Comprehensive Experimental Method Research Articles

An Inductive Method for Comprehensive Estimation of Temperature-Dependent Electrical and Thermal Properties of Conductive Ferromagnetic Materials

Reliable information about the properties of the processed materials has a significant impact on the effects of their processing. In induction heating processes, this also applies to information about the influence of temperature T on these properties. These are both thermal and electro-magnetic properties. Based on previous studies, a comprehensive experimental method is presented for estimating the temperature characteristics of thermal diffusivity, volumetric heat capacity and resistivity on one measurement station, with particular attention to ferromagnetic materials. The estimation process is carried out on an induction heating stand using forcing signals from an inverter generator. In a computer-controlled cycle that changes the base temperature level, basic measurements of thermal and electrical properties are carried out on a material sample in the form of a cylindrical disk. They are the results of the analysis of the temperature and electromagnetic responses of a material sample to short- and long-term step pulses of a sinusoidal excitation signal with a frequency of approximately 40 kHz. The presented estimation method can be treated as a final method or a preliminary procedure for radically narrowing the variability in decision variables inthe optimization process of simultaneous determination of the sought material characteristics.

Regulation of Nrf2/A20/eEF1A2 Axis by Ginsenoside Rb1: A Key Pathway in Alleviating Cerebral Ischemia-Reperfusion Injury.

Cerebral ischemia-reperfusion injury (CIRI) is a prevalent neurological disorder, characterized by the oxidative stress and inflammatory response induced during the ischemia-reperfusion process, leading to significant damage to brain cells. Ginsenoside Rb1, a natural medicinal ingredient, possesses potential neuroprotective effects. This study aims to investigate the mechanism of action of ginsenoside Rb1 in CIRI and its protective effects on brain injury. We utilized a mouse CIRI model and randomly divided the mice into control group, CIRI group, and ginsenoside Rb1 treatment group. The effects of Rb1 on brain tissue damage, apoptosis, expression of inflammatory factors, and pyroptotic cell numbers in CIRI mice were observed through triphenyl tetrazolium chloride (TTC) staining, terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) staining, real-time reverse transcription polymerase chain reaction (qRT-PCR), and electron microscopy. In a cell model, the regulatory effect of Rb1 on oxygen-glucose deprivation/reperfusion (OGD/R)-induced HT22 cell pyroptosis via the nuclear respiratoty factor 2/tumor necrosis factor-α (TNF-α)-induced Protein 3 (TNFAIP3, aka A20)/eukaryotic translation elongation factor 1A2 (Nrf2/A20/eEF1A2) axis was detected using Western blot and TUNEL staining. Additionally, the impact of Nrf2 inhibitor ML385 and eEF1A2 overexpression on the neuroprotective effect of Rb1 was assessed. Using the comprehensive experimental methods mentioned above, the neuroprotective mechanism of Rb1 in CIRI was thoroughly evaluated. Our findings demonstrate that treatment with ginsenoside Rb1 alleviated behavioral deficits induced by CIRI and reduced pathological damage in brain tissue. Furthermore, ginsenoside Rb1 treatment notably decreased oxidative stress and the inflammatory response induced by CIRI, leading to lower levels of inflammatory factors (p < 0.05). Further experimental results indicated that ginsenoside Rb1 promoted antioxidant and anti-inflammatory responses by regulating the activity of the Nrf2/A20/eEF1A2 axis. Additionally, ginsenoside Rb1 inhibited the activation of the NOD-like receptor thermal protein domain associated protein 3 (NLRP3) inflammasome, thereby reducing the release of inflammatory factors and the occurrence of cell apoptosis. Our study results suggest that ginsenoside Rb1 exerts neuroprotective effects and alleviates brain injury induced by CIRI by regulating the Nrf2/A20/eEF1A2 axis and inhibiting the activation of the NLRP3 inflammasome. These findings provide new treatment insights for CIRI and support ginsenoside Rb1's development as a therapeutic drug. However, despite the promising nature of our findings, further research is required to validate these discoveries and explore the feasibility and safety of ginsenoside Rb1 in clinical applications. We hope that our study can provide new directions and strategies for the treatment and prevention of CIRI, contributing to the development of neuroprotective drugs.

