Realization Of Filters Research Articles

Selective and highly sensitive measurement of H2O2 and organic hydroperoxides with PtNP/Poly(Brilliant Green)/SPCE

This research presents a novel electrochemical approach for the selective measurement of hydrogen peroxide and organic hydroperoxides, which is pivotal in many fields. The study details the development of an advanced sensor using a one-pot, one-step synthesis to embed platinum nanoparticles within a 3D-polymeric matrix of poly (brilliant green) on screen-printed carbon electrodes. The modified surfaces were characterized using scanning and transmission electron microscopy, Raman spectroscopy, cyclic voltammetry and electrochemical impedance spectroscopy. The results obtained by amperometry showed that, at 0.1 V, only H2O2 produced an electrochemical signal, while, at higher potential (0.5 V), all the hydroperoxides tested exhibited an electrochemical signal. Sensitivities obtained for H2O2 by flow injection analysis were 431 ± 3 and 465 ± 4 μC mM−1 at 0.1 and 0.5 V, respectively, with detection limits (S/N = 3) 116 and 30 nM, respectively. For organic hydroperoxides, sensitivities ranged from 22.3 to 32.6 μC mM−1 at 0.5 V, and limits of detection from 1.15 to 5.95 μM. Chemometric analysis indicated the sensor can satisfactorily measure H2O2 in the presence of the organic hydroperoxides herein analysed. The proposed sensor showed excellent properties in terms of repeatability, reproducibility and stability, with minimal interference. The reliability of the sensor was verified by measuring hydroperoxides spiked in aqueous extracts from real air quality monitoring filters. These features highlight the suitability of the sensor for hydroperoxide measurement and underscore its reliability as a practical tool for real-world applications.

High Q factor of photonic cavity with SU-8 photoresist micro-disk for electromagnetic wave control

How to control electromagnetic wave effectively is the key to the realization of applicable filters in many optics technologies. In our work, a SU-8 photoresist micro-disk is written onto a photonic crystal waveguide to control electromagnetic wave. Corresponding simulation and experiment shows that, the quality Q increases as the thickness of SU-8 smaller. When the thickness exceeds 400 nm, the change of thickness has little influence on electromagnetic waves. Besides, the increase of the radius of disc-shaped SU-8 can also increase the Q value. By optimizing the simulation and experimental data, we can successfully create a SU-8 photoresist micro-disk cavity with the thickness of 5 µm and height of 20 nm, the quality factor of Q can reach 8200. However, longer exposure time and more stable experimental equipment is needed if we want to get a larger radius. The method in our work by using SU-8 photoresist micro-disk on photonic crystals to control electromagnetic wave is more practical and flexible, which can provide new significance for research into optical filter.

Developing augmented reality filters to display visual cues on diverse skin tones

Introduction: Variations in skin tone can significantly alter the appearance of symptoms such as rashes or bruises. Unfortunately, previous works utilizing Augmented Reality (AR) in simulating visual symptoms have often failed to consider this critical aspect, potentially leading to inadequate training and education. This study seeks to address this gap by integrating generative artificial intelligence (AI) into the AR filter design process.Methods: We conducted a 2 × 5 within-subjects study with second-year nursing students (N = 117) from the University of Florida. The study manipulated two factors: symptom generation style and skin tone. Symptom generation style was manipulated using a filter based on a real symptom image or a filter based on a computer-generated symptom image. Skin tone variations were created by applying AR filters to computer-generated images of faces with five skin tones ranging from light to dark. To control for factors like lighting or 3D tracking, 101 pre-generated images were created for each condition, representing a range of filter transparency levels (0–100). Participants used visual analog scales on a computer screen to adjust the symptom transparency in the images until they observed image changes and distinct symptom patterns. Participants also rated the realism of each condition and provided feedback on how the symptom style and skin tone impacted their perceptions.Results: Students rated the symptoms displayed by the computer-generated AR filters as marginally more realistic than those displayed by the real image AR filters. However, students identified symptoms earlier with the real-image filters. Additionally, SET-M and Theory of Planned Behavior questions indicate that the activity increased students’ feelings of confidence and self-efficacy. Finally, we found that similar to the real world, where symptoms on dark skin tones are identified at later stages of development, students identified symptoms at later stages as skin tone darkened regardless of cue type.Conclusion: This work implemented a novel approach to develop AR filters that display time-based visual cues on diverse skin tones. Additionally, this work provides evidence-based recommendations on how and when generative AI-based AR filters can be effectively used in healthcare education.

