Effects Of Phosphorus Addition Research Articles

Influence of Phosphorus on Solidification Structure in Continuously Cast 0.1 mass% Carbon Steel.

In 0.1 mass% carbon steels with phosphorus contents ranging from 0.01 to 0.2 mass%, slabs were continuously cast to a thickness of 100 mm with a laboratory scale caster. Their macro- and micro-structures were characterized, focusing on the effects of phosphorus addition on the structural evolution during solidification and subsequent cooling. Cast slabs of high phosphorus steels have a fine columnar-γ-grain structure. The mean width of the columnar grain was approximately half of that in the cast slabs without the phosphorus addition. Dispersed globular a grains were observed in the a grain structure of high phosphorus steels. The globular grains evolved at the phosphorus-rich spots in the prior-y grain. The micro-segregation of phosphorus results in these structural evolutions. Since the phosphorus enrichment stabilizes bcc (δ or α) phase locally at the inter-dendritic region, the phosphorus-rich spot makes δ phase retained to lower temperature for the δ/γ transformation, and provides a predominant site for the y/a transformation. In the high phosphorus casts, therefore, the dispersed δ phase are thought to pin the y grain growth more effectively in the δ+ γ region when the completion of the δ/γ transformation is remarkably suppressed by the phosphorus segregation.

Effects of Phosphorus Additions on Lead, Cadmium, and Zinc Bioavailabilities in a Metal-Contaminated Soil

The use of phosphorus (P) to reduce lead (Pb)bioavailability is being proposed as an alternative to excavationand disposal as a remedial technology for Pb-contaminated soilsin residential areas. The objective of this study was todetermine the influence of P sources and rates andCaCO3additions on the bioavailabilities of Pb, cadmium (Cd), and zinc(Zn) in a contaminated soil material using plants, a sequentialextraction procedure, and ion activities in equilibrium solutionas indicators. A contaminated soil containing 370 mg kg-1 Cd, 2800 mg kg-1 Pb and 29100 mg kg-1 Zn was amended ina factorial arrangement of CaCO3 (0 or 2000 mg kg-1) and P as rock phosphate or KH2PO4 at 0:1, 2:1 or 4:1P:Pb mole ratios. A pot study was conducted using sorghum-sudangrass (Sorghum bicolor L. Moench). The addition of P did not influence Pb concentrations in plant tissue and had little effect on Cd concentrations. An interaction between P source and level of P addition was found for Zn concentrations in plant tissue; concentrations increased with increasing amounts of P from KH2PO4 anddecreased with increasing amounts of P from rock phosphate. Sequential extraction results suggested a much greater reduction in Pb bioavailability from treatment withKH2PO4 than with rock phosphate and that P influencedthe fractionations of Cd and Zn. Activities of Cd2+,Pb2+, and Zn2+ in equilibrium solutions generally weredecreased by rock phosphate and increased by KH2PO4. Saturation indices suggested the addition ofKH2PO4shifted the soil equilibrium from octavite to hydroxypyromorphite, whereas solid-phase control of Cd2+ andZn2+ was not influenced by soil amendments. A soluble Psource was more effective in reducing Pb bioavailability thanrock phosphate but had variable effects on Cd and Znbioavailabilities.

Effects of Phosphorus Additions on Growth, Mineral Nutrition, and Gas Exchange of Red Alder (Alnus rubra) Seedlings Grown in Outdoor Sandbeds

Abstract The growth of young red alder on Vancouver Island may increase with phosphorus (P) availability. In order to better interpret growth responses in field fertilization trials, this study examined the effects of P additions (10, 100, 200, or 400 kg P/ha) on the growth and nutrient uptake of red alder seedlings grown in outdoor sandbeds for one growing season. Height did not increase with P supply. Stem growth and whole-plant mass increased with P rate from 10 to 100 kg/ha, but did not increase further at greater rates of P addition. Stem volumes, averaged across the P100, P200 and P400 treatments, were 37% greater than in the P10 treatment. Volume and mass did not increase as foliar P concentrations exceeded 2.2 g P/kg. These responses were consistent with data from field trials. Reduced growth in the P10 treatment was not accompanied by significantly reduced foliar P concentrations. Increases in stem volume with P supply were associated with increases in the amount of branching and foliage borne on branches but not with shifts in allocation of dry matter from roots to shoots. West. J. Appl. For. 17(4):209–215.

