Challenges of future multimedia QoE monitoring for internet service providers

Multimedia Tools and Applications - The ever-increasing network traffic and user expectations at reduced cost make the delivery of high Quality of Experience (QoE) for multimedia services more...     

Dual-axis thermal convective inclinometer based on CNT/PDMS composite

This paper presents the design, fabrication, and characterization of a novel inclination-angle sensor (inclinometer) using heating and sensing elements based on conductive polydimethylsiloxane (PDMS) composited with carbon nanotubes (CNTs). The inclinometer consists of a PDMS cube-shaped chamber, a CNTs/PDMS composite-based heater, and four CNTs/PDMS composite-based temperature sensors. The working mechanism of this sensor is based on thermal convective sensing theory on the basis of the detection of thermal disturbance caused by inclination-induced convection in a sealed chamber. In order to prepare the conductive CNTs/PDMS composite, toluene was applied as a solvent to facilitate CNT dispersion in PDMS matrix and then was removed by evaporation. The resistive heating and thermal sensing properties of CNT/PDMS composite-based elements were tested and analyzed first. Then, the responses to inclination-angle were monitored and reported. Experimental results demonstrate that the inclinometer can measure dual-axis angular position in the range of 360° with high stability and repeatability.     

Apparent contact angles of liquid water droplet breaking through a gas diffusion layer of polymer electrolyte membrane fuel cell

The lattice Boltzmann method is used to simulate the three-dimensional dynamic process of liquid water breaking through the gas diffusion layer (GDL) in the polymer electrolyte membrane fuel cell. An accurate method is introduced to analyze asymmetric droplet shape. Ten micro-structures of Toray GDL were built based on a stochastic geometry model. It was found that asymmetric droplets are produced on the GDL surfaces. Their local apparent contact angles vary with different view angles and geometries. They are different to the idealized contact angles by symmetric simplification. It was concluded that the apparent contact angles are influenced by GDL structures and view angles. This information can help to bridge the gap between mesoscale and cell-scale simulations in the field of fuel cell simulation.     

Layered PtSe2 for Sensing,Photonic, and (Opto‐)Electronic Applications

Since the first experimental discovery of graphene 16 years ago, many other 2D layered nanomaterials have been reported. However, the majority of 2D nanostructures suffer from relatively complicated fabrication processes that have bottlenecked their development and their uptake by industry for practical applications. Here, the recent progress in sensing, photonic, and (opto‐)electronic applications of PtSe₂, a 2D layered material that is likely to be used in industries benefiting from its high air‐stability and semiconductor‐technology‐compatible fabrication methods, is reviewed. The advantages and disadvantages of a range of synthesis methods for PtSe₂ are initially compared, followed by a discussion of its outstanding properties, and industrial and commercial advantages. Research focused on the broadband nonlinear photonic properties of PtSe₂, as well as reports of its use as a saturable absorber in ultrafast lasers, are then reviewed. Additionally, the advances that have been achieved in a range of PtSe₂‐based field‐effect transistors, photodetectors, and sensors are summarized. Finally, a conclusion on these results along with the outlook for the future is presented.     

Rubber composites based on graphene nanoplatelets,expanded graphite,carbon nanotubes and their combination: A comparative study

Solution styrene butadiene rubber (S-SBR) composites reinforced with graphene nanoplatelets (GnPs), expanded graphite (EG), and multiwalled carbon nanotubes (MWCNTs) were prepared and the electrical and various mechanical properties were compared to understand the specific dispersion and reinforcement behaviours of these nanostructured fillers. The electrical resistivity of the rubber composite gradually decreased with the increase of filler amount in the composite. The electrical percolation behaviour was found to be started at 15 phr (parts per hundred rubber) for GnP and 20 phr for EG filled systems, whereas a sharp drop was found at 5 phr for MWCNT based composites. At a particular filler loading, dynamic mechanical analysis and tensile test showed a significant improvement of the mechanical properties of the composites comprised of MWCNT followed by GnP and then EG. The high aspect ratio of MWCNT enabled to form a network at low filler loading and, consequently, a good reinforcement effect was observed. To investigate the effect of hybrid fillers, MWCNT (up to 5 phr) were added in a selected composition of EG based compounds. The formation of a mixed filler network showed a synergistic effect on the improvement of electrical as well as various mechanical properties.     

