Assessment of post-contingency congestion risk of wind power with asset dynamic ratings
- Authors: Banerjee, Binayak , Jayaweera, Dilan , Islam, Syed
- Date: 2015
- Type: Text , Journal article
- Relation: International Journal of Electrical Power and Energy Systems Vol. 69, no. (2015), p. 295-303
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- Description: Large scale integration of wind power can be deterred by congestion following an outage that results in constrained network capacity. Post outage congestion can be mitigated by the application of event control strategies; however they may not always benefit large wind farms. This paper investigates this problem in detail and proposes an advanced mathematical framework to model network congestion as functions of stochastic limits of network assets to capture post contingency risk of network congestion resulting through the constrained network capacity that limits high penetration of wind. The benefit of this approach is that it can limit the generation to be curtailed or re-dispatched by dynamically enhancing the network latent capacity in the event of outages or as per the need. The uniqueness of the proposed mathematical model is that it converts conventional thermal constraints to dynamic constraints by using a discretized stochastic penalty function with quadratic approximation of constraint relaxation penalty. The case study results with large and small network models suggest that the following an outage, wind utilization under dynamic line rating can be increased considerably if the wind power producers maintain around a 15% margin of operation.
Australian Honours degrees : The last bastion of quality?
- Authors: Backer, Elisa , Benckendorff, Pierre
- Date: 2018
- Type: Text , Journal article
- Relation: Journal of Hospitality and Tourism Management Vol. 36, no. (2018), p. 49-56
- Full Text: false
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- Description: The first tourism Honours degree in Australia was offered almost three decades ago, and since then Honours has become a well-recognised and important offering, particularly in terms of its role as a research pathway. The research-intensive nature of Honours degrees produces graduates who are able to plan and execute project work, undertake research, and demonstrate scholarship with some independence. These skills are highly sought after by some employers. However, Honours programs tend to be ‘boutique’ offerings and are particularly vulnerable to curriculum rationalisation efforts. The purpose of this research was to explore the value and future of Australian business Honours degrees by examining the perceptions of tourism and business educators. A survey of 100 academics from 21 Australian institutions revealed that Honours is highly valued and considered to be superior as a research training degree in comparison to Masters Coursework Degrees and Masters by Research. However, in an era of increasing austerity the Australian Honours degree has become an oddity and its reputation as the last bastion of quality in undergraduate tourism education is under threat. © 2018
Interventions preventing ankle sprains; previous injury and high-risk sport participation as predictors of compliance
- Authors: Janssen, Kasper , Van Der Zwaard, Babette , Finch, Caroline , van Mechelen, Willem , Verhagen, Evert
- Date: 2016
- Type: Text , Journal article
- Relation: Journal of Science and Medicine in Sport Vol. 19, no. 6 (Jun 2016), p. 465-469
- Full Text: false
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- Description: Objectives: To describe the association between participants' person-related potential predictor variables and cumulative compliance with interventions for preventing ankle sprains: neuromuscular training, wearing an ankle brace, and a combined training and bracing. Design: Secondary analysis of compliance data from a randomized controlled trial (RCT) comparing measures preventing ankle ligament injuries. Methods: Ordinal regression with a backward selection method was used to obtain a descriptive statistical model linking participants' person-related potential predictor variables with the monthly cumulative compliance measurements for three interventions preventing ankle ligament injuries. Results: Having had a previous ankle injury was significantly associated with a higher compliance with all of the preventive measures trialed. Overall compliance with bracing and the combined intervention was significantly lower than the compliance with NM training. Per group analysis found that participating in a high-risk sport, like soccer, basketball, and volleyball, was significantly associated with a higher compliance with bracing, or a combined bracing and NM training. In contrast, participating in a high-risk sport was significantly associated with a lower per group compliance with NM training. Conclusions: Future studies should include at least registration of previous ankle sprains, sport participation (high- or low-risk), experience in NM training, and hours of sport exposure as possible predictors of compliance with interventions preventing ankle sprains. Practitioners should take into account these variables when prescribing preventive neuromuscular training or bracing. (C) 2015 Sports Medicine Australia. Published by Elsevier Ltd. All rights reserved.
