bluuebunny/crossref_metadata_2025_split huggingface dataset:
Struvite Precipitation and Phosphorous Removal from Urine Synthetic Solution: Reaction Kinetic Study
Authors: Shalaby Marwa Saied , El-Rafie Shadia 
Published: March 2015

Phosphorus, like oil, is a non-renewable resource that must be harvested from finite resources in the earth’s crust. An essential element for life, phosphorus is becoming increasingly scarce, contaminated, and difficult to extract. Struvite or magnesium ammonium phosphate (MgNH4PO4.6H2O) is a white, crystalline phosphate mineral that can be used as a bio-available fertilizer. The main objective of this research is to indicate the most important operating parameters affecting struvite precipitation by means of chemical reaction kinetics. The present study explores struvite precipitation by chemical method under different starting molar ratios, pH and SSR. It is shown that an increase of starting Mg: PO4: NH4 with respect to magnesium (1.6:1:1) strongly influences the growth rate of struvite and so the efficiency of the phosphate removal. This was attributed to the effect of magnesium on the struvite solubility product and on the reached supersaturation Super Saturation Ratio at optimum starting molar ratio and pH. It was also shown, by using chemical precipitation method that the determined Super Saturation Ratio (SSR) values of struvite, at 8, 8.5, 9, 9.5 and 10 are 1.314, 4.29, 8.89, 9.87 and 14.89 respectively are close to those presented in the literature for different origins of wastewater streams. The results show that SSR , pH, and starting molar ratio strongly influences the kinetics of precipitation and so phosphorous removal to reach 93% removal percent , 5.95 mg/lit as a minimum PO4 remained in solution, and 7.9 gm precipitated struvite from feed synthetic solution of 750 ml . The product was subjected to chemical analysis by means of EDIX-FTIR, SEM and XRD showing conformity with published literature. First-order kinetics was found to be sufficient to describe the rate data. The rates increased with increasing pH and so SSR and the apparent rate constants for the reaction were determined. © 2015 by Authors, Published by BCREC Group. This is an open access article under the CC BY-SA License (https://creativecommons.org/licenses/by-sa/4.0)
Mass Transfer and Chemical Reaction Approach of the Kinetics of the Acetylation of Gadung Flour using Glacial Acetic Acid
Authors: Kumoro Andri Cahyo , Amalia Rizka 
Published: March 2015

Acetylation is one of the common methods of modifying starch properties by introducing acetil (CH3CO) groups to starch molecules at low temperatures. While most acetylation is conducted using starch as anhidroglucose source and acetic anhydride or vinyl acetate as nucleophilic agents, this work employ reactants, namely flour and glacial acetic acid. The purpose of this work are to study the effect of pH reaction and GAA/GF mass ratio on the rate of acetylation reaction and to determine its rate constants. The acetylation of gadung flour with glacial acetic acid in the presence of sodium hydroxide as a homogenous catalyst was studied at ambient temperature with pH ranging from 8-10 and different mass ratio of acetic acid : gadung flour (1:3; 1:4; and 1:5). It was found that increasing pH, lead to increase the degree of substitution, while increasing GAA/GF mass ratio caused such decreases in the degree of substitution, due to the hydrolysis of the acetylated starch. The desired starch acetylation reaction is accompanied by undesirable hydrolysis reaction of the acetylated starch after 40-50 minutes reaction time. Investigation of kinetics of the reaction observed that the value of mass transfer rate constant (Kcs) is smaller than the surface reaction rate constant (k). Thus, it can be concluded that rate controlling step is mass transfer. © 2015 by Authors, Published by BCREC Group. This is an open access article under the CC BY-SA License (https://creativecommons.org/licenses/by-sa/4.0)
Selective Synthesis of Benzaldehydes by Hypochlorite Oxidation of Benzyl Alcohols under Phase Transfer Catalysis
Authors: Bijudas K. , Bashpa P. , Bibin V. P. , Nair Lakshmi , Priya A. P. , Aswathy M. , Krishnendu C. , Lisha P. 
Published: March 2015

