Disorder chaos in spin glasses

We investigate numerically disorder chaos in spin glasses, i.e. the sensitivity of the ground state to small changes of the random couplings. Our study focuses on the Edwards-Anderson model in d=1,2,3 and in mean-field. We find that in all cases, simple scaling laws, involving the size of the system and the strength of the perturbation, are obeyed. We characterize in detail the distribution of overlap between ground states and the geometrical properties of flipped spin clusters in both the weak and strong chaos regime. The possible relevance of these results to temperature chaos is discussed.Comment: 7 pages, 8 figures, replaced with accepted versio

Ultrametric probe of the spin-glass state in a field

We study the ultrametric structure of phase space of one-dimensional Ising spin glasses with random power-law interaction in an external random field. Although in zero field the model in both the mean-field and non-mean-field universality classes shows an ultrametric signature [Phys. Rev. Lett. 102, 037207 (2009)], when a field is applied ultrametricity seems only present in the mean-field regime. The results for the non-mean field case in an external field agree with data for spin glasses studied within the Migdal-Kadanoff approximation. Our results therefore suggest that the spin-glass state might be fragile to external fields below the upper critical dimension.Comment: 5 pages, 4 figures, 1 tabl

Modyfikacja powierzchni stopu Ti-6Al-4V metodą PEO-EPD w zawiesinie ZrSiO4

Investigations on the surface modification of the Ti-6Al-4V alloy by plasma electrolytic oxidation are reported here. The oxidation process was carried out in a solution containing a zirconium silicate (ZrSiO4) suspension and sodium hydroxide (NaOH). Anodising was realised at voltages in a range from 100 V to 250 V. It was found that the morphology of the sample surface did not change during the oxidation of the alloy at 100 V. Application of voltages higher than 100 V led to the incorporation of zirconium silicate into the formed oxide layer and to significant changes of the surface morphology

Distribution of partition function zeros of the ±J\pm J model on the Bethe lattice

The distribution of partition function zeros is studied for the $\pm J$ model of spin glasses on the Bethe lattice. We find a relation between the distribution of complex cavity fields and the density of zeros, which enables us to obtain the density of zeros for the infinite system size by using the cavity method. The phase boundaries thus derived from the location of the zeros are consistent with the results of direct analytical calculations. This is the first example in which the spin glass transition is related to the distribution of zeros directly in the thermodynamical limit. We clarify how the spin glass transition is characterized by the zeros of the partition function. It is also shown that in the spin glass phase a continuous distribution of singularities touches the axes of real field and temperature.Comment: 23 pages, 12 figure

Modification of niobium surfaces using plasma electrolytic oxidation in silicate solutions

Herein, a study of the plasma electrolytic oxidation (PEO) of niobium in an anodising bath composed of potassium silicate (K2SiO3) and potassium hydroxide (KOH) is reported. The effects of the K2SiO3 concentration in the bath and the process voltage on the characteristics of the obtained oxide layers were assessed. Compact, barrier-type oxide layers were obtained when the process voltage did not exceed the breakdown potential of the oxide layer. When this threshold was breached, the morphology of the oxide layer changed markedly, which is typical of PEO. A significant amount of silicon, in the form of amorphous silica, was incorporated into the oxide coatings under these conditions compared with the amount obtained with conventional anodising. This surface modification technique led to an improvement in the corrosion resistance of niobium in Ringer’s solution, regardless of the imposed process conditions

Phase Transitions and Computational Difficulty in Random Constraint Satisfaction Problems

We review the understanding of the random constraint satisfaction problems, focusing on the q-coloring of large random graphs, that has been achieved using the cavity method of the physicists. We also discuss the properties of the phase diagram in temperature, the connections with the glass transition phenomenology in physics, and the related algorithmic issues.Comment: 10 pages, Proceedings of the International Workshop on Statistical-Mechanical Informatics 2007, Kyoto (Japan) September 16-19, 200

