Epidemiology of injury and illness in 153 Australian international-level rowers over eight international seasons
- Authors: Trease, Larissa , Wilkie, Kellie , Lovell, Greg , Drew, Michael , Hooper, Ivan
- Date: 2020
- Type: Text , Journal article
- Relation: British Journal of Sports Medicine Vol. 54, no. 21 (2020), p. 1288-1293
- Full Text: false
- Reviewed:
- Description: Aim To report the epidemiology of injury and illness in elite rowers over eight seasons (two Olympiads). Methods All athletes selected to the Australian Rowing Team between 2009 and 2016 were monitored prospectively under surveillance for injury and illness. The incidence and burden of injury and illness were calculated per 1000 athlete days (ADs). The body area, mechanism and type of all injuries were recorded and followed until the resumption of full training. We used interrupted time series analyses to examine the association between fixed and dynamic ergometer testing on rowers' injury rates. Time lost from illness was also recorded. Results All 153 rowers selected over eight seasons were observed for 48 611 AD. 270 injuries occurred with an incidence of 4.1-6.4 injuries per 1000 AD. Training days lost totalled 4522 (9.2% AD). The most frequent area injured was the lumbar region (84 cases, 1.7% AD) but the greatest burden was from chest wall injuries (64 cases, 2.6% AD.) Overuse injuries (n=224, 83%) were more frequent than acute injuries (n=42, 15%). The most common activity at the time of injury was on-water rowing training (n=191, 68). Female rowers were at 1.4 times the relative risk of chest wall injuries than male rowers; they had half the relative risk of lumbar injuries of male rowers. The implementation of a dynamic ergometers testing policy (Concept II on sliders) was positively associated with a lower incidence and burden of low back injury compared with fixed ergometers (Concept II). Illness accounted for the greatest number of case presentations (128, 32.2% cases, 1.2% AD). Conclusions Chest wall and lumbar injuries caused training time loss. Policy decisions regarding ergometer testing modality were associated with lumbar injury rates. As in many sports, illness burden has been under-recognised in elite Australian rowers. ©
Extension of the scaled boundary finite element method to treat implicitly defined interfaces without enrichment
- Authors: Natarajan, Sundararajan , Dharmadhikari, Prasad , Annabattula, Ratna , Zhang, Junqi , Ooi, Ean , Song, Chongmin
- Date: 2020
- Type: Text , Journal article
- Relation: Computers and Structures Vol. 229, no. (2020), p.
- Full Text: false
- Reviewed:
- Description: In this paper, the scaled boundary finite element method (SBFEM) is extended to solve the second order elliptic equation with discontinuous coefficients and to treat weak discontinuities. The salient feature of the proposed technique is that: (a) it requires only the boundary to be discretized and (b) does not require the interface to be discretized. The internal boundaries are represented implicitly by the level set method and the zero level sets are used to identify the different regions. In the regions containing the interface, edges along the boundary are assigned different material properties based on their location with respect to the zero level set. A detailed discussion is provided on the implementation aspects, followed by a few example problems in both two and three dimensions to show the robustness, accuracy and effectiveness of the proposed approach in modelling materials with interfaces. The proposed technique can easily be integrated to any existing finite element code. © 2019 Elsevier Ltd
In vitro and in vivo toxicity and biodistribution of paclitaxel-loaded cubosomes as a drug delivery nanocarrier : a case study using an A431 skin cancer xenograft model
- Authors: Zhai, Jiali , Tan, Fiona , Luwor, Rodney , Srinivasa Reddy, T. , Ahmed, Nuzhat , Drummond, Calum , Tran, Nhiem
- Date: 2020
- Type: Text , Journal article
- Relation: ACS Applied Bio Materials Vol. 3, no. 7 (2020), p. 4198-4207
- Full Text: false
- Reviewed:
- Description: Cubosomes with an internal three-dimensional (3D) periodic and porous particulate nanostructure have emerged as a promising drug delivery system for hydrophobic small molecules as well as large biomolecules over the past several decades. Limited understanding of their safety profiles and biodistribution, however, hinders clinical translation. This study used monoolein-based cubosomes stabilized by Pluronic F127 and 1,2-distearoyl-sn-glycero-3-phosphoethanolamine-N-[maleimide(polyethylene glycol)] polymers to encapsulate paclitaxel (PTX) as a model drug and investigated the in vitro cytotoxicity, in vivo acute response, and whole body biodistribution of the developed nanoparticles. Comparison of the PTX and nanoparticle cytotoxicity in two-dimensional and 3D spheroid cell models revealed distinct differences, with the cells in the 3D model found to be more tolerable to unloaded PTX as well as the PTX-loaded nanoparticle form. One-time intraperitoneal (i.p.) injection of unloaded cubosomes were generally well tolerated up to 400 mg/kg. Using the A431 skin cancer xenograft model, in vivo imaging studies showed the preferential accumulation of PTX-loaded cubosomes at the tumor sites following i.p. injection. Lastly, average tumor size was reduced by approximately 50% in the nanoparticle-based treatment group compared to the unloaded PTX drug group. The study provides significant information on the biological response of cubosomes and highlights their potential as a versatile drug delivery platform for safe and effective delivery of chemotherapeutic drugs. © 2020 American Chemical Society.
