818 research outputs found
Effect of Nanocellulose Types on Microporous Acrylic Acid/Sodium Alginate Super Absorbent Polymers
No full textThe aim of this study was to investigate the effect of different types of nanocellulose, i.e., cellulose nanocrystal (CNC), cellulose nanofiber (CNF) and bacterial nanocellulose (BNC), and also different drying methods (oven-drying and freeze-drying) on the properties of acrylic acid (AA)/sodium alginate (SA) super absorbent polymers (SAPs). In addition, the presence of ammonium per sulfate as an initiator and N-N methylene-bis-acrylamide as a cross-linker were considered. Synthesized SAPs were characterized by Fourier transform infrared (FTIR) spectroscopy and scanning electron microscopy (SEM). The absorption and rheological properties (i.e., storage modulus and loss modulus) were also investigated. The results of FTIR spectroscopy demonstrated several types of interactions, such as hydrogen and esterification, between SA, AA and nanocellulose. SEM analysis revealed a microporous structure in the SAPs. All SAPs had a centrifuge retention capacity (CRC)/free swelling capacity (FSC) ≥ 69%. The absorption behavior showed that the oven-dried SAPs had superior (about 2×) CRC and FRC in different aqueous media compared to the freeze-dried counterparts. The freeze-dried SAPs showed increased rheological properties in comparison to the oven-dried ones, with SAPs containing BNC and CNC having the highest rheological properties, respectively. Overall, it can be concluded that oven-dried SAPs containing CNC had better absorption properties than the other ones tested in this study
Interpenetrating and semi-interpenetrating network superabsorbent hydrogels based on sodium alginate and cellulose nanocrystals: A biodegradable and high-performance solution for adult incontinence pads
No full textSuperabsorbent hydrogels (SAHs) are essential in various applications, including hygienic products like adult incontinence pads. However, synthetic-based super absorbent polymers (SAPs) dominate the market despite being non-biodegradable. Alternatively, bio-based hydrogels, such as sodium alginate (SA)-based hydrogels, offer biodegradable alternatives. In this study, we aimed to enhance the practical applied properties of SA-based hydrogels by grafting SA with acrylic acid (AA) and incorporating cellulose nanocrystals (CNCs). Specifically, we investigated the potential of interpenetrating network (IPN) and semi-interpenetrating network (S-IPN) hydrogels as absorbent materials in adult incontinence pads. The fabricated SAHs were characterized by Fourier transform infrared (FT-IR) spectroscopy and scanning electron microscopy (SEM). They were also evaluated for absorption and rheological properties. The results showed that in IPN/SAHs, the addition of CNCs decreased pore sizes, while in S-IPN/SAHs, CNC incorporation increased pore sizes. The S-IPN/SAHs exhibited a significantly higher free swelling capacity (FSC) with CNCs loading, reaching 142.29 g/g in 0.9 % NaCl solution and 817.4 g/g in distilled water. On the other hand, IPN/SAHs showed a higher storage modulus and lower loss modulus compared to S-IPN/SAHs. Notably, the superior samples from this study showed a 33 % reduction in SAP consumption compared to commercial SAPs, making them more cost-effective for adult incontinence pad manufacturers. Overall, our research demonstrates the potential of interpenetrating and semi-interpenetrating network superabsorbent hydrogels as high-performance absorbent materials. The results offer improved absorbency and cost savings for producers of adult incontinence pads, and bio-based hydrogels like SA-based hydrogels are promising biodegradable alternatives to synthetic-based SAPs
Recent developments in nanocellulose-based aerogels as air filters: A review
No full textToday, one of the world's critical environmental issues is air pollution, which is the most important parameter threatening human health and the environment. Synthetic polymers are widely used in industrial air filter production; however, they are incompatible with the environment due to their secondary pollution. Using renewable materials to manufacture air filters is not only environmentally friendly but also essential. Recently, a new generation of biopolymers called cellulose nanofiber (CNF)-based hydrogels have been proposed, with three dimensional (3D) nanofiber networks and unique physical and mechanical properties. CNFs have become a hot research topic for application as air filter materials because they can compete with synthetic nanofibers due to their advantages, such as abundant, renewable, nontoxic, high specific surface area, high reactivity, flexibility, low cost, low density, and network structure formation. The main focus of the current review is the recent progress in the preparation and employment of nanocellulose materials, especially CNF-based hydrogels, to absorb PM and CO2. This study summarizes the preparation methods, modification strategies, fabrications, and further applications of CNF-based aerogels as air filters. Lastly, challenges in the fabrication of CNFs, and trends for future developments are presented
