Contactless Environment Research Articles

Contactless weighing method based on deep learning and acoustic levitation

Abstract Acoustic weighing is a promising contactless method for screening the mass of micro-nano objects as it avoids contact contamination and losses. Existing acoustic weighing methods determine the mass of an object by detecting its oscillation trajectory with a laser sensor. However, this method suffers from several limitations, such as short measurement distance, poor accuracy in measuring transparent objects, and inducing damage to photosensitive samples. To solve these issues, this work proposes a contactless weighing method based on location-aware neural network (LANet) and acoustic levitation. The proposed LANet is a deep learning-based image processing method that detects object bit oscillation trajectories completely contactless, regardless of the color, shape, and oscillation distance of the levitated object. We employ a cross-stage aggregation module and cross-mixed feature pyramid strategy to build LANet network depth for enhanced feature extraction. In addition, to create a contactless environment, we built an acoustic levitation system, which drives the oscillation of objects. Finally, we verified the accuracy and effectiveness of the method. The results show that the proposed network can accurately detect the oscillation trajectories of various objects with high detection performance, even for small objects in low-contrast backgrounds. Meanwhile, the proposed method can accurately measure the mass of objects with a percentage error of no more than 7.83%.

Intelligent automated monitoring system using video surveillance based recognition

The current pandemic situation makes it necessary to work in a contactless environment where human intervention is minimalized at most. Video surveillance is an important security asset for monitoring purposes at banks, department stores, highways, and crowded public places. With improved technology and a growing population, surveillance is becoming a key area in research. The best utilization of technology for surveillance is the focus area today. In recent times, object detection has come to the frontline as an important application in the field of Deep Learning. Unlike traditional methods, object detection in deep learning is characterized by its ability to learn features and depict the same. The proposed system aims at creating a platform that reduces/eliminates human intervention for monitoring purposes by using a CCTV camera assisted automated monitoring system. There is scope for automation, which would perform object detection and automatically open the door/gate when the same has been recognized. Here, CNN models are to be used for real-time object detection via the CCTV camera.

JomMobileKey: Opening Business Sense During Covid19 Pandemic

Security remains a key issue in the hospitality industry mostly due to incidents of theft and crime as previously reported. This study aims to design a system that enables hotel guests to access hotel room without using a physical card. To promote high-security attributes, NFC (Near-field communication) technology as an access system by implementing applications containing emulated smart key for specific authentication access is used. The Host-Card Emulation HCE enables cost-effectiveness profit and initiates defense system in the pandemic era. The proposed system was evaluated by statistical and analytical analysis with hotel staff and managers in two different hotels located in Malaysia. The findings show the proposed system could replace physical cards, enhance security, and promote a contactless environment. More test cases at different locations are required to further validate the proposed system. The proposed system can be implemented in other industries in the future.

Analysis of the Effectiveness of SOFTWARE LIBERAL EDUCATION in a Non-Face-To-Face Environment

Purpose: Based on the previous studies, in this study, and in order to confirm the effect of the university s software liberal education in a contactless environment, as for the specific factors influencing the satisfaction of learning and academic achievement, the quality of classroom instruction, motivation for learning, convenience of time, and the immersion for learning were derived as the major factors according to the details of classroom instruction and learning contents. In this study, it is intended to examine the effectiveness of the university s basic software education in a contactless environment via the relationship between such factors and their influence on the satisfaction of learning and academic achievement. Method: In order to validate the effect of the university s basic software education in a contactless environment, this study has analyzed the differences between the subjects general characteristics, quality of classroom instruction, motivation for learning, convenience of time, immersion for learning, satisfaction of learning, and academic achievement by using the descriptive statistics of error, percentage, mean and standard deviation. The correlation of the quality of classroom instruction, motivation for learning, convenience of time, immersion for learning, satisfaction of learning, and academic achievement was analyzed by the Pearson s correlation, and the effect of each factor on the satisfaction of learning and academic achievement was analyzed by performing the multiple regression. Results: It was evaluated that the satisfaction of learning enhanced as the quality of classroom instruction improved and the immersion for learning worked well. It was also evaluated that, as the high quality details of classroom instruction and learning contents were provided, and the higher the motivation for learning, the higher the academic achievement, and the higher the convenience of time, the lower the academic achievement. Even in a contactless environment, the quality of classroom instruction is very important, and it may be said that it is the variable which has the largest influence on the effectiveness of the classroom instruction. Conclusion: It was confirmed that it has had a positive effect on the students satisfaction of learning and academic achievement by causing high quality classroom instruction, motivation for learning, and active immersion for learning in a contactless environment. Based on such results of this study, it is expected that assistance may be provided for developing and promoting various online education programs.

