Conventional Experimental Setups Research Articles

Analytical model for corona discharge-based electrohydrodynamic plasma actuator incorporating environmental conditions

The electrohydrodynamic (EHD) actuator system, which produces thrust by ionizing a gas and accelerating it, is a novel propulsion system for near space vehicles. In this paper, an analytical model for EHD actuators, called EHD-AM, has been presented to estimate the thrust produced by the actuators in a wire-to-cylinder configuration. Experimental data from six previous studies have been used to validate the model and the mean absolute percentage error (MAPE) between each configuration and EHD-AM has been calculated under different environmental conditions. Based on the evaluations, the MAPE between EHD-AM and the experimental results for different pressures and wire-to-airfoil structures is 7.18% and 6.16%, respectively. The MAPE between EHD-AM and the experimental data measured by particle image velocimetry (PIV) method and with conventional experimental setups is 10.59% and 6.76%, respectively. Based on the EHD-AM, at a constant voltage, the relation between thrust and pressure has a local minimum and a local maximum point in the range of 0.05–1 atm. From 0.05 atm to 0.5 atm, as the pressure increases, the thrust decreases and then increases. As the pressure increases from 0.5 to 1 atm, the thrust decreases. In addition, a higher voltage can result in a higher pressure at which thrust is maximized. Furthermore, the generated thrust is monotonically increasing as the voltage amplitude increases. By implementation of EHD-AM thrust scale in a simple numerical model, the thrust generated by the actuator has been computed and simulated numerically. Initially, the numerical model was verified using experimental results from a previous study. The MAPE between the numerical model and the EHD-AM is 24.08%. Finally, when the interelectrode gap, the collector radius and the emitter radius are relatively large, the thrust of the actuator is predicted by EHD-AM and compared with the numerical results. EHD-AM can be used in the design and optimization of EHD actuators, and also for controller design and related analyses in a control system.

Multi-Dimensional Spectral Single Molecule Localization Microscopy.

Single molecule localization (SML) and tracking (SPT) techniques, such as (spt)PALM, (u/DNA)PAINT and quantum dot tracking, have given unprecedented insight into the nanoscale molecular organization and dynamics in living cells. They allow monitoring individual proteins with millisecond temporal resolution and high spatial resolution (<30 nm) by precisely localizing the point spread function (PSF) of individual emitters and tracking their position over time. While SPT methods have been extended to study the temporal dynamics and co-organization of multiple proteins, conventional experimental setups are restricted in the number of proteins they can probe simultaneously and usually have to tradeoff between the number of colors, the spatio-temporal resolution, and the field of view. Yet, localizing and tracking several proteins simultaneously at high spatial and temporal resolution within large field of views can provide important biological insights. By employing a dual-objective spectral imaging configuration compatible with live cell imaging combined with dedicated computation tools, we demonstrate simultaneous 3D single particle localization and tracking of multiple distinct species over large field of views to be feasible without compromising spatio-temporal resolution. The dispersive element introduced into the second optical path induces a spectrally dependent displacement, which we used to analytically separate up to five different fluorescent species of single emitters based on their emission spectra. We used commercially available microscope bodies aligned one on top of the other, offering biologists with a very ergonomic and flexible instrument covering a broad range of SMLM applications. Finally, we developed a powerful freely available software, called PALMTracer, which allows to quantitatively assess 3D + t + λ SMLM data. We illustrate the capacity of our approach by performing multi-color 3D DNA-PAINT of fixed samples, and demonstrate simultaneous tracking of multiple receptors in live fibroblast and neuron cultures.

Path-optimized nonadiabatic geometric quantum computation on superconducting qubits

Quantum computation based on nonadiabatic geometric phases has attracted a broad range of interests, due to its fast manipulation and inherent noise resistance. However, it is limited to some special evolution paths, and the gate-times are typically longer than conventional dynamical gates, resulting in weakening of robustness and more infidelities of the implemented geometric gates. Here, we propose a path-optimized scheme for geometric quantum computation (GQC) on superconducting transmon qubits, where high-fidelity and robust universal nonadiabatic geometric gates can be implemented, based on conventional experimental setups. Specifically, we find that, by selecting appropriate evolution paths, the constructed geometric gates can be superior to their corresponding dynamical ones under different local errors. Numerical simulations show that the fidelities for single-qubit geometric phase, π/8 and Hadamard gates can be obtained as 99.93%, 99.95% and 99.95%, respectively. Remarkably, the fidelity for two-qubit control-phase gate can be as high as 99.87%. Therefore, our scheme provides a new perspective for GQC, making it more promising in the application of large-scale fault-tolerant quantum computation.