Thermal Bridges Monitoring and Energy Optimization of Rural Residences in China’s Cold Regions

With the worldwide dissemination of the “green development” concept and the advancement of China’s new rural construction, the sustainable development of rural residences has gained significant attention within the construction industry. This article focuses on large-scale prefabricated insulation block houses used in China’s cold regions, specifically examining the case of Defa Village in Nenjiang City, Heilongjiang Province. By utilizing thermal imaging cameras, the thermal bridge parts of these houses are detected, and a finite element model is established to optimize the comprehensive heat transfer coefficient of these areas. This optimization is achieved by expanding the insulation layer and implementing low thermal bridge structures, ultimately enhancing the insulation and energy-saving efficiency of the houses. Simultaneously, an energy-saving analysis is conducted based on an optimized enclosure structure scheme, considering seven key design factors that influence building energy consumption: span, depth, clear height, and window-to-wall ratio in all four directions. Through a comprehensive experimental method, the building energy consumption is evaluated, and a scheme with optimal values is proposed. The results demonstrate that the insulation block walls and the main structures with expanded insulation layers and low thermal bridge structures are easier to construct. When compared to the original scheme, the comprehensive heat transfer coefficient of the walls is reduced by 54.82%, while that of the beams and columns is reduced by 97%. Implementing the optimal value scheme leads to a reduction of 66.83% in the building’s overall energy consumption. This research provides valuable guidance for the design and construction of large-scale insulated block rural residences, revealing the substantial potential of rural residences in terms of energy-saving and emission reduction.

Experimental investigation on shear damage evolution of 3D woven composites using in situ computed tomography and multi-scale digital image correlation

A comprehensive experimental method combining microscope observation, multi-scale digital image correlation (DIC) and in situ computed tomography (CT) is proposed to reveal the complex damage evolution of 3D woven composites under short beam shear (SBS) loading. The surface damage process and the final damage mode of the SBS specimen are observed with a microscope, and the cause of fiber kinking is explained. The global and local strain distributions on the specimen surface are obtained by multi-scale DIC, which explain the causes of weft yarn transverse cracks and interface debonding. Finally, the in situ CT experiment is carried out to identify the reasons for the nonlinear segments of the load–displacement curve and the decline of load bearing capacity of the specimen in the late stage of the experiment. The information obtained by different observation methods is complementary, which is conducive to understanding the complex damage mechanism of 3D woven composites.

Screening for Primordial RNA–Peptide Interactions Using High-Density Peptide Arrays

RNA-peptide interactions are an important factor in the origin of the modern mechanism of translation and the genetic code. Despite great progress in the bioinformatics of RNA-peptide interactions due to the rapid growth in the number of known RNA-protein complexes, there is no comprehensive experimental method to take into account the influence of individual amino acids on non-covalent RNA-peptide bonds. First, we designed the combinatorial libraries of primordial peptides according to the combinatorial fusion rules based on Watson-Crick mutations. Next, we used high-density peptide arrays to investigate the interaction of primordial peptides with their cognate homo-oligonucleotides. We calculated the interaction scores of individual peptide fragments and evaluated the influence of the peptide length and its composition on the strength of RNA binding. The analysis shows that the amino acids phenylalanine, tyrosine, and proline contribute significantly to the strong binding between peptides and homo-oligonucleotides, while the sum charge of the peptide does not have a significant effect. We discuss the physicochemical implications of the combinatorial fusion cascade, a hypothesis that follows from the amino acid partition used in the work.

