the way for research into utilizing this information to improve our understanding of oceanic NPP

  19. Lipid Peroxidation Is an Early Symptom Triggered by Aluminum, But Not the Primary Cause of Elongation Inhibition in Pea Roots1

    PubMed Central

    Yamamoto, Yoko; Kobayashi, Yukiko; Matsumoto, Hideaki

    2001-01-01

    Pea (Pisum sativum) roots were treated with aluminum in a calcium solution, and lipid peroxidation was investigated histochemically and biochemically, as well as other events caused by aluminum exposure. Histochemical stainings were observed to distribute similarly on the entire surface of the root apex for three events (aluminum accumulation, lipid peroxidation, and callose production), but the loss of plasma membrane integrity (detected by Evans blue uptake) was localized exclusively at the periphery of the cracks on the surface of root apex. The enhancement of four events (aluminum accumulation, lipid peroxidation, callose production, and root elongation inhibition) displayed similar aluminum dose dependencies and occurred by 4 h. The loss of membrane integrity, however, was enhanced at lower aluminum concentrations and after longer aluminum exposure (8 h). The addition of butylated hydroxyanisole (a lipophilic antioxidant) during aluminum treatment completely prevented lipid peroxidation and callose production by 40%, but did not prevent or slow the other events. Thus lipid peroxidation is a relatively early symptom induced by the accumulation of aluminum and appears to cause, in part, callose production, but not the root elongation inhibition; by comparison, the loss of plasma membrane integrity is a relatively late symptom caused by cracks in the root due to the inhibition of root elongation. PMID:11154329

  20. The productivity of primary care research networks.

    PubMed Central

    Griffiths, F; Wild, A; Harvey, J; Fenton, E

    2000-01-01

    Primary care research networks are being publicly funded in the United Kingdom to promote a culture of research and development in primary care. This paper discusses the organisational form of these networks and how their productivity can be evaluated, drawing on evidence from management science. An evaluation of a research network has to take account of the complexity of the organisation, the influence of its local context, and its stage of development. Output measures, such as number of research papers, and process measures, such as number of research meetings, may contribute to an evaluation. However, as networking relies on the development of informal, trust-based relationships, the quality of interactions within a network is of paramount importance for its success. Networks can audit and reflect on their success in promoting such relationships and a more formal qualitative evaluation by an independent observer can document their success to those responsible for funding. PMID:11141879

  1. The productivity of primary care research networks.

    PubMed

    Griffiths, F; Wild, A; Harvey, J; Fenton, E

    2000-11-01

    Primary care research networks are being publicly funded in the United Kingdom to promote a culture of research and development in primary care. This paper discusses the organisational form of these networks and how their productivity can be evaluated, drawing on evidence from management science. An evaluation of a research network has to take account of the complexity of the organisation, the influence of its local context, and its stage of development. Output measures, such as number of research papers, and process measures, such as number of research meetings, may contribute to an evaluation. However, as networking relies on the development of informal, trust-based relationships, the quality of interactions within a network is of paramount importance for its success. Networks can audit and reflect on their success in promoting such relationships and a more formal qualitative evaluation by an independent observer can document their success to those responsible for funding. PMID:11141879

  2. MODIS-Derived Terrestrial Primary Production

    NASA Astrophysics Data System (ADS)

    Zhao, Maosheng; Running, Steven; Heinsch, Faith Ann; Nemani, Ramakrishna

    Temporal and spatial changes in terrestrial biological productivity have a large impact on humankind because terrestrial ecosystems not only create environments suitable for human habitation, but also provide materials essential for survival, such as food, fiber and fuel. A recent study estimated that consumption of terrestrial net primary production (NPP; a list of all the acronyms is available in the appendix at the end of the chapter) by the human population accounts for about 14-26% of global NPP (Imhoff et al. 2004). Rapid global climate change is induced by increased atmospheric greenhouse gas concentration, especially CO2, which results from human activities such as fossil fuel combustion and deforestation. This directly impacts terrestrial NPP, which continues to change in both space and time (Melillo et al. 1993; Prentice et al. 2001; Nemani et al. 2003), and ultimately impacts the well-being of human society (Milesi et al. 2005). Additionally, substantial evidence show that the oceans and the biosphere, especially terrestrial ecosystems, currently play a major role in reducing the rate of the atmospheric CO2 increase (Prentice et al. 2001; Schimel et al. 2001). NPP is the first step needed to quantify the amount of atmospheric carbon fixed by plants and accumulated as biomass. Continuous and accurate measurements of terrestrial NPP at the global scale are possible using satellite data. Since early 2000, for the first time, the MODIS sensors onboard the Terra and Aqua satellites, have operationally provided scientists with near real-time global terrestrial gross primary production (GPP) and net photosynthesis (PsnNet) data. These data are provided at 1 km spatial resolution and an 8-day interval, and annual NPP covers 109,782,756 km2 of vegetated land. These GPP, PsnNet and NPP products are collectively known as MOD17 and are part of a larger suite of MODIS land products (Justice et al. 2002), one of the core Earth System or Climate Data Records (ESDR or

  3. Production of aluminum-lithium near net shape extruded cylinders

    NASA Technical Reports Server (NTRS)

    Hartley, Paula J.

    1995-01-01

    In the late 1980's, under funding from the Advanced Launch System Program, numerous near net shape technologies were investigated as a means for producing high quality, low cost Aluminum-Lithium (Al-Li) hardware. Once such option was to extrude near net shape barrel panels instead of producing panels by machining thick plate into a final tee-stiffened configuration (which produced up to 90% scrap). This method offers a reduction in the volume of scrap and consequently reduces the buy-to-fly cost. Investigation into this technology continued under Shuttle-C funding where four Al alloys 2219, 2195, 2096, and RX 818 were extruded. Presented herein are the results of that program. Each alloy was successfully extruded at Wyman Gordon, opened and flattened at Ticorm, and solution heat treated and stretched at Reynolds Metals Company. The first two processes were quite successful while the stretching process did offer some challenges. Due to the configuration of the panels and the stretch press set-up, it was difficult to induce a consistent percentage of cold work throughout the length and width of each panel. The effects of this variation will be assessed in the test program to be conducted at a future date.

  4. "A L C L A D" A New Corrosion Resistant Aluminum Product

    NASA Technical Reports Server (NTRS)

    Dix, E H , Jr

    1927-01-01

    Described here is a new corrosion resistant aluminum product which is markedly superior to the present strong alloys. Its use should result in greatly increased life of a structural part. Alclad is a heat-treated aluminum, copper, manganese, magnesium alloy that has the corrosion resistance of pure metal at the surface and the strength of the strong alloy underneath. Of particular importance is the thorough character of the union between the alloy and the pure aluminum. Preliminary results of salt spray tests (24 weeks of exposure) show changes in tensile strength and elongation of Alclad 17ST, when any occurred, to be so small as to be well within the limits of experimental error. Some surface corrosion of the pure metal had taken place, but not enough to cause the specimens to break through those areas.

  5. Case study of polychlorinated naphthalene emissions and factors influencing emission variations in secondary aluminum production.

    PubMed

    Jiang, Xiaoxu; Liu, Guorui; Wang, Mei; Liu, Wenbin; Tang, Chen; Li, Li; Zheng, Minghui

    2015-04-01

    Secondary aluminum production has been recognized as an important source of polychlorinated naphthalenes (PCNs). Large variations in PCN emissions as the smelting process proceeds have not been determined. In this study, solid and gaseous discharges, including fly ash, slag, and stack gas samples collected from four secondary smelting plants during different smelting stages were analyzed for PCNs. The average emission factor of ∑(1-8)PCNs to air was calculated to be 17.4 mg t(-1), with a range of 4.3-29.5 mg t(-1). The average emission factors of ∑(1-8)PCNs from fly ash and slag were 55.5 ng t(-1) and 0.13 ng t(-1), respectively. The derived emission factors may enable a more accurate estimation of annual emissions and a more comprehensive knowledge of the distribution of PCNs emitted from secondary aluminum production. The emission levels and characteristics of PCNs during different smelting stages were compared. Possible factors, including the organic impurities from aluminum scrap, fuel, and chloride additives, which could contribute to variations in PCN emissions and characteristics were discussed. These results may provide useful information for developing better control strategies for reducing PCN emissions in secondary aluminum production.

  6. Target designs for Accelerator Production of Tritium (APT) utilizing lithium-aluminum

    SciTech Connect

    Todosow, M.; Van Tuyle, G.J.

    1996-03-01

    A number of accelerator-driven spallation neutron-source target/blanket systems have been developed for production of tritium under the APT Program. The two systems described in this paper employ a proton linear accelerator, and a target which contains a heavy-metal(s) for the production of neutrons via spallation, and solid lithium-aluminum for the production of tritium via neutron capture. lie lithium-aluminum technology is based on that employed at Savannah River for tritium production since the 1950`s. In the APT concept tritium is produced without the presence of fissionable materials; therefore, no high-level waste is produced, and the ES&H concerns are significantly reduced compared to reactor systems.

  7. Evaluation of borated aluminum products for criticality control in 235-F

    SciTech Connect

    Crouch, W.

    2003-04-01

    Plutonium-containing materials are destined for storage in the 235-F vault. The projected amount of stored materials will require the presence of neutron absorber materials. The leading design concept is for the neutron absorber materials to be in non-load-bearing borated aluminum plates lining the walls of the vault. A comprehensive evaluation of the borated aluminum plate materials was performed to identify a suitable material, and verify that these materials would remain effective as neutron absorbers under normal service conditions and for design-basis events, including the fire accident scenario, throughout a 20-year service life. Aluminum 1100 with boron additions is the recommended neutron absorber material for plutonium material storage in the 235-F vault based on boron loading capacity and durability in the storage environment. Borated aluminum 1100 is commercially available up to 4.5 wt. % boron. A detailed comparison was made of the physical, mechanical, and corrosion properties of borated aluminum alloy 1100 to standard alloy 1100-O1 to demonstrate near-equivalency in properties and to justify application of alloy 1100-O properties to the borated product as needed for the degradation analysis. The expected degradation of the borated aluminum is extremely low for storage conditions, including the bounding scenario of an aggressive atmospheric condition. A maximum loss of 0.00029 inches/year would be expected under potentially aggressive atmospheric conditions and would result in a fractional loss of only 0.42 wt. % of the boron present in a 7mm plate for a 20-year storage period. The fraction of Boron-10 consumption by spontaneous neutrons is expected to be less than 10-8 for the 20-year storage in 235-F fully loaded with Pu materials. The borated aluminum alloy 1100 will be thermally stable and unaltered up to near-melt temperature (643°C). Mechanical testing data at elevated temperatures show that the strengths (yield and ultimate) of the borated

  8. Evaluation of borated aluminum products for criticality control in 235-F

    SciTech Connect

    Duncan, A.; Sindelar, R.

    2003-05-06

    Plutonium-containing materials are destined for storage in the 235-F vault. The projected amount of stored materials will require the presence of neutron absorber materials. The leading design concept is for the neutron absorber materials to be in non-load-bearing borated aluminum plates lining the walls of the vault. A comprehensive evaluation of the borated aluminum plate materials was performed to identify a suitable material, and verify that these materials would remain effective as neutron absorbers under normal service conditions and for design-basis events, including the fire accident scenario, throughout a 20-year service life. Aluminum 1100 with boron additions is the recommended neutron absorber material for plutonium material storage in the 235-F vault based on boron loading capacity and durability in the storage environment. Borated aluminum 1100 is commercially available up to 4.5 wt. % boron. A detailed comparison was made of the physical, mechanical, and corrosion properties of borated aluminum alloy 1100 to standard alloy 1100-O (-O designating the fully annealed condition) to demonstrate near-equivalency in properties and to justify application of alloy 1100-O properties to the borated product as needed for the degradation analysis. The expected degradation of the borated aluminum is extremely low for storage conditions, including the bounding scenario of an aggressive atmospheric condition. A maximum loss of 0.00029 inches/year would be expected under potentially aggressive atmospheric conditions and would result in a fractional loss of only 0.42 wt.% of the boron present in a 7mm plate for a 20-year storage period. The fraction of Boron-10 consumption by spontaneous neutrons is expected to be less than 10{sup -8} for the 20-year storage in 235-F fully loaded with Pu materials. The borated aluminum alloy 1100 will be thermally stable and unaltered up to near-melt temperature (643°C). Mechanical testing data at elevated temperatures show that the

  9. Method And Reactor For Production Of Aluminum By Carbothermic Reduction Of Alumina

    DOEpatents

    Aune, Jan Arthur; Johansen, Kai

    2004-10-19

    A hollow partition wall is employed to feed carbon material to an underflow of a carbothermic reduction furnace used to make aluminum. The partition wall divides a low temperature reaction zone where aluminum oxide is reacted with carbon to form aluminum carbide and a high temperature reaction zone where the aluminum carbide and remaining aluminum oxide are reacted to form aluminum and carbon monoxide.

  10. MODIS Ocean Primary Productivity: Data Products and Services

    NASA Astrophysics Data System (ADS)

    Turpie, K. R.; Esaias, W. E.

    2001-05-01

    Ocean primary production (OPP) is defined as the rate of inorganic carbon uptake into the ocean biosphere, minus respiration. Biological processes can remove carbon from the ocean reservoir, providing an important potential sink for atmospheric carbon. This carbon flux into the ocean biosphere constitutes the base of the pelagic marine food web, directly affecting fishery productivity. Weekly indices of ocean primary production are being generated at Goddard Space Flight Center (GSFC) using semi-analytic and statistical models and remote sensing from the MODIS instrument. The Behrenfeld and Falkowski model is used to provide an estimate of OPP over the full euphotic zone and the Howard, Yoder and Ryan model is used to estimate production in the upper mixed layer. These global data products are produced at resolutions of 4.6 km, 36 km, and 1 degree, and are available to the public through the GSFC Distributive Active Archive Center (GDAAC). Means for weekly periods, basic statistics, and input parameters are available as mapped images and binned files. In addition, limited access and visualization capability of these products are available at the OPP Science Computing Facility (OPP/SCF) website at http://opp.gsfc.nasa.gov. Annual estimates of OPP generated by empirical algorithms will be available after the first year of data is processed. Research products providing similar information generated with SeaWiFS data will also be made available in the near future. The availability of these various products will open new opportunities to deepen our understanding the biological health of our oceans and the role of the ocean biosphere in the carbon cycle.

  11. [Practical Use Evaluation of Aluminum Packaging for Medicinal Products Based on Universal Design].

    PubMed

    Ohtani, Kazuya; Hidaka, Takashi; Marubashi, Koichi; Takagi, Hirokazu; Kamimura, Naoki

    2015-01-01

    Many pharmacists have requested optimization of aluminum packaging of medicinal products in terms of usability. To improve operational efficiency of aluminum packaging, we used Universal Design (UD)-based approach, which enables products to be used properly and consistently regardless of users. The UD-pack used in this research is composed of a film that can be easily opened and torn linear. Here, we compared the UD-pack to conventional aluminum packaging by evaluating the practical use of each under the cooperation of 24 pharmacists. Following opening and removal of contents of one sample for both types of packaging, monitors were asked which type was easier to use in each case. Also, monitors were to repeat the opening and removal of contents of five samples in a row, and were asked the same question. Monitors were recorded by digital camera to measure the time required to finish the procedure for five samples in a row. After opening one sample, approximately 83% of monitors preferred the UD-pack, and after opening five samples, all (100%) preferred the UD-pack. Regarding the time required for opening five samples and removing the contents measured by analyzing the recorded video, the UD-pack significantly reduced the time required for all monitors. The average time ratio of the UD-pack to conventional aluminum packaging was approximately 59%, and no significant difference was observed between male and female pharmacists. Our results indicate the UD-pack improves ease of opening and removal of contents and increases efficiency of dispensing in a clinical setting compared with conventional aluminum packaging.

  12. [Practical Use Evaluation of Aluminum Packaging for Medicinal Products Based on Universal Design].

    PubMed

    Ohtani, Kazuya; Hidaka, Takashi; Marubashi, Koichi; Takagi, Hirokazu; Kamimura, Naoki

    2015-01-01

    Many pharmacists have requested optimization of aluminum packaging of medicinal products in terms of usability. To improve operational efficiency of aluminum packaging, we used Universal Design (UD)-based approach, which enables products to be used properly and consistently regardless of users. The UD-pack used in this research is composed of a film that can be easily opened and torn linear. Here, we compared the UD-pack to conventional aluminum packaging by evaluating the practical use of each under the cooperation of 24 pharmacists. Following opening and removal of contents of one sample for both types of packaging, monitors were asked which type was easier to use in each case. Also, monitors were to repeat the opening and removal of contents of five samples in a row, and were asked the same question. Monitors were recorded by digital camera to measure the time required to finish the procedure for five samples in a row. After opening one sample, approximately 83% of monitors preferred the UD-pack, and after opening five samples, all (100%) preferred the UD-pack. Regarding the time required for opening five samples and removing the contents measured by analyzing the recorded video, the UD-pack significantly reduced the time required for all monitors. The average time ratio of the UD-pack to conventional aluminum packaging was approximately 59%, and no significant difference was observed between male and female pharmacists. Our results indicate the UD-pack improves ease of opening and removal of contents and increases efficiency of dispensing in a clinical setting compared with conventional aluminum packaging. PMID:26632152

  13. Herbivory and Stoichiometric Feedbacks to Primary Production.

    PubMed

    Krumins, Jennifer Adams; Krumins, Valdis; Forgoston, Eric; Billings, Lora; van der Putten, Wim H

    2015-01-01

    Established theory addresses the idea that herbivory can have positive feedbacks on nutrient flow to plants. Positive feedbacks likely emerge from a greater availability of organic carbon that primes the soil by supporting nutrient turnover through consumer and especially microbially-mediated metabolism in the detrital pool. We developed an entirely novel stoichiometric model that demonstrates the mechanism of a positive feedback. In particular, we show that sloppy or partial feeding by herbivores increases detrital carbon and nitrogen allowing for greater nitrogen mineralization and nutritive feedback to plants. The model consists of differential equations coupling flows among pools of: plants, herbivores, detrital carbon and nitrogen, and inorganic nitrogen. We test the effects of different levels of herbivore grazing completion and of the stoichiometric quality (carbon to nitrogen ratio, C:N) of the host plant. Our model analyses show that partial feeding and plant C:N interact because when herbivores are sloppy and plant biomass is diverted to the detrital pool, more mineral nitrogen is available to plants because of the stoichiometric difference between the organisms in the detrital pool and the herbivore. This model helps to identify how herbivory may feedback positively on primary production, and it mechanistically connects direct and indirect feedbacks from soil to plant production.

  14. Herbivory and Stoichiometric Feedbacks to Primary Production.

    PubMed

    Krumins, Jennifer Adams; Krumins, Valdis; Forgoston, Eric; Billings, Lora; van der Putten, Wim H

    2015-01-01

    Established theory addresses the idea that herbivory can have positive feedbacks on nutrient flow to plants. Positive feedbacks likely emerge from a greater availability of organic carbon that primes the soil by supporting nutrient turnover through consumer and especially microbially-mediated metabolism in the detrital pool. We developed an entirely novel stoichiometric model that demonstrates the mechanism of a positive feedback. In particular, we show that sloppy or partial feeding by herbivores increases detrital carbon and nitrogen allowing for greater nitrogen mineralization and nutritive feedback to plants. The model consists of differential equations coupling flows among pools of: plants, herbivores, detrital carbon and nitrogen, and inorganic nitrogen. We test the effects of different levels of herbivore grazing completion and of the stoichiometric quality (carbon to nitrogen ratio, C:N) of the host plant. Our model analyses show that partial feeding and plant C:N interact because when herbivores are sloppy and plant biomass is diverted to the detrital pool, more mineral nitrogen is available to plants because of the stoichiometric difference between the organisms in the detrital pool and the herbivore. This model helps to identify how herbivory may feedback positively on primary production, and it mechanistically connects direct and indirect feedbacks from soil to plant production. PMID:26098841

  15. The History and Future Challenges of Calcined Petroleum Coke Production and Use in Aluminum Smelting

    NASA Astrophysics Data System (ADS)

    Edwards, Les

    2015-02-01

    Calcined petroleum coke is used for the production of carbon anodes in the Hall-Héroult aluminum smelting process due to a combination of low impurity levels, ready availability, and relatively low cost. This article provides a review of the history and use of calcined petroleum coke for anode production and describes the different calcining technologies used by the industry. The article discusses the impact of changes in crude oil quality and refining economics over the last 10 years as well as the impact on green petroleum coke quality and availability. The industry has adapted well to quality changes in recent times, and the blending of different quality cokes by smelters is becoming increasingly important. The world has a plentiful supply of green petroleum coke, but the next wave of aluminum smelting capacity growth will put further pressure on the supply of the higher quality cokes traditionally favored by the industry.

  16. Biogeochemistry of Primary Production in the Sea

    NASA Astrophysics Data System (ADS)

    Falkowski, P. G.

    2003-12-01

    Earth is the only planet in our solar system that contains vast amounts of liquid water on its surface and high concentrations of free molecular oxygen in its atmosphere. These two features are not coincidental. All of the original oxygen on Earth arose from the photobiologically catalyzed splitting of water by unicellular photosynthetic organisms that have inhabited the oceans for at least 3 Gyr. Over that period, these organisms have used the hydrogen atoms from water and other substrates to form organic matter from CO2 and its hydrated equivalents. This process, the de novo formation of organic matter from inorganic carbon, or primary production, is the basis for all life on Earth. In this chapter, we examine the evolution and biogeochemical consequences of primary production in the sea and its relationship to other biogeochemical cycles on Earth.8.05.1.1. The Two Carbon CyclesThere are two major carbon cycles on Earth. The two cycles operate in parallel. One cycle is slow and abiotic. Its effects are observed on multimillion-year timescales and are dictated by tectonics and weathering (Berner, 1990). In this cycle, CO2 is released from the mantle to the atmosphere and oceans via vulcanism and seafloor spreading, and removed from the atmosphere and ocean primarily by reaction with silicates to form carbonates in the latter reservoir. Most of the carbonates are subsequently subducted into the mantle, where they are heated, and their carbon is released as CO2 to the atmosphere and ocean, to carry out the cycle again. The chemistry of this cycle is dependent on acid-base reactions, and would operate whether or not there was life on the planet (Kasting et al., 1988). This slow carbon cycle is a critical determinate of the concentration of CO2 in Earth's atmosphere and oceans on timescales of tens and hundreds of millions of years (Kasting, 1993).The second carbon cycle is dependent on the biologically catalyzed reduction of inorganic carbon to form organic matter

  17. Phosphorous and aluminum gettering in Silicon-Film{trademark} Product II material

    SciTech Connect

    Cotter, J.E.; Barnett, A.M.; Hall, R.B.

    1995-08-01

    Gettering processes are being developed for the Silicon-Film{trademark} Product II solar cell structure. These processes have been developed specifically for films of silicon grown on dissimilar substrates with barrier layers. Gettering with both phosphorous- and aluminum-based processing sequences has resulted in enhancement of minority carrier diffusion length. Long diffusion lengths have allowed the characterization of light trapping in thin films of silicon grown on barrier-coated substrates.

  18. The hydrolytic products of aluminum and their biological significance.

    PubMed

    Bertsch, P M

    1990-03-01

    The relative distribution of Al between its various organic and inorganic complexes dictates its mobility in the environment, bioavailability, and toxicity. In recent years, there has been significant progress made in understanding the differential bioavailability and toxicity of various chemical species of Al to plants and certain aquatic organisms. Far less information concerning chemical speciation and differential uptake and transport of Al in humans is available. Among the important inorganic complexes of interest are the hydrolyzed-Al species, particularly the nonequilibrium, metastable polynuclear complexes, which form readily, have a fairly wide stability range, and have been demonstrated toxic to plants and fish. In recent years(27)Al NMR spectroscopy has provided significant direct information on the polynuclear complexes existing in a wide range of aqueous solutions. The [Al12O4(OH)24+n(H2O)12-n]((7-n)+) polynuclear complex is often found to be the predominant species in partially neutralized Al solutions and has recently been demonstrated to be more toxic to certain plants than the hexaaqua Al cation. It is also the principal component of Al-chlorohydrate, a highly soluble antiperspirant, present in many hydrolyzed Al solutions utilized in water and waste water treatment, and, as hypothesized herein, a primary constituent of many hydroxide gels utilized as antacids. This polynuclear has a wide pH stability range, reportedly forms copolynuclears with Si, and contains tetrahedrally coordinated Al within its structure, all features that may be relevant to the recently reported properties of Al associated with neuritic plaque cores.

  19. 40 CFR Table F-1 to Subpart F of... - Slope and Overvoltage Coefficients for the Calculation of PFC Emissions From Aluminum Production

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... the Calculation of PFC Emissions From Aluminum Production F Table F-1 to Subpart F of Part 98... GREENHOUSE GAS REPORTING Aluminum Production Pt. 98, Subpt. F, Table F-1 Table F-1 to Subpart F of Part 98—Slope and Overvoltage Coefficients for the Calculation of PFC Emissions From Aluminum...

  20. 40 CFR Table F-1 to Subpart F of... - Slope and Overvoltage Coefficients for the Calculation of PFC Emissions From Aluminum Production

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... the Calculation of PFC Emissions From Aluminum Production F Table F-1 to Subpart F of Part 98... GREENHOUSE GAS REPORTING Aluminum Production Pt. 98, Subpt. F, Table F-1 Table F-1 to Subpart F of Part 98—Slope and Overvoltage Coefficients for the Calculation of PFC Emissions From Aluminum...

  1. 40 CFR Table F-1 to Subpart F of... - Slope and Overvoltage Coefficients for the Calculation of PFC Emissions From Aluminum Production

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... the Calculation of PFC Emissions From Aluminum Production F Table F-1 to Subpart F of Part 98... GREENHOUSE GAS REPORTING Aluminum Production Pt. 98, Subpt. F, Table F-1 Table F-1 to Subpart F of Part 98—Slope and Overvoltage Coefficients for the Calculation of PFC Emissions From Aluminum...

  2. 40 CFR Table F-1 to Subpart F of... - Slope and Overvoltage Coefficients for the Calculation of PFC Emissions From Aluminum Production

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... the Calculation of PFC Emissions From Aluminum Production F Table F-1 to Subpart F of Part 98... GREENHOUSE GAS REPORTING Aluminum Production Pt. 98, Subpt. F, Table F-1 Table F-1 to Subpart F of Part 98—Slope and Overvoltage Coefficients for the Calculation of PFC Emissions From Aluminum...

  3. Development of a Novel Non-Consumable Anode for Electrowinning Primary Aluminum

    SciTech Connect

    Robert A. Rapp; Y. Zhang

    2003-12-04

    The principal goal of the project was to determine through theoretical considerations and from chemical and electrochemical laboratory studies the technical and economic feasibility for the substitution and retrofitting of an SOFC-type anode for today's carbon anode in a cell for electrowinning primary Al. However, solubility measurements showed that no value of cryolite ratio can exist where the solubilities of the solid electrolyte components (zirconia and especially yttria) would be small relative to the alumina solubility. Therefore, the utilization of the proposed SOFC-type anode cannot be realized for any cell involving a cryolite-base solvent. However, the project suggested that the SOFC-type anode scheme might be successful if the solvent/electrolyte for electrowinning Al could be changed to a fused sulfate melt. During the solubility experiments, electrochemical probes were developed, and a bath characterization was defined, to measure quantitatively the acid-base character of cryolite melts. The measured acid-base behavior was then used to correlate the alumina solubility in cryolite over a wide range of cryolite ratio at 1300K. A mathematical modeling of the alumina solubility as a function of basicity identified three solutes of Al{sub 2}O{sub 3} in cryolite-base melts: Na{sub 2}Al{sub 2}OF{sub 6}, Na{sub 2}Al{sub 2}O{sub 2}F{sub 4}, and Na{sub 4}Al{sub 2}O{sub 2}F{sub 6} as acidic, neutral and basic solutes, respectively. For the first time, the stereochemistry (geometries) of these complex solutes was clarified. For the non-oxygen containing Al-F complex anions, Na{sub 3}AlF{sub 6} and NaAlF{sub 4} were also considered as solutes, and some NaF (but no AlF{sub 3}) could remain in the melts. The previously suggested solute Na{sub 2}AlF{sub 5} was found to be unstable. The strong complexing in the cryolite/alumina system means that the bath is highly buffered so that a significant shift in basicity is not possible and therefore the alumina solubility

  4. Occupational exposure to aluminum and its biomonitoring in perspective.

    PubMed

    Riihimäki, Vesa; Aitio, Antero

    2012-11-01

    Exposure to aluminum at work is widespread, and people are exposed to several species of aluminum, which differ markedly as to the kinetics and toxicity. Especially welding of aluminum is widely applied and continuously expanding. Inhalation of fine particles of sparsely soluble aluminum results in the retention of deposited particles in the lungs. From the lungs, aluminum is released to the blood and distributed to bones and the brain, and excreted to urine. Soluble aluminum compounds are not accumulated in the lungs. Neurotoxicity is the critical effect of exposure to sparsely soluble aluminum compounds. Studies on workers exposed to aluminum welding fumes have revealed disturbances of cognitive processes, memory and concentration, and changes in mood and EEG. Early pulmonary effects have been observed among aluminum powder-production workers using high-resolution computed tomography. The primary objective of aluminum biomonitoring (BM) is to help prevent the formation of aluminum burden in the lungs and thereby to prevent harmful accumulation of aluminum in target organs. BM of aluminum can be effectively used for this purpose in the production/use of aluminum powders, aluminum welding, as well as plasma cutting, grinding, polishing and thermal spraying of aluminum. BM of aluminum may also be similarly useful in the smelting of aluminum and probably in the production of corundum. BM can help identify exposed individuals and roughly quantitate transient exposure but cannot predict health effects in the production/use of soluble aluminum salts. For urinary aluminum (U-Al) we propose an action limit of 3 µmol/L, corrected to a relative density of 1.021, in a sample collected preshift after two days without occupational exposure, and without use of aluminum-containing drugs. This value corresponds roughly to 2.3 µmol/g creatinine. Compliance with this limit is expected to protect the worker against the critical effect of aluminum in exposure to sparsely soluble

  5. Global patterns in human consumption of net primary production

    NASA Astrophysics Data System (ADS)

    Imhoff, Marc L.; Bounoua, Lahouari; Ricketts, Taylor; Loucks, Colby; Harriss, Robert; Lawrence, William T.

    2004-06-01

    The human population and its consumption profoundly affect the Earth's ecosystems. A particularly compelling measure of humanity's cumulative impact is the fraction of the planet's net primary production that we appropriate for our own use. Net primary production-the net amount of solar energy converted to plant organic matter through photosynthesis-can be measured in units of elemental carbon and represents the primary food energy source for the world's ecosystems. Human appropriation of net primary production, apart from leaving less for other species to use, alters the composition of the atmosphere, levels of biodiversity, energy flows within food webs and the provision of important ecosystem services. Here we present a global map showing the amount of net primary production required by humans and compare it to the total amount generated on the landscape. We then derive a spatial balance sheet of net primary production `supply' and `demand' for the world. We show that human appropriation of net primary production varies spatially from almost zero to many times the local primary production. These analyses reveal the uneven footprint of human consumption and related environmental impacts, indicate the degree to which human populations depend on net primary production `imports' and suggest policy options for slowing future growth of human appropriation of net primary production.

  6. Global patterns in human consumption of net primary production.

    PubMed

    Imhoff, Marc L; Bounoua, Lahouari; Ricketts, Taylor; Loucks, Colby; Harriss, Robert; Lawrence, William T

    2004-06-24

    The human population and its consumption profoundly affect the Earth's ecosystems. A particularly compelling measure of humanity's cumulative impact is the fraction of the planet's net primary production that we appropriate for our own use. Net primary production--the net amount of solar energy converted to plant organic matter through photosynthesis--can be measured in units of elemental carbon and represents the primary food energy source for the world's ecosystems. Human appropriation of net primary production, apart from leaving less for other species to use, alters the composition of the atmosphere, levels of biodiversity, energy flows within food webs and the provision of important ecosystem services. Here we present a global map showing the amount of net primary production required by humans and compare it to the total amount generated on the landscape. We then derive a spatial balance sheet of net primary production 'supply' and 'demand' for the world. We show that human appropriation of net primary production varies spatially from almost zero to many times the local primary production. These analyses reveal the uneven footprint of human consumption and related environmental impacts, indicate the degree to which human populations depend on net primary production 'imports' and suggest policy options for slowing future growth of human appropriation of net primary production.

  7. Global Patterns in Human Consumption of Net Primary Production

    NASA Technical Reports Server (NTRS)

    Imhoff, Marc L.; Bounoua, Lahouari; Ricketts, Taylor; Loucks, Colby; Harriss, Robert; Lawrence William T.

    2004-01-01

    The human population and its consumption profoundly affect the Earth's ecosystems. A particularly compelling measure of humanity's cumulative impact is the fraction of the planet's net primary production that we appropriate for our Net primary production-the net amount of solar energy converted to plant organic matter through photosynthesis-can be measured in units of elemental carbon and represents the primary food energy source for the world's ecosystems. Human appropriation of net primary production, apart from leaving less for other species to use, alters the composition of the atmosphere, levels of biodiversity, flows within food webs and the provision of important primary production required by humans and compare it to the total amount generated on the landscape. We then derive a spatial ba!mce sheet of net primary production supply and demand for the world. We show that human appropriation of net primary production varies spatially from almost zero to many times the local primary production. These analyses reveal the uneven footprint of human consumption and related environmental impacts, indicate the degree to which human populations depend on net primary production "imports" and suggest policy options for slowing future growth of human appropriation of net primary production.

  8. Wear products that form during tribological tests of aluminum-matrix composite materials

    NASA Astrophysics Data System (ADS)

    Kalashnikov, I. E.; Bolotova, L. K.; Kobeleva, L. I.; Bykov, P. A.; Kolmakov, A. G.

    2015-04-01

    The wear products and the friction surfaces of the composite materials fabricated by reactive casting after the addition of commercial-purity aluminum AD1, titanium and nickel powders, and nanosized modifiers to a matrix melt are studied. The dispersity and the chemical composition of the wear products that form an intermediate layer between the contacting surfaces are analyzed, and the dominating wear mechanisms under experimental tribological loading conditions are determined. It is shown that the formation of such a disperse intermediate layer during lubricant-free friction of the synthesized composite materials decreases the temperature in the tribological contact and ensures a transition from weak to intense wear at higher critical loads.

  9. Importance of coastal primary production in the northern Baltic Sea.

    PubMed

    Ask, Jenny; Rowe, Owen; Brugel, Sonia; Strömgren, Mårten; Byström, Pär; Andersson, Agneta

    2016-10-01

    In this study, we measured depth-dependent benthic microalgal primary production in a Bothnian Bay estuary to estimate the benthic contribution to total primary production. In addition, we compiled data on benthic microalgal primary production in the entire Baltic Sea. In the estuary, the benthic habitat contributed 17 % to the total annual primary production, and when upscaling our data to the entire Bothnian Bay, the corresponding value was 31 %. This estimated benthic share (31 %) is three times higher compared to past estimates of 10 %. The main reason for this discrepancy is the lack of data regarding benthic primary production in the northern Baltic Sea, but also that past studies overestimated the importance of pelagic primary production by not correcting for system-specific bathymetric variation. Our study thus highlights the importance of benthic communities for the northern Baltic Sea ecosystem in general and for future management strategies and ecosystem studies in particular. PMID:27075572

  10. The use of aluminum nitride to improve Aluminum-26 Accelerator Mass Spectrometry measurements and production of Radioactive Ion Beams

    NASA Astrophysics Data System (ADS)

    Janzen, Meghan S.; Galindo-Uribarri, Alfredo; Liu, Yuan; Mills, Gerald D.; Romero-Romero, Elisa; Stracener, Daniel W.

    2015-10-01

    We present results and discuss the use of aluminum nitride as a promising source material for Accelerator Mass Spectrometry (AMS) and Radioactive Ion Beams (RIBs) science applications of 26Al isotopes. The measurement of 26Al in geological samples by AMS is typically conducted on Al2O3 targets. However, Al2O3 is not an ideal source material because it does not form a prolific beam of Al- required for measuring low-levels of 26Al. Multiple samples of aluminum oxide (Al2O3), aluminum nitride (AlN), mixed Al2O3-AlN as well as aluminum fluoride (AlF3) were tested and compared using the ion source test facility and the stable ion beam (SIB) injector platform at the 25-MV tandem electrostatic accelerator at Oak Ridge National Laboratory. Negative ion currents of atomic and molecular aluminum were examined for each source material. It was found that pure AlN targets produced substantially higher beam currents than the other materials and that there was some dependence on the exposure of AlN to air. The applicability of using AlN as a source material for geological samples was explored by preparing quartz samples as Al2O3 and converting them to AlN using a carbothermal reduction technique, which involved reducing the Al2O3 with graphite powder at 1600 °C within a nitrogen atmosphere. The quartz material was successfully converted to AlN. Thus far, AlN proves to be a promising source material and could lead towards increasing the sensitivity of low-level 26Al AMS measurements. The potential of using AlN as a source material for nuclear physics is also very promising by placing 26AlN directly into a source to produce more intense radioactive beams of 26Al.

  11. Future materials requirements for the high-energy-intensity production of aluminum

    NASA Astrophysics Data System (ADS)

    Welch, B. J.; Hyland, M. M.; James, B. J.

    2001-02-01

    Like all metallurgical industries, aluminum smelting has been under pressure from two fronts—to give maximum return on investment to the shareholders and to comply with environmental regulations by reducing greenhouse emissions. The smelting process has advanced by improving efficiency and productivity while continuing to seek new ways to extend the cell life. Materials selection (particularly the use of more graphitized cathodic electrodes) has enabled lower energy consumption, while optimization of the process and controlling in a narrow band has enabled increases in productivity and operations at higher current densities. These changes have, in turn, severely stressed the materials used for cell construction, and new problems are emerging that are resulting in a reduction of cell life. The target for aluminum electro-winning has been to develop an oxygen-evolving electrode, rather than one that evolves substantial amounts of carbon dioxide. Such an electrode, when combined with suitable wettable cathode material developments, would reduce operating costs by eliminating the need for frequent electrode change and would enable more productive cell designs and reduce plant size. The materials specifications for developing these are, however, an extreme challenge. Those specifications include minimized corrosion rate of any electrode into the electrolyte, maintaining an electronically conducting oxidized surface that is of low electrical resistance, meeting the metal purity targets, and enabling variable operating current densities. Although the materials specifications can readily be written, the processing and production of the materials is the challenge.

  12. Net primary production of forests: a constant fraction of gross primary production?

    PubMed

    Waring, R. H.; Landsberg, J. J.; Williams, M.

    1998-02-01

    Considerable progress has been made in our ability to model and measure annual gross primary production (GPP) by terrestrial vegetation. But challenges remain in estimating maintenance respiration (R(m)) and net primary production (NPP). To search for possible common relationships, we assembled annual carbon budgets from six evergreen and one deciduous forest in Oregon, USA, three pine plantations in New South Wales, Australia, a deciduous forest in Massachusetts, USA, and a Nothofagus forest on the South Island of New Zealand. At all 12 sites, a standard procedure was followed to estimate annual NPP of foliage, branches, stems, and roots, the carbon expended in synthesis of these organs (R(g)), their R(m), and that of previously produced foliage and sapwood in boles, branches, and large roots. In the survey, total NPP ranged from 120 to 1660 g C m(-2) year(-1), whereas the calculated fraction allocated to roots varied from 0.22 to 0.63. Comparative analysis indicated that the total NPP/GPP ratio was conservative (0.47 +/- 0.04 SD). This finding supports the possibility of greatly simplifying forest growth models. The constancy of the NPP/GPP ratio also provides an incentive to renew efforts to understand the environmental factors affecting partitioning of NPP above and belowground.

  13. Formation of calcium in the products of iron oxide-aluminum thermite combustion in air

    NASA Astrophysics Data System (ADS)

    Gromov, A. A.; Gromov, A. M.; Popenko, E. M.; Sergienko, A. V.; Sabinskaya, O. G.; Raab, B.; Teipel, U.

    2016-10-01

    The composition of condensed products resulting from the combustion of thermite mixtures (Al + Fe2O3) in air is studied by precise methods. It is shown that during combustion, calcium is formed and stabilized in amounts of maximal 0.55 wt %, while is missing from reactants of 99.7 wt % purity. To explain this, it is hypothesized that a low-energy nuclear reaction takes place alongside the reactions of aluminum oxidation and nitridation, resulting in the formation of calcium (Kervran-Bolotov reaction).

  14. Inert anode containing base metal and noble metal useful for the electrolytic production of aluminum

    DOEpatents

    Ray, Siba P.; Liu, Xinghua

    2000-01-01

    An inert anode for production of metals such as aluminum is disclosed. The inert anode comprises a base metal selected from Cu and Ag, and at least one noble metal selected from Ag, Pd, Pt, Au, Rh, Ru, Ir and Os. The inert anode may optionally be formed of sintered particles having interior portions containing more base metal than noble metal and exterior portions containing more noble metal than base metal. In a preferred embodiment, the base metal comprises Cu, and the noble metal comprises Ag, Pd or a combination thereof.

  15. Production of anhydrous aluminum chloride composition and process for electrolysis thereof

    DOEpatents

    Vandegrift, George F.; Krumpelt, Michael; Horwitz, E. Philip

    1983-01-01

    A process for producing an anhydrous aluminum chloride composition from a water-based aluminous material such as a slurry of aluminum hydroxide in a multistage extraction process in which the aluminum ion is first extracted into an organic liquid containing an acidic extractant and then extracted from the organic phase into an alkali metal chloride or chlorides to form a melt containing a mixture of chlorides of alkali metal and aluminum. In the process, the organic liquid may be recycled. In addition, the process advantageously includes an electrolysis cell for producing metallic aluminum and the alkali metal chloride or chlorides may be recycled for extraction of the aluminum from the organic phase.

  16. Modelling Lake Primary Production Based on Satellite Data

    NASA Astrophysics Data System (ADS)

    Soomets, Tuuli; Kutser, Tiit; Danckaert, Thomas

    2015-12-01

    The productivity of the lakes has a marked importance in the estimation of their ecological state and for predicting their development in the future. Combining modelling with Earth Observation data facilitates a new perspective for lake primary production studies. In this study the primary production was modelled for a 3 different large lakes (Geneva, Peipsi and Võrtsjärv) using MERIS images. We used a semi-empirical model that estimates primary production as a function of photosynthetically absorbed radiation and quantum yield of carbon fixation. The necessary input parameters of the model (concentration of chlorophyll a, downwelling irradiance, and the diffuse attenuation coefficient) were obtained from MERIS products. The primary production maps allow us to study temporal and spatial changes in those lakes.

  17. Cerium-based, intermetallic-strengthened aluminum casting alloy: High-volume co-product development

    DOE PAGESBeta

    Sims, Zachary C.; Weiss, D.; McCall, S. K.; McGuire, M. A.; Ott, R. T.; Geer, Tom; Rios, Orlando; Turchi, P. A. E.

    2016-05-23

    Here, several rare earth elements are considered by-products to rare earth mining efforts. By using one of these by-product elements in a high-volume application such as aluminum casting alloys, the supply of more valuable rare earths can be globally stabilized. Stabilizing the global rare earth market will decrease the long-term criticality of other rare earth elements. The low demand for Ce, the most abundant rare earth, contributes to the instability of rare earth extraction. In this article, we discuss a series of intermetallic-strengthened Al alloys that exhibit the potential for new high-volume use of Ce. The castability, structure, and mechanicalmore » properties of binary, ternary, and quaternary Al-Ce based alloys are discussed. We have determined Al-Ce based alloys to be highly castable across a broad range of compositions. Nanoscale intermetallics dominate the microstructure and are the theorized source of the high ductility. In addition, room-temperature physical properties appear to be competitive with existing aluminum alloys with extended high-temperature stability of the nanostructured intermetallic.« less

  18. Cerium-Based, Intermetallic-Strengthened Aluminum Casting Alloy: High-Volume Co-product Development

    NASA Astrophysics Data System (ADS)

    Sims, Zachary C.; Weiss, D.; McCall, S. K.; McGuire, M. A.; Ott, R. T.; Geer, Tom; Rios, Orlando; Turchi, P. A. E.

    2016-07-01

    Several rare earth elements are considered by-products to rare earth mining efforts. By using one of these by-product elements in a high-volume application such as aluminum casting alloys, the supply of more valuable rare earths can be globally stabilized. Stabilizing the global rare earth market will decrease the long-term criticality of other rare earth elements. The low demand for Ce, the most abundant rare earth, contributes to the instability of rare earth extraction. In this article, we discuss a series of intermetallic-strengthened Al alloys that exhibit the potential for new high-volume use of Ce. The castability, structure, and mechanical properties of binary, ternary, and quaternary Al-Ce based alloys are discussed. We have determined Al-Ce based alloys to be highly castable across a broad range of compositions. Nanoscale intermetallics dominate the microstructure and are the theorized source of the high ductility. In addition, room-temperature physical properties appear to be competitive with existing aluminum alloys with extended high-temperature stability of the nanostructured intermetallic.

  19. Power plants: effects of chlorination on estuarine primary production.

    PubMed

    Hamilton, D H; Flemer, D A; Keefe, C W; Mihursky, J A

    1970-07-10

    Steam electric stations may reduce primary production of cooling water by 91 percent as a result of chlorine applications for control of fouling organisms. Bacterial densities and concentrations of chlorophyll a are also reduced. Slight stimulation of production may occur in the absence of chlorination. Based on the available supply of "new" water, we calculate a maximum loss of primary production of 6.6 percent for the adjacent tidal segment of the Patuxent River. PMID:5427354

  20. Astringent drug products that produce aluminum acetate; skin protectant drug products for over-the-counter human use; technical amendment. Final rule; technical amendment.

    PubMed

    2009-03-01

    We (Food and Drug Administration (FDA)) are amending the final monograph (FM) for over-the-counter (OTC) skin protectant astringent drug products. This amendment clarifies that aluminum acetate solutions, produced by dissolving aluminum sulfate tetradecahydrate and calcium acetate monohydrate in powder or tablet form in water, are generally recognized as safe and effective (GRASE) and not misbranded as astringent drug products. The amendment also describes how manufacturers should relabel these products to comply with the FM. We are issuing this amendment in response to a citizen petition (CP) that we received from a manufacturer of OTC astringent drug products. This final rule is part of our ongoing review of OTC drug products.

  1. Interannual Variation in Phytoplankton Primary Production at a Global Scale

    NASA Technical Reports Server (NTRS)

    Rousseaux, Cecile Severine; Gregg, Watson W.

    2013-01-01

    We used the NASA Ocean Biogeochemical Model (NOBM) combined with remote sensing data via assimilation to evaluate the contribution of four phytoplankton groups to the total primary production. First, we assessed the contribution of each phytoplankton groups to the total primary production at a global scale for the period 1998-2011. Globally, diatoms contributed the most to the total phytoplankton production ((is)approximately 50%, the equivalent of 20 PgC·y1). Coccolithophores and chlorophytes each contributed approximately 20% ((is) approximately 7 PgC·y1) of the total primary production and cyanobacteria represented about 10% ((is) approximately 4 PgC·y1) of the total primary production. Primary production by diatoms was highest in the high latitudes ((is) greater than 40 deg) and in major upwelling systems (Equatorial Pacific and Benguela system). We then assessed interannual variability of this group-specific primary production over the period 1998-2011. Globally the annual relative contribution of each phytoplankton groups to the total primary production varied by maximum 4% (1-2 PgC·y1). We assessed the effects of climate variability on group-specific primary production using global (i.e., Multivariate El Niño Index, MEI) and "regional" climate indices (e.g., Southern Annular Mode (SAM), Pacific Decadal Oscillation (PDO) and North Atlantic Oscillation (NAO)). Most interannual variability occurred in the Equatorial Pacific and was associated with climate variability as indicated by significant correlation (p (is) less than 0.05) between the MEI and the group-specific primary production from all groups except coccolithophores. In the Atlantic, climate variability as indicated by NAO was significantly correlated to the primary production of 2 out of the 4 groups in the North Central Atlantic (diatoms/cyanobacteria) and in the North Atlantic (chlorophytes and coccolithophores). We found that climate variability as indicated by SAM had only a limited effect

  2. Effects of fluorine emission on agricultural products surrounding an aluminum factory

    SciTech Connect

    Muramoto, S.; Nishizaki, H.; Aoyama, I. )

    1991-06-01

    The F concentrations of precipitate dust, agricultural products, and fingernail and hair at the surrounding Al factory were investigated. The F content of dust ranged from 15400 to 42500 micrograms/g dry weight, 190,000 to 380,000 micrograms/g Al. Rice grain contained about 3.4 times more F than that in the control area, but some kinds of agricultural products, egg plants (S. melongena L.), mulberry plants (M. japonica Bailey non Sieb.), and soy beans (G. max (L.) Merrill) were almost equal to that of controls. Also, the high F concentration in the hair and nails of some workers was affected by available F contents in the emission from the factory as well as food and water surrounding the aluminum factory compared with those of control area.

  3. Effects of fluorine emission on agricultural products surrounding an aluminum factory.

    PubMed

    Muramoto, S; Nishizaki, H; Aoyama, I

    1991-06-01

    The F concentrations of precipitate dust, agricultural products, and fingernail and hair at the surrounding Al factory were investigated. The F content of dust ranged from 15400 to 42500 micrograms/g dry weight, 190,000 to 380,000 micrograms/g Al. Rice grain contained about 3.4 times more F than that in the control area, but some kinds of agricultural products, egg plants (S. melongena L.), mulberry plants (M. japonica Bailey non Sieb.), and soy beans (G. max (L.) Merrill) were almost equal to that of controls. Also, the high F concentration in the hair and nails of some workers was affected by available F contents in the emission from the factory as well as food and water surrounding the aluminum factory compared with those of control area.

  4. 76 FR 76259 - National Emissions Standards for Hazardous Air Pollutants: Primary Aluminum Reduction Plants

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-12-06

    ... Equipment Leaks, and Coke By-Product Recovery Plants (Benzene NESHAP) (54 FR 38044, September 14, 1989). The... is no higher than approximately 1-in-10 thousand, that risk level is considered acceptable.'' 54 FR... protect the public health, as required by CAA section 112(f). 54 FR 38046. As discussed in the...

  5. Metals suitable for fluorine gas target bodies: first use of aluminum for the production of [18F]F2.

    PubMed

    Bishop, A; Satyamurthy, N; Bida, G; Phelps, M; Barrio, J R

    1996-04-01

    A comprehensive evaluation of different metals (aluminum, silver, copper, nickel, and gold-plated copper) was undertaken for the fabrication of target bodies with straight and conical bore shapes for the production of [18F]F2 via the 20Ne(d,alpha)18F nuclear reaction. Of these metals, aluminum, silver and copper have never been used for the production of [18F]F2. All these target bodies were easily passivated using a mild beam-induced plasma technique in the presence of 1% F2 in neon or argon. The recovery of 18F activity was higher with electroformed nickel and silver bodies, probably due to favorable thermal conductivities. Aluminum proved to be a useful material for fluorine gas targets. The consistent recovery of 18F activities, ease and low cost of manufacturing and low nuclear activation properties all make aluminum an ideal choice for fluorine gas targetry. To our knowledge, this investigation is the first to highlight the use of aluminum as a target body material for the routine production of [18F]F2. A reasonable mechanism based on the Langmuir-Rideal surface atom recombination is also proposed for the behavior of [18F]F2 recovery from a nickel target body.

  6. Energy Balance Regulation and Flexible Production: A New Frontier for Aluminum Smelting

    NASA Astrophysics Data System (ADS)

    Taylor, Mark P.; Etzion, Ron; Lavoie, Pascal; Tang, Jianning

    2014-12-01

    Through a critical review of recent literature on aluminum smelting cell energy balance, this paper defines specific energy constraints which govern the feasibility of cell operation in practice. Using these constraints as a basis, the objective of reducing energy consumption per kilogram of aluminum produced was examined, again with reference to published data and modern cell developments over the last 5 years. Both incremental and quantum steps in cell design are considered in this analysis, in pursuit of a pathway to lower energy consumption in a process where energy efficiency has not yet risen above 50 pct. In Section V and VI of this work, a generic high amperage cell technology is examined using a computational model of the cell energy balance, in which the resultant electrolyte phases and their thermal, electrical, and physical states can be determined. Using a series of trial energy balances, a feasible operating point emerges, and the possibility of flexible cell amperage and production rate is tested in a preliminary way. The specific energy consumption and market implications of this new technology direction are examined.

  7. Aluminum Exposure in Neonatal Patients Using the Least Contaminated Parenteral Nutrition Solution Products

    PubMed Central

    Poole, Robert L.; Pieroni, Kevin P.; Gaskari, Shabnam; Dixon, Tessa; Kerner, John A.

    2012-01-01

    Aluminum (Al) is a contaminant in all parenteral nutrition (PN) solution component products. Manufacturers currently label these products with the maximum Al content at the time of expiry. We recently published data to establish the actual measured concentration of Al in PN solution products prior to being compounded in the clinical setting [1]. The investigation assessed quantitative Al content of all available products used in the formulation of PN solutions. The objective of this study was to assess the Al exposure in neonatal patients using the least contaminated PN solutions and determine if it is possible to meet the FDA “safe limit” of less than 5 μg/kg/day of Al. The measured concentrations from our previous study were analyzed and the least contaminated products were identified. These concentrations were entered into our PN software and the least possible Al exposure was determined. A significant decrease (41%–44%) in the Al exposure in neonatal patients can be achieved using the least contaminated products, but the FDA “safe limit” of less than 5 μg/kg/day of Al was not met. However, minimizing the Al exposure may decrease the likelihood of developing Al toxicity from PN. PMID:23201834

  8. Primary and bacterial secondary production in a southwestern reservoir

    SciTech Connect

    Chrzanowski, T.H.; Hubbard, J.G.

