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Sample records for resulting mechanical properties

  1. Mechanical properties testing and results for thermal barrier coatings

    Energy Technology Data Exchange (ETDEWEB)

    Cruse, T.A.; Johnsen, B.P.; Nagy, A.

    1995-10-01

    The paper reports on several years of mechanical testing of thermal barrier coatings. The test results were generated to support the development of durability models for the coatings in heat engine applications. The test data that are reviewed include modulus, static strength, and fatigue strength data. The test methods and results are discussed, along with the significant difficulties inherent in mechanical testing of thermal barrier coating materials. The materials include 7 percent wt. and 8 percent wt. yttria, partially stabilized zirconia as well as a cermet material. Both low pressure plasma spray and electron-beam physical vapor deposited coatings were tested. The data indicate the basic trends in the mechanical properties of the coatings over a wide range of isothermal conditions. Some of the trends are correlated with material density.

  2. Mechanical properties testing and results for thermal barrier coatings

    Science.gov (United States)

    Cruse, Thomas A.; Johnsen, B. P.; Nagy, Andrew

    1995-01-01

    The paper reports on several years of mechanical testing of thermal barrier coatings. The test results were generated to support the development of durability models for the coatings in heat engine applications. The test data that are reviewed include modulus, static strength, and fatigue strength data. The test methods and results are discussed, along with the significant difficulties inherent in mechanical testing of thermal barrier coating materials. The materials include 7 percent wt. and 8 percent wt. yttria, partially stabilized zirconia as well as a cermet material. Both low pressure plasma spray and electron-beam physical vapor deposited coatings were tested. The data indicate the basic trends in the mechanical properties of the coatings over a wide range of isothermal conditions. Some of the trends are correlated with material density.

  3. Specialization of tendon mechanical properties results from interfascicular differences

    Science.gov (United States)

    Thorpe, Chavaunne T.; Udeze, Chineye P.; Birch, Helen L.; Clegg, Peter D.; Screen, Hazel R. C.

    2012-01-01

    Tendons transfer force from muscle to bone. Specific tendons, including the equine superficial digital flexor tendon (SDFT), also store and return energy. For efficient function, energy-storing tendons need to be more extensible than positional tendons such as the common digital extensor tendon (CDET), and when tested in vitro have a lower modulus and failure stress, but a higher failure strain. It is not known how differences in matrix organization contribute to distinct mechanical properties in functionally different tendons. We investigated the properties of whole tendons, tendon fascicles and the fascicular interface in the high-strain energy-storing SDFT and low-strain positional CDET. Fascicles failed at lower stresses and strains than tendons. The SDFT was more extensible than the CDET, but SDFT fascicles failed at lower strains than CDET fascicles, resulting in large differences between tendon and fascicle failure strain in the SDFT. At physiological loads, the stiffness at the fascicular interface was lower in the SDFT samples, enabling a greater fascicle sliding that could account for differences in tendon and fascicle failure strain. Sliding between fascicles prior to fascicle extension in the SDFT may allow the large extensions required in energy-storing tendons while protecting fascicles from damage. PMID:22764132

  4. Specialization of tendon mechanical properties results from interfascicular differences.

    Science.gov (United States)

    Thorpe, Chavaunne T; Udeze, Chineye P; Birch, Helen L; Clegg, Peter D; Screen, Hazel R C

    2012-11-07

    Tendons transfer force from muscle to bone. Specific tendons, including the equine superficial digital flexor tendon (SDFT), also store and return energy. For efficient function, energy-storing tendons need to be more extensible than positional tendons such as the common digital extensor tendon (CDET), and when tested in vitro have a lower modulus and failure stress, but a higher failure strain. It is not known how differences in matrix organization contribute to distinct mechanical properties in functionally different tendons. We investigated the properties of whole tendons, tendon fascicles and the fascicular interface in the high-strain energy-storing SDFT and low-strain positional CDET. Fascicles failed at lower stresses and strains than tendons. The SDFT was more extensible than the CDET, but SDFT fascicles failed at lower strains than CDET fascicles, resulting in large differences between tendon and fascicle failure strain in the SDFT. At physiological loads, the stiffness at the fascicular interface was lower in the SDFT samples, enabling a greater fascicle sliding that could account for differences in tendon and fascicle failure strain. Sliding between fascicles prior to fascicle extension in the SDFT may allow the large extensions required in energy-storing tendons while protecting fascicles from damage.

  5. Determination of mechanical properties from depth-sensing indentation data and results of finite element modeling

    Science.gov (United States)

    Isaenkova, M. G.; Perlovich, Yu A.; Krymskaya, O. A.; Zhuk, D. I.

    2016-04-01

    3D finite element model of indentation process with Berkovich tip was created. Using this model with different type of test materials, several series of calculations were made. These calculations lead to determination of material behavior features during indentation. Relations between material properties and its behavior during instrumented indentation were used for construction of dimensionless functions required for development the calculation algorithm, suitable to determine mechanical properties of materials by results of the depth-sensing indentation. Results of mechanical properties determination using elaborated algorithm for AISI 1020 steel grade were compared to properties obtained with standard compression tests. These two results differ by less than 10% for yield stress that evidence of a good accuracy of the proposed technique.

  6. The effect of glass synthesis route on mechanical and physical properties of resultant glass ionomer cements.

    Science.gov (United States)

    Wren, A; Clarkin, O M; Laffir, F R; Ohtsuki, C; Kim, I Y; Towler, M R

    2009-10-01

    Glass ionomer cements (GICs) have potential orthopaedic applications. Solgel processing is reported as having advantages over the traditional melt-quench route for synthesizing the glass phase of GICs, including far lower processing temperatures and higher levels of glass purity and homogeneity. This work investigates a novel glass formulation, BT 101 (0.48 SiO(2)-0.36 ZnO-0.12 CaO-0.04 SrO) produced by both the melt-quench and the solgel route. The glass phase was characterised by X-ray diffraction (XRD) to determine whether the material was amorphous and differential thermal analysis (DTA) to measure the glass transition temperature (T (g)). Particle size analysis (PSA) was used to determine the mean particle size and X-ray photoelectron spectroscopy (XPS) was used to investigate the structure and composition of the glass. Both glasses, the melt-quench BT 101 and the solgel BT 101, were mixed with 50 wt% polyacrylic acid (M (w), 80,800) and water to form a GIC and the working time (T (w)) and the setting time (T (s)) of the resultant cements were then determined. The cement based on the solgel glass had a longer T (w) (78 s) as compared to the cement based on the melt derived glass (19 s). T (s) was also much longer for the cement based on the solgel (1,644 s) glass than for the cement based on the melt-derived glass (25 s). The cements based on the melt derived glass produced higher strengths in both compression (sigma(c)) and biaxial flexure (sigma(f)), where the highest strength was found to be 63 MPa in compression, at both 1 and 7 days. The differences in setting and mechanical properties can be associated to structural differences within the glass as determined by XPS which revealed the absence of Ca in the solgel system and a much greater concentration of bridging oxygens (BO) as compared to the melt-derived system.

  7. Thermo-Hydro-Mechanical properties of MX-80. Results from advanced laboratory tests

    Energy Technology Data Exchange (ETDEWEB)

    Dueck, Ann; Nilsson, Ulf (Clay Technology AB, Lund (Sweden))

    2010-12-15

    General Highly compacted bentonite is proposed as the buffer material in the Swedish concept for disposal of nuclear waste. The saturated homogenized bentonite is expected to fully act as a buffer material between the waste canister and the surrounding bedrock. Material models describing the thermo-hydro-mechanical (THM) behaviour of the buffer material have been created with the purpose to simulate and predict the behaviour in a repository both before and after water saturation. The material models of water saturated and water unsaturated buffer material are complicated and contain a number of parameters that need to be determined. The present report is a compilation of results concerning thermo-hydro-mechanical laboratory tests on saturated and unsaturated buffer material. The main purpose of the report is to supply modelling groups with available results for improving models and determine parameters that can be used for the THM modelling of the behaviour of the buffer.Retention curves The relation between water content and relative humidity has been determined in a number of test series for some specific conditions, e.g. different initial water contents. Two methods have been used; the sorption balance method and a method with jars as desiccators. The majority of the results were derived from tests where RH was controlled and the response of the bentonite samples was measured. The results are given as water content versus relative humidity in diagrams and in tabular form. Volume change The volume change of water unsaturated bentonite specimens has been investigated by compression tests and swelling/shrinkage tests for some specific stress and moisture paths. The constant relative humidity was generated by the vapour equilibrium technique combined with an air circulation system. Measured stresses, deformation and relative humidity are presented versus time in diagrams and the final values at different stages are also presented in tabular form. Moisture transport

  8. Mechanical Properties of Soft Tailings from a Swedish Tailings Impoundment:Results from Direct Shear Tests

    OpenAIRE

    Bhanbhro, Riaz; Knutsson, Roger; Edeskär, Tommy; Knutsson, Sven

    2014-01-01

    The shear strength of tailings can vary depending upon the type of ore and method of construction. Tailings dams may possess loose layers in subsequent layers, which may have low shear strength. Since the tailings dams are made-up to last for longer times, the strength parameters and material behaviors are essential to understand, especially potential for static liquefaction in loose layers. This article presents the results from direct shear tests performed on samples from loose layer of a t...

  9. Mechanical Properties of Transcription

    Science.gov (United States)

    Sevier, Stuart A.; Levine, Herbert

    2017-06-01

    The mechanical properties of transcription have recently been shown to play a central role in gene expression. However, a full physical characterization of this central biological process is lacking. In this Letter, we introduce a simple description of the basic physical elements of transcription where RNA elongation, RNA polymerase rotation, and DNA supercoiling are coupled. The resulting framework describes the relative amount of RNA polymerase rotation and DNA supercoiling that occurs during RNA elongation. Asymptotic behavior is derived and can be used to experimentally extract unknown mechanical parameters of transcription. Mechanical limits to transcription are incorporated through the addition of a DNA supercoiling-dependent RNA polymerase velocity. This addition can lead to transcriptional stalling and resulting implications for gene expression, chromatin structure and genome organization are discussed.

  10. Mechanical properties of viruses.

    Science.gov (United States)

    de Pablo, Pedro J; Mateu, Mauricio G

    2013-01-01

    Structural biology techniques have greatly contributed to unveil the relationships between structure, properties and functions of viruses. In recent years, classic structural approaches are being complemented by single-molecule techniques such as atomic force microscopy and optical tweezers to study physical properties and functions of viral particles that are not accessible to classic structural techniques. Among these features are mechanical properties such as stiffness, intrinsic elasticity, tensile strength and material fatigue. The field of virus mechanics is contributing to materials science by investigating some physical parameters of "soft" biological matter and biological nano-objects. Virus mechanics studies are also starting to unveil the biological implications of physical properties of viruses. Growing evidence indicate that viruses are subjected to internal and external forces, and that they may have adapted to withstand and even use those forces. This chapter describes what is known on the mechanical properties of virus particles, their structural determinants, and possible biological implications, of which several examples are provided.

  11. Long durations of immobilization in the rat result in enhanced mechanical properties of the healing supraspinatus tendon insertion site.

    Science.gov (United States)

    Gimbel, J A; Van Kleunen, J P; Williams, G R; Thomopoulos, S; Soslowsky, L J

    2007-06-01

    Rotator cuff tears frequently occur and can lead to pain and decreased shoulder function. Repair of the torn tendon back to bone is often successful in relieving pain, but failure of the repair commonly occurs. Post-operative activity level is an important treatment component that has received minimal attention for the shoulder, but may have the potential to enhance tendon to bone healing. The objective of this study was to investigate the effect of short and long durations of various activity levels on the healing supraspinatus tendon to bone insertion site. Rotator cuff tears were surgically created in Sprague-Dawley rats by detaching the supraspinatus tendon from its insertion on the humerus and these tears were immediately repaired back to the insertion site. The post-operative activity level was controlled through shoulder immobilization (IM), cage activity (CA), or moderate exercise (EX) for durations of 4 or 16 weeks. The healing tissue was evaluated utilizing biomechanical testing and a quantitative polarized light microscopy method. We found that activity level had no effect on the elastic properties (stiffness, modulus) of the insertion site at four weeks post injury and repair, and a decreased activity level had a positive effect on these properties at 16 weeks (IM>CA=EX). Furthermore, a decreased activity level had the greatest positive effect on these properties over time (IM>CA=EX). The angular deviation of the collagen, a measure of disorganization, was decreased with a decrease in activity level at 4 weeks (IMtendon to bone healing, which progresses by first increasing the organization of the collagen and then increasing the mechanical properties. Future studies in this area will investigate the effect of passive motion and remobilization on both tendon to bone healing and shoulder function.

  12. Silicone rubbers for dielectric elastomers with improved dielectric and mechanical properties as a result of substituting silica with titanium dioxide

    DEFF Research Database (Denmark)

    Yu, Liyun; Skov, Anne Ladegaard

    2016-01-01

    One prominent method of modifying the properties of dielectric elastomers (DEs) is by adding suitable metal oxide fillers. However, almost all commercially available silicone elastomers are already heavily filled with silica to reinforce the otherwise rather weak silicone network and the resulting...... metal oxide filled elastomer may contain too much filler. We therefore explore the replacement of silica with titanium dioxide to ensure a relatively low concentration of filler. Liquid silicone rubber (LSR) has relatively low viscosity, which is favorable for loading inorganic fillers. In the present...... study, four commercial LSRs with varying loadings of silica and one benchmark room-temperature vulcanizable rubber (RTV) were investigated. The resulting elastomers were evaluated with respect to their dielectric permittivity, tear and tensile strengths, electrical breakdown, thermal stability...

  13. Silicone rubbers for dielectric elastomers with improved dielectric and mechanical properties as a result of substituting silica with titanium dioxide

    Directory of Open Access Journals (Sweden)

    Liyun Yu

    2015-10-01

    Full Text Available One prominent method of modifying the properties of dielectric elastomers (DEs is by adding suitable metal oxide fillers. However, almost all commercially available silicone elastomers are already heavily filled with silica to reinforce the otherwise rather weak silicone network and the resulting metal oxide filled elastomer may contain too much filler. We therefore explore the replacement of silica with titanium dioxide to ensure a relatively low concentration of filler. Liquid silicone rubber (LSR has relatively low viscosity, which is favorable for loading inorganic fillers. In the present study, four commercial LSRs with varying loadings of silica and one benchmark room-temperature vulcanizable rubber (RTV were investigated. The resulting elastomers were evaluated with respect to their dielectric permittivity, tear and tensile strengths, electrical breakdown, thermal stability and dynamic viscosity. Filled silicone elastomers with high loadings of nano-sized titanium dioxide (TiO2 particles were also studied. The best overall performing formulation had 35 wt.% TiO2 nanoparticles in the POWERSIL® XLR LSR, where the excellent ensemble of relative dielectric permittivity of 4.9 at 0.1 Hz, breakdown strength of 160 V µm−1, tear strength of 5.3 MPa, elongation at break of 190%, a Young’s modulus of 0.85 MPa and a 10% strain response (simple tension in a 50 V μm−1 electric field was obtained.

  14. Mechanical Properties of Cells

    Science.gov (United States)

    Bradley, Robert; Becerril, Joseph; Jeevarajan, Anthony

    2007-01-01

    Many physiologic and pathologic processes alter the biomechanical properties of the tissue they affect, and these changes may be manifest at the single cell level. The normal and abnormal mechanical properties of a given cell type can be established with the aid of an atomic force microscope (AFM), nonetheless, consistency in the area of the tip has been a mayor limitation of using the AFM for quantitative measurements of mechanical properties. This project attempts to overcome this limitation by using materials with a known elastic modulus, which resembles the one of the cell, to create force-deformation curves to calculate the area of indentation by means of Hooke s Law (sigma = E(epsilon)), which states that stress (sigma) is proportional to the strain (epsilon) where the constant of proportionality, E, is called the Young s modulus, also referred as the elastic modulus. Hook s Law can be rearranged to find the area of indentation (Area= Force/ E(epsilon)), where the indentation force is defined by the means of the added mass spring calibration method.

  15. Mechanical Properties of Cells

    Science.gov (United States)

    Bradley, Robert; Becerril, Joseph; Jeevarajan, Anthony

    2007-01-01

    Many physiologic and pathologic processes alter the biomechanical properties of the tissue they affect, and these changes may be manifest at the single cell level. The normal and abnormal mechanical properties of a given cell type can be established with the aid of an atomic force microscope (AFM), nonetheless, consistency in the area of the tip has been a mayor limitation of using the AFM for quantitative measurements of mechanical properties. This project attempts to overcome this limitation by using materials with a known elastic modulus, which resembles the one of the cell, to create force-deformation curves to calculate the area of indentation by means of Hooke s Law (sigma = E(epsilon)), which states that stress (sigma) is proportional to the strain (epsilon) where the constant of proportionality, E, is called the Young s modulus, also referred as the elastic modulus. Hook s Law can be rearranged to find the area of indentation (Area= Force/ E(epsilon)), where the indentation force is defined by the means of the added mass spring calibration method.

  16. Storage of solid propellants in a dry environment. [mechanical properties resulting from long term exposure to aerospace environments

    Science.gov (United States)

    Udlock, D. E.

    1978-01-01

    Storage of solid propellants in either a dry or a vacuum environment causes a significantly greater increase in the propellants' modulus and maximum tensile strength than does ambient storage. It is postulated that these physical property changes can be attributed to the effect trace amount of moisture has on the bond between the propellants' binder and oxidizer.

  17. Mechanical Properties of Flexographic Prints

    Directory of Open Access Journals (Sweden)

    Simona Grigaliūnienė

    2014-02-01

    Full Text Available Mechanical properties of paper and flexographic prints madewith different anilox rollers were investigated experimentally.Flexographic prints roughness, breaking force and folding resistancevalues were determined. The results showed that foldingresistance is bigger for machine direction prints than for crossmachine direction prints. Flexographic prints on cardboardsfolding resistance values are different for machine direction andcross machine direction. It was determined that roughness offlexographic prints increases with the amount of ink on aniloxroller. Results were explained by the ink water influence.

  18. Modeling of Developing Inhomogeneities in the Ferrite Microstructure and Resulting Mechanical Properties Induced by Deformation in the Two-Phase Region

    Energy Technology Data Exchange (ETDEWEB)

    Majta, J; Zurek, A.K.; Pietrzyk, M.

    1999-07-13

    The differences in microstructure development of hot deformed steels in the austenite and two-phase region have been effectively described using an integrated computer modeling process. In general, the complete model presented here takes into account kinetics of recrystallization, precipitation, phase transformation, recrystallized austenite grain size, ferrite grain size, and the resulting mechanical properties. The transformation submodel of niobium-microalloyed steels is based on the nucleation and grain growth theory and additivity rule. The thermomechanical part of the modeling process was effectively carried out using the finite element method. Results were obtained in different temperatures, strain rates, and range of deformation. The thermomechanical treatments are different for two grades of niobium-steels to make possible analysis of the resulting structure and properties for different histories of deformation and chemical composition.

  19. 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...

  20. Mechanical properties of graphene nanoribbons

    Energy Technology Data Exchange (ETDEWEB)

    Faccio, Ricardo; Pardo, Helena; Goyenola, Cecilia; Mombru, Alvaro W [Crystallography, Solid State and Materials Laboratory (Cryssmat-Lab), DETEMA, Facultad de Quimica, Universidad de la Republica, Avenida General Flores 2124, PO Box 1157, Montevideo (Uruguay); Denis, Pablo A [Computational Nanotechnology, DETEMA, Facultad de Quimica, Universidad de la Republica, Avenida General Flores 2124, CC 1157, 11800 Montevideo (Uruguay)], E-mail: rfaccio@fq.edu.uy

    2009-07-15

    Herein, we investigate the structural, electronic and mechanical properties of zigzag graphene nanoribbons in the presence of stress by applying density functional theory within the GGA-PBE (generalized gradient approximation-Perdew-Burke-Ernzerhof) approximation. The uniaxial stress is applied along the periodic direction, allowing a unitary deformation in the range of {+-} 0.02%. The mechanical properties show a linear response within that range while a nonlinear dependence is found for higher strain. The most relevant results indicate that Young's modulus is considerable higher than those determined for graphene and carbon nanotubes. The geometrical reconstruction of the C-C bonds at the edges hardens the nanostructure. The features of the electronic structure are not sensitive to strain in this linear elastic regime, suggesting the potential for using carbon nanostructures in nano-electronic devices in the near future.

  1. Mechanical Property of Foamed Metal

    Institute of Scientific and Technical Information of China (English)

    LIU Pei-sheng; SANG Hai-bo

    2004-01-01

    A comprehensive study on the mechanical behavior of foamed metals was demonstrated. The relationship among their mechanical properties, preparation method, porosity and the structure was briefly studied as well.

  2. Mechanical Properties of Niobium Cavities

    Energy Technology Data Exchange (ETDEWEB)

    Ciovati, Gianluigi [Thomas Jefferson National Accelerator Facility, Newport News, VA (United States); Dhakal, Pashupati [Thomas Jefferson National Accelerator Facility, Newport News, VA (United States); Matalevich, Joseph R. [Thomas Jefferson National Accelerator Facility, Newport News, VA (United States); Myneni, Ganapati Rao [Thomas Jefferson National Accelerator Facility, Newport News, VA (United States)

    2015-09-01

    The mechanical stability of bulk Nb cavity is an important aspect to be considered in relation to cavity material, geometry and treatments. Mechanical properties of Nb are typically obtained from uniaxial tensile tests of small samples. In this contribution we report the results of measurements of the resonant frequency and local strain along the contour of single-cell cavities made of ingot and fine-grain Nb of different purity subjected to increasing uniform differential pressure, up to 6 atm. Measurements have been done on cavities subjected to different heat treatments. Good agreement between finite element analysis simulations and experimental data in the elastic regime was obtained with a single set of values of Young’s modulus and Poisson’s ratio. The experimental results indicate that the yield strength of medium-purity ingot Nb cavities is higher than that of fine-grain, high-purity Nb.

  3. 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.

  4. Mechanical Properties of Materials

    CERN Document Server

    Pelleg, Joshua

    2013-01-01

    The subject of mechanical behavior has been in the front line of basic studies in engineering curricula for many years.  This textbook was written for engineering students with the aim of presenting, in a relatively simple manner, the basic concepts of mechanical behavior in solid materials. A second aim of the book is to guide students in their laboratory experiments by helping them to understand their observations in parallel with the lectures of their various courses; therefore the first chapter of the book is devoted to mechanical testing. Another aim of the book is to provide practicing engineers with basic help to bridge the gap of time that has passed from their graduation up to their actual involvement in engineering work. The book also serves as the basis for more advanced studies and seminars when pursuing courses on a graduate level. The content of this textbook and the topics discussed correspond to courses that are usually taught in universities and colleges all over the world, but with a differ...

  5. Mechanical properties of metal dihydrides

    Science.gov (United States)

    Schultz, Peter A.; Snow, Clark S.

    2016-03-01

    First-principles calculations are used to characterize the bulk elastic properties of cubic and tetragonal phase metal dihydrides, \\text{M}{{\\text{H}}2} {\\text{M}   =  Sc, Y, Ti, Zr, Hf, lanthanides} to gain insight into the mechanical properties that govern the aging behavior of rare-earth di-tritides as the constituent 3H, tritium, decays into 3He. As tritium decays, helium is inserted in the lattice, the helium migrates and collects into bubbles, that then can ultimately create sufficient internal pressure to rupture the material. The elastic properties of the materials are needed to construct effective mesoscale models of the process of bubble growth and fracture. Dihydrides of the scandium column and most of the rare-earths crystalize into a cubic phase, while dihydrides from the next column, Ti, Zr, and Hf, distort instead into the tetragonal phase, indicating incipient instabilities in the phase and potentially significant changes in elastic properties. We report the computed elastic properties of these dihydrides, and also investigate the off-stoichiometric phases as He or vacancies accumulate. As helium builds up in the cubic phase, the shear moduli greatly soften, converting to the tetragonal phase. Conversely, the tetragonal phases convert very quickly to cubic with the removal of H from the lattice, while the cubic phases show little change with removal of H. The source and magnitude of the numerical and physical uncertainties in the modeling are analyzed and quantified to establish the level of confidence that can be placed in the computational results, and this quantified confidence is used to justify using the results to augment and even supplant experimental measurements.

  6. MECHANICAL PROPERTIES OF WROUGHT TUNGSTEN

    Science.gov (United States)

    Mechanical properties of wrought tungsten vol. II. Creep rupture test data from 1500 to 5000 F, and tensile test data from room temperature to 5000 F at various strain rates for tungsten sheet material.

  7. Mechanical properties of C-5 epimerized alginates.

    Science.gov (United States)

    Mørch, Y A; Holtan, S; Donati, I; Strand, B L; Skjåk-Braek, G

    2008-09-01

    There is an increased need for alginate materials with both enhanced and controllable mechanical properties in the fields of food, pharmaceutical and specialty applications. In the present work, well-characterized algal polymers and mannuronan were enzymatically modified using C-5 epimerases converting mannuronic acid residues to guluronic acid in the polymer chain. Composition and sequential structure of controls and epimerized alginates were analyzed by (1)H NMR spectroscopy. Mechanical properties of Ca-alginate gels were further examined giving Young's modulus, syneresis, rupture strength, and elasticity of the gels. Both mechanical strength and elasticity of hydrogels could be improved and manipulated by epimerization. In particular, alternating sequences were found to play an important role for the final mechanical properties of alginate gels, and interestingly, a pure polyalternating sample resulted in gels with extremely high syneresis and rupture strength. In conclusion, enzymatic modification was shown to be a valuable tool in modifying the mechanical properties of alginates in a highly specific manner.

  8. 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...

  9. Mechanical Properties of Composite Materials

    Directory of Open Access Journals (Sweden)

    Mitsuhiro Okayasu

    2014-10-01

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

  10. Mechanical property characterization of intraply hybrid composites

    Science.gov (United States)

    Chamis, C. C.; Lark, R. F.; Sinclair, J. H.

    1979-01-01

    An investigation of the mechanical properties of intraply hybrids made from graphite fiber/epoxy matrix hybridized with secondary S-glass or Kevlar 49 fiber composites is presented. The specimen stress-strain behavior was determined, showing that mechanical properties of intraply hybrid composites can be measured with available methods such as the ten-degree off-axis test for intralaminar shear, and conventional tests for tensile, flexure, and Izod impact properties. The results also showed that combinations of high modulus graphite/S-glass/epoxy matrix composites exist which yield intraply hybrid laminates with the best 'balanced' properties, and that the translation efficiency of mechanical properties from the constituent composites to intraply hybrids may be assessed with a simple equation.

  11. 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 f...... on a silicon substrate with a low-adhesion coating, whereas such motion on a noncoated substrate is limited to very short (sub-micrometer) nanofiber pieces due to strong adhesive forces....

  12. Mechanical properties of collagen fibrils

    OpenAIRE

    Wenger, M. P. E.; Bozec, L.; Horton, M. A.; Mesquida, P

    2007-01-01

    The formation of collagen fibers from staggered subfibrils still lacks a universally accepted model. Determining the mechanical properties of single collagen fibrils ( diameter 50 - 200 nm) provides new insights into collagen structure. In this work, the reduced modulus of collagen was measured by nanoindentation using atomic force microscopy. For individual type 1 collagen fibrils from rat tail, the modulus was found to be in the range from 5 GPa to 11.5 GPa ( in air and at room temperature)...

  13. Mechanical Properties of Ingot Nb Cavities

    Energy Technology Data Exchange (ETDEWEB)

    Ciovati, Gianluigi; Dhakal, Pashupati; Kneisel, Peter; Mammosser, John; Matalevich, Joseph; Rao Myneni, Ganapati

    2014-07-01

    This contribution presents the results of measurements of the resonant frequency and of strain along the contour of a single-cell cavity made of ingot Nb subjected to increasing uniform differential pressure, up to 6 atm. The data were used to infer mechanical properties of this material after cavity fabrication, by comparison with the results from simulation calculations done with ANSYS. The objective is to provide useful information about the mechanical properties of ingot Nb cavities which can be used in the design phase of SRF cavities intended to be built with this material.

  14. Mechanical properties of nanoparticles: basics and applications

    Science.gov (United States)

    Guo, Dan; Xie, Guoxin; Luo, Jianbin

    2014-01-01

    The special mechanical properties of nanoparticles allow for novel applications in many fields, e.g., surface engineering, tribology and nanomanufacturing/nanofabrication. In this review, the basic physics of the relevant interfacial forces to nanoparticles and the main measuring techniques are briefly introduced first. Then, the theories and important results of the mechanical properties between nanoparticles or the nanoparticles acting on a surface, e.g., hardness, elastic modulus, adhesion and friction, as well as movement laws are surveyed. Afterwards, several of the main applications of nanoparticles as a result of their special mechanical properties, including lubricant additives, nanoparticles in nanomanufacturing and nanoparticle reinforced composite coating, are introduced. A brief summary and the future outlook are also given in the final part.

  15. Physical and mechanical properties of hemp seed

    Science.gov (United States)

    Taheri-Garavand, A.; Nassiri, A.; Gharibzahedi, S. M. T.

    2012-04-01

    The current study was conducted to investigate the effect of moisture content on the post-harvest physical and mechanical properties of hemp seed in the range of 5.39 to 27.12% d.b. Results showed that the effect of moisture content on the most physical properties of the grain was significant (Phemp seed was not significant. However, the moisture content effect on rupture force and energy was significant (Phemp seed were significant (P<0.05).

  16. Mechanical properties of wet granular materials

    Energy Technology Data Exchange (ETDEWEB)

    Fournier, Z; Geromichalos, D; Herminghaus, S; Kohonen, M M; Mugele, F; Scheel, M; Schulz, M; Schulz, B; Schier, Ch; Seemann, R; Skudelny, A

    2005-03-09

    We elaborate on the impact of liquids upon the mechanical properties of granular materials. We find that most of the experimental and simulation results may be accounted for by a simple model assuming frictionless, spherical grains, with a hysteretic attractive interaction between neighbouring grains due to capillary forces.

  17. Mechanical Properties of Nanocrystal Supercrystals

    Energy Technology Data Exchange (ETDEWEB)

    Tam, Enrico; Podsiadlo, Paul; Shevchenko, Elena; Ogletree, D. Frank; Delplancke-Ogletree, Marie-Paule; Ashby, Paul D.

    2009-12-30

    Colloidal nanocrystals attract significant interest due to their potential applications in electronic, magnetic, and optical devices. Nanocrystal supercrystals (NCSCs) are particularly appealing for their well ordered structure and homogeneity. The interactions between organic ligands that passivate the inorganic nanocrystal cores critically influence their self-organization into supercrystals, By investigating the mechanical properties of supercrystals, we can directly characterize the particle-particle interactions in a well-defined geometry, and gain insight into both the self-assembly process and the potential applications of nanocrystal supercrystals. Here we report nanoindentation studies of well ordered lead-sulfide (Pbs) nanocrystal supercrystals. Their modulus and hardness were found to be similar to soft polymers at 1.7 GPa and 70 MPa respectively and the fractures toughness was 39 KPa/m1/2, revealing the extremely brittle nature of these materials.

  18. Microstructure and mechanical properties of MTG YBCO

    Science.gov (United States)

    Li, L. F.; Zhang, Z.; Jin, D.; Li, Y. Y.; Meriani, S.

    1997-08-01

    MTG (melt-texture-growth) samples were prepared by passing teh YBa2Cu3O7-x pellets (solid state reaction products) through a furnace with a temperature gradient of 15 °C for 5, 10 and 15 min, respectively. The Jc value, Vickers hardness and fracture toughness of the above samples were measured. And the results indicated that 211 precipitates can influence not only the critical current density, but also the mechanical properties According to microstructure analysis and fracture mechanics theory, the effects of 211 precipatates which can act as a toughening agent on mechanical gains were discussed in this paper.

  19. Mechanical properties of polyethylene foils

    Directory of Open Access Journals (Sweden)

    Ľubomír KUBÍK

    2014-03-01

    Full Text Available The paper deals with the evaluation of the mechanical properties of the polyethylene foils such as the stress, strain, modulus of elasticity and stress and strain in the moment of breaking. The thin foils (50 mm which contained 91 % of polyethylene Bralen RA 2–63 and 9 % colored concentrate Maxithen were studied. Four sorts of foils were examined: Maxithen HP 1510 – white, Maxithen HP 231111 – yellow, Maxithen HP 533031 – blue and Maxithen HP 533 041 – violet. Longitudinal and transversal tensile properties were studied. The tensile behavior was monitored on the motorized test stand ANDILOG STENTOR 1000. The moduli of elasticity of longitudinal samples of polyethylene Bralen RA 2—63 foils achieved the values in the range from 222.73 MPa to 298.24 MPa and the transversal samples in the range 179.61 MPa to 270.41 MPa. The stress of longitudinal samples of polyethylene Bralen RA 2–63 foils in the moment of the rupture achieved the values in the range from 9.46 MPa to 13.33 MPa at the strain from 1.51 mm*mm–1 to 1.54 mm*mm–1 and the transversal samples in the range from 12.38 MPa to 15.54 MPa at the strain from 1.48 mm*mm–1 to 1.58 mm*mm–1.

  20. 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.

  1. Mechanical properties of additively manufactured octagonal honeycombs.

    Science.gov (United States)

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

    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.

  2. Mechanical Properties of Polymer Nano-composites

    Science.gov (United States)

    Srivastava, Iti

    Thermoset polymer composites are increasingly important in high-performance engineering industries due to their light-weight and high specific strength, finding cutting-edge applications such as aircraft fuselage material and automobile parts. Epoxy is the most widely employed thermoset polymer, but is brittle due to extensive cross-linking and notch sensitivity, necessitating mechanical property studies especially fracture toughness and fatigue resistance, to ameliorate the low crack resistance. Towards this end, various nano and micro fillers have been used with epoxy to form composite materials. Particularly for nano-fillers, the 1-100 nm scale dimensions lead to fascinating mechanical properties, oftentimes proving superior to the epoxy matrix. The chemical nature, topology, mechanical properties and geometry of the nano-fillers have a profound influence on nano-composite behavior and hence are studied in the context of enhancing properties and understanding reinforcement mechanisms in polymer matrix nano-composites. Using carbon nanotubes (CNTs) as polymer filler, uniquely results in both increased stiffness as well as toughness, leading to extensive research on their applications. Though CNTs-polymer nano-composites offer better mechanical properties, at high stress amplitude their fatigue resistance is lost. In this work covalent functionalization of CNTs has been found to have a profound impact on mechanical properties of the CNT-epoxy nano-composite. Amine treated CNTs were found to give rise to effective fatigue resistance throughout the whole range of stress intensity factor, in addition to significantly enhancing fracture toughness, ductility, Young's modulus and average hardness of the nano-composite by factors of 57%, 60%, 30% and 45% respectively over the matrix as a result of diminished localized cross-linking. Graphene, a one-atom-thick sheet of atoms is a carbon allotrope, which has garnered significant attention of the scientific community and is

  3. Mechanical Properties of Palm Fiber Mattress

    Science.gov (United States)

    Li, Yu-Qian; Wu, Jia-Yu; Gu, Hao-Wei; Chen, Zong-Yong; Shi, Xiao-Bing; Liao, Ting-Mao; An, Cheng; Yuan, Hong; Liu, Ren-Huai

    2016-05-01

    Palm fiber mattress is increasingly accepted by many families. This study aims at evaluating the mechanical properties of palm fiber mattress. Two experiments were conduct to investigate the Young's modulus of palm fiber mattress in three directions. In addition, finite element models were established to characterize palm fiber mattress under uniform distributed pressure. Finally, results from finite element analysis are presented to illustrate that the thick mattress will stick with human body curve perfectly, which can support vertebral column effectively.

  4. Conference on Mathematical Results in Quantum Mechanics

    CERN Document Server

    Exner, Pavel; Tater, Miloš; QMath-7

    1999-01-01

    At the age of almost three quarters of a century, quantum mechanics is by all accounts a mature theory. There were times when it seemed that it had borne its best fruit already and would give way to investigation of deeper levels of matter. Today this sounds like rash thinking. Modern experimental techniques have led to discoveries of numerous new quantum effects in solid state, optics and elsewhere. Quantum mechanics is thus gradually becoming a basis for many branches of applied physics, in this way entering our everyday life. While the dynamic laws of quantum mechanics are well known, a proper theoretical understanding requires methods which would allow us to de­ rive the abundance of observed quantum effects from the first principles. In many cases the rich structure hidden in the Schr6dinger equation can be revealed only using sophisticated tools. This constitutes a motivation to investigate rigorous methods which yield mathematically well-founded properties of quantum systems.

  5. 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.

  6. Research on mechanical properties of corn stalk

    Science.gov (United States)

    Zhang, Kaifei; He, Yujing; Zhang, Hongmei; Li, He

    2017-03-01

    Many domestic scholars have studied on straw utilization from lodging resistance, by breeding agricultural experts to optimization parameters, which selected by agricultural mechanical experts and efficient utilization after the harvest crush. Therefore, the study of the mechanical properties of corn stalks has great prospects. It can provide the basis for the design of agricultural machinery and comprehensive utilization of straw that study the relationship between the properties of the corn stalk and the mechanical properties. In this paper, the radial compression and bending mechanical properties of corn stalk was conducted by universal material testing machine, which contributes to the increase of corn crop and provides basis for the development of equipment.

  7. Mechanical Properties of Autoclaved Shell-aggregate

    Institute of Scientific and Technical Information of China (English)

    MA Hailong; CUI Chong; LI Xing; Pierre Chevrier; Vanessa Bouchart; TANG Feng

    2011-01-01

    Waste solid propylene oxide sludge(POS)and fly ash were used as main raw material to prepare propylene oxide sludge aggregate(POSA)under the condition of autoclaved(180 ℃,1.0 MPa)curing.Three different test methods namely cylinder compressive strength(CCS),individual aggregate compressive strength(IACS)and strength contribution rate(SCR)proposed were used to characterize the mechanical properties of the autoclaved POSA.POS shell-aggregate with SCR of 94% were prepared under the hydrothermal synthesis and autoclaved curing.The experimental results indicate that CCS and IACS have good consistency in characterizing mechanical properties of POSA.It is suggested that SCR not only can characterize the strength of POSA core,but also can reflect the effect of shell on the performance of POSA.By means of least square method,relationships between CCS and IACS,CCS and SCR,IACS and SCR were deduced.

  8. 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.

  9. 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.

  10. Different mechanical properties in Seldinger guide wires

    Directory of Open Access Journals (Sweden)

    Wolfram Schummer

    2015-01-01

    Full Text Available Background and Aims: Most central venous catheters are placed using Seldinger guide wires. EN ISO 11070 is the guideline for testing guide wire flexing performance and tensile strength, and we can safely assume that guide wires in use meet these requirements. Unfortunately, EN ISO 11070 guidelines do not reflect the clinical requirements and we continue to see mechanical failures and their associated complications. Material and Methods: This in vitro study was performed in an accredited laboratory. With regard to flexing, we: (1 Established the minimum flexing performance needed to meet clinical requirements, (2 developed flexing performance tests which mimic clinical requirement, and (3 evaluated the mechanical properties of various guide wires relative to these requirements. With regard to tensile strength, we used the testing method prescribed in ISO 11070, but did not end the test at 5 Newton (N. We continued until the guide wire was damaged, or we reached maximum tractive force. We then did a wire-to-wire comparison. We examined two basic wire constructions, monofil and core and coil. Results: Tensile strength: All wires tested, except one, met EN ISO 11070 requirements for 5 N tensile strength. The mean of the wire types tested ranged from 15.06 N to 257.76 N. Flexing performance: None of the wires kinked. The monofil had no evidence of bending. Two core/coil wires displayed minor bending (angle 1.5°. All other wires displayed bending angles between 22.5° and 43.0°. Conclusion: We recommend that: (1 Clinicians use guide wires with high-end mechanical properties, (2 EN ISO 11070 incorporate our flexing test into their testing method, raise the flexing requirement to kink-proof, (3 and raise the tensile strength requirement to a minimum of 30 N, and (3 all manufacturers and suppliers be required to display mechanical properties of all guide wire, and guide wire kits sold.

  11. Investigation on Mechanical Property of Seamless Pipe

    Institute of Scientific and Technical Information of China (English)

    ZHAO Li-ming; YANG Xiao-yong; LIU Ye

    2004-01-01

    The mechanical properties of the steel pipe rolled with continuously casting round billet after determining the chemical composition in steel were studied. The results show that the total reduction ratio should be higher than 5.2 when the line pipes of grade B, grade 20 and other general seamless pipe were rolled with continuously casting round billet. And the total reduction ratio should be higher than 10.2 and the grain size should be controlled more than grade 7 for casing of oil countryside tubular goods (OCTG).

  12. Mechanical properties of non-woven glass fiber geopolymer composites

    Science.gov (United States)

    Rieger, D.; Kadlec, J.; Pola, M.; Kovářík, T.; Franče, P.

    2017-02-01

    This experimental research focuses on mechanical properties of non-woven glass fabric composites bound by geopolymeric matrix. This study investigates the effect of different matrix composition and amount of granular filler on the mechanical properties of final composites. Matrix was selected as a metakaolin based geopolymer hardened by different amount of potassium silicate activator. The ceramic granular filler was added into the matrix for investigation of its impact on mechanical properties and workability. Prepared pastes were incorporated into the non-woven fabrics by hand roller and final composites were stacked layer by layer to final thickness. The early age hardening of prepared pastes were monitored by small amplitude dynamic rheology approach and after 28 days of hardening the mechanical properties were examined. The electron microscopy was used for detail description of microstructural properties. The imaging methods revealed good wettability of glass fibers by geopolymeric matrix and results of mechanical properties indicate usability of these materials for constructional applications.

  13. Thermal-Mechanical Stress Analysis of PWR Pressure Vessel and Nozzles under Grid Load-Following Mode: Interim Report on the Effect of Cyclic Hardening Material Properties and Pre-existing Cracks on Stress Analysis Results

    Energy Technology Data Exchange (ETDEWEB)

    Mohanty, Subhasish [Argonne National Lab. (ANL), Argonne, IL (United States); Soppet, William [Argonne National Lab. (ANL), Argonne, IL (United States); Majumdar, Saurin [Argonne National Lab. (ANL), Argonne, IL (United States); Natesan, Ken [Argonne National Lab. (ANL), Argonne, IL (United States)

    2016-03-15

    This report provides an update on an assessment of environmentally assisted fatigue for light water reactor components under extended service conditions. This report is a deliverable under the work package for environmentally assisted fatigue as part of DOE’s Light Water Reactor Sustainability Program. In a previous report (September 2015), we presented tensile and fatigue test data and related hardening material properties for 508 low-alloys steel base metal and other reactor metals. In this report, we present thermal-mechanical stress analysis of the reactor pressure vessel and its hot-leg and cold-leg nozzles based on estimated material properties. We also present results from thermal and thermal-mechanical stress analysis under reactor heat-up, cool-down, and grid load-following conditions. Analysis results are given with and without the presence of preexisting cracks in the reactor nozzles (axial or circumferential crack). In addition, results from validation stress analysis based on tensile and fatigue experiments are reported.

  14. Mechanical deformation mechanisms and properties of amyloid fibrils.

    Science.gov (United States)

    Choi, Bumjoon; Yoon, Gwonchan; Lee, Sang Woo; Eom, Kilho

    2015-01-14

    Amyloid fibrils have recently received attention due to their remarkable mechanical properties, which are highly correlated with their biological functions. We have studied the mechanical deformation mechanisms and properties of amyloid fibrils as a function of their length scales by using atomistic simulations. It is shown that the length of amyloid fibrils plays a role in their deformation and fracture mechanisms in such a way that the competition between shear and bending deformations is highly dependent on the fibril length, and that as the fibril length increases, so does the bending strength of the fibril while its shear strength decreases. The dependence of rupture force for amyloid fibrils on their length is elucidated using the Bell model, which suggests that the rupture force of the fibril is determined from the hydrogen bond rupture mechanism that critically depends on the fibril length. We have measured the toughness of amyloid fibrils, which is shown to depend on the fibril length. In particular, the toughness of the fibril with its length of ∼3 nm is estimated to be ∼30 kcal mol(-1) nm(-3), comparable to that of a spider silk crystal with its length of ∼2 nm. Moreover, we have shown the important effect of the pulling rate on the mechanical deformation mechanisms and properties of amyloid fibril. It is found that as the pulling rate increases, so does the contribution of the shear effect to the elastic deformation of the amyloid fibril with its length of deformation mechanism of the amyloid fibril with its length of >15 nm is almost independent of the pulling rate. Our study sheds light on the role of the length scale of amyloid fibrils and the pulling rate in their mechanical behaviors and properties, which may provide insights into how the excellent mechanical properties of protein fibrils can be determined.

  15. 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.

  16. Some Mechanical Properties of Austempered Ductile Iron

    Science.gov (United States)

    Waanders, F. B.; Vorster, S. W.; Vorster, M. J.

    1998-12-01

    In the present investigation the influence of the microstructure, obtained after an austempering treatment in a "process window", on the mechanical properties of austempered ductile iron has been investigated. These properties include tensile strength, elongation and hardness. Conversion electron Mössbauer spectra (CEMS) were measured, after heat treatment.

  17. Some mechanical properties of austempered ductile iron

    Energy Technology Data Exchange (ETDEWEB)

    Waanders, F.B.; Vorster, S.W.; Vorster, M.V. [Potchefstroom Univ. (South Africa). Dept. of Metall. Eng.

    1997-12-01

    In the present investigation the influence of the microstructure, obtained after an austempering treatment in a ``process window``, on the mechanical properties of austempered ductile iron has been investigated. These properties include tensile strength, elongation and hardness. Conversion electron Moessbauer spectra (CEMS) were measured, after heat treatment. (orig.). 7 refs.

  18. Some Mechanical Properties of Austempered Ductile Iron

    Energy Technology Data Exchange (ETDEWEB)

    Waanders, F.B.; Vorster, S.W.; Vorster, M.J. [Potchefstroom University, Department of Metallurgical Engineering (South Africa)

    1998-12-15

    In the present investigation the influence of the microstructure, obtained after an austempering treatment in a 'process window', on the mechanical properties of austempered ductile iron has been investigated. These properties include tensile strength, elongation and hardness. Conversion electron Moessbauer spectra (CEMS) were measured, after heat treatment.

  19. Mechanical properties of UV irradiated rat tail tendon (RTT) collagen.

    Science.gov (United States)

    Sionkowska, Alina; Wess, Tim

    2004-04-01

    The mechanical properties of RTT collagen tendon before and after UV irradiation have been investigated by mechanical testing (Instron). Air-dried tendon were submitted to treatment with UV irradiation (wavelength 254 nm) for different time intervals. The changes in such mechanical properties as breaking strength and percentage elongation have been investigated. The results have shown, that the mechanical properties of the tendon were greatly affected by time of UV irradiation. Ultimate tensile strength and ultimate percentage elongation decreased after UV irradiation of the tendon. Increasing UV irradiation leads to a decrease in Young's modulus of the tendon.

  20. 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

  1. Mechanical properties of 3D ceramic nanolattices

    Science.gov (United States)

    Meza, Lucas

    Developments in advanced nanoscale fabrication techniques have allowed for the creation of 3-dimensional hierarchical structural meta-materials that can be designed with arbitrary geometry. These structures can be made on length scales spanning multiple orders of magnitude, from tens of nanometers to hundreds of microns. The smallest features are controllable on length scales where materials have been shown to exhibit size effects in their mechanical properties. Combining novel nanoscale mechanical properties with a 3-dimensional architecture enables the creation of new classes of materials with tunable and unprecedented mechanical properties. We present the fabrication and mechanical deformation of hollow tube alumina nanolattices that were fabricated using two-photon lithography direct laser writing (DLW), atomic layer deposition (ALD), and oxygen plasma etching. Nanolattices were designed in a number of different geometries including octet-truss, octahedron, and 3D Kagome. Additionally, a number of structural parameters were varied including tube wall thickness (t) , tube major axis (a) , and unit cell size (L) . The resulting nanolattices had a range of densities from ρ = 4 to 250 mg/cm3. Uniaxial compression and cyclic loading tests were performed on the nanolattices to obtain the yield strength and modulus. In these tests, a marked change in the deformation response was observed when the wall thickness was reduced below 20nm; thick-walled nanolattices (t>20nm) underwent catastrophic, brittle failure, which transitioned to a gradual, ductile-like deformation as wall thickness was reduced. Thick-walled nanolattices also exhibited no recovery after compression, while thin-walled structures demonstrated notable recovery, with some recovering by 98% after compression to 50% strain and by 80% when compressed to 90% strain. Across all geometries, unit cell sizes, and wall thicknesses, we found a consistent power law relation between strength and modulus with

  2. Mechanical Properties of Crystalline Silicon Carbide Nanowires.

    Science.gov (United States)

    Zhang, Huan; Ding, Weiqiang; Aidun, Daryush K

    2015-02-01

    In this paper, the mechanical properties of crystalline silicon carbide nanowires, synthesized with a catalyst-free chemical vapor deposition method, were characterized with nanoscale tensile testing and mechanical resonance testing methods inside a scanning electron microscope. Tensile testing of individual silicon carbide nanowire was performed to determine the tensile properties of the material including the tensile strength, failure strain and Young's modulus. The silicon carbide nanowires were also excited to mechanical resonance in the scanning electron microscope vacuum chamber using mechanical excitation and electrical excitation methods, and the corresponding resonance frequencies were used to determine the Young's modulus of the material according to the simple beam theory. The Young's modulus values from tensile tests were in good agreement with the ones obtained from the mechanical resonance tests.

  3. Mechanical properties of stabilized artificial organic soil

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    In order to study the influence of organic matter on the mechanical properties of stabilized soil and the effect of XGL2005 on stabilizing organic soil,unconfined compressive strength tests were carried out.Test results indicated that the strength of stabilized soil decreased in the form of a logarithmic function as the organic matter content increased.In contrast,the strength increased in the form of a power function as the content of the stabilization agent increased.The strength of cement stabilized organic soil was reinforced greatly by adding the stabilizer XGL2005.Based on the law obtained from the test,a strength prediction model was established by regression analysis.The model included the influence of the curing time,the content of the cement,the organic matter content and the stabilization agent on the strength of stabilized soil.

  4. 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.

  5. 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 bond...... 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.......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...

  6. Mechanical Properties of Layered Hybrid Fiber Reinforced Concrete

    Institute of Scientific and Technical Information of China (English)

    YUAN Hai-qing; CHEN Jing-tao; ZHU Ji-dong

    2003-01-01

    To improve the mechanical properties of concrete,Layered Hybrid Fiber Reinforced Concrete (LHFRC) was developed in this paper.Through comparative tests,the effects of layered hybrid fibers on a series of mechanical properties of concrete were discussed.The mechanical properties include compressive strength,tensile strength,flexural strength,compressive stress-strain relationship,flexural toughness and cracking resistance of concrete.The testing results and analysis demonstrate that layered hybrid fibers can significantly improve the flexural strength,toughness and cracking resistance of concrete while the cost of concrete increases slightly.

  7. Stainless Steel Microstructure and Mechanical Properties Evaluation

    Energy Technology Data Exchange (ETDEWEB)

    Switzner, Nathan T

    2010-06-01

    A nitrogen strengthened 21-6-9 stainless steel plate was spinformed into hemispherical test shapes. A battery of laboratory tests was used to characterize the hemispheres. The laboratory tests show that near the pole (axis) of a spinformed hemisphere the yield strength is the lowest because this area endures the least “cold-work” strengthening, i.e., the least deformation. The characterization indicated that stress-relief annealing spinformed stainless steel hemispheres does not degrade mechanical properties. Stress-relief annealing reduces residual stresses while maintaining relatively high mechanical properties. Full annealing completely eliminates residual stresses, but reduces yield strength by about 30%.

  8. VERIFICATION OF TORSIONAL OSCILLATING MECHANICAL SYSTEM DYNAMIC CALCULATION RESULTS

    Directory of Open Access Journals (Sweden)

    Peter KAŠŠAY

    2014-09-01

    Full Text Available On our department we deal with optimization and tuning of torsional oscillating mechanical systems. When solving these problems we often use results of dynamic calculation. The goal of this article is to compare values obtained by computation and experimentally. For this purpose, a mechanical system built in our laboratory was used. At first, classical HARDY type flexible coupling has been applied into the system, then we used a pneumatic flexible shaft coupling developed by us. The main difference of these couplings over conventional flexible couplings is that they can change their dynamic properties during operation, by changing the pressure of the gaseous medium in their flexible elements.

  9. 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.

  10. Mechanical properties of thermoelectric lanthanum telluride from quantum mechanics

    Science.gov (United States)

    Li, Guodong; Aydemir, Umut; Wood, Max; Goddard, William A., III; Zhai, Pengcheng; Zhang, Qingjie; Snyder, G. Jeffrey

    2017-07-01

    Lanthanum telluride (La3Te4) is an n-type high-performance thermoelectric material in the high temperature range, but its mechanical properties remain unknown. Since we want robust mechanical properties for their integration into industrial applications, we report here quantum mechanics (QM) simulations to determine the ideal strength and deformation mechanisms of La3Te4 under pure shear deformations. Among all plausible shear deformation paths, we find that shearing along the (0 0 1)/ slip system has the lowest ideal shear strength of 0.99 GPa, making it the most likely slip system to be activated under pressure. We find that the long range La-Te ionic interactions play the predominant role in resisting shear deformation. To enhance the mechanical strength, we suggest improving the long ionic La-Te bond stiffness to strengthen the ionic La-Te framework in La3Te4 by a defect-engineering strategy, such as partial substitution of La by Ce or Pr having isotypic crystal structures. This work provides the fundamental information to understand the intrinsic mechanics of La3Te4.

  11. Structural Properties and Mechanical Durability of Extruded Fish Feed

    DEFF Research Database (Denmark)

    Haubjerg, Anders Fjeldbo; Veje, Christian; Jørgensen, Bo Nørregaard;

    2015-01-01

    This article investigates the possible correlation between mechanical properties of fish feed pellets and their mechanical durability. Mechanical properties were obtained by texture profile analysis (TPA) and stress relaxation test (SRT) of different types of fish feed. The results were correlated...... against a conventional test of mechanical durability (DORIS, Durability On a Realistic, test). From SRT it was found that for achieving a high durability, pellets should be able to relax an applied force nonelastically. From TPA, it was found that a durable pellet should also be able to return its...

  12. 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

  13. Microstructure and mechanical properties of neoprene montmorillonite nanocomposites

    Science.gov (United States)

    Yeh, Meng-Heng; Hwang, Weng-Sing; Cheng, Lin-Ri

    2007-03-01

    To investigate the microstructure and mechanical properties of neoprene-montmorillonite nanocomposite, three modified montmorillonite are used. An X-ray diffractometer is used to measure the corresponding change in d-spacing. Scanning electron microscopy is employed to investigate the morphology of the various composites. Transmission electron microscopy is employed to investigate the composite of montmorillonite and neoprene. The results indicate that the addition of montmorillonite enhances the mechanical properties of neoprene significantly.

  14. 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.)

  15. A Study in Physical and Mechanical Properties of Hemp Fibres

    Directory of Open Access Journals (Sweden)

    Asim Shahzad

    2013-01-01

    Full Text Available This paper presents the results of the experiments undertaken to evaluate various physical and mechanical properties of hemp fibres. The study of these properties is vital for comparison with similar properties of synthetic fibres and for assessing hemp fibres’ suitability for use as reinforcement in composite materials. The properties of hemp fibres were found to be good enough to be used as reinforcement in composite materials. However, the issues of relatively high moisture content of fibres, variability in fibre properties, and relatively poor fibre/matrix interfacial strength were identified as factors that can reduce the efficiency with which these fibres can be utilised.

  16. 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.

  17. Mechanical and Morphological Properties of Nano Filler Polyester Composites

    Directory of Open Access Journals (Sweden)

    Bonnia Noor Najmi

    2016-01-01

    Full Text Available This research is focusing on mechanical and morphological properties of unsaturated polyester (UP reinforced with two different types of filler which is nano size clay Cloisite 30B (C30B and Carbon Black (CB. Samples were fabricated via hand lay-up and open molding technique. Percentages of Cloisite 30B & Carbon Black (CB used vary from 0, 2, 4, 6, 8 and 10 wt%. The mechanical properties were evaluated by impact, flexural and hardness testing. Result shows that the mechanical strength of C30B was better compare to CB filled composite. The combination of UP with C30B helps to improve the properties due to the high surface area of nanosize filler in the matrix. The result shows that increasing of filler content had increased mechanical properties of composites. Optimum percentage represent good mechanical properties are 4% for both fillers. SEM images showed that rough surface image indicate to agglomeration of filler in the matrix for CB sample and smooth surface image on C30B sample indicate to homogenous blending between filler and matrix polyester. SEM images proved that mechanical properties result indicate that C30B polyester composite is a good reinforcement compare to CB polyester composite.

