Top Filter Research Articles

Distribusi Nitrogen pada Budidaya Ikan Koi (Cyprinus Rubrosfuscus) dalam Sistem Vertiqua Menggunakan Biofikal Filter Atas

Vertiqua is an innovation in vertical cultivation on limited land and water. Vertiqua continues to be developed to be effective in cultivating fish. This research aims to examine the effectiveness of nitrogen distribution in vertiqua using biofical top filters. The analysis used is quantitative analysis by calculating and testing the data that has been collected. Total nitrogen feed input, total nitrogen wasted, and percentage of nitrogen absorption were calculated using existing formulas. Comparative testing using the T – test on the Mini Tab application was carried out to test the effectiveness of nitrogen absorption. The research results showed that nitrogen absorption in the vertiqua using the top biofical filter was effective, ranging from 198,12 – 200,89 mg/l. Nitrogen absorption in the vertiqua without using a biofical top filter ranges from 42,75 – 43,35 mg/l. The distribution value of effective nitrogen absorption in vertiqua using the top biofical filter is shown by a P value <0,05. Vertiqua with a biofical top filter is also able to reduce nitrogen levels so that fish survival is good.

Struktur Komunitas Fitoplankton pada Budidaya Ikan Koi (Cyprinus Rubrosfuscus) dalam Sistem Vertiqua Menggunakan Biofikal Filter Atas

Vertiqua biofical top filter is a cultivation technique with a recirculation system that utilizes limited land. Vertiqua is a solution for cultivation. When cultivating koi fish in vertiqua, the feed capacity increases and there is a high nutrient load so that the waters are easily polluted, therefore the presence of an upper biophysical filter can reduce pollution. This is important to study, especially the structure of the phytoplankton community because it is one of the biological indicators of ponds in koi fish cultivation. This research was carried out for 6 weeks in Sindangpalay Ciberem Sukabumi. The research was carried out by taking phytoplankton in the vertiqua at intervals of once every 2 weeks. The data analysis in this research is abundance, diversity, uniformity and dominance. During the research results obtained were abundance 636-673, diversity 2.6, uniformity 0.9, and dominance 0.01. The water quality studied was ammonia, nitrate, nitrite, phosphate, pH, DO, turbidity and temperature. These waters are stable and healthy, which is a positive indicator to support fish farming activities. The water quality in Vertiqua is classified as good and the ecosystem is balanced, these waters are ideal for supporting the productivity and health of farmed fish.

VARDHMAN ENVIROTECH: CREATING BLUE OCEAN AND REINVENTING BUSINESS MODEL

Vardhman Envirotech (VE), a startup offering services and solutions in the field of rainwater harvesting, was started by Amit Doshi (Doshi). Doshi, a first-generation entrepreneur, started VE in June 2014 which generated revenues through consulting, selling rain top filter (RTF), selling injection recharge well (IRW) solutions and installation of IRW. VE entered B2B segment in 2017 with IRW and has expanded operations in India and abroad. VE created IRW through value innovation and the company has been successful in installing over 2,300 IRW by 2021. The case provides an opportunity for students to step into the shoes of Doshi and plan a way forward for the future growth of the company. Students have to also reflect on the journey covered so far by Doshi which followed value innovation and reinvented business model. In doing so, students should take into consideration the data regarding the water crises in India and outside India.

Near-flat top bandpass filter based on non-local resonance in a dielectric metasurface.

Localized light matter interaction at a resonant nanostructure facilitates spectrally selective transmission of light, which has led to demonstrations of ultrathin metasurface based optical filters. Unfortunately, due to the nature of Lorentzian spectral line shape in such resonances, it is inevitable to suffer significant spectral crosstalk. In this work, we demonstrate a conceptually new type of spectral filter which exhibits near flat-top bandpass with minimized spectral overlaps. To realize this, we leverage the recent development of non-local resonance in dielectric nanostructure to design a double-layered optical filter with performance comparable to the ideal spectral filters. The designed metasurface shows averaged transmission of more than 90% across the target spectral band and suppressed transmission of less than 10% out of the spectral band.

Color gamut change by optical crosstalk in high-resolution organic light-emitting diode microdisplays.

Herein, the color gamut change by optical crosstalk between sub-pixels in high-resolution full-color organic light-emitting diode (OLED) microdisplays was numerically investigated. The color gamut of the OLED microdisplay decreased dramatically as the pixel density of the panel increased from 100 pixels per inch (PPI) to 3000 PPI. In addition, the increase in thickness of the passivation layer between the bottom electrode and the top color filter results in a decrease in the color gamut. We also calculated the color gamut change depending on the pixel structures in the practical OLED microdisplay panel, which had an aspect ratio of 32:9 and a pixel density of 2,490 PPI. The fence angle and height, refractive index of the passivation layer, black matrix width, and white OLED device structure affect the color gamut of the OLED microdisplay panel because of the optical crosstalk effect.

