Commercial Filter Research Articles

Self-Assembly of Cellulose Nanocrystals and Organic Colored Pigments as Reinforcement Matrix of Lipstick for Enhancing SPF.

The vermilion of the human lip, covered by a skinny epithelium with little melanin, is quite susceptible to damage from ultraviolet (UV) radiation exposure. However, commercial sunscreen filters and indelible dyes used in lipsticks can cause health hazards after percutaneous absorption or accidentally oral administration. Inspired by plant pigmentation as natural filters to protect themselves against overexposure to UV, safer bio-based sunscreens of cellulose enveloped with anthocyanin (AN) were developed using bionic design. Cellulose nanocrystals (CNC), derived from acid hydrolysis of cellulose, reinforced enhancement of UV absorption and shielding properties of AN. This innovation addresses the issue that naturally sourced UV filter application to sunscreen does not achieve a desired sun protection factor (SPF) value because of the low specific extinction value (E1,1). We also stated that the diverse formula of anthocyanin sunscreen lipsticks with CNC exhibited 10 times more SPF value than AN alone. Furthermore, they possess competitive benefits such as pleasing texture, superior adhesion, impermeable, nonphototoxicity, ease of application, and removal. This work provides a promising proof-of-concept for studying the features of natural sunscreens in the design of simple, safe, efficient, and green sunscreens.

Scale-up issues for commercial depth filters in bioprocessing.

Significant increases in cell density and product titer have led to renewed interest in the application of depth filtration for initial clarification of cell culture fluid in antibody production. The performance of these depth filters will depend on the local pressure and velocity distribution within the filter capsule, but these are very difficult to probe experimentally, leading to challenges in both process design and scale-up. We have used a combination of carefully designed experimental studies and computational fluid dynamics (CFD) to examine these issues in both lab-scale (SupracapTM 50) and pilot-scale (StaxTM ) depth filter modules, both employing dual-layer lenticular PDH4 media containing diatomaceous earth. The SupracapTM 50 showed a more rapid increase in transmembrane pressure and a more rapid DNA breakthrough during filtration of a Chinese Hamster Ovary cell culture fluid. These results were explained using CFD calculations which showed very different flow distributions within the modules. CFD predictions were further validated using measurements of the residence time distribution and dye binding in both the lab-scale and pilot-plant modules. These results provide important insights into the factors controlling the performance and scale-up of these commercially important depth filters as well as a framework that can be broadly applied to develop more effective depth filters and depth filtration processes.

Application of a novel nylon needle filter-based solid-phase extraction device to determination of 1-hydroxypyrene in urine.

In this work, a simple and miniaturized solid-phase extraction device was constructed by connecting a commercial nylon needle filter to a syringe, which was applied for extracting 1-hydroxypyrene from a urine sample via hydrophobic and hydrogen bond interactions. The nylon membrane in the needle filter acted as the solid-phase extraction adsorbent, meanwhile, it filtered the particles in the urine sample. To obtain high extraction efficiency, key parameters influencing extraction recovery were investigated. The entire pretreatment process was accomplished within 5min under the optimal conditions. By coupling high-performance liquid chromatography-ultraviolet, a rapid, low-cost, and convenient nylon needle filter-based method was established for the analysis of 1-hydroxypyrene in a complex urine matrix. Within the linearity range of 0.2-1000 μg/L, the method exhibited a satisfactory correlation coefficient (R=0.9999). The limit of detection was 0.06 μg/L, and the recoveries from urine sample spiked with three concentrations (5, 20, and 100 μg/L) ranged from 105.8% to 113.1% with the relative standard deviations less than 6.7% (intra-day, n=6) and 8.9% (inter-day, n=4). Finally, the proposed method was successfully applied for detecting 1-hydroxypyrene in urine samples from college students, smokers, gas station workers, and chip factory workers. The detected concentration in actual urine samples ranged from 0.46 to 5.26 μg/L. Taken together, this simple and cost-effective nylon needle filter-based solid-phase extraction device showed an excellent application potential for pretreating hydrophobic analytes from aqueous samples.

