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  1. 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... Systems § 862.1580 Phosphorus (inorganic) test system. (a) Identification. A phosphorus (inorganic) test system is a device intended to measure inorganic phosphorus in serum, plasma, and urine. Measurements...

  2. 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... Systems § 862.1580 Phosphorus (inorganic) test system. (a) Identification. A phosphorus (inorganic) test system is a device intended to measure inorganic phosphorus in serum, plasma, and urine. Measurements...

  3. 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... Systems § 862.1580 Phosphorus (inorganic) test system. (a) Identification. A phosphorus (inorganic) test system is a device intended to measure inorganic phosphorus in serum, plasma, and urine. Measurements...

  4. 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... Systems § 862.1580 Phosphorus (inorganic) test system. (a) Identification. A phosphorus (inorganic) test system is a device intended to measure inorganic phosphorus in serum, plasma, and urine. Measurements...

  5. 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... phosphorus (inorganic) are used in the diagnosis and treatment of various disorders, including...

  6. Phosphinate chemistry in the 21st century: a viable alternative to the use of phosphorus trichloride in organophosphorus synthesis.

    PubMed

    Montchamp, Jean-Luc

    2014-01-21

    Organophosphorus compounds are important in everyday applications ranging from agriculture to medicine and are used in flame retardants and other materials. Although organophosphorus chemistry is known as a mature and specialized area, researchers would like to develop new methods for synthesizing organophosphorus compounds to improve the safety and sustainability of these chemical processes. The vast majority of compounds that contain a phosphorus-carbon bond are manufactured using phosphorus trichloride (PCl3) as an intermediate. However, these reactions require chlorine, and researchers would like to avoid the use of PCl3 and develop safer chemistry that also decreases energy consumption and minimizes waste. Researchers have already proposed and discussed two primary strategies based on elemental phosphorus (P4 or Pred) or on phosphine (PH3) as alternatives to PCl3. However, phosphinates, an important class of phosphorus compounds defined as any compound with a phosphorus atom attached to two oxygens, R(1)R(2)P(O)(OR) (R(1)/R(2) = hydrogen/carbon), offer another option. This Account discusses the previously neglected potential of these phosphinates as replacements of PCl3 for the preparation of organophosphorus compounds. Because of their strong reductive properties, industry currently uses the simplest members of this class of compounds, hypophosphites, for one major application: electroless plating. In comparison with other proposed PCl3 surrogates, hypophosphorous derivatives can offer improved stability, lower toxicity, higher solubility, and increased atom economy. When their reducing power is harnessed to form phosphorus-carbon or phosphorus-oxygen bonds, these compounds are also rich and versatile precursors to organophosphorus compounds. This Account examines the use of transition metal-catalyzed reactions such as cross-coupling and hydrophosphinylation for phosphorus-carbon bond formation. Because the most important industrial organophosphorus compounds

  7. Glacial atmospheric phosphorus deposition

    NASA Astrophysics Data System (ADS)

    Kjær, Helle Astrid; Dallmayr, Remi; Gabrieli, Jacopo; Goto-Azuma, Kumiko; Hirabayashi, Motohiro; Svensson, Anders; Vallelonga, Paul

    2016-04-01

    Phosphorus in the atmosphere is poorly studied and thus not much is known about atmospheric phosphorus and phosphate transport and deposition changes over time, though it is well known that phosphorus can be a source of long-range nutrient transport, e.g. Saharan dust transported to the tropical forests of Brazil. In glacial times it has been speculated that transport of phosphorus from exposed shelves would increase the ocean productivity by wash out. However whether the exposed shelf would also increase the atmospheric load to more remote places has not been investigated. Polar ice cores offer a unique opportunity to study the atmospheric transport of aerosols on various timescales, from glacial-interglacial periods to recent anthropogenic influences. We have for the first time determined the atmospheric transport of phosphorus to the Arctic by means of ice core analysis. Both total and dissolved reactive phosphorus were measured to investigate current and past atmospheric transport of phosphorus to the Arctic. Results show that glacial cold stadials had increased atmospheric total phosphorus mass loads of 70 times higher than in the past century, while DRP was only increased by a factor of 14. In the recent period we find evidence of a phosphorus increase over the past 50 yrs in ice cores close to human occupation likely correlated to forest fires. References: Kjær, Helle Astrid, et al. "Continuous flow analysis method for determination of dissolved reactive phosphorus in ice cores." Environmental science & technology 47.21 (2013): 12325-12332. Kjær, Helle Astrid, et al. "Greenland ice cores constrain glacial atmospheric fluxes of phosphorus." Journal of Geophysical Research: Atmospheres120.20 (2015).

  8. Phosphorus Test

    MedlinePlus

    ... be limited. Home Visit Global Sites Search Help? Phosphorus Share this page: Was this page helpful? Also ... else I should know? How is it used? Phosphorus tests are most often ordered along with other ...

  9. A Green, Expeditious, One-Pot Synthesis of 3, 4-Dihydropyrimidin-2(1H)-ones Using a Mixture of Phosphorus Pentoxide-Methanesulfonic Acid at Ambient Temperature

    PubMed Central

    Borse, Amulrao; Patil, Mahesh; Patil, Nilesh; Shinde, Rohan

    2012-01-01

    An expeditious, one-pot method for the synthesis of 3,4-dihydropyrimidin-2(1H)-ones using a mixture of phosphorus pentoxide-methanesulfonic acid (Eaton's reagent) at room temperature under solvent-free conditions is described. The salient features of this method include short reaction time, green aspects, high yields, and simple procedure. PMID:24052843

  10. 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

  11. Dietary phosphorus, serum phosphorus, and cardiovascular disease.

    PubMed

    Menon, Madhav C; Ix, Joachim H

    2013-10-01

    Recent epidemiologic studies have linked higher serum phosphorus concentrations to cardiovascular disease (CVD) events and mortality. This association has been identified in the general population and in those with chronic kidney disease (CKD). The risk of adverse outcomes appears to begin with phosphorus concentrations within the upper limit of the normal reference range. Multiple experimental studies have suggested pathogenetic mechanisms that involve direct and indirect effects of high phosphorus concentrations to explain these associations. Drawing from these observations, guideline-forming agencies have recommended that serum phosphorus concentrations be maintained within the normal reference range in patients with CKD and that dietary phosphorus restriction or use of intestinal phosphate binders should be considered to achieve this goal. However, outside the dialysis population, the links between dietary phosphorus intake and serum phosphorus concentrations, and dietary phosphorus intake and CVD events, are uncertain. With specific reference to the nondialysis populations, this review discusses the available data linking dietary phosphorus intake with serum phosphorus concentrations and CVD events.

  12. Phosphorus in diet

    MedlinePlus

    According to Institute of Medicine recommendations, the recommended dietary intakes of phosphorus are as follows: 0 to 6 ... Food and Nutrition Board, Institute of Medicine. DRI Dietary Reference Intakes for Calcium, Phosphorus, Magnesium, Vitamin D, and Fluoride . ...

  13. Phosphorus poisoning in waterfowl

    USGS Publications Warehouse

    Coburn, D.R.; DeWitt, J.B.; Derby, J.V.; 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.

  14. Biogeochemistry: The fate of phosphorus

    NASA Astrophysics Data System (ADS)

    Némery, Julien; Garnier, Josette

    2016-05-01

    Phosphorus is essential for food production, but it is also a key cause of eutrophication. Estimates of phosphorus flux for the past 40-70 years reveal that large river basins can experience phases of phosphorus accumulation and depletion.

  15. The Global Phosphorus Cycle

    NASA Astrophysics Data System (ADS)

    Ruttenberg, K. C.

    2003-12-01

    Phosphorus is an essential nutrient for all life forms. It is a key player in fundamental biochemical reactions (Westheimer, 1987) involving genetic material (DNA, RNA) and energy transfer (ATP), and in structural support of organisms provided by membranes (phospholipids) and bone (the biomineral hydroxyapatite). Photosynthetic organisms utilize dissolved phosphorus, carbon, and other essential nutrients to build their tissues using energy from the Sun. Biological productivity is contingent upon the availability of phosphorus to these simple organisms that constitute the base of the food web in both terrestrial and aquatic systems. (For reviews of P-utilization, P-biochemicals, and pathways in aquatic plants, see Fogg (1973), Bieleski and Ferguson (1983), and Cembella et al. (1984a, 1984b).)Phosphorus locked up in bedrock, soils, and sediments is not directly available to organisms. Conversion of unavailable forms to dissolved orthophosphate, which can be directly assimilated, occurs through geochemical and biochemical reactions at various stages in the global phosphorus cycle. Production of biomass fueled by P-bioavailability results in the deposition of organic matter in soils and sediments, where it acts as a source of fuel and nutrients to microbial communities. Microbial activity in soils and sediments, in turn, strongly influences the concentration and chemical form of phosphorus incorporated into the geological record.The global phosphorus cycle has four major components: (i) tectonic uplift and exposure of phosphorus-bearing rocks to the forces of weathering; (ii) physical erosion and chemical weathering of rocks producing soils and providing dissolved and particulate phosphorus to rivers; (iii) riverine transport of phosphorus to lakes and the ocean; and (iv) sedimentation of phosphorus associated with organic and mineral matter and burial in sediments (Figure 1). The cycle begins anew with uplift of sediments into the weathering regime.

  16. Phosphorus recovery from wastes

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Phosphorus (P) is an important macro-nutrient essential for all living organisms and phosphate rock is the main raw material for all inorganic P fertilizers. It is expected that there will be a P peak and resulting P fertilizer shortage in near future. In general, phosphorus use efficiency is low a...

  17. 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.

  18. 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

  19. Phosphorus chemistry in everyday living

    SciTech Connect

    Toy, D.F.; Walsh, E.F.

    1987-01-01

    This book brings to life the versatility of phosphorus and its compounds and is filled with personal anecdotes and experiences of the authors. Covers the uses of phosphorus in matches and warfare; phosphates and food, fertilizers, cleaners, and detergents; organic phosphorus nerve gases and insecticides. Also discusses phosphoric acids, organic phosphorus polymers, deoxyribonucleic and ribonucleic acids and adenosine triphosphate.

  20. Phosphorus, phosphorous, and phosphate.

    PubMed

    Iheagwara, O Susan; Ing, Todd S; Kjellstrand, Carl M; Lew, Susie Q

    2013-10-01

    This article distinguishes the terms "phosphorus, phosphorous, and phosphate" which are frequently used interchangeably. We point out the difference between phosphorus and phosphate, with an emphasis on the unit of measure. Expressing a value without the proper name or unit of measure may lead to misunderstanding and erroneous conclusions. We indicate why phosphate must be expressed as milligrams per deciliter or millimoles per liter and not as milliequivalents per liter. Therefore, we elucidate the distinction among the terms "phosphorus, phosphorous, and phosphate" and the importance of saying precisely what one really means.

  1. Phosphorus blood test

    MedlinePlus

    ... serum; HPO4 -2 ; PO4 -3 ; Inorganic phosphate; Serum phosphorus ... that may affect the test. These medicines include water pills (diuretics), antacids, and laxatives. DO NOT stop taking any medicine before talking to your provider.

  2. Relative phosphorus requirements of three strains of White Leghorn cockerels.

    PubMed

    Christmas, R B; Harms, R H

    1978-03-01

    Three strains of White Leghorn Cockerels were fed a degerminated corn meal diet supplemented with graded levels of phosphorus. The basal diet which contained .30% phosphorus and .21% calcium was adjusted to contain added phosphorus levels of 0, .05, .10, or .15%, with calcium levels of .49, .47, .57 and .61%, respectively. At the end of a 21-day trial period, birds were group weighed by replicate, and four birds from each replicate sacrificed for bone ash determinations. The experiment was repeated one time. Maximum body weights of Babcock B-300 and Hyline W-36 chicks was attained at the .10% supplemental phosphorus level; whereas Kimber K-137 chick body weight data indicated a response beyond this point to the .15% level. Bone ash data indicated that there may be a difference in phosphorus requirement and/or utilization among the three strains. There was no significant response beyond the .10% supplemental phosphorus level when tibia ash values of the B-300 and W-36 chicks were analyzed. A significant response in ash values was noted, however, to the .15% supplemental phosphorus level with K-137 chicks.

  3. 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

  4. Phosphorus in prebiotic chemistry.

    PubMed

    Schwartz, Alan W

    2006-10-29

    The prebiotic synthesis of phosphorus-containing compounds-such as nucleotides and polynucleotides-would require both a geologically plausible source of the element and pathways for its incorporation into chemical systems on the primitive Earth. The mineral apatite, which is the only significant source of phosphate on Earth, has long been thought to be problematical in this respect due to its low solubility and reactivity. However, in the last decade or so, at least two pathways have been demonstrated which would circumvent these perceived problems. In addition, recent results would seem to suggest an additional, extraterrestrial source of reactive phosphorus. It appears that the 'phosphorus problem' is no longer the stumbling block which it was once thought to be. PMID:17008215

  5. 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.

  6. 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 2392 Gg P in 2005, half of which accumulated in agricultural soils (924 Gg) and half was lost as waste (1217 Gg). Net accumulation was 4.9 kg P/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 (655 Gg) 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.

  7. 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.

  8. Ultrafast Nonlinear Excitation Dynamics of Black Phosphorus Nanosheets from Visible to Mid-Infrared.

    PubMed

    Wang, Kangpeng; Szydłowska, Beata M; Wang, Gaozhong; Zhang, Xiaoyan; Wang, Jing Jing; Magan, John J; Zhang, Long; Coleman, Jonathan N; Wang, Jun; Blau, Werner J

    2016-07-26

    The recent progress on black phosphorus makes it a promising candidate material for broadband nanophotonic devices, especially operating in the mid-infrared spectral region. Here, the excited carrier dynamics and nonlinear optical response of unoxidized black phosphorus nanosheets and their wavelength dependence were systematically studied from 800 nm to 2.1 μm. The wavelength-dependent relaxation times of black phosphorus nanosheets are determined to be 360 fs to 1.36 ps with photon energies from 1.55 to 0.61 eV. In a comparative study with graphene, we found that black phosphorus has a faster carrier relaxation in near- and mid-infrared region. With regard to nonlinear optical absorption, the response of black phosphorus significantly increases from near- to mid-infrared, and black phosphorus is also confirmed to be better as saturable absorber to MoS2 in infrared region. PMID:27281449

  9. Ultrafast Nonlinear Excitation Dynamics of Black Phosphorus Nanosheets from Visible to Mid-Infrared.

    PubMed

    Wang, Kangpeng; Szydłowska, Beata M; Wang, Gaozhong; Zhang, Xiaoyan; Wang, Jing Jing; Magan, John J; Zhang, Long; Coleman, Jonathan N; Wang, Jun; Blau, Werner J

    2016-07-26

    The recent progress on black phosphorus makes it a promising candidate material for broadband nanophotonic devices, especially operating in the mid-infrared spectral region. Here, the excited carrier dynamics and nonlinear optical response of unoxidized black phosphorus nanosheets and their wavelength dependence were systematically studied from 800 nm to 2.1 μm. The wavelength-dependent relaxation times of black phosphorus nanosheets are determined to be 360 fs to 1.36 ps with photon energies from 1.55 to 0.61 eV. In a comparative study with graphene, we found that black phosphorus has a faster carrier relaxation in near- and mid-infrared region. With regard to nonlinear optical absorption, the response of black phosphorus significantly increases from near- to mid-infrared, and black phosphorus is also confirmed to be better as saturable absorber to MoS2 in infrared region.

  10. Phosphorus budget of redeye mullet ( Liza haematocheila T. & S.) under graded feeding levels

    NASA Astrophysics Data System (ADS)

    Kang, Bin; Xian, Weiwei; Wu, Yunfei

    2006-09-01

    Experiment on phosphorus budget of redeye mullet ( Liza haematocheila T. & S.) was conducted at water temperature 21°C and salinity 33. The results showed that the growth phosphorus (phosphorus that allocated into growth, GP) increased from -30.84% to 15.83 % by feeding on graded amount of diets (starvation, 1%, 2%, 3%, 4% body weight and satiation). The GP linearly increased with feeding levels (FL) as GP (mg)=-0.785 +0.604 FL, and at satiation the relationship between GP and body weight (BW) was GP (mg)=1.5991 BW 0.7685. In the budget, IP (intake phosphorus)= GP+ FP (faecal phosphorus)+ EP (excretion phosphorus). FP showed an irregular tendency with different feeding levels, and EP decreased with increasing feeding levels but rebound at satiation. The P budget at satiation was 100 IP=15.84 GP+64.62 FP+19.55 EP.

  11. 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.

  12. Characterization and sonochemical synthesis of black phosphorus from red phosphorus

    NASA Astrophysics Data System (ADS)

    Aldave, Sandra H.; Yogeesh, Maruthi N.; Zhu, Weinan; Kim, Joonseok; Sonde, Sushant S.; Nayak, Avinash P.; Akinwande, Deji

    2016-03-01

    Phosphorene is a new two-dimensional material which is commonly prepared by exfoliation from black phosphorus bulk crystals that historically have been synthesized from white phosphorus under high-pressure conditions. The few layers of phosphorene have a direct band gap in the range of 0.3-2 eV and high mobility at room temperature comparable to epitaxial graphene. These characteristics can be used for the design of high speed digital circuits, radio frequency circuits, flexible and printed systems, and optoelectronic devices. In this work, we synthesized black phosphorus from red phosphorus, which is a safer solid precursor, using sonochemistry. Furthermore, via a variety of microscopy and spectroscopy techniques, we report characterization results of the sonochemically synthesized black phosphorus in addition to the commercial black phosphorus. Finally, we describe the air stability of black phosphors and the crystalline structure of the synthesized material. This is the first result of sonochemical or solution-based synthesis of black phosphorus based on readily available low-cost red phosphorus. This solution-based synthesis of black phosphorus is suitable for printable applications of nanomaterial.

  13. Two-Dimensional Phosphorus Porous Polymorphs with Tunable Band Gaps.

    PubMed

    Zhuo, Zhiwen; Wu, Xiaojun; Yang, Jinlong

    2016-06-01

    Exploring stable two-dimensional (2D) crystalline structures of phosphorus with tunable properties is of considerable importance partly due to the novel anisotropic behavior in phosphorene and potential applications in high-performance devices. Here, 21 new 2D phosphorus allotropes with porous structure are reported based on topological modeling method and first-principles calculations. We establish that stable 2D phosphorus crystals can be obtained by topologically assembling selected phosphorus monomer, dimer, trimer, tetramer, and hexamer. Nine of reported structures are predicted to be more stable than white phosphorus. Their dynamic and thermal stabilities are confirmed by the calculated vibration spectra and Born-Oppenheimer molecular dynamic simulation at temperatures up to 1500 K. These phosphorus porous polymorphs have isotropic mechanic properties that are significantly softer than phosphorene. The electronic band structures calculated with the HSE06 method indicate that new structures are semiconductors with band gaps ranging widely from 0.15 to 3.42 eV, which are tuned by the basic units assembled in the network. Of particular importance is that the position of both conduction and valence band edges of some allotropes matches well with the chemical reaction potential of H2/H(+) and O2/H2O, which can be used as element photocatalysts for visible-light-driven water splitting. PMID:27171121

  14. Process for improving phosphorus-vanadium oxide and phosphorus-vanadium-co-metal oxide catalysts

    SciTech Connect

    Edwards, R.C.

    1987-10-20

    A process is described for the improvement of a vanadium-phosphorus-oxygen catalyst having a phosphorus to vanadium atomic ratio of about 2:1 to about 0.8:1 which catalyst is present on a catalyst bed having a portion therof containing an initial exotherm of reaction. The catalyst is suitable for use in the manufacture of maleic anhydride from a feed gas stream comprising C/sub 4/ hydrocarbons, benzene, or butane which process comprises: applying to the catalyst bed, simultaneously with introduction of the feed gas stream thereon, water and a phosphorus compound in an amount sufficient to initiate (a) deactivation of the portion of the catalyst containing the initial exotherm, and (b) formation of a new exotherm downstream in the catalyst bed from the initial exotherm, and thereafter reducing or discontinuing application of the phosphorus compound at a point in time when the initial exotherm portion of the catalyst bed is still undergoing deactivation, thereby allowing the partially deactivated exotherm portion to reactivate by producing a more isothermal catalyst bed.

  15. Preparation of high purity phosphorus

    DOEpatents

    Rupp, Arthur F.; Woo, David V.

    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.

  16. Synthesis of pure phosphorus nanostructures.

    PubMed

    Winchester, Richard A L; Whitby, Max; Shaffer, Milo S P

    2009-01-01

    To Bi or not to Bi? The synthesis of phosphorus nanorods of two differing morphologies is reported, in both the presence and absence of a bismuth catalyst. Not only do these materials represent a new class of elemental nanorods but they also give valuable insight into the complex allotropy of phosphorus. PMID:19180611

  17. Extraction of soil organic phosphorus.

    PubMed

    Turner, Benjamin L; Cade-Menun, Barbara J; Condron, Leo M; Newman, Susan

    2005-04-15

    Organic phosphorus is an important component of soil biogeochemical cycles, but must be extracted from soil prior to analysis. Here we critically review the extraction of soil organic phosphorus, including procedures for quantification, speciation, and assessment of biological availability. Quantitative extraction conventionally requires strong acids and bases, which inevitably alter chemical structure. However, a single-step procedure involving sodium hydroxide and EDTA (ethylenediaminetetraacetate) is suitable for most soils and facilitates subsequent speciation by nuclear magnetic resonance spectroscopy. Analysis of extracts by molybdate colorimetry is a potential source of error in all procedures, because organic phosphorus is overestimated in the presence of inorganic polyphosphates or complexes between inorganic phosphate and humic substances. Sequential extraction schemes fractionate organic phosphorus based on chemical solubility, but the link to potential bioavailability is misleading. Research should be directed urgently towards establishing extractable pools of soil organic phosphorus with ecological relevance.

  18. 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.

  19. [Bone and Nutrition. Bone and phosphorus intake].

    PubMed

    Arai, Hidekazu; Sakuma, Masae

    2015-07-01

    Phosphorus is necessary for bone mineralization. Although adequate phosphorus intake is essential for skeletal mineralization, it is reported that excessive phosphorus intake can induce deleterious effect on bone. Recently, since the Japanese diet has been westernized, phosphorus intake by the meat and dairy products has increased. Furthermore, along with the development of processed foods, excessive intake of inorganic phosphorus from food additives has become a problem. An adverse effect on parathyroid hormone (PTH) secretion from high phosphorus intake was seen only when calcium intake was inadequate. Dietary calcium to phosphorus ratio can be considered as one of the indicators that can predict the health of the bone.

  20. [Bone and Nutrition. Bone and phosphorus intake].

    PubMed

    Arai, Hidekazu; Sakuma, Masae

    2015-07-01

    Phosphorus is necessary for bone mineralization. Although adequate phosphorus intake is essential for skeletal mineralization, it is reported that excessive phosphorus intake can induce deleterious effect on bone. Recently, since the Japanese diet has been westernized, phosphorus intake by the meat and dairy products has increased. Furthermore, along with the development of processed foods, excessive intake of inorganic phosphorus from food additives has become a problem. An adverse effect on parathyroid hormone (PTH) secretion from high phosphorus intake was seen only when calcium intake was inadequate. Dietary calcium to phosphorus ratio can be considered as one of the indicators that can predict the health of the bone. PMID:26119308

  1. 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.

  2. Effects of diet and body size on phosphorus utilization of Liza haematocheila T. & S.

    NASA Astrophysics Data System (ADS)

    Kang, Bin; Xian, Weiwei; Wu, Yunfei

    2008-05-01

    A 21-d laboratory experiment was conducted to study, the phosphorus (P) utilization of two different diets by redlip mullet Liza haematocheila T. & S. Sand-filtered water in salinity 30 and temperature 25°C was used. Twenty-nine fish individuals were divided into three groups: 11 to group 1 (G1) fed on diet 1, 11 to group 2 (G2) fed on diet 2, and 7 to contrast group. Diet 1 was a commercial feed, more valuable in nutrition than diet 2 that similar to natural detritus. The results show the intake phosphorus (IP) of G1 was significantly higher than that of G2, and both increased linearly with body size at a certain amount of diet. The retention phosphorus (RP) in fish of G1 was lower than G2. The relationship between retention phosphorus and body size was positive and stronger in G2. Significant difference in faecal phosphorus (FP) was found between G1 and G2. Body size significantly impacted the excretion phosphorus (EP) in G1 but G2. The loss of intake phosphorus in G1 was 10.83-20.27 mg per g fish weight gain, higher than that in G2 for 6.63-9.56. Of the phosphorus, about 10% was allocated into growth, 50% in faeces, and the rest lost in excretion. The main part of phosphorus was lost in faeces but excretion. The phosphorus budget of the fish could be described as 100IP = 7.40RP + 47.39FP + 36.63EP (Diet 1) or 100IP = 11.93RP + 56.64FP + 21.76EP (Diet 2).

  3. Dietary phosphorus and kidney disease.

    PubMed

    Uribarri, Jaime

    2013-10-01

    High serum phosphate is linked to poor health outcome and mortality in chronic kidney disease (CKD) patients before or after the initiation of dialysis. Therefore, maintenance of normal serum phosphate levels is a major concern in the clinical care of this population with dietary phosphorus restriction and/or use of oral phosphate binders considered to be the best corrective care. This review discusses (1) evidence for an association between serum phosphate levels and bone and cardiovascular disease (CVD) in CKD patients as well as progression of kidney disease itself; (2) the relationship between serum phosphate and dietary phosphorus intake; and (3) implications from these data for future research. Increasing our understanding of the relationship between altered phosphorus metabolism and disease in CKD patients may clarify the potential role of excess dietary phosphorus as a risk factor for disease in the general population.

  4. Black Phosphorus Optoelectronics and Electronics

    NASA Astrophysics Data System (ADS)

    Xia, Fengnian

    Black phosphorus recently emerged as a promising new 2D material due to its widely tunable and direct bandgap, high carrier mobility and remarkable in-plane anisotropic electrical, optical and phonon properties. It serendipitously bridges the zero-gap graphene and the relatively large-bandgap transition metal dichalcogenides such as molybdenum disulfide (MoS2) . In this talk, I will first cover the basic properties of few-layer and thin-film black phosphorus, followed by a discussion of recent observation of highly anisotropic robust excitons in monolayer black phosphorus. Finally I will present a few potential applications of black phosphorus such as radio-frequency transistors and wideband photodetectors. We acknowledge support from the Office of Naval Research, the Air Force Office of Scientific Research, the National Science Foundation and Yale University.

  5. Effects of phase-feeding dietary phosphorus on survival, growth, and processing characteristics of rainbow trout Oncorhynchus mykiss

    USGS Publications Warehouse

    Lellis, W.A.; Barrows, F.T.; Hardy, R.W.

    2004-01-01

    A factorial experiment involving eight diets and three feeding periods was conducted to determine the minimal level of dietary phosphorus required to maintain survival, growth, and processing characteristics of post-juvenile rainbow trout. Trout were reared to an average size of 200, 300, or 400 g using a commercial feed (1.20% P), then allotted by triplicate groups of nine fish to one of seven experimental diets containing logarithmic increments of dietary phosphorus (0.15%%, 0.21%, 0.30%, 0.42%, 0.60%, 0.85%, and 1.20% P) or a commercial trout feed (1.20% P). At an average weight of 550 g, fish were transported to a commercial processing plant, mechanically filleted, and evaluated for quality. Fish survival and weight gain increased quadratically with increased dietary phosphorus for fish started on treatment at 200 and 300 g, but were similar among all fish started at 400 g. Phosphorus retention decreased with increasing dietary phosphorus level, from approximately 88% in groups fed diets containing 0.21% phosphorus to between 23% and 32% in groups fed diets containing 0.85% phosphorus. Calculated phosphorus losses increased as dietary phosphorus levels increased, from a low of approximately 0.4 g phosphorus kg-1 fish weight gain to between 9.5 and 13 g phosphorus kg-1 fish weight gain at the highest dietary phosphorus level. Dietary phosphorus did not affect carcass moisture, protein, lipid, or ash, but carcass phosphorus increased with increased dietary phosphorus among fish started on treatment at 200 and 300 g. There were no differences among any treatment group in carcass dressing or finishing percentage, or visual or textural appeal. The results indicate that available phosphorus levels can be reduced in rainbow trout diets to 0.60% at 200 g, to 0.30% at 300 g, or to 0.15% at 400 g live weight without loss in production or product quality in fish harvested at 550 g. Using these phase-feeding strategies would reduce the amount of phosphorus fed to the fish

  6. Reexamining the Phosphorus-Protein Dilemma: Does Phosphorus Restriction Compromise Protein Status?

    PubMed

    St-Jules, David E; Woolf, Kathleen; Pompeii, Mary Lou; Kalantar-Zadeh, Kamyar; Sevick, Mary Ann

    2016-05-01

    Dietary phosphorus restriction is recommended to help control hyperphosphatemia in hemodialysis patients, but many high-phosphorus foods are important sources of protein. In this review, we examine whether restricting dietary phosphorus compromises protein status in hemodialysis patients. Although dietary phosphorus and protein are highly correlated, phosphorus intakes can range up to 600 mg/day for a given energy and protein intake level. Furthermore, the collinearity of phosphorus and protein may be biased because the phosphorus burden of food depends on: (1) the presence of phosphate additives, (2) food preparation method, and (3) bioavailability of phosphorus, which are often unaccounted for in nutrition assessments. Ultimately, we argue that clinically relevant reductions in phosphorus intake can be made without limiting protein intake by avoiding phosphate additives in processed foods, using wet cooking methods such as boiling, and if needed, substituting high-phosphorus foods for nutritionally equivalent foods that are lower in bioavailable phosphorus.

  7. A Substance Flow Model for Global Phosphorus

    NASA Astrophysics Data System (ADS)

    Vaccari, D. A.

    2015-12-01

    A system-based substance flow model (SFM) for phosphorus is developed based on the global phosphorus substance flow analysis (SFA) of Cordell et al (2009). The model is based strictly on mass balance considerations. It predicts the sensitivity of phosphorus consumption to various interventions intended to conserve reserves, as well as interactions among these efforts, allowing a comparison of their impacts on phosphorus demand. The interventions include control of phosphorus losses from soil erosion, food production and food waste, or phosphorus recycling such as from animal manure or human waste.

  8. 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

  9. 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

  10. III. Quantitative aspects of phosphorus excretion in ruminants.

    PubMed

    Bravo, David; Sauvant, Daniel; Bogaert, Catherine; Meschy, François

    2003-01-01

    Ruminant phosphorus excretion and metabolism were studied through a database. Faecal endogenous phosphorus is the main pathway of phosphorus excretion and averages 0.85 of total faecal phosphorus. The remaining 0.15 is unabsorbed dietary phosphorus. Faecal endogenous phosphorus is mainly unabsorbed phosphorus, with saliva being the major source, and is correlated to factors influencing saliva secretion (DM intake, physical dietary characteristics and dietary phosphorus content). Another source of faecal endogenous phosphorus is rumen microbial phosphorus that escaped solubilisation during post-rumen digestion. All factors stimulating microbial growth would increase phosphorus uptake by the rumen microbes and consequently the faecal endogenous phosphorus. Understanding the determinants of faecal endogenous phosphorus flow will help to precise the determination of net phosphorus requirements for maintenance. The role of plasma phosphorus in urinary phosphorus loss is discussed.

  11. 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.

  12. 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…

  13. Edge phonons in black phosphorus

    NASA Astrophysics Data System (ADS)

    Ribeiro, H. B.; Villegas, C. E. P.; Bahamon, D. A.; Muraca, D.; Castro Neto, A. H.; de Souza, E. A. T.; Rocha, A. R.; Pimenta, M. A.; de Matos, C. J. S.

    2016-07-01

    Black phosphorus has recently emerged as a new layered crystal that, due to its peculiar and anisotropic crystalline and electronic band structures, may have important applications in electronics, optoelectronics and photonics. Despite the fact that the edges of layered crystals host a range of singular properties whose characterization and exploitation are of utmost importance for device development, the edges of black phosphorus remain poorly characterized. In this work, the atomic structure and behaviour of phonons near different black phosphorus edges are experimentally and theoretically studied using Raman spectroscopy and density functional theory calculations. Polarized Raman results show the appearance of new modes at the edges of the sample, and their spectra depend on the atomic structure of the edges (zigzag or armchair). Theoretical simulations confirm that the new modes are due to edge phonon states that are forbidden in the bulk, and originated from the lattice termination rearrangements.

  14. Edge phonons in black phosphorus.

    PubMed

    Ribeiro, H B; Villegas, C E P; Bahamon, D A; Muraca, D; Castro Neto, A H; de Souza, E A T; Rocha, A R; Pimenta, M A; de Matos, C J S

    2016-01-01

    Black phosphorus has recently emerged as a new layered crystal that, due to its peculiar and anisotropic crystalline and electronic band structures, may have important applications in electronics, optoelectronics and photonics. Despite the fact that the edges of layered crystals host a range of singular properties whose characterization and exploitation are of utmost importance for device development, the edges of black phosphorus remain poorly characterized. In this work, the atomic structure and behaviour of phonons near different black phosphorus edges are experimentally and theoretically studied using Raman spectroscopy and density functional theory calculations. Polarized Raman results show the appearance of new modes at the edges of the sample, and their spectra depend on the atomic structure of the edges (zigzag or armchair). Theoretical simulations confirm that the new modes are due to edge phonon states that are forbidden in the bulk, and originated from the lattice termination rearrangements. PMID:27412813

  15. Edge phonons in black phosphorus

    PubMed Central

    Ribeiro, H. B.; Villegas, C. E. P.; Bahamon, D. A.; Muraca, D.; Castro Neto, A. H.; de Souza, E. A. T.; Rocha, A. R.; Pimenta, M. A.; de Matos, C. J. S.

    2016-01-01

    Black phosphorus has recently emerged as a new layered crystal that, due to its peculiar and anisotropic crystalline and electronic band structures, may have important applications in electronics, optoelectronics and photonics. Despite the fact that the edges of layered crystals host a range of singular properties whose characterization and exploitation are of utmost importance for device development, the edges of black phosphorus remain poorly characterized. In this work, the atomic structure and behaviour of phonons near different black phosphorus edges are experimentally and theoretically studied using Raman spectroscopy and density functional theory calculations. Polarized Raman results show the appearance of new modes at the edges of the sample, and their spectra depend on the atomic structure of the edges (zigzag or armchair). Theoretical simulations confirm that the new modes are due to edge phonon states that are forbidden in the bulk, and originated from the lattice termination rearrangements. PMID:27412813

  16. 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

  17. Black phosphorus nonvolatile transistor memory.

    PubMed

    Lee, Dain; Choi, Yongsuk; Hwang, Euyheon; Kang, Moon Sung; Lee, Seungwoo; Cho, Jeong Ho

    2016-04-28

    We demonstrated nanofloating gate transistor memory devices (NFGTMs) using mechanically-exfoliated few-layered black phosphorus (BP) channels and gold nanoparticle (AuNPs) charge trapping layers. The resulting BP-NFGTMs exhibited excellent memory performances, including the five-level data storage, large memory window (58.2 V), stable retention (10(4) s), and cyclic endurance (1000 cycles). PMID:27074903

  18. 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.

  19. 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...

  20. Natural phosphorus sources for the Pacific Northwest

    USGS Publications Warehouse

    Johnson, Hank

    2011-01-01

    Phosphorus is a naturally occurring element found in all rocks; the amount varies by the type of rock. The amount of phosphorus in sediments is expected to be correlated with the amount of phosphorus in the parent rocks. Streambed sediment collected by the National Uranium Resource Evaluation (NURE) Program were used to estimate the variation of phosphorus across the Pacific Northwest. This file provides an estimate of the mean concentration of phosphorus in soils for each incremental catchment of the USGS Pacific Northwest SPARROW model.

  1. Few-layer black phosphorus nanoparticles.

    PubMed

    Sofer, Zdenek; Bouša, Daniel; Luxa, Jan; Mazanek, Vlastimil; Pumera, Martin

    2016-01-28

    Herein, black phosphorus quantum dots and nanoparticles of a few layer thickness were prepared and characterized using STEM, AFM, dynamic light scattering, X-ray photoelectron spectroscopy, X-ray diffraction, Raman spectroscopy and photoluminescence. Impact electrochemistry of the induvidual black phosphorus nanoparticles allows their size determination. The centrifugation of colloidal black phosphorus nanoparticles allowed separation of quantum dots with sizes up to 15 nm. These black phosphorus nanoparticles exhibit a large band gap and are expected to find a wide range of applications from semiconductors to biomolecule tags. The use of black phosphorus nanoparticles for vapour sensing was successfully demonstrated.

  2. 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 α 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.

  3. Global warming and the phosphorus cycle

    SciTech Connect

    Tarasova, N.P.; Smetannikov, Y.V.; Balitsky, V.Y. )

    1994-09-01

    Greenhouse-induced climate change seriously influences the phosphorus cycle. In this paper the authors have analyzed how environmental conditions cause an increase or a decrease in the phosphorus content of the soil. Phosphorus production in South Kazakhstan without strict control for fulfilling environment-protection measures may lead to the chemical erosion of soils, i.e., disturb the balance of soluble and insoluble, as well as organic and inorganic, forms of phosphorus. Phosphorus accumulation in the soil can be promoted by heavy metals. The authors have constructed a general dynamic system for phosphorus flows in the soil. The results of 7-years monitoring of the soils in the region of South Kazakhstan are discussed and compared with the dynamic system. The role of chemical elements promoting phosphorus accumulation in the soil is further analyzed.

  4. 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

  5. Aldehyde insertion into a platinum hydride and subsequent nucleophilic attack of the alkoxide at phosphorus: Platinum-alkoxide/phosphorus-aryl metathesis

    SciTech Connect

    van Leeuwen, P.W.N.M.; Roobeek, C.F. ); Orpen, A.G. )

    1990-08-01

    Pt(Ph{sub 2}PO)(Ph{sub 2}POH){sub 2}H (1) was treated with o-(diphenylphosphino)benzaldehyde to give a cyclic platinum alkoxide (2). The latter rearranges to the new product 3 (Scheme I), containing 1-phenyl-3H-2,1-benzoxaphosphole and a phenyl group coordinated to platinum, via a nucleophilic attack at the coordinated phosphorus center by the alkoxy group, followed by a shift of a phenyl group from phosphorus to platinum. The crystal structure of 3 has been determined.

  6. Black phosphorus nonvolatile transistor memory

    NASA Astrophysics Data System (ADS)

    Lee, Dain; Choi, Yongsuk; Hwang, Euyheon; Kang, Moon Sung; Lee, Seungwoo; Cho, Jeong Ho

    2016-04-01

    We demonstrated nanofloating gate transistor memory devices (NFGTMs) using mechanically-exfoliated few-layered black phosphorus (BP) channels and gold nanoparticle (AuNPs) charge trapping layers. The resulting BP-NFGTMs exhibited excellent memory performances, including the five-level data storage, large memory window (58.2 V), stable retention (104 s), and cyclic endurance (1000 cycles).We demonstrated nanofloating gate transistor memory devices (NFGTMs) using mechanically-exfoliated few-layered black phosphorus (BP) channels and gold nanoparticle (AuNPs) charge trapping layers. The resulting BP-NFGTMs exhibited excellent memory performances, including the five-level data storage, large memory window (58.2 V), stable retention (104 s), and cyclic endurance (1000 cycles). Electronic supplementary information (ESI) available. See DOI: 10.1039/c6nr02078j

  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. Ultra-Long Crystalline Red Phosphorus Nanowires from Amorphous Red Phosphorus Thin Films.

    PubMed

    Smith, Joshua B; Hagaman, Daniel; DiGuiseppi, David; Schweitzer-Stenner, Reinhard; Ji, Hai-Feng

    2016-09-19

    Heating red phosphorus in sealed ampoules in the presence of a Sn/SnI4 catalyst mixture has provided bulk black phosphorus at much lower pressures than those required for allotropic conversion by anvil cells. Herein we report the growth of ultra-long 1D red phosphorus nanowires (>1 mm) selectively onto a wafer substrate from red phosphorus powder and a thin film of red phosphorus in the present of a Sn/SnI4 catalyst. Raman spectra and X-ray diffraction characterization suggested the formation of crystalline red phosphorus nanowires. FET devices constructed with the red phosphorus nanowires displayed a typical I-V curve similar to that of black phosphorus and a similar mobility reaching 300 cm(2)  V(-1)  s with an Ion /Ioff ratio approaching 10(2) . A significant response to infrared light was observed from the FET device. PMID:27553637

  9. Ultra-Long Crystalline Red Phosphorus Nanowires from Amorphous Red Phosphorus Thin Films.

    PubMed

    Smith, Joshua B; Hagaman, Daniel; DiGuiseppi, David; Schweitzer-Stenner, Reinhard; Ji, Hai-Feng

    2016-09-19

    Heating red phosphorus in sealed ampoules in the presence of a Sn/SnI4 catalyst mixture has provided bulk black phosphorus at much lower pressures than those required for allotropic conversion by anvil cells. Herein we report the growth of ultra-long 1D red phosphorus nanowires (>1 mm) selectively onto a wafer substrate from red phosphorus powder and a thin film of red phosphorus in the present of a Sn/SnI4 catalyst. Raman spectra and X-ray diffraction characterization suggested the formation of crystalline red phosphorus nanowires. FET devices constructed with the red phosphorus nanowires displayed a typical I-V curve similar to that of black phosphorus and a similar mobility reaching 300 cm(2)  V(-1)  s with an Ion /Ioff ratio approaching 10(2) . A significant response to infrared light was observed from the FET device.

  10. 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.

  11. Phosphorus and Nutrition in Chronic Kidney Disease

    PubMed Central

    González-Parra, Emilio; Gracia-Iguacel, Carolina; Egido, Jesús; Ortiz, Alberto

    2012-01-01

    Patients with renal impairment progressively lose the ability to excrete phosphorus. Decreased glomerular filtration of phosphorus is initially compensated by decreased tubular reabsorption, regulated by PTH and FGF23, maintaining normal serum phosphorus concentrations. There is a close relationship between protein and phosphorus intake. In chronic renal disease, a low dietary protein content slows the progression of kidney disease, especially in patients with proteinuria and decreases the supply of phosphorus, which has been directly related with progression of kidney disease and with patient survival. However, not all animal proteins and vegetables have the same proportion of phosphorus in their composition. Adequate labeling of food requires showing the phosphorus-to-protein ratio. The diet in patients with advanced-stage CKD has been controversial, because a diet with too low protein content can favor malnutrition and increase morbidity and mortality. Phosphorus binders lower serum phosphorus and also FGF23 levels, without decreasing diet protein content. But the interaction between intestinal dysbacteriosis in dialysis patients, phosphate binder efficacy, and patient tolerance to the binder could reduce their efficiency. PMID:22701173

  12. Impact of phosphorus control measures on in-river phosphorus retention associated with point source pollution

    NASA Astrophysics Data System (ADS)

    Demars, B. O. L.; Harper, D. M.; Pitt, J.-A.; Slaughter, R.

    2005-01-01

    In-river phosphorus retention alters the quantity and timings of phosphorus delivery to downstream aquatic systems. Many intensive studies of in-river phosphorus retention have been carried out but generally on a short time scale (2-4 years). In this paper, monthly water quality data, collected by the Environment Agency of England and Wales over 12 years (1990-2001), were used to model daily phosphorus fluxes and monthly in-river phosphorus retention in the lowland calcareous River Wensum, Norfolk, UK. The effectiveness of phosphorus stripping at two major sewage treatment works was quantified over different hydrological conditions. The model explained 78% and 88% of the observed variance before and after phosphorus control, respectively. During relatively dry years, there was no net export of phosphorus from the catchment. High retention of phosphorus occurred, particularly during the summer months, which was not compensated for, by subsequent higher flow events. The critical discharge (Q) above which net remobilisation would occur, was only reached during few, high flow events Q25-Q13. Phosphorus removal from the effluent at two major STWs (Sewage Treatment Works) reduced the phosphorus catchment mass balance variability by 20-24% under the Q99-Q1. range of flow conditions. Although the absorbing capacity of the catchment against human impact was remarkable, further phosphorus remedial strategies will be necessary to prevent downstream risks of eutrophication occuring independently of the unpredictable variability in weather conditions.

  13. 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...

  14. Optimization of a full-scale Unitank wastewater treatment plant for biological phosphorus removal.

    PubMed

    Zhou, Zhen; Xing, Can; Wu, Zhichao; Tong, Fei; Wang, Junru

    2014-01-01

    The Unitank process combines the advantages of traditional continuous-flow activated sludge processes and sequencing batch reactors, and has been extensively employed in many wastewater treatment plants (WWTPs) in China. Biological phosphorus removal (BPR) of a full-scale Unitank WWTP was optimized by increasing anaerobic time from 80 to 120 min in an operation cycle of 360 min and reducing solid retention time (SRT) from 21.3 to 13.1 d. The BPR efficiency of the full-scale Unitank system increased from 63.8% (SRT of 21.3 d) to 83.2% for a SRT of 13.1 d. When the anaerobic time increased from 80 to 120 min, the net anaerobic phosphorus release amount increased from 0.25 to 1.06 mg L(-1), and sludge phosphorus content rose from 13.8 to 15.0 mgP x (gSS)(-1). During half an operation cycle, the average specific phosphorus release rate increased from 0.097mgP x (gVSS x h)(-1) in 0-40 min to 0.825 mgP x (gVSS x h)(-1) in 40-60 min. Reducing SRT and increasing anaerobic time account for 84.6% and 15.4% in the total increment of phosphorus removal of 1.15 mgL(-1).

  15. Optimization of a full-scale Unitank wastewater treatment plant for biological phosphorus removal.

    PubMed

    Zhou, Zhen; Xing, Can; Wu, Zhichao; Tong, Fei; Wang, Junru

    2014-01-01

    The Unitank process combines the advantages of traditional continuous-flow activated sludge processes and sequencing batch reactors, and has been extensively employed in many wastewater treatment plants (WWTPs) in China. Biological phosphorus removal (BPR) of a full-scale Unitank WWTP was optimized by increasing anaerobic time from 80 to 120 min in an operation cycle of 360 min and reducing solid retention time (SRT) from 21.3 to 13.1 d. The BPR efficiency of the full-scale Unitank system increased from 63.8% (SRT of 21.3 d) to 83.2% for a SRT of 13.1 d. When the anaerobic time increased from 80 to 120 min, the net anaerobic phosphorus release amount increased from 0.25 to 1.06 mg L(-1), and sludge phosphorus content rose from 13.8 to 15.0 mgP x (gSS)(-1). During half an operation cycle, the average specific phosphorus release rate increased from 0.097mgP x (gVSS x h)(-1) in 0-40 min to 0.825 mgP x (gVSS x h)(-1) in 40-60 min. Reducing SRT and increasing anaerobic time account for 84.6% and 15.4% in the total increment of phosphorus removal of 1.15 mgL(-1). PMID:24645458

  16. Trapping phosphorus in runoff with a phosphorus removal structure.

    PubMed

    Penn, Chad J; McGrath, Joshua M; Rounds, Elliott; Fox, Garey; Heeren, Derek

    2012-01-01

    Reduction of phosphorus (P) inputs to surface waters may decrease eutrophication. Some researchers have proposed filtering dissolved P in runoff with P-sorptive byproducts in structures placed in hydrologically active areas with high soil P concentrations. The objectives of this study were to construct and monitor a P removal structure in a suburban watershed and test the ability of empirically developed flow-through equations to predict structure performance. Steel slag was used as the P sorption material in the P removal structure. Water samples were collected before and after the structure using automatic samples and analyzed for total dissolved P. During the first 5 mo of structure operation, 25% of all dissolved P was removed from rainfall and irrigation events. Phosphorus was removed more efficiently during low flow rate irrigation events with a high retention time than during high flow rate rainfall events with a low retention time. The six largest flow events occurred during storm flow and accounted for 75% of the P entering the structure and 54% of the P removed by the structure. Flow-through equations developed for predicting structure performance produced reasonable estimates of structure "lifetime" (16.8 mo). However, the equations overpredicted cumulative P removal. This was likely due to differences in pH, total Ca and Fe, and alkalinity between the slag used in the structure and the slag used for model development. This suggests the need for an overall model that can predict structure performance based on individual material properties.

  17. Plant growth, phosphorus nutrition, and root morphological responses to arbuscular mycorrhizas, phosphorus fertilization, and intraspecific density.

    PubMed

    Schroeder, M S; Janos, D P

    2005-05-01

    We examined the effects of arbuscular mycorrhizas (AM), phosphorus fertilization, intraspecific density, and their interaction, on the growth, phosphorus uptake, and root morphology of three facultative mycotrophic crops (Capsicum annuum, Zea mays, and Cucurbita pepo). Plants were grown in pots with or without AM at three densities and four phosphorus availabilities for 10 weeks. AM colonization, plant weight, and shoot phosphorus concentration were measured at harvest. Root morphology was assessed for C. annuum and Z. mays. Phosphorus fertilization reduced but did not eliminate AM colonization of all species. AM, phosphorus, and density interacted significantly to modify growth of C. annuum and C. pepo such that increased density and phosphorus diminished beneficial effects of AM. Increased density reduced positive effects of AM on C. annuum and C. pepo shoot phosphorus concentrations. AM altered both Z. mays and C. annuum root morphology in ways that complemented potential phosphorus uptake by mycorrhizas, but increased density and phosphorus diminished these effects. We infer that increased density predominantly influenced plant responses by affecting whether or not carbon (photosynthate) or phosphorus limited plant growth. By exacerbating carbon limitation, high density reduced the benefit/cost ratio of mycorrhizas and minimized their effects.

  18. Phosphorus removal in an enhanced biological phosphorus removal process: roles of extracellular polymeric substances.

    PubMed

    Zhang, Hai-Ling; Fang, Wei; Wang, Yong-Peng; Sheng, Guo-Ping; Zeng, Raymond J; Li, Wen-Wei; Yu, Han-Qing

    2013-10-15

    Phosphorus-accumulating organisms are considered to be the key microorganisms in the enhanced biological phosphorus removal (EBPR) process. A large amount of phosphorus is found in the extracellular polymeric substances (EPS) matrix of these microorganisms. However, the roles of EPS in phosphorus removal have not been fully understood. In this study, the phosphorus in the EBPR sludge was fractionated and further analyzed using quantitative (31)P nuclear magnetic resonance spectroscopy. The amounts and forms of phosphorus in EPS as well as their changes in an anaerobic-aerobic process were also investigated. EPS could act as a reservoir for phosphorus in the anaerobic-aerobic process. About 5-9% of phosphorus in sludge was reserved in the EPS at the end of the aerobic phase and might further contribute to the phosphorus removal. The chain length of the intracellular long-chain polyphosphate (polyP) decreased in the anaerobic phase and then recovered under aerobic conditions. However, the polyP in the EPS had a much shorter chain length than the intracellular polyP in the whole cycle. The migration and transformation of various forms of phosphorus among microbial cells, EPS, and bulk liquid were also explored. On the basis of these results, a model with a consideration of the roles of EPS was proposed, which is beneficial to elucidate the mechanism of phosphorus removal in the EBPR system.

