Description:
The radial basis integral equation (RBIE) method is derived for the first time to solve potential problems involving material anisotropy. The coefficients of the anisotropic conductivity require the gradient term to be modified accordingly when deriving the boundary integral equation so that the flux expression can be properly accounted. Analyses of the behavior of the anisotropic fundamental solution and its spatial gradients showed that their variations along the subdomain boundaries may be large and they increase as the diagonal components of the material anisotropy become larger. The accuracy of the anisotropic RBIE was found to depend primarily on the accuracy of the influence coefficients evaluations and this precedes the number of nodes used. Root mean squared errors of less than 10(-4)% can be obtained if evaluations of the influence coefficients are sufficiently accurate. An alternative formulation of the anisotropic RBIE was derived. The levels of accuracy obtained were not significantly different from the standard formulation. (C) 2014 Elsevier Ltd. All rights reserved.
Description:
Limited transmission capacity may lead to network congestion which results in wind curtailment during periods of high availability of wind. Conventional congestion management techniques usually involve generation management which may not always benefit large wind farms. This paper investigates the problem in detail and presents an improved methodology to quantify the latent scheduling capacity of a power system taking into account stochastic variation in line-thermal rating, intermittency of wind, and mitigating the risk of network congestion associated with high penetration of wind. The mathematical model converts conventional thermal constraints to dynamic constraints by using a discretized stochastic penalty function with quadratic approximation of constraint relaxation risk. The uniqueness of the approach is that it can limit the generation to be curtailed or re-dispatch by dynamically enhancing the network latent capacity as per the need. The approach is aimed at strategic planning of power systems in the context of power systems with short to medium length lines with a priori known unit commitment decisions and uses stochastic optimization with a two stage recourse action. Results suggest that a considerable level of wind penetration is possible with dynamic line ratings, without adversely affecting the risk of network congestion.
Description:
Limited transmission capacity may lead to network congestion which results in wind curtailment during periods of high availability of wind. Conventional congestion management techniques usually involve generation management which may not always benefit large wind farms. This paper investigates the problem in detail and presents an improved methodology to quantify the latent scheduling capacity of a power system taking into account stochastic variation in line-thermal rating, intermittency of wind, and mitigating the risk of network congestion associated with high penetration of wind. The mathematical model converts conventional thermal constraints to dynamic constraints by using a discretized stochastic penalty function with quadratic approximation of constraint relaxation risk. The uniqueness of the approach is that it can limit the generation to be curtailed or re-dispatch by dynamically enhancing the network latent capacity as per the need. The approach is aimed at strategic planning of power systems in the context of power systems with short to medium length lines with a priori known unit commitment decisions and uses stochastic optimization with a two stage recourse action. Results suggest that a considerable level of wind penetration is possible with dynamic line ratings, without adversely affecting the risk of network congestion.
Description:
As an important means of achieving sustainable development, eco-industrial parks have been given great significance at every level of Chinese governments, and as a result, they have made great strides in China. The increasing pressures of resource constraints and the need for environmental protection have made the achievement of optimal sustainable development performance crucial. Managers of eco-industrial park administrative committees, as decision makers and executors, have a pivotal role in the design, plan, and organization for the sustainable development of eco-industrial parks. Furthermore managers' environmental awareness is important when organizing environmental practices in their eco-industrial parks. This paper seeks to establish the value of the effects of managers' environmental awareness on the relationships between environmental practices and sustainable development performance by presenting an analysis of Chinese eco-industrial park projects. Using an empirical study, this paper first identifies the key environmental practices, directed by managers, which impact the sustainable development performance of Chinese eco-industrial parks. The moderating effect of managers' environmental awareness on the relationships between environmental practices and sustainable development performance is then developed. Our results show that instituting environmental norms for eco-industrial park enterprises, building industrial symbiosis, and providing guidance to key enterprises play significant roles in producing sustainable development performance for eco-industrial parks. Managers' environmental awareness is helpful in driving and transforming environmental practices into sustainable development performance. Our results also provide assistance for designing and implementing environmental practices for sustainable development, recruiting managers with higher environmental awareness, and training managers to improve their environmental awareness so that eco-industrial parks can achieve sustainable development performance.
Description:
The current study examined the measurement and structural invariance of the Center for Epidemiological Studies Depression Scale (CES-D; Radloff, 1977) across ratings provided by older adult men (. n=. 573) and women (. n=. 605). Ratings were modeled in terms of the original four-factor oblique model: a simple structure with correlated factors for Depressed Affect, Positive Affect, Somatic Symptoms, and Interpersonal Difficulties. Multiple-group confirmatory factor analysis supported full measurement and structural invariance, and no sex difference for the four latent factors. These findings indicate good support for measurement and structural invariance of CES-D ratings across older adult men and women. The psychometric and practical implications of the findings are discussed.
Description:
Invasive and noxious weeds are well known as a pervasive problem, imposing significant economic burdens on all areas of agriculture. Whilst there are multiple possible pathways of weed dispersal in this industry, of particular interest to this discussion is the unintended dispersal of weed seeds within fodder. During periods of drought or following natural disasters such as wild fire or flood, there arises the urgent need for 'relief' fodder to ensure survival and recovery of livestock. In emergency situations, relief fodder may be sourced from widely dispersed geographic regions, and some of these regions may be invaded by an extensive variety of weeds that are both exotic and detrimental to the intended destination for the fodder. Pasture hay is a common source of relief fodder and it typically consists of a mixture of grassy and broadleaf species that may include noxious weeds. When required urgently, pasture hay for relief fodder can be cut, baled, and transported over long distances in a short period of time, with little opportunity for prebaling inspection. It appears that, at the present time, there has been little effort towards rapid testing of bales, post-baling, for the presence of noxious weeds, as a measure to prevent dispersal of seeds. Published studies have relied on the analysis of relatively small numbers of bales, tested to destruction, in order to reveal seed species for identification and enumeration. The development of faster, more reliable, and non-destructive sampling methods is essential to increase the fodder industry's capacity to prevent the dispersal of noxious weeds to previously unaffected locales.
