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Paper, as a foldable, pollution-free, and low-cost material, has become a suitable support substrate for producing flexible thermoelectric (TE) generators to realize waste heat recycling and the application of human-powered electronic devices. We propose a facile fabrication method to modify cellulose paper with inorganic TE powders via vacuum filtration, making a modified paper that possesses good thermoelectric properties. By connecting the modified paper to copper foils, flexible paper-based TE generators (PTGs) are fabricated. The obtained PTG with three units of P–N modules can generate an output voltage of ∼41.2 mV at a temperature difference of 50 K. Based on this modified paper, a thermal sensor that responds to heat sources, such as fingers, is proposed with a rapid response time of 0.25 s. This work offers a promising strategy for the simple fabrication of PTGs, paving the way for achieving the commercial application of self-powered wearable electronics. [ABSTRACT FROM AUTHOR]

As acetonitrile is a widely used solvent for the chemical industry, the recovery of acetonitrile from acetonitrile wastewater is significant for both industrial cost reduction and environmental protection. In this article, a simple, low‐energy, and low‐cost strategy is proposed for the effective separation of acetonitrile from high‐concentration acetonitrile wastewater. The approach is based on a sequential combination of two steps: salt‐induced phase separation and hydrophobic filtration. The acetonitrile wastewater was first induced to split into two phases by salt, that is, the acetonitrile‐rich phase and the water‐rich phase, then the above two phases were poured into the hydrophobic filter paper funnel for the separation. It was shown that NaCl is a suitable salting‐out reagent, and that hydrophobic filter papers—obtained from modification by butyltrichlorosilane and octyltrichlorosilane were the optimal choice for hydrophobic filtration. The salt‐induced phase separation process is able to increase the volume fraction of acetonitrile in the acetonitrile‐rich phase up to 92%. The acetonitrile‐rich phase can pass through the hydrophobic filter paper, whereas the water‐rich phase was intercepted. The hydrophobic filter paper retained strong hydrophobicity and high acetonitrile‐separating capacity after 3 months storage, or upon immersion in acetonitrile‐water mixtures for 12 h, or applied for 25 consecutive separations. [ABSTRACT FROM AUTHOR]

Organic/inorganic thermoelectric hybrids demonstrate great potential for wearable applications. However, their scalability is hindered by an inferior power factor (S 2 σ). Nowadays, achieving deep optimization of S 2 σ necessitates a strategy to decouple the Seebeck coefficient (S) and electrical conductivity (σ). In this work, we propose a strategy to break the coupling between S and σ by constructing a Schottky interface that exhibits an energy-filtering effect. We validate the feasibility of this approach using a PANI/TiN–TiO2/carbon paper. The results demonstrate a 1.16-fold increase in σ and a 1.08-fold increase in S in PANI/TiN–TiO2/carbon paper achieved through the construction of a Schottky-type TiN/TiO2 interface. The separation of hole/electron at the TiN/TiO2 interface serves as the scattering center for ionized impurity scattering and facilitates the transport pathway for charge carriers. These factors are crucial in determining the simultaneous optimization of S and σ , respectively. Additionally, the energy-filtering effect of the TiN/TiO2 interface plays a positive role in the ionized impurity scattering mechanism by selectively filtering out low-energy carriers. This further strengthens decoupling of the thermoelectric properties. The 14.9% PANI/11.2% TiN–14.5% TiO2/59.44% carbon paper displays the highest S 2 σ and achieves a high ZT value of 223.6 μVm−1 K−2 and 0.31 at 300 K, highlighting the advantages of PANI-based thermoelectric hybrids. This work provides valuable guidance for the design of thermoelectric hybrids incorporating multi-interface morphology. [ABSTRACT FROM AUTHOR]

In recent years, the paper-based microfluidics has been gaining attention because it is regarded as an inexpensive tool for detection and analysis in biomedical applications and clinical settings. This report, for the first time, describes a relatively simple and fast method, i.e. filtration-assisted screen printing (FASP) that can produce microfluidic paper-based analytical devices (μPAD) at ambient condition with time for constructing the channel wall of fluidic channel as less as 30 s. The channel walls are constructed by the polymer retained inside the filter paper at the designated locations through filtration. It is found that the flow behavior inside the channels was affected by the channel width while the influence of filtration time on the channel dimensions and porosity is minimal. Detection of glucose was demonstrated using the μPAD as fabricated. The proposed method provides a fast and reliable alternative to other state-of-the-art fabrication techniques, which can facilitate in extending the research and development in paper-based microfluidics. [ABSTRACT FROM AUTHOR]

Air quality control has become increasingly important in many industrial areas. Glass fiber filter paper is widely used for the collection of airborne particulate matter. Since glass fiber is fragile, fiber dispersion is believed to be important for controlling filter paper properties. In this paper, the impact of fiber dispersion on filtration performance and tensile properties was studied. Two types of glass fiber filter paper prepared from six different dispersing methods were used to analyze the impact of dispersion on filtration and tensile properties. Rotational viscosity was used to characterize the fiber dispersion process. Dispersing strength and time had no significant effect on filtration properties, namely the pressure drop, penetration and figure of merit. The fiber composition should be the determining factor of filtration properties. Dispersing strength and time had little effect on the virgin tensile strength of glass fiber paper, while the tensile strength retention after folding was highly affected by dispersion. It is suggested that fiber cutting should be reduced in the fiber dispersion process for higher tensile strength retention. [ABSTRACT FROM AUTHOR]

The clogging or jamming of particle suspensions is a ubiquitous problem, hindering the efficiency of particle–liquid and particle–particle separations. Motivated by pressure screening in the pulp and paper industry, we characterize jamming of dilute and semi-dilute mono-disperse rigid-rod suspensions passing through channels mimicking dead-end and cross-flow filtration membranes, experimentally, using particle-tracking velocimetry. We observe that jams nucleate by either bridging of isolated particles across the constriction, or by localized mechanical entanglement of the particles, i.e., flocculation. Uniquely, we observe floc-formation during acceleration into the aperture and report this as primary mechanism for jamming events. We characterized the accumulation-release cycles of the jamming event using an exponential probability distribution; this distribution is indicative of a Poisson process. For jams nucleated by single-particle bridging, the distribution is (primarily) related to the number of fibers passing through the aperture; this is similar to dry, granular materials. For floc-based nucleation events, the distribution is (primarily) related to the suspension concentration with the average time between jams decreasing inversely with the square-root of the initial suspension concentration. For the conditions tested, the distribution was insensitive to changes in constriction geometry. [ABSTRACT FROM AUTHOR]

