High-rate sulphidogenic fluidised-bed treatment of metal-containing wastewater at high temperature.

The applicability of fluidised-bed reactor (FBR) based sulphate reducing bioprocess was investigated for the treatment of iron containing (40-90 mg/L) acidic wastewater at 65 degrees C. The FBR was inoculated with sulphate-reducing bacteria (SRB) originally enriched from a hot mining environment. Ethanol or acetate was supplemented as carbon and electron source for the SRB. A rapid startup with 99.9, 46 and 29% ethanol, sulphate and acetate removals, in respective order, was observed even after 6 days. Iron was almost completely removed with a rate of 90 mg/L.d. The feed pH was decreased gradually from its initial value of 6 to around 3.7 during 100 days of operation. The wastewater pH of 4.3-4.4 was neutralised by the alkalinity produced in acetate oxidation and the average effluent pH was 7.8 +/- 0.8. Although ethanol removal was complete, acetate accumulated. Later the FBR was fed with acetate only. Although acetate was present in the reactor for 295 days, its oxidation rates did not improve, which may be due to low growth rate and poor attachment ability of acetate oxidising SRB. Hence, the oxidation of acetate is the rate limiting step in the sulphidogenic ethanol oxidation by the thermophilic SRB.     

Combinatorial Immunophenotyping of Cell Populations with an Electronic Antibody Microarray

Immunophenotyping is widely used to characterize cell populations in basic research and to diagnose diseases from surface biomarkers in the clinic. This process usually requires complex instruments such as flow cytometers or fluorescence microscopes, which are typically housed in centralized laboratories. Microfluidics are combined with an integrated electrical sensor network to create an antibody microarray for label‐free cell immunophenotyping against multiple antigens. The device works by fractionating the sample via capturing target subpopulations in an array of microfluidic chambers functionalized against different antigens and by electrically quantifying the cell capture statistics through a network of code‐multiplexed electrical sensors. Through a combinatorial arrangement of antibody sequences along different microfluidic paths, the device can measure the prevalence of different cell subpopulations in a sample from computational analysis of the electrical output signal. The device performance is characterized by analyzing heterogeneous samples of mixed tumor cell populations and then the technique is applied to determine leukocyte subpopulations in blood samples and the results are validated against complete blood cell count and flow cytometry results. Label‐free immunophenotyping of cell populations against multiple targets on a disposable electronic chip presents opportunities in global health and telemedicine applications for cell‐based diagnostics and health monitoring.     

Sulfidogenic fluidized-bed treatment of metal-containing wastewater at 8 and 65 degrees C temperatures is limited by acetate oxidation

Acetate utilization in sulfidogenic fluidized-bed reactors (FBRs) was investigated for the treatment of iron containing wastewater at low (8 degrees C) and high (65 degrees C) temperatures. The FBRs operated at low and high temperatures were inoculated with cultures of sulfate-reducing bacteria (SRB) originally enriched from arctic and hot mining environments, respectively. Acetate was not utilized as a carbon and electron source for SRB at 8 degrees C. With ethanol, hydrogen sulfide was produced from ethanol to acetate oxidation, which precipitated the iron. Then, several attempts were made to obtain acetate oxidation at 8 degrees C. Inoculation of two different low temperature enrichments and operating the FBR for a long period of time (321 days) did not result in enrichment of acetate oxidizing SRB. Due to the absence of acetate oxidation at 8 degrees C, external alkalinity addition was required to keep the pH neutral. At 65 degrees C, average acetate and sulfate removals were 52+/-12% and 24+/-8% at 670 mg/Ld acetate and 1500 mg/Ld sulfate loadings, respectively. The produced alkalinity from acetate oxidation increased the pH from 6.4 to around 7.5 and electron flow to sulfate reduction averaged 65%. Denaturing gradient gel electrophoresis (DGGE) analysis of 16S rRNA genes showed quite stable SRB community at 8 degrees C, whereas, at 65 degrees C SRB community was dynamic. In the FBRs, Desulfomicrobium apsheronum and Desulfosporosinus sp. at 8 degrees C and Desulfotomaculum sp. at 65 degrees C were detected.     

Microstructure and properties of Fe–Al intermetallic coatings on the low carbon steel synthesized by mechanical alloying

Fe–Al coating was obtained on low carbon steel substrates using mechanical alloying and subsequent heat treatment. Light optical microscopy and a scanning electron microscope equipped with energy dispersive spectroscopy were used to conduct the microstructure characterization. Mechanical properties of the coatings were evaluated by microhardness measurements and wear tests. The corrosion behavior was determined by potentiodynamic polarization measurements in 3.5 % NaCl solution. The results of the mechanical and corrosion tests showed that the hardness and wear resistance of the coatings decreased with increasing the milling time, while increase in the milling time resulted in a significant increase in the thickness, porosity level, and corrosion resistance.     

Effects of wheat maturation stage and cooking method on dietary fiber and phytic acid contents of firik, a wheat-based local food.

Samples of two durum wheat cultivars (cvs. Duraking and Ege 88) at different maturation stages (13, 16, 19, 22, 25 days post anthesis) were processed into firik (a wheat-based specialty food) using two different cooking methods: roasting (scorching) on flames and boiling at atmospheric pressure. Both the acid detergent and neutral detergent fiber contents of the firiks produced from two durum wheat samples decreased significantly (p < 0.01) with maturation. Total P contents of the firiks of both cultivars produced by both methods showed a significant downward trend within the period of maturation while their phytic acid contents showed a significant upward trend (p < 0.01). It was possible to obtain a reduced phytic acid, high fiber product from the wheats harvested at early stages of maturation (13 and 16 days after anthesis).     