  18. Improvement of mechanical properties of glass substrates

    Science.gov (United States)

    Karbay, Ismail Hakki Cengizhan; Budakoglu, Refika; Zayim, Esra Ozkan

    2015-12-01

    This paper aims to enhance the mechanical and optical properties of glass substrates with thin films by the sol-gel method. TiO2-SiO2 binary system and Ta2O5 were deposited on glass substrates with high transparency. Ring-on-ring flexure and scratch tests were the main mechanical characterization tests. Herein, we report that the thin films can be used to enhance the mechanical properties of the glass substrates efficiently and effectively. TiO2-SiO2 binary system shows more than two times and Ta2O5 thin films show nearly three times better ultimate strength in the ring-on-ring flexure test. Besides, Ta2O5 thin film samples show superior scratch resistance. Additionally, the finite element method was also used to check the conformity in the application of mechanical properties of composite materials. It is also worth noting that, the finite element method can be used to accurately analyze the mechanical stability of composite materials. The use of the finite element method can reduce the total number of experimental trials without losing reliability.

  19. 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.

  20. Determination of Mechanical Properties of Micromembranes with Compressive Residual Stress

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    A novel model of a load-deflection method to determine the mechanical properties of micromembranes with compressive residual stress is described. Since thin film structures are frequently used in micro devices, characterisation of mechanical properties of thin films is desired by the design and fabrication of micromachines. In this paper, the mechanical properties of thin micromembranes under compressive stress are characterised, which are fabricated by bulk micromachining. The relation between the center deflection and the load pressure on a square membrane is deduced by modelling the membrane as an elastic plate having large deflection with clamped boundaries. According to the model, whether the membrane has initial deflection or not has no effect on the measurement result. The Young's modulus and residual stress are simultaneously determined. The mechanical properties of siliconoxide, silicon nitride membranes and composite membranes of polysilicon with silicon nitride are measured.

  1. Investigation of Mechanical Properties of Cryogenically Treated Music Wire

    CERN Document Server

    Heptonstall, A; Robertson, N A

    2015-01-01

    It has been reported that treating music wire (high carbon steel wire) by cooling to cryogenic temperatures can enhance its mechanical properties with particular reference to those properties important for musical performance. We use such wire for suspending many of the optics in Advanced LIGO, the upgrade to LIGO - the Laser Interferometric Gravitational-Wave Observatory. Two properties that particularly interest us are mechanical loss and breaking strength. A decrease in mechanical loss would directly reduce the thermal noise associated with the suspension, thus enhancing the noise performance of mirror suspensions within the detector. An increase in strength could allow thinner wire to be safely used, which would enhance the dilution factor of the suspension, again leading to lower suspension thermal noise. In this article we describe the results of an investigation into some of the mechanical properties of music wire, comparing untreated wire with the same wire which has been cryogenically treated. For th...

  2. Mechanical Properties of Cellulose Microfiber Reinforced Polyolefin

    Science.gov (United States)

    Kobayashi, Satoshi; Yamada, Hiroyuki

    Cellulose microfiber (CeF) has been expected as a reinforcement of polymer because of its high modulus and strength and lower cost. In the present study, mechanical properties of CeF/polyolefin were investigated. Tensile modulus increased with increasing CeF content. On the other hand, tensile strength decreased. Fatigue properties were also investigated with acoustic emission measurement. Stiffness of the composites gradually decreased with loading. Drastic decrease in stiffness was observed just before the final fracture. Based on the Mori-Tanaka's theory, the method to calculate modulus of CeF were proposed to evaluate dispersion of CeF.

  3. Primate dietary ecology in the context of food mechanical properties.

    Science.gov (United States)

    Coiner-Collier, Susan; Scott, Robert S; Chalk-Wilayto, Janine; Cheyne, Susan M; Constantino, Paul; Dominy, Nathaniel J; Elgart, Alison A; Glowacka, Halszka; Loyola, Laura C; Ossi-Lupo, Kerry; Raguet-Schofield, Melissa; Talebi, Mauricio G; Sala, Enrico A; Sieradzy, Pawel; Taylor, Andrea B; Vinyard, Christopher J; Wright, Barth W; Yamashita, Nayuta; Lucas, Peter W; Vogel, Erin R

    2016-09-01

    Substantial variation exists in the mechanical properties of foods consumed by primate species. This variation is known to influence food selection and ingestion among non-human primates, yet no large-scale comparative study has examined the relationships between food mechanical properties and feeding strategies. Here, we present comparative data on the Young's modulus and fracture toughness of natural foods in the diets of 31 primate species. We use these data to examine the relationships between food mechanical properties and dietary quality, body mass, and feeding time. We also examine the relationship between food mechanical properties and categorical concepts of diet that are often used to infer food mechanical properties. We found that traditional dietary categories, such as folivory and frugivory, did not faithfully track food mechanical properties. Additionally, our estimate of dietary quality was not significantly correlated with either toughness or Young's modulus. We found a complex relationship among food mechanical properties, body mass, and feeding time, with a potential interaction between median toughness and body mass. The relationship between mean toughness and feeding time is straightforward: feeding time increases as toughness increases. However, when considering median toughness, the relationship with feeding time may depend upon body mass, such that smaller primates increase their feeding time in response to an increase in median dietary toughness, whereas larger primates may feed for shorter periods of time as toughness increases. Our results emphasize the need for additional studies quantifying the mechanical and chemical properties of primate diets so that they may be meaningfully compared to research on feeding behavior and jaw morphology.

  4. 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

  5. Mechanical properties of silicones for MEMS

    Science.gov (United States)

    Schneider, F.; Fellner, T.; Wilde, J.; Wallrabe, U.

    2008-06-01

    This paper focuses on the mechanical properties of polydimethylsiloxane (PDMS) relevant for microelectromechanical system (MEMS) applications. In view of the limited amount of published data, we analyzed the two products most commonly used in MEMS, namely RTV 615 from Bayer Silicones and Sylgard 184 from Dow Corning. With regard to mechanical properties, we focused on the dependence of the elastic modulus on the thinner concentration, temperature and strain rate. In addition, creep and thermal aging were analyzed. We conclude that the isotropic and constant elastic modulus has strong dependence on the hardening conditions. At high hardening temperatures and long hardening time, RTV 615 displays an elastic modulus of 1.91 MPa and Sylgard 184 of 2.60 MPa in a range up to 40% strain.

  6. Mechanical properties of functionalized carbon nanotubes

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Z Q; Liu, B; Chen, Y L; Hwang, K C [FML, Department of Engineering Mechanics, Tsinghua University, Beijing 100084 (China); Jiang, H [Department of Mechanical and Aerospace Engineering, Arizona State University, Tempe, AZ 85287 (United States); Huang, Y [Department of Civil and Environmental Engineering, Northwestern University, Evanston, IL 60208 (United States)], E-mail: liubin@tsinghua.edu.cn, E-mail: y-huang@northwestern.edu

    2008-10-01

    Carbon nanotubes (CNTs) used to reinforce polymer matrix composites are functionalized to form covalent bonds with the polymer in order to enhance the CNT/polymer interfaces. These bonds destroy the perfect atomic structures of a CNT and degrade its mechanical properties. We use atomistic simulations to study the effect of hydrogenization on the mechanical properties of single-wall carbon nanotubes. The elastic modulus of CNTs gradually decreases with the increasing functionalization (percentage of C-H bonds). However, both the strength and ductility drop sharply at a small percentage of functionalization, reflecting their sensitivity to C-H bonds. The cluster C-H bonds forming two rings leads to a significant reduction in the strength and ductility. The effect of carbonization has essentially the same effect as hydrogenization.

  7. New approach of eggshell mechanical properties determinantion

    Directory of Open Access Journals (Sweden)

    Libor Severa

    2010-01-01

    Full Text Available The paper describes a new approach for determination of mechanical properties of hen’s eggshell. The suitability and applicability of a Berkovich indentation is discussed. The eggshells were tested in the area surrounding equator line. The deformation modes active during indentation have been examinined from the shape of load-displacement curves. According to measured dependencies, the eggshel shown an viscous-elastic deformation.The values of Young’s modulus E obtained from radial and tangential directions did not vary significantly. This fact shows on isotropic nature of eggshell structure. It was found that values of E do not significantly change neither around the cir­cum­fe­ren­ce of the equator. The values obtained within this research correspond to values reported in literature and obtained on macroscopic samples. Nanoindentation was found to be a precise and powerful tool, suitable for determining local variations of mechanical properties of eggshells.

  8. Mechanical and Morphological Properties of Nano Filler Polyester Composites

    OpenAIRE

    Bonnia Noor Najmi; Redzuan Aein Afina; Shuhaimeen Nurul Shakirah

    2016-01-01

    This research is focusing on mechanical and morphological properties of unsaturated polyester (UP) reinforced with two different types of filler which is nano size clay Cloisite 30B (C30B) and Carbon Black (CB). Samples were fabricated via hand lay-up and open molding technique. Percentages of Cloisite 30B & Carbon Black (CB) used vary from 0, 2, 4, 6, 8 and 10 wt%. The mechanical properties were evaluated by impact, flexural and hardness testing. Result shows that the mechanical strength of ...

  9. Mechanical Properties of Infrared Transmitting Materials

    Science.gov (United States)

    1978-01-01

    Theory of the Elasticity," 4th Edition, Dover Publ. Co., New York, N.Y., 1944. Marriott, J. B., and G. Rowden, "The Erosion of a Cobalt - Chromium Alloy...alumina (A1203), spinel (magnesium aluminate ), magnesia (MgO), yttria (Y203), as well as chemical vapor deposition (CVD) silicon carbide, CVD...known to be a problem. Because of their thermal and mechanical properties, alumina and magnesium aluminate (spinel) show, or can show, erosion

  10. Improvement of mechanical properties of chitosan film

    OpenAIRE

    Krkić, Nevena; Lazić, Vera; Šuput, Danijela

    2012-01-01

    This paper investigates the intensity of the influence which poly (ethylene oxide) and poly(ethylene glycol) additions have on the mechanical and structural properties of chitosan films. The films based on highly viscous and medium viscous chitosan were produced under laboratory conditions. Poly(ethylene oxide), with the average molecular weight of 100 000, and poly (ethylene glycol), with the average molecular weight of 400, were added to the films. The infrared spectrums of produced films w...

  11. Electrical properties of mechanically activated zinc oxide

    Directory of Open Access Journals (Sweden)

    Vojisavljević K.

    2006-01-01

    Full Text Available Microstructural properties of a commercial zinc oxide powder were modified by mechanical activation in a high-energy vibro-mill. The obtained powders were dry pressed and sintered at 1100°C for 2 h. The electrical properties of grain boundaries of obtained ZnO ceramics were studied using an ac impedance analyzer. For that purpose, the ac electrical response was measured in the temperature range from 23 to 240°C in order to determine the resistance and capacitance of grain boundaries. The activation energies of conduction were obtained using an Arrhenius equation. Donor densities were calculated from Mott-Schottky measurements. The influence of microstructure, types and concentrations of defects on electrical properties was discussed.

  12. Results of investigations regarding the physical and mechanical properties of the martensitic 9% Cr steel EUROFER '97; Ergebnisse von Charakterisierungsuntersuchungen zu physikalischen und mechanischen Eigenschaften des martensitischen 9% Cr-Stahles EUROFER '97

    Energy Technology Data Exchange (ETDEWEB)

    Schirra, M.; Falkenstein, A.; Graf, P.; Heger, S.; Kempe, H.; Lindau, R.; Zimmermann, H.

    2002-04-01

    Following the history of the development activities from conventional martensitic 12% Cr steel, MANET and OPTIFER up to low-activated EUROFER (RAFM steel), the results obtained from experiments on rods of 100 mm diameter and plates of 14 mm shall be presented for a basic characterization. The physical and mechanical properties shall be compared with those of OPTIFER-1W and the F82H-mod 2% W steel. To determine the conversion behavior, a continuous cct diagram was plotted. Hardening experiments in the temperature range of 850 - 1120 C illustrated the range of maximum hardness as well as grain size development. The notch impact behavior was described for various heat treatments and sample types at test temperatures ranging from +60 to -100 C. Tensile strengths were determined for various heat treatments at temperatures ranging from room temperature to 700 C. Aging due to a long-term heat treatment was investigated by means of stabilization annealing experiments. Creep rupture strength and creeping were investigated in the temperature range of 450 - 650 C. So far, a duration of up to about 15 000 h has been covered by the experiments. (orig.)

  13. Mechanical, Thermal and Dynamic Mechanical Properties of PP/GF/xGnP Nanocomposites

    Science.gov (United States)

    Ashenai Ghasemi, F.; Ghorbani, A.; Ghasemi, I.

    2017-03-01

    The mechanical, thermal, and dynamic mechanical properties of ternary nanocomposites based on polypropylene, short glass fibers, and exfoliated graphene nanoplatelets were studied. To investigate the mechanical properties, uniaxial tensile and Charpy impact tests were carried out. To study the crystallinity of the compositions, a DSC test was performed. A dynamic mechanical analysis was used to characterize the storage modulus and loss factor (tan δ). The morphology of the composites was studied by a scanning electron microscope (SEM). The results obtained are presented in tables and graphics.

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

    Energy Technology Data Exchange (ETDEWEB)

    D. Rigby

    2004-11-10

    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).

  15. Mechanical properties of canine patella-ligament-tibia segment.

    Science.gov (United States)

    Biskup, Jeffery; Freeman, Andy; Camisa, Will; Innes, John; Conzemius, Michael

    2014-02-01

    To test the ex vivo mechanical properties of canine patella-ligament-tibia (PLT) segment and establish the relationship between donor size and PLT dimensions to the mechanical properties of PLT grafts. Ex vivo mechanical testing study. Canine PLT segments (n = 21 dogs; 42 PLT). Morphometric measurements of PLT segments were taken from computed tomography (CT) images and compared with results obtained using calipers. PLT were tested to failure at a rate of 100% length/s. Mechanical properties and failure mode were recorded. PLT width and thickness (P 25 kg were similar to those reported for the cranial cruciate ligament (CCL) suggesting that the PLT may be a suitable allograft for CCL replacement. © Copyright 2013 by The American College of Veterinary Surgeons.

  16. Aggregate of nanoparticles: rheological and mechanical properties

    Directory of Open Access Journals (Sweden)

    Wang Yu

    2011-01-01

    Full Text Available Abstract The understanding of the rheological and mechanical properties of nanoparticle aggregates is important for the application of nanofillers in nanocompoistes. In this work, we report a rheological study on the rheological and mechanical properties of nano-silica agglomerates in the form of gel network mainly constructed by hydrogen bonds. The elastic model for rubber is modified to analyze the elastic behavior of the agglomerates. By this modified elastic model, the size of the network mesh can be estimated by the elastic modulus of the network which can be easily obtained by rheology. The stress to destroy the aggregates, i.e., the yield stress (σy , and the elastic modulus (G' of the network are found to be depended on the concentration of nano-silica (ϕ, wt.% with the power of 4.02 and 3.83, respectively. Via this concentration dependent behavior, we can extrapolate two important mechanical parameters for the agglomerates in a dense packing state (ϕ = 1: the shear modulus and the yield stress. Under large deformation (continuous shear flow, the network structure of the aggregates will experience destruction and reconstruction, which gives rise to fluctuations in the viscosity and a shear-thinning behavior.

  17. Tribological properties and lubricating mechanisms of Cu nanoparticles in lubricant

    Institute of Scientific and Technical Information of China (English)

    YU He-long; XU Yi; SHI Pei-jing; XU Bin-shi; WANG Xiao-li; LIU Qian

    2008-01-01

    Wear and friction properties of surface modified Cu nanoparticles as 50CC oil additive were studied.The effect of temperature on tribological properties of Cu nanoparticles was investigated on a four-ball tester.The morphologies,typical element distribution and chemical states of the worn surfaces were characterized by SEM,EDS and XPS,respectively.In order to further investigate the tribological mechanism of Cu nanoparticles,a nano-indentation tester was utilized to measure the micro mechanical Properties of the worn surface.The results indicate that the higher me oil temperature applied,the better the tribological properties of Cu nanoparticles are.It can be inferred that a thin copper protective film with lower elastic modulus and hardness is formed on the wom surface,which results in the good tribological performances of Cu nanoparticles,especially when the Oil temperature is higher.

  18. Design of monoliths through their mechanical properties.

    Science.gov (United States)

    Podgornik, Aleš; Savnik, Aleš; Jančar, Janez; Krajnc, Nika Lendero

    2014-03-14

    Chromatographic monoliths have several interesting properties making them attractive supports for analytics but also for purification, especially of large biomolecules and bioassemblies. Although many of monolith features were thoroughly investigated, there is no data available to predict how monolith mechanical properties affect its chromatographic performance. In this work, we investigated the effect of porosity, pore size and chemical modification on methacrylate monolith compression modulus. While a linear correlation between pore size and compression modulus was found, the effect of porosity was highly exponential. Through these correlations it was concluded that chemical modification affects monolith porosity without changing the monolith skeleton integrity. Mathematical model to describe the change of monolith permeability as a function of monolith compression modulus was derived and successfully validated for monoliths of different geometries and pore sizes. It enables the prediction of pressure drop increase due to monolith compressibility for any monolith structural characteristics, such as geometry, porosity, pore size or mobile phase properties like viscosity or flow rate, based solely on the data of compression modulus and structural data of non-compressed monolith. Furthermore, it enables simple determination of monolith pore size at which monolith compressibility is the smallest and the most robust performance is expected. Data of monolith compression modulus in combination with developed mathematical model can therefore be used for the prediction of monolith permeability during its implementation but also to accelerate the design of novel chromatographic monoliths with desired hydrodynamic properties for particular application.

  19. 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.

  20. Mechanical properties of micron and nanodimentional metal films

    Directory of Open Access Journals (Sweden)

    I.Yu. Protsenko

    2010-01-01

    Full Text Available The mechanical and strain resistivity properties data for bulk condensates and nanodimentional films at the elastic and plastic deformation was analyzed. The experimental results of strain resistivity properties of one-layer (Fe, Cr, Pd and Pt and two-layer (Fe/Cr, Cu/Cr and Pd/Fe films, in particular, dependence of the deformation at the transition from elastic to plastic deformation from thickness was presented.

  1. 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.

  2. Mechanical properties of crepe paper and chickpaper

    Directory of Open Access Journals (Sweden)

    Ľubomír KUBÍK

    2016-06-01

    Full Text Available The paper deals with the evaluation of the mechanical properties of the crepe paper and chickpaper. The thickness of crepe paper was 300 m with the surface mass 150 g*m-2 and chickpaper paper thickness was 100 m with the surface mass 40 g*m-2. Crepe paper and chickpaper are usually used for chicken breeding. Longitudinal and transversal tensile properties were studied. The tensile behavior was monitored on the motorized test stand ANDILOG STENTOR 1000 (Andilog Technologies, Vitrolles, France.There were measured the tensile properties as modulus of elasticity, maximal elongation, maximal tensile force, tensile strengths, tensile index and strain at break of the longitudinal and transversal samples by testing paper strips. Mean values of the maximal elongation b of longitudinal chickpaper samples were three times smaller than maximal elongation of transversal samples. Mean values of maximal tensile force Ft, tensile strength btensile indexwand maximal strain at break T of longitudinal chickpaper samples were two times smaller than maximal quantities of transversal samples. Mean values of the tensile modulus of elasticity of longitudinal and transversal chickpaper samples were almost equal. Chickpaper mechanical properties in tension were different in the longitudinal and transversal direction of the original paper surface. Mean values of the maximal elongation b and maximal strain at break T of longitudinal crepe paper samples were sixty times smaller than maximal elongation and maximal strain at break of transversal samples. Mean values of maximal tensile force Ft, tensile strength bandtensile indexwof longitudinal crepe paper samples were fourth times smaller than maximal quantities of transversal samples. Mean values of the tensile modulus of elasticity of longitudinal samples of crepe paper were thirty eight times smaller than values of transversal samples.

  3. Linking properties to microstructure through multiresolution mechanics

    Science.gov (United States)

    McVeigh, Cahal James

    The macroscale mechanical and physical properties of materials are inherently linked to the underlying microstructure. Traditional continuum mechanics theories have focused on approximating the heterogeneous microstructure as a continuum, which is conducive to a partial differential equation mathematical description. Although this makes large scale simulation of material much more efficient than modeling the detailed microstructure, the relationship between microstructure and macroscale properties becomes unclear. In order to perform computational materials design, material models must clearly relate the key underlying microstructural parameters (cause) to macroscale properties (effect). In this thesis, microstructure evolution and instability events are related to macroscale mechanical properties through a new multiresolution continuum analysis approach. The multiresolution nature of this theory allows prediction of the evolving magnitude and scale of deformation as a direct function of the changing microstructure. This is achieved via a two-pronged approach: (a) Constitutive models which track evolving microstructure are developed and calibrated to direct numerical simulations (DNS) of the microstructure. (b) The conventional homogenized continuum equations of motion are extended via a virtual power approach to include extra coupled microscale stresses and stress couples which are active at each characteristic length scale within the microstructure. The multiresolution approach is applied to model the fracture toughness of a cemented carbide, failure of a steel alloy under quasi-static loading conditions and the initiation and velocity of adiabatic shear bands under high speed dynamic loading. In each case the multiresolution analysis predicts the important scale effects which control the macroscale material response. The strain fields predicted in the multiresolution continuum analyses compare well to those observed in direct numerical simulations of the

  4. 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.

  5. Passive mechanical properties of ovine rumen tissue

    Science.gov (United States)

    Waite, Stephen J.; Cater, John E.; Walker, Cameron G.; Amirapu, Satya; Waghorn, Garry C.; Suresh, Vinod

    2016-05-01

    Mechanical and structural properties of ovine rumen tissue have been determined using uniaxial tensile testing of tissue from four animals at five rumen locations and two orientations. Animal and orientation did not have a significant effect on the stress-strain response, but there was a significant difference between rumen locations. Histological studies showed two orthogonal muscle layers in all regions except the reticulum, which has a more isotropic structure. A quasi-linear viscoelastic model was fitted to the relaxation stage for each region. Model predictions of the ramp stage had RMS errors of 13-24% and were within the range of the experimental data.

  6. Photochromic properties and reaction mechanism of naphthopyran

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    The photochromic properties and reaction mechanism of title compounds have been examined with steady method on compounds 3-phenyl-3-[3-methylbenzothiophene-2-yl]-3H- naphtho[2,1-b]pyran (1) and 3-phenyl-3-[benzofuran-2-yl]-3H-naphtho[2,1-b]pyran (2) and nanosecond laser flash photolysis techniques on compound 3-phenyl-3-[1,2-dimethylindol-3-yl]- 3H-naphtho[2,1-b]pyran (3). The influence of oxygen on transient spectra and decay kinetics of compound 3 has been investigated. Both excited singlet state and triplet state are involved in the photochromic mechanism of compound 3. The influence of molecular structure on photochromic behavior has been studied also. Decay kinetics indicated that the lifetime of colored forms of 1 and 2 were several orders of magnitude longer than that of 3.

  7. Photochromic properties and reaction mechanism of naphthopyran

    Institute of Scientific and Technical Information of China (English)

    潘桂兰; 魏景强; 朱爱平; 明阳福; 樊美公; 姚思德

    2001-01-01

    The photochromic properties and reaction mechanism of title compounds have been examined with steady method on compounds 3-phenyl-3-[3-methylbenzothiophene-2-yl]-3H-naphtho[2,1-b]pyran (1) and 3-phenyl-3-[benzofuran-2-yl]-3H-naphtho[2,1-b]pyran (2) and nanosecond laser flash photolysis techniques on compound 3-phenyl-3-[1,2-dimethylindol-3-yl]-3H-naphtho[2,1-b]pyran (3). The influence of oxygen on transient spectra and decay kinetics of compound 3 has been investigated. Both excited singlet state and triplet state are involved in the photochromic mechanism of compound 3. The influence of molecular structure on photochromic behavior has been studied also. Decay kinetics indicated that the lifetime of colored forms of 1 and 2 were several orders of magnitude longer than that of 3.

  8. Influence of Moisture on Mechanical Properties of Cellulose Insulation Paper

    Science.gov (United States)

    Wang, Y. Y.; Tian, M.; Xu, H. X.; Fan, P.

    2014-01-01

    This paper aims to investigate the impact of moisture on mechanical properties of insulation paper. According to the molecular modeling approach proposed by Theodorou, the amorphous cellulose models of insulation paper with different moisture contents were built up to calculate mechanical parameters and hydrogen bond networks. And relevant conclusions could be drawn through further analysis on these calculation results: water molecules can destroy hydrogen bond network between the neighboring cellulose molecules, which might be responsible for the significant decrease of Young's modulus and other mechanical parameters, while no appreciable effect of intramolecular hydrogen bonds on mechanical properties was detected. Thus tensile tests were also carried out to study the moisture influence on the Young's modulus, by which the result of the simulation was approved.

  9. Laser welding of polymers, compatibility and mechanical properties

    DEFF Research Database (Denmark)

    Nielsen, Steen Erik; Strange, Marianne; Kristensen, Jens Klæstrup

    2013-01-01

    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....... There is an increasing industrial interest in joining dissimilar polymers. To overcome the challenges involved increased focus is set on the understanding of joining mechanisms, morphology and molecular structure behavior. Also the understanding of resulting mechanical and thermal properties is presently subject...... 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...

  10. Mechanical Properties Prediction of the Mechanical Clinching Joints Based on Genetic Algorithm and BP Neural Network

    Institute of Scientific and Technical Information of China (English)

    LONG Jiangqi; LAN Fengchong; CHEN Jiqing; YU Ping

    2009-01-01

    For optimal design of mechanical clinching steel-aluminum joints, the back propagation (BP) neural network is used to research the mapping relationship between joining technique parameters including sheet thickness, sheet hardness, joint bottom diameter etc., and mechanical properties of shearing and peeling in order to investigate joining technology between various material plates in the steel-aluminum hybrid structure car body. Genetic algorithm (GA) is adopted to optimize the back-propagation neural network connection weights. The training and validating samples are made by the BTM(R) Tog-L-Loc system with different technologic parameters. The training samples' parameters and the corresponding joints' mechanical properties are supplied to the artificial neural network (ANN) for training. The validating samples' experimental data is used for checking up the prediction outputs. The calculation results show that GA can improve the model's prediction precision and generalization ability of BP neural network. The comparative analysis between the experimental data and the prediction outputs shows that ANN prediction models after training can effectively predict the mechanical properties of mechanical clinching joints and prove the feasibility and reliability of the intelligent neural networks system when used in the mechanical properties prediction of mechanical clinching joints. The prediction results can be used for a reference in the design of mechanical clinching steel-aluminum joints.

  11. Measurements and Characterizations of Mechanical Properties of Human Skins

    Science.gov (United States)

    Song, Han Wook; Park, Yon Kyu

    A skin is an indispensible organ for humans because it contributes to metabolism using its own biochemical functions and protects the human body from external stimuli. Recently, mechanical properties such as a thickness, a friction and an elastic coefficient have been used as a decision index in the skin physiology and in the skin care market due to the increased awareness of wellbeing issues. In addition, the use of mechanical properties is known to have good discrimination ability in the classification of human constitutions, which are used in the field of an alternative medicine. In this study, a system that measures mechanical properties such as a friction and an elastic coefficient is designed. The equipment consists of a load cell type (manufactured by the authors) for the measurements of a friction coefficient, a decompression tube for the measurement of an elastic coefficient. Using the proposed system, the mechanical properties of human skins from different constitutions were compared, and the relative repeatability error for measurements of mechanical properties was determined to be less than 2%. Combining the inspection results of medical doctors in the field of an alternative medicine, we could conclude that the proposed system might be applicable to a quantitative constitutional diagnosis between human constitutions within an acceptable level of uncertainty.

  12. 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.

  13. Mechanical properties of rice husk flour reinforced epoxy biocomposite

    Directory of Open Access Journals (Sweden)

    Neeraj Bisht

    2015-06-01

    Full Text Available A bio-composite reinforced with rice husk flour in epoxy resin has been developed. The effect of fibre treatment and weight percentage of rice husk on the mechanical properties was studied and compared with wood dust reinforced epoxy composite. It was observed that addition of rice husk as filler is detrimental to almost all the mechanical properties. About 51% and 26.8% decrease in ultimate strength and Young’s Modulus for 40 wt% untreated rice husk reinforcement was observed. The corresponding decrease in flexural strength and flexural modulus was 51%. Similar trend was also observed in hardness and impact strength. However the mechanical properties of rice husk reinforced biocomposites are found to be superior than wood dust reinforced epoxy composite. SEM microscopy was also done to corroborate the results.

  14. Coronal Jet Plasma Properties and Acceleration Mechanisms

    Science.gov (United States)

    Farid, Samaiyah; Reeves, Kathy; Savcheva, Antonia; Soto, Natalia

    2017-08-01

    Coronal jets are transient eruptions of plasma typically characterized by aprominent long spire and a bright base, and sometimes accompanied by a small filament. Jets are thought to be produced by magnetic reconnection when small-scale bipolar magnetic fields emerge into an overlying coronal field or move into a locally unipolar region. Coronal jets are commonly divided into two categories: standard jets and blowout jets, and are found in both quiet and active regions. The plasma properties of jets vary across type and location, therefore understanding the underlying acceleration mechanisms are difficult to pin down. In this work, we examine both blow-out and standard jets using high resolution multi-wavelength data. Although reconnection is commonly accepted as the primary acceleration mechanism, we also consider the contribution chromospheric evaporation to jet formation. We use seven coronal channels from SDO/AIA , Hinode/XRT Be-thin and IRIS slit-jaw data. In addition, we separate the Fe-XVIII line from the SDO/94Å channel. We calculate plasma properties including velocity, Alfven speed, and density as a function of wavelength and Differential Emission Measure (DEM). Finally, we explore the magnetic topology of the jets using Coronal Modeling System (CMS) to construct potential and non-linear force free models based on the flux rope insertion method.

  15. Mechanical properties of nanoporous graphene membrane

    Science.gov (United States)

    Liu, Yilun; Chen, Xi

    2014-01-01

    Nanoporous graphene holds great promise in the application of filtration such as seawater desalination, gas separation, and ionic channels. In this paper, we study the mechanical properties of nanoporous graphene with different size, shape, and density of nanopore. The strength decreases as the size and porosity of the nanopore increases. However, the rough edges of the nanopore has significant influence to the strength where the blunt tip perpendicular to the loading direction has higher strength. The effective tensile modulus is only determined by porosity of the nanopore as ΔE ˜ -p0.64, while the strength is determined by the size, shape, and porosity of the nanopore, for the same type of nanopore the strength scales with the porosity as Δσs ˜ -p. In contrast, the effective fracture strain increases as porosity increases for small and moderate porosities. The work is a first study of the relation between mechanical properties and porosity of nanoporous graphene and is helpful to the design of high performance nanoporous graphene membrane.

  16. Finite Element Simulation of the Mechanical Properties of Mineralized Biomaterials

    Science.gov (United States)

    Yuan, Fang

    Mineralized biomaterials are natural composite materials with both biomineral and biopolymer phases. They have attracted intense attention in the past decades, due to their outstanding mechanical properties and great potential as future materials. Such exceptional properties are believed to be attributed to their complex structures. Therefore, two different mineralized biomaterials (bone and sea urchin spine) were studied mainly by the finite element method and their structure-mechanical properties relationships were investigated. The research on bone was performed with a bottom-up approach. We focused on the nanoscale level structure-properties relationship first: the models of mineralized collagen fibril, consisting of hydroxyapatite platelets aligned within a collagen matrix, were created and the importance of the parameters defining its structure and constituent properties was evaluated. With the elastic model well established, the long-term mechanical behavior at nanoscale level was studied. The viscoelastic properties of undamaged collagen phase were deduced from low-irradiation-dosage creep measurements, then different damage scenarios were evaluated to explain the evolution of phase strains with larger irradiation dosage. The higher level structure-properties relationship of bone was simulated by two different approaches: 1) Assuming the macroscopic composite strain was comparable to nanoscale fibrillar strain, then based on nanoscale model, the macroscopic distributions of nanoscale phase strains were investigated; 2) Considering the structural complexity of bone at several length scales, the effective properties from lower scales were applied as the input properties at higher scales, and the elastic properties at each level were investigated. The computational results were validated by experimental data obtained by synchrotron X-ray diffraction and show the mechanical properties of bone are greatly influenced by its structure. The research on sea urchin

  17. Study of UV fiber's mechanical properties

    Institute of Scientific and Technical Information of China (English)

    Feng TU; Xinwei QIAN; Deming LIU; Shuqiang ZHANG; Jie LUO; Tao DENG; Chen YANG; Jiangtao GUO

    2009-01-01

    A number of spectroscopic techniques make use of ultra violet (UV) absorbance and luminescence measurements to characterize materials, for use in medical/pharmaceutical applications, for forensic and sensor applications, and for remote detection or monitoring,especially for hazardous environments.Furthermore, many high-power applications in medicine and industry are looking forward to using UV wavelengths.The UV fiber's mechanical reliability has become one of the most crucial performances with longer length fiber being used.This paper reviews the researched evolvement of the normal single mode fiber's mechanical reliability.Based on the standard measure method of the normal fiber, the mechanical reliability of the UV fiber has been researched.The measurement results show the difference of mechanical reliability between the different doping composition UV fibers.

  18. Mechanical Properties of Degraded PMR-15 Resin

    Science.gov (United States)

    Tsuji, Luis C.

    2000-01-01

    Thermo-oxidative aging produces a nonuniform degradation state in PMR-15 resin. A surface layer, usually attributed to oxidative degradation, forms. This surface layer has different properties from the inner material. A set of material tests was designed to separate the properties of the oxidized surface layer from the properties of interior material. Test specimens were aged at 316 C in either air or nitrogen, for durations of up to 800 hr. The thickness of the oxidized surface layer in air aged specimens, and the shrinkage and coefficient of thermal expansion (CTE) of nitrogen aged specimens were measured directly. The nitrogen-aged specimens were assumed to have the same properties as the interior material in the air-aged specimens. Four-point-bend tests were performed to determine modulus of both the oxidized surface layer and the interior material. Bimaterial strip specimens consisting of oxidized surface material and unoxidized interior material were constructed and used to determine surface layer shrinkage and CTE. Results confirm that the surface layer and core materials have substantially different properties.

  19. 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...

  20. Role of mismatch in mechanical properties in cancer cell migration

    Science.gov (United States)

    Butcher, Julian; Das, Moumita

    2014-03-01

    Recent experiments suggest that the mechanical stiffness of cells and their interaction with their surroundings undergo remarkable changes during tumor progression. An intriguing experimental result in this area suggests that the mismatch in the elasticity and adhesive properties between cancer cells and cells that have not yet transformed may lead to enhanced cancer cell motility in a binary cell population. Motivated by this, we study the mechanical response and dynamics of a binary system of active and deformable particles using Langevin Dynamics simulations. We characterize their motility by studying particle trajectories, mean square displacements and correlation functions. Our study may provide an understanding of the interplay of mechanical and statistical mechanical properties underlying the enhanced motility of cancer cells during metastasis. This work was partially supported by a D-RIG grant from the College of Science at Rochester Institute of Technology.

  1. New Results on Quantum Property Testing

    CERN Document Server

    Chakraborty, Sourav; Matsliah, Arie; de Wolf, Ronald

    2010-01-01

    We present several new examples of speed-ups obtainable by quantum algorithms in the context of property testing. First, motivated by sampling algorithms, we consider probability distributions given in the form of an oracle $f:[n]\\to[m]$. Here the probability $\\PP_f(j)$ of an outcome $j\\in[m]$ is the fraction of its domain that $f$ maps to $j$. We give quantum algorithms for testing whether two such distributions are identical or $\\epsilon$-far in $L_1$-norm. Recently, Bravyi, Hassidim, and Harrow~\\cite{BHH10} showed that if $\\PP_f$ and $\\PP_g$ are both unknown (i.e., given by oracles $f$ and $g$), then this testing can be done in roughly $\\sqrt{m}$ quantum queries to the functions. We consider the case where the second distribution is known, and show that testing can be done with roughly $m^{1/3}$ quantum queries, which we prove to be essentially optimal. In contrast, it is known that classical testing algorithms need about $m^{2/3}$ queries in the unknown-unknown case and about $\\sqrt{m}$ queries in the kno...

  2. The effect of composition on mechanical properties of brushite cements.

    Science.gov (United States)

    Engstrand, Johanna; Persson, Cecilia; Engqvist, Håkan

    2014-01-01

    Due to a fast setting reaction, good biological properties, and easily available starting materials, there has been extensive research within the field of brushite cements as bone replacing material. However, the fast setting of brushite cement gives them intrinsically low mechanical properties due to the poor crystal compaction during setting. To improve this, many additives such as citric acid, pyrophosphates, and glycolic acid have been added to the cement paste to retard the crystal growth. Furthermore, the incorporation of a filler material could improve the mechanical properties when used in the correct amounts. In this study, the effect of the addition of the two retardants, disodium dihydrogen pyrophosphate and citric acid, together with the addition of β-TCP filler particles, on the mechanical properties of a brushite cement was investigated. The results showed that the addition of low amounts of a filler (up to 10%) can have large effects on the mechanical properties. Furthermore, the addition of citric acid to the liquid phase makes it possible to use lower liquid-to-powder ratios (L/P), which strongly affects the strength of the cements. The maximal compressive strength (41.8MPa) was found for a composition with a molar ratio of 45:55 between monocalcium phosphate monohydrate and beta-tricalcium phosphate, an L/P of 0.25ml/g and a citric acid concentration of 0.5M in the liquid phase.

  3. Investigation of mechanical properties of cryogenically treated music wire

    Science.gov (United States)

    Heptonstall, A.; Waller, M.; Robertson, N. A.

    2015-08-01

    It has been reported that treating music wire (high carbon steel wire) by cooling to cryogenic temperatures can enhance its mechanical properties with particular reference to those properties important for musical performance. We use such wire for suspending many of the optics in Advanced LIGO, the upgrade to LIGO—the Laser Interferometric Gravitational-Wave Observatory. Two properties that particularly interest us are mechanical loss and breaking strength. A decrease in mechanical loss would directly reduce the thermal noise associated with the suspension, thus enhancing the noise performance of mirror suspensions within the detector. An increase in strength could allow thinner wire to be safely used, which would enhance the dilution factor of the suspension, again leading to lower suspension thermal noise. In this article, we describe the results of an investigation into some of the mechanical properties of music wire, comparing untreated wire with the same wire which has been cryogenically treated. For the samples we studied, we conclude that there is no significant difference in the properties of interest for application in gravitational wave detectors.

  4. Environmental properties set cell mechanics and morphology

    Science.gov (United States)

    Janmey, Paul

    2012-02-01

    Many cell types are sensitive to mechanical signals that are produced either by application of exogenous force to their surfaces, or by the resistance that their surroundings place on forces generated by the cells themselves. Cell morphology, motility, proliferation, and protein expression all change in response to substrate stiffness. Changing the elastic moduli of substrates alters the formation of focal adhesions, the assembly of actin filaments into bundles, and the stability of intermediate filaments. The range of stiffness over which different primary cell types respond can vary over a wide range and generally reflects the elastic modulus of the tissue from which these cells were isolated. Mechanosensing depends on the type of adhesion receptor by which the cell binds, and therefore on both the molecular composition of the extracellular matrix and the nature of its link to the cytoskeleton. Many cell types can alter their own stiffness to match that of the substrate to which they adhere. The maximal elastic modulus that cells such as fibroblasts can attain is similar to that of crosslinked actin networks at the concentrations in the cell cortex. The precise mechanisms of mechanosensing are not well defined, but they presumably require an elastic connection between cell and substrate, mediated by transmembrane proteins. The viscoelastic properties of different extracellular matrices and cytoskeletal elements strongly influence the response of cells to mechanical signals, and the unusual non-linear elasticity of many biopolymer gels, characterized by strain-stiffening, leads to novel mechanisms by which cells alter their stiffness by engagement of molecular motors that produce internal stresses. Cell cortical elasticity is dominated by cytoskeletal polymer networks and can be modulated by internal tension. Simultaneous control of substrate stiffness and adhesive patterns suggests that stiffness sensing occurs on a length scale much larger than single molecular

  5. Mechanical properties of Municipal Solid Waste by SDMT

    Energy Technology Data Exchange (ETDEWEB)

    Castelli, Francesco, E-mail: francesco.castelli@unikore.it [Geotechnical Engineering, Faculty of Engineering and Architecture, Kore University of Enna, 94100 Enna (Italy); Maugeri, Michele [Geotechnical Engineering, Department of Civil and Environmental Engineering, University of Catania, 95125 Catania (Italy)

    2014-02-15

    Highlights: • The adoption of the SDMT for the measurements of MSW properties is proposed. • A comparison between SDMT results and laboratory tests was carried out. • A good reliability has been found in deriving waste properties by SDMT. • Results seems to be promising for the friction angle and Young’s modulus evaluation. - Abstract: In the paper the results of a geotechnical investigation carried on Municipal Solid Waste (MSW) materials retrieved from the “Cozzo Vuturo” landfill in the Enna area (Sicily, Italy) are reported and analyzed. Mechanical properties were determined both by in situ and laboratory large-scale one dimensional compression tests. While among in situ tests, Dilatomer Marchetti Tests (DMT) is used widely in measuring soil properties, the adoption of the DMT for the measurements of MSW properties has not often been documented in literature. To validate its applicability for the estimation of MSW properties, a comparison between the seismic dilatometer (SDMT) results and the waste properties evaluated by laboratory tests was carried out. Parameters for “fresh” and “degraded waste” have been evaluated. These preliminary results seems to be promising as concerns the assessment of the friction angle of waste and the evaluation of the S-wave in terms of shear wave velocity. Further studies are certainly required to obtain more representative values of the elastic parameters according to the SDMT measurements.

  6. Characterization of High Temperature Mechanical Properties Using Laser Ultrasound

    Energy Technology Data Exchange (ETDEWEB)

    David Hurley; Stephen Reese; Farhad Farzbod; Rory Kennedy

    2012-05-01

    Mechanical properties are controlled to a large degree by defect structures such as dislocations and grain boundaries. These microstructural features involve a perturbation of the perfect crystal lattice (i.e. strain fields). Viewed in this context, high frequency strain waves (i.e. ultrasound) provide a natural choice to study microstructure mediated mechanical properties. In this presentation we use laser ultrasound to probe mechanical properties of materials. This approach utilizes lasers to excite and detect ultrasonic waves, and as a consequence has unique advantages over other methods—it is noncontacting, requires no couplant or invasive sample preparation (other than that used in metallurgical analysis), and has the demonstrated capability to probe microstructure on a micron scale. Laser techniques are highly reproducible enabling sophisticated, microstructurally informed data analysis. Since light is being used for generation and detection of the ultrasonic wave, the specimen being examined is not mechanically coupled to the transducer. As a result, laser ultrasound can be carried out remotely, an especially attractive characteristic for in situ measurements in severe environments. Several examples involving laser ultrasound to measure mechanical properties in high temperature environments will be presented. Emphasis will be place on understanding the role of grain microstructure.

  7. Mechanical Properties of Sheared Wet Granular Piles

    Science.gov (United States)

    Seemann, Ralf; Schaber, Marc; Karmakar, Somnath; Hippler, Anna-Lena; Scheel, Mario; di Michiel, Marco; Brinkmann, Martin

    2015-03-01

    The mechanical properties of dry and wet granulates are explored when being sheared with a parabolic profile at constant shear volume. The dissipated energy increase linearly with external pressure both for a wet and a dry granulate. However, the dissipated energy for wet a granulate has a finite value for the limiting case of vanishing external pressure and increases slower with external pressure compared to the dry granulate. Using a down sized version of the shear cell the reorganization of a granulate and liquid is additionally imaged in real time using x-ray micro-tomography. With the insight from x-ray tomography the contribution of the breaking capillary bridges to the dissipated energy can be analyzed. We could also shed light on the influence of dilatation effects on the dissipated energy upon inverting the shear direction.

  8. 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.

  9. 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.

  10. Results of fracture mechanics tests on PNC SUS 304 plate

    Energy Technology Data Exchange (ETDEWEB)

    Mills, W.J.; James, L.A.; Blackburn, L.D.

    1985-08-01

    PNC provided SUS 304 plate to be irradiated in FFTF at about 400/sup 0/C to a target fluence of 5 x 10/sup 21/ n/cm/sup 2/ (E > 0.1 MeV). The actual irradiation included two basically different exposure levels to assure that information would be available for the exposure of interest. After irradiation, tensile properties, fatigue-crack growth rates and J-integral fracture toughness response were determined. These same properties were also measured for the unirradiated material so radiation damage effects could be characterized. This report presents the results of this program. It is expected that these results would be applicable for detailed fracture analysis of reactor components. Recent advances in elastic-plastic fracture mechanics enable reasonably accurate predictions of failure conditions for flawed stainless steel components. Extensive research has focused on the development of J-integral-based engineering approach for assessing the load carrying capacity of low-strength, high-toughness structural materials. Furthermore, Kanninen, et al., have demonstrated that J-integral concepts can accurately predict the fracture response for full-scale cracked structures manufactured from Type 304 stainless steel.

  11. Mechanical property determination of high conductivity metals and alloys

    Science.gov (United States)

    Harrod, D. L.; Vandergrift, E.; France, L.

    1973-01-01

    Pertinent mechanical properties of three high conductivity metals and alloys; namely, vacuum hot pressed grade S-200E beryllium, OFHC copper and beryllium-copper alloy no. 10 were determined. These materials were selected based on their possible use in rocket thrust chamber and nozzle hardware. They were procured in a form and condition similar to that which might be ordered for actual hardware fabrication. The mechanical properties measured include (1) tension and compression stress strain curves at constant strain rate (2) tensile and compressive creep, (3) tensile and compressive stress-relaxation behavior and (4) elastic properties. Tests were conducted over the temperature range of from 75 F to 1600 F. The resulting data is presented in both graphical and tabular form.

  12. Effect of graphene on mechanical properties of cement mortars

    Institute of Scientific and Technical Information of China (English)

    曹明莉; 张会霞; 张聪

    2016-01-01

    Functionalized graphene nano-sheets (FGN) of 0.01%−0.05% (mass fraction) were added to produce FGN-cement composites in the form of mortars. Flow properties, mechanical properties and microstructure of the cementitious material were then investigated. The results indicate that the addition of FGN decreases the fluidity slightly and improves mechanical properties of cement-based composites significantly. The highest strength is obtained with FGN content of 0.02% where the flexural strength and compressive strength at 28 days are 12.917 MPa and 52.42 MPa, respectively. Besides, scanning electron micrographs show that FGN can regulate formation of massive compact cross-linking structures and thermo gravimetric analysis indicates that FGN can accelerate the hydration reaction to increase the function of the composite effectively.

  13. COMPUTER NUMERICAL SIMULATION OF MECHANICAL PROPERTIES OF TUNGSTEN HEAVY ALLOYS

    Institute of Scientific and Technical Information of China (English)

    1999-01-01

    A microstructure model of tungsten heavy alloys has been developed. On the basis of the model and several assumptions, the macro-mechanical properties of 90 W heavy alloy under quasi-static tensile deformation and the effects of microstructural parameters (mechanical properties of the matrix phase and tungsten content) on them have been analyzed by computer numerical simulation. The mechanical properties of the alloy have been found to be dependent on the mechanical parameters of the matrix phase. As the elastic modulus and yield strength of the matrix phase increase, the tensile strength of the alloy increases, while the elongation decreases. If the mechanical parameters except the tensile strength of the matrix phase are constant, both the tensile strength and the elongation of the alloy increase linearly with the increase of tensile strength of the matrix phase. The properties of the alloy are very sensitive to the hardening modulus of the matrix phase. As the hardening modulus increases, both the tensile strength and the elongation of the alloy exponentially decrease. The elongation of the alloys monotonically decreases with the increase of tungsten content, while the decrease of tensile strength is not monotonic. When the tungsten content < 85 %, the strength of tungsten heavy alloys increases with the increase of tungsten content, while decreases when the tungsten content >85 %. The maximum of tensile strength of the alloys appears at the tungsten content of 85 %. The results showed that the binder phase with a higher strength and a lower hardening modulus is advantageous to obtaining an optimum combination of mechanical properties of tungsten heavy alloys.

  14. Interspecific comparison of the mechanical properties of mussel byssus.

    Science.gov (United States)

    Brazee, Shanna L; Carrington, Emily

    2006-12-01

    Byssally tethered mussels are found in a variety of habitats, including rocky intertidal, salt marsh, subtidal, and hydrothermal vents. One key to the survival of mussels in these communities is a secure attachment, achieved by the production of byssal threads. Although many studies have detailed the unique biomechanical properties of byssal threads, only a few prevalent species have been examined. This study assesses the variation in the mechanical properties of byssus in a broad range of mussel species from diverse environments, including intertidal and subtidal Mytilus edulis, Modiolus modiolus, Geukensia demissa, Bathymodiolus thermophilus, and Dreissena polymorpha. A tensometer was used to measure quasi-static and dynamic mechanical properties of individual threads, and several aspects of morphology were quantified. The results indicate that thread mechanical properties vary among mussel species, and several novel properties were observed. For example, of the species examined, D. polymorpha threads were the strongest, stiffest, least resilient, and fastest to recover after partial deformation. Threads of M. modiolus were characterized by the presence of two distinct yield regions prior to tensile failure. This comparative study not only provides insight into the ecological limitations and evolution of mussels, but also suggests new models for the design of novel biomimetic polymers.

  15. 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.

  16. Sterilizing elastomeric chains without losing mechanical properties. Is it possible?

    Science.gov (United States)

    Pithon, Matheus Melo; Ferraz, Caio Souza; Rosa, Francine Cristina Silva; Rosa, Luciano Pereira

    2015-01-01

    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. PMID:26154462

  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. 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.

  19. On the mechanical properties of sintered metallic fibre structures

    Energy Technology Data Exchange (ETDEWEB)

    Veyhl, C., E-mail: Christoph.Veyhl@uon.edu.au [The University of Newcastle, School of Engineering, Centre for Mass and Thermal Transport in Engineering Materials, Callaghan, NSW 2308 (Australia); Fiedler, T., E-mail: Thomas.Fiedler@newcastle.edu.au [The University of Newcastle, School of Engineering, Centre for Mass and Thermal Transport in Engineering Materials, Callaghan, NSW 2308 (Australia); Jehring, U., E-mail: Ulrike.Jehring@ifam-dd.fraunhofer.de [Fraunhofer Institute for Manufacturing Technology and Advanced Materials, Branch Lab Dresden, 01277 Dresden, Winterbergstr. 28 (Germany); Andersen, O., E-mail: Olaf.Andersen@ifam-dd.fraunhofer.de [Fraunhofer Institute for Manufacturing Technology and Advanced Materials, Branch Lab Dresden, 01277 Dresden, Winterbergstr. 28 (Germany); Bernthaler, T., E-mail: Timo.Bernthaler@htw-aalen.de [University of Applied Sciences Aalen, Department of Surface Engineering and Materials Science, Faculty of Mechanical and Material Engineering, Beethovenstr. 1, 73430 Aalen (Germany); Belova, I.V., E-mail: Irina.Belova@newcastle.edu.au [The University of Newcastle, School of Engineering, Centre for Mass and Thermal Transport in Engineering Materials, Callaghan, NSW 2308 (Australia); Murch, G.E., E-mail: Graeme.Murch@newcastle.edu.au [The University of Newcastle, School of Engineering, Centre for Mass and Thermal Transport in Engineering Materials, Callaghan, NSW 2308 (Australia)

    2013-02-01

    The present study investigates mechanical properties of a novel sintered metallic fibre structure with different relative densities (i.e. 0.19, 0.27, and 0.46). The compressive mechanical properties Young's modulus, Poisson's ratio and 0.2% offset yield stress are determined. For this purpose, state of the art simulations are performed based on the real material structure using micro-computed tomography images. Computed results are compared with experimental uni-axial compression tests and good agreement between both methods is observed. Numerical analysis allows the investigation of directional dependence and mechanical anisotropy is observed to be governed by the fibre orientation. In addition, Young's modulus and 0.2% offset yield stress increase with rising relative density.

  20. Mechanical Properties of Materials with Nanometer Scale Microstructures

    Energy Technology Data Exchange (ETDEWEB)

    William D. Nix

    2004-10-31

    We have been engaged in research on the mechanical properties of materials with nanometer-scale microstructural dimensions. Our attention has been focused on studying the mechanical properties of thin films and interfaces and very small volumes of material. Because the dimensions of thin film samples are small (typically 1 mm in thickness, or less), specialized mechanical testing techniques based on nanoindentation, microbeam bending and dynamic vibration of micromachined structures have been developed and used. Here we report briefly on some of the results we have obtained over the past three years. We also give a summary of all of the dissertations, talks and publications completed on this grant during the past 15 years.

  1. 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.

  2. Short-range mechanical properties of skeletal and cardiac muscles.

    Science.gov (United States)

    Campbell, Kenneth S

    2010-01-01

    Striated muscles are disproportionately stiff for small movements. This facet of their behavior can be demonstrated by measuring the force produced when the muscle is stretched more than about 1% of its initial length. When this is done, it can be seen that force rises rapidly during the initial phases of the movement and much less rapidly during the latter stages of the stretch. Experiments performed using chemically permeabilized skeletal and cardiac muscles show that the initial stiffness of the preparations increases in proportion with isometric force as the free Ca²(+) concentration in the bathing solution is raised from a minimal to a saturating value. This is strong evidence that the short-range mechanical properties of activated muscle result from stretching myosin cross-bridges that are attached between the thick and thin filaments. Relaxed intact muscles also exhibit short-range mechanical properties but the molecular mechanisms underlying this behavior are less clear. This chapter summarizes some of the interesting features of short-range mechanical properties in different types of muscle preparation, describes some of the likely underlying mechanisms and discusses the potential physiological significance of the behavior.

  3. 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.

  4. Correlations Between Mechanical Properties of Steel Fiber Reinforced Concrete

    Directory of Open Access Journals (Sweden)

    Carrillo Julián

    2013-06-01

    Full Text Available Tension strength and post-cracking deformation capacities that exhibits steel fiber reinforced concrete (SFRC stimulate its use in elements governed by shear deformations. Aimed at developing design aids that promote the use of SFRC as web shear reinforcement of concrete walls for low-rise economic housing (LEH, an experimental study for describing the mechanical properties of SFRC was carried out. The experimental program included testing of 128 cylinder- and beam-type specimens. According to requirements specified by ACI-318, to thickness of walls used in LEH, and to results of previous studies, three Dramix fibers with length-diameter ratios of 55, 64 and 80 were selected. Fiber dosage was expressed in terms of the minimum fiber dosage specified by ACI-318 for replacing the minimum area of conventional shear reinforcement in beams (60 kg/m3. Therefore, five dosages were used: 0, 40, 45, 60 and 75 kg/m3. Mechanical properties of SFRC under compressive, tensile and flexural stresses were evaluated in this study. Based on trends of experimental results, numerical correlations for estimating both basic mechanical properties and properties that describe flexural performance of SFRC are proposed.

  5. Altered mechanical properties of the nucleus in disease.

    Science.gov (United States)

    Lombardi, Maria Lucia; Lammerding, Jan

    2010-01-01

    In eukaryotic cells, the nucleus is the largest and most rigid organelle. Therefore, its physical properties contribute critically to the biomechanical behavior of cells, e.g., during amoeboid migration or perfusion through narrow capillaries. Furthermore, it has been speculated that nuclear deformations could directly allow cells to sense mechanical stress, e.g., by modulating the access of specific transcription factors to their binding sites. Defects in nuclear mechanics have also been reported in a variety of muscular dystrophies caused by mutations in nuclear envelope proteins, indicating an important role in the maintenance of cells in mechanically stressed tissue. These findings have prompted the growing field of nuclear mechanics to develop advanced experimental methods to study the physical properties of the nucleus as a function of nuclear structure and organization, and to understand its role in physiology and disease. These experimental techniques include micropipette aspiration, atomic force microscopy of isolated nuclei, cellular strain and compression experiments, and microneedle manipulation of intact cells. These experiments have provided important insights into the mechanical behavior of the nucleus under physiological conditions, the distinct mechanical contributions of the nuclear lamina and interior, and how mutations in nuclear envelope proteins associated with a variety of human diseases can cause distinct alterations in the physical properties of the nucleus and contribute to the disease mechanism. Here, we provide a brief overview of the most common experimental techniques and their application and discuss the implication of their results on our current understanding of nuclear mechanics. Copyright (c) 2010 Elsevier Inc. All rights reserved.