    1988-03-01

    Rates of primary and bacterial secondary production in Lake Arlington, Texas, were determined. The lake is a warm (annual temperature range, 7 to 32/sup 0/C), shallow, monomictic reservoir with limited macrophyte development in the littoral zone. Samples were collected from six depths within the photic zone from a site located over the deepest portion of the lake. Primary production and bacterial production were calculated from NaH/sup 14/CO/sub 3/ and (methyl-/sup 3/H)thymidine incorporation, respectively. Peak instantaneous production ranged between 14.8 and 220.5 ..mu..g of C liter/sup -1/ h/sup -1/. There were two distinct periods of high rates of production. Growth rates during late fall through spring were typically around 0.002 h/sup -1/, and production rates were typically 5 ..mu..g of C liter/sup -1/ h/sup -1/. Growth rates were higher during warmer parts of the year and reached 0.03 h/sup -1/ by August. The maximum instantaneous rate of bacterial production was approximately 45 ..mu..g of C liter/sup -1/ h/sup -1/. Annual areal bacterial production was 125 g of C m/sup -2/. Temporal and spatial distribution of bacterial numbers and activities coincided with temporal and spatial distributions of primary production. Areal primary and bacterial secondary production were highly correlated.

  9. Technological, Economic, and Environmental Optimization of Aluminum Recycling

    NASA Astrophysics Data System (ADS)

    Ioana, Adrian; Semenescu, Augustin

    2013-08-01

    The four strategic directions (referring to the entire life cycle of aluminum) are as follows: production, primary use, recycling, and reuse. Thus, in this work, the following are analyzed and optimized: reducing greenhouse gas emissions from aluminum production, increasing energy efficiency in aluminum production, maximizing used-product collection, recycling, and reusing. According to the energetic balance at the gaseous environment level, the conductive transfer model is also analyzed through the finished elements method. Several principles of modeling and optimization are presented and analyzed: the principle of analogy, the principle of concepts, and the principle of hierarchization. Based on these principles, an original diagram model is designed together with the corresponding logic diagram. This article also presents and analyzes the main benefits of aluminum recycling and reuse. Recycling and reuse of aluminum have the main advantage that it requires only about 5% of energy consumed to produce it from bauxite. The aluminum recycling and production process causes the emission of pollutants such as dioxides and furans, hydrogen chloride, and particulate matter. To control these emissions, aluminum recyclers are required to comply with the National Emission Standards for Hazardous Air Pollutants for Secondary Aluminum Production. The results of technological, economic, and ecological optimization of aluminum recycling are based on the criteria function's evaluation in the modeling system.

  10. Reduction of Carbon Footprint and Energy Efficiency Improvement in Aluminum Production by Use of Novel Wireless Instrumentation Integrated with Mathematical Modeling

    SciTech Connect

    James W. Evans

    2012-04-11

    The work addressed the greenhouse gas emission and electrical energy consumption of the aluminum industry. The objective was to provide a means for reducing both through the application of wireless instrumentation, coupled to mathematical modeling. Worldwide the aluminum industry consumes more electrical energy than all activities in many major countries (e.g. the UK) and emits more greenhouse gasses (e.g. than France). Most of these excesses are in the 'primary production' of aluminum; that is the conversion of aluminum oxide to metal in large electrolytic cells operating at hundreds of thousands of amps. An industry-specific GHG emission has been the focus of the work. The electrolytic cells periodically, but at irregular intervals, experience an upset condition known as an 'anode effect'. During such anode effects the cells emit fluorinated hydrocarbons (PFCs, which have a high global warming potential) at a rate far greater than in normal operation. Therefore curbing anode effects will reduce GHG emissions. Prior work had indicated that the distribution of electrical current within the cell experiences significant shifts in the minutes before an anode effect. The thrust of the present work was to develop technology that could detect and report this early warning of an anode effect so that the control computer could minimize GHG emissions. A system was developed to achieve this goal and, in collaboration with Alcoa, was tested on two cells at an Alcoa plant in Malaga, Washington. The project has also pointed to the possibility of additional improvements that could result from the work. Notable among these is an improvement in efficiency that could result in an increase in cell output at little extra operating cost. Prospects for commercialization have emerged in the form of purchase orders for further installations. The work has demonstrated that a system for monitoring the current of individual anodes in an aluminum cell is practical. Furthermore the system has

  11. Pechiney Rolled Products: Plant-Wide Energy Assessment Identifies Opportunities to Optimize Aluminum Casting and Rolled Operations

    SciTech Connect

    2004-07-01

    A Pechiney Rolled Products plant focused on various aluminum casting processes during a PWA. The assessment revealed potential annual savings of 460,000 MMBtu in natural gas, 9.6 million kWh in electricity, 69 million pounds in CO2, and $2.5 million.

  12. Pechiney Rolled Products: Plant-Wide Energy Assessment Identifies Opportunities to Optimize Aluminum Casting and Rolling Operations

    SciTech Connect

    Not Available

    2004-07-01

    A Pechiney Rolled Products plant focused on various aluminum casting processes during a PWA. The assessment revealed potential annual savings of 460,000 MMBtu in natural gas, 9.6 million kWh in electricity, 69 million pounds in CO2, and $2.5 million.

  13. Global climate change and terrestrial net primary production

    NASA Technical Reports Server (NTRS)

    Melillo, Jerry M.; Mcguire, A. D.; Kicklighter, David W.; Moore, Berrien, III; Vorosmarty, Charles J.; Schloss, Annette L.

    1993-01-01

    A process-based model was used to estimate global patterns of net primary production and soil nitrogen cycling for contemporary climate conditions and current atmospheric CO2 concentration. Over half of the global annual net primary production was estimated to occur in the tropics, with most of the production attributable to tropical evergreen forest. The effects of CO2 doubling and associated climate changes were also explored. The responses in tropical and dry temperate ecosystems were dominated by CO2, but those in northern and moist temperate ecosystems reflected the effects of temperature on nitrogen availability.

  14. Primary production of the cryptoendolithic microbiota from the Antarctic Desert

    NASA Technical Reports Server (NTRS)

    Vestal, J. R.; Friedmann, E. I. (Principal Investigator)

    1988-01-01

    Primary production in the Antarctic cryptoendolithic microbiota can be determined from biomass and photosynthetic 14CO2 incorporation measurements. Even though good nanoclimate data are available, it is difficult to determine the amount of time when abiotic conditions permit metabolism. Making appropriate assumptions concerning the metabolism of the cryptoendolithic microbiota during periods of warmth, light and moisture, the primary production of the biota was calculated to be on the order of 0.108 to 4.41 mgC/m2/yr, with a carbon turnover time from 576 to 23,520 years. These production values are the lowest found on planet Earth.

  15. Human Appropriation of Net Primary Production - Can Earth Keep Up?

    NASA Technical Reports Server (NTRS)

    Imhoff, Marc L.

    2006-01-01

    The amount of Earth's vegetation or net primary production required to support human activities is powerful measure of aggregate human impacts on the biosphere. Biophysical models applied to consumption statistics were used to estimate the annual amount of net primary production in the form of elemental carbon required for food, fibre, and fuel-wood by the global population. The calculations were then compared to satellite-based estimates of Earth's average net primary production to produce a geographically explicit balance sheet of net primary production "supply" and "demand". Humans consume 20% of Earth's net primary production (11.5 petagrams carbon) annually and this percentage varies regionally from 6% (South America) to over 70% (Europe and Asia), and locally from near 0% (central Australia) to over 30,000% (New York City, USA). The uneven footprint of human consumption and related environmental impacts, indicate the degree to which human populations are vulnerable to climate change and suggest policy options for slowing future growth of NPP demand.

  16. Rapid Aluminum Nanoparticle Production by Milling in NH₃ and CH₃NH₂ Atmospheres: An Experimental and Theoretical Study.

    PubMed

    McMahon, Brandon W; Yu, Jiang; Boatz, Jerry A; Anderson, Scott L

    2015-07-29

    Ball milling of aluminum in gaseous atmospheres of ammonia and monomethylamine (MMA) was found to produce particles in the 100 nm size range with high efficiency. A combination of mass spectrometry, X-ray photoelectron spectroscopy (XPS), thermogravimetric analysis with mass spectrometric product analysis (TGA-MS), scanning electron microscopy (SEM), infrared spectroscopy, and dynamic light scattering (DLS) was used to study the particles and the chemical interactions responsible for particle production. To help understand the nature of the surface chemistry, high level quantum chemical calculations were performed to predict the structures and energetics for binding and reactions of NH3 and MMA on aluminum surfaces. Both NH3 and MMA react with aluminum under milling conditions, producing H2 and other gaseous products, and leaving the surfaces functionalized. The surface functionalization enhances size reduction by reducing the surface free energy and the tendency toward mechanochemical welding. For both NH3 and MMA, the particle cores are metallic aluminum, but the surface chemical properties are quite different. The ammonia-milled particles are capped by an AlNxOyHz layer ∼10 nm thick, which passivates the particles. The MMA-milled particles are capped with a thinner passivating layer, such that they are pyrophoric in air and react with N2 at elevated temperatures. PMID:26132713

  17. Overcoming residual stresses and machining distortion in the production of aluminum alloy satellite boxes.

    SciTech Connect

    Younger, Mandy S.; Eckelmeyer, Kenneth Hall

    2007-11-01

    Distortion frequently occurs during machining of age hardening aluminum alloys due to residual stresses introduced during the quenching step in the heat treatment process. This report quantifies, compares, and discusses the effectiveness of several methods for minimizing residual stresses and machining distortion in aluminum alloys 7075 and 6061.

  18. Carbon Use Efficiency, and Net Primary Productivity of Terrestrial Vegetation

    NASA Astrophysics Data System (ADS)

    Choudhury, Bhaskar J.

    The carbon use efficiency (CUE), defined as the ratio of net carbon gain to gross carbon assimilation during a period, is a highly significant determinant of primary production of terrestrial plant communities. Available data for CUE is summarized. Then, a model for gross assimilation has been run using satellite and ancillary data to calculate annual net carbon gain or net primary productivity for the global land surface during four year period (1987-1990). The results are compared with other estimates. Interannual variability of 30-50% is found in some of the latitude bands

  19. Soil application of an aluminum industry by-product: Influences on soil chemistry and plant nutrition

    SciTech Connect

    Provin, T.L.; Joern, B.C.

    1996-11-01

    The recovery of metallic aluminum from furnace slag (skim) requires a fluxing salt to encapsulate metal oxides.A change from sodium chloride to potassium chloride (KCl) as a fluxing agent may allow for the annual agronomic land application of up to 2 million metric tons of this currently landfilled by-product. Both greenhouse and laboratory experiments were employed to study the influence of skim applications on soil and plant uptake of metals. In the greenhouse, KCl-enriched skim, KCl, and potassium sulfate were evaluated as potassium (K) fertilizers for wheat and alfalfa were grown on three soils and washed quartz sand. All K sources increased dry matter yields in both crops on all soils. Total metal analysis of tissue samples and analysis of soil pH, exchangeable base, and available phosphorus will also be presented. The utilization of a KCl-enrich skim product as a K fertilizer may provide an environmentally suitable alternative to landfills as well as an inexpensive source of K fertilizer to agriculture.

  20. Primary production control of methane emission from wetlands

    NASA Astrophysics Data System (ADS)

    Whiting, G. J.; Chanton, J. P.

    1993-08-01

    Based on simultaneous measurements of CO2 and CH4 exchange in wetlands extending from subarctic peatlands to subtropical marshes, a positive correlation between CH4 emission and net ecosystem production is reported. It is suggested that net ecosystem production is a master variable integrating many factors which control CH4 emission in vegetated wetlands. It is found that about 3 percent of the daily net ecosystem production is emitted back to the atmosphere as CH4. With projected stimulation of primary production and soil microbial activity in wetlands associated with elevated atmospheric CO2 concentration, the potential for increasing CH4 emission from inundated wetlands, further enhancing the greenhouse effect, is examined.

  1. Evaluation of primary production in Lake Erie by multiple proxies.

    PubMed

    Ostrom, Nathaniel E; Carrick, Hunter J; Twiss, Michael R; Piwinski, Leah

    2005-06-01

    Direct measurements of rates of primary production in Lake Erie are few and uncertainties surround rate measurements based on radiocarbon and the light-dark bottle incubation methods. For these reasons, we conducted a series of simultaneous primary productivity measurements in Lake Erie in July and August of 2003, based on incubation with [14C]-NaHCO3, the light-dark bottle method, and incubation with (18)O enriched water. Significant differences in the rates of primary production obtained by incubations with [(18)O]-H2O (0.19-34.60 mmol-O2 m(-3) h(-1)), [14C]-NaHCO3 (0.03-90.50 mmol-C m(-3) h(-1)), and light-dark bottles (0.06-60.78 mmol-O2 m(-3) h(-1)) were evident in six out of nine comparisons. Within the epilimnion, [(18)O]-H2O rates of primary production were significantly different from rates based on [14C]-NaHCO3 and light-dark bottles in all four comparisons and lower rates were obtained in three out of four comparisons. Eutrophic conditions in Sandusky Bay, Lake Erie were evident from the high primary production rates of 20.50-34.60 mmol-O2 m(-3) h(-1) ([(18)O]-H2O), 34.39-90.50 mmol-C m(-3) h(-1) ([14C]-NaHCO3), and 46.66-60.78 mmol-O2 m(-3) h(-1) (light-dark bottle). The photosynthetic quotient (PQ), or ratio of O2 production to CO2 consumption during photosynthesis, averaged 0.64+/-0.33 and 1.93+/-1.93, respectively, based on a comparison of [(18)O]-H2O to [14C]-NaHCO3 rates or light-dark bottle to [14C]-NaHCO3 production rates, respectively, demonstrating that photosynthesis in Lake Erie communities primarily follows expected stochiometric trends. The average of the ratio of production rates based on incubation with [(18)O]-H2O relative to those obtained by the light-dark incubation method was 0.66+/-0.33, indicating a tendency for the [(18)O]-H2O method to provide slightly lower estimates of production in Lake Erie. Lower estimates of primary production based on [(18)O]-H2O incubation relative to the other two approaches is most likely a consequence

  2. Decadal Changes in Global Ocean Annual Primary Production

    NASA Technical Reports Server (NTRS)

    Gregg, Watson; Conkright, Margarita E.; Behrenfeld, Michael J.; Ginoux, Paul; Casey, Nancy W.; Koblinsky, Chester J. (Technical Monitor)

    2002-01-01

    The Sea-viewing Wide Field-of-View Sensor (SeaWiFS) has produced the first multi-year time series of global ocean chlorophyll observations since the demise of the Coastal Zone Color Scanner (CZCS) in 1986. Global observations from 1997-present from SeaWiFS combined with observations from 1979-1986 from the CZCS should in principle provide an opportunity to observe decadal changes in global ocean annual primary production, since chlorophyll is the primary driver for estimates of primary production. However, incompatibilities between algorithms have so far precluded quantitative analysis. We have developed and applied compatible processing methods for the CZCS, using modern advances in atmospheric correction and consistent bio-optical algorithms to advance the CZCS archive to comparable quality with SeaWiFS. We applied blending methodologies, where in situ data observations are incorporated into the CZCS and SeaWiFS data records, to provide improvement of the residuals. These re-analyzed, blended data records provide maximum compatibility and permit, for the first time, a quantitative analysis of the changes in global ocean primary production in the early-to-mid 1980's and the present, using synoptic satellite observations. An intercomparison of the global and regional primary production from these blended satellite observations is important to understand global climate change and the effects on ocean biota. Photosynthesis by chlorophyll-containing phytoplankton is responsible for biotic uptake of carbon in the oceans and potentially ultimately from the atmosphere. Global ocean annual primary decreased from the CZCS record to SeaWiFS, by nearly 6% from the early 1980s to the present. Annual primary production in the high latitudes was responsible for most of the decadal change. Conversely, primary production in the low latitudes generally increased, with the exception of the tropical Pacific. The differences and similarities of the two data records provide evidence

  3. Seasonality of primary and secondary production in an Arctic river

    NASA Astrophysics Data System (ADS)

    Kendrick, M.; Huryn, A.; Deegan, L.

    2011-12-01

    Rivers and streams that freeze solid for 8-9 months each year provide excellent examples of the extreme seasonality of arctic habitats. The communities of organisms inhabiting these rivers must complete growth and development during summer, resulting in a rapid ramp-up and down of production over the short ice-free period. The effects of recent shifts in the timing of the spring thaw and autumn freeze-up on the duration and pattern of the period of active production are poorly understood. We are currently investigating: 1) the response of the biotic community of the Kuparuk River (Arctic Alaska) to shifts in the seasonality of the ice-free period, and 2) the community response to increases in phosphorous (P) supply anticipated as the volume of the permafrost active-layer increases in response to climate warming. Here algal production supports a 2-tier web of consumers. We tracked primary and secondary production from the spring thaw through mid-August in a reference reach and one receiving low-level P fertilization. Gross primary production/community respiration (GPP/R) ratios for both reaches were increasing through mid-July, with higher GPP/R in response to the P addition. Understanding the degree of synchrony between primary and secondary production in this Arctic river system will enhance further understanding of how shifts in seasonality affect trophic dynamics.

  4. Forecasting annual aboveground net primary production in the intermountain west

    Technology Transfer Automated Retrieval System (TEKTRAN)

    For many land manager’s annual aboveground net primary production, or plant growth, is a key factor affecting business success, profitability and each land manager's ability to successfully meet land management objectives. The strategy often utilized for forecasting plant growth is to assume every y...

  5. Deep-sea primary production at the Galapagos hydrothermal vents

    SciTech Connect

    Karl, D.M.; Wirsen, C.O.; Jannasch, H.W.

    1980-03-21

    Dense animal populations surrounding recently discovered hydrothermal vents at the Galapagos Rift sea-floor spreading center, 2550 meters deep, are probably sustained by microbial primary production. Energy in the form of geothermically reduced sulfur compounds emitted from the vents is liberated during oxidation and used for the reduction of carbon dioxide to organic matter by chemosynthetic bacteria.

  6. Estimation of primary dendrite arm spacings in continuous casting products

    SciTech Connect

    Cicutti, C.; Bilmes, P.; Boeri, R.

    1997-09-01

    The proportion of steels produced by continuous casting has grown drastically during the last two decades, increasing to such an extent that in some countries, several grades of steel are exclusively made by this process. Many investigations recognized the significant influence of the solidification structure on the quality of cast products, and pointed out the importance of the development of appropriate tools to predict the microstructure as a function of thermal and physical parameters. The estimation of secondary dendrite arm spacings in continuously cast steel products has received some attention. However, very little effort has been focused on the prediction of primary dendrite arm spacings, to the best of the authors` knowledge. The main objective of this study is to develop simple expressions to estimate the variation of primary dendrite arm spacings through the section of continuous casting steel products.

  7. Magnetic properties of the ammonolysis product of α-Fe powder containing a small amount of aluminum

    SciTech Connect

    Tsugawa, Yuta; Maubuchi, Yuji; Motohashi, Teruki; Kikkawa, Shinichi

    2015-02-15

    Magnetite was prepared containing a small amount of aluminum and its nitride was generated through low temperature ammonolysis following reduction under hydrogen. The nitrided product was determined by XRD to be a mixture of “α″-Fe{sub 16}N{sub 2}” having a slightly deformed crystal structure from α″-Fe{sub 16}N{sub 2} and the residual α-Fe. Magnetic coercivity of the mixture was decreased from the value of 150 mT obtained for the nitride product made without aluminum, due to the precipitation of nonmagnetic amorphous alumina in the low temperature nitrided bcc (Fe{sub 1−x}Al{sub x}) with x≤0.03. The aluminum-doped nitride product in which the “α″-Fe{sub 16}N{sub 2}” fraction was 30 at% exhibited magnetization at 1.5 T of approximately 200 Am{sup 2}kg{sup −1} at room temperature and its magnetic coercivity was 20 mT. - Graphical abstract: Magnetic iron nitride particles were separated by nonmagnetic amorphous γ-alumina. Magnetic coercivity was decreased by reducing the magnetic interaction between the particles. - Highlights: • Magnetic coercivity decreased in α”-Fe{sub 16}N{sub 2} like compound as a soft magnet. • Small amount of Al addition was effective in its preparation. • Magnetic interaction decreased between the “α”-Fe{sub 16}N{sub 2}” particles.

  8. Factors affecting the estimate of primary production from space

    NASA Technical Reports Server (NTRS)

    Balch, W. M.; Byrne, C. F.

    1994-01-01

    Remote sensing of primary production in the euphotic zone has been based mostly on visible-band and water-leaving radiance measured with the coastal zone color scanner. There are some robust, simple relationships for calculating integral production based on surface measurements, but they also require knowledge for photoadaptive parameters such as maximum photosynthesis which currently cannot be obtained from spave. A 17,000-station data set is used to show that space-based estimates of maximum photosynthesis could improve predictions of psi, the water column light utiliztion index, which is an important term in many primary productivity models. Temperature is also examined as a factor for predicting hydrographic structure and primary production. A simple model is used to relate temperature and maximum photosynthesis; the model incorporates (1) the positive relationship between maximum photosynthesis and temperature and (2) the strongly negative relationship between temperature and nitrate in the ocean (which directly affects maximum growth rates via nitrogen limitation). Since these two factors relate to carbon and nitrogen, 'balanced carbon/nitrogen assimilation' was calculated using the Redfield ratio, It is expected that the relationship between maximum balanced carbon assimilation versus temperature is concave-down, with the peak dependent on nitrate uptake kinetics, temperature-nitrate relationships,a nd the carbon chlorophyll ration. These predictions were compared with the sea truth data. The minimum turnover time for nitrate was also calculated using this approach. Lastly, sea surface temperature gradients were used to predict the slope of isotherms (a proxy for the slope of isopycnals in many waters). Sea truth data show that at size scales of several hundred kilometers, surface temperature gradients can provide information on the slope of isotherms in the top 200 m of the water column. This is directly relevant to the supply of nutrients into the surface

  9. Factors affecting the estimate of primary production from space

    NASA Astrophysics Data System (ADS)

    Balch, W. M.; Byrne, C. F.

    1994-04-01

    Remote sensing of primary production in the euphotic zone has been based mostly on visible-band water-leaving radiance measured with the coastal zone color scanner. There are some robust, simple relationships for calculating integral production based on surface measurements, but they also require knowledge of photoadaptive parameters such as maximum photosynthesis which currently cannot be obtained from space. A 17,000-station data set is used to show that space-based estimates of maximum photosynthesis could improve predictions of ψ, the water column light utilization index, which is an important term in many primary productivity models. Temperature is also examined as a factor for predicting hydrographic structure and primary production. A simple model is used to relate temperature and maximum photosynthesis; the model incorporates (1) the positive relationship between maximum photosynthesis and temperature and (2) the strongly negative relationship between temperature and nitrate in the ocean (which directly affects maximum growth rates via nitrogen limitation). Since these two factors relate to carbon and nitrogen, "balanced carbon/nitrogen assimilation" was calculated assuming the Redfield ratio. It is expected that the relationship between maximum balanced carbon assimilation versus temperature is concave-down, with the peak dependent on nitrate uptake kinetics, temperature-nitrate relationships, and the carbon/chlorophyll ratio. These predictions were compared with sea truth data. The minimum turnover time for nitrate was also calculated using this approach. Lastly, sea surface temperature gradients were used to predict the slope of isotherms (a proxy for the slope of isopycnals in many waters). Sea truth data show that at size scales of several hundred kilometers, surface temperature gradients can provide information on the slope of isotherms in the top 200 m of the water column. This is directly relevant to the supply of nutrients into the surface mixed

  10. The DART dispersion analysis research tool: A mechanistic model for predicting fission-product-induced swelling of aluminum dispersion fuels. User`s guide for mainframe, workstation, and personal computer applications

    SciTech Connect

    Rest, J.

    1995-08-01

    This report describes the primary physical models that form the basis of the DART mechanistic computer model for calculating fission-product-induced swelling of aluminum dispersion fuels; the calculated results are compared with test data. In addition, DART calculates irradiation-induced changes in the thermal conductivity of the dispersion fuel, as well as fuel restructuring due to aluminum fuel reaction, amorphization, and recrystallization. Input instructions for execution on mainframe, workstation, and personal computers are provided, as is a description of DART output. The theory of fission gas behavior and its effect on fuel swelling is discussed. The behavior of these fission products in both crystalline and amorphous fuel and in the presence of irradiation-induced recrystallization and crystalline-to-amorphous-phase change phenomena is presented, as are models for these irradiation-induced processes.

  11. Satellites for the study of ocean primary productivity

    NASA Technical Reports Server (NTRS)

    Smith, R. C.; Baker, K. S.

    1983-01-01

    The use of remote sensing techniques for obtaining estimates of global marine primary productivity is examined. It is shown that remote sensing and multiplatform (ship, aircraft, and satellite) sampling strategies can be used to significantly lower the variance in estimates of phytoplankton abundance and of population growth rates from the values obtained using the C-14 method. It is noted that multiplatform sampling strategies are essential to assess the mean and variance of phytoplankton biomass on a regional or on a global basis. The relative errors associated with shipboard and satellite estimates of phytoplankton biomass and primary productivity, as well as the increased statistical accuracy possible from the utilization of contemporaneous data from both sampling platforms, are examined. It is shown to be possible to follow changes in biomass and the distribution patterns of biomass as a function of time with the use of satellite imagery.

  12. Al/sub 2/S/sub 3/ preparation and use in electrolysis process for aluminum production

    DOEpatents

    Hsu, C.C.; Loutfy, R.O.; Yao, N.P.

    A continuous process for producing aluminum sulfide and for electrolyzing the aluminum sulfide to form metallic aluminum in which the aluminum sulfide is produced from aluminum oxide and COS or CS/sub 2/ in the presence of a chloride melt which also serves as the electrolysis bath. Circulation between the reactor and electrolysis cell is carried out to maintain the desired concentration of aluminum sulfide in the bath.

  13. (Polyfluoroaryl) fluoroanions of aluminum, gallium, and indium of enhanced utility, uses thereof, and products based thereon

    DOEpatents

    Marks, Tobin J.; Chen, You-Xian

    2002-01-01

    The (polyfluoroaryl)fluoroanions of aluminum, gallium, and indium are novel weakly coordinating anions which are highly fluorinated. (Polyfluoroaryl)fluoroanions of one such type contain at least one ring substituent other than fluorine. These (polyfluoroaryl)fluoroanions of aluminum, gallium, and indium have greater solubility in organic solvents, or have a coordinative ability essentially equal to or less than that of the corresponding (polyfluoroaryl)fluoroanion of aluminum, gallium, or indium in which the substituent is replaced by fluorine. Another type of new (polyfluoroaryl)fluoroanion of aluminum, gallium, and indium have 1-3 perfluorinated fused ring groups and 2-0 perfluorophenyl groups. When used as a cocatalyst in the formation of novel catalytic complexes with d- or f-block metal compounds having at least one leaving group such as a methyl group, these anions, because of their weak coordination to the metal center, do not interfere in the ethylene polymerization process, while affecting the propylene process favorably, if highly isotactic polypropylene is desired. Thus, the (polyfluoroaryl)fluoroanions of aluminum, gallium, and indium of this invention are useful in various polymerization processes such as are described.

  14. (Polyfluoroaryl) fluoroanions of aluminum, gallium, and indium of enhanced utility, uses thereof, and products based thereon

    DOEpatents

    Marks, Tobin J.; Chen, You-Xian

    2001-01-01

    The (polyfluoroaryl)fluoroanions of aluminum, gallium, and indium are novel weakly coordinating anions which are highly fluorinated. (Polyfluoroaryl)fluoroanions of one such type contain at least one ring substituent other than fluorine. These (polyfluoroaryl)fluoroanions of aluminum, gallium, and indium have greater solubility in organic solvents, or have a coordinative ability essentially equal to or less than that of the corresponding (polyfluoroaryl)fluoroanion of aluminum, gallium, or indium in which the substituent is replaced by fluorine. Another type of new (polyfluoroaryl)fluoroanion of aluminum, gallium, and indium have 1-3 perfluorinated fused ring groups and 2-0 perfluorophenyl groups. When used as a cocatalyst in the formation of novel catalytic complexes with d- or f-block metal compounds having at least one leaving group such as a methyl group, these anions, because of their weak coordination to the metal center, do not interfere in the ethylene polymerization process, while affecting the propylene process favorably, if highly isotactic polypropylene is desired. Thus, the (polyfluoroaryl)fluoroanions of aluminum, gallium, and indium of this invention are useful in various polymerization processes such as are described.

  15. Mineral phases and metals in baghouse dust from secondary aluminum production.

    PubMed

    Huang, Xiao-Lan; El Badawy, Amro M; Arambewela, Mahendranath; Adkins, Renata; Tolaymat, Thabet

    2015-09-01

    Baghouse dust (BHD) is a solid waste generated by air pollution control systems during secondary aluminum processing (SAP). Management and disposal of BHD can be challenging in the U.S. and elsewhere. In this study, the mineral phases, metal content and metal leachability of 78 BHD samples collected from 13 different SAP facilities across the U.S. were investigated. The XRD semi-quantitative analysis of BHD samples suggests the presence of metallic aluminum, aluminum oxide, aluminum nitride and its oxides, spinel, elpasolite as well as diaspora. BHD also contains halite, sylvite and fluorite, which are used as fluxes in SAP activities. Total aluminum (Al) in the BHD samples averaged 18% by weight. Elevated concentrations of trace metals (>100 μg L(-1) As; >1000 μg L(-1) Cu, Mn, Se, Pb, Mn and Zn) were also detected in the leachate. The U.S. toxicity characteristic leaching procedure (TCLP) results showed that some samples leached above the toxicity limit for Cd, Pb and Se. Exceeding the TCLP limits in all sample is independent of facilities generating the BHD. From the metal content perspective only, it appears that BHD has a higher potential to exhibit toxicity characteristics than salt cake (the largest waste stream generated by SAP facilities). PMID:25898346

  16. Mineral phases and metals in baghouse dust from secondary aluminum production.

    PubMed

    Huang, Xiao-Lan; El Badawy, Amro M; Arambewela, Mahendranath; Adkins, Renata; Tolaymat, Thabet

    2015-09-01

    Baghouse dust (BHD) is a solid waste generated by air pollution control systems during secondary aluminum processing (SAP). Management and disposal of BHD can be challenging in the U.S. and elsewhere. In this study, the mineral phases, metal content and metal leachability of 78 BHD samples collected from 13 different SAP facilities across the U.S. were investigated. The XRD semi-quantitative analysis of BHD samples suggests the presence of metallic aluminum, aluminum oxide, aluminum nitride and its oxides, spinel, elpasolite as well as diaspora. BHD also contains halite, sylvite and fluorite, which are used as fluxes in SAP activities. Total aluminum (Al) in the BHD samples averaged 18% by weight. Elevated concentrations of trace metals (>100 μg L(-1) As; >1000 μg L(-1) Cu, Mn, Se, Pb, Mn and Zn) were also detected in the leachate. The U.S. toxicity characteristic leaching procedure (TCLP) results showed that some samples leached above the toxicity limit for Cd, Pb and Se. Exceeding the TCLP limits in all sample is independent of facilities generating the BHD. From the metal content perspective only, it appears that BHD has a higher potential to exhibit toxicity characteristics than salt cake (the largest waste stream generated by SAP facilities).

  17. Biophsyical constraints on gross primary production by the terrestrial biosphere

    NASA Astrophysics Data System (ADS)

    Wang, H.; Prentice, I. C.; Davis, T. W.

    2014-10-01

    Persistent divergences among the predictions of complex carbon-cycle models include differences in the sign as well as the magnitude of the response of global terrestrial primary production to climate change. Such problems with current models indicate an urgent need to reassess the principles underlying the environmental controls of primary production. The global patterns of annual and maximum monthly terrestrial gross primary production (GPP) by C3 plants are explored here using a simple first-principles model based on the light-use efficiency formalism and the Farquhar model for C3 photosynthesis. The model is driven by incident photosynthetically active radiation (PAR) and remotely sensed green-vegetation cover, with additional constraints imposed by low-temperature inhibition and CO2 limitation. The ratio of leaf-internal to ambient CO2 concentration in the model responds to growing-season mean temperature, atmospheric dryness (indexed by the cumulative water deficit, Δ E) and elevation, based on an optimality theory. The greatest annual GPP is predicted for tropical moist forests, but the maximum (summer) monthly GPP can be as high, or higher, in boreal or temperate forests. These findings are supported by a new analysis of CO2 flux measurements. The explanation is simply based on the seasonal and latitudinal distribution of PAR combined with the physiology of photosynthesis. By successively imposing biophysical constraints, it is shown that partial vegetation cover - driven primarily by water shortage - represents the largest constraint on global GPP.

  18. Biophysical constraints on gross primary production by the terrestrial biosphere

    NASA Astrophysics Data System (ADS)

    Wang, H.; Prentice, I. C.; Davis, T. W.

    2014-02-01

    Persistent divergences among the predictions of complex carbon cycle models include differences in the sign as well as the magnitude of the response of global terrestrial primary production to climate change. This and other problems with current models indicate an urgent need to re-assess the principles underlying the environmental controls of primary production. The global patterns of annual and maximum monthly terrestrial gross primary production (GPP) by C3 plants are explored here using a simple first-principles model based on the light-use efficiency formalism and the Farquhar model for C3 photosynthesis. The model is driven by incident photosynthetically active radiation (PAR) and remotely sensed green vegetation cover, with additional constraints imposed by low-temperature inhibition and CO2 limitation. The ratio of leaf-internal to ambient CO2 concentration in the model responds to growing-season mean temperature, atmospheric dryness (indexed by the cumulative water deficit, ΔE) and elevation, based on optimality theory. The greatest annual GPP is predicted for tropical moist forests, but the maximum (summer) monthly GPP can be as high or higher in boreal or temperate forests. These findings are supported by a new analysis of CO2 flux measurements. The explanation is simply based on the seasonal and latitudinal distribution of PAR combined with the physiology of photosynthesis. By successively imposing biophysical constraints, it is shown that partial vegetation cover - driven primarily by water shortage - represents the largest constraint on global GPP.

  19. Regulation of primary productivity rate in the equatorial Pacific

    SciTech Connect

    Barber, R.T. ); Chavez, F.P. )

    1991-12-01

    Analysis of the Chl-specific rate of primary productivity (P{sup B}) as a function of subsurface nutrient concentration at >300 equatorial stations provides an answer to the question: What processes regulate primary productivity rate in the high-nutrient, low-chlorophyll waters of the equatorial Pacific In the western Pacific where there is a gradient in 60-m (NO{sub 3}) from 0 to {approximately}12 {mu}M, the productivity rate is a linear function of nutrient concentration; in the eastern Pacific where the gradient is from 12 to 28 {mu}M, the productivity rate is independent of nutrient concentration and limited to {approximately}36 mg C(mg Chl){sup {minus}1} d{sup {minus}1}, or a mean euphotic zone C-specific growth rate ({mu}) of 0.47 d{sup {minus}1}. However, rates downstream of the Galapagos Islands are not limited; they are 46.4 mg C(mg Chl){sup {minus}1} d{sup {minus}1} and {mu} = 0.57 d{sup {minus}1}, very close to the predicted nutrient-regulated rates in the absence of other limitation. This pattern of rate regulation can be accounted for by a combination of eolian Fe, subsurface nutrients, and sedimentary Fe derived from the Galapagos platform. In the low-nutrient western Pacific the eolian supply of Fe is adequate to allow productivity rate to be set by subsurface nutrient concentration. In the nutrient-rich easter equatorial region eolian Fe is inadequate to support productivity rates proportional to the higher nutrient concentrations, so in this region eolian Fe is rate limiting. Around the Galapagos Islands productivity rates reach levels consistent with nutrient concentrations; sedimentary Fe from the Galapagos platform seems adequate to support increased nutrient-regulated productivity rates in this region.

  20. Revised calibration of the Sm:SrB{sub 4}O{sub 7} pressure sensor using the Sm-doped yttrium-aluminum garnet primary pressure scale

    SciTech Connect

    Rashchenko, Sergey V. Litasov, Konstantin D.; Kurnosov, Alexander; Dubrovinsky, Leonid

    2015-04-14

    The pressure-induced shift of Sm:SrB{sub 4}O{sub 7} fluorescence was calibrated in a quasi-hydrostatic helium medium up to 60 GPa using the recent Sm-doped yttrium-aluminum garnet primary pressure scale as a reference. The resulting calibration can be written as P = −2836/14.3 [(1 + Δλ/685.51){sup −14.3 }− 1]. Previous calibrations based on the internally inconsistent primary scales are revised, and, after appropriate correction, found to agree with the proposed one. The calibration extended to 120 GPa was also performed using corrected previous data and can be written as P = 4.20 Δλ (1 + 0.020 Δλ)/(1 + 0.036 Δλ)

  1. Aluminum Carbothermic Technology

    SciTech Connect

    Bruno, Marshall J.

    2005-03-31

    This report documents the non-proprietary research and development conducted on the Aluminum Carbothermic Technology (ACT) project from contract inception on July 01, 2000 to termination on December 31, 2004. The objectives of the program were to demonstrate the technical and economic feasibility of a new carbothermic process for producing commercial grade aluminum, designated as the ''Advanced Reactor Process'' (ARP). The scope of the program ranged from fundamental research through small scale laboratory experiments (65 kW power input) to larger scale test modules at up to 1600 kW power input. The tasks included work on four components of the process, Stages 1 and 2 of the reactor, vapor recovery and metal alloy decarbonization; development of computer models; and economic analyses of capital and operating costs. Justification for developing a new, carbothermic route to aluminum production is defined by the potential benefits in reduced energy, lower costs and more favorable environmental characteristics than the conventional Hall-Heroult process presently used by the industry. The estimated metrics for these advantages include energy rates at approximately 10 kWh/kg Al (versus over 13 kWh/kg Al for Hall-Heroult), capital costs as low as $1250 per MTY (versus 4,000 per MTY for Hall-Heroult), operating cost reductions of over 10%, and up to 37% reduction in CO2 emissions for fossil-fuel power plants. Realization of these benefits would be critical to sustaining the US aluminum industries position as a global leader in primary aluminum production. One very attractive incentive for ARP is its perceived ability to cost effectively produce metal over a range of smelter sizes, not feasible for Hall-Heroult plants which must be large, 240,000 TPY or more, to be economical. Lower capacity stand alone carbothermic smelters could be utilized to supply molten metal at fabrication facilities similar to the mini-mill concept employed by the steel industry. Major

  2. An experimental aluminum-fueled power plant

    NASA Astrophysics Data System (ADS)

    Vlaskin, M. S.; Shkolnikov, E. I.; Bersh, A. V.; Zhuk, A. Z.; Lisicyn, A. V.; Sorokovikov, A. I.; Pankina, Yu. V.

    2011-10-01

    An experimental co-generation power plant (CGPP-10) using aluminum micron powder (with average particle size up to 70 μm) as primary fuel and water as primary oxidant was developed and tested. Power plant can work in autonomous (unconnected from industrial network) nonstop regime producing hydrogen, electrical energy and heat. One of the key components of experimental plant is aluminum-water high-pressure reactor projected for hydrogen production rate of ∼10 nm3 h-1. Hydrogen from the reactor goes through condenser and dehumidifier and with -25 °C dew-point temperature enters into the air-hydrogen fuel cell 16 kW-battery. From 1 kg of aluminum the experimental plant produces 1 kWh of electrical energy and 5-7 kWh of heat. Power consumer gets about 10 kW of electrical power. Plant electrical and total efficiencies are 12% and 72%, respectively.

  3. Cost-Effective Consolidation of Fine Aluminum Scrap for Increased Remelting Effieciency

    SciTech Connect

    William Van Geertruyden

    2005-09-22

    The main objective of this research was to develop a new re-melting process for fine or light gauge aluminum scrap products that exhibits dramatic improvements in energy efficiency. Light gauge aluminum scrap in the form of chips, turnings, and borings has historically been underutilized in the aluminum recycling process due to its high surface area to volume ratio resulting in low melt recovery. Laboratory scale consolidation experiments were performed using loose aluminum powder as a modeling material as well as shredded aluminum wire scrap. The processing parameters necessary to create consolidated aluminum material were determined. Additionally, re-melting experiments using consolidated and unconsolidated aluminum powder confirmed the hypothesis that metal recovery using consolidated material will significantly improve by as much as 20%. Based on this research, it is estimated that approximately 495 billion Btu/year can be saved by implementation of this technology in one domestic aluminum rolling plant alone. The energy savings are realized by substituting aluminum scrap for primary aluminum, which requires large amounts of energy to produce. While there will be an initial capital investment, companies will benefit from the reduction of dependence on primary aluminum thus saving considerable costs. Additionally, the technology will allow companies to maintain in-house alloy scrap, rather than purchasing from other vendors and eliminate the need to discard the light gauge scrap to landfills.

  4. Global net primary production and heterotrophic respiration for 1987

    SciTech Connect

    Hunt, R.E. Jr.; Piper, S.C.; Nemani, R. |

    1995-06-01

    An ecosystem process model, BIOME-BGC, was parameterized and used to simulate the actual net primary production and heterotrophic respiration using daily climatic data, land cover type, leaf area index gridded to 1{degree} latitude by 1{degree} longitude grid cells for the year 1987. Global net primary production was 52 Pg C. These estimates were validated directly by two different methods. First, the grid cells were aggregated and used as inputs to a 3D atmospheric transport model, to compare CO{sub 2} station data with predictions. We simulated the intra-annual variation of atmospheric CO{sub 2} well for the northern hemisphere, but not for the southern hemisphere. Second, we calculated the net {sup 13}C uptake of vegetation, which is a function of water use efficiency. The {sup 13}C/{sup 12}C ratios agreed with measured data, indicating a strong limitation of global primary processes by the hydrologic cycle, especially precipitation. These are different from other global carbon models as we can simulate the year-to-year variation of climate, including El Nino, on the global carbon cycle.

  5. Removing hydrochloric acid exhaust products from high performance solid rocket propellant using aluminum-lithium alloy.

    PubMed

    Terry, Brandon C; Sippel, Travis R; Pfeil, Mark A; Gunduz, I Emre; Son, Steven F

    2016-11-01

    Hydrochloric acid (HCl) pollution from perchlorate based propellants is well known for both launch site contamination, as well as the possible ozone layer depletion effects. Past efforts in developing environmentally cleaner solid propellants by scavenging the chlorine ion have focused on replacing a portion of the chorine-containing oxidant (i.e., ammonium perchlorate) with an alkali metal nitrate. The alkali metal (e.g., Li or Na) in the nitrate reacts with the chlorine ion to form an alkali metal chloride (i.e., a salt instead of HCl). While this technique can potentially reduce HCl formation, it also results in reduced ideal specific impulse (ISP). Here, we show using thermochemical calculations that using aluminum-lithium (Al-Li) alloy can reduce HCl formation by more than 95% (with lithium contents ≥15 mass%) and increase the ideal ISP by ∼7s compared to neat aluminum (using 80/20 mass% Al-Li alloy). Two solid propellants were formulated using 80/20 Al-Li alloy or neat aluminum as fuel additives. The halide scavenging effect of Al-Li propellants was verified using wet bomb combustion experiments (75.5±4.8% reduction in pH, ∝ [HCl], when compared to neat aluminum). Additionally, no measurable HCl evolution was detected using differential scanning calorimetry coupled with thermogravimetric analysis, mass spectrometry, and Fourier transform infrared absorption. PMID:27289269

  6. Mineral phases and metals in baghouse dust from secondary aluminum production

    EPA Science Inventory

    Baghouse dust (BHD) is a solid waste generated by air pollution control systems during secondary aluminum processing (SAP). Management and disposal of BHD can be challenging in the U.S. and elsewhere. In this study, the mineral phases, metal content and metal leachability of 78...

  7. Removing hydrochloric acid exhaust products from high performance solid rocket propellant using aluminum-lithium alloy.

    PubMed

    Terry, Brandon C; Sippel, Travis R; Pfeil, Mark A; Gunduz, I Emre; Son, Steven F

    2016-11-01

    Hydrochloric acid (HCl) pollution from perchlorate based propellants is well known for both launch site contamination, as well as the possible ozone layer depletion effects. Past efforts in developing environmentally cleaner solid propellants by scavenging the chlorine ion have focused on replacing a portion of the chorine-containing oxidant (i.e., ammonium perchlorate) with an alkali metal nitrate. The alkali metal (e.g., Li or Na) in the nitrate reacts with the chlorine ion to form an alkali metal chloride (i.e., a salt instead of HCl). While this technique can potentially reduce HCl formation, it also results in reduced ideal specific impulse (ISP). Here, we show using thermochemical calculations that using aluminum-lithium (Al-Li) alloy can reduce HCl formation by more than 95% (with lithium contents ≥15 mass%) and increase the ideal ISP by ∼7s compared to neat aluminum (using 80/20 mass% Al-Li alloy). Two solid propellants were formulated using 80/20 Al-Li alloy or neat aluminum as fuel additives. The halide scavenging effect of Al-Li propellants was verified using wet bomb combustion experiments (75.5±4.8% reduction in pH, ∝ [HCl], when compared to neat aluminum). Additionally, no measurable HCl evolution was detected using differential scanning calorimetry coupled with thermogravimetric analysis, mass spectrometry, and Fourier transform infrared absorption.

  8. Reduced temperature aluminum production in an electrolytic cell having an inert anode

    SciTech Connect

    Dawless, R.K.; Ray, S.P.; Hosler, R.B.; Kozarek, R.L.; LaCamera, A.F.

    2000-02-29

    Aluminum is produced by electrolytic reduction of alumina in a cell having a cathode, an inert anode and a molten salt bath containing metal fluorides and alumina. The inert anode preferably contains copper, silver and oxides of iron and nickel. Reducing the molten salt bath temperature to about 900--950 C lowers corrosion on the inert anode constituents.

  9. Reduced temperature aluminum production in an electrolytic cell having an inert anode

    SciTech Connect

    Dawless, Robert K.; Ray, Siba P.; Hosler, Robert B.; Kozarek, Robert L.; LaCamera, Alfred F.

    2000-01-01

    Aluminum is produced by electrolytic reduction of alumina in a cell having a cathode, an inert anode and a molten salt bath containing metal fluorides and alumina. The inert anode preferably contains copper, silver and oxides of iron and nickel. Reducing the molten salt bath temperature to about 900-950.degree. C. lowers corrosion on the inert anode constituents.

  10. 77 FR 8575 - National Emissions Standards for Hazardous Air Pollutants: Secondary Aluminum Production

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-02-14

    ... February 14, 2012 Part V Environmental Protection Agency 40 CFR Part 63 National Emissions Standards for... 63 RIN 2060-AQ40 National Emissions Standards for Hazardous Air Pollutants: Secondary Aluminum... proposing amendments to the national emissions standards for hazardous air pollutants for Secondary...

  11. Molecular biology in studies of oceanic primary production

    SciTech Connect

    LaRoche, J.; Falkowski, P.G. ); Geider, R. . Coll. of Marine Studies)

    1992-01-01

    Remote sensing and the use of moored in situ instrumentation has greatly improved our ability to measure phytoplankton chlorophyll and photosynthesis on global scales with high temporal resolution. However, the interpretation of these measurements and their significance with respect to the biogeochemical cycling of carbon relies on their relationship with physiological and biochemical processes in phytoplankton. For example, the use of satellite images of surface chlorophyll to estimate primary production is often based on the functional relationship between photosynthesis and irradiance. A variety of environmental factors such as light, temperature, nutrient availability affect the photosynthesis/irradiance (P vs I) relationship in phytoplankton. We present three examples showing how molecular biology can be used to provide basic insight into the factors controlling primary productivity at three different levels of complexity: 1. Studies of light intensity regulation in unicellular alga show how molecular biology can help understand the processing of environmental cues leading to the regulation of photosynthetic gene expression. 2. Probing of the photosynthetic apparatus using molecular techniques can be used to test existing mechanistic models derived from the interpretation of physiological and biophysical measurements. 3. Exploratory work on the expression of specific proteins during nutrient-limited growth of phytoplankton may lead to the identification and production of molecular probes for field studies.

  12. Molecular biology in studies of oceanic primary production

    SciTech Connect

    LaRoche, J.; Falkowski, P.G.; Geider, R.

    1992-07-01

    Remote sensing and the use of moored in situ instrumentation has greatly improved our ability to measure phytoplankton chlorophyll and photosynthesis on global scales with high temporal resolution. However, the interpretation of these measurements and their significance with respect to the biogeochemical cycling of carbon relies on their relationship with physiological and biochemical processes in phytoplankton. For example, the use of satellite images of surface chlorophyll to estimate primary production is often based on the functional relationship between photosynthesis and irradiance. A variety of environmental factors such as light, temperature, nutrient availability affect the photosynthesis/irradiance (P vs I) relationship in phytoplankton. We present three examples showing how molecular biology can be used to provide basic insight into the factors controlling primary productivity at three different levels of complexity: 1. Studies of light intensity regulation in unicellular alga show how molecular biology can help understand the processing of environmental cues leading to the regulation of photosynthetic gene expression. 2. Probing of the photosynthetic apparatus using molecular techniques can be used to test existing mechanistic models derived from the interpretation of physiological and biophysical measurements. 3. Exploratory work on the expression of specific proteins during nutrient-limited growth of phytoplankton may lead to the identification and production of molecular probes for field studies.

  13. Connected speech production in three variants of primary progressive aphasia

    PubMed Central

    Henry, Maya L.; Besbris, Max; Ogar, Jennifer M.; Dronkers, Nina F.; Jarrold, William; Miller, Bruce L.; Gorno-Tempini, Maria Luisa

    2010-01-01

    Primary progressive aphasia is a clinical syndrome defined by progressive deficits isolated to speech and/or language, and can be classified into non-fluent, semantic and logopenic variants based on motor speech, linguistic and cognitive features. The connected speech of patients with primary progressive aphasia has often been dichotomized simply as ‘fluent’ or ‘non-fluent’, however fluency is a multidimensional construct that encompasses features such as speech rate, phrase length, articulatory agility and syntactic structure, which are not always impacted in parallel. In this study, our first objective was to improve the characterization of connected speech production in each variant of primary progressive aphasia, by quantifying speech output along a number of motor speech and linguistic dimensions simultaneously. Secondly, we aimed to determine the neuroanatomical correlates of changes along these different dimensions. We recorded, transcribed and analysed speech samples for 50 patients with primary progressive aphasia, along with neurodegenerative and normal control groups. Patients were scanned with magnetic resonance imaging, and voxel-based morphometry was used to identify regions where atrophy correlated significantly with motor speech and linguistic features. Speech samples in patients with the non-fluent variant were characterized by slow rate, distortions, syntactic errors and reduced complexity. In contrast, patients with the semantic variant exhibited normal rate and very few speech or syntactic errors, but showed increased proportions of closed class words, pronouns and verbs, and higher frequency nouns, reflecting lexical retrieval deficits. In patients with the logopenic variant, speech rate (a common proxy for fluency) was intermediate between the other two variants, but distortions and syntactic errors were less common than in the non-fluent variant, while lexical access was less impaired than in the semantic variant. Reduced speech rate

  14. Global impact of tropical cyclones on primary production

    NASA Astrophysics Data System (ADS)

    Menkes, Christophe E.; Lengaigne, Matthieu; Lévy, Marina; Ethé, Christian; Bopp, Laurent; Aumont, Olivier; Vincent, Emmanuel; Vialard, Jérôme; Jullien, Swen

    2016-05-01

    In this paper, we explore the global responses of surface temperature, chlorophyll, and primary production to tropical cyclones (TCs). Those ocean responses are first characterized from the statistical analysis of satellite data under ~1000 TCs over the 1998-2007 period. Besides the cold wake, the vast majority of TCs induce a weak chlorophyll response, with only ~10% of induced blooms exceeding 0.1 mg m-3. The largest chlorophyll responses mostly occur within coastal regions, in contrast to the strongest cold wakes that generally occur farther offshore. To understand this decoupling, we analyze a coupled dynamical-biogeochemical oceanic simulation forced by realistic wind vortices applied along observed TC tracks. The simulation displays a realistic spatial structure of TC-induced blooms and its observed decoupling with TC cold wakes. In regions of strong TC energy input, the strongest cold wakes occur in regions of shallow thermocline (<60 m) and the strongest blooms in regions of shallow nitracline and/or subsurface chlorophyll maximum (<60 m). Shallow thermoclines are found over many open ocean regions, while regions of shallow nitracline and/or subsurface chlorophyll maximum are most prominent in near-coastal areas, explaining the spatial decoupling between the cold and bloom wakes. The overall TC contribution to annual primary production is weak and amounts to ~1%, except in a few limited areas (east Eurasian coast, South tropical Indian Ocean, Northern Australian coast, and Eastern Pacific Ocean in the TC-prone region) where it can locally reach up to 20-30%. Nearly 80% of this TC-induced annual primary production is the result of the biogeochemical response to the 30% strongest TCs.

  15. A global land primary productivity and phytogeography model

    SciTech Connect

    Woodward, F.I.; Smith, T.M.; Emanuel, W.R.

    1995-12-01

    A global primary productivity and phytogeography model is described. The model represents the biochemical processes of photosynthesis and the dependence of gas exchange on stomatal conductance, which in turn depends on temperature and soil moisture. Canopy conductance controls soil water loss by evapotranspiration. The assignment of nitrogen uptake to leaf layers is proportional to irradiance, and respiration and maximum assimilation rates depend on nitrogen uptake and temperature. Total nitrogen uptake is derived from soil carbon and nitrogen and depends on temperature. The long-term average annual carbon and hydrological budgets dictate canopy leaf area. Although observations constrain soil carbon and nitrogen, the distribution of vegetation types is not specified by an underlying map. Variables simulated by the model are compared to experimental results. These comparisons extend from biochemical processes to the whole canopy, and the comparisons are favorable for both current and elevated CO{sub 2} atmospheres. The model is used to simulate the global distributions of leaf area index and annual net primary productivity. These distributions are sufficiently realistic to demonstrate that the model is useful for analyzing vegetation responses to global environmental change. 116 refs., 11 figs.

