9,751 results
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2. Preparation and pore forming mechanism of a NiCu alloy porous paper membrane
- Author
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Feng, Luli, Xu, Ziyi, Yu, Linping, Gao, Haiyan, Xie, Fengwei, He, Yuehui, and Shen, Weijun
- Published
- 2025
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3. Comment on "Cellular aggregation dictates universal spreading behaviour of a whole-blood drop on a paper strip".
- Author
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Li, Shuaijun
- Subjects
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ERYTHROCYTES , *POROUS materials , *FILTER paper , *CAPILLARIES , *PHYSICS - Abstract
Laha et al. studied the diffusive behavior of a whole-blood drop on filter paper using the generalized capillary bundle model. However, some model parameters should be further refined to accurately reflect the physics involved in this diffusion process. Moreover, citations are missing for some key equations. Addressing these aspects will improve the model applicability to this application and benefit readers in accessing more accurate and detailed information. [ABSTRACT FROM AUTHOR]
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- 2025
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4. Gel Cleaning in Heritage: Comparison of the Water Release among Gels and Traditional Pads.
- Author
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Sansonetti, Antonio, Riminesi, Cristiano, Mironiouk, Sónia, Proietti, Noemi, Di Tullio, Valeria, Nisticò, Roberto, Sacchi, Barbara, and Canevali, Carmen
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PAPER pulp ,POROUS materials ,WATER distribution ,STONE ,MEERSCHAUM - Abstract
Water release is a crucial aspect when considering cleaning effects on water-sensitive materials. In conservation practice, a water-based cleaning method which limits water release is very often needed. Unfortunately, this is not accompanied by an appropriate measure of the effectively released water. In this paper, water release has been measured by comparing traditional cleaning formulations, such as paper pulp and sepiolite, with several gar gel formulations, used by both Italian and European conservators. The assessment has been carried out by the gravimetric method, using three different stone material specimens as reference: Noto calcarenite, Manciano sandstone and Black Bergamo limestone, whose porosity values and distributions are known. Moreover, water distribution has been evaluated by portable NMR tests. Different commercial agar gel products (Bresciani, CTS, Sigma), having different concentrations (3, 4, and 5%), application modes (rigid at room T or fluid warm gels, with and without inserting Japanese tissue paper), and geometry (horizontal in gravity force direction or vertical), have been compared to obtain a full scenario among different water release mechanisms present in real conservation works. The paper faces the important issue of preparing reproducible chemical or water pads as well, useful for further research aimed at comparing cleaning effects in heritage conservation. The most interesting quantitative results can be summarized as follows. The water release measured from paper pulp and sepiolite was found to be 2 to 4 times higher than from any tested agar gel. Water release decreases by increasing agar concentration; an increase in the agar concentration by 1% induces a decrease in water release in the range 16.98–66.88 g depending on the stone; the increase from 4% to 5% is more obvious with respect to that from 3% to 4%. It is possible to assess the effect of the presence of Japanese paper, which is able to reduce the water release from 18 to 76%, depending on the stone and on the agar used. The gravimetric results were also used in the preliminary calibration tests of a contact probe named System Unit Salinity Index (SUSI), recently patented and useful in providing humidity and salinity indexes in a given porous material. [ABSTRACT FROM AUTHOR]
- Published
- 2024
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5. Application of Cellulose and Paper-Based Products in Building Acoustics.
- Author
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KLIMEK, Aleksandra, ŁĄTKA, Jerzy F., NIERADKA, Paweł, and DOBRUCKI, Andrzej
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PHYSICAL laws , *CONSTRUCTION materials , *ARCHITECTURAL acoustics , *GREENHOUSE gases , *POROUS materials , *SOUNDPROOFING , *THERMAL insulation - Abstract
This article explores the use of cellulose and paper-based products in building acoustics. It examines various materials such as cellulose wool, paperboard, corrugated cardboard, and honeycomb panels, and evaluates their acoustic absorption and insulation properties. The results indicate that these paper-based products can be effective alternatives to traditional materials in terms of both absorption and insulation performance. The article emphasizes the potential of paper-based materials in reducing the environmental impact of the building industry. The text also discusses the resonance frequencies and properties of Helmholtz resonators and double walls with the insertion of Helmholtz resonators, providing equations and formulas to calculate their resonance frequencies and transmission loss. It describes the measurement methods used to assess the sound absorption and sound reduction properties of various materials, including cellulose and paper-based products, and presents the results obtained from these measurements. The document also discusses the dynamic properties of paperboard and the testing methods used to measure these properties, as well as the results of tests conducted on cellulose wool. It highlights the environmental benefits of using recycled materials like cellulose wool. The text provides data and analysis on the acoustic properties of various cellulose and paper-based materials used in building construction, including cellulose wool, paperboard, corrugated cardboard, and honeycomb panels. The measurements include parameters such as sound reduction index, sound absorption coefficient, and dynamic Young's modulus. The results demonstrate that these materials have different acoustic characteristics and can be utilized for sound insulation and absorption in [Extracted from the article]
- Published
- 2024
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6. Deciphering the microstructural complexities of compacted carbon fiber paper through AI-enabled digital twin technology.
- Author
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Park, Young Je, Choi, Won Young, Choi, Hyunguk, Choi, Seo Won, Park, Jae-ll, Nam, Jieun, Lee, Jong Min, Myung, Kwang Shik, Yoon, Young Gi, and Jung, Chi-Young
- Subjects
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COMPUTED tomography , *POROUS materials , *CLEAN energy , *CARBON paper , *CARBON fibers - Abstract
In the decarbonized society based on the renewable sources, the carbon fiber papers (CFPs) are regarded as key porous materials for the electrochemical energy conversion and storage devices. Searching the optimum microstructure of assembled carbon fiber paper under compression is one of the central challenges in this uprising technology. Herein, we present a tomography-based analytical approach to correlate CFP microstructures and transport parameters under the compressed state. For the sake of artificial intelligence, the prediction accuracy on the pore and solid structures is dramatically improved up to 98 % consistency when compared with the analytical solution, by identifying the true shape of cylindrical carbon fibers. The three-dimensional U-net algorithm was incorporated into the conventional X-ray computed tomography, to gain a complete separation of carbon fiber and binder. Subsequently, the origin of two different microstructures in the through-plane direction, i.e. transitional surface region and core region, are investigated as a function of compression ratio (CR). Finally, the structure-property relationship of CFP is thoroughly evaluated over a wide range of the paper thicknesses, PTFE contents and CRs. We demonstrate that the microstructural three-dimensionality, which is one decisive factor determining the transport and electrochemical properties in energy devices, can be further analysed by exploring the formation factors of solid and pore structures with increasing CRs. The insights gained from this work not only enhance the fundamental understanding of CFP microstructures but also pave the way for optimizing the design and operation of next-generation energy devices, promising a more efficient and sustainable energy landscape. [Display omitted] • AI-based tomographic method is introduced for porous energy materials such as CFP. • Digital twins of compacted CFP distinguishing pore and solid structures is realized. • Origin of core/transition region is verified by varying thickness and PTFE contents. • Binder orientation affects in-plane gas permeability in CFPs under compression. • Formation factors converged to ε2–2.5 and ε3–4 under in-plane and through-plane directions. [ABSTRACT FROM AUTHOR]
- Published
- 2025
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7. 3-D Characterization of the Structure of Paper and Paperboard and Their Application to Optimize Drying and Water Removal Processes and End-Use Applications
- Published
- 2004
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8. Development and optimization of porous carbon papers suitable for gas diffusion electrodes. Final report, December 2000
- Author
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Fleming, Patrick
- Published
- 2001
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9. Characterizing the hydraulic properties of paper coating layer using FIB-SEM tomography and 3D pore-scale modeling.
- Author
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Aslannejad, H., Hassanizadeh, S.M., Raoof, A., de Winter, D.A.M, Tomozeiu, N., and van Genuchten, M.Th.
