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Sports-related workload and injury risk : Simply knowing the risks will not prevent injuries : Narrative review

  • Authors: Drew, Michael , Cook, Jill , Finch, Caroline
  • Date: 2016
  • Type: Text , Journal article , Review
  • Relation: British Journal of Sports Medicine Vol. 50, no. 21 (2016), p. 1306-1309
  • Relation: http://purl.org/au-research/grants/nhmrc/1058737
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  • Description: Training loads contribute to sports injury risk but their mitigation has rarely been considered in a sports injury prevention framework. A key concept behind monitoring training loads for injury prevention is to screen for those at increased risk of injury so that workloads can be adjusted to minimise these risks. This review describes how advances in management of workload can be applied as a preventive measure. Primary prevention involves screening for preparticipation load risk factors, such as low training loads, prior to a training period or competition. Secondary prevention involves screening for workloads that are known to precede an injury developing so that modification can be undertaken to mitigate this risk. Tertiary prevention involves rehabilitation practices that include a graded return to training programme to reduce the risk of sustaining a subsequent injury. The association of training loads with injury incidence is now established. Prevention measures such as rule changes that affect the workload of an athlete are universal whereas those that address risk factors of an asymptomatic subgroup are more selective. Prevention measures, when implemented for asymptomatic individuals exhibiting possible injury risk factors, are indicated for an athlete at risk of developing a sports injury. Seven key indicated risks and associated prevention measures are proposed.

Statistical downscaling of general circulation model outputs to precipitation, evaporation and temperature using a key station approach

  • Authors: Sachindra, Dhanapala , Huang, Fuchun , Barton, Andrew , Perera, Bimalka
  • Date: 2016
  • Type: Text , Journal article
  • Relation: Journal of Water and Climate Change Vol. 7, no. 4 (2016), p. 683-707
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  • Description: Using a key station approach, statistical downscaling of monthly general circulation model outputs to monthly precipitation, evaporation, minimum temperature and maximum temperature at 17 observation stations located in Victoria, Australia was performed. Using the observations of each predictand, over the period 1950-2010, correlations among all stations were computed. For each predictand, the station which showed the highest number of correlations above 0.80 with other stations was selected as the first key station. The stations that were highly correlated with that key station were considered as the member stations of the first cluster. By employing this same procedure on the remaining stations, the next key station was found. This procedure was performed until all stations were segregated into clusters. Thereafter, using the observations of each predictand, regression equations (inter-station regression relationships) were developed between the key stations and the member stations for each calendar month. The downscaling models at the key stations were developed using reanalysis data as inputs to them. The outputs of HadCM3 pertaining to A2 emission scenario were introduced to these downscaling models to produce projections of the predictands over the period 2000-2099. Then the outputs of these downscaling models were introduced to the inter-station regression relationships to produce projections of predictands at all member stations.

Tendon neuroplastic training : Changing the way we think about tendon rehabilitation : A narrative review

  • Authors: Rio, Ebonie , Kidgell, Dawson , Lorimer Moseley, Graham , Gaida, Jamie , Docking, Sean , Purdam, Craig , Cook, Jill
  • Date: 2016
  • Type: Text , Journal article
  • Relation: British Journal of Sports Medicine Vol. 50, no. 4 (2016), p. 209-215
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  • Description: Tendinopathy can be resistant to treatment and often recurs, implying that current treatment approaches are suboptimal. Rehabilitation programmes that have been successful in terms of pain reduction and return to sport outcomes usually include strength training. Muscle activation can induce analgesia, improving self-efficacy associated with reducing one's own pain. Furthermore, strength training is beneficial for tendon matrix structure, muscle properties and limb biomechanics. However, current tendon rehabilitation may not adequately address the corticospinal control of the muscle, which may result in altered control of muscle recruitment and the consequent tendon load, and this may contribute to recalcitrance or symptom recurrence. Outcomes of interest include the effect of strength training on tendon pain, corticospinal excitability and short interval cortical inhibition. The aims of this concept paper are to: (1) review what is known about changes to the primary motor cortex and motor control in tendinopathy, (2) identify the parameters shown to induce neuroplasticity in strength training and (3) align these principles with tendon rehabilitation loading protocols to introduce a combination approach termed as tendon neuroplastic training. Strength training is a powerful modulator of the central nervous system. In particular, corticospinal inputs are essential for motor unit recruitment and activation; however, specific strength training parameters are important for neuroplasticity. Strength training that is externally paced and akin to a skilled movement task has been shown to not only reduce tendon pain, but modulate excitatory and inhibitory control of the muscle and therefore, potentially tendon load. An improved understanding of the methods that maximise the opportunity for neuroplasticity may be an important progression in how we prescribe exercise-based rehabilitation in tendinopathy for pain modulation and potentially restoration of the corticospinal control of the muscle-tendon complex.

