Sensors

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15 pages, 5096 KiB

Open AccessArticle

Exploring Endothelial Expansion on a Chip

by Joanna Konopka, Dominik Kołodziejek, Magdalena Flont, Agnieszka Żuchowska, Elżbieta Jastrzębska and Zbigniew Brzózka

Sensors 2022, 22(23), 9414; https://doi.org/10.3390/s22239414 - 2 Dec 2022

Cited by 6 | Viewed by 2332

Abstract

Angiogenesis is the development of new blood vessels from the existing vasculature. Its malfunction leads to the development of cancers and cardiovascular diseases qualified by the WHO as a leading cause of death worldwide. A better understanding of mechanisms regulating physiological and pathological [...] Read more.

Angiogenesis is the development of new blood vessels from the existing vasculature. Its malfunction leads to the development of cancers and cardiovascular diseases qualified by the WHO as a leading cause of death worldwide. A better understanding of mechanisms regulating physiological and pathological angiogenesis will potentially contribute to developing more effective treatments for those urgent issues. Therefore, the main goal of the following study was to design and manufacture an angiogenesis-on-a-chip microplatform, including cylindrical microvessels created by Viscous Finger Patterning (VFP) technique and seeded with HUVECs. While optimizing the VFP procedure, we have observed that lumen’s diameter decreases with a diminution of the droplet’s volume. The influence of Vascular Endothelial Growth Factor (VEGF) with a concentration of 5, 25, 50, and 100 ng/mL on the migration of HUVECs was assessed. VEGF’s solution with concentrations varying from 5 to 50 ng/mL reveals high angiogenic potential. The spatial arrangement of cells and their morphology were visualized by fluorescence and confocal microscopy. Migration of HUVECs toward loaded angiogenic stimuli has been initiated after overnight incubation. This research is the basis for developing more complex vascularized multi-organ-on-a-chip microsystems that could potentially be used for drug screening. Full article

(This article belongs to the Special Issue I3S 2022 Selected Papers)

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15 pages, 15876 KiB

Open AccessArticle

Sensor Actuator Network for In Situ Studies of Antarctic Plants Physiology

by Krzysztof Herman, Mauricio Montanares, Leon Bravo and Joanna Plenzler

Sensors 2022, 22(22), 8944; https://doi.org/10.3390/s22228944 - 18 Nov 2022

Viewed by 2136

Abstract

This article documents a custom sensor–actuator network designed and implemented as a part of experimental setup, where a long-term phenological response of antarctic plants is studied. The first part of our work presents the context of the study, reports experimental methods used in [...] Read more.

This article documents a custom sensor–actuator network designed and implemented as a part of experimental setup, where a long-term phenological response of antarctic plants is studied. The first part of our work presents the context of the study, reports experimental methods used in antarctic plant field studies, and characterizes the environmental conditions and logistics facilities available on the measurement spot. After contextualization of the research, we present, in detail, both the network itself and some results obtained during the Antarctic summer seasons between 2019 and 2022 on the King George Island, South Shetlands. The results collected with our network and correlated with selected data registered with a reference automatic meteorological station reveal the thermal plants response. The groups of plants individuals, which were actively warmed using thermal actuators, show the nighttime temperature difference, in reference to the air temperature, of 5

^{\circ}

C, which complements the daytime difference caused by the passive method of open top chamber (OTC) used in previous studies carried out in the same localization. Full article

(This article belongs to the Special Issue I3S 2022 Selected Papers)

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7 pages, 4511 KiB

Open AccessArticle

Development of Three-Axis Fibre-Optic Seismograph for Direct and Autonomous Monitoring of Rotational Events with Perspective of Historical Review

by Anna T. Kurzych, Leszek R. Jaroszewicz and Jerzy K. Kowalski

Sensors 2022, 22(22), 8902; https://doi.org/10.3390/s22228902 - 17 Nov 2022

Cited by 4 | Viewed by 1654

Abstract

The paper presents historical perspective of fibre-optic seismographs designed and constructed at the Institute of Applied Physics at Military University of Technology, Poland based on the so-called minimum configuration of fibre-optic gyroscope. The briefly presented history, which originated in the 1998 by the [...] Read more.

