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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.
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In this paper, a technique to model strong and weak discontinuities with the scaled boundary finite element method through enrichment is proposed. The main advantage of the method is that the enriched elements, in the spirit of the extended finite element method (XFEM), do not need to physically conform to the geometry of features, e.g. internal interfaces and cracks, and remeshing is unnecessary as the interfaces evolve. All the advantages of the SBFEM and the XFEM are retained. The stress singularity at the crack tip can be captured accurately and the stress intensity factors (SIFs) can be directly computed based on the singular displacement or stress at the crack tip within the framework of the SBFEM. The numerical properties and performance for the proposed method are assessed using several numerical examples. In particular, problems with discontinuities, e.g. voids, inclusions, and cracks are analysed. The results show that the accuracy and convergence rate of the new approach for solving void or inclusion problems are identical to those of the XFEM, but requires less number of degrees-of-freedom than the XFEM. For crack problems, compared with the XFEM with topological enrichment, the developed method is superior.
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Objectives: Two experimental studies were conducted to test and compare whether different pre-performance routines (i.e., left-hand dynamic handgrip and an extensive routine) can improve (and potentially have a combined effect on) accuracy in closed, self-paced motor tasks. Design/method: Study 1 used a standardised laboratory task to measure motor performance, while Study 2 was a field experiment measuring tenpin bowling accuracy and in-game performance as outcome variables. Both studies consisted of a pretest phase followed by one or two test phases using a group-specific pre-performance routine (PPR), or control, condition. Results: Results of both studies indicated that the inexperienced students (Study 1) and experienced athletes (Study 2) within the intervention groups were more accurate when using the intervention than a control group (not provided an intervention). Using a combined (i.e., left-hand dynamic handgrip and extensive) PPR may not have additive performance effects. Furthermore, using a PPR intervention did not equate to better in-game performance in Study 2. Conclusions: These studies indicate that the element of left-hand dynamic handgrip as a PPR may be comparable to control groups, but further research is needed to determine if it is comparable to extensive PPR interventions that promote concentration on the task for increased performance generally (and under pressure).
Description:
Objectives: Two experimental studies were conducted to test and compare whether different pre-performance routines (i.e., left-hand dynamic handgrip and an extensive routine) can improve (and potentially have a combined effect on) accuracy in closed, self-paced motor tasks. Design/method: Study 1 used a standardised laboratory task to measure motor performance, while Study 2 was a field experiment measuring tenpin bowling accuracy and in-game performance as outcome variables. Both studies consisted of a pretest phase followed by one or two test phases using a group-specific pre-performance routine (PPR), or control, condition. Results: Results of both studies indicated that the inexperienced students (Study 1) and experienced athletes (Study 2) within the intervention groups were more accurate when using the intervention than a control group (not provided an intervention). Using a combined (i.e., left-hand dynamic handgrip and extensive) PPR may not have additive performance effects. Furthermore, using a PPR intervention did not equate to better in-game performance in Study 2. Conclusions: These studies indicate that the element of left-hand dynamic handgrip as a PPR may be comparable to control groups, but further research is needed to determine if it is comparable to extensive PPR interventions that promote concentration on the task for increased performance generally (and under pressure).
