The impact of home freezing on the sensory characteristics of ready-to-use leafy vegetables

BACKGROUND: Owing to the increasing trend of consumption of ready‐to‐use leafy vegetables, the necessity of determining the best conditions for their frozen storage and the considerable impact of freezing on their sensory attributes, research was carried out to determine the best freezing temperature and storage time for a mixture of Allium ampeloprasum, Lepidium sativum and Stureia hortensis. RESULTS: The results for freezing temperature at three different storage times showed that colour and overall acceptability at ? 18 °C were always ranked first (P < 0.05), while taste at ? 18 °C was ranked first on days 120 and 150. The results for frozen storage time at three different temperatures indicated that colour, taste and acceptability were not significantly different. CONCLUSION: Overall, the results of this research indicated that the sensory attributes of leafy vegetables during 180 days of frozen storage were affected mainly by freezing temperature rather than frozen storage time. Copyright © 2010 Society of Chemical Industry     

Two Efficient Dual-Band and Wide-Band Low-Power DCO Designs Using Current Starving Gates,DCV and Reconfigurable Schmitt Triggers in 180 nm

Digitally controlled oscillators are the main cores in all-digital phase-locked loops (ADPLL), which are important for determining the range of frequency and power consumption in ADPLLs. In the conventional digitally controlled oscillator (DCO) designs, one single band of operation is assigned to the DCO. The following paper presents a new approach in the design of DCOs, which works in dual-band and wide-band modes with a control unit. In dual-band mode, the DCO works in two different ranges of frequencies simultaneously via digital control bits. The wide-band DCO (WBDCO) works in one wider range of frequencies consecutively. It seems that in the wide-band DCO, the gap width for the dual-band DCO (DBDCO) is zero. The previously mentioned designs allow the designer to have standard frequencies with the help of direct or multiplied frequencies. So, we can have a trade-off between power and performance. This means that we can have low power consumption in low-frequency applications and vice versa. The proposed designs are based on using digitally controlled capacitors, current starving gates and Schmitt triggers in critical points of the DCO loop, while preserving coarse and fine tunings. The non-delay linearity factors are clearly investigated and resolved with the use of a new combined control unit. The simulations of the proposed designs are performed in Hspice with a voltage of \(\mathrm{VDD}=1.8\) v in 180 nm CMOS technology for 64- and 128-bit input coarse codes. Our simulation and evaluation results showed that in the dual-band DCO, a 14.8 ps jitter was calculated at 134 MHz with 1.2131 mW power consumption, while in the wide band with overlap mode, a 68.7 ps jitter was measured at 184.61 MHz with 1.604 mW power consumption. Our designs are proper for reconfigurable and multi-standard ADPLL designs.     

Influence of Static Low Electromagnetic Field on Copper Corrosion in the Presence of Multispecies Aerobic Bacteria

The effects of low electromagnetic field(EMF)( B = 2 mT) on the corrosion of pure copper in the absence and presence of multispecies marine aerobic bacteria were investigated in this work. The results showed that EMF has an inhibitory effect on copper metals and decreases the corrosion rate of copper metals in sterile artificial seawater. However, microbiologically influenced corrosion of Cu was increased in the presence of electromagnetic field due to its effect on the biofilm morphology and structure. EMF reduced the growth rate of bacteria and decreased bacterial attachment, thereby forming a heterogeneous and non-stable biofilm on the Cu surface in the presence of EMF. Moreover, the biofilm was dispersed throughout the surface after 7 days, whereas the scattered bacteria were observed on the surface after 10 days. Confocal laser scanning microscopy images showed large and deep pits on the surface in the presence of EMF and confirmed the acceleration of Cu corrosion in the presence of EMF and multispecies bacteria. Furthermore, XPS and FTIR results demonstrated that the corrosion products and metabolic by-products were significantly changed in the presence of EMF.     

Mathematical-Thermodynamic Prediction and Kinetics of Eta Phase Formation in Fe–Ni-Based Superalloys

Time–temperature–precipitation diagram of eta phase formation was established for an Fe–Ni based superalloy by means of mathematical-thermodynamic analysis, kinetic investigation, and microstructural observation. The eta phase started to precipitate at the expense of the γ′ phase after prolonged aging. On the basis of thermodynamic prediction, the interaction between Gibbs free energy of eta phase formation and activation energy for diffusion of elements, especially titanium, was considered. The tip of TTP diagram was obtained at 817 °C, on the basis of mathematical-thermodynamic prediction, and 825–840 and 840 °C, on the basis of microstructural evolution and kinetic analysis, respectively. Kinetic investigations predicted that the eta transformation started with diffusion of Ti into Ni. This indicated that, with the progress of transformation, as n in Avrami’s equation predicts, other eta formation mechanisms such as γ′ to eta transformation, instant nucleation from the matrix, coincidence of eta lamellas, etc. increased n and activation energy.     

