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In this study, an exergy optimization has been performed for a cogeneration plant consisting of an irreversible Carnot heat engine. In the analysis, different objective functions have been defined based on alternative performance criteria and the optimum values of the design parameters of a cogeneration cycle were determined for different criteria. In this context, the effects of irreversibilities on the exergetic performance are investigated, and the results are discussed. List of SymbolṡE Exergy ratė Q Rate of heat transfer I Irreversibility parameter R Power to process heat ratio S Entropy T Temperaturė W Power generated from the cogeneration system M. Atmaca (B) · M. Gumus · A. T. Inan

Production of the bioceramics on the market is presently conducted from typical precipitation method by using reagent grade raw chemicals or through calcination of natural sources like animal bones (especially bovine bone) and fish bones. Usually fish bones were damped near or in the water sources, which can lead to serious environmental pollution. Those were regarded as a trash, even though they still bear economic value, including conjugates. In this study bones of Atlantic Salmon (Salmo salar) were used as a bioceramic material source. Bones of Atlantic Salmon were collected from Besiktas Fish Market. Those were cleaned from possible flesh with reagent grade NaOH. Cleaned parts were washed with demineralized water very neatly. Dry fish bones were calcinated at 850• C for 4 hours. The obtained hydroxyapatite material was characterized with scanning electron microscopy and X-ray diffraction methods. It was found that the bioceramic material consisted of hydroxyapatite and various related phases. Scanning electron microscopy studies have revealed nano-structured bioceramic particles. The aim of this study is to obtain nano-structured bioceramics from bones of Atlantic Salmon in an environmentally friendly and economic way.

In the first part of this study hydroxyapatite was prepared synthetically through classical wet precipitation, using Ca(NO3)2·4H2O (calcium nitrate tetrahydrate) as calcium source and HgN2O4P as phosphate source. In the second part of the study HA compounds were prepared with different ratios (0.5, 1, 2, 5, 10 and 25 wt.%) of antibacterial materials like copper (Cu), silver (Ag) and europium (Eu), using the same wet precipitation method. The prepared pure HA material was utilized as the control group for comparison with Cu/Ag/Eu/HA composites. Studies of X-ray diffraction, FTIR spectroscopy, scanning electron microscopy, equipped with energy dispersive X-ray analysis were performed. The aim of this study was to investigate Cu/Ag/Eu/HA composites and the effect of metals on HA biomaterials, used as scaffold materials in bone disease treatment.

This study is the investigation of grooved circular jet ow experimentally and using computational uid dynamics (CFD). Experimental studies were conducted by using straight circular and grooved circular tubes in a multi-purpose low-range subsonic wind tunnel. Single channel hot wire anemometer was used in turbulence measurements. Numerical studies for the solution of jet ow were performed through FLUENT program (ANSYS 14.5).Jet ow proles at dierent velocities were formed by using the data generated at predetermined stations in the Re b ). These parameters were calculated with reference to jet radius and jet half width. Graphics formed by the generated non-dimensional data were compared to the previous studies.

Material research and development studies are focused on different techniques of bringing out nanomaterials with desired characteristics and properties. From the point of view of materials development, nowadays scientists are strongly focused on obtaining materials with predefined characteristics and properties. The morphology control seems to be a determinant factor and increasing attention is devoted to this aspect. At this moment it is possible to engineer the material's features by using different methods and materials combination for both medical and industrial applications. In the applications of chemistry and synthesis, biology, mechanics, optics solar cells and microelectronics tailoring the adjustable parameters of stoichiometry, chemical structure, shape and segregation are evaluated and opens new fields. Because of the magnetic features of nanoparticles and durable particle size, less than 100 nm, this study is aiming to describe their uses in practical applications. That's why the whole hydrodynamic magnetic core shell topic will be reviewed on this paper. Additionally, the properties acting in general sight in solid-state physics are utilized for material selection and for defining issue connecting the core, shell structure and their producing properties. Here, in the study of core/shell nanoparticle various physical and chemical synthesis routes and the effect of electrospun method are briefly discussed. Starting from a real void of the scientific literature, the existent data related to the 1D magnetic electrospun materials are reviewed. The perspectives in the medical, environmental or energetic sector is great and bring some real advantages related to the 0D core@shell structures because both mechanical and biological properties are dependent on the morphology of the materials.