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Paul Bowen

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Related publications (92)

Page 1 of 5

Synthesis and characterization of fluorinated anatase nanoparticles and subsequent N-doping for efficient visible light activated photocatalysis

Paul Bowen, Sami Rtimi, Irena Markovic

Fluorinated-titanium dioxide (TiO2-F) nanoparticles in a pure anatase polymorph was precipitated from solution by hydrolysis of titanium oxychloride, using urea and ammonia as precipitation agents and potassium fluoride as a source of fluorine anion. A fur ...

2018

Yodel: A Yield Stress Model for Suspensions

Paul Bowen

A model for the yield stress of particulate suspensions is presented that incorporates microstructural parameters taking into account volume fraction of solids, particle size, particle size distribution, maximum packing, percolation threshold, and interpar ...

2006

Global uncertainty-sensitivity analysis on mechanistic kinetic models: From model assessment to theory-driven design of nanoparticles

Paul Bowen, Andrea Testino, Agnese Carino, Mohammad Reza Andalibi

Recently, we developed a population balance framework describing the precipitation of calcium-silicate-hydrate, a key nanomaterial in the construction industry and with potential applications in biomedicine, environmental remediation, and catalysis. In thi ...

2020

Adsorption Free Energy of Single Amino Acids at the Rutile (110)/ Water Interface Studied by Well-Tempered Metadynamics

Paul Bowen, Ulrich Aschauer, Azade Yazdan Yar

Single amino acids are present in blood plasma and are the building blocks of larger organic residues. Their interaction with surfaces is therefore crucial for biomedical applications in contact with blood. In this work, we use well-tempered metadynamics t ...

2018

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

Paul Bowen, Andrea Testino, 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

Thermal stability of nanometric TiC-carbon composites: effects of carbon allotropes and Zr milling impurities

Paul Bowen

In the ISOL (Isotope Separator OnLine) method a target at high temperatures (up to 2300 degrees C), is bombarded with high energy protons in order to produce isotopes through nuclear reactions which are simultaneously extracted from the target, ionized and ...

2018

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

Thermodynamic-Kinetic Precipitation Modeling. A Case Study: The Amorphous Calcium Carbonate (ACC) Precipitation Pathway Unravelled

Paul Bowen, Andrea Testino, Christian Ludwig, Frank Pilger, Agnese Carino, Mohammad Reza Andalibi

Nine accurate experimental data sets on amorphous calcium carbonate (ACC) formation in dilute solution were collected varying temperature and pH. The entire precipitation process is described using a complete thermodynamic-kinetic model. The thermodynamic ...

American Chemical Society2017

Colloidal processing and sintering of nanosized transition aluminas

Paul Bowen, Heinrich Hofmann

The dispersion of nanosized gamma aluminas with high specific surfaces areas (100 m2 /g) and primary particle sizes around 20 nm, using polyacrylic acid, has been investigated. The effect of pH and polymer concentration showed that the highest density gree ...

2005

Non-invasive continuous monitoring of pro-oxidant effects of engineered nanoparticles on aquatic microorganisms

Paul Bowen, Christian Santschi, Olivier Martin, Volodymyr Koman, Nadia Rachel Von Moos

Engineered nanomaterials (ENMs) are key drivers for the development of highly sophisticated new technologies. As all new attainments, the rapidly increasing used of ENMs raise concerns about their safety for the environment and humans. There is growing evi ...

2017

The Atomic-Level Structure of Cementitious Calcium Aluminate Silicate Hydrate

Paul Bowen, Karen Scrivener, Aslam Kunhi Mohamed, Jirawan Siramanont, David Lyndon Emsley, Brennan James Walder, Maya Nicole Harris, Pierrick Berruyer, Pinelopi Moutzouri, Mattia Negroni

Despite use of blended cements containing significant amounts of aluminum for over 30 years, the structural nature of aluminum in the main hydration product, calcium aluminate silicate hydrate (C-A-S-H), remains elusive. Using first-principles calculations ...

2020

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

Porous granules by freeze granulation of Pickering emulsions stabilized with halloysite particles

Paul Bowen

Pickering emulsions stabilized with a natural silicate mineral, halloysite, were dried by freeze granulation in order to prepare porous granules. Different formulations were studied, by varying the pH of the suspension, the ionic strength and with the addi ...

ELSEVIER2020

Towards an improved understanding of the β-TCP crystal structure by means of “checkerboard” atomistic simulations

Paul Bowen, Duncan Thomas Lindsay Alexander, Gabrielle Anne Laguisma Sblendorio

The large variability of biological responses to beta-TCP implants reported in the literature could possibly be related to subtle differences in the beta-TCP crystal structure. The structure contains one partially occupied site Ca(4). In order to better un ...

2023

Interactions of Tris with rutile surfaces and consequences for in vitro bioactivity testing

Paul Bowen, Ulrich Aschauer

Tris(hydroxymethyl)aminomethane (Tris) has been used as the buffer in bioactivity testing for over two decades and has become a standard choice for the scientific community. While it is believed to be non-interacting, the extent of its interactions with ti ...

Elsevier2021

Atomic-Level Structure of Zinc-Modified Cementitious Calcium Silicate Hydrate

Paul Bowen, Karen Scrivener, Manuel Cordova, David Lyndon Emsley, Anna Morales Melgares, Pinelopi Moutzouri, Ziga Casar, Amrit Venkatesh

It has recently been demonstrated that the addition of zinc can enhance the mechanical strength of tricalcium silicates (C3S) upon hydration, but the structure of the main hydration product of cement, calcium silicate hydrate (C-S-H), in zinc modified form ...

AMER CHEMICAL SOC2022

The Atomic-Level Structure of Cementitious Calcium Silicate Hydrate

Paul Bowen, Karen Scrivener, Aslam Kunhi Mohamed, Abhishek Kumar, David Lyndon Emsley, Aaron James Rossini, Albert Hofstetter, Brennan James Walder

Efforts to tune the bulk physical properties of concrete are hindered by a lack of knowledge related to the atomic-level structure and growth of calcium silicate hydrate phases, which form about 50-60% by volume of cement paste. Here we describe the first ...

2017

Adsorption of Superplasticizers on a Model Powder

Paul Bowen, François Perche

Adsorption isotherms of carboxylate type superplasticizers with different architectures have been measured on MgO considered as a non-reactive model powder. This system allowed us to study the influence of pH, electrolyte type, concentration and ionic stre ...

Conseil national de recherches du Canada2007

Surface properties of clinker phases and clay minerals characterized by inverse gas chromatography (IGC) and their link to reactivity

Paul Bowen, Karen Scrivener, Franco Alberto Zunino Sommariva

This paper presents a preliminary study of the characterization of the surface energy properties of clinker phases (C3S and C3A), kaolin and metakaolin by Inverse Gas Chromatography (IGC). For this, a reliable measurement methodology was developed. By look ...

Pergamon-Elsevier Science Ltd2024

Effect of minor amounts of beta-calcium pyrophosphate and hydroxyapatite on the physico-chemical properties and osteoclastic resorption of beta-tricalcium phosphate cylinders

Paul Bowen, Gabrielle Anne Laguisma Sblendorio

beta-Tricalcium Phosphate (beta-TCP), one of the most used bone graft substitutes, may contain up to 5 wt% foreign phase according to standards. Typical foreign phases include beta-calcium pyrophosphate (beta-CPP) and hydroxyapatite (HA). Currently, the ef ...

KEAI PUBLISHING LTD2022