Makromolekulární hydrogely: heterogenní struktura a deformačn chování

Title: Polymer hydrogels: heterogeneous structure and deformation behavior Author: Evgeny Karpushkin Department: Department of Macromolecular Physics, Faculty of Mathematics and Physics, Charles University in Prague Supervisor: Miroslava Dušková-Smrčková Ing. Dr., Institute of Macromolecular Chemistry AS CR, Heyrovského náměstí 2, 162 06 Prague 6 Abstract: Model series of crosslinked poly(2-hydroxyethyl methacrylate) hydrogels differing in morphology were prepared by polymerization-induced phase separation. Morphology, swelling and dynamic mechanical properties in broad frequency range of the model gels were tested. The vitrification of gels was found sensitive to microstructure of polymer network and to solvent content and to polymer-solvent interaction, but not to the macroscopic morphology of the gel. The low-frequency mechanical response was found sensitive to both polymer network properties and hydrogel morphology. Lightly crosslinked hydrogels showed relatively high mechanical losses in the rubbery plateau region, due to physical association of chains. Fused-particles type hydrogels revealed a weak secondary relaxation at low frequency, ascribed to motion of the dangling particles aggregates. These aggregates, elastically inactive, along with inhomogeneous stress field arisen in porous material, were...Název práce: Makromolekulární hydrogely: heterogenní struktura a deformační chování Autor: Evgeny Karpushkin Katedra / Ústav: Katedra makromolekulární fyziky MFF UK Vedoucí disertační práce: Miroslava Dušková-Smrčková Ing. Dr., Ústav makromolekulární chemie AV ČR, Heyrovského náměstí 2, 162 06 Praha 6 Abstrakt: Morfologie, botnání a dynamicko-mechanické vlastnosti syntetických hydrogelů o různé morfologické struktuře byly studovány s cílem nalézt vztah mezi strukturou sítě, architekturou porozity a mechanickou odezvou. Modelová řada syntetických hydrogelů byla připravena radikálovou polymerizací 2-hydroxethylmethakrylátu se síťovadlem za přítomnosti vody a jiných aditiv tak, aby se v průběhu síťování uplatnil jev fázové separace a tím došlo k vytvoření modelových gelů o různé morfologii. Z mechanické odezvy rovnovážně zbotnalých vzorků vyplývá, že frekvenční průběh hlavního relaxačního přechodu nezávisí na uspořádání a typu porů a do malé koncentrace síťovadla (1 mol% na monomery) ani na struktuře sítě. Odezva v nízkém oboru frekvencí (<10-2) závisí značně jak na struktuře polymerní sítě, tak na morfologické stavbě zbotnalého hydrogelu. Mírně sesíťované gely vykazovaly vyšší mechanické ztráty v oblasti kaučukového plata, což je připsáno přeskupování asociovaných hydrofobních domén polymerních řetězců. U...Katedra makromolekulární fyzikyDepartment of Macromolecular PhysicsFaculty of Mathematics and PhysicsMatematicko-fyzikální fakult

Psychological and physiological characteristics of criminals and victims of crimes of personal freedom based on Russian criminal cases

A person’s personality is a carrier of individual, unique signs and traits that depend on its nature and are formed during life experience, including during the commission of crimes. We studied 320 criminal cases of violations of personal freedom (kidnapping, human trafficking, the use of their slave labor, etc.), as well as an analysis of the scientific literature that made it possible to substantiate the characteristics of criminals and their victims. As a result of the study, criminals and their victims were classified into groups. The features of these groups were characterized. The study of the personal properties of criminals and victims is necessary for all crimes of personal freedom, regardless of the commission country, and allows you to properly organize an investigation, put forward standard versions, build work to find traces and means of crime, thereby exposing the criminal

Design optimization of heating plates for hydraulic presses

The paper describes the problem of design optimization of heating plates for hydraulic presses used for heat treatment of rubber, plastics, and metals. The problem involves finding the number and capacity of heaters or the heating steam pressure, the appropriate configuration of slots for heaters or steam supply channels to ensure the required heating rate of the plate to the operating temperature, and the permissible level of non-uniformity of the temperature field of its working surface. The adequacy of the mathematical description of the thermal process in heating plates for presses is confirmed by comparing the results of the solution of mathematical models with the data of the industrial experiments. The results of solving the problem for induction heating plates and resistive heating plates are presented

Analytical description of the time-over-threshold method based on the time properties of plastic scintillators equipped with silicon photomultipliers

A new high-granular compact time-of-flight neutron detector for the identification and energy measurement of neutrons produced in nucleus-nucleus interactions at the BM@N experiment, Dubna, Russia, at energies up to 4 AGeV is under development. The detector consists of approximately 2000 fast plastic scintillators, each with dimensions of 40$\times$40$\times$25 mm$^3$, equiped with SiPM (Silicon Photomultiplier) with an active area of 6$\times$6 mm$^2$. The signal readout from these scintillators will employ a single-threshold multichannel Time-to-Digital Converter (TDC) to measure their response time and amplitude using the time-over-threshold (ToT) method. This article focuses on the analytical description of the signals from the plastic scintillator detectors equipped with silicon photomultipliers. This description is crucial for establishing the ToT-amplitude relationship and implementing slewing correction techniques to improve the time resolution of the detector. The methodology presented in this paper demonstrates that a time resolution at the 70 ps level can be achieved for the fast plastic scintillator coupled with silicon photomultiplier with epitaxial quenching resistors