- Description: The authors acknowledge the Capability Development Fund Scheme of RMIT University, the Maxwell Eagle Endowment Award and the CASS Foundation Science/Medicine Grant for financial support. N.T. is a recipient of an RMIT Vice-Chancellor’s Research Fellowship.
IR monitoring of absorbent composition and degradation during pilot plant operation
- Authors: Puxty, Graeme , Bennett, Robert , Conway, Will , Webster-Gardiner, Mike , Yang, Qi , Pearson, Pauline , Cottrell, Aaron , Huang, Sanger , Feron, Paul , Reynolds, Alicia , Verheyen, Vincent
- Date: 2020
- Type: Text , Journal article
- Relation: Industrial and Engineering Chemistry Research Vol. 59, no. 15 (2020), p. 7080-7086
- Full Text: false
- Reviewed:
- Description: The monitoring of the absorbent during the operation of CO2 separation processes is a necessary and challenging task. The most common absorbent used is an aqueous amine solution. Traditional approaches to analysis such as titration and chromatography are time-consuming and only provide limited information. This hinders the ability of process operators to rapidly respond to changes in operating conditions. In this work, a combination of infrared (IR) spectroscopy and principle component regression (PCR) analyses have been demonstrated as a rapid and reliable technique to determine the composition of an absorbent during a pilot plant campaign at a brown coal power station. The concentration of amine, a degradation product, CO2, and water was monitored throughout the campaign by a method that provided results in minutes. The results were verified by independent sample analysis using acid-base titration, high-performance liquid chromatography (HPLC), and 13C NMR spectroscopy. It was necessary to use spectral windowing when building the IR-PCR model, but this resulted in a robust and reliable method that has been demonstrated to work in a real-world process environment. © 2019 American Chemical Society.
- Description: The authors wish to acknowledge the financial assistance provided by the Brown Coal Innovation Australia, Ltd., a private member-based company with funding contracts through the Australian National Low Emissions Coal Research and Development, Ltd. (ANLEC R&D) and the Victorian State Government. The work described here was made possible through the PICA project, a collaboration between AGL Loy Yang, IHI, and CSIRO that aims to advance post-combustion CO 2 -capture technology in Australia.
Micro-scale heat transfer modelling of the contact line region of a boiling-sodium bubble
- Authors: Iyer, Siddharth , Kumar, Apurv , Coventry, Joe , Pye, John , Lipiński, Wojciech
- Date: 2020
- Type: Text , Journal article
- Relation: International Journal of Heat and Mass Transfer Vol. 160, no. (2020), p.
- Full Text: false
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- Description: The use of boiling liquid metals such as sodium is attractive for providing a near-isothermal heat source for engineering applications. However, previous use of boiling sodium as a coolant in nuclear reactors and as a heat transfer fluid in solar thermal applications has shown that the boiling process is unstable. To stabilise the flow, it is imperative to gain a better understanding of the boiling phenomena. An integral part of the boiling process is the evaporation of the region where the liquid-vapour interface meets the heater wall, referred to as the contact line region. The heat transfer modelling of this region formed below a single bubble in nucleate pool boiling of sodium is considered in this study. A contact line model previously developed for high Prandtl number flows is extended by including the effect of an electron pressure component which is unique to liquid metals. The assumptions made in the model are critically assessed to determine their validity for modelling micro-scale evaporation in sodium. The model was used to show that the evaporative heat flux from the contact line region in sodium can be up to six times larger compared to a high Prandtl number fluid FC-72 for a superheat of 15 K, owing to the high thermal conductivity of sodium. Furthermore, a study on the influence of specific characteristics of sodium — high boiling superheat and presence of an electron pressure — showed that the evaporative heat flux increases with increasing superheat and decreases with increasing electron pressure. © 2020 Elsevier Ltd
- Description: We gratefully acknowledge the financial support from the Australian Research Council (grant no. LP150101189 ). We thank our project partner Vast Solar Pty Ltd for their support and contributions.