  16. Ohio Aluminum Industries: Compressed air system improvement project saves energy and improves product quality

    SciTech Connect

    None, None

    2003-11-01

    In 2001, Ohio Aluminum Industries implemented the first phase of a compressed air system improvement project at its Cleveland, Ohio, plant. By completing this phase, the plant stabilized the system's pressure and improved its performance. Furthermore, it yielded annual energy savings of 716,000 kilowatt-hours and $73,200. The total cost for the project's first phase was $83,500, making the simple payback slightly more than 1 year.

  17. Production of Gas-Solid Structures in Aluminum and Nickel Alloys by Gasar Processing

    SciTech Connect

    Apprill, J.M.; Baldwin, M.D.; Maguire, M.C.; Miszkiel, M.E.; Shapovalov, V.I.

    1999-01-06

    Experimental data on directional and bulk solidification of hydrogen-charged samples of aluminum alloy A356 and nickel alloy Inconel 718 are discussed. The solidification structure of the porous zone is shown to be dependent on many process variables. Of these variables, hydrogen content in the melt prior to solidification, and furnace atmospheric pressure during solidification play the decisive role. Also important are the furnace atmosphere composition, the solidification velocity, and the temperature distribution of the liquid metal inside the mold.

  18. Evaluation of Primary Dendrite Arm Spacings from Aluminum-7wt% Silicon alloys Directionally Solidified aboard the International Space Station - Comparison with Theory

    NASA Technical Reports Server (NTRS)

    Angart, Samuel; Lauer, Mark; Poirier, David; Tewari, Surendra; Rajamure, Ravi; Grugel, Richard

    2015-01-01

    Aluminum – 7wt% silicon alloys were directionally solidified in the microgravity environment aboard the International Space Station as part of the “MIcrostructure Formation in CASTing of Technical Alloys under Diffusive and Magnetically Controlled Convective Conditions” (MICAST) European led program. Cross-sections of the sample during periods of steady-state growth were metallographically prepared from which the primary dendrite arm spacing (lambda 1) was measured. These spacings were found to be in reasonable agreement with the Hunt-Lu model which assumes a diffusion-controlled, convectionless, environment during controlled solidification. Deviation from the model was found and is attributed to gravity-independent thermocapillary convection where, over short distances, the liquid appears to have separated from the crucible wall.

  19. Process Conditions of Forming the Surface Layer of Aluminum Powder Product by Layer-by-layer Laser Sintering

    NASA Astrophysics Data System (ADS)

    Saprykina, N. A.; Saprykin, A. A.; Ibragimov, E. A.; Arkhipova, D. A.

    2016-07-01

    The paper presents data on state of the art in selective laser sintering of products. Layer-by-layer sintering is shown to be a future-oriented technology, making it possible to synthesize products of metal powder materials. Factors, influencing the quality of a sintered product, are revealed in the paper. It presents outcomes of experiments, focused on the dependence of surface layer thickness of sintered aluminum powder PA-4 on laser processing conditions. Basic factors, influencing the quality of a sintered surface layer include laser power, speeds of scanning and moving the laser beam on the layer of powder. Thickness of the sintered layer varies from 0.74 to 1.55 mm, as the result of changing the laser processing conditions.

  20. Electrically conductive anodized aluminum coatings

    NASA Technical Reports Server (NTRS)

    Alwitt, Robert S. (Inventor); Liu, Yanming (Inventor)

    2001-01-01

    A process for producing anodized aluminum with enhanced electrical conductivity, comprising anodic oxidation of aluminum alloy substrate, electrolytic deposition of a small amount of metal into the pores of the anodized aluminum, and electrolytic anodic deposition of an electrically conductive oxide, including manganese dioxide, into the pores containing the metal deposit; and the product produced by the process.

  1. Phytoplankton primary production in the world's estuarine-coastal ecosystems

    NASA Astrophysics Data System (ADS)

    Cloern, J. E.; Foster, S. Q.; Kleckner, A. E.

    2014-05-01

    Estuaries are biogeochemical hot spots because they receive large inputs of nutrients and organic carbon from land and oceans to support high rates of metabolism and primary production. We synthesize published rates of annual phytoplankton primary production (APPP) in marine ecosystems influenced by connectivity to land - estuaries, bays, lagoons, fjords and inland seas. Review of the scientific literature produced a compilation of 1148 values of APPP derived from monthly incubation assays to measure carbon assimilation or oxygen production. The median value of median APPP measurements in 131 ecosystems is 185 and the mean is 252 g C m-2 yr-1, but the range is large: from -105 (net pelagic production in the Scheldt Estuary) to 1890 g C m-2 yr-1 (net phytoplankton production in Tamagawa Estuary). APPP varies up to 10-fold within ecosystems and 5-fold from year to year (but we only found eight APPP series longer than a decade so our knowledge of decadal-scale variability is limited). We use studies of individual places to build a conceptual model that integrates the mechanisms generating this large variability: nutrient supply, light limitation by turbidity, grazing by consumers, and physical processes (river inflow, ocean exchange, and inputs of heat, light and wind energy). We consider method as another source of variability because the compilation includes values derived from widely differing protocols. A simulation model shows that different methods reported in the literature can yield up to 3-fold variability depending on incubation protocols and methods for integrating measured rates over time and depth. Although attempts have been made to upscale measures of estuarine-coastal APPP, the empirical record is inadequate for yielding reliable global estimates. The record is deficient in three ways. First, it is highly biased by the large number of measurements made in northern Europe (particularly the Baltic region) and North America. Of the 1148 reported values of

  2. Phytoplankton primary production in the world's estuarine-coastal ecosystems

    USGS Publications Warehouse

    Cloern, James E.; Foster, S.Q.; Kleckner, A.E.

    2014-01-01

    Estuaries are biogeochemical hot spots because they receive large inputs of nutrients and organic carbon from land and oceans to support high rates of metabolism and primary production. We synthesize published rates of annual phytoplankton primary production (APPP) in marine ecosystems influenced by connectivity to land – estuaries, bays, lagoons, fjords and inland seas. Review of the scientific literature produced a compilation of 1148 values of APPP derived from monthly incubation assays to measure carbon assimilation or oxygen production. The median value of median APPP measurements in 131 ecosystems is 185 and the mean is 252 g C m−2 yr−1, but the range is large: from −105 (net pelagic production in the Scheldt Estuary) to 1890 g C m−2 yr−1 (net phytoplankton production in Tamagawa Estuary). APPP varies up to 10-fold within ecosystems and 5-fold from year to year (but we only found eight APPP series longer than a decade so our knowledge of decadal-scale variability is limited). We use studies of individual places to build a conceptual model that integrates the mechanisms generating this large variability: nutrient supply, light limitation by turbidity, grazing by consumers, and physical processes (river inflow, ocean exchange, and inputs of heat, light and wind energy). We consider method as another source of variability because the compilation includes values derived from widely differing protocols. A simulation model shows that different methods reported in the literature can yield up to 3-fold variability depending on incubation protocols and methods for integrating measured rates over time and depth. Although attempts have been made to upscale measures of estuarine-coastal APPP, the empirical record is inadequate for yielding reliable global estimates. The record is deficient in three ways. First, it is highly biased by the large number of measurements made in northern Europe (particularly the Baltic region) and North America. Of the 1148

  3. Energy Efficient Aluminum Production - Pilot-Scale Cell Tests - Final Report for Phase I and Phase II

    SciTech Connect

    R. A. Christini

    1999-12-30

    A cermet anode that produces oxygen and a cathode material that is wetted by aluminum can provide a dimensionally stable inter-electrode distance in the Hall-Heroult cell. This can be used to greatly improve the energy and/or productivity efficiencies. The concept, which was developed and tested, uses a system of vertically interleaved anodes and cathodes. The major advantage of this concept is the significant increase in electrochemical surface area compared to a horizontal orientation of anode and cathode that is presently used in the Hall-Heroult process. This creates an additional advantage for energy reduction of 1.3 kWh/lb or a 20% productivity improvement. The voltages obtained in an optimized cell test met the energy objectives of the project for at least two weeks. An acceptable current efficiency was never proven, however, during either pilot scale or bench scale tests with the vertical plate configuration. This must be done before a vertical cell can be considered viab le. Anode corrosion rate must be reduced by at least a factor of three in order to produce commercial purity aluminum. It is recommended that extensive theoretical and bench scale investigations be done to improve anode materials and to demonstrate acceptable current efficiencies in a vertical plate cell before pilot scale work is continued.

  4. 9 CFR 113.51 - Requirements for primary cells used for production of biologics.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 9 Animals and Animal Products 1 2010-01-01 2010-01-01 false Requirements for primary cells used... VECTORS STANDARD REQUIREMENTS Ingredient Requirements § 113.51 Requirements for primary cells used for production of biologics. Primary cells used to prepare biological products shall be derived from...

  5. 9 CFR 113.51 - Requirements for primary cells used for production of biologics.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 9 Animals and Animal Products 1 2014-01-01 2014-01-01 false Requirements for primary cells used... VECTORS STANDARD REQUIREMENTS Ingredient Requirements § 113.51 Requirements for primary cells used for production of biologics. Primary cells used to prepare biological products shall be derived from...

  6. 9 CFR 113.51 - Requirements for primary cells used for production of biologics.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 9 Animals and Animal Products 1 2012-01-01 2012-01-01 false Requirements for primary cells used... VECTORS STANDARD REQUIREMENTS Ingredient Requirements § 113.51 Requirements for primary cells used for production of biologics. Primary cells used to prepare biological products shall be derived from...

  7. 9 CFR 113.51 - Requirements for primary cells used for production of biologics.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 9 Animals and Animal Products 1 2011-01-01 2011-01-01 false Requirements for primary cells used... VECTORS STANDARD REQUIREMENTS Ingredient Requirements § 113.51 Requirements for primary cells used for production of biologics. Primary cells used to prepare biological products shall be derived from...

  8. 9 CFR 113.51 - Requirements for primary cells used for production of biologics.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 9 Animals and Animal Products 1 2013-01-01 2013-01-01 false Requirements for primary cells used... VECTORS STANDARD REQUIREMENTS Ingredient Requirements § 113.51 Requirements for primary cells used for production of biologics. Primary cells used to prepare biological products shall be derived from...

  9. Achieving Carbon Neutrality in the Global Aluminum Industry

    NASA Astrophysics Data System (ADS)

    Das, Subodh

    2012-02-01

    In the 21st century, sustainability is widely regarded as the new corporate culture, and leading manufacturing companies (Toyota, GE, and Alcoa) and service companies (Google and Federal Express) are striving towards carbon neutrality. The current carbon footprint of the global aluminum industry is estimated at 500 million metric tonnes carbon dioxide equivalent (CO2eq), representing about 1.7% of global emissions from all sources. For the global aluminum industry, carbon neutrality is defined as a state where the total "in-use" CO2eq saved from all products in current use, including incremental process efficiency improvements, recycling, and urban mining activities, equals the CO2eq expended to produce the global output of aluminum. This paper outlines an integrated and quantifiable plan for achieving "carbon neutrality" in the global aluminum industry by advocating five actionable steps: (1) increase use of "green" electrical energy grid by 8%, (2) reduce process energy needs by 16%, (3) deploy 35% of products in "in-use" energy saving applications, (4) divert 6.1 million metric tonnes/year from landfills, and (5) mine 4.5 million metric tonnes/year from aluminum-rich "urban mines." Since it takes 20 times more energy to make aluminum from bauxite ore than to recycle it from scrap, the global aluminum industry could set a reasonable, self-imposed energy/carbon neutrality goal to incrementally increase the supply of recycled aluminum by at least 1.05 metric tonnes for every tonne of incremental production via primary aluminum smelter capacity. Furthermore, the aluminum industry can and should take a global leadership position by actively developing internationally accepted and approved carbon footprint credit protocols.

  10. Method of producing complex aluminum alloy parts of high temper, and products thereof

    NASA Technical Reports Server (NTRS)

    Wilson, I. J. (Inventor)

    1978-01-01

    Fully annealed aluminum sheet is first stretch formed to the complex, doubly compound shape of a previously prepared forming die, e.g., an ejection seat blowout panel of a shuttlecraft. The part is then marked with a series of grid lines for monitoring later elongation. Thereafter it is solution heat treated and refrigerated to retard hardening. While still soft, it is stretched a second time on the same die to induce a modicum of work hardening, after which it is aged to the desired stress corrosion resistant temper, preferably the T8 level, to provide the desired hardness and stress corrosion resistance.

  11. Primary productivity and its correlation with rainfall on Aldabra Atoll

    NASA Astrophysics Data System (ADS)

    Shekeine, J.; Turnbull, L. A.; Cherubini, P.; de Jong, R.; Baxter, R.; Hansen, D.; Bunbury, N.; Fleischer-Dogley, F.; Schaepman-Strub, G.

    2015-01-01

    Aldabra Atoll, a UNESCO World Heritage Site since 1982, hosts the world's largest population of giant tortoises. In view of recent rainfall declines in the East African region, it is important to assess the implications of local rainfall trends on the atoll's ecosystem and evaluate potential threats to the food resources of the giant tortoises. However, building an accurate picture of the effects of climate change requires detailed context-specific case-studies, an approach often hindered by data deficiencies in remote areas. Here, we present and analyse a new historical rainfall record of Aldabra atoll together with two potential measures of primary productivity: (1) tree-ring measurements of the deciduous tree species Ochna ciliata and, (2) satellite-derived NDVI (normalized difference vegetation index) data for the period 2001-2012. Rainfall declined by about 6 mm yr-1 in the last four decades, in agreement with general regional declines, and this decline could mostly be attributed to changes in wet-season rainfall. We were unable to cross-date samples of O. ciliata with sufficient precision to deduce long-term patterns of productivity. However, satellite data were used to derive Aldabra's land surface phenology (LSP) for the period 2001-2012 which was then linked to rainfall seasonality. This relationship was strongest in the eastern parts of the atoll (with a time-lag of about six weeks between rainfall changes and LSP responses), an area dominated by deciduous grasses that supports high densities of tortoises. While the seasonality in productivity, as reflected in the satellite record, is correlated with rainfall, we did not find any change in mean rainfall or productivity for the shorter period 2001-2012. The sensitivity of Aldabra's vegetation to rainfall highlights the potential impact of increasing water stress in East Africa on the region's endemic ecosystems.

  12. Aluminum Hydroxide

    MedlinePlus

    Aluminum hydroxide is used for the relief of heartburn, sour stomach, and peptic ulcer pain and to ... Aluminum hydroxide comes as a capsule, a tablet, and an oral liquid and suspension. The dose and ...

  13. Primary production, sinking fluxes and the microbial food web

    NASA Astrophysics Data System (ADS)

    Michaels, Anthony F.; Silver, Mary W.

    1988-04-01

    The size distribution of pelagic producers and the size and trophic position of consumers determine the composition and magnitude of sinking fluxes from the surface communities in a simple model of oceanic food webs. Picoplankton, the dominant producers in the model, contribute little to the sinking material, due primarily to the large number of trophic steps between picoplankton and the consumers that produce the sinking particles. Net phytoplankton are important contributors to the sinking materials, despite accounting for a small fraction of the total primary production. These net phytoplankton, especially those capable of nitrogen fixation, also dominate the fraction of the new production that is exported on its first pass through the food chain. The sinking flux is strongly determined by the community structure of the consumers and varies by an order of magnitude for different food webs. The model indicates that generalist grazers, zooplankton that consume a broad size spectrum of prey (including pico-and nanoplankton), play a critical role in exporting particles. The role of generalists that occasionally form swarms, such as thaliaceans (salps and doliolids), can be particularly difficult to assess. Short-term studies probably miss the relatively infrequent population blooms of these grazers, events that could control the average, long-term exports from surface oceanic communities.

  14. Estimating Net Primary Productivity Using Satellite and Ancillary Data

    NASA Technical Reports Server (NTRS)

    Choudhury, Bhaskar J.

    2002-01-01

    The net primary productivity (C) or the annual rate of carbon accumulation per unit ground area by terrestrial plant communities is the difference of gross photosynthesis (A(sub g)) and respiration (R) per unit ground area. Available field observations show that R is a large and variable fraction of A(sub g), although it is generally recognized that there are considerable difficulties in determining these fluxes, and thus pose challenge in assessing the accuracy. Further uncertainties arise in extrapolating field measurements (which are acquired over a hectare or so area) to regional scale. Here, an approach is presented for determining these fluxes using satellite and ancillary data to be representative of regional scale and allow assessment of interannual variation. A, has been expressed as the product of radiation use efficiency for gross photosynthesis by an unstressed canopy and intercepted photosynthetically active radiation, which is then adjusted for stresses due to soil water shortage and temperature away from optimum. R has been calculated as the sum of growth and maintenance components (respectively, R(sub g) and R(sub m)).The R(sub m) has been determined from nitrogen content of plant tissue per unit ground area, while R(sub g) has been obtained as a fraction of the difference of A(sub g) and R(sub m). Results for five consecutive years (1986-1990) are presented for the Amazon-Tocontins, Mississippi, and Ob River basins.

  15. Widespread methanotrophic primary production in lowland chalk rivers

    PubMed Central

    Shelley, Felicity; Grey, Jonathan; Trimmer, Mark

    2014-01-01

    Methane is oversaturated relative to the atmosphere in many rivers, yet its cycling and fate is poorly understood. While photosynthesis is the dominant source of autotrophic carbon to rivers, chemosynthesis and particularly methane oxidation could provide alternative sources of primary production where the riverbed is heavily shaded or at depth beneath the sediment surface. Here, we highlight geographically widespread methanotrophic carbon fixation within the gravel riverbeds of over 30 chalk rivers. In 15 of these, the potential for methane oxidation (methanotrophy) was also compared with photosynthesis. In addition, we performed detailed concurrent measurements of photosynthesis and methanotrophy in one large chalk river over a complete annual cycle, where we found methanotrophy to be active to at least 15 cm into the riverbed and to be strongly substrate limited. The seasonal trend in methanotrophic activity reflected that of the riverine methane concentrations, and thus the highest rates were measured in mid-summer. At the sediment surface, photosynthesis was limited by light for most of the year with heavy shading induced by dense beds of aquatic macrophytes. Across 15 rivers, in late summer, we conservatively calculated that net methanotrophy was equivalent to between 1% and 46% of benthic net photosynthetic production within the gravel riverbed, with a median value of 4%. Hence, riverbed chemosynthesis, coupled to the oxidation of methane, is widespread and significant in English chalk rivers. PMID:24695425

  16. Photo-ionization of aluminum in a hot cavity for the selective production of exotic species project

    NASA Astrophysics Data System (ADS)

    Scarpa, D.; Makhathini, L.; Tomaselli, A.; Grassi, D.; Corradetti, S.; Manzolaro, M.; Vasquez, J.; Calderolla, M.; Rossignoli, M.; Monetti, A.; Andrighetto, A.; Prete, G.

    2014-02-01

    SPES (Selective Production of Exotic Species) is an Isotope Separation On-Line (ISOL) based accelerator facility that will be built in the Legnaro-Istituto Nazionale di Fisica Nucleare (INFN) Laboratory (Italy), intended to provide intense neutron-rich radioactive ion beams obtained by proton-induced fission of a uranium carbide (UCx) target. Besides this main target material, silicon carbide (SiC) will be the first to be used to deliver p-rich beams. This target will also validate the functionality of the SPES facility with aluminum beam as result of impinging SiC target with proton beam. In the past, off line studies on laser photoionization of aluminum have been performed in Pavia Spectroscopy Laboratory and in Laboratori Nazionali di Legnaro; a XeCl excimer laser was installed in order to test the laser ionization in the SPES hot cavity. With the new Wien filter installed a better characterization of the ionization process in terms of efficiency was performed and results are discussed.

  17. Photo-ionization of aluminum in a hot cavity for the selective production of exotic species project

    SciTech Connect

    Scarpa, D. Corradetti, S.; Manzolaro, M.; Vasquez, J.; Calderolla, M.; Rossignoli, M.; Monetti, A.; Andrighetto, A.; Prete, G.; Makhathini, L.; Tomaselli, A.; Grassi, D.

    2014-02-15

    SPES (Selective Production of Exotic Species) is an Isotope Separation On-Line (ISOL) based accelerator facility that will be built in the Legnaro-Istituto Nazionale di Fisica Nucleare (INFN) Laboratory (Italy), intended to provide intense neutron-rich radioactive ion beams obtained by proton-induced fission of a uranium carbide (UCx) target. Besides this main target material, silicon carbide (SiC) will be the first to be used to deliver p-rich beams. This target will also validate the functionality of the SPES facility with aluminum beam as result of impinging SiC target with proton beam. In the past, off line studies on laser photoionization of aluminum have been performed in Pavia Spectroscopy Laboratory and in Laboratori Nazionali di Legnaro; a XeCl excimer laser was installed in order to test the laser ionization in the SPES hot cavity. With the new Wien filter installed a better characterization of the ionization process in terms of efficiency was performed and results are discussed.

  18. Preparation of a nanodispersed aluminum hydroxide-based binder used for the production of refractory corundum ceramics

    NASA Astrophysics Data System (ADS)

    Vetchinkina, T. N.; Lainer, Yu. A.; Averin, V. V.; Olyunina, T. V.

    2015-03-01

    The preparation of the rehydrated metastable ρ phase of alumina with a large specific surface based on domestic aluminum hydroxide is studied in order to develop a method for producing a calcium-free binder (analog of the α-Bond binder produced abroad by the Almatis company for the preparation of corundum refractories with a high thermal stability). Three types of aluminum hydroxide specimens from three enterprises, i.e., obtained from different raw materials and by different methods, are studied. The specimens with a specific surface smaller than ~240 m2/g represented by the η-, χ-, ν-, θ-, ρ,and δ-Al2O3 structural modifications are isolated due to "impact" dehydration. The dehydration of Al(OH)3 under reduced pressures is studied. The product with a phase composition closest to that of the α-Bond binder is obtained under an impact thermal load at 600°C and a rarefaction of 0.01 MPa.

  19. The allocation of ecosystem net primary productivity in tropical forests

    PubMed Central

    Malhi, Yadvinder; Doughty, Christopher; Galbraith, David

    2011-01-01

    The allocation of the net primary productivity (NPP) of an ecosystem between canopy, woody tissue and fine roots is an important descriptor of the functioning of that ecosystem, and an important feature to correctly represent in terrestrial ecosystem models. Here, we collate and analyse a global dataset of NPP allocation in tropical forests, and compare this with the representation of NPP allocation in 13 terrestrial ecosystem models. On average, the data suggest an equal partitioning of allocation between all three main components (mean 34 ± 6% canopy, 39 ± 10% wood, 27 ± 11% fine roots), but there is substantial site-to-site variation in allocation to woody tissue versus allocation to fine roots. Allocation to canopy (leaves, flowers and fruit) shows much less variance. The mean allocation of the ecosystem models is close to the mean of the data, but the spread is much greater, with several models reporting allocation partitioning outside of the spread of the data. Where all main components of NPP cannot be measured, litterfall is a good predictor of overall NPP (r2 = 0.83 for linear fit forced through origin), stem growth is a moderate predictor and fine root production a poor predictor. Across sites the major component of variation of allocation is a shifting allocation between wood and fine roots, with allocation to the canopy being a relatively invariant component of total NPP. This suggests the dominant allocation trade-off is a ‘fine root versus wood’ trade-off, as opposed to the expected ‘root–shoot’ trade-off; such a trade-off has recently been posited on theoretical grounds for old-growth forest stands. We conclude by discussing the systematic biases in estimates of allocation introduced by missing NPP components, including herbivory, large leaf litter and root exudates production. These biases have a moderate effect on overall carbon allocation estimates, but are smaller than the observed range in allocation values across sites. PMID

  20. Climate change enhances primary production in the western Antarctic Peninsula.

    PubMed

    Moreau, Sébastien; Mostajir, Behzad; Bélanger, Simon; Schloss, Irene R; Vancoppenolle, Martin; Demers, Serge; Ferreyra, Gustavo A

    2015-06-01

    Intense regional warming was observed in the western Antarctic Peninsula (WAP) over the last 50 years. Here, we investigate the impact of climate change on primary production (PP) in this highly productive region. This study is based on temporal data series of ozone thickness (1972-2010), sea ice concentration (1978-2010), sea-surface temperature (1990-2010), incident irradiance (1988-2010) and satellite-derived chlorophyll a concentration (Chl-a, 1997-2010) for the coastal WAP. In addition, we apply a photosynthesis/photoinhibition spectral model to satellite-derived data (1997-2010) to compute PP and examine the separate impacts of environmental forcings. Since 1978, sea ice retreat has been occurring earlier in the season (in March in 1978 and in late October during the 2000s) while the ozone hole is present in early spring (i.e. August to November) since the early 1990s, increasing the intensity of ultraviolet-B radiation (UVBR, 280-320 nm). The WAP waters have also warmed over 1990-2010. The modelled PP rates are in the lower range of previously reported PP rates in the WAP. The annual open water PP in the study area increased from 1997 to 2010 (from 0.73 to 1.03 Tg C yr(-1) ) concomitantly with the increase in the production season length. The coincidence between the earlier sea ice retreat and the presence of the ozone hole increased the exposure to incoming radiation (UVBR, UVAR and PAR) and, thus, increased photoinhibition during austral spring (September to November) in the study area (from 0.014 to 0.025 Tg C yr(-1) ). This increase in photoinhibition was minor compared to the overall increase in PP, however. Climate change hence had an overall positive impact on PP in the WAP waters. PMID:25626857

  1. Investigating the potential for subsurface primary production fueled by serpentinization

    NASA Astrophysics Data System (ADS)

    Brazelton, W. J.; Nelson, B. Y.; Schrenk, M. O.

    2011-12-01

    Ultramafic rocks in the Earth's mantle represent a tremendous reservoir of carbon and reducing power. Tectonic uplift of these materials into the crust can result in serpentinization, a highly exothermic geochemical reaction that releases hydrogen gas (H2) and promotes the abiogenic synthesis of organic molecules. The extent and activity of microbial communities in serpentinite-hosted subsurface habitats is almost entirely unknown, but they clearly have great potential to host extensive sunlight-independent primary production fueled by H2 and abiotic carbon compounds. We have been testing this hypothesis at several sites of serpentinization around the globe utilizing a suite of techniques including metagenomics, 16S rRNA pyrotag sequencing, and stable isotope tracing experiments. All four of our study sites, which include deep-sea hydrothermal vents, terrestrial alkaline springs, and continental drill holes, are characteristically low in archaeal and bacterial genetic diversity. In carbonate chimneys of the Lost City hydrothermal field (Mid-Atlantic Ridge), for example, a single archaeal phylotype dominates the biofilm community. Stable isotope tracing experiments indicated that these archaeal biofilms are capable of both production and anaerobic oxidation of methane at 80C and pH 10. Both production and oxidation were stimulated by H2, suggesting a possible syntrophic relationship among cells within the biofilm. Preliminary results from similar stable isotope tracing experiments at terrestrial alkaline seeps at the Tablelands Ophiolite (Newfoundland), Ligurian springs (Italy), and McLaughlin Reserve (California) have indicated the potential for microbial activity fueled by H2 and acetate. Furthermore, recent metagenomic sequencing of fluids from the Tablelands and Ligurian springs have revealed genomic potential for chemolithotrophy powered by iron reduction with H2. In summary, these data support the potential for extensive microbial activity fueled by

  2. Mineralogical and physical considerations related to the separation and recovery of constituents from aluminum smelter by-products and wastes

    SciTech Connect

    Plumpton, A.J.; Wilhelmy, J.F.; Blackburn, D.; Caouette, J.L.

    1996-10-01

    Several by-products and waste products of aluminum smelting were characterized mineralogically and physically, in order to evaluate the potential for their decontamination or separation and recovery into valuable products using mineral processing techniques. The test samples were selected from among Bayer process red mud, bath-alumina mixture, cleaned anode butts, anode recycle residues, spent potlining, saltcake and fluorogypsum. Several of these materials were shown to be composed either of highly liberated, potentially separable mineral phases, or of locked minerals which could be partially liberated by grinding to smaller but practical particle sizes. An analysis of specific physical properties of the liberated constituent mineral phases was accompanied by preliminary experimental evaluation of their separability. An assessment was made of potential mineral processing techniques including size and form differentiation, gravitational and magnetic field separation, flotation, separation based on surface charging phenomena or work function, and pneumatic tabling. The results confirmed the suitability of low-cost physical separation techniques for the treatment of some by-products and wastes. This paper presents results of a preliminary evaluation of two smelter products. The conference paper will analyze and discuss in more detail the potential for the mineral processing of these and other smelter by-products and wastes.

  3. Occupational exposure to beryllium in primary aluminium production.

    PubMed

    Skaugset, Nils Petter; Ellingsen, Dag G; Dahl, Kari; Martinsen, Ivar; Jordbekken, Lars; Drabløs, Per Arne; Thomassen, Yngvar

    2012-02-01

    Alumina used in the production of primary aluminium contains Be which partly vaporises from the cryolite bath into the workroom atmosphere. Since Be may be toxic at lower exposure levels than previously thought, the personal exposure to Be among workers in 7 Norwegian primary smelters has been assessed. In total, 480 personal Respicon® virtual impactor full shift air samples have been collected during 2 sampling campaigns and analysed for water soluble Be, Al and Na using inductively coupled plasma optical emission spectrometry. In addition, water soluble F(-) has been measured by ion chromatography. The Be air concentrations in the inhalable, thoracic and respirable aerosol fractions have been calculated. The Be concentrations in the inhalable aerosol fraction vary between the different smelters. The highest GM concentration of Be in the inhalable fraction (122 ng m(-3), n = 30) was measured in the prebake pot room of a smelter using predominantly Jamaican alumina where also the highest individual air concentration of 270 ng m(-3) of Be was identified. The relative distribution of Be in the different aerosol fractions was fairly constant with the mean Be amount for the two sampling campaigns between 44-49% in the thoracic fraction expressed as % of the inhalable amount. Linear regression analysis shows a high correlation between water soluble Be, Al, F and Na describing an average measured chemical bulk composition of the water soluble thoracic fraction as Na(5.7)Al(3.1)F(18). Be is likely to be present as traces in this particulate matter by replacing Al atoms in the condensed fluorides and/or as a major element in a nanoparticle sized fluoride. Thus, the major amount of Be present in the work room atmosphere of Al smelter pot rooms will predominantly be present in combination with substantial amounts of water soluble Al, F and Na. PMID:21993554

  4. Degradation of net primary production in a semiarid rangeland

    NASA Astrophysics Data System (ADS)

    Jackson, Hasan; Prince, Stephen D.

    2016-08-01

    Anthropogenic land degradation affects many biogeophysical processes, including reductions of net primary production (NPP). Degradation occurs at scales from small fields to continental and global. While measurement and monitoring of NPP in small areas is routine in some studies, for scales larger than 1 km2, and certainly global, there is no regular monitoring and certainly no attempt to measure degradation. Quantitative and repeatable techniques to assess the extent of deleterious effects and monitor changes are needed to evaluate its effects on, for example, economic yields of primary products such as crops, lumber, and forage, and as a measure of land surface properties which are currently missing from dynamic global vegetation models, assessments of carbon sequestration, and land surface models of heat, water, and carbon exchanges. This study employed the local NPP scaling (LNS) approach to identify patterns of anthropogenic degradation of NPP in the Burdekin Dry Tropics (BDT) region of Queensland, Australia, from 2000 to 2013. The method starts with land classification based on the environmental factors presumed to control (NPP) to group pixels having similar potential NPP. Then, satellite remotely sensing data were used to compare actual NPP with its potential. The difference in units of mass of carbon and percentage loss were the measure of degradation. The entire BDT (7.45 × 106 km2) was investigated at a spatial resolution of 250 × 250 m. The average annual reduction in NPP due to anthropogenic land degradation in the entire BDT was -2.14 MgC m-2 yr-1, or 17 % of the non-degraded potential, and the total reduction was -214 MgC yr-1. Extreme average annual losses of 524.8 gC m-2 yr-1 were detected. Approximately 20 % of the BDT was classified as "degraded". Varying severities and rates of degradation were found among the river basins, of which the Belyando and Suttor were highest. Interannual, negative trends in reductions of NPP occurred in 7 % of the

  5. Palaeoenvironmental Indications of Enhanced Primary Productivity During Pliocene Sapropel Formation

    NASA Astrophysics Data System (ADS)

    Menzel, D.; Hopmans, E. C.; Schouten, S.; van Bergen, P. F.; Sinninghe Damste, J. S.

    2001-12-01

    Cores taken during the Ocean Drilling Program (ODP) Leg 160 in the eastern Mediterranean basin revealed periodic, laminated intervals with high organic contents, i.e. sapropels (Emeis et al., 1996). These include Pliocene sediments showing cyclic variations in organic matter deposition strongly correlated to the precession cyclicity of the Earth's orbit (e.g. Rossignol-Strick, 1985; Lourens et al., 1996a). The two main causes for sapropel formation are either climate-related enhanced organic matter productivity and/or increased preservation due to oxygen depletion of the bottom waters (e.g. Calvert et al., 1992; Canfield, 1994). Increased productivity is suggested to be the driving force in generating euxinic conditions leading to sapropel deposition (e.g. Passier et al., 1999). Photic zone euxinia was most probably triggered by large-scale input of nutrients from the Nile and other rivers leading to enhanced primary productivity and consequently high organic matter fluxes. This was based on concentrations of isorenieratene, a biomarker of photic zone euxinia, studied in three lateral time-equivalent Pliocene sapropels (subm. Menzel et al., 2001). Photic zone euxinia was more pronounced at the central and western part of the eastern Mediterranean basin, when compared with the most eastern part, where a deepening of the chemocline resulted from the increased delivery of fresh water. Using additional biomarkers will provide detailed insights in palaeoenvironmental changes that caused high organic matter deposition. The quantitative analysis of compounds specific for phytoplankton classes, e.g. isololiolides and loliolides reflecting Bacillariophyta, C37 - C39 alkenones indicative of Prymnesiophyta etc., will result in reconstruction of compositions of the standing crop and changes thereof at the time of deposition. The quantitative analysis of long-chain n-alkanes, indicating higher land plants, could reveal river input into the basin. Carbon isotope compositions of

  6. Crop gross primary productivity estimation using Landsat and MODIS data

    NASA Astrophysics Data System (ADS)

    Peng, Y.; Gitelson, A. A.; Sakamoto, T.; Masek, J. G.; Rundquist, D. C.; Verma, S. B.; Suyker, A. E.; Baker, J. M.; Hatfield, J.; Meyers, T. P.

    2012-12-01

    In this study, a paradigm was considered to assess gross primary productivity (GPP) in crops via the estimation of total crop chlorophyll (Chl) content. Based on this paradigm, a simple model was developed to estimate crop GPP using a product of Chl-related vegetation index (VI), retrieved from MODIS 250 m and Landsat data, and potential photosynthetically active radiation (PAR). Potential PAR is incident photosynthetically active radiation under a condition of minimal atmospheric aerosol loading. This model is based entirely on satellite data, and it was tested for maize and soybean GPP estimation, which are contrasting crop types different in leaf structures and canopy architectures, under different crop managements and climatic conditions. Using Landsat data, this model was able to accurately estimate GPP in maize-soybean croplands in Mead, Nebraska during growing seasons 2001 through 2008. The indices using green and NIR Landsat bands were found to be the most accurate in GPP estimation with coefficients of variation (CV) below 13% for maize and 15% for soybean. The algorithms established in the Nebraska AmeriFlux sites were validated for the same crops in AmeriFlux sites in Minnesota, Iowa and Illinois. Using MODIS 250 m data, with much higher temporal resolution than Landsat data, the model was capable of estimating GPP accurately in both irrigated and rainfed croplands. Among the MODIS-250 m retrieved indices tested, EVI and WDRVI were the most accurate for GPP estimation with CV below 20% in maize and 25% in soybean. It showed that the developed model was quite sensitive to detect GPP variation in crops where total Chl content is closely tied to seasonal dynamic of GPP.

  7. Controls on the ratio of mesozooplankton production to primary production in marine ecosystems

    NASA Astrophysics Data System (ADS)

    Stock, Charles; Dunne, John

    2010-01-01

    An ecosystem model was used to (1) determine the extent to which global trends in the ratio of mesozooplankton production to primary production (referred to herein as the " z-ratio") can be explained by nutrient enrichment, temperature, and euphotic zone depth, and (2) quantitatively diagnose the mechanisms driving these trends. Equilibrium model solutions were calibrated to observed and empirically derived patterns in phytoplankton biomass and growth rates, mesozooplankton biomass and growth rates, and the fraction of phytoplankton that are large (>5 μm ESD). This constrained several otherwise highly uncertain model parameters. Most notably, half-saturation constants for zooplankton feeding were constrained by the biomass and growth rates of their prey populations, and low zooplankton basal metabolic rates were required to match observations from oligotrophic ecosystems. Calibrated model solutions had no major biases and produced median z-ratios and ranges consistent with estimates. However, much of the variability around the median values in the calibration dataset (72 points) could not be explained. Model results were then compared with an extended global compilation of z-ratio estimates (>10 000 points). This revealed a modest yet significant ( r=0.40) increasing trend in z-ratios from values ˜0.01-0.04 to ˜0.1-0.2 with increasing primary productivity, with the transition from low to high z-ratios occurring at lower primary productivity in cold-water ecosystems. Two mechanisms, both linked to increasing phytoplankton biomass, were responsible: (1) zooplankton gross growth efficiencies increased as their ingestion rates became much greater than basal metabolic rates and (2) the trophic distance between primary producers and mesozooplankton shortened as primary production shifted toward large phytoplankton. Mechanism (1) was most important during the transition from low to moderate productivity ecosystems and mechanism (2) was responsible for a relatively

  8. Stratospheric sulfate geoengineering enhances terrestrial gross primary productivity

    NASA Astrophysics Data System (ADS)

    Xia, L.; Robock, A.; Tilmes, S.; Neely, R. R., III

    2015-09-01

    Stratospheric sulfate geoengineering could impact the terrestrial carbon cycle by enhancing the carbon sink. With an 8 Tg yr-1 injection of SO2 to balance a Representative Concentration Pathway 6.0 (RCP6.0) scenario, we conducted climate model simulations with the Community Earth System Model, with the Community Atmospheric Model 4 fully coupled to tropospheric and stratospheric chemistry (CAM4-chem). During the geoengineering period, as compared to RCP6.0, land-averaged downward visible diffuse radiation increased 3.2 W m-2 (11 %). The enhanced diffuse radiation combined with the cooling increased plant photosynthesis by 2.4 %, which could contribute to an additional 3.8 ± 1.1 Gt C yr-1 global gross primary productivity without nutrient limitation. This increase could potentially increase the land carbon sink. Suppressed plant and soil respiration due to the cooling would reduce natural land carbon emission and therefore further enhance the terrestrial carbon sink during the geoengineering period. This beneficial impact of stratospheric sulfate geoengineering would need to be balanced by a large number of potential risks in any future decisions about implementation of geoengineering.

  9. Estimation of gross primary production capacity from global satellite observations

    NASA Astrophysics Data System (ADS)

    Muramatsu, Kanako; Thanyapraneedkul, Juthasinee; Furumi, Shinobu; Soyama, Noriko; Daigo, Motomasa

    2012-10-01

    To estimate gross primary production (GPP), the process of photosynthesis was considered as two separate phases: capacity and reduction. The reduction phase is influenced by environmental conditions such as soil moisture and weather conditions such as vapor pressure differences. For a particular leaf, photosynthetic capacity mainly depends on the amount of chlorophyll and the RuBisCO enzyme. The chlorophyll content can be estimated by the color of the leaf, and leaf color can be detected by optical sensors. We used the chlorophyll content of leaves to estimate the level of GPP. A previously developed framework for GPP capacity estimation employs a chlorophyll index. The index is based on the linear relationship between the chlorophyll content of a leaf and the maximum photosynthesis at PAR =2000 (μmolm -2s-1) on a light-response curve under low stress conditions. As a first step, this study examined the global distribution of the index and found that regions with high chlorophyll index values in winter corresponded to tropical rainforest areas. The seasonal changes in the chlorophyll index differed from those shown by the normalized difference vegetation index. Next, the capacity of GPP was estimated from the light-response curve using the index. Most regions exhibited a higher GPP capacity than that estimated from Moderate Resolution Imaging Spectroradiometer (MODIS) observations, except in areas of tropical rainforest, where the GPP capacity and the MODIS GPP estimates were almost identical.

  10. Gross primary production of global forest ecosystems has been overestimated

    PubMed Central

    Ma, Jianyong; Yan, Xiaodong; Dong, Wenjie; Chou, Jieming

    2015-01-01

    Coverage rate, a critical variable for gridded forest area, has been neglected by previous studies in estimating the annual gross primary production (GPP) of global forest ecosystems. In this study, we investigated to what extent the coverage rate could impact forest GPP estimates from 1982 to 2011. Here we show that the traditional calculation without considering the coverage rate globally overestimated the forest gross carbon dioxide uptake by approximately 8.7%, with a value of 5.12 ± 0.23 Pg C yr−1, which is equivalent to 48% of the annual emissions from anthropogenic activities in 2012. Actually, the global annual GPP of forest ecosystems is approximately 53.71 ± 4.83 Pg C yr−1 for the past 30 years by taking the coverage rate into account. Accordingly, we argue that forest annual GPP calculated by previous studies has been overestimated due to the exaggerated forest area, and therefore, coverage rate may be a required factor to further quantify the global carbon cycle. PMID:26027557

  11. Natural organic matter as global antennae for primary production.

    PubMed

    Van Trump, J Ian; Rivera Vega, Fransheska J; Coates, John D

    2013-05-01

    Humic substances (HS) are high-molecular-weight complex refractory organics that are ubiquitous in terrestrial and aquatic environments. While resistant to microbial degradation, these compounds nevertheless support microbial metabolism via oxidation or reduction of their (hydro)quinone moieties. As such, they are known to be important electron sinks for respiratory and fermentative bacteria and electron sources for denitrifying and perchlorate-reducing bacteria. HS also strongly promote abiotic reduction of Fe(III) when irradiated with light. Here, we show that HS-enhanced Fe(III) photoreduction can also drive chemolithotrophic microbial respiration by producing Fe(II), which functions as a respiratory electron donor. Due to their molecular complexity, HS absorb most of the electromagnetic spectrum and can act as broad-spectrum antennae converting radiant energy into bioavailable chemical energy. The finding that chemolithotrophic organisms can utilize this energy has important implications for terrestrial, and possibly extraterrestrial, microbial processes and offers an alternative mechanism of radiation-driven primary productivity to that of phototrophy.

  12. Phase III Advanced Anodes and Cathodes Utilized in Energy Efficient Aluminum Production Cells

    SciTech Connect

    R.A. Christini; R.K. Dawless; S.P. Ray; D.A. Weirauch, Jr.

    2001-11-05

    During Phase I of the present program, Alcoa developed a commercial cell concept that has been estimated to save 30% of the energy required for aluminum smelting. Phase ii involved the construction of a pilot facility and operation of two pilots. Phase iii of the Advanced Anodes and Cathodes Program was aimed at bench experiments to permit the resolution of certain questions to be followed by three pilot cells. All of the milestones related to materials, in particular metal purity, were attained with distinct improvements over work in previous phases of the program. NiO additions to the ceramic phase and Ag additions to the Cu metal phase of the cermet improved corrosion resistance sufficiently that the bench scale pencil anodes met the purity milestones. Some excellent metal purity results have been obtained with anodes of the following composition: Further improvements in anode material composition appear to be dependent on a better understanding of oxide solubilities in molten cryolite. For that reason, work was commissioned with an outside consultant to model the MeO - cryolite systems. That work has led to a better understanding of which oxides can be used to substitute into the NiO-Fe2O3 ceramic phase to stabilize the ferrites and reduce their solubility in molten cryolite. An extensive number of vertical plate bench electrolysis cells were run to try to find conditions where high current efficiencies could be attained. TiB2-G plates were very inconsistent and led to poor wetting and drainage. Pure TiB2 did produce good current efficiencies at small overlaps (shadowing) between the anodes and cathodes. This bench work with vertical plate anodes and cathodes reinforced the importance of good cathode wetting to attain high current efficiencies. Because of those conclusions, new wetting work was commissioned and became a major component of the research during the third year of Phase III. While significant progress was made in several areas, much work needs to be

  13. Global cropland monthly Gross Primary Production in the year 2000

    NASA Astrophysics Data System (ADS)

    Chen, T.; van der Werf, G. R.; Gobron, N.; Moors, E. J.; Dolman, A. J.

    2014-02-01

    Croplands cover about 12% of the ice-free terrestrial land surface. Compared with natural ecosystems, croplands have distinct characteristics due to anthropogenic influences. Their global gross primary production (GPP) is not well constrained and estimates vary between 8.2 and 14.2 Pg C yr-1. We quantified global cropland GPP using a light use efficiency (LUE) model, employing satellite observations and survey data of crop types and distribution. A novel step in our analysis was to assign a maximum light use efficiency estimate (ε*GPP) to each of the 26 different crop types, instead of taking a uniform value as done in the past. These ε*GPP values were calculated based on flux tower CO2 exchange measurements and a literature survey of field studies, and ranged from 1.20 g CMJ-1 to 2.96 g CMJ-1. Global cropland GPP was estimated to be 11.05 Pg C yr-1 in the year 2000. Maize contributed most to this (1.55 Pg C yr-1), and the continent of Asia contributed most with 38.9% of global cropland GPP. In the continental United States, annual cropland GPP (1.28 Pg C yr-1) was close to values reported previously (1.24 Pg C yr-1) constrained by harvest records, but our estimates of ε*GPP values were much higher. Our results are sensitive to satellite information and survey data on crop type and extent, but provide a consistent and data-driven approach to generate a look-up table of ε*GPP for the 26 crop types for potential use in other vegetation models.

  14. Global cropland monthly gross primary production in the year 2000

    NASA Astrophysics Data System (ADS)

    Chen, T.; van der Werf, G. R.; Gobron, N.; Moors, E. J.; Dolman, A. J.

    2014-07-01

    Croplands cover about 12% of the ice-free terrestrial land surface. Compared with natural ecosystems, croplands have distinct characteristics due to anthropogenic influences. Their global gross primary production (GPP) is not well constrained and estimates vary between 8.2 and 14.2 Pg C yr-1. We quantified global cropland GPP using a light use efficiency (LUE) model, employing satellite observations and survey data of crop types and distribution. A novel step in our analysis was to assign a maximum light use efficiency estimate (ϵ*GPP) to each of the 26 different crop types, instead of taking a uniform value as done in the past. These ϵ*GPP values were calculated based on flux tower CO2 exchange measurements and a literature survey of field studies, and ranged from 1.20 to 2.96 g C MJ-1. Global cropland GPP was estimated to be 11.05 Pg C yr-1 in the year 2000. Maize contributed most to this (1.55 Pg C yr-1), and the continent of Asia contributed most with 38.9% of global cropland GPP. In the continental United States, annual cropland GPP (1.28 Pg C yr-1) was close to values reported previously (1.24 Pg C yr-1) constrained by harvest records, but our estimates of ϵ*GPP values were considerably higher. Our results are sensitive to satellite information and survey data on crop type and extent, but provide a consistent and data-driven approach to generate a look-up table of ϵ*GPP for the 26 crop types for potential use in other vegetation models.

  15. Spatiotemporal patterns of terrestrial gross primary production: A review

    NASA Astrophysics Data System (ADS)

    Anav, Alessandro; Friedlingstein, Pierre; Beer, Christian; Ciais, Philippe; Harper, Anna; Jones, Chris; Murray-Tortarolo, Guillermo; Papale, Dario; Parazoo, Nicholas C.; Peylin, Philippe; Piao, Shilong; Sitch, Stephen; Viovy, Nicolas; Wiltshire, Andy; Zhao, Maosheng

    2015-09-01

    Great advances have been made in the last decade in quantifying and understanding the spatiotemporal patterns of terrestrial gross primary production (GPP) with ground, atmospheric, and space observations. However, although global GPP estimates exist, each data set relies upon assumptions and none of the available data are based only on measurements. Consequently, there is no consensus on the global total GPP and large uncertainties exist in its benchmarking. The objective of this review is to assess how the different available data sets predict the spatiotemporal patterns of GPP, identify the differences among data sets, and highlight the main advantages/disadvantages of each data set. We compare GPP estimates for the historical period (1990-2009) from two observation-based data sets (Model Tree Ensemble and Moderate Resolution Imaging Spectroradiometer) to coupled carbon-climate models and terrestrial carbon cycle models from the Fifth Climate Model Intercomparison Project and TRENDY projects and to a new hybrid data set (CARBONES). Results show a large range in the mean global GPP estimates. The different data sets broadly agree on GPP seasonal cycle in terms of phasing, while there is still discrepancy on the amplitude. For interannual variability (IAV) and trends, there is a clear separation between the observation-based data that show little IAV and trend, while the process-based models have large GPP variability and significant trends. These results suggest that there is an urgent need to improve observation-based data sets and develop carbon cycle modeling with processes that are currently treated either very simplistically to correctly estimate present GPP and better quantify the future uptake of carbon dioxide by the world's vegetation.

  16. Estimating Net Primary Productivity Using Satellite and Ancillary Data

    NASA Technical Reports Server (NTRS)

    Choudhury, B. J.; Houser, Paul (Technical Monitor)

    2001-01-01

    The net primary productivity (C) or annual rate of carbon accumulation per unit ground area by terrestrial plant communities is the difference of the rate of gross photosynthesis (A(sub g)) and autotrophic respiration (R) per unit ground area. Although available observations show that R is a large and variable fraction of A(sub g), viz., 0.3 to 0.7, it is generally recognized that much uncertainties exist in this fraction due to difficulties associated with the needed measurements. Additional uncertainties arise when these measurements are extrapolated to regional or global land surface using empirical equations, for example, using regression equations relating C to mean annual precipitation and air temperature. Here, a process-based approach has been taken to calculate A(sub g) and R using satellite and ancillary data. A(sub g) has been expressed as a product of radiation use efficiency, magnitude of intercepted photosynthetically active radiation (PAR), and normalized by stresses due to soil water shortage and air temperature away from the optimum range. A biophysical model has been used to determine the radiation use efficiency from the maximum rate of carbon assimilation by a leaf, foliage temperature, and the fraction of diffuse PAR incident on a canopy. All meteorological data (PAR, air temperature, precipitation, etc.) needed for the calculation are derived from satellite observations, while a land use, land cover data (based on satellite and ground measurements) have been used to assess the maximum rate of carbon assimilation by a leaf of varied cover type based on field measurements. R has been calculated as the sum of maintenance and growth components. The maintenance respiration of foliage and live fine roots at a standard temperature of different land cover has been determined from their nitrogen content using field and satellite measurements, while that of living fraction of woody stem (viz., sapwood) from the seasonal maximum leaf area index as

  17. Alkali-Soluble Pectin Is the Primary Target of Aluminum Immobilization in Root Border Cells of Pea (Pisum sativum).

    PubMed

    Yang, Jin; Qu, Mei; Fang, Jing; Shen, Ren Fang; Feng, Ying Ming; Liu, Jia You; Bian, Jian Feng; Wu, Li Shu; He, Yong Ming; Yu, Min

    2016-01-01

    We investigated the hypothesis that a discrepancy of Al binding in cell wall constituents determines Al mobility in root border cells (RBCs) of pea (Pisum sativum), which provides protection for RBCs and root apices under Al toxicity. Plants of pea (P. sativum L. 'Zhongwan no. 6') were subjected to Al treatments under mist culture. The concentration of Al in RBCs was much higher than that in the root apex. The Al content in RBCs surrounding one root apex (10(4) RBCs) was approximately 24.5% of the total Al in the root apex (0-2.5 mm), indicating a shielding role of RBCs for the root apex under Al toxicity. Cell wall analysis showed that Al accumulated predominantly in alkali-soluble pectin (pectin 2) of RBCs. This could be attributed to a significant increase of uronic acids under Al toxicity, higher capacity of Al adsorption in pectin 2 [5.3-fold higher than that of chelate-soluble pectin (pectin 1)], and lower ratio of Al desorption from pectin 2 (8.5%) compared with pectin 1 (68.5%). These results indicate that pectin 2 is the primary target of Al immobilization in RBCs of pea, which impairs Al access to the intracellular space of RBCs and mobility to root apices, and therefore protects root apices and RBCs from Al toxicity.

