Optimizing a submerged Monascus cultivation for production of red pigment with bug damaged wheat using artificial neural networks

The combined effect of temperature, agitation speed, and light on red pigment production by Monascus purpureus (M. purpureus) Went DSM 1604 using bug damaged wheat was studied using an artificial neural network (ANN). Information retrieved from the ANN was used to determine the optimal operating conditions for pigment production by M. purpureus using bug damaged wheat meal. The developed ANN had R ² values for training, validation, and testing data sets of 0.993, 0.961, and 0.944, respectively. According to the model, the highest pigment production of 1.874 absorbance units at 510 nm (A_{510 nm}) would be achieved at 29°C and 150 rpm under light conditions. The mean value of the experimental results obtained under these optimum conditions was 1.787±0.072 A_{510 nm}, corresponding to a pigment yield of 35.740 A_{510 nm}/g. The study showed that bug damaged wheat can be used as a substrate for red pigment production by M. purpureus.     

Photovoltaic activity of a PolyProDOT derivative in a bulk heterojunction solar cell

We report the photophysical behavior and photovoltaic performance of a poly(3,4-propylenedioxythiophene) (PProDOT) derivative, namely poly-[3,3-dihexyl-3,4-dihydro-2H-thieno(3,4-b)(1,4)dioxepine] (PProDOT(Hx)₂), as an electron donor in bulk heterojunction solar cells blended with the acceptor 1-(3-methoxycarbonyl)propyl-1-phenyl-[6,6]-methanofullerene (PCBM). Devices composed of a 1:4 (w:w) ratio of PProDOT(Hx)₂/PCBM and spin coated from chlorobenzene were characterized by measuring current–voltage characteristics under simulated Air Mass 1.5 (AM1.5) conditions as well as the spectrally resolved photocurrent (IPCE). The influence of different preparation parameters like various blend ratios, spin coating from different solvents, and changing the metal contacts was studied. It was found that the photoluminescence of the polymer is quenched by a factor greater than 100 using blends consisting of PProDOT(Hx)₂ and PCBM (3:2, w:w). Additionally, the photoactive blends were characterized by photoinduced absorption spectroscopy and the results suggest that charge transfer is occurring from PProDOT(Hx)₂ to PCBM. Results from atomic force microscopy reveal that a bicontinuous network, with domain sizes on the order of 100–200 nm, results when a 1:4 blend of PProDOT(Hx)₂/PCBM is spin coated from chlorobenzene.     

Communicating Probability Distributions

A rate distortion problem is solved that is motivated by a quantum data compression problem. The goal is to send information about a source string x so that a receiver can construct a second string y for which the joint empirical probability distribution of x and y is close to some desired distribution. The problem differs from the usual rate distortion problems in that one must consider both remote sources and distortion functions that are not averages of per-letter distortion functions     

Synthesis of chitosan beads as boron sorbents

Parameters, such as pH, temperature, initial boron concentration, adsorbent dosage, and ionic strength, affecting boron adsorption onto chitosan beads were examined in this study. The following values were obtained as the optimum conditions in our studied ranges: pH 8.0, temperature = 308 K, amount of chitosan beads = 0.15 g, initial boron concentration = 4 mg L⁻¹, and ionic strength = 0.1 M NaCl]. The adsorption kinetics were also examined in terms of three kinetic models: the pseudo‐first‐order, pseudo‐second‐order, and intraparticle diffusion models. The pseudo‐second‐order kinetic model showed very good agreement with the experimental data. Intraparticle plots seemed to have two steps and indicated multilinearity. Equilibrium data were evaluated with nonlinear and linear forms of the Langmuir and Freundlich equations. The experimental data conformed to the Freundlich equation on the basis of the formation of multilayer adsorption. To characterize the synthesized chitosan beads, we used Fourier transform infrared (FTIR) spectroscopy and scanning electron microscopy (SEM) analyses. As shown by FTIR analysis, the boron species may have interacted with the NH₂ groups on chitosan. Microparticles of about 5 μm appeared in the SEM micrographs of the chitosan beads. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Preparation and characterization of polypyrrole/selenium composites

This article reports synthesis of polypyrrole (PPy) and its composites having various amounts of selenium (Se) in the presence of nitric acid in aqueous medium via chemical oxidative polymerization. Samples were spectroscopically characterized using Fourier transform infrared spectroscopy, ultraviolet‐visible spectroscopy, and atomic absorption spectroscopy. Although morphology of the samples was examined by using scanning electron microscopy (SEM), their thermal properties were studied via differential scanning calorimetry (DSC). The alternating current (ac) conductivity and dielectric properties were investigated as a function of temperature. Variation of adsorption free energy obtained from Langmuir adsorption isotherm showed that metal cations were physically adsorbed onto the polymer surface. SEM images showed that filling process significantly changes the morphology of PPy. DSC results indicated that cold crystallization temperature (T_cc) of unfilled PPy decreases with increasing filling level. Dielectric measurements showed that relaxation times for PPy and its composites have decreased linearly with increasing temperature. The conductivity of the PPy, when filled with 1 g of Se, increased ～ four times at room temperature for 1 kHz. POLYM. ENG. SCI., 2013. © 2012 Society of Plastics Engineers     

Challenges for the security analysis of Next Generation Networks

The increasing complexity of information and telecommunications systems and networks is reaching a level beyond human ability, mainly from the security assessment viewpoint. Methodologies currently proposed for managing and assuring security requirements fall short of industrial and societal expectations. The statistics about vulnerabilities and attacks show that the security, reliability and availability objectives are not reached and that the general threat situation is getting worse. With the deployment of Next Generation Networks – NGNs, the complexity of networks, considering their architecture, speed and amount of connections, will increase exponentially. There are several proposals for the network and security architectures of NGNs, but current vulnerability, threat and risk analysis methods do not appear adequate to evaluate them. Appropriate analysis methods should have some additional new characteristics, mainly regarding their adaptation to the continuous evolution of the NGNs. In addition, the application of security countermeasures will require technological improvements, which will demand further security analyses. This paper evaluates the current vulnerability, threat and risk analysis methods from the point of view of the new security requirements of NGNs. Then, the paper proposes to use autonomic and self-adaptive systems/applications for assuring the security of NGNs.     

The estimation of NMVOC emissions from an urban-scale wastewater treatment plant

The emissions of 19 different non-methane volatile organic compounds (NMVOCs) from the sewage treatment plant of the province of Eski?ehir in Turkey were estimated. The estimations were based on the modified surface-renewal model suggested by EPA. The estimated total annual amounts of the pollutants emitted (from the plant's primary and secondary clarifier units and their weirs, as well as the aerated biological treatment unit) varied between a range of 0.00024 t (1,3-dichlorobenzene) and 0.1646 t (tetrachloroethylene). The corresponding flux data ranged from 9.98 x 10(-10)g cm(-2) h(-1) (1,3-dichlorobenzene) to 8450 x 10(-10)g cm(-2) h(-1) (tetrachloroethylene). Resulting total hourly NMVOC emission rate (0.041 kg h(-1)) was found not to exceed the current national standards. This work may be considered as a regional background for a possible contribution to the national and international emission inventory study on NMVOCs.