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Silver-clay nanohybrids based on silver nanoparticles (AgNPs) with montmorillonit (MMT) and milled MMT, shortly AgMMTnano and AgMMTmilled, have been prepared to improve the performance of antibacterial properties of paper. The results obtained by dynamic light scattering indicated the presence of silver particles in the nanometer range, which have a great accumulation tendency. The results of AAS and ICP-AES tests showed that nanosilver amount in the AgMMTmilled was doubled compared to the AgMMTnano, but according to the EDX results, the amount of nanosilver in paper treated with the former was less than in the latter. FE-SEM images showed that the dimensions of deposited nanosilver on the surface of clay were smaller than in case of AgNPs alone. Papers treated with nanohybrids had better antibacterial properties compared to that prepared by naked nanosilver. It was also found that the antibacterial property of papers treated with AgMMTnano were more stable during three-stage tests compared to those with AgMMTmilled. Nanohybrids with Ag conc. more than 15 ppm, especially hybrids with Ag conc. of 50 ppm, result in a significant improvement in antibacterial properties of paper. It can be concluded that silver-clay nanohybrid with a 25-ppm concentration of nanosilver could be the best and most economic antibacterial component. [ABSTRACT FROM AUTHOR]

• Bricks made by bottom ashes, cellulose fibers and clay have been successfully made and tested. • Optimum blends are made of 70% of clay, 25% of bottom ashes and 5% of cellulose fibers. • The so made bricks comply mechanical requirements and are 20% lighter. • Lower thermal conductivity and equal specific heat capacity is achieved. • Toxicity analysis abides by standards in force. The paper and pulp industry (PPI) is permanently searching for new ways of managing its residues due to the increasing pressure of new environmental concerns and policies adopted worldwide. In addition, the manufacturing of construction materials such as fired clay bricks (FCBs) is also facing the transformation of its traditional market, which is asking for new materials with a lower environmental footprint but equal or even better technological properties. In considering the large mass flows related to both the PPI and FCB industries, several researchers have pointed out the feasibility of replacing clay by residues produced by PPI. However, these approaches have always considered the replacement of a single residue rather than the addition of several new ones. Conversely, by using both residues at once, the overall FCB performance is improved and the feasibility of this circular economy approach is eased. For instance, the addition of woody fibres increases thermal resistance but reduces mechanical strength. Conversely, the addition of ashes produced by PPI improved the mechanical strength by reducing the thermal resistance due to the increasing content of fluxing agents which improve the fired clay matrix structure. For this reason, this paper explores the technological properties achieved by replacing clay with both ashes and fibres provided by PPI in an integrated approach. By following industrial procedures, the so made fired clay bricks (with 20% of ash and 5% of fibres) meet the standard and show approx. 20% less thermal conductivity, with the same thermal capacity and a density reduction of more than 15%. [ABSTRACT FROM AUTHOR]

In this paper, a brief review on reversible dielectric nonlinearity (RDN) was presented and the mechanism of tunability for ferroelectric ceramics was discussed in several different scale levels, such as atomic level (intrinsic nonlinearity described by ferroelectric thermodynamic theory), nano-meter scale (polar nano-region response), submicron scale (ferroelectric domain and domain wall motion), micron scale (polycrystalline structure of ceramics and surface layer) and macroscopic scale (field induced phase transition). It suggests that RDN is a multi-scale phenomenon and is temperature and frequency-sensitive. The halving field E0 in Roberts' Equation may be a good attempt for the quantitating of RDN. The stability of RDN in paraelectric phase is also mentioned. [ABSTRACT FROM AUTHOR]

The article focuses on a study which described the production of a portable biofilter unit for the removal of odor and colors from wastewaters. Paper pulp and montmorillonite clay were used as packing materials for the fabrication of the biofilter. These reduced the turbidity of the different effluents studied. They also effectively removed the color of the effluent and produced an odorless effluent.

Clay particles added to fibers are not easily retained in the forming sheet so the mechanical properties of paper suffer. Modified starches and polyacrylamide (PAM) are used as retention aids for clay and strengthening agents. Modified starch is a better strengthening agent and retention aid than is polyacrylamide. The high retention of clay can be obtained by using modified starch and PAM. Heated kaolin at 800°C is retained better than unheated kaolin. [ABSTRACT FROM AUTHOR]

Abstract: The need for kaolin pigments by the paper industry with controlled optical and physical properties have significantly changed the type of filler and coating clays available to the paper industry. Processing equipment now used in the production of kaolin products is much more sophisticated and controllable than in the past. Better understanding of the mineralogy and the physical and chemical properties of kaolins, in addition to improved processing techniques, has allowed the kaolin processors to produce engineered or tailored grades that meet particular needs of the user. Particle size and shape, brightness, gloss, opacity, and viscosity can be altered and controlled to meet specific requirements of the paper coater. Examples of several types of engineered products available for use by the paper industry are discussed. [Copyright &y& Elsevier]

In accordance with global estimations, approx. 15 million tons of residues are yearly generated from paper and pulp industry, which are traditionally used as biofuels or just disposed in landfills. However, residues composition and laws in force urge producers to search for new waste management strategies. From another point of view, the construction industry uses more than 33% of total natural resources, worldwide which has led several governments to limit the use of natural raw materials for building. In particular, fired brick industry produces yearly approx. 1600 billion bricks which represents millions of tons of natural resources consumption. Therefore, the goal is to contribute to reduce the amount of used clay. Thus, this paper explores the mineral and technological properties of brick made by using different percentages of paper pulp residues and fired at 900 °C. Results indicate that by increasing the replacement ratio, blend requires larger amounts of water which leads to a proportional increasing of shrinkage during drying. In spite of mineral transformations are not influenced by paper pulp residue, the porosity is linearly increased which leads to reduce compressive strength and thermal conductivity up to 30% for 20% of replacement ratio, in both cases. Thus, it is concluded that series made by replacing up to 10% show compressive strength above 5 MPa, water absorption beyond 20% and toxicity indexes meet the mandatory requirements. [ABSTRACT FROM AUTHOR]

The article presents the case of three sisters who practise pica. Their mother has practised pica during her first three pregnancies. Pica is an abnormal desire to eat inappropriate materials like clay, cement and paper. Pica is also known as a cultural activity which happens in many parts of the world. It cites several reasons for the practice of pica, such as for the relief of stomach discomfort .

The article discusses on the ways of the mentally retarded children on expressing themselves. The best way to express one's feelings is through art forms. In assisting a child expressing himself, the author suggests that it is much better to leave him alone with a piece of paper, a pencil, clay, wood, paper mache and other art materials. It is also suggested to expose the child to many kinds of art materials.