FEATURES OF IRON COATING ELECTRO-GALVANIC METHOD

The paper analyzes the technological process of electro-electroplating-mechanical coating in comparison with a similar process without mechanical impact on the formed coating.

Development of technology of creams using hydrocolloids

The article presents a scientific study of the functional and technological properties of hydrocolloids, namely thickeners of polysaccharide nature, which are used as thickeners and stabilizers in dessert products. According to the monitoring of literature sources and the experience of manufacturers, the most commonly used thickeners of polysaccharide nature are carrageenan, locust bean gum, xanthan gum, pectin, starch, etc. However, each of these polysaccharides has both positive and negative sides, more polysaccharides are able to form dense gels, but with a high synergistic effect. Thickeners, such as k-carrageenan, low-esterified pectins, can form gels only in the presence of Са2+. There are also polysaccharides that form gels only at low temperatures and are not stable during external factors (temperature of sale and storage, mechanical impact, etc.). Therefore, the study was conducted on the combination of polysaccharides in order to obtain creams with an airy gel-like structure. It has been determined, that it is expedient to use the combination "xanthan gum 0.75 % – locust bean gum 0.5 %" to obtain cream

Coupling in silico and ex vivo porcine model for the evaluation of biomechanical impact of TEVAR

The study couples the experimental and the computational approaches in an integrated in silico and ex vivo biomechanical analysis of porcine aorta. The aim of the presented work is to evaluate the mechanical impact of TEVAR on aortic structure.

Effect of External Impacts on the Structure and Martensitic Transformation of Rapidly Quenched TiNiCu Alloys

TiNi-TiCu quasibinary system alloys with a high Cu content produced by rapid quenching from liquid state in the form of thin amorphous ribbons exhibit pronounced shape memory effect after crystallization and are promising materials for miniaturized and fast operating devices. There is currently no complete clarity of the mechanisms of structure formation during crystallization from the amorphous state that determine the structure-sensitive properties of these alloys. This work deals with the effect of the initial amorphous state structure and crystallization method of the alloys on their structure and phase transformations. To this end the alloy containing 30 at.% Cu was subjected to thermal and mechanical impact in the amorphous state and crystallized using isothermal or electropulse treatment. We show that after all types of treatment in the amorphous state the structure of the alloy remains almost completely amorphous but the characteristic temperatures and enthalpy of crystallization become slightly lower. Isothermal crystallization of alloy specimens produces a submicrocrystalline structure with an average grain size in the 0.4–1.0 μm range whereas electropulse crystallization generates a bimorphic structure consisting of large 4–6 μm grains and 2–3 μm high columnar crystals in the vicinity of the surface. The grains have nanosized plate-like and subgrain structures. The largest grains are observed in thermally activated samples, meanwhile, mechanical impact in the amorphous state leads to the formation of equiaxed finer grains with a less defective subgrain structure and to the shift of the temperature range of the martensitic transformation toward lower temperatures.

Dynamics of pneumatic drive of devices for udder massage of animals

The paper presents the results of theoretical developments on the deformation of flexible shells of the executive bodies of the means of stripping, the assessment of their mechanical impact on the udder of the heifer and first-calf, the dynamics of the pneumatic drive of the executive bodies. The design and technological parameters of the devices for milking first-calf heifers and massaging the udder of heifers are justified, the set and duration of technological operations for animal milking and the economic efficiency of their implementation are determined.

Application of high frequency mechanical impact treatment to improve the fatigue strength of corroding welded joints

This study deals with the fatigue strength of high-frequency mechanical impact (HFMI)-treated unprotected structural details made of mild steel S355 considering the influence of corrosive environmental conditions. The investigations are carried out on butt welded specimens with sheet thickness t = 15 mm and on transverse non-load-carrying attachment specimens with sheet thickness t = 25 mm. Two different methods were applied for the simulation of marine corrosive environment in the laboratory. Specimens first were deposited in a salt spray chamber and then tested subsequently dry at laboratory-air conditions considering the influence of corrosion on the crack initiation. Alternatively, and to cover the effects of corrosion on the crack growth, artificial seawater was used for pre-corrosion, and after a defined timespan, fatigue tests were performed simultaneously with the specimen resting in the corrosive medium. The corrosion fatigue tests were performed in as-welded and HFMI-treated conditions at a stress ratio R = 0.1 under axial tensile and 4-point bending cyclic loading. The test results are evaluated to determine the characteristic fatigue strengths for fixed slopes m = 3 and m = 5 according to IIW recommendations for the as-welded and for the HFMI-treated condition respectively. The results of the experimental investigations based on the nominal stress approach show that the fatigue strength of both specimen types could be significantly increased by the application of HFMI treatment compared to the corresponding specimens in the as-welded condition even if exposed to the investigated corrosive conditions. The comparison with the design proposals of IIW shows that for HFMI-treated butt welds, no reduction of the FAT class due to corrosion is required and the recommended FAT class is still valid. The results for the HFMI-treated transverse attachments are slightly below the design curve recommended by IIW and a proposal to consider corrosion is derived for this case. Additional numerical investigations by applying the effective notch stress (ENS) approach are performed to determine notch stress curves. It was found that for the corroded specimens in the as-welded condition, the FAT class according to IIW could not be reached and adjustments of the existing rules are necessary to consider corrosion effects. However, it can be concluded that the effective notch fatigue resistance recommended by IIW is still applicable in the case of corroded HFMI-treated structural details.