Estimation of real GDP and unrecorded economy in Turkey based on environmental data

This paper estimates the real gross domestic product (GDP) and unrecorded economy for Turkey using the Kalman filter technique. Using different tests, most of the research articles on energy policy investigate the causal relationship between energy consumption and GDP for different countries. On the other hand, other studies on climate change try to show the effects of both energy consumption and GDP on carbon dioxide (CO₂) emission. Since the unreported economy has an important weight in developing countries where the recorded (or official) GDP suffers from considerable measurement problems, investigation of the relationship between the recorded GDP and energy consumption may lead to biased results. In this paper, the economic variables (GDP, country population) as well as environmental variables (CO₂ emission, forest area) are used in order to estimate GDP, which is an unobserved variable in our model. The results clearly indicate that: first, the true GDP in Turkey, that our model estimates, is higher than the observed (recorded) GDP in the whole period of observation (1973–2003) and the size of unrecorded economy varies between 12 and 30 percent of the observed GDP; second, the gap between the true GDP and the observed GDP has an increasing trend; third, if the change in GDP per primary energy supply is smaller than the change in CO₂ per primary energy supply, then there may exist unrecorded economy.     

Simulation optimization for revenue management of airlines with cancellations and overbooking

This paper develops a model-free simulation-based optimization model to solve a seat-allocation problem arising in airlines. The model is designed to accommodate a number of realistic assumptions for real-world airline systems—in particular, allowing cancellations of tickets by passengers and overbooking of planes by carriers. The simulation–optimization model developed here can be used to solve both single-leg problems and multi-leg or network problems. A model-free simulation–optimization approach only requires a discrete-event simulator of the system along with a numerical optimization method such as a gradient-ascent technique or a meta-heuristic. In this sense, it is relatively “easy” because alternative models such as dynamic programming or model-based gradient-ascent usually require more mathematically involved frameworks. Also, existing simulation-based approaches in the literature, unlike the one presented here, fail to capture the dynamics of cancellations and overbooking in their models. Empirical tests conducted with our approach demonstrate that it can produce robust solutions which provide revenue improvements over heuristics used in the industry, namely, EMSR (Expected Marginal Seat Revenue) for single-leg problems and DAVN (Displacement Adjusted Virtual Nesting) for networks.     

CONTROLS ON FRACTURE FLOW POTENTIAL IN A TIGHT CARBONATE RESERVOIR: SAYINDERE FORMATION (CAMPANIAN), WEST ADIYAMAN BASIN,SE TURKEY

Identifying controls on the permeability of fluid‐conductive fractures is critical in tight reservoirs, but this is challenging in tectonically complex regions such as foothills belts where there may have been multiple stages of deformation and fracturing. Fracture permeability depends on fracture aperture and connectivity, both of which are affected by tectonism and cementation. Among the many factors that control the cementation history, oil charging may play an important role. Important challenges in studies of fractured reservoirs in tectonically complex regions include determining the timing (and intensity) of fracturing events relative to that of the oil charge, verifying the presence of matrix storage, and establishing the fracture cementation history. This paper reports on a comparative fracture study of four small‐scale oilfields in the west Ad?yaman Basin, located within the foothills belt of the Tauride suture zone in SE Turkey. Here the tight reservoir carbonates of the Say?ndere Formation (Campanian) were subjected to repeated phases of structural deformation. Major deformation phases took place in Campanian and Maastrichtian times, before oil charging into the reservoir began in the Eocene; and in the Late Eocene – Oligocene and Late Miocene, after the oil charge. Fractures that were generated before oil emplacement appear to have been cemented or partially cemented by calcite as indicated by cross‐cutting cemented fractures on borehole images. Partially‐cemented fractures in cores are oil‐stained with cement‐lined walls, suggesting cementation began before oil emplacement but was not completed. Image logs and cores also show the presence of clean, open fractures with no cement present on the walls. These open fractures cut across the cemented or partially‐cemented fractures, and are in general related to Late Miocene compressional folding. Open fracture density is correlated to Late Miocene fold curvature and asymmetry in the four oilfields studied. Of these fields, the ?ambayat structure is the tightest and most asymmetric anticline and hence has the maximum open fracture density; this field also has the highest oil potential. Although the available data is not sufficient to evaluate the effects of oil charging on fracture cementation definitively, the observations are consistent with a model that oil charge into the fractured Say?ndere Formation carbonates inhibited or slowed calcite cementation. Hence fracturing of a carbonate reservoir after oil emplacement may significantly enhance the fracture permeability, and may even render a tight reservoir prospective.     

Yarn twist measurement using digital imaging

Digital image analysis techniques in the spatial and frequency domains for twist measurement of yarns are described. A spatial technique is developed to extract the twist angle through the analysis of the yarn core image. Then, a Fourier transformation technique is applied to yarn images to measure the orientation of the fibre on the yarn surface. Finally, a hybrid method that incorporates frequency domain filtering prior to spatial analysis is proposed. The trials show that spatial analysis is a fast method and can successfully predict the twist in the yarn. Fourier transformation technique is quite sensitive to the protruding fibres obstructing the yarn surface, which may result in measurements having high variations. For yarns having little amount of hairs protruding from the core, the results agreed reasonably well with actual twist levels. Frequency domain filtering in conjunction with the spatial analysis of the yarn surface is found to be superior in terms of accuracy. The twist values calculated using the more reliable diameter measurements with back-lit images together with twist angles from the front-lit images are found to be more accurate when compared with the actual values.