- Subjects
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PAPER coatings , *HYDRAULICS , *SCANNING electron microscopy , *POROUS materials , *PORE size distribution - Abstract
Paper used in the printing industry generally contains a relatively thin porous coating covering a thicker fibrous base layer. The three-dimensional pore structure of coatings has a major effect on fluid flow patterns inside the paper medium. Understanding and quantifying the flow properties of thin coating layers is hence crucial. Pore spaces within the coating have an average size of about 180 nm. We used scanning electron microscopy combined with focused ion beam (FIB-SEM) to visualize the nano-scale pore structure of the paper coating layer. Post-processing of the FIB-SEM images allowed us to reconstruct the three-dimensional pore space of the coating. The 3D FIB-SEM images were analyzed in detail to obtain pore size distribution and porosity value. The permeability was estimated using the GeoDict software, based on solutions of the Stokes equation. By determining the porosity and permeability of increasingly larger domain sizes, we estimated the size of a representative elementary volume (REV) for the coating layer to be 60 µm 3 , which is well within the volume analyzed using FIB-SEM. The estimated porosity and permeability of the REV domain were 0.34 and 0.09 mDarcy, respectively. Using the pore morphology method, capillary pressure-saturation ( P c - S ) and relative permeability curves of the REV domain could be constructed next. The P c -S curves showed that the coating had a high air entry suction, which is very favorable for printing in that ink will invade the coating as soon as it is applied to the coating. Our results are essential for macroscale modelling of ink penetration into a coating layer during inkjet printing. Macroscopic models can be valuable tools for optimization of the penetration depth and the spreading of ink on and within paper substrates. [ABSTRACT FROM AUTHOR]
- Published
- 2017
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10. The impact of sample size on transport properties of carbon-paper and carbon-cloth GDLs: Direct simulation using the lattice Boltzmann model.
- Author
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Gao, Yuan, Hou, Zhi, Wu, Xiaoyan, and Xu, Peng
- Subjects
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CARBON paper , *CARBON fibers , *SAMPLE size (Statistics) , *POROUS materials , *LATTICE Boltzmann methods , *PROTON exchange membrane fuel cells , *NUMERICAL analysis - Abstract
The transport properties of gas diffusion layer (GDL) in proton exchange membrane fuel cell are important parameters in fuel cell modelling, and one method to measure them is to simulate the transport of each species at spatial resolutions of a few microns in a microstructure of the GDL. One issue in this method is the size of the microstructure as using an unnecessarily big sample could substantially increase the computational cost. Both carbon-paper and carbon-cloth GDLs are investigated and their microstructures are obtained using numerical generation and X-ray micro-tomography respectively at a resolution of 1.733 µm. For each reconstructed GDL, we use the orthorhombic lattice Boltzmann model to simulate fluid flow through some subsamples taken from it in both the in-plane and the through-plane directions; the results show that the permeability of all subsamples is anisotropic in that their permeability in the in-plane direction is higher than in the through-plane direction. For each GDL, we compare its permeability calculated using samples of different sizes and find its representative elementary volume (REV) – a volume above which the calculated permeability represents the average ability of the GDL to conduct fluids. [ABSTRACT FROM AUTHOR]
- Published
- 2018
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11. Special Issue: "Feature Papers in Materials Simulation and Design".
- Author
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Bacciocchi, Michele and Milani, Abbas S.
- Subjects
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NATURAL fibers , *THERMAL conductivity , *MECHANICAL behavior of materials , *CARBON-based materials , *SLASH (Logging) , *JOB applications , *POROUS materials , *ASYMPTOTIC homogenization - Abstract
The title of the current Special Issue, "Feature Papers in Materials Simulation and Design", has identified the aims of this collection since its opening: the gathering of research works and comprehensive review papers that advance the understanding and prediction of material behavior at different scales, from atomistic to macroscopic, through innovative modeling and simulation. The paper by Chen et al. [[4]] aimed at studying the thermal properties and thermoelectric performance of imidazole-graphyne (ID-GY) by combining first principle calculations with the Boltzmann transport theory. The last paper by Cheng and Vescovini [[16]] presented instead an accurate and efficient numerical method for the analysis and design of Variable Stiffness (VS) laminates. Civalek et al. [[11]] developed an efficient eigenvalue algorithm for the axial vibration analysis of embedded short-fiber-reinforced micro-/nano-composite rods subjected to arbitrary boundary conditions. [Extracted from the article]
- Published
- 2023
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12. Amorphous B-Doped Ni/Crystalline Ni Porous Foil Derived from Chinese Rice Paper as High-Performance Bifunctional Electrocatalytic Electrode for Oxidation of Methanol and Urea.
- Author
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Hou, Guangya, Wu, Yitao, Chen, Qiang, Zhang, Jianli, and Tang, Yiping
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POROUS materials ,POROUS metals ,CHINESE painting ,ELECTROCHEMICAL apparatus ,DOPING agents (Chemistry) ,FOAM - Abstract
Constructing low-cost, high-catalytic-performance anode electrocatalysts is a significant challenge for methanol oxidation (MOR) and urea oxidation (UOR) reactions. Using paper templates with abundant pores to prepare thin porous metal materials helps to obtain high-performance electrode materials. The nano amorphous B-doped Ni/crystalline Ni (nanoam Ni-B/Ni) foil composite electrodes were derived from paper templates prepared by impregnation, high-temperature reduction, and electrodeposition methods. Porous Ni foils (Nip) derived thinnest rice ("Xuan") paper, initially used for Chinese calligraphy and painting, exhibits the best performance due to its strong adsorption and wettability. Compared to direct current electrodeposition, pulse electrodeposition yields finer amorphous B-doped Ni nanoparticles with good catalytic performance. Under a current density of 100 mA·cm
−2 , the nanoam Ni-B/Ni composite electrode prepared under a duty cycle of 0.5–1.0 s achieved current densities of 290.4 mA·cm−2 (MOR) and 340.4 mA·cm−2 (UOR) at 0.8 V, which are improved by 37.1% and 55.1%, respectively, compared to those of Nip. After 2000 cycles, with solution replacement, the current densities maintained 99.2% (MOR) and 81.6% (UOR) of the original values, showing excellent electrocatalytic stability. This research provided a new use for Chinese rice paper, and the prepared Nip-based electrode, with a thickness of about 60 μm and a low area quality, had a simple preparation process and good electrochemical properties, and can be used as a potential substitute for commercial Ni foam for portable or small electrochemical devices. [ABSTRACT FROM AUTHOR]- Published
- 2024
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13. Printed Capillary Microfluidic Devices and Their Application in Biosensing.
- Author
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Zhang, Zhiyi, Lang, Stephen, Pearson, Kate, Farhan, Yawar, Tao, Ye, and Xiao, Gaozhi
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MICROFLUIDIC devices ,POLYMER films ,CAPILLARIES ,DETECTION limit ,POROUS materials ,GLUCOSE - Abstract
Microfluidic devices with a free-standing structure were printed directly on polymer films using the functional materials that form interconnected pores. The printed devices can transport fluids by capillary action in the same fashion as paper-based microfluidic devices, and they can handle much smaller sample volumes than typical paper-based devices. Detection of glucose was performed using both colorimetric and electrochemical methods, and the observed limits of detection (LOD) were similar to those obtained with paper-based microfluidic devices under comparable testing conditions. It is demonstrated that printed microfluidic devices can be fabricated using printing processes that are suitable for high-volume and low-cost production and that the integration of microfluidic channels with electrodes is straightforward with printing. Several materials that are printable and form interconnected pores are presented. [ABSTRACT FROM AUTHOR]
- Published
- 2023
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14. Poly(vinylidene fluoride-hexafluoropropylene) polymer electrolyte for paper-based and flexible battery applications
- Published
- 2016
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15. Imbibition of Newtonian Fluids in Paper-like Materials with the Infinitesimal Control Volume Method.
- Author
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Song, Kui, Huang, Ruijie, and Hu, Xiaoling
- Subjects
MICROFLUIDIC devices ,POROUS materials ,FLUID control ,NEWTONIAN fluids ,CELLULOSE esters ,FILTER paper - Abstract
Paper-based microfluidic devices are widely used in point-of-care testing applications. Imbibition study of paper porous media is important for fluid controlling, and then significant to the applications of paper-based microfluidic devices. Here we propose an analytical approach based on the infinitesimal control volume method to study the imbibition of Newtonian fluids in commonly used paper-like materials. Three common paper shapes (rectangular paper strips, fan-shaped and circular paper sheets) are investigated with three modeling methods (corresponding to equivalent tiny pores with circle, square and regular triangle cross section respectively). A model is derived for liquid imbibition in rectangular paper strips, and the control equations for liquid imbibition in fan-shaped and circular paper sheets are also derived. The model is verified by imbibition experiments done using the mixed cellulose ester filter paper and pure water. The relation of imbibition distance and time is similar to that of the Lucas−Washburn (L−W) model. In addition, a new porosity measurement method based on the imbibition in circular paper sheets is proposed and verified. Finally, the flow rates are investigated. This study can provide guidance for the design of different shapes of paper, and for better applications of paper-based microfluidic devices. [ABSTRACT FROM AUTHOR]