  19. Sedimentary phosphorus cycling and a phosphorus mass balance for the Green Bay (Lake Michigan) ecosystem

    USGS Publications Warehouse

    Klump, J.V.; Edgington, D. N.; Sager, P.E.; Robertson, D.M.

    2011-01-01

    The tributaries of Green Bay have long been recognized as major sources of phosphorus in the Lake Michigan basin. The status of Green Bay as a sink or source of phosphorus for Lake Michigan proper has been less well defined. The bay receives nearly 70% of its annual load of phosphorus ( 700 metric tons (t) · year-1) from a single source: the Fox River. Most of this phosphorus is deposited in sediments accumulating at rates that reach 160 mg · cm-2 · year-1 with an average of 20 mg · cm-2 · year-1. The phosphorus content of these sediments varies from <5 to >70 µmol · g-1. Deposition is highly focused, with ~70% of the total sediment accumulation and at least 80% of the phosphorus burial occurring within 20% of the surface area of the bay. Diagenetic and stoichiometric models of phosphorus cycling imply that >80% of the phosphorus deposited is permanently buried. External phosphorus loading to the bay is combined with sediment fluxes of phophorus to arrive at a simple phosphorus budget. Green Bay acts as an efficient nutrient trap, with the sediments retaining an estimated 70-90% of the external phosphorus inputs before flowing into Lake Michigan.

  20. Sedimentary phosphorus cycling and a phosphorus mass balance for the Green Bay (Lake Michigan) ecosystem

    USGS Publications Warehouse

    Val, Klump J.; Edgington, D.N.; Sager, P.E.; Robertson, D.M.

    1997-01-01

    The tributaries of Green Bay have long been recognized as major sources of phosphorus in the Lake Michigan basin. The status of Green Bay as a sink or source of phosphorus for Lake Michigan proper has been less well defined. The bay receives nearly 70% of its annual load of phosphorus (700 metric tons (t)??year-1) from a single source: the Fox River. Most of this phosphorus is deposited in sediments accumulating at rates that reach 160 mg??cm-2??year-1 with an average of 20 mg??cm-2 year-1. The phosphorus content of these sediments varies from 70 ??mol??g-1. Deposition is highly focused, with ???0% of the total sediment accumulation and at least 80% of the phosphorus burial occurring within 20% of the surface area of the bay. Diagenetic and stoichiometric models of phosphorus cycling imply that >80% of the phosphorus deposited is permanently buried. External phosphorus loading to the bay is combined with sediment fluxes of phophorus to arrive at a simple phosphorus budget. Green Bay acts as an efficient nutrient trap, with the sediments retaining an estimated 70-90% of the external phosphorus inputs before flowing into Lake Michigan.

  1. 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.

  2. Removal of phosphorus by peritoneal dialysis.

    PubMed

    Delmez, J A

    1993-01-01

    Substantial evidence exists that peritoneal dialysis, as currently practiced, cannot alone remove adequate amounts of phosphorus in well-nourished patients. Current efforts should address the possibility of developing improved nontoxic oral phosphorus binders and/or different compositions of dialysate fluid. PMID:8399639

  3. Sustainable use of phosphorus: a finite resource.

    PubMed

    Scholz, Roland W; Ulrich, Andrea E; Eilittä, Marjatta; Roy, Amit

    2013-09-01

    Phosphorus is an essential element of life and of the modern agricultural system. Today, science, policy, agro-industry and other stakeholder groups are increasingly concerned about the sustainable use of this resource, given the dissipative nature of phosphorus and difficulties in assessing, evaluating, and coping with phosphorus pollution in aquatic and terrestrial systems. We argue that predictions about a forthcoming peak, followed by a quick reduction (i.e., physical phosphate rock scarcity) are unreasoned and stress that access to phosphorus (economic scarcity) is already, and may increasingly become critical, in particular for smallholders farmers in different parts of the world. The paper elaborates on the design, development, goals and cutting-edge contributions of a global transdisciplinary process (i.e. mutual learning between science and society including multiple stakeholders) on the understanding of potential contributions and risks related to the current mode of using phosphorus on multiple scales (Global TraPs). While taking a global and comprehensive view on the whole phosphorus-supply chain, Global TraPs organizes and integrates multiple transdisciplinary case studies to better answer questions which inform sustainable future phosphorus use. Its major goals are to contribute to four issues central to sustainable resource management: i) long-term management of biogeochemical cycles, in particular the challenge of closing the phosphorus cycle, ii) achieving food security, iii) avoiding environmental pollution and iv) sustainability learning on a global level by transdisciplinary processes.

  4. 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...

  5. The phosphorus speciations in the sediments up- and down-stream of cascade dams along the middle Lancang River.

    PubMed

    Liu, Qi; Liu, Shiliang; Zhao, Haidi; Deng, Li; Wang, Cong; Zhao, Qinghe; Dong, Shikui

    2015-02-01

    We detected the longitudinal variability of phosphorus speciations and its relation to metals and grain size distribution of sediments in three cascade canyon reservoirs (Xiaowan, Manwan and Dachaoshan) along Lancang River, China. Five phosphorus speciations including loosely bound P (ex-P), reductant soluble P (BD-P), metal oxide-bound P (NaOH-P) calcium-bound P (HCl-P) and residual-P were extracted and quantified. Results showed that in Manwan Reservoir HCl-P accounted for the largest part of total phosphorus (TP) (49.69%), while in Xiaowan and Dachaoshan reservoirs, NaOH-P was the most abundant speciation which accounted for 57.21% and 55.19% of total phosphorus respectively. Higher contents of bio-available phosphorus in Xiaowan and Dachaoshan reservoirs suggested a high rate of P releasing from sediments. Results also showed ex-P and HCl-P had positive correlation with Ca. Total phosphorus was positively correlated with Fe. The silt/clay contents of the sediments had close relationship with ex-P (r=0.413, p<0.05), NaOH-P (r=0.428, p<0.05) and BAP (r=0.458, p<0.05). The concentration of Ca, Mn and silt/clay speciation in the sediments explained 40%, 10% and 4% of the spatial variation of phosphorus speciations, respectively.

  6. The phosphorus speciations in the sediments up- and down-stream of cascade dams along the middle Lancang River.

    PubMed

    Liu, Qi; Liu, Shiliang; Zhao, Haidi; Deng, Li; Wang, Cong; Zhao, Qinghe; Dong, Shikui

    2015-02-01

    We detected the longitudinal variability of phosphorus speciations and its relation to metals and grain size distribution of sediments in three cascade canyon reservoirs (Xiaowan, Manwan and Dachaoshan) along Lancang River, China. Five phosphorus speciations including loosely bound P (ex-P), reductant soluble P (BD-P), metal oxide-bound P (NaOH-P) calcium-bound P (HCl-P) and residual-P were extracted and quantified. Results showed that in Manwan Reservoir HCl-P accounted for the largest part of total phosphorus (TP) (49.69%), while in Xiaowan and Dachaoshan reservoirs, NaOH-P was the most abundant speciation which accounted for 57.21% and 55.19% of total phosphorus respectively. Higher contents of bio-available phosphorus in Xiaowan and Dachaoshan reservoirs suggested a high rate of P releasing from sediments. Results also showed ex-P and HCl-P had positive correlation with Ca. Total phosphorus was positively correlated with Fe. The silt/clay contents of the sediments had close relationship with ex-P (r=0.413, p<0.05), NaOH-P (r=0.428, p<0.05) and BAP (r=0.458, p<0.05). The concentration of Ca, Mn and silt/clay speciation in the sediments explained 40%, 10% and 4% of the spatial variation of phosphorus speciations, respectively. PMID:25462310

  7. 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

    -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

  8. 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.

  9. Impact of phosphorus control measures on in-river phosphorus retention associated with point source pollution

    NASA Astrophysics Data System (ADS)

    Demars, B. O. L.; Harper, D. M.; Pitt, J.-A.; Slaughter, R.

    2005-06-01

    In-river phosphorus retention alters the quantity and timings of phosphorus delivery to downstream aquatic systems. Many intensive studies of in-river phosphorus retention have been carried out but generally on a short time scale (2-4 years). In this paper, monthly water quality data, collected by the Environment Agency of England and Wales over 12 years (1990-2001), were used to model daily phosphorus fluxes and monthly in-river phosphorus retention in the lowland calcareous River Wensum, Norfolk, UK. The calibrated model explained 79% and 89% of the observed variance before and after phosphorus control, respectively. A split test revealed that predicted TP loads were in good agreement with observed TP loads (r2=0.85), although TP loads were underestimated under high flow conditions. During relatively dry years, there was no net export of phosphorus from the catchment. High retention of phosphorus occurred, particularly during the summer months, which was not compensated for, by subsequent higher flow events. This was despite a relatively modest critical discharge (Q) above which net remobilisation occur. Phosphorus removal from the effluent at two major STWs (Sewage Treatment Works) reduced phosphorus retention but not the remobilisation. This may indicate that the presence of impoundments and weirs, or overbank flows may have more control on the phosphorus dynamics under high flow conditions. Further phosphorus remedial strategies will be necessary to prevent downstream risks of eutrophication occurring independently of the unpredictable variability in weather conditions. More research is also needed to quantify the impact of the weir and overbank flows on phosphorus dynamics.

  10. The effect of nanotopography on calcium and phosphorus deposition on metallic materials in vitro.

    PubMed

    Ward, Brian C; Webster, Thomas Jay

    2006-06-01

    To date, long-term functions of osteoblasts leading to calcium and phosphorus mineral deposition on nanometals have not been determined. Nanometals are metals with constituent metal particles and/or surface features less than 100 nm in at least one dimension. For this reason, the objective of this in vitro study was to determine the amount of calcium and phosphorus mineral formation on microphase compared to nanophase Ti, Ti6Al4V, and CoCrMo cultured with and without osteoblasts (bone-forming cells). The results of this study provided the first evidence of significantly greater calcium and phosphorus deposition by osteoblasts and precipitation from culture media without osteoblasts on nanophase compared to respective microphase Ti6Al4V and CoCrMo after 21 days; the greatest calcium and phosphorus mineral deposition occurred on nanophase CoCrMo while the greatest calcium and phosphorus mineral precipitation without osteoblasts occurred on nanophase Ti6Al4V. No differences were found for any type of Ti: wrought, microphase, or nanophase. Moreover, increased calcium and phosphorus mineral content correlated to greater amounts of underlying aluminum content on Ti6Al4V surfaces. Since, compared to microphase Ti6Al4V, nanophase Ti6Al4V contained a higher amount of aluminum at the surface (due to greater surface area), this may provide a reason for enhanced calcium and phosphorus mineral content on nanophase Ti6Al4V. Regardless of the mechanism, this study continues to support the further investigation of nanometals for improved orthopedic applications.

  11. Nitrogen and phosphorus budget in rewetted fens.

    PubMed

    Lenz, A; Wild, U

    2001-01-01

    A former dewatered fen was flooded for a multi-purpose landuse system including cattail production, fen protection, and water purification. These research plants with an area of 6 ha consist of three constructed surface-flow wetlands. The inflowing water is polluted by non-point sources due to intensive agriculture. The focus of this paper is the estimation of the potential of rewetted fens to reduce phosphorus and nitrogen. The dominating forms of nitrogen in the inflow are organic nitrogen and nitrate. The reduction rate is higher for nitrate than for organic nitrogen, although the nitrate reductions occur only during the summer season. If no nitrate is available for denitrification, there is a release of ammonia from the peat into the water. The main form of phosphorus in the in- and outflow is ortho-phosphate. In contrast to the values of nitrate, the concentrations of phosphorus are very regular with no significant seasonal pattern. When nitrate isn't available in the water any more, the release of phosphorus begins and the rewetted fens change from a sink for phosphorus to a source of it. Rewetted fens can be a sink for phosphorus and nitrogen with nitrate as the limiting factor. Only if denitrification can occur, can the release of ammonia and phosphorus from the peat layer be prevented.

  12. 49 CFR 173.188 - White or yellow phosphorus.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ...) Inner water-tight metal cans containing not over 0.5 kg (1 pound) of phosphorus with screw-top closures... 49 Transportation 2 2013-10-01 2013-10-01 false White or yellow phosphorus. 173.188 Section 173... Class 7 § 173.188 White or yellow phosphorus. Phosphorus, white or yellow, when offered...

  13. 49 CFR 173.188 - White or yellow phosphorus.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ...) Inner water-tight metal cans containing not over 0.5 kg (1 pound) of phosphorus with screw-top closures... 49 Transportation 2 2014-10-01 2014-10-01 false White or yellow phosphorus. 173.188 Section 173... Class 7 § 173.188 White or yellow phosphorus. Phosphorus, white or yellow, when offered...

  14. Efficient recovery of carbon, nitrogen, and phosphorus from waste activated sludge.

    PubMed

    Chen, Yinguang; Zheng, Xiong; Feng, Leiyu; Yang, Hong

    2013-01-01

    Carbon, nitrogen, and phosphorus need to be recovered to reduce the environmental impact of waste activated sludge (WAS). In this study the improved short-chain fatty acid (SCFA) production from WAS by the addition of kitchen waste to adjust the ratio of carbon to nitrogen (C/N), and the efficient recovery of nitrogen and phosphorus from the fermentation liquid were reported. Firstly, the optimum conditions for SCFA production were found to be pH 8, temperature 35 °C, C/N ratio 21 mg-C/1 mg-N, and fermentation time 6 d, using the response surface methodology. After alkaline fermentation, the struvite precipitation method was applied to efficiently and simultaneously recover the released ammonia and phosphorus from the fermentation liquid. Finally, the fermentation liquid was used as the additional carbon source for biological nitrogen and phosphorus removal. It was observed that, compared with acetic acid, the use of fermentation liquid as carbon source showed greater removal efficiencies of total nitrogen and total phosphorus.

  15. Black phosphorus for future devices

    NASA Astrophysics Data System (ADS)

    Meunier, Vincent

    Black phosphorus (or ``phosphorene'' at the monolayer limit) has attracted significant attention as an emerging 2D material due to its unique properties compared with well-explored graphene and transition metal dichalcogenides such as MoS2 and WSe2. In bulk form, this monoelemental layered structure is a highly anisotropic semiconductor with a bandgap of 0.3 eV which presents marked distinctions in optical and electronic properties depending on crystalline directions. In addition, black phosphorus possesses a high carrier mobility, making it promising for applications in high frequency electronics. A large number of characterization studies have been performed to understand the intrinsic properties of BP. Here I wil present a number of investigations where first-principles modelling was combined with scanning tunneling microscopy (STM), Raman spectroscopy, and transmission electron microscopy (TEM) to assist in the design of phosphorene-based devices. . I will provide an overview of these studies and position them in the context of the very active research devoted to this material. In particular, I will show how low-frequency Raman spectra provide a unique handle on the physics of multilayered systems and how BP's structural anisotropy weaves its way to its unusual polarization dependent Raman signature. Finally, I will show recent progress where nanopores, nanobridges, and nanogaps have been sculpted directly from a few-layer BP sample using a TEM, and indicate the potential use of these results on the creation of phosphorene-based nanoelectronics. I wil conclude this talk with a critical look at the issues of phosphorene stability under ambient conditions. Collaborators on this research include: Liangbo Liang, Bobby G. Sumpter, Alex Puretzky, Minghu Pan, (Oak Ridge National Laboratory), Marija Drndic (University of Pennsylvania), Mildred Dresselhaus, Xi-Ling, Shengxi Huang (Massachusetts Institute of Technology).

  16. Weak Localization in few layer Black Phosphorus

    NASA Astrophysics Data System (ADS)

    Gillgren, Nathaniel; Shi, Yanmeng; Espiritu, Timothy; Watanabe, Kenji; Taniguchi, Takahashi; Lau, Chun Ning (Jeanie)

    Few-layer black phosphorus has recently attracted interest from the scientific community due to its high mobility, tunable band gap, and large anisotropy. Recent experiments have demonstrated that black phosphorus provides a promising candidate to explore the physics of 2D semiconductors. In this study we explore the magnetotransport of few-layer black phosphorus-boron nitride hetereostructure devices at low magnetic fields. Weak localization is observed at low temperatures. We extract the dephasing length and measure its dependence on temperature, carrier density and electric field.

  17. Dietary and plasma phosphorus in hens with fatty liver syndrome.

    PubMed

    Miles, R D; Christmas, R B; Harms, R H

    1982-12-01

    Plasma inorganic phosphorus was determined in two experiments in hens that had fatty liver syndrome. In Experiment 1, plasma inorganic phosphorus was determined in twelve strains of hens all fed the same diet. Plasma inorganic phosphorus immediately following oviposition was elevated in all strains. The two strains in the first experiment with the highest as well as the two strains with the lowest plasma inorganic phosphorus were used in the second experiment. Each of the four strains were subdivided into three groups of 60 hens each and fed a practical layer diet containing either .30, .75, or 1.40% total phosphorus and 3.4% calcium. Significant differences were found in plasma inorganic phosphorus between strains fed the three dietary phosphorus levels. Results indicated that plasma inorganic phosphorus is related to dietary phosphorus in hens with an elevated plasma inorganic phosphorus level associated with fatty liver syndrome.

  18. Towards global phosphorus security: a systems framework for phosphorus recovery and reuse options.

    PubMed

    Cordell, D; Rosemarin, A; Schröder, J J; Smit, A L

    2011-08-01

    Human intervention in the global phosphorus cycle has mobilised nearly half a billion tonnes of the element from phosphate rock into the hydrosphere over the past half century. The resultant water pollution concerns have been the main driver for sustainable phosphorus use (including phosphorus recovery). However the emerging global challenge of phosphorus scarcity with serious implications for future food security, means phosphorus will also need to be recovered for productive reuse as a fertilizer in food production to replace increasingly scarce and more expensive phosphate rock. Through an integrated and systems framework, this paper examines the full spectrum of sustainable phosphorus recovery and reuse options (from small-scale low-cost to large-scale high-tech), facilitates integrated decision-making and identifies future opportunities and challenges for achieving global phosphorus security. Case studies are provided rather than focusing on a specific technology or process. There is no single solution to achieving a phosphorus-secure future: in addition to increasing phosphorus use efficiency, phosphorus will need to be recovered and reused from all current waste streams throughout the food production and consumption system (from human and animal excreta to food and crop wastes). There is a need for new sustainable policies, partnerships and strategic frameworks to develop renewable phosphorus fertilizer systems for farmers. Further research is also required to determine the most sustainable means in a given context for recovering phosphorus from waste streams and converting the final products into effective fertilizers, accounting for life cycle costs, resource and energy consumption, availability, farmer accessibility and pollution.

  19. Epitaxial Growth of Single Layer Blue Phosphorus: A New Phase of Two-Dimensional Phosphorus.

    PubMed

    Zhang, Jia Lin; Zhao, Songtao; Han, Cheng; Wang, Zhunzhun; Zhong, Shu; Sun, Shuo; Guo, Rui; Zhou, Xiong; Gu, Cheng Ding; Yuan, Kai Di; Li, Zhenyu; Chen, Wei

    2016-08-10

    Blue phosphorus, a previously unknown phase of phosphorus, has been recently predicted by theoretical calculations and shares its layered structure and high stability with black phosphorus, a rapidly rising two-dimensional material. Here, we report a molecular beam epitaxial growth of single layer blue phosphorus on Au(111) by using black phosphorus as precursor, through the combination of in situ low temperature scanning tunneling microscopy and density functional theory calculation. The structure of the as-grown single layer blue phosphorus on Au(111) is explained with a (4 × 4) blue phosphorus unit cell coinciding with a (5 × 5) Au(111) unit cell, and this is verified by the theoretical calculations. The electronic bandgap of single layer blue phosphorus on Au(111) is determined to be 1.10 eV by scanning tunneling spectroscopy measurement. The realization of epitaxial growth of large-scale and high quality atomic-layered blue phosphorus can enable the rapid development of novel electronic and optoelectronic devices based on this emerging two-dimensional material. PMID:27359041

  20. Epitaxial Growth of Single Layer Blue Phosphorus: A New Phase of Two-Dimensional Phosphorus.

    PubMed

    Zhang, Jia Lin; Zhao, Songtao; Han, Cheng; Wang, Zhunzhun; Zhong, Shu; Sun, Shuo; Guo, Rui; Zhou, Xiong; Gu, Cheng Ding; Yuan, Kai Di; Li, Zhenyu; Chen, Wei

    2016-08-10

    Blue phosphorus, a previously unknown phase of phosphorus, has been recently predicted by theoretical calculations and shares its layered structure and high stability with black phosphorus, a rapidly rising two-dimensional material. Here, we report a molecular beam epitaxial growth of single layer blue phosphorus on Au(111) by using black phosphorus as precursor, through the combination of in situ low temperature scanning tunneling microscopy and density functional theory calculation. The structure of the as-grown single layer blue phosphorus on Au(111) is explained with a (4 × 4) blue phosphorus unit cell coinciding with a (5 × 5) Au(111) unit cell, and this is verified by the theoretical calculations. The electronic bandgap of single layer blue phosphorus on Au(111) is determined to be 1.10 eV by scanning tunneling spectroscopy measurement. The realization of epitaxial growth of large-scale and high quality atomic-layered blue phosphorus can enable the rapid development of novel electronic and optoelectronic devices based on this emerging two-dimensional material.

  1. Anisotropic exciton Stark shift in black phosphorus

    NASA Astrophysics Data System (ADS)

    Chaves, A.; Low, Tony; Avouris, P.; ćakır, 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.

  2. Method of removing phosphorus impurities from yellowcake

    SciTech Connect

    Brown, R.A.; Winkley, D.C.

    1983-04-05

    PhospHorus impurities are removed from yellowcake by dissolving it in hydrochloric or sulfuric acid to a U/sub 3/O/sub 88/ assay of at least 150 g/l at a pH of 2; precipitating uranium peroxide W hydrogen peroxide while keeping the pH between 2.2 and 2.6 and recovering the uranium peroxide from the phosphorus impurities remaining in solution.

  3. [Effects of irrigation using dairy effluent on grain yield, phosphorus utilization and distribu- tion in soil profile in winter wheat-summer maize rotation system].

    PubMed

    Du, Hui-ying; Feng, Jie; Guo, Hai-gang; Wang, Feng; Zhang, Ke-qiang

    2015-08-01

    Field experiments of winter wheat-summer maize rotation were conducted in North China Plain irrigation area to explore the effects of wheat season irrigation with dairy effluent on grain yield, phosphorus uptake, accumulative phosphorus usage efficiency and phosphorus accumulation in soil. The results showed that the irrigation with dairy effluent significantly improved the yields of winter wheat and summer maize. With the increasing of P2O5 carried by dairy effluent into soil, winter wheat yield increased at first and then decreased. When the P2O5 increased 137 kg · hm(-2), winter wheat yield increased to the maximum (7646.4 kg · hm(-2)) and the phosphorus utilization rate was the highest (24.8%). But excessive phosphorus decreased the winter wheat yield and phosphorus utilization efficiency. Summer maize yield and phosphorus uptake increased with the increase of P2O5 carried by dairy effluent. The summer maize yield increased by 2222.4-2628.6 kg · hm(-2) and the phosphorus uptake increased by 13.9-21.1 kg · hm(-2) in contrast to the control (CK). Under conventional phosphorus fertilization at 88 kg · hm(-2), and the summer maize yield increased by 2235.0 kg · hm(-2) compared with CK. As the time of irrigation with dairy effluent increasing, the grain yield increased more significantly. The cumulative phosphorus utilization in this rotation system increased year by year. After six seasons of crop harvest, the cumulative phosphorus utilization rate increased into 40.0%-47.7%. Under the experimental condition, two times of irrigation with the dairy effluents in the winter wheat-summer maize rotation system was the best operating mode.

  4. [Effects of irrigation using dairy effluent on grain yield, phosphorus utilization and distribu- tion in soil profile in winter wheat-summer maize rotation system].

    PubMed

    Du, Hui-ying; Feng, Jie; Guo, Hai-gang; Wang, Feng; Zhang, Ke-qiang

    2015-08-01

    Field experiments of winter wheat-summer maize rotation were conducted in North China Plain irrigation area to explore the effects of wheat season irrigation with dairy effluent on grain yield, phosphorus uptake, accumulative phosphorus usage efficiency and phosphorus accumulation in soil. The results showed that the irrigation with dairy effluent significantly improved the yields of winter wheat and summer maize. With the increasing of P2O5 carried by dairy effluent into soil, winter wheat yield increased at first and then decreased. When the P2O5 increased 137 kg · hm(-2), winter wheat yield increased to the maximum (7646.4 kg · hm(-2)) and the phosphorus utilization rate was the highest (24.8%). But excessive phosphorus decreased the winter wheat yield and phosphorus utilization efficiency. Summer maize yield and phosphorus uptake increased with the increase of P2O5 carried by dairy effluent. The summer maize yield increased by 2222.4-2628.6 kg · hm(-2) and the phosphorus uptake increased by 13.9-21.1 kg · hm(-2) in contrast to the control (CK). Under conventional phosphorus fertilization at 88 kg · hm(-2), and the summer maize yield increased by 2235.0 kg · hm(-2) compared with CK. As the time of irrigation with dairy effluent increasing, the grain yield increased more significantly. The cumulative phosphorus utilization in this rotation system increased year by year. After six seasons of crop harvest, the cumulative phosphorus utilization rate increased into 40.0%-47.7%. Under the experimental condition, two times of irrigation with the dairy effluents in the winter wheat-summer maize rotation system was the best operating mode. PMID:26685601

  5. 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.

  6. Assessing phosphorus reduction efforts in the Everglades

    NASA Astrophysics Data System (ADS)

    Tretkoff, Ernie

    2011-05-01

    Years of agricultural and urban runoff have resulted in too much phosphorus in northern regions of the Florida Everglades. To deal with this problem, very large constructed wetlands, known as Stormwater Treatment Areas (STAs), have been built to strip phosphorus from runoff before the water enters protected Everglades areas. The more than $1 billion STA project currently relies on large areas (cells) of submerged aquatic vegetation (SAV) to absorb phosphorus as the final stage of treatment. To evaluate how well the treatment cells are functioning, as well as the potential lower limits of treatment, it is essential to have an accurate picture of the inflows, outflows, and background phosphorus levels. Juston and DeBusk made long-term measurements in one of the SAV cells. They found that after total phosphorous levels in the cells reached about 15 micrograms per liter, no more phosphorus removal occurred. They also analyzed inflow and outflow data from the cell and inferred background phosphorus concentrations for eight additional SAV cells. Background concentrations averaged around 16 micrograms per liter. (Water Resources Research, doi:10.1029/2010WR009294, 2011)

  7. Soil phosphorus constrains biodiversity across European grasslands.

    PubMed

    Ceulemans, Tobias; Stevens, Carly J; Duchateau, Luc; Jacquemyn, Hans; Gowing, David J G; Merckx, Roel; Wallace, Hilary; van Rooijen, Nils; Goethem, Thomas; Bobbink, Roland; Dorland, Edu; Gaudnik, Cassandre; Alard, Didier; Corcket, Emmanuel; Muller, Serge; Dise, Nancy B; Dupré, Cecilia; Diekmann, Martin; Honnay, Olivier

    2014-12-01

    Nutrient pollution presents a serious threat to biodiversity conservation. In terrestrial ecosystems, the deleterious effects of nitrogen pollution are increasingly understood and several mitigating environmental policies have been developed. Compared to nitrogen, the effects of increased phosphorus have received far less attention, although some studies have indicated that phosphorus pollution may be detrimental for biodiversity as well. On the basis of a dataset covering 501 grassland plots throughout Europe, we demonstrate that, independent of the level of atmospheric nitrogen deposition and soil acidity, plant species richness was consistently negatively related to soil phosphorus. We also identified thresholds in soil phosphorus above which biodiversity appears to remain at a constant low level. Our results indicate that nutrient management policies biased toward reducing nitrogen pollution will fail to preserve biodiversity. As soil phosphorus is known to be extremely persistent and we found no evidence for a critical threshold below which no environmental harm is expected, we suggest that agro-environmental schemes should include grasslands that are permanently free from phosphorus fertilization.

  8. Phosphorus removal and N₂O production in anaerobic/anoxic denitrifying phosphorus removal process: long-term impact of influent phosphorus concentration.

    PubMed

    Wang, Zhen; Meng, Yuan; Fan, Ting; Du, Yuneng; Tang, Jie; Fan, Shisuo

    2015-03-01

    This study was conducted to investigate the long-term impact of influent phosphorus concentration on denitrifying phosphorus removal and N2O production during denitrifying phosphorous removal process. The results showed that, denitrifying phosphate accumulating organisms (DPAOs) could become dominant populations quickly in anaerobic/anoxic SBR by providing optimum cultivating conditions, and the reactor performed well for denitrifying phosphorus removal. The influent phosphorus concentration significantly affected anaerobic poly-β-hydroxyalkanoates (PHA) synthesis, denitrifying phosphorus removal, and N2O production during the denitrifying phosphorus removal process. As the influent phosphorus concentration was more than 20 mg L(-1), the activity of DPAOs began to be inhibited due to the transformation of the available carbon source type. Meanwhile, N2O production was inhibited with the mitigation of anoxic NO2(-)-N accumulation. Adoption of a modified feeding could enhance denitrifying phosphorus removal and inhibit N2O production during denitrifying phosphorous removal processes.

  9. 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 μM) 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.

  10. Calcium and phosphorus fluxes during hemodialysis with low calcium dialysate.

    PubMed

    Hou, S H; Zhao, J; Ellman, C F; Hu, J; Griffin, Z; Spiegel, D M; Bourdeau, J E

    1991-08-01

    We evaluated the acute effects of varying dialysate calcium concentration on plasma concentrations and dialyzer fluxes of calcium and phosphorus in adult hemodialysis patients. Seven individuals with stable end-stage renal failure were dialyzed 4 hours, three times weekly. The effects of dialysates containing 1.75, 1.25, or 0.75 mmol/L (70.1, 50.1, or 30.1 mg/L) of calcium were compared. Each patient was studied once at each bath calcium concentration. Compared with the predialysis mean value of 2.27 mmol/L (9.1 mg/dL), plasma total calcium concentration increased, remained constant, or decreased with the 1.75-, 1.25-, or 0.75-mmol/L calcium dialysates, respectively. The 0.75-mmol/L calcium dialysate did not cause signs or symptoms of hypocalcemia (and the plasma calcium concentration did not fall below 1.80 mmol/L [7.2 mg/dL]). Plasma phosphorus concentrations decreased equally from a predialysis mean value of 2.16 mmol/L (6.7 mg/dL), regardless of the dialysate calcium concentration. After 4 hours of treatment with the three different dialysates, the cumulative calcium fluxes were significantly different. With 1.75 mmol/L calcium, mean bodily calcium accumulation was 21.9 mmol (879 mg). With 1.25 mmol/L, there was no net calcium flux. With 0.75 mmol/L, mean patient calcium loss was 5.8 mmol (231 mg). Mean phosphorus removal after 4 hours was 32.5 mmol (1,006 mg) and was unaffected by dialysate calcium concentration.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:1867178

  11. Estimate of dietary phosphorus intake using 24-h urine collection.

    PubMed

    Morimoto, Yuuka; Sakuma, Masae; Ohta, Hiroyuki; Suzuki, Akitsu; Matsushita, Asami; Umeda, Minako; Ishikawa, Makoto; Taketani, Yutaka; Takeda, Eiji; Arai, Hidekazu

    2014-07-01

    Increases in serum phosphorus levels and dietary phosphorus intake induces vascular calcification, arterial sclerosis and cardiovascular diseases. Limiting phosphorus intake is advisable, however, no assessment methods are capable of estimating dietary phosphorus intake. We hypothesized that urinary phosphorus excretion can be translated into estimation of dietary phosphorus intake, and we evaluated whether a 24-h urine collection method could estimate dietary phosphorus intake. Thirty two healthy subjects were recruited for this study. Subjects collected urine samples over 24 h and weighed dietary records. We calculated dietary protein intake and phosphorus intake from dietary records and urine collection, and investigated associations between the two methods in estimating protein and phosphorus intake. Significant positive correlations were observed between dietary records and UC for protein and phosphorus intake. The average intakes determined from dietary records were significantly higher than from urine collection for both protein and phosphorus. There was a significant positive correlation between both the phosphorus and protein difference in dietary records and urine collection. The phosphorus-protein ratio in urine collection was significantly higher than in dietary records. Our data indicated that the 24-h urine collection method can estimate the amount of dietary phosphorus intake, and the results were superior to estimation by weighed dietary record.

  12. Rapid and portable electrochemical quantification of phosphorus.

    PubMed

    Kolliopoulos, Athanasios V; Kampouris, Dimitrios K; Banks, Craig E

    2015-04-21

    Phosphorus is one of the key indicators of eutrophication levels in natural waters where it exists mainly as dissolved phosphorus. Various analytical protocols exist to provide an offsite analysis, and a point of site analysis is required. The current standard method recommended by the Environmental Protection Agency (EPA) for the detection of total phosphorus is colorimetric and based upon the color of a phosphomolybdate complex formed as a result of the reaction between orthophosphates and molybdates ions where ascorbic acid and antimony potassium tartrate are added and serve as reducing agents. Prior to the measurements, all forms of phosphorus are converted into orthophosphates via sample digestion (heating and acidifying). The work presented here details an electrochemical adaptation of this EPA recommended colorimetric approach for the measurement of dissolved phosphorus in water samples using screen-printed graphite macroelectrodes for the first time. This novel indirect electrochemical sensing protocol allows the determination of orthophosphates over the range from 0.5 to 20 μg L(-1) in ideal pH 1 solutions utilizing cyclic voltammetry with a limit of detection (3σ) found to correspond to 0.3 μg L(-1) of phosphorus. The reaction time and influence of foreign ions (potential interferents) upon this electroanalytical protocol was also investigated, where it was found that a reaction time of 5 min, which is essential in the standard colorimetric approach, is not required in the new proposed electrochemically adapted protocol. The proposed electrochemical method was independently validated through the quantification of orthophosphates and total dissolved phosphorus in polluted water samples (canal water samples) with ion chromatography and ICP-OES, respectively. This novel electrochemical protocol exhibits advantages over the established EPA recommended colorimetric determination for total phosphorus with lower detection limits and shorter experimental times

  13. Rapid and portable electrochemical quantification of phosphorus.

    PubMed

    Kolliopoulos, Athanasios V; Kampouris, Dimitrios K; Banks, Craig E

    2015-04-21

    Phosphorus is one of the key indicators of eutrophication levels in natural waters where it exists mainly as dissolved phosphorus. Various analytical protocols exist to provide an offsite analysis, and a point of site analysis is required. The current standard method recommended by the Environmental Protection Agency (EPA) for the detection of total phosphorus is colorimetric and based upon the color of a phosphomolybdate complex formed as a result of the reaction between orthophosphates and molybdates ions where ascorbic acid and antimony potassium tartrate are added and serve as reducing agents. Prior to the measurements, all forms of phosphorus are converted into orthophosphates via sample digestion (heating and acidifying). The work presented here details an electrochemical adaptation of this EPA recommended colorimetric approach for the measurement of dissolved phosphorus in water samples using screen-printed graphite macroelectrodes for the first time. This novel indirect electrochemical sensing protocol allows the determination of orthophosphates over the range from 0.5 to 20 μg L(-1) in ideal pH 1 solutions utilizing cyclic voltammetry with a limit of detection (3σ) found to correspond to 0.3 μg L(-1) of phosphorus. The reaction time and influence of foreign ions (potential interferents) upon this electroanalytical protocol was also investigated, where it was found that a reaction time of 5 min, which is essential in the standard colorimetric approach, is not required in the new proposed electrochemically adapted protocol. The proposed electrochemical method was independently validated through the quantification of orthophosphates and total dissolved phosphorus in polluted water samples (canal water samples) with ion chromatography and ICP-OES, respectively. This novel electrochemical protocol exhibits advantages over the established EPA recommended colorimetric determination for total phosphorus with lower detection limits and shorter experimental times

  14. Nitrogen, phosphorus, carbon and population.

    PubMed

    Gilland, Bernard

    2015-01-01

    Population growth makes food production increase necessary; economic growth increases demand for animal products and livestock feed. As further increase of the cropland area is ecologically undesirable, it is necessary to increase crop yields; this requires, inter alia, more nitrogen and phosphorus fertiliser despite the environmental problems which this will exacerbate. It is probable that a satisfactory food supply and an environmentally benign agriculture worldwide cannot be achieved without reducing population to approximately three billion. The reduction could be achieved by 2200 if the total fertility rate--currently 2.5--declined to 1.5 as a world average by 2050, and remained at that level until 2200, but the probability of such a global fertility trajectory is close to zero. It will also be necessary to replace fossil energy by nuclear and renewable energy in order to stabilise atmospheric carbon dioxide concentration, but the phase-out cannot be completed until the 22nd century, when the atmospheric concentration will be approximately 50% above the 2015 level of 400 ppm. PMID:26790176

  15. 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

  16. The renaissance of black phosphorus

    NASA Astrophysics Data System (ADS)

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

    2015-04-01

    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.

  17. Total Value of Phosphorus Recovery.

    PubMed

    Mayer, Brooke K; Baker, Lawrence A; Boyer, Treavor H; Drechsel, Pay; Gifford, Mac; Hanjra, Munir A; Parameswaran, Prathap; Stoltzfus, Jared; Westerhoff, Paul; Rittmann, Bruce E

    2016-07-01

    Phosphorus (P) is a critical, geographically concentrated, nonrenewable resource necessary to support global food production. In excess (e.g., due to runoff or wastewater discharges), P is also a primary cause of eutrophication. To reconcile the simultaneous shortage and overabundance of P, lost P flows must be recovered and reused, alongside improvements in P-use efficiency. While this motivation is increasingly being recognized, little P recovery is practiced today, as recovered P generally cannot compete with the relatively low cost of mined P. Therefore, P is often captured to prevent its release into the environment without beneficial recovery and reuse. However, additional incentives for P recovery emerge when accounting for the total value of P recovery. This article provides a comprehensive overview of the range of benefits of recovering P from waste streams, i.e., the total value of recovering P. This approach accounts for P products, as well as other assets that are associated with P and can be recovered in parallel, such as energy, nitrogen, metals and minerals, and water. Additionally, P recovery provides valuable services to society and the environment by protecting and improving environmental quality, enhancing efficiency of waste treatment facilities, and improving food security and social equity. The needs to make P recovery a reality are also discussed, including business models, bottlenecks, and policy and education strategies.

  18. 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.

  19. Total Value of Phosphorus Recovery.

    PubMed

    Mayer, Brooke K; Baker, Lawrence A; Boyer, Treavor H; Drechsel, Pay; Gifford, Mac; Hanjra, Munir A; Parameswaran, Prathap; Stoltzfus, Jared; Westerhoff, Paul; Rittmann, Bruce E

    2016-07-01

    Phosphorus (P) is a critical, geographically concentrated, nonrenewable resource necessary to support global food production. In excess (e.g., due to runoff or wastewater discharges), P is also a primary cause of eutrophication. To reconcile the simultaneous shortage and overabundance of P, lost P flows must be recovered and reused, alongside improvements in P-use efficiency. While this motivation is increasingly being recognized, little P recovery is practiced today, as recovered P generally cannot compete with the relatively low cost of mined P. Therefore, P is often captured to prevent its release into the environment without beneficial recovery and reuse. However, additional incentives for P recovery emerge when accounting for the total value of P recovery. This article provides a comprehensive overview of the range of benefits of recovering P from waste streams, i.e., the total value of recovering P. This approach accounts for P products, as well as other assets that are associated with P and can be recovered in parallel, such as energy, nitrogen, metals and minerals, and water. Additionally, P recovery provides valuable services to society and the environment by protecting and improving environmental quality, enhancing efficiency of waste treatment facilities, and improving food security and social equity. The needs to make P recovery a reality are also discussed, including business models, bottlenecks, and policy and education strategies. PMID:27214029

  20. 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.

  1. 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...

  2. Uptake and accumulation of phosphorus by dominant plant species growing in a phosphorus mining area.

    PubMed

    Xiao, Guangli; Li, Tingxuan; Zhang, Xizhou; Yu, Haiying; Huang, Huagang; Gupta, D K

    2009-11-15

    Phosphorus accumulation potentials were investigated for 12 dominant plant species growing in a phosphorus mining area in Shifang, as well as their corresponding non-mining ecotypes growing in Ya'an, China. High phosphorus concentrations were observed in the seedling and flowering stages of two species, Pilea sinofasciata and Polygonum hydropiper, up to 16.23 and 8.59 g kg(-1), respectively, which were 3.4 and 7 times higher than in the non-mining ecotypes. Available phosphorus levels in the respective rhizosphere soils of these plants were 112.84 and 121.78 mg kg(-1), 12 and 4 times higher than in the non-rhizosphere soil. Phosphorus concentrations in shoots of the mining ecotypes of all 12 species were significantly negatively correlated with available phosphorus in the rhizosphere soils (p<0.05), whereas a positive correlation was observed in the non-mining ecotypes. The biomass in shoot of the mining ecotype of P. hydropiper was nearly 2 times that in the non-mining ecotype. The results suggested that P. sinofasciata and P. hydropiper were efficient candidates among the tested species for phosphorus accumulation in shoots, and that further studies should be conducted to investigate their potential to be adopted as phosphorus accumulators.

  3. Rainfall intensity and phosphorus source effects on phosphorus transport in surface runoff from soil trays.

    PubMed

    Shigaki, Francirose; Sharpley, Andrew; Prochnow, Luis Ignacio

    2007-02-01

    Phosphorus runoff from agricultural fields amended with mineral fertilizers and manures has been linked to freshwater eutrophication. A rainfall simulation study was conducted to evaluate the effects of different rainfall intensities and P sources differing in water soluble P (WSP) concentration on P transport in runoff from soil trays packed with a Berks loam and grassed with annual ryegrass (Lolium multiflorum Lam.). Triple superphosphate (TSP; 79% WSP), low-grade super single phosphate (LGSSP; 50% WSP), North Carolina rock phosphate (NCRP; 0.5% WSP) and swine manure (SM; 70% WSP), were broadcast (100 kg total P ha-1) and rainfall applied at 25, 50 and 75 mm h-1 1, 7, 21, and 56 days after P source application. The concentration of dissolved reactive (DRP), particulate (PP), and total P (TP) was significantly (P<0.01) greater in runoff with a rainfall intensity of 75 than 25 mm h-1 for all P sources. Further, runoff DRP increased as P source WSP increased, with runoff from a 50 mm h-1 rain 1 day after source application having a DRP concentration of 0.25 mg L-1 for NCRP and 28.21 mg L-1 for TSP. In contrast, the proportion of runoff TP as PP was greater with low (39% PP for NCRP) than high WSP sources (4% PP for TSP) averaged for all rainfall intensities. The increased PP transport is attributed to the detachment and transport of undissolved P source particles during runoff. These results show that P source water solubility and rainfall intensity can influence P transport in runoff, which is important in evaluating the long-term risks of P source application on P transport in surface runoff.

  4. Estimation of phosphorus flux in rivers during flooding.

    PubMed

    Chen, Yen-Chang; Liu, Jih-Hung; Kuo, Jan-Tai; Lin, Cheng-Fang

    2013-07-01

    Reservoirs in Taiwan are inundated with nutrients that result in algal growth, and thus also reservoir eutrophication. Controlling the phosphorus load has always been the most crucial issue for maintaining reservoir water quality. Numerous agricultural activities, especially the production of tea in riparian areas, are conducted in watersheds in Taiwan. Nutrients from such activities, including phosphorus, are typically flushed into rivers during flooding, when over 90% of the yearly total amount of phosphorous enters reservoirs. Excessive or enhanced soil erosion from rainstorms can dramatically increase the river sediment load and the amount of particulate phosphorus flushed into rivers. When flow rates are high, particulate phosphorus is the dominant form of phosphorus, but sediment and discharge measurements are difficult during flooding, which makes estimating phosphorus flux in rivers difficult. This study determines total amounts of phosphorus transport by measuring flood discharge and phosphorous levels during flooding. Changes in particulate phosphorus, dissolved phosphorus, and their adsorption behavior during a 24-h period are analyzed owing to the fact that the time for particulate phosphorus adsorption and desorption approaching equilibrium is about 16 h. Erosion of the reservoir watershed was caused by adsorption and desorption of suspended solids in the river, a process which can be summarily described using the Lagmuir isotherm. A method for estimating the phosphorus flux in the Daiyujay Creek during Typhoon Bilis in 2006 is presented in this study. Both sediment and phosphorus are affected by the drastic discharge during flooding. Water quality data were collected during two flood events, flood in June 9, 2006 and Typhoon Bilis, to show the concentrations of suspended solids and total phosphorus during floods are much higher than normal stages. Therefore, the drastic changes of total phosphorus, particulate phosphorus, and dissolved phosphorus in

  5. Simulating soil phosphorus dynamics for a phosphorus loss quantification tool.

    PubMed

    Vadas, Peter A; Joern, Brad C; Moore, Philip A

    2012-01-01

    Pollution of fresh waters by agricultural phosphorus (P) is a water quality concern. Because soils can contribute significantly to P loss in runoff, it is important to assess how management affects soil P status over time, which is often done with models. Our objective was to describe and validate soil P dynamics in the Annual P Loss Estimator (APLE) model. APLE is a user-friendly spreadsheet model that simulates P loss in runoff and soil P dynamics over 10 yr for a given set of runoff, erosion, and management conditions. For soil P dynamics, APLE simulates two layers in the topsoil, each with three inorganic P pools and one organic P pool. It simulates P additions to soil from manure and fertilizer, distribution among pools, mixing between layers due to tillage and bioturbation, leaching between and out of layers, crop P removal, and loss by surface runoff and erosion. We used soil P data from 25 published studies to validate APLE's soil P processes. Our results show that APLE reliably simulated soil P dynamics for a wide range of soil properties, soil depths, P application sources and rates, durations, soil P contents, and management practices. We validated APLE specifically for situations where soil P was increasing from excessive P inputs, where soil P was decreasing due to greater outputs than inputs, and where soil P stratification occurred in no-till and pasture soils. Successful simulations demonstrate APLE's potential to be applied to major management scenarios related to soil P loss in runoff and erosion. PMID:23128732

  6. [Optimization and comparison of nitrogen and phosphorus removal by different aeration modes in oxidation ditch].

    PubMed

    Guo, Chang-Zi; Peng, Dang-Cong; Cheng, Xue-Mei; Wang, Dan

    2012-03-01

    The oxidation ditch operation mode was simulated by sequencing batch reactor (SBR) system with alternate stirring and aeration. The nitrogen and phosphorus removal efficiencies were investigated in two different aeration modes: point aeration and step aeration. Experimental results show that oxygen is dissolved more efficiently in point aeration mode with a longer aerobic region in the same air supply capacity, but dissolved oxygen (DO) utilization efficiency for nitrogen and phosphorus removal is high in step aeration mode. Nitrification abilities of the two modes are equal with ammonia-nitrogen (NH4(+) -N) removal efficiency of 96.68% and 97.03%, respectively. Nitrifier activities are 4.65 and 4.66 mg x (g x h)(-1) respectively. When the ratio of anoxic zones and the aerobic zones were 1, the total nitrogen (TN) removal efficiency of point aeration mode in 2, 4 or 7 partitions was respectively 60.14%, 47.93% and 33.7%. The total phosphorus (TP) removal efficiency was respectively 28.96%, 23.75% and 24.31%. The less the partitions, the higher the nitrogen and phosphorus removal efficiencies, but it is in more favor of TN removal. As for step aeration mode with only one partitioning zone, the TN and TP removal efficiencies are respectively 64.21% and 49.09%, which is better than in point aeration mode, but more conducive to the improvement of TP removal efficiency. Under the condition of sufficient nitrification in step aeration mode, the nitrogen and phosphorus removal is better with the increase of anoxic zone. The removal efficiencies of TN and TP respectively rose to 73.94% and 54.18% when the ratio of anoxic zones and the aerobic zones was increased from 1 : 1 to 1. 8 : 1. As the proportion of anoxic zones was enlarged further, nitrification and operation stability were weakened so as to affect the nitrogen and phosphorus removal efficiencies.

  7. [Long-Term Inhibition of FNA on Aerobic Phosphate Uptake and Variation of Phosphorus Uptake Properties of the Sludge].

    PubMed

    Ma, Juan; Li, Lu; Yu, Xiao-jun; Sun, Lei-jun; Sun, Hong-wei; Chen, Yong-zhi

    2015-10-01

    An alternating anaerobic/oxic ( An/O) sequencing batch reactor (SBR) was employed to investigate the long-term inhibitory effect of free nitrous acid (FNA) on aerobic phosphorus uptake performance and variation of phosphorus uptake properties of the sludge by adding nitrite. The reactor was started up under the condition of 21-23 degrees C. The results showed that FNA had no impact on phosphate release and uptake capacities of the sludge. However, the specific phosphate release/uptake rates was found to be higher. As FNA concentration (measure by HNO2-N) was lower than 0.53 x 10(-3) mg x L(-1), phosphorus removal efficiency of the system was higher than 96.9%. When the FNA concentration was increased to 0.99 x 10(-3) mg x L(-1), 1.46 x 10(-3) mg x L(-1) and 1.94 x 10(-3) mg x L(-1), the phosphorus removal performance deteriorated rapidly. The phosphorus removal efficiency was recovered to 64.42%, 67.33% and 44.14% after 50, 12 and 30 days, respectively, which implied the deterioration of phosphorus removal performance caused by FNA inhibition could be recovered and long-term acclimation could shorten the recovery process. Notably, increasing nitrite consumption appeared during aerobic phase with the concentration of FNA below 1.46 x 10(-3) mg x L(-1). It was also observed that the phosphorus uptake properties of the sludge varied after long-term inhibition. Nitrate and nitrite type anoxic phosphorus uptake capacity was increased by 3.35 and 3.86 times, respectively, suggesting long-term dosing FNA may facilitate the denitrifying of polyphosphate in organisms utilizing nitrite as electron acceptor. Moreover, long-term acclimation favored sludge settling. PMID:26841613

  8. Phosphorus and nitrogen physiology of two contrasting poplar genotypes when exposed to phosphorus and/or nitrogen starvation.

