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Two-dimensional optical image edge enhancement is investigated using a spatial acousto-optical (AO) filter operating at two wavelengths of optical radiation, which significantly increases the reliability of measurements and also reduces the effect of noise. The filter operates basing on diffraction of light in two diffraction orders. It is shown that, in the general case, it is impossible to obtain a two-dimensional image contour simultaneously at two wavelengths at the same energy and frequency-angular parameters of the AO filter. A regime has been found that makes it possible to switch from one wavelength to another while maintaining the operation of edge enhancement by changing the acoustic power. This regime has been experimentally confirmed by the example of the formation of a two-dimensional image contour using two-colour radiation of an Ar laser emitting at wavelengths of 0.488 × 10−4 and 0.514 × 10−4 cm, and an AO cell made of TeO2, operating at a sound frequency of 57 MHz.

We demonstrate a structure for a vertical-cavity surface-emitting laser (VCSEL) with a mode filter and half-wavelength (λ/2) cavity. The effects of λ/2- and λ-cavities on the threshold current are studied. The thickness and etched diameter of the mode filter are optimised to achieve single-transverse-mode output. The results show that when changing from λ-cavity to λ/2-cavity, the threshold current of the VCSEL decreases by 30.7% (from 0.85 mA to 0.65 mA). In addition, for the mode-filter thickness of 80 nm, and the etched diameter of 2.5 μm, the side mode suppression ratio reaches 90 dB, which meets the requirement of single-transverse-mode output. The VCSELs with the optimised design can overcome many difficulties and have great potential in 3D face recognition.

A cold preamplifier based on superconducting quantum interference devices (SQUIDs) is currently the preferred readout technology for the low-noise transition edge sensor (TES). In this work, we have designed and fabricated a series SQUID array (SSA) amplifier for the TES detector readout circuit. In this SSA amplifier, each SQUID cell is composed of a first-order gradiometer formed using two equally large square washers, and an on-chip low pass filter (LPF) as a radio-frequency (RF) choke has been developed to reduce the Josephson oscillation interference between individual SQUID cells. In addition, a highly symmetric layout has been designed carefully to provide a fully consistent embedded electromagnetic environment and achieve coherent flux operation. The measured results show smooth V–Φ characteristics and a swing voltage that increases linearly with increasing SQUID cell number N. A white flux noise level as low as 0.28 μ Φ 0/Hz1/2 is achieved at 0.1 K, corresponding to a low current noise level of 7 pA/Hz1/2. We analyze the measured noise contribution at mK-scale temperatures and find that the dominant noise derives from a combination of the SSA intrinsic noise and the equivalent current noise of the room temperature electronics.

This work investigates the applicability of using data from personal monitoring dosimeters to assess photon energies to which medical workers were exposed. Such determinations would be important for retrospective assessments of organ doses to be used in occupational radiation epidemiology studies, particularly in the absence of work history or other information regarding the energy of the radiation source. Monthly personal dose equivalents and filter ratios under two different metallic filters contained in the Luxel+® dosimeter were collected from Landauer, Inc. from 19 nuclear medicine (NM) technologists employed by three medical institutions, the institution A only performing traditional NM imaging (primarily using (99m)Tc) and institutions B and C also performing positron emission tomography (PET, using (18)F). Calibration data of the Luxel+® dosimeter for various Xray spectra were used to establish ranges of filter ratios from 1.1 to 1.6 for (99m)Tc and below 1.1 for (18)F. Median filter ratios were 1.33 (Interquartile range (IQR), 0.15) for institution A, 1.08 (IQR, 0.16) for institution B, and 1.08 (IQR, 0.14) for institution C. The distributions of these filter ratios were statistically-significantly different between the institution A only performing traditional NM imaging and institutions B and C also performing PET imaging. In this proof-of-concept study, filter ratios from personal monitoring dosimeters were used to assess differences in photon energies to which NM technologists were exposed. Dosimeters from technologists only performing traditional NM procedures mostly showed Al/Cu filter ratios above 1.2, those likely performing only PET in a particular month had filter ratios below 1.1, and those which showed filter ratios between 1.1 and 1.2 likely came from technologists rotating between traditional NM and PET imaging in the same month. These results suggest that it is possible to distinguish technologists who only worked with higher-energy procedures versus those who only worked with other types of NM procedures.