- Published
- 2021
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- View/download PDF
16. Physics informed neural networks reveal valid models for reactive diffusion of volatiles through paper.
- Author
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Serebrennikova, Alexandra, Teubler, Raimund, Hoffellner, Lisa, Leitner, Erich, Hirn, Ulrich, and Zojer, Karin
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DIFFUSION , *PARTIAL differential equations , *CHEMICAL reactions , *POROUS materials , *PHYSICS , *VOLATILE organic compounds - Abstract
Predictive models for the transport of volatile organic compounds in paper need to consider the complex interplay of diffusion, adsorption, desorption, or chemical reactions. The relative importance of each of these processes is determined by the polarity of the volatile. Hence, it is challenging to pick a valid theoretical model that correctly predicts transport regardless of the polarity. Here, physics-informed neural networks (PINNs) assess which of five different models correctly describe transport of DMSO as polar and n-tetradecane as apolar model compound: (i) a pseudo first-order adsorption model for an irreversible sorption process, (ii) a first-order kinetics model allowing reversible sorption, (iii) a second-order model with a reversible process, and an effective diffusion model accounting for a constant (iv) and for a variable effective diffusivity (v). Each tested model is given as set of partial differential equations (PDE). Considering the model under testing and experimentally obtained spatially and temporally resolved concentration profiles through stacks of paper sheets, PINNs predict concentration of the volatiles and associated material constants such as sorption constants and effective diffusion coefficients by solving the inverse problem. Our PINNs revealed two models, pseudo first-order sorption and second-order reversible sorption, that correctly predict concentration profiles and polarity-driven differences in sorption times. While a PINN-based picking of valid transport models has important implications for the development of effective methods for controlling emission of volatiles from paper materials, PINNs represent a versatile mathematical tool to validate or refute the capability of PDE-based theoretical models to describe experimental data. • PINNs evaluate sorption kinetics in porous materials. • Focus: Transport of organic volatiles in cellulose. • Pseudo first-order model suits organic volatiles. • Predicting transport of volatiles through paper. [ABSTRACT FROM AUTHOR]
- Published
- 2024
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17. The use of recycled paper processing residues in making porous brick with reduced thermal conductivity
- Author
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Sutcu, Mucahit and Akkurt, Sedat
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PAPER recycling , *POROUS materials , *THERMAL conductivity , *LIGHTWEIGHT concrete , *SCANNING electron microscopy , *GRANULATION , *PROPERTIES of matter - Abstract
Abstract: Production of porous and light-weight bricks with reduced thermal conductivity and acceptable compressive strength is accomplished. Paper processing residues were used as an additive to an earthenware brick to produce the pores. SEM-EDS, XRD, XRF and TG-DTA analysis of the paper waste and brick raw material were performed. Mixtures containing brick raw materials and the paper waste were prepared at different proportions (up to 30wt%). The granulated powder mixtures were compressed in a hydraulic press, and the green bodies were dried before firing at 1100°C. Dilatometric behaviours, drying and firing shrinkages were investigated as well as the loss on ignition, bulk density, apparent porosity, water absorption and thermal conductivity values of the fired samples. Their mechanical and microstructural properties were also investigated. The results obtained showed that the use of paper processing residues decreased the fired density of the bricks down to 1.28g/cm3. Compressive strengths of the brick samples produced in this study were higher than that required by the standards. Thermal conductivity of the porous brick produced in this study (<0.4W/mK) showed more than 50% reduction compared to local brick of the same composition (0.8W/mK). Conversion of this product to a perforated brick may reduce its thermal conductivity to very low values. Successful preliminary tests were conducted on an industrial scale. [Copyright &y& Elsevier]
- Published
- 2009
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18. Porous cellulose paper as a light out coupling medium for organic light-emitting diodes.
- Author
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Lee, Jeong Hun, Kang, Sohyeon, Park, Nae-Man, Shin, Jin-Wook, Joo, Chul Woong, Lee, Jonghee, Ahn, Seong-Deok, Kang, Seung-Youl, and Moon, Jaehyun
- Subjects
ORGANIC light emitting diodes ,POROUS materials ,CELLULOSE ,TRANSMITTANCE (Physics) ,ANGULAR distribution (Nuclear physics) - Abstract
Porous nanocellulose paper was fabricated and applied as a light outcoupling medium. The nanocellulose papers were prepared using cellulose powder and a high-pressure homogenizing process. The translucent nanocellulose paper had high total transmittance and haze, and gave off diffuse light when the incident light passes through it. Through the application of the fabricated nanocellulose paper on the external surfaces of organic light-emitting diode (OLED) devices, it was possible not only to enhance the luminous efficiency but also to widen the angular light distribution. As this paper is intrinsically flexible, it can be applied to various forms of light sources bearing curvature. [ABSTRACT FROM AUTHOR]
- Published
- 2018
- Full Text
- View/download PDF
19. Modeling water imbibition into coated and uncoated papers.
- Author
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Ghanbarian, Behzad, Aslannejad, Hamed, and Raoof, Amir
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- *
HYDRAULICS , *PERMEABILITY , *POROUS materials , *PORE size distribution , *PROBABILITY density function - Abstract
Modeling morphological and hydraulic properties of thin porous media, such as filter layers and papers is highly relevant to various industries. In our previous studies, the X-ray tomography and FIB-SEM methods were applied to capture micro- and nano-scale pores in uncoated paper and coated layer, respectively. Here, the reconstructed pore structures were used to investigate two-phase water imbibition in these porous media. The obtained pore size distributions showed a log-normal probability density function. Such a distribution, together with concepts from critical path analysis and percolation theory, was applied to calculate relative permeability over a wide range of water saturations. Comparison with pore-scale numerical simulations showed the capability of this method to estimate water relative permeability for coated and uncoated papers. [ABSTRACT FROM AUTHOR]
- Published
- 2018
- Full Text
- View/download PDF
20. Nanowire‐decorated SiC foam from tissue paper and silicon powder by filter‐pressing.
- Author
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Wilson, Praveen, Vijayan, Sujith, and Prabhakaran, Kuttan
- Subjects
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SILICON nanowires , *HEAT treatment , *YOUNG'S modulus , *SILICON , *POROUS materials , *COMPRESSIVE strength - Abstract
A facile and scalable method for the preparation of low‐density SiC foam from tissue paper and silicon powder is reported. The co‐dispersion of pulp‐containing tissue paper micro‐ribbons and silicon powder is coagulated by adjusting the pH to 3.5. The silicon particles adhere to the tissue paper micro‐ribbons during the coagulation. The coagulated co‐dispersion on filter‐pressing consolidates the silicon particle‐decorated tissue paper micro‐ribbons and orients them perpendicular to the filter‐pressing direction. The filter‐pressed body on drying followed by heat treatment at 1600°C in inert atmosphere produces SiC foam. The tissue paper micro‐ribbons retain their morphology during carbonization as well as high‐temperature reaction with the silicon. The enormous growth of carbon‐rich SiC nanowires is observed on the SiC micro‐ribbons. The random orientation of SiC micro‐ribbons in the X‐Y plane with the hairy nanowires on the surface and their stacking in the Z‐direction produces a porosity of ~94 vol.% with pore sizes in the range of 0.08 to 20 µm. The SiC foam shows a compressive strength and Young's modulus of 0.22 and 5.5 MPa, respectively. The thermal conductivity decreases from 0.11 to 0.07 W m−1 K−1 when temperature increases from 25°C to 350°C. [ABSTRACT FROM AUTHOR]
- Published
- 2020
- Full Text
- View/download PDF
21. Effect of microporous layer on MacMullin number of carbon paper gas diffusion layer
- Author
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Martínez-Rodríguez, Michael J., Cui, Tong, Shimpalee, Sirivatch, Seraphin, Supapan, Duong, Binh, and Van Zee, J.W.
- Subjects
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CARBON paper , *DIFFUSION , *POROUS materials , *PORE size distribution , *FUEL cells , *HYDROPHOBIC compounds , *SCANNING electron microscopy - Abstract
Abstract: The effect of the microporous layer (MPL) and wet proofing on the MacMullin number has been evaluated for a custom series of Toray TGP-H-060 carbon paper gas diffusion layer (GDL). Complementary characterizations for these GDLs were performed by using scanning electron microscopy (SEM) images, pore size distribution (PSD) and fuel cell performance. The GDLs were customized by the addition of a microporous layer (MPL) and the treatment of, either or both, the substrate and MPL with 10% and 40% hydrophobic agent. SEM images correlated very well with the data shown for PSD. Distinction between the substrate layer and the MPL were clearly shown as two different slopes in the integral distribution and two different peaks in the differential distribution. The MacMullin number increased with increase in wet proofing but decreased with the addition of the MPL. The MacMullin number is a key parameter that contains the missing information for the path length in GDLs, which is generally approximated with the Bruggeman expression. The results provided an overview for the interpretation of the combined effect of the substrate and MPL properties as well as the cell operating conditions. [Copyright &y& Elsevier]
- Published
- 2012
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22. A porous Co3O4-carbon paper electrode enabling nearly 100% electrocatalytic reduction of nitrate to ammonia.
