Approximated Uncertainty Propagation of Correlated Independent Variables Using the Ordinary Least Squares Estimator.

For chemical measurements, calibration is typically conducted by regression analysis. In many cases, generalized approaches are required to account for a complex-structured variance-covariance matrix of (in)dependent variables. However, in the particular case of highly correlated independent variables, the ordinary least squares (OLS) method can play a rational role with an approximated propagation of uncertainties of the correlated independent variables into that of a calibrated value for a particular case in which standard deviation of fit residuals are close to the uncertainties along the ordinate of calibration data.

Development of a Novel Leak-Free Constant-Pressure Cylinder for Certified Reference Materials of Liquid Hydrocarbon Mixtures.

Liquid hydrocarbon mixtures such as liquefied petroleum gas and liquefied natural gas are becoming integral parts of the world's energy system. Certified reference materials (CRMs) of liquid hydrocarbon mixtures are necessary to allow assessment of the accuracy and traceability of the compositions of such materials. A piston-type constant-pressure cylinder (PCPC) comprising chambers for a pressurizing gas (helium) and liquid (hydrocarbons) separated by a piston can be used to develop accurate and traceable liquid hydrocarbon mixture CRMs.

Preparation of Pt-Ru@ polypyrrole-MWNT catalysts by gamma-irradiation and chemical reduction and their adsorption capacity for CO.

With the objective to prepare electrocatalysts with high efficiency, the Pt-Ru@PPy-MWNT catalysts were prepared by different approaches. First, the polypyrrole (PPy) as anchoring materials was coated on the surface of multi walled carbon nanotubes (MWNT) by in situ polymerization. Subsequently, Pt-Ru nanoparticles were deposited onto PPy-MWNT composite by different methods like the reduction of metal ions by gamma-irradiation and chemical reduction using formaldehyde as reducing agent assisted with stirring of magnetic bar, and assisted with microwave irradiation, and assisted with ultrasonic irradiation, in order to prepare electrocatalyst for fuel cell.

Fabrication of chemiluminescence sensor based on conducting polymer@SiO2/Nafion composite film.

Tris(2,2'-bipyridyl)ruthenium (II) (Ru(bpy)2+) electrogerated chemiluminescence (ECL) sensor was fabricated by immobilization of Ru(bpy)2+ complex on conducting polymer@SiO2/Nafion composite film on surface of glassy carbon electrode. The conducting polymer@SiO2 nanocomposites were prepared by coating polyaniline (PANI), polypyrrole (PPy), and polythiophene (PTh) on the surface of the SiO2 sphere. The conducting polymer@SiO2 nanocomposite was characterized by scanning electron microscopy (SEM), Transmission electron microscopy (TEM), and atomic force microscopy (AFM).

Horseradish peroxidase immobilized on poly(thiophene-2-aminophenol-3-thiopheneacetic acid) film electrode with Au nanoparticle-fabrication and evaluation as hydrogen peroxide sensor.

Enzyme immobilized electrode was fabricated by two methods. In one of the methods, gold-nanoparticles (Au-NPs) prepared by gamma-irradiation were loaded into the copolymer film and horseradish peroxidase (HRP) was immobilized into the Au-NPs loaded copolymer film through physical entrapment. In the other method, the Au-NPs was prepared by electrochemical reduction of Au ions on the surface of poly(Th-AP-TAA) and HRP was immobilized into the Au-NPs.

Fabrication of functional poly(thiophene) electrode for biosensors.

Three-type polymer electrodes such as poly(Th), poly(Th-AP) and poly(Th-AP-TAA) were fabricated, respectively, by electro-oxidative polymerization of thiophene (Th), mixture of Th and 2-aminophenol (AP), and mixture of Th, AP and 3-thiopheneacetic acid (TAA) on the surface of indium tin oxide (ITO) glass by cyclic voltammetry (CV). The polymer electrodes were electrodeposited by cycling the potential between -1.0 and +2.