In Vivo Examination of an Injectable Hydrogel System Crosslinked by Peptide–Oligosaccharide Interaction in Immunocompetent Nude Mice

Hydrogels can serve as matrices to mimic natural tissue function and be used for wide‐ranging applications such as tissue regeneration and drug delivery. Injectable hydrogels are particularly favorable because their uses are minimally invasive. However, creating moldable substance for injection often results in compromised function and stability. This study reports an injectable hydrogel system crosslinked by peptide–oligosaccharide noncovalent interaction. The dynamic network shows fast self‐healing, a property essential for injectability. Injected hydrogels in immunocompetent mice and release of encapsulated compound are monitored up to 9 months by magnetic resonance imaging (MRI) and optical imaging. This surprisingly stable hydrogel does not cause adverse inflammatory response, as analyzed by measuring cytokine levels, immunohistochemistry, and MRI. Hydrogel degradation is associated with invasion of macrophages and vascular formation. The facile synthesis, high biocompatibility, and stability of this injectable hydrogel can lead to various experimental and clinical applications in regenerative medicine and drug delivery.     

Methane emissions from a small wind shielded lake determined by eddy covariance, flux chambers, anchored funnels, and boundary model calculations: a comparison

Lakes are large sources of methane, held to be responsible for 18% of the radiative forcing, to the atmosphere. Periods of lake overturn (during fall/winter) are short and therefore difficult to capture with field campaigns but potentially one of the most important periods for methane emissions. We studied methane emissions using four different methods, including eddy covariance measurements, floating chambers, anchored funnels, and boundary model calculations. Whereas the first three methods agreed rather well, boundary model estimates were 5-30 times lower leading to a strong underestimation of methane fluxes from aquatic systems. These results show the importance of ebullition as the most important flux pathway and the need for continuous measurements with a large footprint covering also shallow parts of lakes. Although fluxes were high, on average 4 mmol m(-2) d(-1) during the overturn period, water column microbial methane oxidation removed 75% of the methane and only 25% of potential emissions were released to the atmosphere. Hence, this study illustrates second the importance of considering methane oxidation when estimating the flux of methane from lakes during overturn periods.     

Assessment of the sensory quality and shelf stability of selected Horro beef muscles in Ethiopia

The objective of this work was to assess sensory quality and retail life of Horro beef muscles in Ethiopia. Six muscles: M. rhomboideus (RM), M. infraspinatus (IS), M. longissimus lumborum (LL), M. semimembranosus (SM), M. biceps femoris (BF) and M. rectus femoris (RF) were considered. Sensory quality of the muscles was rated by a 9-member trained panel for palatability, tenderness, juiciness, amount of connective tissue (ACT), lean color and surface discoloration and measured by Warner-Bratzler Shear Force (WBSF). Retail life of the six muscles were evaluated for CIE 1976 L^∗a^∗b^∗ color values across 6 days. Significant differences (p < 0.05) between muscles for all sensory attributes and WBSF were found. Significant L^∗a^∗b^∗ color values of muscles and USDA quality grades by retail life were found (p < 0.05). Significant correlations (p < 0.05 or p < 0.01) of key parameters were also identified.     

On the mode of action of N-phenyl-2-naphthylamine in plants

N-phenyl-2-naphthylamine, a sediment contaminant previously identified as a major toxicant of site-specific importance was investigated for its mode of toxic action. From short-term bioassays with daphnids, fish eggs, bacteria, and algae it appears that this compound has specific phytotoxic properties at concentrations below 100 microg/L, which cannot be explained assuming an unspecific narcosis type of action in plants. Also, hydroxy-, nitro-, and methylderivatives show clear excess toxicity as compared to baseline toxic effects. Of several plant-specific growth and development processes investigated, only photosynthesis could be demonstrated to be affected at short exposure times and low concentrations. Disturbance of primary photosynthetic reactions such as oxygen evolution and fluorescence quenching, however, becomes only apparent after 2-3 h of exposure, which is in sharp contrast to known specific inhibitors targeting processes such as electron transport or ATP production. This, and concentration-time-effect modeling lead to the suggestion that N-phenyl-2-naphthylamine acts intracellular as a reactive compound in cell membranes producing irreversible, and thus cumulative, damage over time in algae. The effects may become first apparent in membrane-rich compartments such as the algal chloroplast.