Experimental Investigations of the Resistance Performance of Commercial Cylinder Filters and Effect Factors under Humid Airflows

Experiments were performed to summarize the variations in the resistance of commercial cylinder filters applied in the air intake filtration systems of gas power plants under humid airflows. Seven clean cylinder filters composed of various materials (including synthetic, wood cellulose, nanofibers, and polyester fibers) are subjected to the airflow containing water mist. The results show that the resistance of polyester fiber filters and synthetic fiber filters was increased by the large droplets on the surface of the hydrophobic filter media when loaded with water droplets generated. Several factors including the water-holding capacity (WHC) of fibers, low filtration efficiency, and the unique composite structure of nanofiber filters media can limit the "Pjump" of cylinder filters, increasing the mass of water droplets loaded or avoiding the high resistance. By contrast, the resistance trends of nanofiber media increased significantly from the initial resistance when singly subjected to airflows with water mist at 5.96 g m-3 and 90% relative humidity, differing from the nanofiber filter whose resistance tends to stabilize. These differences were primarily caused by the pleat-free structures and the install directions of the nanofiber medium in the clamp, indicating differences in the filtration performance between the filter medium and its filters.

Living algae detection with a PDMS-liquid chlorophyll fluorescence microfluidic chip filter and a smartphone.

Building an optical filtration function into a microfluidic chip is a promising way of simplifying the optical detection system of a microfluidic device. In this paper, a PDMS microfluidic chip filter that is capable of transmitting chlorophyll fluorescence and blocking interfering light in the visible wavelength range was developed for living algae detection with a smartphone. The chip was fabricated by sealing a layer of crystal violet solution in a PDMS layer on the top of the Sudan II-doped PDMS slab, which has a straight microchannel. Optimum dye concentrations and thicknesses for the crystal violet solution layer and Sudan II-doped PDMS slab were investigated and determined by spectrum measurements. It was found that the cut-on range of this integrated microfluidic chip is extended to about 625 nm and the transmittance in the chlorophyll fluorescence range (650 nm to 710 nm) is as high as 95%, when 25 mg L-1 Sudan II-doped PDMS slab (with a 3 mm thickness) and 2 mg L-1 crystal violet solution (with a 0.3 mm thickness) were used. Living algae detection using this chlorophyll-fluorescence-filtering PDMS microfluidic chip and a smartphone-based imaging platform was achieved, and the results compared favorably with those using a commercial filter.

Evaluation of the Performance of Commercial Virus Filters in Biopharmaceutical Downstream Processes

Evaluation of the Performance of Commercial Virus Filters in Biopharmaceutical Downstream Processes

The control on adsorption kinetics and selectivity of formaldehyde in relation to different surface-modification approaches for microporous carbon bed systems

It is perceived that surface modification of microporous carbon is an efficient option to remove light-weight volatile organic compounds (VOCs) like formaldehyde (FA). To adjust textural characteristics with surface functionalities of amine/sulfur and amino-silane, the commercial activated carbon (AC) was treated with dicyandiamide/thiourea (AC-M) and N-[3-(trimethoxysilyl)propyl]ethylenedia (AC-S), respectively, by thermal/microwave-assisted solvothermal methods. The adsorption performance of honeycomb air filters packed with different bed heights of AC-M/-S adsorbents (e.g., 1.38 ± 0.05, 6.36 ± 0.06, 7.99 ± 0.04, and 10.93 ± 0.04 mm) was evaluated (relative to commercial AC-based filters) towards the adsorption removal of FA (10 Pa) in both single and binary mixtures with benzene (at 10 Pa). . Based on the partition coefficient and kinetic metrics, the AC-M/-S based filters showed higher efficacy for FA capture than commercial AC filter with increasing bed height (e.g., ≥ 7.99 ± 0.04 mm) to reflect the increased number of Lewis acid/base active sites on the bed surface. At the highest bed height (10.93±0.04 mm), AC-S was far superior with significantly enhanced selectivity of FA (by 20 times) over benzene with the accelerated mass transfer and acid-base surface interactions at the gas-solid interface. In contrast, AC-M outperformed commercial ACs for benzene adsorption from the binary gas mixture (breakthrough time (τ-value) of 683 min) with the aid of the improved surface porosity (71.8%) through the modification process. The kinematic data also confirmed that the adsorption affinity of modified AC-M/-S adsorbents was unaffected by the feed gas composition (single or binary phase) at the initial BT region. It thus supports the key role of surface modification technique on the enhanced adsorptivity of aldehyde and/or aromatic VOCs. This study is expected to help expand our basic knowledge on the interplay between surface/textural characteristics of modified AC and fixed-bed height to control the adsorptivity of air filter for efficient trapping of FA in either single or mixed phases with non-polar VOCs (like benzene).