The impact of handwriting difficulties on compositional quality in children with developmental coordination disorder

  • Authors: Prunty, Mellissa , Barnett, Anna , Wilmut, Kate , Plumb, Mandy
  • Date: 2016
  • Type: Text , Journal article
  • Relation: British Journal of Occupational Therapy Vol. 79, no. 10 (2016), p. 591-597
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  • Description: Introduction There is substantial evidence to support the relationship between transcription skills (handwriting and spelling) and compositional quality. For children with developmental coordination disorder, handwriting can be particularly challenging. While recent research has aimed to investigate their handwriting difficulties in more detail, the impact of transcription on their compositional quality has not previously been examined. The aim of this exploratory study was to examine compositional quality in children with developmental coordination disorder and to ascertain whether their transcription skills influence writing quality. Method Twenty-eight children with developmental coordination disorder participated in the study, with 28 typically developing age and gender matched controls. The children completed the free-writing' task from the detailed assessment of speed of handwriting tool, which was evaluated for compositional quality using the Wechsler objective language dimensions. Results The children with developmental coordination disorder performed significantly below their typically developing peers on five of the six Wechsler objective language dimensions items. They also had a higher percentage of misspelled words. Regression analyses indicated that the number of words produced per minute and the percentage of misspelled words explained 55% of the variance for compositional quality. Conclusion The handwriting difficulties so commonly reported in children with developmental coordination disorder have wider repercussions for the quality of written composition.

Visual perceptual and handwriting skills in children with developmental coordination disorder

  • Authors: Prunty, Mellissa , Barnett, Anna , Wilmut, Kate , Plumb, Mandy
  • Date: 2016
  • Type: Text , Journal article
  • Relation: Human Movement Science Vol. 49, no. (2016), p. 54-65
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  • Description: Objective: Children with Developmental Coordination Disorder demonstrate a lack of automaticity in handwriting as measured by pauses during writing. Deficits in visual perception have been proposed in the literature as underlying mechanisms of handwriting difficulties in children with DCD. The aim of this study was to examine whether correlations exist between measures of visual perception and visual motor integration with measures of the handwriting product and process in children with DCD. Method: The performance of twenty-eight 8-14 year-old children who met the DSM-5 criteria for DCD was compared with 28 typically developing (TD) age and gender-matched controls. The children completed the Developmental Test of Visual Motor Integration (VMI) and the Test of Visual Perceptual Skills (TVPS). Group comparisons were made, correlations were conducted between the visual perceptual measures and handwriting measures and the sensitivity and specificity examined. Results: The DCD group performed below the TD group on the VMI and TVPS. There were no significant correlations between the VMI or TVPS and any of the handwriting measures in the DCD group. In addition, both tests demonstrated low sensitivity. Conclusion: Clinicians should execute caution in using visual perceptual measures to inform them about handwriting skill in children with DCD. © 2016 The Authors.