Multi-criteria evolutionary optimization of a traffic light using genetics algorithm and teaching-learning based optimization

Today, the development of urbanization and increasing the number of vehicles has resulted in displeased consequences like traffic congestion and vehicle queuing. The vast majority of countries in the world encounter the challenge of the explosive rise in traffic demand. In this regard, it is necessary to meet traffic demand in transport networks, especially in metropolitans. In traffic management and shortening the trip duration, traffic lights on the signalized intersections play an essential role in urban pathways. This work provides a multi-criteria decision-making method for optimum traffic light control in an isolated corner. The main idea involves establishing a set of sub-optimal solutions for traffic light timing and selecting the best one among the diverse solutions. We have mathematically modelled the problem as an optimization problem to achieve an optimal solution with less waiting time for vehicles in intersections and the lowest cost. Genetic algorithm (GA) and Teaching-Learning-based Optimization (TLBO) are utilized for each phase to create a set of suitable timing scenarios. The Technique for Order of Preference by Similarity to Ideal Solution (TOPSIS) method is used to identify the best scenario, considering both waiting vehicles and traffic capacity as decision criteria. Its efficiency has been demonstrated over three different traffic volumes. Also, in a real-world implementation, its practical capability has been approved at a crossroads in Mashhad, Iran. The simulations indicate the improvement in the number of vehicles waiting behind the crossroad and the traffic capacity by 10% and 6.76% compared to the existing signal timing of the studied intersection, respectively.     

On the time‐frequency symbol density of FBMC/QAM systems

Filter bank multicarrier (FBMC) systems suffer from an inherent interference, which needs to be eliminated at the detection process. Orthogonal frequency division multiplexing/offset quadrature amplitude modulation (OFDM/OQAM) is a well‐known FBMC system, which transmits real‐valued symbols. In OFDM/OQAM, the time and frequency spacing between adjacent transmitted symbols are organized such that the inherent interference becomes pure imaginary and can be removed by a real‐taking operation. Although OFDM/OQAM provides the maximal bandwidth efficiency, it falls short in handling the spatial multiplexing techniques in multi‐input multi‐output channels. In this regard, those modified FBMC systems, which transmit complex QAM symbols (FBMC/QAM) are used to support the spatial multiplexing techniques. In this article, we present a novel matrix formulation for the FBMC/QAM transmission procedure. On the basis of this presentation, we show that the maximal achievable time‐frequency symbol density of FBMC/QAM, with the ability of perfectly removing the interference, is equal to that of the primer OFDM/OQAM.     

Simulation of mixed electroosmotic/pressure-driven flows by utilizing dissipative particle dynamics

In this paper, we present an extension of dissipative particle dynamics method in order to study the mixed electroosmotic/pressure-driven micro- or nano-flows. This method is based on the Poisson–Boltzmann equation and has a great potential to resolve the electric double layer (EDL). Hence, apart from studying the bulk flow, it also provides a strong capability in order to resolve the complex phenomena occur inside the EDL. We utilize the proposed method to study the pure electroosmotic and also the mixed electroosmotic/pressure-driven flow through the straight micro-/nano-channels. The obtained results are in good agreement with the available analytical solutions. Furthermore, we study the electroosmotic flow and motion of DNA molecules through a T-shaped micro-channel. We show that neglecting the EDL and utilizing the slip wall boundary condition model can result in crucially misleading hydrodynamic characteristics if the EDL is comparable to the width of the channel. Finally, we utilize the presented method in order to study the complex flow patterns, which are created due to the heterogeneous distribution of the electric potential of the walls. These complex flow patterns usually are utilized in order to enhance the efficiency of mixing process in micro-/nano-length scales. In addition, we show that they can also be utilized effectively in order to separate the different macro-molecules such as polymers, DNA molecules and so on, according to their length of chain.     

Green polycarbonates prepared by the copolymerization of CO2 with epoxides

Polycarbonates can be prepared by the copolymerization of epoxides with carbon dioxide as an inexpensive, abundant, nontoxic, and renewable feedstock. This review covers the synthesis, the physicochemical properties, and the growing applications of this class of green polymers. The review has been conceived to provide a useful tool for the researchers who are new to this field, as well as to offer an updated overview for those who are already actively working on this topic. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 41141.