Electrochemistry at anthracene crystal/aqueous nitrite, nitrate solution interface

1988 ◽  
Vol 92 (9) ◽  
pp. 2506-2511
Author(s):  
Baldwin Leong ◽  
Martin Pope ◽  
Joseph Steigman
Keyword(s):  
Nitrate Solution ◽  
Solution Interface ◽  
Anthracene Crystal ◽  
Nitrite Nitrate

scholarly journals MEASUREMENT OF DISSOLVED INORGANIC NUTRIENT IN EUPHOTIC ZONE THE BANTEN BAY

2010 ◽  
Vol 9 (2) ◽  
pp. 217-225
Author(s):  
Alianto Alianto ◽  
Enan M. Adiwilaga ◽  
Ario Damar ◽  
Enang Harris
Keyword(s):  
Chemical Composition ◽  
Nitrate Solution ◽  
Euphotic Zone ◽  
Inorganic Nutrient ◽  
Low Concentration ◽  
Intensity Measurements ◽  
Yellow Solution ◽  
Nitrite Nitrate

At a few this last years, measurement concentration of dissolved inorganic nutrient is has rapidlyed grow by using various methods. But method anything applied must based on at formation of indicator end of measurement amonia, nitrite, nitrate, orthophosphate and silicate. At measurement of amonia its indicator is formation of blue indophenol, nitrite formation of pink azo, nitrate formation of yellow colored solution, orthophosphate formation of blue molybdenum, and silicate based on formation of yellows silicomolibdate. The intensity of color that is highly dependent on the concentration of each element. Measurement of amonia blue indophenol intensity perfected concentration in the range 0.206-0.396 mg/L. Measurement nitrite the formation of a pink azo easy imperfect because its low concentration. Intensity measurements nitrate solution yellow perfect concentration in the range 0.128-0.989 mg/L. Measurement of imperfect blue molybdenum intensity orthophosphate because its low concentration. While measuring the formation silicate of yellow silicomolibdate  perfect concentration on the range 10.573-26.470 mg/L. As a whole from result of measurement is obtained chemical composition of dissolved inorganic nutrient in euphotic zone the Banten bay is more predominated by silicate 97.27%, nitrate 1.84%, amonia 0.49%, orthophosphate 0.20%, and nitrite 0.18%.   Keywords: blue indophenol, pink azo, yellow solution, blue molybdenum, yellow silicomolibdate

Template mediated crystal engineering

1994 ◽  
Vol 52 ◽  
pp. 480-481
Author(s):  
Brigid R. Heywood ◽  
S. Champ
Keyword(s):  
Crystal Engineering ◽  
Electrostatic Interactions ◽  
Alkyl Chain ◽  
Crystallographic Axis ◽  
Two Dimensional ◽  
Engineering Process ◽  
Solution Interface ◽  
Extensive Program ◽  
Geometric Homology ◽  
Long Alkyl Chain

Recent work on the crystallisation of inorganic crystals under compressed monomolecular surfactant films has shown that two dimensional templates can be used to promote the oriented nucleation of solids. When a suitable long alkyl chain surfactant is cast on the crystallisation media a monodispersied population of crystals forms exclusively at the monolayer/solution interface. Each crystal is aligned with a specific crystallographic axis perpendicular to the plane of the monolayer suggesting that nucleation is facilitated by recognition events between the nascent inorganic solid and the organic template.For example, monolayers of the long alkyl chain surfactant, stearic acid will promote the oriented nucleation of the calcium carbonate polymorph, calcite, on the (100) face, whereas compressed monolayers of n-eicosyl sulphate will induce calcite nucleation on the (001) face, (Figure 1 & 2). An extensive program of research has confirmed the general principle that molecular recognition events at the interface (including electrostatic interactions, geometric homology, stereochemical complementarity) can be used to promote the crystal engineering process.

