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Sample records for permeability mechanical properties

  1. Mechanical and permeability properties of milk protein films

    Directory of Open Access Journals (Sweden)

    Marília I.S. Folegatti

    1998-01-01

    Full Text Available Edible films present a potential alternative for replacing plastic films used for packaging in food industry. One of the major advantages is the environmental appeal of this technology, which produces no packaging waste. Some films made with other edible materials have found commercial applications, and many more are being developed using a myriad of food based components. This paper focuses on some important characteristics of films produced with sodium and calcium caseinates. The effects of caseinate type and concentration, plasticizer concentration and pH were studied. Major parameters investigated were solubility, tensile properties, water vapour and oxygen permeabilities. Caseinate films showed high solubility at pH range 6.0-8.0 and complete insolubility at pH 3.0 and 4.0. Calcium caseinate films had a higher tensile strength and a lower % elongation at break than sodium caseinate films. There was not significant difference in water vapour and oxygen permeabilities between sodium and calcium caseinate films.Filmes comestíveis representam uma alternativa potencial para a substituição de filmes plásticos .empregados em embalagem de alimentos. Uma de suas maiores vantagens relaciona-se com o problema de poluição ambiental por não gerar material residual. Filmes elaborados com outros materiais comestíveis não protéicos têm encontrado aplicação comercial e muitos outros ainda estão sendo pesquisados, usando uma grande variedade de componentes alimentares. Este trabalho estuda algumas características importantes dos filmes produzidos com caseinatos de sódio e de cálcio. Os efeitos do tipo e concentração de caseinato, concentração de plastificante e do pH são investigados. Os parâmetros pesquisados foram a solubilidade, propriedades de tração e permeabilidade a vapor de água e oxigênio. Filmes de caseinato apresentaram alta solubilidade na faixa de pH entre 6.0 e 8.0 e completa insolubilidade em pH 3.0 e 4.0. Maior

  2. Mechanical properties of permeable materials with an organized structure on the base of continuous metal fibers

    International Nuclear Information System (INIS)

    Karpinos, D.M.; Rutkovskij, A.E.; Zorin, V.A.; Ivanchuk, A.A.

    1979-01-01

    The mechanical properties were studied for permeable fibrous materials with an organized structure on the base of continuous metal fibers (from Kh18N9T steel) subjected to preliminary reprocessing volumetric net half-finished products. The effect of geometrical parameters of the net half-finished products and of their orientation in packing are shown to affect the mechanical properties within a wide range of porosities

  3. Material properties of biofilms – key methods for understanding permeability and mechanics

    Science.gov (United States)

    Billings, Nicole; Birjiniuk, Alona; Samad, Tahoura S.; Doyle, Patrick S.; Ribbeck, Katharina

    2015-01-01

    Microorganisms can form biofilms, which are multicellular communities surrounded by a hydrated extracellular matrix of polymers. Central properties of the biofilm are governed by this extracellular matrix, which provides mechanical stability to the three-dimensional biofilm structure, regulates the ability of the biofilm to adhere to surfaces, and determines the ability of the biofilm to adsorb gasses, solutes, and foreign cells. Despite their critical relevance for understanding and eliminating of biofilms, the materials properties of the extracellular matrix are understudied. Here, we offer the reader a guide to current technologies that can be utilized to specifically assess the permeability and mechanical properties of the biofilm matrix and its interacting components. In particular, we highlight technological advances in instrumentation and interactions between multiple disciplines that have broadened the spectrum of methods available to conduct these studies. We review pioneering work that furthers our understanding of the material properties of biofilms. PMID:25719969

  4. Effect of aggregate grain size distribution on properties of permeable ...

    African Journals Online (AJOL)

    ) ratio on the mechanical properties of permeable concrete is investigated. The aim of this study is to prepare permeable concrete mixture with optimum properties in terms of strength and permeability. For this purpose, five different permeable ...

  5. Evaluation of the magnetic and mechanical properties of reactor pressure vessel steels by incremental permeability change curve measurements

    International Nuclear Information System (INIS)

    Ebine, N.; Suzuki, M.

    2001-01-01

    Incremental permeability measurement was performed for two types of structural steels along with the magnetization of their hysteresis minor-loop. The obtained incremental permeability change curve has two sharp peaks, and the width between the two peaks is correlated with the coercivity. Hence the existence of good correlation was verified. On the basis of this result, nondestructive measurement experiments were carried out with planar coils to evaluate changes in the material properties of ferromagnetic structural steel plates. Changes in output voltages from planar coils with different test plates were correlated with their mechanical and magnetic properties. The correlation is so good that the measurement method adopted in this work could be used for nondestructive evaluation of material degradation in ferromagnetic structural steels. (author)

  6. Hydraulic and mechanical properties of natural fractures in low-permeability rock

    International Nuclear Information System (INIS)

    Pyrack-Nolte, L.J.; Myer, L.R.; Cook, N.G.W.; Witherspoon, P.A.

    1987-01-01

    The results of a comprehensive laboratory study of the mechanical displacement, permeability, and void geometry of single rock fractures in a quartz monzonite are summarized and analyzed. A metal-injection technique was developed that provided quantitative data on the precise geometry of the void spaces between the fracture surfaces and the areas of contact at different stresses. At effective stresses of less than 20 MPa fluid flow was proportional to the mean fracture aperture raised to a power greater than 3. As stress was increased, contact area was increased and void spaces become interconnected by small tortuous channels that constitute the principal impediment to fluid flow. At effective stresses higher than 20 MPa, the mean fracture aperture continued to diminish with increasing stress, but this had little effect on flow because the small tortuous flow channels deformed little with increasing stress

  7. Graphene immobilized enzyme/polyethersulfone mixed matrix membrane: Enhanced antibacterial, permeable and mechanical properties

    International Nuclear Information System (INIS)

    Duan, Linlin; Wang, Yuanming; Zhang, Yatao; Liu, Jindun

    2015-01-01

    Graphical abstract: - Highlights: • Lysozyme was immobilized on the surface of graphene oxide (GO) and reduced GO (RGO). • The novel hybrid membranes based on lysozyme and graphene were fabricated firstly. • These membranes showed good antibacterial and mechanical performance. - Abstract: Enzyme immobilization has been developed to address lots of issues of free enzyme, such as instability, low activity and difficult to retain. In this study, graphene was used as an ideal carrier for lysozyme immobilization, including graphene oxide (GO) immobilized lysozyme (GO-Ly) and chemically reduced graphene oxide (CRGO) immobilized lysozyme (CRGO-Ly). Herein, lysozyme as a bio-antibacterial agent has excellent antibacterial performance and the products of its catalysis are safety and nontoxic. Then the immobilized lysozyme materials were blended into polyethersulfone (PES) casting solution to prepare PES ultrafiltration membrane via phase inversion method. GO and CRGO were characterized by Fourier transform infrared spectroscopy (FTIR), Ultraviolet–visible spectrum (UV), X-ray diffraction (XRD), and transmission electron microscopy (TEM) and the immobilized lysozyme composites were observed by fluorescent microscopy. The results revealed that GO and CRGO were successfully synthesized and lysozyme was immobilized on their surfaces. The morphology, hydrophilicity, mechanical properties, separation properties and antibacterial activity of the hybrid membranes were characterized in detail. The hydrophilicity, water flux and mechanical strength of the hybrid membranes were significantly enhanced after adding the immobilized lysozyme. In the antibacterial experiment, the hybrid membranes exhibited an effective antibacterial performance against Escherichia coli (E. coli).

  8. Chemical composition, water vapor permeability, and mechanical properties of yuba film influenced by soymilk depth and concentration.

    Science.gov (United States)

    Zhang, Siran; Lee, Jaesang; Kim, Yookyung

    2018-03-01

    Yuba is a soy protein-lipid film formed during heating of soymilk. This study described yuba as an edible film by analyzing its chemical composition, water vapor permeability (WVP), and mechanical properties. Three yuba films were prepared by using different concentrations and depths of soymilk: HS (86 g kg -1 and 2.3 cm), LS (70 g kg -1 and 2.3 cm), and LD (70 g kg -1 and 3.0 cm). As yuba was successively skimmed, the protein, lipid, and SH content decreased, but carbohydrate and SS content increased. Though both the initial concentration and the depth of soymilk affect the properties of the films, the depth of soymilk influences WVP and tensile strength (TS) more. The WVP of the HS and LS changed the least (13-17 g mm kPa -1 m -2 day 1 ), while that of the LD changed the most (13-35 g mm kPa -1 m -2 day -1 ). There were no differences (P > 0.05) in the TS between the HS and LS. LD had the greatest decrease of TS and the lowest TS among the groups. The earlier the yuba films were collected, the greater the elongation of the films was: 129% (HS), 113% (LS), and 155% (LD). The initial concentration and the depth of soymilk changed the chemical composition and structure of the yuba films. The LS yuba produced more uniform edible films with good mechanical properties. © 2017 Society of Chemical Industry. © 2017 Society of Chemical Industry.

  9. Mechanical, Permeability, and Degradation Properties of 3D Designed Poly(1,8 Octanediol-co-Citrate)(POC) Scaffolds for Soft Tissue Engineering

    Science.gov (United States)

    Jeong, Claire G.; Hollister, Scott J.

    2015-01-01

    Poly(1,8-octanediol-co-citric acid) (POC) is a synthetic biodegradable elastomer that can be processed into 3D scaffolds for tissue engineering. We investigated the effect of designed porosity on the mechanical properties, permeability and degradation profiles of the POC scaffolds. For mechanical properties, scaffold compressive data was fit to a 1D nonlinear elastic model and solid tensile data was fit to a Neohookean incompressible nonlinear elastic model. Chondrocytes were seeded on scaffolds to assess the biocompatibility of POC. Increased porosity was associated with increased degradation rate, increased permeability, and decreased mechanical stiffness which also became less nonlinear. Scaffold characterization in this paper will provide design guidance for POC scaffolds to meet the mechanical and biological parameters needed for engineering soft tissues such as cartilage. PMID:20091910

  10. Mechanical properties of coal deformation and its influence on permeability%煤岩变形力学特性及其对渗透性的控制

    Institute of Scientific and Technical Information of China (English)

    孟召平; 王保玉; 谢晓彤; 薛彦东; 杜星原

    2012-01-01

    By the mechanical tests of the coal samples, the physical and mechanical properties of coal and the law of permeability during the complete stress-strain process were studied. It is shown that, compared with the rocks from coal roof and floor, the coal is more prone to plastic deformation with the property of lower mechanical strength, lower elastic modulus and higher Poisson' s ratio. For the coal samples which have obvious strain-softening character during the complete stress-strain process,first,the coal sample volume is compressed and the permeability of coal with stress in- creases slightly or permeability changes little in the micro-cracks closure and elastic deformation stage. After the stress increases higher than the elastic limit, the coal sample gets into the crack propagation stage. The volume strain of coal changs from compression to expansion. The permeability of coal first slowly and then sharply increases with an increas- ing of crack extension. During the strain-softening stage ,the coal permeability achieves the maximum and follows by a sharp decrease. The coal pel~neability after the peak strength is generally greater than that before the peak. For coal samples which have little strain-softening character or strain-hardening during the complete stress-strain process, the maximum permeability is mainly achieved in the plastic deformation stage before the peak. During the strain-hardening stage after the peak strength, the permeability decreases with an increasing of stress. Commonly, the coal permeability after the peak strength is generally less than that before the peak.%通过煤岩力学试验研究了煤岩物理力学性质和煤岩全应力-应变过程中的渗透规律。研究结果表明:煤的力学强度相对煤层顶底板岩石具有低强度、低弹性模量和高泊松比特性,易于产生塑性变形;在全应力-应变过程中具有明显应变软化现象的煤样,在微裂隙闭合和弹性变形阶段,煤岩体积被

  11. Effect of temperature and relative humidity on the water vapour permeability and mechanical properties of cassava starch and soy protein concentrate based edible films.

    Science.gov (United States)

    Chinma, C E; Ariahu, C C; Alakali, J S

    2015-04-01

    The effect of temperature and relative humidity on the water vapour permeability (WVP) and mechanical properties of cassava starch and soy protein concentrate (SPC) based edible films containing 20 % glycerol level were studied. Tensile strength and elastic modulus of edible films increased with increase in temperature and decreased with increase in relative humidity, while elongation at break decreased. Water vapour permeability of the films increased (2.6-4.3 g.mm/m(2).day.kPa) with increase in temperature and relative humidity. The temperature dependence of water vapour permeation of cassava starch-soy protein concentrate films followed Arrhenius relationship. Activation energy (Ea) of water vapour permeation of cassava starch-soy protein concentrate edible films ranged from 1.9 to 5.3 kJ/mol (R (2)  ≥ 0.93) and increased with increase in SPC addition. The Ea values were lower for the bio-films than for polyvinylidene chloride, polypropylene and polyethylene which are an indication of low water vapour permeability of the developed biofilms compared to those synthetic films.

  12. Effect of chitosan nanoparticles and pectin content on mechanical properties and water vapor permeability of banana puree films.

    Science.gov (United States)

    Martelli, Milena R; Barros, Taís T; de Moura, Márcia R; Mattoso, Luiz H C; Assis, Odilio B G

    2013-01-01

    Puree prepared from over-ripe peeled bananas was used as raw material for films processing in a laboratory padder. Pectin and glycerol as plasticizer were added in small concentrations and chitosan nanoparticles (88.79 ± 0.42 nm medium size) incorporated at 0.2% (dry weight basis) as reinforcement material. The mechanical properties, water vapor transmission, thermal stability, and scanning electron microscopy of fractured film surfaces were characterized. Both pectin and glycerol demonstrated an important role in promoting elongation and film handability as was expected. The incorporation of nanoparticles promoted noticeable improvement of the mechanical properties and acted in reducing the water vapor permeation rate, by 21% for films processed with pectin and up to 38% for films processed without pectin, when compared to the control (puree films with no pectin and nanoparticles additions). Microscopic observation revealed a denser matrix when nanoparticles are incorporated into the films. The development of films from fruit purees head to a new strategy for plastic processing from natural resources. The over-ripe or even waste banana can be adequately prepared for batch films processed with reasonable mechanical and barrier properties, suitable for applications in the food segment. The addition of small fractions of chitosan nanoparticles, form nanocomposites enhancing mechanical and thermal stability broadening potential film applications. © 2012 Institute of Food Technologists®

  13. Calculation of large scale relative permeabilities from stochastic properties of the permeability field and fluid properties

    Energy Technology Data Exchange (ETDEWEB)

    Lenormand, R.; Thiele, M.R. [Institut Francais du Petrole, Rueil Malmaison (France)

    1997-08-01

    The paper describes the method and presents preliminary results for the calculation of homogenized relative permeabilities using stochastic properties of the permeability field. In heterogeneous media, the spreading of an injected fluid is mainly sue to the permeability heterogeneity and viscosity fingering. At large scale, when the heterogeneous medium is replaced by a homogeneous one, we need to introduce a homogenized (or pseudo) relative permeability to obtain the same spreading. Generally, is derived by using fine-grid numerical simulations (Kyte and Berry). However, this operation is time consuming and cannot be performed for all the meshes of the reservoir. We propose an alternate method which uses the information given by the stochastic properties of the field without any numerical simulation. The method is based on recent developments on homogenized transport equations (the {open_quotes}MHD{close_quotes} equation, Lenormand SPE 30797). The MHD equation accounts for the three basic mechanisms of spreading of the injected fluid: (1) Dispersive spreading due to small scale randomness, characterized by a macrodispersion coefficient D. (2) Convective spreading due to large scale heterogeneities (layers) characterized by a heterogeneity factor H. (3) Viscous fingering characterized by an apparent viscosity ration M. In the paper, we first derive the parameters D and H as functions of variance and correlation length of the permeability field. The results are shown to be in good agreement with fine-grid simulations. The are then derived a function of D, H and M. The main result is that this approach lead to a time dependent . Finally, the calculated are compared to the values derived by history matching using fine-grid numerical simulations.

  14. The effect of TiO{sub 2} nanoparticles on water permeability and thermal and mechanical properties of high strength self-compacting concrete

    Energy Technology Data Exchange (ETDEWEB)

    Nazari, Ali, E-mail: alinazari84@aut.ac.ir [Department of Technical and Engineering Sciences, Islamic Azad University (Saveh Branch), Saveh (Iran, Islamic Republic of); Riahi, Shadi [Department of Technical and Engineering Sciences, Islamic Azad University (Saveh Branch), Saveh (Iran, Islamic Republic of)

    2010-12-15

    Research highlights: {yields} TiO{sub 2} nanoparticles effects on self-compacting concrete. {yields} Strength assessments. {yields} Water permeability. {yields} Thermal properties. {yields} Pore structure. {yields} Microstructure evaluations. - Abstract: In this work, strength assessments and coefficient of water absorption of high performance self-compacting concrete containing different amounts of TiO{sub 2} nanoparticles have been investigated. The results indicate that the strength and the resistance to water permeability of the specimens are improved by adding TiO{sub 2} nanoparticles in the cement paste up to 4.0 wt%. TiO{sub 2} nanoparticles, as a result of increased crystalline Ca(OH){sub 2} amount especially at the early age of hydration, could accelerate C-S-H gel formation and hence increase the strength of the concrete specimens. In addition, TiO{sub 2} nanoparticles are able to act as nanofillers and recover the pore structure of the specimens by decreasing harmful pores. Several empirical relationships have been presented to predict flexural and split tensile strength of the specimens by means of the corresponding compressive strength at a certain age of curing. Accelerated peak appearance in conduction calorimetry tests, more weight loss in thermogravimetric analysis and more rapid appearance of the peaks related to hydrated products in X-ray diffraction results, all indicate that TiO{sub 2} nanoparticles could improve mechanical and physical properties of the concrete specimens.

  15. The effect of TiO2 nanoparticles on water permeability and thermal and mechanical properties of high strength self-compacting concrete

    International Nuclear Information System (INIS)

    Nazari, Ali; Riahi, Shadi

    2010-01-01

    Research highlights: → TiO 2 nanoparticles effects on self-compacting concrete. → Strength assessments. → Water permeability. → Thermal properties. → Pore structure. → Microstructure evaluations. - Abstract: In this work, strength assessments and coefficient of water absorption of high performance self-compacting concrete containing different amounts of TiO 2 nanoparticles have been investigated. The results indicate that the strength and the resistance to water permeability of the specimens are improved by adding TiO 2 nanoparticles in the cement paste up to 4.0 wt%. TiO 2 nanoparticles, as a result of increased crystalline Ca(OH) 2 amount especially at the early age of hydration, could accelerate C-S-H gel formation and hence increase the strength of the concrete specimens. In addition, TiO 2 nanoparticles are able to act as nanofillers and recover the pore structure of the specimens by decreasing harmful pores. Several empirical relationships have been presented to predict flexural and split tensile strength of the specimens by means of the corresponding compressive strength at a certain age of curing. Accelerated peak appearance in conduction calorimetry tests, more weight loss in thermogravimetric analysis and more rapid appearance of the peaks related to hydrated products in X-ray diffraction results, all indicate that TiO 2 nanoparticles could improve mechanical and physical properties of the concrete specimens.

  16. Sterculia crosslinked PVA and PVA-poly(AAm) hydrogel wound dressings for slow drug delivery: mechanical, mucoadhesive, biocompatible and permeability properties.

    Science.gov (United States)

    Singh, Baljit; Pal, Lok

    2012-05-01

    The present study deals with the synthesis and characterization of sterculia crosslinked PVA and PVA-AAm hydrogel wound dressings. The hydrogels have been characterized by SEMs, FTIR, TGA and swelling studies. This article also discusses comparison of swelling, drug release and biomedical properties such as blood compatibility, antimicrobial activity, mucoadhesion, tensile strength, burst strength, water vapour permeability, oxygen diffusion and microbial penetration of both hydrogel wound dressings. These polymeric films have absorbed 4.80 ± 0.15 and 6.32 ± 0.15 gram/g of gel of simulated wound fluid respectively and swelling occurred through Case II diffusion mechanism. The release of antibiotic drugs occurred through non-Fickian and Case II diffusion mechanisms, respectively. These polymeric films have been observed to be permeable for oxygen and water vapour but have shown impermeability to the micro-organism. Sterculia-PVA hydrogel wound dressing has shown more blood compatibility as compared to the other film. All these results indicate that these hydrogel films may be used as wound dressings for the slow release of antibiotic drug to the wound. Copyright © 2012 Elsevier Ltd. All rights reserved.

  17. Compact rock material gas permeability properties

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Huanling, E-mail: whl_hm@163.com [Key Laboratory of Coastal Disaster and Defence, Ministry of Education, Hohai University, Nanjing 210098 (China); LML, University of Lille, Cite Scientifique, 59655 Villeneuve d’Ascq (France); Xu, Weiya; Zuo, Jing [Institutes of Geotechnical Engineering, Hohai University, Nanjing 210098 (China)

    2014-09-15

    Natural compact rocks, such as sandstone, granite, and rock salt, are the main materials and geological environment for storing underground oil, gas, CO{sub 2,} shale gas, and radioactive waste because they have extremely low permeabilities and high mechanical strengths. Using the inert gas argon as the fluid medium, the stress-dependent permeability and porosity of monzonitic granite and granite gneiss from an underground oil storage depot were measured using a permeability and porosity measurement system. Based on the test results, models for describing the relationships among the permeability, porosity, and confining pressure of rock specimens were analyzed and are discussed. A power law is suggested to describe the relationship between the stress-dependent porosity and permeability; for the monzonitic granite and granite gneiss (for monzonitic granite (A-2), the initial porosity is approximately 4.05%, and the permeability is approximately 10{sup −19} m{sup 2}; for the granite gneiss (B-2), the initial porosity is approximately 7.09%, the permeability is approximately 10{sup −17} m{sup 2}; and the porosity-sensitivity exponents that link porosity and permeability are 0.98 and 3.11, respectively). Compared with moderate-porosity and high-porosity rocks, for which φ > 15%, low-porosity rock permeability has a relatively lower sensitivity to stress, but the porosity is more sensitive to stress, and different types of rocks show similar trends. From the test results, it can be inferred that the test rock specimens’ permeability evolution is related to the relative particle movements and microcrack closure.

  18. Permeability and elastic properties of cracked glass under pressure

    Science.gov (United States)

    Ougier-Simonin, A.; GuéGuen, Y.; Fortin, J.; Schubnel, A.; Bouyer, F.

    2011-07-01

    Fluid flow in rocks is allowed through networks of cracks and fractures at all scales. In fact, cracks are of high importance in various applications ranging from rock elastic and transport properties to nuclear waste disposal. The present work aims at investigating thermomechanical cracking effects on elastic wave velocities, mechanical strength, and permeability of cracked glass under pressure. We performed the experiments on a triaxial cell at room temperature which allows for independent controls of the confining pressure, the axial stress, and pore pressure. We produced cracks in original borosilicate glass samples with a reproducible method (thermal treatment with a thermal shock of 300°C). The evolution of the elastic and transport properties have been monitored using elastic wave velocity sensors, strain gage, and flow measurements. The results obtained evidence for (1) a crack family with identified average aspect ratio and crack aperture, (2) a very small permeability which decreases as a power (exponential) function of pressure, and depends on (3) the crack aperture cube. We also show that permeability behavior of a cracked elastic brittle solid is reversible and independent of the fluid nature. Two independent methods (permeability and elastic wave velocity measurements) give these consistent results. This study provides data on the mechanical and transport properties of an almost ideal elastic brittle solid in which a crack population has been introduced. Comparisons with similar data on rocks allow for drawing interesting conclusions. Over the timescale of our experiments, our results do not provide any data on stress corrosion, which should be considered in further study.

  19. Incorporation of Sunflower Oil and d-alpha-tocopherol Effect on Mechanical Properties and Permeability of Corn Starch Composite Edible Film

    Directory of Open Access Journals (Sweden)

    Pramono Putro Utomo

    2015-06-01

    Full Text Available Corn starch-based films are inherently brittle and lack the necessary mechanical integrity for conventional packaging. However, the incorporation of additives can potentially improve the mechanical properties and processability of starch films. In this work sunflower oil (SO and vitamin E (d-alpha-tocopherol at three levels each (0.05%, 0.1% and 0.15% (w/vtotal and (0.18%, 0.36% and 0.54% (w/vtotal were incorporated into corn starch films using a solution casting method to improve the mechanical and water vapour transmission rate (WVTR properties. The addition of SO and vitamin E increased elongation at break of starch-based film while decreased tensile strength and WVTR of starch-based film. The best edible film obtained on addition of sunflower oil concentration of 0.15% and 0.54%, vitamin E with a value of 0.121 mm thickness, tensile strength of 65.38 kg/cm2, elongation at break 14.17% and WVTR 1144 g/m2 24 hours.

  20. The Mechanisms and Quantification of the Selective Permeability in Transport Across Biological Barriers : the Example of Kyotorphin

    NARCIS (Netherlands)

    Serrano, Isa D.; Freire, Joao M.; Carvalho, Miguel V.; Neves, Mafalda; Melo, Manuel N.; Castanho, Miguel A. R. B.

    2014-01-01

    This paper addresses the mechanisms behind selective endothelial permeability and their regulations. The singular properties of each of the seven blood-tissues barriers. Then, it further revisits the physical, quantitative meaning of permeability, and the way it should be measured based on sound

  1. Mechanisms of formation damage in matrix-permeability geothermal wells

    Energy Technology Data Exchange (ETDEWEB)

    Bergosh, J.L.; Wiggins, R.B.; Enniss, D.O.

    1982-04-01

    Tests were conducted to determine mechanisms of formation damage that can occur in matrix permeability geothermal wells. Two types of cores were used in the testing, actual cores from the East Mesa Well 78-30RD and cores from a fairly uniform generic sandstone formation. Three different types of tests were run. The East Mesa cores were used in the testing of the sensitivity of core to filtrate chemistry. The tests began with the cores exposed to simulated East Mesa brine and then different filtrates were introduced and the effects of the fluid contrast on core permeability were measured. The East Mesa cores were also used in the second series of tests which tested formation sandstone cores were used in the third test series which investigated the effects of different sizes of entrained particles in the fluid. Tests were run with both single-particle sizes and distributions of particle mixes. In addition to the testing, core preparation techniques for simulating fracture permeability were evaluated. Three different fracture formation mechanisms were identified and compared. Measurement techniques for measuring fracture size and permeability were also developed.

  2. Structure and properties of permeable fine-fibrous materials fabricated of powders

    Energy Technology Data Exchange (ETDEWEB)

    Fedorchenko, I M; Kostornov, A G; Kirichenko, O V; Guzhva, N S [AN Ukrainskoj SSR, Kiev. Inst. Problem Materialovedeniya

    1982-09-01

    Effect of main structural characteristics of fine fibrous materials (FFM) of nickel and Ni-Cr, Ni-Mo, Ni-Cr-Mo, Ni-Fe-Cr, Ni-Fe alloys on their hydraulic and mechanical properties was studied. FFM was produced by sintering of polymer fibers filled with metal powders and converted to felts. It was shown, that the level of permeable material properties increases with reduction of filament diameter.

  3. Structure and properties of permeable fine-fibrous materials fabricated of powders

    International Nuclear Information System (INIS)

    Fedorchenko, I.M.; Kostornov, A.G.; Kirichenko, O.V.; Guzhva, N.S.

    1982-01-01

    Effect of main structural characteristicf of fine fibrous materials (FFM) of nickel and Ni-Cr, Ni-Mo, Ni-Cr-Mo, Ni-Fe-Cr, Ni-Fe alloys on their hydraulic and mechanical properties was studied. FFM was produced by sintering of polymer fibers filled with metal powders and converted to felts. It was shown, that the level of permeable material properties increases with reduction of filament diameter

  4. Membrane properties for permeability testing: Skin versus synthetic membranes.

    Science.gov (United States)

    Haq, Anika; Dorrani, Mania; Goodyear, Benjamin; Joshi, Vivek; Michniak-Kohn, Bozena

    2018-03-25

    Synthetic membranes that are utilized in diffusion studies for topical and transdermal formulations are usually porous thin polymeric sheets for example cellulose acetate (CA) and polysulfones. In this study, the permeability of human skin was compared using two synthetic membranes: cellulose acetate and Strat-M® membrane and lipophilic and hydrophilic compounds either as saturated or formulated solutions as well as marketed dosage forms. Our data suggests that hydrophilic compounds have higher permeation in Strat-M membranes compared with lipophilic ones. High variation in permeability values, a typical property of biological membranes, was not observed with Strat-M. In addition, the permeability of Strat-M was closer to that of human skin than that of cellulose acetate (CA > Strat-M > Human skin). Our results suggest that Strat-M with little or no lot to lot variability can be applied in pilot studies of diffusion tests instead of human skin and is a better substitute than a cellulose acetate. Copyright © 2018 Elsevier B.V. All rights reserved.

  5. Characterizing gas permeability and pore properties of Czech granitic rocks

    Czech Academy of Sciences Publication Activity Database

    Konečný, Pavel; Kožušníková, Alena

    2016-01-01

    Roč. 13, č. 4 (2016), s. 331-338 ISSN 1214-9705 R&D Projects: GA ČR GA105/09/0089; GA MŠk(CZ) LO1406; GA MŠk ED2.1.00/03.0082 Institutional support: RVO:68145535 Keywords : granitic rocks * permeability * pore properties Subject RIV: DB - Geology ; Mineralogy Impact factor: 0.699, year: 2016 https://www.irsm.cas.cz/materialy/acta_content/2016_doi/Konecny_AGG_2016_0015.pdf

  6. Effect of preparation conditions on properties and permeability of chitosan-sodium hexametaphosphate capsules.

    Science.gov (United States)

    Angelova, N; Hunkeler, D

    2001-01-01

    Capsules were obtained by interpolymer complexation between chitosan (polycation) and sodium hexametaphosphate (SMP, oligoanion). The effect of the preparation conditions on the capsule characteristics was evaluated. Specifically, the influence of variables such as pH, ionic strength, reagent concentration, and additives on the capsule permeability properties was investigated using dextran as a model permeant. The capsule membrane permeability was found to increase by decreasing the chitosan/SMP ratio as well as adding mannitol to the oligoanion recipient bath. Increasing the ionic strength or the pH of the initial chitosan solution was also found to enhance the membrane permeability, moving the membrane exclusion limit to higher values. Generally, the capsules prepared tinder all tested conditions had a relatively low permeability which rarely exceeded a molecular cut-off of 40 kD based on dextran standards. Furthermore, the diffusion rate showed a strong temporal dependence, indicating that the capsules prepared under various conditions exhibit different apparent pore size densities on the surface. The results indicated that, in order to obtain the desired capsule mass-transfer properties, the preparation conditions should be carefully considered and adjusted. Adding a polyol as well as low salt amount (less than 0.15%) is preferable as a means of modulating the diffusion characteristics, without disturbing the capsule mechanical stability.

  7. Fabrication of porous Al-Cu sintered body and its permeability property

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Se-Hoon; Sung, Si-Young; Noh, Sang Ho; Kim, Sang Min [Korea Automotive Technology Institute, Cheonan (Korea, Republic of); Jin, Kwang Jin; Kim, Sang Min [Dongwon Technology Co., Kimhae (Korea, Republic of)

    2014-01-15

    In this study, porous Al-Cu sintered body was fabricated without any space-holder material and its properties, such as porosity, compressive yield strength, shore hardness, and permeability, were evaluated. Al-Cu powder mixtures were prepared by low-energy ball milling. The ball-milled powders were granulated and classified into size with <150 µm and 150-300 µm, and then they were compacted and sintered at 600 ℃ for 1 h in a vacuum and N{sub 2} atmosphere. The porosities of sintered bodies could be controlled in range of 15-48% by controlling the compaction pressure. The compressive yield strength and hardness were increased with a decreasing porosity. As a result, the mechanical properties and permeability of the optimized porous body were superior to that of commercial one.

  8. Preliminary study of soil permeability properties using principal component analysis

    Science.gov (United States)

    Yulianti, M.; Sudriani, Y.; Rustini, H. A.

    2018-02-01

    Soil permeability measurement is undoubtedly important in carrying out soil-water research such as rainfall-runoff modelling, irrigation water distribution systems, etc. It is also known that acquiring reliable soil permeability data is rather laborious, time-consuming, and costly. Therefore, it is desirable to develop the prediction model. Several studies of empirical equations for predicting permeability have been undertaken by many researchers. These studies derived the models from areas which soil characteristics are different from Indonesian soil, which suggest a possibility that these permeability models are site-specific. The purpose of this study is to identify which soil parameters correspond strongly to soil permeability and propose a preliminary model for permeability prediction. Principal component analysis (PCA) was applied to 16 parameters analysed from 37 sites consist of 91 samples obtained from Batanghari Watershed. Findings indicated five variables that have strong correlation with soil permeability, and we recommend a preliminary permeability model, which is potential for further development.

  9. Changes in permeability caused by transient stresses: field observations, experiments, and mechanisms

    Science.gov (United States)

    Manga, Michael; Beresnev, Igor; Brodsky, Emily E.; Elkhoury, Jean E.; Elsworth, Derek; Ingebritsen, Steve E.; Mays, David C.; Wang, Chi-Yuen

    2012-01-01

    Oscillations in stress, such as those created by earthquakes, can increase permeability and fluid mobility in geologic media. In natural systems, strain amplitudes as small as 10–6 can increase discharge in streams and springs, change the water level in wells, and enhance production from petroleum reservoirs. Enhanced permeability typically recovers to prestimulated values over a period of months to years. Mechanisms that can change permeability at such small stresses include unblocking pores, either by breaking up permeability-limiting colloidal deposits or by mobilizing droplets and bubbles trapped in pores by capillary forces. The recovery time over which permeability returns to the prestimulated value is governed by the time to reblock pores, or for geochemical processes to seal pores. Monitoring permeability in geothermal systems where there is abundant seismicity, and the response of flow to local and regional earthquakes, would help test some of the proposed mechanisms and identify controls on permeability and its evolution.

  10. Drug-like properties and the causes of poor solubility and poor permeability.

    Science.gov (United States)

    Lipinski, C A

    2000-01-01

    There are currently about 10000 drug-like compounds. These are sparsely, rather than uniformly, distributed through chemistry space. True diversity does not exist in experimental combinatorial chemistry screening libraries. Absorption, distribution, metabolism, and excretion (ADME) and chemical reactivity-related toxicity is low, while biological receptor activity is higher dimensional in chemistry space, and this is partly explainable by evolutionary pressures on ADME to deal with endobiotics and exobiotics. ADME is hard to predict for large data sets because current ADME experimental screens are multi-mechanisms, and predictions get worse as more data accumulates. Currently, screening for biological receptor activity precedes or is concurrent with screening for properties related to "drugability." In the future, "drugability" screening may precede biological receptor activity screening. The level of permeability or solubility needed for oral absorption is related to potency. The relative importance of poor solubility and poor permeability towards the problem of poor oral absorption depends on the research approach used for lead generation. A "rational drug design" approach as exemplified by Merck advanced clinical candidates leads to time-dependent higher molecular weight, higher H-bonding properties, unchanged lipophilicity, and, hence, poorer permeability. A high throughput screening (HTS)-based approach as exemplified by unpublished data on Pfizer (Groton, CT) early candidates leads to higher molecular weight, unchanged H-bonding properties, higher lipophilicity, and, hence, poorer aqueous solubility.

  11. Optic Nerve Sheath Mechanics and Permeability in VIIP Syndrome

    Science.gov (United States)

    Raykin, Julia; Best, Lauren; Gleason, Rudy; Mulugeta, Lealem; Myers, Jerry; Nelson, Emily; Samuels, Brian C.; Ethier, C. R.

    2014-01-01

    Long-duration space flight carries the risk of developing Visual Impairment and Intracranial Pressure (VIIP) syndrome, a spectrum of ophthalmic changes including posterior globe flattening, choroidal folds, distension of the optic nerve sheath (ONS), optic nerve kinking and potentially permanent degradation of visual function. The slow onset of VIIP, its chronic nature, and certain clinical features strongly suggest that biomechanical factors acting on the ONS play a role in VIIP. Here we measure several relevant ONS properties needed to model VIIP biomechanics. The ONS (meninges) of fresh porcine eyes (n7) was reflected, the nerve proper was truncated near the sclera, and the meninges were repositioned to create a hollow cylinder of meningeal connective tissue attached to the posterior sclera. The distal end was cannulated, sealed, and pressure clamped (mimicking cerebrospinal fluid [CSF] pressure), while the eye was also cannulated for independent control of intraocular pressure (IOP). The meninges were inflated (CSF pressure cycling 7-50 mmHg) while ONS outer diameter was imaged. In another set of experiments (n4), fluid permeation rate across the meninges was recorded by observing the drainage of an elevated fluid reservoir (30 mmHg) connected to the meninges. The ONS showed behavior typical of soft tissues: viscoelasticity, with hysteresis in early preconditioning cycles and repeatable behavior after 4 cycles, and nonlinear stiffening, particularly at CSF pressures 15 mmHg (Figure). Tangent moduli measured from the loading curve were 372 101, 1199 358, and 2050 379 kPa (mean SEM) at CSF pressures of 7, 15 and 30 mmHg, respectively. Flow rate measurements through the intact meninges at 30mmHg gave a permeability of 1.34 0.46 lmincm2mmHg (mean SEM). The ONS is a tough, strain-stiffening connective tissue that is surprisingly permeable. The latter observation suggests that there could be significant CSF drainage through the ONS into the orbit, likely important

  12. Cross-property relations and permeability estimation in model porous media

    International Nuclear Information System (INIS)

    Schwartz, L.M.; Martys, N.; Bentz, D.P.; Garboczi, E.J.; Torquato, S.

    1993-01-01

    Results from a numerical study examining cross-property relations linking fluid permeability to diffusive and electrical properties are presented. Numerical solutions of the Stokes equations in three-dimensional consolidated granular packings are employed to provide a basis of comparison between different permeability estimates. Estimates based on the Λ parameter (a length derived from electrical conduction) and on d c (a length derived from immiscible displacement) are found to be considerably more reliable than estimates based on rigorous permeability bounds related to pore space diffusion. We propose two hybrid relations based on diffusion which provide more accurate estimates than either of the rigorous permeability bounds

  13. Mechanical and transport properties of rocks at high temperatures and pressures. Task II. Fracture permeability of crystalline rocks as a function of temperature, pressure, and hydrothermal alteration. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Johnson, B.

    1985-11-01

    Pore-fluid chemical interactions on both short and long time scales can significantly change the permeability of a rock. Measurement of the permeability variations requires adaption and modification on standard measurement systems, with special attention given to pore-fluid flow rates and metal corrosion of system components. In this report, system requirements and capabilities are reviewed, analyzed, and recommendations made. Special attention is given to the choice of corrosion resistant metals, fluid-flow systems, back-pressure systems, jacketing materials, and flow-rate measurement. On the basis of this study, an economical, highly flexible, permeability system was designed and built. The system allows measurement of permeability over the darcy to nanodarcy range, using geologically meaningful, chemically reactive, pore fluids under constant volume flow rates as small as 0.2 ml/day at temperatures in excess of 300C, fluid pressures to 20 MPa, and confining pressures to 100 MPa. 7 refs., 3 figs., 1 tab.

  14. Dynamic mechanical properties of buffer material

    International Nuclear Information System (INIS)

    Takaji, Kazuhiko; Taniguchi, Wataru

    1999-11-01

    The buffer material is expected to maintain its low water permeability, self-sealing properties, radionuclides adsorption and retardation properties, thermal conductivity, chemical buffering properties, overpack supporting properties, stress buffering properties, etc. over a long period of time. Natural clay is mentioned as a material that can relatively satisfy above. Among the kinds of natural clay, bentonite when compacted is superior because (i) it has exceptionally low water permeability and properties to control the movement of water in buffer, (ii) it fills void spaces in the buffer and fractures in the host rock as it swells upon water uptake, (iii) it has the ability to exchange cations and to adsorb cationic radioelements. In order to confirm these functions for the purpose of safety assessment, it is necessary to evaluate buffer properties through laboratory tests and engineering-scale tests, and to make assessments based on the ranges in the data obtained. This report describes the procedures, test conditions, results and examinations on the buffer material of dynamic triaxial tests, measurement of elastic wave velocity and liquefaction tests that aim at getting hold of dynamic mechanical properties. We can get hold of dependency on the shearing strain of the shearing modulus and hysteresis damping constant, the application for the mechanical model etc. by dynamic triaxial tests, the acceptability of maximum shearing modulus obtained from dynamic triaxial tests etc. by measurement of elastic wave velocity and dynamic strength caused by cyclic stress etc. by liquefaction tests. (author)

  15. Effects of temperature, mechanical loading and of their interactions on the permeability of structural concrete

    International Nuclear Information System (INIS)

    Choinska, M.

    2006-11-01

    Concrete permeability may influence the durability of structures indirectly by controlling the penetration rate of aggressive agents, but also directly if the structure has a confinement role, like containment vessels of nuclear power plants for instance. In the industrial background on the safety of these structures, the objective of this study is to characterize the evolution of concrete permeability under the effects of temperature and mechanical loading. The permeability tests are performed on hollow concrete cylinders, subjected to temperature up to 150 C and compressive loading up to failure. Experimental results reveal that the effects of temperature and damage may be decoupled for the estimation of permeability and enable us to propose a relation between permeability, damage and temperature. However, this relation may only be applied in the pre-peak phase as concrete remains micro-cracked. In order to overcome this limit to be able to model also permeability increase in the post-peak phase, another parameter, which is crack opening, is introduced in the relation between permeability and damage. This problem, investigated by modelling, is exploited according to two approaches. The first one is based on the definition of a matching law between existing relations of permeability evolution with damage and with crack opening. With this approach the tendencies are similar to the observed ones on the experimental results. The second approach consists in linking from a mechanical point of view damage with crack opening in order to apply the Poiseuille's law for permeability determination. Experimental validation of this approach, emerging towards a continuous model capable to reproduce permeability variations of a concrete structure, constitutes a major perspective of this work. (author)

  16. Emergent properties of patch shapes affect edge permeability to animals.

    Directory of Open Access Journals (Sweden)

    Vilis O Nams

    Full Text Available Animal travel between habitat patches affects populations, communities and ecosystems. There are three levels of organization of edge properties, and each of these can affect animals. At the lowest level are the different habitats on each side of an edge, then there is the edge itself, and finally, at the highest level of organization, is the geometry or structure of the edge. This study used computer simulations to (1 find out whether effects of edge shapes on animal behavior can arise as emergent properties solely due to reactions to edges in general, without the animals reacting to the shapes of the edges, and to (2 generate predictions to allow field and experimental studies to test mechanisms of edge shape response. Individual animals were modeled traveling inside a habitat patch that had different kinds of edge shapes (convex, concave and straight. When animals responded edges of patches, this created an emergent property of responding to the shape of the edge. The response was mostly to absolute width of the shapes, and not the narrowness of them. When animals were attracted to edges, then they tended to collect in convexities and disperse from concavities, and the opposite happened when animals avoided edges. Most of the responses occurred within a distance of 40% of the perceptual range from the tip of the shapes. Predictions were produced for directionality at various locations and combinations of treatments, to be used for testing edge behavior mechanisms. These results suggest that edge shapes tend to either concentrate or disperse animals, simply because the animals are either attracted to or avoid edges, with an effect as great as 3 times the normal density. Thus edge shape could affect processes like pollination, seed predation and dispersal and predator abundance.

  17. Relationship between micro-porosity, water permeability and mechanical behavior in scaffolds for cartilage engineering.

    Science.gov (United States)

    Vikingsson, L; Claessens, B; Gómez-Tejedor, J A; Gallego Ferrer, G; Gómez Ribelles, J L

    2015-08-01

    In tissue engineering the design and optimization of biodegradable polymeric scaffolds with a 3D-structure is an important field. The porous scaffold provide the cells with an adequate biomechanical environment that allows mechanotransduction signals for cell differentiation and the scaffolds also protect the cells from initial compressive loading. The scaffold have interconnected macro-pores that host the cells and newly formed tissue, while the pore walls should be micro-porous to transport nutrients and waste products. Polycaprolactone (PCL) scaffolds with a double micro- and macro-pore architecture have been proposed for cartilage regeneration. This work explores the influence of the micro-porosity of the pore walls on water permeability and scaffold compliance. A Poly(Vinyl Alcohol) with tailored mechanical properties has been used to simulate the growing cartilage tissue inside the scaffold pores. Unconfined and confined compression tests were performed to characterize both the water permeability and the mechanical response of scaffolds with varying size of micro-porosity while volume fraction of the macro-pores remains constant. The stress relaxation tests show that the stress response of the scaffold/hydrogel construct is a synergic effect determined by the performance of the both components. This is interesting since it suggests that the in vivo outcome of the scaffold is not only dependent upon the material architecture but also the growing tissue inside the scaffold׳s pores. On the other hand, confined compression results show that compliance of the scaffold is mainly controlled by the micro-porosity of the scaffold and less by hydrogel density in the scaffold pores. These conclusions bring together valuable information for customizing the optimal scaffold and to predict the in vivo mechanical behavior. Copyright © 2015 Elsevier Ltd. All rights reserved.

  18. Increased gut permeability in cancer cachexia: mechanisms and clinical relevance.

    Science.gov (United States)

    Bindels, Laure B; Neyrinck, Audrey M; Loumaye, Audrey; Catry, Emilie; Walgrave, Hannah; Cherbuy, Claire; Leclercq, Sophie; Van Hul, Matthias; Plovier, Hubert; Pachikian, Barbara; Bermúdez-Humarán, Luis G; Langella, Philippe; Cani, Patrice D; Thissen, Jean-Paul; Delzenne, Nathalie M

    2018-04-06

    Intestinal disorders often occur in cancer patients, in association with body weight loss, and this alteration is commonly attributed to the chemotherapy. Here, using a mouse model of cancer cachexia induced by ectopic transplantation of C26 cancer cells, we discovered a profound alteration in the gut functions (gut permeability, epithelial turnover, gut immunity, microbial dysbiosis) independently of any chemotherapy. These alterations occurred independently of anorexia and were driven by interleukin 6. Gut dysfunction was found to be resistant to treatments with an anti-inflammatory bacterium ( Faecalibacterium prausnitzii ) or with gut peptides involved in intestinal cell renewal (teduglutide, a glucagon-like peptide 2 analogue). The translational value of our findings was evaluated in 152 colorectal and lung cancer patients with or without cachexia. The serum level of the lipopolysaccharide-binding protein, often presented as a reflection of the bacterial antigen load, was not only increased in cachectic mice and cancer patients, but also strongly correlated with the serum IL-6 level and predictive of death and cachexia occurrence in these patients. Altogether, our data highlight profound alterations of the intestinal homeostasis in cancer cachexia occurring independently of any chemotherapy and food intake reduction, with potential relevance in humans. In addition, we point out the lipopolysaccharide-binding protein as a new biomarker of cancer cachexia related to gut dysbiosis.

  19. Elastic and electrical properties and permeability of serpentinites from Atlantis Massif, Mid-Atlantic Ridge

    Science.gov (United States)

    Falcon-Suarez, Ismael; Bayrakci, Gaye; Minshull, Tim A.; North, Laurence J.; Best, Angus I.; Rouméjon, Stéphane

    2017-11-01

    Serpentinized peridotites co-exist with mafic rocks in a variety of marine environments including subduction zones, continental rifts and mid-ocean ridges. Remote geophysical methods are crucial to distinguish between them and improve the understanding of the tectonic, magmatic and metamorphic history of the oceanic crust. But, serpentinite peridotites exhibit a wide range of physical properties that complicate such a distinction. We analysed the ultrasonic P- and S-wave velocities (Vp, Vs) and their respective attenuation (Qp-1, Qs-1), electrical resistivity and permeability of four serpentinized peridotite samples from the southern wall of the Atlantis Massif, Mid-Atlantic Ridge, collected during International Ocean Discovery Program Expedition 357. The measurements were taken over a range of loading-unloading stress paths (5-45 MPa), using ∼1.7 cm length, 5 cm diameter samples horizontally extracted from the original cores drilled on the seafloor. The measured parameters showed variable degrees of stress dependence, but followed similar trends. Vp, Vs, resistivity and permeability show good inter-correlations, while relationships that included Qp-1 and Qs-1 are less clear. Resistivity showed high contrast between highly serpentinized ultramafic matrix (>50 Ω m) and mechanically/geochemically altered (magmatic/hydrothermal-driven alteration) domains (serpentinization and the alteration state of the rock, contrasted by petrographic analysis. This study shows the potential of combining seismic techniques and controlled source electromagnetic surveys for understanding tectonomagmatic processes and fluid pathways in hydrothermal systems.

  20. Cage and linear structured polysiloxane/epoxy hybrids for coatings: Surface property and film permeability.

    Science.gov (United States)

    Ma, Yanli; He, Ling; Jia, Mengjun; Zhao, Lingru; Zuo, Yanyan; Hu, Pingan

    2017-08-15

    Three polysiloxane/epoxy hybrids obtained by evolving cage- or linear-structured polysiloxane into poly glycidyl methacrylate (PGMA) matrix are compared used as coatings. One is the cage-structured hybrid of P(GMA/MA-POSS) copolymer obtained by GMA and methacrylisobutyl polyhedral oligomeric silsesquioxane (MA-POSS) via free radical polymerization, the other two are PGMA/NH 2 -POSS and PGMA/NH 2 -PDMS hybrids by cage-structured aminopropyllsobutyl POSS (NH 2 -POSS) or linear-structured diamino terminated poly(dimethylsiloxane) (NH 2 -PDMS) to cure PGMA. The effect of MA-POSS, NH 2 -POSS and NH 2 -PDMS on polysiloxane/epoxy hybrid films is characterized according to their surface morphology, transparency, permeability, adhesive strength and thermo-mechanical properties. Due to caged POSS tending to agglomerate onto the film surface, P(GMA/MA-POSS) and PGMA/NH 2 -POSS films exhibit much more heterogeneous surfaces than PGMA/NH 2 -PDMS film, but the well-compatibility between epoxy matrix and MA-POSS has provided P(GMA/MA-POSS) film with much higher transmittance (98%) than PGMA/NH 2 -POSS film (24%), PGMA/NH 2 -PDMS film (27%) and traditional epoxy resin film (5%). The introduction of polysiloxane into epoxy matrix is confirmed to create hybrids with strong adhesive strength (526-1113N) and high thermos-stability (T g =262-282°C), especially the cage-structured P(GMA/MA-POSS) hybrid (1113N and 282°C), but the flexible PDMS improves PGMA/NH 2 -PDMS hybrid with much higher storage modulus (519MPa) than PGMA/NH 2 -POSS (271MPa), which suggests that PDMS is advantage in improving the film stiffness than POSS cages. However, cage-structured P(GMA/MA-POSS) and PGMA/NH 2 -POSS indicate higher permeability than PGMA/NH 2 -PDMS and traditional epoxy resin. Comparatively, the cage-structured P(GMA/MA-POSS) hybrid is the best coating in transparency, permeability, adhesive strength and thermostability, but linear-structured PGMA/NH 2 -PDMS hybrid behaviors the best coating in

  1. 煤岩组合体力学特性与瓦斯渗流规律试验研究%Experimental Study on Mechanical Properties and Permeability Evolution Law of Coal-rock Combination

    Institute of Scientific and Technical Information of China (English)

    常悦; 张雅萍; 栗继祖; 王向玲; 马利云; 李燕

    2017-01-01

    Based on triaxial permeability test system,the strength characteristics and permeability evolution law of coal-rock specimens of different height ratios of rock to coal under the condition of simulating different thicknesses of roof-coal-floor are studied.The results show that the peak strength values for coal-rock specimens are different due to the different height ratios of rock to coal,and the peak stress increases with the height ratio.The broken and failure models of the coal-rock combination specimens show a macroscopic shear fracture surface,and the fracture surface runs through the top and bottom rocks.With the increase of the axial strain,the permeability evolution law of the coal-rock combination specimen shows the "V" shape,which decreases to the lowest point first and then increases rapidly.And the corresponding axial strain of the permeability curve increases with the increase of the height ratio of rock to coal.%利用三轴渗流测试系统,模拟不同厚度的顶板、煤层和底板条件,进行了不同岩煤高度比条件下煤岩组合试件的力学特性与渗流规律的试验研究.结果表明:对于不同岩煤高度比的煤岩组合试件,失稳破坏的峰值强度存在差异,且峰值强度随岩煤高度比的增加呈增大趋势;组合煤岩体的失稳破坏呈现宏观剪切破裂面,且破裂面贯穿顶、底部岩石;组合煤岩体的渗透率随轴向应变的升高呈现先减小到最小值后迅速增加的“V”型变化趋势;且随着岩煤高度比的增加,渗透率曲线反弹点对应的轴向应变呈增大趋势.

  2. Mechanical properties of papercrete

    Directory of Open Access Journals (Sweden)

    Zaki Harith

    2018-01-01

    Full Text Available This paper studies the uses, of waste paper as an additional material in concrete mixes. Papercrete is a term as the name seems, to imply a mixture of paper and concrete. It is a new, composite material using waste paper, as a partial addition of Portland cement, and is a sustainable, building material due to, reduced amount of waste paper being put to use. It gains, latent strength due to presence of hydrogen bonds in microstructure of paper. Papercrete has been, reported to be a low cost alternative, building construction, material and has, good sound absorption, and thermal insulation; to be a lightweight and fire-resistant material. The percent of waste paper used (after treating namely (5%, 10%, 15% and 20% by weight of cement to explore the mechanical properties of the mixes (compressive strength, splitting tensile strength, flexural strength, density, as compared with references mixes, it was found that fresh properties affected significantly by increasing the waste paper content. The compressive strength, splitting tensile strength, flexural strength and density got decreased with increase in the percentage of paper.

  3. Testing the permeability and corrosion resistance of micro-mechanically interlocked joints

    DEFF Research Database (Denmark)

    Byskov-Nielsen, Jeppe; Holm, Allan Hjarbæk; Højsholt, Rune

    2011-01-01

    Micro-mechanical interlocking (MMI) can be applied to create new and interesting composite materials. We have employed laser structuring to achieve MMI between stainless steel and plastic with extremely high joint strength. However, the water permeability and corrosion resistance of the joint must...... is conducted. The permeability seems to be consistent with the Hagen–Poiseuille equation independent of the laser structuring technique and is orders of magnitudes larger than the diffusion rate through the plastic. Two different types of corrosion tests have been undertaken, and we show that care must...... be taken in order not to degrade the corrosion resistance of the sample to an unacceptable level....

  4. Prediction of the permeability of neutral drugs inferred from their solvation properties

    KAUST Repository

    Milanetti, Edoardo; Raimondo, Domenico; Tramontano, Anna

    2015-01-01

    Results: The method has been tested on twenty-three neutral drugs for which a consistent set of experimental data is available. We show here that our method reproduces the experimental data better than other existing tools. Furthermore it provides a detailed view of the relationship between the hydration and the permeability properties of molecules.

  5. WATER VAPOUR PERMEABILITY PROPERTIES OF CELLULAR WOOD MATERIAL AND CONDENSATION RISK OF COMPOSITE PANEL WALLS

    Directory of Open Access Journals (Sweden)

    Janis IEJAVS

    2016-09-01

    Full Text Available Invention of light weight cellular wood material (CWM with a trade mark of Dendrolight is one of innovations in wood industry of the last decade. The aim of the research was to define the water vapour permeability properties of CWM and to analyse the condensation risk of various wall envelopes where solid wood cellular material is used. To determine the water vapour permeability of CWM, test samples were produced in the factory using routine production technology and tested according to the standard EN 12086:2014. Water vapour permeability factor (μ and other properties of six different configurations of CWM samples were determined. Using the experimental data the indicative influence of geometrical parameters such as lamella thickness, number of lamellas and material direction were investigated and evaluated. To study the condensation risk within the wall envelope containing CWM calculation method given in LVS EN ISO 13788:2012 was used. To ease the calculation process previously developed JavaScript calculation software that had only capability to calculate thermal transmittance was extended so that condensation risk in multi-layer composite walls can be analysed. Water vapour permeability factor in CWM is highly direction dependant. If parallel and perpendicular direction of CWM is compared the value of water vapour permeability factor can differentiate more than two times. Another significant factor for condensation risk analysis is overall thickness of CWM since it directly influences the equivalent air layer thickness. The influence of other factors such as lamella thickness, or groove depth is minor when water vapour permeability properties are compared. From the analysis of CWM performance in building envelope it can be concluded that uninsulated CWM panels used during winter months will pose the risk of condensation damage to structure, but the risk can be reduced or prevented if insulation layer is applied to the CWM panel wall

  6. Static mechanical properties of buffer material

    International Nuclear Information System (INIS)

    Takaji, Kazuhiko; Suzuki, Hideaki

    1999-11-01

    The buffer material is expected to maintain its low water permeability, self-sealing properties, radionuclides adsorption and retardation properties, thermal conductivity, chemical buffering properties, overpack supporting properties, stress buffering properties, etc. over a long period of time. Natural clay is mentioned as a material that can relatively satisfy above. Among the kinds of natural clay, bentonite when compacted is superior because (i) it has exceptionally low water permeability and properties to control the movement of water in buffer, (ii) it fills void spaces in the buffer and fractures in the host rock as it swells upon water uptake, (iii) it has the ability to exchange cations and to adsorb cationic radioelements. In order to confirm these functions for the purpose of safety assessment, it is necessary to evaluate buffer properties through laboratory tests and engineering-scale tests, and to make assessments based on the ranges in the data obtained. This report describes the procedures, test conditions, results and examinations on the buffer material of unconfined compression tests, one-dimensional consolidation tests, consolidated-undrained triaxial compression tests and consolidated-undrained triaxial creep tests that aim at getting hold of static mechanical properties. We can get hold of the relationship between the dry density and tensile stress etc. by Brazilian tests, between the dry density and unconfined compressive strength etc. by unconfined compression tests, between the consolidation stress and void ratio etc. by one-dimensional consolidation tests, the stress pass of each effective confining pressure etc. by consolidated-undrained triaxial compression tests and the axial strain rate with time of each axial stress etc. by consolidated-undrained triaxial creep tests. (author)

  7. Mechanical properties of ceramics

    CERN Document Server

    Pelleg, Joshua

    2014-01-01

    This book discusses the mechanical properties of ceramics and aims to provide both a solid background for undergraduate students, as well as serving as a text to bring practicing engineers up to date with the latest developments in this topic so they can use and apply these to their actual engineering work.  Generally, ceramics are made by moistening a mixture of clays, casting it into desired shapes and then firing it to a high temperature, a process known as 'vitrification'. The relatively late development of metallurgy was contingent on the availability of ceramics and the know-how to mold them into the appropriate forms. Because of the characteristics of ceramics, they offer great advantages over metals in specific applications in which hardness, wear resistance and chemical stability at high temperatures are essential. Clearly, modern ceramics manufacturing has come a long way from the early clay-processing fabrication method, and the last two decades have seen the development of sophisticated technique...

  8. Crack modelling for the assessment of stiffness loss of reinforced concrete structures under mechanical loading - determination of the permeability of the micro-cracked body

    International Nuclear Information System (INIS)

    Bongue Boma, M.

    2007-12-01

    We propose a model describing the evolution of mechanical and permeability properties of concrete under slow mechanical loading. Calling upon the theory of continua with microstructure, the kinematic of the domain is enriched by a variable characterising size and orientation of the crack field. We call upon configurational forces to deal with crack propagation and we determine the balance equations governing both strain and propagation. The geometry of the microstructure is representative of the porous media: the permeability is obtained from the resolution of Stokes equations in an elementary volume. An example has been treated: we considered simple assumptions (uniform crack field, application of linear fracture mechanics...) and we determined the behaviour of a body under tensile loading. Strain, crack propagation and stiffness loss are completely assessed. Finally the evolution of permeability is plotted: once activated, crack propagation is the main cause of water tightness loss. (author)

  9. A biodegradable polymer nanocomposite: Mechanical and barrier properties

    Science.gov (United States)

    Lilichenko, N.; Maksimov, R. D.; Zicans, J.; Merijs Meri, R.; Plume, E.

    2008-01-01

    The preparation of an environmentally friendly nanocomposite based on plasticized potato starch and unmodified montmorillonite clay is described. Data on the influence of montmorillonite concentration on the mechanical properties of the materials obtained are reported. The effective elastic constants of the nanocomposites are calculated. The calculation results are compared with experimental data. The influence of montmorillonite content on the moisture permeability is also investigated.

  10. Mechanical properties of clayey soils and thermal solicitations

    International Nuclear Information System (INIS)

    Boisson, J.Y.

    1992-01-01

    Changes in permeability and mechanical properties of three clayey soils with temperature have been studied by using a special oedometric cell. The action of a thermal solicitation on the fabric and the behavior of the samples is highlighted. 3 figs., 1 tab

  11. Characterization of the mechanical and hydraulic damage in the excavation damaged zone of MHM with gas permeability measurement

    International Nuclear Information System (INIS)

    Yang, D.

    2008-09-01

    On the feasibility evaluation of nuclear waste storage in deep formations, the essential issues are as follows: the stability of underground structures over the reversible period, the influence of cavity excavation on geomechanical properties of the wall rock and the variation of those properties during the different phases while storage realization. The work presented here covers the investigations on the variation of geomechanical properties of the approximately 500 m deep MHM in France (mudstone in the departments of Meuse/Haute-Marne), chosen as a potential medium for nuclear waste disposal by ANDRA. In order to measure the very low permeability of mudstone and to observe the dependency on saturation, a special test scheme on measurement of gas permeability has been developed. In the scheme, in situ referenced stresses have been chosen as the stresses acting on the solid matrix. The gas permeability has been determined with both analytical and numerical methods. To estimate the mechanical damage of storage induced by the excavation, laboratory tests on gas permeability have been conducted on samples recovered from different locations situated at different distances from the wall of the main access shaft of the MHM (from 0,1 m to 12,5 m). Results of gas permeability obtained under an isotropic stress of 11 MPa vary between 10 -21 and 10 -22 m 2 and do not show significant variations between damaged zones (near the wall) and intact zones (sample located 12 m from the wall). The observations in laboratory tests coincide with in situ damage characterizations. The variation of gas permeability under the cycle of loading and unloading is an order less than the initial value under the isotropic stress. Taking into account the precision of the testing system, this variation is not significant. The oviparous intact samples have been imposed different saturations by salt solutions (with a relative humidity from 25 % to 98 %) to form a cycle of de- and re-saturation. The

  12. Physicochemical Properties, Permeability and Bioavailability of Geraniin and Geraniin-Phospholipid Complex

    OpenAIRE

    SUMITA ELENDRAN

    2017-01-01

    Geraniin has been credited with a range of bioactive properties and therefore merits greater research into its potential pharmaceutical, nutraceutical and cosmetic applications. To clarify its functionalities and to explore future applications, a more comprehensive understanding of geraniin; its physiochemical, permeability, bioavailability and pharmacokinetic properties has become necessity. In light of geraniin’s anticipated poor bioavailability and to be considered as an oral drug candidat...

  13. Effect of a mechanical damage on permeability and moisture diffusivity of concrete

    International Nuclear Information System (INIS)

    Picandet, V.

    2001-12-01

    The effect of a mechanical damage on transfer parameters of concrete is an original point of view on the coupling between damage and durability. The studied transfer parameters, permeability and moisture diffusivity, allow to characterize the transport ability of a porous media to convey gases or water (liquid and vapour). The theoretical framework of the measurement of these parameters and its applications to concrete is pointed out. The experimental studies are carried on three types of concrete: ordinary concrete, high performance concrete, and high performance steel fiber reinforced concrete. Two kinds of damage are considered and generated in samples: - A continuous damage of the medium, obtained by cyclic uniaxial loading. It is characterized by a loss of stiffness and results in a diffuse microcracking.- A discrete or localised damage, obtained by a diametrical compression of cylindrical specimens. It is characterized by the presence of identifiable and measurable cracks. Measurements of gas permeability are taken using a constant head, Cembureau type, permeameter. For cracked samples, the procedure and analysis of the results are changed in order to make the evaluation of their gas and water permeability. The simple imbibition and positive head imbibition are the disturbances of the moisture equilibrium, which allow the evaluation of the material diffusivity. The local moisture contents of the specimen are measured using a gamma-ray attenuation method. The analysis of profiles using Boltzmann's transformation leads to the moisture diffusivity and then to the water permeability coefficients. Measurements of gas and water permeability are compared in both cases of considered damage. In the first case, a damage - permeability relationship dependent on the fluid of percolation but valid for all concrete types studied could be worked out. (author)

  14. Estimating saturated hydraulic conductivity and air permeability from soil physical properties using state-space analysis

    DEFF Research Database (Denmark)

    Poulsen, Tjalfe; Møldrup, Per; Nielsen, Don

    2003-01-01

    and gaseous chemicals in the vadose zone. In this study, three modeling approaches were used to identify the dependence of saturated hydraulic conductivity (K-S) and air permeability at -100 cm H2O soil-water potential (k(a100)) on soil physical properties in undisturbed soil: (i) Multiple regression, (ii......) ARIMA (autoregressive integrated moving average) modeling, and (iii) State-space modeling. In addition to actual soil property values, ARIMA and state-space models account for effects of spatial correlation in soil properties. Measured data along two 70-m-long transects at a 20-year old constructed......Estimates of soil hydraulic conductivity (K) and air permeability (k(a)) at given soil-water potentials are often used as reference points in constitutive models for K and k(a) as functions of moisture content and are, therefore, a prerequisite for predicting migration of water, air, and dissolved...

  15. Crustal permeability

    Science.gov (United States)

    Gleeson, Tom; Ingebritsen, Steven E.

