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Paul Bowen

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Publications associées (94)

cemff: A force field database for cementitious materials including validations, applications and opportunities

Paul Bowen, Sandra Caroline Galmarini, Aslam Kunhi Mohamed, David Geissbühler

This paper reviews atomistic force field parameterizations for molecular simulations of cementitious minerals, such as tricalcium silicate (C3S), portlandite (CH), tobermorites (model C-S-H). Computational techniques applied to these materials include clas ...

Pergamon-Elsevier Science Ltd2017

Comparison of apparent activation energies for densification of alumina powders by pulsed electric current sintering (spark plasma sintering) and conventional sintering-toward applications for transparent polycrystalline alumina

Paul Bowen, Claude Paul Carry, Michael Stuer, Zhe Zhao

In the quest for high real in-line transmittances for transparent polycrystalline alumina (PCA), we need defect free processing. One of the biggest advances in producing high density defect free ceramics over recent years has been the advent of spark plasm ...

Materials Research Society2017

Grain boundary complexion and transparent polycrystalline alumina from an atomistic simulation perspective

Paul Bowen, Abhishek Tewari

Transparent alumina is often processed with sintering additives such as, Y, La, and Mg, in order to limit its grain growth at high sintering temperatures. Usually, these additives segregate to the grain boundaries due to their larger cationic size than Al ...

Elsevier2016

Pro-oxidant effects of nano-TiO2 on Chlamydomonas reinhardtii during short-term exposure

Paul Bowen, Christian Santschi, Olivier Martin, Lionel André Maurizi, Volodymyr Koman, Nadia Rachel Von Moos, Amarnath Jayaprakash

This study sheds light on the short-term dynamics of pro-oxidant processes related to the exposure of C. reinhardtii microalgae to nano-TiO2 using (a) conventional fluorescence probes for cellular pro-oxidant process and (b) a recently developed cytochrome ...

Royal Soc Chemistry2016

Predicting the yield stress of paraffin-wax suspensions

Paul Bowen

An empirical modification of the Yodel model was developed for the prediction of the yield stress of concentrated, particulate, paraffin-wax suspensions, with a solids loading in the range of 47-57 vol.%, used in the low-pressure injection moulding (LPIM). ...

Elsevier2016

New approach to low thermal conductivity of thermal barrier protection with improved mechanical integrity

Paul Bowen, Heinrich Hofmann, Abhishek Tewari

Layered ceramic systems with designed stacks of dense and porous layers were investigated as alternative for thermal barrier protection system (TBPs). This approach gives the possibility to obtain low thermal conductivity with the impact protection of dens ...

Elsevier2016

Atomistic Simulations of Silicate Species Interaction with Portlandite Surfaces

Paul Bowen, Sandra Caroline Galmarini, Aslam Kunhi Mohamed

Portlandite (Ca(OH)(2), CH) is the second most abundant hydrate formed in the reaction of Portland cement with water, making it an important component in the built environment. Formation of CH is closely linked to the growth of the main hydrate phase, calc ...

American Chemical Society2016

Physicochemical Characterization of Nebulized Superparamagnetic Iron Oxide Nanoparticles (SPIONs)

Paul Bowen, Géraldine Sylvie Coullerez, Louise Catherine Bryan, Guillaume Suarez

Background: Aerosol-mediated delivery of nano-based therapeutics to the lung has emerged as a promising alternative for treatment and prevention of lung diseases. Superparamagnetic iron oxide nanoparticles (SPIONs) have attracted significant attention for ...

Mary Ann Liebert, Inc2015

How colloid-colloid interactions and hydrodynamic effects influence the percolation threshold: A simulation study in alumina suspensions

Paul Bowen

The percolation behavior of alumina suspensions is studied by computer simulations. The percolation threshold phi(c), is calculated, determining the key factors that affect its magnitude: the strength of colloid-colloid attraction and the presence of hydro ...

Elsevier2015

Continuous Polyol Synthesis of Metal and Metal Oxide Nanoparticles Using a Segmented Flow Tubular Reactor (SFTR)

Paul Bowen, Andrea Testino, Christoph Stähli, Jose Enrico Quijano Quinsaat, Frank Pilger

Over the last years a new type of tubular plug flow reactor, the segmented flow tubular reactor (SFTR), has proven its versatility and robustness through the water-based synthesis of precipitates as varied as CaCO3, BaTiO3, Mn((1-x))Ni(x)C(2)O(4)2H(2)O, YB ...