Advanced carbon materials are important for the next-generation of energy storage apparatus, such as electrochemical capacitors. Here, the physical and electrochemical properties of carbonised filter paper (FP) were investigated. FP is comprised of pure cellulose and is a standardised material. After carbonisation at temperatures ranging from 600 to 1700 °C, FP was contaminant-free, containing only carbon and some oxygenated species, and its primary fibre structure was retained (diameter ≈20-40 μm). The observed enhancement in conductivity of the carbonised FP was correlated with the carbonisation temperature. Electrochemical capacitance in the range of ≈1.8-117 F g−1 was achieved, with FP carbonised at 1500 °C showing the best performance. This high capacitance was stable with >87 % retained after 3000 charge-discharge cycles. These results show that carbonised FP, without the addition of composite materials, exhibits good supercapacitance performance, which competes well with existing electrodes made of carbon-based materials. Furthermore, given the lower cost and renewable source, cellulose-based materials are the more eco-friendly option for energy storage applications. [ABSTRACT FROM AUTHOR]

Nanofiber has shown outstanding performance in many studies. Blending nanofibers into fibrous filter media is a promising way to improve the filtration performance. This paper discussed the modeling method for multi-fiber filter paper and the proper way to apply nanofiber into filter paper. Sixteen different filter papers were prepared and these filter papers covered the range of coarse-fiber-dominant and fine-fiber-dominant fibrous structure. The theoretical modeling method in this study for pressure drop and penetration of multi-fiber filter paper showed accurate results compared with the experiment data. It was found that for the higher quality factor, the nanofibers should be effectively separated by the coarse fibers. This study presented the idea of the fiber's effective contribution to filtration efficiency, which can lead to a comprehensive and distinct understanding of fibrous structure and filtration properties. [ABSTRACT FROM AUTHOR]

The material most commonly used to filter and clean the intake air of vehicle internal combustion engines is pleated filter paper, which in most cases is shaped in the form of a cylinder or panel. The production technology has a low cost and is not complicated. In addition to high separation efficiency and filtration performance, pleated filter media are required to have low initial pressure drop, which depends on the geometry of the bed. Much research has been conducted in this area. Dust accumulated in the filter bed causes an increase in pressure drop, which is the cause of deformation and sticking of pleats. The lack of stability of the pleats, the need to strengthen them, and the need to obtain small sizes while achieving high efficiency and accuracy of filtration of engine intake air was the reason for the development of a different design and a new technology for making filter cartridges called PowerCore. The distinctive feature of these filters is axial flow in one direction of the air stream, which avoids turbulence and thus minimizes pressure drop. This paper presents a comparative analysis of a standard PowerCore and PowerCore G2 filter bed and two cylindrical filters with a pleated filter bed made of cellulose and polyester. The conditions and methodology of experimental testing of filters with test dust are presented. During the tests, the characteristics of separation efficiency and filtration performance, as well as pressure drop as a function of the mass of dust retained on the filter of two PowerCore filters and two cylindrical filters were performed. Three specimens of test filters with the same filtration area were made from each sample of filter bed. The results showed that in each test of the filter bed, there is an initial filtration period characterized by low (96–98%) initial separation efficiency and the presence of large (dpmax) dust grains. As the dust loading of the bed increases, the separation efficiency and filtration performance obtain higher and higher values. The initial period of filtration ends when the conventional value (99.9%) of separation efficiency is reached. The duration of this period depends on the type of filter bed and for the PowerCore G2 filter ends for a dust loading of km = 33.1 g/m2, and for the cellulose filter for km = 117.3 g/m2. During the initial period, the air behind the PowerCore G2 filter contains grains with sizes in the range of dpmax = 9–16 µm. Behind the cellulose filter, dust grains are much larger, dpmax = 17–35 µm. The total operating time of the PowerCore G2 filter, limited by the achievement of the permittivity resistance Δpwdop = 3 kPa, is twice that of the other filter compositions tested. [ABSTRACT FROM AUTHOR]

Highlights • Facile synthesis of nanoparticles using hydrothermal method. • Impregnation of nanoparticles in water-resistant cellulose foam paper. • Morphological, structural, and elemental characterization using SEM and EDX. • Antibacterial evaluation of impregnated paper against gram positive and gram negative bacteria. • Enhanced antibacterial profile of nanoparticle modified filter paper compared to unmodified paper. Abstract Filtration is a promising water treatment method to purify drinking water. To develop highly efficient drinking water filter paper, water-resistant cellulose foam paper with a high wet strength property was fabricated using diverse metal oxide (e.g., copper oxide (CuO), zinc oxide (ZnO), and silver oxide (Ag 2 O)) nanoparticles. These nanoparticles were synthesized using the hydrothermal reaction method. Their morphological structures were studied using a field emission scanning electron microscope (FESEM). The presence of coated nanoparticles on the cellulose foam filter was verified by energy dispersive X-ray spectroscopy (EDX) methods. The antibacterial performance of different types of modified cellulose foam filters was studied against E. coli, P. aeruginosa, B. subtilis, and B. cereus strains using the zone of inhibition test. The antibacterial profile of the cellulose foam filter impregnated with Ag 2 O nanoparticles, when tested against different types of bacteria, exhibited higher antibacterial activity than the cellulose foam filter impregnated with ZnO and CuO nanoparticles. [ABSTRACT FROM AUTHOR]

Highlights • For the first time, vacuum-filtration followed by high temperature carbonization process was used to fabricate carbon fiber paper based electrodes. • During the carbonization process, carbon fiber paper was activated and graphene oxide was highly reduced in one step simultaneous. Abstract In this paper, we report a facile and cost-effective approach to synthesis carbon fiber paper (CFP) based electrode coated with reduced graphene oxide (RGO) by vacuum filtration and carbonization. The SEM image showed that graphene was deposited on each individual carbon fiber and the hybrid electrode paper retained its three dimensional structure which provided efficient percolation path ways for electrons. The specific capacitance of the hybrid paper reached 1076 mF cm−2 at 5 mV s−1 according to cyclic voltammetry measurement. Further, the assembled symmetric supercapacitor delivered a high capacitance of 344 mF cm−2 at 0.5 mA cm−2. In a word, this feasible method should be appropriate for the fabrication of carbon fiber paper based electrodes. [ABSTRACT FROM AUTHOR]