RCVM‐ASS‐CICSKA‐PAPT‐VDF: VLSI design of high‐speed reconfigurable compressed Vedic PAPT‐VDF filter for ECG medical application

AbstractDuring signal acquisition, the signals are impacted by multiple noise sources that must be filtered before any analysis. However, many different filter implementations in VLSI are dispersed among many studies. This study aims to give readers a systematic approach to designing a Pipelined All‐Pass Transformation based Variable digital filter (PAPT‐VDF) to eliminate the high‐frequency noise from ECG data. The modified design emphasizes first‐ and second‐order responses to obtain high‐speed filter realization with high operating frequencies. The addition of adder and multiplier designs to the hardware architecture of a filter design improves performance. The fundamental blocks of the filter design are the adder and multiplier. The adder and multiplier are employed with an Adaptable stage size‐based concatenation, incremented carry‐skip adder (ASS‐CICSKA), and Improved reconfigurable compressed Vedic multiplier (IRCVM). Utilizing the adder design diminishes the delay with enhanced performance because receiving the carry from an incrementation block is not mandatory. In the multiplier design, the compressor and the reconfigurable approach are adapted with a data detector block to detect the redundant input and lower the logic gates' switching activity with less area overhead. The proposed filter design is implemented in vertex 7 FPGA family device, and the performance measures are analyzed regarding area utilization, delay, power, and frequency. Also, by using the denoised signal, the mean square error (MSE), and signal‐to‐noise ratio (SNR) are evaluated in the MATLAB platform.

Quasi-bound states in the continuum empowering a transmissive terahertz narrowband filter with high Q and a broad sideband free of interferential distortion.

Most currently available terahertz (THz) narrowband filters contain a metal and a substrate, which introduce absorption loss and spectral fluctuations caused by a Fabry-Perot interference in substrates. To address these issues, we employ quasi-bound states in the continuum (BICs) for the design and realization of a substrate-free all-dielectric THz transmissive narrowband filter. Under oblique incidence, the symmetry-protected BICs break and collapse into high-Q transmissive quasi-BIC modes, thereby achieving narrowband filtering. The filter not only minimizes energy loss but also demonstrates a smooth filtering response without an interferential spectral fluctuation associated with the substrate. An experimental high Q value of ∼127 at 4.1 THz with a broad sideband of ∼1.5 THz with transmittance below 10% is achieved.

Analysis of the shear stresses in a filling line of parenteral products: The role of sterilizing filters

This study investigates the impact of shear stress on protein-based parenteral drug products, particularly during the filling process, with a focus on the filtration unit. A 3D computational replica of a real sterilizing filter was developed using a stochastic geometry generation methodology, able to replicate realistic values of permeability, porosity, and pore size distribution. Computational Fluid Dynamics simulations were employed to analyze fluid dynamics within the filtration unit. The evolution of shear stress for massless tracers was examined to assess average shear stress in the sterilizing filtration unit. The results provide insights into shear stress dynamics and suggest potential scale-down strategies for industrial applications. The presented analysis is novel compared to most estimations of shear stress in sterilizing filtration units, which generally rely on mathematical calculations.

On the minimization of multiplier-adders for powers-of-two filter using a novel right to left (R2L) algorithm

The field of digital signal processing has been receiving increasing attention over the years because of its widespread applications in various fields of science, engineering and technology. In connection to this, design of finite impulse response (FIR) filter has drawn enough attention of researchers throughout the globe. A number of promising developments has been carried out over the last few decades which emphasize on the design of hardware efficient filter structure. In this work, one novel Right to Left (R2L) algorithm is proposed which can minimize the number of multiplier-adders for the powers-of-two FIR filter. The requirement of such adders essentially depends upon the number of such non-zero entries and the word-length of the input signal. Comparative study has been performed amongst few such hardware efficient realizations of digital filters. Finally, the proposed approach has been implemented using Xilinx Plan Ahead 14.7 so as to have a clear understanding about the requirement of different hardware blocks on a field programmable device.