    2016-01-01

    Permeability is the primary control on fluid flow in the Earth’s crust and is key to a surprisingly wide range of geological processes, because it controls the advection of heat and solutes and the generation of anomalous pore pressures.  The practical importance of permeability – and the potential for large, dynamic changes in permeability – is highlighted by ongoing issues associated with hydraulic fracturing for hydrocarbon production (“fracking”), enhanced geothermal systems, and geologic carbon sequestration.  Although there are thousands of research papers on crustal permeability, this is the first book-length treatment.  This book bridges the historical dichotomy between the hydrogeologic perspective of permeability as a static material property and the perspective of other Earth scientists who have long recognized permeability as a dynamic parameter that changes in response to tectonism, fluid production, and geochemical reactions. 

  16. Water sorption and water permeability properties of edible film made from potato peel waste

    Directory of Open Access Journals (Sweden)

    Siti Hajar OTHMAN

    Full Text Available Abstract The water sorption and permeability properties of edible film produced from potato peel waste was investigated under different levels of relative humidity (23, 33, 43, 57, 75% RH and temperatures (5, 30, 50 °C. The water sorption behaviour and isotherms of the film were investigated by fitting water sorption data to the Peleg model and the Guggenheim, Anderson de Boer model (GAB model. The amount of moisture content, time required for the moisture content of the film to reach equilibrium, water sorption rate, and water sorption capacity increased when the relative humidity increased. The effect of temperature on moisture content, water sorption rate, water sorption capacity, and monolayer moisture content is complex and related to the water activity as well as the moisture content. Based on R2 and RMSE values, the Peleg and GAB models were respectively determined as excellent models to predict the water sorption properties of the films, thus supporting the reliability of water sorption behaviour prediction. The water vapour transmission rate and water vapour permeability increased with an increase in relative humidity and temperature. The sorption and permeability properties of the film are worth investigation since the final application of the film as food packaging is ultimately dependent on these behaviours.

  17. Blood-brain barrier permeability and brain uptake mechanism of kainic Acid and dihydrokainic Acid

    DEFF Research Database (Denmark)

    Gynther, Mikko; Petsalo, Aleksanteri; Hansen, Steen Honoré

    2015-01-01

    tools in various in vivo central nervous system disease models in rodents, as well as being templates in the design of novel ligands affecting the glutamatergic system. Both molecules are highly polar but yet capable of crossing the blood-brain barrier (BBB). We used an in situ rat brain perfusion...... technique to determine the brain uptake mechanism and permeability across the BBB. To determine KA and DHK concentrations in the rat brain, simple and rapid sample preparation and liquid chromatography mass spectrometer methods were developed. According to our results the BBB permeability of KA and DHK...... is low, 0.25 × 10(-6) and 0.28 × 10(-6) cm/s for KA and DHK, respectively. In addition, the brain uptake is mediated by passive diffusion, and not by active transport. Furthermore, the non-specific plasma and brain protein binding of KA and DHK was determined to be low, which means that the unbound drug...

  18. Experimental Study of Bacterial Penetration into Chalk Rock: Mechanisms and Effect on Permeability

    DEFF Research Database (Denmark)

    Halim, Amalia Yunita; Shapiro, Alexander; Eliasson Lantz, Anna

    2014-01-01

    Bacterial selective plugging is one of the mechanisms through which microorganisms can be applied for enhanced oil recovery, as bacteria can plug the water-swept zones of a reservoir, thus altering the flow paths and improving sweep efficiency. However, complete understanding of the penetration...... behavior of bacteria is lacking, especially in chalk formations where characteristic pore throat sizes are comparable with the sizes of bacterial cells. In this study, two bacterial strains, Bacillus licheniformis 421 (spore-forming) and Pseudomonas putida K12 (non-spore forming) were used to investigate...... the penetration of bacteria into chalk and its effect on permeability reduction. The core plugs were produced from Stevns Klint outcrop with low permeability (2–4 mD) and with pore sizes comparable to bacterial sizes. Both types of bacteria were able to penetrate and to be transported through the cores to some...

  19. Gas Permeability Evolution Mechanism and Comprehensive Gas Drainage Technology for Thin Coal Seam Mining

    Directory of Open Access Journals (Sweden)

    Fangtian Wang

    2017-09-01

    Full Text Available A thin coal seam mined as a protective coal seam above a gas outburst coal seam plays a central role in decreasing the degree of stress placed on a protected seam, thus increasing gas permeability levels and desorption capacities to dramatically eliminate gas outburst risk for the protected seam. However, when multiple layers of coal seams are present, stress-relieved gas from adjacent coal seams can cause a gas explosion. Thus, the post-drainage of gas from fractured and de-stressed strata should be applied. Comprehensive studies of gas permeability evolution mechanisms and gas seepage rules of protected seams close to protective seams that occur during protective seam mining must be carried out. Based on the case of the LongWall (LW 23209 working face in the Hancheng coal mine, Shaanxi Province, this paper presents a seepage model developed through the FLAC3D software program (version 5.0, Itasca Consulting Group, Inc., Minneapolis, MI, USA from which gas flow characteristics can be reflected by changes in rock mass permeability. A method involving theoretical analysis and numerical simulation was used to analyze stress relief and gas permeability evolution mechanisms present during broken rock mass compaction in a goaf. This process occurs over a reasonable amount of extraction time and in appropriate locations for comprehensive gas extraction technologies. In using this comprehensive gas drainage technological tool, the safe and efficient co-extraction of thin coal seams and gas resources can be realized, thus creating a favorable environment for the safe mining of coal and gas outburst seams.

  20. Mechanical properties of high-strength concrete

    Science.gov (United States)

    Mokhtarzadeh, Alireza

    This report summarizes an experimental program conducted to investigate production techniques and mechanical properties of high strength concrete in general and to provide recommendations for using these concretes in manufacturing precast/prestressed bridge girders. Test variables included total amount and composition of cementitious material (portland cement, fly ash, and silica fume), type and brand of cement, type of silica fume (dry densified and slurry), type and brand of high-range water-reducing admixture, type of aggregate, aggregate gradation, maximum aggregate size, and curing. Tests were conducted to determine the effects of these variables on changes in compressive strength and modulus of elasticity over time, splitting tensile strength, modulus of rupture, creep, shrinkage, and absorption potential (as an indirect indicator of permeability). Also investigated were the effects of test parameters such as mold size, mold material, and end condition. Over 6,300 specimens were cast from approximately 140 mixes over a period of 3 years.

  1. Prediction of the permeability of neutral drugs inferred from their solvation properties

    KAUST Repository

    Milanetti, Edoardo

    2015-12-10

    Motivation: Determination of drug absorption is an important component of the drug discovery and development process in that it plays a key role in the decision to promote drug candidates to clinical trials. We have developed a method that, on the basis of an analysis of the dynamic distribution of water molecules around a compound obtained by molecular dynamics simulations, can compute a parameter-free value that correlates very well with the compound permeability measured using the human colon adenocarcinoma (Caco-2) cell line assay. Results: The method has been tested on twenty-three neutral drugs for which a consistent set of experimental data is available. We show here that our method reproduces the experimental data better than other existing tools. Furthermore it provides a detailed view of the relationship between the hydration and the permeability properties of molecules.

  2. In silico modeling on ADME properties of natural products: Classification models for blood-brain barrier permeability, its application to traditional Chinese medicine and in vitro experimental validation.

    Science.gov (United States)

    Zhang, Xiuqing; Liu, Ting; Fan, Xiaohui; Ai, Ni

    2017-08-01

    In silico modeling of blood-brain barrier (BBB) permeability plays an important role in early discovery of central nervous system (CNS) drugs due to its high-throughput and cost-effectiveness. Natural products (NP) have demonstrated considerable therapeutic efficacy against several CNS diseases. However, BBB permeation property of NP is scarcely evaluated both experimentally and computationally. It is well accepted that significant difference in chemical spaces exists between NP and synthetic drugs, which calls into doubt on suitability of available synthetic chemical based BBB permeability models for the evaluation of NP. Herein poor discriminative performance on BBB permeability of NP are first confirmed using internal constructed and previously published drug-derived computational models, which warrants the need for NP-oriented modeling. Then a quantitative structure-property relationship (QSPR) study on a NP dataset was carried out using four different machine learning methods including support vector machine, random forest, Naïve Bayes and probabilistic neural network with 67 selected features. The final consensus model was obtained with approximate 90% overall accuracy for the cross-validation study, which is further taken to predict passive BBB permeability of a large dataset consisting of over 10,000 compounds from traditional Chinese medicine (TCM). For 32 selected TCM molecules, their predicted BBB permeability were evaluated by in vitro parallel artificial membrane permeability assay and overall accuracy for in vitro experimental validation is around 81%. Interestingly, our in silico model successfully predicted different BBB permeation potentials of parent molecules and their known in vivo metabolites. Finally, we found that the lipophilicity, the number of hydrogen bonds and molecular polarity were important molecular determinants for BBB permeability of NP. Our results suggest that the consensus model proposed in current work is a reliable tool for

  3. Mechanics of layered anisotropic poroelastic media with applications to effective stress for fluid permeability

    Energy Technology Data Exchange (ETDEWEB)

    Berryman, J.G.

    2010-06-01

    The mechanics of vertically layered porous media has some similarities to and some differences from the more typical layered analysis for purely elastic media. Assuming welded solid contact at the solid-solid interfaces implies the usual continuity conditions, which are continuity of the vertical (layering direction) stress components and the horizontal strain components. These conditions are valid for both elastic and poroelastic media. Differences arise through the conditions for the pore pressure and the increment of fluid content in the context of fluid-saturated porous media. The two distinct conditions most often considered between any pair of contiguous layers are: (1) an undrained fluid condition at the interface, meaning that the increment of fluid content is zero (i.e., {delta}{zeta} = 0), or (2) fluid pressure continuity at the interface, implying that the change in fluid pressure is zero across the interface (i.e., {delta}p{sub f} = 0). Depending on the types of measurements being made on the system and the pertinent boundary conditions for these measurements, either (or neither) of these two conditions might be directly pertinent. But these conditions are sufficient nevertheless to be used as thought experiments to determine the expected values of all the poroelastic coefficients. For quasi-static mechanical changes over long time periods, we expect drained conditions to hold, so the pressure must then be continuous. For high frequency wave propagation, the pore-fluid typically acts as if it were undrained (or very nearly so), with vanishing of the fluid increment at the boundaries being appropriate. Poroelastic analysis of both these end-member cases is discussed, and the general equations for a variety of applications to heterogeneous porous media are developed. In particular, effective stress for the fluid permeability of such poroelastic systems is considered; fluid permeabilities characteristic of granular media or tubular pore shapes are treated

  4. Development of a New Apparatus for Investigating Acoustic Effects on Hydraulic Properties of Low-Permeability Geo-Materials

    Science.gov (United States)

    Nakajima, H.; Sawada, A.; Sugita, H.; Takeda, M.; Komai, T.; Zhang, M.

    2006-12-01

    Remediation of polluted soils and groundwater contaminated by heavy metals and non-aqueous phase liquids has been one of the challenging issues in the field of geo-environments. In-situ removal of the contaminants from low permeable soils, such as clay strata, is particularly difficult because of the low mobility, strong adsorption, and/or other various interactions within soils. Thus current remediation techniques, such as pump- and-treat method and even eletrokinetic method, generally suffer from low recovery rates and/or economically unacceptable long remediation periods. A perspective improvement in remediation technology is to couple the electrokinetic method with an application of acoustic waves. This so-called Electro-Acoustic Soil Decontamination (EASD) method has been proposed by Battelle Columbus Labs.(Muralidhara et al. 1990). Simultaneous application of an electric field and an acoustic field may produce a synergistic effect and result in further enhancement of water transport by electro-osmosis in principle, but there is still no fundamental data for the design of EASD method in practical applications. A number of investigations have shown that an application of acoustic waves can increase hydraulic conductivity and mobility of non-aqueous phase liquids in porous media. Most of the prior and ongoing researches in this area have been focused on increasing production from declining oil and gas reservoirs. During several field tests by the oil and gas industries, increases in oil production rates by 20% or more have been reported. However, underlying physical mechanisms for acoustically enhanced fluid transport are not adequately understood. In addition, majority of the past investigations has dealt with applications of large amplitude of acoustic waves to relatively permeable soils or fractured rocks, and there is little information if acoustic wave effectively enhances flow and contaminant transport for less permeable clayey soils. To evaluate the

  5. Change in mechanical properties of Antrim oil shale on retorting

    Energy Technology Data Exchange (ETDEWEB)

    Singh, S. P.; Hockings, W. A.; Kim, K.

    1979-01-01

    The decomposition of kerogen in oil shale and subsequent extraction of the decomposition products during the retorting process are known to alter the pore structure, resulting in changes in permeability, deformation and strength properties. Prediction of these changes is of fundamental importance in the design of in-situ retorting processes. This paper summarizes a comprehensive laboratory investigation on the changes in mechanical properties of Antrim oil shale on retorting at 500/sup 0/C. It was observed that kerogen plays an important role in the change of the properties on retorting. When subjected to heat, the degree of deformation, the extent of fracturing and the structural instability of the specimens appeared to be strongly dependent upon kerogen content. The values of elastic modulus, strength, and density decreased whereas maximum strain at failure increased on retorting. Significant increases in permeability and porosity also resulted from retorting. The most pronounced increase was observed in the permeability in the direction parallel to bedding which exceeded in some cases as much as 3 orders of magnitude. Microscopic observations of pore structures provided a qualitative support to data obtained in measurements of porosity and permeability.

  6. Influence of ionizing radiation and use of plasticizers on the mechanical properties and barrier properties of biodegradable films

    International Nuclear Information System (INIS)

    Ponce, Patricia; Parra, Duclerc F.; Carr, Laura G.; Sato, Juliana S.; Lugao, Ademar B.

    2005-01-01

    This work reports the influence of radiation and plasticizers on the barrier properties [water vapour permeability (WVP)] and mechanical properties (tensile strength and elongation) of edible films made of starch. These films were prepared with 4 g of starch/100 mL of water; 2-10 g polyethylene glycol (PEG)/100 g starch; and at natural pH. Tensile strength and percentage elongation were measured using a Mechanical Universal Testing Machine Instron 4400R and the water vapour permeability was determined according to ASTM E96-80 (ASTM, 1989). The mechanical properties of starch films are influenced by the plasticizer concentration. An increase in PEG content showed a considerable increase in elongation percentage and a decrease in the tensile strength of the films, also increase the permeability of the films in water. After irradiation, the barrier properties [water vapour permeability (WVP)] and mechanical properties (tensile strength and elongation) of the films were improved due to chemical reactions among polymer molecules. The films were irradiated at room temperature with gamma radiation. Irradiated starch cassava films with polyethylene glycol (PEG) as plasticizer have good flexibility and low water permeability, which indicate potential application as edible films (author)

  7. Mechanical properties of ordered alloys

    International Nuclear Information System (INIS)

    Kroupa, F.

    1977-06-01

    A survey is given of the metallophysical fundamentals of the mechanical properties of ordered two-phase alloys. Alloys of this type have a superlattice structure in a substitution mixed crystal. Ordering is achieved by slow cooling or by annealing below the critical temperature, during which ordering domains (antiphase domains) are formed. At a high degree of ordering, the dislocations are concentrated to form pairs, so-called super-dislocations. The mechanical properties may be selectively changed by varying different parameters (size of the ordering domains, degree of ordering, energy of the antiphase boundaries) by a special composition and heat treatment.(GSC) [de

  8. On the Mechanism(s of Membrane Permeability Transition in Liver Mitochondria of Lamprey, Lampetra fluviatilis L.: Insights from Cadmium

    Directory of Open Access Journals (Sweden)

    Elena A. Belyaeva

    2014-01-01

    Full Text Available Previously we have shown that opening of the mitochondrial permeability transition pore in its low conductance state is the case in hepatocytes of the Baltic lamprey (Lampetra fluviatilis L. during reversible metabolic depression taking place in the period of its prespawning migration when the exogenous feeding is switched off. The depression is observed in the last year of the lamprey life cycle and is conditioned by reversible mitochondrial dysfunction (mitochondrial uncoupling in winter and coupling in spring. To further elucidate the mechanism(s of induction of the mitochondrial permeability transition pore in the lamprey liver, we used Cd2+ and Ca2+ plus Pi as the pore inducers. We found that Ca2+ plus Pi induced the high-amplitude swelling of the isolated “winter” mitochondria both in isotonic sucrose and ammonium nitrate medium while both low and high Cd2+ did not produce the mitochondrial swelling in these media. Low Cd2+ enhanced the inhibition of basal respiration rate of the “winter” mitochondria energized by NAD-dependent substrates whereas the same concentrations of the heavy metal evoked its partial stimulation on FAD-dependent substrates. The above changes produced by Cd2+ or Ca2+ plus Pi in the “winter” mitochondria were only weakly (if so sensitive to cyclosporine A (a potent pharmacological desensitizer of the nonselective pore added alone and they were not sensitive to dithiothreitol (a dithiol reducing agent. Under monitoring of the transmembrane potential of the “spring” lamprey liver mitochondria, we revealed that Cd2+ produced its decrease on both types of the respiratory substrates used that was strongly hampered by cyclosporine A, and the membrane potential was partially restored by dithiothreitol. The effects of different membrane permeability modulators on the lamprey liver mitochondria function and the seasonal changes in their action are discussed.

  9. Mechanical Properties of Picea sitchensis

    DEFF Research Database (Denmark)

    Bräuner, Lise; Hoffmeyer, Preben; Poulsson, Lise

    2000-01-01

    the requirements at the same level as Danish grown Norway spruce. The study shows that Sitka spruce and Norway spruce of the same origin exhibit highly comparable mechanical properties. Key words: annual ring width, bending strength, characteristic strength, dry density, EN 338, INSTA 142, modulus of elasticity...

  10. Mechanical properties of organic nanofibers

    DEFF Research Database (Denmark)

    Kjelstrup-Hansen, Jakob; Hansen, Ole; Rubahn, H.R.

    2006-01-01

    Intrinsic elastic and inelastic mechanical Properties of individual, self-assembled, quasi-single-crystalline para-hexaphenylene nanofibers supported on substrates with different hydrophobicities are investigated as well as the interplay between the fibers and the underlying substrates. We find...

  11. 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 degreases 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.

  12. HIV-1 Tat reduces nephrin in human podocytes: a potential mechanism for enhanced glomerular permeability in HIV-associated nephropathy.

    Science.gov (United States)

    Doublier, Sophie; Zennaro, Cristina; Spatola, Tiziana; Lupia, Enrico; Bottelli, Antonella; Deregibus, Maria Chiara; Carraro, Michele; Conaldi, Pier Giulio; Camussi, Giovanni

    2007-02-19

    To determine whether HIV-1 Tat may directly alter glomerular permeability in HIV-associated nephropathy (HIVAN). Heavy proteinuria is a hallmark of HIVAN. The slit diaphragm is the ultimate glomerular filtration barrier critical for maintaining the efficiency of the ultrafiltration unit of the kidney. In this study, we evaluated the direct effect of Tat protein on the permeability of isolated glomeruli and on the expression of nephrin, the main slit diaphragm component, by human cultured podocytes. Permeability was studied by measuring the permeability to albumin in isolated rat glomeruli. We also evaluated the expression of nephrin in human cultured podocytes by using immunofluorescence and Western blot. We found that Tat increased albumin permeability in isolated glomeruli, and rapidly induced the redistribution and loss of nephrin in cultured podocytes. Pretreatment of glomeruli and podocytes with blocking antibodies showed that Tat reduced nephrin expression by engaging vascular endothelial growth factor receptors types 2 and 3 and the integrin alphavbeta3. Pre-incubation of podocytes with two platelet-activating factor (PAF) receptor antagonists prevented the loss and redistribution of nephrin induced by Tat, suggesting that PAF is an intracellular mediator of Tat action. Tat induced a rapid PAF synthesis by podocytes. When podocytes transfected to overexpress PAF-acetylhydrolase, the main catabolic enzyme of PAF, were stimulated with Tat, the redistribution and loss of nephrin was abrogated. The present results define a mechanism by which Tat may reduce nephrin expression in podocytes, thus increasing glomerular permeability. This provides new insights in the understanding of HIVAN pathogenesis.

  13. Mechanical properties of irradiated materials

    International Nuclear Information System (INIS)

    Robertson, I.M.; Robach, J.; Wirth, B.

    2001-01-01

    The effect of irradiation on the mechanical properties of metals is considered with particular attention being paid to the development of defect-free channels following uniaxial tensile loading. The in situ transmission electron microscope deformation technique is coupled with dislocation dynamic computer simulations to reveal the fundamental processes governing the elimination of defects by glissile dislocations. The observations of preliminary experiments are reported.(author)

  14. An investigation of the moisture sorption and permeability properties of mill-fabricated oriented strandboard

    Science.gov (United States)

    Timusk, Paul Christopher

    This thesis brings the disciplines of Building Science and Wood Science together in the study of the moisture-related properties of oriented strand board (OSB). Using controlled mill-manufactured panels specifically made for this project, this research reveals how the sorption and permeance properties of OSB are affected by several variables including production parameters and physical panel properties, moisture-history, and relative humidity exposure. Since OSB varies in composition through its thickness, this study isolated and tested various core and surface components. Permeability and sorption properties of individual OSB layers, intact panel sections, and panel sections that had undergone cyclic wetting and drying or relative humidity cycling prior to testing, were evaluated. After laboratory testing and analysis, a set of OSB permeance and sorption values were entered into the material database of a finite-element hygrothermal computer modeling program. Relying on this data, a series of hygrothermal wall simulations were carried out using standard wall sections exposed to various climate conditions found throughout North America. These simulations revealed that the results vary widely depending upon the permeance and sorption values used. Thus the common practice of characterizing a range of OSB products with various moisture histories by using a single permeance or sorption value may not be wise.

  15. Prediction of Geomechanical Properties from Thermal Conductivity of Low-Permeable Reservoirs

    Science.gov (United States)

    Chekhonin, Evgeny; Popov, Evgeny; Popov, Yury; Spasennykh, Mikhail; Ovcharenko, Yury; Zhukov, Vladislav; Martemyanov, Andrey

    2016-04-01

    A key to assessing a sedimentary basin's hydrocarbon prospect is correct reconstruction of thermal and structural evolution. It is impossible without adequate theory and reliable input data including among other factors thermal and geomechanical rock properties. Both these factors are also important in geothermal reservoirs evaluation and carbon sequestration problem. Geomechanical parameters are usually estimated from sonic logging and rare laboratory measurements, but sometimes it is not possible technically (low quality of the acoustic signal, inappropriate borehole and mud conditions, low core quality). No wonder that there are attempts to correlate the thermal and geomechanical properties of rock, but no one before did it with large amount of high quality thermal conductivity data. Coupling results of sonic logging and non-destructive non-contact thermal core logging opens wide perspectives for studying a relationship between the thermal and geomechanical properties. More than 150 m of full size cores have been measured at core storage with optical scanning technique. Along with results of sonic logging performed with Sonic Scanner in different wells drilled in low permeable formations in West Siberia (Russia) it provided us with unique data set. It was established a strong correlation between components of thermal conductivity (measured perpendicular and parallel to bedding) and compressional and shear acoustic velocities in Bazhen formation. As a result, prediction of geomechanical properties via thermal conductivity data becomes possible, corresponding results was demonstrated. The work was supported by the Russian Ministry of Education and Science, project No. RFMEFI58114X0008.

  16. Mechanical properties of carbon nanotubes

    Science.gov (United States)

    Salvetat, J.-P.; Bonard, J.-M.; Thomson, N. H.; Kulik, A. J.; Forró, L.; Benoit, W.; Zuppiroli, L.

    A variety of outstanding experimental results on the elucidation of the elastic properties of carbon nanotubes are fast appearing. These are based mainly on the techniques of high-resolution transmission electron microscopy (HRTEM) and atomic force microscopy (AFM) to determine the Young's moduli of single-wall nanotube bundles and multi-walled nanotubes, prepared by a number of methods. These results are confirming the theoretical predictions that carbon nanotubes have high strength plus extraordinary flexibility and resilience. As well as summarising the most notable achievements of theory and experiment in the last few years, this paper explains the properties of nanotubes in the wider context of materials science and highlights the contribution of our research group in this rapidly expanding field. A deeper understanding of the relationship between the structural order of the nanotubes and their mechanical properties will be necessary for the development of carbon-nanotube-based composites. Our research to date illustrates a qualitative relationship between the Young's modulus of a nanotube and the amount of disorder in the atomic structure of the walls. Other exciting results indicate that composites will benefit from the exceptional mechanical properties of carbon nanotubes, but that the major outstanding problem of load transfer efficiency must be overcome before suitable engineering materials can be produced.

  17. Mechanical properties of fracture zones

    International Nuclear Information System (INIS)

    Leijon, B.

    1993-05-01

    Available data on mechanical characteristics of fracture zones are compiled and discussed. The aim is to improve the basis for adequate representation of fracture zones in geomechanical models. The sources of data researched are primarily borehole investigations and case studies in rock engineering, involving observations of fracture zones subjected to artificial load change. Boreholes only yield local information about the components of fracture zones, i.e. intact rock, fractures and various low-strength materials. Difficulties are therefore encountered in evaluating morphological and mechanical properties of fracture zones from borehole data. Although often thought of as macroscopically planar features, available field data consistently show that fracture zones are characterized by geometrical irregularities such as thickness variations, surface undulation and jogs. These irregularities prevail on all scales. As a result, fracture zones are on all scales characterized by large, in-plane variation of strength- and deformational properties. This has important mechanical consequences in terms of non-uniform stress transfer and complex mechanisms of shear deformation. Field evidence for these findings, in particular results from the underground research laboratory in Canada and from studies of induced fault slip in deep mines, is summarized and discussed. 79 refs

  18. Superconducting state mechanisms and properties

    CERN Document Server

    Kresin, Vladimir Z; Wolf, Stuart A

    2014-01-01

    'Superconducting State' provides a very detailed theoretical treatment of the key mechanisms of superconductivity, including the current state of the art (phonons, magnons, and plasmons). A very complete description is given of the electron-phonon mechanism responsible for superconductivity in the majority of superconducting systems, and the history of its development, as well as a detailed description of the key experimental techniques used to study the superconducting state and determine the mechanisms. In addition, there are chapters describing the discovery and properties of the key superconducting compounds that are of the most interest for science, and applications including a special chapter on the cuprate superconductors. It provides detailed treatments of some very novel aspects of superconductivity, including multiple bands (gaps), the "pseudogap" state, novel isotope effects beyond BCS, and induced superconductivity.

  19. Hydro-mechanical coupling and permeability of an unsaturated swelling clay under hydrous and thermal stress: sorption curve and water permeability

    International Nuclear Information System (INIS)

    Olchitzky, E.

    2002-02-01

    The use of swelling clay for engineered safety barriers of radioactive waste disposal require the understanding of its thermal-hydro-mechanical behaviour. This work concerns particularly the characterization and the modelling of the behaviour of one of these clays: the FoCa7 clay. The characteristics of the studied material are: the sorption (desorption) curve and the water permeability. For each of them, new experiments have allowed to acquire data in fields still few explored: in temperature (between 20 and 80 C) for the sorption curve and in the unsaturated field for the water permeability. The analysis of these results and of bibliographic data has allowed in one hand to estimate the importance of the hysteresis phenomenon and the temperature influence on the sorption curve and in another hand, to establish the requirement to introduce in the modelling of the sorption curve, a plastic parameter due to the irreversible deformations occurring during the compaction. Moreover, the tests carried out for data acquirement have been used too to give validation elements to the non linear behaviour laws proposed by O. Coussy and P. Dangla for the non saturated porous media. The particularity of these laws is to suppose the existence of an effective constraint in the non saturated field, this shows the importance of the validation elements presented here. (O.M.)

  20. Classification of cassava starch films by physicochemical properties and water vapor permeability quantification by FTIR and PLS.

    Science.gov (United States)

    Henrique, C M; Teófilo, R F; Sabino, L; Ferreira, M M C; Cereda, M P

    2007-05-01

    Cassava starches are widely used in the production of biodegradable films, but their resistance to humidity migration is very low. In this work, commercial cassava starch films were studied and classified according to their physicochemical properties. A nondestructive method for water vapor permeability determination, which combines with infrared spectroscopy and multivariate calibration, is also presented. The following commercial cassava starches were studied: pregelatinized (amidomax 3550), carboxymethylated starch (CMA) of low and high viscosities, and esterified starches. To make the films, 2 different starch concentrations were evaluated, consisting of water suspensions with 3% and 5% starch. The filmogenic solutions were dried and characterized for their thickness, grammage, water vapor permeability, water activity, tensile strength (deformation force), water solubility, and puncture strength (deformation). The minimum thicknesses were 0.5 to 0.6 mm in pregelatinized starch films. The results were treated by means of the following chemometric methods: principal component analysis (PCA) and partial least squares (PLS) regression. PCA analysis on the physicochemical properties of the films showed that the differences in concentration of the dried material (3% and 5% starch) and also in the type of starch modification were mainly related to the following properties: permeability, solubility, and thickness. IR spectra collected in the region of 4000 to 600 cm(-1) were used to build a PLS model with good predictive power for water vapor permeability determination, with mean relative errors of 10.0% for cross-validation and 7.8% for the prediction set.

  1. Mechanical properties of irradiated beryllium

    International Nuclear Information System (INIS)

    Beeston, J.M.; Longhurst, G.R.; Wallace, R.S.

    1992-01-01

    Beryllium is planned for use as a neutron multiplier in the tritium breeding blanket of the International Thermonuclear Experimental Reactor (ITER). After fabricating samples of beryllium at densities varying from 80 to 100% of the theoretical density, we conducted a series of experiments to measure the effect of neutron irradiation on mechanical properties, especially strength and ductility. Samples were irradiated in the Advanced Test Reactor (ATR) to a neutron fluence of 2.6 x 10 25 n/m 2 (E > MeV) at an irradiation temperature of 75deg C. These samples were subsequently compression-tested at room temperature, and the results were compared with similar tests on unirradiated specimens. We found that the irradiation increased the strength by approximately four times and reduced the ductility to approximately one fourth. Failure was generally ductile, but the 80% dense irradiated samples failed in brittle fracture with significant generation of fine particles and release of small quantities of tritium. (orig.)

  2. Mechanical properties of irradiated beryllium

    Science.gov (United States)

    Beeston, J. M.; Longhurst, G. R.; Wallace, R. S.; Abeln, S. P.

    1992-10-01

    Beryllium is planned for use as a neutron multiplier in the tritium breeding blanket of the International Thermonuclear Experimental Reactor (ITER). After fabricating samples of beryllium at densities varying from 80 to 100% of the theoretical density, we conducted a series of experiments to measure the effect of neutron irradiation on mechanical properties, especially strength and ductility. Samples were irradiated in the Advanced Test Reactor (ATR) to a neutron fluence of 2.6 × 10 25 n/m 2 ( E > 1 MeV) at an irradiation temperature of 75°C. These samples were subsequently compression-tested at room temperature, and the results were compared with similar tests on unirradiated specimens. We found that the irradiation increased the strength by approximately four times and reduced the ductility to approximately one fourth. Failure was generally ductile, but the 80% dense irradiated samples failed in brittle fracture with significant generation of fine particles and release of small quantities of tritium.

  3. Mechanical properties of Stripa granite

    International Nuclear Information System (INIS)

    Stephansson, O.; Swan, G.; Leijon, B.

    1978-01-01

    For the determination of the mechanical properties of Stripa Granite samples were taken from the boreholes in the vicinity of the test site. The granite type taken from these different sources is of variable character. For the purpose of numerical calculations performed in projects related to the waste storage research program the following parameters have been determined: Young's modulus, Poisson's ratio, compressive fracture stress and expansion coefficient as a function of temperature 20< T<200C; Young's modulus and compressive fracture stress as a function of confining pressure; Brazilian tensile fracture stress; residual shear stress as a function of normal stress; anisotropy ratio for Young's modulus and compressive fracture stress; dilatational wave velocity and deduced dynamic Young's modulus. A brief description of the test methods and the results for each test are presented

  4. Montmorillonite polyaniline nanocomposites: Preparation, characterization and investigation of mechanical properties

    International Nuclear Information System (INIS)

    Soundararajah, Q.Y.; Karunaratne, B.S.B.; Rajapakse, R.M.G.

    2009-01-01

    The interest in clay polymer nanocomposites (CPN) materials, initially developed by researchers at Toyota, has grown dramatically over the last decade. They have attracted great interest, both in industry and in academia, because they often exhibit remarkable improvement in materials' properties when compared with virgin polymer or conventional micro- and macro-composites. These improvements can include high moduli, increased strength and heat resistance, decreased gas permeability and flammability, optical transparency and increased biodegradability of biodegradable polymers. Such enhancement in the properties of nanocomposites occurs mostly due to their unique phase morphology and improved interfacial properties. Because of these enhanced properties they find applications in the fields of electronics, automobile industry, packaging, and construction. This study aims at investigating the mechanical property enhancement of polyaniline (PANI) intercalated with montmorillonite (MMT) clay. The MMT-PANI nanocomposites displayed improved mechanical properties compared to the neat polymer or clay. The enhancement was achieved at low clay content probably due to its exfoliated structure. The increased interfacial areas and improved bond characteristics may attribute to the mechanical property enhancement

  5. Mechanical properties of irradiated beryllium

    Energy Technology Data Exchange (ETDEWEB)

    Beeston, J.M.; Longhurst, G.R.; Wallace, R.S. (EG and G Idaho, Inc., Idaho Falls, ID (United States). Idaho National Engineering Lab.); Abeln, S.P. (EG and G Rocky Flats, Inc., Golden, CO (United States))

    1992-10-01

    Beryllium is planned for use as a neutron multiplier in the tritium breeding blanket of the International Thermonuclear Experimental Reactor (ITER). After fabricating samples of beryllium at densities varying from 80 to 100% of the theoretical density, we conducted a series of experiments to measure the effect of neutron irradiation on mechanical properties, especially strength and ductility. Samples were irradiated in the Advanced Test Reactor (ATR) to a neutron fluence of 2.6 x 10[sup 25] n/m[sup 2] (E > MeV) at an irradiation temperature of 75deg C. These samples were subsequently compression-tested at room temperature, and the results were compared with similar tests on unirradiated specimens. We found that the irradiation increased the strength by approximately four times and reduced the ductility to approximately one fourth. Failure was generally ductile, but the 80% dense irradiated samples failed in brittle fracture with significant generation of fine particles and release of small quantities of tritium. (orig.).

  6. Microwave absorbing property and complex permittivity and permeability of graphene–CdS nanocomposite

    International Nuclear Information System (INIS)

    Zhang, Dong-Dong; Zhao, Dong-Lin; Zhang, Ji-Ming; Bai, Li-Zhong

    2014-01-01

    Graphical abstract: Graphene–CdS (G–CdS) nanocomposite with a good structural interface and enhanced microwave absorption has been successfully and directly synthesized from graphene oxide via a facile hydrothermal approach. The permittivity of G–CdS nanocomposite presents triple dielectric relaxations by constructing a good structural G–CdS interface. The triple dielectric relaxations are critical to improve the microwave absorption of the G–CdS nanocomposite. Highlights: • Graphene–CdS (G–CdS) nanocomposite was directly synthesized from graphene oxide. • The G–CdS nanocomposite exhibits enhanced microwave absorption. • The permittivity of G–CdS nanocomposite presents triple dielectric relaxations. -- Abstract: The graphene–CdS (G–CdS) nanocomposite with enhanced microwave absorption was directly synthesized from graphene oxide (GO) via a facile hydrothermal approach, during which the formation of CdS nanoparticles and the reduction of GO occured simultaneously. The morphology, structure, microwave absorbing property, complex permittivity and permeability of G–CdS nanocomposite were systematically investigated by transmission electron microscope, X-ray diffraction and the coaxial line method. The complex permittivity of G–CdS nanocomposite presents triple dielectric relaxations with constructing a good structural graphene–CdS interface. The triple dielectric relaxations were critical to improve the microwave absorption of G–CdS nanocomposite. The G–CdS nanocomposite achieved a reflection loss below –10 dB in the frequency range of 5.2–18 GHz when adjusting the thicknesses from 2 to 5 mm, which was mainly ascribed to the proper electromagnetic matching of the CdS nanoparticles and graphene sheets, and the triple dielectric relaxations. The G–CdS nanocomposite is promising as a lightweight and wide-frequency microwave absorber

  7. Internal hydrological mechanism of permeable pavement and interaction with subsurface water

    Science.gov (United States)

    Many communities are implementing green infrastructure stormwater control measures (SCMs) in urban environments across the U.S. to mimic pre-urban, natural hydrology more closely. Permeable pavement is one SCM infrastructure that has been commonly selected for both new and retro...

  8. Martensite and bainite in steels: transformation mechanism and mechanical properties

    International Nuclear Information System (INIS)

    Bhadeshia, H.K.D.H.

    1997-01-01

    Many essential properties of iron alloys depend on what actually happens when one allotropic form gives way to another, i.e. on the mechanism of phase change. The dependence of the mechanical properties on the atomic mechanism by which bainite and martensite grow is the focus of this paper. The discussion is illustrated in the context of some common engineering design parameters, and with a brief example of the inverse problem in which the mechanism may be a function of the mechanical properties. (orig.)

  9. Selected mechanical properties of modified beech wood

    Directory of Open Access Journals (Sweden)

    Jiří Holan

    2008-01-01

    Full Text Available This thesis deals with an examination of mechanical properties of ammonia treated beach wood with a trademark Lignamon. For determination mechanical properties were used procedures especially based on ČSN. From the results is noticeable increased density of wood by 22% in comparison with untreated beach wood, which makes considerable increase of the most mechanical wood properties. Considering failure strength was raised by 32% and modulus of elasticity was raised at average about 46%.

  10. The casting and mechanism of formation of semi-permeable polymer membranes in a microgravity environment

    Science.gov (United States)

    Vera, I.

    The National Electric Company of Venezuela, C.A.D.A.F.E., is sponsoring the development of this experiment which represents Venezuela's first scientific experiment in space. The apparatus for the automatic casting of polymer thin films will be contained in NASA's payload No. G-559 of the Get Away Special program for a future orbital space flight in the U.S. Space Shuttle. Semi-permeable polymer membranes have important applications in a variety of fields, such as medecine, energy, and pharmaceuticals, and in general fluid separation processes such as reverse osmosis, ultra-filtration, and electro-dialysis. The casting of semi-permeable membranes in space will help to identify the roles of convection in determining the strucutre of these membranes.

  11. An alpha-adrenergic receptor mechanism controlling potassium permeability in the rat lacrimal gland acinar cell

    International Nuclear Information System (INIS)

    Parod, R.J.; Putney, J.W. Jr.

    1978-01-01

    Rat lacrimal gland slices, incubated in a balanced, buffered salt solution, were found to be physiologically stable for up to 2 hr with respect to 0 2 consumption, extracellular space, and water and ion content. The release of 86 Rb serves as a good substitute for 42 K in monitoring the movement of K through the cell membrane. Adrenaline appears to increase membrane permeability to K as evidenced by an increase in the rate of 86 Rb efflux. This response to adrenaline was blocked by phentolamine but not by propranolol and was mimicked by phenylephrine but not by isoprenaline. The magnitude of the 86 Rb release indicates that it is being released, at least in part, from the lacrimal gland acinar cell. It is concluded that the lacrimal gland acinar cell has an α-adrenergic receptor, activation of which leads to an increase in membrane permeability to K. (author)

  12. Skin mechanical properties and modeling: A review.

    Science.gov (United States)

    Joodaki, Hamed; Panzer, Matthew B

    2018-04-01

    The mechanical properties of the skin are important for various applications. Numerous tests have been conducted to characterize the mechanical behavior of this tissue, and this article presents a review on different experimental methods used. A discussion on the general mechanical behavior of the skin, including nonlinearity, viscoelasticity, anisotropy, loading history dependency, failure properties, and aging effects, is presented. Finally, commonly used constitutive models for simulating the mechanical response of skin are discussed in the context of representing the empirically observed behavior.

  13. The Permeability Enhancing Mechanism of DMSO in Ceramide Bilayers Simulated by Molecular Dynamics

    Science.gov (United States)

    Notman, Rebecca; den Otter, Wouter K.; Noro, Massimo G.; Briels, W. J.; Anwar, Jamshed

    2007-01-01

    The lipids of the topmost layer of the skin, the stratum corneum, represent the primary barrier to molecules penetrating the skin. One approach to overcoming this barrier for the purpose of delivery of active molecules into or via the skin is to employ chemical permeability enhancers, such as dimethylsulfoxide (DMSO). How these molecules exert their effect at the molecular level is not understood. We have investigated the interaction of DMSO with gel-phase bilayers of ceramide 2, the predominant lipid in the stratum corneum, by means of molecular dynamics simulations. The simulations satisfactorily reproduce the phase behavior and the known structural parameters of ceramide 2 bilayers in water. The effect of DMSO on the gel-phase bilayers was investigated at various concentrations over the range 0.0−0.6 mol fraction DMSO. The DMSO molecules accumulate in the headgroup region and weaken the lateral forces between the ceramides. At high concentrations of DMSO (≥0.4 mol fraction), the ceramide bilayers undergo a phase transition from the gel phase to the liquid crystalline phase. The liquid-crystalline phase of ceramides is expected to be markedly more permeable to solutes than the gel phase. The results are consistent with the experimental evidence that high concentrations of DMSO fluidize the stratum corneum lipids and enhance permeability. PMID:17513383

  14. PHYSICAL AND CHEMICAL PROPERTIES IN RELATION WITH SOIL PERMEABILITY IN THE AREA OF VELIKA GORICA WELL FIELD

    Directory of Open Access Journals (Sweden)

    Zoran Kovač

    2018-01-01

    Full Text Available Hydraulic parameters affects behaviour of various ions in soils. The goal of this paper was to get better understanding of relationship between physical and chemical properties and soil permeability at the location of case study profile Velika Gorica, based on the physical and chemical data. Soil profile is situated in the Eutric Cambisol of the Zagreb aquifer, Croatia. Zagreb aquifer represents the only source of potable water for inhabitants of the City of Zagreb and Zagreb County. Based on the data obtained from particle size analysis, soil hydraulic parameters and measured water content, unsaturated hydraulic conductivity values were calculated for the estimation of soil profile permeability. Soil water retention curves and unsaturated hydraulic conductivities are very similar for all depths because soil content does not change significantly through the depth. Determination of anions and cations on soil samples was performed using the method of ion chromatography. Results showed decrease of ions concentrations after 0.6 m depth. SAR distribution in the soil profile shows that SAR values are not significantly changing at the soil profile. The highest CEC and EC values are determined in horizon Bw developed in 0.6 m depth which is consistent with highest SAR value and ions concentrations. All results suggest that physical and chemical properties of investigated profile are in relationship with soil permeability.

  15. The novel oral imatinib microemulsions: physical properties, cytotoxicity activities and improved Caco-2 cell permeability.

    Science.gov (United States)

    Gundogdu, Evren; Karasulu, Hatice Yesim; Koksal, Cinel; Karasulu, Ercüment

    2013-01-01

    The objective of this study was to formulate imatinib (IM) loaded to water-in-oil (w/o) microemulsions as an alternative formulation for cancer therapy and to evaluate the cytotoxic effect of microemulsions Caco-2 and MCF-7. Moreover, permeability studies were also performed with Caco-2 cells. W/o microemulsion systems were developed by using pseudo-ternary phase diagram. According to cytotoxicity studies, all formulations did not exert a cytotoxic effect on Caco-2 cells. Furthermore, all formulations had a significant cytotoxic effect on MCF-7 cells and the cytotoxic effect of M3IM was significantly more than that of other microemulsions and IM solution (p < 0.05). The permeability studies of IM across Caco-2 cells showed that permeability value from apical to basolateral was higher than permeability value of other formulations. In conclusion, the microemulsion formulations as a drug carrier, especially M3IM formulation, may be used as an effective alternative breast cancer therapy for oral delivery of IM.

  16. Enhancement of mechanical properties of 123 superconductors

    Science.gov (United States)

    Balachandran, U.

    1995-04-25

    A composition and method are disclosed of preparing YBa{sub 2}Cu{sub 3}O{sub 7{minus}x} superconductor. Addition of tin oxide containing compounds to YBCO superconductors results in substantial improvement of fracture toughness and other mechanical properties without affect on T{sub c}. About 5-20% additions give rise to substantially improved mechanical properties.

  17. Enhancement of mechanical properties of 123 superconductors

    Science.gov (United States)

    Balachandran, Uthamalingam

    1995-01-01

    A composition and method of preparing YBa.sub.2 Cu.sub.3 O.sub.7-x superconductor. Addition of tin oxide containing compounds to YBCO superconductors results in substantial improvement of fracture toughness and other mechanical properties without affect on T.sub.c. About 5-20% additions give rise to substantially improved mechanical properties.

  18. Mechanical properties of rock at high temperatures

    International Nuclear Information System (INIS)

    Kinoshita, Naoto; Abe, Tohru; Wakabayashi, Naruki; Ishida, Tsuyoshi.

    1997-01-01

    The laboratory tests have been performed in order to investigate the effects of temperature up to 300degC and pressure up to 30 MPa on the mechanical properties of three types of rocks, Inada granite, Sanjoume andesite and Oya tuff. The experimental results indicated that the significant differences in temperature dependence of mechanical properties exist between the three rocks, because of the difference of the factors which determine the mechanical properties of the rocks. The effect of temperature on the mechanical properties for the rocks is lower than that of pressure and water content. Temperature dependence of the mechanical properties is reduced by increase in pressure in the range of pressure and temperature investigated in this paper. (author)

  19. Mechanical properties of chemically modified portuguese pinewood

    OpenAIRE

    Lopes, Duarte B; Mai, Carsten; Militz, Holger

    2014-01-01

    To turn wood into a construction material with enhanced properties, many methods of chemical modification have been developed in the last few decades. In this work, mechanical properties of pine wood were chemically modified, compared and evaluated. Maritime pine wood (Pinus pinaster) was modified with four chemical processes: 1,3-dimethylol-4,5- dihydroxyethyleneurea, N-methylol melamine formaldehyde, tetra-alkoxysilane and wax. The following mechanical properties were assessed experiment...

  20. Evolution of mechanical characteristics and permeability of clayey materials under the influence of thermal loadings

    International Nuclear Information System (INIS)

    Boucly-Norotte, V.

    1991-01-01

    This research thesis reports the study of the effects on a long term of temperature variations on the volume and texture of clayey soils, notably with respect to their initial petro-physical and petro-graphical characteristics, and to their consolidation state. From an experimental point of view, this research is based on the monitoring of the volume strain and of the permeability of samples placed in an oedometric cell and submitted to thermal loadings within the 20 C - 110 C range. A thorough texture investigation (mercury-based porosimetry, observation by scanning electronic microscopy, and so on) before and after testing allows the evolution of material texture to be assessed [fr

  1. Energy transfer properties and mechanisms

    International Nuclear Information System (INIS)

    1991-01-01

    This report discusses the energy transfer mechanisms in azulene, benzene, toluene, and isotopomers. Also discussed is the coupled energy reservoirs model, quantum effects in energy transfer, NO 2 energy transfer, densities of states, the reactant states model, and O 3 excited electronic states

  2. Nanocompósitos de PEAD/PEBDL: avaliação da esfoliação da argila organofílica pela aplicação do modelo de Nielsen e das propriedades mecânicas, ópticas e permeabilidade PEAD/PEBDL composites: evaluation of the exfoliation of organophilic clay using the Nielsen model and of the mechanical, optical and permeability properties

    Directory of Open Access Journals (Sweden)

    Ana R. Morales

    2010-01-01

    Full Text Available Uma blenda de polietileno de alta densidade e polietileno de baixa densidade (PEAD/PEBDL comumente utilizada em filmes de embalagem foi modificada com argila montmorilonita organofílica comercial para obter nanocompósitos com melhores propriedades de barreira. Amostras com 5 e 7,5% de argila (em massa foram estudadas em diferentes condições de processamento. Filmes produzidos com os nanocompósitos foram avaliados quanto à dispersão da argila por difração de raio X e Microscopia Eletrônica de Transmissão. As propriedades de barreira dos filmes foram determinadas pelas medições de permeabilidade ao oxigênio e ao vapor d'água. As propriedades mecânicas e ópticas também foram determinadas. Observou-se uma estrutura com a argila parcialmente esfoliada e intercalada. A permeabilidade ao oxigênio diminuiu significativamente enquanto a permeabilidade à água foi pouco influenciada. As propriedades mecânicas e a transparência dos filmes foram pouco alteradas. O modelo de Nielsen foi aplicado para os dados de permeabilidade relativa e demonstrou ser um ótimo recurso para a avaliação do grau de esfoliação da argila para as diferentes amostras, que foram confirmadas pelas análises realizadas em microscopia eletrônica de transmissão.A typical high density polyethylene and linear low density polyethylene (HDPE/LLDPE blend used in flexible packaging was modified with commercial organophylic montmorilonite clay to obtain nanocomposites with superior barrier properties. Samples with 5 and 7.5% of clay were prepared under different processing conditions. Films produced from the nanocomposites were evaluated in terms of oxygen and water vapor permeation and also by X-ray diffraction and Transmission Electron Microscopy. Tensile and optical properties were also evaluated. The clay showed to be intercalated and partially exfoliated. The oxygen permeation was mainly reduced and the vapor permeation was weakly modified. The mechanical

  3. Energy transfer properties and mechanisms

    International Nuclear Information System (INIS)

    Barker, J.R.

    1993-01-01

    Since no single experimental technique is the best method for energy transfer experiments, we have used both time-dependent infrared fluorescence (IRF) and time-dependent thermal lensing (TDTL) to study energy transfer in various systems. We are investigating pump-probe techniques employing resonance enhanced multiphoton ionization (REMPI). IRF was used to study benzene, azulene, and toluene. TDTL was used to study CS 2 and SO 2 (data not given for latter). Large molecule energy transfer mechanisms are discussed. 10 figs

  4. Stress state evaluation in low carbon and TRIP steels by magnetic permeability

    International Nuclear Information System (INIS)

    Kouli, M.-E.; Giannakis, M

    2016-01-01

    Magnetic permeability is an indicative factor for the steel health monitoring. The measurements of magnetic permeability lead to the evaluation of the stress state of any ferromagnetic steel. The magnetic permeability measurements were conducted on low carbon and TRIP steel samples, which were subjected to both tensile and compressive stresses. The results indicated a direct correlation of the magnetic permeability with the mechanical properties, the stress state and the microstructural features of the examined samples. (paper)

  5. A technique to investigate the mechanism of uniform corrosion in the presence of a semi-permeable membrane

    International Nuclear Information System (INIS)

    King, F.

    1987-01-01

    A technique to investigate the mechanism of uniform corrosion in the presence of a semi-permeable membrane is described. For both the anodic and cathodic half-reactions three possible rate-determining steps are considered: transport of species through the bulk solution diffusion layer, transport of species through the membrane and the electrochemical reaction itself. The technique is based on the measurement of the corrosion potential, E CORR , of a rotating disc electrode under steady-state conditions. The variation of E CORR with the oxidant concentration, the thickness of the diffusion layer and the membrane thickness is used to identify the rate-determining step for each half-reaction. This technique should be of use in the study of the corrosion behaviour of candidate materials for nuclear waste disposal containers. An understanding of the mechanism of uniform corrosion will enable confident predictions to be made concerning the long-term behaviour of such containers

  6. Synthesis, microstructure and mechanical properties of ceria ...

    Indian Academy of Sciences (India)

    Unknown

    ceria stabilized zirconia powders with improved mechanical properties. Ce–ZrO2 with 20 wt% ... structural ceramic materials (Garvie et al 1975; Evans and. Cannon 1986) ... thermal expansion matching with that of iron alloys. (Tsukuma and ...

  7. AAnti-leakage mechanism and effect of sodium aescinate on the permeability of blood-brain barrier

    Directory of Open Access Journals (Sweden)

    Ping GUO

    2012-02-01

    Full Text Available Objective  To study the anti-leakage mechanism and protective effect of sodium aescinate on the blood-brain barrier of rats acutely exposed to hypoxia. Methods  Seventy-five healthy SD rats were randomly divided into 3 groups (25 each: normoxic control (NC, simple hypoxic (SH and drug treated (DT group. Acute hypoxia brain edema rat model was established by a simulation of acute high-altitude hypoxia for 5 days. The cerebral water content was determined by dry-wet method. The permeability of the blood-brain barrier (BBB was evaluated by Evans blue (EB method. The pathological change of the brain was detected by HE staining. The state of BBB tight junction (TJ and ultrastructures of the brain tissues were observed by lanthanum nitrate tracer method under transmission electron microscope (TEM. Protein and mRNA expression of Occludin, Zo-1 and Claudin-5 were investigated by immunohistochemistry, Western-blotting and real-time PCR respectively. Results  After exposure to acute hypoxia for 5 days, compared with NC group, the water content of brain in SH group increased obviously (PPPPPConclusion  Acute hypoxia exposure may lead to a remarkable decline of the expressions of rat's brain Occludin protein and the Occludin, Zo-1 and Claudin-5 mRNA, and an obvious increase of BBB permeability. Sodium aescinate can up-regulate the expression level of these molecules and decrease BBB permeability, thus playing a profitable role of anti-leakage and BBB protection.

  8. Microstructures and mechanical properties of aging materials

    International Nuclear Information System (INIS)

    Liaw, P.K.; Viswanathan, R.; Murty, K.L.; Simonen, E.P.; Frear, D.

    1993-01-01

    This book contains a collection of papers presented at the symposium on ''Microstructures and Mechanical Properties of Aging Materials,'' that was held in Chicago, IL. November 2-5, 1992 in conjunction with the Fall Meeting of The Minerals, Metals and Materials Society (TMS). The subjects of interest in the symposium included: (1) mechanisms of microstructural degradation, (2) effects of microstructural degradation on mechanical behavior, (3) development of life prediction methodology for in-service structural and electronic components, (4) experimental techniques to monitor degradation of microstructures and mechanical properties, and (5) effects of environment on microstructural degradation and mechanical properties. Individual papers have been processed separately for inclusion in the appropriate data bases

  9. Delayed astrocytic contact with cerebral blood vessels in FGF-2 deficient mice does not compromise permeability properties at the developing blood-brain barrier.

    Science.gov (United States)

    Saunders, Norman R; Dziegielewska, Katarzyna M; Unsicker, Klaus; Ek, C Joakim

    2016-11-01

    The brain functions within a specialized environment tightly controlled by brain barrier mechanisms. Understanding the regulation of barrier formation is important for understanding brain development and may also lead to finding new ways to deliver pharmacotherapies to the brain; access of many potentially promising drugs is severely hindered by these barrier mechanisms. The cellular composition of the neurovascular unit of the blood-brain barrier proper and their effects on regulation of its function are beginning to be understood. One hallmark of the neurovascular unit in the adult is the astroglial foot processes that tightly surround cerebral blood vessels. However their role in barrier formation is still unclear. In this study we examined barrier function in newborn, juvenile and adult mice lacking fibroblast growth factor-2 (FGF-2), which has been shown to result in altered astroglial differentiation during development. We show that during development of FGF-2 deficient mice the astroglial contacts with cerebral blood vessels are delayed compared with wild-type animals. However, this delay did not result in changes to the permeability properties of the blood brain barrier as assessed by exclusion of either small or larger sized molecules at this interface. In addition cerebral vessels were positive for tight-junction proteins and we observed no difference in the ultrastructure of the tight-junctions. The results indicate that the direct contact of astroglia processes to cerebral blood vessels is not necessary for either the formation of the tight-junctions or for basic permeability properties and function of the blood-brain barrier. © 2016 Wiley Periodicals, Inc. Develop Neurobiol 76: 1201-1212, 2016. © 2016 Wiley Periodicals, Inc.

  10. Assessment of mechanical properties of isolated bovine intervertebral discs from multi-parametric magnetic resonance imaging.

    Science.gov (United States)

    Recuerda, Maximilien; Périé, Delphine; Gilbert, Guillaume; Beaudoin, Gilles

    2012-10-12

    The treatment planning of spine pathologies requires information on the rigidity and permeability of the intervertebral discs (IVDs). Magnetic resonance imaging (MRI) offers great potential as a sensitive and non-invasive technique for describing the mechanical properties of IVDs. However, the literature reported small correlation coefficients between mechanical properties and MRI parameters. Our hypothesis is that the compressive modulus and the permeability of the IVD can be predicted by a linear combination of MRI parameters. Sixty IVDs were harvested from bovine tails, and randomly separated in four groups (in-situ, digested-6h, digested-18h, digested-24h). Multi-parametric MRI acquisitions were used to quantify the relaxation times T1 and T2, the magnetization transfer ratio MTR, the apparent diffusion coefficient ADC and the fractional anisotropy FA. Unconfined compression, confined compression and direct permeability measurements were performed to quantify the compressive moduli and the hydraulic permeabilities. Differences between groups were evaluated from a one way ANOVA. Multi linear regressions were performed between dependent mechanical properties and independent MRI parameters to verify our hypothesis. A principal component analysis was used to convert the set of possibly correlated variables into a set of linearly uncorrelated variables. Agglomerative Hierarchical Clustering was performed on the 3 principal components. Multilinear regressions showed that 45 to 80% of the Young's modulus E, the aggregate modulus in absence of deformation HA0, the radial permeability kr and the axial permeability in absence of deformation k0 can be explained by the MRI parameters within both the nucleus pulposus and the annulus pulposus. The principal component analysis reduced our variables to two principal components with a cumulative variability of 52-65%, which increased to 70-82% when considering the third principal component. The dendograms showed a natural

  11. Influence of Storage on Briquettes Mechanical Properties

    Directory of Open Access Journals (Sweden)

    Brožek M.

    2014-09-01

    Full Text Available The effects of the storage place, placing manner, and storage time on mechanical properties of briquettes made from birch chips were laboratorily tested. A unique methodology developed by the present author enabling a relatively easy assessment of mechanical properties of the briquettes is described. The briquettes properties were evaluated by their density and rupture force determination. From the test results it follows that if the briquettes are stored in a well closed plastic bag, neither the place nor the storage time influence significantly their life time. When stored in a net plastic bag, the briquettes get seriously damaged, namely depending on their storage place and storage time.

  12. Alyssum homolocarpum seed gum-polyvinyl alcohol biodegradable composite film: Physicochemical, mechanical, thermal and barrier properties.

    Science.gov (United States)

    Monjazeb Marvdashti, Leila; Koocheki, Arash; Yavarmanesh, Masoud

    2017-01-02

    Films made from Alyssum homolocarpum seeds gum (AHSG) have poor mechanical and barrier (to oxygen) properties. In the present study poly vinyl alcohol (PVA) was used to improve the physicochemical properties of AHSG films. Results indicated that the addition of PVA significantly increased the moisture content, solubility, elongation at break (EB) and transparency while it decreased the density, oxygen permeability, chroma, water contact angle and Young modulus of AHSG based films. Films with higher AHSG to PVA ratios had lower water vapor permeability (WVP). The light barrier measurements presented low values of transparency at 600nm for PVA/AHSG films, indicating that films were very transparent while they had excellent barrier properties against UV light. Results for FTIR, DSC and SEM showed a clear interaction between PVA and AHSG, forming a new material. These results indicated that PVA/AHSG blend films had good compatibility. Copyright © 2016 Elsevier Ltd. All rights reserved.

  13. Barrier, mechanical and optical properties of whey protein concentrate films

    Directory of Open Access Journals (Sweden)

    Viviane Machado Azevedo

    2014-08-01

    Full Text Available Whey is recognized as a valuable source of high quality protein and, when processed as protein concentrate, may be used in the production of biodegradable films. The objective of the study was to develop films of whey protein concentrate 80% (WPC at concentrations of 6, 8, 10 and 12% and evaluate the influence of this factor in the barrier, mechanical and optical properties of the films. Treatments showed moisture content with a mean value of 22.10% ± 0.76and high solubility values between 56.67 to 62.42%. Thus, there is little or no influence of varying the concentration of WPC in these properties and high hydrophilicity of the films. With increasing concentration of WPC, increases the water vapor permeability of the films (7.42 x 10-13 to 3.49 x 10-12 g.m-1.s-1.Pa-1. The treatment at the concentration of 6% of WPC showed a higher modulus of elasticity (287.90 ± 41.79 MPa. Thegreater rigidity in films with higher concentrations is possibly due to the greater number of bonds between molecules of the polymeric matrix. The films have the same puncture resistance. The increased concentration of WPC promotes resistance to the action of a localized force. In general, films of whey protein concentrate in the tested concentrations exhibited slightly yellowish color and transparency, and can be used in food packaging that requiring intermediate permeability to water vapor, to keep moisture and texture desired.

  14. Investigation of Stabilised Batu Pahat Soft Soil Pertaining on its CBR and Permeability Properties for Road Construction

    Science.gov (United States)

    Mohd Idrus, M. M.; Singh, J. S. M.; Musbah, A. L. A.; Wijeyesekera, D. C.

    2016-07-01

    Soil stabilization by adding materials such as cement, lime and bitumen is one of the effective methods for improving the geotechnical properties of soils [11] Nano-particle is one of the newest additives and many studies about using nano-particle in soil improvement has been done but it was given less attention when soft clay soils stabilization is concerned. To evaluate the strength characteristics of stabilized Batu Pahat soft clay, laboratory investigation on early strength gained by the stabilized soil must be conducted to formulate a suitable and economical mix design [10]. To achieve such purpose, the study examined the effect of NanoClay on the California Bearing Ratio and the Permeability of soft clay. The results gained shows that the Nano-Clay is able to increase the strength of the soft clay [9]. The California Bearing Ratio of the soil is increase significantly where the results for the highest percentage of admixture is 14.4% while the permeability of the soil decreases significantly with increasing Nano-Clay whereby the results of the highest percentage of admixture is 2.0187x10-11 m/s. After doing this research, it is proven that Nano-clay can contribute towards better soil stabilization and enhance the quality of soil as subgrade and foundation at large.

  15. Ultra high pressure liquid chromatography. Column permeability and changes of the eluent properties.

    Science.gov (United States)

    Gritti, Fabrice; Guiochon, Georges

    2008-04-11

    The behavior of four similar liquid chromatography columns (2.1mm i.d. x 30, 50, 100, and 150 mm, all packed with fine particles, average d(p) approximately 1.7 microm, of bridged ethylsiloxane/silica hybrid-C(18), named BEH-C(18)) was studied in wide ranges of temperature and pressure. The pressure and the temperature dependencies of the viscosity and the density of the eluent (pure acetonitrile) along the columns were also derived, using the column permeabilities and applying the Kozeny-Carman and the heat balance equations. The heat lost through the external surface area of the chromatographic column was directly derived from the wall temperature of the stainless steel tube measured with a precision of +/-0.2 degrees C in still air and +/-0.1 degrees C in the oven compartment. The variations of the density and viscosity of pure acetonitrile as a function of the temperature and pressure was derived from empirical correlations based on precise experimental data acquired between 298 and 373 K and at pressures up to 1.5 kbar. The measurements were made with the Acquity UPLC chromatograph that can deliver a maximum flow rate of 2 mL/min and apply a maximum column inlet pressure of 1038 bar. The average Kozeny-Carman permeability constant of the columns was 144+/-3.5%. The temperature hence the viscosity and the density profiles of the eluent along the column deviate significantly from linear behavior under high-pressure gradients. For a 1000 bar pressure drop, we measured DeltaT=25-30 K, (Deltaeta/eta) approximately 100%, and (Deltarho/rho) approximately 10%. These results show that the radial temperature profiles are never fully developed within 1% for any of the columns, even under still-air conditions. This represents a practical advantage regarding the apparent column efficiency at high flow rates, since the impact of the differential analyte velocity between the column center and the column wall is not maximum. The interpretation of the peak profiles recorded in

  16. SWCNT Composites, Interfacial Strength and Mechanical Properties

    DEFF Research Database (Denmark)

    Ma, Jing; Larsen, Mikael

    2013-01-01

    Abstract: Single-Walled Carbon Nanotubes (SWCNT) have despite the superior mechanical properties not fully lived up to the promise as reinforcement in SWCNT composites. The strain transfer from matrix to carbon nanotubes (CNT) is poorly understood and is caused by both fewer localized strong...... is applied to the composite materials. The effect of polymer matrix, modification and concentration of the CNTs are discussed. The strain transfer i.e. 2D band shift under tension is compared to the mechanical properties of the SWCNT composite material....

  17. Mechanical properties of human atherosclerotic intima tissue.

    Science.gov (United States)

    Akyildiz, Ali C; Speelman, Lambert; Gijsen, Frank J H

    2014-03-03

    Progression and rupture of atherosclerotic plaques in coronary and carotid arteries are the key processes underlying myocardial infarctions and strokes. Biomechanical stress analyses to compute mechanical stresses in a plaque can potentially be used to assess plaque vulnerability. The stress analyses strongly rely on accurate representation of the mechanical properties of the plaque components. In this review, the composition of intima tissue and how this changes during plaque development is discussed from a mechanical perspective. The plaque classification scheme of the American Heart Association is reviewed and plaques originating from different vascular territories are compared. Thereafter, an overview of the experimental studies on tensile and compressive plaque intima properties are presented and the results are linked to the pathology of atherosclerotic plaques. This overview revealed a considerable variation within studies, and an enormous dispersion between studies. Finally, the implications of the dispersion in experimental data on the clinical applications of biomechanical plaque modeling are presented. Suggestions are made on mechanical testing protocol for plaque tissue and on using a standardized plaque classification scheme. This review identifies the current status of knowledge on plaque mechanical properties and the future steps required for a better understanding of the plaque type specific material properties. With this understanding, biomechanical plaque modeling may eventually provide essential support for clinical plaque risk stratification. Copyright © 2014 Elsevier Ltd. All rights reserved.