The PSD CBM Supermodule Response Study for Hadrons in Momentum Range 2 – 6 GeV/c at CERN Test Beams

The Projectile Spectator Detector (PSD) will be used at the Compressed Baryonic Matter (CBM) experiment at FAIR to measure the centrality and orientation of the reaction plane in heavy-ion collisions. A study of PSD supermodule response at proton and pion momentum range 2 – 6 GeV has been done at the CERN T10 beam line. The PSD supermodule is 3x3 array of 9 modules. Each module has transverse dimensions of 20x20 cm2 and longitudinal dimension of 5.6 interaction lengths. The modules have sandwich structure of 60 lead/scintillator layers with the sampling ratio 4:1. Light from each scintillator plate is collected by a WLS fiber. Scintillator light from 6 consecutive scintillator plates (one longitudinal section) is detected by a 3x3 mm2 Hamamatsu MPPC placed at the end of the module. In total, 10 MPPCs are used to detect light from 10 longitudinal sections in each module. Preliminary results on the longitudinal profile of energy deposition, linearity of the response and energy resolution of the supermodule are discussed

Measurement of Time Resolution of Scintillation Detectors with EQR-15 Silicon Photodetectors for the Time-of-Flight Neutron Detector of the BM@N Experiment

To study the dependence of the equation of state of high density nuclear matter on the term characterizing the isospin (proton-neutron) asymmetry of nuclear matter, it is necessary to measure azimuthal flow of neutrons as well as azimuthal flow of charged particles from a dense nuclear matter in the nuclear-nuclear collisions. For this purpose INR RAS is developing a new high-granular neutron detector which will be used in the BM@N experiment at the extracted beam of the Nuclotron accelerator at JINR (Dubna). This detector will identify neutrons and measure their energies in the heavy-ion collisions up to 4 GeV per nucleon. This article presents the results of measurements of the time resolution and light yields of samples of scintillation detectors with sizes 40$\times$40$\times$25 mm$^3$ that will be used in a neutron detector based on the currently available fast plastic scintillator manufactured by JINR using an EQR15 11-6060D-S photodetector for light readout. For comparison, the results of measurements for a detector of the same size with a fast scintillator EJ-230 and with the same type of photodetector are given. The measurements were made on cosmic muons as well as on the electron synchrotron "Pakhra" of the Lebedev Physical Institute of the Russian Academy of Sciences located in Troitsk, Moscow

IMPROVEMENT OF STANDARDS IN TERMS OF CONSTRUCTION CONTROL AND AS-BUILT DOCUMENTATION BASED ON QUALITY MANAGEMENT SYSTEMS

The authors of the study made a comparative analysis, and also highlighted the distinctive features in the practice of applying quality management systems in Russia and abroad. Recommendations on improving legislation in terms of technical regulation and standardization are given.Авторами исследования произведен сравнительный анализ, а также выделены отличительные особенности в практике применения систем менеджмента качества в России и за рубежом. Даны рекомендации по совершенствованию законодательства в части технического регулирования и стандартизации

ON THE LOCAL SUM CONJECTURE IN TWO DIMENSIONS

In this paper we give an elementary proof of the local sum conjecture in two dimensions. In a remarkable paper [CMN, arXiv:1810.11340], this conjecture has been established in all dimensions using sophisticated, powerful techniques from a research area blending algebraic geometry with ideas from logic. The purpose of this paper is to give an elementary proof of this conjecture which will be accessbile to a broad readership.Comment: 32 Page

Development of High Granular Neutron Time-of-Flight Detector for the BM@N experiment

The HGND (High Granular Neutron Detector) is developed for the BM@N (Baryonic Matter at Nuclotron) experiment on the extracted beam of the Nuclotron at JINR, Dubna. The HGND will be used to measure the azimuthal flow of neutrons produced with energies ranging from 300 to 4000 MeV in heavy-ion collisions at beam energies of 2--4 AGeV. The azimuthal flow of charged particles will be measured using the BM@N magnet spectrometer. The data on the azimuthal flow of neutrons will shed light on the study of the high-density Equation of State (EoS) of isospin-symmetric nuclear matter, which is crucial for studying astrophysical phenomena such as neutron stars and their mergers. The HGND has a highly granular structure with approximately 2000 plastic scintillation detectors (cells), each measuring 4$\times$4$\times$2.5 cm$^3$. These detectors are arranged in 16 layers, with 121 detectors in each layer, and are subdivided by copper absorber plates with a thickness of 3 cm. The light from each cell is detected with SiPM (Silicon Photomultiplier) with an active area of 6$\times$6 mm$^2$. Developed multi-channel TDC board based on the Kintex FPGA chip with a bin width of 100 ps will be used to perform precise timestamp and amplitude measurement using Time-over-Threshold (ToT) method. Good spatial resolution due to the high granularity together with a cell's time resolution of 100-150 ps ensures neutron reconstruction with good energy resolution. The design of the detector as well as the results from test measurements and simulations have been presented

On spectral minimal partitions: the case of the sphere

We consider spectral minimal partitions. Continuing work of the the present authors about problems for planar domains, [23], we focus on the sphere and obtain a sharp result for 3-partitions which is related to questions from harmonic analysis, in particular to a conjecture of Bishop