Effect of hybridization and compatibilization on the mechanical properties of recycled polypropylene‐hemp composites

Hemp fibers and particles, with different sizes and contents, were used to make hybrid composites based on recycled polypropylene (PP). In particular, the effect of maleated polypropylene (MAPP) addition on the morphology and mechanical properties is reported. The results show that better adhesion is obtained with MAPP addition. In general, fiber content and size had a substantial effect on the tensile, flexural, torsion, and impact properties of the resulting composites. Although, adding MAPP to the samples improved the impact strength of the composites, the values were always lower than neat PP. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

Determination of Capacity Benefit Margin in Multiarea Power Systems Using Particle Swarm Optimization

Available transfer capability (ATC) is a key index of the remaining capability of a transmission system for future transactions. To calculate the ATC between two areas in an interconnected power system, capacity benefit margin (CBM) is one of the indexes that need to be assessed. CBM ensures security of system operation when the system faces generation deficiency in some areas. In this paper, three new methods are introduced which reflect different objectives for CBM assessment. This provides more flexibility of choices for market participants. In the proposed methods, CBM determination is formulated as an optimization problem and particle swarm optimization (PSO) method is used to solve the problem. The numerical results for modified IEEE reliability test system are presented to demonstrate the effectiveness of the proposed approaches.     

Cellulose nanofibers from the skin of beavertail cactus,Opuntia basilaris,as reinforcements for polyvinyl alcohol

In this study, the skin of the beavertail cactus, Opuntia Basilaris, was used for the isolation of cellulose nanofibers using a chemo‐mechanical technique. It was shown that the skins had a relatively high cellulose content, whereas their lignin content was low. Fourier transform infrared spectroscopy and X‐ray diffraction proved that the isolation of cellulose nanofibers from the amorphous components of the skins was performed successfully. The cactus skins were also shown to have a high content of calcium oxalate crystals. Morphological observations proved that the isolated cellulose fibers had diameters in the range of 10–50 nm. It was shown that the addition of nanofibers increased the modulus and strength of the polyvinyl alcohol matrix significantly, whereas the elongation at break decreased. Thermogravimetric analysis proved that: (i) isolated nanofibers had higher thermal stabilities than the cactus skins, and (ii) inclusion of nanofibers increased the stability of polyvinyl alcohol noticeably. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 42499.     

On hyperbolic laws of capacitor discharge through self‐timed digital loads

A new model to predict the dynamic behavior of a self‐timed autonomous digital system powered by a capacitor is derived. The model demonstrates the hyperbolic shape of the discharging process on the capacitor. It allows a symbolic analysis of the discharging process for complex digital loads comprised of series (stack) and parallel configurations of digital circuits. For example, for a stack configuration, important non‐trivial relationships between the hyperbolic discharging rates have been derived based on the knowledge of the velocity saturation index (alpha) of the semiconductor devices used in the digital part. For a realistic (modern complementary metal oxide semiconductor (CMOS) devices) value of alpha = 1.5, the discharging process for a stack of two identical circuits proceeds nearly three times slower than that of any of the stand‐alone circuits. This shows a potential way of extending the lifetime of the energy sources by means of stacking self‐timed circuits. Although the analysis is based on configurations consisting of ring oscillators in CMOS technology, the analysis method can be extended to other types of self‐timed systems and other semiconductor technologies in which the instantaneous switching activity of the digital load is determined by the instantaneous voltage levels provided by the capacitive power transfer mechanism. The analytical derivations have been validated by simulations and experiments carried out with real hardware. © 2014 The Authors. International Journal of Circuit Theory and Applications published by John Wiley & Sons, Ltd.     

Nano-sized manganese oxides as biomimetic catalysts for water oxidation in artificial photosynthesis: a review

There has been a tremendous surge in research on the synthesis of various metal compounds aimed at simulating the water-oxidizing complex (WOC) of photosystem II (PSII). This is crucial because the water oxidation half reaction is overwhelmingly rate-limiting and needs high over-voltage (approx. 1 V), which results in low conversion efficiencies when working at current densities required for hydrogen production via water splitting. Particular attention has been given to the manganese compounds not only because manganese has been used by nature to oxidize water but also because manganese is cheap and environmentally friendly. The manganese–calcium cluster in PSII has a dimension of about approximately 0.5 nm. Thus, nano-sized manganese compounds might be good structural and functional models for the cluster. As in the nanometre-size of the synthetic models, most of the active sites are at the surface, these compounds could be more efficient catalysts than micrometre (or bigger) particles. In this paper, we focus on nano-sized manganese oxides as functional and structural models of the WOC of PSII for hydrogen production via water splitting and review nano-sized manganese oxides used in water oxidation by some research groups.     

Creating shared value to redesigning IT-service products using SYRCS; Diagnosing and tackling complex problems

The existence of different stakeholders in a system, the actual and potential contradictions that may not be identified, and the long-term consequences of each decision are significant challenges in the process of developing a system. Information technology-based services are among the systems that usually interact with users and have a significant impact on their environment. The present study attempts to properly understand and develop the services of an intercity payment system in Iran. After recognizing the problem step by step, an innovative methodology was designed to structure the problem. In the early stages, using one of the critical frameworks after identifying stakeholders, research on the system was conducted, and interviews were identified, which are involved and affected people by the system. Critiques of stakeholders became to viable option during the specified process. Additionally, inspired by the soft operational research (OR), the obtained results were examined in terms of the executive contradictions, and then to evaluate and select the correct options, the long-term consequences of each decision were identified using Multi Attribute Decision-Making. Moreover, the evaluation of options for different stakeholders was done by their representatives using their related criteria to select the best options from the opposing options. Ultimately, the presented methodology is designed to provide a slow movement from qualitative to quantitative form. Consequently, based on creating shared value, the product has been redesigned to satisfy all stakeholders.

     

Evolution of bubble size distribution,number density,and shape in semi-batch vertical gas–liquid Taylor vortex flow

Bubble size distribution and bubble ellipticity were measured as a function of axial position in a vertically oriented semi-batch gas–liquid Taylor vortex reactor with varying gas flow rate and inner cylinder rotation speed producing axial Reynolds numbers in the range 23.8–119 and azimuthal Reynolds numbers up to 4.2 × 10⁴. The mean bubble size increases monotonically with axial distance from the bottom of the reactor at the location of gas injection. The functional form of the growth of the mean bubble size with axial position depends upon the azimuthal Reynolds number. Specifically, when the azimuthal Reynolds number is less than 1.3 × 10⁴, the mean bubble size increases linearly with axial distance from the bubble injection point. In contrast, for azimuthal Reynolds numbers greater than this critical value, the mean bubble size increases with axial distance in a sigmoidal manner.     

Sustainable Dimethyl Carbonate Production from Ethylene Oxide and Methanol

A large-scale dimethyl carbonate (DMC) production process from ethylene oxide (EO), CO₂, and methanol was simulated and optimized. Unlike most industrial processes of DMC production, the direct conversion of EO and CO₂ to ethylene carbonate (EC) and EC transesterification to DMC were performed in a single reactor. The reaction volume and the reactor operating pressure were selected as decision variables and evaluated. The key performance parameters, e.g., conversion per pass and CO₂ intensity, were compared with conventional commercialized routes or novel promising processes in the literature.     

HMR-vid: a comparative analytical survey on human motion recognition in video data

Multimedia Tools and Applications - According to the rapid spread of multimedia data and online observations by users, the importance of researching on machine vision also, analyzing and automatic...