Effects of resuspension of eastern oyster Crassostrea virginica biodeposits on phytoplankton community structure

2020 ◽  
Vol 640 ◽  
pp. 79-105
Author(s):  
ET Porter ◽  
E Robins ◽  
S Davis ◽  
R Lacouture ◽  
JC Cornwell
Keyword(s):  
Water Quality ◽  
Community Structure ◽  
Crassostrea Virginica ◽  
Skeletonema Costatum ◽  
Eastern Oyster ◽  
Energy Dissipation Rate ◽  
Negative Effects ◽  
Cell Densities ◽  
Sediment Bottom ◽  
Nitrite Nitrate

Anthropogenic disturbances in the Chesapeake Bay (USA) have depleted eastern oyster Crassostrea virginica abundance and altered the estuary’s environment and water quality. Efforts to rehabilitate oyster populations are underway; however, the effect of oyster biodeposits on water quality and plankton community structure are not clear. In July 2017, we used 6 shear turbulence resuspension mesocosms (STURMs) to determine differences in plankton composition with and without the daily addition of oyster biodeposits to a muddy sediment bottom. STURM systems had a volume-weighted root mean square turbulent velocity of 1.08 cm s-1, energy dissipation rate of ~0.08 cm2 s-3, and bottom shear stress of ~0.36-0.51 Pa during mixing-on periods during 4 wk of tidal resuspension. Phytoplankton increased their chlorophyll a content in their cells in response to low light in tanks with biodeposits. The diatom Skeletonema costatum bloomed and had significantly longer chains in tanks without biodeposits. These tanks also had significantly lower concentrations of total suspended solids, zooplankton carbon, and nitrite +nitrate, and higher phytoplankton carbon concentrations. Results suggest that the absence of biodeposit resuspension initiates nitrogen uptake for diatom reproduction, increasing the cell densities of S. costatum. The low abundance of the zooplankton population in non-biodeposit tanks suggests an inability of zooplankton to graze on S. costatum and negative effects of S. costatum on zooplankton. A high abundance of the copepod Acartia tonsa in biodeposit tanks may have reduced S. costatum chain length. Oyster biodeposit addition and resuspension efficiently transferred phytoplankton carbon to zooplankton carbon, thus supporting the food web in the estuary.

Enterovirus Concentration Using Automated Hollow Fiber Ultrafiltration

1982 ◽  
Vol 14 (4-5) ◽  
pp. 257-272 ◽  
Author(s):  
G Belfort ◽  
A Paluszek ◽  
L S Sturman
Keyword(s):  
Drinking Water ◽  
Hollow Fiber ◽  
Enhanced Recovery ◽  
Tap Water ◽  
Membrane Surface ◽  
Creeping Flow ◽  
Hollow Fibers ◽  
Virus Concentration ◽  
Concentration Technique ◽  
Solution Interface

The Automated Hollow Fiber Ultrafiltration (AHFU) method is proposed here as a simple, efficient and rapid virus concentration technique from tap and drinking water sources. The results reported here extend the testing of the AHFU method to include two Picornaviruses [Poliovirus 2 (vaccine) and Echovirus 1] and Reovirus 3. Their respective mean virus recoveries from between 3 and 100 l of tap water is 88 ± 26, 79 ± 60, and 104 ± 48%. Various approaches including membrane surface modification, changes in backwash hydrodynamics, modification of the feed and backwash composition, and the use of S35-methionine labelled Poliovirus 2, are used to study the recovery of sorbed Poliovirus 2 from the hollow fiber/solution interface. An increase in the backwash pH to between 9.5 and 10.5 significantly improved Poliovirus 2 recovery. This, together with the labelled experiments, indicates that the virus-membrane interactions are probably electrostatic in nature. Convective polarization during filtration probably brings the virus close enough to the surface for these interactions to occur since virus losses were not detected for a non-permeation recycle experiment. Because very low Reynold's numbers are used, the flow is in the creeping-flow-regime for both filtration and backwashing (axial and radial). Unless significantly higher Reynolds could be used, enhanced recovery due to purely hydrodynamic forces is unlikely. High Reynold's numbers, of course, are limited by the pressure constraints of the hollow fibers.

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