Fabrication of Tubular Mullite-Alumina Porous Ceramics by Polymer-Aided Extrusion

2005 ◽  
Vol 486-487 ◽  
pp. 333-337
Author(s):  
Yao Ai Hua ◽  
Ke Yang ◽  
Ruo Ding Wang

Mullite-alumina porous ceramics were fabricated by polymer-aided extrusion through using natural kaolin and alumina as starting materials. The physical and chemical properties of porous ceramics were investigated. The results showed that the approach of using kaolin as starting material offers many benefits such as low cost, big processing capacities, low mullitization temperature and unique microstructure. The porous ceramics with high strength, high porosity, narrow pore size distribution, high permeability and good thermal-shock behavior was obtained by modifying preparation conditions.

2015 ◽  
Vol 1120-1121 ◽  
pp. 21-26
Author(s):  
Cai Yun Jia ◽  
Rui Ding ◽  
Jun Cheng Liu ◽  
An Fa Liu ◽  
Dong Xiao Teng

High alumina foam ceramics products with low density, high specific surface area, low thermal conductivity, corrosion resistance and other excellent physical and chemical properties are suitable for chemical, metallurgy and other related fields [1-4]. Alumina foam ceramics that compression strength increased by 200%, was prepared by Rizwan Ahmad through impregnation process using foamed rubber [5]. However foamed rubber was expensive and could be decomposed creating poisonous gases at high temperature. Zhou l z [6] prepared mullite porous ceramics with high strength by gel-casting method. Gel-casting is an effective method for preparation of ceramics products with large size and complicated shape. Fiber reinforced dense ceramics composite materials with excellent performance have been studied widely [7-10], it is also an important issue to adequately investigate the reinforcement of porous ceramics with fiber.


2021 ◽  
Vol 316 ◽  
pp. 51-55
Author(s):  
Tamara I. Shishelova ◽  
Vadim V. Fedchishin ◽  
Mikhail A. Khramovskih

Rapid expansion of technologies poses higher requirements to structural materials and items made of them. Conventional materials are being replaced by composite materials (composites). Different additives enhancing the properties of initial materials are used as reinforcement fibers of composites. Utilization of micro-and nanosize particles for production of present-day materials is paid much attention to. Whiskers are among such materials. These crystals have high strength, high chemical and temperature resistance. But for rational utilization of whickers of different chemical composition in composite materials one should know their physical and chemical properties. Objectives of the paper: to study physical and chemical properties of whiskers in different compounds, their composition and structure; to prove experimentally the feasibility of utilizing whiskers as a reinforcement fiber of composite materials. Object of study: specimens of whiskers of silicon nitride (Si3N4), aluminum oxide (Al2O3), aluminum nitride (AlN), and mullite (Al6Si2O13). Methods of investigation: thermal study of specimens, study of mechanical properties and chemical strength, and IR-spectroscopy. Results of study: specimens of whiskers have been studied and their mechanical properties have been tabulated for comparison. Extensive thermal investigation was followed by deduction of regularities and identification of chemical properties of whiskers. IR-spectra of whiskers have been studied and conclusions on molecular composition and on presence of impurities in some whiskers have been made.


2004 ◽  
pp. 79-90
Author(s):  
Vesna Vratusa

Efficient nursery production of woody plants, as well as the level of their successful application in urban green spaces, greatly depends upon properties of substrates in which these individuals grow, develop and endure. Furthermore, quality of substrate does not only affect the quality of future product (plant individual or green space), but distinctly determines its price. This element, extremely significant for all countries in transition, thus Serbia as well, commands finding ways of making qualitative, but least expensive substrate. The most logical solution is to use mixtures/substrates of precisely defined properties, composed of domestic components. Results presented in this paper imply that it is possible to create precisely such standard mixtures from domestic resources at relatively low cost, adjusted to needs of particular species, which would ultimately lead to successful, non-expensive nursery production and application of produced stock, both on domestic and foreign markets.


2021 ◽  
Vol 2021 ◽  
pp. 1-10
Author(s):  
Ghazanfar Abbas ◽  
Muhammad Ibrahim ◽  
Ali Ahmad ◽  
Muhammad Azeem ◽  
Kashif Elahi

Natural zeolites are commonly described as macromolecular sieves. Zeolite networks are very trendy chemical networks due to their low-cost implementation. Sodalite network is one of the most studied types of zeolite networks. It helps in the removal of greenhouse gases. To study this rich network, we use an authentic mathematical tool known as M-polynomials of the topological index and show some physical and chemical properties in numerical form, and to understand the structure deeply, we compare different legitimate M-polynomials of topological indices, concluding in the form of graphical comparisons.


2018 ◽  
Vol 930 ◽  
pp. 254-257 ◽  
Author(s):  
Francisca Pereira de Araújo ◽  
Josy Anteveli Osajima ◽  
Mônica Regina Silva de Araujo ◽  
Edson Cavalcanti da Silva Filho ◽  
João Sammy Nery de Souza

Polystyrene is commercial polymer of extensive use in industrial scale due to great physical and chemical properties and low cost. Lifespan of polymer materials can be changed by incorporation of additions to polymeric matrix.The present study aimed to evaluate the influence of crystal violet dye in polystyrene matrices when irradiated by visible radiation. The samples were studied in the form of films, in which solution of crystal violet (5.0x10-4mol.L-1) was added to the PS solution (8% w / w). The films were irradiated with commercial lamp for 150 hours and analyzed with UV-Vis and FTIR. The results showed that the dye degraded at a rate of 16%, however the FTIR analysis revealed that polystyrene did not degrade under the conditions studied, since no formation of carbonyl compounds was observed.


