H2S Reactive Absorption from Off‐Gas in a Spray Column: Insights from Experiments and Modeling

H₂S removal from an off‐gas stream was performed in a spray column by H₂S reactive absorption into a NaOH solution. The individual and interactive effects of three independent operating variables on the percentage of absorbed H₂S were investigated: the initial pH of the scrubbing solution, the initial scrubbing solution temperature, and the volumetric liquid‐to‐gas ratio. The optimum operating variables were determined by response surface methodology (RSM) attaining a percentage of absorbed H₂S of 98.7 ± 0.2 %. Additionally, the process performance was modeled by an artificial neural network (ANN) to predict the percentage of absorbed H₂S. The results showed that the experimental data agreed better with the ANN model than with the RSM results.     

Controlled Preparation and Characterization of Nigella Sativa Electrospun Pad for Controlled Release

Silicon - Nigella sativa (NS) oil is an anti-inflammatory agent in the traditional medicine. In the present study, novel electrospun mats contained NS oil/polyacrylonitrile as a sustained release...     

A novel bilayer drug-loaded wound dressing of PVDF and PHB/Chitosan nanofibers applicable for post-surgical ulcers

A novel bilayer nanofibrous wound dressing, with enhanced mechanical properties is successfully fabricated. This membrane, consisted of polyvinylidenefluoride (PVDF) nanofibers for providing tensile strength and polyhydroxybutyrate/chitosan (PHB/CTS) nanofibers loaded with gentamicin with ability of controlled drug delivery, is a great choice for post-surgical ulcers. Mechanical properties showed dramatically improvement of tensile strength by addition of PVDF layer. Gentamycin release represented both an immediate and a sustained release of about 24?h and 1 week, respectively and release increment with increase of CTS ratio. Results also revealed that drug release in structures follow first order kinetic and Fickian release mechanism.     

Preparation and Characterization of Nanosized Pomegranate Peel-Based Activated Carbon for Application in Pyridine Removal from Aqueous Solution

Theoretical Foundations of Chemical Engineering - Effect of activating procedure on the physic-chemical properties and adsorption performance of activated carbon was investigated. For this,...     

Characterization of the Ion Beam Current Density of the RF Ion Source with Flat and Convex Extraction Systems

Silicon - The characterization of ion beam current density distribution and beam uniformity is crucial for improving broad-beam ion source technologies. The design of the broad ion beam extraction...     

Rapid synthesis of new block copolyurethanes derived from L‐leucine‐PEG in ionic liquids under microwave irradiation

This study concerns the synthesis of novel multi block polyurethane (PU) copolymers containing eco‐friendly segments, taking the advantage of ionic liquids (IL)s under microwave irradiation. For this, L ‐leucine anhydride cyclodipeptide (LAC) was prepared and then a new class of poly(ether‐urethane‐urea)s (PEUUs) was synthesized with two types of ILs, including room temperature imidazolium (RTIL)s and molten ammonium type ILs. ILs were used as reaction media and PUs were prepared via two‐step polymerization method. Polymerization reaction was also conducted under conventional heating method in N‐methyl pyrrolidone (NMP) as reaction solvent. In the first step, 4,4′‐methylene‐bis(4‐phenylisocyanate) (MDI) was reacted with LAC to produce isocyanate‐terminated poly(imide‐urea) oligomers as hard segment. Chain extension of the resulting prepolymer with polyethyleneglycol (PEG) of molecular weights of 400 (PEG‐400) was the second step to furnish a series of new PEUUs. These multiblock copolymers are optically active, thermally stable and soluble in amide‐type solvents. PEUUs prepared in ILs under microwave irradiation showed more phase separation and crystallinity than PEUU prepared under conventional method. Some structural characterization and physical properties of these PEUUs, prepared under different methods, are reported and compared. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Refractive index determination in fuel cells using high-resolution laser heterodyne interferometer

In this paper, we present an interferometry method for refractive index determination in membranes of fuel cells. This technique is based on the use of an improved laser heterodyne interferometer. The photocurrents of the avalanche photodiodes, resulting from reflected beams of the optical head, are led to the signal conditioner and digital signal processing sections. The optical path difference between the target and reference paths is fixed, and as a result, the phase shift is calculated in terms of the refractive index shift. In addition, nonlinearity of this system is analyzed and modeled with different neural networks and adaptive filter algorithms. For neural networks, the radial basis function (RBF), the multi-layer perceptron (MLP), and the stacked generalization method are simulated. In adaptive filter algorithms, the least mean square (LMS), the normalized least mean square (NLMS), the recursive least squares (RLS), and the affine projection algorithm (APA) are applied. The simulation results indicate that the RLS method is faster and contains minimum mean square error (MSE) compared to the other approaches. Also, comparison between two main approaches shows that the nonlinearity of refractive index determination can be effectively modeled with adaptive filter algorithms.