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Sample records for calcium composite material

  1. Calcium phosphate-based ceramic and composite materials for medicine

    International Nuclear Information System (INIS)

    The topical problems in chemistry and technology of materials based on calcium phosphates aimed at both the replacement of damaged bone tissue and its regeneration are discussed. Specific features of the synthesis of nanocrystalline powders and the fabrication of ceramic implants are described. Advances in the development of porous scaffolds from resorbable and osteoconductive calcium phosphates and of hybrid composites that form the basis of bone tissue engineering are considered.

  2. Effects of the methyltrimethoxysilane coupling agent on phenolic and miscanthus composites containing calcium sulfite scrubber material

    Science.gov (United States)

    Jones, Sean

    The purpose of this research is to test the effects of methyltrimethoxysilane coupling agent on composite material containing calcium sulfite obtained from the Southern Illinois Power Co-operative. This scrubber material and the miscanthus plant are of interest due to their use in coal burning power plants to reduce toxic emission. When calcium sulfate is passed through coal fire gas emissions it absorbs mercury and sulfur. In these composites it is used as filler to reduce cost. Miscanthus is a source of both cellulose reinforcement and some natural resin. This plant has low care requirements, little mineral content, useful energy return, and positive environmental effects. Under investigation is whether a post-cure procedure or a silane coupling agent will positively impact the composite. Hot pressing alone may not be enough to fully cure the phenolic. It is hoped that the silane will increase the strength characteristics of the composite by enhancing adhesion between the calcium sulfite and phenolic resin. Possible effects on the miscanthus by the silane will also be tested. Phenolic is being utilized because of its recycling and biodegradable properties along with cost effectiveness in mass production. Composite mechanical performance was measured through 3-point bending to measure flexural strength and strain at breakage. A dynamic mechanical analyzer (DMA) was used to find thermomechanical properties. The post-cure was found to be effective, particularly on the final composite containing silane. When methyltrimethoxysilane was added to the miscanthus prior to fabrication, it was found to reduce flexural strength and density. However the addition of methyltrimethoxysilane to the calcium sulfite altered thermo-mechanical properties to a state more like pure phenolic, with added flexibility and thermal stability.

  3. Integration of calcium and chemical looping combustion using composite CaO/CuO-based materials.

    Science.gov (United States)

    Manovic, Vasilije; Anthony, Edward J

    2011-12-15

    Calcium looping cycles (CaL) and chemical looping combustion (CLC) are two new, developing technologies for reduction of CO(2) emissions from plants using fossil fuels for energy production, which are being intensively examined. Calcium looping is a two-stage process, which includes oxy-fuel combustion for sorbent regeneration, i.e., generation of a concentrated CO(2) stream. This paper discuss the development of composite materials which can use copper(II)-oxide (CuO) as an oxygen carrier to provide oxygen for the sorbent regeneration stage of calcium looping. In other words, the work presented here involves integration of calcium looping and chemical looping into a new class of postcombustion CO(2) capture processes designated as integrated CaL and CLC (CaL-CLC or Ca-Cu looping cycles) using composite pellets containing lime (CaO) and CuO together with the addition of calcium aluminate cement as a binder. Their activity was tested in a thermogravimetric analyzer (TGA) during calcination/reduction/oxidation/carbonation cycles. The calcination/reduction typically was performed in methane (CH(4)), and the oxidation/carbonation stage was carried out using a gas mixture containing both CO(2) and O(2). It was confirmed that the material synthesized is suitable for the proposed cycles; with the very favorable finding that reduction/oxidation of the oxygen carrier is complete. Various schemes for the Ca-Cu looping process have been explored here that would be compatible with these new composite materials, along with some different possibilities for flow directions among carbonator, calciner, and air reactor. PMID:22022778

  4. A new biphasic osteoinductive calcium composite material with a negative Zeta potential for bone augmentation

    Directory of Open Access Journals (Sweden)

    Maciejewski Oliver

    2009-06-01

    Full Text Available Abstract The aim of the present study was to analyze the osteogenic potential of a biphasic calcium composite material (BCC with a negative surface charge for maxillary sinus floor augmentation. In a 61 year old patient, the BCC material was used in a bilateral sinus floor augmentation procedure. Six months postoperative, a bone sample was taken from the augmented regions before two titanium implants were inserted at each side. We analyzed bone neoformation by histology, bone density by computed tomography, and measured the activity of voltage-activated calcium currents of osteoblasts and surface charge effects. Control orthopantomograms were carried out five months after implant insertion. The BCC was biocompatible and replaced by new mineralized bone after being resorbed completely. The material demonstrated a negative surface charge (negative Zeta potential which was found to be favorable for bone regeneration and osseointegration of dental implants.

  5. Calcium phosphate/microgel composites for 3D powderbed printing of ceramic materials.

    Science.gov (United States)

    Birkholz, Mandy-Nicole; Agrawal, Garima; Bergmann, Christian; Schröder, Ricarda; Lechner, Sebastian J; Pich, Andrij; Fischer, Horst

    2016-06-01

    Composites of microgels and calcium phosphates are promising as drug delivery systems and basic components for bone substitute implants. In this study, we synthesized novel composite materials consisting of pure β-tricalcium phosphate and stimuli-responsive poly(N-vinylcaprolactam-co-acetoacetoxyethyl methacrylate-co-vinylimidazole) microgels. The chemical composition, thermal properties and morphology for obtained composites were extensively characterized by Fourier transform infrared, X-ray photoelectron spectroscopy, IGAsorp moisture sorption analyzer, thermogravimetric analysis, granulometric analysis, ESEM, energy dispersive X-ray spectroscopy and TEM. Mechanical properties of the composites were evaluated by ball-on-three-balls test to determine the biaxial strength. Furthermore, initial 3D powderbed-based printing tests were conducted with spray-dried composites and diluted 2-propanol as a binder to evaluate a new binding concept for β-tricalcium phosphate-based granulates. The printed ceramic bodies were characterized before and after a sintering step by ESEM. The hypothesis that the microgels act as polymer adhesive agents by efficient chemical interactions with the β-tricalcium phosphate particles was confirmed. The obtained composites can be used for the development of new scaffolds. PMID:25870955

  6. Mechanical and microstructure of reinforced hydroxyapatite/calcium silicate nano-composites materials

    International Nuclear Information System (INIS)

    Highlights: ► Nano sized of HA and CS powders were prepared. ► Mechanical of HACS composites enhanced with content of CS. ► The apatite formation onto the composites is proved. -- Abstract: In this study, the nano sized hydroxyapatite (HA) and calcium silicate (CS) powders prepared by both chemical precipitation and sol–gel methods respectively. Biphasic nano-composites materials containing different ratios of HA and CS were fabricated and assessed using X-ray diffraction (XRD), Fourier transmission infrared reflectance (FT-IR), transmission electron microscopy (TEM) and scanning electron microscopy (SEM) techniques. The effect of variation of ratios between HA and CS on mechanical properties, microstructure and in vitro study was studied. The results proved that the mechanical properties were enhanced with increasing the CS ratio in the composite. In vitro study proved the formation and nucleation of apatite onto composites surfaces which contain low content of CS after one week of immersion. Finally, it is concluded that the HACS composites containing high HA content at the expense of CS content will be promising for bone substitute’s applications, especially in load bearing sites.

  7. Composite material

    Energy Technology Data Exchange (ETDEWEB)

    Hutchens, Stacy A. (Knoxville, TN); Woodward, Jonathan (Solihull, GB); Evans, Barbara R. (Oak Ridge, TN); O' Neill, Hugh M. (Knoxville, TN)

    2012-02-07

    A composite biocompatible hydrogel material includes a porous polymer matrix, the polymer matrix including a plurality of pores and providing a Young's modulus of at least 10 GPa. A calcium comprising salt is disposed in at least some of the pores. The porous polymer matrix can comprise cellulose, including bacterial cellulose. The composite can be used as a bone graft material. A method of tissue repair within the body of animals includes the steps of providing a composite biocompatible hydrogel material including a porous polymer matrix, the polymer matrix including a plurality of pores and providing a Young's modulus of at least 10 GPa, and inserting the hydrogel material into cartilage or bone tissue of an animal, wherein the hydrogel material supports cell colonization in vitro for autologous cell seeding.

  8. Composite material

    Science.gov (United States)

    Hutchens, Stacy A.; Woodward, Jonathan; Evans, Barbara R.; O'Neill, Hugh M.

    2012-02-07

    A composite biocompatible hydrogel material includes a porous polymer matrix, the polymer matrix including a plurality of pores and providing a Young's modulus of at least 10 GPa. A calcium comprising salt is disposed in at least some of the pores. The porous polymer matrix can comprise cellulose, including bacterial cellulose. The composite can be used as a bone graft material. A method of tissue repair within the body of animals includes the steps of providing a composite biocompatible hydrogel material including a porous polymer matrix, the polymer matrix including a plurality of pores and providing a Young's modulus of at least 10 GPa, and inserting the hydrogel material into cartilage or bone tissue of an animal, wherein the hydrogel material supports cell colonization in vitro for autologous cell seeding.

  9. Calcium phosphate composite materials including inorganic powders, BSA or duplex DNA prepared by W/O/W interfacial reaction method

    International Nuclear Information System (INIS)

    We reported before that inorganic reaction occurring at the interface of W/O/W emulsion is advantageous to produce hollow spheres (microcapsules) of inorganic matrices such as silica. This process enables us to include various materials into inorganic matrices directly. Calcium phosphates were also produced from NH4H2PO4 and Ca(OH)2 by this interfacial reaction method. Various biomaterials are directly incorporated into crystalline calcium phosphate matrices, when the biomaterials are added to the inner water phase of the W/O/W emulsion. ZrO2 and Al2O3 powders were effectively encapsulated in calcium phosphates such as hydroxyapatite (HAp). The images of backscattered electron of FE-SEM observations indicated that ZrO2 particles were included in HAp, while they adhered to the surface of HAp in the case of a simple precipitation method. Biomacromolecules such as BSA and duplex DNA were also included in HAp using the inner water phases dissolving them. Fluorescent microscopy observations revealed that biomacromolecules incorporated in HAp localized in some domains of the HAp matrices. Biomacromolecules thus included were scarcely liberated into deionized water, indicating their strong encapsulation in HAp. This general and simple methodology will provide various composite materials of calcium phosphates, which are applicable to regenerative medicine, DDS, GDS and more

  10. In vitro degradation and cell response of calcium carbonate composite ceramic in comparison with other synthetic bone substitute materials

    International Nuclear Information System (INIS)

    The robust calcium carbonate composite ceramics (CC/PG) can be acquired by fast sintering calcium carbonate at a low temperature (650 °C) using a biocompatible, degradable phosphate-based glass (PG) as sintering agent. In the present study, the in vitro degradation and cell response of CC/PG were assessed and compared with 4 synthetic bone substitute materials, calcium carbonate ceramic (CC), PG, hydroxyapatite (HA) and β-tricalcium phosphate (β-TCP) ceramics. The degradation rates in decreasing order were as follows: PG, CC, CC/PG, β-TCP, and HA. The proliferation of rat bone mesenchymal stem cells (rMSCs) cultured on the CC/PG was comparable with that on CC and PG, but inferior to HA and β-TCP. The alkaline phosphatase (ALP) activity of rMSCs on CC/PG was lower than PG, comparable with β-TCP, but higher than HA. The rMSCs on CC/PG and PG had enhanced gene expression in specific osteogenic markers, respectively. Compared to HA and β-TCP, the rMSCs on the CC/PG expressed relatively lower level of collagen I and runt-related transcription factor 2, but showed more considerable expression of osteopontin. Although CC, PG, HA, and β-TCP possessed impressive performances in some specific aspects, they faced extant intrinsic drawbacks in either degradation rate or mechanical strength. Based on considerable compressive strength, moderate degradation rate, good cell response, and being free of obvious shortcoming, the CC/PG is promising as another choice for bone substitute materials. - Highlights: • A calcium carbonate composite ceramic (CC/PG) was acquired. • The in vitro degradation and cell response of CC/PG were compared to 4 materials. • The CC/PG showed moderate degradation rate. • The CC/PG exhibited good cell response. • The CC/PG was free of obvious drawback compared to other materials

  11. In vitro degradation and cell response of calcium carbonate composite ceramic in comparison with other synthetic bone substitute materials

    Energy Technology Data Exchange (ETDEWEB)

    He, Fupo [Department of Biomedical Engineering, School of Basic Sciences, Guangzhou Medical University, Guangzhou 510182 (China); Zhang, Jing [School of Materials Science and Engineering, South China University of Technology, Guangzhou 510641 (China); Yang, Fanwen; Zhu, Jixiang; Tian, Xiumei [Department of Biomedical Engineering, School of Basic Sciences, Guangzhou Medical University, Guangzhou 510182 (China); Chen, Xiaoming, E-mail: xmchenw@126.com [Department of Biomedical Engineering, School of Basic Sciences, Guangzhou Medical University, Guangzhou 510182 (China)

    2015-05-01

    The robust calcium carbonate composite ceramics (CC/PG) can be acquired by fast sintering calcium carbonate at a low temperature (650 °C) using a biocompatible, degradable phosphate-based glass (PG) as sintering agent. In the present study, the in vitro degradation and cell response of CC/PG were assessed and compared with 4 synthetic bone substitute materials, calcium carbonate ceramic (CC), PG, hydroxyapatite (HA) and β-tricalcium phosphate (β-TCP) ceramics. The degradation rates in decreasing order were as follows: PG, CC, CC/PG, β-TCP, and HA. The proliferation of rat bone mesenchymal stem cells (rMSCs) cultured on the CC/PG was comparable with that on CC and PG, but inferior to HA and β-TCP. The alkaline phosphatase (ALP) activity of rMSCs on CC/PG was lower than PG, comparable with β-TCP, but higher than HA. The rMSCs on CC/PG and PG had enhanced gene expression in specific osteogenic markers, respectively. Compared to HA and β-TCP, the rMSCs on the CC/PG expressed relatively lower level of collagen I and runt-related transcription factor 2, but showed more considerable expression of osteopontin. Although CC, PG, HA, and β-TCP possessed impressive performances in some specific aspects, they faced extant intrinsic drawbacks in either degradation rate or mechanical strength. Based on considerable compressive strength, moderate degradation rate, good cell response, and being free of obvious shortcoming, the CC/PG is promising as another choice for bone substitute materials. - Highlights: • A calcium carbonate composite ceramic (CC/PG) was acquired. • The in vitro degradation and cell response of CC/PG were compared to 4 materials. • The CC/PG showed moderate degradation rate. • The CC/PG exhibited good cell response. • The CC/PG was free of obvious drawback compared to other materials.

  12. Application of Calcium Phosphate Materials in Dentistry

    Directory of Open Access Journals (Sweden)

    Jabr S. Al-Sanabani

    2013-01-01

    Full Text Available Calcium phosphate materials are similar to bone in composition and in having bioactive and osteoconductive properties. Calcium phosphate materials in different forms, as cements, composites, and coatings, are used in many medical and dental applications. This paper reviews the applications of these materials in dentistry. It presents a brief history, dental applications, and methods for improving their mechanical properties. Notable research is highlighted regarding (1 application of calcium phosphate into various fields in dentistry; (2 improving mechanical properties of calcium phosphate; (3 biomimetic process and functionally graded materials. This paper deals with most common types of the calcium phosphate materials such as hydroxyapatite and tricalcium phosphate which are currently used in dental and medical fields.

  13. The preparation and performance of calcium carbide-derived carbon/polyaniline composite electrode material for supercapacitors

    Energy Technology Data Exchange (ETDEWEB)

    Zheng, Liping; Wang, Xianyou; Li, Na; An, Hongfang; Chen, Huajie [School of Chemistry, Key Laboratory of Environmentally Friendly Chemistry and Applications of Minister of Education, Xiangtan University, Hunan 411105 (China); Wang, Ying; Guo, Jia [School of Chemical Engineering and Pharmacy, Wuhan Institute of Technology, Hubei 430073 (China)

    2010-03-15

    Calcium carbide (CaC{sub 2})-derived carbon (CCDC)/polyaniline (PANI) composite materials are prepared by in situ chemical oxidation polymerization of an aniline solution containing well-dispersed CCDC. The structure and morphology of CCDC/PANI composite are characterized by Fourier infrared spectroscopy (FTIR), scanning electron microscope (SEM), transmission electron microscopy (TEM) and N{sub 2} sorption isotherms. It has been found that PANI was uniformly deposited on the surface and the inner pores of CCDC. The supercapacitive behaviors of the CCDC/PANI composite materials are investigated with cyclic voltammetry (CV), galvanostatic charge/discharge and cycle life measurements. The results show that the CCDC/PANI composite electrodes have higher specific capacitances than the as grown CCDC electrodes and higher stability than the conducting polymers. The capacitance of CCDC/PANI composite electrode is as high as 713.4 F g{sup -1} measured by cyclic voltammetry at 1 mV s{sup -1}. Besides, the capacitance retention of coin supercapacitor remained 80.1% after 1000 cycles. (author)

  14. The preparation and performance of calcium carbide-derived carbon/polyaniline composite electrode material for supercapacitors

    Science.gov (United States)

    Zheng, Liping; Wang, Ying; Wang, Xianyou; Li, Na; An, Hongfang; Chen, Huajie; Guo, Jia

    Calcium carbide (CaC 2)-derived carbon (CCDC)/polyaniline (PANI) composite materials are prepared by in situ chemical oxidation polymerization of an aniline solution containing well-dispersed CCDC. The structure and morphology of CCDC/PANI composite are characterized by Fourier infrared spectroscopy (FTIR), scanning electron microscope (SEM), transmission electron microscopy (TEM) and N 2 sorption isotherms. It has been found that PANI was uniformly deposited on the surface and the inner pores of CCDC. The supercapacitive behaviors of the CCDC/PANI composite materials are investigated with cyclic voltammetry (CV), galvanostatic charge/discharge and cycle life measurements. The results show that the CCDC/PANI composite electrodes have higher specific capacitances than the as grown CCDC electrodes and higher stability than the conducting polymers. The capacitance of CCDC/PANI composite electrode is as high as 713.4 F g -1 measured by cyclic voltammetry at 1 mV s -1. Besides, the capacitance retention of coin supercapacitor remained 80.1% after 1000 cycles.

  15. Composite Materials

    DEFF Research Database (Denmark)

    Nielsen, Lauge Fuglsang

    This book deals with the mechanical and physical behavior of composites as influenced by composite geometry. "Composite Materials" provides a comprehensive introduction for researchers and students to modern composite materials research with a special emphasis on the significance of phase geometry....... The book enables the reader to a better understanding of the behavior of natural composites, improvement of such materials, and design of new materials with prescribed properties. A number of examples are presented: Special composite properties considered are stiffness, shrinkage, hygro...

  16. Silicon, iron and titanium doped calcium phosphate-based glass reinforced biodegradable polyester composites as bone analogous materials

    Science.gov (United States)

    Shah Mohammadi, Maziar

    Bone defects resulting from disease or traumatic injury is a major health care problem worldwide. Tissue engineering offers an alternative approach to repair and regenerate bone through the use of a cell-scaffold construct. The scaffold should be biodegradable, biocompatible, porous with an open pore structure, and should be able to withstand the applied forces. Phosphate-based glasses (PGs) may be used as reinforcing agents in degradable composites since their degradation can be predicted and controlled through their chemistry. This doctoral dissertation describes the development and evaluation of PGs reinforced biodegradable polyesters for intended applications in bone augmentation and regeneration. This research was divided into three main objectives: 1) Investigating the composition dependent properties of novel PG formulations by doping a sodium-free calcium phosphate-based glass with SiO2, Fe2O3, and TiO2. Accordingly, (50P2 O5-40CaO- xSiO2-(10-x)Fe2O3, where x = 10, 5 and 0 mol.%) and (50P2O5-40CaO-xSiO 2-(10-x)TiO2 where x = 10, 7, 5, 3 and 0 mol.%) formulations were developed and characterised. SiO2 incorporation led to increased solubility, ion release, pH reduction, as well as hydrophilicity, surface energy, and surface polarity. In contrast, doping with Fe2O 3 or TiO2 resulted in more durable glasses, and improved cell attachment and viability. It was hypothesised that the presence of SiO 2 in the TiO2-doped formulations could up-regulate the ionic release from the PG leading to higher alkaline phosphatase activity of MC3T3-E1 cells. 2) Incorporating Si, Fe, and Ti doped PGs as fillers, either as particulates (PGPs) or fibres (PGFs), into biodegradable polyesters (polycaprolactone (PCL) and semi-crystalline and amorphous poly(lactic acid) (PLA and PDLLA)) with the aim of developing degradable bone analogous composites. It was found that PG composition and geometry dictated the weight loss, ionic release, and mechanical properties of the composites. It

  17. Amorphous calcium phosphate composites with improved mechanical properties

    OpenAIRE

    O’Donnell, J.N.R.; Antonucci, J.M.; Skrtic, D.

    2006-01-01

    Hybridized zirconium amorphous calcium phosphate (ACP)-filled methacrylate composites make good calcium and phosphate releasing materials for anti-demineralizing/remineralizing applications with low mechanical demands. The objective of this study was to assess the effect of the particle size of the filler on the mechanical properties of these composites. Photo-curable resins were formulated from ethoxylated bisphenol A dimethacrylate, triethylene glycol dimethacrylate, 2-hydroxyethyl methacry...

  18. Mechanical and physical behavior of newly developed functionally graded materials and composites of stainless steel 316L with calcium silicate and hydroxyapatite.

    Science.gov (United States)

    Ataollahi Oshkour, Azim; Pramanik, Sumit; Mehrali, Mehdi; Yau, Yat Huang; Tarlochan, Faris; Abu Osman, Noor Azuan

    2015-09-01

    This study aimed to investigate the structural, physical and mechanical behavior of composites and functionally graded materials (FGMs) made of stainless steel (SS-316L)/hydroxyapatite (HA) and SS-316L/calcium silicate (CS) employing powder metallurgical solid state sintering. The structural analysis using X-ray diffraction showed that the sintering at high temperature led to the reaction between compounds of the SS-316L and HA, while SS-316L and CS remained intact during the sintering process in composites of SS-316L/CS. A dimensional expansion was found in the composites made of 40 and 50 wt% HA. The minimum shrinkage was emerged in 50 wt% CS composite, while the maximum shrinkage was revealed in samples with pure SS-316L, HA and CS. Compressive mechanical properties of SS-316L/HA decreased sharply with increasing of HA content up to 20 wt% and gradually with CS content up to 50 wt% for SS-316L/CS composites. The mechanical properties of the FGM of SS-316L/HA dropped with increase in temperature, while it was improved for the FGM of SS-316L/CS with temperature enhancement. It has been found that the FGMs emerged a better compressive mechanical properties compared to both the composite systems. Therefore, the SS-316L/CS composites and their FGMs have superior compressive mechanical properties to the SS-316L/HA composites and their FGMs and also the newly developed FGMs of SS-316L/CS with improved mechanical and enhanced gradation in physical and structural properties can potentially be utilized in the components with load-bearing application. PMID:26072197

  19. CALCIUM ISOTOPE COMPOSITION OF METEORITES, EARTH, AND MARS

    International Nuclear Information System (INIS)

    The relative abundances of calcium isotopes in the mass range 40-44 were measured in primitive and differentiated meteorites and igneous rocks from Earth and Mars in search of non-mass-dependent variations that could provide clues about early solar system processes. Most bulk samples of planetary materials have calcium isotopic compositions identical with Earth's within the current resolution of about 0.01% in 40Ca/44Ca. Possible exceptions include carbonaceous chondrites, some ordinary chondrites, and two samples of calcium-aluminum-rich inclusions, which have small excesses of 40Ca. The samples with 40Ca excesses are also known to have 50Ti and 135Ba excesses and 142Nd and 144Sm deficits. Collectively these data from refractory elements suggest that the planetary embryos represented by chondrites preserve isotopic heterogeneity that reflects different nucleosynthetic sources. No late admixture from a single nucleosynthetic source can explain all observations. The results are most compatible with variable proportions of material derived from Type II supernovae. The initial calcium isotope compositions of Earth and Mars are indistinguishable and similar to the 40Ca abundance found in some chondrites and all differentiated meteorites studied. It appears that isotopic heterogeneity in calcium was still present at the completion of disk formation but was homogenized during planetary accretion.

  20. Composition and genesis of calcium deposits in atheroma plaques.

    Science.gov (United States)

    Lara, María Jesús; Ros, Eduardo; Sierra, Manuel; Dorronsoro, Carlos; Aguilar, José

    2014-05-01

    The composition of atheromatous plaque determines its progression toward rupture or thrombosis. Although its histopathological structure has been widely studied, little attention has been paid to its structural and chemical composition and even less to its mineral component. Thirty-three atheromatous plaques were obtained by carotid thromboendarterectomy. Three types of materials were observed under polarized light microscopy: apatite crystals in the form of glomeruli (dark with plane polarized illumination and greensh with cross-polarized illumination); fibrous-like cholesterol (uncolored or grayish with plane-polarized illumination); and amorphous organic material as brownish deposits. SEM-EDX analysis showed an abundance of phosphorus and calcium in sufficient quantities to form calcium phosphates, and appreciably reduced levels of sodium. X-ray diffraction results differentiated samples into three groups: group I with predominance of hydroxyapatite-type crystals, group II with crystalline material containing an amorphous component, and group III with wholly amorphous material. The most abundant mineral in atheromatous plaque is hydroxyapatite, on which crystals of cholesterol and lipid nuclei are deposited, stratifying the plaque into layers that reflect the different stages of its formation. The difference in calcium and sodium concentrations between arteries with and without atheromata may indicate an important relationship in the pathophysiological development of calcium deposits. PMID:24134634

  1. Calcium Aluminate based Cement as Dental Restorative Materials

    OpenAIRE

    Kraft, Lars

    2002-01-01

    This thesis presents the results from the development process of a ceramic dental filling material based on calcium aluminate cement. The main focus of the work concerns dimensional changes during setting, hardening and curing and the understanding of the factors controlling the dimensional stability of the system. A range of compositions for research purposes and the composition of Doxadent™ – a dental product launched on the Swedish market in October 2000 – were evaluated. Furthermore hardn...

  2. A Comparative Evaluation of the Mechanical Properties of Two Calcium Phosphate/Collagen Composite Materials and Their Osteogenic Effects on Adipose-Derived Stem Cells

    Directory of Open Access Journals (Sweden)

    Qing Li

    2016-01-01

    Full Text Available Adipose-derived stem cells (ADSCs are ideal seed cells for use in bone tissue engineering and they have many advantages over other stem cells. In this study, two kinds of calcium phosphate/collagen composite scaffolds were prepared and their effects on the proliferation and osteogenic differentiation of ADSCs were investigated. The hydroxyapatite/β-tricalcium phosphate (HA/β-TCP composite scaffolds (HTPSs, which have an additional β-tricalcium phosphate, resulted in better proliferation of ADSCs and showed osteogenesis-promoting effects. Therefore, such composite scaffolds, in combination with ADSCs or on their own, would be promising for use in bone regeneration and potential clinical therapy for bone defects.

  3. A Novel Synthesis Method of Porous Calcium Silicate Hydrate Based on the Calcium Oxide/Polyethylene Glycol Composites

    OpenAIRE

    Wei Guan; Fangying Ji; Yong Cheng; Zhuoyao Fang; Dexin Fang; Peng Yan; Qingkong Chen

    2013-01-01

    This paper proposed a novel method to prepare porous calcium silicate hydrate (CSH) based on the calcium oxide/polyethylene glycol (CaO/PEG2000) composites as the calcium materials. The porosity formation mechanism was revealed via X-ray diffraction (XRD), field-emission scanning electron microscopy (FESEM), Brunauer-Emmett-Teller (BET), and Fourier transformed infrared spectroscopy (FT-IR). The reactivity of silica materials (SiO2) enhanced by increasing pH value. Ca2+ could not sustain rele...

  4. Nano-composite materials

    Science.gov (United States)

    Lee, Se-Hee; Tracy, C. Edwin; Pitts, J. Roland

    2010-05-25

    Nano-composite materials are disclosed. An exemplary method of producing a nano-composite material may comprise co-sputtering a transition metal and a refractory metal in a reactive atmosphere. The method may also comprise co-depositing a transition metal and a refractory metal composite structure on a substrate. The method may further comprise thermally annealing the deposited transition metal and refractory metal composite structure in a reactive atmosphere.

  5. Multifunctional Composite Materials Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Polymeric composite materials that are currently utilized in aircraft structures are susceptible to significant damage from lightning strikes. Enhanced electrical...

  6. An investigation on physical properties of polyethylene composite with bentonite, kaolin and calcium carbonate additives

    OpenAIRE

    Karabeyoğlu, Sencer S.; , Nurşen Öntürk

    2014-01-01

    Bentonite, Kaolin, Calcium carbonate easily obtained in nature as mineral products are widely used in plastics industry for additive materials. In this study, Bentonite, Kaolin, and Calcium carbonate minerals were compounded with polyethylene matrix used in specific rates. Prepared compounds melted in sheet metal molds and cooled down under appropriate conditions. Thus, production of composite material was achieved. Hardness, water absorption, and physical properties of manufactured composite...

  7. Friction Material Composites Materials Perspective

    CERN Document Server

    Sundarkrishnaa, K L

    2012-01-01

    Friction Material Composites is the first of the five volumes which strongly educates and updates engineers and other professionals in braking industries, research and test labs. It explains besides the formulation of design processes and its complete manufacturing input. This book gives an idea of mechanisms of friction and how to control them by designing .The book is  useful for designers  of automotive, rail and aero industries for designing the brake systems effectively with the integration of friction material composite design which is critical. It clearly  emphasizes the driving  safety and how serious designers should  select the design input. The significance of friction material component like brake pad or a liner as an integral part of the brake system of vehicles is explained. AFM pictures at nanolevel illustrate broadly the explanations given.

  8. Mechanical behavior of a composite interface: Calcium-silicate-hydrates

    Energy Technology Data Exchange (ETDEWEB)

    Palkovic, Steven D.; Moeini, Sina; Büyüköztürk, Oral, E-mail: obuyuk@mit.edu [Department of Civil and Environmental Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139 (United States); Yip, Sidney [Department of Nuclear Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139 (United States)

    2015-07-21

    The generalized stacking fault (GSF) is a conceptual procedure historically used to assess shear behavior of defect-free crystalline structures through molecular dynamics or density functional theory simulations. We apply the GSF technique to the spatially and chemically complex quasi-layered structure of calcium-silicate-hydrates (C-S-H), the fundamental nanoscale binder within cementitious materials. A failure plane is enforced to calculate the shear traction-displacement response along a composite interface containing highly confined water molecules, hydroxyl groups, and calcium ions. GSF simulations are compared with affine (homogeneous) shear simulations, which allow strain to localize naturally in response to the local atomic environment. Comparison of strength and deformation behavior for the two loading methods shows the composite interface controls bulk shear deformation. Both models indicate the maximum shear strength of C-S-H exhibits a normal-stress dependency typical of cohesive-frictional materials. These findings suggest the applicability of GSF techniques to inhomogeneous structures and bonding environments, including other layered systems such as biological materials containing organic and inorganic interfaces.

  9. Mechanical behavior of a composite interface: Calcium-silicate-hydrates

    International Nuclear Information System (INIS)

    The generalized stacking fault (GSF) is a conceptual procedure historically used to assess shear behavior of defect-free crystalline structures through molecular dynamics or density functional theory simulations. We apply the GSF technique to the spatially and chemically complex quasi-layered structure of calcium-silicate-hydrates (C-S-H), the fundamental nanoscale binder within cementitious materials. A failure plane is enforced to calculate the shear traction-displacement response along a composite interface containing highly confined water molecules, hydroxyl groups, and calcium ions. GSF simulations are compared with affine (homogeneous) shear simulations, which allow strain to localize naturally in response to the local atomic environment. Comparison of strength and deformation behavior for the two loading methods shows the composite interface controls bulk shear deformation. Both models indicate the maximum shear strength of C-S-H exhibits a normal-stress dependency typical of cohesive-frictional materials. These findings suggest the applicability of GSF techniques to inhomogeneous structures and bonding environments, including other layered systems such as biological materials containing organic and inorganic interfaces

  10. Controlled degradation pattern of hydroxyapatite/calcium carbonate composite microspheres.

    Science.gov (United States)

    Yang, Ning; Zhong, Qiwei; Zhou, Ying; Kundu, Subhas C; Yao, Juming; Cai, Yurong

    2016-06-01

    Hydroxyapatite (HAP) is widely used in clinic due to its good biocompatibility and osteoconductivity except for its slow degradation speed. In the present study, spherical calcium carbonate (CaCO3 ) is fabricated in the presence of silk protein sericin, which is transmuted into HAP microsphere in phosphate solution with the assistance of microwave irradiation. The effect of reaction conditions on the conversion of CaCO3 is investigated including reaction time, chemical composition of phosphate solution, and microwave power to get a series of HAP/CaCO3 composites. The degradation property of the composites is evaluated in vitro. Results show the degradation speed of the composite with higher HAP content is slower. The degradation rate of the composite could be changed effectively by modulating the proportion of HAP and CaCO3 . This work provides a feasible method for the preparation of spherical HAP/CaCO3 composite with controllable degradability. The composite thus obtained may be an ideal material for bone tissue engineering application. Microsc. Res. Tech. 79:518-524, 2016. © 2016 Wiley Periodicals, Inc. PMID:27037606

  11. Superconducting composites materials

    International Nuclear Information System (INIS)

    The new superconductor materials with a high critical current own a large importance as well in the electronic components or in the electrotechnical devices fields. The deposit of such materials with the thick films technology is to be more and more developed in the years to come. Therefore, we tried to realize such thick films screen printed on alumina, and composed mainly of the YBa2Cu3O7-δ material. We first realized a composite material glass/YBa2Cu3O7-δ, by analogy with the classical screen-printed inks where the glass ensures the bonding with the substrate. We thus realized different materials by using some different classes of glass. These materials owned a superconducting transition close to the one of the pure YBa2Cu3O7-δ material. We made a slurry with the most significant composite materials and binders, and screen-printed them on an alumina substrate preliminary or not coated with a diffusion barrier layer. After firing, we studied the thick films adhesion, the alumina/glass/composite material interfaces, and their superconducting properties. 8 refs.; 14 figs.; 9 tabs

  12. Nanostructured composite reinforced material

    Science.gov (United States)

    Seals, Roland D.; Ripley, Edward B.; Ludtka, Gerard M.

    2012-07-31

    A family of materials wherein nanostructures and/or nanotubes are incorporated into a multi-component material arrangement, such as a metallic or ceramic alloy or composite/aggregate, producing a new material or metallic/ceramic alloy. The new material has significantly increased strength, up to several thousands of times normal and perhaps substantially more, as well as significantly decreased weight. The new materials may be manufactured into a component where the nanostructure or nanostructure reinforcement is incorporated into the bulk and/or matrix material, or as a coating where the nanostructure or nanostructure reinforcement is incorporated into the coating or surface of a "normal" substrate material. The nanostructures are incorporated into the material structure either randomly or aligned, within grains, or along or across grain boundaries.

  13. Electrophoretic deposition of calcium silicate-reduced graphene oxide composites on titanium substrate

    DEFF Research Database (Denmark)

    Mehrali, Mehdi; Akhiani, Amir Reza; Talebian, Sepehr;

    2016-01-01

    silicate-reduced graphene oxide (CS-rGO) composites were synthesized, using an in situ hydrothermal method. CS nanowires were uniformly decorated on the rGO, with an appropriate interfacial bonding. The CS-rGO composites behaved like hybrid composites when deposited on a titanium substrate by cathodic......Calcium silicate (CS)/graphene coatings have been used to improve the biological and mechanical fixation of metallic prosthesis. Among the extraordinary features of graphene is its very high mechanical strength, which makes it an attractive nanoreinforcement material for composites. Calcium...

  14. A Novel Synthesis Method of Porous Calcium Silicate Hydrate Based on the Calcium Oxide/Polyethylene Glycol Composites

    Directory of Open Access Journals (Sweden)

    Wei Guan

    2013-01-01

    Full Text Available This paper proposed a novel method to prepare porous calcium silicate hydrate (CSH based on the calcium oxide/polyethylene glycol (CaO/PEG2000 composites as the calcium materials. The porosity formation mechanism was revealed via X-ray diffraction (XRD, field-emission scanning electron microscopy (FESEM, Brunauer-Emmett-Teller (BET, and Fourier transformed infrared spectroscopy (FT-IR. The reactivity of silica materials (SiO2 enhanced by increasing pH value. Ca2+ could not sustain release from CaO/PEG2000 and reacted with caused by silica to form CSH until the hydrothermal temperature reached to 170°C, avoiding the hardly dissolved intermediates formation efficiently. The as-prepared CSH, due to the large specific surface areas, exhibited excellent release capability of Ca2+ and OH−. This porous CSH has potential application in reducing the negative environmental effects of continual natural phosphate resource depletion.

  15. Micromechanics of Composite Materials

    CERN Document Server

    Dvorak, George

    2013-01-01

    This book presents a broad exposition of analytical and numerical methods for modeling composite materials, laminates, polycrystals and other heterogeneous solids, with emphasis on connections between material properties and responses on several length scales, ranging from the nano and microscales to the macroscale. Many new results and methods developed by the author are incorporated into a rich fabric of the subject, which has been explored by several researchers over the last 40 years.   The first  part of the book reviews anisotropic elasticity theory, and then it describes the frequently used procedures and theorems for bounding and estimating overall properties, local fields and energy changes in elastic inhomogeneities, heterogeneous media, fiber composites and functionally graded materials.  Those are caused by mechanical loads and by phase eigenstrains, such as thermal, transformation and inelastic strains, and also by cavities and cracks.    Worked examples show that the eigendeformations may...

  16. Structure-Composition-Property Relationships in Polymeric Amorphous Calcium Phosphate-Based Dental Composites

    Directory of Open Access Journals (Sweden)

    Drago Skrtic

    2009-11-01

    Full Text Available Our studies of amorphous calcium phosphate (ACP-based materials over the last decade have yielded bioactive polymeric composites capable of protecting teeth from demineralization or even regenerating lost tooth mineral. The anti-cariogenic/remineralizing potential of these ACP composites originates from their propensity, when exposed to the oral environment, to release in a sustained manner sufficient levels of mineral-forming calcium and phosphate ions to promote formation of stable apatitic tooth mineral. However, the less than optimal ACP filler/resin matrix cohesion, excessive polymerization shrinkage and water sorption of these experimental materials can adversely affect their physicochemical and mechanical properties, and, ultimately, limit their lifespan. This study demonstrates the effects of chemical structure and composition of the methacrylate monomers used to form the matrix phase of composites on degree of vinyl conversion (DVC and water sorption of both copolymers and composites and the release of mineral ions from the composites. Modification of ACP surface via introducing cations and/or polymers ab initio during filler synthesis failed to yield mechanically improved composites. However, moderate improvement in composite’s mechanical stability without compromising its remineralization potential was achieved by silanization and/or milling of ACP filler. Using ethoxylated bisphenol A dimethacrylate or urethane dimethacrylate as base monomers and adding moderate amounts of hydrophilic 2-hydroxyethyl methacrylate or its isomer ethyl-α-hydroxymethacrylate appears to be a promising route to maximize the remineralizing ability of the filler while maintaining high DVC. Exploration of the structure/composition/property relationships of ACP fillers and polymer matrices is complex but essential for achieving a better understanding of the fundamental mechanisms that govern dissolution/re-precipitation of bioactive ACP fillers, and

  17. Aerogel/polymer composite materials

    Science.gov (United States)

    Williams, Martha K. (Inventor); Smith, Trent M. (Inventor); Fesmire, James E. (Inventor); Roberson, Luke B. (Inventor); Clayton, LaNetra M. (Inventor)

    2010-01-01

    The invention provides new composite materials containing aerogels blended with thermoplastic polymer materials at a weight ratio of aerogel to thermoplastic polymer of less than 20:100. The composite materials have improved thermal insulation ability. The composite materials also have better flexibility and less brittleness at low temperatures than the parent thermoplastic polymer materials.

  18. Composite materials having thiol groups

    International Nuclear Information System (INIS)

    A composite material having thiol groups comprises a rigid support material. The composite material may comprise a deformable gel (eg agarose) having thiol groups retained within the pore structure of a porous rigid support material (e.g. Kieselghur). The particles of composite material are used to prepare a radioactive gold isotope from a mercury 'parent' isotope. (author)

  19. A honeycomb composite of mollusca shell matrix and calcium alginate.

    Science.gov (United States)

    You, Hua-jian; Li, Jin; Zhou, Chan; Liu, Bin; Zhang, Yao-guang

    2016-03-01

    A honeycomb composite is useful to carry cells for application in bone, cartilage, skin, and soft tissue regenerative therapies. To fabricate a composite, and expand the application of mollusca shells as well as improve preparing methods of calcium alginate in tissue engineering research, Anodonta woodiana shell powder was mixed with sodium alginate at varying mass ratios to obtain a gel mixture. The mixture was frozen and treated with dilute hydrochloric acid to generate a shell matrix/calcium alginate composite. Calcium carbonate served as the control. The composite was transplanted subcutaneously into rats. At 7, 14, 42, and 70 days after transplantation, frozen sections were stained with hematoxylin and eosin, followed by DAPI, β-actin, and collagen type-I immunofluorescence staining, and observed using laser confocal microscopy. The composite featured a honeycomb structure. The control and composite samples displayed significantly different mechanical properties. The water absorption rate of the composite and control group were respectively 205-496% and 417-586%. The composite (mass ratio of 5:5) showed good biological safety over a 70-day period; the subcutaneous structure of the samples was maintained and the degradation rate was lower than that of the control samples. Freezing the gel mixture afforded control over chemical reaction rates. Given these results, the composite is a promising honeycomb scaffold for tissue engineering. PMID:26700239

  20. Gel time of calcium acrylate grouting material.

    Science.gov (United States)

    Han, Tong-Chun

    2004-08-01

    Calcium acrylate is a polymerized grout, and can polymerize in an aqueous solution. The polymerization reaction utilizes ammonium persulfate as a catalyst and sodium thiosulfate as the activator. Based on the theory of reaction kinetics, this study on the relation between gel time and concentration of activator and catalyst showed that gel time of calcium acrylate is inversely proportional to activator and catalyst concentration. A formula of gel time is proposed, and an example is provided to verify the proposed formula. PMID:15236477

  1. Nacre-like calcium carbonate controlled by ionic liquid/graphene oxide composite template

    International Nuclear Information System (INIS)

    Nacre-like calcium carbonate nanostructures have been mediated by an ionic liquid (IL)-graphene oxide (GO) composite template. The resultant crystals were characterized by scanning electron microscopy (SEM), Fourier transform infrared (FT-IR) spectroscopy, and X-ray powder diffractometry (XRD). The results showed that either 1-butyl-3-methylimidazolium tetrafluoroborate ([BMIM]BF4) or graphene oxide can act as a soft template for calcium carbonate formation with unusual morphologies. Based on the time-dependent morphology changes of calcium carbonate particles, it is concluded that nacre-like calcium carbonate nanostructures can be formed gradually utilizing [BMIM]BF4/GO composite template. During the process of calcium carbonate formation, [BMIM]BF4 acted not only as solvents but also as morphology templates for the fabrication of calcium carbonate materials with nacre-like morphology. Based on the observations, the possible mechanisms were also discussed. - Highlights: • Nacre-like CaCO3/GO were prepared by gas diffusion. • Ionic liquid/GO served as composite templates. • The interaction of Ca2+ ions and GO played a very important role in the formation of nacre-like CaCO3

  2. Enhancement of biodegradation and osseointegration of poly(ε-caprolactone)/calcium phosphate ceramic composite screws for osteofixation using calcium sulfate.

    Science.gov (United States)

    Wu, Chang-Chin; Hsu, Li-Ho; Tsai, Yuh-Feng; Sumi, Shoichiro; Yang, Kai-Chiang

    2016-04-01

    Internal fixation devices, which can stabilize and realign fractured bone, are widely used in fracture management. In this paper, a biodegradable composite fixator, composed of poly(ε-caprolactone), calcium phosphate ceramic and calcium sulfate (PCL/CPC/CS), is developed. The composition of CS, which has a high dissolution rate, was expected to create a porous structure to improve osteofixation to the composite fixator. PCL, PCL/CPC, and PCL/CPC/CS samples were prepared and their physical properties were characterized in vitro. In vivo performance of the composite screws was verified in the distal femurs of rabbits. Results showed that the PCL/CPC/CS composite had a higher compressive strength (28.55 ± 3.32 MPa) in comparison with that of PCL (20.64 ± 1.81 MPa) (p enhanced apatite formation of the PCL/CPC composite screw. This osteoconductive PCL/CPC/CS is a good candidate material for internal fixation devices. PMID:27041468

  3. Vibrational Damping of Composite Materials

    OpenAIRE

    Biggerstaff, Janet M.

    2006-01-01

    The purpose of this research was to develop new methods of vibrational damping in polymeric composite materials along with expanding the knowledge of currently used vibrational damping methods. A new barrier layer technique that dramatically increased damping in viscoelastic damping materials that interacted with the composite resin was created. A method for testing the shear strength of damping materials cocured in composites was developed. Directional damping materials, where the loss facto...

  4. Development of highly-filled, bioactive acrylic-based composite bone cements for orthopedic and craniofacial surgery: Tuning of material properties after incorporation of calcium phosphate and antimicrobial fillers

    Science.gov (United States)

    Rodriguez, Lucas Carlos

    Bone cements are used in a variety of healthcare specialties ranging from orthopedics to dentistry to craniofacial surgery to spinal disc reconstruction. These materials need characteristics which mimic their surrounding tissues. Currently available materials have struggled to maintain these necessary characteristics. Poly (methyl methacrylate) is a very high strength bio-inert polymer which has been utilized in healthcare since the 1940's. Calcium phosphate cements are well established as being bone mimicking, but cannot sustain the compressive loads in a weight bearing application. This study sought to solve the problem of currently available bone cements by filling calcium phosphates and antimicrobials into an acrylic polymer matrix. The intended outcome was a material capable of retaining high mechanical stability from the acrylic polymer phase, while becoming sufficiently bone mimicking and antimicrobial. This thesis work presented, characterizes the material properties of the developed materials and eventually isolates a material of interest for future studies.

  5. Evaluation of implant calcium-phosphate materials depending on their mineral content

    Directory of Open Access Journals (Sweden)

    I. A. Talashova

    2016-03-01

    Full Text Available Biocompatibility of original implant calcium-phosphate materials was evaluated in the experiment on animals. The methods of radiological electron-probe microanalysis (REMA and light and scan electron microscopy (SEM were used. Studied materials had the properties of biodegradation, osteoinduction and osteoconduction at different extent. The materials with the composite maximally close to the the bone tissue had the greatest grade of biocompatibility.

  6. Composite materials design and applications

    CERN Document Server

    Gay, Daniel; Tsai, Stephen W

    2002-01-01

    PART ONE. PRINCIPLES OF CONSTRUCTIONCOMPOSITE MATERIALS, INTEREST AND PROPERTIESWhat is Composite Material Fibers and MatrixWhat can be Made Using Composite Materials?Typical Examples of Interest on the Use of Composite MaterialsExamples on Replacing Conventional Solutions with CompositesPrincipal Physical PropertiesFABRICATION PROCESSESMolding ProcessesOther Forming ProcessesPractical Hints in the Manufacturing ProcessesPLY PROPERTIESIsotropy and AnisotropyCharacteristics of the Reinforcement-Matrix MixtureUnidirectional PlyWoven FabricsMats and Reinforced MatricesMultidimensional FabricsMetal Matrix CompositesTestsSANDWICH STRUCTURES:What is a Sandwich Structure?Simplified FlexureA Few Special AspectsFabrication and Design ProblemsNondestructive Quality ControlCONCEPTION AND DESIGNDesign of a Composite PieceThe LaminateFailure of LaminatesSizing of LaminatesJOINING AND ASSEMBLYRiveting and BoltingBondingInsertsCOMPOSITE MATERIALS AND AEROSPACE CONSTRUCTIONAircraftHelicoptersPropeller Blades for AirplanesTur...

  7. Composite material and method for production of improved composite material

    Science.gov (United States)

    Farley, Gary L. (Inventor)

    1996-01-01

    A laminated composite material with improved interlaminar strength and damage tolerance having short rods distributed evenly throughout the composite material perpendicular to the laminae. Each rod is shorter than the thickness of the finished laminate, but several times as long as the thickness of each lamina. The laminate is made by inserting short rods in layers of prepreg material, and then stacking and curing prepreg material with rods inserted therethrough.

  8. Calcium isotopic composition of mantle peridotites

    Science.gov (United States)

    Huang, F.; Kang, J.; Zhang, Z.

    2015-12-01

    Ca isotopes are useful to decipher mantle evolution and the genetic relationship between the Earth and chondrites. It has been observed that Ca isotopes can be fractionated at high temperature [1-2]. However, Ca isotopic composition of the mantle peridotites and fractionation mechanism are still poorly constrained. Here, we report Ca isotope composition of 12 co-existing pyroxene pairs in 10 lherzolites, 1 harzburgite, and 1 wehrlite xenoliths collected from Hainan Island (South Eastern China). Ca isotope data were measured on a Triton-TIMS using the double spike method at the Guangzhou Institute of Geochemistry, CAS. The long-term external error is 0.12‰ (2SD) based on repeated analyses of NIST SRM 915a and geostandards. δ44Ca of clinopyroxenes except that from the wehrlite ranges from 0.85‰ to 1.14‰, while opx yields a wide range from 0.98‰ up to 2.16‰. Co-existing pyroxene pairs show large ∆44Caopx-cpx (defined as δ44Caopx-δ44Cacpx) ranging from 0 to 1.23‰, reflecting equilibrium fractionation controlled by variable Ca contents in the opx. Notably, clinopyroxene of wehrlite shows extremely high δ44Ca (3.22‰). δ44Ca of the bulk lherzolites and harzburgites range from 0.86‰ to 1.14‰. This can be explained by extracting melts with slightly light Ca isotopic compositions. Finally, the high δ44Ca of the wehrlite (3.22‰) may reflect metasomatism by melt which has preferentially lost light Ca isotopes due to chemical diffusion during upwelling through the melt channel. [1] Amini et al (2009) GGR 33; [2] Huang et al (2010) EPSL 292.

  9. Calcium silicate hydrates: Solid and liquid phase composition

    International Nuclear Information System (INIS)

    This paper presents a review on the relationship between the composition, the structure and the solution in which calcium silicate hydrate (C–S–H) is equilibrated. The silica chain length in C–S–H increases with the silicon concentration and the calcium content in the interlayer space with the calcium concentrations. Sodium and potassium are taken up in the interlayer space, preferentially at low calcium concentrations and thus by low Ca/Si C–S–H. Aluminium uptake in C–S–H increases strongly at higher aluminium concentrations in the solution. At low Ca/Si, aluminium substitutes silica in the bridging position, at Ca/Si > 1 aluminium is bound in TAH. Recently developed thermodynamic models are closely related to the structure of C–S–H and tobermorite, and able to model not only the solubility and the chemical composition of the C–S–H, but also to predict the mean silica chain length and the uptake of aluminium

  10. Calcium silicate hydrates: Solid and liquid phase composition

    Energy Technology Data Exchange (ETDEWEB)

    Lothenbach, Barbara, E-mail: Barbara.lothenbach@empa.ch [Laboratory Concrete & Construction Chemistry, Empa (Switzerland); Nonat, André [ICB, UMR CNRS 6303 CNRS-Université de Bourgogne, Faculté des Sciences et Techniques, BP47870, 21078 Dijon Cedex (France)

    2015-12-15

    This paper presents a review on the relationship between the composition, the structure and the solution in which calcium silicate hydrate (C–S–H) is equilibrated. The silica chain length in C–S–H increases with the silicon concentration and the calcium content in the interlayer space with the calcium concentrations. Sodium and potassium are taken up in the interlayer space, preferentially at low calcium concentrations and thus by low Ca/Si C–S–H. Aluminium uptake in C–S–H increases strongly at higher aluminium concentrations in the solution. At low Ca/Si, aluminium substitutes silica in the bridging position, at Ca/Si > 1 aluminium is bound in TAH. Recently developed thermodynamic models are closely related to the structure of C–S–H and tobermorite, and able to model not only the solubility and the chemical composition of the C–S–H, but also to predict the mean silica chain length and the uptake of aluminium.

  11. Composite Materials in Overhead Lines

    DEFF Research Database (Denmark)

    Sørensen, Thomas Kjærsgaard; Holbøll, Joachim

    2009-01-01

    The use of composite materials, e.g. fibreglass materials, in overhead transmission line systems is nothing new. Composite based insulators have been applied to transmission lines for over 30 years, mainly as suspension and post insulators and often as an option for special applications. Also...... respect to solved and persisting known failures/problems of both mechanical and electrical nature. Major challenges related to extensive use of composite materials in an overhead line system are identified, as are possible benefits - both when using standard as well as customised composite components, e...... towers and recently conductors based on composite materials are available at transmission levels. In this paper it is investigated which composite based solutions are available in connection with complete overhead line systems including insulators, towers and conductors. The components are reviewed with...

  12. Preparation and properties of gluten/calcium carbonate composites

    Institute of Scientific and Technical Information of China (English)

    Min Zuo; Zheng Zheng Lai; Yi Hu Song; Qiang Zheng

    2008-01-01

    Environment friendly thermosetting composites were prepared by blending wheat gluten (WG) as matrix, calcium carbonate (CaCO3) as filler and glycerol as plasticizer followed by compression molding the mixture at 120 ℃ to crosslink the WG matrix. Morphology observation showed that the CaCO3 particles were finely dispersed in matrix. Incorporation of CaCO3 up to 10 wt% into the composites caused Young's modulus and tensile strength to increase markedly. On the other hand, the moisture absorption and elongation at break decreased slightly.

  13. Optimizing and Evaluating the Biocompatibility of Fiber Composites with Calcium Phosphate Additives

    Czech Academy of Sciences Publication Activity Database

    Suchý, Tomáš; Balík, Karel; Sucharda, Zbyněk; Sochor, M.; Lapčíková, Monika; Sedláček, R.

    2011-01-01

    Roč. 161, 19/20 (2011), s. 493-502. ISSN 0043-5341 R&D Projects: GA ČR(CZ) GAP108/10/1457; GA ČR(CZ) GA106/06/1576 Institutional research plan: CEZ:AV0Z30460519; CEZ:AV0Z40500505 Keywords : biocomposites * calcium phosphate * polyamide fibers Subject RIV: JI - Composite Materials http://www.springerlink.com/content/047q753g04h4l836/

  14. Fatigue in Composite Materials

    Science.gov (United States)

    1984-01-01

    The deformation and failure behavior of graphite/epoxy tubes under biaxial loading was investigated. The increase of basic understanding of and provide design information for the bi-axial response of graphite/epoxy composites to fatigue loads are considered.

  15. Experimental and Modeling Study of the Turning Process of PA 6/Nano Calcium Carbonate Composite

    Directory of Open Access Journals (Sweden)

    Mehdi Haghi

    2013-01-01

    Full Text Available Nowadays, polymeric nanocomposites have emerged as a new material class with rapidly growing use in industrial products because of good mechanical, thermal, and physical properties. Recently, the requirement of the direct machining of these materials has increased due to the production of the most of them by extrusion method in simple cross section and the increased demand for personalized products. In this work, the effect of turning parameters (cutting speed and feed and nano calcium carbonate content on the machinability properties of polyamide 6/nano calcium carbonate composites was investigated by analysis of variance. A novel modeling approach of modified harmony search-based neural network was also utilized to create predictive models of surface roughness and total cutting force from the experimental data. The results revealed that the nano calcium carbonate content on polyamide 6 decreased the cutting forces significantly but did not have a significant effect on surface roughness. Moreover, the results for modeling total cutting forces and surface roughness showed that modified harmony search-based neural network is effective, reliable, and authoritative in modeling the turning process of polyamide 6/nano calcium carbonate composite.

  16. Comparative study on in vivo response of porous calcium carbonate composite ceramic and biphasic calcium phosphate ceramic.

    Science.gov (United States)

    He, Fupo; Ren, Weiwei; Tian, Xiumei; Liu, Wei; Wu, Shanghua; Chen, Xiaoming

    2016-07-01

    In a previous study, robust calcium carbonate composite ceramics (CC/PG) were prepared by using phosphate-based glass (PG) as an additive, which showed good cell response. In the present study the in vivo response of porous CC/PG was compared to that of porous biphasic calcium phosphate ceramics (BCP), using a rabbit femoral critical-size grafting model. The materials degradation and bone formation processes were evaluated by general observation, X-ray radiography, micro-computed tomography, and histological examination. The results demonstrated excellent biocompatibility and osteoconductivity, and progressive degradation of CC/PG and BCP. Although the in vitro degradation rate of CC/PG was distinctly faster than that of BCP, at 4week post-implantation, the bone generation and material degradation of CC/PG were less than those of BCP. Nevertheless, at postoperative week 8, the increment of bone formation and material degradation of CC/PG was pronouncedly larger than that of BCP. These results show that CC/PG is a potential resorbable bone graft aside from the traditional synthetic ones. PMID:27127035

  17. Monolithic calcium phosphate/poly(lactic acid) composite versus calcium phosphate-coated poly(lactic acid) for support of osteogenic differentiation of human mesenchymal stromal cells

    OpenAIRE

    Tahmasebi Birgani, Zeinab; van Blitterswijk, Clemens A; Habibovic, Pamela

    2016-01-01

    Calcium phosphates (CaPs), extensively used synthetic bone graft substitutes, are often combined with other materials with the aim to overcome issues related to poor mechanical properties of most CaP ceramics. Thin ceramic coatings on metallic implants and polymer-ceramic composites are examples of such hybrid materials. Both the properties of the CaP used and the method of incorporation into a hybrid structure are determinant for the bioactivity of the final construct. In the present study, ...

  18. Coating material composition

    International Nuclear Information System (INIS)

    A polyester composition is provided for forming a hard and weather-proof coating easily hardened by irradiation with active energy, particularly electron beams, using a mixture of a polyester component containing a dimer of methacrylate as an acid group with an oligomer having at least two vinyl radicals in one molecule. The composition consists of 10%-90% by weight of at least one (a) methacrylic dimer or unsaturated polyester containing its methyl ester as an acid group, (b) telomerized diacrylpolyester or (c) telomerized fiberous polyester having at its distal end a dimer of methacrylate residue, and 90%-10% of a low molecular weight compound having at least two polymerizable unsaturated radicals. The low molecular weight compound is produced by reacting at first saturated cyclic carboxylic anhydride and/or alpha-, beta-ethylenic unsaturated carboxylic anhydride and secondarily a vinyl monomer containing epoxy-radicals with hydroxyl radical-containing vinyl monomer and/or polyhydric alcohol. The aforesaid methacrylic acid dimer dimethyl ester is a byproduct of methyl methacrylate synthesis. This produces monoester monocarboxylic acid or dicarboxylic acid by hydrolysis. In one example, a polyester (a-1) was produced by reacting 0.5 moles of methacrylic acid dimer, 0.5 mol of adipic acid, 1,25 mole of ethylene glycol and 0.005 mol of hydroquinone monomethyl ether. On the other hand, an orgomer (d) is obtained from 1 mol of 2-hydroxyl ethyl methacrylate, 1 mol of maleic anhydride, 0.005 mol of hydroquinon monomethyl ether and 1 mol of glycidyl methacrylate. Next, 80 parts of (a-1) and 20 parts of (d) were mixed. (Iwakiri, K.)

  19. Multilayer Electroactive Polymer Composite Material

    Science.gov (United States)

    Ounaies, Zoubeida (Inventor); Park, Cheol (Inventor); Harrison, Joycelyn S. (Inventor); Holloway, Nancy M. (Inventor); Draughon, Gregory K. (Inventor)

    2011-01-01

    An electroactive material comprises multiple layers of electroactive composite with each layer having unique dielectric, electrical and mechanical properties that define an electromechanical operation thereof when affected by an external stimulus. For example, each layer can be (i) a 2-phase composite made from a polymer with polarizable moieties and an effective amount of carbon nanotubes incorporated in the polymer for a predetermined electromechanical operation, or (ii) a 3-phase composite having the elements of the 2-phase composite and further including a third component of micro-sized to nano-sized particles of an electroactive ceramic incorporated in the polymer matrix.

  20. Preparation of novel bioactive nano-calcium phosphate-hydrogel composites

    Energy Technology Data Exchange (ETDEWEB)

    Juhasz, Judith A; Best, Serena M; Bonfield, William, E-mail: jaj33@cam.ac.u [Department of Materials Science and Metallurgy, University of Cambridge, Pembroke Street, Cambridge CB2 3QZ (United Kingdom)

    2010-02-15

    Nano-sized hydroxyapatite (nHA) and carbonate-substituted hydroxyapatite (nCHA) particles were incorporated into a poly-2-hydroxyethylmethacrylate/polycaprolactone (PHEMA/PCL) hydrogel at a filler content of 10 wt%. Fourier transform infrared absorption, transmission electron microscopy, x-ray diffraction and scanning electron microscopy were used to analyse the physical and chemical characteristics of the calcium phosphate fillers and resultant composites. Nano-sized calcium phosphate particles were produced with a needle-like morphology, average length of 50 nm and an aspect ratio of 3. The nanoparticles were uniformly distributed in the polymer matrix. The addition of both HA and CHA in nano-form enhanced the bioactivity and biocompatibility of the PHEMA/PCL matrix. The carbonate-substitution has allowed for improved bioactivity and biocompatibility of the resultant composite, indicating the potential of this material for use in bone tissue engineering.

  1. Preparation of novel bioactive nano-calcium phosphate-hydrogel composites

    International Nuclear Information System (INIS)

    Nano-sized hydroxyapatite (nHA) and carbonate-substituted hydroxyapatite (nCHA) particles were incorporated into a poly-2-hydroxyethylmethacrylate/polycaprolactone (PHEMA/PCL) hydrogel at a filler content of 10 wt%. Fourier transform infrared absorption, transmission electron microscopy, x-ray diffraction and scanning electron microscopy were used to analyse the physical and chemical characteristics of the calcium phosphate fillers and resultant composites. Nano-sized calcium phosphate particles were produced with a needle-like morphology, average length of 50 nm and an aspect ratio of 3. The nanoparticles were uniformly distributed in the polymer matrix. The addition of both HA and CHA in nano-form enhanced the bioactivity and biocompatibility of the PHEMA/PCL matrix. The carbonate-substitution has allowed for improved bioactivity and biocompatibility of the resultant composite, indicating the potential of this material for use in bone tissue engineering.

  2. Ionic liquid-assisted formation of cellulose/calcium phosphate hybrid materials

    OpenAIRE

    Ahmed Salama; Mike Neumann; Christina Günter; Andreas Taubert

    2014-01-01

    Cellulose/calcium phosphate hybrid materials were synthesized via an ionic liquid-assisted route. Scanning electron microscopy, transmission electron microscopy, energy-dispersive X-ray spectroscopy, X-ray diffraction, infrared spectroscopy, and thermogravimetric analysis/differential thermal analysis show that, depending on the reaction conditions, cellulose/hydroxyapatite, cellulose/chlorapatite, or cellulose/monetite composites form. Preliminary studies with MC3T3-E1 pre-osteoblasts show t...

  3. Genetic Homogenization of Composite Materials

    Directory of Open Access Journals (Sweden)

    P. Tobola

    2009-04-01

    Full Text Available The paper is focused on numerical studies of electromagnetic properties of composite materials used for the construction of small airplanes. Discussions concentrate on the genetic homogenization of composite layers and composite layers with a slot. The homogenization is aimed to reduce CPU-time demands of EMC computational models of electrically large airplanes. First, a methodology of creating a 3-dimensional numerical model of a composite material in CST Microwave Studio is proposed focusing on a sufficient accuracy of the model. Second, a proper implementation of a genetic optimization in Matlab is discussed. Third, an association of the optimization script and a simplified 2-dimensional model of the homogeneous equivalent model in Comsol Multiphysics is proposed considering EMC issues. Results of computations are experimentally verified.