Evaluation of color-based classical conditioning as feeding stimuli in common carp, Cyprinus carpio

This study was conducted to evaluate the application of classical conditioning using light and color as a feeding trigger for common carp (Cyprinus carpio). Common carp (average size 38.8 g, stocking density ten fish/tank) was reared in a 120 l glass aquarium equipped with a top filter, thermostat, and aeration. The designated treatment that used in this study is (1) CTRL treatment whereas color, light position, and feeding position assigned randomly (2) FEED treatment whereas green color was associated with feeding (3) FEEDxSTRESS treatment whereas green color was associated with feeding and red color were associated with stress by giving disturbance in the tank for a short period of time (4) negative control whereas no treatment was given. To evaluate feeding responses, we observe time required for 80% of fish to gather in the feeding area (T80%), the number of fish gather around in the feeding area at 5 seconds after LED that associated with feeding was switched on (DF5s), and total feed intake of the fish. Using two-way ANOVA, the result shows improvement in T80% of FEED treatment compared to initial measurement (178 s vs. 85 s, P=0.012), while no difference was found in DF5s and feed intake.

Tracking Multiple Vehicles Constrained to a Road Network From a UAV with Sparse Visual Measurements.

Multiple-target tracking algorithms generally operate in the local frame of the sensor and have difficulty with track reallocation when targets move in and out of the sensor field-of-view. This poses a problem when an unmanned aerial vehicle (UAV) is tracking multiple ground targets on a road network larger than its field-of-view. To address this problem, we propose a Rao-Blackwellized Particle Filter (RBPF) to maintain individual target tracks and to perform probabilistic data association when the targets are constrained to a road network. This is particularly useful when a target leaves and then re-enters the UAV’s field-of-view. The RBPF is structured as a particle filter of particle filters. The top level filter handles data association and each of its particles maintains a bank of particle filters to handle target tracking. The tracking particle filters incorporate both positive and negative information when a measurement is received. We implement two path planning controllers, receding horizon and deep reinforcement learning, and compare their ability to improve the certainty for multiple target location estimates. The controllers prioritize paths that reduce each target’s entropy. In addition, we develop an algorithm that computes the upper bound on the filter’s performance, thus facilitating an estimate of the number of UAVs needed to achieve a desired performance threshold.

Development and Demonstration of Pilot Scale Metal-Air Flow Battery for Ultra-Large Capacity Energy Storage System

Recently, novel concepts of electrochemical cells have been spotlighted for ultra-charge energy storage system. Among these cells, magnesium alloy (AZ31) air batteries have attracted much attention as promising energy conversion devices due to their high theoretical energy density, eco-friendly materials and low fabrication cost. Although AZ31–air battery is a primary battery, the AZ31–air battery can be re-used or recharged mechanically by replacing the consumed AZ31 anode and turbid electrolyte with a fresh AZ31 anode and electrolyte, refering to “re-fuelable” During the discharge process, the AZ31 anode is oxidized to ionized Mg, producing two electrons, while at the opposite carbon air-cathode, oxygen molecules pass through the gas diffusion layer and is then reduced to OH− by reaction with H2O and electrons. The theoretical voltage of the AZ31–air battery is 1.2 V and the specific energy density is 2.2 kW h kg−1. Though AZ31–air batteries have a relative high voltage and energy density, there are still scientific problems limiting their pilot scale application. The main issue of cell is the high polarization and low coulombic efficiency. These problems are caused by the corrosion of the metal anode arising from the reaction of metal ions and the electrolyte, and the sluggish by-product kinetics in the air-cathode. In this work, we combined Mg-air batteries with electrolyte flow system, called metal-air flow battery (MAFB) in order to enhance the discharge properties and lifetime by solving the sluggish by-product problems. The components of anode and electrolyte were AZ31 (magnesium alloy) as a fuel and 18wt% saline aqueous solution. The circulation of electrolyte flow efficiently reduces the coagulation of Mg(OH)2 by-product in the unit-cells. As a result, the anode surface efficiency has increased from 72 to above 90 % after the use of flow system. In addition, we have successfully design and developed the metal-air flow battery from unit-cell to rack system. The rack system is made up of 25 series of electrically wired unit-cells for modules and 4-level of modules with electrolyte flow system. The flow system conducted simultaneously in each unit-cells by electrolyte supply tank in the top and by-product filter tank in the bottom. From the rack system, a pilot scale MAFB with 400 pieces of unit-cells was developed and fabricated for ultra-large energy storage system. The 704 kWh of energy storage system demonstrated by 25s-16p electrical wiring with 4-rack flow systems. As a result, it is the first report about the MAFB using AZ31 anodes in pilot-scale energy storage system. It has shown a large potential for future energy conversion devices for smart grid applications. Figure 1