Filter paper technique (FPT) is known to measure both matric and total suctions in a wide measurement range. However, it has many individual errors due to the uncertainty of calibration curve and sensitivity of the measurements to the temperature and relative humidity variations. Besides, the ASTM procedure for FPT does not specify any sample preparation and repetition for experiments. In this regard, this study covers the reliability of suction measurements using the FPT and its application on zeolite-bentonite mixtures (ZBMs), which were proposed for use of liner material in the literature. A calibration curve for Whatman No. 42 filter paper was constructed and compared to the other calibration curves given in the literature. Due to large scatter of calibration curves, total suction measurement is found to be inconvenient for suction values under 1000 kPa. An improvement in sample preparation and necessary minimum numbers of tests are also suggested. When preparing the test specimen, the compacted sample is recommended not to be cut but to be compacted separately as upper and lower parts where the contact filter paper to be placed in between in order to obtain good contact area to measure the matric suction accurately. The necessary minimum numbers of tests for ± 10% accuracy band in a confidence level of 95% for ASTM procedure on ZBMs are suggested. Repetitions were found to vary depending on the suction type and bentonite content. Repetitions of six and eight times are recommended for 10% ZBMs for matric and total suction measurements, respectively. Similarly, for 20% ZBMs the repetitions of six and ten times are found for matric and total suction measurements, respectively. In addition, the influence of index properties and compaction states on suction was also investigated. Matric suction values decrease from dry of optimum water content to the wet of optimum water content and approach to zero for higher water contents. The suction values are found to increase with decreasing water contents where the dry density and the void ratio were constant. On the other hand, for a given water content, matric suction values are found to be increasing with increasing dry densities, while the void ratio was decreasing being more evident at relatively higher saturation degrees. [ABSTRACT FROM AUTHOR]

The hemp root bast paper is innovatively prepared to research the oil filtration properties and air filtration properties for practical application. It can be found that beating degree and weight both have great influence on air permeability, pore diameter distribution, oil/air penetration and oil/air filtration efficiency of hemp paper. The oil filtration efficiency of hemp papers for 0.33 µm particles is 99.7%–99.975% and air filtration efficiency for 0.26 µm NaCl aerosol particles is 99.942%–100%. Through comparison of oil filtration properties and air filtration properties with commonly used automobile engine oil/air cotton paper filtration materials, it can be found that hemp paper has the smaller thickness, weight, mean pore diameter, porosity and oil/air penetration, while the better oil/air filtration efficiency and higher pressure drop. Due to the higher filtration efficiency of hemp papers and green, biodegradable, sustainable resources of hemp plants in the case of environmental requirements, the pilot trial hemp paper automobile engine oil filter is successfully manufactured. The results indicate that hemp papers have better oil/air filtration properties than cotton paper in practical application. We hope that such an attempt will be helpful for practical application of hemp paper and meet the needs of domestic market for filtration materials. Furthermore, it can enlarge the application field and increase the added value of hemp. [ABSTRACT FROM PUBLISHER]

The article presents information about measuring the amount of gingival fluid using a simple filter paper strip viewer. The most widely used method of collecting gingival exudate is inserting filter paper strips at different depths into the gingival crevice. A simple filter paper strip viewer which possesses the versatility of a microscope with eyepiece graticule can be easily constructed. It consists of a lens, a condenser, glass slides carrying strips of filter paper and a light source. Stained filter paper strips are placed between the glass slides that are sealed with an acrylate adhesive.

Abstract: Exfoliated graphite nanoplatelets (xGnP) were produced by acid intercalation followed by thermal exfoliation and a controlled size reduction to produce graphite nanoplatelets of 1–15μm in lateral dimension and approximately 10nm in thickness. These highly hydrophobic nanoparticles were dispersed and stabilized in a DI water/polyethyleneimine (PEI, a cationic polyelectrolyte) solution. A free standing, mechanically robust paper of xGnP was prepared by vacuum filtration. The effect of xGnP size, polyelectrolyte coating and paper porosity on thermal transport properties was investigated. It was found that the annealing process improves the thermal conductivity by decomposing the PEI molecule that is adsorbed on the xGnP particles while still maintaining the porosity of the paper. Mechanically compressing the sample effectively reduces the pore volumes within the paper and increases the contact area among individual platelet. The strong alignment effect and larger contact area was evidenced by a 80% increase in in-plane thermal conductivity (178±12W/mK) and a 10% reduction in through-plane conductivity (1.28±0.12W/mK). This flexible, lightweight, low-cost, paper material made of xGnP particles is a promising candidate for applications requiring 2D heat conduction. [Copyright &y& Elsevier]

The single-factor experiment was used to investigate the effect of filter wrap' s air permeability, tipping paper's air permeability, and perforation row number on the filter ventilation rate of the cigarette. Furthermore, the effects of three factors and their interaction on the filter ventilation rate of the cigarette and the chemical composition of mainstream smoke by split-plot experiment were analyzed. The results showed that the filter ventilation rate of the cigarette increased with the increase of tipping paper's air permeability or perforation row number in single-factor experiment and split-plot experiment. In the range of 3300 ~ 8000 CU, the effect of the permeability of the formed paper on the ventilation rate of the cigarette filter was significant. After exceeding 8000 CU, the effect of filter wrap's air permeability on the filter ventilation rate of the cigarette decreased. The three factors of filter wrap's air permeability, tipping paper's air permeability, and perforation row number had significant interactions, which could coordinately adjust the filter ventilation rate of cigarette. With the increase of the filter wrap's air permeability, tipping paper's air permeability, and perforation row number, the content of nicotine, tar and COin the mainstream smoke of cigarette decreased. According to actual needs, the filter wrap's air permeability was 8000 CU, tipping paper's air permeability was 250 CU, and perforation row number was 3, which could reduce the content of nicotine, tar and CO in the cigarette smoke, and reduce the loss of smoke aroma. [ABSTRACT FROM AUTHOR]

Graphene oxide (GO) paper is an attracting structural material because of its high stiffness and light-weight. In order to exploit the high strength and stiffness of individual GO nanosheet into GO paper, the fabrication process must be optimized. In this study we fabricated ultra-stiff and strong GO paper by directed-flow vacuum filtration and compared its mechanical properties under different loading conditions. We also explored the effect of cross-linking with borax, thermal annealing and sonication to further enhance mechanical properties. The stiffest GO paper reported here has a tensile modulus of 109.9 GPa and a flexural modulus of 45.7 GPa. We also found that the flexural modulus of GO paper is significantly lower than the tensile modulus because of interlayer shearing, micro-buckling and delamination during flexural deformation. The properties of GO papers therefore need to be carefully selected for mechanical structures where flexion is the major deformation. This study provides significant insights about improving mechanical properties of GO paper and selecting GO paper for different loading conditions. Image 1095 [ABSTRACT FROM AUTHOR]

This comment jointly addresses experimental observations related to the functioning of coalescence filters with or without added drainage layer and their interpretation, put forth in the following papers by Chang, C., Ji, Z. and Liu, J.:. The effect of a drainage layer on filtration performance of coalescing filters. Separation and Purification Technology 170, 370-376, 2016 The effect of a drainage layer on the saturation of coalescing filters in the filtration process. Chemical Engineering Science 160, 354-361, 2017 Pressure drop and saturation of non-wettable coalescing filters at different loading rates. AIChE Journal 64, 180-185, 2018 The effect of a drainage layer on saturation and liquid distribution of oleophobic coalescence filters. Separation and Purification Technology 194, 355-361, 2018 These papers concluded that the addition of a drainage layer alters the behavior of a coalescence filter in terms of pressure drop evolution, saturation profile, as well as internal oil distribution pattern, in ways that necessitates significant modifications to the "Film-and-Channel-Model". Notably, the jump-Δp is supposed to be reduced in presence of a drainage layer. We were able to reproduce most of these experimental observations and find that the observed phenomena (especially those related to the shape of the Δp curve during loading) can be explained within the realm of capillary effects in fibrous media and without recourse to modifications of the Film-and-Channel-Model. Certain other data (e.g. those related to unusual oil distribution patterns) appear to have been impacted by experimental artifacts. We also show in this context that the mechanical compression of non-wettable coalescence media can lead to significant changes in apparent wettability. [ABSTRACT FROM AUTHOR]