  4. Ionic liquid-assisted formation of cellulose/calcium phosphate hybrid materials

    Directory of Open Access Journals (Sweden)

    Ahmed Salama

    2014-09-01

    Full Text Available Cellulose/calcium phosphate hybrid materials were synthesized via an ionic liquid-assisted route. Scanning electron microscopy, transmission electron microscopy, energy-dispersive X-ray spectroscopy, X-ray diffraction, infrared spectroscopy, and thermogravimetric analysis/differential thermal analysis show that, depending on the reaction conditions, cellulose/hydroxyapatite, cellulose/chlorapatite, or cellulose/monetite composites form. Preliminary studies with MC3T3-E1 pre-osteoblasts show that the cells proliferate on the hybrid materials suggesting that the ionic liquid-based process yields materials that are potentially useful as scaffolds for regenerative therapies.

  5. Sintered composite gradient tool materials

    OpenAIRE

    J. Mikuła; G. Matula; K. Gołombek; L.A. Dobrzański

    2008-01-01

    Purpose: Development of a new generation of the composite gradient tool materials with the core sintered withthe matrix obtained using the powder metallurgy of the chemical composition corresponding to the HS6-5-2 highspeedsteel reinforced with the WC and TiC type hard carbide phases with the growing portions of these phases inthe outward direction from the core to the surface.Design/methodology/approach: Powder Metallurgy, SEM, X-Ray Microanalysis.Findings: Powder metallurgy processes were u...

  6. Fracture problems in composite materials

    Science.gov (United States)

    Erdogan, F.

    1972-01-01

    A series of fracture problems in composite materials are identified, their methods of solution are briefly discussed, and some sample results are presented. The main problem of interest is the determination of the stress state in the neighborhood of localized imperfections such as cracks and inclusions which may exist in the composite. Particular emphasis is placed on the evaluation of quantities such as the stress intensity factors, the power of the stress singularity, and the strain energy release rate, which may be used directly or indirectly in connection with an appropriate fracture criterion for the prediction of fracture initiation and propagation load levels. The topics discussed include a crack in layered composites, a crack terminating at and going through a bi-material interface, a penny-shaped crack in a filament-reinforced elastic matrix, and inclusion problems in bonded materials.

  7. Lightweight, Thermally Conductive Composite Material

    Science.gov (United States)

    Sharp, G. Richard; Loftin, Timothy A.

    1990-01-01

    Aluminum reinforced with carbon fibers superior to copper in some respects. Lightweight composite material has high thermal conductivity. Consists of aluminum matrix containing graphite fibers, all oriented in same direction. Available as sheets, tubes, and bars. Thermal conductivity of composite along fibers rises above that of pure copper over substantial range of temperatures. Graphite/aluminum composite useful in variety of heat-transfer applications in which reduction of weight critical. Used to conduct heat in high-density, high-speed integrated-circuit packages for computers and in base plates for electronic equipment. Also used to carry heat away from leading edges of wings in high-speed airplanes.

  8. Effective Thermal Conductivity Analysis of Xonotlite-aerogel Composite Insulation Material

    Institute of Scientific and Technical Information of China (English)

    Gaosheng WEI; Xinxin ZHANG; Fan YU

    2009-01-01

    A 3-dimensional unit cell model is developed for analyzing effective thermal conductivity of xonotlite-aerogel composite insulation material based on its microstructure features. Effective thermal conductivity comparisons between xonotlite-type calcium silicate and aerogel as well as xonotlite-aerogei composite insulation material are presented. It is shown that the density of xonotlite-type calcium silicate is the key factor affecting the effective thermal conductivity of xonotlite-aerogel composite insulation material, and the density of aerogel has tittle in-fluence. The effective thermal conductivity can be lowered greatly by composite of the two materials at an ele-vated temperature.

  9. Injectable Hydrogel Composite Based Gelatin-PEG and Biphasic Calcium Phosphate Nanoparticles for Bone Regeneration

    Science.gov (United States)

    Van, Thuy Duong; Tran, Ngoc Quyen; Nguyen, Dai Hai; Nguyen, Cuu Khoa; Tran, Dai Lam; Nguyen, Phuong Thi

    2016-05-01

    Gelatin hydrogels have recently attracted much attention for tissue regeneration because of their biocompatibility. In this study, we introduce poly-ethylene glycol (PEG)—grafted gelatin containing tyramine moieties which have been utilized for in situ enzyme-mediated hydrogel preparation. The hydrogel can be used to load nanoparticles of biphasic calcium phosphate, a mixture of hydroxyapatite and β-tricalcium phosphate, and forming injectable bio-composites. Proton nuclear magnetic resonance (1H NMR) spectra indicated that tyramine-functionalized polyethylene glycol-nitrophenyl carbonate ester was conjugated to the gelatin. The hydrogel composite was rapidly formed in situ (within a few seconds) in the presence of horseradish peroxidase and hydrogen peroxide. In vitro experiments with bio-mineralization on the hydrogel composite surfaces was well-observed after 2 weeks soaking in simulated body fluid solution. The obtained results indicated that the hydrogel composite could be a potential injectable material for bone regeneration.

  10. Osteogenic activity of cyclodextrin-encapsulated doxycycline in a calcium phosphate PCL and PLGA composite.

    Science.gov (United States)

    Trajano, V C C; Costa, K J R; Lanza, C R M; Sinisterra, R D; Cortés, M E

    2016-07-01

    Composites of biodegradable polymers and calcium phosphate are bioactive and flexible, and have been proposed for use in tissue engineering and bone regeneration. When associated with the broad-spectrum antibiotic doxycycline (DOX), they could favor antimicrobial action and enhance the action of osteogenic composites. Composites of polycaprolactone (PCL), poly(lactic-co-glycolic acid) (PLGA), and a bioceramic of biphasic calcium phosphate Osteosynt® (BCP) were loaded with DOX encapsulated in β-cyclodextrin (βCD) and were evaluated for effects on osteoblastic cell cultures. The DOX/βCD composite was prepared with a double mixing method. Osteoblast viability was assessed with methyl tetrazolium (MTT) assays after 1day, 7day, and 14days of composite exposure; alkaline phosphatase (AP) activity and collagen production were evaluated after 7days and 14days, and mineral nodule formation after 14days. Composite structures were evaluated by scanning electron microscopy (SEM). Osteoblasts exposed to the composite containing 25μg/mL DOX/βCD had increased cell proliferation (p<0.05) compared to control osteoblast cultures at all experimental time points, reaching a maximum in the second week. AP activity and collagen secretion levels were also elevated in osteoblasts exposed to the DOX/βCD composite (p<0.05 vs. controls) and reached a maximum after 14days. These results were corroborated by Von Kossa test results, which showed strong formation of mineralization nodules during the same time period. SEM of the composite material revealed a surface topography with pore sizes suitable for growing osteoblasts. Together, these results suggest that osteoblasts are viable, proliferative, and osteogenic in the presence of a DOX/βCD-containing BCP ceramic composite. PMID:27127066

  11. Joining of polymer composite materials

    Energy Technology Data Exchange (ETDEWEB)

    Magness, F.H.

    1990-11-01

    Under ideal conditions load bearing structures would be designed without joints, thus eliminating a source of added weight, complexity and weakness. In reality the need for accessibility, repair, and inspectability, added to the size limitations imposed by the manufacturing process and transportation/assembly requirements mean that some minimum number of joints will be required in most structures. The designer generally has two methods for joining fiber composite materials, adhesive bonding and mechanical fastening. As the use of thermoplastic materials increases, a third joining technique -- welding -- will become more common. It is the purpose of this document to provide a review of the available sources pertinent to the design of joints in fiber composites. The primary emphasis is given to adhesive bonding and mechanical fastening with information coming from documentary sources as old as 1961 and as recent as 1989. A third, shorter section on composite welding is included in order to provide a relatively comprehensive treatment of the subject.

  12. Composite Materials: An Educational Need.

    Science.gov (United States)

    Saliba, Tony E.; Snide, James A.

    1990-01-01

    Described is the need to incorporate the concepts and applications of advanced composite materials into existing chemical engineering programs. Discussed are the justification for, and implementation of topics including transport phenomena, kinetics and reactor design, unit operations, and product and process design. (CW)

  13. Mechanical Properties of Composite Materials

    Directory of Open Access Journals (Sweden)

    Mitsuhiro Okayasu

    2014-10-01

    Full Text Available An examination has been made of the mechanical and failure properties of several composite materials, such as a short and a long carbon fiber reinforced plastic (short- and long-CFRP and metal based composite material. The short CFRP materials were used for a recycled CFRP which fabricated by the following process: the CFRP, consisting of epoxy resin with carbon fiber, is injected to a rectangular plate cavity after mixing with acrylonitrile butadiene styrene resin with different weight fractions of CFRP. The fatigue and ultimate tensile strength (UTS increased with increasing CFRP content. These correlations, however, break down, especially for tensile strength, as the CFPR content becomes more than 70%. Influence of sample temperature on the bending strength of the long-CFRP was investigated, and it appears that the strength slightly decreases with increasing the temperature, due to the weakness in the matrix. Broken fiber and pull-out or debonding between the fiber and matrix were related to the main failure of the short- and long-CFRP samples. Mechanical properties of metal based composite materials have been also investigated, where fiber-like high hardness CuAl2 structure is formed in aluminum matrix. Excellent mechanical properties were obtained in this alloy, e.g., the higher strength and the higher ductility, compared tothe same alloy without the fiber-like structure. There are strong anisotropic effects on the mechanical properties due to the fiber-like metal composite in a soft Al based matrix.

  14. Creep of fibrous composite materials

    DEFF Research Database (Denmark)

    Lilholt, Hans

    1985-01-01

    Models are presented for the creep behaviour of fibrous composite materials with aligned fibres. The models comprise both cases where the fibres remain rigid in a creeping matrix and cases where the fibres are creeping in a creeping matrix. The treatment allows for several contributions to the...... creep strength of composites. The advantage of combined analyses of several data sets is emphasized and illustrated for some experimental data. The analyses show that it is possible to derive creep equations for the (in situ) properties of the fibres. The experiments treated include model systems such...

  15. Degradability of injectable calcium sulfate/mineralized collagen-based bone repair material and its effect on bone tissue regeneration

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Zonggang, E-mail: chenzg@sdu.edu.cn [National Glycoengineering Research Center, Shandong University, Jinan 250100 (China); Department of Materials Science and Engineering, Tsinghua University, Beijing 100084 (China); Kang, Lingzhi [National Glycoengineering Research Center, Shandong University, Jinan 250100 (China); Meng, Qing-Yuan [Department of Materials Science and Engineering, Tsinghua University, Beijing 100084 (China); Liu, Huanye [Department of Prosthodontics, School of Stomatology, China Medical University, Shenyang 110001 (China); Wang, Zhaoliang [Jinan Military General Hospital of PLA, Jinan 250031 (China); Guo, Zhongwu, E-mail: zwguo@sdu.edu.cn [National Glycoengineering Research Center, Shandong University, Jinan 250100 (China); Cui, Fu-Zhai, E-mail: cuifz@mail.tsinghua.edu.cn [Department of Materials Science and Engineering, Tsinghua University, Beijing 100084 (China)

    2014-12-01

    The nHAC/CSH composite is an injectable bone repair material with controllable injectability and self-setting properties prepared by introducing calcium sulfate hemihydrate (CSH) into mineralized collagen (nHAC). When mixed with water, the nHAC/CSH composites can be transformed into mineralized collagen/calcium sulfate dihydrate (nHAC/CSD) composites. The nHAC/CSD composites have good biocompatibility and osteogenic capability. Considering that the degradation behavior of bone repair material is another important factor for its clinical applications, the degradability of nHAC/CSD composites was studied. The results showed that the degradation ratio of the nHAC/CSD composites with lower nHAC content increased with the L/S ratio increase of injectable materials, but the variety of L/S ratio had no significant effect on the degradation ratio of the nHAC/CSD composites with higher nHAC content. Increasing nHAC content in the composites could slow down the degradation of nHAC/CSD composite. Setting accelerator had no significant effect on the degradability of nHAC/CSD composites. In vivo histological analysis suggests that the degradation rate of materials can match the growth rate of new mandibular bone tissues in the implanted site of rabbit. The regulable degradability of materials resulting from the special prescriptions of injectable nHAC/CSH composites will further improve the workability of nHAC/CSD composites. - Highlights: • The nHAC/CSH composite can be as an injectable bone repair material. • The L/S ratio and nHAC content have a significant effect on material degradability. • The degradability of bone materials can be regulated to match tissue repair. • The regulable degradability will further improve the workability of bone materials.

  16. Degradability of injectable calcium sulfate/mineralized collagen-based bone repair material and its effect on bone tissue regeneration

    International Nuclear Information System (INIS)

    The nHAC/CSH composite is an injectable bone repair material with controllable injectability and self-setting properties prepared by introducing calcium sulfate hemihydrate (CSH) into mineralized collagen (nHAC). When mixed with water, the nHAC/CSH composites can be transformed into mineralized collagen/calcium sulfate dihydrate (nHAC/CSD) composites. The nHAC/CSD composites have good biocompatibility and osteogenic capability. Considering that the degradation behavior of bone repair material is another important factor for its clinical applications, the degradability of nHAC/CSD composites was studied. The results showed that the degradation ratio of the nHAC/CSD composites with lower nHAC content increased with the L/S ratio increase of injectable materials, but the variety of L/S ratio had no significant effect on the degradation ratio of the nHAC/CSD composites with higher nHAC content. Increasing nHAC content in the composites could slow down the degradation of nHAC/CSD composite. Setting accelerator had no significant effect on the degradability of nHAC/CSD composites. In vivo histological analysis suggests that the degradation rate of materials can match the growth rate of new mandibular bone tissues in the implanted site of rabbit. The regulable degradability of materials resulting from the special prescriptions of injectable nHAC/CSH composites will further improve the workability of nHAC/CSD composites. - Highlights: • The nHAC/CSH composite can be as an injectable bone repair material. • The L/S ratio and nHAC content have a significant effect on material degradability. • The degradability of bone materials can be regulated to match tissue repair. • The regulable degradability will further improve the workability of bone materials

  17. Method of tissue repair using a composite material

    Science.gov (United States)

    Hutchens, Stacy A.; Woodward, Jonathan; Evans, Barbara R.; O'Neill, Hugh M.

    2016-03-01

    A composite biocompatible hydrogel material includes a porous polymer matrix, the polymer matrix including a plurality of pores and providing a Young's modulus of at least 10 GPa. A calcium comprising salt is disposed in at least some of the pores. The porous polymer matrix can comprise cellulose, including bacterial cellulose. The composite can be used as a bone graft material. A method of tissue repair within the body of animals includes the steps of providing a composite biocompatible hydrogel material including a porous polymer matrix, the polymer matrix including a plurality of pores and providing a Young's modulus of at least 10 GPa, and inserting the hydrogel material into cartilage or bone tissue of an animal, wherein the hydrogel material supports cell colonization in vitro for autologous cell seeding.

  18. Method of tissue repair using a composite material

    Energy Technology Data Exchange (ETDEWEB)

    Hutchens, Stacy A.; Woodward, Jonathan; Evans, Barbara R.; O' Neill, Hugh M.

    2016-03-01

    A composite biocompatible hydrogel material includes a porous polymer matrix, the polymer matrix including a plurality of pores and providing a Young's modulus of at least 10 GPa. A calcium comprising salt is disposed in at least some of the pores. The porous polymer matrix can comprise cellulose, including bacterial cellulose. The composite can be used as a bone graft material. A method of tissue repair within the body of animals includes the steps of providing a composite biocompatible hydrogel material including a porous polymer matrix, the polymer matrix including a plurality of pores and providing a Young's modulus of at least 10 GPa, and inserting the hydrogel material into cartilage or bone tissue of an animal, wherein the hydrogel material supports cell colonization in vitro for autologous cell seeding.

  19. Method of tissue repair using a composite material

    Energy Technology Data Exchange (ETDEWEB)

    Hutchens, Stacy A; Woodward, Jonathan; Evans, Barbara R; O' Neill, Hugh M

    2014-03-18

    A composite biocompatible hydrogel material includes a porous polymer matrix, the polymer matrix including a plurality of pores and providing a Young's modulus of at least 10 GPa. A calcium comprising salt is disposed in at least some of the pores. The porous polymer matrix can comprise cellulose, including bacterial cellulose. The composite can be used as a bone graft material. A method of tissue repair within the body of animals includes the steps of providing a composite biocompatible hydrogel material including a porous polymer matrix, the polymer matrix including a plurality of pores and providing a Young's modulus of at least 10 GPa, and inserting the hydrogel material into cartilage or bone tissue of an animal, wherein the hydrogel material supports cell colonization in vitro for autologous cell seeding.

  20. INTELLIGENT MATERIALS BASED ON CERAMIC COMPOSITES

    OpenAIRE

    Maximov, Y.; Merzlikin, V.; Sidorov, O.; Suttugin, V.

    2010-01-01

    The paper examines the possibility to design intellectual materials based on film composites. Ferroelectric composites are offered to use as the film composites. The authors discuss ferroelectric composites of different structures. Sensors and intellectual materials on the basis of the obtained composites are considered.

  1. Selective laser sintering of calcium phosphate materials for orthopedic implants

    Science.gov (United States)

    Lee, Goonhee

    Two technologies, Solid Freeform Fabrication (SFF) and bioceramics are combined in this work to prepare bone replacement implants with complex geometry. SFF has emerged as a crucial technique for rapid prototyping in the last decade. Selective Laser Sintering (SLS) is one of the established SFF manufacturing processes that can build three-dimensional objects directly from computer models without part-specific tooling or human intervention. Meanwhile, there have been great efforts to develop implantable materials that can assist in regeneration of bone defects and injuries. However, little attention has been focused in shaping bones from these materials. The main thrust of this research was to develop a process that can combine those two separate efforts. The specific objective of this research is to develop a process that can construct bone replacement material of complex geometry from synthetic calcium phosphate materials by using the SLS process. The achievement of this goal can have a significant impact on the quality of health care in the sense that complete custom-fit bone and tooth structures suitable for implantation can be prepared within 24--48 hours of receipt of geometric information obtained either from patient Computed Tomographic (CT) data, from Computer Aided Design (CAD) software or from other imaging systems such as Magnetic Resonance Imaging (MRI) and Holographic Laser Range Imaging (HLRI). In this research, two different processes have been developed. First is the SLS fabrication of porous bone implants. In this effort, systematic procedures have been established and calcium phosphate implants were successfully fabricated from various sources of geometric information. These efforts include material selection and preparation, SLS process parameter optimization, and development of post-processing techniques within the 48-hour time frame. Post-processing allows accurate control of geometry and of the chemistry of calcium phosphate, as well as

  2. Coating of calcium phosphate on biometallic materials by electrophoretic deposition

    Institute of Scientific and Technical Information of China (English)

    ZHANG Er-lin; YANG Ke

    2005-01-01

    Although biometallic materials have been used as bone implant materials for a long time, they are still detected as foreign bodies by human immune system. Calcium phosphate coating, especially hydroxyapatite(HA)coating attracts special attention due to its good biocompatibility. Being one of the effective methods used to deposit HA coating onto the metallic implant, the electrophoretic deposition(EPD) was reviewed in detail, including the process of EPD, the advantages and disadvantages, the important processing factors and the microstructure and mechanical properties of the coating. Research results on the processing and the coating show potential application of EPD process to the biomedical materials surface modification. In addition, the nanoparticulate HA coating as a new trend in HA coating was also introduced.

  3. Improved Silica Aerogel Composite Materials

    Science.gov (United States)

    Paik, Jong-Ah; Sakamoto, Jeffrey; Jones, Steven

    2008-01-01

    A family of aerogel-matrix composite materials having thermal-stability and mechanical- integrity properties better than those of neat aerogels has been developed. Aerogels are known to be excellent thermal- and acoustic-insulation materials because of their molecular-scale porosity, but heretofore, the use of aerogels has been inhibited by two factors: (1) Their brittleness makes processing and handling difficult. (2) They shrink during production and shrink more when heated to high temperatures during use. The shrinkage and the consequent cracking make it difficult to use them to encapsulate objects in thermal-insulation materials. The underlying concept of aerogel-matrix composites is not new; the novelty of the present family of materials lies in formulations and processes that result in superior properties, which include (1) much less shrinkage during a supercritical-drying process employed in producing a typical aerogel, (2) much less shrinkage during exposure to high temperatures, and (3) as a result of the reduction in shrinkage, much less or even no cracking.

  4. α-半水硫酸钙/辛伐他汀/万古霉素复合材料抗菌和细胞毒性作用的研究%Antibacterial properties and cytotoxicity of alpha half water calcium sulfate/simvastatin/vancomycin composite materials

    Institute of Scientific and Technical Information of China (English)

    陈建民; 曹华; 刘方刚; 柯荣军; 端礼荣

    2013-01-01

    [ Objective ] Escherichia coli and staphylococcus aureus, the pseudomonas aeruginosa by alpha half water calcium sulfate/simvastatin/vancomycin composite materials, and the cytotoxicity of new osteoblast cells in mice by in vitro were studied. [ Methods ] With the qualitative and quantitative of bacteria inhibition growth experiments, the diameters and antibacterial rates of Staphylococcus aureus ATCC25923, escherichia coli ATCC25922, pseudomonas aeruginosa ATCC27853 were determined under the affection of contained different concentrations of alpha half water calcium sulfate/simvastatin/vancomycin composite materials. The cytotoxicity tests of the alpha half water calcium sulfate/simvastatin/vancomycin composite materials on the new osteoblast cells in mice was made to evaluate the saftywith MTT cytotoxicity assay. [Results] Containing 5, 10, 20 u,g/ml alpha half water calcium sulfate/simvastatin/vancomycin composite materials for newborn mice osteogenesis cell concentration - effect relations on staphylococcus aureus and escherichia coli bacteriostatic circle diameter were 28, 30, 33 mm and 24, 23, 25 mm, including 0.2%, 0.4%, 8%, 1.0%. To pseudomonas aeruginosa ATCC27853 had no bacteriostasis. [ Conclusion ] The alpha half water calcium sulfate/simvastatin/vancomycin composite material leaching solution of toxic reaction level in 2 below level, are the basic of cell toxicity, they have good antibacterial effect, cells with good compatibility, and can promote bone cell proliferation and differentiation.%[目的]研究不同浓度配比α-半水硫酸钙/辛伐他汀/万古霉素复合材料的体外抗金黄色葡萄球菌、大肠埃希菌和铜绿假单胞菌的作用,以及α-半水硫酸钙/辛伐他汀/万古霉素复合材料浸提液对新生小鼠成骨细胞的毒性作用.[方法]采用细菌生长抑制的定性和定量试验测定抑菌圈直径、抑菌率;MTT法细胞毒性试验测定α-半水硫酸钙/辛伐他汀/万古霉素复合材料浸

  5. A Review of Biomedical Composite Materials

    Institute of Scientific and Technical Information of China (English)

    吴珊珊

    2013-01-01

    This article addresses the review of the biomedical composite materials.It introduces the operational definition,the classification of biomedical composite materials,and its constituents within itself.In this thesis,the last part presents the application of this kind of material.By writing this paper,I hope that people will get a comprehensive knowledge of the biomedical composite material and make further and deeper research in this material by which way to animate the material science industry.

  6. Dibasic calcium phosphate dihydrate, USP material compatibility with gamma radiation

    Science.gov (United States)

    Betancourt Quiles, Maritza

    Gamma radiation is a commonly used method to reduce the microbial bioburden in compatible materials when it is applied at appropriate dose levels. Gamma irradiation kills bacteria and mold by breaking down the organism’s DNA and inhibiting cell division. The purpose of this study is to determine the radiation dosage to be used to treat Dibasic Calcium Phosphate Dihydrate, USP (DCPD) and to evaluate its physicochemical effects if any, on this material. This material will be submitted to various doses of gamma radiation that were selected based on literature review and existing regulations that demonstrate that this method is effective to reduce or eliminate microbial bioburden in natural source and synthetic materials. Analytical testing was conducted to the DCPD exposed material in order to demonstrate that gamma radiation does not alter the physicochemical properties and material still acceptable for use in the manufacture of pharmaceutical products. The results obtained through this study were satisfactory and demonstrated that the gamma irradiation dosages from 5 to 30 kGy can be applied to DCPD without altering its physicochemical properties. These are supported by the Assay test data evaluation of lots tested before and after gamma irradiation implementation that show no significant statistical difference between irradiated and non irradiated assay results. The results of this study represent an achievement for the industry since they provide as an alternative the use of Gamma irradiation technology to control the microbial growth in DCPD.

  7. Multiscale damage modeling of advanced composite materials

    OpenAIRE

    Menna, Costantino

    2013-01-01

    The use of composite materials has spread over the years throughout the engineering areas of structures. The technological progress in this field has recently expanded, resulting in the design of new composite configurations, including multilayered composite materials and multifunctional nanostructured materials. Even though traditional and emerging composite materials offer wide potentialities for engineering, a significant challenge is still open with respect to damage phenomena. Driven by ...

  8. Biocompatibility optimization of fabric composites by calcium phosphates

    Czech Academy of Sciences Publication Activity Database

    Sochor, M.; Balík, Karel; Suchý, Tomáš; Sucharda, Zbyněk

    Vol. 47. Liberec : Technical University of Liberec, 2009 - (Marvalová, B.; Petríková, I.; Čapek, L.), s. 28-31 ISBN 978-80-7372-483-2. [Experimental Stress Analysis 2009. Sychrov (CZ), 08.06.2009-11.06.2009] R&D Projects: GA ČR(CZ) GA106/06/1576 Institutional research plan: CEZ:AV0Z30460519 Keywords : polydimethylsiloxane * aramid * hydroxyapatite Subject RIV: JI - Composite Materials

  9. Sintered composite gradient tool materials

    Directory of Open Access Journals (Sweden)

    J. Mikuła

    2008-07-01

    Full Text Available Purpose: Development of a new generation of the composite gradient tool materials with the core sintered withthe matrix obtained using the powder metallurgy of the chemical composition corresponding to the HS6-5-2 highspeedsteel reinforced with the WC and TiC type hard carbide phases with the growing portions of these phases inthe outward direction from the core to the surface.Design/methodology/approach: Powder Metallurgy, SEM, X-Ray Microanalysis.Findings: Powder metallurgy processes were used to fabricate the proposed gradient materials, i.e., compacting inthe closed die and sintering. The method of sequential pouring of the successive portions of the powder mixes intothe die was used to ensure a high ductility of the fabricated material core with the HS6-5-2 steel matrix reinforcedwith the hard WC and TiC carbides phases, so that portions of powder with the high percentage of the hard carbidesphases would form the outer layers of the prepreg.Practical implications: Employment of powder metallurgy for fabricating the steel based tool materials givesthe possibility to preserve properties characteristic of the traditional cemented carbides and with the high ductilitycharacteristic of steel, yet better than the traditional sintered high-speed steels obtained with the ASP method.Originality/value: Providing of high properties characteristic of cemented carbides with the high ductilitycharacteristic of steel can be mostly because of the possibility of ensuring the gradients of the chemicalcomposition and properties, cutting simultaneously fabrication costs thanks to savings made on the hard carbidephase, used in the tool surface layer only.

  10. Composite materials for fusion applications

    International Nuclear Information System (INIS)

    Ceramic matrix composites, CMCs, are being considered for advanced first-wall and blanket structural applications because of their high-temperature properties, low neutron activation, low density and low coefficient of expansion coupled with good thermal conductivity and corrosion behavior. This paper presents a review and analysis of the hermetic, thermal conductivity, corrosion, crack growth and radiation damage properties of CMCs. It was concluded that the leak rates of a gaseous coolant into the plasma chamber or tritium out of the blanket could exceed design criteria if matrix microcracking causes existing porosity to become interconnected. Thermal conductivities of unirradiated SiC/SiC and C/SiC materials are about 1/2 to 2/3 that of Type 316 SS whereas the thermal conductivity for C/C composites is seven times larger. The thermal stress figure-of-merit value for CMCs exceeds that of Type 316 SS for a single thermal cycle. SiC/SiC composites are very resistant to corrosion and are expected to be compatible with He or Li coolants if the O2 concentrations are maintained at the appropriate levels. CMCs exhibit subcritical crack growth at elevated temperatures and the crack velocity is a function of the corrosion conditions. The radiation stability of CMCs will depend on the stability of the fiber, microcracking of the matrix, and the effects of gaseous transmutation products on properties. 23 refs., 14 figs., 1 tab

  11. Biomineralization of Engineered Spider Silk Protein-Based Composite Materials for Bone Tissue Engineering

    Directory of Open Access Journals (Sweden)

    John G. Hardy

    2016-07-01

    Full Text Available Materials based on biodegradable polyesters, such as poly(butylene terephthalate (PBT or poly(butylene terephthalate-co-poly(alkylene glycol terephthalate (PBTAT, have potential application as pro-regenerative scaffolds for bone tissue engineering. Herein, the preparation of films composed of PBT or PBTAT and an engineered spider silk protein, (eADF4(C16, that displays multiple carboxylic acid moieties capable of binding calcium ions and facilitating their biomineralization with calcium carbonate or calcium phosphate is reported. Human mesenchymal stem cells cultured on films mineralized with calcium phosphate show enhanced levels of alkaline phosphatase activity suggesting that such composites have potential use for bone tissue engineering.

  12. New bone implant material with calcium sulfate and Ti modified hydroxyapatite

    Directory of Open Access Journals (Sweden)

    A. Ślósarczyk

    2010-11-01

    Full Text Available (TiHA to develop a novel bone cement. Results of previous studies showed that bioactive potential of titanium modified hydroxyapatite ceramics is higher than that of pure HA. Calcium sulfate hemihydrate is also considered as a safe, biocompatible material, however it has been criticized for its rapid resorption. Combination of these materials may result in new cement type material with surgical handiness and selective resorption.Design/methodology/approach: TiHA was obtained by a wet method. Three compositions with different CSH:TiHA weight ratios, namely 3:2, 2:3 and 1:4 were examined. Pure CSH was used as a reference. Distilled water and Na2HPO4 solutions were applied as liquid phases. The study presents the setting time (Gillmore apparatus, phase composition (XRD, microstructure (SEM, porosity (mercury porosimetry and compressive strength of the obtained new, cement type, implant material.Findings: Initial (I and final (F setting times of the obtained cements differed in the range of 2-16 min (I and 4-75 min (F. The phase composition of the hardened cement bodies characterized by XRD method revealed the presence of calcium sulfate dihydrate (CSD and hydroxyapatite. Scanning electron microscopy images show excellent bonding between needle-like CSD crystals and apatitic phase. Porosity of the final samples varied from 49 to 59% with pore size diameter from 5 nm to 3.0 μm. Compressive strength of the samples differed in the range of 3.81-7.58 MPa.Research limitations/implications: The obtained results suggest that CSH-TiHA cements have the potential to be applied in bone substitution and for delivery of drugs. Bioactivity and biodegradation of the studied materials should be checked.Originality/value: According to our knowledge, these are the first studies concerning surgical handiness of bone implant materials based on calcium sufate hemihydrate and titanium doped hydroxyapatite. The cement type composites are biocompatible, shapeable and easy

  13. A chemical activity evaluation of two dental calcium silicate-based materials

    Directory of Open Access Journals (Sweden)

    Chalas Renata

    2015-06-01

    Full Text Available Calcium silicate-based materials are interesting products widely used in dentistry. The study was designed to compare the chemical reaction between analyzed two preparates and dentin during cavity lining. In our work, dentinal discs were prepared from human extracted teeth filled with Biodentine and MTA+. The samples were then analyzed by way of SEM, EDS and Raman spectroscopy. The obtained results revealed differences in elemental composition between both materials. Biodentine showed higher activity in contact with dentine. Moreover, the interfacial layer in the tooth filled by Biodentine was wider than that in the tooth filled with MTA+. The applied methods of analysis confirmed that both materials have a bioactive potential which is a promising ability.

  14. Injectable calcium phosphate cement and fibrin sealant recombined human bone morphogenetic protein-2 composite in vertebroplasty: an animal study

    OpenAIRE

    Qian, Guang; Dong, Youhai; Yang, Wencheng; Wang, Minghai

    2012-01-01

    Polymethylmethacrylate (PMMA) is currently the most commonly-used material, but it may induce adjacent vertebral fracture due to low degradation and high strength. Our study evaluated the feasibility of injectable calcium phosphate cement (ICPC) and fibrin sealant (FS) as an injectable compound carrier of human bone morphogenetic protein-2 (rhBMP-2) in New Zealand rabbits for vertebroplasty. Results showed ICPC/FS/rhBMP-2 composites induced alkaline phosphatase most effectively at 2 and 4 wee...

  15. Tailored sequential drug release from bilayered calcium sulfate composites

    Energy Technology Data Exchange (ETDEWEB)

    Orellana, Bryan R.; Puleo, David A., E-mail: puleo@uky.edu

    2014-10-01

    The current standard for treating infected bony defects, such as those caused by periodontal disease, requires multiple time-consuming steps and often multiple procedures to fight the infection and recover lost tissue. Releasing an antibiotic followed by an osteogenic agent from a synthetic bone graft substitute could allow for a streamlined treatment, reducing the need for multiple surgeries and thereby shortening recovery time. Tailorable bilayered calcium sulfate (CS) bone graft substitutes were developed with the ability to sequentially release multiple therapeutic agents. Bilayered composite samples having a shell and core geometry were fabricated with varying amounts (1 or 10 wt.%) of metronidazole-loaded poly(lactic-co-glycolic acid) (PLGA) particles embedded in the shell and simvastatin directly loaded into either the shell, core, or both. Microcomputed tomography showed the overall layered geometry as well as the uniform distribution of PLGA within the shells. Dissolution studies demonstrated that the amount of PLGA particles (i.e., 1 vs. 10 wt.%) had a small but significant effect on the erosion rate (3% vs. 3.4%/d). Mechanical testing determined that introducing a layered geometry had a significant effect on the compressive strength, with an average reduction of 35%, but properties were comparable to those of mandibular trabecular bone. Sustained release of simvastatin directly loaded into CS demonstrated that changing the shell to core volume ratio dictates the duration of drug release from each layer. When loaded together in the shell or in separate layers, sequential release of metronidazole and simvastatin was achieved. By introducing a tunable, layered geometry capable of releasing multiple drugs, CS-based bone graft substitutes could be tailored in order to help streamline the multiple steps needed to regenerate tissue in infected defects. - Highlights: • Bilayered CS composites were fabricated as potential bone graft substitutes. • The shell

  16. Tailored sequential drug release from bilayered calcium sulfate composites

    International Nuclear Information System (INIS)

    The current standard for treating infected bony defects, such as those caused by periodontal disease, requires multiple time-consuming steps and often multiple procedures to fight the infection and recover lost tissue. Releasing an antibiotic followed by an osteogenic agent from a synthetic bone graft substitute could allow for a streamlined treatment, reducing the need for multiple surgeries and thereby shortening recovery time. Tailorable bilayered calcium sulfate (CS) bone graft substitutes were developed with the ability to sequentially release multiple therapeutic agents. Bilayered composite samples having a shell and core geometry were fabricated with varying amounts (1 or 10 wt.%) of metronidazole-loaded poly(lactic-co-glycolic acid) (PLGA) particles embedded in the shell and simvastatin directly loaded into either the shell, core, or both. Microcomputed tomography showed the overall layered geometry as well as the uniform distribution of PLGA within the shells. Dissolution studies demonstrated that the amount of PLGA particles (i.e., 1 vs. 10 wt.%) had a small but significant effect on the erosion rate (3% vs. 3.4%/d). Mechanical testing determined that introducing a layered geometry had a significant effect on the compressive strength, with an average reduction of 35%, but properties were comparable to those of mandibular trabecular bone. Sustained release of simvastatin directly loaded into CS demonstrated that changing the shell to core volume ratio dictates the duration of drug release from each layer. When loaded together in the shell or in separate layers, sequential release of metronidazole and simvastatin was achieved. By introducing a tunable, layered geometry capable of releasing multiple drugs, CS-based bone graft substitutes could be tailored in order to help streamline the multiple steps needed to regenerate tissue in infected defects. - Highlights: • Bilayered CS composites were fabricated as potential bone graft substitutes. • The shell

  17. Composites materials: the technology of future

    International Nuclear Information System (INIS)

    Composite materials have a long history of usage. Their precise beginnings are not known; however all recorded history contains references to some form of composite material. e.g. straw was used by man to strengthen mud bricks thousands of years ago. This article presents the use of advanced composites materials in aircraft and space industry. Its brief history, use in military and civil aviation, use in space program, future usage, advantages in terms of cost, weight and strength. Use of composites in unmanned aerial vehicles and problems associated with usage of composites materials are also discussed. (author)

  18. Calcium-magnesium Aluminosilicate (CMAS) Interactions with Advanced Environmental Barrier Coating Material

    Science.gov (United States)

    Wiesner, Valerie L.; Bansal, Narottam P.

    2015-01-01

    Particulates, like sand and volcanic ash, threaten the development of robust environmental barrier coatings (EBCs) that protect next-generation silicon-based ceramic matrix composite (CMC) turbine engine components from harsh combustion environments during service. The siliceous particulates transform into molten glassy deposits of calcium-magnesium aluminosilicate (CMAS) when ingested by an aircraft engine operating at temperatures above 1200C. In this study, a sample of desert sand was melted into CMAS glass to evaluate high-temperature interactions between the sand glass and an advanced EBC material. Desert sand glass was added to the surface of hot-pressed EBC substrates, which were then heated in air at temperatures ranging from 1200C to 1500C. Scanning electron microscopy and X-ray energy-dispersive spectroscopy were used to evaluate microstructure and phase compositions of specimens and the CMASEBC interface after heat treatments.

  19. 磷酸钙骨水泥/骨形态发生蛋白复合人工骨的生物相容性%Biocompatibility of calcium phosphate cement/BMP composite as bone graft material

    Institute of Scientific and Technical Information of China (English)

    孙明林; 胡蕴玉; 贾新斌; 李丹; 刘忠湘; 朱德生

    2001-01-01

    AIM To construct CPC/BMP composite by combining CPC with BMP, and to detect their biocompatibity. METHODS The toxicity, pyrogen, hemolytic activities and immunogen were detected by means of animal test, cell culture, hemolysis test and histochemical technique. RESULTS The composites were found no toxicity and no pyrogen by animal test, no hemolytic activities and couldn't influence the coagulate of blood in vitro. When the materials were grafted into the muscle pounches in the thigh of mice or rabbits, no obvious specific antibodies produced were detected in serum by ELISA, nor were significant immune reaction of foreign body observed by histochemistry technique. The composites were also testified no cytotoxicity in vitor for the proliferation of cultured cells couldn' be inhibited. CONCLUSION The CPC/BMP composite might have good biocompatibility and be safe for clinical use.%目的将自行合成的磷酸钙骨水泥(CPC)作为载体与BMP复合成人工骨,检测其生物相容性. 方法制备CPC/BMP及CPC骨块,通过体外实验、细胞培养、动物实验等方法观察其毒性、免疫原性、对血液系统的影响等生物相容性指标. 结果动物实验表明材料属无毒级,不含致热原,体外试验不引起溶血反应,对凝血功能无明显影响. 植入兔或小鼠肌袋内未检测出特异性抗体. 组织学检查未见免疫排斥反应,对肌肉无刺激作用.对体外培养的细胞增殖没有明显抑制作用.结论材料有较好的生物相容性,临床使用安全.

  20. Composites Associated with Pulp-Protection Material: Color-Stability Analysis after Accelerated Artificial Aging

    OpenAIRE

    Cruvinel, Diogo Rodrigues; Garcia, Lucas da Fonseca Roberti; Simonides CONSANI; de Carvalho Panzeri Pires-de-Souza, Fernanda

    2010-01-01

    Objectives: This study assessed the color stability of two composites associated with two pulp protectors submitted to accelerated artificial aging (AAA). Methods: 60 test specimens were made with 0.5 mm of protection material (calcium hydroxide - CH or glass ionomer cement - GIC) and 2.5 mm of restoration material (Concept or QuixFil) and divided into 3 groups (n=10) according to the type of protection material/composite, and the control group (no protection). After polishing, color readings...

  1. Flywheel materials technology: design data manual for composite materials

    Energy Technology Data Exchange (ETDEWEB)

    Hahn, H.T.; Hwang, D.G.; Cheng, H.C.; Lo, S.Y.

    1981-07-01

    Compiled in this manual are data on thermomechanical properties of unidirectional composites. The data were taken from open literature and government reports. The primary objective of this manual is to provide the material property data necessary for design of flywheels using modern composite materials. However, the manual will be helpful for any design with composites where structural performance is a major concern. Some preliminary information necessary for an effective use of this manual is given. The characterization of strength and fatigue properties and the hygrothermal properties of composite materials are described briefly. Material properties according to the type of composite are presented. Listed for each composite system is information on constituent materials, cure cycle, preconditioning, test environment, sources of data, and test methods used. The material properties include elastic moduli, strengths, fatigue properties, and hygrothermal properties.

  2. Preparation of poly(lactic acid) composite hollow spheres containing calcium carbonates.

    Science.gov (United States)

    Maeda, Hirotaka; Kasuga, Toshihiro

    2006-07-01

    Poly(lactic acid) composite hollow spheres containing calcium carbonate were prepared by oil-in-water emulsion evaporation to develop injectable bone substitutes incorporated with cells. The spheres were approximately 1.2mm in diameter and had a shell with a thickness in the range of 50-150microm. The hollow in the spheres was presumed to be formed by CO(2) gas generated by the decomposition of vaterite used as a starting material. An open channel approximately 800microm in diameter was formed in the spheres by chemical etching utilizing the rapid dissolution of poly(lactic acid) at the thin portion of the shell. Cells could migrate into the hollow spheres through the open channel and attach to the inner surface. PMID:16765880

  3. Preparation of TiO2 nanotubes/mesoporous calcium silicate composites with controllable drug release.

    Science.gov (United States)

    Xie, Chunling; Li, Ping; Liu, Yan; Luo, Fei; Xiao, Xiufeng

    2016-10-01

    Nanotube structures such as TiO2 nanotube (TNT) arrays produced by self-ordering electrochemical anodization have been extensively explored for drug delivery applications. In this study, we presented a new implantable drug delivery system that combined mesoporous calcium silicate coating with nanotube structures to achieve a controllable drug release of water soluble and antiphlogistic drug loxoprofen sodium. The results showed that the TiO2 nanotubes/mesoporous calcium silicate composites were successfully fabricated by a simple template method and the deposition of mesoporous calcium silicate increased with the soaking time. Moreover, the rate of deposition of biological mesoporous calcium silicate on amorphous TNTs was better than that on anatase TNTs. Further, zinc-incorporated mesoporous calcium silicate coating, produced by adding a certain concentration of zinc nitrate into the soaking system, displayed improved chemical stability. A significant improvement in the drug release characteristics with reduced burst release and sustained release was demonstrated. PMID:27287140

  4. Characterization of a biodegradable coralline hydroxyapatite/calcium carbonate composite and its clinical implementation

    International Nuclear Information System (INIS)

    A partially converted, biodegradable coralline hydroxyapatite/calcium carbonate (CHACC) composite comprising a coral calcium carbonate scaffold enveloped by a thin layer of hydroxyapatite was used in the present study. The CHACC was characterized using powder x-ray diffraction, scanning electron microscopy and energy dispersive x-ray spectroscopy. The ability of the CHACC to promote conductive osteogenesis was assessed in vitro using human mesenchymal stem cells (hMSCs) and in vivo using an immunodeficient mouse model. The clinical performance of CHACC as a bone substitute to fill voids caused by excision of bone tumours was also observed in 16 patients. The CHACC was found to consist of two overlapping layers both morphologically and chemically. Hydroxyapatite formed a thin layer of nanocrystals on the surface and a thick rough crystal layer of around 30 µm in thickness enveloping the rock-like core calcium carbonate exoskeletal architecture. hMSCs cultured on CHACC in osteogenic medium demonstrated significant osteogenic differentiation. After subcutaneous implantation of CHACC incorporating osteogenically differentiated hMSCs and an anti-resorptive agent, risedronate, into an immunodeficient mouse model, bone formation was observed on the surface of the implants. Clinical application of CHACC alone in 16 patients for bone augmentation after tumour removal showed that after implantation, visible callus formation was observed at one month and clinical bone healing achieved at four months. The majority of the implanted CHACC was degraded in 18–24 months. In conclusion, CHACC appears to be an excellent biodegradable bone graft material. It biointegrates with the host, is osteoconductive, biodegradable and can be an attractive alternative to autogenous grafts. (paper)

  5. In vitro surface reaction layer formation and dissolution of calcium phosphate cement-bioactive glass composites

    Energy Technology Data Exchange (ETDEWEB)

    Liu Changsheng [Key Laboratory for Ultrafine Materials of Ministry of Education, and Engineering Research Center for Biomedical Materials of Ministry of Education, East China University of Science and Technology, Shanghai 200237 (China); Chen, C.-W.; Ducheyne, Paul [Center for Bioactive Materials and Tissue Engineering, Department of Bioengineering, University of Pennsylvania, Philadelphia, PA 19104 (United States)], E-mail: liucs@ecust.edu.cn, E-mail: ducheyne@seas.upenn.edu

    2008-09-01

    Composites of hydrated calcium phosphate cement (CPC) and bioactive glass (BG) containing Si were immersed in vitro to study the effect of chemical composition on surface reaction layer formation and dissolution/precipitation behavior. The solutions used were 0.05 M tris hydroxymethyl aminomethane/HCl (tris buffer), tris buffer supplemented with plasma electrolyte (TE) with pH 7.4 at 37 deg. C, and this solution complemented with 10% newborn bovine serum (TES). The post-immersion solutions were analyzed for changes in Ca, PO{sub 4} and Si concentrations. The reacted surfaces were analyzed using Fourier transform infrared (FTIR), and scanning electron microscopy with energy dispersive x-ray analysis. The sample weight variations after immersion were also determined. The results showed that the composition of the bioactive composite CPCs greatly affected their behavior in solution and the formation of apatite bioactive surface reaction layers. After immersion in the TE solution, Ca ions were taken up by all samples during the entire immersion duration. Initially, the P ion concentration increased sharply, and then decreased. This reaction pattern reveals the formation of an amorphous calcium phosphate layer on the surface of these composite CPCs. FTIR revealed that the layer was, in fact, poorly crystallized Ca-deficient carbonate apatite. The thickness of the layer was 12-14 {mu}m and it was composed of rod-like apatite with directional arrangement. For immersion in the TES solution, the Ca and Si ion concentrations showed a similar behavior to that in TE, but the release rate of Si ions was higher. FTIR revealed that after TES immersion, not only did the typical, poorly crystallized, Ca-deficient carbonated apatite form, as it did in TE, but also the serum proteins co-adsorbed on the surface and thereby affected the surface reaction layer formation. A thinner apatite layer was formed and was composed of a micro-porous layer comprising rounded particles in a glue

  6. Synthesis, characterization, and mineralization of polyamide-6/calcium lactate composite nanofibers for bone tissue engineering.

    Science.gov (United States)

    Pant, Hem Raj; Risal, Prabodh; Park, Chan Hee; Tijing, Leonard D; Jeong, Yeon Jun; Kim, Cheol Sang

    2013-02-01

    Polyamide-6 nanofibers containing calcium lactate (CL) on their surface were prepared by neutralization of lactic acid (LA) in core-shell structured polyamide-6/LA electrospun fibers. First, simple blending of LA with polyamide-6 solution was used for electrospinning which interestingly formed a thin LA layer around polyamide-6 nanofibers (core-shell structure) and then subsequent conversion of this LA into calcium lactate via neutralization using calcium base. FE-SEM and TEM images revealed that plasticizer capacity of LA led the formation of point-bonded structure due to the formation of shell layer of LA and core of polyamide-6. The bone formation ability of polyamide-6/calcium lactate composite fibers was evaluated by incubating in biomimetic simulated body fluid (SBF). The SBF incubation test confirmed the faster deposition of large amount of calcium phosphate around the composite polyamide-6/calcium lactate fibers compared to pristine polyamide-6. This study demonstrated a simple post electrospinning calcium compound coating technique of polymeric nanofibers for enhancing the bone biocompatibility of polyamide-6 fibers. PMID:23006560

  7. Composite materials with integrated embedded sensing networks

    OpenAIRE

    Schaaf, Kristin Leigh

    2008-01-01

    The increasing demand for in-service structural health monitoring has stimulated efforts to integrate self and environmental sensing capabilities into materials and structures. The present work is directed towards the development of a new means of fabricating composites that allows for integrating a high density of small, advanced sensors into a laminated composite in a way that enables sensing without compromising the structural integrity of the host composite material. This work presents ef...

  8. Flame-retardant composite materials

    Science.gov (United States)

    Kourtides, Demetrius A.

    1991-01-01

    The properties of eight different graphite composite panels fabricated using four different resin matrices and two types of graphite reinforcement are described. The resin matrices included: VPSP/BMI, a blend of vinylpolystyryl pyridine and bismaleimide; BMI, a bismaleimide; and phenolic and PSP, a polystyryl pyridine. The graphite fiber used was AS-4 in the form of either tape or fabric. The properties of these composites were compared with epoxy composites. It was determined that VPSP/BMI with the graphite tape was the optimum design giving the lowest heat release rate.

  9. Composites and blends from biobased materials

    Energy Technology Data Exchange (ETDEWEB)

    Kelley, S.S. [National Renewable Energy Laboratory, Golden, CO (United States)

    1995-05-01

    The program is focused on the development of composites and blends from biobased materials to use as membranes, high value plastics, and lightweight composites. Biobased materials include: cellulose derivative microporous materials, cellulose derivative copolymers, and cellulose derivative blends. This year`s research focused on developing an improved understanding of the molecular features that cellulose based materials with improved properties for gas separation applications. Novel cellulose ester membrane composites have been developed and are being evaluated under a collaborative research agreement with Dow Chemicals Company.

  10. Effects of calcium phosphate composition in sputter coatings on in vitro and in vivo performance.

    Science.gov (United States)

    Urquia Edreira, Eva R; Wolke, Joop G C; Aldosari, Abdullah AlFarraj; Al-Johany, Sulieman S; Anil, Sukumaran; Jansen, John A; van den Beucken, Jeroen J J P

    2015-01-01

    Calcium phosphate (CaP) ceramic coatings have been used to enhance the biocompatibility and osteoconductive properties of metallic implants. The chemical composition of these ceramic coatings is an important parameter, which can influence the final bone performance of the implant. In this study, the effect of phase composition of CaP-sputtered coatings was investigated on in vitro dissolution behavior and in vivo bone response. Coatings were prepared by a radio frequency (RF) magnetron sputtering technique; three types of CaP target materials were used to obtain coatings with different stoichiometry and calcium to phosphate ratios (hydroxyapatite (HA), α-tricalciumphosphate (α-TCP), and tetracalciumphosphate (TTCP)) were compared with non-coated titanium controls. The applied ceramic coatings were characterized by X-ray diffraction, Fourier transform infrared spectroscopy, scanning electron microscopy, and inductively coupled plasma optical emission spectroscopy. The in vitro dissolution/precipitation of the CaP coatings was evaluated using immersion tests in simulated body fluid (SBF). To mimic the in vivo situation, identical CaP coatings were also evaluated in a femoral condyle rabbit model. TCPH and TTCPH showed morphological changes during 4-week immersion in SBF. The results of bone implant contact (BIC) and peri-implant bone volume (BV) showed a similar response for all experimental coatings. An apparent increase in tartrate resistant acid phosphatase (TRAP) positive staining was observed in the peri-implant region with decreasing coating stability. In conclusion, the experimental groups showed different coating properties when tested in vitro and an apparent increase in bone remodeling with increasing coating dissolution in vivo. PMID:24659523

  11. Fabrication and materials properties of high-density polyethylene (HDPE)/biphasic calcium phosphate (BCP) hybrid bone plates

    International Nuclear Information System (INIS)

    Biphasic calcium phosphate-reinforced high-density polyethylene (BCP/HDPE) hybrid composite is a new orthopedic biomaterial, which was made to simulate a natural bone composition. Calcium phosphate systems and HDPE hybrid composites have been used in biomedical applications without any inflammatory response. Differences in natural bone of both materials have motivated the use of coupling agents to improve their interfacial interfacial interactions. The composites were prepared using medical grade BCP powder and granular polyethylene. This material was produced by replacing the mineral component and collagen soft tissue of the bone with BCP and HDPE, respectively. As expected, increased volume fraction of either reinforcement type over 0 ∼ 50 vol.% resulted in a increased Vickers hardness and Young's modulus. Thus, BCP particle-reinforced HDPE composites possessed improved material and mechanical properties. BCP particles-reinforced composites were anisotropic due to an alignment of the particles in the matrix during a processing. On the other hand, bending and tensile strength was dramatically changed in the matrix. To change the material and mechanical properties of HDPE/BCP composites, the process of a blending was used, and its effect on the microstructure and mechanical proprieties of HDPE/BCP composites were investigated by means of FT-IR/ATR spectroscopy, XRD, FE-SEM, Vickers Hardness Testing Machine, Universal Testing Machine, Mercury Porosimeter and Ultrasonic Flaw Detector at room temperature. For the evaluation of the cell viability and proliferation onto the external surface of HDPE/BCP hybrid plates with a HaCaT cell line, which is a multipotent cell line able to differentiate towards different phenotypes under the action of biological factors, has been evaluated with in vitro studies and quantified by colormetric assays. These findings indicate that the HDPE/BCP hybrid plates are biocompatible and non-toxic

  12. Friction material composites copper-metal-free material design perspective

    CERN Document Server

    Sundarkrishnaa, K L

    2015-01-01

    This book examines material composites used in connection with brake friction, their design and safety. To aid in understanding, the essentials of friction are explained. This second edition was extended to include friction material composites without copper, as they offer an environmentally friendlier option. The second edition is intended to support beginners by offering insights into the essentials of friction material composites, helping them to develop a broader understanding of brake friction materials. Friction materials find wide-ranging applications in household and industrial appliances, brake pads for automotive applications, rail brake friction pads and composition brake blocks. This second edition is an introductory volume to a set of related books, and is based on the author’s experience and expertise with various material manufacturers, brake manufacturers, vehicle manufacturers, researchers and testing labs around the world with which the author has been associated for the past 28 years.

  13. Variational Asymptotic Micromechanics Modeling of Composite Materials

    OpenAIRE

    Tang, Tian

    2008-01-01

    The issue of accurately determining the effective properties of composite materials has received the attention of numerous researchers in the last few decades and continues to be in the forefront of material research. Micromechanics models have been proven to be very useful tools for design and analysis of composite materials. In the present work, a versatile micromechanics modeling framework, namely, the Variational Asymptotic Method for Unit Cell Homogenization (VAMUCH), has been invented a...

  14. Composite Materials for Low-Temperature Applications

    Science.gov (United States)

    2008-01-01

    Composite materials with improved thermal conductivity and good mechanical strength properties should allow for the design and construction of more thermally efficient components (such as pipes and valves) for use in fluid-processing systems. These materials should have wide application in any number of systems, including ground support equipment (GSE), lunar systems, and flight hardware that need reduced heat transfer. Researchers from the Polymer Science and Technology Laboratory and the Cryogenics Laboratory at Kennedy Space Center were able to develop a new series of composite materials that can meet NASA's needs for lightweight materials/composites for use in fluid systems and also expand the plastic-additive markets. With respect to thermal conductivity and physical properties, these materials are excellent alternatives to prior composite materials and can be used in the aerospace, automotive, military, electronics, food-packaging, and textile markets. One specific application of the polymeric composition is for use in tanks, pipes, valves, structural supports, and components for hot or cold fluid-processing systems where heat flow through materials is a problem to be avoided. These materials can also substitute for metals in cryogenic and other low-temperature applications. These organic/inorganic polymeric composite materials were invented with significant reduction in heat transfer properties. Decreases of 20 to 50 percent in thermal conductivity versus that of the unmodified polymer matrix were measured. These novel composite materials also maintain mechanical properties of the unmodified polymer matrix. These composite materials consist of an inorganic additive combined with a thermoplastic polymer material. The intrinsic, low thermal conductivity of the additive is imparted into the thermoplastic, resulting in a significant reduction in heat transfer over that of the base polymer itself, yet maintaining most of the polymer's original properties. Normal

  15. A novel biodegradable nicotinic acid/calcium phosphate composite coating on Mg–3Zn alloy

    International Nuclear Information System (INIS)

    A novel biodegradable composite coating is prepared to reduce the biodegradation rate of Mg–3Zn alloy. The Mg–3Zn substrate is first immersed into 0.02 mol L−1 nicotinic acid (NA) solution, named as vitamin B3, to obtain a pretreatment film, and then the electrodeposition of calcium phosphate coating with ultrasonic agitation is carried out on the NA pretreatment film to obtain a NA/calcium phosphate composite coating. Surface morphology is observed by scanning electron microscopy (SEM). Chemical composition is determined by X-ray diffraction (XRD) and EDX. Protection property of the coatings is evaluated by electrochemical tests. The biodegradable behavior is investigated by immersion tests. The results indicate that a thin but compact bottom layer can be obtained by NA pretreatment. The electrodeposition calcium phosphate coating consists of many flake particles and ultrasonic agitation can greatly improve the compactness of the coating. The composite coating is biodegradable and can reduce the biodegradation rate of Mg alloys in stimulated body fluid (SBF) for twenty times. The biodegradation process of the composite coating can be attributed to the gradual dissolution of the flake particles into chippings. - Highlights: ► NA/calcium phosphate composite coating is prepared to protect Mg–3Zn alloy implant. ► Nicotinic acid (vitamin B3) is available to obtain a protective bottom film. ► Ultrasonic agitation greatly improves the compactness of calcium phosphate coating. ► The composite coating can reduce the biodegradation rate of Mg–3Zn twenty times. ► The composite coating is biodegraded by the dissolution of flakes into chippings.

  16. A novel biodegradable nicotinic acid/calcium phosphate composite coating on Mg-3Zn alloy

    Energy Technology Data Exchange (ETDEWEB)

    Song, Yingwei, E-mail: ywsong@imr.ac.cn; Shan, Dayong; Han, En-Hou

    2013-01-01

    A novel biodegradable composite coating is prepared to reduce the biodegradation rate of Mg-3Zn alloy. The Mg-3Zn substrate is first immersed into 0.02 mol L{sup -1} nicotinic acid (NA) solution, named as vitamin B{sub 3}, to obtain a pretreatment film, and then the electrodeposition of calcium phosphate coating with ultrasonic agitation is carried out on the NA pretreatment film to obtain a NA/calcium phosphate composite coating. Surface morphology is observed by scanning electron microscopy (SEM). Chemical composition is determined by X-ray diffraction (XRD) and EDX. Protection property of the coatings is evaluated by electrochemical tests. The biodegradable behavior is investigated by immersion tests. The results indicate that a thin but compact bottom layer can be obtained by NA pretreatment. The electrodeposition calcium phosphate coating consists of many flake particles and ultrasonic agitation can greatly improve the compactness of the coating. The composite coating is biodegradable and can reduce the biodegradation rate of Mg alloys in stimulated body fluid (SBF) for twenty times. The biodegradation process of the composite coating can be attributed to the gradual dissolution of the flake particles into chippings. - Highlights: Black-Right-Pointing-Pointer NA/calcium phosphate composite coating is prepared to protect Mg-3Zn alloy implant. Black-Right-Pointing-Pointer Nicotinic acid (vitamin B{sub 3}) is available to obtain a protective bottom film. Black-Right-Pointing-Pointer Ultrasonic agitation greatly improves the compactness of calcium phosphate coating. Black-Right-Pointing-Pointer The composite coating can reduce the biodegradation rate of Mg-3Zn twenty times. Black-Right-Pointing-Pointer The composite coating is biodegraded by the dissolution of flakes into chippings.

  17. Environment Friendly Composite Materials: Biocomposites and Green Composites

    OpenAIRE

    B. C. Mitra

    2014-01-01

    Biocomposites can supplement and eventually replace petroleum-based composite materials in several applications. Several critical issues related to bio-fiber surface treatments is to make it a more suitable matrix for composite application and promising techniques need to be solved to design biocomposite of interest. The main motivation for developing biocomposites has been and still is to create a new generation of fiber reinforced plastics material competitive with glass fiber reinforced on...

  18. Biomedical composites materials, manufacturing and engineering

    CERN Document Server

    Davim, J Paulo

    2013-01-01

    Composite materials are engineered materials, made from two or more constituents with significantly different physical or chemical properties which remain separate on a macroscopic level within the finished structure. Due to their special mechanical and physical properties they have the potential to replace conventional materials in various fields such as the biomedical industry.

  19. Materials research at Stanford University. [composite materials, crystal structure, acoustics

    Science.gov (United States)

    1975-01-01

    Research activity related to the science of materials is described. The following areas are included: elastic and thermal properties of composite materials, acoustic waves and devices, amorphous materials, crystal structure, synthesis of metal-metal bonds, interactions of solids with solutions, electrochemistry, fatigue damage, superconductivity and molecular physics and phase transition kinetics.

  20. Fibrous and textile materials for composite applications

    CERN Document Server

    Fangueiro, Raul

    2016-01-01

    This book focuses on the fibers and textiles used in composite materials. It presents both existing technologies currently used in commercial applications and the latest advanced research and developments. It also discusses the different fiber forms and architectures, such as short fibers, unidirectional tows, directionally oriented structures or advanced 2D- and 3D-textile structures that are used in composite materials. In addition, it examines various synthetic, natural and metallic fibers that are used to reinforce polymeric, cementitious and metallic matrices, as well as fiber properties, special functionalities, manufacturing processes, and composite processing and properties. Two entire chapters are dedicated to advanced nanofiber and nanotube reinforced composite materials. The book goes on to highlight different surface treatments and finishes that are applied to improve fiber/matrix interfaces and other essential composite properties. Although a great deal of information about fibers and textile str...

  1. New composite materials to metal sorption

    International Nuclear Information System (INIS)

    Complexing-active polymers are promising substances for detoxication of radioactive elements from the polluted soils and natural waters. Tis work is devoted to searching of new polymeric compositions for detoxication of soils and waters from heavy metals. Three systems (azole-carboxylic polyampholytes, polymer-polymer complexes of poly(1-vinylimidazole) (PVI), Ai- and Al-based organo/inorganic composites) were discussed. Sorption properties of new composites were studied using Cu2+ ions as an example. The sorption equilibrium range time is equals to 20-60 min, sorption capacity attains 280 mg/g. The most effective sorbents are composites on the basis of PVI, poly(4-vinylpyridine) decrease sorption capacity due to hydrophobia of this polymer. Thus, composites on the basis of nitrogen-containing polymers are promising systems for heavy materials sorption. Introduction of Si-, Al-hydroxides into composites allows to decrease cost of the materials and increase their nature-compatibility

  2. Monolithic calcium phosphate/poly(lactic acid) composite versus calcium phosphate-coated poly(lactic acid) for support of osteogenic differentiation of human mesenchymal stromal cells.