The selective synthesis of benazaldehyde and substituted benzaldehydes from corresponding benzyl al-cohols has been carried out by using hypochlorite as an oxidant in organic medium under phase trans-fer catalysis. The reaction is highly selective since no traces of benzoic acid or substituted benzoic acids have been detected and the yield is found to be more than 90%. The products obtained were precipi-tated as 2,4-dinitrophenylhydrazone and the recrystallised products were characterized by melting point and by spectrophotometric techniques like infra red and UV-Visible analysis. © 2015 by Authors, Published by BCREC Group. This is an open access article under the CC BY-SA License (https://creativecommons.org/licenses/by-sa/4.0)
Preparation of TiO2-SiO2 using Rice Husk Ash as Silica Source and The Kinetics Study as Photocatalyst in Methyl Violet Decolorization
Authors: Fatimah Is , Said Ahmad , Hasanah Uun Ayil 
Published: March 2015

Preparation, characterization and utilization of TiO2-SiO2 as photocatalyst for methyl violet (MV) decolorization has been conducted. In this research, preparation of TiO2-SiO2 was developed based on natural renewable silica source; rice husk ash (RHA) via a sol-gel technique. The composite was formed by the dispersing of titanium isopropoxide as titania precursor into the gel of silica followed by aging, drying and calcination. The TiO2-SiO2 sample was characterized by powder X-ray diffraction (XRD), diffuse reflectance-UV Visible spectrophotometric analysis (DRUV-Vis), gas sorption analyzer and Scanning electron micrograph (SEM) before its utilization as photocatalyst in methyl violet photooxidation. As comparison to the physicochemical character study, the synthesis of TiO2-SiO2 by using tetraethyl ortosilicate (TEOS) was performed as a confirmation. Result showed that prepared TiO2-SiO2 has the character similar to TiO2-SiO2 as synthesized by TEOS precursor. The formation of crystalline titania in anatase and rutile phase was identified with increasing surface porosity data and the value of band gap energy which sufficiently contribute to a photocatalytic mechanism. The character data are in line with the kinetic data of methyl violet decolorization. From the compared photooxidation, photolysis, photocatalysis and adsorption process, it can be concluded that TiO2-SiO2 acts efficiently as a photocatalyst. © 2015 by Authors, Published by BCREC Group. This is an open access article under the CC BY-SA License (https://creativecommons.org/licenses/by-sa/4.0)
Stopped Flow Kinetics of MnII Catalysed Periodate Oxidation of 2, 3- dimethylaniline - Evaluation of Stability Constant of the Ternary Intermediate Complex
Authors: Kaushik Rajneesh D. , Agarwal Richa , Tyagi Priyanka , Singh Om , Singh Jaspal 
Published: March 2015

The formation of ternary intermediate unstable complex during the oxidation of aromatic amines by periodate ion catalysed by MnII has been proposed in case of some anilines. This paper is the first report on stopped-flow kinetic study and evaluation of stability constant of ternary complex forming in the MnII - catalysed periodate oxidation of 2, 3-dimethylaniline (D) in acetone-water medium. Stop-flow spectrophotometric method was used to study the ternary complex formation and to determine its stability constant. The stop-flow trace shows the reaction to occur in two steps. The first step, which is presumably the formation of ternary complex, is relatively fast while the second stage is relatively quite slow. The stability constant evaluated for D - MnII - IO4- ternary complex by determining equilibrium absorbance is (2.2 ± 1.0) × 105. Kinetics of ternary complex formation was defined by the rate law(A) under pseudo first order conditions.ln{[C2]eq / ( [C2]eq -[C2])} = kobs . t (A)where, kobs is the pseudo first order rate constant, [C2] is concentration of ternary complex at given time t, and [C2]eq is the equilibrium concentration of ternary complex.
Preparation, Characterization and NO-CO Redox Reaction Studies over Palladium and Rhodium Oxides Supported on Manganese Dioxide
Authors: Fal Desai M. S. , Kunkalekar R. K. , Salker A. V. 
Published: March 2015

The catalytic activity of PdO/MnO2 and Rh2O3/MnO2 is investigated for NO-CO redox reaction. Supported catalysts are prepared by wet impregnation method. Among the tested catalysts, PdO/MnO2 shows higher activity for this reaction. Active metal dispersion on MnO2 enhances the selectivity for N2 over N2O in this reaction. The XRD substantiate the formation of MnO2 monophasic phase. SEM images show the formation of elongated particles. TEM images indicate nano-size rod-like morphologies. An increase in the catalytic activity is observed on supported Pd and Rh oxides on MnO2. Temperature programed desorption studies with NO and CO are undertaken to investigate the catalytic surface studies. © 2015 by Authors, Published by BCREC Group. This is an open access article under the CC BY-SA License (https://creativecommons.org/licenses/by-sa/4.0)
Generation of Human Acute Lymphoblastic Leukemia Xenografts for Use in Oncology Drug Discovery
Authors: Holmfeldt Linda , Mullighan Charles G. 
Published: March 2015