  18. Alkali-Soluble Pectin Is the Primary Target of Aluminum Immobilization in Root Border Cells of Pea (Pisum sativum)

    PubMed Central

    Yang, Jin; Qu, Mei; Fang, Jing; Shen, Ren Fang; Feng, Ying Ming; Liu, Jia You; Bian, Jian Feng; Wu, Li Shu; He, Yong Ming; Yu, Min

    2016-01-01

    We investigated the hypothesis that a discrepancy of Al binding in cell wall constituents determines Al mobility in root border cells (RBCs) of pea (Pisum sativum), which provides protection for RBCs and root apices under Al toxicity. Plants of pea (P. sativum L. ‘Zhongwan no. 6’) were subjected to Al treatments under mist culture. The concentration of Al in RBCs was much higher than that in the root apex. The Al content in RBCs surrounding one root apex (104 RBCs) was approximately 24.5% of the total Al in the root apex (0–2.5 mm), indicating a shielding role of RBCs for the root apex under Al toxicity. Cell wall analysis showed that Al accumulated predominantly in alkali-soluble pectin (pectin 2) of RBCs. This could be attributed to a significant increase of uronic acids under Al toxicity, higher capacity of Al adsorption in pectin 2 [5.3-fold higher than that of chelate-soluble pectin (pectin 1)], and lower ratio of Al desorption from pectin 2 (8.5%) compared with pectin 1 (68.5%). These results indicate that pectin 2 is the primary target of Al immobilization in RBCs of pea, which impairs Al access to the intracellular space of RBCs and mobility to root apices, and therefore protects root apices and RBCs from Al toxicity. PMID:27679639

  19. Alkali-Soluble Pectin Is the Primary Target of Aluminum Immobilization in Root Border Cells of Pea (Pisum sativum).

    PubMed

    Yang, Jin; Qu, Mei; Fang, Jing; Shen, Ren Fang; Feng, Ying Ming; Liu, Jia You; Bian, Jian Feng; Wu, Li Shu; He, Yong Ming; Yu, Min

    2016-01-01

    We investigated the hypothesis that a discrepancy of Al binding in cell wall constituents determines Al mobility in root border cells (RBCs) of pea (Pisum sativum), which provides protection for RBCs and root apices under Al toxicity. Plants of pea (P. sativum L. 'Zhongwan no. 6') were subjected to Al treatments under mist culture. The concentration of Al in RBCs was much higher than that in the root apex. The Al content in RBCs surrounding one root apex (10(4) RBCs) was approximately 24.5% of the total Al in the root apex (0-2.5 mm), indicating a shielding role of RBCs for the root apex under Al toxicity. Cell wall analysis showed that Al accumulated predominantly in alkali-soluble pectin (pectin 2) of RBCs. This could be attributed to a significant increase of uronic acids under Al toxicity, higher capacity of Al adsorption in pectin 2 [5.3-fold higher than that of chelate-soluble pectin (pectin 1)], and lower ratio of Al desorption from pectin 2 (8.5%) compared with pectin 1 (68.5%). These results indicate that pectin 2 is the primary target of Al immobilization in RBCs of pea, which impairs Al access to the intracellular space of RBCs and mobility to root apices, and therefore protects root apices and RBCs from Al toxicity. PMID:27679639

  20. Alkali-Soluble Pectin Is the Primary Target of Aluminum Immobilization in Root Border Cells of Pea (Pisum sativum)

    PubMed Central

    Yang, Jin; Qu, Mei; Fang, Jing; Shen, Ren Fang; Feng, Ying Ming; Liu, Jia You; Bian, Jian Feng; Wu, Li Shu; He, Yong Ming; Yu, Min

    2016-01-01

    We investigated the hypothesis that a discrepancy of Al binding in cell wall constituents determines Al mobility in root border cells (RBCs) of pea (Pisum sativum), which provides protection for RBCs and root apices under Al toxicity. Plants of pea (P. sativum L. ‘Zhongwan no. 6’) were subjected to Al treatments under mist culture. The concentration of Al in RBCs was much higher than that in the root apex. The Al content in RBCs surrounding one root apex (104 RBCs) was approximately 24.5% of the total Al in the root apex (0–2.5 mm), indicating a shielding role of RBCs for the root apex under Al toxicity. Cell wall analysis showed that Al accumulated predominantly in alkali-soluble pectin (pectin 2) of RBCs. This could be attributed to a significant increase of uronic acids under Al toxicity, higher capacity of Al adsorption in pectin 2 [5.3-fold higher than that of chelate-soluble pectin (pectin 1)], and lower ratio of Al desorption from pectin 2 (8.5%) compared with pectin 1 (68.5%). These results indicate that pectin 2 is the primary target of Al immobilization in RBCs of pea, which impairs Al access to the intracellular space of RBCs and mobility to root apices, and therefore protects root apices and RBCs from Al toxicity.

  1. Membrane Purification Cell for Aluminum Recycling

    SciTech Connect

    David DeYoung; James Wiswall; Cong Wang

    2011-11-29

    Recycling mixed aluminum scrap usually requires adding primary aluminum to the scrap stream as a diluent to reduce the concentration of non-aluminum constituents used in aluminum alloys. Since primary aluminum production requires approximately 10 times more energy than melting scrap, the bulk of the energy and carbon dioxide emissions for recycling are associated with using primary aluminum as a diluent. Eliminating the need for using primary aluminum as a diluent would dramatically reduce energy requirements, decrease carbon dioxide emissions, and increase scrap utilization in recycling. Electrorefining can be used to extract pure aluminum from mixed scrap. Some example applications include producing primary grade aluminum from specific scrap streams such as consumer packaging and mixed alloy saw chips, and recycling multi-alloy products such as brazing sheet. Electrorefining can also be used to extract valuable alloying elements such as Li from Al-Li mixed scrap. This project was aimed at developing an electrorefining process for purifying aluminum to reduce energy consumption and emissions by 75% compared to conventional technology. An electrolytic molten aluminum purification process, utilizing a horizontal membrane cell anode, was designed, constructed, operated and validated. The electrorefining technology could also be used to produce ultra-high purity aluminum for advanced materials applications. The technical objectives for this project were to: - Validate the membrane cell concept with a lab-scale electrorefining cell; - Determine if previously identified voltage increase issue for chloride electrolytes holds for a fluoride-based electrolyte system; - Assess the probability that voltage change issues can be solved; and - Conduct a market and economic analysis to assess commercial feasibility. The process was tested using three different binary alloy compositions (Al-2.0 wt.% Cu, Al-4.7 wt.% Si, Al-0.6 wt.% Fe) and a brazing sheet scrap composition (Al-2

  2. Alterations in the Cytoskeleton Accompany Aluminum-Induced Growth Inhibition and Morphological Changes in Primary Roots of Maize1

    PubMed Central

    Blancaflor, Elison B.; Jones, David L.; Gilroy, Simon

    1998-01-01

    Although Al is one of the major factors limiting crop production, the mechanisms of toxicity remain unknown. The growth inhibition and swelling of roots associated with Al exposure suggest that the cytoskeleton may be a target of Al toxicity. Using indirect immunofluorescence microscopy, microtubules and microfilaments in maize (Zea mays L.) roots were visualized and changes in their organization and stability correlated with the symptoms of Al toxicity. Growth studies showed that the site of Al toxicity was associated with the elongation zone. Within this region, Al resulted in a reorganization of microtubules in the inner cortex. However, the orientation of microtubules in the outer cortex and epidermis remained unchanged even after chronic symptoms of toxicity were manifest. Auxin-induced reorientation and cold-induced depolymerization of microtubules in the outer cortex were blocked by Al pretreatment. These results suggest that Al increased the stability of microtubules in these cells. The stabilizing effect of Al in the outer cortex coincided with growth inhibition. Reoriented microfilaments were also observed in Al-treated roots, and Al pretreatment minimized cytochalasin B-induced microfilament fragmentation. These data show that reorganization and stabilization of the cytoskeleton are closely associated with Al toxicity in maize roots. PMID:9733535

  3. The role of primary 16O as a neutron poison in AGB stars and fluorine primary production at halo metallicities.

    NASA Astrophysics Data System (ADS)

    Gallino, R.; Bisterzo, S.; Cristallo, S.; Straniero, O.

    The discovery of a historical bug in the s-post-process AGB code obtained so far by the Torino group forced us to reconsider the role of primary 16O in the 13C-pocket, produced by the 13C(alpha , n)16O reaction, as important neutron poison for the build up of the s-elements at Halo metallicities. The effect is noticeable only for the highest 13C-pocket efficiencies (cases ST*2 and ST). For Galactic disc metallicities, the bug effect is negligible. A comparative analysis of the neutron poison effect of other primary isotopes (12C, 22Ne and its progenies) is presented. The effect of proton captures, by 14N(n, p)14C, boosts a primary production of fluorine in halo AGB stars, with [F/Fe] comparable to [C/Fe], without affecting the s-elements production.

  4. Examination of silicate limitation of primary production in Jiaozhou Bay, China. I. Silicate being a limiting factor of phytoplankton primary production

    NASA Astrophysics Data System (ADS)

    Yang, Dong-Fang; Zhang, Jing; Lu, Ji-Bin; Gao, Zhen-Hui; Chen, Yu

    2002-09-01

    Jiaozhou Bay data collected from May 1991 to February 1994, in 12 seasonal investigations, and provided the authors by the Ecological Station of Jiaozhou Bay, were analyzed to determine the spatiotemporal variations in temperature, light, nutrients (NO{3/-}-N, NO{2/-}-N, NH{4/+}-N, SiO{3/2-}-Si, PO{4/3-}-P), phytoplankton, and primary production in Jiaozhou Bay. The results indicated that only silicate correlated well in time and space with, and had important effects on, the characteristics, dynamic cycles and trends of, primary production in Jiaozhou Bay. The authors developed a corresponding dynamic model of primary production and silicate and water temperature. Eq. (1) of the model shows that the primary production variation is controlled by the nutrient Si and affected by water temperature; that the main factor controlling the primary production is Si; that water temperature affects the composition of the structure of phytoplankton assemblage; that the different populations of the phytoplankton assemblage occupy different ecological niches for C, the apparent ratio of conversion of silicate in seawater into phytoplankton biomas and D, the coefficient of water temperature's effect on phytoplankton biomass. The authors researched the silicon source of Jiaozhou Bay, the biogeochemical sediment process of the silicon, the phytoplankton predominant species and the phytoplankton structure. The authors considered silicate a limiting factor of primary production in Jiaozhou Bay, whose decreasing concentration of silicate from terrestrial source is supposedly due to dilution by current and uptake by phytoplankton; quantified the silicate assimilated by phytoplankton, the intrinsic ratio of conversion of silicon into phytoplankton biomass, the proportion of silicate uptaken by phytoplankton and diluted by current; and found that the primary production of the phytoplankton is determined by the quantity of the silicate assimilated by them. The phenomenon of apparently high

  5. Method of production of pure hydrogen near room temperature from aluminum-based hydride materials

    DOEpatents

    Pecharsky, Vitalij K.; Balema, Viktor P.

    2004-08-10

    The present invention provides a cost-effective method of producing pure hydrogen gas from hydride-based solid materials. The hydride-based solid material is mechanically processed in the presence of a catalyst to obtain pure gaseous hydrogen. Unlike previous methods, hydrogen may be obtained from the solid material without heating, and without the addition of a solvent during processing. The described method of hydrogen production is useful for energy conversion and production technologies that consume pure gaseous hydrogen as a fuel.

  6. Aluminum migration and chemical weathering in subalpine and alpine soils and tills, Mt. Moosilauke, New Hampshire: the effects of acid rain

    SciTech Connect

    Parnell, R.A.

    1982-01-01

    Aluminum mobilization in response to acidification by precipitation has been described by three methods: (1) observation of existing and relict soil weathering products, particularly clay minerals, (2) measurement of soil solution and low-order stream chemistry, and (3) quantification of the distribution, amount, and dissolution rate of labile soil aluminum. From the latter two methods, the amount and rate of aluminum leaching is predicted. Six labile aluminum reservoirs are, in order of decreasing solubility: (1) inorganic and organic exchangeable aluminum, (2) organo-aluminum complexes, (3) amorphous aluminum trihydroxide, (4) hydroxy-aluminum interlayers in vermiculitic clay minerals, (5) clay mineral lattices and (6) primary aluminosilicates. Progressive acid dissolution (P.A.D.) analysis reveals that only the first four reservoirs yield significant amounts of soluble aluminum and have kinetically distinct solubilities. The relative abundance of the different Al reservoirs depends on exposure, slope, drainage, and depth in the profile. From soil solution data and P.A.D. studies, yearly aluminum losses from soil reservoirs are calculated. At present rainfall acidity levels, the best estimates of the lifespan of these soil aluminum-pH buffers fall between 170 and 840 years. The rate of depletion of soil aluminum is orders of magnitude greater than the rate at which bedrock weathering can replace it.

  7. Aluminum induces neurodegeneration and its toxicity arises from increased iron accumulation and reactive oxygen species (ROS) production.

    PubMed

    Wu, Zhihao; Du, Yumei; Xue, Hua; Wu, Yongsheng; Zhou, Bing

    2012-01-01

    The neurotoxicity of aluminum (Al) - the most abundant metal element on earth - has been known for years. However, the mechanism of Al-induced neurodegeneration and its relationship to Alzheimer's disease are still controversial. In particular, in vivo functional data are lacking. In a Drosophila model with chronic dietary Al overloading, general neurodegeneration and several behavioral changes were observed. Al-induced neurodegeneration is independent of β-amyloid or tau-associated toxicity, suggesting they act in different molecular pathways. Interestingly, Drosophila frataxin (dfh), which causes Friedreich's ataxia if mutated in humans, displayed an interacting effect with Al, suggesting Friedreich's ataxia patients might be more susceptible to Al toxicity. Al-treated flies accumulated large amount of iron and reactive oxygen species (ROS), and exhibited elevated SOD2 activity. Genetic and pharmacological efforts to reduce ROS or chelate excess Fe significantly mitigated Al toxicity. Our results indicate that Al toxicity is mediated through ROS production and iron accumulation and suggest a remedial route to reduce toxicity due to Al exposure.

  8. The Aluminum Smelting Process and Innovative Alternative Technologies

    PubMed Central

    Drabløs, Per Arne

    2014-01-01

    Objective: The industrial aluminum production process is addressed. The purpose is to give a short but comprehensive description of the electrolysis cell technology, the raw materials used, and the health and safety relevance of the process. Methods: This article is based on a study of the extensive chemical and medical literature on primary aluminum production. Results: At present, there are two main technological challenges for the process—to reduce energy consumption and to mitigate greenhouse gas emissions. A future step may be carbon dioxide gas capture and sequestration related to the electric power generation from fossil sources. Conclusions: Workers' health and safety have now become an integrated part of the aluminum business. Work-related injuries and illnesses are preventable, and the ultimate goal to eliminate accidents with lost-time injuries may hopefully be approached in the future. PMID:24806723

  9. Elevation of arginine decarboxylase-dependent putrescine production enhances aluminum tolerance by decreasing aluminum retention in root cell walls of wheat.

    PubMed

    Yu, Yan; Jin, Chongwei; Sun, Chengliang; Wang, Jinghong; Ye, Yiquan; Lu, Lingli; Lin, Xianyong

    2015-12-15

    Aluminum (Al) stress induces putrescine (Put) accumulation in several plants and this response is proposed to alleviate Al toxicity. However, the mechanisms underlying this alleviation remain largely unknown. Here, we show that exposure to Al clearly increases Put accumulation in the roots of wheat plants (Triticum aestivum L. 'Xi Aimai-1') and that this was accompanied by significant increase in the activity of arginine decarboxylase (ADC), a Put producing enzyme. Application of an ADC inhibitor (d-arginine) terminated the Al-induced Put accumulation, indicating that increased ADC activity may be responsible for the increase in Put accumulation in response to Al. The d-arginine treatment also increased the Al-induced accumulation of cell wall polysaccharides and the degree of pectin demethylation in wheat roots. Thus, it elevated Al retention in cell walls and exacerbated Al accumulation in roots, both of which aggravate Al toxicity in wheat plants. The opposite effects were true for exogenous Put application. These results suggest that ADC-dependent Put accumulation plays important roles in providing protection against Al toxicity in wheat plants through decreasing cell wall polysaccharides and increasing the degree of pectin methylation, thus decreasing Al retention in the cell walls.

  10. An Exploration of Behavioral Health Productivity and Billing Practices Within Pediatric Primary Care

    PubMed Central

    Ellens, Rebecca E. H.; Burrell, Katherine M.; Perry, Danika S.; Rafiq, Fatima

    2016-01-01

    Objectives To provide descriptive information on behavioral health (BH) productivity and billing practices within a pediatric primary care setting. Methods This retrospective investigation reviewed 30 months of electronic medical records and financial data. Results The percent of BH provider time spent in direct patient care (productivity) was 35.28% overall, with a slightly higher quarterly average (M  =  36.42%; SD  =  6.46%). In the 646.75 hr BH providers spent in the primary care setting, $52,050.00 was charged for BH services delivered ($80.48 hourly average). Conclusions BH productivity and billing within pediatric primary care were suboptimal and likely multifactorially derived. To promote integrated primary care sustainability, the authors recommend three future aims: improve BH productivity, demonstrate the value-added contributions of BH services within primary care, and advocate for BH-supporting health care reform. PMID:27498983

  11. The Impact of Submesoscale Physics on Primary Productivity of Plankton

    NASA Astrophysics Data System (ADS)

    Mahadevan, Amala

    2016-01-01

    Life in the ocean relies on the photosynthetic production of phytoplankton, which is influenced by the availability of light and nutrients that are modulated by a host of physical processes. Submesoscale processes are particularly relevant to phytoplankton productivity because the timescales on which they act are similar to those of phytoplankton growth. Their dynamics are associated with strong vorticity and strain rates that occur on lateral scales of 0.1-10 km. They can support vertical velocities as large as 100 m d-1 and play a crucial role in transporting nutrients into the sunlit ocean for phytoplankton production. In regimes with deep surface mixed layers, submesoscale instabilities can cause stratification within days, thereby increasing light exposure for phytoplankton trapped close to the surface. These instabilities help to create and maintain localized environments that favor the growth of phytoplankton, contribute to productivity, and cause enormous heterogeneity in the abundance of phytoplankton, which has implications for interactions within the ecosystem.

  12. The Impact of Submesoscale Physics on Primary Productivity of Plankton.

    PubMed

    Mahadevan, Amala

    2016-01-01

    Life in the ocean relies on the photosynthetic production of phytoplankton, which is influenced by the availability of light and nutrients that are modulated by a host of physical processes. Submesoscale processes are particularly relevant to phytoplankton productivity because the timescales on which they act are similar to those of phytoplankton growth. Their dynamics are associated with strong vorticity and strain rates that occur on lateral scales of 0.1-10 km. They can support vertical velocities as large as 100 m d(-1) and play a crucial role in transporting nutrients into the sunlit ocean for phytoplankton production. In regimes with deep surface mixed layers, submesoscale instabilities can cause stratification within days, thereby increasing light exposure for phytoplankton trapped close to the surface. These instabilities help to create and maintain localized environments that favor the growth of phytoplankton, contribute to productivity, and cause enormous heterogeneity in the abundance of phytoplankton, which has implications for interactions within the ecosystem.

  13. Extraction processes for the production of aluminum, titanium, iron, magnesium, and oxygen and nonterrestrial sources

    NASA Technical Reports Server (NTRS)

    Rao, D. B.; Choudary, U. V.; Erstfeld, T. E.; Williams, R. J.; Chang, Y. A.

    1979-01-01

    The suitability of existing terrestrial extractive metallurgical processes for the production of Al, Ti, Fe, Mg, and O2 from nonterrestrial resources is examined from both thermodynamic and kinetic points of view. Carbochlorination of lunar anorthite concentrate in conjunction with Alcoa electrolysis process for Al; carbochlorination of lunar ilmenite concentrate followed by Ca reduction of TiO2; and subsequent reduction of Fe2O3 by H2 for Ti and Fe, respectively, are suggested. Silicothermic reduction of olivine concentrate was found to be attractive for the extraction of Mg becaue of the technological knowhow of the process. Aluminothermic reduction of olivine is the other possible alternative for the production of magnesium. The large quantities of carbon monoxide generated in the metal extraction processes can be used to recover carbon and oxygen by a combination of the following methods: (1) simple disproportionation of CO,(2) methanation of CO and electrolysis of H2O, and (3) solid-state electrolysis of gas mixtures containing CO, CO2, and H2O. The research needed for the adoption of earth-based extraction processes for lunar and asteroidal minerals is outlined.

  14. Aluminum Analysis.

    ERIC Educational Resources Information Center

    Sumrall, William J.

    1998-01-01

    Presents three problems based on the price of aluminum designed to encourage students to be cooperative and to use an investigative approach to learning. Students collect and synthesize information, analyze results, and draw conclusions. (AIM)

  15. The Nondestructive Determination of the Aluminum Content in Pressed Skulls of Aluminum Dross

    NASA Astrophysics Data System (ADS)

    Kevorkijan, Varuzan; Škapin, Srečo Davor; Kovačec, Uroš

    2013-02-01

    During production of primary and secondary aluminum, various amounts (in some cases up to 200 kg) of aluminum dross, a mixture consisting of molten aluminum metal and different oxide compounds (the nonmetallic phase), are skimmed per tonne of molten metal. To preserve the maximum aluminum content in hot dross for further extraction, it is necessary to cool the dross immediately after skimming. One way to do this is to press the skimmed hot dross in a press. In this process, the skimmed dross is transformed into so-called pressed skulls, with characteristic geometry convenient for storage, transport, or further in-house processing. Because of its high aluminum content—usually between 30% and 70%—pressed skulls represent a valuable source of aluminum and hence are in great demand in the aluminum recycling industry. Because pressed skulls are generally valued on a free-metal recovery basis, which is influenced by the yield of recovery, or in other words, by the quality of the recycling process, it was recognized as important and useful to develop a method of fast and cost-effective nondestructive measurement of the free aluminum content in pressed skulls, independent of the technology of pressed skulls recycling. In the model developed in this work, the aluminum content in pressed skulls was expressed as a function of the pressed skulls density, the density of the nonmetallic phase, and the volume fraction of closed pores. In addition, the model demonstrated that under precisely defined conditions (i.e., skulls from the dross of the same aluminum alloy and skimmed, transported, cooled, and pressed in the same way and under the same processing conditions), when other parameters except the pressed skulls density remain constant, the aluminum content in pressed skulls can be expressed as a linear function of the pressed skulls density. Following the theoretical considerations presented in this work, a practical industrial methodology was developed for nondestructive

  16. Influence of Submarine Groundwater Discharge on Primary Productivity in the Semi-Enclosed Bay in Japan

    NASA Astrophysics Data System (ADS)

    Sugimoto, R.; Nishi, S.; Taniguchi, M.; Tominaga, O.

    2014-12-01

    In recent years, a number of studies have shown that submarine groundwater discharge is an alternative nutrient pathway and can drive primary production in coastal seas. However, very little is known about an exact relationship between input of groundwater and response of primary production. To clarify the relationship, we conducted the field survey in the semi-enclosed coastal bay in Japan (Obama Bay). There are abundant amounts of groundwater resources in the basin. Firstly, we conducted 222Rn continuous measurement along the coast in March 2013 to obtain the spatial difference of groundwater impact. As a result, 222Rn activity clearly showed that groundwater discharge concentrates in the western part of the bay head. We thus conducted in-situ measurements of primary productivity using stable 13C tracer method and environmental parameters (ex. 222Rn activity, light intensity, temperature and nutrient concentrations) at 6 stations within the western bay head in July and August 2013. Primary productivity within the western bay head changed from 11.0 to 49.5 μg C L-1 hr-1 in July and from 9.3 to 32.4 μg C L-1 hr-1 in August. Moreover, there was significant relationship between primary productivity and 222Rn concentration in both months. Although light intensity and water temperature were different in each station and month, concentrations of nutrients limited primary productivity. These results showed that nutrient supply from SGD would affect crucial impact on primary productivity in Obama Bay.

  17. Interannual Variation in Phytoplankton Class-Specific Primary Production at a Global Scale

    NASA Technical Reports Server (NTRS)

    Rousseaux, Cecile Severine; Gregg, Watson W.

    2014-01-01

    We used the NASA Ocean Biogeochemical Model (NOBM) combined with remote sensing data via assimilation to evaluate the contribution of 4 phytoplankton groups to the total primary production. First we assessed the contribution of each phytoplankton groups to the total primary production at a global scale for the period 1998-2011. Globally, diatoms were the group that contributed the most to the total phytoplankton production (50, the equivalent of 20 PgC y-1. Coccolithophores and chlorophytes each contributed to 20 (7 PgC y-1 of the total primary production and cyanobacteria represented about 10 (4 PgC y(sub-1) of the total primary production. Primary production by diatoms was highest in high latitude (45) and in major upwelling systems (Equatorial Pacific and Benguela system). We then assessed interannual variability of this group-specific primary production over the period 1998-2011. Globally the annual relative contribution of each phytoplankton groups to the total primary production varied by maximum 4 (1-2 PgC y-1. We assessed the effects of climate variability on the class-specific primary production using global (i.e. Multivariate El Nio Index, MEI) and regional climate indices (e.g. Southern Annular Mode (SAM), Pacific Decadal Oscillation (PDO) and North Atlantic Oscillation (NAO)). Most interannual variability occurred in the Equatorial Pacific and was associated with climate variability as indicated by significant correlation (p 0.05) between the MEI and the class-specific primary production from all groups except coccolithophores. In the Atlantic, climate variability as indicated by NAO was significantly correlated to the primary production of 2 out of the 4 groups in the North Central Atlantic (diatomscyanobacteria) and in the North Atlantic (chlorophytes and coccolithophores). We found that climate variability as indicated by SAM had only a limited effect on the class-specific primary production in the Southern Ocean. These results provide a modeling and

  18. Production of a novel bioflocculant and its flocculation performance in aluminum removal.

    PubMed

    Li, Lixin; Ma, Fang; Zuo, Huimin

    2016-04-01

    A novel bioflocculant CBF with high flocculating activity, produced by mixed culture of Rhizobium radiobacter F2 and Bacillus sphaericus F6 from soil, was investigated with regard to its production and flocculation performance in Al(III) removal. The most preferred carbon source, nitrogen source and C/N ratio (w/w) for strains F2 and F6 to produce CBF were glucose, urea and 20, respectively. The optimal inoculum size for CBF production was 10 % (v/v). The optimal initial pH, culture temperature and shaking speed were 7-8, 30°C and 140 r/min for 24 h, respectively, under which the flocculating activity of the bioflocculant reached 98.52 %. According to literature review, flocculant dosage, coagulant aid dosage, pH, hydraulic condition of coagulation and sedimentation time are considered as influencing parameters for CBF flocculation performance in Al(III) removal by L16(4(5)) orthogonal design. The optimal conditions for Al(III) removal obtained through analysis and verification experiments were as follows: CBF, 28 mg/L; coagulant aid, 1.5 mL/L; initial pH, 8.0; and hydraulic conditions of coagulation: stir speed, 160 r/min; stir time, 40 s; and sedimentation time, 30 min. Under the optimal conditions, the removal efficiency of Al(III) was 92.95 %. Overall, these findings indicate that bioflocculant CBF offers an effective alternative method of decreasing Al(III) during drinking water treatment. PMID:27002778

  19. Production of a novel bioflocculant and its flocculation performance in aluminum removal.

    PubMed

    Li, Lixin; Ma, Fang; Zuo, Huimin

    2016-04-01

    A novel bioflocculant CBF with high flocculating activity, produced by mixed culture of Rhizobium radiobacter F2 and Bacillus sphaericus F6 from soil, was investigated with regard to its production and flocculation performance in Al(III) removal. The most preferred carbon source, nitrogen source and C/N ratio (w/w) for strains F2 and F6 to produce CBF were glucose, urea and 20, respectively. The optimal inoculum size for CBF production was 10 % (v/v). The optimal initial pH, culture temperature and shaking speed were 7-8, 30°C and 140 r/min for 24 h, respectively, under which the flocculating activity of the bioflocculant reached 98.52 %. According to literature review, flocculant dosage, coagulant aid dosage, pH, hydraulic condition of coagulation and sedimentation time are considered as influencing parameters for CBF flocculation performance in Al(III) removal by L16(4(5)) orthogonal design. The optimal conditions for Al(III) removal obtained through analysis and verification experiments were as follows: CBF, 28 mg/L; coagulant aid, 1.5 mL/L; initial pH, 8.0; and hydraulic conditions of coagulation: stir speed, 160 r/min; stir time, 40 s; and sedimentation time, 30 min. Under the optimal conditions, the removal efficiency of Al(III) was 92.95 %. Overall, these findings indicate that bioflocculant CBF offers an effective alternative method of decreasing Al(III) during drinking water treatment.

  20. Energy release properties of amorphous boron and boron-based propellant primary combustion products

    NASA Astrophysics Data System (ADS)

    Liang, Daolun; Liu, Jianzhong; Xiao, Jinwu; Xi, Jianfei; Wang, Yang; Zhang, Yanwei; Zhou, Junhu

    2015-07-01

    The microstructure of amorphous boron and the primary combustion products of boron-based fuel-rich propellant (hereafter referred to as primary combustion products) was analyzed by scanning electron microscope. Composition analysis of the primary combustion products was carried out by X-ray diffraction and X-ray photoelectron spectroscopy. The energy release properties of amorphous boron and the primary combustion products were comparatively studied by laser ignition experimental system and thermogravimetry-differential scanning calorimetry. The primary combustion products contain B, C, Mg, Al, B4C, B13C2, BN, B2O3, NH4Cl, H2O, and so on. The energy release properties of primary combustion products are different from amorphous boron, significantly. The full-time spectral intensity of primary combustion products at a wavelength of 580 nm is ~2% lower than that of amorphous boron. The maximum spectral intensity of the former at full wave is ~5% higher than that of the latter. The ignition delay time of primary combustion products is ~150 ms shorter than that of amorphous boron, and the self-sustaining combustion time of the former is ~200 ms longer than that of the latter. The thermal oxidation process of amorphous boron involves water evaporation (weight loss) and boron oxidation (weight gain). The thermal oxidation process of primary combustion products involves two additional steps: NH4Cl decomposition (weight loss) and carbon oxidation (weight loss). CL-20 shows better combustion-supporting effect than KClO4 in both the laser ignition experiments and the thermal oxidation experiments.

  1. Primary production and canopy cover in bitterbrush-cheatgrass communities

    SciTech Connect

    Rickard, W.H.; Sauer, R.H.

    1982-01-01

    Aboveground grass and forb production averaged 126 g m/sup -2/ yr/sup -1/ and ranged between 10 and 195 grams over a four year period 1975-1978. The low production year was 1977, a year of extreme drought. Production was not significantly different between unburned sites and burned sites five years post burning (1970). Canopy cover and species composition were similar on burned and unburned sites except for the shrubs, bitterbrush (Purshia tridentata) and sagebrush (Artemisia tridentata), which were killed by burning. There was no indication that shrubs were invading the burned areas as seedlings or vegetatively through sprouting. The implications of burning and mule deer (Odocoileus hemionus) management are briefly discussed.

  2. Interannual Variation in Phytoplankton Class-specific Primary Production at a Global Scale

    NASA Technical Reports Server (NTRS)

    Rousseaux, Cecile; Gregg, Watson

    2014-01-01

    Phytoplankton is responsible for over half of the net primary production on earth. The knowledge on the contribution of various phytoplankton groups to the total primary production is still poorly understood. Data from satellite observations suggest that for upwelling regions, photosynthetic rates by microplankton is higher than that of nanoplankton but that when the spatial extent is considered, the production by nanoplankton is comparable or even larger than microplankton. Here, we used the NASA Ocean Biogeochemical Model (NOBM) combined with remote sensing data via assimilation to evaluate the contribution of 4 phytoplankton groups to the total primary production. Globally, diatoms were the group that contributed the most to the total phytoplankton production (approx. 50%) followed by coccolithophores and chlorophytes. Primary production by diatoms was highest in high latitude (>45 deg) and in major upwelling systems (Equatorial Pacific and Benguela system). We assessed the effects of climate variability on the class-specific primary production using global (i.e. Multivariate El Nino Index, MEI) and 'regional' climate indices (e.g. Southern Annular Mode (SAM), Pacific Decadal Oscillation (PDO) and North Atlantic Oscillation (NAO)). Most interannual variability occurred in the Equatorial Pacific and was associated with climate variability. These results provide a modeling and data assimilation perspective to phytoplankton partitioning of primary production and contribute to our understanding of the dynamics of the carbon cycle in the oceans at a global scale.

  3. Transformation products of submicron-sized aluminum-substituted magnetite: Color and reductant solubility

    NASA Technical Reports Server (NTRS)

    Golden, D. C.; Ming, D. W.; Lauer, H. V., Jr.

    1991-01-01

    Magnetite, when present as fine particles, is soluble in acid ammonium oxalate (pH equals 3). However, the commonly used extractant for free iron oxides (i.e., citrate dithionite-bicarbonate (CDB) is not very effective in dissolving magnetite in soils and geologic materials. Upon oxidation, magnetite transforms to maghemite; at elevated temperatures, maghemite inverts to hematite. This transformation causes a change in color from black to red and may affect the reductant solubility as well. The objectives here were to examine the color and reflectance spectral characteristics of products during the transformation of magnetite to maghemite to hematite and to study the effect of Al-substitution in magnetite on the above process. Reductant solubility of Al-substituted magnetite, maghemite, and hematite was also studied. In summary, the transformation of magnetite to maghemite was accompanied by a change in color from black to red because of the oxidation of Fe2(+) to Fe3(+). The phase change maghemite to hematite had a relatively minor effect on the color and the reflectance spectra.

  4. Fission Product Migration in Primary System and Containment

    SciTech Connect

    2015-04-01

    Version 00 ART MOD2 aims at a comprehensive analysis for the FP behaviour in primary system and in containment during severe accidents and therefore the code considers the removal of radio-nuclides of up to 60 materials including chemical compounds by natural deposition and by the engineered safety features (ESF) such as spray systems. As for the natural deposition of radio-nuclides, the code can consider the phenomena such as gravitational settling, thermophoresis, diffusiophoresis, Brownian diffusion, diffusion under laminar or turbulent flows, resuspension, condensation, chemisorption and revaporization. The code also models the aerosol growth by agglomeration of aerosols and condensation/evaporation of volatile material at the aerosol surface. Recently, the models for iodine chemistry in containment sump water was incorporated into ART MOD2 ART MOD2 was modified in January 2015 to correct coding errors and improve the vibration of the calculation result of water (H2O) vapor.

  5. Lentiviral vector production, titration, and transduction of primary neurons.

    PubMed

    Ding, Baojin; Kilpatrick, Daniel L

    2013-01-01

    Lentiviral vectors have become very useful tools for transgene delivery. Based on their ability to transduce both dividing and nondividing cells and to produce long-term transgene expression, lentiviruses have found numerous applications in the biomedical sciences, including developmental neuroscience. This protocol describes how to prepare lentiviral vectors by calcium phosphate transfection and to concentrate viral particles by ultracentrifugation. Functional vector titers can then be determined by methods such as fluorescence-activated cell sorting or immunostaining. Effective titers in the range of 10(8)-10(9) infectious units/ml can be routinely obtained using these protocols. Finally, we describe the infection of primary neuronal cultures with lentiviral vectors resulting in 85-90 % cell transduction using appropriate multiplicities of infection.

  6. Zika virus productively infects primary human placenta-specific macrophages

    PubMed Central

    Jurado, Kellie Ann; Simoni, Michael K.; Tang, Zhonghua; Uraki, Ryuta; Hwang, Jesse; Householder, Sarah; Wu, Mingjie; Lindenbach, Brett D.; Abrahams, Vikki M.; Guller, Seth

    2016-01-01

    The strong association of Zika virus infection with congenital defects has led to questions of how a flavivirus is capable of crossing the placental barrier to reach the fetal brain. Here, we demonstrate permissive Zika virus infection of primary human placental macrophages, commonly referred to as Hofbauer cells, and placental villous fibroblasts. We also demonstrate Zika virus infection of Hofbauer cells within the context of the tissue ex vivo using term placental villous explants. In addition to amplifying infectious virus within a usually inaccessible area, the putative migratory activities of Hofbauer cells may aid in dissemination of Zika virus to the fetal brain. Understanding the susceptibility of placenta-specific cell types will aid future work around and understanding of Zika virus–associated pregnancy complications. PMID:27595140

  7. Zika virus productively infects primary human placenta-specific macrophages

    PubMed Central

    Jurado, Kellie Ann; Simoni, Michael K.; Tang, Zhonghua; Uraki, Ryuta; Hwang, Jesse; Householder, Sarah; Wu, Mingjie; Lindenbach, Brett D.; Abrahams, Vikki M.; Guller, Seth; Fikrig, Erol

    2016-01-01

    The strong association of Zika virus infection with congenital defects has led to questions of how a flavivirus is capable of crossing the placental barrier to reach the fetal brain. Here, we demonstrate permissive Zika virus infection of primary human placental macrophages, commonly referred to as Hofbauer cells, and placental villous fibroblasts. We also demonstrate Zika virus infection of Hofbauer cells within the context of the tissue ex vivo using term placental villous explants. In addition to amplifying infectious virus within a usually inaccessible area, the putative migratory activities of Hofbauer cells may aid in dissemination of Zika virus to the fetal brain. Understanding the susceptibility of placenta-specific cell types will aid future work around and understanding of Zika virus–associated pregnancy complications.

  8. Fission Product Migration in Primary System and Containment

    2015-04-01

    Version 00 ART MOD2 aims at a comprehensive analysis for the FP behaviour in primary system and in containment during severe accidents and therefore the code considers the removal of radio-nuclides of up to 60 materials including chemical compounds by natural deposition and by the engineered safety features (ESF) such as spray systems. As for the natural deposition of radio-nuclides, the code can consider the phenomena such as gravitational settling, thermophoresis, diffusiophoresis, Brownian diffusion, diffusionmore » under laminar or turbulent flows, resuspension, condensation, chemisorption and revaporization. The code also models the aerosol growth by agglomeration of aerosols and condensation/evaporation of volatile material at the aerosol surface. Recently, the models for iodine chemistry in containment sump water was incorporated into ART MOD2 ART MOD2 was modified in January 2015 to correct coding errors and improve the vibration of the calculation result of water (H2O) vapor.« less

  9. 21 CFR 182.1125 - Aluminum sulfate.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 3 2013-04-01 2013-04-01 false Aluminum sulfate. 182.1125 Section 182.1125 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) FOOD FOR... Substances § 182.1125 Aluminum sulfate. (a) Product. Aluminum sulfate. (b) Conditions of use. This...

  10. 21 CFR 182.1125 - Aluminum sulfate.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 3 2011-04-01 2011-04-01 false Aluminum sulfate. 182.1125 Section 182.1125 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) FOOD FOR... Substances § 182.1125 Aluminum sulfate. (a) Product. Aluminum sulfate. (b) Conditions of use. This...

  11. 21 CFR 582.1125 - Aluminum sulfate.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 6 2013-04-01 2013-04-01 false Aluminum sulfate. 582.1125 Section 582.1125 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL... Additives § 582.1125 Aluminum sulfate. (a) Product. Aluminum sulfate. (b) Conditions of use. This...

  12. 21 CFR 582.1125 - Aluminum sulfate.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Aluminum sulfate. 582.1125 Section 582.1125 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL... Additives § 582.1125 Aluminum sulfate. (a) Product. Aluminum sulfate. (b) Conditions of use. This...

  13. 21 CFR 582.1125 - Aluminum sulfate.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 6 2012-04-01 2012-04-01 false Aluminum sulfate. 582.1125 Section 582.1125 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL... Additives § 582.1125 Aluminum sulfate. (a) Product. Aluminum sulfate. (b) Conditions of use. This...

  14. 21 CFR 182.1125 - Aluminum sulfate.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Aluminum sulfate. 182.1125 Section 182.1125 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) FOOD FOR... Substances § 182.1125 Aluminum sulfate. (a) Product. Aluminum sulfate. (b) Conditions of use. This...

  15. 21 CFR 582.1125 - Aluminum sulfate.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 6 2014-04-01 2014-04-01 false Aluminum sulfate. 582.1125 Section 582.1125 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL... Additives § 582.1125 Aluminum sulfate. (a) Product. Aluminum sulfate. (b) Conditions of use. This...

  16. 21 CFR 582.1125 - Aluminum sulfate.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 6 2011-04-01 2011-04-01 false Aluminum sulfate. 582.1125 Section 582.1125 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL... Additives § 582.1125 Aluminum sulfate. (a) Product. Aluminum sulfate. (b) Conditions of use. This...

  17. 21 CFR 182.1125 - Aluminum sulfate.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 3 2014-04-01 2014-04-01 false Aluminum sulfate. 182.1125 Section 182.1125 Food... GENERALLY RECOGNIZED AS SAFE Multiple Purpose GRAS Food Substances § 182.1125 Aluminum sulfate. (a) Product. Aluminum sulfate. (b) Conditions of use. This substance is generally recognized as safe when used...

  18. 21 CFR 182.1125 - Aluminum sulfate.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 3 2012-04-01 2012-04-01 false Aluminum sulfate. 182.1125 Section 182.1125 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) FOOD FOR... Substances § 182.1125 Aluminum sulfate. (a) Product. Aluminum sulfate. (b) Conditions of use. This...

  19. (Polyfluoroaryl)fluoroanions of aluminum, gallium, and indium of enhanced utility, uses thereof, and products based thereon

    DOEpatents

    Marks, Tobin J.; Chen, You-Xian

    2001-01-01

    The (polyfluoroaryl)fluoroanions of aluminum, gallium, and indium are novel weakly coordinating anions which are are highly fluorinated. (Polyfluoroaryl)fluoroanions of one such type contain at least one ring substituent other than fluorine. These (polyfluoroaryl)fluoroanions of aluminum, gallium, and indium have greater solubility in organic solvents, or have a coordinative ability essentially equal to or less than that of the corresponding (polyfluoroaryl)fluoroanion of aluminum, gallium, or indium in which the substituent is replaced by fluorine. Another type of new (polyfluoroaryl)fluoroanion of aluminum, gallium, and indium have 1-3 perfluorinated fused ring groups and 2-0 perfluorophenyl groups. When used as a cocatalyst in the formation of novel catalytic complexes with d- or f-block metal compounds having at least one leaving group such as a methyl group, these anions, because of their weak coordination to the metal center, do not interefere in the ethylene polymerization process, while affecting the the propylene process favorably, if highly isotactic polypropylene is desired. Thus, the (polyfluoroaryl)fluoroanions of aluminum, gallium, and indium of this invention are useful in various polymerization processes such as are described.

  20. Comparison of marine productivity among Outer Continental Shelf planning areas. Supplement: An evaluation of benthic habitat primary productivity. Final report

    SciTech Connect

    Balcom, B.J.; Foster, M.A.; Fourqurean, J.J.; Heine, J.N.; Leonard, G.H.

    1991-01-01

    Literature on current primary productivity was reviewed and evaluated for each of nine benthic communities or habitats, estimates of daily and annual benthic primary productivity were derived within each community, the benthic primary estimates were related to an estimate of areal extent of each community within or adjacent to each OCS planning area. Direct comparisons between habitats was difficult because of the varying measures and methodologies used. Coastal marshes were the most prevalent habitat type evaluated. Mangrove and coral reef habitats were highly productive but occur within few planning areas. Benthic diatoms and blue-green algae are less productive in terms of estimated annual productivity on a per square meter basis; these habitats have the potential to occur across wide areas of the OCS and should not be overlooked.

  1. Basin-scale estimates of oceanic primary production by remote sensing: The North Atlantic

    NASA Astrophysics Data System (ADS)

    Platt, Trevor; Caverhill, Carla; Sathyendranath, Shubha

    1991-08-01

    The estimation by remote sensing of annual primary production at ocean basin scales is illustrated for the Atlantic Ocean, using the monthly averaged Coastal Zone Color Scanner data for 1979. The principal supplementary data used were some 873 vertical profiles of chlorophyll and some 248 sets of parameters derived from photosynthesis-light experiments. This information was used to parametrize the local algorithm for calculation of primary production in 12 subregions of the entire domain for each of the four seasons. Four different procedures were tested for calculation of primary production. These differed according to whether the autotrophic biomass distribution was uniform with depth and whether the irradiance was resolved with respect to wavelength: the spectral model with nonuniform biomass was considered as the benchmark for comparison against the other three models. At particular locations and times, the less complete models gave results that differed by as much as 50% from the benchmark. After integration to basin scale, vertically uniform models tended to underestimate primary production by about 20% compared to the nonuniform models. At large horizontal scale, the differences between spectral and nonspectral models were negligible, a result that was believed to follow from mutual compensation of underestimates and overestimates, according to the local biomass, in different parts of the domain. Calculation of primary production is highly sensitive to the algorithm used to retrieve the biomass. The linear correlation between biomass and estimated production was poor outside the tropics, suggesting caution against the indiscriminate use of biomass as a proxy variable for primary production. The annual primary production for the Atlantic between 20°S and 70°N was 9 ± 3 Gt yr-1, higher than previous estimates made without reference to remotely sensed data. It is argued that the remote-sensing method is the method of choice for calculation of primary

  2. Will Global Change Effect Primary Productivity in Coastal Ecosystems?

    NASA Technical Reports Server (NTRS)

    Rothschild, Lynn J.; Peterson, David L. (Technical Monitor)

    1997-01-01

    Algae are the base of coastal food webs because they provide the source of organic carbon for the remaining members of the community. Thus, the rate that they produce organic carbon to a large extent controls the productivity of the entire ecosystem. Factors that control algal productivity range from the physical (e.g., temperature, light), chemical (e.g., nutrient levels) to the biological (e.g., grazing). Currently, levels of atmospheric carbon dioxide surficial fluxes of ultraviolet radiation are rising. Both of these environmental variables can have a profound effect on algal productivity. Atmospheric carbon dioxide may increase surficial levels of dissolved inorganic carbon. Our laboratory and field studies of algal mats and phytoplankton cultures under ambient and elevated levels of pCO2 show that elevated levels of inorganic carbon can cause an increase in photosynthetic rates. In some cases, this increase will cause an increase in phytoplankton numbers. There may be an increase in the excretion of fixed carbon, which in turn may enhance bacterial productivity. Alternatively, in analogy with studies on the effect of elevated pCO2 on plants, the phytoplankton could change their carbon to nitrogen ratios, which will effect the feeding of the planktonic grazers. The seasonal depletion of stratospheric ozone has resulted in elevated fluxes of UVB radiation superimposed on the normal seasonal variation. Present surface UV fluxes have a significant impact on phytoplankton physiology, including the inhibition of the light and dark reactions of photosynthesis, inhibition of nitrogenase activity, inhibition of heterocyst formation, reduction in motility, increased synthesis of the UV-screening pigment scytonemin, and mutation. After reviewing these issues, recent work in our lab on measuring the effect of UV radiation on phytoplankton in the San Francisco Bay Estuary will be presented.

  3. Fast repetition rate (FRR) fluorometer for making in situ measurements of primary productivity

    SciTech Connect

    Kolber, Z.S.; Falkowski, P.G.

    1992-01-01

    Understanding the ocean carbon cycle and predicting how climate-induced changes in ocean circulation will affect ocean productivity requires that (a) primary productivity be measured with high spatial and temporal resolution, and (b) natural variability in primary productivity be parameterized with regardto environmental factors such as nutrient availabuity, irradiance, and temperature. Instrumentation to measure primary productivity from the stimulated in vivo fluoresence of phytoplankton chlorophyll is currendy being developed at Brookhaven National Laboratory. The instrumentation is based on fast repetition rate (FRR) fluorometry, and provides a robust technique for deriving the photosynthetic rates in situ. Moreover, the FRR methodology directly measures several photosynthetic parameters such as effective absorption cross- section, photo-conversion efficiency, and turnover time of photosynthesis, and relate them to primary productivity. Since photosynthetic parameters are affected by environmental factors such as fight and nutrient availability, the relationship between these parameters and primary productivity can be established. By understanding such relationships, prognostic models of primary productivity can be developed and parameterized.

  4. Fast repetition rate (FRR) fluorometer for making in situ measurements of primary productivity

    SciTech Connect

    Kolber, Z.S.; Falkowski, P.G.

    1992-10-01

    Understanding the ocean carbon cycle and predicting how climate-induced changes in ocean circulation will affect ocean productivity requires that (a) primary productivity be measured with high spatial and temporal resolution, and (b) natural variability in primary productivity be parameterized with regardto environmental factors such as nutrient availabuity, irradiance, and temperature. Instrumentation to measure primary productivity from the stimulated in vivo fluoresence of phytoplankton chlorophyll is currendy being developed at Brookhaven National Laboratory. The instrumentation is based on fast repetition rate (FRR) fluorometry, and provides a robust technique for deriving the photosynthetic rates in situ. Moreover, the FRR methodology directly measures several photosynthetic parameters such as effective absorption cross- section, photo-conversion efficiency, and turnover time of photosynthesis, and relate them to primary productivity. Since photosynthetic parameters are affected by environmental factors such as fight and nutrient availability, the relationship between these parameters and primary productivity can be established. By understanding such relationships, prognostic models of primary productivity can be developed and parameterized.

  5. Ecological risks of Aluminum production and contaminated area by red mud in Western Hungary (Ajka)

    NASA Astrophysics Data System (ADS)

    Rasulov, Oqil; Horváth, Adrienn; Bidló, András; Winkler, Dániel

    2016-04-01

    In October 2010, Hungary experienced one of the most severe environmental disasters: the dam wall of a red mud depository of an alumina plant in collapsed and more than 1 million m3 of toxic sludge flooded the surrounding area. Red mud is a strongly alkaline (pH of 9-12.5) by-product due to the high NaOH content. Apart from residual minerals and oxides, its components also include heavy metals such as Cu, Zn, Cd, Hg, Pb, Ni, Co. As it has already been assessed, red mud had considerable effect on soil properties and thus on soil biodiversity. The aim of our study was to determine the aftereffects of red mud pollution on the soil mesofauna (Collembola). Study plots were selected in the area affected by the toxic flood, in agricultural and grassland habitats, at different distances (0.3 to 12.5 km) from the contamination source. Control plots of each habitat types were selected for comparative analyses. Soil samples were taken during the summer of 2015, five years after the red mud disaster. From each of the selected plots, 5 soil cores of 100 cm3 volume (3.6 cm in diameter and 10 cm in depth) were sampled from which springtails were extracted within 14 days using a modified Tullgren apparatus. Simultaneously with the Collembola sampling, we collected soil samples on each plots in order to determine soil properties (pH, CaCO3, particle size distribution) and the degree of heavy metal pollution. 25 heavy metals were measured (including total Hg) following the method of total (cc. HNO3 + H2O2-soluble) and bioavailable (NH4-acetate + EDTA-soluble) element content using ICP-OES and AMA 254. The studied habitats presented neutral to moderately alkaline soils (pH 7.2-8.1). Total metal content was higher in the plots formerly affected by red mud flood. The Hg concentration ranged from 0.023 to 1.167 mg.kg-1, exceeding the threshold concentration (0.5 mg.kg-1) defined by Hungarian legislation for toxic trace metals in soil. The collected 1442 Collembola specimens belong to 32

  6. Microscale Topographic Influence on Grassland Primary Productivity on Semiarid Hillslopes

    NASA Astrophysics Data System (ADS)

    Travis, Jeffrey Todd

    Understanding the distribution of plant productivity is vital for understanding the spatial variability of ecosystem functions. This study evaluates microtopographic controls (1m-12m) on plant productivity on three rolling hills in Sedgwick Natural Reserve, located in south-central California. Specifically I evaluate the relationship between topographic metrics and plant biomass production through space and time. Biomass was measured using destructive harvests and seasonal Airborne Visible Infrared Imaging Spectrometer (AVIRIS) data. Eighty-three 1x0.5m2 quadrats of aboveground plant matter at peak biomass (ANPP) were harvested for the 2012 growing season. For the 2009 growing season, AVIRIS derived Normalized Difference Vegetation Index (NDVI) was used to estimate biomass at roughly monthly intervals from March to August. I evaluate whether seasonal changes in growing degree days (GDD) was a better predictor of plant phenological events than cumulative days since first soil moisture increase. To characterize topography, I used a 1m resolution digital elevation model derived from terrestrial lidar data to calculate curvature, aspect, and the Compound Topographic Index (CTI) - an index that integrates the flow accumulation area and slope. Using GDD, I found that ecosystem productivity was not temperature limited early in the growing season. Using webcam images I was able to remotely monitor phenological events quantitatively, but was not able to calculate NDVI because I lacked appropriate spectral bands. Plants growing on north facing slopes consistently had higher ANPP than those on south facing slopes, due to lower temperatures, hence greater preservation of soil moisture. No correlation was found between CTI or curvature and ANPP across the 83 sampled points in 2012, potentially because it was a dry year and there was limited water redistribution to lower positions in the landscape. Although a relationship between topography and soil moisture is probably valid

  7. Methylmercury bioaccumulation in stream food webs declines with increasing primary production

    USGS Publications Warehouse

    Walters, David; D.F. Raikow,; C.R. Hammerschmidt,; M.G. Mehling,; A. Kovach,; J.T. Oris,

    2015-01-01

    Opposing hypotheses posit that increasing primary productivity should result in either greater or lesser contaminant accumulation in stream food webs. We conducted an experiment to evaluate primary productivity effects on MeHg accumulation in stream consumers. We varied light for 16 artificial streams creating a productivity gradient (oxygen production =0.048–0.71 mg O2 L–1 d–1) among streams. Two-level food webs were established consisting of phytoplankton/filter feeding clam, periphyton/grazing snail, and leaves/shredding amphipod (Hyalella azteca). Phytoplankton and periphyton biomass, along with MeHg removal from the water column, increased significantly with productivity, but MeHg concentrations in these primary producers declined. Methylmercury concentrations in clams and snails also declined with productivity, and consumer concentrations were strongly correlated with MeHg concentrations in primary producers. Heterotroph biomass on leaves, MeHg in leaves, and MeHg in Hyalella were unrelated to stream productivity. Our results support the hypothesis that contaminant bioaccumulation declines with stream primary production via the mechanism of bloom dilution (MeHg burden per cell decreases in algal blooms), extending patterns of contaminant accumulation documented in lakes to lotic systems.

  8. Methylmercury Bioaccumulation in Stream Food Webs Declines with Increasing Primary Production.

    PubMed

    Walters, David M; Raikow, David F; Hammerschmidt, Chad R; Mehling, Molly G; Kovach, Amanda; Oris, James T

    2015-07-01

    Opposing hypotheses posit that increasing primary productivity should result in either greater or lesser contaminant accumulation in stream food webs. We conducted an experiment to evaluate primary productivity effects on MeHg accumulation in stream consumers. We varied light for 16 artificial streams creating a productivity gradient (oxygen production =0.048-0.71 mg O2 L(-1) d(-1)) among streams. Two-level food webs were established consisting of phytoplankton/filter feeding clam, periphyton/grazing snail, and leaves/shredding amphipod (Hyalella azteca). Phytoplankton and periphyton biomass, along with MeHg removal from the water column, increased significantly with productivity, but MeHg concentrations in these primary producers declined. Methylmercury concentrations in clams and snails also declined with productivity, and consumer concentrations were strongly correlated with MeHg concentrations in primary producers. Heterotroph biomass on leaves, MeHg in leaves, and MeHg in Hyalella were unrelated to stream productivity. Our results support the hypothesis that contaminant bioaccumulation declines with stream primary production via the mechanism of bloom dilution (MeHg burden per cell decreases in algal blooms), extending patterns of contaminant accumulation documented in lakes to lotic systems.