    Science.gov (United States)

    Tahmasebi Birgani, Zeinab; van Blitterswijk, Clemens A; Habibovic, Pamela

    2016-03-01

    Calcium phosphates (CaPs), extensively used synthetic bone graft substitutes, are often combined with other materials with the aim to overcome issues related to poor mechanical properties of most CaP ceramics. Thin ceramic coatings on metallic implants and polymer-ceramic composites are examples of such hybrid materials. Both the properties of the CaP used and the method of incorporation into a hybrid structure are determinant for the bioactivity of the final construct. In the present study, a monolithic composite comprising nano-sized CaP and poly(lactic acid) (PLA) and a CaP-coated PLA were comparatively investigated for their ability to support proliferation and osteogenic differentiation of bone marrow-derived human mesenchymal stromal cells (hMSCs). Both, the PLA/CaP composite, produced using physical mixing and extrusion and CaP-coated PLA, resulting from a biomimetic coating process at near-physiological conditions, supported proliferation of hMSCs with highest rates at PLA/CaP composite. Enzymatic alkaline phosphatase activity as well as the mRNA expression of bone morphogenetic protein-2, osteopontin and osteocalcin were higher on the composite and coated polymer as compared to the PLA control, while no significant differences were observed between the two methods of combining CaP and PLA. The results of this study confirmed the importance of CaP in osteogenic differentiation while the exact properties and the method of incorporation into the hybrid material played a less prominent role. PMID:26787486

  3. Graphene-based Composite Materials

    Science.gov (United States)

    Rafiee, Mohammad Ali

    We investigated the mechanical properties, such as fracture toughness (KIc), fracture energy (GIc), ultimate tensile strength (UTS), Young¡¦s modulus (E), and fatigue crack propagation rate (FCPR) of epoxy-matrix composites with different weight fractions of carbon-based fillers, including graphene platelets (GPL), graphene nanoribbons (GNR), single-walled carbon nanotubes (SWNT), multi-walled carbon nanotubes (MWNT), and fullerenes (C60). Only ˜0.125 wt.% GPL was found to increase the KIc of the pure epoxy by ˜65% and the GIc by ˜115%. To get similar improvement, CNT and nanoparticle epoxy composites required one to two orders of magnitude greater weight fraction of nanofillers. Moreover, ˜0.125% wt.% GPL also decreased the fatigue crack propagation rate in the epoxy by ˜30-fold. The E value of 0.1 wt.% GPL/epoxy nanocomposite was ˜31% larger than the pure epoxy while there was only an increase of ˜3% for the SWNT composites. The UTS of the pristine epoxy was improved by ˜40% with GPLs in comparison with ˜14% enhancement for the MWNTs. The KIc of the GPL nanocomposite enhanced by ˜53% over the pristine epoxy compared to a ˜20% increase for the MWNT-reinforced composites. The results of the FCPR tests for the GPL nanocomposites showed a different trend. While the CNT nanocomposites were not effective enough to suppress the crack growth at high values of the stress intensity factor (DeltaK), the reverse behavior is observed for the GPL nanocomposites. The advantage of the GPLs over CNTs in terms of mechanical properties enhancement is due to their enormous specific surface area, enhanced adhesion at filler/epoxy interface (because of the wrinkled surfaces of GPLs), as well as the planar structure of the GPLs. We also show that unzipping of MWNTs into graphene nanoribbons (GNRs) enhances the load transfer effectiveness in epoxy nanocomposites. For instance, at ˜0.3 wt.% of fillers, the Young's modulus (E) of the epoxy nanocomposite with GNRs increased

  4. Composite materials with improved phyllosilicate dispersion

    Science.gov (United States)

    Chaiko, David J.

    2004-09-14

    The present invention provides phyllosilicates edge modified with anionic surfactants, composite materials made from the edge modified phyllosilicates, and methods for making the same. In various embodiments the phyllosilicates are also surface-modified with hydrophilic lipophilic balance (HLB) modifying agents, polymeric hydrotropes, and antioxidants. The invention also provides blends of edge modified phyllosilicates and semicrystalline waxes. The composite materials are made by dispersing the edge modified phyllosilicates with polymers, particularly polyolefins and elastomers.

  5. Composite, ordered material having sharp surface features

    Science.gov (United States)

    D'Urso, Brian R.; Simpson, John T.

    2006-12-19

    A composite material having sharp surface features includes a recessive phase and a protrusive phase, the recessive phase having a higher susceptibility to a preselected etchant than the protrusive phase, the composite material having an etched surface wherein the protrusive phase protrudes from the surface to form a sharp surface feature. The sharp surface features can be coated to make the surface super-hydrophobic.

  6. Fatigue and fracture research in composite materials

    Science.gov (United States)

    Obrien, T. K.

    1982-01-01

    The fatigue, fracture, and impact behavior of composite materials are investigated. Bolted and bonded joints are included. The solutions developed are generic in scope and are useful for a wide variety of structural applications. The analytical tools developed are used to demonstrate the damage tolerance, impact resistance, and useful fatigue life of structural composite components. Standard tests for screening improvements in materials and constituents are developed.

  7. HPC in Computational Micromechanics of Composite Materials

    OpenAIRE

    Blaheta, R. (Radim); Kolcun, A. (Alexej); Jakl, O. (Ondřej); Souček, K; Starý, J. (Jiří); Georgiev, J.

    2015-01-01

    By micromechanics we understand analysis of the macroscale response of materials through investigation of processes in their microstructure. Here by the macroscale, we mean the scale of applications, where we solve engineering problems involving materials. Examples could be analysis of aircraft constructions with different composite materials and analysis of rock behaviour and concrete properties in geo- and civil engineering applications. Analysis of bio-materials with many medicine...

  8. Evaluation of Calcium Phosphate Cement As a Root Canal Sealer Filling Material

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    Calcium phosphate cement for root end sealing was obtained by mixing α-tricalcium phosphate and additives with an aqueous solution of citric. Powder and liquid were mixed at a ratio of 1.25g/mL. The biocompatibility of this material was investigated primarily by subcutaneous implantation tests. Then calcium phosphate cement was used to fill three adult dogs' root canal, both calcium hydroxide paste and hydroxyapatite paste as control. The animals were killed at 4,12,20 weeks postoperatively respectively. The effects of different materials on the apical closure, restoration of periapical tissues and adaptability to the dentinal surface were examined by optical and electronic microscope. The observation at 20 weeks shows that the calcium phosphate cement has the potentialities of being a root canal sealer filling material available for pulpless teeth with open-apex and destructive periapical tissue.

  9. Preparation and characterization of bioactive and degradable composites containing ordered mesoporous calcium-magnesium silicate and poly(L-lactide)

    International Nuclear Information System (INIS)

    Highlights: • Mesoporous calcium-magnesium silicate and poly(L-lactide) composite was fabricated. • The composite has good hydrophilicity, in vitro degradation and bioactivity. • The composite could support cell attachment, proliferation and differentiation. - Abstract: Polylactide (PLA) and its copolymers have been widely used for bone tissue regeneration. In this study, a bioactive composite of ordered mesoporous calcium–magnesium silicate (m-CMS) and poly(L-lactide) (PLLA) was fabricated by melt blending method. The results indicated that the m-CMS particles were entrapped by polymer phase, and crystallinity of PLLA significantly decreased while the thermal stability of the m-CMS/PLLA composites was not obviously affected by addition of the m-CMS into PLLA. In addition, compared to PLLA, incorporation of the m-CMS into PLLA significantly improved the hydrophilicity, in vitro degradability and bioactivity (apatite-formation ability) of the m-CMS/PLLA composite, which were m-CMS content dependent. Moreover, it was found that incorporation of the m-CMS into PLLA could neutralize the acidic degradation by-products and thus compensated for the decrease of pH value. In cell culture experiments, the results showed that the composite enhanced attachment, proliferation and alkaline phosphatase activity (ALP) of MC3T3-E1 cells, which were m-CMS content dependent. The results indicated that the addition of bioactive materials to PLLA could result in a composite with improved properties of hydrophilicity, degradability, bioactivity and cytocompatibility

  10. Preparation and characterization of bioactive and degradable composites containing ordered mesoporous calcium-magnesium silicate and poly(L-lactide)

    Energy Technology Data Exchange (ETDEWEB)

    Ji, Jiajin [Key Shanghai Key Laboratory of Advanced Polymeric Materials, East China University of Science and Technology, Shanghai 200237 (China); Dong, Xieping, E-mail: jxzhyxh@163.com [Department of Orthopaedic Surgery, Jiangxi People' s Hospital, Nanchang 330006 (China); Ma, Xuhui [Polymer Science (Shenzhen) New Materials Co., Ltd., Shenzhen 518101 (China); Tang, Songchao, E-mail: schtang@ecust.edu.cn [Key Shanghai Key Laboratory of Advanced Polymeric Materials, East China University of Science and Technology, Shanghai 200237 (China); Wu, Zhaoying; Xia, Ji; Wang, Quanxiang; Wang, Yutao; Wei, Jie [Key Shanghai Key Laboratory of Advanced Polymeric Materials, East China University of Science and Technology, Shanghai 200237 (China)

    2014-10-30

    Highlights: • Mesoporous calcium-magnesium silicate and poly(L-lactide) composite was fabricated. • The composite has good hydrophilicity, in vitro degradation and bioactivity. • The composite could support cell attachment, proliferation and differentiation. - Abstract: Polylactide (PLA) and its copolymers have been widely used for bone tissue regeneration. In this study, a bioactive composite of ordered mesoporous calcium–magnesium silicate (m-CMS) and poly(L-lactide) (PLLA) was fabricated by melt blending method. The results indicated that the m-CMS particles were entrapped by polymer phase, and crystallinity of PLLA significantly decreased while the thermal stability of the m-CMS/PLLA composites was not obviously affected by addition of the m-CMS into PLLA. In addition, compared to PLLA, incorporation of the m-CMS into PLLA significantly improved the hydrophilicity, in vitro degradability and bioactivity (apatite-formation ability) of the m-CMS/PLLA composite, which were m-CMS content dependent. Moreover, it was found that incorporation of the m-CMS into PLLA could neutralize the acidic degradation by-products and thus compensated for the decrease of pH value. In cell culture experiments, the results showed that the composite enhanced attachment, proliferation and alkaline phosphatase activity (ALP) of MC3T3-E1 cells, which were m-CMS content dependent. The results indicated that the addition of bioactive materials to PLLA could result in a composite with improved properties of hydrophilicity, degradability, bioactivity and cytocompatibility.

  11. Effect of meal composition on calcium absorption: enhancing effect of carbohydrate polymers

    International Nuclear Information System (INIS)

    Meal components including fat, fiber, and carbohydrates can influence the intestinal absorption of calcium; such interactions may be of even greater importance in the presence of intestinal disease. This study compares intestinal absorption of 47CaCl2 administered in four ways: in water, within a standard meal, with a liquid formula (Ensure, Ross Laboratories, Columbus, Ohio), or with a glucose polymer solution (Frodex-15, Ross). Studies were carried out in 9 patients with ileal resection, 3 patients with jejunoileal bypass, and 14 controls. Fractional calcium absorption from water was lower in patients than in controls. Absorption was enhanced 1.5- to 5-fold when 47CaCl2 was administered with a liquid formula diet containing a glucose polymer or with the glucose polymer alone. Patients with the lowest calcium absorption from breakfast showed the greatest effect of calcium ingestion with formula or glucose polymer. These findings further emphasize the importance of meal composition on calcium absorption and provide a possible mechanism for enhancing calcium absorption in some patients with chronically impaired absorption

  12. RBS and XPS analyses of the composite calcium phosphate coatings for biomedical applications

    International Nuclear Information System (INIS)

    The calcium phosphate coatings on metallic implants are widely used for biomedical applications. The calcium phosphate coatings require mechanical strength, strong adhesion to the metallic implants, chemical stability and low dissolution into the human body fluid for stable functioning in the corrosive environment of the human body. In this study, a novel approach for improving the calcium phosphate coatings is utilized by adding trace metallic element into the coatings. We focused on teeth enamel, which is the hardest calcium phosphate tissue in the human body. Zn concentration increases exponentially from the interior to the surface of the enamel. As the Zn concentration increases, so the local hardness increases. Our previous studies suggest that Zn has influence on the hardness and other properties of enamel, calcium phosphate tissue. Calcium phosphate coatings doped with Zn was fabricated and characterized. The atomic composition and chemical state were investigated by using Rutherford backscattering spectroscopy (RBS) and X-ray photoelectron spectrometer (XPS), respectively. Scratch test was also carried out for measuring the adhesion of the coatings

  13. Development of radiation resistant organic composite materials

    International Nuclear Information System (INIS)

    Radiation resistant composite material has been developed. Stress analysis and the matrix choice were made carefully. The stress analysis reveals that the intrinsic radiation induced degradation was brought by the degradation of interlaminar shear strength. It means the preventing the degradation of interlaminar shear strength is important to develop the radiation resistant composite materials. To prevent the degradation of the interlaminar shear strength the three dimensional fabrics are used as the reinforcement and the boron free glass fibers were chosen. The possible method to develop the radiation resistant organic composites are discussed. (author)

  14. Phase transformations, microstructure formation and in vitro osteoblast response in calcium silicate/brushite cement composites.

    Science.gov (United States)

    Sopcak, T; Medvecky, L; Giretova, M; Kovalcikova, A; Stulajterova, R; Durisin, J

    2016-01-01

    Self-setting simple calcium silicate/brushite (B) biocements with various Ca/P ratios were prepared by mutual mixing of both monocalcium silicate hydrate (CSH) or β-wollastonite (woll) powders with B and the addition of 2 wt% NaH2PO4 solution as a hardening liquid. The phase composition of the final composites and the texture of the surface calcium phosphate/silica layer were controlled by the starting Ca/P ratio in composites and the pH during setting. It was verified that the presence of continuous bone-like calcium phosphate coating on the surface of the samples was not essential for in vitro osteoblast proliferation. The nanocrystalline calcium deficient hydroxyapatite and amorphous silica were found as the main setting products in composite mixtures with a Ca/P ratio close to the region of the formation of deficient hydroxyapatite-like calcium phosphates. No CSH phase with a lower Ca/Si ratio was identified after transformation. The results confirmed a small effect of the monocalcium silicate addition on the compressive strength (CS) of cements up to 30 wt% (around 20-25 MPa) and a significant rise of the value in 50 woll/B cement (65 MPa). The final setting times of the cement composites varied between 5 and 43 min depending on the P/L ratio and the type of monocalcium silicate phase in the cement mixture. 10CSH/B and 50 woll/B cements with different textures but free of both the needle-like and perpendicularly-oriented hydroxyapatite particles on the surface of the samples had low cytotoxicity. PMID:27509265

  15. Breakthroughs in Mesoporous Composite Materials

    Institute of Scientific and Technical Information of China (English)

    2012-01-01

    Mesoporous materials have attracted a great deal of attention due to their extremely high surface area, uniform and tunable pore structure (2-50nm in diameter), and have been investigated extensively since its invention. Unfortunately,their catalytic properties are far away from the expectation due to their amorphous and inert framework and poor stability. This research project is aimed at the design and synthesis of mesoporous-

  16. Analysis of changes in selected parameters of calcium and magnesium metabolism in response to diet composition and B-group vitamin supplementation in rat

    Directory of Open Access Journals (Sweden)

    Joanna Sadowska

    2010-09-01

    Full Text Available Background. The aim of the study was to investigate the effects of a diet modification and supplementation with B-group vitamins, on selected characteristics of calcium and magnesium management in rats. Material and methods. The experiment was carried out on 60 rats aged 5 months. Animals were fed two different diets. Groups I and II received clean tap water to drink, while group III had water solution of group-B vitamins. Results. Analysis of blood plasma calcium and magnesium concentrations in the studied animals did not reveal a significant effect of the analysed factors on blood plasma calcium concentration in examined rats. An increase of the plasma level of magnesium was observed with a change in the diet composition. The supplementation reduced magnesium level to those observed in animals fed a basic feed. Diet modification and supplementation exerted the influence on whole blood calcium and magnesium levels. A change in the composition of the diet and its supplementation results also in an increase in bone calcium content in males, and in an increase in bone magnesium content in females. Conclusions. Lack of changes in blood plasma calcium levels in the studied animals implies the preservation of the homeostatic mechanisms that regulate its concentration, whereas the observed significant changes in the concentration of magnesium, point to a significant effect of this factor on its metabolism. Changes in hematocrit indicator, whole blood concentrations of calcium and magnesium and the absence of changes in concentrations of these elements in blood plasma of supplemented animals may indicate that the elements move to erythrocytes, which may imply a distortion of cellular membrane and an increase in its permeability. Composition of the diet and its supplementation modified also bone calcium and magnesium concentrations in the studied rats.

  17. Concrete compositions and methods

    Science.gov (United States)

    Chen, Irvin; Lee, Patricia Tung; Patterson, Joshua

    2015-06-23

    Provided herein are compositions, methods, and systems for cementitious compositions containing calcium carbonate compositions and aggregate. The compositions find use in a variety of applications, including use in a variety of building materials and building applications.

  18. Poly(trimethylene carbonate) and biphasic calcium phosphate composites for orbital floor reconstruction: a feasibility study in sheep.

    Science.gov (United States)

    van Leeuwen, A C; Yuan, H; Passanisi, G; van der Meer, J W; de Bruijn, J D; van Kooten, T G; Grijpma, D W; Bos, R R M

    2014-01-01

    In the treatment of orbital floor fractures, bone is ideally regenerated. The materials currently used for orbital floor reconstruction do not lead to the regeneration of bone. Our objective was to render polymeric materials based on poly(trimethylene carbonate) (PTMC) osteoinductive, and to evaluate their suitability for use in orbital floor reconstruction. For this purpose, osteoinductive biphasic calcium phosphate (BCP) particles were introduced into a polymeric PTMC matrix. Composite sheets containing 50 wt% BCP particles were prepared. Also laminates with poly(D,L-lactide) (PDLLA) were prepared by compression moulding PDLLA films onto the composite sheets. After sterilisation by gamma irradiation, the sheets were used to reconstruct surgically-created orbital floor defects in sheep. The bone inducing potential of the different implants was assessed upon intramuscular implantation. The performance of the implants in orbital floor reconstruction was assessed by cone beam computed tomography (CBCT). Histological evaluation revealed that in the orbital and intramuscular implantations of BCP containing specimens, bone formation could be seen after 3 and 9 months. Analysis of the CBCT scans showed that the composite PTMC sheets and the laminated composite sheets performed well in orbital floor reconstruction. It is concluded that PTMC/BCP composites and PTMC/BCP composites laminated with PDLLA have osteoinductive properties and seem suitable for use in orbital floor reconstruction. PMID:24488822

  19. Failure and fatigue mechanisms in composite materials

    Science.gov (United States)

    Rosen, B. W.; Kulkarni, S. V.; Mclaughlin, P. V., Jr.

    1975-01-01

    A phenomenological description of microfailure under monotonic and cyclic loading is presented, emphasizing the significance of material inhomogeneity for the analysis. Failure in unnotched unidirectional laminates is reviewed for the cases of tension, compression, shear, transverse normal, and combined loads. The failure of notched composite laminates is then studied, with particular attention paid to the effect of material heterogeneity on load concentration factors in circular holes in such laminates, and a 'materials engineering' shear-lay type model is presented. The fatigue of notched composites is discussed with the application of 'mechanistic wearout' model for determining crack propagation as a function of the number of fatigue cycles.-

  20. SEPARATION OF WATER VAPORS FROM AIR BY SORPTION ON SOME COMPOSITE MATERIALS

    OpenAIRE

    OANA HAUTĂ; MARIUS SECULA; IOAN SOLOMON; IOAN MĂMĂLIGĂ

    2014-01-01

    This work presents an experimental investigation of the kinetics of water vapor sorption on two composites synthesized by impregnating activated carbon and activated alumina respectively with lithium bromide (named as MCA2 and MCC2 respectively). The obtained results showed an increase in water amount adsorbed on both composite materials. Due to different chemical natures of the host matrices, the water sorption kinetics on MCC2 is faster compared to that of MCA2. The presence of calcium chlo...

  1. Calcium Phosphate as a Key Material for Socially Responsible Tissue Engineering

    Directory of Open Access Journals (Sweden)

    Vuk Uskoković

    2016-06-01

    Full Text Available Socially responsible technologies are designed while taking into consideration the socioeconomic, geopolitical and environmental limitations of regions in which they will be implemented. In the medical context, this involves making therapeutic platforms more accessible and affordable to patients in poor regions of the world wherein a given disease is endemic. This often necessitates going against the reigning trend of making therapeutic nanoparticles ever more structurally complex and expensive. However, studies aimed at simplifying materials and formulations while maintaining the functionality and therapeutic response of their more complex counterparts seldom provoke a significant interest in the scientific community. In this review we demonstrate that such compositional simplifications are meaningful when it comes to the design of a solution for osteomyelitis, a disease that is in its natural, non-postoperative form particularly prevalent in the underdeveloped parts of the world wherein poverty, poor sanitary conditions, and chronically compromised defense lines of the immune system are the norm. We show that calcium phosphate nanoparticles, which are inexpensive to make, could be chemically designed to possess the same functionality as a hypothetic mixture additionally composed of: (a a bone growth factor; (b an antibiotic for prophylactic or anti-infective purposes; (c a bisphosphonate as an antiresorptive compound; (d a viral vector to enable the intracellular delivery of therapeutics; (e a luminescent dye; (f a radiographic component; (g an imaging contrast agent; (h a magnetic domain; and (i polymers as viscous components enabling the injectability of the material and acting as carriers for the sustained release of a drug. In particular, calcium phosphates could: (a produce tunable drug release profiles; (b take the form of viscous and injectable, self-setting pastes; (c be naturally osteo-inductive and inhibitory for osteoclastogenesis

  2. Hydration characteristics and environmental friendly performance of a cementitious material composed of calcium silicate slag.

    Science.gov (United States)

    Zhang, Na; Li, Hongxu; Zhao, Yazhao; Liu, Xiaoming

    2016-04-01

    Calcium silicate slag is an alkali leaching waste generated during the process of extracting Al2O3 from high-alumina fly ash. In this research, a cementitious material composed of calcium silicate slag was developed, and its mechanical and physical properties, hydration characteristics and environmental friendly performance were investigated. The results show that an optimal design for the cementitious material composed of calcium silicate slag was determined by the specimen CFSC7 containing 30% calcium silicate slag, 5% high-alumina fly ash, 24% blast furnace slag, 35% clinker and 6% FGD gypsum. This blended system yields excellent physical and mechanical properties, confirming the usefulness of CFSC7. The hydration products of CFSC7 are mostly amorphous C-A-S-H gel, rod-like ettringite and hexagonal-sheet Ca(OH)2 with small amount of zeolite-like minerals such as CaAl2Si2O8·4H2O and Na2Al2Si2O8·H2O. As the predominant hydration products, rod-like ettringite and amorphous C-A-S-H gel play a positive role in promoting densification of the paste structure, resulting in strength development of CFSC7 in the early hydration process. The leaching toxicity and radioactivity tests results indicate that the developed cementitious material composed of calcium silicate slag is environmentally acceptable. This study points out a promising direction for the proper utilization of calcium silicate slag in large quantities. PMID:26691955

  3. Nondestructive characterization of advanced composite materials

    International Nuclear Information System (INIS)

    A comprehensive review of nondestructive characterization (NDC) techniques and their application to metal-matrix, polymer-matrix and ceramic-matrix composites is presented. Particular attention is given to the identification of critical materials properties and defects in these advanced composites. NDC is required: (i) to detect discrete defects, such as delaminations and cracking, and (ii) to measure distributed material properties, such as density, resistivity and elastic constants. Ultrasonic and eddy-current characterization are described in detail, along with new NDC results obtained at the Aeronautical and Maritime Research Laboratory. These include a method for the determination of fibre volume fraction in continuous fibre reinforced metal-matrix composites using eddy-current NDC, and the use of eddy-current methods to complement ultrasonic testing for characterization of impact damage in graphite-epoxy laminates. Future problem areas and possible solutions in NDC of advanced composites are also discussed. 90 refs., 1 tab., 6 figs

  4. Processes for fabricating composite reinforced material

    Energy Technology Data Exchange (ETDEWEB)

    Seals, Roland D.; Ripley, Edward B.; Ludtka, Gerard M.

    2015-11-24

    A family of materials wherein nanostructures and/or nanotubes are incorporated into a multi-component material arrangement, such as a metallic or ceramic alloy or composite/aggregate, producing a new material or metallic/ceramic alloy. The new material has significantly increased strength, up to several thousands of times normal and perhaps substantially more, as well as significantly decreased weight. The new materials may be manufactured into a component where the nanostructure or nanostructure reinforcement is incorporated into the bulk and/or matrix material, or as a coating where the nanostructure or nanostructure reinforcement is incorporated into the coating or surface of a "normal" substrate material. The nanostructures are incorporated into the material structure either randomly or aligned, within grains, or along or across grain boundaries.

  5. Health monitoring method for composite materials

    Science.gov (United States)

    Watkins, Jr., Kenneth S.; Morris, Shelby J.

    2011-04-12

    An in-situ method for monitoring the health of a composite component utilizes a condition sensor made of electrically conductive particles dispersed in a polymeric matrix. The sensor is bonded or otherwise formed on the matrix surface of the composite material. Age-related shrinkage of the sensor matrix results in a decrease in the resistivity of the condition sensor. Correlation of measured sensor resistivity with data from aged specimens allows indirect determination of mechanical damage and remaining age of the composite component.

  6. Calcium phosphate coating on magnesium alloy by biomimetic method :Investigation of morphology ,composition and formation process

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    Magnesium alloy has similar mechanical properties with natural bone and can degrade via corrosion in the electrolytic environment of the human body.Calcium phosphate has been proven to possess bioactivity and bone inductivity.In order to integrate both advantages,calcium phosphate coating was fabricated on magnesium alloy by a biomimetic method.Supersaturated calcification solutions (SCSs) with different Ca/P ratio and C1- concentration were used as mimetic solutions.The morphology,composition and formation process of the coating were studied with scanning electron microscopy (SEM),energy dispersive spectrometer (EDS),Fourier transformed infrared spectroscopy (FTIR) and X-ray diffraction (XRD).The results show that a uniform calcium phosphate coating was observed on magnesium alloy,the properties of which could be adjusted by the SCSs with different Ca/P ratio.The formation process of the coating was explored by immersing magnesium alloy in SCSs with different Cl- concentration which could adjust the hydrogen production.According to SEM results,the hydrogen bubbles were associated with the formation of grass-like and flower-like coating morphologies.In conclusion,the biomimetic method was effective to form calcium phosphate coating on magnesium alloy and the morphology and composition of the coating could be accommodated by the Ca/P ratio and Cl- concentration in SCSs.

  7. The use of thermovision technique to estimate the properties of highly filled polyolefins composites with calcium carbonate

    International Nuclear Information System (INIS)

    The aim of this work was to determine the possibility of thermovision technique usage for estimating thermal properties of ternary highly filled composites (PE-MD/iPP/CaCO3) and polymer blends (PE-MD/iPP) during mechanical measurements. The ternary, polyolefin based composites that contained the following amounts of calcium carbonate: 48, 56, and 64 wt % were studied. All materials were applying under tensile cyclic loads (x1, x5, x10, x20, x50, x100, x500, x1000). Simultaneously, a fully radiometric recording, using a TESTO infrared camera, was created. After the fatigue process, all samples were subjected to static tensile test and the maximum temperature at break was also recorded. The temperature values were analyzed in a function of cyclic loads and the filler content. The changes in the Young’s modulus values were also investigated

  8. Effect of precipitated calcium carbonate--Cellulose nanofibrils composite filler on paper properties.

    Science.gov (United States)

    He, Ming; Cho, Byoung-Uk; Won, Jong Myoung

    2016-01-20

    A new concept of composite filler was developed by using cellulose nanofibrils (CNF), precipitated calcium carbonate (PCC) and cationic starch (C-starch). In this study, cellulose nanofibrils were utilized in two different ways: a PCC-CNF composite filler and a papermaking additive in sheet forming. The aim was to elucidate their effects on flocculation, filler retention and the strength and optical properties of handsheets. The highest filler retention was obtained by using the PCC-CNF composite filler in paper sheets. The paper filled with the composite fillers had much higher bursting and tensile strengths than conventional PCC loading. It was also found that the paper prepared with PCC-CNF composite fillers became denser with increasing the filler content of paper. PMID:26572417

  9. Preparation of Laminin-apatite-polymer Composites Using Metastable Calcium Phosphate Solutions

    Institute of Scientific and Technical Information of China (English)

    2005-01-01

    A synthetic polymer with a laminin-apatite composite layer on its surface would be useful as a percutaneous device. The preparation of such a composite was attempted in the present study using poly ( ethylene terephthalate ) (PET) and polyethylene ( PE ) as the synthetic polymer. PET and PE plates and those pretreated with an oxygen plasma were alternately dipped in calcium and phosphate ion solutions, and then immersed in a metastable ealcium phosphate solution supplemented with laminin ( LCP solution ). The PET and PE plates pretreated with an oxygen plasma formed a uniform and continuous layer of a laminin- apatite composite on their surfaces. In contrast, the PET and PE plates that had not been pretreated with an oxygen plasma did not form a continuous layer of a laminin-apatite composite on their surfaces. The hydrophilic functional groups on the PET and PE surfaces introduced by the plasma treatment were responsible for the successful laminin-apatite composite coating.

  10. Experimental and Modeling Study of the Turning Process of PA 6/Nano Calcium Carbonate Composite

    OpenAIRE

    Mehdi Haghi; Reza Farshbaf Zinati; Mohammad Reza Razfar

    2013-01-01

    Nowadays, polymeric nanocomposites have emerged as a new material class with rapidly growing use in industrial products because of good mechanical, thermal, and physical properties. Recently, the requirement of the direct machining of these materials has increased due to the production of the most of them by extrusion method in simple cross section and the increased demand for personalized products. In this work, the effect of turning parameters (cutting speed and feed) and nano calcium carbo...

  11. Composite materials for rail transit systems

    Science.gov (United States)

    Griffin, O. Hayden, Jr.; Guerdal, Zafer; Herakovich, Carl T.

    1987-01-01

    The potential is explored for using composite materials in urban mass transit systems. The emphasis was to identify specific advantages of composite materials in order to determine their actual and potential usage for carbody and guideway structure applications. The literature was reviewed, contacts were made with major domestic system operators, designers, and builders, and an analysis was made of potential composite application to railcar construction. Composites were found to be in use throughout the transit industry, usually in secondary or auxiliary applications such as car interior and nonstructural exterior panels. More recently, considerable activity has been initiated in the area of using composites in the load bearing elements of civil engineering structures such as highway bridges. It is believed that new and improved manufacturing refinements in pultrusion and filament winding will permit the production of beam sections which can be used in guideway structures. The inherent corrosion resistance and low maintenance characteristics of composites should result in lowered maintenance costs over a prolonged life of the structure.

  12. Composite materials for wind power turbine blades

    DEFF Research Database (Denmark)

    Brøndsted, P.; Lilholt, H.; Lystrup, Aa.

    2005-01-01

    Renewable energy resources, of which wind energy is prominent, are part of the solution to the global energy problem. Wind turbine and the rotorblade concepts are reviewed, and loadings by wind and gravity as important factors for the fatigue performance of the materials are considered. Wood and...... composites are discussed as candidates for rotorblades. The fibers and matrices for composites are described, and their high stiffness, low density, and good fatigue performance are emphasized. Manufacturing technologies for composites are presented and evaluated with respect to advantages, problems, and...... procedures for documentation of properties are reviewed, and fatigue loading histories are discussed, together with methods for data handling and statistical analysis of (large) amounts of test data. Future challenges for materials in the field of wind turbines are presented, with a focus on thermoplastic...

  13. Porphyrin Composite Materials for Fullerene Separation

    Czech Academy of Sciences Publication Activity Database

    Šabata, Stanislav; Kuncová, Gabriela; Hetflejš, Jiří; Lhoták, P.; Slavíček, J.

    - : -, 2011, 64 /P9/. ISBN N. [Zing Nanomaterials Conference 2011. Xcaret (MX), 28.11.2011-02.12.2011] R&D Projects: GA ČR GA203/09/0691 Institutional research plan: CEZ:AV0Z40720504 Keywords : silica gel * composite materials * porphyrin Subject RIV: CC - Organic Chemistry

  14. Calcium flouride (CaF2) from oyster shell as a raw material for thermoluminescence dosimeter

    International Nuclear Information System (INIS)

    This study aims to develop a thermoluminescence dosimeter raw material made of calcium fluoride from locally available seashells that is suitable for personal radiation monitoring. Oyster shells were collected and grounded as powder samples and analyzed for calcium fluoride (CaF2) content using XRF and XRD testing. Samples include pure CaF2, pure oyster shell, and oyster shells treated with acid. Based from the XRF results, natural oyster shell (w/ and w/o HNO3) had high percentage of calcium about 49.64% and 47.45%, next to the pure calcium fluoride of 51.08%. X-ray diffractrogram shows that oyster sample had the nearest desired structure of CaF2 compared with two seashells relative to the pure CaF2 as standard materials. Results show that all of the natural oyster samples displayed TL emission glow curves at the temperature range 200-300oC. It was also found that pure oyster sample has better TL response as compared to the treated ones. The researchers concluded that the calcium fluoride from oyster shells (without acid and heated) is a potentially good low-cost TLD raw material and may be used as an alternative for the much more expensive LiF dosimeters. (Authors)

  15. Solubility of a new calcium silicate-based root-end filling material

    OpenAIRE

    Shishir Singh; Rajesh Podar; Shifali Dadu; Gaurav Kulkarni; Rucheet Purba

    2015-01-01

    Introduction: The purpose of this study was to compare solubility of a new calcium silicate-based cement, Biodentine with three commonly used root-end filling materials viz. glass-ionomer cement (GIC), intermediate restorative material (IRM), and mineral trioxide aggregate (MTA). Materials and Methods: Twenty stainless steel ring molds were filled with cements corresponding to four groups (n = 5). The weight of 20 dried glass bottles was recorded. Samples were transferred to bottles conta...

  16. New bone implant material with calcium sulfate and Ti modified hydroxyapatite

    OpenAIRE

    A. Ślósarczyk; J. Czechowska; Z. Paszkiewicz; A. Zima

    2010-01-01

    (TiHA) to develop a novel bone cement. Results of previous studies showed that bioactive potential of titanium modified hydroxyapatite ceramics is higher than that of pure HA. Calcium sulfate hemihydrate is also considered as a safe, biocompatible material, however it has been criticized for its rapid resorption. Combination of these materials may result in new cement type material with surgical handiness and selective resorption.Design/methodology/approach: TiHA was obtained by a wet method....

  17. Preparation and characterization of multifunctional magnetic mesoporous calcium silicate materials

    International Nuclear Information System (INIS)

    We have prepared multifunctional magnetic mesoporous Fe–CaSiO3 materials using triblock copolymer (P123) as a structure-directing agent. The effects of Fe substitution on the mesoporous structure, in vitro bioactivity, magnetic heating ability and drug delivery property of mesoporous CaSiO3 materials were investigated. Mesoporous Fe–CaSiO3 materials had similar mesoporous channels (5–6 nm) with different Fe substitution. When 5 and 10% Fe were substituted for Ca in mesoporous CaSiO3 materials, mesoporous Fe–CaSiO3 materials still showed good apatite-formation ability and had no cytotoxic effect on osteoblast-like MC3T3-E1 cells evaluated by the elution cell culture assay. On the other hand, mesoporous Fe–CaSiO3 materials could generate heat to raise the temperature of the surrounding environment in an alternating magnetic field due to their superparamagnetic property. When we use gentamicin (GS) as a model drug, mesoporous Fe–CaSiO3 materials release GS in a sustained manner. Therefore, magnetic mesoporous Fe–CaSiO3 materials would be a promising multifunctional platform with bone regeneration, local drug delivery and magnetic hyperthermia. (paper)

  18. Biodiesel production using calcium manganese oxide as catalyst and different raw materials

    International Nuclear Information System (INIS)

    Highlights: ► Biodiesel production using a calcium manganese oxide catalyst was studied. ► The active specie was Ca0.9Mn0.1O and its deactivation occurred by hydration. ► The studied catalyst presented lower activation temperature than CaO. ► Biodiesel production and quality using different raw materials is reported. ► Compared to the conventional process, biodiesel water content improved. - Abstract: The use of heterogeneous catalysts for biodiesel production aims to simplify the production process as well as to reduce purification costs and related environmental impacts. Calcium manganese oxide was recently identified by the authors as an interesting heterogeneous catalyst for biodiesel production from animal fat; however, the difference between this and other catalysts, the catalyst activation/deactivation mechanisms, its behaviour in the synthesis using different raw materials as well as the impacts of its use on product quality remained unclear. Therefore, the present work: (i) compared biodiesel production using calcium manganese oxide and other catalysts (CaO and NaOH); (ii) studied the reasons leading to activation/deactivation of the heterogeneous catalyst; (iii) analysed biodiesel heterogeneous synthesis using calcium manganese oxide and different raw materials (lard, waste frying oil and a mixture); and (iv) evaluated raw material and catalyst impact on the product quality. Considering the use of different catalysts, the results showed that, after 8 h of reaction, product purity was similar using the different catalysts, being 92.5 wt.% using both NaOH and calcium manganese oxide and 93.8 wt.% using CaO. The active species of the heterogeneous catalysts were CaO, in the case of calcinated calcium carbonate, and Ca0.9Mn0.1O, in the case of calcinated calcium manganese oxide. Because the deactivating species were different for both catalysts, the calcium manganese oxide required lower activation temperature, which should be an advantage. When

  19. Thermal neutron absorbing composite organic fiber material

    International Nuclear Information System (INIS)

    Purpose: To obtain clothing materials easy to put on by plasma spray of inorganic material containing elements with a large thermal neutron absorption cross section on a fiberous structure mainly composed of organic fibers. Constitution: The composite organic fiber material comprises flame-spray molding products containing elements with a large thermal neutron absorbing cross section and fiberous structure mainly composed of organic fibers having a melting point lower than that for the flame-spray molding products and they are integrated as a multilayered structure. The flame-spray fabrication is applied by melting and pulverizing starting materials in plasmas and then forming in the shape of a film, sponge or flake on a sheet-like product while carrying them on a plasma stream etc. The binder layer can be saved or reduced significantly by constituting the neutron absorbing material with the flame-spray molding products. (Takahashi, M.)

  20. Calcium-fortified beverage supplementation on body composition in postmenopausal women

    Directory of Open Access Journals (Sweden)

    Remig Valentina M

    2005-06-01

    Full Text Available Abstract Background We investigated the effects of a calcium-fortified beverage supplemented over 12 months on body composition in postmenopausal women (n = 37, age = 48–75 y. Methods Body composition (total-body percent fat, %FatTB; abdominal percent fat, %FatAB was measured with dual energy x-ray absorptiometry. After baseline assessments, subjects were randomly assigned to a free-living control group (CTL or the supplement group (1,125 mg Ca++/d, CAL. Dietary intake was assessed with 3-day diet records taken at baseline and 12 months (POST. Physical activity was measured using the Yale Physical Activity Survey. Results At 12 months, the dietary calcium to protein ratio in the CAL group (32.3 ± 15.6 mg/g was greater than the CTL group (15.2 ± 7.5 mg/g. There were no differences from baseline to POST between groups for changes in body weight (CAL = 0.1 ± 3.0 kg; CTL = 0.0 ± 2.9 kg, %FatTB (CAL = 0.0 ± 2.4%; CTL = 0.5 ± 5.4%, %FatAB (CAL = -0.4 ± 8.7%; CTL = 0.6 ± 8.7%, or fat mass (CAL = 1.3 ± 2.6 kg; CTL = 1.3 ± 2.7 kg. Conclusion These results indicate that increasing the calcium to protein ratio over two-fold by consuming a calcium-fortified beverage for 12 months did not decrease body weight, body fat, or abdominal fat composition in postmenopausal women.

  1. Novel calcium hexaluminate/spinel-alumina composites with graded microstructures and mechanical properties

    Science.gov (United States)

    Yi, Shuai; Huang, Zhaohui; Huang, Juntong; Fang, Minghao; Liu, Yan'gai; Zhang, Shaowei

    2014-03-01

    Calcium hexaluminate (CA6) was incorporated into the matrix of magnesio aluminate spinel-alumina (MA-A) via infiltration of a porous preform fabricated from α-Al2O3 and MgO powders with a saturated calcium acetate solution and subsequent firing, forming CA6/(MA-A) functionally composites with graded fracture toughness. Actually, the porous preform was partially and perpendicularly immersed (1/4 of its length) in the solution. Owing to the capillary action, the calcium acetate solution was absorbed into the porous preform, and the different absorption distance led to the graded solution concentration in the height direction of the porous preform. The in-situ formation of CA6 conferred graded microstructures, as well as improved mechanical properties on the resultant composites. The CA6 content decreased gradually along the solution absorption direction, i.e., from one end [CA6/(MA-A) region] immersed in solution to the other end [MA-A region], reducing evidently the formation of layered structure along the direction, while increasing gradually the formation of spherical alumina particles. The CA6/(MA-A) region had a better toughness that could prevent the crack propagation and improve the spalling resistance. Meanwhile, the MA-A region could provide structural support, because of the higher Vickers hardness and density.

  2. Moisture transport and adsorption on silica gel-calcium chloride composite adsorbents

    International Nuclear Information System (INIS)

    A measurement of moisture uptake curves in silica gel-calcium composite adsorbents is performed by using the thermal gravimetrical method in a relative vapor pressure range from 0.5 to 0.9 at different temperature levels of 25, 35 and 45 deg. C, respectively. Also, dynamic adsorption curves individually corresponding to the temperature and relative pressure conditions of (25 deg. C, 0.7) (35 deg. C, 0.7) and (35 deg. C, 0.5) have been measured. This experimental study shows that the sorption rate is highest for non-impregnated macroporous silica gel; however, the same silica gel impregnated with calcium chloride has a much greater final water loading. This confirms that composite adsorbents result in a better adsorption performance compared with non-impregnated silica gel, leading to a trade off in finalizing the content of CaCl2 in the composite. Through theoretical analysis on the experimental data, it is found that the saturated adsorption data can be well fitted by the FHH model and the dynamic adsorption data well fitted by the Crank diffusion model, simultaneously yielding the effective solid side mass diffusivities. A comparison with these obtained diffusion coefficients further supports that the mass diffusivity in the composite adsorbent also increases with an increase in temperature, as well as in humidity, but drastically decreases due to the presence of salt inside the matrix pores compared with the non-impregnated host matrix

  3. Research on the preparation, biocompatibility and bioactivity of magnesium matrix hydroxyapatite composite material.

    Science.gov (United States)

    Linsheng, Li; Guoxiang, Lin; Lihui, Li

    2016-08-12

    In this paper, magnesium matrix hydroxyapatite composite material was prepared by electrophoretic deposition method. The optimal process parameters of electrophoretic deposition were HA suspension concentration of 0.02 kg/L, aging time of 10 days and voltage of 60 V. Animal experiment and SBF immersion experiment were used to test the biocompatibility and bioactivity of this material respectively. The SD rats were divided into control group and implant group. The implant surrounding tissue was taken to do tissue biopsy, HE dyed and organizational analysis after a certain amount of time in the SD rat body. The biological composite material was soaked in SBF solution under homeothermic condition. After 40 days, the bioactivity of the biological composite material was evaluated by testing the growth ability of apatite on composite material. The experiment results showed that magnesium matrix hydroxyapatite biological composite material was successfully prepared by electrophoretic deposition method. Tissue hyperplasia, connective tissue and new blood vessels appeared in the implant surrounding soft tissue. No infiltration of inflammatory cells of lymphocytes and megakaryocytes around the implant was found. After soaked in SBF solution, a layer bone-like apatite was found on the surface of magnesium matrix hydroxyapatite biological composite material. The magnesium matrix hydroxyapatite biological composite material could promot calcium deposition and induce bone-like apatite formation with no cytotoxicity and good biocompatibility and bioactivity. PMID:27567779

  4. Stratospheric experiments on curing of composite materials

    Science.gov (United States)

    Chudinov, Viacheslav; Kondyurin, Alexey; Svistkov, Alexander L.; Efremov, Denis; Demin, Anton; Terpugov, Viktor; Rusakov, Sergey

    2016-07-01

    Future space exploration requires a large light-weight structure for habitats, greenhouses, space bases, space factories and other constructions. A new approach enabling large-size constructions in space relies on the use of the technology of polymerization of fiber-filled composites with a curable polymer matrix applied in the free space environment on Erath orbit. In orbit, the material is exposed to high vacuum, dramatic temperature changes, plasma of free space due to cosmic rays, sun irradiation and atomic oxygen (in low Earth orbit), micrometeorite fluence, electric charging and microgravitation. The development of appropriate polymer matrix composites requires an understanding of the chemical processes of polymer matrix curing under the specific free space conditions to be encountered. The goal of the stratospheric flight experiment is an investigation of the effect of the stratospheric conditions on the uncured polymer matrix of the composite material. The unique combination of low residual pressure, high intensity UV radiation including short-wave UV component, cosmic rays and other aspects associated with solar irradiation strongly influences the chemical processes in polymeric materials. We have done the stratospheric flight experiments with uncured composites (prepreg). A balloon with payload equipped with heater, temperature/pressure/irradiation sensors, microprocessor, carrying the samples of uncured prepreg has been launched to stratosphere of 25-30 km altitude. After the flight, the samples have been tested with FTIR, gel-fraction, tensile test and DMA. The effect of cosmic radiation has been observed. The composite was successfully cured during the stratospheric flight. The study was supported by RFBR grants 12-08-00970 and 14-08-96011.

  5. Using Composite Materials in a Cryogenic Pump

    Science.gov (United States)

    Batton, William D.; Dillard, James E.; Rottmund, Matthew E.; Tupper, Michael L.; Mallick, Kaushik; Francis, William H.

    2008-01-01

    Several modifications have been made to the design and operation of an extended-shaft cryogenic pump to increase the efficiency of pumping. In general, the efficiency of pumping a cryogenic fluid is limited by thermal losses which is itself caused by pump inefficiency and leakage of heat through the pump structure. A typical cryogenic pump includes a drive shaft and two main concentric static components (an outer pressure containment tube and an intermediate static support tube) made from stainless steel. The modifications made include replacement of the stainless-steel drive shaft and the concentric static stainless-steel components with components made of a glass/epoxy composite. The leakage of heat is thus reduced because the thermal conductivity of the composite is an order of magnitude below that of stainless steel. Taking advantage of the margin afforded by the decrease in thermal conductivity, the drive shaft could be shortened to increase its effective stiffness, thereby increasing the rotordynamic critical speeds, thereby further making it possible to operate the pump at a higher speed to increase pumping efficiency. During the modification effort, an analysis revealed that substitution of the shorter glass/epoxy shaft for the longer stainless-steel shaft was not, by itself, sufficient to satisfy the rotordynamic requirements at the desired increased speed. Hence, it became necessary to increase the stiffness of the composite shaft. This stiffening was accomplished by means of a carbon-fiber-composite overwrap along most of the length of the shaft. Concomitantly with the modifications described thus far, it was necessary to provide for joining the composite-material components with metallic components required by different aspects of the pump design. An adhesive material formulated specially to bond the composite and metal components was chosen as a means to satisfy these requirements.

  6. Investigation of laundering and dispersion approaches for silica and calcium phosphosilicate composite nanoparticles synthesized in reverse micelles

    Science.gov (United States)

    Tabakovic, Amra

    Nanotechnology, the science and engineering of materials at the nanoscale, is a booming research area with numerous applications in electronic, cosmetic, automotive and sporting goods industries, as well as in biomedicine. Composite nanoparticles (NPs) are of special interest since the use of two or more materials in NP design imparts multifunctionality on the final NP constructs. This is especially relevant for applications in areas of human healthcare, where the use of dye or drug doped composite NPs is expected to improve the diagnosis and treatment of cancer and other serious illnesses. Since the physicochemical properties of NP suspensions dictate the success of these systems in biomedical applications, especially drug delivery of chemotherapeutics, synthetic routes which offer precise control of NP properties, especially particle diameter and colloidal stability, are utilized to form a variety of composite NPs. Formation of NPs in reverse, or water-in-oil, micelles is one such synthetic approach. However, while the use of reverse micelles to form composite NPs offers precise control over NP size and shape, the post-synthesis laundering and dispersion of synthesized NP suspensions can still be a challenge. Reverse micelle synthetic approaches require the use of surfactants and low dielectric constant solvents, like hexane and cyclohexane, as the oil phase, which can compromise the biocompatibility and colloidal stability of the final composite NP suspensions. Therefore, appropriate dispersants and solvents must be used during laundering and dispersion to remove surfactant and ensure stability of synthesized NPs. In the work presented in this dissertation, two laundering and dispersion approaches, including packed column high performance liquid chromatography (HPLC) and centrifugation (sedimentation and redispersion), are investigated for silver core silica (Ag-SiO2) and calcium phosphosilicate (Caw(HxPO4)y(Si(OH)zOa) b · cH2O, CPS) composite NP suspensions

  7. FEM modelling of magnetostrictive composite materials

    OpenAIRE

    L.A. Dobrzański; A. Tomiczek; G. Dziatkiewicz

    2012-01-01

    Purpose: The paper presents a numerical model for the analysis of magnetostriction in composite materials in polymer matrix reinforced by Tb0.3Dy0.7Fe1.9 particles. The properties were determined by taking into account the applied stresses and magnetic field intensity.Design/methodology/approach: The finite element method for simulation the magnetostriction phenomenon was established by theoretical analysis based on experimental results.Findings: Thanks to the finite element method the numeri...

  8. On the effective conductivity of composite materials

    OpenAIRE

    Kornyushin, Yuri

    2009-01-01

    A composite conductive material, which consists of fibers of a high conductivity in a matrix of low conductivity, is discussed. The effective conductivity of the system considered is calculated in Clausius-Mossotti approximation. Obtained relationships can be used to calculate the conductivity of a matrix, using experimentally measured parameters. Electric fields in the matrix and the inclusions are calculated. It is shown that the field in a low-conductivity matrix can be much higher than th...

  9. Composite materials in flexible multibody systems

    OpenAIRE

    Neto, Maria Augusta; Ambrósio, Jorge A. C.; Leal, Rogério P.

    2006-01-01

    In this work the flexible multibody dynamics formulations of complex models are extended to include elastic components made of laminated composite materials. The only limitation for the deformation of a structural member is that it must be elastic and linear when described in a body fixed frame. A finite element model for each flexible body is obtained such that the nodal coordinates are described with respect to the body fixed frame and the inertia terms involved in the mass matrix and gyros...

  10. Modelling electrical properties of composite materials

    OpenAIRE

    Mårtensson, Eva

    2003-01-01

    Composite field grading materials are used to avoid stressconcentrations in high voltage applications such as cableaccessories and generator or motor end windings. The compositematerials consist of an insulating matrix filled with suitableconducting or semi-conducting particles. Silicon carbide (SiC)powder is one such filler that is being employed. The compositematerials display complex electrical characteristics that aredependent on filler properties, particle concentration,frequency and ele...

  11. Epoxide composite materials with carbon nanotubes

    International Nuclear Information System (INIS)

    Methods of formation and physical properties of epoxide composite materials reinforced with carbon nanotubes are considered. An analogy is made between the relaxation properties of carbon nanotubes and macromolecules. The concentration dependences of the electrical conductivity of the epoxy polymers filled with single-walled and multi-walled carbon nanotubes are discussed. Modern views on the mechanism of reinforcement of polymers with nanotubes are outlined. The bibliography includes 143 references.

  12. ACEE Composite Structures Technology: Review of selected NASA research on composite materials and structures

    Science.gov (United States)

    1984-01-01

    The NASA Aircraft Energy Efficiency (ACEE) Composite Primary Aircraft Structures Program was designed to develop technology for advanced composites in commercial aircraft. Research on composite materials, aircraft structures, and aircraft design is presented herein. The following parameters of composite materials were addressed: residual strength, damage tolerance, toughness, tensile strength, impact resistance, buckling, and noise transmission within composite materials structures.

  13. Nanocellulose Composite Materials Synthesizes with Ultrasonic Agitation

    Science.gov (United States)

    Kidd, Timothy; Folken, Andrew; Fritch, Byron; Bradley, Derek

    We have extended current techniques in forming nanocellulose composite solids, suspensions and aerogels to enhance the breakdown of cellulose into its molecular components. Using only mechanical processing which includes ball milling, using a simple mortar and pestle, and ultrasonic agitation, we are able to create very low concentration uniform nanocellulose suspensions in water, as well as incorporate other materials such as graphite, carbon nanotubes, and magnetic materials. Of interest is that no chemical processing is necessary, nor is the use of nanoparticles, necessary for composite formation. Using both graphite and carbon nanotubes, we are able to achieve conducting nanocellulose solids and aerogels. Standard magnetic powder can also be incorporated to create magnetic solids. The technique also allows for the creation of an extremely fine nanocellulose suspension in water. Using extremely low concentrations, less than 1% cellulose by mass, along with careful control over processing parameters, we are able to achieve highly dilute, yet homogenous nanocellulose suspensions. When air dried, these suspensions have similar hardness and strength properties to those created with more typical starting cellulose concentrations (2-10%). However, when freeze-dried, these dilute suspensions form aerogels with a new morphology with much higher surface area than those with higher starting concentrations. We are currently examining the effect of this higher surface area on the properties of nanocellulose aerogel composites and how it influences the impact of incorporating nanocellulose into other polymer materials.

  14. Environment Friendly Composite Materials: Biocomposites and Green Composites

    Directory of Open Access Journals (Sweden)

    B. C. Mitra

    2014-05-01

    Full Text Available Biocomposites can supplement and eventually replace petroleum-based composite materials in several applications. Several critical issues related to bio-fiber surface treatments is to make it a more suitable matrix for composite application and promising techniques need to be solved to design biocomposite of interest. The main motivation for developing biocomposites has been and still is to create a new generation of fiber reinforced plastics material competitive with glass fiber reinforced ones which are environmentally compatible in terms of products, use and renewal. There is an immense opportunity in developing new biobased products, but the real challenge isto design suitable bio-based products through innovation ideas. Green materials are the wave of the future. Bionanocomposites have very strong future prospects, though the present low level of production, some deficiency intechnology and high cost restrict them from a wide range of applications.Defence Science Journal, Vol. 64, No. 3, May 2014, pp. 244-261, DOI:http://dx.doi.org/10.14429/dsj.64.7323

  15. Elution of Monomers from Provisional Composite Materials

    Directory of Open Access Journals (Sweden)

    Simon Daniel Schulz

    2015-01-01

    Full Text Available The aim of this study was to evaluate the elution of substances from different materials used for the manufacturing of temporary indirect restorations, after storage in saliva and ethanol 75%. 10 samples of three chemically cured materials (Protemp 3 Garant, Systemp.c&b, and Trim and one light-cured material (Clip F were stored in saliva and ethanol 75% for 24 h, 7, and days 28 days. From the storage media at each time period, samples were prepared and analysed by LC-MS/MS, in order to access the elution of monomers. The results differed among the materials (P ≤ 0.05. No monomers were detected in the samples of Protemp 3 Garant and Clip F. Substances were detected only in ethanol samples of Systemp.c&b and Trim. The amount of BisGMA, TEGDMA, and UDMA 2 released from Systemp.c&b was higher compared to Trim. Storage time affected the release of substances (P ≤ 0.05. The highest release was observed within the first 24 h. It can be concluded that provisional resin composite materials do not show high release of monomers and this release is material dependent. However, the detection of additional peaks during the analysis, suggesting the formation of by-products of the eluted substances, may not be in favour of these materials with respect to their toxicity.

  16. Synthesizing Smart Polymeric and Composite Materials

    Science.gov (United States)

    Gong, Chaokun

    Smart materials have been widely investigated to explore new functionalities unavailable to traditional materials or to mimic the multifunctionality of biological systems. Synthetic polymers are particularly attractive as they already possess some of the attributes required for smart materials, and there are vast room to further enhance the existing properties or impart new properties by polymer synthesis or composite formulation. In this work, three types of smart polymer and composites have been investigated with important new applications: (1) healable polymer composites for structural application and healable composite conductor for electronic device application; (2) conducting polymer polypyrrole actuator for implantable medical device application; and (3) ferroelectric polymer and ceramic nanoparticles composites for electrocaloric effect based solid state refrigeration application. These application entail highly challenging materials innovation, and my work has led to significant progress in all three areas. For the healable polymer composites, well known intrinsically healable polymer 2MEP4F (a Diels-Alder crosslinked polymer formed from a monomer with four furan groups and another monomer with two maleimide groups) was first chosen as the matrix reinforced with fiber. Glass fibers were successfully functionalized with maleimide functional groups on their surface. Composites from functionalized glass fibers and 2MEP4F healable polymer were made to compare with composites made from commercial carbon fibers and 2MEP4F polymer. Dramatically improved short beam shear strength was obtained from composite of functionalized glass fibers and 2MEP4F polymer. The high cost of 2MEP4F polymer can potentially limit the large-scale application of the developed healable composite, we further developed a new healable polymer with much lower cost. This new polymer was formed through the Diels-Alder crosslinking of poly(furfuryl alcohol) (PFA) and 1,1'-(Methylenedi-4

  17. Biomimetic coating of calcium phosphate on biometallic materials

    Institute of Scientific and Technical Information of China (English)

    ZHANG Er-lin; YANG Ke

    2005-01-01

    The biomimetic coating process in comparison with other processes is reviewed. This processing shows advantages in the surface bio-modification, such as low cost and flexible processing, wide range of apatite composition and thickness, non-line-of-sight characteristic and possibility to coat polymers and porous implants. The bio-mimetic apatite coating is made up of larger number of globules with size of 1-5μm. Each globule is a group of numerous flakes with a size range of 100-200nm to 30μm in length and 0.1-1μm in thickness. In-vitro and in-vivo studies show that the biomimetic apatite coating can promote an early and strong bonding to bone or promote the bone in-growth into the porous structure, which will be beneficial to the cementless stable fixation of orthopaedic implants. Recently developed co-precipitation of a kind of protein molecules into the HA coating shows much promising.

  18. Fabrication of cefuroxime-impregnated calcium sulfate: Polycaprolactone composite implant for osteomyelitis

    Directory of Open Access Journals (Sweden)

    Gupta Himanshu

    2009-01-01

    Full Text Available Osteomyelitis is characterized as an inflammatory bone disease caused by pyrogenic bacteria. As oral bioavailabilities of antibiotics are low, a regimen of 6 weeks of intravenous antibiotic is necessary for adequate therapy. Although the dose of antibiotic administered systemically is high, therapeutically effective drug concentrations are not always achieved at the site of infection. This problem can be overcome by the use of local antibiotics from a biodegradable implant for chronic osteomyelitis that can deliver the drug at least for 6 weeks. The implant delivers high antibiotic concentration at tissue levels, obliterates dead space, aids bone repair and does not need to be removed. The aim of this study was to develop and evaluate a calcium sulfate and polycaprolactone (PCL-based composite biodegradable implantable delivery system of cefuroxime for the localized treatment of osteomyelitis that can deliver the drug for at least 6 weeks. The PCL and calcium sulfate composite system has not been studied yet. Interaction studies were carried out to check any incompatibility between the ingredients. Implants were prepared by a modified fabrication technique to avoid solvent use. The prepared implants were evaluated for various in vitro parameters like dimensions, hardness, tensile strength, drug release profile, sterility test and morphological changes in pellet before and after drug release. The pellets were also tested for microbiological efficacy and compared with a plain drug solution in different concentrations. Developed pellets are regular in shape and size with good tensile strength. The release profile displayed drug levels above the minimum inhibitory concentration continuously for up to 2 months. A wide zone of inhibition by the pellet against Staphylococcus aureus as compared with the drug solution proves its efficacy in the treatment of osteomyelitis. Results show that the developed calcium sulfate and PCL-based composite

  19. Hydrothermal Synthesis of Xonotlite-type Calcium Silicate Insulation Material Using Industrial Zirconium Waste Residue

    Institute of Scientific and Technical Information of China (English)

    JIANG Jinguo; CUI Chong; LIU Jinqiang; LIAO Wenli

    2011-01-01

    Xonotlite-type insulation material was prepared by hydrothermal synthesis technology using industrial zirconium waste residue in this paper, and the phase analysis together with the observation of micro-morphology were also carried out by XRD, SEM and TEM. The density and thermal conductivity were measured finally. The results indicate, chlorine ion impurity contained in zirconium waste residue can be removed effectively via water washed process, and the reactive activity of silicon dioxide is almost not affected,which make it be a good substitution of silicon material for the preparation of calcium silicate insulation material by hydrothermal synthesis technique. The density and thermal conductivity of xonotlite-type calcium silicate insulation material obtained by hydrothermal synthesis technique can reach 159 kg/m3, 0.049 W/(m·°C), respectively, meeting with National Standard well, when synthesis conditions are selected as follows: Ca/Si molar ratio equal to 1, synthesis temperature at 210 ℃ and kept for 8 hrs. It provides a new approach to realize lightweight and low thermal conductivity of calcium silicate insulation material.

  20. Properties of nanoclay PVA composites materials

    Directory of Open Access Journals (Sweden)

    Mohamed H. M. Ali

    2012-03-01

    Full Text Available Polyvinyl alcohol (PVA/ Na-rich Montmorillonite (MMT nanocomposites were prepared using solution method to create polymer-clay nanocomposite (PCN material. The PCN material was studied using X-ray diffraction (XRD, demonstrating polymer-clay intercalation that has a high d-spacing (lower diffraction angles in the PCN XRD pattern, compared to the pure MMT clay XRD pattern, which has a low d-spacing (high diffraction angles. The nano-scanning electron microscope (NSEM was used to study the morphological image of the PVA, MMT and PCN materials. The results showed that intercalation that took place between the PVA and MMT produced the PCN material. The mechanical properties of the pure PVA and the intercalated polymer material were studied. It was found that the small amount of MMT clay made the tensile modulus and percentage of the total elongation of the nano-composite significantly higher than the pure PVA polymer value, due to polymer-clay intercalation. The thermal stability of the intercalated polymer has been studied using thermal analytical techniques such as thermogravimetric analysis (TGA and differential scanning calorimetry (DSC. The results showed that the PCN material is more thermally stable than the pure PVA polymer.

  1. Chemical composition and dry matter digestibility of sugar cane oxide treated with calcium

    OpenAIRE

    C.O. Romão; G.G.P. Carvalho; V.M. Leite; Santos, A. S.; D.M.T. Chagas; O.L. Ribeiro; P.A. Oliveira; Magalhães, A F; A.J.V. Pires

    2014-01-01

    The aim of this study was to identify the most adequate level of calcium oxide (CaO) in the treatment of sugar cane by evaluating the chemical composition and in vitro digestibility of dry matter. The sugar cane was homogenized with CaO levels 0, 0.75, 1.5, 2.25, 3.0, 3.75 and 4.5%, in natura matter, for 24 hours. The dry matter and mineral matter increased, while the organic matter of the sugar cane decreased (P

  2. Current perspectives of bio-ceramic technology in endodontics: calcium enriched mixture cement - review of its composition, properties and applications

    Science.gov (United States)

    Nawal, Ruchika Roongta; Talwar, Sangeeta; Verma, Mahesh

    2015-01-01

    Advancements in bio-ceramic technology has revolutionised endodontic material science by enhancing the treatment outcome for patients. This class of dental materials conciliates excellent biocompatibility with high osseoconductivity that render them ideal for endodontic care. Few recently introduced bio-ceramic materials have shown considerable clinical success over their early generations in terms of good handling characteristics. Calcium enriched mixture (CEM) cement, Endosequence sealer, and root repair materials, Biodentine and BioAggregate are the new classes of bio-ceramic materials. The aim of this literature review is to present investigations regarding properties and applications of CEM cement in endodontics. A review of the existing literature was performed by using electronic and hand searching methods for CEM cement from January 2006 to December 2013. CEM cement has a different chemical composition from that of mineral trioxide aggregate (MTA) but has similar clinical applications. It combines the biocompatibility of MTA with more efficient characteristics, such as significantly shorter setting time, good handling characteristics, no staining of tooth and effective seal against bacterial leakage. PMID:25671207

  3. Current perspectives of bio-ceramic technology in endodontics: calcium enriched mixture cement - review of its composition, properties and applications.

