Prioritization of subwatersheds based on flooding conditions using hydrological model,multivariate analysis and remote sensing technique

Prioritization of watersheds has gained more importance in natural resources management, particularly in the context of watershed management. Flooding potential is one of the main indices used to prioritize watersheds. The objective of this study is to investigate the Pol‐Doab Shazand Watershed flooding conditions as a result of land use change and prioritization of its subwatersheds using rainfall – runoff data. For this purpose, after computation of design flow with different return periods, factor analysis technique was applied to determine the best flow with proper return period towards evaluation and prioritization of subwatersheds. The results showed that the design flow with 25‐year return period (Q25) is suitable. The results indicate that subwatershed 22 is the highest priority because of large changes in peak flow, and subwatershed 2 given the lowest priority since changes in peak flow is the lowest.     

Time and cost efficient biodegradation of diesel in a continuous‐upflow packed bed biofilm reactor and effect of surfactant GAELE

BACKGROUND: Biodegradation of diesel hydrocarbons using bioreactors has been proposed as an alternative for diesel contaminated sites remediation. To make this alternative feasible, several factors must be optimized or improved: reducing hydraulic retention times (HRT) and applying design methods to enhance the access of the microorganisms to low soluble and recalcitrant compounds like hydrocarbon fuels. In the present work a time and cost efficient continuous‐flow packed bed bioreactor at low HRT was designed and evaluated. The effect of non‐previously studied anionic surfactant GAELE (glycolic acid ethoxylate lauryl ether) was also investigated. RESULTS: A continuous‐upflow packed bed bioreactor (CPR) was built using an inexpensive support made of volcanic and alluvial stones. The biodegradation experiments conducted with a 12‐month‐old biofilm at a fixed HRT of 0.5 h, recorded removal of up to 97.9% at a diesel concentration of 1120 mg L^?1 with GAELE. A first‐order rate constant of 0.10 h^?1 was calculated. Kinetic analysis using Arvin's model, which introduces mass transfer to the biofilm, showed statistical differences in the kinetic rate parameters (P < 0.001). Moreover, GAELE significantly increased biodegradability at high concentrations, with BOD₅ and COD removals up to 90.8 and 80.7%, respectively. Putative hydrocarbon degrading bacteria responsible for the degradation under nitrate‐reducing conditions were positively identified. CONCLUSIONS: The continuous‐upflow packed bed reactor was capable of high percentage diesel biodegradation at short HRTs. The use of GAELE increased diesel availability and thus enhanced hydrocarbon removal. Therefore, CPR packed with volcanic and alluvial stones combined with GAELE showed potential for the remediation of diesel‐impacted sites. Copyright © 2012 Society of Chemical Industry     

Quasi-static consideration of high-frequency modes for more efficient flexible multibody simulations

A number of sets of modes, for example eigenmodes, constraint modes, inertia-relief attachment modes, may be used to describe the linear elastic deformation of a flexible body in multibody dynamics. It is always possible to transform modes so that the conditions of the Buckens-frame are fulfilled. The latter frame leads to serious simplifications in the equations of motion, but cannot avoid a coupling between the body’s rotational rigid body motion and its elastic deformation. In the present paper the deformation modes will be subdivided into low- and high-frequency modes. It will be shown that the latter-mentioned coupling effect of the second ones can be safely neglected in comparison with the first ones. Consequently, the high-frequency components can be removed from time integration at all, which leads to significant savings of computational effort while the accuracy regarding the body’s deformation remains almost the same. In the case of a known frequency content of external excitation, an algorithm is given so that the available modes can be automatically separated into such low- and high-frequency modes. While the number of low-frequency modes remains more or less constant, there is a significant trend to use an increased number of high-frequency modes. Examples are moving loads (e.g., guidance) or distributed loads as they occur in contact problems or when fluid pressure is acting on surfaces. A final numerical example is given in order to demonstrate the potential of the proposed method.     

Realization of solution processed multi-layer bulk heterojunction organic solar cells by electro-spray deposition

Electro-spray deposition (ESD) was applied to fabricate solution processed donor–acceptor bulk heterojunction organic photovoltaic devices with multi-layer structure. Solvent effect was observed when using different organic solvents. Power conversion efficiency (PCE) of the devices prepared from dichlorobenzene increased dramatically comparing to the ones from chloroform, owing to improved homogeneity of the films. ESD enabled us to fabricate solution processed multi-layer (donor/donor:acceptor/acceptor) devices with simple successive deposition steps. Energy Dispersive X-ray Reflectometry analysis confirmed distinct three layered structure of the active layers. Solar cell device parameters of the trilayer devices were compared to single layer devices and those of spin coated devices with the same donor:acceptor ratio and film thickness. Post-thermal treatment results showed that after annealing at 125 °C, trilayer devices exhibited best performance with the maximum PCE of 2.17%.     