With its advantages of high velocity measurement accuracy and fast dynamic response, the laser Doppler velocimeter (LDVs) is expected to replace the odometer (OD) in combination with a strapdown inertial navigation system (SINS) to give a higher-precision integrated navigation system. Since a LDV has higher velocity measurement accuracy and data update frequency than an OD and Doppler velocity log, a LDV is used for the first time in this paper to aid a SINS in in-motion alignment. Considering that some approximation is used in the alignment model, the uncertainty noise of the sensors during the motion process and the unknown noise parameters during the filter process, an adaptive unscented quaternion H-infinite estimator (AUSQUHE) is proposed. The proposed AUSQUHE method has high robustness since it combines the advantages of an unscented quaternion estimator and H-infinite filter. The adaptive threshold of the H-infinite filter and the adaptive measurement noise covariance matrix are introduced to make the filter adapt to the changing environment and accelerate the convergence of errors. The performance of the proposed method is verified by a vehicle field test with a normal LDV signal and a vehicle test with the LDV signal disturbed by noise. The results show that the proposed method has higher alignment accuracy, faster convergence speed and stronger robustness than the four other compared methods.

We proposed a technique of tunable plasma narrow-band filter (PNBF) to generate high-power narrow-band pulses based on a plasma mirror and pulse chirp. PNBFs have an ultra-wide free spectral range, high damage threshold, and accurate wavelength-tunable function, and tunable sub-nanometer pulses could be achieved by controlling the pulse chirp. The feasibility of the proposed technique was verified by both simulation and experiment. Three ~0.6 nm bandwidth pulses centered at different wavelengths were obtained respectively, maintaining good near and far-field beam quality. PNBF is expected to be an effective technique for high-power tunable narrow-band pulse generation with high-power ultrafast lasers.

We propose a new concept of an active narrowband filter based on a 2.5D metasurface from Ge2Sb2Te5 (GST). In this paper, we present a numerical calculation of the transmission spectrum from a structure of ellipsoids of revolution. For this 2.5D metasurface, modulation of narrow peaks in the IR range for s- and p-polarization is shown. A manufacturing technique using two-photon lithography and laser electrodispersion is proposed.

The influence of plasmonic nanoparticles embedded in the central and side layers of the frustrated total internal reflection filter on the resonant transmission of light is analyzed. It is shown that the frequency dispersion causes the splitting of the filter bandwidth and the angular splitting of the incident beam into several output beams.

Simple substrates for surface enhanced Raman spectroscopy (SERS), producible in a cost-efficient way, are of growing interest both for scientific and for environmental applications. In this study, we demonstrate the use of three types of bio-based tannin-furanic rigid foams as precursor materials for SERS substrates. Coated with a silver layer, these substrates allowed the detection of several well-known analytes in the mM regime by Raman spectroscopy. Specific optimization of the standard tannin-furanic foam morphology by tuning the chemical synthesis led to a smaller and more homogeneously distributed pore structure, supplying more active hot spot areas. Thus, we obtained a significant increase and a lower relative standard deviation (RSD) of the SERS signal recorded over the mapped SERS substrate area, for several analytes, in particular for Malachite Green dye. This work represents a feasibility study opening several potential applications of this biopolymers in fields such as the detection of water pollutants, virtually combining filtration and SERS capabilities driven by a controlled porosity.

One of the main parameters for the design of cigarettes is filter ventilation. As filter ventilation increases, the concentrations of Tar, Nicotine and CO (TNCO) emissions decrease. This work examines the correlation between filter ventilation and TNCO emissions, using the data of the cigarettes notified in the French market. The average values of filter ventilation, pressure drop with open and close vents and also of TNCO emissions remain quite constant during the three years examined (2018-2020). A mathematical model linking the value of filter ventilation with the values of TNCO emissions is developed. According to this model, the values of filter ventilation estimated from this model show a very good agreement with the measured values in the case of cigarettes with filter ventilation higher than 50%. Now such model could be established for lower ventilation values. These results show that the proposed model can be effectively used to correlate filter ventilation with TNCO emissions, in the case of ventilation values higher than 50%.

In this work, a numerical simulation of the aerosol motion when flowing around a single porous filter fiber with a diameter of 5 mm is carried out. The fiber is formed by a set of microfibers in a random arrangement. The size of the microfibers varies from 0.1 mm to 0.5 mm. For each fixed size of microfibers, a fiber model with different porosity of the medium was created. The porosity ranged from 0.7 to 0.9. The calculations were carried out in the ANSYS software package (v. 19.0). Studies have shown that a porous filter fiber model provides the maximum deposition efficiency for highly inert particles is provided by a porous filter fiber model with a microfiber size of 0.1 mm and a medium porosity of 0.9.

