Properties and potential of formed cokes derived from two Turkish lignites by carbonization of binderless briquettes

Two high-sulphur Turkish lignites were briquetted at room temperature under pressures of 113 or 212 MPa and the briquettes were carbonized to 1158–1173 K over special heating cycles. The lower-rank lignite gave a formed coke of superior mechanical strength, lower porosity and higher sulphur content than typical blast furnace cokes. The formed coke produced from the higher-rank lignite briquettes had slightly poorer mechanical strength, lower porosity and much higher ash yield and sulphur content than conventional cokes. The products were considered attractive for use in non-ferrous metallurgy.     

Fermentation and oxygen transfer characteristics in recombinant human growth hormone production by Pichia pastoris in sorbitol batch and methanol fed‐batch operation

BACKGROUND: The influence of methanol feed rate on recombinant human growth hormone (rhGH) production by Pichia pastoris hGH‐Mut⁺ in medium containing sorbitol was investigated at three different specific growth rates (µ), namely, 0.02 (MS‐0.02), 0.03 (MS‐0.03), and 0.04 (MS‐0.04). RESULTS: Increasing methanol feed rate above MS‐0.03 did not affect sorbitol consumption, showing that µ = 0.03 h^?1 is a threshold limiting value, above which sorbitol utilization became independent of methanol feed rate. Moreover, when sorbitol was consumed, no further cell growth was observed. Increase in methanol feed rate triggered cell synthesis and the highest cell concentration was obtained at MS‐0.04 as 48 g L^?1 (t = 18 h); whereas, the highest rhGH production, 270 mg L^?1, was obtained at MS‐0.03 as a consequence of lower extracellular protease production and higher AOX activity (41 U g^?1 CDW). Oxygen uptake rate increased with increasing µ, having the maximum value, 76.6 mmol m^?3 s^?1, at MS‐0.04. K_La had a tendency to increase with µ, having a maximum value of 0.15 s^?1 at MS‐0.04 (t = 15 h). CONCLUSION: By considering rhGH concentration and oxygen transfer characteristics, the bioprocess can be improved by a two‐stage feeding strategy, operating at MS‐0.04 at the beginning of fermentation, and thereafter shifting to MS‐0.03. Copyright © 2009 Society of Chemical Industry     

Stochastic finite element analysis of a cable-stayed bridge system with varying material properties

Stochastic seismic finite element analysis of a cable-stayed bridge whose material properties are described by random fields is presented in this paper. The stochastic perturbation technique and Monte Carlo simulation (MCS) method are used in the analyses. A summary of MCS and perturbation based stochastic finite element dynamic analysis formulation of structural system is given. The Jindo Bridge, constructed in South Korea, is chosen as a numerical example. The Kocaeli earthquake in 1999 is considered as a ground motion. During the stochastic analysis, displacements and internal forces of the considered bridge are obtained from perturbation based stochastic finite element method (SFEM) and MCS method by changing elastic modulus and mass density as random variable. The efficiency and accuracy of the proposed SFEM algorithm are evaluated by comparison with results of MCS method. The results imply that perturbation based SFEM method gives close results to MCS method and it can be used instead of MCS method, especially, if computational cost is taken into consideration.     

Fatty acid profile and proximate composition of Pacific mullet (Mugil so‐iuy) caught in the Black Sea