    Science.gov (United States)

    Utneja, Shivani; Nawal, Ruchika Roongta; Talwar, Sangeeta; Verma, Mahesh

    2015-02-01

    Advancements in bio-ceramic technology has revolutionised endodontic material science by enhancing the treatment outcome for patients. This class of dental materials conciliates excellent biocompatibility with high osseoconductivity that render them ideal for endodontic care. Few recently introduced bio-ceramic materials have shown considerable clinical success over their early generations in terms of good handling characteristics. Calcium enriched mixture (CEM) cement, Endosequence sealer, and root repair materials, Biodentine and BioAggregate are the new classes of bio-ceramic materials. The aim of this literature review is to present investigations regarding properties and applications of CEM cement in endodontics. A review of the existing literature was performed by using electronic and hand searching methods for CEM cement from January 2006 to December 2013. CEM cement has a different chemical composition from that of mineral trioxide aggregate (MTA) but has similar clinical applications. It combines the biocompatibility of MTA with more efficient characteristics, such as significantly shorter setting time, good handling characteristics, no staining of tooth and effective seal against bacterial leakage. PMID:25671207

  4. Compósitos colágeno aniônico: fosfato de cálcio. Preparação e caracterização Collagen: calcium phosphate composites. Preparation and characterization

    Directory of Open Access Journals (Sweden)

    Marcos Roberto Bet

    1997-10-01

    Full Text Available Anionic collagen: calcium phosphate composite was obtained by controlled mixing of collagen and calcium phosphate until the consistence of a past. Material was characterized by a Ca/P ratio of 1.55, with a X-ray diffraction pattern similar to that for hydroxyapatite. Differential Scanning Calorimetry showed that the protein is not denatured under the processing conditions. Scanning Electronic Microscopy showed that the mineral phase are regularly covered with collagen fibers, indicating that anionic collagen is efficient in the preparation of stable form of calcium phosphate ceramic paste.

  5. A biocompatible hybrid material with simultaneous calcium and strontium release capability for bone tissue repair.

    Science.gov (United States)

    Almeida, J Carlos; Wacha, András; Gomes, Pedro S; Alves, Luís C; Fernandes, M Helena Vaz; Salvado, Isabel M Miranda; Fernandes, M Helena R

    2016-05-01

    The increasing interest in the effect of strontium in bone tissue repair has promoted the development of bioactive materials with strontium release capability. According to literature, hybrid materials based on the system PDMS-SiO2 have been considered a plausible alternative as they present a mechanical behavior similar to the one of the human bone. The main purpose of this study was to obtain a biocompatible hybrid material with simultaneous calcium and strontium release capability. A hybrid material, in the system PDMS-SiO2-CaO-SrO, was prepared with the incorporation of 0.05mol of titanium per mol of SiO2. Calcium and strontium were added using the respective acetates as sources, following a sol-gel technique previously developed by the present authors. The obtained samples were characterized by FT-IR, solid-state NMR, and SAXS, and surface roughness was analyzed by 3D optical profilometry. In vitro studies were performed by immersion of the samples in Kokubo's SBF for different periods of time, in order to determine the bioactive potential of these hybrids. Surfaces of the immersed samples were observed by SEM, EDS and PIXE, showing the formation of calcium phosphate precipitates. Supernatants were analyzed by ICP, revealing the capability of the material to simultaneously fix phosphorus ions and to release calcium and strontium, in a concentration range within the values reported as suitable for the induction of the bone tissue repair. The material demonstrated to be cytocompatible when tested with MG63 osteoblastic cells, exhibiting an inductive effect on cell proliferation and alkaline phosphatase activity. PMID:26952443

  6. Bioactivity and corrosion properties of gelatin-containing and strontium-doped calcium phosphate composite coating

    Science.gov (United States)

    Huang, Yong; Yan, Yajing; Pang, Xiaofeng; Ding, Qiongqiong; Han, Shuguang

    2013-10-01

    To improve coating corrosion resistance and bioactivity, strontium (Sr) and gelatin (GLT) were simultaneously incorporated in calcium phosphate (Ca-P) to form Sr-Ca-P/GLT composite coating on titanium (Ti) by electrodeposition. The surface morphology, chemical composition, phase identification, bond strength, corrosion resistance, and cytocompatibility of the films were studied. Results revealed that the Sr-Ca-P/GLT layer was rough and inhomogeneous, with floral-like crystals or flake agglomerate morphology. The Sr-Ca-P crystals were Sr-doped apatite (hydroxyapatite and brushite), and Sr2+ ions and GLT were homogeneously distributed in the Ca-P coating. The thickness of the composite coating was almost 10 μm without delamination and/or cracking at the interface. The bond strength of the composite coating was 5.6 ± 1.8 MPa. The Sr-Ca-P/GLT coated Ti had lower corrosion rates than bare Ti, suggesting a protective character of the composite coating. Osteoblast cellular tests demonstrated that the Sr-Ca-P/GLT composite coating better enhanced the in vitro biocompatibility of Ti than Ca-P coating.

  7. Bioactivity and corrosion properties of gelatin-containing and strontium-doped calcium phosphate composite coating

    International Nuclear Information System (INIS)

    To improve coating corrosion resistance and bioactivity, strontium (Sr) and gelatin (GLT) were simultaneously incorporated in calcium phosphate (Ca–P) to form Sr–Ca–P/GLT composite coating on titanium (Ti) by electrodeposition. The surface morphology, chemical composition, phase identification, bond strength, corrosion resistance, and cytocompatibility of the films were studied. Results revealed that the Sr–Ca–P/GLT layer was rough and inhomogeneous, with floral-like crystals or flake agglomerate morphology. The Sr–Ca–P crystals were Sr-doped apatite (hydroxyapatite and brushite), and Sr2+ ions and GLT were homogeneously distributed in the Ca–P coating. The thickness of the composite coating was almost 10 μm without delamination and/or cracking at the interface. The bond strength of the composite coating was 5.6 ± 1.8 MPa. The Sr–Ca–P/GLT coated Ti had lower corrosion rates than bare Ti, suggesting a protective character of the composite coating. Osteoblast cellular tests demonstrated that the Sr–Ca–P/GLT composite coating better enhanced the in vitro biocompatibility of Ti than Ca–P coating.

  8. Calcium Intake and Body Composition in African-American Children and Adolescents at Risk for Overweight and Obesity

    Directory of Open Access Journals (Sweden)

    Frances A. Tylavsky

    2010-09-01

    Full Text Available This study examined the role of calcium intake on body composition in 186 African-American adolescents at risk for overweight and obesity. The average weight of 89.8 kg ± 23.6 (SD had a mean BMI z score of 2.2. Females with a calcium intake of < 314 mg/day had higher percent fat mass compared to those with the highest calcium intakes that were ≥ 634 mg/day. Compared to those with a low calcium intake (< 365 mg/day, those with the highest calcium intake of > 701 mg/day had higher intake of thiamin, folate, cobalamin, vitamin D, phosphorus, iron, zinc.

  9. Study on the bonding strength between calcium phosphate/chitosan composite coatings and a Mg alloy substrate

    International Nuclear Information System (INIS)

    Highlights: ► Calcium phosphate/chitosan composite coatings on the MAO-AZ91D alloy were prepared. ► The bonding force between the coating and the magnesium alloy was optimized. ► The composite coating slowed down the corrosion rate of magnesium alloy in m-SBF. - Abstract: In order to improve the bonding strength between calcium phosphate/chitosan composite coatings and a micro-arc oxidized (MAO)-AZ91D Mg alloy, different influencing parameters were investigated in the process of electrophoretic deposition (EPD) followed by conversion in a phosphate buffer solution (PBS). Surface morphology and phase constituents of the as-prepared materials were investigated by using X-ray diffractometer (XRD), Fourier-transformed infrared spectrophotometer (FTIR), Raman spectrometer, scanning electron microscope (SEM) with an energy dispersive spectrometer (EDS), and a thermo gravimetric and differential thermal analyzer (TG–DTA). Scratch tests were carried out to study the bonding properties between the coatings and the substrates. In vitro immersion tests were conducted to determine the corrosion behaviors of samples with and without deposit layers through electrochemical experiments. In the EPD process, the acetic acid content in the electrophoresis suspension and the electrophoretic voltage played important roles in improving the bonding properties, while the contents of chitosan (CS) and nano-hydroxyapatite (nHA, Ca10(PO4)6(OH)2) in the suspension had less significant influences on the mechanical bonding strength. It was observed that the coatings showed the excellent bonding property when an electrophoretic voltage was in a range of 40–110 V with other reagent amounts as follows: acetic acid: 4.5 vol.%, CS ≤ 0.25 g, nHA ≤ 2.0 g in 200 ml of a CS–acetic acid aqueous solution and nHA ≤ 2.5 g in 300 ml of absolute ethanol. The morphology of the composite coating obtained under the above optimal condition had a flake-like crystal structure. The EPD in the n

  10. Glasses, ceramics, and composites from lunar materials

    Science.gov (United States)

    Beall, George H.

    1992-02-01

    A variety of useful silicate materials can be synthesized from lunar rocks and soils. The simplest to manufacture are glasses and glass-ceramics. Glass fibers can be drawn from a variety of basaltic glasses. Glass articles formed from titania-rich basalts are capable of fine-grained internal crystallization, with resulting strength and abrasion resistance allowing their wide application in construction. Specialty glass-ceramics and fiber-reinforced composites would rely on chemical separation of magnesium silicates and aluminosilicates as well as oxides titania and alumina. Polycrystalline enstatite with induced lamellar twinning has high fracture toughness, while cordierite glass-ceramics combine excellent thermal shock resistance with high flexural strengths. If sapphire or rutile whiskers can be made, composites of even better mechanical properties are envisioned.

  11. Glasses, ceramics, and composites from lunar materials

    Science.gov (United States)

    Beall, George H.

    1992-01-01

    A variety of useful silicate materials can be synthesized from lunar rocks and soils. The simplest to manufacture are glasses and glass-ceramics. Glass fibers can be drawn from a variety of basaltic glasses. Glass articles formed from titania-rich basalts are capable of fine-grained internal crystallization, with resulting strength and abrasion resistance allowing their wide application in construction. Specialty glass-ceramics and fiber-reinforced composites would rely on chemical separation of magnesium silicates and aluminosilicates as well as oxides titania and alumina. Polycrystalline enstatite with induced lamellar twinning has high fracture toughness, while cordierite glass-ceramics combine excellent thermal shock resistance with high flexural strengths. If sapphire or rutile whiskers can be made, composites of even better mechanical properties are envisioned.

  12. Impact damage characterization of composite materials

    Science.gov (United States)

    Korkmaz, Yesim

    2002-04-01

    Impact damage in structural composites depends on their material properties, component geometry and a variety of impact parameters and experimental determination of their detailed characteristics requires prohibitively large test matrices. The effects of some of these parameters can be understood through simulation models that complement experimental results. In this dissertation a series of finite element models are developed using MSC/NASTRAN for calculating contact laws and progressive damage (e.g., matrix cracking, delamination and fiber break) in graphite/epoxy laminates subject to low and intermediate velocity impact. The validity of the computational models is supported by theoretical calculations involving idealized cases. The effects of laminate geometry as well as the impact parameters on the nature and degree of damage are studied. The global force-time and displacement-time responses of the laminate during impact are also studied. The results of this research can be used for damage growth prediction in composite structural components subject to impact loads.

  13. Characterization of nickel-doped biphasic calcium phosphate/graphene nanoplatelet composites for biomedical application

    Energy Technology Data Exchange (ETDEWEB)

    Baradaran, S., E-mail: saeid_baradaran@yahoo.com [Department of Mechanical Engineering, Faculty of Engineering, University of Malaya, 50603 Kuala Lumpur (Malaysia); Moghaddam, E. [Tropical Infectious Diseases Research and Education Centre, Department of Medical Microbiology, Faculty of Medicine, University of Malaya, 50603 Kuala Lumpur (Malaysia); Nasiri-Tabrizi, Bahman, E-mail: bahman_nasiri@hotmail.com [Advanced Materials Research Center, Materials Engineering Department, Najafabad Branch, Islamic Azad University, Isfahan (Iran, Islamic Republic of); Basirun, W.J. [Department of Chemistry, Faculty of Science, University of Malaya, Kuala Lumpur 50603 (Malaysia); Institute of Nanotechnology& Catalysis Research (NanoCat), University Malaya, 50603 Kuala Lumpur (Malaysia); Mehrali, M. [Department of Mechanical Engineering, Faculty of Engineering, University of Malaya, 50603 Kuala Lumpur (Malaysia); Department of Biomedical Engineering, Faculty of Engineering, University of Malaya, Kuala Lumpur 50603 (Malaysia); Sookhakian, M. [Department of Physics, Faculty of Science, University of Malaya, Kuala Lumpur 50603 (Malaysia); Hamdi, M. [Center of Advanced Manufacturing and Material Processing, University of Malaya, 50603 Kuala Lumpur (Malaysia); Alias, Y. [Department of Chemistry, Faculty of Science, University of Malaya, Kuala Lumpur 50603 (Malaysia)

    2015-04-01

    The effect of the addition of an ionic dopant to calcium phosphates for biomedical applications requires specific research due to the essential roles played in such processes. In the present study, the mechanical and biological properties of Ni-doped hydroxyapatite (HA) and Ni-doped HA mixed with graphene nanoplatelets (GNPs) were evaluated. Ni (3 wt.% and 6 wt.%)-doped HA was synthesized using a continuous precipitation method and calcined at 900 °C for 1 h. The GNP (0.5–2 wt.%)-reinforced 6% Ni-doped HA (Ni6) composite was prepared using rotary ball milling for 15 h. The sintering process was performed using hot isostatic pressing at processing conditions of 1150 °C and 160 MPa with a 1-h holding time. The results indicated that the phase compositions and structural features of the products were noticeably affected by the Ni and GNPs. The mechanical properties of Ni6 and 1.5Ni6 were increased by 55% and 75% in hardness, 59% and 163% in fracture toughness and 120% and 85% in elastic modulus compared with monolithic HA, respectively. The in-vitro biological behavior was investigated using h-FOB osteoblast cells in 1, 3 and 5 days of culture. Based on the osteoblast results, the cytotoxicity of the products was indeed affected by the Ni doping. In addition, the effect of GNPs on the growth and proliferation of osteoblast cells was investigated in Ni6 composites containing different ratios of GNPs, where 1.5 wt.% was the optimum value. - Highlights: • Ni doped biphasic calcium phosphate/graphene nanoplatelets composite was investigated. • Mechanical and biological properties were evaluated. • Phase compositions and structural features were influenced noticeably by the Ni and GNPs. • The cytotoxicity of the Ni was improved with the addition of GNPs.

  14. Characterization of nickel-doped biphasic calcium phosphate/graphene nanoplatelet composites for biomedical application

    International Nuclear Information System (INIS)

    The effect of the addition of an ionic dopant to calcium phosphates for biomedical applications requires specific research due to the essential roles played in such processes. In the present study, the mechanical and biological properties of Ni-doped hydroxyapatite (HA) and Ni-doped HA mixed with graphene nanoplatelets (GNPs) were evaluated. Ni (3 wt.% and 6 wt.%)-doped HA was synthesized using a continuous precipitation method and calcined at 900 °C for 1 h. The GNP (0.5–2 wt.%)-reinforced 6% Ni-doped HA (Ni6) composite was prepared using rotary ball milling for 15 h. The sintering process was performed using hot isostatic pressing at processing conditions of 1150 °C and 160 MPa with a 1-h holding time. The results indicated that the phase compositions and structural features of the products were noticeably affected by the Ni and GNPs. The mechanical properties of Ni6 and 1.5Ni6 were increased by 55% and 75% in hardness, 59% and 163% in fracture toughness and 120% and 85% in elastic modulus compared with monolithic HA, respectively. The in-vitro biological behavior was investigated using h-FOB osteoblast cells in 1, 3 and 5 days of culture. Based on the osteoblast results, the cytotoxicity of the products was indeed affected by the Ni doping. In addition, the effect of GNPs on the growth and proliferation of osteoblast cells was investigated in Ni6 composites containing different ratios of GNPs, where 1.5 wt.% was the optimum value. - Highlights: • Ni doped biphasic calcium phosphate/graphene nanoplatelets composite was investigated. • Mechanical and biological properties were evaluated. • Phase compositions and structural features were influenced noticeably by the Ni and GNPs. • The cytotoxicity of the Ni was improved with the addition of GNPs

  15. Evaluation of the effect of diet composition and B-group vitamins supplementation on selected calcium metabolism parameters in female rats

    Directory of Open Access Journals (Sweden)

    Joanna Sadowska

    2011-03-01

    Full Text Available Background. The aim of the study was to observe the effects of a modified diet, in which whole grains of cereals had been isocalorically substituted with wheat flour (type “500” and saccharose, and supplementation with B-group vitamins, on selected calcium metabolism parameters in female rats. Material and methods. The experiment was carried out on 36 female rats aged 6 months. Animals were fed two different diets. Groups I and II received clean tap water to drink, while group III had water solution of group-B vitamins. Results. An analysis of the outcomes of the diet modifications allowed concluding that the females fed on the modified feed, either supplemented or non-supplemented, excreted more calcium with urine and exhibited its lower concentrations in blood plasma, as compared with the females fed on the standard feed. No significant differences, however, were observed in plasma ionized calcium concentrations in the studied animals, which implies that the regulation mechanism of its bio-active form concentrations is preserved. It has been found that the applied supplementation of the modified diet promoted bone calcium release inducing plasma alkaline phosphatase activity in this group of animals. Supplementation was also accompanied by a shift in calcium distribution manifested by its increased concentrations in erythrocytes. Conclusions. Change in diet composition and supplementation were found to significantly affect calcium metabolism of the rats examined. Observed intracellular calcium accumulation may have been an underlying cause of an increased adipose tissue accumulation in B-group vitamin supplemented animals, which had been observed in previous studies.

  16. Characterization of material composite marble-polyester

    Directory of Open Access Journals (Sweden)

    Corpas, F. A.

    2002-12-01

    Full Text Available In this work we characterize a new material composite, formed with a polyester and crushed white marble mixture. The final purpose is double: to obtain a material for applications sufficiently competitive after an economic viability study, increasing the yield of the main commodity, using waste marble and improving the jobs in the quarries area. From the results obtained, we deduce then that this material could be used to inside and outside adornment.

    En este trabajo, caracterizamos un nuevo material compuesto, formado con una mezcla de poliéster y de mármol blanco triturado. El propósito final es doble: por un lado obtener un material para aplicaciones lo suficientemente competitivas como para que se pueda iniciar un estudio económico de viabilidad, aumentando el rendimiento de la materia prima y mejorando las salidas laborales de las comarcas extractoras. Para la caracterización del material se ha determinado el porcentaje adecuado de poliéster. Así como las propiedades mecánicas (flexión, compresión y dureza, químicas, fatiga térmica y su influencia a la exposición solar In order to characterized of material, we have determined the suitable porcentage of polyester Also we have carried out a study of the mechanical (stretching, resistance to traction, hardeness and thermal fatigue chemicals properties and solar radiation influence. De los resultados obtenidos, este material podría ser utilizado para ornamentación tanto de interior como de exterior.

  17. Application of reference point indentation for micro-mechanical surface characterization of calcium silicate based dental materials.

    Science.gov (United States)

    Antonijević, Djordje; Milovanović, Petar; Riedel, Christoph; Hahn, Michael; Amling, Michael; Busse, Björn; Djurić, Marija

    2016-04-01

    The objective of this study was to elucidate micromechanical properties of Biodentine and two experimental calcium silicate cements (CSCs) using Reference Point Indentation (RPI). Biomechanical characteristics of the cement type and the effects of a radiopacifier, liquid components, acid etching treatment and bioactivation in simulated body fluid (SBF) were investigated by measuring the microhardness, average unloading slope (Avg US) and indentation distance increase (IDI). Biodentine had a greater microhardness than the experimental CSCs, while the Avg US and IDI values were not significantly different among investigated materials. There was a statistically significant difference in microhardness and IDI values between pure CSCs and radiopacified cements (p < 0.05). Micromechanical properties were not affected by different liquid components used. Acid-etching treatment reduced Biodentine's microhardness while cements' immersion in SBF resulted in greater microhardness and higher IDI values compared to the control group. Clearly, the physiological environment and the cements' composition affect their surface micromechanical properties. The addition of calcium chloride and CSCs' immersion in SBF are beneficial for CSCs' micromechanical performance, while the addition of radiopacifiers and acid etching treatment weaken the CSCs' surface. Application of RPI aids with the characterization of micromechanical properties of synthetic materials' surfaces. PMID:26888441

  18. Hydroxyapatite-calcium sulfate-hyaluronic acid composite encapsulated with collagenase as bone substitute for alveolar bone regeneration.

    Science.gov (United States)

    Subramaniam, Sadhasivam; Fang, Yen-Hsin; Sivasubramanian, Savitha; Lin, Feng-Huei; Lin, Chun-pin

    2016-01-01

    Periodontitis is a very severe inflammatory condition of the periodontium that progressively damages the soft tissue and destroys the alveolar bone that supports the teeth. The bone loss is naturally irreversible because of limited reparability of the teeth. Advancement in tissue engineering provides an effective regeneration of osseous defects with suitable dental implants or tissue-engineered constructs. This study reports a hydroxyapatite, calcium sulfate hemihydrate and hyaluronic acid laden collagenase (HAP/CS/HA-Col) as a bone substitute for the alveolar bone regeneration. The composite material was mechanically tested and the biocompatibility was evaluated by WST-1 assay. The in vivo bone formation was assessed in rat with alveolar bone defects and the bone augmentation by the HAP/CS/HA-Col composite was confirmed by micro-CT images and histological examination. The mechanical strength of 6.69 MPa with excellent biocompatibility was obtained for the HAP/CS/HA-Col composite. The collagenase release profile had facilitated the acceleration of bone remodeling process and it was confirmed by the findings of micro-CT and H&E staining. The bone defects implanted with HAP/CS/HA composite containing 2 mg/mL type I collagenase have shown improved new bone formation with matured bone morphology in comparison with the HAP/CS/HA composite that lacks the collagenase and the porous hydroxyapatite (p-HAP) granules. The said findings demonstrated that the collagenase inclusion in HAP/CS/HA composite is a feasible approach for the alveolar bone regeneration and the same design can also be applied to other defective tissues. PMID:26454048

  19. Ceramic nanostructure materials, membranes and composite layers

    OpenAIRE

    Burggraaf, A.J.; Keizer, K.; Hassel, van, E Edwin

    1989-01-01

    Synthesis methods to obtain nanoscale materials will be briefly discussed with a focus on sol-gel methods. Three types of nanoscale composites (powders, membranes and ion implanted layers) will be discussed and exemplified with recent original research results. Ceramic membranes with a thickness of 1–10 μm consist of a packing of elementary particles with a size of 3–7 nm. The mean pore size is about 2.5–3 nm. The preparation routes are based on sol and sol-gel technologies. The pores can be ...

  20. HPC in Computational Micromechanics of Composite Materials

    Czech Academy of Sciences Publication Activity Database

    Blaheta, Radim; Kolcun, Alexej; Jakl, Ondřej; Souček, Kamil; Starý, Jiří; Georgiev, J.

    Madrid: Computer Architecture,Communications, and Systems Group (ARCOS), 2015 - (Carretero, J.; Blas, J.; Wyrzykowski, R.; Jeannot, E.), s. 143-146 ISBN 978-84-608-2581-4. [NESUS 2015- International Workshop on Sustainable Ultrascale Computing Systems /2./. Krakov (PL), 10.09.2015-11.09.2015] R&D Projects: GA MŠk ED1.1.00/02.0070 Institutional support: RVO:68145535 Keywords : computational micromechanics * HPC * composite materials Subject RIV: BA - General Mathematics https://www.dropbox.com/s/31ksrifeph9gen7/second-nesus-workshop_krakow2015.pdf

  1. Micromechanical models for graded composite materials

    DEFF Research Database (Denmark)

    Reiter, T; Dvorak, G.J.; Tvergaard, Viggo

    1997-01-01

    and local fields are predicted by Mori-Tanaka estimates. On the other hand, the response of graded materials with a skeletal microstructure in a wide transition zone between clearly defined matrix phases is better approximated by the self-consistent estimates. Certain exceptions are noted for loading...... by overall transverse shear stress; The results suggest that the averaging methods originally developed for statistically homogeneous aggregates may be selectively applied, with a reasonable degree of confidence, to aggregates dth composition gradients, subjected to both uniform and nonuniform...

  2. Composition, structure and properties of sputter deposited calcium phosphate thin films

    International Nuclear Information System (INIS)

    , chemically and in terms of surface microstructure. In addition, in-vitro bioactivity screening based on exposure to simulated body fluid (SBF) has been carried out. Furthermore, the effects of changing the target material and the repeated use of a single target over several sequential sputter runs were investigated to determine their influence on the properties of the resultant coatings. The analytical methods utilised included a number of well -established techniques, namely, Fourier Transform Infrared Spectroscopy (FTIR), X-ray Diffraction (XRD), Scanning Electron Microscopy (SEM), Energy Dispersive X-ray analysis (EDX) and Thermal Gravimetric Analysis (TGA). Additionally, advanced surface analytical techniques such as, Atomic Force Microscopy (AFM), X-ray Photoelectron Spectroscopy (XPS) and Time-of-Flight Secondary Ion Mass Spectrometry (ToFSIMS) were also used extensively. On the basis of the studies carried out here it can be concluded that the chemical and phase composition of the commercially available Ca-P materials are not always exactly as specified. Moreover, it has been shown that thermal processing can provide materials with more stable chemical properties. In the case of the laboratory synthesised systems, such thermal conditioning can be used to good effect to produce highly crystalline Ca-P bioceramics. However, under the current conditions employed, these systems are not normally phase pure. Notwithstanding this latter observation, it has been shown that the microwave-assisted synthesis is a quick and efficient method for producing Ca-P materials, which can be scaled up quite easily to produce greater yields. It therefore offers significant advantages over traditional wet precipitation techniques used to produce HA. Deposition of these materials at low deposition powers produces Ca-P coatings, which are both amorphous and calcium rich, as expected. In comparison the plasma sprayed layers show HA characteristics and possibly trace amounts of CaCo3, most

  3. A construction of novel iron-foam-based calcium phosphate/chitosan coating biodegradable scaffold material.

    Science.gov (United States)

    Wen, Zhaohui; Zhang, Liming; Chen, Chao; Liu, Yibo; Wu, Changjun; Dai, Changsong

    2013-04-01

    Slow corrosion rate and poor bioactivity restrict iron-based implants in biomedical application. In this study, we design a new iron-foam-based calcium phosphate/chitosan coating biodegradable composites offering a priority mechanical and bioactive property for bone tissue engineering through electrophoretic deposition (EPD) followed by a conversion process into a phosphate buffer solution (PBS). Tensile test results showed that the mechanical property of iron foam could be regulated through altering the construction of polyurethane foam. The priority coatings were deposited from 40% nano hydroxyapatite (nHA)/ethanol suspension mixed with 60% nHA/chitosan-acetic acid aqueous solution. In vitro immersion test showed that oxidation-iron foam as the matrix decreased the amount of iron implanted and had not influence on the bioactivity of this implant, obviously. So, this method could also be a promising method for the preparation of a new calcium phosphate/chitosan coating on foam construction. PMID:23827538

  4. Composite Material Suitable for Use as Electrode Material in a SOC

    DEFF Research Database (Denmark)

    2010-01-01

    The present invention relates to composite material suitable for use as an electrode material in a solid oxide cell, said composite material consist of at least two non-miscible mixed ionic and electronic conductors. Further provided is a composite material suitable for use as an electrode materi...

  5. Correlation between Composition and Properties of Composite Material Based on Scrap Tires

    OpenAIRE

    Mālers, L; Plēsuma, R; Ločmele, L; Kalniņš, M

    2010-01-01

    Purpose of present work is to investigate mechanical and insulation properties of the composite material based on scrap tires and polyurethane-type binder in correlation with composition of composite material. The studies of material’s hardness must be considered as an express-method for estimation of the selected mechanical properties (E and ccompressive stress) of the composite material without direct experimental testing of given parameters. It was shown that composite material must be r...

  6. Piezoelectric Nanoparticle-Polymer Composite Materials

    Science.gov (United States)

    McCall, William Ray

    Herein we demonstrate that efficient piezoelectric nanoparticle-polymer composite materials can be synthesized and fabricated into complex microstructures using sugar-templating methods or optical printing techniques. Stretchable foams with excellent tunable piezoelectric properties are created by incorporating sugar grains directly into polydimethylsiloxane (PDMS) mixtures containing barium titanate (BaTiO3 -- BTO) nanoparticles and carbon nanotubes (CNTs), followed by removal of the sugar after polymer curing. Porosities and elasticity are tuned by simply adjusting the sugar/polymer mass ratio and the electrical performance of the foams showed a direct relationship between porosity and the piezoelectric outputs. User defined 2D and 3D optically printed piezoelectric microstructures are also fabricated by incorporating BTO nanoparticles into photoliable polymer solutions such as polyethylene glycol diacrylate (PEGDA) and exposing to digital optical masks that can be dynamically altered. Mechanical-to-electrical conversion efficiency of the optically printed composite is enhanced by chemically altering the surface of the BTO nanoparticles with acrylate groups which form direct covalent linkages with the polymer matrix under light exposure. Both of these novel materials should find exciting uses in a variety of applications including energy scavenging platforms, nano- and microelectromechanical systems (NEMS/MEMS), sensors, and acoustic actuators.

  7. Radiation Facilities for Composite Materials Formation

    Science.gov (United States)

    Popov, G. F.; Zalubovsky, I. I.; Avilov, A. M.; Rudychev, V. G.

    1997-05-01

    The radiation facilities on the base of linac for polymer composite materials (PCM) formation was designed. The general technological scheme of PCM production consists in impregnations by synthetic monomers or oligomers of wares made of capillaryporous materials such as wood, qypsum, concrete, ceramic, paper, waste of papermaking, textile and woodworking production which are further treated by relativistic electron or breamsstruhglung beams. The facilities encorporates a linac with scanning electron beams, microwave chamber for drying of materials, a system for vacuum impregnating of materials with synthetic origomers, test bench for irradiations of samples, precise monitoring system for measuring of three-dimentional dose distribution in irradiated samples, and control processing system. The main beam parameters of linac are: electron energy 5--8 MeV; mean beam power up to 5 kW, pulse duration 1--4 mcs; scanning frequency of electromagnetic scanner 1--8 Hz; the irradiation is possible both with electron and with breamsstrahglung beams. The facilities were used for radiation processing investigation and production of new high-strength and corrosian-resistant PCM.

  8. Cell response of calcium phosphate based ceramics, a bone substitute material

    Directory of Open Access Journals (Sweden)

    Juliana Marchi

    2013-01-01

    Full Text Available The aim of this study was to characterize calcium phosphate ceramics with different Ca/P ratios and evaluate cell response of these materials for use as a bone substitute. Bioceramics consisting of mixtures of hydroxyapatite (HAp and β-tricalcium phosphate (β-TCP powders in different proportions were pressed and sintered. The physical and chemical properties of these bioceramics were then characterized. Characterization of the biological properties of these materials was based on analysis of cell response using cultured fibroblasts. The number of cells attached to the samples was counted from SEM images of samples exposed to cell culture solution for different periods. These data were compared by analysis of variance (ANOVA complemented by the Tukey's test. The TCP sample had higher surface roughness and lower density. The adherence and growth of FMM1 cells on samples from all groups was studied. Even though the different calcium based ceramics exhibited properties which made them suitable as bone substitutes, those with higher levels of β-TCP revealed improved cell growth on their surfaces. These observations indicated two-phase calcium phosphate based materials with a β-TCP surface layer to be a promising bone substitute.

  9. Implementation and use of composite materials in Fedem

    OpenAIRE

    Tyldum, Tor Helge

    2010-01-01

    The main goal of this master thesis was to implement composite materials in the analyzing software Fedem. Composite materials have become much used materials for various applications; they are used in everything from windmill blades and offshore diving life boats to sporting equipment.Because of the increasing use of composite materials Fedem Technology AS analyses more and more mechanisms containing parts made from these materials. They therefore wanted to implement an element in Fedem that ...

  10. Scale effects in tribological properties of solid-lubricating composites made of ultra-high molecular weight polyethylene filled with calcium stearate particles

    Science.gov (United States)

    Lurie, S. A.; Volkov-Bogorodskiy, D. B.; Knyzeva, A. G.; Panin, S. V.; Kornienko, L. A.

    2016-04-01

    Friction properties being influenced by scale effects are simulated in the paper by the example of polymer composite material made from Ultra High-Molecular Weight Polyethylenes (UHMWPE) filled by calcium stearate (C36H70CaO4). Of interest are the composites whose mechanical properties and tribotechnical characteristics do not depend monotonically on filler (inclusions) weight fraction. In order to describe the influence of scale effects onto frictional properties the model based on Reiss averaging (model of "weak phase") is employed. It is also suggested that when gradient elasticity theory is applicable the formal analogy between effective friction coefficient for surface heterogeneous structures and effective mechanical properties (compliances) for heterogeneous material can take place. Theoretical dependence to describe nonmonotonic change of effective friction coefficient versus filler concentration was obtained for the polymer composites under study. The suggested expressions might be useful for the sake of properties prognosis of antifriction polymeric materilas.

  11. SEPARATION OF WATER VAPORS FROM AIR BY SORPTION ON SOME COMPOSITE MATERIALS

    Directory of Open Access Journals (Sweden)

    OANA HAUTĂ

    2014-01-01

    Full Text Available This work presents an experimental investigation of the kinetics of water vapor sorption on two composites synthesized by impregnating activated carbon and activated alumina respectively with lithium bromide (named as MCA2 and MCC2 respectively. The obtained results showed an increase in water amount adsorbed on both composite materials. Due to different chemical natures of the host matrices, the water sorption kinetics on MCC2 is faster compared to that of MCA2. The presence of calcium chloride instead of lithium bromide in alumina pores will determine a shorter breakthrough time and a higher adsorption rate of water vapors.

  12. Fine-Tuning of Polymeric Resins and their Interfaces with Amorphous Calcium Phosphate. A Strategy for Designing Effective Remineralizing Dental Composites

    Directory of Open Access Journals (Sweden)

    Drago Skrtic

    2010-09-01

    Full Text Available For over a decade our group has been designing, preparing and evaluating bioactive, remineralizing composites based on amorphous calcium phosphate (ACP fillers embedded in polymerized methacrylate resin matrices. In these studies a major focus has been on exploring structure-property relationships of the matrix phase of these composites on their anti-cariogenic potential. The main challenges were to gain a better understanding of polymer matrix/filler interfacial properties through controlling the surface properties of the fillers or through fine-tuning of the resin matrix. In this work, we describe the effect of chemical structure and composition of the resin matrices on some of the critical physicochemical properties of the copolymers and their ACP composites. Such structure-property studies are essential in formulating clinically effective products, and this knowledge base is likely to have strong impact on the future design of therapeutic materials, appropriate for mineral restoration in defective tooth structures.

  13. Modulating calcium phosphate formation using CO2 laser engineering of a polymeric material

    International Nuclear Information System (INIS)

    The use of simulated body fluid (SBF) is widely used as a screening technique to assess the ability of materials to promote calcium phosphate formation. This paper details the use of CO2 laser surface treatment of nylon® 6,6 to modulate calcium phosphate formation following immersion in SBF for 14 days. Through white light interferometry (WLI) it was determined that the laser surface processing gave rise to maximum Ra and Sa parameters of 1.3 and 4.4 μm, respectively. The use of X-ray photoelectron spectroscopy (XPS) enabled a maximum increase in surface oxygen content of 5.6%at. to be identified. The laser-induced surface modifications gave rise to a modulation in the wettability characteristics such that the contact angle, θ, decreased for the whole area processed samples, as expected, and increased for the patterned samples. The increase in θ can be attributed to a transition in wetting nature to a mixed-state wetting regime. It was seen for all samples that calcium phosphate formed on each surface following 14 days. The largest increase in mass, Δg, owed to calcium phosphate formation, was brought about by the whole area processed sample irradiated with a fluence of 51 J cm−2. No correlation between the calcium phosphate formation and the laser patterned surface properties was determined due to the likely affect of the mixed-state wetting regime. Strong correlations between θ, the surface energy parameters and the calcium phosphate formation for the whole area processed samples allow one to realize the potential for this surface treatment technique in predicting the bone forming ability of laser processed materials. - Highlights: ► Surface modifications brought about a modulation in the wetting of nylon 6,6. ► An increase in θ can be attributed to a mixed-state wetting regime. ► Laser surface treatment modulated the ability to promote apatite formation. ► Mixed-state wetting regime affected the promotion of uniform apatite formation. ► Method

  14. Aluminium composite materials for multichip modules

    International Nuclear Information System (INIS)

    This paper reports that, as a result of continued advances in microelectronics, packaging technologies have become ital to the success of advanced designs. Progress in this field has been driven by advances in active device technologies that have resulted in significant miniaturization, increased functional density, and higher operating frequencies. These developments have produced ever-increasing power densities requiring improve thermal management schemes. In particular, multichip modules (MCMs) present challenges because they contain several devices in close proximity. The alternatives to improve cooling schemes-higher junction temperatures and decreased reliability-are clearly unacceptable. Requirements for improved cooling are complicated further in avionics systems by the need to minimize system weight and in automotive systems by the need to provide protection from a more hostile environment while maintaining low cost. These needs are driving materials developments along a number of fonts, as reviewed in Carl Zweben's article in this issue. Unfortunately, no current-generation material can meet all of these challenges. The use of aluminum or copper results in unacceptable expansion stress on silicon- or gallium arsenide-based devices. Kovar is costly to manufacture in complex configurations and ins inherently poor in thermal conductivity. The Cu/W and Cu/Mo blends, either in the form of metallurgical or macroscopic composites, offer good thermal conductivity but are inherently heavy and are manufactured from expensive raw materials

  15. Composite materials from new textile technologies

    Directory of Open Access Journals (Sweden)

    Jiménez, M. A.

    1997-12-01

    Full Text Available The present paper describes in a general way the most important of the advanced textile technologies which are oriented to the manufacturing of organic matrix composite materials, the paper presents their applications and the possibilities of future development. The use of these advanced weaving techniques allows the production of near-net-shaped preforms, which results in important savings in processing costs; moreover, these textile processes offer the possibility of introducing out-of plane reinforcing fibres, so there is an important increment of the impact strength and the damage tolerance of the final material.

    En el presente artículo se describen, de forma genérica, las más importantes de las tejedurías avanzadas destinadas a la fabricación de materiales compuestos de matriz orgánica, presentándose sus aplicaciones y futuras posibilidades de desarrollo. La utilización de estos procesos de tejeduría avanzados permite la elaboración de preformas cercanas a la forma final de la pieza, lo que se traduce en importantes reducciones en los costes de fabricación; además, estos procesos textiles ofrecen la posibilidad de introducir fibras de refuerzo fuera del plano, aumentando de forma considerable la resistencia a impacto y la tolerancia al daño del material final.

  16. A Resorbable Calcium-Deficient Hydroxyapatite Hydrogel Composite for Osseous Regeneration

    Energy Technology Data Exchange (ETDEWEB)

    Hutchens, Stacy A [ORNL; O' Neill, Hugh Michael [ORNL; Benson, Roberto S. [University of Tennessee, Knoxville (UTK); Evans, Barbara R [ORNL; Rawn, Claudia J [ORNL

    2009-01-01

    It was previously discovered that the unique structure and chemistry of bacterial cellulose (BC) permits the formation of calcium-deficient hydroxyapatite (CdHAP) nanocrystallites under aqueous conditions at ambient pH and temperature. In this study, BC was chemically modified via a limited periodate oxidation reaction to render the composite degradable and thus more suitable for bone regeneration. While native BC does not degrade in mammalian systems, periodate oxidation yields dialdehyde cellulose which breaks down at physiological pH. The composite was characterized by tensile testing, X-ray diffraction, Fourier transform infrared spectroscopy, and scanning electron microscopy. X-ray diffraction showed that oxidized BC retains its structure and could biomimetically form CdHAP. Degradation behavior was analyzed by incubating the samples in simulated physiological fluid (pH 7.4) at 37 C under static and dynamic conditions. The oxidized BC and oxidized BC-CdHAP composites both lost significant mass after exposure to the simulated physiological environment. Examination of the incubation solutions by UV-Vis spectrophotometric analysis demonstrated that, while native BC released only small amounts of soluble cellulose fragments, oxidized cellulose releases carbonyl containing degradation products as well as soluble cellulose fragments. By entrapping CdHAP in a degradable hydrogel carrier, this composite should elicit bone regeneration then resorb over time to be replaced by new osseous tissue.

  17. Glass Composite Materials for Nuclear Waste Immobilisation

    International Nuclear Information System (INIS)

    Glass composite materials (GCM) are discussed as flexible waste forms for immobilising various types of wastes. Compared to homogeneous glassy materials, GCMs can incorporate larger amounts of toxic elements. GCMs can be produced at higher capacity and lower processing temperatures. In this work, simulated spent clinoptilolite was immobilised in a monolithic glass composite wasteform (GCM) produced by a pressureless sintering for 2 hours at relative low temperatures 750 degree C. The GCM utilises the high durability of alkali borosilicate glass to encapsulate the Cs-impregnated clinoptilolite (Cs-Clino). With this approach mobile radionuclides are retained by a multi-barrier system, comprising the crystalline form of the clinoptilolite and the borosilicate glass wastes loading ranging from 1:1 up to 1:10 glass to Cs-clino volume ratios corresponding to 37-88 mass % were studied. Water durability of GCM was assessed in 7 days leaching tests in deionised water at 40 degree C based on ASTM C1220-98 standard. It was found that the normalised leaching rates of Cs remain below 6.35 x 10-6g/cm2day in a GCM with 73 mass % waste during a leaching test for 7 days. However at higher waste loading of 80 mass % the normalised leaching rate of Cs was as high as 9.06 10-4g/cm2day. This drastic change can be explained by formation of clusters made of inter-connected clinoptilolite particle leading to percolation threshold phenomena. (Author)

  18. Glass composite materials for nuclear waste immobilisation

    International Nuclear Information System (INIS)

    Glass composite materials (GCM) are discussed as flexible waste forms for immobilising various types of wastes. Compared to homogeneous glassy materials, GCMs can incorporate larger amounts of toxic elements. GCMs can be produced at higher capacity and lower processing temperatures. In this work, simulated spent clinoptilolite was immobilised in a monolithic glass composite wasteform (GCM) produced by a pressureless sintering for 2 hours at relative low temperatures 750 degree Celsius. The GCM utilises the high durability of alkali borosilicate glass to encapsulate the Cs-impregnated clinoptilolite (Cs-Clino). With this approach mobile radionuclides are retained by a multi-barrier system, comprising the crystalline form of the clinoptilolite and the borosilicate glass. Wastes loading ranging from 1:1 up to 1:10 glass to Cs-clino volume ratios corresponding to 37-88 mass % were studied. Water durability of GCM was assessed in 7 days leaching tests in deionised water at 40 degree Celsius based on ASTM C1220-98 standard. It was found that the normalised leaching rates of Cs remain below 6.35 x 10-6g/ cm2 day in a GCM with 73 mass % waste during a leaching test for 7 days. However, at higher waste loading of ≥80 mass % the normalised leaching rate of Cs was as high as 9.06 x 10-4 g/ cm2 day. This drastic change can be explained by formation of clusters made of inter-connected clinoptilolite particle leading to percolation threshold phenomena. (author)

  19. Fabricating porous materials using interpenetrating inorganic-organic composite gels

    Energy Technology Data Exchange (ETDEWEB)

    Seo, Dong-Kyun; Volosin, Alex

    2016-06-14

    Porous materials are fabricated using interpenetrating inorganic-organic composite gels. A mixture or precursor solution including an inorganic gel precursor, an organic polymer gel precursor, and a solvent is treated to form an inorganic wet gel including the organic polymer gel precursor and the solvent. The inorganic wet gel is then treated to form a composite wet gel including an organic polymer network in the body of the inorganic wet gel, producing an interpenetrating inorganic-organic composite gel. The composite wet gel is dried to form a composite material including the organic polymer network and an inorganic network component. The composite material can be treated further to form a porous composite material, a porous polymer or polymer composite, a porous metal oxide, and other porous materials.

  20. Tension mechanical properties of recycled glass-epoxy composite material

    OpenAIRE

    Petrović Jelena M.; Ljubić Darko M.; Stamenović Marina R.; Dimić Ivana D.; Putić Slaviša S.

    2012-01-01

    The significance of composite materials and their applications are mainly due to their good properties. This imposes the need for their recycling, thus extending their lifetime. Once used composite material will be disposed as a waste at the end of it service life. After recycling, this kind of waste can be used as raw materials for the production of same material, which raises their applicability. This indicates a great importance of recycling as a method of the renowal of composite ma...

  1. Chitosan Derivatives/Calcium Carbonate Composite Capsules Prepared by the Layer-by-Layer Deposition Method

    Directory of Open Access Journals (Sweden)

    Kensuke Sakurai

    2008-03-01

    Full Text Available Core/shell capsules composed of calcium carbonate whisker core (rod-like shape and chitosan/chitosansulfate shell were prepared by the layer-by-layer deposition technique. Two chitosan samples of different molecular weights (Mw=9.7×104 and 1.09×106g·mol-1 were used as original materials. Hollow capsules were also obtained by dissolution of the core in hydrochloric acid. Electron microscopy revealed that the surface of the shell is rather ragged associated with some agglomerates. The shell thickness l obeys a linear relation with respect to the number of deposited layers m as l=md+a(a>0. The values of d (thickness per layer were 4.0 and 1.0 nm for the higher and lower Mw chitosan materials, respectively, both of which are greater than the thickness of the monolayer. The results suggest that the feature of the deposition does not obey an ideal homogeneous monolayer-by-monolayer deposition mechanism. Shell crosslinked capsules were also prepared via photodimerization reaction of cinnamoyl groups after a deposition of cinnamoyl chitosan to the calcium carbonate whisker core. The degree of crosslink was not enough to stabilize the shell structure, and hollow capsule was not obtained.

  2. Control of macroscopic characteristics of composite materials for radiation protection

    International Nuclear Information System (INIS)

    Composite materials, intended for radiation protection, were studied. They are made of polystyrene and reinforced by an aluminum. Aluminum is used as a powder. Tungsten powder was added for increase the radiation-protective properties. Examined the state of the composite material at different temperatures. The composite material is dependent on the component. Thermal conductivity of the composite material was studied. It was used in the form of balls and plates. The absorbed dose of gamma-radiation is calculated by mathematical methods. The area where the maximum absorbed gamma quanta found for composites

  3. Preparation of poly (methyl methacrylate)/nanometer calcium carbonate composite by in-situ emulsion polymerization

    Institute of Scientific and Technical Information of China (English)

    史建明; 包永忠; 黄志明; 翁志学

    2004-01-01

    Methyl methacrylate (MMA) emulsion polymerization in the presence of nanometer calcium carbonate (nano-CaCO3) surface modified with (-methacryloxypropyltrimethoxysilane (MPTMS) was carried out to prepare poly (methyl methacrylate) (PMMA)/nano-CaCO3 composite. The reaction between nano-CaCO3 and MPTMS, and the grafting of PMMA onto nano-CaCO3 were confirmed by infrared spectrum. The grafting ratio and grafting efficiency of PMMA on nano-CaCO3 modified with MPTMS were much higher than that on nano-CaCO3 modified with stearic acid. The grafting ratio of PMMA increased as the weight ratio between MMA and nano-CaCO3 increased, while the grafting efficiency of PMMA decreased. Transmission electron micrograph showed that nano-CaCO3 covered with PMMA was formed by in-situ emulsion polymerization.

  4. Electrodeposition of porous hydroxyapatite/calcium silicate composite coating on titanium for biomedical applications

    Energy Technology Data Exchange (ETDEWEB)

    Huang, Yong; Han, Shuguang [Institute of Life Science and Technology, University of Electronic Science and Technology of China, Chengdu 610054 (China); Pang, Xiaofeng, E-mail: pxf2012@yahoo.com.cn [Institute of Life Science and Technology, University of Electronic Science and Technology of China, Chengdu 610054 (China); International Centre for Materials Physics, Chinese Academy of Science, Shenyang 110015 (China); Ding, Qionqion; Yan, Yajing [Institute of Life Science and Technology, University of Electronic Science and Technology of China, Chengdu 610054 (China)

    2013-04-15

    A novel method of electrolytic porous hydroxyapatite/calcium silicate (HA/CaSiO{sub 3}) composite coating was conducted on pure titanium in a mixed solution of nano-SiO{sub 2}, Ca(NO{sub 3}){sub 2} and NH{sub 4}H{sub 2}PO{sub 4}. SEM observation showed that the composite layer was porous, thereby providing abundant sites for the osteoblast adhesion. XRD results showed that the composite coating was mainly composed of HA and CaSiO{sub 3}. Bond strength testing exhibited that HA-CaSiO{sub 3}/Ti had higher bond strength than HA/Ti. The HA/CaSiO{sub 3} coating was more corrosion resistant than the HA coating based on the polarization tests. In vitro cell experiments demonstrated that both the HA and HA/CaSiO{sub 3} coatings showed better cell response than the bared titanium. In addition, the proliferation of MC3T3-E1 osteoblast cells grown on the HA/CaSiO{sub 3} coating were remarkably higher than those on the bared Ti and pure HA coating.

  5. Electrodeposition of porous hydroxyapatite/calcium silicate composite coating on titanium for biomedical applications

    Science.gov (United States)

    Huang, Yong; Han, Shuguang; Pang, Xiaofeng; Ding, Qionqion; Yan, Yajing

    2013-04-01

    A novel method of electrolytic porous hydroxyapatite/calcium silicate (HA/CaSiO3) composite coating was conducted on pure titanium in a mixed solution of nano-SiO2, Ca(NO3)2 and NH4H2PO4. SEM observation showed that the composite layer was porous, thereby providing abundant sites for the osteoblast adhesion. XRD results showed that the composite coating was mainly composed of HA and CaSiO3. Bond strength testing exhibited that HA-CaSiO3/Ti had higher bond strength than HA/Ti. The HA/CaSiO3 coating was more corrosion resistant than the HA coating based on the polarization tests. In vitro cell experiments demonstrated that both the HA and HA/CaSiO3 coatings showed better cell response than the bared titanium. In addition, the proliferation of MC3T3-E1 osteoblast cells grown on the HA/CaSiO3 coating were remarkably higher than those on the bared Ti and pure HA coating.

  6. A Novel Injectable Magnesium/Calcium Sulfate Hemihydrate Composite Cement for Bone Regeneration

    Directory of Open Access Journals (Sweden)

    Shanchuan Zhang

    2015-01-01

    Full Text Available Objective. A novel injectable magnesium/calcium sulfate hemihydrate (Mg/CSH composite with improved properties was reported here. Methods. Composition, setting time, injectability, compressive strength, and bioactivity in simulated body fluid (SBF of the Mg/CSH composite were evaluated. Furthermore, the cellular responses of canine bone marrow stromal cells (cBMSCs and bone formation capacity after the implantation of Mg/CSH in tibia defects of canine were investigated. Results. Mg/CSH possessed a prolonged setting time and markedly improved injectability and mechanical property p<0.05. Mg/CSH samples showed better degradability than CSH in SBF after 21 days of soaking p<0.05. Moreover, the degrees of cell attachment, proliferation, and capability of osteogenic differentiation on the Mg/CSH specimens were higher than those on CSH, without significant cytotoxicity and with the increased proliferation index, ALP activity, and expression levels of integrin β1 and Coll I in cBMSCs p<0.05. Mg/CSH enhanced the efficiency of new bone formation at the tibia defect area, including the significantly elevated bone mineral density, bone area fraction, and Coll I expression level p<0.05. Conclusions. The results implied that this new injectable bone scaffold exhibited promising prospects for bone repair and had a great potential in bone tissue engineering.

  7. Electrodeposition of porous hydroxyapatite/calcium silicate composite coating on titanium for biomedical applications

    International Nuclear Information System (INIS)

    A novel method of electrolytic porous hydroxyapatite/calcium silicate (HA/CaSiO3) composite coating was conducted on pure titanium in a mixed solution of nano-SiO2, Ca(NO3)2 and NH4H2PO4. SEM observation showed that the composite layer was porous, thereby providing abundant sites for the osteoblast adhesion. XRD results showed that the composite coating was mainly composed of HA and CaSiO3. Bond strength testing exhibited that HA-CaSiO3/Ti had higher bond strength than HA/Ti. The HA/CaSiO3 coating was more corrosion resistant than the HA coating based on the polarization tests. In vitro cell experiments demonstrated that both the HA and HA/CaSiO3 coatings showed better cell response than the bared titanium. In addition, the proliferation of MC3T3-E1 osteoblast cells grown on the HA/CaSiO3 coating were remarkably higher than those on the bared Ti and pure HA coating.

  8. The Calcium Phosphate Matrix of FGF-2-Apatite Composite Layers Contributes to Their Biological Effects

    Directory of Open Access Journals (Sweden)

    Hirotaka Mutsuzaki

    2014-06-01

    Full Text Available The purpose of the present study was to fabricate fibroblast growth factor (FGF-2-apatite composite layers on titanium (Ti pins in one step at 25 °C using a supersaturated calcium phosphate (CaP solution, and to evaluate the physicochemical characteristics and biological effects of the coated Ti pins compared with coated Ti pins fabricated at 37 °C. Ti pins were immersed in a supersaturated CaP solution containing 0.5, 1.0, or 2.0 µg/mL FGF-2 at 25 °C for 24 h (25F0.5, 25F1.0, and 25F2.0 or containing 4.0 µg/mL FGF-2 at 37 °C for 48 h (37F4.0. Except for the 25F0.5, the chemical compositions and the mitogenic activity levels of FGF-2 of the composite layers formed by these two methods were similar, except for the Ca/P molar ratio, which was markedly smaller at 25 °C (1.55–1.56 ± 0.01–0.02, p = 0.0008–0.0045 than at 37 °C (1.67 ± 0.11. Thus, either the apatite was less mature or the amount of amorphous calcium phosphate was higher in the composite layer formed at 25 °C. In vivo, the pin tract infection rate by visual inspection for 37F4.0 (45% was lower than that for 25F1.0 (80%, p = 0.0213, and the rate of osteomyelitis for 37F4.0 (35% was lower than that for 25F0.5 (75%, p = 0.0341. The extraction torque for 37F4.0 (0.276 ± 0.117 Nm was higher than that for 25F0.5 (0.192 ± 0.117 Nm, p = 0.0142 and that for 25F1.0 (0.176 ± 0.133 Nm, p = 0.0079. The invasion rate of S. aureus for 37F4.0 (35% was lower than that for 25F0.5 (75%, p = 0.0110. On the whole, the FGF-2-apatite composite layer formed at 25 °C tended to be less effective at improving fixation strength in the bone-pin interface and resisting pin tract infections. These results suggest that the chemistry of the calcium phosphate matrix that embeds FGF-2, in addition to FGF-2 content and activity, has a significant impact on composite infection resistance and fixation strength.

  9. Preparation of mesoporous carbon/polypyrrole composite materials and their supercapacitive properties

    Directory of Open Access Journals (Sweden)

    WU-JUN ZOU

    2011-08-01

    Full Text Available We synthesized mesoporous carbons/polypyrrole composites, using a chemical oxidative polymerization and calcium carbonate as a sacrificial template. N2 adsorption-desorption method, Fourier infrared spectroscopy, and transmission electron microscopy were used to characterize the structure and morphology of the composites. The measurement results indicated that as-synthesized carbon with the disordered mesoporous structure and a pore size of approximately 5 nm was uniformly coated by polypyrrole. The electrochemical behavior of the resulting composite was examined by cyclic voltammetry and cycle life measurements, and the obtained results showed that the specific capacitance of the resulting composite electrode was as high as 313 F g−1, nearly twice the capacitance of pure mesoporous carbon electrode (163 F g–1. This reveals that the electrochemical performance of these materials is governed by a combination of the electric double layer capacitance of mesoporous carbon and pseudocapacitance of polypyrrole.

  10. Compaction of functionalized calcium carbonate, a porous and crystalline microparticulate material with a lamellar surface.

    Science.gov (United States)

    Stirnimann, Tanja; Atria, Susanna; Schoelkopf, Joachim; Gane, Patrick A C; Alles, Rainer; Huwyler, Jörg; Puchkov, Maxim

    2014-05-15

    In the present study, we aimed to characterize the compressibility and compactibility of the novel pharmaceutical excipient, functionalized calcium carbonate (FCC). We studied three FCC modifications and compared the values for compressibility and compactibility with mannitol, microcrystalline cellulose (MCC), and ground calcium carbonate (CC 330) as well as mixtures of paracetamol and MCC or FCC at drug loads of 0%, 25%, 50%, 75%, and 100% (w/w). We used Heckel analysis, modified Heckel analysis, and Leuenberger analysis to characterize the compaction and compression behavior of the mixtures. Compaction analysis of FCC showed this material to markedly differ from ground calcium carbonate, exhibiting properties, i.e. plastic deformability, similar to those of MCC. This effect was attributed to the highly lamellar structure of FCC particles whose thickness is of the order of a single crystal unit cell. According to Leuenberger parameters, we concluded that FCC-based tablet formulations had mechanical properties equal or superior to those formulated with MCC. FCC tablets with high tensile strength were obtained already at low compressive pressures. Owing to these favorable properties (i.e. marked tensile strength and porosity), FCC promises to be suitable for the preparation of solid dosage forms. PMID:24631309

  11. Calcium montmorillonite clay in dairy feed reduces aflatoxin concentrations in milk without interfering with milk quality, composition or yield

    Science.gov (United States)

    This study was designed to determine if a calcium montmorillonite clay (Novasil Plus, NSP), can significantly reduce aflatoxin M1 (AFM1) concentrations in milk without affecting dry matter intake (DMI), milk yield, milk composition, vitamin A, or riboflavin concentrations. The study was designed us...

  12. Numerical simulation of mechanical behavior of composite materials

    CERN Document Server

    Oller, Sergio

    2014-01-01

    An original mechanical formulation to treat nonlinear orthotropic behavior of composite materials is presented in this book. It also examines different formulations that allow us to evaluate the behavior of composite materials through the composition of its components, obtaining a new composite material. Also two multiple scale homogenization methods are given, one based on the analytical study of the cells (Ad-hoc homogenization), and other one, more general based on the finite element procedure applied on the macro scale (upper-scale) and in the micro scale (sub-scale). A very general formulation to simulate the mechanical behavior for traditional composite structures (plywood, reinforced concrete, masonry, etc.), as well as the new composite materials reinforced with long and short fibers, nanotubes, etc., are also shown in this work. Typical phenomena occurring in composite materials are also described in this work, including fiber-matrix debounding, local buckling of fibers and its coupling with the over...

  13. In-situ high temperature XRD of calcium phosphate biomaterial using DEHPA as the starting material

    International Nuclear Information System (INIS)

    A process to produce calcium phosphate biomaterial was done using an organic based phosphoric acid (DEHPA) as its starting material. The gel obtained from this reaction was used to study calcium phosphate transformation using in-situ XRD with temperature ranges from room temperature to 1300 degree C. The results obtained from this analysis show the following phase transformation: Gel β-Ca2P2O7 β-TCP + HA α-TCP + HA, β-Ca2P2O7 forms at 400 degree C and as we heat the sample at 1000 degree C peaks belonging to β- TCP and HA appears showing the transformation of the β-Ca2P2O7 phase. When the sample is heated up further to 1200 degree C, β-TCP is transform into α-TCP. In the cold in-situ study, XRD analysis was performed on the sample from room temperature to -140 degree C. At room the XRD diffractogram shows the sample as an amorphous material and as the temperature was further lowered sharp peaks begins to form indicating that the material had becomes crystalline. The peaks were identified to be that calcium hydrogen phosphate (Ca(H2PO4)2) and this indicates that there is no hydroxyl group removal during the cooling process. The relative crystallinity values obtained for the different cooling temperatures show a slow exponential increase on the initial cooling of 0 to -100 degree C and at further cooling temperatures resulted fast and linear process. Also unlike the in-situ XRD analysis performs at high temperature no phase transformation occurred at this low temperature. (Author)

  14. Irradiation behavior of carbon-based composite materials

    International Nuclear Information System (INIS)

    Consideration is given to the data on radiation changes of sizes and some properties of different carbon-based composite materials (carbon-graphite and graphite-graphite compositions; carbon-carbon composite materials with carbon reinforcing fibers; carbon-silicon compositions), irradiated by neutrons at 320-1700 k. It is shown that change of sizes is dictated by the type and the ratio of components, forming (or not forming) the reinforcing uniform frame. 22 refs.; 10 figs

  15. Using of Composite Material in Wind Turbine Blades

    OpenAIRE

    Bulent Eker; Aysegul Akdogan; Ali Vardar

    2006-01-01

    The turbines manufactured from the mid 1980s until the late 1990s were mainly constructed using standard components. After that period, special components started being designed and manufactured for turbine use only. One of the best solutions is using composite materials in wind turbine. Most composites are made up of just two materials. One material (the matrix or binder) binds together a cluster of fibers or the fragments of a much stronger material and the second material (the reinforcemen...

  16. Glass matrix composite material prepared with waste foundry sand

    Institute of Scientific and Technical Information of China (English)

    ZHANG Zhao-shu; XIA Ju-pei; ZHU Xiao-qin; LIU Fan; HE Mao-yun

    2006-01-01

    The technology of glass matrix of the composite material manufactured through a sintering process and using waste foundry sand and waste glass as the main raw materials was studied. The effects of technological factors on the performance of this material were studied. The results showed that this composite material is formed with glass as matrix, core particulate as strengthening material, it has the performance of glass and ceramics, and could be used to substitute for stone.

  17. Oxygen isotope composition of trinitite postdetonation materials.

    Science.gov (United States)

    Koeman, Elizabeth C; Simonetti, Antonio; Chen, Wei; Burns, Peter C

    2013-12-17

    Trinitite is the melt glass produced subsequent the first nuclear bomb test conducted on July 16, 1945, at White Sands Range (Alamagordo, NM). The geological background of the latter consists of arkosic sand that was fused with radioactive debris and anthropogenic materials at ground zero subsequent detonation of the device. Postdetonation materials from historic nuclear weapon test sites provide ideal samples for development of novel forensic methods for attribution and studying the chemical/isotopic effects of the explosion on the natural geological environment. In particular, the latter effects can be evaluated relative to their spatial distribution from ground zero. We report here δ(18)O(‰) values for nonmelted, precursor minerals phases (quartz, feldspar, calcite), "feldspathic-rich" glass, "average" melt glass, and bulk (natural) unmelted sand from the Trinity site. Prior to oxygen isotope analysis, grains/crystals were examined using scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDS) to determine their corresponding major element composition. δ(18)O values for bulk trinitite samples exhibit a large range (11.2-15.5‰) and do not correlate with activity levels for activation product (152)Eu; the latter levels are a function of their spatial distribution relative to ground zero. Therefore, the slow neutron flux associated with the nuclear explosion did not perturb the (18)O/(16)O isotope systematics. The oxygen isotope values do correlate with the abundances of major elements derived from precursor minerals present within the arkosic sand. Hence, the O isotope ratios documented here for trinitite melt glass can be attributed to a mixture of the respective signatures for precursor minerals at the Trinity site prior to the nuclear explosion. PMID:24304329

  18. Quasimolecular Dynamic Simulation for Bending Fracture of Laminar Composite Materials

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    Recently, quasimolecular dynamics has been successfully used to simulate the deformation characteristics of actual size solid materials. In quasimolecular dynamics, which is an attempt to bridge the gap between atomistic and continuum simulations, molecules are aggregated into large units, called quasimolecules, to evaluate large scale material behavior. In this paper, a 2-dimensional numerical simulation using quasimolecular dynamics was performed to investigate laminar composite material fractures and crack propagation behavior in the uniform bending of laminar composite materials. It was verified that under bending deformation laminar composite materials deform quite differently from homogeneous materials

  19. Polymer composite material structures comprising carbon based conductive loads

    OpenAIRE

    Jérôme, Robert; Pagnoulle, Christophe; Detrembleur, Christophe; Thomassin, Jean-Michel; Huynen, Isabelle; Bailly, Christian; Bednarz, Luikasz; Daussin, Raphaël; Saib, Aimad; Baudouin, Anne-Christine; Laloyaux, Xavier

    2007-01-01

    The present invention provides a polymer composite material structure comprising at least one layer of a foamed polymer composite material comprising a foamed polymer matrix and 0.1 wt % to 6 wt % carbon based conductive loads, such as e.g. carbon nanotubes, dispersed in the foamed polymer matrix. The polymer composite material structure according to embodiments of the present invention shows good shielding and absorbing properties notwithstanding the low amount of carbon based conductive loa...

