Effects of Gellan-Based Edible Coating on the Quality of Fresh-Cut Pineapple During Cold Storage

The effects of gellan-based [gellan gum 0.56 % (w/v), glycerol 0.89 % (w/v) and sunflower oil 0.025 % (w/v)] edible coating on the respiration rate, physico-chemical properties and microbiological and sensory quality of fresh-cut pineapple during 16 days of storage (5?±?1 °C, 85?±?10 % RH) were evaluated. Uncoated fresh-cut pineapple was stored under the same condition and served as the control. For cross-linking reaction which was necessary for gel formation of gellan gum, a 2 % (w/v) calcium chloride solution that contained 1 % (w/v) ascorbic acid and 1 % (w/v) citric acid (as antibrowning agents) was used. The results obtained show that the respiration rate and weight loss of gellan-based coated samples were significantly (p?<?0.05) lower than those of the uncoated samples during 16 days of storage at 5 °C. In addition, coated samples significantly (p?<?0.05) maintained the firmness and colour of fresh-cut pineapple during low-temperature storage as compared to uncoated samples. The results obtained in this study also indicate that pH, titratable acidity and total soluble solids of coated and uncoated samples showed little changes during 16 days of storage at 5 °C. Gellan-based formulation did not show any antimicrobial effect, and no significant (p?>?0.05) differences were found among total plate counts and yeast and mould counts for coated and uncoated samples. Total plate counts and yeast and mould counts for coated and uncoated samples reached 10⁶ CFU/g (limit of shelf life acceptance for fruit-based products recommended by the Institute of Food Science and Technology in the UK) after 12 days of storage at 5 °C. In addition, the scores for all sensory characteristics at day 12 were significantly (p?<?0.05) higher in coated samples as compared to control. Therefore, the results obtained in this study indicate that gellan-based edible coating formulation has the potential to maintain the quality of fresh-cut pineapple during low-temperature storage for about 12 days.     

Monitoring of Zn(II), Cd(II), Pb(II) and Cu(II) During Refining of Some Vegetable Oils Using Differential Pulse Anodic Stripping Voltammetry

In this study, a novel approach has been developed using differential pulse anodic stripping voltammetry (DPASV) for the simultaneous determination of Zn(II), Cd(II), Pb(II) and Cu(II) in edible oils at hanging mercury drop electrode. The microwave digestion of oil samples was carried out with concentrated HNO₃ and H₂O₂. KNO₃ was used as a supporting electrolyte. The experimental conditions optimized such as deposition time, stirring rate and size of mercury drop were 300 s, 600 rpm and 10 mm², respectively. The method was applied to quantify Zn(II), Cd(II), Pb(II) and Cu(II) in crude and refined hazelnut, corn, sunflower and olive oils. During refining of different vegetable oils, the removal efficiencies of Zn(II), Cd(II), Pb(II) and Cu(II) were calculated as 98.20–99.91, 98.50–99.90, 95.26–99.76 and 95.93–99.92 %, respectively. The limits of detection for Zn(II), Cd(II), Pb(II) and Cu(II) were 2.1?×?10^?8, 8.7?×?10^?10, 7.1?×?10^?9 and 3.4?×?10^?9 and the limits of quantification were 6.8?×?10^?8, 2.9?×?10^?9, 2.3?×?10^?8 and 1.1?×?10^?8 M with linear regression coefficients (R ²) of 0.9930, 0.9928, 0.9893 and 0.9931, respectively. It was observed that the above metals in crude and refined vegetable oils could be determined simultaneously by the DPASV method.     

Cadmium Ions Determination in Sea Food Samples Using Dipyridyl-Functionalized Graphene Nano-sheet

In this work, graphene nano-sheets was modified by dipyridyl amine group and used as a novel sorbent for selective separation and preconcentration of cadmium ions. The sorbent was characterized by infrared spectroscopy, transmission electron microscopy, thermal analysis, and elemental analysis. The application of this sorbent was investigated in determination of cadmium ions in sea food samples by flame atomic absorption spectrometry. The effective parameters on adsorption and desorption of cadmium were optimized. The limit of detection, the relative standard deviation and the recovery of the established method were found to be 0.19 ng mL^?1, 1.6 %, and 99.1 %, respectively. The method was validated using various standard reference materials and was applied for cadmium determination in sea food sample.     