Fate and effects of phosphorus additions in soils under N2-fixing red alder

Soil phosphorus (P) dynamics are controlled by the interaction of geochemical, biochemical and biological processes. Changes in species composition or management could alter the relative importance of these processes. We examined soil P dynamics in two plantations of N2-fixing red alder (Alnus rubra) by determining the fate and effects of added fertilizer P. History of the plantations varied such that sites were previously occupied by 60-yr-old stands of alder or non-fixing Douglas-fir (Pseudotsuga menziesii). Without fertilization, the soil with a longer period of alder influence had more organic P (Po) and less sorbed inorganic P (Hydroxide- and Bicarb-extractable Pi). Fertilization increased soil total P, and 88% of the fertilizer was accounted for in the surface mineral soil (0–15 cm). Sorbed Pi was the major sink for fertilizer P (55–60%), independent of site history. Although Po was 35–70% of soil P in unfertilized plots, added P did not accumulate as Po. Neither site history nor P addition influenced phosphatase activity. Fertilization increased decomposition during incubation of the organic horizon, suggesting that late-stage decomposition is P-limited in these N-rich soils. On the time-scale of a few years, geochemical sorption and desorption of inorganic P were the most important processes controlling the distribution of added P. Organic P accumulation is expected to occur over a longer time frame, linked to the production and turnover of organic matter.

Effect of phosphorus additions on the spacing between primary silicon particles in a Bridgman solidified hypereutectic Al-Si alloy

The effect of 100 ppm addition of phosphorus on primary silicon particle number density per unit area NA and corresponding interparticle spacing λ is reported for a Bridgman solidified Al-20 wt%Si base alloy. The phosphorus (added as Al-Fe-P base or Al-Cu-P alloys) results in a factor of 3 increase in NA and a factor of 2 reduction in λ for the range of conditions studied. In its absence the results conform to λ\(\dot T^{1/3} \) = 256 ± 24 μm (K/s)1/3 where \(.dot T\) is cooling rate during solidification in good agreement with earlier data. When published data on the effect of 0.02 to 0.2 wt%P are included the combined results are well represented by λ\(\dot T^{1/3} \) = 250 − 215 (wt%P)0.17 (λ in μm, \(.dot T\) in K/s).

Effect of Phosphorus Additives on the Metabolome in Healthy Adults

Effect of Phosphorus Additives on the Metabolome in Healthy Adults

XRD Investigations of the Phosphorus Effect on the Oxidation of TiAl Alloys by High-Resolution Methods

Recently it has been found that very small amounts (a few 100 ppm) of Padded to γ -titanium aluminide can significantly alter the oxidationbehavior between 973 and 1273 K. The mechanism responsible for this changeis, however, still not clear. In the present study, phosphorus wasincorporated into the surface of TiAl (containing 50 at.% Al) by ionimplantation and oxidation tests were carried out at 1173 K inair. Improvement of oxidation resistance is only temporary up to 100 hr forphosphorus-implanted TiAl. After 100 hr, the oxidation rate increases andbreakaway oxidation follows. XRD and EPMA showed that the breakawayoxidation is connected with massive nitride formation. Two different modelsare proposed which can explain the effect of phosphorus additions on theoxidation kinetics of TiAl during the protective stage within the first100 hr. The breakaway effect can be explained by penetration of air to themetal–oxide interface zone because of microcrack formation in theoxide scale, which was experimentally proved by acoustic-emission analysis.

Effect of phosphorus addition on the behavior of CoMoS/Al 2O 3 catalyst in hydrodesulfurization of dibenzothiophene and 4,6-dimethyldibenzothiophene

The hydrodesulfurization (HDS) activity of phosphorus-added CoMoS/Al 2O 3 catalysts has been examined using dibenzothiophene (DBT) and 4,6-dimethyldibenzothiophene (4,6-DMDBT) as reactants. Phosphorus modifies catalytic behavior in two ways: increase of active sites by enhanced metal dispersion and increase of Brönsted acidity. These effects yield a different distribution of products depending on the reactants. In thiophene HDS, phosphorus increases only the conversion. In DBT HDS, phosphorus increases the conversion and produces more cyclohexylbenzene (CHB) than biphenyl (BP). In 4,6-DMDBT HDS, the conversion also increases but more dimethylbiphenyl (DMBP) is produced than methylcyclohexyltoluene (MCHT), the opposite trend from the one observed in DBT HDS. This is due to enhanced acidity of the catalyst, which allows migration of the methyl groups in 4,6-DMDBT. Maximum conversions are obtained when the phosphorus content is proper, 0.5 wt.% in this study.

Effect of phosphorus additions on structure formation in materials of the system Cr3C2−TiN−Ni−P

The effect of phosphorus additions on structure formation in materials of the system Cr3C2−TiN−Ni−P is studied. It is established that phosphorus additions as a surface-active element promote an improvement in nickel alloy adhesion properties.