    PubMed

    Gan, Honghao; Jiao, Yu; Jia, Jingbo; Wang, Xinli; Li, Hong; Shi, Wenguang; Peng, Changhui; Polle, Andrea; Luo, Zhi-Bin

    2016-01-01

    Phosphorus (P) and nitrogen (N) are the two essential macronutrients for tree growth and development. To elucidate the P and N physiology of woody plants during acclimation to P and/or N starvation, we exposed saplings of the slow-growing Populus simonii Carr (Ps) and the fast-growing Populus × euramericana Dode (Pe) to complete nutrients or starvation of P, N or both elements (NP). P. × euramericana had lower P and N concentrations and greater P and N amounts due to higher biomass production, thereby resulting in greater phosphorus use efficiency/N use efficiency (PUE/NUE) compared with Ps. Compared with the roots of Ps, the roots of Pe exhibited higher enzymatic activities in terms of acid phosphatases (APs) and malate dehydrogenase (MDH), which are involved in P mobilization, and nitrate reductase (NR), glutamate synthase (GOGAT) and glutamate dehydrogenase (GDH), which participate in N assimilation. The responsiveness of the transcriptional regulation of key genes encoding transporters for phosphate, ammonium and nitrate was stronger in Pe than in Ps. These results suggest that Pe possesses a higher capacity for P/N uptake and assimilation, which promote faster growth compared with Ps. In both poplars, P or NP starvation caused significant decreases in the P concentrations and increases in PUE. Phosphorus deprivation induced the activity levels of APs, phosphoenolpyruvate carboxylase and MDH in both genotypes. Nitrogen or NP deficiency resulted in lower N concentrations, amino acid levels, NR and GOGAT activities, and higher NUE in both poplars. Thus, in Ps and Pe, the mRNA levels of PHT1;5, PHT1;9, PHT2;1, AMT2;1 and NR increased in the roots, while PHT1;9, PHO1;H1, PHO2, AMT1;1 and NRT2;1 increased in the leaves during acclimation to P, N or NP deprivation. These results suggest that both poplars suppress P/N uptake, mobilization and assimilation during acclimation to P, N or NP starvation.

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

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... phosphorus production subcategory. 422.10 Section 422.10 Protection of Environment ENVIRONMENTAL PROTECTION... Phosphorus Production Subcategory § 422.10 Applicability; description of the phosphorus production... production of phosphorus and ferrophosphorus by smelting of phosphate ore....

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

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... phosphorus production subcategory. 422.10 Section 422.10 Protection of Environment ENVIRONMENTAL PROTECTION... Phosphorus Production Subcategory § 422.10 Applicability; description of the phosphorus production... production of phosphorus and ferrophosphorus by smelting of phosphate ore....

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

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... phosphorus production subcategory. 422.10 Section 422.10 Protection of Environment ENVIRONMENTAL PROTECTION... Phosphorus Production Subcategory § 422.10 Applicability; description of the phosphorus production... production of phosphorus and ferrophosphorus by smelting of phosphate ore....

  12. 40 CFR 422.10 - Applicability; description of the phosphorus production subcategory.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... phosphorus production subcategory. 422.10 Section 422.10 Protection of Environment ENVIRONMENTAL PROTECTION... Phosphorus Production Subcategory § 422.10 Applicability; description of the phosphorus production... production of phosphorus and ferrophosphorus by smelting of phosphate ore....

  13. 40 CFR 422.10 - Applicability; description of the phosphorus production subcategory.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... phosphorus production subcategory. 422.10 Section 422.10 Protection of Environment ENVIRONMENTAL PROTECTION... Phosphorus Production Subcategory § 422.10 Applicability; description of the phosphorus production... production of phosphorus and ferrophosphorus by smelting of phosphate ore....

  14. Phosphorus cycling in the Early Aptian

    NASA Astrophysics Data System (ADS)

    Oakes, R.; Dittrich, M.; Wortmann, U. G.

    2012-12-01

    Phosphorus is an essential nutrient for living organisms. It is vital for the formation of ATP, the energy store in cells, and is needed for DNA synthesis. Seawater phosphorus concentration therefore plays a critical role in controlling marine productivity on geological timescales. The majority of research on the P cycle focuses on modern lacustrine and marine settings. This follows the necessity to gain a further understanding on the effects of agricultural fertilisers on nutrient cycling; in particular on the mechanisms which lead to eutrophication. These studies use sequential extraction to determine the speciation of P. The results suggest that bottom sediments can act as both a source and a sink of phosphorus; the role they assume depends on range of factors including bottom water oxygen concentrations, sedimentation rate and the concentration of iron. This study applies a sequential extraction method developed in modern sediments to sediments from the Early Cretaceous, specifically the Early Aptian. During this time, globally synchronous oceanic anoxic events (OAE's) appear in the rock record. It has been suggested that these events represent an increase in marine productivity combined with bottom water anoxia. Our study investigates whether the speciation of sedimentary phosphorus can be used to reconstruct P cycling at this time. Our samples are taken from pre-, syn- and post-OAE1a but are not from the organic matter rich layers. Our results show that the original fractions of phosphorus have been altered during diagenesis with the majority of phosphorus now being preserved as either apatite (Ca-P) or phosphorus in organic matter (Porg). The dominance of Ca-P is expected as it is thought that redox-sensitive forms of P undergo 'sink switching' during diagenesis and are preserved as Ca-P. The high concentration of Porg however, differs from previous studies which generally find that Ca-P or iron (oxyhydr)oxide associated phosphorus (Fe-P) are dominant

  15. 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.

  16. The Adequacy of Phosphorus Binder Prescriptions Among American Hemodialysis Patients

    PubMed Central

    Huml, Anne M.; Sullivan, Catherine M.; Leon, Janeen B.; Sehgal, Ashwini R.

    2013-01-01

    Because hemodialysis treatment has a limited ability to remove phosphorus, dialysis patients must restrict dietary phosphorus intake and use phosphorus binding medication. Among patients with restricted dietary phosphorus intake (1000 mg/d), phosphorus binders must bind about 250 mg of excess phosphorus per day and among patients with more typical phosphorus intake (1500 mg/d), binders must bind about 750 mg per day. To determine the phosphorus binding capacity of binder prescriptions among American hemodialysis patients, we undertook a cross-sectional study of a random sample of in-center chronic hemodialysis patients. We obtained data for one randomly selected patient from 244 facilities nationwide. About one-third of patients had hyperphosphatemia (serum phosphorus level > 5.5 mg/dL). Among the 224 patients prescribed binders, the mean phosphorus binding capacity was 256 mg/d (SD 143). 59% of prescriptions had insufficient binding capacity for restricted dietary phosphorus intake, and 100% had insufficient binding capacity for typical dietary phosphorus intake. Patients using two binders had a higher binding capacity than patients using one binder (451 vs. 236 mg/d, p <0.001). A majority of binder prescriptions have insufficient binding capacity to maintain phosphorus balance. Use of two binders results in higher binder capacity. Further work is needed to understand the impact of binder prescriptions on mineral balance and metabolism and to determine the value of substantially increasing binder prescriptions. PMID:23013171

  17. Secondary poisoning of kestrels by white phosphorus

    USGS Publications Warehouse

    Sparling, D.W.; Federoff, N.E.

    1997-01-01

    Since 1982, extensive waterfowl mortality due to white phosphorus (P4) has been observed at Eagle River Flats, a tidal marsh near Anchorage, Alaska. Ducks and swans that ingest P4 pellets become lethargic and may display severe convulsions. Intoxicated waterfowl attract raptors and gulls that feed on dead or dying birds. To determine if avian predators can be affected by secondary poisoning, we fed American kestrels (Falco sparverius) 10-day-old domestic chickens that had been dosed with white phosphorus. Eight of 15 kestrels fed intact chicks with a pellet of P4 implanted in their crops died within seven days. Three of 15 kestrels fed chicks that had their upper digestive tracts removed to eliminate any pellets of white phosphorus also died. Hematocrit and hemoglobin in kestrels decreased whereas lactate dehydrogenaseL, glucose, and alanine aminotransferase levels in plasma increased with exposure to contaminated chicks. Histological examination of liver and kidneys showed that the incidence and severity of lesions increased when kestrels were fed contaminated chicks. White phosphorus residues were measurable in 87% of the kestrels dying on study and 20% of the survivors. This study shows that raptors can become intoxicated either by ingesting portions of digestive tracts containing white phosphorus pellets or by consuming tissues of P4 contaminated prey.

  18. Absolute transition probabilities of phosphorus.

    NASA Technical Reports Server (NTRS)

    Miller, M. H.; Roig, R. A.; Bengtson, R. D.

    1971-01-01

    Use of a gas-driven shock tube to measure the absolute strengths of 21 P I lines and 126 P II lines (from 3300 to 6900 A). Accuracy for prominent, isolated neutral and ionic lines is estimated to be 28 to 40% and 18 to 30%, respectively. The data and the corresponding theoretical predictions are examined for conformity with the sum rules.-

  19. Effect of phosphorus-ion implantation on the corrosion resistance and biocompatibility of titanium.

    PubMed

    Krupa, D; Baszkiewicz, J; Kozubowski, J A; Barcz, A; Sobczak, J W; Biliński, A; Lewandowska-Szumieł, M; Rajchel, B

    2002-08-01

    This work presents data on the structure and corrosion resistance of titanium after phosphorus-ion implantation with a dose of 10(17)P/cm2. The ion energy was 25keV. Transmission electron microscopy was used to investigate the microstructure of the implanted layer. The chemical composition of the surface layer was examined by X-ray photoelectron spectroscopy and secondary ion mass spectrometry. The corrosion resistance was examined by electrochemical methods in a simulated body fluid at a temperature of 37 C. Biocompatibility tests in vitro were performed in a culture of human derived bone cells in direct contact with the materials tested. Both, the viability of the cells determined by an XTT assay and activity of the cells evaluated by alkaline phosphatase activity measurements in contact with implanted and non-implanted titanium samples were detected. The morphology of the cells spread on the surface of the materials examined was also observed. The results confirmed the biocompatibility of both phosphorus-ion-implanted and non-implanted titanium under the conditions of the experiment. As shown by transmission electron microscope results, the surface layer formed during phosphorus-ion implantation was amorphous. The results of electrochemical examinations indicate that phosphorus-ion implantation increases the corrosion resistance after short-term as well as long-term exposures.

  20. 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

  1. 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

  2. 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.

  3. 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.

  4. 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

  5. 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.

  6. Changes in labile phosphorus forms during maturation of vermicompost enriched with phosphorus-solubilizing and diazotrophic bacteria.

    PubMed

    Busato, Jader G; Lima, Lívia S; Aguiar, Natália O; Canellas, Luciano P; Olivares, Fábio L

    2012-04-01

    The aim of this study was to assess the effect of N(2)-fixing and P-solubilizing bacteria during maturation of vermicompost on phosphorus availability. A bacterial suspension containing Burkholderia silvatlantica, Burkholderia spp. and Herbaspirillum seropedicae was applied at the initial stage of vermicomposting. At the end of the incubation time (120days), the nitrogen content had increased by18% compared to uninoculated vermicompost. Water-soluble P was 106% higher in inoculated vermicompost while resin-extractable P increased during the initial vermicomposting stage and was 21% higher at 60days, but was the same in inoculated and uninoculated mature compost. The activity of acid phosphatase was 43% higher in inoculated than uninoculated vermicompost. These data suggest that the introduction of the mixed culture had beneficial effects on vermicompost maturation.

  7. 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

  8. [Effect of light and temperature on growth kinetics of Anabaena flosaquae under phosphorus limitation].

    PubMed

    Yin, Zhi-Kun; Li, Zhe; Wang, Sheng; Guo, Jin-Song; Xiao, Yan; Liu, Jing; Zhang, Ping

    2015-03-01

    Phosphorus, light and temperature are the key environmental factors leading to algae growth. But the effects of interaction between light and temperature on the growth of Anabaena flosaquae under phosphorus limitation were not well documented in literature. Anabaena flosaquae was selected for the study and lab-scale experiment and simulation were carried out. The results showed that the optimal temperature of Anabaena flosaquae was 20 degrees C under phosphorus limitation when the light intensity was constant, and the optimal light intensity (illuminance) of Anabaena flosaquae was 3 000 lx under phosphorus limitation when the temperature was constant. Based on model fitting and parameter calibration, the optimal temperature and light intensity of Anabaena flosaquae were 21.03 degress C ± 1.55 degrees C and 2 675.12 lx ± 262.93 lx, respectively. These data were close to the actual water environmental condition at the end of spring. Results of this study will provide important foundation for prediction of Anabaena blooms. PMID:25929064

  9. Effects of gender and body weight on fibroblast growth factor 23 responsiveness to estimated dietary phosphorus.

    PubMed

    Ohta, Hiroyuki; Sakuma, Masae; Suzuki, Akitsu; Morimoto, Yuuka; Ishikawa, Makoto; Umeda, Minako; Arai, Hidekazu

    2016-01-01

    Fibroblast growth factor 23 (FGF23) is a molecule involved in regulating phosphorus homeostasis. Although some studies indicated an association between serum FGF23 levels and sex, the association has not been fully investigated. The purpose of this study was to evaluate whether sex could influence FGF23 responsiveness to dietary phosphorus intake in healthy individuals. Thirty two healthy subjects between 21 and 28 years were recruited for this study. Subjects performed 24-hour urine collection and blood samples were collected. We estimated phosphorus intake (UC-P) from the urine collection (UC), and evaluated any association between UC-P and serum FGF23 levels. Subsequently, we compared serum FGF23 levels between males and females. Positive correlation was observed between UC-P and serum FGF23 levels. Serum FGF23 levels were significantly higher in males than in females. Serum FGF23 levels/UC-P was significantly higher in females than in males. There was no significant difference in serum FGF23 levels/UC-P/BW between the male and female groups. Our results indicate that there was no gender difference between FGF23 responsiveness to phosphorus intake per body weight.

  10. [Effect of light and temperature on growth kinetics of Anabaena flosaquae under phosphorus limitation].

    PubMed

    Yin, Zhi-Kun; Li, Zhe; Wang, Sheng; Guo, Jin-Song; Xiao, Yan; Liu, Jing; Zhang, Ping

    2015-03-01

    Phosphorus, light and temperature are the key environmental factors leading to algae growth. But the effects of interaction between light and temperature on the growth of Anabaena flosaquae under phosphorus limitation were not well documented in literature. Anabaena flosaquae was selected for the study and lab-scale experiment and simulation were carried out. The results showed that the optimal temperature of Anabaena flosaquae was 20 degrees C under phosphorus limitation when the light intensity was constant, and the optimal light intensity (illuminance) of Anabaena flosaquae was 3 000 lx under phosphorus limitation when the temperature was constant. Based on model fitting and parameter calibration, the optimal temperature and light intensity of Anabaena flosaquae were 21.03 degress C ± 1.55 degrees C and 2 675.12 lx ± 262.93 lx, respectively. These data were close to the actual water environmental condition at the end of spring. Results of this study will provide important foundation for prediction of Anabaena blooms.

  11. [Seasonal dynamics of nitrogen- and phosphorus absorption efficiency of wetland plants in Minjiang River estuary].

    PubMed

    Zhang, Wen-Long; Zeng, Cong-Sheng; Zhang, Lin-Hai; Wang, Wei-Qi; Lin, Yan; Ai, Jin-Quan

    2009-06-01

    Taking the native Phragmites australis and invasive Spartina alterniflora in Minjiang River estuary as test objectives, this paper studied the seasonal dynamics of their biomass and nitrogen- and phosphorus absorption efficiency. A typical single-peak curve was presented for the seasonal dynamics of aboveground biomass and nitrogen- and phosphorus absorption efficiency of the two species. P. australis had the maximum aboveground biomass (2195.33 g X m(-2)) in summer, while S. alterniflora had it (3670.02 g X m(-2)) in autumn. The total nitrogen (TN) and total phosphorus (TP) contents of P. australis reached the peak (21.06 g x m(-2) of TN and 1.12 g x m(-2) of TP) in summer and in autumn, respectively, while those of S. alterniflora all reached the peak (26.76 g x m(-2) of TN and 3.23 g x m(-2) of TP) in autumn. Both of the two species had a higher absorption efficiency in TN than in TP (P < 0.01), and S. alterniflora had a significantly higher absorption efficiency of TN and TP than P. australis (P < 0.05). To some extent, the N/P, C/N, and C/P ratios of plants could indicate the nitrogen- and phosphorus absorption efficiency of the plants.

  12. Enhancing combined biological nitrogen and phosphorus removal from wastewater by applying mechanically disintegrated excess sludge.

    PubMed

    Zubrowska-Sudol, Monika; Walczak, Justyna

    2015-06-01

    The goal of the study was to evaluate the possibility of applying disintegrated excess sludge as a source of organic carbon to enhance biological nitrogen and phosphorus removal. The experiment, performed in a sequencing batch reactor, consisted of two two-month series, without and with applying mechanically disintegrated excess sludge, respectively. The effects on carbon, nitrogen and phosphorus removal were observed. It was shown that the method allows enhancement of combined nitrogen and phosphorus removal. After using disintegrated sludge, denitrification effectiveness increased from 49.2 ± 6.8% to 76.2 ± 2.3%, which resulted in a decline in the NOx-N concentration in the effluent from the SBR by an average of 21.4 mg NOx-N/L. Effectiveness of biological phosphorus removal increased from 28.1 ± 11.3% to 96.2 ± 2.5%, thus resulting in a drop in the [Formula: see text] concentration in the effluent by, on average, 6.05 mg PO4(3-)-P/L. The application of disintegrated sludge did not deteriorate effluent quality in terms of COD and NH4(+)-N. The concentration of NH4(+)-N in both series averaged 0.16 ± 0.11 mg NH4(+)-N/L, and the concentration of COD was 15.36 ± 3.54 mg O2/L.

  13. Enhancing combined biological nitrogen and phosphorus removal from wastewater by applying mechanically disintegrated excess sludge.

    PubMed

    Zubrowska-Sudol, Monika; Walczak, Justyna

    2015-06-01

    The goal of the study was to evaluate the possibility of applying disintegrated excess sludge as a source of organic carbon to enhance biological nitrogen and phosphorus removal. The experiment, performed in a sequencing batch reactor, consisted of two two-month series, without and with applying mechanically disintegrated excess sludge, respectively. The effects on carbon, nitrogen and phosphorus removal were observed. It was shown that the method allows enhancement of combined nitrogen and phosphorus removal. After using disintegrated sludge, denitrification effectiveness increased from 49.2 ± 6.8% to 76.2 ± 2.3%, which resulted in a decline in the NOx-N concentration in the effluent from the SBR by an average of 21.4 mg NOx-N/L. Effectiveness of biological phosphorus removal increased from 28.1 ± 11.3% to 96.2 ± 2.5%, thus resulting in a drop in the [Formula: see text] concentration in the effluent by, on average, 6.05 mg PO4(3-)-P/L. The application of disintegrated sludge did not deteriorate effluent quality in terms of COD and NH4(+)-N. The concentration of NH4(+)-N in both series averaged 0.16 ± 0.11 mg NH4(+)-N/L, and the concentration of COD was 15.36 ± 3.54 mg O2/L. PMID:25776916

  14. [Bone and Nutrition. A novel function of phosphorus].

    PubMed

    Taketani, Yutaka; Imi, Yukiko; Abuduli, Maerjianghan

    2015-07-01

    Phosphorus is an essential nutrient for bone formation by forming hydroxyapatite with calcium. Simultaneously, phosphorus is also a component of high energy bond of ATP, nucleic acids, and phospholipids. Recent studies have demonstrated that excess or lack of dietary phosphorus intake may cause vascular dysfunction, cardiac hypertrophy, and impaired glucose tolerance. Here, we introduce recent findings about the effects of high or low dietary phosphorus intake on several organs except for bone.

  15. 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.

  16. 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.

  17. 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...

  18. 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...

  19. 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...

  20. 40 CFR 721.2752 - Epoxy resin containing phosphorus (generic).

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 32 2013-07-01 2013-07-01 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...

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

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 32 2012-07-01 2012-07-01 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...

  2. 40 CFR 721.2752 - Epoxy resin containing phosphorus (generic).

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 31 2014-07-01 2014-07-01 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...

  3. 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...

  4. 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...

  5. Availability of phosphorus contained in poultry litter for lambs.

    PubMed

    Tagari, H; Silanikove, N; Hurwitz, S

    1981-03-01

    Percentage net phosphorus availability (NPHA) and set phosphorus utilization (NPHU) of the phosphorus contained in a heat-sterilized poultry litter (PL) as compared to feed grade dicalcium phosphate (DCP) for lambs was assessed by the "slope" method. The method was based on the evaluation of the function of apparent phosphorus absorption (NPHA), or retention (NPHU), on phosphorus intake. Nitrogen retention was also evaluated. Plasma inorganic phosphorus concentration as a function of phosphorus intake was evaluated and compared to NPHA and NPHU. The percentage of NPHA was found to be 63.7 and 39, and that of NPHU was 63 and 38 for the phosphorus supplied by DCP and PL, respectively. Thus, the NPHA or NPHU for the phosphorus contained in PL is 60.9 and 60.3% of that of DCP, respectively. The slope ratio between the two phosphate supplements as observed for plasma inorganic phosphorus concentrations was similar to those found for NPHA and NPHU but the coefficient of variation was 5 times higher. Nitrogen digestibility was not affected by the level of phosphorus in the diets. Correlation between nitrogen retention and NPHA or NPHU was, however, significant (P less than 0.05). The slopes of dependence of N retention upon phosphorus intake were 2.81 and 1.6 (P less than 0.05) for DCP and PL treatments, respectively, and the ratio between the slopes was 0.57, close to the ratio of NPHU in PL to DCP-supplemented diets.

  6. 49 CFR 173.188 - White or yellow phosphorus.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 49 Transportation 2 2010-10-01 2010-10-01 false White or yellow phosphorus. 173.188 Section 173... Class 7 § 173.188 White or yellow phosphorus. Phosphorus, white or yellow, when offered for transportation or transported by rail, highway, or water, must be packaged in water or dry in...

  7. 49 CFR 173.188 - White or yellow phosphorus.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 49 Transportation 2 2011-10-01 2011-10-01 false White or yellow phosphorus. 173.188 Section 173... Class 7 § 173.188 White or yellow phosphorus. Phosphorus, white or yellow, when offered for transportation or transported by rail, highway, or water, must be packaged in water or dry in...

  8. 49 CFR 173.188 - White or yellow phosphorus.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 49 Transportation 2 2012-10-01 2012-10-01 false White or yellow phosphorus. 173.188 Section 173... Class 7 § 173.188 White or yellow phosphorus. Phosphorus, white or yellow, when offered for transportation or transported by rail, highway, or water, must be packaged in water or dry in...

  9. 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...

  10. 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.

  11. Osteophagia provide giraffes with phosphorus and calcium?

    PubMed

    Bredin, I P; Skinner, J D; Mitchell, G

    2008-03-01

    The daily requirement for calcium and phosphorus by giraffes to sustain the growth and maintenance of their skeletons is large. The source of sufficient calcium is browse. The source of necessary phosphorus is obscure, but it could be osteophagia, a frequently observed behaviour in giraffes. We have assessed whether bone ingested as a result of osteophagia can be digested in the rumen. Bone samples from cancellous (cervical vertebrae) and dense bones (metacarpal shaft) were immersed in the rumens of five sheep, for a period of up to 30 days, and the effect compared to immersion in distilled water and in artificial saliva for 30 days. Distilled water had no effect on the bones. Dense bone samples were softened by exposure to the saliva and rumen fluid, but did not lose either calcium or phosphorus. In saliva and rumen fluid the cancellous bone samples also softened, and their mass and volume decreased as a result of exposure to saliva, but in neither fluid did they lose significant amounts of calcium and phosphorus. We conclude that although saliva and rumen fluid can soften ingested bones, there is an insignificant digestion of bones in the rumen.

  12. 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...

  13. 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...

  14. 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.

  15. Potential phosphorus recovery by struvite formation.

    PubMed

    Jaffer, Y; Clark, T A; Pearce, P; Parsons, S A

    2002-04-01

    Formation of struvite (MgNH4PO4 x 6H2O) at sewage treatment works can cause operational problems and decrease efficiency. Struvite has a commercial value and the controlled formation and recovery of it would be beneficial. A mass balance was conducted at full scale across the whole sewage treatment plant in order to identify a stream to conduct bench-scale struvite crystallisation studies. The most suitable stream was identified as the centrifuge liquors. The average flow of the liquor stream was 393 m3 d(-1) and the composition was as follows: 167 mg L(-1) phosphorus, 44 mg L(-1) magnesium, 615 mg L(-1) ammonium, 56 mg L(-1) calcium and 2580 mg L(-1) of alkalinity. The pH averaged at 7.6 and the stream had a predicted struvite precipitation potential of 140 mg L(-1). Struvite crystallisation occurred quickly during the trials, by raising the pH of the centrifuge liquors to 9.0 and dosing with magnesium. Up to 97% phosphorus removal as struvite was achieved. Struvite formation occurred when the molar ratio of magnesium:phosphorus was at least 1.05:1. Below this ratio phosphorus removals of 72% were observed, but not exclusively as struvite. Annual yields of struvite were calculated to be 42-100 tonnes a year, depending on the dose regime. Revenue from the sale of produced struvite could be between Pound Sterling8400 and Pound Sterling20,000 a year. PMID:12044083

  16. Phosphorus retention capacity in red ferralitic soil.

    PubMed

    Pérez, M M; Bossens, J; Rosa, E; Tack, F M G

    2014-01-01

    In this study the main physical-chemical characteristics of red ferralitic soil to use as substrate in subsurface wetlands was determined. The P-removal was evaluated in a short-term isotherm batch experiment and in a column percolation experiment. The acid characteristic and high content of iron minerals in the red ferralitic soil facilitated the phosphorus removal. Also the sorption isotherms at two different temperatures were obtained. The results showed that the sorption capacity increases with an increase in solution temperature from 25 to 35 °C. The experimental data were fitted to Langmuir and Freundlich models, having a better fit to the Freundlich isotherms. The maximum P-sorption capacities estimated using the Langmuir isotherm were 0.96 and 1.13 g/kg at 25 and 35 °C respectively. Moreover a column experiment was carried out at two different flows. Sequential extractions of the phosphorus-saturated soil indicated that phosphorus is mainly bound with iron or aluminum minerals. The results have demonstrated a good potential for red ferralitic soil for phosphorus removal from urban wastewater. PMID:25401322

  17. 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....

  18. Lake Erie phosphorus loading and Cladophora updates

    EPA Science Inventory

    The presentation will focus on updates or progress being made on each Phosphorus Loadings and Cladophora for Lake Erie. The format will give a brief summary of data, findings, and results that were used by the Great Lakes Water Quality Agreement (GLWQA) Annex 4 Nutrients Modeli...

  19. Nanotubes based on monolayer blue phosphorus

    NASA Astrophysics Data System (ADS)

    Montes, E.; Schwingenschlögl, U.

    2016-07-01

    We demonstrate structural stability of monolayer zigzag and armchair blue phosphorus nanotubes by means of molecular dynamics simulations. The vibrational spectrum and electronic band structure are determined and analyzed as functions of the tube diameter and axial strain. The nanotubes are found to be semiconductors with a sensitive indirect band gap that allows flexible tuning.

  20. The role of phosphorus in chemical evolution.

    PubMed

    Maciá, Enrique

    2005-08-01

    In this tutorial review we consider the role of phosphorus and its compounds within the context of chemical evolution in galaxies. Following an interdisciplinary approach we first discuss the position of P among the main biogenic elements by considering its relevance in most essential biochemical functions as well as its peculiar chemistry under different physicochemical conditions. Then we review the phosphorus distribution in different cosmic sites, such as terrestrial planets, interplanetary dust particles, cometary dust, planetary atmospheres and the interstellar medium (ISM). In this way we realize that this element is both scarce and ubiquitous in the universe. These features can be related to the complex nucleosynthesis of P nuclide in the cores of massive stars under explosive conditions favouring a wide distribution of this element through the ISM, where it would be ready to react with other available atoms. A general tendency towards more oxidized phosphorus compounds is clearly appreciated as chemical evolution proceeds from circumstellar and ISM materials to protoplanetary and planetary condensed matter phases. To conclude we discuss some possible routes allowing for the incorporation of phosphorus compounds of prebiotic interest during the earlier stages of solar system formation.

  1. Temperature-dependant study of phosphorus ion implantation in germanium

    NASA Astrophysics Data System (ADS)

    Razali, M. A.; Smith, A. J.; Jeynes, C.; Gwilliam, R. M.

    2012-11-01

    We present experimental results on shallow junction formation in germanium by phosphorus ion implantation and standard rapid thermal processing. An attempt is made to improve phosphorus activation by implanting phosphorus at high and low temperature. The focus is on studying the germanium damage and phosphorus activation as a function of implant temperature. Rutherford backscattering spectrometry with channelling and Hall Effect measurements are employed for characterisation of germanium damage and phosphorus activation, respectively. High and low temperature implants were found to be better compared to room temperature implant.

  2. Phosphorus Retention Models for Tennessee Valley Authority Reservoirs

    NASA Astrophysics Data System (ADS)

    Higgins, John M.; Kim, Byung R.

    1981-06-01

    Data for the 18 largest Tennessee Valley Authority (TVA) reservoirs are compared with previously developed models for predicting steady state phosphorus concentrations in lakes. A plug flow model is presented for lakes and reservoirs which have significant longitudinal variation in phosphorus concentration. The results indicate that phosphorus sedimentation and retention coefficients developed for natural lakes are not directly applicable to TVA reservoirs. The apparent settling velocity of phosphorus in TVA reservoirs was substantially higher than previously reported values for natural lakes. Application of the plug flow model to Cherokee Reservoir showed good agreement with measured in-lake phosphorus concentrations.

  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

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

    PubMed

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

    2015-11-18

    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.

  5. 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

  6. 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.

  7. 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

  8. 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

  9. Isolating phosphorus from sludge in the presence of surfactants

    SciTech Connect

    Nikandrov, I.S.; Kogtev, S.E.; Solinov, I.A.

    1988-09-10

    The authors have examined extracting phosphorus by treatment with solutions containing surfactants, which were oleic acid, sodium tripolyphosphate, and trisodium phosphate, which were of pure or chemically pure grades. The phosphorus slime from the Kuibyshevfosfor Cooperative contained 68% elemental phosphorus; the slime from making red phosphorus at the Korund Cooperative contained 67% elemental phosphorus. The aqueous surfactant was added at an appropriate concentration in a ratio of five to the sludge. The ratio and the concentration providing a high degree of extraction were found in preliminary experiments. The decrease in phosphorus extraction as the temperature difference between the heating medium and the sludge in the reactor increases (it governs the boiling rate) to more than 40% is due to the properties changing on account of the rapid oxidation of the phosphorus and the partial steam distillation. The surfactant isolated from the solution after filtration is suitable for second treatment of new sludge batches.

  10. [Spatiotemporal characteristics of nitrogen and phosphorus in a mountainous urban lake].

    PubMed

    Bao, Jing-Yue; Bao, Jian-Guo; Li, Li-Qing

    2014-10-01

    Longjing Lake in Chongqing Expo Garden is a typical representative of mountainous urban lake. Based on water quality monitoring of Longjing Lake, spatiotemporal characteristics of nitrogen and phosphorus and their relations were analyzed, combined with natural and human factors considered. The results indicated that annual average concentrations of TN and TP in overall lake were (1.42 ± 0.46) mg · L(-1) and (0.09 ± 0.03) mg · L(-1), nitrogen and phosphorus concentrations fluctuated seasonally which were lower during the flooding season than those during the dry season. Nitrogen and phosphorus concentration in main water area, open water areas and bay areas of Longjing Lake were distributed with temporal and spatial heterogeneity by different regional influencing factors. The seasonal variation of the main water area was basically consistent with overall lake. Two open water areas respectively connected the main water area with the upstream region, bay areas. TN and TP concentrations were gradually reduced along the flow direction. Upstream water quality and surrounding park functional layout impacted nitrogen and phosphorus nutrient concentrations of open water areas. Nutrient concentrations of typical bay areas were higher than those of main water area and open water areas. The mean mass fraction of PN/TN and PP/TP accounted for a large proportion (51.7% and 72.8%) during the flooding season, while NO(3-)-N/TN and SRP/TP accounted for more (42.0% and 59.4%) during the dry season. The mass fraction of ammonia nitrogen and dissolved organic nitrogen in total nitrogen were relatively stable. The annual mean of N/P ratio was 18.429 ± 7.883; the period of nitrogen limitation was 5.3% while was 21.2% for phosphorus limitation.

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

    PubMed

    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. PMID:26733966

  12. Innovative Method for Separating Phosphorus and Iron from High-Phosphorus Oolitic Hematite by Iron Nugget Process

    NASA Astrophysics Data System (ADS)

    Han, Hongliang; Duan, Dongping; Wang, Xing; Chen, Siming

    2014-10-01

    This study puts forward a new method to separate phosphorus and iron from high-phosphorus oolitic hematite through iron nuggets process. Firstly, the physical, chemical, and microscopic characteristics of high-phosphorus oolitic hematite are investigated. Then, the reaction mechanisms of high-phosphorus hematite together with feasibility to separating phosphorus and iron by iron nugget process are discussed. Meanwhile, the experiments of high-phosphorus hematite used in rotary hearth furnace iron nugget processes are studied as well. The results indicate that the iron nugget process is a feasible and efficient method for iron and phosphorus separation of high-phosphorus oolitic hematite. The phosphorus content in iron nuggets is relatively low. Through the optimization of process parameters, the lowest of phosphorus in iron nuggets is 0.22 pct, the dephosphorization rate is above 86 pct, and the recovery of Fe is above 85 pct by the iron nugget process. This study aims to provide a theoretical and technical basis for economical and rational use of high-phosphorus oolitic hematite.

  13. Potential Impact of Dietary Choices on Phosphorus Recycling and Global Phosphorus Footprints: The Case of the Average Australian City

    PubMed Central

    Metson, Geneviève S.; Cordell, Dana; Ridoutt, Brad

    2016-01-01

    Changes in human diets, population increases, farming practices, and globalized food chains have led to dramatic increases in the demand for phosphorus fertilizers. Long-term food security and water quality are, however, threatened by such increased phosphorus consumption, because the world’s main source, phosphate rock, is an increasingly scarce resource. At the same time, losses of phosphorus from farms and cities have caused widespread water pollution. As one of the major factors contributing to increased phosphorus demand, dietary choices can play a key role in changing our resource consumption pathway. Importantly, the effects of dietary choices on phosphorus management are twofold: First, dietary choices affect a person or region’s “phosphorus footprint” – the magnitude of mined phosphate required to meet food demand. Second, dietary choices affect the magnitude of phosphorus content in human excreta and hence the recycling- and pollution-potential of phosphorus in sanitation systems. When considering options and impacts of interventions at the city scale (e.g., potential for recycling), dietary changes may be undervalued as a solution toward phosphorus sustainability. For example, in an average Australian city, a vegetable-based diet could marginally increase phosphorus in human excreta (an 8% increase). However, such a shift could simultaneously dramatically decrease the mined phosphate required to meet the city resident’s annual food demand by 72%. Taking a multi-scalar perspective is therefore key to fully exploring dietary choices as one of the tools for sustainable phosphorus management.

  14. Potential Impact of Dietary Choices on Phosphorus Recycling and Global Phosphorus Footprints: The Case of the Average Australian City

    PubMed Central

    Metson, Geneviève S.; Cordell, Dana; Ridoutt, Brad

    2016-01-01

    Changes in human diets, population increases, farming practices, and globalized food chains have led to dramatic increases in the demand for phosphorus fertilizers. Long-term food security and water quality are, however, threatened by such increased phosphorus consumption, because the world’s main source, phosphate rock, is an increasingly scarce resource. At the same time, losses of phosphorus from farms and cities have caused widespread water pollution. As one of the major factors contributing to increased phosphorus demand, dietary choices can play a key role in changing our resource consumption pathway. Importantly, the effects of dietary choices on phosphorus management are twofold: First, dietary choices affect a person or region’s “phosphorus footprint” – the magnitude of mined phosphate required to meet food demand. Second, dietary choices affect the magnitude of phosphorus content in human excreta and hence the recycling- and pollution-potential of phosphorus in sanitation systems. When considering options and impacts of interventions at the city scale (e.g., potential for recycling), dietary changes may be undervalued as a solution toward phosphorus sustainability. For example, in an average Australian city, a vegetable-based diet could marginally increase phosphorus in human excreta (an 8% increase). However, such a shift could simultaneously dramatically decrease the mined phosphate required to meet the city resident’s annual food demand by 72%. Taking a multi-scalar perspective is therefore key to fully exploring dietary choices as one of the tools for sustainable phosphorus management. PMID:27617261

  15. Legume nodules from nutrient-poor soils exhibit high plasticity of cellular phosphorus recycling and conservation during variable phosphorus supply.

    PubMed

    Vardien, Waafeka; Steenkamp, Emma T; Valentine, Alexander J

    2016-02-01

    Nitrogen fixing legumes rely on phosphorus for nodule formation, nodule function and the energy costs of fixation. Phosphorus is however very limited in soils, especially in ancient sandstone-derived soils such as those in the Cape Floristic Region of South Africa. Plants growing in such areas have evolved the ability to tolerate phosphorus stress by eliciting an array of physiological and biochemical responses. In this study we investigated the effects of phosphorus limitation on N2 fixation and phosphorus recycling in the nodules of Virgilia divaricata (Adamson), a legume native to the Cape Floristic Region. In particular, we focused on nutrient acquisition efficiencies, phosphorus fractions and the exudation and accumulation of phosphatases. Our finding indicate that during low phosphorus supply, V. divaricata internally recycles phosphorus and has a lower uptake rate of phosphorus, as well as lower levels adenylates but greater levels of phosphohydrolase exudation suggesting it engages in recycling internal nodule phosphorus pools and making use of alternate bypass routes in order to conserve phosphorus.

  16. Potential Impact of Dietary Choices on Phosphorus Recycling and Global Phosphorus Footprints: The Case of the Average Australian City.

    PubMed

    Metson, Geneviève S; Cordell, Dana; Ridoutt, Brad

    2016-01-01

    Changes in human diets, population increases, farming practices, and globalized food chains have led to dramatic increases in the demand for phosphorus fertilizers. Long-term food security and water quality are, however, threatened by such increased phosphorus consumption, because the world's main source, phosphate rock, is an increasingly scarce resource. At the same time, losses of phosphorus from farms and cities have caused widespread water pollution. As one of the major factors contributing to increased phosphorus demand, dietary choices can play a key role in changing our resource consumption pathway. Importantly, the effects of dietary choices on phosphorus management are twofold: First, dietary choices affect a person or region's "phosphorus footprint" - the magnitude of mined phosphate required to meet food demand. Second, dietary choices affect the magnitude of phosphorus content in human excreta and hence the recycling- and pollution-potential of phosphorus in sanitation systems. When considering options and impacts of interventions at the city scale (e.g., potential for recycling), dietary changes may be undervalued as a solution toward phosphorus sustainability. For example, in an average Australian city, a vegetable-based diet could marginally increase phosphorus in human excreta (an 8% increase). However, such a shift could simultaneously dramatically decrease the mined phosphate required to meet the city resident's annual food demand by 72%. Taking a multi-scalar perspective is therefore key to fully exploring dietary choices as one of the tools for sustainable phosphorus management. PMID:27617261

  17. 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. PMID:26733966

  18. Potential Impact of Dietary Choices on Phosphorus Recycling and Global Phosphorus Footprints: The Case of the Average Australian City.

    PubMed

    Metson, Geneviève S; Cordell, Dana; Ridoutt, Brad

    2016-01-01

    Changes in human diets, population increases, farming practices, and globalized food chains have led to dramatic increases in the demand for phosphorus fertilizers. Long-term food security and water quality are, however, threatened by such increased phosphorus consumption, because the world's main source, phosphate rock, is an increasingly scarce resource. At the same time, losses of phosphorus from farms and cities have caused widespread water pollution. As one of the major factors contributing to increased phosphorus demand, dietary choices can play a key role in changing our resource consumption pathway. Importantly, the effects of dietary choices on phosphorus management are twofold: First, dietary choices affect a person or region's "phosphorus footprint" - the magnitude of mined phosphate required to meet food demand. Second, dietary choices affect the magnitude of phosphorus content in human excreta and hence the recycling- and pollution-potential of phosphorus in sanitation systems. When considering options and impacts of interventions at the city scale (e.g., potential for recycling), dietary changes may be undervalued as a solution toward phosphorus sustainability. For example, in an average Australian city, a vegetable-based diet could marginally increase phosphorus in human excreta (an 8% increase). However, such a shift could simultaneously dramatically decrease the mined phosphate required to meet the city resident's annual food demand by 72%. Taking a multi-scalar perspective is therefore key to fully exploring dietary choices as one of the tools for sustainable phosphorus management.

  19. Does quantifying antecedent flow conditions improve stream phosphorus export estimation?

    NASA Astrophysics Data System (ADS)

    Warner, Stuart; Kiely, Gerard; Morgan, Gerard; O'Halloran, John

    2009-11-01

    SummaryA reliable and economical method for the estimation of nutrient export (e.g. phosphorus) in stream flow from catchments is necessary to quantify the impact of land use or land use change upon aquatic systems. The transport of phosphorus (P) from soil to water is known to impact negatively on water quality. A key observation from studies is that most P export occurs during high stream flow. However, it is not yet clear how flood-antecedent conditions affect the P export during flood events. In this study, the P loss from soil to water as represented by soluble reactive phosphorus (SRP) in stream waters from three different catchments, varying in land use, scale and location in Ireland was monitored over 1 year. This study examined the role of antecedent stream flow conditions on SRP export and identifies a catchment-specific relationship between SRP flood event load (EL) and a flow ratio (FR). The FR is defined as the ratio of the flood event volume (EV) to the pre-event volume (PEV). The latter is the cumulative flow volume for a number of days preceding the event. This PEV period was found to be longer (average 81 days) in the grassland catchments which were known to be saturated with soil P than in the forested catchments (average 21 days) with minimal soil P. This FR ratio is a measure of the antecedent hydrological state (wet or dry) of the catchment. For SRP for each catchment, a specific relationship between SRP EL and FR was identified. The annual SRP export was estimated, using this ratio and compared with the concentration/discharge ( C/ Q) method. The new flow ratio method was used with data from 12 flood events during the year to estimate an annual export of SRP. For the two grassland catchments in the study, using the FR method, we estimated an SRP export of 1.77 and 0.41 kg ha -1 yr -1. Using the C/ Q method, for the same sites, our estimate of SRP export was 1.70 and 0.50 kg ha -1 yr -1 respectively. The C/ Q method used SRP concentrations

  20. Phosphorus leaching from biosolids-amended sandy soils.

    PubMed

    Elliott, H A; O'Connor, G A; Brinton, S

    2002-01-01

    Increasing emphasis on phosphorus (P)-based nutrient management underscores the need to understand P behavior in soils amended with biosolids and manures. Laboratory and greenhouse column studies characterized P forms and leachability of eight biosolids products, chicken manure (CM), and commercial fertilizer (triple superphosphate, TSP). Bahiagrass (Paspalum notatum Flugge) was grown for 4 mo on two acid, P-deficient Florida sands, representing both moderate (Candler series: hyperthermic, uncoated Typic Quartzipsamments) and very low (Immokalee series: sandy, siliceous, hyperthermic Arenic Alaquods) P-sorbing capacities. Amendments were applied at 56 and 224 kg P(T) ha(-1), simulating P-based and N-based nutrient loadings, respectively. Column leachate P was dominantly inorganic and lower for biosolids P sources than TSP. For Candler soil, only TSP at the high P rate exhibited P leaching statistically greater (alpha = 0.05) than control (soil-only) columns. For the high P rate and low P-sorbing Immokalee soil, TSP and CM leached 21 and 3.0% of applied P, respectively. Leachate P for six biosolids was <1.0% of applied P and not statistically different from controls. Largo biosolids, generated from a biological P removal process, exhibited significantly greater leachate P in both cake and pelletized forms (11 and 2.5% of applied P, respectively) than other biosolids. Biosolids P leaching was correlated to the phosphorus saturation index (PSI = [Pox]/[Al(ox) + Fe(ox)]) based on oxalate extraction of the pre-applied biosolids. For hiosolids with PSI < or = approximately 1.1, no appreciable leaching occurred. Only Largo cake (PSI = 1.4) and pellets (PSI = 1.3) exhibited P leaching losses statistically greater than controls. The biosolids PSI appears useful for identifying biosolids with potential to enrich drainage P when applied to low P-sorbing soils. PMID:11931462

  1. Assessment of conservation easements, total phosphorus, and total suspended solids in West Fork Beaver Creek, Minnesota, 1999-2012

    USGS Publications Warehouse

    Christensen, Victoria G.; Kieta, Kristen A.

    2014-01-01

    This study examined conservation easements and their effectiveness at reducing phosphorus and solids transport to streams. The U.S. Geological Survey cooperated with the Minnesota Board of Water and Soil Resources and worked collaboratively with the Hawk Creek Watershed Project to examine the West Fork Beaver Creek Basin in Renville County, which has the largest number of Reinvest In Minnesota land retirement contracts in the State (as of 2013). Among all conservation easement programs, a total of 24,218 acres of agricultural land were retired throughout Renville County, and 2,718 acres were retired in the West Fork Beaver Creek Basin from 1987 through 2012. Total land retirement increased steadily from 1987 until 2000. In 2000, land retirement increased sharply because of the Minnesota River Conservation Reserve Enhancement Program, then leveled off when the program ended in 2002. Streamflow data were collected during 1999 through 2011, and total phosphorus and total suspended solids data were collected during 1999 through 2012. During this period, the highest peak streamflow of 1,320 cubic feet per second was in March 2010. Total phosphorus and total suspended solids are constituents that tend to increase with increases in streamflow. Annual flow-weighted mean total-phosphorus concentrations ranged from 0.140 to 0.759 milligrams per liter, and annual flow-weighted mean total suspended solids concentrations ranged from 21.3 to 217 milligrams per liter. Annual flow-weighted mean total phosphorus and total suspended solids concentrations decreased steadily during the first 4 years of water-quality sample collection. A downward trend in flow-weighted mean total-phosphorus concentrations was significant from 1999 through 2008; however, flow-weighted total-phosphorus concentrations increased substantially in 2009, and the total phosphorus trend was no longer significant. The high annual flow-weighted mean concentrations for total phosphorus and total suspended solids

  2. [Radioactivity of phosphorus implanted TiNi alloy].

    PubMed

    Zhao, Xingke; Cai, Wei; Zhao, Liancheng

    2003-09-01

    Exposed to neutron flow, the phosphorus implanted TiNi alloy gets radioactive. This radioactive material is used in vascular stent for prevention and cure of restenosis. Phosphorus implantation is carried out in a plasma immerged ion implantation system, and the dose of phosphorus implantation is in the range of 2-10 x 10(17) cm-2. After ion implantation, the alloy is exposed to the slow neutron flow in a nuclear reactor, the dose of the slow neutron is 1.39-5.88 x 10(19) n/cm2. The radioactivity of the TiNi alloy was measured by liquid scintillation spectrometry and radio-chromic-film dosimetry. The result shows that whether the phosphorus is implanted or not, the TiNi alloy comes to be radioactive after exposure to neutron flow. Just after neutron irradiation, the radiation dose of phosphorus implanted TiNi alloy is about one hundred times higher than that of un-phosphorus implanted TiNi alloy. The radiation difference between phosphorus and un-phosphorus implanted alloy decreases as time elapses. Within three months after neutron irradiation, the average half-decay period of phosphorus implanted TiNi alloy is about 62 days. The radiation ray penetration of phosphorus implanted TiNi alloy is deeper than that of pure 32P; this is of benefit to making radiation uniformity between stent struts and reducing radiation grads beyond the edge of stent.

  3. Patient education for phosphorus management in chronic kidney disease

    PubMed Central

    Kalantar-Zadeh, Kamyar

    2013-01-01

    Objectives: This review explores the challenges and solutions in educating patients with chronic kidney disease (CKD) to lower serum phosphorus while avoiding protein insufficiency and hypercalcemia. Methods: A literature search including terms “hyperphosphatemia,” “patient education,” “food fatigue,” “hypercalcemia,” and “phosphorus–protein ratio” was undertaken using PubMed. Results: Hyperphosphatemia is a strong predictor of mortality in advanced CKD and is remediated via diet, phosphorus binders, and dialysis. Dietary counseling should encourage the consumption of foods with the least amount of inorganic or absorbable phosphorus, low phosphorus-to-protein ratios, and adequate protein content, and discourage excessive calcium intake in high-risk patients. Emerging educational initiatives include food labeling using a “traffic light” scheme, motivational interviewing techniques, and the Phosphate Education Program – whereby patients no longer have to memorize the phosphorus content of each individual food component, but only a “phosphorus unit” value for a limited number of food groups. Phosphorus binders are associated with a clear survival advantage in CKD patients, overcome the limitations associated with dietary phosphorus restriction, and permit a more flexible approach to achieving normalization of phosphorus levels. Conclusion: Patient education on phosphorus and calcium management can improve concordance and adherence and empower patients to collaborate actively for optimal control of mineral metabolism. PMID:23667310

  4. Microstructural characterization of superalloy 718 with boron and phosphorus additions

    SciTech Connect

    Horton, J.A.; McKamey, C.G.; Miller, M.K.; Cao, W.D.; Kennedy, R.L.

    1997-06-01

    Boron and phosphorus additions are known to improve the stress rupture properties of IN-718. One possible mechanism to explain this property improvement relies on the boron and phosphorus additions slowing down the growth of {gamma}{double_prime} and {gamma}{prime} precipitates during high temperature service or aging. However, atom probe analysis found no segregation of boron and phosphorus to {gamma}-{gamma}{double_prime} or to {gamma}-{gamma}{prime} interfaces in the alloys with the high boron and high phosphorus levels. No difference in growth rates were found by transmission electron microscopy in the sizes of the {gamma}{double_prime} or {gamma}{prime} in alloys with high phosphorus and high boron as compared to commercial alloys and to alloys with even lower levels of phosphorus and boron. Atom probe analysis further found that much of the phosphorus, boron, and carbon segregated to grain boundaries. Creep curves comparing the alloys with high levels of phosphorus and boron and alloys with low levels of phosphorus and boron show a large difference in strain rate in the first hours of the test. These results suggest that the boron and phosphorus may have a direct effect on dislocation mobility by some pinning mechanism.

  5. [Research progress on phosphorus budgets and regulations in reservoirs].

    PubMed

    Shen, Xiao; Li, Xu; Zhang, Wang-shou

    2014-12-01

    Phosphorus is an important limiting factor of water eutrophication. A clear understanding of its budget and regulated method is fundamental for reservoir ecological health. In order to pro- mote systematic research further and improve phosphorus regulation system, the budget balance of reservoir phosphorus and its influencing factors were concluded, as well as conventional regulation and control measures. In general, the main phosphorus sources of reservoirs include upstream input, overland runoff, industrial and domestic wastewater, aquaculture, atmospheric deposition and sediment release. Upstream input is the largest phosphorus source among them. The principal output path of phosphorus is the flood discharge, the emission load of which is mainly influenced by drainage patterns. In addition, biological harvest also can export a fraction of phosphorus. There are some factors affecting the reservoir phosphorus balance, including reservoirs' function, hydrological conditions, physical and chemical properties of water, etc. Therefore, the phosphorus budgets of different reservoirs vary greatly, according to different seasons and regions. In order to reduce the phosphorus loading in reservoirs, some methods are carried out, including constructed wetlands, prefix reservoir, sediment dredging, biomanipulation, etc. Different methods need to be chosen and combined according to different reservoirs' characteristics and water quality management goals. Thus, in the future research, it is reasonable to highlight reservoir ecological characteristics and proceed to a complete and systematic analysis of the inherent complexity of phosphorus budget and its impact factors for the reservoirs' management. Besides, the interaction between phosphorus budget and other nutrients in reservoirs also needs to be conducted. It is fundamental to reduce the reservoirs' phosphorus loading to establish a scientific and improved management system based on those researches.