Description:
Background: Increased blood pressure is the biggest contributor to the global burden of disease and mortality. Data suggest that less than half of the population with hypertension is aware of it. May Measurement Month was initiated to raise awareness of the importance of blood pressure and as a pragmatic interim solution to the shortfall in screening programmes. Methods: This cross-sectional survey included volunteer adults (≥18 years) who ideally had not had their blood pressures measured in the past year. Each participant had their blood pressure measured three times and received a a questionnaire about demographic, lifestyle, and environmental factors. The primary objective was to raise awareness of blood pressure, measured by number of countries involved, number of people screened, and number of people who have untreated or inadequately treated hypertension (defined as systolic blood pressure ≥140 mm Hg or diastolic blood pressure ≥90 mm Hg, or both, or on the basis of receiving antihypertensive medication). Multiple imputation was used to estimate the mean of the second and third blood pressure readings if these were not recorded. Measures of association were analysed using linear mixed models. Findings: Data were collected from 1 201 570 individuals in 80 countries. After imputation, of the 1 128 635 individuals for whom a mean of the second and third readings was available, 393 924 (34·9%) individuals had hypertension. 153 905 (17·3%) of 888 616 individuals who were not receiving antihypertensive treatment were hypertensive, and 105 456 (46·3%) of the 227 721 individuals receiving treatment did not have controlled blood pressure. Significant differences in adjusted blood pressures and hypertension prevalence were apparent between regions. Adjusted blood pressure was higher in association with antihypertensive medication, diabetes, cerebrovascular disease, smoking, and alcohol consumption. Blood pressure was higher when measured on the right arm than on the left arm, and blood pressure was highest on Saturdays. Interpretation: Inexpensive global screening of blood pressure is achievable using volunteers and convenience sampling. Pending the set-up of systematic surveillance systems worldwide, MMM will be repeated annually to raise awareness of blood pressure. Funding: International Society of Hypertension, Centers for Disease Control and Prevention, Servier Pharmaceutical Co.
Description:
Background: Increased blood pressure is the biggest contributor to the global burden of disease and mortality. Data suggest that less than half of the population with hypertension is aware of it. May Measurement Month was initiated to raise awareness of the importance of blood pressure and as a pragmatic interim solution to the shortfall in screening programmes. Methods: This cross-sectional survey included volunteer adults (≥18 years) who ideally had not had their blood pressures measured in the past year. Each participant had their blood pressure measured three times and received a a questionnaire about demographic, lifestyle, and environmental factors. The primary objective was to raise awareness of blood pressure, measured by number of countries involved, number of people screened, and number of people who have untreated or inadequately treated hypertension (defined as systolic blood pressure ≥140 mm Hg or diastolic blood pressure ≥90 mm Hg, or both, or on the basis of receiving antihypertensive medication). Multiple imputation was used to estimate the mean of the second and third blood pressure readings if these were not recorded. Measures of association were analysed using linear mixed models. Findings: Data were collected from 1 201 570 individuals in 80 countries. After imputation, of the 1 128 635 individuals for whom a mean of the second and third readings was available, 393 924 (34·9%) individuals had hypertension. 153 905 (17·3%) of 888 616 individuals who were not receiving antihypertensive treatment were hypertensive, and 105 456 (46·3%) of the 227 721 individuals receiving treatment did not have controlled blood pressure. Significant differences in adjusted blood pressures and hypertension prevalence were apparent between regions. Adjusted blood pressure was higher in association with antihypertensive medication, diabetes, cerebrovascular disease, smoking, and alcohol consumption. Blood pressure was higher when measured on the right arm than on the left arm, and blood pressure was highest on Saturdays. Interpretation: Inexpensive global screening of blood pressure is achievable using volunteers and convenience sampling. Pending the set-up of systematic surveillance systems worldwide, MMM will be repeated annually to raise awareness of blood pressure. Funding: International Society of Hypertension, Centers for Disease Control and Prevention, Servier Pharmaceutical Co.
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Objectives: Youth rugby union is a popular sport with a high injury incidence density (IID) and burden. This high risk has called for further research into the factors affecting the injuries in youth rugby. The aim of the study was to analyse time-loss IID and burden in multiple schoolboy rugby teams over a season and the potential factors associated with injury. Design: Prospective cohort Methods: All time-loss injuries were recorded from three schools for the whole season. Overall IID and injury burden were calculated, as well as for injury event, type, location and the match quarter in which they occurred and Poisson regression analyses were performed to determine differences. Results: IID was 28.8 (18.9–38.6) injuries per 1000 player hours over the season, with an injury burden of 379.2 (343.6–414.9) days lost per 1000 player hours. The ball-carrier had a significantly higher IID (11.3 (5.2–17.5) per 1000 player hours) compared to other events, and the joint (non-bone)/ligament injuries were the most common (IID of 12.2 (5.8–18.6) per 1000 player hours) and severe type of injury (burden of 172.6 (148.5–196.6) days lost per 1000 player hours). Conclusions: The IID was similar to previous youth rugby studies, however the injury burden was much lower. The South African youth cohort showed similar factors associated with injury for inciting event (the tackle) and injury type (joint (non-bone)/ligament) and location (lower limb) as seen in other studies in both youth and senior players.