Vitamins in brewing : Effects of post-fermentation treatments and exposure and maturation on the thiamine and riboflavin vitamer content of beer

  • Authors: Hucker, Barry , Vriesekoop, Frank , Vriesekoop-Beswick, Arielle , Wakeling, Lara , Vriesekoop-Besick, Hamish , Hucker, Amy
  • Date: 2016
  • Type: Text , Journal article
  • Relation: Journal of the Institute of Brewing Vol. 122, no. 2 (2016), p. 278-288
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  • Description: Post-fermentation processes and maturation are important steps in beer production as they help to shape the organoleptic properties and stabilize the final product. Brewers can use a variety of processing aids (e.g. isinglass, PVPP, etc.) and processes (e.g. pasteurization, bottle conditioning, etc.) to achieve a desired final product with a desirable shelf life; however, these processes can have detrimental effects on the vitamin content of the beer. This research found that heat treatments have a marked influence on the decrease in the thiamine diphosphate vitamer, while PVPP and silica treatments have a greater influence on the decrease in riboflavin vitamers. Refrigeration, filtration or centrifugation have no, or only very limited, influence on thiamine or riboflavin vitamers, while application of isinglass, bentonite, tannic acid and SO2 causes a decrease in both thiamine and riboflavin vitamers. Storage of beer at refrigerated temperatures appears to provide protection against significant degradation of both thiamine and riboflavin vitamers; however, storage of filtered beer at elevated temperatures shows a decrease in thiamine diphosphate and riboflavin. Storage of bottle-conditioned beer at elevated temperatures shows a marked decrease in yeast viability, accompanied by a decrease in thiamine diphosphate and free riboflavin, and a marked increase in free thiamine. These findings provide an insight into the reason why there is a significant variation in the vitamer content of beers, even within a single beer style. © 2016 The Institute of Brewing & Distilling.

A 3D object encryption scheme which maintains dimensional and spatial stability

  • Authors: Jolfaei, Alireza , Wu, Xinwen , Muthukkumarasamy, Vallipuram
  • Date: 2015
  • Type: Text , Journal article
  • Relation: IEEE Transactions on Information Forensics and Security Vol. 10, no. 2 (2015), p. 409-422
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  • Description: Due to widespread applications of 3D vision technology, the research into 3D object protection is primarily important. To maintain confidentiality, encryption of 3D objects is essential. However, the requirements and limitations imposed by 3D objects indicate the impropriety of conventional cryptosystems for 3D object encryption. This suggests the necessity of designing new ciphers. In addition, the study of prior works indicates that the majority of problems encountered with encrypting 3D objects are about point cloud protection, dimensional and spatial stability, and robustness against surface reconstruction attacks. To address these problems, this paper proposes a 3D object encryption scheme, based on a series of random permutations and rotations, which deform the geometry of the point cloud. Since the inverse of a permutation and a rotation matrix is its transpose, the decryption implementation is very efficient. Our statistical analyses show that within the cipher point cloud, points are randomly distributed. Furthermore, the proposed cipher leaks no information regarding the geometric structure of the plain point cloud, and is also highly sensitive to the changes of the plaintext and secret key. The theoretical and experimental analyses demonstrate the security, effectiveness, and robustness of the proposed cipher against surface reconstruction attacks.

A comprehensive spectrum trading scheme based on market competition, reputation and buyer specific requirements

  • Authors: Hassan, Md Rakib , Karmakar, Gour , Kamruzzaman, Joarder , Srinivasan, Bala
  • Date: 2015
  • Type: Text , Journal article
  • Relation: Computer Networks Vol. 84, no. (2015), p. 17-31
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  • Description: In the exclusive-use model of spectrum trading, cognitive radio devices or secondary users can buy spectrum resources from licensed users or primary users for a short or long period of time. Considering such spectrum access, a trading model is introduced where a buyer can select a set of candidate sellers based on their reputation and their offers in fulfilling its requirements, namely, offered signal quality, contract duration, coverage and bandwidth. Similarly, a seller can assess a buyer as a potential trading partner considering the buyer's reliability, which the seller can derive from the buyer's reputation and financial profile. In our scheme, seller reputation or buyer reliability can be either obtained from a reputation brokerage service, if one exists, or calculated using our model. Since in a competitive market, the price of a seller depends on that of other sellers, game theory is used to model the competition among multiple sellers. An optimization technique is used by a buyer to select the best seller(s) and optimize purchase to maximize its utility. This may result in buying from multiple sellers of certain amount of bandwidth from each, depending on price and meeting requirements and budget constraints. Stability of the model is analyzed and performance evaluation shows that it benefits sellers and buyers in terms of profit and throughput, respectively. © 2015 Elsevier B.V. All rights reserved.