Description:
Invasive and noxious weeds are well known as a pervasive problem, imposing significant economic burdens on all areas of agriculture. Whilst there are multiple possible pathways of weed dispersal in this industry, of particular interest to this discussion is the unintended dispersal of weed seeds within fodder. During periods of drought or following natural disasters such as wild fire or flood, there arises the urgent need for 'relief' fodder to ensure survival and recovery of livestock. In emergency situations, relief fodder may be sourced from widely dispersed geographic regions, and some of these regions may be invaded by an extensive variety of weeds that are both exotic and detrimental to the intended destination for the fodder. Pasture hay is a common source of relief fodder and it typically consists of a mixture of grassy and broadleaf species that may include noxious weeds. When required urgently, pasture hay for relief fodder can be cut, baled, and transported over long distances in a short period of time, with little opportunity for prebaling inspection. It appears that, at the present time, there has been little effort towards rapid testing of bales, post-baling, for the presence of noxious weeds, as a measure to prevent dispersal of seeds. Published studies have relied on the analysis of relatively small numbers of bales, tested to destruction, in order to reveal seed species for identification and enumeration. The development of faster, more reliable, and non-destructive sampling methods is essential to increase the fodder industry's capacity to prevent the dispersal of noxious weeds to previously unaffected locales.
Description:
This dissemination study examined the effectiveness of therapist-assisted Internet-delivered Cognitive Behavior Therapy (ICBT) when offered in clinical practice. A centralized unit screened and coordinated ICBT delivered by newly trained therapists working in six geographically dispersed clinical settings. Using an open trial design, 221 patients were offered 12 modules of ICBT for symptoms of generalized anxiety (. n=. 112), depression (. n=. 83), or panic (. n=. 26). At baseline, midpoint and post-treatment, patients completed self-report measures. On average, patients completed 8 of 12 modules. Latent growth curve modeling identified significant reductions in depression, anxiety, stress and impairment (. d=. .65-.78), and improvements in quality of life (. d=. .48-.66). Improvements in primary symptoms were large (. d=. .91-1.25). Overall, therapist-assisted ICBT was effective when coordinated across settings in clinical practice, but further attention should be given to strategies to improve completion of treatment modules.
Description:
The derivatization of thiamin vitamers to their respective thiochrome by ferricyanide to facilitate fluorescence detection following separation by HPLC provides a powerful analytical tool. However the polyphenolic compounds in red wine readily interact with ferricyanide, reducing the effectiveness of ferricyanide oxidation in the derivatization of thiamin. We describe a method to facilitate the removal of polyphenolic compounds that interfere with the ferricyanide derivatization of thiamin. Polyvinylpolypyrrolidone afforded the total removal of phenolic compounds from red wines and allowed a spike recovery of thiamin vitamers (101% for thiamin; 104% for TMP; and 100% for TDP) in a wide range of red wines. This research found that Merlot styles of red wine contained the highest concentration of total thiamin (29.01 ng/mL) while Pinot Noir wines contained the lowest total concentration (8.27 ng/mL).
Description:
This study concentrates on optimizing a multi-state weighted k-out-of-n system consisting of different types of reparable components. An optimization model is developed to decide upon both optimal redundancy allocation and best maintenance activities for reliability allocation. The optimization model is to maximize system reliability and minimize system cost simultaneously. To reach this goal, a financial view has been employed to estimate the system reliability, and combine it with system cost. The proposed model determines the number of each component type in the system, and the maintenance actions and the time at which they should be applied. Also, the model is programmed by MATLAB, and Genetic Algorithm is used to solve a practical case. (C) 2016 The Society of Manufacturing Engineers. Published by Elsevier Ltd. All rights reserved.
Description:
Lakes are an important source and sink of atmospheric CO2, and thus are a vital component of the global carbon cycle. However, with scarce data on potentially important subtropical and tropical areas for whole continents such as Australia, themagnitude of large-scale lake CO2 emissions is unclear. This study presents spatiotemporal changes of dissolved inorganic carbon and water—to—air interface CO2 flux in the two of Australia's largest connected, yet geomorphically different freshwater lakes (Lake Alexandrina and LakeAlbert, South Australia), during drought (2007 to September—2010) and post-drought (October 2010 to 2013). Lake levels in the extreme drought were on average approximately 1 m lower than long-term average (0.71 m AHD). Drought was associated with an increase in the concentrations of dissolved inorganic species, organic carbon, nitrogen, Chl-a and major ions, aswell aswater acidification as a consequence of acid sulfate soil (ASS) exposure, and hence, had profound effects on lake pCO2 concentrations. Lakes Alexandrina and Albert were a source of CO2 to the atmosphere during the drought period, with efflux ranging from0.3 to 7.0mmol/m2/d. The lake air–water CO2 flux was negative in the post-drought, ranging between−16.4 and 0.9mmol/m2/d. The average annual CO2 emission was estimated at 615.5 × 106 mol CO2/y during the drought period. These calculated emission rates are in the lower range for lakes, despite the potential for drought conditions that shift the lakes from sink to net source for atmospheric CO2. These observations have significant implications in the context of predicted increasing frequency and intensity of drought as a result of climate change. Further information on the spatial and temporal variability in CO2 flux from Australian lakes is urgently warranted to revise the global carbon budget for lakes.