Phase-Matched Electro-Optic Light Modulator

Proposed is a new type optical switch, which consists of an optical divider and a parallel optical shutter. First, optical divider is made of grating designed well, which divides an input beam into three beams. The three beams enter a parallel optical shutter, which consists of PLZT 9/65/35 ceramic plate and three pairs of interdigital electrodes on the plate. Applying about 200 volts to one of three pairs of electrodes, the optical switch turns on and therefore the corresponding beam can pass through the shutter, resulting in working as an optical switch.

Sugar solutions such as sucrose, glucose and fructose are often used in osmotic dehydration processes. Thus, the experimental determination of their thermophysical properties is a must for designing purposes. Density, specific heat and thermal conductivity were determined in a wide range of solute concentration (10–60 °Brix) and temperature (273.15–358.15 K). Empirical equations were considered to fit the experimental data and to evaluate the data behavior. An assessment based on the Prandtl number was considered to correlate thermal and rheological data. Higher density and lower specific heat and thermal conductivity values were observed when temperature decreased and solute concentration increased. Prandtl number behaved similarly as density, indicating that momentum transfer is favored in comparison with heat transfer in more concentrated solutions at lower temperatures. A versatile polynomial model concerning the significant variables could predict the experimental values for all solutions with good accuracy (R2 > .9863 and MRE < 1.20%). Reported data and equations showed to be essential for engineering aspects and transport phenomena analysis.Practical ApplicationsSucrose, glucose and fructose solutions are commonly used in osmotic dehydration processes to promote solute incorporation, increasing shelf‐life and quality of food products. The availability of thermophysical properties in a wide range of solute concentration and temperature covers the most of conventional and nonconventional conditions for designing osmotic dehydration and many other food processes. Among the unit operations, it could be found pumping, mixing/stirring, pasteurization, sterilization, evaporation and so on. These data are useful to understand how properties change when the conditions are altered during the processes. They also provide important information about momentum and heat transfer through the fluid. By analyzing dimensionless parameters, as Prandtl number, one phenomenon or other can be favored under specific conditions. The presence of accurate mathematical models results in greater agility and reliability in the execution of processes, especially for those operating in wide ranges of temperature and solute concentration.

In the present work we apply the cBΩ thermodynamic model to study the diffusion of Si in stishovite crystal at high pressure and in a wide temperature range. According to this model, the point defect activation Gibbs free energy is expressed as a function of the bulk properties of the material, i.e., gact = cBΩ, where B is the isothermal bulk modulus, Ω is the mean atomic volume, and c is a dimensionless constant. In this way, other important point defect parameters, such as the activation volume vact, the activation entropy sact, and the activation enthalpy hact may be estimated if the thermoelastic properties of the material are known over a wide temperature and pressure range. Our calculations are based on previously reported self-diffusion coefficients in stishovite single crystals measured at 14 GPa and at temperatures from 1400 to 1800 °C, in the [110] and [001] directions, by Shatskiy et al. (Am. Mineral. 2010, 95, 135–43). Furthermore, the EOS of stishovite, proposed by Wang et al. (J. Geophys. Res. 2012, 117, B06209) has been used for the accurate implementation of the cBΩ model. Our results suggest that the aforementioned point defect parameters exhibit considerable temperature dependence over the studied temperature range (1000–2000 °C). The estimated activation volumes (4.4–5.3 cm3/mol, in the range of 1400–1800 °C) are in agreement with reported experimental results. Our study confirms the potential of the cBΩ model for the theoretical investigation of diffusion processes in minerals, in order to overcome the experimental difficulties and the lack of experimental diffusion data in mantle conditions.

