The novel pyridine based symmetrical Schiff base ligand and its transition metal complexes: synthesis,spectral definitions and application in dye sensitized solar cells (DSSCs)

The pyridine based azo-linked symmetrical Schiff base ligand, (E)-2,2′-((1E,1′E)-(pyridine-2,6-diylbis(azanylylidene))bis(methanylylidene))bis(4-((E)-phenyldiazenyl)phenol) (H₂L), and its Co(II), Ni(II) and Pd(II) transition metal complexes were prepared, and defined by using elemental analysis, Fourier transform infrared, UV–visible, mass, nuclear magnetic resonance spectra, molar conductance, magnetic susceptibility and thermal analysis techniques. The conductivity results pointed out the non-electrolytic nature of all metal complexes. Elemental composition, ultraviolet spectra and magnetic susceptibility data showed that the synthesized complexes are in the binuclear structure and square plane geometry. When compared to the characteristic infrared bands for the functional groups of the ligand structure with complex molecules are reached, the ligand binds to the metal atom via phenolic OH and azomethine-nitrogen. Furthermore, the dye-sensitized solar cells (DSSCs) based on H₂L and its metal complexes were fabricated, and photovoltaic properties of these devices were also investigated. The power conversion efficiency of fabricated devices based on ligand H₂L can be improved with the incorporation of the transition metal complex.     

Assessment of the Turkish utility sector through energy and exergy analyses

The present study deals with evaluating the utility sector in terms of energetic and exergetic aspects. In this regard, energy and exergy utilization efficiencies in the Turkish utility sector over a wide range of period from 1990 to 2004 are assessed in this study. Energy and exergy analyses are performed for eight power plant modes, while they are based on the actual data over the period studied. Sectoral energy and exergy analyses are conducted to study the variations of energy and exergy efficiencies for each power plants throughout the years, and overall energy and exergy efficiencies are compared for these power plants. The energy utilization efficiencies for the overall Turkish utility sector range from 32.64% to 45.69%, while the exergy utilization efficiencies vary from 32.20% to 46.81% in the analyzed years. Exergetic improvement potential for this sector are also determined to be 332 PJ in 2004. It may be concluded that the methodology used in this study is practical and useful for analyzing sectoral and subsectoral energy and exergy utilization to determine how efficient energy and exergy are used in the sector studied. It is also expected that the results of this study will be helpful in developing highly applicable and productive planning for energy policies.     

溶胶-凝胶法制备钛基生物相容性MgO膜

植入物的表面修饰对于获得生物相容性或功能性界面非常重要。本项研究中, 钛金属表面的MgO薄膜在400?C进行溶胶-凝胶化,观察其微观结构、生物活性、抗菌性能和细胞毒性。结果发现,MgO在空气中老化后转化为Mg（OH）2。扫描电镜观察薄膜无裂纹。在模拟体液试验中显示出良好的生物活性,与成骨细胞有良好的相容性,对大肠杆菌有轻微的抗菌作用。MgO薄膜在钛金属生物医学植入物表面改性中具有潜在的应用前景。     

One-Dimensional Coordination Polymer of Zinc(II)-pyridine-2,5-dicarboxylate with N,N-Dimethylethylenediamine: Synthesis, Structural, Spectroscopic and Thermal Properties

In this study, a new polymeric Zn(II)-pyridine-2,5-dicarboxylate complex with N,N-dimethylethylenediamine (dmen), {[Zn(pydc)(dmen)(H₂O)]·H₂O} _n (1) (pydc = pyridine-2,5-dicarboxylic acid or isocinchomeronic acid), has been synthesized. Elemental, thermal analysis and IR spectroscopic study have been performed to characterize the complex. The molecular structure of complex has been determined by the single crystal X-ray diffraction. 1 has been observed to crystallize in the orthorhombic space group Pbca. The Zn(II) atom is coordinated by the tridentate pydc bridging ligand through the oxygen atom of the carboxylate group and the nitrogen atom of the pyridine ring in a bidentate manner and the oxygen atom of carboxylate group of other pydc ligand. Each Zn(II) ion is also coordinated by a bidentate dmen and one aqua ligand forming a distorted octahedral geometry. The crystal packing of complex is a composite of intermolecular hydrogen bonding with C=O?π and C–H?π interactions.     

