Structural hierarchy of rock masses and the mechanisms of its formation

The formation mechanisms for the structural hierarchy in geological media are discussed. It is shown that the formation of such a hierarchy is caused by certain external and internal circumstances. The first ones consist in the fact that, because of external actions, the Earth’s poles continuously execute the translational and rotational motions responsible for a regular structure of rock fracture and for the appearance of the scale factor √2. The second ones consist in the fact that, under the action of many random factors and because of external actions, during the formation of geological media there appear dissipative structures and, hence, some self-similar fractal structures are formed.     

Reply to Nathan: How to reconstruct the causal argument

Nicholas Nathan tries to resist the current version of the causal argument for sense-data in two ways. First he suggests that, on what he considers to be the correct re-construction of the argument, it equivocates on the sense of proximate cause. Second he defends a form of disjunctivism, by claiming that there might be an extra mechanism involved in producing veridical hallucination, that is not present in perception. I argue that Nathan’s reconstruction of the argument is not the appropriate one, and that, properly interpreted, the argument does not equivocate on proximate cause. Furthermore, I claim that his postulation of a modified mechanism for hallucinations is implausibly ad hoc.     

A numerical and experimental investigation of the interactions between a non‐uniform planar array of incompressible free jets

The interaction between multiple incompressible air jets has been studied numerically and experimentally. The numerical predictions have been first validated using experimental data for a single jet configuration. The spreading features of five unequal jets in the configuration of one larger central jet surrounded by four smaller equi‐distant jets, have been studied, for different lateral spacing ratios of 1.5, 2.0 and 2.5 and a central jet Reynolds number of 1.24×105 (corresponding to a Mach number of 0.16). Flow of five equal jets has also been simulated, for the sake of comparison. The jet interactions commence at an axial distance of about 3–4 diameters and complete by an axial distance of about 10 diameters for the lowest spacing ratio of 1.5. For larger spacing ratios, the length required for the start and completion of jet interaction increase. Peripheral jets bend more towards the central jet and merge at a smaller distance, when their sizes are smaller than that of the central jet. The entrainment ratio for multiple jets is higher than that for a single jet. Excellent agreement is observed between the experimental data and theoretical predictions for both mean flow field and turbulent quantities, at regions away from the jet inlet. The potential core length and initial jet development, however, are not predicted very accurately due to differences in the assumed and actual velocity profiles at the jet inlet. Copyright © 2004 John Wiley & Sons, Ltd.     

New liquid‐crystalline poly(ester amide)s: The role of nitro groups in the phase behavior

New hydrogen‐bonded liquid‐crystalline poly(ester amide)s (PEA)s were obtained from 1,4‐terephthaloyl[bis‐(3‐nitro‐N‐anthranilic acid)] (5) or 1,4‐terephthaloyl[bis‐(N‐anthranilic acid)] (6), with or without nitro groups, respectively, through the separate condensation of each with hydroquinone or dihydroxynaphthalene. The dicarboxylic monomers were synthesized from 2‐aminobenzoic acid. The phase behavior of the monomers and polymers were studied with differential scanning calorimetry, polarized light microscopy, and wide‐angle X‐ray diffraction methods. Monomer 5, containing nitro groups, exhibited a smectic liquid‐crystalline phase, whereas the texture of monomer 6 without nitro groups appeared to be nematic. The PEAs containing nitro groups exhibited polymorphism (smectic and nematic), whereas those without nitro groups exhibited only one phase transition (a nematic threaded texture). The changes occurring in the phase behavior of the polymers were explained by the introduction of nitro groups. © 2004 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 42: 1289–1298, 2004     

Determination of nickel in alloys and plant leaves with salicylaldehyde 3-oxobutanoylhydrazone by spectrophotometry.

A simple and highly sensitive reagent of salicylaldehyde 3-oxobutanoylhydrazone (salicylaldehyde acetoacetic acid hydrazone, SAAH) was synthesized and studied for the spectrophotometric determination of nickel in detail. In the pH range 6, which greatly increased the selectivity, nickel reacted with SAAH to form a 1:1 yellow complex, having a sensitive absorption peak at 405 nm. Under the optimal conditions, Beer's law was obeyed over the range from 0.0117 to 0.1174 microg cm(-3). The apparent molar absorptivity was 3.025 x 10(5) dm3 mol(-1) cm(-1). The detection limit and the variation coefficient were found to be 1.752 ng cm(-3) and 1.0%, respectively. The method has been applied to the quantitative determination of nickel in different alloys and leaves.     

