Selective Functionalization of Microstructured Surfaces by Laser‐Assisted Particle Transfer

Microcavity arrays represent millions of different reaction compartments to screen, for example, molecular interactions, exogenous factors for cells or enzymatic activity. A novel method is presented to selectively synthesize different compounds in arrays of microcavities with up to 1 000 000 cavities per cm². In this approach, polymer microparticles with embedded pre‐activated monomers are selectively transferred into microcavities with laser radiation. After particle patterning, heating of the particle matrix simultaneously leads to diffusion and coupling of the monomers inside each microcavity separately. This method exhibits flexibility, not only in the choice of compounds, but also in the choice of particle matrix material, which determines the chemical reaction environment. The laser‐assisted selective functionalization of microcavities can be easily combined with the intensively growing number of laser applications for patterning of molecules and cells, which is useful for the development of novel biological assays.     

Rheological Properties and Similarity Conditions in Simulating the Upsetting of a Titanium Alloy VT20 Billet: II. Simulation of the Upsetting of Experimental Samples and Virtual Billets

The compression of cylindrical samples 15 mm in diameter and virtual billets 150 mm in diameter made of a VT20 alloy and having various ratios of the initial sizes is simulated under similarity conditions. The influence of a nonuniform distribution of the average stress and the cumulative strain, as the factors that determine the microstructural heterogeneity, is discussed.     

Combined hardening of alloy Ti-6Al sheet workpieces during reversible hydrogen alloying

The effect of the initial hydrogen concentration, warm rolling, and vacuum annealing conditions on the formation of the phase composition, structure, and mechanical properties of rolled sheet workpieces made of a Ti-6Al α alloy is studied. When the initial hydrogen concentration increases to C _Hⁱⁿⁱ = 0.3–0.9%, the grain size decreases and the phase composition of the alloy is complicated. In the grain size range 27–5 μm, the yield strength of the alloy obeys the Hall-Petch relation with the lattice friction stress σ _i = 662 MPa. When the initial hydrogen concentration increases, the grain-boundary hardening intensity and the yield strength increase. At an average α grain size of 5 μm, the yield strength increases from 770 MPa in the alloy with C _Hⁱⁿⁱ = 0.004% to 970 MPa in the alloy with C _Hⁱⁿⁱ = 0.7%. The maximum yield strength (σ_y = 1064 MPa) is obtained for the alloy with C _Hⁱⁿⁱ= 0.5% after vacuum annealing at 650°C. The conditions and contributions of solid-solution hardening, grain-boundary hardening, precipitation hardening induced by the formation of the α₂ phase, and strain hardening to the total hardening of the alloy are considered.     

Thermal transformations of 4-<Emphasis Type="Italic">tert</Emphasis>-butylbiphenyl

The thermal stability of 4-tert-butylbiphenyl was studied in the range of 703–763 K. The competition of the cracking and isomerization reactions of alkyl substituents on the aromatic ring of the reactant and its products has been revealed. The kinetic characteristics of the complex of transformations occurring in the system have been determined. Recommendations are provided regarding the conditions for the determination of the critical parameters of 4-tert-butylbiphenyl and for the processing and use of compounds with a tert-butyl moiety in the molecule.     

Experience in introducing automation equipment for electric drives and industrial systems into the educational process

The use of industrial facilities for educational purposes is considered. Original solutions implemented in the design and construction of laboratory installations at the Department of Electrical Drives and the Automation of Industrial Installations of the Ural State Technical University Ural Polytechnical Institute (USTU-UPI) are described.     

Control of flight parameters of a quadrotor vehicle moving over a given trajectory

The problem of control of an autonomous unmanned aerial vehicle with vertical takeoff and landing, which moves over a trajectory specified in the coordinate space, is considered. A method of constructing a system of automatic control of quadrotor vehicle takeoff and flight is proposed. Analytical relations for control actions on four engines that ensure vehicle motion over a prescribed trajectory with desired values of altitude and velocity are derived.     

Low-frequency pulsations of melt during lost foam casting process: Part I

An investigation into the process of the appearance of low-frequency pulsations of liquid metal in a mold is carried out on the basis of a mathematical model of kinetics of mold filling during the lost foam casting process (LFCP). The mold filling is shown to occur with a delay, when a gas space arises between the material of the lost pattern and liquid metal, which gets a mechanical impulse, causing fluctuations of its level in the riser and pressure in the gas space. The natural frequency of fluctuations in the gas space is shown to decrease (at first abruptly and then slowly) as the mold is filled by metal. At the same time, this depends weakly on the gas permeability of the mold, slightly increasing and then stabilizing as the feed speed of the liquid metal into the mold increases and decreases as the rarefaction in a flask increases.     

Device Determining Depth and Space Orientation of Controlled Pneumatic Puncher in Soil

The gradient method for detection of rotating magnetic field emitter placed on the pneumatic puncher is considered. The results of in-situ tests are given.     

Interval and Twin Arithmetics

The problem of finding inner and outer estimations of the range of values of a real function is considered. An overview of interval arithmetics being used for improvement of outer estimations is given. The twin arithmetic is introduced for simultaneous inner and outer estimations and directed twin arithmetic is proposed as generalization of the directed interval arithmetic.     

Cancer metastases to the cervical lymph nodes in an unknown primary location of the tumor

Out of 120 patients hospitalized with the diagnosis of metastases to the cervical lymph nodes and unknown primary location of the tumor, tumors were detected in 29 and lymphosarcoma in 10. In 24 (82.7%) patients the tumor was located in the upper respiratory tract and gastrointestinal tract. Malignant tumors of the naso- and stomatopharynx and vestibular part of the larynx most often metastasize into the lymph nodes. Radiotherapy was administered to all 81 patients with metastases and unknown location of the primary tumor and to 10 patients with lymphosarcoma of the cervical lymph nodes. The protocol of radiotherapy took account of the site of the metastases and probable primary tumor. A radical course provides cure in 15% of cases, as shown by follow-up of at least 2 years.