Author(s):  
Hojjat Madadi ◽  
Jasmina Casals-Terré

The outstanding characteristics of polydimethylsiloxane (PDMS) caused its extensive use as base material to manufacture microfluidic devices. PDMS has numerous advantages coming from instinct properties such as its low cost, simple fabrication procedure, and robust nature that make it a compatible material in many applications such as biological and biomedical engineering. In spite of favorable physical and chemical properties, hydrophobic surface of PDMS is sometimes debatable. Because of PDMS is highly hydrophobic, pumping aqueous solution through microchannels using only capillary forces might be difficult. Although many surface treatments methods have been proposed to modify and increase the hydrophilicity of PDMS [Oxygen plasma [1], UV-radiation [2], Silanization and Chemical vapour deposition [3],…], the use of surfactants is the most effective and easiest method to overcome the hydrophobicity compared to more complex protocols which require expensive facilities [4,5]. The hydrophilic behavior of surfactant-added PDMS and especially its biocompatibility has allowed many microfluidic bio-applications such as separation of biomolecules [6,7], blood cell separation [8] and cell-based assay [9,10]. This paper discusses about the efficiency of adding different surfactants on the wettability of PDMS.


2014 ◽  
Vol 10 (2) ◽  
Author(s):  
Erwin Rommel ◽  
Yunan Rusdianto

Erwin Rommel1 & Yunan Rusdianto2Jurusan Teknik Sipil Fakultas Teknik Universitas Muhammadiyah MalangAlamat Korespondensi :Jalan Raya Tlogomas 246 Malang 65144email : [email protected] HP 08123314432ABSTRACTThe use of fly-ash as cementitious will be made to utilize physical and chemical properties offly-ash that has a dominan of silica and good of modulus fines. The use of steam curing will be donein this study which can speed up the cycle of making concrete. This is advantageous in the productionof precast concrete and velocity field construction.The research was conducted by making concrete cube 15x15x15 cm for 80 pieces and thentested the compressive strength and absorption of concrete. Achieve the quality of concrete madewith the provision of K600 with giving the fly-ash respectively 7.5%, 15% and 30% by weight ofcement.The results of the research obtained by the use of fly-ash as much as 7.5% as a cementitiousthat was given to the steam curing will provide the initial strength of concrete reached 47% ofcompressive strength at 28 days. While the effect of giving fly-ash in concrete has not seen absorptionsignificantly when compared to concrete without fly-ash.Key word : concrete, fly-ash, steam curing


2020 ◽  
Vol 27 (11) ◽  
pp. 2030001
Author(s):  
ZHANG YANCONG ◽  
DOU LINBO ◽  
MA NING ◽  
WU FUHUA ◽  
NIU JINCHENG

Electrospun technology is a simple and flexible method for preparation of nanofiber materials with unique physical and chemical properties. The nanofiber diameter is adjustable from several nanometers to few microns during the preparation. Electrospun nanofiber materials are easy to be assembled into different shapes of three-dimensional structures. These materials exhibit high porosity and surface area and can simulate the network structures of collagen fibers in a natural extracellular matrix, thereby providing a growth microenvironment for tissue cells. Electrospun nanofibers therefore have extensive application prospects in the biomedicine field, including in aerospace, filtration, biomedical applications, and biotechnology. Nanotechnology has the potential to revolutionize many fields, such as surface microscopy, silicon fabrication, biochemistry, molecular biology, physical chemistry, and computational engineering, while the advent of nanofibers has increased the understanding of nanotechnology among academia, industry, and the general public. This paper mainly introduces the application of nanofiber materials in tissue engineering, drug release, wound dressing, and other biomedicine fields.


Antioxidants ◽  
2021 ◽  
Vol 10 (2) ◽  
pp. 274
Author(s):  
Davide Piccinino ◽  
Eliana Capecchi ◽  
Elisabetta Tomaino ◽  
Sofia Gabellone ◽  
Valeria Gigli ◽  
...  

Green, biocompatible, and biodegradable antioxidants represent a milestone in cosmetic and cosmeceutical applications. Lignin is the most abundant polyphenol in nature, recovered as a low-cost waste from the pulp and paper industry and biorefinery. This polymer is characterized by beneficial physical and chemical properties which are improved at the nanoscale level due to the emergence of antioxidant and UV shielding activities. Here we review the use of lignin nanoparticles in cosmetic and cosmeceutical applications, focusing on sunscreen and antiaging formulations. Advances in the technology for the preparation of lignin nanoparticles are described highlighting structure activity relationships.


RSC Advances ◽  
2022 ◽  
Vol 12 (3) ◽  
pp. 1433-1450
Author(s):  
Heja Ibrahim Adil ◽  
Mohammad R. Thalji ◽  
Suhad A. Yasin ◽  
Ibtisam A. Saeed ◽  
Mohammed A. Assiri ◽  
...  

Metal–organic frameworks (MOFs) are promising and effective materials for removing heavy metal ions from contaminated water owing to their high porosity, remarkable physical and chemical properties, and high specific surface area.


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