Separation is a crucial step in the analysis of living microparticles. In particular, the selective microseparation of phytoplankton by size and shape remains an open problem, even though these criteria are essential for their gender and/or species identification. However, microseparation devices necessitate physical membranes which complicate their fabrication, reduce the sample flow rate and can cause unwanted particle clogging. Recent advances in microfabrication such as High Precision Capillary Printing allow to rapidly build electrode patterns over wide areas. In this study, we introduce a new concept of membrane-less dielectrophoretic (DEP) microseparation suitable for large scale microfabrication processes. The proposed design involves two pairs of interdigitated electrodes at the top and the bottom of a microfluidic channel. We use finite-element calculations to analyse how the DEP force field throughout the channel, as well as the resulting trajectories of particles depend on the geometry of the system, on the physical properties of the particles and suspending medium and on the imposed voltage and flow rates. We numerically show that in the negative DEP regime, particles are focused in the channel mid-planes and that virtual pillars array leads either to their trapping at specific stagnation points, or to their focusing along specific lines, depending on their DEP mobility. Simulations allow to understand how particles can be captured and to quantify the particle separation conditions by introducing a critical DEP mobility. We further illustrate the principle of membrane-less DEP microseparation using the proposed setup, by considering the separation of a binary mixture of polystyrene particles with different diameters, and validate it experimentally.

The reaction between H and benzene is a prototype for reactions of radicals with aromatic hydrocarbons. Here we report calculations of the reaction rate constants and the branching ratios of the two channels of the reaction (H addition and H abstraction) over a wide temperature and pressure range. Our calculations, obtained with an accurate potential energy surface, are based on variational transition-state theory for the high-pressure limit of the addition reaction and for the abstraction reaction and on system-specific quantum Rice-Ramsperger-Kassel theory calibrated by variational transition-state theory for pressure effects on the addition reaction. The latter is a very convenient way to include variational effects, corner-cutting tunneling, and anharmonicity in falloff calculations. Our results are in very good agreement with the limited experimental data and show the importance of including pressure effects in the temperature interval where the mechanism changes from addition to abstraction. We found a negative temperature effect of the total reaction rate constants at 1 atm pressure in the temperature region where experimental data are missing and accurate theoretical data were previously missing as well. We also calculated the H + C6H6/C6D6 and D + C6H6/C6D6 kinetic isotope effects, and we compared our H + C6H6 results to previous theoretical data for H + toluene. We report a very novel nonmonotonic dependence of the kinetic isotope effect on temperature. A particularly striking effect is the prediction of a negative temperature dependence of the total rate constant over 300-500 K wide temperature ranges, depending on the pressure but generally in the range from 600 to 1700 K, which includes the temperature range of ignition in gasoline engines, which is important because aromatics are important components of common fuels.

Prediction of thermal expansion properties of carbon nanotubes using molecular dynamics simulations

The strong and specific noncovalent interaction between avidin and biotin is widely exploited in different types of enzyme-linked immunosorbent assay kits, labeled immunosensors, and polymer-based sensing devices for the detection of different biomarkers specific to different diseases such as cancer and influenza. Here, we employed the avidin–biotin technology in a novel gold nanoparticle-decorated graphene field-effect transistor (AuNP-GFET) and demonstrated the specific detection of the biotinylated macromolecules such as biotinylated proteins and nucleotides in the sub-picomolar (pM) range. The AuNP-GFET was constructed by fabricating six pairs of interdigital electrodes on graphene transferred on a SiO2/Si substrate. The sensing performance of AuNP-GFET was characterized by the real-time two-terminal electrical current measurement upon injection of the analyte solution into a silicone pool preattached onto the electrodes. Avidin, a tetrameric biotin-binding protein with strong affinity and specificity, immobilized on AuNP-decorated single-layer graphene, was used as the sensing platform and transduced the electrical signal upon binding to the analyte macromolecules. The sensing capability of the AuNP-GFET was tested with the biotinylated protein A. Sensitivity of the present biosensor was estimated to be ∼0.4 pM. The specificity and applicability of the biosensor were confirmed using both synthetic and real samples. Because the biotin label can retain its binding capability to avidin with strong affinity and specificity even after conjugating with varieties of proteins and nucleotides, the present AuNP-GFET biosensor is expected to promote the research in developing different biosensors.

Dielectric measurement and image analysis are used to evaluate the hydrophobic condition of silicone rubber surface. Hydrophobicity of silicone rubber surface was studied by using image data analysis of sprayed water droplets on the sample surface. Hydrophobicity class, HC from 1 to 7, is evaluated by the analyzed image data indices. The water droplets on the sample surface are digitized and the image indices such as size and shape factor of the droplets were evaluated. After this evaluation, 3D mapping technique is used to evaluate the HC value. The hydrophobic condition of the sample surface was also determined by measuring dielectric property of silicone rubber using a pair of inter-digital electrodes. The dielectric properties were detected by using unbalanced operation of current comparator type capacitance bridge. The changes in dielectric loss current and the capacitive current by the change in hydrophobic condition were measured for every one cycle of AC applied field. Comparing of these results can define the degradation of hydrophobicity of polymer insulator more accurately.