Real-Time In situ XRD Study of Simvastatin Crystallization in Levitated Droplets

Simvastatin (SV) is an important active pharmaceutical ingredient (API) for treatment of hyperlipidemias, which is known to exist in different crystalline and amorphous phases. It is, therefore, an interesting model to investigate how the outcome of evaporative crystallization in the contactless environment of an acoustically levitated droplet may be influenced by key experimental conditions, such as temperature, solvent properties (e.g., polarity and hygroscopicity), and dynamics of the evaporation process. Here, we describe a real-time and in situ study of simvastatin evaporative crystallization from droplets of three solvents that differ in volatility, polarity, and protic character (acetone, ethanol, and ethyl acetate). The droplet monitorization relied on synchrotron X-ray diffraction (XRD), Raman spectroscopy, imaging, and thermographic analysis. A pronounced solvent-dependent behavior was observed. In ethanol, a simvastatin amorphous gel-like material was produced, which showed no tendency for crystallization over time; in ethyl acetate, a glassy material was formed, which crystallized on storage over a two-week period to yield simvastatin form I; and in acetone, form I crystallized upon solvent evaporation without any evident presence of a stable amorphous intermediate. The XRD and Raman results further suggested that the persistent amorphous phase obtained from ethanol and the amorphous precrystallization intermediate formed in ethyl acetate were similar. Thermographic analysis indicated that the evaporation process was accompanied by a considerable temperature decrease of the droplet surface, whose magnitude and rate correlated with the solvent volatility (acetone > ethyl acetate > ethanol). The combined thermographic and XRD results also suggested that, as the cooling effect increased, so did the amount of residual water (most likely captured from the atmosphere) remaining in the droplet after the organic solvent was lost. Finally, the interpretation of the water fingerprint in the XRD time profiles was aided by molecular dynamics simulations, which also provided insights into the possible role of H2O as an antisolvent that facilitates simvastatin crystallization.

State of the Art of Anti-Screen Capture Protection Techniques

The transition toward a contactless society has been rapidly progressing owing to the recent COVID-19 pandemic. As a result, the IT environment of organizations and enterprises is changing rapidly;in particular, data security is expanding to the private sector. To adapt to these changes, organizations and companies have started to securely transfer confidential data to residential PCs and personally owned devices of employees working from home or from other locations. Therefore, organizations and companies are introducing streaming data services, such as the virtual desktop infrastructure (VDI) or cloud services, to securely connect internal and external networks. These methods have the advantage of providing data without the need to download to a third terminal;however, while the data are being streamed, attacks such as screen shooting or capturing are performed. Therefore, there is an increasing interest in prevention techniques against screen capture threats that may occur in a contactless environment. In this study, we analyze possible screen capture methods in a PC and a mobile phone environment and present techniques that can protect the screens against specific attack methods. The detection and defense for screen capture of PC applications on Windows OS and Mac OS could be solved with a single agent using our proposed techniques. Screen capture of mobile devices can be prevented by applying our proposed techniques on Android and iOS. © 2021 KSII.

