Multiscale coupling and multiphysics approaches in earth sciences : theory

Measuring Earth material behaviour on time scales of millions of years transcends our current capability in the laboratory. We review an alternative path considering multiscale and multiphysics approaches with quantitative structure-property relationships. This approach allows a sound basis to incorporate physical principles such as chemistry, thermodynamics, diffusion and geometry-energy relations into simulations and data assimilation on the vast range of length and time scales encountered in the Earth. We identify key length scales for Earth systems processes and find a substantial scale separation between chemical, hydrous and thermal diffusion. We propose that this allows a simplified two-scale analysis where the outputs from the micro-scale model can be used as inputs for meso-scale simulations, which then in turn becomes the micro-model for the next scale up. We present two fundamental theoretical approaches to link the scales through asymptotic homogenisation from a macroscopic thermodynamic view and percolation renormalisation from a microscopic, statistical mechanics view.

Entropic bounds for multi-scale and multi-physics coupling in earth sciences

The ability to understand and predict how thermal, hydrological,mechanical and chemical (THMC) processes interact is fundamental to many research initiatives and industrial applications. We present (1) a new Thermal– Hydrological–Mechanical–Chemical (THMC) coupling formulation, based on non-equilibrium thermodynamics; (2) show how THMC feedback is incorporated in the thermodynamic approach; (3) suggest a unifying thermodynamic framework for multi-scaling; and (4) formulate a new rationale for assessing upper and lower bounds of dissipation for THMC processes. The technique is based on deducing time and length scales suitable for separating processes using a macroscopic finite time thermodynamic approach. We show that if the time and length scales are suitably chosen, the calculation of entropic bounds can be used to describe three different types of material and process uncertainties: geometric uncertainties,stemming from the microstructure; process uncertainty, stemming from the correct derivation of the constitutive behavior; and uncertainties in time evolution, stemming from the path dependence of the time integration of the irreversible entropy production. Although the approach is specifically formulated here for THMC coupling we suggest that it has a much broader applicability. In a general sense it consists of finding the entropic bounds of the dissipation defined by the product of thermodynamic force times thermodynamic flux which in material sciences corresponds to generalized stress and generalized strain rates, respectively.

Development of a Remote Sensing Core Curriculum submitted for the sessions on educational initiatives in Geoscience and Remote Sensing

A Remote Sensing Core Curriculum (RSCC) development project is currently underway. This project is being conducted under the auspices of the National Center for Geographic Information and Analysis (NCGIA). RSCC is an outgrowth of the NCGIA GIS Core Curriculum project. It grew out of discussions begun at NCGIA, Initiative 12 (I-12): 'Integration of Remote Sensing and Geographic Information Systems'. This curriculum development project focuses on providing professors, teachers and instructors in undergraduate and graduate institutions with course materials from experts in specific subject matter for areas use in the class room.

Remote sensing utility expansion through Earth Portal internet browser

A modular, graphic-oriented Internet browser has been developed to enable non-technical client access to a literal spinning world of information and remotely sensed. The Earth Portal (www.earthportal.net) uses the ManyOne browser (www.manyone.net) to provide engaging point and click views of the Earth fully tessellated with remotely sensed imagery and geospatial data. The ManyOne browser technology use Mozilla with embedded plugins to apply multiple 3-D graphics engines, e.g. ArcGlobe or GeoFusion, that directly link with the open-systems architecture of the geo-spatial infrastructure. This innovation allows for rendering of satellite imagery directly over the Earth's surface and requires no technical training by the web user. Effective use of this global distribution system for the remote sensing community requires a minimal compliance with protocols and standards that have been promoted by NSDI and other open-systems standards organizations.

