Spectrum Of Electromagnetic Waves Research Articles

EVALUAREA COMPORTARII TERMICE A PLANTELOR IN MICROSERA CU SENZORI DE IMAGINE MICROBOLOMETRICI

In this research, the data from temperature measurements obtained with the InfiRay T2S+ device, an infrared thermal imaging camera have been checked to monitor plant thermal behaviour. Plant leaf temperature is a parameter frequently used as representative for stomatal conductance, as stomatal confinement results in attenuated transpiration, and consequently leads to increased plant temperature. Also, to identify the stress of the plant, indices of thermal and modified stress have been calculated. The results obtained show that the Kalanchoe blossfeldiana species chosen for this study, when exposed to extreme values of temperature or water requirements, presented significant changes in the infrared electromagnetic wave spectra.

A STUDY OF THE MATURITY PROCESS OF RED GUTTY KETAN FOOD INGREDIENTS IN TERMS OF THE TASTE: EXTREMELY LOW FREQUENCY MAGNETIC FIELD RADIATION

This study explores the novel effect of an Extremely Low Frequency (ELF) magnetic field on the durability of glutinous tape food, a traditional Indonesian food made from fermented glutinous rice. ELF magnetic field is a spectrum of electromagnetic waves with frequencies less than 300 Hz that can influence microbial activity and the chemical changes in food. The study uses a unique experimental method that exposes 20 glutinous tape samples, divided into a control group and an experimental group, each with 10 samples, to an ELF magnetic field of 1,000μT intensity for 45 minutes. The study uses a Complete Randomized Design (RAL) and analyzes the data using the One Way Anova test with LSD and Kruskal-Wallis tests using IBM SPSS Statistics 23. The results show that the experimental group’s glutinous tape samples did not experience spoilage compared to the control group’s. The study proves the ELF magnetic field's effect on the durability of glutinous tape food and provides insights for developing new food preservation techniques. The study demonstrates the innovation and applicability of using the ELF magnetic field for food durability.

Principle and applications of near‐infrared imaging for fruit quality assessment—An overview

SummaryThe quality (i.e. the degree of excellence and acceptance to the consumer) evaluation and safety of fruit and other agricultural products is by far the main challenging task in the food industries. Hence, the development of efficient non‐invasive, real‐time and rapid‐quality assessment tools and techniques is the need of the hour. This review paper aims to provide the basic or fundamental knowledge regarding the principle, potential and application of near‐infrared imaging‐based computer vision systems. Non‐invasive technologies, based on optical properties, are the most applicable and important for real‐time quality assessment. Absorption, reflection and scattering before the transmission of incident light are phenomenon properties of biological materials. The principle and application of NIR imaging (i.e. medical imaging) in agriculture for quality detection were studied from various published research papers. Thus, collected pieces of information are summarised, concluded and discussed in a unique way in this report. The NIR spectrum of electromagnetic waves has some basic benefits of light penetration into the upper layer and makes visualisation of the targeted area of objects. Several studies have proved that the non‐destructive system based on visible and non‐visible imaging in combination has a significant role in quality defect detection in fruits. In NIR imaging, the artefacts caused by light illumination can be reduced and it will help in the visualisation of biological tissues and hidden defects just below the peel.

Numerical Study of the Spectrum of TE-Polarized Electromagnetic Waves of a Goubau Line Coated with Graphene

Numerical Study of the Spectrum of TE-Polarized Electromagnetic Waves of a Goubau Line Coated with Graphene

