Science.gov

Sample records for phosphorus 33

  1. Parameterization of DFTB3/3OB for Sulfur and Phosphorus for Chemical and Biological Applications

    PubMed Central

    2015-01-01

    We report the parametrization of the approximate density functional tight binding method, DFTB3, for sulfur and phosphorus. The parametrization is done in a framework consistent with our previous 3OB set established for O, N, C, and H, thus the resulting parameters can be used to describe a broad set of organic and biologically relevant molecules. The 3d orbitals are included in the parametrization, and the electronic parameters are chosen to minimize errors in the atomization energies. The parameters are tested using a fairly diverse set of molecules of biological relevance, focusing on the geometries, reaction energies, proton affinities, and hydrogen bonding interactions of these molecules; vibrational frequencies are also examined, although less systematically. The results of DFTB3/3OB are compared to those from DFT (B3LYP and PBE), ab initio (MP2, G3B3), and several popular semiempirical methods (PM6 and PDDG), as well as predictions of DFTB3 with the older parametrization (the MIO set). In general, DFTB3/3OB is a major improvement over the previous parametrization (DFTB3/MIO), and for the majority cases tested here, it also outperforms PM6 and PDDG, especially for structural properties, vibrational frequencies, hydrogen bonding interactions, and proton affinities. For reaction energies, DFTB3/3OB exhibits major improvement over DFTB3/MIO, due mainly to significant reduction of errors in atomization energies; compared to PM6 and PDDG, DFTB3/3OB also generally performs better, although the magnitude of improvement is more modest. Compared to high-level calculations, DFTB3/3OB is most successful at predicting geometries; larger errors are found in the energies, although the results can be greatly improved by computing single point energies at a high level with DFTB3 geometries. There are several remaining issues with the DFTB3/3OB approach, most notably its difficulty in describing phosphate hydrolysis reactions involving a change in the coordination number of the phosphorus, for which a specific parametrization (3OB/OPhyd) is developed as a temporary solution; this suggests that the current DFTB3 methodology has limited transferability for complex phosphorus chemistry at the level of accuracy required for detailed mechanistic investigations. Therefore, fundamental improvements in the DFTB3 methodology are needed for a reliable method that describes phosphorus chemistry without ad hoc parameters. Nevertheless, DFTB3/3OB is expected to be a competitive QM method in QM/MM calculations for studying phosphorus/sulfur chemistry in condensed phase systems, especially as a low-level method that drives the sampling in a dual-level QM/MM framework. PMID:24803865

  2. Three-step preparation and purification of phosphorus-33-labeled creatine phosphate of high specific activity

    SciTech Connect

    Savabi, F.; Geiger, P.J.; Bessman, S.P.

    1984-03-01

    Rabbit heart mitochondria were used as a source of enzymes for the synthesis of phosphorus-labeled creatine phosphate. This method is based on the coupled reaction between mitochondrial oxidative phosphorylation and mitochondrial-bound creatine kinase. It is possible to convert more than 90% of the inorganic phosphate (P/sub i/) to creatine phosphate. The method used only small amounts of adenine nucleotides which led to a product with only slight nucleotide contamination. This could be removed by activated charcoal extraction. For further purification, a method for the removal of residual P/sub i/ is described. 20 references.

  3. Competition between roots and microorganisms for phosphorus: A novel 33P labeling approach

    NASA Astrophysics Data System (ADS)

    Zilla, Thomas; Kuzyakov, Yakov; Zavišiæ, Aljoša; Polle, Andrea

    2015-04-01

    While organic N mineralization exhibits clear seasonal uptake dynamics, knowledge about seasonal variation in microbial P uptake and mineralization is scarce. We hypothesize that the dynamics of P uptake and mineralization by microorganisms in temperate forest soils exhibit a seasonality anti-cyclic to plant P uptake. Therefore, the ratio of microbial P to labile P increases by the transition from acquiring ecosystems (in spring) to recycling ones (in fall). To investigate this, intact soil-plant mesocosms containing Ah horizon with 1 year old F. sylvatica were removed from the P-rich field site Bad Brueckenau and the P-depleted field site Luess in Germany. During incubation under controlled conditions, seasonal pulse labeling by 33P-orthophosphate was performed at 5 time points over the course of one year. 33P recovery in microbial compounds of organic and mineral soil horizons was determined 7 and 30 days after the labeling. This procedure will account for temporal changes in P allocation and also considers the rather slow P transport from the mycorrhiza into the plants and other microorganisms. For the first time we analyzed the 33P incorporation into total PLFA and consequently provide a new technique for the analysis of P uptake by microorganisms, which has clear advantages compared to P quantification after chloroform fumigation. Polar lipids are hereby extracted with a Frostegård-modified Bligh-and-Dyer buffer, i.e. a single phase mixture of chloroform, methanol and citrate buffer (0.8:1:2, v:v:v). Phospholipids (PLFA) are isolated and purified by solid phase extraction via a silica gel column chromatography. Subsequently, PLFA are hydrolyzed and the resulting fatty acids derivatized by methylation. The fatty acid methyl esters were extracted with n-hexane and measured by GC/MS to investigate the composition of the microbial community. The remaining extract, containing head groups, phosphate units and glycerol backbones, was used to determine 33P activity and recovery in the microbial membrane lipids with a multi-purpose scintillation counter. This approach offers the unique possibility to quantify P fluxes through the microbial network. For the first time, P cycling can be linked to changes in microbial community structure and activity in soils in situ.

  4. Novel Gold(I) and Silver(I) Complexes of Phosphorus-1,1,-dithiolates and Molecular Structure of [O,O’-(Bornyl)2PS2]H3NC(CH3)3

    PubMed Central

    2013-01-01

    Background The novel chiral phosphorus-1,1-dithiolates [4-CH3OC6H4P(S)(OR)S]-[H3NC(CH3)3]+ were synthesized by the reaction of [RPS2)]2 (R?=?4-MeOC6H4) or P2S5 and the respective alcohol ROH (R?=?myrtanyl, 2-naphthylethyl, myrtenyl, borneol) in toluene. The reaction of phosphorus-1,1-dithiolates 1–4 and Au(tht)Cl, AuClPPh3 or AgNO3 and PPh3 gave rise to gold(I)- and silver(I)-complexes in THF. All compounds have been characterised by elemental analyses, IR, NMR (1H-, 13C- and 31P-) spectroscopy as well as MS measurements. Optical rotation values confirmed the chirality of the compounds. The Compound 4 has been characterized structurally by X-ray crystallography. Results Phosphorus-1,1,-dithiolate compounds were formed as liquids and were treated with suitable amine in order to convert them to their salts 1–4 . They have been successfully characterized spectroscopically (IR, 1H, 13C, 31P NMR) as well as mass spectra. The compound 4 has been also structurally by X-ray crystallography. The compound 4 crystallizes in the orthorhombic space group P2(1)2(1)2(1) with Z?=?4. Compounds containing phosphorus and sulfur donor atoms are excellent ligands due to offering many metal complexes especially group 11–12 metals. The synthesis of gold(I) and silver(I) complexes with chiral phosphorus-1,1,-dithiolate and triphenylphosphine have been described and investigated. Conclusions In the present work, we report the synthesis, charactreization of the chiral phosphorus-1,1-dithiolate ligands and preparing the gold(I) and silver(I) phosphorus-1,1-dithiolate or S-donor with phosphine complexes. The molecular structure of the Compound 4 was determined by X-ray diffraction. Due to an easy synthesis method of phosphorus-1,1-dithiolate compounds and a good complexion reagent, it is possible the improvement of the collecting metallic gold or silver from the minerals. When the more ionic salt of phosphorus-1,1-dithiolate compounds were prepared in this way, the water can be used as a cheap solvent. As a result, it can be an alternatively method for the collecting metallic gold or silver from the minerals in future. PMID:23687921

  5. White phosphorus

    Integrated Risk Information System (IRIS)

    White phosphorus ; CASRN 7723 - 14 - 0 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 Noncarcinogenic

  6. Phosphorus Filter

    USGS Multimedia Gallery

    Tom Kehler, fishery biologist at the U.S. Fish and Wildlife Service's Northeast Fishery Center in Lamar, Pennsylvania, checks the flow rate of water leaving a phosphorus filter column. The USGS has pioneered a new use for acid mine drainage residuals that are currently a disposal challenge, usi...

  7. Phosphorus: Riverine system transport

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The transport and transformation of phosphorus (P) in riverine systems fundamentally affects the outcome of watershed mitigation strategies aimed at curbing downstream eutrophication. Phosphorus transport and transformations in streams and rivers are mediated by physical (sediment deposition and res...

  8. Phosphorus poisoning in waterfowl

    USGS Publications Warehouse

    Coburn, D.R.; DeWitt, J.B.; Derby, J.V., Jr.; Ediger, E.

    1950-01-01

    Black ducks and mallards were found to be highly susceptible to phosphorus poisoning. 3 mg. of white phosphorus per kg. of body weight given in a single dose resulted in death of a black duck in 6 hours. Pathologic changes in both acute and chronic poisoning were studied. Data are presented showing that diagnosis can be made accurately by chemical analysis of stored tissues in cases of phosphorus poisoning.

  9. PHOSPHORUS RECOVERY FROM SEWAGE

    EPA Science Inventory

    Phosphorus is a growth limiting nutrient that is mined from rock ore, refined, used in fertilizers, and discharged to the environment through municipal sewage. The impacts of phosphorus discharge include severe eutrophication of fresh water bodies. The future sustainable use of...

  10. Black Phosphorus Terahertz Photodetectors.

    PubMed

    Viti, Leonardo; Hu, Jin; Coquillat, Dominique; Knap, Wojciech; Tredicucci, Alessandro; Politano, Antonio; Vitiello, Miriam Serena

    2015-10-01

    The first room-temperature terahertz (THz)-frequency nanodetector exploiting a 10 nm thick flake of exfoliated crystalline black phosphorus as an active channel of a field-effect transistor, is devised. By engineering and embedding planar THz antennas for efficient light harvesting, the first technological demonstration of a phosphorus-based active THz device is described. PMID:26270791

  11. Black phosphorus gas sensors.

    PubMed

    Abbas, Ahmad N; Liu, Bilu; Chen, Liang; Ma, Yuqiang; Cong, Sen; Aroonyadet, Noppadol; Köpf, Marianne; Nilges, Tom; Zhou, Chongwu

    2015-05-26

    The utilization of black phosphorus and its monolayer (phosphorene) and few-layers in field-effect transistors has attracted a lot of attention to this elemental two-dimensional material. Various studies on optimization of black phosphorus field-effect transistors, PN junctions, photodetectors, and other applications have been demonstrated. Although chemical sensing based on black phosphorus devices was theoretically predicted, there is still no experimental verification of such an important study of this material. In this article, we report on chemical sensing of nitrogen dioxide (NO2) using field-effect transistors based on multilayer black phosphorus. Black phosphorus sensors exhibited increased conduction upon NO2 exposure and excellent sensitivity for detection of NO2 down to 5 ppb. Moreover, when the multilayer black phosphorus field-effect transistor was exposed to NO2 concentrations of 5, 10, 20, and 40 ppb, its relative conduction change followed the Langmuir isotherm for molecules adsorbed on a surface. Additionally, on the basis of an exponential conductance change, the rate constants for adsorption and desorption of NO2 on black phosphorus were extracted for different NO2 concentrations, and they were in the range of 130-840 s. These results shed light on important electronic and sensing characteristics of black phosphorus, which can be utilized in future studies and applications. PMID:25945545

  12. PHOSPHORUS EXCHANGE IN MARINE PHYTOPLANKTON

    E-print Network

    PHOSPHORUS EXCHANGE IN MARINE PHYTOPLANKTON BY THEODORE R. RICE FISHERY BULLETIN 80 UNITED STATES;ABSTRACT Phosphorus exchange in Nitzschia· clostai'iu.In, isoiated and grown in pure culture, was demunstrated by using rudioactive phosphorus find was ~h()\\\\"n to "IlI'Y with changes in the phosphorus

  13. Phosphorus chemistry on Titan

    NASA Astrophysics Data System (ADS)

    Pasek, Matthew A.; Mousis, Olivier; Lunine, Jonathan I.

    2011-04-01

    Phosphorus is a key element in biology and acts in many critical biochemical functions. The chemistry of phosphorus in the outer Solar System has not yet been quantified, hence the astrobiological relevance of phosphorus to possible life on places like Titan is unconstrained. We evaluate phosphorus chemistry on Titan using a combination of modeling and laboratory techniques. We show that phosphorus chemistry on Titan consists of exogenous phosphates and reduced oxidation state phosphorus compounds, and accretionary phosphine. Accretionary phosphorus is shown to be delivered primarily by rocks and ices in the saturnian sub-nebula, and heating during accretion concentrates phosphine in the crust of Titan. The exogenous compounds are capable of performing biologically-relevant chemistry, however they are active only in environments with substantial liquid water, either pure, or as a mixture with NH 3 or nitrile compounds. In contrast, we show that phosphine is soluble in methane and ethane on Titan's surface, hence phosphine likely participates in the hydrocarbon cycle on Titan. The lack of mobility of phosphate compounds on Titan's surface suggests that if life is present on Titan, it must have a fundamentally different biochemistry than does terrestrial life.

  14. PHYSICAL REVIEW B 86, 035105 (2012) Effect of van der Waals interactions on the structural and elastic properties of black phosphorus

    E-print Network

    Svane, Axel Torstein

    2012-01-01

    and elastic properties of black phosphorus S. Appalakondaiah and G. Vaitheeswaran* Advanced Centre of Research black phosphorus have been investigated using first-principles calculations based on density functional constant is significantly larger than the C11 and C33 parameters, implying that black phosphorus is stiffer

  15. Rethinking early Earth phosphorus geochemistry

    PubMed Central

    Pasek, Matthew A.

    2008-01-01

    Phosphorus is a key biologic element, and a prebiotic pathway leading to its incorporation into biomolecules has been difficult to ascertain. Most potentially prebiotic phosphorylation reactions have relied on orthophosphate as the source of phosphorus. It is suggested here that the geochemistry of phosphorus on the early Earth was instead controlled by reduced oxidation state phosphorus compounds such as phosphite (HPO32?), which are more soluble and reactive than orthophosphates. This reduced oxidation state phosphorus originated from extraterrestrial material that fell during the heavy bombardment period or was produced during impacts, and persisted in the mildly reducing atmosphere. This alternate view of early Earth phosphorus geochemistry provides an unexplored route to the formation of pertinent prebiotic phosphorus compounds, suggests a facile reaction pathway to condensed phosphates, and is consistent with the biochemical usage of reduced oxidation state phosphorus compounds in life today. Possible studies are suggested that may detect reduced oxidation state phosphorus compounds in ancient Archean rocks. PMID:18195373

  16. Phosphorus Centers of Different Hybridization in Phosphaalkene-Substituted Phospholes

    PubMed Central

    Öberg, Elisabet; Orthaber, Andreas; Lescop, Christophe; Réau, Régis; Hissler, Muriel; Ott, Sascha

    2014-01-01

    Phosphole-substituted phosphaalkenes (PPAs) of the general formula Mes*P=C(CH3)–(C4H2P(Ph))–R 5 a–c (Mes*=2,4,6-tBu3Ph; R=2-pyridyl (a), 2-thienyl (b), phenyl (c)) have been prepared from octa-1,7-diyne-substituted phosphaalkenes by utilizing the Fagan–Nugent route. The presence of two differently hybridized phosphorus centers (?2,?3 and ?3,?3) in 5 offers the possibility to selectively tune the HOMO–LUMO gap of the compounds by utilizing the different reactivity of the two phosphorus heteroatoms. Oxidation of 5 a–c by sulfur proceeds exclusively at the ?3,?3-phosphorus atom, thus giving rise to the corresponding thioxophospholes 6 a–c. Similarly, 5 a is selectively coordinated by AuCl at the ?3,?3-phosphorus atom. Subsequent second AuCl coordination at the ?2,?3-phosphorus heteroatom results in a dimetallic species that is characterized by a gold–gold interaction that provokes a change in ? conjugation. Spectroscopic, electrochemical, and theoretical investigations show that the phosphaalkene and the phosphole both have a sizable impact on the electronic properties of the compounds. The presence of the phosphaalkene unit induces a decrease of the HOMO–LUMO gap relative to reference phosphole-containing ? systems that lack a P=C substituent. PMID:24890504

  17. Fractionation of Soil Phosphorus

    Technology Transfer Automated Retrieval System (TEKTRAN)

    An understanding of the qualitative and quantitative information provided by soil phosphorus (P) fractionation methods is important for addressing agronomic and water quality problems, as well as evaluating P biogeochemistry in extreme environments. This chapter provides a schematic overview of and ...

  18. Black Phosphorus RF Transistor

    NASA Astrophysics Data System (ADS)

    Wang, Han; Wang, Xiaomu; Xia, Fengnian; Wang, Luhao; Jiang, Hao; Xia, Qiangfei; Chin, Mattew L.; Dubey, Madan; Han, Shu-Jen

    2015-03-01

    Few-layer and thin film form of layered black phosphorus (BP) has recently emerged as a promising material for applications in high performance thin film electronics and infrared optoelectronics. Layered BP offers a ~ 0.3eV bandgap and high mobility, leading to transistor devices with decent on/off ratio and high on-state current density. Here, we demonstrate the GHz frequency operation of black phosphorus field-effect transistor for the first time. BP transistors demonstrated here show excellent current saturation with an on-off ratio exceeding 2 × 103. The S-parameter characterization is performed for the first time on black phosphorus transistors, giving a 12 GHz short-circuit current-gain cut-off frequency and 20 GHz maximum oscillation frequency in 300 nm channel length devices. A current density in excess of 270 mA/mm and DC transconductance above 180 mS/mm are achieved for hole conductions. The results reveal the promising potential of black phosphorus transistors for enabling the next generation thin film transistor technology that can operate in the multi-GHz frequency range and beyond.

  19. Disorders of phosphorus homeostasis

    PubMed Central

    Lee, Richard; Weber, Thomas J.

    2013-01-01

    Purpose of Review The study of phosphorus physiology and investigations into clinical disorders of phosphorus metabolism has blossomed over the past decade. Recent work has confirmed and further extended our knowledge of basic mechanisms of phosphorus metabolism. Recent findings This review will focus on FGF-23 and Klotho, and on the recent further dissection of their roles in phosphorus and skeletal metabolism. Additionally, this review will detail recent studies that implicate a role for these phosphaturic and vitamin D regulating factors in extraskeletal calcification, including that occurring in soft tissue and vascular beds. Summary These findings in total provide fertile ground for investigations into the cause and treatment of abnormal skeletal and extraskeletal calcification in patients with inherited hypophosphatemic disorders. More importantly, and certainly with wider potential clinical application, these studies likewise imply a role for these factors in the pathogenesis of accelerated cardiovascular disease that occurs in patients with the most common hyperphosphatemic disorder, chronic kidney disease. Future studies are needed to confirm a harmful or possibly even beneficial role for FGF-23 and other factors in these disease states, and to determine whether therapeutic manipulation of these factors does truly affect clinical outcomes in patients with hypo- and hyperphosphatemia. PMID:20962635

  20. Soil test phosphorus and cumulative phosphorus budgets in fertilized grassland.

    PubMed

    Messiga, Aimé Jean; Ziadi, Noura; Jouany, Claire; Virkajärvi, Perttu; Suomela, Raija; Sinaj, Sokrat; Bélanger, Gilles; Stroia, Ciprian; Morel, Christian

    2015-03-01

    We analyzed the linearity of relationships between soil test P (STP) and cumulative phosphorus (P) budget using data from six long-term fertilized grassland sites in four countries: France (Ercé and Gramond), Switzerland (Les Verrières), Canada (Lévis), and Finland (Maaninka and Siikajoki). STP was determined according to existing national guidelines. A linear-plateau model was used to determine the presence of deflection points in the relationships. Deflection points with (x, y) coordinates were observed everywhere but Maaninka. Above the deflection point, a significant linear relationship was obtained (0.33 < r (2) < 0.72) at four sites, while below the deflection point, the relationship was not significant, with a negligible rate of STP decrease. The relationship was not linear over the range of STP encountered at most sites, suggesting a need for caution when using the P budget approach to predict STP changes in grasslands, particularly in situations of very low P fertilization. Our study provides insights and description of a tool to improve global P strategies aimed at maintaining STP at levels adequate for grassland production while reducing the risk of P pollution of water. PMID:25681982

  1. Implications of phosphorus redox geochemistry

    NASA Astrophysics Data System (ADS)

    Pasek, Matthew

    2015-04-01

    Phosphorus is the limiting nutrient in many environments. Until recently, redox changes to phosphorus speciation have been confined to the realm of chemical laboratories as phosphorus was considered to be synonymous with phosphate in the natural environment. The few known phosphorus species with a reduced redox state, such as phosphine gas, were considered novelties. Recent work has revealed a surprising role for low redox state organophosphorus compounds -- the phosphonates -- in biogeochemistry. Additionally, phosphite and hypophosphite (the lower oxyanions of phosphorus) have been identified from natural sources, and microbial genomics suggests these compounds may be ubiquitous in nature. Recent work from our laboratory suggests that reduced phosphorus compounds such as phosphite and hypophosphite may be ubiquitous (Pasek et al. 2014). If so, then these species maybe important in the global phosphorus biogeochemical cycle, and could influence global phosphorus sustainability. Additionally, these compounds could have been relevant on the early earth environment, priming the earth with reactive phosphorus for prebiotic chemistry. Reference: Pasek, M. A., Sampson, J. M., & Atlas, Z. (2014). Redox chemistry in the phosphorus biogeochemical cycle. Proceedings of the National Academy of Sciences, 111(43), 15468-15473.

  2. THE CHEMICAL EVOLUTION OF PHOSPHORUS

    SciTech Connect

    Jacobson, Heather R.; Thanathibodee, Thanawuth; Frebel, Anna; Roederer, Ian U.; Cescutti, Gabriele; Matteucci, Francesca

    2014-12-01

    Phosphorus is one of the few remaining light elements for which little is known about its nucleosynthetic origin and chemical evolution, given the lack of optical absorption lines in the spectra of long-lived FGK-type stars. We have identified a P I doublet in the near-ultraviolet (2135/2136 Å) that is measurable in stars of low metallicity. Using archival Hubble Space Telescope-Space Telescope Imaging Spectrograph spectra, we have measured P abundances in 13 stars spanning –3.3 ? [Fe/H] ? -0.2, and obtained an upper limit for a star with [Fe/H] ? -3.8. Combined with the only other sample of P abundances in solar-type stars in the literature, which spans a range of –1 ? [Fe/H] ? +0.2, we compare the stellar data to chemical evolution models. Our results support previous indications that massive-star P yields may need to be increased by a factor of a few to match stellar data at all metallicities. Our results also show that hypernovae were important contributors to the P production in the early universe. As P is one of the key building blocks of life, we also discuss the chemical evolution of the important elements to life, C-N-O-P-S, together.

  3. The problem with phosphorus

    NASA Astrophysics Data System (ADS)

    Froelich, Phillip N.

    Phosphorus is King of the aquatic plant kingdom.1 Without it there would be no growth, no reproduction, and thus no life.2 This simple principle has been concealed from a generation of aquatic scientists seduced by the powers of the Queen Consort, Nitrogen.3If Phosphorus is King and Nitrogen is Queen, then a naive observer4 of the Chess Queen, then a naive observer4 of the Chess Game of Life might prematurely conclude, after watching the moves unfolding on the board, that the Queen is all powerful and controls the game. She can move both diagonally and laterally across the board5 and travels long distances in one jump.6 Clones can be created from thin air on the back row.7 She literally dances over the board and controls the tempo of the game.8 A game without a dominant Queen is rare.9

  4. Multiple phosphorus chemical sites in heavily phosphorus-doped diamond

    SciTech Connect

    Okazaki, Hiroyuki; Yoshida, Rikiya; Muro, Takayuki; Nakamura, Tetsuya; Hirai, Masaaki; Kato, Hiromitsu; Yamasaki, Satoshi; Takano, Yoshihiko; Ishii, Satoshi; Oguchi, Tamio

    2011-02-21

    We have performed high-resolution core level photoemission spectroscopy on a heavily phosphorus (P)-doped diamond film in order to elucidate the chemical sites of doped-phosphorus atoms in diamond. P 2p core level study shows two bulk components, providing spectroscopic evidence for multiple chemical sites of doped-phosphorus atoms. This indicates that only a part of doped-phosphorus atoms contribute to the formation of carriers. From a comparison with band calculations, possible origins for the chemical sites are discussed.

  5. Assessment of Phosphorus Retention in Irrigation Laterals

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Irrigation laterals transport irrigation return flow, including water, sediment, and nutrients, back to surface water bodies. Phosphorus transformations during transport can affect both phosphorus bioavailability and the best management practices selected to minimize phosphorus inputs to waters of ...

  6. Black Phosphorus Boron Nitride Heterostructures

    NASA Astrophysics Data System (ADS)

    Gillgren, Nathaniel; Barlas, Yafis; Shi, Yanmeng; Yang, Jiawei; Taniguchi, Takashi; Lau, Chun Ning (Jeanie)

    2015-03-01

    There has been significant recent interest in black phosphorus as a candidate for future electronics applications, as it possesses both a layered-tunable band gap and a relatively high mobility (compared to other 2D candidates). However, black phosphorus' degradation in ambient conditions constitutes a major road block in future applications. As a potential solution for this problem we explore the effects of encapsulating black phosphorus between hexagonal boron nitride. We will present the effects of this heterostructure on both the stability and transport properties of thin black phosphorus devices.

  7. Formation of Stable Phosphorus-Carbon Bond for Enhanced Performance in Black Phosphorus Nanoparticle-Graphite Composite

    E-print Network

    Cui, Yi

    Formation of Stable Phosphorus-Carbon Bond for Enhanced Performance in Black Phosphorus of electrical contact. Using the conducting allotrope of phosphorus, "black phosphorus" as starting materials, here we fabricated composites of black phosphorus nanoparticle-graphite by mechanochemical reaction

  8. Preparation of high purity phosphorus

    DOEpatents

    Rupp, Arthur F. (Oak Ridge, TN); Woo, David V. (Knoxville, TN)

    1981-01-01

    High purity phosphorus and phosphorus compounds are prepared by first reacting H.sub.3 PO.sub.4 with a lead compound such as PbO to form Pb.sub.3 (PO.sub.4).sub.2. The Pb.sub.3 (PO.sub.4).sub.2 is reduced with H.sub.2 at a temperature sufficient to form gaseous phosphorus which can be recovered as a high purity phosphorus product. Phosphorus compounds can be easily prepared by reacting the phosphorus product with gaseous reactants. For example, the phosphorus product is reacted with gaseous Cl.sub.2 to form PCl.sub.5. PCl.sub.5 is reduced to PCl.sub.3 by contacting it in the gaseous phase with solid elemental phosphorus. POCl.sub.3 can be prepared by contacting PCl.sub.5 in the gaseous phase with solid P.sub.2 O.sub.5. The general process is particularly suitable for the preparation of radiophosphorus compounds.

  9. The Chemical Evolution of Phosphorus

    NASA Astrophysics Data System (ADS)

    Jacobson, Heather R.; Thanathibodee, Thanawuth; Frebel, Anna; Roederer, Ian U.; Cescutti, Gabriele; Matteucci, Francesca

    2014-12-01

    Phosphorus is one of the few remaining light elements for which little is known about its nucleosynthetic origin and chemical evolution, given the lack of optical absorption lines in the spectra of long-lived FGK-type stars. We have identified a P I doublet in the near-ultraviolet (2135/2136 Å) that is measurable in stars of low metallicity. Using archival Hubble Space Telescope-Space Telescope Imaging Spectrograph spectra, we have measured P abundances in 13 stars spanning -3.3 <= [Fe/H] <= -0.2, and obtained an upper limit for a star with [Fe/H] ~ -3.8. Combined with the only other sample of P abundances in solar-type stars in the literature, which spans a range of -1 <= [Fe/H] <= +0.2, we compare the stellar data to chemical evolution models. Our results support previous indications that massive-star P yields may need to be increased by a factor of a few to match stellar data at all metallicities. Our results also show that hypernovae were important contributors to the P production in the early universe. As P is one of the key building blocks of life, we also discuss the chemical evolution of the important elements to life, C-N-O-P-S, together. Based on observations made with the NASA/ESA Hubble Space Telescope, obtained at the Space Telescope Science Institute, which is operated by the Association of Universities for Research in Astronomy, Inc., under NASA contract NAS 5-26555. This work is supported through program AR-13246. Other portions of this work are based on data gathered with the 6.5 m Magellan Telescopes located at Las Campanas Observatory, Chile, and the McDonald Observatory of the University of Texas at Austin.

  10. Prebiotic phosphorus chemistry reconsidered

    NASA Technical Reports Server (NTRS)

    Schwartz, A. W.; Orgel, L. E. (Principal Investigator)

    1997-01-01

    The available evidence indicates that the origin of life on Earth certainly occurred earlier than 3.5 billion years ago and perhaps substantially earlier. The time available for the chemical evolution which must have preceded this event is more difficult to estimate. Both endogenic and exogenic contributions to chemical evolution have been considered; i.e., from chemical reactions in a primitive atmosphere, or by introduction in the interiors of comets and/or meteorites. It is argued, however, that the phosphorus chemistry of Earth's earliest hydrosphere, whether primarily exogenic or endogenic in origin, was most likely dominated by compounds less oxidized than phosphoric acid and its esters. A scenario is presented for the early production of a suite of reactive phosphonic acid derivatives, the properties of which may have foreshadowed the later appearance of biophosphates.

  11. Phosphorus Dynamic in Wetlands

    NASA Astrophysics Data System (ADS)

    Pant, H. K.

    2010-12-01

    The projected greater warming at higher/northern latitudes in the coming decades due to global climatic changes can mineralize substantial amount of the organic matter and supply massive amount of phosphorus (P) to the water column, and cause the collapse of freshwater wetlands. Thus, the rates and duration of organic matter accumulations/decompositions under rising global temperatures are critical determinants of how a freshwater wetland functions as an ecological unit within a landscape. Phosphorus is a limiting nutrient and a primary controller of eutrophication. Once the external P loads are curtailed, internal P regeneration, resulting from decompositions of detritus and soil/sediment organic matter determine the productivity, as well as the water quality of a wetland. Thus, global rise in temperature not only causes hydro-climatic fluctuations but can also change the composition of aquatic/semi-aquatic communities, in turn, could lead to adverse effect on human food chain to collapse of the ecosystem. While P enrichment may lead to immediate algal blooms in wetlands/aquatic systems, decreased in P input from external sources may not be able to stop the blooms for a considerable period of time depending on the P loading from within. The extent of P mineralization under changing conditions, enzymatic hydrolysis, and estimation of different P pools using 31P NMR in sediments and the water columns showed that the stability and bioavailability of P can greatly be influenced by rise in temperature and fluctuations in water level, thus, are crucial in determining the fate of the freshwater wetlands.

  12. The renaissance of black phosphorus

    E-print Network

    Ling, Xi

    One hundred years after its first successful synthesis in the bulk form in 1914, black phosphorus (black P) was recently rediscovered from the perspective of a 2D layered material, attracting tremendous interest from ...

  13. THE CHEMICAL EVOLUTION OF PHOSPHORUS

    E-print Network

    Jacobson, Heather

    Phosphorus is one of the few remaining light elements for which little is known about its nucleosynthetic origin and chemical evolution, given the lack of optical absorption lines in the spectra of long-lived FGK-type ...

  14. The Relevance of Phosphorus and Iron Chemistry to the Recovery of Phosphorus from Wastewater: A Review.

    PubMed

    Wilfert, Philipp; Kumar, Prashanth Suresh; Korving, Leon; Witkamp, Geert-Jan; van Loosdrecht, Mark C M

    2015-08-18

    The addition of iron is a convenient way for removing phosphorus from wastewater, but this is often considered to limit phosphorus recovery. Struvite precipitation is currently used to recover phosphorus, and this approach has attracted much interest. However, it requires the use of enhanced biological phosphorus removal (EBPR). EBPR is not yet widely applied and the recovery potential is low. Other phosphorus recovery methods, including sludge application to agricultural land or recovering phosphorus from sludge ash, also have limitations. Energy-producing wastewater treatment plants increasingly rely on phosphorus removal using iron, but the problem (as in current processes) is the subsequent recovery of phosphorus from the iron. In contrast, phosphorus is efficiently mobilized from iron by natural processes in sediments and soils. Iron-phosphorus chemistry is diverse, and many parameters influence the binding and release of phosphorus, including redox conditions, pH, presence of organic substances, and particle morphology. We suggest that the current poor understanding of iron and phosphorus chemistry in wastewater systems is preventing processes being developed to recover phosphorus from iron-phosphorus rich wastes like municipal wastewater sludge. Parameters that affect phosphorus recovery are reviewed here, and methods are suggested for manipulating iron-phosphorus chemistry in wastewater treatment processes to allow phosphorus to be recovered. PMID:25950504

  15. Effects of Aspergillus fumigatus phytase on phosphorus digestibility, phosphorus excretion, bone strength and performance in pigs.

    PubMed

    Simões Nunes, C; Guggenbuhl, P

    1998-01-01

    Phytic-phosphorus has a very low bioavailability for monogastric animals and the non-utilized mineral contributes to the phosphorus (P) pollution problems. Phytases may ameliorate phytic-P antinutritive properties. However, phytases are very sensitive to the pelleting temperature commonly used for compound feed production and thus the challenge to produce a more thermostable phytase is very important. Pure Aspergillus fumigatus phytase (AFP) has the ability to refold into a native-like fully active structure after heat denaturation (20 min at 90 degrees C). The aim of the present work was to evaluate in vitro (in feed) and in vivo in young and in growing-finishing pigs the effects of AFP included in the feed at a level of 500 U/kg. Feed supplementation with AFP resulted in an in vitro phosphorus release of about three times higher than that obtained from the basal diets, irrespective of the pH value used for the determination (5.5 or 7). When the supplemented feed was steam pelleted at about 84 degrees C, the free P obtained after incubation at pH 5.5 represented 53% on an average of that obtained from the corresponding mash diets. The phytic-P-rich diets systematically induced hypophosphataemia, hypercalcaemia and hyperphosphatasaemia. The normal blood levels of P, Ca and alkaline phosphatase were restored by AFP. P apparent digestibility was significantly higher for the AFP diet (52.8 versus 30.8%). The improvement in Ca digestibility was not statistically significant. In all three in vivo experiments, AFP significantly decreased the P concentration in faeces (between 13 and 33%) as well as increased the growth rate and decreased the feed conversion ratio. Bone strength was significantly higher in the growing-fattening pigs fed on the AFP diet. PMID:9795986

  16. Phosphorus Flamethrower: A Demonstration Using Red and White Allotropes of Phosphorus

    ERIC Educational Resources Information Center

    Golden, Melissa L.; Person, Eric C.; Bejar, Miriam; Golden, Donnie R.; Powell, Jonathan M.

    2010-01-01

    A demonstration was created to display the unique behavior of a familiar element, phosphorus, and to make chemistry more accessible to the introductory student. The common allotropes of phosphorus and their reactivity are discussed. In this demonstration, the white allotrope of phosphorus is synthesized from the red phosphorus obtained from a…

  17. Phosphorus: From the Stars to Land & Sea

    E-print Network

    Cummins, Christopher C.

    The chemistry of the element phosphorus offers a window into the diverse field of inorganic chemistry. Fundamental investigations into some simple molecules containing phosphorus reveal much about the ramifications of this ...

  18. Fire-Resistant Polyimides Containing Phosphorus

    NASA Technical Reports Server (NTRS)

    Mikroyannidis, J.

    1986-01-01

    Limiting oxygen index increased. Copolyimide with a group containing phosphorus synthesized from 1-2,4-diaminobenzene, m-phenylenediamine, and tetracarboxylic dianhydride. Copolymer more fire resistant than corresponding polyimide without phosphorus.

  19. Cholestatic presentation of yellow phosphorus poisoning.

    PubMed

    Lakshmi, C P; Goel, Amit; Basu, Debdatta

    2014-01-01

    Yellow phosphorus, a component of certain pesticide pastes and fireworks, is well known to cause hepatotoxicity. Poisoning with yellow phosphorus classically manifests with acute hepatitis leading to acute liver failure which may need liver transplantation. We present a case of yellow phosphorus poisoning in which a patient presented with florid clinical features of cholestasis highlighting the fact that cholestasis can rarely be a presenting feature of yellow phosphorus hepatotoxicity. PMID:24554916

  20. Phosphorus Risk Index Quantitative vs. Qualitative

    E-print Network

    Phosphorus Risk Index Quantitative vs. Qualitative Which is Appropriate? Which is Best? Biosystems to estimate the level of risk to people or the environment Risk ­ Phosphorus Risk Index (Storm) ­ Probability that a specific phosphorus concentration and/or loading to a receiving water body will cause an adverse response

  1. GROUNDWATER POLLUTION BY PHOSPHORUS FERTILIZERS

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Phosphorus (P) is a primary nutrient necessary for plant growth. When soil P level is below what is needed for plant needs, P is supplied to the soil by the addition of P fertilizer or organic residuals (i.e., manure). Because of P fertilizer use in the past few decades or application of manure, a g...

  2. PHOSPHORUS FORMS AND PLANT AVAILABILITY

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Land-applied organic wastes can lead to accumulation of phosphorus (P) in soil and can contribute to nonpoint source pollution of surface waters. The objective of this study was to investigate soil test P changes due to various P sources in an INCUBATION STUDY and to determine plant available P fro...

  3. Major Minerals - Calcium, Magnesium, Phosphorus

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Calcium, magnesium and phosphorus are essential elements critically important for the function of the musculoskeletal system, including the formation and transduction of energy and the maintenance of healthy bone. The major calcium concern for physically active healthy middle-aged adults is to consu...

  4. MEASUREMENT OF PHOSPHORUS IN WATER

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Phosphorus (P) is an essential nutrient for growth and development of algae and other aquatic plants. However, P can cause water pollution if sufficient concentration (25 to 100 µg total P L-1, eutrophic condition) is present in water. Eutrophication (nutrient-rich condition) can significantly incre...

  5. Gettering Silicon Wafers with Phosphorus

    NASA Technical Reports Server (NTRS)

    Daiello, R. V.

    1983-01-01

    Silicon wafers subjected to gettering in phosphorus atmosphere have longer diffusion lengths and higher solar-cell efficiencies than untreated wafers. Gettering treatment improves properties of solar cells manufactured from impure silicon and is compatible with standard solar-cell processing.

  6. The Galactic evolution of phosphorus

    NASA Astrophysics Data System (ADS)

    Caffau, E.; Bonifacio, P.; Faraggiana, R.; Steffen, M.

    2011-08-01

    Context. As a galaxy evolves, its chemical composition changes and the abundance ratios of different elements are powerful probes of the underlying evolutionary processes. Phosphorous is an element whose evolution has remained quite elusive until now, because it is difficult to detect in cool stars. The infrared weak P i lines of the multiplet 1, at 1050-1082 nm, are the most reliable indicators of the presence of phosphorus. The availability of CRIRES at VLT has permitted access to this wavelength range in stellar spectra. Aims: We attempt to measure the phosphorus abundance of twenty cool stars in the Galactic disk. Methods: The spectra are analysed with one-dimensional model-atmospheres computed in local thermodynamic equilibrium (LTE). The line formation computations are performed assuming LTE. Results: The ratio of phosphorus to iron behaves similarly to sulphur, increasing towards lower metallicity stars. Its ratio with respect to sulphur is roughly constant and slightly larger than solar, [P/S] = 0.10 ± 0.10. Conclusions: We succeed in taking an important step towards the understanding of the chemical evolution of phosphorus in the Galaxy. However, the observed rise in the P/Fe abundance ratio is steeper than predicted by Galactic chemical evolution model developed by Kobayashi and collaborators. Phosphorus appears to evolve differently from the light odd-Z elements sodium and aluminium. The constant value of [P/S] with metallicity implies that P production is insensitive to the neutron excess, thus processes other than neutron captures operate. We suggest that proton captures on 30Si and ? captures on 27Al are possibilities to investigate. We see no clear distinction between our results for stars with planets and stars without any detected planet. Based on observations obtained with the CRIRES spectrograph at ESO-VLT Antu 8.2 m telescope at Paranal, Programme 386.D-0130, P.I. E. Caffau.

  7. Phosphorus doping a semiconductor particle

    DOEpatents

    Stevens, G.D.; Reynolds, J.S.

    1999-07-20

    A method of phosphorus doping a semiconductor particle using ammonium phosphate is disclosed. A p-doped silicon sphere is mixed with a diluted solution of ammonium phosphate having a predetermined concentration. These spheres are dried with the phosphorus then being diffused into the sphere to create either a shallow or deep p-n junction. A good PSG glass layer is formed on the surface of the sphere during the diffusion process. A subsequent segregation anneal process is utilized to strip metal impurities from near the p-n junction into the glass layer. A subsequent HF strip procedure is then utilized to removed the PSG layer. Ammonium phosphate is not a restricted chemical, is inexpensive, and does not pose any special shipping, handling, or disposal requirement. 1 fig.

  8. Engineering phosphorus metabolism in plants to produce a dual fertilization and weed control system.

    PubMed

    López-Arredondo, Damar Lizbeth; Herrera-Estrella, Luis

    2012-09-01

    High crop yields depend on the continuous input of orthophosphate (PO(4)(?3))-based fertilizers and herbicides. Two major challenges for agriculture are that phosphorus is a nonrenewable resource and that weeds have developed broad herbicide resistance. One strategy to overcome both problems is to engineer plants to outcompete weeds and microorganisms for limiting resources, thereby reducing the requirement for both fertilizers and herbicides. Plants and most microorganisms are unable to metabolize phosphite (PO(3)(?3)), so we developed a dual fertilization and weed control system by generating transgenic plants that can use phosphite as a sole phosphorus source. Under greenhouse conditions, these transgenic plants require 30–50% less phosphorus input when fertilized with phosphite to achieve similar productivity to that obtained by the same plants using orthophosphate fertilizer and, when in competition with weeds, accumulate 2–10 times greater biomass than when fertilized with orthophosphate. PMID:22922674

  9. The Galactic evolution of phosphorus

    E-print Network

    Caffau, E; Faraggiana, R; Steffen, M

    2011-01-01

    As a galaxy evolves, its chemical composition changes and the abundance ratios of different elements are powerful probes of the underlying evolutionary processes. Phosphorous is an element whose evolution has remained quite elusive until now, because it is difficult to detect in cool stars. The infrared weak P I lines of the multiplet 1, at 1050-1082 nm, are the most reliable indicators of the presence of phosphorus. The availability of CRIRES at VLT has permitted access to this wavelength range in stellar spectra.We attempt to measure the phosphorus abundance of twenty cool stars in the Galactic disk. The spectra are analysed with one-dimensional model-atmospheres computed in Local Thermodynamic Equilibrium (LTE). The line formation computations are performed assuming LTE. The ratio of phosphorus to iron behaves similarly to sulphur, increasing towards lower metallicity stars. Its ratio with respect to sulphur is roughly constant and slightly larger than solar, [P/S]=0.10+- 0.10. We succeed in taking an impo...

  10. Phosphorus and Water Quality Paradox

    NASA Astrophysics Data System (ADS)

    Pant, H. K.

    2008-12-01

    Paradoxically, phosphorus (P) is one of the major nutrients for higher agricultural production, as well as it causes eutrophication/algal blooms in aquatic and semi-aquatic systems. Phosphorus loadings from agricultural/urban runoffs into lakes and rivers are becoming a global concern for the protection of water quality. Artificial wetlands are considered as a low cost alternative for treating wastewater including removal of P from sources such as agricultural and urban runoffs. However, the selection of the construction site may well determine the effectiveness of these wetlands. Studies show that P transformations in sediments/ soils are crucial for P sequestration in a wetland rather than the amounts of native P. Using 31Phosphorus Nuclear Magnetic Resonance Spectroscopy (31P NMR), previously unreported an active organic P form, phosphoarginine, was identified, and the study indicates that abandonment of P impacted sites may not solve the P loading problem to the water bodies as the organic P compounds would not be as stable as they were thought, thus, can play a detrimental role in eutrophication of water bodies, after all.

  11. Phosphorus Cycling Through Space and Time

    NASA Astrophysics Data System (ADS)

    Filippelli, Gabriel

    2014-05-01

    The cycling of phosphorus, a biocritical element in short supply in nature, is an important Earth system process. Variations in the phosphorus cycle have occurred in the past. For example, the rapid uplift of the Himalayan-Tibet Plateau increased chemical weathering, which led to enhanced input of phosphorus to the oceans. This drove the late Miocene "biogenic bloom." On glacial timescales, phosphorus is quite dynamic. In terrestrial systems, phosphorus soil mineralogy alters rapidly in response to early soil development, and ultimately becomes limited to plant availability in many setting. In marine systems, the loss of the substantial continental margin sink for reactive P occurs during glacial sea-level lowstands, effectively concentrating phosphorus in the deep sea. Finally, in the modern, the phosphorus cycle is dominated by human activity and agriculture, which causes unwanted pollution due to high phosphorus loading and itself poses significant concerns about the ultimate future availability of this nutrient to feed an expanding human population. This presentation will cover several critical components of the phosphorus cycle, including terrestrial and marine systems, through the lens of geologic time. This perspective reveals the significant changes that have occurred in the availability of phosphorus through time, and how other biogeochemical systems have responded to these changes. Furthermore, the perspective provides some sobering insights into the mechanisms behind the concentration of marine phosphorus into viable sources of phosphate rock. The rarity of high-quality phosphate rock deposits and the limitation of easily minable reserves are becoming critical, as the human demand for fertilizer phosphorus far outstrips the geologic rate of replacement and few prospects exist for new discoveries of phosphate rock.

  12. Assessing Long Term Impact of Phosphorus Fertilization on Phosphorus Loadings Using AnnAGNPS

    EPA Science Inventory

    High phosphorus (P) loss from agricultural fields has been an environmental concern because of potential water quality problems in streams and lakes. To better understand the process of P loss and evaluate the different phosphorus fertilization rates on phosphorus losses, the US...

  13. 40 CFR 721.2752 - Epoxy resin containing phosphorus (generic).

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ...2014-07-01 false Epoxy resin containing phosphorus (generic). 721.2752 Section...721.2752 Epoxy resin containing phosphorus (generic). (a) Chemical substance...generically as an epoxy resin containing phosphorus (PMN P-00-912) is subject...

  14. 40 CFR 721.2752 - Epoxy resin containing phosphorus (generic).

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ...2012-07-01 false Epoxy resin containing phosphorus (generic). 721.2752 Section...721.2752 Epoxy resin containing phosphorus (generic). (a) Chemical substance...generically as an epoxy resin containing phosphorus (PMN P-00-912) is subject...

  15. 40 CFR 721.2752 - Epoxy resin containing phosphorus (generic).

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ...2010-07-01 false Epoxy resin containing phosphorus (generic). 721.2752 Section...721.2752 Epoxy resin containing phosphorus (generic). (a) Chemical substance...generically as an epoxy resin containing phosphorus (PMN P-00-912) is subject...

  16. 40 CFR 721.2752 - Epoxy resin containing phosphorus (generic).

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ...2011-07-01 false Epoxy resin containing phosphorus (generic). 721.2752 Section...721.2752 Epoxy resin containing phosphorus (generic). (a) Chemical substance...generically as an epoxy resin containing phosphorus (PMN P-00-912) is subject...

  17. 21 CFR 862.1580 - Phosphorus (inorganic) test system.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ...2013-04-01 2013-04-01 false Phosphorus (inorganic) test system. 862...Chemistry Test Systems § 862.1580 Phosphorus (inorganic) test system. (a) Identification. A phosphorus (inorganic) test system is a...

  18. 21 CFR 862.1580 - Phosphorus (inorganic) test system.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ...2014-04-01 2014-04-01 false Phosphorus (inorganic) test system. 862...Chemistry Test Systems § 862.1580 Phosphorus (inorganic) test system. (a) Identification. A phosphorus (inorganic) test system is a...

  19. ORIGINAL PAPER Benthic sediment influence on dissolved phosphorus

    E-print Network

    Lottig, Noah R.

    ORIGINAL PAPER Benthic sediment influence on dissolved phosphorus concentrations in a headwater with inorganic sedi- ment particles through sorption reactions in streams. Collectively, this phosphorus (P determining ambi- ent stream P concentrations. Keywords Phosphorus retention Á Sediments Á Equilibrium

  20. 21 CFR 862.1580 - Phosphorus (inorganic) test system.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ...2011-04-01 2011-04-01 false Phosphorus (inorganic) test system. 862...Chemistry Test Systems § 862.1580 Phosphorus (inorganic) test system. (a) Identification. A phosphorus (inorganic) test system is a...

  1. 40 CFR 721.2752 - Epoxy resin containing phosphorus (generic).

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ...2013-07-01 false Epoxy resin containing phosphorus (generic). 721.2752 Section...721.2752 Epoxy resin containing phosphorus (generic). (a) Chemical substance...generically as an epoxy resin containing phosphorus (PMN P-00-912) is subject...

  2. Energy and phosphorus recovery from black water.

    PubMed

    de Graaff, M S; Temmink, H; Zeeman, G; Buisman, C J N

    2011-01-01

    Source-separated black water (BW) (toilet water) containing 38% of the organic material and 68% of the phosphorus in the total household waste (water) stream including kitchen waste, is a potential source for energy and phosphorus recovery. The energy recovered, in the form of electricity and heat, is more than sufficient for anaerobic treatment, nitrogen removal and phosphorus recovery. The phosphorus balance of an upflow anaerobic sludge blanket reactor treating concentrated BW showed a phosphorus conservation of 61% in the anaerobic effluent. Precipitation of phosphate as struvite from this stream resulted in a recovery of 0.22 kgP/p/y, representing 10% of the artificial phosphorus fertiliser production in the world. The remaining part of the phosphorus ended up in the anaerobic sludge, mainly due to precipitation (39%). Low dilution and a high pH favour the accumulation of phosphorus in the anaerobic sludge and this sludge could be used as a phosphorus-enriched organic fertiliser, provided that it is safe regarding heavy metals, pathogens and micro-pollutants. PMID:22049776

  3. Solar production of elemental phosphorus. Final report

    SciTech Connect

    Whaley, T.P.; Yudow, B.D.; Schreiber, J.D.

    1981-11-01

    A project is described which was to determine the technical feasibility of using a solar furnace to produce elemental phosphorus and to provide guidelines for future reactor designs. A laboratory program showed that elemental phosphorus may be produced by heating an intimate mixture of phosphate rock, silica, and carbon black to 1300/sup 0/ to 1500/sup 0/C and sweeping the phosphorus vapors from the reactor with argon. Phosphorus vapors are bubbled through a copper sulfate solution to minimize any potential exposure of personnel. Four successful solar furnace runs at the White Sands Solar Facility are reported. The design and testing of the solar receiver/reactor are discussed. (LEW)

  4. Sources of phosphorus to the Carson River upstream from Lahontan Reservoir, Nevada and California, Water Years 2001-02

    USGS Publications Warehouse

    Alvarez, Nancy L.; Seiler, Ralph L.

