Investigations on gradient a.c. conductivity characteristics of bamboo (Dendrocalamus strictus)

Effect of temperature and frequency variation on a.c. conductivity of bamboo was determined by using a 4274 A Multi-Frequencies LCR meter. Electrical measurements were carried out in the temperature range 24–120°C and in the frequency range 4–100 kHz. It was observed that the a.c. conductivity increased initially and then decreased with increase of temperature and frequencies. The increase of distance from outer surface to the inner surface side increased the a.c. conductivity values and showed the grading in a.c. conductivity behaviour. Two phases of a.c. conductivity behaviour with temperature exist in bamboo. At 10 mm distance a.c. conductivity suddenly increases which is the critical depth from skin for this bamboo. Increase of temperature, at all the frequencies increases the a.c. conductivity initially and then decreases. Downward peaks in a.c. conductivities are observed at all the frequencies due to the presence of moisture in bamboo, which liberated on heating. Sharp peak is observed in case of sample 4, which is inner most strip. Maximum sharp peak is observed at lowest 4 kHz frequency.     

Densities and Refractive Indices of Binary Mixtures of Benzene with Triethylamine and Tributylamine at Different Temperatures

Experimental densities, ρ, and refractive indices, n _D for binary liquid mixtures of benzene with triethylamine (TEA) and tributylamine (TBA) have been measured as a function of composition in the temperature range from 278.15 to 318.15 K. The excess molar volume, V ^E , and its temperature dependence, dV ^E /dT for the binary mixtures were calculated using the experimental data. The values of V ^E for the mixtures were also estimated by using the Flory statistical theory and refractive index.     

Parallel asynchronous particle swarm optimization

The high computational cost of complex engineering optimization problems has motivated the development of parallel optimization algorithms. A recent example is the parallel particle swarm optimization (PSO) algorithm, which is valuable due to its global search capabilities. Unfortunately, because existing parallel implementations are synchronous (PSPSO), they do not make efficient use of computational resources when a load imbalance exists. In this study, we introduce a parallel asynchronous PSO (PAPSO) algorithm to enhance computational efficiency. The performance of the PAPSO algorithm was compared to that of a PSPSO algorithm in homogeneous and heterogeneous computing environments for small- to medium-scale analytical test problems and a medium-scale biomechanical test problem. For all problems, the robustness and convergence rate of PAPSO were comparable to those of PSPSO. However, the parallel performance of PAPSO was significantly better than that of PSPSO for heterogeneous computing environments or heterogeneous computational tasks. For example, PAPSO was 3.5 times faster than was PSPSO for the biomechanical test problem executed on a heterogeneous cluster with 20 processors. Overall, PAPSO exhibits excellent parallel performance when a large number of processors (more than about 15) is utilized and either (1) heterogeneity exists in the computational task or environment, or (2) the computation-to-communication time ratio is relatively small.     

Evaluation of a.c. conductivity behaviour of graphite filled polysulphide modified epoxy composites

Composites of epoxy resin having different amounts of graphite particles have been prepared by solution casting method. Temperature dependence of dielectric constant, tan δ and a.c. conductivity was measured in the frequency range, 1–20 kHz, temperature range, 40–180°C for 0.99, 1.96 and 2.91 wt% graphite filled and unfilled epoxy composites. It was observed that the dielectric constant, tanδ and a.c. conductivity increase with increasing temperature. Near the transition temperature the materials show anomalous behaviour for the observed properties. Peaks of dielectric constant, tan δ and a.c. conductivity were observed to shift towards lower temperature with increasing frequency. Clear relaxation (tan δ) peaks around 169°C were observed in epoxy resin, which shifted to lower temperature side on increasing the frequency. Addition of 2.91 wt% graphite shifted the tan δ peaks towards higher temperature side by creating hindrances to the rotation of polymer dipoles. Addition of 2–91 wt% graphite leads to an increased relaxation time τ of dipoles in polysulphide epoxy from 1.44 × 10⁻⁵− 3.92 × 10⁻⁵ (s) at 90°C by creating the hindrance to the rotation of dipoles.     

Influence of steady shear flow on dynamic viscoelastic properties of un-reinforced and Kevlar,glass fibre reinforced LLDPE

An experimental study was conducted to observe the effects of parallel-superposed flow condition on viscoelastic properties of LLDPE, Kevlar fibre reinforced LLDPE and hybrid of short glass fibre and Kevlar fibre reinforced LLDPE. Parallel-plate rheometer was employed for these tests. Rheological parameters such as loss modulus (G″) and dynamic viscosity (η′) do not vary significantly on superposing steady state shear with oscillatory shear in the studied range of experiment at 185°C in un-reinforced LLDPE. Kevlar fibre reinforced LLDPE and Kevlar/glass fibre reinforced LLDPE showed significant changes in the flow behaviour under various sets of superposed conditions. Storage modulus (G′), andG″ become highly sensitive to low oscillatory angular frequencies (ω) under superposed conditions. These curves show two different regions with increased ω value. At low ω values, parametersG′ andG″ change sharply reaching a certain value, thereafter, changes are moderate with increased ω. In case of η′ a maxima is observed, position of which, depends upon the value of steady shear rate. Maxima shifts towards higher frequencies with the increased steady shear rate.     