Maximizing solar energy production in ASEAN region: Opportunity and challenges

The Southeast Asian (SEA) region has witnessed a relentless surge in energy demand, driven by rapid urbanization, industrialization, and economic growth. In response, the exploration and development of renewable energy sources have gained significant attention. Among these sources, solar energy has emerged as a highly promising candidate due to its remarkable growth rate. This comprehensive review article aims to analyze the challenges and opportunities involved in maximizing solar energy production in the SEA region. The article commences with a succinct introduction to electromagnetic wave spectra and emphasizes the significance of visible spectra. It then provides a comprehensive examination of gross horizontal irradiance (GHI) patterns across the SEA region. A systematic tabulation is presented, organizing the current and potential solar energy installations and outputs of ASEAN countries. The article explores the deployment of hybrid photovoltaic (PV) systems, particularly floating PV installations, as an effective strategy to reduce dependence on fossil fuels. Moreover, the utilization of Supervisory Control and Data Acquisition (SCADA) systems for optimizing solar PV output is investigated. The article further delves into critical maintenance protocols, encompassing corrective, emergency, preventive, and predictive measures, and explores the levelized cost of electricity (LCOE) to assess the profitability of solar PV installations. Lastly, the leadership of Malaysia, Indonesia, and Singapore in solar PV research is highlighted, with a specific focus on building integrated PV and floating PV research. By addressing these, this review article offers valuable insights into the challenges and opportunities for advancing solar energy production in the SEA region.

Special Issue on the Progress and Application of Electromagnetic Materials

Electromagnetic materials refer to materials that can manipulate electromagnetic waves, which can control the amplitude, phase, polarization, spectrum, and other characteristics of electromagnetic waves [...]

Mixed Pixel Classification on Hyperspectral Image Using Imbalanced Learning and Hyperparameter Tuning Methods

Hyperspectral image technology in land classification is a distinct advantage compared to ordinary RGB and multispectral images. This technology has a wide spectrum of electromagnetic waves, which can be more detailed than other types of imagery. Therefore, with its hyperspectral advantages, the characteristics of an object should have a high probability of being recognized and distinguished. However, because of the large data, it becomes a challenge to lighten the computational burden. Hyperspectral has a huge phenomenon that makes computations heavy compared to other types of images because this image is 3D. The problem faced in hyperspectral image classification is the high computational load, especially if the spatial resolution of the image also has mixed pixel problems. This research uses EO-1 satellite imagery with a spatial resolution of 30 meters and a mixed pixel problem. This study uses a classification method to lighten the computational burden and simultaneously increase the value of classification accuracy. The method used is satellite image pre-processing, including geometric correction and image enhancement using FLAASH while the corrections are geometric correction and atmospheric correction. Then to lighten the computational burden, the steps carried out are using the Slab and PCA method. After obtaining the characteristics, they are entered into a guided learning model using a support vector machine (SVM) for the five-class or multiclass classification. Moreover, the imbalance learning method is proven to produce increased accuracy. The best results were achieved by the ADASYN method with an accuracy of 96.58%, while the computational time became faster with the feature extraction method.

Study of Driving Force and Surface Current Patterns in Labuan Bajo from High Frequency Radar data from October to December 2018

Surface ocean current data in Labuan Bajo from October to December 2018 for determine the characteristics of the surface current and identify the influence of wind and tides in generating surface current. The current data set is derived from measurements of high frequency (HF) radar, which operates on the electromagnetic wave spectrum at high frequency or short wave. Method of data analysis by processing surface current velocity and direction of the zonal and meridional into spatial and temporal graphs. The result showed the average current speed in October was 0.13 m/s, the average current speed in November was 0.12 m/s, and the average current speed in December was 0.09 m/s. The empirical orthogonal function (EOF) Mode 1 has a variance of 56.2% because of the tides, Mode 2 has a variance of 26.6% because of bi-weekly variability, and Mode 3 has a variance of 17.2% because of the intra-seasonal period. This shows that tides have a greater influence on the study region than any other driving force. These results are intended to be useful to the public, particularly in terms of sustainable coastal marine management in Labuan Bajo. Especially in terms of preventing boat accidents caused by ocean currents.