  6. Extracting nanobelt mechanical properties from nanoindentation

    Science.gov (United States)

    Zhang, Yin

    2010-06-01

    A three-spring-in-series model is proposed for the nanobelt (NB) indentation test. Compared with the previous two-spring-in-series model, which considers the bending stiffness of atomic force microscope cantilever and the indenter/NB contact stiffness, this model adds a third spring of the NB/substrate contact stiffness. NB is highly flexural due to its large aspect ratio of length to thickness. The bending and lift-off of NB form a localized contact with substrate, which makes the Oliver-Pharr method [W. C. Oliver and G. M. Pharr, J. Mater. Res. 7, 1564 (1992)] and Sneddon method [I. N. Sneddon, Int. J. Eng. Sci. 3, 47 (1965)] inappropriate for NB indentation test. Because the NB/substrate deformation may have significant impact on the force-indentation depth data obtained in experiment, the two-spring-in-series model can lead to erroneous predictions on the NB mechanical properties. NB in indentation test can be susceptible to the adhesion influence because of its large surface area to volume ratio. NB/substrate contact and adhesion can have direct and significant impact on the interpretation of experimental data. Through the three-spring-in-series model, the influence of NB/substrate contact and adhesion is analyzed and methods of reducing such influence are also suggested.

  7. Mechanical properties of lattice grid composites

    Institute of Scientific and Technical Information of China (English)

    Hualin Fan; Daining Fang; Fengnian Jin

    2008-01-01

    An equivalent continuum method only considering the stretching deformation of struts was used to study the in-plane stiffness and strength of planar lattice grid composite materials. The initial yield equations of lattices were deduced. Initial yield surfaces were depicted separately in different 3D and 2D stress spaces. The failure envelope is a polyhedron in 3D spaces and a polygon in 2D spaces. Each plane or line of the failure envelope is corresponding to the yield or buckling of a typical bar row. For lattices with more than three bar rows, subsequent yield of the other bar rowafter initial yield made the lattice achieve greater limit strength. The importance of the buckling strength of the grids was strengthened while the grids were relative sparse. The integration model of the method was used to study the nonlinear mechanical properties of strain hardening grids. It was shown that the integration equation could accurately model the complete stress-strain curves of the grids within small deformations.

  8. Mechanical properties of a collagen fibril under simulated degradation.

    Science.gov (United States)

    Malaspina, David C; Szleifer, Igal; Dhaher, Yasin

    2017-11-01

    Collagen fibrils are a very important component in most of the connective tissue in humans. An important process associated with several physiological and pathological states is the degradation of collagen. Collagen degradation is usually mediated by enzymatic and non-enzymatic processes. In this work we use molecular dynamics simulations to study the influence of simulated degradation on the mechanical properties of the collagen fibril. We applied tensile stress to the collagen fiber at different stages of degradation. We compared the difference in the fibril mechanical priorities due the removal of enzymatic crosslink, surface degradation and volumetric degradation. As anticipated, our results indicated that, regardless of the degradation scenario, fibril mechanical properties is reduced. The type of degradation mechanism (crosslink, surface or volumetric) expressed differential effect on the change in the fibril stiffness. Our simulation results showed dramatic change in the fibril stiffness with a small amount of degradation. This suggests that the hierarchical structure of the fibril is a key component for the toughness and is very sensitive to changes in the organization of the fibril. The overall results are intended to provide a theoretical framework for the understanding the mechanical behavior of collagen fibrils under degradation. Copyright © 2017 Elsevier Ltd. All rights reserved.

  9. Structural and Mechanical Properties of Fluorinated SWCNTs: a DFT Study

    Directory of Open Access Journals (Sweden)

    I.K. Petrushenko

    2015-03-01

    Full Text Available This paper presents a study on structural and mechanical properties of a series of fluorinated armchair single-walled carbon nanotubes (SWCNTs by using density functional theory. At the PBE / SVP level, the data obtained compare well with experimental and theoretical studies. The results show that fluorination, in general, distort SWNCTs framework, but there exists the difference between ‘axial’ and ‘circumferential’ functionalization. It turns out that elastic properties diminish with increasing concentration of adsorbents, however, the fluorinated SWCNTs remain strong enough to be suitable for reinforcement of composites.

  10. On mechanical properties of planar flexure hinges of compliant mechanisms

    Directory of Open Access Journals (Sweden)

    F. Dirksen

    2011-06-01

    Full Text Available The synthesis of compliant mechanisms yield optimized topologies that combine several stiff parts with highly elastic flexure hinges. The hinges are often represented in finite element analysis by a single node (one-node hinge leaving doubts on the physical meaning as well as an uncertainty in the manufacturing process.

    To overcome this one-node hinge problem of optimized compliant mechanisms' topologies, one-node hinges need to be replaced by real flexure hinges providing desired deflection range and the ability to bear internal loads without failure. Therefore, several common types of planar flexure hinges with different geometries are characterized and categorized in this work providing a comprehensive guide with explicit analytical expressions to replace one-node hinges effectively.

    Analytical expressions on displacements, stresses, maximum elastic deformations, bending stiffness, center of rotation and first natural frequencies are derived in this work. Numerical simulations and experimental studies are performed validating the analytical results. More importance is given to practice-oriented flexure hinge types in terms of cost-saving manufacturability, i.e. circular notch type hinges and rectangular leaf type hinges.

  11. The mechanical and tribological properties of UHMWPE loaded ALN after mechanical activation for joint replacements.

    Science.gov (United States)

    Gong, Kemeng; Qu, Shuxin; Liu, Yumei; Wang, Jing; Zhang, Yongchao; Jiang, Chongxi; Shen, Ru

    2016-08-01

    Ultra-high molecular weight polyethylene (UHMWPE) loaded with alendronate sodium (ALN) has tremendous potential as an orthopeadic biomaterial for joint replacements. However, poor mechanical and tribological properties of UHMWPE-ALN are still obstacle for further application. The purpose of this study was to investigate the effect and mechanism of mechanical activation on mechanical and tribological properties of 1wt% ALN-loaded UHMWPE (UHMWPE-ALN-ma). In this study, tensile test, small punch test and reciprocating sliding wear test were applied to characterize the mechanical and tribological properties of UHMWPE-ALN-ma. Scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS) and Fourier transform infrared spectroscopy (FTIR) were employed to characterize UHMWPE-ALN-ma. Tensile test and small punch test showed that Young׳s modulus, tensile strength and work-to-failure (WTF) of UHMWPE-ALN-ma increased significantly compared to those of UHMWPE-ALN. The friction coefficients and wear factors of UHMWPE-ALN-ma both decreased significantly compared to those of UHMWPE-ALN. Mechanical activation obviously reduced type 1 (void) and type 2 (the disconnected and dislocated machining marks) fusion defects of UHMWPE-ALN-ma, which were revealed by SEM images of freeze fracture surfaces after etching and lateral surfaces of specimens after extension to fracture, respectively. It was attributed to peeled-off layers and chain scission of molecular chains of UHMWPE particles after mechanical activation, which were revealed by SEM images and FTIR spectra of UHMWPE-ALN-ma and UHMWPE-ALN, respectively. Moreover, EDS spectra revealed the more homogeneous distribution of ALN in UHMWPE-ALN-ma compared to that of UHMWPE-ALN. The present results showed that mechanical activation was a potential strategy to improve mechanical and tribological properties of UHMWPE-ALN-ma as an orthopeadic biomaterial for joint replacements.

  12. Microstructure characteristics and mechanical properties of rheocasting 7075 aluminum alloy

    Directory of Open Access Journals (Sweden)

    Yang Bin

    2013-09-01

    Full Text Available The microstructure characteristics and mechanical properties of 7075 aluminum alloy produced by a new rheoforming technique, under as-cast and optimized heat treatment conditions, were investigated. The present rheoforming combined the innovatively developed rheocasting process, named as ICSPC (inverted cone-shaped pouring channel process, and the existing HPDC (high pressure die casting process. The experimental results show that the ICSPC can be used to prepare high quality semi-solid slurry for the subsequent die casting. Compared with conventional HPDC process, the ICSPC process can improve the microstructures and mechanical properties of the cast tensile samples. An optimized heat treatment results in significant improvement in ultimate tensile strength. However, the ductility of the samples, both under as-cast and optimized heat treatment conditions, are relatively poor.

  13. Mechanical Properties of the TiAl IRIS Alloy

    Science.gov (United States)

    Voisin, Thomas; Monchoux, Jean-Philippe; Thomas, Marc; Deshayes, Christophe; Couret, Alain

    2016-12-01

    This paper presents a study of the mechanical properties at room and high temperature of the boron and tungsten containing IRIS alloy (Ti-48Al-2W-0.08B at. pct). This alloy was densified by Spark Plasma Sintering (SPS). The resultant microstructure consists of small lamellar colonies surrounded by γ regions containing B2 precipitates. Tensile tests are performed from room temperature to 1273 K (1000 °C). Creep properties are determined at 973 K (700 °C)/300 MPa, 1023 K (750 °C)/120 MPa, and 1023 K (750 °C)/200 MPa. The tensile strength and the creep resistance at high temperature are found to be very high compared to the data reported in the current literature while a plastic elongation of 1.6 pct is preserved at room temperature. A grain size dependence of both ductility and strength is highlighted at room temperature. The deformation mechanisms are studied by post-mortem analyses on deformed samples and by in situ straining experiments, both performed in a transmission electron microscope. In particular, a low mobility of non-screw segments of dislocations at room temperature and the activation of a mixed-climb mechanism during creep have been identified. The mechanical properties of this IRIS alloy processed by SPS are compared to those of other TiAl alloys developed for high-temperature structural applications as well as to those of similar tungsten containing alloys obtained by more conventional processing techniques. Finally, the relationships between mechanical properties and microstructural features together with the elementary deformation mechanisms are discussed.

  14. Physical and Mechanical Properties of Composites and Light Alloys Reinforced with Detonation Nanodiamonds

    Science.gov (United States)

    Sakovich, G. V.; Vorozhtsov, S. A.; Vorozhtsov, A. B.; Potekaev, A. I.; Kulkov, S. N.

    2016-07-01

    The influence of introduction of particles of detonation-synthesized nanodiamonds into composites and aluminum-base light alloys on their physical and mechanical properties is analyzed. The data on microstructure and physical and mechanical properties of composites and cast aluminum alloys reinforced with diamond nanoparticles are presented. The introduction of nanoparticles is shown to result in a significant improvement of the material properties.

  15. 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

  16. Microstructure characteristics and mechanical properties of rheocasting 7075 aluminum alloy

    OpenAIRE

    Yang Bin; Mao Weimin; Song Xiaojun

    2013-01-01

    The microstructure characteristics and mechanical properties of 7075 aluminum alloy produced by a new rheoforming technique, under as-cast and optimized heat treatment conditions, were investigated. The present rheoforming combined the innovatively developed rheocasting process, named as ICSPC (inverted cone-shaped pouring channel) process, and the existing HPDC (high pressure die casting) process. The experimental results show that the ICSPC can be used to prepare high quality semi-solid slu...

  17. Mechanical properties of several iron-nickel meteorites

    Energy Technology Data Exchange (ETDEWEB)

    Mulford, Roberta N [Los Alamos National Laboratory; El - Dasher, Bassem [LLNL

    2011-01-06

    Iron-nickel meteorites exhibit a unique lamellar microstructure, consisting of small regions with steep-iron-nickel composition gradients. The microstructure arises as a result of slow cooling in a planetary core or other large mass. The microstructure is further influenced by variable concentrations of other elements such as phosphorous which may have influenced cooling and phase separation. Mechanical properties of these composite structures have been investigated using Vickers and spherical indentation, x-ray fluorescence, and EBSD. Direct observation of mechanical properties in these highly structured materials provides a valuable supplement to bulk measurements, which frequently exhibit large variation in dynamic properties, even within a single sample. Previous studies of the mechanical properties of a typical iron-nickel meteorite, a Diablo Canyon specimen, indicated that the strength of the composite was higher by almost an order of magnitude than values obtained from laboratory-prepared specimens. This was ascribed to the extreme work-hardening evident in the EBSD measurements. Additional specimens from the Canyon Diablo fall (type IAB, coarse octahedrite) and several fine octahedrite meteorites, from the Muonionalusta meteorite (IVA) and Gibeon fall (IVA), have been examined to establish a range of error on the previously measured yield, to determine the extent to which deformation upon reentry contributes to yield, and to establish the degree to which the strength varies as a function of microstructure.

  18. 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.

  19. Unique microstructure and excellent mechanical properties of ADI

    Institute of Scientific and Technical Information of China (English)

    Jincheng Liu

    2006-01-01

    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 of extremely 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 austenite between the individual ferrite platelets 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 altemative materials.

  20. Evaluating mechanical properties and degradation of YTZP dental implants

    Energy Technology Data Exchange (ETDEWEB)

    Sevilla, Pablo, E-mail: pablo.sevilla@upc.edu [Biomaterials and Biomechanics Division, Department of Materials Science and Metallurgy, Technical University of Catalonia (Spain); Sandino, Clara; Arciniegas, Milena [Biomaterials and Biomechanics Division, Department of Materials Science and Metallurgy, Technical University of Catalonia (Spain); Martinez-Gomis, Jordi; Peraire, Maria [Department of Prosthodontics, Faculty of Odontology, University of Barcelona (Spain); Gil, Francisco Javier [Biomaterials and Biomechanics Division, Department of Materials Science and Metallurgy, Technical University of Catalonia (Spain)

    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.

  1. 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.

  2. Effect of hydrogen on mechanical properties of -titanium alloys

    Indian Academy of Sciences (India)

    H-J Christ; A Senemmar; M Decker; K Prüßner

    2003-06-01

    Conflicting opinions exist in the literature on the manner in which hydrogen influences the mechanical properties of -titanium alloys. This can be attributed to the -stabilizing effect of hydrogen in these materials leading to major changes in the microstructure as a result of hydrogen charging. The resulting (extrinsic) effect of hydrogen on the mechanical properties can possibly cover up the direct (intrinsic) influences. On the basis of experimentally determined thermodynamic and kinetic data regarding the interaction of hydrogen with -titanium alloys, hydrogen concentrations of up to 8 at.% were established in three commercial alloys by means of hydrogen charging from the gas phase. In order to separate intrinsic and extrinsic effects the charging was carried out during one step of the two-step heat treatment typical of metastable -titanium alloys, while the other step was performed in vacuum. The results on the single-phase condition represent the intrinsic hydrogen effect. Monotonic and cyclic strength increase at the expense of ductility with increasing hydrogen concentration. The brittle to ductile transition temperature shifts to higher values and the fatigue crack propagation threshold value decreases. The microstructure of the metastable, usually two-phase -titanium alloys is strongly affected by hydrogen, although the extent of this effect depends not only on the hydrogen concentration but also on the temperature of charging. This microstructural influence (extrinsic effect) changes the mechanical properties in the opposite direction as compared to the intrinsic hydrogen effect.

  3. Mechanical properties and stabilities of α-boron monolayers.

    Science.gov (United States)

    Peng, Qing; Han, Liang; Wen, Xiaodong; Liu, Sheng; Chen, Zhongfang; Lian, Jie; De, Suvranu

    2015-01-21

    We investigate the mechanical properties and stabilities of planar α-boron monolayers under various large strains using density functional theory (DFT). α-Boron has a high in-plane stiffness, about 2/3 of that of graphene, which suggests that α-boron is four times as strong as iron. Potential profiles and stress-strain curves indicate that a free standing α-boron monolayer can sustain large tensile strains, up to 0.12, 0.16, and 0.18 for armchair, zigzag, and biaxial deformations, respectively. Third, fourth, and fifth order elastic constants are indispensable for accurate modeling of the mechanical properties under strains larger than 0.02, 0.06, and 0.08 respectively. Second order elastic constants, including in-plane stiffness, are predicted to monotonically increase with pressure, while the trend of Poisson's ratio is reversed. The surface sound speeds of both the compressional and shear waves increase with pressure. The ratio of these two sound speeds increases with the increase of pressure and converges to a value of 2.5. Our results imply that α-boron monolayers are mechanically stable under various large strains and have advanced mechanical properties - high strength and high flexibility.

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

    African Journals Online (AJOL)

    Determination of Some Mechanical Properties of Almond Seed Related to Design of Food ... Nigerian Journal of Technological Development ... The determined engineering properties are vital for the design of postharvest handling and ...

  5. Mechanical and tribological properties of ion beam-processed surfaces

    Energy Technology Data Exchange (ETDEWEB)

    Kodali, Padma [Univ. of Maryland, College Park, MD (United States)

    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.

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

    Energy Technology Data Exchange (ETDEWEB)

    Zhang Xu; Liu Xiaoli; Sun Jialun [State Key Laboratory of Bioactive Materials, School of Physics, Nankai University, Tianjin 300073 (China); He Shuojie [State Key Laboratory of Bioactive Materials, School of Physics, Nankai University, Tianjin 300073 (China); Department of Physics, Pusan National University, Pusan (Korea, Republic of); Lee, Imshik [State Key Laboratory of Bioactive Materials, School of Physics, Nankai University, Tianjin 300073 (China)], E-mail: ilee@nankai.edu.cn2; Pak, Hyuk Kyu [Department of Physics, Pusan National University, Pusan (Korea, Republic of)

    2008-09-15

    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{sup *}. 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{sup *}-values disappears. It seems that the enhanced mechanical property was recover able under no additional mechanical stimulus.

  7. Mechanical and Microstructural Properties of PTFE/Al/W System

    Science.gov (United States)

    Cai, Jing; Jiang, Fengchun; Vecchio, Kenneth S.; Meyers, Marc A.; Nesterenko, Vitali F.

    2007-12-01

    Mechanical and microstructural properties of high density PTFE/Al/W composites consisting of PTFE matrix, aluminum and tungsten particles were investigated. Three types of samples having different porosities and particle sizes of W with an identical weight ratio between PTFE, Al and W were fabricated by Cold Isostatic Pressing. The quasi-static and Hopkinson Bar compression tests were employed to investigate the mechanical properties of these materials. The results demonstrated that the porous PTFE/Al/W composite samples containing fine W particles have higher quasi-static and dynamic fracture stresses than higher density PTFE/Al/W samples containing coarse W particles. ESEM micrographs revealed that deformation occurred mainly in the PTFE matrix while metal particles remain undeformed. We observed nano-fibers of PTFE caused by high strain rate deformation.

  8. Effect of Natural Fillers on Mechanical Properties of GFRP Composites

    Directory of Open Access Journals (Sweden)

    Vikas Dhawan

    2013-01-01

    Full Text Available Fiber reinforced plastics (FRPs have replaced conventional engineering materials in many areas, especially in the field of automobiles and household applications. With the increasing demand, various modifications are being incorporated in the conventional FRPs for specific applications in order to reduce costs and achieve the quality standards. The present research endeavor is an attempt to study the effect of natural fillers on the mechanical characteristics of FRPs. Rice husk, wheat husk, and coconut coir have been used as natural fillers in glass fiber reinforced plastics (GFRPs. In order to study the effect of matrix on the properties of GFRPs, polyester and epoxy resins have been used. It has been found that natural fillers provide better results in polyester-based composites. Amongst the natural fillers, in general, the composites with coconut coir have better mechanical properties as compared to the other fillers in glass/epoxy composites.

  9. Mechanical properties of hot rolled 2519 aluminum alloy plate

    Institute of Scientific and Technical Information of China (English)

    彭大暑; 陈险峰; 林启权; 张辉

    2003-01-01

    The effects of differences of temper on mechanical properties of T6, T7 and T8 plates of aluminum alloy 2519 were studied. The stress corrosion cracking(SCC) sensitivity was evaluated with parameters such as Kσ and Kδ.Tensile tests were divided into two groups: one was performed on tensile specimens without pre-corrosion, the other was performed on tensile specimens which were pre-corroded in 3.5%NaCl+1%H2O2 solution at 25 ℃.The results show that SCC resistance of alloy 2519 ranks in the order of T8>T7>T6 and the mechanical properties rank in the order of T6>T8>T7. SEM fractographs of the failed specimen show that the SCC sensitivity can be determined by the distribution of the second phase particles and size and the shape of grains in the alloy.

  10. Dynamic Mechanical Properties of Bio-Polymer Graphite Thin Films

    Science.gov (United States)

    Saddam Kamarudin, M.; Rus, Anika Zafiah M.; Munirah Abdullah, Nur; Abdullah, M. F. L.

    2017-08-01

    Waste cooking oil is used as the main substances in producing graphite biopolymer thin films. Biopolymer is produce from the reaction of bio-monomer and cross linker with the ratio of 2:1 and addition of graphite with an increment of 2% through a slip casting method. The morphological surface properties of the samples are observed by using Scanning Electron Microscope (SEM). It is shown that the graphite particle is well mixed and homogenously dispersed in biopolymer matrix. Meanwhile, the mechanical response of materials by monitoring the change in the material properties in terms of frequency and temperature of the samples were determined using Dynamic Mechanical Analysis (DMA). The calculated cross-linked density of biopolymer composites revealed the increment of graphite particle loading at 8% gives highest results with 260.012 x 103 M/m3.

  11. On the mechanical properties of selenite glass nanocomposites

    Science.gov (United States)

    Bar, Arun Kr.; Kundu, Ranadip; Roy, Debasish; Bhattacharya, Sanjib

    2016-05-01

    In this paper the room temperature micro-hardness of selenite glass-nanocomposites has been measured using a Vickers and Knoop micro hardness tester where the applied load varies from 0.01N to 0.98 N. A significant indentation size effect was observed for each sample at relatively low indentation test loads. The classical Meyer's law and the proportional specimen resistance model were used to analyze the micro-hardness behavior. It was found that the selenite glass-nanocomposite becomes harder with increasing CuI composition and the work hardening coefficient and mechanical properties like Young modulus, E, were also calculated. Our results open the way for the preparation, application and investigation of significant mechanical properties of new type of glass-nanocomposites.

  12. Conductive magnetorheological elastomer: fatigue dependent impedance-mechanic coupling properties

    Science.gov (United States)

    Wang, Yu; Xuan, Shouhu; Ge, Lin; Wen, Qianqian; Gong, Xinglong

    2017-01-01

    This work investigated the relationship between the impedance properties and dynamic mechanical properties of magnetorheological elastomers (MREs) under fatigue loading. The storage modulus and the impedance properties of MREs were highly influenced by the pressure and magnetic field. Under the same experimental condition, the two characteristics exhibited similar fatigue dependent change trends. When pressure was smaller than 10 N, the capacitance of MRE could be divided into four sections with the increase of the cyclic numbers. The relative equivalent circuit model was established to fit the experimental results of the impedance spectra. Each parameter of circuit element reflected the change of fatigue loading, relative microstructure of MRE, MRE-electrode interface layer, respectively. Based on the above analysis, the real-time and nondestructive impedance method was demonstrated to be high potential on detecting the fatigue of the MRE device.

  13. Mechanical, elastic and thermodynamic properties of crystalline lithium silicides

    CERN Document Server

    Schwalbe, Sebastian; Trepte, Kai; Biedermann, Franziska; Mertens, Florian; Kortus, Jens

    2016-01-01

    We investigate crystalline thermodynamic stable lithium silicides phases (LixSiy) with density functional theory (DFT) and a force-field method based on modified embedded atoms (MEAM) and compare our results with experimental data. This work presents a fast and accurate framework to calculate thermodynamic properties of crystal structures with large unit cells with MEAM based on molecular dynamics (MD). Mechanical properties like the bulk modulus and the elastic constants are evaluated in addition to thermodynamic properties including the phonon density of states, the vibrational free energy and the isochoric/isobaric specific heat capacity for Li, Li12Si7, Li7Si3, Li13Si4, Li15Si4, Li21Si5, Li17Si4, Li22Si5 and Si. For a selected phase (Li13Si4) we study the effect of a temperature dependent phonon density of states and its effect on the isobaric heat capacity.

  14. Mechanical Properties of Nonwoven Reinforced Thermoplastic Polyurethane Composites.

    Science.gov (United States)

    Tausif, Muhammad; Pliakas, Achilles; O'Haire, Tom; Goswami, Parikshit; Russell, Stephen J

    2017-06-05

    Reinforcement of flexible fibre reinforced plastic (FRP) composites with standard textile fibres is a potential low cost solution to less critical loading applications. The mechanical behaviour of FRPs based on mechanically bonded nonwoven preforms composed of either low or high modulus fibres in a thermoplastic polyurethane (TPU) matrix were compared following compression moulding. Nonwoven preform fibre compositions were selected from lyocell, polyethylene terephthalate (PET), polyamide (PA) as well as para-aramid fibres (polyphenylene terephthalamide; PPTA). Reinforcement with standard fibres manifold improved the tensile modulus and strength of the reinforced composites and the relationship between fibre, fabric and composite's mechanical properties was studied. The linear density of fibres and the punch density, a key process variable used to consolidate the nonwoven preform, were varied to study the influence on resulting FRP mechanical properties. In summary, increasing the strength and degree of consolidation of nonwoven preforms did not translate to an increase in the strength of resulting fibre reinforced TPU-composites. The TPU composite strength was mainly dependent upon constituent fibre stress-strain behaviour and fibre segment orientation distribution.

  15. The effects of the size of nanocrystalline materials on their thermodynamic and mechanical properties.

    Science.gov (United States)

    Yu, Xiaohua; Zhan, Zhaolin

    2014-01-01

    This work has considered the intrinsic influence of bond energy on the macroscopic, thermodynamic, and mechanical properties of crystalline materials. A general criterion is proposed to evaluate the properties of nanocrystalline materials. The interrelation between the thermodynamic and mechanical properties of nanomaterials is presented and the relationship between the variation of these properties and the size of the nanomaterials is explained. The results of our work agree well with thermodynamics, molecular dynamics simulations, and experimental results. This method is of significance in investigating the size effects of nanomaterials and provides a new approach for studying their thermodynamic and mechanical properties.

  16. Mechanical Properties of Nanoscopic Lipid Domains.

    Science.gov (United States)

    Nickels, Jonathan D; Cheng, Xiaolin; Mostofian, Barmak; Stanley, Christopher; Lindner, Benjamin; Heberle, Frederick A; Perticaroli, Stefania; Feygenson, Mikhail; Egami, Takeshi; Standaert, Robert F; Smith, Jeremy C; Myles, Dean A A; Ohl, Michael; Katsaras, John

    2015-12-23

    The lipid raft hypothesis presents insights into how the cell membrane organizes proteins and lipids to accomplish its many vital functions. Yet basic questions remain about the physical mechanisms that lead to the formation, stability, and size of lipid rafts. As a result, much interest has been generated in the study of systems that contain similar lateral heterogeneities, or domains. In the current work we present an experimental approach that is capable of isolating the bending moduli of lipid domains. This is accomplished using neutron scattering and its unique sensitivity to the isotopes of hydrogen. Combining contrast matching approaches with inelastic neutron scattering, we isolate the bending modulus of ∼13 nm diameter domains residing in 60 nm unilamellar vesicles, whose lipid composition mimics the mammalian plasma membrane outer leaflet. Importantly, the bending modulus of the nanoscopic domains differs from the modulus of the continuous phase surrounding them. From additional structural measurements and all-atom simulations, we also determine that nanoscopic domains are in-register across the bilayer leaflets. Taken together, these results inform a number of theoretical models of domain/raft formation and highlight the fact that mismatches in bending modulus must be accounted for when explaining the emergence of lateral heterogeneities in lipid systems and biological membranes.

  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. Mechanical Properties of Calcium Fluoride-Based Composite Materials

    Science.gov (United States)

    Kleczewska, Joanna; Pryliński, Mariusz; Podlewska, Magdalena; Sokołowski, Jerzy; Łapińska, Barbara

    2016-01-01

    Aim of the study was to evaluate mechanical properties of light-curing composite materials modified with the addition of calcium fluoride. The study used one experimental light-curing composite material (ECM) and one commercially available flowable light-curing composite material (FA) that were modified with 0.5–5.0 wt% anhydrous calcium fluoride. Morphology of the samples and uniformity of CaF2 distribution were analyzed using Scanning Electron Microscopy (SEM) and Energy Dispersive Spectroscopy (EDS). Mechanical properties were tested after 24-hour storage of specimens in dry or wet conditions. Stored dry ECM enriched with 0.5–1.0 wt% CaF2 showed higher tensile strength values, while water storage of all modified ECM specimens decreased their tensile strength. The highest Vickers hardness tested after dry storage was observed for 2.5 wt% CaF2 content in ECM. The addition of 2.0–5.0 wt% CaF2 to FA caused significant decrease in tensile strength after dry storage and overall tensile strength decrease of modified FA specimens after water storage. The content of 2.0 wt% CaF2 in FA resulted in the highest Vickers hardness tested after wet storage. Commercially available composite material (FA), unmodified with fluoride addition, demonstrated overall significantly higher mechanical properties. PMID:28004001

  19. Mechanical Properties of Calcium Fluoride-Based Composite Materials

    Directory of Open Access Journals (Sweden)

    Monika Łukomska-Szymańska

    2016-01-01

    Full Text Available Aim of the study was to evaluate mechanical properties of light-curing composite materials modified with the addition of calcium fluoride. The study used one experimental light-curing composite material (ECM and one commercially available flowable light-curing composite material (FA that were modified with 0.5–5.0 wt% anhydrous calcium fluoride. Morphology of the samples and uniformity of CaF2 distribution were analyzed using Scanning Electron Microscopy (SEM and Energy Dispersive Spectroscopy (EDS. Mechanical properties were tested after 24-hour storage of specimens in dry or wet conditions. Stored dry ECM enriched with 0.5–1.0 wt% CaF2 showed higher tensile strength values, while water storage of all modified ECM specimens decreased their tensile strength. The highest Vickers hardness tested after dry storage was observed for 2.5 wt% CaF2 content in ECM. The addition of 2.0–5.0 wt% CaF2 to FA caused significant decrease in tensile strength after dry storage and overall tensile strength decrease of modified FA specimens after water storage. The content of 2.0 wt% CaF2 in FA resulted in the highest Vickers hardness tested after wet storage. Commercially available composite material (FA, unmodified with fluoride addition, demonstrated overall significantly higher mechanical properties.

  20. Mechanical Properties of a Primary Cilium Measured by Resonant Oscillation

    Science.gov (United States)

    Resnick, Andrew

    Primary cilia are ubiquitous mammalian cellular substructures implicated in an ever-increasing number of regulatory pathways. The well-established `ciliary hypothesis' states that physical bending of the cilium (for example, due to fluid flow) initiates signaling cascades, yet the mechanical properties of the cilium remain incompletely measured, resulting in confusion regarding the biological significance of flow-induced ciliary mechanotransduction. In this work we measure the mechanical properties of a primary cilium by using an optical trap to induce resonant oscillation of the structure. Our data indicate 1), the primary cilium is not a simple cantilevered beam, 2), the base of the cilium may be modeled as a nonlinear rotatory spring, the linear spring constant `k' of the cilium base calculated to be (4.6 +/- 0.62)*10-12 N/rad and nonlinear spring constant ` α' to be (-1 +/- 0.34) *10-10 N/rad2 , and 3) the ciliary base may be an essential regulator of mechanotransduction signalling. Our method is also particularly suited to measure mechanical properties of nodal cilia, stereocilia, and motile cilia, anatomically similar structures with very different physiological functions.

  1. Composition, structure and mechanical properties of several natural cellular materials

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    The stem piths of sunflower, kaoliang and corn are natural cellular materials. In this paper, the contents of the compositions of these piths are determined and their cell shapes and structures are examined through scanning electron microscope (SEM) and optical microscope. Further research is conducted in the effects of the compositions and structures of the piths on the mechanical properties after testing the partial mechanical properties. The results show that the total cellulose, hemicelluloses and lignin content of each sample approaches 75% of the dry mass of its primary cell walls. With the fall of R value, a parameter relative to the contents of the main compositions, the flexibilities of the cellular piths descend while their stresses and rigidities increase. The basic cell shape making up the sunflower pith is approximately a tetrakaidehedron. The stem piths of kaoliang and corn are made up of cells close to hexangular prisms and a few tubular ones which can observably reinforce their mechanical properties in the axial directions.

  2. Bulk Mechanical Properties of Single Walled Carbon Nanotube Electrodes

    Science.gov (United States)

    Giarra, Matthew; Landi, Brian; Cress, Cory; Raffaelle, Ryne

    2007-03-01

    The unique properties of single walled carbon nanotubes (SWNTs) make them especially well suited for use as electrodes in power devices such as lithium ion batteries, hydrogen fuel cells, solar cells, and supercapacitors. The performances of such devices are expected to be influenced, at least in part, by the mechanical properties of the SWNTs used in composites or in stand alone ``papers.'' Therefore, the elastic moduli and ultimate tensile strengths of SWNT papers were measured as functions of temperature, SWNT purity, SWNT length, and SWNT bundling. The SWNTs used to produce the papers were synthesized in an alexandrite laser vaporization reactor at 1100^oC and purified using conventional acid-reflux conditions. Characterization of the SWNTs was performed using SEM, BET, TGA, and optical and Raman spectroscopy. The purified material was filtered and dried to yield papers of bundled SWNTs which were analyzed using dynamic mechanical analysis (DMA). It was observed that the mechanical properties of acid-refluxed SWNT papers were significantly improved by controlled thermal oxidation and strain-hardening. Elastic moduli of SWNT papers were measured between 3 and 6 GPa. Ultimate (breaking) tensile stresses were measured between 45 and 90 MPa at 1-3% strain. These results and their implications in regard to potential applications in power devices will be discussed.

  3. 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

  4. Structure and mechanical properties of austenitic steel after cold rolling

    Directory of Open Access Journals (Sweden)

    A. Kurc-Lisiecka

    2011-02-01

    Full Text Available Purpose: The aim of the paper is to determine the influence of the cold plastic deformation within the range 18-79% and heat treatment in a temperature range of 500 to 700°C on the microstructure and mechanical properties of austenitic stainless steel grade X5CrNi18-8.Design/methodology/approach: The investigations included observations of the microstructure on a light microscope, researches of mechanical properties in a static tensile test and hardness measurements made by Vickers’s method. The analysis of the phase composition was carried out on the basis of X-ray researches. Whereas, X-ray quantitative phase analysis was carried out by the Averbach Cohen method.Findings: Heat treatment of X5CrNi18-8 stainless steel in the range 500-700°C causes a significant decrease of the mechanical properties (Rm, Rp0.2 and increase of elongation (A. Hardness of investigated steel drops with decrease of cold working degree and increase of heat treatment temperature.Research limitations/implications: The analysis of the obtained results permits to state that the heat treatment causes an essential changes of the microstructure connected with fading of cold deformation. Heating of cold rolled austenitic stainless steels can cause a reverse transformation α’ → γ.Practical implications: Two-phase structure α’+γ of austenitic Cr-Ni steel in deformed state working at elevated temperature undergo a transformation. It significantly influences mechanical properties of steel. Austenite phase undergoes a recrystallization, while martensite α’ phase undergoes reverse transformation.Originality/value: The analytic dependence of the yield point of the investigated steel on the cold working degree in cold rolling process has been confirmed. Revealing this relation is of essential practical importance for the technology of sheetmetal forming of austenitic steel.

  5. Mechanics of advanced materials analysis of properties and performance

    CERN Document Server

    Matveenko, Valery

    2015-01-01

    The last decades have seen a large extension of types of materials employed in various applications. In many cases these materials demonstrate mechanical properties and performance that vary significantly from those of their traditional counterparts. Such uniqueness is sought – or even specially manufactured – to meet increased requirements on modern components and structures related to their specific use. As a result, mechanical behaviors of these materials under different loading and environmental conditions are outside the boundaries of traditional mechanics of materials, presupposing development of new characterization techniques, theoretical descriptions and numerical tools. The book presents interesting examples of recent developments in this area. Among the studied materials are bulk metallic glasses, metamaterials, special composites, piezoelectric smart structures, nonwovens, etc.

  6. Mechanical Properties and Biocompatibility of a Biomaterial Based on Deproteinized Hydroxyapatite and Endodentine Cement

    Directory of Open Access Journals (Sweden)

    Rupeks Lauris

    2016-05-01

    Full Text Available Hydroxyapatite is used for bone reconstruction, in order to improve its mechanical properties different substances can be added. In our study new biomaterial is created from deproteinised hydroxyaptite and endodentic cement, its mechanical properties were tested. Material was implanted subcutaneous in rats, then histological and biocompatability tests were performed. Results indicate that stuff has good mechanical properties, short setting time and gradual resorption creating porosity and ability to integrate in bone.

  7. Determination of Mechanical Properties of Microcapsules

    NARCIS (Netherlands)

    Sagis, L.M.C.

    2015-01-01

    Mechanical characterization methods can be important tools in optimizing the design of an encapsulation system. Food microcapsules can be subjected to considerable shear and extensional forces during their life cycle, and the shell of the capsules needs to be designed with sufficient mechanical stre

  8. STUDIES ON THE MECHANICAL PROPERTIES AND CRYSTALLIZATION BEHAVIOR OF POLYETHYLENE COMPOSITES

    Institute of Scientific and Technical Information of China (English)

    ZHU Jin; OU Yuchun; FENG Yupeng

    1995-01-01

    The effects of interfacial modifier on the mechanical, dynamic mechanical properties and crystallization behavior of the polyethylene composites were investigated in the present paper.It was found that the interfacial modifer significantly improved the mechanical properties,influenced the dynamic mechanical spectra and slightly changed the crystallization behavior.The results showed that the interfacial modifier changed the dispersion state of dispersed phase of the composites, resulting in different phase structure, which was the major reason leading to different mechanical and crystallization properties.

  9. Mechanical and Thermophysical Properties of Cerium Monopnictides

    Science.gov (United States)

    Bhalla, Vyoma; Singh, Devraj; Jain, S. K.

    2016-03-01

    The ultrasonic attenuation due to phonon-phonon interaction, thermoelastic relaxation and dislocation damping mechanisms has been investigated in cerium monopnictides CeX (X: N, P, As, Sb and Bi) for longitudinal and shear waves along {third-order elastic constants of CeX have also been computed in the temperature range 0 K to 500 K using Coulomb and Born-Mayer potential upto second nearest neighbours. The computed values of these elastic constants have been applied to find out Young's moduli, bulk moduli, Breazeale's non-linearity parameters, Zener anisotropy, ultrasonic velocity, ultrasonic Grüneisen parameter, thermal relaxation time, acoustic coupling constants and ultrasonic attenuation. The fracture/toughness ratio is less than 1.75, which shows that the chosen materials are brittle in nature as found for other monopnictides. The drag coefficient acting on the motion of screw and edge dislocations due to shear and compressional phonon viscosities of the lattice have also been evaluated for both the longitudinal and shear waves. The thermoelastic loss and dislocation damping loss are negligible in comparison to loss due to Akhieser damping (phonon-phonon interaction). The obtained results for CeX are in qualitative agreement with other semi-metallic monopnictides.

  10. Length-dependent mechanical properties of gold nanowires.

    Science.gov (United States)

    Han, Jing; Fang, Liang; Sun, Jiapeng; Han, Ying; Sun, Kun

    2012-12-01

    The well-known "size effect" is not only related to the diameter but also to the length of the small volume materials. It is unfortunate that the length effect on the mechanical behavior of nanowires is rarely explored in contrast to the intensive studies of the diameter effect. The present paper pays attention to the length-dependent mechanical properties of 〈111〉-oriented single crystal gold nanowires employing the large-scale molecular dynamics simulation. It is discovered that the ultrashort Au nanowires exhibit a new deformation and failure regime-high elongation and high strength. The constrained dislocation nucleation and transient dislocation slipping are observed as the dominant mechanism for such unique combination of high strength and high elongation. A mechanical model based on image force theory is developed to provide an insight to dislocation nucleation and capture the yield strength and nucleation site of first partial dislocation indicated by simulation results. Increasing the length of the nanowires, the ductile-to-brittle transition is confirmed. And the new explanation is suggested in the predict model of this transition. Inspired by the superior properties, a new approach to strengthen and toughen nanowires-hard/soft/hard sandwich structured nanowires is suggested. A preliminary evidence from the molecular dynamics simulation corroborates the present opinion.

  11. Mechanical properties of thermoplastic composites reinforced with Entada Mannii fibre

    Directory of Open Access Journals (Sweden)

    Oluwayomi BALOGUN

    2017-06-01

    Full Text Available The mechanical properties and fracture mechanisms of thermoplastic composites reinforced with Entada mannii fibres was investigated. Polypropylene reinforced with 1, 3, 5, and 7 wt% KOH treated and untreated Entada mannii fibres were processed using a compression moulding machine. The tensile properties, impact strength, and flexural properties of the composites were evaluated while the tensile fracture surface morphology was examined using scanning electron microscopy. The results show that reinforcing polypropylene with Entada mannii fibres resulted in improvement of the tensile strength and elastic modulus. This improvement is remarkable for 5 wt% KOH treated Entada mannii fibre reinforced composites by 28 % increase as compared with the unreinforced polypropylene. The composites reinforced with Entada mannii fibres also had impact strength values of 70 % higher than the unreinforced polypropylene. However, the polypropylene reinforced with 5 and 7wt% KOH treated fibres exhibited significantly higher flexural strength and Young’s modulus by 53% and 52% increase as compared with the unreinforced polypropylene. The fracture surface of the polypropylene composites reinforced with untreated Entada mannii fibres were characterized by fibre debonding, fibre pull-out and matrix yielding while less voids and fibre pull-outs are observed in the composites reinforced with KOH treated Entada mannii fibres. v

  12. Improvement of mechanical properties of steel sheet

    Institute of Scientific and Technical Information of China (English)

    Bashchenko; A.; P.; Knokhin; V.; G.; Beliavsky; P.; B.; Traino; A.; I.

    2005-01-01

    Consideration was given to some peculiarities of the resource-saving IDT-production that implements metallophysical principles of hot deformation effect upon the formation of martensite and perlite structures of alloy steels as well as upon their functional properties by way of DTT-cycling.

  13. Size dependency and potential field influence on deriving mechanical properties of carbon nanotubes using molecular dynamics

    Directory of Open Access Journals (Sweden)

    K.G.S. Dilrukshi

    2015-07-01

    Full Text Available A thorough understanding on the mechanical properties of carbon nanotube (CNT is essential in extending the advanced applications of CNT based systems. However, conducting experiments to estimate mechanical properties at this scale is extremely challenging. Therefore, development of mechanistic models to estimate the mechanical properties of CNTs along with the integration of existing continuum mechanics concepts is critically important. This paper presents a comprehensive molecular dynamics simulation study on the size dependency and potential function influence of mechanical properties of CNT. Commonly used reactive bond order (REBO and adaptive intermolecular reactive bond order (AIREBO potential functions were considered in this regard. Young’s modulus and shear modulus of CNTs are derived by integrating classical continuum mechanics concepts with molecular dynamics simulations. The results indicate that the potential function has a significant influence on the estimated mechanical properties of CNTs, and the influence of potential field is much higher when studying the torsional behaviour of CNTs than the tensile behaviour.

  14. Mechanical properties of short carbon/glass fiber reinforced high mechanical performance epoxy resins

    Institute of Scientific and Technical Information of China (English)

    张竞; 黄培

    2009-01-01

    To research the relationship between epoxy and fiber inherent property and mechanical properties of composite,we prepared a series of composites using three kinds of high mechanical performance epoxy resins as matrices and reinforced by the same volume fraction(5%)of short carbon and glass fiber.Their mechanical properties were investigated from the perspective of chemical structure and volume shrinkage ratio of epoxy.We analyzed their tensile strength and modulus based on the mixing rule and Halpin-Tsai eq...

  15. Compressive and tensile mechanical properties of the porcine nasal septum.

    Science.gov (United States)

    Al Dayeh, Ayman A; Herring, Susan W

    2014-01-03

    The expanding nasal septal cartilage is believed to create a force that powers midfacial growth. In addition, the nasal septum is postulated to act as a mechanical strut that prevents the structural collapse of the face under masticatory loads. Both roles imply that the septum is subject to complex biomechanical loads during growth and mastication. The purpose of this study was to measure the mechanical properties of the nasal septum to determine (1) whether the cartilage is mechanically capable of playing an active role in midfacial growth and in maintaining facial structural integrity and (2) if regional variation in mechanical properties is present that could support any of the postulated loading regimens. Porcine septal samples were loaded along the horizontal or vertical axes in compression and tension, using different loading rates that approximate the in vivo situation. Samples were loaded in random order to predefined strain points (2-10%) and strain was held for 30 or 120 seconds while relaxation stress was measured. Subsequently, samples were loaded until failure. Stiffness, relaxation stress and ultimate stress and strain were recorded. Results showed that the septum was stiffer, stronger and displayed a greater drop in relaxation stress in compression compared to tension. Under compression, the septum displayed non-linear behavior with greater stiffness and stress relaxation under faster loading rates and higher strain levels. Under tension, stiffness was not affected by strain level. Although regional variation was present, it did not strongly support any of the suggested loading patterns. Overall, results suggest that the septum might be mechanically capable of playing an active role in midfacial growth as evidenced by increased compressive residual stress with decreased loading rates. However, the low stiffness of the septum compared to surrounding bone does not support a strut role. The relatively low stiffness combined with high stress relaxation

  16. Evaluation of the transformation mechanisms and mechanical properties of ferrite: martensite microalloyed steels

    Directory of Open Access Journals (Sweden)

    Ovri Henry

    2008-03-01

    Full Text Available The influence of starting point microstructures on the transformation mechanisms and mechanical properties of a micro alloyed steel after annealing in the alpha + gamma region have been investigated. Three different microstructures: austenite, pearlite in a ferrite matrix and martensite were used as starting point microstructures for the production of dual (alpha + phase structures in the test steel. Photomicrographs obtained from metallographic examination of the heat treated samples were used as criteria for the assessment of results obtained from impact toughness and hardness testing. The results obtained showed that the transformation mechanisms and hence the morphology of ferrite - martensite microalloyed steels are strongly influenced by their initial microstructural details. Ferrite - martensite structures produced via the intercritical quench (IQ treatment, with martensite as the starting point microstructure, have the best combination of hardness and impact energy.

  17. Porosity and mechanical properties of porous titanium fabricated by gelcasting

    Institute of Scientific and Technical Information of China (English)

    LI Yan; GUO Zhimeng; HAO Junjie; REN Shubin

    2008-01-01

    Porous Ti compacts with large size and complex shape for biomedical applications were fabricated in the porosity range from 40.5% to 53.8% by controlling gelcasting parameters and sintering conditions. The experimental results show that the total porosity and open porosity of porous titanium compacts gelcast from the Ti slurry with 34 vol.% solid loading and sintered at 1100℃ for 1.5h are 46.5% and 40.7%, respectively, and the mechanical properties are as follows: compressive strength 158.6MPa and Young's modulus 8.5GPa, which are similar to those of human cortical bone and appropriate for implanting purpose.

  18. Mechanical properties of timber from wind damaged Norway spruce

    DEFF Research Database (Denmark)

    Hoffmeyer, Preben

    2003-01-01

    . 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...... taken to bending failure and the relations between compression damage and bending strength and stiffness were established. The results showed that significant reductions of bending strength of dry timber are only caused by such wind induced compression damages that are easily recognised at a planed...

  19. Mechanical and electrical properties of polycarbonate nanotube buckypaper composite sheets

    Energy Technology Data Exchange (ETDEWEB)

    Pham, Giang T; Park, Young-Bin; Wang Shiren; Liang Zhiyong; Wang Ben; Zhang, Chuck [High-Performance Materials Institute (HPMI), Department of Industrial and Manufacturing Engineering, Florida A and M University, Florida State University College of Engineering, 2525 Pottsdamer Street, Tallahassee, FL 32310-6046 (United States); Funchess, Percy; Kramer, Leslie [Lockheed Martin Missiles and Fire Control-Orlando, Orlando, FL 32819-8907 (United States)], E-mail: gte640q@yahoo.com

    2008-08-13

    The thermogravimetric, mechanical, and electrical properties of composite sheets produced by infiltrating single-wall carbon nanotube films (also known as 'buckypapers') with polycarbonate solution were characterized. The composite sheets showed improved stiffness and toughness, while the electrical conductivity decreased, as compared to a neat buckypaper. In addition, polycarbonate/buckypaper composite sheets showed higher resistance to handling and processing damages. Experimental results suggest the viability of the infiltration process as a means to toughen buckypapers and to fabricate polymer/carbon nanotube composites having high nanotube concentration and controlled nanotube structure.

  20. Mechanical and structural properties of sputtered Ni/Ti multilayers

    Energy Technology Data Exchange (ETDEWEB)

    Senthil Kumar, M.; Boeni, P.; Tixier, S.; Clemens, D.; Horisberger, M. [Paul Scherrer Inst. (PSI), Villigen (Switzerland)

    1997-09-01

    Ni/Ti bilayers have been prepared by dc-magnetron sputtering in order to study their mechanical and structural properties. A remarkable reduction of stress is observed when the Ni layers are sputtered reactively in argon with a high partial pressure of air. The high angle x-ray diffraction studies show a tendency towards amorphisation of the Ni layers with increasing air flow. The low angle measurements indicate a substantial reduction of interdiffusion resulting in smoother interfaces with increasing air content. (author) 2 figs., 2 refs.

  1. MICROSTRUCTURE AND MECHANICAL PROPERTIES OF NOVEL 718 SUPERALLOY

    Institute of Scientific and Technical Information of China (English)

    J.H. Du; X.D. Lü; J.L. Qu; Q. Deng; J.Y. Zhuang; Z.Y. Zhong

    2006-01-01

    Recently, a novel 718 superalloy with remarkable structural stability at 680℃ has been designed and fabricated by CISRI (Central Iron and Steel Research Institute) etc. Phase identification of novel 718 alloy under the above-mentioned heat-treatment condition was performed using optical microscopy (OM), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). Results show that the novel 718 alloy has outstanding structural stability at 680℃. The novel 718alloy possess excellent structural stability and good mechanical properties, which is attributed to y-phase strengthening and also to the specific sandwich structure of the γ′ + γ" strengthening phase.

  2. Electronic, mechanical and dielectric properties of silicane under tensile strain

    Energy Technology Data Exchange (ETDEWEB)

    Jamdagni, Pooja, E-mail: j.poojaa1228@gmail.com; Sharma, Munish; Ahluwalia, P. K. [Physics Department, Himachal Pradesh University, Shimla, Himachal Pradesh, India 171005 (India); Kumar, Ashok [Physics Department, Panjab University, Chandigarh, India, 160014 (India); Thakur, Anil [Physics Department, Govt. Collage Solan, Himachal Pradesh, India,173212 (India)

    2015-05-15

    The electronic, mechanical and dielectric properties of fully hydrogenated silicene i.e. silicane in stable configuration are studied by means of density functional theory based calculations. The band gap of silicane monolayer can be flexibly reduced to zero when subjected to bi-axial tensile strain, leading to semi-conducting to metallic transition, whereas the static dielectric constant for in-plane polarization increases monotonically with increasing strain. Also the EEL function show the red shift in resonance peak with tensile strain. Our results offer useful insight for the application of silicane monolayer in nano-optical and electronics devices.

  3. Physical and Mechanical Properties of Sorghum Grains (Sorghum Vulgare)

    OpenAIRE

    2016-01-01

    The physical and mechanical properties of sorghum grains (sorghum vulgare) were studied at varying moisture contents of 13%, 20% and 30% (w.b). The four varieties of sorghum grains studied include; Dura, Guinea, Faterita and Kafir. Results indicate that the size ranges were 3.94mm - 4.83mm for Dura variety; 3.75mm - 4.54mm for Guinea variety; 3.21mm - 4.42mm for Kafir variety and 2.70mm - 4.14mm for Faterita variety. Irregularities in the shapes of the grains were observed but all approximate...

  4. Mechanical Properties of Oil Palm Empty Fruit Bunch Fiber

    Science.gov (United States)

    Gunawan, Fergyanto E.; Homma, Hiroomi; Brodjonegoro, Satryo S.; Hudin, Afzer Bin Baseri; Zainuddin, Aryanti Binti

    In tropical countries such as Indonesia and Malaysia, the empty fruit bunches are wastes of the oil palm industry. The wastes are abundantly available and has reached a level that severely threats the environment. Therefore, it is a great need to find useful applications of those waste materials; but firstly, the mechanical properties of the EFB fiber should be quantified. In this work, a small tensile test machine is manufactured, and the tensile test is performed on the EFB fibers. The results show that the strength of the EFB fiber is strongly affected by the fiber diameter; however, the fiber strength is relatively low in comparison to other natural fibers.

  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...... taken to bending failure and the relations between compression damage and bending strength and stiffness were established. The results showed that significant reductions of bending strength of dry timber are only caused by such wind induced compression damages that are easily recognised at a planed...

  6. Influence of Compatibilizer and Processing Conditions on Morphology, Mechanical Properties, and Deformation Mechanism of PP/Clay Nanocomposite

    Directory of Open Access Journals (Sweden)

    B. Akbari

    2012-01-01

    Full Text Available Polypropylene/montmorillonite nanocomposite was prepared by melt intercalation method using a twin-screw extruder with starve feeding system in this paper. The effects of compatibilizer, extruder rotor speed and feeding rate on properties of nanocomposite were investigated. Structure, tensile, and impact properties and deformation mechanism of the compounds were studied. For investigation of structure and deformation mechanisms, X-ray diffraction (XRD and transmission optical microscopy (TOM techniques were utilized, respectively. The results illustrate that introduction of the compatibilizer and also variation of the processing conditions affect structure and mechanical properties of nanocomposite.

  7. 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

  8. 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

  9. The thermal and mechanical properties of electron beam-irradiated polylactide

    Energy Technology Data Exchange (ETDEWEB)

    Kuk, In Seol; Jung, Chan Hee; Hwang, In Tae; Choi, Jae Hak; Nho, Young Chang [Korea Atomic Energy Research Institute, Jeongeup (Korea, Republic of)

    2010-06-15

    The effect of electron beam irradiation on the thermal and mechanical properties of polylactide (PLA) was investigated in this research. PLA films were irradiated by electron beams at different absorption doses ranging from 20 to 200 kGy. The thermal and mechanical properties of the irradiated PLA films were investigated by means of differential scanning calorimeter, thermogravimetric analyzer, universal testing machine, dynamic mechanical analyzer, and thermal mechanical analyzer. The results revealed that the chain scission of the PLA predominated over the crosslinking during the irradiation, which considerably deteriorated the thermal and mechanical properties of the PLA.

  10. Mechanical properties of the porcine bile duct wall

    Directory of Open Access Journals (Sweden)

    Andersen Helle

    2004-07-01

    Full Text Available Abstract Background and Aim The function of the common bile duct is to transport bile from the liver and the gall bladder to the duodenum. Since the bile duct is a distensible tube consisting mainly of connective tissue, it is important to obtain data on the passive mechanical wall properties. The aims of this study were to study morphometric and biomechanical wall properties during distension of the bile duct. Methods Ten normal porcine common bile ducts were examined in vitro. A computer-controlled volume ramp infusion system with concomitant pressure recordings was constructed. A video camera provided simultaneous measurement of outer dimensions of the common bile duct. Wall stresses and strains were computed. Results The common bile duct length increased by 25% from 24.4 ± 1.8 mm at zero pressure to 30.5 ± 2.0 mm at 5 kPa (p (βε - 1. The circumferential stress-strain curve was shifted to the left when compared to the longitudinal stress-strain curve, i.e. the linear constants (α values were different (p 0.5. Conclusion The porcine bile duct exhibited nonlinear anisotropic mechanical properties.

  11. Mechanical Properties of Four Human Longbones.

    Science.gov (United States)

    1981-11-30

    Ultimate Properties of Compact Bone Tissue," J. Biomechanics, 1975, pp. 393-405. 41. Bass, William M., Human Osteology: A Laboratory and Field Manual of...bone’s proximal and distal epiphyses. Most of the measurements used can be found in the antropological literature [1, 2, 4, 5, 61. Those that cannot...using strain sensing load cells connected to j a manual switch and balance unit and digital display. The torque applied was inferred by the tensile

  12. Ferrosilt (Red Mud): Geotechnical Properties and Soil Mechanical Considerations

    Science.gov (United States)

    Jenny, F. C.

