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Global warming associated with the greenhouse effect urge finding alternative energy strategies concerned with sustainable energy resources that are environmentally friendly and provide energy saving. Waste heat recovery engines are attracting devices that convert usually wasted energy to valuable mechanical or electrical energy. The current research aims to develop a mathematical model to investigate the effects of regenerator physical dimensions on the alpha Stirling engine performance indicators. A mathematical model integrating an internal pressure drop has been proposed to act as a thermodynamic optimization tool for the Stirling engine. The main conclusion was that both geometrical factors and working fluid initial charge (gas mass) craft the performance parameters of alpha type Stirling engine that operates with air as working material. After that, Artificial neural networks of Levenberg Marquardt and Orthogonal Distance Regression models, and Fuzzy systems trained for Mass Charge from M = 0.002 to 0.004 Kg are compared to find the least uncertainty. Results revealed that the Fuzzy system and Orthogonal Distance Regression model could predict more effectively than the Levenberg Marquardt model.

A novel and uncomplicated method for preparing nanocrystalline zinc oxide by precipitation in a basic aqueous solution with the addition of an oxidation agent and in the presence of flowing gas is presented. Firstly, the value of pH of the starting solution containing the zinc salts is adjusted to a value of 5–5.5. Then, zinc oxide is precipitated by adding NH₄OH and bubbling flowing air. Finally, the precipitated materials are washed with a basic solution (0.01 M NaOH). The X-ray diffraction patterns show nanocrystalline single-phase ZnO with a grain size of 12–14 nm (Scherrer method). No further thermal treatment of the prepared material is required. The surface of the prepared material can be successfully modified. This new route is reproducible and can be used on industrial level.

The aerobic oxidative cleavage of styrene C=C double bonds catalyzed by simple manganese porphyrin is reported. Under the catalysis of chloro(tetraphenylporphinato)manganese, the oxidative cleavage of the carbon-carbon double bond of the styrene with air yields benzaldehyde. Our results show that the oxidative cleavage and the epoxidation of the styrene double bond are the competition reactions in the styrene-manganese porphyrin-air system. The reaction temperature decided the product distribution. Under the conditions of 0.4 MPa air and 30 ppm of chloro(tetraphenylporphinato)manganese, the styrene conversion was 20.0% and the selectivity of benzaldehyde and styrene oxide was 81.7% and 12.7% respectively when the reaction temperature was 110°C. Styrene conversion was 92.5% and the selectivity of benzaldehyde and styrene oxide was 48.1% and 41.2% respectively when the reaction temperature was 120°C.

Toluene oxidation with molecular oxygen as the sole oxidant, and μ-oxo-bis[tetraphenylporphinatoiron(III)] as the catalyst, are reported. Under the reaction conditions of 438 K and 0.8 MPa, the molar total yields for the products benzaldehyde and benzyl alcohol and the turnover number of the catalyst are 4.35% and 21,830 (based on the metal ion), respectively. Compared with the reaction catalyzed by the corresponding monometalloporphyrin TPPFe^IIICl, the total yields of the oxidation products and the catalyst turnover number by the dimeric iron porphyrin were almost twice those by the former. A possible reaction mechanism of the toluene oxidation by μ-oxo-bis[tetraphenylporphinatoiron(III)] is proposed.

The five metalloporphyrins (T(p-Cl)PPM, M = Fe, Mn, Co, Cu, Zn) with different metal nuclei were synthesized, and their catalytic aerobic liquid-phase oxidations of p-xylene into p-toluic acid, p-toluic aldehyde and terephthalic acid using a low concentration of acetic acid as solvent without any halide additives, were studied. The p-xylene conversions and the oxidation product distributions were found to be affected by the structures and concentration of the metalloporphyrins as well as the reaction parameters such as time, temperature and air pressure. The formation of some intermediate oxidation products in the oxidation process also influenced the reaction conversions and the product distribution. Among the metalloporphyrins used, tetrakis(p-chlorophenylporphinato)manganese chloride (T(p-Cl)PPMnCl) was the most efficient catalyst for the oxidation of p-xylene. Under the conditions of 180 °C and 2.0 MPa, 44% conversion of p-xylene and 85% selectivity of p-toluic acid were obtained. Based on the results obtained, a preliminary mechanism of the oxidation of p-xylene over metalloporphyrins was proposed.

A systematic study on the effect of a catalyst on the aerobic oxidation of cyclohexane was carried out using cobalt isooctanoate, metalloporphyrin p-ClTPPCo and [p-ClTPPFe]₂O as catalysts. The results showed that the metalloporphyrin-catalyzed system performed better than the traditional cobalt salt (Co isooctanoate) in terms of both the reaction conversion and the selectivity of cyclohexanol and cyclohexanone (KA oil). More importantly, we discovered that bisironporphyrin complex, which was traditionally considered to be either non-active or not-so-active for hydrocarbon oxidation, excelled at 155°C, achieving high selectivity for KA oil (80%) and good reaction conversion (13.8%). This result is in sharp contrast to earlier results by others. Meanwhile, the production of adipic acid was also increased and good selectivity of adipic acid among the by-products was also obtained. Our study suggested that [p-ClTPPFe]₂O catalyzed aerobic oxidation could be used to produce adipic acid in addition to KA oil. Some mechanistic rationales were proposed to explain the superior performance of the [p-ClTPPFe]₂O catalyst based on its unique structural and chemical properties.

Manganese tetraphenylporphyrin supported on nano-TiO₂ has been synthesized and structurally characterized. It has been shown to have excellent catalytic activity for the aerobic oxidation of α-pinene. Experimental results showed that this much-enhanced activity could arise from possible co-catalysis between metalloporphyrin and the nano-TiO₂ support. The catalyst can be reused several times with minor loss to its catalytic activity.

The Clean Air Act (CAA) and Clean Water Act (CWA) have been the lynchpins of the U.S. environmental policy for the last half century. Under both acts the federal government sets standards and the states implement, the outcomes of the CAA and CWA have not been the same however. While criteria air pollutants across the nation have been reduced or maintained under the management control strategies of the CAA, far less is known about the effects the CWA has had on water quality, even though, most agree water quality has improved since its implementation. These acts are built on similar frameworks, but the real difference lies on the embedded identification of assessment criteria. The CAA creates a rigid framework for the consistent identification and monitoring of air pollutants, while the CWA relies on a much more flexible system that varies over space and time. Thus, it is the embedded environmental assessment criteria within these acts that have led to different outcomes for similar policies.