Multi-adaptability supercapacitor electrolyte based on Na-MMT/PDADMAC and application in wide temperature range

The ignition delay time (IDT) characteristics of new ternary and quaternary blended C1 – C3 gaseous hydrocarbons, including methane/ethane/ethylene and methane/ethane/ethylene/propane, are studied over a wide range of mixture composition, temperature (∼800 – 2000 K), pressure (∼1 – 135 bar), equivalence ratio (∼0.5 – 2.0), and dilution (∼75 – 90%) using both experimental data and kinetic modeling tools. In this regard, all of the experimental tests were designed using the Taguchi approach (L9) to fulfill the experimental matrix required to generate a comprehensive set necessary to validate a detailed chemical kinetic model. High- and low-temperature IDTs were recorded using low/high-pressure shock tubes (L/HPST) and rapid compression machines (RCM), respectively. The model predictions using NUIGMech1.2 are evaluated versus all of the newly recorded experimental data. Moreover, the individual effects on IDT predictions of the parameters studied, including mixture composition and pressure, are investigated over the temperature range. The results show that NUIGMech1.2 can reasonably reproduce the experimental IDTs over the wide range of the conditions studied. The constant-volume simulations using the chemical kinetic mechanism reveal the synergistic/antagonistic effect of blending on IDTs over the studied temperature range so that IDTs in certain temperature ranges are very sensitive to even small changes in mixture composition.

n+InAs(Si) epitaxial thin films heavily doped by silicon and Hall effect magnetic field sensors based on this structures have been fabricated and studied. We have demonstrated the successful formation of highly doped InAs thin films (∼100 nm) with the different intermediate layer arrangement and appropriate electron mobility values. Hall sensors performance parameters have been measured in wide temperature range. Obtained sensitivity varied from 1 to 40 Ω/T, while the best linearity and lower temperature coefficient have been found in the higher doped samples with lower electron mobility. We attribute this to the electron system degeneracy and decreased phonon contribution to electron mobility and resistance.

Ab initio calculations of the total dielectronic recombination (DR) rate coefficient of Ni-like barium ( ) and tungsten ( ) in the ground state have been performed using the HULLAC atomic code package. Resonant and nonresonant stabilizing radiative transitions are included. Collisional transitions following electron capture are neglected. The present level-by-level calculations include the DR contributions of all of the levels (over 17000) in the Cu-like inner-shell excited configurations 3d 9 4ln'l' ( ), 3p 5 3d 10 4ln'l' ( ), and 3s3p 6 3d 10 4ln'l' ( ). For both ions, the configuration complexes with a hole in the 3p inner shell contribute almost 10% to the total DR rate coefficient, while the complexes with a hole in the 3s inner shell contribute about 1%. The converging contributions of the 3d 9 4ln'l' (n' > 9) configurations are evaluated by applying the complex-by-complex extrapolation method and are found to comprise up to about 20% of the total DR rate coefficients throughout a wide electron temperature range. The total DR rate coefficients are fitted to an easy-to-use analytic expression which reproduces the original data with an accuracy of about 2% or better in a very wide temperature range.

Structural relaxation and its influence on the elastic properties and notch toughness of Mg–Zn–Ca bulk metallic glass

Radiation induced degradation of widely used bipolar voltage comparators was investigated in wide temperature range from high to liquid nitrogen temperatures. It was obtained, that the parametric degradation is significantly greater at low temperature measurements.