Multiscale coupling and multiphysics approaches in earth sciences : applications

Geoscientists are confronted with the challenge of assessing nonlinear phenomena that result from multiphysics coupling across multiple scales from the quantum level to the scale of the earth and from femtoseconds to the 4.5 Ga of history of our planet. We neglect in this review electromagnetic modelling of the processes in the Earth’s core, and focus on four types of couplings that underpin fundamental instabilities in the Earth. These are thermal (T), hydraulic (H), mechanical (M) and chemical (C) processes which are driven and controlled by the transfer of heat to the Earth’s surface. Instabilities appear as faults, folds, compaction bands, shear/fault zones, plate boundaries and convective patterns. Convective patterns emerge from buoyancy overcoming viscous drag at a critical Rayleigh number. All other processes emerge from non-conservative thermodynamic forces with a critical critical dissipative source term, which can be characterised by the modified Gruntfest number Gr. These dissipative processes reach a quasi-steady state when, at maximum dissipation, THMC diffusion (Fourier, Darcy, Biot, Fick) balance the source term. The emerging steady state dissipative patterns are defined by the respective diffusion length scales. These length scales provide a fundamental thermodynamic yardstick for measuring instabilities in the Earth. The implementation of a fully coupled THMC multiscale theoretical framework into an applied workflow is still in its early stages. This is largely owing to the four fundamentally different lengths of the THMC diffusion yardsticks spanning micro-metre to tens of kilometres compounded by the additional necessity to consider microstructure information in the formulation of enriched continua for THMC feedback simulations (i.e., micro-structure enriched continuum formulation). Another challenge is to consider the important factor time which implies that the geomaterial often is very far away from initial yield and flowing on a time scale that cannot be accessed in the laboratory. This leads to the requirement of adopting a thermodynamic framework in conjunction with flow theories of plasticity. This framework allows, unlike consistency plasticity, the description of both solid mechanical and fluid dynamic instabilities. In the applications we show the similarity of THMC feedback patterns across scales such as brittle and ductile folds and faults. A particular interesting case is discussed in detail, where out of the fluid dynamic solution, ductile compaction bands appear which are akin and can be confused with their brittle siblings. The main difference is that they require the factor time and also a much lower driving forces to emerge. These low stress solutions cannot be obtained on short laboratory time scales and they are therefore much more likely to appear in nature than in the laboratory. We finish with a multiscale description of a seminal structure in the Swiss Alps, the Glarus thrust, which puzzled geologists for more than 100 years. Along the Glarus thrust, a km-scale package of rocks (nappe) has been pushed 40 km over its footwall as a solid rock body. The thrust itself is a m-wide ductile shear zone, while in turn the centre of the thrust shows a mm-cm wide central slip zone experiencing periodic extreme deformation akin to a stick-slip event. The m-wide creeping zone is consistent with the THM feedback length scale of solid mechanics, while the ultralocalised central slip zones is most likely a fluid dynamic instability.

Laboratory study on the performance of recycled concrete aggregates blended with reclaimed asphalt pavement as pavement granular material

Production of recycled concrete aggregates (RCA) from construction and demolition (C&D) waste has become popular all over the world since the availability of land spaces are limited to dispose. Therefore it is important to seek alternative applications for RCA. The use of RCA in base and sub-base layers in granular pavement is a viable solution. In mechanistic pavement design, rutting (permanent deformation) is considered as the major failure mechanisms of the pavement. The rutting is the accumulation of permanent deformation of pavement layers caused by the repetitive vehicle load. In Queensland, Australia, it is accepted to have the maximum of 20% of reclaimed asphalt pavement (RAP) in RCA and therefore, it is important to investigate the effect of RAP on the permanent deformation properties of RCA. In this study, a series of repeated load triaxial (RLT) tests were conducted on RCA blended with different percentage of RAP to investigate the permanent deformation and resilient modulus properties of RCA. The vertical deformation and resilient modulus values were used to determine the response of RCA for the cyclic loading under standard pressure and loading conditions.

Assessment of recycled concrete aggregates as a pavement material

Population increase and economic developments can lead to construction as well as demolition of infrastructures such as buildings, bridges, roads, etc resulting in used concrete as a primary waste product. Recycling of waste concrete to obtain the recycled concrete aggregates (RCA) for base and/or sub-base materials in road construction is a foremost application to be promoted to gain economical and sustainability benefits. As the mortar, bricks, glass and reclaimed asphalt pavement (RAP) present as constituents in RCA, it exhibits inconsistent properties and performance. In this study, six different types of RCA samples were subjected classification tests such as particle size distribution, plasticity, compaction test, unconfined compressive strength (UCS) and California bearing ratio (CBR) tests. Results were compared with those of the standard road materials used in Queensland, Australia. It was found that material type ‘RM1-100/RM3-0’ and ‘RM1-80/RM3-20’ samples are in the margin of the minimum required specifications of base materials used for high volume unbound granular roads while others are lower than that the minimum requirement.

