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Surfaces, Microstructure and Fracture Group

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This series replaces PCS Fracture and Shock Physics. Livestream using Teams. Meeting ID: 394 909 515 655 . Passcode: jpqqaf
Updated: 25 sec ago

Thu 09 Mar 15:00: Ultrafast diffusion at the onset of 2D growth: O/Ru(0001) and S/Ni(111)

Mon, 14/11/2022 - 16:36
Ultrafast diffusion at the onset of 2D growth: O/Ru(0001) and S/Ni(111)

The mechanisms that underpin growth at surfaces are of increasing interest as 2D materials are explored for applications. Here, I present an experimental study of clustering dynamics observed during ultrafast surface motion, measured using helium-3 spin echo (HeSE) spectroscopy. I will discuss two systems that exhibit islanding phenomena, namely O/Ru(0001) and S/Ni(111); each is measured at high temperatures, corresponding to picosecond-timescale diffusion which has been inaccessible using past techniques

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Thu 09 Feb 15:00: Experimental and numerical study of detonation reaction zones

Wed, 09/11/2022 - 10:59
Experimental and numerical study of detonation reaction zones

The chemical reaction zone is the region in a detonating explosive between the initial pressure spike and the sonic locus. Its length is affected by the properties of the explosive, and in some circumstances is difficult to determine experimentally. The reaction zone of one explosive (PETN) was measured using a capacitative sensing technique, and the results were used to develop a reactive hydrocode.

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Thu 17 Nov 15:00: Fundamentals of thermodynamics (and a bit of quantum mechanics)

Wed, 26/10/2022 - 17:38
Fundamentals of thermodynamics (and a bit of quantum mechanics)

Five years ago I attempted to talk about a somewhat new approach to thermodynamics at an SMF seminar. This seminar is aimed are presenting ‘round 2’ where hopefully some of the key arguments are clarified. Given thermodynamics is based on the quantum mechanical behaviour of the world, one ends up looking at the fundamental principles of QM for ‘the reason why’, and this seminar proposes a way of approaching the basis of QM that just starts from the notion that there are waves that obey linear superposition and that there is a time development operator.

Join on your computer, mobile app or room device Click here to join the talk online Meeting ID: 394 909 515 655 Passcode: jpqqaf

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Thu 20 Oct 15:00: Resonant acoustic mixing processing studies of energetic materials

Mon, 10/10/2022 - 14:11
Resonant acoustic mixing processing studies of energetic materials

Join on your computer, mobile app or room device Click here to join the talk online Meeting ID: 394 909 515 655 Passcode: jpqqaf

An investigation into how the efficiency (time and energy required for homogeneity) of Resonant Acoustic Mixing (RAM) can be determined and optimised was undertaken. An idealised Polymer Bonded eXplosive (PBX) simulant based on glass microbeads (28.3 µm D50 , 62 v/v in binder and plasticiser) was used for mixing. Mixing evolution was monitored using machine output data, whereby the mixer ‘intensity’ (related to power draw) was plotted against time. Experiments were undertaken with three acceleration settings, two mixer units, and three vessel materials of low, medium, and high surface free energy. Different stages of the mixer ‘intensity’ profiles were found to correspond to discrete stages of mixing, as well as further rheological changes due to continued frictional heating, thus viscosity reduction, beyond homogeneity being achieved. Time to mixing completion was found to be repeatable within a standard deviation of ±10 , strongly dependant on acceleration setting, and additionally dependant on vessel material, though additional data is required to confirm this. A significant difference in mixing time was observed between different LabRAM units. Partial vacuum application without degassing was beneficial for mixing. Finally, a paradigm linking the ‘movement modes’ of mixing was constructed, based on literature observations and the experimental results.

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Thu 24 Nov 15:00: Additive manufacturing of energetic materials

Mon, 03/10/2022 - 13:34
Additive manufacturing of energetic materials

Additive manufacturing (AM) is a fast-growing technology area with many potential benefits in the field of energetic materials. In this talk, the application of extrusion based AM techniques to polymer bonded explosives (PBX) will be discussed, with a particular emphasis on how the properties of a given material interact with those techniques.