    2004-01-01

    Discharge of treated municipal-sewage effluent to the Carson River in western Nevada and eastern California ceased by 1987 and resulted in a substantial decrease in phosphorus concentrations in the Carson River. Nonetheless, concentrations of total phosphorus and suspended sediment still commonly exceed beneficial-use criteria established for the Carson River by the Nevada Division of Environmental Protection. Potential sources of phosphorus in the study area include natural inputs from undisturbed soils, erosion of soils and streambanks, construction of low-head dams and their destruction during floods, manure production and grazing by cattle along streambanks, drainage from fields irrigated with streamwater and treated municipal-sewage effluent, ground-water seepage, and urban runoff including inputs from golf courses. In 2000, the U.S. Geological Survey (USGS), in cooperation with Carson Water Subconservancy District, began an investigation with the overall purpose of providing managers and regulators with information necessary to develop and implement total maximum daily loads for the Carson River. Two specific goals of the investigation were (1) to identify those reaches of the Carson River upstream from Lahontan Reservoir where the greatest increases in phosphorus and suspended-sediment concentrations and loading occur, and (2) to identify the most important sources of phosphorus within the reaches of the Carson River where the greatest increases in concentration and loading occur. Total-phosphorus concentrations in surface-water samples collected by USGS in the study area during water years 2001-02 ranged from <0.01 to 1.78 mg/L and dissolved-orthophosphate concentrations ranged from <0.01 to 1.81 mg/L as phosphorus. In streamflow entering Carson Valley from headwater areas in the East Fork Carson River, the majority of samples exceeding the total phosphorus water-quality standard of 0.1 mg/L occur during spring runoff (March, April, and May) when suspended-sediment concentrations are high. Downstream from Carson Valley, almost all samples exceed the water-quality standard, with the greatest concentrations observed during spring and summer months. Estimated annual total-phosphorus loads ranged from 1.33 tons at the West Fork Carson River at Woodfords to 43.41 tons at the Carson River near Carson City during water years 2001-02. Loads are greatest during spring runoff, followed by fall and winter, and least during the summer, which corresponds to the amount of streamflow in the Carson River. The estimated average annual phosphorus load entering Carson Valley was 21.9 tons; whereas, the estimated average annual phosphorus load leaving Carson Valley was 37.8 tons, for an annual gain in load across Carson Valley of 15.9 tons. Thus, about 58 percent of the total-phosphorus load leaving Carson Valley on an annual basis could be attributed to headwater reaches upstream from Carson Valley. During spring and summer (April 1-September 30) an average of 85 percent of the total-phosphorus load leaving Carson Valley could be attributed to headwater reaches. During fall and winter (October 1-March 31) only 17 percent of the phosphorus load leaving Carson Valley could be attributed to headwater reaches. The composition of the phosphorus changes during summer from particulate phosphorus entering Carson Valley to dissolved orthophosphate leaving Carson Valley. Particulate phosphorus entering Carson Valley could be settling out when water is applied to fields and be replaced by dissolved orthophosphate from other sources. Alternatively, the particulate phosphorus could be converted to dissolved orthophosphate as it travels across Carson Valley. Data collected during the study are not sufficient to distinguish between the two possibilities. Eagle Valley and Dayton-Churchill Valleys may act as sinks for phosphorus. On an annual basis, during water years 2001-02, about 90 percent of the phosphorus entering Eagle Valley left the

  5. Availability of phosphorus from selected inorganic phosphate to juvenile abalone, Haliotis discus hannai ino.

    NASA Astrophysics Data System (ADS)

    Bei-Ping, Tan; Kang-Sen, Mai; Wei, Xu

    2002-06-01

    The availability of phosphorus to juvenile abalone, Haliotis discus hannai from primary, secondary and tertiary calcium phosphate, primary sodium or potassium phosphate separately or in combination was determined in a 120-day feeding trial. Seven semi-purified diets were formulated to contain relatively constant dietary phosphorus, ranging from 0.78%-0.82%. The concentrations of dietary phosphorus were presumed to be slightly below the requirement for abalone. A brown alga, Laminaria japonica, was used as a control diet. Abalone juveniles of silimar size (average weight 1.18 g; average shell length 18.74 mm) were distributed in a single-pass, flow-through system using a completely randomized design with eight treatments and three replicates each treatment. The survival ranged from 71.1% to 81.1%, and was not significantly (P>0.05) related to dietary treatment. However, the weight gain rate (41.72%-65.02%), daily increment in shell length (36.87-55.07 ?m) and muscle RNA-DNA ratio (3.44-4.69) were significantly (P<0.05) affected by dietary treatment. Soft body alkaline phosphatase activity (10.9-19.8 U/g wet tissue) and carcass levels of lipid (7.71%-9.33%) and protein (46.68%-49.35%) were significantly (P<0.05) responsive to available phosphorus of the diets. Dietary treatment had significant effect (P<0.05) on concentrations of phosphorus in the whole body (WB) and soft body (SB). Apparent digestibility coefficients (45%-97%) of phosphorus were also significantly (P<0.05) different between dietary treatments. The results indicated that among these inorganic compounds, primary calcium, potassium and sodium phosphates separately or in combination could be utilized effectively by juvenile abalone as dietary phosphorus sources (availability ranging from 87%-97%). However, secondary and tertiary calcium phosphates were found to be low in availability, the values being 45% and 77%, repectively.

  6. Availability of phosphorus from selected inorganic phosphate to juvenile abalone, Haliotis discus hannai ino.

    NASA Astrophysics Data System (ADS)

    Tan, Bei-Ping; Mai, Kang-Sen; Xu, Wei

    2002-06-01

    The availability of phosphorus to juvenile abalone, Haliotis discus hannai from primary, secondary and tertiary calcium phosphate, primary sodium or potassium phosphate separately or in combination was determined in a 120-day feeding trial. Seven semi-purified diets were formulated to contain relatively constant dietary phosphorus, ranging from 0.78% 0.82%. The concentrations of dietary phosphorus were presumed to be slightly below the requirement for abalone. A brown alga, Laminaria japonica, was used as a control diet. Abalone juveniles of silimar size (average weight 1.18 g; average shell length 18.74 mm) were distributed in a single-pass, flow-through system using a completely randomized design with eight treatments and three replicates each treatment. The survival ranged from 71.1% to 81.1%, and was not significantly (P>0.05) related to dietary treatment. However, the weight gain rate (41.72% 65.02%), daily increment in shell length (36.87 55.07 ?m) and muscle RNA-DNA ratio (3.44 4.69) were significantly (P<0.05) affected by dietary treatment. Soft body alkaline phosphatase activity (10.9 19.8 U/g wet tissue) and carcass levels of lipid (7.71% 9.33%) and protein (46.68% 49.35%) were significantly (P<0.05) responsive to available phosphorus of the diets. Dietary treatment had significant effect (P<0.05) on concentrations of phosphorus in the whole body (WB) and soft body (SB). Apparent digestibility coefficients (45% 97%) of phosphorus were also significantly (P<0.05) different between dietary treatments. The results indicated that among these inorganic compounds, primary calcium, potassium and sodium phosphates separately or in combination could be utilized effectively by juvenile abalone as dietary phosphorus sources (availability ranging from 87% 97%). However, secondary and tertiary calcium phosphates were found to be low in availability, the values being 45% and 77%, repectively.

  7. PHOSPHORUS IN ALUM AMENDED POULTRY LITTER SYSTEMS: DISTRIBUTION, SPECIATION, AND

    E-print Network

    Sparks, Donald L.

    PHOSPHORUS IN ALUM AMENDED POULTRY LITTER SYSTEMS: DISTRIBUTION, SPECIATION, AND INTERACTIONS;PHOSPHORUS IN ALUM AMENDED POULTRY LITTER SYSTEMS: DISTRIBUTION, SPECIATION, AND INTERACTIONS WITH ALUMINUM

  8. Phosphorus release in aerobic sludge digestion.

    PubMed

    Ju, Lu-Kwang; Shah, Hemant K; Porteous, Jim

    2005-01-01

    The objectives of this study are to examine the phosphorus release in aerobic sludge digestion and to better understand its governing mechanisms. In this study, phosphorus release was examined using the secondary sludge from both conventional and biological nutrient removal processes. The experiments were carried out at room temperature (22 +/- 2 degrees C), with or without automatic control of pH (4.5 to 7.8), and under three aeration schemes: fully aerobic (dissolved oxygen [DO] at 3 to 4 mg/L), low DO (0.2 to 0.8 mg/L), and cyclic (with alternate on/off aeration). The released phosphorus concentrations were 20 to 80 mg/L for the conventional sludge and 60 to 130 mg/L for the biophosphorus sludge. Higher phosphorus release also occurred at low pH (<6.0). As for the effect of DO, fully aerobic digestion caused higher phosphorus release than the low-DO and cyclic operations. For better understanding, the solid phosphorus in sludge was conceptually categorized into three forms: inorganic phosphorus precipitates, organic cellular phosphorus, and polyphosphate (poly-P) in polyphosphate-accumulating organisms. Dissolution of inorganic phosphorus precipitates is controlled by physical and chemical conditions, with pH being the most important in this study. Lowering the pH to 4 to 6 clearly promoted the release of inorganic phosphorus. Polyphosphate hydrolysis, on the other hand, was found to be regulated biologically (sensitive to occurrence of anaerobic conditions) and was insignificant in the glutaraldehyde-fixed sludge. Phosphorus release from organic phosphorus should correlate with the volatile solid (VS) digestion, which lyses the cells and frees the phosphorus covalently bonded with the organic matters. The amounts of phosphorus released per unit VS digested (deltaP/deltaVS) were therefore calculated for experiments with long periods of constant pH (to minimize interferences from dissolution/precipitation of inorganic phosphorus). The results suggested that some poly-P was hydrolyzed and released accompanying the aerobic VS digestion, but at rates far lower than those under anaerobic conditions. PMID:16274090

  9. Inorganic Plant Nutrients: Nitrogen, Phosphorus, Silicate Introduction

    E-print Network

    Jochem, Frank J.

    . The biogeochemical cycle of nitrogen is further complicated by the different forms in which nitrogen can occurLab 3: Inorganic Plant Nutrients: Nitrogen, Phosphorus, Silicate Introduction Compounds of nitrogen processes. Concentrations of nitrogen and phosphorus, on the other hand, are highly dynamic because they may

  10. PHOSPHORUS MANAGEMENT AND WATER QUALITY PROTECTION

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Phosphorus (P) is an essential nutrient for growth of crops and aquatic vegetation. Phosphorus often needs to be applied to the land for optimal crop growth. Land application of P as animal manure, biosolids (sewage sludge), and mineral fertilizer can increase the risk of P pollution of freshwater. ...

  11. The Pennsylvania Phosphorus Index, Version 2

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Increased attention on phosphorus based management due to water quality concerns has prompted federal and state governments to generate guidelines for phosphorus management on certain agricultural operations. Pennsylvania’s Nutrient Management Program (Act 38 of 2005), the Concentrated Animal Feedin...

  12. Phosphorus Moieties Make Polymers Less Flammable

    NASA Technical Reports Server (NTRS)

    Kourtides, D. A.; Mikroyannidis, J. A.

    1992-01-01

    Phosphorus incorporated into epoxies and polyamides via curing agent. According to report, use of 1-(di(2-chloroethoxyphosphinyl)methyl)-2,4- and -2,6-diaminobenzene (DCEPD) as curing agent for epoxies and polyamides makes these polymers more fire-retardant than corresponding polymers made with standard curing agents not containing phosphorus.

  13. NATIONAL PHOSPHORUS RUNOFF PROJECT: NEW YORK

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The National Phosphorus Research Project was developed to coordinate research on the interaction between agricultural management and agricultural phosphorus pollution. As part of the Project, rainfall/runoff experiments were conducted on a variety of New York soils to assess the effects of soil tes...

  14. Phosphatase Hydrolysis of Soil Organic Phosphorus Fractions

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Plant available inorganic phosphorus (Pi) is usually limited in highly weathered Ultisols. The high Fe, Al, and Mn contents in these soils enhance Pi retention and fixation. The metals are also known to form complexes with organic phosphorus (Po) compounds. Hydrolysis of Po compounds is needed for P...

  15. Phosphorus Availability Coefficients from Various Organic Sources

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The objectives of this study were to determine Phosphorus Availability Coefficients (PACs) for a variety of organic phosphorus (P) sources, and to examine the relationship between PACs measured in simulated rainfall runoff and alternative soil incubations. PAC is an important parameter in the P-Ind...

  16. Ultrafast pulse generation with black phosphorus

    E-print Network

    Li, Diao; Karvonen, Lasse; Ye, Guojun; Lipsanen, Harri; Chen, Xianhui; Sun, Zhipei

    2015-01-01

    Black phosphorus has been recently rediscovered as a new and interesting two-dimensional material due to its unique electronic and optical properties. Here, we study the linear and nonlinear optical properties of black phosphorus thin films, indicating that both linear and nonlinear optical properties are anisotropic and can be tuned by the film thickness. Then we employ the nonlinear optical property of black phosphorus for ultrafast (pulse duration down to ~786 fs in mode-locking) and large-energy (pulse energy up to >18 nJ in Q-switching) pulse generation in fiber lasers at the near-infrared telecommunication band ~1.5 {\\mu}m. Our results underscore relatively large optical nonlinearity in black phosphorus and its prospective for ultrafast pulse generation, paving the way to black phosphorus based nonlinear and ultrafast photonics applications (e.g., ultrafast all-optical switches/modulators, frequency converters etc.).

  17. Black Phosphorus Field-effect Transistors

    NASA Astrophysics Data System (ADS)

    Li, Likai; Yu, Yijun; Ye, Guojun; Ge, Qingqin; Ou, Xuedong; Wu, Hua; Feng, Donglai; Chen, Xianhui; Zhang, Yuanbo; University of Science and Technology of China Collaboration

    2014-03-01

    Black phosphorus is a layered allotropy of phosphorus that closely resembles graphite. But unlike graphene monolayer, black phosphorus is a semiconductor with a predicted band gap of ~2 eV, which reduces to ~0.3 eV in the bulk crystal. We investigate the electric property of black phosphors thin flakes with thickness down to a few nanometers. High conductance modulations up to 106 and field effect mobility up to 1000 cm2/Vs at room temperature are achieved in a Metal-Insulator-Silicon (MIS) field effect transistor structure. We further uncover the mechanism that limits the mobility in black phosphorus thin flakes through temperature-dependent electronic transport measurements. Our results provide the first basic understanding of the electronic properties of black phosphorus thin flakes, and will greatly facilitate further exploration of its future applications.

  18. Spectrophotometric determination of phosphorus acid

    SciTech Connect

    Domin, A.V.; Domina, N.G.; Zakharov, Yu.A.; Shechkov, G.T.

    1987-03-01

    A number of procedures have been proposed to determine phosphorus acid and its salts, the phosphites, in the presence of hypophosphorus acid and its salts, the hypophosphites. Among these procedures, iodometric back-titration has produced the most reliable results. In this paper, the authors propose an improved iodometric determination of phosphorus acid that enables the sensitivity to be increased by at least two orders of magnitude. The essence of this improvement is that excess iodine that did not react with phosphite ion is determined not volumetrically but spectrophotometrically. To eliminate the effect of iodine ion that is liberated when iodine reacts with phosphite ion on the optical density of the solution, a 200-fold excess of potassium iodide is added before the photometric measurement. The working iodine solution is prepared by diluting 10 m of 0.025 N iodine titrant and 50 ml of phosphate buffer, pH 6.7-7.2, to 1 liter with distilled water in a coulometric flask. To construct the calibration curve, 5, 10, 15, 20, and 25 ml, respectively of working iodine solution, and 10 ml of 2% aqueous potassium iodide are placed into five 100-ml volumetric flasks, and the solutions are made up to volume with water. After 10 min the photometric measurements are carried out at 380 nm using curvets and the reference solution is obtained by diluting 10 ml of 2% aqueous potassium iodide to 100 ml with distilled water.

  19. MEETING PHOSPHORUS REQUIREMENTS OF RUMINANTS IN AN ENVIRONMENTALLY RESPONSIBLE WAY

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Phosphorus entering lakes and streams from agricultural activity is a major stimulant to algae growth. The livestock industry, through soil application of manure, is a significant contributor of this phosphorus. One way to reduce phosphorus content of manure is to feed phosphorus to meet the anima...

  20. Bronx River bed sediments phosphorus pool and phosphorus compound identification

    NASA Astrophysics Data System (ADS)

    Wang, J.; Pant, H. K.

    2008-12-01

    Phosphorus (P) transport in the Bronx River degraded water quality, decreased oxygen levels, and resulted in bioaccumulation in sediment potentially resulting in eutrophication, algal blooms and oxygen depletion under certain temperature and pH conditions. The anthropogenic P sources are storm water runoff, raw sewage discharge, fertilizer application in lawn, golf course and New York Botanical Garden; manure from the Bronx zoo; combined sewoverflows (CSO's) from parkway and Hunts Point sewage plant; pollutants from East River. This research was conducted in the urban river system in New York City area, in order to control P source, figure out P transport temporal and spatial variations and the impact on water quality; aimed to regulate P application, sharing data with Bronx River Alliance, EPA, DEP and DEC. The sediment characteristics influence the distribution and bioavailbility of P in the Bronx River. The P sequential extraction gave the quantitative analysis of the P pool, quantifying the inorganic and organic P from the sediments. There were different P pool patterns at the 15 sites, and the substantial amount of inorganic P pool indicated that a large amount P is bioavailable. The 31P- NMR (Nuclear Magnetic Resonance Spectroscopy) technology had been used to identify P species in the 15 sites of the Bronx River, which gave a qualitative analysis on phosphorus transport in the river. The P compounds in the Bronx River bed sediments are mostly glycerophophate (GlyP), nucleoside monophosphates (NMP), polynucleotides (PolyN), and few sites showed the small amount of glucose-6-phosphate (G6P), glycerophosphoethanoamine (GPEA), phosphoenopyruvates (PEP), and inosine monophosphate (IMP). The land use spatial and temporal variations influence local water P levels, P distributions, and P compositions.

  1. The phosphorus mass balance: identifying 'hotspots' in the food system as a roadmap to phosphorus security.

    PubMed

    Cordell, Dana; Neset, Tina-Simone Schmid; Prior, Timothy

    2012-12-01

    Phosphorus is a critical element on which all life depends. Global crop production depends on fertilisers derived from phosphate rock to maintain high crop yields. Population increase, changing dietary preferences towards more meat and dairy products, and the continuing intensification of global agriculture supporting this expansion will place increasing pressure on an uncertain, but finite supply of high-quality phosphate rock. Growing concern about phosphorus scarcity and security, coupled with the environmental impact of phosphorus pollution, has encouraged an increase in research exploring how phosphorus is used and lost in the food system-from mine to field to fork. An assessment of recent phosphorus flows analyses at different geographical scales identifies the key phosphorus 'hotspots', for example within the mining, agriculture or food processing sectors, where efficiency and reuse can be substantially improved through biotechnological approaches coupled with policy changes. PMID:22503084

  2. Phosphorus limitation of coastal ecosystem processes.

    PubMed

    Sundareshwar, P V; Morris, J T; Koepfler, E K; Fornwalt, B

    2003-01-24

    Primary production in coastal wetlands is conventionally thought to be limited by nitrogen. Although the plant community in a pristine salt marsh was found to be limited primarily by nitrogen availability, the bacterial community in the soil was limited by phosphorus. Hence, in coastal wetlands, and possibly in many ecosystems, individual trophic groups may respond differently to nitrogen and phosphorus loading. Phosphorus limitation of the growth of nitrogen-transforming bacteria will affect carbon fixation, storage, and release mediated by plants, a result that has important implications for ecosystem management. PMID:12543975

  3. Tunable optical properties of multilayers black phosphorus

    E-print Network

    Low, Tony; Carvalho, A; Jiang, Yongjin; Wang, Han; Xia, Fengnian; Neto, A H Castro

    2014-01-01

    We calculated the optical conductivity tensor of multilayers black phosphorus using the Kubo formula within an effective low-energy Hamiltonian. The optical absorption spectra of multilayers black phosphorus are shown to vary sensitively with thickness, doping, and light polarization. In conjunction with experimental spectra obtained from infrared absorption spectroscopy, we discuss the role of interband coupling and disorder on the observed anisotropic absorption spectra. Multilayers black phosphorus might offer attractive alternatives to narrow gap compound semiconductors for optoelectronics across mid- to near-infrared frequencies.

  4. Phosphorus as a lunar volatile

    NASA Astrophysics Data System (ADS)

    Pasek, Matthew A.

    2015-07-01

    Phosphorus is an important minor element on the Moon. It is moderately volatile and is found as both phosphates and phosphides in lunar material. The phosphides, such as schreibersite, are common to impact breccias at all Apollo sites. The origin of this schreibersite has been proposed to be a meteoritic contaminant, or alternatively produced in situ by reduction on the lunar surface. I propose that schreibersite and other siderophilic P phases have an origin from impact volatilization of phosphates at the lunar oxygen fugacity, followed by reaction of P gases with metal to form metal phosphides. This pathway is broadly consistent with the composition and structure of metal grains, as well as the native oxygen fugacity of the lunar surface. Additionally, this pathway suggests schreibersite is widespread across the lunar surface and likely on other planetary bodies, and hence may serve as a good P source for in situ resource utilization.

  5. Innovative methods in soil phosphorus research: A review

    PubMed Central

    Kruse, Jens; Abraham, Marion; Amelung, Wulf; Baum, Christel; Bol, Roland; Kühn, Oliver; Lewandowski, Hans; Niederberger, Jörg; Oelmann, Yvonne; Rüger, Christopher; Santner, Jakob; Siebers, Meike; Siebers, Nina; Spohn, Marie; Vestergren, Johan; Vogts, Angela; Leinweber, Peter

    2015-01-01

    Phosphorus (P) is an indispensable element for all life on Earth and, during the past decade, concerns about the future of its global supply have stimulated much research on soil P and method development. This review provides an overview of advanced state-of-the-art methods currently used in soil P research. These involve bulk and spatially resolved spectroscopic and spectrometric P speciation methods (1 and 2D NMR, IR, Raman, Q-TOF MS/MS, high resolution-MS, NanoSIMS, XRF, XPS, (µ)XAS) as well as methods for assessing soil P reactions (sorption isotherms, quantum-chemical modeling, microbial biomass P, enzymes activity, DGT, 33P isotopic exchange, 18O isotope ratios). Required experimental set-ups and the potentials and limitations of individual methods present a guide for the selection of most suitable methods or combinations. PMID:26167132

  6. 40 CFR 422.20 - Applicability; description of the phosphorus consuming subcategory.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ...Applicability; description of the phosphorus consuming subcategory. 422...MANUFACTURING POINT SOURCE CATEGORY Phosphorus Consuming Subcategory § 422...Applicability; description of the phosphorus consuming subcategory....

  7. 40 CFR 422.20 - Applicability; description of the phosphorus consuming subcategory.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ...Applicability; description of the phosphorus consuming subcategory. 422...MANUFACTURING POINT SOURCE CATEGORY Phosphorus Consuming Subcategory § 422...Applicability; description of the phosphorus consuming subcategory....

  8. 40 CFR 422.20 - Applicability; description of the phosphorus consuming subcategory.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ...Applicability; description of the phosphorus consuming subcategory. 422...MANUFACTURING POINT SOURCE CATEGORY Phosphorus Consuming Subcategory § 422...Applicability; description of the phosphorus consuming subcategory....

  9. 40 CFR 422.10 - Applicability; description of the phosphorus production subcategory.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ...Applicability; description of the phosphorus production subcategory. 422...MANUFACTURING POINT SOURCE CATEGORY Phosphorus Production Subcategory § 422...Applicability; description of the phosphorus production subcategory....

  10. 40 CFR 422.10 - Applicability; description of the phosphorus production subcategory.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ...Applicability; description of the phosphorus production subcategory. 422...MANUFACTURING POINT SOURCE CATEGORY Phosphorus Production Subcategory § 422...Applicability; description of the phosphorus production subcategory....

  11. 40 CFR 422.10 - Applicability; description of the phosphorus production subcategory.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ...Applicability; description of the phosphorus production subcategory. 422...MANUFACTURING POINT SOURCE CATEGORY Phosphorus Production Subcategory § 422...Applicability; description of the phosphorus production subcategory....

  12. 40 CFR 422.20 - Applicability; description of the phosphorus consuming subcategory.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ...Applicability; description of the phosphorus consuming subcategory. 422...MANUFACTURING POINT SOURCE CATEGORY Phosphorus Consuming Subcategory § 422...Applicability; description of the phosphorus consuming subcategory....

  13. 40 CFR 422.20 - Applicability; description of the phosphorus consuming subcategory.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ...Applicability; description of the phosphorus consuming subcategory. 422...MANUFACTURING POINT SOURCE CATEGORY Phosphorus Consuming Subcategory § 422...Applicability; description of the phosphorus consuming subcategory....

  14. 40 CFR 422.10 - Applicability; description of the phosphorus production subcategory.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ...Applicability; description of the phosphorus production subcategory. 422...MANUFACTURING POINT SOURCE CATEGORY Phosphorus Production Subcategory § 422...Applicability; description of the phosphorus production subcategory....

  15. 40 CFR 422.10 - Applicability; description of the phosphorus production subcategory.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ...Applicability; description of the phosphorus production subcategory. 422...MANUFACTURING POINT SOURCE CATEGORY Phosphorus Production Subcategory § 422...Applicability; description of the phosphorus production subcategory....

  16. ENZYME DEGRADATION OF CHIRAL ORGANIC PHOSPHORUS INSECTICIDES

    EPA Science Inventory

    Chiral organic phosphorus pesticides (OPs) are expected to be biologically degraded enantioselectively by endogenous enzymes. Various chiral Ops were treated with the enzyme phosphotriesterase (PTE) obtained from partially purified extracts of Escherichia coli strain DH-5- carryi...

  17. 7 Phosphorus Modeling in Soil and Water

    E-print Network

    and Education Center, Homestead, FL C.H. Green U.S. Department of Agriculture-Agricultural Research Service 7.3 Phosphorus Movement in Surface Runoff.................................................. 175 7

  18. Anisotropic exciton Stark shift in black phosphorus

    NASA Astrophysics Data System (ADS)

    Chaves, A.; Low, Tony; Avouris, P.; ?ak?r, D.; Peeters, F. M.

    2015-04-01

    We calculate the excitonic spectrum of few-layer black phosphorus by direct diagonalization of the effective mass Hamiltonian in the presence of an applied in-plane electric field. The strong attractive interaction between electrons and holes in this system allows one to investigate the Stark effect up to very high ionizing fields, including also the excited states. Our results show that the band anisotropy in black phosphorus becomes evident in the direction-dependent field-induced polarizability of the exciton.

  19. Seasonal variation of nitrogen, phosphorus, and chlorophyll a in Lake Michigan and Green Bay, 1965

    USGS Publications Warehouse

    Allen, Herbert Ellis

    1973-01-01

    Total and dissolved phosphorus, nitrate, and chlorophyll a were measured at four stations in northern Lake Michigan (inshore Michigan, offshore Michigan, offshore Wisconsin, and inshore Wisconsin) and one station in southern Green Bay during 16 sampling periods in 1965. The nutrients were measured at depths of 2, 5, and 10 meters and chlorophyll a at 2 meters. In Green Bay total phosphorus (33.7 ppb) was about five times as high and dissolved phosphorus (7.0 ppb) more than twice as high as the averages for the four Lake Michigan stations, but nitrate nitrogen concentration (37.3 ppb) was only about onethird that in the lake. Total and dissolved phosphorus were about 50 percent higher in the inshore Michigan area than in the other three lake areas. Concentration and seasonal trends in nitrates differed relatively little among the four lake stations. Nitrate at all areas and depths sampled decreased to almost nondetectable levels during September. Chlorophyll a was 70 percent higher at the two inshore areas than at the two offshore areas in the lake and was more than four times higher in Green Bay than at any lake area.

  20. Phosphorus speciation by coupled HPLC-ICPMS: low level determination of reduced phosphorus in natural materials

    NASA Astrophysics Data System (ADS)

    Atlas, Zachary; Pasek, Matthew; Sampson, Jacqueline

    2015-04-01

    Phosphorus is a geologically important minor element in the Earth's crust commonly found as relatively insoluble apatite. This constraint causes phosphorus to be a key limiting nutrient in biologic processes. Despite this, phosphorus plays a direct role in the formation of DNA, RNA and other cellular materials. Recent works suggest that since reduced phosphorus is considerably more soluble than oxidized phosphorus that it was integrally involved in the development of life on the early Earth and may continue to play a role in biologic productivity to this day. This work examines a new method for quantification and identification of reduced phosphorus as well as applications to the speciation of organo-phosphates separated by coupled HPLC - ICP-MS. We show that reduced phosphorus species (P1+, P3+ and P5+) are cleanly separated in the HPLC and coupled with the ICPMS reaction cell, using oxygen as a reaction gas to effectively convert elemental P to P-O. Analysis at M/Z= 47 producing lower background and flatter baseline chromatography than analyses performed at M/Z = 31. Results suggest very low detection limits (0.05 ?M) for P species analyzed as P-O. Additionally we show that this technique has potential to speciate at least 5 other forms of phosphorus compounds. We verified the efficacy of method on numerous materials including leached Archean rocks, suburban retention pond waters, blood and urine samples and most samples show small but detectible levels of reduced phosphorus and or organo-phaospates. This finding in nearly all substances analyzed supports the assumption that the redox processing of phosphorus has played a significant role throughout the history of the Earth and it's presence in the present environment is nearly ubiquitous with the reduced oxidation state phosphorus compounds, phosphite and hypophosphite, potentially acting as significant constituents in the anaerobic environment.

  1. 14 CFR 33.33 - Vibration.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 14 Aeronautics and Space 1 2011-01-01 2011-01-01 false Vibration. 33.33 Section 33.33 Aeronautics... STANDARDS: AIRCRAFT ENGINES Design and Construction; Reciprocating Aircraft Engines § 33.33 Vibration. The... vibration and without imparting excessive vibration forces to the aircraft structure....

  2. 14 CFR 33.33 - Vibration.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 14 Aeronautics and Space 1 2012-01-01 2012-01-01 false Vibration. 33.33 Section 33.33 Aeronautics... STANDARDS: AIRCRAFT ENGINES Design and Construction; Reciprocating Aircraft Engines § 33.33 Vibration. The... vibration and without imparting excessive vibration forces to the aircraft structure....

  3. 14 CFR 33.33 - Vibration.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Vibration. 33.33 Section 33.33 Aeronautics... STANDARDS: AIRCRAFT ENGINES Design and Construction; Reciprocating Aircraft Engines § 33.33 Vibration. The... vibration and without imparting excessive vibration forces to the aircraft structure....

  4. 14 CFR 33.33 - Vibration.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 14 Aeronautics and Space 1 2013-01-01 2013-01-01 false Vibration. 33.33 Section 33.33 Aeronautics... STANDARDS: AIRCRAFT ENGINES Design and Construction; Reciprocating Aircraft Engines § 33.33 Vibration. The... vibration and without imparting excessive vibration forces to the aircraft structure....

  5. 14 CFR 33.33 - Vibration.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 14 Aeronautics and Space 1 2014-01-01 2014-01-01 false Vibration. 33.33 Section 33.33 Aeronautics... STANDARDS: AIRCRAFT ENGINES Design and Construction; Reciprocating Aircraft Engines § 33.33 Vibration. The... vibration and without imparting excessive vibration forces to the aircraft structure....

  6. 14 CFR 33.33 - Vibration.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ...2012-01-01 2012-01-01 false Vibration. 33.33 Section 33.33 Aeronautics...Reciprocating Aircraft Engines § 33.33 Vibration. The engine must be designed...in any of the engine parts because of vibration and without imparting excessive...

  7. 14 CFR 33.33 - Vibration.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ...2013-01-01 2013-01-01 false Vibration. 33.33 Section 33.33 Aeronautics...Reciprocating Aircraft Engines § 33.33 Vibration. The engine must be designed...in any of the engine parts because of vibration and without imparting excessive...

  8. 14 CFR 33.33 - Vibration.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ...2014-01-01 2014-01-01 false Vibration. 33.33 Section 33.33 Aeronautics...Reciprocating Aircraft Engines § 33.33 Vibration. The engine must be designed...in any of the engine parts because of vibration and without imparting excessive...

  9. 14 CFR 33.33 - Vibration.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ...2010-01-01 2010-01-01 false Vibration. 33.33 Section 33.33 Aeronautics...Reciprocating Aircraft Engines § 33.33 Vibration. The engine must be designed...in any of the engine parts because of vibration and without imparting excessive...

  10. Evaluation of Phosphorus Source Coefficients as Predictors of Runoff Phosphorus Concentrations

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The objectives of this study were to determine Phosphorus Source Coefficients (PSC) for organic phosphorus (P) sources, and to examine the relationship between PSCs and P concentrations measured in simulated rainfall runoff. The PSC is an important parameter in the P Site Index (PSI). An incubatio...

  11. Production of Low-Phosphorus Molten Iron from High-Phosphorus Oolitic Hematite Using Biomass Char

    NASA Astrophysics Data System (ADS)

    Tang, Huiqing; Qi, Tengfei; Qin, Yanqi

    2015-09-01

    In this study, an energy-saving and environmentally friendly method to produce low-phosphorus molten iron from high-phosphorus oolitic hematite was experimentally investigated and theoretically analyzed. The results indicate that biomass char is a suitable reducing agent for the proposed method. In the direct reduction stage, the ore-char briquette reached a metallization degree of 80-82% and a residual carbon content of 0.1-0.3 mass%. Under the optimized condition, phosphorus remained in the gangue as calcium phosphate. In the melting separation stage, phosphorus content ([%P]) in molten iron could be controlled by introducing a Na2CO3 additive, and the phosphorus behavior could be predicted using ion molecular coexistence theory. Molten iron with [%P] less than 0.3 mass% was obtained from the metallic briquettes with the aforementioned quality by introducing 2-4% Na2CO3 and the iron recovery rate was 75-78%.

  12. The renaissance of black phosphorus

    PubMed Central

    Ling, Xi; Wang, Han; Huang, Shengxi; Xia, Fengnian; Dresselhaus, Mildred S.

    2015-01-01

    One hundred years after its first successful synthesis in the bulk form in 1914, black phosphorus (black P) was recently rediscovered from the perspective of a 2D layered material, attracting tremendous interest from condensed matter physicists, chemists, semiconductor device engineers, and material scientists. Similar to graphite and transition metal dichalcogenides (TMDs), black P has a layered structure but with a unique puckered single-layer geometry. Because the direct electronic band gap of thin film black P can be varied from 0.3 eV to around 2 eV, depending on its film thickness, and because of its high carrier mobility and anisotropic in-plane properties, black P is promising for novel applications in nanoelectronics and nanophotonics different from graphene and TMDs. Black P as a nanomaterial has already attracted much attention from researchers within the past year. Here, we offer our opinions on this emerging material with the goal of motivating and inspiring fellow researchers in the 2D materials community and the broad readership of PNAS to discuss and contribute to this exciting new field. We also give our perspectives on future 2D and thin film black P research directions, aiming to assist researchers coming from a variety of disciplines who are desirous of working in this exciting research field. PMID:25820173

  13. Nanoscopy Reveals Metallic Black Phosphorus

    E-print Network

    Abate, Yohannes; Zhen, Li; Cronin, Stephen B; Wang, Han; Babicheva, Viktoriia; Javani, Mohammad H; Stockman, Mark I

    2015-01-01

    Layered and two-dimensional (2D) materials such as graphene, boron nitride, transition metal dichalcogenides(TMDCs), and black phosphorus (BP) have intriguing fundamental physical properties and bear promise of numerous important applications in electronics and optics. Of them, BP is a novel 2D material that has been theoretically predicted to acquire plasmonic behavior for frequencies below ~0.4 eV when highly doped. The electronic properties of BP are unique due to an anisotropic structure, which could strongly influence collective electronic excitations. Advantages of BP as a material for nanoelectronics and nanooptics are due to the fact that, in contrast to metals, the free carrier density in it can be dynamically controlled by electrostatic gating, which has been demonstrated by its use in field-effect transistors. Despite all the interest that BP attracts, near-field and plasmonic properties of BP have not yet been investigated experimentally. Here we report the first observation of nanoscopic near-fie...

  14. The renaissance of black phosphorus.

    PubMed

    Ling, Xi; Wang, Han; Huang, Shengxi; Xia, Fengnian; Dresselhaus, Mildred S

    2015-04-14

    One hundred years after its first successful synthesis in the bulk form in 1914, black phosphorus (black P) was recently rediscovered from the perspective of a 2D layered material, attracting tremendous interest from condensed matter physicists, chemists, semiconductor device engineers, and material scientists. Similar to graphite and transition metal dichalcogenides (TMDs), black P has a layered structure but with a unique puckered single-layer geometry. Because the direct electronic band gap of thin film black P can be varied from 0.3 eV to around 2 eV, depending on its film thickness, and because of its high carrier mobility and anisotropic in-plane properties, black P is promising for novel applications in nanoelectronics and nanophotonics different from graphene and TMDs. Black P as a nanomaterial has already attracted much attention from researchers within the past year. Here, we offer our opinions on this emerging material with the goal of motivating and inspiring fellow researchers in the 2D materials community and the broad readership of PNAS to discuss and contribute to this exciting new field. We also give our perspectives on future 2D and thin film black P research directions, aiming to assist researchers coming from a variety of disciplines who are desirous of working in this exciting research field. PMID:25820173

  15. Characteristics and biodiversity of endophytic phosphorus- and potassium-solubilizing bacteria in Moso Bamboo (Phyllostachys edulis).

    PubMed

    Yuan, Zong-Sheng; Liu, Fang; Zhang, Guo-Fang

    2015-12-01

    Endophytic phosphorus- and potassium-solubilizing bacteria were screened from the root, rhizome, stem, and leaves of Moso Bamboo, and their diversity was analyzed using their 16S rDNA sequences. Twenty endophytic phosphorus and potassium-solubilizing bacteria were screened from 82 bamboo plants, among which the CT-B09-2, WYS-A01-1 and JL-B06 had higher activities in decomposing organophosphates. The three species showed a decomposition diameter/colony diameter (D/d) of 5.05, 4.19 and 2.95, respectively, and a solubilizing activity of 81.77 mg/L, 77.85 mg/L and 63.69 mg/L, respectively. JL-B06, WYS-A01-1 and CT-B09-2 had higher activities in decomposing inorganic phosphorus, with a decomposition diameter/colony diameter (D/d) of 2.34, 2.12 and 1.82, respectively, and a solubilizing activity of 30.58 mg/L, 38.89 mg/L and 48.35 mg/L, respectively. CT-B21, WYS-A03-1 and JL-B06 had higher activities in decomposing potassium, with a decomposition diameter/colony diameter (D/d) of 3.37, 4.84 and 4.33, respectively, and a solubilizing activity of 2.81 mg/L, 2.54 mg/L and 2.46 mg/L, respectively. The 16S rDNA sequence analysis showed that the 20 phosphorus- and potassium-solubilizing bacteria belong to 14 species from 10 genera, and mainly consist of Alcaligenes spp., Enterobacter spp. and Bacillus spp. Our results demonstrate the abundant diversity of endophytic phosphorus- and potassiumsolubilizing bacteria in Moso Bamboo. PMID:26616376

  16. PRIMARY RESEARCH PAPER Phosphorus and carbohydrate limitation of fecal coliform

    E-print Network

    Mallin, Michael

    PRIMARY RESEARCH PAPER Phosphorus and carbohydrate limitation of fecal coliform and fecal phosphorus, sediment carbohydrate, and environmental factors were made and relationships with bacteria or carbohydrate. Experimental results suggested that sediment-associ- ated fecal bacteria were more frequently

  17. PHOSPHORUS REMOVAL IN LOWER GREAT LAKES MUNICIPAL TREATMENT PLANTS

    EPA Science Inventory

    This report discusses a survey of phosphorus treatment approaches and accomplishments for all lower Great Lakes basin plants with flows greater than 1 mgd; field operation monitoring studies to evaluate the performance of four municipal treatment plants practicing phosphorus remo...

  18. Phosphorus: Tips for People with Chronic Kidney Disease (CKD)

    MedlinePLUS

    ... in foods rich in protein, such as meat, poultry, fish, nuts, beans, and dairy products. Phosphorus is ... iced tea Foods Higher in Phosphorus l Meat, poultry, fish l Dairy foods l Beans, lentils, nuts ...

  19. Doping and Raman Characterization of Boron and Phosphorus Atoms in

    E-print Network

    Wang, Zhong L.

    Doping and Raman Characterization of Boron and Phosphorus Atoms in Germanium Nanowires Naoki Fukata. The chemical bonding states and electrical activity of boron (B) and phosphorus (P) atoms in germanium

  20. Phosphorus Spin Coherence Times in Silicon at Very Low Temperatures

    E-print Network

    L. K. Alexander; N. Suwuntanasarn; W. D. Hutchison

    2010-09-22

    Phosphorus donor spin coherence in isotopically pure 28 silicon is measured at very low temperatures using pulsed electron spin resonance. The isolated spin T2 varies unexpectedly with phosphorus concentration

  1. Zooplankton and the total phosphorus chlorophyll a relationship: hierarchical Bayesian

    E-print Network

    Notre Dame, University of

    Zooplankton and the total phosphorus ­ chlorophyll a relationship: hierarchical Bayesian analysis: Zooplankton grazing is important in resolving residual variation around the total phosphorus ­ chlorophyll found consistent effects of total zooplankton biomass, but not zooplankton length, on chlorophyll a

  2. Phosphorus--Too Much and Plants May Suffer 

    E-print Network

    Provin, Tony; Pitt, John L.

    2008-05-09

    The buildup of phosphorus in lawns, gardens, pastures and croplands can cause plants to grow poorly and even die. This publication explains how to identify problems caused by excessive phosphorus and how to correct those problems....

  3. Response of Sugarcane in a Red Ultisol to Phosphorus Rates, Phosphorus Sources, and Filter Cake.

    PubMed

    Caione, Gustavo; Prado, Renato de Mello; Campos, Cid Naudi Silva; Rosatto Moda, Leandro; de Lima Vasconcelos, Ricardo; Pizauro Júnior, João Martins

    2015-01-01

    We evaluated the effect of phosphorus application rates from various sources and in the presence or absence of filter cake on soil phosphorus, plant phosphorus, changes in acid phosphatase activity, and sugarcane productivity grown in Eutrophic Red Ultisol. Three P sources were used (triple superphosphate, Araxa rock phosphate, and Bayovar rock phosphate) and four application rates (0, 90, 180, and 360 kg ha(-1) of P2O5) in the presence or absence of filter cake (7.5 t ha(-1), dry basis). The soil P, the accumulated plant P, the leaf acid phosphatase activity and straw, the stalk productivity, the concentration of soluble solids in the juice (Brix), the juice sucrose content (Pol), and the purity were the parameters evaluated. We found that P applications increased levels of soil, leaf, and juice phosphorus and led to higher phosphorus accumulation and greater stalk and straw productivity. These levels were highest in the presence of filter cake. Acid phosphatase activity decreased with increasing plant phosphorus concentration. Phosphate fertilization did not show effect on sugarcane technological quality. We concluded that P application, regardless of source, improved phosphorus nutrition and increased productivity in sugarcane and, when associated with filter cake, reduced the need for mineral fertilizer. PMID:26078993

  4. Response of Sugarcane in a Red Ultisol to Phosphorus Rates, Phosphorus Sources, and Filter Cake

    PubMed Central

    Prado, Renato de Mello; Campos, Cid Naudi Silva; Rosatto Moda, Leandro; de Lima Vasconcelos, Ricardo; Pizauro Júnior, João Martins

    2015-01-01

    We evaluated the effect of phosphorus application rates from various sources and in the presence or absence of filter cake on soil phosphorus, plant phosphorus, changes in acid phosphatase activity, and sugarcane productivity grown in Eutrophic Red Ultisol. Three P sources were used (triple superphosphate, Araxa rock phosphate, and Bayovar rock phosphate) and four application rates (0, 90, 180, and 360?kg?ha?1 of P2O5) in the presence or absence of filter cake (7.5?t?ha?1, dry basis). The soil P, the accumulated plant P, the leaf acid phosphatase activity and straw, the stalk productivity, the concentration of soluble solids in the juice (Brix), the juice sucrose content (Pol), and the purity were the parameters evaluated. We found that P applications increased levels of soil, leaf, and juice phosphorus and led to higher phosphorus accumulation and greater stalk and straw productivity. These levels were highest in the presence of filter cake. Acid phosphatase activity decreased with increasing plant phosphorus concentration. Phosphate fertilization did not show effect on sugarcane technological quality. We concluded that P application, regardless of source, improved phosphorus nutrition and increased productivity in sugarcane and, when associated with filter cake, reduced the need for mineral fertilizer. PMID:26078993

  5. Sargasso Sea phosphorus biogeochemistry: an important role for dissolved organic phosphorus (DOP)

    NASA Astrophysics Data System (ADS)

    Lomas, M. W.; Burke, A. L.; Lomas, D. A.; Bell, D. W.; Shen, C.; Dyhrman, S. T.; Ammerman, J. W.

    2010-02-01

    Inorganic phosphorus (SRP) concentrations in the subtropical North Atlantic are some of the lowest in the global ocean and have been hypothesized to constrain primary production. Based upon data from several transect cruises in this region, it has been hypothesized that dissolved organic phosphorus (DOP) supports a significant fraction of primary production in the subtropical North Atlantic. In this study, a time-series of phosphorus biogeochemistry is presented for the Bermuda Atlantic Time-series Study site, including rates of phosphorus export. Most parameters have a seasonal pattern, although year-over-year variability in the seasonal pattern is substantial, likely due to differences in external forcing. Suspended particulate phosphorus exhibits a seasonal maximum during the spring bloom, despite the absence of a seasonal peak in SRP. However, DOP concentrations are at an annual maximum prior to the winter/spring bloom and decline over the course of the spring bloom while whole community alkaline phosphatase activities are highest. As a result of DOP bioavailability, the growth of particles during the spring bloom occurs in Redfield proportions, though particles exported from the euphotic zone show rapid and significant remineralization of phosphorus within the first 50 m below the euphotic zone. Based upon DOP data from transect cruises in this region, the southward cross gyral flux of DOP is estimated to support ~25% of annual primary production and ~100% of phosphorus export. These estimates are consistent with other research in the subtropical North Atlantic and reinforce the hypothesis that while the subtropics may be phosphorus stressed (a physiological response to low inorganic phosphorus), utilization of the DOP pool allows production and accumulation of microbial biomass at Redfield proportions.

  6. Sargasso Sea phosphorus biogeochemistry: an important role for dissolved organic phosphorus (DOP)

    NASA Astrophysics Data System (ADS)

    Lomas, M. W.; Burke, A. L.; Lomas, D. A.; Bell, D. W.; Shen, C.; Dyhrman, S. T.; Ammerman, J. W.

    2009-10-01

    Inorganic phosphorus (SRP) concentrations in the subtropical North Atlantic are some of the lowest in the global ocean and have been hypothesized to constrain primary production. Based upon data from several transect cruises in this region, it has been hypothesized that dissolved organic phosphorus (DOP) supports a significant fraction of primary production. In this study, a time-series of phosphorus biogeochemistry is presented for the Bermuda Atlantic Time-series Study site, including rates of phosphorus export. Most parameters have a seasonal pattern, although year-over-year variability in the seasonal pattern is substantial, likely due to differences in external forcing. Suspended particulate phosphorus exhibits a seasonal maximum during the spring bloom, despite the absence of a seasonal peak in SRP. However, DOP concentrations are at an annual maximum prior to the winter/spring bloom and decline over the course of the spring bloom while whole community alkaline phosphatase activities are highest. As a result of DOP bioavailability, the growth of particles during the spring bloom occurs in Redfield proportions, though particles exported from the euphotic zone show rapid and significant remineralization of phosphorus within the first 50 m below the euphotic zone. Based upon DOP data from transect cruises in this region, the southward cross gyral flux of DOP is estimated to support ~32% of annual primary production and ~100% of phosphorus export. These estimates are consistent with other research in the subtropical North Atlantic and reinforce the hypothesis that while the subtropics may be phosphorus stressed (a physiological response to low inorganic phosphorus), utilization of the DOP pool allows production and accumulation of microbial biomass at Redfield proportions.

  7. Electric field effect in ultrathin black phosphorus

    SciTech Connect

    Koenig, Steven P.; Schmidt, Hennrik; Doganov, Rostislav A.; Castro Neto, A. H.; Özyilmaz, Barbaros

    2014-03-10

    Black phosphorus exhibits a layered structure similar to graphene, allowing mechanical exfoliation of ultrathin single crystals. Here, we demonstrate few-layer black phosphorus field effect devices on Si/SiO{sub 2} and measure charge carrier mobility in a four-probe configuration as well as drain current modulation in a two-point configuration. We find room-temperature mobilities of up to 300 cm{sup 2}/Vs and drain current modulation of over 10{sup 3}. At low temperatures, the on-off ratio exceeds 10{sup 5}, and the device exhibits both electron and hole conduction. Using atomic force microscopy, we observe significant surface roughening of thin black phosphorus crystals over the course of 1 h after exfoliation.

  8. Flammability of Epoxy Resins Containing Phosphorus

    NASA Technical Reports Server (NTRS)

    Hergenrother, P. M.; Thompson, C. M.; Smith, J. G.; Connell, J. W.; Hinkley, J. A.

    2005-01-01

    As part of a program to develop fire-resistant exterior composite structures for future subsonic commercial and general aviation aircraft, flame-retardant epoxy resins are under investigation. Epoxies and their curing agents (aromatic diamines) containing phosphorus were synthesized and used to prepare epoxy formulations. Phosphorus was incorporated within the backbone of the epoxy resin and not used as an additive. The resulting cured neat epoxy formulations were characterized by thermogravimetric analysis, propane torch test, elemental analysis, microscale combustion calorimetry, and fire calorimetry. Several formulations showed excellent flame retardation with phosphorous contents as low as 1.5% by weight. The fracture toughness and compressive strength of several cured formulations showed no detrimental effect due to phosphorus content. The chemistry and properties of these new epoxy formulations are discussed.

  9. Electric field effect in ultrathin black phosphorus

    NASA Astrophysics Data System (ADS)

    Koenig, Steven P.; Doganov, Rostislav A.; Schmidt, Hennrik; Castro Neto, A. H.; Özyilmaz, Barbaros

    2014-03-01

    Black phosphorus exhibits a layered structure similar to graphene, allowing mechanical exfoliation of ultrathin single crystals. Here, we demonstrate few-layer black phosphorus field effect devices on Si/SiO2 and measure charge carrier mobility in a four-probe configuration as well as drain current modulation in a two-point configuration. We find room-temperature mobilities of up to 300 cm2/Vs and drain current modulation of over 103. At low temperatures, the on-off ratio exceeds 105, and the device exhibits both electron and hole conduction. Using atomic force microscopy, we observe significant surface roughening of thin black phosphorus crystals over the course of 1 h after exfoliation.

  10. The microscope structures of amorphous phosphorus

    NASA Astrophysics Data System (ADS)

    Olego, D. J.; Baumann, J. A.; Schachter, R.

    1985-03-01

    The microscopic structures of thin films of amorphous phosphorus have been investigated by Raman scattering. The thin films were deposited by vacuum evaporation at substrate temperatures T s between 300 and 510K. The Raman spectra of the films were compared with vibrational spectra of different allotropes of phosphorus: orthohombic black P, bulk amorphous red P and Hittorf's P. The structure of the films with T s ? 300K is built up of double layers similar to those of orthorhombic black P. For T s?510K the thin films have a structure similar to bulk amorphous red P based on the pentagonal tubes of Hittorf's P. A continuous transformation from one structure to the other is indicated by the Raman spectra of the films at intermediate T s. The Raman measurements support early determinations of the structures of amorphous phosphorus inferred from radial distribution functions.

  11. Observations of interstellar chlorine and phosphorus

    NASA Technical Reports Server (NTRS)

    Jura, M.; York, D. G.

