Mechanical state assessment using lamb wave technique in static tensile tests

The paper deals with the investigation of Lamb wave ultrasonic technique for damage (or mechanical state) evaluation of AA7068T3 specimens in the course of tensile testing. Two piezoelectric transducers (PZT), one of which is used as an actuator and the other as sensor, were adhesively bonded on the specimen surface using epoxy. Two frequencies of testing signals (60 kHz and 350 kHz) were used. The set of static tensile tests were performed. The recorded signals were processed to calculate the informative parameters in order to evaluate the changes in stress-strain state of the specimens and their microstructure

Stress and Strain State Analysis of Defective Pipeline Portion

The paper presents computer simulation results of the pipeline having defects in a welded joint. Autodesk Inventor software is used for simulation of the stress and strain state of the pipeline. Places of the possible failure and stress concentrators are predicted on the defective portion of the pipeline

Contribution of some immunological and metabolic factors to formation of piglets’ post-vaccination immunity

The role and responsibility of natural resistance factors, protein and lipid metabolism in the formation of piglets post-vaccination immunity against circovirus is researched. Blood was taken for tests before and on the 15th, 40th and 70th day after the vaccination. The sampled blood was analyzed to determine immunological and biochemical parameters. It was revealed that before vaccination, 31.46% of the studied samples have a positive reaction in ELISA; their number increases to 67.80–71.16% on the 40th and 70th days after vaccination.In the blood of piglets, especially on the 40th and 70th day after the vaccination, the total count of leukocytes, monocytes and lymphocytes increases by 1.21; 2.28 times and 1.48 times, but neutrophils reduced by 1.74 times along with the phagocytic properties activation. The anabolic directivity of protein metabolism is defined by the synthesis of globulin proteins. At the same time albumin-synthesizing activity in a liver decreased and “cytolysis reaction” of hepatocytes was detected. In the lipid profile of piglets’ blood, the content of LDL‑cholesterol increased by 1.44 times, while that of triglycerides decreased by 2.64 times. X‑ray spectral analysis revealed the correlation between the formation of post-vaccination immunity and two factors: the factor of the principal component (PC) 1, which is predominantly associated with indicators of natural resistance, and PC2, which is associated with metabolism indicators. The research results show that in order to increase the efficiency of formation of post-vaccination immunity in piglets, it is necessary to combine vaccination with hepatoprotective drugs