    The disposal of ferrosilt tailings creates problems because of the rather unusual geotechnical properties. Ferrosilt samples from three different bauxites were tested in connection with the alumina plant project in Wilhelmshaven (West Germany). The results of these laboratory tests explain various ferrosilt slides experienced during the past. Should ferrosilt be utilized for application where better physical qualities of the material are required it is possible to separate the coarser fraction from the finer fractions by using cyclons. The soil mechanical properties of the coarser fraction — called ferrosilt-sand — is of much better quality than the ferrosilt proper. On the other hand the quality of the finder fractions is not much inferior to the ferrosilt.

  13. Estimation of mechanical properties of nanomaterials using artificial intelligence methods

    Science.gov (United States)

    Vijayaraghavan, V.; Garg, A.; Wong, C. H.; Tai, K.

    2014-09-01

    Computational modeling tools such as molecular dynamics (MD), ab initio, finite element modeling or continuum mechanics models have been extensively applied to study the properties of carbon nanotubes (CNTs) based on given input variables such as temperature, geometry and defects. Artificial intelligence techniques can be used to further complement the application of numerical methods in characterizing the properties of CNTs. In this paper, we have introduced the application of multi-gene genetic programming (MGGP) and support vector regression to formulate the mathematical relationship between the compressive strength of CNTs and input variables such as temperature and diameter. The predictions of compressive strength of CNTs made by these models are compared to those generated using MD simulations. The results indicate that MGGP method can be deployed as a powerful method for predicting the compressive strength of the carbon nanotubes.

  14. Bioprinting of hybrid tissue constructs with tailorable mechanical properties

    Energy Technology Data Exchange (ETDEWEB)

    Schuurman, W; Khristov, V; Pot, M W; Dhert, W J A; Malda, J [Department of Orthopaedics, University Medical Center Utrecht (Netherlands); Van Weeren, P R, E-mail: j.malda@umcutrecht.nl [Faculty of Veterinary Sciences, Department of Equine Sciences, Utrecht University (Netherlands)

    2011-06-15

    Tissue/organ printing aims to recapitulate the intrinsic complexity of native tissues. For a number of tissues, in particular those of musculoskeletal origin, adequate mechanical characteristics are an important prerequisite for their initial handling and stability, as well as long-lasting functioning. Hence, organized implants, possessing mechanical characteristics similar to the native tissue, may result in improved clinical outcomes of regenerative approaches. Using a bioprinter, grafts were constructed by alternate deposition of thermoplastic fibers and (cell-laden) hydrogels. Constructs of different shapes and sizes were manufactured and mechanical properties, as well as cell viability, were assessed. This approach yields novel organized viable hybrid constructs, which possess favorable mechanical characteristics, within the same range as those of native tissues. Moreover, the approach allows the use of multiple hydrogels and can thus produce constructs containing multiple cell types or bioactive factors. Furthermore, since the hydrogel is supported by the thermoplastic material, a broader range of hydrogel types can be used compared to bioprinting of hydrogels alone. In conclusion, we present an innovative and versatile approach for bioprinting, yielding constructs of which the mechanical stiffness provided by thermoplastic polymers can potentially be tailored, and combined specific cell placement patterns of multiple cell types embedded in a wide range of hydrogels. (communication)

  15. VERIFICATION OF TORSIONAL OSCILLATING MECHANICAL SYSTEM DYNAMIC CALCULATION RESULTS

    OpenAIRE

    2014-01-01

    On our department we deal with optimization and tuning of torsional oscillating mechanical systems. When solving these problems we often use results of dynamic calculation. The goal of this article is to compare values obtained by computation and experimentally. For this purpose, a mechanical system built in our laboratory was used. At first, classical HARDY type flexible coupling has been applied into the system, then we used a pneumatic flexible shaft coupling developed by us...

  16. Microstructural and Mechanical Properties of Alkali Activated Colombian Raw Materials

    Directory of Open Access Journals (Sweden)

    Maria Criado

    2016-03-01

    Full Text Available Microstructural and mechanical properties of alkali activated binders based on blends of Colombian granulated blast furnace slag (GBFS and fly ash (FA were investigated. The synthesis of alkali activated binders was conducted at 85 °C for 24 h with different slag/fly ash ratios (100:0, 80:20, 60:40, 40:60, 20:80, and 0:100. Mineralogical and microstructural characterization was carried out by means of X-ray diffraction (XRD, Fourier transform infrared spectroscopy (FTIR, Scanning electron microscopy with energy dispersive X-ray spectroscopy (SEM/EDX and Nuclear magnetic resonance (NMR. Mechanical properties were evaluated through the compressive strength, modulus of elasticity and Poisson’s ratio. The results show that two different reaction products were detected in the slag/fly ash mixtures, a calcium silicate hydrate with Al in its structure (C-A-S-H gel and a sodium aluminosilicate hydrate (N-A-S-H gel with higher number of polymerized species and low content in Ca. It was found that with the increase of the amount of added slag, the amount of C-A-S-H gel increased and the amount of N-A-S-H gel decreased. The matrix was more dense and compact with almost absence of pores. The predominance of slag affected positively the compressive strength, Young’s modulus and Poisson’s ratio, with 80% slag and 20% fly ash concrete being the best mechanical performance blend.

  17. Study on Thermal and Mechanical Properties of EPDM Insulation

    Science.gov (United States)

    Zhang, Zhong-Shui; Xu, Jin-Sheng; Chen, Xiong; Jiang, Jing

    As the most common insulation material of solid rocket motors, thermal and mechanical properties of ethylene propylene diene monomer (EPDM) composite are inspected in the study. Referring to the results of thermogravimetric analysis (TGA), composition and morphology of EPDM composite in different thermal degradation degree are investigated by scanning electron microscope (SEM) to inspect the mechanism of thermal insulation. Mechanical properties of EPDM composite in the state of pyrolysis are investigated by uniaxial tensile tests. At the state of initial pyrolysis, composite belongs to the category of hyperelastic-viscoelastic material. The tendency of tensile strength increased and elongation decreased with increasing of heating temperature. Composite behaves as the linear rule at the state of late pyrolysis, which belongs to the category of bittle. The elasticity modulus of curves are almost the same while the heating temperature ranges from 200°C to 300°C, and then gradually go down. The tensile strength of pyrolytic material reach the highest at the heating temperature of 300°C, and the virgin material has the largest elongation.

  18. Dynamic viscoelastic properties of collagen gels with high mechanical strength.

    Science.gov (United States)

    Mori, Hideki; Shimizu, Kousuke; Hara, Masayuki

    2013-08-01

    We developed a new method for the preparation of mechanically strong collagen gels by combining successively basic gel formation, followed by 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide (EDC) cross-linking and lyophilization. Gels cross-linked three times with this method showed stronger mechanical properties (G': 3730±2060 Pa, G″: 288±35 Pa) than a conventional gel that was sequentially cross-linked with EDC once (G': 226±70 Pa, G″: 21±4.4 Pa), but not as strong as the same gel with heating for 30 min at 80°C (G': 7010±830 Pa, G″: 288±35 Pa) reported in our previous paper. The conventional collagen gel was cross-linked with EDC once, heated once, and then subjected twice to a lyophilization-gel formation-cross-linking cycle to give three-cycled gel 2. This gel had the strongest mechanical properties (G': 40,200±18,000 Pa, G″: 3090±1400 Pa, Young's modulus: 0.197±0.069 MPa) of the gels tested. These promising results suggest possible applications of the gels as scaffolds in tissue engineering research.

  19. Mechanical properties of metallic nanowires using tight-binding model

    Science.gov (United States)

    Aish, Mohammed; Starostenkov, Mikhail

    2016-01-01

    The mechanical properties of Nickel nanowires have been studied at different temperatures using molecular dynamics simulations. Molecular Dynamics (MD) simulations have been carried out on pure Nickel (Ni) crystal with face-centered cubic (FCC) lattice upon application of uniaxial tension at nanolevel with a speed of 20 m/s. The deformation corresponds to the direction . To the calculated block of crystal, free boundary conditions are applied in the directions , . A many body interatomic potential for Ni within the second moment approximation of the tight binding model (the Cleri-Rosato potentials) was employed to carry out three dimensional molecular dynamics simulations. MD simulation used to investigate the effect of temperature of Ni nanowire on the nature of deformation and fracture. Temperature effect on the extension property of metal nanowire is discussed in detail. The mechanical strengths and the mechanical strain of the nanowires decrease linearly with the increasing temperature. The feature of deformation energy can be divided into four regions: quasi-elastic, plastic, flow and failure. Experiments have shown that when the temperature increases the yielding stress decreases, the first stage of deformation was narrowed, and the second stage was widened. The results showed that breaking position depended on temperature.

  20. Mechanical properties for irradiated face-centred cubic nanocrystalline metals

    Science.gov (United States)

    Xiao, X. Z.; Song, D. K.; Chu, H. J.; Xue, J. M.; Duan, H. L.

    2015-01-01

    In this paper, a self-consistent plasticity theory is proposed to model the mechanical behaviours of irradiated face-centred cubic nanocrystalline metals. At the grain level, a tensorial crystal model with both irradiation and grain size effects is applied for the grain interior (GI), whereas both grain boundary (GB) sliding with irradiation effect and GB diffusion are considered in modelling the behaviours of GBs. The elastic-viscoplastic self-consistent method with considering grain size distribution is developed to transit the microscopic behaviour of individual grains to the macroscopic properties of nanocrystals (NCs). The proposed theory is applied to model the mechanical properties of irradiated NC copper, and the feasibility and efficiency have been validated by comparing with experimental data. Numerical results show that: (i) irradiation-induced defects can lead to irradiation hardening in the GIs, but the hardening effect decreases with the grain size due to the increasing absorption of defects by GBs. Meanwhile, the absorbed defects would make the GBs softer than the unirradiated case. (ii) There exists a critical grain size for irradiated NC metals, which separates the grain size into the irradiation hardening dominant region (above the critical size) and irradiation softening dominant region (below the critical size). (iii) The distribution of grain size has a significant influence on the mechanical behaviours of both irradiated and unirradiated NCs. The proposed model can offer a valid theoretical foundation to study the irradiation effect on NC materials. PMID:27547091

  1. Study on the Mechanical Properties of Carbon Nanotube/Polyacrylonitrile Composite Fibers

    Institute of Scientific and Technical Information of China (English)

    李建梅; 王彪; 张玉梅; 王华平; 杨崇倡

    2003-01-01

    The method of preparing the multi-walled carbon nanotubes(MWNTs)-polyacrylonitrile (PAN) composite fibers is described and the effects of draw ratio on the mechanical properties of CNT/PAN fibers have also been discussed.The results show that the degrees of MWNTs dispersion in the polymer matrix have much effect on the mechanical properties.

  2. Mechanical Properties and Corrosion Behavior of Low Carbon Steel Weldments

    Directory of Open Access Journals (Sweden)

    Mohamed Mahdy

    2013-01-01

    Full Text Available This research involves studying the mechanical properties and corrosion behavior of “low carbon steel” (0.077wt% C before and after welding using Arc, MIG and TIG welding. The mechanical properties include testing of microhardness, tensile strength, the results indicate that microhardness of TIG, MIG welding is more than arc welding, while tensile strength in arc welding more than TIG and MIG.The corrosion behavior of low carbon weldments was performed by potentiostat at scan rate 3mV.sec-1 in 3.5% NaCl to show the polarization resistance and calculate the corrosion rate from data of linear polarization by “Tafel extrapolation method”. The results indicate that the TIG welding increase the corrosion current density and anodic Tafel slop, while decrease the polarization resistance compared with unwelded low carbon steel. Cyclic polarization were measured to show resistance of specimens to pitting corrosion and to calculate the forward and reveres potentials. The results show shifting the forward, reverse and pitting potentials toward active direction for weldments samples compared with unwelded sample.

  3. Mechanical and microwave absorbing properties of carbon-filled polyurethane.

    Science.gov (United States)

    Kucerová, Z; Zajícková, L; Bursíková, V; Kudrle, V; Eliás, M; Jasek, O; Synek, P; Matejková, J; Bursík, J

    2009-01-01

    Polyurethane (PU) matrix composites were prepared with various carbon fillers at different filler contents in order to investigate their structure, mechanical and microwave absorbing properties. As fillers, flat carbon microparticles, carbon microfibers and multiwalled carbon nanotubes (MWNT) were used. The microstructure of the composite was examined by scanning electron microscopy and transmission electron microscopy. Mechanical properties, namely universal hardness, plastic hardness, elastic modulus and creep were assessed by means of depth sensing indentation test. Mechanical properties of PU composite filled with different fillers were investigated and the composite always exhibited higher hardness, elastic modulus and creep resistance than un-filled PU. Influence of filler shape, content and dispersion was also investigated.

  4. Grain size dependent mechanical properties in nanophase materials

    Energy Technology Data Exchange (ETDEWEB)

    Siegel, R.W. [Argonne National Lab., IL (United States); Fougere, G.E. [Northwestern Univ., Evanston, IL (United States). Dept. of Materials Science and Engineering

    1995-02-01

    It has become possible in recent years to synthesize metals and ceramics under well controlled conditions with constituent grain structures on a manometer size scale (below 100 nm). These new materials have mechanical properties that are strongly grain-size dependent and often significantly different than those of their coarser grained counterparts. Nanophase metals tend to become stronger and ceramics are more easily deformed as grain size is reduced. The observed mechanical property changes appear to be related primarily to grain size limitations and the large percentage of atoms in grain boundary environments. A brief overview of our present knowledge about the grain-size dependent mechanical properties of nanophase materials is presented.

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

    DEFF Research Database (Denmark)

    Smedskjær, Morten Mattrup; Bauchy, Mathieu

    -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.......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...

  6. Elastic properties and mechanical tension of graphene

    Science.gov (United States)

    Ramírez, R.; Herrero, C. P.

    2017-01-01

    Room-temperature simulations of graphene have been performed as a function of the mechanical tension of the layer. Finite-size effects are accurately reproduced by an acoustic dispersion law for the out-of-plane vibrations that, in the long-wave limit, behaves as ρ ω2=σ k2+κ k4 . The fluctuation tension σ is finite (˜0.1 N/m) even when the external mechanical tension vanishes. Transverse vibrations imply a duplicity in the definition of the elastic constants of the layer, as observables related to the real area of the surface may differ from those related to the in-plane projected area. This duplicity explains the variability of experimental data on the Young modulus of graphene based on electron spectroscopy, interferometric profilometry, and indentation experiments.

  7. Dynamic thermo-mechanical properties of various flowable resin composites

    Science.gov (United States)

    Balthazard, Rémy; Vincent, Marin; Dahoun, Abdessellam; Mortier, Eric

    2016-01-01

    Background This study compared the storage modulus (E’), the loss modulus (E’’) and the loss tangent (tan δ) of various flowable resin composites. Material and Methods Grandio Flow (GRF), GrandioSo Heavy Flow (GHF), Filtek Supreme XTE (XTE) and Filtek Bulk Fill (BUL) flowable resins and Clinpro Sealant (CLI) ultra-flowable pit and fissure sealant resin were used. 25 samples were tested using a dynamical mechanical thermal analysis system in bending mode. Measurements were taken within a temperature range of 10 to 55°C. The results were statistically analyzed using mixed-effect and repeated-measure analysis of variance followed by paired multiple comparisons. Results For all the materials, the E’ values decrease with temperature, whereas the tan δ values increase. Irrespective of the temperature, GHF and GRF present E’ and E’’ values significantly higher than all the other materials and CLI presents values significantly lower than all the other materials. Observation of the values for all the materials reveals a linear progression of the tan δ values with temperature. Conclusions A variation in temperature within a physiological range generates modifications in mechanical properties without damaging the material, however. Filler content in volume terms appears to be the crucial parameter in the mechanical behavior of tested materials. Key words:Dynamic mechanical thermal analysis, elastic modulus, filler content, flowable resin composites, loss modulus, loss tangent. PMID:27957266

  8. Mechanical Properties of Heavy Duty Epoxy Coatings

    OpenAIRE

    Reinoso Rodríguez, Rosa

    2013-01-01

    In a first stage, the composition of epoxy coatings is discussed with special focus on the mechanism of curing and the chemistry of curing agents and their advantages and downturns in prospect to their use in the manufacture of epoxy resins. Then literature on the causes of increased brittleness, cracking and degradation of epoxy resins was studied, especially in relation to evolution of the resins in the glassy state, hydrothermal aging and also in relation to chemical aging. ...

  9. Injectability and mechanical properties of magnesium phosphate cements.

    Science.gov (United States)

    Moseke, Claus; Saratsis, Vasileios; Gbureck, Uwe

    2011-12-01

    Up to now magnesium phosphate cements are mainly being utilized in wastewater treatment due to their adsorptive properties. Recently they also have been shown to have a high potential as degradable biocements for application as replacement materials for bone defects. In comparison to degradable calcium phosphate cements they have the advantage of setting at neutral pH, which is favorable in biological environment. In this study two parameters of the cement composition, namely powder-to-liquid ratio (PLR) and citrate content, were varied in order to optimize the injectability properties of the cement paste and the mechanical properties of the reaction product. These properties were determined by means of testing setting time and temperature, paste viscosity, and injectability as well as phase composition and compressive strength of the set cements. Best results were obtained, when the cements were prepared with a PLR of 2.5 and a binder liquid consisting of an aqueous solution of 3 mol/l diammonium hydrogen phosphate and 0.5 mol/l diammonium citrate.

  10. Glass Fiber Reinforced Polypropylene Mechanical Properties Enhancement by Adhesion Improvement

    Directory of Open Access Journals (Sweden)

    Mariana Etcheverry

    2012-06-01

    Full Text Available Glass fibers (GF are the reinforcement agent most used in polypropylene (PP based composites, as they have good balance between properties and costs. However, their final properties are mainly determined by the strength and stability of the polymer-fiber interphase. Fibers do not act as an effective reinforcing material when the adhesion is weak. Also, the adhesion between phases can be easily degraded in aggressive environmental conditions such as high temperatures and/or elevated moisture, and by the stress fields to which the material may be exposed. Many efforts have been done to improve polymer-glass fiber adhesion by compatibility enhancement. The most used techniques include modifications in glass surface, polymer matrix and/or both. However, the results obtained do not show a good costs/properties improvement relationship. The aim of this work is to perform an accurate analysis regarding methods for GF/PP adhesion improvement and to propose a new route based on PP in-situ polymerization onto fibers. This route involves the modification of fibers with an aluminum alkyl and hydroxy-α-olefin and from there to enable the growth of the PP chains using direct metallocenic copolymerization. The adhesion improvements were further proved by fragmentation test, as well as by mechanical properties measurements. The strength and toughness increases three times and the interfacial strength duplicates in PP/GF composites prepared with in-situ polymerized fibers.

  11. Mechanical Properties of non-accreting Neutron Star Crusts

    CERN Document Server

    Hoffman, Kelsey

    2012-01-01

    The mechanical properties of a neutron star crust, such as breaking strain and shear modulus, have implications for the detection of gravitational waves from a neutron star as well as bursts from Soft Gamma-ray Repeaters (SGRs). These properties are calculated here for three different crustal compositions for a non-accreting neutron star that results from three different cooling histories, as well as for a pure iron crust. A simple shear is simulated using molecular dynamics to the crustal compositions by deforming the simulation box. The breaking strain and shear modulus are found to be similar in the four cases, with a breaking strain of ~0.1 and a shear modulus of ~10^{30} dyne cm^{-2} at a density of \\rho = 10^{14} g cm^{-3} for simulations with an initially perfect BCC lattice. With these crustal properties and the observed properties of {PSR J2124-3358} the predicted strain amplitude of gravitational waves for a maximally deformed crust is found to be greater than the observational upper limits from LIG...

  12. The mechanical and strength properties of diamond.

    Science.gov (United States)

    Field, J E

    2012-12-01

    Diamond is an exciting material with many outstanding properties; see, for example Field J E (ed) 1979 The Properties of Diamond (London: Academic) and Field J E (ed) 1992 The Properties of Natural and Synthetic Diamond (London: Academic). It is pre-eminent as a gemstone, an industrial tool and as a material for solid state research. Since natural diamonds grew deep below the Earth's surface before their ejection to mineable levels, they also contain valuable information for geologists. The key to many of diamond's properties is the rigidity of its structure which explains, for example, its exceptional hardness and its high thermal conductivity. Since 1953, it has been possible to grow synthetic diamond. Before then, it was effectively only possible to have natural diamond, with a small number of these found in the vicinity of meteorite impacts. Techniques are now available to grow gem quality synthetic diamonds greater than 1 carat (0.2 g) using high temperatures and pressures (HTHP) similar to those found in nature. However, the costs are high, and the largest commercially available industrial diamonds are about 0.01 carat in weight or about 1 mm in linear dimension. The bulk of synthetic diamonds used industrially are 600 µm or less. Over 75% of diamond used for industrial purposes today is synthetic material. In recent years, there have been two significant developments. The first is the production of composites based on diamond; these materials have a significantly greater toughness than diamond while still maintaining very high hardness and reasonable thermal conductivity. The second is the production at low pressures by metastable growth using chemical vapour deposition techniques. Deposition onto non-diamond substrates was first demonstrated by Spitsyn et al 1981 J. Cryst. Growth 52 219-26 and confirmed by Matsumoto et al 1982 Japan J. Appl. Phys. 21 L183-5. These developments have added further to the versatility of diamond. Two other groups of

  13. Influence of Carbonation on Mechanical Properties of Concrete

    Institute of Scientific and Technical Information of China (English)

    梁发云; 陈龙珠; 李检保

    2003-01-01

    As one of the most important factors that determine the lifespan of a reinforced concrete structure, car-bonation not only corrodes the reinforcing steel, but also changes the mechanical properties of concrete. For betterunderstanding the performance of carbonated concrete structure, it is necessary to study the mechanical propertiesof carbonated concrete. The strees-strain relationship of carbonated concrete was analyzed on the basis of experi-ments. The specimens were made by means of accelerated carbonation and then compressed on the testing ma-chine. Some very important characteristics of carbonated concrete were revealed by the testing results. In addition,a useful constitutive model of carbonated concrete, which proved to be suitable for analyzing carbonated concretemembers, was established in this research.

  14. Hydrodynamic interaction induced mechanical properties of SGF reinforced polyethersulfone

    Science.gov (United States)

    Munirathnamma, L. M.; Ningaraju, S.; Kumar, K. V. Aneesh; Ravikumar, H. B.

    2016-05-01

    In order to explore the effect of short glass fiber (SGF) reinforcement on the mechanical properties of Polyethersulfone (PES), short glass fibers of different proportion (10 - 40 wt %) are reinforced into PES matrix. The free volume distribution of SGFR-PES composites derived from CONTIN-PALS2 program exhibits the narrow full width at half maximum (FWHM). This is attributed to the improved adhesion resulted by the hydrodynamic interaction between the polymeric chains of PES matrix and SGF. The hydrodynamic interaction parameter (h) decreases as a function of SGF wt% and becomes more negative for 40 wt% SGFR-PES composites suggest the generation of excess friction at the interface. This improves the adhesion between the polymeric chains of PES matrix and SGF and hence the mechanical strength of the SGFR-PES composites.

  15. Microstructure and Mechanical Properties of Graphene Oxide/Copper Composites

    Directory of Open Access Journals (Sweden)

    HONG Qi-hu

    2016-09-01

    Full Text Available Graphene oxide/copper (GO/Cu composites were successfully synthesized through the ball milling and vacuum hot press sintering process. The morphologies of the mixture powders, and the microstructure and mechanical properties of GO/Cu composites were investigated by OM, SEM, XRD, hardness tester and electronic universal testing machine, respectively. The results show that the GO/Cu composites are compact. Graphene oxide with flake morphology is uniformly dispersed and well consolidated with copper matrix. When the mass fraction of graphene oxide is 0.5%, the microhardness and compress strength at RT reach up to 63HV and 276MPa, increased by 8.6% and 28%, respectively. The strengthening mechanism is load transfer effect, dislocation strengthening and fine crystal reinforcing.

  16. Laser welding of polymers, compatibility and mechanical properties

    DEFF Research Database (Denmark)

    Nielsen, Steen Erik; Strange, Marianne; Kristensen, Jens Klæstrup

    2013-01-01

    with the development of related absorbers added to the polymer materials provide the possibility of joining transparent and non-transparent materials. The automotive industry, the medical device industry and the electronic industry are just some of the areas where the technology is widely implemented......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....... There is an increasing industrial interest in joining dissimilar polymers. To overcome the challenges involved increased focus is set on the understanding of joining mechanisms, morphology and molecular structure behavior. Also the understanding of resulting mechanical and thermal properties is presently subject...

  17. Mechanical Properties of Intermediate Filament Proteins.

    Science.gov (United States)

    Charrier, Elisabeth E; Janmey, Paul A

    2016-01-01

    Purified intermediate filament (IF) proteins can be reassembled in vitro to produce polymers closely resembling those found in cells, and these filaments form viscoelastic gels. The cross-links holding IFs together in the network include specific bonds between polypeptides extending from the filament surface and ionic interactions mediated by divalent cations. IF networks exhibit striking nonlinear elasticity with stiffness, as quantified by shear modulus, increasing an order of magnitude as the networks are deformed to large strains resembling those that soft tissues undergo in vivo. Individual IFs can be stretched to more than two or three times their resting length without breaking. At least 10 different rheometric methods have been used to quantify the viscoelasticity of IF networks over a wide range of timescales and strain magnitudes. The mechanical roles of different classes of cytoplasmic IFs on mesenchymal and epithelial cells in culture have also been studied by an even wider range of microrheological methods. These studies have documented the effects on cell mechanics when IFs are genetically or pharmacologically disrupted or when normal or mutant IF proteins are exogenously expressed in cells. Consistent with in vitro rheology, the mechanical role of IFs is more apparent as cells are subjected to larger and more frequent deformations.

  18. Mechanical properties of alumina porcelain during heating

    Science.gov (United States)

    Šín, Peter; Podoba, Rudolf; ŠtubÅa, Igor; Trník, Anton

    2014-11-01

    The mechanical strength and Young's modulus of green alumina porcelain (50 wt. % of kaolin, 25 wt. % of Al2O3, and 25 wt. % of feldspar) were measured during heating up to 900 °C and 1100 °C, respectively. To this end, we used the three point-bending method and modulated force thermomechanical analysis (mf-TMA). The loss liberation - of the physically bound water (20 - 250 °C) strengthens the sample and Young's modulus increases its values significantly. The dehydroxylation that takes place in the range of 400 - 650 °C causes a slight decrease in Young's modulus. On the other hand, the mechanical strength slightly increases in this temperature range, although it has a sudden drop at 420 °C. Beyond the dehydroxylation range, above 650 °C, both Young's modulus and mechanical strength increase. Above 950 °C, a sharp increase of Young's modulus is caused by the solid-state sintering and the new structure created by the high-temperature reactions in metakaolinite.

  19. MECHANICAL PROPERTIES OF SHIRASU TUNNEL TAKEN ACCOUNT OF GEOTECHNICAL PROPERTIES OF SHIRASU GROUND

    Science.gov (United States)

    Taho, Toru; Suzuki, Masayuki; Sugawara, Kentaro; Kitamura, Ryosuke

    Shirasu which is defined as the non-welded part of pyroclastic flow deposits is widely distributed in the southern part of Kyushu Island. Shirasu is regarded as a soft ground when the mountain tunneling method is applied because its unconfined compression strength is only 20-100 kN/m2. Nevertheless, it is well known among the practical engineers that Shirasu tunnel is stable. In this paper the mechanical properties of Shirasu tunnel was analyzed, taking account of the geotechnical properties of Shirasu ground, where the laboratory and in-situ tests were carried out with the field measurement in tunnel. Furthermore the numerical experiment by FDM was also performed by using the proposed nonlinear mechanical model for Shirasu ground to compare the numerical results with those obtained from the field measurement.

  20. Mechanical properties of silver matrix composites reinfroced with ceramic particles

    Directory of Open Access Journals (Sweden)

    J. Śleziona

    2006-04-01

    Full Text Available Purpose: Silver, silver alloys, as well as silver matrix based composites have been well known and applied in the electrotechnical and electronics industry for several decades. For many applications in electrotechnology, including electric contacts and brushes, unreinforced sliver alloys do not meet the requirements concerning mainly durability and wear resistance, first of all to tribological and electroerosive wear. These wear processes may be prevented by introducing to silver reinforcement particles and alloys. The target of the research included basic mechanical properties determination of the silver matrix composites reinforced with ceramic particles, manufactured with the use of suspension methods.Design/methodology/approach: In the presented paper the authors demonstrate possibilities of manufacturing of silver matrix composites on the way of casting technology utilization.Findings: The results of the research prove that applied suspension technology, based on introducing of agglomerated foundry alloy which is the carrier for reinforcement particles (SiC lub Al2O3 allows to produce in an effective and, what is important, in an economically attractive way, sliver alloys based composites.Research limitations/implications: The researches on the structure of manufactured composites and their mechanical properties that are presented in the paper prove the possibilities of mechanical mixing technology application for producing mechanical and stable connection between silver matrix and ceramic particles of aluminium oxide and silicon carbide.Originality/value: The manufacturing of this type of composites is based most of all on the utilization of powder metallurgy techniques. However the obtained results of the research prove that there is a possibility of silver matrix composites forming in the casting and plastic working processes. Extrusion process carried out in the hydraulic press KOBO has its favourably influence on ceramic reinforcement

  1. Mechanical Properties of Semiconductors and Their Alloys

    Science.gov (United States)

    1992-02-01

    enough footing to warrant refereed publication. 14 3. FIRST-PRINCIPLES APPROACH TO THE PLASTIC PROPERTIES OF HIGH-TEMPERATURE ALLOYS 3.1 INTRODUCTION With...10.2 9.8 10.274 C" 8.036 8.3 3.5 8.013 drC =(a/4)[l+(l-) 2+P2]’. C11 11.1 11.30 C 0.54 0.51 0.53 0.51 A similar procedure can now be carried out to...In CP structure, the first values dAc and dRc are for those bonds along the (111)direction, and the second values are for those in the other three

  2. Mechanical properties of sand, silt, and clay containing tetrahydrofuran hydrate

    Science.gov (United States)

    Yun, T.S.; Santamarina, C.J.; Ruppel, C.

    2007-01-01

    The mechanical behavior of hydrate-bearing sediments subjected to large strains has relevance for the stability of the seafloor and submarine slopes, drilling and coring operations, and the analysis of certain small-strain properties of these sediments (for example, seismic velocities). This study reports on the results of comprehensive axial compression triaxial tests conducted at up to 1 MPa confining pressure on sand, crushed silt, precipitated silt, and clay specimens with closely controlled concentrations of synthetic hydrate. The results show that the stress-strain behavior of hydrate-bearing sediments is a complex function of particle size, confining pressure, and hydrate concentration. The mechanical properties of hydrate-bearing sediments at low hydrate concentration (probably 50% of pore space), the behavior becomes more independent of stress because the hydrates control both stiffness and strength and possibly the dilative tendency of sediments by effectively increasing interparticle coordination, cementing particles together, and filling the pore space. The cementation contribution to the shear strength of hydrate-bearing sediments decreases with increasing specific surface of soil minerals. The lower the effective confining stress, the greater the impact of hydrate formation on normalized strength.

  3. Simultaneous spectrophotometric and mechanical property characterization of skin

    Science.gov (United States)

    Bunegin, Leonid; Moore, Jeffery B.

    2006-02-01

    Both reflectance spectroscopy and the determination Young's Modulus of skin have shown promise for identifying skin pathology. At present, these determinations are carried out using separate methodologies. This study demonstrates a new technology combining digital UV/VIS reflectance spectroscopy and vacuum aspiration for simultaneously determining the reflectance spectrum and mechanical properties of human skin tissue. A small hand held prototype device incorporating fiber-optic light guides into a vacuum channel was calibrated using various elastic materials subjected to increments of stress by vacuum from 0 to 25 in Hg. The intensity of a UV/VIS light beam reflected from the material at each vacuum increment was compared to the resulting material strain. The reflected beam was also spectrophotometrically analyzed. Skin types were similarly evaluated comparing normal and scar tissue and skin of various ages and coloration. An exponential relationship between reflected beam intensity and the amount of strain resulting from vacuum increments was observed. Young's Modulus (calculated from Aoki et. al equation) and spectra from normal skin and scar tissue were in agreement with previously published observations. Age related decreases in skin elasticity were also demonstrated. In the reflectance spectra, oxy and deoxy-hemoglobin absorbance bands were detected, becoming significantly enhanced at increased levels of vacuum. Melanin absorbance was also easily detected and appeared to correlate with skin coloration. Since superficial skin pathologies have characteristic spectroscopic and mechanical properties, this technique may provide a promising new approach for rapid, non-invasive method for the evaluation of skin lesions.

  4. Mechanical properties of niobium radio-frequency cavities

    Energy Technology Data Exchange (ETDEWEB)

    Ciovati, G., E-mail: gciovati@jlab.org [Thomas Jefferson National Accelerator Facility, 12000 Jefferson Avenue, Newport News, VA 23606 (United States); Dhakal, P.; Matalevich, J.; Myneni, G. [Thomas Jefferson National Accelerator Facility, 12000 Jefferson Avenue, Newport News, VA 23606 (United States); Schmidt, A.; Iversen, J.; Matheisen, A.; Singer, W. [Deutsches Elektronen-Synchrotron, Notkestraße 85, 22607 Hamburg (Germany)

    2015-08-26

    Radio-frequency cavities made of bulk niobium are one of the components used in modern particle accelerators. The mechanical stability is an important aspect of cavity design, which typically relies on finite-element analysis simulations using material properties from tensile tests on sample. This contribution presents the results of strain and resonant frequency measurements as a function of a uniform pressure up to 620 kPa, applied to single-cell niobium cavities with different crystallographic structure, purity and treatments. In addition, burst tests of high-purity multi-cell cavities with different crystallographic structures have been conducted up to the tensile strength of the material. Finite-element analysis of the single-cell cavity geometry is in good agreement with the observed behavior in the elastic regime assuming a Young’s modulus value of 88.5 GPa and a Poisson’s ratio of 0.4, regardless of crystallographic structure, purity or treatment. However, the measured yield strength and tensile strength depend on crystallographic structure, material purity and treatment. In particular, the results from this study show that the mechanical properties of niobium cavities made from ingot material with large crystals are comparable to those of cavities made of fine-grain niobium.

  5. Analysis of Mechanical Properties of Fabrics of Different Raw Material

    Directory of Open Access Journals (Sweden)

    Aušra ADOMAITIENĖ

    2011-07-01

    Full Text Available The study analyzes dependence of mechanical properties (breaking force, elongation at break, static friction force and static friction coefficient on integrated fabric structure factor j and raw material density r, among the fabrics of different raw material (cotton, wool, polypropylene, polyester and polyacrylnitrile and woven in different conditions. The received results demonstrate that sometimes strong dependences exist (wool, polypropylene and polyacrylnitrile, whereas in some cases (cotton and polyester there is no correlation. It was also discovered that the breaking force and elongation at break in the direction of weft increase, when fabric structure becomes more rigid. In the meantime variations of the curves in the direction of warp are insignificant. Regarding static friction force and static friction coefficient (found in two cases, when fabrics were rubbing against leather and materials, it was discovered that consistency of the curves is irregular, i. e. they either increase or decrease, when integrated fabric structure factor j growth. It was also identified that some dependences are not strong and relationship between explored and analyzed factors does not exist. Variation of all these mechanical properties with respect to material density r enables to conclude that increase of material density r results in poor dependences or they are whatsoever non-existent.http://dx.doi.org/10.5755/j01.ms.17.2.487

  6. Prediction of mechanical properties of hot rolled steel products

    Directory of Open Access Journals (Sweden)

    P. Šimeček

    2007-01-01

    Full Text Available Purpose: Model for prediction of mechanical properties of rolled steel products after final cooling from exitrolling temperature is one of the basic component of any software for complex computer simulation of rollingtechnologies. Theoretical background and implementation of such software tool is described.Design/methodology/approach: After calculation of cooling curves by any technology dependent Shell thesoftware tool MECHP can be called to predict CCT Diagram from current chemical composition of steel andinitial properties of deformed austenite first than structure shares (percentage of ferrite, pearlite, bainite andmartensite resulting from austenite decomposition process for given cooling curve and finally mechanicalproperties of final product after cooling (hardness, yield stress, tensile strength are calculated. Implementationof MECHP tool into the software RollFEM3D for 3D Finite Elements Method simulation of rolling processesis presented.Findings: Comparison of MECHP calculations with measured process data (water cooling and subsequent aircooling of hot rolled narrow plate and wire shows correspondence that is satisfactory for using in control ofprocess cooling technology.Practical implications: Results of verification showed that the software tool MECHP is implementable asa postprocessor into off-line rolling process simulation software or can be used as a mechanical propertiespredictor in software for on-line control of cooling.Originality/value: Developing of technology independent Library solving the problem of final mechanicalproperties prediction for various kinds of rolling technologies.

  7. Dynamic mechanical and swelling properties of maleated hyaluronic acid hydrogels.

    Science.gov (United States)

    Lin, Hai; Liu, Jun; Zhang, Kai; Fan, Yujiang; Zhang, Xingdong

    2015-06-05

    A series of maleated hyaluronan (MaHA) are developed by modification with maleic anhydride. The degrees of substitution (DS) of MaHA vary between 7% and 75%. The DS of MaHA is both higher and wider than methacrylated HA derivatives (MeHA) reported in the literature. MaHA hydrogels are then prepared by photopolymerization and their dynamic mechanical and swelling properties of the hydrogels are investigated. The results showed that MaHA hydrogels with moderate DS (25%, 50% and 65%) have higher storage modulus and lower equilibrium swelling ratios than those with either low or high DS (7%, 15% and 75%). Theoretical analyses also suggest a similar pattern among hydrogels with different DS. The results confirm that the increased cross-linking density enhances the strength of hydrogels. Meanwhile, the hydrophilicity of introduced groups during modification and the degree of incomplete crosslinking reaction might have negative impact on the mechanical and swelling properties of MaHA hydrogels.

  8. Mechanical properties of several Fe-Ni meteorites

    Energy Technology Data Exchange (ETDEWEB)

    Mulford, Roberta N [Los Alamos National Laboratory; El - Dasher, Bassem [LLNL

    2010-10-28

    The strength and elastic constants of meteorites are of increasing interest as predictions of meteorite impacts on earth come within the realm of possibility. In addition, meteorite impacts on extraterrestrial bodies provide an excellent sampling tool for evaluation of planetary compositions and properties. Fe-Ni meteorites provide a well-defined group of materials of fairly uniform composition. Iron-nickel meteorites exhibit a unique lamellar microstructure, a Widmanstatten structure, consisting of small regions with steep-iron-nickel composition gradients. This microstructure is found in the Fe-Ni system only in meteorites, and is believed to arise as a result of slow cooling in a planetary core or other large mass. Meteorites with compositions consisting of between 5 and 17% nickel in iron are termed 'octahedrite,' and further characterized according to the width of the Ni-poor kamacite bands; 'fine,' (0.2-0.5 mm) 'medium,' (0.5-1.3 mm) and 'coarse,' (1.5-3.3 mm). Many meteorites have inclusions and structures indicating that the material has been shocked at some point early in its evolution. Several Iron-nickel meteorites have been examined using Vickers and spherical indentation, x-ray fluorescence, and EBSD. Direct observation of mechanical properties in these highly structured materials provides a valuable supplement to bulk measurements, which frequently exhibit large variation in dynamic properties, even within a single sample. Previous studies of the mechanical properties of a typical iron-nickel meteorite, a Diablo Canyon specimen, indicated that the strength of the composite was higher by almost an order of magnitude than values obtained from laboratory-prepared specimens. Additional meteorite specimens have been examined to establish a range of error on the previously measured yield, to determine the extent to which deformation upon re-entry contributes to yield, and to establish the degree to which the strength

  9. Thermobimetals Mechanical Properties Produced by Explosive Welding with Rolling

    OpenAIRE

    Gulbin, V.; Kobelev, A.; Borissov, D.

    1997-01-01

    We used explosive welding with rolling to produce thermobimetals on the basis of beryllium bronze and alloys of nickel. It gave us possibility to obtain magnetic and non-magnetic thermobimetals possessing high physical and mechanical properties.

  10. 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 viny

  11. 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.

  12. Mechanical Properties and Solidiifed Mechanism of Tailings Mortar with Waste Glass

    Institute of Scientific and Technical Information of China (English)

    NING Baokuan; XU Jingwen; CHEN Sili

    2015-01-01

    In order to improve the comprehensive utilization of solid waste such as iron tailings and waste glass and so on, mechanical property test of cement tailings mortar mixed waste glass and curing mechanism research were conducted in the key materials mechanics lab of Liaoning province. The experimental results show that adding waste glass particles can improve the grain size distribution of tailings. The effect is proportional to the content. The compressive strength of tailings mortar has increased signiifcantly. The ifneness modulus of tailings mortar mixture adding waste glass powder was gradually reducing with the increase of the dosage of waste glass powder, but the compressive strength of the mixture has gradually enhanced with the increase of the dosage. Microscopic analysis shows that the waste glass particles in the mortar mainly play a role of coarse aggregate and glass powder after grinding fine below a certain size shows strong volcanic activity, which can act hydration with tailings, at the same time glass powder also, plays a role in ifne aggregate iflling. Therefore, all of glass particles and glass powder can be used as the additive material for improving and optimizing the mechanical property of tailings mortar.

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

    OpenAIRE

    Başdoğan, Çağatay; Yarpuzlu, Berkay; Ayyıldız, Mehmet; Tok, Olgu Enis; Aktaş, Ranan Gülhan

    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 mechanica...

  14. Dynamic mechanical properties of an inlay composite.

    Science.gov (United States)

    Dionysopoulos, P; Watts, D C

    1989-06-01

    A visible light-cured composite resin (Brilliant DI) has been studied over a wide range of temperature and frequency by a dynamic mechanical flexural method. The derived data of logarithmic modulus and loss tangent (tan delta) show considerable changes following a secondary-cure process applied to the material. This involved the application of heat and intense light with temperatures rising to 120 degrees C in 7 min. Following this oven-cure the resin phase exhibited enhanced stiffness with the activation-energy barrier for molecular motion at the glass-transition rising from 220 to 291 kJ/mol. This study clarifies the nature and extent of the internal molecular changes which may be produced in the fabrication of a composite inlay.

  15. Dynamical Mechanical Properties for AD90 Alumina

    Institute of Scientific and Technical Information of China (English)

    REN Hui-lan; NING Jian-guo; LI Ping

    2007-01-01

    The dynamic response of polycrystalline alumina was investigated in the pressure range of 0 -13 GPa by planar impact experiments.Velocity interferometer system for any reflector(VISAR) was used to obtain free surface velocity profile and determine the Hugoniot elastic limit,and manganin gauges were employed to obtain the stress-time histories and determine Hugoniot curve.Both the free surface particle velocity profiles and Hugoniot curves indicate the dispersion of the "plastic" wave for alumina.With the measured stress histories,the complete histories of strain,particle velocity,specific volume and specific internal energy are gained by using path line principle of Lagrange analysis.The dynamic mechanical behaviors for alumina under impact loading are analyzed,such as nonlinear characteristic,strain rate dependence,dispersion and declination of shock wave in the material.

  16. Chitosan fibers with improved biological and mechanical properties for tissue engineering applications.

    Science.gov (United States)

    Albanna, Mohammad Z; Bou-Akl, Therese H; Blowytsky, Oksana; Walters, Henry L; Matthew, Howard W T

    2013-04-01

    The low mechanical properties of hydrogel materials such as chitosan hinder their broad utility for tissue engineering applications. Previous research efforts improved the mechanical properties of chitosan fiber through chemical and physical modifications; however, unfavorable toxicity effects on cells were reported. In this paper, we report the preparation of chitosan fibers with improved mechanical and biocompatibility properties. The structure-property relationships of extruded chitosan fibers were explored by varying acetic acid (AA) concentration, ammonia concentration, annealing temperature and degree of heparin crosslinking. Results showed that optimizing AA concentration to 2vol% improved fiber strength and stiffness by 2-fold. Extruding chitosan solution into 25wt% of ammonia solution reduced fiber diameters and improved fiber strength by 2-fold and stiffness by 3-fold, due to an increase in crystallinity as confirmed by XRD. Fiber annealing further reduced fiber diameter and improved fiber strength and stiffness as temperature increased. Chitosan fibers crosslinked with heparin had increased diameter but lower strength and stiffness properties and higher breaking strain values. When individual parameters were combined, further improvement in fiber mechanical properties was achieved. All mechanically improved fibers and heparin crosslinked fibers promoted valvular interstitial cells (VIC) attachment and growth over 10 day cultures. Our results demonstrate the ability to substantially improve the mechanical properties of chitosan fibers without adversely affecting their biological properties. The investigated treatments offer numerous advantages over previous physical/chemical modifications and thus are expected to expand the utility of chitosan fibers with tunable mechanical properties in various tissue engineering applications.

  17. Mechanical properties of forgings depending on the changes in shape and chemical composition of inclusions

    Directory of Open Access Journals (Sweden)

    O. Híreš

    2010-10-01

    Full Text Available The article deals with mechanical properties of forgings used for special technology in cannon barrels production. The forgings are treated by elctroslag remelting technology (ESR to enhance its plastic properties and yield point. Described experiments are focused on mechanical properties and metallurgical quality (microstructure of steels from which are the forgings made. The article includes microstructure photographs and description of inclusions located in examined steels. Experimental results compare forgings treated by ESR and next ones without ESR.

  18. Genetic and environmental modification of the mechanical properties of wood

    Science.gov (United States)

    Sederoff, R.; Allona, I.; Whetten, R.

    1996-02-01

    Wood is one of the nation's leading raw materials and is used for a wide variety of products, either directly as wood, or as derived materials in pulp and paper. Wood is a biological material and evolved to provide mechanical support and water transport to the early plants that conquered the land. Wood is a tissue that results from the differentiation and programmed cell death of cells that derive from a tissue known as the vascular cambium. The vascular cambium is a thin cylinder of undifferentiated tissue in plant stems and roots that gives rise to several different cell types. Cells that differentiate on the internal side of the cambium form xylem, a tissue composed in major part, of long thin cells that die leaving a network of interconnected cell walls that serve to transport water and to provide mechanical support for the woody plant. The shape and chemical composition of the cells in xylem are well suited for these functions. The structure of cells in xylem determines the mechanical properties of the wood because of the strength derived from the reinforced matrix of the wall. The hydrophobic phenolic surface of the inside of the cell walls is essential to maintain surface tension upon which water transport is based and to resist decay caused by microorganisms. The properties of wood derived from the function of xylem also determine its structural and chemical properties as wood and paper products. Therefore, the physical and chemical properties of wood and paper products also depend on the morphology and composition of the cells from which they are derived. Wood (xylem cell walls) is an anisotropic material, a composite of lignocellulose. It is a matrix of cellulose microfibrils, complexed with hemicelluloses, (carbohydrate polymers which contain sugars other than glucose, both pentoses and hexoses), embedded together in a phenolic matrix of lignin. The high tensile strength of wood in the longitudinal direction, is due to the structure of cellulose and the

  19. ELECTRICAL AND MECHANICAL PROPERTIES OF POLYANILINE FILMS-EFFECT OF NEUTRAL SALTS ADDED DURING POLYMERIZATION

    Institute of Scientific and Technical Information of China (English)

    1998-01-01

    The electrical and mechanical properties of polyaniline (PANI) films synthesized by the presence of the selected neutral salts in the polymerization were measured as a function of the properties and the concentration of the selected neutral salts, and the protonation state. It was found that both the electrical and mechanical properties of PANI films were enhanced by adding neutral salts in the polymerization. The adding of the neutral salts in the polymerization resulted in extended conformation of polymer chain and increasing of molecular weight of PANI, which may be the reasons why the electrical and mechanical properties of PANI films were improved by the presence of neutral salts in the polymerization.

  20. Effect of extrusion processing on the microstructure, mechanical properties, biocorrosion properties and antibacterial properties of Ti-Cu sintered alloys.

    Science.gov (United States)

    Zhang, Erlin; Li, Shengyi; Ren, Jing; Zhang, Lan; Han, Yong

    2016-12-01

    Ti-Cu sintered alloys, Ti-Cu(S) alloy, have exhibited good anticorrosion resistance and strong antibacterial properties, but low ductility in previous study. In this paper, Ti-Cu(S) alloys were subjected to extrusion processing in order to improve the comprehensive property. The phase constitute, microstructure, mechanical property, biocorrosion property and antibacterial activity of the extruded alloys, Ti-Cu(E), were investigated in comparison with Ti-Cu(S) by X-ray diffraction (XRD), optical microscopy (OM), scanning electronic microscopy (SEM) with energy disperse spectroscopy (EDS), mechanical testing, electrochemical testing and plate-count method in order to reveal the effect of the extrusion process. XRD, OM and SEM results showed that the extrusion process did not change the phase constitute but refined the grain size and Ti2Cu particle significantly. Ti-Cu(E) alloys exhibited higher hardness and compressive yield strength than Ti-Cu(S) alloys due to the fine grain and Ti2Cu particles. With the consideration of the total compressive strain, it was suggested that the extrusion process could improve the ductility of Ti-Cu alloy(S) alloys. Electrochemical results have indicated that the extrusion process improved the corrosion resistance of Ti-Cu(S) alloys. Plate-count method displayed that both Ti-Cu(S) and Ti-Cu(E) exhibited strong antibacterial activity (>99%) against S. aureus. All these results demonstrated that hot forming processing, such as the extrusion in this study, refined the microstructure and densified the alloy, in turn improved the ductility and strength as well as anticorrosion properties without reduction in antibacterial properties.

  1. Ultrasonic investigation of mechanical properties of double base rocket propellants

    NARCIS (Netherlands)

    Schroeff, J.A. van der; Boer, R.S. de

    1976-01-01

    For a series of double base rocket propellants and for poly-methylmethacrylate (PMMA) the longitudinal and transverse sound wave velocities are measured at a frequency of 0.351 MHz in t h e temperature range of −40°C to +60°C. The relations between these acoustic properties and mechanical properties

  2. Mechanical properties of short-flax-fibre reinforced compounds

    NARCIS (Netherlands)

    Bos, H.L.; Müssig, J.; Oever, van den M.J.A.

    2006-01-01

    The mechanical properties of flax/polypropylene compounds, manufactured both with a batch kneading and an extrusion process were determined and compared with the properties of Natural fibre Mat Thermoplastic (NMT) composites. The fibre length and width distributions of the fibres from the compounds

  3. Learned dictionaries for sparse image representation: properties and results

    Science.gov (United States)

    Skretting, Karl; Engan, Kjersti

    2011-09-01

    Sparse representation of images using learned dictionaries have been shown to work well for applications like image denoising, impainting, image compression, etc. In this paper dictionary properties are reviewed from a theoretical approach, and experimental results for learned dictionaries are presented. The main dictionary properties are the upper and lower frame (dictionary) bounds, and (mutual) coherence properties based on the angle between dictionary atoms. Both l0 sparsity and l1 sparsity are considered by using a matching pursuit method, order recursive matching Pursuit (ORMP), and a basis pursuit method, i.e. LARS or Lasso. For dictionary learning the following methods are considered: Iterative least squares (ILS-DLA or MOD), recursive least squares (RLS-DLA), K-SVD and online dictionary learning (ODL). Finally, it is shown how these properties relate to an image compression example.

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

    OpenAIRE

    M. Zielińska; Kubiak, K.; 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...

  5. Towards the feasibility of using ultrasound to determine mechanical properties of tissues in a bioreactor

    Science.gov (United States)

    Mansour, Joseph M.; Gu, Di-Win Marine; Chung, Chen-Yuan; Heebner, Joseph; Althans, Jake; Abdalian, Sarah; Schluchter, Mark D.; Liu, Yiying; Welter, Jean F.

    2016-01-01

    Introduction Our ultimate goal is to non-destructively evaluate mechanical properties of tissue-engineered (TE) cartilage using ultrasound (US). We used agarose gels as surrogates for TE cartilage. Previously, we showed that mechanical properties measured using conventional methods were related to those measured using US, which suggested a way to non-destructively predict mechanical properties of samples with known volume fractions. In this study, we sought to determine whether the mechanical properties of samples, with unknown volume fractions could be predicted by US. Methods Aggregate moduli were calculated for hydrogels as a function of SOS, based on concentration and density using a poroelastic model. The data were used to train a statistical model, which we then used to predict volume fractions and mechanical properties of unknown samples. Young's and storage moduli were measured mechanically. Results The statistical model generally predicted the Young's moduli in compression to within mechanically measured value. We defined positive linear correlations between the aggregate modulus predicted from US and both the storage and Young's moduli determined from mechanical tests. Conclusions Mechanical properties of hydrogels with unknown volume fractions can be predicted successfully from US measurements. This method has the potential to predict mechanical properties of TE cartilage non-destructively in a bioreactor. PMID:25092421

  6. MECHANICAL AND THERMO–MECHANICAL PROPERTIES OF BI-DIRECTIONAL AND SHORT CARBON FIBER REINFORCED EPOXY COMPOSITES

    Directory of Open Access Journals (Sweden)

    G. AGARWAL

    2014-10-01

    Full Text Available This paper based on bidirectional and short carbon fiber reinforced epoxy composites reports the effect of fiber loading on physical, mechanical and thermo-mechanical properties respectively. The five different fiber loading, i.e., 10wt. %, 20wt. %, 30wt. %, 40wt. % and 50wt. % were taken for evaluating the above said properties. The physical and mechanical properties, i.e., hardness, tensile strength, flexural strength, inter-laminar shear strength and impact strength are determined to represent the behaviour of composite structures with that of fiber loading. Thermo-mechanical properties of the material are measured with the help of Dynamic Mechanical Analyser to measure the damping capacity of the material that is used to reduce the vibrations. The effect of storage modulus, loss modulus and tan delta with temperature are determined. Finally, Cole–Cole analysis is performed on both bidirectional and short carbon fiber reinforced epoxy composites to distinguish the material properties of either homogeneous or heterogeneous materials. The results show that with the increase in fiber loading the mechanical properties of bidirectional carbon fiber reinforced epoxy composites increases as compared to short carbon fiber reinforced epoxy composites except in case of hardness, short carbon fiber reinforced composites shows better results. Similarly, as far as Loss modulus, storage modulus is concerned bidirectional carbon fiber shows better damping behaviour than short carbon fiber reinforced composites.

  7. Porosity and mechanical properties of zirconium ceramics

    Energy Technology Data Exchange (ETDEWEB)

    Buyakova, S., E-mail: sbuyakova@ispms.tsc.ru; Kulkov, S. [Tomsk State University (Russian Federation); Tomsk Polytechnic University (Russian Federation); Institute of Strength Physics and Materials Science RAS (Russian Federation); Sablina, T. [Institute of Strength Physics and Materials Science RAS (Russian Federation)

    2015-11-17

    Has been studied a porous ceramics obtained from ultra-fine powders. Porous ceramic ZrO{sub 2}(MgO), ZrO{sub 2}(Y{sub 2}O{sub 3}) powder was prepared by pressing and subsequent sintering of compacts homologous temperatures ranging from 0.63 to 0.56 during the isothermal holding duration of 1 to 5 hours. The porosity of ceramic samples was from 15 to 80%. The structure of the ceramic materials produced from plasma-sprayed ZrO{sub 2} powder was represented as a system of cell and rod structure elements. Cellular structure formed by stacking hollow powder particles can be easily seen at the images of fracture surfaces of obtained ceramics. There were three types of pores in ceramics: large cellular hollow spaces, small interparticle pores which are not filled with powder particles and the smallest pores in the shells of cells. The cells generally did not have regular shapes. The size of the interior of the cells many times exceeded the thickness of the walls which was a single-layer packing of ZrO{sub 2} grains. A distinctive feature of all deformation diagrams obtained in the experiment was their nonlinearity at low deformations which was described by the parabolic law. It was shown that the observed nonlinear elasticity for low deformation on deformation diagrams is due to mechanical instability of the cellular elements in the ceramic carcass.

  8. Experimental study on mechanical properties of aircraft honeycomb sandwich structures

    Directory of Open Access Journals (Sweden)

    Talebi Mazraehshahi H.