The paper presents historical perspective of fibre-optic seismographs designed and constructed at the Institute of Applied Physics at Military University of Technology, Poland based on the so-called minimum configuration of fibre-optic gyroscope. The briefly presented history, which originated in the 1998 by the system named GS-13P, laid solid foundations for the construction of a three-axis fibre-optic seismograph. The presented system meets all technical requirements of rotational seismology in terms of measurement parameters (measuring range from 10⁻⁸ rad/s to several rad/s and frequency from 0.01 Hz to 100 Hz) and utility features (mobility, autonomy, power independence, environmental stability). The presented device provides universal application both for research in engineering applications (high buildings, chimneys, wind towers) as well as in seismological research. Full article

(This article belongs to the Special Issue I3S 2022 Selected Papers)

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12 pages, 2270 KiB

Open AccessArticle

Self-Assembling Graphene Layers for Electrochemical Sensors Printed in a Single Screen-Printing Process

by Andrzej Pepłowski, Filip Budny, Marta Jarczewska, Sandra Lepak-Kuc, Łucja Dybowska-Sarapuk, Dominik Baraniecki, Piotr Walter, Elżbieta Malinowska and Małgorzata Jakubowska

Sensors 2022, 22(22), 8836; https://doi.org/10.3390/s22228836 - 15 Nov 2022

Cited by 1 | Viewed by 1897

Abstract

This article reports findings on screen-printed electrodes employed in microfluidic diagnostic devices. The research described includes developing a series of graphene- and other carbon form-based printing pastes compared to their rheological parameters, such as viscosity in static and shear-thinning conditions, yield stress, and [...] Read more.

This article reports findings on screen-printed electrodes employed in microfluidic diagnostic devices. The research described includes developing a series of graphene- and other carbon form-based printing pastes compared to their rheological parameters, such as viscosity in static and shear-thinning conditions, yield stress, and shear rate required for thinning. In addition, the morphology, electrical conductivity, and electrochemical properties of the electrodes, printed with the examined pastes, were investigated. Correlation analysis was performed between all measured parameters for six electrode materials, yielding highly significant (p-value between 0.002 and 0.017) correlations between electron transfer resistance (Ret), redox peak separation, and static viscosity and thinning shear-rate threshold. The observed more electrochemically accessible surface was explained according to the fluid mechanics of heterophase suspensions. Under changing shear stress, the agglomeration enhanced by the graphene nanoplatelets’ interparticle affinity led to phase separation. Less viscous pastes were thinned to a lesser degree, allowing non-permanent clusters to de-agglomerate. Thus, the breaking of temporary agglomerates yielded an unblocked electrode surface. Since the mechanism of phase ordering through agglomeration and de-agglomeration is affected by the pastes’ rheology and stress during the printing process and requires no further treatment, it can be appropriately labeled as a self-assembling electrode material. Full article

(This article belongs to the Special Issue I3S 2022 Selected Papers)

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16 pages, 3756 KiB

Open AccessArticle

A Study of the Radiation Tolerance and Timing Properties of 3D Diamond Detectors

by Lucio Anderlini, Marco Bellini, Vladimir Cindro, Chiara Corsi, Keida Kanxheri, Stefano Lagomarsino, Chiara Lucarelli, Arianna Morozzi, Giovanni Passaleva, Daniele Passeri, Silvio Sciortino, Leonello Servoli and Michele Veltri

Sensors 2022, 22(22), 8722; https://doi.org/10.3390/s22228722 - 11 Nov 2022

Cited by 4 | Viewed by 1889

Abstract

We present a study on the radiation tolerance and timing properties of 3D diamond detectors fabricated by laser engineering on synthetic Chemical Vapor Deposited (CVD) plates. We evaluated the radiation hardness of the sensors using Charge Collection Efficiency (CCE) measurements after neutron fluences [...] Read more.

