Laboratory Studies to Determine Suitable Chemicals to Improve Oil Recovery from Garzan Oil Field

Garzan oil field is located at the south east of Turkey. It is a mature oil field and the reservoir is fractured carbonate reservoir. After producing about 1% original oil in place (OOIP) reservoir pressure started to decline. Waterflooding was started in order to support reservoir pressure and also to enhance oil production in 1960. Waterflooding improved the oil recovery but after years of flooding water breakthrough at the production wells was observed. This increased the water/oil ratio at the production wells. In order to enhance oil recovery again different techniques were investigated. Chemical enhanced oil recovery (EOR) methods are gaining attention all over the world for oil recovery. Surfactant injection is an effective way for interfacial tension (IFT) reduction and wettability reversal. In this study, 31 different types of chemicals were studied to specify the effects on oil production. This paper presents solubility of surfactants in brine, IFT and contact angle measurements, imbibition tests, and lastly core flooding experiments. Most of the chemicals were incompatible with Garzan formation water, which has high divalent ion concentration. In this case, the usage of 2-propanol as co-surfactant yielded successful results for stability of the selected chemical solutions. The results of the wettability test indicated that both tested cationic and anionic surfactants altered the wettability of the carbonate rock from oil-wet to intermediate-wet. The maximum oil recovery by imbibition test was reached when core was exposed 1-ethly ionic liquid after imbibition in formation water. Also, after core flooding test, it is concluded that considerable amount of oil can be recovered from Garzan reservoir by waterflooding alone if adverse effects of natural fractures could be eliminated.     

Flexible poly(styrene-ethylene-butadiene-styrene) hybrid nanofibers for bioengineering and water filtration applications

Among the thermoplastic elastomers that play important roles in the polymer industry due to their superior properties, styrene-based species and polyurethane block copolymers are of great interest. Poly(styrene-ethylene-butadiene-styrene) (SEBS) as a triblock copolymer seems to have the potential to meet many demands in different applications due to various industrial requirements where durability, biocompatibility, breaking elongation, and interfacial adhesion are important. In this study, the SEBS triblock copolymer was functionalized with natural (Satureja hortensis, SH) and synthetic (nanopowder, TiO₂) agents to obtain composite nanofibers by electrospinning and electrospraying methods for use in biomedical and water filtration applications. The results were compared with thermoplastic polyurethane (TPU) composite nanofibers, which are commonly used in these fields. Here, functionalized SEBS nanofibers exhibited antibacterial effect while at the same time improving cell viability. In addition, because of successful water filtration by using the SEBS composite nanofibers, the material may have a good potential to be used comparably to TPU for the application.     

The impact of micro‐ and macroergonomics considerations on appropriate technology transfer decisions in developing countries: The case of Turkey

The research presented in this paper aims to support the decision process of appropriate technology transfer to industrially developing countries by improving a broader understanding of relationships between the key micro‐ and macroergonomics factors and the technology alternatives. The methodology involves knowledge acquisition, identifying and categorizing a holistic set of key criteria about technology transfer with respect to ergonomics. This work attempts briefly to identify factors affecting the success of technology transfer in order to reduce the potential of incompatibilities with respect to micro‐ and macroergonomics and to optimize the decision process of managers. The objective of the decision model, based on the analytic hierarchy process (AHP), determines the global priority weights for different technology alternatives and examines the critical factors and benefits, which affect the appropriateness of technology transfer. © 2007 Wiley Periodicals, Inc. Hum Factors Man 17: 1–19, 2007.     

Accurate Receptor-Ligand Binding Free Energies from Fast QM Conformational Chemical Space Sampling

Small molecule receptor-binding is dominated by weak, non-covalent interactions such as van-der-Waals hydrogen bonding or electrostatics. Calculating these non-covalent ligand-receptor interactions is a challenge to computational means in terms of accuracy and efficacy since the ligand may bind in a number of thermally accessible conformations. The conformational rotamer ensemble sampling tool (CREST) uses an iterative scheme to efficiently sample the conformational space and calculates energies using the semi-empirical ‘Geometry, Frequency, Noncovalent, eXtended Tight Binding’ (GFN2-xTB) method. This combined approach is applied to blind predictions of the modes and free energies of binding for a set of 10 drug molecule ligands to the cucurbit[n]urils CB[8] receptor from the recent ‘Statistical Assessment of the Modeling of Proteins and Ligands’ (SAMPL) challenge including morphine, hydromorphine, cocaine, fentanyl, and ketamine. For each system, the conformational space was sufficiently sampled for the free ligand and the ligand-receptor complexes using the quantum chemical Hamiltonian. A multitude of structures makes up the final conformer-rotamer ensemble, for which then free energies of binding are calculated. For those large and complex molecules, the results are in good agreement with experimental values with a mean error of 3 kcal/mol. The GFN2-xTB energies of binding are validated by advanced density functional theory calculations and found to be in good agreement. The efficacy of the automated QM sampling workflow allows the extension towards other complex molecular interaction scenarios.     