Molecular Diversity Preservation International2015

Surface 3D Micro Free Forms: Multifunctional Microstructured Mesoporous alpha-Alumina by in Situ Slip Casting Using Excimer Laser Ablated Polycarbonate Molds

Paul Bowen, Patrik Willi Hoffmann, Sriharitha Rowthu

Ceramic surface microstructuring is a rapidly growing field with a variety of applications in tribology, wetting, biology, and so on. However, there are limitations to large-area microstructuring and fabrication of three-dimensional (3D) micro free forms. ...

Amer Chemical Soc2015

Toward Knowledge-Based Grain-Boundary Engineering of Transparent Alumina Combining Advanced TEM and Atomistic Modeling

Paul Bowen, Marco Cantoni, Michael Stuer, Cécile Hébert, Abhishek Tewari, Farhang Nabiei

Transition element dopants (e.g., Y, La) are commonly used as sintering aids in polycrystalline alumina ceramics, which segregate to the grain boundaries and control the grain-boundary mobility. However, due to the extremely thin (

Wiley-Blackwell2015

Bioavailability of inorganic nanoparticles to planktonic bacteria and aquatic microalgae in freshwater

Paul Bowen, Nadia Rachel Von Moos

Over the past few years, engineered nanomaterials (ENMs) have penetrated nearly every sector of modern life and their broad-scale use is steadily and rapidly increasing. The (expected) elevated levels of ENMs in the environment raise concerns with regard t ...

Royal Soc Chemistry2014

Continuous Production of Tailored Silver Nanoparticles by Polyol Synthesis and Reaction Yield Measured by X-ray Absorption Spectroscopy: Toward a Growth Mechanism

Paul Bowen, Heinrich Hofmann, Frank Nüesch, Andrea Testino, Christian Ludwig, Jose Enrico Quijano Quinsaat

Two complementary topics are discussed: (i) the continuous production of silver nanoparticles (AgNPs) and (ii) the measurement of reaction yield by X-ray absorption near-edge spectroscopy (XANES). The continuous polyol synthesis of AgNPs in grams amount an ...

Amer Chemical Soc2014

Segregation of anion (Cl−) impurities at transparent polycrystalline α-alumina interfaces

Paul Bowen, Marco Cantoni, Cécile Hébert, Abhishek Tewari, Farhang Nabiei

Small amounts of anion impurities (e.g. Cl), which are incorporated during the synthesis of ceramic powders, can affect the properties and microstructure of the final sintered ceramic. The effect of anion impurities is a little studied and poorly understoo ...

Elsevier Sci Ltd2014

Atomistic Modeling of Effect of Mg on Oxygen Vacancy Diffusion in alpha-Alumina

Paul Bowen, Ulrich Aschauer, Abhishek Tewari

Oxygen diffusion plays an important role in grain growth and densification during the sintering of alumina ceramics and governs high-temperature processes such as creep. The atomistic mechanism for oxygen diffusion in alumina is, however, still debated; at ...

Wiley-Blackwell2014

Changes in portlandite morphology with solvent composition: Atomistic simulations and experiment (vol 41, pg 1330, 2011)

Paul Bowen, Sandra Caroline Galmarini, Nicolas Ruffray

Pergamon-Elsevier Science Ltd2014

Influence of Y and La Additions on Grain Growth and the Grain-Boundary Character Distribution of Alumina

Paul Bowen, Michael Stuer, Zhe Zhao

Grain-boundary character distributions (GBCDs) were determined for spark plasma sintered Y- and La-doped aluminas prepared at temperatures between 1450 degrees C and 1600 degrees C. La doping leads to grain boundaries that adopt (0001) orientations 3.7 tim ...

Wiley-Blackwell2014

Colloidal Processing and Yield Stress Modeling Towards Dry Pressed Green Bodies for Transparent Polycrystalline Alumina

Paul Bowen, Michael Stuer

Colloidal processing is a key aspect in modern ceramic processing but most formulations are found empirically. The need for a better knowledge based design of suspension formulation can be achieved by using interparticle potential modelling linked to rheol ...

Wiley-Blackwell2014

Yield stress modelling of doped alumina suspensions for applications in freeze granulation: towards dry pressed transparent ceramics

Paul Bowen, Michael Stuer

Rheology of powder suspensions is a key factor in many processing routes, and better understanding of the parameters that control the rheology improves technical progress by reducing the empirical factors in the formulation of powder slurries. The strict r ...

2012

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