  6. [Research progress on phosphorus budgets and regulations in reservoirs].

    PubMed

    Shen, Xiao; Li, Xu; Zhang, Wang-shou

    2014-12-01

    Phosphorus is an important limiting factor of water eutrophication. A clear understanding of its budget and regulated method is fundamental for reservoir ecological health. In order to pro- mote systematic research further and improve phosphorus regulation system, the budget balance of reservoir phosphorus and its influencing factors were concluded, as well as conventional regulation and control measures. In general, the main phosphorus sources of reservoirs include upstream input, overland runoff, industrial and domestic wastewater, aquaculture, atmospheric deposition and sediment release. Upstream input is the largest phosphorus source among them. The principal output path of phosphorus is the flood discharge, the emission load of which is mainly influenced by drainage patterns. In addition, biological harvest also can export a fraction of phosphorus. There are some factors affecting the reservoir phosphorus balance, including reservoirs' function, hydrological conditions, physical and chemical properties of water, etc. Therefore, the phosphorus budgets of different reservoirs vary greatly, according to different seasons and regions. In order to reduce the phosphorus loading in reservoirs, some methods are carried out, including constructed wetlands, prefix reservoir, sediment dredging, biomanipulation, etc. Different methods need to be chosen and combined according to different reservoirs' characteristics and water quality management goals. Thus, in the future research, it is reasonable to highlight reservoir ecological characteristics and proceed to a complete and systematic analysis of the inherent complexity of phosphorus budget and its impact factors for the reservoirs' management. Besides, the interaction between phosphorus budget and other nutrients in reservoirs also needs to be conducted. It is fundamental to reduce the reservoirs' phosphorus loading to establish a scientific and improved management system based on those researches. PMID:25876422

  7. Controlled Sculpture of Black Phosphorus Nanoribbons.

    PubMed

    Masih Das, Paul; Danda, Gopinath; Cupo, Andrew; Parkin, William M; Liang, Liangbo; Kharche, Neerav; Ling, Xi; Huang, Shengxi; Dresselhaus, Mildred S; Meunier, Vincent; Drndić, Marija

    2016-06-28

    Black phosphorus (BP) is a highly anisotropic allotrope of phosphorus with great promise for fast functional electronics and optoelectronics. We demonstrate the controlled structural modification of few-layer BP along arbitrary crystal directions with sub-nanometer precision for the formation of few-nanometer-wide armchair and zigzag BP nanoribbons. Nanoribbons are fabricated, along with nanopores and nanogaps, using a combination of mechanical-liquid exfoliation and in situ transmission electron microscopy (TEM) and scanning TEM nanosculpting. We predict that the few-nanometer-wide BP nanoribbons realized experimentally possess clear one-dimensional quantum confinement, even when the systems are made up of a few layers. The demonstration of this procedure is key for the development of BP-based electronics, optoelectronics, thermoelectrics, and other applications in reduced dimensions. PMID:27192448

  8. Mechanical strain effects on black phosphorus nanoresonators.

    PubMed

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

    2016-01-14

    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

  9. Phosphorus chemistry in the tidal Hudson River

    SciTech Connect

    Fox, L.E. )

    1991-06-01

    A study of inorganic phosphborus in the tidal Hudson River was performed from Noverber 1988 to October 1989. Results indicate that phosphate concentrations are at or near equilibrium with a suspended solid phase consisting of amorphous ferric phosphate in amorphous ferric hydroxide. Equilibrium was observed over most of the river, over most of the year. Undersaturation was observed regularly below river mile 40 in the month of July. It represented the major deviation from equilibration. Low suspended sediment levels and dilution from sea water are believed to be responsible for undersaturation. Dissolved iron was near equilibrium with amorphous ferric hydroxide except in July. Recognition of the wide range of watersheds where phosphorus equilibrium controls phosphate concentrations suggests that the global, terrestrial flux of biologically available phosphorus may be double current estimates.

  10. 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.

  11. Controlled Sculpture of Black Phosphorus Nanoribbons.

    PubMed

    Masih Das, Paul; Danda, Gopinath; Cupo, Andrew; Parkin, William M; Liang, Liangbo; Kharche, Neerav; Ling, Xi; Huang, Shengxi; Dresselhaus, Mildred S; Meunier, Vincent; Drndić, Marija

    2016-06-28

    Black phosphorus (BP) is a highly anisotropic allotrope of phosphorus with great promise for fast functional electronics and optoelectronics. We demonstrate the controlled structural modification of few-layer BP along arbitrary crystal directions with sub-nanometer precision for the formation of few-nanometer-wide armchair and zigzag BP nanoribbons. Nanoribbons are fabricated, along with nanopores and nanogaps, using a combination of mechanical-liquid exfoliation and in situ transmission electron microscopy (TEM) and scanning TEM nanosculpting. We predict that the few-nanometer-wide BP nanoribbons realized experimentally possess clear one-dimensional quantum confinement, even when the systems are made up of a few layers. The demonstration of this procedure is key for the development of BP-based electronics, optoelectronics, thermoelectrics, and other applications in reduced dimensions.

  12. Mechanical strain effects on black phosphorus nanoresonators.

    PubMed

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

    2016-01-14

    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.

  13. In vitro PAMAM, phosphorus and viologen-phosphorus dendrimers prevent rotenone-induced cell damage.

    PubMed

    Milowska, Katarzyna; Szwed, Aleksandra; Zablocka, Maria; Caminade, Anne-Marie; Majoral, Jean-Pierre; Mignani, Serge; Gabryelak, Teresa; Bryszewska, Maria

    2014-10-20

    We have investigated whether polyamidoamine (PAMAM), phosphorus (pd) and viologen-phosphorus (vpd) dendrimers can prevent damage to embryonic mouse hippocampal cells (mHippoE-18) caused by rotenone, which is used as a pesticide, insecticide, and as a nonselective piscicide, that works by interfering with the electron transport chain in mitochondria. Several basic aspects, such as cell viability, production of reactive oxygen species and changes in mitochondrial transmembrane potential, were analyzed. mHippoE-18 cells were treated with these structurally different dendrimers at 0.1μM. A 1h incubation with dendrimers was followed by the addition of rotenone at 1μM, and a further 24h incubation. PAMAM, phosphorus and viologen-phosphorus dendrimers all increased cell viability (reduced cell death-data need to be compared with untreated controls). A lower level of reactive oxygen species and a favorable effect on mitochondrial system were found with PAMAM and viologen-phosphorus dendrimers. These results indicate reduced toxicity in the presence of dendrimers. PMID:25108046

  14. 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

    2016-02-01

    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.

  15. Peak phosphorus - peak food? The need to close the phosphorus cycle.

    PubMed

    Rhodes, Christopher J

    2013-01-01

    The peak in the world production of phosphorus has been predicted to occur in 2033, based on world reserves of rock phosphate (URR) reckoned at around 24,000 million tonnes (Mt), with around 18,000 Mt remaining. This figure was reckoned-up to 71,000 Mt, by the USGS, in 2012, but a production maximum during the present century is still highly probable. There are complex issues over what the demand will be for phosphorus in the future, as measured against a rising population (from 7 billion to over 9 billion in 2050), and a greater per capita demand for fertiliser to grow more grain, in part to feed animals and meet a rising demand for meat by a human species that is not merely more populous but more affluent. As a counterweight to this, we may expect that greater efficiencies in the use of phosphorus - including recycling from farms and of human and animal waste - will reduce the per capita demand for phosphate rock. The unseen game changer is peak oil, since phosphate is mined and recovered using machinery powered by liquid fuels refined from crude oil. Hence, peak oil and peak phosphorus might appear as conjoined twins. There is no unequivocal case that we can afford to ignore the likelihood of a supply-demand gap for phosphorus occurring sometime this century, and it would be perilous to do so.

  16. Anisotropic Thermal Conductivity of Exfoliated Black Phosphorus.

    PubMed

    Jang, Hyejin; Wood, Joshua D; Ryder, Christopher R; Hersam, Mark C; Cahill, David G

    2015-12-22

    The anisotropic thermal conductivity of passivated black phosphorus (BP), a reactive two-dimensional material with strong in-plane anisotropy, is ascertained. The room-temperature thermal conductivity for three crystalline axes of exfoliated BP is measured by time-domain thermo-reflectance. The thermal conductivity along the zigzag direction is ≈2.5 times higher than that of the armchair direction.

  17. Anisotropic Thermal Conductivity of Exfoliated Black Phosphorus.

    PubMed

    Jang, Hyejin; Wood, Joshua D; Ryder, Christopher R; Hersam, Mark C; Cahill, David G

    2015-12-22

    The anisotropic thermal conductivity of passivated black phosphorus (BP), a reactive two-dimensional material with strong in-plane anisotropy, is ascertained. The room-temperature thermal conductivity for three crystalline axes of exfoliated BP is measured by time-domain thermo-reflectance. The thermal conductivity along the zigzag direction is ≈2.5 times higher than that of the armchair direction. PMID:26516073

  18. Determination of phosphorus in cereal lipids.

    PubMed

    Kovacs, M I

    1986-05-01

    The effect of digestion methods on the determination of phosphorus in cereal lipids was reinvestigated. Samples were either digested with sulfuric acid or ashed in a muffle furnace at 600 degrees C. The standard deviation and the coefficient of variation were significantly higher for the acid-digested samples. Ashing gave more reliable results, especially when large amounts of lipid material had to be oxidized. PMID:3728960

  19. 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.

  20. Redox chemistry in the phosphorus biogeochemical cycle

    NASA Astrophysics Data System (ADS)

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

    2014-10-01

    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.

  1. 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

  2. Phosphorus removal and recovery from domestic wastewater in a novel process of enhanced biological phosphorus removal coupled with crystallization.

    PubMed

    Zou, Haiming; Wang, Yan

    2016-07-01

    A new process of enhanced biological phosphorus removal coupled with crystallization recovery of phosphorus was developed here, where the feasibility of nutrients removal and potential for phosphorus recovery from domestic wastewater was further assessed. Results showed that an excellent nutrients removal and phosphorus recovery performance was achieved, in which the averaged COD, PO4(3-)-P and NO3(-)-N removal efficiencies were 82.6%, 87.5% and 91.6%, respectively and a total of 59.3% of phosphorus was recovered as hydroxyapatite. What's more, crystallization recovery of phosphorus greatly enhanced the biological phosphorus removal efficiency. After the incorporation of the phosphorus recovery column via side-stream, the phosphorus concentration of effluent was significantly decreased ranging from 1.24mg/L to 0.85mg/L, 0.52mg/L and 0.41mg/L at the lateral flow ratios of 0, 0.1, 0.2 and 0.3, respectively. The results obtained here would be beneficial to provide a prospective alternative for phosphorus removal and recovery from wastewater.

  3. Phosphorus removal and recovery from domestic wastewater in a novel process of enhanced biological phosphorus removal coupled with crystallization.

    PubMed

    Zou, Haiming; Wang, Yan

    2016-07-01

    A new process of enhanced biological phosphorus removal coupled with crystallization recovery of phosphorus was developed here, where the feasibility of nutrients removal and potential for phosphorus recovery from domestic wastewater was further assessed. Results showed that an excellent nutrients removal and phosphorus recovery performance was achieved, in which the averaged COD, PO4(3-)-P and NO3(-)-N removal efficiencies were 82.6%, 87.5% and 91.6%, respectively and a total of 59.3% of phosphorus was recovered as hydroxyapatite. What's more, crystallization recovery of phosphorus greatly enhanced the biological phosphorus removal efficiency. After the incorporation of the phosphorus recovery column via side-stream, the phosphorus concentration of effluent was significantly decreased ranging from 1.24mg/L to 0.85mg/L, 0.52mg/L and 0.41mg/L at the lateral flow ratios of 0, 0.1, 0.2 and 0.3, respectively. The results obtained here would be beneficial to provide a prospective alternative for phosphorus removal and recovery from wastewater. PMID:27003794

  4. The phosphorus cost of agricultural intensification in the tropics.

    PubMed

    Roy, Eric D; Richards, Peter D; Martinelli, Luiz A; Coletta, Luciana Della; Lins, Silvia Rafaela Machado; Vazquez, Felipe Ferraz; Willig, Edwin; Spera, Stephanie A; VanWey, Leah K; Porder, Stephen

    2016-01-01

    Agricultural intensification in the tropics is one way to meet rising global food demand in coming decades(1,2). Although this strategy can potentially spare land from conversion to agriculture(3), it relies on large material inputs. Here we quantify one such material cost, the phosphorus fertilizer required to intensify global crop production atop phosphorus-fixing soils and achieve yields similar to productive temperate agriculture. Phosphorus-fixing soils occur mainly in the tropics, and render added phosphorus less available to crops(4,5). We estimate that intensification of the 8-12% of global croplands overlying phosphorus-fixing soils in 2005 would require 1-4 Tg P yr(-1) to overcome phosphorus fixation, equivalent to 8-25% of global inorganic phosphorus fertilizer consumption that year. This imposed phosphorus 'tax' is in addition to phosphorus added to soils and subsequently harvested in crops, and doubles (2-7 Tg P yr(-1)) for scenarios of cropland extent in 2050(6). Our estimates are informed by local-, state- and national-scale investigations in Brazil, where, more than any other tropical country, low-yielding agriculture has been replaced by intensive production. In the 11 major Brazilian agricultural states, the surplus of added inorganic fertilizer phosphorus retained by soils post harvest is strongly correlated with the fraction of cropland overlying phosphorus-fixing soils (r(2) = 0.84, p < 0.001). Our interviews with 49 farmers in the Brazilian state of Mato Grosso, which produces 8% of the world's soybeans mostly on phosphorus-fixing soils, suggest this phosphorus surplus is required even after three decades of high phosphorus inputs. Our findings in Brazil highlight the need for better understanding of long-term soil phosphorus fixation elsewhere in the tropics. Strategies beyond liming, which is currently widespread in Brazil, are needed to reduce phosphorus retention by phosphorus-fixing soils to better manage the Earth

  5. The phosphorus cost of agricultural intensification in the tropics.

    PubMed

    Roy, Eric D; Richards, Peter D; Martinelli, Luiz A; Coletta, Luciana Della; Lins, Silvia Rafaela Machado; Vazquez, Felipe Ferraz; Willig, Edwin; Spera, Stephanie A; VanWey, Leah K; Porder, Stephen

    2016-04-18

    Agricultural intensification in the tropics is one way to meet rising global food demand in coming decades(1,2). Although this strategy can potentially spare land from conversion to agriculture(3), it relies on large material inputs. Here we quantify one such material cost, the phosphorus fertilizer required to intensify global crop production atop phosphorus-fixing soils and achieve yields similar to productive temperate agriculture. Phosphorus-fixing soils occur mainly in the tropics, and render added phosphorus less available to crops(4,5). We estimate that intensification of the 8-12% of global croplands overlying phosphorus-fixing soils in 2005 would require 1-4 Tg P yr(-1) to overcome phosphorus fixation, equivalent to 8-25% of global inorganic phosphorus fertilizer consumption that year. This imposed phosphorus 'tax' is in addition to phosphorus added to soils and subsequently harvested in crops, and doubles (2-7 Tg P yr(-1)) for scenarios of cropland extent in 2050(6). Our estimates are informed by local-, state- and national-scale investigations in Brazil, where, more than any other tropical country, low-yielding agriculture has been replaced by intensive production. In the 11 major Brazilian agricultural states, the surplus of added inorganic fertilizer phosphorus retained by soils post harvest is strongly correlated with the fraction of cropland overlying phosphorus-fixing soils (r(2) = 0.84, p < 0.001). Our interviews with 49 farmers in the Brazilian state of Mato Grosso, which produces 8% of the world's soybeans mostly on phosphorus-fixing soils, suggest this phosphorus surplus is required even after three decades of high phosphorus inputs. Our findings in Brazil highlight the need for better understanding of long-term soil phosphorus fixation elsewhere in the tropics. Strategies beyond liming, which is currently widespread in Brazil, are needed to reduce phosphorus retention by phosphorus-fixing soils to better manage the Earth

  6. 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.

  7. Pigs expressing salivary phytase produce low-phosphorus manure.

    PubMed

    Golovan, S P; Meidinger, R G; Ajakaiye, A; Cottrill, M; Wiederkehr, M Z; Barney, D J; Plante, C; Pollard, J W; Fan, M Z; Hayes, M A; Laursen, J; Hjorth, J P; Hacker, R R; Phillips, J P; Forsberg, C W

    2001-08-01

    To address the problem of manure-based environmental pollution in the pork industry, we have developed the phytase transgenic pig. The saliva of these pigs contains the enzyme phytase, which allows the pigs to digest the phosphorus in phytate, the most abundant source of phosphorus in the pig diet. Without this enzyme, phytate phosphorus passes undigested into manure to become the single most important manure pollutant of pork production. We show here that salivary phytase provides essentially complete digestion of dietary phytate phosphorus, relieves the requirement for inorganic phosphate supplements, and reduces fecal phosphorus output by up to 75%. These pigs offer a unique biological approach to the management of phosphorus nutrition and environmental pollution in the pork industry. PMID:11479566

  8. Biological phosphorus removal inhibition by roxarsone in batch culture systems.

    PubMed

    Guo, Qingfeng; Liu, Li; Hu, Zhenhu; Chen, Guowei

    2013-06-01

    Roxarsone has been extensively used in the feed of animals, which is usually excreted unchanged in the manure and eventually enter into animal wastewater, challenging the biological phosphorus removal processes. Knowledge of its inhibition effect is key for guiding treatment of roxarsone-contaminated wastewater, and is unfortunately keeping unclear. We study the inhibition of roxarsone on biological phosphorus removal processes for roxarsone-contaminated wastewater treatment, in terms of the removal and rates of chemical oxygen demand (COD), phosphate. Results showed that presence of roxarsone considerably limited the COD removals, especially at roxarsone concentration exceeding 40 mg L(-1). Additionally, roxarsone inhibited both phosphorus release and uptake processes, consistent with the phosphate profiles during the biological phosphorus removal processes; whereas, roxarsone is more toxic to phosphorus uptake process, than release function. The results indicated that it is roxarsone itself, rather than the inorganic arsenics, inhibit biological phosphorus removal processes within both aerobic and anaerobic roxarsone-contaminated wastewater treatment.

  9. Semiconducting black phosphorus: synthesis, transport properties and electronic applications.

    PubMed

    Liu, Han; Du, Yuchen; Deng, Yexin; Ye, Peide D

    2015-05-01

    Phosphorus is one of the most abundant elements preserved in earth, and it comprises a fraction of ∼0.1% of the earth crust. In general, phosphorus has several allotropes, and the two most commonly seen allotropes, i.e. white and red phosphorus, are widely used in explosives and safety matches. In addition, black phosphorus, though rarely mentioned, is a layered semiconductor and has great potential in optical and electronic applications. Remarkably, this layered material can be reduced to one single atomic layer in the vertical direction owing to the van der Waals structure, and is known as phosphorene, in which the physical properties can be tremendously different from its bulk counterpart. In this review article, we trace back to the research history on black phosphorus of over 100 years from the synthesis to material properties, and extend the topic from black phosphorus to phosphorene. The physical and transport properties are highlighted for further applications in electronic and optoelectronics devices.

  10. Phosphorus, a key to life on the primitive Earth.

    PubMed

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

    1977-08-01

    The phosphorus of the primitive Earth was present as phosphates. It is strongly probably 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 turn over of the phosphorus increased rapidly. As the seas pulsated, they left the excess precipitate phosphorus as sedimentary rock in locally righ deposits on which life could thrive.

  11. Diversity enhances agricultural productivity via rhizosphere phosphorus facilitation on phosphorus-deficient soils.

    PubMed

    Li, Long; Li, Shu-Min; Sun, Jian-Hao; Zhou, Li-Li; Bao, Xing-Guo; Zhang, Hong-Gang; Zhang, Fu-Suo

    2007-07-01

    Intercropping, which grows at least two crop species on the same pieces of land at the same time, can increase grain yields greatly. Legume-grass intercrops are known to overyield because of legume nitrogen fixation. However, many agricultural soils are deficient in phosphorus. Here we show that a new mechanism of overyielding, in which phosphorus mobilized by one crop species increases the growth of a second crop species grown in alternate rows, led to large yield increases on phosphorus-deficient soils. In 4 years of field experiments, maize (Zea mays L.) overyielded by 43% and faba bean (Vicia faba L.) overyielded by 26% when intercropped on a low-phosphorus but high-nitrogen soil. We found that overyielding of maize was attributable to below-ground interactions between faba bean and maize in another field experiment. Intercropping with faba bean improved maize grain yield significantly and above-ground biomass marginally significantly, compared with maize grown with wheat, at lower rates of P fertilizer application (<75 kg of P(2)O(5) per hectare), and not significantly at high rate of P application (>112.5 kg of P(2)O(5) per hectare). By using permeable and impermeable root barriers, we found that maize overyielding resulted from its uptake of phosphorus mobilized by the acidification of the rhizosphere via faba bean root release of organic acids and protons. Faba bean overyielded because its growth season and rooting depth differed from maize. The large increase in yields from intercropping on low-phosphorus soils is likely to be especially important on heavily weathered soils.

  12. 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

  13. Soil characteristics and phosphorus level effect on phosphorus loss in runoff.

    PubMed

    Davis, Randall L; Zhang, Hailin; Schroder, Jackie Lee; Wang, Jim J; Payton, Mark E; Zazulak, Anne

    2005-01-01

    The loss of phosphorus (P) in runoff from agricultural soils may accelerate eutrophication in lakes and streams as well as degrade surface water quality. Limited soil specific data exist on the relationship between runoff P and soil P. This study investigated the relationship between runoff dissolved reactive phosphorus (DRP) and soil P for three Oklahoma benchmark soils: Richfield (fine, smectitic, mesic Aridic Argiustoll), Dennis (fine, mixed, active, thermic Aquic Argiudoll), and Kirkland (fine, mixed, superactive, thermic Udertic Paleustoll) series. These soils were selected to represent the most important agricultural soils in Oklahoma across three major land resource areas. Surface soil (0-15 cm) was collected from three designated locations, treated with diammonium phosphate (18-46-0) to establish a wide range of water-soluble phosphorus (WSP) (3.15-230 mg kg(-1)) and Mehlich-3 phosphorus (M3P) (27.8-925 mg kg(-1)). Amended soils were allowed to reach a steady state 210 d before simulated rainfall (75 mm h(-1)). Runoff was collected for 30 min from bare soil boxes (1.0 x 0.42 m and 5% slope) and analyzed for DRP and total P. Soil samples collected immediately before rainfall simulation were analyzed for the following: M3P, WSP, ammonium oxalate P saturation index (PSI(ox)), water-soluble phosphorus saturation index (PSI(WSP)), and phosphorus saturation index calculated from M3P and phosphorus sorption maxima (P(sat)). The DRP in runoff was highly related (p < 0.001) to M3P for individual soil series (r2 > 0.92). Highly significant relationships (p < 0.001) were found between runoff DRP and soil WSP for the individual soil series (r2 > 0.88). Highly significant relationships (p < 0.001) existed between DRP and different P saturation indexes. Significant differences (p < 0.05) among the slopes of the regressions for the DRP-M3P, DRP-WSP, DRP-PSI(ox), DRP-PSI(WSP), and DRP-P(sat) relationships indicate that the relationships are soil specific and phosphorus

  14. 21 CFR 558.95 - Bambermycins.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... International Feed No. Percent Deflorinated phosphate (20.5% calcium, 18.5% phosphorus) 6-01-080 42.50 Sodium... article (10 g/lb) ......... 0.60 Iron oxide 6-02-431 0.50 Magnesium sulfate (67%) 6-02-758 0.32 Selenium.... Selenium must comply with 21 CFR 573.920. Ethylenediamine dihydroiodide (EDDI) should comply with...

  15. Carbon dioxide diffusion across stomata and mesophyll and photo-biochemical processes as affected by growth CO2 and phosphorus nutrition in cotton

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Nutrients such as phosphorus availability may exert a major control over plant response to rising atmospheric carbon dioxide concentration (CO2), which is projected to double by the end of 21st century. Elevated CO2 may overcome the diffusional limitation to photosynthesis posed by stomata and mesop...

  16. Characterization of phosphorus-doped multiwalled carbon nanotubes

    NASA Astrophysics Data System (ADS)

    Larrude, D. G.; Maia da Costa, M. E. H.; Monteiro, F. H.; Pinto, A. L.; Freire, F. L.

    2012-03-01

    Phosphorus-doped multiwalled carbon nanotubes (P-MWNTs) have been successfully synthesized by spray pyrolysis methods using a solution of ferrocene and triphenylphosphine in toluene. Electron microscopy images reveal corrugated tubes with a special morphology, similar to a carbon necklace. P-MWNTs are shorter compared to undoped tubes grown in the same conditions using ferrocene and toluene as precursors. Raman spectroscopy characterization suggests the formation of more defective tubes as the phosphorus in the precursor solution was increased. X-ray photoelectron spectroscopy (XPS) revealing the chemical environment of the phosphorus atoms clearly indicates the presence of substitutional phosphorus in the nanotubes.

  17. 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.

  18. 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.

  19. 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.

  20. Phosphorus removal from domestic wastewater by Echinodorus cordifolius L.

    PubMed

    Torit, Jirawan; Siangdung, Wipawan; Thiravetyan, Paitip

    2012-01-01

    This study was to use the plants to remove phosphorus from domestic wastewater which contained high phosphorus concentration. Six higher plant species such as Crinum asiaticum L., Echinodorus cordifolius L., Spathiphyllum clevelandii Schott, Rhizophora apiculata Blume, Thalia dealbata J.fraser., Heliconia psittacorum L.f. were screened for phosphorus removal. Plants were grown in the domestic wastewater and the remaining phosphorus-phosphate concentration in the systems was determined. The results indicated that among studied plants, Echinodorus cordifolius L. was the best for phosphorus removal. Using this plant will improve the quality of domestic wastewater which contained excess phosphorus concentration and induced eutrophication. The relationship between the plants, microorganisms, and soil in the system were also investigated. In this system, adsorption by soil was the major role for phosphorus removal (71%), followed by E. cordifolius (16%), microorganisms in domestic wastewater (7%), and microorganisms in soil (6%). These results indicated the ability of E. cordifolius to remove phosphorus which was superior to that of the microorganisms in the system. Moreover, the rapid phosphorus removal was concomitant to the growth, photosynthesis activity and biomass of E. cordifolius grown in domestic wastewater. The C:N:P ratio of E. cordifolius tissue in the system indicated that elements were taken up from the wastewater. From these results, the suitability of E. cordifolius for domestic wastewater treatment was confirmed.

  1. Determination of phosphorus in natural waters: A historical review.

    PubMed

    Worsfold, Paul; McKelvie, Ian; Monbet, Phil

    2016-04-28

    The aim of this paper is to introduce a virtual special issue that reviews the development of analytical approaches to the determination of phosphorus species in natural waters. The focus is on sampling and sample treatment, analytical methods and quality assurance of the data. The export of phosphorus from anthropogenic activities (from diffuse and point sources) can result in increased primary production and eutrophication, and potentially the seasonal development of toxic algal blooms, which can significantly impact on water quality. Therefore the quantification of phosphorus species in natural waters provides important baseline data for studying aquatic phosphorus biogeochemistry, assessing ecosystem health and monitoring compliance with legislation. PMID:27046205

  2. Dietary phosphorus in bone health and quality of life.

    PubMed

    Takeda, Eiji; Yamamoto, Hironori; Yamanaka-Okumura, Hisami; Taketani, Yutaka

    2012-06-01

    Awareness of phosphorus intake is important because both phosphorus deficiency and overloading impair bone health and quality of life. Phosphorus consumption is increasing in many countries. Most dietary phosphorus is contained in protein-rich foods such as meat, milk, cheese, poultry, fish, and processed foods that contain phosphate-based additives to improve their consistency and appearance. Elevation of extracellular phosphorus levels causes endothelial dysfunction and medial calcification, which are closely associated with the development of cardiovascular disease (CVD). Long-term excessive phosphorus loading, even if it does not cause hyperphosphatemia, can be a risk factor for CVD. In epidemiological studies, higher levels of phosphorus intake have been associated with reduced blood pressure. Interestingly, when examined further, phosphorus from dairy products, but not from other sources, was usually associated with lower blood pressure. A dietary approach to phosphorus reduction is particularly important to prevent bone impairment and CVD in patients with chronic kidney disease. In order to improve bone health and quality of life in the general population, the impact of phosphorous, including in processed foods, should be considered, and measures to indicate the amount of phosphorous in food products should be implemented.

  3. 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.

  4. Numerical Simulation of Phosphorus Removal from Silicon by Induction Vacuum Refining

    NASA Astrophysics Data System (ADS)

    Zheng, Songsheng; Engh, Thorvald Abel; Tangstad, Merete; Luo, Xue-Tao

    2011-08-01

    Phosphorus can be expected to evaporate preferentially from silicon melt by induction vacuum refining (IVR). In the present study, on the assumption of phosphorus evaporating from silicon melt as gas species P and P 2, a numerical model of phosphorus removal from silicon by IVR was developed. The factors affecting phosphorus removal in decreasing order are temperature, chamber pressure, geometry of silicon melt, holding time, and original phosphorus concentration. Calculated phosphorus removal shows good agreement with the present experimental data.

  5. [Modelling nitrogen and phosphorus transfer in Potamogeton malaianus Miq. decompostion].

    PubMed

    Han, Hong-Juan; Zhai, Shui-Jing; Hu, Wei-Ping

    2010-06-01

    Potamogeton malaianus Miq. is one of the dominant species of submerged aquatic vegetations in Lake Taihu, China. The decomposition of its debris and metabolic detritus is an important part of nutrients cycling in the lake water. Nitrogen and phosphorus transfer model in P. malaianus Miq. decomposition has been set up based on an indoor P. malaianus Miq. decomposition experiment to quantitatively characterize the decomposition process. It mainly focuses on the dissolving process of inorganic nitrogen and phosphorus in P. malaianus Miq., the degradation process of its organic nitrogen and phosphorus, and the boundary's adsorbing process of nitrogen and phosphorus in water. There are eight state variables in the model, including inorganic and organic nitrogen in P. malaianus Miq., inorganic and organic phosphorus in P. malaianus Miq., total nitrogen and total phosphorus in water, and nitrogen and phosphorus adsorbed on container boundary. The model calibration showed a good accordance with the observed results of P. malaianus Miq. decomposition experiment. The dissolve rates of inorganic nitrogen and phosphorus in P. malaianus Miq. are 0.04 d(-1) and 0.06 d(-1) respectively. And the decompose rates of these two state variables are 0.005 25 d(-1) and 0.010 44 d(-1) respectively. Model outputs show that 6.7% nitrogen and 35.8% phosphorus can release from P. malaianus Miq. in the former 5 days. Phosphorus release is prior to nitrogen due to the bigger inorganic/organic ratio of phosphorus than that of nitrogen in P. malaianus Miq., Decomposition of P. malaianus Miq. could be affected by water temperature, and the affection is slight when water temperature is lower according to the model. The model also showed that P. malaianus Miq. decomposition process has influences on water quality in the former days, which can be eliminated by adsorbing process later. PMID:20698260

  6. Influence of soil phosphorus and manure on phosphorus leaching in Swedish topsoils

    Technology Transfer Automated Retrieval System (TEKTRAN)

    In Sweden, subsurface transport of phosphorus (P) represents the primary pathway of concern to surface water quality. While strong relationships have been consistently observed between P in surface runoff and soil test P, there have been mixed findings linking P in leachate with soil test P. To expl...

  7. 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...

  8. 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-β-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

  9. 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

  10. 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.

  11. 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.

  12. 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-β-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.

  13. Evidence for production and lateral transport of dissolved organic phosphorus in the eastern subtropical North Atlantic

    NASA Astrophysics Data System (ADS)

    Reynolds, Sarah; Mahaffey, Claire; Roussenov, Vassil; Williams, Richard G.

    2014-08-01

    The concentration of phosphate and dissolved organic phosphorus (DOP) is chronically low and limits phytoplankton growth in the subtropical North Atlantic relative to other ocean basins. Transport of phosphate and DOP from the productive flanks of the gyre to its interior has been hypothesized as an important phosphorus supply pathway. During a cruise in the eastern Atlantic in spring 2011, the rates of phosphate uptake, alkaline phosphatase activity (APA), and DOP production were measured in the northwest African shelf region, subtropics, and tropics. Rates of DOP production were sixfold higher in the shelf region (43 ± 41 nM d-1) relative to the subtropics (6.9 ± 4.4 nM d-1). In contrast, APA was threefold higher in the subtropics (8.0 ± 7.3 nM d-1), indicative of enhanced DOP utilization, relative to the shelf region (2.6 ± 2.1 nM d-1). Hence, observations suggest net production of DOP in the shelf region and either net consumption of DOP or a near balance in DOP production and consumption in the gyre interior. Eddy-permitting model experiments demonstrate that (i) DOP accounts for over half the total phosphorus in surface waters, (ii) DOP is transported westward from the shelf region by a combination of gyre and eddy circulations, and (iii) advected DOP supports up to 70% of the particle export over much of the subtropical gyre. Our combined observational and modeling study supports the view that the horizontal transport of DOP from the shelf region is an important mechanism supplying phosphorus to the surface subtropical North Atlantic.

  14. Effect of solids retention time and wastewater characteristics on biological phosphorus removal.

    PubMed

    Henze, M; Aspegren, H; Jansen, J la Cour; Nielsen, P H; Lee, N

    2002-01-01

    The paper deals with the effect of wastewater, plant design and operation in relation to biological nitrogen and phosphorus removal and the possibilities to model the processes. Two Bio-P pilot plants were operated for 2.5 years in parallel receiving identical wastewater. The plants had SRT of 4 and 21 days, the latter had nitrification and denitrification. The plant with 4 days SRT had much more variable biomass characteristics, than the one with the high SRT. The internal storage compounds, PHA, were affected significantly by the concentration of fatty acids or other easily degradable organics in the wastewater, and less by the plant lay-out. The phosphorus removal is mainly dependent on availability in the wastewater of fatty acids but also by the suspended solids in the effluent, which is higher in the plant with nitrification-denitrification, probably due to a higher SVI or denitrification in the settler. The addition of glucose to the influent seems to have an effect on the performance of the plants similar to that of acetic acid. In spite of great load variations over time to the pilot plants and the different operational modes, the study of population dynamics showed less significant variations with time which has importance in relation to modelling. The overall conclusion of the comparison between the two plants is that the biological phosphorus removal efficiency under practical operating conditions is affected by the SRT in the plant and the wastewater composition. Thus great care should be taken when extrapolating results from one type of plant to another. Indirectly the experiments confirm that results from lab-experiments with artificial wastewater are difficult to extrapolate through modelling to real life wastewater and conditions. The 2.5 years time series can be valuable in verification of models for Nitrogen and Enhanced Biological Phosphorus Removal. PMID:11989867

  15. Phosphorus limitation in nitrifying groundwater filters.

    PubMed

    de Vet, W W J M; van Loosdrecht, M C M; Rietveld, L C

    2012-03-15

    Phosphorus limitation has been demonstrated for heterotrophic growth in groundwater, in drinking water production and distribution systems, and for nitrification of surface water treatment at low temperatures. In this study, phosphorus limitation was tested, in the Netherlands, for nitrification of anaerobic groundwater rich in iron, ammonium and orthophosphate. The bioassay method developed by Lehtola et al. (1999) was adapted to determine the microbially available phosphorus (MAP) for nitrification. In standardized batch experiments with an enriched mixed culture inoculum, the formation of nitrite and nitrate and ATP and the growth of ammonia-oxidizing bacteria (AOB; as indicated by qPCR targeting the amoA-coding gene) were determined for MAP concentrations between 0 and 100 μg PO4-P L(-1). The nitrification and microbial growth rates were limited at under 100 μg PO4-P L(-1) and virtually stopped at under 10 μg PO4-P L(-1). In the range between 10 and 50 μg PO4-P L(-1), a linear relationship was found between MAP and the maximum nitrification rate. AOB cell growth and ATP formation were proportional to the total ammonia oxidized. Contrary to Lehtola et al. (1999), biological growth was very slow for MAP concentrations less than 25 μg PO4-P L(-1). No full conversion nor maximum cell numbers were reached within 19 days. In full-scale groundwater filters, most of the orthophosphate was removed alongside with iron. The remaining orthophosphate appeared to have only limited availability for microbial growth and activity. In some groundwater filters, nitrification was almost totally prevented by limitation of MAP. In batch experiments with filtrate water from these filters, the nitrification process could be effectively stimulated by adding phosphoric acid.

  16. 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

  17. Response of Thlaspi caerulescens to nitrogen, phosphorus and sulfur fertilisation.

    PubMed

    Catherine, Sirguey; Christophe, Schwartz; Louis, Morel Jean

    2006-01-01

    The main limiting factor for cleaning-up contaminated soils with hyperaccumulator plants is the low production of aerial biomass and the number of successive crops needed to reach the objective of remediation. The aim of this study was to contribute to the determination of a fertilisation strategy to optimise soil metal phytoextraction by Thlaspi caerulescens. A pot experiment was conducted on an agricultural soil and on a contaminated soil from the vicinity of a former Pb/Zn smelter. The nitrogen (N) treatment consisted of 4 levels (0, 11, 21.5 and 31 mg N kg(-1) dry soil (DS)) added as NH4NO3. The highest N treatment was combined with 4 levels of phosphorus (P) (0, 20, 40 and 80 mg P kg(-1) DS as KH2PO4) and sulfur (S) additions (0, 10, 20 and 30 mg S kg(-1) DS as MgSO4). The highest N fertilisation contributed significantly to enhance biomass production of T. caerulescens and to decrease the concentration of Cd and Zn in the biomass. At constant N addition, P supply did not affect metal extraction by T. caerulescens but negatively affected plant health. Sulfur supply slightly increased phytoextraction of Cd. Our results show that N and S fertilisation might interact but further investigations on the effect of such interaction on Cd extraction efficiency are needed. PMID:16924963

  18. Phosphorus removal by electric arc furnace steel slag and serpentinite.

    PubMed

    Drizo, Aleksandra; Forget, Christiane; Chapuis, Robert P; Comeau, Yves

    2006-05-01

    Electric arc furnace (EAF) steel slag and serpentinite were tested in columns either alone or mixed with limestone to determine their capacity to remove phosphorus (P) from a solution containing initially 20mg P/L (for 114 days) than 400mg P/L (for 21 days). EAF steel slag was nearly 100% efficient due to specific P adsorption onto metal hydroxides and precipitation of hydroxyapatite. Serpentinite also showed a good performance that decreased with time, adsorption appearing to be the dominant mechanism for P removal. Mixing limestone with these two materials did not improve their performance and in the case of serpentinite, it actually even decreased it. In 114 days of experimentation, serpentinite alone and the mixture of serpentinite and limestone removed 1.0mg P/g while in 180 days of experimentation, EAF steel slag and the mixture of slag and limestone removed an average of 2.2mg P/g, without attaining their maximum P removal potential. The void hydraulic retention time (HRTv) was a key factor for growing hydroxyapatite crystals and had a significant effect on P removal efficiency by EAF steel slag. A temporary increase in HRTv caused by clogging resulted in an increase in EAF steel slag efficiency (from 80% to almost 100%) towards the end of investigation. Results from this study indicate that the use of EAF steel slag in constructed wetlands or filter beds is a promising solution for P removal via adsorption and precipitation mechanisms.

  19. Excitons in atomically thin black phosphorus

    NASA Astrophysics Data System (ADS)

    Surrente, A.; Mitioglu, A. A.; Galkowski, K.; Tabis, W.; Maude, D. K.; Plochocka, P.

    2016-03-01

    Raman scattering and photoluminescence spectroscopy are used to investigate the optical properties of single layer black phosphorus obtained by mechanical exfoliation of bulk crystals under an argon atmosphere. The Raman spectroscopy, performed in situ on the same flake as the photoluminescence measurements, demonstrates the single layer character of the investigated samples. The emission spectra, dominated by excitonic effects, display the expected in-plane anisotropy. The emission energy depends on the type of substrate on which the flake is placed due to the different dielectric screening. Finally, the blueshift of the emission with increasing temperature is well described using a two-oscillator model for the temperature dependence of the band gap.

  20. Molecular phosphorus ion source for semiconductor technologya)

    NASA Astrophysics Data System (ADS)

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

    2012-02-01

    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 P4+ 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 P4+ ion beam current greater than 30% of the total beam current.

  1. 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.

  2. Enhanced biological phosphorus removal employing EDTA disodium

    SciTech Connect

    Bojinova, D.; Velkova, R.

    1996-12-31

    The biological phosphorus removal is a promising alternative to the conventional chemical technologies for processing of phosphate raw materials. The object of this study was the effect of EDTA disodium on the biotreatment of tunisian phosphorite with the strain of Aspergillus niger. The incubation was carried out in two nutritive mediums, with different phosphate content. The experimental results showed that the additives of EDTA disodium in the nutritive medium increased the rate of extraction of P{sub 2}O{sub 5} and shortened significantly the time for biological leaching. 5 refs., 3 figs., 2 tabs.

  3. 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.

  4. Phosphorus donors in highly strained silicon.

    PubMed

    Huebl, Hans; Stegner, Andre R; Stutzmann, Martin; Brandt, Martin S; Vogg, Guenther; Bensch, Frank; Rauls, Eva; Gerstmann, Uwe

    2006-10-20

    The hyperfine interaction of phosphorus donors in fully strained Si thin films grown on virtual Si(1-x)Ge(x) substrates with x< or =0.3 is determined via electrically detected magnetic resonance. For highly strained epilayers, hyperfine interactions as low as 0.8 mT are observed, significantly below the limit predicted by valley repopulation. Within a Green's function approach, density functional theory shows that the additional reduction is caused by the volume increase of the unit cell and a relaxation of the Si ligands of the donor.

  5. 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

  6. Phosphorus leaching in relation to soil type and soil phosphorus content.

    PubMed

    Djodjic, Faruk; Börling, Katarina; Bergström, Lars

    2004-01-01

    Phosphorus losses from arable soils contribute to eutrophication of freshwater systems. In addition to losses through surface runoff, leaching has lately gained increased attention as an important P transport pathway. Increased P levels in arable soils have highlighted the necessity of establishing a relationship between actual P leaching and soil P levels. In this study, we measured leaching of total phosphorus (TP) and dissolved reactive phosphorus (DRP) during three years in undisturbed soil columns of five soils. The soils were collected at sites, established between 1957 and 1966, included in a long-term Swedish fertility experiment with four P fertilization levels at each site. Total P losses varied between 0.03 and 1.09 kg ha(-1) yr(-1), but no general correlation could be found between P concentrations and soil test P (Olsen P and phosphorus content in ammonium lactate extract [P-AL]) or P sorption indices (single-point phosphorus sorption index [PSI] and P sorption saturation) of the topsoil. Instead, water transport mechanism through the soil and subsoil properties seemed to be more important for P leaching than soil test P value in the topsoil. In one soil, where preferential flow was the dominant water transport pathway, water and P bypassed the high sorption capacity of the subsoil, resulting in high losses. On the other hand, P leaching from some soils was low in spite of high P applications due to high P sorption capacity in the subsoil. Therefore, site-specific factors may serve as indicators for P leaching losses, but a single, general indicator for all soil types was not found in this study. PMID:15074820

  7. 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.

  8. Dietary phosphorus is associated with greater left ventricular mass.

    PubMed

    Yamamoto, Kalani T; Robinson-Cohen, Cassianne; de Oliveira, Marcia C; Kostina, Alina; Nettleton, Jennifer A; Ix, Joachim H; Nguyen, Ha; Eng, John; Lima, Joao A C; Siscovick, David S; Weiss, Noel S; Kestenbaum, Bryan

    2013-04-01

    Dietary phosphorus consumption has risen steadily in the United States. Oral phosphorus loading alters key regulatory hormones and impairs vascular endothelial function, which may lead to an increase in left ventricular mass (LVM). We investigated the association of dietary phosphorus with LVM in 4494 participants from the Multi-Ethnic Study of Atherosclerosis, a community-based study of individuals who were free of known cardiovascular disease. The intake of dietary phosphorus was estimated using a 120-item food frequency questionnaire and the LVM was measured using magnetic resonance imaging. Regression models were used to determine associations of estimated dietary phosphorus with LVM and left ventricular hypertrophy (LVH). Mean estimated dietary phosphorus intake was 1167 mg/day in men and 1017 mg/day in women. After adjustment for demographics, dietary sodium, total calories, lifestyle factors, comorbidities, and established LVH risk factors, each quintile increase in the estimated dietary phosphate intake was associated with an estimated 1.1 g greater LVM. The highest gender-specific dietary phosphorus quintile was associated with an estimated 6.1 g greater LVM compared with the lowest quintile. Higher dietary phosphorus intake was associated with greater odds of LVH among women, but not men. These associations require confirmation in other studies.

  9. Phytate and phosphorus movements in the digestive tract of horses.

    PubMed

    Matsui, T; Murakami, Y; Yano, H; Fujikawa, H; Osawa, T; Asai, Y

    1999-07-01

    This experiment was conducted to study phytate degradation and the effect of dietary phytate level on phosphorus absorption in the gastrointestinal tract of horses. Six Thoroughbred horses were fed diets containing low-phytate diet or high-phytate diet for 5 days. The diets were supplemented with Cr2O3 as an unabsorbable marker. The horses were killed 3 h after the last feeding and digesta in some segments of the intestine were collected. In both dietary groups, the daily passage of phytate phosphorus was decreased in the upper small intestine and in the lower large intestine. The daily passage of phytate phosphorus in the lower large intestine did not differ between these groups. Although the passage of total phosphorus increased in the upper small intestine and in the upper large intestine of both groups, its passage decreased in the lower large intestine. These results suggest that phytate phosphorus is degraded in the upper small intestine and in the lower large intestine of both groups. Phosphorus is suggested to be mainly absorbed in the lower large intestine. Therefore, phytate phosphorus is considered to be easily absorbed in horses because the major site of phosphorus is the lower large intestine where most of phytate is already degraded.

  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. The total phosphorus budget of a peat-covered catchment

    NASA Astrophysics Data System (ADS)

    Worrall, Fred; Moody, Catherine S.; Clay, Gareth D.; Burt, Tim P.; Rose, Rob

    2016-07-01

    Although many studies have considered the carbon or greenhouse gas budgets of peat ecosystems, only a few have considered the nutrient budget of peat soils, and this, in turn, has limited the ability of studies to consider the impact of changes in climate and atmospheric deposition on the phosphorus budget of a peat soil. This study considered the total phosphorus (P) budget of an upland peat-covered catchment over the period 1993 to 2012. The study has shown (i) total atmospheric deposition of phosphorus varied from 62 to 175 kg P/km2/yr; (ii) the carbon:phosphorus ratio of the peat profile declines significantly from values in the litter layer (C:P = 1326) to approximately constant at 30 cm depth (C:P = 4240); (iii) the total fluvial flux of phosphorus varied from 49 to 111 kg P/km2/yr, of which between 45 and 77% was dissolved P; and (iv) the total phosphorus sink varied from -5.6 to +71.7 kg P/km2/yr with a median of +29.4 kg P/km2/yr, which is within the range of the estimated long-term accumulation rate of phosphorus in the peat profile of between 3 and 32 kg P/km2/yr. The phosphorus budget of the peat ecosystem relies on rapid recycling near the soil surface, and this means that any vegetation management may critically deprive the ecosystem of this nutrient.

  12. 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...

  13. 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

  14. 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 ...

  15. Plant based phosphorus recovery from wastewater via algae and macrophytes.

    PubMed

    Shilton, Andrew N; Powell, Nicola; Guieysse, Benoit

    2012-12-01

    At present, resource recovery by irrigation of wastewater to plants is usually driven by the value of the water resource rather than phosphorus recovery. Expanded irrigation for increased phosphorus recovery may be expected as the scarcity and price of phosphorus increases, but providing the necessary treatment, storage and conveyance comes at significant expense. An alternative to taking the wastewater to the plants is instead to take the plants to the wastewater. Algal ponds and macrophyte wetlands are already in widespread use for wastewater treatment and if harvested, would require less than one-tenth of the area to recover phosphorus compared to terrestrial crops/pastures. This area could be further decreased if the phosphorus content of the macrophytes and algae biomass was tripled from 1% to 3% via luxury uptake. While this and many other opportunities for plant based recovery of phosphorus exist, e.g. offshore cultivation, much of this technology development is still in its infancy. Research that enhances our understanding of how to maximise phosphorus uptake and harvest yields; and further add value to the biomass for reuse would see the recovery of phosphorus via plants become an important solution in the future.

  16. Plant based phosphorus recovery from wastewater via algae and macrophytes.

    PubMed

    Shilton, Andrew N; Powell, Nicola; Guieysse, Benoit

    2012-12-01

    At present, resource recovery by irrigation of wastewater to plants is usually driven by the value of the water resource rather than phosphorus recovery. Expanded irrigation for increased phosphorus recovery may be expected as the scarcity and price of phosphorus increases, but providing the necessary treatment, storage and conveyance comes at significant expense. An alternative to taking the wastewater to the plants is instead to take the plants to the wastewater. Algal ponds and macrophyte wetlands are already in widespread use for wastewater treatment and if harvested, would require less than one-tenth of the area to recover phosphorus compared to terrestrial crops/pastures. This area could be further decreased if the phosphorus content of the macrophytes and algae biomass was tripled from 1% to 3% via luxury uptake. While this and many other opportunities for plant based recovery of phosphorus exist, e.g. offshore cultivation, much of this technology development is still in its infancy. Research that enhances our understanding of how to maximise phosphorus uptake and harvest yields; and further add value to the biomass for reuse would see the recovery of phosphorus via plants become an important solution in the future. PMID:22889679

  17. Phosphorus run-off assessment in a watershed.

    PubMed

    Chebud, Yirgalem; Naja, Ghinwa M; Rivero, Rosanna

    2011-01-01

    The Watershed Assessment Model was used to simulate the runoff volume, peak flows, and non-point source phosphorus loadings from the 5870 km(2) Lake Okeechobee watershed as a case study. The results were compared to on-site monitoring to verify the accuracy of the method and to estimate the observed/simulated error. In 2008, the total simulated phosphorus contribution was 9634, 6524 and 3908 kg (P) y(-1) from sod farms, citrus farms and row crop farmlands, respectively. Although the dairies represent less than 1% of the total area of Kissimmee basin, the simulated P load from the dairies (9283 kg (P) y(-1) in 2008) made up 5.4% of the total P load during 2008. On average, the modeled P yield rates from dairies, sod farms and row crop farmlands are 3.85, 2.01 and 0.86 kg (P) ha(-1) y(-1), respectively. The maximum sediment simulated phosphorus yield rate is about 2 kg (P) ha(-1) and the particulate simulated phosphorus contribution from urban, improved pastures and dairies to the total phosphorus load was estimated at 9%, 3.5%, and 1%, respectively. Land parcels with P oversaturated soil as well as the land parcels with high phosphorus assimilation and high total phosphorus contribution were located. The most critical sub-basin was identified for eventual targeting by enforced agricultural best management practices. Phosphorus load, including stream assimilation, incoming to Lake Okeechobee from two selected dairies was also determined.