A continental narrative : Human settlement patterns and Australian climate change over the last 35,000 years
- Authors: Williams, Alan , Veth, Peter , Steffen, Will , Ulm, Sean , Turney, Chris , Reeves, Jessica , Phipps, Steven , Smith, Mike
- Date: 2015
- Type: Text , Journal article
- Relation: Quaternary Science Reviews Vol. 123, no. (2015), p. 91-112
- Full Text: false
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- Description: Drawing on the recent synthesis of Australian palaeoclimate by the OZ-INTIMATE group (Reeves etal., 2013a), we consider the effects of climate systems on past human settlement patterns and inferred demography. We use 5044 radiocarbon dates from ~1750 archaeological sites to develop regional time-series curves for different regions defined in the OZ-INTIMATE compilation as the temperate, tropics, interior and Southern Ocean sectors to explore human-climate relationships in Australia over the last 35,000 years. Correlations undertaken with improved palaeoclimatic data and archaeological records indicate that the regional time-series curves are robust, and can be used as a proxy for human behaviour. However, interrogation of the datasets is essential with artificial peaks and taphonomic over-correction being critical considerations. The time-series curves are interpreted as reflecting population growth, stasis and even decline in phase with terminal Pleistocene/early Holocene climatic fluctuations. This coupling, however, decreases during the last 5000 years, most likely due to increased population levels, greater territoriality, technological solutions to stress, and social and ideational innovation. Curves from all sectors show exponential population growth over the last 5000 years. We identify future research priorities, highlighting the paucity of archaeological records across several parts of Australia (<1 dated site/4,000km2), especially around the fringes of the arid zone, and the need for improved taphonomic correction techniques. Finally, we discuss how these time-series curves represent a first-order framework, not dissimilar to global climate models, which researchers can continue to test and refine with local, regional and continental records. © 2015.
Angiotensin converting enzyme 2 and atherosclerosis
- Authors: Wang, Yutang , Tikellis, Chris , Thomas, Merlin , Golledge, Jonathan
- Date: 2013
- Type: Text , Journal article , Review
- Relation: Atherosclerosis Vol. 226, no. 1 (2013), p. 3-8
- Full Text: false
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- Description: Angiotensin converting enzyme 2 (ACE2) is a homolog of angiotensin converting enzyme (ACE) which generates angiotensin II from angiotensin I. ACE, its product angiotensin II and the downstream angiotensin type I receptor are important components of the renin-angiotensin system (RAS). Angiotensin II, the most important component of the RAS, promotes the development of atherosclerosis. The identification of ACE2 in 2000 opened a new chapter of research on the regulation of the RAS. ACE2 degrades pro-atherosclerotic angiotensin II and generates anti-atherosclerotic angiotensin 1-7. In this review, we explored the importance of ACE2 in protecting experimental animals from developing atherosclerosis and its involvement in human atherosclerosis. We also examined the published evidence assessing the importance of ACE2 in different cell types relevant to atherosclerosis and putative underlying cellular and molecular mechanisms linking ACE2 with protection from atherosclerosis. ACE2 shifts the balance from angiotensin II to angiotensin 1-7 inhibiting the progression of atherosclerosis in animal models. © 2012 Elsevier Ireland Ltd.
Simplifying and improving ant-based clustering
- Authors: Tan, Swee , Ting, Kaiming , Teng, Shyh
- Date: 2011
- Type: Text , Conference paper
- Relation: 11th International Conference on Computational Science, ICCS 2011; Singapore, Singapore; 1st-3rd June 2011, published in Procedia Computer Science Vol. 4, p. 46-55
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- Description: Ant-based clustering (ABC) is a data clustering approach inspired from cemetery formation activities observed in real ant colonies. Building upon the premise of collective intelligence, such an approach uses multiple ant-like agents and a mixture of heuristics, in order to create systems that are capable of clustering real-world data. Many recently proposed ABC systems have shown competitive results, but these systems are geared towards adding new heuristics, resulting in increasingly complex systems that are harder to understand and improve. In contrast to this direction, we demonstrate that a state-of-the-art ABC system can be systematically evaluated and then simplified. The streamlined model, which we call SABC, differs fundamentally from traditional ABC systems as it does not use the ant-colony and several key components. Yet, our empirical study shows that SABC performs more effectively and effciently than the state-of-the-art ABC system.
