Towards automated first-order abduction: the cut-based approach

Traditional abduction imposes as a precondition the restriction that the background information may not derive the goal data. In first-order logic such precondition is, in general, undecidable. To avoid such problem, we present a first-order cut-based abduction method, which has KE-tableaux as its underlying inference system. This inference system allows for the automation of non-analytic proofs in a tableau setting, which permits a generalization of traditional abduction that avoids the undecidable precondition problem. After demonstrating the correctness of the method, we show how this method can be dynamically iterated in a process that leads to the construction of non-analytic first-order proofs and, in some terminating cases, to refutations as well.

Rounding of a first-order quantum phase transition to a strong-coupling critical point

We investigate the effects of quenched disorder on first-order quantum phase transitions on the example of the N-color quantum Ashkin-Teller model. By means of a strong-disorder renormalization group, we demonstrate that quenched disorder rounds the first-order quantum phase transition to a continuous one for both weak and strong coupling between the colors. In the strong-coupling case, we find a distinct type of infinite-randomness critical point characterized by additional internal degrees of freedom. We investigate its critical properties in detail and find stronger thermodynamic singularities than in the random transverse field Ising chain. We also discuss the implications for higher spatial dimensions as well as unusual aspects of our renormalization-group scheme. DOI: 10.1103/PhysRevB.86.214204

Immobilization of cholesterol oxidase in LbL films and detection of cholesterol using ac measurements

The preserved activity of immobilized biomolecules in layer-by-layer (LbL) films can be exploited in various applications. including biosensing. In this study, cholesterol oxidase (COX) layers were alternated with layers of poly(allylamine hydrochloride) (PAH) in LbL films whose morphology was investigated with atomic force microscopy (AFM). The adsorption kinetics of COX layers comprised two regimes, a fast, first-order kinetics process followed by a slow process fitted with a Johnson-Mehl-Avrami (JMA) function. with exponent similar to 2 characteristic of aggregates growing as disks. The concept based on the use of sensor arrays to increase sensitivity, widely employed in electronic tongues, was extended to biosensing with impedance spectroscopy measurements. Using three sensing units, made of LbL films of PAH/COX and PAHIPVS (polyvinyl sulfonic acid) and a bare gold interdigitated electrode, we were able to detect cholesterol in aqueous solutions down to the 10(-6) M level. This high sensitivity is attributed to the molecular-recognition interaction between COX and cholesterol, and opens the way for clinical tests to be made with low cost. fast experimental procedures. (C) 2008 Published by Elsevier B.V.

EX-SITU BIOREMEDIATION OF BRAZILIAN SOIL CONTAMINATED WITH PLASTICIZERS PROCESS WASTES

The aim of this research was to evaluate the bioremediation of a soil contaminated with wastes from a plasticizers industry, located in Sao Paulo, Brazil. A 100-kg soil sample containing alcohols, adipates and phthalates was treated in an aerobic slurry-phase reactor using indigenous and acclimated microorganisms from the sludge of a wastewater treatment plant of the plasticizers industry (11gVSS kg(-1) dry soil), during 120 days. The soil pH and temperature were not corrected during bioremediation; soil humidity was corrected weekly to maintain 40%. The biodegradation of the pollutants followed first-order kinetics; the removal efficiencies were above 61% and, among the analyzed plasticizers, adipate was removed to below the detection limit. Biological molecular analysis during bioremediation revealed a significant change in the dominant populations initially present in the reactor.

ELECTROCHEMICAL OXIDATION OF THE HERBICIDE TEBUTHIURON USING DSA (R)-TYPE ELECTRODE

ELECTROCHEMICAL OXIDATION OF THE HERBICIDE TEBUTHIURON USING DSA (R)-TYPE ELECTRODE. Tebuthiuron (TBH) is a herbicide widely used in different cultures and known for its toxic effects. Electrochemical methods are promising for removing pollutants such as pesticides. This study showed the degradation of TBH using a DSA (R) anode operated at current densities of 50 to 200 mA cm(-2). Removal presented pseudo-first order kinetics while high-pressure liquid chromatography (UV detection) showed two peaks, ascribed to degradation intermediates. The maximum percentage of total organic carbon removed was 12.9%. Ion chromatography revealed that higher concentrations of nitrate and nitrite ions formed with increasing current density.

Biorremediação de solo contaminado por isobutanol, Bis-2-etil-hexilftalato e Di-isodecilftalato

Embora os ftalatos sejam um dos poluentes mais frequentemente encontrados no meio ambiente, há escassez de dados na literatura sobre biorremediação de solos tropicais contaminados por esses compostos. Por esse motivo, este estudo avaliou a biorremediação de um solo contaminado com os plastificantes DEHP (Bis-2-etilhexilftalato), DIDP (Di-isodecilftalato) e álcool isobutílico, por uma indústria no Estado de São Paulo. A biorremediação ocorreu pela utilização de microrganismos presentes no solo e pela adição de inóculo adaptado em reator em fase de lama. O reator foi monitorado durante 120 dias, sendo corrigida apenas a umidade do solo. Os resultados indicaram que a biodegradação dos ftalatos seguiu uma cinética de primeira ordem e a biorremediação ocorreu na faixa de pH entre 7,4 e 8,4 e temperaturas entre 17 e 25 ºC, com eficiência de remoção de contaminantes acima de 70 %. Após 120 dias, o teor de DEHP estava abaixo de 4 mg kg-1, limite estipulado pela legislação brasileira para solo de uso residencial.