Extractive spectrophotometric determination of Cobalt(II) in synthetic and pharmaceutical samples using Cyanex 923.

Cyanex 923 has been proposed as a sensitive analytical reagent for the direct extractive spectrophotometric determination of cobalt(II). Cobalt(II) forms a blue-colored complex with Cyanex 923 in the organic phase. The maximum absorbance of the complex is measured at 635 nm. Beer's law was obeyed in the range 58.9 - 589.0 microg of cobalt. The molar absorptivitiy and Sandell's sensitivity of the complex was calculated to be 6.79 x 10920 l mol(-1) cm(-1) and 0.088 microg cm(-2), respectively. The nature of the extracted species was found to be Co(SCN)2 x 2S. An excellent linearity with a correlation coefficient value of 0.999 was obtained for the Co(II)-Cyanex 923 complex. Stability and regeneration of the reagent (Cyanex 923) for reuse is the main advantage of the present method. The method was successfully applied to the determination of cobalt in synthetic mixtures and pharmaceutical samples was found to give values close to the actual ones. Standard alloy samples, such as high-speed tool BCS 484 and 485, have been tested for the determination of cobalt for the purpose of validating the present method. The results of the proposed method are comparable with atomic absorption spectrometry and were found to be in good agreement.     

A Second-Order Theory for Electron Plasma Solitary Waves in a Cylindrical Waveguide

To describe the long time asymptotic behaviour of weakly nonlinear plasma waves propagating in a strongly magnetized plasmafilled cylindrical waveguide the usual KDV equation which is first order in wave amplitude is extended to second order including the effects of finite temperature, mobile ions and giving a proper treatment to the radial co-ordinate for all possible modes of propagation. The second-order effects on the first-order solitary wave profile, phase speed and first order correction to the wavelength are all determined and discussed.     

The sliding-window packet switch: a new class of packet switch architecture with plural memory modules and decentralized control

Shared-memory based packet switches are known to provide the best possible throughput performance for bursty data traffic in high-speed packet networks and internets compared with other buffering strategies under conditions of identical memory resources deployed in the switch. However, scaling of shared-memory packet switches to a larger size has been restricted mainly due to the physical limitations imposed by the memory-access speed and the centralized control for switching functions in shared-memory switches. A new scalable architecture for a shared-memory packet switch, called the sliding-window (SW) switch, is proposed to overcome these limitations. The SW switch introduces a new class of switching architecture, where physically separate multiple memory modules are logically shared among all the ports of the switch, and the control is decentralized. The SW switch alleviates the bottleneck caused by the centralized control of switching functions in large shared-memory switches. Decentralized switching functions enable the SW switch to operate in a pipeline fashion to enhance scalability and switching capacity compared with that of previously known classes of shared-memory switch architecture.     

A rapid and sensitive extractive spectrophotometric determination of copper(II) in pharmaceutical and environmental samples using benzildithiosemicarbazone.

Benzildithiosemicarbazone (BDTSC) is proposed as a sensitive and selective analytical reagent for the extractive spectrophotometric determination of copper(II). BDTSC reacts with copper(II) in the pH range 1.0-7.0 to form a yellowish complex. Beer's law is obeyed in the concentration range 0.5-0.4 microg cm(-3). The yellowish Cu(II)-BDTSC complex in chloroform shows a maximum absorbance at 380 nm, with molar absorptivity and Sandell's sensitivity values of 1.63 x 10(4) dm3 mol(-1) cm(-1) and 0.00389 microg cm(-2), respectively. A repetition of the method is checked by finding the relative standard deviation (RSD) (n = 10), which is 0.6%. The composition of the Cu(II)-BDTSC complex is established as 1:1 by slope analysis, molar ratio and Asmus' methods. An excellent linearity with a correlation coefficient value of 0.98 is obtained for the Cu(II)-BDTSC complex. The instability constant of the complex calculated from Edmond and Birnbaum's method is 7.70 x 10(-4) and that of Asmus' method is 7.66 x 10(-4), at room temperature. The method is successfully employed for the determination copper(II) in pharmaceutical and environmental samples. The reliability of the method is assured by analyzing the standard alloys (BCS 5g, 10g, 19e, 78, 32a, 207 and 179) and by inter-comparison of experimental values, using an atomic absorption spectrometer.