Numerical Study of the Hydraulic Effects of Modifying the Outlet Pipe and Diffuser Plate in Pressurized Sand Filters with Wand-Type Underdrains

HighlightsAn outlet pipe with twice the cross-sectional area reduced the filter pressure drop by 12%.Two-outlet designs did not improve the hydraulic performance of the central wand.Flow uniformity in the sand bed was improved with a central downward outlet pipe.Abstract. The pressurized sand filters used in drip irrigation systems have three zones (the water inlet, sand bed, and water outlet) with different hydraulic behaviors. Previous studies that aimed to improve the hydraulic performance of these filters focused on the water inlet and sand bed by redesigning the diffuser plate and underdrain elements, respectively. In this study, we analyzed the consequences of modifying the water outlet of a commercial porous medium filter without changing its underdrain design. The original design consisted of a horizontal pipe connected to ten horizontal wands. Five additional designs that varied in size, orientation, and number of outlets were numerically studied in four operating modes (including two sand bed heights and two superficial velocities). Comparison with the commercial design indicated that (1) an outlet pipe with twice the cross-sectional area reduced the overall filter pressure drop by up to 12% and increased the flow uniformity within the sand bed; (2) two outlets led to symmetrical behavior for the amount of water drained per wand but did not improve the water volume drained by the central wand, which drained the least amount; and (3) a central vertical outlet of equal diameter as the commercial outlet produced a similar pressure drop but increased the flow uniformity within the porous medium. For completeness, two additional diffuser designs were also studied. In comparison with the original design, the proposed designs improved the flow uniformity and weakened the water vortex above the sand surface. Keywords: Computational fluid dynamics, Drip irrigation, Filtration, Granular bed, Modeling.

Influence of the synergy of neutron and gamma radiation and functional aging on the efficiency of a hybrid protection circuit

Due to the shortcomings of commercial filters and non-linear components for overvoltage protection in the conditions of synergy of neutron and gamma radiation and functional aging, the behavior of the hybrid protection circuit under the same conditions was examined. In order for the experimental procedure to correspond as closely as possible to the real situation, the load of the hybrid circuit was not adjusted by impedance. The standard model of the hybrid protection circuit recommended in accordance with IEC 1.3 is simulated using the software package PSPICE. To that end, it is necessary to create a varistor with appropriate elements. The equivalent inductance parameters were found to be stable in relation to the experimental conditions. It was also established that due to the synergy of neutron and gamma radiation and functional aging, there is a change in the steepness of the varistor characteristic and the tangent of the loss angle in the capacitors. The overall effect of neutron and gamma radiation and functional aging was tested on the hybrid circuit and on individual components. The experiments were performed under well-controlled laboratory conditions, and the combined measurement uncertainty of the experimental procedure did not exceed 5%.

Experimental testing of air filter efficiency against the SARS-CoV-2 virus: The role of droplet and airborne transmission

Verifying the capacity of different types of air filters to stop the propagation of the SARS-CoV-2 virus has become a strategic element to contain viral spreading in enclosed spaces. This paper shows the results of experimental tests about the capacity of different commercial filter grades to stop SARS-CoV-2 propagation using inactivated virions. In the first test, the obtained results showed that the F8 filter blocks SARS-CoV-2 propagation if it encounters a flow devoid of liquid phase, i.e., a biphasic flow that can wet the filtering material. On the contrary, as shown in the second test, the SARS-CoV-2 virus propagates through the F8 filter if the droplet content in the air flow is enough to wet it. In these operational conditions, i.e., when the filter is wet by a flow with a high droplet content, the absolute H14 filter was also shown to fail to stop the transmission of the SARS-CoV-2 virus. Lastly, in the third test, the viral load was shown to be stopped when the pathway of the infected droplet is blocked.

