Selected Experiences with Optimization Tests of the Kaplan-Type Hydraulic Turbines

The paper presents selected experience of the authors resulting from the optimization tests of double-regulated water turbines. Among the methods for measuring the discharge through the turbine used in such tests, particular attention was paid to index methods allowing to measure the relative discharge through the turbine-the index current meter method and the methods based on measuring the differential pressure between two points properly located at the turbine flow system （i.e., Winter-Kennedy method）. These methods contribute to effective reduction of the cost of optimizing the turbine that is extremely important for small hydropower plants regarding installed capacity. The paper presents selected examples of the optimization tests and experiences that arise from these tests.     

Fundamental methodological issues of syntactic pattern recognition

Fundamental open problems, which are frontiers of syntactic pattern recognition are discussed in the paper. Methodological considerations on crucial issues in areas of string and graph grammar-based syntactic methods are made. As a result, recommendations concerning an enhancement of context-free grammars as well as constructing parsable and inducible classes of graph grammars are formulated.     

Warm forming limits of rare earth-magnesium alloy ZEK100 sheet

Forming limit curves were developed for a rare earth-magnesium alloy, ZEK100-F, at temperatures between 25 and 350 °C in both the rolling (RD) and transverse directions (TD) of the sheet. ZEK100-F contains additions of zirconium (Zr) as a grain refining alloying element and a rare earth addition, neodymium (Nd), that promotes a weakened basal texture allowing enhanced slip activity at lower temperatures. Warm formability measurements were also performed on non-rare earth containing AZ31B-O to examine the relative performance of these two alloys. The ZEK100 material exhibited significantly better room temperature formability over AZ31B-O with a limiting dome height of 29 mm for ZEK100 compared to only 12 mm for the AZ31B-O. At elevated temperatures (250 °C) the difference in formability between the two alloys becomes less pronounced with a LDH of 40 and 36 mm for ZEK100 and AZ31B-O, respectively. What is particularly striking is the pronounced benefit of the rare earth alloyed material at intermediate temperatures, with an LDH of 37 mm at 150 °C which equals the LDH of AZ31B at 250 °C. Similar trends were determined in the measured forming limit curves reported here for the two alloys. The relative performance of the two alloys is largely attributed their initial textures. ZEK100-F also exhibits strongly anisotropic formability (RD versus TD) which can again be attributed to its’ initial texture.     

Identification of diffusive transport properties of poly(vinyl alcohol) hydrogels from reservoir test

In this paper the identification of diffusion coefficient, retardation factor and surface distribution coefficient for selected salts in poly(vinyl alcohol) hydrogels is performed. The identification of the transport parameters is based on the previously developed inverse problem technique using experimental data from the reservoir test and the solution of the diffusive transport equation with linear equilibrium sorption. The estimated values of diffusion coefficient are: for physiological fluid (6.30 ± 0.10) × 10^? 10 m²/s, for 1 M NaCl (6.42 ± 0.39) × 10^? 10 m²/s, and for 1 M KCl (7.94 ± 0.38) × 10^? 10 m²/s. The retardation factor for all tested materials and salts is equal or close to one. The average value of the effective surface distribution coefficient is equal to 0.5.     

Electrochemical Gas Sensor Materials Studied by Impedance Spectroscopy Part II: Reference Electrode and Solid Electrolyte/Electrode System

The behavior of the reference electrode (Na₂Ti₆O₁₃--TiO₂) and the electrode/solid electrolyte (Nasicon) interface of the electrochemical sensor were investigated by means of complex impedance spectra in the frequency range 0.1 Hz–1 MHz and at the temperatures between 298 K and 873 K. A plausible equivalent circuit involving two R-CPE elements connected in series was proposed. The results were discussed in terms of the brick-layer model. The parameters characterizing Schottky barrier occurring at the grain boundary interface were determined.     

Optimization of the form of a building on an oval base

The aim of this work is to analyze the possibility of optimizing an abstract, symmetrical with respect to the north–south axis form of a building with vertical walls and windows, and constant volume and height. The external south partitions of the building are walls with whole windowpanes. The heat losses through walls, floors, roof and the gain of solar radiation through transparent partitions with respect to their direct correlation with the shape of building form are next taken into consideration. The gain of solar energy for the north part of the building have been disregarded.     

Hand radiographs preprocessing, image representation in the finger regions and joint space width measurements for image interpretation

In this paper, the first stage of studies concerning the computer analysis of hand X-ray digital images is described. The images are preprocessed and then skeletization of the fingers is carried out. Then, the interphapangeal and metacarpophalangeal joints are detected and contoured. Joint widths are also measured. The obtained results largely concur with those obtained by other authors—see Beier et al. [Segmentation of medical images combining local, regional, global, and hierarchical distances into a bottom-up region merging scheme, Proc. SPIE 5747 (2005) 546-555], Klooster et al. [Automatic quantification of osteoarthritis in hand radiographs: validation of a new method to measure joint space width, Osteoarthritis and Cartilage 16 (1) (2008) 18-25], Ogiela et al. [Image languages in intelligent radiological palm diagnostics, Pattern Recognition 39 (2006) 2157-2165] and Ogiela and Tadeusiewicz [Picture languages in automatic radiological palm interpretation, Int. J. Appl. Math. Comput. Sci. 15 (2) (2005) 305-312].