  18. 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

  19. Phosphorus Removal By Silage Corn In Southern Idaho

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Corn silage is the predominant crop in Idaho used for recovering phosphorus (P) that has accumulated in soils from dairy manure applications. However, little is known about how much phosphorus and other nutrients are being recovered under Idaho conditions. The objective of the study is to estimate p...

  20. [Mapping and cloning of low phosphorus tolerance genes in soybeans].

    PubMed

    Dan, Zhang; Haina, Song; Hao, Cheng; Deyue, Yu

    2015-04-01

    Soybean is a major source of edible oil and phytoprotein. Low phosphorus available in soil is an important factor limiting the current soybean production. Effective ways to solve the problem include identification of germplasms and genes tolerant to low-phosphorus stress, and cultivation of soybean varieties with high phosphorus efficiency. Recently many researches have been carrying out investigations to map and clone genes related to phosphorus efficiency in soybeans. However, due to the complexity of the soybean genome and little knowledge of functional genes, it has been difficult to understand the mechanism of soybean tolerance to low phosphorus. Although quantitative trait locus (QTL) mapping related to low phosphorus tolerance has made some progress, it remains elusive to obtain accurate candidate genes for molecular breeding applications, due to the limited accuracy of QTL. Even for the cloned soybean low phosphorus tolerance genes, the molecular mechanisms are largely unknown, further limiting the application to breeding. In this review, we summarize the progresses on mapping, cloning and functional characterization of soybean low phosphorus tolerance genes.

  1. Phosphorus as a limiting factor on sustainable greywater irrigation.

    PubMed

    Turner, Ryan D R; Will, Geoffrey D; Dawes, Les A; Gardner, Edward A; Lyons, David J

    2013-07-01

    Water reuse through greywater irrigation has been adopted worldwide and has been proposed as a potential sustainable solution to increased water demands. Despite widespread adoption, there is limited domestic knowledge of greywater reuse. There is no pressure to produce low-level phosphorus products and current guidelines and legislation, such as those in Australia, may be inadequate due to the lack of long-term data to provide a sound scientific basis. Research has clearly identified phosphorus as a potential environmental risk to waterways from many forms of irrigation. To assess the sustainability of greywater irrigation, this study compared four residential lots that had been irrigated with greywater for four years and adjacent non-irrigated lots that acted as controls. Each lot was monitored for the volume of greywater applied and selected physic-chemical water quality parameters and soil chemistry profiles were analysed. The non-irrigated soil profiles showed low levels of phosphorus and were used as controls. The Mechlich3 Phosphorus ratio (M3PSR) and Phosphate Environmental Risk Index (PERI) were used to determine the environmental risk of phosphorus leaching from the irrigated soils. Soil phosphorus concentrations were compared to theoretical greywater irrigation loadings. The measured phosphorus soil concentrations and the estimated greywater loadings were of similar magnitude. Sustainable greywater reuse is possible; however incorrect use and/or lack of understanding of how household products affect greywater can result in phosphorus posing a significant risk to the environment.

  2. 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.

  3. Phosphorus runoff from Coastal Plain forest soil in Louisiana

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Although not a common practice, poultry litter (PL) may be used for forest fertilization. Despite usually low soil phosphorus (P) and runoff under forest, repeated or high rates of PL application may cause appreciable P loss. Phosphorus in natural runoff under loblolly pine (Pinus taeda L.) fertiliz...

  4. [Characterization of phosphorus forms in different organic materials].

    PubMed

    Deng, Jia; Hu, Meng-Kun; Zhao, Xiu-Lan; Ni, Jiu-Pai; Xie, De-Ti

    2015-03-01

    The existing forms of phosphorus in seven organic waste materials including biogas residues of swine manure (ZZ), biogas residues of cattle manure (NZ), compost of cattle manure and corn straw (NJD), compost of sewage sludge (WD) and compost of rural daily garbage (NSLD) were characterized according to phosphorus fractionation procedures developed by DOU et al. The result showed that there was a great difference in the total phosphorus (TP) and the total phosphorus of various forms (P(t)) among different organic materials. ZZ had the highest content of TP with the value of 23.59 g x kg(-1); while NZ had the lowest TP content with the value of 3.61 g x kg(-1). The contents and proportions of phosphorus fractions in ZZ, NZ, NJD and WD followed the order of HCl-P > Residues-P > NaHCO3-P > NaOH-P > H2O-P, while followed the order of HC1-P > Residues-P > H2O-P > NaHCO3-P > NaOH-P in the three NSLDs. The proportion of HCl-P in the total fractionated phosphorus (P(tt)) in seven organic materials ranged from 47.75% to 84.96%, which indicated that most of P in organic materials existed in the forms that were easier to be extracted by strong extracting agents like HCl, which was difficult to be absorbed by plants. The inorganic phosphorus accounted for 79.72% -94.76% of the total phosphorus in the organic materials. Of all the phosphorus forms, the NaHCO3-P had the highest inorganic phosphorus fractions, but the inorganic phosphorus was mainly distributed in HCl-P. The organic phosphorus was mainly distributed in HCl-P and Residues-P. In addition, the higher proportions of inorganic phosphorus in NJD than those of NZ demonstrated that the composting process was benefit for the mineralization of organic phosphorus in organic materials and thus improving its availability.

  5. Organ-specific phosphorus-allocation patterns and transcript profiles linked to phosphorus efficiency in two contrasting wheat genotypes.

    PubMed

    Aziz, Tariq; Finnegan, Patrick M; Lambers, Hans; Jost, Ricarda

    2014-04-01

    Recent studies have identified genotypic variation in phosphorus (P) efficiency, but rarely have the underlying mechanisms been described at the molecular level. We demonstrate that the highly P-efficient wheat (Triticum aestivum L.) cultivar Chinese 80-55 maintains higher inorganic phosphate (Pi ) concentrations in all organs upon Pi withdrawal in combination with higher Pi acquisition in the presence of Pi when compared with the less-efficient cultivar Machete. These findings correlated with differential organ-specific expression of Pi transporters TaPHT1;2, TaPHT1;5, TaPHT1;8, TaPHT2;1 and H(+) -ATPase TaHa1. Observed transcript level differences between the cultivars suggest that higher de novo phospholipid biosynthetic activities in Pi -limited elongating basal leaf sections are another crucial adaptation in Chinese 80-55 for sustaining growth upon Pi withdrawal. These activities may be supported through enhanced breakdown of starch in Chinese 80-55 stems as suggested by higher TaGPho1 transcript levels. Chinese 80-55 fine roots on the other hand show strong suppression of transcripts involved in glycolysis, transcriptional regulation and ribosomal activities. Our work reveals major differences in the way the two contrasting cultivars allocate Pi and organic P compounds between source and sink tissues and in the acclimation of their metabolism to changes in Pi availability.

  6. Localized Surface Plasmons in Nanostructured Monolayer Black Phosphorus.

    PubMed

    Liu, Zizhuo; Aydin, Koray

    2016-06-01

    Plasmonic materials provide electric-field localization and light confinement at subwavelength scales due to strong light-matter interaction around resonance frequencies. Graphene has been recently studied as an atomically thin plasmonic material for infrared and terahertz wavelengths. Here, we theoretically investigate localized surface plasmon resonances (LSPR) in a monolayer, nanostructured black phosphorus (BP). Using finite-difference time-domain simulations, we demonstrate LSPRs at mid-infrared and far-infrared wavelength regime in BP nanoribbon and nanopatch arrays. Because of strong anisotropic in-plane properties of black phosphorus emerging from its puckered crystal structure, black phosphorus nanostructures provide polarization dependent, anisotropic plasmonic response. Electromagnetic simulations reveal that monolayer black phosphorus nanostructures can strongly confine infrared radiation in an atomically thin material. Black phosphorus can find use as a highly anisotropic plasmonic devices. PMID:27152653

  7. Calcium and phosphorus change of the Apollo 17 crew members.

    PubMed

    Rambaut, P C; Leach, C S; Johnson, P C

    1975-01-01

    In association with the 12.6-day lunar flight of Apollo 17, calcium and phosphorus intake and excretion were determined for the crew members before and during the mission. The study showed increased urinary and fecal phosphorus and increased fecal calcium during weightlessness. The calculated mean calcium "loss" for the three crew members was 0.2 percent of estimated total body calcium and phosphorus "loss" was 0.7 percent of estimated total body phosphorus. The ratio of phosphorus lost compared to calcium indicated a reduction in both bone and soft tissue. These changes may be attributed not only to the hypogravia of the lunar and circumlunar environment, but possibly also to disturbances in gastrointestinal absorption.

  8. Enhanced phosphorus removal by microbial-collaborating sponge iron.

    PubMed

    Wang, Ya'e; Li, Jie; Zhai, Siyuan; Wei, Zhiyong; Feng, Juanjuan

    2015-01-01

    The collaborative and mutually reinforcing phosphorus removal in domestic wastewater in a sponge iron and microorganisms system was studied through a laboratory and a pilot scale experiment. The results showed that the total phosphorus concentration of the effluent of less than 0.5 mg/L could be achieved. The results also support that the biochemical reaction accelerated the iron electrochemical corrosion. As a driving force, iron bacteria strengthened the chemical oxidation of Fe(II) to Fe(III). The chemical precipitation of Fe(III) is the main form of phosphorus removal. In addition, there exists adsorption phosphorus removal by phosphate-accumulating organisms. The mechanism of the enhanced phosphorus removal by microbial-collaborating sponge iron was thus proposed.

  9. Treatment of phosphorus waste water using crystallization method.

    PubMed

    Bian, Dejun; Ai, Shengshu; Liu, Jing; Zuo, Yan; Tian, Xi

    2011-06-01

    Phosphorus is the restrictive factor of water eutrophication and phosphorus removal is the key point to control this phenomenon. It's also important to recover phosphorus resource from wastewater. Crystallization method was used to treat and recycle high concentration phosphorus wastewater, the selection of organic solvent, influence of volume ratio of organic solvent and wastewater, precipitation time and stirring speed on the production of crystal and its structure was investigated. Experimental results indicate that, with ethanol as extractant, under the condition of volume ratio of ethanol to wastewater being 1.5:1 and stirring speed about 200 r/min, crystal precipitated fast with fine crystal shape and purity, phosphorus removal efficiency more than 85% was obtained.

  10. Soil phosphorus and the ecology of lowland tropical forests

    NASA Astrophysics Data System (ADS)

    Turner, Ben

    2016-04-01

    In this presentation I will explore the extent to which phosphorus influences the productivity, diversity, and distribution of plant species in tropical forests. I will highlight the range of soils that occur in tropical forests and will argue that pedogenesis and associated phosphorus depletion is a primary driver of forest diversity over long timescales. I will draw on data from a regional-scale network of forest dynamics plots in Panama to show that tree species distributions are determined predominantly as a function of dry season intensity and soil phosphorus availability, and will suggest potential mechanistic explanations for this pattern in relation to phosphorus acquisition. Finally, I will present observational and experimental evidence from Panama to show how phosphorus, nitrogen, and potassium, limit plant productivity and microbial communities on strongly-weathered soils in the lowland tropics.

  11. Black phosphorus nanoelectromechanical resonators vibrating at very high frequencies.

    PubMed

    Wang, Zenghui; Jia, Hao; Zheng, Xuqian; Yang, Rui; Wang, Zefang; Ye, G J; Chen, X H; Shan, Jie; Feng, Philip X-L

    2015-01-21

    We report on the experimental demonstration of a new type of nanoelectromechanical resonator based on black phosphorus crystals. Facilitated by a highly efficient dry transfer technique, crystalline black phosphorus flakes are harnessed to enable drumhead resonators vibrating at high and very high frequencies (HF and VHF bands, up to ∼100 MHz). We investigate the resonant vibrational responses from the black phosphorus crystals by devising both electrical and optical excitation schemes, in addition to measuring the undriven thermomechanical motions in these suspended nanostructures. Flakes with thicknesses from ∼200 nm down to ∼20 nm clearly exhibit elastic characteristics transitioning from the plate to the membrane regime. Both frequency- and time-domain measurements of the nanomechanical resonances show that very thin black phosphorus crystals hold interesting potential for moveable and vibratory devices and for semiconductor transducers where high-speed mechanical motions could be coupled to the attractive electronic and optoelectronic properties of black phosphorus.

  12. 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.

  13. Localized Surface Plasmons in Nanostructured Monolayer Black Phosphorus.

    PubMed

    Liu, Zizhuo; Aydin, Koray

    2016-06-01

    Plasmonic materials provide electric-field localization and light confinement at subwavelength scales due to strong light-matter interaction around resonance frequencies. Graphene has been recently studied as an atomically thin plasmonic material for infrared and terahertz wavelengths. Here, we theoretically investigate localized surface plasmon resonances (LSPR) in a monolayer, nanostructured black phosphorus (BP). Using finite-difference time-domain simulations, we demonstrate LSPRs at mid-infrared and far-infrared wavelength regime in BP nanoribbon and nanopatch arrays. Because of strong anisotropic in-plane properties of black phosphorus emerging from its puckered crystal structure, black phosphorus nanostructures provide polarization dependent, anisotropic plasmonic response. Electromagnetic simulations reveal that monolayer black phosphorus nanostructures can strongly confine infrared radiation in an atomically thin material. Black phosphorus can find use as a highly anisotropic plasmonic devices.

  14. 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.

  15. 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.

  16. Phosphorus in the fulvate fraction of soil organic matter

    NASA Astrophysics Data System (ADS)

    Makarov, M. I.; Leoshkina, N. A.

    2009-03-01

    The concentration of phosphorus in preparations of fulvic acids separated from soils according to a modified IHSS method varies from 0.03 to 0.23%; it is considerably lower than the concentration of phosphorus in preparations of humic acids (0.15-1.54%). A predominant part (>90%) of phosphorus-containing compounds in the fulvates is not sorbed on the polymethylmethacrylic resin Supelite DAX-8 used for the isolation of fulvic acids. These compounds are highly hydrophilic, and their sorption on the polystyrene-divinylbenzene resin XAD-4 used for the isolation of nonspecific organic compounds with a lower molecular weight and higher hydrophily does not exceed 20%. The results of the study attest to the quantitative indefiniteness of the notion of “phosphorus of fulvic acids” and cause doubt upon a hypothesis about an important role of fulvic acids in the migration of phosphorus compounds in soils and landscapes.

  17. Black phosphorus nanoelectromechanical resonators vibrating at very high frequencies.

    PubMed

    Wang, Zenghui; Jia, Hao; Zheng, Xuqian; Yang, Rui; Wang, Zefang; Ye, G J; Chen, X H; Shan, Jie; Feng, Philip X-L

    2015-01-21

    We report on the experimental demonstration of a new type of nanoelectromechanical resonator based on black phosphorus crystals. Facilitated by a highly efficient dry transfer technique, crystalline black phosphorus flakes are harnessed to enable drumhead resonators vibrating at high and very high frequencies (HF and VHF bands, up to ∼100 MHz). We investigate the resonant vibrational responses from the black phosphorus crystals by devising both electrical and optical excitation schemes, in addition to measuring the undriven thermomechanical motions in these suspended nanostructures. Flakes with thicknesses from ∼200 nm down to ∼20 nm clearly exhibit elastic characteristics transitioning from the plate to the membrane regime. Both frequency- and time-domain measurements of the nanomechanical resonances show that very thin black phosphorus crystals hold interesting potential for moveable and vibratory devices and for semiconductor transducers where high-speed mechanical motions could be coupled to the attractive electronic and optoelectronic properties of black phosphorus. PMID:25385657

  18. Controlled Sculpture of Black Phosphorus Nanoribbons

    DOE PAGES

    Masih Das, Paul; Danda, Gopinath; Cupo, Andrew; Parkin, William M.; Liang, Liangbo; Kharche, Neerav; Ling, Xi; Huang, Shengxi; Dresselhaus, Mildred S.; Meunier, Vincent; et al

    2016-05-18

    Black phosphorus (BP) is a highly anisotropic allotrope of phosphorus with high promise for fast functional electronics and optoelectronics. We demonstrate that high-resolution and controlled structural modification of few-layer BP along arbitrary crystal direction can be achieved with nanometer-scale precision on a few-minute timescales leading to the formation of sub-nm wide armchair and zigzag BP nanoribbons. The nanoribbons are assembled, along with nanopores and nanogaps, using a combination of mechanical-liquid exfoliation and in situ transmission electron microscope (TEM) and scanning TEM nanosculpting. Here we report time-dependent structural properties of the one-dimensional systems under electron irradiation and probe their oxidation propertiesmore » with electron energy-loss spectroscopy (EELS). Finally, we demonstrate the use of STEM to controllably narrow and thin the nanoribbons until they break into nanogaps. The observations are rationalized using density functional theory for transition state calculations and electronic band-structure evolution for the various stages of the narrowing procedure. In particular, we predict that the sub- and few-nm wide BP nanoribbons realized experimentally possess clear one-dimensional quantum confinement, even when the systems are made up of a few layers. We find the demonstration of this procedure is key for the development of BP-based electronic, optoelectronic, thermoelectric, and other applications in reduced dimensions.« less

  19. Calcium effect on enhanced biological phosphorus removal.

    PubMed

    Barat, R; Montoya, T; Borras, L; Seco, A; Ferrer, J

    2006-01-01

    The role of calcium (Ca) in enhanced biological phosphorus removal and its possible implications on the metabolic pathway have been studied. The experience has been carried out in an SBR under anaerobic-aerobic conditions for biological phosphorus removal during 8 months. The variations of influent Ca concentration showed a clear influence on the EBPR process, detecting significant changes in Y(PO4). These Y(PO4) variations were not due to influent P/COD ratio, pH, denitrification and calcium phosphate formation. The Y(PO4) has been found to be highly dependent on the Ca concentration, increasing as Ca concentration decreases. The results suggest that high Ca concentrations produce "inert" granules of polyphosphate with Ca as a counterion that are not involved in P release and uptake. Furthermore, microbiological observations confirmed that appreciable changes in PAO and GAO populations were not observed. This behaviour could suggest a change in the bacterial metabolic pathway, with prevailing polyphosphate-accumulating metabolism (PAM) at low influent Ca concentration and glycogen-accumulating metabolism (GAM) at high concentration.

  20. Phosphorus Accumulating Organisms and Biogeochemical Hotspots

    NASA Astrophysics Data System (ADS)

    Archibald, J.; Walter, M. T.

    2008-12-01

    Despite extensive research, many of the processes that control phosphorus (P) movement from agricultural fields to streams and lakes are not well understood. This limits our ability to develop management strategies that will mediate P contamination of freshwater ecosystems and subsequent eutrophication. Recent advances in molecular microbiology have prompted a paradigm shift in wastewater treatment that recognizes and exploits the ways specific microbial processes influence P solubility. Central to this enhanced biological phosphorus removal in wastewater treatment plants is a relatively recently discovered microorganism, Candidatus accumulibacter, which takes-up P and stores it internally as polyphosphate under alternating aerobic and anaerobic conditions. Within the past few months we have discovered this organism in the natural environment and its role in P biogeochemistry is unclear. We speculate that it may function similarly in variable source areas, which experience cycles of saturation and desaturation, as it does in the anaerobic- aerobic cycles in a wastewater treatment plant. If so, there may be potential opportunities to realize similarly new perspectives and advancements in the watershed context as have been seen in wastewater technologies. Here we present some of our preliminary findings.

  1. Soil organic phosphorus characterisation on a glacial chronosequence (Damma, Switzerland)

    NASA Astrophysics Data System (ADS)

    Jarosch, Klaus A.; Requejo, María I.; Bünemann, Else K.

    2015-04-01

    Soil organic phosphorus (P) may play a significant role in ecosystem P dynamics, yet, little is known about the development of different organic P classes over time. According to the commonly accepted model, relative proportions of organic P are expected to increase quickly after the commencement of soil development, subsequently remaining relatively stable over time. We tested this hypothesis on a young soil chronosequence in the Damma glacier forefield (Switzerland), where we examined the development of different organic P classes over time. In detail, we hypothesized that organic P compounds resistant against broadly active phosphatase-enzymes would increase with soil age. Soil samples (0-5 cm) were taken on 21 sites with 6 to 136 years of soil development. Using enzyme addition assays to soil extracts (0.25 M NaOH / 0.05 M EDTA), four organic P classes were detected: a) Monoester-like P (organic P hydrolysed by an acid phosphatase), b) DNA-like P (organic P hydrolysed by a nuclease in combination with an acid phosphatase, minus monoester-like P), c) Inositol Phosphate-like P (organic P hydrolysed by a phytase, minus monoester like P) and d) Enzyme stable P (difference between total extracted organic P and the three enzyme labile P classes a, b and c). NaOH-EDTA extractable inorganic and organic P increased with soil age from 4.2 and 5.2 mg kg-1 at the youngest sites to 23.9 and 64.5 mg kg-1 at the oldest sites, respectively. On all sites, more organic than inorganic P was extracted. We observed a strong linear relationship between organic and inorganic P along the chronosequence. Between 60 and 100% of extractable organic P was hydrolysed by the added enzymes, without a clear trend with respect to soil age. On most sites, Inositol phosphate-like P was the most prominent organic P class (1.8-24.3 mg kg-1). However, on some sites higher amounts of monoester-like P were detected (0.4-23.4 mg kg-1). DNA-like P ranged from nil to 12.9 mg kg-1. Thus, we observed a

  2. Nitrogen and phosphorus intake by phytoplankton in the Xiamen Bay

    NASA Astrophysics Data System (ADS)

    Lin, Cai; Li, Hui; He, Qing; Xu, Kuncan; Wu, Shengsan; Zhang, Yuanbiao; Chen, Jinmin; Chen, Baohong; Lin, Libin; Lu, Meiluan; Chen, Weifen; Tang, Rongkun; Ji, Weidong

    2010-01-01

    This paper describes a time series experiment examining the nitrogen and phosphorus intake of natural phytoplankton communities by a microcosms approach. Seawater samples containing natural phytoplankton communities were collected from waters around Baozhu Islet in inner Xiamen Bay and around Qingyu Islet in the outer bay. The goal was to elucidate the relationship between phytoplankton population enhancement, the biological removal of nitrogen and phosphorus from the seawater, and the phytoplankton nitrogen and phosphorus intake ratio based on nitrogen and phosphorus removal from seawater by phytoplankton, to provide a basis for detecting prewarning conditions for red tide and the assessment of red tide events. Two key results were obtained: 1. During the experiment, the nitrogen and phosphorus seawater concentrations in samples from these two sites were negatively and closely correlated to the logarithm of the phytoplankton cell concentration and to the value of the apparent oxygen increment. The ratio of the intake coefficients was 3.5:1 for phosphorus and 1.1:1 for nitrogen for the phytoplankton between these samples from around Baozhu Islet and Qingyu Islet, respectively. This indicates that the intake capabilities of phytoplankton for nitrogen in the two waters are essentially identical. However, for phosphorus, the capability was much higher in the Baozhu Islet waters than the Qingyu Islet waters. In other words, the phytoplankton in Qingyu Islet waters produced more biomass while consuming the same amount of phosphorus as the other waters; 2. The phytoplankton nitrogen and phosphorus intake ratio from the Baozhu Islet and Qingyu Islet waters was 20:1 and 36:1, respectively. The latter waters had a significantly higher ratio than the former and both were higher than the Redfield Ratio. These results indicate that nitrogen and phosphorus intake ratios by phytoplankton can vary significantly from region to region.

  3. [Biological phosphorus removal in intermittent aerated biological filter].

    PubMed

    Zeng, Long-Yun; Yang, Chun-Ping; Guo, Jun-Yuan; Luo, Sheng-Lian

    2012-01-01

    Under intermittent aerated and continuous fed operation where the biofilm system was subjected to alternated anaerobic/aerobic condition, the effect of influent volatile fatty acids (VFAs) concentrations, operation cycle and backwash on the biological phosphorus removal performance of the biofilter was studied. In the experiment, synthetic domestic wastewater was used, and the influent velocity was 5 L x h(-1) with gas versus liquid ratio of 8:1 and hydraulic retention time (HRT) of 1.3 h, resulting in average COD, ammonium and phosphorus load of 4.7, 0.41 and 0.095 g x (L x d) (-1) respectively. Results show that, (1) effective release and uptake of phosphorus was achieved in a operation cycle; (2) when influent VFAs was 100 mg x L(-1) (calculated by COD value) and operation cycle was 6 h the filter performed best in phosphorus removal, the phosphorus loading removal rate can be as much as 0.059 g x (L x d)(-1) at the aerated phase with those of COD and ammonium being 3.8 g x (L x d)(-1) and 0.28 g x (L x d)(-1) respectively, and with average effluent phosphorus, COD and ammonium concentrations being 1.8, 43.6 and 8.7 mg x L(-1), which shows nitrogen loss also happened; (3) the pause of backwash decreased the phosphorus removal performance rapidly with the removal efficiency lower than 40% in two days, but the consequent daily backwash operation gave a short improvement on the phosphorus removal, which disappeared in another two days. Thus, it is shown that biological phosphorus removal achieved with better phosphorus loading removal performance in the biofilter under intermittent aerated and continuous fed operation, and that sufficient and stable influent VFAs concentration, proper operation cycle, and more frequent backwash favored the performance.

  4. Improving phosphorus availability in an acid soil using organic amendments produced from agroindustrial wastes.

    PubMed

    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.

  5. Improving phosphorus availability in an acid soil using organic amendments produced from agroindustrial wastes.

    PubMed

    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

  6. 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

  7. [Forms and distributions of particulate phosphorus in the surface sediments of North Yellow Sea].

    PubMed

    Meng, Jia; Yao, Qing-Zhen; Chen, Hong-Tao; Yu, Zhi-Gang

    2012-10-01

    Surface sediments were collected from the North Yellow Sea in October 2007. The sediments were analyzed with modified SEDEX to obtain six forms of phosphorus. The results indicate that among the total phosphorus the detrital phosphorus and authigenic phosphorus are the main forms and the content varies from 25.7 to 122.5 microg x g(-1) and from 5.7 to 176.2 microg x g(-1), respectively, which taking up 17.0% -56.9% and 10.2% -49.8% of the total phosphorus. The content of exchangeable phosphorus, extractable organic phosphorus, iron-bound phosphorus and refractory phosphorus ranges from 5.5 to 43.9, from 4.1 to 41.4, from 2.3 to 26.7, from 6.0 to 33.6 microg x g(-1), respectively. Detrital and authigenic phosphorus are the major forms of the total phosphorus, indicating that the natural input is the major source of particle phosphorus in the study area. The content of iron-bound phosphorus is low, indicating that human input is minor in the area; mass fraction of the extractable organic phosphorus and refractory organic phosphorus is low, indicating that there is a low organic content while the main form of the total phosphorus is inorganic in the surface sediments of this area. Bioavailable phosphorus as exchangeable phosphorus, extractable organic phosphorus and iron-bound phosphorus account for 6.7% - 33.2% of the total particle phosphorus, indicating that bioavailability of phosphorus in the surface sediments is low.

  8. The Prevalence of Phosphorus Containing Food Additives in Top Selling Foods in Grocery Stores

    PubMed Central

    León, Janeen B.; Sullivan, Catherine M.; Sehgal, Ashwini R.

    2013-01-01

    Objective To determine the prevalence of phosphorus-containing food additives in best selling processed grocery products and to compare the phosphorus content of a subset of top selling foods with and without phosphorus additives. Design The labels of 2394 best selling branded grocery products in northeast Ohio were reviewed for phosphorus additives. The top 5 best selling products containing phosphorus additives from each food category were matched with similar products without phosphorus additives and analyzed for phosphorus content. Four days of sample meals consisting of foods with and without phosphorus additives were created and daily phosphorus and pricing differentials were computed. Setting Northeast Ohio Main outcome measures Presence of phosphorus-containing food additives, phosphorus content Results 44% of the best selling grocery items contained phosphorus additives. The additives were particularly common in prepared frozen foods (72%), dry food mixes (70%), packaged meat (65%), bread & baked goods (57%), soup (54%), and yogurt (51%) categories. Phosphorus additive containing foods averaged 67 mg phosphorus/100 gm more than matched non-additive containing foods (p=.03). Sample meals comprised mostly of phosphorus additive-containing foods had 736 mg more phosphorus per day compared to meals consisting of only additive-free foods. Phosphorus additive-free meals cost an average of $2.00 more per day. Conclusion Phosphorus additives are common in best selling processed groceries and contribute significantly to their phosphorus content. Moreover, phosphorus additive foods are less costly than phosphorus additive-free foods. As a result, persons with chronic kidney disease may purchase these popular low-cost groceries and unknowingly increase their intake of highly bioavailable phosphorus. PMID:23402914

  9. Detection of interstellar PN: the first phosphorus-bearing species observed in molecular clouds.

    PubMed

    Ziurys, L M

    1987-10-01

    Phosphorus nitride (PN) has been detected in the interstellar medium. The J = 2-1, 3-2, 5-4, and 6-5 rotational lines of this species have been observed toward Orion-KL, and the J = 2-1 transition in Sgr B2 and W51. The PN line profiles in Orion indicate that the molecule's emission arises from the "plateau" or "doughnut" region associated with the outflow from IRc2. The species is thus primarily present in hot, dense gas. Column densities derived for PN toward Orion-KL are 3-4 X 10(13) cm-2, but may be as high as 10(14) cm-2, if the species is located in a 10" region. These column densities imply a fractional abundance for PN in the Orion "plateau" of approximately 1-4 X 10(-10). Such a large abundance for phosphorus nitride is not predicted by quiescent cloud ion-molecule chemistry and suggests that high-temperature processes are responsible for the synthesis of PN in the KL outflow.

  10. The effects of wavelength and wavelength mixing ratios on microalgae growth and nitrogen, phosphorus removal using Scenedesmus sp. for wastewater treatment.

    PubMed

    Kim, Tae-Hyeong; Lee, Yunhee; Han, Su-Hyun; Hwang, Sun-Jin

    2013-02-01

    In wastewater treatment using microalgae, the effects of wavelength and wavelength mixing ratio on microalgae growth and removal of nitrogen and phosphorus were evaluated using LEDs (white light, 670nm, 450nm, and 525nm). Microalgae production rates were enhanced by a maximum of 45% with 400-700nm white light compared to that of a single wavelength. The phosphorus removal rate was as high as 90% with blue light. When red light and blue light were mixed and supplied, the microalgae production rate was about 50% higher than the rate of the culture with white light. Nitrogen and phosphorus removal rates were as high as approximately 15mg/L/day at a wavelength mixing ratio of 7 (red light):3 (blue light) and 2.1mg/L/day at a wavelength mixing ratio of 5 (red light):5 (blue light). PMID:23306113

  11. The effects of wavelength and wavelength mixing ratios on microalgae growth and nitrogen, phosphorus removal using Scenedesmus sp. for wastewater treatment.

    PubMed

    Kim, Tae-Hyeong; Lee, Yunhee; Han, Su-Hyun; Hwang, Sun-Jin

    2013-02-01

    In wastewater treatment using microalgae, the effects of wavelength and wavelength mixing ratio on microalgae growth and removal of nitrogen and phosphorus were evaluated using LEDs (white light, 670nm, 450nm, and 525nm). Microalgae production rates were enhanced by a maximum of 45% with 400-700nm white light compared to that of a single wavelength. The phosphorus removal rate was as high as 90% with blue light. When red light and blue light were mixed and supplied, the microalgae production rate was about 50% higher than the rate of the culture with white light. Nitrogen and phosphorus removal rates were as high as approximately 15mg/L/day at a wavelength mixing ratio of 7 (red light):3 (blue light) and 2.1mg/L/day at a wavelength mixing ratio of 5 (red light):5 (blue light).

  12. Electronic transport and mechanical properties of phosphorus and phosphorus-nitrogen doped carbon nanotubes

    SciTech Connect

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

    2009-01-01

    We present a density functional theory study of the electronic structure, quantum transport and mechanical properties of recently synthesized phosphorus (P) and phosphorus-nitrogen (PN) doped single-walled carbon nanotubes. The results demonstrate that substitutional P and PN doping creates localized electronic states that modify the electron transport properties by acting as scattering centers. For low doping concentrations (1 doping site per ~200 atoms), the quantum conductance for metallic nanotubes is found to be only slightly reduced. The substitutional doping also alters the mechanical strength, leading to a 50% reduction in the elongation upon fracture, while Young s modulus remains approximately unchanged. Overall, the PN- and P-doped nanotubes display promising properties for components in composite materials and, in particular, for fast response and ultra sensitive sensors operating at the molecular level.

  13. Conditional phosphorus index as an educational tool for risk assessment and phosphorus management.

    PubMed

    Djodjic, Faruk; Bergström, Lars

    2005-06-01

    Phosphorus index (PI) is a risk-assessment tool that combines phosphorus (P) source factors and transport factors to rank the vulnerability of fields to P losses. Here we present the structure and concepts of conditional PI, developed as an educational and P-management tool adjusted for Swedish conditions. Because the significance of certain factors for P losses depends on their interplay with other factors, conditional rules are needed for a more accurate process description and quantification. Accounting for P losses through the soil profile, separate calculations for reactive and unreactive P and a changed approach to P loss assessment from erosion losses are some of the new features included in the tool presented here. The performance of the tool was tested by comparing the calculated PI values with measured annual P transport from seven observation fields included in a Swedish water quality monitoring program. This first test indicated that the tool could be used successfully for P loss risk assessment.

  14. Effects of injection of acetic acid and propionic acid for total phosphorus removal at high temperature in enhanced biological phosphorus removal process.

    PubMed

    Ki, C Y; Kwon, K H; Kim, S W; Min, K S; Lee, T U; Park, D J

    2014-01-01

    In summer, wastewater treatment plant total phosphorus (TP) removal efficiency is low in South Korea. The reason is because of high temperatures or significant fluctuation of inflow characteristics caused by frequent rainfall. Hence, this study tried to raise TP removal efficiency by injecting fixed external carbon sources in real sewage. Polyphosphate accumulating organisms (PAOs) and glycogen accumulating organisms (GAOs) compete to occupy microorganisms at high temperature. Propionate is known to restrain GAOs. Thus, acetate and propionate were chosen as the external carbon source in this study to find out the suitable volume and ratio of carbon source which ensured the dominance of PAOs. An external carbon source was supplied in the anaerobic reactor of the biological phosphorus removal process at high temperature (above 25 °C). TP removal efficiency was improved by injecting an external carbon source compared to that without an external carbon source. Also, it remained relatively stable when injecting an external carbon source, despite the variation in temperature. TP removal efficiency was the highest when injecting acetate and propionate in the proportion of 2:1 (total concentration as chemical oxygen demand (COD) is 12 mg/L in influent).

  15. Effects of injection of acetic acid and propionic acid for total phosphorus removal at high temperature in enhanced biological phosphorus removal process.

    PubMed

    Ki, C Y; Kwon, K H; Kim, S W; Min, K S; Lee, T U; Park, D J

    2014-01-01

    In summer, wastewater treatment plant total phosphorus (TP) removal efficiency is low in South Korea. The reason is because of high temperatures or significant fluctuation of inflow characteristics caused by frequent rainfall. Hence, this study tried to raise TP removal efficiency by injecting fixed external carbon sources in real sewage. Polyphosphate accumulating organisms (PAOs) and glycogen accumulating organisms (GAOs) compete to occupy microorganisms at high temperature. Propionate is known to restrain GAOs. Thus, acetate and propionate were chosen as the external carbon source in this study to find out the suitable volume and ratio of carbon source which ensured the dominance of PAOs. An external carbon source was supplied in the anaerobic reactor of the biological phosphorus removal process at high temperature (above 25 °C). TP removal efficiency was improved by injecting an external carbon source compared to that without an external carbon source. Also, it remained relatively stable when injecting an external carbon source, despite the variation in temperature. TP removal efficiency was the highest when injecting acetate and propionate in the proportion of 2:1 (total concentration as chemical oxygen demand (COD) is 12 mg/L in influent). PMID:24845316

  16. Relative Contributions of Phosphorus in High Elevation Sierra Nevada Lakes

    NASA Astrophysics Data System (ADS)

    Jensen, L. K.; McIntyre, B. M.; Lyons, R. A.

    2015-12-01

    High elevation lakes of the Sierra Nevada mountain range show signs of eutrophication due to increased phosphorus loading. Phosphorus is a major contributing factor to freshwater lake eutrophication when in excess. Three previously researched sources of phosphorus to high-elevation montane lakes include atmospheric deposition, internal loading from sediments, and excretions from non-native stocked fish. The goal of this research was to isolate the estimated phosphorus contributions from residential shoreline developments and stocked non-native fish. A steady-state phosphorus loading rate model was created to quantify relative phosphorus loading into two lakes in the Eastern Sierra Nevada: Convict and Silver Lake. A conglomerate control lake was created from Eastern Brook Lake in the Eastern Sierra Nevada, Pear Lake in the Southern Sierra Nevada, and Snowflake Lake in Canada. Both Convict and Silver Lakes contain stocked non-native trout species and Silver Lake also has ~25 vacation homes on its eastern shore. Seasonal steady-state total phosphorus concentrations were determined using EPA Method 365.2. Loading rate constants were calculated using loading rates from literature and corresponding concentrations. It was determined that as much as 42% of phosphorous to Silver Lake came from shoreline housing developments, and 24% came from stocked fish depending on the season. Previous studies showed much lower contributions from non-native fish.

  17. Effect of pH on biological phosphorus uptake.

    PubMed

    Serralta, J; Ferrer, J; Borrás, L; Seco, A

    2006-12-01

    An anaerobic aerobic laboratory scale sequencing batch reactor (SBR) was operated to study the effect of pH on enhanced biological phosphorus removal. Seven steady states were achieved under different operating conditions. In all of them, a slight variation in the pH value was observed during anaerobic phase. However, pH rose significantly during aerobic phase. The increase observed was due to phosphorus uptake and carbon dioxide stripping. When pH was higher than 8.2-8.25 the phosphorus uptake rate clearly decreased. The capability of Activated Sludge Model No. 2d (ASM2d) and Biological Nutrient Removal Model No. 1 (BNRM1) to simulate experimental results was evaluated. Both models successfully characterized the enhanced biological phosphorus removal performance of the SBR. Furthermore, BNRM1 also reproduced the pH variations observed and the decrease in the phosphorus uptake rate. This model includes a switch function in the kinetic expressions to represent the pH inhibition in biological processes. The pH inhibition constants related to polyphosphate storage process were obtained by adjusting model predictions to measured phosphorus concentrations. On the other hand, pH inhibition should be included in ASM2d to accurately simulate experimental phosphorus evolution observed in an A/O SBR.

  18. Reduction of phosphorus and alkali levels in coking coals

    SciTech Connect

    Hoare, I.C.; Waugh, A.B.

    1995-12-31

    A number of coals, though exhibiting desirable coking properties, can have undesirable levels of alkalis and phosphorus. All the phosphorus in the coal will report to the coke, eventually to the iron and thence to the steel, with adverse effects on its metallurgical properties. Alkalis have damaging effects on the blast furnace operation and can be responsible for loss of heat, loss of production, efficiency loss and reduced furnace life. Buyers of coking coal commonly specify such parameters as phosphorus in coal and alkalis in ash, with penalties and rejection over certain limits. With the introduction of new direct reduction technologies such as COREX and HISMELT, and others such as PCI, it is anticipated that coal producers will have even tighter phosphorus and alkali specifications imposed on their products. Phosphorus is predominantly inorganic in origin occurring in a wide variety of minerals in coal, but its main source is apatite. It can be found mainly in the lower density fractions of the coal and intimately bound, so that conventional physical beneficiation techniques are relatively ineffective. CSIRO has developed a cost effective, selective chemical demineralization treatment, which can be applied to the problem of high alkali, high phosphorus coals. This particular technique makes use of unrefined organic acid, which also has the advantage of being low in cost and environmentally benign. In this paper, the effectiveness of acid demineralization of a number of coals is discussed, within the context of their phosphorus and alkali distributions throughout various size/density fractions.

  19. Preliminary analysis of phosphorus flow in Hue Citadel.

    PubMed

    Anh, T N Q; Harada, H; Fujii, S; Anh, P N; Lieu, P K; Tanaka, S

    2016-01-01

    Characteristics of waste and wastewater management can affect material flows. Our research investigates the management of waste and wastewater in urban areas of developing countries and its effects on phosphorus flow based on a case study in Hue Citadel, Hue, Vietnam. One hundred households were interviewed to gain insight into domestic waste and wastewater management together with secondary data collection. Next, a phosphorus flow model was developed to quantify the phosphorus input and output in the area. The results showed that almost all wastewater generated in Hue Citadel was eventually discharged into water bodies and to the ground/groundwater. This led to most of the phosphorus output flowing into water bodies (41.2 kg P/(ha year)) and ground/groundwater (25.3 kg P/(ha year)). Sewage from the sewer system was the largest source of phosphorus loading into water bodies, while effluent from on-site sanitation systems was responsible for a major portion of phosphorus into the ground/groundwater. This elevated phosphorus loading is a serious issue in considering surface water and groundwater protection.

  20. Black phosphorus saturable absorber for ultrashort pulse generation

    SciTech Connect

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

    2015-08-03

    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.

  1. Preliminary analysis of phosphorus flow in Hue Citadel.

    PubMed

    Anh, T N Q; Harada, H; Fujii, S; Anh, P N; Lieu, P K; Tanaka, S

    2016-01-01

    Characteristics of waste and wastewater management can affect material flows. Our research investigates the management of waste and wastewater in urban areas of developing countries and its effects on phosphorus flow based on a case study in Hue Citadel, Hue, Vietnam. One hundred households were interviewed to gain insight into domestic waste and wastewater management together with secondary data collection. Next, a phosphorus flow model was developed to quantify the phosphorus input and output in the area. The results showed that almost all wastewater generated in Hue Citadel was eventually discharged into water bodies and to the ground/groundwater. This led to most of the phosphorus output flowing into water bodies (41.2 kg P/(ha year)) and ground/groundwater (25.3 kg P/(ha year)). Sewage from the sewer system was the largest source of phosphorus loading into water bodies, while effluent from on-site sanitation systems was responsible for a major portion of phosphorus into the ground/groundwater. This elevated phosphorus loading is a serious issue in considering surface water and groundwater protection. PMID:26744936

  2. Large Ultraviolet Photoresponsivity of Few-layer Black Phosphorus

    NASA Astrophysics Data System (ADS)

    Wu, Jing; Kok Wai Koon, Gavin; Xiang, Du; Castro Neto, Antonio H.; Özyilmaz, Barbaros; Centre of Advanced 2D Materials Team

    Black phosphorus has recently gained much attention in the scientific community. Black phosphorus can be seen as a crystal generated by periodic repetition of tetraphosphorus (P4) molecules. It is known that tetraphosphorus P4 can be transformed temporarily to diphosphorus P2 upon ultraviolet (UV) irradiation. Thus, it is expected that the P4 structured black phosphorus also has strong interaction with light especially in the UV range. Here we report on the optoelectronic characteristics of few-layer black phosphorus field effect transistors (FETs) ranging from the UV to the near infrared (NIR). We demonstrate that black phosphorus is an excellent ultraviolet (UV) photodetector with a specific detectivity ~3x1013 Jones. We report also an exceptional photo responsivity of 107 times higher than previously reported values for black phosphorus visible light photodetectors. We attribute such a colossal UV photo responsivity to the resonant-interband transition between two specially nested valence and conduction bands. These nested bands provide an unusually high density of states for high-efficient UV absorption due to their singularity nature. Large Ultraviolet Photoresponsivity of Few-layer Black Phosphorus.

  3. Phosphorus removal from anaerobically digested swine wastewater through struvite precipitation.

    PubMed

    Jordaan, E M; Ackerman, J; Cicek, N

    2010-01-01

    Phosphorus removal from agricultural wastewater streams is an important aspect of managing surface water quality, due to the contribution of phosphorus to eutrophication. Removal of phosphorus through struvite precipitation allows for its recovery as a potential fertilizer, and by determining the best conditions for struvite precipitation the removal process can be optimized. The effects of pH, Mg:P ratio, and time on struvite precipitation from anaerobically digested swine manure effluent were investigated. Effluent with Mg:P ratios from 1.0:1 to 1.6:1 were adjusted to pH values between 7.5 and 9.5 and left to equilibrate for 24 h. Results indicate that phosphorus removal increased with increasing pH and Mg:P ratio; the maximum phosphorus removal achieved was 80% at pH 9.0 and a Mg:P ratio of 1.6:1. The purest struvite precipitate was found at pH 7.5, with calcium carbonate and struvite precipitating at higher pH values. A continuously stirred batch of centrate was adjusted to pH 8.4 to determine the struvite formation rate constant. The rate constant was found to be 1.55 h(-1), with 17% phosphorus removal during the first 20 min. The results indicate that struvite precipitation could be a viable method of phosphorus removal from anaerobically digested swine manure.

  4. Microbial sequestration of phosphorus in anoxic upwelling sediments

    NASA Astrophysics Data System (ADS)

    Goldhammer, Tobias; Brüchert, Volker; Ferdelman, Timothy G.; Zabel, Matthias

    2010-08-01

    Phosphorus is an essential nutrient for life. In the ocean, phosphorus burial regulates marine primary production. Phosphorus is removed from the ocean by sedimentation of organic matter, and the subsequent conversion of organic phosphorus to phosphate minerals such as apatite, and ultimately phosphorite deposits. Bacteria are thought to mediate these processes, but the mechanism of sequestration has remained unclear. Here, we present results from laboratory incubations in which we labelled organic-rich sediments from the Benguela upwelling system, Namibia, with a 33P-radiotracer, and tracked the fate of the phosphorus. We show that under both anoxic and oxic conditions, large sulphide-oxidizing bacteria accumulate 33P in their cells, and catalyse the nearly instantaneous conversion of phosphate to apatite. Apatite formation was greatest under anoxic conditions. Nutrient analyses of Namibian upwelling waters and sediments suggest that the rate of phosphate-to-apatite conversion beneath anoxic bottom waters exceeds the rate of phosphorus release during organic matter mineralization in the upper sediment layers. We suggest that bacterial apatite formation is a significant phosphorus sink under anoxic bottom-water conditions. Expanding oxygen minimum zones are projected in simulations of future climate change, potentially increasing sequestration of marine phosphate, and restricting marine productivity.

  5. The dissipation of phosphorus in sewage and sewage effluents.

    PubMed

    Collingwood, R W

    Of the 41 kt of phosphorus reaching the sewage works in England and Wales 15 kt is removed in sewage sludge and the remainder is disposed of to rivers. 60% of the sewage sludge is now used as fertilizer and this proportion will no doubt increase in the future. The total use of sewage sludge, however, represents only about 5% of the current annual usage of artificial phosphorus fertilizer. At present there is no general economic incentive to make better use of the phosphorus in effluents. Phosphorus removal is expensive--about 2--3 pence/m3. If all the sewage effluents in England and Wales were to be so treated the cost would be about 100--150 million pounds annually, that is about 50% of the present costs of sewage treatment. In certain cases, but rarely in the UK, phosphate is removed, not to conserve phosphorus but to minimize the problems it creates in the environment. The phosphorus removed has little value as fertilizer. Alternative methods of using the phosphorus in effluents by the production and harvesting of crops of algae or aquatic plants have so far proved uneconomic. However, these methods need to be reviewed periodically as they may in the future become economically more attractive, especially in warmer climates where plant growth can be maintained throughout the year. PMID:357121

  6. 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.

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

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... phosphorus oxychloride creates waste water pollutants not completely amenable to the procedures utilized for... phosphorus consuming subcategory. 422.20 Section 422.20 Protection of Environment ENVIRONMENTAL PROTECTION... Phosphorus Consuming Subcategory § 422.20 Applicability; description of the phosphorus consuming...

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

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... phosphorus oxychloride creates waste water pollutants not completely amenable to the procedures utilized for... phosphorus consuming subcategory. 422.20 Section 422.20 Protection of Environment ENVIRONMENTAL PROTECTION... Phosphorus Consuming Subcategory § 422.20 Applicability; description of the phosphorus consuming...

  9. 40 CFR 422.20 - Applicability; description of the phosphorus consuming subcategory.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... phosphorus oxychloride creates waste water pollutants not completely amenable to the procedures utilized for... phosphorus consuming subcategory. 422.20 Section 422.20 Protection of Environment ENVIRONMENTAL PROTECTION... Phosphorus Consuming Subcategory § 422.20 Applicability; description of the phosphorus consuming...

  10. 40 CFR 422.20 - Applicability; description of the phosphorus consuming subcategory.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... phosphorus oxychloride creates waste water pollutants not completely amenable to the procedures utilized for... phosphorus consuming subcategory. 422.20 Section 422.20 Protection of Environment ENVIRONMENTAL PROTECTION... Phosphorus Consuming Subcategory § 422.20 Applicability; description of the phosphorus consuming...

  11. 40 CFR 422.20 - Applicability; description of the phosphorus consuming subcategory.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... phosphorus oxychloride creates waste water pollutants not completely amenable to the procedures utilized for... phosphorus consuming subcategory. 422.20 Section 422.20 Protection of Environment ENVIRONMENTAL PROTECTION... Phosphorus Consuming Subcategory § 422.20 Applicability; description of the phosphorus consuming...

  12. Impact of fertilizer phosphorus application on phosphorus release kinetics in some calcareous soils

    NASA Astrophysics Data System (ADS)

    Hosseinpur, A. R.; Biabanaki, F. S.

    2009-01-01

    Phosphate reactions and retention in the soil are of paramount importance from the perspective of plant nutrition and fertilizer use efficiency. The objective of this work was to study the kinetics of phosphorus (P) desorption in different soils of Hamadan in fertilized and unfertilized soils. Soils were fertilized with 200 mg P kg-1. Fertilized and unfertilized soils were incubated at 25 ± 1°C for 6 months. After that, release of P was studied by successive extraction with 0.5 M NaHCO3 over a period of 1,752 h. The results showed that phosphorus desorption from the fertilized and unfertilized soils began with a fast initial reaction, followed by a slow secondary reaction. The amount of P released after 1,752 h in fertilized and unfertilized soils ranged from 457 to 762.4 and 309.6 to 586.7 mg kg-1, respectively. The kinetics of cumulative P release was evaluated using the five kinetic equations. Phosphorus desorption kinetics were best described by parabolic diffusion law, first order, and power function equations. Rate constants of these equations were higher in fertilized than unfertilized soils. Results from this study indicate that release rate of P plays a significant role in supplying available P and released P in runoff.