    1978-01-01

    Copernicus observations of interstellar Cl I, Cl II, and P II UV lines toward 10 stars are reported. Column densities are estimated for each species, and upper limits are computed for HCl column densities. Derivation of the gas-phase abundances of chlorine and phosphorus indicates that the averages of both the chlorine and the phosphorus logarithmic abundances relative to hydrogen are between 5.0 and 5.1. It is suggested that interstellar chlorine may be depleted by about a factor of 3 relative to the solar abundance and that interstellar phosphorus is depleted by a factor of 2 to 3. The results are shown to support the prediction that chlorine is ionized in regions containing primarily atomic oxygen and is neutral in regions where there is a significant amount of molecular hydrogen. The photoionization rate of neutral chlorine toward 15 Mon is estimated, and it is concluded that most chlorine is contained within the gas phase.

  12. Selective myelosuppression following yellow phosphorus ingestion.

    PubMed

    Basheer, Aneesh; Mookkappan, Sudhagar; Padhi, Somanath; Iqbal, Nayyar

    2015-01-01

    Toxicity from accidental and intentional ingestion of yellow phosphorus, ubiquitously present in fireworks and rodenticides, has recently become more frequent. Gastrointestinal, renal, neurologic, and cardiovascular manifestations are common, with mortality of 23 per cent to 73 per cent. Reports of haematological abnormalities are rare. We report only the second case of severe neutropenia secondary to selective myelosuppression in a 14-year-old girl following intentional ingestion of yellow phosphorus. Leucocyte counts recovered spontaneously without further complications. Our case indicates that, besides hepatic and renal function monitoring, physicians should meticulously monitor blood counts in such cases for early detection of marrow suppression. Further studies are required to elucidate the complex mechanisms and significance of this unusual toxicity of yellow phosphorus. PMID:25848404

  13. 40 CFR 721.2752 - Epoxy resin containing phosphorus (generic).

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 31 2011-07-01 2011-07-01 false Epoxy resin containing phosphorus... Specific Chemical Substances § 721.2752 Epoxy resin containing phosphorus (generic). (a) Chemical substance... epoxy resin containing phosphorus (PMN P-00-912) is subject to reporting under this section for...

  14. 21 CFR 862.1580 - Phosphorus (inorganic) test system.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Phosphorus (inorganic) test system. 862.1580... (CONTINUED) MEDICAL DEVICES CLINICAL CHEMISTRY AND CLINICAL TOXICOLOGY DEVICES Clinical Chemistry Test Systems § 862.1580 Phosphorus (inorganic) test system. (a) Identification. A phosphorus (inorganic)...

  15. 21 CFR 862.1580 - Phosphorus (inorganic) test system.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Phosphorus (inorganic) test system. 862.1580... (CONTINUED) MEDICAL DEVICES CLINICAL CHEMISTRY AND CLINICAL TOXICOLOGY DEVICES Clinical Chemistry Test Systems § 862.1580 Phosphorus (inorganic) test system. (a) Identification. A phosphorus (inorganic)...

  16. 21 CFR 862.1580 - Phosphorus (inorganic) test system.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Phosphorus (inorganic) test system. 862.1580... (CONTINUED) MEDICAL DEVICES CLINICAL CHEMISTRY AND CLINICAL TOXICOLOGY DEVICES Clinical Chemistry Test Systems § 862.1580 Phosphorus (inorganic) test system. (a) Identification. A phosphorus (inorganic)...

  17. 21 CFR 862.1580 - Phosphorus (inorganic) test system.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Phosphorus (inorganic) test system. 862.1580... (CONTINUED) MEDICAL DEVICES CLINICAL CHEMISTRY AND CLINICAL TOXICOLOGY DEVICES Clinical Chemistry Test Systems § 862.1580 Phosphorus (inorganic) test system. (a) Identification. A phosphorus (inorganic)...

  18. 46 CFR 151.50-50 - Elemental phosphorus in water.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 46 Shipping 5 2012-10-01 2012-10-01 false Elemental phosphorus in water. 151.50-50 Section 151.50... phosphorus in water. (a) Tanks shall be designed and tested for a head equivalent to the design lading of phosphorus and its water blanket extended to 8 feet above the tank top. In addition, tank design...

  19. 46 CFR 151.50-50 - Elemental phosphorus in water.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 46 Shipping 5 2010-10-01 2010-10-01 false Elemental phosphorus in water. 151.50-50 Section 151.50... phosphorus in water. (a) Tanks shall be designed and tested for a head equivalent to the design lading of phosphorus and its water blanket extended to 8 feet above the tank top. In addition, tank design...

  20. Comparison of arsenic and phosphorus diffusion behavior in silicongermanium alloys

    E-print Network

    Comparison of arsenic and phosphorus diffusion behavior in silicon­germanium alloys S. Eguchia of ion-implanted arsenic and phosphorus in relaxed Si0.8Ge0.2 has been investigated. Under equilibrium is roughly seven for arsenic, and roughly two for phosphorus. Under transient diffusion conditions

  1. Soil phosphorus dynamics under sprinkler and furrow irrigation

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Furrow irrigation detaches and transports soil particles and subsequently nutrients such as phosphorus. To reduce the risk of erosion and offsite phosphorus movement, producers can convert from furrow to sprinkler irrigation. We completed research on soil phosphorus dynamics in furrow versus sprin...

  2. 46 CFR 151.50-50 - Elemental phosphorus in water.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 46 Shipping 5 2013-10-01 2013-10-01 false Elemental phosphorus in water. 151.50-50 Section 151.50... phosphorus in water. (a) Tanks shall be designed and tested for a head equivalent to the design lading of phosphorus and its water blanket extended to 8 feet above the tank top. In addition, tank design...

  3. 46 CFR 151.50-50 - Elemental phosphorus in water.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 46 Shipping 5 2014-10-01 2014-10-01 false Elemental phosphorus in water. 151.50-50 Section 151.50... phosphorus in water. (a) Tanks shall be designed and tested for a head equivalent to the design lading of phosphorus and its water blanket extended to 8 feet above the tank top. In addition, tank design...

  4. 46 CFR 151.50-50 - Elemental phosphorus in water.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 46 Shipping 5 2011-10-01 2011-10-01 false Elemental phosphorus in water. 151.50-50 Section 151.50... phosphorus in water. (a) Tanks shall be designed and tested for a head equivalent to the design lading of phosphorus and its water blanket extended to 8 feet above the tank top. In addition, tank design...

  5. Supplemental on-line material for Semiconducting layered blue phosphorus

    E-print Network

    Tománek, David

    en- ergy in black phosphorus is 20 meV/atom according to PBE and 100 meV/atom according to LDA the LDA value of 38 meV/atom. S2. BULK BAND STRUCTURE OF BLACK AND BLUE PHOSPHORUS The calculated bulk band structures of black and blue phosphorus are presented in Fig. S1. There is a strong band

  6. Polarized photocurrent response in black phosphorus field-effect transistors

    E-print Network

    Wikswo, John

    Polarized photocurrent response in black phosphorus field-effect transistors Tu Hong,a Bhim-layer black phosphorus (BP) crystals down to a few nanometers. In particular, we explore the anisotropic, a new class of 2D layered material, few-layer black phosphorus (BP) or phosphorene, has shown excellent

  7. PHOSPHORUS: A Task-Based Agent Matchmaker Yolanda Gil

    E-print Network

    Southern California, University of

    PHOSPHORUS: A Task-Based Agent Matchmaker Yolanda Gil Information Sciences Institute University, U.S.A. surya@isi.edu ABSTRACT PHOSPHORUS is an agent matchmaking service that exploits do- main of accomplishing, as well as requests to locate agents with a required capability. PHOSPHORUS supports match- ing

  8. 49 CFR 173.188 - White or yellow phosphorus.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ...2012-10-01 2012-10-01 false White or yellow phosphorus. 173.188 Section 173.188 Transportation...Class 1 and Class 7 § 173.188 White or yellow phosphorus. Phosphorus, white or yellow, when offered for...

  9. PHOSPHORUS CONTENT OF WATERS ALONG THE WEST COAST OF FLORIDA

    E-print Network

    PHOSPHORUS CONTENT OF WATERS ALONG THE WEST COAST OF FLORIDA Marine Biological Laboratory WOODS PHOSPHORUS CONTENT OF WATERS ALONG THF WEST COAST OF FLORIDA Herbert Wo Graham, Fishery Biologist, John Mo, 195U #12;ABSTRACT The distribution of inorganic and total phosphorus in the waters along the west

  10. Phosphorus diffusion in isoconcentration backgrounds under inert conditions in silicon

    E-print Network

    Florida, University of

    Phosphorus diffusion in isoconcentration backgrounds under inert conditions in silicon Jay P. John (Received 29 May 1992; accepted for publication 31 December 1992) The diffusivity of phosphorus in isoconcentration backgrounds under inert conditions in silicon is investigated. Phosphorus is implanted at low dose

  11. 40 CFR 721.2752 - Epoxy resin containing phosphorus (generic).

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Epoxy resin containing phosphorus... Specific Chemical Substances § 721.2752 Epoxy resin containing phosphorus (generic). (a) Chemical substance... epoxy resin containing phosphorus (PMN P-00-912) is subject to reporting under this section for...

  12. Incommensurate Structure of Phosphorus Phase IV

    SciTech Connect

    Fujihisa, Hiroshi; Gotoh, Yoshito; Yamawaki, Hiroshi; Sakashita, Mami; Takeya, Satoshi; Honda, Kazumasa; Akahama, Yuichi; Kawamura, Haruki; Ohishi, Yasuo

    2007-04-27

    There are six known phases for phosphorus at room temperature under high pressure. Only the structure of phase IV, which exists from 107 GPa to 137 GPa, remains unsolved. We performed a powder x-ray diffraction experiment and a Rietveld analysis and successfully determined its structure to be an incommensurately modulated structure by only 1 site of atomic position. High-pressure phases of halogens and chalcogens have previously been shown to have a similar modulated structure; however, phosphorus phase IV is different from them and was shown to be the third case.

  13. New phosphorus-containing bisimide resins

    NASA Technical Reports Server (NTRS)

    Varma, I. K.; Fohlen, G. M.; Hsu, M.-T.; Parker, J. A.

    1984-01-01

    Phosphorus-based flame retardants have been effectively used in a wide variety of polymeric materials. Such additives, however, may either influence the decomposition reaction in polymers or lack durability due to a tendency to be leached out by solvents. Attention is given to the synthesis, characterization, thermal stability and degradation mechanisms of bisimide resins, and an evaluation is conducted of the flammability and mechanical properties of graphite cloth-reinforced laminates fabricated from one of the six phosphorus-containing bisimide resins considered.

  14. Focused phosphorus ion beam implantation into silicon

    NASA Astrophysics Data System (ADS)

    Madokoro, Y.; Shukuri, S.; Umemura, K.; Tamura, M.

    1989-03-01

    Phosphorus implantation into (100) silicon using a 32-keV focused ion beam is investigated from the standpoints of electrical properties and damage to the implanted layers. Phosphorus ions are extracted from the Pt?P?Sb alloy liguid-metal-ion source. Electrical properties are measured by isochronal annealing with Hall measurements and radiation damage is evaluated using a transmission electron microscope. Compared with the conventional implantation method, focused ion beam implantation causes heavier radiation damage and forms amorphous layers at a dose of 2 × 10 14 cm -2 due to high current density.

  15. Phosphorus index as a phosphorus awareness tool: documented phosphorus use reduction in New York state.

    PubMed

    Ketterings, Quirine M; Czymmek, Karl J

    2012-01-01

    In 1999, New York introduced its concentrated animal feeding operation (CAFO) permit followed, in 2001, by release of the New York phosphorus index (NY-PI) and establishment of a statewide on-farm research partnership. State policy requires that the Natural Resources Conservation Service's 590 nutrient management standard, and therefore the NY-PI, be implemented on all CAFO farms as well as animal feeding operations (AFOs) receiving state or federal cost share funds for manure storage and other related practices. Since the introduction of the NY-PI, P fertilizer sales (farm use) declined from 14,470 Mg in 2001 (8.6 kg P ha) to 7,376 Mg in 2009 (5.0 kg P ha). Cost of fertilizer was not a significant covariate for the reduction in P use over time. Certified nutrient management planners were surveyed in 2011 to evaluate their perceptions of drivers for changes in P use. In addition, whole farm P balances were recorded for 54 New York dairy farms. The survey data illustrate key ingredients for success: (i) statewide awareness of environmental challenges through both regulations and extension programming; (ii) science-based, user-friendly tools that allow for farm-specific responses to the challenges; (iii) risk assessment of management alternatives through on-farm research; (iv) enforcement of regulations; and (v) existence of economically feasible alternatives. Whole farm balances showed a reduction in P surplus of 44%, averaged across farms, whereas milk production increased, further illustrating the willingness and economic potential to make changes that improve production efficiency and reduce risk of nutrient loss to the environment. PMID:23128734

  16. Phosphorus vacancy cluster model for phosphorus diffusion gettering of metals in Si

    SciTech Connect

    Chen, Renyu; Trzynadlowski, Bart; Dunham, Scott T.

    2014-02-07

    In this work, we develop models for the gettering of metals in silicon by high phosphorus concentration. We first performed ab initio calculations to determine favorable configurations of complexes involving phosphorus and transition metals (Fe, Cu, Cr, Ni, Ti, Mo, and W). Our ab initio calculations found that the P{sub 4}V cluster, a vacancy surrounded by 4 nearest-neighbor phosphorus atoms, which is the most favorable inactive P species in heavily doped Si, strongly binds metals such as Cu, Cr, Ni, and Fe. Based on the calculated binding energies, we build continuum models to describe the P deactivation and Fe gettering processes with model parameters calibrated against experimental data. In contrast to previous models assuming metal-P{sub 1}V or metal-P{sub 2}V as the gettered species, the binding of metals to P{sub 4}V satisfactorily explains the experimentally observed strong gettering behavior at high phosphorus concentrations.

  17. Investigation into phosphorus removal by iron ochre for the potential treatment of aquatic phosphorus pollution 

    E-print Network

    Carr, Stephen Thomas David

    2012-11-29

    Phosphorus (P) pollution of waterbodies is a global issue with detrimental environmental, social and economic impacts. Low-cost and sustainable P removal technologies are therefore required to tackle P pollution, whilst ...

  18. 14 CFR 33.33 - Vibration.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION AIRCRAFT AIRWORTHINESS STANDARDS: AIRCRAFT ENGINES Design and Construction; Reciprocating Aircraft Engines § 33.33 Vibration. The engine must be designed and...

  19. Temporal dynamics of available and microbial phosphorus and organic phosphorus mineralization in a grassland soil

    NASA Astrophysics Data System (ADS)

    Liebisch, Frank; Keller, Fabrizio; Frossard, Emmanuel; Huguenin-Elie, Olivier; Oberson, Astrid; Bünemann, Else

    2010-05-01

    Turnover of phosphorus (P) through the microbial biomass and P mineralization have been reported as two main biological factors controlling P availability in soils. This is particularly true for grassland soils where organic matter is accumulated in the topsoil and microbial activity is high. The amounts of plant available inorganic P and microbial P can fluctuate over the season, but their interaction and responses to changes in environmental conditions, fertilization and cutting are not yet well understood. Also, gross P mineralization has not yet been measured in grassland soils. We studied P mineralization and immobilization in a species rich grassland managed at low intensity (with three harvests per season) under different P inputs. The trial was established in 1992 in Watt (Switzerland). Three different P input treatments were selected: no P (NK), mineral P (NPK) and organic P (NPKorg) fertilization, with 17 kg P ha-1yr-1 applied as superphosphate and slurry, respectively (rates according to Swiss fertilizer recommendations). We used two different approaches. Firstly, available (anion exchange resin extractable) and microbial P (hexanol labile P) were measured in fresh samples periodically taken throughout the vegetation period. Secondly, an isotopic dilution technique was applied on composite topsoil samples (0-5 cm) to determine rates of basal P mineralization and microbial immobilization of P in an incubation experiment. During the season available P ranged from 0.9-3.5, 5.3-11.2 and 1.9-6.7 mg kg-1 soil-1 and microbial P from 20-44, 43-59 and 61-93 mg kg-1 soil-1 in NK, NPK and NPKorg, respectively. Thus, microbial P was highest in NPKorg whereas available P was highest in NPK. Both P pools were lowest in NK. Average annual yield was lowest in NK (4.5 t ha-1), NPKorg (6.5 kg ha-1) and highest in NPK (7.5 t ha-1). However, no consistent relationship between changes in microbial and available P and plant productivity was found. Changes in weather conditions were reflected by changes in available and microbial P measured in the field. Phosphorus flushes were observed after dry periods (microbial P reduced and available P increased). Whereas fluctuations show microbial P release and P immobilization, an expected counteraction of microbial and available P could not be fully confirmed. In the incubation experiment microbial and available P were similar to average values in the field. A higher respiration rate measured in NPKorg indicated a higher microbial activity than in the other two treatments. Despite the differences in microbial P and respiration, the 33P recovery in the microbial biomass between 3 and 30 days of incubation was about 30% in all treatments. In conclusion we found complex interactions of available and microbial P with climate, fertilization, sward cutting and plant growth. An increased immobilization of P indicated by higher microbial P in the organic fertilized treatment was not confirmed in the isotope study. Gross and net mineralization data are still under analysis and will be presented at the conference.

  20. Extractable soil phosphorus in Blackland Prairie soils 

    E-print Network

    Byrd, Robert Claude

    1995-01-01

    The Texas Agricultural Extension Service (TAEX) Soil Testing Laboratory currently utilizes a single phosphorus (P) extractant consisting of 1.43 M NH4OAc, 1. 0 M HCl, and 0.025 M EDTA-PH 4.2 to estimate plant available P for all soils in Texas...

  1. AVAILABILITY OF PHOSPHORUS IN DAIRY FEEDS

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Three trials were conducted to measure phosphorus availability in feed ingredietns. In trial 1 and 2, 10 and 9 cows in mid to late lactation were fed for 3 wks a low P basal diet (BD) containing 0.17-0.19% P (dry basis). During the last 3-d of the third wk 12 fecal samples (dispersed through the 24-...

  2. EFFECT OF PHOSPHORUS TREATMENT ON LEAD MINERALOGY

    EPA Science Inventory

    Remediation of Pb-contaminated soils by amendments of phosphate may prove to be a viable way of sequestering Pb in the natural environment. Test plots of Pb-contaminated soil near Joplin, MO were treated with a variety of phosphorus-based amendments to observe the influence of co...

  3. REGULAR ARTICLE Contribution of phosphorus (32

    E-print Network

    Etxeberria, Edgardo

    Fernando C. Bachiega Zambrosi & Dirceu Mattos Jr. & Rodrigo M. Boaretto & José A. Quaggio & Takashi MuraokaREGULAR ARTICLE Contribution of phosphorus (32 P) absorption and remobilization for citrus growth & James P. Syvertsen Received: 7 September 2011 /Accepted: 14 December 2011 /Published online: 6 January

  4. PHOSPHORUS UPTAKE AND RELEASE FROM STREAM SEDIMENTS

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Phosphorus runoff from agricultural fields has been linked to freshwater eutrophication. However, edge-of-field P losses can be modified by benthic sediments during channel flow by physiochemical processes associated with Al, Fe, and Ca, and by biological assimilation. Thus, we investigated fluvial ...

  5. Phosphatase hydrolysis of organic phosphorus compounds

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Phosphatases are diverse groups of enzymes that deserve special attention because of the significant roles they play in mineralizing organic phosphorus (P) into inorganic available form. For getting more insight on the enzymatically hydrolysis of organic P, in this work, we compared the catalytic pa...

  6. Nutrient Management Module No. 4 Phosphorus Cycling,

    E-print Network

    Lawrence, Rick L.

    management 4.Be able to make a phosphorus fertilizer recommendation based on a soil test report 5.Recognize; 2) explaining the usefulness of P soil tests; 3) demonstrating how to make P fertilizer recommendations based on soil test results; and 4) discussing pros and cons of various P fertilizer management

  7. EXTRACTION OF SOLUBLE PHOSPHORUS IN SWINE LAGOONS

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A major problem in sustainability of animal production is excess of manure phosphorus (P) exceeding land assimilative capacity. Land application of manure results in P buildup in soil and increased potential for P losses through runoff and subsequent eutrophication of surface waters. A wastewater tr...

  8. THE PENNSYLVANIA PHOSPHORUS INDEX: VERSION 1

    Technology Transfer Automated Retrieval System (TEKTRAN)

    There has been increased attention focused on phosphorus (P) management because of water quality concerns resulting from eutrophication. In fresh water systems, elevated P inputs can lead to accelerated eutrophication and degraded water quality. Despite water quality concerns, adequate levels of s...

  9. Biological formation of volatile phosphorus compounds.

    PubMed

    Roels, J; Verstraete, W

    2001-09-01

    Phosphine and phosphides are reported to occur at numerous environmental sites such as fresh and marine sediments, landfills, faecal matter, biogas digesters and soils. The concentrations are several log units lower than the time-weighted average exposure standard, i.e. in the order of ng per m3 of gas or ng per kg material. Research about the biological formation of highly reduced gaseous phosphorus compounds dates back more than a hundred years. The early reports had to deal with a lot of scepticism. Thanks to new analytical tools (gas chromatography) it has become clear, during the last decade, that phosphine is a global constituent of the atmosphere. Pure strains of micro-organisms cultivated under highly anaerobic conditions were shown to produce phosphine. Thermodynamic considerations indicate that it is very improbable that the reduction of phosphate to phosphine is endergonic. Therefore the generation of phosphine cannot be compared with sulphidogenesis and methanogenesis. There seems to be a link between the existence of highly reactive gaseous phosphorus compounds and increased levels of metal corrosion. The reactive compounds could be formed by micro-organisms or they are liberated from phosphorus-containing impurities in the iron by the action of bacterial metabolites. The biochemical pathways responsible for the production of gaseous phosphorus compounds have not been characterised yet. PMID:11499578

  10. LUXURY CONSUMPTION OF PHOSPHORUS BY BENTHIC ALGAE

    EPA Science Inventory

    The ability of algal species to sequester phosphorus in their natural environment was evaluated. The amount of P sequestered was estimated by the density by polyphosphate (polyP) bodies within the cell. The abundance of polyP bodies was related to ambient P concentrations and tis...

  11. Photostability of thin exfoliated black phosphorus

    NASA Astrophysics Data System (ADS)

    Favron, Alexandre; Francoeur, Sébastien; Leonelli, Richard; Martel, Richard

    2014-03-01

    In its bulk form, black phosphorus has a direct gap of about 0.3 eV. Because of its lamellar structure, similar to that of graphite, black phosphorus can be exfoliated down to a single monolayer. The interesting properties is the possible tuning of the energy gap in the Near-IR using control of the layer thickness, which is of great interesting to develop sensors and other Near-IR optoelectronic devices. Preliminary studies on thin exfoliated layers revealed a fast photo-induced oxidation of black phosphorus, in room condition with an excitation higher than 1.8 eV. Using Raman spectroscopy as a probe of the quality and integrity of exfoliated layers, we present in this talk the results of a dynamical study of the photo-oxidation process at room temperature in a controlled atmosphere with the presence of the oxygen-water redox couple. A photo-induced charge transfer from black phosphorus to the redox couple is found to be responsible of the fast deterioration of the structure. Finally, we present Raman and Photoluminescence results on un-oxidized thin-layers measured at low temperature using different passivation schemes.

  12. Black Phosphorus Gas Sensors Ahmad N. Abbas ,

    E-print Network

    Zhou, Chongwu

    1 Black Phosphorus Gas Sensors Ahmad N. Abbas ,¶ , Bilu Liu , Liang Chen , Yuqiang Ma , Sen Cong comprised of a bottom monolayer CVD graphene electrode/BP/top (Ti/Au) electrode with a P++ Si/ 300 nm SiO2 back gated structure. Dashed line is a guide to the eye of the monolayer CVD graphene border. b, d) Id

  13. Phosphorus recovery and reuse from waste streams

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Phosphorus (P) is an important macro-nutrient required by higher plants for growth and development. Phosphate rock is the main raw material for P fertilizers and the global rock phosphate production stands at 191,000 thousand tonnes (t) in the year 2011 (Jaisinski, 2012). Phosphate rock is a scarce ...

  14. Phosphorus recovery and reuse from waste streams

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Phosphorus (P) is a macronutrient essential for all living organisms. Regrettably, it is a finite resource since phosphate rock (PR) is the main material used for production of P fertilizers. Globally, the demand for quality PR is escalating due to many factors including increasing human population....

  15. Fire-Resistant Polyamides Containing Phosphorus

    NASA Technical Reports Server (NTRS)

    Kourtides, Demetrius A.; Mikroyannidis, John A.

    1988-01-01

    Flammability and weight loss reduced. Fire-resistant polymers obtained from 1-{(dialkoxyphosphonyl) methyl}-2, 4- and -2, 6-diaminobenzenes by reaction with acyl or diacyl halides of higher functionality. Incorporation of compounds containing phosphorus into certain polymers shown previously to increase fire retardance. Discovery adds new class of polyamides to group of such polymers.

  16. Lability of Humic-Bound Phosphorus

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Phosphorus (P) has long been known to be present in humic substances from various sources. However, information on the lability of humic-bound P is very limited although such information is critical for understanding the role of humic substances in P cycling and nutrition. In this presentation, we d...

  17. Modeling Phosphorus in the Environment Review

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Phosphorus (P) is a key component of fertilizer inputs in plant agriculture and a critical ingredient of diets in animal nutrition. Elevated levels of environmental P and nitrogen have often resulted in algal blooms and accelerated eutrophication of lakes and streams, and degrade fragile ecosystems...

  18. Do soils loose phosphorus with dissolved organic matter?

    NASA Astrophysics Data System (ADS)

    Kaiser, K.; Brödlin, D.; Hagedorn, F.

    2014-12-01

    During ecosystem development and soil formation, primary mineral sources of phosphorus are becoming increasingly depleted. Inorganic phosphorus forms tend to be bound strongly to or within secondary minerals, thus, are hardly available to plants and are not leached from soil. What about organic forms of phosphorus? Since rarely studied, little is known on the composition, mobility, and bioavailability of dissolved organic phosphorus. There is some evidence that plant-derived compounds, such as phytate, bind strongly to minerals as well, while microbial compounds, such as nucleotides and nucleic acids, may represent more mobile fractions of soil phosphorus. In some weakly developed, shallow soils, leaching losses of phosphorus seem to be governed by mobile organic forms. Consequently, much of the phosphorus losses observed during initial stages of ecosystem development may be due to the leaching of dissolved organic matter. However, the potentially mobile microbial compounds are enzymatically hydrolysable. Forest ecosystems on developed soils already depleted in easily available inorganic phosphorus are characterized by rapid recycling of organic phosphors. That can reduce the production of soluble forms of organic phosphorus as well as increase the enzymatic hydrolysis and subsequent plant uptake of phosphorus bound within dissolved organic matter. This work aims at giving an outlook to the potential role of dissolved organic matter in the cycling of phosphorus within developing forest ecosystems, based on literature evidence and first results of ongoing research.

  19. Impact of Fish Farming on Phosphorus in Reservoir Sediments

    PubMed Central

    Jia, Binyang; Tang, Ya; Tian, Liyan; Franz, Leander; Alewell, Christine; Huang, Jen-How

    2015-01-01

    Fish farming has seriously influenced the aquatic environment in Sancha reservoir in SW China since 1985 and has been strongly restricted since 2005. Thus, phosphorus speciation in a sediment core dated between 1945 and 2010 at cm-resolution and in surface sediments from Sancha reservoir may allow us track how fish farming impacts phosphorus dynamics in lake sediments. Fish farming shifts the major binding forms of phosphorus in sediments from organic to residual phosphorus, which mostly originated from fish feed. Sorption to metal oxides and association with organic matters are important mechanisms for phosphorus immobilisation with low fish farming activities, whereas calcium-bound phosphorous had an essential contribution to sediment phosphorus increases under intensive fish framing. Notwithstanding the shifting, the aforementioned phosphorus fractions are usually inert in the lake environment, therefore changing phosphorus mobility little. The use of fish feed and water-purification reagents, the most important additives for fish farming, introduce not only phosphorus but also large amounts of sand-sized minerals such as quartz into the lake, to which phosphorus weakly sorbs. The sand-sized minerals as additional sorbents increase the pool of easily mobilisable phosphorus in sediments, which will slow down the recovery of reservoir water due to its rapid re-mobilisation. PMID:26577441

  20. Quantifying phosphorus and light effects in stream algae

    SciTech Connect

    Hill, Walter; Fanta, S.E.; Roberts, Brian J

    2009-01-01

    Simultaneous gradients of phosphorus and light were applied in experimental streams to develop quantitative relationships between these two important abiotic variables and the growth and composition of benthic microalgae. Algal biovolume and whole-stream metabolism responded hyperbolically to phosphorus enrichment, increasing approximately two-fold over the 5-300 g L-1 range of experimental phosphorus concentrations. The saturation threshold for phosphorus effects occurred at 25 g L-1 of soluble reactive phosphorus (SRP). Light effects were much stronger than those of phosphorus, resulting in a nearly ten-fold increase in algal biovolume over the 10-400 mol photons m-2 s-1 range of experimental irradiances. Biovolume accrual was light-saturated at 100 mol photons m-2 s-1 (5 mol photons m-2 d-1). Light effects were diminished by low phosphorus concentrations, and phosphorus effects were diminished by low irradiances, but evidence of simultaneous limitation by both phosphorus and light at subsaturating irradiances was weak. Contrary to the light:nutrient hypothesis, algal phosphorus content was not significantly affected by light, even in the lowest SRP treatments. However, algal nitrogen content increased substantially at lower irradiances, and it was very highly correlated with algal chlorophyll a content. Phosphorus enrichment in streams is likely to have its largest effect at concentrations <25 g L-1 SRP, but the effect of enrichment is probably minimized when streambed irradiances are kept below 2 mol photons m-2 d-1 by riparian shading or turbidity

  1. Impact of Fish Farming on Phosphorus in Reservoir Sediments.

    PubMed

    Jia, Binyang; Tang, Ya; Tian, Liyan; Franz, Leander; Alewell, Christine; Huang, Jen-How

    2015-01-01

    Fish farming has seriously influenced the aquatic environment in Sancha reservoir in SW China since 1985 and has been strongly restricted since 2005. Thus, phosphorus speciation in a sediment core dated between 1945 and 2010 at cm-resolution and in surface sediments from Sancha reservoir may allow us track how fish farming impacts phosphorus dynamics in lake sediments. Fish farming shifts the major binding forms of phosphorus in sediments from organic to residual phosphorus, which mostly originated from fish feed. Sorption to metal oxides and association with organic matters are important mechanisms for phosphorus immobilisation with low fish farming activities, whereas calcium-bound phosphorous had an essential contribution to sediment phosphorus increases under intensive fish framing. Notwithstanding the shifting, the aforementioned phosphorus fractions are usually inert in the lake environment, therefore changing phosphorus mobility little. The use of fish feed and water-purification reagents, the most important additives for fish farming, introduce not only phosphorus but also large amounts of sand-sized minerals such as quartz into the lake, to which phosphorus weakly sorbs. The sand-sized minerals as additional sorbents increase the pool of easily mobilisable phosphorus in sediments, which will slow down the recovery of reservoir water due to its rapid re-mobilisation. PMID:26577441

  2. Impact of Fish Farming on Phosphorus in Reservoir Sediments

    NASA Astrophysics Data System (ADS)

    Jia, Binyang; Tang, Ya; Tian, Liyan; Franz, Leander; Alewell, Christine; Huang, Jen-How

    2015-11-01

    Fish farming has seriously influenced the aquatic environment in Sancha reservoir in SW China since 1985 and has been strongly restricted since 2005. Thus, phosphorus speciation in a sediment core dated between 1945 and 2010 at cm-resolution and in surface sediments from Sancha reservoir may allow us track how fish farming impacts phosphorus dynamics in lake sediments. Fish farming shifts the major binding forms of phosphorus in sediments from organic to residual phosphorus, which mostly originated from fish feed. Sorption to metal oxides and association with organic matters are important mechanisms for phosphorus immobilisation with low fish farming activities, whereas calcium-bound phosphorous had an essential contribution to sediment phosphorus increases under intensive fish framing. Notwithstanding the shifting, the aforementioned phosphorus fractions are usually inert in the lake environment, therefore changing phosphorus mobility little. The use of fish feed and water-purification reagents, the most important additives for fish farming, introduce not only phosphorus but also large amounts of sand-sized minerals such as quartz into the lake, to which phosphorus weakly sorbs. The sand-sized minerals as additional sorbents increase the pool of easily mobilisable phosphorus in sediments, which will slow down the recovery of reservoir water due to its rapid re-mobilisation.

  3. Phosphorus Equilibria Among Mafic Silicate Phases

    NASA Technical Reports Server (NTRS)

    Berlin, Jana; Xirouchakis, Dimitris

    2002-01-01

    Phosphorus incorporation in major rock-forming silicate minerals has the following implications: (1) Reactions between phosphorus-hosting major silicates and accessory phosphates, which are also major trace element carriers, may control the stability of the latter and thus may affect the amount of phosphorus and other trace elements released to the coexisting melt or fluid phase. (2) Less of a phosphate mineral is needed to account for the bulk phosphorus of planetaty mantles. (3) During partial melting of mantle mineral assemblages or equilibrium fractional crystallization of basaltic magmas, and in the absence or prior to saturation with a phosphate mineral, silicate melts may become enriched in phosphorus, especially in the geochemically important low melt fraction regime, Although the small differences in the ionic radii of IVp5+, IVSi4+, and IV Al3+ makes phosphoms incorporation into crystalline silicates perhaps unsurprising, isostructural silicate and phosphate crystalline solids do not readily form solutions, e.g., (Fe, Mg)2SiO4 vs. LiMgPO4, SiO)2 VS. AlPO4. Nonetheless, there are reports of, poorly characterized silico-phosphate phases in angrites , 2-4 wt% P2O5 in olivine and pyroxene grains in pallasites and reduced terestrial basalts which are little understood but potentially useful, and up to 17 wt% P2O5 in olivine from ancient slags. However, such enrichments are rare and only underscore the likelihood of phosphoms incorporation in silicate minerals. The mechanisms that allow phosphorus to enter major rock-forming silicate minerals (e.g., Oliv, Px, Gt) remain little understood and the relevant data base is limited. Nonetheless, old and new high-pressure (5-10 GPa) experimental data suggest that P2O5 wt% decreases from silica-poor to silica-rich compositions or from orthosilicate to chain silicate structures (garnet > olivine > orthopyroxene) which implies that phosphorus incorporation in silicates is perhaps more structure-than site-specific. The data also indicate that DXVliQP2O5 decrease in the same order, but DOVLiQP2O5 and DOpx/LiQP205 are likely constant, respectively equal to 0.08(3) and 0.007(4), in contrast, DG1ILiQP205 increases from 0.15(3) to 0.36(10) as garnet becomes majoritic, thus silica-enriched, and may also depend on liquid composition (SiO2, P2O5 and Na2O wt%).

  4. Continuous nasogastric phosphorus infusion in hypophosphatemic rickets of prematurity.

    PubMed

    Koo, W W; Antony, G; Stevens, L H

    1984-02-01

    Radiologic and biochemical abnormalities associated with nutritional hypophosphatemic rickets were discovered in a 945-g preterm infant despite daily supplementation with 800 to 1,600 IU of ergocalciferol (vitamin D2) and an elevated serum 25-hydroxyvitamin D concentration. Vitamin D supplementation was stopped, and the rickets was corrected by phosphorus supplement alone with the use of a unique technique of long-term, continuous nasogastric phosphorus infusion. Normophosphatemia was rapidly achieved and effectively maintained. Hypocalcemia did not occur at rates of infusion of 100 mg of elemental phosphorus per day. The data are consistent with specific phosphorus deficiency as the cause of rickets in this infant, rather than insufficient vitamin D intake or disturbed vitamin D metabolism. We speculated that continuous phosphorus infusion prevents the intermittent hyperphosphatemia of bolus phosphorus supplement and that continuous phosphorus infusion may be useful in the treatment of other hypophosphatemic states of infancy. PMID:6695874

  5. Electroless Nickel Phosphorus Plating on AZ31

    NASA Astrophysics Data System (ADS)

    Shartal, Kh. M.; Kipouros, G. J.

    2009-04-01

    One of the major drawbacks to using magnesium parts in automotive applications is poor corrosion resistance, which can be improved with a nickel-boron coating placed on a nickel-phosphorus coating, which, in turn, is placed on a phosphate-permanganate conversion-coating layer produced on the magnesium alloy AZ31. This work reports on the determination of the optimum kinetic parameters for producing a coherent nickel-phosphorus coating using an electroless-procedure phosphate-permanganate conversion-coating layer and for studying the effects of the experimental variables of the electroless plating process on the phosphorus content, surface morphology, and structure of the electroless nickel-phosphorus (EN-P) coatings produced. Measurements of the plating rate as a function of experimental variables such as the compositions of the plating bath constituents, temperature, and pH were implemented using the weight-gain method; the phosphorus content of the EN-P coatings was measured using energy-dispersive spectroscopy (EDS) analysis. The surface morphology of the coating was examined using a scanning electron microscope (SEM); X-ray diffraction (XRD) was used to characterize the structure of each coating. An empirical rate law was determined for EN-P plating on a phosphate-permanganate conversion coating. It is found that the deposition rate of the EN-P coating increases by increasing the deposition temperature, the concentration of free nickel ions, and the concentration of hypophosphite ions in the plating bath. In addition, the deposition rate decreases by increasing both the plating bath pH and the concentration of citric acid in the plating bath.

  6. Phosphorus Recycling from an Unexplored Source by Polyphosphate Accumulating Microalgae and Cyanobacteria—A Step to Phosphorus Security in Agriculture

    PubMed Central

    Mukherjee, Chandan; Chowdhury, Rajojit; Ray, Krishna

    2015-01-01

    Phosphorus (P), an essential element required for crop growth has no substitute. The global food security depends on phosphorus availability in soil for crop production. World phosphorus reserves are fast depleting and with an annual increase of 2.3% in phosphorus demand, the current reserves will be exhausted in coming 50–100 years. India and other Western countries are forced to import phosphorus fertilizers at high costs to meet their agricultural demands due to uneven distribution of phosphate rocks on earth. The present study from India, aims to draw attention to an unnoticed source of phosphorus being wasted as parboiled rice mill effluent and subsequent bio-recovery of the valuable element from this unconventional source. The research was conducted in West Bengal, India, a state with the highest number of parboiled rice mills where its effluent carries on an average ~40 mg/L of soluble phosphorus. Technology to recover and recycle this wastewater P in India in a simple, inexpensive mode is yet to be optimized. Our strategy to use microalgae, Chlorella sp. and cyanobacteria, Cyanobacterium sp., Lyngbya sp., and Anabaena sp. to sequester the excess phosphorus from the effluent as polyphosphate inclusions and its subsequent recycling as slow and moderate release phosphorus biofertilizers to aid plant growth, preventing phosphorus loss and pollution, is a contemporary venture to meet the need of the hour. These polyphosphate accumulating microorganisms play a dual role of remediation and recovery of phosphorus, preliminarily validated in laboratory scale.

  7. Phosphorus limitation strategy to increase propionic acid flux towards 3-hydroxyvaleric acid monomers in Cupriavidus necator.

    PubMed

    Grousseau, Estelle; Blanchet, Elise; Déléris, Stéphane; Albuquerque, Maria G E; Paul, Etienne; Uribelarrea, Jean-Louis

    2014-02-01

    Properties of polyhydroxybutyrate-co-hydroxyvalerate (P(3HB-co-3HV)) depend on their 3HV content. 3HV can be produced by Cupriavidus necator from propionic acid. Few studies explored carbon distribution and dynamics of 3HV and 3HB monomers production, and none of them have been done with phosphorus as limiting nutrient. In this study, fed-batch cultures of C. necator with propionic acid, as sole carbon source or mixed with butyric acid, were performed. Phosphorus deficiency allowed sustaining 3HV production rate and decreasing 3HB production rate, leading to an instant production of up to 100% of 3HV. When a residual growth is sustained by a phosphorus feeding, the maximum 3HV percentage produced from propionic acid is limited to 33% (Mole.Mole(-1)). The association of a second carbon source like butyric acid lead to higher conversion of propionic acid into 3HV. This study showed the importance of the limiting nutrient and of the culture strategy to get the appropriate product. PMID:24365742

  8. Roasting-induced phase change and its influence on phosphorus removal through acid leaching for high-phosphorus iron ore

    NASA Astrophysics Data System (ADS)

    Yang, Min; Zhu, Qing-shan; Fan, Chuan-lin; Xie, Zhao-hui; Li, Hong-zhong

    2015-04-01

    In the present study, roasting-induced phase change and its influence on phosphorus removal via leaching has been investigated for high-phosphorus iron ore. The findings indicate that phosphorus in the ore is associated with goethite and exists mainly in amorphous Fe3PO7 phase. The phosphorus remains in the amorphous phase after being roasted below 300°C. Grattarolaite (Fe3PO7) is found in samples roasted at 600-700°C, revealing that phosphorus phase is transformed from the amorphous form to crystalline grattarolaite during roasting. Leaching tests on synthesized pure grattarolaite reveal a low rate of phosphorus removal by sulfuric acid leaching. When the roasting temperature is higher than 800°C, grattarolaite is found to react with alumina to form aluminum phosphate, and the reactivity of grattarolaite with alumina increases with increasing roasting temperature. Consequently, the rate of phosphorus removal also increases with increasing roasting temperature due to the formation of acid-soluble aluminum phosphate.

  9. Distribution Characteristics of Phosphorus in the Sediments and Overlying Water of Poyang Lake

    PubMed Central

    Wang, Lingqing; Liang, Tao

    2015-01-01

    Phosphorus (P) is a key indicator of the aquatic organism growth and eutrophication in lakes. The distribution and speciation of P and its release characteristics from sediments were investigated by analyzing sediment and water samples collected during high flow and low flow periods. Results showed that the average concentrations (ranges) of total phosphorus (TP) in the surface and deep water were 0.06 mg L-1 (0.03–0.13 mg L-1) and 0.15 mg L-1 (0.06–0.33 mg L-1), respectively, while the average concentration (range) of TP in sediments was 709.17 mg kg-1 (544.76–932.11 mg kg-1). The concentrations of TP and different forms of P varied spatially in the surface sediments, displaying a decreasing trend from south to north. P also varied topographically from estuarine areas to lake areas. The vertical distribution of TP and different forms of P were observed to decrease as depth increased. The P concentrations during the low flow period were higher than those during the high flow period. Inorganic phosphorus (IP) was the dominant form of P, accounting for 61%–82% of TP. The concentration of bioavailable phosphorus in sediments was relatively large, indicating a high risk of release to overlying water. The simulation experiment of P release from sediments showed that the release was relatively fast in the first 0-5 min and then decreased to a plateau after 1 hr. Approximately 84–89% of the maximum amount of P was released during the first hour. PMID:25938758

  10. Phosphorus Migration During Direct Reduction of Coal Composite High-Phosphorus Iron Ore Pellets

    NASA Astrophysics Data System (ADS)

    Cheng, Cheng; Xue, Qingguo; Wang, Guang; Zhang, Yuanyuan; Wang, Jingsong

    2015-10-01

    This study investigated the direct reduction process and phosphorus migration features of high-phosphorus iron ores using simulated experiments. Results show that iron oxide was successfully reduced, and a Fe-Si-Al slag formed in carbon-bearing pellets at 1473 K (1200 °C). Fluorapatite then began to decompose into Ca3(PO4)2 and CaF2. As the reaction continued, Ca3(PO4)2 and Fe-Si-Al slag reacted quickly with each other to generate CaAl2Si2O8 and P2, while CaF2 turned into SiF4 gas in the presence of high SiO2. A small amount remained in the slag phase and formed CaAl2Si2O8. Further analysis detailed the migration process of the phosphorus into iron phases, as well as the relationship between carburization and phosphorus absorption in the iron phases. As carbon content in the iron phase increased, the austenite grain boundary melted and formed a large quantity of liquid iron which quickly absorbed the phosphorus. Based on the results of simulation and analysis, this paper proposed a method which reduced the absorption of P by the metallic iron formed and reduced P content in metallic iron during direct reduction.

  11. Black Phosphorus: Narrow Gap, Wide Applications.

    PubMed

    Castellanos-Gomez, Andres

    2015-11-01

    The recent isolation of atomically thin black phosphorus by mechanical exfoliation of bulk layered crystals has triggered an unprecedented interest, even higher than that raised by the first works on graphene and other two-dimensionals, in the nanoscience and nanotechnology community. In this Perspective, we critically analyze the reasons behind the surge of experimental and theoretical works on this novel two-dimensional material. We believe that the fact that black phosphorus band gap value spans over a wide range of the electromagnetic spectrum (interesting for thermal imaging, thermoelectrics, fiber optics communication, photovoltaics, etc.) that was not covered by any other two-dimensional material isolated to date, its high carrier mobility, its ambipolar field-effect, and its rather unusual in-plane anisotropy drew the attention of the scientific community toward this two-dimensional material. Here, we also review the current advances, the future directions and the challenges in this young research field. PMID:26600394

  12. Mechanical strain effects on black phosphorus nanoresonators.

    PubMed

    Wang, Cui-Xia; Zhang, Chao; Jiang, Jin-Wu; Park, Harold S; Rabczuk, Timon

    2015-12-23

    We perform classical molecular dynamics simulations to investigate the effects of mechanical strain on single-layer black phosphorus nanoresonators at different temperatures. We find that the resonant frequency is highly anisotropic in black phosphorus due to its intrinsic puckered configuration, and that the quality factor in the armchair direction is higher than in the zigzag direction at room temperature. The quality factors are also found to be intrinsically larger than those in graphene and MoS2 nanoresonators. The quality factors can be increased by more than a factor of two by applying tensile strain, with uniaxial strain in the armchair direction being the most effective. However, there is an upper bound for the quality factor increase due to nonlinear effects at large strains, after which the quality factor decreases. The tension induced nonlinear effect is stronger along the zigzag direction, resulting in a smaller maximum strain for quality factor enhancement. PMID:26649476

  13. Black phosphorus field-effect transistors.

    PubMed

    Li, Likai; Yu, Yijun; Ye, Guo Jun; Ge, Qingqin; Ou, Xuedong; Wu, Hua; Feng, Donglai; Chen, Xian Hui; Zhang, Yuanbo

    2014-05-01

    Two-dimensional crystals have emerged as a class of materials that may impact future electronic technologies. Experimentally identifying and characterizing new functional two-dimensional materials is challenging, but also potentially rewarding. Here, we fabricate field-effect transistors based on few-layer black phosphorus crystals with thickness down to a few nanometres. Reliable transistor performance is achieved at room temperature in samples thinner than 7.5 nm, with drain current modulation on the order of 10(5) and well-developed current saturation in the I-V characteristics. The charge-carrier mobility is found to be thickness-dependent, with the highest values up to ? 1,000 cm(2) V(-1) s(-1) obtained for a thickness of ? 10 nm. Our results demonstrate the potential of black phosphorus thin crystals as a new two-dimensional material for applications in nanoelectronic devices. PMID:24584274

  14. Phosphorus, a key to life on the primitive earth

    NASA Technical Reports Server (NTRS)

    Griffith, E. J.; Ponnamperuma, C.; Gabel, N. W.

    1977-01-01

    The phosphorus of the primitive earth was present as phosphates. It is strongly probable that a portion of the phosphate was present as condensed phosphates. The primitive earth was highly deficient in the total available phosphorus until a sufficient quantity of phosphorus weathered from the igneous rocks in which it was entrapped. Approximately three billion years were required for the seas to become saturated. Until this time passed the seas acted as a giant sink for phosphorus, diluting it to the extent that all forms of life were deprived of the vital nutrient. When the seas became saturated, the rate of turnover of the phosphorus increased rapidly. As the seas pulsated, they left the excess precipitate phosphorus as sedimentary rock in locally rich deposits on which life could thrive.

  15. Electronic Properties of Few-layer Black Phosphorus

    NASA Astrophysics Data System (ADS)

    Li, Likai; Yu, Yijun; Ye, G. J.; Chen, X. H.; Zhang, Yuanbo

    2013-03-01

    Black phosphorus is a layered allotropy of phosphorus that closely resembles graphite. In a single atomic layer, phosphorus atoms are covalently bonded into a puckered honey comb structure. All five valence electrons are localized, so unlike graphene monolayer black phosphorus is a semiconductor with a band gap of ~ 2 eV. In a bulk crystal the interlayer coupling reduces the band gap to ~ 0.3 eV. Using mechanical exfoliation method, we have successfully fabricated few layer black phosphorus field effect transistors. Our samples exhibit bipolar behavior with on-off ratio up to 106, and a low off-state current. Electronic mobilities up to ~ 1000 cm2V-1s-1 are currently achieved, with possibilities for further improvement. Such characteristics make black phosphorus a potential candidate for future nanoelectronic applications.

  16. Where is the Phosphorus in Cometary Volatiles?

    NASA Astrophysics Data System (ADS)

    Boice, Daniel C.; de Almeida, Amaury

    2015-08-01

    Phosphorus is a key element in all living organisms but its role in life's origin is not well understood. Phosphorus-bearing compounds have been observed in space, are ubiquitous in meteorites in small quantities, and have been detected as part of the dust component in comets Halley and Wild 2. However, searches for P-bearing species in the gas phase in cometary comae have been unsuccessful. We present results of the first quantitative study of P-bearing molecules in comets to identify likely species containing phosphorus. We found reaction pathways of gas-phase and photolytic chemistry for simple P-bearing molecules likely to be found in comets and important for prebiotic chemistry. We hope to aid future searches for this important element, especially the Rosetta Mission to Comet 67P/Churyumov-Gerasimenko, possibly shedding light on issues of comet formation (time and place) and understanding prebiotic to biotic evolution of life.Acknowledgements: We greatly appreciate support from the NSF Planetary Astronomy Program under Grant No. 0908529 and the Instituto de Astronomia, Geofísica e Ciências Atmosféricas at the University of São Paulo.