Neural interfaces, such as microarrays and probes, consist of many electrodes for stimulating and recording purposes simultaneously. The multi-functional neural interface can suffer from many types of artefacts and noise, such as long-term use, environment, surrounding instruments and living subjects. This paper proposes a filtering approach by enhancing the band-pass and band-stop selection of the Kaiser Window finite-impulse response (FIR) filter based on the occurrence histogram of spectrum bands of neuronal signals in all channels. The implementation of the approach shows a clear enhancement of electrocorticogram (ECoG) signals by keeping the most important features and components, such as the interictal spikes. [ABSTRACT FROM AUTHOR]

Cost-effective, simple and flexible hydrogen gas sensors operating at room temperature were demonstrated based on DC magnetron sputtered palladium thin films. The main idea is to use commercial microfiber filtration paper as a cheap, fibrous and flexible substrate for palladium. With this objective, Pd thin films with 21, 38 and 54 nm thicknesses were deposited and characterized by grazing incident X-ray diffraction (GIXRD) and scanning electron microscope (SEM). The gas sensing behavior was tested by hydrogen gas in the concentration rang of 0.5–10%. GIXRD showed a PdX/Pd phase and SEM revealed existing of many structural nanocracks. An activation process was needed where sensors were heated up to 110 °C in the presence of 10% H 2. Then a desirable hydrogen sensitivity with good stability based on hydrogen induced lattice expansion (HILE) effect in which conductance increases was observed. However, for low Pd thicknesses (21 and 38 nm) and at below 4% H 2 , an inverse effect was observed in which the conductance decreased instead of increasing. For all samples the response time is incremental in the range of 0.5–4% and declining for 4–10%. Moreover, the deposited Pd sensors operate well when they are bent inward or outward. The governed physical mechanism was expressed and discussed. • Pd thin films were deposited on microfiber filtration paper by DC sputtering method. • Their hydrogen sensing properties were examined for different Pd thicknesses. • Sensing mechanisms including invers and direct current responses were observed. • The stability of sensing response of fabricated sensors was examined. • The response to bending in presence and absence of gas was investigated. [ABSTRACT FROM AUTHOR]

Highlights • Transparent paper was made from microfibrillated cellulose fibers by filtration. • It shows hierarchical structures of microsized fiber /nanosized fibril networks. • Its light transmittance is comparable to that of nanopaper made from CNFs. • It is formed within 2 min that is far shorter than the more than 3 h of nanopaper. • It shows higher thermal stability and larger tensile strength than the nanopaper. Abstract Fabricating transparent paper from cellulose nanofibers (CNFs) normally involves high energy or the use of expensive chemicals for the extraction of CNFs from cellulose fibers and time-consuming paper formation processes because of the slow filtration rate of CNFs. In this study, we reported a strategy for the fabrication of transparent paper using microfibrillated cellulose fibers (MFCFs), which were prepared by extracting nanosized fibrils from the cellulose fiber surfaces by a two-step refining process. The paper made from MFCFs has hierarchical structures of microsized fiber/nanosized fibril networks, where the microsized fiber skeletons are buried in the nanosized fibril networks. Consequently, the paper shows a light transmittance of 82.4% at 550 nm; this is comparable to the light transmittance (89.1%) of papers made from CNFs. Meanwhile, the filtration time of the paper made from MFCFs is less than 2 min, which is much shorter than the time (longer than 180 min) required for the formation of nanopaper made from commercial CNFs. In addition, the transparent paper made from MFCFs shows higher thermal stability, higher tensile strength, higher resistance to deformation, and more flexibility than the nanopaper made from commercial CNFs. This work provides a promising method for the manufacture of transparent paper from cellulose fibers. [ABSTRACT FROM AUTHOR]

The results achieved on industrial effluents from four different paper mills, ranging from highly diluted effluents from units for the production of fine papers using bleached cellulose, to much more concentrated effluents from an integrated pulp and paper plant, show the potential and advantages of the Biofor process. Implemented as a complement to or replacement for activated sludge systems, the Biofor® process, which dispenses with the clarification step and offers excellent resistance to sudden load and flow rate variations, is particularly well suited to the needs of this industry. This explains the rapid success already achieved in Europe and expected soon in North America. [ABSTRACT FROM AUTHOR]

We report a simple paper filter-based cross flow filtration method for air purification. We have examined a monolith filter array with a cross flow ratio of 1.0 and parallel and staggered filter arrays with a cross flow ratio of about 0.7 in terms of pressure drop and collection efficiency. The monolith filter array shows a monotonic increase in pressure drop from approximately 0.9 to 2.1 kPa. The parallel and staggered filter arrays reduce the increase in pressure drop, which can be maintained as low as 0.8 kPa over the entire range of dust loadings examined. The monolith filter array shows the highest collection efficiency, which is more than 95% over the entire range of dust loadings examined. The collection efficiency of the parallel and staggered filter arrays is initially as high as 70% and decreases to 30% when the dust loading increases to 40 and 100 g m−2, respectively. In particular, collected particles are more uniformly distributed on the staggered filter array than on the parallel filter array, resulting in the initial collection efficiency of 70% being sustained for a longer time. This uniform distribution in the staggered filter array may prevent a rapid increase in local pressure drop. This study provides insight into the development of filtration systems using simple paper filters without increasing the pressure drop and decreasing the collection efficiency. Copyright © 2022 American Association for Aerosol Research [ABSTRACT FROM AUTHOR]

In this study, the feasibility of Quantum dots (QDs) 2D distribution mapping on the substrate by Laser-Induced Breakdown Spectroscopy (LIBS) was examined. The major objective of this study was to describe phenomena occurring after applying aqueous solutions of QDs onto filtration paper. Especially, the influence of pH and presence of Cu 2 + cations in QDs solutions on LIBS signal was investigated. Cadmium Telluride QDs (CdTe QDs) were prepared by formation of nanosized semiconductor particles in so called “one-pot” synthesis. CdTe QDs were capped by glutathione or by 3-mercaptopropionic acid. The technique described in this work allows detection of QDs injected on the selected substrate – filtration paper. Results obtained from LIBS experiments were collated with a comparative method, fluorescence microscopy, which showed variations in the distribution of QDs on the substrate surface and possibilities for quenching. Due to the immediate signal response, relatively simple instrumentation and automatization possibility, LIBS offers promising and fast alternative to other techniques, as it is able to detect also nanoparticles with no visible luminescence. [ABSTRACT FROM AUTHOR]