Collaborative resource development for energy efficiency education

BACKGROUND There is a growing volume of open source ‘education material’ on energy efficiency now available however the Australian government has identified a need to increase the use of such materials in undergraduate engineering education. Furthermore, there is a reported need to rapidly equip engineering graduates with the capabilities in conducting energy efficiency assessments, to improve energy performance across major sectors of the economy. In January 2013, building on several years of preparatory action-research initiatives, the former Department of Industry, Innovation, Climate Change, Science, Research and Tertiary Education (DIICCSRTE) offered $600,000 to develop resources for energy efficiency related graduate attributes, targeting Engineers Australia college disciplines, accreditation requirements and opportunities to address such requirements. PURPOSE This paper discusses a $430,000 successful bid by a university consortium led by QUT and including RMIT, UA, UOW, and VU, to design and pilot several innovative, targeted open-source resources for curriculum renewal related to energy efficiency assessments, in Australian engineering programs (2013-2014), including ‘flat-pack’, ‘media-bites’, ‘virtual reality’ and ‘deep dive’ case study initiatives. DESIGN/ METHOD The paper draws on literature review and lessons learned by the consortium partners in resource development over the last several years to discuss methods for selecting key graduate attributes and providing targeted resources, supporting materials, and innovative delivery options to assist universities deliver knowledge and skills to develop such attributes. This includes strategic industry and key stakeholders engagement. The paper also discusses processes for piloting, validating, peer reviewing, and refining these resources using a rigorous and repeatable approach to engaging with academic and industry colleagues. RESULTS The paper provides an example of innovation in resource development through an engagement strategy that takes advantage of existing networks, initiatives, and funding arrangements, while informing program accreditation requirements, to produce a cost-effective plan for rapid integration of energy efficiency within education. By the conference, stakeholder workshops will be complete. Resources will be in the process of being drafted, building on findings from the stakeholder engagement workshops. Reporting on this project “in progress” provides a significant opportunity to share lessons learned and take on board feedback and input. CONCLUSIONS This paper provides a useful reference document for others considering significant resource development in a consortium approach, summarising benefits and challenges. The paper also provides a basis for documenting the second half of the project, which comprises piloting resources and producing a ‘good practice guide’ for energy efficiency related curriculum renewal.

The past, present and future of carbon labelling for construction materials – a review

Global climate change is one of the most significant environmental issues that can harm human development. One central issue for the building and construction industry to address global climate change is the development of a credible and meaningful way to measure greenhouse gas (GHG) emissions. While Publicly Available Specification (PAS) 2050, the first international GHG standard, has been proven to be successful in standardizing the quantification process, its contribution to the management of carbon labels for construction materials is limited. With the recent publication of ISO 14067: Greenhouse gases – carbon footprint of products – requirements and guidelines for quantification and communication in May 2013, it is necessary for the building and construction industry to understand the past, present and future of the carbon labelling practices for construction materials. A systematic review shows that international GHG standards have been evolving in terms of providing additional guidance on communication and comparison, as well as less flexibility on the use of carbon labels. At the same time, carbon labelling schemes have been evolving on standardization and benchmarking. In addition, future actions are needed in the aspect of raising consumer awareness, providing benchmarking, ensuring standardization and developing simulation technologies in order for carbon labelling schemes for construction materials to provide credible, accurate and transparent information on GHG emissions.

Teaching fractions to adult learners enrolled in a civil construction course : knowledge, action and materials action in tandem

This paper investigates the teaching and learning of fractions to Indigenous adult learners in a Civil Construction Certificate Course. More specifically it explores why the use of materials is critical to building knowledge and understanding. This focus is important for two reasons. First, it allows for considerations of a trainer’s approach for teaching fractions and, second it provides insights into how adult learners can be supported with representing their practical experiences of fractions to make generalisation thus building on their knowledge and learning experiences. The paper draws on teaching episodes from an Australian Research Council funded Linkage project that investigates how mathematics is taught and learned in Certificate Courses, here, Certificate 11 in Civil Construction. Action research and decolonising methods (Smith, 1999) were used to conduct the research. Video excerpts which feature one trainer and three students are analysed and described. Findings from the data indicate that adult learners need to be supported with materials to assist with building their capacity to know and apply understandings of fractions in a range of contexts, besides construction. Without materials and where fractions are taught via pen and paper tasks, students are less likely to retain and apply fraction ideas to their Certificate Course. Further they are less likely to understand decimals because of limited understanding of fractions.