  9. Effects of oligotrophication on primary production in peri-alpine lakes

    NASA Astrophysics Data System (ADS)

    Finger, David; Wüest, Alfred; Bossard, Peter

    2013-08-01

    During the second half of the 20th century untreated sewage released from housing and industry into natural waters led to a degradation of many freshwater lakes and reservoirs worldwide. In order to mitigate eutrophication, wastewater treatment plants, including Fe-induced phosphorus precipitation, were implemented throughout the industrialized world, leading to reoligotrophication in many freshwater lakes. To understand and assess the effects of reoligotrophication on primary productivity, we analyzed 28 years of 14C assimilation rates, as well as other biotic and abiotic parameters, such as global radiation, nutrient concentrations and plankton densities in peri-alpine Lake Lucerne, Switzerland. Using a simple productivity-light relationship, we estimated continuous primary production and discussed the relation between productivity and observed limnological parameters. Furthermore, we assessed the uncertainty of our modeling approach based on monthly 14C assimilation measurements using Monte Carlo simulations. Results confirm that monthly sampling of productivity is sufficient for identifying long-term trends in productivity and that conservation management has successfully improved water quality during the past three decades via reducing nutrients and primary production in the lake. However, even though nutrient concentrations have remained constant in recent years, annual primary production varies significantly from year to year. Despite the fact that nutrient concentrations have decreased by more than an order of magnitude, primary production has decreased only slightly. These results suggest that primary production correlates well to nutrients availability but meteorological conditions lead to interannual variability regardless of the trophic status of the lake. Accordingly, in oligotrophic freshwaters meteorological forcing may reduce productivity impacting on the entire food chain of the ecosystem.

  10. Virulent Coxiella burnetii pathotypes productively infect primary human alveolar macrophages.

    PubMed

    Graham, Joseph G; MacDonald, Laura J; Hussain, S Kauser; Sharma, Uma M; Kurten, Richard C; Voth, Daniel E

    2013-06-01

    The intracellular bacterial pathogen Coxiella burnetii is a category B select agent that causes human Q fever. In vivo, C. burnetii targets alveolar macrophages wherein the pathogen replicates in a lysosome-like parasitophorous vacuole (PV). In vitro, C. burnetii infects a variety of cultured cell lines that have collectively been used to model the pathogen's infectious cycle. However, differences in the cellular response to infection have been observed, and virulent C. burnetii isolate infection of host cells has not been well defined. Because alveolar macrophages are routinely implicated in disease, we established primary human alveolar macrophages (hAMs) as an in vitro model of C. burnetii-host cell interactions. C. burnetii pathotypes, including acute disease and endocarditis isolates, replicated in hAMs, albeit with unique PV properties. Each isolate replicated in large, typical PV and small, non-fused vacuoles, and lipid droplets were present in avirulent C. burnetii PV. Interestingly, a subset of small vacuoles harboured single organisms undergoing degradation. Prototypical PV formation and bacterial growth in hAMs required a functional type IV secretion system, indicating C. burnetii secretes effector proteins that control macrophage functions. Avirulent C. burnetii promoted sustained activation of Akt and Erk1/2 pro-survival kinases and short-termphosphorylation of stress-related p38. Avirulent organisms also triggered a robust, early pro-inflammatory response characterized by increased secretion of TNF-α and IL-6, while virulent isolates elicited substantially reduced secretion of these cytokines. A corresponding increase in pro- and mature IL-1β occurred in hAMs infected with avirulent C. burnetii, while little accumulation was observed following infection with virulent isolates. Finally, treatment of hAMs with IFN-γ controlled intracellular replication, supporting a role for this antibacterial insult in the host response to C

  11. Production of aluminum-26

    DOEpatents

    Steinkruger, Fred J.; Phillips, Dennis R.

    1991-01-01

    A method of producing Al-26 from potassium chloride by exposing it to a proton beam in order to break potassium and chlorine atoms into smaller pieces, which include Al-26. The Al-26 is isolated from the potassium chloride and other substances produced by the beam by means of extraction and ion exchange.

  12. Tight coupling of primary production and marine mammal reproduction in the Southern Ocean

    PubMed Central

    Paterson, J. Terrill; Rotella, Jay J.; Arrigo, Kevin R.; Garrott, Robert A.

    2015-01-01

    Polynyas are areas of open water surrounded by sea ice and are important sources of primary production in high-latitude marine ecosystems. The magnitude of annual primary production in polynyas is controlled by the amount of exposure to solar radiation and sensitivity to changes in sea-ice extent. The degree of coupling between primary production and production by upper trophic-level consumers in these environments is not well understood, which prevents reliable predictions about population trajectories for species at higher trophic levels under potential future climate scenarios. In this study, we find a strong, positive relationship between annual primary production in an Antarctic polynya and pup production by ice-dependent Weddell seals. The timing of the relationship suggests reproductive effort increases to take advantage of high primary production occurring in the months after the birth pulse. Though the proximate causal mechanism is unknown, our results indicate tight coupling between organisms at disparate trophic levels on a short timescale, deepen our understanding of marine ecosystem processes, and raise interesting questions about why such coupling exists and what implications it has for understanding high-latitude ecosystems. PMID:25854885

  13. Production of primary mirror segments for the Giant Magellan Telescope

    NASA Astrophysics Data System (ADS)

    Martin, H. M.; Allen, R. G.; Burge, J. H.; Davis, J. M.; Davison, W. B.; Johns, M.; Kim, D. W.; Kingsley, J. S.; Law, K.; Lutz, R. D.; Strittmatter, P. A.; Su, P.; Tuell, M. T.; West, S. C.; Zhou, P.

    2014-07-01

    Segment production for the Giant Magellan Telescope is well underway, with the off-axis Segment 1 completed, off-axis Segments 2 and 3 already cast, and mold construction in progress for the casting of Segment 4, the center segment. All equipment and techniques required for segment fabrication and testing have been demonstrated in the manufacture of Segment 1. The equipment includes a 28 m test tower that incorporates four independent measurements of the segment's figure and geometry. The interferometric test uses a large asymmetric null corrector with three elements including a 3.75 m spherical mirror and a computer-generated hologram. For independent verification of the large-scale segment shape, we use a scanning pentaprism test that exploits the natural geometry of the telescope to focus collimated light to a point. The Software Configurable Optical Test System, loosely based on the Hartmann test, measures slope errors to submicroradian accuracy at high resolution over the full aperture. An enhanced laser tracker system guides the figuring through grinding and initial polishing. All measurements agree within the expected uncertainties, including three independent measurements of radius of curvature that agree within 0.3 mm. Segment 1 was polished using a 1.2 m stressed lap for smoothing and large-scale figuring, and a set of smaller passive rigid-conformal laps on an orbital polisher for deterministic small-scale figuring. For the remaining segments, the Mirror Lab is building a smaller, orbital stressed lap to combine the smoothing capability with deterministic figuring.

  14. 40 CFR 52.2500 - Best available retrofit technology requirements for the Intalco Aluminum Corporation (Intalco...

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... requirements for the Intalco Aluminum Corporation (Intalco Works) primary aluminum plant-Better than BART... Best available retrofit technology requirements for the Intalco Aluminum Corporation (Intalco Works) primary aluminum plant—Better than BART Alternative. (a) Applicability. This section applies to...

  15. Role of eddy pumping in enhancing primary production in the ocean

    NASA Technical Reports Server (NTRS)

    Falkowski, Paul G.; Kolber, Zbigniew; Ziemann, David; Bienfang, Paul K.

    1991-01-01

    Eddy pumping is considered to explain the disparity between geochemical estimates and biological measurements of exported production. Episodic nutrient injections from the ocean into the photic zone can be generated by eddy pumping, which biological measurements cannot sample accurately. The enhancement of production is studied with respect to a cyclonic eddy in the subtropical Pacific. A pump-and-probe fluorimeter generates continuous vertical profiles of primary productivity from which the contributions of photochemical and nonphotochemical processes to fluorescence are derived. A significant correlation is observed between the fluorescence measurements and radiocarbon measurements. The results indicate that eddy pumping has an important effect on phytoplankton production and that this production is near the maximum relative specific growth rates. Based on the production enhancement observed in this case, eddy pumping increases total primary production by only 20 percent and does not account for all enhancement.

  16. ESTUARINE PHYTOPLANKTON PRIMARY PRODUCTION AND SIZE AS DETERMINED REMOTELY FROM AIRCRAFT AND COASTAL OBSERVATION

    EPA Science Inventory

    We used remotely sensed estimates of chlorophyll a and sea surface temperature, incorporated into the Chesapeake Bay Productivity Model (Harding et al., 2002), to estimate the spatial and temporal variation of phytoplankton net primary production and species size in the Narragans...

  17. Patterns of new versus recycled primary production in the terrestrial biosphere

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Nitrogen (N) and phosphorus (P) availability regulate plant productivity throughout the terrestrial biosphere, influencing the patterns and magnitude of net primary production (NPP) by land plants both now and into the future. These nutrients enter ecosystems via geologic and atmospheric pathways, a...

  18. Aluminum phosphide

    Integrated Risk Information System (IRIS)

    Aluminum phosphide ; CASRN 20859 - 73 - 8 Human health assessment information on a chemical substance is included in the IRIS database only after a comprehensive review of toxicity data , as outlined in the IRIS assessment development process . Sections I ( Health Hazard Assessments for Noncarcinoge

  19. Seasonal and tidal variations in primary and secondary productions in the Guadiana estuary, southeast of Portugal

    NASA Astrophysics Data System (ADS)

    Parli, B. V.; Galvao, H.

    2010-12-01

    Seasonal variations in surface water primary production, chlorophyll a, bacterial production, respiration rates and bacterial biomass were measured at four stations along decreasing salinity in the Guadiana estuary, southeast of Portugal between 1996 and 1997. Data collected showed distinct spatial and seasonal variations in microbial processes. Similarly tidal variations in primary and secondary productions were monitored at two stations- one near the mouth of the estuary (high salinity) and the other further upstream (low salinity). The impact of short-term (hourly to weekly) physico-chemical variabilities including turbidity, tides and nutrient pulses to seasonal variabilities including temperature, salinity and precipitation is discussed in this paper.

  20. Production of aluminum-silicon alloy and ferrosilicon and commercial purity aluminum by the direct reduction process. First interim technical report, Phase D, January 1-March 31, 1981

    SciTech Connect

    Bruno, M.J.

    1981-04-01

    Operation of the bench AF-reactor on burden with all reducing carbon exterior to the ore pellet resulted in low metal alloy product yields and prematurely terminated runs, indicating the need for intimate contact between alumina and carbon to produce oxycarbide liquid prior to reaction with solid silicon carbide. Carbon solubility tests made on 60Al-40Si alloys at 2200/sup 0/C in graphite crucibles indicated continued reaction to form SiC for one hour. Efficiency of reduction to SiC ranged from 68 to 100%. The A-C two-electrode submerged arc reactor pilot, SAR-II, was successfully operated on both alumina-clay-coke and alumina-silicon carbide-coke (from the VSR prereduction) burdens. Metal alloy was produced and tapped in each of four runs. The pilot crystallizer was operated to evalute the two-stage (stop and go) crystallization technique on obtaining high yields of Al in Al-Si eutectic, with a limit of 1.0% Fe and 0.1% Ti in the alloy product. 18 figures, 19 tables. (DLC)

  1. Primary productivity, bacterial productivity and nitrogen uptake in response to iron enrichment during the SEEDS II

    NASA Astrophysics Data System (ADS)

    Kudo, Isao; Noiri, Yoshifumi; Cochlan, William P.; Suzuki, Koji; Aramaki, Takafumi; Ono, Tsuneo; Nojiri, Yukihiro

    2009-12-01

    Primary productivity (PP), bacterial productivity (BP) and the uptake rates of nitrate and ammonium were measured using isotopic methods ( 13C, 3H, 15N) during a mesoscale iron (Fe)-enrichment experiment conducted in the western subarctic Pacific Ocean in 2004 (SEEDS II). PP increased following Fe enrichment, reached maximal rates 12 days after the enrichment, and then declined to the initial level on day 17. During the 23-day observation period, we observed the development and decline of the Fe-induced bloom. The surface mixed layer (SML) integrated PP increased by 3-fold, but was smaller than the 5-fold increase observed in the previous Fe-enrichment experiment conducted at almost the same location and season during 2001 (SEEDS). Nitrate uptake rates were enhanced by Fe enrichment but decreased after day 5, and became lower than ammonium uptake rates after day 17. The total nitrogenous nutrient uptake rate declined after the peak of the bloom, and accumulation of ammonium was obvious in the euphotic layer. Nitrate utilization accounted for all the requirements of N for the massive bloom development during SEEDS, whereas during SEEDS II, nitrate accounted for >90% of total N utilization on day 5, declining to 40% by the end of the observation period. The SML-integrated BP increased after day 2 and peaked twice on days 8 and 21. Ammonium accumulation and the delayed heterotrophic activity suggested active regeneration occurred after the peak of the bloom. The SML-integrated PP between days 0 and 23 was 19.0 g C m -2. The SML-integrated BP during the same period was 2.6 g C m -2, which was 14% of the SML-integrated PP. Carbon budget calculation for the whole experimental period indicated that 33% of the whole (particulate plus dissolved) PP (21.5 g C m -2) was exported below the SML and 18% was transferred to the meso-zooplankton (growth). The bacterial carbon consumption (43% of the whole PP) was supported by DOC or POC release from phytoplankton, zooplankton

  2. Automobile bodies: Can aluminum be an economical alternative to steel?

    NASA Astrophysics Data System (ADS)

    Roth, Richard; Clark, Joel; Kelkar, Ashish

    2001-08-01

    Although the use of aluminum in cars has been increasing for the past two decades, progress has been limited in developing aluminum auto bodies. In fact, most aluminum substitution has come in the form of castings and forgings in the transmission, wheels, etc. Car manufacturers have developed all-aluminum cars with two competing designs: conventional unibody and the spaceframe. However, aluminum is far from being a material of choice for auto bodies. The substitution of aluminum for steel is partly influenced by regulatory pressures to meet fuel efficiency standards by reducing vehicle weight, and to meet recycling standards. The key obstacles are the high cost of primary aluminum as compared to steel and added fabrication costs of aluminum panels. Both the aluminum and the automotive industries have attempted to make aluminum a cost-effective alternative to steel. This paper analyzes the cost of fabrication and assembly of four different aluminum car body designs, making comparisons with conventional steel designs at current aluminum prices and using current aluminum fabrication technology. It then attempts to determine if aluminum can be an alternative to steel at lower primary aluminum prices, and improved fabrication processes.

  3. Role of cyclonic eddy in enhancing primary and new production in the Bay of Bengal

    NASA Astrophysics Data System (ADS)

    Singh, Arvind; Gandhi, Naveen; Ramesh, R.; Prakash, S.

    2015-03-01

    Eddies can be important in sustaining primary production in the tropical oceans, but their role for nutrient cycling is poorly understood in the under-sampled northern Indian Ocean. To assess the role of cyclonic eddies in enhancing primary production, measurements of primary production were carried out at four stations in the northern Bay of Bengal during the early winter 2007, around a cyclonic eddy close to 17.8°N, 87.5°E. Shallowing of the thermocline and halocline by 10 m was observed within the eddy compared to the surroundings; mixed layer depth was also reduced within the eddy. The highest surface productivity (2.71 μM C d- 1) and chlorophyll a (0.18 μg L- 1) were found within the eddy, and the lowest, at its outer edge. Further, the eddy supplied nutrients to the surface layers, shallowing the subsurface chlorophyll maximum as well. Integrated production in the euphotic top layers was more than twice within the eddy compared to its outer edge, confirming the role of cyclonic eddies in enhancing the primary production in the otherwise less productive Bay of Bengal. Given new nitrogen input via vertical mixing, river discharge or aerosol deposition, the additional primary production due to this new nutrient input and its contribution to the total production (f-ratio, fraction of exportable organic matter) increased significantly from 0.4 to 0.7, and thus the Bay of Bengal can potentially transfer a high fraction of its total production to the deep, assisted by eddies. We suggest possible improvements in experiments for future studies, and the potential for assessing the role of eddies in biogeochemistry.

  4. Potential effects of global warming on the primary productivity of a subalpine lake

    SciTech Connect

    Bryon, E.R.; Goldman, C.R. Univ. of California, Davis )

    1990-12-01

    Atmospheric scientists have predicted that large-scale climatic changes will result from increasing levels of tropospheric CO{sub 2}. The authors have investigated the potential effects of climate change on the primary productivity of Castle Lake, a mountain lake in Northern California. Annual algal productivity was modeled empirically using 25 years of limnological data in order to establish predictive relationships between productivity and the climatic variables of accumulated snow depth and precipitation. The outputs of monthly temperature and precipitation from three general circulation models (GCMs) of doubled atmospheric CO{sub 2} were then used in the regression model to predict annual algal productivity. In all cases, the GCM scenarios predicted increased algal productivity for Castle Lake under conditions of doubled atmospheric CO{sub 2}. The primary cause of enhanced productivity was the increased length of the growing season resulting from earlier spring ice-out.

  5. Hot-spots of primary productivity: An Alternative interpretation to Conventional upwelling models

    NASA Astrophysics Data System (ADS)

    van Ruth, Paul D.; Ganf, George G.; Ward, Tim M.

    2010-12-01

    The eastern Great Australian Bight (EGAB) forms part of the Southern and Indian Oceans and is an area of high ecological and economic importance. Although it supports a commercial fishery, quantitative estimates of the primary productivity underlying this industry are open to debate. Estimates range from <100 mg C m -2 day -1 to > 500 mg C m -2 day -1. Part of this variation may be due to the unique upwelling circulation of shelf waters in summer/autumn (November-April), which shares some similarities with highly productive eastern boundary current upwelling systems, but differs due to the influence of a northern boundary current, the Flinders current, and a wide continental shelf. This study examines spatial variations in primary productivity in the EGAB during the upwelling seasons of 2005 and 2006. Daily integral productivity calculated using the vertically generalised production model (VGPM) showed a high degree of spatial variation. Productivity was low (<800 mg C m -2 day -1) in offshore central and western regions of the EGAB. High productivities (1600-3900 mg C m -2 day -1) were restricted to hotspots in the east that were influenced by the upwelled water mass. There was a strong correlation between the depth of the euphotic zone and the depth of the mixed layer that suggested that ˜50% of the euphotic zone lay below the mixed layer depth. As a result, high rates of primary productivity did not require upwelled water to reach the surface. A significant proportion of total productivity in the euphotic zone (57% in 2005 and 65% in 2006) occurred in the upwelled water mass below the surface mixed layer. This result has implications for daily integral productivities modelled with the VGPM, which uses surface measures of phytoplankton biomass to calculate productivity. Macro-nutrient concentrations could not be used to explain the difference in the low and high productivities (silica > 1 μmol L -1, nitrate/nitrite > 0.4 μmol L -1, phosphate > 0.1 μmol L -1

  6. Variation of phytoplankton biomass and primary production in Daya Bay during spring and summer.

    PubMed

    Song, Xingyu; Huang, Liangmin; Zhang, Jianlin; Huang, Xiaoping; Zhang, Junbin; Yin, Jianqiang; Tan, Yehui; Liu, Sheng

    2004-12-01

    Environmental factors, phytoplankton biomass (Chl a) and primary production of two water areas in Daya Bay (Dapeng'ao Bay and Aotou Bay) were investigated during the transition period from spring to summer. Chl a ranged from 3.20 to 13.62 and 13.43 to 26.49 mg m(-3) in Dapeng'ao Bay and Aotou Bay respectively, if data obtained during red tides are excluded. Primary production varied between 239.7 and 1001.4 mg Cm(-2) d(-1) in Dapeng'ao Bay. The regional distribution of Chl a and primary production were mostly consistent from spring to summer in both bays. Seasonal transition characters have been found in Daya Bay from spring to summer, including high values of DO, nitrate and silicate. Size structures of phytoplankton and its primary production do not change very much from spring to summer, with micro-phytoplankton dominating and contributing about 50% of the whole. In Daya Bay, phytoplankton is limited by nitrogen in spring, and by phosphate in summer. Artificial impacts are evident from high temperature effluent from nuclear power stations, aquaculture and sewage. During the investigation, a red tide occurred in Aotou Bay, with a maximum Chl a of 103.23 mgm(-3) at surface and primary production of 2721.9 mg Cm(-2) d(-1) in the red tide center. Raised water temperature and nutrient supply from land-sources help to stimulate annual red tides.

  7. Temperature dependence of CO2-enhanced primary production in the European Arctic Ocean

    NASA Astrophysics Data System (ADS)

    Holding, J. M.; Duarte, C. M.; Sanz-Martín, M.; Mesa, E.; Arrieta, J. M.; Chierici, M.; Hendriks, I. E.; García-Corral, L. S.; Regaudie-de-Gioux, A.; Delgado, A.; Reigstad, M.; Wassmann, P.; Agustí, S.

    2015-12-01

    The Arctic Ocean is warming at two to three times the global rate and is perceived to be a bellwether for ocean acidification. Increased CO2 concentrations are expected to have a fertilization effect on marine autotrophs, and higher temperatures should lead to increased rates of planktonic primary production. Yet, simultaneous assessment of warming and increased CO2 on primary production in the Arctic has not been conducted. Here we test the expectation that CO2-enhanced gross primary production (GPP) may be temperature dependent, using data from several oceanographic cruises and experiments from both spring and summer in the European sector of the Arctic Ocean. Results confirm that CO2 enhances GPP (by a factor of up to ten) over a range of 145-2,099 μatm however, the greatest effects are observed only at lower temperatures and are constrained by nutrient and light availability to the spring period. The temperature dependence of CO2-enhanced primary production has significant implications for metabolic balance in a warmer, CO2-enriched Arctic Ocean in the future. In particular, it indicates that a twofold increase in primary production during the spring is likely in the Arctic.

  8. Effects of ultraviolet radiation on the primary production of natural phytoplankton assemblages in Lake Michigan.

    PubMed

    Gala, W R; Giesy, J P

    1991-12-01

    Inhibition of primary production of offshore Lake Michigan phytoplankton assemblages by solar ultraviolet radiation (SUVR) was observed from April to October in 1986 during in situ incubations in special Plexiglas chambers. Inhibition of primary production by SUVR was observed to a depth of 6 m and at intensities which were approximately 1% of the UV-B intensity at the lake surface. Significant inhibition of primary production by SUVR was restricted to the top third of the euphotic zone. The order of relative sensitivities of offshore Lake Michigan phytoplankton assemblages during different seasons to inhibition by SUVR were spring ED50 = 17.6 kJ/m2 UV-B) greater than fall (ED50 = 30.5 kJ/m2 UV-B) greater than summer (ED50 = 131.6 kJ/m2 UV-B). A hazard assessment model predicted a significant reduction (13%) in areal (total water column) primary production for offshore Lake Michigan due to current SUVR intensities. Concern about possible increased reduction of primary production in the North American Great Lakes due to depletion of the stratospheric ozone layer appears to be unwarranted.

  9. Distributions of pigments and primary production in a Gulf Stream meander

    SciTech Connect

    Lohrenz, S.E.; Cullen, J.J.; Phinney, D.A.; Olson, D.B.; Yentsch, C.S.

    1993-08-15

    An investigation was made of physical effects of Gulf Stream meandering on the vertical and horizontal distributions of photosynthetic pigments and primary production. Cruises were conducted in the vicinity of a meander east of 73{degrees}W and north of 37{degrees}N from September 21 to October 5 (leg 1) and October 12-21, 1988 (leg 2), on the R/V Cape Hatteras. Relationships of photosynthesis (normalized to chlorophyll) to irradiance (P-I) did not show large horizontal variation, and water column composite P-I curves from leg 1 and leg 2 were similar. Therefore, a single P-I curve derived from pooled data was used to model distributions of primary production. Distributions of photosynthetic pigments were characterized on the basis of in vivo fluorescence profiles and empirical relationships with extracted pigment concentrations. Subsurface irradiance was described using a spectral irradiance model. Cross sections of the Gulf Stream revealed consistently higher pigment concentrations and primary production on the slope water side. Along-stream variations in pigment distributions and primary production were apparently related to density structure influenced by meander circulation. Such variations were less pronounced during leg 2, which came after a transition from a well-defined meander interacting with a warm-core ring (leg 1) to a more linear stream (leg 2). Higher water-column-integrated primary production during leg 2 was attributed to mixing-induced nutrient injection and redistribution of chlorophyll in the photic zone. 47 refs., 13 figs., 2 tabs.

  10. Investigating the influence of the Greenland Ice Sheet on marine primary productivity

    NASA Astrophysics Data System (ADS)

    Simmons, Sarah-Louise; Monteiro, Fanny; Wadham, Jemma; Death, Ros; Bamber, Jonathan

    2015-04-01

    Primary production in the ocean basins surrounding Greenland are largely thought to be limited by nitrogen, and in smaller regions by phosphorus, silica and iron. Recent work indicates that these biologically limiting elements are found in highly labile forms in glacial runoff from the Greenland Ice Sheet. Freshwater fluxes from the Greenland Ice Sheet have been increasing since 1992, and are projected to continue rising into the foreseeable future. Over the past decade limited evidence on small glacial catchments postulates that this meltwater impacts the biogeochemistry of the environment which they discharge into affecting productivity. However, the net impact of meltwater from the Greenland Ice Sheet on seasonal and annual marine productivity remains unclear; in large part due to diverging interests between modellers and field scientists. Joining together field and modelling approaches, this study is the first of its kind to be used to assess the effects of glacially derived meltwater from the Greenland Ice Sheet on ocean biogeochemistry and primary production of the North Atlantic Ocean. This study has identified spatial and temporal areas of nutrient limitation, and worked to quantify the influence of glacially derived nutrients on primary productivity in these regions, concluding in particular that meltwater could account for about 15% of primary production around the coast of Greenland in the summer.

  11. Responses of primary production, leaf litter decomposition and associated communities to stream eutrophication.

    PubMed

    Dunck, Bárbara; Lima-Fernandes, Eva; Cássio, Fernanda; Cunha, Ana; Rodrigues, Liliana; Pascoal, Cláudia

    2015-07-01

    We assessed the eutrophication effects on leaf litter decomposition and primary production, and on periphytic algae, fungi and invertebrates. According to the subsidy-stress model, we expected that when algae and decomposers were nutrient limited, their activity and diversity would increase at moderate levels of nutrient enrichment, but decrease at high levels of nutrients, because eutrophication would lead to the presence of other stressors and overwhelm the subsidy effect. Chestnut leaves (Castanea sativa Mill) were enclosed in mesh bags and immersed in five streams of the Ave River basin (northwest Portugal) to assess leaf decomposition and colonization by invertebrates and fungi. In parallel, polyethylene slides were attached to the mesh bags to allow colonization by algae and to assess primary production. Communities of periphytic algae and decomposers discriminated the streams according to the trophic state. Primary production decomposition and biodiversity were lower in streams at both ends of the trophic gradient.

  12. Responses of primary production, leaf litter decomposition and associated communities to stream eutrophication.

    PubMed

    Dunck, Bárbara; Lima-Fernandes, Eva; Cássio, Fernanda; Cunha, Ana; Rodrigues, Liliana; Pascoal, Cláudia

    2015-07-01

    We assessed the eutrophication effects on leaf litter decomposition and primary production, and on periphytic algae, fungi and invertebrates. According to the subsidy-stress model, we expected that when algae and decomposers were nutrient limited, their activity and diversity would increase at moderate levels of nutrient enrichment, but decrease at high levels of nutrients, because eutrophication would lead to the presence of other stressors and overwhelm the subsidy effect. Chestnut leaves (Castanea sativa Mill) were enclosed in mesh bags and immersed in five streams of the Ave River basin (northwest Portugal) to assess leaf decomposition and colonization by invertebrates and fungi. In parallel, polyethylene slides were attached to the mesh bags to allow colonization by algae and to assess primary production. Communities of periphytic algae and decomposers discriminated the streams according to the trophic state. Primary production decomposition and biodiversity were lower in streams at both ends of the trophic gradient. PMID:25797823

  13. Aluminum-air battery crystallizer

    SciTech Connect

    Maimoni, A.

    1987-01-01

    A prototype crystallizer system for the aluminum-air battery operated reliably through simulated startup and shutdown cycles and met its design objectives. The crystallizer system allows for crystallization and removal of the aluminum hydroxide reaction product; it is required to allow steady-state and long-term operation of the aluminum-air battery. The system has to minimize volume and maintain low turbulence and shear to minimize secondary nucleation and energy consumption while enhancing agglomeration. A lamella crystallizer satisfies system constraints.

  14. Evaluation of bio-optical algorithms to remotely sense marine primary production from space

    NASA Technical Reports Server (NTRS)

    Berthelot, Beatrice; Deschamps, Pierre-Yves

    1994-01-01

    In situ bio-optical measurements from several oceanographic campaigns were analyzed to derive a direct relationship between water column primary production P (sub t) ocean color as expressed by the ratio of reflectances R (sub 1) at 440 nm and R (sub 3) at 550 nm and photosynthetically available radiation (PAR). The study is restricted to the Morel case I waters for which the following algorithm is proposed: log (P(sub f)) = -4.286 - 1.390 log (R(sub 1)/R(sub3)) + 0.621 log (PAR), with P(sub t) in g C m(exp -2)/d and PAR in J m(exp -2)/d. Using this algorithm the rms accuracy of primary production estimate is 0.17 on a logarithmic scale, i.e., a factor of 1.5. Using spectral reflectance measurements in the entire visible spectral range, the central wavelength, spectral bandwidth, and radiometric noise level requirements are investigated for the channels to be used by an ocean color space mission dedicated to estimating global marine primary production and the associated carbon fluxes. Nearly all the useful information is provided by two channels centered at 440 nm and 550 nm, but the accuracy of primary production estimate appears weakly sensitive to spectral bandwidth, which, consequently, may be enlarged by several tens of nanometers. The sensitivity to radiometric noise, on the contrary, is strong, and a noise equivalent reflectance of 0.005 degraded the accuracy on the primary production estimate by a factor 2 (0.14-0.25 on a logarithmic scale). The results should be applicable to evaluating the primary production of oligotrophic and mesotrophic waters, which constitute most of the open ocean.

  15. Estimates of the cost and energy consumption of aluminum-air electric vehicles

    SciTech Connect

    Cooper, J.F.

    1980-11-01

    Economic costs and primary energy consumption are estimated for general purpose electric vehicles using aluminum-air propulsion batteries within the time frame of the 1990's (earliest possible date of introduction). Critical assumptions are given. The results show that, for a 40 kW, 70 kWh battery used in a vehicle traveling 16,000 km/y, the total capital investment in electricity and aluminum production plants and fuels distribution system was $2250 or $32/kWh. Of this, the aluminum plants contributed 60%, and the fuels distribution system, 3% (less than $1/kWh). The introduction of 1,000,000 vehicles per year in 1995 would increase domestic aluminum demand by below 5% per year, and electricity demand by less than 0.2% per year.

  16. Distribution and controlling mechanisms of primary production on the Louisiana Texas continental shelf

    NASA Astrophysics Data System (ADS)

    Chen, X.; Lohrenz, S. E.; Wiesenburg, D. A.

    2000-06-01

    The northwest (NW) Gulf of Mexico is marked by strong seasonal patterns in regional and mesoscale circulation and variable effects of riverine/estuarine discharge, which influence distributions of nutrients, phytoplankton biomass and primary production. During a series of five cruises in the NW Gulf of Mexico in 1993 and 1994, an extensive data set was collected including nutrients, phytoplankton biomass (chlorophyll a), and photosynthesis-irradiance ( P- E) parameters. Primary production was estimated using P- E parameters in conjunction with profiles of biomass and irradiance. Relatively high biomass and primary production were observed in inner shelf waters during spring conditions of high river discharge. This was attributed to the retention of biomass and nutrients on the shelf by the combination of high river outflow and a westward flow along the inner shelf with consequent onshore Ekman component. During summer, when surface currents shifted towards the north and east, values of nutrients, biomass and primary production were relatively high east of Galveston Bay and decreased outward from the coast. This pattern was apparently a consequence of nutrient inputs from riverine, upwelling and benthic sources. Nutrients, biomass and productivity in the western portion of the study area in summer were generally lower as a result of the upcoast flow of oligotrophic offshore water. Inter-annual variability was observed between November 1993 and 1994 with higher biomass and productivity occurring in November 1993. This was partially attributed to higher river discharge prior to November 1993, retention of biomass and nutrients by the downcoast flow along the inner shelf, and possibly, injection of nutrients onto the shelf at the shelf break. Our findings demonstrate that the interaction of circulation and availability of light and nutrients are largely responsible for variations in primary production. Nitrogen appeared to be the primary limiting nutrient, however, a

  17. Primary productivity and nitrogen assimilation with identifying the contribution of urea in Funka Bay, Japan

    NASA Astrophysics Data System (ADS)

    Kudo, Isao; Hisatoku, Takatsugu; Yoshimura, Takeshi; Maita, Yoshiaki

    2015-06-01

    Primary production is supported by utilization of several forms of nitrogen (N), such as nitrate, ammonium, and urea. Nevertheless, only few studies have measured the concentration and uptake of urea despite its importance as a nitrogenous nutrient for phytoplankton. We measured primary productivity monthly at four depths within the euphotic zone using a clean technique and the 13C method by a 24 h in situ mooring incubation over a year in Funka Bay, a subarctic coastal area in Japan, to make better updated estimates (re-evaluation) of annual primary production. Nitrogenous (N) nutrient assimilation rates (nitrate, ammonium and urea) were also measured to elucidate the relative contributions of these nutrients to autotrophic production and to distinguish between new and regenerated production. The estimated annual primary production was 164 g C m-2, which was 40-60% higher than the previously reported values in the bay. Use of a clean technique and more frequent measurement during the spring bloom may have contributed to the higher rates. The production during the spring bloom was 56.5 g C m-2, accounting for 35% of the annual production. The maximum daily productivity occurred in the bloom at 1.4 g C m-2 d-1, which is one of the highest values among the world embayments. The annual primary production in the bay was classified as mesotrophic state based on the classification by Cloern et al. (2014). The assimilation rate of nitrate was maximal at 54 nmol N L-1 h-1 during the bloom. During the post-bloom periods with nitrate depleted conditions, assimilation rates of ammonium and urea increased and accounted for up to 85% of the total N assimilation. The assimilation rate of urea was almost comparable to that of ammonium throughout the year. Taking urea into account, the f-ratio ranged from 0.15 under the nitrate-depleted conditions to 0.8 under the spring bloom conditions. These ratios were overestimated by 50% and 10%, respectively, if urea uptake was eliminated

  18. Aluminum-air battery for automotive propulsion

    SciTech Connect

    Cooper, J.F.; Behrin, E.

    1980-12-01

    Research on the development of aluminum-air batteries which will be used in energy efficient, economical electric vehicles is reviewed with information on the research strategy, performance characteristics of aluminum-air cells, vehicle design, and the net energy required and energy costs for producing and operating Al-air batteries. The aluminum-air battery is being developed to provide a propulsion source for a general-purpose electric vehicle that has the acceleration, range, and rapid-refueling characteristics of current automobiles. The objective is petroleum conservation in a time frame in which synthetic liquids will enter large scale production. Two parallel development paths are being pursued. These involve hardware developments using model electrodes, and research directed toward cost-effective electrodes. The project is currently directed toward developing rapidly-refuelable single cells. Successful development of battery hardware and electrodes would make possible a general-purpose vehicle with costs and energy consumption similar to advanced ICE vehicles using fuels synthesized from coal, but with the advantages of a broad primary energy base and an emissionless vehicle. (LCL)

  19. The effects of temporal variability of mixed layer depth on primary productivity around Bermuda

    NASA Technical Reports Server (NTRS)

    Bissett, W. Paul; Meyers, Mark B.; Walsh, John J.; Mueller-Karger, Frank E.

    1994-01-01

    Temporal variations in primary production and surface chlorophyll concentrations, as measured by ship and satellite around Bermuda, were simulated with a numerical model. In the upper 450 m of the water column, population dynamics of a size-fractionated phytoplankton community were forced by daily changes of wind, light, grazing stress, and nutrient availability. The temporal variations of production and chlorophyll were driven by changes in nutrient introduction to the euphotic zone due to both high- and low-frequency changes of the mixed layer depth within 32 deg-34 deg N, 62 deg-64 deg W between 1979 and 1984. Results from the model derived from high-frequency (case 1) changes in the mixed layer depth showed variations in primary production and peak chlorophyll concentrations when compared with results from the model derived from low-frequency (case 2) mixed layer depth changes. Incorporation of size-fractionated plankton state variables in the model led to greater seasonal resolution of measured primary production and vertical chlorophyll profiles. The findings of this study highlight the possible inadequacy of estimating primary production in the sea from data of low-frequency temporal resolution and oversimplified biological simulations.

  20. Impact of Chromophoric Dissolved Organic Matter on UV Inhibition of Primary Productivity in the Sea

    NASA Technical Reports Server (NTRS)

    Arrigo, Kevin R.; Brown, Christopher W.

    1996-01-01

    A model was developed to assess the impact of chromophoric dissolved organic matter (CDOM) on phytoplankton production within the euphotic zone. The rate of depth-integrated daily gross primary productivity within the euphotic zone was evaluated as a function of date, latitude, CDONI absorption characteristics, chlorophyll a (chl a) concentration, vertical stratification, and phytoplankton sensitivity to UV radiation (UVR). Results demonstrated that primary production was enhanced in the upper 30 m of the water column by the presence of CDOM, where predicted increases in production due to the removal of damaging UVR more than offset its reduction resulting from the absorption of photosynthetically usable radiation. At greater depths, where little UVR remained, primary production was always reduced due to removal by CDOM of photosynthetically usable radiation. When CDOM was distributed homogeneously within the euphotic zone, the integral over z [(GPP)(sub ez)], was reduced under most bio-optical (i.e. solar zenith angle, and CDOM absorption, and ozone concentration) and photophysiological production at depth was greater than the enhancement of production at the surface.

  1. Primary productivity by phytoplankton in the tidal, fresh Potomac River, Maryland, May 1980 to August 1981

    USGS Publications Warehouse

    Cohen, R.R.; Pollock, S.O.

    1983-01-01

    Primary productivity by phytoplankton was measured on samples collected from the Potomac Tidal River, Maryland. The studies were performed monthly from May 1980 to September 1981. Additional studies were done once a week in August 1980, twice a week from August 4 to 8, 1980 and twice in September 1980. Depth-integrated samples were collected at five stations and incubated in boxes that were exposed to natural sunlight. The boxes were covered with neutral density filters transmitting 100 , 65, 32, 16, and 6 percent surface light. River water was pumped continuously over the samples. The extinction of light in the water column by phytoplankton was measured when samples were collected. Experiments were performed to select a method for routine productivity analysis. No difference was found between productivity: (1) determined in situ and in boxes; (2) measured in 300 ml and (4) calculated from short term (4 hours) and long term (10-24 hours) incubations. There were higher productivity differences in samples that were rotated among different light intensities every 15 minutes (simulating mixing) than those remaining stationary. Respiration was significantly less in samples pumped through a hose from those collected using a depth-integrating sampler. Depth-integrated primary productivity was determined from the productivity data using an equation modified from one reported in the literature. Depth-integrated gross primary productivity was highest in August 1980 and 1981 and lowest in January 1980. (USGS)

  2. Issues in the melting and reclamation of aluminum scrap

    NASA Astrophysics Data System (ADS)

    Peterson, Ray D.

    1995-02-01

    The processing of aluminum scrap has been practiced for as long as aluminum has been produced due to the inherent value of the metal and the amount of energy required to produce primary aluminum from bauxite ore. Scrap can be remelted at a fraction of the expense. With the large-scale introduction of aluminum beverage containers in the 1970s, increases in energy costs, and the need to reduce solid waste, aluminum recycling has grown at an increasing rate. This article provides a overview of the technologies and issues that surround the melting and reclamation of aluminum scrap.

  3. Effects of fluoride emissions from a modern primary aluminum smelter on a local population of white-tailed deer (Odocoileus virginianus)

    SciTech Connect

    Suttie, J.S.; Dickie, R.; Clay, A.B.; Nielsen, P.; Mahan, W.E.; Baumann, D.P.; Hamilton, R.J.

    1987-01-01

    The influence of fluoride emissions from a modern aluminum smelter on concentrations of skeletal fluoride and dental fluorosis in a resident population of white-tailed deer was studied. The smelter was located on Mount Holly Plantation in South Carolina, and concentrations of skeletal fluoride in the deer collected at Mount Holly increased approximately five-fold 3 yr after the operation began. Increases in skeletal fluoride of less than two-fold were observed in deer obtained from Medway Plantation which has its nearest boundary 1.6 km from the smelter site. No dental fluorosis was observed in deer collected at Medway Plantation, but mild dental fluorosis was observed in a significant number of deer collected at Mount Holly Plantation. The dental fluorosis that was observed was not associated with incisor wear or with fluoride-induced molar wear. Osteofluorosis of mandibles or metacarpals was not observed in any of the deer obtained from either plantation. The data obtained from this study indicated that the presence of a modern aluminum smelter caused a detectable increase in concentration of skeletal fluoride in the resident population of white-tailed deer, but that no adverse health effects were seen.

  4. Benthic primary production in an upwelling-influenced coral reef, Colombian Caribbean

    PubMed Central

    Bayraktarov, Elisa; Hauffe, Torsten; Pizarro, Valeria; Wilke, Thomas; Wild, Christian

    2014-01-01

    In Tayrona National Natural Park (Colombian Caribbean), abiotic factors such as light intensity, water temperature, and nutrient availability are subjected to high temporal variability due to seasonal coastal upwelling. These factors are the major drivers controlling coral reef primary production as one of the key ecosystem services. This offers the opportunity to assess the effects of abiotic factors on reef productivity. We therefore quantified primary net (Pn) and gross production (Pg) of the dominant local primary producers (scleractinian corals, macroalgae, algal turfs, crustose coralline algae, and microphytobenthos) at a water current/wave-exposed and-sheltered site in an exemplary bay of Tayrona National Natural Park. A series of short-term incubations was conducted to quantify O2 fluxes of the different primary producers during non-upwelling and the upwelling event 2011/2012, and generalized linear models were used to analyze group-specific O2 production, their contribution to benthic O2 fluxes, and total daily benthic O2 production. At the organism level, scleractinian corals showed highest Pn and Pg rates during non-upwelling (16 and 19 mmol O2 m−2 specimen area h−1), and corals and algal turfs dominated the primary production during upwelling (12 and 19 mmol O2 m−2 specimen area h−1, respectively). At the ecosystem level, corals contributed most to total Pn and Pg during non-upwelling, while during upwelling, corals contributed most to Pn and Pg only at the exposed site and macroalgae at the sheltered site, respectively. Despite the significant spatial and temporal differences in individual productivity of the investigated groups and their different contribution to reef productivity, differences for daily ecosystem productivity were only present for Pg at exposed with higher O2 fluxes during non-upwelling compared to upwelling. Our findings therefore indicate that total benthic primary productivity of local autotrophic reef communities is

  5. Twenty-million-year relationship between mammalian diversity and primary productivity.

    PubMed

    Fritz, Susanne A; Eronen, Jussi T; Schnitzler, Jan; Hof, Christian; Janis, Christine M; Mulch, Andreas; Böhning-Gaese, Katrin; Graham, Catherine H

    2016-09-27

    At global and regional scales, primary productivity strongly correlates with richness patterns of extant animals across space, suggesting that resource availability and climatic conditions drive patterns of diversity. However, the existence and consistency of such diversity-productivity relationships through geological history is unclear. Here we provide a comprehensive quantitative test of the diversity-productivity relationship for terrestrial large mammals through time across broad temporal and spatial scales. We combine >14,000 occurrences for 690 fossil genera through the Neogene (23-1.8 Mya) with regional estimates of primary productivity from fossil plant communities in North America and Europe. We show a significant positive diversity-productivity relationship through the 20-million-year record, providing evidence on unprecedented spatial and temporal scales that this relationship is a general pattern in the ecology and paleo-ecology of our planet. Further, we discover that genus richness today does not match the fossil relationship, suggesting that a combination of human impacts and Pleistocene climate variability has modified the 20-million-year ecological relationship by strongly reducing primary productivity and driving many mammalian species into decline or to extinction. PMID:27621451

  6. Bacterial and primary production in the pelagic zone of the Kara Sea

    NASA Astrophysics Data System (ADS)

    Sazhin, A. F.; Romanova, N. D.; Mosharov, S. A.

    2010-10-01

    Data on the bacterial and primary production, which were obtained simultaneously for the same water samples, are presented for three regions of the Kara Sea. The samples were collected for the transect westwards of the Yamal Peninsula, along the St. Anna Trough, and the transect in Ob Bay. Direct counts of the DAPI-stained bacterial cells were performed. The bacterial production and grazing rates were determined using a direct method when metabolic inhibitors vancomycin and penicillin were added. The primary production rates were estimated using the 14C method. The average primary production was 112.6, 58.5, and 28.7 mg C m-2 day-1, and the bacterial production was 12.8, 48.9, and 81.6 mg C m-2 day-1 along the Yamal Peninsula, the St. Anna Trough, and Ob Bay, respectively. The average bacterial carbon demand was 34.6, 134.5, and 220.4 mg C m-2 day-1 for these regions, respectively. The data obtained lead us to conclude that the phytoplankton-synthesized organic matter is generally insufficient to satisfy the bacterial carbon demand and may be completely assimilated via the heterotrophic processes in the marine ecosystems. Therefore, the bacterial activity and, consequently, the amount of the synthesized biomass (i.e., the production) both depend directly on the phytoplankton’s condition and activity. We consider these relationships to be characteristics of the Kara Sea’s biota.

  7. Primary Production Reconstructions in the Late Quaternary Tropical Indo Pacific Oceans

    NASA Astrophysics Data System (ADS)

    Beaufort, L.; Barbarin, N.; Mariotti, V.; Bopp, L.; Braconnot, P.; Gally, Y.; Buchet, N.; Ermini, M.

    2012-12-01

    Primary Production (PP) in the Tropical ocean depends essentially on arrival of nutrients in the photic zone. The depth of the nutricline is, in most of the case, related to the structure of the upper ocean (thermocline, mixed-layer depth...) and in large part to the wind dynamics. Monitoring past primary production changes can help to reconstruct past dynamics of some important atmospheric features such as Monsoon or El Nino Like. In order to estimates past primary production we used composition of coccolithophores assemblages, which are a diagnostic tool commonly used. Our data set is composed of 12 published records and 7 new records obtained by the most recent version of an automatic system which routinely counts coccolithophore species. This data set is used to trace PP in space and time. The data set is compared with the results of numerical simulations of PP produced by IPSLCM5 in the tropical IndoPacific for the mid Holocene and Last Glacial Maximum. Strong resemblances exist between the two methods. Long time series of the proxy data indicate that precession is an important parameter in the dynamics of primary production and monsoon. Semi-precession and Glacial-Interglacial are also important aspect of the PP dynamics.

  8. Modeling the Response of Nutrient Concentrations and Primary Productivity in Lake Michigan to Nutrient Loading Scenarios

    EPA Science Inventory

    A water quality model, LM3 Eutro, will be used to estimate the response of nutrient concentrations and primary productivity in Lake Michigan to nutrient loading scenarios. This work is part of a larger effort, the Future Midwestern landscapes study, that will estimate the produc...

  9. The Potential of Carbonyl Sulfide as a Tracer for Gross Primary Productivity at Flux Tower Sites

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Regional/continental scale studies of atmospheric carbonyl sulfide (OCS) seasonal dynamics and leaf level studies of plant OCS uptake have shown a close relationship to CO2 dynamics and uptake, suggesting potential for OCS as a tracer for gross primary productivity (GPP). Canopy CO2 and OCS differen...

  10. 40 CFR 63.11164 - What General Provisions apply to primary zinc production facilities?

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... CFR part 63, subpart A, according to Table 1 to this subpart and paragraphs (a)(1) through (3) of this... the General Provisions (40 CFR part 63, subpart A) as provided in Table 1 to this subpart and... primary zinc production facilities? 63.11164 Section 63.11164 Protection of Environment...

  11. 40 CFR 63.11164 - What General Provisions apply to primary zinc production facilities?

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... CFR part 63, subpart A, according to Table 1 to this subpart and paragraphs (a)(1) through (3) of this... the General Provisions (40 CFR part 63, subpart A) as provided in Table 1 to this subpart and... primary zinc production facilities? 63.11164 Section 63.11164 Protection of Environment...

  12. 40 CFR 63.11164 - What General Provisions apply to primary zinc production facilities?

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... CFR part 63, subpart A, according to Table 1 to this subpart and paragraphs (a)(1) through (3) of this... the General Provisions (40 CFR part 63, subpart A) as provided in Table 1 to this subpart and... primary zinc production facilities? 63.11164 Section 63.11164 Protection of Environment...

  13. 40 CFR 63.11164 - What General Provisions apply to primary zinc production facilities?

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... CFR part 63, subpart A, according to Table 1 to this subpart and paragraphs (a)(1) through (3) of this... the General Provisions (40 CFR part 63, subpart A) as provided in Table 1 to this subpart and... primary zinc production facilities? 63.11164 Section 63.11164 Protection of Environment...

  14. 40 CFR 63.11166 - What General Provisions apply to primary beryllium production facilities?

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... comply with all of the requirements of the General Provisions in 40 CFR part 61, subpart A. (b) You must comply with the requirements of the General Provisions in 40 CFR part 63, subpart A, that are specified... primary beryllium production facilities? 63.11166 Section 63.11166 Protection of Environment...

  15. 40 CFR 63.11166 - What General Provisions apply to primary beryllium production facilities?

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... comply with all of the requirements of the General Provisions in 40 CFR part 61, subpart A. (b) You must comply with the requirements of the General Provisions in 40 CFR part 63, subpart A, that are specified... primary beryllium production facilities? 63.11166 Section 63.11166 Protection of Environment...

  16. 40 CFR 63.11166 - What General Provisions apply to primary beryllium production facilities?

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... comply with all of the requirements of the General Provisions in 40 CFR part 61, subpart A. (b) You must comply with the requirements of the General Provisions in 40 CFR part 63, subpart A, that are specified... primary beryllium production facilities? 63.11166 Section 63.11166 Protection of Environment...

  17. 40 CFR 63.11166 - What General Provisions apply to primary beryllium production facilities?

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... comply with all of the requirements of the General Provisions in 40 CFR part 61, subpart A. (b) You must comply with the requirements of the General Provisions in 40 CFR part 63, subpart A, that are specified... primary beryllium production facilities? 63.11166 Section 63.11166 Protection of Environment...

  18. 40 CFR 63.11166 - What General Provisions apply to primary beryllium production facilities?

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... comply with all of the requirements of the General Provisions in 40 CFR part 61, subpart A. (b) You must comply with the requirements of the General Provisions in 40 CFR part 63, subpart A, that are specified... primary beryllium production facilities? 63.11166 Section 63.11166 Protection of Environment...

  19. 40 CFR 63.11164 - What General Provisions apply to primary zinc production facilities?

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... CFR part 63, subpart A, according to Table 1 to this subpart and paragraphs (a)(1) through (3) of this... the General Provisions (40 CFR part 63, subpart A) as provided in Table 1 to this subpart and... primary zinc production facilities? 63.11164 Section 63.11164 Protection of Environment...

  20. Palynological evidence for late Quaternary climate and marine primary productivity changes along the California margin

    NASA Astrophysics Data System (ADS)

    Pospelova, Vera; Price, Andrea M.; Pedersen, Thomas F.

    2015-07-01

    A high-resolution sedimentary record of dinoflagellate cysts from Ocean Drilling Program Hole 1017E (off Point Conception, California margin) reflects how marine primary productivity has changed in response to major shifts in climate and ocean circulation along the California margin over the past 42 kyr. Throughout the studied sequence, dinoflagellate cyst assemblages are dominated by upwelling-related taxa, signifying the continued presence of coastal upwelling on the margin during the late Quaternary. The cyst record suggests that marine primary productivity was enhanced during the Holocene and Bølling, and to a lesser extent, during the late glacial and most Dansgaard-Oeschger events, while an apparent reduction in primary productivity can be seen during the Younger Dryas. The best analogue technique, based on a modern dinoflagellate cyst assemblage database from the northeast Pacific, was used for quantitative reconstruction of past sea surface conditions. It points to dynamic changes in annual marine primary productivity (~235-331 g C m-2 yr-1) and sea surface temperature (~10.1-12.6°C in winter; ~13.1-14.3°C in summer), while sea surface salinity appears to be confined to a narrower range (~32.9-33.4 in summer). Our results also indicate noticeable climate variability during the Holocene in this region.

  1. Resource and Production, A Primary Unit in Cultural Geography. Pupil Text and Workbook and Teacher Manual.

    ERIC Educational Resources Information Center

    Imperatore, William

    This is an instructional unit in cultural geography for the primary grades. The major objective of the unit, which is comprised of a Pupil Text/Workbook and Teacher Manual, is to develop the geographic concepts labeled resource and production. Teaching strategies used include the Pestalozzian method of asking leading questions to draw the students…

  2. Deconstructing Immigrant Girls' Identities through the Production of Visual Narratives in a Catalan Urban Primary School

    ERIC Educational Resources Information Center

    Rifa-Valls, Montserrat

    2009-01-01

    In this article, the research findings of a deconstructive visual ethnography focused on the production of immigrant girls' identities will be analysed. This collaborative research project involved experimentation with a dialogic curriculum aimed at creating diverse identity narratives with immigrant girls at an urban primary school in Barcelona.…

  3. Legacies of precipitation fluctuations on primary production: Theory and data synthesis

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Variability of aboveground net primary production (ANPP) of arid to sub-humid ecosystems displays a closer association with precipitation when considered across space, based on multiyear averages for different locations, than through time, based on year to year change at single locations. Here, we p...