A DEM investigation on simple shear behavior of dense granular assemblies

  • Authors: Shi, Danda , Xue, Jianfeng , Zhao, Zhenying , Shi, Jiyu
  • Date: 2015
  • Type: Text , Journal article
  • Relation: Journal of Central South University Vol. 22, no. 12 (2015), p. 4844-4855
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  • Description: A micromechanical investigation on simple shear behavior of dense granular assemblies was carried out by discrete element method. Three series of numerical tests were performed to examine the effects of initial porosity, vertical stress and particle shape on simple shear behavior of the samples, respectively. It was found that during simple shear the directions of principal stress and principal strain increment rotate differently with shear strain level. The non-coaxiality between the two directions decreases with strain level and may greatly affect the shear behavior of the assemblies, especially their peak friction angles. The numerical modelling also reveals that the rotation of the principal direction of fabric anisotropy lags behind that of the major principal stress direction during simple shear, which is described as fabric hyteresis effect. The degrees of fabric and interparticle contact force anisotropies increase as particle angularity increases, whereas the orientations of these anisotropies have not been significantly influenced by particle shape. An extended stress-dilatancy relationship based on ROWE-DAVIS framework was proposed to consider the non-coaxiality effect under principal stress rotation. The model was validated by present numerical results as well as some published physical test and numerical modelled data. © 2015, Central South University Press and Springer-Verlag Berlin Heidelberg.

A new modified FMEA model for ranking the risk of maintenance waste considering hierarchy of root causes and effects

  • Authors: Sutrisno, Agung , Gunawan, Indra , Khorshidi, Hadi , Tangkuman, Stenly
  • Date: 2015
  • Type: Text , Journal article
  • Relation: International Journal of Quality Engineering and Technology Vol. 5, no. 3-4 (2015), p. 217-237
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  • Description: Implementing sustainable manufacturing practice requires efficiency of the resource utilisation and activities which add value to the operations. From this point of view, development of an improved methodology to access the criticality of non- Added value (waste) is important and believed to support the realisation of sustainable manufacturing operation. While previous studies on improving methodology to support sustainable operation from product and process design are abundantly available in the references, the contribution from maintenance field is in contrary. The goal of this study is to modify the quality improvement tool, failure mode and effect analysis (FMEA) to access the criticality of waste in maintenance operation. In an attempt to realise the above goal, an empirical study to propose the theoretical and actual maintenance waste from industrial practice is undertaken. In order to assist maintenance 218 A. Sutrisno et al. decision maker to quantify criticality of maintenance waste occurrence, a new model to rank waste maintenance mode, called the waste priority number (WPN) is given. Illustrative on using model for practical purpose is given.. © 2015 Inderscience Enterprises Ltd.

A new reliability analysis method based on the conjugate gradient direction

  • Authors: Ezzati, Ghasem , Mammadov, Musa , Kulkarni, Siddhivinayak
  • Date: 2015
  • Type: Text , Journal article
  • Relation: Structural and Multidisciplinary Optimization Vol. 51, no. 1 (2015), p. 89-98
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  • Description: Reliability-based design optimization (RBDO) is an important area in structural optimization. A principal step of the RBDO process is to solve a reliability analysis problem. This problem has been considered in inner loop of double-loop RBDO approaches. Although many algorithms have been developed for solving this problem, there are still some challenges. Existing algorithms do not have good convergence rates and often diverge. There is a need to develop more efficient and stable algorithms that can be used for evaluating all performance functions sufficiently. In this paper, a new method, called “Conjugate Gradient Analysis (CGA) Method”, is proposed to apply in the reliability analysis problems. This method is based on the conjugate gradient method. Some mathematical problems are provided in order to demonstrate the advantages of the proposed method compared with the existing methods. © 2014, Springer-Verlag Berlin Heidelberg.