AbstractThe establishment of reproducible mouse models of acute lymphoblastic leukemia (ALL) is necessary to provide in vivo therapeutic test systems that recapitulate human ALL, and for amplification of limited amounts of primary tumor material. A popular assay is the primary xenograft model that utilizes immunocompromised mice. The protocol includes injection of primary patient tumor specimens into mice with subsequent serial passaging of the tumors by retransplants of cells harvested from the mouse bone marrow and spleen. The tumors generated are then used for genomic profiling, ex vivo compound testing, mechanistic studies and retransplantation. Detailed in this unit are procedures for the establishment and maintenance of primary ALL xenograft panels for use in basic research and translational studies. © 2015 by John Wiley & Sons, Inc.
Isolation and Culture of Spinal Cord Motor Neurons
Authors: Klausmeyer Alice , Stern D. , Wiese S. 
Published: March 2015

AbstractIsolated spinal motoneurons are a powerful tool for studying basic mechanisms of neurite growth and survival. Since motoneurons are a minor population of developing spinal cord cells, they need to be purified and enriched to separate them from non‐neuronal cells. Therefore, the particular feature of embryonic motoneurons to express the low affinity neurotrophin receptor p75NTR is used to separate the motoneurons from other contaminating cells. Two ways are described to isolate embryonic motoneurons: the basic protocol taking advantage of the ability of p75NTR to bind lectin, and an alternative method using an antibody against p75NTR for a panning procedure. These protocols comprise suggestions for the cultivation of the isolated motoneurons for experiments regarding neural outgrowth and survival as well as instruction for the preparation of proteins of the cells. © 2015 by John Wiley & Sons, Inc.
Adhesive Micropatterns to Study Intermediate Filament Function in Nuclear Positioning
Authors: Dupin Isabelle , Elric Julien , Etienne‐Manneville Sandrine 
Published: March 2015

AbstractThe nucleus is generally found near the cell center; however its position can vary in response to extracellular or intracellular signals, leading to a polarized intracellular organization. Nuclear movement is mediated by the cytoskeleton and its associated motors. While the role of actin and microtubule cytoskeletons in nuclear positioning has been assessed in various systems, the contribution of intermediate filaments is less established due in part to the lack of tools to study intermediate filament functions. The methods described here use micropatterned substrates to impose reproducible cell shape and nucleus position. Intermediate filament organization can be perturbed using gene downregulation or upregulation; intermediate filaments can also be visualized using fluorescent intermediate filament proteins. This protocol is valuable for characterizing the role of intermediate filaments in a variety of live or fixed adherent cells. © 2015 by John Wiley & Sons, Inc.
An upper mantle seismic discontinuity beneath the Galápagos Archipelago and its implications for studies of the lithosphere‐asthenosphere boundary
Authors: Byrnes Joseph S. , Hooft Emilie E. E. , Toomey Douglas R. , Villagómez Darwin R. , Geist Dennis J. , Solomon Sean C. 
Published: March 2015

AbstractAn upper mantle seismic discontinuity (the Gutenberg or G discontinuity), at which shear wave velocity decreases with depth, has been mapped from S‐to‐p conversions in radial receiver functions recorded across the Galápagos Archipelago. The mean depth of the discontinuity is 91 ± 8 km beneath the southeastern archipelago and 72 ± 5 km beneath surrounding regions. The discontinuity appears deeper beneath the portion of the Nazca plate that we infer passed over the Galápagos mantle plume than elsewhere in the region. We equate the depth of the G discontinuity to the maximum depth extent of anhydrous melting, which forms an overlying layer of dehydrated and depleted mantle. We attribute areas of shallow discontinuity depth to the formation of the dehydrated layer near the Galápagos Spreading Center and areas of greater discontinuity depth to its modification over a mantle plume with an excess temperature of 115 ± 30°C. The G discontinuity lies within a high‐seismic‐velocity anomaly that we conclude forms by partial dehydration and a gradual but steady increase in seismic velocity with decreasing depth after upwelling mantle first encounters the solidus for volatile‐bearing mantle material. At the depth of the solidus for anhydrous mantle material, removal of remaining water creates a sharp decrease in velocity with depth; this discontinuity may also mark a site of melt accumulation. Results from seismic imaging, the compositions of Galápagos lavas, and rare‐earth‐element concentrations across the archipelago require that mantle upwelling and partial melting occur over a broad region within the dehydrated and depleted layer. We conclude that the G discontinuity beneath the archipelago does not mark the boundary between rigid lithosphere and convecting asthenosphere.
Recent accelerated warming of the continental shelf off New Jersey: Observations from the CMVOleander expendable bathythermograph line
Authors: Forsyth Jacob Samuel Tse , Andres Magdalena , Gawarkiewicz Glen G. 
Published: March 2015

