Synthesis of nickel nanowires (Ni-NWs) as high ferromagnetic material by electrodeposition technique.

Metallic nanowires (NWs) and their different compounds display incredible prospects for their use in various applications including media storage, sensor and solar cell devices along with the biological drug delivery systems. In this research work, the metallic NWs like nickel nanowires (Ni-NWs) are synthesized successfully by employing electrodeposition process. Anodic aluminum oxide (AAO) templates are employed as a platform with copper metal coating which acts as an active cathode. The synthesized Ni-NWs are examined through various characterization techniques including X-ray diffraction (XRD), scanning electron microscope (SEM) and vibrating sample magnetometer (VSM) to study the crystal structure, surface morphology and magnetic properties, respectively. The XRD analysis shows the development of various diffraction planes like Ni (111), Ni (200), Ni (220) which confirms the formation of polycrystalline nickel NWs. The SEM analysis reveals that the range of diameter and length of nickel NWs are found to be ∼160 to 200 and ∼4 to 11 micron respectively showing high aspect ratio (ranged from ∼200 to 300). The ferromagnetic behavior of Ni-NWs is confirmed by the hysteresis loop carried out for parallel and perpendicular configurations having Hc = 100 and 206 Oe, respectively. The obtained results suggest that the synthesized Ni- NWs may be used for high-density media storage devices.

Diffusion coefficients of electrorheological complex (dusty) plasmas.

Equilibrium molecular dynamics (EMD) simulations have been executed to investigate the parallel (D║) and perpendicular (D┴) diffusion coefficients for three-dimensional (3D) strongly coupled (SC) electrorheological complex (dusty) plasmas (ERCPs). The effects of uniaxial (z-axis) AC electric field (MT) on dust grains have been investigated along with various combinations of plasma parameters (Γ, κ). The new outcomes obtained by mean squared displacement of Einstein relation show diffusion coefficients for low-intermediate to high plasma couplings (Γ) for varying MT. The D║ and D┴ at MT = 0.01 agree well with earlier available data obtained from the Green-Kubo and Einstein relation for 3D SC-Yukawa systems. The simulation data show that D║ increased with an increase in moderate MT strength and that D┴ decreased for the intermediate to large MT strength. Both (D║ and D┴) remained nearly constant for low MT values. The investigations show that the current EMD scheme is more efficient for nonideal gas-like, liquid-like, and solid-like states of SC-ERCPs. It has been demonstrated that present simulation outcomes extended the MT range up to 0.01 ≤ MT ≤ 10 to understand the diffusive and rheological behaviors of dusty plasma systems.

Experimental Measurements and Thermodynamic Optimization of the NaCl+RbCl Phase Diagram.

In this study, the phase diagram of the NaCl+RbCl binary system was measured using differential scanning calorimetry, and the measured molar percentages of the binary mixture RbCl ranged from 12 to 97 mol%, updating and extending the experimental data for this binary system. The liquid phase of this system was thermodynamically modeled using a modified quasichemical model, and a computer optimization program for evaluation of the experimental data on phase equilibria and other thermodynamic data was developed based on this model. All thermodynamic models of the NaCl+RbCl binary system were constructed; calculations of the phase diagram, enthalpy of mixing, and activity coefficient of NaCl of the NaCl+RbCl binary system were completed using the obtained model parameters; and the calculated eutectic point positions were xRbCl = 0.567 and 550.2 °C. The calculated results were able to reproduce the various types of experimental data well, and the thermodynamic self-consistency between different types of experimental data was demonstrated.

Development status and some considerations on Energy Internet construction in Beijing-Tianjin-Hebei region.

The coordinated development of the Beijing-Tianjin-Hebei region has become China's national strategy with great and far-reaching significance. The construction of Energy Internet is an important measure to strengthen the coordination of green energy development in Beijing-Tianjin-Hebei region and promote the development of renewable energy. In this paper, based on the development status of renewable energy in the Beijing-Tianjin-Hebei region, the problems and challenges existing in the renewable energy development in the Beijing-Tianjin-Hebei region and related considerations for their solution are reviewed and discussed. Energy Internet has also become a booster for the rapid development of clean and renewable energy. The policies on the Energy Internet Construction issued by Beijing, Tianjin, and Hebei during the 13th Five-Year Plan Period (2016-2020) and at the beginning of the 14th Five-Year Plan Period (2021-2025) are summarized. The focuses of all these policy documents are analyzed. The development status of seven Energy Internet demonstration projects in Beijing-Tianjin-Hebei region is reviewed. On this basis, some considerations on Energy Internet construction in the Beijing-Tianjin-Hebei region are analyzed and proposed.

