Lawrence Murr - Academia.edu (original) (raw)

Papers by Lawrence Murr

Research paper thumbnail of The role of the electron microscope in the cold fusion controversy

Proceedings, annual meeting, Electron Microscopy Society of America

More than two years ago, thousands of scientists around the world raced to confirm the claims of ... more More than two years ago, thousands of scientists around the world raced to confirm the claims of electrochemically induced fusions especially in the palladium/deuterium system. Interestingly enough, it was also claimed during the 1920's that ordinary hydrogen absorbed in palladium fuses to form helium.The author has recently argued that a significant feature of the controversy involving palladium electrodes in electrochemical systems where either hydrogen or deuterium absorption is crucial, probably depends strongly on the palladium microstructure. indeed there is no compelling evidence that has involved a systematic evaluation of the palladium metallurgy or specific microstructural alterations which may have been correlated with heat generation or other fusion-related phenomena.

Research paper thumbnail of Comments on: Deformation twins in punched specimens of a 321 steel

Research paper thumbnail of Microstructures in Friction-Stir Welded Dissimilar, Semi-Solid-Cast Magnesium Alloys

Microscopy and Microanalysis

Research paper thumbnail of Understanding Extreme Deformation with Metallography

Microscopy and Microanalysis

Research paper thumbnail of Heat Input and Temperature Distribution in Friction Stir Welding

Journal of Materials Processing & Manufacturing Science

Research paper thumbnail of Collection and characterization of airborne nanoparticulates

Materials Characterization

ABSTRACT This paper describes the use of a thermal precipitation device to collect representative... more ABSTRACT This paper describes the use of a thermal precipitation device to collect representative, airborne nanoparticulates on transmission electron microscope (TEM) grid supports and their characterization using a bright field (BF)–dark field (DF)–selected area electron diffraction (SAED)–energy dispersive spectrometry (EDS) analysis protocol. Two airborne nanoparticulate regimes are illustrated and compared: (1) general nanoparticulates, composed of nanocrystalline aggregates containing from 2 to >1000 individual particles, ranging in size from approximately 1 to 100 nm and (2) complex, branched clusters of amorphous, carbonaceous spherules (containing from 50 to >1000 spherules, which range in size from 10 to 40 nm in diameter) and carbon nanocrystal aggregates containing nanotubes and other polyhedra. Commercial nanoparticulate aggregates of TiO2 and Si3N4 are also observed in the context of characterization standards and the nanotechnology potential for contributing to atmospheric pollutants.

Research paper thumbnail of Temperature coefficient of twin-boundary energy: The determination of stacking-fault energy from the coherent twin-boundary energy in pure F.C.C. metals

Research paper thumbnail of Variations in grain boundary ledge structure with thermo-mechanical treatment in high-purity aluminum

Research paper thumbnail of Synthesis of isomorphous copper-nickel and immiscible copper-niobium materials by shock-compression

Scripta Metallurgica et Materialia

ABSTRACT

Research paper thumbnail of Contrast phenomena and the identification of grain boundary ledges

Research paper thumbnail of Measurement of interfacial energy of adhesion by scanning electron microscopy

Materials Science and Engineering

Research paper thumbnail of The effect of polycrystallinity on the shock wave response of Fe-34.5wt.%Ni and Fe-15wt.%Cr-15wt.%Ni

Materials Science and Engineering

Research paper thumbnail of Biological Response of Next-Generation of 3D Ti-6Al-4V Biomedical Devices Using Additive Manufacturing of Cellular and Functional Mesh Structures

Journal of Biomaterials and Tissue Engineering

ABSTRACT Motivated by the successful fabrication of patient-specific biomedical implants that can... more ABSTRACT Motivated by the successful fabrication of patient-specific biomedical implants that can potentially replace hard tissue (bone), particularly knee and hip stems and large femoral intramedullary rods, using additive manufacturing by electron beam melting (Murr et al. Phil. Trans. R. Soc. A 2010; 22:1999–2032), we describe here the combined efforts of engineering and biological sciences as a systemic approach to study osteoblast functions of 3D mesh arrays with particular focus on pore size and the potential to use 3D fabricated porous biomedical devices for bone healing. First, the interconnecting porous architecture of monolithic mesh arrays was conducive to cellular functions including attachment, proliferation, differentiation, and mineralization. The underlying reason is that the fabricated structure provided a channel for initiation of cell migration and impregnation of the mesh structure by cells and tissue leading to generation of mineralized extracellular matrix by differentiating pre-osteoblasts. Second, a parametric study on the interconnecting pore diameter of mesh arrays indicated that the average pore diameters studied (∼400–800 μm) had no apparent effect on the differentiation and mineralization, and influenced only the proliferation phase. Third, from the biomechanical point of view, the cell-invaded and cell-integrated 3D mesh structure and resulted in the superior formation of tissue.