DICE: Exploiting All Bivariate Dependencies in Binary and Multary Search Spaces

Although some of the earliest Estimation of Distribution Algorithms (EDAs) utilized bivariate marginal distribution models, up to now, all discrete bivariate EDAs had one serious limitation: they were constrained to exploiting only a limited O(d) subset out of all possible O(d2) bivariate dependencies. As a first we present a family of discrete bivariate EDAs that can learn and exploit all O(d2) dependencies between variables, and yet have the same run-time complexity as their more limited counterparts. This family of algorithms, which we label DICE (DIscrete Correlated Estimation of distribution algorithms), is rigorously based on sound statistical principles, and particularly on a modelling technique from statistical physics: dichotomised multivariate Gaussian distributions. Initially (Lane et al. in European Conference on the Applications of Evolutionary Computation, Springer, 1999), DICE was trialled on a suite of combinatorial optimization problems over binary search spaces. Our proposed dichotomised Gaussian (DG) model in DICE significantly outperformed existing discrete bivariate EDAs; crucially, the performance gap increasingly widened as dimensionality of the problems increased. In this comprehensive treatment, we generalise DICE by successfully extending it to multary search spaces that also allow for categorical variables. Because correlation is not wholly meaningful for categorical variables, interactions between such variables cannot be fully modelled by correlation-based approaches such as in the original formulation of DICE. Therefore, here we extend our original DG model to deal with such situations. We test DICE on a challenging test suite of combinatorial optimization problems, which are defined mostly on multary search spaces. While the two versions of DICE outperform each other on different problem instances, they both outperform all the state-of-the-art bivariate EDAs on almost all of the problem instances. This further illustrates that these innovative DICE methods constitute a significant step change in the domain of discrete bivariate EDAs

Production of foamed polypropylene products with metal inserts

Przedstawiono wyniki prac dotyczących możliwości produkcji innowacyjnych kształtek otrzymywanych ze spienionego polipropylenu z metalowymi wkładkami. Projekt obejmował zarówno prace projektowe badawczo-rozwojowe jak i prace wdrożeniowe na linii produkcyjnej. W wyniku prac badawczo-rozwojowych prowadzonych przez firmę IZOBLOK S.A. potwierdzono możliwość otrzymywania rozwiązania w postaci wzmocnionych kształtek z EPP.Results of work dealing with the possibility of producing innovative EPP (foamed polypropylene) profiles with metal inserts are presented in the paper. The project included both design part and its implementation in a process line. As a result of research and development work carried out by IZOBLOK, the possibility of obtaining reinforced EPP parts was confirmed