Numerical estimation of 3D mechanical forces exerted by cells on non-linear materials

The exchange of physical forces in both cell-cell and cell-matrix interactions play a significant role in a variety of physiological and pathological processes, such as cell migration, cancer metastasis, inflammation and wound healing. Therefore, great interest exists in accurately quantifying the forces that cells exert on their substrate during migration. Traction Force Microscopy (TFM) is the most widely used method for measuring cell traction forces. Several mathematical techniques have been developed to estimate forces from TFM experiments. However, certain simplifications are commonly assumed, such as linear elasticity of the materials and/or free geometries, which in some cases may lead to inaccurate results. Here, cellular forces are numerically estimated by solving a minimization problem that combines multiple non-linear FEM solutions. Our simulations, free from constraints on the geometrical and the mechanical conditions, show that forces are predicted with higher accuracy than when using the standard approaches.

Dry tropics water smart : a community based approach to residential outdoor water consumption

This paper discusses the Townsville City Council Dry Tropics Water Smart (DTWS) initiative, developed by TCC Integrated Sustainability Services (ISS) and Townsville Water, and informed by The University of Adelaide. The program draws on many years of experience by the TCC team to blend key community-based research approaches in order to develop this residential outdoor water conservation program. Several community pilots have been conducted to test different behaviour change strategies and messages. This paper outlines recent steps taken to develop the community trials, as guided by a combination of behaviour change theories including community-based social marketing and thematic communications methods. Some preliminary results are outlined focused on community uptake of different strategies, community perceptions of communication materials, and some insights into the effectiveness of outdoor water hardware.

Groundwater table response to sea level rise and its impact on pavement structure

It has been predicted that sea level will rise about 0.8 m by 2100. Consequently, seawater can intrude into the coastal aquifers and change the level of groundwater table. A raise in groundwater table due to seawater intrusion threats the coastal infrastructure such as road pavements. The mechanical properties of subgrade materials will change due to elevated rise of groundwater table, leading to pavement weakening and decreasing the subgrade strength and stiffness. This paper presents an assessment of the vulnerability of subgrade in coastal areas to change in groundwater table due to sea-level rise. A simple bathtub approach is applied for estimating the groundwater level changes according to sea-level rise. Then the effect of groundwater level changes on the soil water content (SWC) of a single column of fine-sand soil is simulated using MIKE SHE. The impact of an increase in moisture content on subgrade strength/stiffness is assessed for a number of scenarios.

Bisphenol A degradation enhanced by air bubbles via advanced oxidation using in situ generated ferrous ions from nano zero-valent iron/palygorskite composite materials

Novel nano zero-valent iron/palygorskite composite materials prepared by evaporative and centrifuge methods are tested for the degradation of bisphenol A in an aqueous medium. A systematic study is presented which showed that nano zero-valent iron material has little effect on bisphenol A degradation. When hydrogen peroxide was added to initiate the reaction, some percentage of bisphenol A removal (∼20%) was achieved; however, with the aid of air bubbles, the percentage removal can be significantly increased to ∼99%. Compared with pristine nano zero-valent iron and commercial iron powder, nano zero-valent iron/palygorskite composite materials have much higher reactivity towards bisphenol A and these materials are superior as they have little impact on the solution pH. However, for pristine nano zero-valent iron, it is difficult to maintain the reaction system at a favourable low pH which is a key factor in maintaining high bisphenol A removal. All materials were characterized by X-ray diffraction, scanning electron microscopy, elemental analysis, transmission electron microscopy and X-ray photoelectron spectroscopy. The optimum conditions were obtained based on a series of batch experiments. This study has extended the application of nano zero-valent iron/palygorskite composites as effective materials for the removal of phenolic compounds from the environment.

Life cycle analysis for sustainability assessment of road projects

Road infrastructure has been considered as one of the most expensive and extensive infrastructure assets of the built environment globally. This asset also impacts the natural environment significantly during different phases of life e.g. construction, use, maintenance and end-of-life. The growing emphasis for sustainable development to meet the needs of future generations requires mitigation of the environmental impacts of road infrastructure during all phases of life e.g. construction, operation and end-of-life disposal (as required). Life-cycle analysis (LCA), a method of quantification of all stages of life, has recently been studied to explore all the environmental components of road projects due to limitations of generic environmental assessments. The LCA ensures collection and assessment of the inputs and outputs relating to any potential environmental factor of any system throughout its life. However, absence of a defined system boundary covering all potential environmental components restricts the findings of the current LCA studies. A review of the relevant published LCA studies has identified that environmental components such as rolling resistance of pavement, effect of solar radiation on pavement(albedo), traffic congestion during construction, and roadway lighting & signals are not considered by most of the studies. These components have potentially higher weightings for environment damage than several commonly considered components such as materials, transportation and equipment. This paper presents the findings of literature review, and suggests a system boundary model for LCA study of road infrastructure projects covering potential environmental components.