Multi-agent systems for modeling high penetration photovoltaic system impacts in distribution networks

This paper reviews the use of multi-agent systems to model the impacts of high levels of photovoltaic (PV) system penetration in distribution networks and presents some preliminary data obtained from the Perth Solar City high penetration PV trial. The Perth Solar City trial consists of a low voltage distribution feeder supplying 75 customers where 29 consumers have roof top photovoltaic systems. Data is collected from smart meters at each consumer premises, from data loggers at the transformer low voltage (LV) side and from a nearby distribution network SCADA measurement point on the high voltage side (HV) side of the transformer. The data will be used to progressively develop MAS models.

Perturbed Lignification Impacts Tree Growth in Hybrid Poplar-A Function of Sink Strength, Vascular Integrity, and Photosynthetic Assimilation

The effects of reductions in cell wall lignin content, manifested by RNA interference suppression of coumaroyl 3'-hydroxylase, on plant growth, water transport, gas exchange, and photosynthesis were evaluated in hybrid poplar trees (Populus alba 3 grandidentata). The growth characteristics of the reduced lignin trees were significantly impaired, resulting in smaller stems and reduced root biomass when compared to wild-type trees, as well as altered leaf morphology and architecture. The severe inhibition of cell wall lignification produced trees with a collapsed xylem phenotype, resulting in compromised vascular integrity, and displayed reduced hydraulic conductivity and a greater susceptibility to wall failure and cavitation. In the reduced lignin trees, photosynthetic carbon assimilation and stomatal conductance were also greatly reduced, however, shoot xylem pressure potential and carbon isotope discrimination were higher and water-use efficiency was lower, inconsistent with water stress. Reductions in assimilation rate could not be ascribed to increased stomatal limitation. Starch and soluble sugars analysis of leaves revealed that photosynthate was accumulating to high levels, suggesting that the trees with substantially reduced cell wall lignin were not carbon limited and that reductions in sink strength were, instead, limiting photosynthesis.

Protecting World Heritage sites from the adverse impacts of climate change : obligations for States Parties to the World Heritage Convention

Through its mandate to protect and preserve places of ‘outstanding universal value’, the World Heritage Convention provides an unlikely yet effective tool in global efforts to mitigate climate change. The practical efficacy of the Strategy to Assist States Parties to Implement Appropriate Management Responses (‘the Strategy’), which represents the World Heritage Committee’s primary response to the threats posed by climate change to World Heritage sites, is undermined by its weak stance on mitigation. This paper argues that the World Heritage Convention imposes stronger obligations on States Parties than those contained in the Strategy, including a duty on States Parties to commit to ‘deep cuts’ in greenhouse gas emissions. In order to ensure the continuing success of the World Heritage Convention States Parties must engage in extensive mitigation strategies without delay.

Stabilization of stormwater biofilters: Impacts of wetting and drying phases and the addition of organic matter to filter media

Ripening period refers to a phase of stabilization in sand filters in water treatment systems that follows a new installation or cleaning of the filter. Intermittent wetting and drying, a unique property of stormwater biofilters, would similarly be subjected to a phase of stabilization. Suspended solids, is an important parameter that is often used to monitor the stabilization of sand filters in water treatment systems. Stormwater biofilters however, contain organic material that is added to the filter layer to enhance nitrate removal, the dynamics of which is seldom analysed in stabilization of stormwater biofilters. Therefore, in this study of stormwater biofiltration in addition to suspended solids (Turbidity), organic matter (TOC, DOC, TN and TKN) was also monitored as a parameter for stabilization of the stormwater biofilter. One Perspex bioretention column (94 mm internal diameter) was fabricated with filter layer that contained 8% organic material and fed with tapwater with different antecedent dry days (0 – 40 day) at 100 mL/min. Samples were collected from the outflow at different time intervals between 2 – 150 minutes and were tested for Total Organic Carbon, Dissolved Organic Carbon, Total Nitrogen, Total Kjeldhal Nitrogen and Turbidity. The column was observed to experience two phases of stabilization, one at the beginning of each event that lasted for 30 minutes while the other phase was observed across subsequent events that related to the age of filter.

