Development of a novel hybrid SOFC/GT system and transcritical CO2 cycle for CCHP purpose in the district scale

Journal of Thermal Analysis and Calorimetry - The main target of this work is to optimize a novel hybrid system which includes solid oxide fuel cell, gas turbine, and transcritical CO2 power cycle....     

Magnetic dispersive solid-phase extraction of some polycyclic aromatic hydrocarbons from honey samples using iron (III) oxinate nanocomposite as an efficient sorbent

In this work, iron (III) oxinate magnetic nanocomposite was synthesized and employed as an efficient sorbent for the magnetic dispersive solid-phase extraction of some polycyclic aromatic hydrocarbons from honey samples. In the following, dispersive liquid–liquid microextraction procedure was used for further preconcentration of the analytes. The prepared sorbent was characterized using Fourier transform infrared spectrophotometry, X-ray diffractometry, vibrating sample magnetometry, energy dispersive X-ray spectroscopy, and scanning electron microscopy. The results verified the successful formation of the magnetic sorbent. In the extraction process, the sorbent was added into an aqueous solution and the mixture was vortexed. After completing the adsorption process, the supernatant phase was separated in the presence of a magnet and the analytes adsorbed onto sorbent were eluted by acetonitrile. Then, microliter-level 1,1,1–trichloroethane was mixed with the obtained acetonitrile and injected into NaCl solution. Finally, one microliter of the sedimented phase was injected into gas chromatography-flame ionization detector after centrifugation. Under the optimum conditions, a great repeatability (relative standard deviation equal or less than 5 and 6% for intra– and interday precisions, respectively), acceptable extraction recoveries (59–84%), high enrichment factors (118–168), and low limits of detection and quantification (0.16–0.36 and 0.56–1.22 ng/g, respectively) were acquired.     

Combined heat and mass transfer by hydromagnetic natural convection over a cone embedded in a non-Darcian porous medium with heat generation/absorption effects

 The problem of combined heat and mass transfer by natural convection over a permeable cone embedded in a uniform porous medium in the presence of an external magnetic field and internal heat generation or absorption effects is formulated. The cone surface is maintained at either constant temperature and constant concentration or uniform heat and mass fluxes. In addition, the cone surface is assumed permeable in order to allow for possible fluid wall suction or blowing. The resulting governing equations are non-dimensionalized and transformed into a non-similar form and then solved numerically by an implicit, iterative, finite-difference method. Comparisons with previously published work are performed and excellent agreement between the results is obtained. A parametric study of the physical parameters is conducted and a representative set of numerical results for the temperature and concentration profiles as well as the local Nusselt number and the Sherwood number is illustrated graphically to show special trends of the solutions. Received on 5 June 2000 / Published online: 29 November 2001     

Cu2O nanocrystals with various morphology: Synthesis,characterization and catalytic properties

Cu₂O nanocubes, octahedra, spheres and truncated rhombic dodecahedral were prepared and their structural, morphological, and electronic properties were investigated by X-ray diffraction analysis, X-ray absorption near edge structure, scanning electron microscope and transmission electron microscope and X-ray absorption near edge structure. Cu₂O nanocrystals were successfully employed to catalyze the 1,3-dipolar cycloaddition reaction for the synthesis of 1,4-disubstituted triazoles. Cu₂O nanocubes and octahedral showed the superior catalytic performance in the cycloaddition reaction. These results reveal that crystal-plane engineering of oxide catalysts is a useful strategy for developing efficient catalysts for organic reaction.     

Electrochemical characterization of naproxen and the adsorbed naproxen oxidation products at glassy carbon electrode modified with carboxyl functionalized multi-walled carbon nanotubes and introducing a new route for naproxen determination

Journal of Solid State Electrochemistry - In the present work, a glassy carbon electrode was modified with carboxyl functionalized multi-walled carbon nanotubes (f-MWCNTs) to investigate the...     

Synthesis,spectral characterization,DFT studies and biological activity of novel Ligand 1‐(2‐cyclohexyl thioethyl) piperidine and its complexes with group 12 metal chlorides

C₆H₁₁S^‐Na⁺ (generated insitu by reaction of NaOH with C₆H₁₁SH) on treatment with 1‐(2‐chloroethyl) piperidine hydrochloride under N₂ atmosphere resulted in (1‐(2‐cyclohexyl thioethyl) piperidine) ( L ¹ ) as orange solid. It's complexes having the formula [ZnCl₂. L¹] ( 1 ), [CdCl₂. (L¹)] ( 2 ) and [HgCl₂. L¹] ( 3 ) have been prepared. L ¹ and its complexes 1‐3 were characterized on the basis of physico‐chemical and spectral (FT‐IR, Mass, ¹H, ¹³C and DEPT 135^o NMR) studies. Powder XRD diffraction pattern reveals the crystalline nature of L¹ and complex 1 . Complexes 1‐3 adopt distorted tetrahedral geometry showing bidentate mode of coordination through S and N. Using DFT‐based optimization of structures, the HOMO‐LUMO energy gaps and molecular electrostatic potential maps (EPM) of compound L¹ and complexes 1‐ 3 were theoretically calculated at the B3LYP/6‐311G (d, p) level of theory. HOMO‐LUMO energy gap was calculated which allowed the calculation of relative properties like chemical hardness, chemical inertness, chemical potential, nucleophilicity and electrophillicity index of the synthesized products. The experimentally obtained IR and NMR results showed a good correlation with those of the theoretical ones. Ligand L ¹ and complexes 1‐3 display significant antibacterial and antifungal activity.     

A controllability perspective of dynamic soaring

Dynamic soaring is an exquisite flying technique to acquire energy from the atmospheric wind shear. In this study, a geometric nonlinear controllability analysis of an unmanned aerial vehicle (UAV) under dynamic soaring conditions is performed. To achieve such an objective, the state-of-the-art mathematical tools of nonlinear controllability are summarized and presented to an aeronautical engineering audience. The dynamic soaring optimal control problem is then formulated and solved numerically. The controllability of the UAV along the optimal soaring trajectory is analyzed. More importantly, the geometric nonlinear controllability characteristics of generic flight dynamics are analyzed in the presence and absence of wind shear to provide a controllability explanation for the role of wind shear in the physics of dynamic soaring flight. It is found that the wind shear is instrumental in ensuring controllability as it allows the UAV attitude controls (pitch and roll) to play the role of thrust in controlling the flight path angle. The presented analysis represents a controllability-based mathematical proof for the energetics of flight physics.     

Synthesis and Characterization of Novel Magnetic Poly(urethane-imide)/Fe3O4@SiO2–NH2 Nanocomposites

Russian Journal of Applied Chemistry - Poly(urethane-imide)/Fe3O4@SiO2–NH2 nanocomposites were synthesized by the reaction of 4,4′-diphenylmethane diisocyanate (MDI), polypropylene...     

Synthesis and application of a novel magnetic SBA-15 nanosorbent for heavy metal removal from aqueous solutions

Journal of Sol-Gel Science and Technology - In this work for the first time, magnetic nanoporous SBA-15 functionalized with isatin groups as a magnetic nanosorbent was applied for the simultaneous...