  17. Redox chemistry in the phosphorus biogeochemical cycle

    PubMed Central

    Pasek, Matthew A.; Sampson, Jacqueline M.; Atlas, Zachary

    2014-01-01

    The element phosphorus (P) controls growth in many ecosystems as the limiting nutrient, where it is broadly considered to reside as pentavalent P in phosphate minerals and organic esters. Exceptions to pentavalent P include phosphine—PH3—a trace atmospheric gas, and phosphite and hypophosphite, P anions that have been detected recently in lightning strikes, eutrophic lakes, geothermal springs, and termite hindguts. Reduced oxidation state P compounds include the phosphonates, characterized by C?P bonds, which bear up to 25% of total organic dissolved phosphorus. Reduced P compounds have been considered to be rare; however, the microbial ability to use reduced P compounds as sole P sources is ubiquitous. Here we show that between 10% and 20% of dissolved P bears a redox state of less than +5 in water samples from central Florida, on average, with some samples bearing almost as much reduced P as phosphate. If the quantity of reduced P observed in the water samples from Florida studied here is broadly characteristic of similar environments on the global scale, it accounts well for the concentration of atmospheric phosphine and provides a rationale for the ubiquity of phosphite utilization genes in nature. Phosphine is generated at a quantity consistent with thermodynamic equilibrium established by the disproportionation reaction of reduced P species. Comprising 10–20% of the total dissolved P inventory in Florida environments, reduced P compounds could hence be a critical part of the phosphorus biogeochemical cycle, and in turn may impact global carbon cycling and methanogenesis. PMID:25313061

  18. Redox chemistry in the phosphorus biogeochemical cycle.

    PubMed

    Pasek, Matthew A; Sampson, Jacqueline M; Atlas, Zachary

    2014-10-28

    The element phosphorus (P) controls growth in many ecosystems as the limiting nutrient, where it is broadly considered to reside as pentavalent P in phosphate minerals and organic esters. Exceptions to pentavalent P include phosphine--PH3--a trace atmospheric gas, and phosphite and hypophosphite, P anions that have been detected recently in lightning strikes, eutrophic lakes, geothermal springs, and termite hindguts. Reduced oxidation state P compounds include the phosphonates, characterized by C-P bonds, which bear up to 25% of total organic dissolved phosphorus. Reduced P compounds have been considered to be rare; however, the microbial ability to use reduced P compounds as sole P sources is ubiquitous. Here we show that between 10% and 20% of dissolved P bears a redox state of less than +5 in water samples from central Florida, on average, with some samples bearing almost as much reduced P as phosphate. If the quantity of reduced P observed in the water samples from Florida studied here is broadly characteristic of similar environments on the global scale, it accounts well for the concentration of atmospheric phosphine and provides a rationale for the ubiquity of phosphite utilization genes in nature. Phosphine is generated at a quantity consistent with thermodynamic equilibrium established by the disproportionation reaction of reduced P species. Comprising 10-20% of the total dissolved P inventory in Florida environments, reduced P compounds could hence be a critical part of the phosphorus biogeochemical cycle, and in turn may impact global carbon cycling and methanogenesis. PMID:25313061

  19. The Cytotoxicity of Layered Black Phosphorus.

    PubMed

    Latiff, Naziah Mohamad; Teo, Wei Zhe; Sofer, Zdenek; Fisher, Adrian C; Pumera, Martin

    2015-09-28

    Black phosphorus (BP), the latest addition to the family of 2D layered materials, has attracted much interest owing to potential optoelectronics, nanoelectronics, and biomedicine applications. Little is known about its toxicity, such as whether it could be as toxic as white phosphorus. In response to the possibility of BP employment into commercial products and biomedical devices, its cytotoxicity to human lung carcinoma epithelial cells (A549) was investigated. Following a 24?h exposure of the cells with different BP concentrations, cell viability assessments were conducted using water-soluble tetrazolium salt (WST-8) and methylthiazolyldiphenyltetrazolium bromide (MTT) assays. The toxicological effects were found to be dose-dependent, with BP reducing cell viabilities to 48% (WST-8) and 34% (MTT) at 50??g?mL(-1) exposure. This toxicity was observed to be generally intermediate between that of graphene oxides and exfoliated transition-metal dichalcogenides (MoS2, WS2, WSe2). The relatively low toxicity paves the way to utilization of black phosphorus. PMID:26291565

  20. Benthic phosphorus regeneration in the Potomac River Estuary

    USGS Publications Warehouse

    Callender, E.

    1982-01-01

    The flux of dissolved reactive phosphate from Potomac riverine and estuarine sediments is controlled by processes occurring at the water-sediment interface and within surficial sediment. In situ benthic fluxes (0.1 to 2.0 mmoles m-2 day-1) are generally five to ten times higher than calculated diffusive fluxes (0.020 to 0.30 mmoles m-2 day-1). The discrepancy between the two flux estimates is greatest in the transition zone (river mile 50 to 70) and is attributd to macrofaunal irrigation. Both in situ and diffusive fluxes of dissolved reactive phosphate from Potomac tidal river sediments are low while those from anoxic lower estuarine sediments are high. The net accumulation rate of phosphorus in benthic sediment exhibits an inverse pattern. Thus a large fraction of phosphorus is retained by Potomac tidal river sediments, which contain a surficial oxidized layer and oligochaete worms tolerant of low oxygen conditions, and a large fraction of phosphorus is released from anoxic lower estuary sediments. Tidal river sediment pore waters are in equilibrium with amorphous Fe (OH)3 while lower estuary pore waters are significantly undersaturated with respect to this phase. Benthic regeneration of dissolved reactive phosphorus is sufficient to supply all the phosphorus requirements for net primary production in the lower tidal river and transition-zone waters of the Potomac River Estuary. Benthic regeneration supplies approximately 25% as much phosphorus as inputs from sewage treatment plants and 10% of all phosphorus inputs to the tidal Potomac River. When all available point source phosphorus data are put into a steady-state conservation of mass model and reasonable coefficients for uptake of dissolved phosphorus, remineralization of particulate phosphorus, and sedimentation of particulate phosphorus are used in the model, a reasonably accurate simulation of dissolved and particulate phosphorus in the water column is obtained for the summer of 1980. ?? 1982 Dr W. Junk Publishers.

  1. Understanding soil phosphorus systems from emergent phosphorus behaviour in a headwater catchment

    NASA Astrophysics Data System (ADS)

    Ockenden, Mary; Beven, Keith; Collins, Adrian; Evans, Bob; Falloon, Pete; Hiscock, Kevin; Hollaway, Michael; Kahana, Ron; Macleod, Kit; Ross, Kirsty; Wearing, Catherine; Withers, Paul; Zhou, Jian; Benskin, Clare; Burke, Sean; EdenDTC Team; Haygarth, Phil

    2015-04-01

    Knowledge of soil phosphorus (P) sources and pathways is essential for predicting P transfers to water in the future, when drivers of P biogeochemistry may change under climate and land use change. However, the understanding of high frequency phosphorus dynamics has been limited by data of insufficient temporal resolution. This study shows how observing the patterns shown by headwater catchment systems can help to improve understanding of soil system science. The study describes analysis of 15 minute resolution data of rainfall and river discharge, and 30 minute resolution data of total phosphorus (TP) and total reactive phosphorus (TRP) concentrations from a sub-basin of the River Eden catchment, Cumbria, UK, collected by the Defra Demonstration Test Catchment Programme. The analysis focussed on extreme events and event sequences, which are predicted to occur more frequently under a changing climate, such as periods of drying followed by heavy rainfall. Events were classified according to exceedance of discharge and P concentration thresholds (Type 1 = high discharge, low TP; Type 2 = high discharge, high TP; Type 3 = low discharge, high TP). More than 75% of the TP load was transported during the 5% of the time with highest river discharge, with more than 69% of the TP load transferred in Type 2 events (< 4% in Type 1 events). High phosphorus concentrations in the river were also recorded during rainfall events following a dry period, when there was little response in discharge (Type 3, which accounted for less than 2% of total load). A lag of around one hour between peak TP and peak TRP concentrations indicated different pathways, with TP influenced by quickly mobilised sources, such as a readily available soil P pool, and fast pathways. In contrast, TRP showed a slower response indicating the presence of slower sub-surface pathways. Improved understanding of these processes will help in understanding the importance and availability of soil P pools in order to help farmers to plan sustainable phosphorus use and appropriate land management.

  2. 76 FR 31824 - Chemical Mixtures Containing Listed Forms of Phosphorus and Change in Application Process

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-06-02

    ...power tools. DEA has not identified any chemical mixtures containing white phosphorus. Diversion of Chemical Mixtures Containing Regulated Phosphorus...phosphorus plays an important role in the chemical reaction to produce methamphetamine, a...

  3. Phosphorus water quality model evaluation and comparison for natural and constructed wetlands 

    E-print Network

    Paasch, Mary Margaret

    1998-01-01

    numerical models have been developed to predict total phosphorus outflow concentrations and annual phosphorus retention within treatment wetlands. Three phosphorus models, the mass balance model with first order areal uptake, the Vollenweider-based wetland...

  4. 21 CFR 862.1580 - Phosphorus (inorganic) test system.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ...ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES CLINICAL CHEMISTRY AND CLINICAL TOXICOLOGY DEVICES Clinical Chemistry Test Systems § 862.1580 Phosphorus (inorganic) test system. (a)...

  5. Method of removing and detoxifying a phosphorus-based substance

    DOEpatents

    Vandegrift, G.F.; Steindler, M.J.

    1985-05-21

    A method of removing a phosphorus-based poisonous substance from water contaminated is presented. In addition, the toxicity of the phosphorus-based substance is also subsequently destroyed. A water-immiscible organic solvent is first immobilized on a supported liquid membrane before the contaminated water is contacted with one side of the supported liquid membrane to absorb the phosphorus-based substance in the organic solvent. The other side of the supported liquid membrane is contacted with a hydroxy-affording strong base to react with phosphorus-based solvated species to form a non-toxic product.

  6. Water quality criteria for white phosphorus: Final report. [Contains glossary

    SciTech Connect

    Davidson, K.A.; Hovatter, P.S.; Sigmon, C.F.

    1987-08-01

    Data obtained from a review of the literature concerning the environmental fate and aquatic and mammalian toxicity of white phosphorus are presented to derive Water Quality Criteria for the protection of humans and aquatic organisms and their uses. Laboratory and field studies indicate that white phosphorus is quite toxic to aquatic organisms, with fish being more sensitive than macroinvertebrates. Bioaccumulation is rapid and extensive, with the greatest uptake in the liver and muscle of fish and the hepatopancreas of lobster; however, depuration occurs within 7 days postexposure. Other toxic effects to aquatic organisms include cardiovascular and histological changes. Field studies indicate that effluents containing white phosphorus adversely affect receiving aquatic systems by decreasing diversity and increasing mortality of select species. Acute exposure to white phosphorus causes similar effects in laboratory animals and humans. In the absence of medical treatment, the estimated minimal lethal dose of white phosphorus in humans is 100 mg (1.4 mg/kg). Following ingestion, organs damaged by white phosphorus are the gastrointestinal tract, liver, kidney, brain, and cardiovascular system. Chronic and subchronic exposure of laboratory animals to white phosphorus by oral or subcutaneous routes results in reduced growth, reduced survival at high does, increased survival at low doses, and bone pathology. Humans chronically exposed to white phosphorus in the occupational environment develop a specific lesion (different from that observed in laboratory animals) called phosphorus necrosis of the jawbone or ''phossy jaw.'' 139 refs., 1 fig., 18 tabs.

  7. NMR and mass spectrometry of phosphorus in wetlands

    USGS Publications Warehouse

    El-Rifai, H.; Heerboth, M.; Gedris, T.E.; Newman, S.; Orem, W.; Cooper, W.T.

    2008-01-01

    There is at present little information on the long-term stability of phosphorus sequestered in wetlands. Phosphorus sequestered during high loading periods may be relatively unstable and easily remobilized following changes in nutrient status or hydrological regime, but the chemical forms of sequestered phosphorus that do remobilize are largely unknown at this time. A lack of suitable analytical techniques has contributed to this dearth of knowledge regarding the stability of soil organic phosphorus. We analysed phosphorus in soils from the 'head' of Rescue Strand tree island and an adjacent marsh in the Florida Everglades by 31P nuclear magnetic resonance (NMR) spectroscopy and high-resolution mass spectrometry. Tree islands are important areas of biodiversity within the Everglades and offer a unique opportunity to study phosphorus sequestration because they are exposed to large phosphorus loads and appear to be natural nutrient sinks. The 31P NMR profiling of extracts from surface and sediment samples in the tree island indicates that phosphorus input to Rescue Strand tree island soils is mostly in the form of inorganic ortho-phosphate and is either refractory when deposited or rapidly recycled by the native vegetation into a stable phosphorus pool largely resistant to re-utilization by plants or microbes. Mass spectrometry revealed the presence of inositol hexakisphosphate, a common organic monophosphate ester not previously observed in Everglades' soils. ?? 2008 The Authors.

  8. Phosphorus deposition from the epilimnion of Onondaga Lake

    SciTech Connect

    Not Available

    1985-07-01

    The downward flux of inorganic and organic fractions of phosphorus from the epilimnion of calcium-rich, hypereutrophic, Onondaga Lake was determined over 7 months in the water and in sediment traps. Material was collected in sediment traps for short and long periods (average of 4 and 14 days) throughout the study. A linear relationship between overlying concentrations of particulate phosphorus and downward flux (mg P m/sup -2/d/sup -1/) of phosphorus was only weakly supported (significant at the 99.5% confidence level, r/sup 2/ = 0.156). About 30% of the phosphorus deposited was in inorganic form. The time-averaged flux of particulate phosphorus (45.4 mg P m/sup -2/ d/sup -1/) was greater than any values in the literature for other systems. The substantial contribution of inorganic phosphorus to total phosphorus deposition and the large magnitude of the overall downward flux may be attributed to oversaturation with respect to the solubility of calcite in the epilimnion of the lake, which facilitates the sedimentation of phosphorus with calcite and may also enhance the settling of phytoplankton cells. A comparison of the sediment trap data with annual mass balance calculations suggests that phosphorus settling across the metalimnion cycles vertically on the average about three times before it is exported from the lake or incorporated into the sediments.

  9. Ascorbic acid, calcium, phosphorus and magnesium intake variations: effects on calcium, phosphorus and magnesium utilization by human adults

    SciTech Connect

    Kies, C.; Brennan, M.A.; Parks, S.K.; Stauffer, D.J.; Wang, H.Y.; Young, S.F.; Fox, H.M.

    1986-03-01

    The objective of the study was to determine the effects of feeding two levels of ascorbic acid, calcium, phosphorus, magnesium and ascorbic acid on the apparent utilization of calcium, phosphorus and magnesium by healthy, human adult subjects. During 4 randomly-arranged experimental periods of 7 days each, a laboratory-controlled diet alone or with supplements of ascorbic acid, dicalcium phosphate or magnesium oxide was fed to the 18 subjects. Results indicated that ascorbic acid supplementation tended to reduce urinary phosphorus loss and to slightly increase fecal phosphorus loss so that overall phosphorus balances became more positive. Conversely, under these conditions, urinary calcium losses were little affected but fecal calcium losses were increased resulting in an overall decrease in calcium balance with ascorbic acid supplementation. Ascorbic acid supplementation resulted in decreased urine and fecal losses of magnesium and more positive magnesium balances. Magnesium supplementation resulted in more positive calcium and phosphorus balances as did calcium phosphate supplementation on magnesium balance.

  10. A novel approach for phosphorus recovery and no wasted sludge in enhanced biological phosphorus removal process with external COD addition.

    PubMed

    Xia, Cheng-Wang; Ma, Yun-Jie; Zhang, Fang; Lu, Yong-Ze; Zeng, Raymond J

    2014-01-01

    In enhanced biological phosphorus removal (EBPR) process, phosphorus (P) in wastewater is removed via wasted sludge without actual recovery. A novel approach to realize phosphorus recovery with special external chemical oxygen demand (COD) addition in EBPR process was proposed. During the new operating approach period, it was found that (1) no phosphorus was detected in the effluent; (2) with an external addition of 10 % of influent COD amount, 79 % phosphorus in the wastewater influent was recovered; (3) without wasted sludge, the MLVSS concentration in the system increased from 2,010 to 3,400 mg/L and kept stable after day 11 during 24-day operating period. This demonstrates that the novel approach is feasible to realize phosphorus recovery with no wasted sludge discharge in EBPR process. Furthermore, this approach decouples P removal and sludge age, which may enhance the application of membrane bioreactor for P removal. PMID:24122666

  11. The content of available mineral phosphorus compounds in chestnut soils of Northern Mongolia upon application of different forms of phosphorite

    NASA Astrophysics Data System (ADS)

    Ubugunov, L. L.; Enkhtuyaa, B.; Merkusheva, M. G.

    2015-06-01

    The effect of different forms of phosphorite (activated and crude ground) of the Burenkhansk deposit on the phosphate status of chestnut soils and the productivity of spring wheat was studied in Northern Mongolia. It was found that the transformation of mineral soil phosphates upon the application of activated phosphorite (together with NK) is similar to that upon superphosphate application, and the available phosphorus concentration is even a gradation higher. The application of crude ground phosphorite helped to preserve the content of mineral phosphates in the soil at the initial level. Optimum concentrations of available phosphorus and the sum of loosely bound and calcium phosphates in the plow horizon were estimated 33-35 mg/kg) and 16-18 mg/100 g, respectively. Under these concentrations, high and sustainable yields of spring wheat were obtained upon application of activated phosphorite.

  12. 33 CFR 142.33 - Foot protection.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 33 Navigation and Navigable Waters 2 2010-07-01 2010-07-01 false Foot protection. 142.33 Section... CONTINENTAL SHELF ACTIVITIES WORKPLACE SAFETY AND HEALTH Personal Protective Equipment § 142.33 Foot... for foot injury to occur shall wear footwear meeting the specifications of ANSI Z41, except...

  13. 33 CFR 142.33 - Foot protection.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 33 Navigation and Navigable Waters 2 2011-07-01 2011-07-01 false Foot protection. 142.33 Section... CONTINENTAL SHELF ACTIVITIES WORKPLACE SAFETY AND HEALTH Personal Protective Equipment § 142.33 Foot... for foot injury to occur shall wear footwear meeting the specifications of ANSI Z41, except...

  14. 33 CFR 142.33 - Foot protection.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 33 Navigation and Navigable Waters 2 2014-07-01 2014-07-01 false Foot protection. 142.33 Section... CONTINENTAL SHELF ACTIVITIES WORKPLACE SAFETY AND HEALTH Personal Protective Equipment § 142.33 Foot... for foot injury to occur shall wear footwear meeting the specifications of ANSI Z41, except...

  15. 33 CFR 142.33 - Foot protection.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 33 Navigation and Navigable Waters 2 2012-07-01 2012-07-01 false Foot protection. 142.33 Section... CONTINENTAL SHELF ACTIVITIES WORKPLACE SAFETY AND HEALTH Personal Protective Equipment § 142.33 Foot... for foot injury to occur shall wear footwear meeting the specifications of ANSI Z41, except...

  16. 33 CFR 142.33 - Foot protection.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 33 Navigation and Navigable Waters 2 2013-07-01 2013-07-01 false Foot protection. 142.33 Section... CONTINENTAL SHELF ACTIVITIES WORKPLACE SAFETY AND HEALTH Personal Protective Equipment § 142.33 Foot... for foot injury to occur shall wear footwear meeting the specifications of ANSI Z41, except...

  17. Measuring Water-Extractable Phosphorus in Manures to Predict Phosphorus Concentrations in Runoff

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Water-extractable phosphorus (WEP) in manures can influence the risk of P losses in runoff when manures are land applied. There is some uncertainty about how WEP in manures should be determined. Information on the effects of manure sample handling before analysis on WEP values and appropriate manu...

  18. Evaluation of Soil Phosphorus and Phosphorus in Water Discharged from Three Everglades Agricultural Area Farms

    E-print Network

    Ma, Lena

    Introduction/Literature Review 3 Objectives of Study 17 Approach/Methods 18 Results and Discussion 24 List statistics for three farms 48 Table 4 Descriptive statistics of monthly flow weighted TP (mg/l) on three EAA farms 49 Table 5 Descriptive statistics of monthly soil phosphorus (mg/kg) on three EAA farms 50 #12

  19. Mineralizable phosphorus, nitrogen, and carbon relationships in dairy manure at various carbon-to-phosphorus ratios

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Animal manure contains all major elements required for plant and microorganisms’ uptake and assimilation for growth, namely, phosphorus (P), nitrogen, and carbon. Information about interactions between transformations of nutrients and the turnover of P forms in dairy manure, is essential to accurat...

  20. DEVELOPMENT OF A PHOSPHORUS INDEX FOR PASTURES FERTILIZED WITH POULTRY LITTER - FACTORS AFFECTING PHOSPHORUS RUNOFF.

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Currently, several state and federal agencies are proposing upper limits on soil test phosphorus (P), above which animal manures can not be applied, based on the assumption that high P concentrations in runoff are due to high soil test P. Recent studies show that other factors are more indicative o...

  1. Effect of Microwave Treatment Upon Processing Oolitic High Phosphorus Iron Ore for Phosphorus Removal

    NASA Astrophysics Data System (ADS)

    Tang, Hui-Qing; Liu, Wei-Di; Zhang, Huan-Yu; Guo, Zhan-Cheng

    2014-10-01

    Influence of microwave treatment on the previously proposed phosphorus removal process of oolitic high phosphorus iron ore (gaseous reduction followed by melting separation) has been studied. Microwave treatment was carried out using a high-temperature microwave reactor (Model: MS-WH). Untreated ore fines and microwaved ore fines were then characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), and thermogravimetric analysis (TGA). Thereafter, experiments on the proposed phosphorus removal process were conducted to examine the effect of microwave treatment. Results show that microwave treatment could change the microstructure of the ore fines and has an intensification effect on its gaseous reduction by reducing gas internal resistance, increasing chemical reaction rate and postponing the occurrence of sintering. Results of gaseous reduction tests using tubular furnace indicate both microwave treatment and high reduction temperature high as 1273 K (1000 °C) are needed to totally break down the dense oolite and metallization rate of the ore fines treated using microwave power of 450 W could reach 90 pct under 1273 K (1000 °C) and for 2 hours. Results of melting separation tests of the reduced ore fines with a metallization rate of 90 pct show that, in addition to the melting conditions in our previous studies, introducing 3 pct Na2CO3 to the highly reduced ore fines is necessary, and metal recovery rate and phosphorus content of metal could reach 83 pct and 0.31 mass pct, respectively.

  2. Estimating Phosphorus Loss in Runoff from Manure and Fertilizer for a Phosphorus Loss Quantification Tool

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Non-point source pollution of fresh waters by phosphorus (P) is a concern because it contributes to accelerated eutrophication. Qualitative P Indexes that estimate the risk of field-scale P loss have been developed in the USA and Europe. However, given the state of the science concerning agricultura...

  3. Calcium effect on the metabolic pathway of phosphorus accumulating organisms in enhanced biological phosphorus removal systems.

    PubMed

    Zhang, Hai-Ling; Sheng, Guo-Ping; Fang, Wei; Wang, Yong-Peng; Fang, Cai-Yun; Shao, Li-Min; Yu, Han-Qing

    2015-11-01

    Phosphorus accumulating organisms (PAOs) have been found to act as glycogen-accumulating organisms (GAOs) under certain conditions, thus, the deterioration in the performance of enhanced biological phosphorus removal systems is not always attributed to the proliferation of GAOs. In this work, the effects of calcium on the metabolic pathway of PAOs were explored. It was found that when the influent Ca(2+) concentration was elevated, the tendency and extent of extracellular calcium phosphate precipitation increased, and the intracellular inert Ca-bound polyphosphate was synthesized, while the microbial population remained almost unchanged. The changes in the ratios of phosphorus released/acetate uptaken, the glycogen degraded/acetate uptaken and the poly-?-hydroxyalkanoates synthesized/acetate uptaken during the anaerobic period confirm that, as the influent Ca(2+) concentration was increased, the polyphosphate-accumulating metabolism was partially shifted to the glycogen-accumulating metabolism. At an influent Ca(2+) around 50 mg/L, in addition to the extracellular calcium phosphate precipitation, the intracellular inert Ca-bound polyphosphate synthesis might also be involved in the metabolic change of PAOs. The results of the present work would be beneficial to better understand the biochemical metabolism of PAOs in enhanced biological phosphorus removal systems. PMID:26233656

  4. Transformation of apatite phosphorus and non-apatite inorganic phosphorus during incineration of sewage sludge.

    PubMed

    Li, Rundong; Zhang, Ziheng; Li, Yanlong; Teng, Wenchao; Wang, Weiyun; Yang, Tianhua

    2015-12-01

    The recovery of phosphorus from incinerated sewage sludge ash (SSA) is assumed to be economical. Transformation from non-apatite inorganic phosphorus (NAIP) to apatite phosphorus (AP), which has a higher bioavailability and more extensive industrial applications, was studied at 750-950°C by sewage sludge incineration and model compound incineration with a calcium oxide (CaO) additive. Thermogravimetric differential scanning calorimetry analysis and X-ray diffraction measurements were used to analyze the reactions between NAIP with CaO and crystallized phases in SSA. High temperatures stimulated the volatilization of NAIP instead of AP. Sewage sludge incineration with CaO transformed NAIP into AP, and the percentage of AP from the total phosphorus reached 99% at 950°C. Aluminum phosphate reacted with CaO, forming Ca2P2O7 and Ca3(PO4)2 at 750-950°C. Reactions between iron phosphate and CaO occurred at lower temperatures, forming Ca(PO3)2 before reaching 850°C. PMID:26113414

  5. MODIFICATION OF PHOSPHORUS EXPORT FROM A CATCHMENT BY FLUVIAL SEDIMENT PHOSPHORUS INPUTS

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Phosphorus (P) export from agricultural watersheds can accelerate freshwater eutrophication. Landscape-based remedial measures can reduce edge-of-field P losses. However stream channel hydraulics and fluvial sediment properties can modify the forms and amounts of P exported by the time it reaches th...

  6. Phosphorus solubility of agricultural soils: a surface charge and phosphorus-31 NMR speciation study

    Technology Transfer Automated Retrieval System (TEKTRAN)

    We investigated ten soils from six states in United States to determine the relationship between potentiometric titration derived soil surface charge and Phosphorus-31 (P) nuclear magnetic resonance (NMR) speciation with the concentration of water-extractable P (WEP). The surface charge value at the...

  7. Phosphorus magnetic resonance spectroscopy studies in schizophrenia.

    PubMed

    Yuksel, Cagri; Tegin, Cuneyt; O'Connor, Lauren; Du, Fei; Ahat, Ezgi; Cohen, Bruce M; Ongur, Dost

    2015-09-01

    Phosphorus magnetic resonance spectroscopy ((31)P MRS) allows in vivo quantification of phosphorus metabolites that are considered to be related to membrane turnover and energy metabolism. In schizophrenia (SZ), (31)P MRS studies found several abnormalities in different brain regions suggesting that alterations in these pathways may be contributing to the pathophysiology. In this paper, we systematically reviewed the (31)P MRS studies in SZ published to date by taking patient characteristics, medication status and brain regions into account. Publications written in English were searched on http://www.ncbi.nlm.nih.gov/pubmed/, by using the keywords 'phosphomonoester', 'phosphodiester', 'ATP', 'phosphocreatine', 'phosphocholine', 'phosphoethanolamine','glycerophosphocholine', 'glycerophosphoethanolamine', 'pH', 'schizophrenia', and 'MRS'. Studies that measured (31)P metabolites in SZ patients were included. This search identified 52 studies. Reduced PME and elevated PDE reported in earlier studies were not replicated in several subsequent studies. One relatively consistent pattern was a decrease in PDE in chronic patients in the subcortical structures. There were no consistent patterns for the comparison of energy related phosphorus metabolites between patients and controls. Also, no consistent pattern emerged in studies seeking relationship between (31)P metabolites and antipsychotic use and other clinical variables. Despite emerging patterns, methodological heterogeneities and shortcomings in this literature likely obscure consistent patterns among studies. We conclude with recommendations to improve study designs and (31)P MRS methods in future studies. We also stress the significance of probing into the dynamic changes in energy metabolism, as this approach reveals abnormalities that are not visible to steady-state measurements. PMID:26228415

  8. MODELING PHOSPHORUS MOVEMENT FROM AGRICULTURE TO SURFACE WATERS

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Modeling phosphorus loss from agricultural watersheds is key to quantifying the long-term water quality benefits of alternative best management practices. Scientists engaged in this endeavor struggle to represent processes controlling phosphorus transport at scales and time frames that are meaningf...

  9. Chemical behavior of different species of phosphorus in coagulation.

    PubMed

    Park, Taejun; Ampunan, Vanvimol; Lee, Sanghyup; Chung, Eunhyea

    2016-02-01

    Phosphorus is one of the elements that have a significant impact on such environmental problems as eutrophication or algal bloom. Phosphorus compounds in water can be hydrolyzed to orthophosphate that is the only form of phosphorus that algae can assimilate. In this study, phosphorus removal in terms of orthophosphate and total phosphorus from wastewater was studied using alum or ferric ions as coagulants. It was observed that alum shows higher phosphorus removal efficiency than ferric ions in the same mole ratio concentrations. The proportion of orthophosphate among total phosphorus did not change significantly during coagulation process when the coagulant concentration is low. However, the proportion becomes gradually decreased as the coagulant concentration increases. Not only the electrolyte concentration difference in solution, but the characteristics of orthophosphate and polyphosphate such as reactivity and ionic size might also cause the differences in the removal rate. Orthophosphate that has greater reactivity than other phosphorus species would be involved in chemical reactions dominantly when large amounts of coagulants are applied. However, the effect of reactivity was diminished due to the large ionic size of polyphosphate and low concentration of electrolyte in low coagulant concentration during the coagulation process. PMID:26598995

  10. Soil, Water and Forage Testing Laboratory Phosphorus recommendations applicable for

    E-print Network

    by laboratory. Mehlich III by ICP only. Phosphorus Soil Fertility Recommendations for Oil Crops 0 5 10 15 20 25 PEANUTS , DRYLAND 65 60 55 45 40 30 25 20 10 5 0 PEANUTS , IRRIGATED 90 80 75 65 55 45 35 25 15 5 0 SESAME for methods used by laboratory. Mehlich III by ICP only. Phosphorus Soil Fertility Recommendations for Oil

  11. QUANTITATIVE DETERMINATION OF PHYTATE AND AVAILABLE PHOSPHORUS FOR MAIZE BREEDING

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Phytate is the dominant storage form of phosphorus (P) in mature cereal and oil grains. Phosphorus bound in phytate is nutritionally unavailable to monogastric animals and thus contributes to water pollution because it is excreted in the manure. Also, phytate can chelate certain minerals and exace...

  12. THE FATE AND TRANSPORT OF PHOSPHORUS IN AGRICULTURAL SYSTEMS

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Phosphorus (P) is an important input for economic crop and livestock production systems but excessive P losses from agricultural sources can accelerate eutrophication of surface waters. Phosphorus losses occur in particulate forms with eroded surface soil and in soluble forms in runoff and in some ...

  13. Environmental Benefits and Burdens of Phosphorus Recovery from Municipal Wastewater.

    PubMed

    Bradford-Hartke, Zenah; Lane, Joe; Lant, Paul; Leslie, Gregory

    2015-07-21

    The environmental benefits and burdens of phosphorus recovery in four centralized and two decentralized municipal wastewater systems were compared using life cycle assessment (LCA). In centralized systems, phosphorus recovered as struvite from the solids dewatering liquid resulted in an environmental benefit except for the terrestrial ecotoxicity and freshwater eutrophication impact categories, with power and chemical use offset by operational savings and avoided fertilizer production. Chemical-based phosphorus recovery, however, generally required more resources than were offset by avoided fertilizers, resulting in a net environmental burden. In decentralized systems, phosphorus recovery via urine source separation reduced the global warming and ozone depletion potentials but increased terrestrial ecotoxicity and salinization potentials due to application of untreated urine to land. Overall, mineral depletion and eutrophication are well-documented arguments for phosphorus recovery; however, phosphorus recovery does not necessarily present a net environmental benefit. While avoided fertilizer production does reduce potential impacts, phosphorus recovery does not necessarily offset the resources consumed in the process. LCA results indicate that selection of an appropriate phosphorus recovery method should consider both local conditions and other environmental impacts, including global warming, ozone depletion, toxicity, and salinization, in addition to eutrophication and mineral depletion impacts. PMID:26121005

  14. Reactive Phosphorus Removal from Aquaculture and Poultry Productions

    E-print Network

    Rubloff, Gary W.

    Reactive Phosphorus Removal from Aquaculture and Poultry Productions Systems Using Polymeric and poultry production wastewater effluents. The sorbent used was a cross-linked polyamine (PAA,HCl) polymeric poultry and aquaculture wastewater effluents. Upon treatment, phosphorus anion concentrations were reduced

  15. Reducing watershed scale phosphorus export through integrated management practices

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Phosphorus losses from golf course have been documented and are comparable to losses from agriculture and urban areas. Integrated management practices are required to address the problem. An integrated management approach using filter socks and limiting the amount of phosphorus applied to the golf c...

  16. Validation of a quantitative phosphorus loss assessment tool

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Pasture Phosphorus Management Plus (PPM Plus) is a tool that allows nutrient management and conservation planners to evaluate phosphorus loss from agricultural fields. This tool is a modified version of the widely used Soil and Water Assessment Tool (SWAT) model with a vastly simplified interface. ...

  17. Phosphorus recovery from pig manure solids prior to land application

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Land disposal of pig manure is an environmental concern due to an imbalance of the nitrogen to phosphorus (N:P) ratio for crop production, leading to excess phosphorus (P) in soils and potential risks of water pollution. A process called “quick wash” was investigated for its feasibility to extract ...

  18. Managing phosphorus for water quality protection - 10 principles

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The accelerated eutrophication of aquatic systems has primarily been the concern of developed nations where it represents the most pervasive impairment of surface water bodies. Managing phosphorus for water quality protection requires prudent tempering of agronomic emphases to build soil phosphorus,...

  19. Do Nutrient Limitation Patterns Shift from Nitrogen Toward Phosphorus

    E-print Network

    McNeil, Brenden

    Do Nutrient Limitation Patterns Shift from Nitrogen Toward Phosphorus with Increasing Nitrogen elements, such as phosphorus (P). Whether this shift is occur- ring relative to N deposition gradients nearly constant for most conifers and increasing only for black cherry and hemlock), but increased across

  20. 46 CFR 151.50-50 - Elemental phosphorus in water.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ...50-50 Elemental phosphorus in water. (a) Tanks shall be designed...design lading of phosphorus and its water blanket extended to 8 feet above...a single loading to the highest level to which the water blanket may rise, if that...

  1. 46 CFR 151.50-50 - Elemental phosphorus in water.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ...50-50 Elemental phosphorus in water. (a) Tanks shall be designed...design lading of phosphorus and its water blanket extended to 8 feet above...a single loading to the highest level to which the water blanket may rise, if that...

  2. 46 CFR 151.50-50 - Elemental phosphorus in water.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ...50-50 Elemental phosphorus in water. (a) Tanks shall be designed...design lading of phosphorus and its water blanket extended to 8 feet above...a single loading to the highest level to which the water blanket may rise, if that...

  3. 46 CFR 151.50-50 - Elemental phosphorus in water.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ...50-50 Elemental phosphorus in water. (a) Tanks shall be designed...design lading of phosphorus and its water blanket extended to 8 feet above...a single loading to the highest level to which the water blanket may rise, if that...

  4. 46 CFR 151.50-50 - Elemental phosphorus in water.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ...50-50 Elemental phosphorus in water. (a) Tanks shall be designed...design lading of phosphorus and its water blanket extended to 8 feet above...a single loading to the highest level to which the water blanket may rise, if that...

  5. 77 FR 46298 - Phosphorus Water Quality Standards for Florida Everglades

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-08-03

    ...FRL 9666-8] RIN 2040-AF38 Phosphorus Water Quality Standards for Florida Everglades...that identifies provisions of Florida's Water Quality Standards for Phosphorus in the...disapproved and that therefore are not applicable water quality standards for purposes of the...

  6. 76 FR 38592 - Phosphorus Water Quality Standards for Florida Everglades

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-07-01

    ...EPA-HQ-OW-2011-0515; FRL-9428-3] Phosphorus Water Quality Standards for Florida Everglades...would identify provisions of Florida's Water Quality Standards for Phosphorus in the...disapproved and that therefore are not applicable water quality standards for purposes of the...

  7. Soil phosphorus availability differences between sprinkler and furrow irrigation

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Water flowing in irrigation furrows detaches and transports soil particles and subsequently nutrients such as phosphorus. To reduce the risk of erosion and offsite phosphorus transport, producers in south-central Idaho have been converting from furrow to sprinkler irrigation. We completed research...

  8. The chemistry of phosphorus in dense interstellar clouds

    NASA Technical Reports Server (NTRS)

    Thorne, L. R.; Anicich, V. G.; Prasad, S. S.; Huntress, W. T., Jr.

    1984-01-01

    Laboratory experiments show that the ion-molecule chemistry of phosphorus is significantly different from that of nitrogen in dense interstellar clouds. The PH3 molecule is not readily formed by gas-phase, ion-molecule reactions in these regions. Laboratory results used in a simple kinetic model indicate that the most abundant molecule containing phosphorus in dense clouds is PO.

  9. Do invasive mussels restrict offshore phosphorus transport in Lake Huron?

    PubMed

    Cha, Yoonkyung; Stow, Craig A; Nalepa, Thomas F; Reckhow, Kenneth H

    2011-09-01

    Dreissenid mussels were first documented in the Laurentian Great Lakes in the late 1980s. Zebra mussels (Dreissena polymorpha) spread quickly into shallow, hard-substrate areas; quagga mussels (Dreissena rostriformis bugensis) spread more slowly and are currently colonizing deep, offshore areas. These mussels occur at high densities, filter large water volumes while feeding on suspended materials, and deposit particulate waste on the lake bottom. This filtering activity has been hypothesized to sequester tributary phosphorus in nearshore regions reducing offshore primary productivity. We used a mass balance model to estimate the phosphorus sedimentation rate in Saginaw Bay, a shallow embayment of Lake Huron, before and after the mussel invasion. Our results indicate that the proportion of tributary phosphorus retained in Saginaw Bay increased from approximately 46-70% when dreissenids appeared, reducing phosphorus export to the main body of Lake Huron. The combined effects of increased phosphorus retention and decreased phosphorus loading have caused an approximate 60% decrease in phosphorus export from Saginaw Bay to Lake Huron. Our results support the hypothesis that the ongoing decline of preyfish and secondary producers including diporeia (Diporeia spp.) in Lake Huron is a bottom-up phenomenon associated with decreased phosphorus availability in the offshore to support primary production. PMID:21812427

  10. Removal of vegetative clippings reduces dissolved phosphorus loss in runoff

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Phosphorus-containing sediment entering surface water may degrade water quality and promote eutrophication. Grass is sometimes planted as a vegetated filter strip buffer along vulnerable receiving water to trap sediment and reduce the severity of phosphorus nutrient loading. However, eutrophicatio...

  11. Modeling biogeochemical processes of phosphorus for global food supply.

    PubMed

    Dumas, Marion; Frossard, Emmanuel; Scholz, Roland W

    2011-08-01

    Harvests of crops, their trade and consumption, soil erosion, fertilization and recycling of organic waste generate fluxes of phosphorus in and out of the soil that continuously change the worldwide spatial distribution of total phosphorus in arable soils. Furthermore, due to variability in the properties of the virgin soils and the different histories of agricultural practices, on a planetary scale, the distribution of total soil phosphorus is very heterogeneous. There are two key relationships that determine how this distribution and its change over time affect crop yields. One is the relationship between total soil phosphorus and bioavailable soil phosphorus and the second is the relationship between bioavailable soil phosphorus and yields. Both of these depend on environmental variables such as soil properties and climate. We propose a model in which these relationships are described probabilistically and integrated with the dynamic feedbacks of P cycling in the human ecosystem. The model we propose is a first step towards evaluating the large-scale effects of different nutrient management scenarios. One application of particular interest is to evaluate the vulnerability of different regions to an increased scarcity in P mineral fertilizers. Another is to evaluate different regions' deficiency in total soil phosphorus compared with the level at which they could sustain their maximum potential yield without external mineral inputs of phosphorus but solely by recycling organic matter to close the nutrient cycle. PMID:21463882

  12. Solubility of manure phosphorus characterized by selective and sequential extractions

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The increasing awareness of the severity of the problem of phosphorus (P) derived from agricultural production moving off-farm and threatening water quality has led to the search for methods to characterize the forms and potential solubilities of phosphorus in food animal manures and manure products...

  13. Assessing the Long Term Impact of Phosphorus Fertilization on Phosphorus Loadings Using AnnAGNPS

    PubMed Central

    Yuan, Yongping; Bingner, Ronald L.; Locke, Martin A.; Stafford, Jim; Theurer, Fred D.

    2011-01-01

    High phosphorus (P) loss from agricultural fields has been an environmental concern because of potential water quality problems in streams and lakes. To better understand the process of P loss and evaluate the effects of different phosphorus fertilization rates on phosphorus losses, the USDA Annualized AGricultural Non-Point Source (AnnAGNPS) pollutant loading model was applied to the Ohio Upper Auglaize watershed, located in the southern portion of the Maumee River Basin. In this study, the AnnAGNPS model was calibrated using USGS monitored data; and then the effects of different phosphorus fertilization rates on phosphorus loadings were assessed. It was found that P loadings increase as fertilization rate increases, and long term higher P application would lead to much higher P loadings to the watershed outlet. The P loadings to the watershed outlet have a dramatic change after some time with higher P application rate. This dramatic change of P loading to the watershed outlet indicates that a “critical point” may exist in the soil at which soil P loss to water changes dramatically. Simulations with different initial soil P contents showed that the higher the initial soil P content is, the less time it takes to reach the “critical point” where P loadings to the watershed outlet increases dramatically. More research needs to be done to understand the processes involved in the transfer of P between the various stable, active and labile states in the soil to ensure that the model simulations are accurate. This finding may be useful in setting up future P application and management guidelines. PMID:21776225

  14. Determination of soil organic phosphorus exchange sensitivity

    NASA Astrophysics Data System (ADS)

    Shand, Charles; Wendler, Renate; Lumsdon, David; Cooper, Pat; George, Timothy; Brown, Lawrie; Giles, Courtney; Stutter, Marc; Menezes-Blackburn, Daniel; Zhang, Hao; Wearing, Catherine; Haygarth, Philip; Blackwell, Martin; Darch, Tegan

    2015-04-01

    Soils contain both organic and inorganic phosphorus (P) species in varying proportions. Studies have shown that many soils contain substantial amounts of inositol hexaphosphate (IHP) and there is much interest worldwide in developing strategies to make some use of this recalcitrant resource for plant growth to reduce P fertilizer inputs. Little is known about the preference of ion exchange processes in the solubilisation of organic vs inorganic P forms in soils, an important first step in making P forms bioavailable. Although they do not possess biotic functions, resins provides a simple means to deplete P forms in soil allowing investigation of exchange selectivity between inorganic and organic P forms. The aim of our work was to determine new understanding of exchange selectivity in soils and provide insight into potential depletion and plant uptake of soil phosphorus, with emphasis on organic forms such as IHP. For our study we used a Cambisol sampled from an agricultural area (Tayport) near Dundee in Scotland. The soil had a high Olsen (0.5 M sodium bicarbonate at pH 8.5) extractable P status (84 mg P/kg) and P-31 nuclear magnetic resonance analysis of its NaOH/EDTA extract showed it contained a substantial proportion of IHP (21 % of total extractable P). For resin extraction we used anion exchange resin sheets (4.17 cm each side) in bicarbonate form to minimise pH related solubilisation effects. We used 3.5 g of soil in 75 ml of water and added 1, 2 or 3 resin squares. After equilibration the resin squares were removed and replaced with fresh resin squares a further 3 times. Phosphorus was recovered from the resin sheets by elution with 0.25 M sulphuric acid and analysed by inductively coupled plasma spectroscopy to determine total P, and colorimetrically with malachite green to determine inorganic P with the remainder assigned to organic P. The data showed that the resin preferentially removed inorganic P and even after four sequential extractions little or no organic P (< 9 %) was found on the resin, despite the high charge density of IHP. The amount of total P extracted over the sequential extractions with 1, 2 or 3 resin squares decreased in an exponential manner. Keywords: anion exchange, inositol hexaphosphate, phosphorus, P-31 NMR, resin

  15. Magnetoelectronic properties of multilayer black phosphorus

    NASA Astrophysics Data System (ADS)

    Jiang, Yongjin; Roldán, Rafael; Guinea, Francisco; Low, Tony

    2015-08-01

    We examine the electronic properties of two-dimensional electron gas in black phosphorus multilayers in the presence of a perpendicular magnetic field, highlighting the role of in-plane anisotropy on various experimental quantities such as ac magnetoconductivity, screening, and magnetoplasmons. We find that resonant structures in the ac conductivity exhibits a redshift with increasing doping due to interband coupling ? . This arises from an extra correction term in the Landau energy spectrum proportional to n2?2 (n is Landau index), up to second order in ? . We found also that Coulomb interaction leads to highly anisotropic magnetoexcitons.

  16. Molecular phosphorus ion source for semiconductor technology

    SciTech Connect

    Gushenets V. I.; Hershcovitch A.; Bugaev, A.S.; Oks, E.M.; Kulevoy, T.V.

    2012-02-15

    This paper presents results on the generation of molecular phosphorus ion beams in a hot filament ion source. Solid red phosphorous is evaporated mainly as tetra-atomic molecules up to a temperature of 800 C. Thus, one of the main conditions for producing maximum P{sub 4}{sup +} fraction in the beam is to keep the temperature of the phosphorous oven, the steam line and the discharge chamber walls no greater than 800 C. The prior version of our ion source was equipped with a discharge chamber cooling system. The modified source ensured a P{sub 4}{sup +} ion beam current greater than 30% of the total beam current.

  17. Enhanced diffusion of phosphorus at grain boundaries

    NASA Technical Reports Server (NTRS)

    Cheng, L. J.; Shyu, C. M.; Stika, K. M.; Daud, T.; Crotty, G. T.

    1982-01-01

    Enhanced diffusion of phosphorus at grain boundaries in cast polycrystalline photovoltaic materials (Wacker, HEM, and Semix) was studied. It was found that the enhancements for the three materials were the same, indicating that the properties of boundaries are similar, even though they were grown by different techniques. In addition, it was observed that grain boundaries capable of enhancing the diffusion always have strong recombination activities. Both phenomena could be related to dangling bonds existing at the boundaries. The present study gives the first evidence that incoherent second order twins of 111/115-plane type are diffusion-active.

  18. Improving Phosphorus Availability in an Acid Soil Using Organic Amendments Produced from Agroindustrial Wastes

    PubMed Central

    Ch'ng, Huck Ywih; Ahmed, Osumanu Haruna; Majid, Nik Muhamad Ab.

    2014-01-01

    In acid soils, soluble inorganic phosphorus is fixed by aluminium and iron. To overcome this problem, acid soils are limed to fix aluminium and iron but this practice is not economical. The practice is also not environmentally friendly. This study was conducted to improve phosphorus availability using organic amendments (biochar and compost produced from chicken litter and pineapple leaves, resp.) to fix aluminium and iron instead of phosphorus. Amending soil with biochar or compost or a mixture of biochar and compost increased total phosphorus, available phosphorus, inorganic phosphorus fractions (soluble inorganic phosphorus, aluminium bound inorganic phosphorus, iron bound inorganic phosphorus, redundant soluble inorganic phosphorus, and calcium bound phosphorus), and organic phosphorus. This was possible because the organic amendments increased soil pH and reduced exchangeable acidity, exchangeable aluminium, and exchangeable iron. The findings suggest that the organic amendments altered soil chemical properties in a way that enhanced the availability of phosphorus in this study. The amendments effectively fixed aluminium and iron instead of phosphorus, thus rendering phosphorus available by keeping the inorganic phosphorus in a bioavailable labile phosphorus pool for a longer period compared with application of Triple Superphosphate without organic amendments. PMID:25032229

  19. Asymmetric capacitance and ambipolar metal insulator transition in black phosphorus

    NASA Astrophysics Data System (ADS)

    Saito, Yu; Iwasa, Yoshihiro

    2015-03-01

    Black phosphorus is a van der Waals type semiconducting layered material with a puckered honeycomb structure where each phosphorus atom is covalently bonded with three adjacent phosphorus atoms and has a direct band gap of 0.3 (bulk) - 2 (monolayer) depending on the number of layers, which can be promising material for optoelectronics devices such as photodetector. In this presentation, by using ionic liquid gating method, we report the ambipolar transistor operation and the field effect controlled ambipolar metal-insulator transition in black phosphorus thin flake. We observed a large modulation of the sheet resistance by more than 4 orders of magnitude in both electron channel and hole channel. These results suggest black phosphorus will be a key material for not only understanding physics of the conduction channel produced by ionic gating, but also potential functions including formation of p-n junction and therefore lateral tunnel diode utilizing intrinsic narrow band gap.

  20. Turnover of Phospholipids in Normal and Phosphorus-deficient Spirodela

    PubMed Central

    Bieleski, R. L.

    1972-01-01

    When 32P1 was supplied as a 15-minute pulse to normal Spirodela oligorrhiza plants, the first phospholipid to become fully labeled was phosphatidic acid. Phosphatidyl glycerol reached maximum labeling before the other major phospholipids. In phosphorus-deficient plants, however, phosphatidyl glycerol became labeled much more slowly than either phosphatidyl choline or phosphatidyl ethanolamine, and also the proportion of phosphatidyl glycerol present was smaller. Thus, phosphatidyl glycerol synthesis is sensitive to phosphorus deficiency. Since most of the phosphatidyl glycerol present in Spirodela was localized in the chloroplast, this effect appeared to be specifically one on chloroplast composition. The phosphorus-deficient chloroplast had a 60% lower phospholipid content and a normal phospholipid pattern, but the phospholipid which was present was apparently cycling much less rapidly. Zeatin, which ameliorates the visual symptoms of phosphorus deficiency, also reduces the effect of phosphorus deficiency on phospholipid synthesis. PMID:16658040

  1. Quantitation of phosphorus excretion in sheep by compartmental analysis

    SciTech Connect

    Schneider, K.M.; Boston, R.C.; Leaver, D.D.

    1987-04-01

    The control of phosphorus excretion in sheep has been examined by constructing a kinetic model that contains a mechanistic set of connections between blood and gastrointestinal tract. The model was developed using experimental data from chaff-fed sheep and gives an accurate description of the absorption and excretion of /sup 32/P phosphorus in feces and urine of the ruminating sheep. These results indicated the main control site for phosphorus excretion in the ruminating sheep was the gastrointestinal tract, whereas for the non-ruminating sheep fed the liquid diet, control was exerted by the kidney. A critical factor in the induction of adaptation of phosphorus reabsorption by the kidney was the reduction in salivation, and since this response occurred independently of marked changes in the delivery of phosphorus to the kidney, a humoral factor may be involved in this communication between salivary gland and kidney.

  2. Ultrathin Black Phosphorus Nanosheets for Efficient Singlet Oxygen Generation.

    PubMed

    Wang, Hui; Yang, Xianzhu; Shao, Wei; Chen, Shichuan; Xie, Junfeng; Zhang, Xiaodong; Wang, Jun; Xie, Yi

    2015-09-01

    Benefiting from its strong oxidizing properties, the singlet oxygen has garnered serious attentions in physical, chemical, as well as biological studies. However, the photosensitizers for the generation of singlet oxygen bear in low quantum yields, lack of long wavelength absorption band, poor biocompatibility, undegradable in living tissues, and so on. Here we first demonstrate the exfoliated black phosphorus nanosheets to be effective photosensitizers for the generation of singlet oxygen with a high quantum yield of about 0.91, rendering their attractive applications in catalysis and photodynamic therapy. Through in vitro and in vivo studies, the water dispersible black phosphorus nanosheets show notable cancer therapy ability. In addition, the photodegradable character of black phosphorus from element to biocompatible phosphorus oxides further highlights its therapeutic potential against cancer. This study will not only expand the breadth of study in black phosphorus but also offer an efficient catalyst and photodynamic therapy agent. PMID:26284535

  3. Transport properties of ultrathin black phosphorus on hexagonal boron nitride

    NASA Astrophysics Data System (ADS)

    Doganov, Rostislav A.; Koenig, Steven P.; Yeo, Yuting; Watanabe, Kenji; Taniguchi, Takashi; Özyilmaz, Barbaros

    2015-02-01

    Ultrathin black phosphorus, or phosphorene, is a two-dimensional material that allows both high carrier mobility and large on/off ratios. Similar to other atomic crystals, like graphene or layered transition metal dichalcogenides, the transport behavior of few-layer black phosphorus is expected to be affected by the underlying substrate. The properties of black phosphorus have so far been studied on the widely utilized SiO2 substrate. Here, we characterize few-layer black phosphorus field effect transistors on hexagonal boron nitride—an atomically smooth and charge trap-free substrate. We measure the temperature dependence of the field effect mobility for both holes and electrons and explain the observed behavior in terms of charged impurity limited transport. We find that in-situ vacuum annealing at 400 K removes the p-doping of few-layer black phosphorus on both boron nitride and SiO2 substrates and reduces the hysteresis at room temperature.