A novel motion classification based intermode selection strategy for HEVC performance improvement

  • Authors: Podder, Pallab , Paul, Manoranjan , Murshed, Manzur
  • Date: 2015
  • Type: Text , Journal article
  • Relation: Neurocomputing Vol. 173, no. Part 3 (2015), p. 1211-1220
  • Relation: http://purl.org/au-research/grants/arc/DP130103670
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  • Description: High Efficiency Video Coding (HEVC) standard adopts several new approaches to achieve higher coding efficiency (approximately 50% bit-rate reduction) compared to its predecessor H.264/AVC with same perceptual image quality. Huge computational time has also increased due to the algorithmic complexity of HEVC compared to H.264/AVC. However, it is really a demanding task to reduce the encoding time while preserving the similar quality of the video sequences. In this paper, we propose a novel efficient intermode selection technique and incorporate into HEVC framework to predict motion estimation and motion compensation modes between current and reference blocks and perform faster inter mode selection based on three dissimilar motion types in divergent video sequences. Instead of exploring and traversing all the modes exhaustively, we merely select a subset of candidate modes and the final mode from the selected subset is determined based on their lowest Lagrangian cost function. The experimental results reveal that average encoding time can be downscaled by 40% with similar rate-distortion performance compared to the exhaustive mode selection strategy in HEVC.
  • Description: High Efficiency Video Coding (HEVC) standard adopts several new approaches to achieve higher coding efficiency (approximately 50% bit-rate reduction) compared to its predecessor H.264/AVC with same perceptual image quality. Huge computational time has also increased due to the algorithmic complexity of HEVC compared to H.264/AVC. However, it is really a demanding task to reduce the encoding time while preserving the similar quality of the video sequences. In this paper, we propose a novel efficient intermode selection technique and incorporate into HEVC framework to predict motion estimation and motion compensation modes between current and reference blocks and perform faster inter mode selection based on three dissimilar motion types in divergent video sequences. Instead of exploring and traversing all the modes exhaustively, we merely select a subset of candidate modes and the final mode from the selected subset is determined based on their lowest Lagrangian cost function. The experimental results reveal that average encoding time can be downscaled by 40% with similar rate-distortion performance compared to the exhaustive mode selection strategy in HEVC. © 2015 Elsevier B.V.

Boxing headguard performance in punch machine tests

  • Authors: McIntosh, Andrew , Patton, Declan
  • Date: 2015
  • Type: Text , Journal article
  • Relation: British Journal of Sports Medicine Vol. 49, no. 17 (2015), p. 1108-1112
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  • Description: Background: The paper presents a novel laboratory method for assessing boxing headguard impact performance. The method is applied to examine the effects of headguards on head impact dynamics and injury risk. Methods: A linear impactor was developed, and a range of impacts was delivered to an instrumented Hybrid III head and neck system both with and without an AIBA (Association Internationale de Boxe Amateur)- approved headguard. Impacts at selected speeds between 4.1 and 8.3 m/s were undertaken. The impactor mass was approximately 4 kg and an interface comprising a semirigid 'fist' with a glove was used. Results: The peak contact forces were in the range 1.9-5.9 kN. Differences in head impact responses between the Top Ten AIBA-approved headguard and bare headform in the lateral and forehead tests were large and/or significant. In the 8.3 m/s fist-glove impacts, the mean peak resultant headform accelerations for bare headform tests was approximately 130 g compared with approximately 85 g in the forehead impacts. In the 6.85 m/s bare headform impacts, mean peak resultant angular head accelerations were in the range of 5200-5600 rad/s

Caution this drug may cause serious harm! why we must report adverse effects of physical activity promotion

Competing with injuries : Injuries prior to and during the 15th FINA World Championships 2013 (aquatics)

