Dynamic finite element analysis of a gradient elastic bar with micro-inertia

We study the dynamic behavior of a first strain gradient elastic bar with micro-inertia by means of the finite element method. The partial differential equation describing the motion of the bar expressed in terms of displacement is of fourth order with respect to the spatial variable, therefore, for the standard Galerkin formulation, Hermite elements are required. Consistent mass matrices are employed. The results are validated by comparison with some special cases where the exact solutions are derivable. Dispersion relations for the longitudinal waves are also derived. The effect of micro-inertia in the dynamic response of the bar is analyzed and comparisons are made with the classical elastic case. It is found that the micro-inertia parameter considerably affects the dynamic response of the bar and the dispersion characteristics of longitudinal waves.     

Examining the thermal behaviour of novel aromatic polybenzoxazine blends containing an organophosphorous compound and polyhedral oligomeric silsesquioxane reagents

2,2‐Bis(3,4‐dihydro‐3‐phenyl‐2H‐1,3‐benzoxazine)propane (BA‐a) is blended with various commercial polyhedral oligomeric silsesquioxane (POSS) reagents and an organophosphorous compound, bis(4‐hydroxyphenyl)phenylphosphine oxide (BPPO), at a range of loadings (1–10 wt%). The influence of the additives on the onset and rate of polymerisation of BA‐a is examined using differential scanning calorimetry. An initial screen of blends containing various additives (5 wt%) shows that a combination of aminoethylaminopropyl isobutyl POSS (AEAP) and BPPO has the greatest effect on reactivity with a reduction in reaction onset of some 65 K and an increase in glass transition temperature of 18 K when compared with the BA‐a homopolymer. The activation energy for the polymerisation of BA‐a containing 5 wt% AEAP is determined to be 84–88 kJ mol^?1 (using Kissinger and Ozawa kinetic models), with a first‐order rate constant of 1.9 × 10⁸ s^?1. The thermal stability of the cured blends containing 5 wt% flame retardant is examined using thermogravimetric analysis, and both onset of degradation and char yield are increased by 15 K and 5%, respectively, when compared with the BA‐a homopolymer. © 2016 Society of Chemical Industry     

Smoking of Fish and Seafood: History,Methods and Effects on Physical,Nutritional and Microbiological Properties

Smoking technology is increasingly used nowadays to impart particular organoleptic characteristics to fishes and as a means of maintaining and extending the shelf-life of these perishable products. The antimicrobial and antioxidant effects of smoking have been recently studied in depth, and various methods of smoking are applied worldwide, focusing mainly on species groups such as salmon and other salted fish and seafood. Despite the obvious advantages of the process, there are also a number of hazards related to the consumption of smoked products. One of the most representative examples is the outbreak of various cancers common in countries such as Nigeria and Baltic countries due to the high content of foods in polycyclic aromatic hydrocarbons produced as a by-product of the process. Furthermore, many studies have demonstrated that smoking with pyrolytic flue gases causes environmental pollution. These facts can have a significant impact on the acceptance of these products by consumers. In this review article, the objective is to describe synoptically the general methods of fish smoking, to report both advantages and disadvantages resulting from these methods, to present safety aspects of smoking both with regard to microbiological and chemical issues and to provide some representative examples of smoked fish applications both in tabular and figural form.     

Microfaunal indicators, Ciliophora phylogeny and protozoan population shifts in an intermittently aerated and fed bioreactor

Microfauna community structure was examined in the mixed liquor of a bench-scale bioreactor equipped with an intermittent aeration and feeding system. The reactor was operated under an intermittent aeration of 25 min in every 1 h and varying feeding conditions (0.264, 0.403 and 0.773 kg BOD(5)/m(3) d). A total of 14 protozoan and metazoan taxa were identified by microscopic examination. Sessile ciliates, followed by crawling ciliates, were the major protozoan groups under 0.403 kg BOD(5)/m(3) d organic loading conditions, while sessile ciliate population was remarkably increased under an organic loading of 0.773 kg BOD(5)/m(3) d. Principal Component Analysis and Pearson correlation coefficient tests were performed in order to reveal relationships between microfauna community and operational parameters. Ciliophora specific-18S rRNA gene clone library was constructed to identify ciliate diversity under 0.773 kg BOD(5)/m(3) d organic loading conditions. Ciliophora diversity consisted of members of Aspidiscidae, Epistylidae, Opisthonectidae and Vorticellidae, with the majority of the clones being associated with the species Vorticella fusca. At least one novel phylogenetic linkage among Ciliophora was identified. Comparisons made after molecular characterization and microscopic examination of Ciliophora community showed that the estimation of broad ciliate groups is useful for ecological considerations and evaluation of the operational conditions in wastewater treatment plants.     