  4. Common Genetic Variants Associate with Serum Phosphorus Concentration

    PubMed Central

    Glazer, Nicole L.; Köttgen, Anna; Felix, Janine F.; Hwang, Shih-Jen; Liu, Yongmei; Lohman, Kurt; Kritchevsky, Stephen B.; Hausman, Dorothy B.; Petersen, Ann-Kristin; Gieger, Christian; Ried, Janina S.; Meitinger, Thomas; Strom, Tim M.; Wichmann, H. Erich; Campbell, Harry; Hayward, Caroline; Rudan, Igor; de Boer, Ian H.; Psaty, Bruce M.; Rice, Kenneth M.; Chen, Yii-Der Ida; Li, Man; Arking, Dan E.; Boerwinkle, Eric; Coresh, Josef; Yang, Qiong; Levy, Daniel; van Rooij, Frank J.A.; Dehghan, Abbas; Rivadeneira, Fernando; Uitterlinden, André G.; Hofman, Albert; van Duijn, Cornelia M.; Shlipak, Michael G.; Kao, W.H. Linda; Witteman, Jacqueline C.M.; Siscovick, David S.; Fox, Caroline S.

    2010-01-01

    Phosphorus is an essential mineral that maintains cellular energy and mineralizes the skeleton. Because complex actions of ion transporters and regulatory hormones regulate serum phosphorus concentrations, genetic variation may determine interindividual variation in phosphorus metabolism. Here, we report a comprehensive genome-wide association study of serum phosphorus concentration. We evaluated 16,264 participants of European ancestry from the Cardiovascular Heath Study, Atherosclerosis Risk in Communities Study, Framingham Offspring Study, and the Rotterdam Study. We excluded participants with an estimated GFR <45 ml/min per 1.73 m2 to focus on phosphorus metabolism under normal conditions. We imputed genotypes to approximately 2.5 million single-nucleotide polymorphisms in the HapMap and combined study-specific findings using meta-analysis. We tested top polymorphisms from discovery cohorts in a 5444-person replication sample. Polymorphisms in seven loci with minor allele frequencies 0.08 to 0.49 associate with serum phosphorus concentration (P = 3.5 × 10?16 to 3.6 × 10?7). Three loci were near genes encoding the kidney-specific type IIa sodium phosphate co-transporter (SLC34A1), the calcium-sensing receptor (CASR), and fibroblast growth factor 23 (FGF23), proteins that contribute to phosphorus metabolism. We also identified genes encoding phosphatases, kinases, and phosphodiesterases that have yet-undetermined roles in phosphorus homeostasis. In the replication sample, five of seven top polymorphisms associate with serum phosphorous concentrations (P < 0.05 for each). In conclusion, common genetic variants associate with serum phosphorus in the general population. Further study of the loci identified in this study may help elucidate mechanisms of phosphorus regulation. PMID:20558539

  5. Formation of stable phosphorus-carbon bond for enhanced performance in black phosphorus nanoparticle-graphite composite battery anodes.

    PubMed

    Sun, Jie; Zheng, Guangyuan; Lee, Hyun-Wook; Liu, Nian; Wang, Haotian; Yao, Hongbin; Yang, Wensheng; Cui, Yi

    2014-08-13

    High specific capacity battery electrode materials have attracted great research attention. Phosphorus as a low-cost abundant material has a high theoretical specific capacity of 2596 mAh/g with most of its capacity at the discharge potential range of 0.4-1.2 V, suitable as anodes. Although numerous research progress have shown other high capacity anodes such as Si, Ge, Sn, and SnO2, there are only a few studies on phosphorus anodes despite its high theoretical capacity. Successful applications of phosphorus anodes have been impeded by rapid capacity fading, mainly caused by large volume change (around 300%) upon lithiation and thus loss of electrical contact. Using the conducting allotrope of phosphorus, "black phosphorus" as starting materials, here we fabricated composites of black phosphorus nanoparticle-graphite by mechanochemical reaction in a high energy mechanical milling process. This process produces phosphorus-carbon bonds, which are stable during lithium insertion/extraction, maintaining excellent electrical connection between phosphorus and carbon. We demonstrated high initial discharge capacity of 2786 mAh·g(-1) at 0.2 C and an excellent cycle life of 100 cycles with 80% capacity retention. High specific discharge capacities are maintained at fast C rates (2270, 1750, 1500, and 1240 mAh·g(-1) at C/5, 1, 2, and 4.5 C, respectively). PMID:25019417

  6. Estimating source coefficients for phosphorus site indices.

    PubMed

    Elliott, H A; Brandt, R C; Kleinman, P J A; Sharpley, A N; Beegle, D B

    2006-01-01

    Phosphorus release to runoff varies widely for different land-applied organic P sources even when spread at equivalent total P rates. To address this variability, some P site indices include tabulated P source coefficients (PSCs) for differential weighting of applied P materials based on their runoff enrichment potential. Because runoff P can vary widely even within source categories depending on composition, storage, and treatment differences, this study explored a method for estimating PSCs based on the water-extractable P (WEP) content of the applied amendment. Using seven published rainfall-runoff studies that followed National Phosphorus Research Project protocols, runoff dissolved P (RDP) was correlated (r(2) = 0.80) with WEP for multiple surface-applied manures and biosolids. Assuming amendments with WEP >/= 10 g kg(-1) behave as highly soluble P sources and have a maximum PSC of 1.0, an empirical equation was developed for computing source-specific PSCs from laboratory-determined WEP values [PSC = 0.102 x WEP(0.99)]. For two independent runoff experiments, correlations between RDP loss and P source loading rate were improved when loading rates were multiplied by the computed (r(2) = 0.73-0.86) versus generic (r(2) = 0.45-0.48) PSCs. Source-specific PSCs should enhance the ability of assessment tools to identify vulnerable sites and P loss management alternatives, although the exact inclusion process depends on index scaling and conceptual framework. PMID:17071889

  7. Removing Phosphorus from Milkhouse Wastewater Using Vegetative Filter Strips

    NASA Astrophysics Data System (ADS)

    Geohring, L. D.; Kim, Y.; Steenhuis, T. S.

    2003-12-01

    Vegetative filter strips (VFS) are commonly used BMPs to control agricultural pollutants. In watersheds supplying drinking water to New York City, VFS are installed to remove phosphorus (P) from milkhouse wastewater and barnyard runoff to reduce P inputs to the drinking water reservoirs and minimize eutrophication. Monitoring wells were installed within two VFS and the application of chloride tracer was used to investigate flow paths and soluble reactive P (SRP) removal. The SRP concentrations in the wells were highest (generally over 10 mg/l) near the wastewater discharge point, while the Morgan's soil test P was high (over 60 mg/kg) in the downslope area of the VFS. Although P sorption isotherms indicate these soils (pH of 6.5) have high potential to remove P, the soil P accumulations were not occurring in the same area as the highest well water concentrations. Early chloride breakthroughs showed that milkhouse waste flowed preferentially in the VFS through locally saturated areas. The accelerated surface flow contributed to rapid transport of SRP in the wastewater to the downslope area of the VFS, resulting in less SRP removal. Although VFS of 33 to 40m long for the two sites, respectively, eventually reduced SRP to lower than 0.2mg/l in most cases, SRP was less effectively removed in areas where soil saturation occurred. The anaerobic condition of the locally saturated area apparently reduced opportunity for soil P sorption to Fe oxides in these sites. In order for the VFS to be more effective at P removal, efforts to distribute wastewater more uniformly to avoid soil saturation should be considered in new designs.

  8. SUMMARY REVIEW OF HEALTH EFFECTS ASSOCIATED WITH ELEMENTAL AND INORGANIC PHOSPHORUS COMPOUNDS: HEALTH ISSUE ASSESSMENT

    EPA Science Inventory

    Phosphorus is a nonmetallic essential element. lthough phosphorus occurs naturally in the environment, most of the phosphorus in the environment occurs during its manufacture into one of the three allotropic forms (white, red, or black) or into phosphorus compounds and during the...

  9. Semiconducting Layered Blue Phosphorus: A Computational Study Zhen Zhu and David Tomnek*

    E-print Network

    Tománek, David

    structure and high stability with the black phosphorus allotrope. We find the in-plane hexagonal structure. Unlike graphite and black phosphorus, blue phosphorus displays a wide fundamental band gap. Still study a likely transformation pathway from black to blue phosphorus and discuss possible ways

  10. Estimating phosphorus availability for microbial growth in an emerging landscape S.K. Schmidt a,

    E-print Network

    Colorado at Boulder, University of

    Estimating phosphorus availability for microbial growth in an emerging landscape S.K. Schmidt a Accepted 9 April 2011 Keywords: Biological weathering Phosphorus limitation Estimating phosphorus (P, based on microbial CO2 production kinetics and conserved carbon:phosphorus (C:P) ratios, to estimate

  11. Enhancing phosphorus removal in constructed wetlands with ochre from mine drainage treatment

    E-print Network

    Enhancing phosphorus removal in constructed wetlands with ochre from mine drainage treatment K for phosphorus (up to 26 mg kg21 ) means that it could be used in constructed wetlands to enhance phosphorus removal. Laboratory batch experiments showed that coarse-grained ochre removes 90% of all phosphorus forms

  12. Black phosphorus saturable absorber for ultrashort pulse generation

    NASA Astrophysics Data System (ADS)

    Sotor, J.; Sobon, G.; Macherzynski, W.; Paletko, P.; Abramski, K. M.

    2015-08-01

    Low-dimensional materials, due to their unique and versatile properties, are very interesting for numerous applications in electronics and optoelectronics. Recently rediscovered black phosphorus, with a graphite-like layered structure, can be effectively exfoliated up to the single atomic layer called phosphorene. Contrary to graphene, it possesses a direct band gap controllable by the number of stacked atomic layers. For those reasons, black phosphorus is now intensively investigated and can complement or replace graphene in various photonics and electronics applications. Here, we demonstrate that black phosphorus can serve as a broadband saturable absorber and can be used for ultrashort optical pulse generation. The mechanically exfoliated ˜300 nm thick layers of black phosphorus were transferred onto the fiber core, and under pulsed excitation at 1560 nm wavelength, its transmission increases by 4.6%. We have demonstrated that the saturable absorption of black phosphorus is polarization sensitive. The fabricated device was used to mode-lock an Er-doped fiber laser. The generated optical solitons with the 10.2 nm bandwidth and 272 fs duration were centered at 1550 nm. The obtained results unambiguously show that black phosphorus can be effectively used for ultrashort pulse generation with performances similar or even better than currently used graphene or carbon nanotubes. This application of black phosphorus proves its great potential to future practical use in photonics.

  13. Dietary phosphorus requirement of young abalone Haliotis discus Hannai Ino

    NASA Astrophysics Data System (ADS)

    Tan, Bei-Ping; Mai, Kang-Sen; Liufu, Zhi-Guo

    2002-03-01

    An experiment was performed to determine the dietary phosphorus requirement of the young abalone, Haliotis discus hannai. Five semi-purified diets were formulated to provide a series of graded levels of dietary total phosphorus (0.23% 1.98) from monobasic potassium phosphate (KH2P04). The brown alga, Laminaria japonica, was used as a control diet. Similar size abalone were distributed in a single-pass, flow-through system using a completely randomized design with six treatments and three replicates each treatment. The abalone were hand-fed to satiation with appropriate diets in excess, once daily at 17:00. The feeding trial was run for 120-d. Survival rate and soft-body to shell ratio (SB/S) were constantly maintained regardless of dietary treatment. However, the weight gain rate (WGR), daily increment in shell length (DISL), muscle RNA to DNA ratio (RNA/DNA), carcass levels of lipid and protein, soft-body alkaline phosphatase (SBAKP), and phosphorus concentrations of whole body (WB) and soft body (SB) were significantly (ANOVA, P<0.05) affected by the dietary phosphorus level. The dietary phosphorus requirements of the abalone were evaluated from the WGR, DISL, and RNA/DNA ratio respectively, by using second-order polynomial regression analysis. Based on these criteria, about 1.0% 1.2% total dietary phosphorus, i.e. 0.9% 1.1% dietary available phosphorus is recommended for the maximum growth of the abalone.

  14. Using phosphorus concentration in the soil solution to predict phosphorus desorption to water.

    PubMed

    Torrent, J; Delgado, A

    2001-01-01

    The growing concerns about water eutrophication have made it urgent to restrict losses of phosphorus (P) from agricultural soils and to develop methods for predicting such losses. In this work, we used the paradigm of P sorption-desorption curves to confirm the hypothesis that the amount of dissolved reactive phosphorus (DRP) released to a dilute electrolyte tends to be proportional to the concentration of DRP in the soil solution raised to a power that decreases with increasing solution to soil ratio (W). The hypothesis was tested for a group of 12 widely ranging European agricultural soils fertilized with P in excess of crop needs. Phosphorus desorption was studied under near-static and turbulent conditions in laboratory experiments. The concentration of DRP in the 1:1 soil to water extract (P1:1) was used as a proxy for the DRP concentration in the soil solution. The amount of desorbed P was found to be correlated with P1:1 raised to a power that decreased from 0.7 to 0.9 at W=100 to 0.2 to 0.4 at W=10 000. Correlation was not improved by introducing additional variables related to P sorption-desorption properties. Olsen P was found to be of lower predictive value than P1:1. Also, the index of degree of soil saturation with phosphorus (DSSP) based on oxalate extraction failed to predict P desorption. The fact that P1:1 seemingly predicts P desorption accurately for a wide range of soils makes it potentially useful in areas of high soil diversity. PMID:11577892

  15. Interaction between phosphorus removal and hybrid granular sludge formation under low hydraulic selection pressure at alternating anaerobic/aerobic conditions.

    PubMed

    Lang, Longqi; Wan, Junfeng; Zhang, Jing; Wang, Jie; Wang, Yan

    2015-11-01

    The hybrid granular sludge (HGS) formation and its performances on phosphorus removal were investigated in a sequencing batch airlift reactor. Under conditions of low superficial air velocity (SAV?=?0.68?cm?s(-1)) and relatively long settling time (15-30?min), aerobic granules appeared and coexisted with bio-flocs after 120 days operation. At the stable phase, 54% of total suspended solid (m/m) was granular sludge with the two typical sizes (Dmean?=?1.77?±?0.33 and 0.89?±?0.11?mm) in the reactor, where the settling velocity was 98.7?±?12.4 and 37.8?±?0.9?m?h(-1) for the big and small granules. With progressive extension of anaerobic time from 15 to 60 min before aerobic condition per cycle during the whole experiment, the HGS system can be maintained at a high total phosphorus removal efficiency (ca. 99%) since Day-270. The phosphorus content (wt %) in biomass was respectively 9.54?±?0.29, 7.60?±?0.48 and 6.15?±?0.59 for the big granules, small granules and flocs. PMID:25921951

  16. Molecular phosphorus ion source for semiconductor technology

    SciTech Connect

    Gushenets, V. I.; Bugaev, A. S.; Oks, E. M.; Hershcovitch, A.; Kulevoy, T. V.

    2012-02-15

    This paper presents results on the generation of molecular phosphorus ion beams in a hot filament ion source. Solid red phosphorous is evaporated mainly as tetra-atomic molecules up to a temperature of 800 deg. C. Thus, one of the main conditions for producing maximum P{sub 4}{sup +} fraction in the beam is to keep the temperature of the phosphorous oven, the steam line and the discharge chamber walls no greater than 800 deg. C. The prior version of our ion source was equipped with a discharge chamber cooling system. The modified source ensured a P{sub 4}{sup +} ion beam current greater than 30% of the total beam current.

  17. Nonequilibrium spin injection in monolayer black phosphorus.

    PubMed

    Chen, Mingyan; Yu, Zhizhou; Wang, Yin; Xie, Yiqun; Wang, Jian; Guo, Hong

    2016-01-21

    Monolayer black phosphorus (MBP) is an interesting emerging electronic material with a direct band gap and relatively high carrier mobility. In this work we report a theoretical investigation of nonequilibrium spin injection and spin-polarized quantum transport in MBP from ferromagnetic Ni contacts, in two-dimensional magnetic tunneling structures. We investigate physical properties such as the spin injection efficiency, the tunnel magnetoresistance ratio, spin-polarized currents, charge currents and transmission coefficients as a function of external bias voltage, for two different device contact structures where MBP is contacted by Ni(111) and by Ni(100). While both structures are predicted to give respectable spin-polarized quantum transport, the Ni(100)/MBP/Ni(100) trilayer has the superior properties where the spin injection and magnetoresistance ratio maintains almost a constant value against the bias voltage. The nonequilibrium quantum transport phenomenon is understood by analyzing the transmission spectrum at nonequilibrium. PMID:26675820

  18. Plasmonics in strained monolayer black phosphorus

    NASA Astrophysics Data System (ADS)

    Lam, Kai-Tak; Guo, Jing

    2015-03-01

    Monolayer black phosphorus (BP) has high band anisotropy which can be modulated with strain. We show that the plasmonic dispersions in monolayer BPs not only strongly depend on the crystalline direction but also strain. Application of strain can alter the optimum direction for plasmon transport and engineer the anisotropic plasmonic dispersion relations. Furthermore, we evaluate the plasmon losses and wave localization via the random-phase approximation framework. It is found that although the BP monolayer is inferior to graphene in terms of loss at the same wave localization, it outperforms monolayer MoS2. The dependence of plasmon properties on the applied strain in BP makes it an interesting nanophotonic material, as well as a potential medium for piezo-optic applications.

  19. A radio search for interstellar phosphorus compounds

    NASA Technical Reports Server (NTRS)

    Hollis, J. M.; Snyder, L. E.; Lovas, F. J.; Ulich, B. L.

    1980-01-01

    The J = 1-0 and 3-2 transitions of phosphorus nitride, PN, with resolvable hyperfine components at 46.99 GHz and blended components at 140.97 GHz, and transitions of phosphine, PH3, at 47.39 and 46.94 GHz, arising from a small induced dipole moment, have been searched for but not found in interstellar molecular clouds. The J = 3/2-1/2, F - 3/2-3/2 transition of nitric oxide, NO, and the J(K-K+) = 16(4, 12) -15(5, 11) transition of sulfur dioxide, SO2, have been detected in Orion and Sagittarius B2. An unidentified emission line, U140921.8 MHz, has been observed in IRC + 10216.

  20. Biological phosphorus cycling in dryland regions

    USGS Publications Warehouse

    Belnap, Jayne

    2011-01-01

    The relatively few studies done on phosphorus (P) cycling in arid and semiarid lands (drylands) show many factors that distinguish P cycling in drylands from that in more mesic regions. In drylands, most biologically relevant P inputs and losses are from the deposition and loss of dust. Horizontal and vertical redistribution of P is an important process. P is concentrated at the soil surface and thus vulnerable to loss via erosion. High pH and CaCO3 limit P bioavailability, and low rainfall limits microbe and plant ability to free abiotically bound P via exudates, thus making it available for uptake. Many invasive plants are able to access recalcitrant P more effectively than are native plants. As P availability depends on soil moisture and temperature, climate change is expected to have large impacts on P cycling

  1. Organic Phosphorus in the Deep Subseafloor Environment

    NASA Astrophysics Data System (ADS)

    Defforey, D.; Paytan, A.

    2014-12-01

    Phosphorus (P) is a macronutrient involved both in functional and structural components of all living cells. This makes it an essential nutrient for life, including microbial life in the deep subseafloor habitat. P availability in this environment is limited since organic matter is scarce and P is thought to be mainly present in refractory mineral phases. However, recent estimates suggest that the deep biosphere may contain up to 1% of Earth's total biomass, which implies that microorganisms may possess mechanisms to harvest recalcitrant phosphorus compounds in this environment. In addition, the role of the organic P pool in this setting is poorly understood and could be of great importance should it represent an important P pool fueling the deep biosphere. This study aims to identify and quantify organic P compounds in open ocean sediments using our newly developed sequential extraction procedure for 31P nuclear magnetic resonance spectroscopy (31P NMR). This method amplifies the signal of organic P in spectra by increasing its concentration and quantitatively removing the majority of inorganic P. Briefly, P bound to iron oxyhydroxides is removed from sediment samples during a reductive step; then, P in authigenic and biogenic apatite is solubilized over the course of an extraction in an acidic buffer. These two steps remove the majority of inorganic P from the sample. Lastly, the residue is extracted in 0.25M NaOH+ 0.05M Na2EDTA and the supernatant is frozen and lyophilized prior to 31P NMR analysis. This method will be applied to sediment samples from North Pond (IODP expedition 336), an isolated sediment pond on the western flank of the Mid-Atlantic ridge. This work will provide valuable insight into the diagenetic processes affecting organic P in open ocean sediments and into possible nutrient sources to the deep biosphere.

  2. Irreversible phosphorus sorption in septic system plumes?

    PubMed

    Robertson, W D

    2008-01-01

    The mobility of phosphorus (P) in septic system plumes remains a topic of debate because of the considerable reactivity of this constituent. In this study, a septic system plume in Ontario was monitored over a 16-year period with detail that clearly shows the advancing frontal portion of the P plume. This monitoring record provides insight into the extent of secondary P attenuation in the ground water zone beyond that available from previous studies. A P plume 16 m in length developed over the monitoring period with PO(4)-P concentrations (3 to 6 mg/L) that approached the concentrations present under the tile bed. Simulations using an analytical model showed that when first-order solute decay was considered to account for the possibility of secondary P attenuation in the ground water zone, field values could only be matched when decay was absent or occurred at an exceedingly slow rate (half-life greater than 30 years). Thus, hypothesized secondary P attenuation mechanisms such as slow recystallization of sorbed P into insoluble metal phosphate minerals, diffusion into microsites, or kinetically slow direct precipitation of P minerals such as hydroxyapatite were inactive in the ground water zone at this site or occurred at rates that were too slow to be observed in the context of the current 16-year study. Desorption tests on sediment samples from below the tile bed indicated a PO(4) distribution coefficient (K(d)) of 4.8, which implies a P retardation factor of 25, similar to the field apparent value of 37 determined from model calibrations. This example of inactive secondary P attenuation in the ground water zone shows that phosphorus in some ground water plumes can remain mobile and conservative for decades. This has important implications for septic systems located in lakeshore environments when long-term usage scenarios are considered. PMID:18181864

  3. Agricultural trade and the global phosphorus cycle

    NASA Astrophysics Data System (ADS)

    Schipanski, M.; Bennett, E.; Riskin, S.; Porder, S.

    2012-12-01

    Trends of increasing agricultural trade, increased concentration of livestock production systems, and increased human consumption of livestock products influence the distribution of nutrients across the global landscape. Phosphorus (P) represents a unique management challenge as we are rapidly depleting mineable reserves of this essential and non-renewable resource. At the same time, its overuse can lead to pollution of aquatic ecosystems. We analyzed the relative contributions of food crop, feed crop, and livestock product trade to P flows through agricultural soils for twelve countries from 1961 to 2007. We then used case studies of P fertilizer use in the world's three major soybean export regions: Iowa (USA), Mato Grosso (Brazil), and Buenos Aires (Argentina) to examine the influence of historical P management and soil types on agriculture's environmental consequences. Due to the intensification of agricultural production, average soil surface P balances more than tripled from 6 to 21 kg P per ha between 1961 and 2007 for the twelve study countries. Consequently, countries that are primarily agricultural exporters carried increased risks for water pollution or, for Argentina, reduced soil fertility due to soil P mining to support exports. In 2007, nations imported food and feed from regions with higher apparent P fertilizer use efficiencies than if those crops were produced domestically. However, this was largely because imports were sourced from regions depleting soil P resources to support export crop production. In addition, the pattern of regional specialization and intensification of production systems also reduced the potential to recycle P resources, with greater implications for livestock production than crop production. In a globalizing world, it will be increasingly important to integrate biophysical constraints of our natural resources and environmental impacts of agricultural systems into trade policy and agreements and to develop mechanisms that move us closer to more equitable management of non-renewable resources such as phosphorus.

  4. Plant uptake of phosphorus and nitrogen recycled from synthetic source-separated urine.

    PubMed

    Bonvin, Christophe; Etter, Bastian; Udert, Kai M; Frossard, Emmanuel; Nanzer, Simone; Tamburini, Federica; Oberson, Astrid

    2015-03-01

    Urine contains about 50 % of the phosphorus (P) and about 90 % of the nitrogen (N) excreted by humans and is therefore an interesting substrate for nutrient recovery. Source-separated urine can be used to precipitate struvite or, through a newly developed technology, nitrified urine fertilizer (NUF). In this study, we prepared (33)P radioisotope- and stable (15)N isotope-labeled synthetic NUF (SNUF) and struvite using synthetic urine and determined P and N uptake by greenhouse-grown ryegrass (Lolium multiflorum var. Gemini) fertilized with these products. The P and N in the urine-based fertilizers were as readily plant-available in a slightly acidic soil as the P and N in reference mineral fertilizers. The ryegrass crop recovered 26 % of P applied with both urine-based fertilizers and 72 and 75 % of N applied as struvite and SNUF, respectively. Thus, NUF and urine-derived struvite are valuable N and P recycling fertilizers. PMID:25681979

  5. Determination of clemastine in human plasma by gas chromatography with nitrogen-phosphorus detection.

    PubMed

    Davydova, N N; Yasuda, S U; Woosley, R L; Wainer, I W

    2000-07-01

    A method for the quantitative determination of clemastine in human plasma has been developed and validated. The assay uses gas chromatography with nitrogen-phosphorus detection and a HP-1 capillary column (25 mx0.22 mm, film thickness 0.33 mm) coated with dimethylpolysiloxane. Clemastine (with orphenadrine as internal standard) was isolated from human plasma using liquid-liquid extraction. A linear relationship was observed between 0.1 and 12.8 ng/ml using the peak area ratio of clemastine to orphenadrine with a correlation coefficient greater than 0.99 (the detection limit for clemastine was 0.06 ng/ml). The intra- and inter-day coefficients of variation were less than 11%. The developed method was used for the analysis of plasma samples from healthy volunteers (n = 19) to examine the pharmacokinetics of the antihistamine clemastine after single and multiple oral doses of clemastine fumarate. PMID:10985579

  6. Key structure-activity relationships in the vanadium phosphorus oxide catalyst system

    SciTech Connect

    Thompson, M.R. ); Ebner, J.R. )

    1990-04-01

    The crystal structure of vanadyl pyrophosphate has been redetermined using single crystals obtained from a near solidified melt of a microcrystalline catalyst sample. Crystals that index as vanadyl pyrophosphate obtained from this melt are variable in color. Crystallographic refinement of the single crystal x-ray diffraction data indicates that structural differences among these materials can be described in terms of crystal defects associated with linear disorder of the vanadium atoms. The importance of the disorder is outlined in the context of its effect on the proposed surface topology parallel to (1,0,0). Models of the surface topology simply and intuitively account for the non-stoichometric surface atomic P/V ratio exhibited by selective catalysts of this phase. These models also point to the possible role of the excess phosphorus in providing site isolation of reactive centers at the surface. 33 refs., 7 figs.

  7. Influence of Antecedent Hydrologic Conditions on Nitrate and Phosphorus Export from a Small Agricultural Catchment in Southern Ontario, Canada

    NASA Astrophysics Data System (ADS)

    Macrae, M. L.; English, M. C.; Schiff, S. L.; Stone, M.

    2009-04-01

    The ability of the scientific community to quantify and predict discharge and nutrient transport in a range of settings is confounded by the effects of antecedent hydrologic conditions in upland areas. Previous work has empirically linked spatial variables such as land use, soil type, topography, and drainage characteristics to hydrochemical export from various landscapes (e.g. MCDOWELL et al., 2001; ARHEIMER and LIDEN, 2000; STAMM et al., 1998; JORDAN et al., 1997; WELSCH et al., 2001). However, the specific reasons why similar types of events produce different nutrient export patterns are poorly understood. Nutrient (nitrate, soluble and total phosphorus) transport from agricultural catchments is difficult to quantify and predict because of the influence of variable hydrologic flowpaths and their interaction with varying nutrient pools. This research examines the role of antecedent hydrologic conditions on stream discharge and nitrate (NO3-), soluble reactive phosphorus (SRP) and total phosphorus (TP) export from a small (2.7 km2) first-order agricultural catchment in Southern Ontario, Canada. During 59 events occurring over a two-year sampling period (year-round), runoff ratios ranged from 0-0.99). Runoff ratios increased throughout successive events as conditions became wetter although key indices of antecedent wetness such as water table position, pre-event streamflow and soil moisture did not yield predictive relationships. Nitrate, SRP and TP transport from the catchment increased with antecedent wetness during some periods but decreased with antecedent wetness during other periods. This variability appears to be linked to a combination of the position of water table before and during the event, as well as timing of fertilizer application. It is hypothesized that in general, wetter antecedent hydrologic conditions increase nutrient transport from the catchment by increasing macropore connectivity between surface soil horizons and tile drains, although this is not always the case. Arheimer, B and R Liden (2000) Nitrogen and phosphorus concentrations from agricultural catchments - influence of spatial and temporal variables. J. Hydrology 227: 140-159. Jordan TE, DL Correll, and DE Weller (1997) Relating nutrient discharges from watersheds to land use and streamflow variability. Water Resources Res. 33: 2579-2590. McDowell RW, AN Sharpley, LM Condron, PM Haygarth, and PC Brookes (2001) Processes controlling soil phosphorus release to runoff and implications for agricultural management. Nutrient Cycling in Agroecosystems 59: 269-284. Stamm C, H Fluhler, R Gachter, J Leuenberger, and H Wunderli (1998) Preferential transport of phosphorus in drained grassland soils. J. Environ. Qual. 27: 515-522. Welsch DL, CN Kroll, JJ McDonnell, and DA Burns (2001) Topographic controls on the chemistry of subsurface stormflow: Hydrological Processes 15: 1925-1938.

  8. Phosphorus adsorption and desorption properties of lunar simulants 

    E-print Network

    Sutter, Brad

    1995-01-01

    efficient phosphorus (P) fertilizer rate that would provide optimal crop growth in Minnesota Basalt Lunar Simulant (MBLS) and Lunar Glass Simulant (LGS). To achieve this objective, simulant P adsorption, desorption and kinetic desorption Q/I relationships...

  9. Analysis of reduced phosphorus in samples of environmental interest.

    PubMed

    Morton, Siyuan C; Glindemann, Dietmar; Wang, Xiaorong; Niu, Xiaojun; Edwards, Marc

    2005-06-15

    The combination of ion chromatography (IC) and inductively coupled plasma emission spectroscopy (ICP-ES) was used forthe sensitive and specific detection of hypophosphite (PO2), phosphite (PO3), methylphosphonic acid (MPA), and phosphate (PO4). Application of this technique to a wide range of environmental samples proved that reduced phosphorus was present in some situations including process water from thermal phosphorus plants, drinking water contacting cast iron, and phosphorus corrosion inhibitor used in water treatment and in sewage wastewater. Preliminary testing did not detect high concentrations of reduced phosphorus and phosphine in situations where it was previously reported to be very important, including anaerobic digesters in wastewater treatment plants. The new IC-ICP-ES technique is a promising tool for use in corrosion and soil research where phosphites are likely to be present. PMID:16047769

  10. 21 CFR 862.1580 - Phosphorus (inorganic) test system.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ...AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES CLINICAL CHEMISTRY AND CLINICAL TOXICOLOGY DEVICES Clinical Chemistry Test Systems § 862.1580 Phosphorus (inorganic) test system....

  11. Method of removing and detoxifying a phosphorus-based substance

    DOEpatents

    Vandegrift, George F. (Bolingbrook, IL); Steindler, Martin J. (Park Forest, IL)

    1989-01-01

    A method of removing organic phosphorus-based poisonous substances from water contaminated therewith and of subsequently destroying the toxicity of the substance is disclosed. Initially, a water-immiscible organic is immobilized on a supported liquid membrane. Thereafter, the contaminated water is contacted with one side of the supported liquid membrane to selectively dissolve the phosphorus-based substance in the organic extractant. At the same time, the other side of the supported liquid membrane is contacted with a hydroxy-affording strong base to react the phosphorus-based substance dissolved by the organic extractant with a hydroxy ion. This forms a non-toxic reaction product in the base. The organic extractant can be a water-insoluble trialkyl amine, such as trilauryl amine. The phosphorus-based substance can be phosphoryl or a thiophosphoryl.

  12. Eutrophication of aquatic ecosystems: Bistability and soil phosphorus

    PubMed Central

    Carpenter, Stephen R.

    2005-01-01

    Eutrophication (the overenrichment of aquatic ecosystems with nutrients leading to algal blooms and anoxic events) is a persistent condition of surface waters and a widespread environmental problem. Some lakes have recovered after sources of nutrients were reduced. In others, recycling of phosphorus from sediments enriched by years of high nutrient inputs causes lakes to remain eutrophic even after external inputs of phosphorus are decreased. Slow flux of phosphorus from overfertilized soils may be even more important for maintaining eutrophication of lakes in agricultural regions. This type of eutrophication is not reversible unless there are substantial changes in soil management. Technologies for rapidly reducing phosphorus content of overenriched soils, or reducing erosion rates, are needed to improve water quality. PMID:15972805

  13. Community-level consequences of mycorrhizae depend on phosphorus availability

    E-print Network

    Collins, Cathy Diane; Foster, Bryan L.

    2009-09-01

    -mycotrophic species. To test these predictions, we manipulated phosphorus to create a soil nutrient gradient for mesocosm communities composed of native prairie grasses and then compared community properties for mesocosms with and without AMF. We found that, where P...

  14. Phosphorus Radicals DOI: 10.1002/anie.200700059

    E-print Network

    Müller, Peter

    ] radicals have been isolated. Yet the synthesis of a neutral phosphorus radical that exists as a monomer-Cl, which can be effected by a variety of reducing agents. One such reductant, the potent chlorine

  15. Phosphorus Determination by Derivative Activation Analysis: A Multifaceted Radiochemical Application.

    ERIC Educational Resources Information Center

    Kleppinger, E. W.; And Others

    1984-01-01

    Although determination of phosphorus is important in biology, physiology, and environmental science, traditional gravimetric and colorimetric methods are cumbersome and lack the requisite sensitivity. Therefore, a derivative activation analysis method is suggested. Background information, procedures, and results are provided. (JN)

  16. A quantitative phosphorus loss assessment tool for agricultural fields

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Conservation and nutrient management planners need an assessment tool to accurately predict phosphorus (P) loss from agricultural lands. Available tools are either qualitative indices with limited capability to quantify offsite water quality impacts or prohibitively complex quantitative process-bas...

  17. The Phosphorus Compounds of Cotton Seed Meal and Wheat Bran. 

    E-print Network

    Rather, J. B. (James Burness)

    1913-01-01

    claimed, and especially that cottonseed meal does not contain meta- or pyrophos- phoric acid. The work presented in this bulletin is a continuation of the above study of the forms of phosphorus compounds in cottonseed mea], together... with an investigation of the acid-soluble phosphorus com? pounds of wheat bran. REVIEW OF LITERATURE. Hardin states (Bulletin 8, Dew series. South Carolina ExperimeDt Sta? tion) that cottonseed meal consists largely of meta- and pyrophosphoric acids. Crawford (Jour...

  18. Electrodeposition of amorphous ternary nickel-chromium-phosphorus alloy

    DOEpatents

    Guilinger, Terry R. (Albuquerque, NM)

    1990-01-01

    Amorphous ternary nickel-chromium-phosphorus alloys are electrodeposited from a bath comprising a nickel salt, a chromium salt, a phosphorus source such as sodium hypophosphite, a complexing agent for the nickel ions, supporting salts to increase conductivity, and a buffering agent. The process is carried out at about room temperature and requires a current density between about 20 to 40 A/dm.sup.2.

  19. Phosphorus flows and balances of the European Union Member States.

    PubMed

    van Dijk, Kimo C; Lesschen, Jan Peter; Oenema, Oene

    2016-01-15

    Global society faces serious "phosphorus challenges" given the scarcity, essentiality, unequal global distribution and, at the same time, regional excess of phosphorus (P). Phosphorus flow studies can be used to analyze these challenges, providing insight into how society (re)uses and loses phosphorus, identifying potential solutions. Phosphorus flows were analyzed in detail for EU-27 and its Member States. To quantify food system and non-food flows, country specific data and historical context were considered. The sectors covered were crop production (CP), animal production (AP), food processing (FP), non-food production (NF) and consumption (HC). The results show that the EU-27 imported 2392GgP in 2005, half of which accumulated in agricultural soils (924Gg) and half was lost as waste (1217Gg). Net accumulation was 4.9kgP/ha/year ranging between +23.2 (Belgium) and -2.8 (Slovakia). From the system losses, 54% was lost from HC in diverse waste flows and 28% from FP, mainly through incinerated slaughter residues. The largest HC losses (655Gg) were wastewater (55%), food waste (27%), and pet excreta (11%). Phosphorus recycling rates were 73% in AP, 29% in FP, 21% in HC and ~0% in NF. The phosphorus use efficiencies showed that, relative to sector input, about 70% was taken up by crops (CP), 24% was retained in animals (AP), 52% was contained in food products (FP), 76% was stored in non-food materials (NF), and 21% was recycled (HC). Although wide-ranging variation between countries, generally phosphorus use in EU-27 was characterized by relatively (1) large dependency on (primary) imports, (2) long-term accumulation in agricultural soils, especially in west European countries, (3) leaky losses throughout entire society, especially emissions to the environment and sequestered waste, (4) little recycling with the exception of manure, and (5) low use efficiencies, because of aforementioned issues, providing ample opportunities for improvement. PMID:26421756

  20. Calcium and phosphorus requirements of bobwhite quail chicks

    USGS Publications Warehouse

    Nestler, R.B.; DeWitt, J.B.; Derby, J.V.; Moschler, M.

    1948-01-01

    Four experiments involving 873 bob-white quail (Colinus virginianus) chicks were conducted at the Patuxent Research Refuge, Laurel, Maryland. A comparison was made of calcium: phosphorus ratios of 1:1, 15:1, 1%: 1, 2:1, 2+:1,and 2%: 1in diets with phosphorus levels of 0.52, 0.75, 1.00, and 1.25 percent. The results indicate that the optimum level of phosphorus for growth is in the neighborhood of 0.75 per cent, and that of calcium is about 1.00 per cent, making a ratio of 1 1/3: 1....Although the greatest efficiency of feed utilization occurred on the phosphorus level of 0.52 per cent, the liveweight and bone-ash of the birds at the end of ten weeks were significantly lower than they were on the levels of 0.75 and 1.00 per cent, phosphorus. Bone-ash of birds on a Ca: P ratio of 1:1was significantly lower than that on any of the other five ratios, regardless of phosphorus level....There was a significant reverse correlation between the Ca: P ratio of the diet and the storage of vitamin A in the liver. Storage was especially low on the ratio of 2 2/3: 1....The low and high levels of calcium and phosphorus considered in these studies are abnormal, the low level especially being hard to obtain with common feedstuffs, if the protein requirements of the birds are met. Nevertheless, even on such levels, results were not disastrous. The growth of quail in the wild happens during a season when the birds have access to the minerals of the soil and in the abundant animal matter (mostly insects), as well as to minerals in plant material. Therefore, seemingly, calcium and phosphorus need not be critical nutrients for growing quail in the wild.

  1. Phosphorus out-diffusion in laser molten silicon

    NASA Astrophysics Data System (ADS)

    Köhler, J. R.; Eisele, S. J.

    2015-04-01

    Laser doping via liquid phase diffusion enables the formation of defect free pn junctions and a tailoring of diffusion profiles by varying the laser pulse energy density and the overlap of laser pulses. We irradiate phosphorus diffused 100 oriented p-type float zone silicon wafers with a 5 ?m wide line focused 6.5 ns pulsed frequency doubled Nd:YVO4 laser beam, using a pulse to pulse overlap of 40%. By varying the number of laser scans Ns = 1, 2, 5, 10, 20, 40 at constant pulse energy density H = 1.3 J/cm2 and H = 0.79 J/cm2 we examine the out-diffusion of phosphorus atoms performing secondary ion mass spectroscopy concentration measurements. Phosphorus doping profiles are calculated by using a numerical simulation tool. The tool models laser induced melting and re-solidification of silicon as well as the out-diffusion of phosphorus atoms in liquid silicon during laser irradiation. We investigate the observed out-diffusion process by comparing simulations with experimental concentration measurements. The result is a pulse energy density independent phosphorus out-diffusion velocity vout = 9 ± 1 cm/s in liquid silicon, a partition coefficient of phosphorus 1 < kp < 1.1 and a diffusion coefficient D = 1.4(±0.2)cm2/s × 10-3 × exp[-183 meV/(kBT)].

  2. Phosphorus cycling in the deep subseafloor biosphere at North Pond

    NASA Astrophysics Data System (ADS)

    Defforey, D.; Paytan, A.

    2013-12-01

    Phosphorus is a macronutrient involved both in functional and structural components of all living cells. This makes it an essential nutrient for life, including microbial life in the deep subseafloor habitat. Phosphorus availability in this environment is limited since it is thought to be mainly present in refractory mineral phases. However, recent estimates suggest that the deep biosphere may contain up to 1% of Earth's total biomass, which implies that microorganisms may possess mechanisms to harvest recalcitrant phosphorus compounds in this environment. This study sheds light on those mechanisms by investigating phosphorus cycling in deep open-ocean sediments using stable oxygen isotope ratios in phosphate. Furthermore, this study provides insight into changes in phosphorus bioavailability and mobility under a range of natural environmental conditions within the deep biosphere. Sediment samples were collected from four boreholes drilled during the IODP Expedition 336 to North Pond, an isolated sediment pond on the western flank of the Mid-Atlantic Ridge. Sedimentary phosphorus compounds are characterized using sequential extractions (SEDEX), which separate them into five distinct pools. Phosphate from the various extracts are then concentrated, purified through a series of steps, then converted to silver phosphate, which is pyrolyzed and analyzed by continuous-flow isotope ratio mass spectrometry (CF-IRMS). The isotopic signatures and/or fractionations associated with many of the potential reactions and transformations operating in the P cycle have been determined, and provide the basis for interpreting isotopic data that are obtained from the phosphate extracts.

  3. Calcium and phosphorus requirements of breeding bobwhite quail

    USGS Publications Warehouse

    DeWitt, J.B.; Nestler, R.B.; Derby, J.V., Jr.

    1949-01-01

    In the course of studies designed to determine the calcium and phosphorus requirements of breeding bobwhite quail, it was found that best results were obtained when the Ca/P ratio in the diet was approximately 2.3:1. Variations in the Ca/P ratio produced significant differences in results when the level of phosphorus in the diet was 0.75%, but the differences were less marked when the level of phosphorus was increased to 1.00%. Although diets containing 0.75% phosphorus and 1.8% calcium appeared adequate for reproduction, as judged by the criteria of the maintenance of satisfactory condition in the breeders, egg production, fertility, hatchability and survival of offspring during the first 5 days after hatching, it was found that the winter mortality of the offspring of birds fed such a diet was much greater than that occurring in the offspring of birds fed on diets containing 1.00 or 1.25% phosphorus. It is concluded that breeding bobwhite quail require diets furnishing approximately 1.00% phosphorus and 2.3% calcium.

  4. Phosphorus and Nitrogen Regulate Arbuscular Mycorrhizal Symbiosis in Petunia hybrida

    PubMed Central

    Nouri, Eva; Breuillin-Sessoms, Florence; Feller, Urs; Reinhardt, Didier

    2014-01-01

    Phosphorus and nitrogen are essential nutrient elements that are needed by plants in large amounts. The arbuscular mycorrhizal symbiosis between plants and soil fungi improves phosphorus and nitrogen acquisition under limiting conditions. On the other hand, these nutrients influence root colonization by mycorrhizal fungi and symbiotic functioning. This represents a feedback mechanism that allows plants to control the fungal symbiont depending on nutrient requirements and supply. Elevated phosphorus supply has previously been shown to exert strong inhibition of arbuscular mycorrhizal development. Here, we address to what extent inhibition by phosphorus is influenced by other nutritional pathways in the interaction between Petunia hybrida and R. irregularis. We show that phosphorus and nitrogen are the major nutritional determinants of the interaction. Interestingly, the symbiosis-promoting effect of nitrogen starvation dominantly overruled the suppressive effect of high phosphorus nutrition onto arbuscular mycorrhiza, suggesting that plants promote the symbiosis as long as they are limited by one of the two major nutrients. Our results also show that in a given pair of symbiotic partners (Petunia hybrida and R. irregularis), the entire range from mutually symbiotic to parasitic can be observed depending on the nutritional conditions. Taken together, these results reveal complex nutritional feedback mechanisms in the control of root colonization by arbuscular mycorrhizal fungi. PMID:24608923

  5. Phosphorus out-diffusion in laser molten silicon

    SciTech Connect

    Köhler, J. R.; Eisele, S. J.

    2015-04-14

    Laser doping via liquid phase diffusion enables the formation of defect free pn junctions and a tailoring of diffusion profiles by varying the laser pulse energy density and the overlap of laser pulses. We irradiate phosphorus diffused 100 oriented p-type float zone silicon wafers with a 5??m wide line focused 6.5?ns pulsed frequency doubled Nd:YVO{sub 4} laser beam, using a pulse to pulse overlap of 40%. By varying the number of laser scans N{sub s}?=?1, 2, 5, 10, 20, 40 at constant pulse energy density H?=?1.3?J/cm{sup 2} and H?=?0.79?J/cm{sup 2} we examine the out-diffusion of phosphorus atoms performing secondary ion mass spectroscopy concentration measurements. Phosphorus doping profiles are calculated by using a numerical simulation tool. The tool models laser induced melting and re-solidification of silicon as well as the out-diffusion of phosphorus atoms in liquid silicon during laser irradiation. We investigate the observed out-diffusion process by comparing simulations with experimental concentration measurements. The result is a pulse energy density independent phosphorus out-diffusion velocity v{sub out}?=?9?±?1?cm/s in liquid silicon, a partition coefficient of phosphorus 1?

  6. Determination of Total Particulate Phosphorus (TPP) and Particulate Inorganic Phosphorus (PIP) in Fresh/Estuarine/Coastal Waters

    E-print Network

    Boynton, Walter R.

    -colored complex by ascorbic acid. Color is proportional to phosphorus concentration. The method is used to analyze with a sulfuric acid-antimony-molybdate solution, and subsequently with an ascorbic acid solution, yielding

  7. Distribution Behavior of Phosphorus and Metallization of Iron Oxide in Carbothermic Reduction of High-Phosphorus Iron Ore

    NASA Astrophysics Data System (ADS)

    Cha, Ji-Whoe; Kim, Dong-Yuk; Jung, Sung-Mo

    2015-10-01

    Distribution behavior of phosphorus and metallization of iron ore in the carbothermic reduction of high-phosphorus iron ore were investigated. Reduction degree of the iron oxide was evaluated by quadruple mass spectrometry connected to thermogravimetric analysis. The distribution of some elements including phosphorus was examined by electron probe micro-analyzer mapping analyses. The reduction behavior of high-phosphorus iron ore was evaluated as a function of reduction temperature, C/O molar ratio, and CaO addition. High reduction temperature accelerated the reduction of both iron oxide and hydroxylapatite, and high C/O molar ratio also promotes both of them. Those were contradictory to the targets of higher reduction degree of iron oxide and of lower one of hydroxylapatite. It was confirmed that appropriate amount of CaO addition could enhance the reduction of iron oxide, and regulate the reduction of hydroxylapatite.

  8. Phosphorus dendrimers and photodynamic therapy. Spectroscopic studies on two dendrimer-photosensitizer complexes: Cationic phosphorus dendrimer with rose bengal and anionic phosphorus dendrimer with methylene blue.

    PubMed

    Dabrzalska, Monika; Zablocka, Maria; Mignani, Serge; Majoral, Jean Pierre; Klajnert-Maculewicz, Barbara

    2015-08-15

    Dendrimers due to their unique architecture may play an important role in drug delivery systems including chemotherapy, gene therapy and recently, photodynamic therapy as well. We investigated two dendrimer-photosensitizer systems in context of potential use of these systems in photodynamic therapy. The mixtures of an anionic phosphorus dendrimer of the second generation and methylene blue were studied by UV-vis spectroscopy while that of a cationic phosphorus dendrimer (third generation) and rose bengal were investigated by spectrofluorimetric methods. Spectroscopic analysis of these two systems revealed the formation of dendrimer-photosensitizer complexes via electrostatic interactions as well as ? stacking. The stoichiometry of the rose bengal-cationic dendrimer complex was estimated to be 7:1 and 9:1 for the methylene blue-anionic dendrimer complex. The results suggest that these polyanionic or polycationic phosphorus dendrimers can be promising candidates as carriers in photodynamic therapy. PMID:26117192

  9. First-principles study of the effect of phosphorus on nickel grain boundary

    SciTech Connect

    Liu, Wenguan; Ren, Cuilan; Han, Han E-mail: xuhongjie@sinap.ac.cn; Zou, Yang; Zhou, Xingtai; Huai, Ping; Xu, Hongjie E-mail: xuhongjie@sinap.ac.cn; Tan, Jie

    2014-01-28

    Based on first-principles quantum-mechanical calculations, the impurity-dopant effects of phosphorus on ?5(012) symmetrical tilt grain boundary in nickel have been studied. The calculated binding energy suggests that phosphorus has a strong tendency to segregate to the grain boundary. Phosphorus forms strong and covalent-like bonding with nickel, which is beneficial to the grain boundary cohesion. However, a too high phosphorus content can result in a thin and fragile zone in the grain boundary, due to the repulsion between phosphorus atoms. As the concentration of phosphorus increases, the strength of the grain boundary increases first and then decreases. Obviously, there exists an optimum concentration for phosphorus segregation, which is consistent with observed segregation behaviors of phosphorus in the grain boundary of nickel. This work is very helpful to understand the comprehensive effects of phosphorus.

  10. First-principles study of the effect of phosphorus on nickel grain boundary

    NASA Astrophysics Data System (ADS)

    Liu, Wenguan; Ren, Cuilan; Han, Han; Tan, Jie; Zou, Yang; Zhou, Xingtai; Huai, Ping; Xu, Hongjie

    2014-01-01

    Based on first-principles quantum-mechanical calculations, the impurity-dopant effects of phosphorus on ?5(012) symmetrical tilt grain boundary in nickel have been studied. The calculated binding energy suggests that phosphorus has a strong tendency to segregate to the grain boundary. Phosphorus forms strong and covalent-like bonding with nickel, which is beneficial to the grain boundary cohesion. However, a too high phosphorus content can result in a thin and fragile zone in the grain boundary, due to the repulsion between phosphorus atoms. As the concentration of phosphorus increases, the strength of the grain boundary increases first and then decreases. Obviously, there exists an optimum concentration for phosphorus segregation, which is consistent with observed segregation behaviors of phosphorus in the grain boundary of nickel. This work is very helpful to understand the comprehensive effects of phosphorus.

  11. Dynamics in phosphorus retention in wetlands upstream of Delavan Lake, Wisconsin

    USGS Publications Warehouse

    Robertson, Dale M.; Elder, John F.; Goddard, Gerald L.; James, William F.

