Efficient Transfer Method Research Articles

Bridge Health Monitoring Using Proper Orthogonal Decomposition and Transfer Learning

This study focuses on developing and examining the effectiveness of Transfer Learning (TL) for structural health monitoring (SHM) systems that transfer knowledge about damage states from one structure (i.e., the source domain) to another structure (i.e., the target domain). Transfer Learning (TL) is an efficient method for knowledge transfer and mapping from source to target domains. In addition, Proper Orthogonal Modes (POMs), which help classify behavior and health, provide a promising tool for damage identification in structural systems. Previous investigations show that damage intensity and location are highly correlated with POM variations for structures under unknown loads. To train damage identification algorithms based on POMs and ML, one generally needs to use multiple simulations to generate damage scenarios. The developed process is applied to a simply supported truss span in a multi-span railway bridge. TL is first used to obtain relationships between POMs for two modeled bridges: one being a source model (i.e., labeled) and the other being the target modeled bridge (i.e., unlabeled). This technique is then implemented to develop POMs for a damaged, unknown target using TL that links source and target POMs. It is shown that the trained knowledge from one bridge was effectively generalized to other, somewhat similar, bridges in the population.

Synergistic effect of coating copper foam with carbon nanotubes on pool boiling heat transfer performance

Pool boiling heat transfer is a commonly used method for efficient phase change heat transfer. This paper studied the synergistic enhancement of heat transfer performance of pool boiling in deionized water by introducing an MWCNT (multi-walled nanotube) coating on a foam copper frame, and the influence of MWCNT content was explored. The results showed that the MWCNT coating strengthened the critical heat flux (CHF) and heat transfer coefficient (HTC) compared to a polished Cu surface. When 2.4 mg of MWCNTs were deposited, the maximum CHF was reached (785.2 kW·m−2), 3.41 times that of the polished Cu surface; and when 2.8 mg were deposited, the maximum HTC was reached (33.41 kW·m−2· k−1), 2.50 times that of the polished Cu surface. The results show that this heat transfer surface improves the performance of pool boiling heat transfer. A high-speed camera was used to record the bubble state during the boiling process of the pool. A simulation of the physical model in ANSYS Workbench returned the same results as the experiments.

High-Performance Digital Lock-In Amplifier Module Based on an Open-Source Red Pitaya Platform: Implementation and Applications

A lock-in amplifier (LIA) is an instrument that can extract weak signals from extremely noisy environments, and it is widely used in various precision measurement fields. However, there are still challenges in lock-in techniques in experiments that require high-frequency or multiple lock-in channels, such as high-frequency vibration detection and experiments with quantum sensors. The direct use of commercial LIAs will result in high experimental costs. Herein, a high-performance digital LIA module based on an open-source Red Pitaya (RP) platform is constructed. The quantitative description of the demodulation results, efficient data transfer method, and the development of the automated measurement functions in experiments are carried out in this module. As demonstrations, the phase difference and thermal noise measurements are conducted using the module. The research on temperature sensing with the frequency shift of quartz crystals and semiconductor doping concentration measurements has also been implemented. These demonstrations show that the digital lock-in module has good application prospects.

A simple and efficient transfer method for fabricating stretchable AgNW patterns on PDMS using carboxylated cellulose nanofibers as a sacrificial layer.

Silver nanowire (AgNW) networks are one of the most promising materials of transparent electrodes in flexible applications. However, they still face challenges in fabricating AgNW transparent conductive films (TCFs) with excellent comprehensive performance on stretchable substrates. In this work, we developed an efficient and simple water-assisted method to completely transfer AgNW films from glass to polydimethylsiloxane (PDMS). Carboxylated cellulose nanofibers (CNF-C) are introduced between the AgNW network and glass as a sacrificial layer, which is dissolved in water in the transfer process, releasing the AgNW network on the PDMS. The transferred AgNW networks show an increase of sheet resistance less than 30% and a slight decrease of transmittance. The stretchable AgNW TCFs exhibited good opto-electrical performance with a figure of merit of about 200, low surface roughness, good film uniformity, long-term stability, electrical stability and mechanical performance. Two patterning approaches based on the transfer method were proposed and fine stretchable AgNW patterns with a linewidth of 200 μm were fabricated. The fabricated stretchable AgNW patterns were used in flexible wires, a film heater and sensors as a demonstration.