Using video analysis for concussion surveillance in Australian football
- Authors: Makdissi, Michael , Davis, Gavin
- Date: 2016
- Type: Text , Journal article
- Relation: Journal of Science and Medicine in Sport Vol. 19, no. 12 (2016), p. 958-963
- Full Text: false
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- Description: Objectives: The objectives of the study were to assess the relationship between various player and game factors and risk of concussion; and to assess the reliability of video analysis for mechanistic assessment of concussion in Australian football. Methods: All impacts and collisions resulting in concussion were identified during the 2011 Australian Football League season. An extensive list of factors for assessment was created based upon previous analysis of concussion in Australian Football League and expert opinions. The authors independently reviewed the video clips and correlation for each factor was examined. Results: A total of 82 concussions were reported in 194 games (rate: 8.7 concussions per 1000 match hours; 95% confidence interval: 6.9-10.5). Player demographics and game variables such as venue, timing of the game (day, night or twilight), quarter, travel status (home or interstate) or score margin did not demonstrate a significant relationship with risk of concussion; although a higher percentage of concussions occurred in the first 5 min of game time of the quarter (36.6%), when compared to the last 5 min (20.7%). Variables with good inter-rater agreement included position on the ground, circumstances of the injury and cause of the impact. The remainder of the variables assessed had fair-poor inter-rater agreement. Common problems included insufficient or poor quality video and interpretation issues related to the definitions used. Conclusions: Clear definitions and good quality video from multiple camera angles are required to improve the utility of video analysis for concussion surveillance in Australian football. (C) 2016 Sports Medicine Australia. Published by Elsevier Ltd. All rights reserved.
Weaker conditions for subdifferential calculus of convex functions
- Authors: Correa, Rafael , Hantoute, Abderrahim , López, Marco
- Date: 2016
- Type: Text , Journal article
- Relation: Journal of Functional Analysis Vol. 271, no. 5 (2016), p. 1177-1212
- Relation: http://purl.org/au-research/grants/arc/DP160100854
- Full Text: false
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- Description: In this paper we establish new rules for the calculus of the subdifferential mapping of the sum of two convex functions. Our results are established under conditions which are at an intermediate level of generality among those leading to the Hiriart-Urruty and Phelps formula (Hiriart-Urruty and Phelps, 1993 [15]), involving the approximate subdifferential, and the stronger assumption used in the well-known Moreau-Rockafellar formula (Rockafellar 1970, [23]; Moreau 1966, [20]), which only uses the exact subdifferential. We give an application to derive asymptotic optimality conditions for convex optimization.
- Description: In this paper we establish new rules for the calculus of the subdifferential mapping of the sum of two convex functions. Our results are established under conditions which are at an intermediate level of generality among those leading to the Hiriart-Urruty and Phelps formula (Hiriart-Urruty and Phelps, 1993 [15]), involving the approximate subdifferential, and the stronger assumption used in the well-known Moreau-Rockafellar formula (Rockafellar 1970, [23]; Moreau 1966, [20]), which only uses the exact subdifferential. We give an application to derive asymptotic optimality conditions for convex optimization. (C) 2016 Elsevier Inc. All rights reserved.
Why articles continue to be cited after they have been retracted : An audit of retraction notices
- Authors: Gray, Richard , Al-Ghareeb, Amal , McKenna, Lisa
- Date: 2019
- Type: Text , Journal article
- Relation: International Journal of Nursing Studies Vol. 90, no. (2019), p. 11-12
- Full Text: false
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- Description: Background: Papers continue to be cited by authors even after they have been retracted. Retraction notices provide readers with information about retracted papers and may help minimise post-retraction citation. To date, a review of the quality of retraction notices in nursing science has not been reported. Design: An audit of retraction notices associated with 29 retracted manuscripts published in nursing science journals. Methods: Retraction notices were reviewed again using the Committee on Publication Ethics (COPE) guidelines. Results: In total, 28 retraction notices were retrieved and reviewed (one retracted paper did not have a retraction notice). Details of the retracted manuscripts were included in all reviewed notices and, in all but two, author names were reported. Details of the time between a paper being published and retracted were not reported and generally there was a little information in notices about how the retraction decisions were made. All retraction notices were freely available. Seven notices stated who had made the decision to retract. Twenty-two (77%) notices stated the reason for retraction. Notices were brief and contained factual information. The webpages of three retracted articles did not clearly indicate that the paper had been retracted. Conclusion: More detailed and informative retraction notices will inform readers and may help reduce post- retraction citation.