Unveiling the hidden bride: deep annotation for mapping and migrating legacy data to the Semantic Web

The success of the Semantic Web crucially depends on the easy creation, integration, and use of semantic data. For this purpose, we consider an integration scenario that defies core assumptions of current metadata construction methods. We describe a framework of metadata creation where Web pages are generated from a database and the database owner is cooperatively participating in the Semantic Web. This leads us to the deep annotation of the database—directly by annotation of the logical database schema or indirectly by annotation of the Web presentation generated from the database contents. From this annotation, one may execute data mapping and/or migration steps, and thus prepare the data for use in the Semantic Web. We consider deep annotation as particularly valid because: (i) dynamic Web pages generated from databases outnumber static Web pages, (ii) deep annotation may be a very intuitive way to create semantic data from a database, and (iii) data from databases should remain where it can be handled most efficiently—in its databases. Interested users can then query this data directly or choose to materialize the data as RDF files.     

Synthetic Biology Makes Polymer Materials Count

Synthetic biology applies engineering concepts to build cellular systems that perceive and process information. This is achieved by assembling genetic modules according to engineering design principles. Recent advance in the field has contributed optogenetic switches for controlling diverse biological functions in response to light. Here, the concept is introduced to apply synthetic biology switches and design principles for the synthesis of multi‐input‐processing materials. This is exemplified by the synthesis of a materials system that counts light pulses. Guided by a quantitative mathematical model, functional synthetic biology‐derived modules are combined into a polymer framework resulting in a biohybrid materials system that releases distinct output molecules specific to the number of input light pulses detected. Further demonstration of modular extension yields a light pulse‐counting materials system to sequentially release different enzymes catalyzing a multistep biochemical reaction. The resulting smart materials systems can provide novel solutions as integrated sensors and actuators with broad perspectives in fundamental and applied research.     

Local Effects on Airway Inflammation and Systemic Uptake of 5 nm PEGylated and Citrated Gold Nanoparticles in Asthmatic Mice

Nanotechnology is showing promise in many medical applications such as drug delivery and hyperthermia. Nanoparticles administered to the respiratory tract cause local reactions and cross the blood–air barrier, thereby providing a means for easy systemic administration but also a potential source of toxicity. Little is known about how these effects are influenced by preexisting airway diseases such as asthma. Here, BALB/c mice are treated according to the ovalbumin (OVA) asthma protocol to promote allergic airway inflammation. Dispersions of polyethylene‐glycol‐coated (PEGylated) and citrate/tannic‐acid‐coated (citrated) 5 nm gold nanoparticles are applied intranasally to asthma and control groups, and (i) airway resistance and (ii) local tissue effects are measured as primary endpoints. Further, nanoparticle uptake into extrapulmonary organs is quantified by inductively coupled plasma mass spectrometry. The asthmatic precondition increases nanoparticle uptake. Moreover, systemic uptake is higher for PEGylated gold nanoparticles compared to citrated nanoparticles. Nanoparticles inhibit both inflammatory infiltrates and airway hyperreactivity, especially citrated gold nanoparticles. Although the antiinflammatory effects of gold nanoparticles might be of therapeutic benefit, systemic uptake and consequent adverse effects must be considered when designing and testing nanoparticle‐based asthma therapies.     

An extended techno-economic analysis of the utilization of glycerol as an alternative feedstock for methanol production

Glycerol is a by-product of biodiesel production and may become an environmental problem. This paper investigates the utilization of glycerol as alternative feedstock for methanol production. A mathematical model of the methanol plant encompassing the steam reforming and methanol synthesis units is employed to generate data for an economic analysis involving two comparative cases: the conventional operation of the plant using only natural gas and the operation with partial substitution of the natural gas by glycerol. The results indicate that the glycerol injection can reduce the total natural gas consumption by about 11% for a given fixed methanol production. A breakeven analysis procedure is applied to determine the limit price of glycerol that makes this operation economically feasible. Based on a natural gas price of 10.13 US$/MMbtu, this analysis demonstrates that glycerol injection is feasible if its price is lower than 78.5 US$/t. Additionally, a sensitivity analysis indicates that a variation of 10% on the natural gas price causes a 26% variation on the glycerol breakeven point. The complete set of data indicates that it is possible to explore periods of glycerol low prices to reduce the operational costs of methanol plants that suffer from high natural gas prices.     

Bio-inspired Active System Identification: a Cyber-Physical Intelligence Attack in Networked Control Systems

Mobile Networks and Applications - From the point of view of the control theory, the literature indicates that stealthy and accurate cyber-physical attacks on Networked Control System (NCS) must be...