An enhanced symbiosis organisms search algorithm: an empirical study

Many nature-inspired optimization algorithms have recently been proposed to solve difficult optimization problems where the mathematical gradient-based approaches could not be used. However, those approaches were often not tested on a proper set of problems. Moreover, statistical tests are sometimes not used to validate the conclusions. Therefore, empirical analyses of such approaches are needed. In this paper, a very recent nature-inspired approach, symbiosis organisms search (SOS), is investigated. A set of unbiased and characteristically different problems are used to study the performance of SOS. In addition, a comparison with some recent optimization methods is conducted. Then, the effect of SOS only parameter, eco_size, is studied, and the use of different random distributions is also explored. Finally, three simple SOS variants are proposed and compared to the original SOS. Conclusions are validated using nonparametric statistical tests.

     

Ultrasonic absorption and visco-relaxation study of poly(vinyl alcohol) aqueous solution. (A method for the determination of molecular weight)

Ultrasonic absorption and velocity measurements are reported on aqueous solutions of poly(vinyl alcohol) (PV-OH) of different molecular weights and concentrations obtained using a pulsed ultrasonic apparatus operating at 2 MHz and 303 K. The variations in these parameters as a function of concentration are interpreted in terms of changes in the magnitude of the contribution due to relaxation of the backbone and of the side chain acetyl groups. The results show an increase in velocity, density and viscosity with increase in molecular weight and concentration of PV-OH. In contrast the attenuation values decrease with increase in molecular weight. This suggests that interaction is occurring between PV-OH and water molecules. Deviation of the variation of the attenuation with concentration from the ‘ideal’ dilute solution behaviour at high concentration is ascribed to the effects of polymer-polymer interaction. The magnitude of the volume change associated with polymer-solvent interactions is estimated and discussed. A mathematical equation correlating the relaxation amplitude and the molecular weight of the polymer is suggested. This approach was applied to the calculation of the molecular weight of four unknown samples of PV-OH from their measured relaxation amplitudes. The results obtained agree well with those obtained from osmometry.     

Physiochemical characterizations of hydroxyapatite extracted from bovine bones by three different methods: Extraction of biologically desirable HAp

In the present study, subcritical water and alkaline hydrolysis methods are proposed methodologies for extraction of natural hydroxyapatite bioceramic from bovine bone. In these processes, the bovine bones powder were treated by high pressure water at 250 °C for 1 h and 25% (wt) sodium hydroxide at 250 °C for 5 h, respectively. Also the conventional calcination methodology has been utilized as well (T = 850 °C for 1 h). The obtained apatites from the three treatment processes have been characterized by powder X-ray diffraction analysis (XRD), Fourier transform infrared spectroscopy (FT IR), transmission electron microscopy (TEM), thermal gravimetric analysis (TGA), electron scanning microscopy (SEM), energy dispersive X-ray analysis (EDX) and field emission scanning electron microscopy (FE SEM). FT IR and XRD results affirmed that both the proposed methods and the traditional one can eliminate the collagen and other organic materials present in the bovine bones. The physiochemical characterizations for the obtained apatites have proved that the subcritical water and the alkaline hydrolysis relatively preserve the carbonate content present in the biological apatite, so they yield carbonated hydroxyapatite which is medically preferable. While, the thermal process produces almost hydroxyapatite carbonate-free.     

Structural,electronic, and optical properties of orthorhombic and triclinic BiNbO4 determined via DFT calculations

We performed ab initio calculations using the FPLAW method with the local density approximation (LDA) implemented in the WIEN2 k code for the orthorhombic (α) and triclinic (β) phases of BiNbO₄. The modified Becke–Johnson exchange potential (mBJ)-LDA approach was also used to improve the electronic properties. The lattice constants calculated for both structures using the LDA are in good agreement with the experimental values. For the band structure calculations, the mBJ-LDA approach provides reasonable agreement for the band gap value compared with the LDA. The estimated (mBJ)-LDA band gap values are 2.89 eV (3.73 eV) and 2.62 eV (3.15 eV) for the α and β phases of BiNbO₄, respectively. Significant optical anisotropy is clearly observed in the visible-light region. We also calculated and evaluated the electron energy loss spectrum for BiNbO₄. This work provides the first quantitative theoretical prediction of optical properties and electron energy loss spectra for both the orthorhombic and triclinic phases of BiNbO₄.     