Microfluidic Evolution-On-A-Chip Reveals New Mutations that Cause Antibiotic Resistance.

Microfluidic devices can mimic naturally occurring microenvironments and create microbial population heterogeneities ranging from planktonic cells to biofilm states. The exposure of such populations to spatially organized stress gradients can promote their adaptation into complex phenotypes, which are otherwise difficult to achieve with conventional experimental setups. Here a microfluidic chip that employs precise chemical gradients in consecutive microcompartments to perform microbial adaptive laboratory evolution (ALE), a key tool to study evolution in fundamental and applied contexts is described. In the chip developed here, microbial cells can be exposed to a defined profile of stressors such as antibiotics. By modulating this profile, stress adaptation in the chip through resistance or persistence can be specifically controlled. Importantly, chip-based ALE leads to the discovery of previously unknown mutations in Escherichia coli that confer resistance to nalidixic acid. The microfluidic device presented here can enhance the occurrence of mutations employing defined micro-environmental conditions to generate data to better understand the parameters that influence the mechanisms of antibiotic resistance.

The IR-Large-Temperature-Jump method: Determining heat and mass transfer coefficients for adsorptive heat transformers

The design of adsorptive heat transformers (adsorption heat pumps and chillers and adsorption thermal energy storage) requires knowledge on the heat and mass transfer resistances in adsorbents. However, heat and mass transfer cannot be distinguished in conventional experimental setups, since only pressure data is available. In this work, we present an approach to distinguish and quantify heat and mass transfer resistances in adsorbents. For this purpose, we extended the Large-Temperature-Jump method (LTJ) with an infrared camera (IR) and combined the new IR-LTJ method with dynamic modeling. The IR camera determines the surface temperature of the adsorbent as an additional information. Subsequently, the data from the IR-LTJ setup is used in dynamic models to quantify time-resolved heat and mass transfer coefficients. We conducted experiments for one layer of granulated Fuji Siogel for use in an adsorption chiller with the temperature set 10/30/70. We show that the suggested method is able to determine heat and mass transfer coefficients.

Multicolor 3D Single Particle Tracking using Spectrally Displaced Localization

Single particle tracking (SPT) techniques such as sptPALM, uPAINT, and quantum dot tracking have given unprecedented insight into molecular dynamics in living cells. They allow monitoring the behavior of individual proteins in the plasma membrane as well as their molecular interaction with scaffold proteins at millisecond temporal resolution and high spatial resolution (<30 nm) by fitting the point spread function (PSF) of the individual emitter. While these SPT methods have been extended to study the temporal dynamics and co-organization of multiple proteins, conventional experimental setups used to perform multicolor imaging are typically limited to two simultaneous wavelengths. Increasing the number of colors requires additional filters for specific fluorescent tags and is usually performed at the expense of a loss of spatial or temporal resolution. This limits the minimum diffusion coefficient that can be measured, thereby degrading the ability to differentiate between molecular diffusion regimes like immobilization and confined diffusion.By employing a dual collection objective imaging configuration compatible with live cell imaging, we will present a single molecule tracking technique that allows for simultaneous 3D single particle tracking of multiple distinct species without compromising the spatio-temporal resolution. A dispersive element introduced into the second optical path induces a spectrally-dependent displacement, which is used to separate numerous fluorescent species of single emitters based on their emission spectra. We will present the system's spectral separation capabilities in a quantitative manner and validate the technique in fixed samples. We will conclude by demonstrating the ability to simultaneously track several fluorescing species in live cells.

Ultrafast thermal charging of inorganic nano-phase change material composites for solar thermal energy storage

Ultrafast charging of NG–PCM and CNT–PCM nanocomposites has been demonstrated using a conventional heating approach and direct solar illumination experimental setups.