Description:
Objectives: Youth rugby union is a popular sport with a high injury incidence density (IID) and burden. This high risk has called for further research into the factors affecting the injuries in youth rugby. The aim of the study was to analyse time-loss IID and burden in multiple schoolboy rugby teams over a season and the potential factors associated with injury. Design: Prospective cohort Methods: All time-loss injuries were recorded from three schools for the whole season. Overall IID and injury burden were calculated, as well as for injury event, type, location and the match quarter in which they occurred and Poisson regression analyses were performed to determine differences. Results: IID was 28.8 (18.9–38.6) injuries per 1000 player hours over the season, with an injury burden of 379.2 (343.6–414.9) days lost per 1000 player hours. The ball-carrier had a significantly higher IID (11.3 (5.2–17.5) per 1000 player hours) compared to other events, and the joint (non-bone)/ligament injuries were the most common (IID of 12.2 (5.8–18.6) per 1000 player hours) and severe type of injury (burden of 172.6 (148.5–196.6) days lost per 1000 player hours). Conclusions: The IID was similar to previous youth rugby studies, however the injury burden was much lower. The South African youth cohort showed similar factors associated with injury for inciting event (the tackle) and injury type (joint (non-bone)/ligament) and location (lower limb) as seen in other studies in both youth and senior players.
Description:
Groundwater microorganisms hardly ever cover the solid matrix uniformly–instead they form micro-scale colonies. To which extent such colony formation limits the bioavailability and biodegradation of a substrate is poorly understood. We used a high-resolution numerical model of a single pore channel inhabited by bacterial colonies to simulate the transport and biodegradation of organic substrates. These high-resolution 2D simulation results were compared to 1D simulations that were based on effective rate laws for bioavailability-limited biodegradation. We (i) quantified the observed bioavailability limitations and (ii) evaluated the applicability of previously established effective rate concepts if microorganisms are heterogeneously distributed. Effective bioavailability reductions of up to more than one order of magnitude were observed, showing that the micro-scale aggregation of bacterial cells into colonies can severely restrict the bioavailability of a substrate and reduce in situ degradation rates. Effective rate laws proved applicable for upscaling when using the introduced effective colony sizes.
Description:
Groundwater microorganisms hardly ever cover the solid matrix uniformly–instead they form micro-scale colonies. To which extent such colony formation limits the bioavailability and biodegradation of a substrate is poorly understood. We used a high-resolution numerical model of a single pore channel inhabited by bacterial colonies to simulate the transport and biodegradation of organic substrates. These high-resolution 2D simulation results were compared to 1D simulations that were based on effective rate laws for bioavailability-limited biodegradation. We (i) quantified the observed bioavailability limitations and (ii) evaluated the applicability of previously established effective rate concepts if microorganisms are heterogeneously distributed. Effective bioavailability reductions of up to more than one order of magnitude were observed, showing that the micro-scale aggregation of bacterial cells into colonies can severely restrict the bioavailability of a substrate and reduce in situ degradation rates. Effective rate laws proved applicable for upscaling when using the introduced effective colony sizes.
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In this study, a novel biorefinery concept producing carbon fibre-poly(butylene succinate) composite foam (CPC foam) from lignocellulose and CO 2 is modelled. The biodegradable nature of poly(butylene succinate) would allow for easy carbon fibre recovery from the CPC foam for reuse at the end of product lifecycle, thus allowing for a circular materials flow. Technical simulation results show the biorefinery consumes 417 kg of biomass, 33 kg of CO 2 , 86 kg of methanol, 23 kg of acetic anhydride, 130 kWh of electricity and 1166 kW of heat per hour. The facility generates 72 kg of CPC foam, 82 kg of carbon fibre, 24 kg of tetrahydrofuran and 50 kg of dimethyl ether (DME). DME is used to fulfil parasitic electricity requirement. These results demonstrate the technical viability of this biorefinery although, research is needed to reduce parasitic energy demand. This carbon negative biorefinery avoids carcinogens and halogens for polymeric materials synthesis by utilising green chemistry principles and lignocellulose feedstock.
