Non-linear autoregressive neural network approach for inside air temperature prediction of a pillar cooler

The volcanic plate made pillar cooler system is designed for outdoor spaces as a heat exchanging medium and reduces the outcoming air temperature which flows through the exhaust port. This paper proposes the use of artificial neural networks (ANNs) to predict inside air temperature of a pillar cooler. For this purpose, at first, three statistically significant factors (outside temperature, airing and watering) influencing the inside air temperature of the pillar cooler are identified as input parameters for predicting the output (inside air temperature) and then an ANN was employed to predict the output. In addition, 70%, 15% and 15% data was chosen from a previously obtained data set during the field trial of the pillar cooler for training, testing and validation, respectively, and then an ANN was employed to predict inside air temperature. The training (0.99918), testing (0.99799) and validation errors (0.99432) obtained from the model indicate that the artificial neural network model (NARX) may be used to predict inside air temperature of pillar cooler. This study reveals that, an ANN approach can be used successfully for predicting the performance of pillar cooler.     

Multiwell Technique of Saline and Nonsaline Groundwater Pumping from Coastal Aquifers

In this article, the authors explore their recent study, which introduces the concept of extracting saline water and fresh water simultaneously from groundwater aquifers to produce water that is suitable for irrigation. To achieve these results, multiwell modeling concepts are used to exploit both the saline and nonsaline aquifer domains from geologic formations where a freshwater aquifer domain is either underlain or overlain by a saline aquifer domain. The water from these domains are either mixed to an acceptable salinity level after independent withdrawal from separate, saline or nonsaline domains present within the same aquifer, or mixed from the domains to achieve acceptable levels of salinity before withdrawal.     

Impact of landfill liner time–temperature history on the service life of HDPE geomembranes

The observed temperatures in different landfills are used to establish a number of idealized time–temperature histories for geomembrane liners in municipal solid waste (MSW) landfills. These are then used for estimating the service life of different HDPE geomembranes. The predicted antioxidant depletion times (Stage I) are between 7 and 750 years with the large variation depending on the specific HDPE geomembrane product, exposure conditions, and most importantly, the magnitude and duration of the peak liner temperature. The higher end of the range corresponds to data from geomembranes aged in simulated landfill liner tests and a maximum liner temperature of 37 °C. The lower end of the range corresponds to a testing condition where geomembranes were immersed in a synthetic leachate and a maximum liner temperature of 60 °C. The total service life of the geomembranes was estimated to be between 20 and 3300 years depending on the time–temperature history examined. The range illustrates the important role that time–temperature history could play in terms of geomembrane service life. The need for long-term monitoring of landfill liner temperature and for geomembrane ageing studies that will provide improved data for assessing the likely long-term performance of geomembranes in MSW landfills are highlighted.     

Pyrolysis kinetics behavior of solid tire wastes available in Bangladesh

Pyrolysis kinetics of available bicycle/rickshaw, motorcycle and truck tire wastes in Bangladesh have been investigated thermogravimetrically in a nitrogen atmosphere at heating rates of 10 and 60 degrees C/min over a temperature range of 30-800 degrees C. The three tire wastes exhibited similar behaviors in that, when heating rate was increased, the initial reaction temperature decreased but the reaction range and reaction rate increased. The percentage of total weight loss was higher for truck tire waste and lower for bicycle/rickshaw tire waste. The pyrolysis of truck tire waste was found to be easier than that of bicycle/rickshaw and motorcycle tire wastes while it was comparatively more difficult for motorcycle tire waste. The overall rate equation for the three tire wastes has been modeled satisfactorily by one simplified equation from which the kinetic parameters of unreacted materials based on the Arrhenius form can be determined. The predicted rate equation compares fairly well with the measured TG and DTG data. DTA curves for all of the samples show that the degradation reactions are three main exotherms and one endotherm.     

Modeling and simulation of industrial water demand of Beijing municipality in China

Statistic and econometric regression models were established in this study to analyze and predict industrial water demand, water deficits, and their future uncertainty in Beijing—a Chinese city with a severe water stress problem. A forecasting model was selected based on a modeling evaluation by comparing predictions with observations. Four scenarios were designed to simulate and analyze the future uncertainty of industrial water demand and the water deficit of Beijing. The modeling results for industrial water demand suggested that Beijing industry would face a water deficit between 3.06 × 10⁸ m³ in 2008 and 2.77×10⁸ m³ in 2015, though its industrial water demand would decrease from 6.31×10⁸ m³ to 4.84 ×10⁸ m³ during this period of time. Results from simulated scenario illustrated that, due to the extreme water scarcity situation, industry in Beijing would still face a serious water deficit problem even with a very optimistic scenario for the future.     

