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971.
Junaid Saleem SK. Safdar Hossain Amir Al-Ahmed Ateequr Rahman Gordon McKay Mohammed M. Hossain 《Journal of Electronic Materials》2018,47(4):2277-2289
In this work, CeO2-modified Pd/CeO2-carbon nanotube (CNT) electrocatalyst for the electro-oxidation of formic acid has been investigated. The support CNT was first modified with different amounts (5–30 wt.%) of CeO2 using a precipitation-deposition method. The electrocatalysts were developed by dispersing Pd on the CeO2-CNT supports using the borohydride reduction method. The synthesized electrocatalysts were analyzed for composition, morphology and electronic structure using x-ray diffraction (XRD), scanning electron microscopy with energy-dispersive x-ray spectroscopy (SEM/EDX), transmission electron microscopy (TEM), x-ray photoelectron spectroscopy (XPS), and thermogravimetric analysis (TGA) techniques. The formation of Pd nanoparticles on the CeO2-CNT support was confirmed using TEM. The activity of Pd/CeO2-CNT and of Pd-CNT samples upon oxidation of formic acid was evaluated by using carbon monoxide stripping voltammetry, cyclic voltammetry, and chronoamperometry. The addition of moderate amounts of cerium oxide (up to 10 wt.%) significantly improved the activity of Pd/CeO2-CNT compared to the unmodified Pd-CNT. Pd/10 wt.% CeO2-CNT showed a current density of 2 A mg?1, which is ten times higher than that of the unmodified Pd-CNT (0.2 A mg?1). Similarly, the power density obtained for Pd/10 wt.% CeO2-CNT in an air-breathing formic acid fuel cell was 6.8 mW/cm2 which is two times higher than Pd-CNT (3.2 mW/cm2), thus exhibiting the promotional effects of CeO2 to Pd/CeO2-CNT. A plausible justification for the improved catalytic performance and stability is provided in the light of the physical characterization results. 相似文献
972.
Self-healing capability offers great designability on mechanical properties of double-network (DN) hydrogel. However, the thermodynamics understanding behind such physicochemical transitions and self-healing behaviors are yet to be explored properly. This study describes a renormalized Flory-Huggins lattice model for DN hydrogels, of which the physicochemical kinetics and dynamic complexity are resulted from stress-induced bond scission and macromolecule rearrangement. Based on the Flory-Huggins lattice model and Gaussian distribution theory, an extended free-energy model was formulated by the steric repulsive free-energy function. Afterwards, the function was used to identify the working mechanisms and thermodynamics in self-healing DN hydrogels with ultra-high mechanical strength. Finally, the effectiveness of model was demonstrated by applying it to predict the mechanical behaviors of DN hydrogels, where the analytical results showed good agreements with experiment data. 相似文献
973.
Multiobjective optimization of microalgae (Chlorella sp.) growth in a photobioreactor using Box‐Behnken design approach 下载免费PDF全文
S. M. Zakir Hossain Abdullah Alnoaimi Shaikh A. Razzak Husny Ezuber Nader Al‐Bastaki Mohammed Safdar Salman Alkaabi Mohammad M. Hossain 《加拿大化工杂志》2018,96(9):1903-1910
974.
975.
In order to predict scratch performance of polymers, the present study focuses on quantitative assessment of various scratch-induced deformation mechanisms based on a set of model amorphous polymers via numerical modeling. A modification of Ree-Eyring theory is used to account for the rate dependent behavior of the model polymers at high strain rates using the experimental data obtained at low strain rates. By incorporating the rate and pressure dependent constitutive and frictional behaviors in the finite element methods (FEM) model, good agreement has been found between FEM simulation and experimental observations. The results suggest that, by including appropriate constitutive relationship and frictional model in the numerical analysis, the scratch behavior of polymers can be quantitatively predicted with reasonable success. Usefulness of the present numerical modeling for designing scratch resistant polymers is discussed. 相似文献
976.