Use of video to facilitate sideline concussion diagnosis and management decision-making
- Authors: Davis, Gavin , Makdissi, Michael
- Date: 2016
- Type: Text , Journal article
- Relation: Journal of Science and Medicine in Sport Vol. 19, no. 11 (2016), p. 898-902
- Full Text: false
- Reviewed:
- Description: Objectives: Video analysis can provide critical information to improve diagnostic accuracy and speed of clinical decision-making in potential cases of concussion. The objective of this study was to validate a hierarchical flowchart for the assessment of video signs of concussion, and to determine whether its implementation could improve the process of game day video assessment. Methods: All impacts and collisions potentially resulting in a concussion were identified during 2012 and 2013 Australian Football League (AFL) seasons. Consensus definitions were developed for clinical signs associated with concussion. A hierarchical flowchart was developed based on the reliability and validity of the video signs of concussion. Ninety videos were assessed, with 45 incidents of clinically confirmed concussion, and 45 cases where no concussion was sustained. Each video was examined using the hierarchical flowchart, and a single response was given for each video based on the highest-ranking element in the flowchart. Results: No protective action, impact seizure, motor incoordination or blank/vacant look were the highest ranked video signs in almost half of the clinically confirmed concussions, but in only 8.8% of non-concussed individuals. The presence of facial injury, clutching at the head and slow to get up were the highest ranked sign in 77.7% of non-concussed individuals. Conclusions: This study suggests that the implementation of a flowchart model could improve timely assessment of concussion, and it identifies the video signs that should trigger automatic removal from play. (C) 2016 Sports Medicine Australia. Published by Elsevier Ltd. All rights reserved.
Metal partitioning dynamics during the oxidation and acidification of sulfidic soil
- Authors: Claff, Salirian , Burton, Edward , Sullivan, Leigh , Bush, Richard
- Date: 2011
- Type: Text , Journal article
- Relation: Chemical Geology Vol. 286, no. 3-4 (2011), p. 146-157
- Full Text: false
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- Description: The oxidation and acidification of sulfidic soil can lead to changes to metal mobility that can have far-reaching environmental consequences. In this study, we examined changes in the partitioning and mobility of Fe, Cr, Cu, Mn, Ni and Zn in four sulfidic soils, due to sulphide oxidation driven acidification, over a 90. day period. These changes were examined using a novel six-step sequential extraction procedure specifically developed for acid sulphate soil materials. The results demonstrate two distinct steps for the mobilisation of metals in disturbed acid sulphate soil materials, associated with (i) oxidation and (ii) acidification. Initially, oxidation causes metals to be redistributed from the "pyritic" and "organic" fractions to the "acid-soluble" fraction. Subsequent acidification, due to exceedance of the acid neutralising capacity of the soil, drives the release of metals to the "labile" fraction. This study demonstrates the importance of these metal pools in understanding the short-term processes which mobilise metals in sulfidic soils. © 2011 Elsevier B.V.
Ambient temperature solubilisation of brown coal in ammonium carbamate ionic liquids
- Authors: Qi, Ying , Verheyen, Vincent , Vijayaraghavan, Ranganathan , MacFarlane, Douglas , Chaffee, Alan
- Date: 2016
- Type: Text , Journal article
- Relation: Fuel Vol. 166, no. (2016), p. 106-115
- Full Text: false
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- Description: Coal solubilisation is often a necessary step for the alternative utilisation of the cheap and abundant brown coal resources in the State of Victoria, Australia, such as producing high quality fuel or chemicals. A series of ionic liquids (ILs), ammonium carbamates, formed by the association of carbon dioxide (CO2) with low molecular weight secondary amines, were investigated as solvents for the solubilisation of Victorian brown coal. The ionic liquid was mixed with a Loy Yang coal at a mass ratio of 20 to 1 (dry basis) for 24 h at ambient temperature. The solubilisation yields of the coal using three such ILs from dimethyl-, diallyl- and dipropyl-amines, respectively, were between 18% and 23%. Repeated solubilisation of the coal with fresh solvent achieved higher yields, with the highest at 66% by the carbamate formed from dimethylamine (DIMCARB). The variations in chemical structure between the products were compared by elemental analysis and a variety of spectroscopic techniques (FTIR, Solid State 13C NMR and Py-GC-MS). The soluble products of the initial solubilisation were more aliphatic than their parent coal. The less polar ILs formed from diallyl- and dipropyl-amines (DACARB and DPCARB) appeared to be more selective for high molecular weight triterpenoids than DIMCARB. Subsequent treatment tended to dissolve more aromatic components. © 2015 Elsevier Ltd. All rights reserved.