We present a study on the radiation tolerance and timing properties of 3D diamond detectors fabricated by laser engineering on synthetic Chemical Vapor Deposited (CVD) plates. We evaluated the radiation hardness of the sensors using Charge Collection Efficiency (CCE) measurements after neutron fluences up to 10

^{16}

n/cm

^{2}

(1 MeV equivalent.) The radiation tolerance is significantly higher when moving from standard planar architecture to 3D architecture and increases with the increasing density of the columnar electrodes. Also, the maximum applicable bias voltage before electric breakdown increases significantly after high fluence irradiation, possibly due to the passivation of defects. The experimental analysis allowed us to predict the performance of the devices at higher fluence levels, well in the range of 10

^{16}

n/cm

^{2}

. We summarize the recent results on the time resolution measurements of our test sensors after optimization of the laser fabrication process and outline future activity in developing pixel tracking systems for high luminosity particle physics experiments. Full article

(This article belongs to the Special Issue I3S 2022 Selected Papers)

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13 pages, 3741 KiB

Open AccessArticle

Multispectral Portable Fibre-Optic Reflectometer for the Classification of the Origin of Chicken Eggshells in the Case of Mycoplasma synoviae Infections

by Anna Pakuła, Wojciech Żołnowski, Sławomir Paśko, Olimpia Kursa, Paweł Marć and Leszek R. Jaroszewicz

Sensors 2022, 22(22), 8690; https://doi.org/10.3390/s22228690 - 10 Nov 2022

Cited by 1 | Viewed by 1527

Abstract

The proper classification of the origins of food products is a crucial issue all over the world nowadays. In this paper, the authors present a device—a multispectral portable fibre-optic reflectometer and signal processing patch—together with a machine-learning algorithm for the classification of the [...] Read more.

The proper classification of the origins of food products is a crucial issue all over the world nowadays. In this paper, the authors present a device—a multispectral portable fibre-optic reflectometer and signal processing patch—together with a machine-learning algorithm for the classification of the origins of chicken eggshells in the case of Mycoplasma synoviae infection. The sensor device was developed based on previous studies with a continuous spectrum in transmittance and selected spectral lines in reflectance. In the described case, the sensor is based on the integration of reflected spectral data from short spectral bands from the VIS and NIR region, which are produced by single-colour LEDs and introduced to the sample via a fibre bundle. The measurement is carried out in a sequence, and the reflected signal is pre-processed to be put in the machine learning algorithm. The support vector machine algorithm is used together with three different types of data normalization. The obtained results of the F-score factor for classification of the origins of samples show that the percentages of eggs coming from Mycoplasma synoviae infected hens are up to 87% for white and 96% for brown eggshells. Full article

(This article belongs to the Special Issue I3S 2022 Selected Papers)

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13 pages, 6004 KiB

Open AccessArticle

Post-Processing of Raw Data Recorded Continuously Using a FORS—Fibre-Optic Rotational Seismograph

by Bartosz Sakowicz, Marek Kamiński, Michał Dudek, Anna T. Kurzych and Leszek R. Jaroszewicz

Sensors 2022, 22(22), 8673; https://doi.org/10.3390/s22228673 - 10 Nov 2022

Cited by 1 | Viewed by 1637

Abstract

Modern optoelectronic devices use the advantage of digital systems for data processing aimed at delivering reliable information. However, since commonly used DACs have limited accuracy, some artefacts can be observed in data streams, especially in systems designed for continuous, long-term process monitoring. In [...] Read more.

Modern optoelectronic devices use the advantage of digital systems for data processing aimed at delivering reliable information. However, since commonly used DACs have limited accuracy, some artefacts can be observed in data streams, especially in systems designed for continuous, long-term process monitoring. In this paper, the authors’ experience with data enhancement using a fibre-optic rotational seismograph (FORS) operating in a closed-loop mode is presented and discussed. Generally, two kinds of enhancement are described. The first one uses suitable filtering techniques adequate for FORS noise investigation, as well as a suitable data resampling method for transmitted data file size reduction. The second one relates to the artefacts observed during data recording in real time. The recording starting point is triggered when the detected signal exceeds a middle signal level and, therefore, the existence of artefacts generally disturbs the recording process. Although the artefacts are easily recognised by human eyes even at first sight, their automatic elimination is not so easy. In this paper, the authors propose a new concept of signal filtering to solve the above problem. Full article

(This article belongs to the Special Issue I3S 2022 Selected Papers)