Investigation of pore structure characteristics in marine deep-water high-temperature and high-pressure sandstone: A comprehensive characterization combining various experimental techniques

Marine deep-water high-temperature and high-pressure (HTHP) reservoirs have excellent potential for future oil and gas exploration. Because reservoir quality is often influenced by pore structure, understanding the characteristics of pore structures is essential for efficient exploitation. Therefore, it is necessary to conduct a comprehensive study of the pore structures in HTHP reservoirs. This study selected samples of the Enping Formation in the South China Sea as the research target and investigated the reservoir pore structures based on scanning electron microscopy, casting thin section, nuclear magnetic resonance, and mercury intrusion (e.g., high-pressure, constant-rate). The results show that the pore geometry and throat radius of different pore types in these reservoirs can lead to pore system heterogeneity. A comprehensive experimental method combining NMR and mercury injection was used to determine pore structure characteristics. In addition, a new pore size classification scheme was developed for marine deep-water HTHP reservoirs, and the controlling effect of pore type on percolation flow capacity was analyzed. This study systematically used a comprehensive pore structure characterization method that combined various experimental techniques to present the pore structure and develop a new pore size classification scheme for deep-water HTHP sandstone reservoirs, providing insight into the reservoir quality of marine deep-water HTHP sandstone reservoirs.

High-Throughput Preparation and Machine Learning Screening of a Blue-Phase Liquid Crystal Based on Inkjet Printing.

Blue-phase liquid crystal (BPLC) is considered as the next-generation liquid crystal display material, but its practical application is seriously affected by a narrow temperature range and a long research period. In this paper, we used inkjet printing technology to prepare BPLC materials with high throughput, and try to use machine vision technology to test BPLC with high throughput. The “standard curve method” for establishing each printing channel and the “vector matching method” for searching the chromaticity value of the minimum distance were proposed to improve the accuracy of inkjet printing BPLC materials. For a large number of sample-phase images, we propose a machine learning method to identify the liquid crystal phase. In this paper, for the first time, the high-throughput preparation and high-throughput detection of 1080 BPLC samples with five common components by a comprehensive experimental method has been successfully realized. The results are helpful to improve the research efficiency of blue-phase materials and provide a theoretical basis and practical guidance for rapid screening of multi-component BPLC materials.

An experimental study of the dynamic responses of carbon fiber reinforced polymer composite laminates subjected to ice impact

The aircraft structures are threatened by soft material impact such as birds and hail ices. The main objective of this study is to develop a comprehensive experimental method to evaluate the resistance performance of carbon fiber reinforced polymer laminate subjected to ice impact loadings. First, a hollow tube sensor was adopted to measure the impact force of ice projectiles. Based on the deformation process captured by a high-speed camera and the analysis on transmitted energies obtained by the tube sensor, the repeatability of the ice impact loadings was confirmed and its impact behavior was analyzed. Second, six T700/epoxy carbon reinforced polymer laminates were impacted with different loading velocities, where the transient deformation data during impact were obtained by 3D digital image correlation method The post-test detection was realized using both optical microscopes and scanning acoustic microscopes. The impact of ice projectiles resulted in distributed loadings on the laminate targets with invisible inner matrix cracks and delaminations. Irregular distributions of delaminated areas subjected were observed and their sized increased with the impact velocity. The experimental method showed its practicability on impact issues with projectiles of unknown properties.

Direct 3D observation and unraveling of electroconvection phenomena during concentration polarization at ion-exchange membranes

A decade ago, two-dimensional microscopic flow visualization proved the theoretically predicted existence of electroconvection roles as well as their decisive role in destabilizing the concentration polarization layer at ion-selective fluid/membrane interfaces. Electroconvection induces chaotic flow vortices injecting volume having bulk concentration into the ion-depleted diffusion layer at the interface. Experimental quantification of these important flow patterns have so far only been carried out in 2D. Numerical direct simulations suggest 3D features, yet experimental proof is lacking. 3D simulations are also limited in covering extended spacial and temporal scales.This study presents a new comprehensive experimental method for the time-resolved recording of the 3D electroconvective velocity field near a cation-exchange membrane. For the first time, the spatio-temporal velocity field can be visualized in 3D at multiples of the overlimiting current density. In contrast to today’s simulations, these experiments cover length and time scales typical for actual electrodialytic membrane processes.We visualize coherent vortex structures and reveal the changes in the velocity field and its statistics during the transition from vortex rolls to vortex rings with increasing current density. The transition is characterized by changes in the rotational direction, mean square velocity, and temporal energy spectrum with only little influence on the spatial spectrum. These findings indicate a more significant impact of EC’s structural change on the mean square velocities and temporal spectra than on the spatial spectra. This knowledge is a prerequisite for engineering ion-selective surfaces that will enable the operation of electrically driven processes beyond the diffusion-limited Nernst regime.

