Kinetika rekristalizacije tijekom vrućeg oblikovanja čelika

The theory of kinetics of static recrystallization of steel during hot forming links the phenomenon to certain critical strain, grain size, strain rate, activation energy and temperature. The basic description is provided by the Avrami equation. An overview of equations used was compiled and comments on selected parameters prepared.Teorija kinetike statičke rekristalizacije čelika tijekom vrućeg oblikovanja ovu pojavu povezuje s kritičnom deformacijom, veličinom zrna, brzinom deformacije, aktivacijskom energijom te s temperaturom. Osnovni opis pruža Avrami jednadžba. Rad pruža pregled korištenih jednadžbi i raspravu pojedinih parametara

Kinetika rekristalizacije tijekom vrućeg oblikovanja čelika

The theory of kinetics of static recrystallization of steel during hot forming links the phenomenon to certain critical strain, grain size, strain rate, activation energy and temperature. The basic description is provided by the Avrami equation. An overview of equations used was compiled and comments on selected parameters prepared.Teorija kinetike statičke rekristalizacije čelika tijekom vrućeg oblikovanja ovu pojavu povezuje s kritičnom deformacijom, veličinom zrna, brzinom deformacije, aktivacijskom energijom te s temperaturom. Osnovni opis pruža Avrami jednadžba. Rad pruža pregled korištenih jednadžbi i raspravu pojedinih parametara

Bilateral coronary artery to pulmonary trunk fistulae detected by coronary angiography and evaluated by ECG-gated SPECT myocardial perfusion imaging: report of two cases

Coronary artery fistulae (CAF) are anomalies related to coronary artery abnormal termination. This is a very rare congenital malformation accounting for about 0.2–0.4% of congenital cardiac anomalies, but in some patients it can be haemodynamically important. Single-photon emission computed tomography or positron emission tomography myocardial perfusion imaging (MPI) using radioactive agents is widely used in clinical practice for cardiac ischaemia detection as a very sensitive and non-invasive tool. We are going to present 2 patients with bilateral CAFs to the pulmonary trunk without signs of the rest or stress ischaemia in MPI.

Granular circulation in a cylindrical pan: simulations of reversing radial and tangential flows

Granular flows due to simultaneous vertical and horizontal excitations of a flat-bottomed cylindrical pan are investigated using event-driven molecular dynamics simulations. In agreement with recent experimental results, we observe a transition from a solid-like state, to a fluidized state in which circulatory flow occurs simultaneously in the radial and tangential directions. By going beyond the range of conditions explored experimentally, we find that each of these circulations reverse their direction as a function of the control parameters of the motion. We numerically evaluate the dynamical phase diagram for this system and show, using a simple model, that the solid-fluid transition can be understood in terms of a critical value of the radial acceleration of the pan bottom; and that the circulation reversals are controlled by the phase shift relating the horizontal and vertical components of the vibrations. We also discuss the crucial role played by the geometry of the boundary conditions, and point out a relationship of the circulation observed here and the flows generated in vibratory conveyors.Comment: 10 pages, 8 figure

Structural phase transitions and their influence on Cu+ mobility in superionic ferroelastic Cu6PS5I single crystals

The structural origin of Cu+ ions conductivity in Cu6PS5I single crystals is described in terms of structural phase transitions studied by X-ray diffraction, polarizing microscope and calorimetric measurements. Below the phase transition at Tc=(144-169) K Cu6PS5I belongs to monoclinic, ferroelastic phase, space group Cc. Above Tc crystal changes the symmetry to cubic superstructure, space group F-43c (a=19.528); finally at 274K disordering of the Cu+ ions increases the symmetry to F-43m, (a=9.794). The phase transition at 274K coincides well with a strong anomaly in electrical conductivity observed in the Arrhenius plot. Diffusion paths for Cu+ ions are evidenced by means of the atomic displacement factors and split model. Influence of the copper stechiometry on the Tc is also discussed.Comment: conference pape

A Mathematical Model of COVID-19 Transmission

Disease transmission is studied through disciplines like epidemiology, applied mathematics, and statistics. Mathematical simulation models for transmission have implications in solving public and personal health challenges. The SIR model uses a compartmental approach including dynamic and nonlinear behavior of transmission through three factors: susceptible, infected, and removed (recovered and deceased) individuals. Using the Lambert W Function, we propose a framework to study solutions of the SIR model. This demonstrates the applications of COVID-19 transmission data to model the spread of a real-world disease. Different models of disease including the SIR, SIRmp and SEIRρqr model are compared with respect to their ability to predict disease spread. Physical distancing impacts and personal protection equipment use are discussed with relevance to the COVID-19 spread