Determination of Sulfonamides in Chicken Meat by Magnetic Molecularly Imprinted Polymer Coupled to HPLC-UV

In this work, Fe₃O₄ magnetic nanoparticles were synthesized and modified by a molecularly imprinted polymer for easy and selective extraction and determination of sulfonamides in chicken meat samples. Imprinted polymer magnetic nanoparticles were characterized by Fourier transform infrared spectroscopy, X-ray diffraction pattern, thermal analysis, and scanning electron microscope micrograph. The template was removed by methanol elution. The effective parameters on extraction and determination of sulfonamides on the sorbent such as eluent type, extraction solvent, and adsorption and desorption times were optimized. Sulfonamide separation and determination were performed by high-performance liquid chromatography–UV. The linear ranges for sulfonamides were 0.5–150 μg/L and the limits of detection were 0.1–0.5 μg/L. Relative standard deviations were within 4.3–5.4 %. The method showed good selectivity for extraction of sulfonamides in real samples.     

Characterization of water-soluble extracts from hot-pressed poplar

Thermal modification of wood constituents occurs upon hot-pressing of flakes during consolidation of oriented strand board (OSB). Hence, the effects of hot-pressing of hybrid poplar on water-soluble extractives were studied. Poplar veneers were pre-conditioned to 0 or 8 % moisture content and subsequently hot-pressed at 150, 200 or 250 °C. Aqueous extracts were characterized by conventional chemical methods in conjunction with chromatography (HPLC and SEC), mass spectrometry (ESI–MS) and spectroscopy (FTIR) analysis. Water-soluble fractions were markedly influenced by thermal compression treatment at 250 °C compared to the lower temperatures. Chromatographic results indicate that water-soluble extractives content increases with temperature while the degree of polymerization decreases with detection at low temperature levels. FTIR spectroscopic analysis indicates changes in aqueous-extracts composition of wood monosaccharides (hemicelluloses), meanwhile ESI–MS detected xylo-oligosaccharides. These results clearly show that heat treatment dictated the changes in each water-soluble extractive component and they respond independently with different treatment.     

Repair technique of pre-cracked reinforced concrete (RC) beams with transverse openings strengthened with steel plate under sustained load

This paper presents a repairing technique of the steel plate that effectively strengthen RC members, control both the failure modes and the stress distribution around the beam chords and enhance the serviceability of pre-cracked RC beams with openings. Furthermore, to evaluate the usage of a temporary pre-stressed force that was applied on the RC beam so as to close all of the presence shear cracks before the steel plate application. Two un-strengthened control beams, five beams that were pre-cracked before the application of the steel plate, and one beam that was strengthened without pre-cracking were tested. Cracking was first induced, followed by repair using various strengthening technique, and then the beams were tested to failure. The advantages of the shear strengthening of RC beams that were obtained using this technique are based on the closing of all the existing cracks around the openings via epoxy injection. The results show that both the pre-existing damage level and the steel plate strengthening have a significant effect on strengthening effectiveness and failure mode at the ultimate strength. An analytical equation for predicting the shear strength of pre-damaged RC beams with circular openings was then proposed, and the obtained results later compared with those from the tests, results were in accordance.     

An efficient hexagonal switched beam antenna structure based on Fabry-Perot cavity leaky-wave antenna

A novel design of switched beam antenna (SBA) system based on Fabry-Perot cavity leaky-wave antenna (FPC LWA) is designed and fabricated for base station operating in the unlicensed ISM central frequency band at 5.8 GHz of the wireless local area network (WLAN) standard. The proposed SBA is designed with hexagonal shape of FPC LWA Arrays in order to get 360° of coverage. The single element of FPC LWA array is composed of a patch antenna and covered by a Partially Reflective Surface (PRS), which is composed of a Metal Strip Grating and printed on a high permittivity Superstrate. First, the Transmission Line Model of FPC LWA is introduced to analyse and calculate the far-field components in E- and H planes by using the Transverse Equivalent Network. This approach is then compared with other full wave’s commercial software such as Ansoft HFSS and CST Microwave Studio. Second, a parametric study is performed to evaluate the effect of the angle formed by the two successive FPC LWA on the radiation efficiency of the activate sector. To examine the performance of the proposed SBA, experimental prototype was fabricated and measured. As a result, multiple orthogonal beams (six beams) of 10 dBi of gain with low Side Lobes Level and 360° of coverage are produced. This SBA structure is suitable for WLAN communication systems.     