Hydraulic conductivity increases in a sodic clay soil in response to gypsum applications impacts of bulk density and cation exchange

Amelioration of sodic soils is commonly achieved by applying gypsum, which increases soil hydraulic conductivity by altering soil chemistry. The magnitude of hydraulic conductivity increases expected in response to gypsum applications depends on soil properties including clay content, clay mineralogy, and bulk density. The soil analyzed in this study was a kaolinite rich sodic clay soil from an irrigated area of the Lower Burdekin coastal floodplain in tropical North Queensland, Australia. The impact of gypsum amelioration was investigated by continuously leaching soil columns with a saturated gypsum solution, until the hydraulic conductivity and leachate chemistry stabilized. Extended leaching enabled the full impacts of electrolyte effects and cation exchange to be determined. For the columns packed to 1.4 g/cm3, exchangeable sodium concentrations were reduced from 5.0 ± 0.5 mEq/100 g to 0.41 ± 0.06 mEq/100 g, exchangeable magnesium concentrations were reduced from 13.9 ± 0.3 mEq/100 g to 4.3 ± 2.12 mEq/100 g, and hydraulic conductivity increased to 0.15 ± 0.04 cm/d. For the columns packed to 1.3 g/cm3, exchangeable sodium concentrations were reduced from 5.0 ± 0.5 mEq/100 g to 0.51 ± 0.03 mEq/100 g, exchangeable magnesium concentrations were reduced from 13.9 ± 0.3 mEq/100 g to 0.55 ± 0.36 mEq/100 g, and hydraulic conductivity increased to 0.96 ± 0.53 cm/d. The results of this study highlight that both sodium and magnesium need to be taken into account when determining the suitability of water quality for irrigation of sodic soils and that soil bulk density plays a major role in controlling the extent of reclamation that can be achieved using gypsum applications.

Local experiences, global similarities: Teacher perceptions of the impacts of national testing

Since 2008, Australian schoolchildren in Years 3, 5, 7 and 9 have sat a series of tests each May designed to assess their attainment of basic skills in literacy and numeracy. These tests are known as the National Assessment Program – Literacy and Numeracy (NAPLAN). In 2010, individual school NAPLAN data were first published on the MySchool website which enables comparisons to be made between individual schools and statistically like schools across Australia. NAPLAN represents the increased centrality of the federal government in education, particularly in regards to education policy. One effect of this has been a recast emphasis of education as an economic, rather than democratic, good. As Reid (2009) suggests, this recasting of education within national productivity agendas mobilises commonsense discourses of accountability and transparency. These are common articles of faith for many involved in education administration and bureaucracy; more and better data, and holding people to account for that data, must improve education...

Tornado damage and impacts on nuclear facilities in the United States

This report provides an overview of the tornado impact on the safe operation and shutdown of nuclear power plants in the United States. The motivation for this review stems from the damage and failure of the Fukushima nuclear power plant on March 11, 2011. That disaster warrants comparison of the safety measures in place within the global nuclear power industry.

Solution chemistry impacts on the seawater neutralisation process: Benefits of nanofiltered seawater and reverse osmosis brine

It is well known that the neutralisation of Bayer liquor with seawater causes the precipitation of stable alkaline products and a reduction in pH and dissolved metal concentrations in the effluent. However, there is limited information available on solution chemistry effects on the stability and reaction kinetics of these precipitates. This investigation shows the influence of reactive species (magnesium and calcium) in seawater on precipitate stabilities and volumetric efficiencies during the neutralisation of bauxite refinery residues. Correlations between synthetic seawater solutions and real samples of seawater (filtered seawater, nanofiltered seawater and reverse osmosis brine) have been made. These investigations have been used to confirm that alternative seawater sources can be used to increase the productivity potential of the neutralisation process with minimal implications on the composition and stability of precipitates formed. The volume efficiency of the neutralisation process using synthetic analogues has been shown to be almost directly proportional with the concentration of magnesium. This was further confirmed in the nanofiltered seawater and reverse osmosis brine that showed increases in the efficiency of neutralisation by factors of 3 and 2 compared to seawater, which corresponds with relatively the same increase in the concentration of magnesium in these alternative seawater sources. An assessment of the chemical stability of the precipitates, volumetric efficiency, and discharge water quality have been determined using numerous techniques that include pH, conductivity, inductively coupled plasma optical emission spectroscopy, infrared spectroscopy, thermogravimetric analysis coupled to mass spectrometry and X-ray diffraction. Correlations between synthetic solution compositions and alternative seawater sources have been used to determine if alternative seawater sources are potential substitutes for seawater based on improvements in productivity, implementation costs, savings to operations and environmental benefits.