  13. Typhoon effects on phosphorus dynamics in a subtropical reservoir

    NASA Astrophysics Data System (ADS)

    Chow, Ming Fai

    2013-04-01

    Intense storm event during typhoon period is identified that will significantly alter the content of phosphorus in the water body of reservoir. However, the fate and transport of phosphorus in aquatic environments that triggered by typhoons is poorly understanded. Better understanding of typhoon impacts on the runoff mechanism of phosphorus will be useful in improving the management of water pollution and reduce the impairment to the drinking water sources. In this study, three typhoon events namely Talim, Saola and Tembin which occurred in between June and August 2012 were investigated through continuous sampling (every 3 hours) at five main tributaries at the upstream of Fei-Tsui reservoir, Taiwan. In addition, weekly sampling was conducted at different depths throughout the water column at the dam site. For all water samples, in situ measurements of pH, temperature, electrical conductivity (EC) and dissolved oxygen (DO) were conducted. The water samples had been analysed for total suspended solid (TSS), dissolved inorganic phosphorus (DIP), dissolved organic phosphorus (DOP), particulate phosphorus (PP) and total phosphorus (TP). Results indicated that high intense typhoon storm had caused a 2-10 times increase in DIP compared with the moderate storm and base flow condition. Correlation analysis showed that TP was positively correlated with TSS. That indicates the turbidity current can be a source of phosphorus. All nutrients showed a contrasting hysteresis pattern, which reflecting different supply of source and transport mechanism. PP was mainly originated from overland surface runoff and resuspension of sediment from the river bottom, while DIP was supplied from both surface and subsurface flow. High PP concentration was observed during the early part of storm runoff at the upstream river. Results suggested that first flush effect was evident for PP. These findings had improved the understanding on fate and transport of phosphorus in the reservoir watershed

  14. Domestic source of phosphorus to sewage treatment works.

    PubMed

    Comber, Sean; Gardner, Michael; Georges, Karyn; Blackwood, David; Gilmour, Daniel

    2013-01-01

    Phosphorus is an element essential for life. Concerns regarding long-term security of supply and issues related to eutrophication of surface waters once released into the aquatic environment have led governments to consider and apply measures for reducing the use and discharge of phosphorus. Examples of source control include legislation to reduce phosphorus use in domestic detergents. This research shows that other domestic sources of phosphorus also contribute significantly to the domestic load to sewer and that overall, domestic sources dominate loads to sewage treatment works. Estimates provided here show that although the natural diet contributes 40% of the domestic phosphorus load, other potentially preventable sources contribute significantly to the estimated 44,000 tonnes of phosphorus entering UK sewage treatment works each year. In the UK, food additives are estimated to contribute 29% of the domestic load; automatic dishwashing detergents contribute 9% and potentially increasing; domestic laundry 14%, including contributions from phosphonates, but decreasing; phosphorus dosing to reduce lead levels in tap water 6%; food waste disposed of down the drain 1%; and personal care products 1%. Although UK data is presented here, it is anticipated that similar impacts would be expected for other developed economies. Consideration of alternatives to all preventable sources of phosphorus from these sources would therefore offer potentially significant reductions in phosphorus loads to sewage treatment works and hence to the aquatic environment. Combining all source control measures and applying them to their maximum extent could potentially lead to the prevention of over 22,000 tonnes-P/year entering sewage treatment works.

  15. Copper-phosphorus alloys offer advantages in brazing copper

    SciTech Connect

    Rupert, W.D.

    1996-05-01

    Copper-phosphorus brazing alloys are used extensively for joining copper, especially refrigeration and air-conditioning copper tubing and electrical conductors. What is the effect of phosphorus when alloyed with copper? The following are some of the major effects: (1) It lowers the melt temperature of copper (a temperature depressant). (2) It increases the fluidity of the copper when in the liquid state. (3) It acts as a deoxidant or a fluxing agent with copper. (4) It lowers the ductility of copper (embrittles). There is a misconception that silver improves the ductility of the copper-phosphorus alloys. In reality, silver added to copper acts in a similar manner as phosphorus. The addition of silver to copper lowers the melt temperature (temperature depressant) and decreases the ductility. Fortunately, the rate and amount at which silver lowers copper ductility is significantly less than that of phosphorus. Therefore, taking advantage of the temperature depressant property of silver, a Ag-Cu-P alloy can be selected at approximately the same melt temperature as a Cu-P alloy, but at a lower phosphorus content. The lowering of the phosphorus content actually makes the alloy more ductile, not the silver addition. A major advantage of the copper-phosphorus alloys is the self-fluxing characteristic when joining copper to copper. They may also be used with the addition of a paste flux on brass, bronze, and specialized applications on silver, tungsten and molybdenum. Whether it is selection of the proper BCuP alloy or troubleshooting an existing problem, the suggested approach is a review of the desired phosphorus content in the liquid metal and how it is being altered during application. In torch brazing, a slight change in the oxygen-fuel ratio can affect the joint quality or leak tightness.

  16. Living donor liver transplantation for acute liver failure in pediatric patients caused by the ingestion of fireworks containing yellow phosphorus.

    PubMed

    Ates, Mustafa; Dirican, Abuzer; Ozgor, Dincer; Aydin, Cemalettin; Isik, Burak; Ara, Cengiz; Yilmaz, Mehmet; Ayse Selimoglu, M; Kayaalp, Cuneyt; Yilmaz, Sezai

    2011-11-01

    Yellow phosphorus is a protoplasmic toxicant that targets the liver. The ingestion of fireworks containing yellow phosphorus, either by children who accidentally consume them or by adults who are attempting suicide, often results in death due to acute liver failure (ALF). We present the outcomes of 10 children who ingested fireworks containing yellow phosphorus. There were 6 boys and 4 girls, and their ages ranged from 21 to 60 months. One patient remained stable without liver complications and was discharged. Three patients died of hepatorenal failure and cardiovascular collapse, and living donor liver transplantation (LDLT) was performed for 6 patients. The patients had grade II or III encephalopathy, a mean alanine aminotransferase level of 1148.2 IU/L, a mean aspartate aminotransferase level of 1437.5 IU/L, a mean total bilirubin level of 6.9 mg/dL, a mean international normalized ratio of 6.6, a mean Pediatric End-Stage Liver Disease score of 33.7, and a mean Child-Pugh score of 11.3. Postoperatively, 2 patients had persistent encephalopathy and died on the second or third postoperative day, and 1 patient died of cardiac arrest on the first postoperative day despite a well-functioning graft. The other 3 patients were still alive at a mean of 204 days. In conclusion, the ingestion of fireworks containing yellow phosphorus causes ALF with a high mortality rate. When signs of irreversible ALF are detected, emergency LDLT should be considered as a lifesaving procedure; however, if yellow phosphorus toxicity affects both the brain and the heart in addition to the liver, the mortality rate remains very high despite liver transplantation.

  17. 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.

  18. Vanadium reduces mortality in phosphorus deficient chicks

    SciTech Connect

    Hill, C.H. )

    1991-03-15

    Since the vanadate anion is similar in structure to the phosphate ion, and since vanadate has been shown to interfere with phosphate metabolism both in vitro and in vivo, experiments were conducted to determine the effect of dietary vanadate (V) on chicks fed phosphorus (P) deficient diets. In these studies, broiler chicks of both sexes were fed the experimental diets from the day of hatching for 19 days. The diets were based on soybean meal and corn, supplemented with methionine, manganese, and vitamins to supply the chick's requirements. Calcium (Ca) and P levels were manipulated by use of feed grade dicalcium phosphate and limestone. V was added as ammonium metavanadate. Serum Ca and P were determined on representative chicks in each group. Increasing Ca levels increased serum Ca and decreased serum P. V increased serum P levels in the chicks receiving 0.2% P but not in those receiving 0.1% P.

  19. Biological phosphorus cycling in dryland regions

    USGS Publications Warehouse

    Belnap, Jayne; Bunemann, Else; Oberson, Astrid; Frossard, Emmanuel

    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

  20. Black phosphorus edges: a polarized Raman study

    NASA Astrophysics Data System (ADS)

    Ribeiro, H.; Villegas, C.; Bahamon, D.; Castro Neto, A.; de Souza, E.; Rocha, A.; Pimenta, M.; de Matos, C.

    Black phosphorus (BP) has been recently exfoliated down to few-layer thicknesses revealing numerous interesting features such as a tunable direct bandgap. Ever since, demonstrations of BP electronic devices have bloomed, as well as studies of the electric, optical, mechanical and thermal properties of its bulk and few-layer forms. However, the edges of BP crystals have, so far, been poorly characterized, even though the terminations of layered crystals are known to possess a range of interesting properties. In this work, the edges of exfoliated BP flakes are characterized by polarized confocal Raman spectroscopy. We will present experimental Raman spectra at zigzag and armchair edges, as well as density functional theory calculations that explain the peculiarities of the experimental data. Fapesp, INCT/Nanocarbono, Fapemig, CNPq, MackPesquisa, Grid-Unesp, CENAPAD-SP, and NRF.

  1. Black Phosphorus Nanosheets: Synthesis, Characterization and Applications.

    PubMed

    Eswaraiah, Varrla; Zeng, Qingsheng; Long, Yi; Liu, Zheng

    2016-07-01

    Black phosphorus (BP) is an emerging two-dimensional (2D) material with a natural bandgap, which has unique anisotropy and extraordinary physical properties. Due to its puckered structure, BP exhibits strong in-plane anisotropy unlike other layered materials. The bandgap tunability of BP enables a wide range of ultrafast electronics and high frequency optoelectronic applications ranging from telecommunications to thermal imaging covering the nearly entire electromagnetic spectrum, whereas no other 2D material has this functionality. Here, recent advances in the synthesis, fabrication, anisotropic physical properties, and BP-based devices including field effect transistors (FETs) and photodetectors, are discussed. Recent passivation approaches to address the degradation of BP, which is one of the main challenges to bring this material into real world applications, are also introduced. Finally, a comment is made on the recent developments in other emerging applications, future outlook and challenges ahead in BP research. PMID:27225670

  2. 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.

  3. 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.

  4. A Novel Method for Dissolved Phosphorus Analysis

    NASA Astrophysics Data System (ADS)

    Berry, J. M.; Spiese, C. E.

    2012-12-01

    High phosphorus loading is a major problem in the Great Lakes watershed. Phosphate enters waterways via both point and non-point sources (e.g., runoff, tile drainage, etc.), promoting eutrophication, and ultimately leading to algal blooms, hypoxia and loss of aquatic life. Quantification of phosphorus loading is typically done using the molybdenum blue method, which is known to have significant drawbacks. The molybdenum blue method requires strict control on time, involves toxic reagents that have limited shelf-life, and is generally unable to accurately measure sub-micromolar concentrations. This study aims to develop a novel reagent that will overcome many of these problems. Ethanolic europium(III) chloride and 8-hydroxyquinoline-5-sulfonic acid (hqs) were combined to form the bis-hqs complex (Eu-hqs). Eu-hqs was synthesized as the dipotassium salt via a simple one-pot procedure. This complex was found to be highly fluorescent (λex = 360 nm, λem = 510 nm) and exhibited a linear response upon addition of monohydrogen phosphate. The linear response ranged from 0.5 - 25 μM HPO42- (15.5 - 775 μg P L-1). It was also determined that Eu-hqs formed a 1:1 complex with phosphate. Maximum fluorescence was found at a pH of 8.50, and few interferences from other ions were found. Shelf-life of the reagent was at least one month, twice as long as most of the molybdenum blue reagent formulations. In the future, field tests will be undertaken in local rivers, lakes, and wetlands to determine the applicability of the complex to real-world analysis.

  5. The toxicants and phosphorus content of some Nigerian vegetables.

    PubMed

    Udosen, E O; Ukpanah, U M

    1993-11-01

    The oxalate, hydrocyanic acid, phytic acid and phosphorus contents of twelve leafy vegetables were determined. The values ranged from 47.7-194.3 mg/100 g DM, 4.32-23.8 mg/100 g DM, 90-260 mg/100 g DM and 215-1110 mg/100 g DM, respectively. The ratio of phytic acid to phosphorus ranged from 13.9-90.7. The leaves contained low levels of hydrocyanic acid, while the oxalate, phytic acid and phosphorus contents were high. The results are discussed in terms of their clinical implications and nutritive values. PMID:8295869

  6. Effect of sludge retention time and phosphorus to carbon ratio on biological phosphorus removal in HS-SBR process.

    PubMed

    Zhu, Rui; Wu, Min; Yang, Jian

    2013-01-01

    Sludge retention time (SRT) and phosphorus to carbon ratio (P/C) in the feed are important control parameters in biological phosphorus removal. In this study, humus soil sequencing batch reactor (HS-SBR) process was operated with different SRTs (five, 10 and 15 days) and P/C feeding (0.0125 and 0.1) to evaluate their phosphorus removal efficiencies. The HS-SBR was composed of a humus soil reactor (HSR) and a conventional SBR (designated as hsSBR to differentiate from the conventional SBR used as a control). The results showed that the phosphorus removal efficiency was 82.7%, 97.3% and 97.3% at SRTs of five, 10 and 15 days respectively and acetate utilization efficiency for phosphorus release with SRTs of 10 and 15 days was much higher than that with an SRT of five days. In addition, a high P/C feeding (0.1) could promote the growth of the phosphate accumulating organisms in the hsSBR; however, the efficiency of phosphorus removal was lower than a low P/C feeding (0.0125) at an SRT of 15 days. All these observations suggested that a relatively long SRT and low P/C feeding exert a useful effect on the phosphorus removal in the hsSBR.

  7. 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.

  8. The embrittling/strengthening effects of hydrogen, boron, and phosphorus on a {Sigma}5 nickel grain boundary

    SciTech Connect

    Raynolds, J.E.; Geng, W.T.; Freeman, A.J.; Wu, R.; Geller, C.B.

    1999-07-01

    The embrittling/strengthening effects of hydrogen, boron, and phosphorus on a {Sigma}5(21O) [100]nickel grain boundary are investigated by means of the full-potential linearized augmented plane wave (FLAPW) method with the generalized gradient approximation (GGA) formula. Optimized geometries for both the free surface and grain boundary systems are obtained by atomic force calculations. The results obtained show that hydrogen and phosphorus are embrittlers and that boron acts as a cohesion enhancer. An analysis of the atomic, electronic, and magnetic structures indicates that atomic size and the bonding behavior of the impurity with the surrounding nickel atoms play important roles in determining its relative embrittling or cohesion enhancing behavior.

  9. Is phosphorus intake that exceeds dietary requirements a risk factor in bone health?

    PubMed

    Calvo, Mona S; Tucker, Katherine L

    2013-10-01

    Phosphorus intake in excess of the nutrient needs of healthy adults is thought to disrupt hormonal regulation of phosphorus (P), calcium (Ca), and vitamin D, contributing to impaired peak bone mass, bone resorption, and greater risk of fracture. Elevation of extracellular phosphorus due to excessive intake is thought to be the main stimulus disrupting phosphorus homeostasis in healthy individuals, as it is in renal disease even when intake is modest. If high serum phosphorus is the critical link to the effect of high phosphorus intake on bone health, the issue could be addressed through epidemiologic or dietary studies. However, several confounding factors, including problems estimating accurate phosphorus intake, the influence of a low dietary Ca:P ratio, the acidic nature of phosphorus, the rapid rate of absorption and greater phosphorus bioavailability from processed food such as cola drinks, and circadian fluctuation in serum phosphorus, make this question difficult to address using conventional study designs. These confounding factors are considered in this review, exploring whether phosphorus intake exceeding nutrient needs in healthy individuals disrupts phosphorus regulation and negatively affects bone accretion or loss. Specific attention is given to phosphorus intake from processed foods rich in phosphorus additives, which significantly contribute to phosphorus intake.

  10. Phosphorus contents and availability of technogenic substrates for soil construction

    NASA Astrophysics Data System (ADS)

    Nehls, Thomas; Lydia, Paetsch; Sarah, Rokia; Schwartz, Christophe; Wessolek, Gerd

    2014-05-01

    Urban areas lack of green and of soil substrates to support this green. A great variety of solid waste materials can be seen as technogenic substances (TS) for the construction of soil-similar plant substrates. Biomass production in the city and the use of waste materials as nutrient sources can help to close regional nutrient cycles. The most important waste materials have been studied for their phosphorus contents, availabilities and diffusion rates in the rhizosphere by combining their analyzed chemical and physical properties. Compost, concrete, green wastes, paper mill sludge, street-sweepings, mix of rubble, bricks, track ballasts and charcoal have (i) been analyzed their P release properties (HF extraction, Olsen-P, adsorption isotherms); (ii) the physical properties (water retention function, saturated hydraulic conductivity) were analyzed at 80 % of the proctor density; (iii) The P availability of the TMs to the roots were simulated for different pressure heads (pF = 1.3, 1.8 and 3.0) using HYDRUS 1-D. We compared the results for TS with these for agricultural soils. Ptot varies from 710 to 21 000 mg kg-1 for bricks and compost, while POlsen varies from 19 to 1 090 mg kg-1 for charcoal and green wastes. The diffusion rates of TSs (pF = 1.3) are up to 10 times higher compared to those of soils, with green wastes showing highest and bricks the lowest P diffusion rates. We conclude that the investigated TS are appropriate for construction of soil similar planting substrates because of their P delivery potential and their favourable physical properties.

  11. White phosphorus pits focused feasibility study final July 2007.

    SciTech Connect

    Davis, B.; Martino, L.

    2007-08-21

    The White Phosphorus Burning Pits (WPP) Area of Concern (AOC) is a site of about 5.5 acres (2.2 ha) located in the J-Field Study Area, in the Edgewood Area of Aberdeen Proving Ground (APG), Maryland (Figure 1.1). Considerable information about the WPP exists as a result of efforts to characterize the hazards associated with J-Field. Contamination in the J-Field Study Area was first detected during an environmental survey of the APG Edgewood Area conducted in 1977 and 1978 (Nemeth et al. 1983) by the U.S. Army Toxic and Hazardous Materials Agency (USATHAMA; predecessor to the U.S. Army Environmental Center). As part of a subsequent USATHAMA environmental survey, 11 wells were installed and sampled at J-Field (three of them at the WPP) (Nemeth 1989). Contamination was also detected in 1983 during a munitions disposal survey conducted by Princeton Aqua Science (1984). The Princeton Aqua Science investigation involved installing and sampling nine wells (four at the WPP) and collecting and analyzing surficial and deep composite soil samples (including samples from the WPP area). In 1986, the U.S. Environmental Protection Agency (EPA) issued a Resource Conservation and Recovery Act (RCRA) Permit (MD3-21-002-1355) requiring a post-wide RCRA Facility Assessment (RFA) and a hydrogeologic assessment of J-Field. In 1987, the U.S. Geological Survey (USGS) began a two-phase hydrogeologic assessment in which data were collected to model groundwater flow at J-Field. Soil-gas investigations were conducted, several well clusters were installed (four at the WPP), a groundwater flow model was developed, and groundwater and surface water monitoring programs were established that continue today. The results of the USGS study were published by Hughes (1993).

  12. Imbalanced phosphorus and nitrogen deposition in China's forests

    NASA Astrophysics Data System (ADS)

    Du, Enzai; de Vries, Wim; Han, Wenxuan; Liu, Xuejun; Yan, Zhengbing; Jiang, Yuan

    2016-07-01

    Acceleration of anthropogenic emissions in China has substantially increased nitrogen (N) deposition during the last 3 decades and may result in an imbalance of atmospheric N and phosphorus (P) inputs in terrestrial ecosystems. However, the status of P deposition in China is poorly understood. This study synthesized data on total P and total N concentrations in bulk precipitation and throughfall from published literature to assess the characteristics of P deposition, N deposition and N : P deposition ratio in China's forests. Our results show relatively high mean rates of bulk P deposition (0.38 kg P ha-1 yr-1) and total P deposition (0.69 kg P ha-1 yr-1), but they were accompanied by even more elevated N inputs via bulk deposition (16.5 kg N ha-1 yr-1) and total deposition (21.6 kg N ha-1 yr-1), resulting in high N : P ratios in bulk deposition (44.4) and total deposition (32.8). Based on the difference between total deposition and bulk deposition, canopy-captured dry P and N deposition was estimated to be 0.31 kg P ha-1 yr-1 and 5.1 kg N ha-1 yr-1, respectively. We found significantly higher P deposition and lower N : P ratios at sites nearby than those far from semiarid regions. The estimated bulk and total deposition of P and N both showed a significant power-law increase with decreasing distance to the nearest large cities either in the areas nearby or far from semiarid regions. Our results suggest an anthropogenic alternation of regional P and N cycling, which may shift large areas of China's forests towards human-induced P limitation especially in southern China.

  13. A single phosphorus treatment doubles growth of cyanobacterial lichen transplants.

    PubMed

    McCune, Bruce; Caldwell, Bruce A

    2009-02-01

    Lichens are reputedly slow growing and become unhealthy or die in response to supplements of the usual limiting resources, such as water and nitrogen. We found, however, that the tripartite cyanobacterial lichen Lobaria pulmonaria doubled in annual biomass growth after a single 20-minute immersion in a phosphorus solution (K2HPO4), as compared to controls receiving no supplemental phosphorus. This stimulation of cyanolichens by phosphorus has direct relevance to community and population ecology of lichens, including improving models of lichen performance in relation to air quality, improving forest management practices affecting old-growth associated cyanolichens, and understanding the distribution and abundance of cyanolichens on the landscape. Phosphorus may be as important a stimulant to cyanobacterial-rich lichen communities as it is to cyanobacteria in aquatic ecosystems. PMID:19323240

  14. 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)

  15. Primary sources of phosphorus and phosphates in chemical evolution.

    PubMed

    Macia, E; Hernandez, M V; Oro, J

    1997-12-01

    In this work we consider the role of phosphorus in chemical evolution from an interdisciplinary approach. First we briefly review the presence of this element in different cosmic sites, such as massive stellar cores, circumstellar and interstellar clouds, meteorites, lunar and Martian samples, interplanetary dust particles, cometary dust and planetary atmospheres. Thus we illustrate the fact that phosphorus seems to be, at the same time, scarce and ubiquitous in the solar system. Afterwards, by comparing the phosphorus content of our planet's main reservoirs with the amount of cometary and meteoritic matter captured by the primitive Earth, we conclude that comets may have provided a primary source for phosphorus compounds of prebiotic interest. Finally, we make a number of proposals aimed to gain observational supporting evidence to the above conclusion and other suggestions made in the article.

  16. Phosphorus limitation on bacterial regrowth in drinking water.

    PubMed

    Sang, Jun-qiang; Zhang, Xi-hui; Yu, Guo-zhong; Wang, Zhan-sheng

    2003-11-01

    Assimilable organic carbon (AOC) test and bacterial regrowth potential (BRP) analysis were used to investigate the effect of phosphorus on bacterial regrowth in the drinking water that was made from some raw water taken from a reservoir located in northern China. It was shown that AOC of the drinking water samples increased by 43.9%-59.6% and BRP increased by 100%-235% when 50 microg/L PO4(3-)-P(as NaH2 PO4) was added alone to the drinking water samples. This result was clear evidence of phosphorus limitation on bacteria regrowth in the drinking water. This investigation indicated the importance of phosphorus in ensuring biological stability of drinking water and offered a novel possible option to restrict microbial regrowth in drinking water distribution system by applying appropriate technologies to remove phosphorus efficiently from drinking water in China.

  17. Black phosphorus photodetector for multispectral, high-resolution imaging.

    PubMed

    Engel, Michael; Steiner, Mathias; Avouris, Phaedon

    2014-11-12

    Black phosphorus is a layered semiconductor that is intensely researched in view of applications in optoelectronics. In this letter, we investigate a multilayer black phosphorus photodetector that is capable of acquiring high-contrast (V > 0.9) images both in the visible (λVIS = 532 nm) as well as in the infrared (λIR = 1550 nm) spectral regime. In a first step, by using photocurrent microscopy, we map the active area of the device and we characterize responsivity and gain. In a second step, by deploying the black phosphorus device as a point-like detector in a confocal microsope setup, we acquire diffraction-limited optical images with submicron resolution. The results demonstrate the usefulness of black phosphorus as an optoelectronic material for hyperspectral imaging applications.

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

    SciTech Connect

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

    1989-07-25

    A method of removing organic phosphorus-based poisonous substances from water contaminated therewith and of subsequently destroying the toxicity of the substances 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.

  19. Phosphorus Removal from Silicon by Vacuum Refining and Directional Solidification

    NASA Astrophysics Data System (ADS)

    Jiang, Dachuan; Ren, Shiqiang; Shi, Shuang; Dong, Wei; Qiu, Jieshan; TAN, Yi; Li, Jiayan

    2014-02-01

    Silicon is widely used as a raw material for production of solar cells. As a major impurity in silicon, phosphorus must be removed to 1 × 10-5 wt.%. In the present study, based on the distribution of phosphorus in a silicon ingot obtained by vacuum refining and directional solidification, the mechanism for removal of phosphorus from silicon is investigated. The results show that the distribution is controlled not only by segregation at the solid-liquid interface but also by evaporation at the gas-liquid interface, showing some deviation from Scheil's equation. A modified model which considers both segregation and evaporation is used to simulate the distribution, matching quite well with the experimental results. The temperature and solidification rate are two important parameters that affect the overall mass transfer coefficient and the effective segregation coefficient and thus the distribution of phosphorus. A high removal efficiency and a homogeneous distribution can be obtained by adjusting these two parameters.

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

    DOEpatents

    Vandegrift, George F.; Steindler, Martin J.

    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.

  1. Selective nitration and bromination of surprisingly ruffled phosphorus corroles.

    PubMed

    Pomarico, Giuseppe; Tortora, Luca; Fronczek, Frank R; Smith, Kevin M; Paolesse, Roberto

    2016-05-01

    Phosphorus complexes of corrole have recently attracted increasing interest since these compounds can be easily prepared in good yields, are stable, and show unusual optical properties. For these reasons, phosphorus corroles represent a class of interesting compounds to be exploited in the field of material science or for biomedical investigations and the definition of synthetic pathways for their functionalization is an important step to optimize their properties for various applications. We report here the reactivity of the phosphorus complex of 5,10,15-tritolylcorrole in the nitration or bromination reaction. Both these attempts were successful, allowing the preparation of substituted phosphorus corroles, which can be used as intermediates of more complex architectures endowed with useful properties. Furthermore, the crystallographic characterization of both complexes shows that they have an unusual ruffled geometry of the corrole core, a conformation that has not been considered possible for such a macrocycle.

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

    DOEpatents

    Guilinger, Terry R.

    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.

  3. Global baseline data on phosphorus pollution of large lakes

    NASA Astrophysics Data System (ADS)

    Fink, Gabriel; Flörke, Martina; Alcamo, Joseph

    2016-04-01

    Lakes are exposed to harmful eutrophication which is the most concerning water quality issue on global scale. Eutrophication is caused by phosphorous pollution in most lakes. Hence, global consistent base line data on phosphorus loadings are needed to assess future sustainable development. We used the modeling framework WaterGAP3 to calculate present total phosphorus loadings to the world's largest lakes. Estimates of modeled total phosphorus (TP) loadings as well as the contributions of different sectors were successfully validated against measured data. Based on these findings, annual total phosphorus loadings to lakes were calculated for diffuse and point sources according to the different sectors domestic, manufacturing, urban surface runoff, agriculture and background for the time period 1990 to 2010. Our results show high phosphorus loadings into lakes in southern latitudes. On global average, industrial fertilizer is the main anthropogenic source while background loadings are low in comparison. Nevertheless, both features indicate a high potential to reduce the exposure to eutrophication in lakes which are faced with high phosphor inputs. The global average of TP loadings was 7% higher in the time period 2005-2010 than in the period 1990-1995. The global average in 2005-2010 results from an increase in TP loadings of 79% in South America, which was dampened by a decrease in Europe, North America, and Asia. Chinese lakes were exposed to massive increasing phosphorus loadings, too. Both increasing and decreasing trends are caused primarily by changing industrial fertilizer application rates. In conclusion, this study provides a consistent and model based synopsis of global trends and sources of phosphorus loadings to large lakes. The estimates of phosphorus pollution of lakes present a basis for assessing and managing the global eutrophication problem.

  4. The removal of phosphorus during wastewater treatment: a review.

    PubMed

    Yeoman, S; Stephenson, T; Lester, J N; Perry, R

    1988-01-01

    Phosphorus removal from wastewater can be achieved either through chemical removal, advanced biological treatment or a combination of both. The chemical removal of phosphorus involves the addition of calcium, iron and aluminium salts to achieve phosphorus precipitation by various mechanisms which are discussed. In addition, the effects of operating conditions, especially wastewater characteristics; sludge production in terms of quality and quantity; optimisation of chemical use and re-use; points of chemical addition combined with biological treatment; alternative chemical/physical treatments and examples of full-scale applications are also reviewed. Biological phosphorus removal is dependent upon the uptake of phosphorus in excess of normal bacterial metabolic requirements and is proposed as an alternative to chemical treatment. Early developments and the postulated removal mechanisms are reviewed; these include either natural chemical precipitation, enhanced biological removal, or a combination of both. The nature of excess biological phosphorus removal in activated sludge wastewater treatment plants is evaluated, considering various operating parameters, bacteriology and process designs. PMID:15092663

  5. 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.

  6. Balancing nutrition and serum phosphorus in maintenance dialysis.

    PubMed

    Fouque, Denis; Horne, Rob; Cozzolino, Mario; Kalantar-Zadeh, Kamyar

    2014-07-01

    Elevated serum phosphorus levels are common in patients with chronic kidney disease and are associated with heart and vascular disease, conditions that in turn are associated with increased mortality. Accurately managing phosphorus intake by restricting dietary protein alone can prove challenging because protein from different sources can contain varying amounts of available phosphorus. Additives used in processed foods frequently are high in inorganic phosphorus, which is readily absorbed, compounding this difficulty. Recent evidence suggests that dietary protein restriction in some cases may do more harm than good in some patients treated with maintenance hemodialysis because protein restriction can lead to protein-energy wasting, which is associated with increased mortality. Accordingly, phosphorus binders are important for managing hyperphosphatemia in dialysis patients. Managing hyperphosphatemia in patients with late-stage chronic kidney disease requires an individualized approach, involving a combination of adequate dietary advice, phosphate-binder use, and adjustments to dialysis prescription. We speculate that increased use of phosphate binders could allow patients to eat more protein-rich foods and that communicating this to patients might increase their perception of their need for phosphate binders, providing an incentive to improve adherence. The aim of this review is to discuss the challenges involved in maintaining adequate nutrition while controlling phosphorus levels in patients on maintenance hemodialysis therapy.

  7. Content and distribution of different phosphorus forms in broiler chickens.

    PubMed

    Li, X-K; Wang, J-Z; Zhang, C-H; Li, X; Tang, C-H

    2016-04-01

    To understand the background value of phosphorus in chickens, the quantitative distribution of different phosphorus forms, including total phosphorus (TP), free phosphate (FP) and phospholipid (PL), in viscera, blood and bones of broiler chickens was investigated. Results showed that phosphorus contents exhibited significant differences in different parts of chickens. TP content of breast and thigh meat was over 5.0 g/kg, in which most of the phosphorus was in the form of water-soluble phosphates. TP content in viscera was higher than that in meat, and spleen was observed to contain the highest amount of phosphorus (10.0 g/kg). In all tested organs, FP and PL contents in liver were the highest, ranging between 1207-1989 and 81-369 mg/kg respectively. TP content in chicken bone was in the range of 52,716-136,643 mg/kg, and FP content in the bone was relatively lower than that in chicken meat. PMID:26189915

  8. Calcium and phosphorus requirements of breeding bobwhite quail

    USGS Publications Warehouse

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

    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.

  9. Global phosphorus scarcity: identifying synergies for a sustainable future.

    PubMed

    Neset, Tina-Simone S; Cordell, Dana

    2012-01-15

    Global food production is dependent on constant inputs of phosphorus. In the current system this phosphorus is not predominantly derived from organic recycled waste, but to a large degree from phosphate-rock based mineral fertilisers. However, phosphate rock is a finite resource that cannot be manufactured. Our dependency therefore needs to be addressed from a sustainability perspective in order to ensure global food supplies for a growing global population. The situation is made more urgent by predictions that, for example, the consumption of resource intensive foods and the demand for biomass energy will increase. The scientific and societal debate has so far been focussed on the exact timing of peak phosphorus and on when the total depletion of the global reserves will occur. Even though the timing of these events is important, all dimensions of phosphorus scarcity need to be addressed in a manner which acknowledges linkages to other sustainable development challenges and which takes into consideration the synergies between different sustainability measures. Many sustainable phosphorus measures have positive impacts on other challenges; for example, shifting global diets to more plant-based foods would not only reduce global phosphorus consumption, but also reduce greenhouse gas emissions, reduce nitrogen fertiliser demand and reduce water consumption.

  10. Thermal conduction in single-layer black phosphorus: highly anisotropic?

    PubMed

    Jiang, Jin-Wu

    2015-02-01

    The single-layer black phosphorus is characteristic for its puckered structure, which has led to distinct anisotropy in its optical, electronic, and mechanical properties. We use the non-equilibrium Green's function approach and the first-principles method to investigate the thermal conductance for single-layer black phosphorus in the ballistic transport regime, in which the phonon-phonon scattering is neglected. We find that the anisotropy in the thermal conduction is very weak for the single-layer black phosphorus--the difference between two in-plane directions is less than 4%. Our phonon calculations disclose that the out-of-plane acoustic phonon branch has lower group velocities in the direction perpendicular to the pucker, as the black phosphorus is softer in this direction, leading to a weakening effect for the thermal conductance in the perpendicular direction. However, the longitudinal acoustic phonon branch behaves abnormally; i.e., the group velocity of this phonon branch is higher in the perpendicular direction, although the single-layer black phosphorus is softer in this direction. The abnormal behavior of the longitudinal acoustic phonon branch is closely related to the highly anisotropic Poisson's ratio in the single-layer black phosphorus. As a result of the counteraction between the out-of-plane phonon mode and the in-plane phonon modes, the thermal conductance in the perpendicular direction is weaker than the parallel direction, but the anisotropy is pretty small.

  11. 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

  12. Management of natural and added dietary phosphorus burden in kidney disease.

    PubMed

    Cupisti, Adamasco; Kalantar-Zadeh, Kamyar

    2013-03-01

    Phosphorus retention occurs from higher dietary phosphorus intake relative to its renal excretion or dialysis removal. In the gastrointestinal tract the naturally existing organic phosphorus is only partially (∼60%) absorbable; however, this absorption varies widely and is lower for plant-based phosphorus including phytate (<40%) and higher for foods enhanced with inorganic phosphorus-containing preservatives (>80%). The latter phosphorus often remains unrecognized by patients and health care professionals, even though it is widely used in contemporary diets, in particular, low-cost foods. In a nonenhanced mixed diet, digestible phosphorus correlates closely with total protein content, making protein-rich foods a main source of natural phosphorus. Phosphorus burden is limited more appropriately in predialysis patients who are on a low-protein diet (∼0.6 g/kg/d), whereas dialysis patients who require higher protein intake (∼1.2 g/kg/d) are subject to a higher dietary phosphorus load. An effective and patient-friendly approach to reduce phosphorus intake without depriving patients of adequate proteins is to educate patients to avoid foods with high phosphorus relative to protein such as egg yolk and those with high amounts of phosphorus-based preservatives such as certain soft drinks and enhanced cheese and meat. Phosphorus rich foods should be prepared by boiling, which reduces phosphorus as well as sodium and potassium content, or by other types of cooking-induced demineralization. The dose of phosphorus-binding therapy should be adjusted separately for the amount and absorbability of phosphorus in each meal. Dietician counseling to address the emerging aspects of dietary phosphorus management is instrumental for achieving a reduction of phosphorus load. PMID:23465504

  13. Management of natural and added dietary phosphorus burden in kidney disease.

    PubMed

    Cupisti, Adamasco; Kalantar-Zadeh, Kamyar

    2013-03-01

    Phosphorus retention occurs from higher dietary phosphorus intake relative to its renal excretion or dialysis removal. In the gastrointestinal tract the naturally existing organic phosphorus is only partially (∼60%) absorbable; however, this absorption varies widely and is lower for plant-based phosphorus including phytate (<40%) and higher for foods enhanced with inorganic phosphorus-containing preservatives (>80%). The latter phosphorus often remains unrecognized by patients and health care professionals, even though it is widely used in contemporary diets, in particular, low-cost foods. In a nonenhanced mixed diet, digestible phosphorus correlates closely with total protein content, making protein-rich foods a main source of natural phosphorus. Phosphorus burden is limited more appropriately in predialysis patients who are on a low-protein diet (∼0.6 g/kg/d), whereas dialysis patients who require higher protein intake (∼1.2 g/kg/d) are subject to a higher dietary phosphorus load. An effective and patient-friendly approach to reduce phosphorus intake without depriving patients of adequate proteins is to educate patients to avoid foods with high phosphorus relative to protein such as egg yolk and those with high amounts of phosphorus-based preservatives such as certain soft drinks and enhanced cheese and meat. Phosphorus rich foods should be prepared by boiling, which reduces phosphorus as well as sodium and potassium content, or by other types of cooking-induced demineralization. The dose of phosphorus-binding therapy should be adjusted separately for the amount and absorbability of phosphorus in each meal. Dietician counseling to address the emerging aspects of dietary phosphorus management is instrumental for achieving a reduction of phosphorus load.

  14. 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 π 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.

  15. Heterotrophic bacteria from an extremely phosphate-poor lake have conditionally reduced phosphorus demand and utilize diverse sources of phosphorus.

    PubMed

    Yao, Mengyin; Elling, Felix J; Jones, CarriAyne; Nomosatryo, Sulung; Long, Christopher P; Crowe, Sean A; Antoniewicz, Maciek R; Hinrichs, Kai-Uwe; Maresca, Julia A

    2016-02-01

    Heterotrophic Proteobacteria and Actinobacteria were isolated from Lake Matano, Indonesia, a stratified, ferruginous (iron-rich), ultra-oligotrophic lake with phosphate concentrations below 50 nM. Here, we describe the growth of eight strains of heterotrophic bacteria on a variety of soluble and insoluble sources of phosphorus. When transferred to medium without added phosphorus (P), the isolates grow slowly, their RNA content falls to as low as 1% of cellular dry weight, and 86-100% of the membrane lipids are replaced with amino- or glycolipids. Similar changes in lipid composition have been observed in marine photoautotrophs and soil heterotrophs, and similar flexibility in phosphorus sources has been demonstrated in marine and soil-dwelling heterotrophs. Our results demonstrate that heterotrophs isolated from this unusual environment alter their macromolecular composition, which allows the organisms to grow efficiently even in their extremely phosphorus-limited environment. PMID:26415900

  16. Wet deposition of phosphorus in Florida

    NASA Astrophysics Data System (ADS)

    Pollman, C. D.; Landing, W. M.; Perry, J. J.; Fitzpatrick, T.

    Wet deposition of phosphorus was measured at 10 sites across Florida originally established as part of the Florida Atmospheric Mercury Study conducted between 1992 and 1996. Monthly integrated samples were collected and analyzed using a total analytical protocol that incorporated "clean lab" conditions for sample equipment preparation and Aerochem Metrics collectors modified for suitability to use for ultra-trace elements. Samples also were collected aboard 15 m towers to minimize any influence on measured deposition by insects, etc., and locally originating particles that do not contribute to true net deposition. Extensive replication of samples in the field was conducted (ca. 83%). The average absolute difference between replicates was 16.2%, with a median absolute difference of 9.5%. Replicate precision was poorest for concentrations above 0.080 mg P l -1, suggesting that concentrations above this level are contaminated. The wet deposition concentrations and fluxes of phosphorus measured in this study are appreciably lower than those reported by previous investigators for wet deposition in Florida, and lie at the lower end of measurements reported in the recent literature. For example, the volume weighted mean concentration and flux for wet deposition across all our study sites averaged 0.005 mg P l -1 and 7.5 mg P m -2 yr -1, respectively, which is approximately 50% and 32% lower than that reported by Hendry et al. (1981 in Atmospheric Pollutants in Natural Waters. Ann Arbor Science, Ann Arbor. MI, pp. 199-215). Our lower measurements likely reflect three factors: (1) the ultra-trace element sampling and analytical protocols; (2) improved collector design to eliminate sampling artifacts (e.g., splash-off contamination and transfer of contaminants from the dry bucket); and (3) placement of collectors off the ground surface. Lower VWM concentrations were observed near the Florida coast; otherwise, strong spatial patterns across the state were absent. Seasonal

  17. Evaluation of total phosphorus and total nitrogen methods in pulp mill effluents.

    PubMed

    Cook, D L; Frum, N L

    2004-01-01

    Under the Clean Water Action Plan, the US Environmental Protection Agency is requiring states to establish numeric criteria for phosphorus and nitrogen. In preparation for the development of nutrient criteria NCASI undertook a research project to conduct a comparative study of methods for the determination of total phosphorus and total nitrogen in pulp and paper mill matrices. This paper presents results of a single laboratory method evaluation and comparative study of digestion techniques and analytical methods for the determination of total phosphorus (TP) and total nitrogen (TN) in pulp and paper mill secondary treated effluents. Analytical methods included EPA Methods 365.2 and 365.4 for TP. TN and total kjeldahl nitrogen (TKN) methods included EPA Methods 351.2, 351.4, and 353.2. Examinations of sample preservation and storage stability were conducted. Substitution of mercuric sulfate with copper sulfate during block digestion resulted in higher blank levels and method detection limits. TP measurements using EPA Method 365.4 (autoanalyzer) were found to be accurate with a positive bias as determined using matrix spike experiments. Sample digestion by acidic persulfate oxidation or mercuric sulfate block digestion in conjunction with EPA Method 365.4 yielded low blank levels (averages of 0.01 and 0.02 mg/L, respectively), precision of 2.1 and 2.4% relative standard deviations, respectively, and accuracy expressed as an average recovery (%R) of 117% for both. EPA Method 351.2 (autoanalyzer) was more precise than EPA Method 351.4 (ammonia probe). Accuracy (%R) for EPA Method 351.2 ranged from 81 to 95%, depending on the digestion technique applied, and was 55% when EPA Method 351.4 was utilized. Investigation of a method utilizing basic to acidic persulfate oxidation for the simultaneous determination of TN and TP using only two analytical techniques was found to be effective at concentrations above 1 mg/L in pulp mill effluents.

  18. A High Phosphorus Diet Affects Lipid Metabolism in Rat Liver: A DNA Microarray Analysis.

    PubMed

    Chun, Sunwoo; Bamba, Takeshi; Suyama, Tatsuya; Ishijima, Tomoko; Fukusaki, Eiichiro; Abe, Keiko; Nakai, Yuji

    2016-01-01

    A high phosphorus (HP) diet causes disorders of renal function, bone metabolism, and vascular function. We previously demonstrated that DNA microarray analysis is an appropriate method to comprehensively evaluate the effects of a HP diet on kidney dysfunction such as calcification, fibrillization, and inflammation. We reported that type IIb sodium-dependent phosphate transporter is significantly up-regulated in this context. In the present study, we performed DNA microarray analysis to investigate the effects of a HP diet on the liver, which plays a pivotal role in energy metabolism. DNA microarray analysis was performed with total RNA isolated from the livers of rats fed a control diet (containing 0.3% phosphorus) or a HP diet (containing 1.2% phosphorus). Gene Ontology analysis of differentially expressed genes (DEGs) revealed that the HP diet induced down-regulation of genes involved in hepatic amino acid catabolism and lipogenesis, while genes related to fatty acid β-oxidation process were up-regulated. Although genes related to fatty acid biosynthesis were down-regulated in HP diet-fed rats, genes important for the elongation and desaturation reactions of omega-3 and -6 fatty acids were up-regulated. Concentrations of hepatic arachidonic acid and eicosapentaenoic acid were increased in HP diet-fed rats. These essential fatty acids activate peroxisome proliferator-activated receptor alpha (PPARα), a transcription factor for fatty acid β-oxidation. Evaluation of the upstream regulators of DEGs using Ingenuity Pathway Analysis indicated that PPARα was activated in the livers of HP diet-fed rats. Furthermore, the serum concentration of fibroblast growth factor 21, a hormone secreted from the liver that promotes fatty acid utilization in adipose tissue as a PPARα target gene, was higher (p = 0.054) in HP diet-fed rats than in control diet-fed rats. These data suggest that a HP diet enhances energy expenditure through the utilization of free fatty acids

  19. A High Phosphorus Diet Affects Lipid Metabolism in Rat Liver: A DNA Microarray Analysis

    PubMed Central

    Chun, Sunwoo; Bamba, Takeshi; Suyama, Tatsuya; Ishijima, Tomoko; Fukusaki, Eiichiro; Abe, Keiko; Nakai, Yuji

    2016-01-01

    A high phosphorus (HP) diet causes disorders of renal function, bone metabolism, and vascular function. We previously demonstrated that DNA microarray analysis is an appropriate method to comprehensively evaluate the effects of a HP diet on kidney dysfunction such as calcification, fibrillization, and inflammation. We reported that type IIb sodium-dependent phosphate transporter is significantly up-regulated in this context. In the present study, we performed DNA microarray analysis to investigate the effects of a HP diet on the liver, which plays a pivotal role in energy metabolism. DNA microarray analysis was performed with total RNA isolated from the livers of rats fed a control diet (containing 0.3% phosphorus) or a HP diet (containing 1.2% phosphorus). Gene Ontology analysis of differentially expressed genes (DEGs) revealed that the HP diet induced down-regulation of genes involved in hepatic amino acid catabolism and lipogenesis, while genes related to fatty acid β-oxidation process were up-regulated. Although genes related to fatty acid biosynthesis were down-regulated in HP diet-fed rats, genes important for the elongation and desaturation reactions of omega-3 and -6 fatty acids were up-regulated. Concentrations of hepatic arachidonic acid and eicosapentaenoic acid were increased in HP diet-fed rats. These essential fatty acids activate peroxisome proliferator-activated receptor alpha (PPARα), a transcription factor for fatty acid β-oxidation. Evaluation of the upstream regulators of DEGs using Ingenuity Pathway Analysis indicated that PPARα was activated in the livers of HP diet-fed rats. Furthermore, the serum concentration of fibroblast growth factor 21, a hormone secreted from the liver that promotes fatty acid utilization in adipose tissue as a PPARα target gene, was higher (p = 0.054) in HP diet-fed rats than in control diet-fed rats. These data suggest that a HP diet enhances energy expenditure through the utilization of free fatty acids

  20. Bioavailability of Phosphorus in Two Cultivars of Pea for Broiler Chicks.

    PubMed

    Woyengo, T A; Emiola, I A; Kim, I H; Nyachoti, C M

    2016-03-01

    The aim was to determine the relative bioavailability of phosphorus (P) in peas for 21-day old broiler chickens using slope-ratio assay. One hundred and sixty eight male Ross 308 broiler chicks were divided into 42 groups 4 balanced for body weight and fed 7 diets in a completely randomized design (6 groups/diet) from day 1 to 21 of age. The diets were a corn-soybean meal basal diet, and the corn-soybean meal basal diet to which monosodium phosphate, brown- or yellow-seeded pea was added at the expense of cornstarch to supply 0.5% or 1% total phosphorus. Monosodium phosphate was included as a reference, and hence the estimated bioavailability of P in pea cultivars was relative to that in the monosodium phosphate. Birds and feed were weighed weekly and on d 21 they were killed to obtain tibia. The brown-seeded pea contained 23.4% crude protein, 0.47% P, whereas the yellow-seeded pea contained 24.3% crude protein and 0.38% P. Increasing dietary P supply improved (p<0.05) chick body weight gain and tibia ash and bone density. The estimated relative bioavailability of p values for brown- and yellow-seeded peas obtained using final body weight, average daily gain, tibia ash, and bone mineral density were 31.5% and 36.2%, 35.6% and 37.3%, 23.0% and 5.60%, and 40.3% and 30.3%, respectively. The estimated relative bioavailability of p values for brown- and yellow-seeded peas did not differ within each of the response criteria measured in this study. In conclusion, the relative bioavailability of P in pea did not differ depending on the cultivar (brown- vs yellow-seed). However, the relative bioavailability of P in pea may vary depending on the response criterion used to measure the bioavailability. PMID:26950872

  1. Bioavailability of Phosphorus in Two Cultivars of Pea for Broiler Chicks

    PubMed Central

    Woyengo, T. A.; Emiola, I. A.; Kim, I. H.; Nyachoti, C. M.

    2016-01-01

    The aim was to determine the relative bioavailability of phosphorus (P) in peas for 21-day old broiler chickens using slope-ratio assay. One hundred and sixty eight male Ross 308 broiler chicks were divided into 42 groups 4 balanced for body weight and fed 7 diets in a completely randomized design (6 groups/diet) from day 1 to 21 of age. The diets were a corn-soybean meal basal diet, and the corn-soybean meal basal diet to which monosodium phosphate, brown- or yellow-seeded pea was added at the expense of cornstarch to supply 0.5% or 1% total phosphorus. Monosodium phosphate was included as a reference, and hence the estimated bioavailability of P in pea cultivars was relative to that in the monosodium phosphate. Birds and feed were weighed weekly and on d 21 they were killed to obtain tibia. The brown-seeded pea contained 23.4% crude protein, 0.47% P, whereas the yellow-seeded pea contained 24.3% crude protein and 0.38% P. Increasing dietary P supply improved (p<0.05) chick body weight gain and tibia ash and bone density. The estimated relative bioavailability of p values for brown- and yellow-seeded peas obtained using final body weight, average daily gain, tibia ash, and bone mineral density were 31.5% and 36.2%, 35.6% and 37.3%, 23.0% and 5.60%, and 40.3% and 30.3%, respectively. The estimated relative bioavailability of p values for brown- and yellow-seeded peas did not differ within each of the response criteria measured in this study. In conclusion, the relative bioavailability of P in pea did not differ depending on the cultivar (brown- vs yellow-seed). However, the relative bioavailability of P in pea may vary depending on the response criterion used to measure the bioavailability. PMID:26950872

  2. Bioavailability of Phosphorus in Two Cultivars of Pea for Broiler Chicks.

    PubMed

    Woyengo, T A; Emiola, I A; Kim, I H; Nyachoti, C M

    2016-03-01

    The aim was to determine the relative bioavailability of phosphorus (P) in peas for 21-day old broiler chickens using slope-ratio assay. One hundred and sixty eight male Ross 308 broiler chicks were divided into 42 groups 4 balanced for body weight and fed 7 diets in a completely randomized design (6 groups/diet) from day 1 to 21 of age. The diets were a corn-soybean meal basal diet, and the corn-soybean meal basal diet to which monosodium phosphate, brown- or yellow-seeded pea was added at the expense of cornstarch to supply 0.5% or 1% total phosphorus. Monosodium phosphate was included as a reference, and hence the estimated bioavailability of P in pea cultivars was relative to that in the monosodium phosphate. Birds and feed were weighed weekly and on d 21 they were killed to obtain tibia. The brown-seeded pea contained 23.4% crude protein, 0.47% P, whereas the yellow-seeded pea contained 24.3% crude protein and 0.38% P. Increasing dietary P supply improved (p<0.05) chick body weight gain and tibia ash and bone density. The estimated relative bioavailability of p values for brown- and yellow-seeded peas obtained using final body weight, average daily gain, tibia ash, and bone mineral density were 31.5% and 36.2%, 35.6% and 37.3%, 23.0% and 5.60%, and 40.3% and 30.3%, respectively. The estimated relative bioavailability of p values for brown- and yellow-seeded peas did not differ within each of the response criteria measured in this study. In conclusion, the relative bioavailability of P in pea did not differ depending on the cultivar (brown- vs yellow-seed). However, the relative bioavailability of P in pea may vary depending on the response criterion used to measure the bioavailability.

