Synthetic Filter Research Articles

Implementation of phenols recovered from olive mill wastewater as UV booster in cosmetics

The current study investigates the application of different concentrations of phenols (recovered from olive mill wastewater) as UV booster in cosmetics. The spectrums (220–400nm) of 0–15mg olive phenols/L combined with physical (30mg TiO2/L) and chemical (5mg Benzophenone-3, 5mg Uvinol A, 2mg Octocrylene, 1mg OMC and 0.5mg OC-PABA/L) sunscreen agents were obtained and the in vitro SPF of respective solutions were calculated. In both UVB and UVA regions, absorption of synthetic UV filters increased as a function of olive phenols concentration, whereas the relationship between SPF increase and olive phenols concentration was linear. The corresponding equations could be used to estimate the amount of added olive phenols in order to reach a desirable SPF value and partially replace the amount of synthetic filters in the final product. The entrapment of olive phenols in silica particles and/or liposomes prior their emulsification in cosmetics was also investigated and resulted in an increase of phenols' water resistance. The results of the current study reveal the potentiality of using olive mill wastewater as a source for the recovery of phenols and their application as UV booster in cosmetics.

Tower-Based Greenhouse Gas Measurement Network Design---The National Institute of Standards and Technology North East Corridor Testbed.

The North-East Corridor (NEC) Testbed project is the 3rd of three NIST (National Institute of Standards and Technology) greenhouse gas emissions testbeds designed to advance greenhouse gas measurements capabilities. A design approach for a dense observing network combined with atmospheric inversion methodologies is described. The Advanced Research Weather Research and Forecasting Model with the Stochastic Time-Inverted Lagrangian Transport model were used to derive the sensitivity of hypothetical observations to surface greenhouse gas emissions (footprints). Unlike other network design algorithms, an iterative selection algorithm, based on a k-means clustering method, was applied to minimize the similarities between the temporal response of each site and maximize sensitivity to the urban emissions contribution. Once a network was selected, a synthetic inversion Bayesian Kalman filter was used to evaluate observing system performance. We present the performances of various measurement network configurations consisting of differing numbers of towers and tower locations. Results show that an overly spatially compact network has decreased spatial coverage, as the spatial information added per site is then suboptimal as to cover the largest possible area, whilst networks dispersed too broadly lose capabilities of constraining flux uncertainties. In addition, we explore the possibility of using a very high density network of lower cost and performance sensors characterized by larger uncertainties and temporal drift. Analysis convergence is faster with a large number of observing locations, reducing the response time of the filter. Larger uncertainties in the observations implies lower values of uncertainty reduction. On the other hand, the drift is a bias in nature, which is added to the observations and, therefore, biasing the retrieved fluxes.

Results of an interlaboratory comparison of analytical methods for quantification of anhydrosugars and biosugars in atmospheric aerosol

An interlaboratory comparison was performed to evaluate the analytical methods for quantification of anhydrosugars – levoglucosan, mannosan, galactosan – and biosugars – arabitol, glucose and mannitol – in atmospheric aerosol. The performance of 10 laboratories in Italy currently involved in such analyses was investigated on twenty-six PM (particulate matter) ambient filters, three synthetic PM filters and three aqueous standard solutions.An acceptable interlaboratory variability was found, determined as the mean relative standard deviation (RSD%) of the results from the participating laboratories, with the mean RSD% values ranging from 25% to 46% and decreasing with increasing sugar concentration. The investigated methods show good accuracy, evaluated as the percentage error (ε%) related to mean values, since method biases ranged within ±20% for most of the analytes measured in the different laboratories.The detailed investigation (ANOVA analysis at p < 0.05) of the contribution of each laboratory to the total variability and the measurement accuracy shows that comparable results are generated by the different methods, despite the great diversity in terms of extraction conditions, chromatographic separation - more recent LC (liquid chromatography) and EC (exchange chromatography) methods compared to more widespread GC (gas chromatography) - and detection systems, namely PAD (pulsed amperometric detection) or mass spectrometry.

An investigation into the performance of a high-speed synthetic fiber filter employing different types of coagulants

An investigation into the performance of a high-speed synthetic fiber filter employing different types of coagulants

Development and Evaluation of Photoprotective O/W Emulsions Containing Hydroalcoholic Extract of Neoglaziovia variegata (Bromeliaceae).