Dynamic motions and architectural changes in DNA supramolecular aggregates visualized via transmission electron microscopy without liquid cells.

In the last decade, breakthroughs in liquid-phase transmission electron microscopy (TEM) have enabled in situ visualization of the motion dynamics of nanostructures in liquid media with unprecedented detail. However, it remains a significant challenge to perform liquid-phase TEM due to the intricate preparation procedure of liquid cells to keep liquid from evaporating under ultrahigh vacuum conditions in TEM columns. In the present study, the nonvolatility and remarkable solvation property of ionic liquids (ILs) is exploited to image the dynamic processes of DNA supramolecular aggregates and Au nanoparticle (NP) aggregates encompassing Brownian motions, interactions among individual nanoobjects and changes in architecture at nanometer resolution. Significant differences in motion behaviors are observed between DNA supramolecular aggregates and Au NP aggregates. Moreover, the temperature and dose dependence of dynamic motions are also investigated. The findings provide insights into the dynamics of DNA supramolecular aggregates and Au NP aggregates in ILs and present an easily accessible approach for probing the dynamic processes of biomacromolecular and other soft matter aggregates with various kinds of ILs at the nanoscale level.

Isothermal titration calorimetry in a 3D-printed microdevice.

Isothermal titration calorimetry (ITC) can benefit from operating in miniaturized devices as they enable quantitative, low-cost measurements with reduced analysis time and reagents consumption. However, most of the existing devices that offer ITC capabilities either do not yet allow proper control of reaction conditions or are limited by issues such as evaporation or surface adsorption caused inaccurate solution concentration information and unintended changes in biomolecular properties because of aggregation. In this paper, we present a microdevice that combines 3D-printed microfluidic structures with a polymer-based MEMS thermoelectric sensor to enable quantitative ITC measurements of biomolecular interactions. Benefitting from the geometric flexibility of 3D-printing, the microfluidic design features calorimetric chambers in a differential cantilever configuration that improves the thermal insulation and reduces the thermal mass of the implementing device. Also, 3D-printing microfluidic structures use non-permeable materials to avoid potential adsorption. Finally, the robustness of the polymeric MEMS sensor chip allows the device to be assembled reversibly and leak-free, and hence reusable. We demonstrate the utility of the device by quantitative ITC characterization of a biomolecular binding system, ribonuclease A (RNase A) bind with cytidine 2'-monophosphate (2'CMP) down to a practically useful sample concentration of 0.2 mM. The thermodynamic parameters of the binding system, including the stoichiometry, equilibrium binding constant, and enthalpy change are obtained and found to agree with values previously reported in the literature.

General Model Based on Artificial Neural Networks for Estimating the Viscosities of Oxygenated Fuels.

Oxygenated fuel is a promising alternative fuel for engines because of the advantage of low emission. In this work, a general model based on back-propagation neural networks was developed for estimating the viscosities of different kinds of oxygenated fuels including esters, alcohols, and ethers, whose input variables are pressure, temperature, critical pressure, critical temperature, molar mass, and acentric factor. The viscosity data of 31 oxygenated fuels (1574 points) at temperatures ranging from 243.15 to 413.15 K and at pressures ranging from 0.1 to 200 MPa were collected to train and test the back-propagation neural network model. The comparison result shows that the predictions of the proposed back-propagation neural network model agree well with the experimental viscosity data of all studied oxygenated fuels using the general parameters (weight and bias). The average absolute relative deviations for training data, validation data, and testing data are 1.19%, 1.27%, and 1.30%, respectively.

Unusual Transformation of Polymer Coils in a Mixed Solvent Close to the Critical Point.

We have discovered unusual behavior of polymer coils in a binary solvent (nitroethane+isooctane) near the critical temperature of demixing. The exceptionally close refractive indices of the solvent components make the critical opalescence relatively weak, thus enabling us to simultaneously observe the Brownian motion of the polymer coils and the diverging correlation length of the critical fluctuations. The polymer coils exhibit a collapse-reswelling-expansion-reshrinking transition upon approaching the critical temperature. While the first stage (collapse) can be explained by the theory of Brochard and de Gennes, the subsequent expansion-reshrinking transition is a new unexpected phenomenon that has not been observed so far. We believe that this effect is generic and attribute it to microphase separation of the solvent inside the polymer coil.