Biomass gasification is a thermochemical conversion process of solid biomass into a gaseous fuel called producer gas that can be used to generate power and electricity. The producer gas consists of around 47% of Nitrogen (N2), 24% Carbon Monoxide (CO), 16% Carbon Dioxide (CO2), 12% Hydrogen (H2), and 1% Methane (CH4). However, Nitrogen (N2) content in the producer gas reduces its heating values as N2 acts as a diluent because of the low calorific value (LCV) of gas. This study aims to design a Nitrogen gas filter for capturing nitrogen gas from producer gas to increase the heating value of producer gas as fuel in combustion. The method to increase the heating value of producer gas will increase the number of combustible gases or reduce the composition of non-combustible gases in producer gas. The use of material name zeolite with its microporous structures able to adsorb nitrogen molecules and act as catalysts to chemical reactions. Zeolites 5A have a small pore highly efficient to adsorb nitrogen gas because pore diameter is relatively similar to the size of nitrogen molecules. The quality of the producer gas depends on the design and operating parameters of the zeolite catalyst. Nitrogen Gas Adsorption Filter is a new method that has to be designed to improve the previous producer gas quality. Nitrogen Gas Adsorption Filter consists of a cylindrical shape body packed with crushed zeolites 5A. When this method of adsorption process is applied, the heating value of the producer gas is increased by observing the quantity of blue flame colour produced by NgAF.

The study on the fore-arc sedimentary basin for hydrocarbon exploration is rare because of the more complicated geological structures, and conventional seismic methods cannot optimally penetrate the rock layers as there are many volcanic and limestone rocks. One of the natural resources potential in the Southern part of the East Java region, especially in Malang and its surrounding areas is the possibility of hydrocarbons in the fore-arc basin, so research is needed to know the existence of these sedimentary basins. The gravity method is one of the geophysical methods used to assess sedimentary basins based on physical parameters of mass density. The aims of this research are to delineate the sedimentary sub-basin, to find out its structure pattern, interpret subsurface geological and basement configuration. The data analysis approach used in this study involves spectral analysis, upward continuation filter, and 3D inverse modeling. The maximum height for the optimum upward continuation filter is 3000 m, which results in regional and residual anomalies. There were five sedimentary sub-basins identified based on residual gravity anomaly, and the gravity anomalies can also detect structure patterns such as basement high, lineament, and fault pattern. The bedrock is supposed as an intermediate igneous rock with a mass density of around 2.7 gr/cc according to the results of 3D inverse modeling. Deposition from bottom to upward is Mandalika, Nampol, and Wonosari Formations and completed by the uppermost are quaternary volcanic rocks. The inversion modeling results show that the Malang and surrounding areas have thick sedimentary rocks covered by volcanic deposits, which is impressive for further investigation to explore the possibility of the hydrocarbon existence in these areas.

A lot of properties depend on the quality of the surface, such as efficiency, reliability, functional properties, external appearance, and, last but not least, the cost of the entire production process. And if there is an inaccurate assessment during evaluating the integrity of the surface, especially for assessing roughness, this can lead to fatal problems in the actual use of the inspected part in practice. In order to meet all the requirements of the evaluation of the surface structure, it is necessary to keep up with the times and always have control of new possibilities and knowledge from the fields of measuring and evaluating the integrity of the surface, and being able to implement this knowledge into real conditions of use. In the area described in this article, the selection of software filters, this is not always the case. The main reason is low awareness and the great complexity of choosing a suitable combination of possible procedures and techniques for setting software filters. Therefore, a comprehensive methodology for the selection of software filters for both periodic surfaces and subsequently for aperiodic surfaces was created and is described in this article. Its coherence and graphical simplicity are prerequisites for quick understanding and easy implementation of the methodology in common practice. The methodology for the selection of the software filter has 4 steps for periodic surfaces and 5 for aperiodic surfaces, which help the user of the profilometer, whether contact or contactless, to correctly set the device. Furthermore, the methodology should ensure that two people measure the same, or at least in the order of hundredths of the same results (values), which currently is not quite the case.

Energy saving in technological processes of agro-industrial complex is an integral part of the development of a market economy, since nowadays there is a total interest of suppliers and consumers in economical energy supply. At present, the concept of electromagnetic compatibility in matters of power quality assurance covers almost any type of interaction between various devices and systems using electromagnetic phenomena, as well as the interaction of these systems with living organisms. There is an increasing need to analyze the impact of energy losses on energy efficiency in general and the need to analyze additionally arising losses caused by a sharp deterioration in the power quality readings. At present stage, more accurate information is required about the state of the electrical networks modes to determine the level of losses and reduce the commercial component of losses. In this situation, power systems require more accurate forecasts of the load of distribution networks in order to achieve excellence in operation, planning the development of networks and optimization of energy resources management, but the process of high-quality compensation remains rather complicated due to the growth of distortions in low-voltage distribution networks. In contrast to the existing solutions, the authors of the article offer to introduce into the method (algorithm) for controlling a compensation device the operation of forecasting the value of active power of non-stationary non-linear load on the forthcoming period of the supply mains voltage according to the results of monitoring the change in the active power of the load during the previous periods and statistical processing of the data obtained.