- Author
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Xufeng Rao, Jiaying Yan, Koji Yokoyama, Xiaolin Shao, Chihiro Inoue, Mei-fang Chien, and Yuyu Liu
- Subjects
POROUS materials ,AMMONIA ,NITRATES ,ELECTRODES ,CATALYSTS - Abstract
Co
3 O4 was synthesized on carbon paper (CP) using a facile method to improve electrochemical nitrate-toammonia conversion efficiency. The resulting Co3 O4 -CP electrode demonstrated an exceptional Faradaic efficiency of almost 100% across a broad range of application conditions, with a peak NH3 yield of 3.43 mmol h-1 cm-2 (2.25 mol gCo-1 h-1 ). [ABSTRACT FROM AUTHOR]- Published
- 2023
- Full Text
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23. Optimization of pore structure and wet tribological properties of paper-based friction materials using chemical foaming technology.
- Author
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Li, Chang, Fei, Jie, Zhou, Enzhi, Lu, Rui, Cai, Xiaohang, Fu, Yewei, and Li, Hejun
- Subjects
POROSITY ,INDUSTRIAL chemistry ,POROUS materials ,SURFACE active agents ,FRICTION materials ,SLIDING friction ,FOAM - Abstract
Paper-based friction materials are porous materials that exhibit anisotropy; they exhibit random pore sizes and quantities during their preparation, thereby rendering the control of their pore structure difficult. Composites with different pore structures are obtained by introducing chemical foaming technology during their preparation to regulate their pore structure and investigate the effect of pore structure on the properties of paper-based friction materials. The results indicate that the skeleton density, total pore area, average pore diameter, and porosity of the materials increase after chemical foaming treatment, showing a more open pore structure. The addition of an organic chemical foaming agent improves the curing degree of the matrix significantly. Consequently, the thermal stability of the materials improves significantly, and the hardness and elastic modulus of the matrix increase by 73.7% and 49.4%, respectively. The dynamic friction coefficient increases and the wear rate is reduced considerably after optimizing the pore structure. The wear rate, in particular, decreases by 47.7% from 2.83 × 10
−8 to 1.48 × 10−8 cm3 /J as the foaming agent content increases. Most importantly, this study provides an effective method to regulate the pore structure of wet friction materials, which is conducive to achieving the desired tribological properties. [ABSTRACT FROM AUTHOR]- Published
- 2022
- Full Text
- View/download PDF
24. Measurement of thermal conductivity and heat pipe effect in hydrophilic and hydrophobic carbon papers
- Author
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Wang, Yun and Gundevia, Mehernosh
- Subjects
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HEAT pipes , *HYDROPHILIC compounds , *CARBON paper , *THERMAL conductivity , *POROUS materials , *HEAT equation , *CAPILLARY liquid chromatography - Abstract
Abstract: In this paper, we present an experimental study on measurement of the thermal conductivity and heat pipe effect in both hydrophilic and hydrophobic (Toray TGP-H60) carbon papers (around 200μm thickness) with/out liquid water. An experimental setup is developed for measuring thermal conductance at different liquid water contents and temperatures without dissembling the testing device for water addition. Theoretical analysis is also performed to evaluate the apparent conductance of heat pipe effect. We found that liquid water presence inside these materials increases the overall thermal conductivity. At high temperature around 80°C, the heat pipe effect is evident for the hydrophilic paper; while for the hydrophobic one, the heat pipe effect is found to be smaller. The distinction is likely due to the different patterns of the capillary liquid flow in the two media. For the hydrophobic paper, liquid water flows back to the evaporation side when the breakthrough pressure is reached and flow is through preferred routes of small flow resistance. As a result, heat pipe effect is active only in part of the medium, therefore smaller than that in the hydrophilic one. The results are important for understanding the heat transfer phenomena occurring in porous media and effects of material surface property. [Copyright &y& Elsevier]
- Published
- 2013
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- View/download PDF
25. A micro contact model for electrical contact resistance prediction between roughness surface and carbon fiber paper.
- Author
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Qiu, Diankai, Peng, Linfa, Yi, Peiyun, and Lai, Xinmin
- Subjects
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CARBON fibers , *SURFACE roughness , *CONTACT resistance (Materials science) , *POROUS materials , *DEFORMATIONS (Mechanics) , *MECHANICAL engineering - Abstract
Electrical contact resistance (ECR) at the interface is of significant importance in many fields of science and engineering. Current methods for contact resistance estimation are based on the typical nearly incompressible rough surfaces, which is not suitable for porous material with large deformation in the compression process. The objective of this work is to build an analytical model for ECR between solid material and porous material, for example, which could be used to predict power loss between carbon fiber paper and bipolar plate in the fuel cell. First, mathematical description of solid roughness surface is built by classic Greenwood and Williamson model. Considering the porous structure, carbon fiber paper is modeled by multi-layer construction based on random line network model. Effect of large compression of carbon paper on contact behavior is furtherly given necessary attention in this study. Contact pressure and resistance are calculated based on statistical methods with consideration of multi-deformation states. Then, experiments are carried out to validate the numerical model. The results show good agreements with the numerical model. Finally, influences of carbon paper compression and main parameters are systematically discussed based on the numerical model. The model developed will enhance our understanding regarding the relation between contact pressure and contact resistance at the interface for solid material and fiber-structure material. [ABSTRACT FROM AUTHOR]
- Published
- 2017
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- View/download PDF
26. Application of NMR for quantification of magnetic nanoparticles and development of paper-based assay
- Author
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M. A. Uymin, I. V. Zubarev, A. S. Minin, I. V. Byzov, M. B. Rayev, A. V. Volegov, P. V. Khramtsov, A. A. Mysik, A. Ye. Yermakov, and S. V. Zhakov
- Subjects
MAGNETIC PARTICLE ,History ,TRANSVERSE RELAXATION TIME ,Materials science ,PROTEINS ,LOW CONCENTRATIONS ,BIOLOGY AND MEDICINE ,Nanotechnology ,Paper based ,equipment and supplies ,Computer Science Applications ,Education ,POROUS MATERIALS ,MAGNETIC NANO-PARTICLES ,NANOMAGNETICS ,NITROCELLULOSE MEMBRANES ,NANOPARTICLES ,Magnetic nanoparticles ,NUCLEAR MAGNETIC RESONANCE ,SMALL CONCENTRATION ,BIOLOGICALLY ACTIVE MOLECULES - Abstract
H1 NMR relaxometry is a method that is extremely sensitive to the presence of magnetic nanoparticles, which significantly affect the transverse relaxation time of the water proton. Accordingly, the use of magnetic nanoparticles as labels allows detection of even extremely small amounts of the test substance. This paper analyzes the prospects for applying the method of solid-phase NMR-relaxometric determination of biologically active molecules. The nitrocellulose membranes are chosen as a solid phase and nanoparticles based on iron core with a carbon shell are used as magnetic labels. The possibility of detecting small concentrations of magnetic particles in porous medium is demonstrated. Finally, the ability to detect extremely low concentrations of an analyte, in this case, streptavidin protein (0.5 ng/ml to 100 ng/ml), which is actively used in various fields of biology and medicine, is demonstrated. © Published under licence by IOP Publishing Ltd. Russian Science Foundation, RSF: 17-15-01116 The work was carried out within the Russian Science Foundation project 17-15-01116. equipment of the Ural Center for Shared Use Modern nanotechnology UrFU was used.
- Published
- 2019
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27. Hierarchical ultrathin NiAl layered double hydroxide nanosheet arrays on carbon nanotube paper as advanced hybrid electrode for high performance hybrid capacitors.
- Author
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Zhang, Luojiang, Chen, Rui, Hui, Kwun Nam, Hui, Kwan San, and Lee, Haiwon
- Subjects
- *
THIN films , *NICKEL-aluminum alloys , *CARBON nanotubes , *LAYERED double hydroxides , *CAPACITORS , *POROUS materials - Abstract
To effectively improve the power density and rate capability of layered double hydroxide (LDH) based supercapacitors, a hybrid supercapacitor (HSC) comprising of hierarchical ultrathin NiAl-LDH nanosheet arrays on carbon nanotube paper (CNP-LDH) is developed with porous graphene nanosheets as the negative electrode for the first time. SEM image shows that hierarchical NiAl LDH nanosheet arrays are assembled by numerous ultrathin nanosheets with thickness of a few to tens of nanometers. Remarkably, with an operating voltage of 1.6 V, the HSC possesses a high energy density of 50.0 Wh kg −1 at an average power density of 467 W kg −1 . Even at a fast discharging time of 3.9 s, a high energy density (23.3 Wh kg −1 ) could also be retained at a power density of 21.5 kW kg −1 . Moreover, the HSC exhibits cycling stability with a retention rate of 78% after 5000-cycle charge-discharge test at 5 A g −1 . The results inspire us to propose our high-performance CNP-LDH as a promising electrode for energy storage applications. [ABSTRACT FROM AUTHOR]
- Published
- 2017
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28. Effect of protein adsorption on the radial wicking of blood droplets in paper.
