Conductive and antibacterial cellulose nanofibers decorated with copper nanoparticles for potential application in wearable devices

One of the contributions of nanotechnology to our daily life is the preparation of a large variety of polymer-based nanofibers, which could be the basis of future wearable devices. Wearable electronics are a great part of smart textiles research. Herein, we have reported an easy method to fabricate electrically conductive cellulose nanofibers (CNFs). To fabricate CNFs, we first prepared cellulose acetate (CA) nanofibers by using the electrospinning technique and later, the deacetylation process was done to obtain the CNFs. The electroless deposition (ELD) technique was then used to create the conductive nanofibers. Copper (Cu) was used to coat the CNFs because of their high conductivity and low cost. The ELD process parameters including time, temperature, volume, and pH were optimized to obtain a nanofiber with higher conductivity. The optimized condition was temperature: 40 °C, time: 10 min, volume: 600 ml, and pH: 13 to obtain a nanofiber web with 983.5 S/cm conductivity. Cu-coated CNFs were characterized by scanning electron microscope, energy-dispersive X-ray spectroscopy, Fourier-transform infrared spectroscopy, water contact angle, antibacterial activity, tensile, and electrical conductivity. The bending cycle test was performed to quantitatively demonstrate the durability and flexibility of the Cu-coated nanofibers. Cu-coated CNFs exhibited great performance to be used as a conductive layer with antibacterial activity.     

Participatory Water-Food-Energy Nexus Approach for Evaluation and Design of Groundwater Governance

Water Resources Management - Improving the groundwater governance structure can help reduce groundwater decline and improve the state of an aquifer. This study develops an approach to modify...     

Analysis of a new drying chamber for heat pump mint leaves dryer

Drying is an energy intensive and time consuming process, so reducing amount of demanded energy and drying time are important issues for drying technology. The main aim of this paper is to analyze the drying characteristics of mint leaves in a new cylindrical form of drying chamber at low drying air temperature and by emphasizing on energy analysis. The dryer consists of air source heat pump system, air to air heat recovery unit and proportional temperature controller. Experiments were performed at 2, 2.5 and 3 m/s air velocities and at 35 °C cabin inlet air temperature. Mint leaves were dried from 9 g water/g dry matter to 0.1 g water/g dry matter. Designed drying chamber, with three stainless steel cylinders in circular nested form, has a positive effect for drying technology. This system has some advantages such as: drying of product by accessing a uniform air flow and preventing spread of light weight samples like mint leaves over drying system. Calculations based on experimental data show that in the best case, by consuming 3.164 kWh energy in a heat pump with 3.94 coefficients of performance, 4.56 kWh energy had been gained by heat recovery unit. Average 48% of energy was saved by means of heat recovery unit. Effective moisture diffusivity values varied from 3.50E?11 to 5.88E?11 for mint leaves.     

Increasing the adsorption capabilitiy of mordenite and Y zeolites via post‐synthesis chemical/physical treatments in order to remove cationic dyes from polluted water

Different post‐synthesis approaches were used to increase the adsorption abilities of zeolite mordenite and Y in removal of cationic dye molecules as typical dyestuff pollutants. Various methods including acid leaching, alkaline treatment, dealumination with hexafluorosilicate, sonication and combination of them were employed to alter the porous structure of various types of selected zeolites. The dealumination (due to acid leaching), desilication (due to alkaline treatment) and disintegration (due to shear forces generated by ultrasound waves) were responsible for the alteration of pores size and accessibility in mordenite. Acid leaching combined with irradiation of ultrasound was found to be most effective technique in adsorption of rhodamine B as a large dye molecule into mordenite. In the case of zeolite Y, a chemical treatment with ammonium hexafluorosilicate resulted in considerable improvement of adsorption of rhodamine B.     

Performance of modified H-ZSM-5 zeolite for dehydration of methanol to dimethyl ether

The conversion of methanol to dimethyl ether was carried out over various commercial zeolites and modified H-ZSM-5 catalysts to evaluate their catalytic performance. A series of commercially available zeolite samples were used for vapor-phase dehydration of methanol to DME. Catalyst screening tests were performed in a fixed-bed reactor under the same operating conditions (T = 300 °С, P = 16 barg, WHSV = 3.8 h⁻¹). It was found that all the H-form zeolite catalysts in this study were active and selective for DME synthesis. According to the experimental results MDHC-1 catalyst exhibited the highest activity in dehydration of methanol.After finding the most active catalyst, the H-MFI90 zeolite was modified with Na content varying from 0 to 120 mol%, via wet-impregnation method to further improve its selectivity. All of catalysts were characterized by BET, XRD, NH₃-TPD, ICP, TGA, SEM, FT-IR and TPH techniques. It was found that these materials affected activity of MDHC-1 zeolite by changing its acidity. Ultimately, among all the catalysts studied, Na₁₀₀-modified H-MFI90 zeolite exhibited optimum activity, selectivity and stability at methanol dehydration reaction.     

Efficient XML data placement schemes over multiple mobile wireless broadcast channels

The Journal of Supercomputing - Broadcasting is one of the basic ways to access XML data via mobile wireless networks. In these networks, XML data are disseminated over a wireless broadcast channel...     

Reducing the deposition of fat and protein covered particles with low energy surfaces

Deposition behavior of spray dried full cream milk, skim milk and whey particles were observed in a pilot scale dryer. Particle surface dominated with fats exhibit gradual decrease in deposition fluxes when transition from the initial adhesion to the subsequent cohesion mechanism. Whey protein, however, displayed significant differences in the adhesion and cohesion fluxes. Reduction of particle deposition on low energy chamber wall surface is more significant for the hydrophobic whey particles. Further analysis shows that the reduction in droplet–wall contact energy is larger for the more hydrophobic droplet, delineating weaker adhesion interaction. The results suggest that the hydrophobicity of the depositing particles in an important consideration when using lower chamber wall with lower surface energy. This is in addition to the effect of particle rigidity and deposition strength as reported previously.