Simultaneous determination of pesticides using a four-band disposable optical capillary immunosensor

The development of a four-band capillary optical immunosensor for the simultaneous determination of mesotrione, hexaconazole, paraquat, and diquat is described. Four distinct bands (each corresponding to a different analyte) are created in the internal walls of a plastic capillary by immobilizing protein conjugates of the analytes. To perform the assay, the capillary is filled with a mixture of anti-analyte-specific antibodies together with a standard or sample containing the analyte(s). After a short incubation, a mixture of the appropriate second antibodies labeled with fluorescein is introduced into the capillary. To measure the fluorescence intensity bound onto each band, the capillary was scanned, perpendicularly to its axis, by a laser light beam. Part of the emitted photons were trapped into the capillary walls and waveguided to a photomultiplier placed at the one end of the capillary. The analytical characteristics of the assays of mesotrione, paraquat, diquat, and hexaconazole were as follows: detection limits of 0.04, 0.06, 0.09, and 0.10 ng/mL, respectively; dynamic ranges up to 9, 6, 12, and 15 ng/ mL, respectively, intra- and interassay CVs less than 10%. The analytical characteristics of the assays were comparable with those of the corresponding single-analyte fluoroimmunoassays performed in microtitration wells, proving the ability of the proposed immunosensor for reliable multianalyte determinations. Moreover, the combination of low-cost disposable plastic capillary tubes with the low consumption of reagents, the short assay time, and the multianalyte feature of the proposed immunosensor indicates its potential for environmental analysis.     

Junction-Based Geographic Routing Algorithm for Vehicular Ad hoc Networks

Vehicular Ad hoc Networks have attracted the interest of the scientific community, since many issues remain open, especially in the research area of routing techniques. In this work we propose a new position-based routing algorithm called Junction-Based Routing. The algorithm makes use of selective greedy forwarding up to the node that is located at a junction and is closer to the destination. If a local optimum is reached, a recovery strategy is applied, the key point of which is our proposed minimum angle method. We evaluate the performance of our routing protocol in real city topology. The simulated scenarios use obstacle modelling and several different Physical layer settings. Simulation results show that our proposal achieves superior performance compared to the well-known Greedy Perimeter Coordinator Routing algorithm.     

Optimized 90° Polarization Shift Step Twists for Ku,K and Ka Bands

Optimized models for 90° polarization shift step twists for Ku, K and Ka bands are presented. The cross-section of the waveguide employed is similar to that of a rectangular one, with the difference that the walls of the shorter side are part of a circular one with the proper diameter. The optimized models have been found using the CST Microwave Studio simulation tool and in all cases the return loss is kept below -20 dB for a wide range of frequency spectrum. Two examples are given, one for Ku band and the other for K and Ka ones.     

Novel Pipelined Architecture for Efficient Evaluation of the Square Root Using a Modified Non-Restoring Algorithm

The square root is a basic arithmetic operation in image and signal processing. We present a novel pipelined architecture to implement N-bit fixed-point square root operation on an FPGA using a non-restoring pipelined algorithm that does not require floating-point hardware. Pipelining hazards in its hardware realization are avoided by modifying the classic non-restoring algorithm, thus resulting in a 13% improved latency. Furthermore, the proposed architecture is flexible allowing modification as per individual application needs. It is demonstrated that the proposed architecture is approximately four times faster than its popular counterparts and at the same time it consumes 50% less energy for envelope detection at 268 MHz sampling rate.