Integrating public health and sport management : Sport participation trends 2001-2010
- Authors: Eime, Rochelle , Sawyer, Neroli , Harvey, Jack , Casey, Meghan , Westerbeek, Hans , Payne, Warren
- Date: 2015
- Type: Text , Journal article
- Relation: Sport Management Review Vol. 18, no. 2 (2015), p. 207-217
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- Description: In order to inform strategies to increase levels of physical activity (PA) for a healthier society, it is important to understand participation trends in leisure-time physical activity (LTPA). Little is known about the context of LTPA participation, particularly from the perspective of "sport and recreation" (S&R) categories such as organised and club-based activities. The primary aim of this study is to contribute to the sport management literature by specifically examining PA participation levels and trends in Australia over a decade, for those aged 15 years and older, through the lens of S&R. This paper also discusses the potential synergy between the public health and sport management domains with regard to LTPA/S&R. The Australian Sports Commission provided data from the Exercise, Recreation and Sport Survey (ERASS), a population survey conducted quarterly from 2001 to 2010 by computer-assisted telephone interview. Participation in LTPA was analysed by year, gender and age, in three hierarchically related categories: (1) any LTPA participation, (2) participation in an organised context, and (3) organised participation in a club. Participation rates in any LTPA increased significantly over the decade. However, this was not matched by increases in organised and/or club participation, which largely remained steady over the 10-year period. Much of the organised participation was within a club setting, and participation in this context is more likely among males than females. There is some evidence that the overall level of LTPA is increasing, which is positive for health, but there was generally no increase in club-based participation, resulting in sport contributing relatively less to overall population LTPA. However, the depth of information available from population surveys regarding club-based LTPA is insufficient to draw definitive conclusions, or make important strategic decisions about sport and health policy. There is a critical need for more comprehensive sport participation data to provide the evidence for improved programme and policy development. An avenue for this to occur may be through the integration of participation data from peak sport organisations. (C) 2014 Sport Management Association of Australia and New Zealand. Published by Elsevier Ltd. All rights reserved.
Ritual, remembrance and war: Social memory at Tyne Cot
- Authors: Winter, Caroline
- Date: 2015
- Type: Text , Journal article
- Relation: Annals of Tourism Research Vol. 54, no. September (2015), p. 16-29
- Full Text: false
- Reviewed:
- Description: One of the social memories of the Great War of 1914-1918 focused on soldiers killed in battle, with military cemeteries forming important sites for remembrance. This paper reports the results of an analysis of the visitor books at Tyne Cot Cemetery in Belgium, that was built by the Commonwealth War Graves Commission to hold almost 12,000 graves, most of which contain unidentified remains. Tourist's comments in the books evidenced a strong linguistic ritual, expressing sadness, gratitude, approval of the site and promises to remember and never forget the dead. Very little critique of war, or overt nationalistic sentiment was indicated. While some national preferences for ritualized phrases were shown, there was also an indication of a globally shared memory. © 2015 Elsevier Ltd.