- Author
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Hertaeg, Michael J., Garnier, Gil, and Tabor, Rico F.
- Subjects
- *
POROUS materials , *BIOLOGICAL fluid dynamics , *BLOOD volume , *SURFACE tension , *CAPILLARY flow - Abstract
Hypotheses (1) The equilibrium size and characteristics of a radially wicked fluid on porous material such as paper is expected to be dependent on the fluid properties and therefore could serve as a diagnostic tool. (2) The change in wicked stain size between biological fluids is dependent on a change in solid-liquid surface interfacial energy due to protein adsorption. Experiments Sessile droplets of increasing volume of blood, its components, and model fluids were deposited onto paper and the equilibrium stain size after coming to a halt was recorded. The contact angle of fluid droplets on model cellulose surfaces was measured to quantify the effect that blood protein adsorption at the solid-liquid interface has on radially wicked equilibrium size. Finally the significance of droplet evaporation for the time scale of interest was analysed. Findings The final stain area of all fluids tested on paper scales remarkably linearly with droplet volume. Different fluids were compared and the gradient of this linear relation was measured. Model fluids varying in surface tension and viscosity all behave similarly and exhibit a constant gradient. Blood and its components produce smaller stains, demonstrated by lower gradients. The gradient is a function of protein concentration, thus the mechanism of this phenomenon was identified as protein adsorption at the cellulose-liquid interface. The slope of the area/volume relationship for droplets is an important quantitative mechanistic variable. [ABSTRACT FROM AUTHOR]
- Published
- 2018
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29. Development of Paper Sludge Ash-Based Geopolymer and Application to Treatment of Hazardous Water Contaminated with Radioisotopes.
- Author
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Zhuguo Li, Toshihiko Ohnuki, and Ko Ikeda
- Subjects
- *
ASH (Combustion product) , *POLYMERS , *TEMPERATURE measurements , *ABSORPTION , *POROUS materials - Abstract
Ambient temperature geopolymerization of paper sludge ashes (PS-ashes) discharged from paper mills was studied by means of scanning electron microscopy (SEM), X-ray diffraction (XRD), induction coupled plasma atomic emission spectrometry (ICP-AES), and X-ray absorption near edge structure (XANES). Two varieties of alkaline liquors were used in the PS-ash based geopolymers, corresponding to aqueous Na-metasilicate and Na-disilicate compositions. PS-ashes were found to be semi-crystalline and to have porous structures that make it possible to absorb much liquor. Flexural strengths of PS-ash-based geopolymers with liquor/filler ratios (L/F) of 1.0-1.5 ranged from 0.82 to 1.51 MPa at 4 weeks age, depending on PS-ashes and liquors used. The reaction process of the constituent minerals of the PS-ash is discussed. Furthermore, we attempted to solidify hazardous water contaminated with radioisotopes. Non-radioactive strontium and cesium nitrates were added as surrogates at a dosage of 1% into the PS-ash-based geopolymers. Generally, high immobilization ratios up to 99.89% and 98.77% were achieved for Sr2+ and Cs+, respectively, depending on the source of PS-ashes, alkaline liquors, and material ages. However, in some cases, poor immobilization ratios were encountered, and we further discussed the causes of the instability of derived geopolymer gels on the basis of XANES spectra. [ABSTRACT FROM AUTHOR]
- Published
- 2016
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30. Al2O3/Cu-O composites fabricated by pressureless infiltration of paper-derived Al2O3 porous preforms.
- Author
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Pfeiffer, Stefan, Lorenz, Hannes, Fu, Zongwen, Fey, Tobias, Greil, Peter, and Travitzky, Nahum
- Subjects
- *
ALUMINUM oxide , *COMPOSITE materials , *POROUS materials , *COPPER alloys , *FABRICATION (Manufacturing) - Abstract
Abstract Al 2 O 3 /Cu-O composites were fabricated from the paper-derived alumina matrix infiltrated with a Cu-3.2 wt% O alloy. Paper-derived alumina preforms with an open porosity ranging from ∼ 14 to ∼ 25 vol% were prepared by sintering of alumina-loaded preceramic papers at 1600 °C for 4 h. Pressureless infiltration at 1320 °C for 4 h of the preforms with Cu–O alloy resulted in the nearly dense materials with good mechanical and electrical properties, e.g. fracture toughness up to 6 MPa m0.5, four-point-bending strength up to 342 MPa, Young's modulus up to 281 GPa and electrical conductivity up to 2 MS/m depending on the volume fraction of copper alloy in the composites. The technological capability of this approach was demonstrated using prototypes in various engineering fields fabricated by lamination, corrugating and Laminated Object Manufacturing (LOM) methods. [ABSTRACT FROM AUTHOR]
- Published
- 2018
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- View/download PDF
31. Mathematical model for mixing in a paper-based channel and applications to the generation of a concentration gradient.
- Author
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Jang, Ilhoon, Kim, Gangjune, and Song, Simon
- Subjects
- *
CHANNEL flow , *POROUS materials , *TRANSPORT equation , *NUMERICAL analysis , *CONCENTRATION gradient - Abstract
A paper-based channel is a useful platform for the facile development of analytical devices implementing various chemical or biological reactions. To improve the analytical performance for various applications, it was necessary to analyze the detailed mixing characteristics within a paper-based channel. In this paper, we proposed a mathematical model to predict a concentration field created as a result of the imbibition of multiple fluids within a porous material. Interestingly, we found that the model exhibited a constant interdiffusion width within a paper-based channel even though the flow front velocity decreased over time. We were able to verify that our model accurately predicted the concentration field by comparing the experimental and numerical results for mixing in a 2 inlet-channel. Finally, we designed and fabricated paper-based channels to generate two (linear and non-linear) concentration gradients based on predictions made by the model. Both the experimental and numerical results were in good agreement, demonstrating that our model was accurate and useful for developing a paper-based analytical device utilizing the mixing characteristics of a sample and reagent flow system. [ABSTRACT FROM AUTHOR]
- Published
- 2018
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32. Reagentless fabrication of a porous graphene-like electrochemical device from phenolic paper using laser-scribing
- Author
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Siervo, Abner de, 1972, Araujo, William Reis de, 1991, and UNIVERSIDADE ESTADUAL DE CAMPINAS
- Subjects
Laser pyrolysis ,Materiais porosos ,Grafeno ,Sensores eletroquímicos ,Electrochemical sensors ,Artigo original ,Porous materials ,Graphene domains ,Graphene ,Disposable devices - Abstract
Agradecimentos: We acknowledge financial support from the Brazilian agencies FAPESP (Grant Numbers: 2017/10522-5, 2018/16250-0, 2018/08782-1, 2009/054066-7, and 2007/54829-5), CAPES (Grant Number 3359/2014 Pró-Forenses Edital 25/2014), CNPq (grant numbers: 444498/2014-1, 438828/2018- 6, 306690/2015-2, and 305605/2017-8) and INCTBio (573672/2008-3). Additionally, the authors are grateful to Professor Dr. Susana Torresi and A. C. Silva for contact angle measurements. We thank Central Analítica e Central Multiusuário at IQ-USP and IQ-UNICAMP for providing the infrastructure Abstract: This study fabricated a portable, high-performance, and reagentless electrochemical devices using CO2 laser-scribing process, which allowed localized carbonization of a non-conductive and low-cost polymer platform, i.e., phenolic-paper. The carbonized material was extensively characterized by Raman spectroscopy, XPS, XRD, SEM, and electrochemical impedance spectroscopy. The carbon-based electrodes were obtained from the photothermal process induced by CO2 laser radiation and subsequently subjected to electrochemical treatment to fabricate a functional material with excellent conductivity and low charge-transfer resistance. Additionally, the laser-scribed electrodes presented a porous structure with graphene-like domains, thus indicating both potential for on-site electroanalytical applications and better performance than conventional carbon electrodes FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULO - FAPESP COORDENAÇÃO DE APERFEIÇOAMENTO DE PESSOAL DE NÍVEL SUPERIOR - CAPES CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO - CNPQ Fechado
- Published
- 2020
33. Liquid spreading on solid surfaces and penetration into porous matrices: Coated and uncoated papers.
- Author
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Rosenholm, Jarl B.