Design of an Optimum Massive MIMO FSO System and Analysis of its Performance in Different Weather Conditions

This aim of this work is to propose a massive MIMO FSO system with optimum design parameters and analyze its performance in various turbulent weather conditions by simulating the model in Optisystem . In recent years, the need for high speed data transfer for real time communication has become a necessity. Implementation of massive MIMO system has already gained remarkable achievement using the conventional RF transmission system. Although it is very much efficient in its application, it has some problems, such as licensing restrictions, bandwidth depletion, fragmentation. In this respect, Free space optics (FSO) is an efficient method for high speed data transfer as it does not have above limitations. Different researches conducted using MIMO FSO models have shown promising results. The use of massive MIMO system (more than array of antennas) will enhance data rate further. In this research work, an optimum massive MIMO FSO system has been designed with array of antennas. The performance of this system is analyzed in different weather conditions and compared with that of system. The analysis of performance is done by power penalty and receiver sensitivity plots. A significant transmission range and an optimum performance is obtained by using this system at a data rate of Gbps. However, data transmission rate can be much more enhanced in this system at the cost of reduced performance and a shorter transmission range.

An efficient and high-fidelity local multi-mesh finite volume method for heat transfer and fluid flow problems in metal additive manufacturing

The multi-scale and nonlinear feature of additive manufacturing problems poses great challenges to numerical algorithms regarding computational efficiency and fidelity. In this work, we propose a novel local multi-mesh finite volume method for heat transfer and fluid flow problems in the additive manufacturing process. In this method, two sets of meshes (coarse base mesh and finer overlay mesh) are used to resolve the macroscopic temperature field of the whole domain and the mesoscopic heat transfer and fluid flow problem within a relatively small region covering the melt pool, respectively. The interaction between the base mesh and the overlay mesh is handled by the Dirichlet boundary conditions on the interface following the refinement-by-superposition idea, such that the powder-scale simulation is available with high efficiency. The finer mesh with cells of sub-powder size uses the arbitrary Lagrangian–Eulerian description and moves with the heat source to keep coverage of the region with high solution gradients. According to the moving feature of the finer mesh, a particle-volume fraction conversion scheme is introduced to update the material distribution. The local multi-mesh finite volume method is further combined with the discrete element method as well as a surface reconstruction method to alternatively solve the powder layering process and the laser melting process. A set of numerical cases is presented, and the numerical results are compared with analytical and experimental data from the literature, with good agreement in cases where such data is available. Moreover, the computational efficiency of the proposed method is proved to be dozens of times (16∼50 for the given size ratios of the melt pool to the whole domain) of the finite volume method using a uniform structured mesh. It is expected to be a powerful tool for efficiently achieving powder-scale simulation of the additive manufacturing process and other similar multi-scale problems.

Gamma spectrometric measurement of uranium isotopic composition and mass in sintered UO2 pellets using the efficiency transfer method

Gamma spectrometric measurements to determine the isotopic composition and total uranium mass in UO2 pellets (D = 7.5 mm; H = 3.5 mm, ρ = 10 g/cm3) were carried out. The required efficiency curve was obtained by applying the efficiency transfer method from a calibration standard (D = 65 mm; H = 20 mm) of a slightly acidified water solution. The average isotopic composition of ten UO2 pellets was consistent with values of natural uranium given by IUPAC. The average relative bias for the 235U/238U amount ratio was −0.73% using the 1001 keV gamma line for 238U and 0.50% using the 63 keV gamma line (186 keV was always used for 235U). For the total uranium mass, the mean deviation as compared to mass determinations using a balance was 5.5% using the 1001 keV gamma line for 238U and 4.3% using the 63 keV gamma line.

