Performance of the sulfonated poly ether ether ketone proton exchange membrane modified with sulfonated polystyrene and phosphotungstic acid for microbial fuel cell applications

In this research, the preparation of low cost proton exchange membranes (PEMs) based on sulfonated poly ether ether ketone (SPEEK) for application in the microbial fuel cells (MFCs) is studied. Sulfonated polystyrene (SPS) and phosphotungstic acid (PWA) were employed to improve the performance of PEM through the creation of more proton pathways. At first, the sulfonation of PEEK and polystyrene were performed through two modified methods to obtain uniform and high degree of sulfonation (DS) of the polymers and then, the PEMs were prepared through the solution casting method. Accordingly, the formation of uniform skin layer was confirmed by the SEM micrographs. Blending the aforementioned additives to the SPEEK polymer solution significantly enhanced the proton conductivity, water uptake and durability of the modified membranes. The proton conductivities of SPEEK/SPS and SPEEK/PWA membranes at additive/SPEEK weight ratio of 0.15 were 45.3% and 26.2% higher than that of the commercial Nafion117 membrane, respectively. Moreover, the degradation times for the abovementioned modified membranes were 140 and 350 min which indicated satisfactory oxidation stability. Besides, the aforementioned membranes exhibited two times more water uptake compared to the neat SPEEK membrane. Finally, SPEEK/SPS and SPEEK/PWA membranes produced 68% and 36% higher maximum power in the MFC, compared to the commercial Nafion117 membrane. Therefore, the fabricated PEMs are potentially suitable alternatives to be used in the fuel cell applications.     

Modeling triplet spike-timing-dependent plasticity using memristive devices

Triplet-based spike-timing-dependent plasticity (TSTDP) is an advanced synaptic plasticity rule that results in improved learning capability compared to the conventional pair-based STDP (PSTDP). The TSTDP rule can reproduce the results of many electrophysiological experiments, where the PSTDP fails. This paper proposes a novel memristive circuit that implements the TSTDP rule. The proposed circuit is designed using three voltage (flux)-driven memristors. Simulation results demonstrate that our memristive circuit induces synaptic weight changes that arise due to the timing differences among pairs and triplets of spikes. The presented memristive design is an initial step toward developing asynchronous TSTDP learning architectures using memristive devices. These architectures may facilitate the implementation of advanced large-scale neuromorphic systems with applications in real-world engineering tasks such as pattern classification.     

Regardless if it is comedy,action, thriller,or biography: A review of urban crime in the 1980s cinema of Chicago

This study investigates the cinematic representation of city crime transactions in Chicago in the 1980s. The narrative nature of cinema provides an imaginative context for interpreting the physical and nonphysical dimensions of urban crimes. From a critical interpretive position, based on Peirce's semiotics, this study uses “urban cinesemiotics” as the method to select image signs, identify their associated Chicagoan objects, and interpret their design-oriented meaning. The theoretical roots of crime prevention through environmental design constitute the basis for the interpretation of movies. A total of 27 crime-related scenes from 9 Chicagoan movies made in the 1980s illustrate that most urban settings suffer from the lack of crime-preventive environmental design. In particular, natural surveillance (eyes on the street), encounter and enclosure, and border vacuums are major environmental factors that affect urban crimes in Chicago. Some crime scenes also depict why environmental design cannot influence individuals' criminal intentions necessarily nor can they solve urban safety single-handedly.     

Evaluation of Thermodynamic Models for Prediction of Sorption Behavior into the Polydimethylsiloxane Membrane in Pervaporation Process

This work focuses on modeling of the sorption step as a main step in the mass transport through the pervaporation process. For this purpose, four thermodynamic models including Flory–Huggins (FH), Universal Quasichemical (UNIQUAC), modified Non-Random Two-Liquid (M-NRTL), and modified Wilson (M-Wilson) were used to predict the equilibrium sorption of ethanol/water mixtures into the polydimethylsiloxane (PDMS) membrane. In the M-Wilson model, the reference state based on pure enthalpy of components was used to determine the residual term. Moreover, the influences of ethanol feed content and temperature on the liquid sorption level and sorption selectivity were studied experimentally and theoretically. The results indicated that the proposed models were successfully able to determine the sorption level of the ethanol aqueous solutions into the PDMS membrane. Moreover, the M-NRTL and M-Wilson models were found to be much more accurate than the FH and UNIQUAC models to determine the volume fraction of the penetrants in the PDMS membrane. It was also observed that the total and ethanol sorptions increased with an enhancement in the ethanol feed concentration, while the membrane sorption selectivity decreased. Moreover, increasing the operating temperature led to higher sorption of both ethanol and water, whereas the sorption selectivity did not show significant changes with temperature.     

Wind resource assessment over Iran using weather station data

This paper investigates the wind energy potential over 42 sites in Iran. Ten years of wind data (1996–2005) were used from weather stations located at these sites. Different criteria were considered, including vertical wind profile, wind power density (WPD), wind frequency distribution, wind sustainability, seasonal variation, turbulence intensity and peak demand matching. Air density and roughness length, which play important role in the calculation of the WPD potential, were derived for each station site. Simple scoring was used to rank the mostly windy sites. It is concluded that Sistan and Bluchistan governorate (Zabol) has the highest potential. Zahedan, Jazireh Kish and Ardebil also have high wind power potential.     

Analysis of Novel Approach to Design of Ultra‐wide Stopband Microstrip Low‐Pass Filter Using Modified U‐Shaped Resonator

A novel microstrip low‐pass filter is presented to achieve an ultra‐wide stopband with 11 harmonic suppression and very sharp skirt characteristics. The filter is composed of a modified U‐shaped resonator (which creates two fully adjustable transmission zeroes), a T‐shaped resonator (which determines a cut‐off frequency), and four radial stubs (which provide a wider stopband). The operating mechanism of the filter is investigated based on a proposed equivalent‐circuit model, and the role of each section of the proposed filter in creating null points is theoretically discussed in detail. The presented filter with 3 dB cut‐off frequency has been fabricated and measured. Results show that a relative stopband bandwidth of 164% (referred to as a 22 dB suppression) is obtained while achieving a high figure‐of‐merit of 15,221.     

The removal of cationic dyes from aqueous solutions by adsorption onto pistachio hull waste

The efficacy of pistachio hull powder (PHP) prepared from agricultural waste was investigated in this study as a novel adsorbent for the elimination of dye molecules from contaminated streams. Removal of methylene blue (MB) as a cationic model dye by PHP from aqueous solution was studied under different experimental conditions. The selected parameters were solution pH (2–10), PHP dosage (0.5–3 g/L), MB concentrations (100–400 mg/L), contact time (1–70), and solution temperature (20–50 °C). The experimental results indicated that the maximum MB removal could be attained at a solution pH of 8. The dosage of PHP was also found to be an important variable influencing the MB removal percentage. The removal efficiency of MB improved from 94.6 to 99.7% at 70 min contact time when the MB concentration was decreased from 300 to 100 mg/L at a pH and PHP dosage of 8 and 1.5 g/L, respectively. The kinetic analysis showed that the pseudo-second-order model had the best fit to the experimental data. The Langmuir equation provided the best fit for the experimental data of the equilibrium adsorption of MB onto PHP at different temperatures. In addition, the maximum adsorption capacity increased from 389 to 602 mg/g when the temperature was increased from 20 to 50 °C. The thermodynamic evaluation of MB adsorption on PHP revealed that the adsorption phenomenon under the selected conditions was a spontaneous physical process. Accordingly, pistachio hull waste was shown to be a very efficient and low-cost adsorbent, and a promising alternative for eliminating dyes from industrial wastewaters.