Fenton and Electro-Fenton Methods for Oxidation of H-Acid and Reactive Black 5

Oxidative treatment of H-acid (HA) and Reactive Black 5 (RB5) using Fenton reagent (Fe2+/H2O2) and the electro-Fenton (EF) method is reported. Optimization of doses of ferrous iron and hydrogen peroxide was carried out in each case using HA; and the oxidation of RB5 was also carried out under the optimized conditions. Approximately 71% chemical oxygen demand (COD) was removed in 2 h using the conventional Fenton method at optimized doses: Fe2+ = 0.3?g/L (5.37 mM), H2O2 = 6?mL/L (53.0 mM), H2O2/Fe2+ = 10. In contrast, more than 92% COD was removed in 15 min using the EF method with an optimized Fe2+ dose of 0.130?g/L (2.34 mM) and 8?ml/L (70.6 mM) of H2O2. The pseudo-first-order rate constants (k) for the Fenton reagent and EF method were 0.054 and 0.38?min?1. The COD removal through the EF method was seven times faster. The calculated energy requirement of the EF method was 0.82?kg?COD/kW?h at the minimum applied current (0.25 A) when approximately 92.5% COD was removed. In the case of RB5, about 67 and 87% COD was removed under optimized Fenton and electro-Fenton conditions, respectively. The higher efficiency of the EF method was attributed to incremental addition of Fe2+ and accompanying higher H2O2/Fe2+ molar ratio. The results are discussed in the light of the mechanism for Fenton’s oxidation.     

Ergonomics, gerontechnology, and design for the home-environment

An ergonomic approach could improve the quality of life and activities in daily living. Gerontechnology reduces the effects of age-related impairments with technological devices and particular design for the home-environment. Physiological decline with increasing age renders the daily activities at home more difficult. This paper highlights some "common sense" and specific design suggestions in the entrance and kitchen, aimed to increase the self-sufficiency of elderly people. We suggest that gerontechnology may have a particular role in the improvement of comfort and safety for aged people.     

Determining Hydraulic Characteristics of Production Wells using Genetic Algorithm

Proper well management requires the determination of characteristic hydraulic parameters of production wells such as well loss coefficient (C) and aquifer loss coefficient (B), which are conventionally determined by the graphical analysis ofstep-drawdowntest data. However, in the present study, the efficacy of a non-conventional optimization technique called Genetic Algorithm (GA), which ensures near-optimal or optimal solutions, is assessedin determining well parameters from step-drawdown test data. Computer programs were developed to optimize the well parametersby GA technique for two cases: (i) optimization of B and C only, and (ii) optimization of B, C and p (exponent) as well as to evaluate the well condition. The reliability and robustness of the developed computer programs were tested usingnine sets of published and unpublished step-drawdown data from varying hydrogeologic conditions. The well parameters obtained by the GA technique were compared with those obtained by the conventional graphical method in terms of root mean square error(RMSE) and visual inspection. It was revealed that the GA technique yielded more reliable well parameters with significantlylow values of RMSE for almost all the datasets, especially in caseof three-variable optimization. The optimal values of the parametersB, C and p for the nine datasets were found to range from 0.382 to 2.292 min m^-2, 0.091 to 3.262, and 1.8 to 3.6, respectively. Because of a wide variation of p, the GA techniqueresulted in considerably different but dependable and robust well parameters as well as well specific capacity and well efficiency compared to the graphical method. The condition of three wells was found to be good, one well bad and that of the remaining five wells satisfactory. The performance evaluation of the developed GA code indicated that a proper selection of generation number and population size is essential to ensure efficient optimization. Furthermore,a sensitivity analysis of the obtained optimal parameters demonstrated that the GA technique resulted in a unique set ofthe parameters for all the nine datasets. It is concluded thatthe GA technique is an effective and reliable numerical tool for determining the characteristic hydraulic parameters of production wells.     

Increasing coverage to improve detection of network and host anomalies

For intrusion detection, the LERAD algorithm learns a succinct set of comprehensible rules for detecting anomalies, which could be novel attacks. LERAD validates the learned rules on a separate held-out validation set and removes rules that cause false alarms. However, removing rules with possible high coverage can lead to missed detections. We propose three techniques for increasing coverage—Weighting, Replacement and Hybrid. Weighting retains previously pruned rules and associate weights to them. Replacement, on the other hand, substitutes pruned rules with other candidate rules to ensure high coverage. We also present a Hybrid approach that selects between the two techniques based on training data coverage. Empirical results from seven data sets indicate that, for LERAD, increasing coverage by Weighting, Replacement and Hybrid detects more attacks than Pruning with minimal computational overhead.     

Scheduling UET-UCT tasks: branch-and-bound search in the priority space

The paper is concerned with the problem of scheduling partially ordered unit execution time tasks on parallel processors with unit communication delays and release times. Two criteria are considered, the maximum lateness and its particular case, the makespan. This problem plays an important role in scheduling theory and was originally inspired by the applications to multi-processor computer systems. It is well known that for both criteria the problem is NP-hard in the strong sense. The paper presents an implementation of the branch-and-bound method which does not partition the feasible region explicitly. The theoretical results are complemented by computational experiments.     