Large-Area Free-Positioning Wireless Power Transfer to Movable Receivers

This article introduces a method for efficient and robust free-positioning wireless power transfer (WPT) in a large area, which can be applied to many use cases, including wireless charging of industrial robots, drones, and electric scooters. In these large areas of WPT applications, multiple transmitters (Txs) are placed in a pad-like area, and the Tx coils are optimally excited to enable robust and efficient power transfer to movable receivers within the charging area. The proposed configuration enables almost continuous magnetic flux path from a set of Tx coil(s) to another set of Tx coil(s) through the receiver coil ferrite core. Therefore, efficient power transfer is ensured throughout the whole Tx coverage area. The article introduces a novel method to detect the position and orientation of the receiver only from the Tx-side measurements. The proposed solution is experimentally verified in a laboratory prototype, and the experimental results show dc-to-dc efficiency of 91% with only 1% variation in most of the Rx positions.

Construction of efficient electrochemiluminescence resonance energy transfer sensor based on SnO2/SnS2QDs-Ru@IRMOF-3 composite for sensitive detection of procalcitonin.

An efficient electrochemiluminescence resonance energy transfer (ECL-RET) method is proposed which combines the luminescent materials of tris(4,4'-dicarboxylicacid-2,2'-bipyridyl) ruthenium(II) (energy donor) and tin dioxide and tin disulfide quantum dots (SnO2/SnS2QDs) (energy acceptor) into the isoreticular metal - organic framework-3 (IRMOF-3) material to form a composite. In this mode, the distance between the energy donor and the acceptor was greatly shortened, reducing the energy loss, and thereby effectively improving RET efficiency and further significantly improving the ECL signal. The obtained composite (SnO2/SnS2QDs-Ru@IRMOF-3) was combined with sandwich immunoreaction to construct an ECL immunosensor for the sensitive detection of procalcitonin (PCT). Under the optimized experimental conditions with a working potential of - 1.48V (vs Ag/AgCl), the proposed PCT biosensor exhibited a linear concentration range of 1 × 10-4-200ngmL-1, with a detection limit of 0.029pgmL-1 (S/N = 3). The biosensor was used to detect PCT in actual samples. The biosensor has broad application prospects in biological analysis and clinical diagnosis due to its high sensitivity, good selectivity, and good stability.

A Kalman filter-based prediction strategy for multiobjective multitasking optimization

Multiobjective multitasking optimization (MO-MTO) can solve multiple optimization tasks simultaneously through knowledge transfer across tasks. However, how to design an efficient knowledge transfer method is the main challenge. Keeping this in mind, this paper proposes an evolutionary multitasking algorithm based on Kalman filter prediction strategy. Specifically, the incremental support vector machine classifier is used to find valuable solutions. Moreover, the Kalman filter prediction strategy is designed to utilize valuable solutions and historical evolutionary information to estimate the predictive solutions. Finally, the scoring scheme is constructed to adaptively select valuable solutions and predictive solutions as transfer knowledge. Experimental results on three MO-MTO test suites demonstrate that the proposed algorithm can achieve competitive performance.

A viral toolbox for conditional and transneuronal gene expression in zebrafish.

The zebrafish is an important model in systems neuroscience but viral tools to dissect the structure and function of neuronal circuitry are not established. We developed methods for efficient gene transfer and retrograde tracing in adult and larval zebrafish by herpes simplex viruses (HSV1). HSV1 was combined with the Gal4/UAS system to target cell types with high spatial, temporal, and molecular specificity. We also established methods for efficient transneuronal tracing by modified rabies viruses in zebrafish. We demonstrate that HSV1 and rabies viruses can be used to visualize and manipulate genetically or anatomically identified neurons within and across different brain areas of adult and larval zebrafish. An expandable library of viruses is provided to express fluorescent proteins, calcium indicators, optogenetic probes, toxins and other molecular tools. This toolbox creates new opportunities to interrogate neuronal circuits in zebrafish through combinations of genetic and viral approaches.