Numerical modelling of radiation absorption in a novel multi-stage free-falling particle receiver
- Authors: Kumar, Apurv , Lipinski, Wojciech , Kim, Jin-Soo
- Date: 2020
- Type: Text , Journal article
- Relation: International Journal of Heat and Mass Transfer Vol. 146, no. (Jan 2020), p. 11
- Full Text: false
- Reviewed:
- Description: A novel multi-stage free-falling particle receiver design is proposed to improve the simple free-falling concept by enhancing the hydrodynamic stability and improving the radiation absorption of the particle curtain. The multi-stage design arising from repeated re-initialisation of the particle curtain by using intermediate troughs in the receiver results in an increased average volume fraction and residence time of the particles. The present work numerically solves the mass, momentum and radiative transfer equation for an isothermal two dimensional Eulerian-Eulerian particle-gas multiphase flow equations to estimate the absorption characteristics of the particle curtain. The multi-stage receiver concept significantly improves the absorptance of the curtain and reduces the reflection losses by over 50%. The reflection losses are seen to be insensitive to increase in size of the receiver making the multi-stage concept highly scalable. (C) 2019 Elsevier Ltd. All rights reserved.
Prediction of gold-bearing localised occurrences from limited exploration data
- Authors: Grigoryev, Igor , Bagirov, Adil , Tuck, Michael
- Date: 2020
- Type: Text , Journal article
- Relation: International Journal of Computational Science and Engineering Vol. 21, no. 4 (2020), p. 503-512
- Full Text: false
- Reviewed:
- Description: Inaccurate drill-core assay interpretation in the exploration stage presents challenges to long-term profit of gold mining operations. Predicting the gold distribution within a deposit as precisely as possible is one of the most important aspects of the methodologies employed to avoid problems associated with financial expectations. The prediction of the variability of gold using a very limited number of drill-core samples is a very challenging problem. This is often intractable using traditional statistical tools where with less than complete spatial information certain assumptions are made about gold distribution and mineralisation. The decision-support predictive modelling methodology based on the unsupervised machine learning technique, presented in this paper avoids some of the restrictive limitations of traditional methods. It identifies promising exploration targets missed during exploration and recovers hidden spatial and physical characteristics of the explored deposit using information directly from drill hole database. Copyright © 2020 Inderscience Enterprises Ltd.
Rainforest, woodland or swampland? Integrating time, space and culture to manage an endangered ecosystem complex in the Australian wet tropics
- Authors: Lynch, A. , Ferrier, Asa , Ford, A. J. , Haberle, Simon , Rule, Stephen , Schneider, Larissa , Zawadzki, A. , Metcalfe, Daniel
- Date: 2020
- Type: Text , Journal article
- Relation: Landscape Ecology Vol. 35, no. 1 (2020), p. 83-99
- Full Text: false
- Reviewed:
- Description: Context: Transdisciplinary research is important where information from multiple fields is required to develop ecologically and culturally appropriate environmental planning that protects local conservation and socio-cultural values. Objectives: Here, we describe research to inform ecosystem restoration and conservation of Chumbrumba Swamp within the Wet Tropics World Heritage Area, Australia. Many such open wetlands in the region have been degraded through agriculture and pastoral production, but there has been little research into their status, history and conservation needs. Methods: The recent to pre-European settlement history of the site was explored, along with spatial variation of vegetation communities at the site, and these data integrated with historical and ethnographical information on the site and its cultural values. Results: The botanical and palaeoecological analyses showed that Chumbrumba Swamp comprises a unique and highly sensitive ecosystem mosaic with high biodiversity. An endangered ecosystem complex, 82 vascular plant species, several disjunct or endemic taxa, and species at new northern range limits were recorded within its 20 ha area. The site comprises a stable swamp site with fringing woodland and rainforest that has persisted for around 5000 years. European settlement overlaid changes in the vegetation from disturbance (e.g. fire, clearing, grazing). However, fire also affected the swamp site during pre-European times. Conclusions: Historical and ethnographic information contextualised the biophysical data and confirmed the cultural importance of the site and the dynamic interactions between ‘people and nature’. These results have been used to inform environmental restoration and validate the importance of a transdisciplinary and precautionary approach to planning wetland restoration and conservation. © 2019, Springer Nature B.V.