Fabrication of eco-friendly time indicator using cellulose-based materials

An eco-friendly time indicator (TI) was developed using cellulose-based materials. The TI comprises a dye, copy paper, nanofibrillated cellulose (NFC) film, and filter papers coated with NFC slurry and/or paraffin-free biowax. A suitable dye and its conditions were determined by observing the dye solutions and the migration pattern at the different concentrations. Commercial filter papers were prepared, and the dye migration rate, depending on physical properties, was evaluated. NFC was coated to control the dye migration rate of filter paper. In addition, biowax was used to impart hydrophobicity to filter papers used for supporting NFC films, storing the dye, and allowing the migration of dye. Finally, a TI was fabricated using those components. Methylene blue was selected as a dye for the TI due to its deep color and high solubility. The results showed that the key property of filter paper affecting the dye migration rate was the pore size. The migration rate could be reduced when NFC was coated on both sides of the filter paper. Since biowax modified the hydrophobicity of filter paper surface, it was used to make the NFC film-supporting paper, location for dye storage, and bottom-layer. In conclusion, a multilayered TI could be assembled using cellulose-based materials.

Performance Analysis of a Multi-Function Mach-Zehnder Interferometer Based Photonic Architecture on SOI Acting as a Frequency Shifter

A photonic frequency shifter based on generalized Mach-Zehnder interferometer (GMZI) architecture is presented and experimentally validated. The circuit consists of four Mach-Zehnder modulators (MZM) in a 4 × 4 network bounded by two 4 × 4 multimode interference couplers and functionally equivalent to two parallel dual-parallel MZM (DP-MZM). The circuit can offer static bias free operation, virtual connectivity control of the components, and spatial separation of up- and down-converted carriers, which can be collected from separate ports without using any optical demultiplexing filters. Thus, the design permits remote heterodyning (advantages which cannot be obtained using a commercial DP-MZM or filter based optical frequency shifter). Experimental investigation shows deviation from ideal performance due to possible fabrication error and poor fiber-chip coupling. A carrier suppression of >20 dB and spurious sideband suppression >12 dB relative to the principal harmonics is achieved without any tuning for bias adjustment. In addition to the frequency conversion, the integration feasible circuit can also perform as a sub-carrier generator, IQ modulator, and frequency multiplier.

Biochar Nanozyme from Silkworm Excrement for Scavenging Vapor-Phase Free Radicals in Cigarette Smoke.

Serious lung diseases and other health problems caused by tobacco consumption are becoming more and more prominent all over the world. Scavenging the excessive harmful free radicals in cigarette smoke is proven to be an effective method in reducing the above problems. Carbon-based nanozymes have been widely studied due to their ability of scavenging free radicals. Accordingly, the biochar derived from silkworm excrement was reported as a nanozyme with free radical scavenging ability. The biochar nanozyme calcination at 900 °C with better free radical scavenging abilities was loaded into commercial cigarette filters for the following free radical scavenging verification in tobacco smoke. Mouse model results reveal the lung tissue could be improved by the addition of biochar nanozyme. This work not only provides an effective approach to reduce the harm caused by tobacco but also provides potential applications to rationally realize low-cost, ease of production, and a wide variety of biochar sources.

Clarification of yeast cell suspensions by a highly porous polyamide nanofiber sponge

Depth filtration is an attractive method for initial clarification of broth for removing cells and cell debris. Electrospun nanofibers with their large specific surface area and a porous structure are known as attractive materials in filtration processes. However, dead-end filtration of cells through nanofiber mats (NFM) always leads to cake formation and increasing resistance. In this study, for the first time, a nanofiber sponge (NFS) or nanofiber aerogel was synthetized from polyamide 6 (PA6) building blocks. The NFS was flexible, highly porous and mechanically stable. The pore size of the NFS was tuned between 8 and 26 µm during the cryogenic processing step. Volumetric flux and filtration efficiency of the NFS depended on the pore size and the results were compared with those for NFM from the same PA6 nanofiber material. Dead-end filtration of Saccharomyces cerevisiae was feasible at a low differential pressure of 3.5 kPa and cell filtration efficiency was > 99 %. Modelling of the filtration process revealed that cake formation is prevented by NFS filters since cells are able to penetrate into the filter and to adsorb on their internal surface. The filtration characteristics were also compared with commercial depth filters and revealed the high flux of NFS filters along with the possibility to avoid filter aids and a low environmental impact. PA6-NFS filters may become a new and cost effective generation of filters for removing different cells or cell debris from broth and other applications.