A Design Method and Application of Meta-Surface-Based Arbitrary Passband Filter for Terahertz Communication.

A meta-surface-based arbitrary bandwidth filter realization method for terahertz (THz) future communications is presented. The approach involves integrating a meta-surface-based bandstop filter into an ultra-wideband (UWB) bandpass filter and adjusting the operating frequency range of the meta-surface bandstop filter to realize the design of arbitrary bandwidth filters. It effectively addresses the complexity of designing traditional arbitrary bandwidth filters and the challenges in achieving impedance matching. To underscore its practicality, the paper employs silicon substrate integrated gap waveguide (SSIGW) and this method to craft a THz filter. To begin, design equations for electromagnetic band gap (EBG) structures were developed in accordance with the requirements of through-silicon via (TSV) and applied to the design of the SSIGW. Subsequently, this article employs equivalent transmission line models and equivalent circuits to conduct theoretical analyses for both the UWB passband and the meta-surface stopband portions. The proposed THz filter boasts a center frequency of 0.151 THz, a relative bandwidth of 6.9%, insertion loss below 0.68 dB, and stopbands exceeding 20 GHz in both upper and lower ranges. The in-band group delay is 0.119 ± 0.048 ns. Compared to reported THz filters, the SSIGW filter boasts advantages such as low loss and minimal delay, making it even more suitable for future wireless communication.

Theoretical analysis of bulk acoustic wave resonators with emerging ε -Ga2O3 piezoelectric film

In this paper, the theoretical analysis of 2.3 GHz bulk acoustic wave (BAW) resonators with emerging ε-Ga2O3 piezoelectric films was investigated. By using the finite element method to calculate the dispersion curve of the BAW resonator based on ε-Ga2O3, we designed and optimized the Bragg reflector structure as well as the metal frame to suppress transverse energy leakage. When the width of the raised metal frame is an odd multiple of the quarter wavelength of the S1 Lamb mode, the vibration displacement at the boundary of the resonators is significantly suppressed, and the acoustic energy is concentrated as much as possible in the effective area of the resonators, resulting in improvement of the Qp and Qmax. Therefore, the ε-Ga2O3 based BAW resonators with Bode Qmax (∼1488), electromechanical coupling coefficient k2eff (∼15%), and the figure of merit (FoM) coefficient (∼223) are simulated and designed. Detailed theoretical analysis provides the key theoretical guidance and design scheme for the realization of ε-Ga2O3 BAW filters. The above-mentioned results imply that the emerging ε-Ga2O3 piezoelectric semiconductors have application prospects in BAW resonators and radio frequency front-end fields.

Logarithmic Learning Differential Convolutional Neural Network

Convolutional Neural Networks (CNNs) have revolutionized image classification through their innovative design and training methodologies in computer vision. Differential convolutional neural network with simultaneous multidimensional filter realization improved the performance of the convolutional neural network with calculation cost drawback. This paper introduces logarithmic learning integration into the differential Convolutional neural network to overcome the drawback by supplying faster error minimization and convergence. This task is done by incorporating LogRelu activation, a Logarithmic Cost Function, and unique logarithmic learning method. The effectiveness of the proposed approaches are evaluated by using various datasets and SGD/Adam optimizers. The first step is the adaptation of LogRelu activation function to convolutional and differential convolutional neural networks. The experiment results show that LogRelu integration to convolutional neural network and differential convolutional neural network yields performance improvements ranging from 1.61% to 5.44%. The same integration on ResNet-18, ResNet-34, and ResNet-50 enhances top-1 accuracy in the range of 3.07% and 9.96%. In addition to LogRelu activation function, a Logarithmic Cost Function with logarithmic learning method is also proposed and adapted to differential convolutional neural network. These improvements lead to a new differential convolutional neural network named as Logarithmic Differential Convolutional Neural Network (LDiffCNN), It consistently outperforms standard CNN by increasing the accuracy up to 3.02%. Notably, Logarithmic Differential Convolutional Neural Network demonstrates reduced training iterations up to 38% with faster convergence. The experimental results proved the efficiency of the proposed approach.

