Anomalous behavior during explosions of CH4 in oxygen-enriched air

Explosion tests were performed for CH₄/O₂/N₂ mixtures in a non-adiabatic 5 L cylindrical vessel. Experiments were run for mixtures with stoichiometric CH₄/O₂ ratio, changing the oxygen air enrichment factor, E = O₂/(O₂ + N₂), from 0.21 (air) to 1 (pure oxygen). Oscillating pressure time histories with over-adiabatic peaks (up to 240 bar) have been measured. The oscillating behaviors can be attributed to the occurrence of cycles of condensation and vaporization of the water produced during combustion. Such cycles culminate in the rapid phase transition of the condensed water, leading to the over-adiabatic pressure peaks.     

Evaluation of Different Conditions of Contact for Caprolactam Migration from Multilayer Polyamide Films into Food Simulants

Caprolactam, the polyamide 6 (PA‐6) monomer, can migrate during food processing. At cooking temperatures, migration is accelerated and plastic components could degrade, giving off low molecular mass compounds, which can migrate into food. In this work, caprolactam migration from multilayer films containing PA‐6 for meat foodstuffs and cheese packaging was performed at contact conditions of 40°C/10 days and 100°C/30 min. The migration into water ranged from 0.89 to 1.22 mg/dm² and 0.92 to 1.21 mg/dm², into 3% acetic acid from 1.29 to 1.74 mg/dm² and 1.13 to 1.62 mg/dm² and into olive oil from 1.18 to 1.98 mg/dm² and 0.50 to 0.80 mg/dm² for films intended for meat foodstuffs for 10 days at 40°C and 30 min at 100°C, respectively. Among PA‐6 films used for cheese, caprolactam migration into water ranged from 0.17 to 0.91 mg/dm² and 0.74 to 1.04 mg/dm², into 3% acetic acid from 1.15 to 1.26 mg/dm² and 1.11 to 1.37 mg/dm² and into olive oil from 0.23 to 0.83 mg/dm² and 0.37 to 0.56 mg/dm² for 10 days at 40°C and 30 min at 100°C, respectively. Caprolactam migration evaluation into water and 3% acetic acid at 100°C/30 min could replace the need to apply the test at 40°C/10 days, since similar results were obtained under both conditions. In the case of PA‐6 for meat foodstuffs, caprolactam migration into olive oil was highly affected by different conditions of contact, showing values two to three times higher at 40°C/10 days than at 100°C/30 min. For cheese films, caprolactam migration into olive oil was higher at 40°C for 10 days. Copyright © 2013 John Wiley & Sons, Ltd.     

Heavy metals uptake by sonicated activated sludge: relation with floc surface properties

The effects of sonication of activated sludge on heavy metal uptake were in a first time investigated in respect with potential modifications of floc surface properties. The treatment led to the simultaneous increase of specific surface area and of the availability of negative and/or hydrophilic sites. In parallel, organic matter was released in the soluble fraction. Sorption isotherms of cadmium and copper showed that uptake characteristics and mechanisms were highly dependent on both heavy metal species and specific energy supplied. The increase of both specific surface area and fixation sites availability led to the increase of Cd(II) uptake. For Cu(II), organic matter released in soluble phase during the treatment seemed to act as a ligand and to limit adsorption on flocs surface. Three different heavy metals uptake mechanisms have been identified: proton exchange, ion exchange and (co)precipitation.     

Potential method to improve the treatment efficiency of persistent contaminants in industrial wastewater

The objective of this work was to evaluate a potential method for improving the treatment efficiency of persistent contaminants in industrial wastewater. Adsorption with powdered activated carbon (PAC) was applied as pre-treatment and operational conditions as pH, temperature, carbon concentration and time were investigated in laboratory scale for different streams generated in a fine chemical industry. Chemical oxygen demand (COD) removal efficiencies of 63 and 50% were attained for two important industrial streams, Product C after acid treatment and precipitation and Influent, at pH 7, room temperature and with 5 and 15 g l(-1) of PAC, respectively. Biodegradation assays showed that PAC adsorption enhanced COD removal efficiency. PAC pre-treatment increased the COD removal of Product C after production stream from 15 to 80% and improved the biodegradability of the Influent stream by 50%.     

A novel porous scaffold fabrication technique for epithelial and endothelial tissue engineering

Porous scaffolds have the ability to minimize transport barriers for both two- (2D) and three-dimensional tissue engineering. However, current porous scaffolds may be non-ideal for 2D tissues such as epithelium due to inherent fabrication-based characteristics. While 2D tissues require porosity to support molecular transport, pores must be small enough to prevent cell migration into the scaffold in order to avoid non-epithelial tissue architecture and compromised function. Though electrospun meshes are the most popular porous scaffolds used today, their heterogeneous pore size and intense topography may be poorly-suited for epithelium. Porous scaffolds produced using other methods have similar unavoidable limitations, frequently involving insufficient pore resolution and control, which make them incompatible with 2D tissues. In addition, many of these techniques require an entirely new round of process development in order to change material or pore size. Herein we describe “pore casting,” a fabrication method that produces flat scaffolds with deterministic pore shape, size, and location that can be easily altered to accommodate new materials or pore dimensions. As proof-of-concept, pore-cast poly(ε-caprolactone) (PCL) scaffolds were fabricated and compared to electrospun PCL in vitro using canine kidney epithelium, human colon epithelium, and human umbilical vein endothelium. All cell types demonstrated improved morphology and function on pore-cast scaffolds, likely due to reduced topography and universally small pore size. These results suggest that pore casting is an attractive option for creating 2D tissue engineering scaffolds, especially when the application may benefit from well-controlled pore size or architecture.     

A Microfluidic Ion Pump for In Vivo Drug Delivery

Implantable devices offer an alternative to systemic delivery of drugs for the treatment of neurological disorders. A microfluidic ion pump (µFIP), capable of delivering a drug without the solvent through electrophoresis, is developed. The device is characterized in vitro by delivering γ‐amino butyric acid to a target solution, and demonstrates low‐voltage operation, high drug‐delivery capacity, and high ON/OFF ratio. It is also demonstrated that the device is suitable for cortical delivery in vivo by manipulating the local ion concentration in an animal model and altering neural behavior. These results show that µFIPs represent a significant step forward toward the development of implantable drug‐delivery systems.     

Deactivation and regeneration of spent three-way automotive exhaust gas catalysts (TWC)

Topics in Catalysis - The effect of oxidation, oxy-chlorination and reduction treatments at elevated temperatures on the dispersion of palladium (Pd) and rhodium (Rh) for commercially aged...     

Requirements engineering within a large-scale security-oriented research project: lessons learned

Requirements engineering has been recognized as a fundamental phase of the software engineering process. Nevertheless, the elicitation and analysis of requirements are often left aside in favor of architecture-driven software development. This tendency, however, can lead to issues that may affect the success of a project. This paper presents our experience gained in the elicitation and analysis of requirements in a large-scale security-oriented European research project, which was originally conceived as an architecture-driven project. In particular, we illustrate the challenges that can be faced in large-scale research projects and consider the applicability of existing best practices and off-the-shelf methodologies with respect to the needs of such projects. We then discuss how those practices and methods can be integrated into the requirements engineering process and possibly improved to address the identified challenges. Finally, we summarize the lessons learned from our experience and the benefits that a proper requirements analysis can bring to a project.