  3. 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 Σ5(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.

  4. The Behavior of Phosphorus During Reduction and Carburization of High-Phosphorus Oolitic Hematite with H2 and CH4

    NASA Astrophysics Data System (ADS)

    Wang, Henghui; Li, Guangqiang; Yang, Jian; Ma, Jianghua; Khan, Babar Shahzad

    2016-08-01

    High-phosphorus oolitic hematite has not been widely utilized due to high content of phosphorus. Ca3(PO4)2 is the main component containing phosphorus in high-phosphorus oolitic hematite. In the present work, the thermodynamics was studied for Ca3(PO4)2 reduction by H2 gas and then carburization by CH4 gas. The results show that phosphorous in Ca3(PO4)2 cannot be reduced from gangue during the reduction of hematite and the formation of iron carbide at the temperature from 923 K to 1073 K (650 °C to 800 °C), in H2 and CH4 atmosphere. Reduction and carburization experiments were carried out. And phosphorus in reduced and carburized specimens was analyzed by EDS and wet chemical method. The results confirmed that phosphorous cannot be reduced during the preparation of iron carbide from this iron ore. So the metallic iron or iron carbide can be prepared without the reduction of phosphorous at relatively low temperature, which can be a new route of utilizing high-phosphorus oolitic hematite. After fine milling-magnetic separation, the 99.47 pct of Fe3C-containing material was recovered, but the dephosphorization rate reached to 19.37 pct only.

  5. 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.

  6. Multipurpose Black-Phosphorus/hBN Heterostructures.

    PubMed

    Constantinescu, Gabriel C; Hine, Nicholas D M

    2016-04-13

    Black phosphorus (BP) has recently emerged as a promising semiconducting two-dimensional material. However, its viability is threatened by its instability in ambient conditions and by the significant decrease of its band gap in multilayers. We show that one could solve all the aforementioned problems by interfacing BP with hexagonal boron nitride (hBN). To this end, we simulate large, rotated hBN/BP interfaces using linear-scaling density functional theory. We predict that hBN-encapsulation preserves the main electronic properties of the BP monolayer, while hBN spacers can be used to counteract the band gap reduction in stacked BP. Finally, we propose a model for a tunneling field effect transistor (TFET) based on hBN-spaced BP bilayers. Such BP TFETs would sustain both low-power and fast-switching operations, including negative differential resistance behavior with peak-to-valley ratios of the same order of magnitude as those encountered in transition metal dichalcogenide TFETs. PMID:27028122

  7. 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.

  8. Phosphorus component in AnnAGNPS

    USGS Publications Warehouse

    Yuan, Y.; Bingner, R.L.; Theurer, F.D.; Rebich, R.A.; Moore, P.A.

    2005-01-01

    The USDA Annualized Agricultural Non-Point Source Pollution model (AnnAGNPS) has been developed to aid in evaluation of watershed response to agricultural management practices. Previous studies have demonstrated the capability of the model to simulate runoff and sediment, but not phosphorus (P). The main purpose of this article is to evaluate the performance of AnnAGNPS on P simulation using comparisons with measurements from the Deep Hollow watershed of the Mississippi Delta Management Systems Evaluation Area (MDMSEA) project. A sensitivity analysis was performed to identify input parameters whose impact is the greatest on P yields. Sensitivity analysis results indicate that the most sensitive variables of those selected are initial soil P contents, P application rate, and plant P uptake. AnnAGNPS simulations of dissolved P yield do not agree well with observed dissolved P yield (Nash-Sutcliffe coefficient of efficiency of 0.34, R2 of 0.51, and slope of 0.24); however, AnnAGNPS simulations of total P yield agree well with observed total P yield (Nash-Sutcliffe coefficient of efficiency of 0.85, R2 of 0.88, and slope of 0.83). The difference in dissolved P yield may be attributed to limitations in model simulation of P processes. Uncertainties in input parameter selections also affect the model's performance.

  9. 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.

  10. 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 μm), while the mass of P is distributed predominantly between sediment and suspended (<25 μm) 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.

  11. Dirac fermions in blue-phosphorus

    NASA Astrophysics Data System (ADS)

    Li, Yuanchang; Chen, Xiaobin

    2014-12-01

    We propose that Dirac cones can be engineered in phosphorene with fourfold-coordinated phosphorus atoms. The key is to separate the energy levels of the in-plane (s, px, and py) and out-of-plane (pz) oribtals through the sp2 configuration, yielding respective σ- and π-character Dirac cones, and then quench the latter. As a proof-of-principle study, we create σ-character Dirac cones in hydrogenated and fluorinated phosphorene with a honeycomb lattice. The obtained Dirac cones are at K-points, slightly anisotropic, with Fermi velocities of 0.91 and 1.23 times that of graphene along the ΓK and KM direction, and maintain good linearity up to ˜2 eV for holes. A substantive advantage of a σ-character Dirac cone is its convenience in tuning the Dirac gap via in-plane strain. Our findings pave the way for development of high-performance electronic devices based on Dirac materials.

  12. 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.

  13. 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 μg 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.

  14. Multipurpose Black-Phosphorus/hBN Heterostructures.

    PubMed

    Constantinescu, Gabriel C; Hine, Nicholas D M

    2016-04-13

    Black phosphorus (BP) has recently emerged as a promising semiconducting two-dimensional material. However, its viability is threatened by its instability in ambient conditions and by the significant decrease of its band gap in multilayers. We show that one could solve all the aforementioned problems by interfacing BP with hexagonal boron nitride (hBN). To this end, we simulate large, rotated hBN/BP interfaces using linear-scaling density functional theory. We predict that hBN-encapsulation preserves the main electronic properties of the BP monolayer, while hBN spacers can be used to counteract the band gap reduction in stacked BP. Finally, we propose a model for a tunneling field effect transistor (TFET) based on hBN-spaced BP bilayers. Such BP TFETs would sustain both low-power and fast-switching operations, including negative differential resistance behavior with peak-to-valley ratios of the same order of magnitude as those encountered in transition metal dichalcogenide TFETs.

  15. 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

  16. Expert systems guide biological phosphorus removal

    SciTech Connect

    Krichten, D.J.; Wilson, K.D.; Tracy, K.D. )

    1991-10-01

    There is a large body of knowledge regarding optimum control strategies for new secondary wastewater treatment technology using an anaerobic selector to provide biological phosphorus removal. However, because the selector technology is new and the concepts differ somewhat from those used in conventional activated sludge wastewater treatment, a method of communicating this knowledge to plant operators is needed. Traditional methods such as classroom training and operating manuals are of limited effectiveness. The commonplace availability and low cost of the personal computer (PC) makes it practical to use a computer program to communicate the type of information required to control a wastewater treatment plant. Knowledge-based systems technology, commonly referred to as expert systems (ES) technology, is easy to use, provides useful information regarding a consistent control strategy, relieves the anxiety associated with learning a new process,' and provides instruction for inexperienced personnel. ES technology does not require special formatted input and is therefore easily accessible. All information required by the program is readily available through routine laboratory analysis, common plant instrumentation, or direct user observation. The program was designed for all levels of computer users and will run on all IBM-compatible or Apple MacIntosh systems.

  17. 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.

  18. 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

  19. 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.

  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. Phosphorus in lacustrine groundwater discharge drives eutrophication

    NASA Astrophysics Data System (ADS)

    Meinikmann, Karin; Hupfer, Michael; Lewandowski, Jörg

    2016-04-01

    Lake eutrophication has long been mainly associated with phosphorus (P) inputs from overland flow. Our work gives evidence that also groundwater can carry significant loads of dissolved P. We quantified P loads from groundwater to Lake Arendsee using near-shore measurements of P concentrations at a high spatial resolution and volume fluxes of lacustrine groundwater discharge (LGD) derived from a previous study. Results show that LGD accounts for more than 50% of the overall external P load, thus fueling the eutrophication of the lake. Several different approaches of groundwater sampling (groundwater observation wells, temporary piezometers, and domestic wells) reveal a broad spatial heterogeneity of P concentrations in the subsurface catchment of the lake. The highest P concentrations (above 4 mg/L) were found below a settled area along the southern lake shore. Contrary to expectations, other parameters (dissolved iron, ammonium, etc.) were not correlated with P, indicating that natural processes are superimposed by heavy contaminations. Both the intensity of the contamination and its proximity to the lake inhibit nutrient retention within vadose zone and aquifer and allow significant P loads to be discharged into the lake.

  2. 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.

  3. Phosphorus removal using novel crystallisation technology.

    PubMed

    Wood, K; Wood, G; Prokop, D; Lewyille, F

    2006-01-01

    A soy protein manufacturing facility was faced with the challenge of reducing its effluent phosphorus (P) content from 20-50 mg L(-1) down to <2 mg L(-1) total P without increasing soluble salt levels to comply with discharge and receiving water requirements. A number of biological and chemical P removal technologies previously evaluated either failed to achieve the new standards or would have produced prohibitive amounts of residual sludge and unacceptably high effluent salt concentrations. Lime precipitation, utilising a novel crystallisation technology, was demonstrated through on-site pilot testing to meet the process objectives. It is capable of achieving the required P removal at pH 10 while not increasing soluble salts and producing rapid settling and filterable particles. Also, minimal carbonate removal was observed with residual solids generation being only 40% of a complete lime softening reaction. This paper describes the technical evaluation that led to the full-scale treatment system that was put into operation in late 2005. PMID:16889253

  4. 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.

  5. Building 21: B21 Philadelphia

    ERIC Educational Resources Information Center

    EDUCAUSE, 2015

    2015-01-01

    As a non-selective neighborhood high school in the School District of Philadelphia, B21's mission is to empower networks of learners to connect with their passions and build agency to impact their world. Building 21 is organized into studios, workshops, and advisories. Core studios engage students in project-based learning. Blended learning…

  6. Geochemical forms and seasonal variations of phosphorus in surface sediments of the East China Sea shelf

    NASA Astrophysics Data System (ADS)

    Zhou, Fengxia; Gao, Xuelu; Yuan, Huamao; Song, Jinming; Chen, Chen-Tung Arthur; Lui, Hon-Kit; Zhang, Yong

    2016-07-01

    Geochemical characteristics of phosphorus (P) in the surface sediments of the East China Sea shelf (ECSS) were studied in spring and autumn, 2014. Distributions, seasonal variations, transformations and their influencing factors were discussed. Besides, burial fluxes of P in different seasons were also calculated. Five operationally defined forms of P, namely exchangeable or loosely sorbed P (Ads-P), iron-bound P (Fe-P), authigenic P (Au-P), detrital apatite plus other inorganic P (De-P) and organic P (OP), were obtained using a sequential extraction procedure. Generally, the concentrations of Ads-P, Fe-P, Au-P and OP decreased seaward and the concentrations of De-P increased seaward in both seasons. In spring, the average concentrations of Ads-P, Fe-P, Au-P, De-P and OP were 13.8 ± 5.0, 21.9 ± 7.6, 148.5 ± 44.5, 153.1 ± 55.8 and 91.7 ± 21.5 μg g- 1, respectively. The corresponding concentrations in autumn were 11.4 ± 4.3, 20.0 ± 10.9, 170.4 ± 53.6, 225.6 ± 101.7 and 77.1 ± 33.9 μg g- 1, respectively. The average percentages of P fractions in total P (TP) in spring and autumn were both in the order: De-P > Au-P > OP > Fe-P > Ads-P. The average concentrations of Bio-available P (Bio-P) were 127.4 ± 31.4 μg g- 1 in spring and 108.5 ± 47.2 μg g- 1 in autumn, accounting for 29.8% ± 7.3% and 21.5% ± 8.2% of corresponding TP, respectively. Seasonal variations of the primary production, hydrodynamic conditions, hypoxia and other environmental conditions were responsible for the seasonal variations of different phosphorus forms. The calculation of burial fluxes reflected that, in most parts of the studied area, TP had relative high burial fluxes in autumn, while Bio-P had relatively high burial fluxes in spring. The burial fluxes of other phosphorus forms also showed different seasonal variations in different parts of the studied area.

  7. Positron probing of phosphorus-vacancy complexes in silicon irradiated with 15 MeV protons

    NASA Astrophysics Data System (ADS)

    Arutyunov, N.; Emtsev, V.; Krause-Rehberg, R.; Elsayed, M.; Kessler, C.; Kozlovski, V.; Oganesyan, G.

    2015-06-01

    Defects in phosphorus-doped silicon samples of floating-zone material, n-FZ-Si(P), produced under irradiation with 15 MeV protons at room temperature are studied by positron annihilation lifetime spectroscopy over the temperature range of ∼ 30 K - 300 K and by low- temperature Hall effect measurements. After annealing of E-centersand divacancies, we detected for the first time high concentrations of positron traps which had not been observed earlier. These defects are isochronally annealed over the temperature interval of ∼ 320 °C - 700 °C they manifest themselves as electrically neutral deep donor centersin the material of n-type. A long-lived component of the positron lifetime, τ2(I2 < 60%) ∼ 280 ps, attributed to these centers, suggests a relaxed configuration involving two vacancies. The enthalpy and entropy of annealing of these centersare Ea ∼ 1.05(0.21) eV and ΔSm ≈ 3.1(0.6)kB, respectively. It is argued that the microstructure of the defect consists of two vacancies, VV, and one atom of phosphorus, P. The split configuration of the VPV complex is shortly discussed.

  8. Microbial selection on enhanced biological phosphorus removal systems fed exclusively with glucose.

    PubMed

    Begum, Shamim A; Batista, Jacimaria R

    2012-05-01

    The microbial selection on an enhanced biological phosphorus removal (EBPR) system was investigated in a laboratory-scale sequencing batch reactor fed exclusively with glucose as the carbon source. Fluorescence In Situ Hybridization analysis was performed to target two polyphosphate accumulating organisms (PAOs) (i.e., Candidatus Accumulibacter phosphatis and Microlunatus phosphovorus) and two glycogen accumulating organisms (GAOs) (i.e., Candidatus Competibacter phosphatis and Micropruina glycogenica). The results show that glucose might not select for Candidatus Accumulibacter phosphatis. However, Microlunatus phosphovorus, Candidatus Competibacter phosphatis, and Micropruina glycogenica might be selected. The highest percent relative abundance (% RA) of Candidatus Accumulibacter phosphatis was about 42%; this occurred at the beginning of the experimental period when phosphorus removal was efficient. However, the % RA of these bacteria decreased, reaching below 4% at the end of the run. The maximum % RA of Microlunatus phosphovorus, Candidatus Competibacter phosphatis, and Micropruina glycogenica was about 21, 37, 17%, respectively. It appears that a higher glucose concentration might be detrimental for Microlunatus phosphovorus and Micropruina glycogenica. Results also indicate a dominance of GAOs over PAOs when EBPR systems are fed with glucose. It is possible that the GAOs outcompete the PAOs at low pH values; it has been reported that at low pH, GAOs use glycogen as the energy source to uptake glucose. As a result, P-removal deteriorated. Therefore, glucose is not a strong candidate as a carbon source to supplement EBPR systems that do not contain sufficient volatile fatty acids.

  9. Phosphorus balance and mineral metabolism with 3 h daily hemodialysis.

    PubMed

    Ayus, J C; Achinger, S G; Mizani, M R; Chertow, G M; Furmaga, W; Lee, S; Rodriguez, F

    2007-02-01

    Poor control of mineral metabolism is independently associated with mortality in patients receiving hemodialysis. We analyzed data from a 12-month, prospective, non-randomized, controlled study of daily hemodialysis (DHD) (six sessions/week 3 h each) (n=26) vs conventional hemodialysis (CHD) (three sessions/week 4 h each) (n=51) for achievement of mineral metabolism goals and we performed a substudy of weekly dialytic phosphorus removal in DHD vs CHD. Phosphorus control was superior in the DHD group (% change from baseline to end-of-study -27+/-30% vs +7%+/-35% in the CHD group, P=0.0001). Percentage of patients using phosphate binders decreased from 77 to 40% among subjects on DHD, whereas these parameters did not change (76 vs 77%) in the CHD group (P=0.03 by Breslow-Day test for homogeneity of the odds ratios). Weekly mean phosphorus removal was higher in the DHD group (2452+/-720 mg/week vs 1572+/-366 mg/week, P=0.04). Mean normalized protein catabolic rate increased (0.90+/-0.43-1.22+/-0.26 g/kg/day, P=0.0013). DHD was also associated with an increase in the percent of subjects achieving three or more mineral metabolism goals (for phosphorus, calcium x phosphorus and parathyroid hormone) (15 vs 46%, P=0.046). In conclusion, DHD improves phosphorus control by increasing dialytic phosphorus removal while maintaining nutritional status and reducing the use of phosphate binders. The net effect allows for improved achievement of mineral metabolism goals. PMID:17191084

  10. Changes in phosphorus smoke chemistry with environmental conditions

    SciTech Connect

    McFadden, K.M.; Ligotke, M.W.; Garland, T.R.; Van Voris, P.; Schirmer, R.E.

    1985-09-01

    Physical and chemical characteristics of two phosphorus aerosols were measured under a limited number of environmental conditions. The exposures and measurements were performed in a wind tunnel under various humidities, wind speeds and, to a limited extent, aerosol ages. Temperature, another important environmental variable that may influence the chemical form of the aerosols, was not studied in this research program. Steady-state aerosols generated by combustion of red phosphorus/butyl rubber (RP/BR) and white phosphorus (WP) were suspended in a closed-loop wind tunnel to simulate the continuous-generation of these obscurants at Army field training sites. Measured aerosol characteristics were found to differ significantly from characteristics predicted by simple phosphoric acid models previously thought to represent the chemical form of the suspended particles. As many as 28 individual phosphorus species were detected in aerosol samples. The distribution of linear and cyclic phosphorus species in the sampled aerosol was observed to vary significantly for changes in both aerosol age (0 to 60 min) and relative humidity (<5% to 90%). Hydrolysis toward phosphate occurred as the aerosol aged, and the rate of change was slower for higher humidities. More high-order phosphorus species appeared to be formed during aerosol generation at low relative humidities than at high humidity, as revealed by measurements near the combustion zone. Steady-state aerosols showed decreasing conversion to phosphate with increasing humidity. The highly speciated aerosols hydrolyzed to phosphate in less than 18 hr after deposition onto dry surfaces. Other aerosol characteristics such as mass concentration, water and phosphorus content of the particles, and particle size distribution were also measured.

  11. Phosphorus forms and controls on phosphorus dynamics in sediments from Monterey Bay, California

    NASA Astrophysics Data System (ADS)

    Cade-Menun, B. J.; Paytan, A.

    2007-12-01

    Phosphorus is an essential element for all organisms. Phosphorus can be removed from the water column as sinking particulate matter, where it may either be buried or remineralized and released to the water column. The objective of our study was to determine P forms, dynamics and variability in sediment samples from Monterey Bay, CA. Six pushcore samples were randomly collected from a 2-m2 area, and were divided into 4 layers, each 1.5-2.5 cm thick. Samples were analyzed for total P, C and N, P forms by 31P NMR spectroscopy and SEDEX fractionation, phosphatase activity, and P retention. Total P, C and N did not change with depth, but there were significant changes with depth for P forms by NMR and SEDEX, and well as alkaline phosphatase and diesterase activity. However, P retention was strong in all layers and increased with depth, suggesting that remineralized P not taken up by organisms is sorbed onto sediment minerals rather than released to the surface water.

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

    PubMed

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

    2011-03-01

    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.

  13. Phosphorus depletion in forest soils shapes bacterial communities towards phosphorus recycling systems.

    PubMed

    Bergkemper, Fabian; Schöler, Anne; Engel, Marion; Lang, Friederike; Krüger, Jaane; Schloter, Michael; Schulz, Stefanie

    2016-06-01

    Phosphorus (P) is an important macronutrient for all biota on earth but similarly a finite resource. Microorganisms play on both sides of the fence as they effectively mineralize organic and solubilize precipitated forms of soil phosphorus but conversely also take up and immobilize P. Therefore, we analysed the role of microbes in two beech forest soils with high and low P content by direct sequencing of metagenomic deoxyribonucleic acid. For inorganic P solubilization, a significantly higher microbial potential was detected in the P-rich soil. This trait especially referred to Candidatus Solibacter usiatus, likewise one of the dominating species in the data sets. A higher microbial potential for efficient phosphate uptake systems (pstSCAB) was detected in the P-depleted soil. Genes involved in P starvation response regulation (phoB, phoR) were prevalent in both soils. This underlines the importance of effective phosphate (Pho) regulon control for microorganisms to use alternative P sources during phosphate limitation. Predicted genes were primarily harboured by Rhizobiales, Actinomycetales and Acidobacteriales. PMID:26690731

  14. 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.

  15. 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.

  16. Optimizing phosphorus diffusion for photovoltaic applications: Peak doping, inactive phosphorus, gettering, and contact formation

    NASA Astrophysics Data System (ADS)

    Wagner, Hannes; Dastgheib-Shirazi, Amir; Min, Byungsul; Morishige, Ashley E.; Steyer, Michael; Hahn, Giso; del Cañizo, Carlos; Buonassisi, Tonio; Altermatt, Pietro P.

    2016-05-01

    The phosphosilicate glass (PSG), fabricated by tube furnace diffusion using a POCl3 source, is widely used as a dopant source in the manufacturing of crystalline silicon solar cells. Although it has been a widely addressed research topic for a long time, there is still lack of a comprehensive understanding of aspects such as the growth, the chemical composition, possible phosphorus depletion, the resulting in-diffused phosphorus profiles, the gettering behavior in silicon, and finally the metal-contact formation. This paper addresses these different aspects simultaneously to further optimize process conditions for photovoltaic applications. To do so, a wide range of experimental data is used and combined with device and process simulations, leading to a more comprehensive interpretation. The results show that slight changes in the PSG process conditions can produce high-quality emitters. It is predicted that PSG processes at 860 °C for 60 min in combination with an etch-back and laser doping from PSG layer results in high-quality emitters with a peak dopant density Npeak = 8.0 × 1018 cm-3 and a junction depth dj = 0.4 μm, resulting in a sheet resistivity ρsh = 380 Ω/sq and a saturation current-density J0 below 10 fA/cm2. With these properties, the POCl3 process can compete with ion implantation or doped oxide approaches.

  17. 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

  18. Conditional phosphorus index as an educational tool for risk assessment and phosphorus management.

    PubMed

    Djodjic, Faruk; Bergström, Lars

    2005-06-01

    Phosphorus index (PI) is a risk-assessment tool that combines phosphorus (P) source factors and transport factors to rank the vulnerability of fields to P losses. Here we present the structure and concepts of conditional PI, developed as an educational and P-management tool adjusted for Swedish conditions. Because the significance of certain factors for P losses depends on their interplay with other factors, conditional rules are needed for a more accurate process description and quantification. Accounting for P losses through the soil profile, separate calculations for reactive and unreactive P and a changed approach to P loss assessment from erosion losses are some of the new features included in the tool presented here. The performance of the tool was tested by comparing the calculated PI values with measured annual P transport from seven observation fields included in a Swedish water quality monitoring program. This first test indicated that the tool could be used successfully for P loss risk assessment. PMID:16092259

  19. [Phosphorus forms of the suspended particulate matter in the Yellow River downstream during water and sediment regulation 2008].

    PubMed

    Wei, Jun-Feng; Chen, Hong-Tao; Liu, Yue-Liang; Shan, Kai; Yao, Qing-Zhen; He, Hui-Jun; Yu, Zhi-Gang

    2011-02-01

    Suspended particulate matter samples were collected from Lijin Station on the Yellow River during the 2008 water and sediment regulation. Using water elutriation method, samples were physically separated according to grain size, and phosphorus forms were detected by the improved SEDEX technology. Results show that authigenic apatite phosphorus and organic phosphorus are the dominant forms of the particulate phosphorus. During water and sediment regulation, concentrations of total particulate phosphorus, loosely adsorbed phosphorus, organic phosphorus and refractory phosphorus are lower than those in other time of the year, while the concentration of detrital fluorapatite phosphorus is higher than that in other time. Grain size is the primary variable in the determination of the content of various particulate phosphorus forms. In fine particles, loosely adsorbed phosphorus, organic phosphorus and refractory phosphorus concentrations are high, while detrital fluorapatite phosphorus concentration is high in coarse particles. About 28.3% of the total particulate phosphorus is in the form of bio-available phosphorus, of which organic phosphorus is the major component. During the water and sediment regulation, the fluxes of sediment, particulate phosphorus and particulate bio-available phosphorus are 6.63 x 10(7) t, 3.42 x 10(4) t, and 8.30 x 10(3) t, which are 83.2%, 78.6%, and 80.2% each of the total fluxes in 2008.

  20. Removal of nitrogen and phosphorus from the secondary effluent in tertiary denitrifying biofilters combined with micro-coagulation.

    PubMed

    Wei, Nan; Shi, Yunhong; Wu, Guangxue; Hu, Hongying; Guo, Yumei; Wu, Yihui; Wen, Hui

    2016-01-01

    Effective control of nitrogen and phosphorus in secondary effluent can reduce or avoid the eutrophication of receiving water bodies. Two denitrifying biofilters (DNBFs) packed with different sizes of quartz sands combined with micro-coagulation were operated for simultaneous removal of nitrogen and phosphorus from the secondary effluent. The quartz sand size in one DNBF was 2-4 mm (DNBFS), and in the other was 4-6 mm (DNBFL). In both DNBFs, methanol was used as the electron donor and different organic carbon to nitrogen (C/N) ratios were applied. Under C/N ratios of 1.5, 1.25, and 0.75 g/g, the nitrate nitrogen (NO3(-)-N) removal percentages were 73%, 77%, and 50% in DNBFS, and 43%, 25%, and 21% in DNBFL; the effluent total phosphorus concentrations were 0.15, 0.14, and 0.18 mg/L in DNBFS, and 0.29, 0.35, and 0.24 mg/L in DNBFL. The performance of both biofilters was quite stable within a backwashing cycle. The NO3(-)-N reduction rates were 1.31, 1.10, and 0.48 mg/(L·min) in DNBFS, and 0.97, 0.27, and 0.10 mg/(L·min) in DNBFL. For biomass detached from both biofilters, their denitrifying activities were similar. Biofilm biomass in DNBFS was higher than that in DNBFL, inducing a high denitrification efficiency in DNBFS.

  1. Removal of nitrogen and phosphorus from the secondary effluent in tertiary denitrifying biofilters combined with micro-coagulation.

    PubMed

    Wei, Nan; Shi, Yunhong; Wu, Guangxue; Hu, Hongying; Guo, Yumei; Wu, Yihui; Wen, Hui

    2016-01-01

    Effective control of nitrogen and phosphorus in secondary effluent can reduce or avoid the eutrophication of receiving water bodies. Two denitrifying biofilters (DNBFs) packed with different sizes of quartz sands combined with micro-coagulation were operated for simultaneous removal of nitrogen and phosphorus from the secondary effluent. The quartz sand size in one DNBF was 2-4 mm (DNBFS), and in the other was 4-6 mm (DNBFL). In both DNBFs, methanol was used as the electron donor and different organic carbon to nitrogen (C/N) ratios were applied. Under C/N ratios of 1.5, 1.25, and 0.75 g/g, the nitrate nitrogen (NO3(-)-N) removal percentages were 73%, 77%, and 50% in DNBFS, and 43%, 25%, and 21% in DNBFL; the effluent total phosphorus concentrations were 0.15, 0.14, and 0.18 mg/L in DNBFS, and 0.29, 0.35, and 0.24 mg/L in DNBFL. The performance of both biofilters was quite stable within a backwashing cycle. The NO3(-)-N reduction rates were 1.31, 1.10, and 0.48 mg/(L·min) in DNBFS, and 0.97, 0.27, and 0.10 mg/(L·min) in DNBFL. For biomass detached from both biofilters, their denitrifying activities were similar. Biofilm biomass in DNBFS was higher than that in DNBFL, inducing a high denitrification efficiency in DNBFS. PMID:27232413

  2. Pyromineralization of soil phosphorus in savanna ecosystems

    NASA Astrophysics Data System (ADS)

    Hartshorn, A.; Coetsee, C.; Chadwick, O.

    2007-12-01

    The weathering of rock supplies phosphorus (P) to ecosystems. Phosphorus limitation of ecosystems can be severe in thicker or older soils, where soil production rates from rock and therefore release of P is slower than in thinner or younger soils. Limitation may be especially pronounced in drier ecosystems that are experiencing increasing N deposition. Our savanna field sites in Kruger National Park, South Africa meet all three of these criteria: soil residence times average 250 ky, the climate is semiarid, and N inputs average 20 kg ha-1 y-1. Not all soil P is plant-available, and because our field sites experience occasional fires, our objectives were to quantify the importance of pyromineralization of soil P, the transfer by fire of soil P from recalcitrant to labile (HCO3- extractable) pools. We quantified these soil P pools using a modified Hedley scheme (an array of chemical extractants). Three sets of soils were fractionated: 1. soils from 10 profiles along an intensively studied hillslope, bracketing a pronounced structural and functional ecotone; 2. surface soils from these 10 profiles after a simulated burn; and 3. surface soils from the Shabeni Experimental Plots, where 4 fire treatments have been maintained for decades: no fire, annual fire in the dry season, triennial fire in the dry season, and triennial fire in the wet season. Total P for hillslope soils ranged from 45 to 135 g m-2 (to 50 cm depth) and from 8 to 15 g m-2 (to 5 cm depth). Total soil P was lowest in midslope soils, where upslope sandy soils dominated by broad-leafed vegetation shift abruptly to downslope clayey soils with fine-leafed vegetation. Simulated fire for the hillslope soils reduced total P slightly, but boosted labile P by 1.7 g m-2 (to 5 cm), representing 17% of total P in the surface 5 cm. This pyromineralization effect was not uniform across the hillslope: downslope soils gained about 50% more labile P than midslope soils with simulated burning. With a fire return interval

  3. Extraction Methods in Soil Phosphorus Characterisation

    NASA Astrophysics Data System (ADS)

    Soinne, Helena

    2010-05-01

    Extraction methods are widely used to assess the bioavailability of P and to characterise soil P reserves. Even though new and more sophisticated methods to characterise soil P are constantly developed the use of extraction methods is not likely to be replaced because of the relatively simple analytical equipment needed for the analysis. However, the large variety of extractants, pre-treatments and sample preparation procedures complicate the comparison of published results. In order to improve our understanding of the behaviour and cycling of P in soil, it is important to know the role of extracted P in the soil P cycle. The knowledge of the factors affecting the analytical outcome is a prerequisite for justified interpretation of the results. In this study, the effect of sample pre-treatment and properties of the used extractant on extractable molybdate-reactive phosphorus (MRP) and molybdate-unreactive phosphorus (MUP) was studied. Furthermore, the effect of sample preparation procedures prior the analysis on measured MRP and MUP was studied. Two widely used sequential extraction procedures were compared on their ability to show management induced differences on soil P. These results revealed that pre-treatments changed soil properties and air-drying was found to affect soil P, particularly extractable MUP, thought to represent organic P, by disrupting organic matter. This was evidenced by an increase in the water-extractable small-sized (<0.2 µm) P that, at least partly, took place at the expense of the large-sized (>0.2 µm) P. In addition to the effects of sample pre-treatment, the results showed that extractable organic P was sensitive to the chemical nature of the used extractant and to the sample preparation procedures employed prior to P analysis, including centrifugation and filtering of soil suspensions. Filtering may remove a major proportion of extractable MUP; therefore filtering cannot be recommended in the characterisation of solubilised MUP

  4. 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

  5. Phosphorus flux from wetland ditch sediments.

    PubMed

    Hill, C R; Robinson, J S

    2012-10-15

    The accumulation of phosphorus (P) in the bottom sediment of field drainage ditches poses a threat to the ecology both of the ditch water and downstream water courses. We investigated the amounts, forms and internal loading of sediment-bound P along two drainage ditches that regulate water levels in a basin fen (~200 ha) supporting a mixture of restored wetland and drained agricultural fields. Water levels in the Lady's Drove Rhyne are currently managed to enhance the biodiversity of the wetland (Catcott Lows Reserve - an area formerly cultivated for arable crop production); whereas, the East Ditch is managed to drain adjoining land that remains under arable and livestock production. Laboratory-based chemical fractionation schemes were used to characterise the forms and potential mobility of the sediment-bound P, whilst pore-water equilibrators were employed in situ to evaluate the diffusive flux of P through the sediment-water column, and to characterise the corresponding redox conditions. Along both ditches, sediment pore-water profiles indicated conditions ranging from weakly to very reducing conditions with increasing depth, and net fluxes of P from the sediment to overlying water. P flux values ranged from 0.33 to 1.30 mg m(-2) day(-1). Both the degree of P saturation (DPS) of the sediment and NaOH extractable (Fe/Al-bound) P correlated significantly (P<0.05) with P flux. Both in the wetland and agricultural ditches, by far the highest values for P flux were recorded at sites closest to points of drainage water entry from the corresponding, adjoining land. Although the P flux data were obtained from only a single sampling event, this study highlights the contribution of historical as well as ongoing agricultural land use on the sustained elevated P status of ditch sediments in lowland catchments.

  6. The "phosphorus pyramid": a visual tool for dietary phosphate management in dialysis and CKD patients.

    PubMed

    D'Alessandro, Claudia; Piccoli, Giorgina B; Cupisti, Adamasco

    2015-01-20

    Phosphorus retention plays a pivotal role in the onset of mineral and bone disorders (MBD) in chronic kidney disease (CKD). Phosphorus retention commonly occurs as a result of net intestinal absorption exceeding renal excretion or dialysis removal. The dietary phosphorus load is crucial since the early stages of CKD, throughout the whole course of the disease, up to dialysis-dependent end-stage renal disease.Agreement exits regarding the need for dietary phosphate control, but it is quite challenging in the real-life setting. Effective strategies to control dietary phosphorus intake include restricting phosphorus-rich foods, preferring phosphorus sourced from plant origin, boiling as the preferred cooking procedure and avoiding foods with phosphorus-containing additives. Nutritional education is crucial in this regard.Based on the existing literature, we developed the "phosphorus pyramid", namely a novel, visual, user-friendly tool for the nutritional education of patients and health-care professionals. The pyramid consists of six levels in which foods are arranged on the basis of their phosphorus content, phosphorus to protein ratio and phosphorus bioavailability. Each has a colored edge (from green to red) that corresponds to recommended intake frequency, ranging from "unrestricted" to "avoid as much as possible".The aim of the phosphorus pyramid is to support dietary counseling in order to reduce the phosphorus load, a crucial aspect of integrated CKD-MBD management.

  7. Investigation of the phosphorus removal capacities of basic oxygen furnace slag under variable conditions.

    PubMed

    Han, Chong; Wang, Zhen; Yang, Wangjin; Wu, Qianqian; Yang, He; Xue, Xiangxin

    2016-01-01

    Effects of reaction time, initial phosphorus concentration, basic oxygen furnace slag (BOF-slag) dosage and size, and temperature on the phosphorus removal capacities (PRCs) of BOF-slag have been investigated in detail through batch tests. Weakly bound phosphorus, Fe- and Al-associated phosphorus, and Ca-associated phosphorus from fresh and reacted BOF-slag were analysed using sequential chemical extraction processes. It was determined that the PRCs of BOF-slag increased with the increase of initial phosphorus concentration and temperature while it decreased with the increase of BOF-slag dosage and size. The phosphorus removed by BOF-slag was primarily assigned to weakly bound phosphorus and Ca-associated phosphorus. Weakly bound phosphorus showed a significant decrease with the increase in all experimental parameter values. However, Ca-associated phosphorus exhibited a prominent increase with increasing reaction time, initial phosphorus concentration, and temperature. These demonstrate that experimental parameters can simultaneously affect the PRCs of BOF-slag and the ways of phosphorus removal by BOF-slag.

  8. Factors controlling phosphorus speciation in a Mediterranean basin (River Guadalfeo, Spain)

    NASA Astrophysics Data System (ADS)

    Avilés, Antonio; Rodero, Jesús; Amores, Victoria; de Vicente, Inmaculada; Rodríguez, M. Isabel; Niell, F. Xavier

    2006-12-01

    SummaryThere is a lot of interest nowadays in the role of riverbed sediments in phosphorus cycling and particularly, in the processes that lead the exchange of phosphorus between the sediment and the water column. This study presents results on phosphorus forms and other properties from surface riverbed sediments of the River Guadalfeo and its main tributaries. Results show a wide range of spatial variability within the basin with differences of phosphorus concentration higher than an order of magnitude among different sites. The most abundant form is the apatite inorganic phosphorus (AIP) which accounts for 68% of total phosphorus followed by total organic phosphorus (OP) that represents 29%. The high oversaturation of calcite reached during the summer and early autumn in most studied rivers shows as calcite-phosphorus co-precipitation is the most important self-cleansing mechanism that removes phosphorus from the water column, controlling the phosphorus content in the sediment and the dominance of AIP. Hydroxyapatite formation is only important in a few sampling points, in spite of the vastly oversaturation obtained. External factors such as the lithology of drainage area and sewage inputs are less important in the concentration of sediment phosphorus than physico-chemical and biological processes that take place in the rivers. Taking into account the low biodegradable characteristics of dominant phosphorus forms, it could be concluded that the surface sediment in the Guadalfeo basin acts as a phosphorus sink.

  9. Influence of Phosphorus Cycle Coupling on Carbon-Climate Feedbacks

    NASA Astrophysics Data System (ADS)

    Yang, X.; Thornton, P. E.; Ricciuto, D. M.; Hoffman, F. M.

    2014-12-01

    It is being increasingly recognized that carbon-nutrient interactions play important roles in regulating terrestrial carbon cycle responses to increasing CO2 in the atmosphere and climate change. Nitrogen-enabled models in CMIP5 indicated that the inclusion of nitrogen cycle reduces CO2 fertilization effect and warming-induced carbon loss from land ecosystems. None of the CMIP5 models has considered phosphorus (P) as a limiting nutrient. Phosphorus has been commonly considered to be the most limiting nutrient in lowland tropical forests. Only recently a few land models have considered P dynamics and C-N-P interactions (CASA-CNP, JSBACH-CNP and CLM-CNP) and these models show strong P limitation in tropical forest responses to increasing atmospheric CO2. In this study, we have performed a set of offline global-scale simulations using CLM-CNP constrained by realistic maps of phosphorus distribution. We examine the influence of including phosphorus cycle dynamics and C-N-P interactions on C-climate feedbacks. We illustrate the spatial patterns of dominant nutrient limitation (N-limited vs. P-limited) on the global scale. We show that P-limitation dominates over most of the tropics and sub-tropics, while N limitation dominates over most of the temperate and high-latitude regions. We also show that phosphorus cycle coupling reduces the sensitivity of net carbon exchange to variations in both temperature and precipitation.

  10. Isotopic Fingerprint for Phosphorus in Drinking Water Supplies.

    PubMed

    Gooddy, Daren C; Lapworth, Dan J; Ascott, Matthew J; Bennett, Sarah A; Heaton, Timothy H E; Surridge, Ben W J

    2015-08-01

    Phosphate dosing of drinking water supplies, coupled with leakage from distribution networks, represents a significant input of phosphorus to the environment. The oxygen isotope composition of phosphate (δ(18)OPO4), a novel stable isotope tracer for phosphorus, offers new opportunities to understand the importance of phosphorus derived from sources such as drinking water. We report the first assessment of δ(18)OPO4 within drinking water supplies. A total of 40 samples from phosphate-dosed distribution networks were analyzed from across England and Wales. In addition, samples of the source orthophosphoric acid used for dosing were also analyzed. Two distinct isotopic signatures for drinking water were identified (average = +13.2 or +19.7‰), primarily determined by δ(18)OPO4 of the source acid (average = +12.4 or +19.7‰). Dependent upon the source acid used, drinking water δ(18)OPO4 appears isotopically distinct from a number of other phosphorus sources. Isotopic offsets from the source acid ranging from -0.9 to +2.8‰ were observed. There was little evidence that equilibrium isotope fractionation dominated within the networks, with offsets from temperature-dependent equilibrium ranging from -4.8 to +4.2‰. While partial equilibrium fractionation may have occurred, kinetic effects associated with microbial uptake of phosphorus or abiotic sorption and dissolution reactions may also contribute to δ(18)OPO4 within drinking water supplies.

  11. 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.

  12. Impurity-to-band activation energy in phosphorus doped diamond

    NASA Astrophysics Data System (ADS)

    Stenger, I.; Pinault-Thaury, M.-A.; Kociniewski, T.; Lusson, A.; Chikoidze, E.; Jomard, F.; Dumont, Y.; Chevallier, J.; Barjon, J.

    2013-08-01

    The value of the impurity-to-band activation energy EA of a dopant is a basic feature of the electrical conductivity of semiconductors. Various techniques were used to determine EA in n-type diamond doped with phosphorus, giving values of EA varying from 0.43 eV to 0.63 eV, the value EA of 0.6 eV being commonly accepted for the ionization energy of phosphorus donors in diamond. Nevertheless, up to now, the dispersion of the experimental values of EA remains unexplained. In this work, we investigate the electrical properties of a set of n-type diamond homoepitaxial films with different phosphorus concentrations by Hall effect measurements in order to deduce EA and to understand the evolution of this energy with the dopant concentration. We show that, below 2 × 1019 cm-3 phosphorus, the decrease of EA is mainly controlled by the concentration of ionized defects resulting from the donor compensation. The role of ionized defects in the decrease of EA is analyzed on the basis of existing models adapted to the case of diamond. The proposed model provides a correct description of the experimental data. It can be used to quantitatively predict the activation energy of phosphorus in n-type diamond for given donor and compensating acceptor concentrations.

  13. Electron Doping of Ultrathin Black Phosphorus with Cu Adatoms.

    PubMed

    Koenig, Steven P; Doganov, Rostislav A; Seixas, Leandro; Carvalho, Alexandra; Tan, Jun You; Watanabe, Kenji; Taniguchi, Takashi; Yakovlev, Nikolai; Castro Neto, Antonio H; Özyilmaz, Barbaros

    2016-04-13

    Few-layer black phosphorus is a monatomic two-dimensional crystal with a direct band gap that has high carrier mobility for both holes and electrons. Similarly to other layered atomic crystals, like graphene or layered transition metal dichalcogenides, the transport behavior of few-layer black phosphorus is sensitive to surface impurities, adsorbates, and adatoms. Here we study the effect of Cu adatoms onto few-layer black phosphorus by characterizing few-layer black phosphorus field effect devices and by performing first-principles calculations. We find that the addition of Cu adatoms can be used to controllably n-dope few layer black phosphorus, thereby lowering the threshold voltage for n-type conduction without degrading the transport properties. We demonstrate a scalable 2D material-based complementary inverter which utilizes a boron nitride gate dielectric, a graphite gate, and a single bP crystal for both the p- and n-channels. The inverter operates at matched input and output voltages, exhibits a gain of 46, and does not require different contact metals or local electrostatic gating. PMID:26938106

  14. Phosphorus Recovery Using Zirconium-Loaded Saponified Orange Juice Residue

    NASA Astrophysics Data System (ADS)

    Harada, Hiroyuki; Kondo, Mitsunori; Biswas, Biplob K.; Ohura, Seichirou; Inoue, Katsutoshi; Ishikawa, Susumu; Kawakita, Hidetaka; Ohto, Keisuke

    Zirconium was immobilized to orange juice residue, to investigate the feasibility of using zirconium-loaded saponified orange juice residue (Zr-SOJR) for phosphorus recovery from secondary effluent and the extraction solution from incinerated sewage sludge ash by using H2SO4 and HCl. These had phosphorus concentrations of 68.2 mg/dm3 and 5.9 mg/dm3, respectively. The phosphorus removal rate secondary effluent increased with an increasing solid/liquid ratio in batch experiments. The adsorption capacity of Zr-SOJR was also compared with those obtained using a synthetic phosphorus solution and using zirconium-loaded ferrite. The prepared absorbent was effective for phosphorus removal and exhibited a reasonably high sorption capacity, twice that of zirconium ferrite. Secondary effluent was treated by packed column, and this reached break-through after 300 bed volumes. The results from phosphorous extraction from the ash indicate that can be treated with acid to efficiently recover phosphorous and thus can be absorbed by Zr-SOJR.

  15. Electron Doping of Ultrathin Black Phosphorus with Cu Adatoms.

    PubMed

    Koenig, Steven P; Doganov, Rostislav A; Seixas, Leandro; Carvalho, Alexandra; Tan, Jun You; Watanabe, Kenji; Taniguchi, Takashi; Yakovlev, Nikolai; Castro Neto, Antonio H; Özyilmaz, Barbaros

    2016-04-13

    Few-layer black phosphorus is a monatomic two-dimensional crystal with a direct band gap that has high carrier mobility for both holes and electrons. Similarly to other layered atomic crystals, like graphene or layered transition metal dichalcogenides, the transport behavior of few-layer black phosphorus is sensitive to surface impurities, adsorbates, and adatoms. Here we study the effect of Cu adatoms onto few-layer black phosphorus by characterizing few-layer black phosphorus field effect devices and by performing first-principles calculations. We find that the addition of Cu adatoms can be used to controllably n-dope few layer black phosphorus, thereby lowering the threshold voltage for n-type conduction without degrading the transport properties. We demonstrate a scalable 2D material-based complementary inverter which utilizes a boron nitride gate dielectric, a graphite gate, and a single bP crystal for both the p- and n-channels. The inverter operates at matched input and output voltages, exhibits a gain of 46, and does not require different contact metals or local electrostatic gating.

  16. 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.

  17. 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

  18. Atomic and electronic structure of exfoliated black phosphorus

    SciTech Connect

    Wu, Ryan J.; Topsakal, Mehmet; Jeong, Jong Seok; Wentzcovitch, Renata M.; Mkhoyan, K. Andre; Low, Tony; Robbins, Matthew C.; Haratipour, Nazila; Koester, Steven J.

    2015-11-15

    Black phosphorus, a layered two-dimensional crystal with tunable electronic properties and high hole mobility, is quickly emerging as a promising candidate for future electronic and photonic devices. Although theoretical studies using ab initio calculations have tried to predict its atomic and electronic structure, uncertainty in its fundamental properties due to a lack of clear experimental evidence continues to stymie our full understanding and application of this novel material. In this work, aberration-corrected scanning transmission electron microscopy and ab initio calculations are used to study the crystal structure of few-layer black phosphorus. Directly interpretable annular dark-field images provide a three-dimensional atomic-resolution view of this layered material in which its stacking order and all three lattice parameters can be unambiguously identified. In addition, electron energy-loss spectroscopy (EELS) is used to measure the conduction band density of states of black phosphorus, which agrees well with the results of density functional theory calculations performed for the experimentally determined crystal. Furthermore, experimental EELS measurements of interband transitions and surface plasmon excitations are also consistent with simulated results. Finally, the effects of oxidation on both the atomic and electronic structure of black phosphorus are analyzed to explain observed device degradation. The transformation of black phosphorus into amorphous PO{sub 3} or H{sub 3}PO{sub 3} during oxidation may ultimately be responsible for the degradation of devices exposed to atmosphere over time.

  19. Analyses of phosphorus in sewage by fraction method.

    PubMed

    Choi, Hee-Jeong; Choi, Chul-Ho; Lee, Seung-Mok

    2009-08-15

    Several forms of the phosphorus in wastewater were analyzed using a fraction method with a membrane reactor. A primary aim of this study was to differentiate the two main groups, as either "biologically bound" or "physicochemically bound," with the quantification of bound phosphorus in animated sludge. After the four-level extraction treatment with distilled water and various solvents such as bicarbonate-dithionate, NaOH and HCl, the redox-sensitive-P and P bound to Fe(III)-hydroxides were found as main precipitation products in the anaerobic chamber (AN). Whereas the aerobic chamber (AE) contained mainly the precipitates of P bound to metals, such as Al and Fe, sorptive-bound phosphorus on metals and organic compounds etc. With iron precipitation, the levels of Fe-P, Al-P, and Fe-P adsorbed by Fe(OH)(3) were particularly high in the AE and AN. The sum of inorganic-P (physicochemically bound phosphorus) increased with iron precipitation, whereas that of organic-P and poly P (biologically bound phosphorus) decreased. PMID:19188022

  20. Oceanic phosphorus imbalance: Magnitude of the mid-ocean ridge flank hydrothermal sink

    NASA Astrophysics Data System (ADS)

    Wheat, C. Geoffrey; McManus, James; Mottl, Michael J.; Giambalvo, Emily

    2003-09-01

    We present a new estimate for the crustal phosphorous sink that results from reactions among seawater, basalt, and sediment blanketing low temperature mid-ocean ridge flank hydrothermal systems. New estimates for global hydrothermal power output, sediment thickness, and the dissolved phosphate concentrations in basement formation fluids indicate that fluid flow through ridge flanks removes 2.8 × 1010 mol P yr-1. This value is larger (130%) than the riverine dissolved flux of inorganic phosphate and is as much as 35% of the sedimentary P sink. The concordant seawater flux (2.1 × 1016 kg yr-1) is 65% of the riverine fluid flux and circulates a fluid volume equivalent to the entire ocean in about 70,000 yr. Additional sampling of seafloor springs is required to further constrain the range of calculated phosphate fluxes; nevertheless the modern phosphorus budget is clearly unbalanced with total sinks outpacing sources.