Saeed Uz Zaman Khan Md. Shafayat Hossain Fahim Ur Rahman Rifat Zaman Md. Obaidul Hossen Quazi D. M. Khosru 《International Journal of Numerical Modelling》2015,28(4):389-403
High‐κ gate‐all‐around structure counters the Short Channel Effect (SCEs) mostly providing excellent off‐state performance, whereas high mobility III–V channel ensures better on‐state performance, rendering III–V nanowire GAAFET a potential candidate for replacing the current FinFETs in microchips. In this paper, a 2D simulator for the III–V GAAFET based on self‐consistent solution of Schrodinger–Poisson equation is proposed. Using this simulator, capacitance–voltage profile and threshold voltage are characterized, which reveal that gate dielectric constant (κ) and oxide thickness do not affect threshold voltage significantly at lower channel doping. Moreover, change in alloy composition of InxGa1‐xAs, channel doping, and cross‐sectional area has trivial effects on the inversion capacitance although threshold voltage can be shifted by the former two. Although, channel material also affects the threshold voltage, most sharp change in threshold voltage is observed with change in fin width of the channel (0.005 V/nm for above 10 nm fin width and 0.064 V/nm for sub‐10 nm fin width). Simulation suggests that for lower channel doping below 1023 m−3, fin width variation affects the threshold voltage most. Whereas when the doping is higher than 1023 m−3, both the thickness and dielectric constant of the oxide material have strong effects on threshold voltage (0.05 V/nm oxide thickness and 0.01 V/per unit change in κ). Copyright © 2014 John Wiley & Sons, Ltd. 相似文献
977.
Ekram Hossain Dusit Niyato Dong In Kim 《Wireless Communications and Mobile Computing》2015,15(11):1530-1564
The cognitive radio (CR) paradigm for designing next‐generation wireless communications systems is becoming increasingly popular, and different aspects of it are being implemented in currently available wireless systems. In the last decade, a significant amount of research efforts has been made to solve CR challenges, and several standards related to CR and dynamic spectrum access have been developed. Also, there have been advances in software‐defined radio platforms to implement the CR systems. In this article, we provide a comprehensive survey on the evolution of CR research covering aspects such as spectrum sensing, measurements and statistical modeling of spectrum usage, physical layer aspects such as waveform and modulation design, multiple access, resource allocation and power control, cognitive learning, adaptation and self‐configuration, multihop transmission and routing, and robustness and security in CR networks. Also, state‐of‐the‐art research on the economics of CR networks, CR simulation tools, testbeds and hardware prototypes, CR applications, and CR standardization efforts is summarized. Emerging trends on CR research and open research challenges related to the cost‐effective and large‐scale deployment of CR systems are outlined. Copyright © 2013 John Wiley & Sons, Ltd. 相似文献
978.
Salman Z Chow KH Miller RI Morello A Parolin TJ Hossain MD Keeler TA Levy CD MacFarlane WA Morris GD Saadaoui H Wang D Sessoli R Condorelli GG Kiefl RF 《Nano letters》2007,7(6):1551-1555
The magnetic properties of a monolayer of Mn12 single molecule magnets grafted onto a silicon (Si) substrate have been investigated using depth-controlled beta-detected nuclear magnetic resonance. A low-energy beam of spin-polarized radioactive 8Li was used to probe the local static magnetic field distribution near the Mn12 monolayer in the Si substrate. The resonance line width varies strongly as a function of implantation depth as a result of the magnetic dipolar fields generated by the Mn12 electronic magnetic moments. The temperature dependence of the line width indicates that the magnetic properties of the Mn12 moments in this low-dimensional configuration differ from bulk Mn12. 相似文献
979.
Enhancement of bioseparation and dewaterability of domestic wastewater sludge by fungal treated dewatered sludge 总被引:4,自引:0,他引:4
A promising biological, sustainable, non-hazardous, safe and environmental friendly management and disposal technique of domestic wastewater sludge is global expectation. Fungal entrapped biosolids as a result of prior fungal treated raw wastewater sludge was recycled to evaluate its performance as inoculum for bioseparation/bioconversion of supplemented sludge in view of continuous as well as scale up wastewater sludge treatment. Encouraging results were achieved in bioseparation of suspended solids and in dewaterability/filterability of treated domestic wastewater sludge. Fungal entrapped biosolids offered 98% removal of total suspended solids (TSS) in supplemented sludge treatment at 6-day without nutrient (wheat flour, WF) supply. Consequently, 99% removal of turbidity and 87% removal of chemical oxygen demand (COD) were achieved in supernatant of treated sludge. The lowest value (1.75 x 10(12)m/kg) of specific resistance to filtration (SRF) was observed at 6-day after treatment, which was equivalent to the 70% decrease of SRF. The all results except SRF were not influenced further in treatments accompanied with WF supplementation. The present treatments offered significant (P相似文献