Rib stress injuries in the 2012-2016 (Rio) Olympiad : a cohort study of 151 Australian rowing team athletes for 88 773 athlete days
- Authors: Harris, Rachel , Trease, Larissa , Wilkie, Kellie , Drew, Michael
- Date: 2020
- Type: Text , Journal article
- Relation: British Journal of Sports Medicine Vol. 54, no. 16 (2020), p. 991-996
- Full Text: false
- Reviewed:
- Description: Aim To describe the demographics, frequency, location, imaging modality and clinician-identified factors of rib stress injury in a cohort of elite rowers over the Rio Olympiad (2012-2016). Methods Analysis of prospectively recorded medical records for the Australian Rowing Team in 2013-2015 and the combined Australian Rowing Team and Olympic Shadow Squad in 2016, examining all rib stress injuries. Results 19 rib stress injuries (12 reactions and 7 fractures) were identified among a cohort of 151 athletes and included 12 female and 7 male cases, 11 open weight, 8 lightweight, 12 scull and 7 sweep cases. The most common locations of injury identified by imaging, were the mid-axillary line and rib 6. Period prevalence varied from 4 to 15.4 and incidence ranged from 0.27 to 0.13 per 1000 athlete days. There were no significant differences in prevalence by sex, sweep versus scull or weight class. There was a statistically significant increase in incidence in the pre-Olympic year (2015, p<0.001). MRI was the most commonly used modality for diagnosis. Stress fracture resulted in median 69 (IQR 56-157) and bone stress reaction resulted in 57 (IQR 45-78) days lost to full on water training. Conclusions In our 4-year report of rib stress injury in elite rowing athletes, period prevalence was consistent with previous reports and time lost (median
River management and environmental water allocation in regulated ecosystems of arid and semi-arid regions – a review
- Authors: Atazadeh, Ehsan , Barton, Andrew , Shirinpour, Mozhgan , Zarghami, Mahdi , Rajabifard, Abbas
- Date: 2020
- Type: Text , Journal article
- Relation: Fundamental and Applied Limnology Vol. 193, no. 4 (2020), p. 327-345
- Full Text: false
- Reviewed:
- Description: Rivers make a significant contribution in providing goods and services for human well-being. Today, many rivers and streams have been heavily regulated to ensure adequate provision of water resources for anthropogenic uses. Riverine ecosystems, especially those in arid and semi-arid regions, are experiencing severe stress due to the increasing demands on the ecosystem services they provide, coupled with anthropogenic catchment-scale impacts and factors associated with natural and human-induced climate variability and change. In this paper, the various flow components in regulated riverine ecosystems and the methods to determine environmental flows are reviewed. The review also focuses on the concurrent developments of eco-hydrological models and on the new opportunities for improving environmental flows of rivers by sustainably adjusting consumptive flows to fine-tune environmental flows and maximize the ecological benefit. In fact, the present paper highlights the role of consumptive flows, towards improving environmental flows, which has largely been neglected by river scientists and water managers. Indeed, consumptive flows can provide an opportunity to improve and support environmental flows in regulated riverine ecosystems. Addressing these challenges may aid water management efforts in finding sustainable solutions in riverine ecosystems by balancing environmental/ecological and human water requirements. © 2020 E. Schweizerbart’sche Verlagsbuchhandlung, Stuttgart, Germany.
Thermal and thermal damage responses during switching bipolar radiofrequency ablation employing bipolar needles : a computational study on the effects of different electrode configuration, input voltage and ablation duration
- Authors: Cheong, Jason , Ooi, Ean Hin , Ooi, Ean Tat
- Date: 2020
- Type: Text , Journal article
- Relation: International Journal for Numerical Methods in Biomedical Engineering Vol. 36, no. 9 (2020), p.
