Thermodynamic and heat transfer analysis of heat recovery from engine test cell by Organic Rankine Cycle

During manufacture of engines, evaluation of engine performance is essential. This is accomplished in test cells. During the test, a significant portion of heat energy released by the fuel is wasted. In this study, in order to recover these heat losses, Organic Rankine Cycle (ORC) is recommended. The study has been conducted assuming the diesel oil to be composed of a single hydrocarbon such as C₁₂H₂₆. The composition of exhaust gases (products of combustion) have been computed (and not determined experimentally) from the stoichiometric equation representing the combustion reaction. The test cell heat losses are recovered in three separate heat exchangers (preheater, evaporator and superheater). These heat exchangers are separately designed, and the whole system is analyzed from energy and exergy viewpoints. Finally, a parametric study is performed to investigate the effect of different variables on the system performance characteristics such as the ORC net power, heat exchangers effectiveness, the first law efficiency, exergy destruction and heat transfer surfaces. The results of the study show that by utilizing ORC, heat recovery equivalent to 8.85 % of the engine power is possible. The evaporator has the highest exergy destruction rate, while the pump has the lowest among the system components. Heat transfer surfaces are calculated to be 173.6, 58.7, and 11.87 m² for the preheater, evaporator and superheater, respectively.     

A Simple Reduction Method of Azo-Compounds to Amines Using Fe Powder in the Presence of NH<Subscript>4</Subscript>Cl

Summary. A series of azo-compounds were reduced to related aromatic amines in the presence of Fe powder and ammonium chloride. This one step protocol led to the formation of products in middle to high yields, especially when electron releasing substituted aromatic azo-compounds were reduced.     

Synthesis of 1,2,4‐triazolo[1,5‐d]‐1,2,4‐triazine‐5‐thiones

In an attempt to discover bicyclic compounds containing the 1,2,4‐triazine moiety, 1,2,4‐triazolo[1,5‐d]‐1,2,4‐triazine‐5‐thiones from one pot reaction of arylnitriles with 4‐amino‐1,2,4‐triazine‐3‐thione‐5‐one in the presence of potassium tert‐butoxide were synthesized.     

A spectrophotometric and thermodynamic study of the charge-transfer complexes of iodine with nortriptyline and imipramine drugs in chloroform and dichloromethane solutions

The interaction of iodine as electron acceptor with nortriptyline and imipramine drugs as electron donors has been investigated spectrophotometrically at various temperatures in chloroform and dichloromethane solutions. The observed time dependence of the charge–transfer band and subsequent formation of in solution were related to the slow transformation of the initially formed iodine: drug outer complex to an inner electron donor–acceptor (EDA) complex, followed by fast reaction of the inner complex with iodine to form a triiodide ion. The pseudo-first-order rate constants and activation parameters for the transformation process were evaluated from the absorbance-time data. Stoichiometrices of the complexes were defined by the Job’s method of the continuos variation and obtaind 2: 1 for iodine: drug complexes. The formation constants and molar absorptivities were evaluated from the absorbance-mole ratio data. Thermodynamic parameters of the complexes have been determined from the temperature dependence of the stability constant by Van’t Hoff equation.     

TiCl2(OTf)-SiO2: A solid stable lewis acid catalyst for Michael addition of α-Aminophosphonates,Amines, Indoles and Pyrrole

TiCl₂(OTf)-SiO₂ is simply prepared by immobilization of TiCl₃(OTf) on silica gel surface and introduced as a non-hygroscopic Lewis acid catalyst for C-N and C-C bond formation via Michael addition reaction. A variety of structurally diverse nitrogen nucleophiles including α-aminophosphonates, aliphatic and aromatic amines and imidazole were evaluated as Michael donors. Friedel–Crafts alkylation of indoles and pyrrole was also investigated through Michael addition reaction in the presence of TiCl₂(OTf)-SiO₂ as a catalyst. The reactions were conducted at room temperature or 60 °C under solvent-free conditions and the desired Michael adducts were obtained in high to excellent yields.