AbstractExpendable bathythermographs (XBTs) have been launched along a repeat track from New Jersey to Bermuda from the CMV Oleander through the NOAA/NEFSC Ship of Opportunity Program about 14 times per year since 1977. The XBT temperatures on the Middle Atlantic Bight shelf are binned with 10 km horizontal and 5 m vertical resolution to produce monthly, seasonally, and annually averaged cross‐shelf temperature sections. The depth‐averaged shelf temperature, Ts, calculated from annually averaged sections that are spatially averaged across the shelf, increases at 0.026 ± 0.001°C yr−1 from 1977 to 2013, with the recent trend substantially larger than the overall 37 year trend (0.11 ± 0.02°C yr−1 since 2002). The Oleander temperature sections suggest that the recent acceleration in warming on the shelf is not confined to the surface, but occurs throughout the water column with some contribution from interactions between the shelf and the adjacent Slope Sea reflected in cross‐shelf motions of the shelfbreak front. The local warming on the shelf cannot explain the region's amplified rate of sea level rise relative to the global mean. Additionally, Ts exhibits significant interannual variability with the warmest anomalies increasing in intensity over the 37 year record even as the cold anomalies remain relatively uniform throughout the record. Ts anomalies are not correlated with annually averaged coastal sea level anomalies at zero lag. However, positive correlation is found between 2 year lagged Ts anomalies and coastal sea level anomalies, suggesting that the region's sea level anomalies may serve as a predictor of shelf temperature.
Response of Arctic Ocean stratification to changing river runoff in a column model
Authors: Nummelin Aleksi , Li Camille , Smedsrud Lars H. 
Published: March 2015

AbstractA one‐dimensional model of the atmosphere‐ice‐ocean column is used to study the effects of changing river runoff to the Arctic Ocean. River runoff is the largest contributor of freshwater to the Arctic and is expected to increase as the hydrological cycle accelerates due to global warming. The column model simulates the stratification of the Arctic Ocean reasonably well, capturing important features such as the fresh surface layer, the salty cold halocline, and the temperature maximum within the Atlantic Water layer. The model is run for 500 years with prescribed boundary conditions to reach steady state solutions. Increasing river runoff is found to strengthen the stratification and to produce a fresher and shallower surface mixed layer with warming (up to ∼1°C for a doubling of present‐day runoff) in the Atlantic Water layer below. An important consequence is that the effect of the larger vertical temperature gradient is able to balance that of the stronger stratification and yield a close to constant vertical heat flux toward the surface. As a result, the sea ice response is small, showing only slight increase (up to ∼15 cm for a doubling of present‐day runoff) in annual mean ice thickness. Limitations of the study include the idealized nature of the column model and uncertainties in the background vertical mixing within the Arctic Ocean.
Assessment of the upper‐ocean mixed layer parameterizations using a large eddy simulation model
Authors: Furuichi Naoki , Hibiya Toshiyuki 
Published: March 2015

AbstractA large eddy simulation (LES) of the upper ocean mixed layer processes in the winter northwestern Pacific is carried out and compared with concurrent microstructure measurements. We find that dissipation rates of turbulent kinetic energy (ε) and temperature variance from LES agree well with field observations in the areas where the Ozmidov length scale, calculated from the modeled ε and buoyancy frequency, exceeds the grid size of LES. It is also found that, even though the Ozmidov length scale is less than the grid size of LES, model estimates of the vertical turbulent heat flux near the base of the mixed layer are very similar to observed values, suggesting that this LES model reproduces the intensity of entrainment well. This enables us to use the results from LES to assess the turbulence closure models of Mellor and Yamada [1982, MY] and Nakanishi and Niino [2009, NN] for several forcing scenarios consisting of strong winds, surface heating, and surface cooling. It is found that NN performs better than MY in reproducing the results from LES for each forcing scenario, particularly when the turbulent length scale is adjusted to be more restricted by density stratification.
Correlating carbon and oxygen isotope events in early to middle Miocene shallow marine carbonates in the Mediterranean region using orbitally tuned chemostratigraphy and lithostratigraphy
Authors: Auer Gerald , Piller Werner E. , Reuter Markus , Harzhauser Mathias 
Published: March 2015