Novel Copper(II) Complexes of <Emphasis Type="Italic">N</Emphasis>-Phenylanthranilic Acid Containing Ethanol and Hydroxo Ligands

The complexes, tetra-μ-[2-(phenylamino)benzoato](O,O′)-bis[(ethanol)copper(II)] (1) and di-μ-[2-(phenylamino)benzoato](O,O′)-bis[(hydroxo)copper(II)] (2), were synthesized by the reaction of N-phenylanthranilic acid and CuCl₂·2H₂O in an ethanol water mixture. In complex 1, each Cu(II) atom, which is in a slightly distorted square pyramidal environment, is coordinated equatorially by four N-phenylanthranilate O-atoms and axially by the ethanol O-atoms. In complex 2, [Cu₂(C₆H₅NHC₆H₄COO)₂(OH)₂], each Cu(II) atom, which is in tetrahedral environment, is coordinated by two N-phenylanthranilate O-atoms and hydroxo ligands. The crystal structure (monoclinic, P21/c space group) of complex 1 comprises a dinuclear [Cu₂(C₆H₅NHC₆H₄COO)₄(CH₃CH₂OH)₂] species and the dimer is located on a crystallographic inversion centre. The Cu(II) ions, 2.591(2) Å apart, are bridged by the carboxylate groups of four N-phenylanthranilate ligands. The complex molecules show three-dimensional supramolecular networks by O–H···O, C–H···O and C–H···π interactions.     

Volume ratio and pressure drop on hydraulic dynamic pressure calibration system

The calibration of a pressure transducer that works in dynamic conditions is an unavoidable challenge. To address this challenge, an experimental setup has been designed and developed to simultaneously generate and calibrate the dynamic pressure. The system mainly comprises a pressure chamber that accommodates a step pressure generator and test chamber with a quick open valve and pressure sensor under calibration. Accordingly, an aperiodic type of step pressure generator with a quick open valve is particularly designed. This instrument can generate a positive step pressure with a rise time of up to 11 ms and a negative step pressure with a fall time of up to 12 ms within a working pressure range from the atmospheric pressure to 200 MPa. The volume ratio of the test chamber to the pressure chamber and its effect on pressure drop is critical in such systems. The effect of volume ratio on the dynamic performance parameters, namely, rise/fall time, is explored and inferences for optimizing these parameters are derived. A mathematical model for pressure drop in the test chamber has been developed and validated to precisely determine the magnitude of the step pressure input. Lastly, the experimental study of the effect of volume ratio on pressure drop has been conducted to diminish the pressure drop, thereby minimizing the uncertainty.     

Thermoeconomic analysis of energy utilization in the residential–commercial sector: An application

Thermoeconomic analysis is a very useful tool for investigators in engineering and other disciplines since its methodology includes the quantities such as mass, energy, exergy and cost. This study deals with this analysis of energy utilization in the residential–commercial sector (RCS). In this regard, the relations between capital costs and thermodynamic losses for subsectors in the RCS are investigated. In the analysis, Turkey is taken as an application country based on its actual and projected values for the years 1991, 1993, 1995, 1999, 2000 and 2001, and for the year 2020, respectively. It is observed from the results obtained that the maximum exergy destructions in the system particularly occur due to the utilization of the large-cost and high-quality energy sources like petroleum, natural gas carriers in the low-energy needs. In conjunction with this, the values for the total exergy losses are found to vary from 486.43 to 2797.28 PJ, while those for the improvement potential are obtained to range from 58.80 to 1870 PJ in the Turkish RCS for the analyzed years. The ratio of thermodynamic loss rate-to-capital cost values is also calculated to be in the range of 0.76–1.01. It is expected that the results presented here would be beneficial to the researchers, government administration and engineers working in the area of modeling the subsectors of countries using thermoeconomic analysis method.