Development and Validation of a Simple Bioaerosol Collection Filter System Using a Conventional Vacuum Cleaner for Sampling

Although numerous bioaerosol samplers for counting and identifying airborne microorganisms are available, the considerably high purchase and maintenance costs for the sampler often prevent broad monitoring campaigns for occupational or environmental surveillance of bioaerosols. We present here a newly developed simple adapter and filter system (TOP filter system) designed to collect bioaerosol particles from a defined air volume using conventional vacuum cleaners as air pumps. We characterized the physical properties of the system using air flow measurements and validated the biological performance. The culture-based detection capacities for airborne fungal species were compared to a standard impaction sampler (MAS-100 NT) under controlled conditions in a bioaerosol chamber (using Trichoderma spores as the test organism) as well as in the field. In the chamber, an overall equivalent detection capacity between all tested filters was recorded, although a significant underrepresentation of the TOP filter system for Trichoderma spores were seen in comparison to the MAS-100 NT. In a comparative field study (n = 345), the system showed similar biological sampling efficiencies compared to the MAS-100 NT impactor, only the diversity of identified fungal communities was slightly lower on the filters. Thus, the system is suitable for large-scale environmental sampling operations where many samples have to be taken in parallel at a given time at distant locations. This system would allow endeavors such as antibiotics resistance monitoring or hygiene surveys in agricultural or occupational settings.

Products of Interest

Products of Interest

67‐4: Shutter‐Free Full Colour Solid State Reflective Display (SRD®)

We demonstrate for the first time a simplified thin‐film optical architecture that results in a fully bistable, full‐colour, video‐capable SRD frontplane without the need for top shutters or optical filters. The expected performance of the new architecture is quantified using simulations and initial experimental results shown on non‐pixelated, continuous films.

Acousto-optic tunable flat top filter based on one-dimensional coupled-cavity photonic crystals

In this paper, an acousto-optic tunable flat top filter is proposed by using one-dimensional coupled-cavity photonic crystal, and two kinds of materials, i.e. magnesium fluoride and tellurium dioxide, are selected. Based on the theory of acousto-optic effect, the thickness and refractive index of one-dimensional coupled cavity photonic crystal acousto-optic medium are changed by varying the ultrasonic frequency. After the parameters of acousto-optic medium are changed, the central wavelength of flat top filter of transmission spectrum shifts toward the short wave direction, thus realizing tunable filtering function. Based on the transfer matrix method and the theory of acousto-optic effect, the theoretical model of the flat top filter is established. The rectangularity, passband bandwidth, insertion loss and tunability of flat top filter are simulated by COMSOL software. The results show that the tuning effect can be achieved by applying a certain frequency of ultrasound in the case of different ultrasonic amplitudes. The decreasing trends of transmittance are basically identical in the process of changing ultrasonic frequency in the case of different amplitudes. When the central wavelength of the flat top filter increases from 1510 nm to 1514 nm, the transmissivity corresponding to the central wavelength increases sharply from 37% to 90%; when the central wavelength of the flat top filter continuously increases to 1562 nm, the transmittance corresponding to the central wavelength increasing gently from 90% to 97% in the case of different amplitudes. Considering the transmissivity required to exceed 90% in the passband of flat top filter and the cost of ultrasonic generator, the ultrasonic wave with an amplitude of 0.4 nm is selected as the research object. The flat top filter with 5–6 nm central wavelength and 1514–1562 nm tunable flat top filter can be realized by applying ultrasonic wave with the frequency in a range of 6–11 MHz. In the tunable range, the highest insertion loss is only 2.23 dB, the lowest is only 0.78 dB, and the lowest rectangularity is 1.4. In a practical flat top filter with machining error within 5 cm, the deviation of center wavelength, rectangularity, insertion loss and passband bandwidth of flat top filter are all very small. The flat top filter has the characteristics of easy design and integration, flat passband, wide tunable range, stable passband bandwidth, low insertion loss and high quality factor. It has important applications in optical communication fields such as optical switch, tunable fiber laser and fiber sensing.