    2010-06-01

    Full Text Available Mechanical behaviour of sandwich panels under different conditions have been exprimentally studied in this research to increase the knowledge of aircraft sandwich panel structures and facilitate design criteria for aircraft structures. Tests were concentrated on the honeycomb sandwich structures under different loads including flexural, insert shear, flat wise tension and compression loads. Furthermore, effect of core density and face material on mechanical behavior of different samples were investigated and compared with analytical and FEM method. Effects of skin thickness on strength of honycomb sandwhich panels under shear pull out and moments have also been considerd in this study. According to this investigation, insert strength and flexural test under different load conditions is strongly affected by face thickness, but compression and tearoff (falt wise tensile properties of a sandwich panel depends on core material. The study concludes that the correlation between experimental results and the analytical predictions will enable the designer to predict the mechanical behaviour and strength of a sandwich beam; however, applied formula may lead engineers to unreliable results for shear modulus.

  9. Mechanical properties of bimetallic one-dimensional structures

    Science.gov (United States)

    Smelova, Ekaterina M.; Sitnikov, Ivan I.; Zelensky, Vladimir S.; Tsysar, Kseniya M.; Andreev, Valery G.; Vdovin, Vladimir A.; Saletsky, Alexander M.

    2016-12-01

    Mechanical properties of freestanding Au-Mn nanowires and Au-Mn nanowire on a Cu (110) substrate are studied with ab initio theoretical approach. The calculations were carried out using the software package Vienna Ab-initio Simulation Package (VASP), which is based on the density functional theory (DFT). It was shown that the breaking force (0.45nN) as well as the interatomic distance at a breaking point in bimetallic nanowire (3.0 Å) are higher than in one component Au wire (0.4 nN and 2.6Å respectively). Relative elongation of 15 % results in a fracture of bimetallic nanowire. We studied the mechanical response of the nanojunction in a form of three-atomic Au chain aligned vertically between two pyramidal gold electrodes and demonstrated that the breaking of nanocontact depends only the interaction between Au atoms in the chain and dependents slightly on the structure and properties of the atomic structure of the electrodes.

  10. Mechanical properties of some polymer materials used for tooth positioners.

    Science.gov (United States)

    Collett, A R; Cook, W D; West, V C

    1994-10-01

    The chemical composition, thermal behaviour and mechanical properties of three tooth positioner materials, Urethane P1 (P1), White Rubber (WR) and Elastocryl (EL) were investigated. Infra-red spectrophotometry indicated the P1 polyurethane material to be of the polyether type, and EL to be a blend of poly(ethyl methacrylate) and poly(methyl methacrylate) while WR appeared to be filled cis-poly (isoprene) (natural rubber). The glass transition temperature (Tg) for EL was determined as approximately 10 degrees C, and for both P1 and WR the Tg was less than -50 degrees C. The stress relaxation behaviour was assessed in compression by measuring the stress variation with time. The results for all three materials conformed to the superelastic theory of rubber elasticity. EL exhibited both a more rapid rate and higher degree of stress relaxation than did P1 and WR. Recovery from deformation was assessed by compressing cylinders for given periods of time and then measuring the level of reduced residual strain of the material with time. All three materials exhibited significant residual strain (epsilon(t)) over 'clinically relevant' time periods, and the reduced residual strain (epsilon(t)/epsilon(O)) following deformation was greater for EL than P1 or WR. There was some indication that the three materials have some permanent set following deformation. It was concluded that, in considering desirable mechanical properties of tooth positioner materials, EL is the least suitable of the three examined, with none of the materials being ideal.

  11. Mechanical properties and structure of austempered ductile iron -ADI

    Directory of Open Access Journals (Sweden)

    Krzyńska A.

    2007-01-01

    Full Text Available The results of experimental study of austempered ductile iron are presented. The aim of the investigations was to look closer into the structure – mechanical properties relationships of this very attractive cast material. The experiment was carried out with 500 7 grade ductile iron, which was austempered using different parameters of heat treatment. The specimens were first solution treated 1 hour in 910oC and then isothermally quenched for different time in silicon oil bath of temperature 275, 325, 300 and 350oC. The mechanical properties heat treated specimens were tested in tensile to evaluate yield stress Re, 0.2, tensile strength Rm and elongation A10. Additionally hardness of heat treated samples was measured using Brinell-Rockwell hardness tester. Structure of the specimens was studied either with conventional metallography, scanning (SEM and transmission (TEM electron microscopy. It followed from the study that conventional grade ductile iron enabled to produce both low and high strength ADI, depend on heat treatment parameters. As expected the low temperature isothermal quenching produced higher strength ADI compare to the same ductile iron but austempered at 350oC. It was discovered however, that low yield strength ADI obtained for short time quenching at 275oC exhibited high strengthening effect while strained in tensile. So it was concluded that this had to by cause by large amount of untransformed austenite, which FCC lattice is characterized by high strengthening coefficient.

  12. Electronic and Mechanical Properties of Hydrogenated Irradiated and Amorphous Graphene

    Science.gov (United States)

    Weerasinghe, Asanka; Ramasubramaniam, Ashwin; Maroudas, Dimitrios

    Defect engineering and chemical functionalization of graphene are promising routes for fabrication of carbon nanostructures and 2D metamaterials with unique properties and function. Here, we use hydrogenation of irradiated, including irradiation-induced amorphous, graphene as a means of studying chemical functionalization effects on its electronic structure and mechanical response. We use molecular-dynamics simulations based on a reliable bond-order potential to prepare the hydrogenated configurations and carry out dynamic deformation tests at constant strain rate and temperature. Our mechanical tests show that hydrogenation does not affect the ultimate tensile strength (UTS) of the irradiated graphene sheet if the hydrogenated C atoms remain sp2-hybridized; however, upon inducing sp3 hybridization of these C atoms, UTS decreases by about 10 GPa. Furthermore, the fracture strain of the irradiated structure decreases by up to 30% upon hydrogenation independent of the hybridization type. We also report results for the electronic structure of hydrogenated configurations based on a density-functional tight-binding approach and assess the potential for tuning the electronic properties of these defective, functionalized graphenes.

  13. Bioinspired Cellular Structures: Additive Manufacturing and Mechanical Properties

    Science.gov (United States)

    Stampfl, J.; Pettermann, H. E.; Liska, R.

    Biological materials (e.g., wood, trabecular bone, marine skeletons) rely heavily on the use of cellular architecture, which provides several advantages. (1) The resulting structures can bear the variety of "real life" load spectra using a minimum of a given bulk material, featuring engineering lightweight design principles. (2) The inside of the structures is accessible to body fluids which deliver the required nutrients. (3) Furthermore, cellular architectures can grow organically by adding or removing individual struts or by changing the shape of the constituting elements. All these facts make the use of cellular architectures a reasonable choice for nature. Using additive manufacturing technologies (AMT), it is now possible to fabricate such structures for applications in engineering and biomedicine. In this chapter, we present methods that allow the 3D computational analysis of the mechanical properties of cellular structures with open porosity. Various different cellular architectures including disorder are studied. In order to quantify the influence of architecture, the apparent density is always kept constant. Furthermore, it is shown that how new advanced photopolymers can be used to tailor the mechanical and functional properties of the fabricated structures.

  14. Hybrid polyurea elastomers with enzymatic degradation and tunable mechanical properties

    Directory of Open Access Journals (Sweden)

    Nicholas A Sears

    2016-12-01

    Full Text Available Herein, we report on the synthesis and characterization of enzymatically labile polyureas for use as a tissue-engineered ligament scaffold. Polyureas were selected due to their excellent tensile properties, fatigue resistance, and highly tunable nature. Incorporation of a collagenase-sensitive peptide into the backbone of the polyurea provided a means to confer cell-responsive degradation to the synthetic polymer. Chemical, morphological, and mechanical testing were used to confirm incorporation of the peptide and characterize polyurea films. Notably, the incorporation of the peptide resulted in an increase in modulus, elongation, and tensile strength. This was attributed to an increase in phase mixing and an increase in hydrogen bonding between the hard and soft segments. Candidate polyureas with varying levels of collagen-mimetic peptide (0%, 10%, 20% were then subjected to degradation in collagenase media or buffer at 37°C over 4 weeks. Statistically significant decreases in strength and elongation were observed in polyureas with 20% peptide content after collagenase treatment, whereas specimens in phosphate-buffered saline showed no statistically significant difference. These observations confirmed that enzyme-specific degradation was conferred to the polyurea. Overall, these polyureas hold great promise as a material for ligament reconstruction due to the promising mechanical properties and potential for cell-mediated degradation.

  15. CURING AND MECHANICAL PROPERTIES OF CHLOROSULPHONATED POLYETHYLENE RUBBER BLEND

    Directory of Open Access Journals (Sweden)

    Jaroslava Budinski-Simendić

    2011-09-01

    Full Text Available In this paper, the curing and mechanical properties of two series of prepared blends, i.e., chlorosulphonated polyethylene (CSM/isobutylene-co-isoprene (IIR rubber blends and chlorosulphonated polyethylene (CSM/chlorinated isobutylene-co-isoprene (CIIR rubber blends were carried out. Blends were prepared using a two-roll mill at a temperature of 40-50 °C. The curing was assessed using a Monsanto oscillating disc rheometer R-100. The process of vulcanization accelerated sulfur of pure rubbers and their blends was carried out in an electrically heated laboratory hydraulic press under a pressure of about 4 MPa and 160 °C. The stress-strain experiments were performed using a tensile tester machine (Zwick 1425. Results indicate that the scorch time, ts2, and optimum cure time, tc90, increase with increasing CSM content in both blends. The value of modulus at 100 and 300% elongation and tensile strength increases with increasing CSM content, whereas elongation at break shows a decreasing trend. The enhancement in mechanical properties was supported by data of crosslink density in these samples obtained from swelling measurement and scanning electron microscopy studies of the rubber blends fractured surfaces

  16. Mechanical properties of nanostructured nickel based superalloy Inconel 718

    Science.gov (United States)

    Mukhtarov, Sh; Ermachenko, A.

    2010-07-01

    This paper will describe the investigations of a nanostructured (NS) state of nickel based INCONEL® alloy 718. This structure was generated in bulk semiproducts by severe plastic deformation (SPD) via multiple isothermal forging (MIF) of a coarse-grained alloy. The initial structure consisted of γ-phase grains with disperse precipitations of γ"-phase in the forms of discs, 50-75 nm in diameter and 20 nm in thickness. The MIF generated structures possess a large quantity of non-coherent plates and rounded precipitations of δ-phase, primarily along grain boundaries. In the duplex (γ+δ) structure the grains have high dislocation density and a large number of nonequilibrium boundaries. Investigations to determine mechanical properties of the alloy in a nanostructured state were carried out. Nanocrystalline Inconel 718 (80 nm) possesses a very high room-temperature strength after SPD. Microcrystalline (MC) and NS states of the alloy were subjected to strengthening thermal treatment, and the obtained results were compared in order to determine their mechanical properties at room and elevated temperatures.

  17. In vitro indentation to determine the mechanical properties of epidermis

    NARCIS (Netherlands)

    Geerligs, M.; Van Breemen, L.; Peters, G.W.M.; Ackermans, P.A.J.; Baaijens,F.P.T.; Oomens, C.

    2011-01-01

    The lack of understanding of the mechanical behavior of the human skin layers makes the development of drug delivery using microneedles or microjets a challenging task. In particular, the key mechanical properties of the epidermis composed of stratum corneum and viable epidermis, should be better

  18. High temperature mechanical properties of iron aluminides

    Directory of Open Access Journals (Sweden)

    Morris, D. G.

    2001-04-01

    Full Text Available 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 material, 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.

    Durante los últimos años se ha prestado mucha atención a la familia de intermetálicos Fe-Al, puesto que estos constituyen un considerable potencial como materiales de ingeniería en aplicaciones a temperaturas intermedias o altas, sobre todo en casos donde se necesita alta resistencia a la oxidación o corrosión. A pesar del considerable esfuerzo desarrollado para obtener aleaciones con mejores propiedades, su resistencia mecánica a alta temperatura no es muy elevada. Se discutirán los aspectos que contribuyen a la baja resistencia mecánica a temperatura elevada en función de la estructura de dislocaciones y los mecanismos de anclaje que operan en este intermetálico. Se considerarán, también, maneras alternativas para mejorar la resistencia a temperatura elevada mediante la modificación de la microestructura y la incorporación de partículas de segunda fase.

  19. Mechanical and biological properties of keratose biomaterials.

    Science.gov (United States)

    de Guzman, Roche C; Merrill, Michelle R; Richter, Jillian R; Hamzi, Rawad I; Greengauz-Roberts, Olga K; Van Dyke, Mark E

    2011-11-01

    The oxidized form of extractable human hair keratin proteins, commonly referred to as keratose, is gaining interest as a biomaterial for multiple tissue engineering studies including those directed toward peripheral nerve, spinal cord, skin, and bone regeneration. Unlike its disulfide cross-linked counterpart, kerateine, keratose does not possess a covalently cross-linked network structure and consequently displays substantially different characteristics. In order to understand its mode(s) of action and potential for clinical translatability, detailed characterization of the composition, physical properties, and biological responses of keratose biomaterials are needed. Keratose was obtained from end-cut human hair fibers by peracetic acid treatment, followed by base extraction, and subsequent dialysis. Analysis of lyophilized keratose powder determined that it contains 99% proteins by mass with amino acid content similar to human hair cortex. Metallic elements were also found in minute quantities. Protein oxidation led to disulfide bond cleavage and drastic reduction of free thiols due to conversion of sulfhydryl to sulfonic acid, chain fragmentation, and amino acid modifications. Mass spectrometry identified the major protein constituents as a heterogeneous mixture of 15 hair keratins (type I: K31-35 and K37-39, and type II: K81-86) with small amounts of epithelial keratins which exist in monomeric, dimeric, multimeric, and even degraded forms. Re-hydration with PBS enabled molecular assembly into an elastic solid-like hydrogel. Highly-porous scaffolds formed by lyophilization of the gel had the compression behavior of a cellular foam material and reverted back to gel upon wetting. Cytotoxicity assays showed that the EC50 for various cell lines were attained at 8-10 mg/mL keratose, indicating the non-toxic nature of the material. Implantation in mouse subcutaneous tissue pockets demonstrated that keratose resorption follows a rectangular hyperbolic regression

  20. Mechanical Properties of Graphene Nanoplatelet/Carbon Fiber/Epoxy Hybrid Composites: Multiscale Modeling and Experiments

    Science.gov (United States)

    Hadden, C. M.; Klimek-McDonald, D. R.; Pineda, E. J.; King, J. A.; Reichanadter, A. M.; Miskioglu, I.; Gowtham, S.; Odegard, G. M.

    2015-01-01

    Because of the relatively high specific mechanical properties of carbon fiber/epoxy composite materials, they are often used as structural components in aerospace applications. Graphene nanoplatelets (GNPs) can be added to the epoxy matrix to improve the overall mechanical properties of the composite. The resulting GNP/carbon fiber/epoxy hybrid composites have been studied using multiscale modeling to determine the influence of GNP volume fraction, epoxy crosslink density, and GNP dispersion on the mechanical performance. The hierarchical multiscale modeling approach developed herein includes Molecular Dynamics (MD) and micromechanical modeling, and it is validated with experimental testing of the same hybrid composite material system. The results indicate that the multiscale modeling approach is accurate and provides physical insight into the composite mechanical behavior. Also, the results quantify the substantial impact of GNP volume fraction and dispersion on the transverse mechanical properties of the hybrid composite, while the effect on the axial properties is shown to be insignificant.

  1. Mechanical Properties of Graphene Nanoplatelet Carbon Fiber Epoxy Hybrid Composites: Multiscale Modeling and Experiments

    Science.gov (United States)

    Hadden, Cameron M.; Klimek-McDonald, Danielle R.; Pineda, Evan J.; King, Julie A.; Reichanadter, Alex M.; Miskioglu, Ibrahim; Gowtham, S.; Odegard, Gregory M.

    2015-01-01

    Because of the relatively high specific mechanical properties of carbon fiber/epoxy composite materials, they are often used as structural components in aerospace applications. Graphene nanoplatelets (GNPs) can be added to the epoxy matrix to improve the overall mechanical properties of the composite. The resulting GNP/carbon fiber/epoxy hybrid composites have been studied using multiscale modeling to determine the influence of GNP volume fraction, epoxy crosslink density, and GNP dispersion on the mechanical performance. The hierarchical multiscale modeling approach developed herein includes Molecular Dynamics (MD) and micromechanical modeling, and it is validated with experimental testing of the same hybrid composite material system. The results indicate that the multiscale modeling approach is accurate and provides physical insight into the composite mechanical behavior. Also, the results quantify the substantial impact of GNP volume fraction and dispersion on the transverse mechanical properties of the hybrid composite, while the effect on the axial properties is shown to be insignificant.

  2. The mechanical properties of phase separated protein droplets

    Science.gov (United States)

    Jawerth, Louise; Ijavi, Mahdiye; Patel, Avinash; Saha, Shambaditya; Jülicher, Frank; Hyman, Anthony

    In vivo, numerous proteins associate into liquid compartments by de-mixing from the surrounding solution, similar to oil molecules in water. Many of these proteins and their corresponding liquid compartments play a crucial role in important biological processes, for instance germ line specification in C. elegans or in neurodegenerative diseases such as Amyotrophic lateral sclerosis (ALS). However, despite their importance, very little is known about the physical properties of the resulting droplets as well as the physical mechanisms that control their phase separation from solution. To gain a deeper understanding of these aspects, we study a few such proteins in vitro. When these proteins are purified and added to a physiological buffer, they phase separate into droplets ranging in size from a few to tens of microns with liquid-like behavior similar to their physiological counterparts. By attaching small beads to the surface of the droplets, we can deform the droplets by manipulating the beads directly using optical tweezers. By measuring the force required to deform the droplets we determine their surface tension, elasticity and viscosity as well as the frequency response of these properties. We also measure these properties using passive micro-rheology.

  3. Enhancement of Stainless Steel's Mechanical Properties via Carburizing Process

    Science.gov (United States)

    Ahmad, S.; Alias, S. K.; Abdullah, B.; Hafiz Mohd Bakri, Mohd.; Hafizuddin Jumadin, Muhammad; Mat Shah, Muhammad Amir

    2016-11-01

    Carburizing process is a method to disperse carbon into the steel surface in order to enhance its mechanical properties such as hardness and wear resistance. This paper study investigates the effect of carburizing temperature to the carbon dispersion layer in stainless steel. The standard AISI 304 stainless steel was carburized in two different temperatures which were 900°C and 950°C. The effect of carbon dispersion layers were observed and the results indicated that the increasing value of the average dispersion layer from 1.30 mm to 2.74 mm thickness was found to be related to increment of carburizing holding temperature . The increment of carbon thickness layer also resulted in improvement of hardness and tensile strength of carburized stainless steel.

  4. Mechanical Properties of Polyhydroxyalkanoate Bioceramic Nanocomposites

    Institute of Scientific and Technical Information of China (English)

    江涛; 胡平; 柳林; 李亚栋

    2002-01-01

    New composites prepared containing nanoscale hydroxyapatite or monetite uniformly distributed in a polyhydroxyalkanoate (polyhydroxybutyrate or polyhydroxybutyrate-hydroxyvalerate) matrix with mass fractions of 1%5% were then injected into dumb-like specimens. The results show that the tensile strength and the tensile modulus of the composites are improved. The microstructures of the composites were observed using transmission electron microscopy (TEM).

  5. Influence of Electric Field on Mechanical Properties of Al-Li Alloy Containing Cerium and Electronic Mechanism

    Institute of Scientific and Technical Information of China (English)

    刘兵; 陈铮; 王永欣; 王西宁

    2001-01-01

    The effect of electric field on the mechanical properties and microstructure of Al-Li alloy containing Ce was investigated, and mechanism was discussed. The experimental results show that the ductility of the alloy is enhanced by the electric field. The fracture features are changed and the precipitates are dispersed under the effect of the electric field. The mechanism discussion reveals that the effects of the electric field on the alloy are due to the change of the electron density in the alloy.

  6. Compressive and tensile mechanical properties of the porcine nasal septum

    OpenAIRE

    Al Dayeh, Ayman A.; HERRING, SUSAN W.

    2013-01-01

    The expanding nasal septal cartilage is believed to create a force that powers midfacial growth. In addition, the nasal septum is postulated to act as a mechanical strut that prevents the structural collapse of the face under masticatory loads. Both roles imply that the septum is subject to complex biomechanical loads during growth and mastication. The purpose of this study was to measure the mechanical properties of the nasal septum to determine (1) whether the cartilage is mechanically capa...

  7. 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.

  8. Mechanical properties of cellulose in orthopaedic devices and related environments.

    Science.gov (United States)

    Poustis, J; Baquey, C; Chauveaux, D

    1994-01-01

    The authors have undertaken a series of mechanical tests in order to assess the performance of regenerated cellulose under either static or dynamic conditions, and to evaluate its long-term behaviour under mechanical stress. In this respect, bending stiffness, resistance to compression, creep under compressive stress, in vitro and in vivo ageing and fatigue resistance were studied. It appears that this material demonstrates mechanical properties which depend upon its density, which is itself related to its water content. Moreover, this material is very stable under dynamic stress. This could be an interesting property for use in orthopaedic devices.

  9. Effect of vitro preservation on mechanical properties of brain tissue

    Science.gov (United States)

    Zhang, Wei; Liu, Yi-fan; Liu, Li-fu; Niu, Ying; Ma, Jian-li; Wu, Cheng-wei

    2017-05-01

    To develop the protective devices for preventing traumatic brain injuries, it requires the accurate characterization of the mechanical properties of brain tissue. For this, it necessary to elucidate the effect of vitro preservation on the mechanical performance of brain tissue as usually the measurements are carried out in vitro. In this paper, the thermal behavior of brain tissue preserved for various period of time was first investigated and the mechanical properties were also measured. Both reveals the deterioration with prolonged preservation duration. The observations of brain tissue slices indicates the brain tissue experiences karyorrhexis and karyorrhexis in sequence, which accounts for the deterioration phenomena.

  10. Process depending morphology and resulting physical properties of TPU

    Energy Technology Data Exchange (ETDEWEB)

    Frick, Achim, E-mail: achim.frick@hs-aalen.de; Spadaro, Marcel, E-mail: marcel.spadaro@hs-aalen.de [Institute of Polymer Science and Processing (iPSP), Aalen University (Germany)

    2015-12-17

    Thermoplastic polyurethane (TPU) is a rubber like material with outstanding properties, e.g. for seal applications. TPU basically provides high strength, low frictional behavior and excellent wear resistance. Though, due to segmented structure of TPU, which is composed of hard segments (HSs) and soft segments (SSs), physical properties depend strongly on the morphological arrangement of the phase separated HSs at a certain ratio of HSs to SSs. It is obvious that the TPU deforms differently depending on its bulk morphology. Basically, the morphology can either consist of HSs segregated into small domains, which are well dispersed in the SS matrix or of few strongly phase separated large size HS domains embedded in the SS matrix. The morphology development is hardly ruled by the melt processing conditions of the TPU. Depending on the morphology, TPU provides quite different physical properties with respect to strength, deformation behavior, thermal stability, creep resistance and tribological performance. The paper deals with the influence of important melt processing parameters, such as temperature, pressure and shear conditions, on the resulting physical properties tested by tensile and relaxation experiments. Furthermore the morphology is studied employing differential scanning calorimeter (DSC), transmission light microscopy (TLM), scanning electron beam microscopy (SEM) and transmission electron beam microscopy (TEM) investigations. Correlations between processing conditions and resulting TPU material properties are elaborated. Flow and shear simulations contribute to the understanding of thermal and flow induced morphology development.

  11. Latest Results On Jet Production and Properties from the LHC

    CERN Document Server

    Jones, G

    2012-01-01

    Investigations of jets performed by the ATLAS and CMS collaborations using collisions at $\\sqrt{s}$ = 7 TeV are described. To pics of interest are jet performance, production and the precision measurement of their properties. Comparison of the results to theoretical predictions are discussed and areas with poor agreement identified.

  12. Recent SELEX Results on the Properties of Charmed Hadrons

    Science.gov (United States)

    Engelfried, Jürgen

    2005-04-01

    The SELEX Fixed Target Experiment (Fermilab E781) employs beams of Σ-, pions and protons to study the production and decay properties of charmed Mesons and Baryons. Here we present recent results on doubly-charmed baryons and charmed-strange mesons.

  13. Restorative resins: abrasion vs. mechanical properties.

    Science.gov (United States)

    Jørgensen, K D

    1980-12-01

    The purpose of the present work was to examine whether it is possible by simple and reliable laboratory tests to evaluate the abrasion by food of Class 1 restorative resins. The results point to the following main conclusions: for the smooth-surface resins, i.e. the micro-filled composite and the unfilled resins, the Wallace hardness test appears to be a valid parameter for abrasion; the greater the depth of penetration of the Vickers diamond of this apparatus, the more severe abrasion is to be expected. The mode of abrasion in this type of resin is scratching. Porosity in the resins strongly enhances the abrasion. For the rough-surface resins, i.e. the conventional composites, a dual effect of the filler particles was concluded. The filler particles on the one hand protect the matrix against abrasion, but cause, on the other hand, in time an increase of the surface roughness of the composite and thereby via increased friction an increase of the abrasion. Considerations on possible ways to improve the present-day restorative resins are presented. It is stressed that the results obtained refer only to abrasion of Class 1 fillings by food.

  14. The coupled effects of geometry and surface orientation on the mechanical properties of metal nanowires

    Energy Technology Data Exchange (ETDEWEB)

    Ji Changjiang; Park, Harold S [Department of Civil and Environmental Engineering, Vanderbilt University, Nashville, TN 37235 (United States)

    2007-08-01

    We have performed atomistic simulations of the tensile loading of <100> and <110> copper nanowires to investigate the coupled effects of geometry and surface orientation on their mechanical behaviour and properties. By varying the nanowire cross section from square to rectangular, nanowires with dominant surface facets are created that exhibit distinct mechanical properties due to the different inelastic deformation mechanisms that are activated. In particular, we find that non-square nanowires generally exhibit lower yield stresses and strains, lower toughness, elevated fracture strains, and a propensity to deform via twinning; we quantify the links between the observed deformation mechanisms due to non-square cross section and the resulting mechanical properties, while illustrating that geometry can be utilized to tailor the mechanical properties of nanowires.

  15. Mechanical and water soaking properties of medium density fiberboard with wood fiber and soybean protein adhesive.

    Science.gov (United States)

    Li, Xin; Li, Yonghui; Zhong, Zhikai; Wang, Donghai; Ratto, Jo A; Sheng, Kuichuan; Sun, Xiuzhi Susan

    2009-07-01

    Soybean protein is a renewable and abundant material that offers an alternative to formaldehyde-based resins. In this study, soybean protein was modified with sodium dodecyl sulfate (SDS) as an adhesive for wood fiber medium density fiberboard (MDF) preparation. Second-order response surface regression models were used to study the effects and interactions of initial moisture content (IMC) of coated wood fiber, press time (PT) and temperature on mechanical and water soaking properties of MDF. Results showed that IMC of coated fiber was the dominant influencing factor. Mechanical and soaking properties improved as IMC increased and reached their highest point at an IMC of 35%. Press time and temperature also had a significant effect on mechanical and water soaking properties of MDF. Second-order regression results showed that there were strong relationships between mechanical and soaking properties of MDF and processing parameters. Properties of MDF made using soybean protein adhesive are similar to those of commercial board.

  16. Mechanical properties of branched actin filaments

    CERN Document Server

    Razbin, Mohammadhosein; Benetatos, Panayotis; Zippelius, Annette

    2015-01-01

    Cells moving on a two dimensional substrate generate motion by polymerizing actin filament networks inside a flat membrane protrusion. New filaments are generated by branching off existing ones, giving rise to branched network structures. We investigate the force-extension relation of branched filaments, grafted on an elastic structure at one end and pushing with the free ends against the leading edge cell membrane. Single filaments are modeled as worm-like chains, whose thermal bending fluctuations are restricted by the leading edge cell membrane, resulting in an effective force. Branching can increase the stiffness considerably; however the effect depends on branch point position and filament orientation, being most pronounced for intermediate tilt angles and intermediate branch point positions. We describe filament networks without cross-linkers to focus on the effect of branching. We use randomly positioned branch points, as generated in the process of treadmilling, and orientation distributions as measur...

  17. Mechanical Properties and Microstructure Investigation of Lead Free Solder

    Science.gov (United States)

    Wang, Qing; Gail, William F.; Johnson, R. Wayne; Strickland, Mark; Blanche, Jim

    2005-01-01

    While the electronics industry appears to be focusing on Sn-Ag-Cu as the alloy of choice for lead free electronics assembly, ,the exact composition varies by geographic region, supplier and user. Add to that dissolved copper and silver from the printed circuit board traces and surface finish, and there can be significant variation in the final solder joint composition. A systematic study of the mechanical and microstructural properties of Sn-Ag-Cu alloys with Ag varying from 2wt% to 4wt% and Cu varying from 0.5wt% to lSwt%, was undertaken in this research study. Different sample preparation techniques (water quenched, oil quenched and water quenched followed by reflow) were explored and the resulting microstructure compared to that of a typical reflowed lead free chip scale package (CSP) solder joint. Tensile properties (modulus, 0.2% yield strength and the ultimate tensile strength) and creep behavior of selected alloy compositions (Sn-4Ag-1 X u , Sn-4Ag-OSCu, Sn- 2Ag-1 X u , Sn-2Ag-OSCu, Sn-3.5Ag-O.SCu) were determined for three conditions: as- cast; aged for 100 hours at 125OC; and aged for 250 hours at 125OC. There was no significant difference in Young's Modulus as a function of alloy composition. After an initial decrease in modulus after 100 hours at 125"C, there was an insignificant change with further aging. The distribution of 0.2% strain yield stress and ultimate tensile strength as a function of alloy composition was more significant and decreased with aging time and temperature. The microstructures of these alloys were examined using light and scanning electron microscopy (LM and SEM) respectively and SEM based energy dispersive x-ray spectroscopy (EDS). Fracture surface and cross-section analysis were performed on the specimens after creep testing. The creep testing results and the effect of high temperature aging on mechanical properties is presented for the oil quenched samples. In general the microstructure of oil quenched specimen exhibited a

  18. Thermo-mechanical properties of SOFC components investigated by a combined method

    DEFF Research Database (Denmark)

    Teocoli, Francesca; Esposito, Vincenzo; Ramousse, Severine

    , and differential thermo-mechanical behavior at each layer. The combination of such factors can have a critical effect on the final shape and microstructure, and on the mechanical integrity. Thermo-mechanical properties and sintering mechanisms of important SOFC materials (CGO, YSZ, ScYSZ) were systematically...... characterized by mean of the combined use of optical dilatometry, cyclic loading thermo-mechanical analysis and scanning electron microscopy. The results from the different techniques were found complementary and the thorough understanding of viscoelastic properties of individual layers led to optimization...

  19. Mechanical properties of ceramic composite tubes

    Energy Technology Data Exchange (ETDEWEB)

    Curtin, W.A.; Oleksuk, L.L.; Reifsnider, K.L. [Virginia Polytechnic Inst. and State Univ., Blacksburg, VA (United States); Stinton, D.P. [Oak Ridge National Lab., TN (United States)

    1995-08-01

    Results of axial tension tests on SiC/SiC tubular ceramic composite components fabricated by a forced-M technique are presented. Axial elastic modulus measurements on a number of tubes show that the Young`s modulus varies along the length of the tube, with occasional very stiff or very soft regions. Tests to failure on a few tubes show the initiation of non-linear stress-strain behavior to be in the range of 3-9 ksi, followed by extensive non-linear deformation up to failure. For one tube, the failure stress obtained was 20.1 ksi, but the strains to failure at various axial locations varies from 0.19%to 0.24%. The correlation between modulus and proportional limit is considered within the ACK matrix cracking theory and within a model in which matrix cracking between fiber tows occurs, both modified to account for matrix porosity. The crack size required to cause stress concentrations large enough to cause failure at the observed strength is considered. Predictions for both matrix cracking and strength suggest that the current generation of tubes are controlled by microstructural defects.

  20. Hollow silica spheres: synthesis and mechanical properties.

    Science.gov (United States)

    Zhang, Lijuan; D'Acunzi, Maria; Kappl, Michael; Auernhammer, Günter K; Vollmer, Doris; van Kats, Carlos M; van Blaaderen, Alfons

    2009-03-03

    Core-shell polystyrene-silica spheres with diameters of 800 nm and 1.9 microm were synthesized by soap-free emulsion and dispersion polymerization of the polystyrene core, respectively. The polystyrene spheres were used as templates for the synthesis of silica shells of tunable thickness employing the Stöber method [Graf et al. Langmuir 2003, 19, 6693]. The polystyrene template was removed by thermal decomposition at 500 degrees C, resulting in smooth silica shells of well-defined thickness (15-70 nm). The elastic response of these hollow spheres was probed by atomic force microscopy (AFM). A point load was applied to the particle surface through a sharp AFM tip, and successively increased until the shell broke. In agreement with the predictions of shell theory, for small deformations the deformation increased linearly with applied force. The Young's modulus (18 +/- 6 GPa) was about 4 times smaller than that of fused silica [Adachi and Sakka J. Mater. Sci. 1990, 25, 4732] but identical to that of bulk silica spheres (800 nm) synthesized by the Stöber method, indicating that it yields silica of lower density. The minimum force needed to irreversibly deform (buckle) the shell increased quadratically with shell thickness.

  1. Mechanisms Responsible for Microwave Properties in High Performance Dielectric Materials

    Science.gov (United States)

    Zhang, Shengke

    Microwave properties of low-loss commercial dielectric materials are optimized by adding transition-metal dopants or alloying agents (i.e. Ni, Co, Mn) to tune the temperature coefficient of resonant frequency (tau f) to zero. This occurs as a result of the temperature dependence of dielectric constant offsetting the thermal expansion. At cryogenic temperatures, the microwave loss in these dielectric materials is dominated by electron paramagnetic resonance (EPR) loss, which results from the spin-excitations of d-shell electron spins in exchange-coupled clusters. We show that the origin of the observed magnetically-induced shifts in the dielectric resonator frequency originates from the same mechanism, as described by the Kramers-Kronig relations. The temperature coefficient of resonator frequency, tauf, is related to three material parameters according to the equation, tau f = - (½ tauepsilon + ½ taumu + alphaL), where tauepsilon, taumu , and alphaL are the temperature coefficient of dielectric constant, magnetic permeability, and lattice constant, respectively. Each of these parameters for dielectric materials of interest are measured experimentally. These results, in combination with density functional simulations, developed a much improved understanding of the fundamental mechanisms responsible for tau f. The same experimental methods have been used to characterize in-situ the physical nature and concentration of performance-degrading point defects in the dielectrics of superconducting planar microwave resonators.

  2. Mechanical properties and structure of magnesium alloy AS31

    Directory of Open Access Journals (Sweden)

    A. Hanus

    2008-07-01

    Full Text Available Contemporary materials should possess high mechanical properties, physical and chemical, as well as technological ones, to ensure long and reliable use. The non-ferrous metals alloys used nowadays, including the magnesium alloys, meet the above-mentioned requirements and expectations regarding the contemporary materials.Magnesium alloys are primarily used in aeronautical and automobile industry in wide variety of structural characteristics because of their favorable combination of tensile strength (160 to 365 MPa, elastic modulus (45 GPa, and low density (1 740 kg/m3, which is two-thirds that of aluminum. Magnesium alloys have high strength-to-weight ratio (tensile strength/density, comparable to those of other structural metals. [1-6]Knowledge of the relaxation properties of metal materials at high temperatures is necessary for the verification of susceptibility of castings to the creation of defects during the production process. Temperature limits of materials where highest tension values are generated may be detected with tensile tests under high temperatures. The generated tensions in the casting are a cause of the creation and development of defects. At acoustic emission (hereinafter called the "AE" use, tensile tests at high temperatures may, among other things, be used for analysis of the AE signal sources and set, in more detail, the temperature limit of elastic-plastic deformations existence in the material under examination. The results of the temperature drop where tension at casting cooling is generated or its release at heating are basic data for controlled cooling mode (and temperature of casting knocking out of the form as well as necessary for the thermal mode for the casting tension reduction. [7-9]Knowledge of elastic-plastic properties at elevated temperatures is often important for complex evaluation of magnesium alloys. Objective of the work was focused on determination of changes of elastic-plastic properties of magnesium

  3. The effect of long term exposition at 540 °C on the empirical correlations for determination of mechanical properties of low alloy CrMoV steel from the results of Small Punch tests

    Directory of Open Access Journals (Sweden)

    Ondřej Dorazil

    2016-03-01

    Full Text Available The present paper describes the effect of long term exposure at 540 °C on the empirical correlations for determination of yield strength, tensile strength and FATT of 14MoV6-3 low alloy steel. Empirical correlations obtained for the pipe in as received state were compared with the results of standardized tensile, impact and Small Punch tests carried out on the testing materials cut of the three pipes of significantly different metallurgical quality and time of exposure at 540 °C.

  4. 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.

  5. Mechanical properties of materials at micro/nano scales

    Science.gov (United States)

    Xu, Wei-Hua

    Mechanical properties of materials in small dimensions, including the depth-dependent hardness at the nano/micrometer scales, and the mechanical characterization of thin films and nanotubes, are reported. The surface effect on the depth-dependent nano/microhardness was studied and an apparent surface stress was introduced to represent the energy dissipated per unit area of a solid surface. A plastic bearing ratio model was proposed for the nanoindentation of rough surfaces. The energy dissipation occurring at the indented surface is among the factors that cause the Indentation Size Effect (ISE) at the micro/nanometer scales. Furthermore, an elastic-plastic bearing ratio model was developed for nanoindentation of rough surfaces with a flat indenter tip. The theoretical predictions agree with the experimental results and finite element simulations, from which the elastic constant and the surface hardness were extracted. The surface hardness exhibits an inverse ISE due to the interaction of asperities. The nanoindentation tests on Highly Oriented Pyrolytic Graphite (HOPG) may lead to the formation of carbon tubes, which are rolled up by the delaminated graphite layers. The nanoindentation loading-unloading curves reveal single pop-in and multiple pop-in phenomena, which is induced by fracture of the graphite layers and/or by delamination between the layers. From the load at pop-in, the fracture strength of the layers and/or the bonding strength between the layers can be estimated by the elastic field model for Hertzian contact including sliding friction for transverse isotropy. Two novel methods were developed to estimate the mechanical properties of films, including the Raman spectra method for the estimation of residual stresses in thin ferroelectric films and the microbridge testing method for the mechanical characterization of trilayer thin films. Mechanical characterization was also carried out on Tobacco Mosaic Virus (TMV) nanotubes with each being comprised of

  6. Mechanical properties of transgenic silkworm silk at high rate impact

    Science.gov (United States)

    Chu, Jou-Mei

    Transgenic silkworm silk was created to obtain the quality of spider silk while being mass-producible. Due to the variability in sequencing between the silkworm and spider DNA, the resulting transgenic silkworm silk may have different properties compared to spider silk. Furthermore, the high strain rate mechanical response of this new natural fiber is still unknown and needs to be characterized. In this experimental research, a quasi-static load frame (MTS) and a Kolsky tension bar are used to characterize the tensile stress-strain response of transgenic silkworm silk over a range of strain-rates between 10-3/s to 103/s. The results show that transgenic silkworm silk tends to have high overall elongation and initial stiffness at high strain rates compared to those of spider silk. Furthermore, specimen gage length sensitivity is studied with gage lengths of 3.97 mm (5/32 in), 4.76 mm (3/16 in), and 6.35 mm (1/4 in). Fracture surfaces are examined via Scanning Electron Microscopy (SEM) and reveal that the fracture mode is similar to that of spider silk. Therefore, it may be possible for the tensile properties of transgenic silkworm silk be comparable to that of spider silk.

  7. Mechanical properties and network structure of wheat gluten foams.

    Science.gov (United States)

    Blomfeldt, Thomas O J; Kuktaite, Ramune; Johansson, Eva; Hedenqvist, Mikael S

    2011-05-09

    This Article reports the influence of the protein network structure on the mechanical properties of foams produced from commercial wheat gluten using freeze-drying. Foams were produced from alkaline aqueous solutions at various gluten concentrations with or without glycerol, modified with bacterial cellulose nanosized fibers, or both. The results showed that 20 wt % glycerol was sufficient for plasticization, yielding foams with low modulus and high strain recovery. It was found that when fibers were mixed into the foams, a small but insignificant increase in elastic modulus was achieved, and the foam structure became more homogeneous. SEM indicated that the compatibility between the fibers and the matrix was good, with fibers acting as bridges in the cell walls. IR spectroscopy and SE-HPLC revealed a relatively low degree of aggregation, which was highest in the presence of glycerol. Confocal laser scanning microscopy revealed distinct differences in HMW-glutenin subunits and gliadin distributions for all of the different samples.

  8. Development and mechanical properties of structural materials from lunar simulants

    Science.gov (United States)

    Desai, Chandra S.; Girdner, K.; Saadatmanesh, H.; Allen, T.

    1991-01-01

    Development of the technologies for manufacture of structural and construction materials on the Moon, utilizing local lunar soil (regolith), without the use of water, is an important element for habitats and explorations in space. Here, it is vital that the mechanical behavior such as strength and flexural properties, fracture toughness, ductility and deformation characteristics be defined toward establishment of the ranges of engineering applications of the materials developed. The objective is to describe the research results in two areas for the above goal: (1) liquefaction of lunar simulant (at about 100 C) with different additives (fibers, powders, etc.); and (2) development and use of a new triaxial test device in which lunar simulants are first compressed under cycles of loading, and then tested with different vacuums and initial confining or in situ stress.

  9. Mechanical properties of steel rope wires -– quality test assurance

    Directory of Open Access Journals (Sweden)

    Jaroslava Dečmanová

    2010-02-01

    Full Text Available We investigate the mechanical properties of wires of steel ropes by tests in accordance with rule in operation and valid regulation.There are specified values of minimal and maximum capacity or strenghts and values of minimal bendings and torsion in them. Minimalvalues of bendings and torsion are rated wire strenght, diameter and surface treatment dependent. It is suitable to use the calculationof irregularity coefficient of steel wires strenght for quality assessment of steel ropes which put into practice soviet authors Žitkovand Pospechov. Statistical methods make possible to review the quality of steel ropes from the test results of their wires on capacity,bending and torsion. In the paper we evaluate and compare the quality of two steel ropes with triangular strands, we appear fromprotocols about their tests in the accredited testing station of steel ropes of our workstation.

  10. Mechanical and physical properties of irradiated type 348 stainless steel

    Energy Technology Data Exchange (ETDEWEB)

    Beeston, J.M.

    1980-01-01

    A type 348 stainless steel in-pile tube irradiated to a fluence of 3 x 10/sup 22/ n/cm/sup 2/, E > 1 MeV (57 dpa), was destructively examined. The service had resulted in a maximum total creep of 1.8% at the high fluence. The metal temperature ranged between 623 and 652/sup 0/K, hence the thermal creep portion of the total was negligible. Total creep was greater than had been anticipated from creep data for austenitic stainless steels irradiated in other reactors. The objectives of the destructive examination were to determine the service-induced changes of mechanical and physical properties, and to assess the possibility of adverse effects of both these changes and the greater total creep on the prospective service life of other tubes.

  11. Optical and mechanical properties of hot-pressed cesium iodide

    Energy Technology Data Exchange (ETDEWEB)

    Kim, H.E.; Moorhead, A.J. (Oak Ridge National Lab., TN (USA). Metals and Ceramics Div.)

    1990-03-01

    This paper reports on polycrystalline CsI disks fabricated by hot-pressing in a nitrogen-purged glove box. Densification during hot-pressing occurred by plastic flow resulting from lattice dislocation glide. Primary recrystallization and extensive grain growth were observed. Both the optical and mechanical properties of this material were significantly affected by grain growth, but in opposite ways. Transmittance increased and strength decreased as grain size increased. The hot-pressed CsI had transmittance of about 85% in the extra-long-wavelength infrared range, a value equivalent to that of single-crystal CsI. The flexural strengths of the CsI that was hot-pressed under conditions that minimized grain growth was about 8 times higher than that of single-crytal CsI.

  12. Electrical and Mechanical Properties of PMMA/nano-ATO Composites

    Institute of Scientific and Technical Information of China (English)

    Wei Pan; Huiqin Zhang; Yan Chen

    2009-01-01

    Conducting nanocomposites of poly (methyl methacryiate) (PMMA) and antimony doped tin oxide (ATO)were prepared by solution blending. The influences of ATO content on the electrical conductivity, thermal stability, and mechanical properties of the nanocomposites were investigated. A homogeneous dispersion of silane coupling agent modified ATO was achieved in PMMA matrix as evidenced by scanning electron microscopy. The resultant PMMA/silane-ATO nanocomposites were electrically conductive with significant conductivity enhancement at 4 wt pct. It was found that the composition at 4 wt pct ATO gave the higher tensile strength. Furthermore, it gave the largest elongation at break value among all the compositions.Thermal stability of the nanocornposites was remarkably enhanced by the incorporation of silane-ATO.

  13. Regional multiaxial mechanical properties of the porcine anterior lens capsule.

    Science.gov (United States)

    David, G; Pedrigi, R M; Heistand, M R; Humphrey, J D

    2007-02-01

    The lens capsule of the eye plays fundamental biomechanical roles in both normal physiological processes and clinical interventions. There has been modest attention given to the mechanical properties of this important membrane, however, and prior studies have focused on 1-D analyses of the data. We present results that suggest that the porcine anterior lens capsule has a complex, regionally dependent, nonlinear, anisotropic behavior. Specifically, using a subdomain inverse finite element method to analyze data collected via a new biplane video-based test system, we found that the lens capsule is nearly isotropic (in-plane) near the pole but progressively stiffer in the circumferential compared to the meridional direction as one approaches the equator. Because the porcine capsule is a good model of the young human capsule, there is strong motivation to determine if similar regional variations exist in the human lens capsule for knowledge of such complexities may allow us to improve the design of surgical procedures and implants.

  14. Hyperhoneycomb boron nitride with anisotropic mechanical, electronic, and optical properties

    Science.gov (United States)

    Yu, Jin; Qu, Lihua; van Veen, Edo; Katsnelson, Mikhail I.; Yuan, Shengjun

    2017-09-01

    Boron nitride structures have excellent thermal and chemical stabilities. Based on state-of-art theoretical calculations, we propose a wide-gap semiconducting BN crystal with a three-dimensional hyperhoneycomb structure (Hp-BN), which is both mechanically and thermodynamically stable. Our calculated results show that Hp-BN has a higher bulk modulus and a smaller energy gap as compared to c-BN. Moreover, due to the unique bonding structure, Hp-BN exhibits anisotropic electronic and optical properties. It has great adsorption in the ultraviolet region, but it is highly transparent in the visible and infrared region, suggesting that the Hp-BN crystal could have potential applications in electronic and optical devices.

  15. Mechanical properties of gutta-percha sulfide modified asphalt

    Science.gov (United States)

    Zou, X. Y.; Gu, X. Y.; Wang, X. W.

    2017-01-01

    Gutta-percha is the isomer of caoutchouc and can be used to enhance the performance of asphalt. In this paper, the produce proceedings of gutta-percha sulfide and gutta-percha sulfide modified asphalt are introduced. The performance indices of gutta-percha sulfide modified asphalt samples with different proportions are examined based on laboratory tests and the optimum ratio of gutta-percha and sulfur is decided.The micromechanism, temperature sensitivity, high and low temperature properties and viscoelasticity of the polymer modified asphalt are analyzed to discuss the modified mechanism and to decide the optimal polymer content. Low temperature bending tests are carried out to verify the low temperature performance of gutta-percha sulfide modified asphalt mixture. Research results showed that gutta-percha sulfide modified asphalt has good low temperature performance and a promising application prospect in the cold regions.

  16. Surface effects on the mechanical properties of nanoporous materials

    Energy Technology Data Exchange (ETDEWEB)

    Xia Re [School of Power and Mechanical Engineering, Wuhan University, Wuhan 430072 (China); Li Xide; Feng Xiqiao [AML, Department of Engineering Mechanics, Tsinghua University, Beijing 100084 (China); Qin Qinghua [School of Engineering, Australian National University, Canberra, ACT 0200 (Australia); Liu Jianlin, E-mail: fengxq@tsinghua.edu.cn [Department of Engineering Mechanics, China University of Petroleum, Qingdao 266555 (China)

    2011-07-01

    Using the theory of surface elasticity, we investigate the mechanical properties of nanoporous materials. The classical theory of porous materials is modified to account for surface effects, which become increasingly important as the characteristic sizes of microstructures shrink to nanometers. First, a refined Timoshenko beam model is presented to predict the effective elastic modulus of nanoporous materials. Then the surface effects on the elastic microstructural buckling behavior of nanoporous materials are examined. In particular, nanoporous gold is taken as an example to illustrate the application of the proposed model. The results reveal that both the elastic modulus and the critical buckling behavior of nanoporous materials exhibit a distinct dependence on the characteristic sizes of microstructures, e.g. the average ligament width.

  17. Polyimide foam-like microstructures: technology and mechanical properties

    Science.gov (United States)

    Dobrzynska, J. A.; Joris, P.; Jiguet, S.; Renaud, P.; Gijs, M. A. M.

    2011-10-01

    We report a process for the realization of polyimide films with custom-designed microporosity based on the heat-induced depolymerization of polyimide-embedded polypropylene carbonate microstructures. The foam-like microstructures are up to 40 µm thick and incorporate air cavities with a width ranging from 20 to 200 µm, a length up to 5 mm and a height of 20 µm. We model the mechanical stress-strain properties of the microcavities using both analytical and numerical methods. The simulation data are in good agreement with the results of nanoindentation and microcompression experiments, which show the reduction of the effective Young's modulus from 5.77 ± 0.06 GPa for bulk polyimide to 2.51 ± 0.03 GPa for a foam-like layer.

  18. Angularly Deformed Special Relativity and its Results for Quantum Mechanics

    CERN Document Server

    Glinka, Lukasz Andrzej

    2015-01-01

    In this paper, the deformed Special Relativity, which leads to an essentially new theoretical context of quantum mechanics, is presented. The formulation of the theory arises from a straightforward analogy with the Special Relativity, but its foundations are laid through the hypothesis on breakdown of the velocity-momentum parallelism which affects onto the Einstein equivalence principle between mass and energy of a relativistic particle. Furthermore, the derivation is based on the technique of an eikonal equation whose well-confirmed physical role lays the foundations of both optics and quantum mechanics. As a result, we receive the angular deformation of Special Relativity which clearly depicts the new deformation-based theoretical foundations of physics, and, moreover, offers both constructive and consistent phenomenological discussion of the theoretical issues such like imaginary mass and formal superluminal motion predicted in Special Relativity for this case. In the context of the relativistic theory, p...

  19. Physical and Mechanical Properties of Sorghum Grains (Sorghum Vulgare

    Directory of Open Access Journals (Sweden)

    2016-11-01

    Full Text Available The physical and mechanical properties of sorghum grains (sorghum vulgare were studied at varying moisture contents of 13%, 20% and 30% (w.b. The four varieties of sorghum grains studied include; Dura, Guinea, Faterita and Kafir. Results indicate that the size ranges were 3.94mm - 4.83mm for Dura variety; 3.75mm - 4.54mm for Guinea variety; 3.21mm - 4.42mm for Kafir variety and 2.70mm - 4.14mm for Faterita variety. Irregularities in the shapes of the grains were observed but all approximated to a sphere. In the mechanical properties, at major diameter, Dura variety had highest rupture force of 1.16kN at 13% moisture content (w.b while the Guinea variety had the lowest rupture force of 0.955kN. In minor diameter, the Dura variety also recorded highest rupture force of 1.12kN at 13% moisture content (w.b while the Kafir variety had the lowest value of 0.952kN. Also at 20% moisture content, the Dura variety had highest rupture force of 1.025kN while the Guinea variety had the lowest rupture force of 0.965kN. The same trend applies in the varieties at 30% moisture content. This is because, increase in moisture content results to decrease in rupture force. And this implies that force beyond these points at these moisture contents may cause damage to the sorghum varieties.

  20. Estimates of Identification Result Disturbances in Parallel Mechanism Calibration

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    General QR decomposition of the observation matrix is used to solve identification functions to evaluate identification results of every parameter in parallel mechanism calibrations. A relationship between measured information and identification results is obtained by analyzing numerous matrix transforms and QR decompositions. When distributions of measurement error are determined, random distributions of identification result disturbances (IRDs) can be obtained from this relationship as a function of measurement errors. Then the ranges of the IRDs can be effectively estimated, even if true parameter values are unknown. An optimization index based on IRD estimate is presented to select measurement configurations to achieve smaller IRDs. Two simulation examples were carried out with different modes and calibration methods. The results show that the method is effective and that the optimization index is useful. Some regular parameter identification problems can be explained by the IRD estimates.

  1. 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.

  2. [Classification and several mechanical properties of core composite resins].

    Science.gov (United States)

    Yamada, T; Hosoda, H; Tsurugai, T

    1990-03-01

    According to the classification proposed by Hosoda, six core resins could be divided into two categories on the basis of the elemental composition and size distribution of filler particles by SEM observation and EDX analysis. Furthermore, several mechanical properties of the resins were determined. The following facts were found: Bell Feel Core, Clearfil Core, Clearfil PhotoCore, Core Max, and Core Max II resins were classified as a semihybrid resin, and Microrest Core resin as a hybrid type resin. The elements detected in the resins by the EDX were Si, Zr, Al, Ba and La. The mechanical properties of the resins were shown to be highly stable at one day or one week after curing. The mechanical properties of the resins suggest that the subsequent crown preparation and impression taking should be postponed until the next appointment.

  3. Mechanical Properties Of Calcium Carbonate Crystallization Of Chitin Reinforced Polymer

    Directory of Open Access Journals (Sweden)

    Michael Ikpi Ofem

    2015-08-01

    Full Text Available ABSTRACT Chitin whiskers and CaCO3 were reinforced with Polyacrylic acid. Mechanical and thermal properties were characterised. The effect of CaCO3 growth on the mechanical properties of chitin whiskers reinforced Polyacrylic acid indicated that better mechanical properties can be achieved at chitin content of 3 wt when compared with neat PAA. The growth of CaCO3 on CHWPAA composite increased the melting endotherm of CHWPAACaCO3 composite when compared with CHWPAA composite. As an indication of increase in thermal stability the final weight loss at the end of decomposition for all composites was between 20 and 37 far below the 78 for the CHWPAA composite and 84 for the pure PAA .

  4. 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.

  5. Investigation of mechanical properties of pavement through electromagnetic techniques

    Science.gov (United States)

    Benedetto, Andrea; Tosti, Fabio; D'Amico, Fabrizio

    2014-05-01

    Ground-penetrating radar (GPR) is considered as one of the most flexible geophysical tools that can be effectively and efficiently used in many different applications. In the field of pavement engineering, GPR can cover a wide range of uses, spanning from physical to geometrical inspections of pavements. Traditionally, such inferred information are integrated with mechanical measurements from other traditional (e.g. plate bearing test) or non-destructive (e.g. falling weight deflectometer) techniques, thereby resulting, respectively, in time-consuming and low-significant measurements, or in a high use of technological resources. In this regard, the new challenge of retrieving mechanical properties of road pavements and materials from electromagnetic measurements could represent a further step towards a greater saving of economic resources. As far as concerns unpaved and bound layers it is well-known that strength and deformation properties are mostly affected, respectively, by inter-particle friction and cohesion of soil particles and aggregates, and by bitumen adhesion, whose variability is expressed by the Young modulus of elasticity. In that respect, by assuming a relationship between electromagnetic response (e.g. signal amplitudes) and bulk density of materials, a reasonable correlation between mechanical and electric properties of substructure is therefore expected. In such framework, a pulse GPR system with ground-coupled antennae, 600 MHz and 1600 MHz centre frequencies was used over a 4-m×30-m test site composed by a flexible pavement structure. The horizontal sampling resolution amounted to 2.4×10-2 m. A square regular grid mesh of 836 nodes with a 0.40-m spacing between the GPR acquisition tracks was surveyed. Accordingly, a light falling weight deflectometer (LFWD) was used for measuring the elastic modulus of pavement at each node. The setup of such instrument consisted of a 10-kg falling mass and a 100-mm loading plate so that the influence domain

  6. Antioxidant Property of Jobelyn as the Possible Mechanism Underlying

    Directory of Open Access Journals (Sweden)

    Solomon Umukoro

    2013-01-01

    Full Text Available   Introduction: Amnesia or loss of memory is the cardinal hallmark of Alzheimer’s disease (AD, a progressive neurodegenerative disorder associated with ageing process. Although, AD had been discovered over a century ago, drugs which could cure or halt the progression of the disease are yet to see the light of the day. However, there has been a growing interest in the use of phytomedicines with multipronged mechanisms of action that could target various aspects of the pathologies of AD. Jobelyn (JB is a potent antioxidant African polyherbal formulation with active components that have been acclaimed to show neuroprotection. T his investigation was carried out to evaluate whether JB has anti-amnesic and antioxidant activities.   Methods: The alteration of alternation behavior in the Y-maze paradigm was utilized as the test for memory function in mice. The effect of JB on a cetylcholinesterase (AChE activity, malondialdehyde (MDA level and the concentrations of glutathione (GSH in the frontal cortex and hippocampus were assessed in rats as means of providing insight into the mechanism underlying its anti-amnesic activity. The animals were given JB (1, 2.5 or 5mg/kg, i.p. daily for 7 days before the biochemical assays or test for memory functions were carried out.   Results: JB was found to produce a significant increase in the level of alternation behavior compared with the control, suggesting anti-amnesic activity. Also, JB reversed the memory impairment induced by scopolamine, which further indicates anti-amnesic property. Furthermore, JB demonstrated a significant inhibition of MDA formation in the frontal cortex and hippocampus of rats, indicating antioxidant property. In addition, it increased the defense armory of the brain tissues, as it significantly increased the concentrations of GSH in the frontal cortex and hippocampus of rats. However, JB did not demonstrate any inhibitory effect against AChE activity in the frontal cortex and

  7. 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.