Oxidação eletroquímica do herbicida tebutiuron utilizando eletrodo do tipo DSA

Tebuthiuron (TBH) is a herbicide widely used in different cultures and known for its toxic effects. Electrochemical methods are promising for removing pollutants such as pesticides. This study showed the degradation of TBH using a DSA® anode operated at current densities of 50 to 200 mA cm-2. Removal presented pseudo-first order kinetics while high-pressure liquid chromatography (UV detection) showed two peaks, ascribed to degradation intermediates. The maximum percentage of total organic carbon removed was 12.9%. Ion chromatography revealed that higher concentrations of nitrate and nitrite ions formed with increasing current density.

Ex-situ bioremediation of Brazilian soil contaminated with plasticizers process wastes

The aim of this research was to evaluate the bioremediation of a soil contaminated with wastes from a plasticizers industry, located in São Paulo, Brazil. A 100-kg soil sample containing alcohols, adipates and phthalates was treated in an aerobic slurry-phase reactor using indigenous and acclimated microorganisms from the sludge of a wastewater treatment plant of the plasticizers industry (11gVSS kg-1 dry soil), during 120 days. The soil pH and temperature were not corrected during bioremediation; soil humidity was corrected weekly to maintain 40%. The biodegradation of the pollutants followed first-order kinetics; the removal efficiencies were above 61% and, among the analyzed plasticizers, adipate was removed to below the detection limit. Biological molecular analysis during bioremediation revealed a significant change in the dominant populations initially present in the reactor.

Growth kinetics of CdS in germanium oxide glassy matrix

In the present work we revisit the size data of CdS microcrystals previously collected in the glassy matrix of Germanium oxide. The CdS clusters analyzed using electron microscopy images have shown a wurtzite structure. The mean average radius, dispersion and volume evaluated from the histograms showed good agreement for t(1/3), t(2/3) and t laws, respectively. We observed that the amount of microcrystals remains constant throughout the heat treatment process, as well as that the radii distribution has a lower limit and increases with heat treatment. The distribution of radii follows a distribution similar to the Lifshitz-Slyozov-Wagner distribution limited in the origin. Discussions led to the conclusion that the growth of CdS is a process that occurs after the fluctuating nucleation and coalescence phases. We then analyze the growth process, assuming that the evaporation is overcome by the precipitation rate, stabilizing all clusters with respect to dissolution back into the matrix. The problem was simplified neglecting anisotropy and the assuming a spherical shape for clusters and particles. The low interface tension was described in terms of an empirical potential barrier in the surface of the cluster. The growth dynamics developed considering that the number of clusters remains constant, and that the minimum size of these clusters grow with time, as the first order approximation showed a good agreement with the flaw. (C) 2012 Elsevier B.V. All rights reserved.

A comparative study of the electrochemical oxidation of the herbicide tebuthiuron using boron-doped diamond electrode

The thiadiazolylurea derivative tebuthiuron (TBH) is commonly used as an herbicide even though it is highly toxic to humans. While various processes have been proposed for the removal of organic contaminants of this type from wastewater, electrochemical degradation has shown particular promise. The aim of the present study was to investigate the electrochemical degradation of TBH using anodes comprising boron-doped (5000 and 30000 ppm) diamond (BDD) films deposited onto Ti substrates operated at current densities in the range 10-200 mA cm(-2). Both anodes removed TBH following a similar pseudo first-order reaction kinetics with k(ap)p close to 3.2 x 10(-2) min(-1). The maximum mineralization efficiency obtained was 80%. High-pressure liquid chromatography with UV-VIS detection established that both anodes degraded TBH via similar intermediates. Ion chromatography revealed that increasing concentrations of nitrate ions (up to 0.9 ppm) were formed with increasing current density, while the formation of nitrite ions was observed with both anodes at current densities >= 150 mA cm(-2). The BDD film prepared at the lower doping level (5000 ppm) was more efficient in degrading TBH than its more highly doped counterpart. This unexpected finding may be explained in terms of the quantity of impurities incorporated into the diamond lattice during chemical vapor deposition. (C) 2012 Elsevier Ltd. All rights reserved.