Application of Analog Adaptive Filters for Dynamic Sensor Compensation
No full textThis paper investigates the application of analog adaptive techniques to the area of dynamic sensor compensation, of which there is little reported work in the literature. The case is illustrated by showing how the response of a load cell can be improved to speed up the process of measurement. The load cell is a sensor with an oscillatory output in which the measurand contributes to the response parameters. Thus, a compensation filter needs to track variation in measurand whereas a simple, fixed filter is only valid at one specific load value. To facilitate this investigation, computer models for the load cell and the adaptive compensation filter have been developed. To allow a practical implementation of the adaptive techniques, a novel piecewise linearization technique is proposed in order to vary a floating voltage-controlled resistor in a linear manner over a wide range. Simulation and practical results are presented, thus demonstrating the effectiveness of the proposed techniques
Functionalized cellulose nanocrystals for enhanced wood protection: Synthesis, characterization, and performance
No full textThis study developed eco-friendly protective materials for wood preservation, focusing on enhancing fungal decay resistance, insect damage prevention, and improving physical and mechanical properties. The research examined the penetration of cellulose nanocrystals (CNCs) and their functionalized compounds into wood tissue, evaluating their impact on poplar wood. Methodology included optimizing CNC production through acid hydrolysis, testing various temperature and time combinations. CNCs were then functionalized with Poly(dimethylsiloxane)-bis(3-aminopropyl) terminated (PDMS-NH), copper hydroxide, zinc oxide, and silver nanoparticles. Characterization techniques such as AFM, TEM, ESEM, XRD, FTIR, and μ-Raman spectroscopy analyzed CNCs and their derivatives. Wood samples were impregnated with CNCs and functionalized CNCs using pressure and vacuum treatments, then tested for weight gain, durability against white rot (Trametes versicolor) and brown rot (Coniophora puteana) fungi, resistance to insect attack (Trichoferus holosericeus), leaching resistance, and mechanical properties. Key findings included successful optimization of CNC production and functionalization, improved resistance against decay fungi (especially with CNC3/Cu treatment), elevating durability classification from "non-durable" to "low durability". However, treatments showed limited effectiveness against insect infestation. Leaching resistance varied among treatments, with CNC3/PDMS-NH performing best. Mechanical properties, particularly modulus of elasticity, improved significantly with CNC3 impregnation, especially in less degraded wood samples. The study contributes to eco-friendly wood protection systems development, demonstrating functionalized CNCs' potential to enhance wood durability and mechanical properties. Further research is needed to improve insect resistance and optimize the leaching performance of CNC-based treatments, paving the way for more sustainable wood preservation methods
Branding the 'Beur' Author Minority Writing and the Media in France
No full textThis book reconsiders authorship by the descendants of North African immigrants to France by consulting how these authors' novels have been discussed and promoted in the national audio-visual media.Cover -- Contents -- Acknowledgements -- List of Illustrations -- 1. Authorship at a Crossroads -- 2. Mehdi Charef and the Invention of Beur Writing -- 3. Competing Visions of Minority Authorship -- 4. Eyewitness Narratives and the Creation of the Beurette -- 5. Rachid Djaïdani and the Shift from Beur to Banlieue Writing -- 6. Revising the Beurette Label -- 7. Sabri Louatah and the Collectif Qui Fait la France? -- Works Cited -- IndexThis book reconsiders authorship by the descendants of North African immigrants to France by consulting how these authors' novels have been discussed and promoted in the national audio-visual media.Description based on publisher supplied metadata and other sources.Electronic reproduction. Ann Arbor, Michigan : ProQuest Ebook Central, YYYY. Available via World Wide Web. Access may be limited to ProQuest Ebook Central affiliated libraries
