Study of the variation of catalyst loading in cathode for SPEEK/CSMM membrane in direct methanol fuel cell (DMFC)

Variation of anode catalyst loading for modified sulfonated poly (ether ether ketone) (SPEEK) with charged surface modifying macromolecules (cSMM) membrane was studied, in order to get the higher performance in DMFC. The best optimal anode catalyst loading was 4 mgcm-2 for 30% Pt/Ru based on our previous result for this application. The modified SPEEK/CSMM membrane was characterized to ensure of its better performance in term of water uptake and methanol permeability. In cathode side, the effect of 5% and 10% Pd/C in 2,4 and 6 mgcm-2 of catalyst loading has been investigated with a fuel cell assembly. The preparation method of catalyst ink and membrane electrode assembly (MEA) was based on Dr. Blade method and hot pressing by using catalyzed diffusion media (CDM) method. The air flowrates were varied from 25-1000ml min-1, while 1M methanol concentrations, 1 ml min-1 of methanol flowrate and 60°C operating temperature were kept constant. These parameters were tested on the performance of single cell DMFC with 4 cm2 electrodes.The optimization catalyst loading will enhance the DMFC performance. It was found, the best optimal cathode catalyst loading was 4 mgcm-2 for 10% Pd/C with 4 mgcm-2 for 30% Pt/Ru in anode side for this application

Fabrication of nanocomposite membrane via combined electrospinning and casting technique for direct methanol fuel cell

Emergence of nanotechnology has resulted in the introduction of the electrospinning process in fabricating and characterising the polymer electrolyte membrane from the sulfonated poly (ether ether ketone) (SPEEK) nanocomposite membrane comprised of electrospun Cloisite15A® (e-spun CL) for direct methanol fuel cell (DMFC). Poly (ether ether ketone) polymer is sulfonated up to 63% by sulfuric acid. SPEEK63/e-spun CL nanofibers were fabricated via electrospinning in which SPEEK63 was used as carrier polymer while the SPEEK63/e-spun CL nanocomposite membrane was obtained by the casting method. Characterizations on physical, morphological and thermal properties of SPEEK63/e-spun CL were conducted and compared to the SPEEK membrane fabricated by casting simple mixing 2.5wt.% Cloisite15A® and 5.0wt.% triaminopyrimidine solution (SPEEK63/2.5CL/5.0TAP). Scanning electron microscopy (SEM) showed well electrospun Cloisite15A® with an average diameter nanofiber around 187.4 nm. Moreover, field emission scanning electron microscopy (FESEM) revealed that Cloisite15A® particles at a nanometer range were uniformly distributed and 66% smaller than those in SPEEK63/2.5CL/5.0TAP. Furthermore, x-ray diffraction proved that the dispersion state of Cloisite15A® fell into an intercalated phase. A very small amount of Cloisite15A® (0.05wt.%) in SPEEK63/e-spun CL successfully enhanced the proton conductivity up to 50%, whereas, unfortunately the methanol permeability value was 27 times higher than SPEEK63/2.5CL/5.0TAP. Proton conductivity and methanol permeability of SPEEK63/e-spun CL were 24.49 x 10-3 Scm-1 and 3.74 x 10-7 cms-1, respectively. Even though this study contributed to 95% selectivity lower than SPEEK63/2.5CL/5.0TAP, electrospinning showed a promising technique to further reduce original sized Cloisite15A® particles from mixed size (μm and nm) to nanometer sized. In addition, by fine tuning, the dispersion of Cloisite15A® enhances the SPEEK63/e-spun CL performance in DMFC

Rheological and filtration control performance of water-based drilling muds at different temperatures and salt contaminants using surfactant-assisted novel nanohydroxyapatite

Today, the high-performance rheological and filtration properties of nanosized particles (NPs) in water-based muds (WBMs) are continuously reported. Nevertheless, NP's properties performance at different temperatures and salt environments, specifically the salt-screening process, needs additional knowledge. Hence, this study developed a WBM system using sodium dodecyl sulfate (SDS)-assisted nanohydroxyapatite (Nano-HAp) for different temperatures and salt contaminants. The impacts of the newly-produced Nano-HAp on the density, pH, rheology, and filtration characteristics of WBM at 298 K and 353 K were examined. The effects of salt cations (Ca2+/Na+) on a bentonite-based suspension (BN-WBM) at 298 K and 393 K and SDS-aided Nano-HAp as a salt-tolerant ingredient in drilling muds were also examined. The Herschel-Buckley and Power law models best described SDS-aided Nano-HAp drilling mud's rheology at 298 K and 353 K, respectively. Nano-HAp improved the rheological and filtration capabilities in salt and water solutions at 298 K, 353 K, and 393 K, making it a perfect field additive. 1.0 g of SDS-aided Nano-HAp is recommended, and it is thermally very stable, according to the thermal gravimetric analysis findings. It increased the viscosity performance by 78.6% at 298 K and by 79.2% at 353 K, provided desirable shear stress between 1.0 and 1000 s−1 shear rates, and decreased the fluid loss by 31.8% (≤ 8 mL) at 298 K and 25% (≤ 11 mL) at 353 K. In BN-WBM, it decreased the viscosity of the BN-salt solution from a 35-fold increase to less than a 5-fold increase and made the BN-based suspension less salt-reliant. It operated by attaching to the BN platelets' positive edge and negative face surfaces, shielding Ca2+/Na+ cations from the BN's ion-susceptible regions to decrease the viscosity and filtration of the BN-based suspension. This study demonstrates the possible use of Nano-HAp particles as effective filtration and rheological control additives in WBMs. It further demonstrates that Nano-HAp was appropriate for enhancing the drilling performance of BN-WBMs while increasing their resistance to salt cation contamination