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10 pages, 2388 KiB

Open AccessCommunication

Electrochemical Gene Amplification Signal Detection of Disposable Biochips Using Electrodes

by Gyo-Rim Kim, Ji-Soo Hwang, Jong-Dae Kim, Yu-Seop Kim and Chan-Young Park

Sensors 2022, 22(22), 8624; https://doi.org/10.3390/s22228624 - 9 Nov 2022

Viewed by 1564

Abstract

Real-time Polymerase Chain Reaction (RT-PCR), a molecular diagnostic technology, is spotlighted as one of the quickest and fastest diagnostic methods for the actual coronavirus (SARS-CoV-2). However, the fluorescent label-based technology of the RT-PCR technique requires expensive equipment and a sample pretreatment process for [...] Read more.

Real-time Polymerase Chain Reaction (RT-PCR), a molecular diagnostic technology, is spotlighted as one of the quickest and fastest diagnostic methods for the actual coronavirus (SARS-CoV-2). However, the fluorescent label-based technology of the RT-PCR technique requires expensive equipment and a sample pretreatment process for analysis. Therefore, this paper proposes a biochip based on Electrochemical Impedance Spectroscopy (EIS). In this paper, it was possible to see the change according to the concentration by measuring the impedance with a chip made of two electrodes with different shapes of sample DNA. Full article

(This article belongs to the Special Issue I3S 2022 Selected Papers)

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17 pages, 5924 KiB

Open AccessArticle

Compact Camera Fluorescence Detector for Parallel-Light Lens-Based Real-Time PCR System

by Seul-Bit-Na Koo, Yu-Seop Kim, Chan-Young Park and Deuk-Ju Lee

Sensors 2022, 22(21), 8575; https://doi.org/10.3390/s22218575 - 7 Nov 2022

Cited by 1 | Viewed by 2010

Abstract

The polymerase chain reaction is an important technique in biological research. However, it is time consuming and has a number of disadvantages. Therefore, real-time PCR technology that can be used in real-time monitoring has emerged, and many studies are being conducted regarding its [...] Read more.

The polymerase chain reaction is an important technique in biological research. However, it is time consuming and has a number of disadvantages. Therefore, real-time PCR technology that can be used in real-time monitoring has emerged, and many studies are being conducted regarding its use. Real-time PCR requires many optical components and imaging devices such as expensive, high-performance cameras. Therefore, its cost and assembly process are limitations to its use. Currently, due to the development of smart camera devices, small, inexpensive cameras and various lenses are being developed. In this paper, we present a Compact Camera Fluorescence Detector for use in parallel-light lens-based real-time PCR devices. The proposed system has a simple optical structure, the system cost can be reduced, and the size can be miniaturized. This system only incorporates Fresnel lenses without additional optics in order for the same field of view to be achieved for 25 tubes. In the center of the Fresnel lens, one LED and a complementary metal-oxide semiconductor camera were placed in directions that were as similar as possible. In addition, to achieve the accurate analysis of the results, image processing was used to correct them. As a result of an experiment using a reference fluorescent substance and double-distilled water, it was confirmed that stable fluorescence detection was possible. Full article

(This article belongs to the Special Issue I3S 2022 Selected Papers)

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11 pages, 4945 KiB

Open AccessArticle

The Detection of Foreign Items in Laundry Industry by Dual-Energy X-ray Transmission—Advantages and Limits

by Christine Bauer, Rebecca Wagner and Johannes Leisner

Sensors 2022, 22(21), 8248; https://doi.org/10.3390/s22218248 - 27 Oct 2022

Cited by 1 | Viewed by 1963

Abstract

Firefighters, paramedics, nursing staff, and other occupational groups are in constant need of fast and proper cleaning of their professional workwear, not only during a pandemic. Thus, laundry technology needs to become more efficient and automated. Unfortunately, some steps of the cleaning process, [...] Read more.