- Full Text: false
- Reviewed:
- Description: Recent studies have demonstrated the effectiveness of switching bipolar radiofrequency ablation (bRFA) in treating liver cancer. Nevertheless, the clinical use of the treatment remains less common than conventional monopolar RFA – likely due to the lack of understanding of how the tissues respond thermally to the switching effect. The problem is exacerbated by the numerous possible switching combinations when bRFA is performed using bipolar needles, thus making theoretical deduction and experimental studies difficult. This article addresses this issue via computational modelling by examining if significant variation in the treatment outcome exists amongst six different electrode configurations defined by the X-, C-, U-, N-, Z- and O-models. Results indicated that the tissue thermal and thermal damage responses varied depending on the electrode configuration and the operating conditions (input voltage and ablation duration). For a spherical tumour, 30 mm in diameter, complete ablation could not be attained in all configurations with 70 V input voltage and 5 minutes ablation duration. Increasing the input voltage to 90 V enlarged the coagulation zone in the X-model only. With the other configurations, extending the ablation duration to 10 minutes was found to be the better at enlarging the coagulation zone. © 2020 John Wiley & Sons, Ltd.
Wifi-based localisation datasets for No-GPS open areas using smart bins
- Authors: Nassar, Mohamed , Hasan, Mahmud , Khan, Md , Sultana, Mirza , Hasan, Md , Luxford, Len , Cole, Peter , Oatley, Giles , Koutsakis, Polychronis
- Date: 2020
- Type: Text , Journal article , Data article
- Relation: Computer Networks Vol. 180, no. (2020), p. 1-5
- Full Text: false
- Reviewed:
- Description: In recent years, Wifi-based localisation systems have gained significant interest because of the lack of Global Positioning System (GPS) signal in indoor and certain open areas. Over the past decade, many datasets have been introduced to enable researchers to compare different localisation techniques. Existing datasets, however, have failed to cover open areas such as parks in cases where GPS is still unavailable, and there is a lack of Wifi access points. Also, the existing datasets only focus on getting Wifi fingerprint collected and labelled by users. To the best of our knowledge, no dataset provides Received Signal Strengths (RSS) collected by Wireless Access Points (APs). In this work, we offer two datasets publicly. The first is the Fingerprint dataset in which four users generated 16,032 accurate and consistently labelled WiFi fingerprints for all available Reference Points (RPs) in a central and busy area of Murdoch University, known as Bush Court. The second is the APs dataset that includes 2,450,865 auto-generated records received from 1000 users' devices, including the four users, associated with Wifi signal strengths. To overcome the Wifi coverage problem for the Bush Court, we attached our previously designed Wireless Sensor Nodes (WSNs) to existing garbage bins, enabling them to provide real-time environmental sensing and act as soft APs that sense MAC addresses and Wifi signals from surrounding devices.
Adaptive phase-field modeling of brittle fracture using the scaled boundary finite element method
- Authors: Hirshikesh , Pramod, Aladurthi , Annabattula, Ratna , Ooi, Ean Tat , Song, Chongmin , Natarajan, Sundararajan
- Date: 2019
- Type: Text , Journal article
- Relation: Computer Methods in Applied Mechanics and Engineering Vol. 355, no. (2019), p. 284-307
- Full Text: false
- Reviewed:
- Description: In this work, we propose an adaptive phase field method (PFM) to simulate quasi-static brittle fracture problems. The phase field equations are solved using the scaled boundary finite element method (SBFEM). The adaptive refinement strategy is based on an error indicator evaluated directly from the solutions of the SBFEM without any need for stress recovery techniques. Quadtree meshes are adapted to perform mesh refinement. The polygons with hanging nodes in the quadtree decomposition are treated as n−sided polygons within the framework of the SBFEM and do not require any special treatment in contrast to the conventional finite element method. Several benchmark problems are used to demonstrate the robustness and the efficacy of the proposed technique. The adaptive refinement strategy reduces the mesh burden when adopting the PFM to model fracture. Numerical results show an improvement in the computational efficiency in terms of the number of elements required in the standard PFM without compromising the accuracy of the solution.
Effects of introducing innovative teaching methods in engineering classes : A case study on classes in an Indian university
- Authors: Subramanian, Dhenesh , Kelly, Patricia
- Date: 2019
- Type: Text , Journal article
- Relation: Computer Applications in Engineering Education Vol. 27, no. 1 (2019), p. 183-193
- Full Text: false
- Reviewed:
- Description: Technology has been revolutionized in the past few decades and its impacts on student learning have not been fully explored. The digital divide between a student's personal technology usage and its use within the classroom remains to be bridged. This study focuses on using technology-based innovative teaching methods with engineering classes and understanding their impact on students. The findings suggest that these learners benefited from and prefer to use innovative teaching methods backed by technology support in class. Students deprived of such innovative methods and technology would prefer to have them introduced to aid their learning experience. The study strengthens the need for decision makers in educational institutions to invest in innovative teaching methods supported by technology in order to provide a better learning platform for students, particularly in India, where engineering graduates are regarded as lacking essential skills in communication and innovation.