Composite Insulator Defect Identification Method Based on Acoustic–Electric Feature Fusion and MMSAE Network

Aiming to solve the partial discharge problem caused by defects in composite insulators, most existing live detection methods are limited by the subjectivity of human judgment, the difficulty of effective quantification, and the use of a single detection method. Therefore, a composite insulator defect diagnosis model based on acoustic–electric feature fusion and a multi-scale perception multi-input of stacked auto-encoder (MMSAE) network is proposed in this paper. Initially, during the withstanding voltage experiment, the electromagnetic wave spectrometer and ultrasonic detector were used to collect and process the data of six types of composite insulator samples with artificial defects. The electromagnetic wave spectrum, ultrasonic power spectral density, and n-S map were then obtained. Then, the network architecture of MMSAE was built by integrating a stacked auto-encoder and multi-scale perception module; the feature extraction and fusion methods of the electromagnetic wave spectrum and ultrasonic signal were investigated. The proposed method was used to diagnose test samples, and the diagnostic results were compared to those obtained using a single input source and the artificial neural network (ANN) method. The results demonstrate that the detection accuracy of acoustic–electric feature fusion is greater than that of a single feature; the accuracy of the proposed method is 99.17%, which is significantly higher than the accuracy of the conventional ANN method. Finally, composite insulator defect diagnosis software based on PYQT5 and Keras was developed. Ten 500 kV aging composite insulators were used to validate the effectiveness of the proposed method and design software.

General equation of the achromatic stigmatic singlet.

The merge of two models is presented: the achromatic principle and the general equation of the stigmatic lens [J. Opt. Soc. Am. A39, 1524 (2022)JOAOD60740-323210.1364/JOSAA.460993; Appl. Opt.57, 9341 (2018)APOPAI0003-693510.1364/AO.57.009341]. The achromatic principle expresses the bases to design an optical imaging system rigorously free of chromatic aberrations for a given spectrum of electromagnetic waves. It has been applied only to Cartesian ovals. On the other hand, the equation of the stigmatic lens gives a perfect point image for a single wavelength. The merge consists of generalizing the equation of the stigmatic lens to be stigmatic for a given spectrum of electromagnetic waves based on the achromatic principle. The constraints to rigorously achieve the achromatic stigmatic singlet are studied in detail. No paraxial concepts are used, and no iteration process is required. An example of an achromatic stigmatic singlet is presented, and the results are as expected by theory.

A Deep Learning Approach to Extracting Nuclear Matter Properties from Neutron Star Observations

Understanding the equation of state of dense neutron-rich matter remains a major challenge in modern physics and astrophysics. Neutron star observations from electromagnetic and gravitational wave spectra provide critical insights into the behavior of dense neutron-rich matter. The next generation of telescopes and gravitational wave detectors will offer even more detailed neutron-star observations. Employing deep learning techniques to map neutron star mass and radius observations to the equation of state allows for its accurate and reliable determination. This work demonstrates the feasibility of using deep learning to extract the equation of state directly from observations of neutron stars, and to also obtain related nuclear matter properties such as the slope, curvature, and skewness of nuclear symmetry energy at saturation density. Most importantly, it shows that this deep learning approach is able to reconstruct realistic equations of state and deduce realistic nuclear matter properties. This highlights the potential of artificial neural networks in providing a reliable and efficient means to extract crucial information about the equation of state and related properties of dense neutron-rich matter in the era of multi-messenger astrophysics.

Tailoring Group Delay Dispersion of Spatial Phaser using Anisotropic Metasurface and Polarized Incident Waves

AbstractMetasurface‐based spatial phaser, exhibiting dispersive group delay responses, is able to perform real‐time analogue signal processing on the temporal spectrum of spatial electromagnetic waves, e.g., Fourier transformation, pulse chirping, pulse spread, and compression. The functionality of a spatial phaser is closely related to its group delay dispersion slope. For instance, for an up‐chirped incident pulse, the positive‐slope‐dispersion phaser spreads the pulse whereas the negative‐slope‐dispersion one compresses the pulse. Most reported spatial phasers exhibit fixed dispersion slopes and hence perform single functionality only, which cannot meet the demand of multifunctional systems in communication and sensing applications. In this paper, a new way is proposed to control and tune the dispersion slope of spatial phasers using polarization of incident waves, which is simpler and more efficient than conventional approaches based on tunable circuits. To verify the proposed method, a first‐order spatial phaser is designed and experimentally demonstrated within 9.4–10.6 GHz. It is able to generate negative‐slope, positive‐slope, and zero‐slope group delay dispersions, in case of x‐, y‐, and ±45°‐polarized waves. Such a reconfigurable phaser may find wide applications in integrated communication and sensing.

