Identification of wild and farmed broadhead catfish ( Clarias macrocephalus Günther, 1864) based on morphometry,digestive indexes and flesh quality

Journal of Oceanology and Limnology - Wild and farmed fish generally differ in their nutritional composition. In this study, adult wild and farmed broadhead catfish ( Clarias macrocephalus...     

Damped least-squares inversion of confined aquifer pumping data based on singular value decomposition

An iterative method for calculating the transmissivity and storage coefficient from pumping test data for a confined aquifer is presented. The method optimizes the fit between the measured and the theoretical data (computed using the Theis equation) in the leastsquare sense. Unlike the existing schemes, this method employs the Levenberg-Marquardt method and the singular value decomposition technique resulting in a stable and rapidly convergent data inversion algorithm. The inverse procedure is initialized by an automatically created starting model derived using a novel technique that operates on the timederivative of the drawdown curve. An important feature of the algorithm is that all the computations are done in logarithmic space which effectively linearizes the pmblem. The proposed method has several advantages over the conventional iterative inversion algorithms because of the linearizing parameterizations at both the forward and inverse stages of the problem. Detailed derivations of the basic equations are provided to guide the potential users as well as applications to field data to demonstrate the usefulness of the proposed algorithm.     

Usage of chromite wastes as aggregate in foam concrete production

The rapidly developing mining sector in recent years has also brought environmental problems together. At the beginning of these problems are mine process wastes produced in high quantities from mines every year. The waste material at 90% and the concentrate chromite at 10% are obtained in the chromite ore enrichment plants. This significant amount of waste creates pollution in nature visually and physically. The aim of the study is to determine the advantages of using foamed concrete as a building material, to reduce the production cost of foamed concrete, to produce alternative solutions for rehabilitation, and to eliminate environmental pollution. The chromite enrichment wastes obtained from Fethiye, Köyce?iz, Denizli and Burdur regions were used as aggregates in the production of foamed concrete. In this study, compressive strength experiments were carried out according to TS EN 1354, thermal conductivity experiments were carried out according to TS EN 12664. As a result, it has been observed that chromite waste (dunite) can be used in the production of foamed concrete under certain conditions.     

Sorption characteristics of peat of Brunei Darussalam IV: equilibrium,thermodynamics and kinetics of adsorption of methylene blue and malachite green dyes from aqueous solution

Peat of Brunei Darussalam shows a great potential for the removal of methylene blue (MB) and malachite green (MG) dyes from aqueous solution. Carefully controlled batch experiments performed by changing one parameter at a time indicate that the optimum time periods of agitation and settling required for maximum removal of MB are 2.0 and 1.0 h, respectively, while these values for MG are 4.0 and 1.0 h, respectively. The optimum pH is determined to be the ambient value, and under the optimum conditions, 90 % removal of both dyes was determined under laboratory conditions. The equilibrium adsorption data analyzed for various isotherm models suggest that the Sips and Redlich–Peterson (R–P) models are valid for MB and MG, respectively. Further, thermodynamic studies show that the adsorption of both dyes on peat is spontaneous and endothermic. The adsorption capacities (q _max) of MB and MG dyes on peat are 0.45 and 0.31 mmol g^?1, respectively. Characterization of the surfaces of peat before and after treatment of dyes by SEM and FTIR provides conclusive evidence of adsorption of both dyes. Kinetics studies indicate that the adsorption of both MB and MG dyes is favored toward the pseudo-second-order model, with a little contribution of MG to the pseudo-first-order model. These results suggest that peat is a potential low-cost adsorbent for the removal of MB and MG dyes.