Homogeneous charge compression ignition of binary fuel blends

The present experimental investigation aims to understand the homogeneous combustion chemistry associated with binary blends of three surrogate components for practical fuels, including toluene, isooctane, and diisobutylene-1 (DIB-1). Specifically, high-pressure autoignition characteristics of the three neat fuel components as well as the fuel blends of toluene + isooctane and toluene + DIB-1 are studied herein. Experiments are conducted in a rapid compression machine at compressed pressures varying from 15 to 45 bar and under low to intermediate temperatures. To obtain insights into interactions among fuels, the relative proportion of the two neat fuels in the reactive mixtures is systematically varied, while the total fuel mole fraction and equivalence ratio are kept constant. Experimental results demonstrate that ignition delays for neat toluene are more than an order of magnitude longer than those for neat isooctane. Whereas DIB-1 has ignition delays shorter than those for isooctane at higher temperatures, at temperatures lower than 820 K DIB-1 shows a longer ignition delay. Although the ignition delays of binary blends lie in between the two extremes of neat components, the variation of ignition delay with the relative fuel proportion is seen to be highly nonlinear. Especially, a small addition of isooctane or DIB-1 to toluene can result in greatly enhanced reactivity. In addition, the effect of DIB-1 addition to toluene is more significant than the effect of isooctane addition. Furthermore, in the compressed temperature range from 820 to 880 K, ignition delay of the toluene + isooctane blend shows greater sensitivity to temperature than that of isooctane.     

Prototyping bio-nanorobots using molecular dynamics simulation and virtual reality

This paper presents a molecular mechanics study using a molecular dynamics software (NAMD) coupled to virtual reality (VR) techniques for intuitive bio-nanorobotic prototyping. Using simulated bio-nano environments in VR, the operator can design and characterize through physical simulation and 3D visualization the behavior of protein-based components and structures. The main novelty of the proposed simulations is based on the characterization of stiffness performances of passive joints-based proteins (α-helix deca-alanine, repressor of primer protein and immunoglobulin protein) and active joints-based viral protein motor (VPL) in their native environment. Their use as elementary bio-nanorobotic components are also simulated and the results discussed.     

Interpretation of experimental data from rapid compression machines without creviced pistons

Over the last two decades, experimental data of the nature of species evolution profiles and ignition delays from rapid compression machines (RCMs) has been used to develop and validate chemical kinetic mechanisms at low-to-intermediate temperatures and elevated pressures. A significant portion of this overall dataset is from RCMs that had not employed a creviced piston to contain the roll-up vortex. The detrimental influence of the roll-up vortex and the thermokinetic interactions due to the resulting temperature non-homogeneity during the negative temperature coefficient (ntc) regime have been documented in the literature. However, the adequacy of the homogeneous modeling of RCMs without creviced pistons during reactive conditions has not been investigated. In this work, computational fluid dynamics simulations of an RCM without a creviced piston are conducted for autoignition of n-heptane over the entire ntc regime over a range compressed pressures from 5 to 18 bar. The results from the CFD simulations highlight the non-homogeneity of autoignition and reveal significant quantitative discrepancy in comparison to homogeneous modeling, particularly for the hot ignition delay in the ntc regime. Specifically, the roll-up vortex induced temperature non-homogeneity leads to diminution of the ntc behavior. The experimental data from RCMs without creviced piston needs to be taken with caution for quantitative validation and refinement of kinetic mechanism, particularly at conditions when ntc behavior is highly pronounced.     

Nitrous oxide emission and ammonia volatilization induced by vinasse and N fertilizer application in a sugarcane crop at Rio de Janeiro,Brazil

In Brazilian sugarcane plantations, fertilization with vinasse, supplemented or not with mineral fertilizer, is a common practice. But little is known about the effects of this application on N losses, especially those forms of N which give rise to greenhouse gas emissions. The aim of this study was to quantify N₂O and NH₃ emissions from soil after vinasse application and urea fertilizer addition and to examine the possible impact adding vinasse before or after urea. Two experiments were conducted under greenhouse conditions and one in the field with treatments of vinasse and urea fertilizer, either alone, or in sequence. The highest proportions of N emitted as N₂O were registered in the vinasse treatment, which amounted to 15 % of the N applied in the first greenhouse experiment, and 2.5 % in the field experiment. With respect to the losses by NH₃ volatilization, urea was the only treatment where this process was significant. N₂O emission from vinasse was 2.5 %, somewhat above the default emission factor of 1 % of the IPCC. N₂O emissions from urea were also variable, but emission factors registered were still well below the default IPCC factor for organic residues. The order of addition of urea and vinasse had little effect on NH₃ volatilization in the field, but there were evidences it was important for N₂O.