  8. Physical and mechanical properties of nanoreinforced particleboard composites

    OpenAIRE

    Candan,Zeki; AKBULUT, Turgay

    2015-01-01

    Novel composite materials having desired performance properties can be developed by nanotechnology. The major objective of this research was to produce nanomaterial- reinforced particleboard composites with enhanced physical and mechanical performance. Urea formaldehyde adhesive used to produce particleboard composites was reinforced with nanoSiO2, nanoAl2O3, and nanoZnO at loading level of 0%, 1%, and 3%. To evaluate physical properties density, thickness swelling, water absorption, and equi...

  9. Effect of Heat Treatment on Mechanical Property of High Cr-W Cast Iron

    Institute of Scientific and Technical Information of China (English)

    Liu Jianping; Li Lixia

    2007-01-01

    The microstructure of high Cr-W cast iron after heat treatment were analyzed, and the effect of various heat treatment temperature and time on mechanical properties of high Cr-W cast iron were studied, and the best process parameter of heat treatment was provided in this paper. The results show that the heat treatment can improve the mechanical property of high Cr-W cast iron, and higher synthetic mechanical property of high Cr-W cast iron can be obtained when treated with normalization at 980℃ for 2h and tempered at 400℃ for 2h.

  10. Research on Air-dried Density and Mechanical Properties of Moso Bamboo from Different Plantations

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    In order to further research bamboo cultivation and expand its application field, air-dried density and mechanical properties of Moso bamboo from the 2 plantations under the same site condition were measured and analyzed by using the national standard The Testing Methods for Physical and Mechanical Properties of Bamboo (GB / T 15780-1995). And the single linear regression analysis was carried out. The results showed that air-dried density and mechanical properties of the 2 kinds of Moso bamboo increase with...

  11. Mechanical properties of natural fibre reinforced polymer composites

    Indian Academy of Sciences (India)

    A S Singha; Vijay Kumar Thakur

    2008-10-01

    During the last few years, natural fibres have received much more attention than ever before from the research community all over the world. These natural fibres offer a number of advantages over traditional synthetic fibres. 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 Hibiscus sabdariffa fibre reinforced polymer composites such as tensile, compressive and wear properties were investigated as a function of fibre loading. Initially urea–formaldehyde resin prepared was subjected to evaluation of its optimum mechanical properties. Then reinforcing of the resin with Hibiscus sabdariffa fibre was accomplished in three different forms: particle size, short fibre and long fibre by employing optimized resin. Present work reveals that mechanical properties such as tensile strength, compressive strength and wear resistance etc of the urea–formaldehyde resin increases to considerable extent when reinforced with the fibre. Thermal (TGA/DTA/DTG) and morphological studies (SEM) of the resin and biocomposites have also been carried out.

  12. The relationships between deformation mechanisms and mechanical properties of additively manufactured porous biomaterials.

    Science.gov (United States)

    Kadkhodapour, J; Montazerian, H; Darabi, A Ch; Zargarian, A; Schmauder, S

    2016-09-16

    Modulating deformation mechanism through manipulating morphological parameters of scaffold internal pore architecture provides potential to tailor the overall mechanical properties under physiological loadings. Whereas cells sense local strains, cell differentiation is also impressed by the elastic deformations. In this paper, structure-property relations were developed for Ti6-Al-4V scaffolds designed based on triply periodic minimal surfaces. 10mm cubic scaffolds composed of 5×5×5 unit cells formed of F-RD (bending dominated) and I-WP (stretching dominated) architectures were additively manufactured at different volume fractions and subjected to compressive tests. The first stages of deformation for stretching dominated structure, was accompanied by bilateral layer-by-layer failure of unit cells owing to the buckling of micro-struts, while for bending dominated structure, namely F-RD, global shearing bands appeared since the shearing failure of struts in the internal architecture. Promoted mechanical properties were found for stretching dominated structure since the global orientation of struts were parallel to loading direction while inclination of struts diminished specific properties for bending dominated structure. Moreover, elastic-plastic deformation was computationally studied by applying Johnson-Cook damage model to the voxel-based models in FE analysis. Scaling analysis was performed for mechanical properties with respect to the relative density thereby failure mechanism was correlated to the constants of power law describing mechanical properties.

  13. IMPROVED PROCESSING FOR MICROSTRUCTURES AND MECHANICAL PROPERTIES OF A COMMERCIAL PIPELINE STEEL

    Institute of Scientific and Technical Information of China (English)

    Y.C. Wang; Y.S. Li; M.C. Zhao; K. Yang

    2005-01-01

    The transformation productions of hot-deformation simulation experiments were investigated us ing a Gleeble-1500 hot simulator for a commercial pipeline steel. Based on the investigation results, the improved thermo-mechanical control processing (TMCP) schedules containing a two stage multi-pass controlled rolling coupled with moderate cooling rates were applied to hot rolling experiments and acicular ferrite dominated microstructure was obtained. Microstructures and mechanical properties of hot rolled plates were related to TMCP processing, and regression equations describing the relation between processing parameters and mechanical properties in the current TMCP were developed, which could be used to predict mechanical properties of the experimental steel during commercially processing. It was found that with an increase in cooling rate after hot rolling, grain size in the microstructure became smaller, the amount of polyg onal ferrite decreased and acicular ferrite increased, and accordingly mechanical properties increased.

  14. 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.

  15. Structures and Mechanical Properties of PVC/Na+- Montmorillonite Nanocomposites

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    Poly (vinyl chloride)/Na+-montmorillonite (PVC/MMT) nanocomposites with different MMT contents were prepared via melt blending. Wide-angle X-ray diffraction (WAXD) and transmission electron microscopy (TEM) were used to characterize the structures. Effects of MMT content on the mechanical properties were also studied. It is found that PVC molecular chains can intercalate into the gallery of MMT layers during melt blending process, the stiffness and toughness of the composites are improved simultaneously within 0.5~7wt% MMT content, and the transparency and mechanical properties decrease as MMT content further increases.

  16. 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...

  17. 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.

  18. Mechanical properties and energy absorption characteristics of a polyurethane foam

    Energy Technology Data Exchange (ETDEWEB)

    Goods, S.H.; Neuschwanger, C.L.; Henderson, C.; Skala, D.M.

    1997-03-01

    Tension, compression and impact properties of a polyurethane encapsulant foam have been measured as a function of foam density. Significant differences in the behavior of the foam were observed depending on the mode of testing. Over the range of densities examined, both the modulus and the elastic collapse stress of the foam exhibited power-law dependencies with respect to density. The power-law relationship for the modulus was the same for both tension and compression testing and is explained in terms of the elastic compliance of the cellular structure of the foam using a simple geometric model. Euler buckling is used to rationalize the density dependence of the collapse stress. Neither tension nor compression testing yielded realistic measurements of energy absorption (toughness). In the former case, the energy absorption characteristics of the foam were severely limited due to the inherent lack of tensile ductility. In the latter case, the absence of a failure mechanism led to arbitrary measures of energy absorption that were not indicative of true material properties. Only impact testing revealed an intrinsic limitation in the toughness characteristics of the material with respect to foam density. The results suggest that dynamic testing should be used when assessing the shock mitigating qualities of a foam.

  19. A hybrid approach to simulating mechanical properties of polymer nanocomposites.

    Science.gov (United States)

    Mccarron, Andy P; Raj, Sharad; Hyers, Robert; Kim, Moon K

    2009-12-01

    Empirical studies indicate that a polymer reinforced with nanoscale particles could enhance its mechanical properties such as stiffness and toughness. To give insight into how and why this nanoparticle reinforcement is effective, it is necessary to develop computational models that can accurately simulate the effects of nanoparticles on the fracture characteristics of polymer composites. Furthermore, a hybrid model that can account for both continuum and non-continuum effects will hasten the development of not only new hierarchical composite materials but also new theories to explain their behavior. This paper presents a hybrid modeling scheme for simulating fracture of polymer nanocomposites by utilizing an atomistic modeling approach called Elastic Network Model (ENM) in conjunction with a traditional Finite Element Analysis (FEA). The novelty of this hybrid ENM-FEA approach lies in its ability to model less interesting outer domains with FEA while still accounting for areas of interest such as crack tip reion and the interface between a nanoparticle and the polymer matrix at atomic scale with ENM. Various simulation conditions have been tested to determine the feasibility of the proposed hybrid model. For instance, an iterative result from a uniaxial loading with isotropic properties in an ENM-FEA model shows accuracy and convergence to the analytic solution.

  20. Influence of the soil genesis on physical and mechanical properties.

    Science.gov (United States)

    Marschalko, Marian; Yilmaz, Işık; Fojtová, Lucie; Kubečka, Karel; Bouchal, Tomáš; Bednárik, Martin

    2013-01-01

    The paper deals with the influence of soil genesis on the physical-mechanical properties. The presented case study was conducted in the region of the Ostrava Basin where there is a varied genetic composition of the Quaternary geological structure on the underlying Neogeneous sediments which are sediments of analogous granulometry but different genesis. In this study, 7827 soil samples of an eolian, fluvial, glacial, and deluvial origin and their laboratory analyses results were used. The study identified different values in certain cases, mostly in coarser-grained foundation soils, such as sandy loam S4 (MS) and clayey sand F4 (CS). The soils of the fluvial origin manifest different values than other genetic types. Next, based on regression analyses, dependence was proved neither on the deposition depth (depth of samples) nor from the point of view of the individual foundation soil classes or the genetic types. The contribution of the paper is to point at the influence of genesis on the foundation soil properties so that engineering geologists and geotechnicians pay more attention to the genesis during engineering-geological and geotechnical investigations.

  1. Effect of Precuring Warming on Mechanical Properties of Restorative Composites

    Directory of Open Access Journals (Sweden)

    Kareem Nada

    2011-01-01

    Full Text Available To investigate the effect of prepolymerization warming on composites' mechanical properties, three composites were evaluated: Clearfil Majesty (CM (Kuraray, Z-100 (3M/ESPE, and Light-Core (LC (Bisco. Specimens were prepared from each composite at room temperature as control and 2 higher temperatures (37∘C and 54∘C to test surface hardness (SH, compressive strength (CS, and diametral tensile strength (DTS. Data were statistically analyzed using ANOVA and Fisher's LSD tests. Results revealed that prewarming CM and Z100 specimens significantly improved their SH mean values (P<0.05. Prewarming also improved mean CS values of Z100 specimens (P<0.05. Furthermore, DTS mean value of CM prepared at 52∘ was significantly higher than that of room temperature specimens (P<0.05. KHN, CS, and DTS mean values varied significantly among the three composites. In conclusion, Prewarming significantly enhanced surface hardness of 2 composites. Prewarming also improved bulk properties of the composites; however, this improvement was significant in only some of the tested materials.

  2. Mechanical properties and energy absorption characteristics of a polyurethane foam

    Energy Technology Data Exchange (ETDEWEB)

    Goods, S.H.; Neuschwanger, C.L.; Henderson, C.; Skala, D.M.

    1997-03-01

    Tension, compression and impact properties of a polyurethane encapsulant foam have been measured as a function of foam density. Significant differences in the behavior of the foam were observed depending on the mode of testing. Over the range of densities examined, both the modulus and the elastic collapse stress of the foam exhibited power-law dependencies with respect to density. The power-law relationship for the modulus was the same for both tension and compression testing and is explained in terms of the elastic compliance of the cellular structure of the foam using a simple geometric model. Euler buckling is used to rationalize the density dependence of the collapse stress. Neither tension nor compression testing yielded realistic measurements of energy absorption (toughness). In the former case, the energy absorption characteristics of the foam were severely limited due to the inherent lack of tensile ductility. In the latter case, the absence of a failure mechanism led to arbitrary measures of energy absorption that were not indicative of true material properties. Only impact testing revealed an intrinsic limitation in the toughness characteristics of the material with respect to foam density. The results suggest that dynamic testing should be used when assessing the shock mitigating qualities of a foam.

  3. Mechanical properties of polypropylene/calcium carbonate nanocomposites

    Directory of Open Access Journals (Sweden)

    Daniel Eiras

    2009-01-01

    Full Text Available The aim of this work was to study the influence of calcium carbonate nanoparticles in both tensile and impact mechanical properties of a polypropylene homopolymer. Four compositions of PP/CaCO3 nanocomposites were prepared in a co-rotational twin screw extruder machine with calcium carbonate content of 3, 5, 7 and 10 wt. (% The tests included SEM analyzes together with EDS analyzer and FTIR spectroscopy for calcium carbonate, tensile and impact tests for PP and the nanocomposites. The results showed an increase in PP elastic modulus and a little increase in yield stress. Brittle-to-ductile transition temperature was reduced and the impact resistance increased with the addition of nanoparticles. From the stress-strain curves we determined the occurrence of debonding process before yielding leading to stress softening. Debonding stress was determined from stress-strain curves corresponding to stress in 1% strain. We concluded that the tensile properties depend on the surface contact area of nanoparticles and on their dispersion. Finally we believe that the toughening was due to the formation of diffuse shear because of debonding process.

  4. Mechanical properties of carbon fiber composites for applications in space

    Science.gov (United States)

    Hana, P.; Inneman, A.; Daniel, V.; Sieger, L.; Petru, M.

    2015-01-01

    This article describes method of measurement mechanical properties of carbon fiber composites in space. New material structures are specifically designed for use on space satellites. Composite structures will be exposed to cosmic radiation in Earth orbit on board of a '2U CubeSat' satellite. Piezoelectric ceramic sensors are used for detection mechanical vibrations of composite test strip. A great deal of attention is paid to signal processing using 8-bit microcontroler. Fast Fourier Transformation is used. Fundamental harmonic frequencies and damping from on-board measurements will serve as the input data for terrestrial data processing. The other step of elaboration data is creation of the physical model for evaluating mechanical properties of Carbon composite - Piezoelectric ceramic system. Evaluation of anisotropic mechanical properties of piezoelectric ceramics is an interesting secondary outcome of the investigation. Extreme changes in temperature and the effect of cosmic rays will affect the mechanical properties and durability of the material used for the external construction of satellites. Comparative terrestrial measurements will be performed.

  5. Physical and mechanical properties of Tunisian women hair.

    Science.gov (United States)

    Sayahi, E; Harizi, T; Msahli, S; Sakli, F

    2016-10-01

    Mechanical analysis of human hair may provide the dermatologists with several markers of considerable diagnostic importance. The aim of this study was to analyse the physical and mechanical properties of Tunisian women's hair. Surface characteristics were determined with scanning electron microscopy (SEM). Mechanical properties were studied using the Miniature Tensile Tester Model 675 (MTT675), and the Fibre Dimensional Analysis Unit Model 765 (FDAS765) of Dia-Stron, UK, was used to measure the cross-sectional area. The cross-sectional area, stress at break, strain at break, elastic modulus and total work were 4643.21 ± 817 μm(2) , 201 ± 11.26 MPa, 47.3 ± 3.6%, 3.1 ± 0.16 GPa, and 9 ± 2.2 mJ, respectively. The effects of the factors 'hair curliness' and 'age' on the physical and mechanical properties were studied. The cross-sectional area and the break load are influenced by the factors 'age' and 'curl type', whereas Young's modulus shows a significant dependency only on the age. Tunisian women hair presented good mechanical properties as shown by a greater breaking stress and higher breaking strain. Both curl type and age are important factors to consider when evaluating the behaviour of hair. © 2016 Society of Cosmetic Scientists and the Société Française de Cosmétologie.

  6. Hydroxyapatite reinforced collagen scaffolds with improved architecture and mechanical properties.

    Science.gov (United States)

    Kane, Robert J; Weiss-Bilka, Holly E; Meagher, Matthew J; Liu, Yongxing; Gargac, Joshua A; Niebur, Glen L; Wagner, Diane R; Roeder, Ryan K

    2015-04-01

    Hydroxyapatite (HA) reinforced collagen scaffolds have shown promise for synthetic bone graft substitutes and tissue engineering scaffolds. Freeze-dried HA-collagen scaffolds are readily fabricated and have exhibited osteogenicity in vivo, but are limited by an inherent scaffold architecture that results in a relatively small pore size and weak mechanical properties. In order to overcome these limitations, HA-collagen scaffolds were prepared by compression molding HA reinforcements and paraffin microspheres within a suspension of concentrated collagen fibrils (∼ 180 mg/mL), cross-linking the collagen matrix, and leaching the paraffin porogen. HA-collagen scaffolds exhibited an architecture with high porosity (85-90%), interconnected pores ∼ 300-400 μm in size, and struts ∼ 3-100 μm in thickness containing 0-80 vol% HA whisker or powder reinforcements. HA reinforcement enabled a compressive modulus of up to ∼ 1 MPa, which was an order of magnitude greater than unreinforced collagen scaffolds. The compressive modulus was also at least one order of magnitude greater than comparable freeze-dried HA-collagen scaffolds and two orders of magnitude greater than absorbable collagen sponges used clinically. Moreover, scaffolds reinforced with up to 60 vol% HA exhibited fully recoverable elastic deformation upon loading to 50% compressive strain for at least 100,000 cycles. Thus, the scaffold mechanical properties were well-suited for surgical handling, fixation, and bearing osteogenic loads during bone regeneration. The scaffold architecture, permeability, and composition were shown to be conducive to the infiltration and differentiation of adipose-derive stromal cells in vitro. Acellular scaffolds were demonstrated to induce angiogenesis and osteogenesis after subcutaneous ectopic implantation by recruiting endogenous cell populations, suggesting that the scaffolds were osteoinductive.

  7. Heritability of lumbar trabecular bone mechanical properties in baboons.

    Science.gov (United States)

    Havill, L M; Allen, M R; Bredbenner, T L; Burr, D B; Nicolella, D P; Turner, C H; Warren, D M; Mahaney, M C

    2010-03-01

    Genetic effects on mechanical properties have been demonstrated in rodents, but not confirmed in primates. Our aim was to quantify the proportion of variation in vertebral trabecular bone mechanical properties that is due to the effects of genes. L3 vertebrae were collected from 110 females and 46 male baboons (6-32 years old) from a single extended pedigree. Cranio-caudally oriented trabecular bone cores were scanned with microCT then tested in monotonic compression to determine apparent ultimate stress, modulus, and toughness. Age and sex effects and heritability (h(2)) were assessed using maximum likelihood-based variance components methods. Additive effects of genes on residual trait variance were significant for ultimate stress (h(2)=0.58), toughness (h(2)=0.64), and BV/TV (h(2)=0.55). When BV/TV was accounted for, the residual variance in ultimate stress accounted for by the additive effects of genes was no longer significant. Toughness, however, showed evidence of a non-BV/TV-related genetic effect. Overall, maximum stress and modulus show strong genetic effects that are nearly entirely due to bone volume. Toughness shows strong genetic effects related to bone volume and shows additional genetic effects (accounting for 10% of the total trait variance) that are independent of bone volume. These results support continued use of bone volume as a focal trait to identify genes related to skeletal fragility, but also show that other focal traits related to toughness and variation in the organic component of bone matrix will enhance our ability to find additional genes that are particularly relevant to fatigue-related fractures.

  8. Correlation of microstructure and thermo-mechanical properties of a novel hydrogen transport membrane

    Science.gov (United States)

    Zhang, Yongjun

    more like an elastic material at room temperature and as a ductile material at temperature above 850°C. The oxidation and the plasticity of Pd phase mainly affected the mechanical properties of HTM cermet at high temperature, also as a result of thermal cycling. Residual stress induced in the HTM by thermo cycles also plays a very critical role in defining the thermo-mechanical properties.

  9. Comparative Study on Mechanical Properties between Pure and Recycled Polypropylenes

    Directory of Open Access Journals (Sweden)

    Ariadne L. Juwono

    2010-04-01

    Full Text Available Polypropylene (PP is one type of thermoplastics that is widely used in our daily activities. A combination of the high demand and the easiness of recycling process, the recycled PP has been generally applied. In this study, the structure and the mechanical properties of the as-received PPs, recycled PPs, and commercial recycled PPs were compared, especially for cloth hanger application. DSC test results showed that recycling process did not cause a significant change to the material's melting point, which stayed in a range of 160-163 oC. Meanwhile, FTIR test results showed that the commercial recycled PPs contained of Polyethylene (PE, which was not found in the as-received and the recycled PPs. Tensile and hardness tests demonstrated that there were no significant differences between the as-received and recycled PPs. In contrast, tensile test results of the commercial recycled PPs showed that the tensile strength, Young modulus and strain-at-break were lower than those of the as-received PPs by 22.1%, 8.1% and 65.7% respectively. The hardness test results of the commercial recycled PPs showed that the recycling process had a little effect on the material's hardness. These facts were supported by SEM observation on the surface that the contour of the commercial recycled PPs was relatively flatter and had smaller grain size than those of the as-received PPs. This indicated that the commercial recycled PPs were more brittle compared to the recycled PPs. To conclude, the recycled PPs have similar properties to the as-received PPs so that recycled PPs are suitable to be applied as cloth hanger application.

  10. A comparative study on the synthesis mechanism, bioactivity and mechanical properties of three silicate bioceramics.

    Science.gov (United States)

    Najafinezhad, Aliakbar; Abdellahi, Majid; Ghayour, Hamid; Soheily, Ali; Chami, Akbar; Khandan, Amirsalar

    2017-03-01

    In the present study three akermanite (Ca2MgSi2O7), diopside (CaMgSi2O6) and baghdadite (Ca3ZrSi2O9) applicable bioceramics were synthesized via a sol-gel based method. The combination of sol-gel method and the raw materials used in this study presents a new route for the synthesis of the mentioned bioceramics. By the use of thermal analysis, the mechanisms occurred during the synthesis of these bioceramics were investigated. The differences in the structural density and their relation with the degradation rate and mechanical properties of all three ceramics were studied. In vitro bioactivity and apatite formation mechanisms of the samples soaked in the simulated body fluid were considered. The results showed that baghdadite as a Zr-containing material has a more dense structure in comparison with the other ceramics, which leads to a lower degradation rate and also lower bioactivity. There were also main differences between akermanite and diopside as Mg-containing ceramics. Diopside showed a structure with lower porosity content compared to the akermanite samples which resulted in the lower degradation rate and higher compressive strength. Copyright © 2016 Elsevier B.V. All rights reserved.

  11. Hollow polyelectrolyte multilayer tubes: mechanical properties and shape changes.

    Science.gov (United States)

    Mueller, Renate; Daehne, Lars; Fery, Andreas

    2007-07-26

    In this paper, novel hollow polyelectrolyte multilayer tubes from poly(diallyldimethylammonium chloride) (PDADMAC), poly(styrene sulfonate) (PSS), and poly(allylamine hydrochloride) (PAH) were prepared: Readily available glass fiber templates are coated with polyelectrolytes using the layer-by-layer technique, followed by subsequent fiber dissolution. Depending on the composition of the polymeric multilayer, stable hollow tubes or tubes showing a pearling instability are observed. This instability corresponds to the Rayleigh instability and is a consequence of an increased mobility of the polyelectrolyte chains within the multilayer. The well-defined stable tubes were characterized with fluorescence microscopy, confocal laser scanning microscopy, and atomic force microscopy (AFM). The tubes were found to be remarkably free of defects, which results in an impermeable tube wall for even low molecular weight molecules. The mechanical properties of the tubes were determined with AFM force spectroscopy in water, and because continuum mechanical models apply, the Young's modulus of the wall material was determined. Additionally, scaling relations for the dependency of tube stiffness on diameter and wall thickness were validated. Because both parameters can be experimentally controlled by our approach, the deformability of the tubes can be varied over a broad range and adjusted for the particular needs.

  12. Nanobioceramic Composites: A Study of Mechanical, Morphological, and Thermal Properties

    Directory of Open Access Journals (Sweden)

    Sivabalan Sasthiryar

    2013-12-01

    Full Text Available The aim of this study was to explore the incorporation of biomass carbon nanofillers (CNF into advanced ceramic. Biomass from bamboo, bagasse (remains of sugarcane after pressing, and oil palm ash was used as the predecessor for producing carbon black nanofillers. Furnace pyrolysis was carried out at 1000 °C and was followed by ball-mill processing to obtain carbon nanofillers in the range of 50 nm to 100 nm. CNFs were added to alumina in varying weight fractions and the resulting mixture was subjected to vacuum sintering at 1400 °C to produce nanobioceramic composites. The ceramic composites were characterized for mechanical, thermal, and morphological properties. A high-resolution Charge-coupled device (CCD camera was used to study the fracture impact and the failure mechanism. An increase in the loading percentage of CNFs in the alumna decreased the specific gravity, vickers hardness (HV, and fracture toughness values of the composite materials. Furthermore, the thermal conductivity and the thermal stability of the ceramic composite increased as compared to the pristine alumina.

  13. Molecular Fundaments of Mechanical Properties of Spider Silk

    Institute of Scientific and Technical Information of China (English)

    潘志娟; 刘敏; 李春萍; 李栋高; 盛家镛

    2003-01-01

    Dragline,framework and cocoon silk fibers of Araneus Ventricosus were used for this study.To investigate the microstructure mechanisms of stress-strain behavior of spider silk,firstly,amino acid compositions were analyzed and molecular conformations and crystallinity were measured with Raman spectra and X-ray diffraction respectively.The results showed that there were more amino acids with large side groups and polar ones in spider silk than those of Bombyx silk,and the amino acid distribution varied with different spider silk.The molecular structures were mainly α-helix and β-sheet,and random coil and β-turn existed as well.The proportions and arrangement of these conformations of dragline silk were different from framework and cocoon silk fibers.Microstructure was one of important factors of excellent mechanical properties of spider silk.Crystallinity of spider silk was very low,which implied that the roles of crystal on spider silk were not as great as other protein fibers.

  14. Influence of hot extrusion on microstructure and mechanical properties of AZ31 magnesium alloy

    Institute of Scientific and Technical Information of China (English)

    WANG Ling; TIAN Su-gui; MENG Fan-lai; DU Hong-qiang

    2006-01-01

    Extrusion treatment is a common method to refine the grain size and improve the mechanical properties of metal material. The influence of hot extrusion on microstructure and mechanical properties of AZ31 magnesium alloy was investigated. The results show that the mechanical properties of AZ31 alloy are obviously improved by extrusion treatment. The ultimate tensile strength (UTS) of AZ31 alloy at room temperature is measured to be 222 MPa, and is enhanced to 265.8 MPa after extrusion at 420℃. The yield tensile strength (YTS) of AZ31 alloy at room temperature is measured to be 84 MPa, and is enhanced to 201 MPa after extrusion at 420℃. The effective improvements on mechanical properties result from the formation of the finer grains during extrusion and the finer particles precipitated by age treatment. The features of the microstructure evolution during hot extruded of AZ31 alloy are dislocation slipping on the matrix and occurrence of the dynamic recrystallization.

  15. Effects of welding parameters on the mechanical properties of inert gas welded 6063 Aluminium alloys

    Energy Technology Data Exchange (ETDEWEB)

    Ertan, Taner [MAKO Corporation (Turkey); Uguz, Agah [Uludag Univ. (Turkey). Mechnical Engineering Dept.; Ertan, Rukiye

    2012-07-01

    The influence of welding parameters, namely welding current and gas flow rate, on the mechanical properties of Gas Tungsten Arc Welding (GTAW) and Shielded Metal Arc Welding (SMAW) welded 6063 Aluminum alloy (AA 6063) has been investigated. In order to study the effect of the welding current and gas flow rate, microstructural examination, hardness measurements and room temperature tensile tests have been carried out. The experimental results show that the mechanical properties of GTAW welded joints have better mechanical properties than those of SMAW welded joints. Increasing the welding current appeared to have a beneficial effect on the mechanical properties. However, either increasing or decreasing the gas flow rate resulted in a decrease of hardness and tensile strength. It was also found that, the highest strength was obtained in GTAW welded samples at 220 A and 15 l/min gas flow rate.

  16. The effects of multiple repairs on Inconel 718 weld mechanical properties

    Science.gov (United States)

    Russell, C. K.; Nunes, A. C., Jr.; Moore, D.

    1991-01-01

    Inconel 718 weldments were repaired 3, 6, 9, and 13 times using the gas tungsten arc welding process. The welded panels were machined into mechanical test specimens, postweld heat treated, and nondestructively tested. Tensile properties and high cycle fatigue life were evaluated and the results compared to unrepaired weld properties. Mechanical property data were analyzed using the statistical methods of difference in means for tensile properties and difference in log means and Weibull analysis for high cycle fatigue properties. Statistical analysis performed on the data did not show a significant decrease in tensile or high cycle fatigue properties due to the repeated repairs. Some degradation was observed in all properties, however, it was minimal.

  17. Mechanical Properties Comparing Composite Fiber Length to Amalgam

    Directory of Open Access Journals (Sweden)

    Richard C. Petersen

    2016-01-01

    Full Text Available Photocure fiber-reinforced composites (FRCs with varying chopped quartz-fiber lengths were incorporated into a dental photocure zirconia-silicate particulate-filled composite (PFC for mechanical test comparisons with a popular commercial spherical-particle amalgam. FRC lengths included 0.5-mm, 1.0 mm, 2.0 mm, and 3.0 mm all at a constant 28.2 volume percent. Four-point fully articulated fixtures were used according to American Standards Test Methods with sample dimensions of 2×2×50 mm3 across a 40 mm span to provide sufficient Euler flexural bending and prevent top-load compressive shear error. Mechanical properties for flexural strength, modulus, yield strength, resilience, work of fracture, critical strain energy release, critical stress intensity factor, and strain were obtained for comparison. Fiber length subsequently correlated with increasing all mechanical properties, p<1.1×10-5. Although the modulus was significantly statistically higher for amalgam than all composites, all FRCs and even the PFC had higher values than amalgam for all other mechanical properties. Because amalgams provide increased longevity during clinical use compared to the standard PFCs, modulus would appear to be a mechanical property that might sufficiently reduce margin interlaminar shear stress and strain-related microcracking that could reduce failure rates. Also, since FRCs were tested with all mechanical properties that statistically significantly increased over the PFC, new avenues for future development could be provided toward surpassing amalgam in clinical longevity.

  18. Mechanical Properties of a Unidirectional Basalt-Fiber-Reinforced Plastic Under a Loading Simulating Operation Conditions

    Science.gov (United States)

    Lobanov, D. S.; Slovikov, S. V.

    2017-01-01

    The results of experimental investigations of unidirectional composites based on basalt fibers and different marks of epoxy resins are presented. Uniaxial tensile tests were carried out using a specimen fixation technique simulating the operation conditions of structures. The mechanical properties of the basalt-fiber-reinforced plastics (BFRPs) were determined. The diagrams of loading and deformation of BFRP specimens were obtain. The formulations of the composites with the highest mechanical properties were revealed.

  19. Effects of Anatomical Characteristics of Ethiopian Lowland Bamboo on Physical and Mechanical Properties

    Institute of Scientific and Technical Information of China (English)

    SEYOUM; Kelemwork

    2009-01-01

    The main aim of this study was to evaluate the effects of anatomical characteristics of Ethiopian lowland bamboo on selected physical and mechanical properties. A total of 45 solid culms from three different age groups (2-, 3- and 4- year-old) were harvested from natural bamboo forest in Ethiopia and then samples were transported to China for carrying out anatomical characteristics test. Physical and mechanical properties testing were conducted in Ethiopia. The result indicates that age and height had signi...

  20. Relationship between Ballistic Coefficient and Static Mechanical Properties for Armor Materials

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    The relationship between the ballistic coefficient and the static mechanical properties of armor materials was studied. The results show that the ballistic coefficient is determined by the strength, hardness and the toughness of materials. According to the Martel rule, the equation of the relationship between ballistic coefficient and static mechanical properties satisfies the following formula: . From the mixture law of composite, the prerequisite, for which ballistic coefficient has maximum to reinforcement volume fraction, is obtained by the following equation: .

  1. Mechanical Property of Low Chromium Semi-Steel Grinding Ball Prepared by Cross Rolling

    Institute of Scientific and Technical Information of China (English)

    CHANG Li-min; MENG De-liang; NIE Pu-lin; LIU Jian-hua

    2004-01-01

    The preparing method, rolling technology and mechanical properties of low chromium semi-steel grinding ball by cross rolling were studied. The results show that when the low chromium semi-steel bar is forged from 55 mm to 50 mm, cross-rolled into grinding ball at 1 000-1 050 ℃, air cooled and tempered at 550 ℃ for 2 h, the best mechanical properties, especially the abrasive resistance under the action of hard abrasive, can be obtained.

  2. The effects of starches on mechanical properties of paracetamol tablet formulations. I. Pregelatinization of starch binders.

    Science.gov (United States)

    Alebiowu, Gbenga; Itiola, Oludele Adelanwa

    2003-09-01

    A study has been made of the effects of pregelatinization of native sorghum and plantain starches on the mechanical properties of a paracetamol tablet formulation in comparison with corn starch BP. The mechanical properties tested, viz. tensile strength (T) and brittle fracture index (BFI) of the paracetamol tablets were affected by pregelatinization of the starch. The results suggest that pregelatinized starches may be useful as binders when a particular degree of bond strength and brittleness is desired.

  3. Mechanical properties of tricalcium phosphate-alumina composites

    Science.gov (United States)

    Sakka, S.; Ben Ayed, F.; Bouaziz, J.

    2012-02-01

    Tricalcium phosphate and alumina powder were mixed in order to elaborate biphasic ceramics composites. This study deals to produce bioceramics composites sintered at various temperatures for differents times. The characterization of samples, before and after the sintering process was investigated, using X-Ray diffraction, scanning electronic microscopy, 31P and 27Al nuclear magnetic resonance and differential thermal analysis. Mechanical properties of biphasic composites were studied using Brazilian test. The tricalcium phosphate - 75 wt% alumina composites mechanical resistance increased with sintered temperature. The mechanical resistance reach it's optimum value (8.6 MPa) at 1550°C for two hours.

  4. Mechanical properties of titanium alloys with strengthened surface layers

    Directory of Open Access Journals (Sweden)

    I.M. Pohreliuk

    2011-12-01

    Full Text Available Influence of oxinitriding and boriding on the mechanical properties (ultimate strength to destruction at uniaxial tension, plasticity, tendency to delayed destruction, fatigue resistance at bending with rotation, fatigue life at lowcycle pure bending of titanium alloys is studied.

  5. THE RHEOLOGICAL PROPERTIES AND OUTBURST MECHANISM OF GASEOUS COAL

    Institute of Scientific and Technical Information of China (English)

    何学秋; 周世宁; 林柏泉

    1991-01-01

    Coal and methane outburst is one of the harmful disasters in coal mines. We have studied the rheological properties of gaseous coal in laboratory and obtained its rheological fracture principle. This principle can better explain and describe the outburst mechanism of gaseous coal. Thereby a rheological hypothesis of coal and methane outburst is put forward in this paper.

  6. assessment of some mechanical properties and microstructure of ...

    African Journals Online (AJOL)

    user

    the composites and those of the aluminium 6063 (AA6063) alloy. ... Key words: Composites, Periwinkle shell, Aluminum, Mechanical properties, Microstructure. 1. .... In this work, we evaluated the effect of particle size and ... Zr. V. Ca. Be. Average content. 0.0347. 0.0566. ... micro structural study. 3.

  7. Temperature dependence of poly(lactic acid) mechanical properties

    DEFF Research Database (Denmark)

    Zhou, Chengbo; Guo, Huilong; Li, Jingqing

    2016-01-01

    The mechanical properties of polymers are not only determined by their structures, but also related to the temperature field in which they are located. The yield behaviors, Young's modulus and structures of injection-molded poly(lactic acid) (PLA) samples after annealing at different temperatures...

  8. Mechanical Properties, Purifying Techniques and Processing Methods of Metal Yttrium

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    The mechanical properties of metal yttrium such as strength, plasticity, hardness and elasticity were introduced. The purifying techniques of yttrium were discussed in detail. The processing methods for metal yttrium including extruding, forging, rolling, wiredrawing and welding were also introduced. Finally, the potential use of yttrium and its alloys were prospected.

  9. 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.

  10. Mechanical properties of porous, electrosprayed calcium phosphate coatings

    NARCIS (Netherlands)

    Leeuwenburgh, S.C.G.; Wolke, J.G.C.; Lommen, L.; Pooters, T.; Schoonman, J.; Jansen, J.A.

    2006-01-01

    Mechanical properties of calcium phosphate coatings (CaP), deposited using the electrostatic spray deposition (ESD) technique, have been characterized using a range of analytical techniques, including tensile testing (ASTM C633), fatigue testing (ASTM E855), and scratch testing using blunt and sharp

  11. 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 also used to e

  12. 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 in this .... Cu. Zn. Mn. Mg. Cr. B. 99.71. 0.045. -. 0.230. 0.002. 0.006. 0.001. 0.001. 0.001. 0.004 ..... Iron & Steel Making, MIR Publishers, Moscow,. 39. 1983. 40. 41.

  13. Switchable antimicrobial and antifouling hydrogels with enhanced mechanical properties.

    Science.gov (United States)

    Cao, Bin; Tang, Qiong; Li, Linlin; Humble, Jayson; Wu, Haiyan; Liu, Lingyun; Cheng, Gang

    2013-08-01

    New switchable hydrogels are developed. Under acidic conditions, hydrogels undergo self-cyclization and can catch and kill bacteria. Under neutral/basic conditions, hydrogels undergo ring-opening and can release killed bacterial cells and resist protein adsorption and bacterial attachment. Smart hydrogels also show a dramatically improved mechanical property, which is highly desired for biomedical applications.

  14. Mechanical properties of ultra-fine grained zirconia ceramics

    NARCIS (Netherlands)

    Theunissen, G.S.A.M.; Bouma, J.S.; Winnubst, A.J.A.; Burggraaf, A.J.

    1992-01-01

    The mechanical properties of tetragonal zirconia (TZP) materials doped with Y, Ce or Ti were studied as a function of temperature and grain size. Fine grained Y-TZP (grain size < 0.3 mgrm) shows values for fracture toughness and strength at room temperature, which are comparable with the coarse grai

  15. Theoretical Modeling of Mechanical Behavior and Release Properties of Microcapsules

    NARCIS (Netherlands)

    Sagis, L.M.C.

    2015-01-01

    Microcapsules in food often have a shell with a complex microstructure; the mechanical and structural properties of these shells affect the response of the capsules to deforming forces and the release kinetics of encapsulated components. In this chapter we will discuss a number of models which are t

  16. 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.

  17. Relationships among the structural topology, bond strength, and mechanical properties of single-walled aluminosilicate nanotubes.

    Science.gov (United States)

    Liou, Kai-Hsin; Tsou, Nien-Ti; Kang, Dun-Yen

    2015-10-21

    Carbon nanotubes (CNTs) are regarded as small but strong due to their nanoscale microstructure and high mechanical strength (Young's modulus exceeds 1000 GPa). A longstanding question has been whether there exist other nanotube materials with mechanical properties as good as those of CNTs. In this study, we investigated the mechanical properties of single-walled aluminosilicate nanotubes (AlSiNTs) using a multiscale computational method and then conducted a comparison with single-walled carbon nanotubes (SWCNTs). By comparing the potential energy estimated from molecular and macroscopic material mechanics, we were able to model the chemical bonds as beam elements for the nanoscale continuum modeling. This method allowed for simulated mechanical tests (tensile, bending, and torsion) with minimum computational resources for deducing their Young's modulus and shear modulus. The proposed approach also enabled the creation of hypothetical nanotubes to elucidate the relative contributions of bond strength and nanotube structural topology to overall nanotube mechanical strength. Our results indicated that it is the structural topology rather than bond strength that dominates the mechanical properties of the nanotubes. Finally, we investigated the relationship between the structural topology and the mechanical properties by analyzing the von Mises stress distribution in the nanotubes. The proposed methodology proved effective in rationalizing differences in the mechanical properties of AlSiNTs and SWCNTs. Furthermore, this approach could be applied to the exploration of new high-strength nanotube materials.

  18. Custom impression trays: Part I--Mechanical properties.

    Science.gov (United States)

    Breeding, L C; Dixon, D L; Moseley, J P

    1994-01-01

    Dimensional stability of custom impression trays is an important factor in determining the degree of accuracy achieved in forming a master cast. Such trays must remain stable over time and must not exhibit permanent deformation when a completed impression is removed from the oral cavity. Measurement of the mechanical properties allows comparison between various tray materials and is useful in interpreting data on stresses incurred during removal of the completed impression. In Part I of this three-part series, the various mechanical properties of five tray resins: one autopolymerizing polymethyl methacrylate, one light-polymerizing, and three brands of thermoplastic resins were recorded and compared. The thermoplastic resins studied in this investigation exhibited lower measured values for the strength and elastic modulus properties than the light-polymerizing resin and the autopolymerizing polymethyl methacrylate resin studied.

  19. Using cell monolayer rheology to probe average single cell mechanical properties.

    Science.gov (United States)

    Sander, Mathias; Flesch, Julia; Ott, Albrecht

    2015-01-01

    The cell monolayer rheology technique consists of a commercial rotational rheometer that probes the mechanical properties of a monolayer of isolated cells. So far we have described properties of an entire monolayer. In this short communication, we show that we can deduce average single cell properties. Results are in very good agreement with earlier work on single cell mechanics. Our approach provides a mean of 105-106 adherent cells within a single experiment. This makes the results very reproducible. We extend our work on cell adhesion strength and deduce cell adhesion forces of fibroblast cells on fibronectin coated glass substrates.

  20. Influence of Magnetic Pulseprocessing on Oxide Materials Physics and Mechanical Properties

    Directory of Open Access Journals (Sweden)

    M.N. Shipko

    2014-07-01

    Full Text Available Internal stresses, specific single-crystal blocks, stoichiometric impurity of oxides composition and other factors lead to low strength properties of ferromagnetic iron oxides. Weakening of such defects and increasing iron oxides microhardness, their fracture and mechanic strength are possible by using magnetic pulse processing. The results of experimental studies of the magnetic pulse field effecting on the iron oxides strength properties are shown. Mössbauer spectroscopy, porosimetry, X-ray structure analysis are used to find the mechanisms of this effect. The strength properties change is the result of set of microscopic and quantum effects superposition. It provides easy defects restructuring of solids: vacancies, dislocations, voids.

  1. Prediction of mechanical property of E4303 electrode using artificial neural network

    Institute of Scientific and Technical Information of China (English)

    徐越兰; 黄俊; 王克鸿

    2004-01-01

    Based on the method of artificial neural network, a new approach has been devised to predict the mechanical property of E4303 electrode. The outlined predication model for determining the mechanical property of electrode was built upon the production data. The research leverages a back propagation algorithm as the neural network's learning rule. The result indicates that there are positive correlations between the predicted results and the practical production data. Hence, using the neural network, predication of electrode property can be realized. For the first time, this research provides a more scientific method for designing electrode.

  2. Intraspecific variability of European larch for wood properties: Preliminary results

    Energy Technology Data Exchange (ETDEWEB)

    Paques, L.E.; Rozenberg, P. [Institut National de Recherches Agronomiques (INRA), 45 - Olivet (France). Station d`Amelioration des Arbres Forestiers

    1995-12-31

    Wood properties of several natural populations of European larch (Larix decidua Mill) were determined from samples collected in one replicate of the II. International IUFRO provenance experiment, planted in Brittany in 1959. According to provenances, proportion of heartwood ranges from 35 to 58% of basal area, basic density from 442 to 505 g/dm{sup 3} and Young modulus of elasticity from 8474 to 14522 MPa. Positive correlations between girth and heartwood proportion and between wood density and modulus of elasticity but negative correlations between ring width and both density and MOE have been found both at the individual and at the population levels. Variability between and within provenances is high for two major traits (proportion of heartwood and Young modulus of elasticity) for which a SW - NE gradient is shown. For wood density parameters including pilodyn, a greater homogeneity is observed. Besides a now largely recognized superiority for growth traits, Central European populations from the Sudetan Mountains and Central Poland would also produce wood with better properties. On the reverse, Alpine populations from the French Alps growing at low elevations have a slower growth, a denser wood with less heartwood and less strength. Used as a control, the hybrid larch origin (Larix x eurolepis) represents the best compromise for wood properties with the highest strength but an average wood density and one of the highest proportion of heartwood. These preliminary results must be confirmed from a larger set of provenances and completed with other major wood properties such as durability and shrinkage. 17 refs, 2 figs, 6 tabs

  3. Brillouin microspectroscopy of nanostructured biomaterials: photonics assisted tailoring mechanical properties

    Science.gov (United States)

    Meng, Zhaokai; Jaiswal, Manish K.; Chitrakar, Chandani; Thakur, Teena; Gaharwar, Akhilesh K.; Yakovlev, Vladislav V.

    2016-03-01

    Developing new biomaterials is essential for the next-generation of materials for bioenergy, bioelectronics, basic biology, medical diagnostics, cancer research, and regenerative medicine. Specifically, recent progress in nanotechnology has stimulated the development of multifunctional biomaterials for tissue engineering applications. The physical properties of nanocomposite biomaterials, including elasticity and viscosity, play key roles in controlling cell fate, which underlines therapeutic success. Conventional mechanical tests, including uniaxial compression and tension, dynamic mechanical analysis and shear rheology, require mechanical forces to be directly exerted onto the sample and therefore may not be suitable for in situ measurements or continuous monitoring of mechanical stiffness. In this study, we employ spontaneous Brillouin spectroscopy as a viscoelasticity-specific probing technique. We utilized a Brillouin spectrometer to characterize biomaterial's microscopic elasticity and correlated those with conventional mechanical tests (e.g., rheology).

  4. Use of Artificial Neural Network for Predicting the Mechanical Property of Low Carbon Steel

    OpenAIRE

    Somkuwar, Vandana

    2013-01-01

    For product development manufacturers and designers need information about the existing materials and new material and its properties as early as possible. This paper presents a method of predicting the properties of unknown material using artificial neural network. The developed neural network model is employed for simulations of the relationship between mechanical property and the chemical composition of low carbon steel. Simulating and analyzing result shows that network model can effectiv...

  5. Supersymmetric quantum mechanics on the lattice: II. Exact results

    Directory of Open Access Journals (Sweden)

    David Baumgartner

    2015-08-01

    Full Text Available Simulations of supersymmetric field theories with spontaneously broken supersymmetry require in addition to the ultraviolet regularisation also an infrared one, due to the emergence of the massless Goldstino. The intricate interplay between ultraviolet and infrared effects towards the continuum and infinite volume limit demands careful investigations to avoid potential problems. In this paper – the second in a series of three – we present such an investigation for N=2 supersymmetric quantum mechanics formulated on the lattice in terms of bosonic and fermionic bonds. In one dimension, the bond formulation allows to solve the system exactly, even at finite lattice spacing, through the construction and analysis of transfer matrices. In the present paper we elaborate on this approach and discuss a range of exact results for observables such as the Witten index, the mass spectra and Ward identities.

  6. Supersymmetric quantum mechanics on the lattice: II. Exact results

    CERN Document Server

    Baumgartner, David

    2015-01-01

    Simulations of supersymmetric field theories with spontaneously broken supersymmetry require in addition to the ultraviolet regularisation also an infrared one, due to the emergence of the massless Goldstino. The intricate interplay between ultraviolet and infrared effects towards the continuum and infinite volume limit demands careful investigations to avoid potential problems. In this paper -- the second in a series of three -- we present such an investigation for ${\\cal N}=2$ supersymmetric quantum mechanics formulated on the lattice in terms of bosonic and fermionic bonds. In one dimension, the bond formulation allows to solve the system exactly, even at finite lattice spacing, through the construction and analysis of transfer matrices. In the present paper we elaborate on this approach and discuss a range of exact results for observables such as the Witten index, the mass spectra and Ward identities.

  7. The mechanical properties of the human hip capsule ligaments.

    Science.gov (United States)

    Hewitt, John D; Glisson, Richard R; Guilak, Farshid; Vail, T Parker

    2002-01-01

    The human hip capsule is adapted to facilitate upright posture, joint stability, and ambulation, yet it routinely is excised in hip surgery without a full understanding of its mechanical contributions. The objective of this study was to provide information about the mechanical properties of the ligaments that form the hip capsule. Cadaver bone-ligament-bone specimens of the iliofemoral, ischiofemoral, and femoral arcuate ligaments were tested to failure in tension. The hip capsule was found to be an inhomogeneous structure and should be recognized as being composed of discrete constituent ligaments. The anterior ligaments, consisting of the 2 arms of the iliofemoral ligament, were much stronger than the posterior ischiofemoral ligament, withstanding greater force at failure and exhibiting greater stiffness. Knowledge of the anatomy and mechanical properties of the capsule may help the hip surgeon choose an appropriate surgical approach or repair strategy.

  8. Results of monitoring at Olkiluoto in 2013, rock mechanics

    Energy Technology Data Exchange (ETDEWEB)

    Johansson, E. (ed.) [Saanio and Riekkola Oy, Helsinki (Finland)

    2014-10-15

    The rock mechanics monitoring at Olkiluoto concentrates on the assessment of potential tectonic movements and stability of the bedrock. The rock mechanics monitoring programme 2013 consisted of seismic measurements, GPS measurements, surface levelling measurements and temperature measurements at Olkiluoto and vicinity and displacement measurements, temperature measurements and visual tunnel observations made in the ONKALO. The Posiva's microseismic network consists of 17 seismic stations and 21 triaxial sensors. Five stations are in the ONKALO. In spite of few breaks the network operated continuously and well during 2013. The number of located events (436) was slightly more than in 2012, but much less than in 2011. Nearly half of the observed explosions (237) in 2013 occurred inside the seismic semi-regional area and especially inside the seismic ONKALO block (137). One small induced earthquake (M{sub L} = -1.8) was detected at the depth of 429 m and was probably associated with smaller branches of the brittle fracture zone (OL-BFZ045). According to the seismic monitoring the rock mass has been stable in 2013. The local GPS network consists of 18 stations. Six new stations were set up for permanent tracking during 2013 and in total 12 permanent stations are now operating continuously. Manual measurements were carried out twice in 2013. Most of the inner network baselines showed very small motions as in the previous years: 75% of change rates were smaller than 0.10 mm/y. Roughly one third of the change rates are statistically significant. The surface levelling network currently consists of 87 fixed measuring points. During 2013 all the measuring loops were measured. The results indicated local subsidence area in the ONKALO loop and the rising area in the VLJ loop. Mean deformation rate has been +0.05 mm/y. Only elevation of one benchmark in the GPS station loop has changed more than one millimetre. The continuous displacement measurements in the technical rooms

  9. Mechanical properties of attapulgite clay reinforced polyurethane shape-memory nanocomposites

    NARCIS (Netherlands)

    Xu, Bin; Huang, W.M.; Pei, Y.T.; Chen, Zhenguo; Kraft, A.; Reuben, R.; Hosson, J.Th.M. De; Fu, Y.Q.

    Nanocomposites based on attapulgite clay and shape-memory polyurethane were fabricated by mechanical mixing. The mechanical properties of samples were evaluated using a micro-indentation tester. The untreated commercial attapulgite clay resulted in a significant decrease in glass transition

  10. Mechanical properties of attapulgite clay reinforced polyurethane shape-memory nanocomposites

    NARCIS (Netherlands)

    Xu, Bin; Huang, W.M.; Pei, Y.T.; Chen, Zhenguo; Kraft, A.; Reuben, R.; Hosson, J.Th.M. De; Fu, Y.Q.

    2009-01-01

    Nanocomposites based on attapulgite clay and shape-memory polyurethane were fabricated by mechanical mixing. The mechanical properties of samples were evaluated using a micro-indentation tester. The untreated commercial attapulgite clay resulted in a significant decrease in glass transition temperat

  11. TANNED LEATHERS PROPERTIES MODIFICATION AS A RESULT OF ARTIFICIAL AGEING

    Directory of Open Access Journals (Sweden)

    ROŞU Dan

    2017-05-01

    Full Text Available Leather is a high tech material with different application fields, such as automotive, manufacturing of leatherwear articles or clothing and footwear. Leather is a biomaterial obtained by processing animal skins. Unfortunately, raw animal hides are practically inutilizable, due to their microbiological instability and are affected by rotting. Microbiological stability is achieved by tanning, when the protein is crosslinked, followed by drying. After crosslinking and drying, the new material shows the required properties of sustainability, availability and an esthetically pleasing aspect to the touch, making it available across its entire range of applications. From a structural point of view the animal skins are constituted of collagen, which is a fibrilar protein with a high degree of supramolecular organization in triple helix form that endows softness, elasticity and mechanical strength. High quality standards and lack of toxicity are required in all cases. Leather colour changes during exposure to light radiations are considered a consequence of the presence of some products with weak photochemical resistance during fabrication. The study aims to compare changes in properties of leathers obtained using mineral tanning agents such as Cr III salts and those obtained with the more environment-friendly technology using acid hydrolysis. Accelerated aging studies were conducted on tanned leathers by exposing the samples to UV radiation with different irradiation doses and two wavelengths (254 and 365 nm under controlled humidity and temperature conditions. Structural changes caused by irradiation were studied by FTIR. Colour changes on the sample surfaces were assessed during irradiation with the CIEL a*b* system. The colour parameters variation (L*, a*, b* and colour differences have been discussed in correlation with structural changes, tanning method and irradiation conditions.

  12. The mechanical and acoustic properties of two-dimensional pentamode metamaterials with different structural parameters

    Science.gov (United States)

    Cai, Xuan; Wang, Lei; Zhao, Zhigao; Zhao, Aiguo; Zhang, Xiangdong; Wu, Tao; Chen, Hong

    2016-09-01

    The effective mechanical and acoustic properties of two-dimensional pentamode metamaterials (PMs) with different structural parameters are investigated in this paper. It is found that with varying structural parameters, the effective bulk modulus and density remain constant as the same as those of water, while the figure of merit, i.e., the ratio of the bulk modulus to the shear modulus (B/G) gradually increases due to the decrease of the shear modulus. However, full wave simulations reveal that with the increase of B/G, the acoustic scattering becomes more and more intense, which indicates that the acoustic properties of pentamode metamaterials gradually deviate from those of water. These anomalous acoustic behaviors are proposed to arise from the existence of the bending modes in pentamode microstructures. Our results show that for pentamode metamaterials, the mechanical properties cannot be simply translated to their acoustic properties, and the structural parameters affect the mechanical and acoustic properties in much different ways.

  13. Mechanical and microstructural properties of neutron irradiated Fe-Cr-C alloys

    Energy Technology Data Exchange (ETDEWEB)

    Konstantinovic, M.J.; Renterghem, W. van; Matijasevic, M.; Minov, B.; Lambrecht, M.; Chiapetto, M.; Malerba, L. [Studiecentrum voor Kernenergie/Centre d' Etude de l' Energie Nucleaire (SCK-CEN), Mol (Belgium); Toyama, T. [Institute for Materials Research, Tohoku University, Sendai (Japan)

    2016-11-15

    Defect properties of neutron irradiated Fe-Cr-C alloys and their influence on the mechanical behavior are studied by combining mechanical tests, microstructural examination, and the results of models. It is found that the initial microstructure of these alloys, determined by the Cr and C concentrations, as well as by the thermal treatment, can account for different defect formation and distribution after neutron irradiation. On the basis of these results, a correlation between defect properties and macroscopic mechanical behavior is proposed. (copyright 2016 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  14. Modeling of dynamic mechanical properties of polymer composites reinforced by one dimensional nanofillers

    Science.gov (United States)

    Yu, Y.; Lu, M.; Chen, M. H.; Wang, L. S.; Bu, Z. X.; Song, G.; Sun, L.