Firefighters, paramedics, nursing staff, and other occupational groups are in constant need of fast and proper cleaning of their professional workwear, not only during a pandemic. Thus, laundry technology needs to become more efficient and automated. Unfortunately, some steps of the cleaning process, such as finding and removing foreign items from pockets or belts, are still completed manually. This is not just time-consuming but potentially dangerous for the workers due to the hazardous nature of items such as scissors, scalpels, or syringes. Additionally, some items may damage the garments by staining or harm the laundry machines, causing malfunctions and process failure. On the one hand, these foreign items are often hidden inside the clothes, making detection very challenging with conventional superficial sensors. On the other hand, these items can be diverse and cannot be detected by metal detectors alone. X-ray transmission has proven to be a powerful tool for detecting items inside of objects. The dual-energy approach (DE-XRT) even allows obtaining quantitative information about the chemical composition of the measured materials. In this study, working garments were accompanied and filled with realistic foreign items. The potential of DE-XRT to detect those items was successfully shown. Full article

(This article belongs to the Special Issue I3S 2022 Selected Papers)

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26 pages, 8235 KiB

Open AccessArticle

FAPNET: Feature Fusion with Adaptive Patch for Flood-Water Detection and Monitoring

by MD Samiul Islam, Xinyao Sun, Zheng Wang and Irene Cheng

Sensors 2022, 22(21), 8245; https://doi.org/10.3390/s22218245 - 27 Oct 2022

Cited by 2 | Viewed by 3461

Abstract

In satellite remote sensing applications, waterbody segmentation plays an essential role in mapping and monitoring the dynamics of surface water. Satellite image segmentation—examining a relevant sensor data spectrum and identifying the regions of interests to obtain improved performance—is a fundamental step in satellite [...] Read more.

In satellite remote sensing applications, waterbody segmentation plays an essential role in mapping and monitoring the dynamics of surface water. Satellite image segmentation—examining a relevant sensor data spectrum and identifying the regions of interests to obtain improved performance—is a fundamental step in satellite data analytics. Satellite image segmentation is challenging for a number of reasons, which include cloud interference, inadequate label data, low lighting and the presence of terrain. In recent years, Convolutional Neural Networks (CNNs), combined with (satellite captured) multispectral image segmentation techniques, have led to promising advances in related research. However, ensuring sufficient image resolution, maintaining class balance to achieve prediction quality and reducing the computational overhead of the deep neural architecture are still open to research due to the sophisticated CNN hierarchical architectures. To address these issues, we propose a number of methods: a multi-channel Data-Fusion Module (DFM), Neural Adaptive Patch (NAP) augmentation algorithm and re-weight class balancing (implemented in our PHR-CB experimental setup). We integrated these techniques into our novel Fusion Adaptive Patch Network (FAPNET). Our dataset is the Sentinel-1 SAR microwave signal, used in the Microsoft Artificial Intelligence for Earth competition, so that we can compare our results with the top scores in the competition. In order to validate our approach, we designed four experimental setups and in each setup, we compared our results with the popular image segmentation models UNET, VNET, DNCNN, UNET++, U2NET, ATTUNET, FPN and LINKNET. The comparisons demonstrate that our PHR-CB setup, with class balance, generates the best performance for all models in general and our FAPNET approach outperforms relative works. FAPNET successfully detected the salient features from the satellite images. FAPNET with a MeanIoU score of 87.06% outperforms the state-of-the-art UNET, which has a score of 79.54%. In addition, FAPNET has a shorter training time than other models, comparable to that of UNET (6.77 min for 5 epochs). Qualitative analysis also reveals that our FAPNET model successfully distinguishes micro waterbodies better than existing models. FAPNET is more robust to low lighting, cloud and weather fluctuations and can also be used in RGB images. Our proposed method is lightweight, computationally inexpensive, robust and simple to deploy in industrial applications. Our research findings show that flood-water mapping is more accurate when using SAR signals than RGB images. Our FAPNET architecture, having less parameters than UNET, can distinguish micro waterbodies accurately with shorter training time. Full article

(This article belongs to the Special Issue I3S 2022 Selected Papers)

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8 pages, 2096 KiB

Open AccessCommunication

Determination of the Strain Influence on the InAs/InAsSb Type-II Superlattice Effective Masses

by Tetiana Manyk, Jarosław Rutkowski, Małgorzata Kopytko and Piotr Martyniuk

Sensors 2022, 22(21), 8243; https://doi.org/10.3390/s22218243 - 27 Oct 2022

Viewed by 1454

Abstract

A³B⁵ materials used for the superlattice (SL) fabrication have properties that enable the design of devices optimized for infrared (IR) detection. These devices are used in the military, industry, medicine and in other areas of science and technology. The paper [...] Read more.