Description:
In this study, a novel biorefinery concept producing carbon fibre-poly(butylene succinate) composite foam (CPC foam) from lignocellulose and CO 2 is modelled. The biodegradable nature of poly(butylene succinate) would allow for easy carbon fibre recovery from the CPC foam for reuse at the end of product lifecycle, thus allowing for a circular materials flow. Technical simulation results show the biorefinery consumes 417 kg of biomass, 33 kg of CO 2 , 86 kg of methanol, 23 kg of acetic anhydride, 130 kWh of electricity and 1166 kW of heat per hour. The facility generates 72 kg of CPC foam, 82 kg of carbon fibre, 24 kg of tetrahydrofuran and 50 kg of dimethyl ether (DME). DME is used to fulfil parasitic electricity requirement. These results demonstrate the technical viability of this biorefinery although, research is needed to reduce parasitic energy demand. This carbon negative biorefinery avoids carcinogens and halogens for polymeric materials synthesis by utilising green chemistry principles and lignocellulose feedstock.
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The production of platform chemicals via carbon negative technologies will play an important role in global efforts to mitigate climate change. Succinic acid biorefineries are commercially mature carbon negative technologies that are plagued with large waste streams in the form of hemicellulose and gypsum. Here, a techno-economic analysis assesses the viability of a succinic acid biorefinery wherein hemicellulose is converted to acetic acid and dimethyl ether, and gypsum generation is avoided. Succinic acid is a feedstock for biodegradable plastics, acetic acid replaces petroleum-derived sources, and dimethyl ether is ideally suited as an energy storage vector. Our novel biorefinery concept presents an innovative integration of commercial technologies including water-splitting bipolar membrane electrodialysis for acid purification. The modelled multiproduct biorefinery (Multi Case)annually consumes 650,000 metric tonnes (t)of pulp logs, 135,000t of methanol, 1,700,000t of water, 42,000t of CO2 and 89 MW of electricity to produce 220,000t of succinic acid, 115,000t of acetic acid and 900t of dimethyl ether. All the parasitic electricity and heat duties are fulfilled within the biorefinery. Results show a CAPEX of AUD $635,000,000, OPEX of $180,000,000 and a succinic acid Minimum Selling Price of $990/t. Sensitivity and uncertainty analyses of the Multi Case biorefinery model show it is also resilient to price fluctuations.
Description:
The production of platform chemicals via carbon negative technologies will play an important role in global efforts to mitigate climate change. Succinic acid biorefineries are commercially mature carbon negative technologies that are plagued with large waste streams in the form of hemicellulose and gypsum. Here, a techno-economic analysis assesses the viability of a succinic acid biorefinery wherein hemicellulose is converted to acetic acid and dimethyl ether, and gypsum generation is avoided. Succinic acid is a feedstock for biodegradable plastics, acetic acid replaces petroleum-derived sources, and dimethyl ether is ideally suited as an energy storage vector. Our novel biorefinery concept presents an innovative integration of commercial technologies including water-splitting bipolar membrane electrodialysis for acid purification. The modelled multiproduct biorefinery (Multi Case)annually consumes 650,000 metric tonnes (t)of pulp logs, 135,000t of methanol, 1,700,000t of water, 42,000t of CO2 and 89 MW of electricity to produce 220,000t of succinic acid, 115,000t of acetic acid and 900t of dimethyl ether. All the parasitic electricity and heat duties are fulfilled within the biorefinery. Results show a CAPEX of AUD $635,000,000, OPEX of $180,000,000 and a succinic acid Minimum Selling Price of $990/t. Sensitivity and uncertainty analyses of the Multi Case biorefinery model show it is also resilient to price fluctuations.
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Optical and radiative properties of alumina–silica based ceramic materials are determined in the spectral range of 0.2–2.5 µm. The effects of material thermal treatment on the material structure, composition as well as optical and radiative properties are investigated using the commercial CARBO HSP materials and in-house fabricated samples with sintering temperatures of 1400