Realization of fractional order lowpass filter using different approximation techniques

Many research groups are starting to pay serious attention to the problem of fractional-order circuits. In this paper, a new approach to designing fractional order low-pass filter (FOLPF) is presented. Finding a rational approximation of the fractional Laplace operator sα is a crucial step in the design of fractional order filters. A comparative study of the most widely used approximation techniques named continued fraction expansion (CFE) method and Biquadratic Approximation (RE) method is performed. Then the transfer function of the proposed FOLPF is calculated. Using operational amplifier, the proposed filter is synthesized. The proposed circuit is simulated using Texas instruments TINA software. The results obtained outperform the existing methods.

Realization of a single-mode plasmonic bandpass filter based on a ring-shaped resonator and silver nanorods

Realization of a single-mode plasmonic bandpass filter based on a ring-shaped resonator and silver nanorods

The Singlet: Direct Synthesis of Pseudo-Elliptic Inline Filters With Frequency Variant Couplings

A general and direct synthesis of <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$N_{p}$</tex-math> </inline-formula> poles pseudo-elliptic inline filters having <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$N_{p}$</tex-math> </inline-formula> purely real and/or imaginary frequency transmission zeros is presented. Using an appropriate model of the resonators (bandpass distributed or lumped element) and shifting the reference planes at the input and output of the filter network, a novel direct synthesis and realization of filters based on frequency variant coupling (inductive or capacitive) in the distributed domain is demonstrated for accurate modeling of narrow and broadband filters. First, a complete general synthesis procedure is described that allows for flexible or mixed topologies realizing transmission zeros anywhere on the frequency plane (including complex and infinite frequencies). Furthermore, by exploiting the power of modular design, a synthesis procedure that enables simultaneous extraction of reflection zero (a pole) and a transmission zero in the form of a symmetrical and physically realizable singlet as an elementary unit is showcased. The physical dimensions of the extracted singlets are independently determined in any chosen technology, and the overall filter is obtained by directly cascading the physical singlets. To validate this novel synthesis technique, three design examples are shown: a narrowband four-pole, four transmission zeros (fully canonical) filter from literature is synthesized and physically dimensioned, a wideband three-pole, three transmission zero (fully canonical) filter, and a broadband three-pole, one transmission zero, filter. In the first two examples, each of the singlet blocks was implemented in an overmoded rectangular waveguide cavity operating at the TE <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$_{201}$</tex-math> </inline-formula> mode coupled at the input and output to the fundamental nonresonating TE <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$_{10}$</tex-math> </inline-formula> mode. The third example was implemented in a re-entrant coaxial resonator operating at the fundamental mode. The simulation of the electromagnetic (EM) high-frequency structure simulator (HFSS) models of the overall example filters was in excellent agreement with the synthesized models, thereby validating the effectiveness of the proposed synthesis technique. Furthermore, the measured results of the fabricated wide bandpass filter showed close agreement with synthesis and EM model.

Parallel-coupled bandpass filters with directly coupled input and output resonators

A novel method for modifying input and output coupling in the parallel-coupled bandpass filters, which allows for direct connection of source and load to the outer resonators, is proposed. In the filter modification a coupled-resonator approach is utilized, which allows one for calculating both the impedance of the introduced new quarter-wave section and the necessary coupling modification of the first and second resonators. The proposed filter modification allows for realization of wider bandwidth filters by removing the necessity of narrow gap realization. Further the following gap in the filter is also enhanced, what helps in wide band filter realization. The presented theoretical approach has been confirmed by theoretically calculated responses of three- and seven-resonator filters. The theoretically investigated filter modification has been confirmed with the experiment in which a seven-resonator modified bandpass filter has been fabricated and measured. The presented measurement results confirm the theoretical predictions and prove the proposed design method.

Active RC Realization of a First-Order All-Pass Filter with a Difference Amplifier

In this tutorial article, we present an active RC realization of a first-order all-pass filter using a difference amplifier. It has the desirable feature of equal resistors, which eases its fabrication, particularly in the IC form. A detailed analysis is followed by design considerations.