  20. Polymer composite material structures comprising carbon based conductive loads

    OpenAIRE

    Jérôme, Robert; Pagnoulle, Christophe; Detrembleur, Christophe; Thomassin, Jean-Michel; Huynen, Isabelle; Bailly, Christian; Bednarz, Lucasz; Daussin, Raphaël; Saib, Aimad

    2006-01-01

    The present invention provides a polymer composite material structure comprising at least one layer of a foamed polymer composite material comprising a foamed polymer matrix and 0.1 to 6 wt% carbon based conductive loads, such as e.g. carbon nanotubes, dispersed in the foamed polymer matrix. The polymer composite material structure according to embodiments of the present invention shows good shielding and absorbing properties notwithstanding the low amount of carbon based conductive loads. Th...

  1. Radioactive emissions study in radioluminescent composite materials

    International Nuclear Information System (INIS)

    In the present paper we analyze radioactive emissions from the selfradiolytical processes in radioluminescent composite materials based on tritium labeled polymers. We studied tritium labelled siloxanic polymers obtained by hydrolysis of: ethyl-T2-SiCl3+SiCl4; ethyl-T2-SiCl3+phenyl-SiCl3+SiCl4; ethyl-T2-SiCl3+phenyl-SiCl3; ethyl-T2-phenyl-SiCl2+SiCl4; propyl-T2-SiCl3+SiCl4; propyl-T2-SiCl3+phenyl-SiCl3+SiCl4; propyl-T2-SiCl3+phenyl-SiCl3; propyl-T2-phenyl-SiCl2+SiCl4 and tritiated oligomers 1,4-diphenyl-butane-T8; 1,4-diphenyl-2-butene-T6; 1,4-diphenyl-butadiene-T4, oligomers poly-1,4-diphenyl-butadiene. Radioactive emissions analysis was carried out by storage activity loss determination in conditions similar to those of radioluminescent pigments. The results obtained were compared with the results obtained by ESR spectroscopy on inactive polymeric structures and by quantum mechanical simulation. (authors)

  2. Multi-material Preforming of Structural Composites

    Energy Technology Data Exchange (ETDEWEB)

    Norris, Robert E. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Eberle, Cliff C. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Pastore, Christopher M. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Sudbury, Thomas Z. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Xiong, Fue [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Hartman, David [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

    2015-05-01

    Fiber-reinforced composites offer significant weight reduction potential, with glass fiber composites already widely adopted. Carbon fiber composites deliver the greatest performance benefits, but their high cost has inhibited widespread adoption. This project demonstrates that hybrid carbon-glass solutions can realize most of the benefits of carbon fiber composites at much lower cost. ORNL and Owens Corning Reinforcements along with program participants at the ORISE collaborated to demonstrate methods for produce hybrid composites along with techniques to predict performance and economic tradeoffs. These predictions were then verified in testing coupons and more complex demonstration articles.

  3. Non-Catalytic Self Healing Composite Material Solution Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Fiber reinforce polymer (FRP) composite materials are seeing increasing use in the construction of a wide variety of aerospace structures. However, uncertainties...

  4. Nanoscale calcium aluminate coated graphite for improved performance of alumina based monolithic refractory composite

    International Nuclear Information System (INIS)

    Graphical abstract: - Highlights: • Sol–gel Ca-doped γ-Al2O3 accomplished graphite retention. • Nanocoating considerably improved matrix-aggregate bonding. • Less porous simulated matrix upgraded slag resistance. - Abstract: The synthesis and properties of high alumina castable containing nanostructured calcium aluminate coated graphite were studied in terms of slag resistance and overall physical characteristics. Raman spectroscopy, BET surface area and field emission scanning electron microscopy (FESEM) were performed to exclusively understand the coating characteristics and its compatibility in refractory composite. The coating not only secured graphite in castable for prolonged period but also noticeably improved matrix to aggregate contact. The microstructural aspects of castables were investigated, with special emphasis on a representative matrix prepared and infiltrated with slag at elevated temperature. Scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS) of fired composite containing surface-treated graphite was quite prospective. It circumvented the problems of incorporating as-received graphite in castables and should be in the attention of refractory researchers and producers

  5. Nanoscale calcium aluminate coated graphite for improved performance of alumina based monolithic refractory composite

    Energy Technology Data Exchange (ETDEWEB)

    Mukhopadhyay, S., E-mail: msunanda_cct@yahoo.co.in

    2013-07-15

    Graphical abstract: - Highlights: • Sol–gel Ca-doped γ-Al{sub 2}O{sub 3} accomplished graphite retention. • Nanocoating considerably improved matrix-aggregate bonding. • Less porous simulated matrix upgraded slag resistance. - Abstract: The synthesis and properties of high alumina castable containing nanostructured calcium aluminate coated graphite were studied in terms of slag resistance and overall physical characteristics. Raman spectroscopy, BET surface area and field emission scanning electron microscopy (FESEM) were performed to exclusively understand the coating characteristics and its compatibility in refractory composite. The coating not only secured graphite in castable for prolonged period but also noticeably improved matrix to aggregate contact. The microstructural aspects of castables were investigated, with special emphasis on a representative matrix prepared and infiltrated with slag at elevated temperature. Scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS) of fired composite containing surface-treated graphite was quite prospective. It circumvented the problems of incorporating as-received graphite in castables and should be in the attention of refractory researchers and producers.

  6. Effects of Calcium on ATPase Activity and Lipid Composition of Plasma Membranes from Wheat Roots Under Aluminum Stress

    Institute of Scientific and Technical Information of China (English)

    HE Long-fei; SHEN Zhen-guo; LIU You-liang

    2003-01-01

    Effects of calcium on ATPase activities, lipid contents, and fatty acid compositions of plasma membrane from wheat roots were assayed under aluminum stress. The results showed that the increase of calcium concentration in the nutrient solution increased the activity of H+-ATPase and the phospholipid content, decreased the activity of Ca2+-ATPase and the galactolipid of plasma membrane. Owing to the decrease of linolenic acid content, the index of unsaturated fatty acid (IUFA) and index of double bond (DBI) decreased in Altas66. The IUFA and DBI of plasma membrane from Scout66 roots increased because its linolenic acid content increased obviously and its palmitic acid content decreased apparently.

  7. Advances in thermoplastic matrix composite materials

    Energy Technology Data Exchange (ETDEWEB)

    Newaz, G.M.

    1989-01-01

    Accounts are given of the development status of thermoplastic composite processing methods, as well as their current thermal and mechanical behavior and delamination properties. Attention is given to the thermoplastic coating of carbon fibers, pultrusion-process modeling, the high temperature behavior of graphite/PEEK, the thermal conductivity of composites for electronic packaging, a FEM analysis of mode I and II thermoplastic-matrix specimens, and reinforcements' resin-impregnation behavior during thermoplastic composite manufacture. Also discussed are the mechanical properties of carbon fiber/PEEK for structural applications, moisture-content mechanical property effects in PPS-matrix composites, the interlaminar fracture toughness of thermoplastic composites, and thermoplastic composite delamination growth under elevated temperature cyclic loading.

  8. In Vitro Cytotoxicity of Calcium Silicate-Based Endodontic Cement as Root-End Filling Materials.

    Science.gov (United States)

    Küçükkaya, Selen; Görduysus, Mehmet Ömer; Zeybek, Naciye Dilara; Müftüoğlu, Sevda Fatma

    2016-01-01

    The aim of this study was to evaluate the cytotoxicity of three types of calcium silicate-based endodontic cement after different incubation periods with human periodontal ligament fibroblasts. Human periodontal ligament fibroblasts were cultured from extracted third molars and seeded in 96-well plates. MTA, calcium enriched mixture (CEM) cement, and Biodentine were prepared and added to culture insert plates which were immediately placed into 96-well plates containing cultured cells. After incubation periods of 24, 48, and 72 hours, cell viability was determined with WST-1 assay. Data were analysed statistically by ANOVA with repeated measures and Bonferroni tests. There was no significant difference in cell viability amongst the test materials after each incubation period (P > 0.05). MTA and CEM presented more than 90% cell viability after 24 and 48 hours of incubation and showed statistically significant decrease in cell viability after 72 hours of incubation (P Biodentine showed significantly less cell viability (73%) after 24 hours of incubation, whereas more than 90% cell viability was seen after 48 and 72 hours of incubation (P Biodentine and CEM can be considered as alternative materials for root-end surgery procedures. PMID:26904364

  9. Orthotic devices using lightweight composite materials

    Science.gov (United States)

    Harrison, E., Jr.

    1983-01-01

    Potential applications of high strength, lightweight composite technology in the orthotic field were studied. Several devices were designed and fabricated using graphite-epoxy composite technology. Devices included shoe plates, assistive walker devices, and a Simes prosthesis reinforcement. Several other projects having medical application were investigated and evaluations were made of the potential for use of composite technology. A seat assembly was fabricated using sandwich construction techniques for the Total Wheelchair Project.

  10. Composite materials: Fatigue and fracture. Vol. 3

    Science.gov (United States)

    O'Brien, T. K. (Editor)

    1991-01-01

    The present volume discusses topics in the fields of matrix cracking and delamination, interlaminar fracture toughness, delamination analysis, strength and impact characteristics, and fatigue and fracture behavior. Attention is given to cooling rate effects in carbon-reinforced PEEK, the effect of porosity on flange-web corner strength, mode II delamination in toughened composites, the combined effect of matrix cracking and free edge delamination, and a 3D stress analysis of plain weave composites. Also discussed are the compression behavior of composites, damage-based notched-strength modeling, fatigue failure processes in aligned carbon-epoxy laminates, and the thermomechanical fatigue of a quasi-isotropic metal-matrix composite.

  11. Some functional properties of composite material based on scrap tires

    Science.gov (United States)

    Plesuma, Renate; Malers, Laimonis

    2013-09-01

    The utilization of scrap tires still obtains a remarkable importance from the aspect of unloading the environment from non-degradable waste [1]. One of the most prospective ways for scrap tires reuse is a production of composite materials [2] This research must be considered as a continuation of previous investigations [3, 4]. It is devoted to the clarification of some functional properties, which are considered important for the view of practical applications, of the composite material. Some functional properties of the material were investigated, for instance, the compressive stress at different extent of deformation of sample (till 67% of initial thickness) (LVS EN 826) [5] and the resistance to UV radiation (modified method based on LVS EN 14836) [6]. Experiments were realized on the purposefully selected samples. The results were evaluated in the correlation with potential changes of Shore C hardness (Shore scale, ISO 7619-1, ISO 868) [7, 8]. The results showed noticeable resistance of the composite material against the mechanical influence and ultraviolet (UV) radiation. The correlation with the composition of the material, activity of binder, definite technological parameters, and the conditions supported during the production, were determined. It was estimated that selected properties and characteristics of the material are strongly dependent from the composition and technological parameters used in production of the composite material, and from the size of rubber crumb. Obtained results show possibility to attain desirable changes in the composite material properties by changing both the composition and technological parameters of examined material.

  12. Multi-Material Design Optimization of Composite Structures

    OpenAIRE

    Hvejsel, Christian Frier

    2011-01-01

    This PhD thesis entitled “Multi-Material Design Optimization of Composite Structures” addresses the design problem of choosing materials in an optimal manner under a resource constraint so as to maximize the integral stiffness of a structure under static loading conditions. In particular stiffness design of laminated composite structures is studied including the problem of orienting orthotropic material optimally. The approach taken in this work is to consider this multi-material design probl...

  13. Manufacturing and experimental investigation of green composite materials

    OpenAIRE

    Κουτσομητοπούλου, Αναστασία

    2013-01-01

    The aim of the present thesis is to explore sustainable low cost environmentally friendly composite materials. It is a step by step experimental research. Firstly, taking under consideration the so far commercial available non-organic materials used as reinforcement and the petroleum based resins used as matrices, composite materials were fabricated and mechanically characterized. Different components in micro- and nano- scale were combined. Afterwards, the non-organic materials used a...

  14. Characterization of nickel-doped biphasic calcium phosphate/graphene nanoplatelet composites for biomedical application.

    Science.gov (United States)

    Baradaran, S; Moghaddam, E; Nasiri-Tabrizi, Bahman; Basirun, W J; Mehrali, M; Sookhakian, M; Hamdi, M; Alias, Y

    2015-04-01

    The effect of the addition of an ionic dopant to calcium phosphates for biomedical applications requires specific research due to the essential roles played in such processes. In the present study, the mechanical and biological properties of Ni-doped hydroxyapatite (HA) and Ni-doped HA mixed with graphene nanoplatelets (GNPs) were evaluated. Ni (3wt.% and 6wt.%)-doped HA was synthesized using a continuous precipitation method and calcined at 900°C for 1h. The GNP (0.5-2wt.%)-reinforced 6% Ni-doped HA (Ni6) composite was prepared using rotary ball milling for 15h. The sintering process was performed using hot isostatic pressing at processing conditions of 1150°C and 160MPa with a 1-h holding time. The results indicated that the phase compositions and structural features of the products were noticeably affected by the Ni and GNPs. The mechanical properties of Ni6 and 1.5Ni6 were increased by 55% and 75% in hardness, 59% and 163% in fracture toughness and 120% and 85% in elastic modulus compared with monolithic HA, respectively. The in-vitro biological behavior was investigated using h-FOB osteoblast cells in 1, 3 and 5days of culture. Based on the osteoblast results, the cytotoxicity of the products was indeed affected by the Ni doping. In addition, the effect of GNPs on the growth and proliferation of osteoblast cells was investigated in Ni6 composites containing different ratios of GNPs, where 1.5wt.% was the optimum value. PMID:25686995

  15. Current perspectives of bio-ceramic technology in endodontics: calcium enriched mixture cement - review of its composition, properties and applications

    OpenAIRE

    Utneja, Shivani; Nawal, Ruchika Roongta; Talwar, Sangeeta; Verma, Mahesh

    2014-01-01

    Advancements in bio-ceramic technology has revolutionised endodontic material science by enhancing the treatment outcome for patients. This class of dental materials conciliates excellent biocompatibility with high osseoconductivity that render them ideal for endodontic care. Few recently introduced bio-ceramic materials have shown considerable clinical success over their early generations in terms of good handling characteristics. Calcium enriched mixture (CEM) cement, Endosequence sealer, a...

  16. Microhardness of resin composite materials light-cured through fiber reinforced composite.

    NARCIS (Netherlands)

    Fennis, W.M.M.; Ray, N.J.; Creugers, N.H.J.; Kreulen, C.M.

    2009-01-01

    OBJECTIVES: To compare polymerization efficiency of resin composite basing materials when light-cured through resin composite and fiber reinforced composite (FRC) by testing microhardness. METHODS: Simulated indirect restorations were prepared by application of resin composite (Clearfil AP-X) or FRC

  17. Improved Damage Resistant Composite Materials Incorporating Shape Memory Alloys

    Science.gov (United States)

    Paine, Jeffrey S. N.; Rogers, Craig A.

    1996-01-01

    Metallic shape memory alloys (SMA) such as nitinol have unique shape recovery behavior and mechanical properties associated with a material phase change that have been used in a variety of sensing and actuation applications. Recent studies have shown that integrating nitinol-SMA actuators into composite materials increases the composite material's functionality. Hybrid composites of conventional graphite/epoxy or glass/epoxy and nitinol-SMA elements can perform functions in applications where monolithic composites perform inadequately. One such application is the use of hybrid composites to function both in load bearing and armor capacities. While monolithic composites with high strength-to-weight ratios function efficiently as loadbearing structures, because of their brittle nature, impact loading can cause significant catastrophic damage. Initial composite failure modes such as delamination and matrix cracking dissipate some impact energy, but when stress exceeds the composite's ultimate strength, fiber fracture and material perforation become dominant. One of the few methods that has been developed to reduce material perforation is hybridizing polymer matrix composites with tough kevlar or high modulus polyethynylene plies. The tough fibers increase the impact resistance and the stiffer and stronger graphite fibers carry the majority of the load. Similarly, by adding nitinol-SMA elements that absorb impact energy through the stress-induced martensitic phase transformation, the composites' impact perforation resistance can be greatly enhanced. The results of drop-weight and high velocity gas-gun impact testing of various composite materials will be presented. The results demonstrate that hybridizing composites with nitinol-SMA elements significantly increases perforation resistance compared to other traditional toughening elements. Inspection of the composite specimens at various stages of perforation by optical microscope illustrates the mechanisms by which

  18. Worldwide flight and ground-based exposure of composite materials

    Science.gov (United States)

    Dexter, H. B.; Baker, D. J.

    1984-01-01

    The long-term durability of those advanced composite materials which are applicable to aircraft structures was discussed. The composite components of various military and commercial aircraft and helicopters were reviewed. Both ground exposure and flight service were assessed in terms of their impact upon composite structure durability. The ACEE Program is mentioned briefly.

  19. Flexible hydrogel-based functional composite materials

    Science.gov (United States)

    Song, Jie; Saiz, Eduardo; Bertozzi, Carolyn R; Tomasia, Antoni P

    2013-10-08

    A composite having a flexible hydrogel polymer formed by mixing an organic phase with an inorganic composition, the organic phase selected from the group consisting of a hydrogel monomer, a crosslinker, a radical initiator, and/or a solvent. A polymerization mixture is formed and polymerized into a desired shape and size.

  20. Structural assessment of a novel carpet composite material

    Science.gov (United States)

    Abbaszadeh, Ali

    Noise pollution caused by vehicles has always been a concern to the communities in the vicinity of highways and busy roadways. The carpet composite material was recently developed and proposed to be utilized as sound-walls in highways. In the carpet composite material post-consumer carpet is used as reinforcing element inside and epoxy matrix. The main focus of this work is to assess flexural behavior of this novel material. Tests were performed on the individual components of the composite material. Using the results from the test and a theoretical approach, a model was proposed that describes the flexural behavior and also a close estimate of the flexural strength of the carpet composite material. In this work the contribution of the carpet in flexural behavior of the composite material was investigated. It was found that the carpet is weaker than the epoxy and the contribution of the carpet in flexural strength of the composite material is small. It was also found that using the carpet inside the epoxy results in 63% decrease in ultimate strength of the section, however; the gain in ductility is considerable. Based on the flexural test results the composite section follows a bilinear behavior. To determine the capacity of the composite, the effective epoxy section is to be determined before and after the tension cracks form at the bottom of the section. Using the epoxy section analysis described in this work, the strength of the composite section can be calculated at cracking and ultimate capacity.

  1. Anticorrosive effects and in vitro cytocompatibility of calcium silicate/zinc-doped hydroxyapatite composite coatings on titanium

    Science.gov (United States)

    Huang, Yong; Zhang, Honglei; Qiao, Haixia; Nian, Xiaofeng; Zhang, Xuejiao; Wang, Wendong; Zhang, Xiaoyun; Chang, Xiaotong; Han, Shuguang; Pang, Xiaofeng

    2015-12-01

    This work elucidated the corrosion resistance and cytocompatibility of electroplated Zn- and Si-containing bioactive calcium silicate/zinc-doped hydroxyapatite (ZnHA/CS) ceramic coatings on commercially pure titanium (CP-Ti). The formation of ZnHA/CS coating was investigated through Fourier transform infrared spectroscopy, X-ray diffraction (XRD), scanning electron microscopy, energy dispersive X-ray and inductively coupled plasma analyses. The XRD image showed that the reaction layer was mainly composed of HA and CaSiO3. The fabricated ZnHA/CS coatings presented a porous structure and appropriate thickness for possible applications in orthopaedic surgery. Potentiodynamic polarization tests showed that ZnHA/CS coatings exhibited higher corrosion resistance than CP-Ti. Dissolution tests on the coating also revealed that Si4+ and Zn2+ were leached at low levels. Moreover, MC3T3-E1 cells cultured on ZnHA/CS featured improved cell morphology, adhesion, spreading, proliferation and expression of alkaline phosphatase than those cultured on HA. The high cytocompatibility of ZnHA/CS could be mainly attributed to the combination of micro-porous surface effects and ion release (Zn2+ and Si4+). All these results indicate that ZnHA/CS composite-coated CP-Ti may be a potential material for orthopaedic applications.

  2. The Cyogenic Evaluation of Irradiated Composite Materials for Use in Composite Pressure Vessels Project

    Data.gov (United States)

    National Aeronautics and Space Administration — HyPerComp Engineering, Inc. (HEI) proposes to continue the characterization of the cryogenic evaluation of irradiated composite materials for use in composite...

  3. New eco-friendly hybrid composite materials for civil construction

    OpenAIRE

    Eires, R.; Nunes, J. P.; Fangueiro, Raúl; Jalali, Said; Camões, Aires

    2006-01-01

    This paper concerns the development of new hybrid composite materials using granulated cork, a by-product of cork industry, cellulose pulp, from recycling of paper residues, and hemp fibres. The binder used is either cellulose pulp or lime-pozzolan mixture. Such materials may be used as composite boards and mortars for non structural elements of construction, such as dry walls and ceiling or floor levelling and filling. The possibility of using these composites in conjugation with light st...

  4. Characterization and Mechanical Behavior of Composite Material Using FEA

    OpenAIRE

    S. Irfan Sadaq; J. Dhanraj Pamar; Dr.N Seetharamaih; Afroz Mehar

    2013-01-01

    Composites have been used extensively in applications such as pipes and pressure vessels. Therefore there is need for furtherstudies on the physical and mechanical properties of these materials. In the present work composite laminates made of gl;ass fiber and epoxy resin are tested to find the strength of the laminate and also its mechanical properties. By using FEA (Ansys 11.0) the optimum helix angle is determined for the composite material

  5. Characterization and Mechanical Behavior of Composite Material Using FEA

    Directory of Open Access Journals (Sweden)

    S. Irfan Sadaq

    2013-04-01

    Full Text Available Composites have been used extensively in applications such as pipes and pressure vessels. Therefore there is need for furtherstudies on the physical and mechanical properties of these materials. In the present work composite laminates made of gl;ass fiber and epoxy resin are tested to find the strength of the laminate and also its mechanical properties. By using FEA (Ansys 11.0 the optimum helix angle is determined for the composite material

  6. Fabrication, characterization and biomedical application of two-nozzle electrospun polycaprolactone/zein-calcium lactate composite nonwoven mat.

    Science.gov (United States)

    Liao, Nina; Joshi, Mahesh Kumar; Tiwari, Arjun Prasad; Park, Chan-Hee; Kim, Cheol Sang

    2016-07-01

    The objective of the current work is to incorporate calcium lactate (CL) into polycaprolactone (PCL)/zein composite micro/nanofibrous scaffolds via electrospinning to engineer bone tissue. In this study, a composite micro/nano fibrous scaffold was fabricated using a single two-nozzle electrospinning system to combine indicative nanofibers from a blended solution of zein-CL and micro-sized fibers from a PCL solution. Incorporation of the CL into the PCL/zein fibers were shown to improve the wettability, tensile strength and biological activity of the composite mats. Moreover, the composite mats have a high efficiency to nucleate calcium phosphate from simulated body fluid (SBF) solution. An in vitro cell culture with osteoblast cells demonstrated that the electrospun composite mats possessed improved biological properties, including a better cell adhesion, spread and proliferation. This study has demonstrated that the PCL/zein-CL composite provides a simple platform to fabricate a new biomimetic scaffold for bone tissue engineering, which can recapitulate both the morphology of extracellular matrix and composition of the bone. PMID:26919567

  7. Fiber-reinforced composites materials, manufacturing, and design

    CERN Document Server

    Mallick, P K

    2007-01-01

    The newly expanded and revised edition of Fiber-Reinforced Composites: Materials, Manufacturing, and Design presents the most up-to-date resource available on state-of-the-art composite materials. This book is unique in that it not only offers a current analysis of mechanics and properties, but also examines the latest advances in test methods, applications, manufacturing processes, and design aspects involving composites. This third edition presents thorough coverage of newly developed materials including nanocomposites. It also adds more emphasis on underlying theories, practical methods, and problem-solving skills employed in real-world applications of composite materials. Each chapter contains new examples drawn from diverse applications and additional problems to reinforce the practical relevance of key concepts. New in The Third Edition: Contains new sections on material substitution, cost analysis, nano- and natural fibers, fiber architecture, and carbon-carbon composites Provides a new chapter on poly...

  8. Tension mechanical properties of recycled glass-epoxy composite material

    Directory of Open Access Journals (Sweden)

    Petrović Jelena M.

    2012-01-01

    Full Text Available The significance of composite materials and their applications are mainly due to their good properties. This imposes the need for their recycling, thus extending their lifetime. Once used composite material will be disposed as a waste at the end of it service life. After recycling, this kind of waste can be used as raw materials for the production of same material, which raises their applicability. This indicates a great importance of recycling as a method of the renowal of composite materials. This study represents a contribution to the field of mechanical properties of the recycled composite materials. The tension mechanical properties (tensile strength and modulus of elasticity of once used and disposed glass-epoxy composite material were compared before and after the recycling. The obtained results from mechanical tests confirmed that the applied recycling method was suitable for glass-epoxy composite materials. In respect to the tensile strength and modulus of elasticity it can be further assessed the possibility of use of recycled glass-epoxy composite materials.

  9. Nano composite phase change materials microcapsules

    Science.gov (United States)

    Song, Qingwen

    MicroPCMs with nano composite structures (NC-MicroPCMs) have been systematically studied. NC-MicroPCMs were fabricated by the in situ polymerization and addition of silver NPs into core-shell structures. A full factorial experiment was designed, including three factors of core/shell, molar ratio of formaldehyde/melamine and NPs addition. 12 MicroPCMs samples were prepared. The encapsulated efficiency is approximately 80% to 90%. The structural/morphological features of the NC-MicroPCMs were evaluated. The size was in a range of 3.4 mu m to 4.0 mu m. The coarse appearance is attributed to NPs and NPs are distributed on the surface, within the shell and core. The NC-MicroPCMs contain new chemical components and molecular groups, due to the formation of chemical bonds after the pretreatment of NPs. Extra X-ray diffraction peaks of silver were found indicating silver nano-particles were formed into an integral structure with the core/shell structure by means of chemical bonds and physical linkages. Extra functionalities were found, including: (1) enhancement of IR radiation properties; (2) depression of super-cooling, and (3) increase of thermal stabilities. The effects of SERS (Surface Enhanced Raman Spectroscopy) arising from the silver nano-particles were observed. The Raman scattering intensity was magnified more than 100 times. These effects were also exhibited in macroscopic level in the fabric coatings as enhanced IR radiation properties were detected by the "Fabric Infrared Radiation Management Tester" (FRMT). "Degree of Crystallinity" (DOC) was measured and found the three factors have a strong influence on it. DOC is closely related to thermal stability and MicroPCMs with a higher DOC show better temperature resistance. The thermal regulating effects of the MicroPCMs coatings were studied. A "plateau regions" was detected around the temperature of phase change, showing the function of PCMs. Addition of silver nano-particles to the MicroPCMs has a positive

  10. Development and characterization of 430L matrix composites gradient materials

    Directory of Open Access Journals (Sweden)

    Elisa Maria Ruiz-Navas

    2005-03-01

    Full Text Available This paper deals with a new concept that is Functionally Gradient Materials (FGM. The materials developed in this work are constituted by a 430L matrix core and composite materials with this matrix and gradient concentration with NbC reinforcement, from the core to the surface, through different steps. Composite powders of different content in NbC were produced through high energy milling in order to obtain the gradient composition. The morphology and microhardness of these powders were characterised and subsequently were processed through conventional P/M techniques, pressing and sintering. The materials obtained show improved wear behaviour.

  11. Nondestructive evaluation of composite materials - A design philosophy

    Science.gov (United States)

    Duke, J. C., Jr.; Henneke, E. G., II; Stinchcomb, W. W.; Reifsnider, K. L.

    1984-01-01

    Efficient and reliable structural design utilizing fiber reinforced composite materials may only be accomplished if the materials used may be nondestructively evaluated. There are two major reasons for this requirement: (1) composite materials are formed at the time the structure is fabricated and (2) at practical strain levels damage, changes in the condition of the material, that influence the structure's mechanical performance is present. The fundamental basis of such a nondestructive evaluation capability is presented. A discussion of means of assessing nondestructively the material condition as well as a damage mechanics theory that interprets the material condition in terms of its influence on the mechanical response, stiffness, strength and life is provided.

  12. A Material Model for FE-Simulation of UD Composites

    Science.gov (United States)

    Fischer, Sebastian

    2016-04-01

    Composite materials are being increasingly used for industrial applications. CFRP is particularly suitable for lightweight construction due to its high specific stiffness and strength properties. Simulation methods are needed during the development process in order to reduce the effort for prototypes and testing. This is particularly important for CFRP, as the material is costly. For accurate simulations, a realistic material model is needed. In this paper, a material model for the simulation of UD-composites including non-linear material behaviour and damage is developed and implemented in Abaqus. The material model is validated by comparison with test results on a range of test specimens.

  13. The influence of temperature on the fluorine and calcium composition of fish scales.

    Science.gov (United States)

    Gauldie, R W; Coote, G; West, I F; Radtke, R L

    1990-01-01

    Proton microprobe studies of the scales of the kahawai (Arripis trutta) and the snapper (Chrysophrys auratus) showed non-linear changes in the fluorine to calcium ratio that increase with increasing temperature, but both species showed a different temperature sensitivity. Fluorine and calcium levels vary within years from summer to winter by up to 1000%, making fluorine and calcium levels good markers of seasonal events. PMID:18620324

  14. Radiation Processing of Advanced Composite Materials

    International Nuclear Information System (INIS)

    Advanced composites, such as carbon-fiber-reinforced plastics, are being used widely for many applications. Carbon fiber/epoxies composites have attracted special attention from the aircraft, aerospace, marine engineering, sporting goods and transportation industries, because they have useful mechanical properties including high strength-to-weight and stiffness-to-weight ratios, a corrosion resistant, impact and damage tolerance characteristics and wear properties. Thermal curing has been the dominant industrial process for advanced composites until now, however, a radiation curing process using UV, microwave x-ray, electron-beam(E-beam) and γ-ray has emerged as a better alternative in recent years. These processes are compatible with the manufacturing of composites using traditional fabrication methods including a filament/tape winding, pultrusion, resin transfer moulding and hand lay-up. In this study, E-beam curable carbon fiber/epoxy composites were manufactured, and their mechanical properties were investigated. Two epoxy resins (bisphenol-A, bisphenol-F) containing photo-initiators (tri aryl sulfonium hexafluorophosphate, tri aryl sulfonium hexafluoroantimonate) were used as a matrix and a 4H-satin carbon woven fabric was used as a reinforcement. And then an electron beam irradiated the composites up to 200 kGy in a vacuum and an inert atmosphere. The cure cycle was optimized and the properties of composites were evaluated and analyzed via a differential scanning calorimetry, scanning electron microscopy, sol-gel extractions, FT-NIR, universal test machine, and an impact tester. The gel content, glass transition temperature and mechanical strength of the irradiated composites were increased with an increasing radiation dose

  15. Thermal treatment and utilization of Al-rich waste in high calcium fly ash geopolymeric materials

    Science.gov (United States)

    Chindaprasirt, Prinya; Rattanasak, Ubolluk; Vongvoradit, Pimdao; Jenjirapanya, Supichart

    2012-09-01

    The Al-rich waste with aluminium and hydrocarbon as the major contaminant is generated at the wastewater treatment unit of a polymer processing plant. In this research, the heat treatment of this Al-rich waste and its use to adjust the silica/alumina ratio of the high calcium fly ash geopolymer were studied. To recycle the raw Al-rich waste, the waste was dried at 110°C and calcined at 400 to 1000°C. Mineralogical analyses were conducted using X-ray diffraction (XRD) to study the phase change. The increase in calcination temperature to 600, 800, and 1000°C resulted in the phase transformation. The more active alumina phase of active γ-Al2O3 was obtained with the increase in calcination temperature. The calcined Al-rich waste was then used as an additive to the fly ash geopolymer by mixing with high calcium fly ash, water glass, 10 M sodium hydroxide (NaOH), and sand. Test results indicated that the calcined Al-rich waste could be used as an aluminium source to adjust the silica/alumina ratio and the strength of geopolymeric materials. The fly ash geopolymer mortar with 2.5wt% of the Al-rich waste calcined at 1000°C possessed the 7-d compressive strength of 34.2 MPa.

  16. Ammonia Decomposition with Manganese Nitride-Calcium Imide Composites as Efficient Catalysts.

    Science.gov (United States)

    Yu, Pei; Guo, Jianping; Liu, Lin; Wang, Peikun; Wu, Guotao; Chang, Fei; Chen, Ping

    2016-02-19

    Ammonia has high gravimetric and volumetric hydrogen densities and is, therefore, considered a promising carrier for the production of COx -free molecular H2 for forthcoming energy systems. Alkaline earth metals are generally regarded as structural promoters of catalysts and employed in numerous catalytic processes. Here, we report that calcium imide (CaNH) has a strong synergistic effect on Mn6 N5 in catalyzing the decomposition of NH3 , leading to a ca. 40 % drop in apparent activation energy. At 773 K, the H2 formation rate over a Mn6 N5 -11CaNH composite catalyst is about an order of magnitude higher than that of Mn6 N5 and comparable to the highly active Ni/SBA-15 and Ru/Al2 O3 catalysts. Analysis by means of temperature-programmed decomposition (TPD), X-ray diffraction (XRD), and X-ray absorption near edge spectroscopy (XANES) reveal that CaNH participates in the catalysis via forming a [Ca6 MnN5 ]-like intermediate, thus altering the reaction pathway and energetics. A two-step catalytic cycle, accounting for the synergy between CaNH and Mn6 N5 , is proposed. PMID:26914173

  17. Band Structure Characteristics of Nacreous Composite Materials with Various Defects

    Science.gov (United States)

    Yin, J.; Zhang, S.; Zhang, H. W.; Chen, B. S.

    2016-06-01

    Nacreous composite materials have excellent mechanical properties, such as high strength, high toughness, and wide phononic band gap. In order to research band structure characteristics of nacreous composite materials with various defects, supercell models with the Brick-and-Mortar microstructure are considered. An efficient multi-level substructure algorithm is employed to discuss the band structure. Furthermore, two common systems with point and line defects and varied material parameters are discussed. In addition, band structures concerning straight and deflected crack defects are calculated by changing the shear modulus of the mortar. Finally, the sensitivity of band structures to the random material distribution is presented by considering different volume ratios of the brick. The results reveal that the first band gap of a nacreous composite material is insensitive to defects under certain conditions. It will be of great value to the design and synthesis of new nacreous composite materials for better dynamic properties.

  18. Early age corrosion of aluminium in calcium sulfo-aluminate cement based composites

    International Nuclear Information System (INIS)

    At present, encapsulation of low level and intermediate level nuclear wastes using Portland Cement (PC) based matrices is a preferred approach. However, it is now widely accepted that the high pH of the pore solution of these PC-based matrices (usually above pH 12.5) can cause concerns over the stability of certain wastes containing reactive metals, such as aluminium and uranium. One potential low pH system for reducing the corrosion of aluminium is calcium sulfo-aluminate cement (CSA). However, significant heat could be generated from the hydration of CSA, causing another concern to the nuclear industry. In the current study, various additives, namely pulverized fuel ash (PFA), ground granulated blast furnace slag (GGBS) and limestone powder (LSP) were used to replace part of the CSA in order to reduce the heat output. The results indicated that the replacement of CSA with GGBS, PFA and LSP can reduce the heat output of 100% CSA, although it is still higher than the control GGBS/PC 9:1 system. The corrosion rate of aluminium in each of the CSA composites was slightly higher than 100% CSA, however, all the CSA systems had corrosion rates lower than GGBS/PC 9:1 after 15 hours. Therefore, the composite CSA systems investigated in this study provide a good compromise between the heat output and the resistance to the corrosion of aluminium. Hence, offers a good potential for dealing with some historical nuclear wastes where the corrosion of aluminium is a concern. (authors)

  19. Multilayer composite material and method for evaporative cooling

    Science.gov (United States)

    Buckley, Theresa M. (Inventor)

    2002-01-01

    A multilayer composite material and method for evaporative cooling of a person employs an evaporative cooling liquid that changes phase from a liquid to a gaseous state to absorb thermal energy. The evaporative cooling liquid is absorbed into a superabsorbent material enclosed within the multilayer composite material. The multilayer composite material has a high percentage of the evaporative cooling liquid in the matrix. The cooling effect can be sustained for an extended period of time because of the high percentage of phase change liquid that can be absorbed into the superabsorbent. Such a composite can be used for cooling febrile patients by evaporative cooling as the evaporative cooling liquid in the matrix changes from a liquid to a gaseous state to absorb thermal energy. The composite can be made with a perforated barrier material around the outside to regulate the evaporation rate of the phase change liquid. Alternatively, the composite can be made with an imperveous barrier material or semipermeable membrane on one side to prevent the liquid from contacting the person's skin. The evaporative cooling liquid in the matrix can be recharged by soaking the material in the liquid. The multilayer composite material can be fashioned into blankets, garments and other articles.

  20. Composite Materials for Thermal Energy Storage: Enhancing Performance through Microstructures

    OpenAIRE

    Ge, Zhiwei; YE, Feng; Ding, Yulong

    2014-01-01

    Chemical incompatibility and low thermal conductivity issues of molten-salt-based thermal energy storage materials can be addressed by using microstructured composites. Using a eutectic mixture of lithium and sodium carbonates as molten salt, magnesium oxide as supporting material, and graphite as thermal conductivity enhancer, the microstructural development, chemical compatibility, thermal stability, thermal conductivity, and thermal energy storage performance of composite materials are inv...

  1. Manufacturing of Aluminum Composite Material Using Stir Casting Process

    OpenAIRE

    Jokhio, Muhammad Hayat; Panhwer, Muhammad Ibrahim; Unar, Mukhtiar Ali

    2016-01-01

    Manufacturing of aluminum alloy based casting composite materials via stir casting is one of the prominent and economical route for development and processing of metal matrix composites materials. Properties of these materials depend upon many processing parameters and selection of matrix and reinforcements. Literature reveals that most of the researchers are using 2, 6 and 7xxx aluminum matrix reinforced with SiC particles for high strength properties whereas, insufficient information is ava...

  2. Manufacturing of Aluminum Composite Material Using Stir Casting Process

    OpenAIRE

    Muhammad Hayat Jokhio; Muhammad Ibrahim Panhwar; Mukhtiar Ali Unar

    2011-01-01

    Manufacturing of aluminum alloy based casting composite materials via stir casting is one of the prominent and economical route for development and processing of metal matrix composites materials. Properties of these materials depend upon many processing parameters and selection of matrix and reinforcements. Literature reveals that most of the researchers are using 2, 6 and 7xxx aluminum matrix reinforced with SiC particles for high strength properties whereas, insufficient inf...

  3. THE COMPARISON OF SEVERAL STANDARD MATERIALS AND TECHNIQUES FOR THE WARREN-AVERBACH DETERMINATION OF MICRO-STRUCTURE CHARACTERISTICS OF CALCIUM HYDROXIDE SORBENT MATERIALS

    Science.gov (United States)

    The paper gives results of a comparison of several standard materials and techniques for the Warren-Averbach determination of microstructure characteristics of calcium hydroxide--Ca(OH)2--sorbent materials. The comparison is part of an investigation of the injection of dry Ca(OH)...

  4. Standard Guide for Testing Polymer Matrix Composite Materials

    CERN Document Server

    American Society for Testing and Materials. Philadelphia

    2011-01-01

    1.1 This guide summarizes the application of ASTM standard test methods (and other supporting standards) to continuous-fiber reinforced polymer matrix composite materials. The most commonly used or most applicable ASTM standards are included, emphasizing use of standards of Committee D30 on Composite Materials. 1.2 This guide does not cover all possible standards that could apply to polymer matrix composites and restricts discussion to the documented scope. Commonly used but non-standard industry extensions of test method scopes, such as application of static test methods to fatigue testing, are not discussed. A more complete summary of general composite testing standards, including non-ASTM test methods, is included in the Composite Materials Handbook (MIL-HDBK-17). Additional specific recommendations for testing textile (fabric, braided) composites are contained in Guide D6856. 1.3 This guide does not specify a system of measurement; the systems specified within each of the referenced standards shall appl...

  5. Effects of calcium phosphate/chitosan composite on bone healing in rats: calcium phosphate induces osteon formation.

    Science.gov (United States)

    Fernández, Tulio; Olave, Gilberto; Valencia, Carlos H; Arce, Sandra; Quinn, Julian M W; Thouas, George A; Chen, Qi-Zhi

    2014-07-01

    Vascularization of an artificial graft represents one of the most significant challenges facing the field of bone tissue engineering. Over the past decade, strategies to vascularize artificial scaffolds have been intensively evaluated using osteoinductive calcium phosphate (CaP) biomaterials in animal models. In this work, we observed that CaP-based biomaterials implanted into rat calvarial defects showed remarkably accelerated formation and mineralization of new woven bone in defects in the initial stages, at a rate of ∼60 μm/day (0.8 mg/day), which was considerably higher than normal bone growth rates (several μm/day, 0.1 mg/day) in implant-free controls of the same age. Surprisingly, we also observed histological evidence of primary osteon formation, indicated by blood vessels in early-region fibrous tissue, which was encapsulated by lamellar osteocyte structures. These were later fully replaced by compact bone, indicating complete regeneration of calvarial bone. Thus, the CaP biomaterial used here is not only osteoinductive, but vasculogenic, and it may have contributed to the bone regeneration, despite an absence of osteons in normal rat calvaria. Further investigation will involve how this strategy can regulate formation of vascularized cortical bone such as by control of degradation rate, and use of models of long, dense bones, to more closely approximate repair of human cortical bone. PMID:24460696

  6. Technology obtaining of nitrogen fertilizer from the calcium is containing waste of production of calcium saltpetre

    OpenAIRE

    Власян, Світлана Варужанівна; Шестозуб, Анатолій Борисович; Волошин, Микола Дмитрович

    2013-01-01

    The new technology of obtaining nitrogen fertilizer from calcium-containing sludge of calcium saltpeter production is considered in the paper. The main objective of the research is the development of processing technology of sludge of calcium saltpeter production into alkaline nitrogen fertilizer, analysis of the composition of initial material and finished product, testing of fertilizer by means of vegeta­tive studies and determination of expenditure of drying agent that is exhaust gases of ...

  7. The synthesis of spherical calcium carbonate composite in amphiphilic PS-b-PAA solution and its thermal dynamic characteristic

    Institute of Scientific and Technical Information of China (English)

    YUE Linhai; JIN Dalai

    2004-01-01

    Spherical calcium carbonate composite is synthesized in the solution of amphiphilic block copolymer of polystyrene(PS) and poly(acrylic acid)(PAA). SEM and XRD measurements show that the diameter of the particulates decreases with the augment of the PS-b-PAA concentration, crystalline in the composite is calcite and its morphology as well as the structure is changed too. TG-DTA together with IR analysis is applied to investigating the thermal dynamic behavior of the composite. The results show that the composite is mainly composed of two phases, that is, the nano- crystalline calcium carbonate and the PS-b-PA-Ca composites. PS phase decomposes first with a large heat release at about 330℃. However, the PAA chains have relatively high thermal stability, probably due to the structural Ca-O bond, and decomposes at above 400℃. Matching opinions are used to explain the possible reasons for the regular as well as the particular characteristics of the composite corresponding to a certain copolymer concentration.

  8. Bond strength of a calcium silicate-based sealer tested in bulk or with different main core materials

    OpenAIRE

    Nagas, Emre; Cehreli, Zafer; Mehmet Ozgur UYANIK; Veli DURMAZ

    2014-01-01

    The aim of this study was to evaluate the influence of a calcium silicate-based sealer (iRoot SP), with or without a core material, on bond strength to radicular dentin, in comparison with various contemporary root filling systems. Root canals of freshly extracted single-rooted teeth (n = 60) were instrumented using rotary instruments. The roots were randomly assigned to one of the following experimental groups: (1) a calcium silicate-based sealer without a core material (bulk-fill); (2) a ca...

  9. Growth and characterization of triglycine calcium dibromide, a semiorganic NLO material

    International Nuclear Information System (INIS)

    Single crystals of semiorganic material triglycine calcium dibromide (TGCB) were grown from aqueous solution. The solubility and metastable zone width were found. Single crystal X-ray diffraction analysis was used to estimate the cell parameters of the grown crystals. The structural perfection of crystals has been analyzed by high-resolution X-ray diffraction (HRXRD) rocking curve measurements. Energy dispersive X-ray analysis confirms the presence of elements in the title compound. The grown crystals were tested by FTIR, thermogravimetric and differential thermal analysis, UV-vis-NIR analysis, and dielectrical and mechanical studies. The transmittance of TGCB crystal has been used to calculate the refractive index n, the extinction coefficient K and both the real εr and imaginary εi components of the dielectric constant as functions of wavelength. The second harmonic conversion efficiency of TGCB was determined using the Kurtz and Perry powder technique; it was observed to be greater than that of KDP.

  10. Spin crossover composite materials for electrothermomechanical actuators

    OpenAIRE

    Gural'Skiy, Il'Ya A.; Quintero, Carlos M; Costa, José Sánchez; Demont, Philippe; Molnar, Gabor; Salmon, Lionel; Shepherd, Helena J.; Bousseksou, Azzedine

    2014-01-01

    Composites of the spin crossover complex [Fe(trz)(H-trz)2](BF4) (H-trz ¼ 1,2,4-4H-triazole and trz ¼ 1,2,4-triazolato) dispersed in a poly(methylmethacrylate) (PMMA) matrix were synthesized and investigated for their spin crossover properties by optical reflectivity, Raman spectroscopy and calorimetry. These composite films were used to fabricate bilayer cantilevers that can perform efficient and tuneable mechanical actuation based on the spin transition. A prototype device that uses the spin...

  11. Thermal management of electronic components with thermal adaptation composite material

    International Nuclear Information System (INIS)

    Thermal adaptation composite material is a kind of composite material with required thermal conductivity or coefficient of thermal expansion through the selection and design of its components. A kind of thermal adaptation composite material that has excellent thermal conductivity and heat storage capacity is prepared by absorbing paraffin into expanded graphite. An electronic cooling experimental system based on the thermal adaptation composite material is built. The temperature variations of the simulative chip are respectively measured in this system and the traditional cooling system to investigate the effect of the thermal adaptation composite material on electronic cooling. At the same time, the impacts of composite material dosage and combining active cooling manner on the performance of electronic cooling are also studied. The experimental results show that the apparent heat transfer coefficients of the electronic cooling experimental system are 1.25-1.30 times higher than those of the traditional cooling system. It also can be found that the dosage of composite material has positive impact on the performance of electronic cooling. By combining active cooling manner, it can compensate the deficiency of cooling capacity in phase change thermal control.

  12. Flexible composite material with phase change thermal storage

    Science.gov (United States)

    Buckley, Theresa M. (Inventor)

    2001-01-01

    A highly flexible composite material having a flexible matrix containing a phase change thermal storage material. The composite material can be made to heat or cool the body or to act as a thermal buffer to protect the wearer from changing environmental conditions. The composite may also include an external thermal insulation layer and/or an internal thermal control layer to regulate the rate of heat exchange between the composite and the skin of the wearer. Other embodiments of the PCM composite also provide 1) a path for evaporation or direct absorption of perspiration from the skin of the wearer for improved comfort and thermal control, 2) heat conductive pathways within the material for thermal equalization, 3) surface treatments for improved absorption or rejection of heat by the material, and 4) means for quickly regenerating the thermal storage capacity for reuse of the material. Applications of the composite materials are also described which take advantage of the composite's thermal characteristics. The examples described include a diver's wet suit, ski boot liners, thermal socks, ,gloves and a face mask for cold weather activities, and a metabolic heating or cooling blanket useful for treating hypothermia or fever patients in a medical setting and therapeutic heating or cooling orthopedic joint supports.

  13. Interfacial Design of Composite Ablative Materials Project

    Data.gov (United States)

    National Aeronautics and Space Administration — This Small Business Innovation Research (SBIR) project proposes the development of a computational software package to provide NASA with advanced materials...

  14. Stiffness analysis of the sarafix external fixator of composite materials

    Directory of Open Access Journals (Sweden)

    Nedim Pervan

    2016-01-01

    Full Text Available This paper describes a structural analysis of the CAD model three versions fixators Sarafix which to explore the possibility of introducing composite materials in the construction of the connecting rod fixators comparing values of displacement and stiffness at characteristic points structure. Namely, we investigated constructional performance of fixators Sarafix with a connecting rod formed from three different composite materials, the same matrix (epoxy resin with three different types of fibers (E glass, kevlar 49 and carbon M55J. Results of structural analysis fixators Sarafix with a connecting rod made of composite materials are compared with the results of tubular connecting rod fixators made of stainless steel. After comparing the results, from the aspect of stiffness, we gave the final considerations about composite material which provides an adequate substitution for the existing material.

  15. LIGNOCELLULOSIC-PLASTIC COMPOSITES FROM RECYCLED MATERIALS

    Science.gov (United States)

    Waste wood, waste paper, and waste plastics are major components of MSW and offer great opportunities as recycled ingredients in wood-fiber plastic composites. USEPA and the USDA Forest Products Laboratory (FPL) are collaborating on a research project to investigate the processin...

  16. Structured Piezoelectric Composites: Materials and Applications

    NARCIS (Netherlands)

    Van den Ende, D.A.

    2012-01-01

    The piezoelectric effect, which causes a material to generate a voltage when it deforms, is very suitable for making integrated sensors, and (micro-) generators. However, conventional piezoelectric materials are either brittle ceramics or certain polymers with a low thermal stability, which limits t

  17. A constitutive model for creep and damage in composite materials

    International Nuclear Information System (INIS)

    The concepts underlying slip theories of polycrystalline materials are implemented for the determination of constitutive equation for composite materials. The creep deformation and an influence of damages are described on the local planes. The area length density of cracks serves as an indicator for the extent of deterioration of the material and may be estimated by the use of stereological methods. (orig.)

  18. Influence of composite material's structure on its durability

    International Nuclear Information System (INIS)

    This article is devoted to influence of composite material's structure on its durability. The influence of volume content and the number of thermo cycles on durability of expanded-clay concrete was carried out. It was shown that volume content of needle fibre in expanded-clay concrete increased proportional to composite material's durability increase. But at the same time thermo cycles decreased the durability. Therefore, combining the needle fibre content and the number of thermo cycles it is possible to manage durability and viscosity of composite materials.

  19. Effect of uncoated calcium carbonate and stearic acid coated calcium carbonate on mechanical, thermal and structural properties of poly(butylene terephthalate) (PBT)/calcium carbonate composites

    Indian Academy of Sciences (India)

    G S Deshmukh; S U Pathak; D R Peshwe; J D Ekhe

    2010-06-01

    PBT/CaCO3 composites were prepared in a single screw extruder with particle content varying from 0–30% by weight. The influence of surface treatment of the particles, with and without stearic acid (SA), on the mechanical, thermal and structural properties was studied. The experiments included tensile tests, impact tests, differential scanning calorimetry (DSC), scanning electron microscopy (SEM), X-ray diffraction (XRD) and Fourier transform infrared spectroscopy. The composite systems containing SA coated CaCO3 were found to exhibit better mechanical properties as compared to composite systems containing uncoated CaCO3, with the S3 system (20% of SA coated CaCO3) exhibiting best combination of mechanical properties. Thermal study revealed that particle type and content had no influence on the melting temperature but the crystallization temperature, % crystallinity and thermal stability increased on increasing the CaCO3 content in PBT matrix. Morphological observation indicated that in PBT composites containing SA coated CaCO3, the coupling agent favours a better polymer filler interaction rendering inorganic polymer interface compatible, which is also evident from better mechanical and thermal properties.

  20. Electrochemical and morphological investigation of silver and zinc modified calcium phosphate bioceramic coatings on metallic implant materials.

    Science.gov (United States)

    Furko, M; Jiang, Y; Wilkins, T A; Balázsi, C

    2016-05-01

    In our research nanostructured silver and zinc doped calcium-phosphate (CaP) bioceramic coatings were prepared on commonly used orthopaedic implant materials (Ti6Al4V). The deposition process was carried out by the pulse current technique at 70°C from electrolyte containing the appropriate amount of Ca(NO3)2 and NH4H2PO4 components. During the electrochemical deposition Ag(+) and Zn(2+) ions were introduced into the solution. The electrochemical behaviour and corrosion rate of the bioceramic coatings were investigated by potentiodynamic polarization and Electrochemical Impedance Spectroscopy (EIS) measurements in conventional Ringer's solution in a three electrode open cell. The coating came into contact with the electrolyte and corrosion occurred during immersion. In order to achieve antimicrobial properties, it is important to maintain a continuous release of silver ions into physiological media, while the bioactive CaP layer enhances the biocompatibility properties of the layer by fostering the bone cell growth. The role of Zn(2+) is to shorten wound healing time. Morphology and composition of coatings were studied by Scanning Electron Microscopy, Transmission Electron Microscopy and Energy-dispersive X-ray spectroscopy. Differential thermal analyses (DTA) were performed to determine the thermal stability of the pure and modified CaP bioceramic coatings while the structure and phases of the layers were characterized by X-ray diffraction (XRD) measurements. PMID:26952421

  1. Solubility of a new calcium silicate-based root-end filling material

    Directory of Open Access Journals (Sweden)

    Shishir Singh

    2015-01-01

    Full Text Available Introduction: The purpose of this study was to compare solubility of a new calcium silicate-based cement, Biodentine with three commonly used root-end filling materials viz. glass-ionomer cement (GIC, intermediate restorative material (IRM, and mineral trioxide aggregate (MTA. Materials and Methods: Twenty stainless steel ring molds were filled with cements corresponding to four groups (n = 5. The weight of 20 dried glass bottles was recorded. Samples were transferred to bottles containing 5 ml of distilled water and stored for 24 h. The bottles were dried at 105΀C and weighed. This procedure was repeated for 3, 10, 30, and 60 days. Data was analyzed with one-way analysis of variance (ANOVA test (P < 0.05. Results: Biodentine demonstrated significantly higher solubility than MTA for 30- and 60-day immersion periods. Statistical difference was noted between the solubility values of Biodentine samples amongst each of the five time intervals. Conclusions: Biodentine exhibited higher solubility in comparison with all other cements.

  2. Factors affecting energy absorption capability of polymer composite materials

    International Nuclear Information System (INIS)

    A study was conducted to investigate the effects of through thickness properties on the crush behaviour of composites structures produced from various composite materials. A comprehensive experimental evaluation of plate specimens was conducted to develop insight into how composite plate elements crush and what are the controlling mechanism. In this study mechanisms that control the crushing process were defined and the crushing modes of composite plates, buckling effect, lamina bending and transverse shearing were also identified. An overall understanding of effect of material properties on energy absorption capability of composite materials was examined. The relative effect of fibre orientation on energy-absorption capability was evaluated. Interlaminar shear strength (ILSS). values were recorded from short beam shear tests and used as a measure of through thickness strength for each materials construction tested. The ILSS values were then plotted against the specific sustained crushing stress (SSCS) values obtained for each material using a plate crushing test. A significant link between the interlaminar shear strength (ILSS) and specific sustained crushing stress (SSCS) was recorded for laminates which appear independent of fibre alignment in the laminate. The indications are that the key routes to improving the energy absorbing properties of fibre based composites is to raise the interlaminar and through thickness strengths of the materials. An analysis to predict the energy absorption capability of composite plate specimens was developed. Good agreement between experiment and prediction was obtained. Observations on the crushed specimens were carried out on Scanning Electron Microscope (SEM) to identify fibre/matrix behaviour during crushing. (author)

  3. Porous calcium phosphate-poly (lactic-co-glycolic) acid composite bone cement: A viable tunable drug delivery system.

    Science.gov (United States)

    Roy, Abhijit; Jhunjhunwala, Siddharth; Bayer, Emily; Fedorchak, Morgan; Little, Steve R; Kumta, Prashant N

    2016-02-01

    Calcium phosphate based cements (CPCs) are frequently used as bone void fillers for non-load bearing segmental bone defects due to their clinically relevant handling characteristics and ability to promote natural bone growth. Macroporous CPC scaffolds with interconnected pores are preferred for their ability to degrade faster and enable accelerated bone regeneration. Herein, a composite CPC scaffold is developed using newly developed resorbable calcium phosphate cement (ReCaPP) formulation containing degradable microspheres of bio-compatible poly (lactic-co-glycolic acid) (PLGA) serving as porogen. The present study is aimed at characterizing the effect of in-vitro degradation of PLGA microspheres on the physical, chemical and structural characteristics of the composite cements. The porosity measurements results reveal the formation of highly interconnected macroporous scaffolds after degradation of PLGA microspheres. The in-vitro characterizations also suggest that the degradation by products of PLGA reduces the pH of the local environment thereby increasing the dissolution rate of the cement. In addition, the in-vitro vancomycin release from the composite CPC scaffold suggests that the drug association with the composite scaffolds can be tuned to achieve control release kinetics. Further, the study demonstrates control release lasting for longer than 10weeks from the composite cements in which vancomycin is encapsulated in PLGA microspheres. PMID:26652353

  4. Comparing the reinforcing effects of a resin modified glassionomer cement, Flowable compomer, and Flowable composite in the restoration of calcium hydroxide-treated immature roots in vitro

    Directory of Open Access Journals (Sweden)

    S Prathibha Rani

    2011-01-01

    Full Text Available One hundred and sixty human permanent central incisors were enlarged to a 120 file size after crown removal procedure to simulate immature teeth. The root canals were filled with calcium hydroxide and stored for 15 days (phase I, 30 days (phase II, 90 days (phase III, and 180 days (Phase IV. At the end of these selected time periods, calcium hydroxide was cleaned off the root canals of forty teeth that were randomly selected and obturated with gutta-percha points in the apical 2 mm of the root canals with a sealer. The specimens were further equally divided into four groups. Unrestored Group I served as control and the root canals of teeth in the other three group specimens were reinforced with resin modified glassionomer cement (RMGIC (Group II, Flowable Compomer (Group III, and Flowable Composite (Group IV, respectively, using a translucent curing post. All specimens were subjected to compressive force using an Instron Testing machine, until fracture occurred. All the materials evaluated substantially reinforced the root specimens compared to the control. At the end of 180 days, Flowable composites showed maximum reinforcement compared to the other groups; however, no significant differences were found between the reinforcement capabilities of Flowable Compomer and RMGIC.

  5. Strontium-doped calcium polyphosphate/ultrahigh molecular weight polyethylene composites: A new class of artificial joint components with enhanced biological efficacy to aseptic loosening.

    Science.gov (United States)

    Gu, Zhipeng; Huang, Bingxue; Li, Yiwen; Tian, Meng; Li, Li; Yu, Xixun

    2016-04-01

    To enhance implant stability and prolong the service life of artificial joint component, a new approach was proposed to improve the wear resistance of artificial joint component and endow artificial joint component with the biological efficacy of resistance to aseptic loosening. Strontium calcium polyphosphate (SCPP) were interfused in ultrahigh molecular weight polyethylene (UHMWPE) by a combination of liquid nitrogen ball-milling and flat-panel curing process to prepare the SCPP/UHMWPE composites. The micro-structure, mechanical characterization, tribological characterization and bioactivities of various SCPP/UHMWPE composites were investigated. The results suggested that this method could statistically improve the wear resistance of UHMWPE resulting from a good SCPP particle dispersion. Moreover, it is also observed that the SCPP/UHMWPE composites-wear particles could promote the production of OPG by osteoblasts and decrease the production of RANKL by osteoblasts, and then increase the OPG/RANKL ratio. This indicated that the SCPP/UHMWPE composites had potential efficacy to prevent and treat aseptic loosening. Above all, the SCPP/UHMWPE composites with a suitable SCPP content would be the promising materials for fabricating artificial joint component with ability to resist aseptic loosening. PMID:26838880

  6. Mechanical behaviour of composite materials made by resin film infusion

    Directory of Open Access Journals (Sweden)

    Casavola C.

    2010-06-01

    Full Text Available Innovative composite materials are frequently used in designing aerospace, naval and automotive components. In the typical structure of composites, multiple layers are stacked together with a particular sequence in order to give specific mechanical properties. Layers are organized with different angles, different sequences and different technological process to obtain a new and innovative material. From the standpoint of engineering designer it is useful to consider the single layer of composite as macroscopically homogeneous material. However, composites are non homogeneous bodies. Moreover, layers are not often perfectly bonded together and delamination often occurs. Other violations of lamination theory hypotheses, such as plane stress and thin material, are not unusual and in many cases the transverse shear flexibility and the thickness-normal stiffness should be considered. Therefore the real behaviour of composite materials is quite different from the predictions coming from the traditional lamination theory. Due to the increasing structural performance required to innovative composites, the knowledge of the mechanical properties for different loading cases is a fundamental source of concern. Experimental characterization of materials and structures in different environmental conditions is extremely important to understand the mechanical behaviour of these new materials. The purpose of the present work is to characterize a composite material developed for aerospace applications and produced by means of the resin film infusion process (RFI. Different tests have been carried out: tensile, open-hole and filled-hole tensile, compressive, openhole and filled-hole compressive. The experimental campaign has the aim to define mechanical characteristics of this RFI composite material in different conditions: environmental temperature, Hot/Wet and Cold.

  7. Interfacial models in viscoplastic composites materials

    OpenAIRE

    Monchiet, Vincent; Bonnet, Guy

    2010-01-01

    The aim of the present work is to extend the concept of interphase and equivalent imperfect interface in the context of viscoplasticity. The interphase takes the form of a thin curved layer of constant thickness, made up of a rigid viscoplastic material located between two other surrounding materials. We aim at representing this interphase by an interface with appropriately devised interface conditions. To reach this objective, a Taylor expansion of the relevant physical fields in the thin re...

  8. Status and Perspectives of Multiferroic Magnetoelectric Composite Materials and Applications

    Directory of Open Access Journals (Sweden)

    Haribabu Palneedi

    2016-03-01

    Full Text Available Multiferroic magnetoelectric (ME composites are attractive materials for various electrically and magnetically cross-coupled devices. Many studies have been conducted on fundamental understanding, fabrication processes, and applications of ME composite material systems in the last four decades which has brought the technology closer to realization in practical devices. In this article, we present a review of ME composite materials and some notable potential applications based upon their properties. A brief summary is presented on the parameters that influence the performance of ME composites, their coupling structures, fabrications processes, characterization techniques, and perspectives on direct (magnetic to electric and converse (electric to magnetic ME devices. Overall, the research on ME composite systems has brought us closer to their deployment.

  9. Electrical Characterizations of Lightning Strike Protection Techniques for Composite Materials

    Science.gov (United States)

    Szatkowski, George N.; Nguyen, Truong X.; Koppen, Sandra V.; Ely, Jay J.; Mielnik, John J.

    2009-01-01

    The growing application of composite materials in commercial aircraft manufacturing has significantly increased the risk of aircraft damage from lightning strikes. Composite aircraft designs require new mitigation strategies and engineering practices to maintain the same level of safety and protection as achieved by conductive aluminum skinned aircraft. Researchers working under the NASA Aviation Safety Program s Integrated Vehicle Health Management (IVHM) Project are investigating lightning damage on composite materials to support the development of new mitigation, diagnosis & prognosis techniques to overcome the increased challenges associated with lightning protection on composite aircraft. This paper provides an overview of the electrical characterizations being performed to support IVHM lightning damage diagnosis research on composite materials at the NASA Langley Research Center.