A³B⁵ materials used for the superlattice (SL) fabrication have properties that enable the design of devices optimized for infrared (IR) detection. These devices are used in the military, industry, medicine and in other areas of science and technology. The paper presents the theoretical assessment and analysis of the InAs/InAs_1−xSb_x type-II superlattice (T2SL) (grown on GaSb buffer layer) strain impact on the bandgap energy and on the effective masses of electrons and holes at 150 K. The theoretical research was carried out with the use of the commercial program SimuApsys (Crosslight). The k·p method was adopted in T2SL modeling. Luttinger coefficients (γ₁, γ₂ and γ₃) were assessed assuming the Kane coefficient F = 0. The bandgap energy of ternary materials (InAs_xSb_1−x) was determined assuming that the bowing parameter (b_g) for the above-mentioned temperature is b_g = 750 meV. The cutoff wavelength values were estimated based on the theoretically determined absorption coefficients (from approximation the quadratic absorption coefficient). The bandgap energy was calculated according to the following formula: E_g = 1.24/λ_cutoff. The theoretical simulations allowed us to conclude that the strain in T2SL causes the E_g shift, which also has an impact on the effective masses m_e and m_h, playing an important role for the device’s optical and electrical performance. The T2SLs-simulated results at 150 K are comparable to those measured experimentally. Full article

(This article belongs to the Special Issue I3S 2022 Selected Papers)

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11 pages, 5889 KiB

Open AccessArticle

Influence of the Size of Damage to the Steel Wire Rope on the Magnetic Signature

by Paweł Mazurek, Maciej Roskosz and Jerzy Kwaśniewski

Sensors 2022, 22(21), 8162; https://doi.org/10.3390/s22218162 - 25 Oct 2022

Cited by 7 | Viewed by 1525

Abstract

This article presents diagnostic tests of wire ropes using passive magnetic methods. The study used two types of wire ropes with different constructions and diameters. Defects of various depths were modeled in the ropes, which reflected the degree of loss of metallic cross-section. [...] Read more.

This article presents diagnostic tests of wire ropes using passive magnetic methods. The study used two types of wire ropes with different constructions and diameters. Defects of various depths were modeled in the ropes, which reflected the degree of loss of metallic cross-section. After a series of measurements, a correlation was observed between the amplitude of the module signal and the degree of damage to the rope. The signals were recorded with the advantage of the SpinMeter-3D magnetometer. The obtained results were subjected to the extraction of features, the analysis of which allowed the damage to be identified. Full article

(This article belongs to the Special Issue I3S 2022 Selected Papers)

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16 pages, 8425 KiB

Open AccessArticle

Optical Properties of a Tapered Optical Fiber Coated with Alkanes Doped with Fe₃O₄ Nanoparticles

by Karol A. Stasiewicz, Iwona Jakubowska, Joanna E. Moś, Paweł Marć, Jan Paczesny, Rafał Zbonikowski and Leszek R. Jaroszewicz

Sensors 2022, 22(20), 7801; https://doi.org/10.3390/s22207801 - 14 Oct 2022

Cited by 2 | Viewed by 2738

Abstract

The presented research shows the possibilities of creating in-line magnetic sensors based on the detection of changes of light propagation parameters, especially polarization, obtained by mixing Fe₃O₄ nanoparticles with hexadecane (higher alkane) surrounding a biconical optical fiber taper. The fiber [...] Read more.

The presented research shows the possibilities of creating in-line magnetic sensors based on the detection of changes of light propagation parameters, especially polarization, obtained by mixing Fe₃O₄ nanoparticles with hexadecane (higher alkane) surrounding a biconical optical fiber taper. The fiber optic taper allows to directly influence light parameters inside the taper without the necessity to lead the beam out of the structure. The mixture of hexadecane and Fe₃O₄ nanoparticles forms a special cladding surrounding a fiber taper which can be controlled by external factors such as the magnetic field. Described studies show changes of transmission (power, loss) and polarization properties like azimuth, and ellipticity, depending on the location of the mixture on sections of tapered optical fiber. The taper was made of a standard single-mode telecommunication fiber, stretched out to a length of 20.0 ± 0.5 mm and the diameter of the tapers is around 15.0 ± 0.3 μm, with the loss lower than 0.5 dB @ 1550 nm. Such a taper causes the beam to leak out of the waist structure and allows the addition of the external beam-controlling cladding material. The presented research can be used to build polarization switches or optical sensor. The results show that it can be a new way to control the propagation parameters of a light beam using tapered optical fiber and magnetic mixture. Full article

