Kinetic study on photocatalytic degradation of Acid Orange 52 in a baffled reactor using TiO2 nanoparticles

In this study, a baffled photocatalytic reactor was used for the treatment of colored wastewater containing the azo dye of Acid Orange 52(AO52). A study on the active species of the photocatalytic process using TiO_2 nanoparticles indicated that hydroxyl radical and superoxide have the greatest contribution to the dye degradation process respectively.Given that a level of biological oxygen demand/chemical oxygen demand(BOD5/COD) equal to 0.4 was achieved after about 5 hr from the beginning of the experiment, the reactor seems to be capable of purifying the wastewater containing AO52 dye after this time in order to discharge into a biological treatment system to continue the treatment process.The results of the liquid chromatography-mass spectrometry(LC-MS) test showed that during the first 4 hr of the experiment, with the breakdown of the azo bond, the contaminant was decomposed into the benzene annular compounds with less toxicity indicating a reduction in the toxicity of wastewater after removing the dye agent. The study on the kinetics of these reactions followed the pseudo-first-order kinetic model in all conditions and corresponded well to Langmuir–Hinshelwood model. According to the kinetic model for the simultaneous occurrence of possible pathways, the kinetic constant of production and degradation of intermediate products in optimal conditions was estimated to be between 0.0029 and 0.0391 min~(-1).     

Improvement of production of lipopeptide antibiotic iturin A using fish protein

To enhance the production of lipopeptide antibiotic iturin A, nutrient contents of the culture mediums were investigated in both submerged and biofilm fermentations. As a carbon source maltose and as nitrogen source, fish protein was used. In submerged fermentation maltose uptake was found lower (12%) compared to biofilm fermentation (15%) that was associated with higher cellular growth in biofilm. However, requirement of nitrogen (fish protein) concentration was found similar in both submerged and biofilm fermentations. Production of iturin A in submerged fermentation with 12% maltose and 5% fish protein was 4450 mg/L, and in biofilm fermentation it was 5050 mg/L when 15% maltose and 5% fish protein was used.     

Integration of counter-current relative permeability in the simulation of CO2 injection into saline aquifers

Carbon dioxide (CO₂) injection into saline aquifers is one of the promising options to sequester large amounts of CO₂ in geological formations. During as well as after injection of CO₂ into an aquifer, CO₂ migrates towards the top of the formation due to density differences between the formation brine and the injected CO₂. The time scales of CO₂ migration towards the top of an aquifer and the fraction of CO₂ that is trapped as residual gas depends strongly on the driving forces that are acting on the injected CO₂.When CO₂ migrates to the top of an aquifer, brine may be displaced downwards in a counter-current flow setting particularly during the injection period. A majority of the published work on counter-current flow settings have reported significant reductions in the associated relative permeability functions as compared to co-current measurements. However, this phenomenon has not yet been considered in the simulation of CO₂ storage into saline aquifers.In this paper we study the impact of changes in mobility for the two-phase brine/CO₂ system as a result of transitions between co- and counter-current flow settings. We have included this effect in a simulator and studied the impact of the related mobility reduction on the saturation distribution and residual saturation of CO₂ in aquifers over relevant time scales. We demonstrate that the reduction in relative permeability in the vertical direction changes the plume migration pattern and has an impact on the amount of gas that is trapped as a function of time. This is to our best knowledge the first attempt to integrate counter-current relative permeability into the simulation of injection and subsequent migration of CO₂ in aquifers. The results and analysis presented in this paper are directly relevant to all ongoing activities related to the design of large-scale CO₂ storage in saline aquifers.     

Environmental exposure to POPs and heavy metals in urban children from Dhaka, Bangladesh

Persistent organic pollutants (POPs) and heavy metals are well known environmental pollutants. Even though numerous studies have been carried out to assess human exposures to these compounds, there is still a lack of data on humans from developing countries, especially in underprivileged children. The objective of this study was to assess the exposure to POPs and heavy metals in children from Dhaka, Bangladesh. One specific aim was to investigate whether children working at, or living close to, open waste disposal sites (WDSs) were more heavily exposed than other urban children. In 2008, blood and serum were collected from 73 children aged 7-16 from five neighbourhoods. Some of the children lived and worked at WDSs (N = 31), others lived next to a WDS (N = 17), whereas some children lived far from such sites (N = 25). Blood levels of lead (B-Pb), cadmium (B-Cd), and selenium (B-Se) were determined by ICP-MS for all subjects. The metal levels were high, with B-Pb overall mean 120 μg L(-1) (range 40-220), B-Cd 0.74 μg L(-1) (0.22-4.1), and B-Se 120 μg L(-1) (81-170). There were no marked differences between children from the different neighbourhoods, or between WDS workers and other children. PCB levels were low and with no contrast between neighbourhoods, for CB-153 the overall mean was 7.0 ng g(-1) fat (2.8-51). In contrast, high levels of DDTs were observed in all children, for 4,4'-DDE 1300 ng g(-1) fat (420-4600), and for 4,4'-DDT 326 ng g(-1) fat (44-1400), indicating ongoing exposure. PBDE levels were low, and BDE-209 was quantitated mainly in children working at or living close to WDSs. In conclusion, the high levels of DDTs, lead and cadmium observed in children from Dhaka are of concern. Many children were exposed at levels where health effects have been observed, or at levels without safety margins.     