Renewable energies (RES) will receive higher attention in the future, and continuously increase the penetration rate in the power system to achieve low carbon goal. However, the volatility and intermittent nature of RES generation caused by the uncertainty of the weather have brought huge challenges to the safe and stable operation of the power system. IACs have become a substitute for traditional power plants to accommodate RES by changing their operating power. This paper proposes a control method based on the MA filter to smooth photovoltaic generation power fluctuations utilizing inverter air conditioners (IACs). The photovoltaic power data is filtered by the MA filter in real time firstly. An output power with little fluctuations and one power deviation with high frequency fluctuations are obtained. The power deviation with high frequency fluctuations will be smoothed by IACs, while the remaining power deviation will be smoothed by ESSs. The case studies show a smooth power output is obtained for the power system after filtering.

This paper introduces the properties of an elliptical filter and Butterworth filter characteristics when narrowband noise passes through them, which has the same behavior in both, traffic and stop range. The amount of ripple in each band can be adjusted independently as it has a faster gain transition between the pass and stop band, so a compression has been made between elliptical and Butterworth filters response to narrowband noise in order to find a new ways to increase their immunity to noise. MATLAB Simulink Software has been used as a simulations environment.

The article is devoted to the application of the Levinson filter for the formation of an input sample in the already existing methods for assessing forest fires. This will allow you to plan in advance measures to minimize the risks of fire hazardous situations. The properties of cross-correlation of elements of the matrix of transition coefficients are applied to find the matrix of transition coefficients. The article provides an example of testing the application of the Levinson filter in the form of an application program. The results described in the article make it possible to judge the applicability of the chosen method of forestry area management.

Based on 5G system, a cylindrical dual-mode resonator and filter are designed. The electric field distribution characteristics of each mode of the dual-mode resonator are analyzed by using high-frequency electromagnetic field simulation software. Based on the designed dual-mode resonator, through theoretical calculation and analysis, a 5G system dielectric dual-mode filter is designed by using the RF / microwave simulation software ADS/HFSS. The coupling between modes is realized by setting metal screw perturbation on surfaces. The effect of two coupled degenerate modes is equivalent to that of two coupled resonators, so that the number of resonators can be reduced while the resonant circuit remains unchanged. For example, two modes of a resonator can be used in a traditional n-section filter, the same physical space realizes the characteristic of 2n section filter, which greatly reduces the size of the filter. A 5G system dielectric filter is designed based on dual-mode resonator. The results show that in the pass-band (3.4 ∼ 3.5GHz), the return loss is more than 18db, the insertion loss is less than 0.3dB, the zero on the left side of the pass-band is 3.1716GHz, the zero on the right side of the pass-band is 3.8537GHz, the VSWR is less than 1.28. Transmission zeros are introduced on both sides of the pass-band, which improves the suppression ability out of pass-band. The 5G system dielectric filter has the advantages of low insertion loss, small size and good suppression performance out of pass-band. When applied to 5G wireless communication system, the anti-interference ability and stability of the system can be improved.

Mathematical properties of the ensquared energy functions for apodized point-spread function (PSF) are presented. An expression of ensquared energy for the apodized point Spread function of the optical system with a circular aperture was derived using a parabolic apodized filter with a different arrangement N =1, 2,3,4. The results obtained were discussed graphically.

This paper considers the relationship of the pressure drop at the filtration baffle of a hydrodynamic vibration filter with and without protective baffle for different operation parameters like baffle flowrate and filtration baffle rotation speed. The simulations were done using ANSYS CFX and nonlinear Darcy’s law.

Bio-retention filtration system is the leading water conservation strategy that makes use of biogeochemical technique within a vegetation ecosystem to retain soil moisture, purify and conserve storm water in urban cities. The present study was aimed at designing a bio-retention filter basin in Kharghar node of Navi Mumbai, Maharashtra, India. The analysis was carried out for both minor (5-year average recurrence interval) and major (100-year average recurrence interval) floods. Total discharge was computed using the rational formula and it was estimated as 0.023 m3/s for minor flood condition and as 0.037 m3/s for major flood condition. The maximum infiltration rate was computed as 0.0047 m3/s considering sandy loam soil as the filter media. A flow width of 1.6 m was considered in designing the bio-retention filter. 100 mm diameter polyvinyl chloride pipe was proposed as they are the best in terms of performance and have advantage over other pipes. No liner is required for filter according to the soil condition of Kharghar. A transition layer of 100 mm gravel was suggested to provide better efficiency and durability for the bio retention system. The vegetation for the bio-retention basin can be Doob or Bermuda grass (Cynodon dactylon) as it has the highest water retention capacity as per Indian conditions.