(This article belongs to the Special Issue I3S 2022 Selected Papers)

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14 pages, 7810 KiB

Open AccessArticle

SPR Sensor Based on a Tapered Optical Fiber with a Low Refractive Index Liquid Crystal Cladding and Bimetallic Ag–Au Layers

by Joanna Korec, Karol A. Stasiewicz and Leszek R. Jaroszewicz

Sensors 2022, 22(19), 7192; https://doi.org/10.3390/s22197192 - 22 Sep 2022

Cited by 5 | Viewed by 2380

Abstract

This paper presents a study of the influence of bimetallic layer covers of a tapered optical fiber surrounded by a low refractive index liquid crystal on the properties of light propagation in the taper structure. This research follows previous works on the effect [...] Read more.

This paper presents a study of the influence of bimetallic layer covers of a tapered optical fiber surrounded by a low refractive index liquid crystal on the properties of light propagation in the taper structure. This research follows previous works on the effect of monometallic thin films (Au and Ag). In this case, the total thicknesses of the bimetallic layers were h = 10 nm, and the participation of gold and silver was equal. The films were deposited on one side of the tapered waist area. The liquid crystal cells were controlled with a voltage U from 0 to 200 V, with and without amplitude modulation at a frequency of f_mod = 5 Hz. For the purposes of this research, spectral characteristics were obtained for a wavelength λ ranging from 550 to 1200 nm. Measurements were carried out at room temperature for three types of rubbed layers orientation—orthogonal, parallel, and twist in relation to the fiber axis. Obtained resonant peaks were compared with the previous results regarding the resonant wavelength, peak width, SNR, and maximum absorption. In the presented paper, the novelty is mainly focused on the materials used and their time stability, as well as corresponding changes in the technological parameters used. Full article

(This article belongs to the Special Issue I3S 2022 Selected Papers)

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16 pages, 2619 KiB

Open AccessArticle

Anisotropy of the ΔE Effect in Ni-Based Magnetoelectric Cantilevers: A Finite Element Method Analysis

by Bernd Hähnlein, Neha Sagar, Hauke Honig, Stefan Krischok and Katja Tonisch

Sensors 2022, 22(13), 4958; https://doi.org/10.3390/s22134958 - 30 Jun 2022

Cited by 2 | Viewed by 1743

Abstract

In recent investigations of magnetoelectric sensors based on microelectromechanical cantilevers made of TiN/AlN/Ni, a complex eigenfrequency behavior arising from the anisotropic ΔE effect was demonstrated. Within this work, a FEM simulation model based on this material system is presented to allow an investigation [...] Read more.

In recent investigations of magnetoelectric sensors based on microelectromechanical cantilevers made of TiN/AlN/Ni, a complex eigenfrequency behavior arising from the anisotropic ΔE effect was demonstrated. Within this work, a FEM simulation model based on this material system is presented to allow an investigation of the vibrational properties of cantilever-based sensors derived from magnetocrystalline anisotropy while avoiding other anisotropic contributions. Using the magnetocrystalline ΔE effect, a magnetic hardening of Nickel is demonstrated for the (110) as well as the (111) orientation. The sensitivity is extracted from the field-dependent eigenfrequency curves. It is found, that the transitions of the individual magnetic domain states in the magnetization process are the dominant influencing factor on the sensitivity for all crystal orientations. It is shown, that Nickel layers in the sensor aligned along the medium or hard axis yield a higher sensitivity than layers along the easy axis. The peak sensitivity was determined to 41.3 T⁻¹ for (110) in-plane-oriented Nickel at a magnetic bias flux of 1.78 mT. The results achieved by FEM simulations are compared to the results calculated by the Euler–Bernoulli theory. Full article

(This article belongs to the Special Issue I3S 2022 Selected Papers)

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