Electrospun polyurethane membrane with Ag/ZnO microparticles as an antibacterial surface on polyurethane sheets

A method of antibacterial modification of the polyurethane (PU) surface is presented in this article. An electrospun PU membrane with an incorporated antibacterial agent was applied as a coating of the PU sheets. As an antibacterial agent, a hybrid bimetallic filler was used; it combined the antibacterial effects of silver and zinc oxide. With an electrospun submicrometer‐fiber membrane, the filler was uniformly and thinly applied on the PU surface by compression molding. The antibacterial activities of three filler concentrations were tested, and they demonstrated an effective antibacterial action against Staphylococcus aureus and Escherichia coli. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 43020.     

Distributed and collaborative visualization of large data sets using high-speed networks

We describe an architecture for distributed collaborative visualization that integrates video conferencing, distributed data management and grid technologies as well as tangible interaction devices for visualization. High-speed, low-latency optical networks support high-quality collaborative interaction and remote visualization of large data.     

High-definition multimedia for multiparty low-latency interactive communication

We describe a high-quality collaborative environment that uses High-Definition (HD) video to achieve near realistic perception of a remote site. The capture part, consisting of a HD camera, Centaurus HD-SDI capture card, and UltraGrid software, produces a 1.5 Gbps UDP data stream of uncompressed HD video that is transferred over a 10GE network interface to the high-speed IP network. The HD video stream displaying uses either a software-based solution with color depth down-sampling and field de-interlacing, or another Centaurus card. Data distribution to individual participants of the videoconference is achieved using a user-controlled UDP packet reflector based on the Active Element idea. The viability of this system has been demonstrated at the iGrid 2005 conference for a three-way high quality videoconference among sites in the Czech Republic, Louisiana, and California.     

Evolution of volatile aldehydes in Iberian ham matured under different processing conditions

To evaluate the influence of the Iberian ham processing conditions in the evolution of volatile aldehydes, 35 hams were processed in two plants following different conditions of relative humidity and temperature. For this, free fatty acids, peroxide values and volatile aldehydes were quantified in the hams. The highest increases in free fatty acids were noted during the drying stage in both processing plants. The drying period also revealed the greatest increase in peroxide values, where the highest values were in those hams processed at higher temperatures. The temperature during post-salting and drying had a marked influence on the formation of volatile aldehydes, being responsible for the differences in volatile compounds of matured hams.     

The dynamic method of determination of the piezoelectric hydrostatic coefficients

The dynamic method of the determination of the piezoelectric hydrostatic coefficients, d_h, was improved. We have constructed new equipment for more exact measurement by means of the direct dynamic method. The piston for the high-pressure mechanical excitation of pressure changes was used. The advantage of the proposed method is a low frequency (about 1 Hz) pressure excitation. The lever hydraulic press is able to create the hydrostatic pressure inside the pressure chamber up to 70 MPa. The temperature control is realised by the PID temperature controller with a resistivity heater and by the compressor cooler.     

Building Orientation and Wind Effects Estimation

The methodology for estimating wind effects presented in this paper is based on the database-assisted design approach. It accounts for the effects of wind directionality, for the effects of the uncertainties in the parameters that determine wind effects, and for the effects of building orientation. The methodology yields estimates of wind effects that are far more realistic than those based on the conventional building code approach, which disregards uncertainties in those parameters, as well as the effects of wind directionality and building orientation, or accounts for these effects through the use of a blanket reduction factor. The pilot software on which the calculations presented in this paper are based is a first step toward modern computer-intensive electronic standards wherein wind loads can be calculated by using database-assisted reliability-based calculations of wind effects. We believe such standards will go a long way toward achieving significantly safer and more economical buildings in regions affected by strong winds.     