Analytical filter papers are generally made of fibrous cellulose which has the potential to adsorb metal ions. In this study, blue band ashless filter paper was used to demonstrate one of the sources of error in the determination of the concentration of Fe2+, Co2+, Mn2+, Cd2+, Cu2+, Pb2+ and Zn2+ ions. For this purpose, the metal ion content of standard solutions in the 1-100 mg/l concentration range was analysed via FAAS before and after the filtration process. The corresponding results and the calculated percentage errors due to adsorption are presented. The effect of pH on the adsorption process was also investigated. Activated carbon and soil samples were spiked with each metal ion and the solid phases from the resulting solutions were separated by both filter paper methods and centrifugation. In the statistical estimation of the results, the paired t-test was applied for non-filtered and filtered solutions in the concentration range 1-100 mg/l using the data analysis tools available in MS Excel®. The use of filter paper caused systematic errors, particularly at lower metal concentrations, and hence centrifugation or a filtering process using techniques other than filter paper is favoured as a better approach towards estimating the concentration of heavy metal ions from aqueous solution. [ABSTRACT FROM AUTHOR]

Enzootic bovine leucosis (EBL) is a neoplastic disease of cattle caused by Bovine leukaemia virus (BLV). EBL causes great economic losses, so a fast and reliable diagnostic method is critical for understanding the status of BLV. This will allow us to control BLV infections efficiently and mitigate economic losses. In this study, we established a direct diagnostic test for BLV using dried blood‐spotted filter papers without sample pre‐treatment. The study was based on 159 clinical blood specimens collected in EDTA from one farm in Kyushu, Japan. The blood‐spotted filter papers were used as the template for direct filter PCR. When an ELISA was used as the diagnostic gold standard, the sensitivity and specificity of the direct filter PCR were 90.1% and 97.5%, respectively. The kappa value for the direct filter PCR and real‐time PCR methods was 0.97. The dried blood samples spotted onto filter papers were stable for at least 10 days at room temperature, even when the samples were from cattle with a low BLV proviral load. Direct filter PCR is a rapid, easy, reliable and cost‐effective diagnostic test that directly detects the BLV proviral genome in clinical blood specimens without DNA extraction. Moreover, it simplifies the collection, transportation and storage procedures for clinical blood specimens. [ABSTRACT FROM AUTHOR]

There has an increasing demand on the fabrication of flexible, light-weight, robust, cost-effective, and eco-friendly freestanding paper-like materials in view of their promising applications in energy devices, sensors, actuators, and chemical filters. With the unique planar structure and outstanding properties, graphene has been recognized as the most promising building block for the development of freestanding paper-like materials for various specific applications. Here, we highlight recent progress of graphene-based freestanding paper-like materials for sensing applications. The fabrication methods for graphene-based freestanding paper-like materials are introduced completely. Three main characteristics of graphene-based freestanding paper-like materials, including mechanical performance, electrical conductivity, and biological property, are also present. The sensing applications of graphene-based freestanding paper-like materials such as electrochemical sensors, resistance sensors, and deformation sensors are discussed in details. [ABSTRACT FROM AUTHOR]

Volatile organic compounds (VOCs) are hazardous to the environment and human health. Thus, tremendous effort has gone into developing effective/efficient techniques for separation of VOCs from their aqueous mixtures. In this work, a simple and versatile strategy was proposed to fabricate a new material for hydrophobic VOC separations, in which a self-assembling hydrogel consisting of TEMPO-oxidized cellulose nanofibers (TOCNs) and cationic guar gum (CGG) was used. Specifically, TOCNs and CGG were deposited onto a filter paper via a layer-by-layer procedure, resulting in a TOCN/CGG hydrogel-coated filtering material, in which no crosslinking agent was used. The hydrogel is spontaneously formed by electrostatic interactions and hydrogen bonding. The as-prepared filtering material exhibits oil-repellence and underwater oleophobicity resulting from the formation of hydration layer on hydrogel, thus demonstrating good VOC separation performance. One-layer of TOCN/CGG hydrogel coating (dried mass of 0.032 g·m− 2) was proved to realize the VOC separation (separation efficiency of around 99 % and water flux of as high as 905.14 L·m− 2·h− 1). Further increase of the hydrogel layers has negligible influence on the separation efficiency although it decreases the water flux. This filtering material also exhibits good stability during recycling. Consequently, this TOCN/CGG self-assembling hydrogel-coated filtering material has great potential in VOCs-contaminated wastewater treatment. [ABSTRACT FROM AUTHOR]

Coffee brew presents sensory, stimulatory and antioxidant properties highly appreciated by consumers, despite being associated with an increase in the level of blood cholesterol due to the effects of the diterpenes, especially cafestol, present in the lipid fraction. Although it is believed that the paper filter retains the brew diterpenes, new studies have shown that sometimes coffee filtered through paper can also increase the blood cholesterol level, putting in doubt the efficiency of the paper filter in retaining the diterpenes. Thus the objective of the present study was to verify the distribution of cafestol between the paper filter, the spent coffee and the coffee brew itself, from two coffee samples containing high and low cafestol contents selected from 13 samples of different cultivars and from different locations. In addition, the effect of the roasting degree on the cafestol contents of the roasted coffee was evaluated and the relationship between particle size of the roasted coffee and the extraction of solids. The highest cafestol content was found in the lightly roasted coffee, and the coffee brew presented higher solids contents when the particle size of the coffee powder was below 500 μm. The results showed that of the initial cafestol concentration present in the roasted coffee, the paper filter retained 12.41%, the spent coffee 87.45% and the brew 0.15%. Thus, one can conclude that the greater part of the coffee cafestol is retained by the spent coffee, due to the low extraction of the lipid fraction by the hot water. [ABSTRACT FROM AUTHOR]

[Display omitted] • New discovery for adsorption behavior on to carbon nanotube based gas sensor. • Mechanism for the difference in adsorption between polar and non-polar molecules. • Fabrication of uniform multi-walled carbon nanotube paper. Herein, we prepared a multi-walled carbon nanotube (MWCNT) paper by filtration, and tested its gas-sensing ability toward polar and non-polar organic solvents by comparing the magnitude of the adsorption sensitivity, response time, and reproducibility. The adsorption of non-polar organic solvents showed multilayered behavior; we presume that a stable adsorption layer is prevented from being formed owing to the measurement temperature used being higher than the critical gas temperature. [ABSTRACT FROM AUTHOR]