Comparison of steel,aluminum and composite bonnet in terms of pedestrian head impact

Material selection for automotive closures is influenced by different factors such as cost, weight and structural performance. Among closures, the automotive bonnet must fulfill the requirements of pedestrian safety which is evaluated by child and adult headform impactors. The mechanisms of injury are complex, therefore; the Head Injury Criterion (HIC) which shows a measure of the likelihood of head injury arising from an impact is developed. HIC includes the effects of head acceleration and the duration of the acceleration.In this paper a new finite element model has been developed which is capable to simulate head impact phenomenon between headform impactors and composite bonnet. Then the behavior of three identical bonnets made of steel, aluminum and composite have been investigated by the developed model. It is shown that the energy absorption of aluminum bonnet is smaller than steel and composite ones and for keeping the aluminum bonnet at the same level of stiffness, it is necessary to increase the thickness. Therefore, the aluminum bonnet needs a larger space between the bonnet and the parts in the engine compartment. It is shown that although the displacement of headform for composite bonnet is more than that of steel and aluminum ones, but the amount of HIC’s, which are measured at the collision points are much less than those measured at the same collision points for steel and aluminum bonnets.In addition the comparison of three bonnets of the different materials has been done to highlight cost, weight, and structural performance issues.     

An adaptive neural network algorithm for assessment and improvement of job satisfaction with respect to HSE and ergonomics program: The case of a gas refinery

Researchers have been continuously trying to improve human performance with respect to Health, Safety and Environment (HSE) and ergonomics (hence HSEE). This study proposes an adaptive neural network (ANN) algorithm for measuring and improving job satisfaction among operators with respect to HSEE in a gas refinery. To achieve the objectives of this study, standard questionnaires with respect to HSEE are completed by operators. The average results for each category of HSEE are used as inputs and job satisfaction is used as output for the ANN algorithm. Moreover, ANN is used to rank operators performance with respect to HSEE and job satisfaction. Finally, Normal probability technique is used to identify outlier operators. Moreover, operators with inadequate job satisfaction with respect to HSEE are identified. This would help managers to see if operators are satisfied with their jobs in the context of HSEE. This is the first study that introduces an integrated ANN algorithm for assessment and improvement of human job satisfaction with respect to HSEE program in complex systems.     

Integrated real-time monitoring system to investigate the hypoxia in a shallow wind-driven bay

Corpus Christi Bay (Texas, USA) is a shallow wind-driven bay which experiences hypoxia (dissolved oxygen < 2 mg/L) during the summer. Since this bay is a very dynamic system, the processes that control the hypoxia can last on the order of hours to days. Monitoring systems installed on a single type of platform cannot fully capture these processes at the spatial and temporal scales of interest. Therefore, we have integrated monitoring systems installed on three different platform types: (1) fixed robotic, (2) mobile, and (3) remote. On the fixed robotic platform, an automated profiler system vertically moves a suite of water quality measuring sensors within the water column for continuous measurements. An integrated data acquisition, communication and control system has been configured on our mobile platform (research vessel) for synchronized measurements of hydrodynamic and water quality parameters at greater spatial resolution. In addition, a high-frequency radar system has been installed on remote platforms to generate surface current maps for the bay. With our integrated system, we were able to capture evidence of a hypoxic event in summer 2007; moreover, we detected low dissolved oxygen conditions in a part of the bay with no previously reported history of hypoxia.     

Characterization of Active Polybutylene Succinate Films Filled Essential Oils for Food Packaging Application

Journal of Polymers and the Environment - The development of active packaging for food applications have been increasingly favorable in publicity, industry, and research field, by attributing to...     

Optimization of Xanthan Gum/Poly(acrylic acid)/Cloisite 15A Semi-IPN Hydrogels for Heavy Metals Removal

Journal of Polymers and the Environment - Semi-interpenetrating networks (semi-IPNs) of Xanthan gum/poly (acrylic acid) containing Cloisite 15A were prepared via radical polymerization using a...     

Effect of Curing Temperature on Mechanical Properties of Bio-phenolic/Epoxy Polymer Blends

Journal of Polymers and the Environment - Nowadays, researchers continue studies for alternative materials to replace the redundant petroleum-based products. The combination of various polymer...