    2016-11-01

    Owing to their high aspect ratio, large specific surface area, high axial Young's modulus/strength, and low density, one dimensional carbon nanomaterials can introduce significant change to the mechanical properties of polymer matrices, both static and dynamic. Thus, one of the most important potential applications of carbon nanotubes or nanofibers is to utilize the enhanced dynamic damping properties of polymer nanocomposites for improved vibration, acoustic, and fatigue performances. This study focuses on calculating the nanocomposite energy dissipation under dynamic mechanical loading. A micromechanical model based on quasi-static stick-slip analysis has been developed to quantify the dynamic mechanical properties of the nanocomposites as a function of external strain in the elastic region. Storage and loss moduli are used to characterize such dynamic mechanical behaviors. Influences of nanotube bundling and nanotube alignment on the damping property of composites have been quantified. Simulation results are in good agreement with the reported experimental measurements.

  15. Effect of processing conditions on the mechanical and thermal properties of high-impact polypropylene nanocomposites

    Energy Technology Data Exchange (ETDEWEB)

    Furlan, L.G. [Federal Institute of Rio Grande do Sul, IFRS, Campus Restinga, Estrada Joao Antonio da Silveira, 351, Porto Alegre 91790-400 (Brazil); Ferreira, C.I.; Dal Castel, C.; Santos, K.S.; Mello, A.C.E. [Chemistry Institute, Federal University of Rio Grande do Sul, UFRGS, Av. Bento Goncalves, 9500, Porto Alegre 91501-970 (Brazil); Liberman, S.A.; Oviedo, M.A.S. [Braskem S.A., III Polo Petroquimico, Via Oeste, Lote 5, Triunfo 95853-000 (Brazil); Mauler, R.S., E-mail: mauler@iq.ufrgs.br [Chemistry Institute, Federal University of Rio Grande do Sul, UFRGS, Av. Bento Goncalves, 9500, Porto Alegre 91501-970 (Brazil)

    2011-08-25

    Highlights: {yields} Polypropylene montmorillonite (PP-MMT) produced at different processing conditions. {yields} Polypropylene Nanocomposites with higher increase on impact resistance. {yields} Higher enhancement on mechanical properties. - Abstract: Polypropylene montmorillonite (PP-MMT) nanocomposites have been prepared by using a co-rotating twin screw extruder. The effects of processing conditions at fixed clay content (5 wt%) on polymer properties were investigated by means of transmission electron microscopy (TEM), flexural modulus, izod impact, dynamic mechanical analysis (DMA), and differential scanning calorimetry (DSC). It was noticed that the morphology and the mechanical properties of polypropylene nanocomposites were affected by different screw shear configuration. The results showed that the higher enhancement on mechanical properties was obtained by medium shear intensity profile instead of high configuration. An exceptional increase (maximum of 282%) on impact resistance was observed.

  16. Morphologies and Mechanical Properties of Unsaturated Polyester Resin Modified with TDI

    Institute of Scientific and Technical Information of China (English)

    DUAN Huajun; ZHANG Lianmeng; WANG Jun; YANG Xiaoli

    2008-01-01

    The morphology,mechanical properties of unsaturated polyester(UP)resin modified with TDI were studied via dynamic FT-IR spectra,SEM,DMA and mechanical property testing.Results show that companying with the cured cross-linking reaction of UP resin,TDI can firstly react with UP and produce polyurethane(PU),and then UP and PU form the cross-linking nets together.The impact fracture section morphology of modified UP resin manifested the typical sea-islands structure.Testing of mechanical properties showes that for introducing of PU,the TDI has an obvious effect on the toughness and strength of UP resin.When the ratio of TDI/UP(w/w)was 7.5%,the modified UP resin exhibited the best mechanical properties with

  17. Tensile properties and mechanical heterogeneity of friction stir welded joints of 2014 aluminum alloy

    Institute of Scientific and Technical Information of China (English)

    ZHAO Yan-hua; LIN San-bao; WU Lin; QU Fu-xing

    2005-01-01

    2014 Al alloy of 8mm in thickness was successfully welded by friction stir welding method. The experimental results show that the tensile properties of the joints are significantly affected by the welding parameters. When the weld pitch is 0.25mm/r corresponding to the rotation speed of 400r/min and the welding speed of 100mm/min, the maximum ultimate strength of the joints is 78% that of the base material. For a certain weld joint, different parts possess different mechanical properties. In the three parts of the joint, the upper part is strongest and the middle part is poorest in mechanical properties. The mechanical properties and fracture locations of the joints are dependent on the microstructure variation and micro-hardness distributions of the joints, which attributes to the different thermo-mechanical actions on the different parts of the joints.

  18. Effect of ECAP temperature on microstructure and mechanical properties of Al-Zn-Mg-Cu alloy

    Institute of Scientific and Technical Information of China (English)

    M.H. Shaeri; M. Shaeri; M. Ebrahimi; M.T. Salehi; S. H Seyyedein

    2016-01-01

    The effect of equal channel angular pressing (ECAP) at different temperatures (room temperature, 120, 150 and 180 °C) on microstructure and mechanical properties of Al-7075 solid solution alloy was in-vestigated. Microstructure of the specimens was examined using orientation imaging microscopy, transmission electron microscopy as well as X-ray diffractometer, and mechanical properties were measured by Vickers microhardness and tensile tests. Microstructural investigations showed that after 3 or 4 passes of ECAP, fine grains with average grain sizes in range of 300–1000 nm could be obtained at different ECAP temperatures. Increasing ECAP temperature from 120 to 180 °C caused a decrease in mechanical properties as a result of increasing grains and precipitates sizes, decreasing fraction of high angle boundaries and also transformation ofη′intoηphase, while increasing ECAP temperature from RT to 120 °C leads to an increase in mechanical properties due to the formation of smallη′precipitates. So it can be concluded that ECAP process at 120 °C is the optimum process for attaining maximum mechanical properties. Quantitative estimates of various strengthening mechanisms revealed that the improvement of mechanical properties was mainly attributed to grain refinement strengthening, precipitation strengthening and dislocation strengthening.

  19. Effect of ECAP temperature on microstructure and mechanical properties of Al–Zn–Mg–Cu alloy

    Directory of Open Access Journals (Sweden)

    M.H. Shaeri

    2016-04-01

    Full Text Available The effect of equal channel angular pressing (ECAP at different temperatures (room temperature, 120, 150 and 180 °C on microstructure and mechanical properties of Al-7075 solid solution alloy was investigated. Microstructure of the specimens was examined using orientation imaging microscopy, transmission electron microscopy as well as X-ray diffractometer, and mechanical properties were measured by Vickers microhardness and tensile tests. Microstructural investigations showed that after 3 or 4 passes of ECAP, fine grains with average grain sizes in range of 300–1000 nm could be obtained at different ECAP temperatures. Increasing ECAP temperature from 120 to 180 °C caused a decrease in mechanical properties as a result of increasing grains and precipitates sizes, decreasing fraction of high angle boundaries and also transformation of η′ into η phase, while increasing ECAP temperature from RT to 120 °C leads to an increase in mechanical properties due to the formation of small η′ precipitates. So it can be concluded that ECAP process at 120 °C is the optimum process for attaining maximum mechanical properties. Quantitative estimates of various strengthening mechanisms revealed that the improvement of mechanical properties was mainly attributed to grain refinement strengthening, precipitation strengthening and dislocation strengthening.

  20. Effect of Bi on graphite morphology and mechanical properties of heavy section ductile cast iron

    Directory of Open Access Journals (Sweden)

    Song Liang

    2014-03-01

    Full Text Available To improve the mechanical properties of heavy section ductile cast iron, bismuth (Bi was introduced into the iron. Five castings with different Bi content from 0 to 0.014 wt.% were prepared; and four positions in the casting from the edge to the center, with different solidification cooling rates, were chosen for microstructure observation and mechanical properties test. The effect of the Bi content on the graphite morphology and mechanical properties of heavy section ductile cast iron were investigated. Results show that the tensile strength, elongation and impact toughness at different positions in the five castings decrease with a decrease in cooling rate. With an increase in Bi content, the graphite morphology and the mechanical properties at the same position are improved, and the improvement of mechanical properties is obvious when the Bi content is no higher than 0.011wt.%. But when the Bi content is further increased to 0.014wt.%, the improvement of mechanical properties is not obvious due to the increase of chunky graphite number and the aggregation of chunky graphite. With an increase in Bi content, the tensile fracture mechanism is changed from brittle to mixture ductile-brittle fracture.

  1. Tensile Mechanical Properties and Strengthening Mechanism of Hybrid Carbon Nanotube and Silicon Carbide Nanoparticle-Reinforced Magnesium Alloy Composites

    National Research Council Canada - National Science Library

    Zhou, Xia; Su, Depeng; Wu, Chengwei; Liu, Liming

    2012-01-01

    .... The results showed that grains of the matrix in the AZ91/(CNT + SiC) composites were obviously refined after adding hybrid CNTs and SiC nanoparticles to the AZ91 alloy, and the room-temperature mechanical properties of AZ91/(CNT + SiC...

  2. How Tissue Mechanical Properties Affect Enteric Neural Crest Cell Migration.

    Science.gov (United States)

    Chevalier, N R; Gazguez, E; Bidault, L; Guilbert, T; Vias, C; Vian, E; Watanabe, Y; Muller, L; Germain, S; Bondurand, N; Dufour, S; Fleury, V

    2016-02-18

    Neural crest cells (NCCs) are a population of multipotent cells that migrate extensively during vertebrate development. Alterations to neural crest ontogenesis cause several diseases, including cancers and congenital defects, such as Hirschprung disease, which results from incomplete colonization of the colon by enteric NCCs (ENCCs). We investigated the influence of the stiffness and structure of the environment on ENCC migration in vitro and during colonization of the gastrointestinal tract in chicken and mouse embryos. We showed using tensile stretching and atomic force microscopy (AFM) that the mesenchyme of the gut was initially soft but gradually stiffened during the period of ENCC colonization. Second-harmonic generation (SHG) microscopy revealed that this stiffening was associated with a gradual organization and enrichment of collagen fibers in the developing gut. Ex-vivo 2D cell migration assays showed that ENCCs migrated on substrates with very low levels of stiffness. In 3D collagen gels, the speed of the ENCC migratory front decreased with increasing gel stiffness, whereas no correlation was found between porosity and ENCC migration behavior. Metalloprotease inhibition experiments showed that ENCCs actively degraded collagen in order to progress. These results shed light on the role of the mechanical properties of tissues in ENCC migration during development.

  3. Mechanical properties of gangue-containing aluminosilicate based cementitious materials

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    High performance aluminosilicate based cementitious materials were produced using calcined gangue as one of the major raw materials.The gangue was calcined at 500℃.The main constituent was calcined gangue, fly ash and slag, while alkali-silicate solutions were used as the diagenetic agent.The structure of gangue-containing aluminosilicate based cementitious materials was studied by the methods of IR, NMR and SEM.The results show that the mechanical properties are affected by the mass ratio between the gangue, slag and fly ash, the kind of activator and additional salt.For 28-day curing time, the compressive strength of the sample with a mass proportion of 2:1:1 (gangue: slag: fly ash) is 58.9 MPa, while the compressive strength of the sample containing 80wt%gangue can still be up to 52.3 MPa.The larger K+ favors the formation of large silicate oligomers with which Al(OH)4- prefers to bind.Therefore, in Na-K compounding activator solutions more oligomers exist which result in a stronger compressive strength of aluminosilicate-based cementitious materials than in the case of Na-containing activator.The reasons for this were found through IR and NMR analysis.Glauber's salt reduces the 3-day compressive strength of the paste, but increases its 7-day and 28-day compressive strengths.

  4. Development of Mechanical and Failure Properties in Sheep Cerebral Arteries.

    Science.gov (United States)

    Nye, Kevin S; Converse, Matthew I; Dahl, Mar Janna; Albertine, Kurt H; Monson, Kenneth L

    2017-04-01

    Traumatic brain injury (TBI) is a devastating problem for people of all ages, but the nature of the response to such injury is often different in children than in adults. Cerebral vessel damage and dysfunction are common following TBI, but age-dependent, large-deformation vessel response has not been characterized. Our objective was to investigate the mechanical properties of cerebral arteries as a function of development. Sheep middle cerebral arteries from four age groups (fetal, newborn, juvenile, and adult) were subjected to biaxial loading around physiological conditions and then to failure in the axial direction. Results show little difference among age groups under physiological loading conditions, but response varied significantly with age in response to large axial deformation. Vessels from all age groups reached the same ultimate stretch level, but the amount of stress carried at a given level of stretch increased significantly with age through the developmental period (fetal to juvenile). Our results are the first to identify changes in cerebral vessel response to large deformations with age and may lead to new insights regarding differences in response to TBI with age.

  5. Mechanical Properties of Gas Shale During Drilling Operations

    Science.gov (United States)

    Yan, Chuanliang; Deng, Jingen; Cheng, Yuanfang; Li, Menglai; Feng, Yongcun; Li, Xiaorong

    2017-07-01

    The mechanical properties of gas shale significantly affect the designs of drilling, completion, and hydraulic fracturing treatments. In this paper, the microstructure characteristics of gas shale from southern China containing up to 45.1% clay were analyzed using a scanning electron microscope. The gas shale samples feature strongly anisotropic characteristics and well-developed bedding planes. Their strength is controlled by the strength of both the matrix and the bedding planes. Conventional triaxial tests and direct shear tests are further used to study the chemical effects of drilling fluids on the strength of shale matrix and bedding planes, respectively. The results show that the drilling fluid has a much larger impact on the strength of the bedding plane than that of the shale matrix. The impact of water-based mud (WBM) is much larger compared with oil-based mud. Furthermore, the borehole collapse pressure of shale gas wells considering the effects of drilling fluids are analyzed. The results show that the collapse pressure increases gradually with the increase of drilling time, especially for WBM.

  6. Thermal and Mechanical Properties of Poly(butylene succinate Films Reinforced with Silica

    Directory of Open Access Journals (Sweden)

    Sangviroon Nanthaporn

    2015-01-01

    Full Text Available In recent year, bioplastics have become more popular resulting from the growing concerns on environmental issues and the rising fossil fuel price. However, their applications were limited by its mechanical and thermal properties. The aim of this research is thus to improve mechanical and thermal properties of PBS bioplastic films by reinforcing with silica. Due to the poor interfacial interaction between the PBS matrix and silica, glycidyl methacrylate grafted poly(butylene succinate (PBS-g-GMA was used as a compatibilizer in order to improve the interaction between bioplastic films and filler. PBS-g-GMA was prepared in a twin-screw extruder and analyzed by the FTIR spectrometer. PBS and silica were then mixed in a twin-screw extruder and processed into films by a chill-roll cast extruder. The effects of silica loading on thermal and mechanical properties of the prepared bioplastic films were investigated. It was found that the mechanical properties of PBS/silica composite films were improved when 1%wt of silica was added. However, the mechanical properties decreased with increasing silica loading due to the agglomeration of silica particles. The results also show that the silica/PBS films with PBS-g-GMA possessed improved mechanical properties over the films without the compatibilizer.

  7. Effect of entanglements on mechanical properties of glassy polymers

    Science.gov (United States)

    Hoy, Robert Scott

    Glass forming polymers are of great industrial importance and scientific interest because of their unique mechanical properties, which arise from the connectivity and random-walk-like structure of the constituent chains. In this thesis I study the relation of entanglements to the mechanical properties of model polymer glasses and brushes using molecular dynamics simulations. We perform extensive studies of glassy strain hardening, which stabilizes polymers against strain localization and fracture. Fundamental inconsistencies in existing entropic models of strain hardening imply that our understanding of its microscopic origins is far from complete. The dependence of stress on strain and entanglement density is consistent with experiment and entropic models. However, many of the assumptions of these models are totally inconsistent with our simulation results. The dependence on temperature, rate and interaction strength can be understood as reflecting changes in the plastic flow stress rather than a network entropy. A substantial energetic contribution to the stress rises rapidly as segments between entanglements are pulled taut. The thermal component of stress is less sensitive to entanglements, mostly irreversible, and directly related to the rate of local plastic arrangements. The deformation of the entanglement network is not affine to the macroscopic stretch. Entangled and unentangled chains show the same strain hardening when plotted against the microscopic chain orientation rather than the macroscopic strain. The entropic back stress responsible for shape recovery arises from chain orientation rather than entanglement. We also present some other results unrelated to strain hardening. We analyze the entanglement of polymer brushes embedded in long-chain melts and in implicit good and theta solvents. The melt-embedded brushes are more self-entangled than those in the solvents. The degree of self-entanglement of the brushes in the solvents follows a simple

  8. Structure-mechanics property relationship of waste derived biochars.

    Science.gov (United States)

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

    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 60min residence time was found to have the highest hardness and elastic modulus of 4.29 and 25.01GPa, respectively. It was shown that a combination of higher heat treatment (≥500°C) temperature and longer residence time (~60min) 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.

  9. Chemical and Mechanical Alteration of Fractures: Micro-Scale Simulations and Comparison to Experimental Results

    Science.gov (United States)

    Ameli, P.; Detwiler, R. L.; Elkhoury, J. E.; Morris, J. P.

    2012-12-01

    Fractures are often the main pathways for subsurface fluid flow especially in rocks with low matrix porosity. Therefore, the hydro-mechanical properties of fractures are of fundamental concern for subsurface CO2 sequestration, enhanced geothermal energy production, enhanced oil recovery, and nuclear waste disposal. Chemical and mechanical stresses induced during these applications may lead to significant alteration of the hydro-mechanical properties of fractures. Laboratory experiments aimed at understanding the chemo-hydro-mechanical response of fractures have shown a range of results that contradict simple conceptual models. For example, under conditions favoring mineral dissolution, where one would expect an overall increase in permeability and fracture aperture, permeability increases under some conditions and decreases under others. Recent experiments have attempted to link these core-scale observations to the relevant small-scale processes occurring within fractures. Results suggest that the loss of mechanical strength in asperities due to chemical alteration may cause non-uniform deformation and alteration of fracture apertures. However, it remains difficult to directly measure the coupled chemical and mechanical processes that lead to alteration of contacting fracture surfaces, which challenges our ability to predict the long-term evolution of the hydro-mechanical properties of fractures. Here, we present a computational model that uses micro-scale surface roughness and explicitly couples dissolution and elastic deformation to calculate local alterations in fracture aperture under chemical and mechanical stresses. Chemical alteration of the fracture surfaces is modeled using a depth-averaged algorithm of fracture flow and reactive transport. Then, we deform the resulting altered fracture-surfaces using an algorithm that calculates the elastic deformation. Nonuniform dissolution may cause the location of the resultant force between the two contacting

  10. Mechanical properties of fibroblasts depend on level of cancer transformation.

    Science.gov (United States)

    Efremov, Yu M; Lomakina, M E; Bagrov, D V; Makhnovskiy, P I; Alexandrova, A Y; Kirpichnikov, M P; Shaitan, K V

    2014-05-01

    Recently, it was revealed that tumor cells are significantly softer than normal cells. Although this phenomenon is well known, it is connected with many questions which are still unanswered. Among these questions are the molecular mechanisms which cause the change in stiffness and the correlation between cell mechanical properties and their metastatic potential. We studied mechanical properties of cells with different levels of cancer transformation. Transformed cells in three systems with different transformation types (monooncogenic N-RAS, viral and cells of tumor origin) were characterized according to their morphology, actin cytoskeleton and focal adhesion organization. Transformation led to reduction of cell spreading and thus decreasing the cell area, disorganization of actin cytoskeleton, lack of actin stress fibers and decline in the number and size of focal adhesions. These alterations manifested in a varying degree depending on type of transformation. Force spectroscopy by atomic force microscopy with spherical probes was carried out to measure the Young's modulus of cells. In all cases the Young's moduli were fitted well by log-normal distribution. All the transformed cell lines were found to be 40-80% softer than the corresponding normal ones. For the cell system with a low level of transformation the difference in stiffness was less pronounced than for the two other systems. This suggests that cell mechanical properties change upon transformation, and acquisition of invasive capabilities is accompanied by significant softening.

  11. IMPROVING THE MECHANICAL PROPERTIES OF COPPER ALLOYS BY THERMO-MECHANICAL PROCESSING

    Institute of Scientific and Technical Information of China (English)

    M.C.Somani; L.P.Karjalainen

    2004-01-01

    Systematic physical simulation of thermo-mechanical processing routes has been applied on a Gleeble 1500 simulator to four copper alloys(mass %)Cu-0.57Co-0.32Si,Cu-0.55Cr-0.065P,Cu-0.22Zr-0.035Si and Cu-1.01Ni-0.43Si aimed at clarifying the influences of processing conditions on their final properties,strength and electrical conductivity.Flow curves were determined over wide temperature and strain rate ranges.Hardness was used as a measure of the strength level achieved.High hardness was obtained as using equal amounts(strains 0.5)of cold deformation before and after the precipitation annealing stage.The maximum values achieved for the Cu-Co-Si,Cu-Cr-P,Cu-Zr-Si and Cu-Ni-Si alloys were 190,165,178 and 193 HV5,respectively.A thermo-mechanical schedule involving the hot deformation-ageing-cold deformation stages showed even better results for the Cu-Zr-Si alloy.Consequently,the processing routes were designed based on simulation test results and wires of 5 and 2mm in diameters have been successfully processed in the industrial scale.

  12. Influence of solution annealing on microstructure and mechanical properties of Maraging 300 steel

    Energy Technology Data Exchange (ETDEWEB)

    Lima Filho, Venceslau Xavier; Barros, Isabel Ferreira; Abreu, Hamilton Ferreira Gomes de, E-mail: venceslau@ifce.edu.br [Universidade Federal do Ceara (UFC), Fortaleza, CE (Brazil). Departamento de Engenharia Metalurgica e Materiais. Laboratorio de Caracterizacao de Materiais, Metalurgia Fisica e Grupo de Pesquisa de Transformacao de Fase

    2017-01-15

    Maraging 300 belongs to a family of metallic materials with extremely high mechanical strength and good toughness. Some works have been published about aging temperatures that improve ultimate strength resistance with acceptable toughness levels in this steel family, where the prior austenite grain size obtained by different solution annealing temperature influence in the final mechanical properties. Solution annealing temperatures ranging from 860 °C to 1150 deg C and were kept constant until the aging temperature. These treatments were used in order to investigate their influence on the microstructure and mechanical properties of maraging steel 300, especially with regard to toughness. The characterization of the microstructure was performed by optical microscopy, scanning electron microscope (SEM) and X-ray diffraction (XRD). Mechanical properties were evaluated by Rockwell C hardness and Charpy impact tests. The results showed that there is a temperature range where one can get some improvement in toughness without a large loss of mechanical strength. (author)

  13. Molecular Structures and Mechanical Properties of Microbe Rapid Coagulation Natural Rubber

    Institute of Scientific and Technical Information of China (English)

    LIANG Yue; HUANG Mao-Fang; ZENG Zong-Qiang

    2011-01-01

    In this work,molecular structures,dynamic mechanical properties and glass transition temperatures of microbe coagulated natural rubber(NR) samples were analyzed by using pyrolysis gas chromatography-mass spectrometry(py-GC/MS),rubber process analyzer(RPA) and dynamic mechanical thermal analysis(DMA).And the cross-linked network structures and mechanical properties of the corresponding NR vulcanizates were further determined by using nuclear magnetic resonance(NMR) crosslink density spectrometer(XLDS-15) and universal testing machines.The results show that NR raw rubber produced by rapidly coagulated with microorganism exhibits a simple molecular structure composition and good dynamic mechanical properties,and the corresponding NR vulcanizates possess the aggregation structure of high cross-linked density,a high glass transition temperature of-61.5 ℃ and high mechanical properties(tensile strength reaches 25.2 MPa),as compared with that coagulated with acetic acid.

  14. Temperature Effect on Mechanical Properties and Damage Identification of Concrete Structure

    Directory of Open Access Journals (Sweden)

    Yubo Jiao

    2014-01-01

    Full Text Available Static and dynamic mechanical properties of concrete are affected by temperature effect in practice. Therefore, it is necessary to investigate the corresponding influence law and mechanism. This paper demonstrates the variation of mechanical properties of concrete at temperatures from −20°C to 60°C. Temperature effects on cube compressive strength, splitting tensile strength, prism compressive strength, modulus of elasticity, and frequency are conducted and discussed. The results indicate that static mechanical properties such as compressive strength (cube and prism, splitting tensile strength, and modulus of elasticity have highly linear negative correlation with temperature; this law is also applied to the first order frequency of concrete slab. The coupling effect of temperature and damage on change rate of frequency reveals that temperature effect cannot be ignored in damage identification of structure. Mechanism analysis shows that variation of elastic modulus of concrete caused by temperature is the primary reason for the change of frequency.

  15. Chemical Modification Effect on the Mechanical Properties of Coir Fiber

    Directory of Open Access Journals (Sweden)

    Samia Sultana Mir

    2012-04-01

    Full Text Available Natural fiber has a vital role as a reinforcing agent due to its renewable, low cost, biodegradable, less abrasive and eco-friendly nature. Whereas synthetic fibers like glass, boron, carbon, metallic, ceramic and inorganic fibers are expensive and not eco-friendly. Coir is one of the natural fibers easily available in Bangladesh and cheap. It is derived from the husk of the coconut (Cocos nucifera. Coir has one of the highest concentrations of lignin, which makes it stronger. In recent years, wide range of research has been carried out on fiber reinforced polymer composites [4-13].The aim of the present research is to characterize brown single coir fiber for manufacturing polymer composites reinforced with characterized fibers. Adhesion between the fiber and polymer is one of factors affecting the strength of manufactured composites. In order to increase the adhesion, the coir fiber was chemically treated separately in single stage (with Cr2(SO43•12(H2O and double stages (with CrSO4 and NaHCO3. Both the raw and treated fibers were characterized by tensile testing, Fourier transform infrared (FTIR spectroscopic analysis, scanning electron microscopic analysis. The result showed that the Young’s modulus increased, while tensile strength and strain to failure decreased with increase in span length. Tensile properties of chemically treated coir fiber was found higher than raw coir fiber, while the double stage treated coir fiber had better mechanical properties compared to the single stage treated coir fiber. Scanning electron micrographs showed rougher surface in case of the raw coir fiber. The surface was found clean and smooth in case of the treated coir fiber. Thus the performance of coir fiber composites in industrial application can be improved by chemical treatment.

  16. Exterior difference systems and invariance properties of discrete mechanics

    Energy Technology Data Exchange (ETDEWEB)

    Xie Zheng; Xie Duanqiang; Li Hongbo [Center of Mathematical Sciences, Zhejiang University, Zhejiang 310027 (China); Key Laboratory of Mathematics Mechanization, Chinese Academy of Sciences, Beijing 100080 (China)], E-mail: lenozhengxie@yahoo.com.cn

    2008-06-27

    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.

  17. The Structure, Functions, and Mechanical Properties of Keratin

    Science.gov (United States)

    McKittrick, J.; Chen, P.-Y.; Bodde, S. G.; Yang, W.; Novitskaya, E. E.; Meyers, M. A.

    2012-04-01

    Keratin is one of the most important structural proteins in nature and is widely found in the integument in vertebrates. It is classified into two types: α-helices and β-pleated sheets. Keratinized materials can be considered as fiber-reinforced composites consisting of crystalline intermediate filaments embedded in an amorphous protein matrix. They have a wide variety of morphologies and properties depending on different functions. Here, we review selected keratin-based materials, such as skin, hair, wool, quill, horn, hoof, feather, and beak, focusing on the structure-mechanical property-function relationships and finally give some insights on bioinspired composite design based on keratinized materials.

  18. Mechanical Properties of Wood Flour Reinforced High Density Polyethylene Composites with Basalt Fibers

    Directory of Open Access Journals (Sweden)

    Guojun LU

    2014-12-01

    Full Text Available Basalt fibers (BFs were surface-treated with a vinyl triethoxy silane coupling agent to improve the mechanical properties of wood fiber-reinforced high density polyethylene (HDPE composites. Basalt fibers were characterized with SEM and FT-IR. The effects of the basalt fiber content and apparent morphology on the mechanical properties of the hybrid composites were investigated in this paper. The results show that the BF coated with the vinyl triethoxy silane coupling agent resulted in an improvement in mechanical properties due to the increased interfacial compatibility between the BF and HDPE. The flexural strength and impact properties significantly increased with 4 wt.% modified basalt fibers. DOI: http://dx.doi.org/10.5755/j01.ms.20.4.6441

  19. Remanence Properties and Magnetization Reversal Mechanism of Fe Nanowire Arrays

    Institute of Scientific and Technical Information of China (English)

    WANG Jian-Bo; LIU Qing-Fang; XUE De-Sheng; LI Fa-Shen

    2004-01-01

    @@ Remanence properties and magnetization reversal mechanism of Fe nanowire arrays with diameters 16 nm and130nm are studied. Isothermal remanent magnetization curves show that the contribution of irreversible magnetization decreases when the diameter changes from 16nm to 130nm. The remanence coercivities of these nanowires obtained in dc-demagnetization curve are about 2400 Oe and 800 Oe, respectively. The magnetization reversal mechanism is different in these two samples. For the nanowire array with diameter 16nm, both the nucleation and the pinning have effects on magnetization reversal mechanism, and the pinning field (about 2500Oe) is larger than the nucleation field (about 2200 Oe). However, for the nanowire array with diameter 130nm,the magnetization reversal mechanism is dominated by the pinning effect of domain walls.

  20. Structural and mechanical properties of mandibular condylar bone.

    Science.gov (United States)

    van Eijden, T M G J; van der Helm, P N; van Ruijven, L J; Mulder, L

    2006-01-01

    The trabecular bone of the mandibular condyle is structurally anisotropic and heterogeneous. We hypothesized that its apparent elastic moduli are also anisotropic and heterogeneous, and depend on trabecular density and orientation. Eleven condyles were scanned with a micro-CT system. Volumes of interest were selected for the construction of finite element models. We simulated compressive and shear tests to determine the principal mechanical directions and the apparent elastic moduli. Compressive moduli were relatively large in directions acting in the sagittal plane, and small in the mediolateral direction. The degree of mechanical anisotropy ranged from 4.7 to 10.8. Shear moduli were largest in the sagittal plane and smallest in the transverse plane. The magnitudes of the moduli varied with the condylar region and were proportional to the bone volume fraction. Furthermore, principal mechanical direction correlated significantly with principal structural direction. It was concluded that variation in trabecular structure coincides with variation in apparent mechanical properties.

  1. Bifurcation property and persistence of configurations for parallel mechanisms

    Institute of Scientific and Technical Information of China (English)

    王玉新; 王仪明; 刘学深

    2003-01-01

    The configuration of parallel mechanisms at the singularity position is uncertain. How to control the mechanism through the singularity position with a given configuration is one of the key problems of the robot controlling. In this paper the bifurcation property and persistence of configurations at the singularity position is investigated for 3-DOF parallel mechanisms. The dimension of the bifurcation equations is reduced by Liapunov-Schmidt reduction method. According to the strong equivalence condition, the normal form which is consistent with the bifurcation condition of the original equation is selected. Through universal unfolding of the bifurcation equation, the influences of the disturbance factors, such as the influence of length of the input component on the configuration persistence at the bifurcation position, are analyzed. Using this method we can obtain the bifurcation curve in which the configuration will be held when the mechanism passes through the singularity position. Therefore, the configuration is under control in this way.

  2. EVALUATION OF THE PHYSICAL AND MECHANICAL PROPERTIES OF PARTICLEBOARD MADE FROM GIANT REED (ARUNDO DONAX L.

    Directory of Open Access Journals (Sweden)

    Manuel Ferrández-Villena García

    2011-02-01

    Full Text Available Single-layer experimental particleboards were made from various sizes of Arundo donax particles bonded with urea formaldehyde resin. The experimental panels were tested for their mechanical strength including modulus of rupture (MOR, modulus of elasticity (MOE, internal bonding (IB, screw holding strength (SH, and physical properties (density, moisture content, thickness swelling (TS, and water absorption (WA according to the procedures defined by European Union (EN Standards. The overall results showed that most panels exceeded the EN Standards for MOE, MOR, and IB. The mechanical properties of the particleboard were enhanced as the density increased. Particle size was found to have a profound effect on the board properties.

  3. Effect of quenching techniques on the mechanical properties of low carbon structural steel

    Directory of Open Access Journals (Sweden)

    K. Miernik

    2010-07-01

    Full Text Available The paper presents the results of the impact of incomplete quenching technique on the mechanical properties of low carbon structural steel.Significant influence of the heating method to the α + γ field was observed on the strength and plasticity after hardening process. The best combination of mechanical properties was obtained for the 3th technique consisting of pre-heating the material to the austenite field, next cooling to the appropriate temperature in the α + γ and hardening from that dual phase region. The high level of toughness with relatively high strength were observed, compared to the properties obtained for the two other ways to quench annealing (incomplete hardening.

  4. Mechanical properties correlation to processing parameters for advanced alumina based refractories

    Directory of Open Access Journals (Sweden)

    Dimitrijević Marija M.

    2012-01-01

    Full Text Available Alumina based refractories are usually used in metallurgical furnaces and their thermal shock resistance is of great importance. In order to improve thermal shock resistance and mechanical properties of alumina based refractories short ceramic fibers were added to the material. SEM technique was used to compare the microstructure of specimens and the observed images gave the porosity and morphological characteristics of pores in the specimens. Standard compression test was used to determine the modulus of elasticity and compression strength. Results obtained from thermal shock testing and mechanical properties measurements were used to establish regression models that correlated specimen properties to process parameters.

  5. Metal-ceramic materials. Study and prediction of effective mechanical properties

    Science.gov (United States)

    Karakulov, Valerii V.; Smolin, Igor Yu.

    2016-08-01

    Mechanical behavior of stochastic metal-ceramic composite materials was numerically simulated on mesoscopic scale level. Deformation of mesoscopic volumes of composites, whose structure consists of a metal matrix and randomly distributed ceramic inclusions, was numerically simulated. The results of the numerical simulation were used for evaluation of the effective elastic and strength properties of metal-ceramic materials with different parameters of the structure. The values of the effective mechanical properties of investigated materials were obtained, and the character of the dependence of the effective elastic and strength properties on the structure parameters of composites was determined.

  6. Results of Monitoring at Olkiluoto in 2010. Rock Mechanics

    Energy Technology Data Exchange (ETDEWEB)

    Lahti, M. (ed.); Siren, T.

    2011-12-15

    The rock mechanical monitoring at Olkiluoto concentrates on the assessment of potential tectonic movements and stability of the bedrock. The construction of ONKALO is not expected to induce large-scale movements of the rock blocks or affect the rate of isostatic uplift but the evaluation of any tectonic events is important for the safety assessment. The monitoring consists of seismic measurements, GPS measurements and precise levelling campaigns at Olkiluoto and vicinity and extensometer and convergence measurements carried out in ONKALO. Posiva established a local seismic network of six stations on the island of Olkiluoto in 2002. After that the number of seismic stations has increased gradually. In 2010 the permanent seismic network consists of 15 seismic stations and 20 triaxial sensors. The purpose of the microearthquake measurements at Olkiluoto is to improve understanding of the structure, behaviour and long term stability of the bedrock. The investigation area includes two target areas. The larger target area, called seismic semiregional area, covers the Olkiluoto Island and its surroundings. The purpose is to monitor explosions and tectonic earthquakes in regional scale inside that area. The smaller target area is called the seismic ONKALO block, which is a 2 km *2 km *2 km cube surrounding the ONKALO. It is assumed that all the expected excavation induced events occur within this volume. At the moment the seismic ONKALO block includes ten seismic stations. An additional task of monitoring is related to safeguarding of the ONKALO. This report gives the results of microseismic monitoring during 2010.

  7. Effect of epoxy resin properties on the mechanical properties of carbon fiber/epoxy resin composites

    Energy Technology Data Exchange (ETDEWEB)

    He, Hong-Wei; Gao, Feng [Taiyuan Univ. of Technology (China). College of Materials Science and Engineering; Taiyuan Univ. of Technology (China). Key Laboratory of Interface Science and Engineering in Advanced Materials; Li, Kai-Xi [Chinese Academy of Sciences, Taiyuan, Shanxi (China). Key Laboratory of Carbon Materials

    2013-09-15

    Three kinds of epoxy resins, i.e. tetraglycidyl diaminodiphenyl methane (AG80), difunctional diglycidyl ether of bisphenol-A (E51) and novolac type epoxy resin (F46) were selected as matrices for carbon fiber/epoxy composites. The objective of this work is to study the mechanical properties of fiber/epoxy composites by using these three kinds of epoxy resins with different physical and chemical performance. The results show that the composites fabricated with AG80 present the best stiffness and the composites prepared with E5 1have the best toughness. The stiffness and toughness of the composites prepared with F46 are middle values located between those for AG80/epoxy and E51/epoxy composites. Thus, the mixed epoxy resin is a promising approach for industrial production. (orig.)

  8. Simulative Calculation of Mechanical Property, Binding Energy and Detonation Property of TATB/Fluorine-polymer PBX

    Institute of Scientific and Technical Information of China (English)

    MA, Xiu-Fang; XIAO, Ji-Jun; HUANG, Hui; JU, Xue-Hai; LI, Jin-Shan; XIAO, He-Ming

    2006-01-01

    Molecular dynamics (MD) method was used to simulate 1,3,5-triamino-2,4,6-trinitrobenzene (TATB) coated with fluorine containing polymers. The mechanical properties and binding energies of PBXs were obtained. It was found that when the number of chain monomers of fluorine containing polymers was the same, the elasticity of TATB/F2314 was increased more greatly than others and the binding energy of TATB/F2311 was the largest among four PBXs. Detonation heat and velocity of such four PBXs were calculated according to theoretical and empirical formulas. The results show that the order of detonation heat is TATB>TATB/PVDF>TATB/F2311 >TATB/F2314>TATB/PCTFE while the order of detonation velocity is TATB/PVDF<TATB/F2311 <TATB/F2314<TATB/PCTFE<TATB.

  9. Nanoclay reinforced thermoplastic toughened epoxy hybrid syntactic foam: Surface morphology, mechanical and thermo mechanical properties

    Energy Technology Data Exchange (ETDEWEB)

    Asif, A. [Propellants and Special Chemicals Group, Propellants Polymers Chemicals and Materials Entity, Vikram Sarabhai Space Centre, Trivandrum 695022 (India); Rao, V. Lakshmana, E-mail: rao_vl@yahoo.co.in [Propellants and Special Chemicals Group, Propellants Polymers Chemicals and Materials Entity, Vikram Sarabhai Space Centre, Trivandrum 695022 (India); Ninan, K.N. [Propellants and Special Chemicals Group, Propellants Polymers Chemicals and Materials Entity, Vikram Sarabhai Space Centre, Trivandrum 695022 (India)

    2010-09-15

    Epoxy hybrid syntactic foams were prepared with diglycidyl ether of bisphenol A (DGEBA) epoxy resin, diamino diphenyl sulfone (DDS), hydroxyl terminated polyether ether ketone having pendant methyl group (PEEKMOH), microballoon and nanoclay. The density of the foam was maintained between 0.6 and 0.72 g/cc for all compositions. Fracture toughness, tensile, flexural and compressive properties of the foam were evaluated with respect to clay and PEEKMOH concentrations. Morphology by X-ray diffraction revealed that the clay particles within the epoxy resin were intercalated for all the compositions of the syntactic foam. Fracture toughness and mechanical properties of the syntactic foam were significantly improved by the addition of nanoclay. A further enhancement in fracture toughness and mechanical properties was observed by the addition of PEEKMOH. The hybrid epoxy syntactic foam thus prepared exhibited 58%, 77% and 38% improvement in compressive strength, percentage elongation and fracture toughness, respectively, compared to the neat epoxy syntactic foam. The specific mechanical properties were found to be higher for the epoxy hybrid syntactic foam containing 3 wt% nanoclay and 3 wt% of PEEKMOH combination. The storage and loss modulus of the syntactic foam were also increased by the addition of nanoclay and PEEKMOH. A marginal improvement in T{sub g} was observed with clay incorporated syntactic foam. SEM analysis revealed that increased microcracking, crack path deflection, matrix deformation, plastic deformation, rupture of microballoons and debonded microspheres influencing on fracture toughness and mechanical properties of epoxy hybrid syntactic foam.

  10. Does pH influence soil hydro-mechanical properties?

    Science.gov (United States)

    Chaplain, V.; Défossez, P.; Delarue, G.; Dexter, A. R.; Richard, G.; Tessier, D.

    2009-04-01

    Does pH influence soil hydro-mechanical properties ? V. Chaplain1, P. Défossez2, G. Delarue1, A.R. Dexter3, G. Richard3 and D. Tessier1. 1 UR INRA PESSAC RD 10, F-78026 Versailles cedex 2 UMR INRA/URCA FARE, 2 Esplanade Roland Garros, BP 224 F-51686 Reims cedex 2 3 UR INRA Sols 2163 Avenue de la Pomme de Pin - CS 40001 ARDON F-45075 Orléans Cedex 2 Corresponding author : chaplain@versailles.inra.fr Structure of soils and its dynamic, physico-chemistry of the interface are of a great importance in the fate of organic pollutants because it governs the accessibility of pollutants to micro-organisms. The soil structure of soils is related to physical parameters (texture, density, water content) but the physico-chemical properties of the interface is not considered. In this study we performed hydro-mechanical measurements on soil samples taken from the 42-plot long-term experiment in Versailles. Indeed six plots were selected to cover a large range of pH values from acid (3.5) to alkaline (8.2) due to the repeated application of fertilizers. Soils were taken in the 0-20 cm and in the 30-35 cm layer out of the ploughed zone. All soils had similar texture and composition with low organic carbon. Therefore pH changes the surface charges and hydrophobicity that are implied in aggregation process. The two layers had the same pH values. The precompression stress Pc and the compression index Cc were derived from confined compression tests performed on remoulded soil samples (density 1.45 g/cm3) at saturation. Results shows that the precompression stress increased at pH lower than 4. In acid case, precompression stress was higher in subsoil. This increase of Pc was attributed to the hydrophobicity due in part to the condensation of charges probably sensitive to the humectation/dessication processes.

  11. INFLUENCE OF COLD ROLLING REDUCTION ON MICROSTRUCTURE AND MECHANICAL PROPERTIES OF TWIP STEEL

    Institute of Scientific and Technical Information of China (English)

    Z.L. Mi; D. Tang; Y.J. Dai; H.Q. Wang; S.S. Li

    2007-01-01

    The influence of cold rolling reduction on microstructure and mechanical properties of the TWIP (ttwinning induced plasticity) steel was investigated. The results indicated that the steel had better comprehensive mechanical properties when cold rolling reduction was about 65.0% and the annealing temperature was 1000℃. The tensile strength of the steel is about 640MPa and the yield strength is higher than 255MPa, while the elongation is above 82%. The microstructure is composed of austenitic matrix and annealing twins at room temperature, at the same time, a significant amount of annealing twins and stacking faults are observed by transmission electron microscopy (TEM). Mechanical twins play a dominant role during deformation, and result in excellent mechanical properties.

  12. Correlation of surface treatment, dispersion and mechanical properties of HDPE/CNT nanocomposites

    Science.gov (United States)

    Ferreira, Filipe V.; Francisco, Wesley; Menezes, Beatriz R. C.; Brito, Felipe S.; Coutinho, André S.; Cividanes, Luciana S.; Coutinho, Aparecido R.; Thim, Gilmar P.

    2016-12-01

    The effect of carbon nanotube treatment on the mechanical property of polyethylene/carbon nanotube composite (HDPE/CNT) was investigated. CNTs were initially treated with HCl and then with H2SO4/HNO3. Nanocomposites reinforced with untreated and treated CNTs were prepared by a mechanical mixture of the molten polymer. The results demonstrated a correlation among the surface treatment, dispersion and mechanical properties of HDPE/CNT composites. Raman spectroscopy and TGA analysis showed that both acid treatments removed efficiently amorphous carbon and residual metal catalysts of CNTs. However, these treatments not only removed impurities, they also decreased the crystallinity degree of CNTs due to the addition of oxygenated functional groups to the CNTs walls, as observed by XPS analysis. SEM micrographs revealed that the functional groups improved the CNTs dispersion in the polymeric matrix, resulting in an improvement of the mechanical properties of nanocomposites.

  13. Properties of Syntactic Foam for Simulation of Mechanical Insults.

    Energy Technology Data Exchange (ETDEWEB)

    Hubbard, Neal Benson [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Haulenbeek, Kimberly K. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Spletzer, Matthew A. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Ortiz, Lyndsy [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

    2017-02-01

    Syntactic foam encapsulation protects sensitive components. The energy mitigated by the foam is calculated with numerical simulations. The properties of a syntactic foam consisting of a mixture of an epoxy-rubber adduct and glass microballoons are obtained from published literature and test results. The conditions and outcomes of the tests are discussed. The method for converting published properties and test results to input for finite element models is described. Simulations of the test conditions are performed to validate the inputs.

  14. 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.

  15. 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.

  16. 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....

  17. Microstructure engineering from metallic powder blends for enhanced mechanical properties

    Science.gov (United States)

    Langlois, P.; Fagnon, N.; Dirras, G.

    2010-07-01

    The present work focuses on the transformation of high-purity Ni powder blends of controlled volume fractions (40 and 60 %) of nanometre-sized (100 nm) and micrometre-sized (544 nm) particles into bulk samples as part of a strategy for producing ultrafine-grained materials usefully exhibiting both strength and ductility. The process involved cold isostatic pressing at 1.5 GPa and sintering. The resulting bulk samples had relative densities near 95 %, were texture-free, and exhibited two different grain size distributions with an average value of 600 ± 30 nm. The mechanical properties were investigated by compression and microhardness tests, both at room temperature, and compared to the behaviour of a sample processed from micrometre-sized powder only. Samples prepared from the blends exhibited high yield stresses of 440 and 550 MPa after compression, and they did sustain work hardening. Tests conducted before and after compression up to 50 % deformation showed the same relative amount of hardness increase around 20 %, which was three times lower than that of the monolithic sample for which a decrease of the average grain size close to 26 % was measured.

  18. Computer simulation of the mechanical properties of metamaterials

    Science.gov (United States)

    Gerasimov, R. A.; Eremeyev, V. A.; Petrova, T. O.; Egorov, V. I.; Maksimova, O. G.; Maksimov, A. V.

    2016-08-01

    For a hybrid discrete-continual model describing a system which consists of a substrate and polymer coating, we provide computer simulation of its mechanical properties for various levels of deformations. For the substrate, we apply the elastic model with the Hooke law while for the polymeric coating, we use a discrete model. Here we use the Stockmayer potential which is a Lennard-Jones potential with additional term which describes the dipole interactions between neighbour segments of polymer chains, that is Keesom energy. Using Monte-Carlo method with Metropolis algorithm for a given temperature the equilibrium state is determined. We obtain dependencies of the energy, force, bending moment and Young's modulus for various levels of deformations and for different values of temperature. We show that for the increase of the deformations level the influence of surface coating on the considered material parameters is less pronounced. We provide comparison of obtained results with experimental data on deformations of crystalline polymers (gutta-percha, etc.)

  19. Effect of charge on the mechanical properties of surfactant bilayers.

    Science.gov (United States)

    Bradbury, Robert; Nagao, Michihiro

    2016-11-23

    Charge effects on the mechanical properties of surfactant bilayers have been measured, for a system with a low ionic strength, using small-angle neutron scattering and neutron spin echo spectroscopy. We report that, not only does increasing the surface charge density lead to greater structural ordering and a stiffening of the membrane, which is consistent with classical theory of charge effects on membranes, but also that the relaxation rate of the membrane thickness fluctuations decreases without affecting the fluctuation amplitude. From the relaxation rate we demonstrate, using recent theory, that the viscosity of the surfactant membrane is increased with surface charge density, which suggests that the amount of charge controls the diffusion behavior of inclusions inside the membrane. The present results confirm that the thickness fluctuation relaxation rate and amplitude are tuned independently since the membrane viscosity is only influencing the relaxation rate. This work demonstrates that charge stabilization of lamellar bilayers is not merely affected by intermembrane interactions and structural ordering but that intramembrane dynamics also have a significant contribution.

  20. Mechanical properties of interphase nuclei probed by cellular strain application.

    Science.gov (United States)

    Lammerding, Jan; Lee, Richard T

    2009-01-01

    The mechanical properties of the interphase nucleus have important implications for cellular function and can reflect changes in nuclear envelope structure and/or chromatin organization. Mutations in the nuclear envelope proteins lamin A and C cause several human diseases, such as Emery-Dreifuss muscular dystrophy, and dramatic changes in nuclear stiffness have been reported in cells from lamin A/C-deficient mice. We have developed a cellular strain technique to measure nuclear stiffness in intact, adherent cells and have applied this experimental method to fibroblasts from mouse models of Emery-Dreifuss muscular dystrophy and to skin fibroblasts from laminopathy patients and healthy control subjects. The experimental protocol is based on measuring induced nuclear deformations in cells plated on a flexible silicone substrate; the nuclear stiffness can subsequently be inferred from the ratio of induced nuclear strain to the applied membrane strain. These experiments reveal that lamins A and C are important determinants of nuclear stiffness and that lamin mutations associated with muscular dystrophies and other laminopathies often result in disturbed nuclear stiffness that could contribute to the tissue-specific disease phenotypes.

  1. Effect of substrate mechanical properties on T cell activation

    Science.gov (United States)

    Hui, King; Upadhyaya, Arpita

    2013-03-01

    T cell activation is a key process in cell-mediated immunity, and engagement of T cell receptors by peptides on antigen presenting cells leads to activation of signaling cascades as well as cytoskeletal reorganization and large scale membrane deformations. While significant advances have been made in understanding the biochemical signaling pathways, the effects imposed by the physical environment and the role of mechanical forces on cell activation are not well understood. In this study, we have used anti-CD3 coated elastic polyacrylamide gels as stimulatory substrates to enable the spreading of Jurkat T cells and the measurement of cellular traction forces. We have investigated the effect of substrate stiffness on the dynamics of T cell spreading and cellular force generation. We found that T cells display more active and sustained edge dynamics on softer gels and that they exert increased traction stresses with increasing gel stiffness. A dynamic actin cytoskeleton was required to maintain the forces generated during activation, as inferred from small molecule inhibition experiments. Our results indicate an important role for physical properties of the antigen presenting cell as well as cytoskeleton-driven forces in signaling activation.

  2. Soil mechanical properties at the Apollo 14 site.

    Science.gov (United States)

    Mitchell, J. K.; Bromwell, L. G.; Carrier, W. D., III; Costes, N. C.; Scott, R. F.

    1972-01-01

    The Apollo 14 lunar landing provided a greater amount of information on the mechanical properties of the lunar soil than previous missions. Measurements on core-tube samples and the results of transporter track analyses indicate that the average density of the soil in the Fra Mauro region is in the range from 1.45 to 1.60 g/cu cm. The soil strength appears to be higher in the vicinity of the site of the Apollo 14 lunar surface experiments package, and trench data suggest that strength increases with depth. Lower-bound estimates of soil cohesion give values of 0.03 to 0.10 kN/sq m, which are lower than values of 0.35 to 0.70 kN/sq m estimated for soils encountered in previous missions. The in situ modulus of elasticity, deduced from the measured seismic-wave velocity, is compatible with that to be expected for a terrestrial silty fine sand in the lunar gravitational field.

  3. Microstructure engineering from metallic powder blends for enhanced mechanical properties

    Energy Technology Data Exchange (ETDEWEB)

    Langlois, P; Fagnon, N [LIMHP, Universite Paris 13, CNRS, Institut Galilee, 99 av. J.-B. Clement, 93430 Villetaneuse (France); Dirras, G, E-mail: dirras@univ-paris13.f [LPMTM, Universite Paris 13, CNRS, Institut Galilee, 99 av. J.-B. Clement, 93430 Villetaneuse (France)

    2010-07-01

    The present work focuses on the transformation of high-purity Ni powder blends of controlled volume fractions (40 and 60 %) of nanometre-sized (100 nm) and micrometre-sized (544 nm) particles into bulk samples as part of a strategy for producing ultrafine-grained materials usefully exhibiting both strength and ductility. The process involved cold isostatic pressing at 1.5 GPa and sintering. The resulting bulk samples had relative densities near 95 %, were texture-free, and exhibited two different grain size distributions with an average value of 600 {+-} 30 nm. The mechanical properties were investigated by compression and microhardness tests, both at room temperature, and compared to the behaviour of a sample processed from micrometre-sized powder only. Samples prepared from the blends exhibited high yield stresses of 440 and 550 MPa after compression, and they did sustain work hardening. Tests conducted before and after compression up to 50 % deformation showed the same relative amount of hardness increase around 20 %, which was three times lower than that of the monolithic sample for which a decrease of the average grain size close to 26 % was measured.

  4. COMPARISON OF MECHANICAL PROPERTIES OF DATE PALM FIBER- POLYETHYLENE COMPOSITE

    Directory of Open Access Journals (Sweden)

    Saeed Mahdavi

    2010-09-01

    Full Text Available Date Palm Fiber (DPF is one of the most available natural fibers in the Middle East, especially in Iran and the Persian Gulf region. This research provides a new insight into DPF, with consideration of morphological, chemical characteristics, and bulk density, as well as morphological and mechanical properties of DPF/HDPE wood plastic composite. There are three parts of date palm that are used for producing fiber, the trunk, rachis, and petiole. Results indicated that there is significant difference between trunk and petiole on fiber length but rachis has no significant differences relative to the other parts. The aspect ratios have significant differences among of three parts, with the highest and lowest values measured for the petiole and trunk, respectively. The chemical composition of various parts of the date palm tree differed significantly; with the highest amounts of cellulose and lignin content belong to rachis. Bulk density was measured for three parts of date palm, and the lowest amount was 0.082 g/cm3. The highest strengths were achieved in composites with 30 and 40% fiber content, depended on which original parts of the tree were used.

  5. Microstructure and mechanical properties of lost foam cast 356 alloys

    Directory of Open Access Journals (Sweden)

    Qi-gui Wang

    2015-05-01

    Full Text Available Microstructure and mechanical properties of lost foam cast aluminum alloys have been investigated in both primary A356 (0.13% Fe and secondary 356 (0.47%. As expected, secondary 356 shows much higher content of Fe-rich intermetallic phases, and in particular the porosity in comparison with primary A356. The average area percent and size (length of Fe-rich intermetallics change from about 0.5% and 6 祄 in A356 to 2% and 25 祄 in 356 alloy. The average area percent and maximum size of porosity also increase from about 0.4% and 420 祄 to 1.4% and 600 祄, respectively. As a result, tensile ductility decreases about 60% and ultimate tensile strength declines about 8%. Lower fatigue strength was also experienced in the secondary 356 alloy. Low cycle fatigue (LCF strength decreased from 187 MPa in A356 to 159 MPa in 356 and high cycle fatigue (HCF strength also declined slightly from 68 MPa to 64 MPa.