Neoglaziovia variegata is a Bromeliaceae plant species widely found in Brazil with several pharmacological properties, including photoprotective activity. Although herbal-based active ingredients have been applied in cosmetic products, especially for skin treatment, its application in sunscreen formulations remains unexplored. The aim of this work is to evaluate the photoprotective effect of cosmetic formulations containing hydroalcoholic extract of N. variegata (Nv-HA). Initially, the phenolic and flavonoid total content of Nv-HA were determined. The photoprotective activity of Nv-HA was subsequently assessed using a spectrophotometric method. Nv-HA was incorporated in O/W emulsions in the presence or absence of synthetic filters and their photoprotective efficacy was evaluated by spectrophotometric SPF determination. Finally, the stability study of the formulations was performed through the freezing/defrosting method. Nv-HA showed significant phenolic and flavonoids content (61.66 ± 5.14 mg GAE/g and 90.27 ± 5.03 mg CE/g, resp.). Nv-HA showed SPF values of 5.43 ± 0.07 and 11.73 ± 0.04 for the concentrations of 0.5 and 1.0% (v/v), respectively. It was verified that Nv-HA potentiated the photoprotective effect of formulations containing only synthetic filters. Furthermore, the formulations have remained stable at the end of the preliminary stability study. According to the results, it was concluded that Nv-HA can be used as a chemical filter in cosmetic formulations.

합성섬유 충진 여과수로를 이용한 건설사업장의 흙탕물 처리 및 배수구 보호에 관한 실험적 연구

In order to cope with the new and strict government regulations for turbid water discharge from construction sites, this study tested whether synthetic fiber filters can replace conventional best management practices. The filter efficiency was about 10 to 60% with a varying filter depth of 5 to 15cm, presuming extreme storm flow conditions to be in the range of 800 to 1500m/day of filtration rates. Fiber filter acts exactly like a granular filter, i.e. the separation efficiency is directly and inversely proportional to filter depth and rate, respectively. Based on the operational data, we suggested the Log-Log design relationship, which can be used to determine the filter depth and area. Compared to the widely used gravel filter which treats the turbid water at the construction site, about 20% higher efficiency was obtained under similar operating conditions. Cleaning the filter through a simple hand-washing method at the time of break-through, achieved about 90% soil recovery.

Investigation of single-pass tangential flow filtration (SPTFF) as an inline concentration step for cell culture harvest

This work examined the use of single-pass tangential flow filtration (SPTFF) to concentrate cell culture harvest. Conventional tangential flow filtration (TFF) is routinely used in biotechnology and related industries to concentrate protein solutions and exchange them into the final formulation buffer. However, several pump passes and a recirculation skid are required to achieve the target concentration in conventional TFF. Thus, it is impractical to implement TFF for inline concentration of protein solutions during the manufacture of biologic products. New developments in the biotechnology industry have focused on using ultrafiltration in a single pump pass (also known as SPTFF) to concentrate protein solutions in a single pump pass as an inline concentration step. There is thus a potential utility for this technology to overcome manufacturing bottlenecks. While there is limited work in literature describing the use of SPTFF for concentration of in-process protein pools, no work has been reported on the use of SPTFF for concentration of cell culture harvest and the challenges faced in this situation. This work examines the utility of using a 30kDa ultrafiltration membrane in the SPTFF mode to concentrate cell culture harvest for six different biologic assets in order to determine its feasibility over a wide range of biologic cell culture harvest streams. Cell culture harvest provided unique challenges to SPTFF that were overcome using a synthetic adsorptive hybrid filter technology. In particular, the hydraulic conditions necessary to achieve a targeted concentration factor varied from lot-to-lot for the same molecule. This caused difficulty in implementing a given set of operating conditions for the same molecule because of process instability. To address these challenges, we used high capacity adsorptive filters that effectively reduced both particulates and soluble contaminants during primary recovery to improve the SPTFF performance. The adsorptive filter mainly removed process related impurities, specifically HCP and DNA that prematurely fouled the ultrafiltration membrane and changed the capacity of SPTFF. The adsorptive filter also eradicated cell-culture lot-to-lot performance variability with SPTFF by offering a relative standard deviation of <10%. The use of SPTFF by simultaneously coupling the clarification with the concentration was successfully demonstrated. This is the first work to report the use of SPTFF to concentrate cell culture harvest for six different biologic assets, overcoming challenges using adsorptive filtration, and demonstrate debottlenecking for manufacturing.

