On Application of Hyperfree Energy for the Description of Thermodynamics of Mobile Components in Nonstoichiometric Partially Open Ceramic Systems

Nonstoichiometric oxides form a new chapter in tailored materials. Founding and construction of thermodynamic functions related to solid (geologic, metallurgic) materials is traced showing interactions between Czech Professor F. Wald and Russians R.S. Kurnakov and D.S. Korzhinskiĭ and further developed by Czech P. Holba in the initial phase definition and related characterization of partially open systems. A gradual increase in thermodynamic concepts related to solid-state description is investigated in more detail. For the associated thermodynamic definition of the mobile component, the previously formulated hyperfree energy function, which was recently applied to several systems, was used. As a measure of the material disposition for the absorption of the free component, an innovative term of plutability is proposed, which allows the introduction of various forecaster variables such as temperature, pressure, and activity. Examples of practical application are examples of high-temperature superconducting materials, where the Czech school of thermodynamics is emphasized

CZECHOSLOVAK FOOTPRINTS IN THE DEVELOPMENT OF METHODS OF THERMOMETRY, CALORIMETRY AND THERMAL ANALYSIS

A short history on the development of thermometric methods are reviewed accentuating the role of Rudolf Bárta in underpinning special thermoanalytical conferences and new journal Silikáty in fifties as well as Vladimir Šatava mentioning his duty in the creation of the Czech school on thermoanalytical kinetics. This review surveys the innovative papers dealing with thermal analysis and the related fields (e.g. calorimetry, kinetics) which have been published by noteworthy postwar Czechoslovak scholars and scientists and by their disciples in 1950-1980. Itemized 227 references with titles show rich scientific productivity revealing that many of them were ahead of time even at international connotation

Stress coupling effect on ideal shear strength: tungsten as a case study

Mechanical response of a perfect bcc tungsten crystal to a multiaxial loading was investigated from first principles. The multiaxial stress state consisted of the shear stress and a superimposed compressive triaxial stress with various levels of differential stresses. The studied shear system was 111{110}. Results obtained within a relatively wide range of the compressive stresses showed that increasing hydrostatic triaxial stress (with zero differential stresses) increased the shear strength almost linearly. On the other hand, triaxial stresses with greater portion of the differential components did not have such a simple effect on the shear strength: We found a certain optimum value of the superimposed triaxial stress yielding the maximum shear strength. Any change (both increase and decrease) in the triaxial stress then reduced the ideal shear strength value

The Glassy State as the Lawfully Disarranged State. Vibration Uncertainty and Chaos-Like Movements

AbstractThe effect of a non-linear oscillator's vibrations (either in solids or in liquids) is the primary source of the amorphous state of the matter. The number of nonlinear oscillators (N.Os.) is considered to be very small at Tg (approximately 2.5%), and rises with the increase in temperature, reaching approximately 100% at the critical temperature Tc. In the main transition zone (covering the area between Tg and the crossover temperature Tcr), there are high amplitudes of N.Os. restricted by the particle neighbors and also by the internal energy related to the shear modulus. The shear modulus disappears above the Tcr, where the matter exists either in the form of a liquid or in the form of a rubber-like state (which is not considered in this study). In the present study, the liquid is considered as a heterogeneous structure, formed on the one hand by domains, which are responsible for the linear viscoelastic behavior, and on the other hand with the stand alone N.Os., which act as the trembling motion sources of the optically observed aspect of Brownian motion. Under the Tcr and Tg temperatures, the secondary β and tertiary γ processes are studied as well

Holba and Korzhinski Treatments of Hyperfree Energy Effective to Thermodynamics of Partially Open Solid-State Systems of Nonstoichiometric Oxides