we have explored the tunable multichannel characteristics of one-dimensional (1D) plasma photonic structure in presence of static magnetic field applied externally parallel and anti-parallel to the direction of propagation under normal incidence. We have theoretically examined the transmission characteristics of the binary photonic design consisting of alternate layers of CaF2and magnetic cold plasma layers by means of transfer matrix method (TMM) which is amongst the one of the popular techniques for simulating 1D multilayer periodic structures based on MATLAB. The proposed structure possessN-1number of distinct transmission peaks, each of unit transmission called as transmission channels in transmission spectra for given the number of periodsN> 1. In this study N varies from 2 to 6 in steps of 1 to get 1 to 5 transmission channels respectively. Further we have also investigated how these transmission channels can be repositioned inside PBG by applying the static magnetic field (B) externally under right hand polarization (RHP) and lift hand polarization (LHP) configurations for givenNat B = 0T, 0.02T, 0.04T and 0.06T. The reason behind the existence of these transmission channels is due to the superposition of evanescent and propagating waves inside plasma and dielectric layers respectively. The existence of these transmission channels inside PBG is different from the transmission bands which are formed due to the interference of forward and backward propagating waves. Besides this the tuning sense of the transmission channels at fixed B applied parallel or anti parallel to direction of periodicity, by changing the angle of incidence corresponding to TE and TM polarization case has also been examined to get some more useful and interesting tunable multichannel characteristics of the current design which cannot be obtained in conventional PPCs.

The construction of 5G system is in the works. In order to improve the anti-interference and reduce the volumes of 5G system, it is important to design a filter with better filtering performance and smaller volume. At present, the research of 5G filter is almost base on metal resonator. This paper designs a ceramic dielectric resonator, and on the basis of the designed dielectric resonator, a 5G band dielectric filter is designed after theoretical calculation and analysis by using rf/microwave simulation software HFSS. The coefficients are realized by the distance between two resonators, and the Q value is realized by the distance between the input port and the first resonator. The results show that in the pass-band (3.4 ∼ 3.5GHz), the return loss is more than 15dB, the insertion loss is less than 0.35dB, and the VSWR is 1.62. The filter has the advantages of small insertion loss, small size and good rejection out of pass-band, which can be applied to 5G band wireless communication system with better suppression performance to improve the communication quality of the communication system.

We propose a tunable acoustic filter using superlattices constructed by random stacking of solid and fluid layers. Acoustic waves are localized in the random superlattices (RSLs) and the transmission rates substantially decay to 0 except for the resonance transmissions where the acoustic waves are delocalized. The transmission rates become unity for the resonance transmissions. The resonance frequencies depend on the layer thicknesses, and we can modulate the transmission spectra from transparent to opaque, and vice versa, modifying the layer thicknesses. We numerically illustrate the changes in the transport properties for the aluminum/water RSLs, and suggest to exploit the RSLs for the tunable acoustic filters.

In order to improve the operation efficiency of the turbine and reduce the failure rate of the equipment, this paper takes the inlet filter device of the turbine as the research object, comprehensively utilizes computer technology, machine learning, computer network and other technologies, and proposes a remote monitoring system of the turbine filter device based on industrial Internet cloud service and C/S architecture. The industrial process monitoring system is designed according to the actual situation of the industrial process. By connecting the system to the industrial Internet cloud service, the remote monitoring of the on-site running state and operation data of the equipment is realized. On this basis, the artificial neural network is proposed to realize the timely diagnosis and treatment of faults, and the operation and maintenance suggestions are put forward to improve the stability of equipment operation, reduce the maintenance cost of equipment, so as to improve the economic benefits of system operation and maintenance.

Domestic kitchen wastewater contains significant quantities of fat residues that may insist in blocking home and municipal sewers. This work was designed to remove fat residues from domestic kitchen wastewater using synthetic sawdust filter. Five samples were examined, where the first one was a control. Synthetic filter contained sawdust was used as a removal of fat residues from four different samples of domestic kitchen wastewater. The obtained results showed that the synthetic sawdust filter could remove highest quantities of fat residues having removing capacity ranging from 80.7 ± 5.6 % in sample 1 to 88.5 ± 5.8 % in sample 4. Also, it was found that the mean value of pH, Electric conductivity (EC) and Total dissolved solid (TDS) of domestic kitchen wastewater were significantly affected by filtration process compared with those of control sample. The mean value of pH ranged from 6.61 ± 0.32 in sample 4 to 6.9 ± 0.54 in sample 2. E.C. mean value was varied from 1400.2 ± 262.8 μS/cm in sample 4 to 2100.4 ± 426.5μS/cm in sample 2 while mean value of T.D.S. was lying between 1123.0 ±.142.3 mg/L in sample 4 and 1347.0 ± 210.6 mg/L in sample 2. It seems clearly that sawdust synthetic filter was not affected when it was used for several times with different kitchen wastewater samples and this finding would suggest that this synthetic filter may work efficiently and subsequently may have no significant effects on sewer obstruction phenomena. In addition, all examined wastewater variables (pH, EC, and TDS) in all sample were significantly declined.