This study demonstrates proximate composition and fatty acid profile of Pacific mullet caught in Turkey. The highest moisture and protein contents were observed with muscle tissues as 83.74 and 10.52%, while the highest fat and ash contents were attributed to female gonads as 11.80 and 0.94%, respectively, with a significant variation amongst months (P < 0.05). Significant variation (P < 0.05) usually occurred amongst months within the same sex for total saturated fatty acids ( ∑ SFA), monosaturated fatty acids ( ∑ MUFA), polyunsaturated fatty acids ( ∑ PUFA), eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) in muscle, although overall mean values between sexes were not found significant. Except for EPA, no variation observed for gonads while significant changes occurred (P < 0.05) with liver samples amongst months. Overall total values of ∑ SFA, ∑ MUFA, ∑ PUFA, DHA and EPA in muscle samples were 29.59, 29.26, 18.06 and 4.48%, respectively, while in gonads ranged as 30.26–33.23%, 35.17–37.47%, 11.87–14.88%, 4.38–5.34% and 3.02–5.02%. These FAs were 21.57–33.11%, 32.89–50.96%, 14.78–20.08%, 0.89–9.94% and 5.85–9.54% for liver, respectively. The results of this study showed that muscle and gonads of Pacific mullet were rich in n‐3 PUFA, especially, EPA, DHA, increasing the value of this species for human consumption.     

A new approach to eliminating EOG artifacts from the sleep EEG signals for the automatic sleep stage classification

Neural Computing and Applications - Interference between EEG and EOG signals has been studied heavily in clinical EEG signal processing applications. But, in automatic sleep stage classification...     

Preparation of polyacrylamide hydrogels at various charge densities by postmodification

In this study, first polyacrylamide hydrogels were synthesized by free‐radical crosslinking polymerization of acrylamide monomer with N,N′‐methylenebis(acrylamide) as a crosslinker in an aqueous solution at 22°C. Then, a series of hydrogels at various charge densities were prepared by partial hydrolysis of polyacrylamide precursors in a 0.1M sodium hydroxide solution at 60°C. The hydrolysis time was varied between 20 and 180 min. The chemical structures and internal morphologies of the hydrogels before and after alkaline hydrolysis were characterized with attenuated total reflectance/Fourier transform infrared and scanning electron microscopy measurements. The swelling ratio of the hydrolyzed hydrogels was measured in buffer solutions at various pHs. From differential curves of dQ_v/dpH versus pH (where Q_v is the equilibrium swelling ratio of the hydrogels), the volume phase transition pH of the hydrogels was found to be 4.33 ± 0.05, regardless of the charge density of the hydrogels. In water at 22°C, the hydrogels with greater charge density showed a more rapid swelling rate because of their higher porosity and hydrophilicity. Moreover, in buffer solutions with the pH changing from 9.0 to 2.0 at 22°C, the hydrogels with greater charge density also exhibited a more rapid deswelling rate than the hydrogels with less charge density. In conclusion, the postmodification method is a good way of preparing pH‐sensitive hydrogels with fast responsiveness. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

Improvement of anthocyanin content in the cv. Öküzgözü wines by using pectolytic enzymes

The effect of the addition of two commercial pectolytic enzymes on the anthocyanin and chemical composition of Öküzgözü wines was studied. A rapid HPLC-diode array detection (DAD) method was developed for the analysis of anthocyanins in wines. Direct injection of filtered wine samples followed by selective detection at 520 nm allowed quantitation of these compounds in red wines. Thirteen anthocyanin compounds were detected in wines and, addition of the two enzyme preparations improved the extraction of anthocyanins. Moreover, the wines treated with enzymes had higher values in total phenolics, tannins, and colour intensity than the control wines.     

Clinoptilolite-rich mineral as a novel carrier for the active constituents present in Ginkgo biloba leaf extract

The possible use of clinoptilolite-rich mineral as a novel carrier for the active constituents present in Ginkgo biloba leaf extract solutions was investigated. The flavonoid aglycone constituents were found to be selectively adsorbed on the clinoptilolite surface. The antioxidant activity determinations of the extract solutions were performed by the Trolox Equivalent Antioxidant Capacity (TEAC) assay. The antioxidant activity measurements performed for the Ginkgo leaf extract solutions showed decreasing antioxidant activities due to adsorption. The decrease in antioxidant activity was attributed to the adsorption of phenolic constituents on the clinoptilolite surface.     

Performance of Airyprime beam in turbulent atmosphere

Photonic Network Communications - In this paper, we present scintillation and bit error rate (BER) behavior of Airyprime beam in turbulent atmosphere. We use numerical setup random phase screen...