Hydrogen and Methane Production, Energy Recovery, and Organic Matter Removal from Effluents in a Two-Stage Fermentative Process

This study evaluates the potential for using different effluents for simultaneous H₂ and CH₄ production in a two-stage batch fermentation process with mixed microflora. An appreciable amount of H₂ was produced from parboiled rice wastewater (23.9?mL g^?1 chemical oxygen demand [COD]) and vinasse (20.8?mL g^?1 COD), while other effluents supported CH₄ generation. The amount of CH₄ produced was minimum for sewage (46.3?mL g^?1 COD), followed by parboiled rice wastewater (115.5?mL g^?1 COD) and glycerol (180.1?mL g^?1 COD). The maximum amount of CH₄ was observed for vinasse (255.4?mL g^?1 COD). The total energy recovery from vinasse (10.4?kJ g^?1 COD) corresponded to the maximum COD reduction (74.7?%), followed by glycerol (70.38?%, 7.20?kJ g^?1 COD), parboiled rice wastewater (63.91?%, 4.92?kJ g^?1 COD), and sewage (51.11?%, 1.85?kJ g^?1 COD). The relatively high performance of vinasse in such comparisons could be attributed to the elevated concentrations of macronutrients contained in raw vinasse. The observations are based on kinetic parameters of H₂ and CH₄ production and global energy recovery of the process. These observations collectively suggest that organic-rich effluents can be deployed for energy recovery with sequential generation of H₂ and CH₄.     

Sonochemically prepared organozinc reagents1. conjugate additions to α-β unsaturated aldehydes

Organozinc reagents, prepared by sonication from organic halides, lithium and zinc bromide, add conjugatively to α-enals in the presence of nickel acetylacetonate. Satisfactory yields are obtained from arylbromides.     

Does the Big Rip survive quantization?

It is known that certain quantum cosmological models present quantum behavior for large scale factors. Since quantization can suppress past singularities, it is natural to inquire whether quantum effects can prevent future singularities. To this end, a Friedmann–Robertson–Walker quantum cosmological model dominated by a phantom energy fluid is investigated. The classical model displays accelerated expansion ending in a Big Rip. The quantization is performed in three different ways, which turn out to lead to the same result, namely there is a possibility that quantum gravitational effects could not remove the Big Rip.     

Self-focusing in new kerr media: Large thermal nonlinearity in metallotetraphenylporphins

A large optical nonlinearity of thermal origin has been observed in acetone solutions of a series of tetraphenylporphin, TPPH₂, MnTPP(CH₃CO₂ ^–), FeTTPCI^-, CoTPP, NiTPP, and CuTPP. The nonlinear Kerr coefficient is sensitively dependent on the nature of central metals in the compounds. The Mn compound exhibits the largest coefficient, 6 × 10^–5 esu, for 514 nm laser wavelength. The use of prophins offers increased flexibility in the preparation of different Kerr media.Presented at the International Workshop on Squeezed and Correlated States in Quantum Optics, Moscow, December 3–7, 1990.     

Adsorption of components of enzymatic synthesis of ampicillin on different hydrophobic resins

This work compared the performance of three hydrophobic resins for the adsorption of ampicillin (AMP), d-phenylglycine (PG), d-phenylglycine methyl ester (PGME), and 6-aminopenicillanic acid (6-APA). The influence of pH on adsorption efficiencies was assessed in the range of 4.5–8.5, at 4 and 25°C. The values at 4°C were slightly higher than those at 25°C. The adsorption efficiency of AMP and 6-APA decreased at higher pHs, for the three resins. An opposite behavior was found for PGME, and the pH did not affect PG adsorption efficiency. Isotherm models were fitted to experimental equilibrium data and the best models were discriminated.     

Comparative analysis of dengue versus chikungunya outbreaks in Costa Rica

For decades, dengue virus has been a cause of major public health concern in Costa Rica, due to its landscape and climatic conditions that favor the circumstances in which the vector, Aedes aegypti, thrives. The emergence and introduction throughout tropical and subtropical countries of the chikungunya virus, as of 2014, challenged Costa Rican health authorities to provide a correct diagnosis since it is also transmitted by the same vector and infected hosts may share similar symptoms. We study the 2015–2016 dengue and chikungunya outbreaks in Costa Rica while establishing how point estimates of epidemic parameters for both diseases compare to one another. Longitudinal weekly incidence reports of these outbreaks signal likely misdiagnosis of infected individuals: underreporting of chikungunya cases, while overreporting cases of dengue. Our comparative analysis is formulated with a single-outbreak deterministic model that features an undiagnosed class. Additionally, we also used a genetic algorithm in the context of weighted least squares to calculate point estimates of key model parameters and initial conditions, while formally quantifying misdiagnosis.     

Green synthesis and antibacterial activity of chalcogenoesters

Herein, we present a new variation for an eco-friendly methodology for the synthesis of chalcogenoester in good-to-excellent yields in a short time, with an easy work-up/purification step, and in a greenest methodology, affording the minimum generation of solid and liquid waste, in comparison to that described in the literature. Additionally, some selected compounds were evaluated as antimicrobial agents, showing moderate activity against a variety of microorganisms including the K. pneumoniae, P. aeruginosa and also some selected fish pathogenic bacteria.     

Continuous clavulanic acid adsorption process

Adsorption kinetics and equilibrium data of clavulanic acid, a β-lactam antibiotic, on ion-exchange resin Amberlite IRA 400 were utilized to carry out the modeling and simulation of a continuous adsorption process. These simulations allowed the estimation of yield, concentration, and purification factors of the process utilizing the product final concentration. Experimental runs of this process were carried out using the conditions pointed out by simulation studies. Comparison of the experimental results and those calculated by the proposed model showed that the model could describe very well the main features of the continuous process.     

Determination of alcohol content in beverages using short-wave near-infrared spectroscopy and temperature correction by transfer calibration procedures

This paper reports the utilization of short-wave near-infrared (SW-NIR) transmission spectroscopy for rapid and conclusive analysis of alcoholic content (% v/v) in beverages. This spectral region is interesting because common visible diode array spectrometers can be utilized, reducing time and costs in comparison with traditional near-infrared or mid-infrared instruments. A correction of external temperature influence is necessary, and for this purposes two calibration transfer procedures were compared: piecewise direct standardization (PDS) and orthogonal signal correction (OSC). The RMSEP found for the alcoholic content model at 20 °C was 0.13% v/v and, after application of transfer calibration procedures at other temperatures (15, 25, 30 and 35 °C) using the model built at 20 °C, errors of the same order of magnitude were obtained.