Scaled boundary finite element method for compressible and nearly incompressible elasticity over arbitrary polytopes
- Authors: Aladurthi, Lakshmi , Natarajan, Sundararajan , Ooi, Ean Tat , Song, Chongmin
- Date: 2019
- Type: Text , Journal article
- Relation: International Journal for Numerical Methods in Engineering Vol. 119, no. 13 (2019), p. 1379-1394
- Full Text: false
- Reviewed:
- Description: In this paper, a purely displacement-based formulation is presented within the framework of the scaled boundary finite element method to model compressible and nearly incompressible materials. A selective reduced integration technique combined with an analytical treatment in the nearly incompressible limit is employed to alleviate volumetric locking. The stiffness matrix is computed by solving the scaled boundary finite element equation. The salient feature of the proposed technique is that it neither requires a stabilization parameter nor adds additional degrees of freedom to handle volumetric locking. The efficiency and the robustness of the proposed approach is demonstrated by solving various numerical examples in two and three dimensions.
The effects of electrical and thermal boundary condition on the simulation of radiofrequency ablation of liver cancer for tumours located near to the liver boundary
- Authors: Ooi, Ean Hin , Lee, Khiy , Yap, Shelley , Khattab, Mahmoud , Liao, Iman , Ooi, Ean Tat , Foo, Ji , Nair, Shalini , Ali, Ahmad
- Date: 2019
- Type: Text , Journal article
- Relation: Computers in Biology and Medicine Vol. 106, no. (2019), p. 12-23
- Full Text: false
- Reviewed:
- Description: Effects of different boundary conditions prescribed across the boundaries of radiofrequency ablation (RFA) models of liver cancer are investigated for the case where the tumour is at the liver boundary. Ground and Robin-type conditions (electrical field) and body temperature and thermal insulation (thermal field) conditions are examined. 3D models of the human liver based on publicly-available CT images of the liver are developed. An artificial tumour is placed inside the liver at the boundary. Simulations are carried out using the finite element method. The numerical results indicated that different electrical and thermal boundary conditions led to different predictions of the electrical potential, temperature and thermal coagulation distributions. Ground and body temperature conditions presented an unnatural physical conditions around the ablation site, which results in more intense Joule heating and excessive heat loss from the tissue. This led to thermal damage volumes that are smaller than the cases when the Robin type or the thermal insulation conditions are prescribed. The present study suggests that RFA simulations in the future must take into consideration the choice of the type of electrical and thermal boundary conditions to be prescribed in the case where the tumour is located near to the liver boundary.
The role of interoperable data standards in precision livestock farming in extensive livestock systems : A review
- Authors: Bahlo, Christiane , Dahlhaus, Peter , Thompson, Helen , Trotter, Mark
- Date: 2019
- Type: Text , Journal article , Review
- Relation: Computers and Electronics in Agriculture Vol. 156, no. (2019), p. 459-466
- Full Text: false
- Reviewed:
- Description: Livestock industries are increasingly embracing precision farming and decision support tools. As a result, sensors, weather stations, individual animal tracking, feed monitoring and other sources create large data volumes, much of which is used only for a single purpose. There are unrealised potential benefits of making on farm data interoperable and accessible and federating it with public data sources. We reviewed recent literature on precision livestock farming (PLF) technologies in relation to the use of public data, open standards and interoperability. Livestock farms produce rising volumes of disparate private datasets, reflecting a variety of information needs and technological opportunities, but typically lacking interoperable formats and metadata. These as well as large amounts of accessible public datasets are currently underutilised in decision support tools. Tools that demonstrate the use of interoperable standards and bring together public and private data for decision support can enhance the value proposition and help lower barriers to the sharing and re-use of data. This review of interoperable standards in extensive livestock farming systems concludes that there is a need for not only a new type of decision support tool, but also a consensus on data exchange standards to prove the value of shared data at farm scale (commercial benefit) and a regional scale (public good). © 2018
3D Finite element modeling of circular reinforced concrete columns confined with FRP using a plasticity based formulation
- Authors: Piscesa, Bambang , Attard, Mario , Samani, Ali Khajeh
- Date: 2018
- Type: Text , Journal article
- Relation: Composite Structures Vol. 194, no. (2018), p. 478-493
- Full Text: false
- Reviewed:
