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Marc A. Meyers

Bio: Marc A. Meyers is an academic researcher from University of California, San Diego. The author has contributed to research in topics: Deformation (engineering) & Dislocation. The author has an hindex of 85, co-authored 487 publications receiving 36646 citations. Previous affiliations of Marc A. Meyers include University of California & Instituto Militar de Engenharia.


Papers
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Journal ArticleDOI
01 Jul 2006-JOM
TL;DR: In this article, the overall design principles in biological structural composites and illustrates them for five examples; sea spicules, the abalone shell, conch shell, the toucan and hornbill beaks, and the sheep crab exoskeleton.
Abstract: Biological materials are complex composites that are hierarchically structured and multifunctional. Their mechanical properties are often outstanding, considering the weak constituents from which they are assembled. They are for the most part composed of brittle (often, mineral) and ductile (organic) components. These complex structures, which have risen from millions of years of evolution, are inspiring materials scientists in the design of novel materials. This paper discusses the overall design principles in biological structural composites and illustrates them for five examples; sea spicules, the abalone shell, the conch shell, the toucan and hornbill beaks, and the sheep crab exoskeleton.

131 citations

Journal ArticleDOI
TL;DR: In this paper, the mechanisms of deformation under a nanoindentation in tantalum, chosen as a model body-centered cubic (bcc) metal, are identified and quantified.

129 citations

Journal ArticleDOI
TL;DR: In this paper, the adiabatic shear bands formed in a hollow AISI 4340 steel cylinder subjected to dynamic expansion by means of an explosive charge placed in its longitudinal axis, were characterized.
Abstract: Adiabatic shear bands, formed in a hollow AISI 4340 steel cylinder subjected to dynamic expansion by means of an explosive charge placed in its longitudinal axis, were characterized. The adiabatic shear bands formed in this quenched and tempered steel were of the classical “transformed” type. Scanning electron microscopy (SEM) of etched surfaces revealed that alignment of the lamellae along the direction of shear seems to be the event that precedes shear localization. The transmission electron microscopy of a “white”-etching shear band having undergone a shear strain of approximately 4 revealed that it containedX (Fe5C2) carbides in a martensitic structure. These carbides were observed to form on (112) internal microtwins. Grains could not be resolved inside of the shear band, but they could be observed in the surrounding matrix material. A traverse of the shear band was made, and there existed no definite boundary between the matrix and the shear band. No evidence of a transformation to austenite was observed. Heat transfer calculations were conducted to help explain the features observed inside of the shear band. It is concluded that the “white”-etching bands, commonly referred to in the literature as “transformed” bands, do not exhibit a transformation at values of shear strain of up to 4. The enhanced reflectivity is an etching artifact and is possibly due to microstructural changes, a very small grain size, and carbide redissolution in the bands.

123 citations

Journal ArticleDOI
TL;DR: In this article, the authors investigated the damage evolution in silicon carbide by subjecting it to dynamic deformation in a compression Hopkinson-Kolsky bar (compressive stresses of 5 GPa), and a high-velocity impact under confinement (compressed stresses of 19-32 GPa) by a cylindrical tungsten alloy projectile.

122 citations

Journal ArticleDOI
TL;DR: In this paper, the structural and mechanical properties of TiO2 freeze cast with different soluble additives, including polyethylene glycol, NaOH or HCl, and isopropanol alcohol, are characterized to determine the effects of slurry viscosity, pH, and alcohol concentration on the freezing process.
Abstract: Scaffolds with potential biological applications having a variety of microstructural and mechanical properties can be fabricated by freezing colloidal solutions into porous solids. In this work, the structural and mechanical properties of TiO2 freeze cast with different soluble additives, including polyethylene glycol, NaOH or HCl, and isopropanol alcohol, are characterized to determine the effects of slurry viscosity, pH, and alcohol concentration on the freezing process. TiO2 powders mixed with water and these different additives are directionally frozen in a mold, then sublimated and sintered to create the porous scaffolds. The different scaffolds are characterized to compare the compressive strength, modulus, porosity, and pore morphology. For all scaffolds, the overall porosity remains constant (80–85%). By changing the concentration of each additive, the lamellar thickness, pore area, and aspect ratio vary significantly, showing inverse relationships to both the compressive strength and modulus. The strength is predicted from the pore aspect ratio of the scaffolds when subjected to compressive loading with the primary failure mode identified as Euler buckling. TiO2 scaffolds freeze cast with different soluble additives are suitable for biomedical applications, such as bone replacements, requiring high porosity and specific pore morphologies.