Mesoscopic Diffusion of Poly(ethylene oxide) in Pure and Mixed Solvents.

We present results from an experimental dynamic light-scattering study of poly(ethylene oxide) (PEO) in both a pure solvent (water) and a mixed solvent (tert-butanol + water). The concentration dependence of the diffusive relaxation of the PEO molecules is found to be typical of polymers in a good solvent. However, the mesoscopic diffusive behavior of PEO in the mixed solvent is very different, indicating an initial collapse and subsequent reswelling of PEO caused by co-nonsolvency. Furthermore, in the solutions of PEO with very large molecular weights, we found additional hydrodynamic modes indicating the presence of PEO clusters and aggregates similar to those found by some other investigators.

Mutual diffusion governed by kinetics and thermodynamics in the partially miscible mixture methanol + cyclohexane.

To gain an understanding of the transport and thermodynamic behavior of the highly non-ideal mixture methanol + cyclohexane, three complementary approaches, i.e. experiment, molecular simulation and predictive equations, are employed. The temperature and composition dependence of different diffusion coefficients is studied around the miscibility gap at ambient pressure. On the one hand Fick diffusion coefficients are measured experimentally by interferometric probing and on the other hand Maxwell-Stefan diffusion coefficients and intradiffusion coefficients are sampled by equilibrium molecular dynamics simulation at five temperatures below the upper critical temperature of ∼319 K. The spinodal curve is determined from extrapolation of the experimental Fick diffusion coefficient data and compared to predictions from excess Gibbs energy models. It is found that these models are not capable to correctly describe the activity coefficients over the whole composition range of the studied mixture. Thus, different parameter sets for a modified Wilson model are used for calculations of the thermodynamic factor, which is needed to transform Maxwell-Stefan into Fick diffusion coefficients and vice versa. Further, predictive equations for the Maxwell-Stefan diffusion coefficient, which are based on intradiffusion coefficients, are compared to simulation results. Using different approaches provides a clearer understanding of the relations between kinetic and thermodynamic properties contributing to the diffusion behavior of partially miscible mixtures.

Study of the measurement for the diffusion coefficient by digital holographic interferometry.

In the measurement of the diffusion coefficient by digital holographic interferometry, the conformity between the experiment and the ideal physical model is lacking analysis. Two data processing methods are put forward to overcome this problem. By these methods, it is found that there is obvious asymmetry in the experiment and the asymmetry is becoming smaller with time. Besides, the initial time for diffusion cannot be treated as a constant throughout the whole experiment. This means that there is a difference between the experiment and the physical model. With these methods, the diffusion coefficient of KCl in water at 0.33 mol/L and 25°C is measured. When the asymmetry is ignored, the result is 1.839×10(-9) m2/s, which is in good agreement with the data in the literature. Because the asymmetry is becoming smaller with time, the experimental data in the latter time period conforms to the ideal physical model. With this idea, a more accurate diffusion coefficient is 2.003×10(-9) m2/s, which is about 10% larger than the data in the literature.

High solubilities of small hydrocarbons in trihexyl tetradecylphosphonium bis(2,4,4-trimethylpentyl) phosphinate.

Experimental solubilities are reported for methane, ethane, ethylene, propane, and propylene in trihexyl tetradecylphosphonium bis(2,4,4-trimethylpentyl) phosphinate [P(14)666][TMPP] from 313 to 353 K up to 6.7 MPa. A literature review on solubilities of small hydrocarbons in ionic liquids shows that solubilities in [P(14)666][TMPP] are appreciably larger than those in other ionic liquids. Contrary to solubilities in ionic liquids studied earlier, solubilities of paraffins (ethane and propane) in [P(14)666][TMPP] are larger than those of the corresponding olefins (ethylene and propylene). Because, at fixed temperature, the vapor pressure of an olefin is larger than that of the corresponding paraffin, the relative volatility of the olefin exceeds that of the corresponding paraffin, contrary to the relative volatility observed in conventional extractive distillation with polar solvents where the volatility of the paraffin exceeds that of the corresponding olefin.