The effect of factors on the process chemical modification tar with formaldehyde using a sulfuric acid as catalyst has been studied. By experimental results, adequate statistical-mathematical (ESM) model developed. Based this model, optimal values have identified, bringing about penetration value and softening point modified tars. Data predicted basis ESM were compared empirical evidence tars p...

BACKGROUND This multicenter, observational study was conducted in three European countries (Germany, Switzerland, and the United Kingdom) to determine the exposure of adult cigarette smokers and nonsmokers to selected cigarette smoke constituents: 1,3-butadiene, 2-naphthylamine, 4-aminobiphenyl, 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK), acrolein, benzene, carbon monoxide, nicotine, ...

We estimate the profitability of producing biochar from crop residue (corn stover) for two scenarios. The first employs slow pyrolysis to generate biochar and pyrolysis gas and has the advantage of high yields of char (as much as 40 wt-%) but the disadvantage of producing a relatively low-value energy product (pyrolysis gas of modest heating value). The second scenario employs fast pyrolysis to...

The pyrolysis of TVSb has been investigated in a flow tube reactor using Dz and He carrier gases. For TVSb alone, the most likely pyrolysis reaction involves an Sbcentered reductive elimination pathway. A less likely possibility is pyrolysis via homolysis of the Sb-C bonds, yielding vinyl radicals. Unfortunately, examination of the organic byproducts in both He and D, yields insufficient inform...

The effect of corn stover lignin structure alteration caused by white-rot fungi pretreatment on the pyrolysis kinetics was studied by FTIR and TG/DTA. Results showed that biopretreatment had a remarkable effect on lignin pyrolysis. Biopretreatment can decrease the activation energy and increase the pre-exponential factor in the initial stage of pyrolysis, which makes it possible to start the li...

This study demonstrates the ability of tar isolated from environmental tobacco smoke (ETS) to nick DNA in mammalian cells. Solutions of ETS tar behave similarly to aqueous solutions of cigarette tar from mainstream smoke. Both solutions contain the tar semiquinone radical, and this radical associates with the DNA in viable rat alveolar macrophages. Solutions of tar from ETS cause single-strand ...

Analytical pyrolysis is a technique currently used for investigating structural features of complex macromolecular materials. However, pitfalls appear to be widespread in pyrolysis studies of humic substances, and serious limitations can be experienced during the analytical procedure due to thermal reactions and configuration of the pyrolysis units and chromatographic systems. Pyrolysis present...

The ability of aqueous extracts of cigarette tar to nick DNA was investigated using viable mammalian cells. Tar extracts contain a radical with a stable electron spin resonance (ESR) signal at g = 2.0036 characteristic of a semiquinone. The association of the tar component that carries the ESR signal with DNA was demonstrated using viable rat alveolar macrophages. The formation of single-strand...