Effect of phosphorus addition on nutrient removal from wastewater with the cyanobacterium Phormidium bohneri

The growth and inorganic nutrient removal capacity of the cyanobacterium Phormidium bohneri on domestic wastewater were investigated in outdoor 24-l triangular bioreactors with or without the presence of added inorganic phosphate. While the addition of monopotassium phosphate did result in up to 56% more biomass production and had an influence on the kinetics of the removal of inorganic nutrients, it did not significantly affect the total time taken for complete removal of these nutrients. In all cases, nitrogen (ammonium and nitrate) and phosphate were removed after 50 and 75 h of growth, respectively. Biomass productivities of 23–57 mg d.m. l −1 day −1, combined with rates of ammonium and phosphate removal up to 20 mg l −1 day −1 indicated that P. bohneri has a good potential for wastewater treatment. In the presence of added phosphate, after 40 h of growth, rates of phosphate removal became erratic, with peaks of phosphate appearing at the beginning of the daylight. These results were interpreted in relation to the complex dynamic equilibrium existing between different forms of phosphate.

ChemInform Abstract: Effect of Phosphorus Addition on the Corrosion Behavior of Arc‐Melted Ni‐10Ta‐P Alloys in 12 M HCl.

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

The effect of phosphorus addition on the corrosion behavior of ARC-MELTED Ni10TaP alloys in 12 M HCl

The corrosion resistance of arc-melted Ni10TaP alloys containing 0, 10 and 20 at% phosphorus in 12 M HCl solution at 30 °C was investigated. The alloys containing 0 and 10 at% phosphorus suffer severe corrosion. The addition of 20 at% phosphorus to crystalline Ni10Ta alloy results in a three-orders-of-magnitude decrease in the corrosion rate. The open circuit potentials of the Ni10Ta alloys containing 0 and 10 at% phosphorus stay almost constant in the active region of nickel, while the open circuit potential of the Ni10Ta20P alloy increases almost linearly in the initial 2 h. The Ni10Ta alloy consists of intermetallic Ni 8Ta and immersion in 12 M HCl results in faceting dissolution. Ni10Ta10P alloy is composed of major Ni 8Ta and Ni 3P phases and minor Ni 2Ta and Ni 2P phases. Immersion of Ni10Ta10P alloy leads to preferential dissolution of the Ni 8Ta phase and to continuous thickening of the corrosion product film consisting mostly of tantalum as cations. Ni 10Ta20P alloy consists of Ni 2Ta, Ni 3P, Ni 2P and NiP phases. Immersion of Ni10Ta20P alloy gives rise to initial increase in elemental phosphorus on the surface as a result of selective dissolution of nickel and selective oxidation of tantalum. The formation of elemental phosphorus with a high cathodic activity is responsible for the initial ennoblement of the open circuit potential and for the formation of the passive film in which tantalum is highly concentrated. The higher corrosion resistance of Ni10Ta20P alloy than Ni10Ta10P alloy is attributable to the formation of the Ni 2Ta phase with a higher tantalum content than the Ni 8Ta phase which is the readily corroded major intermetallic phase in the Ni10Ta10P alloy.

ChemInform Abstract: Effect of Phosphorus Addition on the Corrosion Behavior of Amorphous Fe‐8Cr‐P Alloys in 9 M H2SO4.

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

The effect of phosphorus addition on the corrosion behavior of amorphous Fe-8Cr-P alloys in 9M H 2SO 4

The corrosion resistance of amorphous Fe-8Cr-P alloys depends very strongly on the amount of phosphorus addition. The corrosion rates of crystalline Fe-8Cr-7P and Fe-Cr-13P alloys in 9 M H 2SO 4 solution at 30°C are extremely high in comparison with those of amorphous Fe-8Cr-P alloys with 16.5 at% or more phosphorus. An increase in the phosphorus content improves the corrosion resistance. The amorphous Fe-8Cr-16.5P and Fe-8Cr-18P alloys which are composed of very fine bcc phase dispersed in the amorphous matrix turn black after immersion for about 10 min, while the amorphous Fe-8Cr-20P alloy maintains the metallic luster after immersion for 168 h. Intense spectra of elements in the metallic state are observed in XPS analysis even though the specimen surface turns black. This metallic species found by XPS corresponds to the amorphous Fe-Cr-P phase which is not corroded. The thick corroded layer formed on Fe-8Cr-16.5P and Fe-8Cr-18P alloys seems to be the amorphous alloy phase after dissolution of the microcrystalline bcc Fe, the amorphous Fe-Cr-P phase being covered with a passive film. The amorphous Fe-8Cr-20P alloy does not show initial active dissolution, and the corrosion loss of this alloy is very small. Therefore, at least 20 at% addition of phosphorus to the Fe-8Cr alloy is necessary to form the completely amorphous structure and to provide the high corrosion resistance.

