Numerical calculation of a statically indeterminate frame by the finite element method

A numerical calculation of a statically indeterminate frame with high rigidity elements with the computer program STAB12. EXE using the finite element method is performed. An example of generating the source data for the program STAB12. EXE with subsequent processing of the results of the calculations is given. The features of checking the balance of nodes, rods and the frame as a whole based on the use of values taking into account the signs on the diagrams of torques, longitudinal and transverse forces are described. According to the results of calculations, the computer shows the frame in a deformed state.

Solid state NMR reveals a parallel in register architecture for an infectious recombinant prion

Two alternative architectures have been proposed for PrP Sc , the most notorious prion: a parallel in register β stack (PIRIBS) and a 4-rung β-solenoid (4RβS). We challenged these two models by measuring intermolecular 13 C- 13 C dipole-dipole couplings of 13 CO-labelled Phe residues in a fully infectious sample of recombinant bank vole PrP Sc (recBVPrP Sc ) using a PITHIRDS-CT solid state NMR (ssNMR) experiment. To our surprise, data strongly support a PIRIBS architecture. However, the mean distance measured (~6.5 Å) suggests that a minimum of two of the three Phe residues are not perfectly stacked at the canonical ~5 Å cross-β distance. Additional ssNMR experiments show some local conformational variability of the Phe residues within limits of a relatively high rigidity. The most parsimonious interpretation of our data is that recBVPrP Sc is arranged as a PIRIBS, although additional conformers with alternative architectures cannot be excluded, including a mixture of PIRIBS and 4RβS.

HIGH RIGIDITY AND VIBRATION ENDURANCE BAR FOR DEEP HOLES

Different constructions of bars are analyzed in the article, all of which are based on the idea of creating prestressed state in material. Improved construction of bar is proposed for equable spreading of elasticity zone along axis of boring bar.

Scientific substantiation of technology for manufacturing cylinder of TMZ-450D diesel engine

The analysis of complex technology for TMZ-450D diesel cylinder machining is presented. It is emphasized that a billet has a heterogeneous structure and that is why it is in need of ageing. It is proved that equipment rigidity in an acting engineering process is insufficient for the compensation of billet hereditary defects. New equipment with high rigidity is offered and introduced.

Outstanding Enhancement in the Axial Coordination Ability of the Highly Rigid Cofacial Cyclic Metalloporphyrin Dimer

<div>Copper- and nickel-porphyrin complexes show extremely weak axial coordination ability without any electron-withdrawing groups. Herein, we report axial ligation on Cu^II- and Ni^II-porphyrins in a highly rigid cofacial porphyrin dimer with a bidentate ligand, 1,4-diazabicyclo[2.2.2]octane (DABCO). To the best of our knowledge, this is the first report on the use of Cu^II- and Ni^II-porphyrins for coordination-induced guest binding of porphyrin-based host molecules without the help of other metal ions. The high rigidity of the dimer induces guest binding through the cooperative effect of weak axial ligation. The results showed that Cu^II- and Zn^II-complexes bind one DABCO molecule inside their cavities, whereas the Ni^II-complex binds two additional DABCO molecules outside to form a stable 6-coordinate paramagnetic Ni^II-complexes. <br></div>

Outstanding Enhancement in the Axial Coordination Ability of the Highly Rigid Cofacial Cyclic Metalloporphyrin Dimer

<div>Copper- and nickel-porphyrin complexes show extremely weak axial coordination ability without any electron-withdrawing groups. Herein, we report axial ligation on Cu^II- and Ni^II-porphyrins in a highly rigid cofacial porphyrin dimer with a bidentate ligand, 1,4-diazabicyclo[2.2.2]octane (DABCO). To the best of our knowledge, this is the first report on the use of Cu^II- and Ni^II-porphyrins for coordination-induced guest binding of porphyrin-based host molecules without the help of other metal ions. The high rigidity of the dimer induces guest binding through the cooperative effect of weak axial ligation. The results showed that Cu^II- and Zn^II-complexes bind one DABCO molecule inside their cavities, whereas the Ni^II-complex binds two additional DABCO molecules outside to form a stable 6-coordinate paramagnetic Ni^II-complexes. <br></div>

Bifurcation and Nonlinear Behavior Analysis of Dual-Directional Coupled Aerodynamic Bearing Systems

Dual-directional coupled aerodynamic bearing (DCAB) systems have received considerable attention over the past few years. These systems are primarily used to solve air lubrication problems in high-precision mechanisms and equipment that run at a high rotational speed and require high rigidity and precision. DCABs have the advantages of axial and radial thrust and provide high rigidity, dual-directional support, and high load-carrying capacity. In DCAB systems, the nonlinearity of the air film pressure and dynamic problems, such as critical speed, unbalanced air supply, or poor design, can cause the instability of the rotor-bearing system and phenomena such as nonperiodic or chaotic motion under certain parameters or conditions. Therefore, to investigate what conditions lead to nonperiodic phenomena and to avoid irregular vibration, the properties and performance of the DCAB system were explored in detail by using three numerical methods for verifying the accuracy of the numerical results. The rotor behavior was also studied by analyzing the spectral response, the bifurcation phenomenon, Poincaré maps, and the maximum Lyapunov exponent. The numerical results indicate that chaos occurs in the DCAB system for specific ranges of the rotor mass and bearing number. For example, when the rotor mass (mr) is 5.7 kg, chaotic regions where the maximum Lyapunov exponents are greater than 0 occur at bearing number ranges of 3.96–3.98 and 4.63–5.02. The coupling effect of the rotor mass and bearing number was also determined. This effect can provide an important guideline for avoiding an unstable state.