There is, I think, something ethereal about i —the square root of minus one. I remember first hearing about it at school. It seemed an odd beast at that time—an intruder hovering on the edge of reality.

Usually familiarity dulls this sense of the bizarre, but in the case of i it was the reverse: over the years the sense of its surreal nature intensified. It seemed that it was impossible to write mathematics that described the real world in …

I and i

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.

Fast parallel algorithms for short-range molecular dynamics

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

Phd by thesis

J. Appl. Cryst.の発刊に際して

On the significance of the H/E ratio in wear control: a nanocomposite coating approach to optimised tribological behaviour

Thin hard coatings deposited by physical vapour deposition (PVD) techniques are widely used to reduce wear and corrosion of tools and engineering components. Corresponding to the broad range of different modifications of PVD methods, results published on the interrelationships between process parameters and resulting microstructure and properties are not always comparable since system-depending process parameters are often used to describe the growth conditions. System-independent growth parameters like particle energy of flux density may serve as a basis for the comparison of coatings deposited employing different deposition machines and techniques. The aim of this work is to verify the concept of system-independent parameters using different sputtering systems and the coating systems TiN and TiB 2 .

Internal growth parameters : a suitable basis for comparison of PVD coatings

Hard coatings deposited by plasma-assisted vapor deposition methods based on the transition metal nitrides are nowadays widely applied to reduce wear and corrosion of tools. In the last two decades, tremendous advances have been achieved in the development of deposition and application technology of these coatings. The methods to be applied to optimize coating properties are known from materials science, however, only in the last few years significant attempts have been made to use them for designing coatings showing the properties required. In particular, plasma-assisted vapor deposition processes are ideally suited to control the microstructure and composition of hard coatings. Coatings deposited by these processes are often in a non-equilibrium state, e.g., characterized by high compressive stresses, small grain sizes in the nanometer range, or metastable phases, which determine their unique properties like superhardness, toughness, or low friction. The aim of this paper is to present and discuss several mechanisms of hardness enhancement in single-phase and multi-phase coatings based on transition metal nitrides, carbides and borides. These hardening effects include the role of strain hardening by high defect densities obtained by high-energy ion irradiation during deposition, grain size refinement to the nano-scale, solid-solution hardening by alloying elements, and age-hardening by coherent domains. Special emphasis will be laid on the magnitude of these effects in determining coating hardness and on their thermal stability.

Design of Nanostructured Hard Coatings for Optimum Performance

Arc-produced short-length multi-walled carbon nanotubes as “millstones” for the preparation of graphene-like nanoplatelets

Correlation of mechanical damage and electrical behavior of Al/Mo bilayers subjected to bending

A coated metal article such as, e.g., a tool, which article comprises a body part comprising a substantially carbon-free precipitation-hardened iron-cobalt-molybdenum/tungsten-nitrogen alloy and carries a coating. The coating has been applied by a PVD method and/or a CVD method and comprises a substantially single-phase crystalline, cubic face-centered structure. This abstract is neither intended to define the invention disclosed in this specification nor intended to limit the scope of the invention in any way.

Christian Mitterer

Papers

Internal growth parameters : a suitable basis for comparison of PVD coatings

Design of Nanostructured Hard Coatings for Optimum Performance

Arc-produced short-length multi-walled carbon nanotubes as “millstones” for the preparation of graphene-like nanoplatelets

Correlation of mechanical damage and electrical behavior of Al/Mo bilayers subjected to bending

Tool with a coating