Bone char as a green sorbent for removing health threatening fluoride from drinking water
- Authors: Alkurdi, Susan , Al-Juboori, Raed , Bundschuh, Jochen , Hamawand, Ihsan
- Date: 2019
- Type: Text , Journal article , Review
- Relation: Environment International Vol. 127, no. (2019), p. 704-719
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- Description: Millions of people around the world suffer from or prone to health problems caused by high concentration of fluoride in drinking water sources. One of the environmentally friendly and cost-effective ways for removing fluoride is the use of bone char. In this review, the structural properties and binding affinity of fluoride ions from different water sources was critically discussed. The effect of experimental conditions on enhancing the adsorption capacity of fluoride ions using bone char samples was addressed. It appears that surface properties, and conditions of the bone char production such as temperature and residence time play an important role in designing the optimal fluoride removal process. The optimum temperature for fluoride removal seems to be in the range of 500–700 °C and a residence time of 2 h. Applying various equilibrium adsorption isotherms for understanding fluoride adsorption mechanism was presented. The effect of bone char modification with different elements were discussed and recommendations for a further increase in the removal efficiency was proposed. Cost of bone char production and large-scale treatment systems were also discussed based on information available from scientific and commercial sources. Challenges with existing domestic defluoridation designs were highlighted and suggestions for new conceptual designs were provided.
A sequential extraction procedure for acid sulfate soils : Partitioning of iron
- Authors: Claff, Salirian , Sullivan, Leigh , Burton, Edward , Bush, Richard
- Date: 2010
- Type: Text , Journal article
- Relation: Geoderma Vol. 155, no. 3-4 (2010), p. 224-230
- Full Text: false
- Reviewed:
- Description: A new sequential extraction scheme for acid sulfate soil materials has been evaluated for iron partitioning in a range of synthetic iron-bearing minerals and natural acid sulfate soil materials. This sequential extraction procedure employs six steps to quantify (1) exchangeable (magnesium chloride extractable), (2) acid (hydrochloric acid) soluble, (3) reactive organic-bound (pyrophosphate extractable), (4) crystalline oxide (citrate buffered dithionite (CBD)) extractable, (5) pyrite-bound (nitric acid extractable) and (6) residual (acid/peroxide digestible) forms of iron. Given its intended use for acid sulfate soil materials that frequently contain pyrite, a primary aim of this new sequential extraction procedure was to differentiate iron bound in pyrite from iron contained in other minerals. The results demonstrated that dissolution of pyrite was effectively isolated in the pyrite-bound extraction step, with dissolution of other iron mineral phases (i.e. akaganeite, ferrihydrite, goethite, hematite, jarosite, magnetite, and schwertmannite) occurring within the other five extraction steps. Following a systematic examination of these synthetic iron mineral phases, the sequential extraction scheme was applied to an acid sulfate soil profile, with detailed data presented for two soil layers: one representative of the sulfidic (unoxidised) conditions, and the other sulfuric (oxidised) conditions. Partitioning data for pyrite-bound iron in the acid sulfate soil profile showed good agreement with that calculated via the independently measured pyrite-bound reduced sulfur. This study indicates that the new sequential extraction procedure is suitable for the assessment of iron partitioning in acid sulfate soil materials. © 2009 Elsevier B.V. All rights reserved.
Rating teams’ non-technical skills in the emergency department : A qualitative study of nurses’ experience
- Authors: Porter, Joanne , Cant, Robyn , Cooper, Simon J.
- Date: 2018
- Type: Text , Journal article
- Relation: International Emergency Nursing Vol. 38, no. (2018), p. 15-20
- Full Text: false
- Reviewed:
- Description: Introduction: Non-technical skills (NTS) teamwork training can enhance clinicians’ understanding of roles and improve communication. We evaluated a quality improvement project rating teams’ NTS performance to determine the value of formal rating and debriefing processes. Methods: In two Australian emergency departments the NTS of resuscitation teams were rated by senior nurses and medical staff. Key measures were leadership, teamwork, and task management using a valid instrument: Team Emergency Assessment Measure (TEAM™). Emergency nurses were asked to attend a focus group from which key themes around the quality improvement process were identified. Results: Main themes were: ‘Team composition’ (allocation of resuscitation team roles), ‘Resuscitation leadership’ (including both nursing and medical leadership roles) and ‘TEAM™ ratings promote reflective practice’ (providing staff a platform to discuss team effectiveness). Objective ratings were seen as enabling staff to provide feedback to other team members. Reflection on practice and debriefing were thought to improve communication, help define roles and responsibilities, and clarify leadership roles. Conclusion: Use of a non-technical skills rating scheme such as TEAM™ after team-based clinical resuscitation events was seen by emergency department nurses as feasible and a useful process for examining and improving multi-disciplinary practice, while improving team performance. © 2018 Elsevier Ltd
Modeling of multi-junction photovoltaic cell using MATLAB/Simulink to improve the conversion efficiency
- Authors: Das, Narottam , Wongsodihardjo, Hendy , Islam, Syed
- Date: 2015
- Type: Text , Journal article
- Relation: Renewable Energy Vol. 74, no. (2015), p. 917-924
- Full Text: false
- Reviewed:
- Description: This paper focuses on modeling of multi-junction solar cell (MJSC) to improve the conversion efficiency using MATLAB/Simulink software. The multi-junction photovoltaic (PV) cell is investigated to obtain its maximum performance compare to the conventional silicon PV cell. MATLAB/Simulink modeled results show that tandem cell can provide almost 3-times maximum power compared to the conventional PV cells. Maximum power point tracker (MPPT) has also been performed to improve the conversion efficiency of the PV systems. The MPPT is able to assist the PV cells to attain more power efficiently and deliver electricity to the grid.