Movement towards a low carbon emitted environment: a test of some factors in Malaysia

There exists a high global concern in different nations on environmental sustainability especially at the focal stage of increased economic growth and development process due to high level of environmental degradation and pollution. The major aim of this study was to empirically examine how to minimise carbon emissions (CO₂) in Malaysia which are mainly caused by energy production, fossil fuel consumption, population density and economic growth. The study adopted the method of autoregressive distributed lag bound testing approach to analyse the data for the period 1971–2011. The study found that economic growth in Malaysia has a direct relationship with CO₂ emissions in both the short run and the long run. Similarly, there is a positive relationship between fossil fuel consumption and CO₂ emissions over the same period. Population density was found to have positive impacts on CO₂ emissions. Contrarily, the relationship between the activities of energy production and pollution is negative in the long run. The study recommends that a targeted GDP growth rate should be set with the consideration to avoid more environmental pollution. In addition, the positive impact of fossil fuel consumption on the environmental pollution implies that there is a need to make and implement policies that will encourage the use of public transportation system more than private transportations. That is, the unnecessary use of private vehicles should be discouraged in order to reduce the extent of fossil fuel consumption.     

Tracking Cholera in Coastal Regions Using Satellite Observations1

Jutla, Antarpreet S., Ali S. Akanda, and Shafiqul Islam, 2010. Tracking Cholera in Coastal Regions Using Satellite Observations. Journal of the American Water Resources Association (JAWRA) 46(4): 651-662. DOI: 10.1111/j.1752-1688.2010.00448.x Abstract: Cholera remains a significant health threat across the globe. The pattern and magnitude of the seven global pandemics suggest that cholera outbreaks primarily originate in coastal regions and then spread inland through secondary means. Cholera bacteria show strong association with plankton abundance in coastal ecosystems. This review study investigates the relationship(s) between cholera incidence and coastal processes and explores utility of using remote sensing data to track coastal plankton blooms, using chlorophyll as a surrogate variable for plankton abundance, and subsequent cholera outbreaks. Most studies over the last several decades have primarily focused on the microbiological and epidemiological understanding of cholera outbreaks. Accurate identification and mechanistic understanding of large scale climatic, geophysical, and oceanic processes governing cholera-chlorophyll relationship is important for developing cholera prediction models. Development of a holistic understanding of these processes requires long and reliable chlorophyll datasets, which are beginning to be available through satellites. We have presented a schematic pathway and a modeling framework that relate cholera with various hydroclimatic and oceanic variables for understanding disease dynamics using the latest advances in remote sensing. Satellite data, with its unprecedented spatial and temporal coverage, have potentials to monitor coastal processes and track cholera outbreaks in endemic regions.     

Sustainable development in Asia: the current state and policy options

Over the past decades, many Asian economies have achieved striking levels of economic growth. This economic growth has been necessary in order to fulfil the material needs and aspirations of growing populations. However, it has also been accompanied by substantial environmental degradation. While the precise interactions between economic growth, economic development and environmental degradation is subject to controversy and a comprehensive assessment of the Asian environment may be required to fully understand this relationship and the present conditions of the environment, it is argued in this paper that the achievement of sustainable economic development and the harmonizing of economic and environmental objectives will not be possible without deliberate policy interventions. Such policies need to incorporate a regional dimension in the form of institution building, in parallel to the concept of regional economic growth. The article focuses on the current problems of environmental and natural resource degradation in Asia, within a possible conceptual framework of impoverishing or unsustainable economic growth, and suggests a set of policies that need to be adopted in order to solve current difficulties.     

ESTIMATING THE PROBABILITY OF EXCEEDING GROUNDWATER QUALITY STANDARDS1

ABSTRACT: A model for estimating the probability of exceeding groundwater quality standards at environmental receptors based on a simple contaminant transport model is described. The model is intended for locations where knowledge about site-specific hydrogeologic conditions is limited. An efficient implementation methodology using numerical Monte Carlo simulation is presented. The uncertainty in the contaminant transport system due to uncertainty in the hydraulic conductivity is directly calculated in the Monte Carlo simulations. Numerous variations of the deterministic parameters of the model provide an indication of the change in exceedance probability with change in parameter value. The results of these variations for a generic example are presented in a concise graphical form which provides insight into the topology of the exceedance probability surface. This surface can be used to assess the impact of the various parameters on exceedance probability.