  10. The behaviour of fibrous composite materials under nuclear radiations exposure

    International Nuclear Information System (INIS)

    The main feature of fibrous composite materials are briefly described, which are constitued by a netwoek of ceramic high performance fiber embebed in a ductile matrix material. These composite materials show such a kind of anisotropic strength that their uses has been widely spreaded in the last times. This philosophy of strengthening was used by the Nature, where are abundant examples of fibrous composites like horn, bamboo tissues, etc. In this paper are collected the published results about behaviour of reinforced dibers and fibrous composites under nuclear radiation exposure. The results show a very wide sort of fenomenae depending on many factors. Are fibers, like the boron one, which shows an inconvenient behaviour and another like graphite fibers which appears to improve its features. Is is concluded that was not achieved enough information about the behaviour of the interface under irradiation in order to build up a theory about the behaviour of the full composite under irradiation exposure. (author)

  11. Evaluation of radiation-shielding properties of the composite material

    International Nuclear Information System (INIS)

    The paper presents the evaluation of radiation-shielding properties of composite materials with respect to gamma-radiation. As a binder for the synthesis of radiation-shielding composites we used lead boronsilicate glass matrix. As filler we used nanotubular chrysotile filled with lead tungstate PbWO4. It is shown that all the developed composites have good physical-mechanical characteristics, such as compressive strength, thermal stability and can be used as structural materials. On the basis of theoretical calculation we described the graphs of the gamma-quanta linear attenuation coefficient depending on the emitted energy for all investigated composites. We founded high radiation-shielding properties of all the composites on the basis of theoretical and experimental data compared to materials conventionally used in the nuclear industry - iron, concrete, etc

  12. Using Virtual Testing for Characterization of Composite Materials

    Science.gov (United States)

    Harrington, Joseph

    Composite materials are finally providing uses hitherto reserved for metals in structural systems applications -- airframes and engine containment systems, wraps for repair and rehabilitation, and ballistic/blast mitigation systems. They have high strength-to-weight ratios, are durable and resistant to environmental effects, have high impact strength, and can be manufactured in a variety of shapes. Generalized constitutive models are being developed to accurately model composite systems so they can be used in implicit and explicit finite element analysis. These models require extensive characterization of the composite material as input. The particular constitutive model of interest for this research is a three-dimensional orthotropic elasto-plastic composite material model that requires a total of 12 experimental stress-strain curves, yield stresses, and Young's Modulus and Poisson's ratio in the material directions as input. Sometimes it is not possible to carry out reliable experimental tests needed to characterize the composite material. One solution is using virtual testing to fill the gaps in available experimental data. A Virtual Testing Software System (VTSS) has been developed to address the need for a less restrictive method to characterize a three-dimensional orthotropic composite material. The system takes in the material properties of the constituents and completes all 12 of the necessary characterization tests using finite element (FE) models. Verification and validation test cases demonstrate the capabilities of the VTSS.

  13. Calcium Phosphate Mineralization in Cellulose Derivative/Poly(acrylic acid) Composites Having a Chiral Nematic Mesomorphic Structure.

    Science.gov (United States)

    Ogiwara, Takuya; Katsumura, Ayaka; Sugimura, Kazuki; Teramoto, Yoshikuni; Nishio, Yoshiyuki

    2015-12-14

    Calcium phosphate mineralization was conducted by using polymer composites of liquid-crystalline (ethyl)cellulose (EC) or (hydroxypropyl)cellulose (HPC) with poly(acrylic acid) (PAA) as a scaffolding medium for the inorganic deposition. The EC/PAA and HPC/PAA samples were prepared in colored film form from EC and HPC lyotropic liquid crystals of left-handed and right-handed chiral nematics, respectively, by polymerization and cross-linking of acrylic acid as the main solvent component. The mineralization was allowed to proceed in a batchwise operation by soaking the liquid-crystalline films in an aqueous salt solution containing the relevant ions, Ca(2+) and HPO4(2-). The calcium phosphate-deposited EC/PAA and HPC/PAA composites (weight gain, typically 15-25% and 6-11%, respectively) retained the chiral nematic organization of the respective original handedness but exhibited selective light-reflection of longer wavelengths relative to that of the corresponding nonmineralized samples. From X-ray diffraction and energy-dispersive X-ray spectroscopy measurements, it was deduced that the calcium and phosphorus were incorporated inside the polymer matrices in three forms: amorphous calcium phosphate, hydroxyapatite, and a certain complex of PAA-Ca(2+). Dynamic mechanical analysis and thermogravimetry revealed that the inorganic hybridization remarkably enhanced the thermal and mechanical performance of the optically functionalized cellulosic/synthetic polymer composites; however, the effect was more drastic in the EC/PAA series rather than the HPC/PAA series, reflecting the difference in the deposited mineral amount between the two. PMID:26536381

  14. Calcium isotopic composition of high-latitude proxy carrier Neogloboquadrina pachyderma (sin.

    Directory of Open Access Journals (Sweden)

    A. Eisenhauer

    2009-01-01

    Full Text Available The accurate reconstruction of sea surface temperature (SST history in climate-sensitive regions (e.g. tropical and polar oceans became a challenging task in palaeoceanographic research. Biogenic shell carbonate SST proxies successfully developed for tropical regions often fail in cool water environments. Their major regional shortcomings and the cryptic diversity now found within the major high latitude proxy carrier Neogloboquadrina pachyderma (sin. highlight an urgent need to explore complementary SST proxies for these cool-water regions. Here we incorporate the genetic component into a calibration study of a new SST proxy for the high latitudes. We found that the calcium isotopic composition (δ44/40Ca of calcite from genotyped net catches and core-top samples of the planktonic foraminifera Neogloboquadrina pachyderma (sin. is related to temperature and unaffected by genetic variations. The temperature sensitivity has been found to be 0.17 (±0.02‰ per 1°C, highlighting its potential for downcore applications in open marine cool-water environments. Our results further indicate that in extreme polar environments, below a critical threshold temperature of 2.0 (±0.5°C associated with salinities below 33.0 (±0.5‰, a prominent shift in biomineralization affects the δ44/40Ca of genotyped and core-top N. pachyderma (sin., becoming insensitive to temperature. These findings highlight the need of more systematic calibration studies on single planktonic foraminiferal species in order to unravel species-specific factors influencing the temperature sensitivity of Ca isotope fractionation and to validate the proxies' applicability.

  15. Calcium oxalate nephrolithiasis: effect of renal crystal deposition on the cellular composition of the renal interstitium.

    Science.gov (United States)

    de Water, R; Noordermeer, C; van der Kwast, T H; Nizze, H; Boevé, E R; Kok, D J; Schröder, F H

    1999-04-01

    Urinary calcium oxalate (CaOx) crystals and crystal agglomerates are normally harmlessly excreted, but in nephrolithiasis they are retained by tubular epithelial cells and shifted into the renal interstitium. This crystalline material induces an inflammatory response consisting of an increase in the number of interstitial cells and an expansion of the extracellular matrix. The newly arrived cells either derive from the blood or the connective tissue or they are formed by local proliferation. Identification of the cells that surround the interstitial crystals is a first step in investigating the question of whether the interstitial cells could remove the crystalline material. Therefore, we performed an immunohistochemical study on the kidneys of rats made hyperoxaluric by ethylene glycol (EG) and ammonium chloride (AC). Attention was paid to expression of the leukocyte common antigen (LCA), which identifies all types of leukocytes, the ED1 antigen, which is specific for monocytes and macrophages, and the major histocompatibility class II antigen (MHC II), which is present on dendritic cells, B lymphocytes, and activated macrophages. The results obtained were compared with those seen in two human kidney specimens with acute and chronic oxalosis. In both rat and humans, macrophages and multinucleated giant cells are the major cells that encapsulate the interstitial crystals. This similarity in response underlines the relevance of the rat nephrolithiasis model. The rat experiments showed, furthermore, that the number of interstitial crystals and the amount of biochemically measured kidney-associated oxalate both decrease with time, if the nephrolithiatic agents EG and AC are omitted from the drinking water. Further studies must clarify whether macrophages and multinucleated giant cells are able to remove the interstitial crystals and how these cells are recruited at the inflammatory site. PMID:10196021

  16. Physical and mechanical properties of composite materials of different compositions based on waste products

    Directory of Open Access Journals (Sweden)

    A.E. Burdonov

    2012-12-01

    Full Text Available This paper presents a study on the effect of mineral filler on the polymer composite material based on waste products of heat and power engineering - fly ash. This type of waste products has never been used for the production of polymer-mineral composites. Depending on the type of ash, its chemical composition and its quantity in the material, we can adjust the properties of the resulting composites. The use of fly ash as a filler will not only make a product less expensive, but it also will reduce development pressure on the environment and improve the physical and mechanical properties of the material. The article shows research results of the ash chemical composition as well as the properties of the resulting materials on its basis. According to the research conclusions there is a prospect for using this material in the construction industry.

  17. Identification of effective properties of particle reinforced composite materials

    OpenAIRE

    Kushnevsky, V.; Morachkovsky, O.; Altenbach, H.

    1998-01-01

    For the determination of effective elastic properties an energy averaging procedure has been used for particle reinforced composite materials. This procedure is based on finite element calculations of the deformation energy of a characteristic volume element. The proposed approach allows the determination of effective properties of particle reinforced composite with acceptable precision. The calculated effective properties of the composite are found in range between upper and lower Hashin-Sht...

  18. Composite materials for thermal energy storage: enhancing performance through microstructures.

    Science.gov (United States)

    Ge, Zhiwei; Ye, Feng; Ding, Yulong

    2014-05-01

    Chemical incompatibility and low thermal conductivity issues of molten-salt-based thermal energy storage materials can be addressed by using microstructured composites. Using a eutectic mixture of lithium and sodium carbonates as molten salt, magnesium oxide as supporting material, and graphite as thermal conductivity enhancer, the microstructural development, chemical compatibility, thermal stability, thermal conductivity, and thermal energy storage performance of composite materials are investigated. The ceramic supporting material is essential for preventing salt leakage and hence provides a solution to the chemical incompatibility issue. The use of graphite gives a significant enhancement on the thermal conductivity of the composite. Analyses suggest that the experimentally observed microstructural development of the composite is associated with the wettability of the salt on the ceramic substrate and that on the thermal conduction enhancer. PMID:24591286

  19. Flight service environmental effects on composite materials and structures

    Science.gov (United States)

    Dexter, H. Benson; Baker, Donald J.

    1992-01-01

    NASA Langley and the U.S. Army have jointly sponsored programs to assess the effects of realistic flight environments and ground-based exposure on advanced composite materials and structures. Composite secondary structural components were initially installed on commercial transport aircraft in 1973; secondary and primary structural components were installed on commercial helicopters in 1979; and primary structural components were installed on commercial aircraft in the mid-to-late 1980's. Service performance, maintenance characteristics, and residual strength of numerous components are reported. In addition to data on flight components, 10 year ground exposure test results on material coupons are reported. Comparison between ground and flight environmental effects for several composite material systems are also presented. Test results indicate excellent in-service performance with the composite components during the 15 year period. Good correlation between ground-based material performance and operational structural performance has been achieved.

  20. Uncertainty on Fatigue Damage Accumulation for Composite Materials

    DEFF Research Database (Denmark)

    Toft, Henrik Stensgaard; Sørensen, John Dalsgaard

    2009-01-01

    In the present paper stochastic models for fatigue damage accumulation for composite materials are presented based on public available constant and variable amplitude fatigue tests. The methods used for estimating the SN-curve and accumulated fatigue damage are presented....

  1. Review of probabilistic models of the strength of composite materials

    International Nuclear Information System (INIS)

    The available literature concerning probabilistic models describing the strength of composite materials has been reviewed to highlight the important aspects of this behaviour which will be of interest to the modelling and analysis of a complex system. The success with which these theories have been used to predict experimental results has been discussed. Since the brittle reinforcement phase largely controls the strength of composites, the probabilistic theories used to describe the strength of brittle materials, fibres and bundles of fibres have been detailed. The use of these theories to predict the strength of composite materials has been considered, along with further developments incorporating the damage accumulation observed in the failure of such materials. Probabilistic theories of the strength of short-fibre composites have been outlined. Emphasis has been placed throughout on straightforward engineering explanations of these theories and how they may be used, rather than providing comprehensive statistical descriptions

  2. COMPOSITION BUILDING MATERIALS ON THE BASIS OF MODIFIED LIQUID OLIGODIENES

    OpenAIRE

    D. E. Barabash

    2010-01-01

    The results of elaboration of efficient building composites on the basis of modified oligodienes are presented. The basic propositions on design of ma-terial formulations for different purposes with consideration for the particu-larities of their use are given. The ways of improvement of technology of composites preparation subject to proposed operation conditions are sug-gested.

  3. Materials Research Society Proceedings: Interfaces in Composites, volume 170

    Science.gov (United States)

    Pantano, Carlo G.; Chen, Eric J. H.

    1990-11-01

    Reports on the following topics are presented: (1) micromechanics of interfaces; (2) characterization of interfaces; (3) interface reactions in ceramic and metal systems; (4) interface effects in ceramic and metal matrix composites; and (5) interface effects in polymer matrix composites. A list of the materials research society symposium proceedings is also presented.

  4. Uncertainty modelling and code calibration for composite materials

    DEFF Research Database (Denmark)

    Toft, Henrik Stensgaard; Branner, Kim; Mishnaevsky, Leon, Jr;

    2013-01-01

    between risk of failure and cost of the structure. Consideration related to calibration of partial safety factors for composite material is described, including the probability of failure, format for the partial safety factor method and weight factors for different load cases. In a numerical example, it......Uncertainties related to the material properties of a composite material can be determined from the micro-, meso- or macro-scales. These three starting points for a stochastic modelling of the material properties are investigated. The uncertainties are divided into physical, model, statistical and...

  5. An Expert System in FRP Composite Material Design

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    An expert system prototype for fibre-reinforced plastic matrix (FRP) composite material design,ESFRP, has been developed. The system consists of seven main functional parts: a general inference engine, a set of knowledge bases, a material properties algorithm base, an explanation engine, various data bases, several function models and the user interface. The ESFRP can simulate human experts to make design scheme for fibre-reinforced plastics design, FRP layered plates design and FRP typical engineering components design. It can also predict the material properties and make strength analysis according to the micro and macro mechanics of composite materials. A satisfied result can be gained through the reiterative design.

  6. Low-Cost Composite Materials and Structures for Aircraft Applications

    Science.gov (United States)

    Deo, Ravi B.; Starnes, James H., Jr.; Holzwarth, Richard C.

    2003-01-01

    A survey of current applications of composite materials and structures in military, transport and General Aviation aircraft is presented to assess the maturity of composites technology, and the payoffs realized. The results of the survey show that performance requirements and the potential to reduce life cycle costs for military aircraft and direct operating costs for transport aircraft are the main reasons for the selection of composite materials for current aircraft applications. Initial acquisition costs of composite airframe components are affected by high material costs and complex certification tests which appear to discourage the widespread use of composite materials for aircraft applications. Material suppliers have performed very well to date in developing resin matrix and fiber systems for improved mechanical, durability and damage tolerance performance. The next challenge for material suppliers is to reduce material costs and to develop materials that are suitable for simplified and inexpensive manufacturing processes. The focus of airframe manufacturers should be on the development of structural designs that reduce assembly costs by the use of large-scale integration of airframe components with unitized structures and manufacturing processes that minimize excessive manual labor.

  7. Size-controlled hydroxyapatite nanoparticles as self-organized organic-inorganic composite materials.

    Science.gov (United States)

    Rusu, Viorel Marin; Ng, Chuen-How; Wilke, Max; Tiersch, Brigitte; Fratzl, Peter; Peter, Martin G

    2005-09-01

    This paper presents some results concerning the size-controlled hydroxyapatite nanoparticles obtained in aqueous media in a biopolymer matrix from soluble precursors salts. Taking the inspiration from nature, where composite materials made of a polymer matrix and inorganic fillers are often found, e.g. bone, shell of crustaceans, shell of eggs, etc., the feasibility on making composite materials containing chitosan and nanosized hydroxyapatite was investigated. A stepwise co-precipitation approach was used to obtain different types of composites by means of different ratio between components. The synthesis of hydroxyapatite was carried out in the chitosan matrix from calcium chloride and sodium dihydrogenphosphate in alkaline solutions at moderate pH of 10-11 for 24 h. Our research is focused on studying and understanding the structure of this class of composites, aiming at the development of novel materials, controlled at the nanolevel scale. The X-ray diffraction technique was employed in order to study the kinetic of hydroxyapatite formation in the chitosan matrix as well as to determine the HAp crystallite sizes in the composite samples. The hydroxyapatite synthesized using this route was found to be nano-sized (15-50 nm). Moreover, applying an original approach to analyze the (002) XRD diffraction peak profile of hydroxyapatite by using a sum of two Gauss functions, the bimodal distribution of nanosized hydroxyapatite within the chitosan matrix was revealed. Two types of size distribution domains such as cluster-like (between 200 and 400 nm), which are the habitat of ''small'' hydroxyapatite nanocrystallites and scattered-like, which are the habitat of ''large'' hydroxyapatite nanocrystallites was probed by TEM and CSLM. The structural features of composites suggest that self-assembly processes might be involved. The composites contain nanosized hydroxyapatite with structural features close to those of biological apatites that make them attractive for bone

  8. Mechanical Characterization of Cotton Fiber/Polyester Composite Material

    Directory of Open Access Journals (Sweden)

    Altaf Hussain Rajper

    2014-04-01

    Full Text Available Development of composite from natural fiber for lower structural application is growing for long-term sustainable perspective. Cotton fiber composite material has the added advantages of high specific strength, corrosion resistance, low cost and low weight compared to glass fiber on the expense of internal components of IC engines. The primary aim of the research study is to examine the effect of the cotton fiber on mechanical properties of lower structural applications when added with the polyester resin. In this paper composite material sample has been prepared by hand Lay-Up process. A mould is locally developed in the laboratory for test sample preparation. Initially samples of polyester resin with appropriate ratio of the hardener were developed and tested. At the second stage yarns of cotton fiber were mixed with the polyester resin and sample specimens were developed and tested. Relative effect of the cotton as reinforcing agent was examined and observed that developed composite specimen possess significant improvement in mechanical properties such as tensile strength was improved as 19.78 % and modulus of elasticity was increased up to 24.81%. Through this research it was also observed that developed composite material was of ductile nature and its density decreases up to 2.6%. Results from this study were compared with relevant available advanced composite materials and found improved mechanical properties of developed composite material

  9. Ceramic matrix composites -- Advanced high-temperature structural materials

    International Nuclear Information System (INIS)

    This symposium on Ceramic Matrix Composites: Advanced High-Temperature Structural Materials was held at the 1994 MRS Fall Meeting in Boston, Massachusetts on November 28--December 2. The symposium was sponsored by the Department of Energy's Office of Industrial Technology's Continuous Fiber Ceramic Composites Program, the Air Force Office of Scientific Research, and NASA Lewis Research Center. Among the competing materials for advanced, high-temperature applications, ceramic matrix composites are leading candidates. The symposium was organized such that papers concerning constituents--fibers and matrices--were presented first, followed by composite processing, modeling of mechanical behavior, and thermomechanical testing. More stable reinforcements are necessary to enhance the performance and life of fiber-reinforced ceramic composites, and to ensure final acceptance of these materials for high-temperature applications. Encouraging results in the areas of polymer-derived SiC fibers and single crystal oxide filaments were given, suggesting composites with improved thermomechanical properties and stability will be realized in the near future. The significance of the fiber-matrix interface in the design and performance of these materials is evident. Numerous mechanical models to relate interface properties to composite behavior, and interpret test methods and data, were enthusiastically discussed. One issue of great concern for any advanced material for use in extreme environments is stability. This theme arose frequently throughout the symposium and was the topic of focus on the final day. Fifty nine papers have been processed separately for inclusion on the data base

  10. Mechanical characterization of cotton fiber/polyester composite material

    International Nuclear Information System (INIS)

    Development of composite from natural fiber for lower structural application is growing for long-term sustainable perspective. Cotton fiber composite material has the added advantages of high specific strength, corrosion resistance, low cost and low weight compared to glass fiber on the expense of internal components of IC engines. The primary aim of the research study is to examine the effect of the cotton fiber on mechanical properties of lower structural applications when added with the polyester resin. In this paper composite material sample has been prepared by hand Lay-Up process. A mould is locally developed in the laboratory for test sample preparation. Initially samples of polyester resin with appropriate ratio of the hardener were developed and tested. At the second stage yarns of cotton fiber were mixed with the polyester resin and sample specimens were developed and tested. Relative effect of the cotton as reinforcing agent was examined and observed that developed composite specimen possess significant improvement in mechanical properties such as tensile strength was improved as 19.78 % and modulus of elasticity was increased up to 24.81%. Through this research it was also observed that developed composite material was of ductile nature and its density decreases up to 2.6%. Results from this study were compared with relevant available advanced composite materials and found improved mechanical properties of developed composite material. (author)

  11. Problems and perspectives of application of composite materials in aircraft

    OpenAIRE

    Savchenko, V. A.

    2015-01-01

    Purpose. Aircraft uses a very wide range of constructional technologies, but the technological progress and economic crisis lead to the research of composite materials with high mechanical and operational properties level. The advantage of such materials is the low density, which reduces the overall weight and increase fuel economy and increases airplanes' passenger capacity. Methodology. The values of the exploitation characteristics (specific strength, specific stiffness) of composite mater...

  12. Uncertainty on Fatigue Damage Accumulation for Composite Materials

    OpenAIRE

    Toft, Henrik Stensgaard; Sørensen, John Dalsgaard

    2009-01-01

    In the present paper stochastic models for fatigue damage accumulation for composite materials are presented based on public available constant and variable amplitude fatigue tests. The methods used for estimating the SN-curve and accumulated fatigue damage are presented. In the present paper stochastic models for fatigue damage accumulation for composite materials are presented based on public available constant and variable amplitude fatigue tests. The methods used for estimating the SN-...

  13. Mechanical behaviour of composite materials made by resin film infusion

    OpenAIRE

    Casavola C.; Pappalettere C.; Barile C.; Tursi F.

    2010-01-01

    Innovative composite materials are frequently used in designing aerospace, naval and automotive components. In the typical structure of composites, multiple layers are stacked together with a particular sequence in order to give specific mechanical properties. Layers are organized with different angles, different sequences and different technological process to obtain a new and innovative material. From the standpoint of engineering designer it is useful to consider the single layer of ...

  14. Physical and Model Uncertainty for Fatigue Design of Composite Material

    DEFF Research Database (Denmark)

    Toft, Henrik Stensgaard; Sørensen, John Dalsgaard

    The main aim of the present report is to establish stochastic models for the uncertainties related to fatigue design of composite materials. The uncertainties considered are the physical uncertainty related to the static and fatigue strength and the model uncertainty related to Miners rule for...... linear damage accumulation. Test data analyzed are taken from the Optimat database [1] which is public available. The composite material tested within the Optimat project is normally used for wind turbine blades....

  15. Material optimization of fiber reinforced composites applying a damage formulation

    OpenAIRE

    Kato, Junji

    2010-01-01

    The present thesis proposes material optimization schemes for fiber reinforced composites, specifically for a new composite material, denoted as Fiber Reinforced Concrete (FRC) or Textile Reinforced Concrete (TRC); here a reinforcement mesh of long carbon or glass fibers is embedded in a fine grained concrete (mortar) matrix. Unlike conventional steel reinforcement, these textile fibers are corrosion free; this holds also for AR-glass due to its high alkali-proof. This favorable property allo...

  16. Development of graphite-polymer composites as electrode materials

    Directory of Open Access Journals (Sweden)

    Carolina Maria Fioramonti Calixto

    2007-06-01

    Full Text Available Graphite powder was mixed to polyurethane, silicon rubber and Araldite® (epoxy in order to prepare composite materials to be used in the preparation of electrodes. Results showed that voltammetric response could be obtained when at least 50% of graphite (w.w-1 is present in the material. SEM and thermogravimetry were also used in the characterization of the composites.

  17. Polymer composites filled with powders as polymer graded materials

    OpenAIRE

    J. Stabik; A. Dybowska; M. Chomiak

    2010-01-01

    Purpose: The goal of this paper is to present general overview of research results on Polymeric Gradient Materials (PGMs) performed in Division of Metallic and Polymeric Materials Processing of Silesian University of Technology. Achievements in research on production technologies, compositions and properties are presented.Design/methodology/approach: Two basic technologies that were used for preparing polymeric gradient composites filled with powders are presented (centrifugal and gravity cas...

  18. Percolation Modeling of Self-Damaging of Composite Materials

    OpenAIRE

    Domanskyi, Sergii; Privman, Vladimir

    2013-01-01

    We propose the concept of autonomous self-damaging in "smart" composite materials, controlled by activation of added nanosize "damaging" capsules. Percolation-type modeling approach earlier applied to the related concept of self-healing materials, is used to investigate the behavior of the initial material's fatigue. We aim at achieving a relatively sharp drop in the material's integrity after some initial limited fatigue develops in the course of the sample's usage. Our theoretical study con...

  19. Mechanical behaviour of dental composite filling materials using digital holography

    OpenAIRE

    Monteiro, J. M.; Lopes, H.; Vaz, M.A.P.; Campos, J.C. Reis

    2010-01-01

    One of the most common clinical problems in dentistry is tooth decay. Among the dental filling materials used to repair tooth structure that has been destroyed by decay are dental amalgam and composite materials based on acrylics. Dental amalgam has been used by dentists for the past 150 years as a dental restorative material due to its low cost, ease of application, strength, durability, and bacteriostatic effects. However its safety as a filling material has been questioned due to th...

  20. Phase stress measurements in composite materials

    Energy Technology Data Exchange (ETDEWEB)

    Akiniwa, Yoshiaki; Tanaka, Keisuke [Nagoya Univ. (Japan). School of Engineering

    1997-06-01

    Using an aluminum alloy composite containing 20 wt.% of SiC powder and an aluminum alloy itself, a phase stress under monoaxial tensile load was tested using x-ray and neutron methods, to compare both of them. For specimens, a 20 vol.% SiC powder reinforced aluminum alloy and an aluminum alloy itself were used. As a result, the following results could be obtained. Young`s modulus and Poisson ratio of the aluminum alloy itself using x-ray method were E=74.5 GPa and {nu}=0.312, respectively, and those using neutron method were E=75.3 GPa and {nu}=0.384, respectively. A relationship between loading stress and lattice strain of the aluminum alloy itself using neutron method was possible to approximate linearly by containing macroscopic plastic deformation region. The lattice strain of each phase in the composite increased proportionally with loading stress in its elastic region, but when remarkably increasing plastic deformation, the lattice strain decreased proportionally in aluminum phase and increased in SiC phase. (G.K.)

  1. Fast, Contactless Monitoring of the Chemical Composition of Raw Materials

    Science.gov (United States)

    Ivanov, O.; Stoyanov, Zh.; Stoyanov, B.; Nadoliisky, M.; Vaseashta, Ashok

    A technique to monitor chemical composition of materials during manufacturing of ceramic products, in particular - of bricks, is investigated. The technique of monitoring is likely to offset environmental pollution and save energy. For this purpose, we use the Surface photo charge effect, which is generated for each solid body interacting with electromagnetic field. The measurement is express and can be performed in-situ in production conditions. The experimental work has shown that different samples of the investigated materials with different compositions produce different signals specific to each sample. For the same material, the signal varies with the change in chemical composition. More specifically, it is shown that for the material from which the bricks are fired, the signal is a function of the percentage of coal sludge. The results indicate that the characterization technique as a viable technique for control of incoming raw materials.

  2. Carbon Cryogel Silicon Composite Anode Materials for Lithium Ion Batteries

    Science.gov (United States)

    Woodworth James; Baldwin, Richard; Bennett, William

    2010-01-01

    A variety of materials are under investigation for use as anode materials in lithium-ion batteries, of which, the most promising are those containing silicon. 10 One such material is a composite formed via the dispersion of silicon in a resorcinol-formaldehyde (RF) gel followed by pyrolysis. Two silicon-carbon composite materials, carbon microspheres and nanofoams produced from nano-phase silicon impregnated RF gel precursors have been synthesized and investigated. Carbon microspheres are produced by forming the silicon-containing RF gel into microspheres whereas carbon nano-foams are produced by impregnating carbon fiber paper with the silicon containing RF gel to create a free standing electrode. 1-4,9 Both materials have demonstrated their ability to function as anodes and utilize the silicon present in the material. Stable reversible capacities above 400 mAh/g for the bulk material and above 1000 mAh/g of Si have been observed.

  3. Lightweight Composite Materials for Heavy Duty Vehicles

    Energy Technology Data Exchange (ETDEWEB)

    Pruez, Jacky; Shoukry, Samir; Williams, Gergis; Shoukry, Mark

    2013-08-31

    The main objective of this project is to develop, analyze and validate data, methodologies and tools that support widespread applications of automotive lightweighting technologies. Two underlying principles are guiding the research efforts towards this objective: • Seamless integration between the lightweight materials selected for certain vehicle systems, cost-effective methods for their design and manufacturing, and practical means to enhance their durability while reducing their Life-Cycle-Costs (LCC). • Smooth migration of the experience and findings accumulated so far at WVU in the areas of designing with lightweight materials, innovative joining concepts and durability predictions, from applications to the area of weight savings for heavy vehicle systems and hydrogen storage tanks, to lightweighting applications of selected systems or assemblies in light–duty vehicles.

  4. Composition of waste materials and recyclables

    DEFF Research Database (Denmark)

    Götze, Ramona

    decisions in waste planning thus require a holistic and systematic assessment of environmental impacts of different waste management options. Such assessment requires reliable information on the physical and chemical waste properties to model the flows of waste materials and substances throughout the entire...... for future modelling and assessment of waste management systems. The analyzed fractions were selected based on material properties with relevance for potential recycling processes. The physico-chemical analysis revealed chemical differences between residual and source-segregated samples for several fractions......As the valorization of waste has become a main objective of modern waste management a variety of waste technologies were developed and the complexity of management systems increased. Maximizing environmental benefits in one part of the system may lead to burdens in another. Environmentally sound...

  5. Development and characterization of composite materials for production of composite risers by filament winding

    Energy Technology Data Exchange (ETDEWEB)

    Sobrinho, L.L.; Bastian, F.L. [Federal University of Rio de Janeiro, RJ (Brazil). Dept. of Metallurgical and Materials Engineering], e-mail: ledjane@metalmat.ufrj.br; Calado, V.M.A. [Federal University of Rio de Janeiro, RJ (Brazil). Escola de Quimica

    2008-07-01

    Industry has been challenged to provide riser systems which are more cost effective and which can fill the technology gaps with respect to water depth, riser diameter and high temperatures left open by flexible, steel catenary risers (SCRs) and hybrid risers. Composite materials present advantages over conventional steel risers because composite materials are lighter, more fatigue and corrosion resistant, better thermal insulators and can be designed for improving the structural and mechanical response. Besides, composite materials present some attractive attributes for the offshore service, such as: high specific strength and stiffness. This paper focuses on the development and characterization of a polymer matrix (epoxy) and of material composite (epoxy/fiber glass), which will be used in a development for composites risers by the filament winding process (wet winding). (author)

  6. Interfacial forces in nanocellulose based composite materials

    OpenAIRE

    Olszewska, Anna Maria

    2013-01-01

    In this work, fundamental interactions in nanocellulose systems and their utility in fabricating novel and advanced cellulose-based materials was studied. More specifically two major aims were investigated. The first concentrates on cationic NFC and its morphology, its fundamental behavior with relation to charge and solvent, and its interactions with other nanocellulose particles. In the second, the approach focuses on the interfacial interactionbetween NFC and polymers (polysaccharides) to ...

  7. Multilayer Electroactive Polymer Composite Material Comprising Carbon Nanotubes

    Science.gov (United States)

    Ounaies, Zoubeida (Inventor); Park, Cheol (Inventor); Harrison, Joycelyn S. (Inventor); Holloway, Nancy M. (Inventor); Draughon, Gregory K. (Inventor)

    2009-01-01

    An electroactive material comprises multiple layers of electroactive composite with each layer having unique dielectric, electrical and mechanical properties that define an electromechanical operation thereof when affected by an external stimulus. For example, each layer can be (i) a 2-phase composite made from a polymer with polarizable moieties and an effective amount of carbon nanotubes incorporated in the polymer for a predetermined electromechanical operation, or (ii) a 3-phase composite having the elements of the 2-phase composite and further including a third component of micro-sized to nano-sized particles of an electroactive ceramic incorporated in the polymer matrix.

  8. Dynamic Mechanical Behavior of a Novel Polymeric Composite Damping Material

    Institute of Scientific and Technical Information of China (English)

    Cheng ZHANG; Jiang Feng SHENG; Chun An MA

    2005-01-01

    The dynamic mechanical behavior of a novel polymeric composite damping material has been investigated in this article. The composite consists of chlorinated polyethylene (CPE),N,N-dicyclohexyl-2-benzothiazolylsufenamide (DZ), 4,4'-thio-bis(3-methyl-6-tert-buthylphenol)(BPSR) and vapor-grown carbon fiber (VGCF). It is found that either the position or the intensity of damping peak can be controlled by changing the composition of CPE/DZ/BPSR composite. Within a certain composition region, damping peak maximum depends on CPE/DZ ratio, whereas damping peak position is controlled by BPSR content. Moreover, the improvement of storage modulus can be achieved by incorporation of VGCF. These results may imply that a damping material possessing both good damping properties and high strength can be designed and obtained.

  9. Electrospun Nanofiber Coating of Fiber Materials: A Composite Toughening Approach

    Science.gov (United States)

    Kohlman, Lee W.; Roberts, Gary D.

    2012-01-01

    Textile-based composites could significantly benefit from local toughening using nanofiber coatings. Nanofibers, thermoplastic or otherwise, can be applied to the surface of the fiber tow bundle, achieving toughening of the fiber tow contact surfaces, resulting in tougher and more damage-resistant/tolerant composite structures. The same technique could also be applied to other technologies such as tape laying, fiber placement, or filament winding operations. Other modifications to the composite properties such as thermal and electrical conductivity could be made through selection of appropriate nanofiber material. Control of the needle electric potential, precursor solution, ambient temperature, ambient humidity, airflow, etc., are used to vary the diameter and nanofiber coating morphology as needed. This method produces a product with a toughening agent applied to the fiber tow or other continuous composite precursor material where it is needed (at interfaces and boundaries) without interfering with other composite processing characteristics.

  10. Standard Practice for Fiber Reinforcement Orientation Codes for Composite Materials

    CERN Document Server

    American Society for Testing and Materials. Philadelphia

    2011-01-01

    1.1 This practice establishes orientation codes for continuous-fiber-reinforced composite materials. Orientation codes are explicitly provided for two-dimensional laminates and braids. The laminate code may also be used for filament-wound materials. A method is included for presenting subscript information in computerized formats that do not permit subscript notation.

  11. Extended propagation model for interfacial crack in composite material structure

    Institute of Scientific and Technical Information of China (English)

    闫相桥; 冯希金

    2002-01-01

    An interfacial crack is a common damage in a composite material structure . An extended propaga-tion model has been established for an interfacial crack to study the dependence of crack growth on the relativesizes of energy release rates at left and right crack tips and the properties of interfacial material characterize thegrowth of interfacial crack better.

  12. Mineralized polymer composites as biogenic bone substitute material

    Science.gov (United States)

    Shah, Rushita; Saha, Nabanita; Kitano, Takeshi; Saha, Petr

    2015-05-01

    Mineralized polymer composites (MPC) are recognized as potential fillers of bone defects. Though bioceramics exhibits quite a good bone-bonding and vascularization, it is considered to be too stiff and brittle for using alone. Thus, the use of polymer scaffold instead of bioceramics has several advantages including combining the osteoconductivity and bone-bonding potential of the inorganic phase with the porosity and interconnectivity of the three-dimensional construction. Aiming the advantages of ceramic-polymer composite scaffolds, the calcium carbonate (CaCO3) based biomineralized scaffold was prepared, where the PVP-CMC hydrogel was used as an extracellular matrix. This paper is reported about the morphology, swelling trend (in physiological solution) and viscoelastic behavior of (90 min mineralized) MPC. The dry MPC are off-white, coarse in texture, comparatively less flexible than the original PVP-CMC based hydrogel film, and the deposition of granular structures on the surface of the hydrogel film confirms about the development of biomineralized scaffold/polymer composites. Irrespective of thickness, the dry MPC shows higher values of swelling ratio within 30 min, which varies between 200-250 approximately. The dynamic viscoelastic nature of freshly prepared MPC was investigated applying 1% and 10% strain. At higher strain the viscoelastic moduli (G' and G") show significant change, and the nature of MPC turns from elastic to viscous. Based on the observed basic properties, the MPC (calcite based polymer composites) can be recommended for the treatment of adyanamic bone disorder.

  13. In vivo studies on the nitrogen, chlorine, calcium and phosphorus composition of rats by neutron activation analysis

    International Nuclear Information System (INIS)

    The role of neutron activation analysis 'in vivo' to determine the elementary composition of the rat organism is demonstrated. In part one the possibilities offered by certain methods which establish the elementary composition of living organisms are analyzed, together with the contribution and scope of neutron activation analysis. In part two the technical details of the neutron activation of rats in vivo are determined and the problems raised by application of the method considered. This is followed by an application of neutron activation analysis to research on changes in the nitrogen, chlorine, calcium and phosphorus composition of rats during growth (from 30 to 440 days) and important biological events such as puberty in both sexes, reproduction and lactation. Finally a study of the fertility rate and the effects of repeated irradiations on Sprague-Dawley rats are described

  14. Emissivity Results on High Temperature Coatings for Refractory Composite Materials

    Science.gov (United States)

    Ohlhorst, Craig W.; Vaughn, Wallace L.; Daryabeigi, Kamran; Lewis, Ronald K.; Rodriguez, Alvaro C.; Milhoan, James D.; Koenig, John R.

    2007-01-01

    The directional emissivity of various refractory composite materials considered for application for reentry and hypersonic vehicles was investigated. The directional emissivity was measured at elevated temperatures of up to 3400 F using a directional spectral radiometric technique during arc-jet test runs. A laboratory-based relative total radiance method was also used to measure total normal emissivity of some of the refractory composite materials. The data from the two techniques are compared. The paper will also compare the historical database of Reinforced Carbon-Carbon emissivity measurements with emissivity values generated recently on the material using the two techniques described in the paper.

  15. DOE Automotive Composite Materials Research: Present and Future Efforts

    Energy Technology Data Exchange (ETDEWEB)

    Warren, C.D.

    1999-08-10

    One method of increasing automotive energy efficiency is through mass reduction of structural components by the incorporation of composite materials. Significant use of glass reinforced polymers as structural components could yield a 20--30% reduction in vehicle weight while the use of carbon fiber reinforced materials could yield a 40--60% reduction in mass. Specific areas of research for lightweighting automotive components are listed, along with research needs for each of these categories: (1) low mass metals; (2) polymer composites; and (3) ceramic materials.

  16. Composite refractory materials for horizontal concasting of iron and steel

    International Nuclear Information System (INIS)

    The interaction of oxide-graphite composite materials with iron and steel melts was determined and the investigation was carried out at 1480 and 1600 deg. C for iron and steel respectively. The chemical and physical techniques including optical and electron microscopy, were employed. ZrO/sub 2/-C composites showed no significant corrosion/erosion by the Fe-C and Fe-C-Si melts. There was a major corrosion of these refractories by steel. Zirconia shows good corrosion/erosion resistance to attack by liquid Fe-C, Fe-C-Si and steel melts while graphite improves the thermal properties of these composites by increasing thermal conductivity and thermal shock resistance. In application to continuous casting, ZrO/sub 2/-C composite performed best of these composite refractories. The interaction of ZrO2-C composites with Fe-C, Fe-C-Si, and steel is discussed. (author)

  17. On the composition and atomic arrangement of calcium-deficient hydroxyapatite: An ab-initio analysis

    International Nuclear Information System (INIS)

    A systematic study of defect constellations in calcium-deficient hydroxyapatite is reported. Along this line, we explore different arrangements for charge compensation, including cationic vacancies and substitutional defects. The overall defect constellation is governed by both the different proton affinity of the anions or energy costs related to vacancy formation and minimization of the Coulomb energy which implies small distances of the anionic and cationic defects. Depending on the type of the calcium-deficient site, this gives rise to two specific defect arrangements. Among these, the calcium ions forming triangles which embed the OH- ions of hydroxyapatite are most likely to be deficient. The resulting charge is compensated by protonation of the OH- ion within the deficient calcium-triangle and protonation of a PO43- ion in the nearest neighbourhood of the vacant calcium site. The strong energetic favouring of such constellations indicates that the commonly used chemical formulae Ca10-x(HPO4)x(PO4)6-x(OH)2-x(H2O)x (02O defect and a HPO42- defect adjacent to the deficient Ca site. The preferential defect arrangement reflects a compromise of local charge compensation, different proton affinities of the anions and hydrogen bonding

  18. Longevity of dental amalgam in comparison to composite materials

    Directory of Open Access Journals (Sweden)

    Windisch, Friederike

    2008-11-01

    Full Text Available Health political background: Caries is one of the most prevalent diseases worldwide. For (direct restaurations of carious lesions, tooth-coloured composite materials are increasingly used. The compulsory health insurance pays for composite fillings in front teeth; in posterior teeth, patients have to bear the extra cost. Scientific background: Amalgam is an alloy of mercury and other metals and has been used in dentistry for more than one hundred and fifty years. Composites consist of a resin matrix and chemically bonded fillers. They have been used for about fifty years in front teeth. Amalgam has a long longevity; the further development of composites has also shown improvements regarding their longevity. Research questions: This HTA-report aims to evaluate the longevity (failure rate, median survival time (MST, median age of direct amalgam fillings in comparison to direct composite fillings in permanent teeth from a medical and economical perspective and discusses the ethical, legal and social aspects of using these filling materials. Methods: The systematic literature search yielded a total of 1,149 abstracts. After a two-step selection process based on defined criteria 25 publications remained to be assessed. Results: The medical studies report a longer longevity for amalgam fillings than for composite fillings. However, the results of these studies show a large heterogeneity. No publication on the costs or the cost-effectiveness of amalgam and composite fillings exists for Germany. The economic analyses (NL, SWE, GB report higher costs for composite fillings when longevity is assumed equal (for an observation period of five years or longer for amalgam compared to composite fillings. These higher costs are due to the higher complexity of placing composite fillings. Discussion: Due to different study designs and insufficient documentation of study details, a comparison of different studies on longevity of direct amalgam and composite

  19. High Strain Rate Characterisation of Composite Materials

    DEFF Research Database (Denmark)

    Eriksen, Rasmus Normann Wilken

    -reinforced polymers, were considered, and it was first shown that the loading history controls equilibrium process. Then the High-speed servo-hydraulic test machine was analysed in terms its ability to create a state of constant strain rate in the specimen. The invertible inertial forces in the load train prevented a...... linear elastic specimen to reach a state of constant strain rate before fracture. This was in contrast to ductile materials, which are widely tested with for the High-speed servohydraulic test machine. The development of the analysis and the interpretation of the results, were based on the experience...... from designing and constructing a high-speed servo-hydraulic test machine and by performing a comprehensive test series. The difficulties encountered in the test work could be addressed with the developed analysis. The conclusion was that the High-speed servo-hydraulic test machine is less suited for...

  20. Modern composite materials manufactured by pressure infiltration method

    OpenAIRE

    L.A. Dobrzański; M. Kremzer; M. Drak

    2008-01-01

    Purpose: The purpose of this paper is to present the technique of manufacturing the composite materials based on porous ceramic preforms infiltrated by liquid aluminium alloy and examination of the structure and corrosion resistance of those materials.Design/methodology/approach: The material for investigations was manufactured by pressure infiltration method of ceramic porous preforms. The eutectic aluminium alloy EN AC – AlSi12 was use as a matrix while as reinforcement were used...

  1. Left-handed materials in metallic magnetic granular composites

    OpenAIRE

    Chui, S. T.; Lin, Z. F.; Hu, L. -B.

    2003-01-01

    There is recently interests in the ``left-handed '' materials. In these materials the direction of the wave vector of electromagnetic radiation is opposite to the direction of the energy flow. We present simple arguments that suggests that magnetic composites can also be left-handed materials. However, the physics involved seems to be different from the original argument. In our argument, the imaginary part of the dielectric constant is much larger than the real part, opposite to the original...

  2. Tribology of ceramics and composites materials science perspective

    CERN Document Server

    Basu, Bikramjit

    2011-01-01

    This book helps students and practicing scientists alike understand that a comprehensive knowledge about the friction and wear properties of advanced materials is essential to further design and development of new materials. With important introductory chapters on the fundamentals, processing, and applications of tribology, the book then examines in detail the nature and properties of materials, the friction and wear of structural ceramics, bioceramics, biocomposites, and nanoceramics, as well as lightweight composites and the friction and wear of ceramics in a cryogenic environment.

  3. Microstructural Characterisation and Wear Behaviour of Diamond Composite Materials

    Directory of Open Access Journals (Sweden)

    Xing S. Li

    2010-02-01

    Full Text Available Since the initial research leading to the production of diamond composite materials, there have been several important developments leading to significant improvements in the properties of these superhard composite materials. Apart from the fact that diamonds, whether originating from natural resources or synthesised commercially, are the hardest and most wear-resistant materials commonly available, there are other mechanical properties that limit their industrial application. These include the low fracture toughness and low impact strength of diamond. By incorporating a range of binder phases into the sintering production process of these composites, these critically important properties have been radically improved. These new composites can withstand much higher operating temperatures without markedly reducing their strength and wear resistance. Further innovative steps are now being made to improve the properties of diamond composites by reducing grain and particle sizes into the nano range. This review will cover recent developments in diamond composite materials with special emphasis on microstructural characterisation. The results of such studies should assist in the design of new, innovative diamond tools as well as leading to radical improvements in the productivity of cutting, drilling and sawing operations in the exploration, mining, civil construction and manufacturing industries.

  4. Composites Materials and Manufacturing Technologies for Space Applications

    Science.gov (United States)

    Vickers, J. H.; Tate, L. C.; Gaddis, S. W.; Neal, R. E.

    2016-01-01

    Composite materials offer significant advantages in space applications. Weight reduction is imperative for deep space systems. However, the pathway to deployment of composites alternatives is problematic. Improvements in the materials and processes are needed, and extensive testing is required to validate the performance, qualify the materials and processes, and certify components. Addressing these challenges could lead to the confident adoption of composites in space applications and provide spin-off technical capabilities for the aerospace and other industries. To address the issues associated with composites applications in space systems, NASA sponsored a Technical Interchange Meeting (TIM) entitled, "Composites Materials and Manufacturing Technologies for Space Applications," the proceedings of which are summarized in this Conference Publication. The NASA Space Technology Mission Directorate and the Game Changing Program chartered the meeting. The meeting was hosted by the National Center for Advanced Manufacturing (NCAM)-a public/private partnership between NASA, the State of Louisiana, Louisiana State University, industry, and academia, in association with the American Composites Manufacturers Association. The Louisiana Center for Manufacturing Sciences served as the coordinator for the TIM.

  5. Growth and characterization of triglycine calcium dibromide, a semiorganic NLO material

    Energy Technology Data Exchange (ETDEWEB)

    Dhanaraj, P.V. [Centre for Crystal Growth, SSN College of Engineering, Kalavakkam 603 110 (India); Rajesh, N.P., E-mail: rajeshnp@ssn.edu.i [Centre for Crystal Growth, SSN College of Engineering, Kalavakkam 603 110 (India)

    2010-10-01

    Single crystals of semiorganic material triglycine calcium dibromide (TGCB) were grown from aqueous solution. The solubility and metastable zone width were found. Single crystal X-ray diffraction analysis was used to estimate the cell parameters of the grown crystals. The structural perfection of crystals has been analyzed by high-resolution X-ray diffraction (HRXRD) rocking curve measurements. Energy dispersive X-ray analysis confirms the presence of elements in the title compound. The grown crystals were tested by FTIR, thermogravimetric and differential thermal analysis, UV-vis-NIR analysis, and dielectrical and mechanical studies. The transmittance of TGCB crystal has been used to calculate the refractive index n, the extinction coefficient K and both the real {epsilon}{sub r} and imaginary {epsilon}{sub i} components of the dielectric constant as functions of wavelength. The second harmonic conversion efficiency of TGCB was determined using the Kurtz and Perry powder technique; it was observed to be greater than that of KDP.

  6. Composite Materials for Hazard Mitigation of Reactive Metal Hydrides.

    Energy Technology Data Exchange (ETDEWEB)

    Pratt, Joseph William; Cordaro, Joseph Gabriel; Sartor, George B.; Dedrick, Daniel E.; Reeder, Craig L.

    2012-02-01

    In an attempt to mitigate the hazards associated with storing large quantities of reactive metal hydrides, polymer composite materials were synthesized and tested under simulated usage and accident conditions. The composites were made by polymerizing vinyl monomers using free-radical polymerization chemistry, in the presence of the metal hydride. Composites with vinyl-containing siloxane oligomers were also polymerized with and without added styrene and divinyl benzene. Hydrogen capacity measurements revealed that addition of the polymer to the metal hydride reduced the inherent hydrogen storage capacity of the material. The composites were found to be initially effective at reducing the amount of heat released during oxidation. However, upon cycling the composites, the mitigating behavior was lost. While the polymer composites we investigated have mitigating potential and are physically robust, they undergo a chemical change upon cycling that makes them subsequently ineffective at mitigating heat release upon oxidation of the metal hydride. Acknowledgements The authors would like to thank the following people who participated in this project: Ned Stetson (U.S. Department of Energy) for sponsorship and support of the project. Ken Stewart (Sandia) for building the flow-through calorimeter and cycling test stations. Isidro Ruvalcaba, Jr. (Sandia) for qualitative experiments on the interaction of sodium alanate with water. Terry Johnson (Sandia) for sharing his expertise and knowledge of metal hydrides, and sodium alanate in particular. Marcina Moreno (Sandia) for programmatic assistance. John Khalil (United Technologies Research Corp) for insight into the hazards of reactive metal hydrides and real-world accident scenario experiments. Summary In an attempt to mitigate and/or manage hazards associated with storing bulk quantities of reactive metal hydrides, polymer composite materials (a mixture of a mitigating polymer and a metal hydride) were synthesized and tested

  7. Composite desiccant material "CaCl2/Vermiculite/Saw wood": a new material for fresh water production from atmospheric air

    Science.gov (United States)

    Kumar, Manoj; Yadav, Avadhesh

    2016-04-01

    In this study a novel composite desiccant material "CaCl2/Vermiculite/Saw wood" have been synthesized and tested for the water generation from atmospheric air. The vermiculite- saw wood used as a host matrix and CaCl2 as a hygroscopic salt. A solar glass desiccant box type system with a collector area of 0.36 m2 has been used. Design parameters for water generation are height of glass from the desiccant material bed as 0.22 m, inclination in angle as 30º, the effective thickness of glass as 3 mm and number of glazing as single. It has been found that the concentration of calcium chloride is the most influencing factor for fresh water generation from atmospheric air. The maximum amount of water produced by using novel composite desiccant material is 195 ml/kg/day.

  8. Multifunctional Martian habitat composite material synthesized from in situ resources

    Science.gov (United States)

    Sen, S.; Carranza, S.; Pillay, S.

    2010-09-01

    The two primary requirements for a Martian habitat structure include effective radiation shielding against the Galactic Cosmic Ray (GCR) environment and sufficient structural and thermal integrity. To significantly reduce the cost associated with transportation of such materials and structures from earth, it is imperative that such building materials should be synthesized primarily from Martian in situ resources. This paper illustrates the feasibility of such an approach. Experimental results are discussed to demonstrate the synthesis of polyethylene (PE) from a simulated Martian atmosphere and the fabrication of a composite material using simulated Martian regolith with PE as the binding material. The radiation shielding effectiveness of the proposed composites is analyzed using results from radiation transport codes and exposure of the samples to high-energy beams that serve as a terrestrial proxy for the GCR environment. Mechanical and ballistic impact resistance properties of the proposed composite as a function of composition, processing parameters, and thermal variations are also discussed to evaluate the multifunctionality of such in situ synthesized composite materials.

  9. Data for accelerated degradation of calcium phosphate surface-coated polycaprolactone and polycaprolactone/bioactive glass composite scaffolds

    OpenAIRE

    Poh, Patrina S.P.; Hutmacher, Dietmar W.; Holzapfel, Boris M; Solanki, Anu K.; Woodruff, Maria A.

    2016-01-01

    Polycaprolactone (PCL)-based composite scaffolds containing 50 wt% of 45S5 bioactive glass (45S5) or strontium-substituted bioactive glass (SrBG) particles were fabricated into scaffolds using melt-extrusion based additive manufacturing technique. Additionally, the PCL scaffolds were surface coated with a layer of calcium phosphate (CaP). For a comparison of the scaffold degradation, the scaffolds were then subjected to in vitro accelerated degradation by immersion in 5 M sodium hydroxide (Na...

  10. Wich Parameter of the Carbonate System Influences the Boron Isotopic Composition and the Boron Calcium Ratio in Foraminiferal Tests?

    Science.gov (United States)

    Kaczmarek, K.; Nehrke, G.; Horn, I.; Langer, G.; Misra, S.; Bijma, J.

    2013-12-01

    We performed culture experiments with the benthic symbiont bearing foraminifer Amphistegina lessonii in order to determine which parameter of the marine carbonate system influences the boron isotopic composition (δ11B) and the boron calcium ratio (B/Ca) in the test. A. lessonii grew for two months in treatments of culture media with decoupled pH-carbonate chemistry. We measured δ11B and B/Ca simultaneously on single tests using a recently new developed mass spectrometric technique. Our results show a clear pH dependence on δ11B. The B/Ca in the shell show a positive correlation with aqueous B(OH)4-/HCO3-.

  11. Performance of the Cement Matrix Composite Material With Rubber Powder

    Institute of Scientific and Technical Information of China (English)

    SONG Shao-min; LIU Juan-hong; ZHANG Xi-qing

    2004-01-01

    The effect of the deferent rubber content substituted for fine aggregate on the mortar performancewas studied. The effects of the rubber coated with the coating materials on the mortar compressive strength, bendingstrength and impact work were discussed. The optimum rubber powder content and the suitable coating materialwere found. Through the electrical probe test- BEI, SEI and calcium ion distribution, and the slight crack and theinterface between the rubber and cement matrix are analyzed. The results show that the rubber powder coated withthe surface treatment materials A, B and C bas the capability of absorbing a large amount of energy under thecompressive and flexural load and the slight cracks of R- C were controlled and restrained.

  12. Improved Composites Using Crosslinked, Surface-Modified Carbon Nanotube Materials

    Science.gov (United States)

    Baker, James Stewart

    2014-01-01

    Individual carbon nanotubes (CNTs) exhibit exceptional tensile strength and stiffness; however, these properties have not translated well to the macroscopic scale. Premature failure of bulk CNT materials under tensile loading occurs due to the relatively weak frictional forces between adjacent CNTs, leading to poor load transfer through the material. When used in polymer matrix composites (PMCs), the weak nanotube-matrix interaction leads to the CNTs providing less than optimal reinforcement.Our group is examining the use of covalent crosslinking and surface modification as a means to improve the tensile properties of PMCs containing carbon nanotubes. Sheet material comprised of unaligned multi-walled carbon nanotubes (MWCNT) was used as a drop-in replacement for carbon fiber in the composites. A variety of post-processing methods have been examined for covalently crosslinking the CNTs to overcome the weak inter-nanotube shear interactions, resulting in improved tensile strength and modulus for the bulk sheet material. Residual functional groups from the crosslinking chemistry may have the added benefit of improving the nanotube-matrix interaction. Composites prepared using these crosslinked, surface-modified nanotube sheet materials exhibit superior tensile properties to composites using the as received CNT sheet material.

  13. Barium and calcium borate glasses as shielding materials for x rays and gamma rays

    DEFF Research Database (Denmark)

    Singh, H.; Singh, K.; Sharma, G.;

    2003-01-01

    Values of the gamma-ray, mass attenuation coefficient and the effective atomic number have been determined experimentally for xBaO.(1-x) B2O3 (x=0.24, 0.30, 0.34,0.40 and 0.44) and xCaO. (I-x)B2O3 (x=0.30 and 0.40) glasses at photon energies 356, 511, 662, 1173, and 1332 keV It is pointed out that...... these glasses are potential radiation shielding materials. The specific volume of the glasses has been derived from density measurements and studied as a function of composition....

  14. Does the bracket composition material influence initial biofilm formation?

    OpenAIRE

    Gustavo Antônio Martins Brandão; Antonio Carlos Pereira; Ana Maria Martins Brandão; Haroldo Amorim de Almeida; Rogério Heládio Lopes Motta

    2015-01-01

    Context: Orthodontic treatment has been reported to contribute to the development and accumulation of dental biofilm, which is commonly found on bracket and adjacent surfaces. Aims: The aim of this work is to test the hypothesis if there are differences in dental biofilm formation on the surface of orthodontic brackets according to the type of composition material. Subjects and Methods: Three bracket types (metallic, composite, and ceramic) had been evaluated. Subjects wore acrylic pa...

  15. NON DESTRUCTIVE EVALUATION OF COMPOSITE MATERIALS USING ULTRASONIC SPECTROSCOPY

    OpenAIRE

    Ourak, M.; Nongaillard, B.; Rouvaen, J.; Imouloudene, N.

    1990-01-01

    The non destructive evaluation of the carbon epoxy composite materials (often used in aeronautics) is a difficult matter. The classical control methods prove unsatisfactory for the detection of distributed defects (like delaminations and porosities), which affect severely the mechanical properties of composite parts. Ultrasonic echography (A scan mode) allows for the detection of some kinds of delaminations, but the interpretation of the echographic signal remains difficult in the case of por...

  16. Radiation processed composite materials of wood and elastic polyester resins

    International Nuclear Information System (INIS)

    The radiation polymerization of multifunctional unsaturated polyester-monomer mixtures in wood forms interpenetrating network system. The mechanical resistance (compression, abrasion, hardness, etc.) of these composite materials are generally well over the original wood, however the impact strength is almost the same or even reduced, in comparison to the wood itself. An attempt is made using elastic polyester resins to produced wood-polyester composite materials with improved modulus of elasticity and impact properties. For the impregnation of European beech wood two types of elastic unsaturated polyester resins were used. The exothermic effect of radiation copolymerization of these resins in wood has been measured and the dose rate effects as well as hardening dose was determined. Felxural strength and impact properties were examined. Elastic unsaturated polyester resins improved the impact strength of wood composite materials. (author)

  17. The fabrication of nanocomposites via calcium phosphate formation on gelatin–chitosan network and the gelatin influence on the properties of biphasic composites

    International Nuclear Information System (INIS)

    A novel biodegradable polymer–ceramic nanocomposite which consisted of gelatin (Gel), chitosan (CS), and calcium phosphate (CaP) nanoparticles was prepared based on in situ preparation method. The fabricated biocomposites were characterized by FTIR, X-ray diffraction (XRD), transmission electron microscopy (TEM) as well as scanning electron microscope with X-ray elemental analysis (SEM-EDX). The characterization results confirmed that the crystalline calcium phosphate nanoparticles were mineralized in polymeric matrix and the interaction between Ca2+ in calcium phosphate and functional groups in polymers molecular chains was formed. XRD result showed that in addition to hydroxyapatite (HA), Brushite (BR) and tricalcium phosphate (β-TCP) particles also were formed due to lack of complete penetration of the basic solution into the polymeric matrix. However, SEM image indicated that the polymeric matrix has the controlling role in the particle size of calcium phosphate. The size of particles in three component composites was about 100 nm while in two component composites proved to be more in μm size. TEM observation supported SEM results and showed that the three component composites have calcium phosphate nanoparticles. The elastic modulus and compressive strength of the composites were also improved by the employment of gelatin and chitosan together, which can make them more beneficial for surgical applications. - Highlights: ► A new type of calcium phosphate nanocomposites consisted chitosan and gelatin as polymeric matrix was obtained via in situ precipitation method. ► The formed particles into the polymeric matrix are hydroxyapatite, Brushite and β-tricalcium phosphate. ► The polymer concentration is a predominant factor for inhibiting nucleation and growth of calcium phosphate particles as the particles size was also decreased by increasing the amount of polymeric phase. ► The nano particles formed in three component composites and micro particles

  18. The fabrication of nanocomposites via calcium phosphate formation on gelatin-chitosan network and the gelatin influence on the properties of biphasic composites

    Energy Technology Data Exchange (ETDEWEB)

    Babaei, Zahra [Nanotechnology Research Institute, School of Chemical Engineering, Babol University of Technology, Babol (Iran, Islamic Republic of); Jahanshahi, Mohsen, E-mail: mjahan@nit.ac.ir [Nanotechnology Research Institute, School of Chemical Engineering, Babol University of Technology, Babol (Iran, Islamic Republic of); Rabiee, Sayed Mahmood [Nanotechnology Research Institute, School of Chemical Engineering, Babol University of Technology, Babol (Iran, Islamic Republic of); School of Mechanical Engineering, Babol University of Technology, Babol (Iran, Islamic Republic of)

    2013-01-01

    A novel biodegradable polymer-ceramic nanocomposite which consisted of gelatin (Gel), chitosan (CS), and calcium phosphate (CaP) nanoparticles was prepared based on in situ preparation method. The fabricated biocomposites were characterized by FTIR, X-ray diffraction (XRD), transmission electron microscopy (TEM) as well as scanning electron microscope with X-ray elemental analysis (SEM-EDX). The characterization results confirmed that the crystalline calcium phosphate nanoparticles were mineralized in polymeric matrix and the interaction between Ca2+ in calcium phosphate and functional groups in polymers molecular chains was formed. XRD result showed that in addition to hydroxyapatite (HA), Brushite (BR) and tricalcium phosphate ({beta}-TCP) particles also were formed due to lack of complete penetration of the basic solution into the polymeric matrix. However, SEM image indicated that the polymeric matrix has the controlling role in the particle size of calcium phosphate. The size of particles in three component composites was about 100 nm while in two component composites proved to be more in {mu}m size. TEM observation supported SEM results and showed that the three component composites have calcium phosphate nanoparticles. The elastic modulus and compressive strength of the composites were also improved by the employment of gelatin and chitosan together, which can make them more beneficial for surgical applications. - Highlights: Black-Right-Pointing-Pointer A new type of calcium phosphate nanocomposites consisted chitosan and gelatin as polymeric matrix was obtained via in situ precipitation method. Black-Right-Pointing-Pointer The formed particles into the polymeric matrix are hydroxyapatite, Brushite and {beta}-tricalcium phosphate. Black-Right-Pointing-Pointer The polymer concentration is a predominant factor for inhibiting nucleation and growth of calcium phosphate particles as the particles size was also decreased by increasing the amount of polymeric

  19. Silver nanowire array-polymer composite as thermal interface material

    Science.gov (United States)

    Xu, Ju; Munari, Alessio; Dalton, Eric; Mathewson, Alan; Razeeb, Kafil M.

    2009-12-01

    Silver nanowire arrays embedded inside polycarbonate templates are investigated as a viable thermal interface material for electronic cooling applications. The composite shows an average thermal diffusivity value of 1.89×10-5 m2 s-1, which resulted in an intrinsic thermal conductivity of 30.3 W m-1 K-1. The nanowires' protrusion from the film surface enables it to conform to the surface roughness to make a better thermal contact. This resulted in a 61% reduction in thermal impedance when compared with blank polymer. An ˜30 nm Au film on the top of the composite was found to act as a heat spreader, reducing the thermal impedance further by 35%. A contact impedance model was employed to compare the contact impedance of aligned silver nanowire-polymer composites with that of aligned carbon nanotubes, which showed that the Young's modulus of the composite is the defining factor in the overall thermal impedance of these composites.

  20. A LOWER BOUND LIMIT ANALYSIS OF DUCTILE COMPOSITE MATERIALS

    Institute of Scientific and Technical Information of China (English)

    Zhang Hongtao; Liu Yinghua; Xu Bingye

    2005-01-01

    The plastic load-bearing capacity of ductile composites such as metal matrix composites is studied with an insight into the microstructures. The macroscopic strength of a composite is obtained by combining the homogenization theory with static limit analysis, where the temperature parameter method is used to construct the self-equilibrium stress field. An interface failure model is proposed to account for the effects of the interface on the failure of composites.The static limit analysis with the finite-element method is then formulated as a constrained nonlinear programming problem, which is solved by the Sequential Quadratic Programming (SQP)method. Finally, the macroscopic transverse strength of perforated materials, the macroscopic transverse and off-axis strength of fiber-reinforced composites are obtained through numerical calculation. The computational results are in good agreement with the experimental data.