The mostly widely used lithium (Li) batteries, including lithium-ion (Li-ion) batteries, are activated via organic solvent based electrolytes that are highly flammable. The flammable electrolyte can potentially impose impediments to large-format battery device implementation because, under abuse conditions (e.g., internal short circuit, overcharge, crush, etc.), Li batteries can be hazardous due to heat generation which can potentially lead to toxic/flammable material release, fire and over-pressurization/explosion [1]. These hazards represent major concerns for power source platforms populated by personnel, sensitive equipment and/or vital structures. Recent high-profile incidents involving energy dense batteries (e.g., the Boeing 787 Dreamliner battery fire incident [2]) have increased public awareness of battery safety and resulted in intensified scrutiny for the processes used to develop, manufacture, certify and transport Li batteries. Here we present ADA efforts in the development of a Li battery technology comprised from a nonflammable, high performance, room temperature ionic liquid (RTIL)-based or hydrofluoroether (HFE)-based electrolytes and a nano-engineered, atomic layer deposition (ALD) functional material coated, high voltage, high energy density cathode (i.e., high voltage LiCoO2 or HV-LCO). We demonstrate that such combinations can afford a Li battery technology with an unprecedented high energy density (over state-of-the-art Li-ion or Li batteries), high rate capability, a wide operation temperature range, long cycle life at room temperature (RT) and temperature extremes and safety. Figure 1 shows electrolyte flammability test results. A lighter was used to ignite the electrolyte in a watch glass dish in open air. An organic solvent based, Li-ion battery baseline (conventional) electrolyte was ignited and self-burning when the ignitor was moved away. Each of the RTIL- and HFE-based electrolytes did not ignite and, no self-combustion was observed. Figure 2 shows discharge voltage profiles of Li/HV-LCO cells with RTIL- and HFE-based nonflammable electrolytes as a function of temperature. The cells were cycled between 3-4.6V. At RT, the cells delivered a high specific capacity/energy (> 200 mAh/g and > 800 Wh/kg, cathode active weight). At 50°C, the cells delivered a slightly higher (1-3%) specific capacity than RT. At -20°C, the cells were cycled at C/10 rate and delivered ~75% of the capacity at RT (~155 mAh/g). At -40°C, the cells were cycled at C/20 rate. The HFE-based electrolyte cell delivered a much higher specific capacity (66.5 mAh/g) than the RTIL-based (negligible). Figure 3 shows excellent rate capability of the RTIL-based electrolyte with 85% capacity retention at 10C rate. Figure 4(a) shows high voltage cycle life between 3-4.6V at RT for pristine LCO and HV-LCO based Li cells using the RTIL-based electrolyte. The pristine LCO cells experienced a rapid capacity fade while the HV-LCO cells demonstrated excellent cycle life stability with > 92% capacity retention after 100 cycles. We attribute the excellent HV-LCO high voltage cycle performance to the ALD functional material coating on LCO; this coating effectively suppresses the degradation root cause, i.e., the Co4+ dissolution and hexagonal to monoclinic phase transition [3]. We also evaluated cycle life at an extreme high temperature of 75°C. Figure 4(b) shows high voltage cycle life test data for pristine LCO and HV-LCO based lithium cells using RTIL-based electrolyte with additives. The cells were cycled between 3-4.5V. The pristine LCO based cell still faded much more quickly than the HV-LCO based cell; the latter exhibited an extraordinary high voltage high temperature cycle resiliency (97% capacity retention after 30 cycles, vs. 75% of the pristine LCO) even at the extreme high temperature of 75°C. We attribute the outstanding cycle stability at 75°C to the synergistic benefits of nano-engineered cathode and passivation protection from the electrolyte additives. Our study highlights the importance of combining high performance, safe electrolyte with nano-engineered cathode (e.g., ALD nano-engineered LCO) to render the resultant lithium battery with unprecedented energy density (gained from the high voltage operation), high rate capability, safety (nonflammability) and robust cycle life over a wide temperature range particularly at the extreme high temperatures (e.g., 75°C). We demonstrate that our Li battery technology is ideally suited for many high energy density and safety demanding applications, such as, electric drive vehicles, consumer electronics, medical, space and military applications. References Peter Roth and Christopher J. Orendorff, Electrochem. Soc. Interface, Summer 2012, page 44.“FAA Grounds Boeing 787 Dreamliner for Battery Problems”, Aviation International News, January 2013Akira Yano, Masahiro Shikano, Atsushi Ueda, Hikari Sakaebe, and Zempachi Ogumi, Electrochem. Soc., 164, A6116 (2017). Figure 1