- Description: Strengthening reinforced concrete (RC) columns with external confining devices such as FRP wraps or steel tube is widely used in construction. By using external confining devices, both the strength and ductility of RC columns are significantly improved. However, numerical modeling to predict the capacity of strengthened RC columns is limited and often oversimplified. One of the biggest challenges in numerical modeling is to deal with unequal dilation between the concrete inner core (enclosed by both transverse steel and FRP wraps) and the concrete outer core (between the transverse steel and FRP wraps). Inaccurate modeling on the concrete dilatant behavior can lead to incorrect strength prediction. Sophisticated constitutive models which are able to model concrete dilation and robust modeling techniques are required. In this paper, three-dimensional non-linear finite element analysis (3D-NLFEA) of circular RC columns confined with conventional steel stirrups and FRP wraps is presented. In the FEA, the initial stiffness method with Process Modification (acceleration technique) is used to solve the equilibrium forces in the global solution. The constitutive model is based on the plasticity formulation proposed by the authors, which can capture the effective lateral modulus (EL) of the confining devices. This lateral modulus is obtained by observing the principal incremental stresses and strains at each element gauss point. It was found that, the lateral modulus is greatly affected by the boundary condition, dilatant behavior of the constitutive model and the Poisson's ratio of the external confining device. To validate the performance of the proposed model, several comparisons of the proposed model, using 3D-NLFEA, with experimental results is presented. The comparisons show that the predicted response using 3D-NLFEA and the experimental results of RC columns confined with FRP are in a good agreement.
A novel scaled boundary finite element formulation with stabilization and its application to image-based elastoplastic analysis
- Authors: He, Ke , Song, Chongmin , Ooi, Ean Tat
- Date: 2018
- Type: Text , Journal article
- Relation: International Journal for Numerical Methods in Engineering Vol. 115, no. 8 (2018), p. 956-985
- Full Text: false
- Reviewed:
- Description: Digital images are increasingly being used as input data for computational analyses. This study presents an efficient numerical technique to perform image-based elastoplastic analysis of materials and structures. The quadtree decomposition algorithm is employed for image-based mesh generation, which is fully automatic and highly efficient. The quadtree cells are modeled by scaled boundary polytope elements, which eliminate the issue of hanging nodes faced by standard finite elements. A novel, simple, and efficient scaled boundary elastoplastic formulation with stablisation is developed. In this formulation, the return-mapping calculation is only required to be performed at a single point in a polytope element, which facilitates the computational efficiency of the elastoplastic analysis and simplicity of implementation. Numerical examples are presented to demonstrate the efficiency and accuracy of the proposed technique for performing the elastoplastic analysis of high-resolution images.
A technology review for regeneration of sulfur rich amine systems
- Authors: Garg, Bharti , Verheyen, Vincent , Pearson, Pauline , Feron, Paul , Cousins, Ashleigh
- Date: 2018
- Type: Text , Journal article , Review
- Relation: International Journal of Greenhouse Gas Control Vol. 75, no. (2018), p. 243-253
- Full Text: false
- Reviewed:
- Description: Reducing the capital cost of post combustion CO2 capture by eliminating flue gas desulfurisation (FGD) pre-treatment, requires management of the amines preferential SO2 absorption. Novel technologies such as CS-Cap restrict the impact of SO2 to only a small fraction of the amine inventory resulting in high sulfate burden amines. Traditional thermal reclamation of these spent absorbents has advantages regarding simplicity, but ranks poorly for industrial ecology around PCC. These amines require low energy regeneration technologies compatible with their physico-chemical properties that also maximise the potential for valorising by-products. This review summarises the sulfur chemistry and outlines several amine reclamation processes. It assesses the status of established and novel regeneration technologies for their applicability to high sulfur loaded amines. Should deep sulfur removal be required, a hybrid approach with initial bulk removal (as product) followed by a polishing step to further reduce sulfur is prospective. A preliminary estimation of the relative cost of using standard reclamation methods for treating Sulfur loaded CS-Cap absorbent revealed the cost would increase due to its higher sulfate burden despite comparable treatment volumes. Research gaps are identified which would enable better comparison between the costs of traditional FGD versus higher reclamation costs for combined capture technologies.