Alernative Designs of an Active RC Realization of the Fourth Order Lowpass Butterworth Filter

In this tutorial article, we present two alternative designs of an active RC realization of the fourth-order lowpass Butterworth filter, in order to reduce the element spreads below those of an existing design, which uses a single amplifier of gain 2. The first method is based on simple observation of the design graphs given there, while the second one is a cascade of two second-order realizations, each using a unity gain amplifier. It is shown that retaining the capacitor spread to unity in the first design, a small adjustment of the gain reduces the resistance spread to less than half of the value obtained earlier. It is also shown that in the cascade design, the resistance spread can be made unity, but only at the cost of capacitor spread of 6.834.

Three inputs and one output voltage-mode universal biquadratic filter using one CCII and one CCIII

A voltage-mode universal biquadratic filter using one second-generation current conveyor (CCII), one third-generation current conveyor (CCIII), two capacitors and two resistors is presented. The proposed voltage-mode biquadratic circuit has three input terminals and one output terminal and can realize all the standard filter functions that are highpass, bandpass, lowpass, notch and allpass filters without changing the circuit topology. Both its active and passive sensitivities are small. The proposed circuit does not need one more active component for the unity-gain inverting of the input signal in each filter realization.

Predicting heroin potency from the analysis of paraphernalia: A tool for overdose prevention projects

In recent years, fatal and non-fatal heroin-related overdoses have increased in northeastern Italy, and the change in potency of heroin available at street level has been identified as a prominent factor associated with acute toxicity. Two very different products, high-potency and low-potency heroin were becoming available on the street, and no clear morphological characteristics could be used to easily distinguish them. A theoretical model for predicting heroin potency from rapid analysis of cigarette filters was developed as part of an overdose prevention project. The model was derived from the analysis of real heroin samples and exploits the common presence of caffeine in heroin as an adulterant. It was tested on laboratory prepared filters, real filters used to prepare heroin injections, and other paraphernalia. The model showed strong predictive ability and was used to implement a rapid alert system to inform drug users and healthcare institutions about the potency of heroin or other psychoactive substances circulating in the area. Cigarette filters were used as standard material, but other paraphernalia were successfully tested. The developed model is a dynamic tool whose parameters can be updated according to the market characteristics, so it can be useful for laboratories involved in drug analysis and similar prevention programs.

Review of interferometric synthetic aperture sonar interferometric phase filtering methods

Interferometric synthetic aperture sonar (InSAS) is a novel three dimensional underwater mapping system, which is widely used in various fields. Interferometric phase filtering is a crucial process in InSAS signal processing. The study of interferogram filtering method has great significance to improve the signal-to-noise ratio (SNR) of interferogram, reduce the difficulty of phase unwrapping, and improve the accuracy of digital elevation maps. Firstly, this article introduces the sources of interferometric phase noise. Secondly, it illustrates the difference between real domain filter and complex domain filter by simulation experiment. Thirdly, the various methods of InSAS interferogram filtering are systematically studied, which can be classified into spatial domain filtering and transform domain filtering. The transform domain filtering can be further divided into frequency domain and wavelet transform filtering. Moreover, the advantages and disadvantages of various methods are analyzed theoretically. Finally, numerical simulation and real-data processing experiments are performed, and the advantages and shortcomings of several methods are compared using residue numbers, root mean square error (RMSE), and CPU time as evaluation criteria.

Adjustable fiber structure design for precise aerosol filtration

High-efficiency particulate air (HEPA) filters are widely used to filter aerosols. Predicting a HEPA filter's performance is essential to guarantee occupant health and comfort. Traditional cell models do not consider the fiber diameter distribution and spatial orientation, which makes them unable to predict filter performance well. We use the computational fluid dynamics (CFD) method to realize the initial performance simulation of glass-fiber (GF) filter media based on a random 3-D fiber model. In this study, we divided the filter media into multiple independent zones in the thickness direction and generated a fiber structure with the same fiber diameter distribution as the real filter media. Based on this method, we investigated the stability of the model and the effects of parameters such as computational domain width, fiber windward angle, filtration velocity, and fiber diameter distribution on the filtration performance of the filter media. The simulated pressure drop is in good agreement with the experimental values, and the efficiency of the most penetrating particle size (MPPS) of the filter media can be accurately calculated. A fiber model design and performance comparison of different fiber diameter distributions are realized. We believe this method can help us better understand the particle capture process and design a fiber structure for filter media to obtain better performance.