Mn2O3/TiO2 nanofibers with broad-spectrum antibiotics effect and photocatalytic activity for preliminary stage of water desalination

Composite nanofibers consisting of Mn₂O₃ and TiO₂ were prepared by the electrospinning process, and tested as Gram-class-independent antibacterial agent and photocatalyst for organic pollutants degradation. Initially, electrospinning of a sol–gel consisting of titanium isopropoxide, manganese acetate tetrahydrate and poly(vinyl pyrrolidone) was used to produce hybrid polymeric nanofibers. Calcination of the obtained nanofibers in air at 650 °C led to produce good morphology Mn₂O₃/TiO₂ nanofibers. Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) were employed to characterize the as-spun nanofibers and the calcined product. X-ray powder diffractometry (XRD) analysis was also used to characterize the chemical composition and the crystallographic structure of the sintered nanofibers. The antibacterial activity of Mn₂O₃/TiO₂ nanofibers against Gram negative and Gram positive bacteria was investigated by calculating the minimum inhibitory concentration after treatment with the nanofibers. Investigations revealed that the lowest concentration of Mn₂O₃/TiO₂ nanofibers solution inhibiting the growth of Staphylococcus aureus ATCC 29231 and Escherichia coli ATCC 52922 strains is 0.4 and 0.8 μg/ml, respectively. Incorporation of Mn₂O₃ significantly improved the photodegradation of methylene blue (MB) dye under the visible light irradiation due to enhancing rutile phase formation in the TiO₂ nanofibers matrix.     

Survey of Short- and Medium-Span Bridge Damage Induced by Hurricane Katrina

This paper reports on a survey effort of damaged bridges conducted by the writers in the aftermath of Hurricane Katrina of August 2005. As with Hurricane Ivan in 2004, low-lying coastal bridges suffered severe damage due to hydrodynamic forces caused by storm surge. Consequently, transportation networks in the affected areas were disrupted. Since coastal bridges are considered lifelines for the communities they serve, their loss resulted in hindering rescue and recovery efforts. The purpose of this paper is to present related data as observed by the writers. Data collection and documentation of perishable data after natural disasters and before recovery and reconstruction efforts is of great importance. In the case of coastal bridges, they can help in improving future designs and rehabilitating existing ones. The majority of the surveyed bridges collapsed due to unseating. Hydrodynamic forces due to wave impact and water current on the superstructure proved to exceed the capacity of common connections between the superstructure and the substructure for short- and medium-span bridges.     

Synthesis of Smart Core-shell Nanocomposites with Enhanced Photocatalytic Efficacy

ABSTRACT

This current research represents practical synthetic protocol for novel core-shell nanocomposites (CSNCs) containing titania. TiO₂/poly(anthranilic acid, m-aminobenzoic acid, and o-phenylenediamine) (TiO₂/PANA-m-ABA-o-PDA) CSNCs were fabricated applying 2:2:1 molar ratio of the appropriate monomers and varied loads of TiO₂ via polycondensation. The fabrication of the TiO₂/PANA-m-ABA- o-PDA CSNCs was affirmed using various characterizations. The bond between TiO₂ and PANA-m-ABA-o-PDA was detected in the FTIR spectra. The CSNC’s features are having core-shell structures with sizes 12–27 nm. Under irradiation, the CSNCs exhibit intensive photocatalysis efficacy toward methylene blue degradation. Acceptable explanations of the photocatalytic efficiency consequences were substantiated. The zeta potential of a particle (ζ), the polydispersity index (PDI), and y-intercept were anticipated via dynamic light scattering (DLS) of the terpolymer colloidal system. The procedure manipulates a facile, new, beneficial as well as cheap synthetic technique to fabricate innovative CSNC as a new potential formulation.     

Melt rheology of nanocomposites based on acrylic copolymer and cellulose whiskers

Nanocomposites based on poly(styrene-co-hexylacrylate) copolymer and cellulose whiskers as the nanosize filler were prepared by in situ miniemulsion polymerization and their melt rheological behaviours were investigated under dynamic shear conditions. The effects of γ-methacryloxypropyl triethoxysilane (MPS) content along with the whisker loading were explored. In the absence of whiskers, a transition from a liquid- to a solid-like behaviour was observed when the polymer was synthesized in the presence of MPS. When cellulose nanofiller was added, the storage modulus G′ and the dynamic viscosities η of the nanocomposites increased monotonically with whisker content and the resulting materials displayed a solid-like behaviour. Above 2 wt.%. loading, a percolated interconnected whisker-whisker network is built up, producing a jump in the storage modulus and strong shear-thinning behaviour of the viscosity. However, as the nanocomposites were prepared in the presence of 3% of MPS, no enhancement nor in the storage modulus nor in the viscosity was observed up to 5 wt.%. of whisker loading. Such a phenomenon was ascribed to inhibition of build-up of the whisker network. The non-linear viscoelastic behaviour of the nanocomposites was also investigated and analysed in terms of the breakdown of different networks, namely the filler-filler and the polymer-filler networks.     