Current advances and challenges for direct interspecies electron transfer in anaerobic digestion of waste activated sludge

To realize energy self-sufficiency demand is a key component of carbon–neutral goal of wastewater treatment plants (WWTPs). Waste activated sludge (WAS), as the by-product of WWTPs, is produced in large quantities. Considering that WAS is a collection of organics, anaerobic digestion (AD) is a promising technology for methane recovery from WAS. However, conventional interspecies hydrogen transfer is vulnerable to environment changes, which can lead to instability or failure of AD. The recent finding of direct interspecies electron transfer (DIET) provides an alternative strategy to promote both the methane production potential and rate of WAS through an efficient and stable electron transfer method. This review highlights the current advances in relevant AD-based DIET for methane production from WAS, including the pathways and advantages for establishing DIET in the AD of WAS, and concludes with the current challenges in theory and application. The three main strategies for establishing DIET are conductive e-pili, conductive materials, and external voltage. These strategies not only present the advantages of shortening the lag phase and promoting the potential and rate of methane production but can also enhance intermediate degradation and provide buffering effects to inhibitors. Additionally, the role and function of microbial community structures can achieve directional regulation. Based on recent findings, theory shortages include unlocking syntrophic partners, disclosing cellular structure features, and exploring sophisticated models, while sustainable pretreatment strategies, applicable technical equipments, and comprehensive assessments may potentially limit DIET in engineering applications. This review aims to provide a comprehensive platform for establishing DIET in the AD of WAS and the carbon–neutral goal of WWTPs.

Free Difluorobis(pentafluoroethyl)phosphoranide Ion and Its Ligand Properties.

In this contribution, we report on the "free" [P(C2F5)2F2]- ion and its ligand properties in transition metal complex chemistry. For this purpose, Ag[P(C2F5)2F2] was treated with [{(Et2N)3P═N}3P═NHC(CH3)3]Cl ([EtP4H]Cl) to yield [EtP4H][P(C2F5)2F2], featuring a weakly coordinating phosphazenium cation. Due to the weak interaction between the cation and anion, the [P(C2F5)2F2]- ion meets the so-called pseudo-gas-phase conditions. To determine the Tolman electronic parameter, [EtP4H][Ni(CO)3{P(C2F5)2F2}] was prepared from [EtP4H][P(C2F5)2F2] and [Ni(CO)4], facilitating the classification of the P(C2F5)2F2 moiety as a moderately π-acidic ligand. By treatment of [EtP4H][P(C2F5)2F2] with [AuCl(tht)], the neutral tetrahydrothiophene ligand was substituted by the phosphoranide ion, yielding [EtP4H][AuCl{P(C2F5)2F2}]. When Ag[P(C2F5)2F2] was treated with [AuCl(tht)], on the other hand, the chloride was substituted. Transmetalation reactions of this type proved to be an efficient transfer method of the P(C2F5)2F2 moiety, as further demonstrated by the reactions of Ag[P(C2F5)2F2] with [FeCl(CO)2Cp], [FeCl(CO)2Cp*], and [PdCl2(NCMe)2]. Surprisingly, P(C2F5)2F demonstrated fluorinating abilities toward [FeCl(CO)2Cp], [FeCl(CO)2Cp*], [AuCl(tht)], and [PdCl2(NCMe)2]. Apparently, fluorido transition metal complexes were generated in situ under the formation of P(C2F5)2Cl. The fluorido iron and palladium complexes transfer their fluoride ions onto P(C2F5)2F, yielding the respective phosphoranido complexes, featuring the P(C2F5)2F2 moiety.

A DNA vaccine candidate delivered by an electroacupuncture machine provides protective immunity against SARS-CoV-2 infection

