Defects analysis in self-organized nanopore arrays formed by anodization of aluminium at various temperatures

The self-organized anodization of aluminium in sulphuric acid was employed for formation of high-density nanostructures at various cell potentials and temperatures. The well-ordered arrangement of nanopores was obtained by two-step anodization process. The qualitative and quantitative analyses of defects were performed from SEM images of nanostructures. The Fourier transform (FFT) analyses showed that the uniformity of the triangular lattice increases gradually with increasing anodising potential independently of temperature. The order in the nanopore arrangement and size of well-ordered domains increase with increasing anodising potential for all studied temperatures. Quantitative analyses of defects, known as Delanuay triangulations, were performed for various anodising potentials and temperatures. The percentage of generated defects is constant at the cell potential between 15 and 23 V. At the temperature of 1 degree C, the percentage of defects equals to 20% while at temperatures of -8 or 10 degrees C reaches a value of about 30%. At the anodising potential of 25 V the percentage of generated defects in porous alumina is drastically reduced to about 10%, independently of the anodising temperature. The perfect nanopore arrangement on the anodised surface with the smallest number of defects can be obtained at 25 V.     

Geoenergy in Poland

This paper presents the current state of geothermal energy production in Poland and its future development prospects. At present, there are four geothermal heating plants in Poland. In addition, warm water is used in seven spa towns in balneology as well as in seven thermal swimming pools for recreational purposes. There has recently been an increase in the number of installed heat pumps in Poland – reaching 10,000 in 2010. In the near future the development of geothermics in Poland is forecast to continue. The first power and heat geothermal plant is being built in Uniejów whilst in more than ten other towns special swimming pool complexes using geothermal warm water are being built or designed. In the coming years heat pumps will be installed in living and office buildings as well as in public use buildings (mostly in newly built ones). Moreover, in Poland it is planned to use heat pumps in order to recover waste heat from factories and power plants.     

Extended viewing angle holographic display system with tilted SLMs in a circular configuration

This paper presents an extended viewing angle holographic display for reconstruction of real world objects in which the capture and display systems are decoupled. This is achieved by employing multiple tilted spatial light modulators (SLMs) arranged in a circular configuration. In order to prove the proper reconstruction and visual perception of holographic images the Wigner distribution function is employed. We describe both the capture system using a single static camera with a rotating object and a holographic display utilizing six tilted SLMs. The experimental results based on the reconstruction of computer generated and real world scenes are presented. The coherent noise removal procedure is described and implemented. The experiments prove the possibility to view images reconstructed in the display binocularly and with good quality.     

The Simple Method of Preparation of Highly Carboxylated Bacterial Cellulose with Ni- and Mg-Ferrite-Based Versatile Magnetic Carrier for Enzyme Immobilization

The bacterial cellulose (BC) is a versatile biopolymer of microbial origin characterized by high purity and unusual water and material properties. However, the native BC contains a low number of functional groups, which significantly limits its further application. The main goal of its effective modification is to use methods that allow the unusual properties of BC to be retained and the desired functional group to be efficiently introduced. In the present study, the new magnetic carrier based on functionalized citric acid (CA) bacterial cellulose was developed and tested to support critical industrial enzymes such as lipase B from Candida antarctica and phospholipase A from Aspergillus oryzae. The applied method allowed BC to be effectively modified by citric acid and a sufficient number of carboxylic groups to be introduced, up to 3.6 mmol of COOH per gram of dry mass of the prepared carrier. The DSC and TGA analyses revealed carrier stability at operational temperatures in the range of 20 °C to 100 °C and substantially influenced the amount of the introduced carboxyl groups on carrier properties. Both enzymes’ immobilization significantly improves their thermal stability at 60 °C without a significant thermal and pH optima effect. The analyzed enzymes showed good operational stability with a significant residual activity after ten cycles of repeated uses. The new magnetic carrier based on highly carboxylated bacterial cellulose has a high application capability as matrix for immobilization the various enzymes of industrial interest.     