Miners in Upper Silesia: culture, identity, heritage

Niniejsza praca przedstawia kulturotwórczy aspekt górnictwa na obszarze Górnego Śląska, skupiając się szczególnie na dziedzictwie kulturowym owego regionu w ujęciu niematerialnym. Celem pracy jest ukazanie społecznego wpływu kultury górniczej na tożsamość robotników i relacje tworzone w kręgach społecznych, do których należą. W pierwszej części przedstawiony został m.in. kontekst historyczny powstania kultury górniczej na Górnym Śląsku. Kolejna część pracy traktuje o relacjach i hierarchii wśród załogi kopalni, górniczym etosie, języku, oraz pojęciu swojskości i obcości w świadomości robotników. W ostatnim, trzecim rozdziale zwrócono uwagę na wpływ górnictwa na kształtowanie ról społecznych w dwóch kręgach występujących poza miejscem pracy – sąsiedztwie osiedli robotniczych oraz rodzinie górniczej. Z rozważań zawartych w pracy wynika, że obecność górnictwa w regionie miała różny wpływ na Górnoślązaków, w zależności od ich przynależności do danych kręgów społecznych. W przypadku robotników, praca wydaje się przede wszystkim kształtować ich tożsamość, na którą składają się m.in. cechy ich osobowości oraz pozycja w hierarchii. Z kolei poza kręgiem współpracowników, na osiedlu i w tradycyjnej rodzinie górniczej, znacznie ważniejsze są role, przypisywane poszczególnym członkom zbiorowości, silnie związane z wykonywanym przez mężczyzn zawodem. Autorka ma jednocześnie świadomość, iż powyższych wniosków nie można w pełni odnieść do obecnego stanu kultury górniczej, znajdującej się w procesie transformacji. W sytuacji, gdy górnośląskie kopalnie są zamykane, wiele elementów dziedzictwa przemysłowego owego regionu zanika lub zmienia swój charakter. Badanie tych procesów jest możliwe wyłącznie w momencie, gdy scharakteryzujemy górniczą kulturę w jej tradycyjnym wymiarze – niniejsza praca jest więc stworzona z myślą o potrzebie przyszłych badań porównawczych, opisujących zmiany zachodzące w kulturze i społeczności górniczej.The present work portrays the culture-forming aspect of the mining industry in Upper Silesia, focusing on its intangible cultural heritage. The work aims to present the social impact of the mining culture on the identity of miners and the relationships built in the social circles to which they belong. In the first chapter, the author presents, among others, the historical context of the birth of the mining culture in Upper Silesia. The next one describes the relationships and hierarchy among the workers, their ethos, language and the perception of “the Other” in their community. In the last, third chapter, the author pays attention to the impact of the mining industry on shaping the social roles in two circles unrelated to the workplace – the neighbourhood of an industrial colony and a miner’s family. The results of this analysis show that the presence of the mining industry had different kinds of impact on Upper Silesians, depending on their affiliation to given social circles. In case of the workers, their job seems to primarily shape their identity, which consists of, among others, their personality traits and position in the hierarchy. On the other hand, in the industrial colony and the miner’s family, a much more important part is played by the social roles, assigned to each member of the community, largely influenced by the men’s profession. Still, the author is aware that these conclusions can’t be fully applied to the current state of the mining culture, as it is constantly being transformed. While the Upper Silesian mines are being closed, various elements of the region’s industrial heritage are being altered or disappear. The study of these processes is only possible after characterizing the mining culture in its traditional form – the present work is therefore created in consideration for the need for future comparative research, describing the changes in the mining culture and community

An innovative system for monitoring the mechanical properties of concrete

Powszechnie stosowane metody normowe określania cech mechanicznych betonu nie uwzględniają rzeczywistych warunków dojrzewania betonu. Cechy betonu w konstrukcji różnią się od wartości uzyskiwanych laboratoryjnie. W procesie wiązania betonu wydziela się ciepło, które wpływa na tempo zmian cech mechanicznych betonu w konstrukcji. Drugim czynnikiem jest wpływ zastosowania kruszywa na uzyskiwane wartości modułów sprężystości betonu. W artykule przedstawiono wyniki badań cech mechanicznych betonu wiaduktu WG-4 na obwodnicy Raciborza. Na potrzeby podejmowania decyzji o sprężaniu oraz aktualizacji podniesienia wykonawczego określono laboratoryjnie właściwości betonu pielęgnowanego w warunkach znormalizowanych i odwzorowanych. Zastosowano innowacyjny system monitoringu cech mechanicznych betonu, który uwzględniał rzeczywiste warunki dojrzewania betonu w konstrukcji. Uzyskane wyniki z badań pozwoliły zminimalizować ryzyka związane z podejmowaniem decyzji na budowie.Commonly used standard methods for determining the mechanical properties of concrete do not take into account the actual conditions of concrete maturation. The characteristics of concrete in the structure differ from the values obtained in the laboratory. In the process of setting concrete, heat is released, which affects the rate of changes in the mechanical properties of concrete in the structure. The second factor is the influence of the use of aggregate on the obtained values of concrete elasticity modulus. The article presents the results of research on the mechanical properties of the concrete of the WG-4 viaduct on the Racibórz beltway. For the purposes of making a decision on prestressing and updating the construction technology, laboratory characteristics of cured concrete in standardized and mapped conditions were determined. An innovative system for monitoring the mechanical properties of concrete was used, which took into account the actual conditions of concrete maturation in the structure. The obtained results from the research allowed to minimize the risks related to making decisions on the construction site