India has the highest burden of Tuberculosis (TB) and multidrug-resistant TB (MDR-TB) worldwide. Innovative technology is the need of the hour to identify these cases that remain either undiagnosed or inadequately diagnosed due to the unavailability of appropriate tools at primary healthcare settings. We developed and evaluated 3 kits, namely ‘TB Detect’ (containing BioFM-Filter device), ‘TB Concentration and Transport’ (containing Trans-Filter device) and ‘TB DNA Extraction’ kits. These kits enable bio-safe equipment-free concentration of sputum on filters and improved fluorescence microscopy at primary healthcare centres, ambient temperature transport of dried inactivated sputum filters to central laboratories and molecular detection of drug resistance by PCR and DNA sequencing (Mol-DST). In a 2-site evaluation (n = 1190 sputum specimens) on presumptive TB patients, BioFM-Filter smear exhibited a significant increase in positivity of 7% and 4% over ZN smear and LED-FM smear (p<0.05), respectively and an increment in smear grade status (1+ or 2+ to 3+) of 16% over ZN smear and 20% over LED-FM smear. The sensitivity of Mol-DST in presumptive MDR-TB and XDR-TB cases (n = 148) was 90% for Rifampicin (95% confidence interval [CI], 78–96%), 84% for Isoniazid (95% CI, 72–92%), 83% for Fluoroquinolones (95% CI, 66–93%) and 75% for Aminoglycosides (95% CI, 35–97%), using phenotypic DST as the reference standard. Test specificity was 88–93% and concordance was ~89–92% (κ value 0.8–0.9). The patient-friendly kits described here address several of the existing challenges and are designed to provide ‘Universal Access’ to rapid TB diagnosis, including drug-resistant disease. Their utility was demonstrated by application to sputum at 2 sites in India. Our findings pave the way for larger studies in different point-of-care settings, including high-density urban areas and remote geographical locations. [ABSTRACT FROM AUTHOR]

Background: Toxoplasma gondii is a protozoan with a worldwide distribution, in warm-blood animals, including humans. Local conditions and environmental disturbances may influence transmission dynamics of a zoonotic agent. This study evaluates the epidemiology of T. gondii based on toxoplasmosis prevalence in two populations of cats living in distinct urbanization conditions in Rio de Janeiro, Brazil. Methods: Among 372 domestic cats sampled, 265 were from a public shelter located downtown Rio and 107 from a relatively preserved wild environment in a residential area. Sera and eluates from dried blood spots were tested for detection of IgG antibodies against T. gondii by modified agglutination test (MAT). Results: Antibodies to T. gondii were detected in 32/265 (12.08%) animals from the public shelter and in 4/107 (3.74%) cats from the residential area. Identical results were observed for sera and eluates. Conclusions: Filter paper provides a reliable accurate alternative storage option when conditions of sample collection and transportation in the field are unfavorable. The significantly lower prevalence in the residential area is discussed in terms of environmental, biological and behavioral features. [ABSTRACT FROM AUTHOR]

A flexible Bi 2 Se 3 /Graphene (BSG) composite paper has been prepared through a simple vacuum filtration method and a thermal reduction together. The BSG composite paper was directly used as anode electrode for lithium-ion batteries, without using any polymer binders or conduction additives. In contrast to the pure Bi 2 Se 3 , the BSG exhibits high reversible lithium ion storage capacities and superior cyclic capacity retention. It proposed that the superior lithium storage performances would be attributed to the special construction of the as-prepared BSG paper, in which the graphene can not only act as conductive network for electrodes, but also act as a frame to alleviate volume expansion or aggregation of Bi 2 Se 3 nanosheets during lithiation/delithiation. The as-prepared BSG paper shows a great potential as an anode materials for flexible Li-ion batteries. [ABSTRACT FROM AUTHOR]

The graphene paper fabricated through an electrochemical exfoliation and filtration process provides high quality and massive graphene sheets in an ink form synthesised using artificial graphite as starting material. The product is mainly composed of bilayer and few layer graphene. Their lateral size can be up to >10 μm, and the quality determined by Raman spectroscopy is better than reduced graphene oxide. The cross-plane and in-plane thermal conductivity of the graphene paper can reach 5·5 and 3300 W m−1 K−1 measured by the direct method and the thermoelectric method respectively. [ABSTRACT FROM AUTHOR]

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Abstract: Highly sensitive SERS substrates based on deposition of silver nanoparticles on commercially available filter paper were prepared in this work, and used to overcome problems found in analyses of aqueous samples. To prepare silver nanoparticle- (AgNP) doped filter substrates, a silver mirror reaction was used. The procedures for substrate preparation were systematically optimized. Pretreatment of filter paper, reaction time, temperature, and concentration of reagents for silver mirror reactions were studied. The morphologies of the resulting substrates were characterized by field-emission scanning electron microscopy (FE-SEM) and correlated with the SERS signals by probing with p-nitrothiophenol (pNTP). Filter papers with different pretreatments were found to have different sizes and distributions of AgNPs. The best performance was found when filter paper was pre-treated with ammonia solution before growth of AgNPs. Based on the SEM images, the resulting AgNPs had roughly spherical shape with a high degree of uniformity. The silver-coated filter paper substrates provide much higher SERS signals compared to glass substrates and the reproducibility was improved significantly. Based on statistical analyses, the relative standard deviations for substrate-to-substrate and spot-to-spot were both were less than 8% and the enhancement factors for the substrates were, in general, higher than 107. The SERS substrates were used to selectively detect tyrosine in aqueous solution. Results indicate that filter-based SERS substrates are highly suited to detection of tyrosine. Compared to glass-based SERS substrates, 50 times more SERS signal was observed in detection of tyrosine. The linear range can be up to 100μM with a detection limit of 625nM (SN−1 =3). [Copyright &y& Elsevier]

Background: Appropriate methodology for storage biological materials, extraction of DNA, and proper DNA preservation is vital for studies involving genetic analysis of insects, bacteria, and reservoir hosts as well as for molecular diagnostics of pathogens carried by vectors and reservoirs. Here we tried to evaluate the utility of a simple filter paper-based for storage of insects, bacteria, rodent, and human DNAs using PCR assays. Methods: Total body or haemolymph of individual mosquitoes, sand flies or cockroaches squashed or placed on the paper respectively. Extracted DNA of five different bacteria species as well as blood specimens of human and great gerbil Rhombomys opimus was pipetted directly onto filter paper. The papers were stored in room temperature up to 12 months during 2009 until 2011. At monthly intervals, PCR was conducted using a 1-mm disk from the DNA impregnated filter paper as target DNA. PCR amplification was performed against different target genes of the organisms including the ITS2-rDNA of mosquitoes, mtDNA-COI of the sand flies and cockroaches, 16SrRNA gene of the bacteria, and the mtDNA-CytB of the vertebrates. Results: Successful PCR amplification was observed for all of the specimens regardless of the loci, taxon, or time of storage. The PCR amplification were ranged from 462 to 1500 bp and worked well for the specified target gene/s. Time of storage did not affect the amplification up to one year. Conclusion: The filter paper method is a simple and economical way to store, to preserve, and to distribute DNA samples for PCR analysis. [ABSTRACT FROM AUTHOR]