  1. Hot extruded carbon nanotube reinforced aluminum matrix composite materials

    Science.gov (United States)

    Kwon, Hansang; Leparoux, Marc

    2012-10-01

    Carbon nanotube (CNT) reinforced aluminum (Al) matrix composite materials were successfully fabricated by mechanical ball milling followed by powder hot extrusion processes. Microstructural analysis revealed that the CNTs were well dispersed at the boundaries and were aligned with the extrusion direction in the composites obtained. Although only a small quantity of CNTs were added to the composite (1 vol%), the Vickers hardness and the tensile strength were significantly enhanced, with an up to three-fold increase relative to that of pure Al. From the fractography of the extruded Al-CNT composite, several shapes were observed in the fracture surface, and this unique morphology is discussed based on the strengthening mechanism. The damage in the CNTs was investigated with Raman spectroscopy. However, the Al-CNT composite materials were not only strengthened by the addition of CNTs but also enhanced by several synergistic effects. The nanoindentation stress-strain curve was successfully constructed by setting the effective zero-load and zero-displacement points and was compared with the tensile stress-strain curve. The yield strengths of the Al-CNT composites from the nanoindentation and tensile tests were compared and discussed. We believe that the yield strength can be predicted using a simple nanoindentation stress/strain curve and that this method will be useful for materials that are difficult to machine, such as complex ceramics.

  2. Hot extruded carbon nanotube reinforced aluminum matrix composite materials

    International Nuclear Information System (INIS)

    Carbon nanotube (CNT) reinforced aluminum (Al) matrix composite materials were successfully fabricated by mechanical ball milling followed by powder hot extrusion processes. Microstructural analysis revealed that the CNTs were well dispersed at the boundaries and were aligned with the extrusion direction in the composites obtained. Although only a small quantity of CNTs were added to the composite (1 vol%), the Vickers hardness and the tensile strength were significantly enhanced, with an up to three-fold increase relative to that of pure Al. From the fractography of the extruded Al–CNT composite, several shapes were observed in the fracture surface, and this unique morphology is discussed based on the strengthening mechanism. The damage in the CNTs was investigated with Raman spectroscopy. However, the Al–CNT composite materials were not only strengthened by the addition of CNTs but also enhanced by several synergistic effects. The nanoindentation stress–strain curve was successfully constructed by setting the effective zero-load and zero-displacement points and was compared with the tensile stress–strain curve. The yield strengths of the Al–CNT composites from the nanoindentation and tensile tests were compared and discussed. We believe that the yield strength can be predicted using a simple nanoindentation stress/strain curve and that this method will be useful for materials that are difficult to machine, such as complex ceramics. (paper)

  3. Studying microstructure and phase composition of a new complex calcium containing alloy

    Directory of Open Access Journals (Sweden)

    I. Bartenev

    2016-10-01

    Full Text Available In the given article there are presented the results of studying the microstructure and phase structure of a complex alloy of alumosilicon with calcium. It is established that in the studied CAMS alloy active elements are present at a type of difficult intermetallid that positively influences quality of both ordinary, and qualitative brands of steel.

  4. Boron carbide composite carbon material, method of manufacturing the same and plasma facing material

    International Nuclear Information System (INIS)

    A boron carbide composite material of the present invention is formed by compositing boron carbide, which is a material suitable as a plasma facing material especially for a thermonuclear reactor. Boron carbide is filled in open cells of a carbon fiber-carbon composite material containing carbon fibers and a carbon matrix. In addition, a boron carbide film is formed on the surface of the composite material. A CVD method and a plasma flaming method are generally known, but they involve problems of occurrence of cracks and peeling of coating film due to thermal stresses. Then, a boron compound is chemically reacted with the surface of a carbon material to convert the carbon on the surface to boron carbide. The composite material contains carbon fibers oriented in one direction, and a boron carbide coating film is formed on the plasma facing surface. With such a constitution, there can be obtained a useful plasma facing material which has excellent strength especially in the direction of the fibers and having heat resistance, chemical stability and ware resistance even after the boron carbide coating film is exhausted and the base material is exposed. (T.M.)

  5. Composite materials of the aluminium-steel system

    International Nuclear Information System (INIS)

    Data on development and production of new composite materials with different aluminium matrices (SAP-1, AD1, AB), reinforced by high-strength wires of VNS-9 steel are given. Three methods of composite material production are applied: explosion welding, hot rolling in vacuum, diffusion sintering. Advantages and disadvantages of each of these methods are given. SAP1+VNS-9 steel wire composite is promising for constructions, operating under high temperature conditions (400-500 deg C). It is stated that at the temperature of 400 deg C short-time strength of reinforced SAP-1 is higher to 85 kgs/mm2, i.e. 12 times higher than the strength of non-reinforced one. The KAS-1A composite material based on heat matrix of AB alloy permitted to increase the strength of the A the transverse direction by 15-20 kgs/mm2. The KAS-1 and KAS-1 composite materials are considered to be promising for using as coverings of different slapes to strengthen constructions (to decrease a crack propagation rate)

  6. In Vitro Cytotoxicity of Calcium Silicate-Based Endodontic Cement as Root-End Filling Materials

    OpenAIRE

    Selen Küçükkaya; Mehmet Ömer Görduysus; Naciye Dilara Zeybek; Sevda Fatma Müftüoğlu

    2016-01-01

    The aim of this study was to evaluate the cytotoxicity of three types of calcium silicate-based endodontic cement after different incubation periods with human periodontal ligament fibroblasts. Human periodontal ligament fibroblasts were cultured from extracted third molars and seeded in 96-well plates. MTA, calcium enriched mixture (CEM) cement, and Biodentine were prepared and added to culture insert plates which were immediately placed into 96-well plates containing cultured cells. After i...

  7. Comparing Titanium Release from Ceramic Tiles using a waste material characterization test - Influence of Calcium and Organic Matter concentrations

    DEFF Research Database (Denmark)

    Heggelund, Laura Roverskov; Hansen, Steffen Foss; Astrup, Thomas Fruergaard;

    2015-01-01

    deposited in landfills for construction and demolition waste or other types of landfills, depending on the local waste management system. Hence, the potential release of nano-Ti under landfill conditions is relevant to investigate. In this study we used a standard waste material characterization method to...... waste material to the landfill leachate, it is expected that the calcium and organic matter content in the liquid will affect the stability of the nanoparticles. The concentration of calcium in the landfill percolate is expected to decrease the stability of the particles due to compression of the...... immediately after the 24 hrs. test using single particle ICPMS and Transmission Electron Microscopy imaging. The preliminary results suggest that nanoparticulate titanium is released from both tiles – with and without nano-titanium dioxide coating. The size distributions of the released particles are similar...

  8. Bioactivity and degradability of hybrids nano-composites materials with great application as bone tissue substitutes

    Energy Technology Data Exchange (ETDEWEB)

    Sánchez-Téllez, D.A.; Téllez-Jurado, L.; Chávez-Alcalá, J.F., E-mail: fchaveza@hotmail.com

    2014-12-05

    Highlights: • pH has an effect on the degradation process of the hybrid materials. • Weight loss depends on the change of pH during the degradation process. • Bioactivity in the materials is strongly related to calcium and pH. - Abstract: In this work, hybrids with great application as bioactive materials having different compositions based on siloxane network were prepared. In vitro bioactivity and in vitro degradability tests were carried out in the materials by soaking them into simulated body fluid (SBF) and into phosphate buffer solution (PBS) to prove their apatite-forming ability and to show their degradation process, respectively. In both in vitro tests, measurements of pH and loss weight were made to observe bioactivity and degradation processes. To prove growth of HA, the materials were characterized through X-ray diffraction, infrared spectroscopy, and scanning electron microscopy. The results showed that some samples have better bioactivity than others. It was found that the incorporation of CaO component into the network of the materials results in an increase of the apatite-forming ability in SBF. Moreover, during the degradation tests, all the samples presented weight loss, especially the ones that contain CaO.

  9. Orthogonal cutting characteristics of graphite/epoxy composite material

    Science.gov (United States)

    Wang, D. H.; Ramulu, M.; Wern, C. W.

    Orthogonal cutting experimental study was conducted to investigate the machining characteristics of Graphite/Epoxy (Gr/Ep) composite material. Machining characteristics were evaluated in terms of cutting forces, chip formation, and surface morphology of unidirectional Gr/Ep composite material of different fiber orientations. The cutting forces were measured by a three-dimensional circular-type dynamometer. Chips were examined under Scanning Electron Microscopy (SEM) and the machined surface morphology was investigated by measuring the surface roughness and by observing SEM photographs. Cutting forces, chip formation process and the surface morphology of machined surface were found to be highly dependent on the fiber orientations with respect to the cutting direction.

  10. Preparation of Nano/Micron Composite Materials by Process Method

    Institute of Scientific and Technical Information of China (English)

    GAN Ai-feng; WEI Qi; JI; Yuan; HU Chuan-xin; YAO Jun-min

    2004-01-01

    This thesis put forward a method that controls the process of synthesizing nanomaterial to realize the composite of nanomaterial and micronmaterial. This thesis realizes the composite of nanomaterial and micronmaterial by adding micronmaterial during production of nanomaterial through sol-gel method, also introduces the technique and experiment's process preparation of nanocomposite material, and successfully prepared nanocomposite materials with nano-PbTiO3 covered on the surface of micron-Ni. According to the sample's SEM-pictures, the core-shell can be observed plate microstructure, and it is uniform, tight, full and good.

  11. Tetracycline Loaded Collagen/Hydroxyapatite Composite Materials for Biomedical Applications

    Directory of Open Access Journals (Sweden)

    Laura Cristina Rusu

    2015-01-01

    Full Text Available The paper describes the preparation, characterisation, and testing of tetracycline loaded collagen-carboxymethylcellulose/hydroxyapatite ternary composite materials. The synthesis of this drug delivery system consists in two steps: the first step is the mineralization of collagen-carboxymethylcellulose gel while the second step corresponds to the loading of the ternary composite material with tetracycline. The obtained DDS is characterised by physicochemical, morphological, and release behaviour by using FTIR spectroscopy and microscopy, scanning electron microscopy, and UV-VIS spectroscopy. Based on the release study, it can be assumed that tetracycline is released in a prolonged way, assuring at least 6 days of antiseptic properties.

  12. Composite magnetostrictive materials for advanced automotive magnetomechanical sensors

    International Nuclear Information System (INIS)

    In this paper we present the development of a composite magnetostrictive material for automotive applications. The material is based on cobalt ferrite, CoO centre dot Fe2O3, and contains a small fraction of metallic matrix phase that serves both as a liquid phase sintering aid during processing and enhances the mechanical properties over those of a simple sintered ferrite ceramic. In addition the metal matrix makes it possible to braze the material making the assembly of a sensor relatively simple. The material exhibits good sensitivity and should have high corrosion resistance while at the same time it is low cost

  13. Soil Surface Composition Effects on the Wettability of Aquifer Materials

    Science.gov (United States)

    Ryder, J. L.; Demond, A. H.

    2004-05-01

    The wettability of subsurface porous media is critical for determining the distribution of non-aqueous phase liquids. Variations in the wettability of subsurface materials are generally attributed to sorption of hydrophobic contaminants. However, naturally occurring carbonaceous materials may influence the wettability as well. A series of seven soil materials were selected to determine the effect of organic carbon surfaces on soil wetting behavior. The materials represent organic carbon containing surfaces that may be found in soils from young humic matter to mature coal and shale kerogen. Measurements of organic liquid-water contact angle against cut rock faces reveal that surface composition alters the contact angle from the completely water wetted condition of quartz in the case of the mature carbon materials (Lachine Shale, Garfield Shale, Waynesburg Coal, and Plumbago Mineral Carbon). An examination of the soil elemental composition confirms that the bulk elemental composition of each material is separated on a plot of hydrogen to carbon versus oxygen to carbon ratios. The functional groups present at the surface of the soil materials were obtained with Fourier Transform Infrared Spectroscopy (FT-IR) analysis and indicate that the presence of oxygen containing surface functional groups is positively correlated with increased organic-liquid wetting. This study demonstrates that even in the absence of sorbing contaminants the subsurface is fractionally water-wet. This finding may help explain why subsurface distributions of non aqueous phase liquids can vary from those determined with laboratory sands.

  14. Silicon carbide composites as fusion power reactor structural materials

    International Nuclear Information System (INIS)

    Silicon carbide was first proposed as a low activation fusion reactor material in the mid 1970s. However, serious development of this material did not begin until the early 1990s, driven by the emergence of composite materials that provided enhanced toughness and an implied ability to use these typically brittle materials in engineering application. In the decades that followed, SiC composite system was successfully transformed from a poorly performing curiosity into a radiation stable material of sufficient maturity to be considered for near term nuclear and non-nuclear systems. In this paper the recent progress in the understanding and of basic phenomenon related to the use of SiC and SiC composite in fusion applications will be presented. This work includes both fundamental radiation effects in SiC and engineering issues such as joining and general materials properties. Additionally, this paper will briefly discuss the technological gaps remaining for the practical application of this material system in fusion power devices such as DEMO and beyond.

  15. Carbon materials as fillers for polymer matrix composites

    Directory of Open Access Journals (Sweden)

    J. Stabik

    2012-01-01

    Full Text Available Purpose: Paper presents different types of carbon materials used as modifiers for polymer matrix composites. The article contains summary description of the available varieties of carbon materials from brown and hard coal to the carbon nanotubes and fullerenes.Design/methodology/approach: The aim of the publication is to present different forms of carbon materials, their origins and ways of creation. Paper summarizes also basic properties and possible applications of carbon materials as components of engineering polymeric composites.Findings: Paper especially focuses on types of hard coal (mine coal as potential fillers for polymers. These materials and their properties and applications were studied in detail by the authors in previous researches.Research limitations/implications: Analysis of the literature and authors’ own research results indicate that carbon materials as fillers can essentially improve many different properties of polymer matrix composites but still have to be extensively searched to fully evaluate their characteristics and possible applications.Practical implications: Particular attention should be directed to the use of mined coal as a properties modifier of polymers because of its interesting properties, low prize and availability in Poland.Originality/value: New types of carbon materials as polymer fillers, their properties and application possibilities are presented.

  16. Composition adjustment of low activation materials for shallow land burial

    International Nuclear Information System (INIS)

    The three representative low activation materials for a fusion reactor are ferritic steel, V-alloy and SiC/SiC composite. The adjustment of the material composition of these materials to increase the fraction of shallow land burial in Japan was considered. In Japan, the fission waste having any single radionuclide exceeding the limiting concentration value, causing 100 μSv year-1 individual dose, determined by the Nuclear Safety Commission will not qualify as a low level waste (LLW), which could be disposed by shallow land burial. The limiting concentration values of radionuclides produced in fusion reactor were derived based on the methodology of the Nuclear Safety Commission. Radionuclide concentrations of the radwastes generated from the fusion power reactors using the three low activation materials based on the composition of existing materials were evaluated. Radwastes are classified into LLW and medium level waste (MLW), which is defined as the waste which does not qualify for LLW because one or more of the radionuclides exceeds the derived limiting concentration value. The weight fraction of MLW among the sum of LLW and MLW is found to be 10% for ferritic steel, 54% for V-alloy and 43% for SiC/SiC. The possibility of decreasing the MLW fraction by the material composition adjustment is considered. It is found that if Nb impurity content in V-alloy and N impurity content in SiC/SiC composite could be reduced, the MLW fraction can be significantly decreased. On the other hand, the content of the alloy component material (W), needs to be reduced to further decrease the MLW fraction in case of the ferritic steel F82H

  17. Synthesis of calcium-deficient by hydroxyapatite-collage composite by the electrolytic deposition method; Denkai sekishutsu ho ni yoru karushiumu kesson hidorokishiapataito-coragen fukugotai no gosei

    Energy Technology Data Exchange (ETDEWEB)

    Okamura, H. [Niigata University, Niigata (Japan). Graduate School Of Science and Technology; Yasuda, M.; Oota, M. [Niigata University, Niigata (Japan)

    1997-07-05

    Hydroxyapatite is known as that it has a good joining property with teeth and bone, and a study on the application to the living body was conducted by using this property. Its application examples were given as the cement used in dentistry, the artificial tooth root, the artificial bone, the bone cement and the artificial joint. However, they were a sinter heated at more than 1000degC, and were put into use by means of reinforcement using a titanium alloy since their mechanical strength was low. In this study, synthesis of calcium-deficient hydroxyapatite (DAp) and collagen composite by the electrolytic deposition method was attempted in order to develop bionic materials, and the correlation of various physical properties of the obtained composite and the electrolytic deposition conditions were investigated. When the electrolytic voltage is more than 22.0V, a single phase of DAp could be obtained. It was clarified that a DAp and collagen composite was synthesized from results of IR and ESR. 16 refs., 5 figs.

  18. Poly(lactide-co-glycolide acid)/biphasic calcium phosphate composite coating on a porous scaffold to deliver simvastatin for bone tissue engineering.

    Science.gov (United States)

    Sadiasa, Alexander; Kim, Min Sung; Lee, Byong Taek

    2013-09-01

    In this study, simvastatin (SIM) drug incorporated poly(D,L-lactic-co-glycolide) (PLGA)/biphasic calcium phosphate (BCP) composite material (SPB) was coated on the BCP/ZrO2 (SPB-BCP/ZrO2) scaffold to enhance the mechanical and bioactive properties of the BCP/ZrO2 scaffold for bone engineering applications. The composite coating was prepared by combining different ratios of PLGA and BCP (1:2, 1:1, 2:1). After completion of the coating process, the compressive strength of the scaffolds was shown to increase with an increase in PLGA concentration from 8.5 ± 0.52 MPa for the SPB1-BCP/ZrO2 (1:2) to 11 ± 0.65 MPa for SPB3-BCP/ZrO2 (2:1) scaffolds when PLGA concentration was increased. Furthermore, the increase of PLGA in the coating composition corresponds to a decrease in porosity, degradation rate and weight loss of the scaffolds after 4 weeks. SIM release study demonstrated sustained release of the drug for the three kinds of scaffolds with improved biocompatibility. The increase of PLGA concentration also resulted in a lower release rate of SIM. Thus, the lower release rate of SIM brought upon by the increase of PLGA concentration further enhanced the performance of the scaffold in vitro making it a promising approach in the field of bone tissue regeneration. PMID:23815378

  19. Coronary artery calcium quantification from contrast enhanced CT using gemstone spectral imaging and material decomposition.

    Science.gov (United States)

    Fuchs, Tobias A; Stehli, Julia; Dougoud, Svetlana; Sah, Bert-Ram; Bull, Sacha; Clerc, Olivier F; Possner, Mathias; Buechel, Ronny R; Gaemperli, Oliver; Kaufmann, Philipp A

    2014-10-01

    To explore the feasibility of coronary artery calcium (CAC) measurement from low-dose contrast enhanced coronary CT angiography (CCTA) as this may obviate the need for an unenhanced CT scan. 52 patients underwent unenhanced cardiac CT and prospectively ECG triggered contrast enhanced CCTA (Discovery HD 750, GE Healthcare, Milwaukee, WI, USA). The latter was acquired in single-source dual-energy mode [gemstone spectral imaging (GSI)]. Virtual unenhanced images were generated from GSI CCTA by monochromatic image reconstruction of 70 keV allowing selective iodine material suppression. CAC scores from virtual unenhanced CT were compared to standard unenhanced CT including a linear regression model. After iodine subtraction from the contrast enhanced CCTA the attenuation in the ascending aorta decreased significantly from 359 ± 61 to 54 ± 8 HU (P < 0.001), the latter comparing well to the value of 64 ± 55 HU found in the standard unenhanced CT (P = ns) confirming successful iodine subtraction. After introducing linear regression formula the mean values for Agatston, Volume and Mass scores of virtual unenhanced CT were 187 ± 321, 72 ± 114 mm(3), and 27 ± 46 mg/cm(3), comparing well to the values from standard unenhanced CT (187 ± 309, 72 ± 110 mm(3), and 27 ± 45 mg/cm(3)) yielding an excellent correlation (r = 0.96, r = 0.96, r = 0.92; P < 0.001). Mean estimated radiation dose revealed 0.83 ± 0.02 mSv from the unenhanced CT and 1.70 ± 0.53 mSv from the contrast enhanced CCTA. Single-source dual-energy scanning with GSI allows CAC quantification from low dose contrast enhanced CCTA by virtual iodine contrast subtraction. PMID:24993390

  20. Justification of radiation protection fillers based composite materials fosfogipsum binding materials

    OpenAIRE

    Голов, Константин Сергеевич; Иванов, Валерий Анатолиевич; Мисовец, Юрий Викторович

    2012-01-01

    The results of comparative experimental studies of the effect of various radiation protection (RP) fillers of composite materials based on their fosfogipsum binding properties of RP From the analysis of results of experimental studies of the effect of various rare-earth filling of composite materials based on their binding fosfogipsum protective properties may be concluded. Barium sulfate as the RE filler plaster matrix displays technological instability in the manufacturing process of the co...

  1. Natural Kenaf Fiber Reinforced Composites as Engineered Structural Materials

    Science.gov (United States)

    Dittenber, David B.

    The objective of this work was to provide a comprehensive evaluation of natural fiber reinforced polymer (NFRP)'s ability to act as a structural material. As a chemical treatment, aligned kenaf fibers were treated with sodium hydroxide (alkalization) in different concentrations and durations and then manufactured into kenaf fiber / vinyl ester composite plates. Single fiber tensile properties and composite flexural properties, both in dry and saturated environments, were assessed. Based on ASTM standard testing, a comparison of flexural, tensile, compressive, and shear mechanical properties was also made between an untreated kenaf fiber reinforced composite, a chemically treated kenaf fiber reinforced composite, a glass fiber reinforced composite, and oriented strand board (OSB). The mechanical properties were evaluated for dry samples, samples immersed in water for 50 hours, and samples immersed in water until saturation (~2700 hours). Since NFRPs are more vulnerable to environmental effects than synthetic fiber composites, a series of weathering and environmental tests were conducted on the kenaf fiber composites. The environmental conditions studied include real-time outdoor weathering, elevated temperatures, immersion in different pH solutions, and UV exposure. In all of these tests, degradation was found to be more pronounced in the NFRPs than in the glass FRPs; however, in nearly every case the degradation was less than 50% of the flexural strength or stiffness. Using a method of overlapping and meshing discontinuous fiber ends, large mats of fiber bundles were manufactured into composite facesheets for structural insulated panels (SIPs). The polyisocyanurate foam cores proved to be poorly matched to the strength and stiffness of the NFRP facesheets, leading to premature core shear or delamination failures in both flexure and compressive testing. The NFRPs were found to match well with the theoretical stiffness prediction methods of classical lamination

  2. Design and Analysis of Leaf Spring with Composite materials

    OpenAIRE

    Mr. Tharigonda Niranjan Babu

    2014-01-01

    In automobile sector tends to increasing competition and innovation in design and tends to modify the existing products by new and advanced materials. Leaf springs are special kind of springs used in automobile suspension systems. The main function of leaf spring is not only to support vertical load but also to isolate road induced vibrations. It is subjected to millions of load cycles leading to fatigue failure. The introduction of composite materials has made it possible to ...

  3. A versatile composite material for fast neutron shielding

    International Nuclear Information System (INIS)

    Full text: A composite material which consists of polyethelyene granules and borax powder embedded in a polyester resin has been developed for the shielding of fast neutrons. The material is particularly suited to small to medium size installations and is currently being used as a replacement for boronated paraffin wax. Measurements have demonstrated that the shielding is comparable to boronated wax, while at the same time displaying superior mechanical properties

  4. Certification of the uranium hexafluoride reference materials for isotopic composition

    OpenAIRE

    MIALLE SÉBASTIEN; Richter, Stephan; HENNESSY Carmel; TRUYENS Jan; Jakobsson, Ulf; Aregbe, Yetunde

    2014-01-01

    The IRMM-019 to IRMM-029 series of uranium hexafluoride materials is certified for the isotopic composition. After conversion into uranyl nitrate solution, certification and homogeneity measurements were performed by Thermal Ionization Mass Spectrometry. Analyses were performed by Modified Total Evaporation and for some materials the major isotope amount ratio n(235U)/n(238U) was measured using a n(233U)/n(236U) double spike. Measurements were confirmed by UF6 Gas Source Mass Spectrometry. Ma...

  5. The effect of nanotopography on calcium and phosphorus deposition on metallic materials in vitro.

    Science.gov (United States)

    Ward, Brian C; Webster, Thomas Jay

    2006-06-01

    To date, long-term functions of osteoblasts leading to calcium and phosphorus mineral deposition on nanometals have not been determined. Nanometals are metals with constituent metal particles and/or surface features less than 100 nm in at least one dimension. For this reason, the objective of this in vitro study was to determine the amount of calcium and phosphorus mineral formation on microphase compared to nanophase Ti, Ti6Al4V, and CoCrMo cultured with and without osteoblasts (bone-forming cells). The results of this study provided the first evidence of significantly greater calcium and phosphorus deposition by osteoblasts and precipitation from culture media without osteoblasts on nanophase compared to respective microphase Ti6Al4V and CoCrMo after 21 days; the greatest calcium and phosphorus mineral deposition occurred on nanophase CoCrMo while the greatest calcium and phosphorus mineral precipitation without osteoblasts occurred on nanophase Ti6Al4V. No differences were found for any type of Ti: wrought, microphase, or nanophase. Moreover, increased calcium and phosphorus mineral content correlated to greater amounts of underlying aluminum content on Ti6Al4V surfaces. Since, compared to microphase Ti6Al4V, nanophase Ti6Al4V contained a higher amount of aluminum at the surface (due to greater surface area), this may provide a reason for enhanced calcium and phosphorus mineral content on nanophase Ti6Al4V. Regardless of the mechanism, this study continues to support the further investigation of nanometals for improved orthopedic applications. PMID:16476478

  6. High-Capacity, High-Voltage Composite Oxide Cathode Materials

    Science.gov (United States)

    Hagh, Nader M.

    2015-01-01

    This SBIR project integrates theoretical and experimental work to enable a new generation of high-capacity, high-voltage cathode materials that will lead to high-performance, robust energy storage systems. At low operating temperatures, commercially available electrode materials for lithium-ion (Li-ion) batteries do not meet energy and power requirements for NASA's planned exploration activities. NEI Corporation, in partnership with the University of California, San Diego, has developed layered composite cathode materials that increase power and energy densities at temperatures as low as 0 degC and considerably reduce the overall volume and weight of battery packs. In Phase I of the project, through innovations in the structure and morphology of composite electrode particles, the partners successfully demonstrated an energy density exceeding 1,000 Wh/kg at 4 V at room temperature. In Phase II, the team enhanced the kinetics of Li-ion transport and electronic conductivity at 0 degC. An important feature of the composite cathode is that it has at least two components that are structurally integrated. The layered material is electrochemically inactive; however, upon structural integration with a spinel material, the layered material can be electrochemically activated and deliver a large amount of energy with stable cycling.

  7. Analysis of Composite Material Blended With Thermoplastics and Jute Fibre

    Directory of Open Access Journals (Sweden)

    Venugopal S

    2015-03-01

    Full Text Available Recently natural fibres have been receiving considerable attention as substitutes for synthetic fibre reinforcements due to their low cost, low density, acceptable specific strength, good thermal insulation properties, reduced tool wear, reduced thermal and respiratory irritation and renewable resources. The aim of this work is to develop chemically treated and chemically untreated fibre reinforced composite material with optimum properties so that it can replace the existing synthetic fibre reinforced composite material for a suitable application. In this work, polyester resin has been reinforced with jute fabric, so as to develop jute fibre reinforced plastic (JFRP with a weight ratio of 10:1:1 Hand lay-up technique was used to manufacture the composites where Methyl Ethyl Ketone Peroxide and cobalt Naphthalene were used as coupling agent and accelerator respectively. The thickness of the composite specimen was obtained by laying up layer of fibre and matrix. The untreated composites have been used and mechanical properties are compared with natural fibre and jute fibre composite by using the Ansys method.

  8. Electrodeposition on nanofibrous polymer scaffolds: Rapid mineralization, tunable calcium phosphate composition and topography

    OpenAIRE

    He, Chuanglong; Xiao, Guiyong; Jin, Xiaobing; Sun, Chenghui; Ma, Peter X.

    2010-01-01

    We developed a straightforward, fast, and versatile technique to fabricate mineralized nanofibrous polymer scaffolds for bone regeneration in this work. Nanofibrous poly(l-lactic acid) scaffolds were fabricated using both electrospinning and phase separation techniques. An electrodeposition process was designed to deposit calcium phosphate on the nanofibrous scaffolds. Such scaffolds contain a high quality mineral coating on the fiber surface with tunable surface topography and chemical compo...

  9. Innovative Structural Materials and Sections with Strain Hardening Cementitious Composites

    Science.gov (United States)

    Dey, Vikram

    The motivation of this work is based on development of new construction products with strain hardening cementitious composites (SHCC) geared towards sustainable residential applications. The proposed research has three main objectives: automation of existing manufacturing systems for SHCC laminates; multi-level characterization of mechanical properties of fiber, matrix, interface and composites phases using servo-hydraulic and digital image correlation techniques. Structural behavior of these systems were predicted using ductility based design procedures using classical laminate theory and structural mechanics. SHCC sections are made up of thin sections of matrix with Portland cement based binder and fine aggregates impregnating continuous one-dimensional fibers in individual or bundle form or two/three dimensional woven, bonded or knitted textiles. Traditional fiber reinforced concrete (FRC) use random dispersed chopped fibers in the matrix at a low volume fractions, typically 1-2% to avoid to avoid fiber agglomeration and balling. In conventional FRC, fracture localization occurs immediately after the first crack, resulting in only minor improvement in toughness and tensile strength. However in SHCC systems, distribution of cracking throughout the specimen is facilitated by the fiber bridging mechanism. Influence of material properties of yarn, composition, geometry and weave patterns of textile in the behavior of laminated SHCC skin composites were investigated. Contribution of the cementitious matrix in the early age and long-term performance of laminated composites was studied with supplementary cementitious materials such as fly ash, silica fume, and wollastonite. A closed form model with classical laminate theory and ply discount method, coupled with a damage evolution model was utilized to simulate the non-linear tensile response of these composite materials. A constitutive material model developed earlier in the group was utilized to characterize and

  10. Acid-resistant calcium silicate-based composite implants with high-strength as load-bearing bone graft substitutes and fracture fixation devices.

    Science.gov (United States)

    Wei, Chung-Kai; Ding, Shinn-Jyh

    2016-09-01

    To achieve the excellent mechanical properties of biodegradable materials used for cortical bone graft substitutes and fracture fixation devices remains a challenge. To this end, the biomimetic calcium silicate/gelatin/chitosan oligosaccharide composite implants were developed, with an aim of achieving high strength, controlled degradation, and superior osteogenic activity. The work focused on the effect of gelatin on mechanical properties of the composites under four different kinds of mechanical stresses including compression, tensile, bending, and impact. The evaluation of in vitro degradability and fatigue at two simulated body fluid (SBF) of pH 7.4 and 5.0 was also performed, in which the pH 5.0 condition simulated clinical conditions caused by bacterial induced local metabolic acidosis or tissue inflammation. In addition, human mesenchymal stem cells (hMSCs) were sued to examine osteogenic activity. Experimental results showed that the appropriate amount of gelatin positively contributed to failure enhancement in compressive and impact modes. The 10wt% gelatin-containing composite exhibits the maximum value of the compressive strength (166.1MPa), which is within the reported compressive strength for cortical bone. The stability of the bone implants was apparently affected by the in vitro fatigue, but not by the initial pH environments (7.4 or 5.0). The gelatin not only greatly enhanced the degradation of the composite when soaked in the dynamic SBF solution, but effectively promoted attachment, proliferation, differentiation, and formation of mineralization of hMSCs. The 10wt%-gelatin composite with high initial strength may be a potential implant candidate for cortical bone repair and fracture fixation applications. PMID:27254281

  11. Mishap risk control for advanced aerospace/composite materials

    Science.gov (United States)

    Olson, John M.

    1994-01-01

    Although advanced aerospace materials and advanced composites provide outstanding performance, they also present several unique post-mishap environmental, safety, and health concerns. The purpose of this paper is to provide information on some of the unique hazards and concerns associated with these materials when damaged by fire, explosion, or high-energy impact. Additionally, recommended procedures and precautions are addressed as they pertain to all phases of a composite aircraft mishap response, including fire-fighting, investigation, recovery, clean-up, and guidelines are general in nature and not application-specific. The goal of this project is to provide factual and realistic information which can be used to develop consistent and effective procedures and policies to minimize the potential environmental, safety, and health impacts of a composite aircraft mishap response effort.

  12. Dynamically Driven Phase Transformations in Damaged Composite Materials

    International Nuclear Information System (INIS)

    A model developed for composite materials undergoing dynamicaly driven phase transitions in its constituents has been extended to allow for complex material micro-structure and evolution of damage. In this work, damage is described by interfacial debonding and micro-crack growth. We have applied the analysis to silicon carbide-titanium (SiC-Ti) unidirectional metal matrix composites. In these composites, Ti can undergo a low pressure and temperature solid-solid phase transition. With these extensions we have carried out simulations to study the complex interplay between loading rates, micro-structure, damage, and the thermo-mechanical response of the system as it undergoes a solid-solid phase transitions

  13. Moisture effect on mechanical properties of polymeric composite materials

    Science.gov (United States)

    Airale, A. G.; Carello, M.; Ferraris, A.; Sisca, L.

    2016-05-01

    The influence of moisture on the mechanical properties of fibre-reinforced polymer matrix composites (PMCs) was investigated. Four materials had been take into account considering: both 2×2-Twill woven carbon fibre or glass fibre, thermosetting matrix (Epoxy Resin) or thermoplastic matrix (Polyphenylene Sulfide). The specimens were submitted for 1800 hours to a hygrothermic test to evaluate moisture absorption on the basis of the Fick's law and finally tested to verify the mechanical properties (ultimate tensile strength). The results showed that the absorbed moisture decreases those properties of composites which were dominated by the matrix or the interface, while was not detectable the influence of water on the considered fibre. An important result is that the diffusion coefficient is highest for glass/PPS and lowest for carbon/epoxy composite material. The results give useful suggestions for the design of vehicle components that are exposed to environmental conditions (rain, snow and humidity).

  14. State-of-the-art of biodegradable composite materials

    International Nuclear Information System (INIS)

    Nowadays, the market demand for environment friendly materials is in strong growth. The biodegradable composites (biodegradable fibres and polymers) mainly extracted from renewable resources will be a major contributor to the production of new industrial high performance products partially solving the problem of waste management. At the end of the lifetime, a structural bio-composite could be be crushed and recycled through a controlled industrial composting process. This the state-of-the-art report focuses on the biopolymers the vegetable fibres properties, the mechanisms of biodegradation and the examples of biodegradable composites. Eco-design of new products requires these new materials for which a life cycle analysis is nevertheless necessary to validate their environmental benefits. (authors)

  15. Aluminum-matrix composite materials with shungite rock fillers

    Science.gov (United States)

    Kalashnikov, I. E.; Kovalevski, V. V.; Chernyshova, T. A.; Bolotova, L. K.

    2010-11-01

    A method is proposed for the introduction of shungite rocks into aluminum melts by mechanical mixing with carriers, namely, aluminum granules and reactive titanium powders taking part in exothermic in situ reactions. The structures of composite materials with shungite rock additions are studied, and a stabilizing effect of these additions on dry sliding friction is revealed.

  16. Micromechanically based modelling of thermomechanical properties in composite materials

    International Nuclear Information System (INIS)

    The underlying philosophy and some major computational approaches for micromechanical modelling of inhomogeneous materials are presented. On this basis, concepts for finite element models for use in designed high-performance components made of metal-matrix composites are discussed. (author)

  17. NASA Composite Materials Development: Lessons Learned and Future Challenges

    Science.gov (United States)

    Tenney, Darrel R.; Davis, John G., Jr.; Pipes, R. Byron; Johnston, Norman

    2009-01-01

    Composite materials have emerged as the materials of choice for increasing the performance and reducing the weight and cost of military, general aviation, and transport aircraft and space launch vehicles. Major advancements have been made in the ability to design, fabricate, and analyze large complex aerospace structures. The recent efforts by Boeing and Airbus to incorporate composite into primary load carrying structures of large commercial transports and to certify the airworthiness of these structures is evidence of the significant advancements made in understanding and use of these materials in real world aircraft. NASA has been engaged in research on composites since the late 1960 s and has worked to address many development issues with these materials in an effort to ensure safety, improve performance, and improve affordability of air travel for the public good. This research has ranged from synthesis of advanced resin chemistries to development of mathematical analyses tools to reliably predict the response of built-up structures under combined load conditions. The lessons learned from this research are highlighted with specific examples to illustrate the problems encountered and solutions to these problems. Examples include specific technologies related to environmental effects, processing science, fabrication technologies, nondestructive inspection, damage tolerance, micromechanics, structural mechanics, and residual life prediction. The current state of the technology is reviewed and key issues requiring additional research identified. Also, grand challenges to be solved for expanded use of composites in aero structures are identified.

  18. Shear bond strength of indirect composite material to monolithic zirconia

    Science.gov (United States)

    2016-01-01

    PURPOSE This study aimed to evaluate the effect of surface treatments on bond strength of indirect composite material (Tescera Indirect Composite System) to monolithic zirconia (inCoris TZI). MATERIALS AND METHODS Partially stabilized monolithic zirconia blocks were cut into with 2.0 mm thickness. Sintered zirconia specimens were divided into different surface treatment groups: no treatment (control), sandblasting, glaze layer & hydrofluoric acid application, and sandblasting + glaze layer & hydrofluoric acid application. The indirect composite material was applied to the surface of the monolithic zirconia specimens. Shear bond strength value of each specimen was evaluated after thermocycling. The fractured surface of each specimen was examined with a stereomicroscope and a scanning electron microscope to assess the failure types. The data were analyzed using one-way analysis of variance (ANOVA) and Tukey LSD tests (α=.05). RESULTS Bond strength was significantly lower in untreated specimens than in sandblasted specimens (P<.05). No difference between the glaze layer and hydrofluoric acid application treated groups were observed. However, bond strength for these groups were significantly higher as compared with the other two groups (P<.05). CONCLUSION Combined use of glaze layer & hydrofluoric acid application and silanization are reliable for strong and durable bonding between indirect composite material and monolithic zirconia.

  19. Composite materials derived from geopolymers reinforced by polymer fibers

    Czech Academy of Sciences Publication Activity Database

    Benešová, Lenka

    Novi Sad : Faculty of Technology, University of Novi Sad, 2009 - (Srdic, V.; Ranogajec, J.). s. 78 ISBN 978-86-80995-77-9. [Students Meeting, Processing and Application of Ceramics . 02.12.2009-05.12.2009, Novi Sad] Institutional research plan: CEZ:AV0Z40500505 Keywords : geopolymers * short polymer fibers * composite material Subject RIV: CF - Physical ; Theoretical Chemistry

  20. A comparison of microhardness of indirect composite restorative materials

    DEFF Research Database (Denmark)

    Miranda, Carolina Baptista; Pagani, Clóvis; Bottino, Marco Cícero;

    2003-01-01

    The purpose of this study was to compare the microhardness of four indirect composite resins. Forty cylindrical samples were prepared according to the manufacturer’s recommendations using a Teflon mold. Ten specimens were produced from each tested material, constituting four groups (n=10) as...

  1. How to determine composite material properties using numerical homogenization

    DEFF Research Database (Denmark)

    Andreassen, Erik; Andreasen, Casper Schousboe

    2014-01-01

    Numerical homogenization is an efficient way to determine effective macroscopic properties, such as the elasticity tensor, of a periodic composite material. In this paper an educational description of the method is provided based on a short, self-contained Matlab implementation. It is shown how the...

  2. Study on the Compatibility of SMA and Composite Materials by Holographic Interferometry

    Institute of Scientific and Technical Information of China (English)

    ZHAO Zhimin

    2000-01-01

    With the help of holographic interferometry a study is conducted on the compatibility of SMA (shape memory alloy) and epoxy resin composite material. The paper gives experiment results and analysis which show that after coupling SMA with the composite material, the flexural rigidity of composite material is somewhat reinforced. Under certain conditions, SMA and the epoxy resin composite material are compatible.

  3. Properties of composite materials used for bracket bonding.

    Science.gov (United States)

    Gama, Ana Caroline Silva; Moraes, André Guaraci de Vito; Yamasaki, Lilyan Cardoso; Loguercio, Alessandro Dourado; Carvalho, Ceci Nunes; Bauer, José

    2013-01-01

    The purpose of this study was to evaluate in vitro the shear bond strength to enamel, flexural strength, flexural modulus, and contraction stress of one orthodontic composite and two flowable composites. Orthodontic brackets were bonded to 45 human maxillary premolars with the composites Transbond XT, Filtek Z-350 flow and Opallis flow and tested for shear bond strength. For measurement of flexural strength and flexural modulus, specimens were fabricated and tested under flexion. For the contraction stress test, cylindrical specimens were tested and an extensometer determined the height of the specimens. The data were subjected to one-way ANOVA and Tukey's test (α=0.05). The shear bond strength values were significantly lower (p0.05) while the flexural modulus was significantly higher (p<0.05) for Transbond XT than for Filtek Z-350 flow and Opallis flow. The orthodontic composite presented significantly lower contraction stress values than the flowable composites (p<0.05). The light-activated orthodontic composite material presented higher flexural modulus and shear bond strength and lower contraction stress than both flowable composites. PMID:23969920

  4. Enhanced laminated composite phase change material for energy storage

    International Nuclear Information System (INIS)

    This paper summarises studies undertaken towards the development of a laminated composite aluminium/hexadecane phase change material (PCM) drywall based on previous analytical work. The study also covered the selection and testing of various types of adhesive materials and identified Polyvinyl acetate (PVA) material as a suitable bonding material. For the purpose of comparison pure hexadecane and composite aluminium/hexadecane samples were developed and tested. The test results revealed faster thermal response by the aluminium/hexadecane sample regarding the rate of heat flux and also achieved about 10% and 15% heat transfer enhancements during the charging and discharging periods respectively. Its measured effective thermal conductivity also increased remarkably to 1.25 W/mK as compared with 0.15 W/mK for pure hexadecane. However there was about 5% less total cumulative thermal energy discharged at the end of the test which indicates that its effective thermal capacity was reduced by the presence of the aluminium particles. The study has shown that some of the scientific and technical barriers associated with the development of laminated composite PCM drywall systems can be overcome but further investigations of effects of adhesive materials are needed.

  5. Toward Uniformly Dispersed Battery Electrode Composite Materials: Characteristics and Performance.

    Science.gov (United States)

    Kwon, Yo Han; Huie, Matthew M; Choi, Dalsu; Chang, Mincheol; Marschilok, Amy C; Takeuchi, Kenneth J; Takeuchi, Esther S; Reichmanis, Elsa

    2016-02-10

    Battery electrodes are complex mesoscale systems comprised of electroactive components, conductive additives, and binders. In this report, methods for processing electrodes with dispersion of the components are described. To investigate the degree of material dispersion, a spin-coating technique was adopted to provide a thin, uniform layer that enabled observation of the morphology. Distinct differences in the distribution profile of the electrode components arising from individual materials physical affinities were readily identified. Hansen solubility parameter (HSP) analysis revealed pertinent surface interactions associated with materials dispersivity. Further studies demonstrated that HSPs can provide an effective strategy to identify surface modification approaches for improved dispersions of battery electrode materials. Specifically, introduction of surfactantlike functionality such as oleic acid (OA) capping and P3HT-conjugated polymer wrapping on the surface of nanomaterials significantly enhanced material dispersity over the composite electrode. The approach to the surface treatment on the basis of HSP study can facilitate design of composite electrodes with uniformly dispersed morphology and may contribute to enhancing their electrical and electrochemical behaviors. The conductivity of the composites and their electrochemical performance was also characterized. The study illustrates the importance of considering electronic conductivity, electron transfer, and ion transport in the design of environments incorporating active nanomaterials. PMID:26765041

  6. Fabrication of microscale materials with programmable composition gradients.

    Science.gov (United States)

    Laval, Cédric; Bouchaudy, Anne; Salmon, Jean-Baptiste

    2016-04-01

    We present an original microfluidic technique coupling pervaporation and the use of Quake valves to fabricate microscale materials (∼10 × 100 μm(2) × 1 cm) with composition gradients along their longest dimension. Our device exploits pervaporation of water through a thin poly(dimethylsiloxane) (PDMS) membrane to continuously pump solutions (or dispersions) contained in different reservoirs connected to a microfluidic channel. This pervaporation-induced flow concentrates solutes (or particles) at the tip of the channel up to the formation of a dense material. The latter invades the channel as it is constantly enriched by an incoming flux of solutes/particles. Upstream Quake valves are used to select which reservoir is connected to the pervaporation channel and thus which solution (or dispersion) enriches the material during its growth. The microfluidic configuration of the pervaporation process is used to impose controlled growth along the channel thus enabling one to program spatial composition gradients using appropriate actuations of the valves. We demonstrate the possibilities offered by our technique through the fabrication of dense assemblies of nanoparticles and polymer composites with programmed gradients of fluorescent dyes. We also address the key issue of the spatial resolution of our gradients and we show that well-defined spatial modulations down to ≈50 μm can be obtained within colloidal materials, whereas gradients within polymer materials are resolved on length scales down to ≈1 mm due to molecular diffusion. PMID:26931112

  7. Evaluations of composition for buffer materials based on genetic algorithms

    International Nuclear Information System (INIS)

    To provide an overall functional evaluations of buffer materials, this study attempted to investigate the relationships among the engineering properties, plastic index (PI), compaction efficiency, hydraulic conductivity(k); sorption properties, distribution ratio(Rd) for some buffer materials composed of quartz sand and bentonite. According to engineering and sorption properties, the optimal composition can be found out with some optimal approaches. However, a genetic algorithm (GA) is a robust method for searching the optimum solution to a complex problem and widely is applied to many different topics. It is a search algorithm based upon mechanics of natural selection, derived from the theory of natural evolution. The study of genetic algorithms (GAS) has developed into powerful optimization approach since 1970, so this study tries to apply GAS to this problem. Under both synthetic groundwater (GW) and seawater (SW) conditions, the composition of quartz sand and bentonite was evaluated by associating engineering and sorption properties. Due to ends of experiments, this study assumes linearly proportional relationship among bentonite content of buffer materials, PI, k, and sorption properties. And GAS was carried out using a population size of 50, a crossover rate of 0,5, and a mutation rate of 0,1. The final results based on genetic algorithms are consistent with consequences of previous tests. From the viewpoints of associated engineering and sorption properties, the buffer materials nearly containing 70% bentonite are probably the most favorable choice. These results will show a determination of more effective buffer material composition. (authors)

  8. Preliminary study of raw material for calcium silicate/PVA coating on Ti-6Al-4V alloy

    International Nuclear Information System (INIS)

    Calcium silicate bioceramic was prepared from the rice husk and limestone resources using the sol gel method. The preparations of CaSiO3 formulation were differ from the previous study due CaO/SiO2 amount with 45:55 ratio. X-Ray Fluorescence analysis was carried out to clarify the amount of SiO2 and CaO content in the limestone and rice husk ash. The high amount of CaO was found in the limestone with the percentages of 97.22%, whereby 89% of SiO2 content of the rice husk ash. Several milling time were studied to obtain the optimized milling ti me and speed in progress to obtain nano size particle. The particle size analysis result confirms that increase in milling time does not certainly reduce the size of particle. The addition of 0.05% polyvinyl alcohol as a binder did not change the phases or composition of calcium silicates after examined by X-Ray diffraction analysis which make it suitable to be used as a binder for calcium silicate coating without changing the chemical structure

  9. Preliminary study of raw material for calcium silicate/PVA coating on Ti-6Al-4V alloy

    Energy Technology Data Exchange (ETDEWEB)

    Azam, Farah ' Atiqah bt Abdul; Shamsudin, Roslinda, E-mail: linda@ukm.edu.my [School of Applied Physics, Faculty of Science and Technology Universiti Kebangsaan Malaysia, 43600 UKM Bangi, Selangor Darul Ehsan (Malaysia)

    2015-09-25

    Calcium silicate bioceramic was prepared from the rice husk and limestone resources using the sol gel method. The preparations of CaSiO{sub 3} formulation were differ from the previous study due CaO/SiO{sub 2} amount with 45:55 ratio. X-Ray Fluorescence analysis was carried out to clarify the amount of SiO{sub 2} and CaO content in the limestone and rice husk ash. The high amount of CaO was found in the limestone with the percentages of 97.22%, whereby 89% of SiO{sub 2} content of the rice husk ash. Several milling time were studied to obtain the optimized milling ti me and speed in progress to obtain nano size particle. The particle size analysis result confirms that increase in milling time does not certainly reduce the size of particle. The addition of 0.05% polyvinyl alcohol as a binder did not change the phases or composition of calcium silicates after examined by X-Ray diffraction analysis which make it suitable to be used as a binder for calcium silicate coating without changing the chemical structure.

  10. Preliminary study of raw material for calcium silicate/PVA coating on Ti-6Al-4V alloy

    Science.gov (United States)

    Azam, Farah Atiqah bt Abdul; Shamsudin, Roslinda

    2015-09-01

    Calcium silicate bioceramic was prepared from the rice husk and limestone resources using the sol gel method. The preparations of CaSiO3 formulation were differ from the previous study due CaO/SiO2 amount with 45:55 ratio. X-Ray Fluorescence analysis was carried out to clarify the amount of SiO2 and CaO content in the limestone and rice husk ash. The high amount of CaO was found in the limestone with the percentages of 97.22%, whereby 89% of SiO2 content of the rice husk ash. Several milling time were studied to obtain the optimized milling ti me and speed in progress to obtain nano size particle. The particle size analysis result confirms that increase in milling time does not certainly reduce the size of particle. The addition of 0.05% polyvinyl alcohol as a binder did not change the phases or composition of calcium silicates after examined by X-Ray diffraction analysis which make it suitable to be used as a binder for calcium silicate coating without changing the chemical structure.

  11. Recent developments of discrete material optimization of laminated composite structures

    DEFF Research Database (Denmark)

    Lund, Erik; Sørensen, Rene

    2015-01-01

    This work will give a quick summary of recent developments of the Discrete Material Optimization approach for structural optimization of laminated composite structures. This approach can be seen as a multi-material topology optimization approach for selecting the best ply material and number of...... plies in a laminated composite structure. The conceptual combinatorial design problem is relaxed to a continuous problem such that well-established gradient based optimization techniques can be applied, and the optimization problem is solved on basis of interpolation schemes with penalization. The...... it possible also to include local criteria such as strength criteria in the formulations. This is illustrated by structural optimization of a corner hinged laminated plate in this paper, and at ICCM20 it will also be demonstrated for optimization of a main spar from a wind turbine blade....

  12. Strengthening of building structures using carbon composite materials

    Directory of Open Access Journals (Sweden)

    N.V. Paranicheva

    2010-03-01

    Full Text Available Currently, the question of ensuring the reliability of various building structures both at the stage of their construction and during operation is very urgent. There are a lot of different ways and constructive methods of structures strengthening. Аt the same time, traditional ways of concrete structures strengthening with steel reinforcement are such expensive, time consuming and in some cases require to interrupt the building operation. As an alternative, it is proposed to use composite materials based on high-strength carbon fibers.The authors consider the properties, advantages, disadvantages and the methods of application of these materials. This article presents results of a technical survey carried out in a public building in 2009. In this building the CFRP was used to strengthen concrete slabs, resting on the crossbar consoles. The calculation of the strength is adduced and the section selection is made. The authors demonstrate their conclusions about the feasibility of using carbon composite materials.

  13. Chemical composition of material fractions in Danish household waste

    DEFF Research Database (Denmark)

    Riber, Christian; Petersen, Claus; Christensen, Thomas Højlund

    2009-01-01

    The chemical composition of Danish household waste was determined by two approaches: a direct method where the chemical composition (61 substances) of 48 material fractions was determined after hand sorting of about 20 tonnes of waste collected from 2200 households; and an indirect method where...... batches of 80-1200 tonnes of unsorted household waste was incinerated and the content of the waste determined from the content of the outputs from the incinerator. The indirect method is believed to better represent the small but highly contaminated material fractions (e,g., batteries) than the direct...... method, because of the larger quantities included and the more homogenous material to sample from. Differences between the direct and the direct methods led to corrections in the of heavy metal concentration of a few fractions. The majority of the energy content of the waste originates from organic waste...

  14. Dual-nanoparticulate-reinforced aluminum matrix composite materials

    Science.gov (United States)

    Kwon, Hansang; Cho, Seungchan; Leparoux, Marc; Kawasaki, Akira

    2012-06-01

    Aluminum (Al) matrix composite materials reinforced with carbon nanotubes (CNT) and silicon carbide nanoparticles (nano-SiC) were fabricated by mechanical ball milling, followed by hot-pressing. Nano-SiC was used as an active mixing agent for dispersing the CNTs in the Al powder. The hardness of the produced composites was dramatically increased, up to eight times higher than bulk pure Al, by increasing the amount of nano-SiC particles. A small quantity of aluminum carbide (Al4C3) was observed by TEM analysis and quantified using x-ray diffraction. The composite with the highest hardness values contained some nanosized Al4C3. Along with the CNT and the nano-SiC, Al4C3 also seemed to play a role in the enhanced hardness of the composites. The high energy milling process seems to lead to a homogeneous dispersion of the high aspect ratio CNTs, and of the nearly spherical nano-SiC particles in the Al matrix. This powder metallurgical approach could also be applied to other nanoreinforced composites, such as ceramics or complex matrix materials.

  15. VAMAS tests of structural materials on aluminum alloy and composite material at cryogenic temperatures

    Energy Technology Data Exchange (ETDEWEB)

    Ogata, T. [National Research Institute for Metals, Tsukuba, Ibaraki (Japan); Evans, D. [Rutherford Appleton Lab., Chilton (United Kingdom)

    1997-06-01

    A Technical Working Area 17, cryogenic structural materials, has been organized in the Versailles Project on Advanced Materials and Standards (VAMAS) to promote the prestandardization program on material properties tests of glass fiber reinforced polymer (GFRP) composite materials and alloys at liquid helium temperature. A series of international interlaboratory comparisons of both tensile and fracture toughness tests for aluminum alloy 2219 and compression and shear tests for composite material G-10CR were performed. Nine research institutes from seven nations have participated in this project. The results prove that there are few problems in cryogenic tensile tests for alloy materials. In compression and shear tests, the amount of data scatter was identified and further experiments are planned. This paper presents the program details and interim results of round robin tests.

  16. VAMAS tests of structural materials on aluminum alloy and composite material at cryogenic temperatures

    International Nuclear Information System (INIS)

    A Technical Working Area 17, cryogenic structural materials, has been organized in the Versailles Project on Advanced Materials and Standards (VAMAS) to promote the prestandardization program on material properties tests of glass fiber reinforced polymer (GFRP) composite materials and alloys at liquid helium temperature. A series of international interlaboratory comparisons of both tensile and fracture toughness tests for aluminum alloy 2219 and compression and shear tests for composite material G-10CR were performed. Nine research institutes from seven nations have participated in this project. The results prove that there are few problems in cryogenic tensile tests for alloy materials. In compression and shear tests, the amount of data scatter was identified and further experiments are planned. This paper presents the program details and interim results of round robin tests

  17. Fiber reinforced composite material and method of manufacturing the same

    International Nuclear Information System (INIS)

    A mother material resin is impregnated to a base material comprising an assembly of continuous fibers, and then the mother material resin is cured. The mother material resin contains a main agent comprising diglycidylether of bisphenol A alone or together with tetrafunctional-type epoxy resin. The mother resin further contains a curing agent comprising diaminodiphenylmethane alone or a mixture thereof with methaphenylene diamine, and a reactive diluent for an epoxy resin. The continuous fibers are preferably comprise glass fibers, carbon fibers or aromatic polyamidetype fibers. As the tetrafunctional-type epoxy resin, tetraglycidylamino-diphenyl methane is preferable. As the reactive diluent for epoxy resin, a styrene oxide, glycidylmethacrylate or the like is preferable. Thus, a composite material capable of keeping high strength at a circumstance to be exposed to radiation rays can be obtained. (I.N.)

  18. Test Report: Direct and Indirect Lightning Effects on Composite Materials

    Science.gov (United States)

    Evans, R. W.

    1997-01-01

    Lightning tests were performed on composite materials as a part of an investigation of electromagnetic effects on the materials. Samples were subjected to direct and remote simulated lightning strikes. Samples included various thicknesses of graphite filament reinforced plastic (GFRP), material enhanced by expanded aluminum foil layers, and material with an aluminum honeycomb core. Shielding properties of the material and damage to the sample surfaces and joints were investigated. Adding expanded aluminum foil layers and increasing the thickness of GFRP improves the shielding effectiveness against lightning induced fields and the ability to withstand lightning strikes. A report describing the lightning strike tests performed by the U.S. Army Redstone Technical Test Center, Redstone Arsenal, AL, STERT-TE-E-EM, is included as an appendix.

  19. Evaluation of Targeting Systems Composite Materials - Sterilization Decomposition

    Czech Academy of Sciences Publication Activity Database

    Suchý, Tomáš; Sedláček, R.; Sucharda, Zbyněk; Balík, Karel; Sochor, M.

    Dublin : National University of Ireland , 2011, s. 733. [European Conference on Biomaterials /24./. Dublin (IE), 04.09.2011-08.09.2011] R&D Projects: GA ČR(CZ) GAP108/10/1457 Institutional research plan: CEZ:AV0Z30460519 Keywords : composite * biomechanics * surgery Subject RIV: JI - Composite Materials https://docs.google.com/leaf?id=0BxqLUkEGCLpvN2E3MzkwZDItY2QyMy00MGI5LW%20IyZjYtOWZlYzExMDExYTZk&hl=en_US

  20. A generalized methodology to characterize composite materials for pyrolysis models

    Science.gov (United States)

    McKinnon, Mark B.

    The predictive capabilities of computational fire models have improved in recent years such that models have become an integral part of many research efforts. Models improve the understanding of the fire risk of materials and may decrease the number of expensive experiments required to assess the fire hazard of a specific material or designed space. A critical component of a predictive fire model is the pyrolysis sub-model that provides a mathematical representation of the rate of gaseous fuel production from condensed phase fuels given a heat flux incident to the material surface. The modern, comprehensive pyrolysis sub-models that are common today require the definition of many model parameters to accurately represent the physical description of materials that are ubiquitous in the built environment. Coupled with the increase in the number of parameters required to accurately represent the pyrolysis of materials is the increasing prevalence in the built environment of engineered composite materials that have never been measured or modeled. The motivation behind this project is to develop a systematic, generalized methodology to determine the requisite parameters to generate pyrolysis models with predictive capabilities for layered composite materials that are common in industrial and commercial applications. This methodology has been applied to four common composites in this work that exhibit a range of material structures and component materials. The methodology utilizes a multi-scale experimental approach in which each test is designed to isolate and determine a specific subset of the parameters required to define a material in the model. Data collected in simultaneous thermogravimetry and differential scanning calorimetry experiments were analyzed to determine the reaction kinetics, thermodynamic properties, and energetics of decomposition for each component of the composite. Data collected in microscale combustion calorimetry experiments were analyzed to

  1. The Influence of Calcium Chloride Salt Solution on the Transport Properties of Cementitious Materials

    Directory of Open Access Journals (Sweden)

    Yaghoob Farnam

    2015-01-01

    Full Text Available The chemical interaction between calcium chloride (CaCl2 and cementitious binder may alter the transport properties of concrete which are important in predicting the service life of infrastructure elements. This paper presents a series of fluid and gas transport measurements made on cementitious mortars before and after exposure to various solutions with concentrations ranging from 0% to 29.8% CaCl2 by mass. Fluid absorption, oxygen diffusivity, and oxygen permeability were measured on mortar samples prepared using Type I and Type V cements. Three primary factors influence the transport properties of mortar exposed to CaCl2: (1 changes in the degree of saturation, (2 calcium hydroxide leaching, and (3 formation of chemical reaction products (i.e., Friedel’s salt, Kuzel’s salt, and calcium oxychloride. It is shown that an increase in the degree of saturation decreases oxygen permeability. At lower concentrations (~12%, the formation of chemical reaction products (mainly calcium oxychloride is a dominant factor decreasing the fluid and gas transport in concrete.

  2. Microstructure of composite material with powders of barium ferrite

    Directory of Open Access Journals (Sweden)

    R. Nowosielski

    2006-04-01

    Full Text Available Purpose: The aim of the present work is the microstructure characterization of commercial powder BaFe12O19 (as-prepared and composite material with BaFe12O19 powders and polymer matrix, using XRD (X-Ray Diffraction and SEM (Scanning Electron Microscopy methods.Design/methodology/approach: The morphology of barium ferrite powders and a fracture surface of the examined composite material was realized by using the scanning electron microscope. The methods of X-ray diffraction were used for the qualitative phase analysis. The parameters of diffraction line profiles were determined by PRO-FIT Toraya procedure.Findings: The X-ray diffraction analysis permitted on identification the BaFe12O19 and Fe2O3 phases in an examined material. Basing on Toraya method is determination of: lattice parameters, crystallite size (D and the lattice distortion (. Distribution of powders of barium ferrite in polymer matrix is irregular and powder particles have irregular shapes and dimensions.Research limitations/implications: For future research the X-ray analysis should be performed by the Rietveld method, which allows to characterization the microstructure of tested material and verification of its qualitative phase composition.Originality/value: The applied Toraya method of structure analysis appeared to be very useful in the microstructure analysis.