High-resolution characterization of hexagonal boron nitride coatings exposed to aqueous and air oxidative environments

Hexagonal boron nitride (h-BN) is believed to offer better passivation to metallic surfaces than graphene owing to its insulating nature,which facilitates blocking the flow of electrons,thereby preventing the occurrence of galvanic reactions.Nevertheless,this may not be the case when an h-BN-protected material is exposed to aqueous environments.In this work,we analyzed the stability of mono and multilayer h-BN stacks exposed to H2O2 and atmospheric conditions.Our experiments revealed that monolayer h-BN is as inefficient as graphene as a protective coating when exposed to H2O2.Multilayer h-BN offered a good degree of protection.Monolayer h-BN was found to be ineffective in an air atmosphere as well.Even a 10-15 layers-thick h-BN stack could not completely protect the surface of the metal under consideration.By combining Auger electron spectroscopy and secondary ion mass spectrometry techniques,we observed that oxygen could diffuse through the grain boundaries of the h-BN stack to reach the metallic substrate.Fortunately,because of the diffusive nature of the process,the oxidized area did not increase with time once a saturated state was reached.This makes multilayer (not monolayer) h-BN a suitable long-term oxidation barrier.Oxygen infiltration could not be observed by X-ray photoelectron spectroscopy.This technique cannot assess the chemical composition of the deeper layers of a material.Hence,the previous reports,which relied on XPS to analyze the passivating properties of h-BN and graphene,may have ignored some important subsurface phenomena.The results obtained in this study provide new insights into the passivating properties of mono and multilayer h-BN in aqueous media and the degradation kinetics of h-BN-coated metals exposed to an air environment.     

Ultrathin Hierarchical Porous Carbon Nanosheets for High‐Performance Supercapacitors and Redox Electrolyte Energy Storage

The design of advanced high‐energy‐density supercapacitors requires the design of unique materials that combine hierarchical nanoporous structures with high surface area to facilitate ion transport and excellent electrolyte permeability. Here, shape‐controlled 2D nanoporous carbon sheets (NPSs) with graphitic wall structure through the pyrolysis of metal–organic frameworks (MOFs) are developed. As a proof‐of‐concept application, the obtained NPSs are used as the electrode material for a supercapacitor. The carbon‐sheet‐based symmetric cell shows an ultrahigh Brunauer–Emmett–Teller (BET)‐area‐normalized capacitance of 21.4 µF cm^?2 (233 F g^?1), exceeding other carbon‐based supercapacitors. The addition of potassium iodide as redox‐active species in a sulfuric acid (supporting electrolyte) leads to the ground‐breaking enhancement in the energy density up to 90 Wh kg^?1, which is higher than commercial aqueous rechargeable batteries, maintaining its superior power density. Thus, the new material provides a double profits strategy such as battery‐level energy and capacitor‐level power density.     

Nanoparticle Interactions Guided by Shape‐Dependent Hydrophobic Forces

Self‐assembly of solvated nanoparticles (NPs) is governed by numerous competing interactions. However, relatively little is known about the time‐dependent mechanisms through which these interactions enable and guide the nanoparticle self‐assembly process. Here, using in situ transmission electron microscopy imaging combined with atomistic modeling, it is shown that the forces governing the self‐assembly of hydrophobic nanoparticles change with the nanoparticle shapes. By comparing how gold nanospheres, nanocubes, nanorods, and nanobipyramids assemble, it is shown that the strength of the hydrophobic interactions depends on the overlap of the hydrophobic regions of the interacting nanoparticle surfaces determined by the nanoparticle shapes. Specifically, this study reveals that, in contrast to spherical nanoparticles, where van der Waals forces play an important role, hydrophobic interactions can be more relevant for nanocubes with flat side faces, where an oriented attachment between the nanocubes is promoted by these interactions. The attachment of nanocubes is observed to proceed in two distinct pathways: nanocubes either: (i) prealign their faces before the attachment, or (ii) first connect through a misaligned (edge‐to‐edge) attachment, followed by a postattachment alignment of their faces. These results have important implications for understanding the interaction dynamics of NPs and provide the framework for the design of future self‐assembled nanomaterials.     

Influence of the constraint effect on the fatigue crack growth rate in S355 J2 steel using digital image correlation

Displacement fields around the fatigue crack tip for a constant value of stress intensity factor (SIF) range were measured using digital image correlation (DIC) technique on the S355 J2 steel grade. The data obtained were resolved into the T‐stress evaluation and quantification of its influence on the fatigue crack growth rate. The higher order terms of the Williams expansion (WE) were calculated as well. The displacements of a set of points outside of the plastic zone were selected for application of the over‐deterministic method (ODM) to obtain several initial WE terms. The computed values of T‐stress show good agreement with finite element analysis and literature. It was shown by collected experimental displacement, that the level of constraint influences the fatigue crack propagation rate.