A comprehensive numerical investigation of unsteady-state two-phase flow in gravity assisted heat pipe enclosure

In this study, thermal performance analysis of glass and copper two-phase closed thermosyphons (TPCTs) were investigated as 3D using comprehensive experimental methods and a new combined numerical model containing two stages. For this purpose, Volume of Fluid model has been used for the first 60 s, and Eulerian model has been employed after 60 s until 180 s for the first time in the literature. For the verification of this numerical analysis, the surface temperatures of TPCTs were measured at twenty different points by K-type thermocouples. The pressure change inside the pipes was measured by a vacuum manometer. A video camera was utilized to observe the change of steam and water volumes in the glass TPCT. The experimental and numerical results were also compared with each other in real-time for the first time in the literature. According to results, the numerical temperature distributions and steam volumes in TPCTs have shown a similar trend with the studies in the literature. It was observed that the maximum absolute temperature difference values in the evaporation, middle and condenser regions for TPCTs ranged from 6.81 K to 18.63 K. These values are similar to the values in the other studies. The maximum absolute temperature difference values were calculated between 12.09 K and 26.07 K for different turbulence models.

Experimental framework for identifying inconsistent measurements in frequency-based substructuring

The dynamic properties of modern products are analysed using an experimental approach through the measurement of frequency–response functions (FRFs). For an individual measurement, the coherence offers an online check during the system acquisition. More general tools for determining the consistency of the complete measurement set are based on a comparison of the FRFs or the modal shapes with a numerical model. They are useful tools, but they rely on a comparison with a numerical model that might not reflect the behaviour of the actual system. This paper aims to develop a comprehensive experimental method to check the consistency of individual measurements based on comparisons with the complete experimental response model. The numerical model is introduced only to enable the experimental model to be expanded using the System Equivalent Model Mixing method. The entire formulation is developed in the frequency domain, so that the transition to the modal domain, which might remove the physically relevant information from the system, is not required. In the frequency domain, it is possible to assess the consistency of the FRF across the entire frequency range of interest and not only in the region of the natural frequencies. This is of great importance in the area of frequency-based substructuring, where even small inaccuracies in the substructure’s FRFs (e.g., the position of the anti-resonance) can lead to erroneous coupling results due to the inversion process. The experimental case study demonstrates the efficiency of the proposed approach. By removing the identified inconsistent measurements, it was possible to significantly increase the accuracy of the final coupling process.

Temperature‐dependent dynamic R DS,ON under different operating conditions in enhancement‐mode GaN HEMTs

High-voltage enhancement-mode (E-mode) gallium nitride (GaN) high electron mobility transistor (HEMT) is a superior candidate to enable higher efficiency and higher power density when compared with silicon power devices in power converter applications. However, the dynamic R DS , ON problem affects the conduction loss of the converter and remains one of the major issues that must be resolved. In this study, a comprehensive experimental evaluation and analysis method of the temperature-dependent dynamic R DS , ON of GaN HEMT in a circuit level is proposed. A commercial E-mode GaN HEMT (GS66508T) is used as a sample to study the temperature-dependent dynamic R DS , ON using a double-pulse-tester. The temperature-dependent dynamic R DS , ON under different DC-link voltages and different load currents are studied and the results show a non-monotonic temperature-dependence of the dynamic R DS , ON . It is concluded that the temperature dependence of the buffer-induced trapping and de-trapping effect, and the temperature dependence of electron mobility together influence the dynamic R DS , ON of E-mode GaN HEMT device during operation. This finding is important since in converter applications the devices are typically operating at elevated temperatures. The proposed comprehensive experimental method can be used to estimate and analyse the dynamic R DS , ON characteristics of other GaN devices.