This paper is based on the current status of research and development in the high performance air filters segment. This can be done by choosing an appropriate filter and operating it under optimized conditions. The present paper details the applicability of filters used in conjunction with metal screen for the purpose of classifying aerosol. In this paper, the analysis on applicability of centrifugal force for achieving enhanced collection efficiency without increasing the pressure drop has also been done. This paper endorses the proposition that the quality of air filters can be improved remarkably and suggests a methodology for achieving the same. The Hepa filter can capture with extraordinary efficiency of 0.01 ×10 -9 meter sized particles. The size of the Corona Virus Covid-19 is 125 nm. The preliminary study shows that covid-19 can become aerosolized and can remain in the air for hours. After analysis, the flow rate has been increased from an initial value of 21 E 4 m 3/s ( thickness 0.15 mm) to the optimized value of 92E4 m 3/s (thickness 0.91 mm) which is a significant increase of 338% i.e. 3.38 times from initial value. For optimizing the material porosity, it has been found that the filter shows the maximum performance at a porosity value of 0.95.

We present an analysis of the illuminance measurement results when a glass neutral density filter (ND Filter) inserted between light source and photometer. ND filters are widely used as an alternative solution in illuminance calibration systems to perform lower illuminance level which caused by inadequate length of the photometric bench. However, there are some variables that must be considered when inserting ND filters in illuminance measurement, one of which is the perceived color temperature of the light source which is influenced by the non-flatness profile of the filter’s spectral. This research was conducted by calculating correction factor for each ND filters, which contribute to illuminance error. Six different ND filters in the range of 1% to 49% are used in this experiment. Scanning the spectral distribution of filter are done to analyzing the change of color temperature of the light source as it passes through an ND filter, due to the lamp must correspond to Illuminant A. This research shows the illuminance measurement error can be up to 20% proportionality to the transmittance as the effect of using ND filters. The results of this study are expected to provide recommendations for the calibration laboratory, especially in illuminance meter calibration.

The optimization function of the filter compensating device has been determined, the purpose of which was the possibility of the harmonic distortion factor minimizing, the arguments of which are the power of individual filters. To analyze and compare the efficiency of the filter compensating device, quality indicators measurements of the electrical energy at an agricultural machine-building plant were made. Using the developed methodology for the filter-compensating devices optimal parameters calculating in the Mathcad software environment, the parameters selection and determination of two options of filter-compensating devices were made. According to the calculations, it was found that for the object under study, the most optimal, effective and economical device is a filter compensating one with a narrow-band filter tuned to the 5th harmonic and a wide-band filter of the 3rd order tuned to the 7th harmonic.

A phoxonic crystal structure with a full phononic and photonic band gap is designed in this study, which is capable of conducting sound waves and also light waves with transverse magnetic (TM) polarization. Materials used in the structures are nylon and molybdenum, both of which have adequate difference in refractive index and elastic constants. It is worth of noting that the filling factor is considered to be 28% in all of the structures, in order to ease of fabrication. The final phoxonic filter structure is obtained by the comparison of several phoxonic filter structures in a similar condition. Since it is difficult to coordinate light and sound in phoxonic structures, the proposed structure has some advantages compared to other filters. This structure shows the optical and acoustical transmission linewidths equal 3.8 KHz in phononic and 0.06 nm in photonic modes, respectively. Also, the output quality factor is 23699 in phononic and 21201 in photonic modes. Finite element, plane wave expansion, and finite-difference time-domain methods are utilized for simulation.

The overall aim of this search investigated the effect of DO, alkalinity, and pH on nitrification in biological aerated filter system BAFs. The laboratory experiments by three identical pilot-scales downflow of BAFs using three different sunken materials types, 0.78±0.60 mm activated carbon-based material bed, 0.95±0.58 mm sand-based material bed, and 3.28±2.14 mm ceramic particle-based material bed, as attached growth zone in the treatment of municipal wastewater. As results of the experiments showed that activated carbon-based material bed when the mean concentration of dissolved oxygen was 6.76±2.25 mg/L and the mean alkalinity concentration was 77.25±2.60 mg CaCO3/L and the mean pH value was 7.21±0.20 the mean nitrification efficiency has reached of 90.11%. In the sand-based material bed when the mean concentration of dissolved oxygen was 7.33±1.82 mg/L and the mean alkalinity concentration was 77.56±2.77 mg CaCO3/L and the mean pH value was 7.22±0.20 the mean nitrification efficiency has reached of 87.74%. In the ceramic particle-based material bed when the mean concentration of dissolved oxygen was 6.37±1.84 mg/L and the mean alkalinity concentration was 77.31±2.71 mg CaCO3/L and the mean pH value was 7.22±0.20 the mean nitrification efficiency has reached of 85.17%.