  1. Role of simulated acid rain on cations, phosphorus, and organic matter dynamics in Latosol.

    PubMed

    Ling, Da-Jiong; Zhang, Jia-En; Ouyang, Ying; Huang, Qian-chun

    2007-01-01

    Acid rain is a serious environmental problem in the world and is of a particular concern in southern China where most of the soils are acidic. This study investigated the dynamics of cations, phosphorus (P), and soil organic matter (SOM) in the Latosol (acidic red soil) from south China under the influences of simulated acid rain (SAR). Laboratory experiments were performed by leaching the soil columns with SAR at pH levels ranging from 2.5 to 7.0 over a 21-day experimental period. Results show that about 34, 46, 20, and 77% of the original exchangeable soil Ca(+2), Mg(+2), K(+), and Na(+), respectively, were leached out by the SAR at pH 2.5 after 21 days. Two distinct patterns of the available phosphorus (AP) concentrations were observed: one at pH< or =3.5 and the other at pH > or = 4.0. At pH< or =3.5, concentrations of the AP increased from the beginning of the experiments to day 5, then decreased from day 5 to 15, and finally increased from day 15 to the end of the experiments. At pH > or = 4.0, concentrations of the AP increased consecutively from the beginning of the experiments to day 10 and decreased from day 10 to the end of the experiments. Such a finding is useful for agricultural practices since soil P is one of the most important macronutrients for plant growth. In general, SOM content decreased with time as the Latosol was leached by the SAR at all pH levels. A maximum concentration of soil fulvic acid was found after 15 days of the experiments due to the degradation of the SOM. A multiple regression analysis showed that a very strong relationship was obtained between the soil AP and the other three parameters (i.e., pH, SOM, and sorption P).

  2. Impact of fish farming on the distribution of phosphorus in sediments in the middle Adriatic area.

    PubMed

    Matijević, Slavica; Kuspilić, Grozdan; Kljaković-Gaspić, Zorana; Bogner, Danijela

    2008-03-01

    During the last decade, intensive fish farming developed along the central Croatian coast, creating a need to study and evaluate its potential influence on unaffected sites. We considered phosphorus as an indicator of the influence of fish farming and investigated the distribution of phosphorus forms in sediment from several fish farms and marine areas of different trophic status in the middle Adriatic. Analyses of samples were performed with modified SEDEX techniques. Our results indicated that authigenic apatite phosphorus showed no significant differences among the investigated stations, while organic phosphorus concentrations reflected the trophic status of the station area. Below-cage sediment was characterized by enhanced fish debris phosphorus and low detrital apatite phosphorus concentrations, while sediment from an anthropogenically influenced bay showed the highest values of iron bound phosphorus species. Among the different P fractions, fish debris phosphorus proved to be the most sensitive indicator of the influence of fish farming on marine sediment.

  3. Dissolved phosphorus speciation of flash carbonization, slow pyrolysis, and fast pyrolysis biochars

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Pyrolysis of waste biomass is a promising technology to produce sterile and renewable organic phosphorus fertilizers. Systematic studies are necessary to understand how different pyrolysis platforms influence the chemical speciation of dissolved (bioavailable) phosphorus. This study employed solut...

  4. Quantitative changes of calcium, phosphorus, and magnesium in common iliac arteries with aging.

    PubMed

    Tohno, S; Tohno, Y; Moriwake, Y; Azuma, C; Ohnishi, Y; Minami, T

    2001-01-01

    To elucidate the mechanism of element accumulations in the arteries with aging, the authors investigated the mass ratios among calcium, phosphorus, and magnesium in the common iliac arteries by inductively coupled plasma-atomic emission spectrometry. The subjects consisted of 16 men and 8 women, ranging in age from 65 to 93 yr. It was found that there were extremely significant correlations between calcium and phosphorus contents, between calcium and magnesium contents, and between phosphorus and magnesium contents in the common iliac arteries. In regard to the mass ratio, although the mass ratio of calcium to phosphorus was almost constant, the mass ratios of magnesium to calcium and phosphorus were different at early and advanced stages of the accumulation of calcium and phosphorus. It was found that both the mass ratios of magnesium to calcium and phosphorus were higher at an early stage of the accumulation of calcium and phosphorus in the arteries than at an advanced stage of the accumulation.

  5. HANDBOOK: RETROFITTING POTWS FOR PHOSPHORUS REMOVAL IN THE CHESAPEAKE BAY DRAINAGE BASIN

    EPA Science Inventory

    This document assesses the technology, economics, and efficiency of phosphorus removal processes for use in the Chesapeake Bay Drainage basin (CBDB). ince phosphorus removal requirements in the CBDB vary widely with geographic location, this document discusses the feasibility of ...

  6. Microbial and metabolic characterization of a denitrifying phosphorus-uptake/side stream phosphorus removal system for treating domestic sewage.

    PubMed

    Jin, Zhan; Ji, Fang-Ying; Xu, Xuan; Xu, Xiao-Yi; Chen, Qing-Kong; Li, Qi

    2014-11-01

    In this study, an advanced wastewater treatment process, the denitrifying phosphorus/side stream phosphorus removal system (DPR-Phostrip), was developed for the purpose of enhancing denitrifying phosphorus removal. The enrichment of denitrifying phosphorus-accumulating organisms (DPAOs) and the microbial community structure of DPR-Phostrip were evaluated by polymerase chain reaction-denaturing gradient gel electrophoresis (PCR-DGGE), and the metabolic activity of seed sludge and activated sludge collected after 55 days of operation were evaluated by Biolog™ analysis. This experimental study of DPR-Phostrip operation showed that nutrients were removed effectively, and denitrifying phosphorus removal was observed during the pre-anoxic period. PCR-DGGE analysis indicated that DPR-Phostrip supported DPAO growth while inhibiting PAOs and GAOs. The major dominant species in DPR-Phostrip were Bacteroidetes bacterium, Saprospiraceae bacterium, and Chloroflexi bacterium. Moreover, the functional diversity indices calculated on the basis of Biolog analysis indicated that DPR-Phostrip had almost no effect on microbial community diversity but was associated with a shift in the dominant species, which confirms the results of the PCR-DGGE analysis. The results for average well color development, calculated via Biolog analysis, showed that DPR-Phostrip had a little impact on the metabolic activity of sludge. Further principal component analysis suggested that the ability to utilize low-molecular-weight organic compounds was reduced in DPR-Phostrip.

  7. Enhanced phosphorus nutrition in monocots and dicots over-expressing a phosphorus-responsive type I H+-pyrophosphatase.

    PubMed

    Yang, Haibing; Knapp, Jane; Koirala, Pratistha; Rajagopal, Divya; Peer, Wendy Ann; Silbart, Lawrence K; Murphy, Angus; Gaxiola, Roberto A

    2007-11-01

    Plants challenged by limited phosphorus undergo dramatic morphological and architectural changes in their root systems in order to increase their absorptive surface area. In this paper, it is shown that phosphorus deficiency results in increased expression of the type I H+-pyrophosphatase AVP1 (AVP, Arabidopsis vacuolar pyrophosphatase), subsequent increased P-type adenosine triphosphatase (P-ATPase)-mediated rhizosphere acidification and root proliferation. Molecular genetic manipulation of AVP1 expression in Arabidopsis, tomato and rice results in plants that outperform controls when challenged with limited phosphorus. However, AVP1 over-expression and the resulting rhizosphere acidification do not result in increased sensitivity to AlPO4, apparently because of the enhancement of potassium uptake and the release of organic acids. Thus, the over-expression of type I H+-pyrophosphatases appears to be a generally applicable technology to help alleviate agricultural losses in low-phosphorus tropical/subtropical soils and to reduce phosphorus runoff pollution of aquatic and marine environments resulting from fertilizer application. PMID:17711412

  8. Microbial and metabolic characterization of a denitrifying phosphorus-uptake/side stream phosphorus removal system for treating domestic sewage.

    PubMed

    Jin, Zhan; Ji, Fang-Ying; Xu, Xuan; Xu, Xiao-Yi; Chen, Qing-Kong; Li, Qi

    2014-11-01

    In this study, an advanced wastewater treatment process, the denitrifying phosphorus/side stream phosphorus removal system (DPR-Phostrip), was developed for the purpose of enhancing denitrifying phosphorus removal. The enrichment of denitrifying phosphorus-accumulating organisms (DPAOs) and the microbial community structure of DPR-Phostrip were evaluated by polymerase chain reaction-denaturing gradient gel electrophoresis (PCR-DGGE), and the metabolic activity of seed sludge and activated sludge collected after 55 days of operation were evaluated by Biolog™ analysis. This experimental study of DPR-Phostrip operation showed that nutrients were removed effectively, and denitrifying phosphorus removal was observed during the pre-anoxic period. PCR-DGGE analysis indicated that DPR-Phostrip supported DPAO growth while inhibiting PAOs and GAOs. The major dominant species in DPR-Phostrip were Bacteroidetes bacterium, Saprospiraceae bacterium, and Chloroflexi bacterium. Moreover, the functional diversity indices calculated on the basis of Biolog analysis indicated that DPR-Phostrip had almost no effect on microbial community diversity but was associated with a shift in the dominant species, which confirms the results of the PCR-DGGE analysis. The results for average well color development, calculated via Biolog analysis, showed that DPR-Phostrip had a little impact on the metabolic activity of sludge. Further principal component analysis suggested that the ability to utilize low-molecular-weight organic compounds was reduced in DPR-Phostrip. PMID:25073616

  9. Formulas for premature infants: fate of the calcium and phosphorus.

    PubMed

    Bhatia, J; Fomon, S J

    1983-07-01

    Formulas designed for feeding of premature infants contain minerals added by the manufacturer. Although it is known that these minerals may be poorly suspended in the formula, little is known about concentrations of minerals in formula delivered to the infant under conditions prevailing in premature infant nurseries. In partially empty bottles of Similac Special Care, concentrations of calcium and phosphorus of this residual formula were found to be substantially greater than concentrations in full bottles. Presumably, concentrations of calcium and phosphorus in formula delivered to the infants was relatively low. Enfamil Premature and SMA Preemie infant formulas contain lesser quantities of added calcium and demonstrated less tendency to sedimentation. Substantial decrease in concentration of calcium was observed with all three formulas during continuous infusion, but the decrease was greatest with Similac Special Care. Little or no change in concentrations of calcium and phosphorus were observed with simulated bolus feeding by gavage.

  10. 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.

  11. Plasmonic Properties of Silicon Nanocrystals Doped with Boron and Phosphorus.

    PubMed

    Kramer, Nicolaas J; Schramke, Katelyn S; Kortshagen, Uwe R

    2015-08-12

    Degenerately doped silicon nanocrystals are appealing plasmonic materials due to silicon's low cost and low toxicity. While surface plasmonic resonances of boron-doped and phosphorus-doped silicon nanocrystals were recently observed, there currently is poor understanding of the effect of surface conditions on their plasmonic behavior. Here, we demonstrate that phosphorus-doped silicon nanocrystals exhibit a plasmon resonance immediately after their synthesis but may lose their plasmonic response with oxidation. In contrast, boron-doped nanocrystals initially do not exhibit plasmonic response but become plasmonically active through postsynthesis oxidation or annealing. We interpret these results in terms of substitutional doping being the dominant doping mechanism for phosphorus-doped silicon nanocrystals, with oxidation-induced defects trapping free electrons. The behavior of boron-doped silicon nanocrystals is more consistent with a strong contribution of surface doping. Importantly, boron-doped silicon nanocrystals exhibit air-stable plasmonic behavior over periods of more than a year.

  12. Recovery of phosphates from elemental phosphorus bearing wastes

    SciTech Connect

    Edwards, R.E.; Moore, O.E.; Sullivan, J.M.

    1994-10-01

    A process for oxidizing aqueous elemental phosphorus containing residues (sludges) to produce orthophosphate containing slurries suitable for subsequent reaction with ammonia to produce nitrogen and phosphate containing fertilizer products is presented. It comprises reacting aqueous elemental phosphorus containing residues with certain special mixtures of concentrated nitric acid and sulfuric acid to effect the conversion of the elemental phosphorus into mostly orthophosphoric acid and very little orthophosphorus acid with the relative ratios of the two acids being dependent upon the mole ratio of H{sub 2}SO{sub 4}:HNO{sub 3} employed in the processing. The resulting aqueous reaction intermediate is neutralized with ammonia during processing to a fluid or solid fertilizer product. Prior to the conversion to products, the aqueous reaction intermediate may be subjected to a solids separation step to remove insoluble salts of certain environmentally undesirable metals, such as Pb, Cd, Ba, and Cr.

  13. 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

  14. Dynamics and Mechanisms of Exfoliated Black Phosphorus Sublimation.

    PubMed

    Fortin-Deschênes, Matthieu; Levesque, Pierre L; Martel, Richard; Moutanabbir, Oussama

    2016-05-01

    We report on real time observations of the sublimation of exfoliated black phosphorus layers throughout annealing using in situ low energy electron microscopy. We found that sublimation manifests itself above 375 ± 20 °C through the nucleation and expansion of asymmetric, faceted holes with the long axis aligned along the [100] direction and sharp tips defined by edges consisting of alternating (10) and (11) steps. This thermally activated process repeats itself via successive sublimation of individual layers. Calculations and simulations using density functional theory and kinetic Monte Carlo allowed to determine the involved atomic pathways. Sublimation is found to occur via detachments of phosphorus dimers rather than single atoms. This behavior and the role of defects is described using an analytical model that captures all essential features. This work establishes an atomistic-level understanding of the thermal stability of exfoliated black phosphorus and defines the temperature window available for material and device processing. PMID:27097073

  15. Phosphorus recovery from sewage sludge ash through an electrodialytic process.

    PubMed

    Guedes, Paula; Couto, Nazaré; Ottosen, Lisbeth M; Ribeiro, Alexandra B

    2014-05-01

    The electrodialytic separation process (ED) was applied to sewage sludge ash (SSA) aiming at phosphorus (P) recovery. As the SSA may have high heavy metals contents, their removal was also assessed. Two SSA were sampled, one immediately after incineration (SA) and the other from an open deposit (SB). Both samples were ED treated as stirred suspensions in sulphuric acid for 3, 7 and 14 days. After 14 days, phosphorus was mainly mobilized towards the anode end (approx. 60% in the SA and 70% in the SB), whereas heavy metals mainly electromigrated towards the cathode end. The anolyte presented a composition of 98% of P, mainly as orthophosphate, and 2% of heavy metals. The highest heavy metal removal was achieved for Cu (ca. 80%) and the lowest for Pb and Fe (between 4% and 6%). The ED showed to be a viable method for phosphorus recovery from SSA, as it promotes the separation of P from the heavy metals.

  16. Method for processing wastes resulting from production of phosphorus

    SciTech Connect

    Alzhanov, T.M.; Bykov, V.I.; Chernogorenko, V.B.; Dmitrenko, V.V.; Ishkhanov, E.S.; Kipchakbaev, A.D.; Koverya, V.M.; Lynchak, K.A.; Markovsky, E.A.; Muchnik, S.V.; Pobortsev, M.E.; Sapian, V.G.; Sergienko, V.Y.; Vopilov, A.N.

    1980-03-11

    The method comprises processing slime and off-gases resulting from the production of phosphorus with an aqueous solution of copper sulphate having a concentration of from 15 to 50% at a temperature within the range of from 20* to 80* C. As a result, two products are obtained, i.e., a liquid product and a solid one. The solid product containing mainly copper phosphide as well as fluorides and chlorides of alkali metals and silicon, and silicates of calcium and aluminum, is used as a modifying and refining agent for hypereutectic silumines and for the manufacture of a copper-phosphorus alloy. The liquid product containing phosphoric acid, sulphuric acid and copper sulphate is used as starting product for the preparation of a copper-containing fertilizer. The method according to the present invention makes it possible to modify the production of phosphorus so as to eliminate the formation of secondary wastes and improve the environmental control.

  17. 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.

  18. Weak localization in few-layer black phosphorus

    NASA Astrophysics Data System (ADS)

    Du, Yuchen; Neal, Adam T.; Zhou, Hong; Ye, Peide D.

    2016-06-01

    We have conducted a comprehensive investigation into the magneto-transport properties of few-layer black phosphorus in terms of phase coherence length, phase coherence time, and mobility via weak localization measurement and Hall-effect measurement. We present magnetoresistance data showing the weak localization effect in bare p-type few-layer black phosphorus and reveal its strong dependence on temperature and carrier concentration. The measured weak localization agrees well with the Hikami-Larkin-Nagaoka model and the extracted phase coherence length of 104 nm at 350 mK, decreasing as ˜T-0.513+-0.053 with increased temperature. Weak localization measurement allows us to qualitatively probe the temperature-dependent phase coherence time τ ϕ , which is in agreement with the theory of carrier interaction in the diffusive regime. We also observe the universal conductance fluctuation phenomenon in few-layer black phosphorus within moderate magnetic field and low temperature regime.

  19. Electronic band structure of surface-doped black phosphorus

    NASA Astrophysics Data System (ADS)

    Kim, Jimin; Ryu, Sae Hee; Sohn, Yeongsup; Kim, Keun Su

    2015-03-01

    There are rapidly growing interests in the study of few-layer black phosphorus owing to its promising device characteristics that may impact our future electronics technology. The low-energy band structure of black phosphorus has been widely predicted to be controllable by external perturbations, such as strain and doping. In this work, we attempt to control the electronic band structure of black phosphorous by in-situ surface deposition of alkali-metal atoms. We found that surface doping induces steep band bending towards the bulk, leading to the emergence of new 2D electronic states that are confined within only few phosphorene layers of black phosphorus. Using angle-resolved photoemission spectroscopy, we directly measured the electronic band structure and its evolution as a function of dopant density. Supported by IBS.

  20. Phosphorus: The Noose of Sustainability and Renewability in Steelmaking

    NASA Astrophysics Data System (ADS)

    Tayeb, Mohammed A.; Spooner, Stephen; Sridhar, Seetharaman

    2014-09-01

    With rising ore prices and the continued demand for higher quality steels, much work has been carried out into refining and control prospects of steel chemistry. As several technologies around the world are exploring the control of phosphorus with high priority, an overview of current knowledge, ongoing research, and specific interest areas is presented. The reliance of the basic oxygen furnace steelmaking on iron ore quality is considered with regard to impurity levels, as well as the phosphorus content of direct reduced iron introduction to the electric arc furnace process. This article reviews methods to control phosphorus in steelmaking and proposes a practical approach based on laboratory-scale equilibrium experiments. The article ends by exploring energy savings in steelmaking as well as speculating on further avenues of steel production profitability.

  1. Removal of Phosphorus in Metallurgical Silicon by Rare Earth Elements

    NASA Astrophysics Data System (ADS)

    Tang, Kai; Løvvik, Ole Martin; Safarian, Jafar; Ma, Xiang; Tangstad, Merete

    2014-09-01

    Removal of phosphorus in metallurgical silicon is one of the crucial steps for the production of solar grade Si feedstock. The possibility of doping rare earth elements for phosphorus removal has in this work been studied both theoretically and experimentally. Thermochemical properties of Ce, Nd, and Pr monophosphides have first been estimated by ab initio thermodynamic simulations based on density functional theory and the direct phonon method. The reliability of the first principles calculations was assessed by coupling with the phase diagram data of the Pr-P system. Equilibrium calculations confirmed the existence of stable rare earth monophosphides in solid silicon. Experimental investigations were then carried out, employing a high temperature resistance furnace. The Ce-doped silicon samples were examined by electron probe micro analyzer and inductively coupled plasma analysis. The efficiency of phosphorus removal by means of rare earth doping was discussed in detail in the paper.

  2. 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

  3. Effect of prefermentation on denitrifying phosphorus removal in slaughterhouse wastewater.

    PubMed

    Merzouki, M; Bernet, N; Delgenès, J P; Benlemlih, M

    2005-08-01

    An anaerobic-anoxic sequencing batch reactor (A2 SBR) coupled with a fixed-bed nitrification reactor for simultaneous carbon, nitrogen and phosphorus removal was evaluated using slaughterhouse wastewater. Whereas the treatment could not be successfully carried out on the raw wastewater, the process showed very good nutrient removal performances after prefermentation. The removals of COD, N-NH4 and P-PO4 achieved were 99%, 85% and 99%, respectively. The increase in volatile fatty acid (VFA) and phosphate concentrations in the effluent after prefermentation may explain the high levels of biological carbon, nitrogen and phosphorus removal observed. A simple prefermentation is, therefore, necessary but sufficient to ensure good performances of the denitrifying enhanced biological phosphorus removal (EBPR) process.

  4. Phosphorus and Nitrogen Co-Limit Global Grassland Productivity

    NASA Astrophysics Data System (ADS)

    Fay, P. A.; Prober, S. M.; Harpole, W. S.; Knops, J. M. H.; Bakker, J. D.; Borer, E. T.; MacDougall, A. S.; Seabloom, E. W.; Wragg, P. D.; Lind, E. M.

    2014-12-01

    Terrestrial ecosystem primary productivity has been considered to be primarily nitrogen (N) - limited, but may be co-limited by phosphorus (P), and possibly by potassium and micronutrients (K+m). The frequency, magnitude, and global extent of single or multiple nutrient limitations are poorly understood in natural systems, but can influence how anthropogenic nutrient enrichment affects ecosystem productivity and provisioning of ecosystem goods and services. We examined the occurrence and magnitude of nutrient limitation of aboveground net primary productivity (ANPP) by N, P, and K+m at 42 grassland sites on five continents in the Nutrient Network (https://www.nutnet.umn.edu). N, P, and K+m were factorially applied annually in a randomized block design at all sites. ANPP was measured annually for 3 to 5 years by clipping and weighing standing aboveground biomass. We found clear evidence for nutrient limitation of ANPP in these grasslands. Across all sites and years, the combined addition of N and P increased ANPP by 39% over controls, more than occurred if either was added alone (N: 18%; P: 9%), suggesting co-limitation of ANPP by both nutrients. Co-limitation by other nutrient combinations was not detected. At individual sites, ANPP limitation was most often alleviated by adding N and P together, but K+m addition alleviated ANPP limitation at three sites. Also, site-level limitation of ANPP by any one nutrient was positively correlated (R2 0.07 to 0.21) with limitation by other single or multiple nutrients, suggesting generalized multiple nutrient limitation. We found no differences in nutrient limitation of ANPP among continents or management practices, between native and previously cultivated grasslands, or with site soil properties or climate. These novel patterns of nutrient limitation of ANPP in grasslands around the global contradict the long-held idea that N is the primary nutrient limiting productivity in these ecosystems. Grasslands are globally important

  5. Past, present, and future use of phosphorus in Chinese agriculture and its influence on phosphorus losses.

    PubMed

    Li, Haigang; Liu, Jian; Li, Guohua; Shen, Jianbo; Bergström, Lars; Zhang, Fusuo

    2015-03-01

    Large inputs of phosphorus (P) in chemical fertilizers and feed supplements since 1978 have improved soil P status in arable land in China, but have also created challenges by increasing P concentrations in manure and exacerbating water quality degradation. Arable land in China can be divided into five management zones based on soil P chemistry, with 15-92 % of arable land having lower P status than the agronomic optimum and 0.3-7.2 % having severe risks of P leaching losses. A scenario analysis of soil P budget and agronomic P demand during 2011-2030 highlighted the great pressure China faces in sustainable P management and the need for drastic changes in current practices. This includes new policies to reduce P supplementation of feed and improved P use efficiency by livestock and programs to expand the adoption of appropriate fertilization, soil conservation, and drainage management practices to minimize P losses.

  6. [Calcium pros and cons significance and risk of phosphorus supplementation. The risk of dietary phosphorus intake].

    PubMed

    Ohi, Akiko; Nomura, Kengo; Miyamoto, Ken-ichi

    2011-12-01

    Dietary intake of phosphorus (Pi) is an important determinant of Pi balance in patients who have chronic kidney disease (CKD) and a reduced GFR. High dietary Pi burden may promote vascular calcification and cardiovascular events. Recently, Ohnishi and Razzaque suggest that phosphate toxicity accelerates the mammalian aging process and that reducing the phosphate burden can delay the aging (FASEB J 24, 3562, 2010) . Dietary Pi is derived largely from foods with high protein content or food additives. Accurate information on the Pi content of foods is needed to achieve a low Pi intake and effectively manage CKD and the aging. In this review, we discuss the risk of dietary Pi intake in CKD and the aging.

  7. 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 μm 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 < k{sub p} < 1.1 and a diffusion coefficient D = 1.4(±0.2)cm{sup 2}/s × 10{sup −3 }× exp[−183 meV/(k{sub B}T)].

  8. 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

  9. 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 μM), whereas the high P concentration (50 μM) 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 μM 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

  10. 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 μM), whereas the high P concentration (50 μM) 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 μM 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.

  11. The fluvial flux of phosphorus from the UK 1974 - 2012: where has all the phosphorus gone?

    NASA Astrophysics Data System (ADS)

    Worrall, Fred; Howden, Nicholas; Burt, Timothy; Jarvie, Helen

    2015-04-01

    As part of the Harmonised Monitoring Scheme, the UK has been monitoring total phosphorus (TP) and total reactive phosphorus (TRP) concentration at the tidal limit of all major UK rivers since 1974. Over the study period there were over 40,000 measurements of TP from 230 catchments and 160,000 measurements of TRP from 270 catchments. Concentrations of TRP and TP in UK rivers have decreased significantly since 1989, with values now less than 50% of their 1974 values. During this time, the ratio of TRP to TP has increased slightly with TRP now representing 73% of TP. The UK riverine flux of TRP peaked at 70.9 ktonnes P/yr (0.29 tonnes P/km2/yr) in 2000 and reached a minimum in 2011 of 9.3 ktonnes P/yr (0.04 tonnes P/km2/yr). Similarly, for TP, the peak flux occurred in 2001 at 95 ktonnes P/yr, with a minimum in 2011 of 15.8 ktonnes P/yr. A comparison of patterns in P fluxes with catchment land-use, soil types and hydroclimatic factors shows that the fluxes of both TP and TRP are dominantly linked to urban land cover, which we consider to be proxy for sewage inputs. The fluvial fluxes of TRP and TP will be discussed in the light of declining P fertiliser inputs; decreased direct sewage outputs of P; increased transfers of P via food and feed imports; and an increasing UK population.

  12. Multiple myeloma on polycythemia vera following radioactive phosphorus therapy.

    PubMed

    West, W O

    1976-11-01

    A 74-year-old white man with established polycythemia vera was treated with radioactive phosphorus after phlebotomies alone failed to control his disease. About 2 3/4 years later he died of multiple myeloma. The mutagenic effect of radioactive phosphorus may have caused or possibly accelerated preexisting myeloma. Basic nonmalignant disease deserves careful consideration before radiation or radiomimetic agents are used. One might consider a probably less mutagenic drug such as hydroxyurea in patients with polycythemia vera when phlebotomy alone does not give good control of red cell mass and thrombocytosis.

  13. 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.

  14. Surface structure determination of black phosphorus using photoelectron diffraction

    NASA Astrophysics Data System (ADS)

    de Lima, Luis Henrique; Barreto, Lucas; Landers, Richard; de Siervo, Abner

    2016-01-01

    The atomic structure of single-crystalline black phosphorus is studied using high-resolution synchrotron-based photoelectron diffraction (XPD). The results show that the topmost phosphorene layer in the black phosphorus is slightly displaced compared to the bulk structure and presents a small contraction in the direction perpendicular to the surface. Furthermore, the XPD results show the presence of a small buckling among the surface atoms, in agreement with previously reported scanning tunneling microscopy results. The contraction of the surface layer added to the presence of the buckling indicates a uniformity in the size of the s p3 bonds between P atoms at the surface.

  15. 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.

  16. Lateral transport of phosphorus along forested hillslopes

    NASA Astrophysics Data System (ADS)

    Sohrt, Jakob; Weiler, Markus; Puhlmann, Heike

    2016-04-01

    Details about the phosphorus (P)-cycle in temperate forests are still incomplete, though there are indications that the organic topsoil acts as an important source and sink for P. It can act as a sink for P in fallen litter and as a source since the decaying biomass replenishes the pool of inorganic, water soluble and thus plant available P. The aim of this study was to determine the magnitude of lateral mobilization, transport and retention of total P (persulfate digestion method) in the soil at various depths of a broadleaf forest during heavy rainstorm events. On three locations in Germany, 10 m long and over 3m deep trenches were constructed to collect lateral subsurface flow from three discrete depth-layers between the soil surface and a depth of three meters. Sampling is handled through an automated system which collects flow-proportional samples in high temporal resolution. Sampling took place from March to November 2015 including more than 20 rainfall runoff events. Simultaneously to the sampling, flow rate, conductivity and temperature of the interflow was measured as well as soil moisture, rainfall and discharge in the nearest downslope spring. The results show consistently that P-concentrations in interflow samples are highest at the beginning of a rainfall-interflow-event, both for wet and dry initial conditions, and drop considerably over the course of the event until they stabilize. Secondly, P-concentration of interflow samples is by far highest in the organic topsoil, being up to one magnitude higher that in the mineral soil directly below and decreasing further with depth. This pattern applies despite the fact that there is very little temporal delay between the activation of interflow in the topsoil and deeper layers which indicates that at least some of the interflow in the topsoil ends up as interflow in deeper layers within a short time span. These results indicate that the organic topsoil contains a pool of P that is easily mobilized and

  17. Removal of phosphorus from livestock effluents.

    PubMed

    Szogi, Ariel A; Vanotti, Matias B

    2009-01-01

    For removal of phosphorus (P) from swine liquid manure before land application, we developed a treatment process that produces low P effluents and a valuable P by-product with minimal chemical addition and ammonia losses. The new wastewater process included two sequential steps: (i) biological nitrification and (ii) increasing the pH of the nitrified wastewater to precipitate P. We hypothesized that by reduction of inorganic buffers (NH(4)(+) and carbonate alkalinity) via nitrification, P could be selectively removed by subsequent hydrated lime [Ca(OH)(2)] addition. The objective of the study was to assess if this new treatment could consistently reduce inorganic buffer capacity with varied initial concentrations of N (100-723 mg NH(4)(+) L(-1)), P (26-85 mg TP L(-1)), and alkalinity (953-3063 mg CaCO(3) L(-1)), and then efficiently remove P from swine lagoon liquid. The process was tested with surface lagoon liquids from 10 typical swine farms in North Carolina. Each lagoon liquid received treatment in a nitrification bioreactor, followed by chemical treatment with Ca(OH)(2) at Ca rates of 0, 2, 4, 6, 8, 10, and 12 mmol L(-1) to precipitate P. This configuration was compared with a control that received the same Ca rates but without the nitrification pretreatment. The new process significantly reduced >90% the inorganic buffers concentrations compared with the control and prevented ammonia losses. Subsequent lime addition resulted in efficient pH increase to > or = 9.5 for optimum P precipitation in the nitrified liquid and significant reduction of effluent total P concentration versus the control. With this new process, the total P concentration in treated liquid effluent can be adjusted for on-farm use with up to >90% of P removal. The recovered solid Ca phosphate material can be easily exported from the farm and reused as P fertilizer. Therefore, the new process can be used to reduce the P content in livestock effluents to levels that would diminish problems of

  18. Dietary phosphorus excess: a risk factor in chronic bone, kidney, and cardiovascular disease?

    PubMed

    Uribarri, Jaime; Calvo, Mona S

    2013-01-01

    There is growing evidence in the nephrology literature supporting the deleterious health effect of excess dietary phosphorus intake. This issue has largely escaped the attention of nutrition experts until this symposium, which raised the question of whether the same health concerns should be extended to the general population. The potential hazard of a high phosphorus intake in the healthy population is illustrated by findings from acute and epidemiologic studies. Acute studies in healthy young adults demonstrate that phosphorus intakes in excess of nutrient needs may significantly disrupt the hormonal regulation of phosphorus contributing to disordered mineral metabolism, vascular calcification, bone loss, and impaired kidney function. One of the hormonal factors acutely affected by dietary phosphorus loading is fibroblast growth factor-23, which may be a key factor responsible for many of the cardiovascular disease (CVD) complications of high phosphorus intake. Increasingly, large epidemiological studies suggest that mild elevations of serum phosphorus within the normal range are associated with CVD risk in healthy populations. Few population studies link high dietary phosphorus intake to mild changes in serum phosphorus due to study design issues specific to phosphorus and inaccurate nutrient composition databases. The increasing phosphorus intake due to the use of phosphorus-containing ingredients in processed food and the growing consumption of processed convenience and fast foods is an important factor that needs to be emphasized.

  19. 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...

  20. Assessing the Health Impact of Phosphorus in the Food Supply: Issues and Considerations123

    PubMed Central

    Calvo, Mona S.; Moshfegh, Alanna J.; Tucker, Katherine L.

    2014-01-01

    The Western dietary pattern of intake common to many Americans is high in fat, refined carbohydrates, sodium, and phosphorus, all of which are associated with processed food consumption and higher risk of life-threatening chronic diseases. In this review, we focus on the available information on current phosphorus intake with this Western dietary pattern, and new knowledge of how the disruption of phosphorus homeostasis can occur when intake of phosphorus far exceeds nutrient needs and calcium intake is limited. Elevation of extracellular phosphorus, even when phosphorus intake is seemingly modest, but excessive relative to need and calcium intake, may disrupt the endocrine regulation of phosphorus balance in healthy individuals, as it is known to do in renal disease. This elevation in serum phosphate, whether episodic or chronically sustained, may trigger the secretion of regulatory hormones, whose actions can damage tissue, leading to the development of cardiovascular disease, renal impairment, and bone loss. Therefore, we assessed the health impact of excess phosphorus intake in the context of specific issues that reflect changes over time in the U.S. food supply and patterns of intake. Important issues include food processing and food preferences, the need to evaluate phosphorus intake in relation to calcium intake and phosphorus bioavailability, the accuracy of various approaches used to assess phosphorus intake, and the difficulties encountered in evaluating the relations of phosphorus intake to chronic disease markers or incident disease. PMID:24425729

  1. 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...

  2. 40 CFR Appendix A to Part 80 - Test for the Determination of Phosphorus in Gasoline

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... stock standard phosphorus solution into a 1000-ml volumetric flask and dilute to the mark with water. 5... Phosphorus in Gasoline A Appendix A to Part 80 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY... 80—Test for the Determination of Phosphorus in Gasoline 1. Scope. 1.1 This method was developed...

  3. 40 CFR Appendix A to Part 80 - Test for the Determination of Phosphorus in Gasoline

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... stock standard phosphorus solution into a 1000-ml volumetric flask and dilute to the mark with water. 5... Phosphorus in Gasoline A Appendix A to Part 80 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY... 80—Test for the Determination of Phosphorus in Gasoline 1. Scope. 1.1 This method was developed...

  4. 40 CFR Appendix A to Part 80 - Test for the Determination of Phosphorus in Gasoline

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... stock standard phosphorus solution into a 1000-ml volumetric flask and dilute to the mark with water. 5... Phosphorus in Gasoline A Appendix A to Part 80 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY... 80—Test for the Determination of Phosphorus in Gasoline 1. Scope. 1.1 This method was developed...

  5. 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...

  6. 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

  7. Dietary phosphorus excess: a risk factor in chronic bone, kidney, and cardiovascular disease?

    PubMed

    Uribarri, Jaime; Calvo, Mona S

    2013-01-01

    There is growing evidence in the nephrology literature supporting the deleterious health effect of excess dietary phosphorus intake. This issue has largely escaped the attention of nutrition experts until this symposium, which raised the question of whether the same health concerns should be extended to the general population. The potential hazard of a high phosphorus intake in the healthy population is illustrated by findings from acute and epidemiologic studies. Acute studies in healthy young adults demonstrate that phosphorus intakes in excess of nutrient needs may significantly disrupt the hormonal regulation of phosphorus contributing to disordered mineral metabolism, vascular calcification, bone loss, and impaired kidney function. One of the hormonal factors acutely affected by dietary phosphorus loading is fibroblast growth factor-23, which may be a key factor responsible for many of the cardiovascular disease (CVD) complications of high phosphorus intake. Increasingly, large epidemiological studies suggest that mild elevations of serum phosphorus within the normal range are associated with CVD risk in healthy populations. Few population studies link high dietary phosphorus intake to mild changes in serum phosphorus due to study design issues specific to phosphorus and inaccurate nutrient composition databases. The increasing phosphorus intake due to the use of phosphorus-containing ingredients in processed food and the growing consumption of processed convenience and fast foods is an important factor that needs to be emphasized. PMID:24038251

  8. 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...

  9. 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…

  10. Meta-analysis of phosphorus utilization by growing pigs: effect of dietary phosphorus, calcium and exogenous phytase.

    PubMed

    Létourneau-Montminy, M P; Jondreville, C; Sauvant, D; Narcy, A

    2012-10-01

    Optimizing phosphorus (P) utilization in pigs requires improving our capacity to predict the amount of P absorbed and retained, with the main modulating factors taken into account, as well as precisely determining the P requirements of the animals. Given the large amount of published data on P utilization in pigs, a meta-analysis was performed to quantify the impact of the different dietary P forms, calcium (Ca) and exogenous phytases on the digestive and metabolic utilization criteria for dietary P in growing pigs. Accordingly, the amount of phytate P (PP) leading to digestible P (g/kg) was estimated to be 21%, compared with 73% for non-phytate P (NPP) from plant ingredients and 80% for NPP from mineral and animal ingredients (P < 0.001). The increase in total digestible dietary P following the addition of microbial phytase (PhytM) from Aspergillus niger (P < 0.001) was curvilinear and about two times higher than the increase following the addition of plant phytase, which leads to a linear response (P < 0.001). The response of digestible P to PhytM also depends on the amount of substrate, PP (PhytM(2) × PP, P < 0.001). The digestibility of dietary P decreased with dietary Ca concentration (P < 0.01) independently of phytase but increased with body weight (BW, P < 0.05). Although total digestible dietary P increased linearly with total NPP concentration (P < 0.001), retained P (g/kg), average daily gain (ADG, g/day) and average daily feed intake (ADFI, g/day) increased curvilinearly (P < 0.001). Interestingly, whereas dietary Ca negatively affected P digestibility, the effect of dietary Ca on retained P, ADG and ADFI depended on total dietary NPP (NPP × Ca, P < 0.01, P < 0.05 and P < 0.01, respectively). Increasing dietary Ca reduced retained P, ADG and ADFI at low NPP levels, but at higher NPP concentrations it had no effect on ADG and ADFI despite a positive effect on retained P. Although the curvilinear effect of PhytM on digestible P increased with PP (P < 0

  11. Effect of dietary phosphorus on the growth and body components of juvenile Synechogobius hasta

    NASA Astrophysics Data System (ADS)

    Luo, Zhi; Li, Xiaodong; Gong, Shiyuan; Xi, Wenqiu; Li, Yali

    2009-03-01

    The effect of dietary phosphorus on the growth and body components of juvenile Synechogobius hasta was determined. Different percentages of dietary phosphorus (0.63, 0.77, 0.93, 1.06, 1.22 and 1.36) were tested by feeding the fish (body weight, 15.81 g ± 0.32 g; 20 individuals each group; 3 groups each percentage) at a surplus of 5%-10% above satiation for 35 d. Dietary phosphorus did not significantly affect the specific growth rate, feed intake, feed conversion ratio and protein efficiency rate. Nitrogen retention was found to be the highest in fish fed the diet containing 1.06% of phosphorus; however, this was not significantly different from other diets. Fish fed the diet containing 0.93% of phosphorus showed the highest phosphorus retention; similar phosphorus retention rates were found in fish fed the diets containing 0.77% and 1.06% of phosphorus. Fish fed the diet containing the highest percentage of dietary phosphorus were found to contain the least whole body lipid, lower than fish fed other diets ( P<0.05). The protein content increased from 18.59% to 19.55% (although not significant) with the decrease of body lipid content ( P>0.05). The contents of the whole body ash, whole body phosphorus and vertebrae phosphorus increased with dietary phosphorus percentage up to 1.06 ( P<0.05), reaching a plateau after that. Dietary phosphorus did not significantly influence the muscle components (protein, lipid and moisture). Condition factor and hepatosomatic index were the highest in fish fed the diet containing 0.63% of dietary phosphorus; however, this was not significantly different from those of other diets. The second-order polynomial regression of phosphorus retention against dietary phosphorus identified a breakpoint at 0.88% of dietary phosphorus. However, the dietary requirement of phosphorus for maintaining maximum phosphorus storage determined by broken-line analysis of the contents of whole body phosphorus, and ash and vertebrae phosphorus was 1

  12. Downregulation of net phosphorus-uptake capacity is inversely related to leaf phosphorus-resorption proficiency in four species from a phosphorus-impoverished environment

    PubMed Central

    de Campos, Mariana C. R.; Pearse, Stuart J.; Oliveira, Rafael S.; Lambers, Hans

    2013-01-01

    Background and Aims Previous research has suggested a trade-off between the capacity of plants to downregulate their phosphorus (P) uptake capacity and their efficiency of P resorption from senescent leaves in species from P-impoverished environments. Methods To investigate this further, four Australian native species (Banksia attenuata, B. menziesii, Acacia truncata and A. xanthina) were grown in a greenhouse in nutrient solutions at a range of P concentrations [P]. Acacia plants received between 0 and 500 µm P; Banksia plants received between 0 and 10 µm P, to avoid major P-toxicity symptoms in these highly P-sensitive species. Key Results For both Acacia species, the net P-uptake rates measured at 10 µm P decreased steadily with increasing P supply during growth. In contrast, in B. attenuata, the net rate of P uptake from a solution with 10 µm P increased linearly with increasing P supply during growth. The P-uptake rate of B. menziesii showed no significant response to P supply in the growing medium. Leaf [P] of the four species supported this finding, with A. truncata and A. xanthina showing an increase up to a saturation value of 19 and 21 mg P g−1 leaf dry mass, respectively (at 500 µm P), whereas B. attenuata and B. menziesii both exhibited a linear increase in leaf [P], reaching 10 and 13 mg P g−1 leaf dry mass, respectively, without approaching a saturation point. The Banksia plants grown at 10 µm P showed mild symptoms of P toxicity, i.e. yellow spots on some leaves and drying and curling of the tips of the leaves. Leaf P-resorption efficiency was 69 % (B. attenuata), 73 % (B. menziesii), 34 % (A. truncata) and 36 % (A. xanthina). The P-resorption proficiency values were 0·08 mg P g−1 leaf dry mass (B. attenuata and B. menziesii), 0·32 mg P g−1 leaf dry mass (A. truncata) and 0·36 mg P g−1 leaf dry mass (A. xanthina). Combining the present results with additional information on P-remobilization efficiency and the capacity to

  13. Phosphorus use-efficiency of agriculture and food system in the US.

    PubMed

    Suh, Sangwon; Yee, Scott

    2011-08-01

    The rapid increase in human mobilization of phosphorus has raised concerns on both its supply security and its impact on the environment. Increasing the efficiency of phosphorus use is an approach to mitigate the adverse impacts associated with phosphorus consumption. This study estimates the life-cycle phosphorus use-efficiency of the US food system. A framework for accounting phosphorus stocks and flows is developed, and the account was populated with data. A map of phosphorus stocks and flows around the US food system is drawn and phosphorus use-efficiency was calculated. The results show that only 15% of the total phosphorus extracted from nature for the provision of food is eventually ingested by humans and the rest is lost to the environment. Major losses occur during the livestock, meat and dairy production and crop cultivation stage, where about 66% of the total phosphorus extracted is lost to the environment. The results also show that other losses of phosphorus including household food waste, mining waste, and fertilizer manufacturing waste are not negligible, which constitute about 19% of the total phosphorus extracted for food purpose. A data quality assessment and sensitivity analysis was performed to identify data quality hotspots and to envisage effective measures to improving phosphorus use-efficiency. Improving yields of livestock and crop cultivation without additional phosphorus input and reducing household food waste are shown to be effective measures to improve life-cycle phosphorus use-efficiency. The results highlight the need of a concerted effort by all entities along the life-cycle for efficient use of phosphorus. PMID:21333320

  14. Phosphorus use-efficiency of agriculture and food system in the US.

    PubMed

    Suh, Sangwon; Yee, Scott

    2011-08-01

    The rapid increase in human mobilization of phosphorus has raised concerns on both its supply security and its impact on the environment. Increasing the efficiency of phosphorus use is an approach to mitigate the adverse impacts associated with phosphorus consumption. This study estimates the life-cycle phosphorus use-efficiency of the US food system. A framework for accounting phosphorus stocks and flows is developed, and the account was populated with data. A map of phosphorus stocks and flows around the US food system is drawn and phosphorus use-efficiency was calculated. The results show that only 15% of the total phosphorus extracted from nature for the provision of food is eventually ingested by humans and the rest is lost to the environment. Major losses occur during the livestock, meat and dairy production and crop cultivation stage, where about 66% of the total phosphorus extracted is lost to the environment. The results also show that other losses of phosphorus including household food waste, mining waste, and fertilizer manufacturing waste are not negligible, which constitute about 19% of the total phosphorus extracted for food purpose. A data quality assessment and sensitivity analysis was performed to identify data quality hotspots and to envisage effective measures to improving phosphorus use-efficiency. Improving yields of livestock and crop cultivation without additional phosphorus input and reducing household food waste are shown to be effective measures to improve life-cycle phosphorus use-efficiency. The results highlight the need of a concerted effort by all entities along the life-cycle for efficient use of phosphorus.

  15. The research of phosphorus of Xiangxi River nearby the Three Gorges, China

    NASA Astrophysics Data System (ADS)

    Fu, Chang-Ying; Fang, Tao; Deng, Nan Sheng

    2006-03-01

    The Xiangxi River is the first middling tributary of the Changjiang River near the Three Gorges Dam. The River is subject to phosphorus pollution mainly from industrial wastewater. As the water quality of the Xiangxi River could directly influence the water quality of the Three Gorges Reservoir, the research on phosphorus levels and its change in the sediment profile of the Xiangxi River could provide useful information in the dynamic changes in the system, thereby offering options for mitigative measures. Water and sediment samples from lower reaches of Xiangxi River were collected and the different forms of phosphorus in sediments of the Xiangxi River were studied. The concentrations of total phosphorus in sediment ranged from 757.67 to 1438.54 mg/kg. Inorganic phosphorus concentrations ranged from 684.63 to 1055.58 mg/kg. Phosphorus contamination was serious in some parts of the Xiangxi River. With an average concentration of 635.17 mg/kg, calcium-bound phosphorus is the main form among different inorganic phosphorus forms. Labile phosphorus and iron/aluminum-bound phosphorus measured 3.40, 0.05and 35.28 mg/kg, respectively. The mobilization potential of phosphorus of sediments was studied through adsorption and release experiments. The equilibrium concentration of phosphorus adsorption and release was around 0.1 mg/L. The initial concentrations of phosphorus in the overlying water and the sediments have obvious effect on phosphorus mobilization potential. In addition, the release rate of phosphorus in sediment increased with water depth.

  16. Phosphorus Chemistry and Bacterial Community Composition Interact in Brackish Sediments Receiving Agricultural Discharges

    PubMed Central

    Sinkko, Hanna; Sihvonen, Leila M.; Sivonen, Kaarina; Leivuori, Mirja; Rantanen, Matias; Paulin, Lars; Lyra, Christina

    2011-01-01

    Background External nutrient discharges have caused eutrophication in many estuaries and coastal seas such as the Baltic Sea. The sedimented nutrients can affect bacterial communities which, in turn, are widely believed to contribute to release of nutrients such as phosphorus from the sediment. Methods We investigated relationships between bacterial communities and chemical forms of phosphorus as well as elements involved in its cycling in brackish sediments using up-to-date multivariate statistical methods. Bacterial community composition was determined by terminal restriction fragment length polymorphism and cloning of the 16S rRNA gene. Results and Conclusions The bacterial community composition differed along gradients of nutrients, especially of different phosphorus forms, from the estuary receiving agricultural phosphorus loading to the open sea. This suggests that the chemical composition of sediment phosphorus, which has been affected by riverine phosphorus loading, influenced on bacterial communities. Chemical and spatial parameters explained 25% and 11% of the variation in bacterial communities. Deltaproteobacteria, presumptively sulphate and sulphur/iron reducing, were strongly associated to chemical parameters, also when spatial autocorrelation was taken into account. Sulphate reducers correlated positively with labile organic phosphorus and total nitrogen in the open sea sediments. Sulphur/iron reducers and sulphate reducers linked to iron reduction correlated positively with aluminium- and iron-bound phosphorus, and total iron in the estuary. The sulphate and sulphur/iron reducing bacteria can thus have an important role both in the mineralization and mobilization of nutrients from sediment. Significance Novelty in our study is that relationships between bacterial community composition and different phosphorus forms, instead of total phosphorus, were investigated. Total phosphorus does not necessarily bring out interactions between bacteria and

  17. 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...

  18. Phosphorus-bearing Molecules in Massive Dense Cores

    NASA Astrophysics Data System (ADS)

    Fontani, F.; Rivilla, V. M.; Caselli, P.; Vasyunin, A.; Palau, A.

    2016-05-01

    Phosphorus is a crucial element for the development of life, but so far P-bearing molecules have been detected only in a few astrophysical objects; hence, its interstellar chemistry is almost totally unknown. Here, we show new detections of phosphorus nitride (PN) in a sample of dense cores in different evolutionary stages of the intermediate- and high-mass star formation process: starless, with protostellar objects, and with ultracompact H ii regions. All detected PN line widths are smaller than ≃5 km s-1, and they arise from regions associated with kinetic temperatures smaller than 100 K. Because the few previous detections reported in the literature are associated with warmer and more turbulent sources, the results of this work show that PN can arise from relatively quiescent and cold gas. This information is challenging for theoretical models that invoke either high desorption temperatures or grain sputtering from shocks to release phosphorus into the gas phase. Derived column densities are of the order of 1011-12 cm-2, marginally lower than the values derived in the few high-mass star-forming regions detected so far. New constraints on the abundance of phosphorus monoxide, the fundamental unit of biologically relevant molecules, are also given. Based on observations carried out with the IRAM-30 m Telescope. IRAM is supported by INSU/CNRS (France), MPG (Germany), and IGN (Spain).

  19. Laboratory Studies Of Astrophysically-interesting Phosphorus-bearing Molecules

    NASA Astrophysics Data System (ADS)

    Ziurys, Lucy M.; Halfen, D. T.; Sun, M.; Clouthier, D. J.

    2009-05-01

    Over the past year, there has been a renewed interest in the presence of phosphorus-containing molecules in the interstellar medium. Recent observations have increased the number of known interstellar phosphorus-bearing species from two (PN, CP) to six with the identification of HCP, CCP, and PH3 in the carbon-rich circumstellar shell of IRC+10216 and PO in the oxygen-rich envelope of VY Canis Majoris. More species of this type may be present in the ISM, but laboratory rest frequencies, necessary for such detections, are not generally known for many potential molecules. To fill in this gap, we have been conducting measurements of the pure rotational spectra of phosphorus-containing molecules of astrophysical interest, using both millimeter/submm direct absorption and Fourier transform microwave (FTMW) spectroscopy. We have developed a new phosphorus source for this purpose. These methods cover the frequency ranges 65-850 GHz and 4-40 GHz, respectively. Our recent study of the CCP radical (X2Πr) using both of these techniques has resulted in its identification in IRC+10216. Rotational spectra of other molecules such as PCN, HPS, and CH3PH2 have been recorded. We will report on these species and additional new laboratory developments

  20. Phosphorus losses from agricultural watersheds in the Mississippi Delta

    Technology Transfer Automated Retrieval System (TEKTRAN)

    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 2000) for three agric...