Prediction of the Mechanical Properties of P91 Steel by Means of Magneto-acoustic Emission and Acoustic Birefringence

The paper describes an application of non-destructive volumetric magnetic and ultrasonic techniques for evaluation of the selected mechanical parameter variations of P91 steel having direct influence on its suitability for further use in critical components used in power plants. Two different types of deformation processes were carried out. First, a series of the P91 steel specimens was subjected to creep and second, one to plastic deformation in order to achieve the material with an increasing strain level up to 10%. Subsequently, non-destructive and destructive tests were performed. Magnetic methods based on measurements of magnetoacoustic emission and magnetic hysteresis loop changes as well as the ultrasonic method based on acoustic birefringence measurements, were applied. Finally, the static tensile tests were carried out in order to evaluate the mechanical parameters. It is shown that some relationships between the selected parameters coming from the non-destructive and destructive tests may be formulated.     

Polymer Microtips Fabricated at the Extremity of Photonic Crystal Fibers

In this paper, a simple method of manufacturing micrometer-sized polymer elements （microtips） at the extremities of the photonic crystal fibers （PCFs）, which are replacing standard optical fibers in many applications due to their unique properties, is presented. The method of microtips fabrication is based on the phenomena of photopolymerization, which is successfully used by the first time, to be best of our knowledge, to manufacture microtip at PCF. The three component photopolymerizable formulation consists of photo-initiating system and multifunctional triacrylate. The photopolymerization is carried out by green laser with the microtip growth controlled by the light exposure parameters （i.e. power and time）. Results of mic：rotip fabrication on standard fiber （SMF-28e＋） and large mode area PCF （LMA-10） are provided. Theinfluence of the initial process parameters on the final microtip characteristics （i.e., length, diameter and profile） is discussed. The potential applications of such polymer microtips are near-field scanning optical microscopy, coupling light sources with fibers and sensing.     

Radioluminescence and photoluminescence of hafnia-based Eu-doped phosphors

Crystal structures of hafnia are discussed and it is shown that addition of about 7 at.% of Lu to the HfO₂ host lattice enforces the mixed composition to crystallize in cubic structure even at room temperature. Without Lu HfO₂ crystallizes in monoclinic structure. Luminescence and luminescence excitation spectra of Hf_0.93Lu_0.07O_1.965 are presented and discussed for powders prepared at different temperatures (600–1000 °C) and with different content of Eu. It is shown that decay of the 595.4 nm luminescence is longer (2.5 ms) than the 610 nm (1.6 ms). Radioluminescence efficiency of the cubic Hf_0.93Lu_0.07O_1.965 is low and does not exceed 10% of the commercial Gd₂O₂S:Eu.     

Electromotive force measurements in liquid Ag-In-Pd lead-free alloys

Emf technique was employed to determine indium activities in the liquid Ag-In-Pd alloys using galvanic cells with yttria-stabilised-zirconia as solid electrolyte according to the scheme： kanthal/rhenium, Ag-In-Pd, In2O3 ｜ YSZ ｜ Ni, NiO, Pt. Composition and temperature measurement ranges were limited, because of very steep liquidus surface; 35 compositions for Xpd up to 0.3 were investigated and at temperatures from near-liquidus up to 1700 K. High temperature experiments required special moly furnace to be constructed with unique automatic gas supply system for fumace winding protective atmosphere. Emf readings were taken and recorded by automatic data acquisition system. Linear dependence of emf on temperature was observed for all compositions investigated, and results were approximated by straight line equa- tions. Then In activities were calculated using well-known relations and taking into account correction for thermoelectric power between kanthal and platinum. Results are to be used along with other existing data to perform assessment of the ternary system under accord.     

Effect of isosorbide dinitrate on pulmonary venous compliance

Irreversible poor pulmonary venous compliance (PV comp) could worsened natural course of patients (pts) with high pulmonary capillary wedge pressure especially pts with mitral stenosis. Nitrates (isosorbide dinitrate-ISDN) possessing venous dilating action could increase PV comp in most of pts. The main aim of that study was to assess hemodynamic effects of ISDN, in pts with MS, with special emphasis on PV com changes. PV comp was estimated according to Hirakawa equation (dV/dp = 0.4*k2*SV/(v-d) in 35 pts with MS, during preoperative right heart catheterisation with VYGON 5155-180 thermodilution catheters during rest and effort in supine position (25W). The same protocol was performed after Iso-Mack sprawy 3.75 mg. According to the PV comp response to ISDN, pts were divided in two groups: good responders (I)-15% and higher increase in PV comp and poor responders (II). ISDN increased PV comp in the whole group according to the response to ISDN, there were significant differences in stroke volume index (SVI) and heart rate (HR). In the group of good responders mean right atrial pressure (RA), mean pulmonary artery pressure (PAP), mean pulmonary wedge pressure (PWP) decreased significantly with simultaneous slight not significant decrease in SVI and not significant increase of HR. In the group of poor responders SVI decreased significantly by about 20% with significant increase of HR. In conclusion significant decrease in pulmonary pressures (PAP, PWP) in pts with good response to ISDN are secondary to the increase of PV comp, while among poor responders the same effects are due to diminished flow secondary to the decrease of the systemic venous return.     

