Batch treatment of saline wastewater by Halanaerobium lacusrosei in an anaerobic packed bed reactor

BACKGROUND: This study considers batch treatment of saline wastewater in an upflow anaerobic packed bed reactor by salt tolerant anaerobic organisms Halanaerobium lacusrosei . RESULTS: The effects of initial chemical oxygen demand (COD) concentration (COD₀ = 1880–9570 mg L^?1), salt concentration ([NaCl] = 30–100 g L^?1) and liquid upflow velocity (V_up = 1.0–8.5 m h^?1) on COD removal from salt (NaCl)‐containing synthetic wastewater were investigated. The results indicated that initial COD concentration significantly affects the effluent COD concentration and removal efficiency. COD removal was around 87% at about COD₀ = 1880 mg L^?1, and efficiency decreased to 43% on increasing COD₀ to 9570 mg L^?1 at 20 g L^?1 salt concentration. COD removal was in the range 50–60% for [NaCl] = 30–60 g L^?1 at COD₀ = 5200 ± .100 mg L^?1. However, removal efficiency dropped to 10% when salt concentration was increased to 100 g L^?1. Increasing liquid upflow velocity from V_up = 1.0 m h^?1 to 8.5 m h^?1 provided a substantial improvement in COD removal. COD concentration decreased from 4343 mg L^?1 to 321 mg L^?1 at V_up = 8.5 m h^?1, resulting in over 92% COD removal at 30 g L^?1 salt‐containing synthetic wastewater. CONCLUSION: The experimental results showed that anaerobic treatment of saline wastewater is possible and could result in efficient COD removal by the utilization of halophilic anaerobic bacteria. Copyright © 2008 Society of Chemical Industry     

Earthquake Response Spectra Models Incorporating Fuzzy Logic with Statistics

It is well accepted that the ground motion at a site depends on the rupture mechanism, source-to-site distance, local geologic conditions, and energy released by the earthquake. However, design spectra represent expected responses that do not explicitly include the influence of the uncertainties associated with these fundamental features. The objective of this article is to present a viable methodology that can be used to develop a response spectra using fuzzy logic and statistical analysis and to demonstrate how fuzzy-statistical response spectra can be used to evaluate potential structural response.
Site-specific response spectra from the Northridge earthquake are used to develop response spectra models that quantify uncertainties inherent to the ground motion. The uncertainty in these computational models is quantified using fuzzy-set logic, statistics, and random vibrations. The local geologic conditions are characterized as rock or alluvium, and fuzzy sets are used to represent near, intermediate, and far epicentral distances. Proposed ground-motion models are used to define uncertain input motion for use in dynamic analyses of an example building. The resulting structural responses are compared with those obtained from time-dependent accelerations. Comparisons are made with the current design codes, and suggested implementation strategies for the proposed models are discussed.     

Effects of distribution of lightweight aggregates on internal curing of concrete

This study investigates the effects of spatial distribution of lightweight aggregates (LWAs) on internal curing of concrete. As replacements for normal aggregates, different sizes and amounts of natural pumice LWAs were used as water reservoirs to provide internal curing in mitigating autogenous deformation. Water in the pre-soaked LWAs flows into cement paste during hydration and provides internal curing to counteract the RH loss due to self-desiccation of binding paste. The results show that variations in the autogenous strain of concrete can be evaluated in terms of LWA–LWA proximity. The protected paste volume approach, previously used for air-entrained concrete, is applied to calculate the internally-cured volume of paste. The results show that the experimental rate of mitigation of autogenous strain for different series of concrete specimens, with respect to the reference concrete, gave the best-fitted values at water flow distance of 1 mm. The results indicate that the protected paste volume in internal curing can be determined by calculating the water-entrained volume using image analysis.     

Allele-specific genotype detection of factor V Leiden mutation from polymerase chain reaction amplicons based on label-free electrochemical genosensor

An electrochemical genosensor for the genotype detection of allele-specific factor V Leiden mutation from PCR amplicons using the intrinsic guanine signal is described. The biosensor relies on the immobilization of the 21-mer inosine-substituted oligonucleotide capture probes related to the wild-type or mutant-type amplicons, and these probes are hybridized with their complementary DNA sequences at a carbon paste electrode (CPE). The extent of hybridization between the probe and target sequences was determined by using the oxidation signal of guanine in connection with differential pulse voltammetry (DPV). The guanine signal was monitored as a result of the specific hybridization between the probe and amplicon at the CPE surface. No label-binding step was necessary, and the appearance of the guanine signal shortened the assay time and simplified the detection of the factor V Leiden mutation from polymerase chain reaction (PCR)-amplified amplicons. The discrimination between the homozygous and heterozygous mutations was also established by comparing the peak currents of the guanine signals. Numerous factors affecting the hybridization and nonspecific binding events were optimized to detect down to 51.14 fmol/mL target DNA. With the help of the appearance of the guanine signal, the yes/no system is established for the electrochemical detection of allele-specific mutation on factor V for the first time. Features of this protocol are discussed and optimized.     

