Evaluation of Input Variables in Adaptive-Network-Based Fuzzy Inference System Modeling for an Anaerobic Wastewater Treatment Plant under Unsteady State

A conceptual neural-fuzzy model based on adaptive-network-based fuzzy inference system (ANFIS) was proposed to estimate effluent chemical oxygen demand (COD) of a full-scale anaerobic wastewater treatment plant for a sugar factory operating at unsteady state. The fitness of simulated results was improved by adding two new input variables into the model; phase vectors of operational period and effluent COD values of last five days (history). In modeling studies, individual contribution of each input variable to the resulting model was evaluated. The addition of phase vectors and history of five days into the input variable matrix in ANFIS modeling for anaerobic wastewater treatment was applied for the first time in literature to increase the prediction power of the model. By this way, the correlation coefficient between estimated and measured values of output variable (COD) could be increased to the value of 0.8940, which is considered a good fit.     

Photocatalytic degradation of Remazol Red F3B using ZnO catalyst

The photocatalytic degradation of aqueous solution of a commercial azo-reactive textile dye, Remazol Red F3B, has been investigated in a batch slurry reactor, in the presence of ZnO catalyst using two different UV light sources emitting at 254 nm and 365 nm. The effects of various process variables on degradation performance of the process have been investigated. The results showed that decolourization and total organic carbon (TOC) removal are both affected in the same manner by the solution pH in the pH range 6-10, showing maxima at pH 7 and pH 10. They are inversely related to the dye concentration, they increase in power-law with the light intensity. Decolourization is faster with 365 nm UV. TOC removal is not affected by UV wavelength in the initial period up to 20 min, after which it progresses faster under 365 nm UV radiation. These results indicate that the UV wavelength influences especially the degradation rate of the intermediate products generated during the initial period of the photocatalytic process. Finally, catalyst loading affects both efficiencies in the same trend, which are maximized at about 2 g/l catalyst loading.     

Seasonal fat and fatty acids variations of seven marine fish species from the Mediterranean Sea

Seasonal variations of proximate compositions, muscle lipids and fatty acids (FA) of seven seawater species (Silllago sihoma, Upeneus pori, Sparus aurata, Saurida undosquamis, Epinephelus auneus, Mullus barbatus, Solea solea) from the Mediterranean Sea, were determined in all seasons. The results showed that the fatty acid compositions of each species ranged from 26.41 to 38.70% saturated (SFA), 13.78 to 26.52% monounsaturated (MUFAs) and 25.02 to 50.83% PUFAs. The highest proportions of EPA were obtained from M. barbatus (8.34%) in spring, S. sihoma (7.54%), U. pori (6.75%), S. aurata (6.31%), S. undosquamis (5.12%), E. auneus (5.10%) in summer, and also S. solea (6.19%) in spring. The highest proportions of DHA were found in spring, ranging from 25.14% for M. barbatus to 34.87% for S. aurata, except for S. solea (30.44%) in winter and S. sihoma (15.83%) in summer. The results showed that from a quality point of view, all species were suitable for human nutrition, since muscle lipids are rich in EPA + DHA in all seasons. Practical application : The American and Canadian Dietetic Associations recommend two servings of fatty fish per week and a daily combined intake of EPA and DHA of 500 mg. This follows a trend of numerous publications and other guidelines recognizing the health benefits of long‐chain n‐3 PUFA from fish or marine microbial sources with respect to cardiovascular health, neurological diseases, infant health and development, inflammation and cancer and other health effects. The seven species analyzed here provide muscle lipids that are rich in EPA and DHA. Only minor season‐to‐season changes in the total content of n‐3 and n‐6 PUFA were observed for the same species. The results provide valuable information for preparing diet tables.     

A two-stage bid-price control for make-to-order revenue management

Capacity control implementations in make-to-order (MTO) revenue management typically are based on bid-prices, which are used to approximate the opportunity cost of accepting a customer request. However, in the face of stochastic demand, this approximation becomes less accurate and the performance of bid-prices may deteriorate. To address this problem, we examine the informational dynamics inherent in MTO capacity control problems and propose a two-stage capacity control approach based on bid-price updates. Updating is realized with neural networks, which are applied to adjust the selection criteria during the booking period with respect to online demand information. Not only is the resulting contribution margin positively influenced by the update, but also the downside risk of performing worse than a naive first-come-first-served policy. Results from computational experiments show that the proposed approach dominates traditional revenue management methods like randomized linear programming with and without resolving in expected contribution margin as well as in risk.     