Brain Glucose Transporters: Role in Pathogenesis and Potential Targets for the Treatment of Alzheimer’s Disease

The most common cause of dementia, especially in elderly people, is Alzheimer’s disease (AD), with aging as its main risk factor. AD is a multifactorial neurodegenerative disease. There are several factors increasing the risk of AD development. One of the main features of Alzheimer’s disease is impairment of brain energy. Hypometabolism caused by decreased glucose uptake is observed in specific areas of the AD-affected brain. Therefore, glucose hypometabolism and energy deficit are hallmarks of AD. There are several hypotheses that explain the role of glucose hypometabolism in AD, but data available on this subject are poor. Reduced transport of glucose into neurons may be related to decreased expression of glucose transporters in neurons and glia. On the other hand, glucose transporters may play a role as potential targets for the treatment of AD. Compounds such as antidiabetic drugs, agonists of SGLT1, insulin, siRNA and liposomes are suggested as therapeutics. Nevertheless, the suggested targets of therapy need further investigations.     

Mechanical and Infrared Thermography Analysis of Shape Memory Polyurethane

Multifunctional new material—polyurethane shape memory polymer (PU-SMP)—was subjected to tension carried out at room temperature at various strain rates. The influence of effects of thermomechanical couplings on the SMP mechanical properties was studied, based on the sample temperature changes, measured by a fast and sensitive infrared camera. It was found that the polymer deformation process strongly depends on the strain rate applied. The initial reversible strain is accompanied by a small drop in temperature, called thermoelastic effect. Its maximal value is related to the SMP yield point and increases upon increase of the strain rate. At higher strains, the stress and temperature significantly increase, caused by reorientation of the polymer molecular chains, followed by the stress drop and its subsequent increase accompanying the sample rupture. The higher strain rate, the higher stress, and temperature changes were obtained, since the deformation process was more dynamic and has occurred in almost adiabatic conditions. The constitutive model of SMP valid in finite strain regime was developed. In the proposed approach, SMP is described as a two-phase material composed of hyperelastic rubbery phase and elastic-viscoplastic glassy phase, while the volume content of phases is specified by the current temperature.     

Effects of Brain Size on Adult Neurogenesis in Shrews

Shrews are small animals found in many different habitats. Like other mammals, adult neurogenesis occurs in the subventricular zone of the lateral ventricle (SVZ) and the dentate gyrus (DG) of the hippocampal formation. We asked whether the number of new generated cells in shrews depends on their brain size. We examined Crocidura russula and Neomys fodiens, weighing 10–22 g, and Crocidura olivieri and Suncus murinus that weigh three times more. We found that the density of proliferated cells in the SVZ was approximately at the same level in all species. These cells migrated from the SVZ through the rostral migratory stream to the olfactory bulb (OB). In this pathway, a low level of neurogenesis occurred in C. olivieri compared to three other species of shrews. In the DG, the rate of adult neurogenesis was regulated differently. Specifically, the lowest density of newly generated neurons was observed in C. russula, which had a substantial number of new neurons in the OB compared with C. olivieri. We suggest that the number of newly generated neurons in an adult shrew’s brain is independent of the brain size, and molecular mechanisms of neurogenesis appeared to be different in two neurogenic structures.     

Grinding of coal in the presence of vapours of organic compounds

The effect exerted by the sorption of vapour of several chemical compounds on the crushing of bituminous coal was investigated. Air-dry samples of a low-rank coal (82.7 wt%C) a coking coal (87.0 wt%C) and a high-rank coal (91.7 wt%C) were saturated with methanol, ammonia and benzene vapour for 100 h, crushed in a ball-mill, and subjected to sieve analysis. Sorption of methanol causes a marked increase of the crushability of all coals tested. Coal crushability increasing with increase of rank. The results have been interpreted according to the polymeric model of coal structure.