Join on your computer, mobile app or room device Click here to join the talk online Meeting ID: 394 909 515 655 Passcode: jpqqaf

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Thu 17 Nov 15:00: Thermodynamics and statistical physics

Sun, 02/10/2022 - 18:29
Thermodynamics and statistical physics

Join on your computer, mobile app or room device Click here to join the talk online Meeting ID: 394 909 515 655 Passcode: jpqqaf

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Thu 10 Nov 15:00: A day in the life of an adsorbate: Observing dynamics in an open quantum system

Sun, 02/10/2022 - 18:29
A day in the life of an adsorbate: Observing dynamics in an open quantum system

Surface adsorbates represent a unique arena in which fundamental processes can be observed at an atomic level. The helium spin-echo method (HeSE), developed largely at the Cavendish, has revealed how surface atoms, and molecules, interact with each other and with the heat-bath provided by the substrate. In addition, dynamical behaviour can often be used to identify single- or multiple-adsorption sites within a single unit cell and provide exquisite detail on energy landscapes. The seminar will present some of the major observations and highlight the extent to which our knowledge of the underlying processes has been clarified.

Join on your computer, mobile app or room device Click here to join the talk online Meeting ID: 394 909 515 655 Passcode: jpqqaf

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Thu 03 Nov 15:00: Cleaning up the nuclear legacy: Vitrified wasteform development and durability

Sun, 02/10/2022 - 18:28
Cleaning up the nuclear legacy: Vitrified wasteform development and durability

Radioactive wastes arising from the nuclear industry need to be immobilised to enable their safe storage and (eventual) disposal. Vitrification of such wastes offers some major benefits, including significant volume reduction which reduces storage and disposal costs. In the UK vitrification of high level wastes has been implemented and vitrification is being considered for a range of intermediate level wastes arising from decommissioning; I will briefly review some of our work in this area including the development of glasses for the vitrification of sludges and ion exchange resins. Understanding the interactions of vitrified wasteforms with water over very extended timescales is an important aspect of such development. Therefore I will also consider the insights we gain from (accelerated) testing, using both powder and monolith tests, of vitrified products, as well as comparisons with the behaviour of natural and anthropogenic analogue glasses.

Join on your computer, mobile app or room device Click here to join the talk online Meeting ID: 394 909 515 655 Passcode: jpqqaf

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Thu 20 Oct 15:00: Resonant acoustic mixing processing studies of energetic materials

Sun, 02/10/2022 - 18:28
Resonant acoustic mixing processing studies of energetic materials

Join on your computer, mobile app or room device Click here to join the talk online Meeting ID: 394 909 515 655 Passcode: jpqqaf

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Thu 13 Oct 15:00: An experimental approach for the validation and development of Group Interaction Modelling for polymer properties

Thu, 29/09/2022 - 23:13
An experimental approach for the validation and development of Group Interaction Modelling for polymer properties

Group Interaction Modelling is a model framework for predicting bulk properties of polymers from their chemical structure and configuration. My research involves using a variety of experimental techniques and conditions to measure relevant polymer properties. The performance of Group Interaction Modelling in predicting these properties is assessed and improvements are identified. In my presentation I will highlight my key findings to date and use examples to demonstrate the predictive power of Group Interaction Modelling in different contexts.

Join on your computer, mobile app or room device Click here to join the talk online Meeting ID: 394 909 515 655 Passcode: jpqqaf

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Thu 24 Nov 15:00: Additive manufacturing of energetic materials

Tue, 27/09/2022 - 16:00
Additive manufacturing of energetic materials

Additive manufacturing (AM) is a fast-growing technology area with many potential benefits in the field of energetic materials. In this talk, the application of extrusion based AM techniques to polymer bonded explosives (PBX) will be discussed, with a particular emphasis on how the properties of a given material interact with those techniques.

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Thu 13 Oct 15:00: An experimental approach for the validation and development of Group Interaction Modelling for polymer properties

Tue, 27/09/2022 - 13:58
An experimental approach for the validation and development of Group Interaction Modelling for polymer properties

Group Interaction Modelling is a model framework for predicting bulk properties of polymers from their chemical structure and configuration. My research involves using a variety of experimental techniques and conditions to measure relevant polymer properties. The performance of Group Interaction Modelling in predicting these properties is assessed and improvements are identified. In my presentation I will highlight my key findings to date and use examples to demonstrate the predictive power of Group Interaction Modelling in different contexts.