Impact of music on the dynamic perception of coffee and evoked emotions evaluated by temporal dominance of sensations (TDS) and emotions (TDE)

The aim of the present work was to study the temporal effect of music on sensory perception and on the emotional changes while drinking coffee. Two different commercial filter coffees were evaluated by a group of 48 consumers using the Temporal Dominance of Sensations (TDS) method. The description was performed in silence and also while listening to two different musical fragments: one with a “sweet” connotation and the other with a “bitter” one. Under the same conditions (drinking coffee with and without musical stimuli), a different group of 72 consumers evaluated their perceived emotions (joy, fear, neutral, rejection, disgust, surprise, sadness and anger) by Temporal Dominance of Emotions (TDE). Data was analyzed by dominance curves and by ANOVA and MANOVA of the durations of dominance (for emotions and sensations). Coffee perception, in both cases, was modified by the musical stimuli. The duration of dominance of bitter was increased in the presence of “bitter” music, while it decreased with the “sweet” music. Moreover, the sweet attribute was practically not chosen for describing the coffee on its own, but its choice and duration as dominant increased while listening to the “sweet” musical fragment. Music had a larger impact on the perceived emotions. The “sweet” music was related to the emotion of joy, which was accompanied by surprise and also some sadness when drinking coffee (regardless of the type of coffee being drunk). The “bitter” music was linked to the emotions anger and fear. The effect of “sonic seasoning” and translation of emotions with a familiar product was observed.

Development of a Cellulose-Based Freshness Sensor (II) : Manufacture of Multilayer Freshness Sensor Using Cellulose-based Materials and Evaluation of Its Color Expression

Lately, the increase in consumers’ demand for food packaging safety standards to be followed has spurred a general interest in intelligent packaging technology that can monitor the status of the products in the packaging system. Commercialized sensors can indicate the freshness of food by expressing the colors based on the concentration levels of carbon dioxide (CO₂) in the food item. However, most of the freshness sensors are manufactured from synthetic polymer materials; therefore, it is necessary to develop an eco-friendly freshness sensor that uses biodegradable and recyclable cellulose-based materials.<BR>In this study, a multilayer freshness sensor was manufactured using cellulose-based materials such as commercial filter papers and cellulose nanofibers (CNFs) prepared in a laboratory. The filter paper with small pore size and large number of pores (No. 3) was selected by observing the color change of the immersed filter paper in a pH-sensitive dye, and used as a matrix expressing the specific color according to the CO₂ concentration. The top layer was prepared using enzyme-pretreated CNF (EN-CNF) to make a transparent film, and the middle and bottom layers were prepared using the biowax-coated filter papers with the lowest air permeability due to the largest pore size (No. 4). Finally, a eco-friendly freshness sensor was assembled using the matrix, CNF film, and biowax-coated filter papers, whose color expressions clearly differed based on their CO₂ concentration levels.

Use of Cellulose for the Production of Photocatalytic Films for Hydrogen Evolution Along the Lines of Paper Production

Following the example of photovoltaics, one approach to large‐scale photocatalytic hydrogen production is the irradiation of a correspondingly large catalyst area. Paper production is a process in which large areas can already be produced based on the main component: cellulose. Herein, the TiO2 photocatalyst modification PC500, which also uses platinum nanoparticles as a cocatalyst, is supported in two different ways using cellulose. On the one hand, the catalyst is fixed to the surface of a commercial filter paper and, on the other hand, a photocatalytic paper is produced. For comparison, the catalyst is immobilized by means of drop coating using Nafion and measured as a suspension. The cellulose‐stabilized films are active and hydrogen production is comparable with the activity obtained from the drop‐coating method. The experiments show that the aggregation behavior of cellulose can be used to produce photocatalytically active films. The preparation is easy and can be applied to different kinds of (photo)catalysts. Although the films are very active, their stability during reaction due to swelling and hydrogen production must be further improved.