  3. Single-walled carbon nanotube networks in conductive composite materials.

    Science.gov (United States)

    Bârsan, Oana A; Hoffmann, Günter G; van der Ven, Leo G J; de With, G Bert

    2014-01-01

    Electrically conductive composite materials can be used for a wide range of applications because they combine the advantages of a specific polymeric material (e.g., thermal and mechanical properties) with the electrical properties of conductive filler particles. However, the overall electrical behaviour of these composite materials is usually much below the potential of the conductive fillers, mainly because by mixing two different components, new interfaces and interphases are created, changing the properties and behaviours of both. Our goal is to characterize and understand the nature and influence of these interfaces on the electrical properties of composite materials. We have improved a technique based on the use of sodium carboxymethyl cellulose (CMC) to disperse single-walled carbon nanotubes (SWCNTs) in water, followed by coating glass substrates, and drying and removing the CMC with a nitric acid treatment. We used electron microscopy and atomic force microscopy techniques to characterize the SWCNT films, and developed an in situ resistance measurement technique to analyse the influence of both the individual components and the mixture of an epoxy/amine system on the electrical behaviour of the SWCNTs. The results showed that impregnating a SWCNT network with a polymer is not the only factor that affects the film resistance; air exposure, temperature, physical and chemical properties of the individual polymer components, and also the formation of a polymeric network, can all have an influence on the macroscopic electrical properties of the initial SWCNT network. These results emphasize the importance of understanding the effects that each of the components can have on each other before trying to prepare an efficient polymer composite material. PMID:25430670

  4. Fibronectin-calcium phosphate composite layer on hydroxyapatite to enhance adhesion, cell spread and osteogenic differentiation of human mesenchymal stem cells in vitro

    International Nuclear Information System (INIS)

    Fibronectin (Fn) and type I collagen (Col) were immobilized on a surface of a hydroxyapatite (HAP) ceramic by coprecipitation with calcium phosphate in a supersaturated calcium phosphate solution prepared by mixing clinically approved infusion fluids. These proteins and the calcium phosphate precipitate formed a composite surface layer. As a result, the proteins were immobilized firmly as not to be released completely for 3 d in a physiological salt solution. When human mesenchymal stem cells (hMSCs) were cultured on a HAP ceramic in a differentiation medium supplemented with dexamethasone, β-glycerophosphate and ascorbic acid, hMSCs spread well within 1 h. The alkaline phosphatase (ALP) activity of hMSCs cultured on the Fn-calcium phosphate composite layer significantly increased compared with that of hMSCs cultured on the untreated HAP ceramic. On the other hand, Col did not increase the ALP activity of hMSCs and no synergy between Fn and Col was observed. Therefore, the Fn-calcium phosphate composite layer formed on the HAP is useful for the enhancement of the spreading and osteogenic differentiation of hMSCs in vitro

  5. Fibronectin-calcium phosphate composite layer on hydroxyapatite to enhance adhesion, cell spread and osteogenic differentiation of human mesenchymal stem cells in vitro

    Energy Technology Data Exchange (ETDEWEB)

    Sogo, Yu [National Institute of Advanced Industrial Science and Technology (AIST), Institute for Human Science and Biomedical Engineering, Central 6, 1-1-1, Higashi, Tsukuba, Ibaraki 305-8566 (Japan); Ito, Atsuo [National Institute of Advanced Industrial Science and Technology (AIST), Institute for Human Science and Biomedical Engineering, Central 6, 1-1-1, Higashi, Tsukuba, Ibaraki 305-8566 (Japan); Matsuno, Tomonori [Department of Oral and Maxillofacial Surgery, School of Life Dentistry at Tokyo, Nippon Dental University, 1-9-20 Fujimi, Chiyoda-ku, Tokyo 102-8159 (Japan); Oyane, Ayako [National Institute of Advanced Industrial Science and Technology (AIST), Nanotechnology Research Institute, Central 4, 1-1-1 Higashi, Tsukuba, Ibaraki 305-8562 (Japan); Tamazawa, Gaku [Department of Oral and Maxillofacial Surgery, School of Life Dentistry at Tokyo, Nippon Dental University, 1-9-20 Fujimi, Chiyoda-ku, Tokyo 102-8159 (Japan); Satoh, Tazuko [Department of Oral and Maxillofacial Surgery, School of Life Dentistry at Tokyo, Nippon Dental University, 1-9-20 Fujimi, Chiyoda-ku, Tokyo 102-8159 (Japan); Yamazaki, Atsushi [Department of Resources and Environmental Engineering, School of Science and Engineering, Waseda University, 3-4-1 Okubo, Shinjuku-ku, Tokyo 169-8555 (Japan); Uchimura, Eiji [Department of Resources and Environmental Engineering, School of Science and Engineering, Waseda University, 3-4-1 Okubo, Shinjuku-ku, Tokyo 169-8555 (Japan); Ohno, Tadao [Department of Resources and Environmental Engineering, School of Science and Engineering, Waseda University, 3-4-1 Okubo, Shinjuku-ku, Tokyo 169-8555 (Japan)

    2007-06-01

    Fibronectin (Fn) and type I collagen (Col) were immobilized on a surface of a hydroxyapatite (HAP) ceramic by coprecipitation with calcium phosphate in a supersaturated calcium phosphate solution prepared by mixing clinically approved infusion fluids. These proteins and the calcium phosphate precipitate formed a composite surface layer. As a result, the proteins were immobilized firmly as not to be released completely for 3 d in a physiological salt solution. When human mesenchymal stem cells (hMSCs) were cultured on a HAP ceramic in a differentiation medium supplemented with dexamethasone, {beta}-glycerophosphate and ascorbic acid, hMSCs spread well within 1 h. The alkaline phosphatase (ALP) activity of hMSCs cultured on the Fn-calcium phosphate composite layer significantly increased compared with that of hMSCs cultured on the untreated HAP ceramic. On the other hand, Col did not increase the ALP activity of hMSCs and no synergy between Fn and Col was observed. Therefore, the Fn-calcium phosphate composite layer formed on the HAP is useful for the enhancement of the spreading and osteogenic differentiation of hMSCs in vitro.

  6. Analysis of changes in selected parameters of calcium and magnesium metabolism in response to diet composition and B-group vitamin supplementation in rat

    OpenAIRE

    Joanna Sadowska

    2010-01-01

    Background. The aim of the study was to investigate the effects of a diet modification and supplementation with B-group vitamins, on selected characteristics of calcium and magnesium management in rats. Material and methods. The experiment was carried out on 60 rats aged 5 months. Animals were fed two different diets. Groups I and II received clean tap water to drink, while group III had water solution of group-B vitamins. Results. Analysis of blood plasma calcium and magnesiu...

  7. Compendium of Material Composition Data for Radiation Transport Modeling

    Energy Technology Data Exchange (ETDEWEB)

    McConn, Ronald J.; Gesh, Christopher J.; Pagh, Richard T.; Rucker, Robert A.; Williams III, Robert

    2011-03-04

    Introduction Meaningful simulations of radiation transport applications require realistic definitions of material composition and densities. When seeking that information for applications in fields such as homeland security, radiation shielding and protection, and criticality safety, researchers usually encounter a variety of materials for which elemental compositions are not readily available or densities are not defined. Publication of the Compendium of Material Composition Data for Radiation Transport Modeling, Revision 0, in 2006 was the first step toward mitigating this problem. Revision 0 of this document listed 121 materials, selected mostly from the combined personal libraries of staff at the Pacific Northwest National Laboratory (PNNL), and thus had a scope that was recognized at the time to be limited. Nevertheless, its creation did provide a well-referenced source of some unique or hard-to-define material data in a format that could be used directly in radiation transport calculations being performed at PNNL. Moreover, having a single common set of material definitions also helped to standardize at least one aspect of the various modeling efforts across the laboratory by providing separate researchers the ability to compare different model results using a common basis of materials. The authors of the 2006 compendium understood that, depending on its use and feedback, the compendium would need to be revised to correct errors or inconsistencies in the data for the original 121 materials, as well as to increase (per users suggestions) the number of materials listed. This 2010 revision of the compendium has accomplished both of those objectives. The most obvious change is the increased number of materials from 121 to 372. The not-so-obvious change is the mechanism used to produce the data listed here. The data listed in the 2006 document were compiled, evaluated, entered, and error-checked by a group of individuals essentially by hand, providing no library

  8. Preparation of poly (methyl methacrylate)/nanometer calcium carbonate composite by in-situ emulsion polymerization

    Institute of Scientific and Technical Information of China (English)

    史建明; 包永忠; 黄志明; 翁志学

    2004-01-01

    Methyl methacrylate (MMA) emulsion polymerization in the presence of nanometer calcium carbonate(nano-CaCO3) surface modified with γ-methacryloxypropyltrimethoxysilane (MPTMS) was carried out to prepare poly (methyl methacrylate) (PMMA)/nano-CaCO3 composite. The reaction between nano-CaCO3 and MPTMS, and the grafting of PMMA onto nano-CaCO3 were confirmed by infrared spectrum. The grafting ratio and grafting efficiency of PMMA on nano-CaCO3 modified with MPTMS were much higher than that on nano-CaCO3 modified with stearic acid. The grafting ratio of PMMA increased as the weight ratio between MMA and nano-CaCO3 increased, while the grafting efficiency of PMMA decreased. Transmission electron micrograph showed that nano-CaCO3 covered with PMMA was formed by in-situ emulsion polymerization.

  9. Data for accelerated degradation of calcium phosphate surface-coated polycaprolactone and polycaprolactone/bioactive glass composite scaffolds.

    Science.gov (United States)

    Poh, Patrina S P; Hutmacher, Dietmar W; Holzapfel, Boris M; Solanki, Anu K; Woodruff, Maria A

    2016-06-01

    Polycaprolactone (PCL)-based composite scaffolds containing 50 wt% of 45S5 bioactive glass (45S5) or strontium-substituted bioactive glass (SrBG) particles were fabricated into scaffolds using melt-extrusion based additive manufacturing technique. Additionally, the PCL scaffolds were surface coated with a layer of calcium phosphate (CaP). For a comparison of the scaffold degradation, the scaffolds were then subjected to in vitro accelerated degradation by immersion in 5 M sodium hydroxide (NaOH) solution for up to 7 days. The scaffold׳s morphology was observed by means of SEM imaging and scaffold mass loss was recorded over the experimental period. PMID:27081669

  10. Wetting, superhydrophobicity, and icephobicity in biomimetic composite materials

    Science.gov (United States)

    Hejazi, Vahid

    Recent developments in nano- and bio-technology require new materials. Among these new classes of materials which have emerged in the recent years are biomimetic materials, which mimic structure and properties of materials found in living nature. There are a large number of biological objects including bacteria, animals and plants with properties of interest for engineers. Among these properties is the ability of the lotus leaf and other natural materials to repel water, which has inspired researchers to prepare similar surfaces. The Lotus effect involving roughness-induced superhydrophobicity is a way to design nonwetting, self-cleaning, omniphobic, icephobic, and antifouling surfaces. The range of actual and potential applications of superhydrophobic surfaces is diverse including optical, building and architecture, textiles, solar panels, lab-on-a-chip, microfluidic devices, and applications requiring antifouling from biological and organic contaminants. In this thesis, in chapter one, we introduce the general concepts and definitions regarding the wetting properties of the surfaces. In chapter two, we develop novel models and conduct experiments on wetting of composite materials. To design sustainable superhydrophobic metal matrix composite (MMC) surfaces, we suggest using hydrophobic reinforcement in the bulk of the material, rather than only at its surface. We experimentally study the wetting properties of graphite-reinforced Al- and Cu-based composites and conclude that the Cu-based MMCs have the potential to be used in the future for the applications where the wear-resistant superhydrophobicity is required. In chapter three, we introduce hydrophobic coating at the surface of concrete materials making them waterproof to prevent material failure, because concretes and ceramics cannot stop water from seeping through them and forming cracks. We create water-repellant concretes with CA close to 160o using superhydrophobic coating. In chapter four, experimental

  11. New toughening concepts for ceramic composites from rigid natural materials.

    Science.gov (United States)

    Mayer, George

    2011-07-01

    The mechanisms underlying the toughening in rigid natural composites exhibited by the concentric cylindrical composites of spicules of hexactinellid sponges, and by the nacre (brick-and-mortar) structure of mollusks such as Haliotis rufescens (red abalone), as well as the crossed-lamellar structure of Strombus gigas (queen conch) show commonalities in the manner in which toughening takes place. It is proposed that crack diversion, a new kind of crack bridging, resulting in retardation of delamination, creation of new surface areas, and other energy-dissipating mechanisms occur in both natural systems. However, these are generally different from the toughening mechanisms that are utilized for other classes of structural materials. Complementary to those mechanisms found in rigid natural ceramic/organic composites, special architectures and thin viscoelastic organic layers have been found to play controlling roles in energy dissipation in these structures. PMID:21565715

  12. The influence of milk composition on pH and calcium activity measured in situ during heat treatment of reconstituted skim milk.

    Science.gov (United States)

    Chandrapala, Jayani; McKinnon, Ian; Augustin, Mary Ann; Udabage, Punsandani

    2010-08-01

    The pH and calcium activity of reconstituted skim milk solutions (9-21% w/w milk solids non-fat) on heating and after cooling were studied as a function of milk pH prior to heating (pH 6.2-7.2 at 25 degrees C) and added calcium complexing agents (phosphate or EDTA). The pH decreased as the temperature was raised from 25 to 90 degrees C and the magnitude of the pH decrease was greater with increase in initial pH at 25 degrees C before heating or milk concentration. The pH decrease on heating from 25 to 90 degrees C in skim milk solutions with added calcium complexing agents was lower than that of milk without the addition of these salts. The calcium activity decreased on heating from 25 to 60 degrees C. The magnitude of the change decreased with increase in initial pH at 25 degrees C before heating and milk concentration. The decrease in calcium activity on heating from 25 to 60 degrees C for skim milk solutions with added calcium complexing agents was lower than that of milk solutions without the addition of calcium complexing agents. The changes in pH and calcium activity on heating milk were largely reversible after cooling the milk. The results suggested that the pH and calcium activity at high temperatures are a function of the milk composition. Knowledge of the initial pH prior to heating alone is not sufficient for predicting the changes that occur during heating. PMID:20196897

  13. Whisker-reinforced bioactive composites containing calcium phosphate cement fillers: effects of filler ratio and surface treatments on mechanical properties.

    Science.gov (United States)

    Xu, H H; Quinn, J B

    2001-11-01

    Calcium phosphate cement (CPC) sets to form microporous solid hydroxyapatite with excellent osteoconductivity, but its brittleness and low strength prohibit use in stress-bearing locations. The aim of this study was to incorporate prehardened CPC particles and ceramic whiskers in a resin matrix to improve the strength and fracture resistance, and to investigate the effects of key microstructural variables on composite mechanical properties. Two types of whiskers were used: silicon nitride, and silicon carbide. The whiskers were surface-treated by fusing with silica and by silanization. The CPC particle fillers were either silanized or not silanized. Seven mass ratios of whisker-silica/CPC were mixed: 0:1 (no whisker-silica), 1:5, 1:2, 1:1, 2:1, 5:1, and 1:0 (no CPC). Each powder was blended with a bisphenol-a-glycidyl methacrylate-based resin to harden in 2 x 2 x 25 mm molds by two-part chemical curing. The specimens were tested in three-point flexure to measure strength, work-of-fracture (toughness), and elastic modulus. Two-way analysis of variance was used to analyze the data, and scanning electron microscopy was used to examine specimen fracture surfaces. The whisker-silica/CPC ratio had significant effects on composite properties (p particles without whiskers. The composite properties were determined by whisker-to-CPC ratio and filler surface treatments. PMID:11484178

  14. Ultrasonic Characterization of Fatigue Cracks in Composite Materials

    Science.gov (United States)

    Workman, Gary L.; Watson, Jason; Johnson, Devin; Walker, James; Russell, Sam; Thom, Robert (Technical Monitor)

    2002-01-01

    Microcracking in composite structures due to combined fatigue and cryogenic loading can cause leakage and failure of the structure and can be difficult to detect in-service. In aerospace systems, these leaks may lead to loss of pressure/propellant, increased risk of explosion and possible cryo-pumping. The success of nondestructive evaluation to detect intra-ply microcracking in unlined pressure vessels fabricated from composite materials is critical to the use of composite structures in future space systems. The work presented herein characterizes measurements of intraply fatigue cracking through the thickness of laminated composite material by means of correlation with ultrasonic resonance. Resonant ultrasound spectroscopy provides measurements which are sensitive to both the microscopic and macroscopic properties of the test article. Elastic moduli, acoustic attenuation, and geometry can all be probed. The approach is based on the premise of half-wavelength resonance. The method injects a broadband ultrasonic wave into the test structure using a swept frequency technique. This method provides dramatically increased energy input into the test article, as compared to conventional pulsed ultrasonics. This relative energy increase improves the ability to measure finer details in the materials characterization, such as microcracking and porosity. As the microcrack density increases, more interactions occur with the higher frequency (small wavelength) components of the signal train causing the spectrum to shift toward lower frequencies. Several methods are under investigation to correlate the degree of microcracking from resonance ultrasound measurements on composite test articles including self organizing neural networks, chemometric techniques used in optical spectroscopy and other clustering algorithms.

  15. Polymer composites filled with powders as polymer graded materials

    Directory of Open Access Journals (Sweden)

    J. Stabik

    2010-11-01

    Full Text Available Purpose: The goal of this paper is to present general overview of research results on Polymeric Gradient Materials (PGMs performed in Division of Metallic and Polymeric Materials Processing of Silesian University of Technology. Achievements in research on production technologies, compositions and properties are presented.Design/methodology/approach: Two basic technologies that were used for preparing polymeric gradient composites filled with powders are presented (centrifugal and gravity casting. Composites based on epoxy resin and filled with iron, ferrite, graphite, coal powders are characterized. Among other, the following properties were tested: surface resistivity, coefficient of friction, magnetic induction, filler particles distribution in polymeric matrix and others.Findings: Casting methods presented in this article can successfully be used to produce polymer composites characterized by gradual distribution of powder content and by this way by gradual distribution of properties. Results show that it is possible not only to achieve but also in some extend to control gradient of filler concentration. Especially in centrifugal casting is possible to influence gradient of filler concentration and in this way gradient of many properties.Research limitations/implications: The main problem in presented researches was to introduce higher quantities of filler. The side effect of high filler content was high viscosity. Filler particles were added to the epoxy matrix in range from 3vol.% to 50vol.% depending on filler properties, method of casting etc.Practical implications: Elaborated PGMs may be applied in many fields such as medicine, electronics, mining industry, machine building industry and many others.Originality/value: New type of polymeric gradient composites were achieved using centrifugal and gravity casting technique. Influence of casting parameters, concentration and type of filler on composites properties was researched.

  16. Functionally Graded Dual-Nanoparticulate-Reinforced Aluminum Matrix Composite Materials

    International Nuclear Information System (INIS)

    Functionally graded carbon nanotubes (CNT) and nano Silicon carbide (nSiC) reinforced aluminum (Al) matrix composite materials were fully densified by a simple ball milling and hot-pressing processes. The nSiC was used as a physical mixing agent to increase dispersity of the CNT in the Al particles. It was observed that the CNT was better dispersed in the Al particles with a nSiC mixing agent compared to without it used. SEM micrograph showed that the interface of the each layers had very tightly adhesion without any serious pores and micro-cracks. This functionally graded dual-nanoparticulate-reinforced Al matrix composite by powder metallurgical approach could also be applied to comples matrix materials.

  17. Theoretical determination of thermal diffusivity of composite material

    Institute of Scientific and Technical Information of China (English)

    Thomas Kabayabaya; Fan Yu; Xinxin Zhang

    2004-01-01

    A very simple model based on the Quadrupole method was used in the theoretical analysis of thermal diffusivity of composite materials of Cu-PVC, PVC-Cu-PVC, and Cu-PVC-Cu. The use of MATLAB software with a return to real space using the Stehfest algorithm makes the time of calculation very short. The thermal responses on the rear face of each considered sample, which determine the thermal diffusivity were represented. A mathematical demonstration which confirmed the results was given. Thermal diffusivity determined from the rear face thermal responses were compared with the results of the thermal diffusivity calculated by considering the composite materials to be homogeneous, and a discussion on the two kinds of results was provided.

  18. Gamma absorption technique in elemental analysis of composite materials

    International Nuclear Information System (INIS)

    Highlights: ► Application of gamma-ray absorption technique in elemental analysis. ► Determination of elemental composition of some bronze and gold alloys. ► Determination of some heavy elements in water. - Abstract: Expressions for calculating the elemental concentrations of composite materials based on a gamma absorption technique are derived. These expressions provide quantitative information about elemental concentrations of materials. Calculations are carried out for estimating the concentrations of copper and gold in some alloys of bronze and gold. The method was also applied for estimating the concentrations of some heavy elements in a water matrix highlighting the differences with photon attenuation measurements. Theoretical mass attenuation coefficient values were obtained using the WinXCom program. A high-resolution gamma-ray spectrometry based on high purity germanium detector (HPGe) was employed to measure the attenuation of a strongly collimated monoenergetic gamma beam through samples.

  19. Nondestructive evaluation of a ceramic matrix composite material

    Science.gov (United States)

    Grosskopf, Paul P.; Duke, John C., Jr.

    1992-01-01

    Monolithic ceramic materials have proven their usefulness in many applications, yet, their potential for critical structural applications is limited because of their sensitivity to small imperfections. To overcome this extreme sensitivity to small imperfections, ceramic matrix composite materials have been developed that have the ability to withstand some distributed damage. A borosilicate glass reinforced with several layers of silicon-carbide fiber mat has been studied. Four-point flexure and tension tests were performed not only to determine some of the material properties, but also to initiate a controlled amount of damage within each specimen. Acousto-ultrasonic (AU) measurements were performed periodically during mechanical testing. This paper will compare the AU results to the mechanical test results and data from other nondestructive methods including acoustic emission monitoring and X-ray radiography. It was found that the AU measurements were sensitive to the damage that had developed within the material.

  20. Microscale Fracture of Composite Materials for Wind Turbine Blades

    DEFF Research Database (Denmark)

    Martyniuk, Karolina

    shown, that the fracture parameters of an interface between dissimilar materials depends on mode mixity of the crack tip. Therefore, the fracture parameters of the fibre/matrix interface must be determined in terms of mode mixity. Experimental investigation must be conducted in order to provide reliable...... materials models can be developed if the understanding of the microscale damage- the first stage of material failure- is increased. Therefore it is important to characterize materials’ microstructures and micro-cracks initiation and propagation.The microstructure of fibre reinforced composite materials...... characterized in terms of interfacial shear strength or Mode II interface fracture toughness. However, for the fibres oriented off the principle stress direction, fibre/matrix debonding occurs under mixed mode conditions. The mode mixity of an interfacial crack tip is not considered in many studies. It has been...

  1. Production and Properties of Composite Material Comprising Gd Multiscale Particles

    Directory of Open Access Journals (Sweden)

    Jaworski Jacek

    2015-02-01

    Full Text Available The article presents a novel method of producing Gd particles and preserving them from oxidation. The particles were produced in liquid paraffin by means of AC electric discharge and stored in the solidified paraffin. After seven months, the surface of the Gd was found to be exempt of oxidation. Moreover a composite material formed from mixing paraffin with Gd particles was conductive and magnetic and also presented photovoltaic effect. This method is a promising means of producing, at an industrial scale, particles from materials extremely sensitive to environment such as rare earth materials. Also the new material consisted of Gd particles in a paraffin matrix can find applications in many branches of industry.

  2. Multimaterial magnetically assisted 3D printing of composite materials

    Science.gov (United States)

    Kokkinis, Dimitri; Schaffner, Manuel; Studart, André R.

    2015-10-01

    3D printing has become commonplace for the manufacturing of objects with unusual geometries. Recent developments that enabled printing of multiple materials indicate that the technology can potentially offer a much wider design space beyond unusual shaping. Here we show that a new dimension in this design space can be exploited through the control of the orientation of anisotropic particles used as building blocks during a direct ink-writing process. Particle orientation control is demonstrated by applying low magnetic fields on deposited inks pre-loaded with magnetized stiff platelets. Multimaterial dispensers and a two-component mixing unit provide additional control over the local composition of the printed material. The five-dimensional design space covered by the proposed multimaterial magnetically assisted 3D printing platform (MM-3D printing) opens the way towards the manufacturing of functional heterogeneous materials with exquisite microstructural features thus far only accessible by biological materials grown in nature.

  3. Analysis of a new composite material for watercraft manufacturing

    Science.gov (United States)

    Wahrhaftig, Alexandre; Ribeiro, Henrique; Nascimento, Ademar; Filho, Milton

    2016-07-01

    In this paper, we investigate the properties of an alternative material for use in marine engineering, namely a rigid and light sandwich-structured composite made of expanded polystyrene and fiberglass. Not only does this material have an improved section modulus, but it is also inexpensive, light, easy to manipulate, and commercially available in various sizes. Using a computer program based on the finite element method, we calculated the hogging and sagging stresses and strains acting on a prismatic boat model composed of this material, and determined the minimum sizes and maximum permissible stresses to avoid deformation. Finally, we calculated the structural weight of the resulting vessel for comparison with another structure of comparable dimensions constructed from the commonly used core material Divinycell.

  4. DOE/MSU composite material fatigue database: Test methods, materials, and analysis

    Energy Technology Data Exchange (ETDEWEB)

    Mandell, J.F.; Samborsky, D.D. [Montana State Univ., Bozeman, MT (United States). Dept. of Chemical Engineering

    1997-12-01

    This report presents a detailed analysis of the results from fatigue studies of wind turbine blade composite materials carried out at Montana State University (MSU) over the last seven years. It is intended to be used in conjunction with the DOE/MSU composite Materials Fatigue Database. The fatigue testing of composite materials requires the adaptation of standard test methods to the particular composite structure of concern. The stranded fabric E-glass reinforcement used by many blade manufacturers has required the development of several test modifications to obtain valid test data for materials with particular reinforcement details, over the required range of tensile and compressive loadings. Additionally, a novel testing approach to high frequency (100 Hz) testing for high cycle fatigue using minicoupons has been developed and validated. The database for standard coupon tests now includes over 4,100 data points for over 110 materials systems. The report analyzes the database for trends and transitions in static and fatigue behavior with various materials parameters. Parameters explored are reinforcement fabric architecture, fiber content, content of fibers oriented in the load direction, matrix material, and loading parameters (tension, compression, and reversed loading). Significant transitions from good fatigue resistance to poor fatigue resistance are evident in the range of materials currently used in many blades. A preliminary evaluation of knockdowns for selected structural details is also presented. The high frequency database provides a significant set of data for various loading conditions in the longitudinal and transverse directions of unidirectional composites out to 10{sup 8} cycles. The results are expressed in stress and strain based Goodman Diagrams suitable for design. A discussion is provided to guide the user of the database in its application to blade design.

  5. Application of Composite Materials in the Fire Explosion Suppression System

    Institute of Scientific and Technical Information of China (English)

    REN Shah

    2012-01-01

    In order to lighten the weight of the special vehicles and improve their mobility and flexibility, the weight of all subsystems of the whole vehicle must be reduced in the general planning. A fire explosion suppression system is an important subsystem for the self-protection of vehicle, protection of crews and safety of a vehicle. The performances of the special vehicles determine their survival ability and combat capability. The composite bottle is made of aluminum alloy with externally wrapped carbon fiber ; it has been proven by a large number of tests that the new type explosion suppression fire distinguisher made of such composite materials applied in the special vehicle has reliable performance, each of its technical indexes is higher or equal to that of a steel distinguisher, and the composites can also optimize the assembly structure of the bottle, and improve the reliability and corrosion resistance. Most important is that the composite materials can effectively lighten the weight of the fire explosion suppression system to reach the target of weight reduction of the subsystem in general planning.

  6. New topics on nanoindentation of polymers and composite materials

    Science.gov (United States)

    Martinez Hernandez, Ricardo

    In this study, nanoindentation was used to determine Young's modulus of homogeneous plastic materials as well as inhomogeneous epoxy woven fabric composites using various indenters. In the first part, homogeneous PMMA and polycarbonate were characterized using conical and spherical indenters. The conventional approach of the inverse analysis was modified in order to account for effects obtained during spherical nanoindentation. The experimental results were verified using FEA analysis in ABAQUS. It was found that viscous effects were present in conical nanoindentations which led to an overestimation of contact stiffness. The second part, the response of carbon and glass fiber woven fabric epoxy composites was investigated using Berkovich and spherical indenters. Localized nanoindentation was performed using the Berkovich probe in both materials which led to determination of glass fibers and matrix stiffnesses. The anisotropic nature of the response was treated modifying the classical approach to calculate transverse modulus of a unidirectional composite. Finally, fiber volume ratios were calculated according to type of composite and indenter used.

  7. Nondestructive evaluation of critical composite material structural elements

    Science.gov (United States)

    Duke, John C., Jr.; Lesko, John J.; Weyers, R.

    1996-11-01

    A small span bridge that has suffered corrosive deterioration of a number of the steel structural members is in the process of being rehabilitated with glass and carbon fiber reinforced, pultruded polymer structural beams. As part of a comprehensive research program to develop methods for modeling long term durability of the composite material, nondestructive evaluation if being used to provide a preliminary assessment of the initial condition of the beams as well as to monitor the deterioration of the beams during service.

  8. COMPOSITION AND METHOD FOR DEGRADATION OF KERATINACEOUS MATERIALS

    DEFF Research Database (Denmark)

    2015-01-01

    materials (such as e.g. feather and pig bristles). (FR)L'invention concerne une composition dégradant la kératine qui comprend au moins deux différentes kératinases actives isolées issues d'au moins deux familles de protéases MEROPS différentes, au moins une sérine endo-kératinase active appartenant à la...

  9. Hybrid Aluminum Composite Materials Based on Carbon Nanostructures

    Directory of Open Access Journals (Sweden)

    Tatiana S. Koltsova

    2015-09-01

    Full Text Available We investigated formation of carbon nanofibers grown by chemical deposition (CVD method using an acetylene-hydrogen mixture on the surface of micron-sized aluminum powder particles. To obtain uniform distribution of the carbon nanostructures on the particles we deposited nickel catalyst on the surface by spraying from the aqueous solution of nickel nitrate. It was found that increasing the time of the synthesis lowers the rate of growth of carbon nanostructures due to the deactivation of the catalyst. The Raman spectroscopy measurements confirm the presence of disordered carbon corresponding to CNFs in the specimen. X-ray photoelectron spectroscopy showed the presence of aluminum carbide in the hot pressed samples. An aluminum composite material prepared using 1 wt.% CNFs obtained by uniaxial cold pressing and sintering showed 30% increase in the hardness compared to pure aluminum, whereas the composites prepared by hot pressing showed 80% increase in the hardness. Composite materials have satisfactory ductility. Thus, the aluminum based material reinforced with carbon nanostructures should be appropriate for creating high-strength and light compacts for aerospace and automotive applications and power engineering.DOI: http://dx.doi.org/10.5755/j01.ms.21.3.7355

  10. Characterization of Triaxial Braided Composite Material Properties for Impact Simulation

    Science.gov (United States)

    Roberts, Gary D.; Goldberg, Robert K.; Biniendak, Wieslaw K.; Arnold, William A.; Littell, Justin D.; Kohlman, Lee W.

    2009-01-01

    The reliability of impact simulations for aircraft components made with triaxial braided carbon fiber composites is currently limited by inadequate material property data and lack of validated material models for analysis. Improvements to standard quasi-static test methods are needed to account for the large unit cell size and localized damage within the unit cell. The deformation and damage of a triaxial braided composite material was examined using standard quasi-static in-plane tension, compression, and shear tests. Some modifications to standard test specimen geometries are suggested, and methods for measuring the local strain at the onset of failure within the braid unit cell are presented. Deformation and damage at higher strain rates is examined using ballistic impact tests on 61- by 61- by 3.2-mm (24- by 24- by 0.125-in.) composite panels. Digital image correlation techniques were used to examine full-field deformation and damage during both quasi-static and impact tests. An impact analysis method is presented that utilizes both local and global deformation and failure information from the quasi-static tests as input for impact simulations. Improvements that are needed in test and analysis methods for better predictive capability are examined.

  11. Boron carbide/carbon composite material and production process therefor

    International Nuclear Information System (INIS)

    The boron carbide/carbon composite material of the present invention comprises from 15 to 40% by volume of graphite and the balance of two kinds of powdery boron carbides X and Y having different average grain sizes. The average grain size of the powdery boron carbide X is less than 1/2 of the average grain size of the boron carbide Y, and the composite material comprises more than 10% by volume of the powdery boron carbide X and more than 30% by volume of the powdery boron carbide Y. They are press-molded under heating at a temperature range of 480 to 600degC, followed by sintering. A binder pitch of less evaporation ingredient melting upon heating is used as a binder. Since the pitch of satisfactory melting property is used, there is no worry that binding property lacks to reduce the lowering of the strength even if a great amount of powdery boron carbide is added. Further, since a carbonization yield is improved due to less evaporation content, density and strength of the composite material can be increased. (T.M.)

  12. Consolidation modeling of fibre reinforced thermoplastic composite materials

    International Nuclear Information System (INIS)

    Thermoplastic matrix composites offer rapid, clean processing compared to their thermoset counterparts. In automotive applications they also provide useful toughness and recyclability. Recent developments in co- mingling technology consisting of uniform combination of reinforcement and matrix have provided a new hybrid yam which facilitates a range of fabrication options combined with the potential for relatively low pressure processing. Both isothermal and non-isothermal compression moulding processes have successfully been used to produce thermoplastic composite materials while maintaining various process parameters. These process parameters including mainly pressure and temperature have a major influence on the final quality of the component including void content due to high melt viscosity of thermoplastic. A mathematical model has been developed and described in this paper that monitors these process parameters and their effect on the quality of the composite material. The results thus obtained were compared with the experimental results obtained by making flat plaques and tubular parts. Co-mingled material used during the experimental and modeling consisted of glass fibre as a reinforcement and polypropylene as the matrix. (author)

  13. Influence of composition on friction-wear behavior of composite materials reinforced by brass fibers

    Institute of Scientific and Technical Information of China (English)

    JIA Xian; LING Xiaomei

    2003-01-01

    In the study, for the composite materials reinforced by brass fibers, the influence of dominant ingredients, such as organic adhesion agent, cast iron debris, brass fiber, and graphite powder, on the friction-wear characteristics was investigated. The friction-wear experiment was carried out on the block-on-ring tribometer MM200. The worn surfaces of the friction pair consisting of the composite materials and grey cast iron HT200 under dry sliding friction were examined using scanning electron microscope (SEM), energy dispersive analysis (EDX) and differential thermal analysis-thermogravimetric analysis (DTA-TAG). The experimental results showed that the friction coefficient and the wear loss of the composite material increase obviously with the increase of cast iron debris content, but decrease obviously with the increase of graphite powder content, and increase a little when the mass fraction of brass fiber was over 19%, and the orientation of brass fiber has obvious influence on friction-wear property. When the mass fraction of organic adhesion agent was about 10-11%, the composite materials have an excellent friction-wear performance. The friction heat can pyrolyze organic ingredient in worn surface layer.

  14. Calcium Sulfate in Atacama Desert Basalt: A Possible Analog for Bright Material in Adirondack Basalt, Gusev Crater

    Science.gov (United States)

    Sutter, B.; Golden, D. C.; Amundson, R.; Chong-Diaz, G.; Ming, D. W.

    2007-01-01

    The Atacama Desert in northern Chile is one of the driest deserts on Earth (calcium sulfate (Ca-SO4) which was later confirmed by SEM/EDS analysis. This work examines the Ca-SO4 of Atacama basalt in an effort to provide insight into the possible nature of the bright material in the Adirondack basalt of Gusev Crater. The objectives of this work are to (i) discuss variations in Ca-SO4 crystal morphology in the vesicles and (ii) examine the Ca-SO4 interaction(s) with the basalt interior.

  15. Composite material pedestrian bridge for the Port of Bilbao

    International Nuclear Information System (INIS)

    Composite materials in comparison to traditional ones, steel and concrete, present advantages in civil works construction: lower weight, higher corrosion resistance (especially in the marine environment), and ease of installation. On the other hand, fabrication costs are generally higher. This is the reason why this technology is not widely used. This work illustrates the process followed for the design, fabrication and installation of a composite material pedestrian bridge in the Port of Bilbao (Northern Spain). In order to reduce the price of the bridge, the use of low cost materials was considered, therefore polyester resin was selected as the polymeric matrix, and glass fibres as reinforcement. Two material choices were studied. Currently in the market there is high availability of carbon nanoparticles: carbon nanotubes (CNT) and carbon nanofibres (CNF), so it was decided to add this kind of nanoparticles to the reference material with the objective of improving its mechanical properties. The main challenge was to transfer the CNT and CNF excellent properties to the polymeric matrix. This requires dispersing the nanoreinforcements as individual particles in the polymeric matrix to avoid agglomerates. For this reason, an advanced high shear forces dispersion technique (called 'three roll mills') was studied and implemented. Also surface functionalization of the nanoreinforcements by chemical treatment was carried out. Herein, a comparison is performed between both materials studied, the explanation of the employment of the reference material (without nanoreinforcement) as the one used in the fabrication of the pedestrian bridge is justified and, finally, the main characteristics of the final design of the structural element are described.

  16. Synthesis and Properties of Electroconductive Polymeric Composite Material Based on Polypyrrole

    OpenAIRE

    Ilicheva, N. S.; Kitaeva, N. K.; Duflot, V. R.; V. I. Kabanova

    2012-01-01

    A technique is proposed for obtaining electroconductive, mechanically strong, and elastic composite material based on polypyrrole and hydrophilized polyethylene. The relationship is established between the process parameters and properties of the composite material such as electroconductivity and mechanical strength. Several methods are considered in the view of increasing electroconductivity of the material. Physical and mechanical properties of the composite material are investigated.

  17. Theoretical Prediction of Dynamic Composite Material Properties for Hypervelocity Impact Simulations

    OpenAIRE

    Ryan, S; Wicklein, M.; Mouritz, A.; Riedel , W.; Schäfer, F.; Thoma, K

    2009-01-01

    Abstract Recent advances in the description of fibre-reinforced polymer composite material behaviour under extreme loading rates provide a significant extension in capabilities for numerical simulation of hypervelocity impact on composite satellite structures. Given the complexity of the material model, extensive material characterisation is required, however, as the properties of composite materials are commonly tailored for a specific application, experimental characterisation is...

  18. Polyvinyl alcohol–cellulose composite: a taste sensing material

    Indian Academy of Sciences (India)

    Sarmishtha Majumdar; Basudam Adhikari

    2005-12-01

    There are reports of fabrication of taste sensor by adsorbing lipids into Millipore filter paper. With this lipid based sensor, it has been found that the taste sensing efficiency of membrane can be remarkably improved. We have made an attempt to prepare taste sensor material by using functionalized polymer without any lipid. PVA–cellulose composite has been modified to use as the sensor material. The research work covers polymer membrane preparation, morphology study and structural characterization of the membrane and study of the taste sensing characteristics of this membrane for five different taste substances. PVA–cellulose composite membrane was modified by phosphorylation with POCl3. FTIR spectroscopic analysis, XRD analysis and SEM were done to get an idea about the structure and morphology of the prepared phosphorylated PVA–cellulose composite membrane. The sensor characteristics like temporal stability, response stability, response to different taste substances, and reproducibility of sensing performance were studied using phosphorylated PVA–cellulose composite membrane. Sensor device prepared with this membrane has shown distinct response patterns for different taste substances in terms of membrane potential. Threshold concentrations of phosphorylated PVA–cellulose composite membrane for HCl, NaCl, Q-HCl, sucrose and MSG are 0.001 mM, 0.001 mM, 0.001 mM, 0.001 mM and 0.009 mM, respectively. The threshold concentrations are below human threshold concentrations. Membranes also showed characteristic response patterns for organic acids like acetic acid, citric acid, formic acid etc, mineral acids like HCl, H2SO4 and HNO3 salts, bitter substances, sweet substances and umami substances. Sensor device prepared with this membrane has excellent shelf life.

  19. Standard Test Methods for Constituent Content of Composite Materials

    CERN Document Server

    American Society for Testing and Materials. Philadelphia

    2009-01-01

    1.1 These test methods determine the constituent content of composite materials by one of two approaches. Method I physically removes the matrix by digestion or ignition by one of seven procedures, leaving the reinforcement essentially unaffected and thus allowing calculation of reinforcement or matrix content (by weight or volume) as well as percent void volume. Method II, applicable only to laminate materials of known fiber areal weight, calculates reinforcement or matrix content (by weight or volume), and the cured ply thickness, based on the measured thickness of the laminate. Method II is not applicable to the measurement of void volume. 1.1.1 These test methods are primarily intended for two-part composite material systems. However, special provisions can be made to extend these test methods to filled material systems with more than two constituents, though not all test results can be determined in every case. 1.1.2 The procedures contained within have been designed to be particularly effective for ce...

  20. Fatigue Crack Measurement in Composite Materials by Ultrasonic Methods

    Science.gov (United States)

    Walker, James L.; Russell, Samuel S.; Suits, Michael W.; Workman, Gary L.; Watson, Jason M.; Thom, Robert (Technical Monitor)

    2002-01-01

    The nondestructive detection of intra-ply microcracking in unlined pressure vessels fabricated from composite materials is critical to ensuring mission success. Microcracking in composite structures due to combined fatigue and cryogenic thermal loading can be very troublesome to detect in-service and when it begins to link through the thickness can cause leakage and failure of the structure. These leaks may lead to loss of pressure/propellant, increased risk of explosion and possible cryo-pumping. The work presented herein develops a method and an instrument to locate and measure intraply fatigue cracking through the thickness of laminated composite material by means of correlation with ultrasonic resonance. Resonant ultrasound spectroscopy provides measurements which are, sensitive to both the microscopic and macroscopic properties of an object. Elastic moduli, acoustic attenuation, and geometry can all be probed. The approach is based on the premise of half-wavelength resonance. The method injects a broadband ultrasonic wave into the test structure using a swept frequency technique. This method provides dramatically increased energy input into the test article, as compared to conventional spike pulsed ultrasonics. This relative energy increase improves the ability to measure finer details in the materials character, such as micro-cracking and porosity. As the micro-crack density increases, more interactions occur with the higher frequency (small wavelength) components of the signal train causing the spectrum to shift toward lower frequencies. Preliminary experiments have verified a measurable effect on the resonance spectrum of the ultrasonic data to detect microcracking. Methods involving self organizing neural networks and other clustering algorithms show that the resonance ultrasound signatures from composites vary with the degree of microcracking and can be separated and identified.

  1. Serum Calcium Level in Hypertension

    OpenAIRE

    Hazari, Mohammed Abdul Hannan; Arifuddin, Mehnaaz Sameera; Muzzakar, Syed; Reddy, Vontela Devender

    2012-01-01

    Background: The alterations in extracellular calcium level may influence intracellular calcium level and possibly play a role in the pathogenesis of essential hypertension. Aim: The purpose was to find out the association between serum calcium levels and hypertension; and to compare the serum calcium levels between normotensive controls, hypertensive subjects on calcium channel blockers, and hypertensive subjects on antihypertensive medication other than calcium channel blockers. Materials an...

  2. Corrosion and tribological properties of basalt fiber reinforced composite materials

    Science.gov (United States)

    Ha, Jin Cheol; Kim, Yun-Hae; Lee, Myeong-Hoon; Moon, Kyung-Man; Park, Se-Ho

    2015-03-01

    This experiment has examined the corrosion and tribological properties of basalt fiber reinforced composite materials. There were slight changes of weight after the occurring of corrosion based on time and H2SO4 concentration, but in general, the weight increased. It is assumed that this happens due to the basalt fiber precipitate. Prior to the corrosion, friction-wear behavior showed irregular patterns compared to metallic materials, and when it was compared with the behavior after the corrosion, the coefficient of friction was 2 to 3 times greater. The coefficient of friction of all test specimen ranged from 0.1 to 0.2. Such a result has proven that the basalt fiber, similar to the resin rubber, shows regular patterns regardless of time and H2SO4 concentration because of the space made between resins and reinforced materials.

  3. Multi-Material Design Optimization of Composite Structures

    DEFF Research Database (Denmark)

    Hvejsel, Christian Frier

    design of laminated composite structures is studied including the problem of orienting orthotropic material optimally. The approach taken in this work is to consider this multi-material design problem as a generalized topology optimization problem including multiple candidate materials with known...... or random search techniques. Thus, a main issue is the question of how to parametrize the originally discrete optimization problem in a manner making it suitable for solution using gradient-based algorithms. This is a central theme throughout the thesis and in particular two gradient-based approaches...... consists of a relaxation-based search heuristic that accelerates a Generalized Benders' Decomposition technique for global optimization and enables the solution of medium-scale problems to global optimality. Improvements in the ability to solve larger problems to global optimality are found and potentially...

  4. Voigt waves in electro-optic homogenized composite materials

    Science.gov (United States)

    Mackay, Tom G.

    2014-08-01

    A study was undertaken into Voigt wave propagation in a homogenized composite material (HCM). The HCM investigated arose from a porous electro-optic host material infiltrated by a fluid of refractive index na, considered in the long-wavelength regime. The extended Bruggeman homogenization formalism was employed to estimate the constitutive parameters of the HCM. In principle, the directions which support Voigt wave propagation in the HCM may be controlled by means of an applied dc electric field; and the degree of control may be sensitive to the porosity of the host material, the shapes, sizes and orientations of the pores, as well as the refractive index na. Here the theoretical methodology is presented; numerical results are presented elsewhere.

  5. Calcium phosphate precipitation on the surface of HA-G-Ti composite under physiologic conditions.

    Science.gov (United States)

    Ban, S; Maruno, S; Iwata, H; Itoh, H

    1994-01-01

    Hydroxyapatite-glass-titanium (HA-G-Ti) functionally gradient composite plates bound face-to-face by nylon wire were soaked in a simulated body fluid. The gap between the plates was filled with the precipitates after soaking for 6 months, and a tight chemical bond was formed between them. Field emission-type (FE) scanning electron microscopy (SEM) and transmission electron microscopy observations revealed that the growth rate and morphology of the precipitates differed widely from the outside portion to the inside one on the surface region of the composite plates. In the portion relatively near the outside, the mutually bonded portion, needle-like precipitates with preferred orientation to the c-axis were markedly observed. From the results of Fourier transform infrared spectroscopy and energy dispersive x-ray microanalysis, it was found that the precipitates were Ca-deficient carbonate apatite with low crystallinity. On the other hand, HA-G-Ti composite rods were implanted in the femur of beagle dogs for 3 months. FE-SEM observations demonstrated that needle-like precipitates were deposited on both the surfaces of the composite and bone at the portion having a narrow gap, about 0.1-0.2 mm between them prepared deliberately before implantation. It was found that both the morphologies and the composition of the precipitates in vivo were similar to those in vitro. It is concluded that the HA particles on the surface of the composite act as nucleation sites for precipitation in physiologic environments, whereas the glass matrix is independent to it. PMID:8126030

  6. New Materials for Structural Composites and Protective Coatings

    Science.gov (United States)

    2008-01-01

    The objective of this Phase I project was to create novel conductive materials that are lightweight and strong enough for multiple ground support equipment and Exploration applications. The long-term goal is to combine these materials within specially designed devices to create composites or coatings with diagnostic capabilities, increased strength, and tunable properties such as transparency, electroluminescence, and fire resistance. One such technology application is a smart windows system. In such a system, the transmission of light through a window is controlled by electrical power. In the future, these materials may also be able to absorb sunlight and convert it into electrical energy to produce light, thereby creating a self-sufficient lighting system. This experiment, conducted in collaboration with the Georgia Institute of Technology, demonstrated enhancements in fabricating fiber materials from carbon nanotubes (CNT). These nanotubes were grown as forests in an ultra-high-purity chemical vapor deposition (CVD) furnace and then drawn, using novel processing techniques, into fibers and yarns that would be turned into filaments. This work was submitted to the Journal of Advanced Functional Materials. The CNT fibers were initially tested as filament materials at atmospheric pressure; however, even under high current loads, the filaments produced only random sparking. The CNT fibers were also converted into transparent, hydrophobic, and conductive sheets. Filament testing at low vacuum pressures is in progress, and the technology will be enhanced in 2008. As initial proof of the smart-windows application concept, the use of CNT sheets as composites/ protective coatings was demonstrated in collaboration with Nanocomp Technologies of Concord, New Hampshire.

  7. Scientific Opinion on the safety assessment of the active substances, sodium erythorbate, sodium carbonate, sodium bicarbonate, iron sulphate, activated carbon, cellulose, calcium hydroxide, calcium chloride and water, for use as active system in food contact materials

    Directory of Open Access Journals (Sweden)

    EFSA Panel on Food Contact Materials, Enzymes, Flavourings and Processing Aids (CEF

    2014-02-01

    Full Text Available This scientific opinion of EFSA Panel on Food Contact Materials, Enzymes, Flavourings and Processing Aids deals with the safety assessment of the active substances sodium erythorbate, sodium carbonate, sodium bicarbonate, iron sulfate, activated carbon, cellulose, calcium hydroxide, calcium chloride and water, used in mixture which is packed into sachets for absorbing oxygen/carbon dioxide emitting from/into the headspace surrounding packed food. All substances of this formulation have been evaluated and approved for use as additives in plastic food contact materials or as food additives. No migration of calcium, iron and sodium ions was detected. No volatile organic compounds other than carbon dioxide were detected at the limit of detection of 0.5 μg/l. The CEF Panel concluded that the use of the substances sodium erythorbate, sodium carbonate, sodium bicarbonate, iron sulfate, activated carbon, cellulose, calcium hydroxide, calcium chloride and water does not raise a safety concern when used in oxygen absorber/carbon dioxide emitter systems, in sachets that prevent the physical release of their contents into the food. The sachets are to be placed in the headspace of the packaging and as such may come into occasional contact with the food, e.g. during handling. The sachet should not come into direct contact with liquid foods or foods that have and external aqueous liquid phase on the surface (liquid or exudates.

  8. Calcium phosphate/chitosan composite coating: Effect of different concentrations of Mg{sup 2+} in the m-SBF on its bioactivity

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Jie [School of Chemistry Engineering and Technology, Harbin Institute of Technology, Harbin 150001 (China); Pharmacy College, Jiamusi University, Jiamusi 154007 (China); Dai, Changsong, E-mail: changsd@hit.edu.cn [School of Chemistry Engineering and Technology, Harbin Institute of Technology, Harbin 150001 (China); Wei, Jie [School of Chemistry Engineering and Technology, Harbin Institute of Technology, Harbin 150001 (China); School of Chemistry and Bioengineering, Suzhou Science Technology University, Suzhou 215009 (China); Wen, Zhaohui, E-mail: wenzhaohui1968@163.com [Department of neuro intern, First Affiliated Hospital of Harbin Medical University, Harbin 150001 (China); Zhang, Shujuan; Lin, Lemin [Department of neuro intern, First Affiliated Hospital of Harbin Medical University, Harbin 150001 (China)

    2013-09-01

    The purpose of this study was to investigate the effect of different concentration of Mg{sup 2+} in a modified simulated body fluid (m-SBF) on the bioactivity of calcium phosphate/chitosan composite coating. Calcium phosphate/chitosan composite coating was prepared on graphite substrate via electrophoretic deposition (EPD) followed by conversion in a phosphate buffer solution (PBS). The obtained samples were soaked in the m-SBF containing different concentration of Mg{sup 2+} for different times. And then, the composite coatings were assessed using X-ray diffractometer (XRD), Fourier-transformed infrared spectroscopy (FTIR), Raman spectra, and scanning electron microscope (SEM) with an energy dispersive spectrometer (EDS). The soaking solution was evaluated by inductively coupled plasma optical emission spectrometer (ICP-OES) test. The analytical results showed that hydroxyapatite (HA) and bone-like apatite (HCA) grew on the surface of calcium phosphate/chitosan composite coating after incubation in different m-SBF. With Mg{sup 2+} concentration in m-SBF increased from 1× Mg to 10× Mg, HA in the composite coating first presented a dissolving process and then a precipitating one slowly, while HCA presented a growing trend, continuously. The increasing of Mg{sup 2+} concentration in the m-SBF inhibited the total growing process of HA and HCA as a whole. The structure of the composite coating changed from spherical into irregular morphology with the concentration of Mg{sup 2+} increasing from 1× Mg to 10× Mg. Over all, with the Mg{sup 2+} concentration increasing, the bioactivity of calcium phosphate/chitosan composite coating tended to decrease.

  9. Calcium phosphate/chitosan composite coating: Effect of different concentrations of Mg2+ in the m-SBF on its bioactivity

    International Nuclear Information System (INIS)

    The purpose of this study was to investigate the effect of different concentration of Mg2+ in a modified simulated body fluid (m-SBF) on the bioactivity of calcium phosphate/chitosan composite coating. Calcium phosphate/chitosan composite coating was prepared on graphite substrate via electrophoretic deposition (EPD) followed by conversion in a phosphate buffer solution (PBS). The obtained samples were soaked in the m-SBF containing different concentration of Mg2+ for different times. And then, the composite coatings were assessed using X-ray diffractometer (XRD), Fourier-transformed infrared spectroscopy (FTIR), Raman spectra, and scanning electron microscope (SEM) with an energy dispersive spectrometer (EDS). The soaking solution was evaluated by inductively coupled plasma optical emission spectrometer (ICP-OES) test. The analytical results showed that hydroxyapatite (HA) and bone-like apatite (HCA) grew on the surface of calcium phosphate/chitosan composite coating after incubation in different m-SBF. With Mg2+ concentration in m-SBF increased from 1× Mg to 10× Mg, HA in the composite coating first presented a dissolving process and then a precipitating one slowly, while HCA presented a growing trend, continuously. The increasing of Mg2+ concentration in the m-SBF inhibited the total growing process of HA and HCA as a whole. The structure of the composite coating changed from spherical into irregular morphology with the concentration of Mg2+ increasing from 1× Mg to 10× Mg. Over all, with the Mg2+ concentration increasing, the bioactivity of calcium phosphate/chitosan composite coating tended to decrease.

  10. Preparation and characterization of calcium phosphate ceramics and composites as bone substitutes

    Science.gov (United States)

    Zhang, Xing

    Marine CaCO3 skeletons have tailored architectures created by nature, which give them structural support and other functions. For example, seashells have dense lamellar structures, while coral, cuttlebone and sea urchin spines have interconnected porous structures. In our experiments, seashells, coral and cuttlebone were hydrothermally converted to hydroxyapatite (HAP), and sea urchin spines were converted to Mg-substituted tricalcium phosphate (beta-TCMP), while maintaining their original structures. Partially converted shell samples have mechanical strength, which is close to that of compact human bone. After implantation of converted shell and spine samples in rat femoral defects for 6 weeks, there was newly formed bone growth up to and around the implants. Some new bone was found to migrate through the pores of converted spine samples and grow inward. These results show good bioactivity and osteoconductivity of the implants, indicating the converted shell and spine samples can be used as bone defect fillers. Calcium phosphate powders were prepared through different synthesis methods. Micro-size HAP rods were synthesized by hydrothermal method through a nucleation-growth mechanism. On the other hand, HAP particles, which have good crystallinity, were prepared by wet precipitation with further hydrothermal treatment. beta-TCP or beta-TCMP powders were prepared by a two-step process: wet precipitation of apatitic tricalcium phosphate ('precursor') and calcination of the precursor at 800°C for 3 hours. beta-TCMP or beta-TCP powders were also prepared by solid-state reactions from CaHPO4 and CaCO 3 with/without MgO. Biphasic calcium phosphate, which is mixture of HAP and beta-TCP, can be prepared though mechanical mixing of HAP and beta-TCP powders synthesized as above. Dense beta-TCP and beta-TCMP ceramics can be produced by pressing green bodies at 100MPa and further sintering above 1100°C for 2 hours. beta-TCMP ceramics ˜99.4% relative dense were prepared by

  11. Certification of Discontinuous Composite Material Forms for Aircraft Structures

    Science.gov (United States)

    Arce, Michael Roger

    New, high performance chopped, discontinuous, or short fiber composites (DFCs), DFCs, such as HexMC and Lytex, made by compression molding of randomly oriented pre-impregnated unidirectional tape, can be formed into complex geometry while retaining mechanical properties suitable for structural use. These DFCs provide the performance benefits of Continuous Fiber Composites (CFCs) in form factors that were previously unavailable. These materials demonstrate some notably different properties from continuous fiber composites, especially with respect to damage tolerance and failure behavior. These behaviors are not very well understood, and fundamental research efforts are ongoing to better characterize the material and to ease certification for future uses. Despite this, these new DFCs show such promise that they are already in service in the aerospace industry, for instance in the Boeing 787. Unfortunately, the relative novelty of these parts means that they needed to be certified by “point design”, an excess of physical testing, rather than by a mix of physical testing and finite element analysis, which would be the case for CFCs or metals. In this study, one particular approach to characterizing both linear-elastic and failure behaviors are considered. The Stochastic Laminate Analogy, which represents a novel approach to modeling DFCs, and its combination with a Ply Discount scheme. Owing to limited available computational resources, only preliminary results are available, but those results are quite promising and warrant further investigation.

  12. Design and Analysis of Leaf Spring with Composite materials

    Directory of Open Access Journals (Sweden)

    Mr. Tharigonda Niranjan Babu

    2014-08-01

    Full Text Available In automobile sector tends to increasing competition and innovation in design and tends to modify the existing products by new and advanced materials. Leaf springs are special kind of springs used in automobile suspension systems. The main function of leaf spring is not only to support vertical load but also to isolate road induced vibrations. It is subjected to millions of load cycles leading to fatigue failure. The introduction of composite materials has made it possible to reduce the weight of the leaf spring without any reduction in load carrying capacity and stiffness. Therefore the objective of this paper is to present a general study on the performance comparison of composite (E-Glass/Epoxy and Jute E-Glass leaf spring and conventional leaf spring. Leaf spring is modeled in CATIA V5R20 software and it is imported in ANSYS 12.0. The conventional composite leaf springs were analyzed under similar conditions using ANSYS software and the results are presented.

  13. Detection of defects in composite material by laser NDT system

    International Nuclear Information System (INIS)

    Digital Shearography is an optical nondestructive testing (NDT) technique that is being widely employed in production and quality control applications within aircraft, oil and gas, automotive and materials research, which is a big challenge for traditional NDT techniques. The purpose of our work is to develop a laser shearography non-destructive testing system which is capable of mapping stress distribution in Carbon Fiber Reinforced Polymer (CFRP) component. High intensity laser interferometer arrangement is utilized to map stress affected areas which leads to the assessment of the sample under investigation. The system provides a fast and real-time inspection capability in revealing defect through the mapping of high stress concentration areas. In this study, the laser system is utilized to test stress concentration area in Composite sample that contains defects. The Composite sample has the dimension of 40 mm width, 200 mm long and 200 mm height. The study shows that the system is capable to detect and observed the presence of moisture and debonding area in a composite sample. For comparison the Radiography technique is utilized to validate the location and shape of the same defect in the material. (author)

  14. Thermal analysis of metal foam matrix composite phase change material

    Science.gov (United States)

    Song, Xiange

    2015-06-01

    In this paper, CPCM (Composite Phase Change Material) was manufactured with metal foam matrix used as filling material. The temperature curves were obtained by experiment. The performance of heat transfer was analyzed. The experimental results show that metal foam matrix can improve temperature uniformity in phase change thermal storage material and enhance heat conduction ability. The thermal performance of CPCM is significantly improved. The efficiency of temperature control can be obviously improved by adding metal foam in phase change material. CPCM is in solid-liquid two-phase region when temperature is close to phase change point of paraffin. An approximate plateau appears. The plateau can be considered as the temperature control zone of CPCM. Heat can be transferred from hot source and be uniformly spread in thermal storage material by using metal foam matrix since thermal storage material has the advantage of strong heat storage capacity and disadvantage of poor heat conduction ability. Natural convection promotes the melting of solid-liquid phase change material. Good thermal conductivity of foam metal accelerates heat conduction of solid-liquid phase change material. The interior temperature difference decreases and the whole temperature becomes more uniform. For the same porosity with a metal foam, melting time of solid-liquid phase change material decreases. Heat conduction is enhanced and natural convection is suppressed when pore size of metal foam is smaller. The thermal storage time decreases and heat absorption rate increases when the pore size of metal foam reduces. The research results can be used to guide fabricating the CPCM.

  15. Design studies of interaction processes between melt reactor core material composition, coolant and construction material

    International Nuclear Information System (INIS)

    This effort presents results of the design studies performed for correct conducting of out-of-pile experiments at the National Nuclear Center of the Republic of Kazakhstan facilities to study interaction processes between the melt fuel composition and core materials, which might take place during accidents at the nuclear power plants. The design methods are considered to determine electromagnetic parameters of the facility melting unit - an induction melting furnace, to determine temperature fields in furnace construction component materials during the experiment process and at the moment of melt discharge. The methods are presented to calculate temperature fields and thermal flows in experimental device modelling a reactor vessel bottom when it contacts with the melt fuel composition. The results of thermal electric and hydraulic calculations are presented validating the experimental device operability designed to study the interaction processes between the melt fuel composition and reactor vessel bottom in simulating a residual energy release in the melt by direct current transmitting

  16. Compositions for enhancing hydroysis of cellulosic material by cellulolytic enzyme compositions

    Energy Technology Data Exchange (ETDEWEB)

    Quinlan, Jason; Xu, Feng; Sweeney, Matthew; Johansen, Katja Salomon

    2014-09-30

    The present invention relates to compositions comprising a GH61 polypeptide having cellulolytic enhancing activity and an organic compound comprising a carboxylic acid moiety, a lactone moiety, a phenolic moiety, a flavonoid moiety, or a combination thereof, wherein the combination of the GH61 polypeptide having cellulolytic enhancing activity and the organic compound enhances hydrolysis of a cellulosic material by a cellulolytic enzyme compared to the GH61 polypeptide alone or the organic compound alone. The present invention also relates to methods of using the compositions.

  17. Polyelectrolytes in the synthesis of bio-inspired composite materials

    Science.gov (United States)

    McKenna, Brandon J.

    2007-05-01

    This original research dissertation contains studies on complex coacervation, methods of modifying coacervates to create new materials as particularly applied to targeted drug delivery, and the use of coacervating polyanions for the assembly of intricate structures of calcium carbonate. Complex coacervation is a liquid-liquid phase separation that typically produces microspherical droplets from the combination of a variety of oppositely charged ions, including polymers and nanoparticles. The chemical space of coacervating components was found dependent on the number of charged groups and pH. Coacervates were shown to present chemically active surfaces that could be solidified by various methods, some of which also induced hollow interiors. The resulting assemblies were considered for targeted drug delivery by using superparamagnetic magnetite nanoparticles as assembling components. Control over microsphere sizes was obtained from variation of several parameters, and porosities were examined as a function of cross-linking extent to determine encapsulation capabilities. Coacervates were further found to direct mineral growth, first in the form of shells, and then in the form of complicated structures that require substrate interaction via a solution-amorphous-crystalline mechanism. A ternary phase diagram approach revealed a great diversity of morphologies that could be modulated by the action of coacervating polyanions. Detailed analysis of one particular stacked lamellar structure suggested an assembly mechanism that may have relevance for biomineralization of nacre.

  18. Calcium barium niobate as a functional material for broadband optical frequency conversion.

    Science.gov (United States)

    Sheng, Yan; Chen, Xin; Lukasiewicz, Tadeusz; Swirkowicz, Marek; Koynov, Kaloian; Krolikowski, Wieslaw

    2014-03-15

    We demonstrate the application of as-grown calcium barium niobate (CBN) crystal with random-sized ferroelectric domains as a broadband frequency converter. The frequency conversion process is similar to broadband harmonic generation in commonly used strontium barium niobate (SBN) crystal, but results in higher conversion efficiency reflecting a larger effective nonlinear coefficient of the CBN crystal. We also analyzed the polarization properties of the emitted radiation and determined the ratio of d32 and d33 components of the second-order susceptibility tensor of the CBN crystal. PMID:24690779

  19. Designing magnetic composite materials using aqueous magnetic fluids

    CERN Document Server

    Galicia, J A; Cousin, F; Guemghar, D; Menager, C; Cabuil, V

    2003-01-01

    In this paper, we report on how to take advantage of good knowledge of both the chemistry and the stability of an aqueous magnetic colloidal suspension to realize different magnetic composites. The osmotic pressure of the magnetic nanoparticles is set prior to the realization of the composite to a given value specially designed for the purpose for each hybrid material: magnetic particles in polymer networks, particles as probes for studying the structure of clay suspensions and shape modification of giant liposomes. First, we show that the introduction of magnetic particles in polyacrylamide gels enhances their Young modulus and reduces the swelling caused by water. The particles cause both a mechanical and an osmotic effect. The latter is strongly dependent on the ionic strength and is attributed to an attraction between particles and the polymeric matrix. In the second part, we determine the microscopic structure of suspensions of laponite as a function of concentration, by combining SANS and magneto-optica...

  20. Early detection of fatigue damage in composite materials

    Science.gov (United States)

    Salkind, M. J.

    1975-01-01

    Early detection of fatigue damage in composite materials by nondestructive inspection (NDI) techniques has been demonstrated for glass/epoxy, graphite/glass/epoxy, and graphite/epoxy composites. Modulus and temperature were monitored and a correlation between them observed. Axial modulus and torsional modulus changes were a function of the laminate orientation. Torsional modulus measurements and coin tap tests were performed at 0, 1 million, 5 million, and 10 million cycles, on axial fatigue specimens. Three distinct regions were noted. In the primary region a small but rapid change in stiffness was noted in the first few thousand cycles. This was followed by a secondary region of little or no stiffness change. The tertiary region was characterized by an increasing rate of stiffness change leading to fracture. NDI procedures including holographic interferometry, ultrasonics, penetrant, and X-ray radiography were evaluated for fatigue damage detection.