Integrated Synthetic Bandstop Filters for Blocker Rejection at RF and Microwave Frequency Bands

In this paper, active synthetic band-stop filter (BSF) for interference rejection at 2–4, 4–8, and 8–16 GHz are presented. In the designs, a sharp notch, typically less than −50 dB for the entire frequency bands, is synthesized by subtracting the bandpass filter output from the all-pass (AP) output. The proposed synthetic notch filters allow optimization of filter dynamic range (DR) in the AP amplifier and frequency selectivity in the BPF independently, breaking the tradeoff between selectivity and DR ingrained in passive filters. In addition, the notch attenuation can be controlled independently of the filter bandwidth and center frequency tuning, providing more operational flexibility in suppressing blocker under a dynamic interference environment. The notch filters are fabricated in a 0.13- $\mu \text{m}$ SiGe BiCMOS technology. The measured gain is 0–1 dB for all three filters. The 2–4 GHz notch filter shows a 12–13 dB noise figure (NF) and a $- 2\sim -1.5$ dBm input 1-dB compression point (IP $_{{-1\text {dB}}}$ ) in the passband while drawing 20–30 mA from a 3.3-V supply. For the 4–8-GHz design, the measurement shows a 8–10-dB NF and a −1–1 dBm IP $_{-1\text {dB}}$ in the passband at the expense of 20–27.6 mA from a 3.3 V supply. For the 8–16 GHz filter, the measured NF is 14–17 dB and the IP $_{-1\text {dB}}$ is 0–4 dBm with a 70–90 mW dc power dissipation. The die areas are $0.68 \times 0.72$ mm2, $0.63 \times 0.63$ mm2, and $0.62\times 0.57$ mm2 for the S-band, C-band, and X-/Ku-band filters, respectively.

Fully synthetic filter materials for engine air filtration

Fully synthetic filter materials for engine air filtration

Occurrence and distribution of synthetic musks and organic UV filters from riverine and coastal sediments in the Pearl River estuary of China

This study reports the occurrence and distribution of synthetic musks (SMs) and organic UV filters (UVFs) in sediment samples collected in 8 riverine runoffs from the Pearl River and Pearl River estuary (PRE). Here, 6 of the 8 target compounds were detected in all sediments with concentrations ranging from 0.35ngg−1 to 456ngg−1. Higher concentrations of SMs and UVFs were evident in the eastern outlets compared to the western suggesting greater input of these contaminants from the Pearl River Delta (PRD) region. All the compounds showed a decreasing trend toward the seaward side which confirming that riverine runoff was the most important source of SMs and UVFs to the coastal environment. Notably, high levels of SMs and UVFs were detected in two fishing harbors in the PRE area. In comparison to UVFs, the SM compounds exhibited a significant correlation with TOC content in the sediments.

Novel Utilization of Terminators in the Design of Biologically Adjustable Synthetic Filters.

Terminators, which signal the end of transcription processes, are typically placed behind the last coding sequence of an operon to prevent interference between transcript units in most biologically synthetic systems. Here, we seek to extend the usability of terminators in genetic system design by using terminators as regulatory genetic parts. Terminators with different impacts on their upstream and downstream genes are characterized in detail via dynamic modeling to predict the behavior of the overall genetic system. Some nonlinear effects of terminators observed in our terminator measurements potentially facilitate regulation of gene expression. Through dynamic modeling in silico, we find that such genetic systems may behave like genetic filters. In agreement with the simulations, we successfully implement genetic high-pass and bandpass filters in vivo, demonstrating the potential of using terminators as regulatory parts. The genetic bandpass filter in this work is implemented through the interdependence between genetic parts, in which the termination efficiency of a terminator varies with the strength of the upstream promoter. This design strategy for a bandpass filter requires fewer base pairs than the conventional strategy of concatenating high-pass and low-pass filters. Our results show that this novel utilization of terminators as regulatory parts may provide a new perspective for efficient design of genetic circuits. We believe that further exploration of the complicated dynamics of terminators is important in the development of synthetic biology.

Color filter design method for multi-channel spectral acquisition system

The spectral reconstruction precision of multi-channel spectral acquisition system based on the commercial digital camera is greatly dependent on the filters used to acquire the image. In order to obtain optimal filter pair, which has excellent spectral reconstruction performance and is applicable to all image scenes, a color filter design method based on the principal component analysis is proposed in this work. Firstly, a number of widely-used color filters are collected and their transmittances are measured and then written in matrix form. Secondly, the proposed method is adopted to extract the first two principal components of the matrix. The normalized principal components are the transmittances of the desired synthetic filters. To compare the spectral reconstruction performance of the synthetic filters with the other filter pair obtained by a common used method, two virtual spectral acquisition systems were constructed with two pairs of filters. The performance of each system was evaluated in terms of chromatic difference and spectral root mean square error. The results indicate that the synthetic filters obtained by the proposed method have a better performance than the common used methods. In addition, the performance of the synthetic filters is stable when the target image scenes change.