  18. Casein films: effects of formulation, environmental conditions, and addition of citric pectin on the structure and mechanical properties

    Science.gov (United States)

    Thin casein films for food packaging applications reportedly possess good strength and low oxygen permeability, but low water-resistance and elasticity. Modifying and customizing the mechanical properties of the films to target specific behaviors depending on environmental conditions would enable a...

  19. Microfluidic Foaming: A Powerful Tool for Tailoring the Morphological and Permeability Properties of Sponge-like Biopolymeric Scaffolds.

    Science.gov (United States)

    Costantini, Marco; Colosi, Cristina; Jaroszewicz, Jakub; Tosato, Alessia; Święszkowski, Wojciech; Dentini, Mariella; Garstecki, Piotr; Barbetta, Andrea

    2015-10-28

    Ordered porous polymeric materials can be engineered to present highly ordered pore arrays and uniform and tunable pore size. These features prompted a number of applications in tissue engineering, generation of meta materials, and separation and purification of biomolecules and cells. Designing new and efficient vistas for the generation of ordered porous materials is an active area of research. Here we investigate the potential of microfluidic foaming within a flow-focusing (FF) geometry in producing 3D regular sponge-like polymeric matrices with tailored morphological and permeability properties. The challenge in using microfluidic systems for the generation of polymeric foams is in the high viscosity of the continuous phase. We demonstrate that as the viscosity of the aqueous solution increases, the accessible range of foam bubble fraction (Φb) and bubble diameter (Db) inside the microfluidic chip tend to narrow progressively. This effect limits the accessible range of geometric properties of the resulting materials. We further show that this problem can be rationally tackled by appropriate choice of the concentration of the polymer. We demonstrate that via such optimization, the microfluidic assisted synthesis of porous materials becomes a facile and versatile tool for generation of porous materials with a wide range of pore size and pore volume. Moreover, we demonstrate that the size of interconnects among pores-for a given value of the gas fraction-can be tailored through the variation of surfactant concentration. This, in turn, affects the permeability of the materials, a factor of key importance in flow-through applications and in tissue engineering.

  20. Hydrogen permeability through metals

    International Nuclear Information System (INIS)

    Pisarev, A.A.; Tsvetkov, I.V.; Marenkov, E.D.; Yarko, S.S.

    2011-01-01

    The mechanisms of hydrogen permeability through one-layer and multi-layer membranes are considered. The effect of surface roughness, crystal defects, cracks and pores is described. Mathematical description of the processes is given [ru

  1. Mechanical properties of additively manufactured octagonal honeycombs

    Energy Technology Data Exchange (ETDEWEB)

    Hedayati, R., E-mail: rezahedayati@gmail.com [Department of Mechanical Engineering, Amirkabir University of Technology (Tehran Polytechnic), Hafez Ave, Tehran (Iran, Islamic Republic of); Department of Biomechanical Engineering, Faculty of Mechanical, Maritime, and Materials Engineering, Delft University of Technology (TU Delft), Mekelweg 2, 2628 CD Delft (Netherlands); Sadighi, M.; Mohammadi-Aghdam, M. [Department of Mechanical Engineering, Amirkabir University of Technology (Tehran Polytechnic), Hafez Ave, Tehran (Iran, Islamic Republic of); Zadpoor, A.A. [Department of Biomechanical Engineering, Faculty of Mechanical, Maritime, and Materials Engineering, Delft University of Technology (TU Delft), Mekelweg 2, 2628 CD Delft (Netherlands)

    2016-12-01

    Honeycomb structures have found numerous applications as structural and biomedical materials due to their favourable properties such as low weight, high stiffness, and porosity. Application of additive manufacturing and 3D printing techniques allows for manufacturing of honeycombs with arbitrary shape and wall thickness, opening the way for optimizing the mechanical and physical properties for specific applications. In this study, the mechanical properties of honeycomb structures with a new geometry, called octagonal honeycomb, were investigated using analytical, numerical, and experimental approaches. An additive manufacturing technique, namely fused deposition modelling, was used to fabricate the honeycomb from polylactic acid (PLA). The honeycombs structures were then mechanically tested under compression and the mechanical properties of the structures were determined. In addition, the Euler-Bernoulli and Timoshenko beam theories were used for deriving analytical relationships for elastic modulus, yield stress, Poisson's ratio, and buckling stress of this new design of honeycomb structures. Finite element models were also created to analyse the mechanical behaviour of the honeycombs computationally. The analytical solutions obtained using Timoshenko beam theory were close to computational results in terms of elastic modulus, Poisson's ratio and yield stress, especially for relative densities smaller than 25%. The analytical solutions based on the Timoshenko analytical solution and the computational results were in good agreement with experimental observations. Finally, the elastic properties of the proposed honeycomb structure were compared to those of other honeycomb structures such as square, triangular, hexagonal, mixed, diamond, and Kagome. The octagonal honeycomb showed yield stress and elastic modulus values very close to those of regular hexagonal honeycombs and lower than the other considered honeycombs. - Highlights: • The octagonal

  2. Probing cell mechanical properties with microfluidic devices

    Science.gov (United States)

    Rowat, Amy

    2012-02-01

    Exploiting flow on the micron-scale is emerging as a method to probe cell mechanical properties with 10-1000x advances in throughput over existing technologies. The mechanical properties of cells and the cell nucleus are implicated in a wide range of biological contexts: for example, the ability of white blood cells to deform is central to immune response; and malignant cells show decreased stiffness compared to benign cells. We recently developed a microfluidic device to probe cell and nucleus mechanical properties: cells are forced to deform through a narrow constrictions in response to an applied pressure; flowing cells through a series of constrictions enables us to probe the ability of hundreds of cells to deform and relax during flow. By tuning the constriction width so it is narrower than the width of the cell nucleus, we can specifically probe the effects of nuclear physical properties on whole cell deformability. We show that the nucleus is the rate-limiting step in cell passage: inducing a change in its shape to a multilobed structure results in cells that transit more quickly; increased levels of lamin A, a nuclear protein that is key for nuclear shape and mechanical stability, impairs the passage of cells through constrictions. We are currently developing a new class of microfluidic devices to simultaneously probe the deformability of hundreds of cell samples in parallel. Using the same soft lithography techniques, membranes are fabricated to have well-defined pore distribution, width, length, and tortuosity. We design the membranes to interface with a multiwell plate, enabling simultaneous measurement of hundreds of different samples. Given the wide spectrum of diseases where altered cell and nucleus mechanical properties are implicated, such a platform has great potential, for example, to screen cells based on their mechanical phenotype against a library of drugs.

  3. AN EXPERIMENTAL STUDY ON STRENGTH AND PERMEABILITY PROPERTIES OF HIGH STRENGTH CONCRETE

    OpenAIRE

    Yedla Venkatesh * & G. Kalyan

    2017-01-01

    Concrete is the most important engineering material and the addition of some other materials may change the properties of concrete. Mineral additions which are also known as mineral admixtures have been used with cements for many years. There are two types of materials crystalline and non crystalline. High performance concrete (HPC) exceeds the properties and constructability of normal concrete. Micro silica or silica fume is very fine non crystalline material. Silica fume is produced in elec...

  4. Soil mechanical properties of MBT waste from Luxembourg, Germany and Thailand

    Directory of Open Access Journals (Sweden)

    Pattaraporn Pimolthai

    2014-12-01

    Full Text Available Mechanical and biological treatments (MBT of waste have become well known in Europe and Asia. The maximum particle size of waste is reduced by the removal of larger plastic materials from municipal solid waste during mechanical processing. The mechanical properties of the MBT waste are significantly changed by this process. An effective treatment system can lead to a better quality of output materials which do not cause environmental problems. This paper shows the comparative mechanical properties of MBT wastes from Luxembourg, Germany and Thailand. This research focused on the smaller 10 mm-fraction of MBT samples, in order to describe and evaluate the potential application of the small size material as a cover liner in landfill sites. Therefore the smaller 10 mm-fraction of MBT samples were tested for geotechnical properties. The small size waste particles were analysed in laboratory tests in order to determine their particle size, particle shape, compaction, permeability, shear strength, porosity and water absorption capacity, including comparison with the properties of soil material. The results showed that reduced particles were likely to act as a compact, low permeable material with a high potential for water absorption. The amount of remaining fibre and foil components in the materials cause different mechanical and hydraulic behaviours in the samples. The leachate of MBT samples showed very low concentrations of chemical oxygen demand, ammonium, and heavy metals, compared to the landfill leachate of untreated waste.

  5. Pit slope manual chapter 3. Mechanical properties

    Energy Technology Data Exchange (ETDEWEB)

    Gyenge, M.; Herget, G.

    1977-01-01

    Guidance is given on the procedures required to obtain adequate knowledge of the mechanical properties of the soils and rocks which constitute the walls of the pit. The reason why certain data is necessary is explained and the tests required to obtain these data are described.

  6. Mechanical properties of flexible knitted composites

    NARCIS (Netherlands)

    Haan, de J.; Peijs, A.A.J.M.

    1996-01-01

    This study investigates the influence of the matrix material and the degree of prestretch of a knitted fibre structure on the mechanical properties of knitted composites with low fibre volume fractions. By embedding a flexible textile structure in an elastomeric matrix, composite materials are

  7. Mechanical properties of bioactive glass putty formulations

    NARCIS (Netherlands)

    van Gestel, N.A.P.; Geurts, J.A.P.; Hulsen, D.J.W.; Hofmann, S.; Ito, K.; van Rietbergen, B.; Arts, J.J.C.

    2016-01-01

    Introduction: Bioactive glass (BAG) has been studied widely and seems to be a very promising biomaterial in regeneration of large bone defects and osteomyelitis treatment, because of its bone bonding and antibacterial properties[1]-[5]. Its high stiffness could potentially also enable mechanical

  8. Material, compressional and mechanical properties of Borassus ...

    African Journals Online (AJOL)

    The compressional and mechanical properties of tablet formulations incorporating native and modified Borassus aethiopum starches as binder were evaluated. The native Borassus aethiopum starch (BAS) was modified to yield fully gelatinised starch (FGBAS) and microcrystalline starch (MBAS). The compressional ...

  9. Investigations on the microstructure and mechanical properties

    Indian Academy of Sciences (India)

    This paper addresses the weldability, microstructure and mechanical properties of the multi-pass welding of super-duplex stainless steel (SDSS). Pulsed current gas tungsten arc welding (PCGTAW) was carried out employing ER2553 and ERNiCrMo-4 fillers. Microstructure examination showed the presence of austenite in ...

  10. Mechanical properties of ion-implanted alumina

    International Nuclear Information System (INIS)

    Pope, S.G.

    1988-01-01

    Monolithic oxide ceramics are being proposed as structural materials in continuously more-demanding applications. The demands being placed on these materials have caused concern pertaining to the continued growth of oxide structural ceramics due to limited toughness. The realization that ceramic strength and toughness can be affected by surface conditions has led to many surface-modification techniques, all striving to improve the mechanical properties of ceramics. Along these lines, the effects of ion implantation as a surface modification technique for improvement of the mechanical properties of alumina were studied. Initially, sapphire samples were implanted with elemental ion species that would produce oxide precipitates within the sapphire surface when annealed in an oxygen-containing atmosphere. Optimum conditions as determined from implantation into sapphire were then used to modify a polycrystalline alumina. Specific modifications in microhardness, indentation fracture toughness and flexure strength are reported for the parameters studied. Microstructure and phase relationships related to modified surfaces properties are also reported

  11. Nanostructured thin films and coatings mechanical properties

    CERN Document Server

    2010-01-01

    The first volume in "The Handbook of Nanostructured Thin Films and Coatings" set, this book concentrates on the mechanical properties, such as hardness, toughness, and adhesion, of thin films and coatings. It discusses processing, properties, and performance and provides a detailed analysis of theories and size effects. The book presents the fundamentals of hard and superhard nanocomposites and heterostructures, assesses fracture toughness and interfacial adhesion strength of thin films and hard nanocomposite coatings, and covers the processing and mechanical properties of hybrid sol-gel-derived nanocomposite coatings. It also uses nanomechanics to optimize coatings for cutting tools and explores various other coatings, such as diamond, metal-containing amorphous carbon nanostructured, and transition metal nitride-based nanolayered multilayer coatings.

  12. Food mechanical properties and dietary ecology.

    Science.gov (United States)

    Berthaume, Michael A

    2016-01-01

    Interdisciplinary research has benefitted the fields of anthropology and engineering for decades: a classic example being the application of material science to the field of feeding biomechanics. However, after decades of research, discordances have developed in how mechanical properties are defined, measured, calculated, and used due to disharmonies between and within fields. This is highlighted by "toughness," or energy release rate, the comparison of incomparable tests (i.e., the scissors and wedge tests), and the comparison of incomparable metrics (i.e., the stress and displacement-limited indices). Furthermore, while material scientists report on a myriad of mechanical properties, it is common for feeding biomechanics studies to report on just one (energy release rate) or two (energy release rate and Young's modulus), which may or may not be the most appropriate for understanding feeding mechanics. Here, I review portions of materials science important to feeding biomechanists, discussing some of the basic assumptions, tests, and measurements. Next, I provide an overview of what is mechanically important during feeding, and discuss the application of mechanical property tests to feeding biomechanics. I also explain how 1) toughness measures gathered with the scissors, wedge, razor, and/or punch and die tests on non-linearly elastic brittle materials are not mechanical properties, 2) scissors and wedge tests are not comparable and 3) the stress and displacement-limited indices are not comparable. Finally, I discuss what data gathered thus far can be best used for, and discuss the future of the field, urging researchers to challenge underlying assumptions in currently used methods to gain a better understanding between primate masticatory morphology and diet. © 2016 Wiley Periodicals, Inc.

  13. Microstructure and Mechanical Properties of Porous Mullite

    Science.gov (United States)

    Hsiung, Chwan-Hai Harold

    Mullite (3 Al2O3 : 2 SiO2) is a technologically important ceramic due to its thermal stability, corrosion resistance, and mechanical robustness. One variant, porous acicular mullite (ACM), has a unique needle-like microstructure and is the material platform for The Dow Chemical Company's diesel particulate filter AERIFY(TM). The investigation described herein focuses on the microstructure-mechanical property relationships in acicular mullites as well as those with traditional porous microstructures with the goal of illuminating the critical factors in determining their modulus, strength, and toughness. Mullites with traditional pore morphologies were made to serve as references via slipcasting of a kaolinite-alumina-starch slurry. The starch was burned out to leave behind a pore network, and the calcined body was then reaction-sintered at 1600C to form mullite. The samples had porosities of approximately 60%. Pore size and shape were altered by using different starch templates, and pore size was found to influence the stiffness and toughness. The ACM microstructure was varied along three parameters: total porosity, pore size, and needle size. Total porosity was found to dominate the mechanical behavior of ACM, while increases in needle and pore size increased the toughness at lower porosities. ACM was found to have much improved (˜130%) mechanical properties relative to its non-acicular counterpart at the same porosity. A second set of investigations studied the role of the intergranular glassy phase which wets the needle intersections of ACM. Removal of the glassy phase via an HF etch reduced the mechanical properties by ˜30%, highlighting the intergranular phase's importance to the enhanced mechanical properties of ACM. The composition of the glassy phase was altered by doping the ACM precursor with magnesium and neodymium. Magnesium doping resulted in ACM with greatly reduced fracture strength and toughness. Studies showed that the mechanical properties of the

  14. The effect of chain length and lipid phase transitions on the selective permeability properties of liposomes

    NARCIS (Netherlands)

    Blok, M.C.; Neut-Kok, E.C.M. van der; Deenen, L.L.M. van; Gier, J. de

    1975-01-01

    This paper describes experiments showing the importance of the fatty acid chain length on the barrier properties of liposomal bilayers, prepared from saturated lecithins, under conditions of lateral phase separation. 1. 1.|Above the gel to liquid crystalline phase transition temperature,

  15. Mechanical Properties of Stable Glasses Using Nanoindentation

    Science.gov (United States)

    Wolf, Sarah; Liu, Tianyi; Jiang, Yijie; Ablajan, Keyume; Zhang, Yue; Walsh, Patrick; Turner, Kevin; Fakhraai, Zahra

    Glasses with enhanced stability over ordinary, liquid quenched glasses have been formed via the process of Physical Vapor Deposition (PVD) by using a sufficiently slow deposition rate and a substrate temperature slightly below the glass transition temperature. These stable glasses have been shown to exhibit higher density, lower enthalpy, and better kinetic stability over ordinary glass, and are typically optically birefringent, due to packing and orientational anisotropy. Given these exceptional properties, it is of interest to further investigate how the properties of stable glasses compare to those of ordinary glass. In particular, the mechanical properties of stable glasses remain relatively under-investigated. While the speed of sound and elastic moduli have been shown to increase with increased stability, little is known about their hardness and fracture toughness compared to ordinary glasses. In this study, glasses of 9-(3,5-di(naphthalen-1-yl)phenyl)anthracene were deposited at varying temperatures relative to their glass transition temperature, and their mechanical properties measured by nanoindentation. Hardness and elastic modulus of the glasses were compared across substrate temperatures. After indentation, the topography of these films were studied using Atomic Force Microscopy (AFM) in order to further compare the relationship between thermodynamic and kinetic stability and mechanical failure. Z.F. and P.W. acknowledge funding from NSF(DMREF-1628407).

  16. PVA/Polysaccharides Blended Films: Mechanical Properties

    Directory of Open Access Journals (Sweden)

    Fábio E. F. Silva

    2013-01-01

    Full Text Available Blends of polyvinyl alcohol (PVA and angico gum (AG and/or cashew gum (CG were used to produce films by casting method. Morphological and mechanical properties of these films were studied and compared to the properties of a commercial collagen membrane of bovine origin (MBO. The films presented thickness varying from 70 to 140 μm (PVA/AG and 140 to 200 μm (PVA/CG. Macroscopic analysis showed that a PVA/CG film was very similar to MBO regarding the color and transparency. The higher values of tensile strength (TS and elastic modulus (EM were observed in the film. On the other hand, PVA/CG and PVA/CG-AG presented the highest value of percentage of elongation (E%. Pearson’s Correlation Analysis revealed a positive correlation between TS and EM and a negative correlation between E% and EM. The PVA/CG film presented mechanical properties very similar to MBO, with the advantage of a higher E% (11.96 than MBO (2.94. The properties of the PVA blended films depended on the polysaccharide added in the blend, as well as the acid used as a catalyst. However, all produced films presented interesting mechanical characteristics which enables several biotechnological applications.

  17. Mechanical properties of nuclear waste glasses

    International Nuclear Information System (INIS)

    Connelly, A.J.; Hand, R.J.; Bingham, P.A.; Hyatt, N.C.

    2011-01-01

    The mechanical properties of nuclear waste glasses are important as they will determine the degree of cracking that may occur either on cooling or following a handling accident. Recent interest in the vitrification of intermediate level radioactive waste (ILW) as well as high level radioactive waste (HLW) has led to the development of new waste glass compositions that have not previously been characterised. Therefore the mechanical properties, including Young's modulus, Poisson's ratio, hardness, indentation fracture toughness and brittleness of a series of glasses designed to safely incorporate wet ILW have been investigated. The results are presented and compared with the equivalent properties of an inactive simulant of the current UK HLW glass and other nuclear waste glasses from the literature. The higher density glasses tend to have slightly lower hardness and indentation fracture toughness values and slightly higher brittleness values, however, it is shown that the variations in mechanical properties between these different glasses are limited, are well within the range of published values for nuclear waste glasses, and that the surveyed data for all radioactive waste glasses fall within relatively narrow range.

  18. Mechanical properties of cork under contact stresses

    International Nuclear Information System (INIS)

    Parralejo, A. D.; Guiberteau, F.; Fortes, M. A.; Rosa, M. E.

    2001-01-01

    In this work our interest is focussed on the mechanical behaviour of natural cork under contact stresses. Many of the applications of this curious material are related with its mechanical response under such a stress field, however this topic has not been still sufficiently considered in the scientific literature. For this purpose, we proposed the use of Hertzian indentation tests. By using this mythology we have investigated the cork structure influence on the corresponding mechanical properties. Our results reveal a clear mechanical anisotropy effect. Moreover, the elastic modulus corresponding to specific directions have been estimated. Several are the main advantages of this specific test mythology versus traditional uniaxial compression tests, specially simplicity and local character. (Author) 9 refs

  19. PVA/Polysaccharides Blended Films: Mechanical Properties

    OpenAIRE

    Silva, Fábio E. F.; Di-Medeiros, Maria Carolina B.; Batista, Karla A.; Fernandes, Kátia F.

    2013-01-01

    Blends of polyvinyl alcohol (PVA) and angico gum (AG) and/or cashew gum (CG) were used to produce films by casting method. Morphological and mechanical properties of these films were studied and compared to the properties of a commercial collagen membrane of bovine origin (MBO). The films presented thickness varying from 70 to 140 μm (PVA/AG) and 140 to 200 μm (PVA/CG). Macroscopic analysis showed that a PVA/CG film was very similar to MBO regarding the color and transparency. The higher valu...

  20. Notional Permeability

    NARCIS (Netherlands)

    Kik, R.; Van den Bos, J.P.; Maertens, J.; Verhagen, H.J.; Van der Meer, J.W.

    2012-01-01

    Different layer design of a rock slope and under layers has a large effect on the strengths on the rock slope itself. In the stability formula developed of VAN DER MEER [1988] this effect is represented by the term Notional Permeability with symbol P. A more open, or permeable, structure underneath

  1. Microstructure mechanical properties relationship in bainitic structures

    International Nuclear Information System (INIS)

    Altuna, M. A.; Gutierrez, I.

    2005-01-01

    In the present work, the microstructures and their mechanical properties have been studies in different bainitic structures. therefore, different bainitic morphologies have been produced by isothermal treatments carried out at different temperatures. For these steels, 400-450 degree centigree is the optimum range of temperatures in order to obtain bainitic structures. If the Temperature is higher, perlite is also formed and if it is lower, martensite is obtained during quenching. SEM and EBSD/OIM techniques were applied in order to study the microstructure. Tensile tests were carried out for mechanical characterization. (Author) 20 refs

  2. Investigation of Mechanical Properties and Interfacial Mechanics of Crystalline Nanomaterials

    Science.gov (United States)

    Qin, Qingquan

    Nanowires (NWs) and nanotubes (NTs) are critical building blocks of nanotechnologies. The operation and reliability of these nanomaterials based devices depend on their mechanical properties of the nanomaterials, which is therefore important to accurately measure the mechanical properties. Besides, the NW--substrate interfaces also play a critical role in both mechanical reliability and electrical performance of these nanodevices, especially when the size of the NW is small. In this thesis, we focus on the mechanical properties and interface mechanics of three important one dimensional (1D) nanomaterials: ZnO NWs, Ag NWs and Si NWs. For the size effect study, this thesis presents a systematic experimental investigation on the elastic and failure properties of ZnO NWs under different loading modes: tension and buckling. Both tensile modulus (from tension) and bending modulus (from buckling) were found to increase as the NW diameter decreased from 80 to 20 nm. The elastic modulus also shows loading mode dependent; the bending modulus increases more rapidly than the tensile modulus. The tension experiments showed that fracture strain and strength of ZnO NWs increase as the NW diameter decrease. A resonance testing setup was developed to measure elastic modulus of ZnO NWs to confirm the loading mode dependent effect. A systematic study was conducted on the effect of clamping on resonance frequency and thus measured Young's modulus of NWs via a combined experiment and simulation approach. A simple scaling law was provided as guidelines for future designs to accurate measure elastic modulus of a cantilevered NW using the resonance method. This thesis reports the first quantitative measurement of a full spectrum of mechanical properties of five-fold twinned Ag NWs including Young's modulus, yield strength and ultimate tensile strength. In situ tensile testing of Ag NWs with diameters between 34 and 130 nm was carried out inside a SEM. Young's modulus, yield strength and

  3. Fuel cladding mechanical properties for transient analysis

    International Nuclear Information System (INIS)

    Johnson, G.D.; Hunter, C.W.; Hanson, J.E.

    1976-01-01

    Out-of-pile simulated transient tests have been conducted on irradiated fast-reactor fuel pin cladding specimens at heating rates of 10 0 F/s (5.6 0 K/s) and 200 0 F/s (111 0 K/s) to generate mechanical property information for use in describing cladding behavior during off-normal events. Mechanical property data were then analyzed, applying the Larson-Miller Parameter to the effects of heating rate and neutron fluence. Data from simulated transient tests on TREAT-tested fuel pins demonstrate that Plant Protective System termination of 3$/s transients prevents significant damage to cladding. The breach opening produced during simulated transient testing is shown to decrease in size with increasing neutron fluence

  4. Rhenium Mechanical Properties and Joining Technology

    Science.gov (United States)

    Reed, Brian D.; Biaglow, James A.

    1996-01-01

    Iridium-coated rhenium (Ir/Re) provides thermal margin for high performance and long life radiation cooled rockets. Two issues that have arisen in the development of flight Ir/Re engines are the sparsity of rhenium (Re) mechanical property data (particularly at high temperatures) required for engineering design, and the inability to directly electron beam weld Re chambers to C103 nozzle skirts. To address these issues, a Re mechanical property database is being established and techniques for creating Re/C103 transition joints are being investigated. This paper discusses the tensile testing results of powder metallurgy Re samples at temperatures from 1370 to 2090 C. Also discussed is the evaluation of Re/C103 transition pieces joined by both, explosive and diffusion bonding. Finally, the evaluation of full size Re transition pieces, joined by inertia welding, as well as explosive and diffusion bonding, is detailed.

  5. Mechanical properties of intra-ocular lenses

    Science.gov (United States)

    Ehrmann, Klaus; Kim, Eon; Parel, Jean-Marie

    2008-02-01

    Cataract surgery usually involves the replacement of the natural crystalline lens with a rigid or foldable intraocular lens to restore clear vision for the patient. While great efforts have been placed on optimising the shape and optical characteristics of IOLs, little is know about the mechanical properties of these devices and how they interact with the capsular bag once implanted. Mechanical properties measurements were performed on 8 of the most commonly implanted IOLs using a custom build micro tensometer. Measurement data will be presented for the stiffness of the haptic elements, the buckling resistance of foldable IOLs, the dynamic behaviour of the different lens materials and the axial compressibility. The biggest difference between the lens types was found between one-piece and 3-piece lenses with respect to the flexibility of the haptic elements

  6. Evaluation of mechanical properties of esthetic brackets

    OpenAIRE

    Matsui, Shigeyuki; Umezaki, Eisaku; Komazawa, Daigo; Otsuka, Yuichiro; Suda, Naoto

    2015-01-01

    Plastic brackets, as well as ceramic brackets, are used in various cases since they have excellent esthetics. However, their mechanical properties remain uncertain. The purpose of this study was to determine how deformation and stress distribution in esthetic brackets differ among materials under the same wire load. Using the digital image correlation method, we discovered the following: (1) the strain of the wings of plastic brackets is within 0.2% and that of ceramic and metal brackets is n...

  7. Modeling the mechanical properties of DNA nanostructures.

    Science.gov (United States)

    Arbona, Jean Michel; Aimé, Jean-Pierre; Elezgaray, Juan

    2012-11-01

    We discuss generalizations of a previously published coarse-grained description [Mergell et al., Phys. Rev. E 68, 021911 (2003)] of double stranded DNA (dsDNA). The model is defined at the base-pair level and includes the electrostatic repulsion between neighbor helices. We show that the model reproduces mechanical and elastic properties of several DNA nanostructures (DNA origamis). We also show that electrostatic interactions are necessary to reproduce atomic force microscopy measurements on planar DNA origamis.

  8. Mechanical Properties of Additively Manufactured Thick Honeycombs

    Directory of Open Access Journals (Sweden)

    Reza Hedayati

    2016-07-01

    Full Text Available Honeycombs resemble the structure of a number of natural and biological materials such as cancellous bone, wood, and cork. Thick honeycomb could be also used for energy absorption applications. Moreover, studying the mechanical behavior of honeycombs under in-plane loading could help understanding the mechanical behavior of more complex 3D tessellated structures such as porous biomaterials. In this paper, we study the mechanical behavior of thick honeycombs made using additive manufacturing techniques that allow for fabrication of honeycombs with arbitrary and precisely controlled thickness. Thick honeycombs with different wall thicknesses were produced from polylactic acid (PLA using fused deposition modelling, i.e., an additive manufacturing technique. The samples were mechanically tested in-plane under compression to determine their mechanical properties. We also obtained exact analytical solutions for the stiffness matrix of thick hexagonal honeycombs using both Euler-Bernoulli and Timoshenko beam theories. The stiffness matrix was then used to derive analytical relationships that describe the elastic modulus, yield stress, and Poisson’s ratio of thick honeycombs. Finite element models were also built for computational analysis of the mechanical behavior of thick honeycombs under compression. The mechanical properties obtained using our analytical relationships were compared with experimental observations and computational results as well as with analytical solutions available in the literature. It was found that the analytical solutions presented here are in good agreement with experimental and computational results even for very thick honeycombs, whereas the analytical solutions available in the literature show a large deviation from experimental observation, computational results, and our analytical solutions.

  9. Measurement of material mechanical properties in microforming

    Science.gov (United States)

    Yun, Wang; Xu, Zhenying; Hui, Huang; Zhou, Jianzhong

    2006-02-01

    As the rapid market need of micro-electro-mechanical systems engineering gives it the wide development and application ranging from mobile phones to medical apparatus, the need of metal micro-parts is increasing gradually. Microforming technology challenges the plastic processing technology. The findings have shown that if the grain size of the specimen remains constant, the flow stress changes with the increasing miniaturization, and also the necking elongation and the uniform elongation etc. It is impossible to get the specimen material properties in conventional tensile test machine, especially in the high precision demand. Therefore, one new measurement method for getting the specimen material-mechanical property with high precision is initiated. With this method, coupled with the high speed of Charge Coupled Device (CCD) camera and high precision of Coordinate Measuring Machine (CMM), the elongation and tensile strain in the gauge length are obtained. The elongation, yield stress and other mechanical properties can be calculated from the relationship between the images and CCD camera movement. This measuring method can be extended into other experiments, such as the alignment of the tool and specimen, micro-drawing process.

  10. Characterization of Mechanical Properties of Microbial Biofilms

    Science.gov (United States)

    Callison, Elizabeth; Gose, James; Perlin, Marc; Ceccio, Steven

    2017-11-01

    The physical properties of microbial biofilms grown subject to shear flows determine the form and mechanical characteristics of the biofilm structure, and consequently, the turbulent interactions over and through the biofilm. These biofilms - sometimes referred to as slime - are comprised of microbial cells and extracellular polymeric substance (EPS) matrices that surround the multicellular communities. Some of the EPSs take the form of streamers that tend to oscillate in flows, causing increased turbulent mixing and drag. As the presence of EPS governs the compliance and overall stability of the filamentous streamers, investigation of the mechanical properties of biofilms may also inform efforts to understand hydrodynamic performance of fouled systems. In this study, a mixture of four diatom genera was grown under turbulent shear flow on test panels. The mechanical properties and hydrodynamic performance of the biofilm were investigated using rheology and turbulent flow studies in the Skin-Friction Flow Facility at the University of Michigan. The diatoms in the mixture of algae were identified, and the elastic and viscous moduli were determined from small-amplitude oscillations, while a creep test was used to evaluate the biofilm compliance.

  11. Improved Prediction of Blood-Brain Barrier Permeability Through Machine Learning with Combined Use of Molecular Property-Based Descriptors and Fingerprints.

    Science.gov (United States)

    Yuan, Yaxia; Zheng, Fang; Zhan, Chang-Guo

    2018-03-21

    Blood-brain barrier (BBB) permeability of a compound determines whether the compound can effectively enter the brain. It is an essential property which must be accounted for in drug discovery with a target in the brain. Several computational methods have been used to predict the BBB permeability. In particular, support vector machine (SVM), which is a kernel-based machine learning method, has been used popularly in this field. For SVM training and prediction, the compounds are characterized by molecular descriptors. Some SVM models were based on the use of molecular property-based descriptors (including 1D, 2D, and 3D descriptors) or fragment-based descriptors (known as the fingerprints of a molecule). The selection of descriptors is critical for the performance of a SVM model. In this study, we aimed to develop a generally applicable new SVM model by combining all of the features of the molecular property-based descriptors and fingerprints to improve the accuracy for the BBB permeability prediction. The results indicate that our SVM model has improved accuracy compared to the currently available models of the BBB permeability prediction.

  12. Crack modelling for the assessment of stiffness loss of reinforced concrete structures under mechanical loading - determination of the permeability of the micro-cracked body; Modelisation de la fissuration pour l'evaluation de la perte d'etancheite des structures en beton arme sous chargements mecaniques

    Energy Technology Data Exchange (ETDEWEB)

    Bongue Boma, M

    2007-12-15

    We propose a model describing the evolution of mechanical and permeability properties of concrete under slow mechanical loading. Calling upon the theory of continua with microstructure, the kinematic of the domain is enriched by a variable characterising size and orientation of the crack field. We call upon configurational forces to deal with crack propagation and we determine the balance equations governing both strain and propagation. The geometry of the microstructure is representative of the porous media: the permeability is obtained from the resolution of Stokes equations in an elementary volume. An example has been treated: we considered simple assumptions (uniform crack field, application of linear fracture mechanics...) and we determined the behaviour of a body under tensile loading. Strain, crack propagation and stiffness loss are completely assessed. Finally the evolution of permeability is plotted: once activated, crack propagation is the main cause of water tightness loss. (author)

  13. Crack modelling for the assessment of stiffness loss of reinforced concrete structures under mechanical loading - determination of the permeability of the micro-cracked body; Modelisation de la fissuration pour l'evaluation de la perte d'etancheite des structures en beton arme sous chargements mecaniques

    Energy Technology Data Exchange (ETDEWEB)

    Bongue Boma, M

    2007-12-15

    We propose a model describing the evolution of mechanical and permeability properties of concrete under slow mechanical loading. Calling upon the theory of continua with microstructure, the kinematic of the domain is enriched by a variable characterising size and orientation of the crack field. We call upon configurational forces to deal with crack propagation and we determine the balance equations governing both strain and propagation. The geometry of the microstructure is representative of the porous media: the permeability is obtained from the resolution of Stokes equations in an elementary volume. An example has been treated: we considered simple assumptions (uniform crack field, application of linear fracture mechanics...) and we determined the behaviour of a body under tensile loading. Strain, crack propagation and stiffness loss are completely assessed. Finally the evolution of permeability is plotted: once activated, crack propagation is the main cause of water tightness loss. (author)

  14. Measuring Mechanical Properties Of Optical Glasses

    Science.gov (United States)

    Tucker, Dennis S.; Nichols, Ronald L.

    1989-01-01

    Report discusses mechanical tests measuring parameters of strength and fracture mechanics of optical glasses. To obtain required tables of mechanical properties of each glass of interest, both initial-strength and delayed-fracture techniques used. Modulus of rupture measured by well-known four-point bending method. Initial bending strength measured by lesser-known double-ring method, in which disk of glass supported on one face near edge by larger ring and pressed on its other face by smaller concentric ring. Method maximizes stress near center, making it more likely specimen fractures there, and thereby suppresses edge effects. Data from tests used to predict reliabilities and lifetimes of glass optical components of several proposed spaceborne instruments.

  15. Mechanical Properties of Nanofilled Polypropylene Composites

    Directory of Open Access Journals (Sweden)

    Cristina-Elisabeta PELIN

    2015-06-01

    Full Text Available The paper presents a study concerning mechanical performance of thermoplastic nanocomposites based on isotactic polypropylene matrix, nanofilled with montmorillonite modified with quaternary ammonium salt and carboxyl functionalized carbon nanotubes, respectively, added in the same concentration relative to the matrix. The nanofilled and single polymer materials were obtained by simple melt compounding through extrusion process followed by injection molding into specific shape specimens for mechanical testing of the samples. Mechanical properties were evaluated by tensile and 3 point bending tests. In terms of modulus of elasticity, the results showed overall positive effects concerning the effect of nanofiller addition to the thermoplastic polymer. The fracture cross section of the tested specimens was characterized by FT-IR spectroscopy and SEM microscopy.

  16. Drug permeability and mucoadhesion properties of thiolated trimethyl chitosan nanoparticles in oral insulin delivery.

    Science.gov (United States)

    Yin, Lichen; Ding, Jieying; He, Chunbai; Cui, Liming; Tang, Cui; Yin, Chunhua

    2009-10-01

    Trimethyl chitosan-cysteine conjugate (TMC-Cys) was synthesized in an attempt to combine the mucoadhesion and the permeation enhancing effects of TMC and thiolated polymers related to different mechanisms for oral absorption. TMC-Cys with various molecular weights (30, 200, and 500 kDa) and quaternization degrees (15 and 30%) was allowed to form polyelectrolyte nanoparticles with insulin through self-assembly, which demonstrated particle size of 100-200 nm, zeta potential of +12 to +18 mV, and high encapsulation efficiency. TMC-Cys/insulin nanoparticles (TMC-Cys NP) showed a 2.1-4.7-fold increase in mucoadhesion compared to TMC/insulin nanoparticles (TMC NP), which might be partly attributed to disulfide formation between TMC-Cys and mucin as evidenced by DSC measurement. Compared to insulin solution and TMC NP, TMC-Cys NP induced increased insulin transport through rat intestine by 3.3-11.7 and 1.7-2.6 folds, promoted Caco-2 cell internalization by 7.5-12.7 and 1.7-3.0 folds, and augmented uptake in Peyer's patches by 14.7-20.9 and 1.7-5.0 folds, respectively. Such results were further confirmed by in vivo experiment with the optimal TMC-Cys NP. Biocompatibility assessment revealed lack of toxicity of TMC-Cys NP. Therefore, self-assembled nanoparticles between TMC-Cys and protein drugs could be an effective and safe oral delivery system.

  17. Mechanical properties of ion implanted ceramic surfaces

    International Nuclear Information System (INIS)

    Burnett, P.J.

    1985-01-01

    This thesis investigates the mechanisms by which ion implantation can affect those surface mechanical properties of ceramics relevant to their tribological behaviour, specifically hardness and indentation fracture. A range of model materials (including single crystal Si, SiC, A1 2 0 3 , Mg0 and soda-lime-silica glass) have been implanted with a variety of ion species and at a range of ion energies. Significant changes have been found in both low-load microhardness and indentation fracture behaviour. The changes in hardness have been correlated with the evolution of an increasingly damaged and eventually amorphous thin surface layer together with the operation of radiation-, solid-solution- and precipitation-hardening mechanisms. Compressive surface stresses have been shown to be responsible for the observed changes in identation fracture behaviour. In addition, the levels of surface stress present have been correlated with the structure of the surface layer and a simple quantitative model proposed to explain the observed stress-relief upon amorphisation. Finally, the effects of ion implantation upon a range of polycrystalline ceramic materials has been investigated and the observed properties modifications compared and contrasted to those found for the model single crystal materials. (author)

  18. Effect of fortification with various types of milk proteins on the rheological properties and permeability of nonfat set yogurt.

    Science.gov (United States)

    Peng, Y; Serra, M; Horne, D S; Lucey, J A

    2009-01-01

    Yogurt base was prepared from reconstituted skim milk powder (SMP) with 2.5% protein and fortified with additional 1% protein (wt/wt) from 4 different milk protein sources: SMP, milk protein isolate (MPI), micellar casein (MC), and sodium caseinate (NaCN). Heat-treated yogurt mixes were fermented at 40 degrees C with a commercial yogurt culture until pH 4.6. During fermentation pH was monitored, and storage modulus (G') and loss tangent (LT) were measured using dynamic oscillatory rheology. Yield stress (sigma(yield)) and permeability of gels were analyzed at pH 4.6. Addition of NaCN significantly reduced buffering capacity of yogurt mix by apparently solubilizing part of the indigenous colloidal calcium phosphate (CCP) in reconstituted SMP. Use of different types of milk protein did not affect pH development except for MC, which had the slowest fermentation due to its very high buffering. NaCN-fortified yogurt had the highest G' and sigma(yield) values at pH 4.6, as well as maximum LT values. Partial removal of CCP by NaCN before fermentation may have increased rearrangements in yogurt gel. Soluble casein molecules in NaCN-fortified milks may have helped to increase G' and LT values of yogurt gels by increasing the number of cross-links between strands. Use of MC increased the CCP content but resulted in low G' and sigma(yield) at pH 4.6, high LT and high permeability. The G' value at pH 4.6 of yogurts increased in the order: SMP = MC yogurt. Practical Application: In yogurt processing, it is common to add additional milk solids to improve viscosity and textural attributes. There are many different types of milk protein powders that could potentially be used for fortification purposes. This study suggests that the type of milk protein used for fortification impacts yogurt properties and sodium caseinate gave the best textural results.

  19. Mechanical Properties of Nylon Harp Strings

    Science.gov (United States)

    Lynch-Aird, Nicolas; Woodhouse, Jim

    2017-01-01

    Monofilament nylon strings with a range of diameters, commercially marketed as harp strings, have been tested to establish their long-term mechanical properties. Once a string had settled into a desired stress state, the Young’s modulus was measured by a variety of methods that probe different time-scales. The modulus was found to be a strong function of testing frequency and also a strong function of stress. Strings were also subjected to cyclical variations of temperature, allowing various thermal properties to be measured: the coefficient of linear thermal expansion and the thermal sensitivities of tuning, Young’s modulus and density. The results revealed that the particular strings tested are divided into two groups with very different properties: stress-strain behaviour differing by a factor of two and some parametric sensitivities even having the opposite sign. Within each group, correlation studies allowed simple functional fits to be found to the key properties, which have the potential to be used in automated tuning systems for harp strings. PMID:28772858

  20. Mechanical Properties of Nylon Harp Strings

    Directory of Open Access Journals (Sweden)

    Nicolas Lynch-Aird

    2017-05-01

    Full Text Available Monofilament nylon strings with a range of diameters, commercially marketed as harp strings, have been tested to establish their long-term mechanical properties. Once a string had settled into a desired stress state, the Young’s modulus was measured by a variety of methods that probe different time-scales. The modulus was found to be a strong function of testing frequency and also a strong function of stress. Strings were also subjected to cyclical variations of temperature, allowing various thermal properties to be measured: the coefficient of linear thermal expansion and the thermal sensitivities of tuning, Young’s modulus and density. The results revealed that the particular strings tested are divided into two groups with very different properties: stress-strain behaviour differing by a factor of two and some parametric sensitivities even having the opposite sign. Within each group, correlation studies allowed simple functional fits to be found to the key properties, which have the potential to be used in automated tuning systems for harp strings.

  1. PICA Variants with Improved Mechanical Properties

    Science.gov (United States)

    Thornton, Jeremy; Ghandehari, Ehson M.; Fan, Wenhong; Stackpoole, Margaret; Chavez-Garcia, Jose

    2011-01-01

    Phenolic Impregnated Carbon Ablator (PICA) is a member of the family of Lightweight Ceramic Ablators (LCAs) and was developed at NASA Ames Research Center as a thermal protection system (TPS) material for the Stardust mission probe that entered the Earth s atmosphere faster than any other probe or vehicle to date. PICA, carbon fiberform base and phenolic polymer, shows excellent thermal insulative properties at heating rates from about 250 W/sq cm to 1000 W/sq cm. The density of standard PICA - 0.26 g/cu cm to 0.28 g/cu cm - can be changed by changing the concentration of the phenolic resin. By adding polymers to the phenolic resin before curing it is possible to significantly improve the mechanical properties of PICA without significantly increasing the density.

  2. Design and mechanical properties of insect cuticle.

    Science.gov (United States)

    Vincent, Julian F V; Wegst, Ulrike G K

    2004-07-01

    Since nearly all adult insects fly, the cuticle has to provide a very efficient and lightweight skeleton. Information is available about the mechanical properties of cuticle-Young's modulus of resilin is about 1 MPa, of soft cuticles about 1 kPa to 50 MPa, of sclerotised cuticles 1-20 GPa; Vicker's Hardness of sclerotised cuticle ranges between 25 and 80 kgf mm(-2); density is 1-1.3 kg m(-3)-and one of its components, chitin nanofibres, the Young's modulus of which is more than 150 GPa. Experiments based on fracture mechanics have not been performed although the layered structure probably provides some toughening. The structural performance of wings and legs has been measured, but our understanding of the importance of buckling is lacking: it can stiffen the structure (by elastic postbuckling in wings, for example) or be a failure mode. We know nothing of fatigue properties (yet, for instance, the insect wing must undergo millions of cycles, flexing or buckling on each cycle). The remarkable mechanical performance and efficiency of cuticle can be analysed and compared with those of other materials using material property charts and material indices. Presented in this paper are four: Young's modulus-density (stiffness per unit weight), specific Young's modulus-specific strength (elastic hinges, elastic energy storage per unit weight), toughness-Young's modulus (fracture resistance under various loading conditions), and hardness (wear resistance). In conjunction with a structural analysis of cuticle these charts help to understand the relevance of microstructure (fibre orientation effects in tendons, joints and sense organs, for example) and shape (including surface structure) of this fibrous composite for a given function. With modern techniques for analysis of structure and material, and emphasis on nanocomposites and self-assembly, insect cuticle should be the archetype for composites at all levels of scale.

  3. Water permeability, hybrid layer long-term integrity and reaction mechanism of a two-step adhesive system.

    Science.gov (United States)

    Grégoire, Geneviève; Dabsie, Firas; Delannée, Mathieu; Akon, Bernadette; Sharrock, Patrick

    2010-07-01

    Our aim was to investigate the reaction mechanism of formation of the hybrid layer by a HEMA-containing self-etch adhesive and to study fluid filtration, contact angle and interfacial ultrastructure by SEM following a 1 year ageing period. Acidic behaviour and chemical interactions between Silorane System Adhesive and dentine were studied by potentiometric titrations, atomic absorption spectroscopy and infrared spectroscopy. The hydrophilicity of the adhesive was evaluated using the sessile drop method and dentine permeability by hydraulic conductance. The morphological study of the dentine/adhesive system interface was conducted using SEM. The Silorane System Adhesive behaved as a multi-acid with several different pK(a) values. When the adhesive was in contact with dentine, the acid was progressively consumed and calcium ions were released. The acrylate substituted phosphonate bound strongly to apatite crystals. The polyacrylic acid copolymer reacted with calcium ions and formed an interpenetrating polymer network (IPN). Water contact angle measurements showed rapid spreading on primer (angles reached 15 degrees at 30s) and larger contact angles when the Silorane bonding layer was added (from over 60 degrees to 44 degrees ). A thick, homogeneous hybrid layer was observed both initially and after 1 year of ageing, with a corresponding hydraulic conductance of -48.50% initially and -52.07% at 12 months. The Silorane System Adhesive is capable of both dissolving calcium ions and binding to apatite surfaces. The results showed the hydrophilicity of the adhesive, which formed an IPN-like hybrid layer that conserved adequate impermeability over a 1-year period. Copyright 2010 Elsevier Ltd. All rights reserved.

  4. Mechanical properties of irradiated rubber-blends

    International Nuclear Information System (INIS)

    Nasr, G.M.; Madani, M.

    2005-01-01

    A study has been made on blend ratios of natural rubber (NR) and acrylonitrile butadiene rubber (NBR) that are loaded with general purpose furnace (GPE) carbon black and irradiated at different gamma radiation doses. It was fount that the mechanical properties of such blend are highly affected by γ- irradiation dose and the composition ratios of its constituents. The elongation at break for blends was found to increase slightly with increasing NBR loafing which is mainly due to the stiffness of blending matrix formation between NR and GPF carbon black particles. The hysteresis loss, extension ratio and shape factor have been calculated for the different un-irradiated and irradiated samples

  5. Effects of irradiation on mechanical properties

    International Nuclear Information System (INIS)

    Server, W.L.; Griesbach, T.J.; Dragunov, Y.; Amaev, A.

    1998-01-01

    As a result of the popularity of the Agencies report 'Neutron Irradiation Embrittlement of Reactor Pressure Vessel Steels' of 1975, it was decided that another report on this broad subject would be of use. In this report, background and contemporary views on specially identified areas of the subject are considered as self-contained chapters, written by experts. The effects of irradiation on the mechanical properties of reactor pressure vessel steels are explained. This chapter provides some background on the critical elements controlling neutron damage effects. Distinction is made between vessels made in the USA and in the former USSR

  6. Mechanical properties of phosphorene nanoribbons and oxides

    International Nuclear Information System (INIS)

    Hao, Feng; Chen, Xi

    2015-01-01

    Mechanical properties of phosphorene nanoribbons and oxides are investigated by using density functional theory. It is found that the ideal strength of nanoribbon decreases in comparison with that of 2D phosphorene. The Young's modulus of armchair nanoribbon has a remarkable size effect because of the edge relaxations. The analysis of the stress-strain relation indicates that, owing to chemisorbed oxygen atoms, the ideal strength and Young's modulus of 2D phosphorene oxide are greatly reduced along the zigzag direction, especially upon high oxidation ratios. In addition, strain and oxidation have significant impacts on phonon dispersion

  7. Mechanical properties of low dimensional materials

    Science.gov (United States)

    Saini, Deepika

    Recent advances in low dimensional materials (LDMs) have paved the way for unprecedented technological advancements. The drive to reduce the dimensions of electronics has compelled researchers to devise newer techniques to not only synthesize novel materials, but also tailor their properties. Although micro and nanomaterials have shown phenomenal electronic properties, their mechanical robustness and a thorough understanding of their structure-property relationship are critical for their use in practical applications. However, the challenges in probing these mechanical properties dramatically increase as their dimensions shrink, rendering the commonly used techniques inadequate. This dissertation focuses on developing techniques for accurate determination of elastic modulus of LDMs and their mechanical responses under tensile and shear stresses. Fibers with micron-sized diameters continuously undergo tensile and shear deformations through many phases of their processing and applications. Significant attention has been given to their tensile response and their structure-tensile properties relations are well understood, but the same cannot be said about their shear responses or the structure-shear properties. This is partly due to the lack of appropriate instruments that are capable of performing direct shear measurements. In an attempt to fill this void, this dissertation describes the design of an inexpensive tabletop instrument, referred to as the twister, which can measure the shear modulus (G) and other longitudinal shear properties of micron-sized individual fibers. An automated system applies a pre-determined twist to the fiber sample and measures the resulting torque using a sensitive optical detector. The accuracy of the instrument was verified by measuring G for high purity copper and tungsten fibers. Two industrially important fibers, IM7 carbon fiber and KevlarRTM 119, were found to have G = 17 and 2.4 GPa, respectively. In addition to measuring the shear

  8. Mechanical properties of phosphorene nanoribbons and oxides

    Energy Technology Data Exchange (ETDEWEB)

    Hao, Feng [Department of Earth and Environmental Engineering, Columbia University, New York, New York 10027 (United States); Chen, Xi, E-mail: xichen@columbia.edu [International Center for Applied Mechanics, SV Laboratory, School of Aerospace, Xi' an Jiaotong University, Xi' an 710049 (China); Department of Earth and Environmental Engineering, Columbia University, New York, New York 10027 (United States)

    2015-12-21

    Mechanical properties of phosphorene nanoribbons and oxides are investigated by using density functional theory. It is found that the ideal strength of nanoribbon decreases in comparison with that of 2D phosphorene. The Young's modulus of armchair nanoribbon has a remarkable size effect because of the edge relaxations. The analysis of the stress-strain relation indicates that, owing to chemisorbed oxygen atoms, the ideal strength and Young's modulus of 2D phosphorene oxide are greatly reduced along the zigzag direction, especially upon high oxidation ratios. In addition, strain and oxidation have significant impacts on phonon dispersion.

  9. Analysis of Mechanical Properties for GEM Foil

    CERN Document Server

    Chin, Yuk Ming

    2016-01-01

    In view of new assembly technique of the GEM detector; in which three foils stack is stretched to get the uniform gaps among the foils. We studied the mechanical properties of the foil material. We conditioned the samples in different environments to make them extra dry and wet. As holes are the major source of the charge amplification their deformation can effect the detector performance. Therefore in our studies we also studied at which level of the stress the holes deformation is seen. These tensile and holes deformation studies can help to optimize the stress during detector assembly.

  10. Antimicrobial, Physicochemical, Mechanical, and Barrier Properties of Tapioca Starch Films Incorporated with Eucalyptus Extract

    Directory of Open Access Journals (Sweden)

    M. Rojhan

    2013-11-01

    Full Text Available Starch is found in abundance in nature and it is one of the raw materials used for food packagingbecause of the low price, biodegradability, good mechanical and barrier properties. The recycling ability ofcoating materials was significantly increased by using edible films and coating in comparison to traditionalpackaging and it could be an alternative for synthetic films. In this research, the effect of eucalyptus extract(Aqueous Extract was investigated on tapioca starch films. Tapioca starch films were prepared by castingmethod with addition of eucalyptus extract and a mixture of sorbitol/glycerol (weight ratio of 3 to 1 asplasticizers. Eucalyptus extract incorporated to the tapioca starch films were dried at different concentrations(0, 15, 25, and 35 of total solid under controlled conditions. Physicochemical properties such as waterabsorption capacity (WAC, water vapor permeability (WVP and mechanical properties of the films wereevaluated. Results showed that by increasing the concentration of eucalyptus extract, tensile strength wasincreased from 20.60 to 15.68 (MPa, also elongation was increased from 19.31 to 23.57 (% at break andYoung’s modulus was decreased from 800.31 to 500.32 (MPa. Also incorporation of eucalyptus extract in thestructure of biopolymer increased permeability of water vapor of starch films. Tapioca starch filmsincorporated with eucalyptus extract exhibited excellent antimicrobial activity against E. Coli. In summary,eucalyptus extract improves functional properties of tapioca starch films and this types of films can be used infood packaging.

  11. Estimating the Permeability of Carbonate Rocks from the Fractal Properties of Moldic Pores using the Kozeny-Carman Equation

    Directory of Open Access Journals (Sweden)

    Adewale Amosu

    2018-02-01

    Full Text Available Reservoir modeling of carbonate rocks requires a proper understanding of the pore space distribution and its relationship to permeability. Using a pigeonhole fractal model we characterize the fractal geometry of moldic pore spaces and extract the fractal dimension. We apply the Kozeny-Carman equation and equations relating the tortuosity and the porosity to the fractal dimension to derive an empirical relationship between permeability and porosity.

  12. Dynamic mechanical properties of toughened polyamide composites

    International Nuclear Information System (INIS)

    Alsewailem, Fares D.

    2008-01-01

    The effect of incorporating thermoplastic rubber on the dynamic mechanical properties, storage and loss moduli, of virgin and recycled glass-fiber-reinforced polyamide 66 has been investigated in this study. Styrene-Ethylene-Styrene and Ethylene-Propylene grafted with maleic anhydride were used as elastomers for toughening. Dynamic mechanical properties of the composites were examined by the rotational rhometry. Shear storage and loss moduli of recycled and virgin materials were measured against frequency. Also the variation of storage modulus of the virgin composites was measured against temperatures by conducting a series of torsion tests. Both dynamic storage and loss moduli of the composites were found to increase with increasing glass fiber and rubber contents. Recycled composites had lower values of dynamic modulus compared that of virgin composites; however by proper combining of fiber and rubber into the recycled material, its modulus fairly matches that of the virgin material. Addition of rubber to virgin composites causes a reduction in G' as temperature increases. Rubber, which acts as a stress concentrator, had a major effect on minimizing the overall modulus of the composites. The in G' versus temperature has been observed for all composites: however the temperature at which the transition G' occurs decreases with increasing rubber content. (author)

  13. Mechanical properties of polymer-modified porous concrete

    Science.gov (United States)

    Ariffin, N. F.; Jaafar, M. F. Md.; Shukor Lim, N. H. Abdul; Bhutta, M. A. R.; Hussin, M. W.

    2018-04-01

    In this research work, polymer-modified porous concretes (permeable concretes) using polymer latex and redispersible polymer powder with water-cement ratio of 30 %, polymer-cement ratios of 0 to 10 % and cement content of 300 kg/m3 are prepared. The porous concrete was tested for compressive strength, flexural strength, water permeability and void ratio. The cubes size of specimen is 100 mm ×100 mm × 100 mm and 150 mm × 150 mm × 150 mm while the beam size is 100 mm × 100 mm × 500 mm was prepared for particular tests. The tests results show that the addition of polymer as a binder to porous concrete gives an improvement on the strength properties and coefficient of water permeability of polymer-modified porous concrete. It is concluded from the test results that increase in compressive and flexural strengths and decrease in the coefficient of water permeability of the polymer-modified porous concrete are clearly observed with increasing of polymer-cement ratio.

  14. Mechanical properties of the beetle elytron, a biological composite material

    Science.gov (United States)

    We determined the relationship between composition and mechanical properties of elytral (modified forewing) cuticle of the beetles Tribolium castaneum and Tenebrio molitor. Elytra of both species have similar mechanical properties at comparable stages of maturation (tanning). Shortly after adult ecl...

  15. Water exchange and permeability properties of the skin in three species of amphibious sea snakes (Laticauda spp.).

    Science.gov (United States)

    Lillywhite, H B; Menon, J G; Menon, G K; Sheehy, C M; Tu, M C

    2009-06-01

    Evolutionary transitions between different environmental media such as air and water pose special problems with respect to skin permeability because of the dramatic changes in the driving gradients and nature of water exchange processes. Also, during the transitional periods prior to complete adaptation to a new medium, the skin is exposed to two very different sets of environmental conditions. Here, we report new data for transepidermal evaporative water loss (TEWL) and cutaneous resistance to evaporative water loss (R(s)) of sea snakes that are transitional in the sense of being amphibious and semi-terrestrial. We investigated three species of sea kraits (Elapidae: Laticaudinae) that are common to Orchid Island (Lanyu), Taiwan. Generally, R(s) of all three species is lower than that characteristic of terrestrial/xeric species of snakes measured in other taxa. Within Laticauda, R(s) is significantly greater (TEWL lower) in the more terrestrial species and lowest (TEWL highest) in the more aquatic species. Previously reported losses of water from snakes kept in seawater exhibit a reversed trend, with lower rates of loss in the more aquatic species. These data suggest selection for adaptive traits with respect to increasing exposure to the marine environment. Thus, a countergradient of traits is reflected in decreased TEWL in aerial environments and decreased net water efflux in marine environments, acting simultaneously in the three species. The pattern for TEWL correlates with ultrastructural evidence for increased lipogenesis in the stratum corneum of the more terrestrial species. The skin surfaces of all three species are hydrophobic. Species differences in this property possibly explain the pattern for water efflux when these snakes are in seawater, which remains to be investigated.

  16. Characterisation and monitoring of the Excavation Disturbed Zone (EDZ) in fractured gneisses of the Roselend underground laboratory: permeability measurements, transport property changes and related radon bursts

    Science.gov (United States)

    Wassermann, Jérôme; Sabroux, Jean-Christophe; Richon, Patrick; Pontreau, Sébastien; Guillon, Sophie; Pili, Eric

    2010-05-01

    pressure measurements between an obturated borehole and the tunnel is conducted to monitor the possible modifications of the transport properties of the EDZ due to hydraulical and/or mechanical sollicitations of the nearby Roselend reservoir lake. As radon level is controlled by emanation and transport path through the medium. The observed bursts of radon should be due to changes of the radon transport properties (Trique et al. 1999) of the EDZ. A correlation between the differential pressure variations and radon bursts is clearly observed. Radon bursts seem to be related to overpressure events that take place in the instrumented borehole. Which external sollicitations, hydraulical or mechanical, or both, induce such a behaviour? References Bossart, P., Meier, P. M., Moeri, A., Trick, T., and J.-C. Mayor (2002). Geological and hydraulic characterisation of the excavation disturbed zone in the Opalinus Clay of the Mont Terri Rock Laboratory, Engineering Geology, 66, 19-38. Dezayes, C., and T. Villemin (2002). Etat de la fracturation dans la galerie CEA de Roselend et analyse de la déformation cassante dans le massif du Méraillet, technical report, Lab. de Geodyn. de Chaisnes Alp., Univ. de Savoie, Savoie, France. Jakubick, A. T., and T. Franz (1993). Vacuum testing of the permeability of the excavation damaged zone, Rock Mech. Rock Engng., 26(2), 165-182. Patriarche, D., Pili, E., Adler, P. M., and J.-F. Thovert (2007). Stereological analysis of fractures in the Roselend tunnel and permeability determination, Water Resour. Res., 43, W09421. Richon, P., Perrier, F., Sabroux, J.-C., Trique, M., Ferry, C., Voisin, V., and E. Pili (2004). Spatial and time variations of radon-222 concentration in the atmosphere of a dead-end horizontal tunnel, J. Environ. Radioact., 78, 179-198. Richon, P., Perrier, F., Pili, E., and J.-C. Sabroux (2009). Detectability and significance of the 12hr barometric tide in radon-222 signal, dripwater flow rate, air temperature and carbon dioxide

  17. Intestinal Permeability: The Basics

    Directory of Open Access Journals (Sweden)

    Ingvar Bjarnason

    1995-01-01

    Full Text Available The authors review some of the more fundamental principles underlying the noninvasive assessment of intestinal permeability in humans, the choice of test markers and their analyses, and the practical aspects of test dose composition and how these can be changed to allow the specific assessment of regional permeability changes and other intestinal functions. The implications of increased intestinal permeability in the pathogenesis of human disease is discussed in relation to findings in patients with Crohn’s disease. A common feature of increased intestinal permeability is the development of a low grade enteropathy, and while quantitatively similar changes may be found in Crohn’s disease these seem to predict relapse of disease. Moreover, factors associated with relapse of Crohn’s disease have in common an action to increase intestinal permeability. While increased intestinal permeability does not seem to be important in the etiology of Crohn’s disease it may be a central mechanism in the clinical relapse of disease.

  18. Safety, efficacy, and molecular mechanism of claudin-1-specific peptides to enhance blood-nerve-barrier permeability.

    Science.gov (United States)

    Sauer, Reine-Solange; Krug, Susanne M; Hackel, Dagmar; Staat, Christian; Konasin, Natalia; Yang, Shaobing; Niedermirtl, Benedikt; Bosten, Judith; Günther, Ramona; Dabrowski, Sebastian; Doppler, Kathrin; Sommer, Claudia; Blasig, Ingolf E; Brack, Alexander; Rittner, Heike L

    2014-07-10

    The blood-nerve barrier consists of the perineurium and endoneurial vessels. The perineurial barrier is composed of a basal membrane and a layer of perineurial cells sealed by tight junction proteins preventing e.g. application of analgesics for selective regional pain control. One of the barrier-sealing proteins in the blood-nerve barrier is claudin-1. Therefore, the claudin-1-peptidomimetics (C1C2), derived from the first extracellular loop (ECL1) on claudin-1 was developed. In this study, we further evaluated the expression of tight junction proteins in the perineurium in Wistar rats and characterized the specificity, in vivo applicability, mechanism of action as well as the biocompatibility of C1C2. In the perineurium, claudin-19, tricellulin and ZO-1, but no claudin-2, 3, 8 and -11 were expressed. C1C2 specifically bound to the ECL1 of claudin-1 and fluorescent 5,6-carboxytetramethylrhodamine-C1C2 was rapidly internalized. Opening the perineurium with C1C2 reduced the mRNA and protein expression of claudin-1 and increased small and macromolecule permeability into the peripheral nerve. Application of C1C2 facilitated regional analgesia using μ-opioid receptor agonists like DAMGO or morphine without motor impairment in naïve rats as well as rats with hind paw inflammation. In contrast the control peptide C2C2 derived from ECL1 on claudin-2 did neither open the barrier nor facilitated opioid-mediated regional analgesia. C1C2 delivery was well tolerated and caused no morphological and functional nerve damage. C1C2 effects could be reversed by interference with the wnt-signal-transduction pathway, specifically the homeobox transcription factor cdx2, using a glycogen-synthase-kinase-3 inhibitor. In summary, we describe the composition of and a pathway to open the perineurial barrier employing a peptide to deliver hydrophilic substances to the peripheral nerve. Copyright © 2014 Elsevier B.V. All rights reserved.

  19. Teletactile System Based on Mechanical Properties Estimation

    Directory of Open Access Journals (Sweden)

    Mauro M. Sette

    2011-01-01

    Full Text Available Tactile feedback is a major missing feature in minimally invasive procedures; it is an essential means of diagnosis and orientation during surgical procedures. Previous works have presented a remote palpation feedback system based on the coupling between a pressure sensor and a general haptic interface. Here a new approach is presented based on the direct estimation of the tissue mechanical properties and finally their presentation to the operator by means of a haptic interface. The approach presents different technical difficulties and some solutions are proposed: the implementation of a fast Young’s modulus estimation algorithm, the implementation of a real time finite element model, and finally the implementation of a stiffness estimation approach in order to guarantee the system’s stability. The work is concluded with an experimental evaluation of the whole system.

  20. Mechanical Properties of Graphene-Rubber Nanocomposites

    Science.gov (United States)

    Anhar, N. A. M.; Ramli, M. M.; Hambali, N. A. M. A.; Aziz, A. A.; Mat Isa, S. S.; Danial, N. S.; Abdullah, M. M. A. B.