Nonlinear experiments : a saturation example

Most control system are influenced by static nonlinearities. It is important for an engineer to understand which is the effect of these nonlinearities. Unfortunatelly most hands-on laboratory can not be used for these type of experiences. In this paper it is described an ongoing project which adapts most conventional experimental setups to allow them to be used for nonlinear experiencies. In particular, the saturation case is described.

Determination of methane yield of cellulose using different experimental setups.

In this work, biochemical methane potential (BMP) tests with cellulose as a model substrate were performed with the aid of three manually operated or conventional experimental setups (based on manometer, water column and gas bag) and one automated apparatus specially designed for analysis of BMP. The methane yields were 340 ± 18, 354 ± 13, 345 ± 15 and 366 ± 5 ml CH4/g VS obtained from experimental setups with manometer, water column, gas bag, and automatic methane potential test system, which corresponded to a biodegradability of 82, 85, 83 and 88% respectively. The results demonstrated that the methane yields of cellulose obtained from conventional and automatic experimental setups were comparable; however, the methane yield obtained from the automated apparatus showed greater precision. Moreover, conventional setups for the BMP test were more time- and labour-intensive compared with the automated apparatus.

Fiber Optic Projection-Imaging System for Shape Measurement in Confined Space

A fiber-based projection-imaging system is proposed for shape measurement in confined space. Owing to the flexibility of imaging fibers, the system can be used in special scenarios that are difficult for conventional experimental setups. Three experiments: open space, closed space, and underwater are designed to demonstrate the strength and weakness of the system. It is shown that when proper alignment is possible, relatively high accuracy can be achieved; the error is less than 2% of the overall height of a specimen. In situations where alignment is difficult, significantly increased error is observed. The error is in the form of gross-scale geometrical distortion; for example, flat surface is reconstructed with curvature. In addition, the imaging fibers may introduce fine-scale noise into phase measurement, which has to be suppressed by smoothing filters. Based on results and analysis, it is found that although a fiber-based system has its unique strength, existing calibration and processing methods for fringe patterns have to be modified to overcome its drawbacks so as to accommodate wider applications.

Determination of the Raman depolarization ratio in optically active samples

Raman spectroscopy is a standard analytical technique in many areas. The depolarization ratio is a helpful parameter in the analysis and interpretation of Raman spectroscopic data. However, its determination is not straightforward when an optically active sample is investigated because the polarization state of the incident light is changing as it propagates through the sample. The same applies to the Raman signal. Chiral molecules are very common in the life sciences and hence the knowledge about the influence of the optical activity on the Raman signal is crucial for an accurate interpretation. In this letter we present an approach that can take optical activity into account using conventional experimental Raman set-ups. When the geometric details of the experiment are well characterized, the errors introduced by the optical activity can be corrected.

Coherent anti-Stokes Raman scattering microscopy using a single-pass picosecond supercontinuum-seeded optical parametric amplifier

We have demonstrated coherent anti-Stokes Raman scattering (CARS) microscopy with a single-pass picosecond supercontinuum-seeded optical parametric amplifier (SCOPA). The SCOPA was pumped by a frequency-doubled picosecond passively mode-locked Nd:YVO(4) laser, and was seeded by a supercontinuum light source. Compared with the conventional experimental setups of CARS microscopy, our exposition is substantially simpler because the pump and Stokes lasers are overlapped in the SCOPA automatically and thus steered into a microscope coherently. The feasibility of this novel light source to CARS imaging was illustrated by acquiring the fundamental and overtone CARS images of the aromatic C-H stretching mode of polystyrene beads and an image of the pharynx of a C. elegans of the aliphatic C-H stretching mode.

