Performance evaluation of a submerged membrane bioreactor for the treatment of brackish oil and natural gas field produced water

Produced water, which is co-produced during oil and gas manufacturing, represents one of the largest sources of oily wastewaters. Therefore, treatment of this produced water may improve the economic viability and lead to a new source of water for beneficial use. In this study a submerged hollow fiber membrane bioreactor (MBR) has been studied experimentally for the treatment of brackish oil and natural gas field produced water. This type of wastewater is also characterized with relatively moderate to high amount of salt, oil and total petroleum hydrocarbons (TPH). However, the bacteria which are growing in conventional activated sludge and MBR cannot survive at these strict conditions, therefore acclimation of the bacteria is of vital importance. The performance of the biological system, membrane permeability, the rate and extent of TPH biodegradability have been investigated under different sludge age and F/M ratios. The results obtained by gas chromatography analyses showed that the MBR system could be very effective in the removal of TPH from produced water and a significant improvement in the effluent quality was achieved.     

Seismic microzonation of the historic peninsula of İstanbul

In this study, the geological and geotechnical conditions of old Istanbul (Fatih and Eminönü provinces) were investigated in detail and a seismic microzonation study was undertaken for this historical peninsula, which is the site of many ancient structures. Dynamic site response, liquefaction potential and slope stability analyses were carried out, based on field and laboratory tests and earthquake time histories computed with respect to probabilities of exceedance of 10 and 40% in 50 years. The output data obtained from the analyses were evaluated by GIS techniques, and ground shaking, liquefaction susceptibility and landslide hazard maps were prepared.     

Reliability analysis of the complex mode indicator function and Hilbert Transform techniques for operational modal analysis

This study presents application of the CMIF and the Hilbert Transform techniques onto simulated response data obtained using a numerical model of a typical school building from Turkey. White noise is added to the data in order to achieve a noise to signal ratio of 5%. 100 Monte Carlo analysis sequences are carried out and the modal parameters (the frequencies, the mode shapes and the damping ratios) are identified at each Monte Carlo run for both techniques. The results are compared with the identifications obtained from the simulated data using stochastic subspace based system identification technique. The overall results of the study show that the mode shapes are clearly identified the best by using the CMIF technique. The damping ratios are estimated better by using the stochastic subspace based system identification technique whereas the frequencies are best determined by the CMIF. The results also show that both the CMIF and the Hilbert Transform techniques are sensitive to the type of window used as well as the averaging and the decimation process. It is apparent that the CMIF technique is as robust as the frequently used stochastic subspace based system identification technique and can be confidently used for modal parameter estimation of stiff low to mid rise reinforced concrete structures.     

Automation of the stabilization diagrams for subspace based system identification

For the continuous real-time monitoring of structures, the realization of a fully automatic real time system identification without any human intervention is the most crucial step. In this study, a new technique for the automation of the stability diagrams is developed that uses the modal phase collinearity (MPC) in order to quantify the spatial consistency of the identification results. In the new technique, the stabilization diagram is modeled as a histogram composed of overlapping bins. New strategies for the multiple occurrence of poles in the neighboring bins and double poles within a bin are developed. A new cluster validity index is proposed which can solve the problem caused by the scale of measurements and which can be directly calculated from non-normalized data. The threshold limits are defined for the proposed index. The results of the study show that the automation of the pole selection process from the stabilization diagrams is successfully realized. It is also shown that for local modes, the MPC value will be substantially smaller as compared to the global modes and can be used as a quick, efficient and powerful measure of global versus local response behavior.     

Gap junctional intercellular communication of primary and asbestos-associated malignant human mesothelial cells

We examined gap junctional intercellular communication (GJIC) of primary human mesothelial cells and cell lines of asbestos-associated human pleural mesotheliomas, and the effect of asbestos and other mineral fibres on these cells. In homologous cultures, the GJIC capacity of six out of seven tumour cell lines was markedly less than for primary mesothelial cells. This defect in GJIC appeared not to be at the expression level of mRNA and protein of the gene encoding the 43 kDa gap junction protein. In heterologous cocultures of tumour cells and primary mesothelial cells, however, 80-90% of the tumour cell/normal cell contacts were functional. Exposure of primary mesothelial cells to TPA, a phorbol ester tumour promoter, resulted in marked inhibition of GJIC, being an action common to numerous tumour promoters. Such an effect though was not observed with the carcinogenic mesothelioma-inducing mineral fibres chrysotile and amosite, neither with glass wool. These results suggest that a permanent defect in GJIC capacity is a common feature of human mesothelioma cells, but how mineral fibres are involved in the process of mesotheliomagenesis is still unclear.     

