Utilization of α-olefins obtained by pyrolysis of waste high density polyethylene to synthesize α-olefin-succinic-anhydride based cold flow improvers

A new route of utilization of α-olefin rich hydrocarbon fractions obtained by waste polymer pyrolysis was investigated. α-olefin-succinic-anhydride intermediate-based pour point depressant additives for diesel fuel were synthesized, in which reactions needed α-olefins were obtained by pyrolysis of waste high-density polyethylene (HDPE). Fraction of α-olefins was produced by the de-polymerization of plastic waste in a tube reactor at 500℃ in the absence of catalysts and air. C_17~22 range of mixtures of olefins and paraffins were separated for synthesis and then, these hydrocarbons were reacted with maleic-anhydride (MA) for formation of α-olefin-succinic-anhydride intermediates. The olefin-rich hydrocarbon fraction contained approximately 60% of olefins, including 90%~95% α-olefins. Other intermediates were produced in the same way by using commercial C₂₀ α-olefin instead of C_17~22 olefin mixture. The two different experimental intermediates with number average molecular weights of 1850g/mol and 1760g/mol were reacted with different alcohols: 1-butanol, 1-hexanol, 1-octanol, i-butanol, and c-hexanol to produce their ester derivatives. The synthesized ten experimental pour point depressants were added in different concentrations to conventional diesel fuel, which had no other additive content before. The structure and efficiency of experimental additives were followed by different standardized and non-standardized methods. Results showed that the experimental additives on the basis of the product of waste pyrolysis were able to decrease not only the pour but also the cloud point and cold filter plugging point (CFPP) of diesel fuel, whose effects could be observed even if the concentration of additives was low. Furthermore, all additives had anti-wear and anti-friction effects in diesel fuel.     

New Approach to the Calculation of Relative Sensitivity Factors in Inductively Coupled Plasma Mass Spectrometry

The relative sensitivity factors (RSFs) of 68 elements in inductively coupled plasma mass spectrometry were determined. The ionization process in an inductively coupled plasma was found to be only approximately described by the Saha–Eggert equation. A relationship between the RSFs and the absolute electronegativities of atoms was found. This factor has the strongest effect on the accuracy of the calculations of RSFs for chemically active elements. The average relative systematic error of the calculations of RSFs taking into account absolute electronegativity was reduced to 0.30.     

Determination of Neodymium and Ytterbium by Isotope Dilution Laser Mass Spectrometry

The experimental conditions for minimizing errors in the laser mass spectrometric (LMS) analysis of isotopic ratios for Nd and Yb were found, and the optimum isotope pairs for determining these elements with the use of isotope dilution (ID) were chosen. The precision and accuracy of LMS data, which are characterized by relative random errors (RSD) and relative systematic errors (), can be improved using ID. The values for Nd or Yb were no higher than RSD = 2.9% and = 0.024 or RSD = 5% and = 0.097, respectively.     

An alternating direction scheme on a nonuniform mesh for reaction-diffusion parabolic problems

In this paper we develop a numerical method for two-dimensionaltime-dependent reaction-diffusion problems. This method, whichcan immediately be generalized to higher dimensions, is shownto be uniformly convergent with respect to the diffusion problems.This method, which can immediately be generalized to higherdimensions, is shown to be uniformly convergent with respectto the diffusion parameter.     

Errors in isotope ratios measured on a laser mass spectrometer with photographic recording

The random and systematic measurement errors were determined for tin isotope ratios measured by laser mass spectrometry with photographic recording. The analytical isotope signals were treated by the Hull equation using the widths of mass-spectrometric lines. This method significantly reduced the systematic measurement error in the isotope ratios and extended the working range of signal intensities (0.1 <T< 10). Within this range, the relative standard deviation (s _r ) of the measured isotope ratios wass _r < 0.15, and the relative systematic error was S < 0.15. For isotope lines with close signal intensities in the region of normal blackening of the photographic emulsion, the valuess _r = 0.04-0.08 and δ = 0.01 were obtained. A discrimination effect was revealed for isotopes with large masses 120, 122, and 124 amu, which increased δ to 0.21     

New policy in the accreditation of testing and calibration laboratories in Russia

 The structure and activities of a new accreditation body called the Russian Union of Measurement Accreditation Systems (RUMAS) are briefly described.