Recovery of neurophysiological features with time after rat sciatic nerve repair: a magneto‐neurographic study

Experimental assessment of peripheral nerve regeneration in rats by electrophysiology is controversial due to low reproducibility of electrophysiological indicators and diminished quantitative evaluation in conventional experimental set-ups. Magnetoneurography (MNG) counteracts these drawbacks by magnetically recording electrophysiological signals ex vivo, thereby providing accurate and quantitative data. In 50 rats, sciatic nerve transection was followed by direct repair. MNG outcome parameters, footprints [static toe spread factor (TSF); function] and muscle weight (MW) were studied for their recovery pattern from 2 to 24 weeks. By using MNG, we showed that the regeneration process still continues when functional recovery (static TSF) becomes stagnant. With regression analysis, MNG parameters amplitude, amplitude area and conduction velocity (CV) demonstrated moderate significant correlation with MW, whereas CV was not significantly associated with static TSF. No significant association exists between MW and static TSF. A Kaplan-Meier survival curve revealed that autotomy/contracture of rat hind paws was not related to decreased MNG outcome values. In conclusion, this study highlights and discusses the dissimilarities between direct (MNG) and indirect (static TSF and MW) assessment techniques of the regeneration process. We emphasise the significance of MNG as a direct derivative of axon regeneration in experimental rat studies. Additionally, we stress the must for right-left ratios, as neurophysiological indicators vary with age, and we confute possible bias in footprint analysis caused by exclusion of autotomy/contracture animals.

Structural refinements of the individual grains within polycrystals and powders

A method is presented for simultaneous structural refinement of up to several hundred grains inside powders or polycrystals. The method is based on the use of hard X-rays and the indexing programGRAINDEX, where grain orientations are found by scanning in Euler space. Conventional experimental setups and refinement programs for single-crystal work can be applied. The method is validated by a study of a sintered plate of α-Al2O3, containing of the order of 1500 grains in the gauge volume. 57 of the largest grains were refined with respect to the Alzand Oxpositions as well as the isotropic atomic displacement parameters. TheR1 values were 3.4% and 3.8% for the grain average and the best grain, respectively. A discussion of the potential of the method is presented, as well as the main limitation: grain size and overlap of diffraction spots.

Esterification of Benzoic Acid with 2-Ethylhexanol in a Microwave Stirred-Tank Reactor

A microwave applicator with a 2.45-GHz magnetron generator, which provides 460 W of output power, and waveguides to a stirred-tank reactor with a full volume of 500 mL was designed. The microwave reactor operates at high pressure and high temperature. Esterification of benzoic acid with 2-ethylhexanol was chosen as the model reaction. The esterification was homogeneously catalyzed with sulfuric acid and para-toluene sulfonic acid. As heterogeneous catalysts, Cs2.5H0.5PW12O40, sulfated ZrO2, Fe2(SO4)3, and montmorillonite KSF were used. For the same operating conditions, the rate of esterification was concluded to be the same in both the microwave reactor and conventional experimental setups. The results show that homogeneous catalysts are more effective than heterogeneous catalysts. Fe2(SO4)3 was the most effective catalyst among the solid catalysts tested. The conversions in the microwave stirred-tank reactor were in agreement with the conversions predicted on the basis of the kinetic parameters obtained...

A Computer-Based Voltage Control Experiment for Advanced Power System Operation Teaching

This paper presents the development of a computer-based electrical power system control experiment for advanced undergraduate students in Electrical Power Engineering. Using the experiment, the student is trained in understanding power system voltage performance in operation and the control measures in abnormal conditions. The computer-based experiment method could enhance student appreciation of concepts and offer a cost-effective solution to the problem of expensive conventional hardware experimental setups. Simulation examples with test power systems and discussions of users' feedback are presented to show the effectiveness of the method.

A computer-controlled research ventilator for small animals: design and evaluation.

The understanding of the mechanical properties of the mammalian respiratory system and how they change under the influence of drugs and in disease are frequently pursued in small animals, since they can be easily obtained in large numbers as pure-bred strains. However, conventional experimental set-ups for studying small animals are generally limited in their ability to measure gas flow into the lungs. In this paper, we present a computer-controlled research ventilator for small animals which can provide conventional mechanical ventilation as well as arbitrary flow perturbations with a bandwidth from 0-55 Hz. Respiratory impedance is estimated from the displacement of the piston and the pressure it generates, thereby obviating the need for a direct flow measurement. The performance of the device was tested on mechanical loads whose impedances were calculated theoretically. The measured and predicted loads agreed within less than 5% up to 30 Hz. Furthermore, the measured impedance of two mechanical loads in series precisely matched the sum of their individual impedances.