Laboratory implementation of Fourier transform infrared (FTIR) spectrograph using a super-continuum laser

Fourier Transform infrared (FTIR) spectroscopy is a technique to indirectly measure the spectrum of electromagnetic wave over a broad range. The vibrational response signature will be revealed through the absorption spectrum. The super-continuum laser is the appropriate option for using as a light source of FTIR because of its broad spectral bandwidth and high spatial coherence, which could expand the observable region. In this work, a custom design of laboratory prototype of FTIR system using a super-continuum laser with a wavelength in the range of 1500 – 2 400 nm (6667 – 4167 cm−1) is presented. The system was designed to have a combination of monochromatic and broadband interferometers in a free space Michelson interferometer configuration. An interferogram of a monochromatic laser at 532 nm (18 797 cm−1) was used to correct the phase distortion in the interferogram of the broadband light source. The location of peaks and valleys of the monochromatic interferogram were used to resample the broadband interference signal. The resulting spectrum was analyzed and then compared to the theoretical spectrum for further performance improvements.

Analysis of pH Changes in Cassava Fermentation Process Exposed to ELF Magnetic Fields Intensity 100𝜇T, 200𝜇T and 300𝜇T

ELF (Exemelly Low Frequency) is a spectrum of electromagnetic waves with a frequency of less than 300 Hz. This study aims to determine the effect of exposure to the ELF magnetic field on the degree of acidity (pH) in the maturation process of cassava tape. The research method used is a true experiment, namely by giving exposure to the ELF magnetic field in the experimental group and not giving exposure to the ELF magnetic field in the control group. Exposure to the ELF (Extremely Low Frequency) magnetic field on cassava tape used intensities of 100𝜇T, 200𝜇T, and 300𝜇T with various exposure times, namely 30 minutes, 60 minutes, and 90 minutes. The type of research used is experimental research with a completely randomizedidesign (CRD) which aims to examine the effect of treatment by repeating the experiment. Data collection was carried out after the 1st day to the 4th day. The results showed that exposure to ExtremelyiLowiFrequencyi(ELF) magnetic fields can affect the average pH value in the cassava tape fermentation process which is shown through variations in the bar chart. The experimental group samples (E100𝜇T 60') and (E300𝜇T 30') on day 1 to day 4 there was a significant change in pH value.

New Approach to Cross-Correlation Reflectometry Diagnostics of Nonlocality of Plasma Turbulence

One of the most important properties of stochastic nonlinear processes, including the turbulence of the hydrodynamic motion of continuous media, is distant spatial correlations. To describe them, an approach was proposed by Shlesinger and colleagues based on a linear integro-differential equation with a slowly decaying kernel, which corresponds to superdiffusion (nonlocal) transfer in the regime of Lévy walks (Lévy flights when the finite velocity of the carriers is taken into account). In this paper, we formulate a similar approach that makes it possible to formulate the problem of determining these properties from the scattering spectra of electromagnetic (EM) waves and cross-correlation reflectometry. A universal description of the relationship between the observed symmetric quasi-coherent component in the spectrum of scattered EM waves in plasmas and a process of the Mandelstam–Brillouin scattering type is obtained. It is shown that the nonlocality of spatial correlations of density fluctuations in a turbulent medium is due to long-free-path carriers of the medium’s perturbations, for which the free path distribution function is described by the Lévy distribution. The effectiveness of the proposed method is shown by the example of the interpretation of the data of cross-correlation reflectometry of EM waves in the radio-frequency range for the diagnosis of turbulent plasma in magnetic confinement devices for axisymmetric toroidal thermonuclear plasma.

Theoretical Studies of One Dimensional DNA Templated Silica/Metal Oxides, Graphite Oxide Photonic Crystals

We have designed one dimensional photonic crystals of Silica /Metal oxides (Alumina and ZnO), Silica/Graphite oxide on DNA template and investigated their optical responses in the 200 -2000 nm region of electromagnetic wave spectra theoretically using transfer matrix method (TMM). It is observed that in the presence of DNA template, the number, width and position of the photonic band gap are changed significantly. These results point that DNA templated proposed photonic crystals can be used for tuning the bandgap for desired spectra. This feature of DNA templated photonic crystals can be used for enhancing the transmission properties of photonic crystals. By tuning the bandgap effect for the desired frequency, the DNA templated photonic crystals can be applied for sensing the biomarkers. The theoretical results show that the DNA templated Silica based photonic crystals will be a promise for cost effective and fast responding label free biosensing applications.