The removal of nitrogen compounds in wastewater is receiving wide attention and the effluent standards will be tougher in the near future. The overall aim of this article is a review of biological aerated filter systems BAFs for removal of the nitrogen in wastewater. The BAFs technology is based on the principle of biofiltration where can be operated either in an upflow or downflow mode depending upon the position of the influent feed, where the media which attached growth zone can be either denser than water to give sunken media or less dense than water to produce floating media. The BAFs combines biological treatment and ammonia-nitrogen and solids removal in one reactor unit, where accumulated solids are removed from the BAFs through backwashing.

In this paper, the concepts of multiset Boolean filter, multiset Boolean pseudofilter, anti-multiset Boolean filter, and anti-multiset Boolean pseudofilter are introduced. Also, the relation between multiset Boolean filter(pseudofilter) and some other types of multiset filters(pseudofilters) are given.

A single-stage ring resonator capable of introducing six modes within the ultra-wideband (UWB) passband is presented. The sextuple-mode resonator consists of three rings and three sets of stepped-impedance open stubs. Based on this sextuple-mode resonator, a UWB filter fed by the interdigital-coupling line (ICL) is designed. And we propose a two-round interpolation method to obtain the filter’s initial dimensions. The designed filter is fabricated on a double-sided YBCO/MgO/YBCO high-temperature superconducting (HTS) thin film for demonstration. The experimental results show that this UWB filter produces eight resonances in the passband eventually, which effectively improves the in-band reflection and the band-edge steepness. Moreover, the upper stopband performance is enhanced due to the transmission zeros (TZs) generated by the stepped-impedance open stubs and the ICL structure. The measured good performance verifies the practicability of the two-round interpolation approach, which can also be extended to other odd–even-mode filter designs.

In this paper, the effectiveness of using random forest algorithm in the big data is studied. The reason for choosing this algorithm is because of its effective results in many previous studies, so it was chosen. The random forest algorithm was applied to the big data Internet of Things (IoT) dataset, with size 150,000 instances. After applying the algorithm, it gave an Accuracy score of 99.976%, and this indicates the effectiveness of the random forest algorithm in the big data. This result made the researcher search for one of the ways that increases the value of Accuracy, knowing that it is an excellent result. And use a filter to remove frequent values, and this helps reduce data volume and keep related data. After applying the filter with the random forest algorithm, the Accuracy value appeared at 99.998%, which indicates that it improved the random forest algorithm’s performance in the big data.

Classification problem in biological Omics data has gained in popularity in recent years. In consideration of the high dimension of the Omics dataset, the importance of feature selection technology becomes apparent. Feature selection can not only improve the classification accuracy but also avoid overfitting which is a common issue in machine learning. There are three main categories of feature selection methods: filter methods, wrapper methods, and hybrid methods. Yet it is difficult for researchers to choose among them. In this study, we conducted a comprehensive comparison for filter methods, wrapper methods, and hybrid methods. Specifically, we selected information gain as the filter method, genetic algorithm, and binary particle swarms optimization as the wrapper methods, IG-GA and IG-BPSO as the hybrid methods for comparison. The experimental results show that the IG-BPSO, a hybrid method, has the highest classification accuracy among these feature selection methods on three Omics datasets.

The adsorption technique has proven a better solution to reduce emission in diesel engines. Activated carbon is taken as an adsorbent for the study to investigate the engine behaviour on its performance and emissions. The experimental setup along with testing of the emission for gas analysers as well as for smoke meters was performed. In this paper, the emissions from diesel engines are reviewed. To reduce the emissions from an automobile, experimental methods of adsorption using activated charcoal in diesel engines is set up. Activated carbon is one of the best adsorption materials due to its high porosity and capture capacity, when reacted with other reagents in order of activation. The measurement of emissions from the diesel engine is obtained using gas analyser and smoke meter, both before and after the installation of filter. After successive results obtained by using these devices, the performances of the devices and efficiencies of the filter used is compared. In this experiment, we can see that the filter (activated carbon) has efficiently reduces the value of HSU by 43.73% and K value by 48.94%. Hence, the overall efficiency of activated carbon used is about 46%.