Development and model-based transparency analysis of an Internet-distributed hardware-in-the-loop simulation platform

This paper summarizes efforts to integrate, for the first time, two geographically dispersed hardware-in-the-loop simulation setups over the Internet in an observer-free way for an automotive application. The two setups are the engine-in-the-loop simulation setup at the University of Michigan (UM) in Ann Arbor, MI, USA, and the driver-in-the-loop ride motion simulator at the US Army Tank-Automotive Research, Development and Engineering Center (TARDEC) in Warren, MI, USA. The goal of such integration is to increase the fidelity of experiments and to enable concurrent geographically dispersed systems engineering. First, experiments with the actual hardware are presented. The concept of transparency is discussed, and the infeasibility of performing a baseline experiment with ideally integrated hardware is presented as a challenge to characterize the transparency of the experimental setup. This motivates the second half of the paper, in which a model-based approach is taken to analyze the transparency of the system. The conclusion is that an observer-free solution is feasible for integrating the two pieces of hardware over the Internet in a transparent manner, even if the nominal delay is increased by four times. It is also found that different signals in the system can exhibit different levels of transparency.     

Evolution of the Nile River drought risk based on the streamflow record at Aswan station,Egypt

The drought in Ethiopian Highlands, source of the Nile flood, has been in the news off and on since the early 1970s, to such an extent that it can be inquired if the Nile basin users are exposed to a drought risk increasing in time. Based on a methodology developed by the author and previously used for flood risk assessment, this article aims to study the progressive modification of the likelihood of occurrence of a certain drought event in the Nile River, based on the annual record available at the Aswan station, Egypt. The record is thoroughly studied to detect possible trends and seasonalities. It is then divided into subsamples, on which frequency analyses were performed using the linear moments (L-moments) method. L-moments perform well with short records and are less sensitive to extremes. The 10-, 25-, 50- and 100-year droughts are estimated based on every subsample, then the temporal evolutions of these estimates are investigated. The results show a cyclic pattern of the drought risk, confirming the previously suggested non-stationarity of the flow series as one of the possible interpretation of the Hurst phenomenon.     

Investigation of some copolymers based on acrylic salts as circulation loss control agents

In this work, six copolymers were prepared from sodium and potassium acrylate. Both salts individually were copolymerized with acrylamide, methacrylic acid and acrylic acid at different ratios. The monomer reactivity ratios for copolymerization reactions of both of acrylate salts with acrylamide, methacrylic acid and acrylic acid, in solution with azobisisobutyronitrile (AIBN) as an initiator, were estimated by atomic adsorption analyser. The chemical structure was confirmed by atomic adsorption spectroscopy and FT-IR spectroscopy.The prepared copolymers were investigated as loss circulation control materials by measuring different filtration parameters such as; spurt loss, fluid loss and permeability plugging tester value according to the American Petroleum Institute (API) standard. From the obtained data, it was found that the 0.6% from the poly[PA-co-AM]_(0.4:0.6) exhibited the best results of the filtration parameters among the other copolymers. At the same time all the studied copolymers enhanced the rheological properties of the drilling mud. These results were discussed on the light of the swelling capacity of the copolymers.     

Influence of Nonionic Rosin Surfactants on Surface Activity of Silica Particles and Stability of Oil in Water Emulsions

Rosin as a natural product has become a source for production of less toxic bio-surfactants to produce emulsions which are widely used in various agriculture and food products, cosmetic, and pharmaceutical industries. In this respect, a nonionic surfactant was prepared from reaction of rosin acids and rosin maleic anhydride adduct with poly(ethylene glycol) monomethyl ether 750 (MPEG 750) to produce a rosin ester (RMPEG 750). The surface activity parameters of the prepared surfactants, such as surface excess concentration (Γ _max), the area per molecule at interface (A _min), and the effectiveness of surface tension reduction, were measured to determine the micellization and adsorption characteristics of the prepared surfactants at the water/air interface. The adsorption of the prepared surfactants on the surface of either hydrophilic or hydrophobic silica particles was determined using a spectrophotometric method. Interfacial tension between water and toluene were measured to select the best condition to obtain toluene/water emulsion in the presence of modified solid silica particles. The effects of silica particle hydrophilicity and the surfactant concentrations on the surface, interfacial activity, and on the emulsion drop size were also investigated.     

Effect of the solvent on growth of titania nanotubes prepared by anodization of Ti in HCl

The effect of the solvent on the anodic growth of titania nanotubes in HCl dissolved in water, ethylene glycol and 2-propanol was studied. These nanotubes grow with locally rapid breakdown of the passive TiO₂ film forming a forest of nanotubes-bearing microtowers with the background of passive TiO₂ Film. These bundles of assembled-groups of titania nanotubes look like Pillars corals. The low relative permittivity of the 2-propanol led to lowering of dissociation of HCl and hence lowering the activity of H⁺ and Cl⁻ ions which in turn led to suppress of dissolution of titania and increasing the growth rate of the titania nanotubes. The X-ray diffraction pattern showed that the titania nanotubes after annealing change to the crystalline anatase phase. The anodic films showed characteristic coloration with intensity and color that changes (qualitatively) with time of anodization.