A comparison of boundary graph grammars and context-free hypergraph grammars

Context-free hypergraph grammars and boundary graph grammars of bounded nonterminal degree have the same power, both for generating sets of graphs and for generating sets of hypergraphs. Arbitrary boundary graph grammars have more graph generating power than context-free hypergraph grammars, but they have the same hypergraph generating power. To obtain these results, several normal forms for boundary graph grammars are given. It is also shown that the class of boundary graph languages is closed under the operation of edge contraction, where the label of the edge indicates whether or not the edge should be contracted.     

Evaluation of glass samples for forensic purposes — An application of likelihood ratios and an information-theoretical approach

This article presents an experimental study about the influence of the selection of an adequate database for evidence evaluation using chemical profiles. Evidence evaluation in the forensic sense can be seen as the comparison of two glass objects, one of known origin, denoted as control glass, and typically would be from the scene of a crime, and the other one of unknown origin, termed recovered glass, which might be found in association with a suspect. The aim is to obtain some estimate of the weight of evidence for the degree of support to any of the hypothesis in the case, typically these might be that the control and recovered glass come from the same source (θ_p), and control and recovered glass come from different sources (θ_d). A likelihood ratio is considered a suitable measure of the evidential weight for the competing propositions. The observations are of the elemental composition of glass, measured using a Scanning Electron Microscopy, coupled with an Energy Dispersive X-ray spectrometer technique. A number of glass objects have been analyzed and their chemical profiles form a database which represents several sources of variation. In this paper questions surrounding the choice of observations to make are addressed empirically by assessing the impact of building each model using a database different from the one using for comparison. The performance of each evidence evaluation method is assessed by classical methods such as Tippett plots, or more recent information-theoretical approaches such as empirical cross-entropy (ECE) plots.The results show that several of the compositional elements are very robust to the selection of the background database, namely; calcium, silicon and sodium observed in their oxide forms. We also show that the likelihood ratio computed with the combination of these variables show a remarkable discriminating power, and good calibration, allowing them to be employed for the calculation of the strength of evidence in forensic case work.     

A variable-size local domain approach for increased design confidence in simulation-based optimization

Simulation-based design optimization utilizes computational models that rely on assumptions and approximations. There is a need therefore, to ensure that the obtained designs will exhibit the desired behavior as anticipated given the model predictions. The common approach to accomplish that is to validate the utilized computational models prior to the design optimization process. However, this is practically an impossible task especially for design problems with high-dimensional design and parameter spaces. We have recently proposed a different approach for maximizing confidence in the designs generated during a sequential simulation-based optimization process based on calibrating the computational models when necessary and within local subdomains of the design space. In that work, the size of the local domains was held fixed and not linked to uncertainty, and the confidence in designs was quantified using Bayesian hypothesis testing. In this article, we present an improved methodology. Specifically, we use a statistical methodology to account for uncertainty and to determine the size of the local domains at each stage of the sequential design optimization process using parametric bootstrapping that involves maximum likelihood estimators of model parameters. The sequential process continues until the local domain does not change from stage to stage during the design optimization process, ensuring convergence to an optimal design. The proposed methodology is illustrated with the design of a thermal insulator using one-dimensional, linear heat conduction in a solid slab with heat flux boundary conditions.     

Modeling computational limitations in H-Phy and Overlay-NoC architectures

High performance computing demands constant growth in computational power and services that can be offered by modern supercomputers. It requires technological and designing advances in the multiprocessor internal structures as well as novel computing models considering the very high computing demands. One of the increasingly important requirements of computing platforms is a functionality that allows efficient managing computational resources, i.e., monitor them, restrict an access to some part of the resources, account for computational service, or ensure reliability and quality of service when some resources are broken or disabled. In this paper, we present a new model describing computational limitations for processing tasks on multiprocessor systems. The model is implemented in Hardware-Physical (H-Phy) and Overlay-Network-on-Chip (Overlay-NoC) architectures. Both architectures and the model are described and analyzed. Experimentation system is also presented, together with simulation assumptions, results of research and their study. The paper provides complete models of H-Phy and Overlay-NoC structures with an ability to restrict processing resources.