Valley filter is a promising device for producing valley polarized current in graphene-like two-dimensional honeycomb lattice materials. The relatively large spin–orbit coupling in silicene contributes to remarkable quantum spin Hall effect, which leads to distinctive valley-dependent transport properties compared with intrinsic graphene. In this paper, quantized conductance and valley polarization in silicene nanoconstrictions are theoretically investigated in quantum spin-Hall insulator phase. Nearly perfect valley filter effect is found by aligning the gate voltage in the central constriction region. However, the valley polarization plateaus are shifted with the increase of spin–orbit coupling strength, accompanied by smooth variation of polarization reversal. Our findings provide new strategies to control the valley polarization in valleytronic devices.

In order to realize the establishment of the unknown terrain map in the indoor environment of the ROS wheeled mobile robot, this article uses Lidar, Raspberry Pi and other hardware to build the wheeled mobile robot, in the ROS environment, the robot is built by the URDF model, and the robot model is configured. Differential controller, keyboard control node, etc. Establish the simulation environment, use different simulation environments to visually simulate the robot, and simulate the two optimization algorithms in the SLAM algorithm to simulate the construction of the map. In order to explore the effect of SLAM’s different optimization algorithms on the construction of graphics, the SLAM algorithm based on filter and the SLAM algorithm based on graph optimization are introduced respectively. The robot is selected. After the robot is built, three different experimental environments are selected. A variety of map-building algorithms are used to experiment, comparing the effects of G-mapping algorithm and Cartographer algorithm to build maps in a small-scale, large-scale and multi-obstacle environment. Use the image processing software under the Linux system to analyse the map created by the robot in the experimental environment, measure the coordinates of the robot feature points in the created map by the number of pixels, and compare the actual coordinates of the location of the special point in the actual environment to evaluate Construction effect. By comparing the effects of the two algorithms on the contours of various obstacles when building a map, the effect of mapping in a multi-obstacle environment is evaluated. The results show that the SLAM graph-building algorithm based on graph optimization has a more stable graph-building effect.

Microtremor is recorded with a device that is very sensitive to subsurface soil vibrations, that unwanted noise frequency waves are often also included. For this reason, processing needs to be done using filters that can attenuate the noise. In the previous research, signal decomposition was performed using the Interpolated Finite Impulse Response (IFIR) filter and resulted attenuation at the desired frequency value. Using the MATLAB program, microtremor data are processed with IFIR filtering, smoothing, calculation of: Horizontal to Vertical Spectral Ratio (H / V) curve, natural frequency (f0) and standard deviation (σ). The same process was carried out using Butterworth, Gaussian, and Cosine filters as a comparison with the Geopsy program. As a result, the amplitude characteristics obtained can provide a value of f 0 < 2.5 Hz. The value of f0 obtained using IFIR filter is also stable, proven by the standard deviation ranging from σ = 0.009 - 0.83 Hz, with an average of σ = 0.132 Hz. In conclusion, the IFIR filter can provide a well-attenuated H/V curve according to the specified cutoff frequency, which was 2 Hz. The IFIR filter is also considered capable of being applied to the HVSR method Microtremor data. Lowpass IFIR filter can attenuate high-frequency noise in microtremor data.

The in-vehicle air quality has increasingly attracted the attention of people. Hence, air filter performance under actual work conditions demonstrates remarkable significance. It is verified that the electrostatic adsorption can dramatically enhance the fractional efficiency of small-particle pollutants without increasing the pressure loss; as regard a lack of fractional efficiency test on the filter during the whole life cycle in current standards, the paper studied the tendency of filter’s fractional efficiency variation in the whole life cycle and discovered that fractional efficiency of small particles decreased first after increase due to the shielding of electrostatic charge; the tests on different air speed and area of filtered paper were carried out, showing that increasing the area of filtered paper can significantly lower the pressure loss and increase the filtration efficiency, which is of vital significance to provide the reference for further improving the performance of cabin air filter.

The FeaTibOx catalyst was loaded into the pores of porous ceramic using impregnation method for removing nitrogen oxides with selective catalytic reduction (SCR) technology. The catalytic performance over FeaTibOx catalyst was studied in detail. The Fe6Ti1Ox catalyst displayed more than 95% NOx conversion within the range of 280 °C–400 °C, and still maintained 97% NOx conversion when 300 ppm SO2 and 10 vol.% water vapor were introduced at the testing temperature of 300 °C. The influence factors (including filtration velocity, NH3/NO mole ratio and oxygen concentration) for NOx conversion over Fe6Ti1Ox catalyst were also studied. The suitable NH3/NO mole ratio and oxygen concentration was 0.9 and 6%, respectively. The XRD, N2-BET, H2-TPR, NH3-TPD and XPS were employed to investigate physicochemical property of the FeaTibOx catalyst. The results illustrated that Fe6Ti1Ox catalyst has hematite Fe2O3 and TiO2 structure, better redox properties and stronger surface acid.