Evaluation of the effect of inactivation by microwave and autoclave in homeopathic medicines

Background: The Brazilian Pharmacopoeia defines the sterilization process as a "method" intended to remove or destroy all forms of life, animal or plant, macroscopic or microscopic, saprophytic or not, present in the product concerned, without ensuring the complete inactivation of toxins or cellular enzymes. Microwaves are electromagnetic waves with frequencies ranging between 300MHz (300x106 Hz) and 300 GHz (300x109 Hz) and wavelengths from 1 m to 1 mm[1]. They are waves that lie within the region between TV waves and the infrared region within the spectrum of electromagnetic waves. According to the Technical Standards Textbook for Homeopathic Pharmacy, glass tubes may be reused after washed with running and purified water and inactivated by autoclaving at 120oC for 30 minutes or by a dry air buffer at 180oC for 30 minutes or at 140oC for 1 hour [2].
 
 Aims: Current experiment evaluates the influence of ultra-diluted Sulphur with and without inactivation by autoclaving and microwaving for certain variables in the germination and growth of sorghum (Sorghum bicolor L. Moench - cv TX623B).
 
 Methodology: Ten milliliters of Sulphur in homeopathic dinamizations (proposed by Hering - DH) 9DH, 18DH and 30DH inactivated by microwave and by autoclave heat, and control with water, were added to petri dishes in which 20 sorghum seeds were distributed. The experiment was conducted in a growth chamber (BOD) at 25oC and during a 16-h photoperiod. Double-blind methodology to avoid researcher’s possible interferences or trends, coupled to statistic treatment at the end of the experiment, was employed. Data underwent variance analysis and means were compared by Scott-Knott’s test at 5% probability.
 
 Results: Homeopathy Sulphur changed the evaluated parameters of 9DH, 18 DH and 30 DH dinamizations when compared to control (water). Differences existed with regard to effects of the different microwave-treated (M9DH, M18DH, M30DH) and autoclaving-treated (A9DH, A18DH, A30DH) dinamizations. Sulphur had no significant difference in the aerial length (CPA) when compared with that of control. In the case of the same homeopathic treatments previously undergoing autoclaving, the three dinamizations had a similar response to CPA. The same occurred with drugs submitted to microwaves. With regard to root’s growth (CSR), treatment with Sulphur inhibited growth in the dinamizations 18 DH and 30 DH when compared to control. This did not occur with 9 DH which had the same effect as that of water. In the case of groups treated with medicines 30 DH and 9DH undergoing microwaves, the same effect of water was reported. Consequently, microwaves inactivated the effect of homeopathic medicine. However, in 18DH under the effect of microwaves, the effect of drug 18DH was reported. Consequently, there was growth inhibition but no inactivation by microwaves. In the case of groups treated with autoclaved medicine, a greater root growth was reported. This fact shows that autoclaving altered the homeopathic medicine. In fact, it had an opposite effect when compared to control. On the other hand, when Fresh Root Weight was evaluated, differences in control were reported only for groups treated with autoclaved medicines. These results were similar to those of the group treated with medicine 18DH. An increase in the fresh root weight was reported agreeing with a greater root growth. Results related to the aerial part and to the root of the dry mass failed to show any significant difference among the groups.
 
 Conclusions: Results show that different physiological responses are produced posterior to the employment of homeopathic medicine, sometimes stimulating, sometimes inhibiting root growth . The aerial part was not influenced by any treatment. On the other hand, autoclaved medicines stimulated root growth[3] [4]. This fact shows changes in the homeopathic medicine under humid heat. Microwave treatments showed an inactivation for 9DH and 30DH, but not for 18DH. The latter had the same results as those treated with Sulphur 18DH. The above results suggest that microwaves may inactivate homeopathic medicines, albeit not entirely. Therefore, it may not be a reliable inactivation methodology.