Research paper thumbnail of A comparison of shaped charge liner cone and recovered jet fragment microstructures to elucidate dynamic recrystallization phenomena

Scripta Metallurgica et Materialia

Research paper thumbnail of EXPLOMET 90 International Conference on Shock-Wave and High-Strain-Rate Phenomena in Materials

... COllftOiie of infortnr'ati'n. .'¢IuOing qqgextno&a... more ... COllftOiie of infortnr'ati'n. .'¢IuOing qqgextno'n% tor r cinu g ttii b 0urden to •a'•n-qton 'eacawariers ie'rvce•. ODrectoraie f' Int.rmt•~on OperatOnsatia eapcort. ... C. Dumont and C Levaillant, CEMEF, Ecoe des Mines dU rdms, Sophia Antipolis, FRANLt L4/1xpIO/L Page 10. ...

Research paper thumbnail of Metallurgical Applications of Shock-Wave and High-Strain-Rate Phenomena Edited by Lawrence E. Murr, Karl P. Staudhammer, and Marc A. Meyers (Volume 52, Mechanical Engineering, edited by L. L. Faulkner and S. B. Menkes, 1986, Marcel Decker)

Research paper thumbnail of Effects of low earth orbit

Amer Sci, May 1, 1993

The effects of low earth orbit on the Long-Duration Exposure Facility (LDEF) spacecraft are repor... more The effects of low earth orbit on the Long-Duration Exposure Facility (LDEF) spacecraft are reported. The LDEF spacecraft was deployed in low earth orbit in 1984 and was retrieved in 1990. The structure and design of LDEF is described. The dose of ionizing radiation received, data obtained, and its effects on the satellite are discussed. Atomic oxygen surface effects, oxygen

Research paper thumbnail of Study of friction stir welded A319 and A413 aluminum casting alloys

Journal of Materials Science, Jul 31, 2005

Cast aluminum alloys A319 and A413 were friction stir welded using a rotating steel screw tool. T... more Cast aluminum alloys A319 and A413 were friction stir welded using a rotating steel screw tool. The cast microstructures were characterized by numerous inclusions or second phase particles which were homogeneously stirred into the weld zone. TEM analysis illustrated the dynamic recrystallization which facilitates the solid-state flow, and digital microhardness measurements through the base metals and the weld zones illustrate

Research paper thumbnail of In vitro biocompatibility studies of fibroblast cells on Ti-Ta alloys : Biomaterials and bioengineering

Materials Transactions Jim, 2002

Research paper thumbnail of Interfacial Energetics in Metal-Metal, Metal-Ceramic, Metal-Semiconductor, and Related Solid-Solid and Liquid-Solid Systems

Research paper thumbnail of The role of the electron microscope in the cold fusion controversy

Proceedings, annual meeting, Electron Microscopy Society of America

More than two years ago, thousands of scientists around the world raced to confirm the claims of ... more More than two years ago, thousands of scientists around the world raced to confirm the claims of electrochemically induced fusions especially in the palladium/deuterium system. Interestingly enough, it was also claimed during the 1920's that ordinary hydrogen absorbed in palladium fuses to form helium.The author has recently argued that a significant feature of the controversy involving palladium electrodes in electrochemical systems where either hydrogen or deuterium absorption is crucial, probably depends strongly on the palladium microstructure. indeed there is no compelling evidence that has involved a systematic evaluation of the palladium metallurgy or specific microstructural alterations which may have been correlated with heat generation or other fusion-related phenomena.

Research paper thumbnail of Comments on: Deformation twins in punched specimens of a 321 steel

Research paper thumbnail of Microstructures in Friction-Stir Welded Dissimilar, Semi-Solid-Cast Magnesium Alloys

Microscopy and Microanalysis

Research paper thumbnail of Understanding Extreme Deformation with Metallography

Microscopy and Microanalysis

Research paper thumbnail of Heat Input and Temperature Distribution in Friction Stir Welding

Journal of Materials Processing & Manufacturing Science

Research paper thumbnail of Collection and characterization of airborne nanoparticulates

Materials Characterization

ABSTRACT This paper describes the use of a thermal precipitation device to collect representative... more ABSTRACT This paper describes the use of a thermal precipitation device to collect representative, airborne nanoparticulates on transmission electron microscope (TEM) grid supports and their characterization using a bright field (BF)–dark field (DF)–selected area electron diffraction (SAED)–energy dispersive spectrometry (EDS) analysis protocol. Two airborne nanoparticulate regimes are illustrated and compared: (1) general nanoparticulates, composed of nanocrystalline aggregates containing from 2 to >1000 individual particles, ranging in size from approximately 1 to 100 nm and (2) complex, branched clusters of amorphous, carbonaceous spherules (containing from 50 to >1000 spherules, which range in size from 10 to 40 nm in diameter) and carbon nanocrystal aggregates containing nanotubes and other polyhedra. Commercial nanoparticulate aggregates of TiO2 and Si3N4 are also observed in the context of characterization standards and the nanotechnology potential for contributing to atmospheric pollutants.