First Steps Towards a Formalization of Forcing

We lay the ground for an Isabelle/ZF formalization of Cohen's technique of forcing. We formalize the definition of forcing notions as preorders with top, dense subsets, and generic filters. We formalize a version of the principle of Dependent Choices and using it we prove the Rasiowa-Sikorski lemma on the existence of generic filters.Given a transitive set M, we define its generic extension M[G], the canonical names for elements of M, and finally show that if M satisfies the axiom of pairing, then M[G] also does. We also prove that M[G] is transitive.

The Boss Knows Best: Directors of Research and Subordinate Analysts

Research departments are managed by directors of research (DORs). Subordinate analysts working for higher-quality DORs provide superior earnings forecasts that elicit stronger market reactions, provide better investment recommendations, and have better career outcomes. For the broker, higher-quality DORs drive more trading commissions. Economically, analysts benefit the most from DOR–analyst industry alignment resulting from DORs’ former analyst experience. We provide several tests to mitigate endogeneity concerns and explore various mechanisms to explain these results. Overall, our article identifies a unique channel whereby the industry-specific and general human capital of top management filters through to individual subordinates and consequently improves organizational performance.

Image fusion for MODIS and Landsat images using top hat based moving technique with FIS

The image fusion technique is widely used in various applications like military, remote sensing, security and medical imaging. In image fusion, two different images with similar index is fused to extract the exact information. The Landsat and Moderate resolution imaging spectroradiometer images taken from artificial satellite are not perfectly distinguishable. The principal component analysis, discrete cosine transform and discrete wavelet transform with spatial frequency are the existing methods used for fusing images. The principal component analysis and discrete cosine transform were applicable only for low precision and low quality applications. Also, the output image faced drawbacks that resulted in blurred image with low recognition rate. In order to obtain image clarity and accuracy, the top hat based moving technique with fuzzy inference system is proposed in this paper. The white top hat and black top hat techniques filter the light and dark character of the image. Then the fusion is performed by fuzzy inference system. The proposed method is used to retrieve satellite images which are highly informative and the image clarity is also high since the entropy value of the proposed method is high when compared to other conventional techniques. The proposed method has higher PSNR value compared with the state-of-the-art techniques which indicates the proposed fused image has good quality.

IMPACT OF NURSERY USING DIFFERENT PHYSICAL FILTRATION SYSTEM ON HEMOLYMPH GLUCOSE LEVEL AND SURVIVAL RATE OF SPINY LOBSTER JUVENILE Panulirus homarus

The problems in culture of early juvenile phase of spiny lobster Panulirus homarus is low survival rate of the seed. One of strategies to improve production is using filtration system during nursery of spiny lobster. The aim of this study to evaluate differentation of physical filtration system on responsse stress and survival rate of juvenile P. homarus. Experimental design of this study consisted of four treatments and two replications. The treatments were using flow through system without protein skimmer and filter (K), filtration system with protein skimmer (SK), filtration system with top filter (F) and filtration system with combinations of protein skimmer and top filter (SKF). P. homarus with initial weight 0.18+0.01 g were cultured for 60 days with density 250 lobster/tank. During maintenance, P. homarus were fed trash fish with feeding rate 20% of body weight. Parameters of glucose hemolymph were evaluated to determine stress response. Stress response was determined at day 0, 6, 20 and 60. Parameters of survival rate were determined at the end of experiment. The result showed that the treatment of filtration system with combination of protein skimmer and top filter (SKF) decreased stress responsse by decreasing glucose hemolymph of juvenile P. homarus during maintenance. Survival rate also higher (P<0.05) in treatment SKF (33.2%) than other treatments. It is concluded that SKF was the best physical filtration system for juvenile period of spiny lobster P. homarus Keywords: filtration system, glucose hemolymph, spiny lobster, survival rate

An improved discriminative filter bank selection approach for motor imagery EEG signal classification using mutual information

BackgroundCommon spatial pattern (CSP) has been an effective technique for feature extraction in electroencephalography (EEG) based brain computer interfaces (BCIs). However, motor imagery EEG signal feature extraction using CSP generally depends on the selection of the frequency bands to a great extent.MethodsIn this study, we propose a mutual information based frequency band selection approach. The idea of the proposed method is to utilize the information from all the available channels for effectively selecting the most discriminative filter banks. CSP features are extracted from multiple overlapping sub-bands. An additional sub-band has been introduced that cover the wide frequency band (7–30 Hz) and two different types of features are extracted using CSP and common spatio-spectral pattern techniques, respectively. Mutual information is then computed from the extracted features of each of these bands and the top filter banks are selected for further processing. Linear discriminant analysis is applied to the features extracted from each of the filter banks. The scores are fused together, and classification is done using support vector machine.ResultsThe proposed method is evaluated using BCI Competition III dataset IVa, BCI Competition IV dataset I and BCI Competition IV dataset IIb, and it outperformed all other competing methods achieving the lowest misclassification rate and the highest kappa coefficient on all three datasets.ConclusionsIntroducing a wide sub-band and using mutual information for selecting the most discriminative sub-bands, the proposed method shows improvement in motor imagery EEG signal classification.