- Subjects
- *
POROUS materials , *WETTING , *ACCELERATION (Mechanics) , *PAPER coatings , *CHEMICAL equilibrium , *VISCOSITY , *POWER law (Mathematics) - Abstract
Liquid spreading on solid surfaces and penetration into porous matrices (powders and coated papers) are investigated. The influence of chemical and structural heterogeneity on equilibrium and dynamic surface wetting is evaluated both experimentally and theoretically. Single capillary systems are used to identify the predominating mechanisms for acceleration, momentum, inertial and viscous liquid penetration. Different stages of vertical and horizontal penetration of liquids from non-limited, restricted (sessile drop) and cut-off sources into powders and papers are evaluated with reference to a range of frequently used models. For all types of liquid transport power-law exponents are used to relate all observations. The applicability of models from which the exponents are derived is discussed. Results are compared to theoretical predictions for liquid penetration. Models are of general validity, but the focus is placed on probe liquid spreading on and penetrating into coated and uncoated papers. This sets a particular challenge, since papers are heterogeneous layered composites of powder compacts on fibrous network. For the evaluation of models published results are supported by extended original results. [ABSTRACT FROM AUTHOR]
- Published
- 2015
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34. Performance of single-layer paper-based co-laminar flow microbial fuel cells.
- Author
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Lee, Cheon Ho, Ha, Hongyoung, Ahn, Yoomin, and Liu, Hong
- Subjects
- *
MICROBIAL fuel cells , *UNSTEADY flow , *POROUS materials , *CARBON electrodes , *FUEL cells , *ELECTRON donors - Abstract
This paper presents a novel design and operation of microbial fuel cells (ΜFCs), which contain monolayer paper-based substrate/electrodes and microchannels with co-laminar flow. The electrodes with multi-wall carbon nanotubes are fabricated by the screen-printing method and the microchannels are patterned using photo-lithography. A double-inlet and diverging channel design is incorporated in the fuel cell configuration and demonstrated significantly improved performance. The fluid flows of electrolytes through the porous paper media are simulated using steady-state and transient computational fluid dynamics The best performance is achieved under the following conditions: an electroactive microbial (S. oneidensis) concentration of OD 600 1.5, 50 mM electron donor (lactate), and direct immobilized of the inoculum on the anode surface. The developed MFCs achieves a peak power density of 19.4 ± 0.23 μW cm−2 and maximum current density of 190.4 ± 1.39 μA cm−2, surpassing the performance of all previously reported paper-based single MFCs that utilize paper-based electrodes. In addition, hybrid-type MFCs that containing enzymatic air-breathing cathodes are investigated to enhance their performance. The novel paper based self-pumping MFC has the potential to make lab-on-a-chip type portable medical diagnosis devices with integrated power sources practical and feasible. [Display omitted] • A paper-based membraneless co-laminar flow microbial fuel cell was developed. • Microfluidic fuel cell was micromachined as a monolayer structure in paper substrate. • Co-laminar flow of the electrolyte through paper was simulated using CFD analysis. • Inoculation method, anolyte type, and cell configuration were tested and optimized. • A hybrid microbial-enzymatic fuel cell was also examined for performance improvement. [ABSTRACT FROM AUTHOR]
- Published
- 2023
- Full Text
- View/download PDF
35. A comparative study of paper-based microfluidic devices with respect to channel geometry.
- Author
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Jafry, Ali Turab, Lim, Hosub, Kang, Seong Il, Suk, Ji Won, and Lee, Jinkee
- Subjects
- *
MICROFLUIDIC devices , *FABRICATION (Manufacturing) , *ENVIRONMENTAL monitoring , *HYDRODYNAMICS , *PHOTOLITHOGRAPHY , *POROUS materials - Abstract
Since 2007, the world of microfluidics saw an emergence of a new era of low cost, simple, quick fabrication, abundantly available, and environmentally friendly microfluidic paper-based analytical devices (μPADs) capable of clinical diagnostics, food quality control as well as environmental monitoring. Although many fabrication techniques have evolved as a result of its broad application spectrum and ease of use, the technology has still barely scratched the surface of its potential in terms of its underlying fundamental principle, i.e., fluid flow analysis. In this study, we report the comparison of flow profile attained by using two of the most promising techniques of photolithography and wax printing from a hydrodynamic point of view. A modified protocol for synthesizing an epoxy based negative photoresist (SU-8) channel and wax-based channel was created by optimizing a few process parameters of our equipment. Water and oil (oleic acid) are selected as the hydrophilic and hydrophobic fluids, respectively, and their flow was analyzed in straight channels using a paper device. A new approach to vary the flow velocity is described in detail involving cylindrical dots as the resistance inside the paper channel. Observing the length-time curve for the two fluids, it becomes evident that both follow the Lucas–Washburn equation if the width of the channel is large enough. Various configurations of dots indicate that different longitudinal flow velocity implying its application in simultaneous addition of chemicals without the need to change the channel width or length. [ABSTRACT FROM AUTHOR]
- Published
- 2016
- Full Text
- View/download PDF
36. Dual‐Scale Spiral Material for Balancing High Load Bearing and Sound Absorption.
- Author
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Yu, Chenlei, Duan, Mingyu, Ti, Fei, Xin, Fengxian, Zhao, Guiping, Lu, Tian Jian, Yu, Runpei, Li, Moxiao, and Chen, Xin
- Subjects
ABSORPTION of sound ,POROUS materials ,LIGHTWEIGHT materials ,ALUMINUM foam ,HELICAL structure ,FOAM - Abstract
Porous materials with sound absorption and load‐bearing capabilities are in demand in engineering fields like aviation and rail transportation. However, achieving both properties simultaneously is challenging due to the trade‐off between interconnected pores for sound absorption and mechanical strength. Inspired by quilling art, a novel design using spiral material formed by rolling planar materials into helical structures is proposed. Experimental results show high structural strength through self‐locking mechanisms, while double porosities from interlayer spiral slits and aligned submillimeter pores provide excellent sound absorption. These spiral sheets surpass foam aluminum in specific strength (up to 5.1 MPa) and approach aerogels in sound absorption (average coefficient of 0.93 within 0–6400 Hz). With its adaptability to various planar materials, this spiral design allows for hybrid combinations of different materials for multi‐functionality, paving the way for designing advanced, lightweight porous materials for broad applications. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
37. Colloidal silica nanoparticle-assisted structural control of cellulose nanofiber paper separators for lithium-ion batteries.
- Author
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Kim, Jeong-Hoon, Kim, Jung-Hwan, Choi, Eun-Sun, Yu, Hyung Kyun, Kim, Jong Hun, Wu, Qinglin, Chun, Sang-Jin, Lee, Sun-Young, and Lee, Sang-Young
- Subjects
- *
SILICA gel , *NANOPARTICLES , *CELLULOSE , *NANOFIBERS , *LITHIUM-ion batteries , *POROUS materials , *MACHINE separators - Abstract
Abstract: Porous structure-tuned cellulose nanofiber paper separators (designated as S-CNP separators) are demonstrated as a promising alternative to commercial polyolefin separators for use in lithium-ion batteries. A new architectural strategy based on colloidal silica (SiO2) nanoparticle-assisted structural control is presented to overcome the difficulty in forming controllable porous structure of pure cellulose nanofiber paper separators (designated as CNP separators) from densely-packed cellulose nanofibers (CNFs). The new S-CNP separators proposed herein incorporate SiO2 nanoparticles as a CNF-disassembling agent (i.e., as non-conductive spacer particles). This structural uniqueness allows loose packing of CNFs, thereby facilitating the evolution of more porous structure. The unusual porous structure of S-CNP separators can be fine-tuned by varying SiO2 contents in the CNF suspension. Notably, the S-CNP separator (fabricated with 5 wt.% SiO2 content) exhibits the highest ionic conduction due to the well-balanced combination of nanoporous structure and separator thickness, thus contributing to excellent cell performance. This study underlines that the colloidal SiO2 nanoparticle-directed structural tuning of CNPs offers a promising route for the fabrication of advanced paper separators with optimized attributes and functionality. [Copyright &y& Elsevier]
- Published
- 2013
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38. Pulsed laser deposition-assisted synthesis of porous WP2 nanosheet arrays integrated on graphite paper as a 3D flexible cathode for efficient hydrogen evolution.
- Author
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Pi, Mingyu, Guo, Weimeng, Wu, Tianli, Wang, Xiaodeng, Wang, Shuxia, Chen, Shijian, and Zhang, Dingke
- Subjects
- *
POROUS materials , *HYDROGEN evolution reactions , *CATALYTIC activity , *CATHODES , *PHOSPHIDES , *PULSED laser deposition - Abstract
Herein, porous WP 2 nanosheet arrays integrated on graphite paper (P-WP 2 NSs/GP) as 3D flexible cathode for electrocatalytic hydrogen evolution reaction (HER) are prepared by in situ phosphidation via vacuum encapsulation assisted by pulsed laser deposition technique. Compared to the electrode without pre-deposition process, the enhanced catalytic activities are attributed to the increased effective catalyst loading and the reinforced charge transport kinetics. The results make the present P-WP 2 NSs/GP as a promising cathode for energy conversion and paves a new way for designing and fabricating efficient electrodes toward HER. [ABSTRACT FROM AUTHOR]
- Published
- 2017
- Full Text
- View/download PDF
39. Electrochemical capacitor performance of TiO2 nanostructures and porous MnO2 composite supported on carbon fiber paper.
