The Effect of Pre-Bond Contamination by Thermal Degradation and De-Icing Fluid on the Tensile Strength of Scarf Composite Bonded Joints

The synergistic effect of pre-bond contamination by thermal degradation and de-icing fluid on the tensile behavior of scarf composite bonded joints has been investigated experimentally. The contamination types considered are related to the repair process of composite aircraft structures. Three contamination scenarios have been considered: namely, thermal degradation (TD) and a combination of thermal degradation with two different levels of de-icing fluid (TD+DI1 and TD+DI2). DI2 is more severe than DI1. Contamination has been applied to one of the adherents while the other one has been intentionally left intact. Tension tests have been conducted on single-lap shear specimens. The experimental results were compared with the reference samples (REF) showing an increase in tensile strength for the TD specimens and a decrease in tensile strength for the TD+DI1 and TD+DI2 specimens. After the tension tests, the failure surfaces were evaluated to get a better insight of the failure mechanisms of the bondline and to assess the effect of contamination. The TD specimens presented an increased cohesive failure which is consistent with the increase of the failure load, while the combined contamination caused the failure of the composite adherents which again is consistent with the decrease of tensile strength of the scarf specimens.

ASSESSMENT OF THE COMBINED EFFECT OF HEAVY METALS AND POLYAROMATIC HYDROCARBONS ON THE CULTURAL PLANTS

The environmental contamination by heavy metals (HM) and polycyclic aromatic hydrocarbons (PAH) is often due to exposure to complex sources of industrial and agricultural activities. The aim of the work is to evaluate the combined effect of CuO and benzo(a)pyrene (BaP) on the state of spring barley plants. It was established that the soil combined pollution by CuO and BaP has a negative effect on all morphobiometric parameters of barley. The most sensitive indicators of combined contamination are the length of the roots, the mass of 1000 grains and the yield of barley.

Assessment of the combined effect of heavy metals and polyaromatic hydrocarbons on the cultural plants

The environmental contamination by heavy metals (HM) and polycyclic aromatic hydrocarbons (PAH) is often due to exposure to complex sources of industrial and agricultural activities. The aim of the work is to evaluate the combined effect of CuO and benzo(a)pyrene (BaP) on the state of spring barley plants. It was established that the soil combined pollution by CuO and BaP has a negative effect on all morphobiometric parameters of barley. The most sensitive indicators of combined contamination are the length of the roots, the mass of 1000 grains and the yield of barley.

Mycotoxicological study of feed corn grain (1998-2018)

For corn grain traded in the country's forage production sector over the past two decades, enzyme immunoassay showed persistent contamination with toxins of fusarium fungi, more often T-2 / HT-2 toxins, fumonisins, and more rarely with deoxynivalenol and zearalenone in quantities that pose risks of animal intoxication. The cases of superintensive accumulation of cyclopiazonic acid, citrinin, mycophenolic acid and ochratoxin A. were revealed. In 2016-2018 For maize grain from 4 subjects of the Central Federal District of the Russian Federation, a significant prevalence of T-2 / HT-2 toxins, deoxynivalenol and fumonisins was found with fluctuations in the frequency of occurrence of zearalenone over the years, diacetoxyscirpenol was detected in several samples from the Kursk and Voronezh regions. Contamination of grain with alternariol in 2016 and 2017 was mild both in frequency (5.3%) and accumulation levels (20–85 µg / kg), but in the collection of 2018, the proportion of samples containing this toxin was 40.7% with a content range of 25 295 µg / kg. The influence of soil and climatic factors on the nature of mycotoxin contamination of corn grain crops, the contribution of fungi belonging to dark-colored hyphomycetes and the prevailing variants of combined contamination with fusariotoxins are discussed.

MYCOTOXINS IN BEANS OF PEANUTS GROWN IN TAJIKISTAN

The article presents the results of an extensive mycotoxicological examination of 11 samples of peanut beans grown in two regions of the Republic of Tajikistan. The determination of 16 mycotoxins was carried out by indirect competitive enzyme-linked immunosorbent assay using commercial and certified research test systems. It has been established that for peanut beans in this area, a combined contamination by a group of sanitary-significant mycotoxins, including diacetoxyscirpenol, alternariol, ochratoxin A, PR-toxin and cyclopiazonic acid, is characteristic. The prospects of further research and the practical significance of the results are discussed.

Bioremediation of nitrate and Fe(ii) combined contamination in groundwater by heterotrophic denitrifying bacteria and microbial community analysis

The optimal condition range was determined for the simultaneous removal of nitrate and Fe(ii) in groundwater mediated by denitrifying Betaproteobacterial communities.