3D PRINTING OF A LOWELL MAKES MASK IN PLA

Relevance: The new pandemic crisis caused by the Covid19 virus has led to a global shortage of personal protective equipment including FFP2 masks necessary for the exercise of professionals in direct contact with positive patients.&#x0D; Objective: 3D print a PLA mask similar to the FFP2 mask with the addition of an ULPA filter&#x0D; Methods. The designed mask is based on the general morphology of the FFP2 standard. This is how we downloaded the prototype of the «LOWELL MAKES». We have adapted this prototype to our craniofacial dimensions on the «Meshmixer» software, to finally export the prototype in STL format to print it by fused deposition modeling (FDM) via the 3D printer «XYZ Junior 1.0» equipped with a PLA (polylactic acid) filament.&#x0D; Results. The total duration of the printing of the full mask (the cover, the body of the mask, and the retentive filter grid) was around 4h30 min. Regarding the choice of the filter, we opted for two solutions, the first to cut an FFP2 mask and to use the parts obtained as being filters (doubled), the second being a commercial ULPA or HEPA filter. A ULPA (Ultra Low Penetration Air) filter can theoretically filter dust, pollen, and bacteria from the air with an efficiency of 99.999 % thanks to a size of 0.1 microns. Remember that the average size of the Covid-10 virus is around 0.1 µm and that the porosity of the FFP2 mask allows particles to be filtered with a diameter of around 0.6 µm at 94 %. In order to maximize the filtering effect while wearing this mask, we opted for the interposition of a ULPA filter covered by an FFP2 filter. We tested the tightness of this mask by checking for side leaks by maintaining a stabilized sheet on the outer cover by suction during inhalation. We have also added to the edges of the mask in contact with the face a peripheral silicone seal, polymerized on the face, to avoid any marks or scars after removal of this mask while increasing the comfort of the practitioner. The protocol that we chose by superimposing two filters (the first having a porosity of 0.6µm and the second of 0.1µm) allowed us to potentiate the filtration. This allowed the filter to be used for 40 hours. The total cost price of the mask is around 9 €.&#x0D; Conclusions. The «open source» community makes it possible to popularize 3D printing while making it easier for any 3D printer owner to appropriate their protective equipment at a reduced price, however, intellectual property remains a concern, in particular for medical parts that cannot be procured promptly during a pandemic crisis similar to that caused by the Covid-19 virus.

Feasibility study on the application of electrospun nanofiber webs for the air sampling of crystalline silica.

The aim of the present study was to first fabricate an electrospun PVC nanofiber web and then assess its applicability in sampling and measuring the concentration of airborne crystalline silica by comparing analysis results with a commercial PVC membrane filter under different ranges of airborne silica concentration. A filtration performance comparison was also made between an electrospun PVC web with nano-sized fibers and a commercial PVC membrane filter. Overall, the measured concentration of silica by the electrospun webs was 1.022 times higher than that of the commercial PVC filter in all studied ranges of silica concentration and the nanofiber media had higher filtration efficiency and lower pressure drop compared to the PVC membrane filter. This can be considered to be due to the lower fiber diameter and greater porosity (obtained from the 2D SEM image) of the electrospun nanofiber webs. This makes them suited for air pollutant sampling and determining its airborne concentration.

Smart fluorescent tag based on amine response for non-contact and visual monitoring of seafood freshness

The method of monitoring the freshness of seafood is not satisfactory for ensuring food safety. Here, we develop a filter membrane-based smart fluorescent tag with excellent biogenic amine response, which can monitor the freshness of seafood in real time and visually. We use green fluorescent fluorescein as an indicator and red fluorescent carbon quantum dots (RQDs) with aggregation-induced emission property as an internal reference. After simple mixing, they are deposited on the commercial filter membrane by physical deposition method to prepare the fluorescent tag. When amine molecules are present, the molecular conformation of fluorescein changes and the fluorescence increases rapidly, while RQDs have no obvious response, thus achieving a clear fluorescence color response to biogenic amines. Under UV light of 254 nm and 365 nm, the fluorescent tag showed sensitive, rapid, and color-responsive to ammonia in a wide range of 250–2.5 × 104 ppm. To further verify the practical application potential, the fluorescent tag was used to monitor the freshness of shrimp and crab in situ in real time, and satisfactory results were achieved. More importantly, owing to the reversible conformational change of fluorescein, the fluorescent tag can be reused and manufactured at low cost, making it a more attractive platform for freshness monitoring in the field of food safety.