Electrical conductivity of graft tissues of pome crops is an indicator of accretion quality

The article presents experimental data on the electrical conductivity of tissues of grafted apple and pear crops to identify patterns of electrical conductivity in qualitative accretion of grafting components at early stages. For the fastest implementation of the varieties and clonal rootstocks obtained by breeding, it is important to select stable scion-stock combinations. The main task remains to detect incompatibility of the components of grafts at an early age, since its manifestation in adult plants causes significant damage to production. The studies were carried out in different years on winter and summer grafts. Patterns of the electrical conductivity dynamics are established: with qualitative fusion of grafting components, a monotonous increase in electrical conductivity is observed when the values of electrical conductivity change between the 1st and 14th day within 80 μS. In case of poor quality growth of grafting components, values of electric conductivity of tissues practically do not change (±5-10 μS). In rotting tissue (in visually unchanged tissues) values of electrical conductivity of all components of grafting in the period from the 8th to the 18th day after grafting are sharply increased by 100 mS, which is connected with water ion exchange disorder in tissues. When reproduction by budding in its initial period, in compatible combinations, the drop in tissue conductivity values at the grafting site was no more than 20 μS compared to the indications on the rootstock above the grafting site. On the 16th day of measurements, the readings of the electrical conductivity tissues at the grafting site and on the reverse side were practically unchanged (± 5 μS) — this indicate a gradual repair of the grafting tissues.

Highly stretchable and sensitive piezoresistive carbon nanotube/elastomeric triisocyanate-crosslinked polytetrahydrofuran nanocomposites

A family of CNT/ETC-PTHF nanocomposites exhibiting high stretchability and high sensitivity to mechanical stimuli was developed. The electrical conductivity change of 15 wt% CNT/ETC-PTHF nanocomposites decreased by 7.3% and 1291 times under 1% and 500% tensile strain, respectively.

Analysis of Ageing Precipitation Behavior of an Aluminum Alloy

The characterization of Al-Cu-Mg-Ag alloy with high Cu:Mg in the process of one-step ageing at the different temperatures has been studied by hardness, electrical conductivity test combining with transmission electron microscopy (TEM) and differential scanning calorimetry (DSC). The results show that one endothermic and three exothermic reactions are involved in the curve of DSC experiment for a sample quenched from 520°C. Four samples were aged at the different temperatures greater or less than the peak temperatures of the four reactions. Hardness and electrical conductivity change slowly with ageing time at the low temperature and change fast at the high temperature. GP zones at {100} ɑ planes are the main precipitates in the microstructure of the sample aged at 80°C. Ω and θ phases dominant the microstructure of the samples aged at 170°C, 230°C and 280°C. In addition, the size of precipitates increases fast when the sample aged at higher temperatures.