AbstractDuring the Miocene prominent oxygen isotope events (Mi‐events) reflect major changes in glaciation, while carbonate isotope maxima (CM‐events) reflect changes in organic carbon burial, particularly during the Monterey carbon isotope excursion. However, despite their importance to the global climate history they have never been recorded in shallow marine carbonate successions. The Decontra section on the Maiella Platform (central Apennines, Italy), however, allows to resolve them for the first time in such a setting during the early to middle Miocene. The present study improves the stratigraphic resolution of parts of the Decontra section via orbital tuning of high‐resolution gamma ray (GR) and magnetic susceptibility data to the 405 kyr eccentricity metronome. The tuning allows, within the established biostratigraphic, sequence stratigraphic, and isotope stratigraphic frameworks, a precise correlation of the Decontra section with pelagic records of the Mediterranean region, as well as the global paleoclimatic record and the global sea level curve. Spectral series analyses of GR data further indicate that the 405 kyr orbital cycle is particularly well preserved during the Monterey Event. Since GR is a direct proxy for authigenic uranium precipitation during increased burial of organic carbon in the Decontra section, it follows the same long‐term orbital pacing as observed in the carbon isotope records. The 405 kyr GR beat is thus correlated with the carbon isotope maxima observed during the Monterey Event. Finally, the Mi‐events can now be recognized in the δ18O record and coincide with plankton‐rich, siliceous, or phosphatic horizons in the lithology of the section.
A hybrid pore‐scale and continuum‐scale model for solute diffusion, reaction, and biofilm development in porous media
Authors: Tang Youneng , Valocchi Albert J. , Werth Charles J. 
Published: March 2015

AbstractIt is a challenge to upscale solute transport in porous media for multispecies bio‐kinetic reactions because of incomplete mixing within the elementary volume and because biofilm growth can change porosity and affect pore‐scale flow and diffusion. To address this challenge, we present a hybrid model that couples pore‐scale subdomains to continuum‐scale subdomains. While the pore‐scale subdomains involving significant biofilm growth and reaction are simulated using pore‐scale equations, the other subdomains are simulated using continuum‐scale equations to save computational time. The pore‐scale and continuum‐scale subdomains are coupled using a mortar method to ensure continuity of solute concentration and flux at the interfaces. We present results for a simplified two‐dimensional system, neglect advection, and use dual Monod kinetics for solute utilization and biofilm growth. The results based on the hybrid model are consistent with the results based on a pore‐scale model for three test cases that cover a wide range of Damköhler (Da = reaction rate/diffusion rate) numbers for both homogeneous (spatially periodic) and heterogeneous pore structures. We compare results from the hybrid method with an upscaled continuum model and show that the latter is valid only for cases of small Damköhler numbers, consistent with other results reported in the literature.
Altitude and solar activity dependence of 1967–2005 thermospheric density trends derived from orbital drag
Authors: Emmert J. T. 
Published: March 2015

AbstractWe examine 1967–2005 thermospheric mass density trends (as well as 1967–2013 trends) derived from satellite orbit data, as a function of altitude, solar flux, and geomagnetic activity. At 400 km altitude, the estimated 1967–2005 trend is −2.0 ± 0.5% per decade. The estimated trends become increasingly negative with increasing height between 250 and 575 km, suggesting an exospheric temperature trend of −1 to −2 K per decade, which is much smaller than temperature trends that have been inferred from ground‐based incoherent scatter radar measurements. The orbit‐derived trend height profiles are in good agreement with model simulations of the enhanced cooling that results from increasing concentration of CO2 in the mesosphere and lower thermosphere. In contrast to earlier results, the solar flux dependence of the estimated trends is weak, relative to the trend uncertainty. There is some indication that the trends may be stronger during very low geomagnetic activity conditions. Estimation of the solar flux and geomagnetic activity dependence of the trends is complicated by monotonic decreases in these drivers over the past four solar minima together with the CO2 increase, all of which drive interminima decreases in density.