  6. Numerical modelling of structure and mechanical properties for medical tools

    Directory of Open Access Journals (Sweden)

    L. Jeziorski

    2007-09-01

    Full Text Available Purpose: In order to design forceps and bowl cutter property, it is necessary to optimise many parameters and consider the functions, which these medical tools should fulfil. Of course, some simplifications are necessary in respect of calculation methodology. In the paper a solution procedure concerning this problem has been presented. The presented solution allows for precise determination of the geometrical dimensions according to the functional requirements that forceps should fulfil. The presented numerical analysis describes a small range of the forceps application but the used algorithm can be applied in any other type of forceps. Also in the paper, the numerical simulation results of the bowl cutter being loaded are presented. Residual stress distribution on the tool surface is presented. A position of the cutting edges and holes carrying away the bone chips is shown as a polar diagram. Design/methodology/approach: The numerical analysis was carried out using ADINA software, based on the finite element method (FEM. In the paper some fundamental construction problems occurring during the design process of the forceps and bowl cutter have been discussed.Findings: The iteration procedures in order to optimize the basic construction parameters of the medical tools (forceps and bowl cutter. The calculations allow for determination of the geometrical parameters with reference to the expected spring rate. The charts elaborated on the basis of the calculations are very useful during a design process. The numerical calculations show an essential problem, namely a change in contact surface as a function of load. The observed phenomenon can affect the functioning of the forceps in e negative way.The numerical simulation make it possible to obtain the suitable geometry, better material properties and the instructions heat treatment of these tools. Research limitations/implications: These research was carried out in order to improve ergonomics

  7. Assessment of structural, thermal, and mechanical properties of portlandite through molecular dynamics simulations

    Science.gov (United States)

    Hajilar, Shahin; Shafei, Behrouz

    2016-12-01

    The structural, thermal, and mechanical properties of portlandite, the primary solid phase of ordinary hydrated cement paste, are investigated using the molecular dynamics method. To understand the effects of temperature on the structural properties of portlandite, the coefficients of thermal expansion of portlandite are determined in the current study and validated with what reported from the experimental tests. The atomic structure of portlandite equilibrated at various temperatures is then subjected to uniaxial tensile strains in the three orthogonal directions and the stress-strain curves are developed. Based on the obtained results, the effect of the direction of straining on the mechanical properties of portlandite is investigated in detail. Structural damage analysis is performed to reveal the failure mechanisms in different directions. The energies of the fractured surfaces are calculated in different directions and compared to those of the ideal surfaces available in the literature. The key mechanical properties, including tensile strength, Young's modulus, and fracture strain, are extracted from the stress-strain curves. The sensitivity of the obtained mechanical properties to temperature and strain rate is then explored in a systematic way. This leads to valuable information on how the structural and mechanical properties of portlandite are affected under various exposure conditions and loading rates.

  8. 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.

  9. Mechanical Properties of Plant Cell Walls Probed by Relaxation Spectra

    DEFF Research Database (Denmark)

    Hansen, Steen Laugesen; Ray, Peter Martin; Karlsson, Anders Ola

    2011-01-01

    Transformants and mutants with altered cell wall composition are expected to display a biomechanical phenotype due to the structural role of the cell wall. It is often quite difficult, however, to distinguish the mechanical behavior of a mutant's or transformant's cell walls from that of the wild...... type. This may be due to the plant’s ability to compensate for the wall modification or because the biophysical method that is often employed, determination of simple elastic modulus and breakstrength, lacks the resolving power necessary for detecting subtle mechanical phenotypes. Here, we apply...... a method, determination of relaxation spectra, which probes, and can separate, the viscoelastic properties of different cell wall components (i.e. those properties that depend on the elastic behavior of load-bearing wall polymers combined with viscous interactions between them). A computer program, Bayes...

  10. Short-term Mechanical Properties of Glass Ionomer Cement

    Institute of Scientific and Technical Information of China (English)

    TANG Sanbao; XU Dongxuan

    2009-01-01

    The setting reaction of glass ionomer cement was studied by analyzing and comparing the short-tem mechanical properties of set cement stored in silicone oil,air and distilled water respectively at different temperatures.For the set cement stored at 37℃,the strength of the sample in the air reached the maximum value after 24 h,then decreased to about 210 MPa and kept steady.The strength of the sample in water increased continuously and slowly,however,the increasing rate of sample stored in silicone oil was higher than that in the water.At 20℃,the increasing rate of compressive strength for sample in air was higher than those in silicone oil and water.The diffusion speed and maintenance of water has significant effects on the mechanical properties of glass ionomer cements.

  11. Mechanical Properties of Plant Cell Walls Probed by Relaxation Spectra

    DEFF Research Database (Denmark)

    Hansen, Steen Laugesen; Ray, Peter Martin; Karlsson, Anders Ola

    2011-01-01

    Transformants and mutants with altered cell wall composition are expected to display a biomechanical phenotype due to the structural role of the cell wall. It is often quite difficult, however, to distinguish the mechanical behavior of a mutant's or transformant's cell walls from that of the wild...... type. This may be due to the plant’s ability to compensate for the wall modification or because the biophysical method that is often employed, determination of simple elastic modulus and breakstrength, lacks the resolving power necessary for detecting subtle mechanical phenotypes. Here, we apply...... a method, determination of relaxation spectra, which probes, and can separate, the viscoelastic properties of different cell wall components (i.e. those properties that depend on the elastic behavior of load-bearing wall polymers combined with viscous interactions between them). A computer program, Bayes...

  12. Mechanical properties of homogeneous nanofiber composites fabricated by electrospinning

    Science.gov (United States)

    Watanabe, Kentaro; Hotta, Atsushi

    2013-03-01

    A new composite that possesses uniformly dispersed polymeric nanofibers in different polymeric matrix was introduced by using electrospinning. Recently, nanofibers have been actively investigated for fillers for polymeric nano-composites to enhance the mechanical properties of the composites or to get highly functionalize polymer materials. Polyvinyl alcohol (PVA) nanofibers were selected as polymeric fillers and polydimethylsiloxane (PDMS) was used for polymeric matrix. Internally well-dispersed composites were fabricated by this new method, whereas rather anisotropic composites were also made by the traditional sandwich method. The morphology of the composites was analyzed by field emission scanning electron microscopy (FE-SEM). It was found that, in the new internally well-dispersed composites, PVA nanofibers existed from the both surfaces of the polymer matrix, uniformly dispersed in the composite. Isotropic mechanical properties were observed for internally well-dispersed composites, whereas relatively anisotropic characteristics could be observed for the traditionally-made composites.

  13. Role of sequence and structural polymorphism on the mechanical properties of amyloid fibrils.

    Directory of Open Access Journals (Sweden)

    Gwonchan Yoon

    Full Text Available Amyloid fibrils playing a critical role in disease expression, have recently been found to exhibit the excellent mechanical properties such as elastic modulus in the order of 10 GPa, which is comparable to that of other mechanical proteins such as microtubule, actin filament, and spider silk. These remarkable mechanical properties of amyloid fibrils are correlated with their functional role in disease expression. This suggests the importance in understanding how these excellent mechanical properties are originated through self-assembly process that may depend on the amino acid sequence. However, the sequence-structure-property relationship of amyloid fibrils has not been fully understood yet. In this work, we characterize the mechanical properties of human islet amyloid polypeptide (hIAPP fibrils with respect to their molecular structures as well as their amino acid sequence by using all-atom explicit water molecular dynamics (MD simulation. The simulation result suggests that the remarkable bending rigidity of amyloid fibrils can be achieved through a specific self-aggregation pattern such as antiparallel stacking of β strands (peptide chain. Moreover, we have shown that a single point mutation of hIAPP chain constituting a hIAPP fibril significantly affects the thermodynamic stability of hIAPP fibril formed by parallel stacking of peptide chain, and that a single point mutation results in a significant change in the bending rigidity of hIAPP fibrils formed by antiparallel stacking of β strands. This clearly elucidates the role of amino acid sequence on not only the equilibrium conformations of amyloid fibrils but also their mechanical properties. Our study sheds light on sequence-structure-property relationships of amyloid fibrils, which suggests that the mechanical properties of amyloid fibrils are encoded in their sequence-dependent molecular architecture.

  14. A novel bioreactor to simulate urinary bladder mechanical properties and compliance for bladder functional tissue engineering

    Institute of Scientific and Technical Information of China (English)

    WEI Xin; LI Dao-bing; XU Feng; WANG Yan; ZHU Yu-chun; LI Hong; WANG Kun-jie

    2011-01-01

    Background Bioreactors are pivotal tools for generating mechanical stimulation in functional tissue engineering study.This study aimed to create a bioreactor that can simulate urinary bladder mechanical properties, and to investigate the effects of a mechanically stimulated culture on urothelial cells and bladder smooth muscle cells.Methods We designed a bioreactor to simulate the mechanical properties of bladder. A pressure-record system was used to evaluate the mechanical properties of the bioreactor by measuring the pressure in culture chambers. To test the biocompatibility of the bioreactor, viabilities of urothelial cells and smooth muscle cells cultured in the bioreactor under static and mechanically changed conditions were measured after 7-day culture. To evaluate the effect of mechanical stimulations on the vital cells, urethral cells and smooth muscle cells were cultured in the simulated mechanical conditions. After that, the viability and the distribution pattern of the cells were observed and compared with cells cultured in non-mechanical stimulated condition.Results The bioreactor system successfully generated waveforms similar to the intended programmed model while maintaining a cell-seeded elastic membrane between the chambers. There were no differences between viabilities of urothelial cells ((91.90±1.22)% vs. (93.14±1.78)%, P >0.05) and bladder smooth muscle cells ((93.41±1.49)% vs.(92.61±1.34)%, P >0.05). The viability of cells and tissue structure observation after cultured in simulated condition showed that mechanical stimulation was the only factor affected cells in the bioreactor and improved the arrangement of cells on silastic membrane.Conclusions This bioreactor can effectively simulate the physiological and mechanical properties of the bladder.Mechanical stimulation is the only factor that affected the viability of cells cultured in the bioreactor. The bioreactor can change the growth behavior of urothelial cells and bladder smooth

  15. Study on Mechanical Properties and Components of HRB400 Steel for High-strength Building

    OpenAIRE

    2016-01-01

    The study took five samples of screw-thread steel III, i.e. HRB400 steel bar of different diameters: 10mm, 12mm, 16mm, 20mm and 25mm; and conducted contrast experiments of their mechanical properties and components. The 600 sets of data collected from the experiments were processed by multivariate regression analysis of mechanical properties and components by diameter with MATLAB. The result showed that differentHRB400 screw-thread steel bars have different components with the mechanical prop...

  16. Selective laser melting of titanium alloy: investigation of mechanical properties and microstructure

    Science.gov (United States)

    Agapovichev, A. V.; Kokareva, V. V.; Smelov, V. G.; Sotov, A. V.

    2016-11-01

    This article presents the mechanical properties and microstructure of titanium alloy after selective laser melting (SLM). Titanium alloys are ideal material for selective laser melting (SLM), because they are expensive and difficult to machinery using traditional technologies. The application of SLM in the biomedical area has been slow due to the stringent performance criteria and concerns related to personification and part quality. In this article we focused on the manufacture by SLM and determination of microstructure and mechanical properties of titanium alloy (Ti Grade 2 Powder) using tensile tests and X-ray diffraction. The results reveal that the alloy exhibits a pronounced the homogeneous microstructure and high mechanical strength.

  17. Microstructure and Properties of W-Cu Alloys Prepared with Mechanically Activated Powder

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    W-15% Cu (mass fraction) alloys were sintered with mechanically activated powder in order to develop new preparing processes and improve properties of alloys. The microstructures of the activated powder and the sintered alloy were observed. Properties such as density were measured. The results show that through mechanical activation, the particle size of the powder becomes finer to sub-micron or nanometer level, some copper was soluble in tungsten, and high density W-Cu alloys can be obtained by mechanically activated powder for its action to the activation sintering.

  18. Influence of Hot Deformation and Subsequent Austempering on the Mechanical Properties of Hot Rolled Multiphase Steel

    Institute of Scientific and Technical Information of China (English)

    Zhuang LI; Di WU

    2006-01-01

    Influence of hot deformation and subsequent austempering on the mechanical properties of hot rolled multiphase steel was investigated. Thermo-mechanical control processing (TMCP) was conducted by using a laboratory hot rolling mill, where three different kinds of finishing rolling reduction, and austemperings with various isothermal holding duration were applied. The results have shown that a multiphase microstructure consisting of polygonal ferrite, granular bainite and larger amount of stabilized retained austenite can be obtained by controlled rolling processes. Mechanical properties increase with increasing the amount of deformation because of the stabilization of retained austenite. Ultimate tensile strength (σb), total elongation (δ)36% and 28476 MPa%, respectively) at optimal processes.

  19. Impact and dynamic mechanical thermal properties of textile silk reinforced epoxy resin composites

    Science.gov (United States)

    Yang, K.; Guan, J.

    2016-07-01

    Silk fabric reinforced epoxy resin composites (SFRPs) were prepared using simple techniques of hand lay-up, hot-press and vacuum treatment, and a series of volume fractions of silk reinforcements were achieved. The impact properties and dynamic mechanical properties of SFRPs were investigated using a pendulum impact testing method and dynamic mechanical thermal analysis (DMTA). The results suggest that silk reinforcement could greatly enhance the mechanical performances of SFRPs. The impact strength reached a maximum of 71 kJ/m2 for 60%-silk SFRP, which demonstrated a potential of silk composites for defence and impact- resistant materials.

  20. Microstructures and Mechanical Properties of Fe-Mn-(Al, Si) TRIP/TWIP Steels

    Institute of Scientific and Technical Information of China (English)

    DING Hua; TANG Zheng-You; LI Wei; WANG Mei; SONG Dan

    2006-01-01

    The mechanical properties and microstructure of two low carbon high manganese steels with 23.8% (No.1) and 33% (No.2) (mass percent) of manganese were investigated. The results showed that No.1 steel possesses high strength and high plasticity, and No.2 steel has a relatively high strength and extraordinary plasticity. The No.1 steel exhibits both TRIP (transformation induced plasticity) and TWIP (twin induced plasticity) effects during the deformation; while only TWIP effect appeared under the same deformation condition for No.2 steel. The comparison between the microstructures and mechanical properties of two steels was made, and the strengthening mechanisms were also analyzed.

  1. Mechanical Property Prediction of Commercially Pure Titanium Welds with Artificial Neural Network

    Institute of Scientific and Technical Information of China (English)

    Yanhong WEI; H.K.D.H.Bhadeshia; T. Sourmail

    2005-01-01

    Factors that affect weld mechanical properties of commercially pure titanium have been investigated using artificial neural networks. Input data were obtained from mechanical testing of single-pass, autogenous welds, and neural network models were used to predict the ultimate tensile strength, yield strength, elongation, reduction of area,Vickers hardness and Rockwell B hardness. The results show that both oxygen and nitrogen have the most significant effects on the strength while hydrogen has the least effect over the range investigated. Predictions of the mechanical properties are shown and agree well with those obtained using the 'oxygen equivalent' (OE) equations.

  2. Mechanical properties of polymeric composites with carbon dioxide particles

    Science.gov (United States)

    Moskalyuk, O. A.; Samsonov, A. M.; Semenova, I. V.; Smirnova, V. E.; Yudin, V. E.

    2017-02-01

    Nanocomposites consisting of a polymethylmethacrylate or polystyrene matrix with embedded silicon dioxide nanoparticles surface-modified by silazanes have been prepared by melting technology. The influence of particles on viscoelastic properties of the nanocomposites has been studied using dynamic mechanical analysis. It has been revealed that the addition of 20 wt % of SiO2 raises the flexural modulus of the nanocomposites by 30%.

  3. Microstructure–mechanical property correlation of cryo rolled Zircaloy-4

    Energy Technology Data Exchange (ETDEWEB)

    Sarkar, Apu, E-mail: asarkar5@ncsu.edu; Murty, Korukonda L.

    2015-01-15

    The evolution of microstructure and the mechanical properties of cryo-rolled Zircaloy-4 were both investigated to understand the origin of the alloy’s strength processed at a cryogenic temperature. The correlation of dislocation density, grain size and yield stress of the rolled product indicated that an increase in dislocation density due to the suppression of dynamic recovery is the primary source of strengthening.

  4. Mechanical properties of D0 Run IIB silicon detector staves

    Energy Technology Data Exchange (ETDEWEB)

    Lanfranco, Giobatta; Fast, James; /Fermilab

    2001-06-01

    A proposed stave design for the D0 Run IIb silicon tracker outer layers featuring central cooling channels and a composite shell mechanical structure is evaluated for self-deflection and deflection due to external loads. This paper contains an introduction to the stave structure, a section devoted to composite lamina and laminate properties and finally a section discussing the beam deflections expected for assembled staves using these laminates.

  5. Characterization of Mechanical Properties of Porcelain Tile Using Ultrasonics

    OpenAIRE

    KURAMA, Semra; Eren, Elif

    2012-01-01

    Ultrasound affords a very useful and versatile non-destructive method, using a large application area, for evaluating the microstructure and mechanical properties of materials. In this study, porcelain tiles were sintered at different temperatures to change their porosity. Following this, the time of flight of both longitudinal and shear waves was measured through the tile. The time of flight of ultrasonic waves was measured using a contact ultrasonic transducer operating on a pulse-echo mode...

  6. ORMOSIL thin films: tuning mechanical properties via a nanochemistry approach.

    Science.gov (United States)

    Palmisano, Giovanni; Le Bourhis, Eric; Ciriminna, Rosaria; Tranchida, Davide; Pagliaro, Mario

    2006-12-19

    The mechanical properties (hardness and elastic modulus) of organically modified silicate thin films can be finely tuned by varying the degree of alkylation and thus the fraction of six- and four-membered siloxane rings in the organosilica matrix. This opens the way to large tunability of parameters that are of crucial practical importance for films that are finding increasing application in numerous fields ranging from microelectronics to chemical sensing.

  7. The mechanical properties of density graded hemp/polyethylene composites

    Science.gov (United States)

    Dauvegis, Raphaël; Rodrigue, Denis

    2015-05-01

    In this work, the production and mechanical characterization of density graded biocomposites based on high density polyethylene and hemp fibres was performed. The effect of coupling agent addition (maleated polyethylene) and hemp content (0-30%) was studied to determine the effect of hemp distribution (graded content) inside the composite (uniform, linear, V and Λ). Tensile and flexural properties are reported to compare the structures, especially in terms of their stress-strain behaviors under tensile loading.

  8. In-situ microfibrillar PP–PA6 composites: rheological, morphological and mechanical properties

    Indian Academy of Sciences (India)

    ALI SAFAEI; MAHMOOD MASOOMI; SEYED MOHAMMAD REZA RAZAVI

    2017-09-01

    In this study, the rheology, morphology and mechanical properties of microfibrillar composites based onpolypropylene reinforced with polyamide 6 (PA6) fibres have been investigated. Influence of different factors such as thePA6 composition and drawing ratio on the output of the extruder, and the compatibilizer composition on the properties ofthese composites, were investigated. The results of rheometric mechanical spectrometer rheological measurements and meltflow index (MFI) showed that the storage modulus, loss modulus and complex viscosity of the microfibrillar composites aredirectly related to the composition of PA6. It was also shown that the presence of compatibilizer was the main factor that ledto decrease of some properties including the storage modulus, loss modulus and complex viscosity and increase in the MFI.The results of mechanical tests on samples prepared with different drawing ratios showed that by increasing the drawing ratiofrom 3 to 5, the mechanical properties increase, while increasing draw ratio from 5 to 8 reduces the mechanical properties.With the increase in the composition of the polyamide phase, the tensile strength of microfibrillar composite compatible withpolypropylene-grafted-maleic anhydride initially increased; however, the tensile strength decreased with a high compositionof polyamide phase. Scanning electron microscope images also revealed that the presence of the compatibilizer in themicrofibrillar composites leads to decrease in the number of undeformed drops, while it reduces the micro-fibres diameter,which greatly improved the final properties of the composites.

  9. Effects of Chemotherapy-Induced Alterations in Cell Mechanical Properties on Cancer Metastasis

    Science.gov (United States)

    Prathivadhi, Sruti; Ekpenyong, Andrew; Nichols, Michael; Taylor, Carolyn; Ning, Jianhao

    Biological cells can modulate their mechanical properties to suit their functions and in response to changes in their environment. Thus, mechanical phenotyping of cells has been employed for tracking stem cell differentiation, bacterial infection, cell death, etc. Malignant transformation of cells also involves changes in mechanical properties. However, the extent to which mechanical properties of cancer cells contribute to metastasis is not well understood. Yet, more than 90% of all cancer deaths are directly related to metastasis. Transit of cells through the microcirculation is one of the key features of metastasis. We hypothesize that cancer treatment regimens do inadvertently alter cell mechanical properties in ways that might promote cancer metastasis. We use a microfluidic microcirculation mimetic (MMM) platform which mimics the capillary constrictions of the pulmonary and peripheral microcirculation to determine if in-vivo-like mechanical stimuli can evoke different responses from cells subjected to various cancer drugs. In particular, we show that cancer cells treated with chemotherapeutic drugs such as daunorubicin, become more deformable at short timescales (0.1 s) and transit faster through the device. Our results are first steps in evaluating the pro- or anti-metastatic effects of chemotherapeutic drugs based on their induced alterations in cell mechanical properties.

  10. Structure and mechanical properties of Octopus vulgaris suckers.

    Science.gov (United States)

    Tramacere, Francesca; Kovalev, Alexander; Kleinteich, Thomas; Gorb, Stanislav N; Mazzolai, Barbara

    2014-02-06

    In this study, we investigate the morphology and mechanical features of Octopus vulgaris suckers, which may serve as a model for the creation of a new generation of attachment devices. Octopus suckers attach to a wide range of substrates in wet conditions, including rough surfaces. This amazing feature is made possible by the sucker's tissues, which are pliable to the substrate profile. Previous studies have described a peculiar internal structure that plays a fundamental role in the attachment and detachment processes of the sucker. In this work, we present a mechanical characterization of the tissues involved in the attachment process, which was performed using microindentation tests. We evaluated the elasticity modulus and viscoelastic parameters of the natural tissues (E ∼ 10 kPa) and measured the mechanical properties of some artificial materials that have previously been used in soft robotics. Such a comparison of biological prototypes and artificial material that mimics octopus-sucker tissue is crucial for the design of innovative artificial suction cups for use in wet environments. We conclude that the properties of the common elastomers that are generally used in soft robotics are quite dissimilar to the properties of biological suckers.

  11. [Mechanical properties of wiredrawn Ag-Pd-Cu alloys].

    Science.gov (United States)

    Hasegawa, T; Miyagawa, Y; Nakamura, K

    1989-01-01

    Nine experimental Ag-Pd-Cu ternary alloys, containing 20-30 wt% Pd and 10-20 wt% Cu, were cast into rods 4.5 mm in diameter using an original vacuum/argon-pressure oxide-free casting technique. Test samples 2.0 mm in diameter were made from the rods by wire-drawing. After softening and hardening heat treatments, mechanical properties (modulus of elasticity, elastic limit, proof stress, tensile strength, elongation, and Vickers hardness) of the samples were measured to analyze the effects of composition and fifteen sets of correlations between the mechanical properties on the condition that few internal casting defects existed. After softening heat treatment, values of hardness and strength increased with increasing Cu and Pd contents, while they increased approximately with increasing Pd content after hardening heat treatment. After softening and hardening heat treatments, tensile strength ranged from 44.4 to 60.7 and from 68.1 to 89.1 kgf/mm2, respectively. Values of elongation were more than 10% even after hardening heat treatment. Fourteen out of fifteen correlation coefficients (r) were statistically significant (p less than 0.01). One of the regression lines derived was as follows. Tensile strength (kgf/mm2) = 9.1 +/- 0.305 Hv (r = 0.990) Moreover, the mechanical properties observed in this investigation were compared with those of ordinarily cast samples with the same compositions.

  12. Relationships between supercontraction and mechanical properties of spider silk

    Science.gov (United States)

    Liu, Yi; Shao, Zhengzhong; Vollrath, Fritz

    2005-12-01

    Typical spider dragline silk tends to outperform other natural fibres and most man-made filaments. However, even small changes in spinning conditions can have large effects on the mechanical properties of a silk fibre as well as on its water uptake. Absorbed water leads to significant shrinkage in an unrestrained dragline fibre and reversibly converts the material into a rubber. This process is known as supercontraction and may be a functional adaptation for the silk's role in the spider's web. Supercontraction is thought to be controlled by specific motifs in the silk proteins and to be induced by the entropy-driven recoiling of molecular chains. In analogy, in man-made fibres thermal shrinkage induces changes in mechanical properties attributable to the entropy-driven disorientation of `unfrozen' molecular chains (as in polyethylene terephthalate) or the `broken' intermolecular hydrogen bonds (as in nylons). Here we show for Nephila major-ampullate silk how in a biological fibre the spinning conditions affect the interplay between shrinkage and mechanical characteristics. This interaction reveals design principles linking the exceptional properties of silk to its molecular orientation.

  13. Epoxy Resin Based Composites, Mechanical and Tribological Properties: A Review

    Directory of Open Access Journals (Sweden)

    S.A. Bello

    2015-12-01

    Full Text Available High fuel consumption by automobile and aerospace vehicles built from legacy alloys has been a great challenge to global design and material engineers. This has called for researches into material development for the production of lighter materials of the same or even superior mechanical properties to the existing materials in this area of applications. This forms a part of efforts to achieve the global vision 2025 i.e to reduce the fuel consumption by automobile and aerospace vehicles by at least 75 %. Many researchers have identified advanced composites as suitable materials in this regard. Among the common matrices used for the development of advanced composites, epoxy resin has attained a dominance among its counterparts because of its excellent properties including chemical, thermal and electrical resistance properties, mechanical properties and dimensional stability. This review is a reflection of the extensive study on the currently ongoing research aimed at development of epoxy resin hybrid nanocomposites for engineering applications. In this paper, brief explanation has been given to different terms related to the research work and also, some previous works (in accordance with materials within authors’ reach in the area of the ongoing research have been reported.

  14. Measurement of the Mechanical Properties of Intact Collagen Fibrils

    Science.gov (United States)

    Mercedes, H.; Heim, A.; Matthews, W. G.; Koob, T.

    2006-03-01

    Motivated by the genetic disorder Ehlers-Danlos syndrome (EDS), in which proper collagen synthesis is interrupted, we are investigating the structural and mechanical properties of collagen fibrils. The fibrous glycoprotein collagen is the most abundant protein found in the human body and plays a key role in the extracellular matrix of the connective tissue, the properties of which are altered in EDS. We have selected as our model system the collagen fibrils of the sea cucumber dermis, a naturally mutable tissue. This system allows us to work with native fibrils which have their proteoglycan complement intact, something that is not possible with reconstituted mammalian collagen fibrils. Using atomic force microscopy, we measure, as a function of the concentration of divalent cations, the fibril diameter, its response to force loading, and the changes in its rigidity. Through these experiments, we will shed light on the mechanisms which control the properties of the sea cucumber dermis and hope to help explain the altered connective tissue extracellular matrix properties associated with EDS.

  15. Mechanical Properties and Microstructural Evolution of Welded Eglin Steel

    Science.gov (United States)

    Leister, Brett M.

    Eglin steel is a new ultra-high strength steel that has been developed at Eglin Air Force Base in the early 2000s. This steel could be subjected to a variety of processing steps during fabrication, each with its own thermal history. This article presents a continuous cooling transformation diagram developed for Eglin steel to be used as a guideline during processing. Dilatometry techniques performed on a Gleeble thermo-mechanical simulator were combined with microhardness results and microstructural characterization to develop the diagram. The results show that four distinct microstructures form within Eglin steel depending on the cooling rate. At cooling rates above about 1 °C/s, a predominately martensitic microstructure is formed with hardness of ˜520 HV. Intermediate cooling rates of 1 °C/s to 0.2 °C/s produce a mixed martensitic/bainitic microstructure with a hardness that ranges from 520 - 420 HV. Slower cooling rates of 0.1 °C/s to 0.03 °C/s lead to the formation of a bainitic microstructure with a hardness of ˜420 HV. The slowest cooling rate of 0.01 °C/s formed a bainitic microstructure with pearlite at the prior austenite grain boundaries. A comprehensive study was performed to correlate the mechanical properties and the microstructural evolution in the heat affected zone of thermally simulated Eglin steel. A Gleeble 3500 thermo-mechanical simulator was used to resistively heat samples of wrought Eglin steel according to calculated thermal cycles with different peak temperatures at a heat input of 1500 J/mm. These samples underwent mechanical testing to determine strength and toughness, in both the `as-simulated' condition and also following post-weld heat treatments. Mechanical testing has shown that the inter-critical heat affected zone (HAZ) has the lowest strength following thermal simulation, and the fine-grain and coarse-grain heat affected zone having an increased strength when compared to the inter-critical HAZ. The toughness of the heat

  16. Roles of interfacial reaction on mechanical properties of solder interfaces

    Science.gov (United States)

    Liu, Pilin

    This study investigated roles of interfacial reaction in fracture and fatigue of solder interconnects. The interfacial reaction phases in the as-reflowed and after aging were examined by cross-sectional transmission electron microscopy (TEM) while interfacial mechanical properties were determined from a flexural peel fracture mechanics technique. Because of their widespread uses in microelectronic packaging, SnPb solder interfaces, and Bi-containing Pb-free solder interfaces were chosen as the subjects of this study. In the interfacial reaction study, we observed a complicated micro structural evolution during solid-state aging of electroless-Ni(P)/SnPb solder interconnects. In as-reflowed condition, the interfacial reaction produced Ni3Sn 4 and P-rich layers. Following overaging, the interfacial microstructure degenerated into a complex multilayer structure consisting of multiple layers of Ni-Sn compounds and transformed Ni-P phases. In SnPb solder interfacial system, fatigue study showed that the overaging of the high P electroless Ni-P/SnPb interconnects resulted in a sharp reduction in the fatigue resistance of the interface in the high crack growth rate regime. Fracture mechanism analysis indicated that the sharp drop in fatigue resistance was triggered by the brittle fracture of the Ni3Sn2 intermetallic phase developed at the overaged interface. The fatigue behavior was strongly dependent on P concentration in electroless Ni. Kirkendall voids were found in the interfacial region after aging, but they did not cause premature fracture of the solder interfaces. In Bi-containing solder interfacial system, we found that Bi segregated to the Cu-intermetallic interface during aging in SnBi/Cu interconnect. This caused serious embrittlement of Sn-Bi/Cu interface. Further aging induced numerous voids along the Cu3Sn/Cu interface. These interfacial voids were different from Kirkendall voids. Their formation was explained on basis of vacancy condensation at the

  17. DTA and DSC study on the effect of mechanical dispersion on poly(tetrafluorethylene properties

    Directory of Open Access Journals (Sweden)

    Dumitraşa Mihai

    2014-12-01

    Full Text Available Poly(tetrafluorethylene particles were obtained by mechanical processing of the formed polymer (Teflon bar. In order to assess the effect of mechanical wear on polymer properties, their melting and crystallization behaviour was investigated by DSC and DTA, and the results were compared to the ones obtained for the native polymer. An increase of the crystallinity degree and an accentuated decrease of the average molecular weight were found for the samples submitted to mechanical wear, as a result of mechanical degradation of the polymer

  18. Morphology, Mechanical and Thermal Properties of PBT-TiO2 Polymer Nanocomposite

    OpenAIRE

    Metanawin Tanapak; Jamjumrus Anusorn; Metanawin Siripan

    2015-01-01

    This research aims to study the effects of the TiO2 in PBT composite fibers on the thermal properties, mechanical properties and photocatalytic properties of the polymer composite. The results showed that the tensile strength of the TiO2/PBT fibers decreased with increasing in the content of TiO2 in polymer matrix. The content of TiO2 in composite fibers did not affect the thermal properties of the fibers but the %crystalline of the composite fibers were increased with content of TiO2 in the ...

  19. Mechanical and thermal properties of irradiated films based on Tilapia (Oreochromis niloticus) proteins

    Energy Technology Data Exchange (ETDEWEB)

    Sabato, S.F. [Radiation Technology Center, IPEN-CNEN/SP, Av. Lineu Prestes 2242, 05508 900 Sao Paulo, SP (Brazil)], E-mail: sfsabato@ipen.br; Nakamurakare, N.; Sobral, P.J.A. [Food Engineering Department, ZEA/FZEA/USP, Av. Duque de Caxias Norte 225, 13635 900 Pirassununga, SP (Brazil)

    2007-11-15

    Proteins are considered potential material in natural films as alternative to traditional packaging. When gamma radiation is applied to protein film forming solution it resulted in an improvement in mechanical properties of whey protein films. The objective of this work was the characterization of mechanical and thermal properties of irradiated films based on muscle proteins from Nile Tilapia (Oreochromis niloticus). The films were prepared according to a casting technique with two levels of plasticizer: 25% and 45% glycerol and irradiated in electron accelerator type Radiation Dynamics, 0.550 MeV at dose range from 0 to 200 kGy. Thermal properties and mechanical properties were determined using a differential scanning calorimeter and a texture analyzer, respectively. Radiation from electron beam caused a slightly increase on its tensile strength characteristic at 100 kGy, while elongation value at this dose had no reduction.

  20. Experimental study of mechanical properties of friction welded AISI 1021 steels

    Indian Academy of Sciences (India)

    Amit Handa; Vikas Chawla

    2013-12-01

    Friction welding is widely used as a mass production method in various industries. In the present study, an experimental set-up was designed in order to achieve friction welding of plastically deformed AISI 1021 steels. In this study, low alloy steel (AISI 1021) was welded under different welding parameters and afterwards the mechanical properties such as tensile strength, impact strength and hardness were experimentally determined. On the basis of the results obtained from the experimentation, the graphs were plotted. It is the strength of welded joints, which is fundamental property to the service reliability of the weldments and hence present work was undertaken to study the influence of axial pressure and rotational speed in friction welded joints. Axial pressure and rotational speed are the two major parameters which can influence the strength and hence the mechanical properties of the friction welded joints. Thus the axial pressure and rotational speed were taken as welding parameters, which reflect the mechanical properties.

  1. Mechanical and thermal properties of irradiated films based on Tilapia ( Oreochromis niloticus) proteins

    Science.gov (United States)

    Sabato, S. F.; Nakamurakare, N.; Sobral, P. J. A.

    2007-11-01

    Proteins are considered potential material in natural films as alternative to traditional packaging. When gamma radiation is applied to protein film forming solution it resulted in an improvement in mechanical properties of whey protein films. The objective of this work was the characterization of mechanical and thermal properties of irradiated films based on muscle proteins from Nile Tilapia ( Oreochromis niloticus). The films were prepared according to a casting technique with two levels of plasticizer: 25% and 45% glycerol and irradiated in electron accelerator type Radiation Dynamics, 0.550 MeV at dose range from 0 to 200 kGy. Thermal properties and mechanical properties were determined using a differential scanning calorimeter and a texture analyzer, respectively. Radiation from electron beam caused a slightly increase on its tensile strength characteristic at 100 kGy, while elongation value at this dose had no reduction.

  2. Mechanical properties of DNA origami nanoassemblies are determined by Holliday junction mechanophores.

    Science.gov (United States)

    Shrestha, Prakash; Emura, Tomoko; Koirala, Deepak; Cui, Yunxi; Hidaka, Kumi; Maximuck, William J; Endo, Masayuki; Sugiyama, Hiroshi; Mao, Hanbin

    2016-08-19

    DNA nanoassemblies have demonstrated wide applications in various fields including nanomaterials, drug delivery and biosensing. In DNA origami, single-stranded DNA template is shaped into desired nanostructure by DNA staples that form Holliday junctions with the template. Limited by current methodologies, however, mechanical properties of DNA origami structures have not been adequately characterized, which hinders further applications of these materials. Using laser tweezers, here, we have described two mechanical properties of DNA nanoassemblies represented by DNA nanotubes, DNA nanopyramids and DNA nanotiles. First, mechanical stability of DNA origami structures is determined by the effective density of Holliday junctions along a particular stress direction. Second, mechanical isomerization observed between two conformations of DNA nanotubes at 10-35 pN has been ascribed to the collective actions of individual Holliday junctions, which are only possible in DNA origami with rotational symmetric arrangements of Holliday junctions, such as those in DNA nanotubes. Our results indicate that Holliday junctions control mechanical behaviors of DNA nanoassemblies. Therefore, they can be considered as 'mechanophores' that sustain mechanical properties of origami nanoassemblies. The mechanical properties observed here provide insights for designing better DNA nanostructures. In addition, the unprecedented mechanical isomerization process brings new strategies for the development of nano-sensors and actuators.

  3. Optical measurement of arterial mechanical properties: from atherosclerotic plaque initiation to rupture

    Science.gov (United States)

    Nadkarni, Seemantini K.

    2013-12-01

    During the pathogenesis of coronary atherosclerosis, from lesion initiation to rupture, arterial mechanical properties are altered by a number of cellular, molecular, and hemodynamic processes. There is growing recognition that mechanical factors may actively drive vascular cell signaling and regulate atherosclerosis disease progression. In advanced plaques, the mechanical properties of the atheroma influence stress distributions in the fibrous cap and mediate plaque rupture resulting in acute coronary events. This review paper explores current optical technologies that provide information on the mechanical properties of arterial tissue to advance our understanding of the mechanical factors involved in atherosclerosis development leading to plaque rupture. The optical approaches discussed include optical microrheology and traction force microscopy that probe the mechanical behavior of single cell and extracellular matrix components, and intravascular imaging modalities including laser speckle rheology, optical coherence elastography, and polarization-sensitive optical coherence tomography to measure the mechanical properties of advanced coronary lesions. Given the wealth of information that these techniques can provide, optical imaging modalities are poised to play an increasingly significant role in elucidating the mechanical aspects of coronary atherosclerosis in the future.

  4. Mechanical properties and formation mechanisms of a wire of single gold atoms

    DEFF Research Database (Denmark)

    Rubio-Bollinger, G.; Bahn, Sune Rastad; Agrait, N.

    2001-01-01

    A scanning tunneling microscope supplemented with a force sensor is used to study the mechanical properties of a novel metallic nanostructure: a freely suspended chain of single gold atoms. We find that the bond strength of the nanowire is about twice that of a bulk metallic bond. We perform ab i...

  5. Characterisation of Dynamic Mechanical Properties of Resistance Welding Machines

    DEFF Research Database (Denmark)

    Wu, Pei; Zhang, Wenqi; Bay, Niels

    2005-01-01

    The dynamic mechanical properties of a resistance welding machine have significant influence on weld quality, which must be considered when simulating the welding process numerically. However, due to the complexity of the machine structure and the mutual coupling of components of the machine system...... characterizing the dynamic mechanical characteristics of resistance welding machines is suggested, and a test set-up is designed determining the basic, independent machine parameters required in the model. The model is verified by performing a series of mechanical tests as well as real projection welds......., it is very difficult to measure or calculate the basic, independent machine parameters required in a mathematical model of the machine dynamics, and no test method has so far been presented in literature, which can be applied directly in an industrial environment. In this paper, a mathematical model...

  6. Characterisation of Dynamic Mechanical Properties of Resistance Welding Machines

    DEFF Research Database (Denmark)

    Wu, Pei; Zhang, Wenqi; Bay, Niels

    2005-01-01

    The dynamic mechanical properties of a resistance welding machine have significant influence on weld quality, which must be considered when simulating the welding process numerically. However, due to the complexity of the machine structure and the mutual coupling of components of the machine system......, it is very difficult to measure or calculate the basic, independent machine parameters required in a mathematical model of the machine dynamics, and no test method has so far been presented in literature, which can be applied directly in an industrial environment. In this paper, a mathematical model...... characterizing the dynamic mechanical characteristics of resistance welding machines is suggested, and a test set-up is designed determining the basic, independent machine parameters required in the model. The model is verified by performing a series of mechanical tests as well as real projection welds....

  7. A novel bioreactor to simulate urinary bladder mechanical properties and compliance for bladder functional tissue engineering.

    Science.gov (United States)

    Wei, Xin; Li, Dao-bing; Xu, Feng; Wang, Yan; Zhu, Yu-chun; Li, Hong; Wang, Kun-jie

    2011-02-01

    Bioreactors are pivotal tools for generating mechanical stimulation in functional tissue engineering study. This study aimed to create a bioreactor that can simulate urinary bladder mechanical properties, and to investigate the effects of a mechanically stimulated culture on urothelial cells and bladder smooth muscle cells. We designed a bioreactor to simulate the mechanical properties of bladder. A pressure-record system was used to evaluate the mechanical properties of the bioreactor by measuring the pressure in culture chambers. To test the biocompatibility of the bioreactor, viabilities of urothelial cells and smooth muscle cells cultured in the bioreactor under static and mechanically changed conditions were measured after 7-day culture. To evaluate the effect of mechanical stimulations on the vital cells, urethral cells and smooth muscle cells were cultured in the simulated mechanical conditions. After that, the viability and the distribution pattern of the cells were observed and compared with cells cultured in non-mechanical stimulated condition. The bioreactor system successfully generated waveforms similar to the intended programmed model while maintaining a cell-seeded elastic membrane between the chambers. There were no differences between viabilities of urothelial cells ((91.90 ± 1.22)% vs. (93.14 ± 1.78)%, P > 0.05) and bladder smooth muscle cells ((93.41 ± 1.49)% vs. (92.61 ± 1.34)%, P > 0.05). The viability of cells and tissue structure observation after cultured in simulated condition showed that mechanical stimulation was the only factor affected cells in the bioreactor and improved the arrangement of cells on silastic membrane. This bioreactor can effectively simulate the physiological and mechanical properties of the bladder. Mechanical stimulation is the only factor that affected the viability of cells cultured in the bioreactor. The bioreactor can change the growth behavior of urothelial cells and bladder smooth muscle cells, resulting in

  8. Spherical agglomerates of lactose with enhanced mechanical properties.

    Science.gov (United States)

    Lamešić, Dejan; Planinšek, Odon; Lavrič, Zoran; Ilić, Ilija

    2017-01-10

    The aim of this study was to prepare spherical agglomerates of lactose and to evaluate their physicochemical properties, flow properties, particle friability and compaction properties, and to compare them to commercially available types of lactose for direct compression (spray-dried, granulated and anhydrous β-lactose). Porous spherical agglomerates of α-lactose monohydrate with radially arranged prism-like primary particles were prepared exhibiting a high specific surface area. All types of lactose analysed had passable or better flow properties, except for anhydrous β-lactose, which had poor flowability. Particle friability was more pronounced in larger granulated lactose particles; however, particle structure was retained in all samples analysed. The mechanical properties of spherical agglomerates of lactose, in terms of compressibility, established with Walker analysis, and compactibility, established with a compactibility profile, were found to be superior to any commercially available types of lactose. Higher compactibility of spherical agglomerates of lactose is ascribed to significantly higher particle surface area due to a unique internal structure with higher susceptibility to fragmentation. Copyright © 2016 Elsevier B.V. All rights reserved.

  9. Mechanical and hydraulic properties of rocks related to induced seismicity

    Science.gov (United States)

    Witherspoon, P.A.; Gale, J.E.

    1977-01-01

    Witherspoon, P.A. and Gale, J.E., 1977. Mechanical and hydraulic properties of rocks related to induced seismicity. Eng. Geol., 11(1): 23-55. The mechanical and hydraulic properties of fractured rocks are considered with regard to the role they play in induced seismicity. In many cases, the mechanical properties of fractures determine the stability of a rock mass. The problems of sampling and testing these rock discontinuities and interpreting their non-linear behavior are reviewed. Stick slip has been proposed as the failure mechanism in earthquake events. Because of the complex interactions that are inherent in the mechanical behavior of fractured rocks, there seems to be no simple way to combine the deformation characteristics of several sets of fractures when there are significant perturbations of existing conditions. Thus, the more important fractures must be treated as individual components in the rock mass. In considering the hydraulic properties, it has been customary to treat a fracture as a parallel-plate conduit and a number of mathematical models of fracture systems have adopted this approach. Non-steady flow in fractured systems has usually been based on a two-porosity model, which assumes the primary (intergranular) porosity contributes only to storage and the secondary (fracture) porosity contributes only to the overall conductivity. Using such a model, it has been found that the time required to achieve quasi-steady state flow in a fractured reservoir is one or two orders of magnitude greater than it is in a homogeneous system. In essentially all of this work, the assumption has generally been made that the fractures are rigid. However, it is clear from a review of the mechanical and hydraulic properties that not only are fractures easily deformed but they constitute the main flow paths in many rock masses. This means that one must consider the interaction of mechanical and hydraulic effects. A considerable amount of laboratory and field data is now

  10. Thermal and mechanical interfacial properties of the DGEBA/PMR-15 blend system.

    Science.gov (United States)

    Park, Soo-Jin; Lee, Hwa-Young; Han, Mijeong; Hong, Sung-Kwon

    2004-02-15

    In this work, the blend system of diglycidyl ether of bisphenol A and PMR-15 polyimide is investigated in terms of thermal and dynamic mechanical interfacial properties of the casting specimens. The thermal stabilities are studied by thermogravimetric and thermomechanical analyses, and the dynamic mechanical properties are carried out by dynamic mechanical analysis. The results show that the thermal stabilities based on the initial decomposition temperature, the integral procedural decomposition temperature, and the glass transition temperature are increased with increasing PMR-15 content. The crosslinking density (rho) of the blend system is increased at 10 phr of PMR-15, compared with that of neat epoxy. Mechanical interfacial properties measured in the context of critical stress intensity factor and critical strain energy release rate show similar behaviors with E(a) and rho, probably due to the increase in intermolecular interactions or hydrogen bondings in polymer chains.

  11. Effect of equilibrium moisture content on barrier, mechanical and thermal properties of chitosan films.

    Science.gov (United States)

    Aguirre-Loredo, Rocío Yaneli; Rodríguez-Hernández, Adriana Inés; Morales-Sánchez, Eduardo; Gómez-Aldapa, Carlos Alberto; Velazquez, Gonzalo

    2016-04-01

    Water molecules modify the properties of biodegradable films obtained from hydrophilic materials. Most studies dealing with thermal, mechanical and barrier properties of hydrophilic films are carried out under one relative humidity (RH) condition. The objective of this work was to evaluate the effect of the moisture content on the thermal, mechanical and barrier properties of chitosan films under several RH conditions. Microclimates, obtained with saturated salt solutions were used for conditioning samples and the properties of the films were evaluated under each RH condition. Chitosan films absorbed up to 40% of moisture at the higher RH studied. The percentage of elongation and the water vapour permeability increased while tensile strength, Young's modulus and glass transition temperature decreased, when the moisture content increased. The results suggest that the water molecules plasticized the polymer matrix, changing the properties when the films were in contact with high RH environments.

  12. Mechanical Properties of a Single Cancellous Bone Trabeculae Taken from Bovine Femur

    Science.gov (United States)

    Enoki, Shinichi; Sato, Mitsuhiro; Tanaka, Kazuto; Katayama, Tsutao

    The increase of patients with osteoporosis is becoming a social problem, thus it is an urgent issue to find its prevention and treatment methods. Since cancellous bone is metabolically more active than cortical bone, cancellous bone is often used for diagnosis of osteoporosis and has received much attention within the study of bone. Bone is a hierarchically structured material and its mechanical properties vary at different structural levels, therefore it is important to break down the mechanical testing of bone according to the various levels within bone material. Mechanical properties of cancellous bone is said to be depended on quantities and orientation of trabecular bone. It is supposed that mechanical properties of trabecular bone are constant without depending on any structural arrangement and parts. However, such assumption has not been established in studies of trabecular bone. Furthermore test results have a large margin of error caused by insufficient shape assessment. In this study, three point bending tests of single cancellous bone trabeculae extracted from bovine femur were conducted to evaluate the effects of directions to the femur major axis direction on the mechanical properties. X-ray μCT was used to obtain shape of trabecular bone specimens. Furthermore compression tests of cancellous bone specimens, which were extracted in 10mm cubic geometry, were conducted for evaluation of directional properties.There were small difference in the elastic modulus of the trabecular bones which were extracted in parallel and in perpendicular to the major axis of femur. Considering from the results that the cancellous bone specimens, which were extracted in 10mm cubic geometry, have different elastic properties depending on the tested directions; the bone structure has larger influence than bone material property on the mechanical properties of cancellous bone.

  13. Mechanical properties of femoral trabecular bone in dogs

    Directory of Open Access Journals (Sweden)

    Nolte Ingo

    2005-03-01

    Full Text Available Abstract Background Studying mechanical properties of canine trabecular bone is important for a better understanding of fracture mechanics or bone disorders and is also needed for numerical simulation of canine femora. No detailed data about elastic moduli and degrees of anisotropy of canine femoral trabecular bone has been published so far, hence the purpose of this study was to measure the elastic modulus of trabecular bone in canine femoral heads by ultrasound testing and to assess whether assuming isotropy of the cancellous bone in femoral heads in dogs is a valid simplification. Methods From 8 euthanized dogs, both femora were obtained and cubic specimens were cut from the centre of the femoral head which were oriented along the main pressure and tension trajectories. The specimens were tested using a 100 MHz ultrasound transducer in all three orthogonal directions. The directional elastic moduli of trabecular bone tissue and degrees of anisotropy were calculated. Results The elastic modulus along principal bone trajectories was found to be 11.2 GPa ± 0.4, 10.5 ± 2.1 GPa and 10.5 ± 1.8 GPa, respectively. The mean density of the specimens was 1.40 ± 0.09 g/cm3. The degrees of anisotropy revealed a significant inverse relationship with specimen densities. No significant differences were found between the elastic moduli in x, y and z directions, suggesting an effective isotropy of trabecular bone tissue in canine femoral heads. Discussion This study presents detailed data about elastic moduli of trabecular bone tissue obtained from canine femoral heads. Limitations of the study are the relatively small number of animals investigated and the measurement of whole specimen densities instead of trabecular bone densities which might lead to an underestimation of Young's moduli. Publications on elastic moduli of trabecular bone tissue present results that are similar to our data. Conclusion This study provides data about directional elastic

  14. Estimation of mechanical properties of single wall carbon nanotubes using molecular mechanics approach

    Indian Academy of Sciences (India)

    P Subba Rao; Sunil Anandatheertha; G Narayana Naik; G Gopalakrishnan

    2015-06-01

    Molecular mechanics based finite element analysis is adopted in the current work to evaluate the mechanical properties of Zigzag, Armchair and Chiral Single wall Carbon Nanotubes (SWCNT) of different diameters and chiralities. Three different types of atomic bonds, that is Carbon–Carbon covalent bond and two types of Carbon–Carbon van der Waals bonds are considered in the carbon nanotube system. The stiffness values of these bonds are calculated using the molecular potentials, namely Morse potential function and Lennard-Jones interaction potential function respectively and these stiffness’s are assigned to spring elements in the finite element model of the CNT. The geometry of CNT is built using a macro that is developed for the finite element analysis software. The finite element model of the CNT is constructed, appropriate boundary conditions are applied and the behavior of mechanical properties of CNT is studied.

  15. Effects of fibre orientation on mechanical properties of hybrid bamboo/glass fibre polymer composites

    Indian Academy of Sciences (India)

    B Stanly Jones Retnam; M Sivapragash; P Pradeep

    2014-08-01

    The usage of natural fibre as reinforcement in polymer composites have widely increased because of its enhanced properties. The usage of plant fibre cannot alone satisfy all the needs of the composites. Hence, introduction of hybrid plays a vital role in enhancing the mechanical properties of the FRP composites. Fibre orientation contributes significant role in improving the mechanical properties of the FRP composites. In this proposal, hybrid bamboo/glass fibre woven in different orientations such as 0°/90° and ± 45° was used and its effect on mechanical properties were studied. Composites containing hybrid fibres found to possess better mechanical properties, when compared to pure bamboo. In order to justify this, the following mechanical properties such as tensile, flexural, impact and hardness were investigated. SEM analysis shows the bonding between the matrix and reinforcement. All the above test results indicate that the introduction of natural bamboo fibre in glass reduces the overall cost of the composites with no compromise in strength and also attracted several studies covering green technologies.

  16. Mechanical properties of sintered meso-porous silicon: a numerical model.

    Science.gov (United States)

    Martini, Roberto; Depauw, Valerie; Gonzalez, Mario; Vanstreels, Kris; Nieuwenhuysen, Kris Van; Gordon, Ivan; Poortmans, Jef

    2012-10-29

    : Because of its optical and electrical properties, large surfaces, and compatibility with standard silicon processes, porous silicon is a very interesting material in photovoltaic and microelectromechanical systems technology. In some applications, porous silicon is annealed at high temperature and, consequently, the cylindrical pores that are generated by anodization or stain etching reorganize into randomly distributed closed sphere-like pores. Although the design of devices which involve this material needs an accurate evaluation of its mechanical properties, only few researchers have studied the mechanical properties of porous silicon, and no data are nowadays available on the mechanical properties of sintered porous silicon. In this work we propose a finite element model to estimate the mechanical properties of sintered meso-porous silicon. The model has been employed to study the dependence of the Young's modulus and the shear modulus (upper and lower bounds) on the porosity for porosities between 0% to 40%. Interpolation functions for the Young's modulus and shear modulus have been obtained, and the results show good agreement with the data reported for other porous media. A Monte Carlo simulation has also been employed to study the effect of the actual microstructure on the mechanical properties.

  17. Mechanical properties of lunar regolith and lunar soil simulant

    Science.gov (United States)

    Perkins, Steven W.

    1989-01-01

    Through the Surveyor 3 and 7, and Apollo 11-17 missions a knowledge of the mechanical properties of Lunar regolith were gained. These properties, including material cohesion, friction, in-situ density, grain-size distribution and shape, and porosity, were determined by indirect means of trenching, penetration, and vane shear testing. Several of these properties were shown to be significantly different from those of terrestrial soils, such as an interlocking cohesion and tensile strength formed in the absence of moisture and particle cementation. To characterize the strength and deformation properties of Lunar regolith experiments have been conducted on a lunar soil simulant at various initial densities, fabric arrangements, and composition. These experiments included conventional triaxial compression and extension, direct tension, and combined tension-shear. Experiments have been conducted at low levels of effective confining stress. External conditions such as membrane induced confining stresses, end platten friction and material self weight have been shown to have a dramatic effect on the strength properties at low levels of confining stress. The solution has been to treat these external conditions and the specimen as a full-fledged boundary value problem rather than the idealized elemental cube of mechanics. Centrifuge modeling allows for the study of Lunar soil-structure interaction problems. In recent years centrifuge modeling has become an important tool for modeling processes that are dominated by gravity and for verifying analysis procedures and studying deformation and failure modes. Centrifuge modeling is well established for terrestrial enginering and applies equally as well to Lunar engineering. A brief review of the experiments is presented in graphic and outline form.

  18. Longitudinal Mechanical Properties of Small-Diameter Polyurethane Vascular Graft Reinforced by Tubular Knitted Fabric

    Institute of Scientific and Technical Information of China (English)

    ZHOU Fei; XU Wei-lin; OUYANG Chen-xi; LIU Xiu-ying; XU Hai-ye; YAO Mu

    2008-01-01

    The vascular graft with 4 nun diameter was prepared by casting one layer of polyurethane (PU) film onto the knitting tubular fabric as the reinforced support. The effects of different PU content and wall thickness on the longitudinal mechanical properties of vascular graft were investigated. The breaking elongation, breaking force, initial modulus and breaking work were studied. The results showed that the longitudinal mechanical properties of vascular graft were enhanced as the content of polyurethane increased, which resulted from the combination of PU excellent elasticity and fabric preferable strength.

  19. Development of data base with mechanical properties of un- and pre-irradiated VVER cladding

    Energy Technology Data Exchange (ETDEWEB)

    Asmolov, V.; Yegorova, L.; Kaplar, E.; Lioutov, K. [Nuclear Safety Inst. of Russian Research Centre, Moscow (Russian Federation). Kurchatov Inst.; Smirnov, V.; Prokhorov, V.; Goryachev, A. [State Research Centre, Dimitrovgrad (Russian Federation). Research Inst. of Atomic Reactors

    1998-03-01

    Analysis of recent RIA test with PWR and VVER high burnup fuel, performed at CABRI, NSRR, IGR reactors has shown that the data base with mechanical properties of the preirradiated cladding is necessary to interpret the obtained results. During 1997 the corresponding cycle of investigations for VVER clad material was performed by specialists of NSI RRC KI and RIAR in cooperation with NRC (USA), IPSN (France) in two directions: measurements of mechanical properties of Zr-1%Nb preirradiated cladding versus temperature and strain rate; measurements of failure parameters for gas pressurized cladding tubes. Preliminary results of these investigations are presented in this paper.

  20. Effect of Graphite Content and Granularity on Mechanical and Tribological Properties of Bronze Alloyed Powder Composite

    Institute of Scientific and Technical Information of China (English)

    DENG Chen-hong; CHEN Guang-zhi; GE Qi-lu

    2005-01-01

    The bronze alloyed powder composite containing nanoparticles was developed by hot pressing. The effects of the content and granularity of graphite on hardness, machinability, bending strength, compression strength, and friction and wear behavior of the composites were studied. The microstructures of the specimens were analyzed by SEM. The results showed that the graphites are distributed in net when nanographites are added, resulting in the decrease of mechanical properties and abrasive resistance. When the content of nanographite is 10%, the composite is brittle. The graphite is distributed in the form of block when micrographite is added, improving the mechanical properties and abrasive resistance. Wear track was studied by SEM.