    2017-11-01

    This research focused on development of wearable sensor device by using Prevulcanized Natural Rubber (PV) and Epoxidized Natural Rubber (ENR 50) latex incorporated with graphene oxide (GO), graphene paste, graphene powder and reduced graphene oxide (rGO) powder. The compounding formulation and calculation were based on phr (parts per hundred rubber) and all the samples were then tested for mechanical properties using Instron 5565 machine. It was found that the sonication effects on tensile strength may have better quality of tensile strength compared to non-sonicated GO. For PV incorporate GO, the optimum loading was best determined at loading 1.5 phr with or without sonication and similar result was recorded for PV/G. For ENR 50 incorporate graphene paste and rGO powder nanocomposite shows the best optimum was at 3.0 phr with 24 hours’ sonication.

  1. Mechanical properties on geopolymer brick: A review

    Science.gov (United States)

    Deraman, L. M.; Abdullah, M. M. A.; Ming, L. Y.; Ibrahim, W. M. W.; Tahir, M. F. M.

    2017-09-01

    Bricks has stand for many years as durable construction substantial, especially in the area of civil engineering to construct buildings. Brick commonly used in the structure of buildings as a construction wall, cladding, facing perimeter, paving, garden wall and flooring. The contribution of ordinary Portland cement (OPC) in cement bricks production worldwide to greenhouse gas emissions. Due to this issue, some researchers have done their study with other materials to produce bricks, especially as a by-product material. Researchers take effort in this regard to synthesizing from by-product materials such as fly ash, bottom ash and kaolin that are rich in silicon and aluminium in the development of inorganic alumina-silicate polymer, called geopolymer Geopolymer is a polymerization reaction between various aluminosilicate oxides with silicates solution or alkali hydroxide solution forming polymerized Si-O-Al-O bonds. This paper summarized some research finding of mechanical properties of geopolymer brick using by-product materials.

  2. Evaluation of mechanical properties of esthetic brackets.

    Science.gov (United States)

    Matsui, Shigeyuki; Umezaki, Eisaku; Komazawa, Daigo; Otsuka, Yuichiro; Suda, Naoto

    2015-01-01

    Plastic brackets, as well as ceramic brackets, are used in various cases since they have excellent esthetics. However, their mechanical properties remain uncertain. The purpose of this study was to determine how deformation and stress distribution in esthetic brackets differ among materials under the same wire load. Using the digital image correlation method, we discovered the following: (1) the strain of the wings of plastic brackets is within 0.2% and that of ceramic and metal brackets is negligible, (2) polycarbonate brackets having a stainless steel slot show significantly smaller displacement than other plastic brackets, and (3) there is a significant difference between plastic brackets and ceramic and stainless steel brackets in terms of the displacement of the bracket wing.

  3. Material modeling of biofilm mechanical properties.

    Science.gov (United States)

    Laspidou, C S; Spyrou, L A; Aravas, N; Rittmann, B E

    2014-05-01

    A biofilm material model and a procedure for numerical integration are developed in this article. They enable calculation of a composite Young's modulus that varies in the biofilm and evolves with deformation. The biofilm-material model makes it possible to introduce a modeling example, produced by the Unified Multi-Component Cellular Automaton model, into the general-purpose finite-element code ABAQUS. Compressive, tensile, and shear loads are imposed, and the way the biofilm mechanical properties evolve is assessed. Results show that the local values of Young's modulus increase under compressive loading, since compression results in the voids "closing," thus making the material stiffer. For the opposite reason, biofilm stiffness decreases when tensile loads are imposed. Furthermore, the biofilm is more compliant in shear than in compression or tension due to the how the elastic shear modulus relates to Young's modulus. Copyright © 2014 Elsevier Inc. All rights reserved.

  4. Mechanical properties of porous PNZT polycrystalline ceramics

    International Nuclear Information System (INIS)

    Biswas, D.R.; Fulrath, R.M.

    1977-08-01

    Niobium-doped lead zirconate-titanate (PNZT) was used to investigate the effect of porosity on the mechanical properties of a polycrystalline ceramic. Spherical pores (110 to 150 μm diameter) were introduced by using organic materials in the initial specimen fabrication. The matrix grain size (2 to 5 μm) was kept constant. Small pores (2 to 3 μm diameter) of the order of the grain size were formed by varying the sintering conditions. The effect of porosity on strength was predicted quite well by Weibull's probabilistic approach. The Young's modulus showed a linear relationship with increase in porosity. A decrease in fracture toughness with increase in porosity was also observed. It was found that at equivalent porosities, small pore specimens gave higher strength, Young's modulus and fracture toughness compared to specimens containing large pores. Fracture surface analysis, by scanning electron microscopy, showed fracture originated either at the tensile surface or at the edge of the specimen

  5. Mechanical properties of ceramic-polymer nanocomposites

    Directory of Open Access Journals (Sweden)

    2009-03-01

    Full Text Available Nano crystalline powders of Barium Sodium Niobate (BNN with the composition Ba3–2x Na4+x R Nb10 O30 with (R stands for rare earth = 0, x = 0 have been prepared by conventional ceramic technique. Barium Sodium Niobate can form a wide range of solid solutions, incorporating rare earth and alkali, alkaline earth elements with different compositions. The powder belonged to tungsten bronze type structure with tetragonal symmetry and lattice constants a = b = 1.2421 nm and c = 0.3903 nm. XRD (X-ray Diffraction SEM (Scanning Electron Microscope and AFM (Atomic Force Microscope studies revealed that the particle size is in the nanometer range. Composites are prepared by mixing powders of BNN with polystyrene at different volume fractions of the BNN. Melt mixing technique is carried out in a Brabender Plasticoder at a rotor speed of 60 rpm (rotations per minute for composite preparation. Mechanical properties such as stress-strain behavior, Young’s modulus, tensile strength, strain at break etc. are evaluated. Addition of filler enhances the mechanical properties of the polymer such as Young’s modulus and tensile strength. The composites showed the trend of perfect adhesion between the filler and the polymer. The filler particles are distributed relatively uniform fashion in all composites and the particles are almost spherical in shape with irregular boundaries. To explore more carefully the degree of interfacial adhesion between the two phases, the results are analyzed by using models featuring adhesion parameter. The experimental results are compared with theoretical predictions.

  6. Mechanical properties of nanostructure of biological materials

    Science.gov (United States)

    Ji, Baohua; Gao, Huajian

    2004-09-01

    Natural biological materials such as bone, teeth and nacre are nanocomposites of protein and mineral with superior strength. It is quite a marvel that nature produces hard and tough materials out of protein as soft as human skin and mineral as brittle as classroom chalk. What are the secrets of nature? Can we learn from this to produce bio-inspired materials in the laboratory? These questions have motivated us to investigate the mechanics of protein-mineral nanocomposite structure. Large aspect ratios and a staggered alignment of mineral platelets are found to be the key factors contributing to the large stiffness of biomaterials. A tension-shear chain (TSC) model of biological nanostructure reveals that the strength of biomaterials hinges upon optimizing the tensile strength of the mineral crystals. As the size of the mineral crystals is reduced to nanoscale, they become insensitive to flaws with strength approaching the theoretical strength of atomic bonds. The optimized tensile strength of mineral crystals thus allows a large amount of fracture energy to be dissipated in protein via shear deformation and consequently enhances the fracture toughness of biocomposites. We derive viscoelastic properties of the protein-mineral nanostructure and show that the toughness of biocomposite can be further enhanced by the viscoelastic properties of protein.

  7. Biodegradable compounds: Rheological, mechanical and thermal properties

    Science.gov (United States)

    Nobile, Maria Rossella; Lucia, G.; Santella, M.; Malinconico, M.; Cerruti, P.; Pantani, R.

    2015-12-01

    Recently great attention from industry has been focused on biodegradable polyesters derived from renewable resources. In particular, PLA has attracted great interest due to its high strength and high modulus and a good biocompatibility, however its brittleness and low heat distortion temperature (HDT) restrict its wide application. On the other hand, Poly(butylene succinate) (PBS) is a biodegradable polymer with a low tensile modulus but characterized by a high flexibility, excellent impact strength, good thermal and chemical resistance. In this work the two aliphatic biodegradable polyesters PBS and PLA were selected with the aim to obtain a biodegradable material for the industry of plastic cups and plates. PBS was also blended with a thermoplastic starch. Talc was also added to the compounds because of its low cost and its effectiveness in increasing the modulus and the HDT of polymers. The compounds were obtained by melt compounding in a single screw extruder and the rheological, mechanical and thermal properties were investigated. The properties of the two compounds were compared and it was found that the values of the tensile modulus and elongation at break measured for the PBS/PLA/Talc compound make it interesting for the production of disposable plates and cups. In terms of thermal resistance the compounds have HDTs high enough to contain hot food or beverages. The PLA/PBS/Talc compound can be, then, considered as biodegradable substitute for polystyrene for the production of disposable plates and cups for hot food and beverages.

  8. Permeability measuremens of brazilian Eucalyptus

    Directory of Open Access Journals (Sweden)

    Marcio Rogério da Silva

    2010-09-01

    Full Text Available The permeability of Brazilian Eucalyptus grandis and Eucalyptus citriodora wood was measured in a custom build gas analysis chamber in order to determine which species could be successfully treated with preservatives. Liquid permeability was tested using an emulsion of Neen oil and a control of distillated water. Air was used to test the gas phase permeability. For both Eucalyptus grandis and Eucalyptus citriodora, the longitudinal permeability of gas was shown to be about twice as great as the liquid phase permeability. No radial permeability was observed for either wood. The permeability of air and water through the sapwood of Eucalyptus grandis was greater than that through the sapwood of Eucalyptus citriodora. The permeability of neen oil preservative through the sapwood of Eucalyptus grandis was also greater than through the sapwood of E. Citradora, but the difference was not statistically significant. Scanning Electron Microscopy images showed that the distribution and obstruction in the vessels could be correlated with observed permeability properties. Irrespective of the causes of differences in permeability between the species, the fluid phase flux through the sapwood of both species was significant, indicating that both Eucalyptus grandis and Eucalyptus citriodora could be successfully treated with wood preservative.

  9. Effect of antimicrobial on mechanical, barrier and optical properties of corn starch based self-supporting edible film

    Directory of Open Access Journals (Sweden)

    Tanima Chowdhury

    2013-10-01

    Full Text Available Antimicrobials like potassium sorbate, sodium propionate, and benzoic acid were incorporated in corn starch based formulation to investigate their effect on mechanical, water vapour barrier and optical properties of the developed self supporting edible film. The film was prepared by casting technique. When incorporated at 1.40% and above, potassium sorbate decreased the tensile strength (about 22% and increased the elongation (about 55% of control film; whereas, it increased the water vapour permeability by 15% only when added at 2.66%. At 2.66%, benzoic acid reduced the tensile strength by 24% and sodium propionate increased elongation by 17%. These two antimicrobials did not change the water vapour permeability. However, all the three antimicrobials adversely affected the optical properties by decreasing the whiteness index, increasing yellowness index, and reducing the surface gloss, with potassium sorbate showing the maximum effect. Among the three antimicrobials, sodium propionate appeared to be the best with minimum deterioration of film properties.

  10. Variability of mechanical properties of nuclear pressure vessel steels

    International Nuclear Information System (INIS)

    Petrequin, P.; Soulat, P.

    1980-01-01

    Causes of variability of mechanical properties nuclear pressure vessel steels are reviewed and discussed. The effects of product shape and size, processing history and heat treatment are investigated. Some quantitative informations are given on the scatter of mechanical properties of typical pressure vessel components. The necessity of using recommended or standardized properties for comparing mechanical properties before and after irradiation in pin pointed. (orig.) [de

  11. High energy radiation effects on mechanical properties of butyl rubber compounds

    International Nuclear Information System (INIS)

    Pozenato, Cristina A.; Scagliusi, Sandra R.; Cardoso, Elisabeth C.L.; Lugao, Ademar B.

    2013-01-01

    The high energy radiation on butyl rubber compounds causes a number of chemical reactions that occur after initial ionization and excitation events. These reactions lead to changes in molecular mass of the polymer through scission and crosslinking of the molecules, being able to affect the physical and mechanical properties. Butyl rubber has excellent mechanical properties and oxidation resistance as well as low gas and water vapor permeability. Due to all these properties butyl rubber is widely used industrially and particularly in tires manufacturing. In accordance with various authors, the major effect of high energy, such as gamma rays in butyl rubber, is the yielding of free-radicals along with changes in mechanical properties. There were evaluated effects imparted from high energy radiation on mechanical properties of butyl rubber compounds, non-irradiated and irradiated with 25 kGy, 50 kGy, 150 kGy and 200 kGy. It was also observed a sharp reducing in stress rupture and elongation at break for doses higher than 50 kGy, pointing toward changes in polymeric chain along build-up of free radicals and consequent degradation. (author)

  12. Controlling DC permeability in cast steels

    International Nuclear Information System (INIS)

    Sumner, Aaran; Gerada, Chris; Brown, Neil; Clare, Adam

    2017-01-01

    Annealing (at multiple cooling rates) and quenching (with tempering) was performed on specimens of cast steel of varying composition. The aim was to devise a method for selecting the steel with the highest permeability, from any given range of steels, and then increasing the permeability by heat treatment. Metallographic samples were imaged using optical microscopy to show the effect of the applied heat treatments on the microstructure. Commonly cast steels can have DC permeability altered by the careful selection of a heat treatment. Increases of up to 381% were achieved by annealing using a cooling rate of 6.0 °C/min. Annealing was found to cause the carbon present in the steel to migrate from grain boundaries and from within ferrite crystals into adjacent pearlite crystals. The migration of the carbon resulted in less carbon at grain boundaries and within ferrite crystals reducing the number of pinning sites between magnetic domains. This gives rise to a higher permeability. Quenching then tempering was found to cause the formation of small ferrite crystals with the carbon content of the steel predominately held in the martensitic crystal structures. The results show that with any given range of steel compositions the highest baseline DC permeability will be found with the steel that has the highest iron content and the lowest carbon content. For the samples tested in this paper a cooling rate of 4.5 °C/min resulted in the relative permeability of the sample with the highest baseline permeability, AS4, increasing from 783 to 1479 at 0.5 T. This paper shows how heat treatments commonly applied to hypoeutectoid cast steels, to improve their mechanical performance, can be used to also enhance electromagnetic properties of these alloys. The use of cast steels allows the creation of DC components for electrical machines not possible by the widely used method of stacking of electrical grade sheet steels. - Highlights: • A range of structural steels had their

  13. Controlling DC permeability in cast steels

    Energy Technology Data Exchange (ETDEWEB)

    Sumner, Aaran, E-mail: aaran.sumner@nottingham.ac.uk [University of Nottingham, Nottingham University Park Campus, Nottingham NG7 2RD, England (United Kingdom); Gerada, Chris, E-mail: chris.gerada@nottingham.ac.uk [Electrical Machines, University of Nottingham, Tower Building, Nottingham NG7 2RD, England (United Kingdom); Brown, Neil, E-mail: neil.brown@cummins.com [Advanced Electrical Machines Research and Technology at Cummins Power Generation, Peterborough PE2 6FZ, England (United Kingdom); Clare, Adam, E-mail: adam.clare@nottingham.ac.uk [Advanced Manufacturing, University of Nottingham, University Park Campus, Nottingham NG7 2RD, England (United Kingdom)

    2017-05-01

    Annealing (at multiple cooling rates) and quenching (with tempering) was performed on specimens of cast steel of varying composition. The aim was to devise a method for selecting the steel with the highest permeability, from any given range of steels, and then increasing the permeability by heat treatment. Metallographic samples were imaged using optical microscopy to show the effect of the applied heat treatments on the microstructure. Commonly cast steels can have DC permeability altered by the careful selection of a heat treatment. Increases of up to 381% were achieved by annealing using a cooling rate of 6.0 °C/min. Annealing was found to cause the carbon present in the steel to migrate from grain boundaries and from within ferrite crystals into adjacent pearlite crystals. The migration of the carbon resulted in less carbon at grain boundaries and within ferrite crystals reducing the number of pinning sites between magnetic domains. This gives rise to a higher permeability. Quenching then tempering was found to cause the formation of small ferrite crystals with the carbon content of the steel predominately held in the martensitic crystal structures. The results show that with any given range of steel compositions the highest baseline DC permeability will be found with the steel that has the highest iron content and the lowest carbon content. For the samples tested in this paper a cooling rate of 4.5 °C/min resulted in the relative permeability of the sample with the highest baseline permeability, AS4, increasing from 783 to 1479 at 0.5 T. This paper shows how heat treatments commonly applied to hypoeutectoid cast steels, to improve their mechanical performance, can be used to also enhance electromagnetic properties of these alloys. The use of cast steels allows the creation of DC components for electrical machines not possible by the widely used method of stacking of electrical grade sheet steels. - Highlights: • A range of structural steels had their

  14. Effect of Nanosilica Particle Size on the Water Permeability, Abrasion Resistance, Drying Shrinkage, and Repair Work Properties of Cement Mortar Containing Nano-SiO2

    Directory of Open Access Journals (Sweden)

    Sattawat Haruehansapong

    2017-01-01

    Full Text Available This work presents the effect of nanosilica particle sizes on durability properties and repair work properties of cement mortar containing nanosilica (NS. Three different NS particle sizes of 12, 20, and 40 nm were used and compared with those of cement mortar without NS and cement mortar with silica fume (SF. Interesting results were obtained in which the particle size of NS affected directly the abrasion resistance and water permeability. NS with particle size of 40 nm is the optimum size and gave the highest abrasion resistance and water permeability. For repair work properties, cement mortars containing NS (12 and 20 nm and SF experienced higher drying shrinkage than that of cement mortar without NS and then presented cracking behavior and debonding between the cement mortars and concrete substrate. Cement mortar containing 40 nm of NS gave the lowest drying shrinkage, the lowest crack number, and the highest adhesive strength. These results indicate that the particle size of NS affected not only the durability properties but also the repair work properties of cement mortar.

  15. Mechanical properties and fracture of titanium hydrides

    International Nuclear Information System (INIS)

    Koketsu, Hideyuki; Taniyama, Yoshihiro; Yonezu, Akio; Cho, Hideo; Ogawa, Takeshi; Takemoto, Mikio; Nakayama, Gen

    2006-01-01

    Titanium hydrides tend to suffer fracture when their thicknesses reach a critical thickness. Morphology and mechanical property of the hydrides are, however, not well known. The study aims to reveal the hydride morphology and fracture types of the hydrides. Chevron shaped plate hydrides were found to be produced on the surface of pure titanium (Grade 1) and Grade 7 titanium absorbing hydrogen. There were tree types of fracture of the hydrides, i.e., crack in hydride layer, exfoliation of the layer and shear-type fracture of the hydride plates, during the growth of the hydrides and deformation. We next estimated the true stress-strain curves of the hydrides on Grade 1 and 7 titanium using the dual Vickers indentation method, and the critical strain causing the Mode-I fine crack by indentation. Fracture strength and strain of the hydrides in Grade 1 titanium were estimated as 566 MPa and 4.5%, respectively. Those of the hydride in Grade 7 titanium were 498 MPa and 16%. Though the fracture strains estimated from the plastic instability of true stress-strain curves were approximately the half of those estimated by finite element method, the titanium hydrides were estimated to possess some extent of toughness or plastic deformation capability. (author)

  16. CW 316 mechanical properties during thermal transients

    International Nuclear Information System (INIS)

    Cauvin, R.; Boutard, J.L.; Allegraud, G.

    1984-06-01

    During in pile incidents, the cladding can experience higher temperatures than the nominal one; it is necessary to know the mechanical properties of the cladding material during such thermal transients to predict the time and location of rupture. Two types of tests have been developed: first tensile (constant strain rate) tests after a heating at a constant rate and secondly constant load tests where heating is performed until rupture occurs. The tensile tests clearly show the role of the heating rate: the higher is the heating rate, the lower is the cold work recovery. Constant load tests were conducted with either uniaxial or biaxial (burst tests) loading. The same stress/failure temperature relation is found in both types of loading using the Von Mises equivalent stress. To predict failure, the Larson Miller parameter is not adequate, as well as all parameters based on a time/temperature equivalence. The yield stress measured in the two types of tests are very different probably due to a strain rate effect. Indeed the tensile tests are dynamic ones to avoid thermal recovery during the test duration, while the strain rate measured in constant load tests ranges only from 10 -5 s -1 to 10 -3 s -1 , being an increasing function of heating rate (ranging from 1 0 c/s to 100 0 c/s)

  17. Mechanical properties of JPDR biological shield concrete

    International Nuclear Information System (INIS)

    Idei, Yoshio; Kamata, Hiroshi; Akutsu, Youichi; Onizawa, Kunio; Nakajima, Nobuya; Sukegawa, Takenori; Kakizaki, Masayoshi.

    1990-11-01

    Plant life of nuclear power plant will be determined by the aging degradation of main components and structures because of the difficulty and the cost of the replacement. These components are the reactor pressure vessel, concrete structures and cables. Authors have performed the investigation of JPDR biological shield which was the succeeded in first generating electricity in Japan and is now being decommissioned in JAERI. The test core samples were bored from the shield concrete and tested to obtain the mechanical properties. Test results are summarized as below, (1) Peak value of fast neutron dose was estimated as 1 x 10 18 n/cm 2 which is equivalent to the dose at the end of life for commercial power reactor. (2) Averaged compressive strength of all specimens had been increased about 20 % compared with initial design strength. (3) It was identified that the compressive strength had a little trend to increase with the increase of neutron dose within the dose range obtained in this study. (4) Tensile strength, Elastic modulus and Poisson's ratio showed little effect of neutron dose. (5) It was suggested that the inside and the mid-section liners were effective to keep the water in concrete and to avoid the reduction in strength. (author)

  18. The mechanism of coking pressure generation I: Effect of high volatile matter coking coal, semi-anthracite and coke breeze on coking pressure and plastic coal layer permeability

    Energy Technology Data Exchange (ETDEWEB)

    Seiji Nomura; Merrick Mahoney; Koichi Fukuda; Kenji Kato; Anthony Le Bas; Sid McGuire [Nippon Steel Corporation, Chiba (Japan). Environment and Process Technology Center

    2010-07-15

    One of the most important aspects of the cokemaking process is to control and restrain the coking pressure since excessive coking pressure tends to lead to operational problems and oven wall damage. Therefore, in order to understand the mechanism of coking pressure generation, the permeability of the plastic coal layer and the coking pressure for the same single coal and the same blended coal were measured and the relationship between them was investigated. Then the 'inert' (pressure modifier) effect of organic additives such as high volatile matter coking coal, semi-anthracite and coke breeze was studied. The coking pressure peak for box charging with more uniform bulk density distribution was higher than that for top charging. It was found that the coking pressure peaks measured at different institutions (NSC and BHPBilliton) by box charging are nearly the same. The addition of high volatile matter coking coal, semi-anthracite and coke breeze to a low volatile matter, high coking pressure coal greatly increased the plastic layer permeability in laboratory experiments and correspondingly decreased the coking pressure. It was found that, high volatile matter coking coal decreases the coking pressure more than semi-anthracite at the same plastic coal layer permeability, which indicates that the coking pressure depends not only on plastic coal layer permeability but also on other factors. Coking pressure is also affected by the contraction behavior of the coke layer near the oven walls and a large contraction decreases the coal bulk density in the oven center and hence the internal gas pressure in the plastic layer. The effect of contraction on coking pressure needs to be investigated further. 33 refs., 18 figs., 5 tabs.

  19. Mechanical Properties of Moringa ( Moringa oleifera ) Seeds in ...

    African Journals Online (AJOL)

    Mechanical properties are very important in the design of machines and the analysis of the behaviour of products during agricultural processing. In this research work, the mechanical properties of Moringa were determined as design parameters for the development of an oil expeller for the crop. The properties were the ...

  20. Mechanical and Thermal Properties of the AH of FRW Universe

    International Nuclear Information System (INIS)

    Yi-Huan, Wei

    2010-01-01

    We calculate the work made out by the apparent horizon (AH) of the Friedmann–Robertson–Walker (FRW) universe and the heat flux through the AH from the first law of thermodynamics. We discuss the mechanical properties of the AH and analyze the universe model for which the mechanical properties can change. Finally, the thermal properties of the AH of FRW universe are discussed

  1. Effect of temperature on the permeability of gas adsorbed coal under triaxial stress conditions

    Science.gov (United States)

    Li, Xiangchen; Yan, Xiaopeng; Kang, Yili

    2018-04-01

    The combined effects of gas sorption, stress and temperature play a significant role in the changing behavior of gas permeability in coal seams. The effect of temperature on nitrogen and methane permeability of naturally fractured coal is investigated. Coal permeability, P-wave velocity and axial strain were simultaneously measured under two effective stresses and six different temperatures. The results showed that the behavior of nitrogen and methane permeability presented nonmonotonic changes with increasing temperature. The variation in the P-wave velocity and axial strain showed a good correspondence with coal permeability. A higher effective stress limited the bigger deformation and caused the small change in permeability. Methane adsorption and desorption significantly influence the mechanical properties of coal and play an important role in the variations in coal permeability. The result of coal permeability during a complete stress-strain process showed that the variation in permeability is determined by the evolution of the internal structure. The increase in the temperature of the gas saturated coal causes the complex interaction between matrix swelling, matrix shrinkage and micro-fracture generation, which leads to the complex changes in coal structure and permeability. These results are helpful to understand the gas transport mechanism for exploiting coal methane by heat injection.

  2. Physicochemical and Mechanical Properties of Bambara Groundnut Starch Films Modified with Stearic Acid.

    Science.gov (United States)

    Oyeyinka, Samson A; Singh, Suren; Amonsou, Eric O

    2017-01-01

    The physicochemical and mechanical properties of biofilm prepared from bambara starch modified with varying concentrations of stearic acid (0%, 2.5%, 3.5%, 5%, 7%, and 10%) were studied. By scanning electron microscopy, bambara starch films modified with stearic acid (≥3.5%) showed a progressively rough surface compared to those with 2.5% stearic acid and the control. Fourier transform infrared spectroscopy spectra revealed a peak shift of approximately 31 cm -1 , suggesting the promotion of hydrogen bond formation between hydroxyl groups of starch and stearic acid. The addition of 2.5% stearic acid to bambara starch film reduced water vapor permeability by approximately 17%. Bambara starch films modified with higher concentration of stearic acid were more opaque and showed significantly high melting temperatures. However, mechanical properties of starch films were generally negatively affected by stearic acid. Bambara starch film may be modified with 2.5% stearic acid for improved water vapor permeability and thermal stability with minimal effect on tensile strength. © 2016 Institute of Food Technologists®.

  3. Mango kernel starch-gum composite films: Physical, mechanical and barrier properties.

    Science.gov (United States)

    Nawab, Anjum; Alam, Feroz; Haq, Muhammad Abdul; Lutfi, Zubala; Hasnain, Abid

    2017-05-01

    Composite films were developed by the casting method using mango kernel starch (MKS) and guar and xanthan gums. The concentration of both gums ranged from 0% to 30% (w/w of starch; db). Mechanical properties, oxygen permeability (OP), water vapor permeability (WVP), solubility in water and color parameters of composite films were evaluated. The crystallinity and homogeneity between the starch and gums were also evaluated by X-ray diffraction (XRD) and scanning electron microscopy (SEM). The scanning electron micrographs showed homogeneous matrix, with no signs of phase separation between the components. XRD analysis demonstrated diminished crystalline peak. Regardless of gum type the tensile strength (TS) of composite films increased with increasing gum concentration while reverse trend was noted for elongation at break (EAB) which found to be decreased with increasing gum concentration. The addition of both guar and xanthan gums increased solubility and WVP of the composite films. However, the OP was found to be lower than that of the control with both gums. Furthermore, addition of both gums led to changes in transparency and opacity of MKS films. Films containing 10% (w/w) xanthan gum showed lower values for solubility, WVP and OP, while film containing 20% guar gum showed good mechanical properties. Copyright © 2017 Elsevier B.V. All rights reserved.

  4. Mechanisms for development of property rights institutions

    Directory of Open Access Journals (Sweden)

    Žarković Jelena

    2006-01-01

    Full Text Available The institution of property rights is increasingly recognized as an essential building block of an economically prosperous society. The question that remains unsolved, however, is how do we develop effective property rights institutions? The literature dealing with the development of property rights tends to be, in general, an optimistic one since there is a tendency to view the design of property rights institutions as maximizing decisions to economize on transaction costs and to facilitate new economic activities. On the other hand, since property rights define the distribution of wealth and political power in a society, changes in property rights structures are likely to be influenced by more than pure efficiency considerations. Therefore, in order to achieve a balanced analysis of the evolution of property rights institutions, the model of endogenous property rights creation should be modified. We did that by introducing the neoinstitutional theory of the state in the model.

  5. Study of anisotropic mechanical properties for aeronautical PMMA

    Directory of Open Access Journals (Sweden)

    Wei Shang

    Full Text Available For the properties of polymer are relative to its structure, the main purpose of the present work is to investigate the mechanical properties of the aeronautical PMMA which has been treated by the directional tensile technology. Isodyne images reveal the stress state in directional PMMA. And then, an anisotropic mechanical model is established. Furthermore, all mechanical parameters are measured by the digital image correlation method. Finally, based on the anisotropic mechanical model and mechanical parameters, the FEM numerical simulation and experimental methods are applied to analyze the fracture mechanical properties along different directions.

  6. Cartilage-like mechanical properties of poly (ethylene glycol)-diacrylate hydrogels.

    Science.gov (United States)

    Nguyen, Quynhhoa T; Hwang, Yongsung; Chen, Albert C; Varghese, Shyni; Sah, Robert L

    2012-10-01

    Hydrogels prepared from poly-(ethylene glycol) (PEG) have been used in a variety of studies of cartilage tissue engineering. Such hydrogels may also be useful as a tunable mechanical material for cartilage repair. Previous studies have characterized the chemical and mechanical properties of PEG-based hydrogels, as modulated by precursor molecular weight and concentration. Cartilage mechanical properties vary substantially, with maturation, with depth from the articular surface, in health and disease, and in compression and tension. We hypothesized that PEG hydrogels could mimic a broad range of the compressive and tensile mechanical properties of articular cartilage. The objective of this study was to characterize the mechanical properties of PEG hydrogels over a broad range and with reference to articular cartilage. In particular, we assessed the effects of PEG precursor molecular weight (508 Da, 3.4 kDa, 6 kDa, and 10 kDa) and concentration (10-40%) on swelling property, equilibrium confined compressive modulus (H(A0)), compressive dynamic stiffness, and hydraulic permeability (k(p0)) of PEG hydrogels in static/dynamic confined compression tests, and equilibrium tensile modulus (E(ten)) in tension tests. As molecular weight of PEG decreased and concentration increased, hydrogels exhibited a decrease in swelling ratio (31.5-2.2), an increase in H(A0) (0.01-2.46 MPa) and E(ten) (0.02-3.5 MPa), an increase in dynamic compressive stiffness (0.055-42.9 MPa), and a decrease in k(p0) (1.2 × 10(-15) to 8.5 × 10(-15) m(2)/(Pa s)). The frequency-dependence of dynamic compressive stiffness amplitude and phase, as well as the strain-dependence of permeability, were typical of the time- and strain-dependent mechanical behavior of articular cartilage. H(A0) and E(ten) were positively correlated with the final PEG concentration, accounting for swelling. These results indicate that PEG hydrogels can be prepared to mimic many of the static and dynamic mechanical

  7. Comparison of Tensile, Permeability and Color Properties of Starch-based Bionanocomposites Containing Two Types of Fillers: Sodium Montmorilonite and Cellulose Nanocrystal

    Directory of Open Access Journals (Sweden)

    Nooshin Noushirvani

    2013-01-01

    Full Text Available The objective of this research was to compare the tensile, permeability, solubility and color properties of plasticized starch-polyvinyl alcohol-Montmo-rillonite (PS-PVA-MMT and plasticized starch-polyvinyl alcohol-cellulose nanocrystal (PS-PVA-NCC bionanocomposite flms. The results showed that adding MMT (7%, increased the ultimate tensile strenght from 4.2 MPa to 4.61 MPa, however, NCC (7% did not show signifcant (p < 0.5 effect on the ultimate tensile strength. Addition of MMT decreased while NCC  increased  the  strain-to-break of  the flms. The solubility in water decreased from 23.56% to 18.77% and 11.75% for the flms containing NCC and MMT, respectively. Similarly, water vapor permeability value of 7.41 ×10-7 g/m.h.Pa was dropped to 7.05×10-7 g/m.h.Pa and 6.19×10-7 g/m.h.Pa in flms containing NCC and MMT, respectively. The results showed that the effects of MMT on tensile and permeability were higher than NCC, which can be attributed to differences in the structure and hydrophilicity of two nanoparticles.

  8. Effect of a pulsed magnetic field on permeability of the cornea and sorption properties of the tissue structures and refractive media of the eye

    International Nuclear Information System (INIS)

    Skrinnik, A.V.

    1986-01-01

    The author attempts to obtain direct proof of increased permeability of the cornea and enhanced sorption properties of the tissue structures and refractive media of the eye under the influence of a pulsed magnetic field (MF). In the course of the investigation, the method of radioactive indication of two substances ( 35 S-streptomycin and 75 Se-methionine), widely used in opthalmologic practice, was used. The radioactivity of the working solution of the preparations was 300,000 cpm in 0.1 ml. Changes in the permeability of the cornea were assessed on the basis of changes in radioactivity of the aqueous humor. The concentration of 35 S-streptomycin in aqueous humor of the animals immediately after exposure to MF was significantly higher than in the control. Analysis of permeability of the cornea for 75 Se-methionine also showed increased penetration of radioactivity into the aqueous. The results are evidence of the greater penetrating power of 75 Se-methionine

  9. Mechanism of mucosal permeability enhancement of CriticalSorb® (Solutol® HS15) investigated in vitro in cell cultures.

    Science.gov (United States)

    Shubber, Saif; Vllasaliu, Driton; Rauch, Cyril; Jordan, Faron; Illum, Lisbeth; Stolnik, Snjezana

    2015-02-01

    CriticalSorb™, with the principal component Solutol® HS15, is a novel mucosal drug delivery system demonstrated to improve the bioavailability of selected biotherapeutics. The intention of this study is to elucidate mechanism(s) responsible for the enhancement of trans-mucosal absorption of biological drugs by Solutol® HS15. Micelle size and CMC of Solutol® HS15 were determined in biologically relevant media. Polarised airway Calu-3 cell layers were used to measure the permeability of a panel of biological drugs, and to assess changes in TEER, tight junction and F-actin morphology. The rate of cell endocytosis was measured in vitro in the presence of Solutol® HS15 using a membrane probe, FM 2-10. This work initially confirms surfactant-like behaviour of Solutol® HS15 in aqueous media, while subsequent experiments demonstrate that the effect of Solutol® HS15 on epithelial tight junctions is different from a 'classical' tight junction opening agent and illustrate the effect of Solutol® HS15 on the cell membrane (endocytosis rate) and F-actin cytoskeleton. Solutol® HS15 is the principle component of CriticalSorb™ that has shown an enhancement in permeability of medium sized biological drugs across epithelia. This study suggests that its mechanism of action arises primarily from effects on the cell membrane and consequent impacts on the cell cytoskeleton in terms of actin organisation and tight junction opening.

  10. Microstructure, mechanical properties, bio-corrosion properties and antibacterial properties of Ti-Ag sintered alloys.

    Science.gov (United States)

    Chen, Mian; Zhang, Erlin; Zhang, Lan

    2016-05-01

    In this research, Ag element was selected as an antibacterial agent to develop an antibacterial Ti-Ag alloy by a powder metallurgy. The microstructure, phase constitution, mechanical properties, corrosion resistance and antibacterial properties of the Ti-Ag sintered alloys have been systematically studied by X-ray diffraction (XRD), scanning electron microscope (SEM), compressive test, electrochemical measurements and antibacterial test. The effects of the Ag powder size and the Ag content on the antibacterial property and mechanical property as well as the anticorrosion property have been investigated. The microstructure results have shown that Ti-Ag phase, residual pure Ag and Ti were the mainly phases in Ti-Ag(S75) sintered alloy while Ti2Ag was synthesized in Ti-Ag(S10) sintered alloy. The mechanical test indicated that Ti-Ag sintered alloy showed a much higher hardness and the compressive yield strength than cp-Ti but the mechanical properties were slightly reduced with the increase of Ag content. Electrochemical results showed that Ag powder size had a significant effect on the corrosion resistance of Ti-Ag sintered alloy. Ag content increased the corrosion resistance in a dose dependent way under a homogeneous microstructure. Antibacterial tests have demonstrated that antibacterial Ti-Ag alloy was successfully prepared. It was also shown that the Ag powder particle size and the Ag content influenced the antibacterial activity seriously. The reduction in the Ag powder size was benefit to the improvement in the antibacterial property and the Ag content has to be at least 3wt.% in order to obtain a strong and stable antibacterial activity against Staphylococcus aureus bacteria. The bacterial mechanism was thought to be related to the Ti2Ag and its distribution. Copyright © 2016 Elsevier B.V. All rights reserved.

  11. Some Physical and Mechanical Properties of Daniellia Ogea Harms ...

    African Journals Online (AJOL)

    ADOWIE PERE

    density were the physical properties tested while the mechanical properties were the modulus of rupture ... 300kN capacity of the food laboratory of the department of Agriculture of the University. ..... Negro, F; Cremonini, C; Zanuttini, R (2013).

  12. Nucleus geometry and mechanical properties of resistance spot ...

    Indian Academy of Sciences (India)

    Keywords. Automotive steels; resistance spot welding; mechanical properties; nucleus geometry. 1. .... High va- lues of hardness can be explained with martensitic forma- ... interface of DP450–DP600 steels may have stainless steel properties.

  13. Real-time observations of mechanical stimulus-induced enhancements of mechanical properties in osteoblast cells

    International Nuclear Information System (INIS)

    Zhang Xu; Liu Xiaoli; Sun Jialun; He Shuojie; Lee, Imshik; Pak, Hyuk Kyu

    2008-01-01

    Osteoblast, playing a key role in the pathophysiology of osteoporosis, is one of the mechanical stress sensitive cells. The effects of mechanical load-induced changes of mechanical properties in osteoblast cells were studied at real-time. Osteoblasts obtained from young Wister rats were exposed to mechanical loads in different frequencies and resting intervals generated by atomic force microscopy (AFM) probe tip and simultaneously measured the changes of the mechanical properties by AFM. The enhancement of the mechanical properties was observed and quantified by the increment of the apparent Young's modulus, E * . The observed mechanical property depended on the frequency of applied tapping loads. For the resting interval is 50 s, the mechanical load-induced enhancement of E * -values disappears. It seems that the enhanced mechanical property was recover able under no additional mechanical stimulus

  14. Mechanical properties of the human Achilles tendon, in vivo

    DEFF Research Database (Denmark)

    Kongsgaard, M; Nielsen, C H; Hegnsvad, S

    2011-01-01

    Ultrasonography has been widely applied for in vivo measurements of tendon mechanical properties. Assessments of human Achilles tendon mechanical properties have received great interest. Achilles tendon injuries predominantly occur in the tendon region between the Achilles-soleus myotendinous...... junction and Achilles-calcaneus osteotendinous junction i.e. in the free Achilles tendon. However, there has been no adequate ultrasound based method for quantifying the mechanical properties of the free human Achilles tendon. This study aimed to: 1) examine the mechanical properties of the free human...

  15. Additively manufactured metallic porous biomaterials based on minimal surfaces: A unique combination of topological, mechanical, and mass transport properties.

    Science.gov (United States)

    Bobbert, F S L; Lietaert, K; Eftekhari, A A; Pouran, B; Ahmadi, S M; Weinans, H; Zadpoor, A A

    2017-04-15

    Porous biomaterials that simultaneously mimic the topological, mechanical, and mass transport properties of bone are in great demand but are rarely found in the literature. In this study, we rationally designed and additively manufactured (AM) porous metallic biomaterials based on four different types of triply periodic minimal surfaces (TPMS) that mimic the properties of bone to an unprecedented level of multi-physics detail. Sixteen different types of porous biomaterials were rationally designed and fabricated using selective laser melting (SLM) from a titanium alloy (Ti-6Al-4V). The topology, quasi-static mechanical properties, fatigue resistance, and permeability of the developed biomaterials were then characterized. In terms of topology, the biomaterials resembled the morphological properties of trabecular bone including mean surface curvatures close to zero. The biomaterials showed a favorable but rare combination of relatively low elastic properties in the range of those observed for trabecular bone and high yield strengths exceeding those reported for cortical bone. This combination allows for simultaneously avoiding stress shielding, while providing ample mechanical support for bone tissue regeneration and osseointegration. Furthermore, as opposed to other AM porous biomaterials developed to date for which the fatigue endurance limit has been found to be ≈20% of their yield (or plateau) stress, some of the biomaterials developed in the current study show extremely high fatigue resistance with endurance limits up to 60% of their yield stress. It was also found that the permeability values measured for the developed biomaterials were in the range of values reported for trabecular bone. In summary, the developed porous metallic biomaterials based on TPMS mimic the topological, mechanical, and physical properties of trabecular bone to a great degree. These properties make them potential candidates to be applied as parts of orthopedic implants and/or as bone

  16. Mechanical properties of gamma-aluminium oxynitride

    NARCIS (Netherlands)

    Willems, H.X.; Hal, van P.F.; With, de G.; Metselaar, R.

    1993-01-01

    Mech. properties have been measured of three compositionally different types of g-aluminum oxynitride (Alon). The compns. corresponded to 67.5, 73 and 77.5 mol% Al2O3. To characterize the Alons, lattice parameters, densities, grain sizes and optical properties were measured. The measurements for the

  17. Thermal, electrochemical and mechanical properties of shape

    African Journals Online (AJOL)

    T. Ahmad

    2017-05-01

    May 1, 2017 ... C for 30 min with two pre-stressing conditions of straight and ... of nitinol mesh into technical fabric for examining it weaving properties as compared to ... nitinol wire showed better properties of weaving as compared to stainless steel. Ming et ... Phase transformation temperature was determined by DSC at a.

  18. Influence of various acids on the physico–mechanical properties of ...

    Indian Academy of Sciences (India)

    strength gain and hence slow reduction in permeability properties at early ages. ... For this reason the magnitude of low or high concentration can not be generalized. .... of soluble calcium salts due to the reaction of acids with cements.

  19. Experimental Analysis of Tensile Mechanical Properties of Sprayed FRP

    Directory of Open Access Journals (Sweden)

    Zhao Yang

    2016-01-01

    Full Text Available To study the tensile mechanical properties of sprayed FRP, 13 groups of specimens were tested through uniaxial tensile experiments, being analyzed about stress-strain curve, tensile strength, elastic modulus, breaking elongation, and other mechanical properties. Influencing factors on tensile mechanical properties of sprayed FRP such as fiber type, resin type, fiber volume ratio, fiber length, and composite thickness were studied in the paper too. The results show that both fiber type and resin type have an obvious influence on tensile mechanical properties of sprayed FRP. There will be a specific fiber volume ratio for sprayed FRP to obtain the best tensile mechanical property. The increase of fiber length can lead to better tensile performance, while that of composite thickness results in property degradation. The study can provide reference to popularization and application of sprayed FRP material used in structure reinforcement.

  20. Mechanical and Permeability Characteristics of Latex-Modified Pre-Packed Pavement Repair Concrete as a Function of the Rapid-Set Binder Content

    Directory of Open Access Journals (Sweden)

    Jae-Woong Han

    2015-10-01

    Full Text Available We evaluated the strength and durability characteristics of latex-polymer-modified, pre-packed pavement repair concrete (LMPPRC with a rapid-set binder. The rapid-set binder was a mixture of rapid-set cement and silica sand, where the fluidity was controlled using a latex polymer. The resulting mix exhibited a compressive strength of ¥21 MPa and a flexural strength of ¥3.5 MPa after 4 h of curing (i.e., the traffic opening term for emergency repairs of pavement. The ratio of latex polymer to rapid-set binder material was varied through 0.40, 0.33, 0.29, and 0.25. Mechanical characterization revealed that the mechanical performance, permeability, and impact resistance increased as the ratio of latex polymer to rapid-set binder decreased. The mixture exhibited a compressive strength of ¥21 MPa after 4 h when the ratio of latex polymer to rapid-set binder material was ¤0.29. The mixture exhibited a flexural strength of ¥3.5 MPa after 4 h when the ratio of latex polymer to rapid-set binder material was ¤0.33. The permeability resistance to chloride ions satisfied 2000 C after 7 days of curing for all ratios. The ratio of latex polymer to rapid-set binder material that satisfied all conditions for emergency pavement repair was ¤0.29.

  1. Highly permeable, cement-bounded backfilling mortars for SMA repositories

    International Nuclear Information System (INIS)

    Jacobs, F.; Mayer, G.; Wittmann, F.H.

    1994-03-01

    In low- and intermediate-level waste repositories, gas is produced due e.g. to corrosion. This gas must be able to escape from the repository in order to prevent damage to the repository structure. A cement-based backfill should take over this function. For this purpose, the composition of cement-based materials was varied to study their influence on porosity and permeability. In parallel to this study the behaviour of fresh concrete, the liberation of the heat of hydration and the hardened concrete properties were investigated. To characterize the permeability of cement-based materials the following parameters are important: 1) composition of the material (pore fabric), 2) storage conditions (degree of saturation), 3) degree of hydration (age), 4) measuring fluid. A change in the composition of cement-based materials can vary the permeability by ten orders of magnitude. It is shown that, by using dense aggregates, the transport of the fluid takes place through the matrix and along the aggregate/matrix interface. By using porous aggregates the permeability can be increased by two orders of magnitude. In the case of a dense matrix, porous aggregates do not alter the permeability. Increasing the matrix content or interface content increases permeability. Hence light weight mortars are an obvious choice. Like-grained mixes showed higher permeabilities in combination with better mechanical properties but, in comparison to normal mixes, they showed worse flow properties. With the composition cement-: water-: aggregate content 1:0.4:5.33 the likegrained mix with aggregates ranging from 2 to 3 mm proved to be a suitable material. With a low compaction after 28 days this mix reaches a permeability of 4.10 -12 m 2 and an uniaxial cylinder compressive strength of 16 N/mm 2 . (author) 58 figs., 23 tabs., refs

  2. Mechanism of /sup 67/Ga uptake by an experimental abscess. Permeability of plasma from blood vessel in abscess

    Energy Technology Data Exchange (ETDEWEB)

    Nitta, Kazuo; Ogawa, Hiroshi; Ando, Atsushi; Ando, Itsuko; Hiraki, Tatsunosuke; Hisada, Kinichi

    1985-06-01

    In the previous paper, we reported that /sup 67/Ga was accumulated in abscess and uptake rate of /sup 67/Ga in abscess increased with time after the injection of /sup 67/Ga-citrate. The present study was undertaken to elucidate the influence of blood flow on the accumulation of /sup 67/Ga in abscess. Five days after subcutaneous injection of 0.2 ml of turpentine to the rats, /sup 131/I-human serum albumin (HSA) was injected intravenously to the rats. At an appropriate time after the injection (10 min to 6 days), uptake rates of /sup 131/I-HSA in abscess and normal tissues were measured. Similarly, /sup 51/Cr-red blood cells (RBC) were injected intravenously to the above rats and the uptake rates of /sup 51/Cr-RBC were also measured. One, three, and 24 hours after injection of /sup 131/I-HSA, the uptake rates of /sup 131/I-HSA in abscess were 1.32 %dose/g, 1.84 %dose/g, and 0.82 %dose/g, respectively. However, the uptake rates of /sup 51/Cr-RBC in abscess was very small, and the value was 0.14 %dose/g at 24 hours after the injection. In the case of abscess, blood in the tissue fluid was very little, but the permeability of /sup 131/I-HSA from the blood vessel in the tissue was much larger than that of normal tissues. From these facts, it was deduced that the accelerated permeability caused the abscess accumulation of /sup 67/Ga.

  3. Effect of Organic Material on Mechanical, Hydrological, and Microstructural Properties of Mudstones

    Science.gov (United States)

    Altobelli, M. A.; Reece, J. S.

    2016-12-01

    In this research we analyze the influence of organic material on the mechanical and flow properties of mudstones. We uniformly mix peat, milled and harvested by Bord na Móna from the surface of bogs in Ireland, with natural mudstone from Site C0011 in the Nankai Trough, offshore Japan, obtained during Integrated Ocean Drilling Program Expedition 322. The mudstone had previously been disaggregated into a homogeneous dry powder of clay- and silt-sized particles. The peat is ground and dry-sieved to achieve a similar particle size distribution as the mudstone (mechanical and hydrological processes affected by peat, we prepare dry peat-mudstone mixtures with three different peat concentrations: 0 wt%, 5 wt%, and 10 wt%. Then, these peat - mudstone mixtures are saturated with deionized water at a water content of 109%, formed into stable slurries, and uniaxially compressed to an axial stress of 100 kPa using resedimentation, a method that simulates the natural behavior of deposition and burial in the laboratory under controlled conditions. How the organic material interacts with the mudstone matrix and pore fluid under compression influences the physical properties of the mudstones such as porosity, compressibility, and permeability; all of which are measured in the resedimentation experiments. We will also analyze the microstructural changes as a function of peat concentration using a petrographic microscope and scanning electron microscope. Due to the fibrous and absorbent nature of peat, we anticipate the peat to force tightly packed clay particles in the mudstone apart resulting in a looser microstructure and increased porosity, and thus, a higher compressibility and permeability. Understanding the controls on the mechanical and flow properties of hydrocarbon-bearing, fine-grained formations is crucial for exploration and successful production from hydrocarbon reservoirs. Additionally, this study has large implications for soil water storage and soil amendment to

  4. Laboratory Investigation on Physical and Mechanical Properties of Granite After Heating and Water-Cooling Treatment

    Science.gov (United States)

    Zhang, Fan; Zhao, Jianjian; Hu, Dawei; Skoczylas, Frederic; Shao, Jianfu

    2018-03-01

    High-temperature treatment may cause changes in physical and mechanical properties of rocks. Temperature changing rate (heating, cooling and both of them) plays an important role in those changes. Thermal conductivity tests, ultrasonic pulse velocity tests, gas permeability tests and triaxial compression tests are performed on granite samples after a heating and rapid cooling treatment in order to characterize the changes in physical and mechanical properties. Seven levels of temperature (from 25 to 900 °C) are used. It is found that the physical and mechanical properties of granite are significantly deteriorated by the thermal treatment. The porosity shows a significant increase from 1.19% at the initial state to 6.13% for samples heated to 900 °C. The increase in porosity is mainly due to three factors: (1) a large number of microcracks caused by the rapid cooling rate; (2) the mineral transformation of granite through high-temperature heating and water-cooling process; (3) the rapid cooling process causes the mineral particles to weaken. As the temperature of treatment increases, the thermal conductivity and P-wave velocity decrease while the gas permeability increases. Below 200 °C, the elastic modulus and cohesion increase with temperature increasing. Between 200 and 500 °C, the elastic modulus and cohesion have no obvious change with temperature. Beyond 500 °C, as the temperature increases, the elastic modulus and cohesion obviously decrease and the decreasing rate becomes slower with the increase in confining pressure. Poisson's ratio and internal frictional coefficient have no obvious change as the temperature increases. Moreover, there is a transition from a brittle to ductile behavior when the temperature becomes high. At 900 °C, the granite shows an obvious elastic-plastic behavior.

  5. Microstructure, mechanical properties, bio-corrosion properties and antibacterial properties of Ti–Ag sintered alloys

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Mian [Key Lab. for Anisotropy and Texture of Materials, Education Ministry of China, Northeastern University, Shenyang 110819 (China); Zhang, Erlin, E-mail: zhangel@atm.neu.edu.cn [Key Lab. for Anisotropy and Texture of Materials, Education Ministry of China, Northeastern University, Shenyang 110819 (China); Zhang, Lan [State Key Laboratory for Mechanical Behavior of Materials, Xi' an Jiaotong University, Xi' an 710049 (China)

    2016-05-01

    In this research, Ag element was selected as an antibacterial agent to develop an antibacterial Ti–Ag alloy by a powder metallurgy. The microstructure, phase constitution, mechanical properties, corrosion resistance and antibacterial properties of the Ti–Ag sintered alloys have been systematically studied by X-ray diffraction (XRD), scanning electron microscope (SEM), compressive test, electrochemical measurements and antibacterial test. The effects of the Ag powder size and the Ag content on the antibacterial property and mechanical property as well as the anticorrosion property have been investigated. The microstructure results have shown that Ti–Ag phase, residual pure Ag and Ti were the mainly phases in Ti–Ag(S75) sintered alloy while Ti{sub 2}Ag was synthesized in Ti–Ag(S10) sintered alloy. The mechanical test indicated that Ti–Ag sintered alloy showed a much higher hardness and the compressive yield strength than cp-Ti but the mechanical properties were slightly reduced with the increase of Ag content. Electrochemical results showed that Ag powder size had a significant effect on the corrosion resistance of Ti–Ag sintered alloy. Ag content increased the corrosion resistance in a dose dependent way under a homogeneous microstructure. Antibacterial tests have demonstrated that antibacterial Ti–Ag alloy was successfully prepared. It was also shown that the Ag powder particle size and the Ag content influenced the antibacterial activity seriously. The reduction in the Ag powder size was benefit to the improvement in the antibacterial property and the Ag content has to be at least 3 wt.% in order to obtain a strong and stable antibacterial activity against Staphylococcus aureus bacteria. The bacterial mechanism was thought to be related to the Ti{sub 2}Ag and its distribution. - Highlights: • Ti–Ag alloy with up to 99% antibacterial rate was developed by powder metallurgy. • The effects of the Ag powder size and the Ag content on the

  6. Mechanical Properties of Optimized Diamond Lattice Structure for Bone Scaffolds Fabricated via Selective Laser Melting

    Science.gov (United States)

    Zhang, David Z.; Zhang, Peng; Zhao, Miao; Jafar, Salman

    2018-01-01

    Developments in selective laser melting (SLM) have enabled the fabrication of periodic cellular lattice structures characterized by suitable properties matching the bone tissue well and by fluid permeability from interconnected structures. These multifunctional performances are significantly affected by cell topology and constitutive properties of applied materials. In this respect, a diamond unit cell was designed in particular volume fractions corresponding to the host bone tissue and optimized with a smooth surface at nodes leading to fewer stress concentrations. There were 33 porous titanium samples with different volume fractions, from 1.28 to 18.6%, manufactured using SLM. All of them were performed under compressive load to determine the deformation and failure mechanisms, accompanied by an in-situ approach using digital image correlation (DIC) to reveal stress–strain evolution. The results showed that lattice structures manufactured by SLM exhibited comparable properties to those of trabecular bone, avoiding the effects of stress-shielding and increasing longevity of implants. The curvature of optimized surface can play a role in regulating the relationship between density and mechanical properties. Owing to the release of stress concentration from optimized surface, the failure mechanism of porous titanium has been changed from the pattern of bottom-up collapse by layer (or cell row) to that of the diagonal (45°) shear band, resulting in the significant enhancement of the structural strength. PMID:29510492

  7. Physico-mechanical, morphological and biomedical properties of a novel natural wound dressing material.

    Science.gov (United States)

    Tavakoli, Javad

    2017-01-01

    Wound healing as a complex biological process greatly affects the quality of patients׳ lives. The high initial cost of wound treatment using advanced wound dressing is a major concern that warrants more attention. Because of the similarities between body macromolecules and polysaccharides and proteoglycans, gelatin and starch were used extensively as wound dressings; however their solubility in aqueous environment is known as a major drawback. Crosslinking, as a common method for enhancing mechanical properties, has its own limitation as some chemical cross-likers reduce biocompatibility. In this research, a simple and economical method for the fabrication of a novel wound dressing foam based on natural polymers of starch and gelatin with borax as the crosslinking agent is introduced. To evaluate the utility of the foams for wound dressing application, morphology, swelling behaviour and kinetics of swelling, vapour permeability, dimension stability, their mechanical properties and cytotoxicity as well as their ability to control release properties were examined as a function of crosslinking density. It was found that however, all borax-induced-samples show acceptable biocompatibility, incorporation of 30% borax solution optimises their mechanical properties. Copyright © 2016 Elsevier Ltd. All rights reserved.

  8. Mechanical Properties of Optimized Diamond Lattice Structure for Bone Scaffolds Fabricated via Selective Laser Melting.

    Science.gov (United States)

    Liu, Fei; Zhang, David Z; Zhang, Peng; Zhao, Miao; Jafar, Salman

    2018-03-03

    Developments in selective laser melting (SLM) have enabled the fabrication of periodic cellular lattice structures characterized by suitable properties matching the bone tissue well and by fluid permeability from interconnected structures. These multifunctional performances are significantly affected by cell topology and constitutive properties of applied materials. In this respect, a diamond unit cell was designed in particular volume fractions corresponding to the host bone tissue and optimized with a smooth surface at nodes leading to fewer stress concentrations. There were 33 porous titanium samples with different volume fractions, from 1.28 to 18.6%, manufactured using SLM. All of them were performed under compressive load to determine the deformation and failure mechanisms, accompanied by an in-situ approach using digital image correlation (DIC) to reveal stress-strain evolution. The results showed that lattice structures manufactured by SLM exhibited comparable properties to those of trabecular bone, avoiding the effects of stress-shielding and increasing longevity of implants. The curvature of optimized surface can play a role in regulating the relationship between density and mechanical properties. Owing to the release of stress concentration from optimized surface, the failure mechanism of porous titanium has been changed from the pattern of bottom-up collapse by layer (or cell row) to that of the diagonal (45°) shear band, resulting in the significant enhancement of the structural strength.

  9. The thermal and mechanical properties of a low-density glass-fiber-reinforced elastomeric ablation material

    Science.gov (United States)

    Engelke, W. T.; Robertson, R. W.; Bush, A. L.; Pears, C. D.

    1974-01-01

    An evaluation of the thermal and mechanical properties was performed on a molded low-density elastomeric ablation material designated as Material B. Both the virgin and charred states were examined to provide meaningful inputs to the design of a thermal protection system. Chars representative of the flight chars formed during ablation were prepared in a laboratory furnace from 600 K to 1700 K and properties of effective thermal conductivity, heat capacity, porosity and permeability were determined on the furnace chars formed at various temperature levels within the range. This provided a boxing of the data which will enable the prediction of the transient response of the material during flight ablation.

  10. Effect of the mechanical processing on the mechanical properties of MA956 alloy. II. Mechanical characterization

    International Nuclear Information System (INIS)

    Chao, J.; Gonzalez-Doncel, G.

    1998-01-01

    The mechanical properties at room and low temperature of MA 956 alloy in some stages of their processing route are evaluated. In this study the influence of crystallographic orientation on plastic deformation and brittle fracture, strongly anisotropic phenomena, is also considered. It is concluded that even though MA 956 alloy was designated for high temperature applications it could be also used for cryogenic temperatures applications. (Author) 8 refs

  11. Mechanical and Durability Properties of Fly Ash Based Concrete Exposed to Marine Environment

    Science.gov (United States)

    Kagadgar, Sarfaraz Ahmed; Saha, Suman; Rajasekaran, C.

    2017-06-01

    Efforts over the past few years for improving the performance of concrete suggest that cement replacement with mineral admixtures can enhance the strength and durability of concrete. Feasibility of producing good quality concrete by using alccofine and fly ash replacements is investigated and also the potential benefits from their incorporation were looked into. In this study, an attempt has been made to assess the performance of concrete in severe marine conditions exposed upto a period of 150 days. This work investigates the influence of alccofine and fly ash as partial replacement of cement in various percentages (Alccofine - 5% replacement to cement content) and (fly ash - 0%, 15%, 30%, 50% & 60% to total cementitious content) on mechanical and durability properties (Permit ion permeability test and corrosion current density) of concrete. Usage of alccofine and high quantity of fly ash as additional cementitious materials in concrete has resulted in higher workability of concrete. Inclusion of alccofine shows an early strength gaining property whereas fly ash results in gaining strength at later stage. Concrete mixes containing 5% alccofine with 15% fly ash replacement reported greater compressive strength than the other concrete mixes cured in both curing conditions. Durability test conducted at 56 and 150 days indicated that concrete containing higher percentages of fly ash resulted in lower permeability as well lesser corrosion density.

  12. Morphology, crystallization and dynamic mechanical properties of ...

    Indian Academy of Sciences (India)

    Unknown

    considerable interest both in industry and academia because of its significantly ... super-engineering materials because of their superior mecha- nical properties at ... proves the barrier (Kojima et al 1993c) and ablative. (Vaia et al 1999) ...

  13. Mechanical properties of brain tissue by indentation : interregional variation

    NARCIS (Netherlands)

    Dommelen, van J.A.W.; Sande, van der T.P.J.; Hrapko, M.; Peters, G.W.M.

    2010-01-01

    Although many studies on the mechanical properties of brain tissue exist, some controversy concerning the possible differences in mechanical properties of white and gray matter tissue remains. Indentation experiments are conducted on white and gray matter tissue of various regions of the cerebrum

  14. Microstructure and Mechanical Properties of a Laser Treated Al Alloy

    NARCIS (Netherlands)

    Noordhuis, J.; Hosson, J.Th.M. De

    An Al-Cu-Mg alloy, Al 2024-T3, was exposed to laser treatments at various scan velocities. In this paper the microstructural features and mechanical properties are reported. As far as the mechanical property is concerned a striking observation is a minimum in the hardness value at a laser scan

  15. Region-specific mechanical properties of the human patella tendon

    DEFF Research Database (Denmark)

    Haraldsson, B T; Aagaard, P; Krogsgaard, M

    2004-01-01

    The present study investigated the mechanical properties of tendon fascicles from the anterior and posterior human patellar tendon. Collagen fascicles from the anterior and posterior human patellar tendon in healthy young men (mean +/- SD, 29.0 +/- 4.6 yr, n = 6) were tested in a mechanical rig...... portion of the tendon, indicating region-specific material properties....

  16. Microstructure and mechanical properties of laser treated aluminium alloys

    NARCIS (Netherlands)

    deHosson, JTM; vanOtterloo, LDM; Noordhuis, J; Mazumder, J; Conde, O; Villar, R; Steen, W

    1996-01-01

    Al-Cu alloys and an Al-Cu-Mg alloy, Al 2024-T3, were exposed to laser treatments at various scan velocities. In this paper the microstructural features and mechanical properties are reported. As far as the mechanical property of the Al-Cu-Mg alloy is concerned a striking observation is a minimum in

  17. Mechanical properties of natural fibre reinforced polymer composites

    Indian Academy of Sciences (India)

    In the present communication, a study on the synthesis and mechanical properties of new series of green composites involving Hibiscus sabdariffa fibre as a reinforcing material in urea–formaldehyde (UF) resin based polymer matrix has been reported. Static mechanical properties of randomly oriented intimately mixed ...

  18. Characterization and modelling of the mechanical properties of mineral wool

    DEFF Research Database (Denmark)

    Chapelle, Lucie

    2016-01-01

    and as a consequence focus on the mechanical properties of mineral wool has intensified. Also understanding the deformation mechanisms during compression of low density mineral wool is crucial since better thickness recovery after compression will result in significant savings on transport costs. The mechanical...... properties of mineral wool relate closely to the arrangement and characteristics of the fibres inside the material. Because of the complex architecture of mineral wool, the characterization and the understanding of the mechanism of deformations require a new methodology. In this PhD thesis, a methodology...... of the structure on mechanical properties can be explored. The size of the representative volume elements for the prediction of the elastic properties is determined for two types of applied boundary conditions. For sufficiently large volumes, the predicted elastic properties are consistent with results from...

  19. Characterization of porosity in support of mechanical property analysis

    International Nuclear Information System (INIS)

    Price, R.H.; Martin, R.J. III; Boyd, P.J.

    1992-01-01

    Previous laboratory investigations of tuff have shown that porosity has a dominant, general effect on mechanical properties. As a result, it is very important for the interpretation of mechanical property data that porosity is measured on each sample tested. Porosity alone, however, does not address all of the issues important to mechanical behavior. Variability in size and distribution of pore space produces significantly different mechanical properties. A nondestructive technique for characterizing the internal structure of the sample prior to testing is being developed and the results are being analyzed. The information obtained from this technique can help in both qualitative and quantitative interpretation of test results

  20. An analytical model of the mechanical properties of bulk coal under confined stress

    Science.gov (United States)

    Wang, G.X.; Wang, Z.T.; Rudolph, V.; Massarotto, P.; Finley, R.J.

    2007-01-01

    This paper presents the development of an analytical model which can be used to relate the structural parameters of coal to its mechanical properties such as elastic modulus and Poisson's ratio under a confined stress condition. This model is developed primarily to support process modeling of coalbed methane (CBM) or CO2-enhanced CBM (ECBM) recovery from coal seam. It applied an innovative approach by which stresses acting on and strains occurring in coal are successively combined in rectangular coordinates, leading to the aggregated mechanical constants. These mechanical properties represent important information for improving CBM/ECBM simulations and incorporating within these considerations of directional permeability. The model, consisting of constitutive equations which implement a mechanically consistent stress-strains correlation, can be used as a generalized tool to study the mechanical and fluid behaviors of coal composites. An example using the model to predict the stress-strain correlation of coal under triaxial confined stress by accounting for the elastic and brittle (non-elastic) deformations is discussed. The result shows a good agreement between the prediction and the experimental measurement. ?? 2007 Elsevier Ltd. All rights reserved.

  1. Preparation, characterization and mechanical properties of k ...

    Indian Academy of Sciences (India)

    2017-06-09

    Jun 9, 2017 ... Nanocomposite; k-Carrageenan; SiO2 nanoparticles; mechanical strength; antimicrobial activity. 1. Introduction ... Silicon dioxide (SiO2)-filled polymer matrix com- posites have ... by using the agar disk diffusion method. 2.