Dilute Acid Hydrolysis of Sugar Cane Bagasse at High Temperatures: A Kinetic Study of Cellulose Saccharification and Glucose Decomposition. Part I: Sulfuric Acid as the Catalyst

The kinetics of sugar cane bagasse cellulose saccharification and the decomposition of glucose under extremely low acid (ELA) conditions, (0.07%), 0.14%, and 0.28% H2SO4, and at high temperatures were investigated using batch reactors. The first-order rate constants were obtained by weight loss, remaining glucose, and fitting glucose concentration profiles determined with HPLC using the Saeman model. The maximum glucose yields reached 67.6% (200 degrees C, 0.07% H2SO4, 30 min), 69.8% (210 degrees C, 0.14% H2SO4, 10 min), and 67.3% (210 degrees C, 0.28% H2SO4, 6 min). ELA conditions produced remarkable glucose yields when applied to bagasse cellulose. The first-order rate constants were used to calculate activation energies and extrathermodynamic parameters to elucidate the reaction mechanism under ELA conditions. The effect of acid concentration on cellulose hydrolysis and glucose decomposition was also investigated. The observed activation energies and reaction orders with respect to hydronium ion for cellulose hydrolysis and glucose decomposition were 184.9 and 124.5 kJ/mol and 1.27 and 0.75, respectively.

Development of enzymic time-temperature integrators with rapid detection for evaluation of continuous HTST pasteurization processes

The assessment of the thermal process impact in terms of food safety and quality is of great importance for process evaluation and design. This can be accomplished from the analysis of the residence time and temperature distributions coupled with the kinetics of thermal change, or from the use of a proper time-temperature integrator (TTI) as indicator of safety and quality. The objective of this work was to develop and test enzymic TTIs with rapid detection for the evaluation of continuous HTST pasteurization processes (70-85 degrees C, 10-60 s) of low-viscosity liquid foods, such as milk and juices. Enzymes peroxidase, lactoperoxidase and alkaline phosphatase in phosphate buffer were tested and activity was determined with commercial reflectometric strips. Discontinuous thermal treatments at various time-temperature combinations were performed in order to adjust a first order kinetic model of a two-component system. The measured time-temperature history was considered instead of assuming isothermal conditions. Experiments with slow heating and cooling were used to validate the adjusted model. Only the alkaline phosphatase TTI showed potential to be used for the evaluation of pasteurization processes. The choice was based on the obtained z-values of the thermostable and thermolabile fractions, on the cost and on the validation tests. (C) 2012 Elsevier Ltd. All rights reserved.

Investigation of the pore blockage of a Brazilian dolomite during the sulfation reaction

The influence of the temperature and reaction time on the sulfation process of a dolomite is investigated in this paper. The sulfation effectiveness was evaluated and correlated with changes in the physical characteristics of a Brazilian dolomite during the reactive process. Calcination and sulfation experiments were performed under isothermal conditions for dolomite samples with average particle sizes of 545 mu m at temperatures of 750 degrees C, 850 degrees C and 950 degrees C at different times of sulfation. Thermogravimetric tests were applied to establish the reactivity variation of the dolomite in function of the time in the sulfation reaction and evaluate the methodology of the samples preparation. Porosimetry tests were performed to study the pore blockage of dolomite during the sulfation reaction. The highest values of BET surface area were 25.55 m(2)/g, 29.55 m(2)/g and 12.62 m(2)/g for calcined samples and after their sulfation processes, conversions of 51.5%, 61.9% and 42.8% were obtained at 750 degrees C, 850 degrees C and 950 degrees C, respectively. Considering the process as a whole, the best fit was provided by a first-order exponential decay equation. Moreover, the results have shown that it is possible to quantify the decreasing in the dolomite reactivity for sulfur dioxide sorption and understand the changes in the behavior of the sulfation process of limestones when applied to technologies, as fluidized bed combustor, in which sulfur dioxide is present. (C) 2011 Elsevier B. V. All rights reserved.

Integration of processes induced air flotation and photo-Fenton for treatment of residual waters contaminated with xylene

Produced water in oil fields is one of the main sources of wastewater generated in the industry. It contains several organic compounds, such as benzene, toluene, ethyl benzene and xylene (BTEX), whose disposal is regulated by law. The aim of this study is to investigate a treatment of produced water integrating two processes, i.e., induced air flotation (IAF) and photo-Fenton. The experiments were conducted in a column flotation and annular lamp reactor for flotation and photodegradation steps, respectively. The first order kinetic constant of IAF for the wastewater studied was determined to be 0.1765 min(-1) for the surfactant EO 7. Degradation efficiencies of organic loading were assessed using factorial planning. Statistical data analysis shows that H2O2 concentration is a determining factor in process efficiency. Degradations above 90% were reached in all cases after 90 min of reaction, attaining 100% mineralization in the optimized concentrations of Fenton reagents. Process integration was adequate with 100% organic load removal in 20 min. The results of the integration of the IAF with the photo-Fenton allowed to meet the effluent limits established by Brazilian legislation for disposal. (C) 2011 Elsevier B.V. All rights reserved.