A series of MgO-La 2 O 3 nanocatalysts were prepared via a co-precipitation method and used for biodiesel production from sunflower oil. The results showed that with increasing Mg/La weight percent the catalytic activity increases obviously. Also the results showed that the catalyst with Mg/La=60wt.% (based on weight of La) is an optimal nanocatalyst. The best operational conditions were the CH 3 OH/oil=18/1 at 338 K with mechanical stirring 700 rpm for 5 h. Furthermore, the optimal nanocatalyst showed high catalytic activity for biodiesel production and the biodiesel yield reached 97.7% under the optimal conditions. Furthermore, this nanocatalyst was used for 4 runs in biodiesel production without significant decrease of catalytic performance. Also kinetic and thermodynamic of reaction has been studied in the presence of optimal nanocatalyst. From the kinetic and thermodynamic studies, E a =77.6 kJ.mol-1 , A= 3.5x10 7 lit.mol-1 s-1 , =162 kJ.mol-1 K-1 , =0.54 kJ.mol-1 K-1 were obtained. Characterization of catalysts was carried out by using scanning electron microscopy (SEM), Xray diffraction (XRD), temperature programmed desorption (TPD), Fourier transform-infrared spectroscopy (FT-IR) and N 2 adsorption-desorption measurement methods.

a high fracture strain of at least 10% [10] make MoS 2 and other 2D semiconductors good candidates for applications in flexible electronic devices and circuits. [11] However, several technical challenges need to be overcome before flexible devices based on 2D materials become widely available. Among them, a stable and controllable doping method that is compatible with flexible substrates and low processing temperatures should be developed. Strategies based on exposure to plasma, intercalation, and implantation were only demonstrated on multilayer MoS 2 [12][13][14] which is less interesting for optoelectronic applications due to its indirect bandgap. Substitutional doping with, for example, rhenium or niobium during CVD growth result in doping levels that cannot be modified after growth and are difficult to implement locally and selectively. [15,16] Chemical doping on the other hand, can be easily implemented due to the large surface to volume ratio of 2D materials. [17] Various molecular surface doping methods based on wet chemical treatment have been widely explored, but most of them are not air-stable and are difficult to control. [18][19][20][21] While doping strategies based on functionalizing 2D materials with noble metal nanoparticles offer air stability, they do not result in good uniformity. [22,23] Stable and controllable doping could be achieved using Cs 2 CO 3 thin films by varying the film thickness [24] or phosphorus silicate glass (PSG) substrates through thermal and optical activation; [25] however, brittle Cs 2 CO 3 films and PSG substrates are not suitable for flexible electronics. So far, a practical technique for achieving air-stable and controllable doping of MoS 2 using materials and processes that are compatible with flexible electronics is missing.An effective encapsulation layer with good gas barrier performance is another key enabler for flexible devices based on MoS 2 and other 2D semiconductors. It is well known that the performance of MoS 2 FETs degrades in air due to surface adsorption of O 2 and H 2 O. [26][27][28] Al 2 O 3 , HfO 2 , and other high-κ inorganic dielectrics have been commonly used as encapsulation layers for layered 2D devices. [2,29] However, their brittleness makes them undesirable for applications in flexible electronics, where the encapsulation layer usually experiences the highest strain under bending. Hexagonal boron nitride, a layered insulating material, is a promising candidate for encapsulation of other 2D materials due to the clean and smooth interface free of dangling bonds, but encapsulation is performed using a material transfer process which has so far been restricted to laboratory scale. [30][31][32] Favorable mechanical and electrical properties motivate the use of 2D semiconductors in flexible electronic devices. One of the main challenges here is the absence of a practical doping strategy which should provide air-stable, tunable doping levels in a process with a low thermal budget. Here, it is shown that SU8, an epoxy-based photoresist, can be used ...

High—speed atomic force microscopy has proven to be a valuable tool for the study of biomolecular systems at the nanoscale. Expanding its application to larger biological specimens such as membranes or cells has, however, proven difficult, often requiring fundamental changes in the AFM instrument. Here we show a way to utilize conventional AFM instrumentation with minor alterations to perform high-speed AFM imaging with a large scan range. Using a two—actuator design with adapted control systems, a 130 × 130 × 5 μm scanner with nearly 100 kHz open—loop small-signal Z—bandwidth is implemented. This allows for high-speed imaging of biologically relevant samples as well as high-speed measurements of nanomechanical surface properties. We demonstrate the system performance by real-time imaging of the effect of charged polymer nanoparticles on the integrity of lipid membranes at high imaging speeds and peak force tapping measurements at 32 kHz peak force rate.

The aim of this study was to use the raw pistachio hull powder for the removal of Cd(II) and Pb(II) from aqueous solutions. The kinetic experiments showed that the biosorption of Cd(II) and Pb(II) on the adsorbent is rapid, and maximum biosorption capacities were achieved in 2 h. The time-dependent biosorption of Cd(II) and Pb(II) onto the adsorbent were well described by both the pseudo-first-order and the pseudosecond-order models. The experimental adsorption capacity (qexp) was close to that calculated from these two models. The equilibrium adsorption of Cd(II) and Pb(II) was satisfactorily described by the Sips isotherm. The adsorption isotherms showed that the affinity of Cd(II) and Pb(II) to the adsorbent increased with pH. Based on the estimates obtained by the Visual MINTEQ code, the Pb 2+ and Cd 2+ species were the dominant ones in the solutions at pH ≤ 7.0 and ≤ 8.5, respectively. The Fourier transform-infrared results confirmed the interactions between metals and functional groups present on the surface of pistachio hull. These findings show that the raw pistachio hull powder used in this study exhibited a high adsorption capacity for Cd(II) and Pb(II), and thus it may be useful for the immobilization of these metals from polluted sites. M. Hamidpour et al. 308 infrarroja por transformadas de Fourier confirmaron las interacciones entre los metales y los grupos funcionales presentes en la superficie de la cáscara de pistache. Estos resultados muestran que el polvo de cáscara de pistache sin procesar utilizado en el presente estudio tuvo una alta capacidad de adsorción para Cd(II) y Pb(II), y por consiguiente podría ser de utilidad para remover estos metales de sitios contaminados.