  2. Phonon spectrum, mechanical and thermophysical properties of thorium carbide

    International Nuclear Information System (INIS)

    Pérez Daroca, D.; Jaroszewicz, S.; Llois, A.M.; Mosca, H.O.

    2013-01-01

    In this work, we study, by means of density functional perturbation theory and the pseudopotential method, mechanical and thermophysical properties of thorium carbide. These properties are derived from the lattice dynamics in the quasi-harmonic approximation. The phonon spectrum of ThC presented in this article, to the best authors’ knowledge, have not been studied, neither experimentally, nor theoretically. We compare mechanical properties, volume thermal expansion and molar specific capacities with previous results and find a very good agreement

  3. Phonon spectrum, mechanical and thermophysical properties of thorium carbide

    Energy Technology Data Exchange (ETDEWEB)

    Pérez Daroca, D., E-mail: pdaroca@tandar.cnea.gov.ar [Gerencia de Investigación y Aplicaciones, Comisión Nacional de Energía Atómica (Argentina); Consejo Nacional de Investigaciones Cientı´ficas y Técnicas (Argentina); Jaroszewicz, S. [Gerencia de Investigación y Aplicaciones, Comisión Nacional de Energía Atómica (Argentina); Instituto de Tecnología Jorge A. Sabato, UNSAM-CNEA (Argentina); Llois, A.M. [Gerencia de Investigación y Aplicaciones, Comisión Nacional de Energía Atómica (Argentina); Consejo Nacional de Investigaciones Cientı´ficas y Técnicas (Argentina); Mosca, H.O. [Gerencia de Investigación y Aplicaciones, Comisión Nacional de Energía Atómica (Argentina); Instituto de Tecnología Jorge A. Sabato, UNSAM-CNEA (Argentina)

    2013-06-15

    In this work, we study, by means of density functional perturbation theory and the pseudopotential method, mechanical and thermophysical properties of thorium carbide. These properties are derived from the lattice dynamics in the quasi-harmonic approximation. The phonon spectrum of ThC presented in this article, to the best authors’ knowledge, have not been studied, neither experimentally, nor theoretically. We compare mechanical properties, volume thermal expansion and molar specific capacities with previous results and find a very good agreement.

  4. Preparation and Mechanical Properties of Aligned Discontinuous Carbon Fiber Composites

    OpenAIRE

    DENG Hua; GAO Junpeng; BAO Jianwen

    2018-01-01

    Aligned discontinuous carbon fiber composites were fabricated from aligned discontinuous carbon fiber prepreg, which was prepared from continuous carbon fiber prepreg via mechanical high-frequency cutting. The internal quality and mechanical properties were characterized and compared with continuous carbon fiber composites. The results show that the internal quality of the aligned discontinuous carbon fiber composites is fine and the mechanical properties have high retention rate after the fi...

  5. Pectin- and gelatin-based film: effect of gamma irradiation on the mechanical properties and biodegradation

    Energy Technology Data Exchange (ETDEWEB)

    Jo, Cheorun; Kang, Hojin; Lee, Na Young; Kwon, Joong Ho; Byun, Myung Woo E-mail: mwbyun@kaeri.re.kr

    2005-04-01

    Agricultural by-products, pectin and gelatin, were used to prepare a biodegradable film. The film casting solution including the pectin and gelatin was irradiated at 0, 10, 20, and 30 kGy to investigate the irradiation effect on the mechanical properties of the film. The tensile strength of the 10 kGy-irradiated film was the highest among the treatments but the elongation at break, water vapour permeability, and swelling ratio were the lowest. Hunter color L*- and a*-values decreased but the b*-value increased as the irradiation dose increased. The total organic carbon content produced from the Paenibacillus polymyxa and Pseudomonas aeruginosa also showed that the film of 10 kGy-irradiated was lower than those of 0, 20, and 30 kGy-irradiated films. In conclusion, irradiation of the film casting solution at 10 kGy increased the mechanical properties of the pectin and gelatin based film. To manufacture the film by agricultural by-products, however, the irradiation dose of the film casting solution should be determined to achieve better mechanical properties.

  6. Biodegradability and mechanical properties of reinforced starch nanocomposites using cellulose nanofibers.

    Science.gov (United States)

    Babaee, Mehran; Jonoobi, Mehdi; Hamzeh, Yahya; Ashori, Alireza

    2015-11-05

    In this study the effects of chemical modification of cellulose nanofibers (CNFs) on the biodegradability and mechanical properties of reinforced thermoplastic starch (TPS) nanocomposites was evaluated. The CNFs were modified using acetic anhydride and the nanocomposites were fabricated by solution casting from corn starch with glycerol/water as the plasticizer and 10 wt% of either CNFs or acetylated CNFs (ACNFs). The morphology, water absorption (WA), water vapor permeability rate (WVP), tensile, dynamic mechanical analysis (DMA), and fungal degradation properties of the obtained nanocomposites were investigated. The results demonstrated that the addition of CNFs and ACNFs significantly enhanced the mechanical properties of the nanocomposites and reduced the WVP and WA of the TPS. The effects were more pronounced for the CNFs than the ACNFs. The DMA showed that the storage modulus was improved, especially for the CNFs/TPS nanocomposite. Compared with the neat TPS, the addition of nanofibers improved the degradation rate of the nanocomposite and particularly ACNFs reduced degradation rate of the nanocomposite toward fungal degradation. Copyright © 2015 Elsevier Ltd. All rights reserved.

  7. Estimation of mechanical properties of single wall carbon nanotubes ...

    Indian Academy of Sciences (India)

    Molecular mechanics; single wall carbon nanotube; mechanical proper- ... Fracture Mechanics); Rossi & Meo 2009). Furthermore, the work carried out by Natsuki & Endo. (2004), Xiao et al (2005) and Sun & Zhao (2005) in the direction of ..... Jin Y and Yuan F G 2003 Simulation of elastic properties of single walled carbon ...

  8. Hysteresis properties of the amorphous high permeability Co66Fe3Cr3Si15B13 alloy

    Directory of Open Access Journals (Sweden)

    V. S. Tsepelev

    2018-04-01

    Full Text Available The scaling law of minor loops was studied on an amorphous alloy Co66Fe3Cr3Si15B13 with a very high initial permeability (more than 150000 and low coercivity (about 0.1 A/m. An analytical expression for the coercive force in the Rayleigh region was derived. The coercive force is connected with the maximal magnetic field Hmax via the reversibility coefficient μi/ηHmax. Reversibility coefficient shows the relationship between reversible and irreversible magnetization processes. A universal dependence of magnetic losses for hysteresis Wh on the remanence Br with a power factor of 1.35 is confirmed for a wide range of magnetic fields strengths.

  9. Mechanical properties of additively manufactured thick honeycombs

    NARCIS (Netherlands)

    Hedayati, R.; Sadighi, M.; Mohammadi-Aghdam, M; Zadpoor, A.A.

    2016-01-01

    Honeycombs resemble the structure of a number of natural and biological materials such as cancellous bone, wood, and cork. Thick honeycomb could be also used for energy absorption applications. Moreover, studying the mechanical behavior of honeycombs under in-plane loading could help understanding

  10. Stochastic modelling in design of mechanical properties of nanometals

    International Nuclear Information System (INIS)

    Tengen, T.B.; Wejrzanowski, T.; Iwankiewicz, R.; Kurzydlowski, K.J.

    2010-01-01

    Polycrystalline nanometals are being fabricated through different processing routes and conditions. The consequence is that nanometals having the same mean grain size may have different grain size dispersion and, hence, may have different material properties. This has often led to conflicting reports from both theoretical and experimental findings about the evolutions of the mechanical properties of nanomaterials. The present paper employs stochastic model to study the impact of microstructure evolution during grain growth on the mechanical properties of polycrystalline nanometals. The stochastic model for grain growth and the stochastic model for changes in mechanical properties of nanomaterials are proposed. The model for the mechanical properties developed is tested on aluminium samples.Many salient features of the mechanical properties of the aluminium samples are revealed. The results show that the different mechanisms of grain growth impart different nature of response to the material mechanical properties. The conventional, homologous and anomalous temperature dependences of the yield stress have also been revealed to be due to different nature of interactions of the microstructures during evolution.

  11. Mechanical properties of F82H plates with different thicknesses

    Energy Technology Data Exchange (ETDEWEB)

    Sakasegawa, Hideo, E-mail: sakasegawa.hideo@jaea.go.jp; Tanigawa, Hiroyasu

    2016-11-01

    Highlights: • Mass effect, homogeneity, and anisotropy in mechanical properties were studied. • Thickness dependence of tensile property was not observed. • Thickness dependence of Charpy impact property was observed. • Appropriate mechanical properties were obtained using an electric furnace. - Abstract: Fusion DEMO reactor requires over 11,000 tons of reduced activation ferritic/martensitic steel and it is indispensable to develop the manufacturing technology for producing large-scale components of DEMO blanket with appropriate mechanical properties. This is because mechanical properties are generally degraded with increasing production volume. In this work, we focused mechanical properties of F82H–BA12 heat which was melted in a 20 tons electric arc furnace. Plates with difference thicknesses from 18 to 100 mm{sup t} were made from its ingot through forging and hot-rolling followed by heat treatments. Tensile and Charpy impact tests were then performed on plates focusing on their homogeneity and anisotropy. From the result, their homogeneity and anisotropy were not significant. No obvious differences were observed in tensile properties between the plates with different thicknesses. However, Charpy impact property changed with increasing plate thickness, i.e. the ductile brittle transition temperature of a 100 mm{sup t} thick plate was higher than that of the other thinner plates.

  12. Mechanical and barrier properties of maize starch-gelatin composite films: effects of amylose content.

    Science.gov (United States)

    Wang, Kun; Wang, Wenhang; Ye, Ran; Xiao, Jingdong; Liu, Yaowei; Ding, Junsheng; Zhang, Shaojing; Liu, Anjun

    2017-08-01

    In order to obtain new reinforcing bio-fillers to improve the physicochemical properties of gelatin-based films, three types of maize starch, waxy maize starch (Ap), normal starch (Ns) and high-amylose starch (Al), were incorporated into gelatin film and the resulting film properties were investigated, focusing on the impact of amylose content. The thickness, opacity and roughness of gelatin film increased depending on the amylose content along with the starch concentration. The effects of the three starches on the mechanical properties of gelatin film were governed by amylose content, starch concentration as well as environmental relative humidity (RH). At 75% RH, the presence of Al and Ns in the gelatin matrix increased the film strength but decreased its elongation, while Ap exhibited an inverse effect. Starch addition decreased the oxygen permeability of the film, with the lowest value at 20% Al and Ns. All starches, notably at 30% content, led to a decrease in the water vapor permeability of the film at 90% RH, especially Ns starch. Furthermore, the starches improved the thermal stability of the film to some extent. Fourier transform infrared spectra indicated that some weak intermolecular interactions such as hydrogen bonding occurred between gelatin and starch. Moreover, a high degree of B-type crystallinity of starch was characterized in Gel-Al film by X-ray diffraction. Tailoring the properties of gelatin film by the incorporation of different types of maize starch provides the potential to extend its applications in edible food packaging. © 2017 Society of Chemical Industry. © 2017 Society of Chemical Industry.

  13. Rationally designed synthetic protein hydrogels with predictable mechanical properties.

    Science.gov (United States)

    Wu, Junhua; Li, Pengfei; Dong, Chenling; Jiang, Heting; Bin Xue; Gao, Xiang; Qin, Meng; Wang, Wei; Bin Chen; Cao, Yi

    2018-02-12

    Designing synthetic protein hydrogels with tailored mechanical properties similar to naturally occurring tissues is an eternal pursuit in tissue engineering and stem cell and cancer research. However, it remains challenging to correlate the mechanical properties of protein hydrogels with the nanomechanics of individual building blocks. Here we use single-molecule force spectroscopy, protein engineering and theoretical modeling to prove that the mechanical properties of protein hydrogels are predictable based on the mechanical hierarchy of the cross-linkers and the load-bearing modules at the molecular level. These findings provide a framework for rationally designing protein hydrogels with independently tunable elasticity, extensibility, toughness and self-healing. Using this principle, we demonstrate the engineering of self-healable muscle-mimicking hydrogels that can significantly dissipate energy through protein unfolding. We expect that this principle can be generalized for the construction of protein hydrogels with customized mechanical properties for biomedical applications.

  14. Permeability of cork for water and ethanol.

    Science.gov (United States)

    Fonseca, Ana Luisa; Brazinha, Carla; Pereira, Helena; Crespo, Joao G; Teodoro, Orlando M N D

    2013-10-09

    Transport properties of natural (noncompressed) cork were evaluated for water and ethanol in both vapor and liquid phases. The permeability for these permeants has been measured, as well as the sorption and diffusion coefficients. This paper focuses on the differences between the transport of gases' relevant vapors and their liquids (water and ethanol) through cork. A transport mechanism of vapors and liquids is proposed. Experimental evidence shows that both vapors and liquids permeate not only through the small channels across the cells (plasmodesmata), as in the permeation of gases, but also through the walls of cork cells by sorption and diffusion as in dense membranes. The present study also shows that cork permeability for gases was irreversibly and drastically decreased after cork samples were exposed to ethanol or water in liquid phase.

  15. Mechanical properties of structural materials in HLM

    International Nuclear Information System (INIS)

    Moisa, A. E.; Valeca, S.; Pitigoi, V.

    2016-01-01

    The Generation IV nuclear systems are nowadays in the design stage, and this is one of the reasons of testing stage for candidate materials. The purpose of this paper is to present the tensile tests, for candidate materials. The studied test are: on temperature of 500°C in air, on mechanical testing machine Walter + Bie by using the furnace of the testing machine, and environmental molten lead using testing machine Instron, equipped with a lead testing device attached to it. Also the mechanical parameters will be determined on tensile strength and yield strength for steel 316L material to be used as candidate in achieving LFR reactor vessel type, and the microstructural analysis of surface breaking will be performed by electronic microscopy. The paper will present the main components, the operating procedure of the testing system, and the results of tensile tests in molten lead. (authors)

  16. Mechanical properties of ISABELLE superconducting coils

    International Nuclear Information System (INIS)

    Thompson, P.; Bertsche, A.; Fuhrmann, J.; Greene, A.; Grove, E.; Repeta, L.; Short, F.; Tannenbaum, M.; Wanderer, P.

    1981-01-01

    As a part of the manufacturing processes, several mechanical measurements are made on ISABELLE dipoles. These are done both to control the process and to provide information for the evaluation of the behavior of the completed magnets. This paper discusses the Young's Modulus (E = 1-3 x 10 6 psi), the thermal contraction of the coil assembly (ΔL/L = 290 +- 17 x 10 -5 at 77 0 K), and the loss of applied prestress with time

  17. Dependence of Glass Mechanical Properties on Thermal and Pressure History

    DEFF Research Database (Denmark)

    Smedskjær, Morten Mattrup; Bauchy, Mathieu

    Predicting the properties of new glasses prior to manufacturing is a topic attracting great industrial and scientific interest. Mechanical properties are currently of particular interest given the increasing demand for stronger, thinner, and more flexible glasses in recent years. However, as a non......-equilibrium material, the structure and properties of glass depend not only on its composition, but also on its thermal and pressure histories. Here we review our recent findings regarding the thermal and pressure history dependence of indentation-derived mechanical properties of oxide glasses....

  18. Mechanical property characterization of polymeric composites reinforced by continuous microfibers

    Science.gov (United States)

    Zubayar, Ali

    Innumerable experimental works have been conducted to study the effect of polymerization on the potential properties of the composites. Experimental techniques are employed to understand the effects of various fibers, their volume fractions and matrix properties in polymer composites. However, these experiments require fabrication of various composites which are time consuming and cost prohibitive. Advances in computational micromechanics allow us to study the various polymer based composites by using finite element simulations. The mechanical properties of continuous fiber composite strands are directional. In traditional continuous fiber laminated composites, all fibers lie in the same plane. This provides very desirable increases in the in-plane mechanical properties, but little in the transverse mechanical properties. The effect of different fiber/matrix combinations with various orientations is also available. Overall mechanical properties of different micro continuous fiber reinforced composites with orthogonal geometry are still unavailable in the contemporary research field. In this research, the mechanical properties of advanced polymeric composite reinforced by continuous micro fiber will be characterized based on analytical investigation and FE computational modeling. Initially, we have chosen IM7/PEEK, Carbon Fiber/Nylon 6, and Carbon Fiber/Epoxy as three different case study materials for analysis. To obtain the equivalent properties of the micro-hetero structures, a concept of micro-scale representative volume elements (RVEs) is introduced. Five types of micro scale RVEs (3 square and 2 hexagonal) containing a continuous micro fiber in the polymer matrix were designed. Uniaxial tensile, lateral expansion and transverse shear tests on each RVE were designed and conducted by the finite element computer modeling software ANSYS. The formulae based on elasticity theory were derived for extracting the equivalent mechanical properties (Young's moduli, shear

  19. Mechanical Properties of Austenitic Stainless Steel Made by Additive Manufacturing.

    Science.gov (United States)

    Luecke, William E; Slotwinski, John A

    2014-01-01

    Using uniaxial tensile and hardness testing, we evaluated the variability and anisotropy of the mechanical properties of an austenitic stainless steel, UNS S17400, manufactured by an additive process, selective laser melting. Like wrought materials, the mechanical properties depend on the orientation introduced by the processing. The recommended stress-relief heat treatment increases the tensile strength, reduces the yield strength, and decreases the extent of the discontinuous yielding. The mechanical properties, assessed by hardness, are very uniform across the build plate, but the stress-relief heat treatment introduced a small non-uniformity that had no correlation to position on the build plate. Analysis of the mechanical property behavior resulted in four conclusions. (1) The within-build and build-to-build tensile properties of the UNS S17400 stainless steel are less repeatable than mature engineering structural alloys, but similar to other structural alloys made by additive manufacturing. (2) The anisotropy of the mechanical properties of the UNS S17400 material of this study is larger than that of mature structural alloys, but is similar to other structural alloys made by additive manufacturing. (3) The tensile mechanical properties of the UNS S17400 material fabricated by selective laser melting are very different from those of wrought, heat-treated 17-4PH stainless steel. (4) The large discontinuous yielding strain in all tests resulted from the formation and propagation of Lüders bands.

  20. Mechanical properties of ISABELLE superconducting coils

    Energy Technology Data Exchange (ETDEWEB)

    Thompson, P.; Bertsche, A.; Fuhrmann, J.; Greene, A.; Grove, E.; Repeta, L.; Short, F.; Tannenbaum, M.; Wanderer, P.

    1981-01-01

    As a part of the manufacturing processes, several mechanical measurements are made on ISABELLE dipoles. These are done both to control the process and to provide information for the evaluation of the behavior of the completed magnets. This paper discusses the Young's Modulus (E = 1-3 x 10/sup 6/ psi), the thermal contraction of the coil assembly (..delta..L/L = 290 +- 17 x 10/sup -5/ at 77/sup 0/K), and the loss of applied prestress with time (approx. 20% for times 20 days).

  1. High temperature mechanical properties of iron aluminides

    International Nuclear Information System (INIS)

    Morris, D. G.; Munoz-Morris, M. A.

    2001-01-01

    Considerable attention has been given to the iron aluminide family of intermetallics over the past years since they offer considerable potential as engineering materials for intermediate to high temperature applications, particularly in cases where extreme oxidation or corrosion resistance is required. Despite efforts at alloy development, however, high temperature strength remains low and creep resistance poor. Reasons for the poor high-temperature strength of iron aluminides will be discussed, based on the ordered crystal structure, the dislocation structure found in the materials, and the mechanisms of dislocation pinning operating. Alternative ways of improving high temperature strength by microstructural modification and the inclusion of second phase particles will also be considered. (Author)

  2. Estimating soil hydraulic properties from soil moisture time series by inversion of a dual-permeability model

    Science.gov (United States)

    Dalla Valle, Nicolas; Wutzler, Thomas; Meyer, Stefanie; Potthast, Karin; Michalzik, Beate

    2017-04-01

    Dual-permeability type models are widely used to simulate water fluxes and solute transport in structured soils. These models contain two spatially overlapping flow domains with different parameterizations or even entirely different conceptual descriptions of flow processes. They are usually able to capture preferential flow phenomena, but a large set of parameters is needed, which are very laborious to obtain or cannot be measured at all. Therefore, model inversions are often used to derive the necessary parameters. Although these require sufficient input data themselves, they can use measurements of state variables instead, which are often easier to obtain and can be monitored by automated measurement systems. In this work we show a method to estimate soil hydraulic parameters from high frequency soil moisture time series data gathered at two different measurement depths by inversion of a simple one dimensional dual-permeability model. The model uses an advection equation based on the kinematic wave theory to describe the flow in the fracture domain and a Richards equation for the flow in the matrix domain. The soil moisture time series data were measured in mesocosms during sprinkling experiments. The inversion consists of three consecutive steps: First, the parameters of the water retention function were assessed using vertical soil moisture profiles in hydraulic equilibrium. This was done using two different exponential retention functions and the Campbell function. Second, the soil sorptivity and diffusivity functions were estimated from Boltzmann-transformed soil moisture data, which allowed the calculation of the hydraulic conductivity function. Third, the parameters governing flow in the fracture domain were determined using the whole soil moisture time series. The resulting retention functions were within the range of values predicted by pedotransfer functions apart from very dry conditions, where all retention functions predicted lower matrix potentials

  3. Pentiptycene-based polyurethane with enhanced mechanical properties and CO2-plasticization resistance for thin film gas separation membranes.

    Science.gov (United States)

    Pournaghshband Isfahani, Ali; Sadeghi, Morteza; Wakimoto, Kazuki; Shrestha, Binod Babu; Bagheri, Rouhollah; Sivaniah, Easan; Ghalei, Behnam

    2018-04-30

    Development of thin film composite (TFC) membranes offers an opportunity to achieve the permeability/selectivity requirements for optimum CO2 separation performance. However, the durability and performance of thin film gas separation membranes are mostly challenged by weak mechanical properties and high CO2 plasticization. Here, we designed new polyurethane (PU) structures with bulky aromatic chain extenders that afford preferred mechanical properties for ultra-thin film formation. An improvement of about 1500% in Young's modulus and 600% in hardness was observed for pentiptycene-based PUs compared to typical PU membranes. Single (CO2, H2, CH4, and N2) and mixed (CO2/N2 and CO2/CH4) gas permeability tests were performed on the PU membranes. The resulting TFC membranes showed a high CO2 permeance up to 1400 GPU (10-6 cm3(STP) cm-2s-1 cmHg-1) and the CO2/N2 and CO2/H2 selectivities of about 22 and 2.1, respectively. The enhanced mechanical properties of pentiptycene-based PUs results in high performance thin membranes with the similar selectivity of the bulk polymer. The thin film membranes prepared from pentiptycene-based PUs also showed a two-fold enhanced plasticization resistance compared to non-pentiptycene containing PU membranes.

  4. Physicochemical, mechanical and thermal properties of chitosan films with and without sorbitol.

    Science.gov (United States)

    Liu, Mei; Zhou, Yibin; Zhang, Yang; Yu, Chen; Cao, Shengnan

    2014-09-01

    The effect of sorbitol on the physicochemical, mechanical and thermal properties of chitosan films with different degrees of deacetylation (DD; i.e., DD85% and DD95%) was investigated. The thickness, moisture content (MC), water solubility (WS) and water-vapor permeability (WVP) of the films were evaluated. Sorbitol addition reduced MC, increased WS and significantly (psorbitol increased the strain and decreased stress for both DD films, but DD95% could sustain higher strain and DD85% could sustain higher stress. Thermogravimetrics analysis and differential scanning calorimetry showed that sorbitol elicited a lower degradation temperature for both films, and that DD95% films exhibited higher thermal stability than DD85% films. Copyright © 2014 Elsevier B.V. All rights reserved.

  5. Effect of hydrogen on the microstructure, mechanical properties and phase transformations in austenitic steels

    International Nuclear Information System (INIS)

    Li, Y.Y.; Xing, Z.S.

    1989-01-01

    Effect of high-pressure hydrogen charging on the microstructure, mechanical properties and phase transformations in austenitic steels has been investigated and discussed. The results show that the strength and impact toughness of the steels increase slightly and that the ductility decreases after hydrogen charging. The existence of δ-ferrite deteriorates the resistance to hydrogen embrittlement (HE) of the steels. The occurrence of carbide in the steel resulted from aging reduces the ductility of the steel and makes the steel sensitive to HE. The existence of sufficient hydrogen promotes the ε-martensitic transformation and suppresses the α'-martensitic transformation. The permeabilities and diffusivities of hydrogen in the steels have also been determined. (orig.)

  6. Mechanical, barrier and morphological properties of starch nanocrystals-reinforced pea starch films.

    Science.gov (United States)

    Li, Xiaojing; Qiu, Chao; Ji, Na; Sun, Cuixia; Xiong, Liu; Sun, Qingjie

    2015-05-05

    To characterize the pea starch films reinforced with waxy maize starch nanocrystals, the mechanical, water vapor barrier and morphological properties of the composite films were investigated. The addition of starch nanocrystals increased the tensile strength of the composite films, and the value of tensile strength of the composite films was highest when starch nanocrystals content was 5% (w/w). The moisture content (%), water vapor permeability, and water-vapor transmission rate of the composite films significantly decreased as starch nanocrystals content increased. When their starch nanocrystals content was 1-5%, the starch nanocrystals dispersed homogeneously in the composite films, resulting in a relatively smooth and compact film surface and better thermal stability. However, when starch nanocrystals content was more than 7%, the starch nanocrystals began to aggregate, which resulted in the surface of the composite films developing a longitudinal fibrous structure. Copyright © 2014 Elsevier Ltd. All rights reserved.

  7. The Effects of SiO2 Nanoparticles on Mechanical and Physicochemical Properties of Potato Starch Films

    Directory of Open Access Journals (Sweden)

    Z. Torabi

    2013-06-01

    Full Text Available In this paper effect of SiO2 nanoparticles was investigated on potato starch films. Potato starch films were prepared by casting method with addition of nano-silicon dioxide and a mixture of sorbitol/glycerol (weight ratio of 3 to 1 as plasticizers. SiO2 nanoparticles incorporated to the potato starch films at different concentrations 0, 1, 2, 3, and 5% of total solid, and the films were dried under controlled conditions.  Physicochemical properties such as water absorption capacity (WAC, water vapor permeability (WVP and mechanical properties of the films were measured. Results show that by increasing the concentration of silicon dioxide nanoparticles, mechanical properties of films can be improved. Also incorporation of silicon dioxide nanoparticles in the structure of biopolymer decrease permeability of the gaseous molecules such as water vapor. In summary, addition of silicon dioxide nanoparticles improves functional properties of potato starch films and these bio Nano composites can be used in food packaging.

  8. A multi-scale approach of mechanical and transport properties of cementitious materials under rises of temperature

    International Nuclear Information System (INIS)

    Caratini, G.

    2012-01-01

    The modern industrial activities (storage of nuclear waste, geothermal wells, nuclear power plants,...) can submit cementitious materials to some extreme conditions, for example at temperatures above 200 C. This level of temperature will induce phenomena of dehydration in the cement paste, particularly impacting the CSH hydrates which led to the mechanical cohesion. The effects of these temperatures on the mechanical and transport properties have been the subject of this thesis.To understand these effects, we need to take into account the heterogeneous, porous, multi-scale aspects of these materials. To do this, micro-mechanics and homogenization tools based on the Eshelby problem's solution were used. Moreover, to support this multi-scale modeling, mechanical testing based on the theory of porous media were conducted. The measurements of modulus compressibility, permeability and porosity under confining pressure were used to investigate the mechanisms of degradation of these materials during thermal loads up to 400 C. (author)

  9. Mechanical Properties of Plug Welds after Micro-Jet Cooling

    Directory of Open Access Journals (Sweden)

    Hadryś D.

    2016-12-01

    Full Text Available New technology of micro-jet welding could be regarded as a new way to improve mechanical properties of plug welds. The main purpose of that paper was analyzing of mechanical properties of plug welds made by MIG welding method with micro-jet cooling. The main way for it was comparison of plug welds made by MIG welding method with micro-jet cooling and plug welds made by ordinary MIG welding method. It is interesting for steel because higher amount of acicular ferrite (AF in weld metal deposit (WMD is obtained in MIG welding method with micro-jet cooling in relation to ordinary MIG welding method. This article presents the influence of the cooling medium and the number of micro-jet streams on mechanical properties of the welded joint. Mechanical properties were described by force which is necessary to destroy weld joint.

  10. Mechanical properties of short doughs and their corresponding biscuits

    NARCIS (Netherlands)

    Baltsavias, A.

    1996-01-01


    The mechanical properties of short doughs of various composition were determined in small amplitude oscillatory experiments and in uniaxial compression. Regardless of composition, the linear region was very limited; beyond that, pronounced yielding and flow occurred. Conductimetry was

  11. Densely crosslinked polycarbosiloxanes .2. Thermal and mechanical properties

    NARCIS (Netherlands)

    Flipsen, T.A C; Derks, R.; van der Vegt, H.A.; Stenekes, R.; Pennings, A.J; Hadziioannou, G

    1997-01-01

    The thermal and mechanical properties of two densely crosslinked polycarbosiloxane systems were investigated in relation to the molecular structure. The networks were prepared from functional branched prepolymers and crosslinked via a hydrosilylation curing reaction. The prepolymers having only

  12. Thermal, electrical, mechanical and fluidity properties of polyester ...

    Indian Academy of Sciences (India)

    Bariş Şimşek

    2018-04-13

    Apr 13, 2018 ... of POREC simultaneously is necessary for real-world applications. ... analysis approach containing a design of experiment (DoE) methodology ...... C–S–H gel and mechanical properties: case of ternary Port- land cements ...

  13. effects of sulphur addition on addition on and mechanical properties

    African Journals Online (AJOL)

    User

    234-8034714355. 8034714355. 1. EFFECTS OF SULPHUR ADDITION ON. ADDITION ON. 2. AND MECHANICAL PROPERTIES O. 3. 4. C. W. Onyia. 5. 1DEPT. OF METALLURGICAL AND MATERIALS. 6. 2, 4DEPT. OF METALLURGICAL ...

  14. Using Quantum Mechanics to Predict Shock Properties of Explosives

    National Research Council Canada - National Science Library

    Romero, N. A; Mattson, W. D; Rice, B. M

    2006-01-01

    .... As little as ten years ago, quantum mechanical calculations were restricted to predictions of static properties of systems containing tens of atoms, thus limiting first principles explorations to gas...

  15. Properties, Mechanisms and Predictability of Eddies in the Red Sea

    KAUST Repository

    Zhan, Peng

    2018-01-01

    of Red Sea eddies, including their temporal and spatial properties, their energy budget, the mechanisms of their evolution, and their predictability. Remote sensing data, in-situ observations, the oceanic general circulation model, and data assimilation

  16. Evaluation on mechanical properties of woven aloevera and sisal ...

    Indian Academy of Sciences (India)

    Administrator

    behaviour of this composite is observed to be more effec- tive.5 The fibre .... been made to study the mechanical properties of woven aloevera and ... In each case, minimum of ... tions in automotive components, structures and consumer goods.

  17. Effect of Mechanical Alloying Atmospheres and Oxygen Concentration on Mechanical Properties of ODS Ferritic Steels

    International Nuclear Information System (INIS)

    Noh, Sanghoon; Choi, Byoungkwon; Han, Changhee; Kim, Kibaik; Kang, Sukhoon; Chun, Youngbum; Kim, Taekyu

    2013-01-01

    Finely dispersed nano-oxide particles with a high number density in the homogeneous grain matrix are essential to achieve superior mechanical properties at high temperatures, and these unique microstructures can be obtained through the mechanical alloying (MA) and hot consolidation process. The microstructure and mechanical property of ODS steel significantly depends on its powder property and the purity after the MA process. These contents should be carefully controlled to improve the mechanical property at elevated temperature. In particular, appropriate the control of oxygen concentration improves the mechanical property of ODS steel at high temperature. An effective method is to control the mechanical alloying atmosphere by high purity inert gas. In the present study, the effects of mechanical alloying atmospheres and oxygen concentration on the mechanical property of ODS steel were investigated. ODS ferritic alloys were fabricated in various atmospheres, and the HIP process was used to investigate the effects of MA atmospheres and oxygen concentration on the microstructure and mechanical property. ODS ferritic alloys milled in an Ar-H 2 mixture, and He is effective to reduce the excess oxygen concentration. The YH 2 addition made an extremely reduced oxygen concentration by the internal oxygen reduction reaction and resulted in a homogeneous microstructure and superior creep strength

  18. Mechanical properties of aluminium honeycomb impact limiters

    International Nuclear Information System (INIS)

    Maji, A.K.; Satpathi, D.; Donald, S.

    1992-01-01

    Aluminium honeycombs have been extensively used as impact limiters in nuclear waste transport casks. The mechanical behaviour of these shock absorbing materials was studied to develop an extensive experimental database. A series of tests were performed along various loading paths. Different densities of aluminium honeycombs were tested in different orientations. Static tests included uniaxial tension, uniaxial compression and torsion. Dynamic tests were conducted at different strain rates of up to 100 s -1 , to generate experimental data relevant to accident situations. Dynamic studies included the effects of specimen size and confinement. The purpose of using different loading paths was to generate an extensive experimental database which may also be used to develop constitutive models for these materials. Design charts were constructed which can be accessed by various cask designers to optimise and economise on cask development. (Author)

  19. Measuring the mechanical properties of molecular conformers

    Science.gov (United States)

    Jarvis, S. P.; Taylor, S.; Baran, J. D.; Champness, N. R.; Larsson, J. A.; Moriarty, P.

    2015-09-01

    Scanning probe-actuated single molecule manipulation has proven to be an exceptionally powerful tool for the systematic atomic-scale interrogation of molecular adsorbates. To date, however, the extent to which molecular conformation affects the force required to push or pull a single molecule has not been explored. Here we probe the mechanochemical response of two tetra(4-bromophenyl)porphyrin conformers using non-contact atomic force microscopy where we find a large difference between the lateral forces required for manipulation. Remarkably, despite sharing very similar adsorption characteristics, variations in the potential energy surface are capable of prohibiting probe-induced positioning of one conformer, while simultaneously permitting manipulation of the alternative conformational form. Our results are interpreted in the context of dispersion-corrected density functional theory calculations which reveal significant differences in the diffusion barriers for each conformer. These results demonstrate that conformational variation significantly modifies the mechanical response of even simple porpyhrins, potentially affecting many other flexible molecules.

  20. Determination of mechanical and hydraulic properties of PVA hydrogels.

    Science.gov (United States)

    Kazimierska-Drobny, Katarzyna; El Fray, Miroslawa; Kaczmarek, Mariusz

    2015-03-01

    In this paper the identification of mechanical and hydraulic parameters of poly(vinyl alcohol) (PVA) hydrogels is described. The identification method follows the solution of inverse problem using experimental data from the unconfined compression test and the poroelastic creep model. The sensitivity analysis of the model shows significant dependence of the creep curves on investigated parameters. The hydrogels containing 22% PVA and 25% PVA were tested giving: the drained Youngs modulus of 0.71 and 0.9MPa; the drained Poisson's ratio of 0.18 and 0.31; and the permeability of 3.64·10(-15) and 3.29·10(15)m(4)/Ns, respectively. The values of undrained Youngs modulus were determined by measuring short period deformation of samples in the unconfined tests. A discussion on obtained results is presented. Copyright © 2014 Elsevier B.V. All rights reserved.

  1. Mechanical properties along interfaces of bonded structures in fusion reactors

    International Nuclear Information System (INIS)

    Hassan, M.H.; Kulcinski, G.L.

    1993-01-01

    Proper assessment of the mechanical properties along interfaces of bonded structures currently used in many fusion reactor designs is essential to compare the different fabrication techniques. A Mechanical Properties Microprobe (MPM) was used to measure hardness and Young's modules along the interfaces of Be/Cu bonded structure. The MPM was able to distinguish different fabrication techniques by a direct measurement of the hardness, Young's modules, and H/E 2 which reflects the ability of deformation of the interfacial region

  2. Mechanical properties of soldered joints of niobium base alloys

    International Nuclear Information System (INIS)

    Grishin, V.L.

    1980-01-01

    Mechanical properties of soldered joints of niobium alloys widely distributed in industry: VN3, VN4, VN5A, VN5AE, VN5AEP etc., 0.6-1.2 mm thick are investigated. It is found out that the usage of zirconium-vanadium, titanium-tantalum solders for welding niobium base alloys permits to obtain soldered joints with satisfactory mechanical properties at elevated temperatures

  3. To Study Capping or Lamination Tendency of Tablets Through Evaluation of Powder Rheological Properties and Tablet Mechanical Properties of Directly Compressible Blends.

    Science.gov (United States)

    Dudhat, Siddhi M; Kettler, Charles N; Dave, Rutesh H

    2017-05-01

    Air entrapment efficiency of the powders is one of the main factors leading to occurrence of capping or lamination tendency of tablets manufactured from the directly compressible powder blends. The purpose of the current research was to study this underlying cause leading to occurrence of capping or lamination of tablets through evaluation of powder rheological properties. Powder blends were prepared by addition of 0% w/w to 100% w/w of individual active pharmaceutical ingredient (API) [two model API: acetaminophen (APAP) and ibuprofen (IBU)] with microcrystalline cellulose without and with 0.5% w/w Magnesium Stearate as lubricant. Powder rheological properties were analyzed using FT4 Powder Rheometer for dynamic, bulk, and shear properties. Tablet mechanical properties of the respective blends were studied by determining the ability of the material to form tablet of specific strength under applied compaction pressure through tabletability profile. The results showed that powder rheometer distinguished the powder blends based on their ability to relieve entrapped air along with the distinctive flow characteristics. Powder blend prepared with increasing addition of APAP displayed low powder permeability as compared to IBU blends with better powder permeability, compressibility and flow characteristics. Also, lubrication of the APAP blends did not ease their ability to relieve air. Tabletability profiles revealed the potential occurrence of capping or lamination in tablets prepared from the powder blends with high APAP content. This study can help scientist to understand tableting performance at the early-developmental stages and can avoid occurrence capping and lamination of tablets.

  4. Physical and mechanical properties of biobased materials - Starch polylactate and polyhydroxybutyrate

    DEFF Research Database (Denmark)

    Bergenholtz, Karina P.; Nielsen, Per Væggemose; Olsen, M.B.

    2001-01-01

    Commercial and semi-commercial biobased materials (Polylactate, PLA, polyhydroxybutyrate, PHB, wheat starch and corn starch) were investigated. Physical and mechanical characterisation (tensile strength, elongation, tear strength, compression, gas permeability (CO2 and O-2) and water vapour...... permeability (WVP)) was examined. Tests on both films and cups show potential use of these materials for primary food packaging, especially PLA and PHB. An interesting O-2:CO2 permeability ratio (1:7 to 1:12) was seen, which make these materials suitable for packaging of food with high respiration...

  5. A lattice Boltzmann investigation of steady-state fluid distribution, capillary pressure and relative permeability of a porous medium: Effects of fluid and geometrical properties

    Science.gov (United States)

    Li, Zi; Galindo-Torres, Sergio; Yan, Guanxi; Scheuermann, Alexander; Li, Ling

    2018-06-01

    Simulations of simultaneous steady-state two-phase flow in the capillary force-dominated regime were conducted using the state-of-the-art Shan-Chen multi-component lattice Boltzmann model (SCMC-LBM) based on two-dimensional porous media. We focused on analyzing the fluid distribution (i.e., WP fluid-solid, NP fluid-solid and fluid-fluid interfacial areas) as well as the capillary pressure versus saturation curve which was affected by fluid and geometrical properties (i.e., wettability, adhesive strength, pore size distribution and specific surface area). How these properties influenced the relative permeability versus saturation relation through apparent effective permeability and threshold pressure gradient was also explored. The SCMC-LBM simulations showed that, a thin WP fluid film formed around the solid surface due to the adhesive fluid-solid interaction, resulting in discrete WP fluid distributions and reduction of the WP fluid mobility. Also, the adhesive interaction provided another source of capillary pressure in addition to capillary force, which, however, did not affect the mobility of the NP fluid. The film fluid effect could be enhanced by large adhesive strength and fine pores in heterogeneous porous media. In the steady-state infiltration, not only the NP fluid but also the WP fluid were subjected to the capillary resistance. The capillary pressure effect could be alleviated by decreased wettability, large average pore radius and improved fluid connectivity in heterogeneous porous media. The present work based on the SCMC-LBM investigations elucidated the role of film fluid as well as capillary pressure in the two-phase flow system. The findings have implications for ways to improve the macroscopic flow equation based on balance of force for the steady-state infiltration.

  6. Structure–mechanics property relationship of waste derived biochars

    International Nuclear Information System (INIS)

    Das, Oisik; Sarmah, Ajit K.; Bhattacharyya, Debes

    2015-01-01

    The widespread applications of biochar in agriculture and environmental remediation made the scientific community ignore its mechanical properties. Hence, to examine the scope of biochar's structural applications, its mechanical properties have been investigated in this paper through nanoindentation technique. Seven waste derived biochars, made under different pyrolysis conditions and from diverse feedstocks, were studied via nanoindentation, infrared spectroscopy, X–ray crystallography, thermogravimetry, and electron microscopy. Following this, an attempt was made to correlate the biochars' hardness/modulus with reaction conditions and their chemical properties. The pine wood biochar made at 900 °C and 60 min residence time was found to have the highest hardness and elastic modulus of 4.29 and 25.01 GPa, respectively. It was shown that a combination of higher heat treatment (≥ 500 °C) temperature and longer residence time (~ 60 min) increases the values of hardness and modulus. It was further realized that pyrolysis temperature was a more dominant factor than residence time in determining the final mechanical properties of biochar particles. The degree of aromaticity and crystallinity of the biochar were also correlated with higher values of hardness and modulus. - Highlights: • Characterization was done on waste based biochars which included nanoindentation. • Pine saw dust biochar made at 900 °C for 60 min had highest hardness/modulus. • Combination of temperature/residence time affect biochar's mechanical propertie.s • Aromaticity and crystallinity positively affected biochar's mechanical properties.

  7. Prediction of mechanical properties for hexagonal boron nitride nanosheets using molecular mechanics model

    Energy Technology Data Exchange (ETDEWEB)

    Natsuki, Toshiaki [Shinshu University, Faculty of Textile Science and Technology, Ueda (Japan); Shinshu University, Institute of Carbon Science and Technology, Nagano (Japan); Natsuki, Jun [Shinshu University, Institute of Carbon Science and Technology, Nagano (Japan)

    2017-04-15

    Mechanical behaviors of nanomaterials are not easy to be evaluated in the laboratory because of their extremely small size and difficulty controlling. Thus, a suitable model for the estimation of the mechanical properties for nanomaterials becomes very important. In this study, the elastic properties of boron nitride (BN) nanosheets, including the elastic modulus, the shear modulus, and the Poisson's ratio, are predicted using a molecular mechanics model. The molecular mechanics force filed is established to directly incorporate the Morse potential function into the constitutive model of nanostructures. According to the molecular mechanics model, the chirality effect of hexagonal BN nanosheets on the elastic modulus is investigated through a closed-form solution. The simulated result shows that BN nanosheets exhibit an isotropic elastic property. The present analysis yields a set of very simple formulas and is able to be served as a good approximation on the mechanical properties for the BN nanosheets. (orig.)

  8. Prediction of mechanical properties for hexagonal boron nitride nanosheets using molecular mechanics model

    International Nuclear Information System (INIS)

    Natsuki, Toshiaki; Natsuki, Jun

    2017-01-01

    Mechanical behaviors of nanomaterials are not easy to be evaluated in the laboratory because of their extremely small size and difficulty controlling. Thus, a suitable model for the estimation of the mechanical properties for nanomaterials becomes very important. In this study, the elastic properties of boron nitride (BN) nanosheets, including the elastic modulus, the shear modulus, and the Poisson's ratio, are predicted using a molecular mechanics model. The molecular mechanics force filed is established to directly incorporate the Morse potential function into the constitutive model of nanostructures. According to the molecular mechanics model, the chirality effect of hexagonal BN nanosheets on the elastic modulus is investigated through a closed-form solution. The simulated result shows that BN nanosheets exhibit an isotropic elastic property. The present analysis yields a set of very simple formulas and is able to be served as a good approximation on the mechanical properties for the BN nanosheets. (orig.)

  9. The Determination of Some Mechanical Properties of Scheffe's ...

    African Journals Online (AJOL)

    The work determined some mechanical properties of fresh and matured concrete. These properties include Slump, Compressive Strength, Static modulus of elasticity and Modulus of rigidity. It applied Scheffe's optimization theory to determine the ratio of the combined constituents of the concrete mix. The results showed that ...

  10. Grewia Gum 1: Some Mechanical and Swelling Properties of ...

    African Journals Online (AJOL)

    Purpose: To study the mechanical and dynamic swelling properties of grewia gum, evaluate its compression behaviour and determine the effect of drying methods on its properties. Methods: Compacts (500 mg) of both freeze-dried and air-dried grewia gum were separately prepared by compression on a potassium bromide ...

  11. Data for prediction of mechanical properties of aspen flakeboards

    Science.gov (United States)

    C. G. Carll; P. Wang

    1983-01-01

    This research compared two methods of producing flakeboards with uniform density distribution (which could then be used to predict bending properties of flakeboards with density gradients). One of the methods was suspected of producing weak boards because it involved exertion of high pressures on cold mats. Although differences were found in mechanical properties of...

  12. Determination of Some Mechanical Properties of Almond Seed ...

    African Journals Online (AJOL)

    Akorede

    I. INTRODUCTION. Information on mechanical properties of agricultural products as a function of moisture content is needed in the design and adjustment of machines used during harvest, separation, cleaning, handling and storage. It is also used in processing these agricultural materials into food. The properties useful for ...

  13. Effects of moisture on the mechanical properties of glass fibre ...

    Indian Academy of Sciences (India)

    However, the properties were relatively inferior when treated with boiling water for longer hours attributing to ingress of moisture by capillary action through the interface between the fibre and the resin matrix. Considering the rates of moisture absorption and correlating with the mechanical properties, it was observed that the ...

  14. Mechanical and physical properties of agro-based fiberboard

    Science.gov (United States)

    S. Lee; T.F. Shupe; C.Y. Hse

    2006-01-01

    In order to better utilize agricultural fibers as an alternative resource for composite panels, several variables were investigated to improve mechanical and physical properties of agm-based fiberboard. This study focused on the effect of fiber morphology, slenderness ratios (UD), and fiber mixing combinations on panel properties. The panel construction types were also...

  15. Effects of Polyethylene Glycol on the Mechanical Properties of ...

    African Journals Online (AJOL)

    Akorede

    investigate the mechanical properties and microstructural evaluation of steel. The test ... quenchant on the properties of steel (Eshraghi-Kakhki et al, ... Alloy Steel ... Table 1: Chemical composition of the steel used in this experiment. Elements. C. Si. S ... Cu. W. As. Composition 0.0555 0.00180 0.0029 0.3031 0.0003 0.0060.

  16. Surface modification, microstructure and mechanical properties of investment cast superalloy

    OpenAIRE

    M. Zielińska; K. Kubiak; J. Sieniawski

    2009-01-01

    Purpose: The aim of this work is to determine physical and chemical properties of cobalt aluminate (CoAl2O4) modifiers produced by different companies and the influence of different types of modifiers on the grain size, the microstructure and mechanical properties of high temperature creep resisting superalloy René 77.Design/methodology/approach: The first stage of the research work took over the investigations of physical and chemical properties of cobalt aluminate manufactured by three diff...

  17. Mechanical properties of lanthanum and yttrium chromites

    Energy Technology Data Exchange (ETDEWEB)

    Paulik, S.W.; Armstrong, T.R. [Pacific Northwest National Lab., Richland, WA (United States)

    1996-12-31

    In an operating high-temperature (1000{degrees}C) solid oxide fuel cell (SOFC), the interconnect separates the fuel (P(O{sub 2}){approx}10{sup -16} atm) and the oxidant (P(O2){approx}10{sup 0.2} atm), while being electrically conductive and connecting the cells in series. Such severe atmospheric and thermal demands greatly reduce the number of viable candidate materials. Only two materials, acceptor substituted lanthanum chromite and yttrium chromite, meet these severe requirements. In acceptor substituted chromites (Sr{sup 2+} or Ca{sup 2+} for La{sup 3+}), charge compensation is primarily electronic in oxidizing conditions (through the formation of Cr{sup 4+}). Under reducing conditions, ionic charge compensation becomes significant as the lattice becomes oxygen deficient. The formation of oxygen vacancies is accompanied by the reduction of Cr{sup 4+} ions to Cr{sup 3+} and a resultant lattice expansion. The lattice expansion observed in large chemical potential gradients is not desirable and has been found to result in greatly reduced mechanical strength.

  18. Microstructures and mechanical properties of an Osprey aluminium 7000 alloy

    International Nuclear Information System (INIS)

    Cottignies, L.; Brechet, Y.; Audier, M.; Livet, F.; Louchet, F.; Sainfort, P.

    1993-01-01

    An alloy from the 7000 serie obtained by the Osprey process has been studied both from the microstructural (TEM, SAXS) and from the mechanical viewpoint. The modelling of the mechanical properties and of their anisotropy was performed using both models from physical metallurgy and a self consistent elastoplastic model. (orig.)

  19. Halloysite reinforced epoxy composites with improved mechanical properties

    Directory of Open Access Journals (Sweden)

    Saif Muhammad Jawwad

    2016-03-01

    Full Text Available Halloysite nanotubes (HNTs reinforced epoxy composites with improved mechanical properties were prepared. The prepared HNTs reinforced epoxy composites demonstrated improved mechanical properties especially the fracture toughness and flexural strength. The flexural modulus of nanocomposite with 6% mHNTs loading was 11.8% higher than that of neat epoxy resin. In addition, the nanocomposites showed improved dimensional stability. The prepared halloysite reinforced epoxy composites were characterized by thermal gravimetric analysis (TGA. The improved properties are attributed to the unique characteristics of HNTs, uniform dispersion of reinforcement and interfacial coupling.

  20. Multiscale simulation of mechanical properties of TiNb alloy

    Science.gov (United States)

    Nikonov, A. Yu.

    2017-12-01

    The article presents a numerical simulation of the mechanical properties of a Ti-Nb β-alloy on three different scales. The ab-initio approach is used to estimate the concentrations of the Ti alloy with required elastic properties. On the basis of molecular dynamics simulation, we calculate the adhesive force between individual particles of the alloy. The calculated dependence is implemented within the movable cellular automata method to determine the mechanical properties of Ti-Nb depending on the interparticle free space.

  1. Radiation Improved Mechanical and Thermal Property of PP/HDPE

    International Nuclear Information System (INIS)

    Chaisupaditsin, M.; Thammit, C.; Techakiatkul, C.

    1998-01-01

    The mechanical properties, thermal properties and gel contents of PP-irradiated HDPE blends were studied. HDPE was gamma irradiated in the dose range of 10-30 kGy. The ratios of polymer blends of 30PP:70HDPE was mixed by a twin screw extruder at speed of 50 rpm. Irradiated HDPE with 30 kGy showed the highest gel contents. The blends ratio of 30PP:70HDPE (30 kGy) shows better heat resistance than the blends with non-irradiated HDPE. With increasing the radiation doses, the mechanical properties of the blends were improved

  2. Mechanical properties of austenitic stainless steels in sodium

    International Nuclear Information System (INIS)

    Lloyd, G.J.

    1978-03-01

    A detailed review of the mechanical properties of austenitic stainless steels in liquid sodium is presented. Consideration has been given to the influence of the of the impurities in reactor sodium and metallurgical variables upon the stress rupture life, the low cycle fatigue and combined creep/fatigue resistance, elastic-plastic crack propagation rates, the high cycle fatigue life, tensile properties and fracture toughness. The effects of exposure to contaminated sodium prior to testing are also discussed. Examples of the success of mechanistic interpretations of materials behaviour in sodium are given and additionally, the extent to which mechanical properties in sodium may be predicted with the use of appropriate data. (author)

  3. Mechanical Properties and Durability of "Waterless Concrete"

    Science.gov (United States)

    Toutanji, Houssam; Grugel, Richard N.

    2008-01-01

    Waterless concrete consists of molten elementary sulfur and aggregate. The aggregates in lunar environment will be lunar rocks and soil. Sulfur is present on the Moon in Troilite soil (FeS) and by oxidation soil iron and sulfur can be produced. Iron can be used to reinforce the sulfur concrete. Sulfur concrete specimens were cycled between liquid nitrogen (approximately 191 C) and room temperature (approximately 21 C) to simulate exposure to a lunar environment. Cycled and control specimens were subsequently tested in compression at room temperatures (approximately 21 C) and approximately 101 C. Test results showed that due to temperature cycling, compressive strength of cycled specimens was 20% of those non-cycled. Microscopic examination of the fracture surfaces from the cycled samples showed clear de-bonding of the sulfur from the aggregate material whereas it was seen well bonded in those non-cycled. This reduction in strength can be attributed to the large differences in thermal coefficients of expansion of the materials constituting the concrete which promoted cracking. Similar sulfur concrete mixtures were strengthened with short and long glass fibers. The glass fibers from lunar regolith simulant was melted in a 25 cc Pt-Rh crucible in a Sybron Thermoline high temperature MoSi2 furnace at melting temperatures of 1450 to 1600 C for times of 30 min to 1 hour. Glass fibers were cast from the melt into graphite crucibles and were annealed for a couple of hours at 600 C. Glass fibers and small rods were pulled from the melt. The glass melt wets the ceramic rod and long continuous glass fibers were easily hand drawn. The glass fibers were immediately coated with a protective polymer to maintain the mechanical strength. The glass fibers were used to reinforce sulfur concrete plated to improve the flexural strength of the sulfur concrete. Prisms beams strengthened with glass fibers were tested in 4-point bending test. Beams strengthened with glass fiber showed to

  4. Evaluating Molecular Properties Involved in Transport of Small Molecules in Stratum Corneum: A Quantitative Structure-Activity Relationship for Skin Permeability

    Directory of Open Access Journals (Sweden)

    Chen-Peng Chen

    2018-04-01

    Full Text Available The skin permeability (Kp defines the rate of a chemical penetrating across the stratum corneum. This value is widely used to quantitatively describe the transport of molecules in the outermost layer of epidermal skin and indicate the significance of skin absorption. This study defined a Kp quantitative structure-activity relationship (QSAR based on 106 chemical substances of Kp measured using human skin and interpreted the molecular interactions underlying transport behavior of small molecules in the stratum corneum. The Kp QSAR developed in this study identified four molecular descriptors that described the molecular cyclicity in the molecule reflecting local geometrical environments, topological distances between pairs of oxygen and chlorine atoms, lipophilicity, and similarity to antineoplastics in molecular properties. This Kp QSAR considered the octanol-water partition coefficient to be a direct influence on transdermal movement of molecules. Moreover, the Kp QSAR identified a sub-domain of molecular properties initially defined to describe the antineoplastic resemblance of a compound as a significant factor in affecting transdermal permeation of solutes. This finding suggests that the influence of molecular size on the chemical’s skin-permeating capability should be interpreted with other relevant physicochemical properties rather than being represented by molecular weight alone.

  5. Evaluating Molecular Properties Involved in Transport of Small Molecules in Stratum Corneum: A Quantitative Structure-Activity Relationship for Skin Permeability.

    Science.gov (United States)

    Chen, Chen-Peng; Chen, Chan-Cheng; Huang, Chia-Wen; Chang, Yen-Ching

    2018-04-15

    The skin permeability ( Kp ) defines the rate of a chemical penetrating across the stratum corneum. This value is widely used to quantitatively describe the transport of molecules in the outermost layer of epidermal skin and indicate the significance of skin absorption. This study defined a Kp quantitative structure-activity relationship (QSAR) based on 106 chemical substances of Kp measured using human skin and interpreted the molecular interactions underlying transport behavior of small molecules in the stratum corneum. The Kp QSAR developed in this study identified four molecular descriptors that described the molecular cyclicity in the molecule reflecting local geometrical environments, topological distances between pairs of oxygen and chlorine atoms, lipophilicity, and similarity to antineoplastics in molecular properties. This Kp QSAR considered the octanol-water partition coefficient to be a direct influence on transdermal movement of molecules. Moreover, the Kp QSAR identified a sub-domain of molecular properties initially defined to describe the antineoplastic resemblance of a compound as a significant factor in affecting transdermal permeation of solutes. This finding suggests that the influence of molecular size on the chemical's skin-permeating capability should be interpreted with other relevant physicochemical properties rather than being represented by molecular weight alone.

  6. Increased Oxidation as an Additional Mechanism Underlying Reduced Clot Permeability and Impaired Fibrinolysis in Type 2 Diabetes

    Directory of Open Access Journals (Sweden)

    Anna Lados-Krupa

    2015-01-01

    Full Text Available Aims. We sought to investigate whether enhanced oxidation contributes to unfavorable fibrin clot properties in patients with diabetes. Methods. We assessed plasma fibrin clot permeation (Ks, a measure of the pore size in fibrin networks and clot lysis time induced by recombinant tissue plasminogen activator (CLT in 163 consecutive type 2 diabetic patients (92 men and 71 women aged 65 ± 8.8 years with a mean glycated hemoglobin (HbA1c of 6.8%. We also measured oxidative stress markers, including nitrotyrosine, the soluble form of receptor for advanced glycation end products (sRAGE, 8-iso-prostaglandin F2α (8-iso-PGF2α, oxidized low-density lipoprotein (oxLDL, and advanced glycation end products (AGE. Results. There were inverse correlations between Ks and nitrotyrosine, sRAGE, 8-iso-PGF2α, and oxLDL. CLT showed a positive correlation with oxLDL and nitrotyrosine but not with other oxidation markers. All these associations remained significant for Ks after adjustment for fibrinogen, disease duration, and HbA1c (all P<0.05, while oxLDL was the only independent predictor of CLT. Conclusions. Our study shows that enhanced oxidative stress adversely affects plasma fibrin clot properties in type 2 diabetic patients, regardless of disease duration and glycemia control.

  7. Chronic alcohol abuse in men alters bone mechanical properties by affecting both tissue mechanical properties and microarchitectural parameters.

    Science.gov (United States)

    Cruel, M; Granke, M; Bosser, C; Audran, M; Hoc, T

    2017-06-01

    Alcohol-induced secondary osteoporosis in men has been characterized by higher fracture prevalence and a modification of bone microarchitecture. Chronic alcohol consumption impairs bone cell activity and results in an increased fragility. A few studies highlighted effects of heavy alcohol consumption on some microarchitectural parameters of trabecular bone. But to date and to our knowledge, micro- and macro-mechanical properties of bone of alcoholic subjects have not been investigated. In the present study, mechanical properties and microarchitecture of trabecular bone samples from the iliac crest of alcoholic male patients (n=15) were analyzed and compared to a control group (n=8). Nanoindentation tests were performed to determine the tissue's micromechanical properties, micro-computed tomography was used to measure microarchitectural parameters, and numerical simulations provided the apparent mechanical properties of the samples. Compared to controls, bone tissue from alcoholic patients exhibited an increase of micromechanical properties at tissue scale, a significant decrease of apparent mechanical properties at sample scale, and significant changes in several microarchitectural parameters. In particular, a crucial role of structure model index (SMI) on mechanical properties was identified. 3D microarchitectural parameters are at least as important as bone volume fraction to predict bone fracture risk in the case of alcoholic patients. Copyright © 2017 Elsevier Masson SAS. All rights reserved.

  8. Mechanical and corrosion properties of AA8011 sheets and foils:

    OpenAIRE

    Asanović, Vanja; Dalijić, Kemal; Radonjić, Dragan

    2006-01-01

    The mechanical and corrosion properties of a twin-roll cast Al-Fe-Si aluminum alloy with 0.74 % Fe and 0.52 % Si (AA8011) were investigated. The influence of the thermo-mehanical processing route on the mechanical behavior of AA8011 sheets was determined. Comparisons were made with AA3003 and A199.5 sheets. The restoration of the mechanical properties was used in the analysis of the recrystallization behavior of the twin-roll cast AA8011 alloy deformed under cold-working conditions and subseq...

  9. Mechanical Properties of Isotactic Polypropylene Modified with Thermoplastic Potato Starch

    Science.gov (United States)

    Knitter, M.; Dobrzyńska-Mizera, M.

    2015-05-01

    In this paper selected mechanical properties of isotactic polypropylene (iPP) modified with potato starch have been presented. Thermoplastic starch (TPS) used as a modifier in the study was produced from potato starch modified with glycerol. Isotactic polypropylene/thermoplastic potato starch composites (iPP/TPS) that contained 10, 30, 50 wt.% of modified starch were examined using dynamic mechanical-thermal analysis, static tensile, Brinell hardness, and Charpy impact test. The studies indicated a distinct influence of a filler content on the mechanical properties of composites in comparison with non-modified polypropylene.

  10. Mechanical properties and morphology of poly(etheretherKetone)

    Science.gov (United States)

    Cebe, Peggy; Chung, Shirley; Gupta, Amitava; Hong, Su-Don

    1987-01-01

    Mechanical properties and morphology of poly(etheretherketone) (PEEK) were studied for samples having different thermal histories. Isothermal and rate-dependent crystallization were studied to ascertain the relationship between crystallinity/morphology and processing condition. Degree of crystallinity and microstructure were controlled by cooling the melt at different rates, ranging from quenching to slowly cooling, and by annealing amorphous material above the glass transition temperature Tg. It is found that degree of crystallinity was not as important as processing history in determining the room temperature mechanical properties. Samples with the same degree of crystallinity had very different tensile properties, depending on rate of cooling from the melt. All samples yielded by shear band formation and necked down. Quenched films had the largest breaking strains, drawing to 270 percent. Slowly cooled films exhibited ductile failure at relatively low strains. Best combined mechanical properties were obtained from semicrystalline films cooled at intermediate rates from the melt.

  11. [Studies on the mechanical properties of the knee ligament].

    Science.gov (United States)

    Kubotera, D

    1987-04-01

    To study mechanical properties of the knee ligaments, tension tests at various speeds were performed on the knee of a dog with only the collateral ligament. The results showed that the tensile force was greater in high speed than in low speed test. The difference may be caused in a viscous property of the ligament. The mechanical properties of ligaments can therefore be treated as those of viscoelastic materials and expressed by a modified Voigt model consisting of a non-linear spring element and a dash pot component. Observations regarding the ultrastructure of human knee ligaments using an electron scanning microscope revealed wavy bundles of collagen fiber connected with coarse fibers like network running in parallel with the long axis as the main structure. The above structure and properties were considered to be the decisive factors in the mechanical actions of the knee ligament.

  12. Mechanical properties of experimental composites with different calcium phosphates fillers.

    Science.gov (United States)

    Okulus, Zuzanna; Voelkel, Adam

    2017-09-01

    Calcium phosphates (CaPs)-containing composites have already shown good properties from the point of view of dental restorative materials. The purpose of this study was to examine the crucial mechanical properties of twelve hydroxyapatite- or tricalcium phosphate-filled composites. The raw and surface-treated forms of both CaP fillers were applied. As a reference materials two experimental glass-containing composites and one commercial dental restorative composite were applied. Nano-hardness, elastic modulus, compressive, flexural and diametral tensile strength of all studied materials were determined. Application of statistical methods (one-way analysis of variance and cluster agglomerative analysis) allowed for assessing the similarities between examined materials according to the values of studied parameters. The obtained results show that in almost all cases the mechanical properties of experimental CaPs-composites are comparable or even better than mechanical properties of examined reference materials. Copyright © 2017 Elsevier B.V. All rights reserved.

  13. Lithophysal Rock Mass Mechanical Properties of the Repository Host Horizon

    International Nuclear Information System (INIS)

    D. Rigby

    2004-01-01

    The purpose of this calculation is to develop estimates of key mechanical properties for the lithophysal rock masses of the Topopah Spring Tuff (Tpt) within the repository host horizon, including their uncertainties and spatial variability. The mechanical properties to be characterized include an elastic parameter, Young's modulus, and a strength parameter, uniaxial compressive strength. Since lithophysal porosity is used as a surrogate property to develop the distributions of the mechanical properties, an estimate of the distribution of lithophysal porosity is also developed. The resulting characterizations of rock parameters are important for supporting the subsurface design, developing the preclosure safety analysis, and assessing the postclosure performance of the repository (e.g., drift degradation and modeling of rockfall impacts on engineered barrier system components)

  14. Correlation between the mechanical and histological properties of liver tissue.

    Science.gov (United States)

    Yarpuzlu, Berkay; Ayyildiz, Mehmet; Tok, Olgu Enis; Aktas, Ranan Gulhan; Basdogan, Cagatay

    2014-01-01

    In order to gain further insight into the mechanisms of tissue damage during the progression of liver diseases as well as the liver preservation for transplantation, an improved understanding of the relation between the mechanical and histological properties of liver is necessary. We suggest that this relation can only be established truly if the changes in the states of those properties are investigated dynamically as a function of post mortem time. In this regard, we first perform mechanical characterization experiments on three bovine livers to investigate the changes in gross mechanical properties (stiffness, viscosity, and fracture toughness) for the preservation periods of 5, 11, 17, 29, 41 and 53h after harvesting. Then, the histological examination is performed on the samples taken from the same livers to investigate the changes in apoptotic cell count, collagen accumulation, sinusoidal dilatation, and glycogen deposition as a function of the same preservation periods. Finally, the correlation between the mechanical and histological properties is investigated via the Spearman's Rank-Order Correlation method. The results of our study show that stiffness, viscosity, and fracture toughness of bovine liver increase as the preservation period is increased. These macroscopic changes are very strongly correlated with the increase in collagen accumulation and decrease in deposited glycogen level at the microscopic level. Also, we observe that the largest changes in mechanical and histological properties occur after the first 11-17h of preservation. © 2013 Elsevier Ltd. All rights reserved.