Abstract: This thesis deals with SiC/Si honeycomb ceramics carrier, which was prepared by ordinary papers through series of techniques including sol–gel technology, processes of folding, pasting, bio-mimetic design, low-temperature carbonization, high-temperature reduction carbonization and Si-removing. The phase composition, microstructure and mechanical properties of this carrier were analysed by XRD, SEM, TEM, three-bending tests, and the results showed that after carbonizing the ceramic paper turned into amorphous carbon, and through silicon infiltrating in the vacuum environment, the phase was composed of β-SiC, Si, and C. The bending strength of SiC/Si honeycomb ceramics carrier is 200MPa. The more silicon removing time is, the porosity of porous SiC will be increased, while its strength and toughness will be decreased. [Copyright &y& Elsevier]

Abstract: Paper-based biosensors represent a disruptive technology by providing instantaneous and low-cost diagnostics for health and environmental applications. The lack of sensitivity can be an obstacle for this technology to compete with traditional analytical instrumentations. Aiming to improve the sensitivity of a paper-based colorimetric biosensor, we have applied colloids engineering in combination with filtration to lower the paper substrate backgrounds and optimize the immobilization of bio-molecules on paper. A model system consisting of an enzyme, alkaline phosphatase (ALP), and an inorganic colloid, calcium carbonate (CC), flocculated by a cationic dimethylamino-ethyl-methacrylate polyacrylamide (CPAM), demonstrated that the optimized CC flocs are best for enhancing the detecting sensitivity of ALP. The CC floc structure on paper was optimized by modulating its structure in suspension. Subsequently, the filtration process and the wicking ability of paper enabled to freeze the deposited CC structure inherited from the suspension. The incorporation of biomolecules into the CC before immobilizing on paper through filtration provided not only a better microenvironment, but also a higher surface density of immobilized biomolecules. The ALP detection limit of 117fmol per zone (5mm circle) in the current study was fifty times lower than that of the common soaking method for biomolecule immobilization. The minimum amount of biomolecules per unit substrate area required for detection was lowered by over an order of magnitude, compared with spotting methods (i.e. inkjet printing). The improvement was also demonstrated by the steepest slope of standard curve, the lowest background, and the highest activity of the bioactive paper probed with the diluted BCIP/NBT liquid substrates. [Copyright &y& Elsevier]

NMR spectroscopy of urine samples is able to diagnose many inborn errors of metabolism (IEM). However, urinary metabolites have a poor stability, requiring special care for routine analysis (storage of urine at −20 or −80 °C, fast transport). The aim of our study was to investigate the reliability of dried urine filter paper for urine storage and transport and to evaluate the ability of NMR to detect several IEM using this method. Urine samples from five healthy subjects were analyzed by 1H NMR following different storage conditions (−20 vs 4 °C vs dried on filter paper) and at different time points (24 h, 48 h, 96 h, and 7 days). Urine pattern of fresh urine was considered as a reference. We analyzed the conservation of some amino acids and organic acids using Bland and Altman plot with intraclass correlation coefficient determination. Then, we evaluated the use of filter paper to detect four different IEM (methylmalonic and isovaleric acidurias, ornithine transcarbamylase deficiency, and cystinuria). Analysis of urine samples from healthy subjects revealed a high stability of studied molecules (ICC > 0.8) even after 7 days of storage on filter paper. Moreover, an excellent preservation of metabolites specifically accumulated in IEM was observed when analysis of dried urine filter paper was compared to fresh urine (coefficient of variation < 15%). This preliminary study demonstrates that storage of dried urine on filter paper is reliable for 1H NMR spectroscopy analysis. Preservation of urine molecules over time using that method is convenient for routine clinical practice. [Figure not available: see fulltext.] [ABSTRACT FROM AUTHOR]

To confirm the detection by FTIR (Fourier Transform InfraRed spectroscopy) of Iron oxides on filter papers, Goethite (α-FeOOH) was prepared and impregnated on commercial paper filters. FTIR in Reflectance mode (ATR) was run to test whether Goethite was detected or not. This oxide was chosen because of its deep and unique peaks. Comparison with obtained standards for Goethite showed that FTIR in reflectance mode was able to identify the 790 and 890 cm-1 absorption bands characteristic of this Iron oxyhidroxide. [ABSTRACT FROM AUTHOR]

In the pulp and paper industry, the water use minimization is a constant target. One way to reduce water use is to recycle the effluent in a closed-cycle concept. In paper mills, the main source of liquid effluent is the so-called whitewater, which is the excess water, originated from pulp stock dewatering and other fibre contaminated water. This research studied the reuse of paper mill whitewater after membrane ultrafiltration (UF) in the paper machine and in the pulp bleach plant of an integrated mill. Contaminant removal and flux behaviour of the UF system wore evaluated. The treatment by ultrafiltration was technically feasible and the treated whitewater had good potential to be reused in some processes in the paper machine. The reuse of ultrafiltered whitewater in the bleaching plant was not recommended because of the high level of soluble calcium present in this stream. Therefore, a combined treatment of the whitewater using the principle of precipitation and uftrafiltratlon was proposed showing good results and enabling the use of the treated whitewater in the bleach plant. [ABSTRACT FROM AUTHOR]

Abstract: The wastewaters of an Italian paper mill (Lucart), employing recycled paper, news print and cardboard as raw materials, were purified with membrane technologies with the aim to reuse the purified water in a closed loop in the paper manufacturing process. The performances of membrane technologies such as microfiltration (MF), ultrafiltration (UF), nanofiltration (NF) and reverse osmosis (RO) were tested in pilot plants. In order to optimise the purification process, different membranes and modules were tested to increase membrane productivity and to assure a chemical purification suitable for water recycling. The best filtration performances were obtained with a ceramic MF membrane having a cut-off of 0.14 μm, which assured a stable productivity of 150–200 L/m2h. On the contrary, spiral-wound polymeric modules, both of MF and UF, showed low productivity and high fouling indexes. The MF permeate, having an SDI less than 2, was treated in RO with a spiral-wound module, with high NaCl rejection. The RO permeate, obtained at 20 bar, showed very a low content of salts of 15 mg/L, conductivity of 70 μS/cm, COD less than 30 ppm of O2 and TOC of about 1 ppm. The MF process with a tubular ceramic membrane, followed by a RO filtration step on the MF permeate, allowed the recovery and reuse of more than the 80% of the original wastewater. This process was patented by ENEA-Lucart, deposit number RM2003A000603. [Copyright &y& Elsevier]