    2009-01-01

    A phosphorus budget was constructed for Delavan Lake Inlet, a perennial riverine wetland with submersed and floating aquatic vegetation in southeastern Wisconsin, to better understand the phosphorus dynamics in natural wetlands and the role of wetlands in lake-rehabilitation efforts. During the growing season, the inlet served as a net source of phosphorus, primarily due to the release of phosphorus from the sediments. More phosphorus was released from the sediments of the inlet (600 kg) than was input from the upstream watershed (460 kg). This release was caused by high pH associated with high photosynthetic activity. During the remainder of the year, the inlet served as a net sink for phosphorus, retaining 6% of die phosphorus input from the watershed. Over the entire year, this wetland was a net source of over 500 kg of phosphorus to downstream Delavan Lake. A constructed riverine wetland upstream of Delavan Lake Inlet demonstrated a similar periodic release of phosphorus. However, in this case, the summer release of phosphorus was less than that trapped during the remainder of the year. The constructed wetland served as a net sink for approximately 20% of the input phosphorus on an annual time scale. The role of existing and constructed wetlands as phosphorus traps is complex. Wetlands can act as a source or a sink for phosphorus depending on the ambient conditions in die wetland. Howa wetland fits into a rehabilitation plan depends upon its net retention efficiency and the importance of the periodic releases of phosphorus to downstream waters.

  12. Uncertainty based analysis of the impact of watershed phosphorus load on reservoir phosphorus concentration

    NASA Astrophysics Data System (ADS)

    Karamouz, Mohammad; Taheriyoun, Masoud; Seyedabadi, Mohammadreza; Nazif, Sara

    2015-02-01

    In many regions of the world that depend on surface reservoirs as a source of water supply, eutrophication is a major water quality problem. Developing simulation models to evaluate the impact of watershed nutrient loads on the reservoir's water quality is an essential step in eutrophication management. In this regard, analysis of model uncertainty gives an opportunity to assess the reliability and the margin of safety of the model predictions for Total Maximum Daily Load (TMDL) from the watershed nutrient load. In this study, a computational procedure has been proposed for the analysis of the model uncertainties in simulation of watershed phosphorous load and reservoir phosphorous concentration. Data from the Aharchai watershed which is located upstream of the Satarkhan reservoir in the northwestern part of Iran, is used as the study area to test the effectiveness of the proposed methodology. The Soil and Water Assessment Tools (SWAT) is utilized for assessment of watershed phosphorus load as the main agent resulting in the reservoir eutrophication in the region. The most effective parameters in model performance are identified by a global sensitivity analysis technique named modified Fourier Amplitude Sensitivity Test (FAST) which can incorporate parameter interdependencies. The Generalized Likelihood Uncertainty Estimation (GLUE) technique is also applied to set up behavioral ranges of the parameters that are relevant to the actual observations. Finally, the cumulative weighted-likelihood distribution functions (CWLDF) are derived for outputs of the SWAT. They are used jointly for estimation of results uncertainty limits using the Copula method. To assess the effectiveness of applying Best Management Practices (BMPs) in the watershed, two scenarios of with and without BMPs application are tested. The results showed the effectiveness of the proposed model in uncertainty estimation of watershed phosphorus load and reservoir phosphorus concentration as well as the effectiveness of BMPs in reducing P loads from the watershed.

  13. Reactions of coordinated hydroxymethylphosphines with NH-functional amines: the phosphorus lone pair is crucial for the phosphorus Mannich reaction.

    PubMed

    Swor, Charles D; Hanson, Kyle R; Zakharov, Lev N; Tyler, David R

    2011-09-14

    Non-coordinated hydroxymethylphosphines react readily with primary and secondary amines by the phosphorus Mannich reaction. To determine if this reactivity can be used to synthesize phosphine macrocycles, trans-Fe(DHMPE)(2)Cl(2) (DHMPE = 1,2-bis(dihydroxymethylphosphino)ethane) was prepared and reacted with various amines. However, no phosphorus Mannich reactivity was observed. In order to understand why no reactions occurred, the Mannich reactivity of the borane-coordinated hydroxymethylphosphines DHMPE·2BH(3) and Ph(2)PCH(2)OH·BH(3) was investigated. These borane-coordinated phosphines also did not undergo the phosphorus Mannich reaction. These results suggest that the lone pair of electrons on the phosphorus atom is essential for the phosphorus Mannich reaction to occur, and therefore it is not possible to use this reaction in a templated synthesis of phosphine macrocycles. It is speculated that the mechanism of the phosphorus Mannich reaction may involve a methylenephosphonium intermediate, analogous to an iminium in the standard Mannich reaction. X-ray crystal structures of trans-Fe(DHMPE)(2)Cl(2) and DHMPE·2BH(3) are also presented. Both crystal structures display an extended hydrogen-bonding network in the solid state. PMID:21789320

  14. Distribution of phosphorus compounds in corn processing.

    PubMed

    Noureddini, H; Malik, M; Byun, J; Ankeny, A J

    2009-01-01

    Distillers dried grains with solubles (DDGS) and corn gluten feed (CGF) are major coproducts of ethanol production from corn dry grind and wet milling facilities, respectively. These coproducts contain important nutrients, nevertheless, high levels of phosphorus (P). About 50-80% of the P in these products is in an organically bound form known as phytate. The phytate P in these products cannot be digested by nonruminant animals. Consequently, large quantities of phytate are deposited into the soil with the animal wastes which potentially could cause P pollution in soil and underground water resources. As regulations on the concentration of P material in ethanol production coproducts become more restrictive, measures need to be taken for effective extraction of phytate P from the coproducts to make these processes more environmentally compatible. Proper marketing of coproducts is critical to the overall economy of ethanol production facilities. In this study, distribution of P compounds in different streams of dry grind and wet milling operations was determined. In the dry grind process, the highest P concentration was found to be in the condensed distillers solubles (CDS) at about 1.34 wt.% (db). About 59% of P in this stream was in phosphates form. The highest concentration of P in the wet milling process was found in the light steep water at about 3.4 wt.% (db). In this stream, about 22% of P was attributed to phosphates. PMID:18692392

  15. Metagenomic analysis of phosphorus removing sludgecommunities

    SciTech Connect

    Garcia Martin, Hector; Ivanova, Natalia; Kunin, Victor; Warnecke,Falk; Barry, Kerrie; McHardy, Alice C.; Yeates, Christine; He, Shaomei; Salamov, Asaf; Szeto, Ernest; Dalin, Eileen; Putnam, Nik; Shapiro, HarrisJ.; Pangilinan, Jasmyn L.; Rigoutsos, Isidore; Kyrpides, Nikos C.; Blackall, Linda Louise; McMahon, Katherine D.; Hugenholtz, Philip

    2006-02-01

    Enhanced Biological Phosphorus Removal (EBPR) is not wellunderstood at the metabolic level despite being one of the best-studiedmicrobially-mediated industrial processes due to its ecological andeconomic relevance. Here we present a metagenomic analysis of twolab-scale EBPR sludges dominated by the uncultured bacterium, "CandidatusAccumulibacter phosphatis." This analysis resolves several controversiesin EBPR metabolic models and provides hypotheses explaining the dominanceof A. phosphatis in this habitat, its lifestyle outside EBPR and probablecultivation requirements. Comparison of the same species from differentEBPR sludges highlights recent evolutionary dynamics in the A. phosphatisgenome that could be linked to mechanisms for environmental adaptation.In spite of an apparent lack of phylogenetic overlap in the flankingcommunities of the two sludges studied, common functional themes werefound, at least one of them complementary to the inferred metabolism ofthe dominant organism. The present study provides a much-needed blueprintfor a systems-level understanding of EBPR and illustrates thatmetagenomics enables detailed, often novel, insights into evenwell-studied biological systems.

  16. Photogalvanic effect in monolayer black phosphorus

    NASA Astrophysics Data System (ADS)

    Xie, Yiqun; Zhang, Lei; Zhu, Yu; Liu, Lei; Guo, Hong

    2015-11-01

    We report a first-principles theoretical approach for analyzing linear and circular photogalvanic effects (PGEs) based on density functional theory within the nonequilibrium Green’s function formalism. Using this approach we investigate the PGE phenomena in monolayer black phosphorus (MBP) doped with sulfur atoms. The impurity doping breaks the space inversion symmetry of pristine MBP, leading to a C s symmetry with a mirror reflection plane normal to the zigzag direction of the MBP lattice. Governed by this symmetry, a linear PGE is induced in both zigzag and armchair directions, and a circular PGE is induced along the zigzag direction. A robust broadband photoresponse is found from the near-infrared to the visible range for the MBP device. There is a strong anisotropy in PGE: photoresponse in the zigzag direction can be larger by an order of magnitude than that in the armchair direction. We identify the origin of the observed PGE as the inter-band transitions from the impurity and valence bands to the conduction bands, which involves a transfer of angular momentum from photons to electrons.

  17. The role of diet in phosphorus demand

    NASA Astrophysics Data System (ADS)

    Metson, Geneviève S.; Bennett, Elena M.; Elser, James J.

    2012-12-01

    Over the past 50 years, there have been major changes in human diets, including a global average increase in meat consumption and total calorie intake. We quantified how changes in annual per capita national average diets affected requirements for mined P between 1961 and 2007, starting with the per capita availability of a food crop or animal product and then determining the P needed to grow the product. The global per capita P footprint increased 38% over the 46 yr time period, but there was considerable variability among countries. Phosphorus footprints varied between 0.35 kg P capita-1 yr-1 (DPR Congo, 2007) and 7.64 kg P capita-1 yr-1 (Luxembourg, 2007). Temporal trends also differed among countries; for example, while China’s P footprint increased almost 400% between 1961 and 2007, the footprints of other countries, such as Canada, decreased. Meat consumption was the most important factor affecting P footprints; it accounted for 72% of the global average P footprint. Our results show that dietary shifts are an important component of the human amplification of the global P cycle. These dietary trends present an important challenge for sustainable P management.

  18. Determination of Phosphorus in Cola Drinks

    NASA Astrophysics Data System (ADS)

    Lozano-Calero, Diego; Martìn-Palomeque, Pilar; Madueño-Lorguillo, Silvia

    1996-12-01

    Laboratory experiments can improve student interest in science. However, the contrary effect could occur if they are not well designed and seem tedious, too laborious, and disconnected from daily life. Cola beverages are one of the most widely consumed drinks and are most popular among students. Much attention is being paid to possible consequences of excessive consumption for human health. Intensive efforts are being made to assess the erosive potential for teeth because of the beverages' acidity (1, 2); adverse effects secondary to high caffeine intake (e.g., hypertension, allergic reactions, gastrointestinal disturbances) (3 - 5); and adverse effects on calcium metabolism due to their high phosphoric acid content, which combined with low dietary calcium intake could increase the risk of suffering from bone diseases (6 - 9). We propose here the quantification of the phosphorus content in this kind of drinks by a different procedure from that previously described by Murphy in this Journal (10). We think this laboratory experiment will seem very interesting to students.

  19. Phosphorus: a limiting nutrient for humanity?

    PubMed

    Elser, James J

    2012-12-01

    Phosphorus is a chemical element that is essential to life because of its role in numerous key molecules, including DNA and RNA; indeed, organisms require large amounts of P to grow rapidly. However, the supply of P from the environment is often limiting to production, including to crops. Thus, large amounts of P are mined annually to produce fertilizer that is applied in support of the 'Green Revolution.' However, much of this fertilizer eventually ends up in rivers, lakes and oceans where it causes costly eutrophication. Furthermore, given increasing human population, expanding meat consumption, and proliferating bioenergy pressures, concerns have recently been raised about the long-term geological, economic, and geopolitical viability of mined P for fertilizer production. Together, these issues highlight the non-sustainable nature of current human P use. To achieve P sustainability, farms need to become more efficient in how they use P while society as a whole must develop technologies and practices to recycle P from the food chain. Such large-scale changes will probably require a radical restructuring of the entire food system, highlighting the need for prompt but sustained action. PMID:22465489

  20. Lowland fluvial phosphorus altered by dams

    NASA Astrophysics Data System (ADS)

    Zhou, Jianjun; Zhang, Man; Lin, Binliang; Lu, Pingyu

    2015-04-01

    Dams affect ecosystems, but their physical link to the variations in fluvial fluxes and downstream ecological consequences are inadequately understood. After estimating the current effects of the Three Gorges project and other reservoirs upstream on the Yangtze River on the fluvial phosphorus (P) in the middle and lower Yangtze River, we further investigated the long-term effects of dams on the fluvial regimes of P and P-enriched sediment (PES). Simultaneously measured P distributions with sediment size (PDSS) from the Three Gorges Reservoir (TGR) proved that the areal density of particulate P (PP) bound on graded sediment can be measured using the surface area concentration of the total sediment. A PDSS relationship is obtained and the selective transport and long-term sedimentation of P are simulated using a nonuniform suspended sediment model, which incorporates the PDSS formula. The computations revealed that a reservoir would significantly lower the downstream availability of P in the dry season and promote high pulses of P in summer when the reservoir is flushed as sedimentation accumulates. As a result, the P buffering and replenishing mechanism in the pristine ecosystem from upstream supplies and local re-suspension are permanently eliminated when a regulating reservoir is built upstream. This change is irreversible if reservoir regulation continues. Changes could potentially aggravate the existing P-limitation, decrease the water's ability to adjust nutrient/pollutant fluctuations, accumulate a greater surplus of carbon and nitrogen, and even exacerbate blooms in favorable conditions.

  1. Global phosphorus retention by river damming

    PubMed Central

    Maavara, Taylor; Parsons, Christopher T.; Ridenour, Christine; Stojanovic, Severin; Dürr, Hans H.; Powley, Helen R.; Van Cappellen, Philippe

    2015-01-01

    More than 70,000 large dams have been built worldwide. With growing water stress and demand for energy, this number will continue to increase in the foreseeable future. Damming greatly modifies the ecological functioning of river systems. In particular, dam reservoirs sequester nutrient elements and, hence, reduce downstream transfer of nutrients to floodplains, lakes, wetlands, and coastal marine environments. Here, we quantify the global impact of dams on the riverine fluxes and speciation of the limiting nutrient phosphorus (P), using a mechanistic modeling approach that accounts for the in-reservoir biogeochemical transformations of P. According to the model calculations, the mass of total P (TP) trapped in reservoirs nearly doubled between 1970 and 2000, reaching 42 Gmol y?1, or 12% of the global river TP load in 2000. Because of the current surge in dam building, we project that by 2030, about 17% of the global river TP load will be sequestered in reservoir sediments. The largest projected increases in TP and reactive P (RP) retention by damming will take place in Asia and South America, especially in the Yangtze, Mekong, and Amazon drainage basins. Despite the large P retention capacity of reservoirs, the export of RP from watersheds will continue to grow unless additional measures are taken to curb anthropogenic P emissions. PMID:26644553

  2. Photogalvanic effect in monolayer black phosphorus.

    PubMed

    Xie, Yiqun; Zhang, Lei; Zhu, Yu; Liu, Lei; Guo, Hong

    2015-11-13

    We report a first-principles theoretical approach for analyzing linear and circular photogalvanic effects (PGEs) based on density functional theory within the nonequilibrium Green's function formalism. Using this approach we investigate the PGE phenomena in monolayer black phosphorus (MBP) doped with sulfur atoms. The impurity doping breaks the space inversion symmetry of pristine MBP, leading to a C s symmetry with a mirror reflection plane normal to the zigzag direction of the MBP lattice. Governed by this symmetry, a linear PGE is induced in both zigzag and armchair directions, and a circular PGE is induced along the zigzag direction. A robust broadband photoresponse is found from the near-infrared to the visible range for the MBP device. There is a strong anisotropy in PGE: photoresponse in the zigzag direction can be larger by an order of magnitude than that in the armchair direction. We identify the origin of the observed PGE as the inter-band transitions from the impurity and valence bands to the conduction bands, which involves a transfer of angular momentum from photons to electrons. PMID:26486805

  3. Black phosphorus radio-frequency transistors.

    PubMed

    Wang, Han; Wang, Xiaomu; Xia, Fengnian; Wang, Luhao; Jiang, Hao; Xia, Qiangfei; Chin, Matthew L; Dubey, Madan; Han, Shu-jen

    2014-11-12

    Few-layer and thin film forms of layered black phosphorus (BP) have recently emerged as a promising material for applications in high performance nanoelectronics and infrared optoelectronics. Layered BP thin films offer a moderate bandgap of around 0.3 eV and high carrier mobility, which lead to transistors with decent on-off ratios and high on-state current densities. Here, we demonstrate the gigahertz frequency operation of BP field-effect transistors for the first time. The BP transistors demonstrated here show respectable current saturation with an on-off ratio that exceeds 2 × 10(3). We achieved a current density in excess of 270 mA/mm and DC transconductance above 180 mS/mm for hole conduction. Using standard high frequency characterization techniques, we measured a short-circuit current-gain cutoff frequency fT of 12 GHz and a maximum oscillation frequency fmax of 20 GHz in 300 nm channel length devices. BP devices may offer advantages over graphene transistors for high frequency electronics in terms of voltage and power gain due to the good current saturation properties arising from their finite bandgap, thus can be considered as a promising candidate for the future high performance thin film electronics technology for operation in the multi-GHz frequency range and beyond. PMID:25347787

  4. Hydrologic transport and partitioning of phosphorus fractions

    NASA Astrophysics Data System (ADS)

    Berretta, C.; Sansalone, J.

    2011-06-01

    SummaryPhosphorus (P) in rainfall-runoff partitions between dissolved and particulate matter (PM) bound phases. This study investigates the transport and partitioning of P to PM fractions in runoff from a landscaped and biogenically-loaded carpark in Gainesville, FL (GNV). Additionally, partitioning and concentration results are compared to a similarly-sized concrete-paved source area of a similar rainfall depth frequency distribution in Baton Rouge, LA (BTR), where in contrast vehicular traffic represents the main source of pollutants. Results illustrate that concentrations of P fractions (dissolved, suspended, settleable and sediment) for GNV are one to two orders of magnitude higher than BTR. Despite these differences the dissolved fraction ( f d) and partitioning coefficient ( K d) distributions are similar, illustrating that P is predominantly bound to PM fractions. Examining PM size fractions, specific capacity for P (PSC) indicates that the P concentration order is suspended > settleable > sediment for GNV, similarly to BTR. For GNV the dominant PM mass fraction is sediment (>75 ?m), while the mass of P is distributed predominantly between sediment and suspended (<25 ?m) fractions since these PM mass fractions dominated the settleable one. With respect to transport of PM and P fractions the predominance of events for both areas is mass-limited first-flush, although each fraction illustrated unique washoff parameters. However, while transport is predominantly mass-limited, the transport of each PM and P fraction is influenced by separate hydrologic parameters.

  5. Phosphorus and nitrogen in coral reef sediments

    SciTech Connect

    Entsch, B.; Boto, K.G.; Sim, R.G.; Wellington, J.T.

    1983-05-01

    The occurrence of P and N in the sediments has been investigated on Davies Reef in the central region of the Great Barrier Reef Complex. Concentrations of inorganic P and N in the water were typical of nutrient-depleted tropical surface water. Carbonate sediments were found to contain a uniform pool of P (300 ppm by wt), principally in the form of inorganic phosphate. The interstitial water of the surface layer of sediment contained micromolar concentrations of inorganic P and even higher concentrations of inorganic N, principally as ammonium. These nutrient concentrations were considered too low to compete significantly with the uptake of available phasphate into algae. The presence of ammonium and soluble P was associated with anaerobic redox potentials in the sediments just below the surface. Soluble phosphorus was in equilibrium with a small, rapidly exchangeable fraction of the sedimentary pool of inorganic phosphate. Analyses of P in growing tips of Halimeda and corals (which supply more than half of reef sediments) suggested that the skeletons provide a biological mechanism for the replenishment of at least some of the sedimentary pool. Ratios of C:N:P for a selection of benthic algae were used as a preliminary indicator of thier N and P status.

  6. Structural stability of phases of black phosphorus

    SciTech Connect

    Chang, K.J.; Cohen, M.L.

    1986-05-01

    The pseudopotential method is used to examine the structural stability of high-pressure orthorhombic, rhombohedral (A-7), and simple cubic (sc) phases of black phosphorus. The calculated ground-state properties are in good agreement with the measured values for each phase. A total-energy study gives the orthorhombic phase as the most stable structure at low pressures. At higher pressures it transforms into the A-7 structure in agreement with experiment. At even higher pressure, the calculations indicate that the A-7 phase is stable with respect to the sc structure as is the case for other group-V elements. Measurements show that the sc phase is stable at 110 kbar at room temperature. This suggests that the calculated crystal energy for the A-7 phase is too low and it requires a finite energy shift. With an a priori energy shift, the transition pressure and volume are in good agreement with experiment. A possible source of this correction is the zero-point energy or temperature renormalization of the phonon frequencies caused by anharmonicity. The changes of the energy band structures and charge densities for the A-7 displacement and selected phonon frequencies are calculated.

  7. Forms of organic phosphorus in wetland soils

    NASA Astrophysics Data System (ADS)

    Cheesman, A. W.; Turner, B. L.; Reddy, K. R.

    2014-06-01

    Phosphorus (P) cycling in freshwater wetlands is dominated by biological mechanisms, yet there has been no comprehensive examination of the forms of biogenic P (i.e. forms derived from biological activity) in wetland soils. We used solution 31P NMR spectroscopy to identify and quantify P forms in surface soils of 28 palustrine wetlands spanning a range of climatic, hydro-geomorphic and vegetation types. Total P concentrations ranged between 51 and 3516 ?g P g

  8. Forms of organic phosphorus in wetland soils

    NASA Astrophysics Data System (ADS)

    Cheesman, A. W.; Turner, B. L.; Reddy, K. R.

    2014-12-01

    Phosphorus (P) cycling in freshwater wetlands is dominated by biological mechanisms, yet there has been no comprehensive examination of the forms of biogenic P (i.e., forms derived from biological activity) in wetland soils. We used solution 31P NMR spectroscopy to identify and quantify P forms in surface soils of 28 palustrine wetlands spanning a range of climatic, hydrogeomorphic, and vegetation types. Total P concentrations ranged between 51 and 3516 ?g P g-1, of which an average of 58% was extracted in a single-step NaOH-EDTA procedure. The extracts contained a broad range of P forms, including phosphomonoesters (averaging 24% of the total soil P), phosphodiesters (averaging 10% of total P), phosphonates (up to 4% of total P), and both pyrophosphate and long-chain polyphosphates (together averaging 6% of total P). Soil P composition was found to be dependant upon two key biogeochemical properties: organic matter content and pH. For example, stereoisomers of inositol hexakisphosphate were detected exclusively in acidic soils with high mineral content, while phosphonates were detected in soils from a broad range of vegetation and hydrogeomorphic types but only under acidic conditions. Conversely inorganic polyphosphates occurred in a broad range of wetland soils, and their abundance appears to reflect more broadly that of a "substantial" and presumably active microbial community with a significant relationship between total inorganic polyphosphates and microbial biomass P. We conclude that soil P composition varies markedly among freshwater wetlands but can be predicted by fundamental soil properties.

  9. Global phosphorus retention by river damming.

    PubMed

    Maavara, Taylor; Parsons, Christopher T; Ridenour, Christine; Stojanovic, Severin; Dürr, Hans H; Powley, Helen R; Van Cappellen, Philippe

    2015-12-22

    More than 70,000 large dams have been built worldwide. With growing water stress and demand for energy, this number will continue to increase in the foreseeable future. Damming greatly modifies the ecological functioning of river systems. In particular, dam reservoirs sequester nutrient elements and, hence, reduce downstream transfer of nutrients to floodplains, lakes, wetlands, and coastal marine environments. Here, we quantify the global impact of dams on the riverine fluxes and speciation of the limiting nutrient phosphorus (P), using a mechanistic modeling approach that accounts for the in-reservoir biogeochemical transformations of P. According to the model calculations, the mass of total P (TP) trapped in reservoirs nearly doubled between 1970 and 2000, reaching 42 Gmol y(-1), or 12% of the global river TP load in 2000. Because of the current surge in dam building, we project that by 2030, about 17% of the global river TP load will be sequestered in reservoir sediments. The largest projected increases in TP and reactive P (RP) retention by damming will take place in Asia and South America, especially in the Yangtze, Mekong, and Amazon drainage basins. Despite the large P retention capacity of reservoirs, the export of RP from watersheds will continue to grow unless additional measures are taken to curb anthropogenic P emissions. PMID:26644553

  10. Phosphorus and phosphorus nitrogen doped carbon nanotubes for ultrasensitive and selective molecular detection

    SciTech Connect

    Cruz Silva, Eduardo; Lopez, Florentino; Munoz-Sandoval, Emilio; Sumpter, Bobby G; Terrones Maldonado, Humberto; Charlier, Jean Christophe; Meunier, Vincent; Terrones Maldonado, Mauricio

    2011-01-01

    A first-principles approach is used to establish that substitutional phosphorus atoms within carbon nanotubes strongly modify the chemical properties of the surface, thus creating highly localized sites with specific affinity towards acceptor molecules. Phosphorus nitrogen co-dopants within the tubes have a similar effect for acceptor molecules, but the P N bond can also accept charge, resulting in affinity towards donor molecules. This molecular selectivity is illustrated in CO and NH3 adsorbed on PN-doped nanotubes, O2 on P-doped nanotubes, and NO2 and SO2 on both P- and PN-doped nanotubes. The adsorption of different chemical species onto the doped nanotubes modifies the dopant-induced localized states, which subsequently alter the electronic conductance. Although SO2 and CO adsorptions cause minor shifts in electronic conductance, NH3, NO2, and O2 adsorptions induce the suppression of a conductance dip. Conversely, the adsorption of NO2 on PN-doped nanotubes is accompanied with the appearance of an additional dip in conductance, correlated with a shift of the existing ones. Overall these changes in electric conductance provide an efficient way to detect selectively the presence of specific molecules. Additionally, the high oxidation potential of the P-doped nanotubes makes them good candidates for electrode materials in hydrogen fuel cells.

  11. Species and distribution of inorganic and organic phosphorus in enhanced phosphorus removal aerobic granular sludge.

    PubMed

    Huang, Wenli; Huang, Weiwei; Li, Huifang; Lei, Zhongfang; Zhang, Zhenya; Tay, Joo Hwa; Lee, Duu-Jong

    2015-10-01

    The species and distribution of phosphorus (P) in an enhanced biological phosphorus removal (EBPR)-aerobic granular sludge (AGS) were fractionated and further analyzed. Results showed that microbial cells, extracellular polymeric substances (EPS) and mineral precipitates contributed about 73.7%, 17.6% and 5.3-6.4% to the total P (TP) of EBPR-AGS, respectively. Inorganic P (IP) species were orthophosphate, pyrophosphate and polyphosphate among which polyphosphate was the major P species in the AGS, cells and EPS. Monoester and diester phosphates were identified as the organic P (OP) species in the AGS and cells. Hydroxyapatite (Ca5(PO4)3OH) and calcium phosphate (Ca2(PO4)3) were the dominant P minerals accumulated in the core of the granules. Cells along with polyphosphate were mainly in the outer layer of AGS while EPS were distributed in the whole granules. Based on the above results, the distribution of IP and OP species in AGS has been conceived. PMID:26144019

  12. Removing Phosphorus from Aqueous Solutions Using Lanthanum Modified Pine Needles

    PubMed Central

    Wang, Xianze; Liu, Zhongmou; Liu, Jiancong; Huo, Mingxin; Huo, Hongliang; Yang, Wu

    2015-01-01

    The renewable pine needles was used as an adsorbent to remove phosphorus from aqueous solutions. Using batch experiments, pine needles pretreated with alkali-isopropanol (AI) failed to effectively remove phosphorus, while pine needles modified with lanthanum hydroxide (LH) showed relatively high removal efficiency. LH pine needles were effective at a wide pH ranges, with the highest removal efficiency reaching approximately 85% at a pH of 3. The removal efficiency was kept above 65% using 10 mg/L phosphorus solutions at desired pH values. There was no apparent significant competitive behavior between co-existing anions of sulfate, nitrate, and chloride (SO42-, NO3- and Cl-); however, CO32- exhibited increased interfering behavior as concentrations increased. An intraparticle diffusion model showed that the adsorption process occurred in three phases, suggesting that a boundary layer adsorption phenomena slightly affected the adsorption process, and that intraparticle diffusion was dominant. The adsorption process was thermodynamically unfavorable and non-spontaneous; temperature increases improved phosphorus removal. Total organic carbon (TOC) assays indicated that chemical modification reduced the release of soluble organic compounds from 135.6 mg/L to 7.76 mg/L. This new information about adsorption performances provides valuable information, and can inform future technological applications designed to remove phosphorus from aqueous solutions. PMID:26630014

  13. Transport properties of ultrathin black phosphorus on hexagonal boron nitride

    SciTech Connect

    Doganov, Rostislav A.; Özyilmaz, Barbaros; Koenig, Steven P.; Yeo, Yuting; Watanabe, Kenji; Taniguchi, Takashi

    2015-02-23

    Ultrathin black phosphorus, or phosphorene, is a two-dimensional material that allows both high carrier mobility and large on/off ratios. Similar to other atomic crystals, like graphene or layered transition metal dichalcogenides, the transport behavior of few-layer black phosphorus is expected to be affected by the underlying substrate. The properties of black phosphorus have so far been studied on the widely utilized SiO{sub 2} substrate. Here, we characterize few-layer black phosphorus field effect transistors on hexagonal boron nitride—an atomically smooth and charge trap-free substrate. We measure the temperature dependence of the field effect mobility for both holes and electrons and explain the observed behavior in terms of charged impurity limited transport. We find that in-situ vacuum annealing at 400?K removes the p-doping of few-layer black phosphorus on both boron nitride and SiO{sub 2} substrates and reduces the hysteresis at room temperature.

  14. Temperature dependent phonon shifts in few-layer black phosphorus.

    PubMed

    Late, Dattatray J

    2015-03-18

    Atomically thin two-dimensional (2D) sheets of black phosphorus have attracted much attention due to their potential for future nanoelectronic and photonics device applications. Present investigations deal with the temperature dependent phonon shifts in a few-layer black phosphorus nanosheet sample prepared using micromechanical exfoliation on a 300 nm SiO2/Si substrate. The temperature dependent Raman spectroscopy experiments were carried out on a few-layer black phosphorus sample, which depicts softening of Ag(1), B2g, and Ag(2) modes as temperature increases from 77 to 673 K. The calculated temperature coefficients for Ag(1), B2g, and Ag(2) modes of the few-layer black phosphorus nanosheet sample were observed to be -0.01, -0.013, and -0.014 cm(-1) K(-1), respectively. The temperature dependent softening modes of black phosphorus results were explained on the basis of a double resonance process which is more active in an atomically thin sample. This process can also be fundamentally pertinent in other promising and emerging 2D ultrathin layer and heterostructured materials. PMID:25730146

  15. Phosphorus dynamics within agricultural drainage ditches in the lower Mississippi Alluvial Valley

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Excessive phosphorus loading from fertilizers in agriculture results in enriched runoff and downstream freshwater and saltwater aquatic system eutrophication. This study evaluated phosphorus dynamics in agricultural drainage ditches across eight sites within the Lower Mississippi Alluvial Valley (LM...

  16. 75 FR 36306 - Chemical Mixtures Containing Listed Forms of Phosphorus and Change in Application Process

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-06-25

    ...phosphorus is stabilized against chemical reactions prior to its use by industry...matrix that protects it from chemical reactions. The amount of red phosphorus...plays an important role in the chemical reaction to produce...

  17. PHOSPHORUS-DEFECT INTERACTIONS DURING THERMAL ANNEALING OF ION IMPLANTED SILICON

    E-print Network

    Florida, University of

    PHOSPHORUS-DEFECT INTERACTIONS DURING THERMAL ANNEALING OF ION IMPLANTED SILICON By PATRICK HENRY for providing the CVD grown boron spike material and performing several of the phosphorus implants. I would also

  18. Response of nitrogen and phosphorus leaching and soil properties to applications of biosolids during turfgrass establishment 

    E-print Network

    Kerns, James Patrick

    2005-02-17

    Regulations for total maximum daily loads require management of phosphorus loading from farms and municipalities. This study evaluated environmental impacts of a system for using and exporting the phosphorus in composted ...

  19. Use of reactive materials to bind phosphorus.

    PubMed

    Chardon, Wim J; Groenenberg, Jan E; Temminghoff, Erwin J M; Koopmans, Gerwin F

    2012-01-01

    Phosphorus (P) losses from agricultural soils have caused surface water quality impairment in many regions of the world, including The Netherlands. Due to the large amounts of P accumulated in Dutch soils, the generic fertilizer and manure policy will not be sufficient to reach in time the surface water quality standards of the European Water Framework Directive. Additional measures must be considered to further reduce P enrichment of surface waters. One option is to immobilize P in soils or manure or to trap P when it moves through the landscape by using reactive materials with a large capacity to retain P. We characterized and tested two byproducts of the process of purification of deep groundwater for drinking water that could be used as reactive materials: iron sludge and iron-coated sand. Both materials contain low amounts of inorganic contaminants, which also have a low (bio)availability, and bound a large amount of P. We could describe sorption of P to the iron sludge in batch experiments well with the kinetic Freundlich equation (Q = × t (m) × C(n)). Kinetics had a large influence on P sorption in batch and column experiments and should be taken into account when iron-containing materials are tested for their capability to immobilize or trap P. A negative aspect of the iron sludge is its low hydraulic conductivity; even when mixed with pure sand to a mixture containing 20% sludge, the conductivity was very low, and only 10% sludge may be needed before application is possible in filters or barriers for removing P from groundwater. Due to its much higher hydraulic conductivity, iron-coated sand has greater potential for use under field conditions. Immobilizing P could be an option for using iron sludge as a reactive material. PMID:22565245

  20. Reducing phosphorus runoff from dairy farms.

    PubMed

    Bosch, Darrell J; Wolfe, Mary Leigh; Knowlton, Katharine F

    2006-01-01

    Phosphorus (P) runoff from manure can lead to eutrophication of surface water and algae growth. This study evaluates the impacts of alternative P reduction practices on dairy farm net returns and on potential P runoff. The P control practices include dairy herd nutrient management, crop nutrient management, and runoff and erosion control. Four farms representative of dairies in the Virginia Shenandoah Valley are simulated including dairies with and without supplementary broiler enterprises and with average and below average land area. A mathematical programming model was developed to predict farm production and net returns and the GLEAMS model was used to predict potential P runoff. The farms are evaluated under four scenarios: Scenario 1, no constraint on P runoff with access to crop nutrient, runoff and erosion control strategies but no access to dairy herd nutrient control strategies; Scenario 2, no constraint on P runoff with access to all crop and dairy herd nutrient control strategies; Scenario 3, constraint on P runoff with access to crop nutrient, runoff and erosion control strategies but no access to dairy herd nutrient control strategies; and Scenario 4, constraint on P runoff with access to all crop and dairy herd nutrient control strategies. Under Scenario 2, the herd nutrient control strategies increase milk output per cow and net returns on both farms and reduce P content of manure and P runoff. Under Scenario 3, limiting P runoff reduces farm returns by 1 and 3% on the average and small farms, respectively. Under Scenario 4, the P runoff constraint is less costly, reducing returns by less than 1% on both farms. Animal nutrient control strategies should be an important part of pollution control policies and programs for livestock intensive watersheds. PMID:16641330

  1. Scaling the respiratory metabolism to phosphorus relationship in plant seedlings.

    PubMed

    Wang, Zhi-Qiang; Huang, Heng; Deng, Jian-Ming; Liu, Jian-Quan

    2015-01-01

    There are empirical indications of an isometric scaling relationship between plants' respiratory metabolism rates and nitrogen contents. To test the hypothesis that there may be a similar relationship between plants' respiratory metabolism and phosphorus contents we used data obtained from 150 laboratory and field-grown seedlings representing 30 herbaceous species and 20 woody deciduous species. Our results show that whole-plant respiration rates strongly scaled to the 0.81-power of the whole-plant phosphorus content, across wide ranges of growth conditions and functional classifications. Moreover, we also found a similar scaling exponent between whole-plant respiration rates and total nitrogen contents for the same set of samples. The similarities of the metabolic scaling relationships suggest that similar mechanisms may be involved in the transport and storage of phosphorus and nitrogen in plants. PMID:26560344

  2. Integrated nutrient removal design for very low phosphorus levels.

    PubMed

    Johnson, Bruce R; Daigger, Glen T

    2009-01-01

    The State of Washington has found that the Spokane River is DO impaired, and is requiring dischargers to reduce phosphorus inputs to the river. Spokane County elected to build a new water recovery facility with a target effluent total phosphorus level of 50 microg/L on a seasonal average basis. Spokane County elected to use a private company to design/build and operate their facility. The very low nutrient requirements, and lack of historical operating information, necessitated an integrated approach to the nutrient removal design while considering the risks and benefits of the various treatment options. The process selection evaluated membrane bioreactors and tertiary membranes for the primary liquids process in combination with chemical and/or biological phosphorus removal. The final process selection included chemically enhanced primary treatment, membrane bioreactor with metal salts, and dewatering liquor treatment with an innovative post aerobic digestion step. PMID:19901479

  3. Pressure-Induced Electronic Transition in Black Phosphorus.

    PubMed

    Xiang, Z J; Ye, G J; Shang, C; Lei, B; Wang, N Z; Yang, K S; Liu, D Y; Meng, F B; Luo, X G; Zou, L J; Sun, Z; Zhang, Y; Chen, X H

    2015-10-30

    In a semimetal, both electrons and holes contribute to the density of states at the Fermi level. The small band overlaps and multiband effects engender novel electronic properties. We show that a moderate hydrostatic pressure effectively suppresses the band gap in the elemental semiconductor black phosphorus. An electronic topological transition takes place at approximately 1.2 GPa, above which black phosphorus evolves into a semimetal state that is characterized by a colossal positive magnetoresistance and a nonlinear field dependence of Hall resistivity. The Shubnikov-de Haas oscillations detected in magnetic field reveal the complex Fermi surface topology of the semimetallic phase. In particular, we find a nontrivial Berry phase in one Fermi surface that emerges in the semimetal state, as evidence of a Dirac-like dispersion. The observed semimetallic behavior greatly enriches the material property of black phosphorus and sets the stage for the exploration of novel electronic states in this material. PMID:26565480

  4. Creating a Stable Oxide at the Surface of Black Phosphorus.

    PubMed

    Edmonds, M T; Tadich, A; Carvalho, A; Ziletti, A; O'Donnell, K M; Koenig, S P; Coker, D F; Özyilmaz, B; Neto, A H Castro; Fuhrer, M S

    2015-07-15

    The stability of the surface of in situ cleaved black phosphorus crystals upon exposure to atmosphere is investigated with synchrotron-based photoelectron spectroscopy. After 2 days atmosphere exposure a stable subnanometer layer of primarily P2O5 forms at the surface. The work function increases by 0.1 eV from 3.9 eV for as-cleaved black phosphorus to 4.0 eV after formation of the 0.4 nm thick oxide, with phosphorus core levels shifting by <0.1 eV. The results indicate minimal charge transfer, suggesting that the oxide layer is suitable for passivation or as an interface layer for further dielectric deposition. PMID:26126232

  5. Pressure-Induced Electronic Transition in Black Phosphorus

    NASA Astrophysics Data System (ADS)

    Xiang, Z. J.; Ye, G. J.; Shang, C.; Lei, B.; Wang, N. Z.; Yang, K. S.; Liu, D. Y.; Meng, F. B.; Luo, X. G.; Zou, L. J.; Sun, Z.; Zhang, Y.; Chen, X. H.

    2015-10-01

    In a semimetal, both electrons and holes contribute to the density of states at the Fermi level. The small band overlaps and multiband effects engender novel electronic properties. We show that a moderate hydrostatic pressure effectively suppresses the band gap in the elemental semiconductor black phosphorus. An electronic topological transition takes place at approximately 1.2 GPa, above which black phosphorus evolves into a semimetal state that is characterized by a colossal positive magnetoresistance and a nonlinear field dependence of Hall resistivity. The Shubnikov-de Haas oscillations detected in magnetic field reveal the complex Fermi surface topology of the semimetallic phase. In particular, we find a nontrivial Berry phase in one Fermi surface that emerges in the semimetal state, as evidence of a Dirac-like dispersion. The observed semimetallic behavior greatly enriches the material property of black phosphorus and sets the stage for the exploration of novel electronic states in this material.

  6. Exceptional and Anisotropic Transport Properties of Photocarriers in Black Phosphorus.

    PubMed

    He, Jiaqi; He, Dawei; Wang, Yongsheng; Cui, Qiannan; Bellus, Matthew Z; Chiu, Hsin-Ying; Zhao, Hui

    2015-06-23

    One key challenge in developing postsilicon electronic technology is to find ultrathin channel materials with high charge mobilities and sizable energy band gaps. Graphene can offer extremely high charge mobilities; however, the lack of a band gap presents a significant barrier. Transition metal dichalcogenides possess sizable and thickness-tunable band gaps; however, their charge mobilities are relatively low. Here we show that black phosphorus has room-temperature charge mobilities on the order of 10(4) cm(2) V(-1) s(-1), which are about 1 order of magnitude larger than silicon. We also demonstrate strong anisotropic transport in black phosphorus, where the mobilities along the armchair direction are about 1 order of magnitude larger than in the zigzag direction. A photocarrier lifetime as long as 100 ps is also determined. These results illustrate that black phosphorus is a promising candidate for future electronic and optoelectronic applications. PMID:25961945

  7. Scaling the respiratory metabolism to phosphorus relationship in plant seedlings

    PubMed Central

    Wang, Zhi-Qiang; Huang, Heng; Deng, Jian-Ming; Liu, Jian-Quan

    2015-01-01

    There are empirical indications of an isometric scaling relationship between plants’ respiratory metabolism rates and nitrogen contents. To test the hypothesis that there may be a similar relationship between plants’ respiratory metabolism and phosphorus contents we used data obtained from 150 laboratory and field-grown seedlings representing 30 herbaceous species and 20 woody deciduous species. Our results show that whole-plant respiration rates strongly scaled to the 0.81-power of the whole-plant phosphorus content, across wide ranges of growth conditions and functional classifications. Moreover, we also found a similar scaling exponent between whole-plant respiration rates and total nitrogen contents for the same set of samples. The similarities of the metabolic scaling relationships suggest that similar mechanisms may be involved in the transport and storage of phosphorus and nitrogen in plants. PMID:26560344

  8. Phosphorus in the Young Supernova Remnant Cassiopeia A

    E-print Network

    Koo, Bon-Chul; Moon, Dae-Sik; Yoon, Sung-Chul; Raymond, John C

    2013-01-01

    Phosphorus ($^{31}$P), which is essential for life, is thought to be synthesized in massive stars and dispersed into interstellar space when these stars explode as supernovae (SNe). Here we report on near-infrared spectroscopic observations of the young SN remnant Cassiopeia A, which show that the abundance ratio of phosphorus to the major nucleosynthetic product iron ($^{56}$Fe) in SN material is up to 100 times the average ratio of the Milky Way, confirming that phosphorus is produced in SNe. The observed range is compatible with predictions from SN nucleosynthetic models but not with the scenario in which the chemical elements in the inner SN layers are completely mixed by hydrodynamic instabilities during the explosion.

  9. Phosphorus in the young supernova remnant Cassiopeia A.

    PubMed

    Koo, Bon-Chul; Lee, Yong-Hyun; Moon, Dae-Sik; Yoon, Sung-Chul; Raymond, John C

    2013-12-13

    Phosphorus ((31)P), which is essential for life, is thought to be synthesized in massive stars and dispersed into interstellar space when these stars explode as supernovae (SNe). Here, we report on near-infrared spectroscopic observations of the young SN remnant Cassiopeia A, which show that the abundance ratio of phosphorus to the major nucleosynthetic product iron ((56)Fe) in SN material is up to 100 times the average ratio of the Milky Way, confirming that phosphorus is produced in SNe. The observed range is compatible with predictions from SN nucleosynthetic models but not with the scenario in which the chemical elements in the inner SN layers are completely mixed by hydrodynamic instabilities during the explosion. PMID:24337291

  10. Speciation of Phosphorus by coupled HPLC-ICPMS: Application for quantification of reduced forms of phosphorus in rocks and natural waters.

    NASA Astrophysics Data System (ADS)

    Atlas, Z. D.; Pasek, M. A.; Sampson, J.

    2014-12-01

    Phosphorus is a geologically important element making up approximately 0.12 % of the Earth's crust. It is commonly found as relatively insoluble apatite and this causes phosphorus to be a limiting nutrient in biologic processes. Despite this, phosphorus is a key element in DNA, RNA and other cellular materials. Recent works suggest that reduced phosphorus played a substantial role in the development of life on the early Earth. Reduced phosphorus is considerably more soluble than oxidized phosphorus, and reduced phosphorus may continue to play a role in biologic productivity. This study examines a new methodology for quantification of reduced phosphorus separated by coupled HPLC - ICP-MS. We show that phosphorus species (P1+, P3+ and P5+) are cleanly separated in the HPLC and coupled with the ICP-MS reaction cell (using O2 gas) effectively convert elemental P to P-O producing lower background and flatter baseline chromatography. Results suggest very low detection limits (0.05 mM) for P species analyzed as P-O at M/Z = 47. Additionally this technique has potential to speciate at least 5 other metastable forms of phosphorus. We verified this method on numerous materials including leached Archean rocks to suburban retention pond waters and many samples show small but detectible levels of reduced phosphorus. These data highlight a significant role of redox processing of phosphorus throughout the history of the Earth, with the reduced oxidation state phosphorus compounds, phosphite and hypophosphite, potentially acting as significant constituents in the anaerobic environment.

  11. Degradation Mechanisms of SOFC Anodes in Coal Gas Containing Phosphorus

    SciTech Connect

    Marina, Olga A.; Coyle, Christopher A.; Thomsen, Edwin C.; Edwards, Danny J.; Coffey, Greg W.; Pederson, Larry R.

    2010-01-22

    The interaction of phosphorus in synthetic coal gas with the nickel-based anode of solid oxide fuel cells has been investigated. Tests with both anode-supported and electrolyte-supported button cells were performed at 700 to 800oC in synthetic coal gas containing 0.5 to 10 ppm phosphorus, introduced as phosphine. Two primary modes of degradation were observed. The most obvious was the formation of a series of bulk nickel phosphide phases, of which Ni3P, Ni5P2, Ni12P5 and Ni2P were identified. Phosphorus was essentially completely captured by the anode, forming a sharp boundary between converted and unconverted anode portions. These products partially coalesced into large grains, which eventually affected electronic percolation through the anode support. Thermodynamic calculations predict that formation of the first binary nickel phosphide phase is possible at sub-parts per billion concentrations in coal gas at temperatures relevant to fuel cell operation. A second mode of degradation is attributed to surface diffusion of phosphorus to the active anode/electrolyte interface to form an adsorption layer. Direct evidence for the presence of such an adsorption layer on nickel was obtained by surface spectroscopies on fracture surfaces. Further, cell performance losses were observed well before the entire anode was converted to bulk nickel phosphide. Impedance spectroscopy revealed that these losses were primarily due to growth in electrodic resistance, whereas large ohmic increases were visible when the entire anode was converted to nickel phosphide phases. The rate of resistance growth for anode-supported cells showed a very low dependence on phosphorus concentration, attributed to phosphorus activity control within the anode by bulk nickel phosphide products.

  12. PREDICTING CONCENTRATION OF TOTAL PHOSPHORUS AND CHLOROPHYLL 'A' IN A LAKE WITH SHORT HYDRAULIC RESIDENCE TIME

    EPA Science Inventory

    The relationship between total phosphorus and chlorophyll a concentration was determined for Skinner Lake, Indiana over an annual cycle in 1978-79. Total nitrogen: total phosphorus ratios in the epilimnion ranged from 19 to 220 suggesting a phosphorus-dependent algal yield in the...

  13. Increased plant growth from nitrogen addition should conserve phosphorus in terrestrial ecosystems

    E-print Network

    processes. nitrogen cycle nitrogen inputs phosphorus cycle phosphorus retention Human activities have causedIncreased plant growth from nitrogen addition should conserve phosphorus in terrestrial ecosystems, 2007) Inputs of available nitrogen (N) to ecosystems have grown over the recent past. There is limited

  14. Phosphorus and arsenic profile control for high performance epitaxial base bipolar junction devices

    E-print Network

    Bashir, Rashid

    Phosphorus and arsenic profile control for high performance epitaxial base bipolar junction devices interface. The arsenic segregation is confirmed to be significantly higher than phosphorus. In addition, an increase in both the phosphorus and arsenic incorporation is observed in the presence of a highly doped

  15. Phosphorus removal from municipal wastewater in an experimental two-stage vertical flow constructed wetland

    E-print Network

    Brix, Hans

    wetland systems to enhance phosphorus removal, and identified a calcite product, which is commerciallyPhosphorus removal from municipal wastewater in an experimental two-stage vertical flow constructed may be used in separate, exchangeable filter units in constructed wetland systems to remove phosphorus

  16. IMPACT OF ALGAL-AVAILABLE PHOSPHORUS ON LAKE ERIE WATER QUALITY: MATHEMATICAL MODELING

    EPA Science Inventory

    Accurate estimates of the forms and bioavailability of phosphorus loadings are necessary for loading trend analysis and water quality model development. Total phosphorus loading data for Lake Erie from 1970 to 1980 were categorized into three forms, based on phosphorus bioavailab...

  17. Anthropogenic phosphorus flows under different scenarios for the city of Stockholm, Sweden.

    PubMed

    Wu, Jiechen; Franzén, Daniel; Malmström, Maria E

    2016-01-15

    Today, concerns prevail about the unsustainable use of phosphorus and worldwide eutrophication, thus requiring efficient management of phosphorus flows. With increasing population and associated urban growth, urban management of phosphorus flows in the perspectives of recycling, eutrophication and total budget becomes increasingly important. This study mapped phosphorus flows for a reference year (2013) and a future year (2030) using different scenarios for the city of Stockholm, Sweden. The results indicated that the Swedish goal of recycling phosphorus from wastewater would cover the majority of the total phosphorus budget for Stockholm. However, in 2013, only 10% of phosphorus was recycled for agricultural use, around half of which was from sewage sludge and the other half from food waste. Almost 50% of total phosphorus was sent to landfill/mining waste capping with sewage sludge, for economic reasons and lack of market. Among the scenarios of upstream and downstream urban management options studied in combination with population growth, recovery of phosphorus from sewage sludge had the greatest potential to increase the fraction recycled to agriculture. However, only upstream measures, e.g. changed diet, were able to reduce the total phosphorus budget. Urban management of phosphorus flows based on the different perspectives of recycling, eutrophication or total budget was shown to potentially result in different preferred management actions and both upstream and downstream measures need to be considered. Moreover, management needs to pay attention to small but environmentally sensitive flows, particularly when setting city goals on phosphorus recycling by percentage in a large budget. PMID:26442719

  18. Effects of Phosphorus on Morphology of Hydroponically Grown Scaevola aemula R. Br. "Whirlwind Blue"

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The popular hanging basket plant, fan-flower (Scaevola aemula R. Br. ‘Whirlwind Blue’), is cultivated from low phosphorus soils and requires minimal supplemental phosphorus. To accurately evaluate the effects of phosphorus on morphology, fan-flower was grown hydroponically in order to maintain conc...

  19. Phosphorus concentration and loading reductions following changes in fertilizer application and formulation on managed turf

    Technology Transfer Automated Retrieval System (TEKTRAN)

    All current and future efforts to address water quality impairment must focus on phosphorus. Phosphorus is a natural element in the environment and is an essential element of all life. However, excess phosphorus, particularly in surface waters can lead to severe eutrophication. Identifying source ar...