  15. Characterization of porosity in support of mechanical property analysis

    International Nuclear Information System (INIS)

    Price, R.H.; Martin, R.J. III; Boyd, P.J.

    1993-01-01

    The general applicability of laboratory data for engineering purposes is a prime concern for the design and licensing of a potential repository of high level nuclear waste at Yucca Mountain. In order for the results of experiments to be applicable to the repository scale, the data must be scaled to in situ size and conditions. Previous laboratory investigations of tuff have shown that porosity has a dominant, general effect on mechanical properties. As a result, it is very important for the interpretation of mechanical property data that porosity is measured on each sampled test. Porosity alone, however, does not address all of the issues important to mechanical behavior. Variability in size and distribution of pore space produces significantly different mechanical properties. A nondestructive technique for characterizing the internal structure of the sample prior to testing is being developed and the results are being analyzed. The information obtained from this technique can help in both qualitative and quantitative interpretation of test results

  16. The Effect of Bedding Structure on Mechanical Property of Coal

    Directory of Open Access Journals (Sweden)

    Zetian Zhang

    2014-01-01

    Full Text Available The mechanical property of coal, influencing mining activity considerably, is significantly determined by the natural fracture distributed within coal mass. In order to study the effecting mechanism of bedding structure on mechanical property of coal, a series of uniaxial compression tests and mesoscopic tests have been conducted. The experimental results show that the distribution characteristic of calcite particles, which significantly influences the growth of cracks and the macroscopic mechanical properties of coal, is obviously affected by the bedding structure. Specifically, the uniaxial compression strength of coal sample is mainly controlled by bedding structure, and the average peak stress of specimens with axes perpendicular to the bedding planes is 20.00 MPa, which is 2.88 times the average amount of parallel ones. The test results also show a close relationship between the bedding structure and the whole deformation process under uniaxial loading.

  17. Mechanical properties used for the qualification of transport casks

    International Nuclear Information System (INIS)

    Salzbrenner, R.; Crenshaw, T.B.; Sorenson, K.B.

    1993-01-01

    The qualification process that should be sufficient for qualification of a specific cask (material/geometry combination) has been examined. The prototype cask should be tested to determine its overall variation in microstructure, chemistry, and mechanical properties. This prototype may also be subjected to 'proof testing' to demonstrate the validity of the design analysis (including the mechanical properties used in the analysis). The complete mechanical property mapping does not necessarily have to precede the proof testing (i.e., portions of the cask which experience only low (elastic) loads during the drop test are suitable for mechanical test specimens). The behavior of the prototype cask and the production casks are linked by assuring that each cask possesses at least the minimum level of one or more critical mechanical properties. This may be done by measuring the properties of interest directly, or by relying on a secondary measurement (such as subsize mechanical test results or microstructure/compositional measurements) which has been statistically correlated to the critical properties. The database required to show the correlation between the secondary measurement and the valid design property may be established by tests on the material from the prototype cask. The production controls must be demonstrated as being adequate to assure that a uniform product is produced. The testing of coring (or test block or prolongation) samples can only be viewed as providing a valid link to the benchmark results provided by the prototype cask if the process used to create follow-on casks remains essentially similar. The MOSAIK Test Program has demonstrated the qualification method through the benchmarking stage. The program did not establish for qualifying serial production casks through, for example, a correlation between small specimen parameters and valid design fracture toughness properties. Such a correlation would require additional experimental work. (J.P.N.)

  18. Modeling the mechanics of cancer: effect of changes in cellular and extra-cellular mechanical properties.

    Science.gov (United States)

    Katira, Parag; Bonnecaze, Roger T; Zaman, Muhammad H

    2013-01-01

    Malignant transformation, though primarily driven by genetic mutations in cells, is also accompanied by specific changes in cellular and extra-cellular mechanical properties such as stiffness and adhesivity. As the transformed cells grow into tumors, they interact with their surroundings via physical contacts and the application of forces. These forces can lead to changes in the mechanical regulation of cell fate based on the mechanical properties of the cells and their surrounding environment. A comprehensive understanding of cancer progression requires the study of how specific changes in mechanical properties influences collective cell behavior during tumor growth and metastasis. Here we review some key results from computational models describing the effect of changes in cellular and extra-cellular mechanical properties and identify mechanistic pathways for cancer progression that can be targeted for the prediction, treatment, and prevention of cancer.

  19. Mechanical properties of jennite: A theoretical and experimental study

    Energy Technology Data Exchange (ETDEWEB)

    Moon, Juhyuk, E-mail: juhyuk.moon@stonybrook.edu [Civil Engineering Program, Department of Mechanical Engineering, Stony Brook University, NY 11794 (United States); Yoon, Seyoon [School of Engineering, Kings College, University of Aberdeen, Aberdeen AB24 3UE (United Kingdom); Monteiro, Paulo J.M. [Department of Civil and Environmental Engineering, University of California, Berkeley, CA 94720 (United States)

    2015-05-15

    The objective of this study is to determine the mechanical properties of jennite. To date, several hypotheses have been proposed to predict the structural properties of jennite. For the first time as reported herein, the isothermal bulk modulus of jennite was measured experimentally. Synchrotron-based high-pressure x-ray diffraction experiments were performed to observe the variation of lattice parameters under pressure. First-principles calculations were applied to compare with the experimental results and predict additional structural properties. Accurately measured isothermal bulk modulus herein (K{sub 0} = 64(2) GPa) and the statistical assessment on experimental and theoretical results suggest reliable mechanical properties of shear and Young's modulus, Poisson's ratio, and elastic tensor coefficients. Determination of these fundamental structural properties is the first step toward greater understanding of calcium–silicate–hydrate, as well as provides a sound foundation for forthcoming atomic level simulations.

  20. Combined meso-scale modeling and experimental investigation of the effect of mechanical damage on the transport properties of cementitious composites

    Science.gov (United States)

    Raghavan, Balaji; Niknezhad, Davood; Bernard, Fabrice; Kamali-Bernard, Siham

    2016-09-01

    The transport properties of cementitious composites such as concrete are important indicators of their durability, and are known to be heavily influenced by mechanical loading. In the current work, we use meso-scale hygro-mechanical modeling with a morphological 3D two phase mortar-aggregate model, in conjunction with experimentally obtained properties, to investigate the coupling between mechanical loading and damage and the permeability of the composite. The increase in permeability of a cylindrical test specimen at 28% aggregate fraction during a uniaxial displacement-controlled compression test at 85% of the peak load was measured using a gas permeameter. The mortar's mechanical behavior is assumed to follow the well-known compression damaged plasticity (CDP) model with isotropic damage, at varying thresholds, and obtained from different envelope curves. The damaged intrinsic permeability of the mortar evolves according to a logarithmic matching law with progressive loading. We fit the matching law parameters to the experimental result for the test specimen by inverse identification using our meso-scale model. We then subject a series of virtual composite specimens to quasi-static uniaxial compressive loading with varying boundary conditions to obtain the simulated damage and strain evolutions, and use the damage data and the previously identified parameters to determine the evolution of the macroscopic permeability tensor for the specimens, using a network model. We conduct a full parameter study by varying aggregate volume fraction, granulometric distribution, loading/boundary conditions and "matching law" parameters, as well as for different strain-damage thresholds and uniaxial loading envelope curves. Based on this study, we propose Avrami equation-based upper and lower bounds for the evolution of the damaged permeability of the composite.

  1. Amperometric NOx-sensor for Combustion Exhaust Gas Control. Studies on transport properties and catalytic activity of oxygen permeable ceramic membranes

    International Nuclear Information System (INIS)

    Romer, E.W.J.

    2001-01-01

    materials must be co-firable and, hence, match in thermal, chemical and mechanical behaviour. A number of studies on different mixed oxygen ion/electron conducting materials is described in this thesis. Emphasis is put on the demands of the targeted sensor application, in which these materials are used as mixed conducting dense ceramic membranes. In Chapter 2, a series of perovskite materials is studied. The general composition is ABO 3-δ (A = Gd, Pr, Y; B = Mn, Cr, Fe), being partially doped with Ca 2+ and Sr 2+ on the A-site to create mobile oxygen vacancies. The main focus of the work presented is on the measurement of catalytic activities towards NOx and the ionic conductivities of the selected materials. In Chapter 3, the preparation and characterisation of a material with the overall composition of Gd 0.7 Ca 0.3 CoO x is described. Dual phase composite membranes are the subject of investigations presented in Chapters 4-7. The main advantage of these type of materials is that their properties can be tailored to meet the demands imposed by the sensor design. Emphasis is on the preparation of the materials, characterisation by SEM-EDX, XRD, catalytic activity and measurement of ionic/electronic conductivities. In Chapter 4, dual phase composites of composition Gd 0.7 Ca 0.3 CoO x /Ce 0.8 Gd 0.2 O 2- are studied. Composites ZrO 2 /In 2 O 3 and ZrO 2 /ITO are subject to the investigations reported in Chapters 5 and 6, respectively. Finally, in Chapter 7, composite Au/YSZ and Au/Ce 0.8 Gd 0.2 O 2- membranes are studied. Finally, in Chapter 8 a summary of the results is given together with recommendations for future research

  2. Enhancing mechanical properties of chitosan films via modification with vanillin.

    Science.gov (United States)

    Zhang, Zhi-Hong; Han, Zhong; Zeng, Xin-An; Xiong, Xia-Yu; Liu, Yu-Jia

    2015-11-01

    The vanillin/chitosan composite films were prepared using the solvent evaporation method. The properties of the films including optical property, water vapor permeability (WVP), tensile strength (TS) and elongation at break (%E) were studied to investigate the effect of cross-linking agent of vanillin on chitosan films by thermogravimetric analysis (TGA), scanning electron microscopy (SEM), X-ray diffraction (XRD) and Fourier transform infrared spectrum (FT-IR). Results showed that the TS of composite films increased by 53.3% and the WVP decreased by 36.5% compared with pure chitosan film that were due to the formation of the dense network structure by FT-IR spectra. There were almost no changes of the thermal stability of the composite films compared with the pure chitosan film by TGA analysis. In addition, from the SEM images, it could be seen that the film with addition of vanillin with 0.5-10% concentration exhibited good compatibility. Copyright © 2015 Elsevier B.V. All rights reserved.

  3. Physical, mechanical and barrier properties of corn starch films incorporated with plant essential oils.

    Science.gov (United States)

    Ghasemlou, Mehran; Aliheidari, Nahal; Fahmi, Ronak; Shojaee-Aliabadi, Saeedeh; Keshavarz, Behnam; Cran, Marlene J; Khaksar, Ramin

    2013-10-15

    Corn starch-based films are inherently brittle and lack the necessary mechanical integrity for conventional packaging. However, the incorporation of additives can potentially improve the mechanical properties and processability of starch films. In this work two essential oils, Zataria multiflora Boiss (ZEO) or Mentha pulegium (MEO) at three levels (1%, 2% and 3% (v/v)), were incorporated into starch films using a solution casting method to improve the mechanical and water vapor permeability (WVP) properties and to impart antimicrobial activity. Increasing the content of ZEO or MEO from 2% to 3% (v/v) increased values for elongation at break from 94.38% to 162.45% and from 53.34% to 107.71% respectively, but did not significantly change tensile strength values of the films. The WVP properties of the films decreased from 7.79 to 3.37 or 3.19 g mm m(-2) d(-1) kPa(-1) after 3% (v/v) ZEO or MEO incorporation respectively. The oxygen barrier properties were unaffected at the 1% and 2% (v/v) oil concentration used but oxygen transmission increased with 3% (v/v) for both formulations. The films' color became slightly yellow as the levels of ZEO or MEO were increased although transparency was maintained. Both films demonstrated antimicrobial activity with films containing ZEO more effective against Escherichia coli and Staphylococcus aureus than those containing MEO. These results suggest that ZEO and MEO have the potential to be directly incorporated into corn starch to prepare antimicrobial biodegradable films for various food packaging applications. Copyright © 2013 Elsevier Ltd. All rights reserved.

  4. Suitability of Torrent Permeability Tester to measure air-permeability of covercrete

    Energy Technology Data Exchange (ETDEWEB)

    Andrade, C.; Gonzales-Gasca, C. [Institute of Construction Sciences ' Eduardo Torroja' , Madrid (Spain); Torrent, R. [Portland Cement Institute, (Argentina)

    2000-07-01

    Suitability of the Torrent Permeability Tester (TPT) to measure the permeability of covercrete to air, both in the laboratory and the field, is investigated, and test results obtained in laboratory studies are discussed. The tests performed included the determination of air permeability (TPT method), oxygen permeability (Cembureau method) and capillary suction, rapid chloride permeability test (ASTM C 1202), as well as a one-year carbonation depth test. Concrete specimens of various compositions and curing regimes were used in the tests; the gas-permeability tests were repeated on the same specimens after 28 days, than again at 6 months and 12 months. Test results confirmed the suitability of the TPT as a useful tool in the characterization of the quality the of concrete cover. It was found to be sensitive to changes in concrete quality; repeatable for sensitive properties such as gas permeability ; also, it was found to correlate well with other durability-related properties. 10 refs., 8 tabs., 8 figs.

  5. Metal Additive Manufacturing: A Review of Mechanical Properties

    Science.gov (United States)

    Lewandowski, John J.; Seifi, Mohsen

    2016-07-01

    This article reviews published data on the mechanical properties of additively manufactured metallic materials. The additive manufacturing techniques utilized to generate samples covered in this review include powder bed fusion (e.g., EBM, SLM, DMLS) and directed energy deposition (e.g., LENS, EBF3). Although only a limited number of metallic alloy systems are currently available for additive manufacturing (e.g., Ti-6Al-4V, TiAl, stainless steel, Inconel 625/718, and Al-Si-10Mg), the bulk of the published mechanical properties information has been generated on Ti-6Al-4V. However, summary tables for published mechanical properties and/or key figures are included for each of the alloys listed above, grouped by the additive technique used to generate the data. Published values for mechanical properties obtained from hardness, tension/compression, fracture toughness, fatigue crack growth, and high cycle fatigue are included for as-built, heat-treated, and/or HIP conditions, when available. The effects of test orientation/build direction on properties, when available, are also provided, along with discussion of the potential source(s) (e.g., texture, microstructure changes, defects) of anisotropy in properties. Recommendations for additional work are also provided.

  6. Mechanical and irradiation properties of zirconium alloys irradiated in HANARO

    International Nuclear Information System (INIS)

    Kwon, Oh Hyun; Eom, Kyong Bo; Kim, Jae Ik; Suh, Jung Min; Jeon, Kyeong Lak

    2011-01-01

    These experimental studies are carried out to build a database for analyzing fuel performance in nuclear power plants. In particular, this study focuses on the mechanical and irradiation properties of three kinds of zirconium alloy (Alloy A, Alloy B and Alloy C) irradiated in the HANARO (High-flux Advanced Neutron Application Reactor), one of the leading multipurpose research reactors in the world. Yield strength and ultimate tensile strength were measured to determine the mechanical properties before and after irradiation, while irradiation growth was measured for the irradiation properties. The samples for irradiation testing are classified by texture. For the irradiation condition, all samples were wrapped into the capsule (07M-13N) and irradiated in the HANARO for about 100 days (E > 1.0 MeV, 1.1 10 21 n/cm 2 ). These tests and results indicate that the mechanical properties of zirconium alloys are similar whether unirradiated or irradiated. Alloy B has shown the highest yield strength and tensile strength properties compared to other alloys in irradiated condition. Even though each of the zirconium alloys has a different alloying content, this content does not seem to affect the mechanical properties under an unirradiated condition and low fluence. And all the alloys have shown the tendency to increase in yield strength and ultimate tensile strength. Transverse specimens of each of the zirconium alloys have a slightly lower irradiation growth tendency than longitudinal specimens. However, for clear analysis of texture effects, further testing under higher irradiation conditions is needed

  7. Bone biopsy needles. Mechanical properties, needle design and specimen quality

    International Nuclear Information System (INIS)

    Keulers, Annika; Penzkofer, T.; Cunha-Cruz, V.C.; Bruners, P.; Helmholtz Inst. fuer biomedizinische Technik, Aachen; Braunschweig, T.; Schmitz-Rode, T.; Mahnken, A.; Helmholtz Inst. fuer biomedizinische Technik, Aachen

    2011-01-01

    To quantitatively analyze differences in mechanical properties, needle design including signs of wear, subjective handling and specimen quality of bone biopsy needles. Materials and Methods: In this study 19 different bone biopsy systems (total 38; 2 /type) were examined. With each biopsy needle five consecutive samples were obtained from vertebral bodies of swine. During puncture a force-torques sensor measured the mechanical properties and subjective handling was assessed. Before and after each biopsy the needles were investigated using a profile projector and signs of wear were recorded. Afterwards, a pathologist semi-quantitatively examined the specimen regarding sample quality. The overall evaluation considered mechanical properties, needle wear, subjective handling and sample quality. Differences were assessed for statistical significance using ANOVA and t-test. Results: Needle diameter (p = 0.003) as well as needle design (p = 0.008) affect the mechanical properties significantly. Franseen design is significantly superior to other needle designs. Besides, length reduction recorded by the profile projector, as a quality criterion showed notable distinctions in between the needle designs. Conclusion: Bone biopsy needles vary significantly in performance. Needle design has an important influence on mechanical properties, handling and specimen quality. Detailed knowledge of those parameters would improve selecting the appropriate bone biopsy needle. (orig.)

  8. Thermo-mechanical Properties of Upper Jurassic (Malm) Carbonate Rock Under Drained Conditions

    Science.gov (United States)

    Pei, Liang; Blöcher, Guido; Milsch, Harald; Zimmermann, Günter; Sass, Ingo; Huenges, Ernst

    2018-01-01

    The present study aims to quantify the thermo-mechanical properties of Neuburger Bankkalk limestone, an outcrop analog of the Upper Jurassic carbonate formation (Germany), and to provide a reference for reservoir rock deformation within future enhanced geothermal systems located in the Southern German Molasse Basin. Experiments deriving the drained bulk compressibility C were performed by cycling confining pressure p c between 2 and 50 MPa at a constant pore pressure p p of 0.5 MPa after heating the samples to defined temperatures between 30 and 90 °C. Creep strain was then measured after each loading and unloading stage, and permeability k was obtained after each creep strain measurement. The drained bulk compressibility increased with increasing temperature and decreased with increasing differential pressure p d = p c - p p showing hysteresis between the loading and unloading stages above 30 °C. The apparent values of the indirectly calculated Biot coefficient α ind containing contributions from inelastic deformation displayed the same temperature and pressure dependencies. The permeability k increased immediately after heating and the creep rates were also temperature dependent. It is inferred that the alteration of the void space caused by temperature changes leads to the variation of rock properties measured under isothermal conditions while the load cycles applied under isothermal conditions yield additional changes in pore space microstructure. The experimental results were applied to a geothermal fluid production scenario to constrain drawdown and time-dependent effects on the reservoir, overall, to provide a reference for the hydromechanical behavior of geothermal systems in carbonate, and more specifically, in Upper Jurassic lithologies.

  9. The fracture properties and toughening mechanisms of bone and dentin

    Science.gov (United States)

    Koester, Kurt John

    The mechanical properties of bone and dentin and in particular their fracture properties, are the subject of intense research. The relevance of these properties is increasing as our population ages and fracture incidence impacts the lives of a greater portion of the population. A robust framework is needed to understand the fracture properties of bone and dentin to guide researchers as they attempt to characterize the effects of aging, disease, and pharmaceutical treatments on the properties of these mineralized tissues. In the present work, this framework is provided and applied to human bone, human dentin, and animal bone. In situ electron microscopy was also used to identify the salient toughening mechanisms in bone and dentin. It was found that bone and dentin are extrinsically toughened materials and consequently their fracture properties are best characterized utilizing a crack-growth resistance approach. A description of the different mechanical measurements commonly employed when using small animal models (rats and mice) to evaluate the influence of drug therapies on bone fragility is provided. A study where these properties were measured for a large population of wild-type rats and mice was also conducted. Given my findings, it was determined that for the most complete understanding of small animal bone it was necessary to measure strength and toughness. Strength measurements probe the flaw distribution and toughness measurements to evaluate the resistance to facture in the presence of a single dominant worst-case flaw.

  10. Size Effect of Defects on the Mechanical Properties of Graphene

    Science.gov (United States)

    Park, Youngho; Hyun, Sangil

    2018-03-01

    Graphene, a two-dimensional material, has been studied and utilized for its excellent material properties. In reality, achieving a pure single-crystalline structure in graphene is difficult, so usually graphene may have various types of defects in it. Vacancies, Stone-Wales defects, and grain boundaries can drastically change the material properties of graphene. Graphene with vacancy defects has been of interest because it is a two-dimensional analogy of three-dimensional porous materials. It has efficient material properties, and can function as a part of modern devices. The mechanical properties have been studied by using molecular dynamics for either a single vacancy defect with various sizes or multiple vacancy defects with same defect ratios. However, it is not clear which one has more influence on the mechanical properties between the size of the defects and the defect ratio. Therefore, we investigated the hole-size effect on the mechanical properties of single-crystalline graphene at various defect ratios. A void defect with large size can have a rather high tensile modulus with a low fracture strain compared to a void defect with small size. We numerically found that the tensile properties of scattered single vacancies is similar to that of amorphous graphene. We suspect that this is due to the local orbital change of the carbon atoms near the boundary of the void defects, so-called the interfacial phase.

  11. Modelling the Effect of Weave Structure and Fabric Thread Density on Mechanical and Comfort Properties of Woven Fabrics

    Directory of Open Access Journals (Sweden)

    Maqsood Muhammad

    2016-09-01

    Full Text Available The paper investigates the effects of weave structure and fabric thread density on the comfort and mechanical properties of various test fabrics woven from polyester/cotton yarns. Three different weave structures, that is, 1/1 plain, 2/1 twill and 3/1 twill, and three different fabric densities were taken as input variables whereas air permeability, overall moisture management capacity, tensile strength and tear strength of fabrics were taken as response variables and a comparison is made of the effect of weave structure and fabric density on the response variables. The results of fabric samples were analysed in Minitab statistical software. The coefficients of determinations (R-sq values of the regression equations show a good predictive ability of the developed statistical models. The findings of the study may be helpful in deciding appropriate manufacturing specifications of woven fabrics to attain specific comfort and mechanical properties.

  12. Morphological, mechanical, barrier and properties of films based on acetylated starch and cellulose from barley.

    Science.gov (United States)

    El Halal, Shanise Lisie Mello; Colussi, Rosana; Biduski, Bárbara; Evangelho, Jarine Amaral do; Bruni, Graziella Pinheiro; Antunes, Mariana Dias; Dias, Alvaro Renato Guerra; Zavareze, Elessandra da Rosa

    2017-01-01

    Biodegradable films of native or acetylated starches with different concentrations of cellulose fibers (0%, 10% and 20%) were prepared. The films were characterized by morphological, mechanical, barrier, and thermal properties. The tensile strength of the acetylated starch film was lower than those of the native starch film, without fibers. The addition of fibers increased the tensile strength and decreased the elongation and the moisture of native and acetylated starches films. The acetylated starch film showed higher water solubility when compared to native starch film. The addition of cellulose fibers reduced the water solubility of the acetylated starch film. The films reinforced with cellulose fiber exhibited a higher initial decomposition temperature and thermal stability. The mechanical, barrier, solubility, and thermal properties are factors which direct the type of the film application in packaging for food products. The films elaborated with acetylated starches of low degree of substitution were not effective in a reduction of the water vapor permeability. The addition of the cellulose fiber in acetylated and native starches films can contribute to the development of more resistant films to be applied in food systems that need to maintain their integrity. © 2016 Society of Chemical Industry. © 2016 Society of Chemical Industry.

  13. Impacts of Hydrate Distribution on the Hydro-Thermo-Mechanical Properties of Hydrate-Bearing Sediments

    Science.gov (United States)

    Dai, S.; Seol, Y.

    2015-12-01

    In general, hydrate makes the sediments hydraulically less conductive, thermally more conductive, and mechanically stronger; yet the dependency of these physical properties on hydrate saturation varies with hydrate distribution and morphology. Hydrate distribution in sediments may cause the bulk physical properties of their host sediments varying several orders of magnitude even with the same amount of hydrate. In natural sediments, hydrate morphology is inherently governed by the burial depth and the grain size of the host sediments. Compare with patchy hydrate, uniformly distributed hydrate is more destructive to fluid flow, yet leads to higher gas and water permeability during hydrate dissociation due to the easiness of forming percolation paths. Water and hydrate have similar thermal conductivity values; the bulk thermal conductivity of hydrate-bearing sediments depends critically on gas-phase saturation. 60% of gas saturation may result in evident thermal conductivity drop and hinder further gas production. Sediments with patchy hydrate yield lower stiffness than that with cementing hydrate but higher stiffness than that with pore filling and loading bearing hydrate. Besides hydrate distribution, the stress state and loading history also play an important role in the mechanical behavior of hydrate-bearing sediments.

  14. Mechanical and water barrier properties of agar/κ-carrageenan/konjac glucomannan ternary blend biohydrogel films.

    Science.gov (United States)

    Rhim, Jong-Whan; Wang, Long-Feng

    2013-07-01

    Multicomponent hydrogel films composed of agar, κ-carrageenan, konjac glucomannan powder, and nanoclay (Cloisite(®) 30B) were prepared and their mechanical and water barrier properties such as water vapor permeability (WVP), water contact angle (CA), water solubility (WS), water uptake ratio (WUR), water vapor uptake ratio (WVUR) were determined. Mechanical, water vapor barrier, and water resistance properties of the ternary blend film exhibited middle range of individual component films, however, they increased significantly after formation of nanocomposite with the clay. Especially, the water holding capacity of the ternary blend biopolymer films increased tremendously, from 800% to 1681% of WUR for agar and κ-carrageenan films up to 5118% and 5488% of WUR for the ternary blend and ternary blend nanocomposite films, respectively. Water vapor adsorption behavior of films was also tested by water vapor adsorption kinetics and water vapor adsorption isotherms test. Preliminary test result for fresh spinach packaging revealed that the ternary blend biohydrogel films had a high potential for the use as an antifogging film for packaging highly respiring agricultural produce. In addition, the ternary blend nanocomposite film showed an antimicrobial activity against Gram-positive bacteria, Listeria monocytogenes. Copyright © 2013 Elsevier Ltd. All rights reserved.

  15. Study of Biodegradability and Mechanical Properties of Polyvinyl Alcohol (PVA Reinforced Celloluse Nanofiber (CNF

    Directory of Open Access Journals (Sweden)

    shobo salehpour

    2018-02-01

    Full Text Available The aim of this study was to improve the properties of polyvinyl alcohol (PVA by using cellulose nanofibers (CNF as a reinforcement. In order to improve the compatibility and miscibility with PVA matrix, freeze drying method was applied. The nanocomposites based on PVA with values 5, 10, 20 and 30wt% of CNF were prepared by freeze-drying and the effect of CNF addition on the mechanical and dynamical mechanical properties, moisture sorption, barrier and biodegradability of the nanocomposites was studied. The tensile strength and elastic modulus of PVA films were improved by the addition of CNF. The nanocomposite with 10wt% nano-fibers had the highest tensile strength and lowest modulus of elasticity and the elongation at break. The results indicated that the storage modulus (E′ of PVA was considerably improved with the introduction of CNF into - polymer matrix. The water vapor permeability decreased from 7.31 to 2.1×10-7 g/m. h. Pa as the CNF percentage increased from 0 to 30%. Also the presence of cellulose nanofibers improved moisture sorption of polyvinyl alcohol. The weight loss of PVA films increased 60% with addition of 30wt% CNF after 90 days of exposure in soil

  16. Permeability of cork to gases.

    Science.gov (United States)

    Faria, David P; Fonseca, Ana L; Pereira, Helen; Teodoro, Orlando M N D

    2011-04-27

    The permeability of gases through uncompressed cork was investigated. More than 100 samples were assessed from different plank qualities to provide a picture of the permeability distribution. A novel technique based on a mass spectrometer leak detector was used to directly measure the helium flow through the central area of small disks 10 mm in diameter and 2 mm thick. The permeability for nitrogen, oxygen, and other gases was measured by the pressure rise technique. Boiled and nonboiled cork samples from different sections were evaluated. An asymmetric frequency distribution ranging 3 orders of magnitude (roughly from 1 to 1000 μmol/(cm·atm·day)) for selected samples without macroscopic defects was found, having a peak below 100 μmol/(cm·atm·day). Correlation was found between density and permeability: higher density samples tend to show lower permeability. However, boiled cork showed a mean lower permeability despite having a lower density. The transport mechanism of gases through cork was also examined. Calculations suggest that gases permeate uncompressed cork mainly through small channels between cells under a molecular flow regime. The diameter of such channels was estimated to be in the range of 100 nm, in agreement with the plasmodesmata size in the cork cell walls.

  17. Developments in permeable and low permeability barriers

    International Nuclear Information System (INIS)

    Jefferis, S.A.; Norris, G.H.; Thomas, A.O.

    1997-01-01

    The concept of the reactive treatment zone whereby pollutants are attenuated as they move along a pathway in the ground has enabled a re-thinking of many of the concepts of containment. In particular it offers the potential for the control of the flux from a contaminated area by controlling the contaminant concentration in the pathway(s) as well as or instead of using a low permeability barrier. The paper outlines the basic concepts of the reactive treatment zone and the use of permeable and low permeability reactive systems. The paper then gives a case history of the installation of a permeable barrier using an in-situ reaction chamber

  18. Mechanical Properties of Organic Semiconductors for Stretchable, Highly Flexible, and Mechanically Robust Electronics.

    Science.gov (United States)

    Root, Samuel E; Savagatrup, Suchol; Printz, Adam D; Rodriquez, Daniel; Lipomi, Darren J

    2017-05-10

    Mechanical deformability underpins many of the advantages of organic semiconductors. The mechanical properties of these materials are, however, diverse, and the molecular characteristics that permit charge transport can render the materials stiff and brittle. This review is a comprehensive description of the molecular and morphological parameters that govern the mechanical properties of organic semiconductors. Particular attention is paid to ways in which mechanical deformability and electronic performance can coexist. The review begins with a discussion of flexible and stretchable devices of all types, and in particular the unique characteristics of organic semiconductors. It then discusses the mechanical properties most relevant to deformable devices. In particular, it describes how low modulus, good adhesion, and absolute extensibility prior to fracture enable robust performance, along with mechanical "imperceptibility" if worn on the skin. A description of techniques of metrology precedes a discussion of the mechanical properties of three classes of organic semiconductors: π-conjugated polymers, small molecules, and composites. The discussion of each class of materials focuses on molecular structure and how this structure (and postdeposition processing) influences the solid-state packing structure and thus the mechanical properties. The review concludes with applications of organic semiconductor devices in which every component is intrinsically stretchable or highly flexible.

  19. A Novel Method of Mechanical Oxidation of CNT for Polymer Nanocomposite Application: Evaluation of Mechanical, Dynamic Mechanical, and Rheological Properties

    Directory of Open Access Journals (Sweden)

    Priyanka Pandey

    2014-01-01

    Full Text Available A new approach of oxidation of carbon nanotubes has been used to oxidize the CNTs. A comparative aspect of the mechanical oxidation and acid oxidation process has been established. FTIR analysis and titration method have shown the higher feasibility of the mechanical oxidation method to oxidize the CNTs. Comparatively less damage to the CNTs has been observed in case of mechanically oxidized as compared to acid oxidized CNTs. The mechanical properties of the nanocomposites reinforced with the acid oxidized CNT (ACNT and mechanically oxidized CNTs (McCNT were analyzed and relatively higher properties in the nanocomposites reinforced with McCNT were noticed. The less degree of entanglement in the McCNTs was noticed as compared to ACNTs. The dynamic mechanical analysis of the nanocomposites revealed much improved load transfer capability in the McCNT reinforced composites. Further, the rheological properties of the nanocomposites revealed the higher performance of McCNT reinforced composites.

  20. Manupulation of microstructure, phase evolution and mechanical properties by devitrification of andesite for use as proppant

    Science.gov (United States)

    Koseski, Ryan P.

    Small, roughly spherical ceramic particles, approximately 1mm in size are used for a number of applications including casting sands, catalysts, and cement fillers. The oil and natural gas industry utilizes such materials in tonnage quantities yearly as extraction aids. Particles intended for this application are referred to as proppants. Proppants are composed of materials that differ by density, strength and cost, and are selected on a site by site basis. Recently, competing usage and depletion of reserves of one of the most popular category of proppant materials, sintered aluminosilicates (e.g. kaolinite, bauxite) have driven the need for alternative raw materials for proppant manufacturing. Andesite, a by-product of mining operations in the south-west United States was identified as an abundant, readily available, and low cost alternative proppant material that can be fused and net-shaped into a glass which when crystallized results in microstructures which may offer substantial toughening and fracture characteristics which may serve to their advantage for use as proppants that do not decrease the permeability ("blind") the particle bed. This study addressed the devitrification behavior and its role on the mechanical properties of andesite-based glass-ceramic spheres for use as proppants. Timetemperature- transformation studies were performed to evaluate the devitrification behavior of andesite glass. Crystalline phase evolution and microstructural development were evaluated using quantitative x-ray diffraction, scanning electron microscopy, differential thermal analysis, and spectrophotometry. The andesite glass devitrification commenced with the precipitation of iron oxides (magnetite) which served as seeds for the epitaxial growth of dendritic pyroxenes. Mechanical properties, such as diametral compressive strength, fracture toughness, hardness, and fracture morphology were correlated with crystalline phase evolution. Selected heat treatments resulting in the

  1. Effect of γ-irradiation on the physical and mechanical properties of kefiran biopolymer film.

    Science.gov (United States)

    Shahabi-Ghahfarrokhi, Iman; Khodaiyan, Faramarz; Mousavi, Mohammad; Yousefi, Hossein

    2015-03-01

    In this study, the effect of different γ-ray dosages (3, 6, and 9 kGy) on the functional properties of kefiran biopolymer was investigated. The obtained results showed that increasing γ-ray dosage brought about an increase in the tensile strength of film specimens up to three-times. However, elongation at break, and tensile energy to break of γ-irradiated kefiran films decreased in the wake of increasing γ-ray dosage. γ-Irradiation could improve surface hydrophobicity, sensitivity of kefiran film specimens to water, and water vapor permeability, but yellowness of films increased, simultaneously. XRD spectrum confirmed increased crystallinity of γ-irradiated films. Melting point of films was constant but glass transition temperature decreased drastically at high γ-ray dosage (9 kGy). ATR-FTIR analysis confirmed that γ-ray engendered no changes in chemical functional groups. According to the result, a mechanism was proposed to percept the effects of γ-irradiation on kefiran biopolymer and its role on the functional properties of kefiran film. Hence, the functional properties of kefiran films were depend on the ratio of cross-linkages between polymer chains and produced mono and disaccharide by γ-irradiation. Copyright © 2014 Elsevier B.V. All rights reserved.

  2. Investigation of Mechanical and Electromagnetic Interference Shielding Properties of Nickel-CFRP Textile Composites

    Science.gov (United States)

    Tugirumubano, Alexandre; Vijay, Santhiyagu Joseph; Go, Sun Ho; Kwac, Lee Ku; Kim, Hong Gun

    2018-04-01

    The most common materials used for electromagnetic interference shielding are metals and their alloys. However, those materials are heavy and highly reflective. In order to eliminate or reduce the intensity of wave radiation in their working environment, lightweight materials that have interference shielding properties are needed. In this paper, nickel wire mesh yarns (warps) were woven into carbon fibers-reinforced plastic yarns (wefts) to produce metal-carbon textile composite materials. The plain weave and 2/2 twill weave techniques were used, and the woven fabrics were laminated to manufacture experimental test samples. The nickel, which has high magnetic permeability and good electric conductivity, and carbon fibers, which have good electrical, thermal and mechanical properties, were used together to achieve the desired properties. The shielding effectiveness of each sample was investigated using a network analyzer connected with coaxial transmission line test in accordance with ASTM 4935-99 standard, with the frequencies ranging from 500 MHz to 1.5 GHz. Here, the plain weave structure showed higher shielding effectiveness than twill weave. The absorption losses for both materials were relatively greater than reflection losses. In reference to the orientation of wire mesh yarns about the loading axis, the tensile strengths in the transversal direction were 19.04 and 16.34% higher than the tensile strengths in longitudinal direction for plain weave and twill weave, respectively. The fractography analysis with SEM showed a ductile fracture of wire mesh and brittle fracture of epoxy matrix and carbon fibers.

  3. Investigation of Mechanical and Electromagnetic Interference Shielding Properties of Nickel-CFRP Textile Composites

    Science.gov (United States)

    Tugirumubano, Alexandre; Vijay, Santhiyagu Joseph; Go, Sun Ho; Kwac, Lee Ku; Kim, Hong Gun

    2018-05-01

    The most common materials used for electromagnetic interference shielding are metals and their alloys. However, those materials are heavy and highly reflective. In order to eliminate or reduce the intensity of wave radiation in their working environment, lightweight materials that have interference shielding properties are needed. In this paper, nickel wire mesh yarns (warps) were woven into carbon fibers-reinforced plastic yarns (wefts) to produce metal-carbon textile composite materials. The plain weave and 2/2 twill weave techniques were used, and the woven fabrics were laminated to manufacture experimental test samples. The nickel, which has high magnetic permeability and good electric conductivity, and carbon fibers, which have good electrical, thermal and mechanical properties, were used together to achieve the desired properties. The shielding effectiveness of each sample was investigated using a network analyzer connected with coaxial transmission line test in accordance with ASTM 4935-99 standard, with the frequencies ranging from 500 MHz to 1.5 GHz. Here, the plain weave structure showed higher shielding effectiveness than twill weave. The absorption losses for both materials were relatively greater than reflection losses. In reference to the orientation of wire mesh yarns about the loading axis, the tensile strengths in the transversal direction were 19.04 and 16.34% higher than the tensile strengths in longitudinal direction for plain weave and twill weave, respectively. The fractography analysis with SEM showed a ductile fracture of wire mesh and brittle fracture of epoxy matrix and carbon fibers.

  4. Microfibrous silver-coated polymeric scaffolds with tunable mechanical properties

    KAUST Repository

    Kalakonda, Parvathalu.; Aldhahri, Musab A.; Abdel-wahab, Mohamed Shaaban; Tamayol, Ali; Moghaddam, K. Mollazadeh; Ben Rached, Fathia; Pain, Arnab; Khademhosseini, Ali; Memic, Adnan; Chaieb, Saharoui

    2017-01-01

    Electrospun scaffolds of poly(glycerol sebacate)/poly(ε-caprolactone) (PGS/PCL) have been used for engineered tissues due to their desirable thermal and mechanical properties as well as their tunable degradability. In this paper, we fabricated micro-fibrous scaffolds from a composite of PGS/PCL using a standard electrospinning method and coated them with silver (Ag). The low temperature coating method prevented substrate melting and the Ag coating decreases the pore size and increases the diameter of fibers which resulted in enhanced thermal and mechanical properties. We further compared the mechanical properties of the composite fibrous scaffolds with different thicknesses of Ag coated scaffolds. The composite fibrous scaffold with a 275 nm Ag coating showed higher tensile modulus (E) and ultimate tensile strength (UTS) without any post-processing treatment. Lastly, potential controlled release of the Ag coating from the composite fibrous scaffolds could present interesting biomedical applications.

  5. Improvement of the mechanical properties of reinforced aluminum foam samples

    Science.gov (United States)

    Formisano, A.; Barone, A.; Carrino, L.; De Fazio, D.; Langella, A.; Viscusi, A.; Durante, M.

    2018-05-01

    Closed-cell aluminum foam has attracted increasing attention due to its very interesting properties, thanks to which it is expected to be used as both structural and functional material. A research challenge is the improvement of the mechanical properties of foam-based structures adopting a reinforced approach that does not compromise their lightness. Consequently, the aim of this research is the fabrication of enhanced aluminum foam samples without significantly increasing their original weight. In this regard, cylindrical samples with a core of closed-cell aluminum foam and a skin of fabrics and grids of different materials were fabricated in a one step process and were mechanically characterized, in order to investigate their behaviour and to compare their mechanical properties to the ones of the traditional foam.

  6. Development the Mechanical Properties of (AL-Li-Cu Alloy

    Directory of Open Access Journals (Sweden)

    Ihsan Kadhom AlNaimi

    2017-11-01

    Full Text Available The aim of this research is to develop mechanical properties of a new aluminium-lithium-copper alloy. This alloy prepared under control atmosphere by casting in a permanent metal mould. The microstructure was examined and mechanical properties were tested before and after heat treatment to study the influence of heat treatment on its mechanical properties including; modulus of elasticity, tensile strength, impact, and fatigue. The results showed that the modulus of elasticity of the prepared alloy is higher than standard alloy about 2%. While the alloy that heat treated for 6 h and cooled in water, then showed a higher ultimate tensile stress comparing with as-cast alloy. The homogenous heat treatment gives best fatigue behaviour comparing with as-cast and other heat treatment alloys. Also, the impact test illustrates that the homogeneous heat treatment alloy gives the highest value.

  7. Microfibrous silver-coated polymeric scaffolds with tunable mechanical properties

    KAUST Repository

    Kalakonda, Parvathalu.

    2017-07-07

    Electrospun scaffolds of poly(glycerol sebacate)/poly(ε-caprolactone) (PGS/PCL) have been used for engineered tissues due to their desirable thermal and mechanical properties as well as their tunable degradability. In this paper, we fabricated micro-fibrous scaffolds from a composite of PGS/PCL using a standard electrospinning method and coated them with silver (Ag). The low temperature coating method prevented substrate melting and the Ag coating decreases the pore size and increases the diameter of fibers which resulted in enhanced thermal and mechanical properties. We further compared the mechanical properties of the composite fibrous scaffolds with different thicknesses of Ag coated scaffolds. The composite fibrous scaffold with a 275 nm Ag coating showed higher tensile modulus (E) and ultimate tensile strength (UTS) without any post-processing treatment. Lastly, potential controlled release of the Ag coating from the composite fibrous scaffolds could present interesting biomedical applications.

  8. Phase imaging of mechanical properties of live cells (Conference Presentation)

    Science.gov (United States)

    Wax, Adam

    2017-02-01

    The mechanisms by which cells respond to mechanical stimuli are essential for cell function yet not well understood. Many rheological tools have been developed to characterize cellular viscoelastic properties but these typically require direct mechanical contact, limiting their throughput. We have developed a new approach for characterizing the organization of subcellular structures using a label free, noncontact, single-shot phase imaging method that correlates to measured cellular mechanical stiffness. The new analysis approach measures refractive index variance and relates it to disorder strength. These measurements are compared to cellular stiffness, measured using the same imaging tool to visualize nanoscale responses to flow shear stimulus. The utility of the technique is shown by comparing shear stiffness and phase disorder strength across five cellular populations with varying mechanical properties. An inverse relationship between disorder strength and shear stiffness is shown, suggesting that cell mechanical properties can be assessed in a format amenable to high throughput studies using this novel, non-contact technique. Further studies will be presented which include examination of mechanical stiffness in early carcinogenic events and investigation of the role of specific cellular structural proteins in mechanotransduction.

  9. AC magnetic properties of the soft magnetic composites based on Supermalloy nanocrystalline powder prepared by mechanical alloying

    Energy Technology Data Exchange (ETDEWEB)

    Neamtu, B.V., E-mail: bogdan.neamtu@stm.utcluj.ro [Materials Science and Engineering Department, Technical University of Cluj-Napoca, 400614 Cluj-Napoca (Romania); Institut Neel, CNRS/Universite J. Fourier, BP166, 38042 Grenoble, Cedex 9 (France); Geoffroy, O. [Institut Neel, CNRS/Universite J. Fourier, BP166, 38042 Grenoble, Cedex 9 (France); Grenoble Electrical Engineering, University J. Fourier, BP 46, F-38402 Saint-Martin d' Heres Cedex (France); Chicinas, I. [Materials Science and Engineering Department, Technical University of Cluj-Napoca, 400614 Cluj-Napoca (Romania); Isnard, O. [Institut Neel, CNRS/Universite J. Fourier, BP166, 38042 Grenoble, Cedex 9 (France)

    2012-05-25

    Highlights: Black-Right-Pointing-Pointer Nanocrystalline soft magnetic composites were obtained. Black-Right-Pointing-Pointer The cutting frequency of the produced nanocrystalline SMC exceeds 100 kHz. Black-Right-Pointing-Pointer A long annealing at low temperature leads to an improvement of the permeability (12%). - Abstract: The preparation and characterization of the nanocrystalline soft magnetic composite core based on Supermalloy powder obtained via mechanical alloying route are presented. The AC magnetic properties of the compacts were determined in frequency range from 100 Hz to 100 kHz for flux densities of 0.05 and 0.1 T. Composite materials were obtained by covering the Supermalloy particles with a polymer binder, then compacted into toroidal shape and finally polymerized. It is found that an increase of the compacting pressure from 600 MPa to 800 MPa leads to an increase of the compacts permeability by more than 8%. Also, reducing the polymer content from 2 wt.% to 0.5 wt.% leads to an increase of the magnetic losses (at 100 kHz and 0.1 T) by 380%. The removal of the stresses induced during compaction has been accomplished by a heat treatment at 170 Degree-Sign C for 120 h. This leads to a significant increase (12%) of the relative initial permeability of the compacts.

  10. Pressing Speed, Specific Pressure and Mechanical Properties of Aluminium Cast

    Directory of Open Access Journals (Sweden)

    Gaspar S.

    2016-06-01

    Full Text Available Recent research in the process of aluminum alloy die castings production, which is nowadays deeply implemented into the rapidly growing automobile, shipping and aircraft industries, is aimed at increasing the useful qualitative properties of the die casting in order to obtain its high mechanical properties at acceptable economic cost. Problem of technological factors of high pressure die casting has been a subject of worldwide research (EU, US, Japan, etc.. The final performance properties of die castings are subjected to a large number of technological factors. The main technological factors of high pressure die casting are as follows: plunger pressing speed, specific (increase pressure, mold temperature as well as alloy temperature. The contribution discusses the impact of the plunger pressing speed and specific (increase pressure on the mechanical properties of the casting aluminum alloy.

  11. Mechanical Properties for Reliability Analysis of Structures in Glassy Carbon

    CERN Document Server

    Garion, Cédric

    2014-01-01

    Despite its good physical properties, the glassy carbon material is not widely used, especially for structural applications. Nevertheless, its transparency to particles and temperature resistance are interesting properties for the applications to vacuum chambers and components in high energy physics. For example, it has been proposed for fast shutter valve in particle accelerator [1] [2]. The mechanical properties have to be carefully determined to assess the reliability of structures in such a material. In this paper, mechanical tests have been carried out to determine the elastic parameters, the strength and toughness on commercial grades. A statistical approach, based on the Weibull’s distribution, is used to characterize the material both in tension and compression. The results are compared to the literature and the difference of properties for these two loading cases is shown. Based on a Finite Element analysis, a statistical approach is applied to define the reliability of a structural component in gl...

  12. Structure–mechanics property relationship of waste derived biochars

    Energy Technology Data Exchange (ETDEWEB)

    Das, Oisik, E-mail: odas566@aucklanduni.ac.nz [Department of Civil and Environmental Engineering, University of Auckland, Auckland 1142 (New Zealand); Sarmah, Ajit K., E-mail: a.sarmah@auckland.ac.nz [Department of Civil and Environmental Engineering, University of Auckland, Auckland 1142 (New Zealand); Bhattacharyya, Debes, E-mail: d.bhattacharyya@auckland.ac.nz [Department of Mechanical Engineering, Center for Advanced Composite Materials, University of Auckland, Auckland 1142 (New Zealand)

    2015-12-15

    The widespread applications of biochar in agriculture and environmental remediation made the scientific community ignore its mechanical properties. Hence, to examine the scope of biochar's structural applications, its mechanical properties have been investigated in this paper through nanoindentation technique. Seven waste derived biochars, made under different pyrolysis conditions and from diverse feedstocks, were studied via nanoindentation, infrared spectroscopy, X–ray crystallography, thermogravimetry, and electron microscopy. Following this, an attempt was made to correlate the biochars' hardness/modulus with reaction conditions and their chemical properties. The pine wood biochar made at 900 °C and 60 min residence time was found to have the highest hardness and elastic modulus of 4.29 and 25.01 GPa, respectively. It was shown that a combination of higher heat treatment (≥ 500 °C) temperature and longer residence time (~ 60 min) increases the values of hardness and modulus. It was further realized that pyrolysis temperature was a more dominant factor than residence time in determining the final mechanical properties of biochar particles. The degree of aromaticity and crystallinity of the biochar were also correlated with higher values of hardness and modulus. - Highlights: • Characterization was done on waste based biochars which included nanoindentation. • Pine saw dust biochar made at 900 °C for 60 min had highest hardness/modulus. • Combination of temperature/residence time affect biochar's mechanical propertie.s • Aromaticity and crystallinity positively affected biochar's mechanical properties.

  13. The Mechanical Properties of Recycled Polyethylene-Polyethylene Terephthalate Composites

    Directory of Open Access Journals (Sweden)

    Ehsan Avazverdi

    2015-02-01

    Full Text Available Polyethylene terephthalate (PET, one of the thermoplastic polymers, is encountered with arduous problems in its recycling. After recycling, its mechanical properties drop dramatically and therefore it cannot be used to produce the products as virgin PET does. Polyethylene is a thermoplastic polymer which can be easily recycled using the conventional recycling processes. The decreased mechanical properties of virgin polyethylene due to the environmental factors can be improved by reinforcing fillers. In this paper, we studied the effects of adding recycled polyethylene terephthalate (rPET as a filler, in various amounts with different sizes, on the physical and mechanical properties of recycled polyethylene. Composite samples were prepared using an internal mixer at temperature 185°C, well below rPET melting point (250°C, and characterized by their mechanical properties. To improve the compatibility between different components, PE grafted with maleic anhydride was added as a coupling agent in all the compositions under study. The mechanical properties of the prepared samples were performed using the tensile strength, impact strength, surface hardness and melt flow index (MFI tests. To check the dispersity of the polyethylene terephthalate powder in the polyethylene matrix, light microscopy was used. The results showed that the addition of rPET improved the tensile energy, tensile modulus and surface hardness of the composites while reduced the melt flow index, elongation-at-yield, tensile strength and fracture energy of impact test. We could conclude that with increasing rPET percentage in the recycled polyethylene matrix, the composite became brittle, in other words it decreased the plastic behavior of recycled polyethylene. Decreasing particle size led to higher surface contacts, increased the mechanical properties and made the composite more brittle. The light microscopy micrographs of the samples showed a good distribution of small r

  14. Exterior difference systems and invariance properties of discrete mechanics

    International Nuclear Information System (INIS)

    Xie Zheng; Xie Duanqiang; Li Hongbo

    2008-01-01

    Invariance properties describe the fundamental physical laws in discrete mechanics. Can those properties be described in a geometric way? We investigate an exterior difference system called the discrete Euler-Lagrange system, whose solution has one-to-one correspondence with solutions of discrete Euler-Lagrange equations, and use it to define the first integrals. The preservation of the discrete symplectic form along the discrete Hamilton phase flows and the discrete Noether's theorem is also described in the language of difference forms

  15. Molecular packing and magnetic properties of lithium naphthalocyanine crystals: hollow channels enabling permeability and paramagnetic sensitivity to molecular oxygen

    Science.gov (United States)

    Pandian, Ramasamy P.; Dolgos, Michelle; Marginean, Camelia; Woodward, Patrick M.; Hammel, P. Chris; Manoharan, Periakaruppan T.; Kuppusamy, Periannan

    2009-01-01

    The synthesis, structural framework, magnetic and oxygen-sensing properties of a lithium naphthalocyanine (LiNc) radical probe are presented. LiNc was synthesized in the form of a microcrystalline powder using a chemical method and characterized by electron paramagnetic resonance (EPR) spectroscopy, magnetic susceptibility, powder X-ray diffraction analysis, and mass spectrometry. X-Ray powder diffraction studies revealed a structural framework that possesses long, hollow channels running parallel to the packing direction. The channels measured approximately 5.0 × 5.4 Å2 in the two-dimensional plane perpendicular to the length of the channel, enabling diffusion of oxygen molecules (2.9 × 3.9 Å2) through the channel. The powdered LiNc exhibited a single, sharp EPR line under anoxic conditions, with a peak-to-peak linewidth of 630 mG at room temperature. The linewidth was sensitive to surrounding molecular oxygen, showing a linear increase in pO2 with an oxygen sensitivity of 31.2 mG per mmHg. The LiNc microcrystals can be further prepared as nano-sized crystals without the loss of its high oxygen-sensing properties. The thermal variation of the magnetic properties of LiNc, such as the EPR linewidth, EPR intensity and magnetic susceptibility revealed the existence of two different temperature regimes of magnetic coupling and hence differing columnar packing, both being one-dimensional antiferromagnetic chains but with differing magnitudes of exchange coupling constants. At a temperature of ∼50 K, LiNc crystals undergo a reversible phase transition. The high degree of oxygen-sensitivity of micro- and nano-sized crystals of LiNc, combined with excellent stability, should enable precise and accurate measurements of oxygen concentration in biological systems using EPR spectroscopy. PMID:19809598

  16. Effects of humidity on the mechanical properties of gecko setae.

    Science.gov (United States)

    Prowse, Michael S; Wilkinson, Matt; Puthoff, Jonathan B; Mayer, George; Autumn, Kellar

    2011-02-01

    We tested the hypothesis that an increase in relative humidity (RH) causes changes in the mechanical properties of the keratin of adhesive gecko foot hairs (setae). We measured the effect of RH on the tensile deformation properties, fracture, and dynamic mechanical response of single isolated tokay gecko setae and strips of the smooth lamellar epidermal layer. The mechanical properties of gecko setae were strongly affected by RH. The complex elastic modulus (measured at 5 Hz) of a single seta at 80% RH was 1.2 GPa, only 39% of the value when dry. An increase in RH reduced the stiffness and increased the strain to failure. The loss tangent increased significantly with humidity, suggesting that water absorption produces a transition to a more viscous type of deformation. The influence of RH on the properties of the smooth epidermal layer was comparable with that of isolated seta, with the exception of stress at rupture. These values were two to four times greater for the setae than for the smooth layer. The changes in mechanical properties of setal keratin were consistent with previously reported increases in contact forces, supporting the hypothesis that an increase in RH softens setal keratin, which increases adhesion and friction. Copyright © 2010 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

  17. Measurement of the mechanical properties of layered systems

    International Nuclear Information System (INIS)

    Blank, E.

    2002-01-01

    Thin films for integrated electronic circuitry, packaging and small structures in micro-electromechanical systems (MEMS) as well as protective coatings require mechanical testing to control fabrication processes, guarantee product quality and establish data bases for engineering purposes. They generally escape classical materials testing owing to their small size in at least one dimension and their incorporation into larger structures. The fact that material properties change in the micro- and nanometer range when sample dimensions reach the scale of defect structures, implies that sample and probe size become part of the property evaluation process. Although research into the mechanical behaviour of thin films and small structures now is established, the fundamentals of mechanical testing continue to be identified while there is a growing need for methods allowing to measure intrinsic material properties. This lecture will focus on the mechanics of thin film and small volume structures and review recently developed testing techniques for measuring materials properties, particularly indentation, bulge and bend testing. The effect of specimen and probe geometry on property evaluation will be discussed. The use of Raman spectroscopy for residual stress measurement will be illustrated. (Author)

  18. Correlation between fuel structure and mechanical properties of UO2

    International Nuclear Information System (INIS)

    Blank, H.; Mandler, R.; Matzke, H.; Routbort, J.; Werner, P.

    1982-10-01

    The relation between the structure of a UO 2 fuel and its mechanical properties are discussed and illustrated for particular types of UO 2 by measurements of fracture surface energy, hardness, fracture stress and of compressive deformation at 1870 and 1970 0 K. This gives the background for treating the question whether it is possible to find a simple experimental method for correlating the mechanical properties of UO 2 before irradiation with those after various irradiation histories. Hardness measurements might be such a method if combined with a detailed structural analysis and sufficient knowledge about the irradiation history

  19. Mechanical properties of welded joints of duplex steels

    International Nuclear Information System (INIS)

    Kawiak, M.; Nowacki, J.

    2003-01-01

    The paper presents the study results of mechanical properties of duplex steels UNS S31803 welded joints as well as duplex and NV A36 steels welded joints. They have ben welded by FCAW method in CO 2 using FCW 2205-H flux-cored wire. The joints have been subjected: tensile tests, impact tests, bending tests, hardness tests and metallographic investigations. The influence of welding parameters and mechanical properties of the joints was appreciated. The welding method assured high tensile strength of the joints (approximately 770 MPa) and high impact strength of the welds (approximately 770 J). All samples were broken outside of welds. (author)

  20. The mechanism and properties of acid-coagulated milk gels

    Directory of Open Access Journals (Sweden)

    Chanokphat Phadungath

    2005-03-01

    Full Text Available Acid-coagulated milk products such as fresh acid-coagulated cheese varieties and yogurt areimportant dairy food products. However, little is known regarding the mechanisms involved in gel formation, physical properties of acid gels, and the effects of processing variables such as heat treatment and gelation temperature on the important physical properties of acid milk gels. This paper reviews the modern concepts of possible mechanisms involved in the formation of particle milk gel aggregation, along with recent developments including the use of techniques such as dynamic low amplitude oscillatory rheology to observe the gel formation process, and confocal laser scanning microscopy to monitor gel microstructure.

  1. Mechanical Properties of Plug Welds after Micro-Jet Cooling

    OpenAIRE

    Hadryś D.

    2016-01-01

    New technology of micro-jet welding could be regarded as a new way to improve mechanical properties of plug welds. The main purpose of that paper was analyzing of mechanical properties of plug welds made by MIG welding method with micro-jet cooling. The main way for it was comparison of plug welds made by MIG welding method with micro-jet cooling and plug welds made by ordinary MIG welding method. It is interesting for steel because higher amount of acicular ferrite (AF) in weld metal deposit...

  2. The factors influencing microstructure and mechanical properties of ADI

    Directory of Open Access Journals (Sweden)

    A. Vaško

    2009-01-01

    Full Text Available The paper deals with the influence of different conditions of isothermal heat treatment on microstructure and mechanical properties of austempered ductile iron (ADI. Different temperature of isothermal transformation of austenite and different holding time at this temperature were used for heat treatment of specimens. The microstructure of specimens after casting and after heat treatment was evaluated by STN EN ISO 945 and by image analysis (using Lucia software. Mechanical properties were evaluated by the tensile test, the Rockwell hardness test and fatigue tests.

  3. Computer simulations of the mechanical properties of metals

    DEFF Research Database (Denmark)

    Schiøtz, Jakob; Vegge, Tejs

    1999-01-01

    Atomic-scale computer simulations can be used to gain a better understanding of the mechanical properties of materials. In this paper we demonstrate how this can be done in the case of nanocrystalline copper, and give a brief overview of how simulations may be extended to larger length scales....... Nanocrystline metals are metals with grain sizes in the nanometre range, they have a number of technologically interesting properties such as much increased hardness and yield strength. Our simulations show that the deformation mechanisms are different in these materials than in coarse-grained materials...

  4. Ultrasound-based testing of tendon mechanical properties

    DEFF Research Database (Denmark)

    Seynnes, O R; Bojsen-Møller, J.; Albracht, K

    2015-01-01

    In the past 20 years, the use of ultrasound-based methods has become a standard approach to measure tendon mechanical properties in vivo. Yet the multitude of methodological approaches adopted by various research groups probably contribute to the large variability of reported values. The technique......, or signal synchronization; and 2) in physiological considerations related to the viscoelastic behavior or length measurements of tendons. Hence, the purpose of the present review is to assess and discuss the physiological and technical aspects connected to in vivo testing of tendon mechanical properties...

  5. Mechanical properties of timber from wind damaged Norway spruce

    DEFF Research Database (Denmark)

    Hoffmeyer, Preben

    2003-01-01

    A storm may subject a tree to such bending stresses that extensive compression damage develops in the lee side. The tree may survive the wind load or it may be thrown. However, the damage is inherent and it may be of a magnitude to influence the mechanical properties of boards sawn from the stem....... The paper reports on a investigation of the relation between degree of damage and mechanical proper-ties of sawn timber from wind damaged Norway spruce. The project included about 250 bolts from wind damaged trees. The majority of bolts were cut to deliver a full-diameter plank containing the pith...

  6. Mechanical Properties and Durability of CNT Cement Composites

    Directory of Open Access Journals (Sweden)

    María del Carmen Camacho

    2014-02-01

    Full Text Available In the present paper, changes in mechanical properties of Portland cement-based mortars due to the addition of carbon nanotubes (CNT and corrosion of embedded steel rebars in CNT cement pastes are reported. Bending strength, compression strength, porosity and density of mortars were determined and related to the CNT dosages. CNT cement paste specimens were exposed to carbonation and chloride attacks, and results on steel corrosion rate tests were related to CNT dosages. The increase in CNT content implies no significant variations of mechanical properties but higher steel corrosion intensities were observed.

  7. Antimicrobial Effects of 7,8-Dihydroxy-6-Methoxycoumarin and 7-Hydroxy-6-Methoxycoumarin Analogues against Foodborne Pathogens and the Antimicrobial Mechanisms Associated with Membrane Permeability.

    Science.gov (United States)

    Yang, Ji-Yeon; Park, Jun-Hwan; Lee, Myung-Ji; Lee, Ji-Hoon; Lee, Hoi-Seon

    2017-10-03

    The antimicrobial effects of 7,8-dihydroxy-6-methoxycoumarin and 7-hydroxy-6-methoxycoumarin isolated from Fraxinus rhynchophylla bark and of their structural analogues were determined in an attempt to develop natural antimicrobial agents against the foodborne pathogens Escherichia coli, Bacillus cereus, Staphylococcus intermedius, and Listeria monocytogenes. To elucidate the relationship between structure and antimicrobial activity for the coumarin analogues, isolated constituents and their structural analogues were evaluated against foodborne pathogens. Based on the culture plate inhibition zones and MICs, 6,7-dimethoxycoumarin, 7,8-dihydroxy-6-methoxycoumarin, 7-hydroxy-6-methoxycoumarin, and 7-methoxycoumarin, containing a methoxy functional group on the coumarin skeleton, had the notable antimicrobial activity against foodborne pathogens. However, 7-hydroxycoumarin and 6,7-dihydroxycoumarin, which contained a hydroxyl functional group on the coumarin skeleton, had no antimicrobial activity against these pathogens. An increase in cell membrane permeability was confirmed by electron microscopy observations, and release of extracellular ATP and cell constituents followed treatment with the ethyl acetate fraction of F. rhynchophylla extract. These findings indicate that F. rhynchophylla extract and coumarin analogues have potential for use as antimicrobial agents against foodborne pathogens and that the antimicrobial mechanisms are associated with the loss of cell membrane integrity.

  8. Comparative study of the mechanical properties from different polycarbonates

    International Nuclear Information System (INIS)

    Terence, M.C.; Miranda, A.; Guedes, S.M.L.; Sciani, V.

    1995-01-01

    The polycarbonates (PC) with molecular weight 22000 and 27000 g/mol fabricated by Policarbonatos do Brasil S.A., as irradiated by γ rays with doses between 0 and 300 kGy in presence of air at room temperature. The effects in the mechanical properties of PC were investigated using an INSTRON dynamometer. The results showed that both PC have good mechanical stability. (author). 6 refs, 2 figs

  9. Mechanical Properties of Spray Cast 7XXX Series Aluminium Alloys

    OpenAIRE

    SALAMCI, Elmas

    2014-01-01

    Mechanical properties of spray deposited and extruded 7xxx series aluminium alloys were investigated in peak aged condition. To study the influence of Zn additions on the mechanical behaviour of spray deposited materials, three alloy compositions were selected, namely: SS70 (11.5% Zn), N707 (10.9% Zn) and 7075 (5.6% Zn). After ageing treatment, notched and unnotched specimens of spray deposited alloys were subjected to tensile tests at room temperature. Experimental results showed...