  4. Legacies of precipitation fluctuations on primary production: theory and data synthesis

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Variability of above-ground net primary production (ANPP) of arid to sub-humid ecosystems displays a closer association with precipitation when considered across space (based on multiyear averages for different locations) than through time (based on year-to-year change at single locations). Here, we...

  5. A model study of seasonal mixed-layer primary production in the Arabian Sea

    NASA Astrophysics Data System (ADS)

    Brock, John; Sathyendranath, Shubha; Platt, Trevor

    1994-06-01

    We combined a surface irradiance model with a non-spectral photosynthesisirradiance model to estimate the daily, average rate of mixed-layer primary production in the Arabian Sea for the 15th day of months at the end of the northeast monsoon, the southwest monsoon, and the fall and spring inter-monsoons. Our model experiment uses climatologies of cloud cover, mixed-layer thickness, and satellite ocean-color observations of phytoplankton biomass. Modelled surface radiation is at an annual maximum in May beneath nearly cloud-free skies just prior to the summer solstice. The model estimate of surface radiation diminishes through the southwest monsoon over most of the northern Arabian Sea to an annual minimum in August due to intense cloudiness. In agreement with previous ship-based measurements, the photosynthesis-irradiance model predicts that the mixed-layer primary production in the Arabian Sea is extremely seasonal, and peaks annually during the southwest monsoon to the north-west of the atmospheric Findlater Jet and along the coast of Somalia. Northern Arabian Sea maxima predicted for both the summer and winter monsoons are separated by periods of low mixed-layer primary production, the fall and spring inter-monsoons. The annual cycles of modelled mixed-layer primary production differ by region in the Arabian Sea due to varying monsoon influence and circulation dynamics.

  6. 24 CFR 3282.362 - Production Inspection Primary Inspection Agencies (IPIAs).

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 24 Housing and Urban Development 5 2010-04-01 2010-04-01 false Production Inspection Primary Inspection Agencies (IPIAs). 3282.362 Section 3282.362 Housing and Urban Development Regulations Relating to Housing and Urban Development (Continued) OFFICE OF ASSISTANT SECRETARY FOR HOUSING-FEDERAL...

  7. Global 4 km resolution monthly gridded Gross Primary Productivity (GPP) data set derived from FLUXNET2015

    DOE Data Explorer

    Kumar, Jitendra; Hoffman, Forrest M.; Hargrove, William W.; Collier, Nathan

    2016-08-01

    This data set contain global gridded surfaces of Gross Primary Productivity (GPP) at 2 arc minute (approximately 4 km) spatial resolution monthly for the period of 2000-2014 derived from FLUXNET2015 (released July 12, 2016) observations using a representativeness based upscaling approach.

  8. Effec of high-temperature decomposition of the solid solution on the low-cycle fatigue resistance of semifinished products made of aluminum alloy 1163

    SciTech Connect

    Teleshov, V.V.; Kuzginov, V.I.; Golovleva, A.P.

    1995-11-01

    The surface of anodized parts made of 1163T aluminum alloy that are produced by mechanical treatment of large pressed or rolled semifinished products exhibits dark regions. These regions have a higher electrical conductivity {gamma} than the rest of the anodized surface, colored light-yellow. Some authors explain the appearance of the dark stains by high-temperature decomposition of the solid solution, which is initiated by secondary heating of these surface regions due to the heat of surrounding volumes in random interruptions of the cooling process. The aim of the present work is to refine the dependence of {gamma}on the endurance in tests for low-cycle fatigue of specimens from semifinished products made of 1163 alloy in order to establish the intensity of the decrease of the endurance and the admissible increase of {gamma} in the region of dark stains.

  9. Aluminum-induced cell death of barley-root border cells is correlated with peroxidase- and oxalate oxidase-mediated hydrogen peroxide production.

    PubMed

    Tamás, L; Budíková, S; Huttová, J; Mistrík, I; Simonovicová, M; Siroká, B

    2005-06-01

    The function of root border cells (RBC) during aluminum (Al) stress and the involvement of oxalate oxidase, peroxidase and H(2)O(2) generation in Al toxicity were studied in barley roots. Our results suggest that RBC effectively protect the barley root tip from Al relative to the situation in roots cultivated in hydroponics where RBC are not sustained in the area surrounding the root tip. The removal of RBC from Al-treated roots increased root growth inhibition, Al and Evans blue uptake, inhibition of RBC production, the level of dead RBC, peroxidase and oxalate oxidase activity and the production of H(2)O(2). Our results suggest that even though RBC actively produce active oxygen species during Al stress, their role in the protection of root tips against Al toxicity is to chelate Al in their dead cell body.

  10. Effects of aluminum on phosphate metabolism in rats: a possible interaction with vitamin D3 renal production.

    PubMed

    Mahieu, Stella T; Navoni, Julio; Millen, Néstor; del Carmen Contini, María; Gonzalez, Marcela; Elías, María Mónica

    2004-11-01

    The effect of chronic aluminum (Al) administration on the phosphorous (Pi) metabolism of different target tissues was studied. Male Wistar rats received aluminum lactate for 3 months (5.75 mg/kg bodyweight of Al, i.p., three times per week). The animals were studied at the end of the 1st, 2nd and 3rd month of treatment. They were housed individually in metabolic cages for 4 days to study Pi and calcium (Ca) balance. Daily food and water intakes were recorded for all animals and urine and feces were collected for Pi and calcium assays. After 3 months the Pi intestinal absorption and the Pi deposition in bone were studied using 32Pi. Another group of rats was treated daily for 7 days with calcitriol (0.08 microg/kg body weight in sesame oil, i.p.) and the Pi balance was studied for the last 4 days. The results indicated that chronic administration of Al affected simultaneously the Pi and calcium balance, with a significant diminution of calcium and increased Pi accretion in bones, together with a diminution in the intestinal absorption of Pi. The treatment of the rats with calcitriol promoted a normalized Pi balance in Al treated rats. These findings suggest that Al could modify the Pi metabolism acting directly on intestine, kidney and bone, or indirectly through possible changes in the levels of vitamin D3. PMID:15221202

  11. Effects of aluminum on phosphate metabolism in rats: a possible interaction with vitamin D3 renal production.

    PubMed

    Mahieu, Stella T; Navoni, Julio; Millen, Néstor; del Carmen Contini, María; Gonzalez, Marcela; Elías, María Mónica

    2004-11-01

    The effect of chronic aluminum (Al) administration on the phosphorous (Pi) metabolism of different target tissues was studied. Male Wistar rats received aluminum lactate for 3 months (5.75 mg/kg bodyweight of Al, i.p., three times per week). The animals were studied at the end of the 1st, 2nd and 3rd month of treatment. They were housed individually in metabolic cages for 4 days to study Pi and calcium (Ca) balance. Daily food and water intakes were recorded for all animals and urine and feces were collected for Pi and calcium assays. After 3 months the Pi intestinal absorption and the Pi deposition in bone were studied using 32Pi. Another group of rats was treated daily for 7 days with calcitriol (0.08 microg/kg body weight in sesame oil, i.p.) and the Pi balance was studied for the last 4 days. The results indicated that chronic administration of Al affected simultaneously the Pi and calcium balance, with a significant diminution of calcium and increased Pi accretion in bones, together with a diminution in the intestinal absorption of Pi. The treatment of the rats with calcitriol promoted a normalized Pi balance in Al treated rats. These findings suggest that Al could modify the Pi metabolism acting directly on intestine, kidney and bone, or indirectly through possible changes in the levels of vitamin D3.

  12. Physiological optimization underlies growth rate-independent chlorophyll-specific gross and net primary production.

    PubMed

    Halsey, Kimberly H; Milligan, Allen J; Behrenfeld, Michael J

    2010-02-01

    Characterization of physiological variability in phytoplankton photosynthetic efficiencies is one of the greatest challenges in assessing ocean net primary production (NPP) from remote sensing of surface chlorophyll (Chl). Nutrient limitation strongly influences phytoplankton intracellular pigmentation, but its impact on Chl-specific NPP (NPP(*)) is debated. We monitored six indices of photosynthetic activity in steady-state Dunaliella tertiolecta cultures over a range of nitrate-limited growth rates (μ), including photosynthetic efficiency of PSII (F(v)/F(m)), O(2)-based gross and net production, 20 min and 24 h carbon assimilation, and carbon- and μ-based NPP. Across all growth rates, O(2)-based Chl-specific gross primary production (GPP(*)(O(2))), NPP(*), and F(v)/F(m) were constant. GPP(*)(O(2)) was 3.3 times greater than NPP(*). In stark contrast, Chl-specific short-term C fixation showed clear linear dependence on μ, reflecting differential allocation of photosynthate between short-lived C products and longer-term storage products. Indeed, (14)C incorporation into carbohydrates was five times greater in cells growing at 1.2 day(-1) than 0.12 day(-1). These storage products are catabolized for ATP and reductant generation within the period of a cell cycle. The relationship between Chl-specific gross and net O(2) production, short-term (14)C-uptake, NPP(*), and growth rate reflects cellular-level regulation of fundamental metabolic pathways in response to nutrient limitation. We conclude that growth rate-dependent photosynthate metabolism bridges the gap between gross and net production and resolves a controversial question regarding nutrient limitation effects on primary production measures.

  13. Estimating Aboveground Net Primary Productivity of Black Spruce along a Climatic Gradient in the Boreal Forest.

    NASA Astrophysics Data System (ADS)

    Bhatti, J.; Varem-Sanders, T.; Bouriaud, O.

    2005-12-01

    Net primary productivity (NPP) is the difference between carbon assimilation by photosynthesis and plant respiration quantifies the rate at which carbon is accumulated in the living vegetation. The ability to measure net primary productivity (NPP) over a period of years using relatively inexpensive methods can be a tremendous asset when assessing the forest response to climate change. This project investigates and evaluates a new comprehensive method of estimating multi-decadal historical black spruce productivity using biomass stocks and tree ring width measurements along a climatic gradient. Black spruce aboveground NPP was calculated for even aged stands along Boreal Forest Transect Case Study (BFTCS) with similar soil and fertility characteristics. Biomass functions were modified using local DBH-height functions to determine tree level with Dbh as the sole predictor. Above ground net primary productivity was estimated from the stand level change in biomass with measured litter production rate on these sites. Tree biomass increment and litter production increases from Central Saskatchewan at the southern limit of the boreal forest where the climate is warm and dry up to Thompson (Northern Manitoba) where the climate is wetter and colder. Aboveground NPP for mature stands ranges from 671 to 1567 kg C ha-1 yr-1. Both at the southern boreal sites and northern boreal sites, the tree productivity was highly sensitivity to climate variability. The younger mixed black spruce stands are considerably more productive than older pure stands. Litter production is a major component and accounts for 30 to 60% of aboveground NPP. Practical robust estimation of aboveground NPP using tree ring measurement offers the potential for application over large spatial and temporal scale.

  14. Distribution of plankton lipids and their role in the biological transformation of Antarctic primary production

    NASA Astrophysics Data System (ADS)

    Mayzaud, P.; Errhif, A.; Bedo, A.

    1998-11-01

    Production and transfer of lipid through the Antarctic food web is reviewed for the Indian Ocean sector. The slow settling fine particles showed a marked inter-annual variability in biochemical composition with an increase in lipid content as % organic carbon. Comparison of the fatty acid spectra of different size categories of organic particles indicated that fine particles are dominated by saturated, monoenoic and branched acids, while larger material (50-100 μm, 200-500 μm net collected fractions) displayed a signature dominated by polyunsaturated acids. Zooplankton taxa displayed different strategies of lipid accumulation. Lipid content was highest in Thysanoessa macrura females and copepodite stages of Calanus propinquus. Relatively low levels were recorded for juveniles and male stages of euphausiids. Reserve lipids varied with species: C. propinquus showed equal content of triglycerides and wax esters, T. macrura showed a dominance of wax esters and Euphausia superba and Themisto gaudichaudii accumulated only triglycerides. Computed as carbon equivalent and integrated over 200 m, lipids in slow settling particles represented 22.6% of annual primary production. Similar computation with mesozooplankton and E. superba data on biomass and population structure from several summer cruises indicated values of carbon accumulation as lipid reserves and egg production of 4.2 and 0.1% of annual primary production for copepods and 4.4 and 3.8% for E. superba. When all trophic levels are considered, the overall mean exceeded 30% of annual primary production.

  15. Sea-ice algal primary production and nitrogen uptake rates off East Antarctica

    NASA Astrophysics Data System (ADS)

    Roukaerts, Arnout; Cavagna, Anne-Julie; Fripiat, François; Lannuzel, Delphine; Meiners, Klaus M.; Dehairs, Frank

    2016-09-01

    Antarctic pack ice comprises about 90% of the sea ice in the southern hemisphere and plays an important structuring role in Antarctic marine ecosystems, yet measurements of ice algal primary production and nitrogen uptake rates remain scarce. During the early austral spring of 2012, measurements for primary production rates and uptake of two nitrogen substrates (nitrate and ammonium) were conducted at 5 stations in the East Antarctic pack ice (63-66°S, 115-125°E). Carbon uptake was low (3.52 mg C m-2 d-1) but a trend of increased production was observed towards the end of the voyage suggesting pre-bloom conditions. Significant snow covers reaching, up to 0.8 m, induced strong light limitation. Two different regimes were observed in the ice with primarily nitrate based 'new' production (f-ratio: 0.80-0.95) at the bottom of the ice cover, due to nutrient-replete conditions at the ice-water interface, and common for pre-bloom conditions. In the sea-ice interior, POC:PN ratios (20-70) and higher POC:Chl a ratios suggested the presence of large amounts of detrital material trapped in the ice and here ammonium was the prevailing nitrogen substrate. This suggests that most primary production in the sea-ice interior was regenerated and supported by a microbial food web, recycling detritus.

  16. Release of primary microplastics from consumer products to wastewater in the Netherlands.

    PubMed

    van Wezel, Annemarie; Caris, Inez; Kools, Stefan A E

    2016-07-01

    The authors estimate the release of primary microplastics from consumer products-cosmetics and personal care products, cleaning agents, and paint and coatings-via sewage effluent as an expected relevant route to the marine environment. Total estimated concentrations in the 3 scenarios are 0.2 μg/L, 2.7 μg/L, and 66 μg/L in sewage-treatment plant (STP) effluent, respectively. All product categories relevantly contribute. Predicted concentrations are compared with reported actual concentrations in STP effluents. Environ Toxicol Chem 2016;35:1627-1631. © 2015 SETAC.

  17. Invariable biomass-specific primary production of taxonomically discrete picoeukaryote groups across the Atlantic Ocean.

    PubMed

    Grob, Carolina; Hartmann, Manuela; Zubkov, Mikhail V; Scanlan, Dave J

    2011-12-01

    Oceanic photosynthetic picoeukaryotes (< 3 µm) are responsible for > 40% of total primary production at low latitudes such as the North-Eastern tropical Atlantic. In the world ocean, warmed by climate changes, the expected gradual shift towards smaller primary producers could render the role of photosynthetic picoeukaryotes even more important than they are today. Little is still known, however, about how the taxonomic composition of this highly diverse group affects primary production at the basin scale. Here, we combined flow cytometric cell sorting, NaH¹⁴CO₃ radiotracer incubations and class-specific fluorescence in situ hybridization (FISH) probes to determine cell- and biomass-specific inorganic carbon fixation rates and taxonomic composition of two major photosynthetic picoeukaryote groups on a ∼7500-km-long latitudinal transect across the Atlantic Ocean (Atlantic Meridional Transect, AMT19). We show that even though larger cells have, on average, cell-specific CO₂ uptake rates ∼5 times higher than the smaller ones, the average biomass-specific uptake is statistically similar for both groups. On the other hand, even at a high taxonomic level, i.e. class, the contributions to both groups by Prymnesiophyceae, Chrysophyceae and Pelagophyceae are significantly different (P < 0.001 in all cases). We therefore conclude that these group's carbon fixation rates are independent of the taxonomic composition of photosynthetic picoeukaryotes across the Atlantic Ocean. Because the above applies across different oceanic regions the diversity changes seem to be a secondary factor determining primary production.

  18. A multi-sensor remote sensing approach for measuring primary production from space

    NASA Technical Reports Server (NTRS)

    Gautier, Catherine

    1989-01-01

    It is proposed to develop a multi-sensor remote sensing method for computing marine primary productivity from space, based on the capability to measure the primary ocean variables which regulate photosynthesis. The three variables and the sensors which measure them are: (1) downwelling photosynthetically available irradiance, measured by the VISSR sensor on the GOES satellite, (2) sea-surface temperature from AVHRR on NOAA series satellites, and (3) chlorophyll-like pigment concentration from the Nimbus-7/CZCS sensor. These and other measured variables would be combined within empirical or analytical models to compute primary productivity. With this proposed capability of mapping primary productivity on a regional scale, we could begin realizing a more precise and accurate global assessment of its magnitude and variability. Applications would include supplementation and expansion on the horizontal scale of ship-acquired biological data, which is more accurate and which supplies the vertical components of the field, monitoring oceanic response to increased atmospheric carbon dioxide levels, correlation with observed sedimentation patterns and processes, and fisheries management.

  19. The Influence of Sea Ice on Primary Production in the Southern Ocean: A Satellite Perspective

    NASA Technical Reports Server (NTRS)

    Smith, Walker O., Jr.; Comiso, Josefino C.

    2007-01-01

    Sea ice in the Southern Ocean is a major controlling factor on phytoplankton productivity and growth, but the relationship is modified by regional differences in atmospheric and oceanographic conditions. We used the phytoplankton biomass (binned at 7-day intervals), PAR and cloud cover data from SeaWiFS, ice concentrations data from SSM/I and AMSR-E, and sea-surface temperature data from AVHRR, in combination with a vertically integrated model to estimate primary productivity throughout the Southern Ocean (south of 60"s). We also selected six areas within the Southern Ocean and analyzed the variability of the primary productivity and trends through time, as well as the relationship of sea ice to productivity. We found substantial interannual variability in productivity from 1997 - 2005 in all regions of the Southern Ocean, and this variability appeared to be driven in large part by ice dynamics. The most productive regions of Antarctic waters were the continental shelves, which showed the earliest growth, the maximum biomass, and the greatest areal specific productivity. In contrast, no large, sustained blooms occurred in waters of greater depth (> 1,000 m). We suggest that this is due to the slightly greater mixed layer depths found in waters off the continental shelf, and that the interactive effects of iron and irradiance (that is, increased iron requirements in low irradiance environments) result in the limitation of phytoplankton biomass over large regions of the Southern Ocean.

  20. Dynamics of interleukin-21 production during the clinical course of primary and secondary dengue virus infections.

    PubMed

    Vivanco-Cid, H; Maldonado-Rentería, M J; Sánchez-Vargas, L A; Izaguirre-Hernández, I Y; Hernández-Flores, K G; Remes-Ruiz, R

    2014-09-01

    Previous studies have revealed the clinical relevance of pro-inflammatory cytokine production during dengue virus (DENV) infections. In this study, we evaluated the production of interleukin-21 (IL-21), a key soluble mediator mainly produced by CD4+ T cells. The aim of this study was to investigate the role of IL-21 production during the clinical course of primary and secondary DENV infections and the potential association of IL-21 serum levels with the disease pathogenesis. Blood samples from DENV-infected patients were collected on different days after the onset of symptoms. Patients were classified according to their phase of disease (acute vs. convalescent phases), the type of infection (primary vs. secondary), and the clinical severity of their disease (dengue fever (DF) vs. dengue hemorrhagic fever (DHF)). IL-21 levels were measured using a quantitative capture ELISA assay. The levels of IL-21 were significantly elevated in the disease group compared with the control group. IL-21 was detected in primary and secondary DENV infections, with a significantly higher concentration in the convalescent phase of primary infections. IL-21 levels were significantly higher in patients with secondary acute DHF infections when compared with those with secondary acute DF infection. There was a relationship between the elevated serum levels of IL-21 and the production of DENV-specific IgM and IgG antibodies. Taking together, our results show for the first time the involvement of IL-21 during the clinical course of DENV infections. We speculate that IL-21 may play a protective role in the context of the convalescent phase of primary infections and the acute phase of secondary infections.

  1. Annual primary production: Patterns and mechanisms of change in a nutrient-rich tidal ecosystem

    USGS Publications Warehouse

    Jassby, Alan D.; Cloern, James E.; Cole, B.E.

    2002-01-01

    Although nutrient supply often underlies long-term changes in aquatic primary production, other regulatory processes can be important. The Sacramento-San Joaquin River Delta, a complex of tidal waterways forming the landward portion of the San Francisco Estuary, has ample nutrient supplies, enabling us to examine alternate regulatory mechanisms over a 21-yr period. Delta-wide primary productivity was reconstructed from historical water quality data for 1975–1995. Annual primary production averaged 70 g C m−2, but it varied by over a factor of five among years. At least four processes contributed to this variability: (1) invasion of the clam Potamocorbula amurensis led to a persistent decrease in phytoplankton biomass (chlorophyll a) after 1986; (2) a long-term decline in total suspended solids—probably at least partly because of upstream dam construction—increased water transparency and phytoplankton growth rate; (3) river inflow, reflecting climate variability, affected biomass through fluctuations in flushing and growth rates through fluctuations in total suspended solids; and (4) an additional pathway manifesting as a long-term decline in winter phytoplankton biomass has been identified, but its genesis is uncertain. Overall, the Delta lost 43% in annual primary production during the period. Given the evidence for food limitation of primary consumers, these findings provide a partial explanation for widespread Delta species declines over the past few decades. Turbid nutrient-rich systems such as the Delta may be inherently more variable than other tidal systems because certain compensatory processes are absent. Comparisons among systems, however, can be tenuous because conclusions about the magnitude and mechanisms of variability are dependent on length of data record.  

  2. Method using selected carbons to react with Al2O and Al vapors in the carbothermic production of aluminum

    SciTech Connect

    Fruehan, Richard J.; Li, Yun; Carkin, Gerald

    2005-02-01

    In a method for recovering Al from an off-gas (3,4) produced during carbothermic reduction of aluminum utilizing at least one smelter (1,2), the off-gas (3,4) is directed to an enclosed reactor (5) which is fed a supply of wood charcoal (7) having a porosity of from about 50 vol. % to 85 vol. % and an average pore diameter of from about 0.05 .mu.m to about 2.00 .mu.m, where the wood charcoal (7) contacts the off-gas (3,4) to produce at least Al.sub.4 C.sub.3 (6), which is passed back to the smelter (1,2).

  3. Climate change decouples oceanic primary and export productivity and organic carbon burial

    NASA Astrophysics Data System (ADS)

    Lopes, Cristina; Kucera, Michal; Mix, Alan C.

    2015-01-01

    Understanding responses of oceanic primary productivity, carbon export, and burial to climate change is essential for model-based projection of biological feedbacks in a high-CO2 world. Here we compare estimates of productivity based on the composition of fossil diatom floras with organic carbon burial off Oregon in the Northeast Pacific across a large climatic transition at the last glacial termination. Although estimated primary productivity was highest during the Last Glacial Maximum, carbon burial was lowest, reflecting reduced preservation linked to low sedimentation rates. A diatom size index further points to a glacial decrease (and deglacial increase) in the fraction of fixed carbon that was exported, inferred to reflect expansion, and contraction, of subpolar ecosystems that today favor smaller plankton. Thus, in contrast to models that link remineralization of carbon to temperature, in the Northeast Pacific, we find dominant ecosystem and sea floor control such that intervals of warming climate had more efficient carbon export and higher carbon burial despite falling primary productivity.

  4. Assessing the impact of urbanization on regional net primary productivity in Jiangyin County, China.

    PubMed

    Xu, C; Liu, M; An, S; Chen, J M; Yan, P

    2007-11-01

    Urbanization is one of the most important aspects of global change. The process of urbanization has a significant impact on the terrestrial ecosystem carbon cycle. The Yangtze Delta region has one of the highest rates of urbanization in China. In this study, carried out in Jiangyin County as a representative region within the Yangtze Delta, land use and land cover changes were estimated using Landsat TM and ETM+ imagery. With these satellite data and the BEPS process model (Boreal Ecosystem Productivity Simulator), the impacts of urbanization on regional net primary productivity (NPP) and annual net primary production were assessed for 1991 and 2002. Landsat-based land cover maps in 1991 and 2002 showed that urban development encroached large areas of cropland and forest. Expansion of residential areas and reduction of vegetated areas were the major forms of land transformation in Jiangyin County during this period. Mean NPP of the total area decreased from 818 to 699 gCm(-2)yr(-1) during the period of 1991 to 2002. NPP of cropland was only reduced by 2.7% while forest NPP was reduced by 9.3%. Regional annual primary production decreased from 808 GgC in 1991 to 691 GgC in 2002, a reduction of 14.5%. Land cover changes reduced regional NPP directly, and the increasing intensity and frequency of human-induced disturbance in the urbanized areas could be the main reason for the decrease in forest NPP.

  5. Relationships between primary production and irradiance in coral reef algal communities

    SciTech Connect

    Not Available

    1985-07-01

    Shallow water algal turf communities are the major primary producers on coral reefs. High rates of primary production are maintained despite extremely high light intensities and exposure to ultraviolet wavelengths. The relationships between the light intensity and primary production in these assemblages are typical of algae adapted to a high light environment (low ..cap alpha.. (initial slope), high I/sub k/ (saturating light intensity), and high I/sub c/ (compensation point light intensity)). Seasonal variations in algal standing crop due to herbivory and daylength result in some characteristic photoadaptive changes in ..cap alpha.. I/sub k/, and I/sub c/ and changes in Pnet/sub max/ rates (maximum net photosynthetic rate achieved at light saturation) on both a chlorophyll ..cap alpha.. and an areal basis. Exposure to UV wavelength results in significantly higher respiration rates but no changes in ..cap alpha.., Pnet/sub max/, or I/sub k/, when compared with these parameters for the same algal communities incubated at the same light intensities without UV wavelengths. The apparent lack of photoinhibition in these algae allows calculation of the daily integrated production from the P vs. I parameters. This integrated production is highest in July (3.1 +/- 0.2 g C m/sup -2/d/sup -1/) and is reduced by 30% from this maximum in December (2.1 +/- 0.1 g C m/sup -2/d/sup -1/).

  6. Efficiency of chlorophyll in gross primary productivity: A proof of concept and application in crops.

    PubMed

    Gitelson, Anatoly A; Peng, Yi; Viña, Andrés; Arkebauer, Timothy; Schepers, James S

    2016-08-20

    One of the main factors affecting vegetation productivity is absorbed light, which is largely governed by chlorophyll. In this paper, we introduce the concept of chlorophyll efficiency, representing the amount of gross primary production per unit of canopy chlorophyll content (Chl) and incident PAR. We analyzed chlorophyll efficiency in two contrasting crops (soybean and maize). Given that they have different photosynthetic pathways (C3 vs. C4), leaf structures (dicot vs. monocot) and canopy architectures (a heliotrophic leaf angle distribution vs. a spherical leaf angle distribution), they cover a large spectrum of biophysical conditions. Our results show that chlorophyll efficiency in primary productivity is highly variable and responds to various physiological and phenological conditions, and water availability. Since Chl is accessible through non-destructive, remotely sensed techniques, the use of chlorophyll efficiency for modeling and monitoring plant optimization patterns is practical at different scales (e.g., leaf, canopy) and under widely-varying environmental conditions. Through this analysis, we directly related a functional characteristic, gross primary production with a structural characteristic, canopy chlorophyll content. Understanding the efficiency of the structural characteristic is of great interest as it allows explaining functional components of the plant system. PMID:27374843

  7. Microbial primary production on an Arctic glacier is insignificant in comparison with allochthonous organic carbon input.

    PubMed

    Stibal, Marek; Tranter, Martyn; Benning, Liane G; Rehák, Josef

    2008-08-01

    Cryoconite holes are unique freshwater environments on glacier surfaces, formed when solar-heated dark debris melts down into the ice. Active photoautotrophic microorganisms are abundant within the holes and fix inorganic carbon due to the availability of liquid water and solar radiation. Cryoconite holes are potentially important sources of organic carbon to the glacial ecosystem, but the relative magnitudes of autochthonous microbial primary production and wind-borne allochthonous organic matter brought are unknown. Here, we compare an estimate of annual microbial primary production in 2006 on Werenskioldbreen, a Svalbard glacier, with the organic carbon content of cryoconite debris. There is a great disparity between annual primary production (4.3 mug C g(-1) year(-1)) and the high content of organic carbon within the debris (1.7-4.5%, equivalent to 8500-22 000 mug C g(-1) debris). Long-term accumulation of autochthonous organic matter is considered unlikely due to ablation dynamics and the surface hydrology of the glacier. Rather, it is more likely that the majority of the organic matter on Werenskioldbreen is allochthonous. Hence, although glacier surfaces can be a significant source of organic carbon for glacial environments on Svalbard, they may be reservoirs rather than oases of high productivity. PMID:18430008

  8. Efficiency of chlorophyll in gross primary productivity: A proof of concept and application in crops.

    PubMed

    Gitelson, Anatoly A; Peng, Yi; Viña, Andrés; Arkebauer, Timothy; Schepers, James S

    2016-08-20

    One of the main factors affecting vegetation productivity is absorbed light, which is largely governed by chlorophyll. In this paper, we introduce the concept of chlorophyll efficiency, representing the amount of gross primary production per unit of canopy chlorophyll content (Chl) and incident PAR. We analyzed chlorophyll efficiency in two contrasting crops (soybean and maize). Given that they have different photosynthetic pathways (C3 vs. C4), leaf structures (dicot vs. monocot) and canopy architectures (a heliotrophic leaf angle distribution vs. a spherical leaf angle distribution), they cover a large spectrum of biophysical conditions. Our results show that chlorophyll efficiency in primary productivity is highly variable and responds to various physiological and phenological conditions, and water availability. Since Chl is accessible through non-destructive, remotely sensed techniques, the use of chlorophyll efficiency for modeling and monitoring plant optimization patterns is practical at different scales (e.g., leaf, canopy) and under widely-varying environmental conditions. Through this analysis, we directly related a functional characteristic, gross primary production with a structural characteristic, canopy chlorophyll content. Understanding the efficiency of the structural characteristic is of great interest as it allows explaining functional components of the plant system.

  9. Climate change decouples oceanic primary and export productivity and organic carbon burial

    PubMed Central

    Lopes, Cristina; Kucera, Michal; Mix, Alan C.

    2015-01-01

    Understanding responses of oceanic primary productivity, carbon export, and burial to climate change is essential for model-based projection of biological feedbacks in a high-CO2 world. Here we compare estimates of productivity based on the composition of fossil diatom floras with organic carbon burial off Oregon in the Northeast Pacific across a large climatic transition at the last glacial termination. Although estimated primary productivity was highest during the Last Glacial Maximum, carbon burial was lowest, reflecting reduced preservation linked to low sedimentation rates. A diatom size index further points to a glacial decrease (and deglacial increase) in the fraction of fixed carbon that was exported, inferred to reflect expansion, and contraction, of subpolar ecosystems that today favor smaller plankton. Thus, in contrast to models that link remineralization of carbon to temperature, in the Northeast Pacific, we find dominant ecosystem and sea floor control such that intervals of warming climate had more efficient carbon export and higher carbon burial despite falling primary productivity. PMID:25453073

  10. Stability of nicotinate and dodecyl sulfate in a Lewis acidic ionic liquid for aluminum electroplating and characterization of their degradation products.

    PubMed

    Kosmus, Patrick; Steiner, Oliver; Goessler, Walter; Gollas, Bernhard; Fauler, Gisela

    2016-04-01

    Plating bath additives are essential for optimization of the morphology of electroplated layers. The ionic liquid 1-ethyl-3-methylimidazolium (EMIM) chloride plus 1.5 mol equivalents of AlCl3 has great potential for electroplating of aluminum. In this study, the chemical and electrochemical stability of the additives EMIM-nicotinate and sodium dodecyl sulfate and their effect on the stability of EMIM was investigated and analyzed. Nicotinate and its electrochemical decomposition product β-picoline could be detected and we show with a single HPLC-UV-MS method that EMIM is not affected by the decomposition of this additive. An adapted standard HPLC-UV-MS method together with GC-MS and ion chromatography was used to analyze the decomposition products of SDS and possible realkylation products of EMIM. Several volatile medium and short chain-length alkanes as well as sulfate ions have been found as decomposition products of SDS. Alkenium ions formed as intermediates during the decomposition of SDS realkylate EMIM to produce mono- up to pentasubstituted alkyl-imidazoles. A reaction pathway involving Wagner-Meerwein rearrangements and Friedel-Crafts alkylations has been suggested to account for the formation of the detected products.

  11. Stability of nicotinate and dodecyl sulfate in a Lewis acidic ionic liquid for aluminum electroplating and characterization of their degradation products.

    PubMed

    Kosmus, Patrick; Steiner, Oliver; Goessler, Walter; Gollas, Bernhard; Fauler, Gisela

    2016-04-01

    Plating bath additives are essential for optimization of the morphology of electroplated layers. The ionic liquid 1-ethyl-3-methylimidazolium (EMIM) chloride plus 1.5 mol equivalents of AlCl3 has great potential for electroplating of aluminum. In this study, the chemical and electrochemical stability of the additives EMIM-nicotinate and sodium dodecyl sulfate and their effect on the stability of EMIM was investigated and analyzed. Nicotinate and its electrochemical decomposition product β-picoline could be detected and we show with a single HPLC-UV-MS method that EMIM is not affected by the decomposition of this additive. An adapted standard HPLC-UV-MS method together with GC-MS and ion chromatography was used to analyze the decomposition products of SDS and possible realkylation products of EMIM. Several volatile medium and short chain-length alkanes as well as sulfate ions have been found as decomposition products of SDS. Alkenium ions formed as intermediates during the decomposition of SDS realkylate EMIM to produce mono- up to pentasubstituted alkyl-imidazoles. A reaction pathway involving Wagner-Meerwein rearrangements and Friedel-Crafts alkylations has been suggested to account for the formation of the detected products. PMID:26864607

  12. Estimating the Capacity of Gross Primary Production from Global Observation Satellite

    NASA Astrophysics Data System (ADS)

    Muramatsu, Kanako; Soyama, Noriko; Thanyaparaneedkul, Juthasinee; Furumi, Shinobu; Daigo, Motomasa

    2012-07-01

    Estimation of Gross Primary Production with high accuracy is important for understanding the carbon cycle. For estimating gross primary production, photosynthesis process was considers into two parts. One is the capacity and another is the reduction which is influenced by environmental conditions such as weather conditions of vapor pressure difference and soil moisture. The capacity estimation part is reported in this conference. For a leaf, it is well known photosynthesis capacity is mainly depend on amount of chlorophyll and enzyme. Chlorophyll contents reflect the color of a leaf. Since we focus on the chlorophyll contents for estimating the capacity of the gross primary production. It was reported by J. Thanyapraneedkul (2012) that vegetation index of the ratio of green band and near infrared was linear relationship with chlorophyll contents of a leaf, and was a linear relationship with the maximum photosynthesis at light saturation of light response curve with less stress conditions using flux data. The index is suitable for global observing satellite, because the spectral bands are available. Using the index and empirical relationship developed by J. Thanyapraneedkul, the light response curve with less stress can be estimated from the vegetation index. In this study, firstly, the global distribution of the index was studied. The regions of high index value in winter time were correspond to tropical rainforest. Next, the capacity of gross primary production was estimated using the light response curve using the index. The GPP capacity of the almost all regions was higher than MODIS GPP. For the tropical rain forest regions, the GPP capacity value was similar with MODIS GPP product.

  13. Microbial Primary Productivity in Hydrothermal Vent Chimneys at Middle Valley, Juan de Fuca Ridge

    NASA Astrophysics Data System (ADS)

    Olins, H. C.; Rogers, D.; Frank, K. L.; Girguis, P. R.; Vidoudez, C.

    2012-12-01

    Chemosynthetic primary productivity supports hydrothermal vent ecosystems, but the extent of that productivity has not been well measured. To examine the role that environmental temperature plays in controlling carbon fixation rates, and to assess the degree to which microbial community composition, in situ geochemistry, and mineralogy influence carbon fixation, we conducted a series of shipboard incubations across a range of temperatures (4, 25, 50 and 90°C) and at environmentally relevant geochemical conditions using material recovered from three hydrothermal vent chimneys in the Middle Valley hydrothermal vent field (Juan de Fuca Ridge). Net rates of carbon fixation (CFX) were greatest at lower temperatures, and were similar among structures. Rates did not correlate with the mineralogy or the geochemical composition of the high temperature fluids at each chimney. No obvious patterns of association were observed between carbon fixation rates and microbial community composition. Abundance of selected functional genes related to different carbon fixation pathway exhibited striking differences among the three study sites, but did not correlate with rates. Natural carbon isotope ratios implicate the Calvin Benson Bassham Cycle as the dominant mechanism of primary production in these systems, despite the abundance of genes related to other pathways (and presumably some degree of activity). Together these data reveal that primary productivity by endolithic communities does not exhibit much variation among these chimneys, and further reveal that microbial activity cannot easily be related to mineralogical and geochemical assessments that are made at a coarser scale. Indeed, the relationships between carbon fixation rates and community composition/functional gene abundance were also likely obfuscated by differences in scale at which these measurements were made. Regardless, these data reveal the degree to which endolithic, anaerobic carbon fixation contributes to

  14. Influence of sea ice on primary production in the Southern Ocean: A satellite perspective

    NASA Astrophysics Data System (ADS)

    Smith, Walker O.; Comiso, Josefino C.

    2008-05-01

    Sea ice in the Southern Ocean is a major controlling factor on phytoplankton productivity, but the relationship is modified by regional differences in atmospheric and oceanographic conditions. We used the phytoplankton biomass, photosynthetically active radiation (PAR), and cloud cover data from Sea-viewing Wide Field of View Sensor (SeaWiFS), ice concentrations data from Special Sensor Microwave Imager (SSM/I) and Advanced Microwave Scanning Radiometer-EOS (AMSR-E), sea-surface temperature data from advanced very high resolution radiometer (AVHRR), and a vertically integrated model to estimate primary productivity south of 60°S. We also selected six areas within the Southern Ocean and analyzed the variability of the primary productivity and trends through time. We found substantial interannual variability in productivity from 1997 to 2005 in all regions of the Southern Ocean, and this variability appeared to be driven in large part by ice dynamics. The most productive regions of Antarctic waters were the continental shelves, and no sustained blooms occurred in waters of greater depth (>1000 m). We suggest that this is due to the slightly greater mixed layer depths found in waters off the continental shelf, and that the interactive effects of iron and irradiance result in the limitation of phytoplankton biomass over large regions of the Southern Ocean. Annual productivity of the Southern Ocean averaged 23.65 g C m-2 a-1, but yearly means for the years between 1998 and 2004 ranged from 22.10 to 25.49 g C m-2 d-1, respectively. Annual primary productivity over the entire Southern Ocean appears to have increased significantly since 1998, and much of this increase was confined to the months of January and February. Causes for this trend are presently unclear.

  15. Primary production in a tropical large lake: the role of phytoplankton composition.

    PubMed

    Darchambeau, F; Sarmento, H; Descy, J-P

    2014-03-01

    Phytoplankton biomass and primary production in tropical large lakes vary at different time scales, from seasons to centuries. We provide a dataset made of 7 consecutive years of phytoplankton biomass and production in Lake Kivu (Eastern Africa). From 2002 to 2008, bi-weekly samplings were performed in a pelagic site in order to quantify phytoplankton composition and biomass, using marker pigments determined by HPLC. Primary production rates were estimated by 96 in situ (14)C incubations. A principal component analysis showed that the main environmental gradient was linked to a seasonal variation of the phytoplankton assemblage, with a clear separation between diatoms during the dry season and cyanobacteria during the rainy season. A rather wide range of the maximum specific photosynthetic rate (PBm) was found, ranging between 1.15 and 7.21 g carbong(-1)chlorophyll ah(-1), and was best predicted by a regression model using phytoplankton composition as an explanatory variable. The irradiance at the onset of light saturation (Ik) ranged between 91 and 752 μE m(-2)s(-1) and was linearly correlated with the mean irradiance in the mixed layer. The inter-annual variability of phytoplankton biomass and production was high, ranging from 53 to 100 mg chlorophyll am(-2) (annual mean) and from 143 to 278 g carbon m(-2)y(-1), respectively. The degree of seasonal mixing determined annual production, demonstrating the sensitivity of tropical lakes to climate variability. A review of primary production of other African great lakes allows situating Lake Kivu productivity in the same range as that of lakes Tanganyika and Malawi, even if mean phytoplankton biomass was higher in Lake Kivu.

  16. Ecosystem allometry: the scaling of nutrient stocks and primary productivity across plant communities.

    PubMed

    Kerkhoff, Andrew J; Enquist, Brian J

    2006-04-01

    A principal challenge in ecology is to integrate physiological function (e.g. photosynthesis) across a collection of individuals (e.g. plants of different species) to understand the functioning of the entire ensemble (e.g. primary productivity). The control that organism size exerts over physiological and ecological function suggests that allometry could be a powerful tool for scaling ecological processes across levels of organization. Here we use individual plant allometries to predict how nutrient content and productivity scale with total plant biomass (phytomass) in whole plant communities. As predicted by our model, net primary productivity as well as whole community nitrogen and phosphorus content all scale allometrically with phytomass across diverse plant communities, from tropical forest to arctic tundra. Importantly, productivity data deviate quantitatively from the theoretically derived prediction, and nutrient productivity (production per unit nutrient) of terrestrial plant communities decreases systematically with increasing total phytomass. These results are consistent with the existence of pronounced competitive size hierarchies. The previously undocumented generality of these 'ecosystem allometries' and their basis in the structure and function of individual plants will likely provide a useful quantitative framework for research linking plant traits to ecosystem processes.

  17. Primary production and nutrients in a tropical macrotidal estuary, Darwin Harbour, Australia

    NASA Astrophysics Data System (ADS)

    Burford, M. A.; Alongi, D. M.; McKinnon, A. D.; Trott, L. A.

    2008-09-01

    Tropical estuaries are under increasing pressure worldwide from human impacts, but are poorly studied compared with temperate systems. This study examined a tropical macrotidal estuary, Darwin Harbour, in northern Australia, using a combination of direct measurements and literature values to determine the main sources of primary production and the sources of nutrients supporting growth. The main source of primary production was calculated to be the extensive area of fringing mangroves and resulted in a net autotrophic system ( PG: R = 2.1). Much of the carbon in the mangrove forests appears to be retained within the forests or respired, as the water column was also net autotrophic despite the carbon inputs. Phytoplankton were the second largest primary producer on a whole-of-harbour basis, with low biomass constrained by light and nutrient availability. The phytoplankton were likely to be nitrogen (N) limited, based on low N:phosphorus (P) ratios, low dissolved bioavailable N concentrations (ammonium (NH 4+), nitrate (NO 3-), urea), and evidence that phytoplankton growth in bioassays was stimulated by NH 4+ addition. The largest new source of N to the system was from the ocean due to higher N concentrations in the incoming tides than the outgoing tides. Atmospheric inputs via N fixation on the intertidal mudflats and subtidal sediments were substantially lower. The rivers feeding into the harbour and sewage were minor N inputs. Nitrogen demand by primary producers was high relative to available N inputs, suggesting that N recycling within the water column and mangrove forests must be important processes. Darwin Harbour is adjacent to the rapidly growing urban area of Darwin city, but overall there is no evidence of anthropogenic nutrient inputs having substantial effects on primary production in Darwin Harbour.

  18. A Virtual Aluminum Reduction Cell

    NASA Astrophysics Data System (ADS)

    Zhang, Hongliang; Zhou, Chenn Q.; Wu, Bing; Li, Jie

    2013-11-01

    The most important component in the aluminum industry is the aluminum reduction cell; it has received considerable interests and resources to conduct research to improve its productivity and energy efficiency. The current study focused on the integration of numerical simulation data and virtual reality technology to create a scientifically and practically realistic virtual aluminum reduction cell by presenting complex cell structures and physical-chemical phenomena. The multiphysical field simulation models were first built and solved in ANSYS software (ANSYS Inc., Canonsburg, PA, USA). Then, the methodology of combining the simulation results with virtual reality was introduced, and a virtual aluminum reduction cell was created. The demonstration showed that a computer-based world could be created in which people who are not analysis experts can see the detailed cell structure in a context that they can understand easily. With the application of the virtual aluminum reduction cell, even people who are familiar with aluminum reduction cell operations can gain insights that make it possible to understand the root causes of observed problems and plan design changes in much less time.

  19. Remote sensing of biomass and annual net aerial primary productivity of a salt marsh

    NASA Technical Reports Server (NTRS)

    Hardisky, M. A.; Klemas, V.; Daiber, F. C.; Roman, C. T.

    1984-01-01

    Net aerial primary productivity is the rate of storage of organic matter in above-ground plant issues exceeding the respiratory use by the plants during the period of measurement. It is pointed out that this plant tissue represents the fixed carbon available for transfer to and consumption by the heterotrophic organisms in a salt marsh or the estuary. One method of estimating annual net aerial primary productivity (NAPP) required multiple harvesting of the marsh vegetation. A rapid nondestructive remote sensing technique for estimating biomass and NAPP would, therefore, be a significant asset. The present investigation was designed to employ simple regression models, equating spectral radiance indices with Spartina alterniflora biomass to nondestructively estimate salt marsh biomass. The results of the study showed that the considered approach can be successfully used to estimate salt marsh biomass.

  20. Oceanic Primary Production: Estimation by Remote Sensing at Local and Regional Scales

    NASA Astrophysics Data System (ADS)

    Platt, Trevor; Sathyendranath, Shubha

    1988-09-01

    Satellites provide the only avenue by which marine primary production can be studied at ocean-basin scales. With maps of chlorophyll distribution derived from remotely sensed data on ocean color as input, deduction of a suitable algorithm for primary production is a problem in applied plant physiology. An algorithm is proposed that combines a spectral and angular model of submarine light with a model of the spectral response of algal photosynthesis. To apply the algorithm at large horizontal scale, a dynamic biogeography is needed for the physiological rate parameters and the biological structure of the water column. Fieldwork to obtain this type of data should be undertaken so that the use of satellite data in modern biological oceanography may be optimized.

  1. Oceanic primary production: estimation by remote sensing at local and regional scales.

    PubMed

    Platt, T; Sathyendranath, S

    1988-09-23

    Satellites provide the only avenue by which marine primary production can be studied at ocean-basin scales. With maps of chlorophyll distribution derived from remotely sensed data on ocean color as input, deduction of a suitable algorithm for primary production is a problem in applied plant physiology. An algorithm is proposed that combines a spectral and angular model of submarine light with a model of the spectral response of algal photosynthesis. To apply the algorithm at large horizontal scale, a dynamic biogeography is needed for the physiological rate parameters and the biological structure of the water column. Fieldwork to obtain this type of data should be undertaken so that the use of satellite data in modern biological oceanography may be optimized.

  2. Comparing the impact of the 2003 and 2010 heatwaves on Net Primary Production in Europe

    NASA Astrophysics Data System (ADS)

    Bastos, Ana; Gouveia, Célia M.; Trigo, Ricardo M.; Running, Steve W.

    2013-04-01

    Climate variability is known to influence primary productivity on land ecosystems (Nemani et al., 2003). In particular, extreme climatic events such as major droughts and heatwaves are known to have severe impact on primary productivity and, therefore, to affect significantly the carbon dioxide uptake by land ecosystems at regional (Ciais et al., 2005) or even global scale (Zhao and Running, 2010). In the last decade, Europe was struck by two outstanding heatwaves, the 2003 event in Western Europe and the recent 2010 episode over Eastern Europe. Both were characterised by record breaking temperatures at the daily, weekly, monthly and seasonal scales, although the amplitude and spatial extent of the 2010 mega-heatwave surpassed the 2003 event (Barriopedro et al., 2011). This work aims to assess the influence of both mega-heatwaves on yearly Net Primary Production (NPP) and seasonal Net Photosynthesis (NP), which corresponds to the difference between Gross Primary Production and maintenance respiration. The work relies on yearly NPP and monthly NP data derived from satellite imagery obtained from MODIS (Moderate Resolution Imaging Spectroradiometer) sensor at 1km spatial resolution. Data were selected for the period between 2000 and 2011 over a region extending from 34.6N to 73.5N and 12.1W to 46.8E, covering Eurasia. In 2010 very low primary production anomalies are observed over a very large area in Eastern Europe, at the monthly, seasonal and yearly scale. In western Russia, yearly NPP anomalies fall below 50% of average. These widespread negative anomalous values of NP fields over the western Russia region match the patterns of very high temperature values combined with below-average precipitation, at the seasonal (summer) scale. Moreover, the impact of the heatwave is not only evident at the regional level but also at the wider continental (European) scale and is significantly more extensive and intense than the corresponding heatwave of 2003 in Western Europe

  3. Subsurface Aluminum Nitride Formation in Iron-Aluminum Alloys

    NASA Astrophysics Data System (ADS)

    Bott, June H.

    Transformation-induced plasticity (TRIP) steels containing higher amounts of aluminum than conventional steels are ideal for structural automotive parts due to their mechanical properties. However, the aluminum tends to react with any processing environment at high temperatures and therefore presents significant challenges during manufacturing. One such challenge occurs during secondary cooling, reheating, and hot-rolling and is caused by a reaction with nitrogen-rich atmospheres wherein subsurface aluminum nitride forms in addition to internal and external oxides. The nitrides are detrimental to mechanical properties and cause surface cracks. It is important to understand how these nitrides and oxides form and their consequences for the quality of steel products. This study looks at model iron-aluminum (up to 8 wt.% aluminum) alloys and uses confocal laser scanning microscopy, x-ray diffraction, scanning electron microscopy with energy dispersive x-ray spectrometry, and transmission electron microscopy to study the effect of various conditions on the growth and development of these precipitates in a subsurface oxygen-depleted region. By using model alloys and controlling the experimental atmosphere, this study is able to understand some of the more fundamental materials science behind aluminum nitride formation in aluminum-rich iron alloys and the relationship between internal nitride and oxide precipitation and external oxide scale morphology and composition. The iron-aluminum alloys were heated in N2 atmospheres containing oxygen impurities. It was found that nitrides formed when bulk aluminum content was below 8 wt.% when oxygen was sufficiently depleted due to the internal oxidation. In the samples containing 1 wt.% aluminum, the depth of the internal oxide and nitride zones were in agreement with a diffusion-based model. Increasing aluminum content to 3 and 5 wt% had the effects of modifying the surface-oxide scale composition and increasing its continuity

  4. Primary production and bacterial carbon metabolism around South Shetland Islands in the Southern Ocean

    NASA Astrophysics Data System (ADS)

    Teira, Eva; Mouriño-Carballido, Beatriz; Martínez-García, Sandra; Sobrino, Cristina; Ameneiro, Julia; Hernández-León, Santiago; Vázquez, Elsa

    2012-11-01

    Phytoplankton and bacterioplankton dynamics were studied around South Shetland Islands (Antarctica) with special emphasis on the Drake Passage region, during austral summer, in order to expand our knowledge on the coupling between the autotrophic and heterotrophic microbial plankton compartments in polar ecosystems. In addition, we directly estimated bacterial growth efficiency in the Drake Passage with the aim of better constraining total bacterial carbon utilization in this important polar ecosystem. Integrated chlorophyll-a concentration (21-86 mg m-2), primary production rates (0.7-19.3 mg C m-3 d-1) and mean water-column photochemical efficiency (0.24-0.60) were significantly correlated with Si* tracer (r2=0.55, 0.46 and 0.64, respectively), which indirectly points to iron as the major limiting factor for phytoplankton growth in the area. Bacterial production was considerably low (0.002-0.3 mg C m-3 d-1) and was best explained by chlorophyll-a concentration, protein-like fluorescence of dissolved organic matter and temperature (r2=0.53, p<0.001). Water temperature appeared to influence bacterial activity when organic substrate availability is high. Bacterial production accounted on average for only 3.9% of co-occurring primary production, which has been frequently interpreted as an indicator of the marked uncoupling between bacteria and phytoplankton in cold waters. However, using the experimentally derived mean bacterial growth efficiency for the photic zone (6.1±1.3%) the bacterial carbon demand represented on average 63±18% of concomitant primary production, similar to what is found in warmer productive waters. Thus, our study suggests that bacterioplankton and phytoplankton appear to be connected in this polar area.

  5. Using Carbon Isotopes in Cenozoic Soil Carbonates to Quantify Primary Productivity from Mid-Latitude Regions

    NASA Astrophysics Data System (ADS)

    Caves, J. K.; Kramer, S. H.; Ibarra, D. E.; Chamberlain, C. P.

    2015-12-01

    The carbon isotope composition of pedogenic carbonates (δ13Ccarb) from paleosols has been extensively used as a proxy to estimate atmospheric pCO2 over the Phanerozoic. However, a number of other factors - including the concentration of plant-respired CO2 and the isotopic composition of both atmospheric and plant-respired carbon - influence the δ13C of pedogenic carbonates. For example, δ13Ccarb records from the mid-latitudes in central Asia and western North America show increasing trends in δ13Ccarb despite decreasing pCO2 during the late Cenozoic, which suggests that other factors play an important role in determining the isotopic composition of pedogenic carbonates. Instead, we suggest that these records are primarily recording changes in primary productivity rather than changes in atmospheric pCO2 and therefore propose a novel use of paleosol carbonate records to understand paleo-ecosystem dynamics. Here, we compile existing paleosol carbonate records, and present three new records from Wyoming, to estimate soil respiration and primary productivity in western North America during the Paleogene and early Neogene. We observe both an overall increase in δ13Ccarb after the early Eocene, and spatially heterogeneous δ13Ccarb values across western US basins. We combine this δ13Ccarb data with compilations of atmospheric pCO2 to estimate soil respiration and plant productivity. The long-term increase in δ13Ccarb indicates a decrease in plant productivity as conditions became more arid across much of the western US, congruent with both records of regional uplift and of global cooling. Furthermore, significant spatial heterogeneity in δ13Ccarb indicates that regional factors, such as the presence of paleolakes and/or local paleotopography may have provided a second-order control on local and regional productivity. Thus, our results provide a first-order estimate linking changes in primary productivity with regional tectonics and global climatic change.