  20. Technology for recovery of phosphorus from animal wastewater through calcium phosphate precipitation

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A wastewater treatment process was developed for removal of phosphorus from livestock wastewater. The phosphorus is recovered as calcium phosphate with addition of only small quantities of liquid lime. The process is based on the distinct chemical equilibrium between phosphorus and calcium ions when...

  1. Polarization-sensitive broadband photodetector using a black phosphorus vertical pn junction

    E-print Network

    Cui, Yi

    Polarization-sensitive broadband photodetector using a black phosphorus vertical p­n junction a layered black phosphorus transistor that is polarization-sensitive over a bandwidth from 400 nm to 3 dichroism photodetection. The use of anisotropic layered black phosphorus in polarization- sensitive

  2. Transport properties of pristine few-layer black phosphorus by van der Waals

    E-print Network

    Yao, Shao Q

    Transport properties of pristine few-layer black phosphorus by van der Waals passivation- layer sheet of perfectly arranged and tightly bound carbon or phosphorus atoms. And while graphene of phosphorene research was the natural tendency of the phosphorus atoms to react with the surrounding air, which

  3. Land Application of Wastes: An Educational Program. Phosphorus Considerations - Module 19, Objectives, and Script.

    ERIC Educational Resources Information Center

    Clarkson, W. W.; And Others

    The treatment of wastewater phosphorus via land application includes both chemical and biological mechanisms. Chemically, phosphorus reacts with iron, aluminum, and calcium compounds in the soil providing efficient removal over a wide range of pH values. Phosphorus is also absorbed by rooted plants which, upon harvest, constitute a further removal…

  4. Using extension phosphorus uptake research to improve Idaho's nutrient management planning program

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Irrigated silage corn is the main crop used for phosphorus removal; however little is known about the actual amounts of phosphorus removed under southern Idaho growing conditions. The purpose of this study was to survey phosphorus removal by irrigated corn grown for silage in southern Idaho under va...

  5. Effects of phosphorus implantation and subsequent growth on diamond Euo Sik Choa,*, Cheon An Leea

    E-print Network

    Lee, Jong Duk

    Effects of phosphorus implantation and subsequent growth on diamond Euo Sik Choa,*, Cheon An Leea of diamond, phosphorus implantation was done during the growth of diamond films. The diamond films implanted with phosphorus were subsequently grown again by microwave plasma chemical vapor deposition (MPCVD). Fabricated

  6. Segregation of phosphorus to ferrite grain boundaries during transformation in FeP alloy

    E-print Network

    Cambridge, University of

    Segregation of phosphorus to ferrite grain boundaries during transformation in Fe­P alloy Jeong A binary alloy of iron containing 0.17 wt% of phosphorus has been heat- treated under a variety of conditions in order to see whether the segregation of phosphorus to grain boundaries can be controlled

  7. Planktonic phosphorus pool sizes and cycling efficiency in coastal and interior British Columbia lakes

    E-print Network

    Mazumder, Asit

    Planktonic phosphorus pool sizes and cycling efficiency in coastal and interior British Columbia long acknowledged the importance of phosphorus (P) in determining the organism biomass and productivity of precise measurements of the dissolved inorganic phosphorus (PO3À 4 ) and (2) accurate or complete

  8. Properties of phosphorus compounds by density functional theory: CH3P species as a test case

    E-print Network

    Nguyen, Minh Tho

    Properties of phosphorus compounds by density functional theory: CH3P species as a test case Minh and energetic properties of low-coordinated phosphorus compounds is reported. While DFT methods include both assessment and in connection with our continuing theoretical study of low- coordinated phosphorus compounds

  9. Response to Phosphorus Limitation Varies among Lake Populations of the Freshwater Snail Potamopyrgus

    E-print Network

    Neiman, Maurine

    Response to Phosphorus Limitation Varies among Lake Populations of the Freshwater Snail. As an initial step to determining whether P. antipodarum are also locally adapted to phosphorus availability, we examined whether populations differ in their responses to phosphorus limitation. We found that field

  10. The LPB1 Gene Is Important for Acclimation of Chlamydomonas reinhardtii to Phosphorus

    E-print Network

    Wykoff, Dennis D.

    The LPB1 Gene Is Important for Acclimation of Chlamydomonas reinhardtii to Phosphorus and Sulfur of these responses are specific for phosphorus limitation, including responses that enable cells to efficiently than wild- type cells during phosphorus limitation. The responses of this mutant to nitrogen limitation

  11. Anomalous Quantum Transport Properties in Semimetallic Black Phosphorus

    NASA Astrophysics Data System (ADS)

    Akiba, Kazuto; Miyake, Astushi; Akahama, Yuichi; Matsubayashi, Kazuyuki; Uwatoko, Yoshiya; Arai, Hayato; Fuseya, Yuki; Tokunaga, Masashi

    2015-07-01

    Magnetoresistance in single crystals of black phosphorus is studied at ambient and hydrostatic pressures. In the semiconducting states at pressures below 0.71 GPa, the magnetoresistance shows periodic oscillations, which can be ascribed to the magneto-phonon resonance that is characteristic of high-mobility semiconductors. In the semimetallic state above 1.64 GPa, both transverse and longitudinal magnetoresistances show a considerable increase while exhibiting superposed Shubnikov-de Haas oscillations. The observed small Fermi surfaces, high mobilities, and light effective masses of carriers in semimetallic black phosphorus are comparable to those in the representative elemental semimetals of bismuth and graphite.

  12. Fire-resistant phosphorus containing polyimides and copolyimides

    NASA Technical Reports Server (NTRS)

    Mikroyannidis, J. A. (inventor)

    1985-01-01

    Phosphorus-containing polyimides and copolyimides are synthesized in a two-step polycondensation reaction from 1- (diorganooxyphosphonl)methly 2,4- and 2,6-diaminobenzenes and tetracarboxylic anhydride. The diorgano position of the diorganooxyphosphonyl group includes alkyl, such as ethyl, substituted alkyl, such as 2-chloroethyl, and aryl such as phenyl. The tetracarboxylic anhydries include compounds such as pyrometallitic dianhydride and benzophenone tetracarboxylic dianhydride. The glass transition temperature (Tg) of the polyimides is reduced by incorporation of the (dialkoxyphosphonyl)methyl groups. The phosphorus-containing copolyimides show a considerably higher degree of fire-resistance as compared to that of the corresponding common polyimides.

  13. 33 CFR 64.33 - Marking by the Coast Guard.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ...2011-07-01 false Marking by the Coast Guard. 64.33 Section 64.33 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY...Provisions § 64.33 Marking by the Coast Guard. (a) The District...

  14. 33 CFR 64.33 - Marking by the Coast Guard.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ...2012-07-01 false Marking by the Coast Guard. 64.33 Section 64.33 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY...Provisions § 64.33 Marking by the Coast Guard. (a) The District...

  15. 33 CFR 64.33 - Marking by the Coast Guard.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ...2013-07-01 false Marking by the Coast Guard. 64.33 Section 64.33 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY...Provisions § 64.33 Marking by the Coast Guard. (a) The District...

  16. 33 CFR 64.33 - Marking by the Coast Guard.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ...2014-07-01 false Marking by the Coast Guard. 64.33 Section 64.33 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY...Provisions § 64.33 Marking by the Coast Guard. (a) The District...

  17. 33 CFR 64.33 - Marking by the Coast Guard.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ...2010-07-01 false Marking by the Coast Guard. 64.33 Section 64.33 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY...Provisions § 64.33 Marking by the Coast Guard. (a) The District...

  18. Evaluation of phosphorus source coefficients as predictors of runoff phosphorus concentrations.

    PubMed

    Smith, Matt C; White, John W; Coale, Frank J

    2009-01-01

    Many states have adopted a P site index (PSI) as a risk assessment tool to determine when P-based nutrient management is required for a given agricultural field. Some PSIs use a weighting factor, the phosphorus source coefficient (PSC), to account for differences in P solubility between organic P sources. Information relating to appropriate values of PSC for various organic P sources is limited. The objectives of this study were to determine PSCs for organic P sources and to examine the relationship between PSCs and P concentrations measured in simulated rainfall runoff. An incubation study was used to calculate PSCs based on the extractability of P from organic P sources (separated and unseparated liquid dairy manure, digested dairy manure, dairy manure solids, poultry litter, and compost) relative to P from triple superphosphate fertilizer. The PSCs from the 14-d incubations were the best predictors of runoff P after 14 d soil equilibration in the runoff boxes. The values for iron-oxide strip phosphorus (FeO-P) PSC ranged from 78% for compost to 28% for poultry litter and were significantly related to runoff DR-P (r(2) = 0.80***) and FeO-P (r(2) = 0.76***) during the 14-d runoff event. Mehlich 3 PSCs ranged from 59% for compost to 30% for unseparated dairy manure and were better predictors of DR-P and FeO-P during the 56-d event (r(2) = 0.73*** and 0.65***, respectively). The results of this study indicate that PSCs based on soil incubations may improve the ability of PSCs to predict the risk of runoff transport, particularly after manure incorporation. PMID:19202029

  19. Probing Phosphorus Efficient Low Phytic Acid Content Soybean Genotypes with Phosphorus Starvation in Hydroponics Growth System.

    PubMed

    Kumar, Varun; Singh, Tiratha Raj; Hada, Alkesh; Jolly, Monica; Ganapathi, Andy; Sachdev, Archana

    2015-10-01

    Phosphorus is an essential nutrient required for soybean growth but is bound in phytic acid which causes negative effects on both the environment as well as the animal nutrition. Lowering of phytic acid levels is associated with reduced agronomic characteristics, and relatively little information is available on the response of soybean plants to phosphorus (P) starvation. In this study, we evaluated the effects of different P starvation concentrations on the phytic acid content, growth, and yield of seven mutant genotypes along with the unirradiated control, JS-335, in a hydroponics growth system. The low phytic acid containing mutant genotypes, IR-JS-101, IR-DS-118, and IR-V-101, showed a relatively high growth rate in low P concentration containing nutrient solution (2 ?M), whereas the high P concentration (50 ?M) favored the growth of IR-DS-111 and IR-DS-115 mutant genotypes containing moderate phytate levels. The mutant genotypes with high phytic acid content, IR-DS-122, IR-DS-114, and JS-335, responded well under P starvation and did not have any significant effect on the growth and yield of plants. Moreover, the reduction of P concentration in nutrient solution from 50 to 2 ?M also reduced the phytic acid content in the seeds of all the soybean genotypes under study. The desirable agronomic performance of low phytic acid containing mutant genotype IR-DS-118 reported in this study suggested it to be a P-efficient genotype which could be considered for agricultural practices under P limiting soils. PMID:26239443

  20. [Study on the nitrogen and phosphorus uptake ability of four plants cultivated on floating-bed].

    PubMed

    Wu, Jian-Qiang; Wang, Min; Wu, Jian; Jiang, Yue; Sun, Cong-Jun; Cao, Yong

    2011-04-01

    Plant floating-bed tested engineering was constructed for eutrophication control in Dian-shan Lake, the characteristics and nutrient uptake abilities of Canna indica, Iris pseudacorus, Thalia dealbata and Lythrum salicaria were compared. It shows that using upper and lower nylon nets to fix the plants on the floating-bed is beneficial for them to grow and reproduce rapidly. Survival rates of Canna indica, lris pseudacorus, Thalia dealbata and Lythrum salicaria are 83.33%, 83.33%, 76.67% and 53.33% respectively. Ramets of Canna indica and Thalia dealbata are 64 and 78 respectively in November, and the biomass (fresh weight) of these two plants are 32.0 and 38.6 kg per individual plant. Nitrogen (N) and phosphorus (P) content in stems/leaves of Canna indica and Thalia dealbata are greater than those in roots. The ratio between stems/leaves and roots of N, P content in Canna indica are 1.40 and 1.21 respectively, while 1.59 and 1.08 in Thalia dealbata. The difference of cumulative N, P content in plants is mostly on account of different plant biomass. N uptake ability of Thalia dealbata is the highest, which is 457.11 g per square; Canna indica has the highest P uptake ability, which is 41.29 g per square. N, P uptake ability of stems/leaves in Canna indica are 2.17 and 1.86 times higher than that of roots, while 1.73 and 1.17 times higher respectively in Thalia dealbata. Thus, Canna indica and Thalia dealbata are recommended as the floating-bed plants to control the eutrophication in Dian-shan Lake. PMID:21717738

  1. The X-33 Program Update

    NASA Technical Reports Server (NTRS)

    Dill, Charlie

    2000-01-01

    This viewgraph presentation gives an overview of the X-33 program update, including details on program objectives and plans, the X-33 configuration, technologies used, and X-33 assembly and test status.

  2. Composite of graphite/phosphorus as anode for lithium-ion batteries

    NASA Astrophysics Data System (ADS)

    Bai, Aojun; Wang, Li; Li, Jiaoyang; He, Xiangming; Wang, Jixian; Wang, Jianlong

    2015-09-01

    Graphite/Phosphorus composite anodes are prepared by mixing graphite and the phosphorus/carbon material, which prepared by heating the mixture of red phosphorus and porous carbon. Their electrochemical performances are evaluated as anodes for Li-ion batteries. A graphite/Phosphorus composite|LiFePO4 full-cell is also attempted. When the phosphorus/carbon content in the composite anode is 28.6 wt.%, the composite anode presents high reversible capacity of 500 mAh g-1 and considerable cycleability comparable to that of graphite anode, showing promising performance.

  3. Beneficial effect of phosphorus on the creep behavior of Inconel 718

    SciTech Connect

    Song, H.; Guo, S.; Hu, Z. . Inst. of Metal Research)

    1999-06-18

    Phosphorus has long been regarded as a harmful impurity in superalloys. However, recent research work has found that phosphorus within a proper content range could remarkably improve the stress-rupture properties of some superalloys. In order to study the individual effects of phosphorus alone, two INCONEL 718 based alloys, with 0.003 wt% and 0.02 wt% phosphorus, respectively, have been prepared in the present work and the creep properties at different temperature and under different stress levels have been carefully determined. This is the first publication about the individual effect of phosphorus alone on the creep parameters (stress exponent and activation energy) of superalloys.

  4. A TOOL FOR ASSESSING BMP EFFECTIVENESS FOR PHOSPHORUS POLLUTION CONTROL

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A Best Management Practice (BMP) assessment tool was developed as a part of an effort to address the phosphorus (P) pollution and associated eutrophication problem affecting the Cannonsville Reservoir, part of the New York City water supply system. P reaching the reservoir is thought to emanate fro...

  5. EFFECTS OF DRYING ON PHOSPHORUS DISTRIBUTION IN POULTRY MANURE

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Laboratory drying may alter manure phosphorus (P) distribution. We examined effects of freeze-, air (22oC)-, and oven (65oC)-drying on sequentially fractioned poultry manure P. Higher drying temperatures resulted in lower percent dry matter. Increased H2O- and decreased NaHCO3-extractable P with ...

  6. Soil phosphorus and potassium estimation by reflectance spectroscopy

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Visible and near infrared (VNIR) diffuse reflectance spectroscopy has potential in site-specific measurement of soil properties. However, previous studies have reported VNIR estimates of plant available soil phosphorus (P) and potassium (K) to be of variable accuracy. In this study, we used a databa...

  7. Phosphorus nuclear magnetic resonance in isolated perfused rat pancreas

    SciTech Connect

    Matsumoto, Takehisa; Kanno, Tomio; Seo, Yoshiteru; Murakami, Masataka; Watari, Hiroshi National Institute for Physiological Sciences, Okazaki )

    1988-04-01

    Phosphorus nuclear magnetic resonance spectroscopy was applied to measure phosphorus energy metabolites in isolated perfused rat pancreas. The gland was perfused with a modified Krebs-Henseleit solution at room temperature (25{degree}C). {sup 31}P resonances of creatine phosphate (PCr), ATP, ADP, inorganic phosphate (P{sub i}) and phosphomonoesters (PMEs) were observed in all the preparations of pancreas. In different individual preparations, the resonance of PCr varied, but those of ATP were almost the same. The initial levels of PCr and ATP in individual preparations, however, remained almost unchanged during perfusion with the standard solution for 2 h. When the perfusion was stopped, the levels of ATP and PCr decreased, while the levels of PME and P{sub i} increased. At that time, the P{sub i} resonance shfted to a higher magnetic field, indicating that the tissue pH decreased. On reperfusion, the tissue levels of phosphorus compounds and the tissue pH were restored to their initial resting levels. Continuous infusion of 0.1 {mu}M acetylcholine caused marked and sustained increases in the flow of pancreatic juice and protein output. During the stimulation the tissue levels of phosphorus compounds remained unchanged, while the tissue pH was decreased slightly.

  8. Contributions of systematic tile drainage to watershed scale phosphorus transport

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Phosphorus (P) transport from agricultural fields continues be a focal point for addressing harmful algal blooms (HABs) and nuisance algae in freshwater systems throughout the world. In humid, poorly drained regions, attention has turned to P delivery through subsurface tile drainage. Research on th...

  9. A Hybrid Phosphorus Ligand for Highly Enantioselective Asymmetric Hydroformylation

    E-print Network

    Zhang, Xumu

    A Hybrid Phosphorus Ligand for Highly Enantioselective Asymmetric Hydroformylation Yongjun Yan enantioselectivities (up to 99% ee) have been achieved in the Rh-catalyzed asymmetric hydroformylations of styrene derivatives and vinyl acetate. Introduction Hydroformylation is the reaction of alkenes with carbon monoxide

  10. LIVESTOCK GRAZING IMPACTS ON PHOSPHORUS IN A CARBONATE SPRING

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Dissolved phosphorus loads in Appalachian River basins are directly related to the amount of land drained by carbonate aquifers. Typically, carbonate aquifers in Appalachia are characterized by a high secondary permeability associated with solutionally enlarged fractures and joints in the soluble b...

  11. RESEARCH ARTICLE Sulfur-induced changes in phosphorus distribution

    E-print Network

    Florida, University of

    RESEARCH ARTICLE Sulfur-induced changes in phosphorus distribution in Everglades Agricultural Area. Soils were sampled four times during the growing season at 2, 6, 9, and 13 months after sulfur application and sub- jected to chemical P fractionation. Sulfur application had minimal effect on soil p

  12. A Systematic Presentation of Organic Phosphorus and Sulfur Compounds.

    ERIC Educational Resources Information Center

    Hendrickson, James B.

    1985-01-01

    Because the names, interrelations, and oxidation levels of the organic compounds of phosphorus and sulfur tend to confuse students, a simple way to organize these compounds has been developed. The system consists of grouping them by oxidation state and extent of carbon substitution. (JN)

  13. Phosphorus Loading Trends in Lake Michigan: A Historic Surprise

    EPA Science Inventory

    Total phosphorus (TP) loads to the Great Lakes have been of interest to researchers since the 1960s. The International Joint Commission (IJC) was the primary source of Great Lakes TP loading data during the 1970s and 1980s when the IJC released annual reports detailing Great Lake...

  14. PHOSPHORUS AVAILABILITY TO SUGARCANE IN HISTOSOLS UNDER PERIODIC FLOODING

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Subsidence of organic soils and phosphorus (P) release into surface water are two major issues facing agriculture in the Everglades Agricultural Area in south Florida. Raising the water table depth and periodic flooding may reduce the rate of oxidation of these soils. This study was conducted to qua...

  15. PRECIPITATION AND INACTIVATION OF PHOSPHORUS AS A LAKE RESTORATION TECHNIQUE

    EPA Science Inventory

    Many eutrophic lakes respond slowly following nutrient diversion because of long water retention times, and the recycling of phosphorus from sediments and other internal sources. Treatment of lakes with aluminum sulfate and/or sodium aluminate is a successful method for removing ...

  16. Phosphorus and calcium retention in serially harvested cattle

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Data from 3 serial harvest trials were utilized to calculate phosphorus and calcium retention in cattle. Trial 1 evaluated three rates of gain during a growing period followed by a common finishing diet utilizing British crossbred steers. Four steers were harvested from each treatment following th...

  17. PREDICTING MANAGEMENT EFFECTS ON PHOSPHORUS LOSS FROM FARMING SYSTEMS

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A process-level soil phosphorus (P) model including surface and subsurface components was developed and incorporated into the Integrated Farm System Model (IFSM). Preliminary evaluation indicated that the model accurately predicted soluble P losses, but under-predicted total P losses due to under-pr...

  18. Divergent Selection for Phosphorus Concentration in Orchardgrass and Reed Canarygrass

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Phosphorus is a vital nonrenewable natural resource that is essential for plant and animal growth. Grass swards and/or buffer strips can be utilized to reduce P losses that occur by soil erosion, surface runoff, or leaching. The objective of this study was to conduct one cycle of divergent selectio...

  19. Options for Reducing Erosion and Phosphorus Movement in Potato Systems

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Soil erosion and phosphorus (P) runoff can be severe in potato production systems in the Northeast U.S., which are characterized by intensive tillage, minimal ground cover, low crop residue return, and steep slopes. We used rainfall simulators in the greenhouse and field to assess sediment and P mov...

  20. Development and testing of a new phosphorus index for Kentucky

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The phosphorus index (PI) is a tool developed by USDA-NRCS to evaluate a field’s risk of P loss and has been adopted by most states, including KY, in their 590 Nutrient Management Standard. USDA-NRCS recently revised their 590 Standard, now requiring that states test the accuracy of their PI against...

  1. Seasonal and long term changes in manure phosphorus availability

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Soils are most often the resource used in the final assimilation of many agricultural waste products. In regions where manure phosphorus (P) production exceeds the assimilative capacity of crops, soil P will often accumulate at high levels. Land application of manure at rates exceeding crop removal ...

  2. PHOSPHORUS FEEDING AND MANURE NUTRIENT RECYCLING ON WISCONSIN DAIRY FARMS

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Nutrient management regulations for livestock operations are focused on a farm¿s ability to recycle the phosphorus (P) contained in manure. Most efforts to improve dairy manure management emphasize manure handling, storage, and land application techniques. Little is known about relationships betwee...

  3. Effect of Animal Manure on Phosphorus Sorption to Soils

    Technology Transfer Automated Retrieval System (TEKTRAN)

    In most phosphorus (P) sorption studies P is added as an inorganic salt to a pre-defined background solution such as CaCl2 or KCl; however, in many regions the application of P to agricultural fields is in the form of animal manure. The purpose of this study, therefore, was to compare the sorption b...

  4. Dairy heifer diets, manure management, and runoff phosphorus

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Manure application to cropland can contribute to runoff losses of phosphorus and eutrophication of surface waters. We conducted a series of three rainfall simulation experiments to assess the effects of dairy heifer diet P, manure incorporation, application rate, and soil test P on runoff P losses f...

  5. UPTAKE, TRANSLOCATION AND RELEASE OF PHOSPHORUS BY 'ELODEA DENSA'

    EPA Science Inventory

    Short-term (16h) laboratory studies of 32p uptake by Elodea densa rooted in sediment demonstrated both foliar and root uptake, and that translocation occurred acropetally and basipetally. Root absorption is projected to provide 83-85% of total phosphorus uptake during 12-16th pho...

  6. EFFECTS OF FORAGE MANAGEMENT ON PASTURE PRODUCTIVITY AND PHOSPHORUS CONTENT

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The objectives of the current study were to determine the amounts of above- and below-ground plant biomass production, phosphorus (P) uptake by forage, and P concentration of cool-season grass forage as influenced by management and season. Five forage management treatments were evaluated over three...

  7. Forms and Bioavailability of Phosphorus Associated With Natural Organic Matter

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Natural organic matter (NOM) is an important ingredient in soil which can improve physical, chemical, and biological properties of soils and nutrient supplies. In this study, we investigated the spectral features and potential availability of phosphorus (P) in the IHSS Elliott Soil humic acid standa...

  8. Soil controls of phosphorus runoff: management barriers and opportunities

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The persistent problem of eutrophication, the biological enrichment of surface waters akin to aging, has produced a vast literature on soil phosphorus (P) effects on runoff water quality. This paper considers the mechanisms controlling soil P transfers from agricultural soils to runoff waters, highl...

  9. Struvite precipitation and phosphorus removal using magnesium sacrificial anode.

    PubMed

    Kruk, Damian J; Elektorowicz, Maria; Oleszkiewicz, Jan A

    2014-04-01

    Struvite precipitation using magnesium sacrificial anode as the only source of magnesium is presented. High-purity magnesium alloy cast anode was found to be very effective in recovery of high-quality struvite from water solutions and from supernatant of fermented waste activated sludge from a wastewater treatment plant that does not practice enhanced biological phosphorus removal. Struvite purity was strongly dependent on the pH and the electric current density. Optimum pH of the 24 mM phosphorus and 46 mM ammonia solution (1:1.9 P:N ratio) was in the broad range between 7.5 and 9.3, with struvite purity exceeding 90%. Increasing the current density resulted in elevated struvite purity. No upper limits were observed in the studied current range of 0.05-0.2 A. Phosphorus removal rate was proportional to the current density and comparable for tests with water solutions and with the supernatant from fermented sludge. The highest P-removal rate achieved was 4.0 mg PO4-P cm(-2) h(-1) at electric current density of 45 A m(-2). Initial substrate concentrations affected the rate of phosphorus removal. The precipitated struvite accumulated in bulk liquid with significant portions attached to the anode surface from which regular detachment occurred. PMID:24387911

  10. Response of Forage Chicory Seedlings to Available Soil Phosphorus

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Phosphorus fertility may be responsible for observed differences in chemical composition of forage chicory (Cichorium intybus L.) on West Virginia and Pennsylvania soils, but P effects on chicory growth on these soils are unclear. We evaluated the effect of available soil P (ASP) on ‘Puna’, ‘Lacert...

  11. Total Phosphorus Mass Balance Models for the Lower Boise River

    USGS Multimedia Gallery

    USGS hydrologic technician Alvin Sablan calibrates an acoustic Doppler current profiler before collecting a discharge measurement on the Boise River near Caldwell, Idaho. The discharge measurement and other data were used to develop total phosphorus mass balance models for the lower Boise River. The...

  12. PHOSPHORUS EXCRETION FROM RUMINANTS IMPLANTED WITH ESTROGENIC GROWTH IMPLANTS

    Technology Transfer Automated Retrieval System (TEKTRAN)

    When collected, most beef cattle feedyard manure has a nitrogen:phosphorus ratio of about 2:1. Unfortunately, most plants prefer a N:P ratio of about 5:1. If the amount of P in the manure could be decreased, feedyard manure would be a more acceptable and valuable fertilizer for farmers. One way ...

  13. ALTERNATIVE TREATMENT AND RECOVERY OF PHOSPHORUS FROM ANAEROBIC LAGOONS

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Manure nutrients in excess of the assimilative capacity of land available on farms are an environmental concern often associated with confined animal feeding operations (CAFO). The ability to extract phosphorus (P) from lagoon wastewater is critical to accomplish CAFO's comprehensive nutrient manage...

  14. IDENTIFYING TOTAL PHOSPHORUS SPECTRAL SIGNAL IN A TROPICAL ESTUARY LAGOON

    E-print Network

    Gilbes, Fernando

    IDENTIFYING TOTAL PHOSPHORUS SPECTRAL SIGNAL IN A TROPICAL ESTUARY LAGOON USING AN HYPERSPECTRAL __________________ Date #12;II ABSTRACT The San Jose Lagoon (SJL) is located in the northern coast of Puerto Rico in eutrophic tropical lagoons though a hyperspectral sensor. Its use in water quality model #12;III validation

  15. Module for phosphorus separation and recycling from liquid manures

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A method has been developed to extract and concentrate soluble phosphates from livestock wastewater. The research was conducted over a 10-year period and went from initial bench studies and discovery, to pilot module development, to full-scale demonstrations of the phosphorus (P) module in swine fa...

  16. Sorption of Phosphorus from Swine, Dairy, and Poultry Manures

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Sorption studies are commonly used to obtain important parameters controlling the fate of phosphorus (P) in the environment. In most cases P is added as an inorganic salt to a pre-defined background solution such as CaCl2. The limitation to this type of study, however, is that the application of P ...

  17. ENZYMATIC HYDROLYSIS OF ORGANIC PHOSPHORUS IN ANIMAL MANURE

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Information is needed on the contribution of organic polyphosphate phytate to the sources and sinks of dissolved phosphorus in the soil-manure-water system that is often associated with water quality degradation in watersheds with confined animal feeding operations. Effects of Na+, Ca2+, Al3+, and ...

  18. Direct Speciation of Phosphorus in Alum-Amended Poultry Litter

    E-print Network

    Sparks, Donald L.

    Direct Speciation of Phosphorus in Alum-Amended Poultry Litter: Solid-State 31 P NMR Investigation, and Department of Plant and Soil Sciences, University of Delaware, Newark, Delaware 19717 Amending poultry litter prerequisite for the assessment of the sustainability of intensive poultry operations. Both solid- state MAS

  19. SORPTION OF ORGANIC PHOSPHORUS COMPOUNDS IN ATLANTIC COASTAL PLAIN SOILS

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Organic phosphorus (P) can comprise a significant amount of the total P in animal wastes, yet there is little information on the potential for organic P to be transferred from soils to watercourses. We examined the adsorption of organic P compounds to soils typical of the Southeastern U.S., i.e. Bl...

  20. Effects of poultry manure on phosphorus availability to perennial ryegrass

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Soil phosphorus (P) exists in numerous forms that differ in plant availability. High-P organic fertilizers, including poultry manure (PM), can alter the balance of these soil P forms and may affect plant nutrient status. To investigate the effects of PM on soil P distribution and plant utilization...

  1. 21 CFR 862.1580 - Phosphorus (inorganic) test system.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Phosphorus (inorganic) test system. 862.1580 Section 862.1580 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES CLINICAL CHEMISTRY AND CLINICAL TOXICOLOGY DEVICES Clinical Chemistry...

  2. Yield and persistence response of forage chicory to phosphorus fertility

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Forage chicory (Cichorium intybus) is a productive plant that appears particularly well suited to improving summer yield of pastures in the USA. Poor palatability of some chicory cultivars in locations with low soil phosphorus fertility has been linked to high levels of sesquiterpene lactone, a bit...

  3. REDUCTION OF HIGH SOIL TEST PHOSPHORUS BY CROP REMOVAL

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Soils with high phosphorus (P) level can contribute to excess P in runoff. The objectives of this study were to evaluate crop P removal effects on soil P reduction and to evaluate various corn hybrids and soybean varieties for differences in P removal. Soil with varying P level as a result of beef c...

  4. NITROGEN AND PHOSPHORUS BASED MANURE OR COMPOST APPLICATION

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Composted and non-composted beef cattle feedlot manure were applied based on nitrogen (N) and phosphorus (P) removal of corn to determine the effects of these management strategies on crop and soil. In the runoff study, N and P-based beef cattle manure or compost were applied to no-till and disked s...

  5. REDUCTION OF HIGH SOIL TEST PHOSPHORUS BY CROP REMOVAL

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Soils with high phosphorus (P) level can contribute to excess P in runoff and the subsequent pollution of surface water. Excess P in the soil can be removed from the system by harvesting crops. The objectives of this study were to evaluate crop P removal effects on soil P reduction and to evaluate v...

  6. Mechanical and Electrical Anisotropy of Few-Layer Black Phosphorus.

    PubMed

    Tao, Jin; Shen, Wanfu; Wu, Sen; Liu, Lu; Feng, Zhihong; Wang, Chao; Hu, Chunguang; Yao, Pei; Zhang, Hao; Pang, Wei; Duan, Xuexin; Liu, Jing; Zhou, Chongwu; Zhang, Daihua

    2015-11-24

    We combined reflection difference microscopy, electron transport measurements, and atomic force microscopy to characterize the mechanical and electrical anisotropy of few-layer black phosphorus. We were able to identify the lattice orientations of the two-dimensional material and construct suspended structures aligned with specific crystal axes. The approach allowed us to probe the anisotropic mechanical and electrical properties along each lattice axis in separate measurements. We measured the Young's modulus of few-layer black phosphorus to be 58.6 ± 11.7 and 27.2 ± 4.1 GPa in zigzag and armchair directions. The breaking stress scaled almost linearly with the Young's modulus and was measured to be 4.79 ± 1.43 and 2.31 ± 0.71 GPa in the two directions. We have also observed highly anisotropic transport behavior in black phosphorus and derived the conductance anisotropy to be 63.7%. The test results agreed well with theoretical predictions. Our work provided very valuable experimental data and suggested an effective characterization means for future studies on black phosphorus and anisotropic two-dimensional nanomaterials in general. PMID:26422521

  7. Isolation and characterization of few-layer black phosphorus

    NASA Astrophysics Data System (ADS)

    Castellanos-Gomez, Andres; Vicarelli, Leonardo; Prada, Elsa; Island, Joshua O.; Narasimha-Acharya, K. L.; Blanter, Sofya I.; Groenendijk, Dirk J.; Buscema, Michele; Steele, Gary A.; Alvarez, J. V.; Zandbergen, Henny W.; Palacios, J. J.; van der Zant, Herre S. J.

    2014-09-01

    Isolation and characterization of mechanically exfoliated black phosphorus flakes with a thickness down to two single-layers is presented. A modification of the mechanical exfoliation method, which provides higher yield of atomically thin flakes than conventional mechanical exfoliation, has been developed. We present general guidelines to determine the number of layers using optical microscopy, Raman spectroscopy and transmission electron microscopy (TEM) in a fast and reliable way. Moreover, we demonstrate that the exfoliated flakes are highly crystalline and that they are stable even in free-standing form through Raman spectroscopy and TEM measurements. A strong thickness dependence of the band structure is found by density functional theory (DFT) calculations. The exciton binding energy, within an effective mass approximation, is also calculated for different number of layers. Our computational results for the optical gap are consistent with preliminary photoluminescence results on thin flakes. Finally, we study the environmental stability of black phosphorus flakes finding that the flakes are very hydrophilic and that long term exposure to air moisture etches black phosphorus away. Nonetheless, we demonstrate that the aging of the flakes is slow enough to allow fabrication of field-effect transistors with strong ambipolar behavior. DFT calculations also give us insight into the water-induced changes of the structural and electronic properties of black phosphorus.

  8. Development and testing of a new phosphorus index for Kentucky

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The phosphorus index (PI) is a field-scale assessment tool developed by the USDA Natural Resources Conservation Service (NRCS) to identify fields most vulnerable to P loss that has been adopted in some form across 48 states. Due to concerns that the use of the PI has not resulted in intended reduct...

  9. Methods to evaluate and update current phosphorus indices

    Technology Transfer Automated Retrieval System (TEKTRAN)

    In most states, the phosphorus (P) index (PI) is the adopted strategy for assessing a field’s vulnerability to P loss when preparing comprehensive nutrient management plans. Most state PIs, however, have not been rigorously evaluated against measured P loss data to determine how well the PI assigns ...

  10. Managing for Phosphorus and Other Resources in Globalized Agriculture

    NASA Astrophysics Data System (ADS)

    MacDonald, G. K.; Mueller, N. D.; Bennett, E.; Brauman, K. A.; Gerber, J. S.; Metson, G. S.; West, P. C.

    2014-12-01

    Agricultural trade has an important effect on the distribution of resource use among regions. Trade is particularly important for understanding human impacts on the phosphorus (P) cycle, as mineral P reserves are geopolitically concentrated. Yet, P use is only one component of the broader agro-environmental dimensions of globalized agriculture. Understanding complex interactions among multiple components of land use and resource management in trade networks is needed. We fuse comprehensive global agricultural datasets illustrating key facets of land use and management with bilateral trade statistics to explore phosphorus-use efficiency in relation to other agro-environmental indicators. Our findings illustrate tradeoffs among phosphorus-use efficiency, nitrogen-use efficiency, crop-water productivity, and overall crop yields embodied within trade networks. Disparities in the land-use intensity of different exporting countries reflect the types of commodities produced, the degree of export-orientation, and the biophysical context of production. Phosphorus inefficiencies could compound other problems, such as water scarcity, but our findings also reveal places with relatively high efficiency across multiple indicators—offering insight on how overall resource management can be balanced for export production. Using the prevailing agricultural systems of key exporting regions as a backdrop, we highlight opportunities to leverage agricultural efficiencies embodied in global trade networks to conserve multiple resources.

  11. Biochar effects on phosphorus pools in three soils from Minnesota

    Technology Transfer Automated Retrieval System (TEKTRAN)

    This greenhouse study was set up to assess the changes in the soil phosphorus (P) pools of three soils used for agricultural production in Minnesota as a result of biochar application and crop nutrient uptake. The soils included: excessively well-drained Hubbard loamy sand; poorly drained, calcareou...

  12. Phosphorus fate, management and modeling in artificially drained systems

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Phosphorus (P) losses in agricultural drainage waters, both surface and subsurface, are much more common than once recognized and are among the most difficult form of non-point source pollution to mitigate. Major advances have been made in understanding the mechanisms of P transport and in testing a...

  13. REDUCING MANURE PHOSPHORUS SOLUBILITY WITH ALUM AND COAL COMBUSTION BYPRODUCTS

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Animal manures contain large amounts of soluble phosphorus (P). This P is prone to runoff losses when manure is surface applied, contributing to water quality decline and eutrophication of streams and rivers. Here we report the efficacy of alum and three coal combustion byproducts in reducing P so...

  14. Conjugate and method for forming aminomethyl phosphorus conjugates

    DOEpatents

    Katti, Kattesh V. (Columbia, MO); Berning, Douglas E. (Columbia, MO); Volkert, Wynn A. (Columbia, MO); Ketring, Alan R. (Columbia, MO); Churchill, Robert (Columbia, MO)

    1999-01-01

    A method of forming phosphine-amine conjugates includes reacting a hydroxymethyl phosphine group of an amine-free first molecule with at least one free amine group of a second molecule to covalently bond the first molecule with the second molecule through an aminomethyl phosphorus linkage and the conjugates formed thereby.

  15. NUTRIENT DIVERSION: RESULTING LAKE TROPHIC STATE AND PHOSPHORUS DYNAMICS

    EPA Science Inventory

    Lake Sammamish, Washington, was studied during 1970-75 to determine its response to wastewater diversion in 1968. The results were compared with a pre-diversion study in 1964-65. Diversion reduced the phosphorus loading by about one-third (from 1.02 to 0.67 g P/sq m. yr and about...

  16. Phosphorus Losses from Agricultural Watersheds in the Mississippi Delta

    EPA Science Inventory

    High phosphorus (P) loss from agricultural fields has been an environmental concern because of potential water quality problems in streams and lakes. To better understand the process of P loss, rainfall, surface runoff, sediment, ortho-P and total P (TP) were measured (1996 to 2...

  17. Seed Phosphorus and the development of low-phytate crops

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Phytic acid (myo-inositol-1,2,3,4,5,6-hexakisphosphate or InsP6) represents 60% to 80% of mature seed total phosphorus (P), and is important to the nutritional quality of seeds when used in foods and feeds. Studies of the biochemistry of seed phytic acid synthesis indicates a complex, multibranched...

  18. Reducing Erosion and Phosphorus Movement in Potato Systems

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Soil erosion and phosphorus (P) runoff can be severe in potato production systems in the Northeast U.S., which are characterized by intensive tillage, minimal ground cover, low crop residue return, and steep slopes. We used rainfall simulators in the greenhouse and field to assess sediment and P mov...

  19. Phosphorus transport in agricultural subsurface drainage: A review

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Phosphorus (P) loss from agricultural fields and watersheds has been an important water quality issue for decades because of the critical role P plays in eutrophication. Historically, most research focused on P losses by surface runoff and erosion because subsurface P losses were often deemed to be ...

  20. Managing agricultural phosphorus for water quality protection: principles for progress

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The eutrophication of aquatic systems due to diffuse pollution of agricultural phosphorus (P) is a local, even regional, water quality problem that can be found world-wide. Sustainable management of P requires prudent tempering of agronomic practices, recognizing that additional steps are often requ...

  1. FGD gypsum filters remove soluble phosphorus from agricultural drainage waters

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Decades of chicken litter applications has led to phosphorus (P) levels up to ten times the agronomic optimum in soils of the Delmarva Peninsula. This legacy P is a major source of P entering drainage ditches that eventually empty into the Chesapeake Bay. A Flue Gas Desulfurization (FGD) gypsum ditc...

  2. Influence of phosphorus on the creep ductility of copper

    NASA Astrophysics Data System (ADS)

    Sandström, Rolf; Wu, Rui

    2013-10-01

    Around 1990 it was discovered that pure copper could have extra low creep ductility in the temperature interval 180-250 °C. The material was intended for use in canisters for nuclear waste disposal. Although extra low creep ductility was not observed much below 180 °C and the temperature in the canister will never exceed 100 °C, it was feared that the creep ductility could reach low values at lower temperatures after long term exposure. If 50 ppm phosphorus was added to the copper the low creep ductility disappeared. A creep cavitation model is presented that can quantitatively describe the cavitation behaviour in uniaxial and multiaxial creep tests as well as the observed creep ductility for copper with and without phosphorus. A so-called double ledge model has been introduced that demonstrates why the nucleation rate of creep cavities is often proportional to the creep rate. The phosphorus agglomerates at the grain boundaries and limits their local deformation and thereby reduces the formation and growth of cavities. This explains why extra low creep ductility does not occur in phosphorus alloyed copper.

  3. Patterns of sediment and phosphorus accumulation in a riparian buffer

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Riparian buffers prevent sediment and phosphorus (P) from reaching streams, but their accumulation in buffers is seldom measured. This study's objectives were to determine accumulations of sediment and P in a multi-species riparian buffer, and characterize spatial-temporal patterns of P in soil wate...

  4. GRAZING MANAGEMENT EFFECTS ON SEDIMENT AND PHOSPHORUS IN SURFACE RUNOFF

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Sediment and phosphorus (P) in runoff from pastures are potential non-point source pollutants in surface waters that may be influenced by surface cover, sward height, treading damage, surface slope, soil moisture, and soil P. The objectives of the current study were to evaluate their relationships w...

  5. Plant Growth and Phosphorus Uptake of Three Riparian Grass Species

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Riparian buffers can significantly reduce sediment-bound phosphorus (P) entering surface water, but control of dissolved P inputs is more challenging. Because plant roots remove P from soil solution, it follows that plant uptake will reduce dissolved P losses. We evaluated P uptake of smooth bromegr...

  6. Colossal Ultraviolet Photoresponsivity of Few-Layer Black Phosphorus.

    PubMed

    Wu, Jing; Koon, Gavin Kok Wai; Xiang, Du; Han, Cheng; Toh, Chee Tat; Kulkarni, Eeshan S; Verzhbitskiy, Ivan; Carvalho, Alexandra; Rodin, Aleksandr S; Koenig, Steven P; Eda, Goki; Chen, Wei; Neto, A H Castro; Özyilmaz, Barbaros

    2015-08-25

    Black phosphorus has an orthorhombic layered structure with a layer-dependent direct band gap from monolayer to bulk, making this material an emerging material for photodetection. Inspired by this and the recent excitement over this material, we studied the optoelectronics characteristics of high-quality, few-layer black phosphorus-based photodetectors over a wide spectrum ranging from near-ultraviolet (UV) to near-infrared (NIR). It is demonstrated for the first time that black phosphorus can be configured as an excellent UV photodetector with a specific detectivity ?3 × 10(13) Jones. More critically, we found that the UV photoresponsivity can be significantly enhanced to ?9 × 10(4) A W(-1) by applying a source-drain bias (VSD) of 3 V, which is the highest ever measured in any 2D material and 10(7) times higher than the previously reported value for black phosphorus. We attribute such a colossal UV photoresponsivity to the resonant-interband transition between two specially nested valence and conduction bands. These nested bands provide an unusually high density of states for highly efficient UV absorption due to the singularity of their nature. PMID:26207324

  7. Significant contribution of combustion-related emissions to the atmospheric phosphorus budget

    NASA Astrophysics Data System (ADS)

    Wang, Rong; Balkanski, Yves; Boucher, Olivier; Ciais, Philippe; Peñuelas, Josep; Tao, Shu

    2015-01-01

    Atmospheric phosphorus fertilizes plants and contributes to Earth's biogeochemical phosphorus cycle. However, calculations of the global budget of atmospheric phosphorus have been unbalanced, with global deposition exceeding estimated emissions from dust and sea-salt transport, volcanic eruptions, biogenic sources and combustion of fossil fuels, biofuels and biomass, the latter of which thought to contribute about 5% of total emissions. Here we use measurements of the phosphorus content of various fuels and estimates of the partitioning of phosphorus during combustion to calculate phosphorus emissions to the atmosphere from all combustion sources. We estimate combustion-related emissions of 1.8 Tg P yr-1, which represent over 50% of global atmospheric sources of phosphorus. Using these estimates in atmospheric transport model simulations, we find that the total global emissions of atmospheric phosphorus (3.5 Tg P yr-1) translate to a depositional sink of 2.7 Tg P yr-1 over land and 0.8 Tg P yr-1 over the oceans. The modelled spatial patterns of phosphorus deposition agree with observations from globally distributed measurement stations, and indicate a near balance of the phosphorus budget. Our finding suggests that the perturbation of the global phosphorus cycle by anthropogenic emissions is larger thanpreviously thought.

  8. A Regional Modeling Framework of Phosphorus Sources and Transport in Streams of the Southeastern United States

    USGS Publications Warehouse

    Garcia, A.M.; Hoos, A.B.; Terziotti, S.

    2011-01-01

    We applied the SPARROW model to estimate phosphorus transport from catchments to stream reaches and subsequent delivery to major receiving water bodies in the Southeastern United States (U.S.). We show that six source variables and five land-to-water transport variables are significant (p<0.05) in explaining 67% of the variability in long-term log-transformed mean annual phosphorus yields. Three land-to-water variables are a subset of landscape characteristics that have been used as transport factors in phosphorus indices developed by state agencies and are identified through experimental research as influencing land-to-water phosphorus transport at field and plot scales. Two land-to-water variables - soil organic matter and soil pH - are associated with phosphorus sorption, a significant finding given that most state-developed phosphorus indices do not explicitly contain variables for sorption processes. Our findings for Southeastern U.S. streams emphasize the importance of accounting for phosphorus present in the soil profile to predict attainable instream water quality. Regional estimates of phosphorus associated with soil-parent rock were highly significant in explaining instream phosphorus yield variability. Model predictions associate 31% of phosphorus delivered to receiving water bodies to geology and the highest total phosphorus yields in the Southeast were catchments with already high background levels that have been impacted by human activity. ?? 2011 American Water Resources Association. This article is a US Government work and is in the public domain in the USA.

  9. Plasma-Assisted Synthesis of High-Mobility Atomically Layered Violet Phosphorus.

    PubMed

    Tsai, Hsu-Sheng; Lai, Chih-Chung; Hsiao, Ching-Hung; Medina, Henry; Su, Teng-Yu; Ouyang, Hao; Chen, Tai-Hsiang; Liang, Jenq-Horng; Chueh, Yu-Lun

    2015-07-01

    Two-dimensional layered materials such as graphene, transition metal dichalcogenides, and black phosphorus have demonstrated outstanding properties due to electron confinement as the thickness is reduced to atomic scale. Among the phosphorus allotropes, black phosphorus, and violet phosphorus possess layer structure with the potential to be scaled down to atomically thin film. For the first time, the plasma-assisted synthesis of atomically layered violet phosphorus has been achieved. Material characterization supports the formation of violet phosphorus/InN over InP substrate where the layer structure of violet phosphorus is clearly observed. The identification of the crystal structure and lattice constant ratifies the formation of violet phosphorus indeed. The critical concept of this synthesis method is the selective reaction induced by different variations of Gibbs free energy (?G) of reactions. Besides, the Hall mobility of the violet phosphorus on the InP substrate greatly increases over the theoretical values of InP bulk material without much reduction in the carrier concentration, suggesting that the mobility enhancement results from the violet phosphorus layers. Furthermore, this study demonstrates a low-cost technique with high compatibility to synthesize the high-mobility atomically layered violet phosphorus and open the space for the study of the fundamental properties of this intriguing material as a new member of the fast growing family of 2D crystals. PMID:26070035

  10. Translocation of Carbon-14 in Sugarcane Plants Supplied with or Deprived of Phosphorus 1

    PubMed Central

    Hartt, Constance E.

    1972-01-01

    Translocation of radioactive carbon from the fed part of a blade to the rest of the plant was impaired by a deficiency in phosphorus only when the level of phosphorus was low enough to decrease growth. Phosphorus deficiency decreased the percentage of inorganic phosphorus more than that of organic phosphorus, indicating little effect of phosphorus deficiency upon phosphorylation. Thus phosphorus deficiency did not reduce phosphorylation enough to affect translocation. Evidence for the involvement of phosphorylation in translocation obtained from studies with potassium deficiency, light intensity and quality, 3-(p-chlorophenyl)-1, 1-dimethylurea and 3-(3,4-dichlorophenyl)-1, 1-dimethylurea, and carbon dioxide suggests that noncyclic photosynthetic phosphorylation provides the energy for phototranslocation. PMID:16658003

  11. Effect of phosphorus on biodiesel production from Scenedesmus obliquus under nitrogen-deficiency stress.

    PubMed

    Chu, Fei-Fei; Chu, Pei-Na; Shen, Xiao-Fei; Lam, Paul K S; Zeng, Raymond J

    2014-01-01

    In order to study the effect of phosphorus on biodiesel production from Scenedesmus obliquus especially under nitrogen deficiency conditions, six types of media with combinations of nitrogen repletion/depletion and phosphorus repletion/limitation/depletion were investigated in this study. It was found that nitrogen starvation compared to nitrogen repletion enhanced biodiesel productivity. Moreover, biodiesel productivity was further strengthened by varying the supply level of phosphorus from depletion, limitation, through to repletion. The maximum FAMEs productivity of 24.2 mg/L/day was obtained in nitrogen depletion with phosphorus repletion, which was two times higher than that in nutrient complete medium. More phosphorus was accumulated in cells under the nitrogen starvation with sufficient phosphorus condition, but no polyphosphate was formed. This study indicated that nitrogen starvation plus sufficient P supply might be the real "lipid trigger". Furthermore, results of the current study suggest a potential application for utilizing microalgae to combine phosphorus removal from wastewater with biodiesel production. PMID:24292204

  12. Phosphorus and the Kidney: What Is Known and What Is Needed12

    PubMed Central

    Nadkarni, Girish N.; Uribarri, Jaime

    2014-01-01

    A major role of the kidneys is to maintain phosphorus homeostasis. High serum phosphorus has been linked to all-cause and cardiovascular mortality in chronic kidney disease (CKD) both before and after initiation of renal replacement therapy. Considering the clinical implications of uncontrolled hyperphosphatemia, maintenance of phosphorus concentrations within an optimum range is standard of care in this patient population. Recently, the epidemiologic associations between serum phosphorus and worse outcome have been extended to the general population. This becomes even more important in view of the increasing dietary phosphorus intake in the American diet due in large part to the greater consumption of foods processed with phosphate additives. A greater understanding of mechanisms and epidemiology of altered phosphorus metabolism and disease in CKD may help clarify the possible role of excess dietary phosphorus as a health risk factor in the general population. PMID:24425728

  13. Load estimation and source apportionment of nonpoint source nitrogen and phosphorus based on integrated application of SLURP model, ECM, and RUSLE: a case study in the Jinjiang River, China.