  10. Permeability enhancement by shock cooling

    Science.gov (United States)

    Griffiths, Luke; Heap, Michael; Reuschlé, Thierry; Baud, Patrick; Schmittbuhl, Jean

    2015-04-01

    The permeability of an efficient reservoir, e.g. a geothermal reservoir, should be sufficient to permit the circulation of fluids. Generally speaking, permeability decreases over the life cycle of the geothermal system. As a result, is usually necessary to artificially maintain and enhance the natural permeability of these systems. One of the methods of enhancement -- studied here -- is thermal stimulation (injecting cold water at low pressure). This goal of this method is to encourage new thermal cracks within the reservoir host rocks, thereby increasing reservoir permeability. To investigate the development of thermal microcracking in the laboratory we selected two granites: a fine-grained (Garibaldi Grey granite, grain size = 0.5 mm) and a course-grained granite (Lanhelin granite, grain size = 2 mm). Both granites have an initial porosity of about 1%. Our samples were heated to a range of temperatures (100-1000 °C) and were either cooled slowly (1 °C/min) or shock cooled (100 °C/s). A systematic microstructural (2D crack area density, using standard stereological techniques, and 3D BET specific surface area measurements) and rock physical property (porosity, P-wave velocity, uniaxial compressive strength, and permeability) analysis was undertaken to understand the influence of slow and shock cooling on our reservoir granites. Microstructurally, we observe that the 2D crack surface area per unit volume and the specific surface area increase as a result of thermal stressing, and, for the same maximum temperature, crack surface area is higher in the shock cooled samples. This observation is echoed by our rock physical property measurements: we see greater changes for the shock cooled samples. We can conclude that shock cooling is an extremely efficient method of generating thermal microcracks and modifying rock physical properties. Our study highlights that thermal treatments are likely to be an efficient method for the "matrix" permeability enhancement of

  11. Exploration of mechanisms underlying the strain-rate-dependent mechanical property of single chondrocytes

    Energy Technology Data Exchange (ETDEWEB)

    Nguyen, Trung Dung; Gu, YuanTong, E-mail: yuantong.gu@qut.edu.au [School of Chemistry, Physics and Mechanical Engineering, Queensland University of Technology, Brisbane, Queensland (Australia)

    2014-05-05

    Based on the characterization by Atomic Force Microscopy, we report that the mechanical property of single chondrocytes has dependency on the strain-rates. By comparing the mechanical deformation responses and the Young's moduli of living and fixed chondrocytes at four different strain-rates, we explore the deformation mechanisms underlying this dependency property. We found that the strain-rate-dependent mechanical property of living cells is governed by both of the cellular cytoskeleton and the intracellular fluid when the fixed chondrocytes are mainly governed by their intracellular fluid, which is called the consolidation-dependent deformation behavior. Finally, we report that the porohyperelastic constitutive material model which can capture the consolidation-dependent behavior of both living and fixed chondrocytes is a potential candidature to study living cell biomechanics.

  12. Mechanical property estimation with ABI and FEM simulation

    International Nuclear Information System (INIS)

    Sharma, Kamal; Singh, P.K.; Das, Gautam; Bhasin, Vivek; Vaze, K.K.; Ghosh, A.K.

    2007-01-01

    A combined mechanical property evaluation methodology with ABI (Automated Ball Indentation) simulation and Artificial Neural Network (ANN) analysis is evolved to evaluate the mechanical properties for material. The experimental load deflection data is converted into meaningful mechanical properties for this material. An ANN database is generated with the help of contact type finite element analysis by numerically simulating the ABI process for various magnitudes of yield strength (σ yp ) (200 MPa - 500 MPa) with a range of strain hardening exponent (n) (0.1 - 0.5) and strength coefficient (K) (500 MPa - 1500 MPa). For the present problem, a ball indenter of 1.57 mm diameter having Young's modulus approximately 100 times more than the test piece is used to minimize the error due to indenter deformation. Test piece dimension is kept large enough in comparison to the indenter configuration in the simulation to minimize the deflection at the outer edge of the test piece. Further this database after the neural network training; is used to analyze measured material properties of different test pieces. The ANN predictions are reconfirmed with contact type finite element analysis for an arbitrary selected test sample. The methodology evolved in this work can be extended to predict material properties for any irradiated nuclear material in the service. (author)

  13. Influence of wood defects on some mechanical properties of two ...

    African Journals Online (AJOL)

    Effects of slope of wood grain, knot, split, ingrowth and sapwood on some mechanical wood properties of Pterygota macrocarpa (Kyere) and Piptadeniastrum africanum (Dahoma) have been studied, using structural size specimens and a 60 tonne structural wood testing machine. The study on the two tropical hardwoods ...

  14. Effects of moisture on the mechanical properties of glass fibre ...

    Indian Academy of Sciences (India)

    Unknown

    of moisture absorption and correlating with the mechanical properties, it was observed that the ..... where F is the flux of moisture molecules crossing a unit ... 300. 400. 500. 600. 700 wt% of nascent fibre loading. 63.50. 55.75. 48.48. 38.63.

  15. Effect of carbon nanofibre addition on the mechanical properties of ...

    Indian Academy of Sciences (India)

    Owing to the good mechanical properties of the carbon nanofibres (CNFs), they ... 8H Satin, T-300 carbon fabric (C-fabric) was used as rein- forcement. ... below. Absolute strength (S) in MPa at a given Vf: S = a + bVf + cV 2 f , where 'a' is the ...

  16. Mechanical Properties of Potato- Starch Linear Low Density ...

    African Journals Online (AJOL)

    The mechanical properties of potato-starch filled LLDPE such as Young's Modulus, tensile strength and elongation at break were studied. Apart from the Young's Modulus, the tensile strength and elongation at break reduced with increased starch content. This is attributed to poor adhesion between starch and the polymer ...

  17. Influence of tempering temperature on mechanical properties of cast steels

    Directory of Open Access Journals (Sweden)

    G. Golański

    2008-12-01

    Full Text Available The paper presents results of research on the influence of tempering temperature on structure and mechanical properties of bainite hardened cast steel: G21CrMoV4 – 6 (L21HMF and G17CrMoV5 – 10 (L17HMF. Investigated cast steels were taken out from internal frames of steam turbines serviced for long time at elevated temperatures. Tempering of the investigated cast steel was carried out within the temperature range of 690 ÷ 730 C (G21CrMoV4 – 6 and 700 ÷ 740 C (G17CrMoV5 – 10. After tempering the cast steels were characterized by a structure of tempered lower bainite with numerous precipitations of carbides. Performed research of mechanical properties has shown that high temperatures of tempering of bainitic structure do not cause decrease of mechanical properties beneath the required minimum.oo It has also been proved that high-temperature tempering (>720 oC ensures high impact energy at the 20% decrease of mechanical properties.

  18. Comparative study of some mechanical and release properties of ...

    African Journals Online (AJOL)

    The mechanical and release properties of paracetamol tablets formulated with cashew gum (CAG), povidone (PVP) and gelatin (GEL) as binders were studied and compared. The parameters studied were tensile strength (TS), brittle fracture index (BFI), friability (F), disintegration time (DT) and percentage drug released ...

  19. IMPACT OF OIL ON THE MECHANICAL PROPERTIES OF SOIL SUBSIDENCE

    Directory of Open Access Journals (Sweden)

    Алексей Алексеевич Бурцев

    2016-08-01

    Full Text Available The paper studied the effect of oil content on the mechanical properties of soil subsidence - Ek modulus and compressibility factor m0, obtained in the laboratory with the help of artificial impregnation oil soil samples. A comparison of the above parameters with samples of the same soil in the natural and water-saturated conditions has been perfomed.

  20. Comparison of mechanical properties for several electrical spring contact alloys

    International Nuclear Information System (INIS)

    Nordstrom, T.V.

    1976-06-01

    Work was conducted to determine whether beryllium-nickel alloy 440 had mechanical properties which made it suitable as a substitute for the presently used precious metal contact alloys Paliney 7 and Neyoro G, in certain electrical contact applications. Possible areas of applicability for the alloy were where extremely low contact resistance was not necessary or in components encountering elevated temperatures above those presently seen in weapons applications. Evaluation of the alloy involved three major experimental areas: 1) measurement of the room temperature microplastic (epsilon approximately 10 -6 ) and macroplastic (epsilon approximately 10 -3 ) behavior of alloy 440 in various age hardening conditions, 2) determination of applied stress effects on stress relaxation or contact force loss and 3) measurement of elevated temperature mechanical properties and stress relaxation behavior. Similar measurements were also made on Neyoro G and Paliney 7 for comparison. The primary results of the study show that beryllium-nickel alloy 440 is from a mechanical properties standpoint, equal or superior to the presently used Paliney 7 and Neyoro G for normal Sandia requirements. For elevated temperature applications, alloy 440 has clearly superior mechanical properties

  1. Structural characterization and mechanical properties of polypropylene reinforced natural fibers

    Science.gov (United States)

    Karim, M. A. A.; Zaman, I.; Rozlan, S. A. M.; Berhanuddin, N. I. C.; Manshoor, B.; Mustapha, M. S.; Khalid, A.; Chan, S. W.

    2017-10-01

    Recently the development of natural fiber composite instead of synthetics fiber has lead to eco-friendly product manufacturing to meet various applications in the field of automotive, construction and manufacturing. The use of natural fibers offer an alternative to the reinforcing fibers because of their good mechanical properties, low density, renewability, and biodegradability. In this present research, the effects of maleic anhydride polypropylene (MAPP) on the mechanical properties and material characterization behaviour of kenaf fiber and coir fiber reinforced polypropylene were investigated. Different fractions of composites with 10wt%, 20wt% and 30wt% fiber content were prepared by using brabender mixer at 190°C. The 3wt% MAPP was added during the mixing. The composites were subsequently molded with injection molding to prepare the test specimens. The mechanical properties of the samples were investigated according to ISO 527 to determine the tensile strength and modulus. These results were also confirmed by the SEM machine observations of fracture surface of composites and FTIR analysis of the chemical structure. As the results, the presence of MAPP helps increasing the mechanical properties of both fibers and 30wt% kenaf fiber with 3wt% MAPP gives the best result compare to others.

  2. Uniaxial and biaxial mechanical properties of porcine linea alba

    NARCIS (Netherlands)

    Cooney, Gerard M.; Moerman, Kevin M.; Takaza, Michael; Winter, Des C.; Simms, Ciaran K.

    2015-01-01

    Incisional hernia is a severe complication post-laparoscopic/laparotomy surgery that is commonly associated with the linea alba. However, the few studies on the mechanical properties of the linea alba in the literature appear contradictory, possible due to challenges with the physical dimensions of

  3. Sterilizing elastomeric chains without losing mechanical properties. Is it possible?

    Directory of Open Access Journals (Sweden)

    Matheus Melo Pithon

    2015-06-01

    Full Text Available OBJECTIVE: To investigate the effects of different sterilization/disinfection methods on the mechanical properties of orthodontic elastomeric chains. METHODS: Segments of elastomeric chains with 5 links each were sent for sterilization by cobalt 60 (Co60 (20 KGy gamma ray technology. After the procedure, the elastomeric chains were contaminated with clinical samples of Streptococcus mutans. Subsequently, the elastomeric chains were submitted to sterilization/disinfection tests carried out by means of different methods, forming six study groups, as follows: Group 1 (control - without contamination, Group 2 (70°GL alcohol, Group 3 (autoclave, Group 4 (ultraviolet, Group 5 (peracetic acid and Group 6 (glutaraldehyde. After sterilization/disinfection, the effectiveness of these methods, by Colony forming units per mL (CFU/mL, and the mechanical properties of the material were assessed. Student's t-test was used to assess the number of CFUs while ANOVA and Tukey's test were used to assess elastic strength. RESULTS: Ultraviolet treatment was not completely effective for sterilization. No loss of mechanical properties occurred with the use of the different sterilization methods (p > 0.05. CONCLUSION: Biological control of elastomeric chains does not affect their mechanical properties.

  4. Microstructure and mechanical properties of SiC materials

    International Nuclear Information System (INIS)

    Yarahmadi, M.

    1985-01-01

    The effect of the microstructure on the mechanical properties of SiC materials of different chemical composition (SSiC, SiSiC, and RSiC) was investigated. Furthermore, the creep strength was determined on oxidized samples and on non-pretreated samples. (HSCH)

  5. Microstructure and mechanical properties of Mg–HAP composites

    Indian Academy of Sciences (India)

    Administrator

    tion of load bearing capacity and suitable mechanical and metallurgical properties. ... lity as compared to β-TCP in our body fluid (Kwon et al. 2003). The HAP ... steel crucible under the protection of gas mixture contain- ing SF6 and CO2.

  6. Bone Quality: The Mechanical Effects of Microarchitecture and Matrix Properties

    NARCIS (Netherlands)

    J.S. Day (Judd)

    2005-01-01

    textabstractIn this body of work we have examined some of the current concepts pertaining to the relation between bone mass, bone quality and the mechanical properties of bone. In our first series of studies we used a model of human osteoarthritis to investigate the implications of changes in the

  7. The Effects of Moisture Content on Mechanical Properties of Soybean

    African Journals Online (AJOL)

    Some mechanical properties were determined for four varieties of soybean (TGX 297-129C, Samsoy1, TGX 306-636C and TGX 536-02D). The hardness, compressive and tensile strength determination were carried out using a Rockwell Hardness machine and tensometer. The effect of moisture content on the hardness ...

  8. a comparative study of the physical and mechanical properties

    African Journals Online (AJOL)

    HP-User

    [11] British Standard Institutes, BS EN 1097-6:2000, Tests for mechanical and physical properties of aggregates. Determination of particle density and water absorption, British Standard Institution, London. [12] Adaba, C. S., Agunwamba, J. C., Nwoji, C. U., Onya, O. E.,. Oze, S, “Comparative Cost And Strength Analysis Of.

  9. PHYSICAL AND MECHANICAL PROPERTIES OF JUVENILE Schizolobium amazonicum WOOD

    Directory of Open Access Journals (Sweden)

    Graziela Baptista Vidaurre

    2018-03-01

    Full Text Available ABSTRACT Growth in world demand for wood implies a search for new fast growing species with silvicultural potential, and in this scenario for native species such as Paricá . Thus, the objective of this study was determining the physical and mechanical wood properties of the Schizolobium amazonicum species (known as Paricá in Brazil. Trees were collected from commercial plantations located in the north of Brazil with ages of 5, 7, 9 and 11 years. Four logs from trees of each age in the longitudinal direction of the trees were obtained, and later a diametrical plank of each log was taken to manufacture the specimens which were used to evaluate some physical and mechanical properties of the wood. The basic density of Paricá was reduced in the basetop direction and no difference between the radial positions was observed, while the average basic density of this wood was characterized as low. The region close to the bark showed less longitudinal contraction and also greater homogeneity of this property along the trunk, while for tangential contraction the smallest variation was found in the region near the pith. Paricá wood contraction was characterized as low. Age influenced most of the mechanical properties, where logs from the base had the highest values of mechanical strength.

  10. ODS steel fabrication: relationships between process, microstructure and mechanical properties

    International Nuclear Information System (INIS)

    Couvrat, M.

    2011-01-01

    Oxide Dispersion Strengthened (ODS) steels are promising candidate materials for generation IV and fusion nuclear energy systems thanks to their excellent thermal stability, high-temperature creep strength and good irradiation resistance. Their superior properties are attributed both to their nano-structured matrix and to a high density of Y-Ti-O nano-scale clusters (NCs). ODS steels are generally prepared by Mechanical Alloying of a pre-alloyed Fe-Cr-W-Ti powder with Y 2 O 3 powder. A fully dense bar or tube is then produced from this nano-structured powder by the mean of hot extrusion. The aim of this work was to determine the main parameters of the process of hot extrusion and to understand the link between the fabrication process, the microstructure and the mechanical properties. The material microstructure was characterized at each step of the process and bars were extruded with varying hot extrusion parameters so as to identify the impact of these parameters. Temperature then appeared to be the main parameter having a great impact on microstructure and mechanical properties of the extruded material. We then proposed a cartography giving the microstructure versus the process parameters. Based on these results, it is possible to control very accurately the obtained material microstructure and mechanical properties setting the extrusion parameters. (author) [fr

  11. Mechanical properties of very thin cover slip glass disk

    Indian Academy of Sciences (India)

    Unknown

    Mechanical properties of very thin cover slip glass disk. A SEAL, A K DALUI, M BANERJEE, A K MUKHOPADHYAY* and K K PHANI. Central Glass and Ceramic Research Institute, Kolkata 700 032, India. Abstract. The biaxial flexural strength, Young's modulus, Vicker's microhardness and fracture toughness data for very ...

  12. Effect of surfactants on the mechanical properties of acetaminophen ...

    African Journals Online (AJOL)

    The purpose of this study was to investigate the effect of non ionic surfactant on the mechanical properties of acetaminophen-wax matrix tablet and hence its implication on dissolution profile. Acetaminophen-wax matrix granules were prepared by melt granulation technique. This was formed by triturating acetaminophen ...

  13. Investigation of the mechanical and physical properties of greywacke specimens

    Czech Academy of Sciences Publication Activity Database

    Holub, Karel; Konečný, Pavel; Knejzlík, Jaromír

    2009-01-01

    Roč. 46, č. 1 (2009), s. 188-193 ISSN 1365-1609 Institutional research plan: CEZ:AV0Z30860518 Keywords : greywacke * mechanical and physical properties Subject RIV: DC - Siesmology, Volcanology, Earth Structure Impact factor: 1.142, year: 2009 www.elsevier.com/locate ijrmms

  14. Microstructures and mechanical properties of Mg–Zn–Zr–Dy ...

    Indian Academy of Sciences (India)

    Microstructures and phase compositions of as-cast and extruded ZK60–Dy ( = 0–5) alloys were analysed by optical microscope, scanning electron microscope, X-ray diffraction and differential scanning calorimetry. Meanwhile, the tensile mechanical property was tested.With increasing Dy content, Mg–Zn–Dy new phase ...

  15. Mechanical Properties of High Performance Cementitious Grout (II)

    DEFF Research Database (Denmark)

    Sørensen, Eigil V.

    The present report is an update of the report “Mechanical Properties of High Performance Cementitious Grout (I)” [1] and describes tests carried out on the high performance grout MASTERFLOW 9500, marked “WMG 7145 FP”, developed by BASF Construction Chemicals A/S and designed for use in grouted...

  16. Mechanical properties of concrete for power reactor at high temperatures

    International Nuclear Information System (INIS)

    Kawase, Kiyotaka; Tanaka, Hitoshi; Nakano, Masayuki

    1985-01-01

    The purpose of this study is to investigate the mechanical properties of concrete for power reactor at high temperature. This paper presents the creep behavior of concrete at high temperature and the cause by which a specified aggregate is broken at a specified high temperature. The creep coefficient at high temperature is smaller than that at ordinary temperature. (author)

  17. The durability and mechanical strenght properties of bamboo in ...

    African Journals Online (AJOL)

    The durability and mechanical strenght properties of bamboo in reinforced concrete. GA Alade, FA Olutoge, AA Alade. Abstract. No Abstract. Journal of Applied Science, Engineering and Technology Vol. 4(2) 2004: 35-40. Full Text: EMAIL FULL TEXT EMAIL FULL TEXT · DOWNLOAD FULL TEXT DOWNLOAD FULL TEXT.

  18. Crystallization and mechanical properties of biodegradable poly(p ...

    Indian Academy of Sciences (India)

    Effect of ome-POSS on the isothermal melt crystallization and dynamic mechanical properties of PPDO in the ... attracting more and more attention in recent times.12–14 Blen- ..... spent at Ts is enough to erase the crystalline memory of the.

  19. Investigation of the physical and mechanical properties of Shea Tree ...

    African Journals Online (AJOL)

    Investigation of the physical and mechanical properties of Shea Tree timber ( Vitellaria paradoxa ) used for structural applications in Kwara State, Nigeria. ... strength parallel to grain of 24.7 (N/mm2), compressive strength perpendicular to grain of 8.99 (N/mm2), shear strength of 2.01 (N/mm2), and tensile strength parallel to ...

  20. effects of sulphur addition on addition on and mechanical properties

    African Journals Online (AJOL)

    User

    on the microstructure and mechanical properties of sand cast been investigated ... owed that the addition of sulphur to Al-12wt%Si alloy. 12wt%Si alloy .... 28 materials. 29. Element. Aluminum. Silicon. Al. Si. Ca. Fe. Cu. Zn. Mn. Mg. Cr. B. 99.71.

  1. Could humicity affect the mechanical properties of carbon based coatings?

    Czech Academy of Sciences Publication Activity Database

    Sobota, Jaroslav; Grossman, Jan; Vyskočil, J.; Novák, R.; Fořt, Tomáš; Vítů, T.; Dupák, Libor

    2010-01-01

    Roč. 104, č. 15 (2010), s. 375-377 ISSN 0009-2770 Institutional research plan: CEZ:AV0Z20650511 Keywords : carbon * mechanical properties * humidity * fracture toughness of hard thin coatings Subject RIV: JI - Composite Materials Impact factor: 0.620, year: 2010

  2. Evaluation of the mechanical and physical properties of a posterior ...

    African Journals Online (AJOL)

    To evaluate the mechanical and physical properties of a micro-hybrid resin composite used in adult posterior restorations A micro-hybrid, light curing resin composite Unolux BCS Composite Restorative, (UnoDent, England) was used to restore 74 carious classes I and II cavities on posterior teeth of 62 adult patients.

  3. Mechanical properties of hyaline and repair cartilage studied by nanoindentation.

    Science.gov (United States)

    Franke, O; Durst, K; Maier, V; Göken, M; Birkholz, T; Schneider, H; Hennig, F; Gelse, K

    2007-11-01

    Articular cartilage is a highly organized tissue that is well adapted to the functional demands in joints but difficult to replicate via tissue engineering or regeneration. Its viscoelastic properties allow cartilage to adapt to both slow and rapid mechanical loading. Several cartilage repair strategies that aim to restore tissue and protect it from further degeneration have been introduced. The key to their success is the quality of the newly formed tissue. In this study, periosteal cells loaded on a scaffold were used to repair large partial-thickness cartilage defects in the knee joint of miniature pigs. The repair cartilage was analyzed 26 weeks after surgery and compared both morphologically and mechanically with healthy hyaline cartilage. Contact stiffness, reduced modulus and hardness as key mechanical properties were examined in vitro by nanoindentation in phosphate-buffered saline at room temperature. In addition, the influence of tissue fixation with paraformaldehyde on the biomechanical properties was investigated. Although the repair process resulted in the formation of a stable fibrocartilaginous tissue, its contact stiffness was lower than that of hyaline cartilage by a factor of 10. Fixation with paraformaldehyde significantly increased the stiffness of cartilaginous tissue by one order of magnitude, and therefore, should not be used when studying biomechanical properties of cartilage. Our study suggests a sensitive method for measuring the contact stiffness of articular cartilage and demonstrates the importance of mechanical analysis for proper evaluation of the success of cartilage repair strategies.

  4. Mechanical properties of ceramic structures based on Triply Periodic Minimal Surface (TPMS) processed by 3D printing

    Science.gov (United States)

    Restrepo, S.; Ocampo, S.; Ramírez, J. A.; Paucar, C.; García, C.

    2017-12-01

    Repairing tissues and organs has been the main goal of surgical procedures. Since the 1990s, the main goal of tissue engineering has been reparation, using porous scaffolds that serve as a three-dimensional template for the initial fixation of cells and subsequent tissue formation both in vitro and in vivo. A scaffold must have specific characteristics of porosity, interconnectivity, surface area, pore volume, surface tortuosity, permeability and mechanical properties, which makes its design, manufacturing and characterization a complex process. Inspired by nature, triply periodic minimal surfaces (TPMS) have emerged as an alternative for the manufacture of porous pieces with design requirements, such as scaffolds for tissue repair. In the present work, we used the technique of 3D printing to obtain ceramic structures with Gyroid, Schwarz Primitive and Schwarz Diamond Surfaces shapes, three TPMS that fulfil the geometric requirements of a bone tissue scaffold. The main objective of this work is to compare the mechanical properties of ceramic pieces of three different forms of TPMS printed in 3D using a commercial ceramic paste. In this way it will be possible to clarify which is the TPMS with appropriate characteristics to construct scaffolds of ceramic materials for bone repair. A dependence of the mechanical properties with the geometry was found being the Primitive Surface which shows the highest mechanical properties.

  5. Self-Healing Capability of Fiber-Reinforced Cementitious Composites for Recovery of Watertightness and Mechanical Properties

    Directory of Open Access Journals (Sweden)

    Tomoya Nishiwaki

    2014-03-01

    Full Text Available Various types of fiber reinforced cementitious composites (FRCCs were experimentally studied to evaluate their self-healing capabilities regarding their watertightness and mechanical properties. Cracks were induced in the FRCC specimens during a tensile loading test, and the specimens were then immersed in static water for self-healing. By water permeability and reloading tests, it was determined that the FRCCs containing synthetic fiber and cracks of width within a certain range (<0.1 mm exhibited good self-healing capabilities regarding their watertightness. Particularly, the high polarity of the synthetic fiber (polyvinyl alcohol (PVA series and hybrid fiber reinforcing (polyethylene (PE and steel code (SC series showed high recovery ratio. Moreover, these series also showed high potential of self-healing of mechanical properties. It was confirmed that recovery of mechanical property could be obtained only in case when crack width was sufficiently narrow, both the visible surface cracks and the very fine cracks around the bridging of the SC fibers. Recovery of the bond strength by filling of the very fine cracks around the bridging fibers enhanced the recovery of the mechanical property.

  6. Investigation clogging dynamic of permeable pavement systems using embedded sensors

    Science.gov (United States)

    Permeable pavement is a stormwater control measure commonly selected in both new and retrofit applications. However, there is limited information about the clogging mechanism of these systems that effects the infiltration. A permeable pavement site located at the Seitz Elementary...

  7. Determining the Mechanical Properties of Lattice Block Structures

    Science.gov (United States)

    Wilmoth, Nathan

    2013-01-01

    Lattice block structures and shape memory alloys possess several traits ideal for solving intriguing new engineering problems in industries such as aerospace, military, and transportation. Recent testing at the NASA Glenn Research Center has investigated the material properties of lattice block structures cast from a conventional aerospace titanium alloy as well as lattice block structures cast from nickel-titanium shape memory alloy. The lattice block structures for both materials were sectioned into smaller subelements for tension and compression testing. The results from the cast conventional titanium material showed that the expected mechanical properties were maintained. The shape memory alloy material was found to be extremely brittle from the casting process and only compression testing was completed. Future shape memory alloy lattice block structures will utilize an adjusted material composition that will provide a better quality casting. The testing effort resulted in baseline mechanical property data from the conventional titanium material for comparison to shape memory alloy materials once suitable castings are available.

  8. Porcine bladder acellular matrix (ACM): protein expression, mechanical properties

    Energy Technology Data Exchange (ETDEWEB)

    Farhat, Walid A [Department of Surgery, Division of Urology, University of Toronto and Hospital for Sick Children, Toronto, ON M5G 1X8 (Canada); Chen Jun; Haig, Jennifer; Antoon, Roula; Litman, Jessica; Yeger, Herman [Department of Developmental and Stem Cell Biology, Research Institute, Hospital for Sick Children, Toronto, ON M5G 1X8 (Canada); Sherman, Christopher [Department of Anatomic Pathology, Sunnybrook and Women' s College Health Sciences Centre, Toronto, ON (Canada); Derwin, Kathleen [Department of Biomedical Engineering, Lerner Research Institute and Orthopaedic Research Center, Cleveland Clinic Foundation, Cleveland, OH (United States)], E-mail: walid.farhat@sickkids.ca

    2008-06-01

    Experimentally, porcine bladder acellular matrix (ACM) that mimics extracellular matrix has excellent potential as a bladder substitute. Herein we investigated the spatial localization and expression of different key cellular and extracellular proteins in the ACM; furthermore, we evaluated the inherent mechanical properties of the resultant ACM prior to implantation. Using a proprietary decellularization method, the DNA contents in both ACM and normal bladder were measured; in addition we used immunohistochemistry and western blots to quantify and localize the different cellular and extracellular components, and finally the mechanical testing was performed using a uniaxial mechanical testing machine. The mean DNA content in the ACM was significantly lower in the ACM compared to the bladder. Furthermore, the immunohistochemical and western blot analyses showed that collagen I and IV were preserved in the ACM, but possibly denatured collagen III in the ACM. Furthermore, elastin, laminin and fibronectin were mildly reduced in the ACM. Although the ACM did not exhibit nucleated cells, residual cellular components (actin, myosin, vimentin and others) were still present. There was, on the other hand, no significant difference in the mean stiffness between the ACM and the bladder. Although our decellularization method is effective in removing nuclear material from the bladder while maintaining its inherent mechanical properties, further work is mandatory to determine whether these residual DNA and cellular remnants would lead to any immune reaction, or if the mechanical properties of the ACM are preserved upon implantation and cellularization.

  9. Porcine bladder acellular matrix (ACM): protein expression, mechanical properties

    International Nuclear Information System (INIS)

    Farhat, Walid A; Chen Jun; Haig, Jennifer; Antoon, Roula; Litman, Jessica; Yeger, Herman; Sherman, Christopher; Derwin, Kathleen

    2008-01-01

    Experimentally, porcine bladder acellular matrix (ACM) that mimics extracellular matrix has excellent potential as a bladder substitute. Herein we investigated the spatial localization and expression of different key cellular and extracellular proteins in the ACM; furthermore, we evaluated the inherent mechanical properties of the resultant ACM prior to implantation. Using a proprietary decellularization method, the DNA contents in both ACM and normal bladder were measured; in addition we used immunohistochemistry and western blots to quantify and localize the different cellular and extracellular components, and finally the mechanical testing was performed using a uniaxial mechanical testing machine. The mean DNA content in the ACM was significantly lower in the ACM compared to the bladder. Furthermore, the immunohistochemical and western blot analyses showed that collagen I and IV were preserved in the ACM, but possibly denatured collagen III in the ACM. Furthermore, elastin, laminin and fibronectin were mildly reduced in the ACM. Although the ACM did not exhibit nucleated cells, residual cellular components (actin, myosin, vimentin and others) were still present. There was, on the other hand, no significant difference in the mean stiffness between the ACM and the bladder. Although our decellularization method is effective in removing nuclear material from the bladder while maintaining its inherent mechanical properties, further work is mandatory to determine whether these residual DNA and cellular remnants would lead to any immune reaction, or if the mechanical properties of the ACM are preserved upon implantation and cellularization

  10. Porcine bladder acellular matrix (ACM): protein expression, mechanical properties.

    Science.gov (United States)

    Farhat, Walid A; Chen, Jun; Haig, Jennifer; Antoon, Roula; Litman, Jessica; Sherman, Christopher; Derwin, Kathleen; Yeger, Herman

    2008-06-01

    Experimentally, porcine bladder acellular matrix (ACM) that mimics extracellular matrix has excellent potential as a bladder substitute. Herein we investigated the spatial localization and expression of different key cellular and extracellular proteins in the ACM; furthermore, we evaluated the inherent mechanical properties of the resultant ACM prior to implantation. Using a proprietary decellularization method, the DNA contents in both ACM and normal bladder were measured; in addition we used immunohistochemistry and western blots to quantify and localize the different cellular and extracellular components, and finally the mechanical testing was performed using a uniaxial mechanical testing machine. The mean DNA content in the ACM was significantly lower in the ACM compared to the bladder. Furthermore, the immunohistochemical and western blot analyses showed that collagen I and IV were preserved in the ACM, but possibly denatured collagen III in the ACM. Furthermore, elastin, laminin and fibronectin were mildly reduced in the ACM. Although the ACM did not exhibit nucleated cells, residual cellular components (actin, myosin, vimentin and others) were still present. There was, on the other hand, no significant difference in the mean stiffness between the ACM and the bladder. Although our decellularization method is effective in removing nuclear material from the bladder while maintaining its inherent mechanical properties, further work is mandatory to determine whether these residual DNA and cellular remnants would lead to any immune reaction, or if the mechanical properties of the ACM are preserved upon implantation and cellularization.

  11. Mechanical properties of canine osteosarcoma-affected antebrachia.

    Science.gov (United States)

    Steffey, Michele A; Garcia, Tanya C; Daniel, Leticia; Zwingenberger, Allison L; Stover, Susan M

    2017-05-01

    To determine the influence of neoplasia on the biomechanical properties of canine antebrachia. Ex vivo biomechanical study. Osteosarcoma (OSA)-affected canine antebrachia (n = 12) and unaffected canine antebrachia (n = 9). Antebrachia were compressed in axial loading until failure. A load-deformation curve was used to acquire the structural mechanical properties of neoplastic and unaffected specimens. Structural properties and properties normalized by body weight (BW) and radius length were compared using analysis of variance (ANOVA). Modes of failure were compared descriptively. Neoplastic antebrachia fractured at, or adjacent to, the OSA in the distal radial diaphysis. Unaffected antebrachia failed via mid-diaphyseal radial fractures with a transverse cranial component and an oblique caudal component. Structural mechanical properties were more variable in neoplastic antebrachia than unaffected antebrachia, which was partially attributable to differences in bone geometry related to dog size. When normalized by dog BW and radial length, strength, stiffness, and energy to yield and failure, were lower in neoplastic antebrachia than in unaffected antebrachia. OSA of the distal radial metaphysis in dogs presented for limb amputation markedly compromises the structural integrity of affected antebrachia. However, biomechanical properties of affected bones was sufficient for weight-bearing, as none of the neoplastic antebrachia fractured before amputation. The behavior of tumor invaded bone under cyclic loading warrants further investigations to evaluate the viability of in situ therapies for bone tumors in dogs. © 2017 The American College of Veterinary Surgeons.

  12. Clogging in permeable concrete: A review.

    Science.gov (United States)

    Kia, Alalea; Wong, Hong S; Cheeseman, Christopher R

    2017-05-15

    Permeable concrete (or "pervious concrete" in North America) is used to reduce local flooding in urban areas and is an important sustainable urban drainage system. However, permeable concrete exhibits reduction in permeability due to clogging by particulates, which severely limits service life. This paper reviews the clogging mechanism and current mitigating strategies in order to inform future research needs. The pore structure of permeable concrete and characteristics of flowing particulates influence clogging, which occurs when particles build-up and block connected porosity. Permeable concrete requires regular maintenance by vacuum sweeping and pressure washing, but the effectiveness and viability of these methods is questionable. The potential for clogging is related to the tortuosity of the connected porosity, with greater tortuosity resulting in increased potential for clogging. Research is required to develop permeable concrete that can be poured on-site, which produces a pore structure with significantly reduced tortuosity. Copyright © 2017 Elsevier Ltd. All rights reserved.

  13. Optimization of mechanical properties, biocorrosion properties and antibacterial properties of wrought Ti-3Cu alloy by heat treatment

    Directory of Open Access Journals (Sweden)

    Mianmian Bao

    2018-03-01

    Full Text Available Previous study has shown that Ti-3Cu alloy shows good antibacterial properties (>90% antibacterial rate, but the mechanical properties still need to be improved. In this paper, a series of heat-treatment processes were selected to adjust the microstructure in order to optimize the properties of Ti-3Cu alloy. Microstructure, mechanical properties, biocorrosion properties and antibacterial properties of wrought Ti-3Cu alloy at different conditions was systematically investigated by X-ray diffraction, optical microscope, scanning electron microscope, transmission electron microscopy, electrochemical measurements, tensile test, fatigue test and antibacterial test. Heat treatment could significantly improve the mechanical properties, corrosion resistance and antibacterial rate due to the redistribution of copper elements and precipitation of Ti2Cu phase. Solid solution treatment increased the yield strength from 400 to 740 MPa and improved the antibacterial rate from 33% to 65.2% while aging treatment enhanced the yield strength to 800–850 MPa and antibacterial rate (>91.32%. It was demonstrated that homogeneous distribution and fine Ti2Cu phase plays a very important role in mechanical properties, corrosion resistance and antibacterial properties.

  14. Optimization of mechanical properties, biocorrosion properties and antibacterial properties of wrought Ti-3Cu alloy by heat treatment.

    Science.gov (United States)

    Bao, Mianmian; Liu, Ying; Wang, Xiaoyan; Yang, Lei; Li, Shengyi; Ren, Jing; Qin, Gaowu; Zhang, Erlin

    2018-03-01

    Previous study has shown that Ti-3Cu alloy shows good antibacterial properties (>90% antibacterial rate), but the mechanical properties still need to be improved. In this paper, a series of heat-treatment processes were selected to adjust the microstructure in order to optimize the properties of Ti-3Cu alloy. Microstructure, mechanical properties, biocorrosion properties and antibacterial properties of wrought Ti-3Cu alloy at different conditions was systematically investigated by X-ray diffraction, optical microscope, scanning electron microscope, transmission electron microscopy, electrochemical measurements, tensile test, fatigue test and antibacterial test. Heat treatment could significantly improve the mechanical properties, corrosion resistance and antibacterial rate due to the redistribution of copper elements and precipitation of Ti 2 Cu phase. Solid solution treatment increased the yield strength from 400 to 740 MPa and improved the antibacterial rate from 33% to 65.2% while aging treatment enhanced the yield strength to 800-850 MPa and antibacterial rate (>91.32%). It was demonstrated that homogeneous distribution and fine Ti 2 Cu phase plays a very important role in mechanical properties, corrosion resistance and antibacterial properties.

  15. Modeling of mechanical properties in alpha/beta-titanium alloys

    Science.gov (United States)

    Kar, Sujoy Kumar

    2005-11-01

    The accelerated insertion of titanium alloys in component application requires the development of predictive capabilities for various aspects of their behavior, for example, phase stability, microstructural evolution and property-microstructure relationships over a wide range of length and time scales. In this presentation some navel aspects of property-microstructure relationships and microstructural evolution in alpha/beta Ti alloys will be discussed. Neural Network (NN) Models based on a Bayesian framework have been developed to predict the mechanical properties of alpha/beta Ti alloys. The development of such rules-based model requires the population of extensive databases, which in the present case are microstructurally-based. The steps involved in database development include producing controlled variations of the microstructure using novel approaches to heat-treatments, the use of standardized stereology protocols to characterize and quantify microstructural features rapidly, and mechanical testing of the heat-treated specimens. These databases have been used to train and test NN Models for prediction of mechanical properties. In addition, these models have been used to identify the influence of individual microstructural features on the mechanical properties, consequently guiding the efforts towards development of more robust mechanistically based models. In order to understand the property-microstructure relationships, a detailed understanding of microstructure evolution is imperative. The crystallography of the microstructure developing as a result of the solid-state beta → beta+alpha transformation has been studied in detail by employing Scanning Electron Microscopy (SEM), Orientation Imaging Microscopy (in a high resolution SEM), site-specific TEM sample preparation using focused ion beam, and TEM based techniques. The influence of variant selection on the evolution of microstructure will be specifically addressed.

  16. Mechanical properties of self-curing concrete (SCUC

    Directory of Open Access Journals (Sweden)

    Magda I. Mousa

    2015-12-01

    Full Text Available The mechanical properties of concrete containing self-curing agents are investigated in this paper. In this study, two materials were selected as self-curing agents with different amounts, and the addition of silica fume was studied. The self-curing agents were, pre-soaked lightweight aggregate (Leca; 0.0%, 10%, 15%, and 20% of volume of sand; or polyethylene-glycol (Ch.; 1%, 2%, and 3% by weight of cement. To carry out this study the cement content of 300, 400, 500 kg/m3, water/cement ratio of 0.5, 0.4, 0.3 and 0.0%, 15% silica fume of weight of cement as an additive were used in concrete mixes. The mechanical properties were evaluated while the concrete specimens were subjected to air curing regime (in the laboratory environment with 25 °C, 65% R.H. during the experiment. The results show that, the use of self-curing agents in concrete effectively improved the mechanical properties. The concrete used polyethylene-glycol as self-curing agent, attained higher values of mechanical properties than concrete with saturated Leca. In all cases, either 2% Ch. or 15% Leca was the optimum ratio compared with the other ratios. Higher cement content and/or lower water/cement ratio lead(s to more efficient performance of self-curing agents in concrete. Incorporation of silica fume into self-curing concrete mixture enhanced all mechanical properties, not only due to its pozzolanic reaction, but also due to its ability to retain water inside concrete.

  17. Ultrasonic evaluation of the physical and mechanical properties of granites.

    Science.gov (United States)

    Vasconcelos, G; Lourenço, P B; Alves, C A S; Pamplona, J

    2008-09-01

    Masonry is the oldest building material that survived until today, being used all over the world and being present in the most impressive historical structures as an evidence of spirit of enterprise of ancient cultures. Conservation, rehabilitation and strengthening of the built heritage and protection of human lives are clear demands of modern societies. In this process, the use of nondestructive methods has become much common in the diagnosis of structural integrity of masonry elements. With respect to the evaluation of the stone condition, the ultrasonic pulse velocity is a simple and economical tool. Thus, the central issue of the present paper concerns the evaluation of the suitability of the ultrasonic pulse velocity method for describing the mechanical and physical properties of granites (range size between 0.1-4.0 mm and 0.3-16.5 mm) and for the assessment of its weathering state. The mechanical properties encompass the compressive and tensile strength and modulus of elasticity, and the physical properties include the density and porosity. For this purpose, measurements of the longitudinal ultrasonic pulse velocity with distinct natural frequency of the transducers were carried out on specimens with different size and shape. A discussion of the factors that induce variations on the ultrasonic velocity is also provided. Additionally, statistical correlations between ultrasonic pulse velocity and mechanical and physical properties of granites are presented and discussed. The major output of the work is the confirmation that ultrasonic pulse velocity can be effectively used as a simple and economical nondestructive method for a preliminary prediction of mechanical and physical properties, as well as a tool for the assessment of the weathering changes of granites that occur during the serviceable life. This is of much interest due to the usual difficulties in removing specimens for mechanical characterization.

  18. Mechanical properties of Nd-Ba-Cu-O bulk superconductors

    International Nuclear Information System (INIS)

    Matsui, Motohide; Sakai, Naomichi; Murakami, Masato; Osamura, Kozo

    2003-01-01

    We investigated the effects of Nd422 and Ag particles on the mechanical properties in Nd-Ba-Cu-O bulk superconductors. Both Nd422 and Ag particles were effective in decreasing the amount of microcracks running along the c direction. In the case of Nd422, however, excessive Nd422 addition enhanced the crack propagation, resulting in the degradation of mechanical strength. In the case of Ag addition, the beneficial effect of its ductile mechanical property was not observed. This was due to a relatively large size of Ag particles and low interfacial strength between Ag and Nd123 matrix. It was remarkable that the Weibull coefficient of the sample with Ag 2 O addition exceeded 13, which is reliable enough for practical engineering applications

  19. An Introduction to the Mechanical Properties of Ceramics

    Science.gov (United States)

    Green, David J.

    1998-09-01

    Over the past twenty-five years ceramics have become key materials in the development of many new technologies as scientists have been able to design these materials with new structures and properties. An understanding of the factors that influence their mechanical behavior and reliability is essential. This book will introduce the reader to current concepts in the field. It contains problems and exercises to help readers develop their skills. This is a comprehensive introduction to the mechanical properties of ceramics, and is designed primarily as a textbook for advanced undergraduates in materials science and engineering. It will also be of value as a supplementary text for more general courses and to industrial scientists and engineers involved in the development of ceramic-based products, materials selection and mechanical design.

  20. Mechanical properties of amorphous and polycrystalline multilayer systems

    International Nuclear Information System (INIS)

    Barzen, I.; Edinger, M.; Scherer, J.; Ulrich, S.; Jung, K.; Ehrhardt, H.

    1993-01-01

    Amorphous and polycrystalline multilayer structures containing materials with metallic (Cr, Cr 3 C 2 ), ionic (Al 2 O 3 ) and covalent (SiC) bonding have been prepared by magnetron sputtering and ion plating in a dual-source apparatus. Up to 1000 layers have been deposited with a constant total thickness of 2.3 μm. Below a single-layer thickness of 10-30 nm the mechanical properties stress and hardness show strong variations. On one hand it is possible that below a certain thickness the mechanical properties of a single layer change. On the other hand electrical resistance and electron spin density measurements indicate that electronic effects may be involved. An attempt is made to explain the observed correlations by transport mechanisms of the electrons, by saturation of dangling bonds with delocalized electrons and by changes in the electronic band structure. (orig.)

  1. Bioinspired Bouligand cellulose nanocrystal composites: a review of mechanical properties

    Science.gov (United States)

    Natarajan, Bharath; Gilman, Jeffrey W.

    2017-12-01

    The twisted plywood, or Bouligand, structure is the most commonly observed microstructural motif in natural materials that possess high mechanical strength and toughness, such as that found in bone and the mantis shrimp dactyl club. These materials are isotropically toughened by a low volume fraction of soft, energy-dissipating polymer and by the Bouligand structure itself, through shear wave filtering and crack twisting, deflection and arrest. Cellulose nanocrystals (CNCs) are excellent candidates for the bottom-up fabrication of these structures, as they naturally self-assemble into `chiral nematic' films when cast from solutions and possess outstanding mechanical properties. In this article, we present a review of the fabrication techniques and the corresponding mechanical properties of Bouligand biomimetic CNC nanocomposites, while drawing comparison to the performance standards set by tough natural composite materials. This article is part of a discussion meeting issue `New horizons for cellulose nanotechnology'.

  2. Mechanical properties of polyelectrolyte multilayer self-assembled films

    International Nuclear Information System (INIS)

    Dai Xinhua; Zhang Yongjun; Guan Ying; Yang Shuguang; Xu Jian

    2005-01-01

    The mechanical properties of electrostatic self-assembled multilayer films from polyacrylic acid (PAA) and C 60 -ethylenediamine adduct (C 60 -EDA) or poly(allylamine hydrochloride) (PAH) were evaluated by atomic force microscopy (AFM) wear experiments. Because of the higher molecular weight of PAH, the wear resistance of the (PAH/PAA) 10 film is higher than that of the (PAH/PAA) 2 (C 60 -EDA/PAA) 8 film; that is, the former is mechanically more stable than the latter. The mechanical stability of both films can be improved significantly by heat treatment, which changes the nature of the linkage from ionic to covalent. The AFM measurement also reveals that the (PAH/PAA) 2 (C 60 -EDA/PAA) 8 film is softer than the (PAH/PAA) 10 film. The friction properties of the heated films were measured. These films can be developed as potential lubrication coatings for microelectromechanical systems

  3. Bentonite Permeability at Elevated Temperature

    Directory of Open Access Journals (Sweden)

    Katherine A. Daniels

    2017-01-01

    Full Text Available Repository designs frequently favour geological disposal of radioactive waste with a backfill material occupying void space around the waste. The backfill material must tolerate the high temperatures produced by decaying radioactive waste to prevent its failure or degradation, leading to increased hydraulic conductivity and reduced sealing performance. The results of four experiments investigating the effect of temperature on the permeability of a bentonite backfill are presented. Bentonite is a clay commonly proposed as the backfill in repository designs because of its high swelling capacity and very low permeability. The experiments were conducted in two sets of purpose-built, temperature controlled apparatus, designed to simulate isotropic pressure and constant volume conditions within the testing range of 4–6 MPa average effective stress. The response of bentonite during thermal loading at temperatures up to 200 °C was investigated, extending the previously considered temperature range. The results provide details of bentonite’s intrinsic permeability, total stress, swelling pressure and porewater pressure during thermal cycles. We find that bentonite’s hydraulic properties are sensitive to thermal loading and the type of imposed boundary condition. However, the permeability change is not large and can mostly be accounted for by water viscosity changes. Thus, under 150 °C, temperature has a minimal impact on bentonite’s hydraulic permeability.

  4. Structure, Mechanics and Flow Properties of Fractured Shale: Core-Scale Experimentation and In-situ Imaging

    Science.gov (United States)

    Abdelmalek, B. F.; Karpyn, Z.; Liu, S.

    2014-12-01

    Over the last several years, hydrocarbon exploitation and development in North America has been heavily centered on shale gas plays. However, the physical attributes of shales and their manifestation on transport properties and storage capacity remain poorly understood. Therefore, more experimentally based data are needed to fill the gaps in understanding both transport and storage of fluids in shale. The proposed work includes installation and testing of an experimental system which is capable of monitoring the dynamic evolution of shale core permeability under variable loading conditions and in coordination with X-ray microCT imaging. The goal of this study is to better understand and quantify fluid flow patterns and associated transport dynamics of fractured shale samples. The independent variables considered in this study are: mechanical loading and pore pressure. The mechanical response of shale core is captured for different loading paths. To best replicate the in-situ production scenario, the pore pressure is progressively depleted to mimic pressure decline. During the course of experimentation, permeability is estimated using the pulse-decay method under tri-axial stress boundary conditions. Simultaneously, X-ray microCT imaging is used with a tracer gas that is allowed to flow through the sample as an illuminating agent. In the presence of an illuminating agent, either Xenon or Krypton, the X-ray CT scanner can image fractures, global pathways and diffusional fronts in the matrix, as well as sorption sites that reflect heterogeneities in the sample and localized deformation. Anticipated results from these experiments will help quantify permeability evolution as a function of different loading conditions and pore pressure depletion. Also, the X-ray images will help visualize the change of flow patterns and the intensity of sorption as a function of mechanical loading and pore pressure.

  5. Data-driven fault mechanics: Inferring fault hydro-mechanical properties from in situ observations of injection-induced aseismic slip

    Science.gov (United States)

    Bhattacharya, P.; Viesca, R. C.

    2017-12-01

    In the absence of in situ field-scale observations of quantities such as fault slip, shear stress and pore pressure, observational constraints on models of fault slip have mostly been limited to laboratory and/or remote observations. Recent controlled fluid-injection experiments on well-instrumented faults fill this gap by simultaneously monitoring fault slip and pore pressure evolution in situ [Gugleilmi et al., 2015]. Such experiments can reveal interesting fault behavior, e.g., Gugleilmi et al. report fluid-activated aseismic slip followed only subsequently by the onset of micro-seismicity. We show that the Gugleilmi et al. dataset can be used to constrain the hydro-mechanical model parameters of a fluid-activated expanding shear rupture within a Bayesian framework. We assume that (1) pore-pressure diffuses radially outward (from the injection well) within a permeable pathway along the fault bounded by a narrow damage zone about the principal slip surface; (2) pore-pressure increase ativates slip on a pre-stressed planar fault due to reduction in frictional strength (expressed as a constant friction coefficient times the effective normal stress). Owing to efficient, parallel, numerical solutions to the axisymmetric fluid-diffusion and crack problems (under the imposed history of injection), we are able to jointly fit the observed history of pore-pressure and slip using an adaptive Monte Carlo technique. Our hydrological model provides an excellent fit to the pore-pressure data without requiring any statistically significant permeability enhancement due to the onset of slip. Further, for realistic elastic properties of the fault, the crack model fits both the onset of slip and its early time evolution reasonably well. However, our model requires unrealistic fault properties to fit the marked acceleration of slip observed later in the experiment (coinciding with the triggering of microseismicity). Therefore, besides producing meaningful and internally consistent

  6. Antifungal, Mechanical, and Physical Properties of Edible Film Containing Williopsis saturnus var. saturnus Antagonistic Yeast.

    Science.gov (United States)

    Karabulut, Gulsah; Cagri-Mehmetoglu, Arzu

    2018-03-01

    The molding of food products causing health risks is a main problem in the food industry. In this study, as an alternative solution for preventing mold growth, an antifungal edible film was developed by incorporating Williopsis saturnus var. saturnus (0; 3; 7; and 9 logs CFU/cm 2 ) into whey protein concentrate (WPC) based films. Antifungal properties of the films against Penicilium expansum and Aspergillus niger were analyzed using the disc diffusion method. Physical (barrier, solubility, color), mechanical (tensile strength and percent elongation) properties of the films as well as the survival of W. saturnus in the film were assessed during 28 days of storage at 23 °C. According to the results, the viability of W. saturnus (7 and 9 logs CFU/cm 2 ) in WPC films stored for 28 days under vacuum or non-vacuum decreased to 36% and 60%, respectively. In addition, films containing W. saturnus decreased the viability of P. expansum and A. niger by 29% and 19%, respectively. Adding yeast did not change the tensile strength (P > 0.05), but significantly decreased % elongation and increased water vapor and oxygen permeability and water solubility (P films may be useful for inhibiting mold growth on foods. © 2018 Institute of Food Technologists®.

  7. Characterization of starch films containing starch nanoparticles: part 1: physical and mechanical properties.

    Science.gov (United States)

    Shi, Ai-Min; Wang, Li-Jun; Li, Dong; Adhikari, Benu

    2013-07-25

    We report, for the first time, the preparation method and characteristics of starch films incorporating spray dried and vacuum freeze dried starch nanoparticles. Physical properties of these films such as morphology, crystallinity, water vapor permeability (WVP), opacity, and glass transition temperature (Tg) and mechanical properties (strain versus temperature, strain versus stress, Young's modulus and toughness) were measured. Addition of both starch nanoparticles in starch films increased roughness of surface, lowered degree of crystallinity by 23.5%, WVP by 44% and Tg by 4.3°C, respectively compared to those of starch-only films. Drying method used in preparation of starch nanoparticles only affected opacity of films. The incorporation of nanoparticles in starch films resulted into denser films due to which the extent of variation of strain with temperature was much lower. The toughness and Young's modulus of films containing both types of starch nanoparticles were lower than those of control films especially at <100°C. Copyright © 2012 Elsevier Ltd. All rights reserved.

  8. Mechanical properties of molybdenum-sealing glass-ceramics

    International Nuclear Information System (INIS)

    Swearengen, J.C.; Eagan, R.J.

    1975-07-01

    Elastic constants, thermal expansion, strength, and fracture toughness were determined for a molybdenum-sealing glass-ceramic containing approximately 31 volume percent Zn 2 SiO 4 crystals in a glass matrix. The microstructure was studied for two different crystallization treatments and moderate changes in composition. Mechanical properties of the composite were compared with the properties of the constituent phases through application of mixture theory and by fractographic observations. The reinforcing effects of the crystal phase at room temperature are evident in comparison with the properties of the residual glass but not necessarily in comparison with the parent glass. Fracture toughness of the composite depends primarily upon additive properties of the separate phases instead of by interactive effects such as microcracks. (U.S.)

  9. DNA origami compliant nanostructures with tunable mechanical properties.

    Science.gov (United States)

    Zhou, Lifeng; Marras, Alexander E; Su, Hai-Jun; Castro, Carlos E

    2014-01-28

    DNA origami enables fabrication of precise nanostructures by programming the self-assembly of DNA. While this approach has been used to make a variety of complex 2D and 3D objects, the mechanical functionality of these structures is limited due to their rigid nature. We explore the fabrication of deformable, or compliant, objects to establish a framework for mechanically functional nanostructures. This compliant design approach is used in macroscopic engineering to make devices including sensors, actuators, and robots. We build compliant nanostructures by utilizing the entropic elasticity of single-stranded DNA (ssDNA) to locally bend bundles of double-stranded DNA into bent geometries whose curvature and mechanical properties can be tuned by controlling the length of ssDNA strands. We demonstrate an ability to achieve a wide range of geometries by adjusting a few strands in the nanostructure design. We further developed a mechanical model to predict both geometry and mechanical properties of our compliant nanostructures that agrees well with experiments. Our results provide a basis for the design of mechanically functional DNA origami devices and materials.

  10. Potato Starch/Montmorillonite-Based Nanocomposites: Water Sensitivity, Mechanical and Thermal Properties and XRD Profile Study

    Directory of Open Access Journals (Sweden)

    Ronak Gholami

    2013-06-01

    Full Text Available Studies were carried out on the effect of adding different percentages of montmorillonite (3, 5, 7 and 9% of starch weight on the physical properties of potato starch-MMT nanocomposites. Heat resistance and mechanical properties of films were measured by differential scanning calorimetry (DSC and tensile test. Nanoparticles distribution in polymer matrix was investigated using X-ray diffraction test (XRD. For investigation of water vapor resistance of film samples, moisture sorption and water vapor permeability (WVP were measured. The results showed that the distribution of nanoparticles in the polymer matrix was exfoliated. WVP in pure starch films was 2.62×10-7 g/mhPa and with the addition of 9% MMT it was reduced to 1.43×10-7 g/mhPa. With the addition of nanoclay from zero to 9%, the ultimate tensile strength of nanocomposite samples was increased from 5.9 to 6.63 MPa and strain-to-break was decreased from 34.82 to 26.83%. But the rising trend was not significant for nanocomposite samples containing low concentrations of nanoclay (0-7%. The main reasons for the enhancement of mechanical properties due to the addition of nanoclay were to establish hydrogen bonding between polymer chains and clay layers, filling the empty spaces and increase the crystalline domains. Investigation of thermal resistance of nanocomposite samples showed that they have higher thermal resistance and melting point in comparison with pure starch films. With the addition of nanoclay from zero to 9%, the melting point of film samples was increased from 218 to 232.1°C. With the addition of nanoclay, probably the mobility of amylopectin chains decreased and crystalline domains increased. Also, with increasing nanoclay content, the glass transition temperature of nanocomposite samples was increased. This result corresponded to shrinkage in free volume and thus reduction in the polymer chains mobility in amorphous regions.

  11. Antimicrobial and physical-mechanical properties of agar-based films incorporated with grapefruit seed extract.

    Science.gov (United States)

    Kanmani, Paulraj; Rhim, Jong-Whan

    2014-02-15

    The use of synthetic petroleum based packaging films caused serious environmental problems due to their difficulty in recycling and poor biodegradability. Therefore, present study was aimed to develop natural biopolymer-based antimicrobial packaging films as an alternative for the synthetic packaging films. As a natural antimicrobial agent, grapefruit seed extract (GSE) has been incorporated into agar to prepare antimicrobial packaging film. The films with different concentrations of GSE were prepared by a solvent casting method and the resulting composite films were examined physically and mechanically. In addition, the films were characterized by FE-SEM, XRD, FT-IR and TGA. The incorporation of GSE caused increase in color, UV barrier, moisture content, water solubility and water vapor permeability, while decrease in surface hydrophobicity, tensile strength and elastic modulus of the films. As the concentration of GSE increased from 0.6 to 13.3 μg/mL, the physical and mechanical properties of the films were affected significantly. The addition of GSE changed film microstructure of the film, but did not influence the crystallinity of agar and thermal stability of the agar-based films. The agar/GSE films exhibited distinctive antimicrobial activity against three test food pathogens, such as Listeria monocytogenes, Bacillus cereus and Escherichia coli. These results suggest that agar/GSE films have potential to be used in an active food packaging systems for maintaining food safety and extending the shelf-life of the packaged food. Copyright © 2013 Elsevier Ltd. All rights reserved.

  12. Mechanical Properties in a Bamboo Fiber/PBS Biodegradable Composite

    Science.gov (United States)

    Ogihara, Shinji; Okada, Akihisa; Kobayashi, Satoshi

    In recent years, biodegradable plastics which have low effect on environment have been developed. However, many of them have lower mechanical properties than conventional engineering plastics. Reinforcing them with a natural fiber is one of reinforcing methods without a loss of their biodegradability. In the present study, we use a bamboo fiber as the reinforcement and polybutylenesuccinate (PBS) as the matrix. We fabricate long fiber unidirectional composites and cross-ply laminate with different fiber weight fractions (10, 20, 30, 40 and 50wt%). We conduct tensile tests to evaluate the mechanical properties of these composites. In addition, we measure bamboo fiber strength distribution. We discuss the experimentally-obtained properties based on the mechanical properties of the constituent materials. Young's modulus and tensile strength in unidirectional composite and cross-ply laminate increase with increasing fiber weight fraction. However, the strain at fracture showed decreasing tendency. Young's modulus in fiber and fiber transverse directions are predictable by the rules of mixture. Tensile strength in fiber direction is lower than Curtin's prediction of strength which considers distribution of fiber strength. Young's modulus in cross-ply laminate is predictable by the laminate theory. However, analytical prediction of Poisson's ratio in cross-ply laminate by the laminate theory is lower than the experimental results.

  13. Enhancement of mechanical properties of epoxy/graphene nanocomposite

    Science.gov (United States)

    Berhanuddin, N. I. C.; Zaman, I.; Rozlan, S. A. M.; Karim, M. A. A.; Manshoor, B.; Khalid, A.; Chan, S. W.; Meng, Q.

    2017-10-01

    Graphene is a novel class of nanofillers possessing outstanding characteristics including most compatible with most polymers, high absolute strength, high aspect ratio and cost effectiveness. In this study, graphene was used to reinforce epoxy as a matrix, to enhance its mechanical properties. Two types of epoxy composite were developed which are epoxy/graphene nanocomposite and epoxy/modified graphene nanocomposite. The fabrication of graphene was going through thermal expansion and sonication process. Chemical modification was only done for modified graphene where 4,4’-Methylene diphenyl diisocyanate (MDI) is used. The mechanical properties of both nanocomposite, such as Young’s modulus and maximum stress were investigated. Three weight percentage were used for this study which are 0.5 wt%, 1.0 wt% and 1.5 wt%. At 0.5 wt%, modified and unmodified shows the highest value compared to neat epoxy, where the value were 8 GPa, 6 GPa and 0.675 GPa, respectively. For maximum stress, neat epoxy showed the best result compared to both nanocomposite due to the changes of material properties when adding the filler into the matrix. Therefore, both nanocomposite increase the mechanical properties of the epoxy, however modification surface of graphene gives better improvement.

  14. Mechanical Properties of Nanostructured Materials Determined Through Molecular Modeling Techniques

    Science.gov (United States)

    Clancy, Thomas C.; Gates, Thomas S.

    2005-01-01

    The potential for gains in material properties over conventional materials has motivated an effort to develop novel nanostructured materials for aerospace applications. These novel materials typically consist of a polymer matrix reinforced with particles on the nanometer length scale. In this study, molecular modeling is used to construct fully atomistic models of a carbon nanotube embedded in an epoxy polymer matrix. Functionalization of the nanotube which consists of the introduction of direct chemical bonding between the polymer matrix and the nanotube, hence providing a load transfer mechanism, is systematically varied. The relative effectiveness of functionalization in a nanostructured material may depend on a variety of factors related to the details of the chemical bonding and the polymer structure at the nanotube-polymer interface. The objective of this modeling is to determine what influence the details of functionalization of the carbon nanotube with the polymer matrix has on the resulting mechanical properties. By considering a range of degree of functionalization, the structure-property relationships of these materials is examined and mechanical properties of these models are calculated using standard techniques.

  15. Unique microstructure and excellent mechanical properties of ADI

    Directory of Open Access Journals (Sweden)

    Jincheng Liu

    2006-11-01

    Full Text Available Amongst the cast iron family, ADI has a unique microstructure and an excellent, optimised combination of mechanical properties. The main microstructure of ADI is ausferrite, which is a mixture ofextremely fine acicular ferrite and stable, high carbon austenite. There are two types of austenite in ADI:(1 the coarser and more equiaxed blocks of austenite between non-parallel acicular structures, which exist mainly in the last solidified area, and (2 the thin films of ustenite between the individual ferriteplatelets in the acicular structure. It is this unique microstructure, which gives ADI its excellent static and dynamic properties, and good low temperature impact toughness. The effect of microstructure on the mechanical properties is explained in more detail by examining the microstructure at the atomic scale. Considering the nanometer grain sizes, the unique microstructure, the excellent mechanical properties,good castability, (which enables near net shape components to be produced economically and in large volumes, and the fact that it can be 100% recycled, it is not overemphasized to call ADI a high-tech,nanometer and “green” material. ADI still has the potential to be further improved and its production and the number of applications for ADI will continue to grow, driven by the resultant cost savings over alternative materials.

  16. Evaluation of permeability and swelling pressure of compacted bentonite using a calcium hydroxide solution

    International Nuclear Information System (INIS)

    Aoyagi, Takayoshi; Maeda, Munehiro; Mihara, Morihiro; Tanaka, Masuhiro

    1998-12-01

    Tests to determine the swelling pressure, permeability, compressive strength and elastic modulus of Ca-Na exchanged bentonite, Na-bentonite and Ca-bentonite at the Power Reactor and Nuclear Fuel Development Corporation have mainly used distilled water. However, disposal facilities for TRU waste will use cementateous material for packaging, backfill as well as structural support. In this case, a large amount of calcium will dissolve in groundwater flowing through the cementateous material. Therefore, it is important to investigate the mechanical properties of bentonite in calcium-rich water as part of the disposal research program for TRU waste. In order to understand the effect of the chemical composition of water on the basic mechanical properties of bentonite - part of evaluating the disposal concepts for TRU waste disposal - we tested the permeability of compacted bentonite under saturated conditions using a calcium hydroxide solution. The aqueous solution represents water dominated by the calcium component. Na-bentonite, Ca-Na exchanged bentonite and Ca-bentonite were used for swelling pressure measurement tests and permeability testing. Measures of the maximum and equilibrium swelling pressure as well as permeability we obtained. The dry density of bentonite was varied between tests. Results show that swelling pressure and permeability are dependent on dry density. In separate tests using Ca-bentonite, the bentonite-mixing rate was varied as an independent parameter. Results show that there is little change in the swelling pressure and permeability between tests using calcium hydroxide solution and distilled water for all bentonite types. (author)

  17. Coupled thermo-hydro-mechanical calculations of the water saturation phase of a KBS-3 deposition hole. Influence of hydraulic rock properties on the water saturation phase

    International Nuclear Information System (INIS)

    Boergesson, Lennart; Hernelind, J.

    1999-12-01

    The wetting process in deposition holes designed according to the KBS-3-concept has been simulated with finite element calculations of the thermo-hydro-mechanical processes in the buffer, backfill and surrounding rock. The buffer material has been modelled according to the preliminary material models developed for swelling clay. The properties of the rock have been varied in order to investigate the influence of the rock properties and the hydraulic conditions on the wetting processes. In the modelling of the test holes the permeability of the rock matrix, the water supply from the backfill, the water pressure in the surrounding rock, the permeability of the disturbed zone around the deposition hole, the water retention properties of the rock, and the transmissivity of two fractures intersecting the deposition hole have been varied. The calculations indicate that the wetting takes about 5 years if the water pressure in the rock is high and if the permeability of the rock is so high that the properties of the bentonite determine the wetting rate. However, it may take considerably more than 30 years if the rock is very tight and the water pressure in the rock is low. The calculations also show that the influence of the rock structure is rather large except for the influence of the transmissivity T of the fractures, which turned out to be insignificant for the values used in the calculations

  18. Mechanical Properties of a Bainitic Steel Producible by Hot Rolling

    Directory of Open Access Journals (Sweden)

    Rana R.

