Effect of Interface Layer Capacitance on Polydimethylsiloxane in Electrowetting-on-Dielectric Actuation

Electrowetting is an effective way to manipulate small volume of liquid in microfluidic applications. It has been sophisticatedly used in the fields of Lab-on-a-Chip (LoC) devices, optics, biomedical applications, and electronic paper (e-paper). Generally, Young-Lippmann (Y-L) equation is used to relate the mechanical and electrical force involved in electrowetting-on-dielectric (EWOD) based actuation. And the general trend is to neglect the effect of double layer capacitance formed at the metal-liquid interface considering the Debye-length to be in the order of nanometer. But, at electrode-electrolyte-insulator interface, the effect of interface layer capacitance becomes significant and often leads to the mismatch between the experimental observation and theoretical result. In this work, the surface behaviour of polydimethylsiloxane (PDMS) for EWOD application is studied experimentally and a term “k” has been introduced in the Y-L equation to match the theoretical and experimental result. Effect of interface layer capacitance has been observed in contact angle versus applied voltage experiment with different pH buffer solution. The introduction of “k” term takes care of the interface layer capacitance which can not be neglected and plays a vital role when the applied electric potential is high.

Effect of Molecular Rotational Degrees of Freedom on Mechanical and Thermodynamic Properties of Solid Methane at Temperatures above 50 K

The paper presents an analysis of extensive data set of mechanical, structural, thermophysical, and spectral properties of solid methane in the temperature interval 0.5 · Ttr–Ttr (Ttr is the triple point temperature) under equilibrium vapor pressure. It is shown that the anomalies of the studied properties (or lack of reliable data) at temperatures 60–70 K have been observed in the body of the reviewed papers. We proposed that the observed anomalies are due to a transition between classical and quantum regimes of collective rotational degrees of freedom of methane molecules in this temperature interval.

Gaussian Energy Broadening Function of an HPGe Detector in the Range of 40 keV to 1.46 MeV

High-purity germanium (HPGe) detectors are widely used in nuclear spectroscopy (e.g., neutron activation analysis) due to their high resolution. Resolution function of a GMX series coaxial detector system (model number GMX40P4-83) in the range of 40 keV to 1.46 MeV has been measured using standard γ-ray sources. The energy response function also was calculated using Monte Carlo simulation through the precise modeling of the detector structure. The simulated energy response function was verified with the measured energy response function obtained using calibration sources. A new approach was used and the agreement between both results has been improved.

Electrical Switching in Thin Film Structures Based on Molybdenum Oxides

We report on the experimental study of electrical instabilities in thin film structures on the basis of molybdenum oxides. Thin films of molybdenum oxide are obtained by thermal vacuum evaporation and anodic oxidation. The results of X-ray structural analysis, investigation of optical and electrical properties, are presented. It is shown that the initial vacuum-deposited oxide represents amorphous MoO3. In the MOM (metal-oxide-metal) structures with Mo oxide films obtained by the two methods, the effect of electrical switching with an S-shaped current-voltage characteristic is found. We put forward a hypothesis according to which the switching mechanism is associated with the development of electrical instability caused by the insulator-to-metal transition in Mo8O23. The switching channel, comprising this lower valence oxide, emerges in the initial film during the process of electrical forming of the MOM structure. The obtained results indicate the possibility of application of these structures in oxide micro- and nanoelectronics as electronic switches and other electronic devices.

Thickness and Interface-Dependent Structural, Magnetic, and Transport Properties of Cu/Co Thin Film and Multilayer Structures

Structural, magnetic, and transport properties of electron beam evaporated Co/Cu thin films and multilayer structures (MLS) having different layer thicknesses have been characterized utilizing X-ray diffraction (XRD), magnetooptical Kerr effect (MOKE), and resistivity techniques. The structural studies show distinctive crystal structures for different sublayer thicknesses. The Co (300 Å) single layer film is amorphous, while Cu (300 Å) film is nanocrystalline in nature. The average particle size is found to decrease as the number of interface increases. The corresponding magnetic and resistivity measurements show an increase in saturation field and resistivity as a result of an enhanced anisotropy. However, coercivity decreases with a reduction in average particle size. The results conclude that these properties are greatly influenced by various microstructural parameters such as layer thickness, number of bilayers, and the quality of interfaces molded under different growth conditions.

Approach to the Highest HXR Yield in Plasma Focus Device Using Adaptive Neurofuzzy Inference System to Optimize Anode Configuration

Adaptive neurofuzzy inference system (ANFIS) is investigated to optimize the configuration of anode shape in plasma focus devices to achieve the highest X-ray yield. Variables of discharge voltage, filling gas pressure, and angles of anode slopes (Φ1 and Φ2) are chosen as input parameters, while the output is designated to be the radiated hard X-ray intensity. The trained ANFIS has achieved good agreement with the experimental results and has mean relative error percentages (MRE%) 1.12% and 2.18% for training and testing data, respectively. The study demonstrates that adaptive neurofuzzy inference system is useful, reliable, and low-cost way to interpret the highest X-ray yield and corresponding anode configuration in plasma focus devices.

Thermal Decomposition Study of Ferrocene [(C5H5)2Fe]

A single-step thermal decomposition of ferrocene [(C5H5)2Fe] using nonisothermal thermogravimetry (TG) has been studied using single- as well as multiple-heating rate programs. Both mechanistic and nonmechanistic methods have been used to analyze the TG data to estimate the kinetic parameters for the solid state reaction. Two different isoconversional methods (improved iterative method and model-free method) have been employed to analyze the TG results to find out whether the activation energy of the reaction depends on the extent of decomposition and to predict the most probable reaction mechanism of thermal decomposition as well. A comparison of the activation energy values for the single-step thermal reaction of ferrocene estimated by different methods has been made in this work. An appraisal on the applicability of single-heating rate data for the analysis of single-step thermal decompositions over the recommendations by the International Confederation for Thermal Analysis and Calorimetry (ICTAC) is made to look beyond the choice.