A major challenge in the use of DNA vaccines is efficient DNA delivery in vivo. Establishing a safe and efficient electric transfer method is the key to developing rapid DNA vaccines against emerging infectious diseases. To overcome the complexity of designing new electric transfer machines for DNA delivery, a clinically approved electric transfer machine could be considered as an alternative. Here, we report an electroacupuncture machine-based method for DNA vaccine delivery after intramuscular injection of the COVID-19 DNA vaccine. The S gene of SARS-CoV-2 in the pVAX1 plasmid (pSARS2-S) was used as an antigen in this study. We optimized the clinically used electroacupuncture machine settings for efficient induction of the neutralizing antibody titer after intramuscular injection of pSARS2-S in mice. We found that pSARS2-S immunization at 40 Vpp for 3–5 s could induce high neutralizing antibody titers and Th1-biased immune responses. IFN-γ/TNF-α-secreting CD4+ and CD8+ T cells were also observed in the DNA vaccination group but not in the recombinant protein vaccination group. T-cell epitope mapping shows that the major reactive epitopes were located in the N-terminal domain (a.a. 261–285) and receptor-binding domain (a.a. 352–363). Importantly, pSARS2-S immunization in hamsters could induce protective immunity against SARS-CoV-2 challenge in vivo. In the preclinical toxicology study, blood biochemistry, hematology, and DNA persistence analysis reveal that the DNA delivery method is safe. Furthermore, the raised antisera could also cross-neutralize different variants of concern. These findings suggest that DNA vaccination using an electroacupuncture machine is feasible for use in humans in the future.

A non-destructive and efficient transfer method for preparing 2D materials samples for transmission electron microscopy study

Studying two-dimensional (2D) materials using transmission electron microscopy (TEM) is necessary and very important in many aspects. However, some 2D materials are not resistant to acids or alkalis, which are widely used in normal wet transfer techniques to transfer the exfoliated 2D nanosheets onto the TEM grids. On the other hand, dry stamping method can damage the holey carbon film on the TEM grids. In this article, we present a non-destructive, efficient, and widely applicable transfer method for preparing the TEM samples of the exfoliated 2D materials. Our method only uses the heat-release tape, PMMA, and blue Nitto tape. Neither acid nor alkali is involved in our method, therefore, impurities and damage can be avoided to the greatest extent. The method is also very efficient and can be accomplished in less than 30 min after the exfoliation of the 2D materials. This method is particularly useful for preparing the TEM samples of the 2D materials that are not resistant to acids and alkalis. The present method is also applicable to various 2D materials and various substrates.

Dynamic Deep Genomics Sequence Encoder for Managed File Transfer

The standard communication protocols transfer big data over the internet. However, the challenge lies while sharing the massive amount of genomics data quickly over limited bandwidth networks. Managed File Transfer (MFT) that uses File Transfer Protocol Secure (FTPS) or Secure Shell File Transfer Protocol (SFTP) is a scalable and secure alternative for the purpose. This paper proposes a framework consisting of a Variable-length Genomic Binary Encoding (VGBE) scheme and a hybrid Gated Recurrent Unit-Convolutional Neural Network model (GRU-CNN). The Method exploits Managed File Transfer to reduce the bit size before transmission and increases the bit rate during the transmission of genomics data. Consequently, the method ensures a minimum number of bits per word and less latency. The methodology is tested on various communication protocols. It is validated in terms of performance metrics viz. transfer rate and the size of transferred data using diverse benchmark datasets such as protein sequences and human reference genome taken from the University of California Santa Cruz (UCSC) and National Center for Biotechnology Information (NCBI), respectively. Furthermore, simulation and implementation results show that the model is 98% faster, has 96% less data size, and is more secure than standard communication protocols. Thus, the proposed method is an efficient and secure genomics data transfer method using deep learning techniques.

Experimental study on liquid nitrogen flash evaporation spray on super-hydrophilic microstructured surface

Flash evaporation spray is an efficient heat transfer method. Changes in the microstructure and wettability of the cooling surface have important effects on its heat transfer. In this paper, four kinds of cooling surfaces, including a smooth copper surface, a square-column microstructured surface, a superhydrophilic smooth surface, and a superhydrophilic square-column surface, were prepared by chemical corrosion and laser etching. Using liquid nitrogen as the cooling medium, we conducted transient flash evaporation spray experiments on these four types of cooling surfaces. The experimental results show that surface superhydrophilic treatment can substantially enhance the flash evaporation spray of liquid nitrogen. It can more than double the cooling rate for both smooth copper surfaces and square-column microstructured surfaces. In addition, the combination of a microcolumn structure and superhydrophilicity on the cooling surface can provide double reinforcement for the liquid nitrogen flash evaporation spray. Its average cooling rate can reach 131,046 °C/min, and the maximum heat flux is 173 W/cm2. This study sheds some lights on heat transfer mechanism of superhydrophilic microstructure on the flash evaporation spray and contributes to the development of a new method for cell vitrification.