A comprehensive analysis of fracture initiation and propagation in sandstones based on micro-level observation and digital imaging correlation

Along with the development of the oil & gas industry, the word "fracture" is now a quite familiar subject to well stability and integrity over the drilling process. However, the fracturing mechanisms are still less convincing though a large amount of literature have addressed the subject matter. In this paper, a new comprehensive experimental method is proposed herein to analyze the fracturing mechanisms through a micro-level observation to a macro explanation.To assess the tensile resistance of rock, Brazilian Test was applied to disc-shaped specimens of isotropic sandstones. Meanwhile, a high-speed photography system was keeping snapping images for the digital imaging correlation (DIC) to get a dynamic fracturing process. After the specimen failed and was split, the cuttings were analyzed using scanning electron microscope (SEM) and electron-dispersive system (EDS) for a micro-level observation.Two kinds of fracturing mechanisms were identified as: (1) grain fracturing, and (2) pore-fillings fracturing. Three basic fracture modes (Mode I/II/III) can also be distinguished through (1) the grain size, and (2) the grain shape and uniformity using a new parameter named angularity factor. The DIC technique proved to be a powerful analysis tool, especially showing the sequence of fracture initiation, propagation and termination. Though the cracks can be initiated from the center or near the loading points, the main direction of fracturing propagation was still along the diametric loading plane. In addition, a displacement along the thickness was also identified through a 3-D investigation, which should be of interest due to the scarcity of relevant literature in 3-D effect on standard 2-D Brazilian Test.

A Review on Quantitative Measurement of Cell Adhesion Strength.

There is an explosion of interest in characterizing cell adhesion process and the mechanochemical players that is critical to a wide range of physiological and pathological consequences. Much, however, still remains uncertain and controversial about the quantitative measurement of cell adhesion strength (i.e., cell-substratum adhesion force, cell-cell adhesion force, etc.). The main reason for this deficit is a lack of well-established and comprehensive experimental methods that quantitatively measure cell adhesion strength at cellular and even molecular levels. This leads to the need for conducting a literature review on the methods for characterizing the adhesion force of anchorage-dependent cells. In this review article, we discern and critique available techniques for measuring cell adhesion strength that is required for an adherent cell (or cells) of interest to detach from the neighboring cell or the substratum. This review focuses on recent advances in the technique for measuring cell adhesion strength to weigh up the strengths and weaknesses of each technique, together with a brief description for the biological aspects of cell adhesion process. The summary of this article might help us both to develop a standard method for measuring cell adhesion strength and to broaden and deepen our understanding of cell adhesion process.

Microfracture and Surfactant Impact on Linear Cocurrent Brine Imbibition in Gas-Saturated Shale

During and after hydraulic fracturing, fluid–shale interaction has a prominent impact on liquid retention and thus on gas phase permeability and gas productivity. By providing a low surface tension or wettability alteration, surfactants are widely used to decrease liquid retention after fracturing. To evaluate the liquid intake of a rock sample, an imbibition experiment is commonly used, especially when it is treated by a surfactant. However, conventional imbibition experiments with gas shale could not quantitate the imbibition behaviors as it does with conventional rocks because of the low porosity and extremely low permeability of gas shale. In this paper, a comprehensive experimental method was successfully developed to study the liquid imbibition in shale samples. Bulk shale easily fell apart during imbibition experiments. However, samples prepared with the coating method decribed herein remained intact except for fractures generated in them during the first imbibition. On each imbibition curve with i...

The Synergistic Effects of Freeze-Thaw, Salt Attack and Bending Stress on Behavior of Reinforced Concrete

The damage experiments of reinforced concrete (RC) samples under synergistic effects of cyclic freeze-thaw, deicing-salt attack, rebar corrosion and bending stress were investigated using a comprehensive experimental method. Synergistic effects of these factors on the damage evolvement of RC were studied by measuring the change of dynamic modulus of concrete, rebar strain and concrete strain. Experimental results showed similar rule in damage evolvement but different damage rate between the normal-strength concrete (C45, the 28-day compressive strength of 52 MPa) and the high-strength concrete (C70, the 28-day compressive strength of 77 MPa). The dynamic modulus of the reinforced concrete degraded with increasing effecting factors.