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Thu 20 Oct 15:00: Resonant acoustic mixing processing studies of energetic materials

Tue, 27/09/2022 - 13:58
Resonant acoustic mixing processing studies of energetic materials

Abstract not available

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Thu 03 Nov 15:00: Cleaning up the nuclear legacy: Vitrified wasteform development and durability

Tue, 27/09/2022 - 13:58
Cleaning up the nuclear legacy: Vitrified wasteform development and durability

Radioactive wastes arising from the nuclear industry need to be immobilised to enable their safe storage and (eventual) disposal. Vitrification of such wastes offers some major benefits, including significant volume reduction which reduces storage and disposal costs. In the UK vitrification of high level wastes has been implemented and vitrification is being considered for a range of intermediate level wastes arising from decommissioning; I will briefly review some of our work in this area including the development of glasses for the vitrification of sludges and ion exchange resins. Understanding the interactions of vitrified wasteforms with water over very extended timescales is an important aspect of such development. Therefore I will also consider the insights we gain from (accelerated) testing, using both powder and monolith tests, of vitrified products, as well as comparisons with the behaviour of natural and anthropogenic analogue glasses.

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Thu 10 Nov 15:00: A day in the life of an adsorbate: Observing dynamics in an open quantum system

Tue, 27/09/2022 - 13:58
A day in the life of an adsorbate: Observing dynamics in an open quantum system

Surface adsorbates represent a unique arena in which fundamental processes can be observed at an atomic level. The helium spin-echo method (HeSE), developed largely at the Cavendish, has revealed how surface atoms, and molecules, interact with each other and with the heat-bath provided by the substrate. In addition, dynamical behaviour can often be used to identify single- or multiple-adsorption sites within a single unit cell and provide exquisite detail on energy landscapes. The seminar will present some of the major observations and highlight the extent to which our knowledge of the underlying processes has been clarified.

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Thu 17 Nov 15:00: Thermodynamics and statistical physics

Tue, 27/09/2022 - 13:58
Thermodynamics and statistical physics

Abstract not available

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Thu 24 Nov 15:00: Additive manufacturing of energetic materials

Tue, 27/09/2022 - 13:58
Additive manufacturing of energetic materials

Abstract not available

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Thu 13 Oct 15:00: An experimental approach for the validation and development of Group Interaction Modelling for polymer properties

Fri, 23/09/2022 - 11:35
An experimental approach for the validation and development of Group Interaction Modelling for polymer properties

Group Interaction Modelling is a model framework for predicting bulk properties of polymers from their chemical structure and configuration. My research involves using a variety of experimental techniques and conditions to measure relevant polymer properties. The performance of Group Interaction Modelling in predicting these properties is assessed and improvements are identified. In my presentation I will highlight my key findings to date and use examples to demonstrate the predictive power of Group Interaction Modelling in different contexts.

Add to your calendar or Include in your list

Thu 20 Oct 15:00: Resonant acoustic mixing processing studies of energetic materials

Fri, 23/09/2022 - 11:31
Resonant acoustic mixing processing studies of energetic materials

Abstract not available

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Thu 03 Nov 15:00: Cleaning up the nuclear legacy: Vitrified wasteform development and durability

Mon, 12/09/2022 - 17:53
Cleaning up the nuclear legacy: Vitrified wasteform development and durability

Radioactive wastes arising from the nuclear industry need to be immobilised to enable their safe storage and (eventual) disposal. Vitrification of such wastes offers some major benefits, including significant volume reduction which reduces storage and disposal costs. In the UK vitrification of high level wastes has been implemented and vitrification is being considered for a range of intermediate level wastes arising from decommissioning; I will briefly review some of our work in this area including the development of glasses for the vitrification of sludges and ion exchange resins. Understanding the interactions of vitrified wasteforms with water over very extended timescales is an important aspect of such development. Therefore I will also consider the insights we gain from (accelerated) testing, using both powder and monolith tests, of vitrified products, as well as comparisons with the behaviour of natural and anthropogenic analogue glasses.

Add to your calendar or Include in your list