Effectiveness of table top water pitcher filters to remove arsenic from drinking water

Arsenic contamination of drinking water is a serious threat to the health of hundreds of millions of people worldwide. In the United States ~3 million individuals drink well water that contains arsenic levels above the Environmental Protection Agency (EPA) maximum contaminant level (MCL) of 10 μg/L. Several technologies are available to remove arsenic from well water including anion exchange, adsorptive media and reverse osmosis. In addition, bottled water is an alternative to drinking well water contaminated with arsenic. However, there are several drawbacks associated with these approaches including relatively high cost and, in the case of bottled water, the generation of plastic waste. In this study, we tested the ability of five tabletop water pitcher filters to remove arsenic from drinking water. We report that only one tabletop water pitcher filter tested, ZeroWater®, reduced the arsenic concentration, both As3+ and As5+, from 1000 μg/L to < 3 μg/L, well below the MCL. Moreover, the amount of total dissolved solids or competing ions did not affect the ability of the ZeroWater® filter to remove arsenic below the MCL. Thus, the ZeroWater® pitcher filter is a cost effective and short-term solution to remove arsenic from drinking water and its use reduces plastic waste associated with bottled water.

Abstract 2912: Size based enrichment and sorting of Ov90 cancer cells and clusters with a new multistage filtration cartridge reveals distinct phenotypes

Abstract Background: Circulating tumor cells (CTCs) are released in blood from the primary tumor, but although very heterogeneous both in size and marker expression, are very rare and provide information not available from the primary tumor. The identification of CTC cells and clusters could advance our understanding of metastasis and help personalize therapy.1,2 Notably, CTC clusters were shown to have a higher metastatic potential than single cells3 but the process remains poorly understood. We present a multistage filtration system with pore sizes from 20 down to 8 μm for the size-selective enrichment of Ov90 ovarian cancer cells and clusters from blood. Each captured cell population was released, cultured and characterized independently. Methods: We developed a 3D printed multistage filtration cartridge and polymer filters with 20, 15, 12, 10 and 8 μm-diameter pores. Filters were stacked from 20 (top) to 8 μm (bottom) and used to enrich and sort Ov-90 cells spiked in 1:6 mL of blood:PBS. Captured cells were released by removing individual filters from the cartridge, reverse flowing OSE medium, and then cultured separately. Results: Ov-90 clusters were found mostly on the top filter (20 μm) and interestingly, few small clusters (3-4 cells) were found on the 8 and 10 μm filters, suggesting alignment of cluster cells as they pass through the pores.4 Cell and nucleus diameters were measured, and a general correlation was found between filter pore size and cell and nucleus size. Interestingly, nucleus size was found to be the single most significant parameter in determining passage of single cells and small clusters through pores. Following cell culture, two distinct phenotypes were observed: cell captured on small pore filters (8-12 μm) grew primarily in a monolayer. Cells captured on filters with larger pores (15-20 μm) first grew as monolayer, but rapidly formed cell aggregates that subsequently detached from the surface. Staining for E-Cadherin, a cell-cell adhesion protein, revealed a loss of expression of cells from filter with larger pores. Conclusion: We developed a new multistage filtration method and selectively enriched and sorted cells based primarily on their nucleus size. We identified two Ov-90 populations with different growth behaviors with low E-cadherin expression on the cells forming clusters, which is known to correlate with metastasis. The application of multistage filters may also reveal different CTC populations based on nucleus and cell size.

Bionic RSTN invariant feature extraction method for image recognition and its application

It is significant to extract rotation, scaling, translation, and noise (RSTN) invariant features inspired by biological vision for image recognition. A bionic RSTN-invariant feature extraction are proposed. This extraction process comprises two stages. In the first stage, a novel orientation edge detection is designed based on a filter-to-filter scheme. Gabor filters, a bottom filter, smoothen an image by simulating biological vision. Bipolar filters, a top filter, detect the horizontal and vertical direction orientation edge by simulating vision cortex response. After obtaining the orientation edge of the image, an interval detector is executed by a spatial frequency of different direction and distance. Then, the interval detection results are transformed into pixels of the orientation-interval feature map. RSTN invariant features are generated through the repetition of orientation edge detection and interval detection. Several experimental results demonstrate that RSTN-invariant features have striking robustness, and capable to classify RSTN images. Finally, bionic invariant features are practiced in traffic sign recognition.