Assimilating a synthetic Kalman filter leaf area index series into the WOFOST model to improve regional winter wheat yield estimation

The scale mismatch between remote sensing observations and state variables simulated by crop growth models decreases the reliability of crop yield estimates. To overcome this problem, we implemented a two-step data-assimilation approach: first, we generated a time series of 30-m-resolution leaf area index (LAI) by combining Moderate Resolution Imaging Spectroradiometer (MODIS) data and three Landsat TM images with a Kalman filter algorithm (the synthetic KF LAI series); second, the time series were assimilated into the WOFOST crop growth model to generate an ensemble Kalman filter LAI time series (the EnKF-assimilated LAI series). The synthetic EnKF LAI series then drove the WOFOST model to simulate winter wheat yields at 1-km resolution for pixels with wheat fractions of at least 50%. The county-level aggregated yield estimates were compared with official statistical yields. The synthetic KF LAI time series produced a more realistic characterization of LAI phenological dynamics. Assimilation of the synthetic KF LAI series produced more accurate estimates of regional winter wheat yield (R2=0.43; root-mean-square error (RMSE)=439kgha−1) than three other approaches: WOFOST without assimilation (determination coefficient R2=0.14; RMSE=647kgha−1), assimilation of Landsat TM LAI (R2=0.37; RMSE=472kgha−1), and assimilation of S-G filtered MODIS LAI (R2=0.49; RMSE=1355kgha−1). Thus, assimilating the synthetic KF LAI series into the WOFOST model with the EnKF strategy provides a reliable and promising method for improving regional estimates of winter wheat yield.

Broadband Synthetic Transmission-Line N-Path Filter Design

A synthetic transmission-line N-path bandpass filter technique that lowers the in-band insertion loss and increases the out-of-band rejection of the traditional N-path filter is analyzed. The performance limitations of the traditional N-path filter in terms of in-band insertion loss and limited rejection are reviewed. Measurement results from 0.1 to 1.6 GHz of a single-ended, four-stage synthetic transmission-line N-path filter fabricated in a 65-nm CMOS technology that achieves less than 5-dB insertion loss across the tuning range, 30–50-dB out-of-band rejection, in-band third-order distortion input-referred intercept point (IIP3) of $+$ 29 dBm, and a $+$ 11-dBm input-referred 1-dB compression point $({\rm P}1{\rm dB}_{\rm Jam})$ out-of-band jammer tolerance are presented.

Study of the influence of synthetic filter media compressive behavior on its dust holding capacity

Abstract In depth filtration, a challenge is to obtain the highest dust holding capacity (DHC) reaching a critical pressure drop in order to improve the filter medium lifespan. Such property can be driven by the design of the fibrous structure. Indeed, various structural parameters and properties can influence the behavior of the fibrous filter medium and the evolution of its filtration properties during the clogging. These parameters are fiber properties, morphology and blend, medium structure such as multilayer architecture, thickness and pore distribution along with medium properties such as compressive behavior in the thickness direction and flexural rigidity. The focus of this work concerns the study of the relations between the DHC and the compressive properties of bilayer fibrous structures. A method for estimating the number of fiber-to-fiber contact points of a fibrous structure composed of three types of fibers is proposed. The results show the possibility to significantly increase the DHC performance by controlling the compressive behavior of the fibrous medium.

The suitability of natural and synthetic filter material for the removal of petroleum products from the aqueous media

Petroleum products that have leaked into the natural environment are very hazardous. They are particularly dangerous for aquatic ecosystems. The major part of oils is carried into natural water bodies together with the surface outwashes from urban areas. One of the most inexpensive and easiest methods of the removal of oil contaminants from runoff is filtering. The authors of this study examined several synthetic substances (Duck and Reo-dry), and several vegetal materials (shredded stems of reeds, bulrush and lesser bulrush) and compared their filtration characteristics with the characteristics of the synthetic substance Fibroil now widely used for filtration. The authors of this study feel that the materials tested are suitable for the petroleum removal filter medium. Industrialists submit specifications of their products that were recorded under ideal conditions, at a low filtration rate. The authors studied filter material of natural origin as well as synthetic ones by simulating actual conditions that originate during heavy rains, i.e. at high filtration rates. In some aspects, low-cost vegetal material for the surface treatment of runoff performed better than the synthetic filters.