Experimental characterisation of PD SOI MOSFET devices fabricated with diamond-shaped body contact

The design of diamond-shaped body-contacted (DSBC) devices using standard layers in a 0.35?µm silicon-on-insulator (SOI) complementary metal-oxide-semiconductor process is described in this article. The technology is based on a manufacturable partially depleted SOI process targeted for radio frequency applications. The experimental measurements of drain induced barrier lowering for the fabricated DSBC structure showed suppression of floating body effects (FBE) at the promising rate of 24?mV/V. The measurement results confirmed current drive (I _DS) improvement by 25% at V _DS?=?1.5?V and V _GS?=?1.5?V compared to conventional body-tied-source (BTS) device. A constant and steady output conductance (g _DS) in the saturation region was observed for the DSBC structure. The gate trans-conductance (g _m) is improved by 34% at V _DS?=?1.5?V and V _GS?=?1.5?V compared to conventional BTS device. Three-dimensional device simulation provides insight on FBE suppression and channel current improvement. Experimental results confirmed the area efficiency of the DSBC structure and its excellent current drive performance.     

A fine-grain distortion and complexity aware parameter tuning model for the H.264/AVC encoder

Most existing video encoders currently used in mobile applications are unable to gracefully degrade their output quality as the battery life nears its end. In other words, they cannot manage power consumption to efficiently utilize the available power resources. To be able to effectively adapt to changes in the encoder′s software and hardware platforms, especially due to the power limitations of mobile devices, the effect of encoder parameters on the encoding quality and power consumption has to be represented using a Rate–Distortion–Complexity (R–D–C) model. Most existing R–D–C models only consider macroblock level parameters, and overlook other higher level parameters that may have a more significant impact on complexity. In this paper, the distortion and complexity of the H.264/AVC encoder is controlled considering a subset of higher level encoding parameters consisting of search range, number of reference frames, and motion vector resolution. First, the complexity of full and fast motion estimation methods is modeled in an implementation and platform independent manner. Then, using this complexity model, a common encoding parameter setting table is derived, which leads to the least amount of distortion for each complexity condition. Finally, a complexity control mechanism is proposed which tunes the encoding parameters in a real-time manner. The proposed model can be combined with other existing macroblock level models in order to design a two-phase fine grain complexity controller. Simulation results indicate that when our method is integrated with the direct resource allocation (DRA) approach, performance increases by an average of 1.02 dB and 1.06 dB for full and fast motion estimation approaches, respectively.     

WSANRep, WSAN Reputation-Based Selection in Open Environments

Wireless Sensor and Actuator Networks (WSAN) are becoming more and more relevant and are likely to spread everywhere, due to their numerous applications and benefits. In fact, they are a key element in the vision of the so called Internet of Things. Nevertheless, the lack of central control and the existence of incentives for cheating lead to the necessity of defining mechanisms for identifying well-behaving WSANs. Reputation based solutions have been suggested in the literature in order to cope with these situations, but most of them were focused on finding a specific most trustworthy sensor, capable of provisioning a requested service. Our work, however, is oriented to provide a mobile user with an accurate reputation-based mechanism allowing her to select, amongst a set of available WSANs, the most reputable one, according to the recommendations given by other users. Thus, the mobile user can build her own opinion and consequently decide which is the best WSAN to interact with. This decision will be based in her own criteria, which might be different from other users of the same service. In order to prevent the abuse of the proposed reputation system, we suggest a mechanism avoiding multiple recommendations from the same user in a specific time frame. Additionally, we handle certain privacy issues by hiding the real identity of a user behind a group. The experiments performed show the accuracy, scalability and robustness of our proposal, called WSANRep, within several scenarios, considering the existence of malicious recommenders and malicious service providers.