    PubMed

    Chen, Haiyang; Teng, Yanguo; Wang, Jinsheng

    2013-02-01

    The nonpoint source (NPS) pollution is difficult to manage and control due to its complicated generation and formation. Load estimation and source apportionment are an important and necessary process for efficient NPS control. Here, an integrated application of semi-distributed land use-based runoff process (SLURP) model, export coefficients model (ECM), and revise universal soil loss equation (RUSLE) for the load estimation and source apportionment of nitrogen and phosphorus was proposed. The Jinjiang River (China) was chosen for the evaluation of the method proposed here. The chosen watershed was divided into 27 subbasins. After which, the SLURP model was used to calculate land use runoff and to estimate loads of dissolved nitrogen and phosphorus, and ECM was applied to estimate dissolved loads from livestock and rural domestic sewage. Next, the RUSLE was employed for load estimation of adsorbed nitrogen and phosphorus. The results showed that the 12,029.06 t a(-1) pollution loads of total NPS nitrogen (TN) mainly originated from dissolved nitrogen (96.24 %). The major sources of TN were land use runoff, which accounted for 45.97 % of the total, followed by livestock (32.43 %) and rural domestic sewage (17.83 %). For total NPS phosphorous (TP), its pollution loads were 570.82 t a(-1) and made up of dissolved and adsorbed phosphorous with 66.29 and 33.71 % respectively. Soil erosion, land use runoff, rural domestic sewage, and livestock were the main sources of phosphorus with contribution ratios of 33.71, 45.73, 14.32, and 6.24 % respectively. Therefore, land use runoff, livestock, and soil erosion were identified as the main pollution sources to influence loads of NPS nitrogen and phosphorus in the Jinjiang River and should be controlled first. The method developed here provided a helpful guideline for conducting NPS pollution management in similar watershed. PMID:22644124

  14. Immobilization of non-point phosphorus using stabilized magnetite nanoparticles with enhanced transportability and reactivity in soils.

    PubMed

    Pan, Gang; Li, Lei; Zhao, Dongye; Chen, Hao

    2010-01-01

    Laboratory batch and column experiments were conducted to investigate the immobilization of phosphorus (P) in soils using synthetic magnetite nanoparticles stabilized with sodium carboxymethyl cellulose (CMC-NP). Although CMC-stabilized magnetite particles were at the nanoscale, phosphorus removal by the nanoparticles was less than that of microparticles (MP) without the stabilizer due to the reduced P reactivity caused by the coating. The P reactivity of CMC-NP was effectively recovered when cellulase was added to degrade the coating. For subsurface non-point P pollution control for a water pond, it is possible to inject CMC-NP to form an enclosed protection wall in the surrounding soils. Non-stabilized "nanomagnetite" could not pass through the soil column under gravity because it quickly agglomerated into microparticles. The immobilized P was 30% in the control soil column, 33% when treated by non-stabilized MP, 45% when treated by CMC-NP, and 73% when treated by both CMC-NP and cellulase. PMID:19732999

  15. PSYCHIC A process-based model of phosphorus and sediment transfers within agricultural catchments. Part 2. A preliminary evaluation

    NASA Astrophysics Data System (ADS)

    Strömqvist, J.; Collins, A. L.; Davison, P. S.; Lord, E. I.

    2008-02-01

    SummaryThis paper describes the preliminary evaluation of the PSYCHIC catchment scale (Tier 1) model for predicting the mobilisation and delivery of phosphorus (P) and suspended sediment (SS) in the Hampshire Avon (1715 km 2) and Herefordshire Wye (4017 km 2) drainage basins, in the UK, using empirical data. Phosphorus and SS transfers to watercourses in the Wye were predicted to be greater than corresponding delivery in the Avon; SS, 249 vs 33 kg ha -1 yr -1; DP, 2.57 vs 1.26 kg ha -1 yr -1; PP, 2.20 vs 0.56 kg ha -1 yr -1. The spatial pattern of the predicted transfers was relatively uniform across the Wye drainage basin, whilst in the Avon, delivery to watercourses was largely confined to the river corridors and small areas of drained land. Statistical performance in relation to predicted exports of P and SS, using criteria for relative error (RE) and root mean square error (RMSE), reflected the potential shortcomings associated with using longer-term climate data for predicting shorter-term (2002-2004) catchment response and the need to refine calculations of point source contributions and to incorporate additional river basin processes such as channel bank erosion and in-stream geochemical processing. PSYCHIC is therefore best suited to characterising longer-term catchment response.

  16. [Characteristics and bioavailability of organic phosphorus from different sources of sediments in Dianchi Lake].

    PubMed

    Xiong, Qiang; Jiao Li, Xing; Wang, Sheng-Rui; Peng, Xi-Long

    2014-11-01

    The content and vertical distribution characteristics of organic phosphorus were studied by collecting core sediments of Dianchi Lake, characterizing the bioavailability of different organic phosphorus species of these sediments by enzymatic hydrolysis. The results indicated that, (1) The inorganic phosphorus represented primary portions of extractable phosphorus of sediments in Dianchi Lake, except for the H2O extractable organic phosphorus (H2O-P(o)). The rank of order of organic phosphorus fractionation in sediments was NaOH extractable organic phosphorus (NaOH-P(o)) > NaHCO3 extractable organic phosphorus (NaHCO3-P(o)) > H2O-P(o) > HCl extractable organic phosphorus (HCl-P(o)). The vertical distribution of NaOH-P(o), NaHCO3-P(o) and H2O-P(o) with relatively high mobility showed the trend of topper layer > middle layer > bottom layer. (2) Labile monoester P predominated in enzymatically hydrolysable phosphorus (EHP) of sediments in Dianchi Lake. The EHP content of NaOH-P0, NaHCO3-Po and H20-P0 in sediments of Dianchi Lake were 0.11-5.93, 0-45.32 and 0-107.11 mg x kg(-1), respectively. The EHP content of different organic phosphorus species followed the order: NaOH-P(o) > NaHCO3-P(o) > H2O-P(o), with the trend of vertical distribution of topper layer > middle layer > bottom layer. The bioavailability of organic phosphorus of different depth showed the order of topper layer > middle layer > bottom layer. (3) EHP was a considerable source of the bioavailable phosphorus of sediments in Dianchi Lake. The protection of water quality in Dianchi Lake should consider the effects of EHP in sediments. When the external phosphorus load was restricted gradually, the biogeochemical cycle of EHP in sediments might play an important role in maintaining the eutrophication of Dianchi Lake. PMID:25639084

  17. Distribution and estimated release of sediment phosphorus in the northern Baltic Sea archipelagos

    NASA Astrophysics Data System (ADS)

    Puttonen, Irma; Mattila, Johanna; Jonsson, Per; Karlsson, O. Magnus; Kohonen, Tuula; Kotilainen, Aarno; Lukkari, Kaarina; Malmaeus, J. Mikael; Rydin, Emil

    2014-05-01

    Phosphorus contents in the sediments were determined in archipelago areas of the northern Baltic Sea (Svealand in Sweden and Åland, SW Finland and W Uusimaa in Finland) during 2008-2012. Spatial and vertical distribution of phosphorus was studied by analysing sediment samples from 345 stations of different seabed substrate types. A sequential extraction method was applied to evaluate the pool of the potentially mobile phosphorus, i.e., the amount of phosphorus that can be expected to be released from sediments to water with time, and possibly support primary production. In addition, vertical distribution of immobile phosphorus forms in the sediments was used as a tool to assess phosphorus burial. The uppermost 2 cm of sediments were calculated to contain 126,000 tonnes of phosphorus in the study area covering 19,200 km2 of the seafloor. Subtracting the assumed average background content (i.e. that assumed to be buried) of this total phosphorus content gave an estimation of 31,000-37,000 tonnes of potentially mobile phosphorus at the sediment surface. Redox sensitive iron-bound phosphorus accounts for two thirds of this pool. Compared with the total phosphorus input from the catchment of the entire Baltic Sea - 29,000 tonnes in 2009 - it can be concluded that the store of phosphorus that can be released with time from the sediments is large, and that internal phosphorus recycling processes thus may play a key role in phosphorus fluxes in the coastal zone. Spreading of hypoxia in the future, as recent modelling and sediment proxy results suggest, is likely to severely deteriorate the water quality, particularly in the archipelago areas where the water exchange is slow.

  18. 30 CFR 33.33 - Allowable limits of dust concentration.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 30 Mineral Resources 1 2014-07-01 2014-07-01 false Allowable limits of dust concentration. 33.33 Section 33.33 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR TESTING, EVALUATION, AND APPROVAL OF MINING PRODUCTS DUST COLLECTORS FOR USE IN CONNECTION WITH ROCK DRILLING IN...

  19. 30 CFR 33.33 - Allowable limits of dust concentration.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 30 Mineral Resources 1 2013-07-01 2013-07-01 false Allowable limits of dust concentration. 33.33 Section 33.33 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR TESTING, EVALUATION, AND APPROVAL OF MINING PRODUCTS DUST COLLECTORS FOR USE IN CONNECTION WITH ROCK DRILLING IN...

  20. 30 CFR 33.33 - Allowable limits of dust concentration.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 30 Mineral Resources 1 2011-07-01 2011-07-01 false Allowable limits of dust concentration. 33.33 Section 33.33 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR TESTING, EVALUATION, AND APPROVAL OF MINING PRODUCTS DUST COLLECTORS FOR USE IN CONNECTION WITH ROCK DRILLING IN...

  1. 30 CFR 33.33 - Allowable limits of dust concentration.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Allowable limits of dust concentration. 33.33 Section 33.33 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR TESTING, EVALUATION, AND APPROVAL OF MINING PRODUCTS DUST COLLECTORS FOR USE IN CONNECTION WITH ROCK DRILLING IN...

  2. 30 CFR 33.33 - Allowable limits of dust concentration.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 30 Mineral Resources 1 2012-07-01 2012-07-01 false Allowable limits of dust concentration. 33.33 Section 33.33 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR TESTING, EVALUATION, AND APPROVAL OF MINING PRODUCTS DUST COLLECTORS FOR USE IN CONNECTION WITH ROCK DRILLING IN...

  3. Tillage System Effect on Vertical Phosphorus Stratification and Phosphorus Uptake of Winter Wheat, Winter Pea, and Spring Pea

    E-print Network

    Lawrence, Rick L.

    with hoe-type openers at 12 in. row spacing. Phosphorus fertilizer (0-45-0) was applied at 22.5 lb P2O5/ac al. 2006; Selles et al. 1999). Consequently, P availability, and hence, P fertilizer needs, may uptake, and hence P availability and fertilizer need, is different between tillage systems. Methods

  4. Impact of nitrite on aerobic phosphorus uptake by poly-phosphate accumulating organisms in enhanced biological phosphorus removal sludges.

    PubMed

    Zeng, Wei; Li, Boxiao; Yang, Yingying; Wang, Xiangdong; Li, Lei; Peng, Yongzhen

    2014-02-01

    Impact of nitrite on aerobic phosphorus (P) uptake of poly-phosphate accumulating organisms (PAOs) in three different enhanced biological phosphorus removal (EBPR) systems was investigated, i.e., the enriched PAOs culture fed with synthetic wastewater, the two lab-scale sequencing batch reactors (SBRs) treating domestic wastewater for nutrient removal through nitrite-pathway nitritation and nitrate-pathway nitrification, respectively. Fluorescence in situ hybridization results showed that PAOs in the three sludges accounted for 72, 7.6 and 6.5% of bacteria, respectively. In the enriched PAOs culture, at free nitrous acid (FNA) concentration of 0.47 × 10(-3) mg HNO?-N/L, aerobic P-uptake and oxidation of intercellular poly-?-hydroxyalkanoates were both inhibited. Denitrifying phosphorus removal under the aerobic conditions was observed, indicating the existence of PAOs using nitrite as electron acceptor in this culture. When the FNA concentration reached 2.25 × 10(-3) mg HNO2-N/L, denitrifying phosphorus removal was also inhibited. And the inhibition ceased once nitrite was exhausted. Corresponding to both SBRs treating domestic wastewater with nitritation and nitrification pathway, nitrite inhibition on aerobic P-uptake by PAOs did not occur even though FNA concentration reached 3 × 10(-3) and 2.13 × 10(-3) mg HNO?-N/L, respectively. Therefore, PAOs taken from different EBPR activated sludges had different tolerance to nitrite. PMID:23771179

  5. Simultaneous nitrogen and phosphorus removal in the sulfur cycle-associated Enhanced Biological Phosphorus Removal (EBPR) process.

    PubMed

    Wu, Di; Ekama, George A; Wang, Hai-Guang; Wei, Li; Lu, Hui; Chui, Ho-Kwong; Liu, Wen-Tso; Brdjanovic, Damir; van Loosdrecht, Mark C M; Chen, Guang-Hao

    2014-02-01

    Hong Kong has practiced seawater toilet flushing since 1958, saving 750,000 m(3) of freshwater every day. A high sulfate-to-COD ratio (>1.25 mg SO4(2-)/mg COD) in the saline sewage resulting from this practice has enabled us to develop the Sulfate reduction, Autotrophic denitrification and Nitrification Integrated (SANI(®)) process with minimal sludge production and oxygen demand. Recently, the SANI(®) process has been expanded to include Enhanced Biological Phosphorus Removal (EBPR) in an alternating anaerobic/limited-oxygen (LOS-EBPR) aerobic sequencing batch reactor (SBR). This paper presents further development - an anaerobic/anoxic denitrifying sulfur cycle-associated EBPR, named as DS-EBPR, bioprocess in an alternating anaerobic/anoxic SBR for simultaneous removal of organics, nitrogen and phosphorus. The 211 day SBR operation confirmed the sulfur cycle-associated biological phosphorus uptake utilizing nitrate as electron acceptor. This new bioprocess cannot only reduce operation time but also enhance volumetric loading of SBR compared with the LOS-EBPR. The DS-EBPR process performed well at high temperatures of 30 °C and a high salinity of 20% seawater. A synergistic relationship may exist between sulfur cycle and biological phosphorus removal as the optimal ratio of P-release to SO4(2-)-reduction is close to 1.0 mg P/mg S. There were no conventional PAOs in the sludge. PMID:24342048

  6. Using the annual phosphorus loss estimator (APLE) model to evaluate the University of Maryland phosphorus management tool

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Maryland’s phosphorus site index (PSI) has been used to guide management decisions to minimize the potential for P loss from agricultural fields in Maryland since the adoption of the Water Quality Improvement Act of 1998. The index was recently revised and renamed the University of Maryland Phospho...

  7. The Role of Organic Phosphorus in Alum ability to Reduce Phosphorus Solubility in Poultry Litter and Litter Amended Soils

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Alum (Al2[SO4]3) addition to litter in poultry houses is an effective strategy for reducing phosphorus (P) solubility in the litter and litter-amended soils, thereby reducing the potential for soluble P losses in runoff. Although there has been much research on the subject, there is still uncertaint...

  8. The involvement of expansins in responses to phosphorus availability in wheat, and its potentials in improving phosphorus efficiency of plants.

    PubMed

    Han, Yang-yang; Zhou, Shan; Chen, Yan-hui; Kong, Xiangzhu; Xu, Ying; Wang, Wei

    2014-05-01

    Phosphorus (P) is a critical macronutrient required for numerous functions in plants and is one of the limiting factors for plant growth. Phosphate availability has a strong effect on root system architecture. Expansins are encoded by a superfamily of genes that are organized into four families, and growing evidence has demonstrated that expansins are involved in almost all aspects of plant development, especially root development. In the current study, we demonstrate that expansins may be involved in increasing phosphorus availability by regulating the growth and development of plant roots. Multiple expansins (five ?- and nine ?-expansin genes) were up- or down-regulated in response to phosphorus and showed different expression patterns in wheat. Meanwhile, the expression level of TaEXPB23 was up-regulated at excess-P condition, suggesting the involvement of TaEXPB23 in phosphorus adaptability. Overexpression of the TaEXPB23 resulted in improved phenotypes, particularly improved root system architecture, as indicated by the increased number of lateral roots in transgenic tobacco plants under excess-P and low-P conditions. Thus, these transgenic plants maintained better photosynthetic gas exchange ability than the control under both P-sufficient and P-deficient conditions. PMID:24636907

  9. Legacy phosphorus in calcareous soils: effects of long-term poultry litter application on phosphorus distribution in Texas Blackland Vertisol

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Sequential fractionation techniques, coupled with phosphatase hydrolysis, have allowed for greater understanding of manure/litter effects on soil phosphorus (P) distribution. We evaluated the effect of long-term (> 10 years) poultry litter (broiler and turkey litter) application at rates of 4.5, 6.7...

  10. Phosphorus in Phoenix: a budget and spatial representation of phosphorus in an urban ecosystem.

    PubMed

    Metson, Geneviève S; Hale, Rebecca L; Iwaniec, David M; Cook, Elizabeth M; Corman, Jessica R; Galletti, Christopher S; Childers, Daniel L

    2012-03-01

    As urban environments dominate the landscape, we need to examine how limiting nutrients such as phosphorus (P) cycle in these novel ecosystems. Sustainable management of P resources is necessary to ensure global food security and to minimize freshwater pollution. We used a spatially explicit budget to quantify the pools and fluxes of P in the Greater Phoenix Area in Arizona, USA, using the boundaries of the Central Arizona-Phoenix Long-Term Ecological Research site. Inputs were dominated by direct imports of food and fertilizer for local agriculture, while most outputs were small, including water, crops, and material destined for recycling. Internally, fluxes were dominated by transfers of food and feed from local agriculture and the recycling of human and animal excretion. Spatial correction of P dynamics across the city showed that human density and associated infrastructure, especially asphalt, dominated the distribution of P pools across the landscape. Phosphorus fluxes were dominated by agricultural production, with agricultural soils accumulating P. Human features (infrastructure, technology, and waste management decisions) and biophysical characteristics (soil properties, water fluxes, and storage) mediated P dynamics in Phoenix. P cycling was most notably affected by water management practices that conserve and recycle water, preventing the loss of waterborne P from the ecosystem. P is not intentionally managed, and as a result, changes in land use and demographics, particularly increased urbanization and declining agriculture, may lead to increased losses of P from this system. We suggest that city managers should minimize cross-boundary fluxes of P to the city. Reduced P fluxes may be accomplished through more efficient recycling of waste, therefore decreasing dependence on external nonrenewable P resources and minimizing aquatic pollution. Our spatial approach and consideration of both pools and fluxes across a heterogeneous urban ecosystem increases the utility of nutrient budgets for city managers. Our budget explicitly links processes that affect P cycling across space with the management of other resources (e.g., water). A holistic management strategy that deliberately couples the management of P and other resources should be a priority for cities in achieving urban sustainability. PMID:22611866

  11. Coral Uptake of Inorganic Phosphorus and Nitrogen Negatively Affected by Simultaneous Changes in Temperature and pH

    PubMed Central

    Godinot, Claire; Houlbrèque, Fanny

    2011-01-01

    The effects of ocean acidification and elevated seawater temperature on coral calcification and photosynthesis have been extensively investigated over the last two decades, whereas they are still unknown on nutrient uptake, despite their importance for coral energetics. We therefore studied the separate and combined impacts of increases in temperature and pCO2 on phosphate, ammonium, and nitrate uptake rates by the scleractinian coral S. pistillata. Three experiments were performed, during 10 days i) at three pHT conditions (8.1, 7.8, and 7.5) and normal temperature (26°C), ii) at three temperature conditions (26°, 29°C, and 33°C) and normal pHT (8.1), and iii) at three pHT conditions (8.1, 7.8, and 7.5) and elevated temperature (33°C). After 10 days of incubation, corals had not bleached, as protein, chlorophyll, and zooxanthellae contents were the same in all treatments. However, photosynthetic rates significantly decreased at 33°C, and were further reduced for the pHT 7.5. The photosynthetic efficiency of PSII was only decreased by elevated temperature. Nutrient uptake rates were not affected by a change in pH alone. Conversely, elevated temperature (33°C) alone induced an increase in phosphate uptake but a severe decrease in nitrate and ammonium uptake rates, even leading to a release of nitrogen into seawater. Combination of high temperature (33°C) and low pHT (7.5) resulted in a significant decrease in phosphate and nitrate uptake rates compared to control corals (26°C, pHT?=?8.1). These results indicate that both inorganic nitrogen and phosphorus metabolism may be negatively affected by the cumulative effects of ocean warming and acidification. PMID:21949839

  12. X-33 Development History

    NASA Technical Reports Server (NTRS)

    Butrica, Andrew J.

    1997-01-01

    The problem of dealing with various types of proprietary documents, whether from the Lockheed Martin, the Skunk Works, McDonnell Douglas, Rockwell, and other corporations extant or extinct, remains unresolved. The computerized archive finding aid has over 100 records at present. These records consist of X-33 photographs, press releases, media clippings, and the small number of X-33 project records collected to date.

  13. Separation of P Phase and Fe Phase in High Phosphorus Oolitic Iron Ore by Ultrafine Grinding and Gaseous Reduction in a Rotary Furnace

    NASA Astrophysics Data System (ADS)

    Gao, Jintao; Guo, Lei; Guo, Zhancheng

    2015-10-01

    Due to the oolitic structure of the high phosphorus iron ore and the closely wrapping of apatite and hematite phases, an approach using jet mill was utilized to grind the ore to ultrafine 0.01 to 0.001 mm, which realizes the dissociation of apatite phase and hematite phase. Then in a laboratory scale rotary furnace, high phosphorus ores of different sizes were reduced by reducing gas at sub-melting point temperatures (973 to 1173 K [700 to 900 °C]). In the rotating inclined reactor, the ore particles reacted with the reducing gas coming from the opposite direction in a rolling and discrete state, which greatly improved the kinetic conditions. In this study, the reaction rate increases significantly with the decrease of particle size. For the ultrafine high phosphorus iron ores, the metallization ratio can reach 83.91 to 97.32 pct, but only 33.24 to 40.22 pct for powders with the size of 0.13 to 0.15 mm. The reduced particles maintained their original sizes, without the presence of sintering phenomenon or iron whisker. Hence, two kinds of products were easily obtained by magnetic separation: the iron product with 91.42 wt pct of Fe and 0.19 wt pct of P, and the gangue product with 13.77 wt pct of Fe and 2.32 wt pct of P.

  14. Rethinking soil erosion, phosphorus and colloid transfers from intensive grasslands

    NASA Astrophysics Data System (ADS)

    Brazier, R. E.; Bilotta, G.

    2006-12-01

    The general consensus from the relatively small amount of existing research into soil erosion and nutrient export from intensive grasslands suggests that they are not a significant source of either sediment or phosphorus (P) (Bilotta et al., 2006). Authors have often attributed the low rates of erosion on intensive grasslands to the effect of the high surface cover which acts to intercept raindrops and retard runoff, resulting in limited detachment and transport of soil particles and so low sediment and particulate-phosphorus losses from these environments. Consequently, researchers have proposed that the phosphorus transfer from intensive grasslands is dominated by soluble forms of phosphorus, arbitrarily defined as anything that passes through a 0.45 ?m filter (Sharpley et al., 2000). Nevertheless, researchers studying surface water quality issues in areas that are dominated by intensive grasslands are finding problems associated with the delivery of sediment and sediment-bound contaminants (Heathwaite and Dils, 2000). Clearly there are some inconsistencies within the literature which need to be re-examined. Work presented here aims to question why these inconsistencies exist and presents results from a field experiment designed to further understanding of the response of grasslands in terms of sediment and phosphorus delivery from intensively managed grasslands. The field-based experiment comprises paired lysimeter studies, run as part of the Rowden Experimental Research Platform (RERP) at the Institute of Grassland and Environmental Research, Devon, UK. Six one-hectare Lysimeters are used to observe response to natural rainfall events in terms of overland flow, subsurface (or drained) flow, sediment flux, Total Phosphorus (TP) flux, conductivity, temperature and turbidity. Plots are equipped to monitor surface flow and drained flow in isolation, so that the effect of land drainage, common to intensively grazed land on heavy soils, can be assessed alongside undrained plots. Results are presented as time series at each plot as well as event, monthly, seasonal and annual budgets. Results indicate that significant, event-based yields of both sediments (1.18 kg ha-1 from drained plots and 3.09 kg ha-1 from undrained plots) and nutrients (3.9 g ha-1 of TP from drained plots and 9.86 g ha-1 from undrained plots) are forthcoming, as the artificial drainage influences both the hydrograph response and form to natural rainfall events. In addition, significant yields of fine particles (<0.45ìm), of both organic and inorganic origin (colloids) are observed, from both drained and undrained plots, associated with high levels of particulate phosphorus. Such results suggest that though grasslands may not suffer from `classical' erosion processes, such as rilling and gullying, they can still contribute significant levels of fine sediments and nutrients, whether they are drained or not, which in turn will make a detrimental impact on the quality of adjacent surface waters. Bilotta, G. S., and Brazier, R.E. (in press). Rethinking soil erosion and sediment and colloid transfers from intensive grasslands. Hydrological Processes. Heathwaite, A.L. and Dils, R.M. (2000) Characterising phosphorus loss in surface and subsurface hydrological pathways. The Science Of The Total Environment, 251/252: 523-538. Sharpley, A.N., Foy, R.H. and Withers, P.J.A. (2000) Practical and innovative measures for the control of agricultural phosphorus losses to water. An Overview. Journal of Environmental Quality, 29: 1-9.

  15. Screening of Phosphorus-Accumulating Fungi and Their Potential for Phosphorus Removal from Waste Streams.

    PubMed

    Ye, Yulin; Gan, Jing; Hu, Bo

    2015-11-01

    While bacteria have been primarily studied for phosphorus (P) removal in wastewater treatment, fungi and their ability to accumulate intracellular polyphosphate are less investigated. P-accumulating fungal strains were screened from soybean plants and surrounding soil by flask cultivation with potato dextrose broth and KH2PO4 in this study. Mucor circinelloides was selected for its high efficiency in P removal efficiency and high cellular P content. Neisser staining and growth-curve analysis confirmed that M. circinelloides stored polyphosphate intracellularly by luxury phosphate uptake. The effect of culture medium compositions on P removal efficiency and cellular P content was also investigated. Monosaccharides (such as glucose and fructose) and organic nitrogen (N, such as urea, and peptone) promoted fungi growth and P accumulation. M. circinelloides also preferred organic phosphates. When glucose, urea, and phytic acid sodium salt were used as the carbon, N, and P source, respectively, the maximum utilization efficiency was 40.1 % for P and 7.08 % for cellular P content. In addition, the potential of M. circinelloides for P removal from waste streams was investigated. Compared with the non-inoculated control culture, inoculation with M. circinelloides improved the soluble P removal in treating wastewater centrate, screened manure, and digested manure. PMID:26280802

  16. Complex Forms of Soil Organic Phosphorus-A Major Component of Soil Phosphorus.

    PubMed

    McLaren, Timothy I; Smernik, Ronald J; McLaughlin, Mike J; McBeath, Therese M; Kirby, Jason K; Simpson, Richard J; Guppy, Christopher N; Doolette, Ashlea L; Richardson, Alan E

    2015-11-17

    Phosphorus (P) is an essential element for life, an innate constituent of soil organic matter, and a major anthropogenic input to terrestrial ecosystems. The supply of P to living organisms is strongly dependent on the dynamics of soil organic P. However, fluxes of P through soil organic matter remain unclear because only a minority (typically <30%) of soil organic P has been identified as recognizable biomolecules of low molecular weight (e.g., inositol hexakisphosphates). Here, we use (31)P nuclear magnetic resonance spectroscopy to determine the speciation of organic P in soil extracts fractionated into two molecular weight ranges. Speciation of organic P in the high molecular weight fraction (>10 kDa) was markedly different to that of the low molecular weight fraction (<10 kDa). The former was dominated by a broad peak, which is consistent with P bound by phosphomonoester linkages of supra-/macro-molecular structures, whereas the latter contained all of the sharp peaks that were present in unfractionated extracts, along with some broad signal. Overall, phosphomonoesters in supra-/macro-molecular structures were found to account for the majority (61% to 73%) of soil organic P across the five diverse soils. These soil phosphomonoesters will need to be integrated within current models of the inorganic-organic P cycle of soil-plant terrestrial ecosystems. PMID:26492192

  17. Highly efficient uptake of phosphorus in epiphytic bromeliads

    PubMed Central

    Winkler, Uwe; Zotz, Gerhard

    2009-01-01

    Background and Aims Vascular epiphytes which can be abundant in tree crowns of tropical forests have to cope with low and highly intermittent water and nutrient supply from rainwater, throughfall and stem flow. Phosphorus rather than nitrogen has been suggested as the most limiting nutrient element, but, unlike nitrogen, this element has received little attention in physiological studies. This motivated the present report, in which phosphate uptake kinetics by leaves and roots, the subsequent distribution within plants and the metabolic fate of phosphate were studied as a step towards an improved understanding of physiological adaptations to the conditions of tree canopies. Methods Radioactively labelled [32P]phosphate was used to study uptake kinetics and plant distribution of phosphorus absorbed from bromeliad tanks. The metabolism of low molecular phosphorus metabolites was analysed by thin-layer chromatography followed by autoradiography. Key Results Uptake of phosphate from tanks is an ATP-dependent process. The kinetics of phosphorus uptake suggest that epiphytes possess effective phosphate transporters. The Km value of 1·05 µm determined for leaves of the bromeliad Aechmea fasciata is comparable with values obtained for the high affinity phosphate transporters in roots of terrestrial plants. In this species, young leaves are the main sink for phosphate absorbed from tank water. Within these leaves, phosphate is then allocated from the basal uptake zone into distal sections of the leaves. More than 80 % of the phosphate incorporated into leaves is not used in metabolism but stored as phytin. Conclusions Tank epiphytes are adapted to low and intermittent nutrient supply by different mechanisms. They possess an effective mechanism to take up phosphate, minimizing dilution and loss of phosphorus captured in the tank. Available phosphorus is taken up from the tank solution almost quantitatively, and the surplus not needed for current metabolism is accumulated in reserves, i.e. plants show luxury consumption. Young, developing leaves are preferentially supplied with this nutrient element. Taken together, these features allow epiphytes the efficient use of scarce and variable nutrient supplies. PMID:19033287

  18. Segregation mechanism of phosphorus in Ti-stabilized interstitial-free steel

    NASA Astrophysics Data System (ADS)

    Zhang, Xiliang; Liu, Tao

    2015-07-01

    The grain boundary segregation of phosphorus in an interstitial-free (IF) steel aged for different times at 600 and 720 °C was investigated using Auger electron spectroscopy. Results revealed that a significant degree of phosphorus segregation occurred during annealing for Ti-stabilized IF steel with 0.045 wt% bulk content of phosphorus. In addition, the segregation degree increased with increased holding time. The segregation behavior of phosphorus in IF steel was analyzed based on the theory of grain boundary segregation, along with the present experimental data and previous results. The phosphorus segregation had equilibrium segregation characteristics, and the bulk concentration of phosphorus and holding temperature strongly influenced the final grain boundary segregation concentration of phosphorus in IF steel during annealing. Furthermore, the segregation level of phosphorus substantially decreased with increased annealing temperature or decreased bulk concentration of phosphorus. Results of theoretical calculation were consistent with the experimental ones, indicating that the grain boundary segregation behavior of phosphorus in IF steel during annealing can be qualitatively and quantitatively explained by the theory of equilibrium segregation.

  19. Effects of Simulated Climate Conditions on Phosphorus Cycling in an Annual Grassland

    NASA Astrophysics Data System (ADS)

    Mellett, T.; Defforey, D.; Paytan, A.

    2012-12-01

    The Jasper Ridge Global Change Experiment is a long-term study of the effects of simulated climate change conditions on an annual grassland. The different treatments consist of elevated atmospheric CO2 levels, enhanced nitrate deposition, as well as higher temperatures and precipitation rates. The above ground vegetation from each plot is harvested and separated by species, with the dominant species being selected for analysis. The aim of this study is to investigate the effects of different climate conditions on the phosphorus content and phosphorus cycling in terrestrial plants. Phosphorus content in grass samples is determined using the colorimetric reaction (soluble reactive phosphorus content), as well as combustion and acid digestion (total phosphorus content). Since phosphorus only has one stable isotope, the ?18O signature in phosphate is used as a proxy to investigate phosphorus cycling in this ecosystem. These three tools will be combined and evaluated as indicators for phosphorus limitation in each respective treatment site and provide a better understanding of phosphorus cycling in annual grasslands and the potential effects of climate change on phosphorus cycling.

  20. 33 CFR 83.33 - Equipment for sound signals (Rule 33).

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ...2012-07-01 2012-07-01 false Equipment for sound signals (Rule 33). 83.33 Section 83...SECURITY INLAND NAVIGATION RULES RULES Sound and Light Signals § 83.33 Equipment for sound signals (Rule 33). (a) Vessels of...

  1. 33 CFR 83.33 - Equipment for sound signals (Rule 33).

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ...2014-07-01 2014-07-01 false Equipment for sound signals (Rule 33). 83.33 Section 83...SECURITY INLAND NAVIGATION RULES RULES Sound and Light Signals § 83.33 Equipment for sound signals (Rule 33). (a) Vessels of...

  2. 33 CFR 83.33 - Equipment for sound signals (Rule 33).

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ...2011-07-01 2011-07-01 false Equipment for sound signals (Rule 33). 83.33 Section 83...SECURITY INLAND NAVIGATION RULES RULES Sound and Light Signals § 83.33 Equipment for sound signals (Rule 33). (a) Vessels of...

  3. 33 CFR 83.33 - Equipment for sound signals (Rule 33).

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ...2010-07-01 2010-07-01 false Equipment for sound signals (Rule 33). 83.33 Section 83...SECURITY INLAND NAVIGATION RULES RULES Sound and Light Signals § 83.33 Equipment for sound signals (Rule 33). (a) Vessels of...

  4. 33 CFR 83.33 - Equipment for sound signals (Rule 33).

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ...2013-07-01 2013-07-01 false Equipment for sound signals (Rule 33). 83.33 Section 83...SECURITY INLAND NAVIGATION RULES RULES Sound and Light Signals § 83.33 Equipment for sound signals (Rule 33). (a) Vessels of...

  5. Polyaromatic hydrocarbons impair phosphorus transport by the arbuscular mycorrhizal fungus Rhizophagus irregularis.

    PubMed

    Calonne, Maryline; Fontaine, Joël; Tisserant, Benoît; Dupré de Boulois, Hervé; Grandmougin-Ferjani, Anne; Declerck, Stéphane; Lounès-Hadj Sahraoui, Anissa

    2014-06-01

    Phosphate uptake by plant roots is mainly mediated by arbuscular mycorrhizal fungi (AMF). However, the impact on phosphorus (P) transport of polycyclic aromatic hydrocarbons (PAH), persistent organic pollutants widely found in altered soils, is not known up today. Here, we monitored the Rhizophagus irregularis fungal growth and the fungal P transport ability from the extraradical mycelium to the host transformed chicory roots in the presence of anthracene and benzo[a]pyrene (B[a]P) and the combination of both PAH, under in vitro conditions. Firstly, our findings showed that PAH have detrimental effect on the fungal growth. The combination of both PAH was more toxic than each of the PAH individually due to synergistic effects. Secondly, PAH affected the P transport by the fungus from the medium to the roots. This was evidenced by either the decrease in (33)P quantity transported in the roots as well as the decrease in acid phosphatase activity in the mycorrhizal roots. Moreover, the fungal alkaline phosphatase activities remained constant in the extraradical mycelium as well as in the roots in the absence and in the presence of PAH. The GintPT and GiALP (encoding a P transporter and an alkaline phosphatase respectively) gene expressions were also found to be similar in the extraradical mycelium treated with PAH or not (control). These findings suggested that the P uptake by R. irregularis was not affected by PAH but probably the transport from the extraradical mycelium to the intraradical mycelium. PMID:24287265

  6. Glyphosate loss by runoff and its relationship with phosphorus fertilization.

    PubMed

    Sasal, María Carolina; Demonte, Luisina; Cislaghi, Andrea; Gabioud, Emmanuel A; Oszust, José D; Wilson, Marcelo G; Michlig, Nicolás; Beldoménico, Horacio R; Repetti, María Rosa

    2015-05-13

    The aim of this study was to evaluate the relationship between glyphosate and phosphate fertilizer application and their contribution to surface water runoff contamination. The study was performed in Aquic Argiudoll soil (Tezanos Pinto series). Four treatments were assessed on three dates of rainfall simulation after fertilizer and herbicide application. The soluble phosphorus in runoff water was determined by a colorimetric method. For the determination of glyphosate and aminomethylphosphonic acid (AMPA), a method based on fluorenylmethyloxycarbonyl (FMOC) group derivatization, solid phase extraction (SPE) purification, and ultrahigh-performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS) was employed. The application of phosphorus fertilizer resulted in an increased loss of glyphosate by runoff after 1 day of application. These results suggest the need for further study to understand the interactions and to determine appropriate application timing with the goal of reducing the pollution risk by runoff. PMID:25775388

  7. Calcium, phosphorus, and bone metabolism in the fetus and newborn.

    PubMed

    Kovacs, Christopher S

    2015-11-01

    The placenta actively transports minerals whereas the intestines and kidneys may be nonessential for fetal mineral homeostasis. Mineral concentrations are higher in fetal blood than in adults in order for the developing skeleton to accrete adequate mineral content. Fetal bone development and serum mineral regulation are dependent upon parathyroid hormone (PTH) and PTH-related protein (PTHrP), but not calcitriol, fibroblast growth factor-23, calcitonin, or the sex steroids. After birth, a switch from fetal to neonatal regulatory mechanisms is triggered by loss of the placental calcium infusion, onset of a breathing, and a postnatal fall in serum calcium and rise in phosphorus. This is followed by an increase in PTH, then a rise in calcitriol, and developmental changes in kidneys and intestines. Serum calcium increases and phosphorus declines over days. The intestines become the main source of mineral, while kidneys reabsorb mineral, and bone turnover contributes additional mineral to the circulation. PMID:26363942

  8. Innovations in steelmaking technology and hidden phosphorus flows.

    PubMed

    Matsubae, Kazuyo; Yamasue, Eiji; Inazumi, Tadahiro; Webeck, Elizabeth; Miki, Takahiro; Nagasaka, Tetsuya

    2016-01-15

    This article will outline the historical transition in the flow of phosphorus in steelmaking technology, and examine the current and future phosphorus flow in steel production and the peripheral steelmaking processes. History provides many instances of innovative changes in steelmaking processes driven by various issues associated with raw materials which emerged over time, such as supply, quality and cost issues. The major steel countries with a long history, including Sweden and Japan, have shown flexibility in their ability to adapt to the changes in the value of resources and geopolitical conditions over times, and have enacted survival resource utilization measures over many centuries, leading to improvements in their respective steelmaking processes. Considering these success stories, it stands to reason that the ideal state of steelmaking is one with a clear stance with regard to resource policy. PMID:26541457

  9. Power Dissipation and Electrical Breakdown in Black Phosphorus.

    PubMed

    Engel, Michael; Steiner, Mathias; Han, Shu-Jen; Avouris, Phaedon

    2015-10-14

    We report operating temperatures and heating coefficients measured in a multilayer black phosphorus device as a function of injected electrical power. By combining micro-Raman spectroscopy and electrical transport measurements, we have observed a linear temperature increase up to 600 K at a power dissipation rate of 0.896 K ?m(3)/mW. By further increasing the bias voltage, we determined the threshold power and temperature for electrical breakdown and analyzed the fracture in the black phosphorus layer that caused the device failure by means of scanning electron microscopy and atomic force microscopy. The results will benefit the research and development of electronics and optoelectronics based on novel two-dimensional materials. PMID:26348293

  10. Power Dissipation and Electrical Breakdown in Black Phosphorus

    NASA Astrophysics Data System (ADS)

    Engel, Michael; Steiner, Mathias; Han, Shu-Jen; Avouris, Phaedon

    2015-10-01

    We report operating temperatures and heating coefficients measured in a multi-layer black phosphorus device as a function of injected electrical power. By combining micro-Raman spectroscopy and electrical transport measurements, we have observed a linear temperature increase up to 600K at a power dissipation rate of 0.896K\\mu m^3/mW. By further increasing the bias voltage, we determined the threshold power and temperature for electrical breakdown and analyzed the fracture in the black phosphorus layer that caused the device failure by means of scanning electron microscopy and atomic force microscopy. The results will benefit the research and development of electronics and optoelectronics based on novel two-dimensional materials.

  11. Phosphorus diffusion in germanium following implantation and excimer laser annealing

    NASA Astrophysics Data System (ADS)

    Wang, Chen; Li, Cheng; Huang, Shihao; Lu, Weifang; Yan, Guangming; Zhang, Maotian; Wu, Huanda; Lin, Guangyang; Wei, Jiangbin; Huang, Wei; Lai, Hongkai; Chen, Songyan

    2014-05-01

    We focus our study on phosphorus diffusion in ion-implanted germanium after excimer laser annealing (ELA). An analytical model of laser annealing process is developed to predict the temperature profile and the melted depth in Ge. Based on the heat calculation of ELA, a phosphorus diffusion model has been proposed to predict the dopant profiles in Ge after ELA and fit SIMS profiles perfectly. A comparison between the current-voltage characteristics of Ge n+/p junctions formed by ELA at 250 mJ/cm2 and rapid thermal annealing at 650 °C for 15 s has been made, suggesting that ELA is promising for high performance Ge n+/p junctions.

  12. RNA function and phosphorus use by photosynthetic organisms

    PubMed Central

    Raven, John A.

    2013-01-01

    Phosphorus (P) in RNA accounts for half or more of the total non-storage P in oxygenic photolithotrophs grown in either P-replete or P-limiting growth conditions. Since many natural environments are P-limited for photosynthetic primary productivity, and peak phosphorus fertilizer production is inevitable, the paper analyses what economies in P allocation to RNA could, in principle, increase P-use efficiency of growth (rate of dry matter production per unit organism P). The possibilities of decreasing P allocation to RNA without decreasing growth rate include (1) more widespread down-regulation of RNA production in P-limited organisms, (2) optimal allocation of P to RNA, both spatially among cell compartments and organs, and temporally depending on the stage of growth, and (3) a constant rate of protein synthesis through the diel cycle. Acting on these suggestions would, however, be technically demanding. PMID:24421782

  13. Magnesium and phosphorus distribution in the avian eggshell.

    PubMed

    Cusack, M; Fraser, A C; Stachel, T

    2003-01-01

    Magnesium and phosphorus are major inorganic constituents of the avian eggshell. The Mg/Ca ratio has been used as a palaeothermometer in a range of calcite biominerals. Eggshells provide the opportunity to examine the Mg/Ca ratio of a calcite biomineral produced in a constant temperature environment. Mg distribution is not constant throughout the shell, decreasing from nucleation until after fusion of the mammillary caps and then increasing to termination. This indicates that temperature of deposition is not the only factor controlling the Mg content of this biomineral system. There is a greater increase in magnesium concentration in the outer region of eggshells from older birds. The variation in magnesium concentration does not appear to correlate with organic content. Phosphorus occurs in the outer quarter of the eggshell and rises to termination and is therefore not confined to cuticular vesicles. PMID:12524034

  14. Microbial dissolved organic phosphorus utilization in the Hudson River Estuary

    SciTech Connect

    Ammerman, J.W. ); Angel, D.L. )

    1990-01-09

    The Hudson River Estuary has large inputs of phosphorus and other nutrients from sewage discharge. Concentrations of soluble reactive phosphorus (SRP) reach at least 4 uM during the summer low-flow period. Biological utilization of phosphorus and other nutrients is usually minimal because of the high turbidity and short residence time of the water. Therefore SRP is normally a conservative tracer of salinity, with maximum concentrations found off Manhattan and decreasing to the north. Despite this abundance of SRP, some components of the dissolved organic phosphorus (DOP) appear to be rapidly cycled by microbes. The objective of this study was to measure this DIP cycling during both the high- and low-flow periods. We measured the concentrations of SRP and DOP, the SRP turnover rate, algal and bacterial biomass, and the substrate turnover rates of two microbial cell-surface phosphatases, alkaline phosphatase (AP) and 5[prime] - nucleotidase (5PN). SRP concentrations ranged from about 0.5-4 uM, DOP was usually less than 1 uM. SRP and AP turnover were slow (generally < 5%/h), but 5PN substrate turnover was high with a median rate of 100%/h. Furthermore, over 30% of the phosphate hydrolyzed by 5PN was immediately taken up. If the nucleotide-P concentration is conservatively assumed to be 5 nM, than the rate of phosphate utilization from DOP is nearly equal to that from SRP. That is paradoxical considering the large SRP concentration, but suggests that much of this SRP may be biologically unavailable due to complexation with iron or other processes.

  15. Observations of Circumstellar Thermochemical Equilibrium: The Case of Phosphorus

    NASA Technical Reports Server (NTRS)

    Milam, Stefanie N.; Charnley, Steven B.

    2011-01-01

    We will present observations of phosphorus-bearing species in circumstellar envelopes, including carbon- and oxygen-rich shells 1. New models of thermochemical equilibrium chemistry have been developed to interpret, and constrained by these data. These calculations will also be presented and compared to the numerous P-bearing species already observed in evolved stars. Predictions for other viable species will be made for observations with Herschel and ALMA.

  16. Soil available phosphorus in a permanent grassland excessively fertilized

    NASA Astrophysics Data System (ADS)

    García Tomillo, Aitor; Valcárcel Armesto, Montserrat; Dafonte Dafonte, Jorge; Marinho, Mara de Andrade; Ramón Raposo, Juan; de Abreu, Cleide A.

    2013-04-01

    Phosphorus is an essential element for crop growth and it is necessary to maintain profitable agriculture. In agricultural areas with high cattle manure and/or slurry inputs, available soil P levels are in excess of crop needs, so they had the potential to enrich surface water by runoff, which may trigger eutrophication. This is the case in Galicia, a temperate humid region in north-western of Spain. Soil nutrient testing is a management tool that can help accurately determine the available nutrient status of soils and guide the efficient use of fertilizers. Differences in soil phosphorus (P) contents measured by various techniques may have agronomic and environmental implications. The aim of this study was to analyze the spatial variability of available phosphorus in a permanent grassland field fertilized with organic manure. determined both after exchange resin and Mehlich 3 extraction. The experimental site was located at Castro de Ribeira de Lea, Lugo province, Spain. The studied soil was characterized by a loamy to loam sandy A horizon, rich in organic matter over tertizry-quaternary sediments. Soil was sampled at two successive depths, 0-20 cm and > 20 cm over a 6 ha field. Eighty soil samples were collected. Available P was colorimetrically determined after extraction with Mehlich 3 and exchangeable resin. Mean available P contents extracted using Mehlich 3 and resin were 29.9 and 108.8 mg.kg-1, respectively. Phosphorus extracted by Mehlich 3 ranged from 40.2 to 203.1 mg.kg-1, whereas resin extractable P ranged from 12.4 to 61 mg.kg-1 . These test results indicate excess P all over the studied field. Spatial variability of P over the experimental field was analyzed using geostatistics.

  17. Soil, Water and Forage Testing Laboratory Phosphorus recommendations applicable for

    E-print Network

    SWEET POTATOES 155 140 120 105 90 75 60 45 30 15 0 Mehlich III by ICP phosphorus (ppm or mg/kg) in Soil PEPPERS, CHILE 105 95 80 70 60 50 40 30 20 10 0 PEPPERS,BELL 105 95 80 70 60 50 40 30 20 10 0 POTATOES (EARLY VARIETY) 250 225 205 185 165 145 120 100 80 60 40 20 0 POTATOES (LATE VARIETY) 250 225 205 185 165

  18. Phosphorus homeostasis in legume nodules as an adaptive strategy to phosphorus deficiency.

    PubMed

    Sulieman, Saad; Tran, Lam-Son Phan

    2015-10-01

    Legumes have a significant role in effective management of fertilizers and improving soil health in sustainable agriculture. Because of the high phosphorus (P) requirements of N2-fixing nodule, P deficiency represents an important constraint for legume crop production, especially in tropical marginal countries. P deficiency is an important constraint for legume crop production, especially in poor soils present in many tropical degraded areas. Unlike nitrogen, mineral P sources are nonrenewable, and high-grade rock phosphates are expected to be depleted in the near future. Accordingly, developing legume cultivars with effective N2 fixation under P-limited conditions could have a profound significance for improving agricultural sustainability. Legumes have evolved strategies at both morphological and physiological levels to adapt to P deficiency. Molecular mechanisms underlying the adaptive strategies to P deficiency have been elucidated in legumes. These include maintenance of the P-homeostasis in nodules as a main adaptive strategy for rhizobia-legume symbiosis under P deficiency. The stabilization of P levels in the symbiotic tissues can be achieved through several mechanisms, including elevated P allocation to nodules, formation of a strong P sink in nodules, direct P acquisition via nodule surface and P remobilization from organic-P containing substances. The detailed biochemical, physiological and molecular understanding will be essential to the advancement of genetic and molecular approaches for enhancement of legume adaptation to P deficiency. In this review, we evaluate recent progress made to gain further and deeper insights into the physiological, biochemical and molecular reprogramming that legumes use to maintain P-homeostasis in nodules during P scarcity. PMID:26398789

  19. Laboratory-determined Phosphorus Flux from Lake Sediments as a Measure of Internal Phosphorus Loading

    PubMed Central

    Ogdahl, Mary E.; Steinman, Alan D.; Weinert, Maggie E.

    2014-01-01

    Eutrophication is a water quality issue in lakes worldwide, and there is a critical need to identify and control nutrient sources. Internal phosphorus (P) loading from lake sediments can account for a substantial portion of the total P load in eutrophic, and some mesotrophic, lakes. Laboratory determination of P release rates from sediment cores is one approach for determining the role of internal P loading and guiding management decisions. Two principal alternatives to experimental determination of sediment P release exist for estimating internal load: in situ measurements of changes in hypolimnetic P over time and P mass balance. The experimental approach using laboratory-based sediment incubations to quantify internal P load is a direct method, making it a valuable tool for lake management and restoration. Laboratory incubations of sediment cores can help determine the relative importance of internal vs. external P loads, as well as be used to answer a variety of lake management and research questions. We illustrate the use of sediment core incubations to assess the effectiveness of an aluminum sulfate (alum) treatment for reducing sediment P release. Other research questions that can be investigated using this approach include the effects of sediment resuspension and bioturbation on P release. The approach also has limitations. Assumptions must be made with respect to: extrapolating results from sediment cores to the entire lake; deciding over what time periods to measure nutrient release; and addressing possible core tube artifacts. A comprehensive dissolved oxygen monitoring strategy to assess temporal and spatial redox status in the lake provides greater confidence in annual P loads estimated from sediment core incubations. PMID:24637715

  20. Determination of phosphorus source coefficients for organic phosphorus sources: laboratory studies.

    PubMed

    Leytem, A B; Sims, J T; Coale, F J

    2004-01-01

    Phosphorus losses in runoff from application of manures and biosolids to agricultural land are implicated in the degradation of water quality in the Chesapeake and Delaware Inland Bays. We conducted an incubation study to determine the relative P solubility and bioavailability, referred to as P source coefficients (PSCs), for organic P sources, which are typically land-applied in the Mid-Atlantic USA. Nine organic and one inorganic (KH2PO4) P amendments were applied to an Evesboro loamy sand (mesic, coated Typic Quartzipsamments) at a rate of 60 mg P kg(-1) and incubated for 8 wk with subsamples analyzed at 2 and 8 wk. There was an increase in Mehlich-3 P (M3-P), water-soluble P (WS-P), iron-oxide strip extractable P (FeO-P), and Mehlich-3 P saturation ratio (M3-PSR) with P additions, which varied by P source. The trend of relative extractable WS-P, FeO-P, and M3-P generally followed the pattern: inorganic P > liquid and deep pit manures > manures and biosolids treated with metal salts or composted. We found significant differences in the availability of P from varying organic P sources. The use of PSCs may be beneficial when determining the risk of P losses from land application of manures and other organic P sources and could be used in risk assessments such as a P site index. These PSCs may also be useful for determining P application rates when organic P sources are applied to P deficient soils for use as a fertilizer source. PMID:14964394