122 citations


Cited by
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01 May 1993
TL;DR: Comparing the results to the fastest reported vectorized Cray Y-MP and C90 algorithm shows that the current generation of parallel machines is competitive with conventional vector supercomputers even for small problems.
Abstract: Three parallel algorithms for classical molecular dynamics are presented. The first assigns each processor a fixed subset of atoms; the second assigns each a fixed subset of inter-atomic forces to compute; the third assigns each a fixed spatial region. The algorithms are suitable for molecular dynamics models which can be difficult to parallelize efficiently—those with short-range forces where the neighbors of each atom change rapidly. They can be implemented on any distributed-memory parallel machine which allows for message-passing of data between independently executing processors. The algorithms are tested on a standard Lennard-Jones benchmark problem for system sizes ranging from 500 to 100,000,000 atoms on several parallel supercomputers--the nCUBE 2, Intel iPSC/860 and Paragon, and Cray T3D. Comparing the results to the fastest reported vectorized Cray Y-MP and C90 algorithm shows that the current generation of parallel machines is competitive with conventional vector supercomputers even for small problems. For large problems, the spatial algorithm achieves parallel efficiencies of 90% and a 1840-node Intel Paragon performs up to 165 faster than a single Cray C9O processor. Trade-offs between the three algorithms and guidelines for adapting them to more complex molecular dynamics simulations are also discussed.

29,323 citations

01 Jan 2016
TL;DR: The using multivariate statistics is universally compatible with any devices to read, allowing you to get the most less latency time to download any of the authors' books like this one.
Abstract: Thank you for downloading using multivariate statistics. As you may know, people have look hundreds times for their favorite novels like this using multivariate statistics, but end up in infectious downloads. Rather than reading a good book with a cup of tea in the afternoon, instead they juggled with some harmful bugs inside their laptop. using multivariate statistics is available in our digital library an online access to it is set as public so you can download it instantly. Our books collection saves in multiple locations, allowing you to get the most less latency time to download any of our books like this one. Merely said, the using multivariate statistics is universally compatible with any devices to read.

14,604 citations

Journal ArticleDOI
01 Apr 1988-Nature
TL;DR: In this paper, a sedimentological core and petrographic characterisation of samples from eleven boreholes from the Lower Carboniferous of Bowland Basin (Northwest England) is presented.
Abstract: Deposits of clastic carbonate-dominated (calciclastic) sedimentary slope systems in the rock record have been identified mostly as linearly-consistent carbonate apron deposits, even though most ancient clastic carbonate slope deposits fit the submarine fan systems better. Calciclastic submarine fans are consequently rarely described and are poorly understood. Subsequently, very little is known especially in mud-dominated calciclastic submarine fan systems. Presented in this study are a sedimentological core and petrographic characterisation of samples from eleven boreholes from the Lower Carboniferous of Bowland Basin (Northwest England) that reveals a >250 m thick calciturbidite complex deposited in a calciclastic submarine fan setting. Seven facies are recognised from core and thin section characterisation and are grouped into three carbonate turbidite sequences. They include: 1) Calciturbidites, comprising mostly of highto low-density, wavy-laminated bioclast-rich facies; 2) low-density densite mudstones which are characterised by planar laminated and unlaminated muddominated facies; and 3) Calcidebrites which are muddy or hyper-concentrated debrisflow deposits occurring as poorly-sorted, chaotic, mud-supported floatstones. These

9,929 citations

Journal ArticleDOI
28 Jan 2000-Science
TL;DR: The tensile strengths of individual multiwalled carbon nanotubes (MWCNTs) were measured with a "nanostressing stage" located within a scanning electron microscope and a variety of structures were revealed, such as a nanotube ribbon, a wave pattern, and partial radial collapse.
Abstract: The tensile strengths of individual multiwalled carbon nanotubes (MWCNTs) were measured with a “nanostressing stage” located within a scanning electron microscope. The tensile-loading experiment was prepared and observed entirely within the microscope and was recorded on video. The MWCNTs broke in the outermost layer (“sword-in-sheath” failure), and the tensile strength of this layer ranged from 11 to 63 gigapascals for the set of 19 MWCNTs that were loaded. Analysis of the stress-strain curves for individual MWCNTs indicated that the Young's modulus E of the outermost layer varied from 270 to 950 gigapascals. Transmission electron microscopic examination of the broken nanotube fragments revealed a variety of structures, such as a nanotube ribbon, a wave pattern, and partial radial collapse.

5,011 citations