A scatter search-based heuristic to locate capacitated transshipment points

We consider a fixed charge two-stage location problem in which a given number of intermediate transshipment points are to be located between the supply plants and the customer locations. Both plants and transshipment points are capacitated. Scatter search is a population-based heuristic that has been applied to several combinatorial optimization problems. We develop an efficient scatter search-based heuristic approach with hybrid improvements including local search and path-relinking routines. Computational results demonstrate the effectiveness of the heuristic even for realistic problems with larger instances and tighter capacities.     

Biohydrogen production by extracted fermentation from sugar beet

In the study, the production of biohydrogen by extracted fermentation from sugar beet was evaluated. Effects of initial amount of sugar beet, biomass and particle size of sugar beet on biohydrogen formation were investigated. The hydrogen (H₂) gas was predicted to be 78.6 mL at initial dry weight of sugar beet 24.6 g L^?1 and H₂ yield was calculated as 81.9 mLH₂ g^?1TOC while biomass concentration (1 g L^?1) and particle size (0.3 cm) were constant. The peak H₂ gas volume was predicted to be 139.9 mL at the low particle size of 0.1 cm. Hydrogen gas production potential was predicted as 143.6 mL h^?1. The peak value of 197.9 mLH₂ g^?1TOC was obtained with particle size of 0.1 cm when dry weight of sugar beet and initial amount of biomass was kept constant at 24.6 g L^?1 and 1 g L^?1, respectively.     

Hydrogen production by autothermal reforming of LPG for PEM fuel cell applications

Indirect partial oxidation, or oxidative steam reforming, tests of a bimetallic Pt–Ni catalyst supported on δ$\delta$-alumina were conducted in propane–n  -butane mixtures (LPG) used as feed. _H2${\mathrm{H}}_2$ production activity and _H2/CO${\mathrm{H}}_2/\mathrm{CO}$ selectivity were investigated in response to different S/C, C/_O2$\mathrm{C}/{\mathrm{O}}_2$ and W/F ratios. It was confirmed that higher steam content in the reactant stream increases both the activity and the _H2/CO${\mathrm{H}}_2/\mathrm{CO}$ selectivity of the process. Low residence times created a positive impact on catalyst activity not only for hydrogen but also for carbon monoxide production due to the increased amount of fresh hydrocarbon in the feed stream. Hence, the highest selectivity level was obtained at intermediate residence times. The response of the system to C/_O2$\mathrm{C}/{\mathrm{O}}_2$ ratio was found to depend on the available steam content due to the complex nature of IPOX. The Pt–Ni catalyst was very prone to catalyst deactivation at low S/C ratios accompanied by high C/_O2$\mathrm{C}/{\mathrm{O}}_2$ ratios, but this problem was not encountered at high S/C ratios. A comparison of catalyst performance for different propane-to-n-butane ratios in the LPG feed indicated that the Pt–Ni catalyst has slightly better activity and selectivity at higher n-butane contents at the expense of becoming more sensitive to coke deposition.     

An efficient interface model to develop scalable methodology of melt processing of polypropylene with graphene oxide produced by an improved and eco-friendly electrochemical exfoliation

This study developed a scalable and straightforward adaptation methodology for melt processing of polypropylene (PP) to provide a high degree of exfoliation of multilayer graphene oxide (GO) by using a high-shear mixer. GO was first produced by an improved and eco-friendly electrochemical exfoliation by using an environmentally friendly aqueous methanesulfonic acid (MSA) and a sodium sulfate salt system to minimize the environmental impact. The produced GOs then were melt blended with PP and their mechanical, thermal, and morphological properties were investigated under different GO loadings to attain ideal configuration and increase interfacial interactions between polymer matrix and reinforcer. Comparisons were made by producing different PP composites using two different GO types produced in salt and acid environments. Additionally, by applying different voltages to salt system, the effect of applied voltage on the properties of both GO material and the composites were discussed. The characterization results indicated that GO obtained in MSA solution caused a 71% increase in flexural modulus and 46% in flexural strength with the addition of 1 wt% GO. The rheological characterization also showed that dispersion and viscosity improved with lower GO loadings compared to neat polymer by providing cost-effective and scalable graphene manufacturing.     

Formalisms for query capture and data source identification to support data fusion for construction productivity monitoring

Productivity monitoring, which involves frequent monitoring and analysis of on-going construction activities, helps in assessing a project's performance and in enabling identification of opportunities for improvement. It often involves finding answers for dynamic user queries that require data to be fused from different combinations of heterogeneous data sources having different levels of detail, representations and reference systems. Digital elements of these sources are expanding exponentially, and yet fusing and processing them manually remains a challenging problem. In this paper, the authors present a formal approach for capturing dynamic user queries and identifying applicable sets of data sources from a given set of available data sources to answer such queries. This approach is an important step to enable automated and efficient multi-source data fusion.