- Author
-
Liu, Xiao Ying, Chen, Cheng, Zhang, Yu Xin, and Zhou, Ming
- Subjects
- *
SUPERCAPACITOR performance , *TITANIUM dioxide nanoparticles , *MANGANESE dioxide , *POROUS materials , *CARBON fibers - Abstract
Titania-based nanostructures and porous MnO 2 layer are deposited onto carbon fiber paper (CFP) conductive support using hydrothermal method. TiO 2 nanoparticles and leaf-like Na 2 Ti 3 O 7 nanosheets are synthesized through the hydrolysis of TiF 4 and post-treatment in NaOH aqueous solution. Electrochemical tests reveal that CFP@TiO 2 @MnO 2 has a better performance with areal specific capacitance of 744 mF cm −2 at 0.25 mA cm −2 , compared with that (600 mF cm −2 ) of CFP@Na 2 Ti 3 O 7 @MnO 2 . The possible mechanism is that TiO 2 has higher surface area and better electronic conductivity than those of Na 2 Ti 3 O 7 . However, the cycling performance of CFP@TiO 2 @MnO 2 is limited with capacitance retention of 17.7% after 1000 cycles while CFP@Na 2 Ti 3 O 7 @MnO 2 keeps this retention up to 59.9%. [ABSTRACT FROM AUTHOR]
- Published
- 2017
- Full Text
- View/download PDF
40. All-Printed Microfluidic–Electrochemical Devices for Glucose Detection.
- Author
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Wang, Zexi, Zhang, Zhiyi, and Xu, Changqing
- Subjects
POLYMER blends ,POROUS materials ,POLYETHYLENE terephthalate ,DETECTION limit ,ELECTRODES - Abstract
Free-standing capillary microfluidic channels were directly printed over printed electrodes using a particle/polymer mixture to fabricate microfluidic–electrochemical devices on polyethylene terephthalate (PET) films. Printed devices with no electrode modification were demonstrated to have the lowest limit of detection (LOD) of 7 μM for sensing glucose. The study shows that both a low polymer concentration in the mixture for printing the microfluidic channels and surface modification of the printed microfluidic channels using 3-aminopropyltrimethoxysilane can substantially boost the device's performance. It also shows that both device structure and enzyme doping level of the devices play an important role in ensuring the best performance of the devices under various testing conditions. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
41. Estimating effective thermal conductivity in carbon paper diffusion media
- Author
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Zamel, Nada, Li, Xianguo, Shen, Jun, Becker, Jürgen, and Wiegmann, Andreas
- Subjects
- *
THERMAL conductivity , *COMMERCIALIZATION , *PROTON exchange membrane fuel cells , *HEAT transfer , *DIFFUSION , *ESTIMATION theory , *INTEGRATED software , *POROUS materials - Abstract
Abstract: Heat management is crucial to polymer electrolyte membrane (PEM) fuel cell commercialization. Numerical modeling is often used to simulate heat transfer in the various components of the cell and specifically the gas diffusion layer (GDL). Due to the porous nature of the gas diffusion layer and its complexity of anisotropy, the effect of the structure on the thermal conductivity is usually taken into account by introducing an effective thermal conductivity. In this study, the effective thermal conductivity of carbon paper diffusion media was estimated numerically. Carbon paper is often used as the GDL in PEM fuel cells due to its ability to efficiently transport electrons, heat and gaseous species. Using the GeoDict code, a realistic three-dimensional pore morphology of carbon paper was used as the modeling domain and the governing mathematical equations were solved using the commercial software package Fluent (6.3.26) and the ThermoDict solver. The geometrical effects on the effective thermal conductivity were investigated for different geometries. It was found that the effective thermal conductivity is highly sensitive to the geometry of the porous material under investigation. The effective thermal conductivity is much larger in the in-plane direction when compared with the value in the through-plane direction. Further, the change of the effective thermal conductivity due to porosity and compression was studied. Finally, correlations for the through-plane and in-plane effective thermal conductivity were developed. [Copyright &y& Elsevier]
- Published
- 2010
- Full Text
- View/download PDF
42. PREPARATION AND CHARACTERISTICS OF A PAPER-BASED ULTRAFILTRATION MEMBRANE.
- Author
-
Jian Wang, Xiaofan Zhou, and Jinxia Ma
- Subjects
ULTRAFILTRATION ,ARTIFICIAL membranes ,PAPERMAKING ,ADHESIVES ,COATING processes ,POROUS materials ,WATER vapor transport - Abstract
A novel process involving a paper-based ultrafiltration (UF) membrane was developed via paper coating technology. The membrane employed a paper sheet as support layer and a coated thin film layer of adhesive. The proper selection of paper sheet support layer was crucial to the performance of the ultrafiltration membrane. A paper sheet with beating degree of 85°SR and basis weight of 50g/m² was chosen as the support. PVA was chosen as the adhesive. The paper-based ultrafiltration membrane achieved high retention performance while using a simple production process and keeping the production cost low. Disadvantages of the membrane included low porosity and low pure water flux. So further investigation is still needed to produce a fully satisfactory paper-based ultrafiltration membrane. [ABSTRACT FROM AUTHOR]
- Published
- 2012
- Full Text
- View/download PDF
43. Printed and unprinted office paper, by near-ambient pressure XPS.
- Author
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Shah, Dhruv, Bahr, Stephan, Dietrich, Paul, Meyer, Michael, Thißen, Andreas, and Linford, Matthew R.
- Subjects
X-ray photoelectron spectroscopy ,POROUS materials ,BLUE light ,SILICON solar cells ,PRESSURE - Abstract
Near-ambient pressure x-ray photoelectron spectroscopy (NAP-XPS) is a less-traditional form of XPS that allows samples to be analyzed at relatively high pressures, i.e., at ca. 2500 Pa, or even higher in some cases. With NAP-XPS, XPS can probe moderately volatile liquids, biological samples, porous materials, and/or polymeric materials that outgas significantly. In this submission, the authors show NAP-XPS survey spectra, and C 1s and O 1s narrow scans of two samples of paper (a white office paper and the nonsticky side of a yellow post-it note). The white office paper was analyzed at three specific positions: an unprinted portion, a light blue letter, and a dark blue letter in the "SPECS" logo. Survey spectra show the presence of carbon, oxygen, nitrogen, and calcium in all the samples. The yellow paper shows a small amount of silicon. Fits to the C 1s and O 1s regions are shown. The O 1s narrow scans are fit with four peaks using a literature approach previously employed for paper and with three peaks in a more ad hoc fashion. The latter approach yields better fits. [ABSTRACT FROM AUTHOR]
- Published
- 2019
- Full Text
- View/download PDF
44. Conversion of paper and xylan into laser-induced graphene for environmentally friendly sensors.
- Author
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Kulyk, Bohdan, Matos, Marina, Silva, Beatriz F.R., Carvalho, Alexandre F., Fernandes, António J.S., Evtuguin, Dmitry V., Fortunato, Elvira, and Costa, Florinda M.
- Subjects
- *
GRAPHENE , *CARBON nanofibers , *POROUS materials , *GRAPHENE synthesis , *CARBON foams , *FILTER paper , *ACTIVATED carbon - Abstract
Laser-induced graphene (LIG) is a foam-like porous material consisting of few-layer graphene obtained by laser irradiation of a wide range of carbon-containing substrates. Among these, the ability to synthesize LIG from paper and other cellulose-related materials is particularly exciting, as it opens the door to a wide assortment of potential applications in the form of low-cost, flexible, and biodegradable devices. Here, the synthesis of this material, dubbed paper-LIG , on different types of filter papers and xylan biopolymer is discussed. In particular, we report the formation of paper-LIG by single-step irradiation, providing an improvement over the conventional multiple lasing approach and giving an explanation of the conditions that allow this simplified synthesis. All the relevant process parameters are covered, assessing their effect on the resulting electrical properties, structure, and morphology. Additionally, we demonstrate the application of LIG obtained from xylan, an abundant and often underutilized biopolymer, for temperature sensing. These results provide a better understanding of the conditions required for the synthesis of highly conductive LIG from paper and related materials, paving the way for its application, with reduced cost and low environmental impact, in fields ranging from biomonitoring to consumer electronics. [Display omitted] • Synthesis of laser-induced graphene from filter paper by a single irradiation step • Synthesis of laser-induced graphene by irradiation of filter paper containing activated charcoal • Laser-induced graphene from a xylan substrate, valorizing this underutilized natural product • Temperature sensor employing laser-induced graphene obtained from modified xylan [ABSTRACT FROM AUTHOR]
- Published
- 2022
- Full Text
- View/download PDF
45. Paper-based electrochemiluminescence origami cyto-device for multiple cancer cells detection using porous AuPd alloy as catalytically promoted nanolabels.