A new, 3D overlapping-sphere model of cell adhesion:
No full textCell adhesion refers to the ability of cells to make enduring and dynamic attachments to extracellular surfaces and to each other; rightly so it is a focal point of current biological research. I have designed a computational framework to model cell adhesion using a modified overlapping-sphere model. A core feature of the model is the three-dimensional representation of a cell surface that can interact mechanically with its environment. The generalization of a cell as a sphere gives our model the compactness to enable the simulations of thousands of cells, comparable to the number of cells typically encountered through small scale studies of early development and disease. Specifically, we use this computational framework to model adhesion between cells in a monolayer and a fibrous environment, cell shape change, as well as cell replication. We also include elements of cell orientation, or cell polarity, and touch on some aspects of mechanical feedback. We explore some general aspects of developmental biology as well as cancer in mammary ducts. Although we emphasize epithelial cells, which are cells that form monolayers, we also briefly consider migratory cells. The major results are that (1) Cells in a monolayer, like sheets and tubes, need to be both mobile and well-connected to adapt to mechanically stresses, (2) Cells that are not polarized do not produce a stable monolayer of cells, (3) Extracellular support, like a basement membrane, can minimize the stresses experienced at cell-cell junctions, (4) Mitosis triggered by tension can help maintain a monolayer of cells, (5) Cell shape needs to be incorporated into models to minimize undesirable stresses, (6) Our computational framework is useful to predict behavior of cells subjected to mechanical forces. As this is a new model, results are chiefly qualitative, and suggest future work in collaboration with experimentalists to verify and quantitate our results.M.S.Includes bibliographical references (p. 79-81)by Mehdi Doum
Correction: Synthesis and characterization of a new ZIF-67@MgAl 2 O 4 nanocomposite and its adsorption behaviour
No full textPublisher Copyright: © 2021 The Royal Society of Chemistry.The authors regret that an incorrect affiliation was given for co-author Mehdi Bazarganipour in the original article. The correct affiliations are as shown here. The Royal Society of Chemistry apologises for these errors and any consequent inconvenience to authors and readers
RETHINKING INDUSTRIAL POLICY
No full textDespite the hold of the neoliberal orthodoxy on policy making in developing countries, industrial policy remains important for the promotion of industrial development. However, the context for the design of industrial policy has profoundly changed as a result of new rules governing international trade, the rise of global value chains and marketing networks, and other aspects of globalization. Traditionally, the case for industrial policy has been framed in terms of “market failures” but the paper argues that that is not a sufficient basis. After addressing the traditional points of criticism, an attempt is made to outline the “domains” of industrial policy in the current circumstances, especially for industrially lagging countries. As country contexts differ widely there are no satisfactory blueprints for policy making that countries can readily adopt. As in production decisions, considerable ingenuity and innovation is needed in designing policies. This is all the more necessary as the WTO rules have become increasingly stringent and the rise of international trading networks has created new barriers for young firms to enter the world market. These developments have changed the context but not the importance of policy in industrial development. The paper identifies areas where government intervention is needed and can still make a positive difference.
Higher education in Oregon's prisons: measures of access, equity and excellence in practice
No full textresearch team: Maya Lazaro, Jove Rousseau, Fatima Mehdi, James Conway.Title from PDF cover (viewed on November 3, 2021)."2021 Masters of Public Administration Capstone Research."This archived document is maintained by the State Library of Oregon as part of the Oregon Documents Depository Program. It is for informational purposes and may not be suitable for legal purposes.Includes bibliographical references (pages 30-32).Mode of access: Internet from the Oregon Government Publications Collection.Text in English
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