  6. Global human appropriation of net primary production doubled in the 20th century

    PubMed Central

    Krausmann, Fridolin; Erb, Karl-Heinz; Gingrich, Simone; Haberl, Helmut; Bondeau, Alberte; Gaube, Veronika; Lauk, Christian; Plutzar, Christoph; Searchinger, Timothy D.

    2013-01-01

    Global increases in population, consumption, and gross domestic product raise concerns about the sustainability of the current and future use of natural resources. The human appropriation of net primary production (HANPP) provides a useful measure of human intervention into the biosphere. The productive capacity of land is appropriated by harvesting or burning biomass and by converting natural ecosystems to managed lands with lower productivity. This work analyzes trends in HANPP from 1910 to 2005 and finds that although human population has grown fourfold and economic output 17-fold, global HANPP has only doubled. Despite this increase in efficiency, HANPP has still risen from 6.9 Gt of carbon per y in 1910 to 14.8 GtC/y in 2005, i.e., from 13% to 25% of the net primary production of potential vegetation. Biomass harvested per capita and year has slightly declined despite growth in consumption because of a decline in reliance on bioenergy and higher conversion efficiencies of primary biomass to products. The rise in efficiency is overwhelmingly due to increased crop yields, albeit frequently associated with substantial ecological costs, such as fossil energy inputs, soil degradation, and biodiversity loss. If humans can maintain the past trend lines in efficiency gains, we estimate that HANPP might only grow to 27–29% by 2050, but providing large amounts of bioenergy could increase global HANPP to 44%. This result calls for caution in refocusing the energy economy on land-based resources and for strategies that foster the continuation of increases in land-use efficiency without excessively increasing ecological costs of intensification. PMID:23733940

  7. Ocean Primary Production Estimates from Terra MODIS and Their Dependency on Satellite Chlorophyll Alpha Algorithms

    NASA Technical Reports Server (NTRS)

    Essias, Wayne E.; Abbott, Mark; Carder, Kendall; Campbell, Janet; Clark, Dennis; Evans, Robert; Brown, Otis; Kearns, Ed; Kilpatrick, Kay; Balch, W.

    2003-01-01

    Simplistic models relating global satellite ocean color, temperature, and light to ocean net primary production (ONPP) are sensitive to the accuracy and limitations of the satellite estimate of chlorophyll and other input fields, as well as the primary productivity model. The standard MODIS ONPP product uses the new semi-analytic chlorophyll algorithm as its input for two ONPP indexes. The three primary MODIS chlorophyll Q estimates from MODIS, as well as the SeaWiFS 4 chlorophyll product, were used to assess global and regional performance in estimating ONPP for the full mission, but concentrating on 2001. The two standard ONPP algorithms were examined with 8-day and 39 kilometer resolution to quantify chlorophyll algorithm dependency of ONPP. Ancillary data (MLD from FNMOC, MODIS SSTD1, and PAR from the GSFC DAO) were identical. The standard MODIS ONPP estimates for annual production in 2001 was 59 and 58 GT C for the two ONPP algorithms. Differences in ONPP using alternate chlorophylls were on the order of 10% for global annual ONPP, but ranged to 100% regionally. On all scales the differences in ONPP were smaller between MODIS and SeaWiFS than between ONPP models, or among chlorophyll algorithms within MODIS. Largest regional ONPP differences were found in the Southern Ocean (SO). In the SO, application of the semi-analytic chlorophyll resulted in not only a magnitude difference in ONPP (2x), but also a temporal shift in the time of maximum production compared to empirical algorithms when summed over standard oceanic areas. The resulting increase in global ONPP (6-7 GT) is supported by better performance of the semi-analytic chlorophyll in the SO and other high chlorophyll regions. The differences are significant in terms of understanding regional differences and dynamics of ocean carbon transformations.

  8. Impacts of Temperature on Primary Productivity and Respiration in Naturally Structured Macroalgal Assemblages

    PubMed Central

    Tait, Leigh W.; Schiel, David R.

    2013-01-01

    Rising global temperatures caused by human-mediated change has already triggered significant responses in organismal physiology, distribution and ecosystem functioning. Although the effects of rising temperature on the physiology of individual organisms are well understood, the effect on community-wide processes has remained elusive. The fixation of carbon via primary productivity is an essential ecosystem function and any shifts in the balance of primary productivity and respiration could alter the carbon balance of ecosystems. Here we show through a series of tests that respiration of naturally structured algal assemblages in southern New Zealand greatly increases with rising temperature, with implications for net primary productivity (NPP). The NPP of in situ macroalgal assemblages was minimally affected by natural temperature variation, possibly through photo-acclimation or temperature acclimation responses, but respiration rates and compensating irradiance were negatively affected. However, laboratory experiments testing the impacts of rising temperature on several photosynthetic parameters showed a decline in NPP, increasing respiration rates and increasing compensating irradiance. The respiration Q10 of laboratory assemblages (the difference in metabolic rates over 10°C) averaged 2.9 compared to a Q10 of 2 often seen in other autotrophs. However, gross primary productivity (GPP) Q10 averaged 2, indicating that respiration was more severely affected by rising temperature. Furthermore, combined high irradiance and high temperature caused photoinhibition in the laboratory, and resulted in 50% lower NPP at high irradiance. Our study shows that communities may be more severely affected by rising global temperatures than would be expected by responses of individual species. In particular, enhanced respiration rates and rising compensation points have the potential to greatly affect the carbon balance of macroalgal assemblages through declines in sub-canopy NPP

  9. Effects of global brightening on primary production and hypoxia in Ise Bay, Japan

    NASA Astrophysics Data System (ADS)

    Tanaka, Yoji; Kanno, Ariyo; Shinohara, Ryuichiro

    2014-07-01

    In many parts of the world, annual mean surface solar radiation (SSR) has undergone significant decadal changes; however, its effect on the coastal water environment has not been investigated. This study investigates the effects of changes in the SSR on hypoxia and the primary production of phytoplankton in a eutrophic bay in Japan (Ise Bay), where the annual SSR increased by 13.3% from 1980 to 2010. We numerically simulated the hydrodynamics and ecosystem of 2010 using a three-dimensional model (case O). We used this model to simulate the case where SSR was reduced by 10% (case A) and estimated the effect of an increase in SSR from the difference between case O and case A. With the 10% increase in SSR, the primary production in the bay increased by only 2.8%. This limited increase was the result of the negative effects by the nonlinearity of the light limitation function (including the photoinhibition) and the limitation in PO4-P availability and a significant positive effect by the increased water temperature. Similarly, the overall volume of hypoxic water increased, and in August, it increased by 5.8%. This is because water temperature and biomass such as phytoplankton increased with the increase in SSR; consequently, all oxygen consumption terms such as biological respiration also increased. These results imply that recent global brightening has the potential to amplify the primary production and hypoxia in a eutrophic bay.

  10. Connectedness of land use, nutrients, primary production, and fish assemblages in oxbow lakes

    USGS Publications Warehouse

    Miranda, Leandro E.; Andrews, Caroline S.; Kroger, Robert

    2013-01-01

    We explored the strength of connectedness among hierarchical system components associated with oxbow lakes in the alluvial valley of the Lower Mississippi River. Specifically, we examined the degree of canonical correlation between land use (agriculture and forests), lake morphometry (depth and size), nutrients (total nitrogen and total phosphorus), primary production (chlorophyll-a), and various fish assemblage descriptors. Watershed (p < 0.01) and riparian (p = 0.02) land use, and lake depth (p = 0.05) but not size (p = 0.28), were associated with nutrient concentrations. In turn, nutrients were associated with primary production (p < 0.01), and primary production was associated with sunfish (Centrarchidae) assemblages (p < 0.01) and fish biodiversity (p = 0.08), but not with those of other taxa and functional guilds. Multiple chemical and biological components of oxbow lake ecosystems are connected to landscape characteristics such as land use and lake depth. Therefore, a top-down hierarchical approach can be useful in developing management and conservation plans for oxbow lakes in a region impacted by widespread landscape changes due to agriculture.

  11. The Primary and Secondary Production of Germanium: A Life-Cycle Assessment of Different Process Alternatives

    NASA Astrophysics Data System (ADS)

    Robertz, Benedicte; Verhelle, Jensen; Schurmans, Maarten

    2015-02-01

    Germanium is a semiconducting metalloid element used in optical fibers, catalysis, infrared optics, solar cells, and light-emitting diodes. The need for Ge in these markets is considered to increase by a steady ~1% on a yearly basis. Its economic importance, coupled with the identified supply risks, has led to the classification of germanium as a critical raw material within Europe. Since the early 1950s, Umicore Electro-Optic Materials has supplied germanium-based materials solutions to its markets around the world. Umicore extracts germanium from a wide range of refining and recycling feeds. The main objectives of this study were to quantify the potential environmental impacts of the production of germanium from production scraps from the photovoltaic industry and to compare them with the potential impacts of the primary production of germanium from coal. The data related to the secondary production are Umicore-specific data. Environmental impact scores have been calculated for the impact categories recommended by the International reference life cycle data system. The comparison of the primary and secondary production highlights the benefit linked to the recycling of metals.

  12. Estimators of primary production for interpretation of remotely sensed data on ocean color

    NASA Technical Reports Server (NTRS)

    Platt, Trevor; Sathyendranath, Shubha

    1993-01-01

    The theoretical basis is explained for some commonly used estimators of daily primary production in a vertically uniform water column. These models are recast into a canonical form, with dimensionless arguments, to facilitate comparison with each other and with an analytic solution. The limitations of each model are examined. The values of the photoadaptation parameter I(k) observed in the ocean are analyzed, and I(k) is used as a scale to normalize the surface irradiance. The range of this scaled irradiance is presented. An equation is given for estimation of I(k) from recent light history. It is shown how the models for water column production can be adapted for estimation of the production in finite layers. The distinctions between model formulation, model implementation and model evaluation are discussed. Recommendations are given on the choice of algorithm for computation of daily production according to the degree of approximation acceptable in the result.

  13. Scaleable Clean Aluminum Melting Systems

    SciTech Connect

    Han, Q.; Das, S.K.

    2008-02-15

    The project entitled 'Scaleable Clean Aluminum Melting Systems' was a Cooperative Research and Development Agreements (CRADAs) between Oak Ridge National Laboratory (ORNL) and Secat Inc. The three-year project was initially funded for the first year and was then canceled due to funding cuts at the DOE headquarters. The limited funds allowed the research team to visit industrial sites and investigate the status of using immersion heaters for aluminum melting applications. Primary concepts were proposed on the design of furnaces using immersion heaters for melting. The proposed project can continue if the funding agency resumes the funds to this research. The objective of this project was to develop and demonstrate integrated, retrofitable technologies for clean melting systems for aluminum in both the Metal Casting and integrated aluminum processing industries. The scope focused on immersion heating coupled with metal circulation systems that provide significant opportunity for energy savings as well as reduction of melt loss in the form of dross. The project aimed at the development and integration of technologies that would enable significant reduction in the energy consumption and environmental impacts of melting aluminum through substitution of immersion heating for the conventional radiant burner methods used in reverberatory furnaces. Specifically, the program would couple heater improvements with furnace modeling that would enable cost-effective retrofits to a range of existing furnace sizes, reducing the economic barrier to application.

  14. Partial decoupling of primary productivity from upwelling in the California Current system

    NASA Astrophysics Data System (ADS)

    Renault, Lionel; Deutsch, Curtis; McWilliams, James C.; Frenzel, Hartmut; Liang, Jun-Hong; Colas, François

    2016-07-01

    Coastal winds and upwelling of deep nutrient-rich water along subtropical eastern boundaries yield some of the ocean's most productive ecosystems. Simple indices of coastal wind strength have been extensively used to estimate the timing and magnitude of biological productivity on seasonal and interannual timescales and underlie the prediction that anthropogenic climate warming will increase the productivity by making coastal winds stronger. The effect of wind patterns on regional net primary productivity is not captured by such indices and is poorly understood. Here we present evidence, using a realistic model of the California Current system and satellite measurements, that the observed slackening of the winds near the coast has little effect on near-shore phytoplankton productivity despite a large reduction in upwelling velocity. On the regional scale the wind drop-off leads to substantially higher production even when the total upwelling rate remains the same. This partial decoupling of productivity from upwelling results from the impact of wind patterns on alongshore currents and the eddies they generate. Our results imply that productivity in eastern boundary upwelling systems will be better predicted from indices of the coastal wind that account for its offshore structure.

  15. The Effect of Improving Primary Care Depression Management on Employee Absenteeism and Productivity A Randomized Trial

    PubMed Central

    Rost, Kathryn; Smith, Jeffrey L.; Dickinson, Miriam

    2005-01-01

    Objective: To test whether an intervention to improve primary care depression management significantly improves productivity at work and absenteeism over 2 years. Setting and Subjects: Twelve community primary care practices recruiting depressed primary care patients identified in a previsit screening. Research Design: Practices were stratified by depression treatment patterns before randomization to enhanced or usual care. After delivering brief training, enhanced care clinicians provided improved depression management over 24 months. The research team evaluated productivity and absenteeism at baseline, 6, 12, 18, and 24 months in 326 patients who reported full-or part-time work at one or more completed waves. Results: Employed patients in the enhanced care condition reported 6.1% greater productivity and 22.8% less absenteeism over 2 years. Consistent with its impact on depression severity and emotional role functioning, intervention effects were more observable in consistently employed subjects where the intervention improved productivity by 8.2% over 2 years at an estimated annual value of $1982 per depressed full-time equivalent and reduced absenteeism by 28.4% or 12.3 days over 2 years at an estimated annual value of $619 per depressed full-time equivalent. Conclusions: This trial, which is the first to our knowledge to demonstrate that improving the quality of care for any chronic disease has positive consequences for productivity and absenteeism, encourages formal cost-benefit research to assess the potential return-on-investment employers of stable workforces can realize from using their purchasing power to encourage better depression treatment for their employees. PMID:15550800

  16. A multi-sites analysis on the ozone effects on Gross Primary Production of European forests.

    PubMed

    Proietti, C; Anav, A; De Marco, A; Sicard, P; Vitale, M

    2016-06-15

    Ozone (O3) is both a greenhouse gas and a secondary air pollutant causing adverse impacts on forests ecosystems at different scales, from cellular to ecosystem level. Specifically, the phytotoxic nature of O3 can impair CO2 assimilation that, in turn affects forest productivity. This study aims to evaluate the effects of tropospheric O3 on Gross Primary Production (GPP) at 37 European forest sites during the time period 2000-2010. Due to the lack of carbon assimilation data at O3 monitoring stations (and vice-versa) this study makes a first attempt to combine high resolution MODIS Gross Primary Production (GPP) estimates and O3 measurement data. Partial Correlations, Anomalies Analysis and the Random Forests Analysis (RFA) were used to quantify the effects of tropospheric O3 concentration and its uptake on GPP and to evaluate the most important factors affecting inter-annual GPP changes. Our results showed, along a North-West/South-East European transect, a negative impact of O3 on GPP ranging from 0.4% to 30%, although a key role of meteorological parameters respect to pollutant variables in affecting GPP was found. In particular, meteorological parameters, namely air temperature (T), soil water content (SWC) and relative humidity (RH) are the most important predictors at 81% of test sites. Moreover, it is interesting to highlight a key role of SWC in the Mediterranean areas (Spanish, Italian and French test sites) confirming that, soil moisture and soil water availability affect vegetation growth and photosynthesis especially in arid or semi-arid ecosystems such as the Mediterranean climate regions. Considering the pivotal role of GPP in the global carbon balance and the O3 ability to reduce primary productivity of the forests, this study can help in assessing the O3 impacts on ecosystem services, including wood production and carbon sequestration. PMID:26971205

  17. Holocene primary productivity and the atmosphere/ocean linkage in the Gulf of Alaska

    NASA Astrophysics Data System (ADS)

    Addison, J. A.; Finney, B.; Anderson, L.; Barron, J. A.; Hayes, S. M.; Sliwinski, M.; Mix, A. C.

    2015-12-01

    Recent work in the temperate fjords of the Gulf of Alaska, located in the subarctic northeast Pacific Ocean, has demonstrated a positive link between modern atmosphere/ocean dynamics and accumulation of biogenic sediments during the last 100 years, where intensified Aleutian Low atmospheric pressure cell regimes correspond to peaks in export primary productivity (Addison et al., 2013). Here, this work is extended by examining the last 7500 years of biogenic sedimentation from marine sediment core EW0408-33JC (57.16°N, 135.36°W, 144 m water depth), which is constrained by 17 age-control points spaced every ~500 years. We use bromine (Br) intensities measured by core-scanning XRF with a 2-mm sampling resolution as a geochemical proxy for past primary productivity. These Br intensities are calibrated to organic Br concentrations using a combination of quantitative WD-XRF methods and synchrotron-radiation Br speciation studies, with cross-verification provided by low-resolution analyses of other productivity proxies, including biogenic silica (opal), total organic carbon (TOC), and organic matter δ13C ratios. Our findings indicate distinct centennial-to-millennial changes, with positive productivity excursions between 7500-7000, 6500-6000, 5000-3500, 2500-1500, and 1000-500 INTCAL13 yr BP. We compare the timing of these excursions against a compilation of marine and terrestrial paleoclimate records sensitive to forcing by the Aleutian Low to determine if the positive relationship between atmosphere/ocean dynamics and marine primary productivity has remained consistent over the last 7500 years. Other potential forcing mechanisms (e.g., solar insolation, irradiance) are also considered. Reference: Addison, J.A., Finney, B., Jaeger, J., Stoner, J., Norris, R., & Hangsterfer, A., 2013, Integrating satellite observations and modern climate measurements with the recent sedimentary record: an example from Southeast Alaska. JGR-Oceans, v. 118, 18 pgs.

  18. Size-fractionated dissolved primary production and carbohydrate composition of the coccolithophore Emiliania huxleyi

    NASA Astrophysics Data System (ADS)

    Borchard, C.; Engel, A.

    2014-11-01

    Extracellular release (ER) by phytoplankton is the major source of fresh dissolved organic carbon (DOC) in marine ecosystems and accompanies primary production during all growth phases. Little is known, so far, on size and composition of released molecules, and to which extent ER occurs passively, by leakage, or actively, by exudation. Here, we report on ER by the widespread and bloom-forming coccolithophore Emiliania huxleyi grown under steady state conditions in phosphorus controlled chemostats (N : P = 29, growth rate of μ = 0.2 d-1). 14C incubations were accomplished to determine primary production (PP), comprised by particulate (PO14C) and dissolved organic carbon (DO14C), and the concentration and composition of particulate combined carbohydrates (pCCHO), and of high molecular weight (>1 kDa, HMW) dissolved combined carbohydrates (dCCHO) as major components of ER. Information on size distribution of ER products was obtained by investigating distinct size classes (<0.40 μm, <1000 kDa, <100 kDa and <10 kDa) of DO14C and HMW-dCCHO. Our results revealed relatively low ER during steady state growth, corresponding to ∼4.5% of primary production, and similar ER rates for all size classes. Acidic sugars had a significant share on freshly produced pCCHO as well as on HMW-dCCHO. While pCCHO and the smallest size (<10 kDa) fraction of HMW-dCCHO exhibited a similar sugar composition, dominated by high percentages of glucose (74-80 Mol%), the composition of HMW-dCCHO size-classes >10 kDa was significantly different with higher Mol% of arabinose. Mol% of acidic sugars increased and Mol% glucose decreased with increasing size of HMW-dCCHO. We conclude that larger polysaccharides follow different production and release pathways than smaller molecules, potentially serving distinct ecological and biogeochemical functions.

  19. Fission product plateout and liftoff in the MHTGR primary system: A review

    SciTech Connect

    Wichner, R.P. )

    1991-04-01

    A review is presented of the technical basis for predicting radioactivity release resulting from depressurization of an MHTGR primary system. Consideration is restricted to so called dry events with no involvement of the steam system. The various types of deposition mechanisms effective for iodine, cesium, strontium, and silver are discussed in terms of their chemical characteristics and the nature of the materials in the primary system. Emphasis is given to iodine behavior, including means for estimating the quantity available for release, the types of plateout locations in the primary system, and the effect of dust on distribution and release. The behavior of fission products cesium, strontium, and silver in such accidents is presented qualitatively. A major part of the review deals with expected dust levels, types, and transport. Available information on the level and nature of dust in the HTGR primary system is reviewed. A summary is presented of dust deposition and liftoff mechanisms. It was concluded that recent approaches to dust liftoff modeling, based on turbulent burst concepts for removal from surfaces, probably offer advantages over the current shear ratio approach. This study concludes that iodine releases from dry depressurization events are likely to be extremely low, on the order of millicuries, due to a predictably low degree of chemical desorption, a low degree of dust liftoff, and a low involvement of iodine with dust. It was also concluded that deposition mechanisms controlling the distribution of fission product material in the primary system, and hence also controlling the degree of liftoff, depend strongly on the chemical nature of the individual elements. Therefore contrary to the current practice, both plateout and liftoff models should reflect those unique chemical and physical properties. 56 refs., 16 figs., 23 tabs.

  20. Electrometallurgical treatment of aluminum-based fuels.

    SciTech Connect

    Willit, J. L.

    1998-07-29

    We have successfully demonstrated aluminum electrorefining from a U-Al-Si alloy that simulates spent aluminum-based reactor fuel. The aluminum product contains less than 200 ppm uranium. All the results obtained have been in agreement with predictions based on equilibrium thermodynamics. We have also demonstrated the need for adequate stirring to achieve a low-uranium product. Most of the other process steps have been demonstrated in other programs. These include uranium electrorefining, transuranic fission product scrubbing, fission product oxidation, and product consolidation by melting. Future work will focus on the extraction of active metal and rare earth fission products by a molten flux salt and scale-up of the aluminum electrorefining.

  1. Uncoupling between dinitrogen fixation and primary productivity in the eastern Mediterranean Sea

    NASA Astrophysics Data System (ADS)

    Rahav, Eyal; Herut, Barak; Stambler, Noga; Bar-Zeev, Edo; Mulholland, Margaret R.; Berman-Frank, Ilana

    2013-03-01

    In the nitrogen (N)-impoverished photic zones of many oceanic regions, prokaryotic organisms fixing atmospheric dinitrogen (N2; diazotrophs) supply an essential source of new nitrogen and fuel primary production. We measured dinitrogen fixation and primary productivity (PP) during the thermally stratified summer period in different water regimes of the oligotrophic eastern Mediterranean Sea, including the Cyprus Eddy and the Rhodes Gyre. Low N2 fixation rates were measured (0.8-3.2 µmol N m-2 d-1) excluding 10-fold higher rates in the Rhodes Gyre and Cyprus Eddy (~20 µmol N m-2 d-1). The corresponding PP increased from east to west (200-2500 µmol C m-2 d-1), with relatively higher productivity recorded in the Rhodes Gyre and Cyprus Eddy (2150 and 2300 µmol C m-2 d-1, respectively). These measurements demonstrate that N2 fixation in the photic zone of the eastern Mediterranean Sea contributes only negligibly by direct inputs to PP (i.e., cyanobacterial diazotrophs) and is in fact uncoupled from PP. By contrast, N2 fixation is significantly coupled to bacterial productivity and to net heterotrophic areas, suggesting that heterotrophic N2 fixation may in fact be significant in this ultraoligotrophic system. This is further substantiated by the high N2 fixation rates we measured from aphotic depths and by the results of phylogenetic analysis in other studies showing an abundance of heterotrophic diazotrophs.

  2. Patterns of new versus recycled primary production in the terrestrial biosphere.

    PubMed

    Cleveland, Cory C; Houlton, Benjamin Z; Smith, W Kolby; Marklein, Alison R; Reed, Sasha C; Parton, William; Del Grosso, Stephen J; Running, Steven W

    2013-07-30

    Nitrogen (N) and phosphorus (P) availability regulate plant productivity throughout the terrestrial biosphere, influencing the patterns and magnitude of net primary production (NPP) by land plants both now and into the future. These nutrients enter ecosystems via geologic and atmospheric pathways and are recycled to varying degrees through the plant-soil-microbe system via organic matter decay processes. However, the proportion of global NPP that can be attributed to new nutrient inputs versus recycled nutrients is unresolved, as are the large-scale patterns of variation across terrestrial ecosystems. Here, we combined satellite imagery, biogeochemical modeling, and empirical observations to identify previously unrecognized patterns of new versus recycled nutrient (N and P) productivity on land. Our analysis points to tropical forests as a hotspot of new NPP fueled by new N (accounting for 45% of total new NPP globally), much higher than previous estimates from temperate and high-latitude regions. The large fraction of tropical forest NPP resulting from new N is driven by the high capacity for N fixation, although this varies considerably within this diverse biome; N deposition explains a much smaller proportion of new NPP. By contrast, the contribution of new N to primary productivity is lower outside the tropics, and worldwide, new P inputs are uniformly low relative to plant demands. These results imply that new N inputs have the greatest capacity to fuel additional NPP by terrestrial plants, whereas low P availability may ultimately constrain NPP across much of the terrestrial biosphere.

  3. The role of mesoscale eddies for primary production along the ice edge

    NASA Astrophysics Data System (ADS)

    Samuelsen, Annette

    2016-04-01

    The ice-edge is a favorable area for the generation of mesoscale eddies. Because of the high latitudes, these eddies are often order of 10 km, but have been observed up to 50 km. The physical surface manifestation can be remotely observed by SAR (Synthetic Aperture Radar), but the corresponding patterns of phytoplankton are hard to observe by ocean color because of the presence of ice and clouds. Because these eddies will transport fresh-water it is likely that they influence the stratification and thus the local blooming conditions. A regional model for the Fram Strait with resolution 3.5 km has been set up as a coupled physical-biogeochemical model, HYCOM-NORWECOM, nested into a 15-km basin-scale model for the North Atlantic and Arctic. The biogeochemical model represents nutrients, phytoplankton and zooplankton. The 3.5 km resolution model is adequate to resolve the largest eddies in the region, while smaller eddies and submesoscale processes are not resolved. Patches of higher primary production are present close to the ice edge, despite nutrient availability being comparable to adjacent regions. During late summer the biomass and primary production close to the ice edge is dominated by diatoms and closely follows the mesoscale structures. Here we investigate whether theses eddies play a role primarily in redistributing the water with high production and if the eddies themselves contribute to enhancement or reduction in the production.

  4. Diel periodicity of photosynthesis in polar phytoplankton: influence on primary production

    SciTech Connect

    Rivkin, R.B.; Putt, M.

    1987-11-27

    In the Southern Ocean, primary production estimated from seasonal chemical and geochemical changes is two to four times greater than the value calculated from carbon-14 uptake. Since carbon uptake had typically been measured only during midday incubation, the influence of diel periodicity of photosynthesis on daily productions was not considered. Phytoplankton from McMurdo Sound, Antarctica, exhibited distinct, but seasonally variable diel patterns of light-saturated and light-limited photosynthesis. Maximum photosynthetic capacity occurred about noon in early September, and its occurrence progressively shifted to about midnight by late October. This shift was accompanied by a concomitant phase shift in the occurrence of minimum photosynthetic capacity from midnight to midday. Daily production estimated from time-of-day corrected photosynthetic characteristics and from 24-hour incubations was 2.5 to 4 times greater than that predicted from 6-hour midday incubations. If similar diel periodicity in photosynthesis occurs in other polar oceans, primary production would be significantly higher than previously estimated from carbon-14 uptake measurements.

  5. The Puzzle of HCN in Comets: Is it both a Product and a Primary Species?

    NASA Astrophysics Data System (ADS)

    Mumma, Michael J.; Bonev, Boncho P.; Charnley, Steven B.; Cordiner, Martin A.; DiSanti, Michael A.; Gibb, Erika L.; Magee-Sauer, Karen; Paganini, Lucas; Villanueva, Geronimo L.

    2014-11-01

    Hydrogen cyanide has long been regarded as a primary volatile in comets, stemming from its presence in dense molecular cloud cores and its supposed storage in the cometary nucleus. Here, we examine the observational evidence for and against that hypothesis, and argue that HCN may also result from near-nucleus chemical reactions in the coma. The distinction (product vs. primary species) is important for multiple reasons: 1. HCN is often used as a proxy for water when the dominant species (H2O) is not available for simultaneous measurement, as at radio wavelengths. 2. HCN is one of the few volatile carriers of nitrogen accessible to remote sensing. If HCN is mainly a product species, its precursor becomes the more important metric for compiling a taxonomic classification based on nitrogen chemistry. 3. The stereoisomer HNC is now confirmed as a product species. Could reaction of a primary precursor (X-CN) with a hydrocarbon co-produce both HNC and HCN? 4. The production rate for CN greatly exceeds that of HCN in some comets, demonstrating the presence of another (more important) precursor of CN. Several puzzling lines of evidence raise issues about the origin of HCN: a. The production rates of HCN measured through rotational (radio) and vibrational (infrared) spectroscopy agree in some comets - in others the infrared rate exceeds the radio rate substantially. b. With its strong dipole moment and H-bonding character, HCN should be linked more strongly in the nuclear ice to other molecules with similar properties (H2O, CH3OH), but instead its spatial release in some comets seems strongly coupled to volatiles that lack a dipole moment and thus do not form H-bonds (methane, ethane). c. The nucleus-centered rotational temperatures measured for H2O and other species (C2H6, CH3OH) usually agree within error, but those for HCN are often slightly smaller. d. In comet ISON, ALMA maps of HCN and the dust continuum show a slight displacement 80 km) in the centroids. We will

  6. Modelling the seasonality of subsurface light and primary production in the Arabian Sea

    USGS Publications Warehouse

    Brock, John C.; Sathyendranath, Shubha; Platt, Trevor

    1993-01-01

    Seasonal changes in mixed-layer depth and phytoplankton biomass in the Arabian Sea are assessed with climatologies of ship-based hydrographic measurements and ocean-color observations from satellite.  At the close of the intermonsoons in November and especially May, the open Arabian Sea resembles the stereotypic, unperturbed tropical ocean, with a thin oligotrophic mixed layer and a pronounced subsurface chlorophyll maximum.  Both the northeast and southwest monsoons disrupt this typical tropical hydrography through mixed-layer deepening and eutrophication in the central and northern Arabian Sea.  Computations using a spectral model of light penetration suggest that seasonal changes in mixed-layer thickness and phytoplankton concentration result in pronounced fluctuations through the annual cycle in the radiant flux reaching the base of the mixed layer.  At the close of the fall and spring intermonsoons the base of the model euphotic zone is in the thermocline across all of the open Arabian Sea.  The euphotic zone appears to rise into the mixed layer of the northern Arabian Sea during both the winter and summer monsoons.  Strong seasonality in total primary production and its partitioning between the mixed layer and thermocline is predicted byb a photo-synthesis-irradiance model for a site in the western Arabian Sea (14.36° N, 57.38° E).  Modeled mixed-layer primary production depicts an intense peak for the southwest monsoon and a secondary northeast monsoon peak separated by intermonsoon period of low production.  During the fall and spring intermonsoons, in the presence of a subsurface clorophyll maximum, the model estimate of primary production in the thermocline exceeds that in the mixed layer.  Our model calculations suggest that the subsurface clorophyll maximum present in the Arabian Sea during the spring intermonsoon is a precursor of the regional, summer, phytoplankton bloom.

  7. Inter-annual Variability of Aboveground Net Primary Productivity in Regenerating Tropical Dry Forests

    NASA Astrophysics Data System (ADS)

    Powers, J. S.; Becknell, J. M.

    2015-12-01

    Globally, there are now more secondary forests regenerating following anthropogenic disturbance than primary forests. However, carbon dynamics in secondary tropical forests in general, and seasonally dry forests in particular, have not been as well studied as primary wet forests. Young, regenerating forests may be more sensitive to climatic variability than older forests because of their dynamic demographic rates. Similarly, seasonally dry tropical forests may be particularly sensitive to changes in precipitation, as tree growth is highly constrained by water availability. We examined how inter-annual variability in precipitation affected above-ground net primary productivity in chronosequences of dry forest in Costa Rica. Our sites included three forest cover types, whose distribution is linked to edaphic variation. Over our 6-yr dataset, annual rainfall varied from 1110 to 3040mm, with a 5-6 month dry season. ANPP ranged from 2.96 to 18.98 Mg ha-1 across sites that have been recovering for 7 to 67 years. Fine litter production dominated ANPP, and increased with forest age but not annual rainfall. By contrast, woody stem growth did not vary among forests that differed in age, but increased as a function of annual rainfall. These results differed by forest type. Lowland oak forests on low fertility soil had the lowest productivity and responses to rainfall, whereas forests on the highest fertility soils showed large increases in woody production with rainfall. Consistent with our expectation, younger forests on the intermediate soil type had higher variability in ANPP than older forests, but this was not significant for forests on the poor or high fertility soils. Our results highlight several important findings: 1) different components of ANPP vary in their responses to inter-annual variation in rainfall, 2) forest responses to climatic variability depend on species composition, which varies consistently with soil type in this landscape.

  8. Cadmium-isotopic evidence for increasing primary productivity during the Late Permian anoxic event

    NASA Astrophysics Data System (ADS)

    Georgiev, Svetoslav V.; Horner, Tristan J.; Stein, Holly J.; Hannah, Judith L.; Bingen, Bernard; Rehkämper, Mark

    2015-01-01

    Earth's most extreme extinction event near the end of the Late Permian decimated more than 90% of all extant marine species. Widespread and intensive oceanic anoxia almost certainly contributed to the catastrophe, though the driving mechanisms that sustained such conditions are still debated. Of particular interest is whether water column anoxia was a consequence of a 'stagnant ocean', or if it was controlled by increases in nutrient supply, primary productivity, and subsequent heterotrophic respiration. Testing these competing hypotheses requires deconvolving sedimentary/bottom water redox conditions from changes in surface water productivity in marine sediments. We address this issue by studying marine shales from East Greenland and the mid-Norwegian shelf and combining sedimentary redox proxies with cadmium-isotopic analyses. Sedimentary nitrogen-isotopic data, pyrite framboid analyses, and organic and inorganic shale geochemistry reveal sulfidic conditions with vigorous upwelling, and increasingly anoxic conditions with a strengthening upwelling in the Greenland and Norwegian sections, respectively. Detailed analysis of sedimentary metal budgets illustrates that Cd is primarily associated with organic carbon and records primary geochemical signatures, thus enabling reconstruction of surface water nutrient utilization. Cadmium-isotopic analyses of the authigenic shale fraction released by inverse aqua regia digestion yield an average δ114Cd110 of + 0.15 ± 0.01 ‰ (2 SE, n = 12; rel. NIST SRM 3108), indicative of incomplete surface water nutrient utilization up-section. The constant degree of nutrient utilization combined with strong upwelling requires increasing primary productivity - and not oceanic stagnation - to balance the larger nutrient fluxes to both study sites during the development of the Late Permian water column anoxia. Overall, our data illustrate that if bottom water redox and upwelling can be adequately constrained, Cd-isotopic analyses of

  9. Two hundred years of aluminum ... or is it aluminium?

    NASA Astrophysics Data System (ADS)

    Kvande, Halvor

    2008-08-01

    Two hundred years ago the word aluminum was used for the first time when a new metal was produced by the English chemist Sir Humphry Davy. Later work has shown that this metal was not pure, but rather an aluminum-iron alloy. This article commemorates the anniversary of aluminum production with a look back at the metal’s origins.

  10. 21 CFR 182.1131 - Aluminum sodium sulfate.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 3 2011-04-01 2011-04-01 false Aluminum sodium sulfate. 182.1131 Section 182.1131 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) FOOD... Substances § 182.1131 Aluminum sodium sulfate. (a) Product. Aluminum sodium sulfate. (b) Conditions of...

  11. 21 CFR 582.1127 - Aluminum ammonium sulfate.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 6 2014-04-01 2014-04-01 false Aluminum ammonium sulfate. 582.1127 Section 582.1127 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED... Additives § 582.1127 Aluminum ammonium sulfate. (a) Product. Aluminum ammonium sulfate. (b) Conditions...

  12. 21 CFR 582.1781 - Sodium aluminum phosphate.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Sodium aluminum phosphate. 582.1781 Section 582.1781 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED... Additives § 582.1781 Sodium aluminum phosphate. (a) Product. Sodium aluminum phosphate. (b) Conditions...

  13. 21 CFR 582.1127 - Aluminum ammonium sulfate.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 6 2012-04-01 2012-04-01 false Aluminum ammonium sulfate. 582.1127 Section 582.1127 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED... Additives § 582.1127 Aluminum ammonium sulfate. (a) Product. Aluminum ammonium sulfate. (b) Conditions...

  14. 21 CFR 182.1131 - Aluminum sodium sulfate.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 3 2014-04-01 2014-04-01 false Aluminum sodium sulfate. 182.1131 Section 182.1131...) SUBSTANCES GENERALLY RECOGNIZED AS SAFE Multiple Purpose GRAS Food Substances § 182.1131 Aluminum sodium sulfate. (a) Product. Aluminum sodium sulfate. (b) Conditions of use. This substance is...

  15. 21 CFR 182.1781 - Sodium aluminum phosphate.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 3 2012-04-01 2012-04-01 false Sodium aluminum phosphate. 182.1781 Section 182.1781 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED... Food Substances § 182.1781 Sodium aluminum phosphate. (a) Product. Sodium aluminum phosphate....

  16. 21 CFR 582.1781 - Sodium aluminum phosphate.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 6 2014-04-01 2014-04-01 false Sodium aluminum phosphate. 582.1781 Section 582.1781 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED... Additives § 582.1781 Sodium aluminum phosphate. (a) Product. Sodium aluminum phosphate. (b) Conditions...

  17. 21 CFR 182.2122 - Aluminum calcium silicate.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 3 2014-04-01 2014-04-01 false Aluminum calcium silicate. 182.2122 Section 182...) SUBSTANCES GENERALLY RECOGNIZED AS SAFE Anticaking Agents § 182.2122 Aluminum calcium silicate. (a) Product. Aluminum calcium silicate. (b) Tolerance. 2 percent. (c) Limitations, restrictions, or explanation....

  18. 21 CFR 182.1129 - Aluminum potassium sulfate.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Aluminum potassium sulfate. 182.1129 Section 182.1129 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED... Food Substances § 182.1129 Aluminum potassium sulfate. (a) Product. Aluminum potassium sulfate....

  19. 21 CFR 582.1131 - Aluminum sodium sulfate.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Aluminum sodium sulfate. 582.1131 Section 582.1131 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL... Additives § 582.1131 Aluminum sodium sulfate. (a) Product. Aluminum sodium sulfate. (b) Conditions of...

  20. 21 CFR 182.1131 - Aluminum sodium sulfate.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 3 2012-04-01 2012-04-01 false Aluminum sodium sulfate. 182.1131 Section 182.1131 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) FOOD... Substances § 182.1131 Aluminum sodium sulfate. (a) Product. Aluminum sodium sulfate. (b) Conditions of...

  1. 21 CFR 182.2122 - Aluminum calcium silicate.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 3 2012-04-01 2012-04-01 false Aluminum calcium silicate. 182.2122 Section 182.2122 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED....2122 Aluminum calcium silicate. (a) Product. Aluminum calcium silicate. (b) Tolerance. 2 percent....

  2. 21 CFR 582.1127 - Aluminum ammonium sulfate.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 6 2013-04-01 2013-04-01 false Aluminum ammonium sulfate. 582.1127 Section 582.1127 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED... Additives § 582.1127 Aluminum ammonium sulfate. (a) Product. Aluminum ammonium sulfate. (b) Conditions...

  3. 21 CFR 582.1129 - Aluminum potassium sulfate.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 6 2011-04-01 2011-04-01 false Aluminum potassium sulfate. 582.1129 Section 582.1129 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED... Additives § 582.1129 Aluminum potassium sulfate. (a) Product. Aluminum potassium sulfate. (b) Conditions...

  4. 21 CFR 582.1129 - Aluminum potassium sulfate.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Aluminum potassium sulfate. 582.1129 Section 582.1129 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED... Additives § 582.1129 Aluminum potassium sulfate. (a) Product. Aluminum potassium sulfate. (b) Conditions...

  5. 21 CFR 582.2122 - Aluminum calcium silicate.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 6 2012-04-01 2012-04-01 false Aluminum calcium silicate. 582.2122 Section 582.2122 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED....2122 Aluminum calcium silicate. (a) Product. Aluminum calcium silicate. (b) Tolerance. 2 percent....

  6. 21 CFR 582.1131 - Aluminum sodium sulfate.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 6 2014-04-01 2014-04-01 false Aluminum sodium sulfate. 582.1131 Section 582.1131 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL... Additives § 582.1131 Aluminum sodium sulfate. (a) Product. Aluminum sodium sulfate. (b) Conditions of...

  7. 21 CFR 582.2122 - Aluminum calcium silicate.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 6 2013-04-01 2013-04-01 false Aluminum calcium silicate. 582.2122 Section 582.2122 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED....2122 Aluminum calcium silicate. (a) Product. Aluminum calcium silicate. (b) Tolerance. 2 percent....

  8. 21 CFR 182.2122 - Aluminum calcium silicate.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 3 2013-04-01 2013-04-01 false Aluminum calcium silicate. 182.2122 Section 182.2122 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED....2122 Aluminum calcium silicate. (a) Product. Aluminum calcium silicate. (b) Tolerance. 2 percent....

  9. 21 CFR 182.1127 - Aluminum ammonium sulfate.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Aluminum ammonium sulfate. 182.1127 Section 182.1127 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED... Food Substances § 182.1127 Aluminum ammonium sulfate. (a) Product. Aluminum ammonium sulfate....

  10. 21 CFR 582.2122 - Aluminum calcium silicate.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Aluminum calcium silicate. 582.2122 Section 582.2122 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED....2122 Aluminum calcium silicate. (a) Product. Aluminum calcium silicate. (b) Tolerance. 2 percent....

  11. 21 CFR 582.1131 - Aluminum sodium sulfate.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 6 2011-04-01 2011-04-01 false Aluminum sodium sulfate. 582.1131 Section 582.1131 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL... Additives § 582.1131 Aluminum sodium sulfate. (a) Product. Aluminum sodium sulfate. (b) Conditions of...

  12. 21 CFR 182.1129 - Aluminum potassium sulfate.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 3 2013-04-01 2013-04-01 false Aluminum potassium sulfate. 182.1129 Section 182.1129 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED... Food Substances § 182.1129 Aluminum potassium sulfate. (a) Product. Aluminum potassium sulfate....

  13. 21 CFR 182.2122 - Aluminum calcium silicate.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 3 2011-04-01 2011-04-01 false Aluminum calcium silicate. 182.2122 Section 182.2122 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED....2122 Aluminum calcium silicate. (a) Product. Aluminum calcium silicate. (b) Tolerance. 2 percent....

  14. 21 CFR 582.1127 - Aluminum ammonium sulfate.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 6 2011-04-01 2011-04-01 false Aluminum ammonium sulfate. 582.1127 Section 582.1127 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED... Additives § 582.1127 Aluminum ammonium sulfate. (a) Product. Aluminum ammonium sulfate. (b) Conditions...

  15. 21 CFR 582.1781 - Sodium aluminum phosphate.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 6 2013-04-01 2013-04-01 false Sodium aluminum phosphate. 582.1781 Section 582.1781 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED... Additives § 582.1781 Sodium aluminum phosphate. (a) Product. Sodium aluminum phosphate. (b) Conditions...

  16. 21 CFR 582.1131 - Aluminum sodium sulfate.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 6 2012-04-01 2012-04-01 false Aluminum sodium sulfate. 582.1131 Section 582.1131 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL... Additives § 582.1131 Aluminum sodium sulfate. (a) Product. Aluminum sodium sulfate. (b) Conditions of...

  17. 21 CFR 182.1127 - Aluminum ammonium sulfate.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 3 2012-04-01 2012-04-01 false Aluminum ammonium sulfate. 182.1127 Section 182.1127 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED... Food Substances § 182.1127 Aluminum ammonium sulfate. (a) Product. Aluminum ammonium sulfate....

  18. 21 CFR 182.1127 - Aluminum ammonium sulfate.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 3 2014-04-01 2014-04-01 false Aluminum ammonium sulfate. 182.1127 Section 182...) SUBSTANCES GENERALLY RECOGNIZED AS SAFE Multiple Purpose GRAS Food Substances § 182.1127 Aluminum ammonium sulfate. (a) Product. Aluminum ammonium sulfate. (b) Conditions of use. This substance is...

  19. 21 CFR 182.1127 - Aluminum ammonium sulfate.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 3 2013-04-01 2013-04-01 false Aluminum ammonium sulfate. 182.1127 Section 182.1127 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED... Food Substances § 182.1127 Aluminum ammonium sulfate. (a) Product. Aluminum ammonium sulfate....

  20. 21 CFR 582.2122 - Aluminum calcium silicate.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 6 2014-04-01 2014-04-01 false Aluminum calcium silicate. 582.2122 Section 582.2122 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED....2122 Aluminum calcium silicate. (a) Product. Aluminum calcium silicate. (b) Tolerance. 2 percent....

  1. 21 CFR 582.1129 - Aluminum potassium sulfate.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 6 2014-04-01 2014-04-01 false Aluminum potassium sulfate. 582.1129 Section 582.1129 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED... Additives § 582.1129 Aluminum potassium sulfate. (a) Product. Aluminum potassium sulfate. (b) Conditions...

  2. 21 CFR 182.1129 - Aluminum potassium sulfate.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 3 2011-04-01 2011-04-01 false Aluminum potassium sulfate. 182.1129 Section 182.1129 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED... Food Substances § 182.1129 Aluminum potassium sulfate. (a) Product. Aluminum potassium sulfate....

  3. 21 CFR 582.1129 - Aluminum potassium sulfate.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 6 2013-04-01 2013-04-01 false Aluminum potassium sulfate. 582.1129 Section 582.1129 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED... Additives § 582.1129 Aluminum potassium sulfate. (a) Product. Aluminum potassium sulfate. (b) Conditions...

  4. 21 CFR 582.1781 - Sodium aluminum phosphate.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 6 2011-04-01 2011-04-01 false Sodium aluminum phosphate. 582.1781 Section 582.1781 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED... Additives § 582.1781 Sodium aluminum phosphate. (a) Product. Sodium aluminum phosphate. (b) Conditions...

  5. 21 CFR 582.1131 - Aluminum sodium sulfate.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 6 2013-04-01 2013-04-01 false Aluminum sodium sulfate. 582.1131 Section 582.1131 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL... Additives § 582.1131 Aluminum sodium sulfate. (a) Product. Aluminum sodium sulfate. (b) Conditions of...

  6. 21 CFR 182.1781 - Sodium aluminum phosphate.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 3 2013-04-01 2013-04-01 false Sodium aluminum phosphate. 182.1781 Section 182.1781 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED... Food Substances § 182.1781 Sodium aluminum phosphate. (a) Product. Sodium aluminum phosphate....

  7. 21 CFR 182.1131 - Aluminum sodium sulfate.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 3 2013-04-01 2013-04-01 false Aluminum sodium sulfate. 182.1131 Section 182.1131 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) FOOD... Substances § 182.1131 Aluminum sodium sulfate. (a) Product. Aluminum sodium sulfate. (b) Conditions of...

  8. 21 CFR 182.1781 - Sodium aluminum phosphate.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 3 2014-04-01 2014-04-01 false Sodium aluminum phosphate. 182.1781 Section 182...) SUBSTANCES GENERALLY RECOGNIZED AS SAFE Multiple Purpose GRAS Food Substances § 182.1781 Sodium aluminum phosphate. (a) Product. Sodium aluminum phosphate. (b) Conditions of use. This substance is...

  9. 21 CFR 182.1131 - Aluminum sodium sulfate.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Aluminum sodium sulfate. 182.1131 Section 182.1131 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) FOOD... Substances § 182.1131 Aluminum sodium sulfate. (a) Product. Aluminum sodium sulfate. (b) Conditions of...

  10. 21 CFR 582.1781 - Sodium aluminum phosphate.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 6 2012-04-01 2012-04-01 false Sodium aluminum phosphate. 582.1781 Section 582.1781 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED... Additives § 582.1781 Sodium aluminum phosphate. (a) Product. Sodium aluminum phosphate. (b) Conditions...

  11. 21 CFR 182.1781 - Sodium aluminum phosphate.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 3 2011-04-01 2011-04-01 false Sodium aluminum phosphate. 182.1781 Section 182.1781 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED... Food Substances § 182.1781 Sodium aluminum phosphate. (a) Product. Sodium aluminum phosphate....

  12. 21 CFR 582.1127 - Aluminum ammonium sulfate.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Aluminum ammonium sulfate. 582.1127 Section 582.1127 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED... Additives § 582.1127 Aluminum ammonium sulfate. (a) Product. Aluminum ammonium sulfate. (b) Conditions...

  13. 21 CFR 182.1129 - Aluminum potassium sulfate.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 3 2012-04-01 2012-04-01 false Aluminum potassium sulfate. 182.1129 Section 182.1129 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED... Food Substances § 182.1129 Aluminum potassium sulfate. (a) Product. Aluminum potassium sulfate....

  14. 21 CFR 582.2122 - Aluminum calcium silicate.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 6 2011-04-01 2011-04-01 false Aluminum calcium silicate. 582.2122 Section 582.2122 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED....2122 Aluminum calcium silicate. (a) Product. Aluminum calcium silicate. (b) Tolerance. 2 percent....

  15. 21 CFR 182.1781 - Sodium aluminum phosphate.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Sodium aluminum phosphate. 182.1781 Section 182.1781 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED... Food Substances § 182.1781 Sodium aluminum phosphate. (a) Product. Sodium aluminum phosphate....

  16. 21 CFR 182.1129 - Aluminum potassium sulfate.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 3 2014-04-01 2014-04-01 false Aluminum potassium sulfate. 182.1129 Section 182...) SUBSTANCES GENERALLY RECOGNIZED AS SAFE Multiple Purpose GRAS Food Substances § 182.1129 Aluminum potassium sulfate. (a) Product. Aluminum potassium sulfate. (b) Conditions of use. This substance is...

  17. 21 CFR 182.2122 - Aluminum calcium silicate.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Aluminum calcium silicate. 182.2122 Section 182.2122 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED....2122 Aluminum calcium silicate. (a) Product. Aluminum calcium silicate. (b) Tolerance. 2 percent....

  18. 21 CFR 582.1129 - Aluminum potassium sulfate.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 6 2012-04-01 2012-04-01 false Aluminum potassium sulfate. 582.1129 Section 582.1129 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED... Additives § 582.1129 Aluminum potassium sulfate. (a) Product. Aluminum potassium sulfate. (b) Conditions...

  19. 21 CFR 182.1127 - Aluminum ammonium sulfate.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 3 2011-04-01 2011-04-01 false Aluminum ammonium sulfate. 182.1127 Section 182.1127 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED... Food Substances § 182.1127 Aluminum ammonium sulfate. (a) Product. Aluminum ammonium sulfate....

  20. Estimation of primary productivity in Banda Sea using the vertical distribution model

    NASA Astrophysics Data System (ADS)

    Kemili, Putri; Putri, Mutiara R.

    2014-03-01

    To estimate Net Primary Productivity (NPP) which more represent nature condition, it is important to know both horizontal and vertical distribution. Carbon-based Productivity Model (CbPM) used to calculate NPP in 15 layers of depth. Gauss equation and Lambert Beer Law used to estimate chlorophyll-a and light intensity in each layer from satellite-derived data, whereas the temperature data obtained from model result of HAMburg Shelf Ocean Model (HAMSOM). This model is being applied to verified and describe how the NPP had been distributed in Banda Sea on 2006. Verification results show that CbPM algorithm has clearly give less error in data observation than what Vertically Generalized Production Model (VGPM) algorithm did, which stand on the error average approximately 33%. The results also show that the vertical distribution of NPP in Banda Sea indicate a seasonal variation.

  1. The effects of tropospheric ozone on net primary productivity and implications for climate change.

    PubMed

    Ainsworth, Elizabeth A; Yendrek, Craig R; Sitch, Stephen; Collins, William J; Emberson, Lisa D

    2012-01-01

    Tropospheric ozone (O(3)) is a global air pollutant that causes billions of dollars in lost plant productivity annually. It is an important anthropogenic greenhouse gas, and as a secondary air pollutant, it is present at high concentrations in rural areas far from industrial sources. It also reduces plant productivity by entering leaves through the stomata, generating other reactive oxygen species and causing oxidative stress, which in turn decreases photosynthesis, plant growth, and biomass accumulation. The deposition of O(3) into vegetation through stomata is an important sink for tropospheric O(3), but this sink is modified by other aspects of environmental change, including rising atmospheric carbon dioxide concentrations, rising temperature, altered precipitation, and nitrogen availability. We review the atmospheric chemistry governing tropospheric O(3) mass balance, the effects of O(3) on stomatal conductance and net primary productivity, and implications for agriculture, carbon sequestration, and climate change.