Formulace a určování termodynamických funkcí souvisejících s pevnými (často geologickými) materiály. Je zaznamenána interakce mezi českým profesorem F. Waldem a ruským N.S. Kurnakovem a D.S. Korzhinskiĭm v rané definici fází a charakterizace částečně otevřených systémů. Vývoj thermodynamických pojmů týkajících se popisu v pevném stavu je upraven P. Holbou. Pro spojenou definici mobilních komponentů byla vyvinuta supervolná (hyperfree) energie a nově uvedena do praxe. Je vysvětlen termín přidružené plutabilityiFounding and determination of thermodynamic functions related to solid often geologic materials is traced showing interactions between Czech Professor F. Wald and Russian N.S. Kurnakov and D.S. Kozhinskiĭ in the early definition of phases and characterization of partly open systems. Development of thermodynamic notions regarding solid-state description is reviewed. For the coupled definition of a mobile component the hyperfree energy was developed and recently put into operation. Novel but somehow unusua term of the associated plutability is explained

Databases in materials science - Contemporary state and future

The state-of-the art of databases in materials science, understood as ordered and stored information, is discussed and the outlook for their development is deliberated. The text is divided in sections dealing with the glory, misery and future vision of databases, thermal analysis having its own comment.Web of Science6031110110

Energetika dnes a zítra: politika versus zdravý rozum vědy a techniky

Historická jistota člověka byl oheň, který se teprve v posledním dvoustoletí stal něčím víc než pouhým zdrojem tepla. Bádání a následný vznik nauky o teple přineslo porozumění řadě přírodních zákonů a poukázalo na možnost analogie termodynamických principů i v sousedních oblastech (ekonomika, společnost). Nepřetržitý vzrůst spotřeby energie způsobil i nárůst rozporu mezi potřebami člověka a přežitím přírody. Kontinuální spalování fosilních paliv pro výrobu elektrické energie má svoje termodynamické (zákony) a zdrojové meze (uhlí, plyn) stejně jako limity související s depozicí vznikajících odpadů. To vedlo k renesanci původních zdrojů (vítr, slunce) v nových hranicích moderních věd (fotovoltaika). Neúprosný souboj těch, co hledají pokročilé způsoby získávání energie, a těch, kteří na tom chtějí jen profitovat, je obrazem současné rozporuplné společnosti, ať už se jedná o klasické zdroje, použití nukleární energie či využití biopaliv. Alternativní využití vodíku jako přenašeče energie má své problémy, i když slibuje dosahování vyšších účinností v palivových článcích. Oblíbený koncept udržitelnosti (klima, skleníkový efekt) a související problém skutečné ceny energie je v mnoha oblastech zavádějící. Přednáška bude mít spíše populárně-vědecký než čistě odborný charakter.projektem OP VK PVBV – Popularizace vědy a badatelsky orientované výuky, reg. č. CZ.1.07/2.3.00/45.00

On the history and recent applications of hyperfree energy describing thermodynamics of mobile components in partly open ceramis systems

Nestechiometrické oxidy vytvářejí novou kapitolu v nově přizpůsobených materiálech. Založení a výstavba termodynamických funkcí souvisejících s pevnými (geologickými a metalurgickými ) materiály je sledována pomocí interakcí mezi českým profesorem F. Waldem a Rusy R.S. Kurnakov a D.S. Korzhinskiy v rané definici fází a charakterizaci částečně otevřených systémů. Vývoj termodynamických konceptů týkajících se popisu v pevném stavu je přezkoumán. Pro související definici mobilní komponenty byla definováma supervolná energie ve smysku přístupu P. Holby a aplikována na několik systémů. Novým termínem plutability je navržena jako míra citlivosti materiálu k volnému příjmu složek v důsledku různých prediktorů, jako je teplota, tlak a aktivita. Byly odvozeny Ehrenfestovy rovnice zahrnující se změny plutability.Nonstoichiometric oxides form a new chapter in tailored materials. Founding and construction of thermodynamic functions related to solid (geologic) materials is traced showing interactions between Czech Professor F. Wald and Russians R.S. Kurnakov and D.S. Korzhinskiy in the early definition of phases and characterization of partly open systems. Development of thermodynamic concepts regarding solid-state description is reviewed. For the associated definition of a mobile component the hyperfree energy was invented and recently applied on several systems. A novel term plutability is put forward as a measure of material susceptibility towards free component uptake as a result of varying predictors such as temperature, pressure and activity. Ehrenfest-like equations involving the changes of plutabilities were derived