    2017-12-01

    Full Text Available A carbide-free bainitic microstructure is suitable for achieving a combination of ultra high strength and high ductility. In this work, a steel containing nominally 0.34C-2Mn-1.5Si-1Cr (wt.% was produced via industrial hot rolling and laboratory heat treatments. The austenitization (900°C, 30 min. and austempering (300-400°C, 3 h treatments were done in salt bath furnaces. The austempering treatments were designed to approximately simulate the coiling step, following hot rolling and run-out-table cooling, when the bainitic transformation would take place and certain amount of austenite would be stabilized due to suppression of carbide precipitation. The microstructures and various mechanical properties (tensile properties, bendability, flangeability, and room and subzero temperature impact toughness relevant for applications were characterized. It was found that the mechanical properties were highly dependent on the stability of the retained austenite, presence of martensite in the microstructure and the size of the microstructural constituents. The highest amount of retained austenite (~ 27 wt.% was obtained in the sample austempered at 375°C but due to lower austenite stability and coarser overall microstructure, the sample exhibited lower tensile ductility, bendability, flangeability and impact toughness. The sample austempered at 400°C also showed poor properties due to the presence of initial martensite and coarse microstructure. The best combination of mechanical properties was achieved for the samples austempered at 325-350°C with a lower amount of retained austenite but with the highest mechanical stability.

  19. Effect of cold drawing on mechanical properties of biodegradable fibers.

    Science.gov (United States)

    La Mantia, Francesco Paolo; Ceraulo, Manuela; Mistretta, Maria Chiara; Morreale, Marco

    2017-01-26

    Biodegradable polymers are currently gaining importance in several fields, because they allow mitigation of the impact on the environment related to disposal of traditional, nonbiodegradable polymers, as well as reducing the utilization of oil-based sources (when they also come from renewable resources). Fibers made of biodegradable polymers are of particular interest, though, it is not easy to obtain polymer fibers with suitable mechanical properties and to tailor these to the specific application. The main ways to tailor the mechanical properties of a given biodegradable polymer fiber are based on crystallinity and orientation control. However, crystallinity can only marginally be modified during processing, while orientation can be controlled, either during hot drawing or cold stretching. In this paper, a systematic investigation of the influence of cold stretching on the mechanical and thermomechanical properties of fibers prepared from different biodegradable polymer systems was carried out. Rheological and thermal characterization helped in interpreting the orientation mechanisms, also on the basis of the molecular structure of the polymer systems. It was found that cold drawing strongly improved the elastic modulus, tensile strength and thermomechanical resistance of the fibers, in comparison with hot-spun fibers. The elastic modulus showed higher increment rates in the biodegradable systems upon increasing the draw ratio.

  20. Zirconia based dental ceramics: structure, mechanical properties, biocompatibility and applications.

    Science.gov (United States)

    Gautam, Chandkiram; Joyner, Jarin; Gautam, Amarendra; Rao, Jitendra; Vajtai, Robert

    2016-12-06

    Zirconia (ZrO 2 ) based dental ceramics have been considered to be advantageous materials with adequate mechanical properties for the manufacturing of medical devices. Due to its very high compression strength of 2000 MPa, ZrO 2 can resist differing mechanical environments. During the crack propagation on the application of stress on the surface of ZrO 2 , a crystalline modification diminishes the propagation of cracks. In addition, zirconia's biocompatibility has been studied in vivo, leading to the observation of no adverse response upon the insertion of ZrO 2 samples into the bone or muscle. In vitro experimentation has exhibited the absence of mutations and good viability of cells cultured on this material leading to the use of ZrO 2 in the manufacturing of hip head prostheses. The mechanical properties of zirconia fixed partial dentures (FPDs) have proven to be superior to other ceramic/composite restorations and hence leading to their significant applications in implant supported rehabilitations. Recent developments were focused on the synthesis of zirconia based dental materials. More recently, zirconia has been introduced in prosthetic dentistry for the fabrication of crowns and fixed partial dentures in combination with computer aided design/computer aided manufacturing (CAD/CAM) techniques. This systematic review covers the results of past as well as recent scientific studies on the properties of zirconia based ceramics such as their specific compositions, microstructures, mechanical strength, biocompatibility and other applications in dentistry.

  1. Effects of pore design on mechanical properties of nanoporous silicon

    International Nuclear Information System (INIS)

    Winter, Nicholas; Becton, Matthew; Zhang, Liuyang; Wang, Xianqiao

    2017-01-01

    Nanoporous silicon has been emerging as a powerful building block for next-generation sensors, catalysts, transistors, and tissue scaffolds. The capability to design novel devices with desired mechanical properties is paramount to their reliability and serviceability. In order to bring further resolution to the highly variable mechanical characteristics of nanoporous silicon, here we perform molecular dynamics simulations to study the effects of ligament thickness, relative density, and pore geometry/orientation on the mechanical properties of nanoporous silicon, thereby determining its Young's modulus, ultimate strength, and toughness as well as the scaling laws versus the features of interior ligaments. Results show that pore shape and pattern dictate stress accumulation inside the designed structure, leading to the corresponding failure signature, such as stretching-dominated, bending-dominated, or stochastic failure signatures, in nanoporous silicon. The nanostructure of the material is also seen to drive or mute size effects such as “smaller is stronger” and “smaller is ductile”. This investigation provides useful insight into the behavior of nanoporous silicon and how one might leverage its promising applications. - Graphical abstract: Molecular dynamics simulations are performed to study the effects of ligament thickness, relative density, and pore geometry/orientation on the mechanical properties of nanoporous silicon, thereby determining its Young's modulus, ultimate strength, and toughness as well as the scaling trends versus the features of interior ligaments.

  2. Mechanical and electronic properties of Janus monolayer transition metal dichalcogenides

    Science.gov (United States)

    Shi, Wenwu; Wang, Zhiguo

    2018-05-01

    The mechanical and electronic properties of Janus monolayer transition metal dichalcogenides MXY (M  =  Ti, Zr, Hf, V, Nb, Ta, Cr, Mo, W; X/Y  =  S, Se, Te) were investigated using density functional theory. Results show that breaking the out-of-plane structural symmetry can be used to tune the electronic and mechanical behavior of monolayer transition metal dichalcogenides. The band gaps of monolayer WXY and MoXY are in the ranges of 0.16–1.91 and 0.94–1.69 eV, respectively. A semiconductor to metallic phase transition occurred in Janus monolayer MXY (M  =  Ti, Zr and Hf). The monolayers MXY (M  =  V, Nb, Ta and Cr) show metallic characteristics, which show no dependence on the structural symmetry breaking. The mechanical properties of MXY depended on the composition. Monolayer MXY (M  =  Mo, Ti, Zr, Hf and W) showed brittle characteristic, whereas monolayer CrXY and VXY are with ductile characteristic. The in-plane stiffness of pristine and Janus monolayer MXY are in the range between 22 and 158 N m‑1. The tunable electronic and mechanical properties of these 2D materials would advance the development of ultra-sensitive detectors, nanogenerators, low-power electronics, and energy harvesting and electromechanical systems.

  3. Numerical analysis of thermal impact on hydro-mechanical properties of clay

    Directory of Open Access Journals (Sweden)

    Xuerui Wang

    2014-10-01

    Full Text Available As is known, high-level radioactive waste (HLW is commonly heat-emitting. Heat output from HLW will dissipate through the surrounding rocks and induce complex thermo-hydro-mechanical-chemical (THMC processes. In highly consolidated clayey rocks, thermal effects are particularly significant because of their very low permeability and water-saturated state. Thermal impact on the integrity of the geological barriers is of most importance with regard to the long-term safety of repositories. This study focuses on numerical analysis of thermal effects on hydro-mechanical properties of clayey rock using a coupled thermo-mechanical multiphase flow (TH2M model which is implemented in the finite element programme OpenGeoSys (OGS. The material properties of the numerical model are characterised by a transversal isotropic elastic model based on Hooke's law, a non-isothermal multiphase flow model based on van Genuchten function and Darcy's law, and a transversal isotropic heat transport model based on Fourier's law. In the numerical approaches, special attention has been paid to the thermal expansion of three different phases: gas, fluid and solid, which could induce changes in pore pressure and porosity. Furthermore, the strong swelling and shrinkage behaviours of clayey material are also considered in the present model. The model has been applied to simulate a laboratory heating experiment on claystone. The numerical model gives a satisfactory representation of the observed material behaviour in the laboratory experiment. The comparison of the calculated results with the laboratory findings verifies that the simulation with the present numerical model could provide a deeper understanding of the observed effects.

  4. Mechanical properties of roll extruded nuclear reactor piping

    International Nuclear Information System (INIS)

    Steichen, J.M.; Knecht, R.L.

    1975-01-01

    The elevated temperature mechanical properties of large diameter (28 inches) seamless pipe produced by roll extrusion for use as primary piping for sodium coolant in the Fast Flux Test Facility (FFTF) have been characterized. The three heats of Type 316H stainless steel piping material used exhibited consistent mechanical properties and chemical compositions. Tensile and creep-rupture properties exceeded values on which the allowable stresses for ASME Code Case 1592 on Nuclear Components in Elevated Temperature Service were based. Tensile strength and ductility were essentially unchanged by aging in static sodium at 1050 0 F for times to 10,000 hours. High strain rate tensile tests showed that tensile properties were insensitive to strain rate at temperatures to 900 0 F and that for temperatures of 1050 0 F and above both strength and ductility significantly increased with increasing strain rate. Fatigue-crack propagation properties were comparable to results obtained on plate material and no differences in crack propagation were found between axial and circumferential orientations. (U.S.)

  5. Relationship between Magnetic and Mechanical Properties of Cermet Tools

    International Nuclear Information System (INIS)

    Ahn, Dong Gil; Lee, Jeong Hee

    2000-01-01

    The commercial cermet cutting tools consist of multi-carbide and a binder metal of iron group, such as cobalt and nickel which are ferromagnetic. In this paper, a new approach to evaluate the mechanical properties of TiCN based cermet by magnetic properties were studied in relation to binder content and sintering conditions. The experimental cermet was prepared using commercial composition with the other binder contents by PM process. It was found that the magnetic properties of the sintered cermets remarkably depended on the microstructure and the total carbon content. The magnetic saturation was proportional to increment of coercive force. At high carbon content in sintered cermet, the magnetic saturation was increased by decreasing the concentration of solutes such as W, Mo, Ti in Co-Ni binder. As the coercive force increases, the hardness usually increases. The strength and toughness of the cermet also increased with increasing the magnetic saturation. The measurement of magnetic properties made it possible to evaluate the mechanical properties in the cermet cutting tools

  6. Physical, mechanical, and biodegradable properties of meranti wood polymer composites

    International Nuclear Information System (INIS)

    Enamul Hoque, M.; Aminudin, M.A.M.; Jawaid, M.; Islam, M.S.; Saba, N.; Paridah, M.T.

    2014-01-01

    Highlights: • In-situ polymerization and solution casting method used to manufacture WPC. • In-situ WPC exhibited better properties compared to pure wood, 5% WPC and 20% WPC. • Lowest water absorption and least biodegradability shown by In-situ wood. - Abstract: In-situ polymerization and solution casting techniques are two effective methods to manufacture wood polymer composites (WPCs). In this study, wood polymer composites (WPCs) were manufactured from meranti sapwood by solution casting and in-situ polymerization process using methyl methacrylate (MMA) and epoxy matrix respectively. Physical, mechanical, and morphological characterizations of fabricated WPCs were then carried out to analyse their properties. Morphological properties of composites samples were analyzed through scanning electron microscopy (SEM). The result reveals that in-situ wood composite exhibited better properties compared to pure wood, 5% WPC and 20% WPC. Moreover, in-situ WPC had lowest water absorption and least biodegraded. Conversely, pure wood shown moderate mechanical strength, high biodegradation and water absorption rate. In term of biodegradation, earth-medium brought more severe effect than water in deteriorating the properties of the specimens

  7. Investigation on Mechanical Properties of Graphene Oxide reinforced GFRP

    Science.gov (United States)

    Arun, G. K.; Sreenivas, Nikhil; Brahma Reddy, Kesari; Sai Krishna Reddy, K.; Shashi Kumar, M. E.; Pramod, R.

    2018-02-01

    Graphene and E-glass fibres individually find a very wide field of applications because of their various mechanical and chemical properties. Recently graphene has attracted both academic and industrial interest because it can produce a dramatic improvement in properties at very low filler content. The primary interest of this venture is to investigate on Graphene reinforced polymer matrix nanocomposites and finding the mechanical properties. The composites were fabricated by Hand Lay Process and have been evaluated by the addition of Graphene with 1, 1.5, 2, 2.5 and 3 by weight% as reinforcement in composites. The theoretical and experimental results validate the increase in properties such as tensile strength, hardness and flexural strength with increase in weight proportions from 1% to 3% of graphene powder. It was observed that the composite material with 2.5% weight fraction of graphene yielded superior properties over other weight percentages. Graphene reinforced polymer matrix nanocomposites finds its major applications in the manufacture of aircraft bodies, ballistic missiles, sporting equipment, marine applications and extraterrestrial ventures.

  8. Multiscale mechanisms of nutritionally induced property variation in spider silks

    Science.gov (United States)

    Nobbs, Madeleine; Martens, Penny J.; Tso, I-Min; Chuang, Wei-Tsung; Chang, Chung-Kai; Sheu, Hwo-Shuenn

    2018-01-01

    Variability in spider major ampullate (MA) silk properties at different scales has proven difficult to determine and remains an obstacle to the development of synthetic fibers mimicking MA silk performance. A multitude of techniques may be used to measure multiscale aspects of silk properties. Here we fed five species of Araneoid spider solutions that either contained protein or were protein deprived and performed silk tensile tests, small and wide-angle X-ray scattering (SAXS/WAXS), amino acid composition analyses, and silk gene expression analyses, to resolve persistent questions about how nutrient deprivation induces variations in MA silk mechanical properties across scales. Our analyses found that the properties of each spider’s silk varied differently in response to variations in their protein intake. We found changes in the crystalline and non-crystalline nanostructures to play specific roles in inducing the property variations we found. Across treatment MaSp expression patterns differed in each of the five species. We found that in most species MaSp expression and amino acid composition variations did not conform with our predictions based on a traditional MaSp expression model. In general, changes to the silk’s alanine and proline compositions influenced the alignment of the proteins within the silk’s amorphous region, which influenced silk extensibility and toughness. Variations in structural alignment in the crystalline and non-crystalline regions influenced ultimate strength independent of genetic expression. Our study provides the deepest insights thus far into the mechanisms of how MA silk properties vary from gene expression to nanostructure formations to fiber mechanics. Such knowledge is imperative for promoting the production of synthetic silk fibers. PMID:29390013

  9. Nanocrystalline cellulose-dispersed AKD emulsion for enhancing the mechanical and multiple barrier properties of surface-sized paper.

    Science.gov (United States)

    Yang, Luming; Lu, Sheng; Li, Juanjuan; Zhang, Fengshan; Cha, Ruitao

    2016-01-20

    In this study, we employed nanocrystalline cellulose (NCC) as an efficient dispersant to perpare alkyl ketene dimer (AKD) emulsion. The particle size and zeta potential of AKD/NCC emulsion were measured, which were approximately 5 μm and -50 mV, respectively. The surface-sized paper possessed multiple barriers properties. The air permeability of surface-sized paper was 0.29 μm/Pas and the sizing degree reached 42 s when the amount of sizing was 12.58 g/m(2) with a 96.83% decrease and a 40.00%, increase, respectively. Furthermore, the mechanical properties were optimal when the amount of sizing was about 8 g/m(2). AKD/NCC emulsion acted as a good reinforcing agent in surface-sized paper. Copyright © 2015 Elsevier Ltd. All rights reserved.

  10. Effect of ionizing radiation on physicochemical and mechanical properties of commercial multilayer coextruded flexible plastics packaging materials

    Science.gov (United States)

    Goulas, Antonios E.; Riganakos, Kyriakos A.; Kontominas, Michael G.

    2003-12-01

    The effect of gamma radiation (doses: 5, 10 and 30 kGy) on mechanical properties, gas and water vapour permeability and overall migration values into distilled water, 3% aqueous acetic acid and iso-octane was studied for a series of commercial multilayer flexible packaging materials based on coextruded polypropylene (PP), ethylene vinyl alcohol (EVOH), low-density polyethylene (LDPE), linear low-density polyethylene (LLDPE), polyamide (PA) and Ionomer. The results showed that radiation doses of 5 and 10 kGy induced no statistically significant differences ( p>0.05) in all polymer properties examined. A dose of 30 kGy induced differences ( pfilms. In addition, the same dose induced differences ( pfilms into 3% acetic acid and iso-octane and in the overall migration from PP/EVOH/LDPE-LLDPE into iso-octane. Differences recorded, are discussed in relation to food irradiation applications of respective packaging materials.

  11. Effects of oregano oil, carvacrol, cinnamaldehyde, and citral on antimicrobial, mechanical and barrier properties of carrot puree films

    Science.gov (United States)

    Wang, Xinwei; Liu, Huan; Wei, Jing; Ma, Zhongsu

    2011-02-01

    The effects against staphfloccus aureus and escherichia coli of oregano oil, carvacrol, cinnamaldehyde, and citral in chitosan-corn starch-gelatin-carrot puree films at 0.5% to 3% (w/w) concentrations were investigated along with the mechanical and barrier properties of the films. The presence of oregano oil, carvacrol, cinnamaldehyde, and citral did not change the good oxygen barrier of the films, but did significantly modify tensile properties and water vapor permeability, and made films darker. The data also show that the antimicrobial activities were in the following order: cinnamaldehyde > carvacrol > oregano oil > citral. Moreover, the antimicrobial films were more effective against staphfloccus aureus than against the escherichia coli. This study showed that oregano oil, carvacrol, cinnamaldehyde, and citral, especially the first three, could be used to prepare antimicrobial edible films for food applications.

  12. Mechanical properties and material characterization of polysialate structural composites

    Science.gov (United States)

    Foden, Andrew James

    One of the major concerns in using Fiber Reinforced Composites in applications that are subjected to fire is their resistance to high temperature. Some of the fabrics used in FRC, such as carbon, are fire resistant. However, almost all the resins used cannot withstand temperatures higher than 200°C. This dissertation deals with the development and use of a potassium aluminosilicate (GEOPOLYMER) resin that is inorganic and can sustain more than 1000°C. The results presented include the mechanical properties of the unreinforced polysialate matrix in tension, flexure, and compression as well as the strain capacities and surface energy. The mechanical properties of the matrix reinforced with several different fabrics were obtained in flexure, tension, compression and shear. The strength and stiffness of the composite was evaluated for each loading condition. Tests were conducted on unexposed samples as well as samples exposed to temperatures from 200 to 1000°C. Fatigue properties were determined using flexural loading. A study of the effect of several processing variables on the properties of the composite was undertaken to determine the optimum procedure for manufacturing composite plates. The processing variables studied were the curing temperature and pressure, and the post cure drying time required to remove any residual water. The optimum manufacturing conditions were determined using the void content, density, fiber volume fraction, and flexural strength. Analytical models are presented based on both micro and macro mechanical analysis of the composite. Classic laminate theory is used to evaluate the state of the composite as it is being loaded to determine the failure mechanisms. Several failure criteria theories are considered. The analysis is then used to explain the mechanical behavior of the composite that was observed during the experimental study.

  13. Mechanical and tribological properties of ion beam-processed surfaces

    International Nuclear Information System (INIS)

    Kodali, P.

    1998-01-01

    The intent of this work was to broaden the applications of well-established surface modification techniques and to elucidate the various wear mechanisms that occur in sliding contact of ion-beam processed surfaces. The investigation included characterization and evaluation of coatings and modified surfaces synthesized by three surface engineering methods; namely, beam-line ion implantation, plasma-source ion implantation, and DC magnetron sputtering. Correlation among measured properties such as surface hardness, fracture toughness, and wear behavior was also examined. This dissertation focused on the following areas of research: (1) investigating the mechanical and tribological properties of mixed implantation of carbon and nitrogen into single crystal silicon by beam-line implantation; (2) characterizing the mechanical and tribological properties of diamond-like carbon (DLC) coatings processed by plasma source ion implantation; and (3) developing and evaluating metastable boron-carbon-nitrogen (BCN) compound coatings for mechanical and tribological properties. The surface hardness of a mixed carbon-nitrogen implant sample improved significantly compared to the unimplanted sample. However, the enhancement in the wear factor of this sample was found to be less significant than carbon-implanted samples. The presence of nitrogen might be responsible for the degraded wear behavior since nitrogen-implantation alone resulted in no improvement in the wear factor. DLC coatings have low friction, low wear factor, and high hardness. The fracture toughness of DLC coatings has been estimated for the first time. The wear mechanism in DLC coatings investigated with a ruby slider under a contact stress of 1 GPa was determined to be plastic deformation. The preliminary data on metastable BCN compound coatings indicated high friction, low wear factor, and high hardness

  14. A study on thermal and mechanical properties of mechanically milled HDPE and PP

    International Nuclear Information System (INIS)

    Can, S.; Tan, S.

    2003-01-01

    In this study, mechanical mixing of HDPE and PP was performed via ball milling. Prepared compositions were 75/25 , 50/50 , 25/75 w/w HDPE/PP. Milling time and ball to powder ratio (B/P) were kept constant and system was cooled by adding solid CO 2 to improve the milling efficiency. To compare these systems with traditional methods, mixtures were also melt mixed by Brabender Plasti-Corder. Both milled and melt mixed systems were examined with DSC for thermal properties and tensile testing for mechanical properties Results are discussed by comparing milled , melt mixed and as-received polymers. It is observed that, unlike ball milled systems' in melt mixed systems mechanical properties are composition dependent. In addition , ball milling results in amorphization of both polymers and very high amounts of PP (75wt %) creates very amorphous HDPE structure. (Original)

  15. Evaluating mechanical properties and degradation of YTZP dental implants

    International Nuclear Information System (INIS)

    Sevilla, Pablo; Sandino, Clara; Arciniegas, Milena; Martinez-Gomis, Jordi; Peraire, Maria; Gil, Francisco Javier

    2010-01-01

    Lately new biomedical grade yttria stabilized zirconia (YTZP) dental implants have appeared in the implantology market. This material has better aesthetical properties than conventional titanium used for implants but long term behaviour of these new implants is not yet well known. The aim of this paper is to quantify the mechanical response of YTZP dental implants previously degraded under different time conditions and compare the toughness and fatigue strength with titanium implants. Mechanical response has been studied by means of mechanical testing following the ISO 14801 for Standards for dental implants and by finite element analysis. Accelerated hydrothermal degradation has been achieved by means of water vapour and studied by X-ray diffraction and nanoindentation tests. The results show that the degradation suffered by YTZP dental implants will not have a significant effect on the mechanical behaviour. Otherwise the fracture toughness of YTZP ceramics is still insufficient in certain implantation conditions.

  16. Mechanical properties and microstructure of nano grain nickel alloy deposit

    International Nuclear Information System (INIS)

    Seo, Moo Hong; Kim, Jung Su; Kim, Seung Ho; Jung, Hyun Kyu; Wyi, Jung Il; Hwang, Woon Suk; Jang, Si Sung; Chun, Byung Sun

    2003-01-01

    In this study, Ni-P layers were electroplated on the surface of stainless steel in order to investigate the effects of an additive and agitation on their mechanical properties and microstructure. The concentration of the additive in the plating solution increased, the pores formed in the layer decreased, while the residual stress developed in the layers during electroplating increased. Agitation of the solution during electroplating was observed to force to increase local pores in the layer which lowers its tensile properties. Grain growth was suppressed due to very fine Ni 3 P precipitates formed at its grain boundaries during heat treatment at 343 .deg. C for 1 hr in air

  17. Mixed 2D molecular systems: Mechanic, thermodynamic and dielectric properties

    Energy Technology Data Exchange (ETDEWEB)

    Beno, Juraj [Department of Physics, Faculty of Electrical Engineering and Information Technology, Slovak University of Technology, Ilkovicova 3, 812 19-SK Bratislava (Slovakia); Weis, Martin [Department of Physics, Faculty of Electrical Engineering and Information Technology, Slovak University of Technology, Ilkovicova 3, 812 19-SK Bratislava (Slovakia)], E-mail: Martin.Weis@stuba.sk; Dobrocka, Edmund [Department of Physics, Faculty of Electrical Engineering and Information Technology, Slovak University of Technology, Ilkovicova 3, 812 19-SK Bratislava (Slovakia); Institute of Electrical Engineering, Slovak Academy of Sciences, Dubravska cesta 9, 841 04-SK Bratislava (Slovakia); Hasko, Daniel [International Laser Centre, Ilkovicova 3, 812 19-SK Bratislava (Slovakia)

    2008-08-15

    Study of Langmuir monolayers consisting of stearic acid (SA) and dipalmitoylphosphatidylcholine (DPPC) molecules was done by surface pressure-area isotherms ({pi}-A), the Maxwell displacement current (MDC) measurement, X-ray reflectivity (XRR) and atomic force microscopy (AFM) to investigate the selected mechanic, thermodynamic and dielectric properties based on orientational structure of monolayers. On the base of {pi}-A isotherms analysis we explain the creation of stable structures and found optimal monolayer composition. The dielectric properties represented by MDC generated monolayers were analyzed in terms of excess dipole moment, proposing the effect of dipole-dipole interaction. XRR and AFM results illustrate deposited film structure and molecular ordering.

  18. Constitutive Modeling of the Mechanical Properties of Optical Fibers

    Science.gov (United States)

    Moeti, L.; Moghazy, S.; Veazie, D.; Cuddihy, E.

    1998-01-01

    Micromechanical modeling of the composite mechanical properties of optical fibers was conducted. Good agreement was obtained between the values of Young's modulus obtained by micromechanics modeling and those determined experimentally for a single mode optical fiber where the wave guide and the jacket are physically coupled. The modeling was also attempted on a polarization-maintaining optical fiber (PANDA) where the wave guide and the jacket are physically decoupled, and found not to applicable since the modeling required perfect bonding at the interface. The modeling utilized constituent physical properties such as the Young's modulus, Poisson's ratio, and shear modulus to establish bounds on the macroscopic behavior of the fiber.

  19. Film Permeability Determination Using Static Permeability Cells

    Science.gov (United States)

    The permeability of tarps to soil fumigant pesticides varies depending on the active ingredient chemical: dimethyl disulfide (DMDS), methyl bromide, chloropicrin, or other. The diffusion rate can be represented by the mass transfer coefficient (MTC).

  20. Effect of Gallic acid on mechanical and water barrier properties of zein-oleic acid composite films.

    Science.gov (United States)

    Masamba, Kingsley; Li, Yue; Hategekimana, Joseph; Liu, Fei; Ma, Jianguo; Zhong, Fang

    2016-05-01

    In this study, the effect of gallic acid on mechanical and water barrier properties of zein-oleic acid 0-4 % composite films was investigated. Molecular weight distribution analysis was carried out to confirm gallic acid induced cross linking through change in molecular weight in fraction containing zein proteins. Results revealed that gallic acid treatment increased tensile strength from 17.9 MPa to 26.0 MPa, decreased water vapour permeability from 0.60 (g mm m(-2) h(-1) kPa(-1)) to 0.41 (g mm m(-2) h(-1) kPa(-1)), increased solubility from 6.3 % to 10.2 % and marginally increased elongation at break from 3.7 % to 4.2 % in zein films only. However, gallic acid treatment in zein-oleic composite films did not significantly influence mechanical and water barrier properties and in most instances irrespective of oleic acid concentration, the properties were negatively affected. Results from scanning electron microscopy showed that both gallic acid treated and untreated zein films and composite films containing 3 % oleic acid had a compact and homogeneous structure while those containing 4 % oleic acid had inhomogeneous structure. The findings have demonstrated that gallic acid treatment can significantly improve mechanical and water barrier properties especially in zein films only as opposed to when used in composite films using zein and oleic acid.

  1. Studying physical properties of deformed intact and fractured rocks by micro-scale hydro-mechanical-seismicity model

    Science.gov (United States)

    Raziperchikolaee, Samin

    The pore pressure variation in an underground formation during hydraulic stimulation of low permeability formations or CO2 sequestration into saline aquifers can induce microseismicity due to fracture generation or pre-existing fracture activation. While the analysis of microseismic data mainly focuses on mapping the location of fractures, the seismic waves generated by the microseismic events also contain information for understanding of fracture mechanisms based on microseismic source analysis. We developed a micro-scale geomechanics, fluid-flow and seismic model that can predict transport and seismic source behavior during rock failure. This model features the incorporation of microseismic source analysis in fractured and intact rock transport properties during possible rock damage and failure. The modeling method considers comprehensive grains and cements interaction through a bonded-particle-model. As a result of grain deformation and microcrack development in the rock sample, forces and displacements in the grains involved in the bond breakage are measured to determine seismic moment tensor. In addition, geometric description of the complex pore structure is regenerated to predict fluid flow behavior of fractured samples. Numerical experiments are conducted for different intact and fractured digital rock samples, representing various mechanical behaviors of rocks and fracture surface properties, to consider their roles on seismic and transport properties of rocks during deformation. Studying rock deformation in detail provides an opportunity to understand the relationship between source mechanism of microseismic events and transport properties of damaged rocks to have a better characterizing of fluid flow behavior in subsurface formations.

  2. Physical and mechanical properties of high manganese non-magnetic steel and its application to various products for commercial use

    International Nuclear Information System (INIS)

    Sasaki, Terufumi; Watanabe, Kenji; Nohara, Kiyohiko; Ono, Yutaka; Kondo, Nobuyuki; Sato, Shuzo.

    1982-01-01

    In order to develop new high manganese non-magnetic steels that can be employed to extensive applications ranging from cryogenic to elevated temperature uses, the effects of C and Mn on their magnetic permeability, thermal expansion coefficient and mechanical properties are investigated. It is found that the relation between thermal expansion coefficient, β, and both C and Mn contents can be expressed by the following linear regression equation: β( x 10 -6 / 0 C) = 17.66 + 3.82 C (%) - 0.22 Mn (%). Good mechanical properties are exhibited in the wide range of Mn contents between 18 % and 30 % at room temperature, while there is a tendency that this optimum range of Mn content is narrowed at cryogenic temperature. Then, H-shapes, round bars and deformed bars are manufactured at the workshops using 5t vacuum melted ingots, aiming to establish the conditions for practical processes for final products and to study such various characteristics of the products as their physical and mechanical properties, machinability and weldability. As a result, it is shown that all of those products have excellent properties as non-magnetic steels. In addition, the manufacturing of non-magnetic pinch rolls attached to the electro-magnetic stirring equipment on the continuous casting machine is described in detail as one of the practical applications of the high Mn non-magnetic steels. (author)

  3. Mass production of bulk artificial nacre with excellent mechanical properties.

    Science.gov (United States)

    Gao, Huai-Ling; Chen, Si-Ming; Mao, Li-Bo; Song, Zhao-Qiang; Yao, Hong-Bin; Cölfen, Helmut; Luo, Xi-Sheng; Zhang, Fu; Pan, Zhao; Meng, Yu-Feng; Ni, Yong; Yu, Shu-Hong

    2017-08-18

    Various methods have been exploited to replicate nacre features into artificial structural materials with impressive structural and mechanical similarity. However, it is still very challenging to produce nacre-mimetics in three-dimensional bulk form, especially for further scale-up. Herein, we demonstrate that large-sized, three-dimensional bulk artificial nacre with comprehensive mimicry of the hierarchical structures and the toughening mechanisms of natural nacre can be facilely fabricated via a bottom-up assembly process based on laminating pre-fabricated two-dimensional nacre-mimetic films. By optimizing the hierarchical architecture from molecular level to macroscopic level, the mechanical performance of the artificial nacre is superior to that of natural nacre and many engineering materials. This bottom-up strategy has no size restriction or fundamental barrier for further scale-up, and can be easily extended to other material systems, opening an avenue for mass production of high-performance bulk nacre-mimetic structural materials in an efficient and cost-effective way for practical applications.Artificial materials that replicate the mechanical properties of nacre represent important structural materials, but are difficult to produce in bulk. Here, the authors exploit the bottom-up assembly of 2D nacre-mimetic films to fabricate 3D bulk artificial nacre with an optimized architecture and excellent mechanical properties.

  4. Metallurgical Mechanisms Controlling Mechanical Properties of Aluminum Alloy 2219 Produced By Electron Beam Freeform Fabrication

    Science.gov (United States)

    Domack, Marcia S.; Taminger, Karen M. B.; Begley, Matthew

    2006-01-01

    The electron beam freeform fabrication (EBF3) layer-additive manufacturing process has been developed to directly fabricate complex geometry components. EBF3 introduces metal wire into a molten pool created on the surface of a substrate by a focused electron beam. Part geometry is achieved by translating the substrate with respect to the beam to build the part one layer at a time. Tensile properties have been demonstrated for electron beam deposited aluminum and titanium alloys that are comparable to wrought products, although the microstructures of the deposits exhibit features more typical of cast material. Understanding the metallurgical mechanisms controlling mechanical properties is essential to maximizing application of the EBF3 process. In the current study, mechanical properties and resulting microstructures were examined for aluminum alloy 2219 fabricated over a range of EBF3 process variables. Material performance was evaluated based on tensile properties and results were compared with properties of Al 2219 wrought products. Unique microstructures were observed within the deposited layers and at interlayer boundaries, which varied within the deposit height due to microstructural evolution associated with the complex thermal history experienced during subsequent layer deposition. Microstructures exhibited irregularly shaped grains, typically with interior dendritic structures, which were described based on overall grain size, morphology, distribution, and dendrite spacing, and were correlated with deposition parameters. Fracture features were compared with microstructural elements to define fracture paths and aid in definition of basic processing-microstructure-property correlations.

  5. Enhancing Microstructure and Mechanical Properties of AZ31-MWCNT Nanocomposites through Mechanical Alloying

    Directory of Open Access Journals (Sweden)

    J. Jayakumar

    2013-01-01

    Full Text Available Multiwall carbon nanotubes (MWCNTs reinforced Mg alloy AZ31 nanocomposites were fabricated by mechanical alloying and powder metallurgy technique. The reinforcement material MWCNTs were blended in three weight fractions (0.33%, 0.66%, and 1% with the matrix material AZ31 (Al-3%, zinc-1% rest Mg and blended through mechanical alloying using a high energy planetary ball mill. Specimens of monolithic AZ31 and AZ31-MWCNT composites were fabricated through powder metallurgy technique. The microstructure, density, hardness, porosity, ductility, and tensile properties of monolithic AZ31 and AZ31-MWCNT nano composites were characterized and compared. The characterization reveals significant reduction in CNT (carbon nanoTube agglomeration and enhancement in microstructure and mechanical properties due to mechanical alloying through ball milling.

  6. Response of mechanical properties of glasses to their chemical, thermal and mechanical histories

    DEFF Research Database (Denmark)

    Yue, Yuanzheng

    , surface, thermal history or excess entropy of the final glass state. Here I review recent progresses in understanding of the responses of mechanical properties of oxide glasses to the compositional variation, thermal history and mechanical deformation. The tensile strength, elastic modulus and hardness...... of glass fibers are dependent on the thermal history (measured as fictive temperature), tension, chemical composition and redox state. However, the fictive temperature affects the hardness of bulk glass in a complicated manner, i.e., the effect does not exhibit a clear regularity in the range...... and micro-cracks occurring during indentation of a glass is discussed briefly. Finally I describe the future perspectives and challenges in understanding responses of mechanical properties of oxide glasses to compositional variation, thermal history and mechanical deformation....

  7. Laser welding of polymers, compatibility and mechanical properties

    DEFF Research Database (Denmark)

    Nielsen, Steen Erik; Strange, Marianne; Kristensen, Jens Klæstrup

    2013-01-01

    for research and development. This paper presents some research results related to laser welding of various polymer materials, including weld compatibility investigations related to the joining of different polymers. Theory for bonding mechanisms, strength development, mechanical properties testing and other......Laser welding of polymers is today a commonly used industrial technology. It has shown obvious advantages compared to e.g. adhesive bonding in terms of higher productivity, better quality and easiness for automation. The ongoing development of lasers tailored for polymer welding in coordination...

  8. Mechanical and vasomotor properties of piglet isolated middle cerebral artery

    DEFF Research Database (Denmark)

    Eriksen, Vibeke R.; Abdolalizadeh, Bahareh; Trautner, Simon

    2017-01-01

    in newborns, is not characterized in piglets’ MCA. Finally, the influence of preterm birth on the dopamine response is not known. The aim of this current was to compare by wire myography the active and passive mechanical characteristics and dopamine concentration–response relations of MCAs isolated from...... to increasing concentrations of dopamine was biphasic, starting with vasodilation in the 1 nmol/L–0.3 μmol/L concentration range followed by vasoconstriction at higher concentrations. The response was very similar between the two groups. In conclusion, the mechanical properties of the MCA as well...

  9. Stretchable polyurethane sponge reinforced magnetorheological material with enhanced mechanical properties

    International Nuclear Information System (INIS)

    Ge, Lin; Xuan, Shouhu; Liao, Guojiang; Yin, Tiantian; Gong, Xinglong

    2015-01-01

    A stretchable magnetorheological material (SMRM) consisting of micro-meter carbonyl iron (CI) particles, low cross-linking polyurethane (PU) polymer and porous PU sponge has been developed. Due to the presence of the PU sponge, the high-performance MR material can be reversibly stretched or bent, just as MR elastomers. When the CI content increases to 80 wt%, the magnetic induced modulus of the MR material can reach as high as 7.34 MPa and the corresponding relative MR effect increases to 820%. A possible strengthening mechanism of the SMRM was proposed. The attractive mechanical properties make the SMRM a promising candidate for future high-performance devices. (technical note)

  10. Influence of porosity on mechanical properties of tetragonal stabilized zirconia

    DEFF Research Database (Denmark)

    Boccaccini, Dino; Frandsen, Henrik Lund; Soprani, Stefano

    2018-01-01

    3YSZ specimens with variable open porosity (1–57%) were fabricated, and the stiffness, strength and fracture properties (fracture toughness and R-curve) were measured to investigate their potential use as support structures for solid oxide fuel or electrolysis cells. The ball-on-ring test was used...... to characterize Young's modulus and Weibull strength. The variation of fracture toughness with porosity was investigated and modelled using the results from fracture mechanical testing. A distinct R-curve behaviour was observed in dense 3YSZ specimens, in samples with a porosity around 15% and in some...... supports for SOFC/SOECs from a mechanical point of view....

  11. Mechanical properties and thermal behaviour of LLDPE/MWNTs nanocomposites

    Directory of Open Access Journals (Sweden)

    Tai Jin-hua

    2012-12-01

    Full Text Available Multi-walled carbon nanotubes (MWNTs were incorporated into a linear low-density polyethylene (LLDPE matrix through using screw extrusion and injection technique. The effect of different weight percent loadings of MWNTs on the morphology, mechanical, and thermal of LLDPE/MWNTs nanocomposite had been investigated. It was found that, at low concentration of MWNTs, it could uniformly disperse into a linear low-density polyethylene matrix and provide LLDPE/MWNTs nanocomposites much improved mechanical properties. Thermal analysis showed that a clear improvement of thermal stability for LLDPE/MWNTs nanocomposites increased with increasing MWNTs content.

  12. Review of research on the mechanical properties of the human tooth

    Science.gov (United States)

    Zhang, Ya-Rong; Du, Wen; Zhou, Xue-Dong; Yu, Hai-Yang

    2014-01-01

    ‘Bronze teeth' reflect the mechanical properties of natural teeth to a certain extent. Their mechanical properties resemble those of a tough metal, and the gradient of these properties lies in the direction from outside to inside. These attributes confer human teeth with effective mastication ability. Understanding the various mechanical properties of human teeth and dental materials is the basis for the development of restorative materials. In this study, the elastic properties, dynamic mechanical properties (visco-elasticity) and fracture mechanical properties of enamel and dentin were reviewed to provide a more thorough understanding of the mechanical properties of human teeth. PMID:24743065

  13. Mechanical properties and impact behavior of a microcellular structural foam

    Directory of Open Access Journals (Sweden)

    M. Avalle

    Full Text Available Structural foams are a relatively new class of materials with peculiar characteristics that make them very attractive in some energy absorption applications. They are currently used for packaging to protect goods from damage during transportation in the case of accidental impacts. Structural foams, in fact, have sufficient mechanical strength even with reduced weight: the balance between the two antagonist requirements demonstrates that these materials are profitable. Structural foams are generally made of microcellular materials, obtained by polymers where voids at the microscopic level are created. Although the processing technologies and some of the material properties, including mechanical, are well known, very little is established for what concerns dynamic impact properties, for the design of energy absorbing components made of microcellular foams. The paper reports a number of experimental results, in different loading conditions and loading speed, which will be a basis for the structural modeling.

  14. Optimising mechanical properties of hot forged nickel superalloy 625 components

    Science.gov (United States)

    Singo, Nthambe; Coles, John; Rosochowska, Malgorzata; Lalvani, Himanshu; Hernandez, Jose; Ion, William

    2018-05-01

    Hot forging and subsequent heat treatment were resulting in substandard mechanical properties of nickel superalloy, Alloy 625, components. The low strength was found to be due to inadequate deformation during forging, excessive grain growth and precipitation of carbides during subsequent heat treatment. Experimentation in a drop forging company and heat treatment facility led to the establishment of optimal parameters to minimise grain size and mitigate the adverse effects of carbide precipitation, leading to successful fulfilment of mechanical property specifications. This was achieved by reducing the number of operations, maximising the extent of deformation by changing the slug dimensions and its orientation in the die, and minimising the time of exposure to elevated temperatures in both the forging and subsequent heat treatment processes to avoid grain growth.

  15. Mechanical Properties of Low Density Alloys at Cryogenic Temperatures

    International Nuclear Information System (INIS)

    Jiao, X. D.; Liu, H. J.; Li, L. F.; Yang, K.

    2006-01-01

    Low-density alloys include aluminum alloys, titanium alloys and magnesium alloys. Aluminum alloys and titanium alloys have been widely investigated and used as structural materials for cryogenic applications because of their light weight and good low-temperature mechanical properties.For aerospace applications, persistent efforts are being devoted to reducing weight and improving performance. Magnesium alloys are the lightest structural alloys among those mentioned above. Therefore, it is necessary to pay attention to magnesium alloys and to investigate their behaviors at cryogenic temperatures. In this paper, we have investigated the mechanical properties and microstructures of some magnesium alloys at cryogenic temperatures. Experimental results on both titanium and magnesium alloys are taken into account in considering these materials for space application

  16. Anisotropic mechanical properties of graphene sheets from molecular dynamics

    International Nuclear Information System (INIS)

    Ni Zhonghua; Bu Hao; Zou Min; Yi Hong; Bi Kedong; Chen Yunfei

    2010-01-01

    Anisotropic mechanical properties are observed for a sheet of graphene along different load directions. The anisotropic mechanical properties are attributed to the hexagonal structure of the unit cells of the graphene. Under the same tensile loads, the edge bonds bear larger load in the longitudinal mode (LM) than in the transverse mode (TM), which causes fracture sooner in LM than in TM. The Young's modulus and the third order elastic modulus for the LM are slightly larger than that for the TM. Simulation also demonstrates that, for both LM and TM, the loading and unloading stress-strain response curves overlap as long as the graphene is unloaded before the fracture point. This confirms that graphene sustains complete elastic and reversible deformation in the elongation process.

  17. A Review of the Mechanical Properties of Concrete Containing Biofillers

    Science.gov (United States)

    Ezdiani Mohamad, Mazizah; Mahmood, Ali A.; Min, Alicia Yik Yee; Khalid, Nur Hafizah A.

    2016-11-01

    Sustainable construction is a rapidly increasing research area. Investigators of all backgrounds are using industrial and agro wastes to replace Portland cement in concrete to reduce greenhouse emissions and the corresponding decline in general health. Many types of wastes have been used as cement replacements in concrete including: fly ash, slag and rice husk ash in addition to others. This study investigates the possibility of producing a sustainable approach to construction through the partial replacement of concrete using biofillers. This will be achieved by studying the physical and mechanical properties of two widely available biological wastes in Malaysia; eggshell and palm oil fuel ash (POFA). The mechanical properties tests that were studied and compared are the compression, tensile and flexural tests.

  18. Investigation of the mechanical and electrical properties of superconducting coils

    International Nuclear Information System (INIS)

    Saito, T.; Yamagiwa, T.; Hara, K.; Kojima, Y.; Hosoyama, K.; Mori, A.; Nojima, K.; Okamoto, Y.; Takabayashi, S.; Tanaka, T.

    1994-01-01

    Measurement of elastic (Young's) modulus of the superconducting coil and electrical punch-through test have been performed at LBL to understand the mechanical and electrical properties of the superconducting coils. The authors have investigated the elastic modulus of the superconducting coils with six kinds of insulators (made with polyimide-fiberglass-epoxy and all polyimide insulation with epoxy/polyimide adhesive) at room and liquid nitrogen temperatures using samples made of 10 stacks of superconducting cables. The samples are cured under varying compression to investigate the curing pressure dependence of Young's modulus of the coils with six kinds of the insulation system. The electrical punch-through test has also performed under compression at room and liquid nitrogen temperatures to investigate electrical integrity of the insulated coils. The tensile strength test of four kinds of polyimide films has been performed at various temperatures (between cryogenic and coil curing temperatures) to understand the mechanical properties of the films

  19. Effects of water infusions on mechanical properties of carboniferous rocks

    Energy Technology Data Exchange (ETDEWEB)

    Vavro, M; Chlebik, J

    1977-01-01

    Method of water infusion is used in the Ostrava-Karvina coal region in Czechoslovakia, where the roof of the extracted coal seam consists of thick rock layers (sandstone, Namurian B series) characterized by high resistance to compression, high coefficient of linear elasticity and high capacity of accumulating energy. When the resistance boundary is crossed and the rocks are disturbed this energy is suddenly released and transferred to the surrounding rock masses, coal seam and support system. On the basis of laboratory experiments the physico-mechanical and energy properties of carboniferous rocks together with calculation of their energy coefficient and other parameters are described and calculated. The results of research and theoretical solutions are presented. Practical use of water infusions to influence mechanical properties of sandstone in the roof of coal seams is described with the example of the Dukla coal mine. (5 refs.) (In Polish)

  20. Biodegradability and mechanical properties of starch films from Andean crops.

    Science.gov (United States)

    Torres, F G; Troncoso, O P; Torres, C; Díaz, D A; Amaya, E

    2011-05-01

    Different Andean crops were used to obtain starches not previously reported in literature as raw material for the production of biodegradable polymers. The twelve starches obtained were used to prepare biodegradable films by casting. Water and glycerol were used as plasticizers. The mechanical properties of the starch based films were assessed by means of tensile tests. Compost tests and FTIR tests were carried out to assess biodegradability of films. The results show that the mechanical properties (UTS, Young's modulus and elongation at break) of starch based films strongly depend on the starch source used for their production. We found that all the starch films prepared biodegrade following a three stage process and that the weight loss rate of all the starch based films tested was higher than the weight loss rate of the cellulose film used as control. Copyright © 2011 Elsevier B.V. All rights reserved.

  1. Microstructure and mechanical properties of selective laser melted magnesium

    International Nuclear Information System (INIS)

    Ng, C.C.; Savalani, M.M.; Lau, M.L.; Man, H.C.

    2011-01-01

    The effects of laser processing parameters on the microstructure and mechanical properties of selective laser-melted magnesium were investigated. The results show that the microstructure characteristics of the laser-melted samples are dependent on the grain size of SLM magnesium. The grains in the molten zone coarsen as the laser energy density increases. In addition, the average hardness values of the molten zone decreases significantly with an increase of the laser energy densities and then decreased slowly at a relatively high laser energy density irrespective of mode of irradiation. The hardness value was obtained from 0.59 to 0.95 GPa and corresponding elastic modulus ranging from 27 to 33 GPa. The present selective laser-melted magnesium parts are promising for biomedical applications since the mechanical properties are more closely matched with human bone than other metallic biomaterials.

  2. Study on Mechanical Properties of Hybrid Fiber Reinforced Concrete

    Science.gov (United States)

    He, Dongqing; Wu, Min; Jie, Pengyu

    2017-12-01

    Several common high elastic modulus fibers (steel fibers, basalt fibers, polyvinyl alcohol fibers) and low elastic modulus fibers (polypropylene fiber) are incorporated into the concrete, and its cube compressive strength, splitting tensile strength and flexural strength are studied. The test result and analysis demonstrate that single fiber and hybrid fiber will improve the integrity of the concrete at failure. The mechanical properties of hybrid steel fiber-polypropylene fiber reinforced concrete are excellent, and the cube compressive strength, splitting tensile strength and flexural strength respectively increase than plain concrete by 6.4%, 3.7%, 11.4%. Doped single basalt fiber or polypropylene fiber and basalt fibers hybrid has little effect on the mechanical properties of concrete. Polyvinyl alcohol fiber and polypropylene fiber hybrid exhibit ‘negative confounding effect’ on concrete, its splitting tensile and flexural strength respectively are reduced by 17.8% and 12.9% than the single-doped polyvinyl alcohol fiber concrete.

  3. Statistical-mechanical theory of the overall magnetic properties of mesocrystals.

    Science.gov (United States)

    Huang, J P

    2004-10-01

    The mesocrystal showing both electrorheological and magnetorheological effects is called electro-magnetorheological (EMR) solids. Prediction of the overall magnetic properties of the EMR solids is a challenging task due to the coexistence of the uniaxially anisotropic behavior and structural transition as well as long-range interaction between the suspended particles. To consider the uniaxial anisotropy effect, we present an anisotropic Kirkwood-Fröhlich equation for calculating the effective permeabilities by adopting an explicit characteristic spheroid rather than a characteristic sphere used in the derivation of the usual Kirkwood-Fröhlich equation. Further, by applying an Ewald-Kornfeld formulation we are able to investigate the effective permeability by including the structural transition and long-range interaction explicitly. Our theory can reduce to the usual Kirkwood-Fröhlich equation and Onsager equation naturally. To this end, the numerical simulation shows the validity of monitoring the structure of EMR solids by detecting their effective permeabilities.

  4. Microstructure and mechanical properties of carbon fibre-reinforced ...

    Indian Academy of Sciences (India)

    2018-05-17

    May 17, 2018 ... was focussed on the characteristics of sol and the mechanical properties and high-temperature resistance of ... The reinforcement was 3D carbon fibre (T300 3k, ex-PAN ... where f (a/H) = 2.9(a/H)1/2−4.6(a/H)3/2+21.8(a/H)5/2.

  5. Microstructure and mechanical properties of carbon fiber reinforced ...

    Indian Academy of Sciences (India)

    68

    Alumina; composites; carbon fiber reinforcement; sol; mechanical properties. 1. Introduction ... The reinforcement was 3D carbon fiber (T300 3k, ex-PAN carbon fiber ... where f(a/H) = 2.9(a/H)1/2 – 4.6(a/H)3/2 + 21.8(a/H)5/2. – 37.6(a/H)7/2 + ...

  6. Some physical and mechanical properties of palm kernel shell (PKS ...

    African Journals Online (AJOL)

    In this study, some of the mechanical and physical properties of palm kernel shells (PKS) were evaluated. These are moisture content, 7.8325 ± 0.6672%; true density, 1.254 ± 5.292 x 10-3 g/cm3; bulk density, 1.1248g/cm3; mean rupture force along width, and thickness were 3174.52 ± 270.70N and 2806.94 ± 498.45N for ...

  7. Influence of tempering on mechanical properties of ferritic martensitic steels

    International Nuclear Information System (INIS)

    Chun, Y. B.; Han, C. H.; Choi, B. K.; Lee, D. W.; Kim, T. K.; Jeong, Y. H.; Cho, S.

    2012-01-01

    In the mid-1980s research programs for development of low activation materials began. This is based on the US Nuclear Regulatory Commission Guidelines (10CFR part 61) that were developed to reduce long-lived radioactive isotopes, which allows nuclear reactor waste to be disposed of by shallow land burial when removed from service. Development of low activation materials is also key issue in nuclear fusion systems, as the structural components can became radioactive due to nuclear transmutation caused by exposure to high dose neutron irradiation. Reduced-activation ferritic martensitic (RAFM) steels have been developed in the leading countries in nuclear fusion technology, and are now being considered as primary candidate material for the test blanket module (TBM) in the international thermonuclear experiment reactor (ITER). RAFM steels developed so far (e.g., EUROFER 97 and F82H) meet the requirement for structural application in the ITER. However, if such alloys are used in the DEMO or commercial fusion reactor is still unclear, as the reactors are designed to operate under much severe conditions (i.e., higher outlet coolant temperature and neutron fluences). Such harsh operating conditions lead to development of RAFM steels with better creep and irradiation resistances. Mechanical properties of RAFM steels are strongly affected by microstructural features including the distribution, size and type of precipitates, dislocation density and grain size. For a given composition, such microstructural characteristics are determined mainly by thermo-mechanical process employed to fabricate the final product, and accordingly a final heat treatment, i.e., tempering is the key step to control the microstructure and mechanical properties. In the present work, we investigated mechanical properties of the RAFM steels with a particular attention being paid to effects of tempering on impact and creep properties

  8. Effect of precipitates on mechanical properties of AA2195

    International Nuclear Information System (INIS)

    Kim, Jae-Hee; Jeun, Jeong-Hoon; Chun, Hyun-Jin; Lee, Ye Rim; Yoo, Joon-Tae; Yoon, Jong-Hoon; Lee, Ho-Sung

    2016-01-01

    Addition of 1–4 wt.% lithium into a conventional Al–Cu–Mg alloy allows lower density and higher mechanical properties, which are attractive for aerospace applications. In this study, fundamental investigations including phase and microstructure evolution, resulting in strengthening, of the AA2195 are conducted to observe a possibility of production with commercial level. Precipitation sequence and kinetics during post-annealing were evaluated with variations of temperature and holding time. Microstructures revealed formation and evolution in representative precipitates including θ (Al_2Cu), ß′ (Al_3Zr), and T (Al_xLi_yCu) series. Aluminum alloys have low hardness, modulus, and strength before aging, but precipitates such as θ′ (Al_2Cu), ß′ (Al_3Zr), and T_1 (Al_2LiCu) show enhanced mechanical properties of AA2195 tempered because of their interaction with dislocation. However, longer holding time and higher annealing temperature result in significant decreases in mechanical properties due to the presence of incoherent precipitates (θ phase) and coarsening of the precipitates via grain-boundary diffusion. In the current study, the tensile strength of 560 MPa was obtained with post-heat treatment without work hardening. This value has never been achieved in other studies. The maximum strength was reported as 500 MPa without a work hardening process. - Highlights: • A relationship between microstructure and mechanical properties to post annealing AA2195. • A formation and dissolution of the precipitates were observed for various treatment. • An optimum post-annealing condition was obtained.

  9. Experimental evaluation of mechanical properties of softwood using acoustic methods

    Czech Academy of Sciences Publication Activity Database

    Tippner, J.; Hrivnák, J.; Kloiber, Michal

    2016-01-01

    Roč. 11, č. 1 (2016), s. 503-518 ISSN 1930-2126 R&D Projects: GA MK(CZ) DF11P01OVV001 Keywords : non destructive testing * Norway spruce * Scots pine * Silver fir * sound speed * strength * stress wave Subject RIV: AL - Art, Architecture, Cultural Heritage Impact factor: 1.321, year: 2016 http://ojs.cnr.ncsu.edu/index.php/BioRes/article/view/BioRes_11_1_503_Tippner_Mechanical_Properties_Acoustic_Methods/4018

  10. Nondestructive measurement of esophageal biaxial mechanical properties utilizing sonometry

    Science.gov (United States)

    Aho, Johnathon M.; Qiang, Bo; Wigle, Dennis A.; Tschumperlin, Daniel J.; Urban, Matthew W.

    2016-07-01

    Malignant esophageal pathology typically requires resection of the esophagus and reconstruction to restore foregut continuity. Reconstruction options are limited and morbid. The esophagus represents a useful target for tissue engineering strategies based on relative simplicity in comparison to other organs. The ideal tissue engineered conduit would have sufficient and ideally matched mechanical tolerances to native esophageal tissue. Current methods for mechanical testing of esophageal tissues both in vivo and ex vivo are typically destructive, alter tissue conformation, ignore anisotropy, or are not able to be performed in fluid media. The aim of this study was to investigate biomechanical properties of swine esophageal tissues through nondestructive testing utilizing sonometry ex vivo. This method allows for biomechanical determination of tissue properties, particularly longitudinal and circumferential moduli and strain energy functions. The relative contribution of mucosal-submucosal layers and muscular layers are compared to composite esophagi. Swine thoracic esophageal tissues (n  =  15) were tested by pressure loading using a continuous pressure pump system to generate stress. Preconditioning of tissue was performed by pressure loading with the pump system and pre-straining the tissue to in vivo length before data was recorded. Sonometry using piezocrystals was utilized to determine longitudinal and circumferential strain on five composite esophagi. Similarly, five mucosa-submucosal and five muscular layers from thoracic esophagi were tested independently. This work on esophageal tissues is consistent with reported uniaxial and biaxial mechanical testing and reported results using strain energy theory and also provides high resolution displacements, preserves native architectural structure and allows assessment of biomechanical properties in fluid media. This method may be of use to characterize mechanical properties of tissue engineered esophageal

  11. Theoretical methods and models for mechanical properties of soft biomaterials

    Directory of Open Access Journals (Sweden)

    Zhonggang Feng

    2017-06-01

    Full Text Available We review the most commonly used theoretical methods and models for the mechanical properties of soft biomaterials, which include phenomenological hyperelastic and viscoelastic models, structural biphasic and network models, and the structural alteration theory. We emphasize basic concepts and recent developments. In consideration of the current progress and needs of mechanobiology, we introduce methods and models for tackling micromechanical problems and their applications to cell biology. Finally, the challenges and perspectives in this field are discussed.

  12. Effect of precipitates on mechanical properties of AA2195

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Jae-Hee [Launcher Structure and Materials Team, Korea Aerospace Research Institute, Daejeon (Korea, Republic of); Jeun, Jeong-Hoon [Department of Materials Science and Engineering, Seoul National University, Seoul (Korea, Republic of); Chun, Hyun-Jin [Southeast University, Nanjing (China); Lee, Ye Rim [Department of Aerospace System Engineering, University of Science & Technology, Daejeon (Korea, Republic of); Yoo, Joon-Tae [Launcher Structure and Materials Team, Korea Aerospace Research Institute, Daejeon (Korea, Republic of); Yoon, Jong-Hoon [Launcher Structure and Materials Team, Korea Aerospace Research Institute, Daejeon (Korea, Republic of); Department of Aerospace System Engineering, University of Science & Technology, Daejeon (Korea, Republic of); Lee, Ho-Sung, E-mail: hslee@kari.re.kr [Launcher Structure and Materials Team, Korea Aerospace Research Institute, Daejeon (Korea, Republic of); Department of Aerospace System Engineering, University of Science & Technology, Daejeon (Korea, Republic of)

    2016-06-05

    Addition of 1–4 wt.% lithium into a conventional Al–Cu–Mg alloy allows lower density and higher mechanical properties, which are attractive for aerospace applications. In this study, fundamental investigations including phase and microstructure evolution, resulting in strengthening, of the AA2195 are conducted to observe a possibility of production with commercial level. Precipitation sequence and kinetics during post-annealing were evaluated with variations of temperature and holding time. Microstructures revealed formation and evolution in representative precipitates including θ (Al{sub 2}Cu), ß′ (Al{sub 3}Zr), and T (Al{sub x}Li{sub y}Cu) series. Aluminum alloys have low hardness, modulus, and strength before aging, but precipitates such as θ′ (Al{sub 2}Cu), ß′ (Al{sub 3}Zr), and T{sub 1} (Al{sub 2}LiCu) show enhanced mechanical properties of AA2195 tempered because of their interaction with dislocation. However, longer holding time and higher annealing temperature result in significant decreases in mechanical properties due to the presence of incoherent precipitates (θ phase) and coarsening of the precipitates via grain-boundary diffusion. In the current study, the tensile strength of 560 MPa was obtained with post-heat treatment without work hardening. This value has never been achieved in other studies. The maximum strength was reported as 500 MPa without a work hardening process. - Highlights: • A relationship between microstructure and mechanical properties to post annealing AA2195. • A formation and dissolution of the precipitates were observed for various treatment. • An optimum post-annealing condition was obtained.

  13. Nanoscaled Mechanical Properties of Cement Composites Reinforced with Carbon Nanofibers

    OpenAIRE

    Barbhuiya, Salim; Chow, PengLoy

    2017-01-01

    This paper reports the effects of carbon nanofibers (CNFs) on nanoscaled mechanical properties of cement composites. CNFs were added to cement composites at the filler loading of 0.2 wt % (by wt. of cement). Micrographs based on scanning electron microscopy (SEM) show that CNFs are capable of forming strong interfacial bonding with cement matrices. Experimental results using nanoindentation reveal that the addition of CNFs in cement composites increases the proportions of high-density calcium...

  14. Simulative calculation of bromo-polystyrene mechanical properties

    CERN Document Server

    Wang Chao; Tang Yong Jian

    2002-01-01

    The non-crystal model of polystyrene and bromo-polystyrene was established with the help of simulative software in the computer. DREIDING was chosen as force field and its parameters is modified according to the published data. Based on the calculation results and other published data the mechanism properties of polystyrene and bromo-polystyrene, such as bulk module, Yong's module and Poisson's ratios, were discussed

  15. Mechanical properties of green composites based on thermoplastic starch

    Science.gov (United States)

    Fornes, F.; Sánchez-Nácher, L.; Fenollar, O.; Boronat, T.; Garcia-Sanoguera, D.

    2010-06-01

    The present work is focused on study of "green composites" elaborated from thermoplastic starch (TPS) as polymer matrix and a fiber from natural origin (rush) as reinforced fiber. The effect of the fiber content has been studied by means of the mechanical properties. The composite resulting presents a lack of interaction between matrix and fiber that represents a performance decrease. However the biodegradability behavior of the resulting composite raise this composite as useful an industrial level.

  16. Mechanical and thermophysical properties of hot-pressed SYNROC B

    International Nuclear Information System (INIS)

    Hoenig, C.L.; Newkirk, H.W.; Otto, R.A.; Brady, R.L.; Brown, A.E.; Ulrich, A.R.; Lum, R.C.

    1981-01-01

    The optimal SYNROC compositons for use with commercial waste are reviewed. Large amounts of powder (about 2.5 kg) were prepared by convention al ceramic operations to test the SYNROC concept on a processing scale. Samples, 15.2 cm in diameter, were hot pressed in graphite, and representative samples were cut for microstructural evaluations. Measured mechanical and thermophysical properties did not vary significantly as a function of sample location and were typical of titanate ceramic materials

  17. High-Mn steel weldment mechanical properties at 4 K

    International Nuclear Information System (INIS)

    Chan, J.W.; Sunwoo, A.J.; Morris, J.W. Jr.

    1988-06-01

    Advanced high-field superconducting magnets of the next generation of magnetic confinement fusion devices will require structural alloys with high yield strength and high toughness at cryogenic temperatures. Commercially available alloys used in the current generation of magnets, such as 300 series stainless steels, do not have the required properties. N-strengthened, high-Mn alloys meet base plate requirements in the as-rolled condition. However, the property changes associated with weld microstructural and chemical changes in these alloys have not been well characterized. In this work welding induced cryogenic mechanical property changes of an 18Mn-16Cr-5Ni-0.2N alloy are correlated with as-solidified weld microstructures and chemistries. 30 refs., 12 figs., 3 tabs

  18. Microstructure and Mechanical Properties of Aligned Natural Fibre Composites

    DEFF Research Database (Denmark)

    Rask, Morten

    properties (stiffness-to-density ratio). The perspective of using natural fibres is to have a sustainable, biodegradable, CO2-neutral alternative to glass fibres. However, so far, it has not been possible to take full advantage of the natural fibre properties when using them for composite applications....... Several challenges have to be addressed and solved, many of which pertain to the fact that the fibres are sourced from a natural resource: 1) Inconsistent properties, depending on plant species, growth and harvest conditions, and fibre extraction techniques. 2) Strength values of composites are lower than...... microscopy during tensile tests of small composite specimens. With this technique, 3D images can be obtained with spatial resolution mechanisms have been identified: (i) Interface...

  19. Protocol dependence of mechanical properties in granular systems.

    Science.gov (United States)

    Inagaki, S; Otsuki, M; Sasa, S

    2011-11-01

    We study the protocol dependence of the mechanical properties of granular media by means of computer simulations. We control a protocol of realizing disk packings in a systematic manner. In 2D, by keeping material properties of the constituents identical, we carry out compaction with various strain rates. The disk packings exhibit the strain rate dependence of the critical packing fraction above which the pressure becomes non-zero. The observed behavior contrasts with the well-studied jamming transitions for frictionless disk packings. We also observe that the elastic moduli of the disk packings depend on the strain rate logarithmically. Our results suggest that there exists a time-dependent state variable to describe macroscopic material properties of disk packings, which depend on its protocol.

  20. A comparison of mechanical properties of some foams and honeycombs

    Science.gov (United States)

    Bhat, Balakrishna T.; Wang, T. G.

    1990-01-01

    A comparative study is conducted of the mechanical properties of foam-core and honeycomb-core sandwich panels, using a normalizing procedure based on common properties of cellular solids and related properties of dense solids. Seven different honeycombs and closed-foam cells are discussed; of these, three are commercial Al alloy honeycombs, one is an Al-alloy foam, and two are polymeric foams. It is concluded that ideal, closed-cell foams may furnish compressive strengths which while isotropic can be fully comparable to the compressive strengths of honeycombs in the thickness direction. The shear strength of ideal closed-cell foams may be superior to the shear strength of honeycombs.