On the probability theory on MV algebras

 The paper contains a review of some results concerning probability theory on MV algebras (laws of large numbers, central limit theorem, martingale convergence theorem). Also some algebraic and methodical aspects are discussed.     

Impact of computer training courses on reduction of loneliness of older people in Finland and Slovenia

Previous research has shown loneliness as a threat for the quality of life of older people; therefore the goal of the intervention in a quasi-experimental study was to evaluate and discuss the self-reported level of loneliness of older people in Finland and Slovenia before and after a computer intervention. Intervention in a quasi-experimental study was conducted among 58 older participants at the baseline (M = 72.4 years) and 45 older participants at the follow-up research study (M = 72.9 years). Inferential statistics showed a significant difference in the reduction of loneliness between the countries, and a decreased level of loneliness of older people after completing the computer training course. Although older people experience many age-related problems which may reduce their interest in learning information and communication technology (ICT) skills, it is important that they are computer-proficient, because computer engagement can reduce the level of loneliness of older people and in this way has a positive effect on their quality of life.     

江汉油区出砂油井治理技术研究

经过40年的开发,江汉油区地层出砂越来越严重,致使作业维护井次逐年上升,严重影响了油井的正常生产。根据江汉油区出砂储层地质特征和出砂井生产现状,有针对性地开展出砂井井筒清砂和携砂举升采油技术研究或矿场试验,使出砂井治理收到了一定效果,缓解了地层出砂对油井生产的影响,为进一步开展出砂油井治理指明了主攻技术方向。     

Iterative performance improvement of fuzzy control systems for three tank systems

This paper suggests the performance improvement of fuzzy control systems (FCSs) for three tank systems using iterative feedback tuning (IFT). The stable design of Takagi–Sugeno–Kang fuzzy controllers is guaranteed by means of a stability theorem based on LaSalle’s global invariant set theorem formulated for a class of multi input-multi output (MIMO) nonlinear processes. An IFT algorithm characterized by setting the step size to guarantee the FCS stability is proposed. The theoretical approaches are applied in a case study that deals with the IFT-based stable design of fuzzy controllers dedicated to the level control of a cylindrical three tank system as a representative MIMO system. A set of experimental results for a laboratory setup illustrates the performance improvement.     

The investigation of metastable ζ-hcp phase in the Ag-rich f c c region of Ag-In alloys rapidly quenched from the melt

Stacking faults, which were detected in the Ag-In system, have been examined by transmission electron microscopy and electron diffraction. An enhanced concentration of stacking faults in splat cooled specimens as well as the formation of a metastable hexagonal phase in the f c c region of the alloy was observed. As far as we know this is the first case of the terminal solid solubility being reduced by rapid quenching. Terminal solid solubility is reduced because of the high concentration of structural defects introduced by quenching, e.g. dislocations and stacking faults, which serve as the nuclei for the transformation from the f c c to the h c p structure. Our measurements and calculations show that the stacking fault energy minimum is shifted to lower electron concentrations with respect to the stacking fault energy minimum corresponding to the equilibrium phase boundary for the f c c-h c p transformation. The new metastable phase boundary for this transformation was confirmed by X-ray examinations. We explain this earlier h c p phase appearance in rapid quenched specimens as the consequence of enhanced interaction of the Fermi surface and contracted Brillouin zone. The Brillouin zone contraction we attributed to quenched-in vacancies.     

Observation of a half-quantum-flux periodicity pattern in an rf SQUID with small critical currents

We have found experimentally that rf SQUID's working in a nonhysteretic mode with small critical currents give exactly at resonance and at very low rf bias a triangular pattern with a period equal to half of one elementary quantum of magnetic flux. We discuss a possible explanation of this peculiar result.     

Mechanical and fracture behavior of powder metalurgy processed Ti3Al-based alloys

This work considers structural and compression mechanical properties of three Ti₃Al-based alloys processed by powder metallurgy. Mechanically alloyed powders were compacted by hot-pressing to non-porous homogenous compacts. Prior to compression tests, all compacts were homogenized by a solution treatment at 1050°C (α + β region) for 1h, followed by water quenching. The compression tests were performed from room temperature to 500°C in vacuum at a strain rate of 2.4 × 10⁻³ s⁻¹. Detailed microstructural characterization has been evaluated by scanning electron microscopy (SEM), followed by electron dispersive spectroscopy (EDS) and X-ray diffraction analysis. Fracture topography was examined by SEM. The Ti₃Al-Nb alloy exhibits the highest ductility in the whole temperature range, whereas addition of Mo to Ti₃Al-Nb alloy yields the highest ultimate compression strength. A correlation between ductility and the fracture mode exists for all materials.