Various types of suprameatal spines and depressions in the human temporal bone

Since it covers the lateral wall of the mastoid air system, the suprameatal triangle is of importance to otologic surgeons during mastoidectomy. Because of this clinical importance, topographic anatomy of the suprameatal spine and depression was studied on Anatolian skulls. In all, 363 male and 231 female skulls were studied. The most prevalent type of suprameatal spine resembled a crest and was found in both sexes on the right (77.6%) and left (80%) sides. The absence of a suprameatal depression was significantly higher in females (right 9.1%; left 8.7%) than in males (right 1.7%; left 2.5%). Suprameatal depressions were mostly shallow in female subjects, but were mostly observed in males to be at a medium depth or deep.     

Heavy metal levels in leafy vegetables and some selected fruits

The aim of this study was to determine the levels of Cu, Zn, Fe, Pb and Cd in various fruits (tomato, cherry, grape, strawberry) and vegetables (parsley, onion, lettuce, garlic, nettle, peppermint, rocket, spinach, dill, broad bean, chard, purslane, grapevine leaves) grown in Manisa region. Flame and Graphite Furnace Atomic absorption spectrometry was used to estimate and evaluate the levels of these metals. Detected levels ranged from 0.56 to 329.7, 0.01 to 5.67, 0.26 to 30.68, 0.001 to 0.97 and 0 to 0.06 μg/g for Fe, Cu, Zn, Pb and Cd, respectively. While the highest mean levels of Cu and Zn were detected in grapevine leaves, the lowest mean levels of Fe and Pb were detected in nettle. Cd was not detected in most of the fruits and vegetables studied. The estimated daily intakes of Cu, Zn, Fe, Pb and Cd through fruits and vegetables were found to be below the maximum tolerable levels recommended by FAO/WHO. The element concentrations of fruits and vegetables analyzed in this study were within safety baseline levels for human consumption.     

Predominant yeasts in the sourdoughs collected from some parts of Turkey

In the present study, a total of eight sourdough samples were collected from three different bakeries at two different times in Turkey. Also, laboratory-scale sourdough production was conducted by daily back-slopping for 7 days. Microbiological and chemical properties of the sourdoughs were investigated. Yeast species in the sourdoughs were identified by subjecting all presumptive yeast cultures to internal transcribed spacer region amplification of the 5.8S rRNA gene, restriction fragment length polymorphism analysis using Hae III, Hha I, and Hinf I endonucleases, and sequence analysis of the D1/D2 domain of the 26S rDNA gene. A total of seven profiles were determined according to the restriction fragments. Totally, 148 yeast isolates were identified at the species level (≥400 bp , 99% identity) as Saccharomyces cerevisiae (106), Kazachstania bulderi (11), Pichia fermentans (nine), Pichia membranifaciens (eight), Kazachstania servazzii (seven), Kazachstania unispora (four), and Hanseniaspora valbyensis (three). Although collected sourdoughs were produced without using baker's yeast, S. cerevisiae was the most frequently isolated yeast species. This can be related to the contamination of the bakery environment with commercial baker's yeast during the production of other bakery products. The pH and acidity levels of the collected sourdough samples ranged from 3.71 to 3.96 and 6.78 to 23.93 mL 0.1 N NaOH/10 g dough, respectively. Mean values of the content of maltose + sucrose, glucose, fructose, lactic acid, and acetic acid were 2.43, 1.57, 2.67, 7.30, and 1.40 g/kg, respectively. Due to the artisan and region-dependent handling of the sourdough, different biochemical patterns were observed among the collected samples.