A study of the gravitational wave form from pulsars II

We present analytical and numerical studies of the Fourier transform (FT) of the gravitational wave (GW) signal from a pulsar, taking into account the rotation and orbital motion of the Earth. We also briefly discuss the Zak-Gelfand Integral Transform. The Zak-Gelfand Integral Transform that arises in our analytic approach has also been useful for Schrodinger operators in periodic potentials in condensed matter physics (Bloch wave functions).Comment: 6 pages, Sparkler talk given at the Amaldi Conference on Gravitational waves, July 10th, 2001. Submitted to Classical and Quantum Gravit

Optimization of an Alkylpolyglucoside-Based Dishwashing Detergent Formulation.

The aim of this work was to formulate and optimize the washing performance of an alkylpolyglucoside-based dishwashing detergent. The liquid detergent was formulated with five ingredients of commercial origin: anionic (linear sodium alkylbenzenesulfonate and sodium laurylethersulfate), nonionic (C12–C14 alkylpolyglucoside) and zwitterionic (a fatty acid amide derivative with a betaine structure) surfactants, and NaCl for viscosity control. In addition to the plate test, other properties were investigated including ‘‘cloud point’’, viscosity, and emulsion stability. Statistical analysis software was used to generate a central composite experimental design. Then, a second order design and analysis of experiments approach, known as the Response Surface Methodology, was set up to investigate the effects of the five components of the formulation on the studied properties in the region covering plausible component ranges. The method proved to be efficient for locating the domains of concentrations where the desired properties were met

Modelling of COVID-19 Using Fractional Differential Equations

In this work, we have described the mathematical modeling of COVID-19 transmission using fractional differential equations. The mathematical modeling of infectious disease goes back to the 1760s when the famous mathematician Daniel Bernoulli used an elementary version of compartmental modeling to find the effectiveness of deliberate smallpox inoculation on life expectancy. We have used the well-known SIR (Susceptible, Infected and Recovered) model of Kermack & McKendrick to extend the analysis further by including exposure, quarantining, insusceptibility and deaths in a SEIQRDP model. Further, we have generalized this model by using the solutions of Fractional Differential Equations to test the accuracy and validity of the mathematical modeling techniques against Canadian COVID-19 trends and spread of real-world disease. Our work also emphasizes the importance of Personal Protection Equipment (PPE) and impact of social distancing on controlling the spread of COVID-19

Medication use in pregnancy: a cross-sectional, multinational web-based study

Objectives: Intercountry comparability between studies on medication use in pregnancy is difficult due to dissimilarities in study design and methodology. his study aimed to examine patterns and factors associated with medications use in pregnancy from a multinational perspective, with emphasis on type of medication utilised and indication for use. Design: Cross-sectional, web-based study performed within the period from 1 October 2011 to 29 February 2012. Uniform collection of drug utilisation data was performed via an anonymous online questionnaire. Setting: Multinational study in Europe (Western, Northern and Eastern), North and South America and Australia. Participants: Pregnant women and new mothers with children less than 1 year of age. Primary and secondary outcome measures: Prevalence of and factors associated with medication use for acute/short-term illnesses, chronic/long-term disorders and over-the-counter (OTC) medication use. Results: The study population included 9459 women, of which 81.2% reported use of at least one medication (prescribed or OTC) during pregnancy. Overall, OTC medication use occurred in 66.9% of the pregnancies, whereas 68.4% and 17% of women reported use of at least one medication for treatment of ute/short-term illnesses and chronic/long-term disorders, respectively. The extent of self-reported medicated illnesses and types of medication used by indication varied across regions, especially in relation to urinary tract infections, depression or OTC nasal sprays. Women with higher age or lower educational level, housewives or women with an unplanned pregnancy were those most often reporting use of medication for chronic/long-term disorders. Immigrant women in Western (adjusted OR (aOR): 0.55, 95% CI 0.34 to 0.87) and Northern Europe (aOR: 0.50, 95% CI 0.31 to 0.83) were less likely to report use of medication for chronic/long-term disorders during pregnancy than nonimmigrants. Conclusions: In this study, the majority of women in Europe, North America, South America and Australia used at least one medication during pregnancy. There was a substantial inter-region variability in the types of medication used