ChemInform Abstract: Effect of Phosphorus Addition on the Corrosion Behavior of Amorphous Ni‐30 Ta‐P Alloys in 12 M HCl.

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

The effect of phosphorus addition on the corrosion behavior of amorphous Ni-30Ta-P alloys in 12 M HCl

The addition of 3 at% phosphorus to amorphous Ni-30Ta alloy results in two orders of magnitude decrease in the corrosion rate in 12 M HCl at 30 °C. The amorphous Ni-30Ta-P alloys with 2 at% or more phosphorus were spontaneously passive. The open circuit potential of the phosphorus-free amorphous Ni-30Ta alloy decreases with time and becomes constant in the active region of nickel. By contrast, the open circuit potentials of the phosphorus-containing alloys increase with time of immersion. XPS analysis reveals that surface films on the Ni-30Ta alloys are composed exclusively of Ta 5+ ions as cations regardless of the presence of phosphorus. The film formed on the amorphous Ni-30Ta alloy is significantly thicker than that on the amorphous Ni-30Ta-5P alloy. The thick surface film on the Ni-30Ta alloy consists of a high concentration of OH − ions, while the passive film on the Ni-30Ta-5P alloy contains a high concentration of O 2− ions.

A novel effect of phosphorus addition on the activity of dispersed molybdenum-based catalysts in heavy oil hydrotreatment

This paper reports on the effect of phosphorous addition on the hydrodesulfurization activity of in situ formed dispersed Mo-Co-S catalysts evaluated for five different heavy oils. The hydrotreating experiments were carried out by using an autoclave of 300-mL capacity at a reaction temperature of 430{degrees} C. It was found that the sulfur removal goes through a maximum with increasing phosphorous addition for each heavy oil and that the amount of added phosphorous at the maximum is closely related to the vanadium content of the heavy oils. In addition, the increment of sulfur removal attainable by phosphorous addition was found to be larger for the heavy oils of higher vanadium content. These phenomena were reasonably explained by assuming the formation of oil-insoluble P-V compounds and their separation from the active Mo-Co-S catalyst phases and also by the poisoning effect of excess phosphorous.

Effects of phosphorus addition on reversible shape memory in liquid quenched Cu30at%Zn5at%Al alloys

Effects of phosphorus addition on reversible shape memory in liquid quenched Cu30at%Zn5at%Al alloys

Effect of Phosphorus Addition on Treatment Efficiency of a Lab Scale Anaerobic Filter, Treating Landfill Leachate

Abstract Sanitary landfill leachate has been a source of environmental concern due to its high organic strength and chemical diversity. A number of lab-scale and pilot scale studies have indicated that the anaerobic filter is highly competitive with other forms of biological treatment and has distinct economic advantages. While there have been a number of studies based on a general overall approach to leachate treatment by the anaerobic filter, limited information is available on the role played by essential nutrients like nitrogen and phosphorus in the biological treatment process. Laboratory studies were conducted at room temperature (22 °C) to study the effect of nutrient addition (specifically, phosphorus, the deficient constituent of leachate) on treatment efficiency of landfill leachate by the upflow anaerobic filter. Two anaerobic filters (0.975 metres x 0.15 metres diameter) were constructed using plexiglass pipes and packed with strips of corrugated fibre-glass sheets in four layers to form the filter bed. Leachate collected from a nearby landfill was applied at moderate organic loadings (1.8-4.0 kg COD/m3/day) to the two units maintaining a HRT of 0.987 days. Results indicate phosphorus addition may be made to organically diverse wastes such as landfill leachate with distinct advantages.

Phytoplankton Limitation by Phosphorus and Zooplankton Grazing in an Acidic Adirondack Lake

ABSTRACT Small (20 L) enclosures were used to study the effects of phosphorus addition and zooplankton removal on the phytoplankton of an acidic lake in the Adirondack Mountains of New York. Inspite of inorganic mechanisms which are capable of sequestering phosphate under acidic conditions the phytoplankton population bloomed after the addition of 80 μg L−1 of phosphate as KH2PO4. The response was measured by cell counts of the dominant phytoplankter, Chlamydomonas and changes in chlorophyll a concentration. About half the number of algal cells were present after the two week incubation when zooplankton were not removed, indicating that zooplankton herbivory can influence, but not totally control, the algal production.