Effect of sample pretreatment on the fractionation of Fe, Cr, Ni, Cu, Mn, and Zn in acid sulfate soil materials
- Authors: Claff, Salirian , Burton, Edward , Sullivan, Leigh , Bush, Richard
- Date: 2010
- Type: Text , Journal article
- Relation: Geoderma Vol. 159, no. 1-2 (2010), p. 156-164
- Full Text: false
- Reviewed:
- Description: A sequential extraction procedure was applied to acid sulfate soil materials from a soil profile to investigate the effect of sample pretreatment on the geochemical fractionation of selected metals. The samples were prepared for analysis by oven-drying, sieving and grinding the soil, or were examined as collected in field condition. The soil profile encompassed oxidising conditions near the surface, through to reducing conditions at depth. Six metals (Fe, Cr, Ni, Mn, Cu, and Zn) were measured during the sequential extraction procedure, and their fractionation determined in the oxidised and in the reduced zone. Although cumulative totals (the sum of all steps in the sequential extraction procedure) for the metals extracted from both the field condition and dried/ground samples were similar, some significant differences in fractionation within individual extraction steps were observed. Of particular interest was the redistribution of metals from the sulfide-bearing (pyrite-bound) fraction to the more readily available fractions (i.e. labile and acid-soluble), as a result of oven-drying and grinding. The results indicate that when assessing metal fractionation in acid sulfate soil materials, samples should be analysed in field condition in order to avoid the considerable metal fractionation artifacts that are induced by drying and grinding. © 2010 Elsevier B.V.
An initial experimental assessment of the influence of substrate depth on floral assemblage for extensive green roofs
- Authors: Olly, Luke , Bates, Adam , Sadler, Jon , Mackay, Rae
- Date: 2011
- Type: Text , Journal article
- Relation: Urban Forestry and Urban Greening Vol. 10, no. 4 (2011), p. 311-316
- Full Text: false
- Reviewed:
- Description: Extensive green roofs have the potential to be used as mitigation tools to compensate for urban habitat loss, but there is little information about how closely these systems emulate ground-based habitats. This study investigated the effect of limited substrate depth on plant assemblages in the initial phase of growth in extensive green roof substrates. Five replicate mesocosms (1m 2) for each of three design treatments: (A) 10cm aggregate depth with green roof drainage and solid floor, (B) 15cm aggregate depth with green roof drainage and solid floor, and (C) 15cm aggregate depth on top of bare earth; were positioned at ground level. Each mesocosm had an identical growth substrate and was seeded with the same seed mix. Plant assemblages were analysed using point-quadrat methods. Significant differences in species composition were observed between treatments that seemed to be related to water availability. Even the deep (15cm) solid floor green roof treatment showed many significant differences in floral assemblage compared to the identical treatment (C) where plants had access to water in the soil profile. Therefore, it is not possible to exactly recreate most ground-based urban habitats on roofs by simply copying the soil characteristics and floral composition found on the ground. Like for mitigation for habitat loss using extensive green roofs requires the careful manipulation of design elements in order to counteract the limited water availability on green roofs. © 2011 Elsevier GmbH.