Research On Radial Electromagnetic Force and Vibration Response Characteristics of Squirrel-Cage Induction Motor Fed By PWM Inverter

In order to study the influence of current harmonics generated by PWM inverter on radial electromagnetic force and vibration response of squirrel-cage induction motor, an analysis method is introduced in this paper. Firstly, the relationship among the order and frequency of electromagnetic force wave of the motor under the action of harmonic current is analyzed theoretically. Secondly, a squirrel-cage induction motor is used to build a vibration response analysis model with multiple physical field coupling. The electromagnetic force wave and vibration response spectrum of the motor under sinusoidal power supply and PWM harmonic power supply are obtained. The results show that: for the prototype, the frequency components of 0-order, 2 (2p) order electromagnetic force wave will be introduced when the harmonic current of the inverter is supplied. Finally, the correctness of the analysis method is verified by the vibration experiment of the prototype.

A study of transmission on cylindrical photonic quasicrystals

We study the transmittance spectra of light waves propagating on binary quasiperiodic cylindrical stackings. Such structures are called Cylindrical Photonic Quasicrystals (CPQs). In our model, Maxwell's equations are solved, and amplitudes of fields on distinct layers, for each generation of the cylindrical stackings, are linked through appropriate boundary conditions. Then, a transfer-matrix formalism is used to obtain the allowed and forbidden modes. We use both SiO 2 and TiO 2 as the binary components of the CPQs, and consider four distinct aperiodic stackings: Thue–Morse, Fibonacci, Octonacci, and Double–Period. Our results show that the transmission spectra for TE and TM waves, in all generations of the four sequences, did not present a perfect specular symmetry for both SiO 2 and TiO 2 . Also, we found that the transmission rates of the TE waves are higher than the ones of the TM waves. We also observed for Fibonacci and Octonacci CPQs that, for TM modes only, there exist refraction-index-independent bandgaps. • We analyze the reflection, transmission, and absorption spectra of electromagnetic waves. • The waves propagate in Cylindrical Photonic Quasicrystals (CPQs). • We consider four distinct CPQs: Fibonacci, Octonacci, Thue--Morse and Double-Period. • Our results show that the transmission spectra for TE and TM waves did not present a perfect specular symmetry. • We also observed for Fibonacci and Octonacci CPQs that two refraction-index-independent bandgaps exist for TM modes only.

(Invited) Optoelectronic Application of Colloidal Quatum Dots in Infrared Beyond Si

Among electromagnetic wave spectrum, infrared region has many attractive applications such as a LiDAR, optical communication, telecommunications, thermography, bioimaging, photovoltaics, and night visions. However, the expensive cost of epitaxial III-V semiconductors and the fabrication process hinders the widespread of the infrared technology beyond the silicon absorption range. Colloidal quantum dots have a great potential as an alternative materials for infrared detection. Lead chalcogenide QDs not only have tunable bandgap in infrared region but also have process compatibility with conventional Si ROIC in the device fabrication process, which remarkably reduces fabrication costs. The performance of photodetectors incorporating the lead chalcogenide QDs, however, is suboptimal and needs further improvement. One of the main factors limiting the performance of QD-based photodetectors is a high density of surface defects. QDs inherently have large surface-to-volume ratios and dangling bonds on the surface acted as trap sites. Various methods to reduce surface defects, such as thermal and ligand treatment, have been introduced; however, even after these treatments, QD-based photodetectors still show the relatively low detectivity (D*). In this work, we demonstrate the various approaches to improve the performance of infrared photodetectors and their results. We focused on the reducing the trap density by the surface treatment of QDs using thermal annealing and chemical treatment in order to improve the device performance. We developed the chemical treatment method for reducing trap states with maintaining the existing ligands. Thermal annealing also can reduce the trap density; however, it sintered QDs by atomic diffusion. We found optimal condition for reducing the surface traps with suppressing sintering. The effects of these treatments were evaluated by the device performance and trap characterization. These approaches improve the bandwidth and the responsivity compared to reference devices. Moreover, we treated the surface of QD layers to show the interfacial effect on the QD devices.