Instrumented End Notched Flexure – Crack propagation and process zone monitoring. Part I: Modelling and analysis

Analysis of the three-point bending, End Notched Flexure (ENF), test is presented for exploitation with a new experimental methodology using the backface strain monitoring technique. The model consists of two Timoshenko beams joined with a two parameter elastic foundation, to evaluate stress and strain fields in both adherends and the adhesive layer, together with the specimen compliance and energy release rate. This model is compared to a simplified case, from which a comprehensive experimental method is proposed for precise monitoring of crack propagation and measurement of interface shear compliance during the ENF experiment. In addition, simple formulae are proposed for evaluating mode II energy release rate, and possible experimental artefacts due to asymmetric loading conditions are evidenced.

Study on Start Burning Performance of Micro-ICP Using Stereo Spiral Coil

According to the problem of low energy utilization of plane spiral coil used in micro-ICP, a kind of micro stereo helical coil was designed. Made 24 different structural parameters of stereo spiral coil whose diameter range 3~10 mm. Using comprehensive experimental method tested different parameters’ coils inspire argon plasma. In 13.56MHz RF power, relationships between argon pressure, coil turns, coil diameter and combustion /maintaining power of micro-ICP excitation source were tested. From spectrometer observed 17 argon emission spectrum in 690~860 nm. Spectral lines intensity influenced by RF power and work pressure. Experiments proved that micro-ICP excitation source using stereo helical coil is feasible. It can form Ar plasma and inspire Ar spectral lines.

Assessment of Experimental Pain From Skin, Muscle, and Esophagus in Patients With Chronic Pancreatitis

Comprehensive experimental methods are of major relevance assessing pain mechanisms in patients with chronic pain. Chronic pancreatitis is thought to involve the sensory response in other visceral organs and somatic tissue. We, therefore, aimed at exploring the pain mechanisms in chronic pancreatitis (CP) using a multimodal and multitissue stimulation approach. Ten patients (mean age, 50 years) with CP and 13 healthy controls (mean age, 35 years) participated. None of the patients took analgesics regularly. All were exposed to multimodal (mechanical, thermal, and electrical) experimental pain in the skin, muscles, and esophagus. The patients were hyposensitive to mechanical stimulations of the skin (P = 0.001), but there were no differences in the pain to thermal and electrical stimulations. In the muscle and esophagus, no differences in pain thresholds were found. The difference between single and repeated stimulations reflecting the degree of central sensitization was 17% in controls and 36% in patients (P = 0.001). The referred pain area to electrical stimulation was 30.1 cm2 in the patients and 7.7 cm2 for the controls (P = 0.02). The findings suggest that the balance among central hyperexcitability, neuroplastic changes, and descending pain-modulating pathways may explain the pain response to experimental multimodal stimulations in CP. This will likely also reflect the clinical pain mechanisms and may have important impact in selection of treatment, where drugs with potential effects on these mechanisms should be used.

Protein structural class identification directly from NMR spectra using averaged chemical shifts

Knowledge of the three-dimensional structure of proteins is integral to understanding their functions, and a necessity in the era of proteomics. A wide range of computational methods is employed to estimate the secondary, tertiary, and quaternary structures of proteins. Comprehensive experimental methods, on the other hand, are limited to nuclear magnetic resonance (NMR) and X-ray crystallography. The full characterization of individual structures, using either of these techniques, is extremely time intensive. The demands of high throughput proteomics necessitate the development of new, faster experimental methods for providing structural information. As a first step toward such a method, we explore the possibility of determining the structural classes of proteins directly from their NMR spectra, prior to resonance assignment, using averaged chemical shifts. This is achieved by correlating NMR-based information with empirical structure-based information available in widely used electronic databases. The results are analyzed statistically for their significance. The robustness of the method as a structure predictor is probed by applying it to a set of proteins of unknown structure. Our results show that this NMR-based method can be used as a low-resolution tool for protein structural class identification.