  • Authors: Mountjoy, Margo , Junge, Astrid , Benjamen, Sarah , Boyd, Kevin , Diop, Mohamed , Gerrard, David , van den Hoogenband, Cees-Rein , Marks, Saul , Martinez-Ruiz, Enrique , Miller, Jim , Nanousis, Kyriakos , Shahpar, Farhad , Veloso, Jose , van Mechelen, Willem , Verhagen, Evert
  • Date: 2015
  • Type: Text , Journal article
  • Relation: British Journal of Sports Medicine Vol. 49, no. 1 (2015), p. 37-43
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  • Description: Background: Injury and illness surveillance is the foundation for the development of prevention strategies. Objective: To examine injuries among the aquatic disciplines in the 4 weeks prior to and during the 2013 FINA World Championships. Methods: The study was comprised of two components: (1) a retrospective athlete survey recording injuries in the 4 weeks prior to the Championships and (2) a prospective recording of injuries and illnesses by the medical teams of the participating countries and the local host medical team. Results: One-third of the 1116 responding athletes reported an injury/physical complaint in the 4 weeks prior to the Championships. Significantly more women (36.7%) than men (28.6%) reported injuries. Divers reported the highest rate of injury/physical complaints (55.7%). At the start of the Championships, 70% of injured respondents (n=258) were still symptomatic; however, full participation was expected by 76%. During the Championships, 186 new injuries were reported (8.3/100 registered athletes) with the highest injury incidence rate in water polo (15.3/100 registered athletes). The most common injured body part was the shoulder (21%). A total of 199 illnesses were reported during the Championships (9.0/100 registered athletes) with the most common diagnosis of illness being gastrointestinal infection. Environmental exposure (allergy, otitis and jellyfish stings) was responsible for 27% of all illnesses in open water swimming. Conclusions: Injuries pose a significant health risk for elite aquatic athletes. A prospective study would improve understanding of out-of-competition injuries. Future injury and illness surveillance at FINA World Championships is required to direct and measure the impact of prevention strategies.

Effect of physicochemical properties on freezing suitability of Lotus (Nelumbo nucifera) root

  • Authors: Tu, Jing , Zhang, Min , Xu, Baoguo , Liu, Amy
  • Date: 2015
  • Type: Text , Journal article
  • Relation: International Journal of Refrigeration Vol. 50, no. (2015), p. 1-9
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  • Description: The initial physicochemical properties of different lotus roots were studied with the aim to evaluate their influence on freezing suitability. Six physicochemical properties indicators (starch content, whiteness index, maximum diameter, protein amount, titratable acidity and vitamin C) of lotus root were determined by principal component analysis. It was observed from the experimental results that the initial physicochemical properties of lotus root can directly affect the freezing suitability in terms of initial freezing temperature, transition phase time, total freezing time, relative firmness and drip loss. Correlation analysis suggested that relative firmness increases in proportion to starch content, and initial freezing temperature and drip loss are inversely proportional to the starch content. Compared to immersion freezing, power ultrasound can significantly improve the freezing rate and relative firmness but decrease drip loss. These results suggested that high quality frozen lotus root can be achieved via appropriately selecting high starch content lotus root and using ultrasound-assisted immersion freezing.

Effects of different freezing methods on the quality and microstructure of lotus (Nelumbo nucifera) root

  • Authors: Tu, Jing , Zhang, Min , Xu, Baoguo , Liu, Huihua
  • Date: 2015
  • Type: Text , Journal article
  • Relation: International Journal of Refrigeration Vol. 52, no. (2015), p. 59-65
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  • Description: The effects of three freezing methods, air blast freezing (ABF), immersion freezing (IF) and ultrasound-assisted immersion freezing (UIF), on quality and microstructure of lotus roots were investigated. The parameters used to evaluate the freezing methods effect were the freezing time, color, firmness, drip loss, vitamin C and microstructure of the final frozen products. The results showed that the UIF products had several advantages in terms of the freezing time, color, firmness and drip loss over ABF and IF. No significant difference (p > 0.05) of vitamin C content was observed between the ABF and IF products, while significant difference (p < 0.05) of vitamin C was observed between UIF and ABF/IF products. ABF caused the largest destruction to the tissue, while the microstructure of the UIF products was the best preserved. It is concluded that UIF processing was a better freezing method for lotus root with improved quality and less damaged microstructure than the two other methods. © 2014 Elsevier Ltd and IIR.