Influence of the cross‐sectional shape on the structure and properties of polyester fibers

The effects of the fiber cross‐sectional shape on the structure and properties of polyester fibers were investigated. Fully drawn yarn (FDY) polyester fibers (167 dtex and 48 filaments) were produced under the same spinning conditions used in a spinning plant. The only difference between the fibers was their cross‐sectional shapes. Four different cross‐sectional shapes were chosen for the experimental work: round, hollow‐round, trilobal, and hollow‐trilobal. The crystallinity and values of the maximum stress, maximum strain, modulus, yield stress, shrinkage in boiling water, and unevenness of the fibers were determined. The difference in the cross‐sectional shapes influenced the modulus, maximum strain, yield stress, and shrinkage in boiling water. No effects on the crystallinity and maximum stress were observed. The results suggested that the hollow fibers had higher amorphous orientation than the full fibers. The hollow‐round fiber had the highest unevenness value. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103: 2615–2621, 2007     

Speech Separation Methodology for Hearing Aid

In the design of hearing aids (HA), the real-time speech-enhancement is done. The digital hearing aids should provide high signal-to-noise ratio, gain improvement and should eliminate feedback. In generic hearing aids the performance towards different frequencies varies and non uniform. Existing noise cancellation and speech separation methods drops the voice magnitude under the noise environment. The performance of the HA for frequency response is non uniform. Existing noise suppression methods reduce the required signal strength also. So, the performance of uniform sub band analysis is poor when hearing aid is concern. In this paper, a speech separation method using Non-negative Matrix Factorization (NMF) algorithm is proposed for wavelet decomposition. The Proposed non-uniform filter-bank was validated by parameters like band power, Signal-to-noise ratio (SNR), Mean Square Error (MSE), Signal to Noise and Distortion Ratio (SINAD), Spurious-free dynamic range (SFDR), error and time. The speech recordings before and after separation was evaluated for quality using objective speech quality measures International Telecommunication Union -Telecommunication standard ITU-T P.862.     

Cancer patients psychological adjustment and perception of illness: cultural differences between Belgium and Turkey

Little is known about cultural differences in psychological adjustment and perception of illness (PI) during medical procedures in general and radiotherapy in particular. This study compares a Turkish (TP) and a French speaking Belgian (BP) population. A group of 296 consecutive patients attending the radiotherapy clinic of Institut Jules Bordet, Brussels, (n = 172) and Oncology Institute, Capa-Istanbul, (n = 124) were interviewed and assessed by a symptom checklist, the SCL-90-R, at the beginning and at the end of the radiotherapy. PI, derived from a semi-structured interview, was assessed at the beginning of radiotherapy by a five-point observer-rating scale derived from the Omega Vulnerability Rating Scale. Differences in SCL-90-R scores, taking into account country, age, gender, level of education and PI as potential explanatory variables, have been tested by a multivariate analysis of variance with a design of repeated measures using the SCL-90-R scores as dependent variables. Mainly a time effect and a country effect have been found. Some interactions between both effects have also been found. Globally, all the SCL-90-R scores decrease between the beginning and the end of the radiotherapy. The effect of country is noticeable for most of the SCL-90-R components, with higher scores in the BP, except for the positive symptom total score where the TP showed higher scores. The interaction between country and time is not significant, the scores of both the BP and TP decreasing over time, except for somatization scores (P < 0.001) where the scores of the BP were stable over time while the scores of the TP decreased considerably, and for paranoid ideation scores (P = 0.001) where the scores of the BP decreased while the scores of the TP increased. Results showed a higher rate of correct perception in the BP compared to the TP (P = 0.0001). A PI effect has been found for somatization (P = 0.02), anxiety (P = 0.01) and Global Severity Index scores (P = 0.05), with higher mean scores for the "correct perception" category. No interaction with time was found. A significant interaction effect between country and PI has been found for anxiety scores with higher scores in the correct perception category in the BP and in the "denial of implications" category in the TP (P < 0.001). Results highlight cultural differences in psychological adjustment and/or in the responses to self-report questionnaires: greater weight was given to items by the BP, more numerous items were scored by the TP, and greater weight was given to the somatization subscale compared to the psychological subscales by the TP. This study suggests that psychosocial distress is expressed differently in Belgium and Turkey, where patients express mostly somatic complaints. Finally PI, a culture-dependent factor, appears to influence psychological adjustment very differently, a correct perception of illness leading to more anxiety in the BP compared to the TP.     

Leveraging technological knowledge transfer by using fuzzy linear programming technique for multiattribute group decision making with fuzzy decision variables

Despite the importance of knowledge transfer for firms involved in foreign direct investment activities, this area has not received appropriate attention from the perspectives of both the knowledge transferor (i.e., MNC parent) and the knowledge recipient. To fill in the gap in the current literature we propose a model to understand the links between criteria complicating the transfer of knowledge and preferences that the company has to focus. This model is based on both the existing literature as well as views of company representatives and provides a useful methodology for identifying decision making problems on the transfer of knowledge. In this paper, we investigate the fuzzy linear programming technique (FLP) to analyze these links and for multiple attribute group decision making (MAGDM) problems with preference information on criteria. To reflect the decision maker’s subjective preference information and to determine the weight vector of attributes, the technique for order preference by similarity to ideal solution (TOPSIS) developed by Hwang and Yoon (1995) and the linear programming technique for multidimensional analysis of preference (LINMAP) developed by Sirinivasan and Shocker (Psychometrica 38:337–369, 1973) are used.