- Author
-
Wu, Ludan, Ma, Chao, Ge, Lei, Kong, Qingkun, Yan, Mei, Ge, Shenguang, and Yu, Jinghua
- Subjects
- *
ELECTROCHEMILUMINESCENCE , *CANCER cells , *CANCER treatment , *POROUS materials , *BIOSENSORS , *GOLD alloys , *MICROFLUIDIC devices , *GOLD electrodes - Abstract
The detection of cancer cells is important and fundamental for cancer diagnosis and therapy, which has attracted considerable interest recently. Although traditional cyto-sensors have been widely explored due to their high sensitivity and selectivity, it is still a challenge to develop a low-cost, portable, disposable, fast, and easy-to-use cancer cell detection method for applying in the field of cancer diagnosis and therapy. Herein, to address these challenges, we developed a microfluidic paper-based electrochemiluminescence origami cyto-device (μ-PECLOC), in which aptamers modified 3D macroporous Au-paper electrodes were employed as the working electrodes and efficient platforms for the specific cancer cells capture. Owing to the effective disproportionation of hydrogen peroxide and specific recognition of mannose on cell surface, concanavalin-A conjugated porous AuPd alloy nanoparticles were introduced into this μ-PECLOC as the catalytically promoted nanolabels for peroxydisulfate ECL system. Under the optimal conditions, the proposed μ-PECLOC exhibited excellent analytical performance with good stability, reproducibility, and accuracy, towards the cyto-sensing of four types of cancer cells indicating the potential applications to facilitate effective and multiple early cancer diagnosis and clinical treatment. [ABSTRACT FROM AUTHOR]
- Published
- 2015
- Full Text
- View/download PDF
46. Graphene functionalized porous Au-paper based electrochemiluminescence device for detection of DNA using luminescent silver nanoparticles coated calcium carbonate/carboxymethyl chitosan hybrid microspheres as labels.
- Author
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Li, Meng, Wang, Yanhu, Zhang, Yan, Yu, Jinghua, Ge, Shenguang, and Yan, Mei
- Subjects
- *
GRAPHENE , *POROUS materials , *ELECTROCHEMILUMINESCENCE , *DNA analysis , *LUMINESCENCE , *SILVER nanoparticles , *CALCIUM carbonate , *CHITOSAN , *MICROSPHERES - Abstract
In the paper, a simple and sensitive electrochemiluminescence (ECL) DNA sensor based on graphene-modified porous Au-paper working electrode (GR/Au-PWE) and calcium carbonate/carboxymethyl chitosan (CaCO3/CMC) hybrid microspheres @ luminescent silver nanoparticles (AgNPs) composites was developed. The GR/Au-PWE with excellent conductivity was successfully prepared for the immobilization of capture probe. The CaCO3/CMC hybrid microspheres were prepared by the precipitation of calcium carbonate in an aqueous solution containing CMC. The AgNPs was synthesized by thermal reduction of silver ions in glycine matrix, taking advantage of the solid-state matrix to control the nucleation and migration of reduced silver atoms. The CaCO3/CMC@AgNPs composites exhibited 3.6 times higher ECL intensity than the pure AgNPs-labeled reporter DNA. Taking advantage of dual-amplification effects, the paper-based DNA sensor could detect the target DNA quantitatively, in the range of 4.0×10−17–5.0×10−11 M, with a limit of detection as low as 8.5×10−18 M, and perform excellent selectivity. The simple, low-cost, sensitive device could be easily applied for point-of-care testing, public health and environmental monitoring in remote regions, developing or developed countries. [ABSTRACT FROM AUTHOR]
- Published
- 2014
- Full Text
- View/download PDF
47. In situ synthesis of Ni/MgO catalysts on inorganic paper-like matrix for methane steam reforming.
- Author
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Miura, Shin, Umemura, Yuuka, Shiratori, Yusuke, and Kitaoka, Takuya
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CHEMICAL synthesis , *MAGNESIUM oxide , *NICKEL catalysts , *INORGANIC compounds , *STEAM reforming , *POROUS materials , *MICROFABRICATION - Abstract
Highlights: [•] Flexible and porous paper-like Ni/MgO catalysts were successfully fabricated. [•] Ni/MgO catalysts were dispersed on the inorganic fiber networks of paper composites. [•] Catalytic steam reforming of methane proceeded efficiently to produce hydrogen. [•] Paper catalysts exhibited much higher performance than conventional solid catalysts. [ABSTRACT FROM AUTHOR]
- Published
- 2013
- Full Text
- View/download PDF
48. High-performance supercapacitor electrodes based on porous flexible carbon nanofiber paper treated by surface chemical etching.
- Author
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Ma, Chang, Li, Yajuan, Shi, Jingli, Song, Yan, and Liu, Lang
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SUPERCAPACITORS , *ELECTRODES , *POROUS materials , *CARBON nanofibers , *SURFACE chemistry , *ELECTRIC capacity - Abstract
Highlights: [•] Porous carbon nanofiber paper was prepared by surface chemical etching. [•] Specific surface area and surface functionality were greatly increased. [•] Carbon nanofiber paper had high specific capacitance of 362Fg− 1. [•] High power density, energy density and good cycling stability were combined. [•] The carbon paper can find applications in desalination, absorption and catalysis. [ABSTRACT FROM AUTHOR]
- Published
- 2014
- Full Text
- View/download PDF
49. Paper-derived hydroxyapatite.
- Author
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Stares, Steferson Luiz, Fredel, Márcio Celso, Greil, Peter, and Travitzky, Nahum
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HYDROXYAPATITE , *POROUS materials , *AQUEOUS solutions , *SUSPENSIONS (Chemistry) , *MICROSTRUCTURE , *MECHANICAL behavior of materials , *STRENGTH of materials - Abstract
Abstract: Porous hydroxyapatite structures were manufactured via a novel preceramic paper process. Preceramic paper sheets were produced from aqueous suspensions loaded with different contents of pulp fiber and HA filler. Pressure loading was applied in order to increase the packing density in the paper sheets. The paper sheets were sintered at 1250°C for 1h. The porous ceramic specimens were characterized for density, porosity, microstructure and mechanical properties. A pronounced volumetric shrinkage was observed, but no surface flaws or inhomogeneous areas were detected. The mechanical strength using the ball on three balls test (B3B test) and elastic modulus of sintered specimens vary between 18 and 28MPa and 0.65–1.53GPa, respectively. [Copyright &y& Elsevier]
- Published
- 2013
- Full Text
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50. Highly porous magnetite/graphene nanocomposites for a solid-state electrochemiluminescence sensor on paper-based chips.
- Author
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Xu, Yuanhong, Lv, Zhaozi, Xia, Yong, Han, Yanchao, Lou, Baohua, and Wang, Erkang
- Subjects
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NANOCOMPOSITE materials , *MAGNETITE , *POROUS materials , *GRAPHENE , *ELECTROCHEMILUMINESCENCE , *DETECTORS - Abstract
Graphene-nanosheet-based highly porous magnetite nanocomposites (GN-HPMNs) have been prepared using a simple solvothermal method and used as an immobilization matrix for the fabrication of a solid-state electrochemiluminescence (ECL) sensor on paper-based chips. Highly porous FeO nanocrystal clusters were coated with acrylate and wrapped tightly on the skeleton of graphene nanosheets. The structures and sizes of the GN-HPMNs could be tuned by varying the proportions of the solvents ethylene glycol and diethylene glycol. Then, the relatively highly porous ones with an average diameter of about 65 nm were combined with Nafion to form composite films on an electrode surface for immobilization of Ru(bpy) (bpy is 2,2′-bipyridine). Because of their porosity, negatively charged surface, and cooperative characteristics of magnetic nanomaterials and graphene, under an external magnetic field, the GN-HPMNs ensured effective immobilization, excellent electron transfer, and long-term stability of Ru(bpy) in the composite film. The sensor developed exhibited excellent reproducibility with a relative standard deviation of 0.65 % for 30 continuous cycles. It was found to be much more favorable for detecting compounds containing tertiary amino groups and DNAs with guanine and adenine. A detection limit (signal-to-noise ratio of 3) of 5.0 nM was obtained for tripropylamine. As an application example, 0.5 nM single-nucleotide mismatch could be detected. This was the first attempt to introduce magnetic nanomaterials and an external magnetic field into paper-based chips. The sensor developed has the advantages of high sensitivity, good stability, and wide potential applicability as well as simplicity, low cost, and good disposability. [Figure not available: see fulltext.] [ABSTRACT FROM AUTHOR]
- Published
- 2013
- Full Text
- View/download PDF
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