Impacts of sodic soil amelioration on hydraulic conductivity and deep drainage in the Lower Burdekin

An understanding of the influence of soil chemistry on soil hydraulic properties is of critical importance for the management of sodic soils under irrigation. The hydraulic conductivity of sodic soils has been shown to be affected by properties of the applied solution including pH (Suarez et al. 1984), sodicity and salt concentration (McNeal and Coleman 1966). The changes in soil hydraulic conductivity are the result of changes in the spacing between clay layers in response to changes in soil solution chemistry. While the importance o f soil chemistry in controlling hydraulic conductivity is known, the exact impacts of sodic soil amelioration on hydraulic conductivity and deep drainage at a given location are difficult to predict. This is because the relationships between soil chemical factors and hydraulic conductivity are soil specific and because local site specific factors also need to be considered to determine the actual impacts on deep drainage rates.

How professional development impacts on experienced teachers' perceptions of their ICT practices

Teachers are at the forefront of Information Communication Technology (ICT) use in schools. Teachers face many challenges and competing priorities such as literacy, numeracy and changing curriculum frameworks and are expected to adopt new ICT practices to improve students¿ outcomes. Effective professional development (PD) methods must be identified and implemented. This research examined two core issues: (1) experienced teachers' perceptions of their ICT practices and (2) how PD courses have affected these practices. This case study and its findings has important implications for the implementation of effective PD in schools.

Impacts of wind power integration on small signal stability and low frequency oscillation characteristics of interconnected power systems

为研究风电并网对互联系统低频振荡的影响,基于完整的双馈风电机组模型,定性分析了两区域互联系统在风电机组并网前后阻尼特性的变化情况.从双馈风电机组并网输送距离、并网容量、互联系统联络线传送功率、是否加装电力系统稳定器等多个方面,多角度分析了风电场并网对互联系统小干扰稳定及低频振荡特性的影响.之后,以两个包括两个区域的电力系统为例,进行了系统的计算分析和比较.结果表明,有双馈风电机组接入的互联电力系统,在不同运行模式下,双馈风电机组的并网输送距离、出力水平、联络线传送功率对低频振荡模式的影响在趋势和程度上均有显著差异,这样在对风电场进行入网规划、设计和运行时就需要综合考虑这些因素的影响.

Impacts of tillage and application methods on atrazine and alachlor losses from upland fields: Research paper

The effects of tillage practises and the methods of chemical application on atrazine and alachlor losses through run-off were evaluated for five treatments: conservation (untilled) and surface (US), disk and surface, plow and surface, disk and preplant-incorporated, and plow and preplant-incorporated treatments. A rainfall simulator was used to create 63.5 mm h^-1 of rainfall for 60 min and 127 mm h^-1 for 15 min. Rainfall simulation occurred 24-36 h after chemical application. There was no significant difference in the run-off volume among the treatments but the untilled treatment significantly reduced erosion loss. The untilled treatments had the highest herbicide concentration and the disk treatments were higher than the plow treatments. The surface treatments showed a higher concentration than the incorporated treatments. The concentration of herbicides in the water decreased with time. Among the experimental sites, the one with sandy loam soil produced the greatest losses, both in terms of the run-off volume and herbicide loss. The US treatments had the highest loss and the herbicide incorporation treatments had smaller losses through run-off as the residue cover was effective in preventing herbicide losses. Incorporation might be a favorable method of herbicide application to reduce the herbicide losses by run-off.