Research paper thumbnail of Temperature coefficient of twin-boundary energy: The determination of stacking-fault energy from the coherent twin-boundary energy in pure F.C.C. metals

Research paper thumbnail of Variations in grain boundary ledge structure with thermo-mechanical treatment in high-purity aluminum

Research paper thumbnail of Synthesis of isomorphous copper-nickel and immiscible copper-niobium materials by shock-compression

Scripta Metallurgica et Materialia

ABSTRACT

Research paper thumbnail of Contrast phenomena and the identification of grain boundary ledges

Research paper thumbnail of Measurement of interfacial energy of adhesion by scanning electron microscopy

Materials Science and Engineering

Research paper thumbnail of The effect of polycrystallinity on the shock wave response of Fe-34.5wt.%Ni and Fe-15wt.%Cr-15wt.%Ni

Materials Science and Engineering

Research paper thumbnail of Biological Response of Next-Generation of 3D Ti-6Al-4V Biomedical Devices Using Additive Manufacturing of Cellular and Functional Mesh Structures

Journal of Biomaterials and Tissue Engineering

ABSTRACT Motivated by the successful fabrication of patient-specific biomedical implants that can... more ABSTRACT Motivated by the successful fabrication of patient-specific biomedical implants that can potentially replace hard tissue (bone), particularly knee and hip stems and large femoral intramedullary rods, using additive manufacturing by electron beam melting (Murr et al. Phil. Trans. R. Soc. A 2010; 22:1999–2032), we describe here the combined efforts of engineering and biological sciences as a systemic approach to study osteoblast functions of 3D mesh arrays with particular focus on pore size and the potential to use 3D fabricated porous biomedical devices for bone healing. First, the interconnecting porous architecture of monolithic mesh arrays was conducive to cellular functions including attachment, proliferation, differentiation, and mineralization. The underlying reason is that the fabricated structure provided a channel for initiation of cell migration and impregnation of the mesh structure by cells and tissue leading to generation of mineralized extracellular matrix by differentiating pre-osteoblasts. Second, a parametric study on the interconnecting pore diameter of mesh arrays indicated that the average pore diameters studied (∼400–800 μm) had no apparent effect on the differentiation and mineralization, and influenced only the proliferation phase. Third, from the biomechanical point of view, the cell-invaded and cell-integrated 3D mesh structure and resulted in the superior formation of tissue.

Research paper thumbnail of A comparison of shaped charge liner cone and recovered jet fragment microstructures to elucidate dynamic recrystallization phenomena

Scripta Metallurgica et Materialia

Research paper thumbnail of EXPLOMET 90 International Conference on Shock-Wave and High-Strain-Rate Phenomena in Materials

... COllftOiie of infortnr'ati'n. .'¢IuOing qqgextno&a... more ... COllftOiie of infortnr'ati'n. .'¢IuOing qqgextno'n% tor r cinu g ttii b 0urden to •a'•n-qton 'eacawariers ie'rvce•. ODrectoraie f' Int.rmt•~on OperatOnsatia eapcort. ... C. Dumont and C Levaillant, CEMEF, Ecoe des Mines dU rdms, Sophia Antipolis, FRANLt L4/1xpIO/L Page 10. ...

Research paper thumbnail of Metallurgical Applications of Shock-Wave and High-Strain-Rate Phenomena Edited by Lawrence E. Murr, Karl P. Staudhammer, and Marc A. Meyers (Volume 52, Mechanical Engineering, edited by L. L. Faulkner and S. B. Menkes, 1986, Marcel Decker)

Research paper thumbnail of Effects of low earth orbit

Amer Sci, May 1, 1993

The effects of low earth orbit on the Long-Duration Exposure Facility (LDEF) spacecraft are repor... more The effects of low earth orbit on the Long-Duration Exposure Facility (LDEF) spacecraft are reported. The LDEF spacecraft was deployed in low earth orbit in 1984 and was retrieved in 1990. The structure and design of LDEF is described. The dose of ionizing radiation received, data obtained, and its effects on the satellite are discussed. Atomic oxygen surface effects, oxygen

Research paper thumbnail of Study of friction stir welded A319 and A413 aluminum casting alloys

Journal of Materials Science, Jul 31, 2005

Cast aluminum alloys A319 and A413 were friction stir welded using a rotating steel screw tool. T... more Cast aluminum alloys A319 and A413 were friction stir welded using a rotating steel screw tool. The cast microstructures were characterized by numerous inclusions or second phase particles which were homogeneously stirred into the weld zone. TEM analysis illustrated the dynamic recrystallization which facilitates the solid-state flow, and digital microhardness measurements through the base metals and the weld zones illustrate

Research paper thumbnail of In vitro biocompatibility studies of fibroblast cells on Ti-Ta alloys : Biomaterials and bioengineering

Materials Transactions Jim, 2002

Research paper thumbnail of Interfacial Energetics in Metal-Metal, Metal-Ceramic, Metal-Semiconductor, and Related Solid-Solid and Liquid-Solid Systems