The Transformation of the Advertising Industry in the ‘Un-tact’ Digital Technology Era

The advent of the “un-tact 2.0 era,” described as a “new normal non-face-to-face social relationship,” accelerates the transformation of the living paradigm as a fully digital mediated social relationship. The emergence of these new forms of digital behaviors and mediated relationships significantly influences the industry prospect and consumers’ individual lives. Advertising has played a decisive role in moving the formation forces of society, creating a dynamic flow of the capitalist system across races and geographical boundaries. Its role will become more fundamental in the physical contactless environment due to the COVID-19 outbreak. Accordingly, advertising has changed and modified its shape and meaning throughout history to adapt to the dynamic external environment. In this article, we illustrated four primary stages of the evolution in the advertising industry from simple advertising to convergence of advertising. Finally, we also identified the challenges of the present advertising industry and the paradigm transformation of “un-tact 2.0” with various related examples.

Novel Method for Surface Tension Measurement: the Drop-Bounce Method

The surface tension of liquids at high temperatures is generally measured with the well-established oscillating drop method in a contactless environment. However, technical difficulties in surface tension measurements make it hard to apply the oscillating drop method to the aerodynamic levitation (ADL) system, the most reliable levitation technique for liquids with low electrical conductivity. In this study, we developed a novel drop–bounce method that can be used within an ADL system to measure the surface tension of liquids. A levitated molten sample was first dropped onto an inert substrate through a splittable nozzle. The rebounded sample’s oscillatory motion behaved as it would under microgravity conditions during its free-fall, and oscillations were obtained only in the l=2, m=0 mode. Fourier transformation of the oscillation pattern provided resonant frequency of the l=2, m=0 mode and enabled the calculation of the surface tension of the sample under knowledge of its mass. Furthermore, a short experimental duration of less than 50 ms significantly reduced the possibility of surface evaporation in the sample. Our measured surface tension data from 1354 K to 1827 K for gold exhibited a standard deviation of 13.4 mJ/m2 and were consistent with the data published by Egry et al. under microgravity conditions, with a maximum deviation of 1.5% between the two fitted linear equations.

Insights on drying and precipitation dynamics of respiratory droplets from the perspective of COVID-19.

We isolate a nano-colloidal droplet of surrogate mucosalivary fluid to gain fundamental insights into airborne nuclei’s infectivity and viral load distribution during the COVID-19 pandemic. The salt-water solution containing particles at reported viral loads is acoustically trapped in a contactless environment to emulate the drying, flow, and precipitation dynamics of real airborne droplets. Similar experiments validate observations with the surrogate fluid with samples of human saliva samples from a healthy subject. A unique feature emerges regarding the final crystallite dimension; it is always 20%–30% of the initial droplet diameter for different sizes and ambient conditions. Airborne-precipitates nearly enclose the viral load within its bulk while the substrate precipitates exhibit a high percentage (∼80–90%) of exposed virions (depending on the surface). This work demonstrates the leveraging of an inert nano-colloidal system to gain insights into an equivalent biological system.

Dual-Balance Electrodynamic Trap as a Microanalytical Tool for Identifying Gel Transitions and Viscous Properties of Levitated Aerosol Particles.

The formation of gelatinous networks within an aerosol particle significantly alters the physicochemical properties of the aerosol material. Existing techniques for studying gel transitions rely on bulk rheometry, which is limited by contact with the sample, or microrheological techniques such as holographic optical tweezers, which rely on expensive equipment and high-powered lasers that can degrade light-absorbing aerosol. Here, we present a new technique to probe the microrheological characteristics of aerosol particles and explore gel formation under atmospheric conditions in a contactless environment without the need for high-power light sources. In a dual-balance quadrupole electrodynamic balance, levitated droplets of opposite polarity are trapped and equilibrated at fixed relative humidity (RH) and then subsequently merged, and the physical characteristics of the merged droplets are monitored as a function of time and RH using imaging techniques. By comparing the RH-dependent characteristics of MgSO4 (known to undergo a gel transition) to glucose and sucrose (known to remain as viscous Newtonian fluids) under fixed equilibration time scales, we demonstrate that gel phase transitions can be identified in aerosol particles, with MgSO4 abruptly transitioning to a rigid microgel at 30% RH. Further, we demonstrate this technique can be used to also measure aerosol viscosity and identify non-Newtonian fluid dynamics in model sea spray aerosol composed of NaCl, CaCl2, and sorbitol. Thus, using this experimental technique, it is possible to distinguish between aerosol compositions that form viscous Newtonian fluids and those that undergo a gel transition or form non-Newtonian fluids. This technique offers a simple and cost-effective analytical tool for probing gel transitions outside of bulk solubility limits, with relevant applications ranging from atmospheric science to microengineering of soft matter materials.