Phenolic constituents,antioxidant and antimicrobial activities of rosy garlic (Allium roseum var. odoratissimum)

The methanol extracts of leaves, flowers, stalks and bulbs of the North African endemic Allium roseum var. odoratissimum were analyzed for their phenolic profiles and screened for their antioxidant and antibacterial activities. Colourimetric analysis revealed that the highest levels of total phenols content (TPC) and total flavonoids content (TFC) were found in the flowers and leaves. The use of HPLC-PDA-MS allowed the identification of kaempferol 3,7-di-O-rhamnoside, kaempferol-3-Glucuronide, kaempferol-3-O-glucoside, kaempferol-3-O-beta-d-glucoside-7-O-alpha-l-rhamnoside, luteoline and apigenine, while four components remained unidentified. The flowers and leaves were found to possess the highest antioxidant activity with the exception in metal chelating ability. Antibacterial assay showed that Enterococcus feacium was the most susceptible bacterial strain and the stalk extract had the most effect in the inactivation of Staphylococcus aureus, Enterococcus feacium, Bacillus subtilis and Escherichia coli. Conclusively, this study allows a clear chemical differentiation between A. roseum var. odoratissimum and the other Allium species.     

Secreted,receptor-associated bone morphogenetic protein regulators reduce stochastic noise intrinsic to many extracellular morphogen distributions

Morphogens are secreted molecules that specify cell-fate organization in developing tissues. Patterns of gene expression or signalling immediately downstream of many morphogens such as the bone morphogenetic protein (BMP) decapentaplegic (Dpp) are highly reproducible and robust to perturbations. This contrasts starkly with our expectation of a noisy interpretation that would arise out of the experimentally determined low concentration (approximately picomolar) range of Dpp activity, tight receptor binding and very slow kinetic rates. To investigate mechanisms by which the intrinsic noise can be attenuated in Dpp signalling, we focus on a class of secreted proteins that bind to Dpp in the extracellular environment and play an active role in regulating Dpp/receptor interactions. We developed a stochastic model of Dpp signalling in Drosophila melanogaster and used the model to quantify the extent that stochastic fluctuations would lead to errors in spatial patterning and extended the model to investigate how a surface-associated BMP-binding protein (SBP) such as Crossveinless-2 (Cv-2) may buffer out signalling noise. In the presence of SBPs, fluctuations in the level of ligand-bound receptor can be reduced by more than twofold depending on parameter values for the intermediate transition states. Regulation of receptor–ligand interactions by SBPs may also increase the frequency of stochastic fluctuations providing a separation of timescales between high-frequency receptor equilibration and slower morphogen patterning. High-frequency noise generated by SBP regulation is easily attenuated by the intracellular network creating a system that imitates the performance of a simple low-pass filter common in audio and communication applications. Together, these data indicate that one of the benefits of receptor–ligand regulation by secreted non-receptors may be greater reliability of morphogen patterning mechanisms.     

Using data envelopment analysis in comparing the environmental performance and technical efficiency of selected companies in their global petroleum operations

This study examined the environmental performance and economic efficiency of global operations of selected companies in the petroleum industry by analyzing the technical and technical efficiency. The selected companies were chosen from the 2008 GLOBAL 500 in the petroleum industry based on their 3-year average value of assets. Data of environmental pollutant emissions were obtained from the companies’ sustainability reports. Environmental indices were used to conduct the eco-efficiency analysis using the data envelopment analysis (DEA) to obtain the overall eco-efficiency of the company. Economic data were obtained from the 2008 GLOBAL 500. Another DEA was performed to obtain the overall technical efficiency. Eco-efficiency scores and economic scores were analyzed using the Pearson’s coefficient of correlation and the Spearman rank correlation coefficient Performance is gauged through the eco-efficiency indicator which is interpreted by environmentalists, economists and scientist to assess the reduction of adverse impacts on the environment. Results show a weak positive relationship between eco-efficiency and technical efficiency. The eco-efficiency indicator is a useful management tool in that it provides a means for managers and consumers alike to conduct environmental housekeeping.     

Identification of the change point: an overview

When a control chart addresses an out-of-control condition, a root-cause analysis should be started to identify and eliminate the special cause(s) of variation manifested in the process. The change point refers to the time when a special cause(s) takes place in the process and leads it to a departure from the in-control condition to an out-of-control condition. Identification of the change point is considered as an essential step for a root-cause analysis in both univariate and multivariate processes. If a change manifests in a normally distributed process mean, variance, or both, then the change point should be identified in the process mean, variance, or both, respectively. This paper attempts to comprehensively review the researches that considered the mean change point in different environment corresponding to univariate and multivariate normal processes.     

Microstructure evolution of gold thin films under spherical indentation for micro switch contact applications

RF MEMS (Radio Frequency Micro Electro Mechanical System) switches are promising devices but their gold-on-gold contacts, assimilated for this study to a sphere/plane contact, represent a major reliability issue. A first step toward understanding failure mechanisms is to investigate the contact metal microstructure evolution under static and cyclic loading. After static and cyclic loading of sputtered gold thin films under spherical indentation, high-resolution Electron Back Scatter Diffraction (EBSD) is used to investigate the contact area. Grain rotation against {111} fiber texture of 1-μm-thick sputtered gold thin film is a signature of plastic deformation. Grain rotation is observed above 1.6 mN under static loading using a spherical diamond indenter with 50-μm tip radius. The heterogeneity in grain rotation observed corresponds to a greater plastic deformation in the middle of the indent than at the edge. A 30° grain rotation due to cyclic work hardening is observed for a half-million mechanical cycles under 300 μN load using a spherical gold tip (20 μm radius). The same test in hot switching mode induces a grain growth in the contact area. Therefore, thermal effects occurring during hot switching are underlined.