Numerical and experimental investigation of a solar absorber extension tube with turbulators for upgrading the performance of a solar dryer

PurposeDuring the past several years, research and studies in the field of solar energy have been continuously increased. One of the substantial applications of solar energy is related to industrial utilization for the drying process by efficient heat transfer methods. This study aims to upgrade the overall performance of an indirect solar dryer using a solar absorber extension tube (SET) equipped with ball-type turbulators.Design/methodology/approachIn this work, three various SETs including hollow (SET Type 1), 6-balls (SET Type 2) and 10-balls (SET Type 3), have been simulated using Fluent software to evaluate heat transfer characteristics and flow structure along the air passage. Then, the modified solar drying system has been manufactured and tested at different configurations.FindingsThe findings indicated that adding a SET improved the performance notably. According to the results, using turbulators in the tube has a positive effect on heat transfer. The highest overall thermal efficiency was found in the range of 51.47%–64.71% for the system with SET Type 3. The maximum efficiency increment of the system was found as 19% with the use of SET. Also, the average specific moisture extraction rate, which is a significant factor to survey the effectiveness of the dehumidification system was found between 0.20 and 0.38 kg kWh−1.Originality/valueIn the present study, a novel SET has been developed to upgrade the performance of the solar dehumidifier. This new approach makes it possible to improve both thermal and drying performances.

An Optimal Design Method for Improving the Efficiency of Ultrasonic Wireless Power Transmission during Communication.

Due to the excellent directivity, strong penetrability, and no electromagnetic shielding effect, ultrasonic waves have good potential for wireless energy transmission and information transfer inside and outside of sealed metal devices. However, traditional ultrasonic based energy transmission methods usually result in considerable energy consumption because of the impedance mismatch during the impedance modulation of the communication. This paper presents an optimal design method for efficient energy transfer during ultrasonic communication. The channel equivalent circuit model is established by only using the acoustic-electric channel scattering parameters. According to the equivalent circuit model, the channel impedance matches with a weak mismatch state is performed during the communication. In this way, the impedance modulation effect is ensured with a lower decrease in the energy transmission efficiency. Finally, the simultaneous energy transmission and impedance modulation are carried out through the 11 mm thick 304 stainless steel plate. The transmission power is 37.86 W with a transmission efficiency of 45.75%, and the modulation rate is 10 Kbps. Compared with the traditional methods, our proposed energy transmission efficiency is increased by 17.62%. The results verify the proposed method’s effectiveness and the high accuracy of the model. The proposed method has great engineering applications and broad prospects in condition monitoring of metallic environments.

Determination of the coincidence summing factor by Monte Carlo method using MCNP–CP and PENNUC codes

In gamma spectrometry, the quantitative information about the composition of elements present in the experimental samples can be obtained from the efficiency calibration curve, the radioactivity, and the gamma emission intensity of the radioactive. The efficiency of the detector is often affected by the coincidence summing effect. The correction of the coincidence summing factors can be done through the software based on the efficiency transfer method or Monte Carlo simulation. In this study, two Monte Carlo simulation software, MCNP‒CP and PENNUC, were applied to calculate the coincidence summing factors of four radioactive 22Na, 60Co, 133Ba, and 134Cs by the simulation method. The calculated models from the benchmark with two types of detectors of n-type and p-type, using different source geometries such as point source, water, soil, and filter samples, were used. This study aimed to validate the spectral response as well as to compare the coincidence summing factors between MCNP‒CP and PENNUC. The results showed that the coincidence summing factors calculated by two simulation software gave a good agreement with an average relative deviation of less than 2%. The coincidence summing factors calculated by two simulation programs were verified by the statistical T-test with a linear correlation value of rxy = 0.995.