Determination of the ultimate biodegradation of plastics materials in an aqueous system under anoxic (denitrifying) conditions. Method by measurement of pressure increase

2020 ◽  
Keyword(s):  
Aqueous System ◽  
Pressure Increase

scholarly journals A Terbium Sensitized Luminescence Method for the Assay of Flubiprofen in Pharmaceutical Formulations

2014 ◽  
Vol 19 (1) ◽  
pp. 54
Author(s):  
Salma M.Z. Al-Kindy ◽  
Arwa Al-Ghazali ◽  
Fakhr Eldin O. Suliman ◽  
Haidar A.J. Al-Lawati
Keyword(s):  
Limit Of Detection ◽  
Tap Water ◽  
Pharmaceutical Formulations ◽  
Aqueous System ◽  
Tween 20 ◽  
Luminescence Method ◽  
Time Resolved ◽  
Relative Standard ◽  
Excellent Reproducibility

A sensitive time-resolved luminescence method for the determination of flubiprofen (FLP) in methanol and in aqueous solution is described. The method is based on the luminescence sensitization of terbium (Tb3+ ) by the formation of a ternary complex with FLP in the presence of 4,7 diphenyl 1,10 phenanthroline (DPP) as co-ligand, and Tween-20 as surfactant. The signal for Tb-FLP-DPP was monitored at λex  = 285 nm and λem  = 552 nm. Optimum conditions for the formation of the complex in an aqueous system were TRIS buffer, pH 8.0, DPP (2.5Å~10−7  M), Tween-20 (0.30%) and 4Å~10-5  mol L-1  of Tb3+  which allowed the determination of 20–1000 ng mL-1  of FLP with a limit of detection (LOD) of 10 ng mL-1 . The relative standard deviations of the method ranged between 0.6 and 1.4% indicating excellent reproducibility of the method. The proposed method was successfully applied for the assays of FLP in pharmaceutical formulations and spiked tap water samples with average recoveries of 87% – 95%. 

The Determination of Friction Coefficient between Parallel Wires in Stay Cables

2013 ◽  
Vol 351-352 ◽  
pp. 250-253 ◽  
Author(s):  
Hong Li
Keyword(s):  
Friction Coefficient ◽  
High Strength Steel ◽  
Steel Wire ◽  
High Strength ◽  
Pressure Increase ◽  
Positive Pressure ◽  
Stay Cables ◽  
Steel Wires ◽  
Bending Stresses

To measure and determine the friction coefficients of steel wires accurately is one of the prerequisite for analysing the local bending stresses in staycables. Three test schemes to simulate the real working state of the steel wire, the test value and its variation trend shows that the friction coefficient of high-strength steel wires decreases with the pressure increase, and then becomes stable when the positive pressure is too large.

Application of l-cysteine capped core–shell CdTe/ZnS nanoparticles as a fluorescence probe for cephalexin

2014 ◽  
Vol 6 (8) ◽  
pp. 2715-2721 ◽  
Author(s):  
Li Li ◽  
Qiaolin Zhang ◽  
Yaping Ding ◽  
Xiaoyong Cai ◽  
Shuqing Gu ◽  
...  
Keyword(s):  
Fluorescence Intensity ◽  
Fluorescence Probe ◽  
Aqueous System ◽  
Core Shell ◽  
Zns Nanoparticles ◽  
Good Probe

l-Cysteine capped CdTe/ZnS NPs were prepared in an aqueous system and the fluorescence intensity was significantly reduced when the concentration of cephalexin increased, which proves a good probe for determination of cephalexin in pharmaceutical fields.

scholarly journals PAN-Immobilized PVC-NPOE Membrane for Environmentally Friendly Sensing of Cd(II) Ions

2017 ◽  
Vol 17 (1) ◽  
pp. 1 ◽  
Author(s):  
Moersilah Moersilah ◽  
Dwi Siswanta ◽  
Roto Roto ◽  
Mudasir Mudasir
Keyword(s):  
Water Samples ◽  
Limit Of Detection ◽  
Internal Standard ◽  
Environmentally Friendly ◽  
Aqueous System ◽  
Sensor Membrane ◽  
Poly Vinyl Chloride ◽  
Nitrophenyl Octyl Ether ◽  
Membrane Changes

A simple, cheap and environmentally friendly analytical method of Cd(II) in the aqueous system has been developed by immobilization of 1-(2-pyridilazo)-2-naphtol (PAN) in poly vinyl chloride (PVC) matrix and nitrophenyl octyl ether (NPOE) as a plasticizer. Upon contact with Cd(II) in solution, the color of sensor membrane changes from dark yellow to dark red, which is due to the formation of Cd(II)–PAN complex. The best sensing results were obtained at pH 8.0 and λmax 558 nm. The dimension of the proposed sensor membrane was 0.8 cm x 2 cm with a thickness of 0.05 mm, the volume of sample was 2 mL with the Cd(II) concentration range of  0 – 1.2 ppm. The limit of detection of the method was found to be 0.432 + 0.104 ppm, which was reversible. The proposed methods have been applied in the determination of Cd(II) in water samples after addition of internal standard.

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