Ionizer assisted air filtration for collection of submicron and ultrafine particles-evaluation of long-term performance and influencing factors.

Previous research has demonstrated that unipolar ionization can enhance the filter performance to collect airborne particles, aeroallergens, and airborne microorganisms, without affecting the filter pressure drop. However, there is a lack of research on the long-term system performance as well as the influence of environmental and operational parameters. In this paper, both field and laboratory tests were carried out to evaluate the long-term particle collection efficiency of a synthetic filter of class M6 with and without ionization. The effect of air velocity, temperature, relative humidity, and particle concentration were further investigated in laboratory tests. Results showed that ionization enhanced the filtration efficiency by 40%-units during most of the operation time. When the ionization system was managed by periodically switching the ionizer polarity, the filtration efficiency against PM0.3-0.5 was maintained above 50% during half a year. Furthermore, the pressure drop of the ionizer-assisted M6 filter was 25-30% lower than that of a filter of class F7. The evaluation of various influencing factors demonstrated that (1) air moisture reduced the increase of filtration efficiency; (2) higher upstream particle concentration and air velocity decreased the filtration efficiency; and (3) the air temperature had very limited effect on the filtration efficiency.

Systematic Biological Filter Design with a Desired I/O Filtering Response Based on Promoter-RBS Libraries.

In this study, robust biological filters with an external control to match a desired input/output (I/O) filtering response are engineered based on the well-characterized promoter-RBS libraries and a cascade gene circuit topology. In the field of synthetic biology, the biological filter system serves as a powerful detector or sensor to sense different molecular signals and produces a specific output response only if the concentration of the input molecular signal is higher or lower than a specified threshold. The proposed systematic design method of robust biological filters is summarized into three steps. Firstly, several well-characterized promoter-RBS libraries are established for biological filter design by identifying and collecting the quantitative and qualitative characteristics of their promoter-RBS components via nonlinear parameter estimation method. Then, the topology of synthetic biological filter is decomposed into three cascade gene regulatory modules, and an appropriate promoter-RBS library is selected for each module to achieve the desired I/O specification of a biological filter. Finally, based on the proposed systematic method, a robust externally tunable biological filter is engineered by searching the promoter-RBS component libraries and a control inducer concentration library to achieve the optimal reference match for the specified I/O filtering response.

Life cycle assessment of spider silk nonwoven meshes in an air filtration device

Spider silk is a highly interesting protein fiber with outstanding properties. Since natural spider silk is not available for technical applications due to spiders’ cannibalism, the production of recombinant spider silk proteins has been established. The goal of this study was to examine the ecological impact of spider silk nonwoven layers in an air filtration device using comparative life cycle assessment. The investigation focused on the environmental benefits of using recombinantly produced spider silk proteins processed into nonwoven meshes in comparison to melt-blown synthetic polymer filter layers in dust bags. The considered functional unit was one dust bag containing spider silk in comparison to one commercially available dust bag. In case of spider silk dust bags, 9 kg of CO2-equivalents could be saved per domestic home and year in the category of global warming potential in comparison to commercially available ones. Assuming that all used dust bags would be furnished with spider silk nonwoven meshes, the overall benefit for exemplary Germany would be 241 million kg CO2-equivalents. This article contains supporting information that will be made available online once the issue is published.

Evaluation of Self Cleaning System in Aerosol Filtration Using Synthetic Filter

In industries that work with particulate material is observed from among other concerns, not to discard solid material in the air. Aiming to develop gas-solid filtration equipment more efficient, the study of a self-cleaning system utilizing filter fabric made ​​from synthetic material, was conducted using the phosphate rock as particulate material. The objective of this study is to evaluate the performance of a vibratory system filtration of gases. The system is made up a box filter coupled to an eccentric motor which causes a continuous vibration during the filtration cycle, not being necessary to interrupt the process to the procedure of fabric filter cleaning. We used polyester synthetic filter for the tests. With known relative humidity and temperature at which the tests were performed, it was possible to estimate the performance of the equipment in continuous vibration filtration of pulverulent material dispersed in gas currents, under the influence of different vibration frequencies.