Effects of recycled aggregate growth substrate on green roof vegetation development: A six year experiment

  • Authors: Bates, Adam , Sadler, Jon , Greswell, Richard , Mackay, Rae
  • Date: 2015
  • Type: Text , Journal article
  • Relation: Landscape and Urban Planning Vol. 135, no. (2015), p. 22-31
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  • Description: Green roofs have the potential to address several of the environmental problems associated with urbanisation, and can be used as mitigation for habitats lost at ground level. Brown roofs (a type of green roof) can be used to mitigate for the loss of brownfield habitat, but the best way of designing these habitats remains unclear. This paper reports an experiment to test the effects of different types of recycled aggregate on the development of vegetation assemblages on brown roof mesocosms. Five recycled aggregates were tested: (1) crushed brick, (2) crushed demolition aggregate, (3) solid municipal waste incinerator bottom ash aggregate, (4) a 1:1 mix of 1 and 2, and (5) a 1:1 mix of 3 and 2. Each was seeded with a wildflower mix that also included some Sedum acre and vegetation development was studied over a six-year period. Species richness, assemblage character, number of plants able to seed, and plant biomass were measured. Drought disturbance was the key factor controlling changes in plant assemblage, but effects varied with substrate treatment. All treatments supported a similar plant biomass, but treatments with a high proportion of crushed brick in the growth substrate supported richer assemblages, with more species able to seed, and a smaller amount of Sedum acre. Crushed brick, or recycled aggregates with a high proportion of crushed brick, are recommended as good growth substrate materials for encouraging brown roof plant diversity. This investigation demonstrates the importance of multi-year studies of green roof development for the generation of robust findings.

Electrokinetics to modify strength characteristics of soft clayey soils : A laboratory based investigation

  • Authors: Jayasekera, Samudra
  • Date: 2015
  • Type: Text , Journal article
  • Relation: Electrochimica Acta Vol. 181, no. (2015), p. 39-47
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  • Description: The effects of Electrokinetic (EK) processing on compressive strength characteristics of two types of soils were investigated using laboratory experimental models. Soils were collected from soft alluvial soil deposit (Soil S1) and basaltic soil deposit (Soil S2) in central Victoria, Australia. A layer of soil was placed in glass tanks (90 cm × 18 cm plan area) and compacted to a known density and water content typical of field conditions. Using electrodes inserted into the soil, a direct current was passed across the soil under various voltage gradients (0.5, 1.0, 2.0 V/cm) for periods of 7, 14, 30 and 60 days. Throughout the experimental duration, test samples were supplied with a continuous flow of water via the hollow core anode from external reservoirs. Unconfined compression (UC) tests were conducted on original (untreated) soils and EK processed soils. From the test results it is noted that, soil compressive strength increases with the increasing processing time and increasing voltage gradients, at various rates. Under certain voltage gradients and processing times, around 175% and 200% strength increases are observed. In general, stress increases of at least 30% or more are reported for both soils under all test conditions. It is apparent that the variation in strength can be attributed to several complex and interrelated processes that become active under EK processing. These may include, (i) Electroosmotic advection - When a soil is subjected to EK processing with an open electrode configuration, the water content of the soil varies predominantly due to the electroosmotic advection while natural drying and evaporation could also add to the decrease in water content to some extent, depending on the time and environmental conditions such as temperature and humidity. The test results show that with the decrease in water content, there is a corresponding increase in the strength. (ii) Electromigration - The electromigration of charged ions and their interaction with clay minerals can also affect the soil strength due to the variations in the DDL (Diffused Double Layer) ionic concentration and subsequent modifications in the soil structure. (iii) Ionic Diffusion and Aging - After the complete termination of EK processes, the ionic concentrations still continued to modify at a slower rate. This is considered to be due to the ionic diffusion. In this phase too, cementation bonds may continue to develop that could contribute to the increase in soil strength. During this period, two other processes, i.e. natural drying of soil and aging may continue that can also affect the variation of soil strength. © 2015 Elsevier Ltd. All rights reserved.

Evaluation of methods for monitoring MEA degradation during pilot scale post-combustion capture of CO