Analysis of emptiness (lacunarity) as a measure of the degree of space filling and of the internal structure of a set

The study presents a comparative evaluation of emptiness (lacunarity) in model structures with different types of inhomogeneity of dispersed particle distributions. The research on emptiness (lacunarity) as a measure of the degree of space filling and, at the same time, of the internal characterization of a set has been based on the optimal covering and gliding-box methods.     

Evaluation of various integration algorithms for transient inelastic response of shear walls

Inelastic dynamic response of building walls made of reinforced concrete is considered by using various explicit and implicit algorithms. The numerical examples show the computational efficiency of algorithms for different low and high walls.     

Aspects of dSpace in contemporary design

Computer dependent design space is illustrated with the recent international competition project for Kowloon Arts Center. The spatial condition of design resulted from the deployment of Euclidian geometry and use of the nonrational, complex surfaces. Another aspect of computer dependent space was rooted in the contemporary work situation where architects located on the three different continents collaborated in distributed mode over the internet. The resulting project confirms the creative potential of the above aspects of the digital space in contemporary design.     

Textural and microstructural transformation of Cu damascene interconnects after annealing

Influence of annealing on the textural and microstructural transformation of Cu interconnects having various line widths is investigated. Two types of annealing steps have been considered here: room temperature over 6 months and 200°C for 10 min. The texture was determined by x-ray diffraction (XRD) of various cross-sectional profiles after electropolishing, and the surface, microstructure, and grain boundary character distribution (GBCD) of Cu interconnects were characterized using electron backscattered diffraction (EBSD) techniques. In order to analyze a relationship between the stress distribution and textural evolution in the samples, microstresses were calculated with decreasing line widths at 200°C using finite element modeling (FEM). In this investigation, it was found that the inhomogeneity of stress distribution in Cu interconnects is an important factor, which is necessary for understanding textural transformation after annealing. A new interpretation of textural evolution in damascene interconnects lines after annealing is suggested, based on the state of stress and the growth mechanisms of Cu electrodeposits.     

Multifractal detection of overlaps based on a stereometric analysis of a fracture surface: Assumptions

The paper presents theoretical assumptions of an analysis of stereometric files for the purpose of the detection of the occurrence of overlaps. The measured data of a fracture surface were obtained using a profilographometer. An algorithm has been developed based on the probability of the occurrence of maximum Euclidean distances in the investigated areas of the stereometric image. An analysis of real fractures and overlaps [Stach S, Roskosz S, Cwajna J, Cybo J. Graphic visualization of overlaps occurring in sintered carbides' fractures, Materials Characterization 2006-this issue. doi:10.1016/j.matchar.2006.01.007. [1]] has corroborated a high effectiveness of multifractal detection.     

Changes in structure of psoas major and minor and semitendinosus muscles of calves, heifers and cows during post-mortem ageing

Changes occurring during post-mortem ageing in structure of psoas major and minor (PM) and semitendinosus (ST) muscles of calves, heifers and cows were observed. Samples from muscles taken 3 h after slaughter and after 6 and 12 days of storage at the temperature of 4?°C were analysed using light and transmission electron microscopy. Three hours after slaughter muscle fibres were close to each other and sarcomeres showed normal structure of A- and I-bands, M-lines and Z-disks. The space between myofibrils and sarcolemma and also between single myofibrils in muscle fibres increased during storage. Structure of sarcomeres underwent continuous degradation, length of sarcomeres increased due to enlargement of I-bands accompanied by Z-disk degradation. During ageing structural changes in myofibrils took place faster, were more intensive in muscles of younger animals and were more extensive and faster in PM than in ST muscles.     

Transparent flexible plastic substrates for organic light-emitting devices

In this paper, we describe the properties of flexible plastic substrates with a transparent conducting electrode (TCE), which are important for organic light-emitting devices (OLEDs). Specifically, we have evaluated the TCE electrical resistivity, surface roughness, electrode patterning, optical transmission, and the substrate water vapor/oxygen transmission. We have studied the effect of ultraviolet (UV)-ozone treatment on the TCE surface by using contact angle measurements and x-ray photoelectron spectroscopy (XPS). A decrease in the advancing contact angle by 30–40° and an increase of oxygen content on the TCE surface by 10 at.% were observed after the UV-ozone treatment. These changes facilitate the polymer adhesion to the TCE surface and increase the TCE surface work function, respectively. A sheet resistance of 12–13 Ω/□, an optical transmission greater than 80% over the visible range, and a surface roughness of 1.4–2.2-nm RMS over 50×50 μm² have been obtained for the plastic substrates. These properties are adequate for OLED applications based on United States Display Consortium specifications. Finally, we have found that a combination of hydrogenated amorphous silicon-nitride and silicon-oxide layers deposited on one side of the substrate at low-temperature reduces the water vapor and oxygen transmission rates (TRs) to less than 10⁻⁵ g/cm²-day-atm and about 10⁻⁷ cc/cm²-day-atm, respectively.     

Basic principles of thermal degradation and thermal stabilization of poly(vinyl chloride). Synergism of stabilizer action

Changes in the quantities of active stabilizing components during thermal aging of plasticized poly(vinyl chloride) containing a mixture of calcium and zinc stearates were analyzed. A mathematical model of the stabilization process by using the stabilizer mixture and a computer program for analyzing the process of PVC thermal degradation after the beginning of HCl evolution are given.     

Calculation of phase equilibria for AISI M2 high-speed steel

Thermo-calc computations have been made for the iron-rich corner of the system Fe-Cr-Mo-W-V-C to obtain phase equilibria for AISI M2 high-speed steel (German designation S-6-5-2). The calculations describe the main transformation temperatures of this steel with good accuracy. The phases which are present during austenitization and their volume fractions are also correctly accounted for. The solidification sequence of the M2 steel, and in particular the occurrence of M₂C in the ledeburitic eutectic, can be explained if the segregation of alloying elements and carbon in the interdendritic spaces is taken into account. The secondary hardening precipitates can be described in satisfactory approximation on the basis of local two-phase equilibria between each carbide and the matrix, indicating that their compositions are essentially determined by the nucleation process.