  2. Scale-up and economic analysis of biodiesel production from municipal primary sewage sludge.

    PubMed

    Olkiewicz, Magdalena; Torres, Carmen M; Jiménez, Laureano; Font, Josep; Bengoa, Christophe

    2016-08-01

    Municipal wastewater sludge is a promising lipid feedstock for biodiesel production, but the need to eliminate the high water content before lipid extraction is the main limitation for scaling up. This study evaluates the economic feasibility of biodiesel production directly from liquid primary sludge based on experimental data at laboratory scale. Computational tools were used for the modelling of the process scale-up and the different configurations of lipid extraction to optimise this step, as it is the most expensive. The operational variables with a major influence in the cost were the extraction time and the amount of solvent. The optimised extraction process had a break-even price of biodiesel of 1232 $/t, being economically competitive with the current cost of fossil diesel. The proposed biodiesel production process from waste sludge eliminates the expensive step of sludge drying, lowering the biodiesel price. PMID:27131292

  3. Marine foods sourced from farther as their use of global ocean primary production increases.

    PubMed

    Watson, Reg A; Nowara, Gabrielle B; Hartmann, Klaas; Green, Bridget S; Tracey, Sean R; Carter, Chris G

    2015-01-01

    The growing human population must be fed, but historic land-based systems struggle to meet expanding demand. Marine production supports some of the world's poorest people but increasingly provides for the needs of the affluent, either directly by fishing or via fodder-based feeds for marine and terrestrial farming. Here we show the expanding footprint of humans to utilize global ocean productivity to feed themselves. Our results illustrate how incrementally each year, marine foods are sourced farther from where they are consumed and moreover, require an increasing proportion of the ocean's primary productivity that underpins all marine life. Though mariculture supports increased consumption of seafood, it continues to require feeds based on fully exploited wild stocks. Here we examine the ocean's ability to meet our future demands to 2100 and find that even with mariculture supplementing near-static wild catches our growing needs are unlikely to be met without significant changes.

  4. Marine foods sourced from farther as their use of global ocean primary production increases

    PubMed Central

    Watson, Reg A.; Nowara, Gabrielle B.; Hartmann, Klaas; Green, Bridget S.; Tracey, Sean R.; Carter, Chris G.

    2015-01-01

    The growing human population must be fed, but historic land-based systems struggle to meet expanding demand. Marine production supports some of the world's poorest people but increasingly provides for the needs of the affluent, either directly by fishing or via fodder-based feeds for marine and terrestrial farming. Here we show the expanding footprint of humans to utilize global ocean productivity to feed themselves. Our results illustrate how incrementally each year, marine foods are sourced farther from where they are consumed and moreover, require an increasing proportion of the ocean's primary productivity that underpins all marine life. Though mariculture supports increased consumption of seafood, it continues to require feeds based on fully exploited wild stocks. Here we examine the ocean's ability to meet our future demands to 2100 and find that even with mariculture supplementing near-static wild catches our growing needs are unlikely to be met without significant changes. PMID:26079714

  5. The Beverage Can in the United States: Achieving a 100% Recycled Aluminum Can through Supply Chain Innovation

    NASA Astrophysics Data System (ADS)

    Buffington, Jack

    2012-08-01

    The purpose of this research is to analyze why recycled content is low (33-50%) in the aluminum can in the United States when it is technically possible to have a product that is made from 100% recycled material. A comprehensive literature review is conducted, followed by identification of five propositions determined with respect to the research problem. With respect to aluminum can recycling (and its research), there is a greater focus on the role of the consumer than the producer in the aluminum can supply chain system, which may impact on the role of innovation in addressing the problem. The upstream primary aluminum supply chain is vertically integrated and efficient within itself, but not integrated with the downstream secondary aluminum can market. Given the importance of the secondary aluminum market in the United States, there are significant recycling/efficiency/sustainability opportunities to address. As opposed to a dominant focus on consumers and their recycling habits, this study focuses on the aggregate aluminum can supply chain to apply innovation to the solution.

  6. Landscape level influence: aquatic primary production in the Colorado River of Glen and Grand canyons

    NASA Astrophysics Data System (ADS)

    Yard, M. D.; Kennedy, T.; Yackulic, C. B.; Bennett, G. E.

    2012-12-01

    Irregular features common to canyon-bound regions intercept solar incidence (photosynthetic photon flux density [PPFD: μmol m-2 s-1]) and can affect ecosystem energetics. The Colorado River in Grand Canyon is topographically complex, typical of most streams and rivers in the arid southwest. Dam-regulated systems like the Colorado River have reduced sediment loads, and consequently increased water transparency relative to unimpounded rivers; however, sediment supply from tributaries and flow regulation that affects erosion and subsequent sediment transport, interact to create spatial and temporal variation in optical conditions in this river network. Solar incidence and suspended sediment loads regulate the amount of underwater light available for aquatic photosynthesis in this regulated river. Since light availability is depth dependent (Beer's law), benthic algae is often exposed to varying levels of desiccation or reduced light conditions due to daily flow regulation, additional factors that further constrain aquatic primary production. Considerable evidence suggests that the Colorado River food web is now energetically dependent on autotrophic production, an unusual condition since large river foodwebs are typically supported by allochthonous carbon synthesized and transported from terrestrial environments. We developed a mechanistic model to account for these regulating factors to predict how primary production might be affected by observed and alternative flow regimes proposed as part of ongoing adaptive management experimentation. Inputs to our model include empirical data (suspended sediment and temperature), and predictive relationships: 1) solar incidence reaching the water surface (topographic complexity), 2) suspended sediment-light extinction relationships (optical properties), 3) unsteady flow routing model (stage-depth relationship), 4) channel morphology (photosynthetic area), and 5) photosynthetic-irradiant response for dominant algae (Cladophora

  7. Specific features of aluminum nanoparticle water and wet air oxidation

    SciTech Connect

    Lozhkomoev, Aleksandr S. Glazkova, Elena A. Svarovskaya, Natalia V. Bakina, Olga V. Kazantsev, Sergey O. Lerner, Marat I.

    2015-10-27

    The oxidation processes of the electrically exploded aluminum nanopowders in water and in wet air are examined in the paper. The morphology of the intermediate reaction products of aluminum oxidation has been studied using the transmission electron microscopy. It was shown that the aluminum nanopowder water oxidation causes the formation of the hollow spheres with mesoporous boehmite nanosheets coating. The wedge-like bayerite particles are formed during aluminum nanopowder wet air oxidation.

  8. Specific features of aluminum nanoparticle water and wet air oxidation

    NASA Astrophysics Data System (ADS)

    Lozhkomoev, Aleksandr S.; Glazkova, Elena A.; Svarovskaya, Natalia V.; Bakina, Olga V.; Kazantsev, Sergey O.; Lerner, Marat I.

    2015-10-01

    The oxidation processes of the electrically exploded aluminum nanopowders in water and in wet air are examined in the paper. The morphology of the intermediate reaction products of aluminum oxidation has been studied using the transmission electron microscopy. It was shown that the aluminum nanopowder water oxidation causes the formation of the hollow spheres with mesoporous boehmite nanosheets coating. The wedge-like bayerite particles are formed during aluminum nanopowder wet air oxidation.

  9. Monitoring Agricultural Production in Primary Export Countries within the framework of the GEOGLAM Initiative

    NASA Astrophysics Data System (ADS)

    Becker-Reshef, I.; Justice, C. O.; Vermote, E.

    2012-12-01

    Up to date, reliable, global, information on crop production prospects is indispensible for informing and regulating grain markets and for instituting effective agricultural policies. The recent price surges in the global grain markets were in large part triggered by extreme weather events in primary grain export countries. These events raise important questions about the accuracy of current production forecasts and their role in market fluctuations, and highlight the deficiencies in the state of global agricultural monitoring. Satellite-based earth observations are increasingly utilized as a tool for monitoring agricultural production as they offer cost-effective, daily, global information on crop growth and extent and their utility for crop production forecasting has long been demonstrated. Within this context, the Group on Earth Observations developed the Global Agricultural Monitoring (GEOGLAM) initiative which was adopted by the G20 as part of the action plan on food price volatility and agriculture. The goal of GEOGLAM is to enhance agricultural production estimates through the use of Earth observations. This talk will explore the potential contribution of EO-based methods for improving the accuracy of early production estimates of main export countries within the framework of GEOGLAM.

  10. Time Series Analysis Of Primary Productivity Along The East Coast Of India Using Oceansat-2 Ocean Colour Monitor (O cm)

    NASA Astrophysics Data System (ADS)

    Lakshmi, E.; Pratap, D.; Nagamani, P. V.; Rao, K. H.; Preethi Latha, T.; Choudhury, S. B.

    2014-11-01

    Primary Productivity is the ultimate source of energy for all organisms in an ecosystem. It is associated with the food production and the global carbon cycle. Sensors on remote platforms (satellites) are capable of estimating the Chlorophyll-a concentration in surface waters by measurement of spectral changes of the upwelling light. From these data, which connected with other remotely sensed data, it is possible to use algorithms to estimate the primary production. In this paper, an initial attempt is made to estimate the Primary Productivity along the east coast of India. Vertically Generalized Productivity Model (VGPM) which is a depth (euphotic depth) integrated model is used for the estimation. The common input variables or geophysical parameters used for the model are chlorophyll-a concentration (chl-a), vertically diffuse attenuation coefficient (Kd-490), Photosynthetically Available Radiation (PAR), and Sea Surface Temperature (SST). The chlorophyll-a and Kd-490 parameters were estimated using Oceansat-2 OCM data whereas PAR and SST were taken from MODIS-aqua data. Oceansat-2 Ocean Colour Monitor (OCM) data for the year 2013 is used in the analysis to compute the primary productivity using the weekly (8-day) data products of all the parameters as mentioned above. These products were inter compared with the MODIS Weekly (8-day) Primary Productivity products which were estimated at a global scale using the modified Vertically Generalized Productivity Model (VGPM) with which uses the exponential function of Sea surface temperature (SST).

  11. Increased Primary Production from an Exotic Invader Does Not Subsidize Native Rodents.

    PubMed

    Lucero, Jacob E; Allen, Phil S; McMillan, Brock R

    2015-01-01

    Invasive plants have tremendous potential to enrich native food webs by subsidizing net primary productivity. Here, we explored how a potential food subsidy, seeds produced by the aggressive invader cheatgrass (Bromus tectorum), is utilized by an important guild of native consumers--granivorous small mammals--in the Great Basin Desert, USA. In a series of field experiments we examined 1) how cheatgrass invasion affects the density and biomass of seed rain at the ecosystem-level; 2) how seed resources from cheatgrass numerically affect granivorous small mammals; and 3) how the food preferences of native granivores might mediate the trophic integration of cheatgrass seeds. Relative to native productivity, cheatgrass invasion increased the density and biomass of seed rain by over 2000% (P < 0.01) and 3500% (P < 0.01), respectively. However, granivorous small mammals in native communities showed no positive response in abundance, richness, or diversity to experimental additions of cheatgrass seeds over one year. This lack of response correlated with a distinct preference for seeds from native grasses over seeds from cheatgrass. Our experiments demonstrate that increased primary productivity associated with exotic plant invasions may not necessarily subsidize consumers at higher trophic levels. In this context, cheatgrass invasion could disrupt native food webs by providing less-preferred resources that fail to enrich higher trophic levels. PMID:26244345

  12. Quantifying and mapping the human appropriation of net primary production in earth's terrestrial ecosystems

    PubMed Central

    Haberl, Helmut; Erb, K. Heinz; Krausmann, Fridolin; Gaube, Veronika; Bondeau, Alberte; Plutzar, Christoph; Gingrich, Simone; Lucht, Wolfgang; Fischer-Kowalski, Marina

    2007-01-01

    Human appropriation of net primary production (HANPP), the aggregate impact of land use on biomass available each year in ecosystems, is a prominent measure of the human domination of the biosphere. We present a comprehensive assessment of global HANPP based on vegetation modeling, agricultural and forestry statistics, and geographical information systems data on land use, land cover, and soil degradation that localizes human impact on ecosystems. We found an aggregate global HANPP value of 15.6 Pg C/yr or 23.8% of potential net primary productivity, of which 53% was contributed by harvest, 40% by land-use-induced productivity changes, and 7% by human-induced fires. This is a remarkable impact on the biosphere caused by just one species. We present maps quantifying human-induced changes in trophic energy flows in ecosystems that illustrate spatial patterns in the human domination of ecosystems, thus emphasizing land use as a pervasive factor of global importance. Land use transforms earth's terrestrial surface, resulting in changes in biogeochemical cycles and in the ability of ecosystems to deliver services critical to human well being. The results suggest that large-scale schemes to substitute biomass for fossil fuels should be viewed cautiously because massive additional pressures on ecosystems might result from increased biomass harvest. PMID:17616580

  13. Quantifying and mapping the human appropriation of net primary production in earth's terrestrial ecosystems.

    PubMed

    Haberl, Helmut; Erb, K Heinz; Krausmann, Fridolin; Gaube, Veronika; Bondeau, Alberte; Plutzar, Christoph; Gingrich, Simone; Lucht, Wolfgang; Fischer-Kowalski, Marina

    2007-07-31

    Human appropriation of net primary production (HANPP), the aggregate impact of land use on biomass available each year in ecosystems, is a prominent measure of the human domination of the biosphere. We present a comprehensive assessment of global HANPP based on vegetation modeling, agricultural and forestry statistics, and geographical information systems data on land use, land cover, and soil degradation that localizes human impact on ecosystems. We found an aggregate global HANPP value of 15.6 Pg C/yr or 23.8% of potential net primary productivity, of which 53% was contributed by harvest, 40% by land-use-induced productivity changes, and 7% by human-induced fires. This is a remarkable impact on the biosphere caused by just one species. We present maps quantifying human-induced changes in trophic energy flows in ecosystems that illustrate spatial patterns in the human domination of ecosystems, thus emphasizing land use as a pervasive factor of global importance. Land use transforms earth's terrestrial surface, resulting in changes in biogeochemical cycles and in the ability of ecosystems to deliver services critical to human well being. The results suggest that large-scale schemes to substitute biomass for fossil fuels should be viewed cautiously because massive additional pressures on ecosystems might result from increased biomass harvest.

  14. Estimating oceanic primary productivity from ocean color remote sensing: A strategic assessment

    NASA Astrophysics Data System (ADS)

    Lee, Zhongping; Marra, John; Perry, Mary Jane; Kahru, Mati

    2015-09-01

    It has long been realized that approaches using satellite ocean-color remote sensing are the only feasible means to quantify primary productivity (PP) adequately for the global ocean. Through decades of dedicated efforts and with the help of various satellite ocean-color missions, great progresses have been achieved in obtaining global PP as well as its spatial and temporal variations. However, there still exist wide differences between satellite estimations and in situ measurements, as well as large discrepancies among results from different models. The reasons for these large differences are many, which include uncertainties in measurements, errors in satellite-derived products, and limitations in the modeling approaches. Unlike previous round-robin reports on PP modeling where the performance of specific models was evaluated and compared, here we try to provide a candid overview of three primary modeling strategies and the nature of present satellite ocean-color products. We further highlight aspects where efforts should be focused in the coming years, with the overarching goal of reducing the gaps between satellite modeling and in situ measurements.

  15. Increased Primary Production from an Exotic Invader Does Not Subsidize Native Rodents

    PubMed Central

    Lucero, Jacob E.; Allen, Phil S.; McMillan, Brock R.

    2015-01-01

    Invasive plants have tremendous potential to enrich native food webs by subsidizing net primary productivity. Here, we explored how a potential food subsidy, seeds produced by the aggressive invader cheatgrass (Bromus tectorum), is utilized by an important guild of native consumers – granivorous small mammals – in the Great Basin Desert, USA. In a series of field experiments we examined 1) how cheatgrass invasion affects the density and biomass of seed rain at the ecosystem-level; 2) how seed resources from cheatgrass numerically affect granivorous small mammals; and 3) how the food preferences of native granivores might mediate the trophic integration of cheatgrass seeds. Relative to native productivity, cheatgrass invasion increased the density and biomass of seed rain by over 2000% (P < 0.01) and 3500% (P < 0.01), respectively. However, granivorous small mammals in native communities showed no positive response in abundance, richness, or diversity to experimental additions of cheatgrass seeds over one year. This lack of response correlated with a distinct preference for seeds from native grasses over seeds from cheatgrass. Our experiments demonstrate that increased primary productivity associated with exotic plant invasions may not necessarily subsidize consumers at higher trophic levels. In this context, cheatgrass invasion could disrupt native food webs by providing less-preferred resources that fail to enrich higher trophic levels. PMID:26244345

  16. The Revision of Aluminum-containing Food Additive Provisions in China.

    PubMed

    Zhang, Hong; Zhang, Ji Yue; Wang, Hua Li; Luo, Peng Jie; Zhang, Jian Bo

    2016-06-01

    The aim of this study was to revise the provisions for aluminum-containing food additives in GB 2760-2011 (The National Food Safety Standard for Use of Food Additives), in order to reduce aluminum exposure among the Chinese population. According to the latest risk assessment results of JECFA and China on aluminum and the actual use of aluminum-containing food additives in certain products, the aluminum-containing food additive-related provisions in GB 2760-2011 were revised. Those revisions included narrowing down the applicable food categories and adjusting the maximum use level of aluminum potassium sulfate and aluminum ammonium sulfate, repealing nine aluminum-containing food additives in puffed food and repealing the use of sodium aluminum phosphate, sodium aluminosilicate and starch aluminum octenylsuccinate in all food. After revision of the use of aluminum food additive provisions, the weekly dietary intake of aluminum in the Chinese population can be reduced to a safe level. PMID:27470109

  17. Phytoplankton absorption, photosynthetic parameters, and primary production off Baja California: summer and autumn 1998

    NASA Astrophysics Data System (ADS)

    Aguirre-Hernández, Elsa; Gaxiola-Castro, Gilberto; Nájera-Martínez, Sila; Baumgartner, Timothy; Kahru, Mati; Greg Mitchell, B.

    2004-03-01

    To estimate ocean primary production at large space and time scales, it is necessary to use models combined with ocean-color satellite data. Detailed estimates of primary production are typically done at only a few representative stations. To get survey-scale estimates of primary production, one must introduce routinely measured Chlorophyll-a (Chl-a) into models. For best precision, models should be based on accurate parameterizations developed from optical and photosynthesis data collected in the region of interest. To develop regional model parameterizations 14C-bicarbonate was used to estimate in situ primary production and photosynthetic parameters (α* ,Pm* , and Ek) derived from photosynthesis-irradiance (P-E) experiments from IMECOCAL cruises to the southern California Current during July and October 1998. The P-E experiments were done for samples collected from the 50% surface light depth for which we also determined particle and phytoplankton absorption coefficients (ap, aφ, and aφ*). Physical data collected during both surveys indicated that the 1997-1998 El Niño was abating during the summer of 1998, with a subsequent transition to the typical California Current circulation and coastal upwelling conditions. Phytoplankton chl-a and in situ primary production were elevated at coastal stations for both surveys, with the highest values during summer. Phytoplankton specific absorption coefficients in the blue peak (aφ* (440)) ranged from 0.02 to 0.11 m2 (mg Chl-a)-1 with largest values in offshore surface waters. In general aφ* was lower at depth compared to the surface. P-E samples were collected at the 50% light level that was usually in the surface mixed layer. Using α* and spectral absorption, we estimated maximum photosynthetic quantum yields (φmax; mol C/mol quanta). φmax values were lowest in offshore surface waters, with a total range of 0.01-0.07. Mean values of φmax for July and October were 0.011 and 0.022, respectively. In July Pm* was

  18. Net primary productivity of subalpine meadows in Yosemite National Park in relation to climate variability

    USGS Publications Warehouse

    Moore, Peggy E.; Van Wagtendonk, Jan W.; Yee, Julie L.; McClaran, Mitchel P.; Cole, David N.; McDougald, Neil K.; Brooks, Matthew L.

    2013-01-01

    Subalpine meadows are some of the most ecologically important components of mountain landscapes, and primary productivity is important to the maintenance of meadow functions. Understanding how changes in primary productivity are associated with variability in moisture and temperature will become increasingly important with current and anticipated changes in climate. Our objective was to describe patterns and variability in aboveground live vascular plant biomass in relation to climatic factors. We harvested aboveground biomass at peak growth from four 64-m2 plots each in xeric, mesic, and hydric meadows annually from 1994 to 2000. Data from nearby weather stations provided independent variables of spring snow water content, snow-free date, and thawing degree days for a cumulative index of available energy. We assembled these climatic variables into a set of mixed effects analysis of covariance models to evaluate their relationships with annual aboveground net primary productivity (ANPP), and we used an information theoretic approach to compare the quality of fit among candidate models. ANPP in the xeric meadow was negatively related to snow water content and thawing degree days and in the mesic meadow was negatively related to snow water content. Relationships between ANPP and these 2 covariates in the hydric meadow were not significant. Increasing snow water content may limit ANPP in these meadows if anaerobic conditions delay microbial activity and nutrient availability. Increased thawing degree days may limit ANPP in xeric meadows by prematurely depleting soil moisture. Large within-year variation of ANPP in the hydric meadow limited sensitivity to the climatic variables. These relationships suggest that, under projected warmer and drier conditions, ANPP will increase in mesic meadows but remain unchanged in xeric meadows because declines associated with increased temperatures would offset the increases from decreased snow water content.

  19. Cellular Microenvironment Dictates Androgen Production by Murine Fetal Leydig Cells in Primary Culture1

    PubMed Central

    Carney, Colleen M.; Muszynski, Jessica L.; Strotman, Lindsay N.; Lewis, Samantha R.; O'Connell, Rachel L.; Beebe, David J.; Theberge, Ashleigh B.; Jorgensen, Joan S.

    2014-01-01

    ABSTRACT Despite the fact that fetal Leydig cells are recognized as the primary source of androgens in male embryos, the mechanisms by which steroidogenesis occurs within the developing testis remain unclear. A genetic approach was used to visualize and isolate fetal Leydig cells from remaining cells within developing mouse testes. Cyp11a1-Cre mice were bred to mT/mG dual reporter mice to target membrane-tagged enhanced green fluorescent protein (GFP) within steroidogenic cells, whereas other cells expressed membrane-tagged tandem-dimer tomato red. Fetal Leydig cell identity was validated using double-labeled immunohistochemistry against GFP and the steroidogenic enzyme 3beta-HSD, and cells were successfully isolated as indicated by qPCR results from sorted cell populations. Because fetal Leydig cells must collaborate with neighboring cells to synthesize testosterone, we hypothesized that the fetal Leydig cell microenvironment defined their capacity for androgen production. Microfluidic culture devices were used to measure androstenedione and testosterone production of fetal Leydig cells that were cultured in cell-cell contact within a mixed population, were isolated but remained in medium contact via compartmentalized co-culture with other testicular cells, or were isolated and cultured alone. Results showed that fetal Leydig cells maintained their identity and steroidogenic activity for 3–5 days in primary culture. Microenvironment dictated proficiency of testosterone production. As expected, fetal Leydig cells produced androstenedione but not testosterone when cultured in isolation. More testosterone accumulated in medium from mixed cultures than from compartmentalized co-cultures initially; however, co-cultures maintained testosterone synthesis for a longer time. These data suggest that a combination of cell-cell contact and soluble factors constitute the ideal microenvironment for fetal Leydig cell activity in primary culture. PMID:25143354

  20. Cellular microenvironment dictates androgen production by murine fetal Leydig cells in primary culture.

    PubMed

    Carney, Colleen M; Muszynski, Jessica L; Strotman, Lindsay N; Lewis, Samantha R; O'Connell, Rachel L; Beebe, David J; Theberge, Ashleigh B; Jorgensen, Joan S

    2014-10-01

    Despite the fact that fetal Leydig cells are recognized as the primary source of androgens in male embryos, the mechanisms by which steroidogenesis occurs within the developing testis remain unclear. A genetic approach was used to visualize and isolate fetal Leydig cells from remaining cells within developing mouse testes. Cyp11a1-Cre mice were bred to mT/mG dual reporter mice to target membrane-tagged enhanced green fluorescent protein (GFP) within steroidogenic cells, whereas other cells expressed membrane-tagged tandem-dimer tomato red. Fetal Leydig cell identity was validated using double-labeled immunohistochemistry against GFP and the steroidogenic enzyme 3beta-HSD, and cells were successfully isolated as indicated by qPCR results from sorted cell populations. Because fetal Leydig cells must collaborate with neighboring cells to synthesize testosterone, we hypothesized that the fetal Leydig cell microenvironment defined their capacity for androgen production. Microfluidic culture devices were used to measure androstenedione and testosterone production of fetal Leydig cells that were cultured in cell-cell contact within a mixed population, were isolated but remained in medium contact via compartmentalized co-culture with other testicular cells, or were isolated and cultured alone. Results showed that fetal Leydig cells maintained their identity and steroidogenic activity for 3-5 days in primary culture. Microenvironment dictated proficiency of testosterone production. As expected, fetal Leydig cells produced androstenedione but not testosterone when cultured in isolation. More testosterone accumulated in medium from mixed cultures than from compartmentalized co-cultures initially; however, co-cultures maintained testosterone synthesis for a longer time. These data suggest that a combination of cell-cell contact and soluble factors constitute the ideal microenvironment for fetal Leydig cell activity in primary culture. PMID:25143354

  1. Estimating crop net primary production using inventory data and MODIS-derived parameters

    SciTech Connect

    Bandaru, Varaprasad; West, Tristram O.; Ricciuto, Daniel M.; Izaurralde, Roberto C.

    2013-06-03

    National estimates of spatially-resolved cropland net primary production (NPP) are needed for diagnostic and prognostic modeling of carbon sources, sinks, and net carbon flux. Cropland NPP estimates that correspond with existing cropland cover maps are needed to drive biogeochemical models at the local scale and over national and continental extents. Existing satellite-based NPP products tend to underestimate NPP on croplands. A new Agricultural Inventory-based Light Use Efficiency (AgI-LUE) framework was developed to estimate individual crop biophysical parameters for use in estimating crop-specific NPP. The method is documented here and evaluated for corn and soybean crops in Iowa and Illinois in years 2006 and 2007. The method includes a crop-specific enhanced vegetation index (EVI) from the Moderate Resolution Imaging Spectroradiometer (MODIS), shortwave radiation data estimated using Mountain Climate Simulator (MTCLIM) algorithm and crop-specific LUE per county. The combined aforementioned variables were used to generate spatially-resolved, crop-specific NPP that correspond to the Cropland Data Layer (CDL) land cover product. The modeling framework represented well the gradient of NPP across Iowa and Illinois, and also well represented the difference in NPP between years 2006 and 2007. Average corn and soybean NPP from AgI-LUE was 980 g C m-2 yr-1 and 420 g C m-2 yr-1, respectively. This was 2.4 and 1.1 times higher, respectively, for corn and soybean compared to the MOD17A3 NPP product. Estimated gross primary productivity (GPP) derived from AgI-LUE were in close agreement with eddy flux tower estimates. The combination of new inputs and improved datasets enabled the development of spatially explicit and reliable NPP estimates for individual crops over large regional extents.

  2. Aluminum-air battery crystallizer

    SciTech Connect

    Maimoni, A.

    1987-01-23

    A prototype crystallizer system for the aluminum-air battery operated reliably through simulated startup and shutdown cycles and met its design objectives. The crystallizer system allows for crystallization and removal of the aluminium hydroxide reaction product; it is required to allow steady-state and long-term operation of the aluminum-air battery. The system has to minimize volume and maintain low turbulence and shear to minimize secondary nucleation and energy consumption while enhancing agglomeration. A lamella crystallizer satisfies system constraints.

  3. Low Cost Cast Aluminum Metal Matrix Composites Have Arrived

    SciTech Connect

    Herling, Darrell R.; Hunt, Warren

    2004-03-01

    Aluminum metal matrix composites (MMC) have found applications in many industries, from aerospace and automotive to sporting goods and electronics packaging [1-5]. Many of the primary applications have been in military components and structures, where advanced high performance materials are necessary to meet vigorous material challenges. Aluminum MMC are attractive due to their lightweight and high specific stiffness. In addition, the ceramic particle reinforcement significantly increases the wear resistance of these materials. Nevertheless, high materials costs relative to conventional aluminum alloys have been the primary limit to widespread use of such a material family. The use of particulate instead of fiber reinforcement has helped to reduce the overall material cost for those applications that do not require the additional strength obtained from fiber reinforced composites. However, for many cost sensitive industries, such as the on-highway transportation industry, widespread application of particulate reinforced MMC is still limited due to cost and availability. There are two primary components that makeup the cost of metal matrix composite feedstock material. The first is the raw material cost, which is somewhat controlled by the cost of aluminum. However, the raw material used for the reinforcement can play a significant role in the overall MMC material cost. This incurred cost can be affected through the use of alternative and less costly ceramic material options. The other source of cost is related to the compositing processes used to make the aluminum MMC materials. If the cost associated with these two aspects can be controlled and reduced, then this could enable widespread use of particle reinforced aluminum MMC materials. Metal Matrix Composites for the 21st Century (MC-21), Inc., in Carson City, Nevada, has developed a novel rapid mixing process for the production of MMC materials. This is a proprietary process, with the focus of rapidly mixing the

  4. Worldwide estimates and bibliography of net primary productivity derived from pre-1982 publications

    SciTech Connect

    Esser, G.; Lieth, H.F.H.; Scurlock, J.M.O.; Olson, R.J.

    1997-10-01

    An extensive compilation of more than 700 field estimates of net primary productivity of natural and agricultural ecosystems worldwide was synthesized in Germany in the 1970s and early 1980s. Although the Osnabrueck data set has not been updated since the 1980s, it represents a wealth of information for use in model development and validation. This report documents the development of this data set, its contents, and its recent availability on the Internet from the Oak Ridge National Laboratory Distributed Active Archive Center for Biogeochemical Dynamics. Caution is advised in using these data, which necessarily include assumptions and conversions that may not be universally applicable to all sites.

  5. Comparing global models of terrestrial net primary productivity (NPP): Global pattern and differentiation by major biomes

    USGS Publications Warehouse

    Kicklighter, D.W.; Bondeau, A.; Schloss, A.L.; Kaduk, J.; McGuire, A.D.

    1999-01-01

    Annual and seasonal net primary productivity estimates (NPP) of 15 global models across latitudinal zones and biomes are compared. The models simulated NPP for contemporary climate using common, spatially explicit data sets for climate, soil texture, and normalized difference vegetation index (NDVI). Differences among NPP estimates varied over space and time. The largest differences occur during the summer months in boreal forests (50??to 60??N) and during the dry seasons of tropical evergreen forests. Differences in NPP estimates are related to model assumptions about vegetation structure, model parameterizations, and input data sets.

  6. Toward Describing the Effects of Ozone Depletion on Marine Primary Productivity and Carbon Cycling

    NASA Technical Reports Server (NTRS)

    Cullen, John J.

    1995-01-01

    This project was aimed at improved predictions of the effects of UVB and ozone depletion on marine primary productivity and carbon flux. A principal objective was to incorporate a new analytical description of photosynthesis as a function of UV and photosynthetically available radiation (Cullen et. al., Science 258:646) into a general oceanographic model. We made significant progress: new insights into the kinetics of photoinhibition were used in the analysis of experiments on Antarctic phytoplankton to generate a general model of UV-induced photoinhibition under the influence of ozone depletion and vertical mixing. The way has been paved for general models on a global scale.

  7. Nutrient dynamics and primary production in a pristine coastal mangrove ecosystem: Andaman Islands, India

    NASA Astrophysics Data System (ADS)

    Jenkins, E. N.; Nickodem, K.; Siemann, A. L.; Hoeher, A.; Sundareshwar, P. V.; Ramesh, R.; Purvaja, R.; Banerjee, K.; Manickam, S.; Haran, H.

    2012-12-01

    Mangrove ecosystems play a key role in supporting coastal food webs and nutrient cycles in the coastal zone. Their strategic position between the land and the sea make them important sites for land-ocean interaction. As part of an Indo-US summer field course we investigated changes in the water chemistry in a pristine mangrove creek located at Wright Myo in the Andaman Islands, India. This study was conducted during the wet season (June 2012) to evaluate the influence of the coastal mangrove wetlands on the water quality and productivity in adjoining pelagic waters. Over a full tidal cycle spanning approximately 24 hrs, we measured nutrient concentrations and other ancillary parameters (e.g. dissolved oxygen, turbidity, salinity, etc.) hourly to evaluate water quality changes in incoming and ebbing tides. Nutrient analyses had the following concentration ranges (μM): nitrite 0.2-0.9, nitrate 2.0-11.5, ammonium 1.3-7.5, dissolved inorganic phosphate 0.7-2.8. The dissolved inorganic nitrogen to dissolved inorganic phosphate (DIN/DIP) ratio was very low relative to an optimal ratio, suggesting growth is nitrogen limited. In addition, we conducted primary production assays to investigate the factors that controlled primary production in this pristine creek. The experiment was carried out in situ using the Winkler method at low and high tide. Four-hour incubation of light and dark bottles representing a fixed control, non-fertilized, fertilized with nitrate, and fertilized with phosphate enabled the measurement of both net oxygen production and dark respiration. The low tide experiment suggests the ecosystem is heterotrophic because the oxygen measured in the light bottles was consistently less than that of the dark bottles. This result may be an experimental artifact of placing the glass bottles in the sun for too long prior to incubation, potentially leading to photolysis of large organic molecules in the light bottles. The high tide experiment also displayed

  8. Hydrologic remediation for the Deepwater Horizon incident drove ancillary primary production increase in coastal swamps

    USGS Publications Warehouse

    Middleton, Beth A.; Johnson, Darren; Roberts, Brian J

    2015-01-01

    As coastal wetlands subside worldwide, there is an urgency to understand the hydrologic drivers and dynamics of plant production and peat accretion. One incidental test of the effects of high rates of discharge on forested wetland production occurred in response to the 2010 Deepwater Horizon incident, in which all diversions in Louisiana were operated at or near their maximum discharge level for an extended period to keep offshore oil from threatened coastal wetlands. Davis Pond Diversion was operated at six times the normal discharge levels for almost 4 months, so that Taxodium distichum swamps downstream of the diversion experienced greater inundation and lower salinity. After this remediation event in 2010, above-ground litter production increased by 2.7 times of production levels in 2007–2011. Biomass of the leaf and reproductive tissues of several species increased; wood litter was minimal and did not change during this period. Root production decreased in 2010 but subsequently returned to pre-remediation values in 2011. Both litter and root production remained high in the second growing season after hydrologic remediation. Annual tree growth (circumference increment) was not significantly altered by the remediation. The potential of freshwater pulses for regulating tidal swamp production is further supported by observations of higher T. distichum growth in lower salinity and/or pulsed environments across the U.S. Gulf Coast. Usage of freshwater pulses to manage altered estuaries deserves further consideration, particularly because the timing and duration of such pulses could influence both primary production and peat accretion.

  9. Uncertainty analysis of terrestrial net primary productivity and net biome productivity in China during 1901-2005

    NASA Astrophysics Data System (ADS)

    Shao, Junjiong; Zhou, Xuhui; Luo, Yiqi; Zhang, Guodong; Yan, Wei; Li, Jiaxuan; Li, Bo; Dan, Li; Fisher, Joshua B.; Gao, Zhiqiang; He, Yong; Huntzinger, Deborah; Jain, Atul K.; Mao, Jiafu; Meng, Jihua; Michalak, Anna M.; Parazoo, Nicholas C.; Peng, Changhui; Poulter, Benjamin; Schwalm, Christopher R.; Shi, Xiaoying; Sun, Rui; Tao, Fulu; Tian, Hanqin; Wei, Yaxing; Zeng, Ning; Zhu, Qiuan; Zhu, Wenquan

    2016-05-01

    Despite the importance of net primary productivity (NPP) and net biome productivity (NBP), estimates of NPP and NBP for China are highly uncertain. To investigate the main sources of uncertainty, we synthesized model estimates of NPP and NBP for China from published literature and the Multi-scale Synthesis and Terrestrial Model Intercomparison Project (MsTMIP). The literature-based results showed that total NPP and NBP in China were 3.35 ± 1.25 and 0.14 ± 0.094 Pg C yr-1, respectively. Classification and regression tree analysis based on literature data showed that model type was the primary source of the uncertainty, explaining 36% and 64% of the variance in NPP and NBP, respectively. Spatiotemporal scales, land cover conditions, inclusion of the N cycle, and effects of N addition also contributed to the overall uncertainty. Results based on the MsTMIP data suggested that model structures were overwhelmingly important (>90%) for the overall uncertainty compared to simulations with different combinations of time-varying global change factors. The interannual pattern of NPP was similar among diverse studies and increased by 0.012 Pg C yr-1 during 1981-2000. In addition, high uncertainty in China's NPP occurred in areas with high productivity, whereas NBP showed the opposite pattern. Our results suggest that to significantly reduce uncertainty in estimated NPP and NBP, model structures should be substantially tested on the basis of empirical results. To this end, coordinated distributed experiments with multiple global change factors might be a practical approach that can validate specific structures of different models.

  10. The influence of mixing on primary productivity: A unique application of classical critical depth theory

    NASA Astrophysics Data System (ADS)

    van Ruth, Paul D.; Ganf, George G.; Ward, Tim M.

    2010-06-01

    Mixing and primary productivity was examined in upwelling influenced nearshore waters off south western Eyre Peninsula (SWEP) in the eastern Great Australian Bight (EGAB), the economically and ecologically important shelf region off southern Australia that forms part of the Southern and Indian oceans. Mixing/stratification in the region was highly temporally variable with a unique upwelling circulation in summer/autumn (November-April), and downwelling through winter/spring (May-September). Highest productivity was associated with upwelled/stratified water (up to 2958 mg C m -2 d -1), with low productivity during periods of downwelling and mixing (∼300-550 mg C m -2 d -1), yet no major variations in macro-nutrient concentrations were detected between upwelling and downwelling events (silica > 1 μmol L -1, nitrate/nitrite > 0.4 μmol L -1, phosphate > 0.1 μmol L -1). We hypothesise that upwelling enriches the region with micro-nutrients. High productivity off SWEP appears to be driven by a shallowing of mixed layer depth due to the injection of upwelled waters above Zcr. Low productivity follows the suppression of enrichment during downwelling/mixing events, and is exacerbated in winter/spring by low irradiances and short daylengths.

  11. Quantifying subtropical North Pacific gyre mixed layer primary productivity from Seaglider observations of diel oxygen cycles

    NASA Astrophysics Data System (ADS)

    Nicholson, David P.; Wilson, Samuel T.; Doney, Scott C.; Karl, David M.

    2015-05-01

    Using autonomous underwater gliders, we quantified diurnal periodicity in dissolved oxygen, chlorophyll, and temperature in the subtropical North Pacific near the Hawaii Ocean Time-series (HOT) Station ALOHA during summer 2012. Oxygen optodes provided sufficient stability and precision to quantify diel cycles of average amplitude of 0.6 µmol kg-1. A theoretical diel curve was fit to daily observations to infer an average mixed layer gross primary productivity (GPP) of 1.8 mmol O2 m-3 d-1. Cumulative net community production (NCP) over 110 days was 500 mmol O2 m-2 for the mixed layer, which averaged 57 m in depth. Both GPP and NCP estimates indicated a significant period of below-average productivity at Station ALOHA in 2012, an observation confirmed by 14C productivity incubations and O2/Ar ratios. Given our success in an oligotrophic gyre where biological signals are small, our diel GPP approach holds promise for remote characterization of productivity across the spectrum of marine environments.

  12. Net primary production of a temperate deciduous forest exhibits a threshold response to increasing disturbance severity.

    PubMed

    Stuart-Haëntjens, Ellen J; Curtis, Peter S; Fahey, Robert T; Vogel, Christoph S; Gough, Christopher M

    2015-09-01

    The global carbon (C) balance is vulnerable to disturbances that alter terrestrial C storage. Disturbances to forests occur along a continuum of severity, from low-intensity disturbance causing the mortality or defoliation of only a subset of trees to severe stand- replacing disturbance that kills all trees; yet considerable uncertainty remains in how forest production changes across gradients of disturbance intensity. We used a gradient of tree mortality in an upper Great Lakes forest ecosystem to: (1) quantify how aboveground wood net primary production (ANPP,) responds to a range of disturbance severities; and (2) identify mechanisms supporting ANPPw resistance or resilience following moderate disturbance. We found that ANPPw declined nonlinearly with rising disturbance severity, remaining stable until >60% of the total tree basal area senesced. As upper canopy openness increased from disturbance, greater light availability to the subcanopy enhanced the leaf-level photosynthesis and growth of this formerly light-limited canopy stratum, compensating for upper canopy production losses and a reduction in total leaf area index (LAI). As a result, whole-ecosystem production efficiency (ANPPw/LAI) increased with rising disturbance severity, except in plots beyond the disturbance threshold. These findings provide a mechanistic explanation for a nonlinear relationship between ANPPw, and disturbance severity, in which the physiological and growth enhancement of undisturbed vegetation is proportional to the level of disturbance until a threshold is exceeded. Our results have important ecological and management implications, demonstrating that in some ecosystems moderate levels of disturbance minimally alter forest production. PMID:26594704

  13. Net primary production of a temperate deciduous forest exhibits a threshold response to increasing disturbance severity.

    PubMed

    Stuart-Haëntjens, Ellen J; Curtis, Peter S; Fahey, Robert T; Vogel, Christoph S; Gough, Christopher M

    2015-09-01

    The global carbon (C) balance is vulnerable to disturbances that alter terrestrial C storage. Disturbances to forests occur along a continuum of severity, from low-intensity disturbance causing the mortality or defoliation of only a subset of trees to severe stand- replacing disturbance that kills all trees; yet considerable uncertainty remains in how forest production changes across gradients of disturbance intensity. We used a gradient of tree mortality in an upper Great Lakes forest ecosystem to: (1) quantify how aboveground wood net primary production (ANPP,) responds to a range of disturbance severities; and (2) identify mechanisms supporting ANPPw resistance or resilience following moderate disturbance. We found that ANPPw declined nonlinearly with rising disturbance severity, remaining stable until >60% of the total tree basal area senesced. As upper canopy openness increased from disturbance, greater light availability to the subcanopy enhanced the leaf-level photosynthesis and growth of this formerly light-limited canopy stratum, compensating for upper canopy production losses and a reduction in total leaf area index (LAI). As a result, whole-ecosystem production efficiency (ANPPw/LAI) increased with rising disturbance severity, except in plots beyond the disturbance threshold. These findings provide a mechanistic explanation for a nonlinear relationship between ANPPw, and disturbance severity, in which the physiological and growth enhancement of undisturbed vegetation is proportional to the level of disturbance until a threshold is exceeded. Our results have important ecological and management implications, demonstrating that in some ecosystems moderate levels of disturbance minimally alter forest production.

  14. Cleaning products and air fresheners: exposure to primary and secondary air pollutants

    NASA Astrophysics Data System (ADS)

    Nazaroff, William W.; Weschler, Charles J.

    Building occupants, including cleaning personnel, are exposed to a wide variety of airborne chemicals when cleaning agents and air fresheners are used in buildings. Certain of these chemicals are listed by the state of California as toxic air contaminants (TACs) and a subset of these are regulated by the US federal government as hazardous air pollutants (HAPs). California's Proposition 65 list of species recognized as carcinogens or reproductive toxicants also includes constituents of certain cleaning products and air fresheners. In addition, many cleaning agents and air fresheners contain chemicals that can react with other air contaminants to yield potentially harmful secondary products. For example, terpenes can react rapidly with ozone in indoor air generating many secondary pollutants, including TACs such as formaldehyde. Furthermore, ozone-terpene reactions produce the hydroxyl radical, which reacts rapidly with organics, leading to the formation of other potentially toxic air pollutants. Indoor reactive chemistry involving the nitrate radical and cleaning-product constituents is also of concern, since it produces organic nitrates as well as some of the same oxidation products generated by ozone and hydroxyl radicals. Few studies have directly addressed the indoor concentrations of TACs that might result from primary emissions or secondary pollutant formation following the use of cleaning agents and air fresheners. In this paper, we combine direct empirical evidence with the basic principles of indoor pollutant behavior and with information from relevant studies, to analyze and critically assess air pollutant exposures resulting from the use of cleaning products and air fresheners. Attention is focused on compounds that are listed as HAPs, TACs or Proposition 65 carcinogens/reproductive toxicants and compounds that can readily react to generate secondary pollutants. The toxicity of many of these secondary pollutants has yet to be evaluated. The inhalation

  15. Surface coagulation, microbial respiration and primary production in the Sargasso Sea

    NASA Astrophysics Data System (ADS)

    Kepkay, P. E.; Harrison, W. G.; Irwin, B.

    1990-01-01

    Coagulation of colloidal organic material onto bubble surfaces caused a rapid and short-lived increase of microbial respiration in Sargasso surface water. This process of surface coagulation in a nutrient-poor, stratified water column enhanced respiration in the mixed layer by a factor of 8.6-11.2. Net bacterial biomass also was increased by a factor of 2.0-6.7. This was in contrast to results from previous work in coastal waters where, in response to bubbling, the net increase of bacterial biomass was minimal. Enhancement of respiration was correlated positively with primary production, negatively with chlorophyll and decreased rapidly towards the base of the mixed layer. This suggests that surface coagulation had little impact on "older" DOC in deeper water. Instead, bubbling appeared to be confined in its biological effect to "newer" colloids associated with higher productivity near the ocean surface.

  16. The Whale Pump: Marine Mammals Enhance Primary Productivity in a Coastal Basin

    PubMed Central

    Roman, Joe; McCarthy, James J.

    2010-01-01

    It is well known that microbes, zooplankton, and fish are important sources of recycled nitrogen in coastal waters, yet marine mammals have largely been ignored or dismissed in this cycle. Using field measurements and population data, we find that marine mammals can enhance primary productivity in their feeding areas by concentrating nitrogen near the surface through the release of flocculent fecal plumes. Whales and seals may be responsible for replenishing 2.3×104 metric tons of N per year in the Gulf of Maine's euphotic zone, more than the input of all rivers combined. This upward “whale pump” played a much larger role before commercial harvest, when marine mammal recycling of nitrogen was likely more than three times atmospheric N input. Even with reduced populations, marine mammals provide an important ecosystem service by sustaining productivity in regions where they occur in high densities. PMID:20949007

  17. A conceptual model of primary productivity in shallow streams using biomass simulation. Technical completion report

    SciTech Connect

    Elliott, J.C.; McDonnell, A.J.

    1982-06-01

    A conceptual model for primary productivity was developed for application to rooted aquatic macrophytes in streams to assist studies of eutrophication and control of water quality in supplementing outputs of dissolved oxygen (DO) models of pollution loads. This model included a first-order differential equation of biomass, with specific rates for photosynthesis, respiration, and death. A model component was developed to describe available light spatially/temporally in the weed bed, as reduced from extraterrestrial solar radiation. A DO model component included terms for photosynthetic production, plant respiration, and a benthal sink due to dead plant matter decay. The latter, a first-order exponential oxygen sink, had not been previously included in DO models.

  18. Size-fractionated dissolved primary production and carbohydrate composition of the coccolithophore Emiliania huxleyi

    NASA Astrophysics Data System (ADS)

    Borchard, C.; Engel, A.

    2015-02-01

    Extracellular release (ER) by phytoplankton is the major source of fresh dissolved organic carbon (DOC) in marine ecosystems and accompanies primary production during all growth phases. Little is known, so far, on size and composition of released molecules, and to which extent ER occurs passively, by leakage, or actively, by exudation. Here, we report on ER by the widespread and bloom-forming coccolithophore Emiliania huxleyi grown under steady-state conditions in phosphorus-controlled chemostats (N:P = 29, growth rate of μ = 0.2 d-1) at present-day and high-CO2 concentrations. 14C incubations were performed to determine primary production (PP), comprised of particulate (PO14C) and dissolved organic carbon (DO14C). Concentration and composition of particulate combined carbohydrates (pCCHO) and high-molecular-weight (>1 kDa, HMW) dissolved combined carbohydrates (dCCHO) were determined by ion chromatography. Information on size distribution of ER products was obtained by investigating distinct size classes (<0.4 μm (DO14C), <0.45 μm (HMW-dCCHO), <1000, <100 and <10 kDa) of DO14CC and HMW-dCCHO. Our results revealed relatively low ER during steady-state growth, corresponding to ~4.5% of primary production, and similar ER rates for all size classes. Acidic sugars had a significant share on freshly produced pCCHO as well as on HMW-dCCHO. While pCCHO and the smallest size fraction (<10 kDa) of HMW-dCCHO exhibited a similar sugar composition, dominated by high percentage of glucose (74-80 mol%), the composition of HMW-dCCHO size classes >10 kDa was significantly different, with a higher mol% of arabinose. The mol% of acidic sugars increased and that of glucose decreased with increasing size of HMW-dCCHO. We conclude that larger polysaccharides follow different production and release pathways than smaller molecules, potentially serving distinct ecological and biogeochemical functions.

  19. High Primary Production Contrasts with Intense Carbon Emission in a Eutrophic Tropical Reservoir.

    PubMed

    Almeida, Rafael M; Nóbrega, Gabriel N; Junger, Pedro C; Figueiredo, Aline V; Andrade, Anízio S; de Moura, Caroline G B; Tonetta, Denise; Oliveira, Ernandes S; Araújo, Fabiana; Rust, Felipe; Piñeiro-Guerra, Juan M; Mendonça, Jurandir R; Medeiros, Leonardo R; Pinheiro, Lorena; Miranda, Marcela; Costa, Mariana R A; Melo, Michaela L; Nobre, Regina L G; Benevides, Thiago; Roland, Fábio; de Klein, Jeroen; Barros, Nathan O; Mendonça, Raquel; Becker, Vanessa; Huszar, Vera L M; Kosten, Sarian

    2016-01-01

    Recent studies from temperate lakes indicate that eutrophic systems tend to emit less carbon dioxide (CO2) and bury more organic carbon (OC) than oligotrophic ones, rendering them CO2 sinks in some cases. However, the scarcity of data from tropical systems is critical for a complete understanding of the interplay between eutrophication and aquatic carbon (C) fluxes in warm waters. We test the hypothesis that a warm eutrophic system is a source of both CO2 and CH4 to the atmosphere, and that atmospheric emissions are larger than the burial of OC in sediments. This hypothesis was based on the following assumptions: (i) OC mineralization rates are high in warm water systems, so that water column CO2 production overrides the high C uptake by primary producers, and (ii) increasing trophic status creates favorable conditions for CH4 production. We measured water-air and sediment-water CO2 fluxes, CH4 diffusion, ebullition and oxidation, net ecosystem production (NEP) and sediment OC burial during the dry season in a eutrophic reservoir in the semiarid northeastern Brazil. The reservoir was stratified during daytime and mixed during nighttime. In spite of the high rates of primary production (4858 ± 934 mg C m(-2) d(-1)), net heterotrophy was prevalent due to high ecosystem respiration (5209 ± 992 mg C m(-2) d(-1)). Consequently, the reservoir was a source of atmospheric CO2 (518 ± 182 mg C m(-2) d(-1)). In addition, the reservoir was a source of ebullitive (17 ± 10 mg C m(-2) d(-1)) and diffusive CH4 (11 ± 6 mg C m(-2) d(-1)). OC sedimentation was high (1162 mg C m(-2) d(-1)), but our results suggest that the majority of it is mineralized to CO2 (722 ± 182 mg C m(-2) d(-1)) rather than buried as OC (440 mg C m(-2) d(-1)). Although temporally resolved data would render our findings more conclusive, our results suggest that despite being a primary production and OC burial hotspot, the tropical eutrophic system studied here was a stronger CO2 and CH4 source than a C

  20. High Primary Production Contrasts with Intense Carbon Emission in a Eutrophic Tropical Reservoir

    PubMed Central

    Almeida, Rafael M.; Nóbrega, Gabriel N.; Junger, Pedro C.; Figueiredo, Aline V.; Andrade, Anízio S.; de Moura, Caroline G. B.; Tonetta, Denise; Oliveira, Ernandes S.; Araújo, Fabiana; Rust, Felipe; Piñeiro-Guerra, Juan M.; Mendonça, Jurandir R.; Medeiros, Leonardo R.; Pinheiro, Lorena; Miranda, Marcela; Costa, Mariana R. A.; Melo, Michaela L.; Nobre, Regina L. G.; Benevides, Thiago; Roland, Fábio; de Klein, Jeroen; Barros, Nathan O.; Mendonça, Raquel; Becker, Vanessa; Huszar, Vera L. M.; Kosten, Sarian

    2016-01-01

    Recent studies from temperate lakes indicate that eutrophic systems tend to emit less carbon dioxide (CO2) and bury more organic carbon (OC) than oligotrophic ones, rendering them CO2 sinks in some cases. However, the scarcity of data from tropical systems is critical for a complete understanding of the interplay between eutrophication and aquatic carbon (C) fluxes in warm waters. We test the hypothesis that a warm eutrophic system is a source of both CO2 and CH4 to the atmosphere, and that atmospheric emissions are larger than the burial of OC in sediments. This hypothesis was based on the following assumptions: (i) OC mineralization rates are high in warm water systems, so that water column CO2 production overrides the high C uptake by primary producers, and (ii) increasing trophic status creates favorable conditions for CH4 production. We measured water-air and sediment-water CO2 fluxes, CH4 diffusion, ebullition and oxidation, net ecosystem production (NEP) and sediment OC burial during the dry season in a eutrophic reservoir in the semiarid northeastern Brazil. The reservoir was stratified during daytime and mixed during nighttime. In spite of the high rates of primary production (4858 ± 934 mg C m-2 d-1), net heterotrophy was prevalent due to high ecosystem respiration (5209 ± 992 mg C m-2 d-1). Consequently, the reservoir was a source of atmospheric CO2 (518 ± 182 mg C m-2 d-1). In addition, the reservoir was a source of ebullitive (17 ± 10 mg C m-2 d-1) and diffusive CH4 (11 ± 6 mg C m-2 d-1). OC sedimentation was high (1162 mg C m-2 d-1), but our results suggest that the majority of it is mineralized to CO2 (722 ± 182 mg C m-2 d-1) rather than buried as OC (440 mg C m-2 d-1). Although temporally resolved data would render our findings more conclusive, our results suggest that despite being a primary production and OC burial hotspot, the tropical eutrophic system studied here was a stronger CO2 and CH4 source than a C sink, mainly because of high