Pitch scale harmonic filter

Pitch is defined as the property of sound that varies with variation in the frequency of vibration. In speech processing aspect, pitch is defined as the fundamental frequency (oscillation frequency) of the glottal oscillation (vibration of the vocal folds). Pitch information is one of speech acoustical features that not often taken into consideration while doing speech recognition. In this research, pitch is taken into consideration then it is optimized and was used as another feature into NN along with DTW-FF feature. Pitch contains spectral information of a particular speech; it is the feature that was used to determine the fundamental frequency, F0 of a speech at a particular time

Performance evaluation and fouling prevention of polymeric nanofiltration membrane for treating textile dyeing wastewater

Textile industry is one of the oldest and heaviest polluter in the world. Nowadays, approximately half of the available water is being used for domestic purposes, and the other half is consumed by the industrial and agricultural activities. The increasing world population results in the need for more production of clothes and hence more water consumption is required for the industrial processes. In general, substantial amounts of waters, mineral salts and reactive dyes are used on an average for every kilogram of fabric produced, causing a large amount of wastewater generated from the industrial daily operation. All the effluent discharged from industry present the same problem in terms of not environmentally friendly. Thus, it is paramount important to have a proper treatment system before it is discharged into environment in order to minimize the water pollution. It is known that the loss of dyes to the effluent can interfere with the transmission of light in receiving waters, interrupting photosynthesis process and aquatic life. Moreover, the effluent which generally has a dark reddishbrown color is aesthetically unpleasing when discharged to water

The development of adsorbent based natural gas storage for vehicle application

Storage of natural gas by adsorption has a potential to replace Compressed Natural Gas (CNG) in mobile storage applications, such as in vehicles. Storage by adsorption at moderate pressure of 500 psig could be expected to reduce the problem of bulky high-pressure CNG storage within a confined space used in vehicle. In adsorptive storage, the amount of gas stored at lower pressure increases when a large portion of gas adsorbs on the adsorbent. However, its capacity and performance depend on adsorbent types and properties. This study is focused on the storage capacity and delivery performance of Adsorptive Natural Gas (ANG) storage employing different types of commercial adsorbents which were carried out by performing experimental work on an ANG storage system. Methane adsorptive storage was done in a 0.5-liter adsorbent-filled gas vessel under isothermal and dynamic conditions. The ANG vessel was charged with methane up to 500 psig at different rates of filling and was discharged under dynamic condition at a varied rate of discharge. The results show that the storage capacity obtained under isothermal condition is higher than under dynamic condition due to continuous temperature rise experienced during dynamic charging. Higher storage capacities were obtained for adsorbent with larger surface area and micropore volume but smaller interparticle void. Adsorbent that has high heat capacity and low heat of methane adsorption yields lesser temperature rise during adsorption and lesser temperature fall during desorption. Consequently, these characteristics lead to a better storage and delivery capacities. At faster charging rate, lower storage capacity was obtained and faster discharging rate caused inefficient gas delivery. Under cyclic operation, adsorbents performances deteriorate when adsorbent structure is gradually damaged under high-pressure operation. Among the adsorbents tested, palm shell activated carbon shows the highest storage and delivery capacity which are 87.4 V/V and 75.8 V/V respectively

Carbon nanotubes based mixed matrix membrane for gas separation

Mixed matrix membranes (MMM) combine useful molecular sieving properties of inorganic fillers with the desirable mechanical and processing properties of polymers. The current trend in polymeric membranes is the incorporation of filler-like nanoparticles to improve the separation performance. Most MMM have shown higher gas permeabilities and improved gas selectivities compared to the corresponding pure polymer membranes. Carbon nanotubes based mixed matrix membrane was prepared by the solution casting method in which the functionalized multiwalled carbon nanotubes (f-MWNTs) were embedded into the polyimide membrane and the resulting membranes were characterized. The effect of nominal MWNTs content between 0.5 and 1.0 wt% on the gas separation properties were looked into. The as-prepared membranes were characterized for their morphology using field emission scanning electron microscopy (FESEM) and Transmission Electron Microscopy (TEM). The morphologies of the MMM also indicated that at 0.7 % loading of f-MWNTs, the structures of the MMM showed uniform finger-like structures which have facilitated the fast gas transport through the polymer matrix. It may also be concluded that addition of open ended and shortened MWNTs to the polymer matrix can improve its permeability by increasing diffusivity through the MWNTs smooth cavity