A study of the thermodynamics and phase relationships of the Fe−Co−S−O quaternary system

The oxygen potentials of several three- and two-phase equilibria in the Fe−Co−S−O quaternary system were measured atP _SO2=1, 0.1, and 0.01 atm over wide temperature ranges. The measurements were carried out using a solid oxide electrolyte emf technique. The equilibria measured are sp+ε+δ, s+ε+ξ, sp+ξ+η, and sp+δ. The symbols sp, ε, δ, ξ, and η denote the spinel, monoxide, monosulfide, metal sulfate, and Fe₂O₃ phases, respectively. Compositions for several of the equilibrated phases were measured using electron probe microanalysis. The present results and literature data for the constituent ternary systems were used to obtain thermochemical solution parameters for the sp, ε, δ and ξ solid solution phases. The calculated potential-composition stability diagrams for SO₂ pressures of 1, 0.1, and 0.01 atm at 973, 1023, and 1073 K, respectively, are in good agreement with the experimental results. OMRAN A. MUSBAH, formerly Research Associate at the University of Wisconsin-Madison     

The trace spectra of polynomial bases for $${\mathbb{F}}_{2^{n}}$$

In this paper we study the trace spectra of polynomial bases for over . Shparlinski showed that there exists a polynomial basis having O(log n) elements of trace one. Here we show that for every t ≤ n, there exists a polynomial basis having t + O(log n) elements of trace one. We also study consequences of our results to the existence of irreducible polynomials of certain weights.     

Clinical, bacteriological, and histopathological study of toxic puerperal metritis in Iraqi buffalo

Data were collected from 42 buffalo with toxic puerperal metritis in 2 large herds, with a history of dystocia, prolapse, and retained placenta. All buffalo were subjected to detailed clinical examination including external inspection, vaginoscopy, and transrectal palpation of the cervix, uterus, and ovaries. Swabs for bacteriology and biopsies for histopathology were collected from the uterine lumen from each cow. Character, odor, and estimation of polymorphonuclear cells of the vaginal mucus were scored. Blood samples were collected from cows for creatine kinase and aspartate amino-transferase measurement. The most predisposing factor causing toxic puerperal metritis was retained placenta (52.4%), and the most prevalent bacteria in uterine lumen were Escherichia coli, Arcanobacterium pyogenes, Staphylococcus aureus, and Fusobacterium necrophorum (18.5, 16.7, 13.0, and 9.3%, respectively). High levels of polymorphonuclear cells were observed in buffalo infected with A. pyogenes and gram-negative anaerobic bacteria (62.1 and 76.4%). A high prevalence of gram-negative anaerobes was isolated from uteri harboring A. pyogenes (13.0%). Buffalo with toxic puerperal metritis had significantly higher creatine kinase and aspartate aminotransferase activities than controls (499.2 ± 23.9 and 208.3 ± 11.3 vs. 242.7 ± 12.9 and 166.8 ± 11.5 U/L, respectively). In a conclusion, gram-negative anaerobes and other facultative pathogens including A. pyogenes were important pathogens that cause severe uterine inflammation.     

Discharge estimation in compound channels with fixed and mobile bed

Two-dimensional (2-D) formulae for estimating discharge capacity of straight compound channels are reviewed and applied to overbank flows in straight fixed and mobile bed compound channels. The predictive capabilities of these formulae were evaluated using experimental data obtained from the small-scale University of Birmingham channel. Full details of these data and key references may be found at the following www.flowdata.bham.ac.uk (university website). 2-D formulae generally account for bed shear, lateral shear, and secondary flow effects via 3 coefficients f, λ and Γ In this paper, the secondary flow term (Γ) used within the 2-D methods analysed here is ignored in all applications. Two different 2-D formulae almost give practically the same results for the same data when the secondary flow term is ignored. For overall test cases, the value of dimensionless eddy viscosity λ used in 2-D formulae was kept at 0·13 as recommended for open channels. 2-D formulae gave good predictions for most of the data sets studied in comparison with the traditional 1-D methods, namely the Single Channel Method (SCM) and the Divided Channel Method (DCM). The accuracy of predictions of 2-D formulae was increased by calibrating of λ value where the calibration was needed. For overall data, the average errors for each method were Lateral Division Methods (LDMs), with λ value of 0·13, 2·8%, DCM 14·3% and SCM −26·8%. The average error was 0·5% for LDMs with the calibrated values of λ