Abstract: Background: The collection of dried blood spots (DBS) on Whatman 903 cards has facilitated for years the detection of HIV-1 in infants by DNA PCR as early as 4–6 weeks after birth in resource-limited settings (RLS), but alternate blood collection devices are proving to be necessary. Objectives: The qualitative detection of HIV-1 DNA by PCR from DBS prepared on three commercially available blood collection cards was evaluated at the Centers for Disease Control and Prevention (CDC) and in four laboratories in Africa. Study design: DBS were prepared on Ahlstrom grade 226, Munktell TFN and Whatman 903, and stored under a variety of conditions. DBS were stored at ambient temperature (RT), 37°C with high humidity, and −20°C for varying lengths of time. The presence of HIV-1 DNA was tested using Roche Amplicor HIV-1 DNA (v 1.5) weekly for 4 weeks and at weeks 8 and 12 (RT and 37°C), at weeks 4, 8, and 18 (−20°C) of storage. DBS specimens were also tested after international shipment at RT. In addition, after nearly 3 years storage at −20°C, DBS were also evaluated independently using the COBAS Ampliprep/TaqMan HIV-1 Qual and Abbott RealTime HIV-1 Qualitative tests. Results: HIV-1 DNA was detected equally well on the three blood collection cards regardless of storage conditions and PCR assay. Conclusions: Ahlstrom 226 and Munktell TFN papers were comparable to Whatman 903 for HIV-1 DNA detection and may be considered as optional blood collection devices in resource-limited countries. [Copyright &y& Elsevier]

A practical method for collecting, storing, and transporting liquid biological samples in a dry state for subsequent hormone metabolite analyses is presented. This method employs the use of ordinary filter paper strips that imbibe liquid samples. Samples taken up by the filter paper were allowed to dry and were retained at ambient conditions in capped vials for up to 5 years prior to analysis. Examples presented in the present report include urine samples from human and nonhuman primates as well as solubilized fecal samples from nonhuman primates. Hormone metabolite analysis of the paper-stored samples provided data that were comparable to the results obtained from analyses of the original liquid samples. One year of storage had no effect on hormone concentration. Five years of storage resulted in concentrations that were quantitatively less bat qualitatively similar to the concentrations obtained by direct analysis of the initial samples. These data demonstrate the versatility and reliability of paper as a matrix for biological samples that may provide a more convenient approach for collecting and transporting samples collected in the field. [ABSTRACT FROM AUTHOR]

Amphoteric polyacrylamide (AmPAM) is a linear water-soluble polymer that has been applied in papermaking as an agent for flocculation, retention, filtration, and dry-strength improvement. However, AmPAM with different ranges of molecular weight (MW) have different properties in these processes. In this study, a series of AmPAMs were constructed with an anionic monomer, itaconic acid (IA), a cationic monomer, methacryloxyethyl-trimethyl ammonium chloride (DMC), and a main backbone of acrylamide (AM). Four factors influencing free radical polymerization, i.e., reaction temperature, pH, initiator load, and the concentration of monomers, were systematically investigated via an orthogonal test to determine their effects on the MW of AmPAM. Spectroscopy and isoelectric point assays were used to characterize the structure of the produced AmPAM, and the MW was assessed by calculating the viscosity. The reaction temperature had the greatest influence on the MW of AmPAM, followed by the solution pH and the initiator load. To determine the dry strength of papersheets containing AmPAM, the breaking length of handsheets was assessed after adding 0.5% AmPAM (based on fiber) with different MWs. The maximum value, 4.05 km, was 15.0% higher than the control and was obtained using AmPAM with a MW of 330 kDa. [ABSTRACT FROM AUTHOR]

A kind of flexible carbon nanotubes (CNTs) paper was investigated. Cellulose fibers were used as matrix and CNTs were used as conductive additive. The CNT papers were made by suction filtration method. The size and conductivity of the CNT paper can be arbitrarily tailored. The CNT papers show good electrical conductivity, electrochemical and electromagnetic interference (EMI) shielding properties. The electrical conductivity and (EMI) shielding effectiveness (SE) of CNT papers were enhanced with an addition of CNTs in the paper. The electrical conductivity increased from 9.92 S m −1 to 216.3 S m −1 and SE improved from 15 dB to 45 dB with a loading of CNTs from 10 wt% to 71 wt%. The CNT papers also show excellent applications for lithium ion battery, supercapacitors and zinc-manganese batteries. The testing results show that the capacity of supercapacitor reached 46 F/g at a scan rate of 5 mV/s. The reversible discharge capacity reached 474.0 mAh/g with the paper as anode current collector of lithium ion battery. The discharge capacity of Zn–Mn battery increased 100% when CNT paper replaced the graphite collector as current collector. [ABSTRACT FROM AUTHOR]

Abstract: During paper forming on a single-wire paper machine, i.e. a Fourdrinier or a hybrid paper machine, the pulp suspension is dewatered on a moving wire mainly through vacuum assisted devices (suction boxes). The dewatering process is supposed to occur by dead-end filtration under constant pressure as long as the fiber mat (filter cake) remains fully saturated with water. A physical model was written based on the kinetics of deposition of a compressible fiber mat and a drainage model for the filtrate. After some mathematical arrangements, a model similar to Hermans and Bredée’s formulation was obtained. It states that, at a constant suction pressure, the amount of filtrate per unit surface area is proportional to the square root of suction time. Our approach also yields an equation that is similar to the empirical drainage model used in the paper industry, which links the drained flow rate to a power law of the suction pressure and of the dwell time. By identification of the values of the coefficients, it is then possible to analyze the compressibility of the fibrous mat. For purpose of validation, experimental investigations were performed on one slotted suction box of a Fourdrinier pilot paper machine. The suction pressure was varied from 0.5 to 3.0kPa and the dwell time was changed by successively increasing the number of slots from 1 to 6 slots. The flow rate of filtrate was measured in each case in order to determine the corresponding specific amount of filtrate. Result analysis confirmed that the specific volume of filtrate varies as the square root of the dwell time. In addition, we could calculate the basis weight of the mat deposited on the wire upstream of the suction box and on the suction box itself, the average specific filtration resistance which was 1010 mkg−1 for the studied case. The methodology developed in this study can be transposed to other dead-end filtration processes. [Copyright &y& Elsevier]

Demonstration of successful elimination of lymphatic filariasis (LF) in endemic countries requires sensitive diagnostics for accurate definitions of endpoints and future surveillance. There has been interest in complementing available diagnostics with antibody serology testing in children, since negative serology would correspond with cessation of LF transmission. The Filariasis CELISA detects antifilarial IgG4 and has favourable results with serum samples but field application requires an easier sampling method. Ninety-four paired plasma and filter paper samples were assayed with promising results. The filter paper method resultedin a sensitivity of 92% and a specificity of 77% when compared to the paired plasma. One hundred and one filter paper samples were assessed for storage effects. Following 10-month storage at -20°C there was a significant reduction in reactivity (P < .001). Overall the results indicated that filter paper sampling would be a favourable sensitive and specific alternative for blood collection in surveys. [ABSTRACT FROM AUTHOR]