Masked SIFT with align‐based refinement for contactless palmprint recognition

Contactless palmprint is considered more user convenient than other biometrics due to its acquisition simplicity and less-private nature. Many challenges arise which affect the performance of common contact-based methods when applied to a contactless environment. For example, pose and illumination variations affect the layout and visibility of palm lines. This study proposes a SIFT-based method with three main modifications from the traditional SIFT. First, the palm regions with no significant lines/wrinkles are masked out to reduce the false features. A region with multi-lines is then described by multi-descriptors rather than a single one. Second, only query and target keypoints with small rotation difference are compared together, instead of comparing them all. This speed-up the comparison and enhance the accuracy, versus SIFT, by reducing the wrong matches. Third, an align-based refinement is applied to filter out the incorrect matches. The method is tested on three contactless hand databases; IITD, GPDS and Sfax-Miracl. It achieves a verification equal error rate of 0.72, 0.84 and 1.14% and a correct identification rate of 98.9, 99 and 98.9% on each database, respectively. These results are significantly better than the state-of-art methods on the same databases by 1.9% for verification and 3.2% for identification.

How boiling happens in nanofuel droplets

We report detailed analyses of evaporation and atomisation characteristics of nanofuel droplets in a contactless environment (acoustic levitation) under external radiative heating. Two base fuels, ethanol and n-dodecane with a significant difference in their respective vapour-pressures, are considered. Nanoparticles (NPs) of cerium oxides (CeO2) are utilised as nano-additives at a dilute particle loading rate (PLR) of 0%-0.5% by weight. Pure ethanol droplets vaporise at a faster rate than pure dodecane droplets and do not exhibit any secondary atomisation. However, pure dodecane droplets exhibit two modes of secondary breakup; Kelvin-Helmholtz instability induced stripping and catastrophic breakup beyond a certain threshold value of the initial droplet size. Nanofuel droplets of ethanol neither exhibit any significant change in the vaporisation rate nor exhibit secondary atomization. Contrarily, dodecane-based nanofuels show enhanced vaporisation due to heat absorption by nanoparticles and consequently different modes of secondary breakup. Interestingly, dodecane-based nanofuel droplets exhibit internal boiling induced atomization. A time scale analysis considering orthokinetic NP aggregation, evaporation lifetime, and bubble growth rate is presented to elucidate the mechanism of such internal boiling. The theoretical non-dimensional time scale (τ*) so coined is extended to estimate the minimum value of the droplet size necessary for exhibiting boiling. The analysis shows excellent agreement with the experimental observations. Furthermore, we propose a unique three-dimensional regime map to correlate the breakup modes with droplet sizes, PLR, and heating rates.

Toward Contactless Biology: Acoustophoretic DNA Transfection.

Acoustophoresis revolutionized the field of container-less manipulation of liquids and solids by enabling mixing procedures which avoid contamination and loss of reagents due to the contact with the support. While its applications to chemistry and engineering are straightforward, additional developments are needed to obtain reliable biological protocols in a contactless environment. Here, we provide a first, fundamental step towards biological reactions in air by demonstrating the acoustophoretic DNA transfection of mammalian cells. We developed an original acoustophoretic design capable of levitating, moving and mixing biological suspensions of living mammalians cells and of DNA plasmids. The precise and sequential delivery of the mixed solutions into tissue culture plates is actuated by a novel mechanism based on the controlled actuation of the acoustophoretic force. The viability of the contactless procedure is tested using a cellular model sensitive to small perturbation of neuronal differentiation pathways. Additionally, the efficiency of the transfection procedure is compared to standard, container-based methods for both single and double DNA transfection and for different cell types including adherent growing HeLa cancer cells, and low adhesion neuron-like PC12 cells. In all, this work provides a proof of principle which paves the way to the development of high-throughput acoustophoretic biological reactors.