Optimization of downhole pump setting depths in liquid-dominated geothermal systems: A case study on the Balcova-Narlidere field,Turkey

Downhole pumps are being used increasingly more often in low-enthalpy geothermal wells. The depth at which these pumps are installed depends on the physical and chemical characteristics of the geothermal fluid, the production flow rate, and the reservoir pressure and permeability. In this study we have investigated the factors affecting pump setting depths in low-temperature, liquid-dominated geothermal systems and defined the relationship between flow rate and pressure drawdown based on multi-rate test results. The methodology proposed was applied to the Balcova-Narlidere geothermal field, Turkey. It was found that the most important parameters for determining the capacity and setting depth of a downhole pump were flow performance, non-condensable gas concentration, and temperature. The implementation of the methodology is illustrated.     

Mechanical behaviour of SiC fibre-reinforced titanium/titanium aluminide hybrid composites

The viability of developing an SiC fibre-reinforced titanium/titanium aluminide hybrid matrix composite was explored. The hybrid composites are expected to be used at temperatures beyond those attainable in conventional titanium matrix composites while improving the damage tolerance of the titanium aluminide matrix composites. The room-temperature mechanical characteristics studied were tensile strength, fracture toughness, low-cycle fatigue life and fatigue crack growth rate. The mechanisms of damage initiation and propagation under various loading conditions were also characterized. The directions for developing a satisfactory composite with hybrid titanium/titanium aluminide matrix are also addressed.     

Synthesis and characterization of novel polyacrylate-clay sol-gel materials

Organo-functional silanes which were able to form chemical bonds with kaolinite and could also have an affinity to the materials of concern here, were studied by the sol-gel process. Polymethacrylate with trialkoxy silyl functional groups were prepared, hydrolysed and co-condensed with kaolinite. The progress of the hydrolysis, which proceeded very slowly, was followed by Karl-Fischer titration. Thermal behavior was investigated by differential thermal analysis. The extent of the reaction leading to network formation was qualitatively followed by Fourier transform-infrared spectroscopy and X-ray diffraction. Free-radical polymerization was carried out ultrasonically in the presence of a catalyst. Trimethoxy silane end-capped silane was found to be covalently bonded to kaolinite. The copolymers, with various amounts of kaolinite, were then hydrolysed and co-condensed in the presence of a catalyst to yield sol-gel materials which have a controllable combination of properties of both the polymer and kaolinite.     

Corrosion behavior of tempered dual-phase steel embedded in concrete

Dual-phase(DP) steels with different martensite contents were obtained by appropriate heat treatment of an SAE1010 structural carbon steel,which was cheap and widely used in the construction industry. The corrosion behavior of DP steels in con-crete was investigated under various tempering conditions. Intercritical annealing heat treatment was applied to the reinforcing steel to obtain DP steels with different contents of martensite. These DP steels were tempered at 200,300,and 400°C for 45 min and then coo...     

Dispersion-strengthening effect of Cu-based Mn, Al, and Zn rich alloys

In this systematic study, dispersion-strengthening effect of the Cu–25.91Mn (wt.%), Cu–26.62Mn–8.99Al (wt.%), Cu–22.17Mn–12.32Zn (wt.%) ingot alloys have been investigated. Samples were homogenized at a high fixed temperature in different periods and cooled with different cooling rates. After processes, microanalysis of the samples were interpreted by using scanning electron microscope (SEM) and weight percentages of the elements of the occurrence phases in the samples obtained by using electron dispersion spectroscopy (EDS) technique. Additionally, some characteristic properties of the heat treated samples with different conditions of Cu–Mn, Cu–Mn–Al, Cu–Mn–Zn ingot alloys were also discussed.     

Fair referee assignments for professional football leagues

Assignment of referees to football games is an important problem faced in professional football leagues. Despite its importance, the problem has received limited academic attention. This paper presents a model and analysis of the problem for fair referee assignments, and develops a constructive heuristic and a local search procedure for its solution. Results from an extensive computational study show that the methods are effective in solving the problem in a second of computation time and yielding an excellent solution quality.     

Maximization of buckling load of laminated composite plates with central circular holes using MFD method

This paper addresses optimal design of simply supported symmetrically laminated composite plates with central circular holes. The design objective is the maximization of the buckling load, and the design variable is considered as the fiber orientation. The first-order shear deformation theory is used for the finite element analysis. The study is complicated because the effects of bending–twisting coupling are also included for the buckling optimization. The modified feasible direction method is used to solve the optimization problems. Finally, the effect of different number of layers, boundary conditions, width-to-thickness ratio, plate aspect ratios, hole daimeter-to-width ratio, and load ratios on the results is investigated.     

A study of ergonomics factors in washbasin design

A 4-week UNESCO-sponsored mission to the Department of Architecture, Karadeniz Technical University in Eastern Turkey, gave an opportunity to apply ergonomics techniques to some aspects of that country's domestic washbasin design. The study was intended to provide experience in questionnaire design and administration, in the application of psycho-physical methods, and to highlight the importance of determining user characteristics and preferences with regard to the built environment. A field study elicited information on dimensions and positioning of existing wash-basins and ancillary equipment and the opinions of users as to the suitability of these features in relation to the activities performed. A laboratory study, using an adjustable rig permitting variation in the heights of basin, taps and mirror/shelf, followed. The data obtained on preferred heights of these items led to the conclusions that basin height should be increased to between 95 and 100 cm to satisfy the majority of users; tap height above the basin should be reduced to about 11 cm; the shelf and lower edge of a mirror sited above the basin should be 136 cm above the floor; and a clear space of 110 cm should be available between the front of the basin and a wall or other obstruction. Suggestions on other design aspects of the bathroom, resulting from the study, are discussed.     

Standardization problem of author affiliations in citation indexes

Academic effectiveness of universities is measured with the number of publications and citations. However, accessing all the publications of a university reveals a challenge related to the mistakes and standardization problems in citation indexes. The main aim of this study is to seek a solution for the unstandardized addresses and publication loss of universities with regard to this problem. To achieve this, all Turkey-addressed publications published between 1928 and 2009 were analyzed and evaluated deeply. The results show that the main mistakes are based on character or spelling, indexing and translation errors. Mentioned errors effect international visibility of universities negatively, make bibliometric studies based on affiliations unreliable and reveal incorrect university rankings. To inhibit these negative effects, an algorithm was created with finite state technique by using Nooj Transducer. Frequently used 47 different affiliation variations for Hacettepe University apart from “Hacettepe Univ” and “Univ Hacettepe” were determined by the help of finite state grammar graphs. In conclusion, this study presents some reasons of the inconsistencies for university rankings. It is suggested that, mistakes and standardization issues should be considered by librarians, authors, editors, policy makers and managers to be able to solve these problems.     

Preparation and properties of selective polyurethane films and their use for the development of biomedical dopamine sensor

Polyurethane films were synthesized by 3,4-divanillyltetrahydrofuran and different diisocyanates. These prepared polyurethanes were characterized by FT-IR, DSC, DTA, and TGA techniques. For the amperometric applications, synthesized polyurethanes exhibited suitable T_g (°C), good thermal stability and good adhesive properties. In addition, because of their interesting film properties, attempts were made to prepare dopamine-sensing electrode. For this reason, selectivity of film-coated electrodes obtained from the chemically prepared polyurethanes toward electroactive and nonelectroactive species were examined by means of DPV technique. From the electrochemical results obtained, it has been demonstrated that the PU-1-coated electrode can be used for the development of biomedical sensor.