Alkali catalyzed transesterification of safflower seed oil assisted by microwave irradiation

The safflower (Carthamus tinctorius L.) oil was extracted from the seeds of the safflower that grows in Diyarbakir, SE Anatolia of Turkey. Biodiesel has been prepared from safflower seed by transesterification of the crude oil under microwave irradiation, with methanol to oil molar ratio of 10:1, in the presence of 1.0% NaOH as catalyst. The conversion of C. tinctorius oil to methyl ester was over 98.4% at 6 min. The important fuel properties of safflower oil and its methyl ester (biodiesel) such as density, kinematic viscosity, flash point, iodine number, neutralization number, pour point, cloud point, cetane number are found out and compared to those of no. 2 petroleum diesel, ASTM and EN biodiesel standards. Compared with conventional heating methods, the process using microwaves irradiation proved to be a faster method for alcoholysis of triglycerides with methanol, leading to high yields of biodiesel.     

Simultaneous evaluation of effective diffusion coefficients of the substrates in a biofilm with a novel experimental method

In this study, a pure culture of Zoogloea ramigera was grown as a film on active carbon particles in a differential fluidized bed biofilm reactor (DFBBR) as a novel experimental system for the application of diffusion-reaction models. The effective diffusion coefficients of the essential substrates; glucose, ammonium ion and oxygen in the active biofilm were simultaneously calculated. The values of effective diffusion coefficients in the active biofilm to those in water varied between 13–34, 48–96 and 28–48% for glucose, ammonium ion and oxygen, respectively, at different biofilm densities, which is in fair agreement with the literature.     

Amino acid and fatty acid composition of wild sea bass (Dicentrarchus labrax): a seasonal differentiation

Seasonal variations in the amino acid and fatty acid compositions of wild sea bass (Dicentrarchus labrax) captured in the north eastern Mediterranean were investigated. In all seasons, the major amino acids in sea bass fillets were determined to be aspartic acid, glutamic acid and lysine. Methionine, tyrosine and histidine composition of the fillets were lower than those of the other amino acids in all seasons. The ratios of essential (E, g amino acid/16 g N)/nonessential (NE, g amino acid/16 g N) amino acids were observed to be 0.75 for winter, 0.76 for autumn, 0.77 for both spring and summer. Results showed that, sea bass fillets are well-balanced food source in terms of E/NE ratios in all seasons. In addition, seasonal differences in polyunsaturated fatty acid (PUFA) composition of the fillets were observed in all seasons. The major fatty acids of sea bass fillets were observed to be palmitic acid (16:0), oleic acid (18:1ω9), eicosapentaenoic acid (EPA, 20:5ω3) and docosahexaenoic acid (DHA, 22:6ω3). The amounts of EPA+DHA in autumn, winter, spring and summer were determined as 0.16, 0.12, 1.14 and 1.02 g/100 g wet weight, respectively.     

The degradation of an azo dye in a batch slurry photocatalytic reactor

The photocatalytic degradation of a commercial azo-reactive textile dye, Remazol Red F-3B, has been investigated in a batch slurry reactor using semiconductor catalysts like, ZnO and TiO₂, and two UV sources emitting mainly at 254 and 365 nm. Non-irradiated catalysts and non-catalyzed UV irradiation have negligible effect on the dye degradation. Initial pH, dye concentration, light power and catalyst loading as well as the catalyst type and UV wavelength are considered as process variables. The results showed that decolorization and TOC removal efficiencies of ZnO are higher under 365 nm UV. On the other hand, when two photocatalysts are compared, the decolorization performance of ZnO is higher than TiO₂ under 365 nm UV_, while TiO₂ performs better under 254 nm UV. Furthermore, from the TOC removal point, TiO₂ performs better than ZnO irrespective of the UV wavelength. TiO₂ irradiated under 254 nm UV degrades successfully both benzene and naphthalene derivatives.